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PMC10521587
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Cureus
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Eosinophilic Enteritis Flare-Up Mimicking Acute Gastroenteritis: A Rare Case
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27-08-2023
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Eosinophilic enteritis is a rare subset of eosinophilic gastrointestinal disorders. It typically presents with chronic symptoms of abdominal pain, nausea, vomiting, diarrhea, and ascites. However, the clinical presentation can vary due to acute flare-ups. Here, we present a case of eosinophilic enteritis in a young female patient with intractable vomiting and diarrhea, mimicking acute gastroenteritis in the absence of other gastrointestinal symptoms. This case illustrates the challenge of diagnosing acute and diverse presentations of eosinophilic enteritis. It also highlights the importance of promptly treating and confirming the diagnosis through urgent tissue histopathology in adolescents with unexplained vomiting and diarrhea.
|
[
"Eosinophilic gastrointestinal by its association with GI symptoms and eosinophil-rich infiltration of the intestinal mucosa, without secondary intestinal eosinophilia [ ]. After eosinophilic esophagitis, both eosinophilic gastroenteritis and EE represent the most frequent subset of disorders [ ]. Although the disease has been described in case reports and reviewed multiple times, estimating its true incidence remains challenging due to many undiagnosed and unreported patients.",
"The exact pathogenesis of EE is unknown; however, the literature suggests the roles of immunoglobulin E with intractable vomiting, diarrhea, and severe dehydration. In the absence of fever and abdominal pain, she was managed as a suspected acute gastroenteritis. Her blood workup revealed peripheral eosinophilia, elevated serum IgE levels, and high C-reactive protein scan of the abdomen showed findings of multiple areas of segmental thickening of the bowel wall in the duodenum and proximal jejunum, as noted in Figure .",
"Suspected for an underlying gastric outlet obstruction and/or inflammatory bowel disease, upper GI endoscopy was performed on the third day of hospitalization. Although non-specific, endoscopic findings ruled out gastric outlet obstruction but displayed patchy areas of erythema in the duodenum and proximal jejunum, as shown in Figure . The biopsy was taken from multiple segments of the intestine, and histopathology was ordered. With findings consistent with eosinophilic GI disease, i.e., peripheral eosinophilia, elevated IgE levels, and non-specific erosions on endoscopy, she was empirically started on dexamethasone infusion of 30 mg per day.",
"On the fifth day of hospitalization, her symptoms started improving. Her vomiting and diarrhea resolved completely by the tenth day in hospital. She was shifted to oral prednisolone 20 mg twice daily, montelukast 10 mg once daily, and ketotifen 2 mg once daily. A repeated blood count performed on December 11, 2022, showed normal eosinophil count, normal CRP levels, decreasing IgE levels, and declining pattern in ESR. Subsequently, she was discharged to home on oral medications.",
"Upon follow-up a week later, this patient had no GI complaint, and a tapering regimen of prednisolone was planned at 5 mg per week for four weeks until discontinuation. The allergy food panel was found to be normal. Furthermore, her histopathology report, which was also available at the follow-up visit, revealed dense infiltrates of eosinophils with degranulation in the lamina propria and muscularis mucosa of the duodenum and jejunum, as shown in Figure . This confirmed our suspected diagnosis of EE.",
"Eosinophilic GI diseases are a rare group of chronic and immune-mediated conditions that can affect any segments of the GI tract, including esophagus and pro-inflammatory cytokines within the gut wall, amplifying inflammation. Additional factors such as interleukin-33, eosinophilic-like receptors), seen in nearly 20%-80% of patients [ ]. Similarly, other non-specific laboratory findings such as elevated IgE levels, hypoalbuminemia, iron deficiency, and increased inflammatory markers such as CRP and ESR may also be present [ ]. Imaging studies are highly non-specific and may show gut wall thickening. It may also help in excluding other secondary causes of GI disease [ ]. Likewise, upper GI endoscopy may also show non-specific findings of erythema, erosions, edema, or nodules [ ]. In our patient’s case, peripheral eosinophilia, elevated IgE levels, and high CRP and ESR levels were observed, with the latter two returning to baseline after treatment. In the absence of secondary causes of eosinophilia, the biopsy confirmed our final diagnosis of EE.",
"The treatment of EE poses a challenge due to the absence of clear guidelines. Non-pharmacological approaches involve the elimination of diets that trigger atopy and/or allergic reactions, although data on dietary elimination are insufficient in the current literature. Pharmacological therapies are the mainstay of treatment. Prednisolone is a widely used regimen, given at the dose of 1 mg per kg per day for few weeks followed by a gradual tapering over 6 to 8 weeks. Other therapies options include leukotriene inhibitors (e.g., montelukast 10 mg once daily), mast cell stabilizers (e.g., sodium cromoglycate 200 mg thrice daily), anti-histamines (e.g., ketotifen 1-2 mg twice daily), and medications such as azathioprine and biologics (e.g., mepolizumab, omalizumab, infliximab, adalimumab) [ , ]. Our patient received IV dexamethasone initially and subsequently took oral prednisolone for a duration of eight weeks, along with montelukast and ketotifen for 12 weeks. She responded very well to this combination therapy. Moreover, during the three-month follow-up, no disease flare was observed.",
"EE is a rare disorder characterized by a constellation of non-specific GI symptoms, laboratory findings, and imaging abnormalities. Our case presents a unique manifestation of EE, marked by intractable vomiting and diarrhea upon presentation, imitating the symptoms of acute gastroenteritis. In a case such as ours, it is essential to remember that EE can exhibit an acute flare and create diagnostic and therapeutic challenges for physicians. A high index of suspicion becomes imperative in such cases. Given the scarcity of literature on the acute flare aspect of EE, we emphasize the need for further extensive research to comprehend the diverse facets of this intricate disorder."
] |
PMC10813894
|
Children
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Statins—Beyond Their Use in Hypercholesterolemia: Focus on the Pediatric Population
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17-01-2024
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Statins are a class of medications primarily used in adults to lower cholesterol levels and reduce the risk of cardiovascular events. However, the use of statins in children is generally limited and carefully considered despite the well-documented anti-inflammatory, anti-angiogenic, and pro-apoptotic effects, as well as their effect on cell signaling pathways. These multifaceted effects, known as pleiotropic effects, encompass enhancements in endothelial function, a significant reduction in oxidative stress, the stabilization of atherosclerotic plaques, immunomodulation, the inhibition of vascular smooth muscle proliferation, an influence on bone metabolism, anti-inflammatory properties, antithrombotic effects, and a diminished risk of dementia. In children, recent research revealed promising perspectives on the use of statins in various conditions including neurological, cardiovascular, and oncologic diseases, as well as special situations, such as transplanted children. The long-term safety and efficacy of statins in children are still subjects of ongoing research, and healthcare providers carefully assess the individual risk factors and benefits before prescribing these medications to pediatric patients. The use of statins in children is generally less common than in adults, and it requires close monitoring and supervision by healthcare professionals. Further research is needed to fully assess the pleiotropic effects of statins in the pediatric population.
|
[
"Statins primarily function by inhibiting 3-hydroxy-3-methylglutaryl-coenzyme A primarily due to elevated LDL cholesterol, can be attributed to the cumulative effect of multiple single nucleotide variants scattered throughout the genome [ ]. These individuals are at a high risk of developing atherosclerosis due to lifelong exposure to elevated LDL-C levels [ ]. Therefore, early intervention is crucial in managing this condition and reducing the risk of complications.",
"For children diagnosed with heterozygous familial hypercholesterolemia levels remain persistently elevated despite 3–6 months of lifestyle modifications [ ]. In cases where children with heterozygous FH have more severe LDL-C abnormalities, statin treatment may be initiated alongside therapeutic lifestyle changes [ ].",
"The therapy initiation algorithm is based on fasting LDL-C values and the presence or absence of cardiovascular risk factors. Children and adolescents with LDL-C ≥ 250 mg/dL and/or triglycerides levels in children and adolescents with hypercholesterolemia. A recent meta-analysis comprising data from eight randomized controlled trials and 1025 children with familial hypercholesterolemia demonstrated that the lipid profile was significantly improved after statin therapy with a mean reduction of 75 mg/dL in the case of TC, 11.5 mg/dL in the case of TG, and 75 mg/dL in the case of LDL-C, with a mean increase of 14.3 mg/dL in the case of HDL-C [ ]. In another comprehensive meta-analysis of 10 randomized controlled trials involving 1191 children aged 13.3 ± 2.5 years, statins have shown effectiveness in reducing TC by 25% and TG by 8% while increasing HDL-C by 3% when compared with a placebo [ ].",
"While statins are generally well tolerated, there are some potential safety concerns to be aware of. Common side effects of statin use in children may include gastrointestinal symptoms such as abdominal pain, nausea, or diarrhea [ ]. Muscle-related side effects, such as myalgia or elevated creatine kinase levels, can also occur but are rare in children [ ]. Serious adverse events associated with statin use, such as liver dysfunction or rhabdomyolysis, have been also rarely reported in the pediatric population [ ]. According to Khoury et al., liver toxicity, myositis, and rhabdomyolysis were no more frequently reported in children receiving statins than in those receiving placebos and had no impact on growth or development [ ]. However, in the case of pre-existing liver disease, such as non-alcoholic fatty liver disease, liver function and transaminase levels should be monitored more closely when initiating statin therapy [ ]. A fasting lipid-profile should be recommended 4 to 8 weeks after statin initiation; if adequate LDL-C reduction is observed, a fasting lipid profile should be repeated every 3–6 months in the first 112 months and longitudinally every 6–12 months [ ]. Transaminases and creatine phosphokinase levels should be checked at baseline and also in the case of new symptoms [ ]. Following the initiation of statin therapy, it is recommended to regularly monitor liver enzymes and creatine phosphokinase levels at 1–2 months, assess liver enzymes at 3–6 months, and periodically thereafter. It is important to note that the routine monitoring of creatine phosphokinase is not necessary as it may lead to incidental elevations of muscular enzymes that could be attributed to physical activity [ ].",
"Up to the present, no cases of rhabdomyolysis were reported in children [ ]. In a cohort of 1501 children aged 14 ± 4 years old treated with one of two low dose statins, among other medications, macrolides, antifungal azoles, protease inhibitors, cyclosporine, and grapefruit should be avoided, with dose adjustments often needed for calcium channel blockers and amiodarone [ ]. In the case of fluvastatin, pitavastatin, and rosuvastatin, which are substrates of CYP2C9, cyclosporine should be avoided [ ]. As pravastatin is the only statin not metabolized by a CYP isoenzyme, it may be a more appropriate choice for patients at risk for adverse drug interactions [ ]. Also, the concurrent use of statins and gemfibrozil should be avoided, as gemfibrozil inhibits OATP1B1, a hepatic drug membrane transporter, and can hinder the hepatic glucuronidation of statins, leading to elevated plasma concentrations of statins and their metabolites [ ].",
"While specific prevalence rates may vary across different regions and populations, studies have indicated an overall increase in the prevalence of lipid metabolism disorders in children, not only as a consequence of an increasing number of primary hypercholesterolemia cases, but also due to an epidemic of secondary hypercholesterolemia cases [ ]. The various causes of secondary hypercholesterolemia are detailed in .",
"In diabetes, the role of HMG-CoA reductase inhibitors is controversial and unclear [ ]. Joyce et al. reported a positive association with an increased likelihood of developing type 2 diabetes in children without dyslipidemia who took statins, not observed in statin-treated dyslipidemia children [ ]. Unfortunately, this article fails to explicitly identify the actual indications for statin use in the non-dyslipidemia group, and only compares the outcomes in the statin-exposed and non-exposed groups in terms of type 2 diabetes occurrence. In this respect, one needs to keep in mind the rapid progression of adolescent- and young adult-onset type 2 diabetes [ ] and the high number of complications and severe metabolic phenotypes, as shown by studies such as TODAY and RISE [ , , ].",
"Although cited as a secondary cause of hypercholesterolemia, the association between dyslipidemia and atherosclerosis in Kawasaki disease is still not certain [ ]. In this context, we will further discuss the use of statins in Kawasaki disease due to their pleiotropic effects.",
"Kawasaki disease, also known as Kawasaki syndrome, is an acute febrile illness of unknown cause primarily observed in children under the age of 5. While it is generally considered a rare disease [ ], it can have serious complications if left untreated due to the development of coronary artery abnormalities, which can lead to coronary artery aneurysms, depressed myocardial contractility and heart failure, myocardial infarction, and arrhythmias [ ].",
"As statins have been found to have positive effects on inflammation, endothelial function, and oxidative stress, recommendations from the American Heart Association [ , ] and Japanese Circulation Society [ ] encourage the empirical use of statins for children with Kawasaki disease and past or current aneurysms.",
"In this context, it is important to understand the mechanisms beyond the positive impact on inflammation and coronary artery abnormalities. In a murine study, atorvastatin demonstrated anti-atherosclerotic effects by enhancing the function of endothelial cells in artificially induced Kawasaki-like vasculitis [ ]. Motoji et al. showed that the use of statins may be able to prevent the cardiovascular events associated with Kawasaki disease by stimulating the expression of endothelial nitric oxide synthase and no apparent adverse effect on growth or development were reported [ ].",
"The safety of atorvastatin was also investigated in a Phase I/IIa 2-center dose-escalation study including 34 children aged 2–17 years old with Kawasaki disease complicated by a coronary artery aneurysm [ ]. The authors concluded that after 6 weeks of treatment with 0.75 mg/kg/day of atorvastatin, no serious adverse events were reported [ ]. Additionally, a small study including 13 male children aged 2–10 years found that 6 months of pravastatin therapy improved chronic vascular inflammation and endothelial dysfunction in children with Kawasaki disease with minimal to no adverse effects [ ].",
"Besides Kawasaki disease, the statins showed potential benefits in chronic vasculitis such as Behçet’s and rheumatoid arthritis due to their anti-inflammatory, anti-oxidant, and endothelial-repairing properties [ ]. Recent research showed that the anti-inflammatory effects of statins are based on complex mechanisms: statins can suppress TLR4 stabilization [ ]. However, further studies are needed to unravel the potential use of these mechanisms in pediatric cardiovascular and inflammatory diseases. As statins exhibit both a lipid-lowering effect in addition to an anti-inflammatory effect [ ], their use was also investigated in heart-transplanted patients. In adults, statins have been found to have several beneficial effects [ ], and early use reduced the cardiac allograft vasculopathy and the risk of the accelerated progression of atherosclerosis [ ]. In heart-transplanted children, the pleiotropic effects of statins are still understudied. Moreover, the results of the available studies on the impact of statins in this particular population show controversial and even conflicting results. In a study comprising 78 children aged 4.8 to 14.7 years old who underwent a heart transplant, the use of statins was associated with a significant decrease in the incidence of acute cellular rejection and post-transplant lymphoproliferative disease, but with no significant decrease in the risk of coronary artery vasculopathy even with early statin initiation [ ]. In a retrospective study including 964 heart transplant recipients aged 5–18 years old, Greenway et al. reported no effects of statin use regarding overall survival up to 5 years post-transplant and the risk of cardiac allograft vasculopathy and post-transplant lymphoproliferative disease [ ]. These results are concordant with a recent study conducted by Townsend et al. in 3485 pediatric heart transplant recipients, showing no statistically significant difference regarding the graft survival and the incidence of cardiac allograft vasculopathy between children receiving consecutive statin therapy and those with intermediate use or no statin therapy [ ]. Interestingly, pravastatin effectively lowered the TC and LDL-C and improved the compositional properties of LDL and HDL due to their anti-inflammatory properties. In a randomized, double-blind study, Moazen-Zadeh et al. reported a positive impact on irritability and hyperactivity/noncompliance in children aged 4–12 years old treated with risperidone is limited and even conflicting. In a murine study, Mucha et al. reported that simvastatin did not improve the clinical and biological patterns of mdx in a study of 15 patients aged between 6 and 31 years old [ ]. The role of statins in Rett syndrome, an X-linked disease characterized by the progressive development of neurological and motor dysfunction, was suggested by a murine study conducted by Buchovecky et al., in which statins had a favorable impact on the systemic imbalance of the lipid profile, motor symptoms, and longevity in Mecp2 pathway, whose activation may result in medulloblastoma, and, unlike other inhibitors of this pathway, such as sonedigib and vismodegib, effectively suppressed tumor growth in young mice, without causing any defects in bone development [ ]. In humans, a phase 1 study conducted in children with relapsed/refractory solid and central nervous system tumors reported that plasma interleukin 6 in contrast to data from the group receiving atorvastatin, which was associated with a tumor incidence of 12.5% and mean tumor volume of 2.3 ± 0.2 mm^(3) [ ]. In humans, the results of the available observational and randomized studies are controversial and insufficient to establish a consensus regarding the use of statins as chemo-preventive drugs in children [ ].",
"The future perspectives of statin use in children are promising, considering their pleiotropic effects in various diseases. While the primary indication for statins in pediatric populations remains the management of dyslipidemia, their potential applications in autoimmune and inflammatory diseases, neurological disorders, and oncologic diseases warrant further investigation.",
"Future research should focus on optimizing dosing, evaluating long-term safety, and conducting well-designed clinical trials to establish the efficacy and safety of statins in children with various conditions. In the context of pediatric cancers, the use of statins is still in its early stages, and more research is needed to fully understand their efficacy and safety in this specific population. Future studies may focus on investigating the potential benefits of statins as adjuvant therapy in combination with standard cancer treatments, such as chemotherapy or radiation therapy.",
"The potential of statins to prevent cancers is also an area of ongoing research and investigation. While some studies suggest that statins may have a chemo-preventive effect and reduce the risk of certain cancers, the evidence is not yet conclusive. Further research, including large-scale clinical trials and long-term studies, is needed to better understand the role of statins in cancer prevention.",
"Also, it would be valuable to examine the mechanisms of action through which statins may exert their effects on neurologic conditions in children, as well as the optimal dosage and duration of treatment. As the prevalence of autism in children has shown an increasing trend over the past few decades [ ], long-term follow-up studies are needed to assess the safety and efficacy of statins in this specific context.",
"Statin therapy has proven to be highly effective in reducing cardiovascular events and mortality in patients with dyslipidemia. However, there is considerable heterogeneity in the treatment response among patients, highlighting the need for personalized medicine approaches. The identification of specific biomarkers that can predict treatment response to statins is crucial for optimizing patient outcomes and resource allocation. It would be valuable to assess the significance of specific biomarkers regarding the suitable moment of treatment initiation, the early identification of potential complications, and the effectiveness in targeting specific diseases. For instance, endothelial function markers such as endothelial nitric oxide synthase in genes involved in lipid metabolism, have shown promise in predicting statin response [ ]. The role of specific genes as strong candidate genes including CETP , HMGCR , SLCO1B1 , ABCB1 , and CYP3A4 / 5 should be further studied in relation with treatment outcomes [ ]. By incorporating genetic, lipid, inflammatory, and metabolic biomarkers into clinical decision-making, clinicians can better tailor statin treatment to individual patients. Further research and validation of these biomarkers are warranted to establish their clinical utility and integration into routine practice. This personalized approach has the potential to improve treatment outcomes, reduce adverse effects, and optimize resource allocation.",
"The pleiotropic effects of statins sparked interest in exploring their potential use in various diseases. In addition to lipid-lowering effects, statins have been shown to have anti-inflammatory, antioxidant, and immunomodulatory properties. In children, HMG-CoA reductase inhibitors showed incontestable benefits with minimal side effects in various conditions associated with disturbances in lipid profile parameters. Besides the role of statins in hypercholesterolemia, innovative potential indications include neurological, oncologic, and cardiovascular diseases, as well as special situations such as transplanted children. While the use of statins in children for these conditions is still being studied, their pleiotropic effects offer promising possibilities for expanding their therapeutic applications beyond cholesterol management. However, it is important to note that further research is needed to fully understand the safety and efficacy of statins in these contexts before widespread use can be recommended."
