Early skin-to-skin contact (SSC), beginning in the delivery room, provides myriad health benefits for mother and baby. Early SSC in the delivery room is the standard of care for healthy neonates following both vaginal and cesarean delivery. However, there is little published evidence on the safety of this practice in infants with congenital anomalies requiring immediate postnatal evaluation, including critical congenital heart disease (CCHD).
View Article and Find Full Text PDFU.S. military troops are exposed to mosquito-borne pathogens when deployed to endemic regions.
View Article and Find Full Text PDFBackground: There are few evidence-based interventions for long COVID; however, holistic approaches supporting recovery are advocated. We assessed whether an online breathing and wellbeing programme improves health related quality-of-life (HRQoL) in people with persisting breathlessness following COVID-19.
Methods: We conducted a parallel-group, single-blind, randomised controlled trial in patients who had been referred from one of 51 UK-based collaborating long COVID clinics.
Motor racing is a physically and mentally demanding sport, associated with a high degree of risk for drivers. Hence, driving simulation provides a safe alternative to explore the impact acute physiological perturbations (e.g.
View Article and Find Full Text PDFMotor-racing drivers are often exposed to hot environments and may be susceptible to fluid loss and hydration issues, which could influence driving performance. This study assessed the effect of dehydration and heat stress on performance during a short, simulated motor-racing task. Nine healthy males (age: 26.
View Article and Find Full Text PDFNitric oxide is generated in skeletal muscle with activity and decreases Ca sensitivity of the contractile apparatus, putatively by nitrosylation of an unidentified protein. We investigated the mechanistic basis of this effect and its relationship to the oxidation-induced increase in Ca sensitivity in mammalian fast-twitch (FT) fibers mediated by glutathionylation of Cys134 on fast troponin I (TnI). Force-[Ca] characteristics of the contractile apparatus in mechanically skinned fibers were assessed by direct activation with heavily Ca-buffered solutions.
View Article and Find Full Text PDFThis study investigated the effect of taurine and β-alanine supplementation on muscle function and muscle taurine transporter (TauT) protein expression in mdx mice. Wild-type (WT) and mdx mice (5 months) were supplemented with taurine or β-alanine for 4 weeks, after which in vitro contractile properties, fatigue resistance and force recovery, and the expression of the TauT protein and proteins involved in excitation-contraction (E-C) coupling were examined in fast-twitch muscle. There was no difference in basal TauT protein expression or basal taurine content between mdx than WT muscle.
View Article and Find Full Text PDFIntroduction: Numerous studies have shown that nicotine (NIC) can enhance the reinforcing effects of non-NIC stimuli through a nonassociative mechanism. To date, it is unclear whether NIC reinforcement enhancement serves to increase behaviors motivated by rewarding stimuli only, or whether NIC potentiates behavior motivated by all stimuli, regardless of valence.
Methods: The current study used a place conditioning procedure to examine whether acute NIC injection modulates avoidance of an environment previously associated with an aversive stimulus.
Oxidation can decrease or increase the Ca2+ sensitivity of the contractile apparatus in rodent fast-twitch (type II) skeletal muscle fibres, but the reactions and molecular targets involved are unknown. This study examined whether increased Ca2+ sensitivity is due to S-glutathionylation of particular cysteine residues. Skinned muscle fibres were directly activated in heavily buffered Ca2+ solutions to assess contractile apparatus Ca2+ sensitivity.
View Article and Find Full Text PDFAm J Physiol Heart Circ Physiol
February 2011
Calsequestrin 2 (CSQ2) is generally regarded as the primary Ca2+-buffering molecule present inside the sarcoplasmic reticulum (SR) in cardiac cells, but findings from CSQ2 knockout experiments raise major questions about its role and necessity. This study determined the absolute amount of CSQ2 present in cardiac ventricular muscle to gauge its likely influence on SR free Ca2+ concentration ([Ca2+]) and maximal Ca2+ capacity. Ventricular tissue from hearts of freshly killed sheep was examined by SDS-PAGE without any fractionation, and CSQ2 was detected by Western blotting; this method avoided the >90% loss of CSQ2 occurring with usual fractionation procedures.
View Article and Find Full Text PDFS-Nitrosoglutathione (GSNO) is generated in muscle and may S-glutathionylate and/or S-nitrosylate various proteins involved in excitation–contraction (EC) coupling, such as Na+-K+-ATPases, voltage-sensors (VSs) and Ca2+ release channels (ryanodine receptors,RyRs), possibly changing their properties. Using mechanically skinned fibres from rat extensor digitorum longus muscle, we sought to identify which EC coupling processes are most susceptible to GSNO-modulated changes and whether these changes could be important in muscle function and fatigue. For comparison, we examined the effect of other oxidation, nitrosylation, or glutathionylation treatments (S-nitroso-N-acetyl-penicillamine (SNAP), hydrogen peroxide,2,2-dithiodipyridine and reduced glutathione) on twitch and tetanic force, action potential (AP) repriming, sarcoplasmic reticulum (SR) Ca2+ loading and leakage, and contractile apparatus properties.
View Article and Find Full Text PDFOxidative modification of contractile proteins is thought to be a key factor in muscle weakness observed in many pathophysiological conditions. In particular, peroxynitrite (ONOO(-)), a potent short-lived oxidant, is a likely candidate responsible for this contractile dysfunction. In this study ONOO(-) or 3-morpholinosydnonimine (Sin-1, a ONOO(-) donor) was applied to rat skinned muscle fibers to characterize the effects on contractile properties.
