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Registros recuperados: 8
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Free radical chemistry in biological systems Biol. Res.
VALDEZ,LAURA B; LORES ARNAIZ,SILVIA; BUSTAMANTE,JUANITA; ALVAREZ,SILVIA; COSTA,LIDIA E; BOVERIS,ALBERTO.
Mitochondria are an active source of the free radical superoxide (O2-) and nitric oxide (NO), whose production accounts for about 2% and 0.5% respectively, of mitochondrial O2 uptake under physiological conditions. Superoxide is produced by the auto-oxidation of the semiquinones of ubiquinol and the NADH dehydrogenase flavin and NO by the enzymatic action of the nitric oxide synthase of the inner mitochondrial membrane (mtNOS). Nitric oxide reversibly inhibits cytochrome oxidase activity in competition with O2. The balance between NO production and its utilization results in a NO intramitochondrial steady-state concentration of 20-50 nM, which regulates mitochondrial O2 uptake and energy supply. The regulation of cellular respiration and energy production...
Tipo: Journal article Palavras-chave: Superoxide radical; Nitric oxide; Peroxynitrite; Mitochondria; Apoptosis; Aging.
Ano: 2000 URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602000000200005
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Ghost protein damage by peroxynitrite and its protection by melatonin BJMBR
Di Mascio,P.; Dewez,B.; Garcia,C.R.S..
We have studied the effect of peroxynitrite (ONOO-) on the membrane cytoskeleton of red blood cells and its protection by melatonin. Analysis of the protein fraction of the preparation by SDS-PAGE revealed a dose-dependent (0-600 µM ONOO-) disappearance at pH 7.4 of the main proteins: spectrin, band 3, and actin, with the concomitant formation of high-molecular weight aggregates resistant to reduction by ß-mercaptoethanol (2%) at room temperature for 20 min. These aggregates were not solubilized by 8 M urea. Incubation of the membrane cytoskeleton with ONOO- was characterized by a marked depletion of free sulfhydryl groups (50% at 250 µM ONOO-). However, a lack of effect of ß-mercaptoethanol suggests that, under our conditions, aggregate formation is not...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Peroxynitrite; Melatonin; Spectrin; Protein; Ghost; Thiols.
Ano: 2000 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2000000100002
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Nitric Oxide: Oxygen Radical Interactions in Atherosclerosis Biol. Res.
RUBBO,HOMERO; BATTHYANY,CARLOS; RADI,RAFAEL.
Atherosclerosis is one of the most common diseases and the principal cause of death in western civilization. The pathogenesis of this disease can be explained on the basis of the ‘oxidative-modification hypothesis,’ which proposes that low-density lipoprotein (LDL) oxidation represents a key early event. Nitric oxide (.NO) regulates critical lipid membrane and lipoprotein oxidation events by a) contributing to the formation of more potent secondary oxidants from superoxide (i.e.: peroxynitrite), and b) its antioxidant properties through termination reactions with lipid radicals to possibly less reactive secondary nitrogen-containing products (LONO, LOONO). Relative rates of production and steady state concentrations of superoxide and .NO and cellular sites...
Tipo: Journal article Palavras-chave: Antioxidants; Free radicals; Lipid oxidation; Low density lipoprotein oxidation; Nitric oxide; Peroxynitrite.
Ano: 2000 URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602000000200017
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Novel donors of nitric oxide derived of S-nitrosocysteine possessing antioxidant activities BJMBR
Petit,C.; Bernardes-Genisson,V.; Hoffmann,P.; Souchard,J.-P.; Labidalle,S..
Novel S-nitrosothiols possessing a phenolic function were investigated as nitric oxide (NO) donors. A study of NO release from these derivatives was carried out by electron spin resonance (ESR). All compounds gave rise to a characteristic three-line ESR signal in the presence of the complex [Fe(II)(MGD)2], revealing the formation of the complex [Fe(II)(MGD)2(NO)]. Furthermore, tests based on cytochrome c reduction were performed in order to study the ability of each phenolic disulfide, the final organic decomposition product of S-nitrosothiols, to trap superoxide radical anion (O2-). This study revealed a high reactivity of 1b and 3b towards O2-. For these two compounds, the respective inhibitory concentration (IC) 50 values were 92 µM and 43 µM.
Tipo: Info:eu-repo/semantics/article Palavras-chave: Nitric oxide; S-nitrosothiols (thionitrites); Antioxidant; Peroxynitrite.
Ano: 1999 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1999001100011
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Polyphenols and Red Wine as Antioxidants against Peroxynitrite and other Oxidants Biol. Res.
