Evaluating the Effects of SARS-CoV-2 Spike Mutation D614G on Transmissibility and Pathogenicity.

Global dispersal and increasing frequency of the SARS-CoV-2 spike protein variant D614G are suggestive of a selective advantage but may also be due to a random founder effect. We investigate the hypothesis for positive selection of spike D614G in the United Kingdom using more than 25,000 whole genome SARS-CoV-2 sequences. Despite the availability of a large dataset, well represented by both spike 614 variants, not all approaches showed a conclusive signal of positive selection. Population genetic analysis indicates that 614G increases in frequency relative to 614D in a manner consistent with a selective advantage. We do not find any indication that patients infected with the spike 614G variant have higher COVID-19 mortality or clinical severity, but 614G is associated with higher viral load and younger age of patients. Significant differences in growth and size of 614G phylogenetic clusters indicate a need for continued study of this variant.

Circulating SARS-CoV-2 spike N439K variants maintain fitness while evading antibody-mediated immunity.

SARS-CoV-2 can mutate and evade immunity, with consequences for efficacy of emerging vaccines and antibody therapeutics. Here, we demonstrate that the immunodominant SARS-CoV-2 spike (S) receptor binding motif (RBM) is a highly variable region of S and provide epidemiological, clinical, and molecular characterization of a prevalent, sentinel RBM mutation, N439K. We demonstrate N439K S protein has enhanced binding affinity to the hACE2 receptor, and N439K viruses have similar in vitro replication fitness and cause infections with similar clinical outcomes as compared to wild type. We show the N439K mutation confers resistance against several neutralizing monoclonal antibodies, including one authorized for emergency use by the US Food and Drug Administration (FDA), and reduces the activity of some polyclonal sera from persons recovered from infection. Immune evasion mutations that maintain virulence and fitness such as N439K can emerge within SARS-CoV-2 S, highlighting the need for ongoing molecular surveillance to guide development and usage of vaccines and therapeutics.

KRAS and TP53 co-mutation predicts benefit of immune checkpoint blockade in lung adenocarcinoma.

BACKGROUND: Predictive biomarkers in use for immunotherapy in advanced non-small cell lung cancer are of limited sensitivity and specificity. We analysed the potential of activating KRAS and pathogenic TP53 mutations to provide additional predictive information. METHODS: The study cohort included 713 consecutive immunotherapy patients with advanced lung adenocarcinomas, negative for actionable genetic alterations. Additionally, two previously published immunotherapy and two surgical patient cohorts were analyzed. Therapy benefit was stratified by KRAS and TP53 mutations. Molecular characteristics underlying KRASmut/TP53mut tumours were revealed by the analysis of TCGA data. RESULTS: An interaction between KRAS and TP53 mutations was observed in univariate and multivariate analyses of overall survival (Hazard ratio [HR] = 0.56, p = 0.0044 and HR = 0.53, p = 0.0021) resulting in a stronger benefit for KRASmut/TP53mut tumours (HR = 0.71, CI 0.55-0.92). This observation was confirmed in immunotherapy cohorts but not observed in surgical cohorts. Tumour mutational burden, proliferation, and PD-L1 mRNA were significantly higher in TP53-mutated tumours, regardless of KRAS status. Genome-wide expression analysis revealed 64 genes, including CX3CL1 (fractalkine), as specific transcriptomic characteristic of KRASmut/TP53mut tumours. CONCLUSIONS: KRAS/TP53 co-mutation predicts ICI benefit in univariate and multivariate survival analyses and is associated with unique molecular tumour features. Mutation testing of the two genes can be easily implemented using small NGS panels.

VISUAL OUTCOMES AFTER INTERNAL LIMITING MEMBRANE PEELING VERSUS FLAP IN THE CLOSURE OF FULL-THICKNESS MACULAR HOLES.

