Task-Dependent Inhomogeneous Muscle Activities within the Bi-Articular Human Rectus Femoris Muscle

The motor nerve of the bi-articular rectus femoris muscle is generally split from the femoral nerve trunk into two sub-branches just before it reaches the distal and proximal regions of the muscle. In this study, we examined whether the regional difference in muscle activities exists within the human rectus femoris muscle during maximal voluntary isometric contractions of knee extension and hip flexion. Surface electromyographic signals were recorded from the distal, middle, and proximal regions. In addition, twitch responses were evoked by stimulating the femoral nerve with supramaximal intensity. The root mean square value of electromyographic amplitude during each voluntary task was normalized to the maximal compound muscle action potential amplitude (M-wave) for each region. The electromyographic amplitudes were significantly smaller during hip flexion than during knee extension task for all regions. There was no significant difference in the normalized electromyographic amplitude during knee extension among regions within the rectus femoris muscle, whereas those were significantly smaller in the distal than in the middle and proximal regions during hip flexion task. These results indicate that the bi-articular rectus femoris muscle is differentially controlled along the longitudinal direction and that in particular the distal region of the muscle cannot be fully activated during hip flexion

Somatic mosaicism and common genetic variation contribute to the risk of very-early-onset inflammatory bowel disease

Abstract: Very-early-onset inflammatory bowel disease (VEO-IBD) is a heterogeneous phenotype associated with a spectrum of rare Mendelian disorders. Here, we perform whole-exome-sequencing and genome-wide genotyping in 145 patients (median age-at-diagnosis of 3.5 years), in whom no Mendelian disorders were clinically suspected. In five patients we detect a primary immunodeficiency or enteropathy, with clinical consequences (XIAP, CYBA, SH2D1A, PCSK1). We also present a case study of a VEO-IBD patient with a mosaic de novo, pathogenic allele in CYBB. The mutation is present in ~70% of phagocytes and sufficient to result in defective bacterial handling but not life-threatening infections. Finally, we show that VEO-IBD patients have, on average, higher IBD polygenic risk scores than population controls (99 patients and 18,780 controls; P < 4 × 10−10), and replicate this finding in an independent cohort of VEO-IBD cases and controls (117 patients and 2,603 controls; P < 5 × 10−10). This discovery indicates that a polygenic component operates in VEO-IBD pathogenesis

SARS-CoV-2 vaccination in inflammatory bowel disease patients is not associated with flares: a retrospective single-centre Swiss study.

INTRODUCTION Vaccination hesitancy is an important barrier to vaccination among IBD patients. The development of adverse events is the main concern reported. The purpose of this monocentric study was to assess SARS-CoV-2 vaccination safety in IBD patients by evaluating the postvaccination flare risk and incidence of overall adverse events. METHODS Surveys were handed out on three consecutive months to each patient presenting at the Crohn-Colitis Centre, where they documented their vaccination status and any side effects experienced after vaccination.Dates of flares occurring in 2021 were recorded from their electronic medical records. Baseline and IBD characteristics and flare incidence were compared between the vaccinated and unvaccinated patients, and among the vaccinated population before and after their vaccination doses. The characteristics of patients who developed side effects and of those who did not were compared. RESULTS We enrolled 396 IBD patients, of whom 91% were vaccinated. The proportion of patients who experienced flares was statistically not different between the vaccinated and the unvaccinated population (1.8 vs 2.6 flares per 100 person-months (p = 0.28)). Among vaccinated patients, there was no difference across the prevaccination, 1 month post any vaccination, and more than 1 month after any vaccination periods, and between the Spikevax and Cominarty subgroups. Overall, 46% of patients reported vaccination side effects, mostly mild flu-like symptoms. CONCLUSION SARS-CoV-2 vaccination with mRNA vaccines seems safe, with mostly mild side effects. The IBD flare risk is not increased in the month following any vaccination