Citations

ABSTRACT General surgery is a dynamic and multifaceted field influenced by diverse factors, ranging from cultural norms to healthcare system structures and technological advancements. This review paper delves into a comparative exploration of the educational landscapes in Canada and India, unravelling the intricacies of training aspiring general surgeons. As two nations with distinct healthcare systems and educational frameworks, Canada and India offer unique perspectives on the journey from medical school to independent surgical practice. This article compares the residency application process, training structure, assessment methods, challenges faced during clinical training and the role of research in surgical programmes between the two nations. Through this comparative lens, we seek to provide valuable insights that may inform future developments in surgical education, fostering a global exchange of knowledge and practices to advance healthcare systems worldwide.

Objectives: During cochlear implant (CI) electrode placement, single low-frequency (e.g., 500 Hz) cochlear microphonics (CM) measurements are used to monitor hair-cell function and provide feedback to avert insertion trauma. However, it can be difficult to differentiate between trauma and the electrode’s progression through the cochlea when monitored with a single frequency. Multi-frequency CM measurements, while more complex to analyze, can provide more accurate feedback by measuring CM from various locations along the basilar membrane. Methods: A new algorithm was developed to analyze multi-frequency CM tracings by comparing amplitude and phase changes across different test frequencies. The new algorithm was evaluated as to its ability to identify drop-alarm instances with the multi-frequency approach, as compared to single-frequency 500 Hz tracings. Results: The algorithm presented in this manuscript uses the relationship between CM amplitude and phase changes across frequencies to provide real-time feedback during CI electrode placement. The results show that multi-frequency CM tracings raised an alarm only 0.5 times, as compared to 2.8 instances of alarm raised for the single-frequency 500 Hz CM measurements. Conclusions: Multi-frequency CM tracings can help reduce the number of alarms which may be false positives prompting unnecessary electrode manipulations, thereby minimizing the risk of insertion trauma.

Abstract Purpose: The three-arm, phase III KEYNOTE-361 study did not meet its dual primary endpoints of progression-free survival (PFS) or overall survival (OS) with first-line pembrolizumab plus chemotherapy versus chemotherapy in advanced urothelial carcinoma. This prespecified exploratory analysis assessed the association of tumor mutational burden (TMB) and PD-L1 combined positive score (CPS) with clinical outcomes. Patients and Methods: TMB and PD-L1 CPS were determined via whole-exome sequencing and PD-L1 IHC 22C3 pharmDx, respectively. The association was evaluated in each treatment arm using logistic regression [objective response rate (ORR)] and Cox proportional hazards regression models (PFS and OS); one-sided (pembrolizumab monotherapy; pembrolizumab plus chemotherapy) and two-sided (chemotherapy) nominal P values were calculated. Significance was prespecified at α = 0.05 without multiplicity adjustment. Efficacy was evaluated by prespecified cutoffs of 175 mutations/exome (TMB) and CPS 10 (PD-L1). Results: Of the 993 treated patients, 820 (82.6%) and 993 (100%) had evaluable TMB and CPS data, respectively. Continuous TMB was positively associated with ORR, PFS, and OS for pembrolizumab monotherapy (one-sided P < 0.001, P < 0.001, and P = 0.007, respectively); PFS and OS for pembrolizumab plus chemotherapy (one-sided P = 0.007 and P = 0.010, respectively); and OS for chemotherapy alone (two-sided P = 0.040). Continuous PD-L1 CPS showed evidence of anticipated association with ORR and PFS for pembrolizumab monotherapy. The subgroup with TMB ≥175 mutations/exome and PD-L1 CPS ≥10 had the highest PFS and OS improvements with pembrolizumab alone or with chemotherapy versus chemotherapy alone. Conclusions: These data suggest that TMB may be predictive of the response to pembrolizumab alone or with chemotherapy in advanced urothelial carcinoma.

