Navegando por Assunto "Metemoglobina"

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Acesso aberto (Open Access)
Concentrações plasmáticas de primaquina e metemoglobinemia em pacientes com malária por Plasmodium vivax
(Universidade Federal do Pará, 2010) FERREIRA, Michelli Erica Souza; VIEIRA, José Luiz Fernandes; http://lattes.cnpq.br/2739079559531098
The vivax malaria is a disease that effects around 40% of the world, to treat it, chloroquine (150 mg) and primaquine (15 mg). This is an 8-aminoquinoline with tissue schizonticide action. Among the adverse effects enhance the capacity to hemoglobin oxidation, dose-dependent, which is exacerbated in individuals with glucose-6-phosphate dehydrogenase deficiency. When considering the lack of studies concerning the methemoglobin levels and its correlation with primaquine concentrations plasma in patients with vivax malaria, is justified this study using as tools to monitor the plasma primaquine concentrations and its correlation with methemoglobin levels. In this sense, it was followed up clinically and laboratory findings of 20 patients with vivax malaria before (D0) and after three (D3), seven (D7) and fourteen (D14) days starting the treatment, as well as validation of the method for primaquine determination by high performance liquid chromatography (HPLC). Methemoglobinemia was evaluated using the method of Hegesh et al. (1970) and glucose-6-phosphate dehydrogenase by colorimetric method of Brewer et al. (1962 ). The methodology validated was demonstrated efficient for primaquine determination, whose average levels at D3, D7 and D14 were 227 ± 106 ng / mL, 191 ± 97 ng / mL and 160 ± 128 ng/mL. In the analysis according to gender was not observed differences significant in the drug levels in several days of study. The average methemoglobin levels in D0, D3, D7 and D14 were 1.15 ± 0.9%, 4.1 ± 2%, 5.7 ± 2% and 3 ± 1.4%, respectively. There was an increase in the methemoglobin level after drug administration, without difference by gender. There was not significant correlation between the methemoglobin levels and primaquine concentrations plasma in both sexes. The coefficients of Pearson correlation for males and females were 0.8296 and 0.8137, respectively. We observed impaired expression of the enzyme glucose-6-phosphate dehydrogenase in six male patients without differences between the methemoglobin levels and primaquine concentrations plasma, compared with patients with expression normal of the enzyme.
Acesso aberto (Open Access)
Efeito protetor de antioxidantes na formação de metemoglobina induzida pelo metabólito dapsona-hidroxilamina in vitro
(Universidade Federal do Pará, 2017-07-11) VARELA, Everton Luiz Pompeu; MONTEIRO, Marta Chagas; http://lattes.cnpq.br/6710783324317390
Dapsone used in leprosy therapy its metabolite dapsone-hydroxylamine are potent pro-oxidant agents that cause acquired methemoglobinemia. For the treatment of this disease is used as antidote the Methylene Blue, however in high doses this antidote becomes pro-oxidant. In this sense, antioxidant substances may be potential alternatives to methylene blue for the treatment of methemoglobinemia. In this study we investigated the effect of antioxidants Ebselen, N-acetylcysteine, R-lipoic acid and L-lipoic acid on oxidative damage induced by dapsone-hydroxylamine in human erythrocytes, in vitro. Our results demonstrated that pre-treatment with antioxidants Ebselen, N-acetylcysteine, R-lipoic acid and S-lipoic acid prevented the formation of methemoglobin, reduction of glutathione and lipid peroxidation induced by the metabolite dapsone-hydroxylamine in human erythrocytes, In vitro. These substances were able to increase the antioxidant capacity of the erythrocyte associated with increased concentration of glutathione. Thus, antioxidants acted to reduce the oxidation of hemoglobin and / or directly or indirectly impeded the action of the metabolite dapsone-hydroxylamine. Our results indicate that the antioxidants tested can protect erythrocytes against oxidative damage under experimental conditions, suggesting that antioxidants may serve as the most effective and safe antidote in the treatment of methemoglobinemia.