] |
PMC10137892
|
Gels
|
Nano-Gels: Recent Advancement in Fabrication Methods for Mitigation of Skin Cancer
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13-04-2023
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In the 21st century, melanoma and non-melanoma skin cancers have become an epidemic outbreak worldwide. Therefore, the exploration of all potential preventative and therapeutic measures based on either physical or bio-chemical mechanisms is essential via understanding precise pathophysiological pathways (Mitogen-activated protein kinase, Phosphatidylinositol 3-kinase Pathway, and Notch signaling pathway) and other aspects of such skin malignancies. Nano-gel, a three-dimensional polymeric cross-linked porous hydrogel having a diameter of 20–200 nm, possesses dual properties of both hydrogel and nanoparticle. The capacity of high drug entrapment efficiency with greater thermodynamic stability, remarkable solubilization potential, and swelling behavior of nano-gel becomes a promising candidate as a targeted drug delivery system in the treatment of skin cancer. Nano-gel can be either synthetically or architectonically modified for responding to either internal or external stimuli, including radiation, ultrasound, enzyme, magnetic, pH, temperature, and oxidation-reduction to achieve controlled release of pharmaceuticals and several bio-active molecules such as proteins, peptides, genes via amplifying drug aggregation in the active targeted tissue and reducing adverse pharmacological effects. Several drugs, such as anti-neoplastic biomolecules having short biological half-lives and prompt enzyme degradability capacity, must be appropriate for administration employing either chemically bridged or physically constructed nano-gel frameworks. The comprehensive review summarizes the advancement in the preparation and characterization methods of targeted nano-gel with enhanced pharmacological potential and preserved intracellular safety limits for the mitigation of skin malignancies with a special emphasize on skin cancer inducing pathophysiological pathways and prospective research opportunities for skin malignancy targeted nano-gels.
|
[
"The concept “novel drug delivery system” into different categories such as physically-chemically cross-linked, hybrid nano-gel, polymeric, bio-mimetic nano-gel, pH, thermo, magnetic, hypoxia, ultrasound, enzyme, and reduction responsive nano-gel on the basis of synthesis procedure, nature of materials used and responsive towards stimuli respectively [ , ]. The swellable property of nano-gel makes them able to expand when in contact with physiological fluids providing flexibility to be near the targeted region drugs under particular physiological circumstances and increasing the dispersion of medicaments [ ]. Nano-gels can be either synthetically modified to incorporate numerous ligands for targeted drug delivery or controlled drug release or primarily a transporter architecture for delivering pharmaceuticals and several bio-active compounds such as genes, proteins, etc. [ , , ]. Depending on the type and properties of both drug and nano-gel being utilized as well as desired release pattern, there are many techniques to load drugs into them, such as physical entrapment, immunosuppressive disorders, use of heavy metals, pesticides, etc. resulting in the damage of DNA molecule of melanocytes that raises intracellular oxygen radicals. These mutations cause uncontrollable cell proliferation, expression, and immortalization, attributing to the unrestricted stimulation of multiple cell signaling pathways [ ]. The pathogenesis, signaling, and cellular pathways of melanomas are described below:",
"Almost all forms of melanomas stimulate the MAPK cascade that controls cell proliferation, growth, and migration. Melanoma instances are characterized by excessive activation when the growth factors stimulate tyrosine kinase receptors after binding with it and resulting in the activation of the RAS family monomeric G protein, Neuroblastoma RAS viral oncogene homolog of BRAF gene mutations are caused by the conversion of thymidine to adenine, and the kinase domain of the protein molecule is activated as a result of the valine being switched out for glutamate [ , ]. Other protein substitutions, available in V600K mutations tumor suppressor gene, which inhibits NRAS signaling, as well as the amplification and/or subsequent activation of a number of growth factor receptors, including c-MET, the epidermal growth factor receptor exhibited activating RAS mutations, with NRAS mutations becoming the most prevalent. Exceptionally frequent NRAS and BRAF mutations demonstrate that merely a single mutation in any one of the two genes is adequate to trigger the MAPK pathway [ ]. The predominance of NRAS mutations is identified in congenital nevi, which are infrequent in nevi. Spitz nevi and NRAS mutations are typically linked [ ]. Mutations in the NRAS or BRAF genes are found in 80% of cases of melanocytic nevi activation, a key regulator necessary for myocyte maturation having an impact on the recurrence of some melanomas or cognitive debilitation of phosphatase and tensin homolog deleted on chromosome 10 are phosphorylated as a result of AKT [ ]. Tumor development is also associated with the amplification of the tyrosine kinase receptor c-MET along with its ligand HGF is mainly responsible for mediating the hypoxia response resulting in the activation of numerous genes related to angiogenesis, invasion, and metastasis and promotion of PI3K pathway developing tumor and transforming melanocyte in the hypoxic human skin microenvironment. Due to inadequate vascularization, tumor hypoxia develops with melanoma growth, which raises HIF and promotes melanogenesis, and melanoma progression, having a detrimental prognostic impact [ ].",
"The Notch signaling system, comprised of regulatory proteins, negative and positive regulators, a family of the receptor synthesized photo-chemically stable citric acid and pentane-1,2,5-triol loaded spherical and negatively, click chemistry cross-linking, and photo-induced cross-linking are some examples of chemical cross-linking techniques. The study reported that curcumin-loaded Carbopol, capmul [ ]. Many variables, such as the choice of surface active agents, the quantity of both monomer and cross-linker and the pH of specific reaction media, all have an impact on the size of nano-gels [ ]. The drawback of the method is that the reaction media is an organic solvent. The purification of the produced nano-gels will be problematic if emulsifiers or co-emulsifiers are present. A degradable poly polymerization technique, a polymer developed a pH-responsive doxorubicin-loaded silica-polymethacrylic acid nano-gel via RAFT polymerization technique for the treatment of breast cancer [ ].",
"Click Chemistry Cross-linking polymerization technique and ortho ester diacrylamide [ ].",
"Photo-induced cross-linking was used in the development of docetaxel lipid-coated nano-gel [ , ].",
"In this process, polymers are first synthesized, followed by the cross-linking of the polymeric molecular chains to form nano-gels. This approach is particularly appropriate for creating nano-gels from natural polymers [ ]. The approach can be one of several different forms, including precipitation/cross-linking, emulsification/cross-linking, self-assembly/cross-linking, and micro-template forming/cross-linking, depending on the mechanism of nano-gel formation. Since the feature of the 3D network structure of nano-gels allows them to be carried with both hydrophilic and hydrophobic chemicals, nano-gels offer a platform for drug co-delivery. The study reported that phase-transition temperature emulsification was used to load doxorubicin and glycyrrhizic acid into alginate-based nano-gels, demonstrating synergistic anti-neoplastic effects mediated by both components of nano-gels in addition to their ability to target hepatocellular carcinoma [ ]. The nano-curcumin and Sulph loaded ethosomal nano-gel were prepared using a combination of both thin-film hydration and phase transition temperature process [ ].",
"Several pathogenic variables.",
"Vesicle size, size distribution, zeta potential, and morphology of diluted nano-gel are analyzed by zetasizer and Transmission or Scanning electron microscope, respectively. Kriti et al. and globule size also observed well defined sealed, lamellar, spherical structure of brucine-loaded trans-liposomal nano-gel with uniform size distribution via Zetasizer instrument and TEM using the dynamic light scattering approach. The transmission electron micrograph also indicated the absence of crystalline brucine, confirming the complete entrapment of brucine inside the vesicular architecture [ ].",
"The nano-gels are diluted to get the required concentration using a suitable solvent, and the absorbance is measured at spectroscopy according to the monograph; therefore, the following formulas were used for the determination of entrapment efficiency and drug content.",
"Ganesh et al. and pH, consistency as the property of nano-gel may alter due to physical changes such as pH. Both nano-gels are converted to pellet form via a hydraulic pelletizer; therefore, the dry weight through a dialysis membrane at 37 ± 0.5 °C. A definite amount of nano-gel is placed on the Franz diffusion cell after being transferred to the cellophane membrane, and to keep and ensure the initial consistent volume, a specific volume of aliquots is taken out at intervals and replaced with an equal volume of fresh phosphate buffer. Thereafter the samples are examined using the specific spectroscopic technique as per the monograph [ ]. The release kinetics modeling is done from cumulative percent release, whereas less than 30% of curcumin released at pH 7.4 buffer solution favoring tumor site-specific drug delivery [ ]. In vitro drug release in open-sink conditions demonstrated a sustained daily release of 7–10% of loaded curcumin with a zero-order kinetics in PBS at 25 °C. Very sustained curcumin release was observed at pH 7.4 and 25 °C with the first-order kinetics of the daily 7–10% drug release [ ]. A consistent release over an extended period was also observed to achieve a constant therapeutic benefit via controlling curcumin release rate from the multiple layer-by-layer also reported that HPMC-based quercetin of surface area and 7.5 mL of volume operating in continuous stirring mode, and a definite amount of formulation is placed on top of it. For 24 h, the receptor media was maintained at a constant temperature of 37 ± 0.5 °C and a constant mixing speed in terms of rpm. To promote skin hydration, the donor compartment and receiver compartment solution are equilibrated for one hour. A specific quantity of aliquot is removed from the receiver compartment and replaced with fresh PBS at the designated times and therefore analyzed via spectroscopic techniques as per the monograph [ ]. Studies showed significant of skin and time for the epidermis and dermis and assess T_(skinmax), C_(skinmax), AUC murine melanoma cell lines value have been effectively developed and assessed [ ]. Hormone therapies are effective for tumors linked to hormones [ ] but several hormonal therapies have been linked to elevated risk factors for diabetes mellitus and thrombosis [ ]. Nano-gels designed for targeted medication delivery in these cancer types are not linked to such risk factors. The most prevalent type of cancer in people is skin cancer.",
"“Skin cancer” refers to a variety of medical conditions that develop from distinct epidermal and dermal cells. Skin cancer has been successfully treated with loaded nano-gels of chitin-polymerized curcumin [ ]. The therapeutic effectiveness of the B16-F10 melanoma tumor was improved by a thermo-sensitive nano-hydrogel co-loaded with DOX, IL-2, and IFN-γ, which boosted tumor cell death and enhanced replication of CD3+/CD4+ and CD3+/CD8+ T cells [ ]. Drugs having high molecular weight have been formulated as nano-gels to enhance their solubility. For instance, tacrolimus, an immune-suppressive drug, was loaded in polyglycerol polymerized thermo-sensitive topical nano-gel and found to be improved adsorption of the drug through the layers of skin, attributing to the elevated body temperature for inflammation resulting in remarkable anti-proliferative activity [ ]. pH-responsive biodegradable 5-fluorouracil-loaded chitosan nano-gel was developed to treat melanoma in the mild acidic cancer micro-environment, effectively preserving the integrity of the skin layer in comparison with other traditional melanoma formulations [ ]. Transdermal curcumin nano-gels were developed to improve the solubility, transdermal permeability, and significant release of curcumin with lower toxicity attributed to their physicochemical characteristics when compared to traditional curcumin formulations [ ]. In order to create hydrophilic and thermo-responsive three-dimensional crosslinked nano-gels that can improve the penetration of both smaller and larger molecules through the squamous cells and aggregate within the hair follicles, dendrimers made of dendritic polyglycerol, providing a unique strategy against skin melanoma [ ]. A chemo-preventive study revealed that the average integer of UVB-inducing tumor, tumor volume was less in a remarkable manner in the quercetin-titanium dioxide nano-gel treated animals with improved quercetin deposition on the skin via down-regulating COX-2, EP3, EP4, PCNA, and cyclin D1 expressions [ ]. Therefore, for applications in targeted medication delivery, diagnostics, bio-sensing, and the separation of biological constituents, nano-gels have gained significant research interest.",
"Due to its distinctive features, nano-gel is increasingly being recognized as significant material for a variety of applications. Nano-gels can be used in different branches of science like drug delivery, tissue engineering, cosmetics, etc. Patent search with keywords “Nano-gel” and “Nano-gel” + “Skin Cancer” in the title, abstract, and claim showed 1238 and 9 patent results, respectively. The patent export data of nano-gel indicate that in recent years the number of patents increasing drastically to more than 100 per year with application fields like cellular, ocular, dental, and skin delivery of therapeutics and biologicals. A new class of research includes 3D-printed polymeric nano-gel particles. Out of 1238 patents on nano-gel, around 500 were active, and 400 were pending status; the United States of America with the highest number of 406 applications, followed by China with 332. C lists the major inventor in this field, and D shows that to date, 253 patents have been granted and 922 patent applications.",
"The possible development of nano-gels holds out considerable promise and provides researchers with new chances for medication delivery against a wide range of diseases and ailments. We can achieve optimal drug loading in the nano-gels by modifying the nano-gel system and precisely adjusting its composition, such as polymer type, molecular weight, and cross-linking density. In addition, other functional components like imaging probes and targeting moieties can be easily bonded onto nano-gels to investigate their potential for tailored therapeutic effects. Because of their multi-functionality, 3-dimensional polymer construction, and stimuli-responsive qualities, the ideal nano-sized properties of these agents would make nano-gels very appealing for topical targeted cancer therapy with minimal toxicity burden on patients. Nano-gels have the potential to open the door to effective target medication delivery to tissues and cancerous cells. Many factors, including those relating to patients and drugs, interact during cancer chemotherapy. Overall, in vitro and in vivo stability of dosage forms is crucial to ensure that it reaches the target site undamaged. When administered intravenously, which is the primary method of delivery for most cancer medications, nano-gels have shown to be a very stable dosage form that can deliver the required payload to malignant areas. As biocompatible biomimetic hydrogels are predicted to avoid the reticuloendothelial system and change the nuclear phagocytic system, they are likely to play a substantial impact on intracellular drug carriers resulting in a prolonged in vivo circulation period. Hence, drug delivery investigators must concentrate on these new kinds of nano-gels while also utilizing biocompatible, stable, and biodegradable natural polymers. The usage of polymer hybrids, or molecular blends made of a combination of synthetic and natural polymers, is another feature of nano-gels that will catch the interest of formulation scientists in the ensuing 10 years. Natural polymers would have a beneficial impact on biocompatibility and biodegradability, while synthetic polymers would offer more functionality. Natural polymers would provide an excellent candidate for implant delivery systems for anticancer medications because they do not produce hazardous breakdown products, in contrast to some synthetic polymers. When nano-gels are implanted into malignant regions, drug release will take place as expected owing to the engineering techniques used during formulation. This technique of delivery will significantly lessen off-target toxicities linked to the systemic distribution of various anticancer medicines by reducing drug migration to undesirable regions. The potential for one of the most significant breakthroughs in targeted cancer therapy has been expanded owing to nano-gel formulations of anticancer medications. Future applications of nano-gels in targeted cancer therapy have shown considerable promise in preliminary studies. For nano-gel formulations, there is a need to standardize procedures with a good manufacturing practice manual. In order to establish the safety profile of nano-gels and further our understanding of them, it is crucial to scale up research on nano-gels for targeted cancer therapy. The potential for using nano-gels as a target delivery method for anticancer medications is still quite great, and emerging pharma companies are anticipated to take advantage of this potential to improve the translational research of these medications."
] |
PMC10369066
|
Frontiers in Immunology
|
Gut colonization with an obesity-associated enteropathogenic microbe modulates the premetastatic niches to promote breast cancer lung and liver metastasis
|
12-07-2023
|
Introduction Obesity, an independent risk factor for breast cancer growth and metastatic progression, is also closely intertwined with gut dysbiosis; and both obese state and dysbiosis promote each other. Enteric abundance of Bacteroides fragilis is strongly linked with obesity, and we recently discovered the presence of B. fragilis in malignant breast cancer. Given that enterotoxigenic B. fragilis or ETBF, which secretes B. fragilis toxin (BFT), has been identified as a procarcinogenic microbe in breast cancer, it is necessary to examine its impact on distant metastasis and underlying systemic and localized alterations promoting metastatic progression of breast cancer. Methods We used syngeneic mammary intraductal (MIND) model harboring gut colonization with ETBF to query distant metastasis of breast cancer cells. Alterations in the immune network and cytokines/chemokines in the tumor microenvironment and distant metastatic sites were examined using flow cytometry, immunohistochemistry, and multiplex arrays. Results ETBF infection initiates a systemic inflammation aiding in the establishment of the premetastatic niche formation in vital organs via increased proinflammatory and protumorigenic cytokines like IL17A, IL17E, IL27p28, IL17A/F, IL6, and IL10 in addition to creating a prometastatic immunosuppressive environment in the liver and lungs rich in myeloid cells, macrophages, and T regulatory cells. It induces remodeling of the tumor microenvironment via immune cell and stroma infiltration, increased vasculogenesis, and an EMT-like response, thereby encouraging early metastatic dissemination ready to colonize the conducive environment in liver and lungs of the breast tumor-bearing mice. Discussion In this study, we show that enteric ETBF infection concomitantly induces systemic inflammation, reshapes the tumor immune microenvironment, and creates conducive metastatic niches to potentiate early dissemination and seeding of metastases to liver and lung tissues in agreement with the “seed and soil hypothesis.” Our results also support the ETBF-induced “parallel model” of metastasis that advocates for an early dissemination of tumor cells that form metastatic lesions independent of the primary tumor load.
