Introduction Little is known about the relationship between left atrium (LA) volumes and contractility features along cardiac cycle. The present study aimed to assess, by three-dimensional speckle-tracking echocardiography (3DSTE), correlations LA volumes, volume-based functional properties, strains during cycle in healthy adults. Methods We included 217 adult volunteers (mean age 33.4 ± 12.7 y...

KAPOPORT, STANLEY I., AND JEANNETTE M. BIDINGER. Eject of stretch on contractility and ionic contents of the sartorius muscle of Rana pipiens. Am. J. Physiol. 226(Z) : 452-457’ 1974.-When sartorius muscles of frogs are soaked in Ringer at room temperature, they gain Na, lose K, and lose contractility with time. These changes are retarded by stretching the muscles to ZO-30Y0 of their rest length...

Acto-myosin contractility in carcinoma-associated fibroblasts leads to assembly of the tumor extracellular matrix. The pro-inflammatory cytokine LIF governs fibroblast activation in cancer by regulating the myosin light chain 2 activity. So far, however, how LIF mediates cytoskeleton contractility remains unknown. Using phenotypic screening assays based on knock-down of LIF-dependent genes in f...

The HS-1 associated protein X-1 (HAX-1) is a ubiquitously expressed protein that protects cardiomyocytes from programmed cell death. Here we identify HAX-1 as a regulator of contractility and calcium cycling in the heart. HAX-1 overexpression reduced sarcoplasmic reticulum Ca-ATPase (SERCA2) pump activity in isolated cardiomyocytes and in vivo, leading to depressed myocyte calcium kinetics and ...

Myocardial intracellular pH was measured in a perfused rainbow trout, Salmo gairdneri, with DMO (5,5-dimethyl-2,4-oxazlidinedione), to test the hypothesis that catecholamines promote active regulation of myocardial pH in order to protect contractility during a respiratory acidosis comparable to that observed after exercise. Under control conditions (extracellular pH = 8.0; PCO2 = 2 Torr), myoca...

Observations were made on the Ca-sensitivity of glycerinated muscle bundles from dog intestine. The results obtained were as follows 1) The Ca-sensitivity of glycerinated muscle bundles depends on theduration of glycerol extraction. With long-term extraction, the muscle bundles lost a large part of the Ca-sensitivity of the ATP contractility. 2) When the bundles that had a typical Ca-sensitivit...

In this work, we combine genetic perturbation, time-lapse imaging and quantitative image analysis to investigate how pulsatile actomyosin contractility drives cell oscillations, apical cell contraction and tissue closure during morphogenesis of the amnioserosa, the main force-generating tissue during the dorsal closure in Drosophila We show that Myosin activity determines the oscillatory and co...

An understanding of the physiological and pharmacological factors regulating myometrial contractility is essential to development of therapeutic interventions aimed at addressing the clinical disorders associated with labor. Preterm labor and dystocia are the clinical conditions associated with dysfunctional myometrial contractility. Both conditions are seen in increased frequency in the presen...

Estimation of ventricular contractility is clinically important in diagnosing cardiac dysfunction in the critically ill. However, experimental assessment of indexes of ventricular contractility, such as the end-systolic pressure-volume relationship requires a highly invasive maneuver. This research describes the use of a previously validated cardiovascular system (CVS) model and identification ...

A 30 year old woman with a lifelong history of severe, recurrent, vasovagal syncope became asystolic for 30 seconds after 37 minutes of 60 degrees head-up tilt. During early tilt, sympathetic activity, heart rate, left ventricular contractility, and cardiac output increased. Mean blood pressure was initially maintained. Presyncope was associated with maximal contractility and bradycardia despit...