Acesso aberto (Open Access)
Efeito protetor de antioxidantes na metemoglobina e no dano em dna induzidos pela dapsona-hidroxilamina in vitro
(Universidade Federal do Pará, 2016-06-21) GOMES, Antonio Rafael Quadros; MONTEIRO, Marta Chagas; http://lattes.cnpq.br/6710783324317390
Dapsone (DDS) is one of the drugs used in polychemotherapy of leprosy associated with rifampicin and clofazimine. Of these drugs, DDS is primarily responsible for adverse reactions, such as methemoglobinemia and hemolytic anemia. These reactions are related to the DDS metabolite, dapsone hydroxylamine (DDS-NOH). In an attempt to promote the reduction of toxic effects are studied alternative therapies with antioxidants. This work aimed to evaluate the protective effect of N-acetylcysteine (NAC), A. brasiliensis and Glutathione ethyl ester (GSH-EE) in methemoglobin (MetHb) and DNA damage induced by DDS-NOH in vitro , correlating to oxidative stress parameters. For this, suspensions of human erythrocytes to 50% were pre- and post-treated with NAC, A. brasiliensis and GSH-EE in different concentrations, being exposed groups DDS-NOH to induce the formation MetHb. It also assessed whether the activity of enzymes-SOD and CAT and GSH levels, TEAC and MDA. In leukocytes evaluated the induction of ROS intracellularly using DCFH-DA and the damage to DNA by comet assay. The results showed that the DDS-NOH metabolite was capable of inducing MetHb in vitro, this dose-dependent effect. Regarding the pre-treatment, all the antioxidants prevented MetHb formation induced by DDS-NOH, as well as post-treatment. For SOD, only the pre-treatment with NAC and A. brasiliensis reduced SOD activity. In the post-treatment, there was increased when treated with antioxidants. Pre-treatment with NAC and GSH-EE increased CAT activity, moreover A. brasiliensis reduced, as after treatment with antioxidants. As for GSH levels, pre-treatment with NAC and GSH increased A. brasiliensis, on the other hand, did not alter after treatment. Regarding TEAC did not change. With respect to oxidative damage in the pre-treatment A. brasiliensis and GSH-EE reduced MDA. In the post-treatment, there was an increase in group A. brasiliensis and reduced GSH-EE group. Only the NAC was shown to be effective in removing the intracellular ROS induced by DDS-NOH in leukocytes. While in erythrocytes, a NAC and A. brasiliensis were able to reduce this effect. In the study of the comet assay, the DDS-NOH was able to induce DNA damage in peripheral blood leukocytes, however this damage was reduced when treated with NAC and A. brasiliensis. It can be concluded from our data that the evaluated antioxidants have therapeutic potential in the prevention of MetHb and DNA damage induced by DDS-NOH in vitro, more effective NAC against these effects.
Acesso aberto (Open Access)
Metemoglobinemia em pacientes com malária por Plasmodium vivax em uso oral de primaquina
(2011-02) FERREIRA, Michelli Erica Souza; GOMES, Margarete do Socorro Mendonça; VIEIRA, José Luiz Fernandes
Primaquine can produce adverse reactions as toxicity to blood when used in the treatment of vivax malaria. This work aimed to determine methemoglobinemia in patients with vivax malaria receiving oral therapy with primaquine. Methods: Spectrophotometric quantification of methemoglobinemia and qualitative assay for glucose-6-phosphate dehydrogenase. Results: Methemoglobinemia ranged from 2.85 to 5.45% in male patients and 3.77 to 7.34% in female patients. Conclusions: A statistically significant increase in methemoglobinemia was observed following oral therapy with primaquine, with no clinical manifestations, and independent of sex and the qualitative expression of glucose-6-phosphate dehydrogenase.
Acesso aberto (Open Access)
Methemoglobinemia and dapsone levels in patients with leprosy
(2010-06) VIEIRA, José Luiz Fernandes; RIVERA, Juan Gonzalo Bardález; MARTINS, Ana de Nazaré Silva; SILVA, Jorge Pereira da; SALGADO, Claudio Guedes
The objective of this work was to determine the methemoglobinemia and correlate with dapsone levels in multibacillary leprosy patients under leprosy multi-drug therapy. Thirty patients with laboratory and clinical diagnosis of multibacillary leprosy were enrolled. Dapsone was analyzed by high performance liquid chromatography and methemoglobinemia by spectrophotometry. The mean dapsone concentrations in male was 1.42 g/mL and in female was 2.42 g/mL. The mean methemoglobin levels in male was 3.09 µg/mL; 191%, and in female was 2.84 ± 1.67%. No correlations were seen between dapsone levels and methemoglobin in male and female patients. Our results demonstrated that the dosage of dapsone in leprosy treatment does not promote a significant methemoglobinemia.