An objective tool for quantifying atrial fibrillation substrate in rats.

The utility of rodents for research related to atrial fibrillation (AF) is growing exponentially. However, the obtained arrhythmic waveforms are often mixed with ventricular signals and the ability to analyze regularity and complexity of such events is limited. Recently, we introduced an implantable quadripolar electrode adapted for advanced atrial electrophysiology in ambulatory rats. Notably, we have found that the implantation itself leads to progressive atrial remodeling, presumably because of mechanical loading of the atria. In the present study, we developed an algorithm to clean the atrial signals from ventricular mixing and thereafter quantify the AF substrate in an objective manner based on waveform complexity. Rats were sequentially examined 1-, 4-, and 8-wk postelectrode implantation using a standard AF triggering protocol. Preburst ventricular mixing was sampled and automatically subtracted based on QRS detection in the ECG. Thereafter, the "pure" atrial signals were analyzed by Lempel-Ziv complexity algorithm and a complexity ratio (CR) was defined for each signal by normalizing the postburst to the preburst values. Receiver operating characteristic (ROC) curve analysis indicated an optimal CR cutoff of 1.236 that detected irregular arrhythmic events with high sensitivity (94.5%), specificity (93.1%), and area under the curve (AUC) (0.96, 95% confidence interval, 0.945-0.976). Automated and unbiased analysis indicated a gradual increase in signal complexity over time with augmentation of high frequencies in power spectrum analysis. Our findings indicate that CR algorithm detects irregularity in a highly efficient manner and can also detect the atrial remodeling induced by electrode implantation. Thus, CR analysis can strongly facilitate standardized AF research in rodents.NEW & NOTEWORTHY Rodents are increasingly used in AF research. However, because of technical difficulties including atrial waveform mixing by ventricular signals, most studies do not discriminate between irregular (i.e., AF) and regular atrial arrhythmias. Here, we develop an unbiased computerized tool to "pure" the atrial signals from ventricular mixing and thereafter analyze AF substrate based on the level of irregularity in an objective manner. This novel tool can facilitate standardized AF research in rodents.

Burnout in Israeli medical students: a national survey.

INTRODUCTION: Professional burnout is characterized by loss of enthusiasm for work, cynicism, and a low sense of personal efficacy. Burnout may adversely affect medical professionalism. Burnout is common in clinicians and varying rates have been reported in medical students. No data exist regarding the prevalence of burnout among Israeli medical students. The aims of this study were to assess the rate of burnout in Israeli medical students and to identify students who were particularly susceptible to burnout. METHODS: A cross-sectional questionnaire design was employed, gathering data from medical students in all years of study across three medical schools. Burnout was measured using the Maslach Burnout Inventory Student Survey (MBI-SS), translated into Hebrew. RESULTS: Of the 2160 students in the participating medical schools, 966 (44.7%) completed MBI-SS and demographic questionnaires. The overall burnout rate was 50.6%. Multivariate logistic regression analysis yielded that female gender, age under 25, advanced year of study, studying at a specific medical school and not being a parent are all significantly correlated with higher levels of burnout. CONCLUSIONS: A high rate of burnout was found. The identification of young women who are not parents during advanced years of studies as being at-risk is important, in order to guide the development of burnout prevention interventions.

Exploring the Trends of Acute Appendicitis Following Recovery or Vaccination From COVID-19.

INTRODUCTION: The relationship that vaccination against corona virus disease 19 (COVID-19) or recovery from the acute form of the illness may have with the incidence or severity of acute appendicitis (AA) has not been explored. The aim of this study was to evaluate this relationship. METHODS: A single centre retrospective study of all consecutive adult patients presenting with AA in the 6 mo after the initiation of a national vaccination program was performed. The presenting characteristics and pathological data of patients who had either been vaccinated against or recovered from COVID-19 were compared with those who had not. In addition, historical data from the equivalent period 12 and 24 mo beforehand was also extracted. The incidence of AA was compared between each of these time-frames. RESULTS: Of the 258 patients initially identified, 255 were included in the analysis of which 156 had either been vaccinated and/or recovered from COVID-19 (61.2%) whilst 99 (38.8%) patients had not. When comparing these two groups, there were no significant differences in the presenting characteristics, operative findings or postoperative courses. There was also no significant change in the incidence of AA when comparing the study dates with historical data (median weekly incidence of AA 8.0 versus 8.0 versus 8.0 respectively, P = 0.672). CONCLUSIONS: Based on the data presented here, we failed to find a relationship between a national vaccination program and both the nature and incidence of AA presenting to a busy urban hospital.

