Vascular dysfunction in chronic renal failure may be linked to reduced nitric oxide (NO) bioactivity and increased circulating concentrations of the endogenous NO synthase inhibitor asymmetrical dimethyl L-arginine (ADMA). The association between ADMA and basal endothelial NO release and endothelium-dependent vasodilation in resistance arteries of chronic renal failure patients is unknown. Forearm blood flow responses to the endothelium-dependent vasodilator acetylcholine, the endothelium-independent vasodilator nitroglycerine, and the endothelium-dependent vasoconstrictor N(G)-monomethyl-L-arginine (L-NMMA) were assessed in 37 peritoneal dialysis patients.
View Article and Find Full Text PDFBackground: Beyond lipid lowering, various antiinflammatory properties have been ascribed to statins. Moreover, in vitro studies have suggested the presence of anticoagulant effects of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, as lipopolysaccharide (LPS)-induced monocyte tissue factor (TF) was suppressed. In this study, we examined the role of statins in experimental endotoxemia on inflammatory and procoagulant responses in vivo.
View Article and Find Full Text PDFBackground: Cardiovascular mortality is increased in patients with hypopituitarism. Elevated concentrations of the endogenous NO synthase antagonist asymmetrical dimethylarginine (ADMA) may be related to the development of atherosclerosis and are associated with cardiovascular risk. We studied the concentrations of ADMA in hypopituitary patients with and without growth hormone deficiency (GHD) and in healthy subjects.
View Article and Find Full Text PDFDiabetes Metab
November 2004
Objectives: Plasma malondialdehyde (MDA), a reactive product of lipid peroxidation, may be influenced by anti-oxidant therapy. The aim of the present study was to investigate if elevated MDA as induced by increased free fatty acids (FFA) correlates with endothelial function and is affected by high doses of vitamin C.
Methods: The study design was randomised, placebo-controlled, double blind, 2-way cross over.
Background: Elevated plasma asymmetrical dimethylarginine (ADMA) is suggested to contribute to hyperhomocyst(e)ine-related vascular dysfunction in patients with peripheral artery disease (PAD). The present trial investigated whether homocyst(e)ine (Hcy)-lowering therapy with vitamin-B (vit-B) and folic acid affects plasma concentrations of ADMA in patients with PAD and hyperhomocyst(e)inemia.
Subjects And Methods: Forty-nine subjects (15 women, 34 men) with PAD and fasting plasma total Hcy concentrations greater than 15 micromol/liter were randomized to receive either oral vit-B and folic acid therapy (n = 27) or placebo (n = 22) for 6 wk.
Introduction: Cellular vascular endothelial growth factor (VEGF) expression is increased in response to regional hypoxia, however, contradictory results were reported on the effects of systemic hypoxemia on circulating VEGF levels. This study investigated plasma concentrations of VEGF in patients with a variable degree of overnight hypoxemia due to sleep disordered breathing (SDB).
Methods: VEGF levels were assessed by ELISA in non-activated (VEGFbl) and thrombin stimulated platelet rich plasma (VEGFprp) of 45 patients with SDB: Group 1 patients with obstructive sleep apnea and an apnea-hypopnea index (AHI) > 15/h; Group 2 subjects with an AHI < 5/h; Group 3 patients on CPAP treatment for sleep apnea.
The endogenous nitric oxide-synthase inhibitor asymmetrical dimethyl-L-arginine (ADMA) is elevated in patients with increased risk for arteriosclerosis. Obesity is a risk factor for cardiovascular disease. We measured plasma ADMA concentrations in morbidly obese women before and after weight loss following gastroplastic surgery.
View Article and Find Full Text PDFBackground: There is growing evidence that statins exert anti-inflammatory and antioxidative vascular actions that are independent of lipid lowering. We tested whether hyporeactivity to the endothelium-dependent vasodilator acetylcholine (ACh) and the vasoconstrictor norepinephrine (NE) during acute experimental inflammation could be prevented by simvastatin.
Methods And Results: In a randomized, placebo-controlled, parallel group study, forearm blood flow (FBF) responses to NE, ACh, and the endothelium-independent vasodilator nitroglycerin (NTG) were assessed at baseline, after 4 days of simvastatin 80 mg PO or placebo treatment, and during Escherichia coli endotoxin (lipopolysaccharide [LPS])-induced inflammation in 20 healthy volunteers.
Background: Calcific tendonitis of the shoulder is often associated with chronic pain and impairment of function. Extracorporeal shockwave therapy (ESWT) is considered to be a treatment option. We compared the effects of two different ESWT regimens.
View Article and Find Full Text PDFJ Clin Endocrinol Metab
September 2004
The stomach-derived peptide hormone ghrelin induces appetite and GH release. Several ghrelin actions are possibly mediated and modulated by the central cholinergic system. The aim of this study was to investigate the influence of the unspecific cholinergic antagonist atropine and the acetylcholine esterase inhibitor pyridostigmine, a cholinergic enhancer on ghrelin plasma concentrations and ghrelin-induced GH release.
View Article and Find Full Text PDFBackground: Free fatty acids (FFAs) and triglycerides (TGs) can cause vascular dysfunction and arteriosclerosis. Acute elevation of plasma FFA and TG concentration strongly increase ocular and skin blood flow. This study was designed to discriminate whether FFA or TG independently induce hyperperfusion by measuring regional and systemic haemodynamics.
View Article and Find Full Text PDFPurpose: Short term hyperglycemia has previously been shown to induce a blood flow increase in the retina. The mechanism behind this effect is poorly understood. We set out to investigate whether exercise-induced hyperlactatemia may alter the response of retinal blood flow to hyperglycemia.