|
[
"The impact of obesity on breast cancer can be appreciated by the fact that a 5-unit increase in body mass index. Adiposity and altered body fat composition can significantly influence breast cancer outcomes through an upsurge of proinflammatory cytokines and immune modulation. Likewise, dysbiotic gut microbiota can also influence breast cancer via several means including small metabolite-induced oncogenic signaling, systemic inflammation, and altered hormone regulation. Accordingly, several studies and clinical trials have implied the connection between obesity-induced dysbiosis and poor breast cancer outcomes, although the involvement of specific microbes is currently unclear.",
"It has been estimated that 13% of global cancer burden can be attributed to microbial infections. Of the 500–1,000 members of the microbiota and ~10^(12) known microbes on earth, only 10 have been characterized as Group I human carcinogens. While there is no dearth of data demonstrating the influence of microbiota in causation and therapeutic outcomes in colorectal and pancreatic cancers, the research in breast cancer is in its infancy. The insufficiency can be attributed to the fact that the breast has been considered a sterile organ until recently. Recent studies confirm the presence of a distinct breast microbiota that is clearly distinguishable between healthy and cancerous breast tissue. In fact, breast tumors are found to be the richest and most biodiverse among the nine tumor types examined, and the tumor-specific microbes reside within tumor as well as immune cells in a cell wall-deficient intracellular state. Translocation of oral microbes via the bloodstream into breast cancers has been confirmed. Also, distinct differences in gut microbiota have been observed between breast cancer patients and healthy controls, suggesting an association with breast cancer initiation and progression. Interestingly, tumor-resident intratumoral bacteria may drive metastatic colonization of breast cancer by inducing cytoskeletal reorganization in circulating tumor cells, thereby enhancing resistance to mechanical stress in the circulation. Microbes are enzyme factories, and microbiota-derived metabolites, such as Lipopolysaccharide. Moreover, bacterial quorum-sensing molecules have also been shown to enhance proliferation and potentiate angiogenesis and invasion of breast cancer cells. Dysbiosis also influences metabolism and bioavailability of drugs, therefore regulating therapy response. A spontaneous mammary tumorigenesis model infected with Helicobacter hepaticus yields more aggressive multifocal mammary tumors with significantly higher accumulation of neutrophils around the periphery of the tumors and in the stroma, and interestingly, these protumor effects are inhibited by the elimination of neutrophils following antibody treatment. It seems that the effects of microbiota and its metabolites on breast cancers are mediated at least partially via the immune system, as the breast microbiota correlates with the immunological signatures of breast cancer and the extent and expression of tumor-infiltrating lymphocytes. It is intriguing how microbes can influence the tumor immune microenvironment and influence tumor progression.",
"Drawing connections between obesity, microbiota, and breast cancer, increased abundance of Firmicutes and decreased levels of Bacteroidetes have been shown in the obese state as well as in breast cancer versus normal breasts and malignant breast cancer versus benign breast disease. Overall, many microbial families and species enriched in the obese state are similar to those observed in breast cancer samples compared to normal breasts, suggesting a microbial link between obesity, dysbiosis, and breast cancer risk. Dysbiosis leads to increased gut permeability resulting in elevated circulating LPS levels causing inflammation and insulin resistance. Systemic LPS stimulates Adipocyte fatty acid binding protein. Microbiota is also known to regulate the gut endocannabinoid system that can potentially stimulate an obese phenotype. Bacteroides fragilis , a common gut colonizer, has been associated with childhood and adolescent obesity. Sun et al. demonstrated that B. fragilis colonization in high-fat diet-fed mice led to more severe metabolic dysfunction and hyperglycemia mediated by increased bile acid glycoursodeoxycholic acid. A decrease in obesity parameters including BMI, fat mass, blood glucose, blood lipid, and hepatic function is associated with a decrease in the abundance of B. fragilis in the gut. Using a stringent constrained linear regression analysis, Shen et al. demonstrated the association of obesity with intestinal B. fragilis abundance in perimenopausal and postmenopausal women. B. fragilis accelerates obesity, in part, by suppressing acetic acid levels; acetates fuel the growth of health-associated microbes responsible for producing propionate and butyrate that maintain the integrity of the gut mucosa. These studies have established a strong link between the enteric abundance of B. fragilis and obesity.",
"Most interestingly, we recently discovered that the female breast is inhabited by B. fragilis , which is more abundant in cancerous compared to normal breast tissue. Our recent study has shown that enteric as well as mammary duct colonization with enterotoxigenic B. fragilis . In the present study, we aim to decipher the impact of enteric ETBF infection on distant metastasis of breast cancer cells, specifically asking. For immunohistochemistry, rabbit monoclonal anti-E-cadherin, anti-cMyc, anti-Notch1, anti-NICD, anti-Oct4, anti-Nanog, anti-KLF4, and anti-Ki67 were purchased from Cell Signaling Technology, Beverly, MA, USA. Anti-β-catenin, anti-CD31, anti-Jagged1 antibodies were purchased from Santa Cruz Biotechnology, Santa Cruz, CA, USA. IHC-specific rabbit monoclonal cMyc was purchased from Abcam, Cambridge, MA, USA. Mouse monoclonal β-actin was purchased from Sigma-Aldrich, St. Louis, MO, USA. Anti-IL6 and anti-TNFα antibodies for ELISA were obtained from Santa Cruz Biotechnology, Santa Cruz, CA, USA. For flow cytometry, anti-CD3, anti-CD4, anti-CD8, anti-CD45, anti-CD11c, anti-CD11b, anti-FOXP3, anti-PD-L1, anti-F4/80, anti-granzyme B, anti-IFNγ, and anti-TNFα antibodies were purchased from BD Biosciences, San Jose, CA. Horseradish peroxidase-conjugated goat anti-rabbit IgG, goat anti-mouse IgG, and donkey anti-goat IgG were purchased from Sigma-Aldrich, St. Louis, MO, USA. Chemiluminescent peroxidase substrate and 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide.",
"Twice parous BALB/c mice were procured from Charles River, maintained in-house, and were given antibiotic cocktail.",
"For flow cytometric analysis of immune infiltrates, spleen, tumors, liver, and lungs were excised and immediately collected in harvest media and the Aperio Toolbox. Here, to examine the impact of ETBF on distant metastasis of breast cancer, we used the 4T1 breast cancer syngeneic mouse model. Using a mammary intraductal. To determine the mode of metastatic dissemination, mice were sacrificed at three different time points: week 1, week 2, and week 4 post-tumor cell implantation. In addition to accelerated tumor growth. Marked increase in lung and liver metastatic lesions were observed in the ETBF group compared to controls. Furthermore, we conducted in vivo whole-body bioluminescent imaging, ex situ imaging of lungs and liver, ex situ metastatic colony formation assay, and histological analysis to validate metastatic seeding. Whole-body bioluminescent imaging showed detectable spreading of the primary breast tumor to distant visceral organs, most likely lungs and liver in addition to bones, with the ETBF group exhibiting a higher metastatic spread. Interestingly, ex situ imaging of liver and lungs revealed no metastatic seeding in lungs and liver at weeks 1 and 2 post-tumor cell implantation in the control group, while seeding was evident from the luminescent signals starting at week 1 post-tumor cell implantation in ETBF-colonized mice, confirming significantly more and earlier metastatic dissemination and seeding in ETBF-infected mice. Similarly, in ex vivo metastatic cell colony formation assay, liver and lung explants from tumor-bearing mice were digested and seeded in the presence of 6-thioguanine. While no metastatic cell colonies formed in liver digests at week 1 post-tumor cell implantation, a significantly higher number of metastatic cell colonies formed at week 2 and 4 post-tumor cell implantation in the ETBF group compared to the control group. Metastatic cell colonies formed in lung digests in the ETBF group were considerably more in number and size in comparison to controls, starting at week 1 post-tumor cell implantation, suggesting that metastatic seeding in ETBF gut colonized mice started immediately after tumor implant regardless of tumor growth. In histological sections, although micrometastasis could not be detected at weeks 1 and 2 post-tumor cell implantation, widespread inflammation and neutrophil infiltration were evident in lungs and liver of ETBF-infected mice, while large metastases were evident at week 4 post-tumor cell implantation. It, therefore, suggested that the gut colonization with ETBF induced systemic inflammation in the distant organs, i.e., lungs and liver, which supported metastatic seeding in these mice. We also examined the tumors of respective groups by IHC. In line with tumor progression, Ki67 expression was notably higher in the ETBF-colonized group, as was the expression of cMyc in the nuclei of tumor cells. While β-catenin was completely membrane-bound or cytoplasmic in control tumors, it was mostly localized in nuclei in the ETBF-infected group. Notch1 expression was significantly denser in the tumors of ETBF-infected mice, as was the expression of cleaved-Notch1 in the nuclei. Vascular endothelial growth factor receptor 2. Collectively, these results show that gut colonization with ETBF accelerates breast cancer metastasis.",
"Since the pattern of metastatic dissemination was indicative of a more efficient seeding in ETBF-infected mice, we hypothesized that ETBF manipulated the premetastatic niche in the liver and lungs, supporting the establishment of secondary tumors in these organs. To test our hypothesis, non-tumor-bearing mice were infected with ETBF by oral gavage and sacrificed at day 5 post-infection, when the bacteria had stably colonized the gut. Serum and vital organs were analyzed to uncover the ETBF-induced changes. The serum was analyzed for 29 chemokines including proinflammatory chemokines, Th17 response chemokines, and cytokines using a multiplexed ELISA. While most of the circulating cytokines did not vary significantly between the sham control and ETBF-infected groups, some interesting patterns were apparent. Of the nine Th17 responsive chemokines, IL17A and IL17E were found to be significantly upregulated in the serum of ETBF-infected mice. Out of the six members of the IL17 family of cytokines, IL17A, IL17B, and IL17E have been found to aid in tumor growth, angiogenesis, metastasis, and chemoresistance. Of all the cytokines, a significant upsurge was observed only in IL15 and IL27p28. While IL15 has been shown to be associated with better prognosis in breast cancer, IL27p28 has been shown to be involved in growth and metastasis of triple-negative breast cancers and has been frequently detected in breast cancer patients but undetectable in normal women. With a significant increase in IL17A, IL17E, and IL27p28 levels, the circulatory cytokine milieu thus appears to be favorable for breast cancer progression.",
"Next, we investigated the effect of ETBF enteric infection on systemic immune modulation. As a surrogate for systemic immune modulation, spleens were isolated from mice harboring gut ETBF infection for 5 days and analyzed by flow cytometry. In the spleen, total CD4^(+) T-cell population remained fairly unchanged along with a static population of CD4^(+)Foxp3^(+) T regulatory cells and CD8^(+) T cells. However, there was a significant reduction in CD11c^(+) dendritic cells in the ETBF group, suggesting a systemic inflammatory response to ETBF infection. There was also a statistically significant decline in the proportion of myeloid cells. Stimulated CD8^(+) T cells trended toward increased granzyme B and IFNγ in the ETBF group, but the difference was not statistically significant, suggesting that while the CD4^(+) T cells were activated in ETBF-infected animals compared to the controls, the status of CD8^(+) T cells remained fairly unchanged.",
"We then sought to find out how ETBF enteric infection shaped the immune microenvironment of liver and lungs by flow cytometry. At day 5 post-ETBF infection, while lungs showed significantly higher accumulation of CD4^(+) T cells, CD4^(+)Foxp3^(+) T cells, CD8^(+) T cells, CD11b^(+) myeloid cells, CD11b^(+)F4/80^(+) macrophages, and CD11c^(+) dendritic cells in the ETBF group compared to the sham control group, the liver showed higher accumulation of CD4^(+)Foxp3^(+) T regulatory cells in the ETBF-infected group. Histologic evaluation of liver and lungs from ETBF-infected mice showed interesting alterations in comparison to the sham control group. Histology of the liver showed acute-phase inflammation, microgranuloma, dead cells between neutrophils, clusters of neutrophils, hemorrhage, accumulated neutrophils, necrosis <24 h old, extramedullary hematopoiesis. In the lungs from ETBF-infected mice, neutrophils and B cells around bronchiole and pulmonary vein were observed. To closely follow the course of events, we also tested the serum from ETBF-infected, 086Mut-infected, and sham control 4T1 tumor-bearing mice at day 3 and 4 weeks post-tumor cell implantation for the levels of early-response cytokines, IL6 and TNFα. Both the cytokines showed consistent and significant upregulation from day 3 through week 4 post-tumor cell implantation in the ETBF group. These results clearly demonstrate that ETBF gut colonization induces a systemic inflammation and prepares the premetastatic niche for the breast cancer cells.",
"Metastasis is a complex and inefficient process involving the escape of cancer cells from the primary tumors, also known as “the seed” and its establishment in distant organs, as known as “the soil.” The evolution of a tumor from benign to metastatic state involves multiple molecular mechanisms. After establishing that ETBF enteric infection causes systemic inflammation and prepares the lungs and liver as the potential metastatic sites, we asked whether it also alters the tumor microenvironment. Hence, we investigated the tumor microenvironment in both the sham control and ETBF-infected groups. Confirming the impression from H&E staining, trichrome staining showed significant stroma infiltration and fibrosis in the tumors from ETBF-infected mice. Fibronectin expression was also significantly higher in the ETBF-infected group compared to tumors from the sham control group, along with higher CD31 expression showing more tumor angiogenesis. While E-cadherin expression seemed to be diminished, N-cadherin was marginally higher in the ETBF-infected group. Mesenchymal marker vimentin also showed a higher expression in tumors from ETBF-infected mice in comparison to those from the sham control. These results suggested that an EMT response in mammary tumors was elicited by ETBF gut infection. Next, we evaluated the immune landscape of the tumors by flow cytometry and immunohistochemistry. Immunoblot analyses showed a higher expression of Notch as well as EMT markers in ETBF tumors compared to that in the control group. Tumor-infiltrating lymphocytes were evaluated by flow cytometry. While CD11b^(+) myeloid cells, CD11b^(+)F4/80^(+) macrophages, and CD11c^(+) dendritic cells trended toward higher accumulation at week 1 post-tumor cell implantation in the ETBF group, CD11b^(+)F4/80^(+) macrophages and CD11c^(+) dendritic cells showed significantly higher accumulation in tumors from ETBF-infected mice at 4 weeks post-tumor implantation. Also, CD4^(+) T cells showed a notable increase. IHC was performed to visualize the spatial organization of immune infiltrates. Macrophages and their precursors, monocytes, marked by IBA1 showed higher tumor infiltration both at week 1 and 4 post-tumor cell implantation in the ETBF group, while higher IBA1-positive cells were also observed in adjacent normal breast of ETBF-infected mice. In contrast, CD8α^(+) cell accumulation within tumor and adjacent normal breast was marginally different in ETBF-infected mice. As a surrogate for systemic immune modulation, spleens from tumor-bearing mice at 1 week and 4 weeks post-tumor cell implantation in the ETBF group were resected and analyzed by flow cytometry. Immune phenotyping showed a modulation in the proportion of CD8^(+) T cell and CD11b^(+)F4/80^(+) macrophage populations at week 1 post-tumor cell implantation ETBF group. Alterations were also observed at week 4 post-tumor cell implantation ETBF group, but only CD11b^(+)F4/80^(+) macrophages achieved statistical significance. On interrogating the serum cytokines in these tumor-bearing mice, we observed a significant upregulation of IL5 and IL27p28 in the ETBF group, similar to the non-tumor-bearing mice, reiterating the protumorigenic role of ETBF in this breast cancer model. Unlike non-tumor-bearing mice, there was no significant alteration in the levels of IL17A and IL17E between the two groups of tumor-bearing mice, but there was a significant increase in IL17A/F, heterodimer of IL17A and IL17F, which are known to work in concert to enhance breast cancer aggressiveness. Additionally, there was a significant upregulation of prometastatic cytokines IL10, IL6, and MCP1 in the circulation in ETBF-infected mice harboring 4T1 tumors in comparison to sham control mice with 4T1 tumors. Together, these results show that ETBF gut infection leads to modulation of the tumor microenvironment.",
"To further investigate the mechanism of distant metastasis aggravated by ETBF enteric infection, the organs were analyzed by immunohistochemistry and flow cytometry. Metastatic lesions in the lungs and liver of ETBF-infected mice were significantly larger compared to those of the sham control group. In the liver sections, most of the metastases and small clusters of immune cells stained strongly positive for Ki67, indicating that the cells in the metastatic lesions were proliferating in the ETBF group. Metastatic lesions were densely surrounded by CD3^(+) immune cells in the periphery. While the primary tumors expressed little N-cadherin, the metastases expressed detectable levels of both N-cadherin and E-cadherin in the ETBF-infected mice. Interestingly, similar to primary tumors, the metastatic liver in the ETBF-infected group exhibited very high fibronectin expression. The liver of ETBF-infected 4T1 tumor-bearing mice also expressed higher levels of CD31 and VEGFR2, suggesting profuse angiogenesis. While IHC did not show any difference in cytotoxic CD8α^(+) T-cell accumulation in the liver, significantly higher levels of monocytes and macrophages were detected in the liver of ETBF-infected mice by IBA1-specific IHC. By flow cytometry, statistically significant upregulation was observed only in the levels of CD11b^(+)F4/80^(+) macrophages and CD11b^(+) myeloid cells at week 1. Scrutinizing the lung metastatic lesions, we found that most of the lungs in the ETBF gut colonized mice were filled with metastatic cancer cells and immune infiltrates, majorly neutrophils, which were far less in the sham control group. One hundred percent of the metastases and surrounding neutrophils stained strongly positive for Ki67. In contrast, not only were the metastatic lesions smaller in the control group, they were not actively proliferating as well. While there was no difference in the density of CD3-positive cells in the lungs of the two groups, fibronectin level was lower in the lung metastases in the ETBF-infected group. Interestingly, both N-cadherin and E-cadherin levels were higher in the lung metastases in the ETBF-infected group. Mice harboring ETBF gut infection exhibited a higher expression of CD31 and VEGFR2 in the lung metastases that could support higher vasculogenesis to sustain proliferation of metastatic lesions. Flow cytometric analysis revealed significantly higher levels of CD8^(+) T cells and CD4^(+) T-cell infiltrates in lungs of 4-week ETBF-colonized mice, while other cell types did not vary significantly. IHC showed a significantly higher accumulation of IBA1-positive monocytes and macrophages and marginally lower accumulation of cytotoxic CD8α^(+) T cells in the lung metastases of ETBF-infected mice in comparison to those in sham control mice. These results unequivocally show that enteric infection with ETBF not only enhances early and efficient metastatic dissemination of cancer cells growing as primary tumors in mammary gland ducts but also causes systemic inflammation, modulates the tumor microenvironment, and primes potential metastatic niches to allow the development of metastatic lesions."
] |
PMC10785397
|
BMC Health Services Research
|
Causes and consequences of quack medicine in health care: a scoping review of global experience
|
11-01-2024
|
Background The field of health has been facing challenges with fraudulent practices and the prevalence of “quack medicine”. Many cases have given rise to this issue. Therefore, this study aims to comprehensively investigate and categorize the causes and consequences of quack medicine in the healthcare. Methods A scoping review, using the 5 stages of Arksey and O’Malley’s framework, was conducted to retrieve and analyze the literature. International databases including the PubMed, Scopus, Embase and Web of Science and also national Iranian databases were searched to find peer reviewed published literature in English and Persian languages. Grey literature was also included. Meta-Synthesis was applied to analyze the findings through an inductive approach. Results Out of 3794 initially identified studies, 30 were selected for this study. Based on the findings of this research, the causes of quackery in the health were divided into six categories: political, economic, socio-cultural, technical-organizational, legal and psychological. Additionally, the consequences of this issue were classified into three categories: health, economic and social. Economic and social factors were found to have a more significant impact on the prevalence of quackery in the health sector. Legal and technical-organizational factors played a crucial role in facilitating fraudulent practices, resulting in severe health consequences. Conclusion It is evident that governing bodies and health systems must prioritize addressing economic and social factors in combating quackery in the health sector. Special attention should be paid to the issue of cultural development and community education to strengthen the mechanisms that lead to the society access to standard affordable services. Efforts should be made also to improve the efficiency of legislation, implementation and evaluation systems to effectively tackle this issue.
|
[
"Issues such as quackery and charlatanism have long been a concern for human civilizations and communities since the development of health service delivery structures and processes. While the forms and severity of these issues may vary across nations, it can be argued that all health systems are susceptible to some level of quackery [ ]. In the health system, particularly in developing countries, a phenomenon known as “Quack Medicine” has been a persistent problem, causing harm in various branches of health care services. Quackery refers to unproven or fraudulent medical practices that there is no scientifically plausible rationale behind them. Furthermore, someone who does not have professional qualification, formal registration from a legitimated institution, or required knowledge of a particular branch of medicine but practices in the field of medicine, is called quack [ – ]. So quack medicine refers to the fraudulent practice of quacks in the medical field claiming to possess the ability and experience to diagnose and treat diseases, and pretending that the medicine or treatment they provide are effective, generally for personal and financial gain [ ]. A study from India defines the following individuals as quacks as well: practitioners of local types of medicine such as Indian Medicine Ayurvedic and Homeopathy who practice modern practice although they are not allowed to do so and those who engage in any type of medicine which have not been recognized by law [ ]. Other examples of this phenomenon include billing for services not provided, substituting substandard products for standard ones, taking unnecessary steps to get more reimbursement, and prescribing unnecessary medications for financial gain instead of addressing medical needs [ ].",
"In a historical survey conducted by the American Medical Ethics Association in 2000, it was found that in 1775, only 400 out of every 3,000 individuals claiming to be doctors had legitimate medical degrees from accredited universities and schools. Also, the vast geographical size of this country and the dispersion of experienced doctors led to the public seeking to refer to quack doctors. In the 19th and 20th centuries, these charlatans utilized pseudo-scientific terms and advanced equipment and technologies to deceive people, blurring the line between a legitimate doctor and a quack [ ]. In 2020, the Independent newspaper reported on this issue in Bangladesh, revealing that 75% of quack doctors were prescribing inappropriate medications to patients, with 7% prescribing drugs that were completely harmful and dangerous [ ].",
"The seriousness of this problem led the World Health Organization What are the main reasons for the prevalence of quack medicine in the healthcare? and International Transparency Organization. National Iranian databases were also searched for relevant literature in Persian. These databases included SID, Magiran and IranDoc. Furthermore, reference lists of selected documents were also scanned for additional relevant articles. The details of all the selected studies were saved in EndNote X7 software, which can be used to find duplication in extracted studies.",
"A total of 3794 documents were retrieved from the initial search, of which 2477 were removed due to duplication. Then two of authors reviewed the title of 1317 remained articles and 852 documents further removed as they were not found to address the topic directly. In the next step, after the first screening, the entire texts of 465 articles were checked based on the exclusion criteria established for the research, and 435 were rejected. Eventually 30 papers were included for the purpose of the study, and the causes and effects of charlatanism in the field of health were used to explain the results.",
"The process of study selection is shown in Fig. . The similar information was extracted for grey literature. In addition, the frequency of studies included in the research by date, type and design is shown in Table .",
"Meta-Synthesis was applied to analyze the findings through an inductive method. The full text of all finalized documents were studied carefully. Findings of the studies, the reasons and the consequences of quack medicine, were summarized in two separate tables. These summaries were then grouped into broader categories based on the similarities between them. During the final phase, the research team engaged in a thorough discussion regarding the initial categorization of reasons and consequences. Amendments were made as needed including paraphrasing headings, modifying classifications or transferring sub-categories. This iterative process continued until consensus was achieved. Tables and show the final categorization for factors contributing to quack medicine and its impacts on healthcare respectively.",
"",
"",
"Among the retrieved documents, the highest number of articles published within the period of 2011–2022 (13 out of 30). The number of included studies by type is 5 original studies, 5 review studies and 20 studies from other types. Furthermore, almost half of the selected studies were qualitative, followed by five review, three commentary, one cross-sectional and seven studies had no specific design. The frequency percentage of studies according to the mentioned characteristics is shown in the Table .",
""
] |
PMC10350961
|
The Journal of Physical Chemistry Letters
|
Bond Polarizability as a Probe of Local Crystal Fields
in Hybrid Lead-Halide Perovskites
|
05-07-2023
|
A rotating organic
cation and a dynamically disordered soft inorganic
cage are the hallmark features of organic-inorganic lead-halide perovskites.
