Umbilical artery Doppler velocimetry waveform notching has long been associated with umbilical cord abnormalities, such as distortion, torsion, and/or compression (i.e., constriction). The physical mechanism by which the notching occurs has not been elucidated. Flow velocity waveforms (FVWs) from two-dimensional pulsatile flows in a constricted channel approximating a compressed umbilical cord ...

Studies were performed on anesthetized saline-loaded dogs to delineate the factors involved in the antinatriuretic effect of acute constriction of the thoracic (TIVC) and abdominal (AIVC) inferior vena cava. Acute TIVC constriction lowered cardiac output and arterial blood pressure and reduced urinary sodium excretion 48%; the same degree of reduction in renal perfusion pressure by suprarenal a...

Studies were performed on anesthetized saline-loaded dogs to delineate the factors involved in the antinatriuretic effect of acute constriction of the thoracic (TIVC) and abdominal (AIVC) inferior vena cava. Acute TIVC constriction lowered cardiac output and arterial blood pressure and reduced urinary sodium excretion 48%; the same degree of reduction in renal perfusion pressure by suprarenal a...

Estrogen regulation of myocardial chymase and chymase effects on cardiac remodeling are unknown. To test the hypothesis that estrogen prevents pressure overload-induced adverse cardiac remodeling by inhibiting mast cell (MC) chymase release, transverse aortic constriction or sham surgery was performed in 7-week-old intact and ovariectomized (OVX) rats. Three days before creating the constrictio...

Tosun M, Erac Y, Selli C, Karakaya N. Sarcoplasmic-endoplasmic reticulum Ca -ATPase inhibition prevents endothelin A receptor antagonism in rat aorta. Am J Physiol Heart Circ Physiol 292: H1961–H1966, 2007. First published December 15, 2006; doi:10.1152/ajpheart.00298.2006.—This study tested whether sarcoplasmic-endoplasmic reticulum Ca -ATPase regulates the ability of endothelin receptor antag...

Graphene kinks are topological states of buckled graphene membranes. We show that when a moving kink encounters constriction, there three general classes behavior: reflection, trapping, and transmission. Overall, constriction is characterized by an attractive potential. In the case simple symmetric potential energy has relatively deep minimum surrounded barriers. However, alone does not fully d...

In hypertension, pressure-induced myogenic constriction and impaired endothelium-derived hyperpolarizing factor (EDHF)-mediated dilation may contribute to increased vasomotor tone. Myogenic constriction as well as EDHF-mediated dilation may share common signaling mechanisms, and both may control KCa channel activity to set arterial tone. To investigate a potential relation between the 2 mechani...

This study tested whether sarcoplasmic-endoplasmic reticulum Ca(2+)-ATPase regulates the ability of endothelin receptor antagonist to inhibit the endothelin-1 constriction. The endothelin A receptor antagonist BQ-123 (1 microM) completely relaxed constriction to 10 nM endothelin-1 in endothelium-denuded rat aorta. Challenge with cyclopiazonic acid (10 microM), a sarcoplasmic-endoplasmic reticul...