Knowledge, perception, and attitudes of medical students towards antimicrobial resistance and stewardship: an observational cross-sectional study from Palestine.

BACKGROUND: Antimicrobial resistance is a global health concern that contributes to significant mortality and morbidity. This study investigated knowledge, perceptions, and attitudes of medical students in Palestinian universities towards antimicrobial resistance and stewardship. The study also investigated associations between variables of students with their knowledge, perceptions, and attitudes. METHODS: A questionnaire was used in this cross-sectional study. Medical students in Palestinian universities were surveyed in this study. In addition to the demographic variables of the medical students, the questionnaire measured knowledge, perceptions, and attitudes of medical students in Palestinian universities towards antimicrobial resistance and stewardship. RESULTS: In this study, 384 medical students returned complete questionnaires. Of the medical students, 269 (70.1%) were female, 215 (56.0%) lived in urban areas, and 244 (63.5%) were in their clinical training years. Medical students in the clinical phase demonstrated higher knowledge about microbial resistance compared to preclinical students as evidenced by a mean score of 89.7 ± 15.9 compared to 74.0 ± 26.4, respectively (p < 0.05). Similarly, clinical students displayed higher score regarding antimicrobial resistance perception, with a mean score of 85.7 ± 15.6, contrasted with 72.6 ± 24.1 among preclinical students. In terms of knowledge pertaining to antimicrobial stewardship, clinical students scored higher with a mean of 63.4 ± 28.5 compared to 54.5 ± 31.5 among preclinical students. Regarding attitudes, clinical students also demonstrated a higher mean score of 67.6 ± 22.6 in contrast to 61.1 ± 24.6 among preclinical students. CONCLUSION: The medical students are the future workforce of physicians in any healthcare system. Therefore, increasing knowledge of the medical students about and how to combat antimicrobial resistance can help save lives and improve patient outcomes. More studies are needed to find the best ways to increase knowledge, perceptions, and attitudes of medical students towards antimicrobial resistance and antimicrobial stewardship.

Correlative SICM-FCM reveals changes in morphology and kinetics of endocytic pits induced by disease-associated mutations in dynamin.

Dynamin 2 (DNM2) is a GTP-binding protein that controls endocytic vesicle scission and defines a whole class of dynamin-dependent endocytosis, including clathrin-mediated endocytosis by caveoli. It has been suggested that mutations in the DNM2 gene, associated with 3 inherited diseases, disrupt endocytosis. However, how exactly mutations affect the nanoscale morphology of endocytic machinery has never been studied. In this paper, we used live correlative scanning ion conductance microscopy (SICM) and fluorescence confocal microscopy (FCM) to study how disease-associated mutations affect the morphology and kinetics of clathrin-coated pits (CCPs) by directly following their dynamics of formation, maturation, and internalization in skin fibroblasts from patients with centronuclear myopathy (CNM) and in Cos-7 cells expressing corresponding dynamin mutants. Using SICM-FCM, which we have developed, we show how p.R465W mutation disrupts pit structure, preventing its maturation and internalization, and significantly increases the lifetime of CCPs. Differently, p.R522H slows down the formation of CCPs without affecting their internalization. We also found that CNM mutations in DNM2 affect the distribution of caveoli and reduce dorsal ruffling in human skin fibroblasts. Collectively, our SICM-FCM findings at single CCP level, backed up by electron microscopy data, argue for the impairment of several forms of endocytosis in DNM2-linked CNM.-Ali, T., Bednarska, J., Vassilopoulos, S., Tran, M., Diakonov, I. A., Ziyadeh-Isleem, A., Guicheney, P., Gorelik, J., Korchev, Y. E., Reilly, M. M., Bitoun, M., Shevchuk, A. Correlative SICM-FCM reveals changes in morphology and kinetics of endocytic pits induced by disease-associated mutations in dynamin.

Montelukast, current indications and prospective future applications.

INTRODUCTION: Montelukast is recommended for the treatment of asthma, exercise -induced bronchospasm and allergic rhinitis. Several trials demonstrated potential therapeutic effects in other respiratory conditions, and different animal-model-based studies explored potential pharmacological actions in non-respiratory conditions. AREAS COVERED: Clinical investigations on the pharmacotherapeutic effects of montelukast, in addition to in-vivo studies on animal models of non-respiratory diseases. The data discussed in this review were mainly obtained from clinical randomized trials, real-life studies, and studies based on animal models as approve of concept. As a condition, all of the discussed articles were published in journals cited by Pubmed. Expert commentary: The current clinical data are in favor of montelukast use in the management of chronic asthma as an add-on or alternative therapy to the inhaled corticosteroids. Further clinical trials are required to confirm the effectiveness and feasibility of montelukast for the treatment of conditions other than the current clinical indications.