PURPOSE: To examine postoperative outcomes of internal limiting membrane peeling (ILMP) versus flap (ILMF) in the closure of full-thickness macular holes. METHODS: Retrospective chart review of patients who underwent pars plana vitrectomy and gas tamponade with ILMP or ILMF to close full-thickness macular hole at the Atrium Health Wake Forest Baptist from January 2012 to October 2022 with at least 3 months follow-up. Main outcome measures were type 1 primary full-thickness macular hole closure and postoperative best-corrected visual acuity in mean logMAR. RESULTS: One hundred thirty and 30 eyes underwent ILMP and ILMF, respectively. There were no significant differences in baseline characteristics between the groups. Ninety-six percent of ILMP eyes and 90% of ILMF eyes achieved primary hole closure ( P = 0.29). Among all eyes with primary hole closure, best-corrected visual acuity at 1 year was not different between the groups, but when stratified by lens status, it was superior in the ILMP versus ILMF group in pseudophakic eyes: the estimated least-squares mean best-corrected visual acuity (Snellen equivalent) (95% confidence interval) was 0.42 (20/50) (0.34, 0.49) in the ILMP group and 0.71 (20/100) (0.50, 0.92) in the ILMF group. CONCLUSION: Internal limiting membrane peeling and ILMF techniques yielded similarly high full-thickness macular hole closure rates. In pseudophakic eyes with primary hole closure, ILMF eyes had worse best-corrected visual acuity at 1 year.

Real-world data for precision cancer medicine-A European perspective.

Leveraging real-world data (RWD) for drug access is necessary to overcome a key challenge of modern precision oncology: tackling numerous low-prevalence oncogenic mutations across cancers. Withholding a potentially active medication in patients with rare mutations for the sake of control chemotherapy or "best" supportive care is neither practicable nor ethically justifiable anymore, particularly as RWD could meanwhile be used instead, according to scientific principles outlined by the US Food and Drug Administration, European Medicines Agency and other stakeholders. However, practical implementation varies, with occasionally opposite recommendations based on the same evidence in different countries. In the face of growing need for precision drugs, more transparency of evaluation, a priori availability of guidance for the academia and industry, as well as a harmonized framework for health technology assessment across the European Union (EU) are imperative. These could in turn trigger infrastructural changes in national and pan-European registries, cancer management guidelines (e.g., frequency of routine radiologic restaging, inclusion of patient-reported outcomes), and the health data space, to ensure conformity with declared standards and facilitate extraction of RWD sets (including patient-level data) suitable for approval and pricing with minimal effort. For an EU-wide unification of precision cancer medicine, collective negotiation of drug supply contracts and funding solidarity would additionally be required to handle the financial burden. According to experience from pivotal European programs, off-label use could potentially also be harmonized across EU-states to accelerate availability of novel drugs, streamline collection of valuable RWD, and mitigate related costs through wider partnerships with pharmaceutical companies.

Application of a translational profiling approach for the comparative analysis of CNS cell types.

Comparative analysis can provide important insights into complex biological systems. As demonstrated in the accompanying paper, translating ribosome affinity purification (TRAP) permits comprehensive studies of translated mRNAs in genetically defined cell populations after physiological perturbations. To establish the generality of this approach, we present translational profiles for 24 CNS cell populations and identify known cell-specific and enriched transcripts for each population. We report thousands of cell-specific mRNAs that were not detected in whole-tissue microarray studies and provide examples that demonstrate the benefits deriving from comparative analysis. To provide a foundation for further biological and in silico studies, we provide a resource of 16 transgenic mouse lines, their corresponding anatomic characterization, and translational profiles for cell types from a variety of central nervous system structures. This resource will enable a wide spectrum of molecular and mechanistic studies of both well-known and previously uncharacterized neural cell populations.

Consent Practices for Assisted Vaginal Births (AVB) at Two Tertiary Care Hospitals: A Retrospective Review of Physician Documentation.

