Resting microvascular resistance and conduit artery tone: relevance to endothelium-dependent flow-mediated dilation.

Background: Conduit arteries respond to increases in flow by dilating, which is mediated by endothelium-derived nitric oxide. The significance of the interaction between microcirculation and macrocirculation in the flow-mediated dilation (FMD) is poorly understood.

Hypothesis: We hypothesize that baseline conduit artery vasomotor tone (CAVT) and resting microvascular resistance (MVR) predict FMD.

"One-stop-shop" ultrasound diagnosis of functional, structural and physicomechanical properties of the brachial artery.

Background: The pathogenesis of atherosclerosis comprises endothelial dysfunction, thickening as well as impaired compliance of the arterial vessel wall. Early assessment of these alterations of the vessel wall at the same site of the vascular tree has yet been hampered by the lack of highly sensitive diagnostic approaches suitable for clinical routine. We therefore aimed to develop and validate a single non-invasive examination of the brachial artery for simultaneous and highly accurate measurement of functional, structural and physicomechanical parameters of the brachial artery.

Contraceptive efficacy, compliance and beyond: factors related to satisfaction with once-weekly transdermal compared with oral contraception.

Objective: To investigate contraceptive efficacy, compliance and user's satisfaction with transdermal versus oral contraception (OC).

Study Design: Randomized, open-label, parallel-group trial conducted at 65 centers in Europe and South Africa. One thousand four hundred and eighty-nine women received a contraceptive patch (n = 846) or an OC (n = 643) for 6 or 13 cycles.

Reduction of peripheral flow reserve impairs endothelial function in conduit arteries of patients with essential hypertension.

Background: A diminished flow reserve in resistance vessels is a hallmark of hypertensive microvascular disease. Hypertension is associated with structural alterations in the microcirculation and a reduced endothelium-dependent dilation in conduit arteries. Both have been demonstrated to predict future cardiovascular events.

Effect of controlled-release delivery on the pharmacokinetics of oxybutynin at different dosages: severity-dependent treatment of the overactive bladder.

Objective: To assess the pharmacokinetics of a controlled-release formulation of oxybutynin (OROS-O, ALZA Corp., Mountain View, CA) at different dosages, compared with immediate-release oxybutynin (IR-O), and to determine the pharmacodynamic properties in the severity-dependent reduction of urge urinary incontinence (UUI).

Patients And Methods: In all, 105 patients were enrolled in this multicentre, randomized, double-blind study.

Management of the hypertensive patient with coronary insufficiency but without atherosclerosis.

Arterial hypertension is a major risk factor for the clinical syndrome of angina pectoris, in which the ECG is abnormal but the coronary arteries are normal. Structural and functional abnormalities in coronary circulation as well as extravascular factors (eg, left-ventricular hypertrophy, fibrosis with diastolic dysfunction) compromise the adequate ratio of coronary blood flow to oxygen demand causing angina, dyspnea, and major cardiac events. Recent studies stress the importance to functional disturbances of coronary microvasculature leading to profound morphologic changes associated with impaired coronary conductance.

Effects of right coronary artery PTCA on variables of P-wave signal averaged electrocardiogram.

Background: P-wave signal averaged ECG has been used to detect atrial late potentials that were found in paroxysmal atrial fibrillation. Ischemia is supposed to trigger ventricular late potentials, which indicate an elevated risk for ventricular tachycardia. Preexistent ventricular late potentials measured by ventricular signal averaged ECG is supposed to be eliminated by successful PTCA.

Direct biochemical evidence for eNOS stimulation by bradykinin in the human forearm vasculature.

Objective: Although it has been shown recently that acetylcholine (ACh)-induced vasodilation of forearm resistance vessels is predominantly mediated by nitric oxide, direct biochemical evidence for eNOS stimulation by bradykinin (BK) in the human arterial circulation is still lacking. Therefore, the present study was designed to test the hypothesis that in the human forearm vasculature eNOS stimulation significantly contributes to BK-induced vasodilation.

Methods: BK was infused in the presence and absence of the NOS inhibitor L-NMMA (8 micromol/min) into the brachial artery of 16 healthy volunteers and the effects compared to muscarinergic eNOS stimulation following acetylcholine infusion.

Plasma nitrosothiols contribute to the systemic vasodilator effects of intravenously applied NO: experimental and clinical Study on the fate of NO in human blood.

Higher doses of inhaled NO exert effects beyond the pulmonary circulation. How such extrapulmonary effects can be reconciled with the presumed short half-life of NO in the blood is unclear. Whereas erythrocytes have been suggested to participate in NO transport, the exact role of plasma in NO delivery in humans is not clear.

Evidence for in vivo transport of bioactive nitric oxide in human plasma.

Although hitherto considered as a strictly locally acting vasodilator, results from recent clinical studies with inhaled nitric oxide (NO) indicate that NO can exert effects beyond the pulmonary circulation. We therefore sought to investigate potential remote vascular effects of intra-arterially applied aqueous NO solution and to identify the mechanisms involved. On bolus application of NO into the brachial artery of 32 healthy volunteers, both diameter of the downstream radial artery and forearm blood flow increased in a dose-dependent manner.

