The NAD+-Dependent SIRT1 Deacetylase Translates a Metabolic Switch into Regulatory Epigenetics in Skeletal Muscle Stem Cells

SummaryStem cells undergo a shift in metabolic substrate utilization during specification and/or differentiation, a process that has been termed metabolic reprogramming. Here, we report that during the transition from quiescence to proliferation, skeletal muscle stem cells experience a metabolic switch from fatty acid oxidation to glycolysis. This reprogramming of cellular metabolism decreases intracellular NAD+ levels and the activity of the histone deacetylase SIRT1, leading to elevated H4K16 acetylation and activation of muscle gene transcription. Selective genetic ablation of the SIRT1 deacetylase domain in skeletal muscle results in increased H4K16 acetylation and deregulated activation of the myogenic program in SCs. Moreover, mice with muscle-specific inactivation of the SIRT1 deacetylase domain display reduced myofiber size, impaired muscle regeneration, and derepression of muscle developmental genes. Overall, these findings reveal how metabolic cues can be mechanistically translated into epigenetic modifications that regulate skeletal muscle stem cell biology

Bilious emesis as presenting symptom of congenital diaphragmatic hernia in an 8-month-old

Although congenital diaphragmatic hernia (CDH) primarily presents in either the prenatal or neonatal period, late presentation has a reported incidence of 2.5–25%. This case report describes an 8-month-old-male who presented to the emergency department with dehydration and a 24-h history of bilious emesis. Work-up led to the diagnosis of a left-sided Bochdalek CDH. He subsequently underwent laparoscopic diaphragmatic hernia repair with reduction of near-total length of incarcerated bowel. The patient had an uneventful recovery. Babies born with CDH are typically unstable at birth, and even with repair, the mortality rate remains high. However, in the case of delayed CDH diagnosis where there are no perinatal issues, surgical repair has very high success rates, provided that there are no complications regarding the delay. If there is not a high index of suspicion based on the patient's history and exam, delayed diagnosis and intervention with late CDH presentations can lead to complications which could otherwise be minimized. The purpose of this case report is to raise awareness and contribute to the growing knowledge about delayed CDH presentation among physicians and surgeons to facilitate early diagnosis and care of a morbid yet manageable condition

Monitoring Water Turbidity in a Temperate Floodplain Using UAV: Potential and Challenges

The Lake Saint-Pierre (LSP) is a wide (≈300 km2) and shallow (≈3 m) lake created through a widening of the St. Lawrence River. Each spring, freshet makes it the largest floodplain in the province of Quebec. Agricultural practices in the littoral increase the water turbidity, which deteriorate the habitat’s quality of many fish species. However, measuring spatio-temporal turbidity patterns in the LSP floodplain remain difficult because turbidity is highly variable in space and time. This study aims to evaluate the potential to use an Unmanned Aerial Vehicle (UAV) to measure the water turbidity in the LSP’s floodplain. The results show that the UAV can efficiently measure the variation of turbidity in the LSP with a RMSE of 28.22 FNU. We also compared the turbidity retrieved from UAV with those retrieved from Sentinel-2 observations. The results show that the two models are comparable, even if Sentinel-2 yields better results. However, challenges remain when using UAV for turbidity monitoring, such as software limitations for mosaics creation over large water bodies. Nevertheless, the high spatial and temporal information can provide insights into the complex water turbidity patterns which characterize floodplains. The method could help land use management to improve the water quality of these ecosystems

Disparities in breastfeeding among U.S. Black mothers: Identification of mechanisms

Objective: Disparities in U.S. breastfeeding rates persist among Black mothers according to birth country and between Black and White mothers, necessitating further investigation of modifiable mediating factors to inform interventions. This study seeks to examine the extent that social, maternal, infant factors and Theory of Planned Behavior (TPB) domains (attitudes, perceived control, and subjective norms) mediate the association of maternal race/birth country and breastfeeding continuation. Methods: A national cohort of 2,050 mothers self-identifying as U.S.-born non-Hispanic Black (n = 689), foreign-born non-Hispanic Black (n = 139), and U.S.-born non-Hispanic White (n = 1,222) was analyzed. Using logistic regression, associations of race/birth country and any/exclusive breastfeeding at 2–6 months were examined. Structural equation modeling was used to determine whether social, maternal, and infant factors and TPB domains mediate these relationships. Results: 40.0% of U.S.-born Black, 82.2% of foreign-born Black, and 57.3% of U.S.-born White mothers reported any breastfeeding at 2–6 months. Compared with U.S.-born Black mothers, odds of any breastfeeding were sevenfold higher among foreign-born Black mothers (odds ratio [OR] = 7.04 95% confidence interval [CI] = 4.80–10.31), which was explained partly by social/maternal/infant factors and TPB domains. Compared with U.S.-born White mothers, any breastfeeding was lower (OR = 0.54, 95% CI = 0.40–0.73) among U.S.-born Black mothers and higher (OR = 3.81, 95% CI = 2.48–5.87) among foreign-born Black mothers; these differences were also mediated by the aforementioned factors. Conclusions: Among Black mothers in the United States, breastfeeding continuation varied substantially by birth country. Promotion of interventions targeting positive attitudes, perceived control, and subjective norms may reduce disparities among Black and between Black and White mothers