Search results for "cellular"
showing 10 items of 6449 documents
Stimuli and sensors that initiate skeletal muscle hypertrophy following resistance exercise
2018
One of the most striking adaptations to exercise is the skeletal muscle hypertrophy that occurs in response to resistance exercise. A large body of work shows that a mammalian target of rapamycin complex 1 (mTORC1)-mediated increase of muscle protein synthesis is the key, but not sole, mechanism by which resistance exercise causes muscle hypertrophy. While much of the hypertrophy signaling cascade has been identified, the initiating, resistance exercise-induced and hypertrophy-stimulating stimuli have remained elusive. For the purpose of this review, we define an initiating, resistance exercise-induced and hypertrophy-stimulating signal as “hypertrophy stimulus,” and the sensor of such a s…
Effects of intermittent high frequency electrical stimulation on denervated EDL muscle of rabbit.
1990
This study was performed to determine whether electrical stimulation can retard denervation-induced changes. The denervated extensor digitorum longus of the rabbit, a fast-twitch muscle, was stimulated at a rate mimicking its motoneuron firing pattern. The 100-Hz stimulation given intermittently subjected the muscle to a low mean total daily frequency of 1.6 Hz. Four weeks of stimulation resulted in no effect upon the denervated stimulated muscle. This stimulation protocol, therefore, is unable to substitute for the lost neuronal influence of the nerve. The muscle contralateral to the stimulated side showed physiological changes making it unsuitable to serve as a control.
Lipid peroxidation capacities in the myocardium of endurance-trained rats and mice in vitro.
1992
The endurance-training programme in Experiment 1 (Exp. 1) consisted of a total swimming time of 149–159 h per male Han Wistar rat and in Experiment 2 (Exp. 2) the male NMRI-mice run on a treadmill at a speed of 25 m min-1 1 h per day, 5 days a week for 3 weeks. One group of the rat hearts was perfused with 0.3 mm cumene hydroperoxide (CumOOH) while the others were fractioned (mitochondria, sarcolemma and sarcoplasmic reticulum) and these cell fractions and homogenates were used to determine the total concentration of peroxidative lipids and the susceptibility to lipid peroxidation. The perfusion with CumOOH caused the release of thiobarbituric acid reactive substances (TBARS) into the perfu…
Effects of electrical stimulation pattern on quadriceps force production and fatigue
2014
Introduction: Mixed stimulation programs (MIX) that switch from constant frequency trains (CFT) to variable frequency trains have been proposed to offset the rapid fatigue induced by CFT during electrical stimulation. However, this has never been confirmed with long stimulation patterns, such as those used to evoke functional contractions. The purpose of this study was to test the hypothesis that MIX programs were less fatiguing than CFTs in strength training-like conditions (6-s contractions, 30-min). Methods: Thirteen healthy subjects underwent 2 sessions corresponding to MIX and CFT programs. Measurements included maximal voluntary isometric torque and torque evoked by each contraction. …
Repeated courses of granulocyte colony-stimulating factor in amyotrophic lateral sclerosis: Clinical and biological results from a prospective multic…
2011
Granulocyte colony-stimulating factor (G-CSF) induces a transient mobilization of hematopoietic progenitor cells from bone marrow to peripheral blood. Our aim was to evaluate safety of repeated courses of G-CSF in patients with amyotrophic lateral sclerosis (ALS), assessing disease progression and changes in chemokine and cytokine levels in serum and cerebrospinal fluid (CSF). Twenty-four ALS patients entered an open-label, multicenter trial in which four courses of G-CSF and mannitol were administered at 3-month intervals. Levels of G-CSF were increased after treatment in the serum and CSF. Few and transitory adverse events were observed. No significant reduction of the mean monthly decrea…
Reversible esophageal motor dysfunction in botulism
1985
Two cases of botulism with autonomic and neuromuscular system involvement are presented. In both patients, dryness of the mouth and difficulties in swallowing were predominant symptoms. Esophageal manometry revealed a marked decrease in peristaltic amplitude, which was most pronounced in the upper third of the esophagus. These functional abnormalities returned to normal following recovery from the acute disease.
Effect of gender and obesity on electrical current thresholds
2011
Introduction: In this study we investigated the influence of gender and obesity on electrical current thresholds in an attempt to optimize the application of skeletal muscle electrical stimulation (ES) in clinical practice. Methods: Thirty- two obese and 35 age-matched, non-obese men and women received graded ES to the quadriceps muscle for sensory (detection) and motor (contraction) threshold assessment. Con- comitant pain and tolerance to ES were recorded. Results: Sen- sory threshold was lower in women than in men (P < 0.001), both obese and non-obese. Sensory and motor thresholds were higher in obese than in non-obese subjects (P < 0.05), and body mass index was a strong predictor of mo…
Insulin-like growth factors in chick embryo retina during development.
1996
Evidence exists supporting an important role for insulin-like growth factors (IGFs) during fetal growth. In the present report we performed studies to define whether developing chick retina contains IGFs and whether IGFs play a role in the growth of this tissue. We have shown that both IGF-I and IGF-II are present in chick embryo retina throughout development (7th-18th day). The highest values, when expressed as ng/g of tissue, were found in the youngest retinas studied (7th-9th day) and at 16th-18th day of development. During whole development the content of IGF-II was about two to three times higher than that ascertained for IGF-I. The tissue also contains cell-surface binding for IGFs. H…
Effect of coronary perfusion rate on the hydrolysis of exogenous and endogenous acetylcholine in the isolated heart
1977
1. The effect of perfusion rate on the hydrolysis of acetylcholine in isolated chicken hearts was studied by measuring both the spontaneous and the evoked output of endogenous acetylcholine into the perfusate in response to vagal stimulation and the arterio-venous difference of exogenous acetylcholine. 2. A decrease in the perfusion rate from 30 to 20 and 10 ml/min caused a graded and significant decline of both the spontaneous overflow of acetylcholine and the overflow evoked by stimulation of both vagus nerves (20 Hz, 1 ms, 40V) for 20 min. The spontaneous and evoked overflow at 30 ml/min were 2 and 3 times, respectively, the overflow at 10 ml/min. 3. Physostigmine (10−6M) raised both the…
Release of endogenous 3,4-dihydroxyphenylethylamine and its metabolites from the isolated neurointermediate lobe of the rat pituitary gland. Effects …
1986
: Isolated rat neurointermediate lobes were incubated in vitro. The release of 3,4-dihydroxyphenylethylamine (dopamine, DA), dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), and methoxyphenylethanol (MOPET) was determined by HPLC with electrochemical detection. Under resting conditions, the outflow of metabolites was 35–50 times that of DA. HVA accounted for 50%, DOPAC for 45%, and MOPET for 5% of the metabolites. Although an equivalent of 40–50% of the tissue DA content was released per hour as metabolites, the tissue DA content was not reduced after 110 min of incubation. The spontaneous outflow of DA and its metabolites was not affected by the DA uptake inhibitor GBR 12921 (1…