Understanding the interplay between these two subsystems is a challenging
problem, but it is this coupling that is widely conjectured to be
responsible for the unique behavior of photocarriers in these materials.
In this work, we use the fact that the polarizability of the organic
cation strongly depends on the ambient electrostatic environment to
put the molecule forward as a sensitive probe of the local crystal
fields inside the lattice cell. We measure the average polarizability
of the C/N–H bond stretching mode by means of infrared spectroscopy,
which allows us to deduce the character of the motion of the cation
molecule, find the magnitude of the local crystal field, and place
an estimate on the strength of the hydrogen bond between the hydrogen
and halide atoms. Our results pave the way for understanding electric
fields in lead-halide perovskites using infrared bond spectroscopy.
|
[
"The efficiency\nof hybrid organic-inorganic\nlead-halide perovskite. The main reason for this choice is\nthat these modes are by far the strongest in terms of IR-intensity.^(17 , 30 , 41) Elementary counting of the degrees\nof freedom reveals. In C we show how the. To relate it to the polarizability\n⟨ α^(H) ⟩ measured in experiment, α _(ij)^(H) must be averaged over all\nspatial orientations of the bond and different configurations of . For MAPbBr_(3), which is cubic\n(on average) at room temperature, one can write):where the index H _(k) runs over the six longitudinal C(N)–H\nstretching\nmodes for further details.",
"The quantities ρ and α^(H) in can be determined theoretically from the\nliterature and DFT calculations\nfor different scenarios, such as the presence of defects. relates these theoretical\ncalculations to the measured average polarizability, ⟨ α^(H) ⟩, allowing one to investigate\nmicroscopic properties of HOIPs using molecules as experimental probes.",
"To illustrate the formal discussion above, we proceed with measuring\nthe average polarizability ⟨ α ^(H)⟩ for a bulk single crystal sample of MAPbBr_(3) in the cubic phase. For this purpose, we measure the group\nrefractive index n _(g)( ω ) in the mid-infrared frequency range relevant for vibrational degrees\nof freedom of methylammonium.^(17) The advantage\nof the group index for probing molecular polarizability, which in\ngeneral provides much weaker contribution to the refractive index\nas compared to the electronic one, lies in the fact that n _(g)( ω ) features stronger divergence\nnear resonances and is therefore more sensitive as compared to the\nphase index n _(ph)( ω ). Indeed, n _(g)( ω )/ n _(ph)( ω ) ≈\nΩ/( ω – Ω) near the resonance\nfrequency Ω.",
"To measure the group\nrefractive index in a direct manner, we develop\na time-resolved setup depicted in A. The setup utilizes two samples of single-crystal\nMAPbBr_(3): the actual test sample in which n _(g) is measured and a probe sample for a broadband\nultrafast detection of mid-infrared pulses by means of the optical\nKerr effect. By measuring the time of arrival of the mid-IR\npulse at the probe sample with and without the test sample, one obtains\nthe delay δt introduced by the test sample.\nThe time delay δt for the mid-IR pulse due\nto traveling through the perovskite sample of thickness d = 1.6 mm, is , where n _(g) and n _(g)^(air) ≈ 1 are the group refractive indices of MAPbBr_(3) and air, respectively; c is the speed of light.",
"The ultrafast optical Kerr effect in the probe sample is detected\nby the standard time-resolved pump-probe method in a balanced detection\nscheme). An\nexample of a time-resolved transient Kerr response for λ = 5 μm mid-IR pump with and without the test sample is\ndepicted in B. The difference in arrival time of the mid-IR pulse at the probe\nsample δt is measured as the distance between\nthe two peak positions; the inset shows the FTIR of the pump pulse\n(see ref). Performing\nsimilar measurements for other mid-IR wavelength values, one can extract\nthe perovskite group index n _(g)( ω ) = n _(g)^(air) + cδt / d over a broad range of wavelengths.",
"The measured\ngroup refractive index dispersion n _(g)( ω ) of bulk single crystal MAPbBr_(3) as a\nfunction of the photon energy, ℏω , is\ndisplayed in . Here, we identify two regions of absorption, one in the\nlow energy region at ∼0.17 eV) in\nthe region outside the immediate vicinity of the absorption band corresponding\nto the C(N)–H stretching modes justifies our assumption that\nthese modes can be approximated as isolated from the nearby C(N)–H\nbending modes.",
"To extract the molecular contribution to the refractive index,\nwe need to subtract the electronic contribution from the measured\ninfrared n _(g)( ω ).\n(Note that the electronic contribution to the refractive index is\ntypically the dominant one, since electrons are much lighter than\nions. Only close to a molecular resonance does the molecular contribution\nbecome important.) To this end, we use our previous measurements of\nthe phase index in the visible and near-IR region.^(45) In this high frequency range near the bulk band transition\nfrequency, ℏω ∼ Δ_(gap) and the refractive index is determined by the electronic polarizability\nof the lead-halide cage. By first fitting the high-frequency phase\nindex from ref with a Sellmeier expression, and then calculating the group index\nfrom it and extrapolating the result to the mid-IR frequencies, one\ncan obtain the electronic part n _(g,el)( ω ) of the total group refractive index n _(g)( ω ) coming from the crystal cage. n _(g,el)( ω ) in the mid-IR\nrange calculated this way is plotted as a light blue dashed line in providing an excellent\nfit to the data in the relevant frequency range away from the nearby\nabsorption band. The molecular part of the group index n _(g,mol) is found by subtracting the cage electronic contribution\nfrom the total refractive index: n _(g,mol)( ω ) = n _(g)( ω ) – n _(g,el)( ω )).",
"Once n _(g,mol)( ω ) is known, it is possible to calculate the polarizability\nof the\ngiven mode by fitting it to the classical resonance profile near the\nresonant frequency. We focus on the C(N)–H stretching modes\ncentered around ℏ Ω_(H) ≈ 0.37 eV–H bonds. However,\ndue to strong mass mismatch between H and C(N), the natural frequencies\nof these modes are very similar.^(17 , 30 , 41) If we assume that C and N are infinitely heavy compared\nto hydrogen, then each vibration of H along the C(N)–H bond\ncan be considered independent and decoupled from the rest. Within\nthis approximation.",
"To connect n _(g,mol)( ω ) to ⟨ α _(0)^(H)⟩, we account\nfor the screening effect due to the polarizable cage and write in\nthe vicinity of Ω_(H) for derivation),where is the electronic contribution\nof the phase\nrefractive index at Ω_(H), and ⟨ α _(0)^(H)⟩ is the average static( ω ) to the expression in . From the fit, we obtain ⟨ α _(0)^(H)⟩ ≈ and naively assume that the molecule\nrotations are uncorrelated with the inorganic cage. In terms of , this limit corresponds\nto , for which) the average polarizability\nremains unrenormalized even in the presence of strong crystal fields where α _(0)^(H)( E = 0) can be taken from C so that Å^(3). Since the discrepancy\nbetween this value and the experimental one above is beyond the error\nmargin of our approach, we can conclusively rule out uncorrelated\nmolecule-cage dynamics, in agreement with prior results.^(26 , 49 − 51) If, conversely, we fix the density matrix in in accordance with previous\nreports in the literature,^(28) then we arrive\nat the value for the local crystal field experienced by the N–H\nbond | E _(CF)| =). Therefore, to account for the relatively large\nvalue of E _(CF), we need to go beyond the\npoint-source approximation for the atoms in the inorganic cage. The\nlowest-order multipole moment would be the quadrupolar moment D of the bromine atom with the axis along Pb–Br–Pb.\nKnowing | E _(CF)| and the distance between\nH and Br one can estimate that D ∼ +1 eÅ^(2). Recalling now that a hydrogen bond can be defined as an\ninteraction between H and a multipole potential of a neighboring atom,^(52) we estimate it from the energy of the H–Br\nelectrostatic interaction eV). This value is in reasonable\nagreement with previous estimates^(50 , 53) of the energy\nof the H–Br hydrogen bond, illustrating that the proposed here\nmolecular probe can provide important insight into the existence of\nhydrogen bonding in HOIPs.^(54 , 55)",
"In conclusion,\nwe propose the semiautonomous A-site cations in\nHOIPs as a sensitive local probe for optical spectroscopy, which complements\nthe existing techniques such as NMR and NQR. To illustrate the formulated\ntheoretical framework, we have analyzed the average polarizability\nof the N–H stretching mode extracted by measuring the group\nrefractive index of a bulk single crystal sample of MAPbBr_(3) in the mid-IR wavelength range. Based on the analysis, we have ruled\nout the possibility of an uncorrelated motion of methylammonium cation\nin a PbBr cage and estimated local electric fields at the locus of\nthe C(N)–H bond. We also estimated the value of the quadrupole\nmoment for the Br atom, and the energy of the H–Br hydrogen\nbond. Our work proposes a new approach to the study of the complex\nbehavior of the dynamically disordered inorganic cage, which will\nprovide novel insight into fundamental properties of lead-halide perovskites.\nIn particular, being all-optical, our approach can be employed to\nstudy ultrafast transient behavior of lattice irregularities, for\nexample polaronic structures formed around photoexcitations. Since\nit is widely expected that the formation of such polarons underlies\nsome most important optoelectronic properties of lead halide perovskites,^(10) our results offer an approach to clarify some\nof the most pressing questions related to the solar energy harvesting\napplications of lead-halide perovskites."
] |
PMC10500542
|
Cureus
|
Hand Scrubbing and Donning of Sterile Surgical Gloves: An Observational Clinical Audit of Novice Dental Surgeons
|
15-08-2023
|
Background The most critical factors in the satisfactory recovery of a patient post-surgery are obedience to sterilization and aseptic protocol. Using aseptic principles, the standard hand scrubbing and gloving procedure prevents contamination of the surgical site and aids in infection control. Methods Eighty dental interns were observed during minor oral surgical procedures for hand scrubbing and donning sterile surgical gloves, following the steps and guidelines provided by World Health Organization (WHO). The dental interns were evaluated, and in order to enhance their understanding of hand scrubbing and donning surgical gloves, desensitization programs were conducted through lectures using PowerPoint presentations. After one week, the participants were observed and evaluated again. This program made the participants aware of asepsis and infection control in clinical practice. Results Prior to intervention, only 37.14% of young dental surgeons performed proper conventional hand hygiene practices. After the intervention, this percentage increased to 62.142%, indicating a significant improvement. Regarding the donning of sterile surgical gloves, 43.75% of participants followed the standard steps before the intervention. After the intervention, the percentage raised to 86.25% indicating substantial growth. Conclusion Observations before and after the evaluation demonstrated significant changes in the acceptance rates for the fundamental criteria of hand hygiene and donning sterile surgical gloves. Adhering to both procedures according to WHO guidelines will help to reduce the risk of infections and raise awareness about asepsis in the practice among young dental surgeons.
|
[
"Prevention of surgical site infections is critical for evaluating control mechanisms within healthcare systems and implementing the necessary changes. However, such monitoring can be costly, posing an enormous problem to healthcare systems around the world, particularly in impoverished countries [ ].",
"Putting on gloves before surgery and taking them off during surgery constitutes some of the most common ways for a surgeon to infect oneself and the disinfected operative area. There are two ways to depict donning sterile surgical gloves i.e., open and closed gloving technique. The scrub person's hands should remain inside the sleeves and not touch the cuffs when using the closed-glove technique. The scrubbing person's hands slip all through the sleeves and beyond the cuffs when using the open-glove technique. Previous research has shown that the interface between the glove cuff and the gown is where contamination occurs most frequently [ - ]. Scrubbing, barrier garments, gloving, drapes, and tool sterilization are all essential aseptic measures for maintaining the sterile field's integrity. However, due to the hurried nature of the operating room/IEC/2023/1071, this four-week clinical review was conducted at the Department of Oral and Maxillofacial Surgery's minor oral surgery room at Sharad Pawar Dental College, Wardha. The study included 80 young dental surgeons undergoing internship and having adequate knowledge about sterilization and asepsis, and hence the population was selected. To create the methodology, planning, and effects of this research, an in-depth review of the literature was executed.",
"Pre-evaluation",
"In the first week, all participants were monitored while scrubbing their hands and donning surgical gloves prior to minor oral surgery procedures. The observation was noted and compared to WHO standards for hand scrubbing and donning sterile surgical gloves. To assess all interns, we took the following evaluation criteria. The procedures outlined in the tables assess the effectiveness of young dental surgeons' hand hygiene and donning sterile surgical gloves. In Table for hand scrubbing, every 'yes' signifies one correct step followed and each 'no' indicates one incorrect step from an entire set of ten steps. Similarly in Table for donning sterile surgical gloves from a total of eight steps same criteria were applied. We calculated compliance with these 10 criteria for hand cleaning and eight criteria for donning sterile surgical gloves for each participant and totaled the outcomes of all those involved in each criterion individually. These percentages were mainly utilized to calculate the general compliance of all participants to each criterion.",
"The sensitization",
"Following the first week of gathering information and observation, everyone who participated was given a presentation. It comprises a demo video of the conventional hand scrubbing and surgical gloving approach according to WHO recommendations. Subsequently, third-year residents of the oral surgery department also gave an individual demonstration of performing each and every step of hand scrubbing and gloving in accordance with WHO guidelines in the minor oral surgical room to the participants. Subsequently, third-year residents of the oral surgery department also gave an individual demonstration in the minor oral surgical room to the participants. A pictorial guide for hand scrubbing was also displayed inside the minor oral surgical room.",
"Post-evaluation",
"After one week of intervention, all participants were inspected again for compliance with the hand scrubbing and standard surgical gloving criteria in the subsequent phase of the audit, i.e., the final week. Each correctly completed step received one mark, and all 10 stages for hand scrubbing and eight steps for donning sterile surgical gloves were examined free of constraints. Everyone was presented with a total score, and the average improvement was computed by putting all the compliance scores together. We calculated compliance with these 10 criteria for hand scrubbing and eight criteria for donning sterile surgical gloves for each participant and added the scores of all participants to each criterion independently. The overall conformance of all participants to each criterion was calculated using percentages.",
"Eighty young dental surgeons, 55 females and 25 males, were observed for the purpose of awareness and implementation of conventional hand hygiene skills, as well as their use of sterile surgical gloves. The cumulative percentages of compliance of all participants to each criterion separately for hand hygiene had the smallest difference of 20% because these processes were precisely followed by all participants. In addition, 30% of candidates disregarded criterion 3 for donning sterile surgical gloves: opening the outer package without touching it to the sterile surface and placing the inside packet on the sterile surface. The greatest rate of growth was shown in criteria 9, where 70% of participants gained knowledge to scrub their palms with their digits, with a 70% variance among pre-post-intervention. In the instance of hand hygiene, all participants accomplished 37.14% of the standard guidelines during pre-sensitized observation, however, 62.142% met them afterward the sensitization. The percentage of rise in before and after intervention, hand hygiene compliance rates remained exceptional at 30.002%. In the case of wearing sterile surgical gloves, interns met 43.75% of the demands during the pre-intervention inspection and 86.25% after the sensitization. The rate of increase in surgical glove compliance rates is impressive at 86.25%. After taking the feedback from the participants about the sensitization the maximum preferred was the individual demonstration as shown in. The result can be well depicted in the form of a bar chart given in. The bar chart displays pre-evaluation in blue color, post-evaluation in orange color and percentage improvement in grey color.",
"As in minor surgical procedures of oral surgery, while doing patients, two techniques are most important: hand hygiene and surgical gloving. Before we start a surgical procedure, we should follow all hand hygiene steps according to WHO guidelines. If bacteria and viruses enter the bloodstream through patients, it may cause serious infections like hepatitis, HIV, severe acute respiratory syndrome, etc. Following the aseptic technique is of utmost importance to prevent the spread of infection while doing minor procedures such as Exodontia, Arch bar placement, 3rd Molar surgery, etc. This surgical audit intends to evaluate the procedures like hand scrubbing and donning gloves in young dental surgeons in the Oral and Maxillofacial Surgery Department. In our study, the participants fulfilled Criteria 1, 4, and 6 in Table and Criteria 3 in Table . Before the intervention, the compliance rate at Lahore General Hospital was 70% and 55%, accordingly [ ]. According to a research report released in Nepal in 2022, the average compliance for criteria 4 and 5 is 89% [ ].",
"The most progress was shown by Criteria 9 in Table and Criteria 7 in Table which rose from 30% to 100% and 20% to 80%, respectively. Our participants showed better compliance rates by 100% in criteria 4, 7, 9, and 10 in Table and criteria 4 and 8 in Table respectively. However, in the study published by Biddhya and Bista, which was done in an operating room of an educational medical facility, the compliance rate reached 74 [ ]. According to 46 research conducted by various specialists all over the globe, hand hygiene (HH) compliance enhanced after the course of action, ranging from 1% to 66%, with the mean net change being a 26% rise [ ]. Hand hygiene and the use of sterile surgical gloves improved by 30.002% and 42.5%, respectively, in the study we conducted. In pre-evaluation, the study by Biddhya and Bista had a mean compliance of 88.88%, but our investigation had a mean of 37.14% and 43.75%, respectively [ ]. After observing this, we educated the interns with a pictorial guide, video demonstration, and individual demonstration to explain the steps according to WHO guidelines. After that, we performed a post-evaluation, which revealed that the average compliance was 62.14% and 86.25%, respectively.",
"According to a study on hand washing and gowning compliance conducted in Indonesia, 83.12% of surgical residents adhered to the rules [ ]. In the same study, taking off the gloves' covering by hand from beneath the sleeves of the garment had the lowest mean score, while in our analysis, criteria 9 in Table and criteria 7 in Table had the lowest mean. New research on the in vivo efficacy of alcohol-based hand scrubbing, as well as the low risk of rashes related to their use, is highlighted [ ].",
"An observational study done by Anargh et al. assessed the knowledge about hand hygiene among 100 healthcare workers in tertiary healthcare facilities. The study was questionnaire-based and concluded that inadequate compliance was seen despite training, and alcohol-based rubs provided a false sense of security [ ]. A similar study conducted in Nigeria on 173 healthcare workers which included hospital auxiliary staff showed good compliance with hand hygiene practices [ ]. After observing all the studies and the present survey conducted by our study, we realized the need to re-audit frequently and sensitize pictorial guides, video demonstrations and individual demonstrations to impart knowledge and improve compliance among healthcare workers.",
"Limitations of the study",
"The small sample size is the major limitation of this study. Such studies should be done at many centres for validity. Lack of sufficient review of the literature and original studies on aseptic procedures are other limitations.",
"This clinical audit was conducted for the first time in dental college, proving that additional audits must be conducted to improve patient safety. This study investigated how young dental surgeons knew before and after being evaluated for using the WHO-recommended standard sterile surgical glove technique. This study identified significant changes in the variables both before and after the intervention. Despite many interns' greatest attempts to follow the WHO recommendations for hand hygiene and surgical gloving methods, many still need to live up to expectations. On the contrary, as this study shows, the training sessions resulted in quite a lot of progress. Therefore, we must regularly undertake clinical audits and resensitize operating personnel to make optimistic changes to clinical practice. Based on the previous data, more regular audits should be performed to increase adherence to accepted protocols. This can result in a major improvement in eliminating health risks, which can still aid a nation's economy by lowering the number of prolonged hospital stays and the burden of iatrogenic diseases."