A new implantable tool for repeated assessment of supraventricular electrophysiology and atrial fibrillation susceptibility in freely moving rats.

The complex pathophysiology of atrial fibrillation (AF) is governed by multiple risk factors in ways that are still elusive. Basic electrophysiological properties, including atrial effective refractory period (AERP) and conduction velocity, are major factors determining the susceptibility of the atrial myocardium to AF. Although there is a great need for affordable animal models in this field of research, in vivo rodent studies are limited by technical challenges. Recently, we introduced an implantable system for long-term assessment of AF susceptibility in ambulatory rats. However, technical considerations did not allow us to perform concomitant supraventricular electrophysiology measurements. Here, we designed a novel quadripolar electrode specifically adapted for comprehensive atrial studies in ambulatory rats. Electrodes were fabricated from medical-grade silicone, four platinum-iridium poles, and stainless-steel fixating pins. Initial quality validation was performed ex vivo, followed by implantation in adult rats and repeated electrophysiological studies 1, 4, and 8 wk postimplantation. Capture threshold was stable. Baseline AERP values (38.1 ± 2.3 and 39.5 ± 2.0 using 70-ms and 120-ms S1-S1 cycle lengths, respectively) confirmed the expected absence of rate adaptation in the unanesthetized state and validated our prediction that markedly higher values reported under anesthesia are nonphysiological. Evaluation of AF substrate in parallel with electrophysiological parameters validated our recent finding of a gradual increase in AF susceptibility over time and demonstrated that this phenomenon is associated with an electrical remodeling process characterized by AERP shortening. Our findings indicate that the miniature quadripolar electrode is a potent new tool, which opens a window of opportunities for better utilization of rats in AF research.NEW & NOTEWORTHY Rodents are increasingly used in AF research. However, technical challenges restrict long-term supraventricular electrophysiology studies in these species. Here, we developed an implantable electrode adapted for such studies in the rat. Our findings indicate that this new tool is effective for long-term follow-up of critical parameters such as atrial refractoriness. Obtained data shed light on the normal electrophysiology and on the increased AF susceptibility that develops in rats with implanted atrial electrodes over time.

Awareness and usage of evidence-based learning strategies among health professions students and faculty.

Introduction: Learning is essential and life-long for faculty and students. Often students and teachers use ineffective learning strategies and are not aware of evidence-based strategies.Methods: A multicenter, international, cross-sectional, online survey-based assessment of awareness of evidence-based learning strategies among health professions students (n = 679) and faculty (n = 205).Results: Students endorsed many study habits which violate evidence-based principles, including studying whatever is due soonest (389/679, 57%), failing to return to course material once a course has ended (465/679, 68%), and re-reading underlined or highlighted notes (298.679, 44%). While the majority of faculty surveyed (125/157, 80%) reported recommending effective study strategies for their students, most students (558/679, 82%) said they did not study the way they do because of instruction from faculty. The majority of faculty (142/156, 91%) and students (347/661, 53%) believe students have different learning styles.Discussion: The results of this study demonstrate health professions students continue to use many ineffective study strategies, and both students and faculty hold misconceptions about evidence-based learning. While planning a curriculum, medical educators should focus on teaching students how to learn and use higher order thinking procedures in addition to teaching content.

Jerusalem's CoVID-19 Experience-The Effect of Ethnicity on Disease Prevalence and Adherence to Testing.

