Search results for "Muscle"
showing 10 items of 3397 documents
Evaluation of esophagogastric junction relaxation by 4-second Integrated Relaxation Pressure in achalasia using High Resolution Manometry with water-…
2014
Background Relaxation of the esophagogastric junction (EGJ) is now evaluated calculating 4-second integrated relaxation pressure (4-s IRP) by high resolution manometry (HREPT). Solid-state catheters have been used to define abnormal values. Our aim was to evaluate 4-s IRP in esophageal achalasia using HREPT with perfused catheters. Methods From June 2009 to June 2013, 936 HREPT studies have been performed in our unit. Of these, 194 patients having treated achalasia were excluded. Control group was constituted by 695 patients without achalasia, and 47 patients with untreated achalasia constituted the study group. HREPT was performed with water-perfused catheters. To establish the cut-off val…
Role of endothelium and calcium channels in endothelin-induced contraction of human cerebral arteries
1990
Endothelin constricted human isolated cerebral arteries in a concentration-dependent manner. The maximal tension developed, as well as EC50 values were similar in arteries with and without endothelium. Removal of extracellular calcium or addition of the calcium antagonist nicardipine (10(-6)M), attenuated but did not abolish responses to endothelin. These experiments show that the endothelin-induced contraction in human cerebral arteries is not linked to the presence of intact endothelial cells. The data also show that the contractile effects of endothelin cannot be explained solely by an action on voltage-dependent calcium channels.
Gait-dependent motor memory facilitation in covert movement execution
2004
In the current study, we examined whether sensorimotor information stored in short-term memory may influence the temporal features between overt and covert execution of human locomotor movements and, furthermore, to examine to what extent such influence may depend on the ongoing gait activity. The subjects (n=20) who participated in the experiment were separated in two groups and instructed to walk (overt execution) or imagine walking (covert execution) along three locomotor paths: horizontal, uphill and downhill. The subjects of the first group, labeled in block, performed all the covert trials before executing the corresponding overt trials, while the subjects of the second group, labeled…
Exogenous glucagon-like peptide-1 reduces contractions in human colon circular muscle.
2014
Glucagon-like peptide 1 (GLP1) is a naturally occurring peptide secreted by intestinal L-cells. Though its primary function is to serve as an incretin, GLP1 reduces gastrointestinal motility. However, only a handful of animal studies have specifically evaluated the influence of GLP1 on colonic motility. Consequently, the aims of this study were to investigate the effects induced by exogenous GLP1, to analyze the mechanism of action, and to verify the presence of GLP1 receptors (GLP1Rs) in human colon circular muscular strips. Organ bath technique, RT-PCR, western blotting, and immunofluorescence were used. In human colon, exogenous GLP1 reduced, in a concentration-dependent manner, the ampl…
Extensor digitorum brevis muscle flap for lower extremity coverage in a context of posttraumatic sepsis.
2019
Abstract Introduction Traumatic injuries to the distal quarter of the leg present a significant risk of skin necrosis and exposure of the underlying fracture site or the osteosynthesis material that often result in bone and joint infection. In the case of small or medium-sized bone exposure, local muscles may be one of the best options for lower extremity coverage. We describe our experience using the extensor digitorum brevis muscle flap in a context of posttraumatic bone and joint infection in fourteen patients. Our main objective was to assess the outcomes and the donor-site morbidity of the extensor digitorum brevis muscle flap. Materials and methods A single-center retrospective study …
Skeletal muscle fibre types, enzyme activities and physical performance in young males and females
1978
Differences in skeletal muscle characteristics, metabolic profiles and functional performance between males and females were investigated using young (15--24 yrs) male and female twins as subjects. The comparison included such variables as anthropometry, muscle strength, mechanical power, maximum oxygen uptake, electrical activation of muscle, muscle fibre composition (m. vastus lateralis), and activities of several skeletal muscle enzymes. The results disclosed the following primary differences between males and females: In the various functional tests the performance of females was from 61.1 to 84.6% of that in males; distribution of slow twitch fibres in m. vastus lateralis of the female…
Motor Unit Firing Behaviour of Soleus Muscle in Isometric and Dynamic Contractions
2012
Introduction. Understanding the detailed control of human locomotion and balance can be improved, when individual motor units can be isolated and their firing rates followed in natural movement of large, fuctionally important muscles. For this reason the present study investigated the motor unit discharge rate (MUDR) in isometric and dynamic contractions of the soleus muscle. Methods: Eleven males performed isometric (10–100% MVC) and dynamic (10–40% MVC) plantar flexions. Intramuscular EMG was measured from Soleus with bipolar wire-electrodes and decomposed with custom built “Daisy” software. Results. The Soleus MUDR was significantly higher in concentric compared to isometric or eccentric…
Multi-channel electromyography during maximal isometric and dynamic contractions.
2013
Motor unit behavior differs between contraction types at submaximal contraction levels, however is challenging to study during maximal voluntary contractions (MVCs). With multi-channel surface electromyography (sEMG), mean physiological characteristics of the active motor units can be extracted. Two 8-electrode sEMG arrays were attached on biceps brachii muscle (one on each head) to examine behavior of sEMG variables during isometric, eccentric and concentric MVCs of elbow flexors in 36 volunteers. On average, isometric (364 ± 88N) and eccentric (353 ± 74N) MVCs were higher than concentric (290 ± 73N) MVC (p0.001). Mean muscle fiber conduction velocity (CV) was highest during eccentric MVC …
Neuromuscular Fatigue Following Isometric Contractions with Similar Torque Time Integral
2014
International audience; Torque time integral (TTI) is the combination of intensity and duration of a contraction. The aim of this study was to compare neuromuscular alterations following different isometric sub-maximal contractions of the knee extensor muscles but with similar TTI. Sixteen participants performed 3 sustained contractions at different intensities (25 %, 50 %, and 75 % of Maximal Voluntary Contraction (MVC) torque) with different durations (68.5 +/- 33.4 s, 35.1 +/- 16.8 s and 24.8 +/- 12.9 s, respectively) but similar TTI value. MVC torque, maximal voluntary activation level (VAL), M-wave characteristics and potentiated doublet amplitude were assessed before and immediately a…
Impaired action potential conduction at high force levels after eccentric exercise
2010
High-density surface electromyography was used to examine whether gross sarcolemmal function is impaired in m. biceps brachii after intensive eccentric elbow flexor exercise, when measured at wide range of isometric contraction levels. Root mean square (RMS), mean power frequency (MNF) and mean muscle fibre conduction velocity (CV) were calculated before and up to four days post-exercise. Maximal isometric voluntary (MVC) force decreased by 21.3+/-5.6% two hours after exercise, and by 12.6+/-11.1% two days post-exercise. CV and MNF decreased both during MVC (CV from 4.1+/-0.3m/s to 3.8+/-0.4m/s and MNF from 92.6+/-10 Hz to 85.2+/-11 Hz) and during electrically evoked maximal M-wave (CV from…