] |
PMC10757273
|
Clinics
|
Preliminary outcomes of five-year survival for ovarian malignancies in profiled Serbian Oncology Centre
|
04-05-2023
|
Highlights • Analyzing predictors of survival in patients with ovarian carcinoma is crucial. • Independent estimators of mortality in ovarian carcinoma, are more precise by identifying histopathologic tumor grade, FIGO, and NACT. • The aforementioned predictors also involve the number of therapeutic cycles, type of surgery, and chemotherapy response. • Poor chemotherapy response increases the hazard ratio for mortality. • Significant predictors of survival in ovarian carcinoma are the absence of recurrent disease and lymphovascular space invasion.
|
[
"With the aging of the world's population, the authors are faced with changes in morbidity and mortality causes and cancer is becoming the leading cause of death. It is estimated that in the continent of Europe, which counts close to 10% of the world's population, there are about 23.4% newly diagnosed cancers and about 20.3% cancer-related deaths. In the world population, lung cancer is the most common cancer type and the most common cause of death in cancer cases. Breast cancer is the most frequently diagnosed and the most common cause of cancer-related death among women .",
"Although ovarian cancer, per se , is not very common and accounts for only 3% of the general population of women, it is the fifth most common cause of death among women diagnosed with malignancy . Age-adjusted incidence is calculated as 12.5 per 100.000 women . The incidence and mortality rates are higher in older women and increase with age, hence the probability of getting this malignancy is higher in the n who are 50 years. However, the disease can be diagnosed at any age . Genetics is a significant risk factor for ovarian cancer, and there is also hereditary breast and ovarian cancer syndrome, which occurs in one in 500 women. That is the result of an autosomal dominant mutation of the BRCA1 or BRCA2 gene. Mutation of this specific gene . The majority of ovarian cancer patients are diagnosed in the advanced stage of the disease, which is associated with poor prognosis compared to localized disease where the 5-year survival is about 92% . In the case of the advanced tumor stage, the 5-year survival rate is low and is only about 29.2% . In addition, 70%‒90% of women with ovarian cancer in the late stage experience the recurrence of the disease within 18 months of diagnosis .",
"Several studies have focused on the immunology, pathogenesis, and therapy of ovarian cancer, suggesting the role of T-cell infiltration and Tumor-Associated Macrophage with its role in cell apoptosis and PD1/ PD-L1, and Progression-Free Survival . These long-term survivors also include a proportion of women with poor clinical characteristics at diagnosis, such as advanced-stage disease or performing suboptimal debulking surgery. The predictors of long-term survival are not well understood, and it remains unknown whether associations between patient characteristics and risk of mortality differ across the survival trajectory and whether these associations vary according to histologic type . The present study purposed to determine the characteristics of ovarian carcinoma and to analyze predictors of survival in patients with ovarian carcinoma.",
"This study was conducted according to the declaration of Helsinki and approved by the Ethical Board of Oncology Institute of Vojvodina under the 4/20/2-3707/2-6 approval number. It has been designed as a retrospective cohort study and included patients with diagnosed ovarian carcinoma treated at the Clinic of Operative Oncology, Oncology Institute of Vojvodina in the period from 2012 to 2016. Clinical and radiological assessment was performed during the five-year follow-up period. Of 75 patients with ovarian carcinoma 72 were included in the analysis. Three of 75 cases were excluded due to missing follow-up. The data about the histological type of tumor, disease stage in terms of median age. However, the FIGO stage had a significant impact on survival so women who were in FIGO I and II stage had a higher chance to survive compared with those in stages III and IV.",
"The preliminary results of the present study exhibited an expected 5-year survival of 40%. The patients with LVSI had significantly lower survival and poor prognosis compared with those without LVSI. This is comparable with data from the literature. Li and colleagues [26]. conducted a meta-analysis that also revealed an increased risk of non-survival in patients with LVSI. The authors calculated pooled HR for all 13 articles included in the analysis and demonstrated a significantly augmented risk of disease progression in patients with LVSI presence of participants. The advanced stage was significantly associated with an increased risk of LVSI presence, and the univariate analysis also revealed the expression of SNAI1 and SNAI2 were all positively correlated with LVSI presence. The advanced stage are diagnosed with FIGO stage III‒IV. In this setting, primary cytoreductive surgery followed by taxane- and platinum-based combination chemotherapy is a well-established management strategy. The goal of surgery should be the complete removal of all macroscopic diseases, as “complete cytoreduction” is one of the most important prognostic factors of survival. This is in accordance with the present analysis which also demonstrated a significant impact of surgery type on survival. In the analysis, there were more than 50% in the survivals group with at least optimal debulking surgery. Also, patients with stage IV disease who underwent Neoadjuvant Chemotherapy, while the median BMI was 25.0 kg/m^(2) (IQR 22.0‒29.7 kg/m^(2)), with 51 (21.4%) of patients were obese (BMI ≥ 30.0 kg/m^(2)). The majority of cases had tumors with serous histopathology (91.6%) and FIGO Stage III cancer (82.3%) and BRCA mutations were present in 22 cases (9.2%). The median CA-125 at diagnosis was 457 U/mL (IQR 134‒1367 U/mL). Debulking surgery was conducted in 94.1% of the cases. One hundred twenty-one (50.8%) patients did not have residual disease after surgery, while 60 (25.2%) and 34 (14.3%) had a < 1 cm or ≥ 1 cm residual disease, respectively. Approximately half (53.4%) of the patients received NACT. Most patients (93.3%) received carboplatin with paclitaxel as the first chemotherapy. As expected, the majority of patients (92.3%) responded to first-line chemotherapy (PR/CR). However, response rates dropped markedly with each additional line of treatment. By line 5, over 60% of patients had PD, while only 4.3% and 12.8% had a recurrence or progressive disease, respectively. The present analysis exhibited that disease recurrence significantly impacted survival in patients with ovarian carcinoma. In addition, response to chemotherapy was a significant predictor of survival in the present study. This is to the results of the above-mentioned work of Kessous et al. where the response to chemotherapy predicted OS regardless of the line of chemotherapy and the difference was most pronounced in the first line, where patients with recurrent carcinoma did not have significantly improved overall survival compared with those with progressive disease. Even some of the baseline characteristics were similar to the analysis, which further supports the authors’ work and results, even though the sample was smaller.",
"In conclusion, as expected, the percentage of high-grade, advanced-stage ovarian cancer patients, per se , possessing a complete response to chemotherapy, absence of recurrent disease, and lymphovascular space invasion were significant predictors of survival in patients with ovarian carcinoma. Herein, the present results are following the outcomes of the other authors. Given the fact that some authors have shown that some patients with complete response to chemotherapy did not have significantly higher survival even if the number of therapy cycles was higher than six. Of note, that indicates that efforts should be made to identify tumor characteristics that could determine patients who will benefit from the standard treatment and those who need other, tailored treatment, preventing overtreatment. Herewith, emerging data regarding precision medicine and molecular-based personalized treatment modalities are promising and will likely modify the way the authors provide multiple lines of treatments in the near future. Bene diagnoscitur bene curatur.",
"The clinical data used to support the findings of this study are available from the corresponding author upon request.",
"None declared.",
"Bojana Gutic: Conceptualization, Data curation, Formal analysis, Investigation, Methodology, Project administration, Resources, Validation, Visualization, Writing – original draft. Tatjana Bozanovic: Investigation, Methodology, Project administration, Resources, Validation, Visualization. Aljosa Mandic: Investigation, Methodology, Project administration, Resources, Validation, Visualization. Stefan Dugalic: Investigation, Methodology, Project administration, Resources, Validation, Visualization. Jovana Todorovic: Investigation, Methodology, Project administration, Resources, Validation, Visualization. Miroslava Gojnic Dugalic: Investigation, Methodology, Project administration, Resources, Validation, Visualization. Demet Sengul: Investigation, Methodology, Resources, Software, Supervision, Validation, Visualization, Writing – original draft, Writing – review & editing. Dzenana A. Detanac: Investigation, Methodology, Validation, Visualization, Writing – review & editing. Ilker Sengul: Investigation, Methodology, Project administration, Resources, Software, Supervision, Validation, Visualization, Writing – original draft, Writing – review & editing. Dzemail Detanac: Investigation, Methodology, Validation, Visualization, Writing – review & editing. Tugrul Kesicioglu: Investigation, Methodology, Validation, Visualization. José Maria Soares Junior: Investigation, Methodology, Project administration, Software, Validation, Visualization, Writing – review & editing.",
"The authors declare no conflicts of interest."
] |
PMC10603682
|
Animals : an Open Access Journal from MDPI
|
Hepatitis E Virus in Livestock—Update on Its Epidemiology and Risk of Infection to Humans
|
17-10-2023
|
Simple Summary Hepatitis E virus (HEV) is a public health problem worldwide, as it is an important food pathogen that humans can obtain from animals. The most common way to infect humans is by consuming contaminated, undercooked meat or raw meat from infected pigs. However, domestic cattle, small ruminants such as sheep and goats, and farm rabbits should not be underestimated as possible sources of HEV infection for humans. Many studies have detected HEV in milk from infected ruminants. Thus, the consumption of raw milk might lead to infection. Among livestock, chickens are susceptible to avian HEV, which can cause symptomatic disease but is not dangerous to humans. Avoiding eating undercooked meat from certain livestock species and following basic hygiene rules when in contact with animals that may be a source of HEV are effective preventive measures for hepatitis E in humans. Abstract Hepatitis E virus (HEV) is a public health problem worldwide and an important food pathogen known for its zoonotic potential. Increasing numbers of infection cases with human HEV are caused by the zoonotic transmission of genotypes 3 and 4, mainly by consuming contaminated, undercooked or raw porcine meat. Pigs are the main reservoir of HEV. However, it should be noted that other animal species, such as cattle, sheep, goats, and rabbits, may also be a source of infection for humans. Due to the detection of HEV RNA in the milk and tissues of cattle, the consumption of infected uncooked milk and meat or offal from these species also poses a potential risk of zoonotic HEV infections. Poultry infected by avian HEV may also develop symptomatic disease, although avian HEV is not considered a zoonotic pathogen. HEV infection has a worldwide distribution with different prevalence rates depending on the affected animal species, sampling region, or breeding system.
|
[
"Hepatitis E is an important public health problem worldwide. The World Health Organization estimates that 20 million infections with Paslahepevirus balayani have higher HEV-related seroprevalence rates than the general population [ ]. All livestock professionals should be aware of the risk of zoonotic-acquired hepatitis E. Recent changes in HEV epidemiology might be related to the zoonotic nature of the disease.",
"In this paper, a bibliographic review of the literature on HEV is performed to gather the latest data regarding the prevalence among livestock species worldwide and the threat to humans due to HEV in livestock.",
"The HEV genome contains a positive-sense monopartite RNA of 6.4–7.2 kb with three open reading frames and Paslahepevirus alci, which was detected in moose [ , ]. Eight different genotypes have been assigned to the species P. balayani : HEV-1 to HEV-8 [ ]. HEV-1 to HEV-4 genotypes are commonly associated with HEV infection in humans. Of these genotypes, HEV-1 and HEV-2 are restricted to humans, whereas HEV-3 and HEV-4 are considered zoonotic. HEV-3 and HEV-4 are further classified based on phylogenetic grouping. Currently, a total of three main clades of HEV-3 can be distinguished: clade 3.1, which includes subtypes a, b, c, h, i, and j; clade 3.2, which includes subtypes e, f, and g; and clade 3.3, which contains rabbit strains corresponding to the HEV-3ra subtype [ , , ]. Nine subtypes were determined among HEV-4: 4a–4i [ ]. Subtypes 4a, 4b, 4d, and 4 h are isolated in over 80% of cases [ ].",
"Domestic pigs, while HEV-4 is less prevalent in the pig world population. Nevertheless, in some countries, especially in the Western Pacific region, like China, India, or Indonesia, HEV-4 is as prevalent as HEV-3 or represents a predominant genotype. Susceptible pigs acquire HEV mainly from other shedding pigs. However, swine are also susceptible to HEV-3 and HEV-4 isolated from humans [ ]. Moreover, experimental studies show that infection with HEV-3 from rabbits is also possible in these animals [ , ]. Nevertheless, no evidence of natural cross-species transmission has been provided [ ]. Unusually, a human HEV-1 strain was reported in a domestic pig in 2018 in Uruguay, although pigs are not considered a natural reservoir for this genotype. Molecular methods quantified the viral load in the stool, and sequence analyses were performed. The investigated animal was simultaneously infected with HEV-3 and appeared not to have clinical symptoms. The authors suggest that pigs may occasionally, and perhaps accidentally, act as reservoirs for HEV-1 through an inter-species transmission mechanism. Detection of both genotypes in one animal means multiple sources of infection. Pigs are omnivorous; hence, a plausible alternative source of contamination could be through the consumption of contaminated food [ ]. The remaining genotypes; it was much higher in comparison with the remaining countries in which molecular studies were performed, whose prevalence was between 0.93%. The horizontal transmission of HEV-3 from wild boar to domestic pigs has been proven experimentally [ ]. On the other hand, swine manure might be a source of HEV infection of wild boar and other wildlife, since it is often used as a soil fertilizer. In terms of public health, the density of the pig population in a given region does not appear to be associated with a higher risk of HEV seropositivity in humans living in Germany and Denmark [ , ].",
"Pigs, like humans, are frequently infected with HEV via the faecal-oral route. Nucleic acids of the virus were also detected by nested RT-PCR from inside and outside farm buildings, on trucks, and in utility vehicles. Hence, the indirect transmission of the pathogen, especially during the movement of trucks and utility vehicles, plays an important role in HEV dissemination at a slaughterhouse site and throughout an entire network [ ]. The infection is usually asymptomatic, and mild to moderate liver and lymph node changes can be found in infected animals [ ]. Typically, the viral load peaks at 4–6 months of age, when passive immunity wanes. Infected pigs start shedding the virus about a week after exposure, for an average of 3 weeks. Viremia persists for 1–2 weeks. Shedding the virus with faeces and other excretions, e.g., urine, is of great epidemiological importance. The primary factor that plays a pivotal role in spreading and maintaining infection within the population in different farms is the accumulation of the virus in the environment [ ]. HEV can probably persist in the farm environment for an extended period. HEV-3 shows high stability on different surfaces virus or Porcine circovirus-2 may result in the prolonged excretion of HEV in co-infected pigs [ ]. Cao et al. [ ] arbitrarily set 8 weeks after infection as the time point separating acute and chronic infections. Their results showed that immunocompromised pigs with chronic infection shed the virus for at least an additional 5 weeks beyond 8 weeks post-inoculation [ ]. Moreover, HEV shedding is significantly increased and dramatically extended in pigs co-infected with PRRSV in young sows and 53.4%. Evidence of HEV infection and/or contact with this pathogen was found in cattle [ ] to 47% [ ]. HEV RNA was also found in other studies conducted in China, with the prevalence ranging from 0% in serum [ ], from 8.8% [ ] in faeces, and from 0% [ ] in cattle milk. The seroprevalence in India reached 4% in Lao People’s Democratic Republic [ ], and 14.5% [ ]. In Korea, HEV RNA was found in 1% [ ]. Neither anti-HEV antibodies in bovine sera nor HEV RNA in bovine faeces were found in Spain [ ]. The bovine faeces samples in Hungary [ ], and milk samples in Germany [ ] were also free from HEV RNA. On the other hand, 29.2% [ ].",
"In Africa, the seroprevalence reached 21.6% [ ] to 26.4% [ ].",
"Variations in the prevalence of HEV in cattle observed by different researchers may result from different breeding practices, of which the most critical factor influencing the increase in the prevalence of HEV is mixed breeding, including for many species. For domestic cattle, sheep, and goats, the incidence of HEV infections appears to be higher in rural areas where traditional mixed farming systems consist of small family farms with pigs and other domestic animals [ , , , ]. Cross-species transmission between ruminants and pigs is suggested by the detection of HEV-3 and HEV-4 that are genetically closely related to the HEV identified in domestic and wild ruminants and pigs or wild boars in the same geographical areas [ , , ]. Moreover, the frequent mixed breeding of cattle and pigs in rural China and the simultaneous lower seroprevalence rates in cattle compared with pigs in the same region are also probably related to cross-species transmission of the virus [ ]. However, keeping cattle and pigs in close contact did not always contribute to infection; HEV RNA was not detected in the faeces and milk of cows reared on mixed farms, rearing pigs and cattle, in China [ ] and Belgium [ ]. In a longitudinal study, the lower seroprevalence in cattle than in pigs may be related to the lower permissivity and/or transient seropositivity observed in calves and adult cows [ ]. The lack of association between the age of the cattle and seropositivity, observed in the study of Tialla et al. [ ], can be explained by temporary seropositivity. According to Tialla et al. [ ], the type and intensity of interspecies contacts and the hygiene prevailing on the farm may also influence the prevalence of anti-HEV antibodies in cattle [ ]. Farm rabbits are also considered a reservoir of HEV; however, keeping rabbits and cattle in close contact on the same farm has not been identified as a risk factor for an increased HEV seroprevalence [ ]. HEV RNA was also found in sheep kept close to investigated yellow cattle. Genome sequences of HEV strains isolated from the yellow cattle exhibited 95.1–99.8% homology with sheep-derived strains. This suggests the existence of complex mechanisms for the interspecies transmission of HEV and its circulation between populations of different animal and human species [ ].",
"Sheep confirmed this finding [ , , ].",
"The occurrence of HEV in small ruminants has been previously reviewed by Di Profio et al. [ ]. According to the authors, seropositive sheep were found in numerous countries on different continents, such as Asia serum samples [ ]. Subsequent studies confirmed that HEV was circulating in the Chinese sheep population, as HEV RNA was present in the serum. Available data indicate that HEV is highly prevalent in the population of Italian small ruminants [ ]. Two different reports demonstrated the presence of HEV RNA in the serum and faecal samples collected from sheep [ , ]. The first study obtained serum and faecal specimens from 192 sheep [ ]. HEV RNA was detected in 10.4%. HEV RNA was found in specimens from two seropositive farms, and the overall prevalence reached 3% of sheep livers and 2% to HEV infection comes from 1998, when anti-HEV antibodies were detected in caprine samples [ ]. In 2007, in India [ ], 100%, such as China, the USA, Egypt, Nigeria, Italy, Spain, and Bulgaria, confirmed the presence of antibodies against HEV in the sera of goats, with seroprevalence ranging from 0.6% to 46.7% [ , ].",
"The first HEV RNA detection in caprine specimens has been reported by Di Martino [ ]. Noteworthily, previous studies conducted in China in which samples collected from seropositive goats were also tested for the presence of HEV RNA failed to detect HEV genetic material; nevertheless, in one of them, by using a monoclonal antibody-based enzyme immunoassay, HEV antigens were found in caprine sera [ , , ]. In the Italian study, 9.2% being to the wild boar strain identified in the same geographical area [ ]. The high HEV prevalence in goats was also observed in the Yunan Province of China, where raw mutton and goat milk are traditionally consumed [ ]. Results of this study showed that 74.04% of caprine liver samples collected at slaughterhouses in the Tai’an region, China [ ]. Obtained isolates were classified into HEV-4, subgenotype 4f, and were closely related and 0.71% are considered another major HEV reservoir [ ]. These animals are a natural host of the rabbit HEV strain of the samples were positive for HEV RNA. Moreover, anti-HEV antibodies were found in 57%. In Korea, HEV RNA was detected in specimens collected from farm rabbits. Positive faecal samples came from two out of six examined rabbit farms; the prevalence was 6.4% of bile samples from farm rabbits and 23% [ ]. Interestingly, none of the samples collected from farm rabbits were positive in this study. However, this could result from the low number of samples tested were HEV-RNA-positive. Nevertheless, the above data indicate that HEV circulates in the Italian rabbit population [ ]. The presence of HEV RNA was also confirmed in the samples collected from farm rabbits in Russia [ ]. Three out of six surveyed farms were HEV-positive, and the virus was detected in 9 out of 206 faecal samples [ ]. In contrast, despite testing 372 liver samples, no HEV circulation in wild rabbits has been found in Spain [ ]. HEV genetic material and anti-HEV antibodies were confirmed in faecal and serum samples collected from two rabbit farms in Virginia, USA [ ]. A total of 16.5% [ , ].",
"Members of the genus Avihepevirus are phylogenetically distinct from other viruses in the Orthohepevirinae subfamily and have a different host range. It has been found only in birds. Avihepevirus magniiecur were successfully infected with avian HEV, as evidenced by their seroconversion to anti-HEV antibodies, viremia, and faecal virus shedding [ ]. Various animal species kept close to infected poultry may seroconvert, indicating exposure to the virus and the development of a humoral response. In a study conducted in China, 8/16 rabbits, 9/30 ducks, and 6/24 geese in the investigation were positive for anti-avian HEV antibodies. Part of the faecal swabs in rabbits, ducks, and geese were positive in a PCR targeting the detection of avian HEV ORF1 or ORF2 sequences [ ]. Avian HEV has only 50% similarity to HEV sequences isolated from humans or pigs; nevertheless, HEVs found in birds and pigs are ubiquitous viruses. There is likely frequent contact between each other, creating the potential for mutations that may contribute to crossing the species barrier and enabling the replication of avian HEV in pigs.",