View Article and Find Full Text PDFExtraction of high quality RNA is paramount to successful RT-PCR, and here, a method proven optimal for skeletal muscle is described. While this method described is for use with skeletal muscle, it could be suitable for other types of mammalian tissue also. This method describes an approach to extract high quality RNA with minimal degradation and the subsequent analysis of that RNA in preparation for RT-PCR.
View Article and Find Full Text PDFObjective: Myocardial infarction (MI) is a serious complication of atherosclerosis associated with increasing mortality attributable to heart failure. Activation of phosphoinositide 3-kinase [PI3K(p110 alpha)] is considered a new strategy for the treatment of heart failure. However, whether PI3K(p110 alpha) provides protection in a setting of MI is unknown, and PI3K(p110 alpha) is difficult to target because it has multiple actions in numerous cell types.
View Article and Find Full Text PDFThis study used purified calsequestrin 1 and AMP kinase (AMPK) proteins to demonstrate how Western blotting outcomes can be influenced when either the density of proteins detected lie within a nonproportional region of a standard curve or a standard curve is not taken into account for data analyses. It outlines the likelihood of true changes being overlooked through the simple mistake of using band density alone and/or through analyzing too much sample. To demonstrate this, extrapolation of a typical linear, although nonproportional, standard curve resulted in approximately fourfold error.
View Article and Find Full Text PDFCaveolin-3, the muscle-specific isoform of the caveolae-associated protein caveolin, is often thought to be localized exclusively in the surface membrane in mature fibers and associated with transverse (t)-tubular system only transiently during development. Skeletal muscle fibers present a model where the surface membrane (sarcolemma) can be completely separated from the cell by mechanical dissection. Western blotting of matching portions of individual fibers from adult rat muscle in which the sarcolemma was either removed (skinned segment), or left in place (intact segment), revealed that > or = 70% of caveolin-3 is actually located deeper in the fiber rather than in the sarcolemma itself.
View Article and Find Full Text PDFWhilst calsequestrin (CSQ) is widely recognized as the primary Ca2+ buffer in the sarcoplasmic reticulum (SR) in skeletal muscle fibres, its total buffering capacity and importance have come into question. This study quantified the absolute amount of CSQ isoform 1 (CSQ1, the primary isoform) present in rat extensor digitorum longus (EDL) and soleus fibres, and related this to their endogenous and maximal SR Ca2+ content. Using Western blotting, the entire constituents of minute samples of muscle homogenates or segments of individual muscle fibres were compared with known amounts of purified CSQ1.
View Article and Find Full Text PDFObjective: Insulin resistance associated with obesity and diabetes is ameliorated by specific overexpression of GLUT4 in skeletal muscle. The molecular mechanisms regulating skeletal muscle GLUT4 expression remain to be elucidated. The purpose of this study was to examine these mechanisms.
View Article and Find Full Text PDFPhysical activity protects against cardiovascular disease, and physiological cardiac hypertrophy associated with regular exercise is usually beneficial, in marked contrast to pathological hypertrophy associated with disease. The p110alpha isoform of phosphoinositide 3-kinase (PI3K) plays a critical role in the induction of exercise-induced hypertrophy. Whether it or other genes activated in the athlete's heart might have an impact on cardiac function and survival in a setting of heart failure is unknown.
View Article and Find Full Text PDFObes Res Clin Pract
January 2007
Objective: To investigate the effects of leptin on the mRNA abundance of key genes involved in fatty acid oxidation and mitochondrial biogenesis in cultured skeletal muscle myotubes derived from lean and obese individuals.
Research Methods And Procedures: Rectus abdominus muscle biopsies were obtained from surgical patients to establish primary skeletal muscle cell cultures. Two distinct primary cell culture groups were established (Lean and Obese) n = 7 in each group.
Objective: This study aimed to investigate the regulation of adiponectin receptors 1 (AdipoR1) and 2 (AdipoR2) gene expression in primary skeletal muscle myotubes, derived from human donors, after exposure to globular adiponectin (gAd) and leptin.
Research Methods And Procedures: Four distinct primary cell culture groups were established [Lean, Obese, Diabetic, Weight Loss (Wt Loss); n = 7 in each] from rectus abdominus muscle biopsies obtained from surgical patients. Differentiated myotube cultures were exposed to gAd (0.
Characterization of expression of, and consequently also the acute exercise effects on, Na(+),K(+)-ATPase isoforms in human skeletal muscle remains incomplete and was therefore investigated. Fifteen healthy subjects (eight males, seven females) performed fatiguing, knee extensor exercise at approximately 40% of their maximal work output per contraction. A vastus lateralis muscle biopsy was taken at rest, fatigue and 3 and 24 h postexercise, and analysed for Na(+),K(+)-ATPase alpha(1), alpha(2), alpha(3), beta(1), beta(2) and beta(3) mRNA and crude homogenate protein expression, using Real-Time RT-PCR and immunoblotting, respectively.
View Article and Find Full Text PDFThe endothelial cell protein C receptor (EPCR) binds to both protein C and activated protein C (APC) with similar affinity. Removal of the Gla domain of protein C results in the loss of most of the binding affinity. This observation is compatible with at least two models: 1) the Gla domain of protein C interacts with phospholipid on cell surfaces to stabilize interaction with EPCR or 2) the Gla domain of protein C makes specific protein-protein interactions with EPCR.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
September 1996
Protein C activation on the surface of the endothelium is critical to the negative regulation of blood coagulation. We now demonstrate that monoclonal antibodies that block protein C binding to the endothelial cell protein C receptor (EPCR) reduce protein C activation rates by the thrombin-thrombomodulin complex on endothelium, but that antibodies that bind to EPCR without blocking protein C binding have no effect. The kinetic result of blocking the EPCR-protein C interaction is an increased apparent Km for the activation without altering the affinity of thrombin for thrombomodulin.
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