BACKGROUND: The management of the SARS-CoV-2 pandemic depends amongst other factors on disease prevalence in the general population. The gap between the true rate of infection and the detected rate of infection may vary, especially between sub-groups of the population. Identifying subpopulations with high rates of undetected infection can guide authorities to direct resource distribution in order to improve health equity. METHODS: A cross-sectional epidemiological survey was conducted between April and July 2021 in the Pediatric Emergency Department of the Shaare Zedek Medical Center, Jerusalem, Israel. We compared three categories: unconfirmed disease (UD), positive serology test result with no history of positive PCR; confirmed disease (CD), history of a positive PCR test result, regardless of serology test result; and no disease (ND), negative serology and no history of PCR. These categories were applied to local prevailing subpopulations: ultra-orthodox Jews (UO), National Religious Jews (NRJ), secular Jews (SJ), and Muslim Arabs (MA). RESULTS: Comparing the different subpopulations groups, MAs and UOs had the greatest rate of confirmed or unconfirmed disease. MA had the highest rate of UD and UO had the highest rate of CD. UD significantly correlated with ethnicity, with a low prevalence in NRJ and SJ. UD was also associated with larger family size and housing density defined as family size per number of rooms. CONCLUSION: This study highlights the effect of ethnicity on disease burden. These findings should serve to heighten awareness to disease burden in weaker populations and direct a suitable prevention program to each subpopulation's needs. Early awareness and possible intervention may lower morbidity and mortality.

The impact of osimertinib' line on clonal evolution in EGFRm NSCLC through NGS-based liquid biopsy and overcoming strategies for resistance.

BACKGROUND: Resistance mechanisms following 1st line therapy with osimertinib in EGFR + NSCLC have become focus of investigation. This retrospective study aims to deepen the understanding and clarify possible mechanisms of osimertinib 1st line resistance in comparison to the 2nd line by examining NGS results of 30 patients who developed resistance to osimertinib. Furthermore, we followed clinical outcomes of select patients who received combined therapy following EGFR resistance, a novel strategy not yet widely tested. METHODS: Liquid biopsy technique (Guardant360) was used to monitor tumor dynamics in patients who were treated with osimertinib as 1st-line therapy (Group A, N = 15) and patients who received osimertinib as 2nd-line therapy (Group B, N = 15). RESULTS: At the time of progression under osimertinib all but one patient preserved the primary EGFR mutation. While the C797S mutation was relatively common in the 2nd-line osimertinib setting (5/15), it did not develop in group A patients. TP53 was the most common detected mutation among all patients accounting for 11/15 in group A (73.33 %) and 10/15 in group B (66.67 %). In group A MET amplification was found in 3/15 patients (20 %) whereas MET mutation appeared in only one patient from group B. The outcomes of different treatment approaches post osimertinib resistance is reported including chemotherapy with/without osimertinib for maintaining control of brain metastases, drug combination such as osimertinib with crizotinib, chemo-immunotherapy and others. Overall survival in this cohort ranged from 12 to80 months. CONCLUSIONS: Mechanisms of resistance to osimertinib as 1st-line therapy differ from those which develop in the 2nd-line setting and commonly include MET amplification. C797S is not a main resistance mechanism in the 1st-line setting, whereas it is more common in the 2nd-line setting. Combined therapy was effective and well tolerated, making it an acceptable choice in patients for whom there is a reasonable rationale for such treatment, however this approach deserves further investigation.

Gender and lung cancer-SEER-based analysis.

BACKGROUND: Lung cancer remains a major cause of death worldwide. While in the past it was considered to primarily afflict males, in recent decades the number of female patients has risen, such that rates among females are similar to those among males. Nevertheless, it has been found previously (e.g., in cardiovascular disease) that when there is a sex-specific stereotype to a disease, it may remain entrenched in medical diagnostic processes, so as to cause belated diagnosis among the other sex. Gender-based differences in incidence and diagnosis are likely to exist with respect to lung cancer because of smoking habits and stereotypes, geographic and socioeconomic differences, and past epidemiologic differences between the sexes. Here we aim to characterize the effects of gender on lung cancer diagnosis and whether such effects have changed over time. METHODS: The SEER (Statistics, Epidemiology, and End Results) database was used to check for sex-based differences by tumor type and stage at diagnosis and to investigate whether these patterns have changed with time by comparing staging data in different age cohorts over time. Results were stratified by location and analyzed with data regarding possible confounders such as smoking and socioeconomic factors. RESULTS: We examined 458,132 cases of lung cancer from the years 2004-2012; 243,021 (53%) in males and 215,111 (47%) in females. Lung cancer rates were 73.8 (73.5-74.1) per 100k in males and 51.6 (51.4-51.8) per 100k in females. Of these, 400,800 had the stage listed, 214,479 (54%) in males, and 186,321 (46%) in females. Total lung cancer rates were higher in males than females at all disease stages. Male patients were more likely than female patients to be diagnosed at stage 3-4, consistent across lung cancer types, cancer registries, smoking, and socioeconomic backgrounds. The difference between the percentage of males versus females diagnosed in stages 3-4 correlated negatively with increased female ever-smokers and with squamous and small cell carcinoma and were not correlated with the rate of cancer in females, or the difference between male and female cancer rates. CONCLUSIONS: Our study showed that there is no belated diagnosis of lung cancer in females. Results appear to point to the fact that smoking females are more likely to be diagnosed at later stages, which is consistent with the current literature.