"The range of animals proven to be susceptible to HEV infection has grown over the past two decades. The susceptibility of animals to infection is determined based on the detection of viral RNA in the samples taken from these animals and the possibility of developing a humoral response against the pathogen in response to infection detected with serological tests [ ]. Hepatitis E in humans and its etiological agent were described in detail in 1983 [ ]. To date, it has been detected in the human population in almost every country [ ]. Later studies showed over 90% similarity between human HEV strains and those obtained from pigs [ , ]. Humans are vulnerable to infection from HEV-1 to HEV-4, representing the main reservoir of HEV-1 and HEV-2. Zoonotic transmission is widely documented for HEV-3 and HEV-4, and one case of human infection with HEV-7 with a zoonotic origin has been described [ ].",
"HEV zoonotic infection may be foodborne or due to direct contact with infected animals [ , ]. Pigs are considered the main and apparent reservoirs of HEV-3 and HEV-4. These genotypes have been found in all stages of the human food chain, and the main route of transmission from pigs to humans is via undercooked or uncooked porcine meat products and offal [ ]. It was reported that approximately 2% and 11% of pig livers sold in Japan and America, respectively, are positive for HEV RNA [ , ]. Besides foodborne transmission, direct contact with porcine body excretions may be another route for zoonotic HEV, since it has been detected in nasal and rectal swabs [ ] and urine specimens [ ] from experimentally infected pigs. However, animal species other than pigs may significantly contribute to the spread of zoonotic HEV genotypes to humans. Cattle and small ruminants are the source of food for humans. The possibility of cattle-to-human HEV transmission by drinking contaminated unpasteurised milk [ ] or eating contaminated undercooked meat [ ] and offal purchased from local grocery markets between February 2017 and July 2018 in Seoul, Korea. The nucleotide sequence indicated that the found HEV genotype was closely related. One of the samples was identified as HEV-3 [ ]. Huang et al. [ ] investigated fresh pasteurised milk available at the market supplied by local farmers in China. A gavage of raw or pasteurised milk contaminated with HEV led to active infection in rhesus macaques and the detection of HEV RNA in their faeces and blood. Interestingly, pasteurisation could not inactivate HEV, and the gavage of pasteurised milk resulted in an active HEV infection in monkeys. However, Huang et al. [ ] proved that short-time boiling at 100 °C for 3 min could inactivate the HEV completely. Viral RNA was not detectable in either faeces or serum of the rhesus macaques inoculated with cooked samples containing HEV material [ ]. Homology analysis based on the complete sequence of the bovine HEV discovered in this study indicated that it shared 99.2~99.4% similarity to human HEV. Phylogenetic analysis revealed that all the HEV isolates from cow/milk belong to genotype 4 and subtype 4 h [ ]. Similarly to cattle and goats, sheep can spread HEV through mammary gland secretions. Two separate studies from Türkiye and the Czech Republic indicated the presence of HEV genetic material in sheep’s milk; 12.3% and 1.4% of analysed specimens were positive, respectively [ , ]. The above findings are of great importance and indicate that milk from farm ruminants, especially when raw, represents a potential source of infection for consumers [ ]. Data from China demonstrated a significantly higher level of anti-HEV antibodies among rabbit slaughterhouse workers than in the general population, implying a risk of cross-species transmission of HEV from rabbits to humans by direct contact [ ]. The HEV-3ra strain [ ] was detected in immunocompromised and immunosuppressed human patients [ , ]. Moreover, it was reported that healthy blood donors tested positive for HEV, and an isolated virus was related to HEV3-ra [ ]. Interestingly, the positive individuals had had no contact with rabbits, and only two ate rabbit products that were always well-cooked; this phenomenon can suggest waterborne transmission of HEV3-ra to humans [ , , ]. As mentioned, human infection with the HEV-7 genotype has also been described [ ]. To date, the only confirmed case of human infection with zoonotic HEV-7 was documented in a patient who regularly consumed camel milk and meat [ ].",
"There is a strong interdependence between the health of humans and animals and the environment, which is known as the One Health concept [ ]. This collaborative, multidisciplinary approach aims to promote, improve, and protect the health of all species [ ]. Since infections, mainly with HEV-3 and HEV-4, can be transmitted zoonotically, they should be included in the multidisciplinary One Health concept to improve the surveillance and control of this emerging infection and to prevent the spread from animal hosts to people. Available data indicate that HEV is circulating globally in human and livestock populations, and infections with this agent in livestock animals are much more common than previously thought. Human hepatitis E associated with HEV-3 and HEV-4 of animal origin result from close contact with infected livestock or from ingesting contaminated meat products or milk and is often underdiagnosed. Therefore, the consumption of under-cooked raw meat products should be avoided, especially by individuals at high risk of developing severe hepatitis E. Pigs are the main animal reservoir of zoonotic HEVs. Infection in this species has been noted in numerous countries on almost every continent. Nevertheless, viral RNA of HEV-3 and HEV-4 and/or anti-HEV antibodies have also been detected in samples collected from other species of farm animals, including cattle, sheep, goats, and rabbits. Due to the possibility of cross-infection, domestic pigs, ruminants, rabbits, and even poultry should be kept without close contact. Avian HEV poses no threat to humans, although its circulation between livestock populations may lead to changes in the genome and lead to potential infectivity to mammals. It is crucial to highlight that good hygiene practices (e.g., changing clothes or showers after dealing with farm animals) among farmworkers and other people who have close contact with livestock are advisable to minimise the risk of zoonotic HEV infection and of spreading the pathogen among susceptible animals. Knowledge concerning the epidemiology of this virus is essential in view of public health concerns."
] |
PMC10752250
|
Ecology and Evolution
|
Between‐year and spatial variation in body condition across the breeding cycle in a pelagic seabird, the Red‐billed Tropicbird
|
27-12-2023
|
Abstract Body condition in pelagic seabirds impacts key fitness‐related traits such as reproductive performance and breeding frequency. Regulation of body condition can be especially important for species with long incubation periods and long individual incubation shifts between foraging trips. Here, we show that body condition of adult Red‐billed Tropicbirds ( Phaethon aethereus ) at St Helena Island, South Atlantic Ocean, exhibited considerable variation between years (2013–2017) and between different stages of the breeding cycle. Females took the first incubation shift following egg laying, after which males and females alternated incubation shifts of varying length, ranging from <1 to 12 days. Body condition declined in both sexes during an incubation shift by an average of 22 g (2.83% of starting mass) per day and over the incubation period; mass loss was significantly greater during longer incubation shifts, later within a shift and later in the total incubation period. There was also significant differences in incubation behaviour and body condition between years; in 2015, coinciding with a moderate coastal warming event along the Angolan‐Namibian coastlines, adults on average undertook longer incubation shifts than in other years and had lower body condition. This suggests that substantial between‐year prey fluctuations in the Angola Benguela upwelling system may influence prey availability, in turn affecting incubation behaviour and regulation of body condition. Adults rearing chicks showed a significant reduction in body condition when chicks showed the fastest rate of growth. Chick growth rates during 2017 from two localities in the Atlantic Ocean: an oceanic (St Helena) versus neritic (Cabo Verde) population were similar, but chicks from St Helena were overall heavier and larger at fledging. Results from this multi‐year study highlight that flexibility and adaptability in body condition regulation will be important for populations of threatened species to optimise resources as global climate change increasingly influences prey availability.
|
[
"Body condition in birds is a key factor underlying the success of breeding, migration and moult. In seabirds, parental body condition is known to influence and impact breeding and foraging regimes. In pelagic seabirds, spending much of their time at sea and only returning to land to breed, it is challenging to understand the pressures acting upon them, such as the energetic costs of breeding and how they respond to these costs. While body condition and its regulation in Procellariiformes Phaethontiformes.",
"In seabirds, the division of breeding duties can influence breeding success. Males and females generally share breeding duties equally, but differing parental investment between the sexes while breeding can occur in some species. Differences between sexes in breeding behaviour and regulation of body condition have been attributed to sexual size dimorphism. Tropicbirds are typically monomorphic, with limited or no sexual size dimorphism; however, sex differences in behaviour are also not uncommon in monomorphic seabirds.",
"Food resources are often scarce and patchily distributed in tropical marine environments. While provisioning for their chick, pelagic seabirds must therefore find an equilibrium between reaching productive areas, searching for prey, returning to the chick at regular intervals to feed and/or guard while the partner forages and self‐provisioning. Parental provisioning frequency and meal size can influence chick growth rate, along with attendance at the nest providing temperature regulation and protection from predators and rival territorial conspecifics.",
"Bimodal foraging strategies are known to influence body condition. This requires parent birds enduring extended fasting periods during incubation shifts, and balancing energy expenditure in provisioning for a chick with provisioning for themselves. Seabirds with long incubation periods typically lay a single egg clutch and fast while incubating while their partner is foraging at sea. The length of an incubation shift can substantially negatively affect adult body condition, although the rate of loss of condition is influenced by individual differences in metabolic rates. Chick provisioning periods in pelagic seabirds are also typically extended. These life history traits render species such as tropicbirds particularly vulnerable to unpredictable variations in food resources. There is a lack of knowledge of tropicbird chick growth rates, which have either been poorly documented and/or date from estimates obtained decades ago, when foraging conditions may have been very different.",
"Chick growth and adult body condition can also vary among breeding seasons and different localities, due to inter‐annual variation in oceanographic conditions caused by El Niño Southern Oscillation. In the South Atlantic, south‐east trade winds create inter‐annual fluctuations of the Angola Benguela upwelling system, leading to warm ‘Benguela Niño’ and cold ‘Benguela Niña’ events. Yet, in comparison with climate and oceanographic oscillations in the Pacific Ocean, where the effects have been extensively studied, little is known whether or how these oscillations might impact tropical south Atlantic ecosystems. Many seabird populations are located adjacent to continental shelves, where coastal upwelling systems can influence productivity, and thus local food availability can also influence adult body condition, breeding performance and foraging behaviour. In contrast, isolated oceanic populations that are out of reach of the coast or nearby land masses may be reliant on deep‐sea topographical features, such as seamounts for enhanced prey availability.",
"This study aimed to test several hypotheses about the role of body condition in mediating the breeding behaviour of Red‐billed Tropicbirds. Firstly, we tested for between‐year differences in adult body condition, predicting that adults would exhibit poorer body condition in years of reduced food availability possibly mirroring variation in the environment among years. Secondly, we tested for changes in adult body condition between and within breeding stages, expecting that body condition would decline across the breeding season due to energetic constraints and that body condition would be negatively associated with the length of individual incubation shifts when the incubating bird is unable to forage. Thirdly, we tested the null hypothesis of equal parental incubation and provisioning effort between the two sexes, predicting that due to the limited sexual size dimorphism of Red‐billed Tropicbirds parental investment is likely to be similar between the sexes. Fourthly, we tested for differences in parental body condition at nests with differing reproductive outcomes: St Helena in the central south Atlantic, located on the eastern edge of the South Atlantic subtropical Gyre in the path of the south‐east trade winds and the South Equatorial Current. Cabo Verde, consists of 10 volcanic islands that lie between 600 and 850 km west of Senegal, Africa, located at the eastern boundary of the North Atlantic subtropical gyre at the southern limit of the Canary Current. The waters around St Helena are characterised by a generally low chlorophyll a concentration with substantial variation in spatial distribution between years, whereas Cabo Verde is considered a more productive oceanic region with more enriched waters).",
"We obtained 1061 measures of adult body mass from 122 individuals as a reliable index of body condition. A minimum of 24 cavities per year were monitored between 21st August and 21st December, over a 5‐year period. Whenever possible, Bushnell Trophy Cameras were positioned near the entrance of cavities so that the arrival and departure of adults were continuously monitored. Cameras captured two pictures consecutively after the camera was triggered with a minimum interval of 5 s between successive triggers. All adults in cavities were caught by hand and fitted with a standard metal ring. To enable individual identification of breeding pairs without frequent capture or handling, any breeding adults were marked with a unique combination of colour marks on their head feathers and July to January at St Helena. Tropicbirds have an extended incubation period with incubation shifts lasting up to 16 days and chick rearing period that can last 12–13 weeks before fledging. Red‐billed Tropicbird populations were estimated to be up to 246 pairs at St Helena but as few as 1100 pairs at Cabo Verde.",
"Where possible, for each adult during incubation, we estimated the following covariates along with its weight:) was defined as the number of days from laying an egg to hatching a chick, based on known laying and/or hatch dates.. When weighing adults rearing chicks, we estimated the age of the chick and the growth stage of plumage.",
"Incubation shifts at St Helena were calculated using a combination of, known to weigh at least 500 g and absent from its cavity during subsequent observations, and/or camera images showed the chick leaving the cavity entrance at a near‐fledged stage.",
"Standard biometric measurements for all chicks at St Helena in the 2017 breeding season. Chick biometric data at Cabo Verde were pooled from two islands and one islet during the equivalent breeding season in 2017. A subset of biometrics implemented in R‐studio. All generalised linear mixed models, all likelihood ratio tests and all generalised additive mixed models or mgcv package, following Thomas and Lello ( ). Significant effects in final models were plotted using the R packages ggplot2 , ggpubr , hrbrtheme . Estimated parameters for the growth curves were calculated in the R package FlexParamCurve .",
"We tested for any effect of the monitoring period. We concluded that the variable was a significant predictor of body condition if the model containing the variable of interest was significantly better than the null model in case incubation shift length was influenced by breeding outcome) and the proportion of incubation shift completed. For the chick rearing period, we also included the age of the chick.",
"Descriptive statistics were generated for incubation shift frequency using a subset of data from pairs containing individuals of known sex, that were monitored from laying to hatching and where the shift sequence could be identified. We used GAMMs to explore whether variation in the time spent incubating an egg could be explained by any differences between sexes, years, hatching outcome or incubation periods. Given that our data were comprised of multiple incubation shifts from the same individuals and nesting attempts, we included the random effects of individual identity and nest identity. A gamma distribution with a log link function was used to model the response variable. The full model included sex, hatching outcome and year as additive terms, as well as an interaction between sex and day of incubation period, hypothesising that incubation shift length may differ between successful and unsuccessful nests, years and sexes. The interactive effect of sex and day of incubation period was included, as tropicbirds are known to alternate incubation duties between sexes. Model selection was based on a stepwise deletion process, by removing the least significant term at each step, evaluated by an ANOVA test and resulting change in AIC value until the model with the lowest AIC value was identified.",
"The rate of mass loss is a reliable index of energy costs incurred by fasting birds during incubation. The rate of mass loss during incubation was examined using the proportion of mass loss per day, calculated from a subset of masses during incubation from individuals that had more than one mass measurement during the same incubation shift. The difference between the two mass measures was divided by the number of days between measures, divided by the initial mass ×100, to give the proportional mass loss per day, for each individual. To investigate if the rate of mass loss during an incubation shift varied between years, sexes and between incubation outcome to allow for a regional comparison with Ascension Island. Binomial tests were used to examine using the equation:where y is the response variable.",
"To compare growth rates between geographical regions, we calculated the proportion of growth per day for each chick, firstly by calculating the difference in mass between two consecutive measures, then dividing the difference by the number of days between measures and by the initial mass. This gave the proportion of mass lost per day. A Gaussian GAMM with ‘identity’ link function was then used to test for effects of region on the proportion of growth by chick age. Nest identity was treated as a random effect to account for repeated measures from individual chicks and region as a fixed factor."
] |
PMC10246788
|
PLOS ONE
|
Trace quantification of GL-V9 and its glucuronide metabolites (5-O-glucuronide GL-V9) in Beagle dog plasma by UPLC–MS/MS and its application to a pharmacokinetic study
|
07-06-2023
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GL-V9, a new synthetic flavonoid derived from wogonin, has shown beneficial biological functions. In this study, accurate and sensitive UPLC–MS/MS methods were developed and validated for the quantification of GL-V9 and its glucuronide metabolite (5-O-glucuronide GL-V9) in Beagle dog plasma. The chromatographic separation was performed on a C 8 column (ACE Excel 5 C 8 50×3.0 mm) using 0.1% formic acid and acetonitrile were used as mobile phase. Mass detection was performed on a triple quadrupole tandem mass spectrometer equipped with an electrospray ionization (ESI) interface operating in positive ion mode. Quantitative analysis was performed in multiple reaction monitoring (MRM) mode with the transitions of m/z 410.2→126.1 for GL-V9, m/z 586.3→410.0 for 5-O-glucuronide GL-V9 and m/z 180.0→110.3 for phenacetin (internal standard), respectively. The calibration curves for GL-V9 and 5-O-glucuronide GL-V9 showed excellent linearity over the concentration range of 0.5–500 ng/mL with correlation coefficient greater than 0.99. The intra- and inter-day accuracies were within 99.86% to 109.20% for GL-V9 and 92.55% to 106.20% for 5-O-glucuronide GL-V9, respectively. The mean recovery was 88.64% ± 2.70% for GL-V9, and 92.31% ± 6.28% for 5-O-glucuronide GL-V9, respectively. The validated method was successfully applied to the pharmacokinetic study in Beagle dogs after oral and intravenous administration. The oral bioavailability of GL-V9 was approximately 2.47%~4.35% in Beagle dogs and reached steady state on the fifth day after repeated dosing.
|
[
"Cancer, the abnormal growth of cells, is an enigmatic and frightening disease or group of diseases that places an enormous burden on society worldwide. Cancer occurs with the involvement of a variety of factors, genes, and pathways and shows multiple stages [ , ]. In recent years, advances such as exploring molecular signaling pathways and modulating the cellular microenvironment have improved treatments of various cancer. Much effort is still needed to be done to discover and develop innovative drugs involved in various anticancer mechanisms.",
"5-hydroxy-8-methoxy-7-(4-(pyrrolidin-1-yl) butoxy)-4 Hchromen-4-one,, is composed of a typical chemical structure of flavonoids, with two benzene rings and senescent breast cancer cells [ ], upregulate expression of Trx-1 through activation of the AMPK/FOXO3a pathway and ameliorate the effect of DSS-induced colitis on oxidative stress [ ], induces p53 associated senescence and catastrophic mitosis in malignant T cells at sublethal doses [ ] and inhibits the expression and nuclear translocation of Trx-1, followed by inhibition of the DNA binding activity of HIF-1α, by suppressing the Trx-1/Ref-1 axis [ ], i.e. GL-V9 exhibited extensive anti-tumour mechanisms, including anti-tumor immunity, redox metabolism, cell proliferation, autophagy, apoptosis, cell cycle, and so on. On the other hand, for flavonoids, due to the presence of extensive hydroxy groups, phase II metabolism cannot be neglected [ ]. The literature had shown that GL-V9 showed extensive metabolism and the 5-O-glucuronide GL-V9 is the only glucuronide metabolite and the dominant product of GL-V9 phase II metabolism in vivo and in vitro in the previous study [ , ]. Wogonin and its glucuronidation metabolite may possess similar anticancer activities. The basic pharmacokinetic characteristics of GL-V9 in rats were investigated after oral and pulmonary administration. Double peaks were observed due to the presence of enterohepatic after oral administration and the bioavailability was about 8.54% in rat [ ]. These proven pharmacodynamic and pharmacokinetic properties of GL-V9 are just the tip of the iceberg, and much more work further needs to be done on GL-V9. Meanwhile, we should explore the characteristics of the its glucuronide metabolite and 5-O-glucuronide GL-V9 acetate were synthesized by China Pharmaceutical University [ ]. Phenacetin in Beagle dog plasma using one assay method and we actually did it, however, in evaluation of the specify, we found that the interference of 5-O-glucuronide GL-V9 to GL-V9 did not meet the acceptance criteria and when analyzing 5-O-glucuronide GL-V9 alone, we detected GL-V9, linear within a certain of concentration range. GL-V9 and other compounds reacted under the protection of nitrogen to synthetic 5-O-glucuronide GL-V9 [ ], that is, the standard of 5-O-glucuronide GL-V9 may mix with GL-V9. And the fact is that the standard of 5-O-glucuronide GL-V9 contains GL-V9.",
"The LLOQ for both analytes was 0.5 ng/mL, at which the signal-to-noise ratio was >10 and the accuracy and precision met the requirements.",
"The precision and accuracy were assessed at different concentration levels and the results are shown in . The result suggested that the two methods were accurate and reproducible for the determination of GL-V9 and 5-O-glucuronide GL-V9, respectively, in dog plasma.",
"The precision of internal standard normalization MF of GL-V9 and IS-thaw.",
"Reproducibility, assessed by repeating measurements of the QC samples to assess precision and accuracy, met the acceptance criteria, indicating the samples could reinject in case of instrument interruptions or other reasons such as equipment failure."