View Article and Find Full Text PDFThe objectives were to investigate whether activation of the extrinsic coagulation cascade by recombinant factor VIIa (rFVIIa) reverses the inhibition of thrombin generation and platelet activation by melagatran, the active form of the oral direct thrombin inhibitor ximelagatran. In a single-blind, randomized, parallel-group study, volunteers (20 per group) received a 5-hour intravenous (i.v.
View Article and Find Full Text PDFBackground: Oral administration of ferrous-sulfate was reported to decrease intestinal absorption of mycophenolate mofetil (MMF) in healthy Japanese individuals by 90%.
Methods: We examined the effect of a single oral dose of ferrous sulfate on steady-state mycophenolic acid pharmacokinetics in 10 iron-deficient (hypochromic red blood cells >2.5%), Caucasian, long-term kidney graft recipients using a randomized, open-label, crossover design.
Introduction: Conventional electrical therapies for heart failure (HF) encompass defibrillation and ventricular resynchronization for patients at high risk for lethal arrhythmias and/or with inhomogeneous ventricular contraction. Cardiac contractility modulation (CCM) by means of nonexcitatory electrical currents delivered during the action potential plateau has been shown to acutely enhance systolic function in humans with HF. The aim of this multicenter study was to assess the chronic safety and preliminary efficacy of an implantable device delivering this novel form of electrical therapy.
View Article and Find Full Text PDFAim: In experimental studies, nonexcitatory electrical stimulation delivered at the time of absolute myocardial refractoriness resulted in cardiac contractility modulation (CCM) with improved systolic function. This study reports the initial experience with CCM in patients with chronic heart failure.
Methods And Results: Twenty-five patients, 23 males, with a mean age of 62+/-9 years and drug-refractory NYHA class III heart failure were assigned to CCM-generator implantation.
Introduction: The effect of the oral direct thrombin inhibitor (DTI) ximelagatran (Exanta, AstraZeneca) on the endogenous thrombin potential (ETP) of activated plasma was investigated ex vivo using a thrombin generation assay and compared with recombinant (r)-hirudin and enoxaparin.
Materials And Methods: 120 healthy male volunteers were randomized to one of six treatment groups (n=20 in each): oral ximelagatran (15, 30, or 60 mg), intravenous r-hirudin (0.4 mg/kg bolus, 0.
Exercise is a potent, dose-dependent stimulus of growth hormone (GH) secretion. The hypothalamic peptides, GH-releasing hormone (GHRH) and somatostatin are regarded as major regulators of this stimulation. The role of the stomach-derived peptide ghrelin, which has been shown to exert strong GH releasing effects, has not been fully characterized yet.
View Article and Find Full Text PDFAm J Physiol Heart Circ Physiol
August 2004
Administration of low doses of Escherichia coli endotoxin [a lipopolysaccharide (LPS)] to humans enables the study of inflammatory mechanisms. The purpose of the present study was to investigate whether the blue-field entoptic technique may be used to quantify the increase in circulating leukocytes in the ocular microvasculature after LPS infusion. In addition, combined laser Doppler velocimetry and retinal vessel size measurement were used to study red blood cell movement.
View Article and Find Full Text PDFThere is evidence that hyperinsulinemia may stimulate endothelin-1 (ET-1) generation or release, which may affect diabetic vascular complications. BQ-123, a specific ET(A) receptor antagonist, was used to investigate if insulin-induced vascular effects are influenced by an acute ET-1 release. Two randomized, placebo-controlled, double-blind, cross-over studies were performed.
View Article and Find Full Text PDFAcute inflammation impairs vascular function. Based on the association between endothelial dysfunction and plasma concentrations of L-arginine and the endogenous nitric oxide synthase inhibitor ADMA (asymmetrical dimethylarginine), we hypothesized that the ratio between L-arginine and ADMA could be affected by experimental inflammation. Plasma concentrations of L-arginine, ADMA and SDMA (symmetrical dimethylarginine) were studied at baseline and 3.
View Article and Find Full Text PDFNeuromuscular electrical stimulation (NMES) is an option for increasing thigh muscle strength and endurance capacity in patients with chronic heart failure. Electromagnetic interference (EMI) by the signals with sensing of implantable cardioverter defibrillators (ICDs) is possible. The aim of the present pilot safety study was to test the safety of a long-term NMES in patients with ICDs.
View Article and Find Full Text PDFNeuromuscular electrical stimulation (NMES) is an effective and non-strenuous therapy to enhance the strength and endurance capacity of the skeletal muscles in patients with severe chronic heart failure. NMES in patients with pacemakers is controversial because potential electromagnetic interference may result in pacemaker malfunction. Therefore, such patients are in general excluded from NMES.
View Article and Find Full Text PDFThis study investigated the pharmacodynamic effects of the oral direct thrombin inhibitor ximelagatran on platelet activation and thrombin generation in patients with nonvalvular atrial fibrillation. Using an open, group-matched study design, the effects of ximelagatran (36 mg twice daily for 5 days) were studied in 12 patients with permanent nonvalvular atrial fibrillation and in 12 healthy controls. After ximelagatran for 5 days, elevated platelet P-selectin expression in atrial fibrillation patients was lowered to that during coumarin treatment or in controls but had no effect in control subjects.
View Article and Find Full Text PDFObjectives: We sought to determine the role of oxidative stress in the development of vascular dysfunction in inflammation.
Background: Hyporeactivity to catecholamines and other vasoconstrictors is present in acute inflammation. Because oxidative stress plays a significant role in inflammation, impaired responsiveness may be overcome by anti-oxidants.