A truncating SCN5A mutation combined with genetic variability causes sick sinus syndrome and early atrial fibrillation.

BACKGROUND: Mutations in the SCN5A gene, encoding the α subunit of the cardiac Na(+) channel, Nav1.5, can result in several life-threatening arrhythmias. OBJECTIVE: To characterize a distal truncating SCN5A mutation, R1860Gfs*12, identified in a family with different phenotypes including sick sinus syndrome, atrial fibrillation (AF), atrial flutter, and atrioventricular block. METHODS: Patch-clamp and biochemical analyses were performed in human embryonic kidney 293 cells transfected with wild-type (WT) and/or mutant channels. RESULTS: The mutant channel expressed alone caused a 70% reduction in inward sodium current (INa) density compared to WT currents, which was consistent with its partial proteasomal degradation. It also led to a negative shift of steady-state inactivation and to a persistent current. When mimicking the heterozygous state of the patients by coexpressing WT and R1860Gfs*12 channels, the biophysical properties of INa were still altered and the mutant channel α subunits still interacted with the WT channels. Since the proband developed paroxysmal AF at a young age, we screened 17 polymorphisms associated with AF risk in this family and showed that the proband carries at-risk polymorphisms upstream of PITX2, a gene widely associated with AF development. In addition, when mimicking the difference in resting membrane potentials between cardiac atria and ventricles in human embryonic kidney 293 cells or when using computer model simulations, R1860Gfs*12 induced a more drastic decrease in INa at the atrial potential. CONCLUSION: We have identified a distal truncated SCN5A mutant associated with gain- and loss-of-function effects, leading to sick sinus syndrome and atrial arrhythmias. A constitutively higher susceptibility to arrhythmias of atrial tissues and genetic variability could explain the complex phenotype observed in this family.

Dominant-negative effect of SCN5A N-terminal mutations through the interaction of Na(v)1.5 α-subunits.

AIMS: Brugada syndrome (BrS) is an autosomal-inherited cardiac arrhythmia characterized by an ST-segment elevation in the right precordial leads of the electrocardiogram and an increased risk of syncope and sudden death. SCN5A, encoding the cardiac sodium channel Na(v)1.5, is the main gene involved in BrS. Despite the fact that several mutations have been reported in the N-terminus of Na(v)1.5, the functional role of this region remains unknown. We aimed to characterize two BrS N-terminal mutations, R104W and R121W, a construct where this region was deleted, ΔNter, and a construct where only this region was present, Nter. METHODS AND RESULTS: Patch-clamp recordings in HEK293 cells demonstrated that R104W, R121W, and ΔNter abolished the sodium current I(Na). Moreover, R104W and R121W mutations exerted a strong dominant-negative effect on wild-type (WT) channels. Immunocytochemistry of rat neonatal cardiomyocytes revealed that both mutants were mostly retained in the endoplasmic reticulum and that their co-expression with WT channels led to WT channel retention. Furthermore, co-immunoprecipitation experiments showed that Na(v)1.5-subunits were interacting with each other, even when mutated, deciphering the mutation dominant-negative effect. Both mutants were mostly degraded by the ubiquitin-proteasome system, while ΔNter was addressed to the membrane, and Nter expression induced a two-fold increase in I(Na). In addition, the co-expression of N-terminal mutants with the gating-defective but trafficking-competent R878C-Na(v)1.5 mutant gave rise to a small I(Na). CONCLUSION: This study reports for the first time the critical role of the Na(v)1.5 N-terminal region in channel function and the dominant-negative effect of trafficking-defective channels occurring through α-subunit interaction.

An alternative mechanism of clathrin-coated pit closure revealed by ion conductance microscopy.

Current knowledge of the structural changes taking place during clathrin-mediated endocytosis is largely based on electron microscopy images of fixed preparations and x-ray crystallography data of purified proteins. In this paper, we describe a study of clathrin-coated pit dynamics in living cells using ion conductance microscopy to directly image the changes in pit shape, combined with simultaneous confocal microscopy to follow molecule-specific fluorescence. We find that 70% of pits closed with the formation of a protrusion that grew on one side of the pit, covered the entire pit, and then disappeared together with pit-associated clathrin-enhanced green fluorescent protein (EGFP) and actin-binding protein-EGFP (Abp1-EGFP) fluorescence. This was in contrast to conventionally closing pits that closed and cleaved from flat membrane sheets and lacked accompanying Abp1-EGFP fluorescence. Scission of both types of pits was found to be dynamin-2 dependent. This technique now enables direct spatial and temporal correlation between functional molecule-specific fluorescence and structural information to follow key biological processes at cell surfaces.