] |
PMC10754979
|
Frontiers in Neuroscience
|
TSPNet: a time-spatial parallel network for classification of EEG-based multiclass upper limb motor imagery BCI
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15-12-2023
|
The classification of electroencephalogram (EEG) motor imagery signals has emerged as a prominent research focus within the realm of brain-computer interfaces. Nevertheless, the conventional, limited categories (typically just two or four) offered by brain-computer interfaces fail to provide an extensive array of control modes. To address this challenge, we propose the Time-Spatial Parallel Network (TSPNet) for recognizing six distinct categories of upper limb motor imagery. Within TSPNet, temporal and spatial features are extracted separately, with the time dimension feature extractor and spatial dimension feature extractor performing their respective functions. Following this, the Time-Spatial Parallel Feature Extractor is employed to decouple the connection between temporal and spatial features, thus diminishing feature redundancy. The Time-Spatial Parallel Feature Extractor deploys a gating mechanism to optimize weight distribution and parallelize time-spatial features. Additionally, we introduce a feature visualization algorithm based on signal occlusion frequency to facilitate a qualitative analysis of TSPNet. In a six-category scenario, TSPNet achieved an accuracy of 49.1% ± 0.043 on our dataset and 49.7% ± 0.029 on a public dataset. Experimental results conclusively establish that TSPNet outperforms other deep learning methods in classifying data from these two datasets. Moreover, visualization results vividly illustrate that our proposed framework can generate distinctive classifier patterns for multiple categories of upper limb motor imagery, discerned through signals of varying frequencies. These findings underscore that, in comparison to other deep learning methods, TSPNet excels in intention recognition, which bears immense significance for non-invasive brain-computer interfaces.
|
[
"Brain-computer interface. Among various techniques, electroencephalography. A multitude of algorithms have been developed for EEG pattern classification in diverse BCI applications. In their research, Wang et al. redefined the common spatial pattern proposed a deep learning framework that incorporates convolutional and recurrent neural networks. EEG-based BCI applications commonly rely on four main types of neurophysiological patterns, namely, steady-state visual evoked potential, event-related potential, movement-related cortical potentials, and motor imagery. Among these EEG applications, MI has garnered increasing attention within BCI systems due to its ability to elicit oscillatory neural activity in specific frequency bands over the motor cortex region without external stimuli.",
"In previous research on MI, Duan et al. proposed a binary standard task-related component analysis method. Additionally, they adapted the structure of the bSTRCA method for multi-class standard task-related component analysis was developed by integrating filter bank selection into mSTRCA. This method is applied to classify multi-class limb movements by segmenting MRCP signals into low-frequency filter banks. It optimizes multi-channel signals within these banks using spatial filters to extract correlation features, which are then combined and classified using a support vector machine. Jin et al. introduced a sparse Bayesian ELM-based algorithm to enhance the classification performance of MI. Jin et al. proposed a correlation-based channel selection introduced a novel algorithm called temporally constrained sparse group spatial pattern presented a novel sparse group representation model introduced a new classification framework that incorporates the concept of Riemannian geometry into the manifold of covariance matrices. Aghaei et al. proposed separable common spatial-spectral patterns. Beyond its application in computer vision, DL has also found utility in various domains, including brain-computer interfaces have demonstrated that advancements in machine learning, such as batch normalization and exponential linear units, when combined with a carefully curated training strategy, have significantly enhanced the performance of deep convolutional neural networks introduced a two-modality, four-category BCI classifier based on motor imagery involving movements of the left and right wrists. Meanwhile, Hajinoroozi et al. put forward an innovative channel-wise convolutional neural network conducted a study on the classification of EEG motor imagery signals using convolutional neural networks, the Spatial Dimension Feature Extractor. Traditional signal processing methods are based on the theoretical analysis of linear systems, which inevitably results in the loss of a significant amount of information carried by the original signal. In order to extract complex features in the time dimension, we propose a Time Dimension Feature Extractor(·) can be defined as",
"where, x _(LT) represents the shallow time feature vector, x _(in) is the input vector for the shallow time feature extraction step, σ denotes the ReLU activation function, Γ represents the residual mapping to be learned, and w 1 × 1 64 and w 1 × 3 64 are the weights of 1 × 1 and 1 × 3 convolutional kernels with 64 channels, respectively. The shallow time feature extraction step uses residual convolutional blocks with kernel sizes of 1×1 and 1×3 in parallel to fuse different-level features of the input x _(in) into the shallow time feature vector. Similarly, the middle time feature extraction step H _(MT)(·) and the deep time feature extraction step H _(HT)(·) can be defined as",
"where x _(MT) represents the middle time feature vector, x _(HT) represents the deep time feature vector, and it is also the time dimension output feature vector of the TDFE module.",
"Regarding spatial dimension feature extraction, we introduce two spatial feature extractors. The Spatial Dimension Feature Extractor represents the spatial dimension output feature vector, β is the number of residual paths, σ denotes the ReLU activation function, Γ signifies the residual mapping to be learned, and w 1 × 1 512 , w 3 × 1 512 , and w 5 × 1 512 are the weights of 1 × 1, 3 × 1, and 5 × 1 convolutional kernels, each with 512 channels.",
"To extract parallel features from both the time and spatial dimensions, we propose a Time-Spatial Parallel Feature Extractor through X ∈ R ^(H × W)and transpose matrix X ^(⊤):",
"where, M ∈ ℝ^(H × H) represents a weight matrix. The elements of Q reflect the similarity between the time dimension and spatial dimension features. As M is a square matrix, its diagonalization can be expressed as:",
"where P is an invertible matrix, and D is a diagonal matrix. Subsequently, Eq., …, X ^(M)}. The real labels of the test dataset are denoted as Y = { y ^(1), …, y ^(M)}, where M represents the total number of test trials. f ( X , ω) is a well-trained TSPNet classifier, where ω represents the classifier's parameters. First, the test dataset T is input into the classifier to obtain the predicted labels Y _(p).",
"We then compare the predicted labels Y _(p) with the real labels Y to identify the correctly recognized test dataset, denoted as T _(c). Next, T _(c) is filtered using filters with frequency ranges, EEGSym, DeepConvNet, EEGNet-8,2] using two datasets. Finally, we perform experiments related to feature visualization.",
"Dataset I was collected through our experiments. We recruited 10 healthy participants aged between 24 and 38 years, with a mean age of 30 years and is available in the BNCI Horizon 2020 database at “http://bnci-horizon-2020.eu/database/data-sets.” It includes electroencephalography for model training, and the optimizer parameters are detailed in . The development of TSPNet is carried out using MATLAB R2020b, EEGSym, DeepConvNet, and EEGNet-8,2. These methods are based on convolutional neural networks for EEG signal classification. To adapt these models to our datasets, we modify the classification number of the output layer to six, as required by the two datasets used in this study. Originally designed for EEG signals of 128 and 250 Hz, we down-sample the EEG signals in Dataset I and Dataset II to match their respective architectures. Training these models follows the same procedure as that of the TSPNet model.",
"In this section, we evaluate the impact of the proposed TDFE, SDFE, and TSPFE modules on the performance of TSPNet. Additionally, we validate the influence of different structures within the TDFE and SDFE modules on TSPNet. The experiments were conducted on Dataset I. Consistent with the details outlined in the implementation, during each ablation experiment, the training set and test set maintained a 70%–30% ratio, ensuring equal and balanced numbers for all classes to guarantee an equal chance level for each class. The experimental results are presented in , and a detailed analysis is provided below.",
"1) Ablation studies for TDFE : To demonstrate the effectiveness of the TDFE module, we remove the TDFE module and refer to it as TSPNet-w/o-TDFE. As shown in , when compared to TSPNet-w/o-TDFE, TSPNet exhibits a 22.3% increase in mean classification accuracy, indicating that the TDFE module, convolved in the time dimension, is effective for TSPNet. Furthermore, we replace the TDFE module with the non-residual block TDFE, EEGSym, DeepConvNet, EEGNet-8,2]. The experimental results shown in and demonstrate that TSPNet achieves the best mean accuracy on Dataset I. Compared to EEGNet-8,2, our TSPNet achieves approximately a 14.7% improvement in mean classification accuracy Quantitative analysis on the Dataset II : We evaluate the proposed TSPNet on Dataset II to demonstrate its advantages. First, we use all 61-channel EEG signals in Dataset II for experiments. The classification accuracy experimental results of 15 subjects are listed in . It can be seen from and that our TSPNet achieves an average classification accuracy of 49.7 ± 0.029, which is superior to all other comparison methods. Compared with Ofner et al., the performance of TSPNet has improved, with a relative improvement of 24.5% higher than that of 16-channel data. One possible reason is that more channels contain more spatial information. The p -values of two-sample t -test for TSPNet and other comparison methods, as shown in , , indicate a significant difference in classification accuracy between TSPNet and the other comparison methods on Dataset II.",
"The TSPNet, as proposed in this article, is a brain-computer interface is employed to visualize the source estimation of EEG data for the two datasets utilized in this article. This source estimation reveals the contributions of multiple sources to scalp EEG signals within a single cortical map. displays the EEG signal source estimation for the same action in both datasets, with a time interval of 250 ms spanning from −0.5 to 1 s. corresponds to Dataset I, while corresponds to Dataset II. This visualization is independent of TSPNet. The routines from the toolbox were employed to compute the inverse solutions for this visualization. The toolbox is open-source and available for free download at “https://github.com/aojeda/headModel.” As demonstrated in , specific areas of the cerebral cortex become activated during motor imagination, resulting in corresponding changes in EEG signals.",
"To investigate how TSPNet can successfully decode information from EEG signals, is utilized to visualize the features extracted from TSPNet, and the results are presented in . The red circles in the indicate distinct classifier patterns that can be used for differentiation. It can be observed from that the movements hand open and hand close exhibit distinct classifier patterns in the frequency ranges θ: 3–7 Hz and α : 7–13 Hz. Similarly, the movements elbow flexion and elbow extension display distinctive patterns at δ : 0.5–3 Hz, θ: 3–7 Hz, and β: 13–200 Hz, while the movements forearm supination and forearm pronation feature unique classifier patterns at δ: 0.5–3 Hz and α: 7–13 Hz. These visualization results demonstrate that the proposed framework is capable of generating distinct classifier patterns for various upper limb motor imagery categories across different frequency bands in EEG signals.",
"To elucidate the pivotal role of the TSPFE module in TSPNet, we present the transformation of feature maps before and after the TSPFE module into scalp topography maps in . It can be observed that the features after the TSPFE module are more pronounced compared to those before the TSPFE. This is attributed to the fact that TSPFE module further extracts concurrent temporal and spatial features. The features before TSPFE undergo only time dimension feature extraction from the TDFE module and spatial feature extraction from the SDFE module. Combining the results of ablation experiments in , the absence of the TSPFE module results in a 24.3% accuracy decrease for TSPNet-w/o-TSPFE compared to TSPNet, while TSPNet-w/o-TDFE and TSPNet-w/o-SDFE experience decreases of 22.3 and 22.5%, respectively. This underscores the critical importance of TSPFE in TSPNet.",
"In this work, we introduced TSPNet, a convolutional neural network classification model for motor imagery brain-computer interfaces. It enables the classification of six classes of upper limb movements based on motor imagery EEG signals. Our work provides a detailed explanation of its three constituent structures, TDFE, SDFE, and TSPFE. We conducted classification experiments on TSPNet using two datasets, comparing it with other deep learning methods [MSATNet, EEGSym, DeepConvNet, EEGNet-8,2]. The experimental results demonstrate that our proposed TSPNet outperforms the compared methods in terms of classification accuracy. Additionally, results from the two-sample t -test indicate a significant difference in accuracy between TSPNet and the compared methods. Feature visualization results, as shown in , suggest that the TSPFE module plays a crucial role in TSPNet. Before TSPFE, the TSFE module only convolves to extract time dimension features, while the SDFE module only convolves to extract spatial dimension features. TSPFE decouples the connection between time and spatial features, reducing feature redundancy. It utilizes a gating mechanism to optimize weight distribution, ultimately parallelizing time and spatial features. Furthermore, the proposed feature visualization algorithm based on signal occlusion frequency, qualitatively analyzes TSPNet's performance, showing its ability to generate different classifier patterns for various classes across different frequency bands.",
"Compared to EEGNet and MSATNet, TSPNet utilizes a signal frequency range of 0.01–200 Hz. This range is significantly broader than the signal frequency ranges used by EEGNet in movement execution. This difference can be attributed to several factors. Firstly, Ofner et al. utilized low-frequency signals (0.3–3 Hz), and the signal sampling frequency was 256 Hz, which is lower than the 500 Hz used in this paper. Secondly, and importantly, Ofner et al. employed a traditional approach involving feature extraction combined with machine learning classification patterns. The classification performance was highly dependent on the performance of the feature extraction algorithm. In contrast, TSPNet is an end-to-end deep learning model based on convolutional neural networks, where feature extraction and classification interact throughout the entire training process with shared weights, providing a distinct advantage in multi-class tasks.",
"In terms of limitations, despite the superior performance of the proposed TSPNet compared to other methods used in this paper, the accuracy in the six-class motor imagery task remains relatively low. Under the current research results, it is insufficient to generate precise and error-free control signals for the motion control of neural prosthetics or robotic arms. Several factors contribute to this limitation. Firstly, the intrinsic complexity and variability of EEG signals make achieving high decoding accuracy challenging. Secondly, EEG signals are generated by electrical potentials from different regions of the brain but are measured through electrodes placed on the scalp. Due to the conductivity and geometric properties of the head tissues, the recorded signals are spatially ambiguous and cannot accurately represent the potential neural sources. To address the current limitation of low classification accuracy, in future research, we will explore the integration of transfer learning into the classification of motor imagery EEG signals to enhance the performance of the classification model. Simultaneously, we will develop a continuous decoding strategy to further improve the classification accuracy of motor imagery tasks through multiple consecutive decoding steps.",
"In this article, the TSPNet is proposed to achieve intention recognition for multiclass upper limb motor imagery. Ablation studies demonstrate the necessity of each module in the proposed TSPNet. Our proposed TSPNet achieved a classification accuracy of 49.1% ± 0.043 in Dataset I and 49.7% ± 0.029 in Dataset II for 6 categories of upper limb motor imagery EEG signals. Comparison results with other deep learning methods demonstrate the superior performance of the TSPNet model. Subsequently, we introduce a feature visualization algorithm based on signal occlusion frequency to qualitatively analyze TSPNet. These visualization results demonstrate that the proposed TSPNet is capable of generating distinct classifier patterns for various upper limb motor imagery categories across different frequency bands in EEG signals. The results show that the proposed TSPNet can achieve intention recognition for multiple category upper limb motor imagery, which is of special significance in non-invasive BCI applications and provides the possibility to increase the degrees of freedom for devices controlled by BCI, such as robots, manipulators, or nerve rehabilitation devices.",
"The datasets presented in this study can be found in online repositories. The names of the repository/repositories and accession number(s) can be found at: https://dx.doi.org/10.21227/8qw6-f578.",
"JB: Data curation, Methodology, Validation, Visualization, Writing—original draft. MC: Conceptualization, Project administration, Supervision, Writing—review & editing. GW: Data curation, Formal analysis, Writing—review & editing. XG: Data curation, Formal analysis, Writing—review & editing."
] |
PMC10372701
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JAMA Network Open
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Low-Dose Aspirin and the Risk of Stroke and Intracerebral Bleeding in Healthy Older People
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26-07-2023
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The secondary analysis of a randomized clinical trial investigates the effect of low-dose aspirin on incidence of ischemic stroke and intracranial bleeding among healthy older people.
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[
"Aspirin is an antiplatelet agent that has been used in low doses",
"People aged 70 years or older. A total of 9525 participants were allocated to aspirin and 9589 participants to placebo. At baseline, randomized treatment groups were well matched in demographic and risk factors for stroke.^(21)",
"During follow-up, the rate of intracranial events including stroke was low, at 5.8 per 1000 person-years of follow-up A first stroke was experienced by 398 individuals. Of these events, 53 strokes were fatal, including 22 strokes, we found no evidence of a differential effect of aspirin across subgroups of age, sex, smoking, diabetes, dyslipidemia, frailty category, hypertension, or country. There were no associations between aspirin and ischemic stroke subtype.",
"Results for hemorrhagic stroke and intracranial bleeding based on anatomical location are displayed in the . Overall, there were 86 hemorrhagic strokes between individuals assigned to aspirin or placebo was not statistically significant. In absolute terms, this resulted from an excess of 29 first intracranial bleeding events among individuals assigned to aspirin, which exceeded the decrease of 20 fewer ischemic strokes. As with ischemic stroke, we found no evidence of a differential effect of aspirin on the risk of having a first intracranial bleeding event across subgroups, including frailty category.",
"shows the unadjusted model of ischemic stroke and hemorrhagic stroke subtypes during the course of the study. For first ischemic stroke, the model yielded an HR of 0.89 was driven by the increased risk of upper gastrointestinal bleeding with aspirin compared with placebo, as previously found.",
"Overall, results are in keeping with meta-analyses reported by the Antithrombotic Trialists’ Collaboration in 2009,^(9) US Preventive Services Task Force (USPSTF) in 2016,^(10) and a 2020 meta-analysis by Judge et al^(8) summarizing results of 11 primary prevention trials, including 3 major trials published in 2018.^(8) Most patients included in these reports were younger than those in ASPREE.^(8) Consistent findings across these studies were a small reduction of ischemic events accompanied by an increase in hemorrhagic events. Unlike in our study, the absolute decrease in ischemic strokes substantially outweighed the increase in hemorrhagic events, and this has probably resulted in a discounting of intracerebral bleeding as an important component of the risk-benefit trade-off in younger populations.",
"The lack of benefit and potential risks from aspirin in primary stroke prevention provide further evidence in support of the recently published draft recommendation of the USPSTF against the routine prescribing of low-dose aspirin as a primary prevention measure, especially in older persons.^(34) Clinicians should be aware that among older individuals prone to falls, risks of intracerebral bleeding with aspirin may be greater than was apparent in this trial. Our results are also cautionary with regard to the inclusion of aspirin in a polypill to prevent cardiovascular disease in healthy older adults.^(35 , 36) Studies of newer antiplatelet therapies, such as clopidogrel, ticagrelor, or prasugrel, have not been undertaken in a primary prevention setting and should not yet be considered as alternatives to aspirin for this indication.",
"Strengths of this data derive from its size coupled with virtually complete follow-up and systematic adjudication of stroke events by specialist clinicians. The study also has several limitations, including fewer than expected stroke and bleeding events occurring during follow-up and the lack of detailed investigation of stroke occurring in some older participants. Results are mainly generalizable to a White population (participation by individuals in racial and ethnic minority groups was largely limited to the US, where Black and Hispanic people aged ≥65 years were purposively recruited) with routine access to optimal blood pressure and lipid control. The balance of risks and benefits found in this study is not applicable to the use of aspirin for secondary prevention and may not be applicable to certain subgroups at substantially higher risk of ischemic stroke.",
"In this secondary analysis of a randomized clinical trial of older adults, there was no statistically significant benefit from aspirin in preventing stroke or any conventional stroke etiological subtype. However, aspirin significantly increased the overall risk of intracranial bleeding. These data support the recommendation of the USPSTF that low-dose aspirin should not be prescribed for primary prevention in healthy older adults."
