Search results for "Skeletal muscle"

Prooxidative toxicity and selenoprotein suppression by cerivastatin in muscle cells

2012

Statins are the most widely used drugs for the treatment of hypercholesterolemia. In spite of their overall favorable safety profile, they do possess serious myotoxic potential, whose molecular origin has remained equivocal. Here, we demonstrate in cultivated myoblasts and skeletal muscle cells that cerivastatin at nanomolar concentrations interferes with selenoprotein synthesis and evokes a heightened vulnerability of the cells toward oxidative stressors. A correspondingly increased vulnerability was found with atorvastatin, albeit at higher concentrations than with cerivastatin. In selenium-saturated cells, cerivastatin caused a largely indiscriminate suppression of selenoprotein biosynth…

Hormonal and nutritional control of L‐carnitine uptake in myoblastic C2C12 cells

2008

L-Carnitine plays an important role in skeletal muscle bioenergetics, and its bioavailability and thus its import may be crucial for muscle function. We studied the effect of thyroid hormone, insulin, and iron overload, hormones and nutrients known to alter muscle metabolism, on L-carnitine import into C2C12 cells. We report here L-carnitine uptake is increased by thyroid hormones and decreased by iron. Insulin was found to be ineffective in altering the L-carnitine uptake.

The Effects of Restriction Pressures on the Acute Responses to Blood Flow Restriction Exercise

2019

Purpose: No current guidelines or recommendations exist informing the selection of restriction pressure during blood flow restriction exercise (BFRE). Moreover, the effects of specific relative restriction pressures on the acute muscle, metabolic and cardiopulmonary responses to BFRE are unclear. The purpose of this study was to characterize these acute responses at different levels of restriction pressure. Methods: Participants (n = 10) completed rhythmic isometric knee extension exercise across five experimental trials in a balanced randomized order. Three were BFRE trials {B-40 [restriction pressure set to 40% LOP (total limb occlusion pressure)]; B-60 (60% LOP); and B-80 (80% LOP)) with…

Aestivation Motifs Explain Hypertension and Muscle Catabolism in Experimental Chronic Renal Failure

2020

Chronic renal failure leads to muscle mass loss and hypertension, which according to textbook teaching occur secondary to an inability of the kidneys to excrete solutes and water. We found instead that rats with experimental chronic renal failure constantly lost body water, because their kidneys could not sufficiently concentrate the urine. Physiological adaptation to body water loss, termed aestivation, is an evolutionary conserved survival strategy that relies on complex physiologic-metabolic adjustment across multiple organs to prevent otherwise lethal dehydration. We show that rats with chronic renal failure utilize these ancient water conservation motifs to successfully stabilize their…

Skeletal Muscle Collagen Type 1 mRNA, Prolyl-4-Hydroxylase and Hydroxyproline after Prolonged Physical Training in Hypobaric Hypoxia

1994

Regulation of synthesis of fibrillar collagens in rat skeletal muscle during immobilization in shortened and lengthened positions

2001

Immobilization has been shown to cause muscle atrophy and decreased total collagen synthesis in skeletal muscle. These changes can be counteracted by stretch. The purpose of this study was to find out the early effects of immobilization in shortened and lengthened positions on expression of type I and III collagen at pre- and post-translational level. The mRNA levels of type I and III collagen, prolyl 4-hydroxylase activity, total collagen concentration and the proportions of type I and III collagens were analysed in soleus (SOL), gastrocnemius (GM), extensor digitorum longus and tibialis anterior (TA) muscles during immobilization in shortened and lengthened positions for 1, 3 and 7 days. …

Intestinal ischaemia during cardiac arrest and resuscitation: comparative analysis of extracellular metabolites by microdialysis.

2003

Intestinal ischaemia is a major complication of shock syndromes causing translocation of bacteria and endotoxins and multiple organ failure in intensive care patients. The present study was designed to use microdialysis as a tool to monitor intestinal ischaemia after cardiac arrest and resuscitation in pigs. For this purpose, microdialysis probes were implanted in pig jejunal wall, peritoneum, skeletal muscle and brain, and interstitial fluid was obtained during circulatory arrest (induced by ventricular fibrillation) and after return of spontaneous circulation (ROSC). Cardiac arrest for 4 min caused a prolonged (60 min) reduction of blood flow in jejunal wall, muscle and brain as determine…

The cardinal exercise stopper: Muscle fatigue, muscle pain or perception of effort?

2018

The capacity to sustain high-intensity aerobic exercise is essential for endurance performance. Therefore, it is important to understand what is the factor limiting time to exhaustion (TTE) in healthy and fit adults. In Study 1, maximal voluntary cycling power (MVCP) was measured in 11 volunteers before and immediately after a high-intensity TTE test on cycle ergometer. Cadence was 60 rpm in both the MVCP and TTE tests. Despite a 35% loss in MVCP, power produced during the final MVCP test (mean ± SD 469 ± 111 W) was significantly higher than the power required by the TTE test (269 ± 55 W) (P < 0.001). In Study 2, 12 participants performed a cold pressor test (CPT) to the limit of tolerance …

M-cadherin and its sisters in development of striated muscle

1999

Cadherins are calcium-dependent, transmembrane intercellular adhesion proteins with morphoregulatory functions in the development and maintenance of tissues. In the development of striated muscle, the expression and function of mainly M-, N-, and R-cadherin has been studied so far. While these three cadherins are expressed in skeletal muscle cells, of these only N-cadherin is expressed in cardiac muscle. In this review, M-, N-, and R-cadherin are discussed as important players in the terminal differentiation and possibly also in the commitment of skeletal muscle cells. Furthermore, reports are described which evaluate the essential role of N-cadherin in the formation of heart tissue.

Correlation of skeletal muscle blood oxygenation level-dependent MRI and skin laser doppler flowmetry in patients with systemic sclerosis

2013

Purpose To investigate the origin of skeletal muscle BOLD MRI alterations in patients with systemic sclerosis (SSc) by correlating BOLD MRI T2* signal of calf muscles with microcirculatory blood flow of calf skin measured by laser Doppler flowmetry (LDF). Materials and Methods BOLD MRI (3T) and LDF measurements were performed in 12 consecutive SSc patients (6 women, 6 men; mean age 54.0 ± 10.0 years) and 12 healthy volunteers (4 men, 8 women; mean age 44.7 ± 13.1 years). For both modalities, the same cuff compression paradigm at mid-thigh level was used. LDF datasets were acquired using a PeriScan PIM II Imager (Perimed AB, Stockholm, Sweden) at the upper calf corresponding to the level of …