OBJECTIVE: To determine whether assisted vaginal birth (AVB) consent documentation, a surrogate for in vivo consent, aligns with Canadian practice guidelines at 2 Canadian tertiary-level obstetric centres. METHODS: This was a retrospective review of AVBs (vacuum and forceps) from July 2019 to December 2019 at 2 tertiary-level hospitals with template-based (Site 1) or dictation-based (Site 2) documentation. We extracted, from obstetric and neonatal charts, AVB type, physician and documenter types (resident/fellow/family doctor/generalist obstetrics and gynecology [OBGYN]/maternal-fetal medicine), and consent elements (present/absent) based on a predetermined checklist. Data were summarized and comparisons were made using chi-square test, Fisher exact test, and logistic regression, where appropriate. RESULTS: We identified 551 AVBs (156 forceps, 395 vacuum) with most documentation completed by generalist OBGYNs or residents (333/551, 60.5%). Most vacuum-assisted deliveries documented no specific maternal (366/395, 92.7%) or neonatal (364/395, 92.2%) risks, and 107/156 (68.6%) and 106/156 (67.9%) forceps-assisted deliveries lacked specific documentation of maternal and neonatal risk, respectively. At Site 2, postpartum hemorrhage risk at vacuum-assisted deliveries was more commonly documented (6/90 [6.7%] vs. 2/395 [0.7%], P = 0.002) as was at least 1 neonatal risk and risk of obstetrical anal sphincter injury at forceps-assisted deliveries (50/133 [37.6%] vs. 0/23 [0%], P < 0.001) and (43/133 [32.3%] vs. 0/23 [0%], P = 0.001), respectively. CONCLUSIONS: Opportunity to improve AVB consent documentation exists, warranting quality improvement initiatives.

A clinical and molecular epidemiological survey of hepatitis C in Blantyre, Malawi, suggests a historic mechanism of transmission.

Hepatitis C virus (HCV) is a leading cause of liver disease worldwide. There are no previous representative community HCV prevalence studies from Southern Africa, and limited genotypic data. Epidemiological data are required to inform an effective public health response. We conducted a household census-based random sampling serological survey, and a prospective hospital-based study of patients with cirrhosis and hepatocellular carcinoma (HCC) in Blantyre, Malawi. We tested participants with an HCV antigen/antibody ELISA (Monolisa, Bio-Rad), confirmed with PCR (GeneXpert, Cepheid) and used line immunoassay (Inno-LIA, Fujiribio) for RNA-negative participants. We did target-enrichment whole-genome HCV sequencing (NextSeq, Illumina). Among 96,386 censused individuals, we randomly selected 1661 people aged ≥16 years. Population-standardized HCV RNA prevalence was 0.2% (95% CI 0.1-0.5). Among 236 patients with cirrhosis and HCC, HCV RNA prevalence was 1.9% and 5.0%, respectively. Mapping showed that HCV RNA+ patients were from peri-urban areas surrounding Blantyre. Community and hospital HCV RNA+ participants were older than comparator HCV RNA-negative populations (median 53 vs 30 years for community, p = 0.01 and 68 vs 40 years for cirrhosis/HCC, p < 0.001). Endemic HCV genotypes (n = 10) were 4v (50%), 4r (30%) and 4w (10%). In this first census-based community serological study in Southern Africa, HCV was uncommon in the general population, was centred on peri-urban regions and was attributable for <5% of liver disease. HCV infection was observed only among older people, suggesting a historic mechanism of transmission. Genotype 4r, which has been associated with treatment failure with ledipasvir and daclatasvir, is endemic.

Seoul Virus Associated with Pet Rats, Scotland, UK, 2019.

We describe a case of hemorrhagic fever with renal syndrome caused by Seoul virus in a woman in Scotland, UK. Whole-genome sequencing showed the virus belonged to a lineage characterized by recent international expansion, probably driven by trade in pet rats.

Non-epidemic HCV genotypes in low- and middle-income countries and the risk of resistance to current direct-acting antiviral regimens.