Abstract Background Delirium, an acute brain dysfunction, is proposed to be highly prevalent in clinical care and shown to significantly increase the risk of mortality and dementia. Objectives To report on the global prevalence of clinically documented delirium and delirium-related clinical practices in wards caring for paediatric and adult patients in healthcare facilities. Design A prospective, cross-sectional, 39-question survey completed on World Delirium Awareness Day, 15 March 2023. Participants Clinicians or researchers with access to clinical data. Main Outcome and Measure The primary outcome was the prevalence of clinically documented delirium at 8:00 a.m. (4 h) and 8:00 p.m. (±4 h). Secondary outcomes included delirium-related care practices and barriers to use. Descriptive statistics were calculated and multilevel modelling was completed. Results 1664 wards submitted surveys from 44 countries, reporting on delirium assessments at 8:00 a.m. (n = 36 048) and 8:00 p.m. (n = 32 867); 61% reported use of validated delirium assessment tools. At 8:00 a.m., 18% (n = 2788/15 458) and at 8:00 p.m., 17.7% (n = 2454/13 860) were delirium positive. Top prevention measures were pain management (86.7%), mobilisation (81.4%) and adequate fluids (80.4%). Frequently reported pharmacologic interventions were benzodiazepines (52.7%) and haloperidol (46.2%). Top barriers included the shortage of staff (54.3%), lack of time to educate staff (48.6%) and missing knowledge about delirium (38%). Conclusion and Relevance In this study, approximately one out of five patients were reported as delirious. The reported high use of benzodiazepines needs further evaluation as it is not aligned with best-practice recommendations. Findings provide a benchmark for future quality improvement projects and research.

Abstract Protease activated receptor 2 (PAR2) is a G-protein coupled receptor expressed in meningeal neurons, fibroblasts and mast cells that may be targeted to treat migraine. MEDI0618, a fully humanized PAR2 monoclonal antibody, engineered to enhance FcRn-dependent recycling and currently in clinical development, was evaluated in human and rodent in vitro assays, in multiple murine in vivo migraine models and in a model of post-traumatic headache. MEDI0618 bound specifically and with high affinity to cells expressing human PAR2 (hPAR2) and prevented matriptase-induced increase in cytosolic calcium. Similarly, MEDI0618 prevented matriptase-induced calcium in primary fibroblasts and microvascular endothelial cells from human dura mater. MEDI0618 had no effect on hPAR1 receptors. Single-cell calcium imaging of acutely dissociated mouse trigeminal ganglion neurons confirmed expression and functionality of mouse PAR2. Studies in vivo used evoked cutaneous allodynia as a surrogate of headache-like pain and, in some experiments, rearing as a measure of non-evoked headache pain. MEDI0618 was administered subcutaneously to C57BL6/J female mice prior to induction of migraine-like pain with (i) systemic nitroglycerin or compound 48/80 (mast cell degranulator); or (ii) with supradural compound 48/80 or an inflammatory mediator (IM) cocktail. To assess possible efficacy against CGRP receptor (CGRP-R)-independent pain, MEDI0618 was also evaluated in the IM model in animals pretreated with systemic olcegepant (CGRP-R antagonist). Migraine-like pain was also induced by inhalational umbellulone, a TRPA1 agonist, in animals primed with restraint stress in the presence or absence of MEDI0618 as well as in a model of post-traumatic headache pain induced by a mild traumatic brain injury. MEDI0618 prevented cutaneous allodynia elicited by systemic nitroglycerin, compound 48/80 and from supradural compound 48/80 and IM. Systemic olcegepant completely blocked periorbital cutaneous allodynia induced by supradural CGRP but failed to reduce IM-induced cutaneous allodynia. In contrast, MEDI0618 fully prevented IM-induced cutaneous allodynia, regardless of pretreatment with olcegepant. Umbellulone elicited cutaneous allodynia only in restraint stress-primed animals, which was prevented by MEDI0618. MEDI0618 prevented the decrease in rearing behaviour elicited by compound 48/80. However, MEDI0618 did not prevent mild traumatic brain injury-related post-traumatic headache measures. These data indicate that MEDI0618 is a potent and selective inhibitor of PAR2 that is effective in human and rodent in vitro cell systems. Further, blockade of PAR2 with MEDI0618 was effective in all preclinical migraine models studied but not in a model of post-traumatic headache. MEDI0618 may represent a novel therapy for migraine prevention with activity against CGRP-dependent and independent attacks.