VDAC1 in the diseased myocardium and the effect of VDAC1-interacting compound on atrial fibrosis induced by hyperaldosteronism.

The voltage-dependent anion channel 1 (VDAC1) is a key player in mitochondrial function. VDAC1 serves as a gatekeeper mediating the fluxes of ions, nucleotides, and other metabolites across the outer mitochondrial membrane, as well as the release of apoptogenic proteins initiating apoptotic cell death. VBIT-4, a VDAC1 oligomerization inhibitor, was recently shown to prevent mitochondrial dysfunction and apoptosis, as validated in mouse models of lupus and type-2 diabetes. In the present study, we explored the expression of VDAC1 in the diseased myocardium of humans and rats. In addition, we evaluated the effect of VBIT-4 treatment on the atrial structural and electrical remodeling of rats exposed to excessive aldosterone levels. Immunohistochemical analysis of commercially available human cardiac tissues revealed marked overexpression of VDAC1 in post-myocardial infarction patients, as well as in patients with chronic ventricular dilatation\dysfunction. In agreement, rats exposed to myocardial infarction or to excessive aldosterone had a marked increase of VDAC1 in both ventricular and atrial tissues. Immunofluorescence staining indicated a punctuated appearance typical for mitochondrial-localized VDAC1. Finally, VBIT-4 treatment attenuated the atrial fibrotic load of rats exposed to excessive aldosterone without a notable effect on the susceptibility to atrial fibrillation episodes induced by burst pacing. Our results indicate that VDAC1 overexpression is associated with myocardial abnormalities in common pathological settings. Our data also indicate that inhibition of the VDAC1 can reduce excessive fibrosis in the atrial myocardium, a finding which may have important therapeutic implications. The exact mechanism\s of this beneficial effect need further studies.

An implantable system for long-term assessment of atrial fibrillation substrate in unanesthetized rats exposed to underlying pathological conditions.

Atrial fibrillation (AF) is a progressive arrhythmia with underlying mechanisms that are not fully elucidated, partially due to lack of reliable and affordable animal models. Here, we introduce a system for long-term assessment of AF susceptibility (substrate) in ambulatory rats implanted with miniature electrodes on the atrium. Rats were subjected to excessive aldosterone (Aldo) or solvent only (Sham). An additional group was exposed to myocardial infarction (MI). AF substrate was tested two- and four-weeks post implantation and was also compared with implanted rats early post-implantation (Base). Aldo and MI increased the AF substrate and atrial fibrosis. In the MI group only, AF duration was correlated with the level of atrial fibrosis and was inversely correlated with systolic function. Unexpectedly, Shams also developed progressive AF substrate relative to Base individuals. Further studies indicated that serum inflammatory markers (IL-6, TNF-alpha) were not elevated in the shams. In addition, we excluded anxiety\depression due to social-isolation as an AF promoting factor. Finally, enhanced biocompatibility of the atrial electrode did not inhibit the gradual development of AF substrate over a testing period of up to 8 weeks. Overall, we successfully validated the first system for long-term AF substrate testing in ambulatory rats.

Efficient high-throughput SARS-CoV-2 testing to detect asymptomatic carriers.

Recent reports suggest that 10 to 30% of severe acute respiratory syndrome coronavirus 2 (SARS- CoV-2) infected patients are asymptomatic and that viral shedding may occur before symptom onset. Therefore, there is an urgent need to increase diagnostic testing capabilities to prevent disease spread. We developed P-BEST, a method for Pooling-Based Efficient SARS-CoV-2 Testing, which identifies all positive subjects within a set of samples using a single round of testing. Each sample is assigned into multiple pools using a combinatorial pooling strategy based on compressed sensing. We pooled sets of 384 samples into 48 pools, providing both an eightfold increase in testing efficiency and an eightfold reduction in test costs, while identifying up to five positive carriers. We then used P-BEST to screen 1115 health care workers using 144 tests. P- BEST provides an efficient and easy-to-implement solution for increasing testing capacity that can be easily integrated into diagnostic laboratories.