The hepatitis C virus (HCV) is an extremely diverse virus, subtypes of which are distributed variably around the world. Viral genotypes may be divided into epidemic subtypes; those that have become prevalent globally, and endemic subtypes that have a more limited distribution, mainly in Africa and Asia. The high variability of endemic strains reflects evolutionary origins in the locations where they are found. This increased genetic diversity raises the possibility of resistance to pan-genotypic direct-acting antiviral regimens. While many endemic subtypes respond well to direct-acting antiviral therapies, others, for example genotypes 1l, 3b and 4r, do not respond as well as predicted. Many genotypes that are rare in high-income countries but common in other parts of the world have not yet been fully assessed in clinical trials. Further sequencing and clinical studies in sub-Saharan Africa and Asia are indicated to monitor response to treatment and to facilitate the World Health Organization's 2030 elimination strategy.

Society for Cardiovascular Magnetic Resonance 2019 Case of the Week series.

The Society for Cardiovascular Magnetic Resonance (SCMR) is an international society focused on the research, education, and clinical application of cardiovascular magnetic resonance (CMR). The SCMR web site ( https://www.scmr.org ) hosts a case series designed to present case reports demonstrating the unique attributes of CMR in the diagnosis or management of cardiovascular disease. Each clinical presentation is followed by a brief discussion of the disease and unique role of CMR in disease diagnosis or management guidance. By nature, some of these are somewhat esoteric, but all are instructive. In this publication, we provide a digital archive of the 2019 Case of the Week series as a means of further enhancing the education of those interested in CMR and as a means of more readily identifying these cases using a PubMed or similar search engine.

Cytoreductive Thoracic Surgery Combined with Hyperthermic Chemoperfusion for Pleural Malignancies: A Single-Center Experience.

BACKGROUND: Lung-sparing cytoreductive surgery by extended pleurectomy and decortication (EPD) in combination with hyperthermic intrathoracic chemoperfusion (HITOC) forms a promising treatment strategy for malignant pleural mesothelioma and recurrent pleural thymic malignancies. OBJECTIVES: The objective of this study was to scrutinize the surgical procedure and perioperative patient management with emphasis on perioperative morbidity and local tumor control. METHODS: In 2014, a standardized EPD and HITOC procedure was implemented at the Thoraxklinik Heidelberg. This retrospective analysis included clinical data of consecutive patients with pleural mesothelioma and pleural metastasized malignancies treated by EPD and HITOC. The surgical procedure, perioperative management, lung function data, and progression-free survival (PFS) were analyzed. RESULTS: In the time range between April 2, 2014 and July 2018, 76 patients with pleural malignancies have been treated with EPD and HITOC, and were analyzed retrospectively. It included 61 patients with pleural mesothelioma and 15 patients with pleural metastases of thymic malignancies (12), non-small cell lung cancer (1), colorectal carcinoma (1), and sarcoma (1). Perioperative morbidity following EPD and HITOC treatments represented 23.7% of overall malignancies, while 30- and 90-day mortality were 0 and 1.3%, respectively. Median PFS lasted 18.4 months for mesothelioma and 72.2 months for thymic malignancies. CONCLUSION: Combining EPD with HITOC can be performed in patients with either pleural mesothelioma or pleural metastases resulting in low perioperative morbidity and mortality as well as remarkable local tumor control.

Clinical Conundrum: A 39-Year-Old With Chronic Retained Products of Conception and Concurrent Uterine Arteriovenous Malformation.

A 39-year-old woman presented with bleeding 4 months after a surgical termination of pregnancy. Persistent beta-human chorionic gonadotropin levels were suggestive of retained products of conception (RPOC). However, multimodal imaging revealed a concurrent uterine arteriovenous malformation (AVM). Although most stable AVMs can be managed conservatively, the need for surgical management of chronic RPOC and consequential hemorrhage risk complicates this approach. Patient-determined management prioritized blood conservation while minimizing risks to fertility. This case is discussed with respect to the rare concurrent existence of RPOC and AVM. Little is known regarding the optimal tandem therapeutic approach. As depicted, successful treatment requires careful diagnostic workup and a multidisciplinary approach.

Validating an Obstetrics and Gynaecology Longitudinal Integrated Clerkship Curriculum at the University of Toronto: A Four-Year Review.

