Search results for "Peroxynitrous Acid"
showing 10 items of 23 documents
Conversion of biliverdin to bilirubin by biliverdin reductase contributes to endothelial cell protection by heme oxygenase-1—evidence for direct and …
2009
Heme oxygenase-1 (HO-1) is highly protective in various pathophysiological states such as cardiovascular and neurodegenerative diseases. HO-1-derived bilirubin is an efficient scavenger of reactive oxygen and nitrogen species (RONS). It remains to determine whether conversion of biliverdin to bilirubin is an essential step for HO-1-conferred protection of endothelial cells. RONS scavenging activities of biliverdin versus bilirubin were assessed by different RONS generating systems and detection techniques. We also silenced the biliverdin reductase (BVR) or HO-1 gene in cultured primary human endothelial cells (HUVECs) and measured the effect on RONS formation upon stimulation with lipopolys…
Cirrhotic patients with minimal hepatic encephalopathy have increased capacity to eliminate superoxide and peroxynitrite in lymphocytes, associated w…
2018
Patients with minimal hepatic encephalopathy (MHE) show increased oxidative stress in blood. We aimed to assess whether MHE patients show alterations in different types of blood cells in (a) basal reactive oxygen and nitrogen species levels; (b) capacity to metabolise these species. To assess the mechanisms involved in the altered capacity to metabolise these species we also analysed: (c) peroxynitrite formation and d) peroxynitrite reaction with biological molecules. Levels of reactive oxygen and nitrogen species were measured by flow cytometry in blood cell populations from cirrhotic patients with and without MHE and controls, under basal conditions and after adding generators of superoxi…
Low SOD activity is associated with overproduction of peroxynitrite and nitric oxide in patients with acute coronary syndrome
2015
Abstract Objective The present study was undertaken to evaluate the variation of the oxidative/nitrosative stress status in a population of subjects; with acute coronary syndrome (ACS), and examine its possible implication in plaque rupture which is the main mechanism in the pathophysiology of ACS. Patients and methods We made this study on 50 men with ACS and 50 age and sex matched healthy controls. Nitrosative/oxidative stress markers including; nitric oxide, superoxide anion levels, superoxide dismutase (SOD) activity and peroxynitrite levels were evaluated in blood samples of patients and controls. Results Compared with healthy subjects, coronary patients had significantly higher nitric…
Increased Circulating Levels of 3-Nitrotyrosine Autoantibodies
2012
3-nitrotyrosine formation is an oxidative protein modification that was first discovered in vivo in the early 1990s by Beckman and colleagues.1,2 The biological relevance of this process was extensively investigated in the subsequent years and further facilitated by the development of 3-nitrotyrosine–specific antibodies.3 Protein tyrosine nitration is mainly mediated by 3 biochemical processes (Figure): (1) by peroxynitrite (ONOO−) formation,4–6 the reaction product of nitric oxide (•NO) and superoxide (•O2−); (2) by a (myelo)peroxidase-catalyzed nitrogen dioxide radical (•NO2) formation from hydrogen peroxide and nitrite;7,8 and (3) by a nonspecific formation of the nitrogen dioxide radica…
The effects of nitric oxide on striatal serotoninergic transmission involve multiple targets: an in vivo microdialysis study in the awake rat
2004
Abstract The role of endogenous nitric oxide (NO) in N -methyl- d -aspartate (NMDA)-induced modulation of serotonin (5-HT) release in the striatum of freely moving rats has been studied using microdialysis technique. NMDA-induced increase in 5-HT release was significantly inhibited by selective nitric oxide synthase (nNOS) inhibitor S -methylthiocitrulline (S-Me-TC), ONOO − scavenger l -cysteine ( l -cys), and guanylate cyclase (GC) inhibitor 1 H [1,2,4]oxadiazolo[4,3- a ]quinoxalin-1-one (ODQ). These data suggest that modulation of 5-HT levels is linked to the formation of NO produced by NMDA receptor activation and that endogenously produced NO increases 5-HT concentrations both by stimul…
Sex-dependent changes in the pulmonary vasoconstriction potential of newborn rats following short-term oxygen exposure
2012
Chronic exposure to supplemental oxygen (O(2)) induces lung damage and mortality in a sex-dependent manner. The effect of short-term hyperoxia on the newborn pulmonary vasculature is unknown but is, however, of clinical significance in the neonatal resuscitation context. We hypothesize that short-term hyperoxia has a sex-dependent effect on the pulmonary vasculature.Following 1-h 100% O(2) exposure, the pulmonary arteries and lung tissues of newborn rats were evaluated.Superoxide dismutase 3 (SOD3) expression in female pups' lungs was increased as compared with that in the lungs of male pups. As compared with air-treated pups, the response of male pups to thromboxane was increased by O(2), …
Hydralazine is a powerful inhibitor of peroxynitrite formation as a possible explanation for its beneficial effects on prognosis in patients with con…
2005
The hemodynamic and anti-ischemic effects of nitroglycerin (GTN) are rapidly blunted as a result of the development of nitrate tolerance. Hydralazine has been shown to prevent tolerance in experimental and clinical studies, all of which may be at least in part secondary to antioxidant properties of this compound. The antioxidant effects of hydralazine were tested in cell free systems, cultured smooth muscle cells, isolated mitochondria, and isolated vessels. Inhibitory effects on the formation of superoxide and/or peroxynitrite formation were tested using lucigenin and L-012 enhanced chemiluminescence as well as DHE-fluorescence. The peroxynitrite scavenging properties were also assessed by…
Phenylpropanoid and phenylisoprenoid metabolites from Asteraceae species as inhibitors of protein carbonylation.
2011
Abstract Three phenolic antioxidant and anti-inflammatory compounds: 7-methylaromadendrin, isoprenylhydroquinone glucoside, and 3.5-dicaffeoylquinic acid methyl ester, all isolated from Western Mediterranean Asteraceae species, have been studied for their inhibitory activity against protein carbonylation, a harmful post-translational modification of peptide chains associated with degenerative diseases. All compounds have proven to be effective, with 50% inhibitory concentration (IC 50 ) values in the micromolar range, against bovine serum albumin carbonylation caused by hypochlorite, peroxynitrite, and phorbol ester-induced leukocyte oxidative burst.
Explaining the phenomenon of nitrate tolerance.
2005
During the last century, nitroglycerin has been the most commonly used antiischemic and antianginal agent. Unfortunately, after continuous application, its therapeutic efficacy rapidly vanishes. Neurohormonal activation of vasoconstrictor signals and intravascular volume expansion constitute early counter-regulatory responses (pseudotolerance), whereas long-term treatment induces intrinsic vascular changes, eg, a loss of nitrovasodilator-responsiveness (vascular tolerance). This is caused by increased vascular superoxide production and a supersensitivity to vasoconstrictors secondary to a tonic activation of protein kinase C. NADPH oxidase(s) and uncoupled endothelial nitric oxide synthase …
Hypoxia-induced dysfunction of rat diaphragm
2004
Contains fulltext : 47331.pdf (Publisher’s version ) (Closed access) Oxidants may play a role in hypoxia-induced respiratory muscle dysfunction. In the present study we hypothesized that hypoxia-induced impairment in diaphragm contractility is associated with elevated peroxynitrite generation. In addition, we hypothesized that strenuous contractility of the diaphragm increases peroxynitrite formation. In vitro force-frequency relationship, isotonic fatigability, and nitrotyrosine levels were assessed under hypoxic (Po(2) approximately 6.5 kPa) and hyperoxic (Po(2) approximately 88.2 kPa) control conditions and also in the presence of authentic peroxynitrite (60 min), ebselen (60 min), and t…