It has long been accepted that M g A T P is the energy source for contraction. Evidence has also accumulated indicating that M g A T P plays an important role in the regulation of contraction (Weber and Murray, 1973; Inoue and Tonomura , 1974; Godt, 1974; Orentlicher et al., 1977). In an a t tempt to better understand the dual role of ATP in contraction, several researchers have studied the eff...

This study investigations the phenomenon of sustained mechanical alternans (SMA) through the use of quantitative criteria. Discrete analysis is used to demonstrate that the hemodynamic variables during SMA are governed by a simple mathematical relation. The analysis shows that the value of the slope created by the two alternating beats on the stroke volume (SV)-end-diastolic volume (EDV) plane ...

We hypothesized that 10 days of training would enhance cardiac output (CO) and stroke volume (SV) during peak exercise and increase the inotropic response to beta-adrenergic stimulation. Ten subjects [age 26 +/- 2 (SE) yr] trained on a cycle ergometer for 10 days. At peak exercise, training increased O2 uptake, CO, and SV (P < 0.001). Left ventricular (LV) size and function at rest were assesse...

Upon submersion, mammalian divers invariably exhibit a characteristic ‘dive reflex’: the heart slows and the peripheral vessels, supplying blood to muscles and non-vital organs, constrict, thereby prioritising blood flow to the brain. This stereotyped response, dubbed ‘the master switch of life’ by Per Scholander following his pioneering work, imposes unusual demands on the major arteries. The ...

Gravity-driven flow of concentrated suspensions (solid volume fraction ϕ>0.50) of non-brownian spherical particles through a channel contraction at low Reynolds number is studied experimentally. The abrupt change in the flow area at the contraction forms distinct shear-rate regions having different fluid pressures, which are related to the concept of particle pressure. A model involving particl...

Changes in dimensions of the ventricular chambers and the displacement of specific points on the wulls of the heart have been studied by the cinefluorographic technic. The contributions of the various myocardial layers to ventricular ejection have been considered in terms of the anatomic architecture of the heart. The mechanical effectiveness of myocardial contraction is closely related to the ...

IN EXPERIMENTS oti the dog heart-lung preparation which led to the formulation of the well-known "Law of the Heart," Patterson, Piper and Starling observed that when cardiac work was augmented, ventricular volume sometimes increased in the face of a constant left ventricular end-diastolic pressure. These investigators concluded that the strength of myocardial contraction was a function of end-d...

Abstract— Frank-Starling law, which describes a relation between cardiac contraction energy and end-diastolic volume, is of importance, but the detailed mechanism is not quantitatively understood yet. In this paper, the mechanism of a linear relation between end-diastolic volume and end-systolic pressure as a part of Frank-Starling law is analyzed by means of computer simulation. A hemodynamics...

OBJECTIVE Non-dipper hypertension is associated with an increased cardiovascular morbidity and mortality. Besides this, the left atrial (LA) size and functions are accepted to be prognostic factors in various cardiovascular diseases. In this study, we aimed to evaluate the effect of nondipper hypertension on LA volume and functions using real-time three-dimensional echocardiography (RT3-DE). ...

Abstract Introduction Increased reactive oxygen species are often correlated with erectile dysfunction (ED) by enhancing contractility and favoring the flaccid state of penis (which is mainly mediated α-adrenergic innervation) decreasing relaxation corpus cavernosum (CC) associated decreased nitric oxide (NO) bioavailability. Leucine Rich Repeat Containing 8 (LRRC8) Volume Regulated Anion Chann...