The University of Toronto launched a longitudinal integrated clerkship (LIC) pilot project in 2014. Our aim was to evaluate LIC student outcomes in obstetrics and gynaecology compared with those of traditional block students. LIC and block students underwent identical evaluations, including written and oral exams, as well as clinical assessments from the ward. LIC student scores in each domain were compared with those of the traditional block students over 4 years. There were no differences in overall pass/fail status between LIC and block students. Thus, our LIC design could be appropriately modeled at other teaching institutions contemplating introducing an LIC stream.

Prevalence of Food Insecurity Among Pregnant Women: A Canadian Study in a Large Urban Setting.

OBJECTIVE: Nutritional and financial needs increase during pregnancy, making pregnant women particularly vulnerable to food insecurity. Our objective was to document the prevalence of food insecurity among pregnant women receiving prenatal care in an urban centre in Canada and to identify factors associated with food insecurity. METHODS: This cross-sectional study recruited pregnant women receiving prenatal care at one of two Toronto hospitals: Site 1 and Site 2 (serving a more disadvantaged population) between October 1, 2018 and October 1, 2019. Demographic information was collected, and the U.S. Household Food Security Survey Module was used to assess food security. Comparisons were made using χ2 tests, two-tailed t tests, or Mann-Whitney tests for categorical and continuous variables, as appropriate. Binary logistic regression and multivariate analyses were performed to assess associations with food insecurity and differences between hospitals sites. RESULTS: We recruited 626 participants (316 at Site 1 and 310 at Site 2). Prevalence of food insecurity was 12.8% among all participants with Site 2 having nearly 5 times the prevalence of Site 1 (66/310 [21.3%] vs. 14/316 [4.4%]; P = 0.001). Several factors were associated with food insecurity, with non-White ethnicity (OR 2.04; 95% CI 0.98-4.25, P = 0.055] and lower household income (OR 37.53; 95% CI 14.04-100, P < 0.001 when less than CAD $23 000/y) being the most robust. CONCLUSION: This Canadian study documented the prevalence of and factors associated with food insecurity in pregnancy. Targeted interventions to help low-income women and programs geared towards non-White women may be beneficial in addressing food insecurity among pregnant women.

A case of cancer-associated retinopathy with chorioretinitis and optic neuritis associated with occult small cell lung cancer.

BACKGROUND: Cancer-associated retinopathy (CAR) is associated with various malignancies, including small cell lung cancer (SCLC). It is difficult to recognize, but prompt diagnosis is crucial for the patient, as retinopathy may be a herald sign that precedes systemic manifestations by months, thus allowing early treatment of the underlying malignancy. CASE PRESENTATION: We present a rare case of CAR with chorioretinitis and optic neuritis in a patient with occult SCLC. The patient presented with rapidly progressive peripheral field loss and photopsias with "prism-like" visual disturbances. Her symptoms stabilized with intravenous methylprednisolone, and her cancer was treated with carboplatin, etoposide and radiotherapy. CONCLUSIONS: This is the first reported case of SCLC-associated CAR to present with chorioretinitis. CAR can be a herald feature of SCLC, and early recognition of the disease should prompt a systemic evaluation for an occult malignancy, which may be critical for patient survival. Further understanding of CAR pathogenesis may offer potential avenues for treatment.

The State of Needlestick Training for Undergraduate Medical Students at Canadian Universities.

