The fetal llama responds to hypoxemia, with a marked peripheral vasoconstriction but, unlike the sheep, with little or no increase in cerebral blood flow. We tested the hypothesis that the role of nitric oxide (NO) may be increased during hypoxemia in this species, to counterbalance a strong vasoconstrictor effect. Ten fetal llamas were operated under general anesthesia. Mean arterial pressure ...

PURPOSE Patients with diastolic dysfunction may have a disproportionate degree of elevation in pulmonary pressure, particularly in the elderly. Higher pulmonary vascular resistance in the elderly patients with heart failure but preserved ejection fraction suggests that beyond the post-capillary contribution of pulmonary venous congestion, a pre-capillary component of pulmonary arterial hyperten...

BACKGROUND Heart failure (HF) is frequently associated with dysregulation of nitric oxide-mediated pulmonary vascular tone. Sildenafil, a type 5 phosphodiesterase inhibitor, lowers pulmonary vascular resistance in pulmonary hypertension by augmenting intracellular levels of the nitric oxide second messenger, cyclic GMP. We tested the hypothesis that a single oral dose of sildenafil (50 mg) woul...

Cardiac tamponade is associated with decreased cardiac output and increased systemic vascular resistance. Thus, vasodilator drugs might lower systemic resistance and increase cardiac output. Three groups of dogs were studied during tamponade. Group I received nitroprusside only; group II received blood transfusion and then nitroprusside; group III received hydralazine. In group I, nitroprusside...

OBJECTIVE To assess whether changes in Doppler echocardiographic indices in the pulmonary artery correlated with changes in pulmonary vascular resistance. DESIGN Acceleration time, ejection time, maximal flow velocity, and velocity time integrals were measured at the same time as pressure and oxygen saturation measurements in room air and during 10 minutes of oxygen breathing in the catheteri...

OBJECTIVE The state of pulmonary vascular bed in congenital heart disease is the predictor of the patients clinical condition, prognosis and outcome of surgical intervention. This study aims to investigate the condition of pulmonary vascular bed analyzing pulmonary artery stiffness by means of Doppler echocardiography. METHODS Thirty-three patients (16 females, mean age 26+/-15 years) with va...

To explore the contribution of red blood cell (RBC) deformability and interaction with endothelial cells (ECs) to circulatory disorders, these RBC properties were modified by treatment with hydrogen peroxide (H(2)O(2)), and their effects on vascular resistance were monitored following their infusion into rat mesocecum vasculature. Treatment with 0.5 mM H(2)O(2) increased RBC/EC adherence withou...

BACKGROUND Suboptimal fetal nutrition may influence early growth and cardiovascular development. We examined whether umbilical and uterine artery resistance indices, as measures of feto-placental and utero-placental vascular function, respectively, are associated with fetal and childhood growth and cardiovascular development. METHODS AND RESULTS This study was embedded in a population-based p...

Vascular insulin resistance contributes to elevated peripheral vascular resistance and subsequent hypertension. Clinical observation showed that lower plasma adiponectin concentration is significantly associated with hypertension. This study was aimed to determine whether hypoadiponectinemia induces vascular insulin resistance before systemic hypertension and the underlying mechanisms. Four-wee...

BACKGROUND The endothelium synthesizes and releases a relaxing factor with the physiochemical properties of nitric oxide (NO). However, the role of endothelium-derived NO in the basal regulation of systemic and pulmonary vascular resistance in humans is not known. Our primary objectives were to determine the effects of inhibiting NO synthesis on blood pressure and systemic vascular resistance a...