] |
PMC10152627
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Journal of Neuroinflammation
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Role of macrophage autophagy in postoperative pain and inflammation in mice
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02-05-2023
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Background Postoperative pain and inflammation are significant complications following surgery. Strategies that aim to prevent excessive inflammation without hampering natural wound-healing are required for the management of postoperative pain and inflammation. However, the knowledge of the mechanisms and target pathways involved in these processes is lacking. Recent studies have revealed that autophagy in macrophages sequesters pro-inflammatory mediators, and it is therefore being recognized as a crucial process involved in regulating inflammation. In this study, we tested the hypothesis that autophagy in macrophages plays protective roles against postoperative pain and inflammation and investigated the underlying mechanisms. Methods Postoperative pain was induced by plantar incision under isoflurane anesthesia in mice lacking macrophage autophagy (Atg5flox/flox LysMCre +) and their control littermates (Atg5flox/flox). Mechanical and thermal pain sensitivity, changes in weight distribution, spontaneous locomotor activity, tissue inflammation, and body weight were assessed at baseline and 1, 3, and 7 days after surgery. Monocyte/macrophage infiltration at the surgical site and inflammatory mediator expression levels were evaluated. Results Atg5flox/flox LysMCre + mice compared with the control mice exhibited lower mechanical and thermal pain thresholds and surgical/non-surgical hindlimb weight-bearing ratios. The augmented neurobehavioral symptoms observed in the Atg5flox/flox LysMCre + mice were associated with more severe paw inflammation, higher pro-inflammatory mediator mRNA expression, and more monocytes/macrophages at the surgical site. Conclusion The lack of macrophage autophagy augmented postoperative pain and inflammation, which were accompanied by enhanced pro-inflammatory cytokine secretion and surgical-site monocyte/macrophage infiltration. Macrophage autophagy plays a protective role in postoperative pain and inflammation and can be a novel therapeutic target. Supplementary Information The online version contains supplementary material available at 10.1186/s12974-023-02795-w.
|
[
"Postoperative pain is one of the most significant post-surgical complications and can delay functional recovery and impair patients’ quality of life. Inflammation plays crucial roles in the pathophysiology of postoperative pain. Once tissue damage occurs from surgical intervention, inflammatory cells proliferate at the surgical site, producing inflammatory mediators and causing tissue inflammation [ , ]. At the site of inflammation, the so-called inflammatory soup—a wide array of signaling molecules, such as cytokines, chemokines, and neurotransmitters—is generated, which triggers inflammatory pain [ ]. Conversely, inflammation also functions as a protective innate immune response that is essential for normal wound-healing and tissue remodeling [ ]. Therefore, a simple anti-inflammatory strategy may not be ideal for the treatment of postoperative pain, and often raises concerns regarding adverse effects, such as delayed wound-healing [ ]. Non-steroidal anti-inflammatory drugs, local anesthetics, and opioids have been widely used to treat postoperative pain; however, many of these drugs have immunosuppressive effects and can delay tissue recovery [ – ]. Therefore, strategies that aim to prevent excessive inflammation without hampering natural wound-healing, rather than those that simply suppress inflammation, are required for the management of postoperative pain and inflammation. However, the knowledge of the mechanisms and target pathways involved in these processes is lacking.",
"Autophagy, an intracellular self-degradation system, is an essential biological process that removes unnecessary cytosol, cytoplasmic organelles, and even microbes from cells [ – ]. Recent studies have revealed that autophagy in macrophages sequesters pro-inflammatory mediators, and it is therefore being recognized as a crucial process involved in regulating inflammation in various diseases, including atherosclerosis [ , ], inflammatory bowel disease [ ], uveitis [ ], infection [ – ], peripheral neuronal injury [ ], and brain ischemia [ ]. Considering that macrophages are key cells in the generation and resolution of inflammatory pain [ , , ], autophagy in macrophages can be expected to play pivotal roles in postoperative pain and inflammation as well as their resolution, and is therefore a potential therapeutic target.",
"This study aimed to investigate the potential involvement and protective roles of macrophage autophagy in postoperative pain and inflammation, and to describe the underlying mechanisms.",
"All experiments were conducted in accordance with the National Institutes of Health, National Academy of Science, and International Association for the Study of Pain guidelines for the care and use of laboratory animals. The experimental protocol was reviewed and approved by the University of Yamanashi Animal Care Committee and LysMCre. Atg5 f/f littermates served as the controls. C57BL/6J mice were purchased from Japan SLC were gently applied from below for 1 s. Positive responses were defined as flinching, shaking, licking, or retraction of the leg, representing a clear nociceptive perception to the mechanical stimulus [ ]. The experiments started with the 0.6-g filament, and the up–down method was used to determine the 50% withdrawal threshold [ , ].",
"Thermal withdrawal latencies were assessed using Hargreaves method [ ]. Briefly, animals were placed in the same plastic chamber used for the von Frey test on an elevated glass platform preheated at 29–30 °C. A radiant heat source. When a mouse was in a stable position for at least 3 s, the weight-bearing of the left and right hindlimbs was recorded, and the ratio was calculated. Trials were repeated three times, and mean values were recorded.",
"Spontaneous locomotor activity after surgery was assessed using the open-field test as previously described [ , ]. Animals were set loose in a 50 × 50 × 50-cm plastic chamber with 4 × 4 grid lines on the floor, making a total of 25 10 × 10 cm squares. The number of lines crossed with all paws in 5 min was recorded.",
"The mouse paws were dissected, and 20 µm-thick frozen sections were prepared using a cryostat, interleukin 6. The levels of the inflammatory mediators are reported in terms of the fold increase with the levels on the contralateral side of the Atg5 f/f mice defined as 1.0.",
"Statistical analysis was conducted using GraphPad Prism 9. Furthermore, Atg5 cKO mice exhibited significant SQSTM1/p62 accumulation. Autophagy deficiency in ATG5 cKO mice macrophages was also confirmed using immunofluorescence analysis. As shown in Fig. D and E, LC3 immuno-staining density was significantly lower in serum-starved macrophages from ATG5 cKO mice than in those from Atg5 f/f mice Similar results were confirmed in female mice. Mechanical and thermal sensitivities in the contralateral paws were not affected by the deficient macrophage autophagy. Although the weight-bearing ratio values were not significantly different between the groups on day 1, n = 6 each, P < 0.01, CD11c: 26 ± 6 vs. 84 ± 16 cells / 0.1mm^(2), n = 6 each, P < 0.05, Day3—Iba1: 31 ± 5 vs. 57 ± 10 cells / 0.1 mm^(2), P < 0.05, CD11c: 13 ± 3 vs. 38 ± 7 cells / 0.1 mm^(2), P < 0.01). In contrast, Atg5 cKO and Atg5 f/f mice showed similar numbers of CD206-positive cells in the dermis. In contrast, the mRNA levels of anti-inflammatory mediators (IL-10 and TGF-β1) were not significantly different between groups, demonstrating a shift toward the pro-inflammatory state in the macrophage autophagy-deficient Atg5 cKO mice."
] |
PMC10995625
|
Microbial Genomics
|
Optimising machine learning prediction of minimum inhibitory concentrations in Klebsiella pneumoniae
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26-03-2024
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Abstract Minimum Inhibitory Concentrations (MICs) are the gold standard for quantitatively measuring antibiotic resistance. However, lab-based MIC determination can be time-consuming and suffers from low reproducibility, and interpretation as sensitive or resistant relies on guidelines which change over time. Genome sequencing and machine learning promise to allow in silico MIC prediction as an alternative approach which overcomes some of these difficulties, albeit the interpretation of MIC is still needed. Nevertheless, precisely how we should handle MIC data when dealing with predictive models remains unclear, since they are measured semi-quantitatively, with varying resolution, and are typically also left- and right-censored within varying ranges. We therefore investigated genome-based prediction of MICs in the pathogen Klebsiella pneumoniae using 4367 genomes with both simulated semi-quantitative traits and real MICs. As we were focused on clinical interpretation, we used interpretable rather than black-box machine learning models, namely, Elastic Net, Random Forests, and linear mixed models. Simulated traits were generated accounting for oligogenic, polygenic, and homoplastic genetic effects with different levels of heritability. Then we assessed how model prediction accuracy was affected when MICs were framed as regression and classification. Our results showed that treating the MICs differently depending on the number of concentration levels of antibiotic available was the most promising learning strategy. Specifically, to optimise both prediction accuracy and inference of the correct causal variants, we recommend considering the MICs as continuous and framing the learning problem as a regression when the number of observed antibiotic concentration levels is large, whereas with a smaller number of concentration levels they should be treated as a categorical variable and the learning problem should be framed as a classification. Our findings also underline how predictive models can be improved when prior biological knowledge is taken into account, due to the varying genetic architecture of each antibiotic resistance trait. Finally, we emphasise that incrementing the population database is pivotal for the future clinical implementation of these models to support routine machine-learning based diagnostics.
|
[
"The scripts used to run and fit the models can be found athttps://github.com/gbatbiff/Kpneu_MIC_prediction. The Illumina sequences from Thorpe et al . are available from the European Nucleotide Archive under accession PRJEB27342 . All the other strains are available on https://www.bv-brc.org/ database.",
"Klebsiella pneumoniae is a leading cause of hospital and community acquired infections worldwide, highly contributing to the global burden of antimicrobial resistance). However, synergistic effects such as the inactivation of an outer membrane protein or overexpression of efflux pumps can occur, in resistance associated to polygenic traits [ ], where effect sizes greatly vary across the involved genes. Another example of synergistic effects is the epistatic interaction between pbp loci encoding for the penicillin-binding proteins, a measure of the concentration at which the antibiotic inhibits bacterial growth in standard culture conditions. Several MIC measuring methods exist, differing by the antibiotics and range of concentrations tested. For example, solid-based methods have an extended range of MICs compared to broth dilution, but are long and costly, and are limited to testing for one antibiotic at a time. MIC interpretation is based on threshold values called breakpoints, typically decided for each pathogen-antibiotic combination by experts at international organisations such as EUCAST have also been used for producing such catalogues [ ].",
"The application of supervised-machine learning has been introduced in genome-based diagnostics to build more accurate, although potentially less interpretable, predictors of antimicrobial susceptibility [ ]. However, model interpretability is key in the clinical context where the detection of specific genetic determinants of resistance is expected in order to provide confidence in the results’ accuracy. In addition, knowing which variants are selected from the model to infer the prediction is pivotal in the context of AMR [ ], as the use of black-box algorithms offers no insight into how the model produces its predictions. Therefore, the use of black-box algorithms has received only limited practical interest in clinical settings.",
"Indeed, prediction of resistance has exploited several interpretable machine learning models such as Gradient Boosting [ ], Random Forests [ ] and regularised linear regression [ ]. These models already achieved promising results in the prediction of quantitative traits in several bacterial species such as M. tuberculosis [ ], and nontyphoidal Salmonella [ ].",
"However, benchmarking these models is challenging since their accuracy can be affected by population structure and the different genetic architecture of each resistance trait [ ], potentially leading to false positive associations in highly clonal populations [ ]. Another limitation in these studies is caused by the specifics of MIC measurement and interpretation, which may affect the prediction accuracy and genotype-phenotype correlation [ ]. Due to the semi-quantitative nature of MICs and the limits on varying antibiotic-step concentrations, they can be considered censored, specifically right-censored, and those for David et al ., using lyophilized custom plates.",
"To preserve the complex genetic architecture of the K. pneumoniae species, we simulated quantitative traits based on real observed genotypes. To generate the data for the gene-based trait simulation, gene sequences were annotated using Prokka v1.14.6 [ ] and then clustered with Panaroo v1.2.8 [ ] in moderate mode, giving a pan-genome with a total of 35 380 genes. The presence absence matrix obtained from Panaroo v1.2.8 was converted to a VCF format by selecting the loci with minor allele frequency was high, as recommended for highly-recombinant species [ ]. This filtering step prevents strongly associated loci from being included in the phenotype simulation as causal markers.",
"To evaluate the predictive performance of each statistical model, quantitative MIC phenotypes were generated from the real genotypes in four different ways. Both genes and SNPs were used in the simulations.",
"In this bacterial population there are between 1–10 million unitigs, and it was simply computationally infeasible for us to complete this analysis with current Elastic Net and Random Forest implementations – the contribution of a specific locus to the genetic variance of the trait, and narrow-sense heritability, bla _(OXA) and bla _(KPC) involved in beta-lactam resistance were chosen to be causative of the trait.",
"A polygenic simulation selected 1000 random SNPs across the genome with same [ ].",
"A homoplastic simulation [ ] selected one causal SNP exhibiting homoplasy. Homoplastic sites were detected with HomoplasyFinder v0.9 [ ]. The SNP-based phylogeny required as input to HomoplasyFinder was inferred with IQ-tree v2.2.0 [ ], choosing the General Time Reversible, was chosen according to the consistency index and homoplasy values of the filtered MICs were used as labels for all machine learning tasks.",
"We used two machine learning models: Elastic Net and Random Forest. These were chosen due to their interpretability and scalability as well as accuracy [ ]. In addition, both these models allow us to apply population structure correction, as explained below.",
"To evaluate the performance of statistical models in detecting the causal markers, Elastic Net and Random Forest were tested on the simulated data, using independently two presence-absence matrices as input, coreSNPs- and genes-based respectively. Both regression and classification setups were used, allowing us to highlight how the framing of statistical problems affected the predictive accuracy of the models.",
"All the analyses run using Elastic Net and Random Forest were performed by splitting the dataset randomly into 70 % training and 30 % testing.",
"Regression and multinomial classification performance was assessed using the proportion of variance explained.",
"Balanced accuracy provides a clear interpretation of the model performance by computing the average of recall and L2 and their predictive accuracy tested on the held out test data. The most accurate, or most sparse model within an accuracy range, can be used to select the best hyperparameter. This procedure is automated within ‘glmnet’ package. It has previously been recommended that population-structure-based subclusters are used as the folds [ ]. We also show that using previous recommendations for a preset alpha, using as number of tests the amount of SNPs detected. Although Bonferroni is a highly conservative method that potentially suffers from false negative rate when variants are not independent, it works properly when the selected loci are not in strong linkage disequilibrium, i.e. LD 0.6.",
"Due to the complex dynamics of bacterial populations. This matrix accounts for genetic relatedness between strains and is included in the regression as a random effect.",
"In order to generate multiple realistic quantitative traits which account for different genetic scenarios, a total of four simulations were carried out, accounting for oligogenic, homoplastic and polygenic effects using two genes with fixed effect sizes, both using binary or continuous phenotypes [ ]. Despite these organisms being quite different, the heritability related to AMR is expected to be sizable across species, as the converse that resistance being caused entirely by non-genomic changes is unlikely.",
"We noted that different effect sizes used in this simulation do not significantly affect the density distributions of the simulated phenotypes, with heritability having a more important effect over this range. Since this preliminary analysis on our dataset confirmed that the separation of the trait by marker started at h² =~0.6, the quantitative traits through the four simulations were generated starting from high levels of h² .",
"Most machine learning methods rely on the assumption that observations and predictors are identically and independently distributed, which is rarely the case with genomic data, particularly highly structured bacterial populations. Therefore, accounting for population structure when using these models is recommended to avoid false positive and spurious associations [ ].",
"In this work, we benchmarked Elastic Net, Random Forest, interpretable and flexible machine learning methods able to handle high dimensional data where P N , both with the capability for regression and classification. In addition, Fast-LMM. Our analysis showed a decrease of the accuracy, with further decreases with more bins. For this reason, we also assessed the off-by-one prediction accuracy – discussed below – allowing us to improve the models interpretability whether the range of antibiotic-step concentrations is broader.",
"Specifically, when the binned quantitative simulated traits without applying the censoring were used, the Elastic Net and Random Forest perform similarly in the homoplasic simulation, where bACC range of Elastic Net was 0.55–0.88. Although we observed an increasing in accuracy only at h² =0.6, especially in case of two bins in the oligogenic, we observed that the Random Forest achieved a higher accuracy in all simulations. Albeit also the Elastic Net gained an improvement of the prediction accuracy where the traits were not censored, as previous studies have already assessed [ ].",
"In this setting, we considered 4, 6, 8 and 10 binned phenotypes of the simulations. Here, we calculated the performance using the R² value. Simultaneously we estimated the h² , since it represents the proportion of variance that can be attributed to the variation of genetic effects and thus the equivalent to the R² in regression analysis.",
"shows the performance of the two methods over the two levels of h² , where the dashed lines indicated the h² levels used to generate the quantitative simulated MICs. We pinpointed that the R² achieved by both the models increased overall proportionally with the number of the bins up to continuous distribution, as expected.",
"There was an overlapping trend between the models in the homoplasic and oligogenic, albeit the Random Forest exhibited an overall better fit compared with Elastic Net except for the oligogenic simulation, since we cannot vary the genetic effects such as effect size distribution and homoplasy. Therefore, we assessed the model performances in terms of accuracy by cross validation.",
"Since the K. pneumoniae strains were not always tested for the same antibiotics across the three datasets, we selected three antibiotic classes of interest where the MICs were largely available. Thus, Fluoroquinolones, Aminoglycosides and Beta-lactams were considered and a representative drug for each class was selected by including Gentamicin.",
"Dealing with MICs framed as classification, Elastic Net and Random Forest showed comparable balanced accuracy when dealing with Gentamicin, Meropenem and Piperacillin/Tazobactam, while in case of Ciprofloxacin the accuracy was higher when using the Elastic Net model. However, once the accuracy of classification prediction was measured by allowing one predicted class higher or lower as correct, we observed an increased performance in the accuracy of Elastic Net while the Random Forest did not exhibit any significant improvement, in contrast with what we observed in the simulations.",
"When the MICs were framed as regression, the Random Forest showed a better performance compared to the Elastic Net for all the antibiotics. Therefore the regression model could not possibly fit as if it dealt with a standard normal distribution, as expected.",
"In addition, both the Random Forest and Elastic Net showed better performance on the R² train set compared to the R² test set, suggesting that these models are prone to overfitting.",
"The results on real MICs highlighted how the classification model outperforms the regression one, with the only exemption of Random Forest when the prediction of Ciprofloxacin was assessed, showing an overlapping accuracy between the two cases.",
"We also benchmark Elastic Net, Random Forest and Pyseer for the h² estimation. The h² associated with antibiotic resistance is expected to be high, on the basis that the trait is largely determined by highly penetrant additive genetic variants directly causal for the resistance mechanism [ ]. Indeed, the h² estimation of the three models on Ciprofloxacin, Gentamicin and Piperacillin/Tazobactam indicates these traits as highly and moderately penetrant, whilst the estimated h² for Meropenem exhibits a lower level. These results suggested how the different intervals of estimated h² can be associated with the location of genetic causative variants of the antibiotic resistance. Indeed, when the resistance is mainly associated with genes carried on plasmids, the genetic variation can be poorly accounted in our model [ ], as possible implementation within a Bayesian framework via an ordinal regression model.",
"In conclusion, collections of high-quality genomes are increasingly populating global databases, and availability of MIC data would be equally recommended, possibly specifying details of the phenotypic test used. Subsequently, laboratory tests able to increase the range of antibiotic-step concentrations (e.g. E-test) should be considered – reducing the level of censored data – when building these models. Indeed, while it is easier to indicate a binary phenotype, this interpretation is not consistent over time, and results in permanent information loss. Having more information-rich phenotype data would allow more modelling possibilities, and especially as datasets grow may help improve prediction accuracy in future, as the number of samples increases far beyond what we have been able to study here."
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