VALDEZ,LAURA B; ÁLVAREZ,SILVIA; ZAOBORNYJ,TAMARA; BOVERIS,ALBERTO.
The antioxidant capacity of polyphenols (+)-catechin, (-)-epicatechin and myricetin, and of different types of red wines (Cabernet Sauvignon, Malbec and blended wine) was evaluated by three assays. (a) NADH oxidation by peroxynitrite (ONOO-): the ONOO- scavenging activity was higher for myricetin (IC50=35 µM) than for (+)-catechin (IC50=275 µM) and (-)-epicatechin (IC50=313 µM). (b) Peroxynitrite initiated chemiluminescence in rat liver homogenate: (-)-epicatechin (IC50=7.0 µM) and (+)-catechin (IC50=13 µM) were more potent than myricetin (IC50=20 µM) in inhibiting the chemiluminescence signal. (c) Lucigenin chemiluminescence in aortic rings: (-)-epicatechin (IC50=15 µM) and (+)-catechin (IC50=18 µM) showed higher antioxidant capacity than myricetin...
Tipo: Journal article Palavras-chave: Antioxidant capacity; Peroxynitrite; Polyphenols; Red wines; Superoxide anion.
Ano: 2004 URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602004000200014
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Protein 3-nitrotyrosine formation during Trypanosoma cruzi infection in mice BJMBR
Naviliat,M.; Gualco,G.; Cayota,A.; Radi,R..
Nitric oxide (·NO) is a diffusible messenger implicated in Trypanosoma cruzi resistance. Excess production of ·NO and oxidants leads to the generation of nitrogen dioxide (·NO2), a strong nitrating agent. Tyrosine nitration is a post-translational modification resulting from the addition of a nitro (-NO2) group to the ortho-position of tyrosine residues. Detection of protein 3-nitrotyrosine is regarded as a marker of nitro-oxidative stress and is observed in inflammatory processes. The formation and role of nitrating species in the control and myocardiopathy of T. cruzi infection remain to be studied. We investigated the levels of ·NO and protein 3-nitrotyrosine in the plasma of C3H and BALB/c mice and pharmacologically modulated their production during...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Peroxynitrite; Nitric oxide; Nitrotyrosine; Free radicals; Trypanosoma cruzi; Chagas' disease.
Ano: 2005 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2005001200011
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Role of nitric oxide and superoxide in Giardia lamblia killing BJMBR
Giardia lamblia trophozoites were incubated for 2 h with activated murine macrophages, nitric oxide (NO) donors or a superoxide anion generator (20 mU/ml xanthine oxidase plus 1 mM xanthine). Activated macrophages were cytotoxic to Giardia trophozoites (~60% dead trophozoites). This effect was inhibited (>90%) by an NO synthase inhibitor (200 µM) and unaffected by superoxide dismutase (SOD, 300 U/ml). Giardia trophozoites were killed by the NO donors, S-nitroso-acetyl-penicillamine (SNAP) and sodium nitroprusside (SNP) in a dose-dependent manner (LD50 300 and 50 µM, respectively). A dual NO-superoxide anion donor, 3-morpholino-sydnonimine hydrochloride (SIN-1), did not have a killing effect in concentrations up to 1 mM. However, when SOD (300 U/ml)...
Tipo: Info:eu-repo/semantics/other Palavras-chave: Nitric oxide; Macrophage; Peroxynitrite; Giardia lamblia; Cytotoxicity; Superoxide.
Ano: 1997 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1997000100015
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Uptake of NO-releasing drugs by the P2 nucleoside transporter in trypanosomes BJMBR
Soulère,L.; Hoffmann,P.; Bringaud,F.; Périé,J..
Nitric oxide (NO·) has been identified as a principal regulatory molecule of the immune system and the major cytotoxic mediator of activated immune cells. NO· can also react rapidly with a variety of biological species, particularly with the superoxide radical anion O2·- at almost diffusion-limited rates to form peroxynitrite anion (ONOO-). ONOO- and its proton-catalyzed decomposition products are capable of oxidizing a great diversity of biomolecules and can act as a source of toxic hydroxyl radicals. As a consequence, a strategy for the development of molecules with potential trypanocidal activities could be developed to increase the concentration of nitric oxide in the parasites through NO·-releasing compounds. In this way, the rate of formation of...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Nitric oxide; Peroxynitrite; Thionitrite; S-nitrosothiol; Adenosine.
Ano: 1999 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1999001100016
Registros recuperados: 8
Primeira ... 1 ... Última
 

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