Volatile anaesthetics inhibit endothelium-dependent relaxation, but the underlying mechanism(s) have not been clarified. In an attempt to elucidate the mechanism(s), we determined the effects of halothane, isoflurane and sevoflurane on relaxation induced by acetylcholine and sodium nitroprusside (SNP) and the cGMP formation elicited by exogenous nitric oxide (NO) and SNP in rat aortas. Acetylch...

PTHrP has important roles in lung development and function. Here we determined the vasomotor responses of isolated pulmonary arteries and veins of newborn and adult sheep to PTHrP. In vessels constricted with endothelin-1, PTHrP (PTHrP 1-34) caused greater relaxation of veins than of arteries. In both vessel types, relaxation to the peptide was less in adult than in newborn vessels. In newborn ...

Endothelium-derived relaxing factors may differentially modulate vascular tone and relaxation in arteries from specific vascular beds. We evaluated the role of nitric oxide (NO), prostacyclin (PGI2) and endothelium-derived hyperpolarizing factor in determining basal tone and acetylcholine (ACh)-induced relaxation of coronary (Cor), skeletal muscle (Ske) and mesenteric (Mes) small arteries (150-...

Under normoxic conditions in vitro, isolated pulmonary arteries from broilers exhibit reduced endothelium-dependent relaxation responses when compared with Leghorns. In vivo, hypoxia increases the susceptibility of broiler chickens to pulmonary hypertension syndrome (PHS), whereas Leghorns are considered resistant to PHS. Because L-arginine supplementation decreases the incidence of PHS in vivo...

The water swelling and drug diffusion from initially hydrophilic, glassy polymer matrices were modeled using concentration-dependent diffusion equations for water and drug. The transport equation for water incorporated a relaxation-dependent mechanism. These equations were solved with an appropriate boundary condition incorporating a relaxation-dependent Deborah number. Experimental results fro...

The reduction in estrogen in postmenopausal women contributes to an increase in vascular dysfunction. Models of aging have shown that this is due, in part, to increased prostaglandin H synthase (PGHS)-dependent vasoconstriction. We showed previously that inducible PGHS-2-dependent vasoconstriction is increased with aging. In the present study, we hypothesized that estrogen suppresses PGHS-2-dep...

The purpose of this paper is to analysis the viscoelastic models under dynamic loading. A five-parameter model is chosen for study exhibits elastic, viscous, and retarded elastic response to shearing stress. The viscoelastic specimen is chosen which closely approximates the actual behavior of a polymer. The module of elasticity and viscosity coefficients are assumed to be space dependent i.e. f...

The biochemical mechanism of action of synthetic atrial natriuretic factor (atriopeptin II) was studied in vascular smooth muscle of the rabbit thoracic aorta. Atriopeptin II caused a time-dependent and concentration-dependent increase in tissue levels of cyclic guanosine monophosphate that corresponded in these same tissues with vascular relaxation. The elevation of arterial cyclic guanosine m...

Accurate joint models require the ability to predict soft tissue behavior. This study evaluates the ability of constitutive equations to predict the nonlinear and viscoelastic behavior of tendon and ligament during stress relaxation testing in a porcine model. Three constitutive equations are compared in their ability to model relaxation, recovery and reloading of tissues. Quasi-linear viscoela...

Temperature and carrier density-dependent spin dynamics for GaAs/AlGaAs quantum wells (QWs) with different structural symmetries have been studied by using time-resolved Kerr rotation technique. The spin relaxation time is measured to be much longer for the symmetrically designed GaAs QW comparing with the asymmetrical one, indicating the strong influence of Rashba spin-orbit coupling on spin r...