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Superoxide (O2-) is the compound obtained when oxygen is reduced by one electron. For a molecule with an unpaired electron, O2- is surprisingly inert, its chief reaction being a dismutation in which it reacts with itself to form H2O2 and oxygen. The involvement of O2- in biological systems was first revealed by the discovery in 1969 of superoxide dismutase, an enzyme that catalyzes the dismutation of O2-. Since then it has been found that biological systems produce a bewildering variety of reactive oxidants, all but a few arising ultimately from O2-. These oxidants include O2- itself, H2O2 and alkyl peroxides, hydroxyl radical and other reactive oxidizing radicals, oxidized halogens and halamines, singlet oxygen, and peroxynitrite. These various oxidants... |
Tipo: Info:eu-repo/semantics/other |
Palavras-chave: NADPH oxidase; Superoxide; Oxidative stress; Antioxidant; Regulation; Host defense. |
Ano: 1997 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1997000200001 |
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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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Agudelo-Flórez,P.; López,J.A.; Redher,J.; Carneiro-Sampaio,M.M.S.; Costa-Carvalho,B.T.; Grumach,A.S.; Condino-Neto,A.. |
Chronic granulomatous disease (CGD) is an inherited disorder of the innate immune system characterized by a defective oxidative burst of phagocytes and subsequent impairment of their microbicidal activity. Mutations in one of the NADPH-oxidase components affect gene expression or function of this system, leading to the phenotype of CGD. Defects in gp91-phox lead to X-linked CGD, responsible for approximately 70% of CGD cases. Investigation of the highly heterogeneous genotype of CGD patients includes mutation analysis, Northern blot or Western blot assays according to the particular case. The aim of the present study was to use reverse transcription (RT)-PCR for the analysis of molecular defects responsible for X-linked CGD in eight Brazilian patients and... |
Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Superoxide; Phagocytes; Primary immunodeficiency; Respiratory burst; Neutrophils; Human. |
Ano: 2004 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2004000500001 |
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Setubal,SS; Pontes,AS; Furtado,JL; Kayano,AM; Stábeli,RG; Zuliani,JP. |
Envenomations caused by different species of Bothrops snakes result in severe local tissue damage, hemorrhage, pain, myonecrosis, and inflammation with a significant leukocyte accumulation at the bite site. However, the activation state of leukocytes is still unclear. According to clinical cases and experimental work, the local effects observed in envenenomation by Bothrops alternatus are mainly the appearance of edema, hemorrhage, and necrosis. In this study we investigated the ability of Bothrops alternatus crude venom to induce macrophage activation. At 6 to 100 ¼g/mL, BaV is not toxic to thioglycollate-elicited macrophages; at 3 and 6 ¼g/mL, it did not interfere in macrophage adhesion or detachment. Moreover, at concentrations of 1.5, 3, and 6 ¼g/mL... |
Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Snake venom; Bothrops; Macrophages; Phagocytosis; Superoxide; Protein kinase C; Inflammation. |
Ano: 2011 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1678-91992011000400010 |
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