ABSTRACT Over the past two decades, there has been increasing interest in the diagnosis and management of schwannomas of the inner ear including hearing rehabilitation with cochlear implants. However, tumor nomenclature and classification within the literature have been variable and oftentimes cumbersome. The term “intralabyrinthine schwannoma” is in common use when describing these tumors but is a potential source of confusion given that people often use the term “labyrinth” or “labyrinthine” to refer to the vestibular component of the inner ear only (i.e., labyrinthectomy or the translabyrinthine approach). During the Ninth Quadrennial Conference on Vestibular Schwannoma and Other Cerebellopontine Angle Lesions in Bergen, Norway, in May 2023, a multidisciplinary group of conference participants met and discussed issues pertaining to current terminology and classifications to enhance clarity and to reflect recent advances in tumor management and hearing rehabilitation. Although a variety of terms have been previously used to describe inner ear schwannomas, consensus was achieved on the term “inner ear schwannoma (IES)” to describe eighth nerve schwannomas of the cochlea, vestibule, or semicircular canals. Subgroups under this term comprise intravestibular, intracochlear, or intravestibulocochlear inner ear schwannomas (low complexity tumors), inner ear schwannomas with transfundal extension into the internal auditory canal but without modiolar involvement (intermediate complexity tumors), and inner ear schwannomas with transfundal extension with modiolar involvement (high complexity tumors). The details of the recommendations for an updated and simplified tumor nomenclature centered around tumor control and hearing rehabilitation with cochlear implantation are presented.

Neurodegenerative disorders are major health concerns globally, especially in aging societies. The exploration of brain epigenomes, which consist of multiple forms of DNA methylation and covalent histone modifications, offers new and unanticipated perspective into the mechanisms of aging and neurodegenerative diseases. Initially, chromatin defects in the brain were thought to be static abnormalities from early development associated with rare genetic syndromes. However, it is now evident that mutations and the dysregulation of the epigenetic machinery extend across a broader spectrum, encompassing adult-onset neurodegenerative diseases. Hence, it is crucial to develop methodologies that can enhance epigenetic research. Several approaches have been created to investigate alterations in epigenetics on a spectrum of scales—ranging from low to high—with a particular focus on detecting DNA methylation and histone modifications. This article explores the burgeoning realm of neuroepigenetics, emphasizing its role in enhancing our mechanistic comprehension of neurodegenerative disorders and elucidating the predominant techniques employed for detecting modifications in the epigenome. Additionally, we ponder the potential influence of these advancements on shaping future therapeutic approaches.

ABSTRACTMetachromatic leukodystrophy (MLD) is a rare neurodegenerative lysosomal storage disease resulting from bi‐allelic pathogenic variants in the ARSA gene. MLD is distinguished clinically based on the age of onset into late‐infantile, juvenile, and adult. The late‐infantile type is the most severe phenotype presenting with hypotonia, weakness, gait abnormalities, which progresses to mental and physical decline leading to early death. MLD is considered to be pan‐ethnic and no founder variants have previously been described in the Ashkenazi Jewish population. We identified three unrelated individuals of Ashkenazi Jewish descent with homozygosity or compound heterozygosity for the c.178C>T (p.Arg60Trp) variant in the ARSA gene, with a phenotype consistent with late‐infantile MLD. The carrier frequency was calculated among 93,293 individuals of Ashkenazi Jewish descent through the Dor Yeshorim screening program and found to have a carrier frequency on 1 in 1554 or 0.06%, which may be representative of a founder variant. Molecular protein modeling showed that the variant affects regional folding. Late‐infantile MLD should be considered when the c.178C>T (p.Arg60Trp) variant in the ARSA gene is present in either the homozygous or the compound heterozygous states.

Abstract Aims In the VICTORIA (Vericiguat Global Study in Subjects with Heart Failure with Reduced Ejection Fraction) trial, the soluble guanylate cyclase stimulator vericiguat reduced the risk of hospitalization for heart failure (HHF) or cardiovascular death in patients with heart failure (HF) and reduced ejection fraction (HFrEF) with recent worsening HF. The effect of vericiguat in patients with HFrEF without recent worsening HF remains unknown. The VICTOR (Vericiguat Global Study in Participants with Chronic Heart Failure) trial was designed to assess the efficacy and safety of vericiguat in patients with ejection fraction ≤40% without recent worsening HF on a background of current foundational HFrEF therapy. Methods The primary endpoint for VICTOR is time to first event for the composite of HHF or cardiovascular death. The trial will also assess the effect of vericiguat on time to cardiovascular death, time to HHF, total HHF, and all-cause death. As an event-driven trial, at least 1080 primary events are expected, but follow-up will continue until the targeted number of at least 590 cardiovascular deaths has been reached. Approximately 6000 participants will be randomized to vericiguat or placebo. Conclusion VICTOR is the first large event-driven HFrEF trial performed in the contemporary era of quadruple foundational guideline-directed medical therapy, in a compensated ambulatory HF population. VICTOR will add important information to the evidence of the effects of vericiguat across the spectrum of patients with HFrEF.