Search results for "Arginine"
showing 10 items of 389 documents
Plasma levels of atrial natriuretic peptide and hemodynamic function in cardiac disease.
1993
Plasma concentrations of atrial natriuretic peptide were measured in eight patients with cardiac disease but normal resting right atrial pressure, during cardiac catheterization. No patient had clinical evidence of overt heart failure. An increase in peptide concentrations was observed between the aorta or the peripheral vein and the pulmonary artery. A linear relation was found between peripheral vein and pulmonary artery peptide concentration. Mean pulmonary artery and capillary wedge pressure also correlated with the peptide levels. No correlation was observed between mean right atrial pressure and peptide concentration. These findings demonstrate that atrial natriuretic peptide release,…
Differential Effects of Dry Eye Disorders on Metabolomic Profile by 1H Nuclear Magnetic Resonance Spectroscopy
2014
We used1H NMR spectroscopy to analyze the metabolomic profile of reflex tears from patients with dry eye disorders (DEDs). 90 subjects were divided into 2 groups: (1) patients with DEDs (DEDG;n = 55) and (2) healthy subjects (CG;n = 35). Additionally, the DEDG was subdivided into 2 subgroups based on DED severity: mild-to-moderate and moderate (n = 22andn = 33, resp.). Personal interviews and systematized ophthalmologic examinations were carried out. Reflex tears (20–30 μL) were collected by gently rubbing in the inferior meniscus of both eyelids with a microglass pipette and stored at −80°C until analysis. NMR spectra were acquired using a standard one-dimensional pulse sequence with water…
Desmopresssin and hemodilution: implications in doping.
2009
Blood doping improves physical performance in sport. This is the reason why the antidop- ing authorities subject athletes to blood tests. Plasma volume expanders are prohibited agents used to reduce an artifi cial increase in hemato- logical values using diff erent illegal practices. The aim of our study was to test whether desmo- pressin (DDAVP)-induced hemodilution would alter the concentration of hematological param- eters used to detect blood doping in sports. This was an intra-subject crossover study. Venous blood samples were obtained from eight physi- cally active males on two occasions. On the fi rst o ccasion the subjects ingested 1.5 L of mineral water and 4.3 μ g / kg of DDAVP. O…
Asymmetric Dimethylarginine and the Risk of Cardiovascular Events and Death in Patients With Coronary Artery Disease
2005
As a competitive inhibitor of endothelial nitric oxide synthase, asymmetric dimethylarginine (ADMA) has been related to atherosclerotic disease. Little is known about the prognostic impact of baseline ADMA determination. In a prospective cohort of 1908 patients with coronary artery disease, we assessed baseline serum concentration of ADMA in 1874 consecutive patients with coronary artery disease. One hundred fourteen individuals developed the primary end point of death from cardiovascular causes or nonfatal myocardial infarction during a mean follow-up of 2.6±1.2 years. Median concentrations of ADMA levels were higher among individuals who subsequently developed the primary end point than …
ADMA, subclinical changes and atrial fibrillation in the general population.
2015
Abstract Background Pathways of oxidative stress, nitric oxide bioavailability and l-arginine derivatives are hypothesized to be related to atrial fibrillation (AF). Circulating methylated l-arginine metabolites can be assessed in the general population and may show an association with AF. Methods We determined l-arginine and its metabolites asymmetric dimethylarginine (ADMA), l-N ω -monomethylarginine (NMMA) and symmetric dimethylarginine (SDMA) in the population-based Gutenberg Health Study (n=5000), mean age 55±11years, 51% men, in association with clinical variables of AF such as electrocardiographic and echocardiographic measures and manifest AF. Results Individuals with AF (N=161), 71…
Nitric oxide mediates abnormal responsiveness of thyroid arteries in methimazole-treated patients.
2005
Objective: We studied the intervention of nitric oxide (NO), prostacyclin and endothelium-derived hyperpolarizing factor (EDHF) in mediating responses to acetylcholine in thyroid arteries from euthyroid and methimazole-treated (MT) patients. Design and methods: Branches of the superior thyroid artery were obtained from 19 euthyroid patients and 17 MT patients (euthyroid at the time of surgery) undergoing total thyroidectomy or hemithyroidectomy. Artery rings were suspended in organ baths for isometric recording of tension. Results and conclusions: Acetylcholine caused endothelium-dependent relaxation of greater magnitude in arteries from MT patients (pD2 (−log EC50) values were 7.68±0.19 in…
Influence of Endothelial Nitric Oxide on Adrenergic Contractile Responses of Human Cerebral Arteries
1996
The present study was designed to investigate the influence of the endothelium and that of the L-arginine pathway on the contractile responses of isolated human cerebral arteries to electrical field stimulation (EFS) and norepinephrine. Rings of human middle cerebral artery were obtained during autopsy of 19 patients who had died 3–8 h before. EFS (1–8 Hz) induced frequency-dependent contractions that were abolished by tetrodotoxin, prazosin, and guanethidine (all at 10-6 M). The increases in tension were of greater magnitude in arteries denuded of endothelium. NG-monomethyl L-arginine (L-NMMA 10-4 M) potentiated the contractile response to EFS in artery rings with endothelium but did not …
Enhancement by vasopressin of adrenergic responses in human mesenteric arteries.
1997
Vasopressin not only acts directly on blood vessels through V1-receptor stimulation but also may modulate adrenergic-mediated responses in animal experiments in vitro and in vivo. The aim of the present study was to investigate whether subpressor concentrations of vasopressin could modify the constrictor responses to norepinephrine and electrical stimulation of the perivascular nerves in human mesenteric arteries. Human mesenteric artery rings (3-3.5 mm long, 0.8-1.2 mm OD) were obtained from 38 patients undergoing abdominal operations. The arterial rings were suspended in organ bath chambers for isometric recording of tension. Vasopressin (3 x 10(-11) M) enhanced the contractions elicited…
Plasma concentration of asymmetric dimethylarginine, an endogenous inhibitor of nitric oxide synthase, is elevated in hyperthyroid patients.
2002
Cardiovascular manifestations are frequent findings in patients with thyroid hormone disorders. Nitric oxide (NO) plays a key role in vascular, endothelial-mediated relaxation. NO is synthesized from L-arginine by NO synthase, an enzyme inhibited by endogenous compounds, mainly asymmetric dimethylarginine [asymmetric N(G),N(G)-dimethyl-L-arginine (ADMA)]. The aim of our work was to investigate whether plasma L-arginine and dimethylarginine concentrations and NO production are altered in hypo- and hyperthyroid patients, compared with control subjects. L-arginine, ADMA and symmetric dimethylarginine were analyzed by HPLC. NO was measured as plasma nitrite plus nitrate (NO(x)) concentration by…
Estradiol counteracts oxidized LDL-induced asymmetric dimethylarginine production by cultured human endothelial cells.
2006
Objective: Asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide (NO) synthase, is a novel cardiovascular risk factor produced by endothelial cells. ADMA levels are mainly regulated by the activity of dimethylarginine dimethylaminohydrolases (DDAH). Endothelial release of ADMA is increased in the presence of oxidized LDL cholesterol (oxLDL), whereas estrogens stimulate NO production by endothelial cells by increasing both expression and activity of NO synthase and by reducing ADMA levels. Thus, the aim of the present study was to evaluate the estradiol effects on the DDAH/ADMA/NO pathway in cultured human umbilical vein endothelial cells (HUVEC) exposed to LDL. Methods…