A mitochondrial-targeted antioxidant improves myofilament Ca2+ sensitivity during prolonged low frequency force depression at low PO2

Abstract

Skeletal muscle can develop a prolonged low frequency-stimulation force depression (PLFFD) following fatigue-inducing contractions. Increased levels of reactive oxygen species (ROS) have been implicated in the development of PLFFD. During exercise the skeletal muscle intracellular PO₂ decreases to relatively low levels, and can be further decreased when there is an impairment in O₂ diffusion or availability, such as in certain chronic diseases and during exercise at high altitude. Since ROS generation by mitochondria is elevated at very low PO₂ in cells, we tested the hypothesis that treatment of muscle fibres with a mitochondrial-targeted antioxidant at a very low, near hypoxic PO₂, can attenuate PLFFD. We treated intact single fibres from mice with the mitochondrial-specific antioxidant SS31, and measured force development and intracellular [Ca²⁺] 30 min after fatigue at an extracellular PO₂ of ∼5 Torr. After 30 min following the end of the fatiguing contractions, fibres treated with SS31 showed significantly less impairment in force development compared to untreated fibres at submaximal frequencies of stimulation. The intracellular peak [Ca²⁺] transients (peak [Ca²⁺]_c) were equally decreased in both groups compared to pre-fatigue values. The combined force and peak [Ca²⁺]_c data demonstrated that myofibrillar Ca²⁺ sensitivity was diminished in the untreated fibres 30 min after fatigue compared to pre-fatigue values, but Ca²⁺ sensitivity was unaltered in the SS31 treated fibres. These results demonstrate that at a very low PO₂, treatment of skeletal muscle fibres with a mitochondrial antioxidant prevents a decrease in the myofibrillar Ca²⁺ sensitivity, which alleviates the fatigue induced PLFFD.

This article is protected by copyright. All rights reserved

from Physiology via xlomafota13 on Inoreader http://ift.tt/2DwQvSh
via IFTTT

Fla. hospital system implements telemedicine program

The NCH Healthcare System launched a "virtual visit" program, enabling patients to have a telemedicine visit any time of day or night for non-emergency issues

from EMS via xlomafota13 on Inoreader http://ift.tt/2D7peJ4
via IFTTT

The Health Behaviors of Ethnically Diverse Women at Increased Risk of Gestational Diabetes: The Behaviors Affecting Baby and You (B.A.B.Y.) Study

Abstract

Objectives Cigarette smoking, low physical activity, and sedentary behavior are modifiable risk factors for adverse pregnancy outcomes. However, only one study has evaluated predictors of these health risk behaviors among women at high risk for gestational diabetes mellitus (GDM). Therefore, our goal was to examine predictors of smoking, low physical activity, and sedentary behavior during pregnancy in an ethnically diverse high risk cohort. Methods This cross-sectional analysis utilized baseline data from the Behaviors Affecting Baby and You (B.A.B.Y.) study conducted among prenatal care patients at high risk for GDM (personal history of GDM or family history of diabetes and body mass index [BMI] ≥ 25 kg/m²). Smoking was assessed using questions from the Pregnancy Risk Assessment Monitoring System questionnaire and sedentary behavior (top vs. lower quartiles) and moderate/vigorous physical activity (bottom vs. upper quartile) via the Pregnancy Physical Activity Questionnaire. Results Participants (n = 400) enrolled at a mean of 12.4 (SD 3.6) weeks gestation. A total of 150 (44.1%) engaged in one, 37 (10.9%) in two, and 4 (1.2%) in three risk behaviors. Lower household income and not having children at home were each associated with a 2–6 fold increased odds of smoking, high sedentary behavior, and engaging in at least one risk behavior. Being married, Hispanic or of younger age was associated with a 2–6 fold reduced odds of smoking. BMI and personal history of GDM were not associated with risk behaviors. Conclusions for Practice Findings help characterize high risk groups and inform prenatal interventions targeting these health risk behaviors.

from Health via xlomafota13 on Inoreader http://ift.tt/2B3vgog
via IFTTT

Runs of homozygosity: windows into population history and trait architecture

Runs of homozygosity: windows into population history and trait architecture

Runs of homozygosity: windows into population history and trait architecture, Published online: 15 January 2018; doi:10.1038/nrg.2017.109

Runs of homozygosity (ROH) are genomic regions of homozygosity where the identical maternal and paternal haplotypes are descended from a shared common ancestor, and they are well known to occur as a result of inbreeding. This article discusses strategies for detecting ROH, their underappreciated prevalence across diverse outbred populations and implications for complex traits and human disease.

from Genetics via xlomafota13 on Inoreader http://ift.tt/2mF2NAJ
via IFTTT

Elevated sympathetic vasomotor outflow in response to increased inspiratory muscle activity during exercise is less in young women compared with men

Abstract

We compared changes in muscle sympathetic nerve activity (MSNA) and cardiovascular variables during leg cycle exercise with increased inspiratory muscle resistance in men and women. We hypothesized that sympathetic vasomotor outflow during exercise with increased inspiratory resistance would be attenuated in young women compared with age-matched men. Eight women and seven men completed the study. The subjects performed two 10-min exercise bouts at 40% peak oxygen uptake using a cycle ergometer in a semirecumbent position [spontaneous breathing for 5 min and voluntary hyperventilation with or without inspiratory resistive breathing for 5 min (breathing frequency: 50 breaths min⁻¹ with a 50% duty cycle, inspiratory resistance: 30% of maximal inspiratory pressure)]. Mean arterial blood pressure (MAP) was acquired using finger photoplethysmography. MSNA was recorded via microneurography of the right median nerve at the cubital fossa. During leg cycle exercise with inspiratory resistive breathing, MSNA burst frequency (BF) was increased accompanied by an increase in MAP both in men and women. Women, compared with men, had less of an increase in MAP (Women: +22.8 ± 12.3 vs. Men: +32.2 ± 5.4 mmHg, P < 0.05) and MSNA BF (Women: +9.6 ± 2.9 vs. Men: +14.6 ± 6.4 bursts min⁻¹, P < 0.05). These results suggest that the attenuated inspiratory muscle-induced metaboreflex during exercise in young women is partially attributed to a lesser sympathetic vasomotor outflow compared with men.

This article is protected by copyright. All rights reserved

from Physiology via xlomafota13 on Inoreader http://ift.tt/2EL7yQa
via IFTTT

Healthcare and Social Services Providers Who Serve Sexual and Gender Minorities in a U.S.-Mexico Border City

Abstract

Sexual and gender minorities, including lesbian, gay, bisexual, transgender, and queer (LGBTQ) individuals, experience barriers to healthcare as a result of stigma, discrimination, and poor cultural competence by healthcare and social services providers (HCSSP). The purpose of the study is to increase access to care and services for the LGBTQ community in a U.S.-Mexico border city by identifying LGBTQ-friendly HCSSP. A survey, developed based on concerns voiced in a predominantly Hispanic LGBTQ community, was administered to HCSSP and used to create a referral list, "The Purple Pages of El Paso" (PPoEP). Overall, 77 HCSSP have responded and 43 are included in the most recent version of the PPoEP. This model for developing a referral list of providers can be adapted in areas where LGBTQ communities face similar barriers to care and services. To be effective in reducing barriers to care, PPoEP must be updatable and sustainable.

from Health via xlomafota13 on Inoreader http://ift.tt/2B1I2Ul
via IFTTT

Runs of homozygosity: windows into population history and trait architecture

from Genetics via xlomafota13 on Inoreader http://ift.tt/2DwVvXd
via IFTTT