GLASS: Global Lorlatinib for ALK(+) and ROS1(+) retrospective Study: real world data of 123 NSCLC patients.

Lorlatinib is a third-generation tyrosine-kinases inhibitor (TKI) targeting ALK/ROS1 fusions. The FDA has approved lorlatinib for TKI-pretreated ALK(+) NSCLC, while its approval for ROS1(+) is still pending. Here we present the largest real-world data of NSCLC patients harboring ALK/ROS1 rearrangements treated with lorlatinib. METHODS: 123 patients were enrolled retrospectively (data cut-off 1/1/2019). Lorlatinib was administered through an early access program for patients with no other available therapy. Outcome and response were defined by each investigator upon RECIST 1.1 criteria. RESULTS: 106 ALK(+) and 17 ROS1(+) patients recruited from 8 different countries. The ALK(+) cohort included 50 % males, 73 % never-smokers and 68 % with brain metastases. Extracranial (EC) and intracranial (IC) response rates (RR) were 60 % and 62 %, with disease control rates (DCR) of 91 % and 88 % respectively. Mean duration of therapy (DoT) was 23.9 ±â€¯1.6 months and median overall survival (mOS) was 89.1 ±â€¯19.6 months. ROS1 cohort enrolled 53 % males, 65 % never-smokers and 65 % had brain metastases. EC and IC RR were 62 % and 67 % with DCR of 92 % and 78 % respectively. Median DoT was 18.1 ±â€¯2.5 months and mOS of 90.3 ±â€¯24.4 months. OS and DoT in both cohorts were not significantly correlated with line of therapy nor other parameters. The most common adverse events of any grade were peripheral edema (48 %), hyperlipidemia (47 %), weight gain (25 %) and fatigue (30 %). CNS adverse events such as cognitive effect of grade 1-2 were reported in 18 % of patients. CONCLUSION: Lorlatinib shows outstanding EC/IC efficacy in ALK/ROS1(+) NSCLC. The observed mOS of 89 ±â€¯19 months in ALK(+) NSCLC supports previous reports, while mOS from of 90 ±â€¯24 months is unprecedented for ROS1(+) NSCLC.

Increased Incidence of Lung Cancer Among Patients With Superficial Transitional Cell Carcinoma: A Potential Risk Cohort for Lung Cancer Screening.

BACKGROUND: Smoking is a major risk factor for lung cancer (LC) and transitional cell carcinoma of the bladder (TCC). Current recommendations for LC screening do not include TCC as a risk factor for determining screening eligibility. In this study we aimed to evaluate whether TCC patients constitute a population who might benefit from LC screening. PATIENTS AND METHODS: The Surveillance, Epidemiology, and End Results 18 database was used to determine the incidence, standardized incidence ratio (SIR), and the average time to diagnosis of LC in patients with localized TCC of the bladder (American Joint Committee on Cancer, sixth edition, stages 0-1). RESULTS: On the basis of 91,606 patients with localized TCC, The SIR for LC in men was 1.89 (95% confidence interval [CI], 1.8-1.97), significantly different from the risk for all solid tumors. The SIR for LC in women was 2.43 (95% CI, 2.22-2.65), significantly higher than for men. The 5-year incidence of LC was 3.2%, and the 10-year incidence was 5.94%. The average time to diagnosis of LC was 3.4 years, with >80% of LC cases occurring within 5 years of TCC diagnosis. CONCLUSION: Patients with localized TCC have a higher incidence of LC than the general population. The risk is significantly increased among women compared with men. Considering this increased risk, patients with early stage TCC might stand to benefit from LC screening. Additional differences were noted between male and female TCC patients, which bear further study.

Rapid Atrial Pacing Promotes Atrial Fibrillation Substrate in Unanesthetized Instrumented Rats.