Canadian undergraduate medical students sustain needlestick injuries, which have adverse implications, including blood-borne illnesses and personal anxiety. This study sought to determine students' needle handling efficacy and to examine the prevalence of formal training around needlestick safety and reporting procedures both nationally and, specifically, within the University of Toronto in Toronto, Ontario (U of T). A seven-question survey electronic survey was distributed to 116 undergraduate medical education (UME) leaders practising in high-risk rotations at 13 Canadian universities. Additionally, an eight-question survey was delivered electronically to 428 residents, fellows, and faculty in the Department of Obstetrics and Gynaecology at the U of T. A total of 34% of UME leaders and 36% from the U of T responded. Of UME respondents, 53% reported that their institution lacks needlestick training, and 35% were unsure whether their institution provides reporting instruction. At the U of T, 53% were "concerned" or "very concerned" that students pose a risk to themselves, and 27% "disagreed" or "strongly disagreed" that students handle instruments correctly. Our findings suggest that needlestick safety training for medical students across Canadian universities is insufficient. It is concerning that students are frequently exposed to patients in high-risk and surgically intensive rotations, despite their inexperience with needles. Furthermore, non-reporting among students may prevent them from receiving early prophylaxis or treatment. There is a need for the national implementation of a standardized and formalized needlestick safety curriculum for medical students before and during clerkship.

Bridging the Gap: Incorporating Simulation into Obstetrics and Gynaecology Undergraduate Medical Education.

INTRODUCTION: Currently, simulation training is not part of the clinical clerkship rotation in obstetrics and gynaecology (OB/GYN) at the University of Toronto. Instead, students are taught formally through lectures and informally on the ward or in the operating room. This study aimed to incorporate simulation using a high fidelity postpartum hemorrhage (PPH) workshop into the teaching curriculum, with the goal of improving both medical knowledge of PPH and nontechnical skills (NTS). METHOD: A novel teaching session was introduced for the third-year clerks on their OB/GYN rotation. Students (n = 88) were invited to participate in the research component to evaluate the effectiveness of this session. Students' (n = 83) baseline knowledge of PPH and teamwork attitudes were measured using a multiple-choice questionnaire (MCQ) and the TeamSTEPPS Questionnaire. Students participated in small-group learning about PPH and NTS, followed by a high-fidelity PPH simulation using a Laerdal SimMom Mannequin in a mock operating room. Students were debriefed, followed by a different MCQ and the TeamSTEPPS Questionnaire. RESULTS: Statistically significant improvements in students' comprehension (MCQ scores 63.9% vs. 76.5%, P < 0.05) and NTS (4.35/5 vs. 4.51/5, P < 0.05) were noted after simulation. The majority (92%) of students agreed that this method of learning was more enjoyable than traditional methods. CONCLUSIONS: Simulation in undergraduate education offers an exciting alternative to deliver information that is traditionally taught with didactic sessions while incorporating essential NTS. The authors hope that this study will encourage discussion of current simulation practices across Canada and standardized simulation techniques in OB/GYN.

A Novel Approach to Simulation-Based Perineal Repair in Undergraduate Medical Education.

INTRODUCTION: There is no formalized hands-on teaching of suturing skills for clerkship students during their dedicated obstetrics and gynaecology (OB/GYN) teaching sessions at the University of Toronto. Nevertheless, the students are exposed to suturing during gynaecologic surgery, Caesarean sections, and perineal repairs. As a result, a formal pilot workshop on knot-tying and perineal laceration repair was developed for incorporation into the third-year clerkship curriculum with the goals of increasing students' knowledge and technical skills. METHODS: Participants consisted of students enrolled in their OB/GYN clerkship rotation at St. Michael's Hospital at the University of Toronto from December 2016 to August 2017. Prior to the workshop, students' (n = 82) baseline knowledge of perineal lacerations was assessed with a pre-test quiz and their knot-tying speeds (two hand-ties and two instrument ties) were recorded. Students were then taught perineal anatomy, laceration types and repair techniques, suturing, and knot-tying. Under direct supervision, students practiced the technical skills for 45 minutes. Knowledge and knot-tying speeds were then reassessed following the educational session. RESULTS: There was a statistically significant improvement in both knowledge (51% to 71%; P < 0.05) and technical skills (258.8 seconds to 197.4 seconds; P < 0.05) after the workshop. Importantly, 94% of students "agreed" or "strongly agreed" that this method of learning was more enjoyable than traditional methods. CONCLUSIONS: This pilot project demonstrates that a formal hands-on workshop improves medical knowledge, technical skills, and student satisfaction. This has the potential for students to have increased opportunities at the bedside, with higher patient acceptance and safety.