Search results for "RAM"
showing 10 items of 35643 documents
Soleus and lateral gastrocnemius H-reflexes during standing with unstable footwear
2015
Introduction: Unstable footwear has been shown to increase lower extremity muscle activity, but the reflex response to perturbations induced by this intervention is unknown. Methods: Twenty healthy subjects stood in stable and unstable footwear conditions (presented randomly) while H-reflex amplitude and background muscle activity were measured in the soleus and lateral gastrocnemius (LG) muscles. Results: Wearing unstable footwear resulted in larger H-reflexes (normalized to the maximal M-wave) for the LG (+12%; P = 0.025), but not for the soleus (+4%; P > 0.05). Background activity of both muscles was significantly higher in the unstable condition. Conclusions: The H-reflex facilitation o…
Isolated human chorionic vascular reactivity: Technical considerations for fresh preparations
1998
1. 1. Sixty chorionic vascular rings from normal term placentas were immersed in an organ bath for isometric tension recording to study (A) the contractile response to 120 mM of potassium chloride (KCI) after adjustment and equilibration to 1–5 g of passive tension; and (B) the concentration-response curve to KCI after adjustment and equilibration to the optimal passive tension. 2. 2. Adjustment to 4 g of passive tension elicited the maximal (P<0.007) and the latest (P<0.006) KCl-induced contraction among arterial rings. Venous rings showed the greatest contraction when adjusted to 3 g, but the differences were not significant except when compared to 1 g of passive tension (P<0.03). 3. 3. T…
Sonographische Darstellbarkeit der Gallenwege und Beurteilbarkeit der Gallenblasenkinetik bei gesunden Neugeborenen
2008
The gallbladder and the biliary tract of 85 neonates were sonographically examined, in the fasting state. The gallbladder was detectable in all neonates and showed a measurable contraction. Two types of biliary contraction could be observed: a concentric contraction of length, depth and width (concentric type) or a contraction of depth and width (collapse type). The grade of postprandial contraction was independent of the level of serum bilirubin. Furthermore, sonographic criteria were established allowing the differentiation of the bile ducts and their discrimination from hepatic arteries.
Alteration of Esophageal Peristalsis by Pentagastrin in Patients with Diffuse Esophageal Spasm
1975
Although it has been shown that gastrin and gastric alkalinization affect the lower esophageal sphincter, in vivo studies have not demonstrated a measurable effect of pentagastrin on esophageal peristalsis. In 9 patients with diffuse esophageal spam and in 10 control subjects esophageal peristalsis was recorded before and after pentagastrin infections. Subcutaneous pentagastrin increased peak amplitude significantly more in patients, 31.2 +/- 8.1 mm Hg (mean +/- S.E.M.), than in controls, 12.1 +/- 5.1 mm Hg (P less than 0.02). Max. duration of contraction waves in patients showed a rise of 11.3 +/- 2.7 sec as compared to controls, 1.9 +/- 0.9 sec (P less than 0.01). The effect of pentagastr…
Changes in motor unit characteristics after eccentric elbow flexor exercise
2010
Morphological evidence suggests that fast-twitch fibers are prone to disruption of their membrane structures by eccentric exercise. However, it is unclear how this is reflected in the discharge rate and action potential propagation of individual motor units, especially at high contraction levels. High-density surface electromyograms were recorded from biceps brachii muscle and decomposed to individual motor unit action potentials at isometric contraction levels between 10% and 75% of maximal voluntary contraction (MVC) before intermittent maximal elbow flexor eccentric exercise, and two hours (2H), two days (2D) and four days (4D) post-exercise. Maximal voluntary force decreased by 21.3±5.6…
Increased Joint Mobility Is Associated With Impaired Transversus Abdominis Contraction.
2020
Mitchell, UH, Owen, PJ, Rantalainen, T, and Belavý, DL. Increased joint mobility is associated with impaired transversus abdominis contraction. J Strength Cond Res 36(9): 2472-2478, 2022-Increased joint mobility is a risk factor for joint injury, but muscle function may be able to compensate for it. Current evidence suggests reduced force production capacity in people with hypermobility. However, little is known about the lumbar spine. The purpose of this cross-sectional study was to assess whether there was a link between joint mobility and transverse abdominis and multifidus muscles contraction, muscles ascribed a core-stability role. Using a modified quantitative version of the Beighton …
Changes in gallbladder motor function during the female cycle — a risk factor leading to gallstone formation?
1982
The gallbladder volume of eight women with stable cycles was determined by sonography. Furthermore, gallbladder contraction — following an orally administered fatty meal and the spontaneous refilling of the empty gallbladder — was quantitatively examined. The formula of a rotation ellipsoid, which has been proven to be adequately accurate in in vitro studies, was used for calculating the gallbladder volume. In the gestagen phase (21st or 22nd day) the intraindividual studies showed greater fasting volumes, higher residual volumes after contraction, slower gallbladder emptying, and retarded refilling of the empty gallbladder as compared to the estrogen phase (12th or 13th day). The hormonall…
Changes in neural drive to calf muscles during steady submaximal contractions after repeated static stretches
2021
Key points: Repeated static-stretching interventions consistently increase the range of motion about a joint and decrease total joint stiffness, but findings on the changes in muscle and connective-tissue properties are mixed. The influence of these stretch-induced changes on muscle function at submaximal forces is unknown. To address this gap in knowledge, the changes in neural drive to the plantar flexor muscles after a static-stretch intervention were estimated. Neural drive to the plantar flexor muscles during a low-force contraction increased after repeated static stretches. These findings suggest that adjustments in motor unit activity are necessary at low forces to accommodate reduct…
Impact of the COVID-19 pandemic on hospitalizations for acute coronary syndromes: a multinational study
2021
Abstract Background COVID-19 has challenged the health system organization requiring a fast reorganization of diagnostic/therapeutic pathways for patients affected by time-dependent diseases such as acute coronary syndromes (ACS). Aim To describe ACS hospitalizations, management, and complication rate before and after the COVID-19 pandemic was declared. Design Ecological retrospective study. Methods: We analyzed aggregated epidemiological data of all patients &gt; 18 years old admitted for ACS in twenty-nine hub cardiac centers from 17 Countries across 4 continents, from December 1st, 2019 to April 15th, 2020. Data from December 2018 to April 2019 were used as historical period. Results…
Evaluation of the UP4FUN Intervention: A Cluster Randomized Trial to Reduce and Break Up Sitting Time in European 10-12-Year-Old Children
2015
Background The UP4FUN intervention is a family-involved school-based intervention aiming at reducing and breaking up sitting time at home (with special emphasis on screen time), and breaking up sitting time in school among 10–12 year olds in Europe. The purpose of the present paper was to evaluate its short term effects. Methodology/Principal Findings A total of 3147 pupils from Belgium, Germany, Greece, Hungary and Norway participated in a school-randomized controlled trial. The intervention included 1–2 school lessons per week for a period of six weeks, along with assignments for the children and their parents. Screen time and breaking up sitting time were registered by self-report and to…