AIM: The self-perpetuating nature of atrial fibrillation (AF) has been a subject of intense research in large mammalian models exposed to rapid atrial pacing (RAP). Recently, rodents are increasingly used to gain insight into the pathophysiology of AF. However, little is known regarding the effects of RAP on the atria of rats and mice. Using an implantable device for electrophysiological studies in rodents, we examined on a daily basis, the effects of continuous RAP on the developed AF substrate of unanesthetized rats and mice. METHODS AND RESULTS: Aggressive burst pacing did not induce AF at baseline in the large majority of rodents, but repeatedly induced AF episodes in rats exposed to RAP for more than 2 days. A microarray study of left atrial tissue from rats exposed to RAP for 2 days vs. control pacing identified 304 differentially expressed genes. Enrichment analysis and comparison with a dataset of atrial tissue from AF patients revealed indications of increased carbohydrate metabolism and changes in pathways that are thought to play critical roles in human AF, including TGF-beta and IL-6 signaling. Among 19 commonly affected genes in comparison with human AF, downregulation of FOXP1 and upregulation of the KCNK2 gene encoding the Kir2.1 potassium channel were conspicuous findings, suggesting NFAT activation. Further results included reduced expression of MIR-26 and MIR-101, which is in line with NFAT activation. CONCLUSION: Our results demonstrate electrophysiological evidence for AF promoting effects of RAP in rats and several molecular similarities between the effects of RAP in large and small mammalian models.

Unanesthetized Rodents Demonstrate Insensitivity of QT Interval and Ventricular Refractory Period to Pacing Cycle Length.

Aim: The cardiac electrophysiology of mice and rats has been analyzed extensively, often in the context of pathological manipulations. However, the effects of beating rate on the basic electrical properties of the rodent heart remain unclear. Due to technical challenges, reported electrophysiological studies in rodents are mainly from ex vivo preparations or under deep anesthesia, conditions that might be quite far from the normal physiological state. The aim of the current study was to characterize the ventricular rate-adaptation properties of unanesthetized rats and mice. Methods: An implanted device was chronically implanted in rodents for atrial or ventricular pacing studies. Following recovery from surgery, QT interval was evaluated in rodents exposed to atrial pacing at various frequencies. In addition, the frequency dependence of ventricular refractoriness was tested by conventional ventricular programmed stimulation protocols. Results: Our findings indicate total absence of conventional rate-adaptation properties for both QT interval and ventricular refractoriness. Using monophasic action potential recordings in isolated mice hearts we could confirm the previously reported shortening of the action potential duration at fast pacing rates. However, we found that this mild shortening did not result in similar decrease of ventricular refractory period. Conclusion: Our findings indicate that unanesthetized rodents exhibit flat QT interval and ventricular refractory period rate-dependence. This data argue against empirical use of QT interval correction methods in rodent studies. Our new methodology allowing atrial and ventricular pacing of unanesthetized freely moving rodents may facilitate more appropriate utility of these important animal models in the context of cardiac electrophysiology studies.

Prominent differences in left ventricular performance and myocardial properties between right ventricular and left ventricular-based pacing modes in rats.

Biventricular pacing is an important modality to improve left ventricular (LV) synchronization and long-term function. However, the biological effects of this treatment are far from being elucidated and existing animal models are limited and demanding. Recently, we introduced an implanted device for double-site epicardial pacing in rats and echocardiographically demonstrated favorable effects of LV and biventricular (LV-based) pacing modes typically observed in humans. Here, this new animal model was further characterized. Electrodes were implanted either on the right atria (RA) and right ventricle (RV) or on the RV and LV. Following recovery, rats were either used for invasive hemodynamic measurements (pressure-volume analysis) or exposed to sustained RV vs. biventricular tachypacing for 3 days. RV pacing compromised, while LV-based pacing modes markedly enhanced cardiac performance. Changes in LV performance were associated with prominent compensatory changes in arterial resistance. Sustained RV tachypacing increased the electrocardiogram QTc interval by 7.9 ± 3.1 ms (n = 6, p < 0.05), dispersed refractoriness between the right and left pacing sites and induced important molecular changes mainly in the early-activated septal tissue. These effects were not observed during biventricular tachypacing (n = 6). Our results demonstrate that the rat is an attractive new model to study the biological consequences of LV dyssynchrony and resynchronization.