[Recurrent epistaxis in a patient with aortic valve stenosis: a variant of Heyde syndrome?].

Background: The Heyde syndrome describes the coincidence of aortic valve stenosis and intestinal bleeding. The pathophysiologic link between both entities has remained unclear so far. In several studies the intestinal bleedings have been attributed to angiodysplasia.

Plasma nitrite rather than nitrate reflects regional endothelial nitric oxide synthase activity but lacks intrinsic vasodilator action.

The plasma level of NO(x), i.e., the sum of NO(2)- and NO(3)-, is frequently used to assess NO bioavailability in vivo.

Automated ultrasonic measurement of human arteries for the determination of endothelial function.

Aim: Brachial artery ultrasonography is used to measure flow-mediated dilatation (FMD) as a marker of endothelial function in patients at risk for atherosclerosis. Major disadvantages are the time-consuming manual readings and the high within- and between-observer variability. The authors hypothesize that the ultrasound-based determination of endothelial function can be simplified and refined by an automated analysis system.

Additive effect of coexistent type 2 diabetes and arterial hypertension on endothelial dysfunction in resistance arteries of human forearm vasculature.

Population studies suggest that vascular complications accumulate when arterial hypertension supervenes on diabetes mellitus. Although it has been demonstrated that endothelial function is impaired in patients with either diabetes mellitus or arterial hypertension it is unknown whether or not both diseases exert additive effects on endothelial dysfunction. The authors therefore investigated endothelium-dependent and endothelium-independent vasodilation in the forearm vasculature of 44 individuals: in 10 type 2 diabetic patients (DM), in 12 patients with arterial hypertension (HT), in 10 patients with both DM and HT (DM+HT), and in 12 healthy control subjects (C).

Serum nitrite sensitively reflects endothelial NO formation in human forearm vasculature: evidence for biochemical assessment of the endothelial L-arginine-NO pathway.

Objective: A reduced bioactivity of endothelial nitric oxide (NO) has been implicated in the pathogenesis of atherosclerosis. In humans, the endothelial L-arginine-NO pathway has been indirectly assessed via the flow response to endothelium-dependent vasodilators locally administered into the coronary, pulmonary or forearm circulation. However, biochemical quantification of endothelial NO formation in these organ circulations has been hampered so far because of the rapid metabolism of NO.

Impairment of adenosine-induced dilation of forearm resistance arteries in patients with arterial hypertension.

Background: Adenosine is a potent mediator of arteriolar tone in particular during ischemia, hypoxia, and exercise. Functional disturbance of this dilatory pathway may be highly significant for the pathophysiology and pathogenesis of arterial hypertension.

Patients And Methods: Forearm blood flow (FBF) was quantified by venous occlusion plethysmography following intra-arterial infusion of adenosine at increasing doses in 13 patients with arterial hypertension (HT) and 12 age-matched normotensive controls (NT).

[Coronary vasomotion in coronary heart disease--significance of epicardial and microcirculatory vessels for myocardial perfusion].

The most important function of the coronary vasculature is the effective regulation of coronary blood flow according to the metabolic needs of the myocardium. Under physiological conditions, coronary blood flow is regulated by a balance of vasoconstricting and -dilating components which can be differentiated with regard to the site (macro- vs. microcirculation), compartment (endothelium vs.

Selective impairment of nitric oxide dependent vasodilation in young adults with hypercholesterolaemia.

Objective: To investigate comparatively flow response of resistance arteries to exogenous and endogenous nitric oxide in young adults with high serum cholesterol.

Background: Impaired vascular effectiveness of endogenous and exogenous nitric oxide may be considered to unmask impairment of its anti-atherogenic properties. It may thus represent a valuable early diagnostic index for these young adults at high risk for developing atherosclerosis.

Impaired effectiveness of nitric oxide-donors in resistance arteries of patients with arterial hypertension.

Objective: To assess the dilatory effectiveness of nitric oxide donors in resistance arteries of patients with arterial hypertension in comparison with that in those of normotensive controls.

Background: Endothelium-dependent vasodilation has been demonstrated to be impaired in arterial hypertension. Besides disturbances in endothelial nitric oxide production a reduced vasodilatory effectiveness of nitric oxide might contribute to this phenomenon of endothelial dysfunction.

Evidence for a multifactorial process involved in the impaired flow response to nitric oxide in hypertensive patients with endothelial dysfunction.

The assessment of endothelial function in hypertensive patients receiving acetylcholine has revealed conflicting results. Whether an impaired flow response to acetylcholine is explained solely by a diminished endothelial synthesis of nitric oxide (NO) remains unclear as yet. In the present study, we tested the hypothesis that mechanisms other than reduced NO synthesis contribute to the hypertension-associated impairment of endothelium-dependent vasodilation.