Search results for "nitrate"
showing 10 items of 580 documents
Botulinum toxin vs. topical glyceryl trinitrate ointment for pain control in patients undergoing hemorrhoidectomy: a randomized trial.
2007
PURPOSE: The maximum resting pressure in the anal canal is greatly raised after hemorrhoidectomy. This increase is likely to be the cause of postoperative pain, which is still the most troublesome early problem after hemorrhoidectomy. This study was designed to compare, after hemorrhoidectomy, the effects of intrasphincter injection of botulinum toxin vs. application of glyceryl trinitrate ointment in improving wound heating and reducing postoperative pain at rest or during defecation. METHODS: Thirty patients with hemorrhoids of third and fourth degree were included in the study and randomized in two groups. Anorectal manometry was performed preoperatively and 5 and 40 days after hemorrhoi…
Erythrocyte deformability and nitric oxide metabolites in athletes before and after a cardiopulmonary test.
2009
OBJECTIVE: To evaluate erythrocyte deformability, nitric oxide metabolites, and their modifications induced by exercise in athletes who practised different sports. DESIGN: This evaluation was effected before and after cardiopulmonary test, using a cycloergometer. SETTING: The study was performed in the Department of Internal Medicine, Cardiovascular and Renal Diseases of the University of Palermo. PARTICIPANTS: We enrolled 62 male athletes who practised endurance (n = 23), mixed (n = 20), and power (n = 19) sports and 20 sedentary male subjects as controls. ASSESSMENT OF RISK FACTORS: No subject had diabetes or hypertension or dyslipidemia. Five control subjects and 14 athletes were smokers…
Influence of risk factors on nitric oxide metabolites at the initial stage of juvenile acute myocardial infarction.
2009
Few data are accessible about the nitric oxide (NO) stable end-products (nitrite/NO2 − and nitrate/NO3 − :N O x) in acute coronary syndromes. An increase in inducible NO synthase (iNOS) was found during experimental myocardial infarction [13] and this increase persisted for 2 weeks. In experimental models of acute myocardial infarction (AMI) other authors [2] observed a NOx increase, a correlation between NOx level and iNOS activity and an inhibitory action carried out by S-methylisothiourea, that is an iNOS inhibitor [5]. The NOx level was also measured in a small group of patients with myocardial infarction in whom the peak of NOx elevation occurred 2 and 3 days after the onset of symptom…
Effect of fish oil on LDL oxidation and plasma homocysteine concentrations in health.
2003
Oxidation of low-density lipoprotein (LDL) and hyperhomocysteinemia are believed to play a role in therogenesis. Whether n-3 polyunsaturated fatty acids increase LDL susceptibility to oxidation or influence homocysteine (Hcy) metabolism has long been a subject of controversy. In this study, we evaluated the effect of 8 weeks of dietary supplementation with 6 g/day of fish oil (FO; 3 g of n-3 fatty acids) on plasma lipoproteins, in vitro LDL peroxidation, antioxidant status, and plasma Hcy concentrations in 16 normolipidemic subjects. FO rapidly and significantly (P < .01) decreased plasma total and very low density lipoprotein triglyceride concentrations and had no effect on LDL or high-den…
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…
Comparison of high-pressure liquid chromatography (HPLC) and Griess reagent-spectroscopic methods for the measurement of nitrate in serum from health…
2008
Bioavailability of NO can be estimated by measuring the concentration of nitrate (NO(3)) in serum. However, the methods used for the measurement NO(3) in plasma or serum show a great degree of variation. Therefore, we compared two analytical methods for the measurement of NO(3) in serum.The concentration of NO(3) in 600 serum samples collected from healthy individuals was determined by the HPLC and by the Griess reagent-spectroscopic method.The concentration of NO(3) in the samples was 29.4+/-16.1 micromol/L and 26.2+/-14.0 micromol/L (mean+/-SD) measured by HPLC and Griess reagent-spectroscopic method respectively (p0.0001). We detected a significant correlation between the two methods (R=…
Reply to Castellano and David: Long-term fate of nitrate fertilizer and nitrate from agricultural catchments
2014
We thank Castellano and David for their insightful comments (1) on our paper (2), in which they point out that short-term changes in land use and agricultural management can lead to rapid reductions in nitrate leaching from agricultural systems. We fully agree with Castellano and David that in diversified cropping systems, this N distribution may be different, potentially resulting in reduced nitrate leaching.
Mitochondrial aldehyde dehydrogenase (ALDH-2)--maker of and marker for nitrate tolerance in response to nitroglycerin treatment.
2008
The hemodynamic and anti-ischemic effects of nitroglycerin (GTN) are rapidly blunted as a result of the development of nitrate tolerance. Long-term nitrate treatment also is associated with decreased vascular responsiveness caused by changes in intrinsic mechanisms of the tolerant vasculature itself. According to the oxidative stress concept, increased vascular superoxide and peroxynitrite production as well as an increased sensitivity to vasoconstrictors secondary to activation of protein kinase C as well as vascular NADPH oxidases contribute to the development of tolerance. Recent experimental work has defined new tolerance mechanisms, including inhibition of the enzyme that bioactivates …
Contribution of Bacteria to Initial Input and Cycling of Nitrogen in Soils
2005
Nitrogen was discovered by the Scottish chemist and physician Daniel Rutherford in 1772 by removing oxygen and carbon dioxide from air. At the same time, the French chemist, Antoine Laurent Lavoisier, isolated what we would call nitrogen and named it azote, meaning without life since it did not support life or combustion. However, nitrogen is the fourth most common element in many biomolecules, which are essential for life, being outrankedonly by carbon, hydrogen andoxygen. Thus, nitrogen is found in amino acids that form proteins and in the nucleoside phosphates of nucleic acids. The cycle of nitrogen in soil has been studied more extensively than any other nutrient cycle. Nevertheless, de…
Methods of metal release assessment in soil water at anoxic sites
2006
Department of Geology, Vienna University, Vienna, Austria Metal mobility at contaminated sites can be assessed by soil water investigations or by leaching tests. Leaching tests are usually carried out in open contact with the atmosphere disregarding possible changes of redox conditions. This can affect the original metal speciation and distribution, particularly when anoxic samples are investigated. In this study, the applicability of common leaching tests (the German S4 test (S4), ammonium nitrate extraction (AmmN), and saturation soil extraction (SSE)) is tested for the assessment of zinc release from sulfide-bearing flotation residues of a former ore mine. Results are compared to soil so…