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1.
Biochim Biophys Acta ; 1740(1): 68-73, 2005 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-15878743

RESUMO

Phenylketonuria (PKU) is an autossomal recessive disease caused by phenylalanine-4-hydroxylase deficiency, which is a liver-specific enzyme that catalyzes the hydroxylation of l-phenylalanine (Phe) to l-tyrosine (Tyr). The deficiency of this enzyme leads to the accumulation of Phe in the tissues and plasma of patients. The clinical characterization of this disease is mental retardation and other neurological features. The mechanisms of brain damage are poorly understood. Oxidative stress is observed in some inborn errors of intermediary metabolism owing to the accumulation of toxic metabolites leading to excessive free radical production and may be a result of restricted diets on the antioxidant status. In the present study we evaluated various oxidative stress parameters, namely thiobarbituric acid-reactive species (TBA-RS) and total antioxidant reactivity (TAR) in the plasma of PKU patients. The activities of the antioxidant enzymes catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were also measured in erythrocytes from these patients. It was observed that phenylketonuric patients present a significant increase of plasma TBA-RS measurement, indicating a stimulation of lipoperoxidation, as well as a decrease of plasma TAR, reflecting a deficient capacity to rapidly handle an increase of reactive species. The results also showed a decrease of erythrocyte GSH-Px activity. Therefore, it is presumed that oxidative stress is involved in the pathophysiology of the tissue damage found in PKU.


Assuntos
Estresse Oxidativo , Fenilcetonúrias/etiologia , Adolescente , Adulto , Criança , Pré-Escolar , Enzimas/sangue , Eritrócitos/enzimologia , Humanos , Peroxidação de Lipídeos , Fenilalanina/sangue , Fenilcetonúrias/sangue , Substâncias Reativas com Ácido Tiobarbitúrico/análise
2.
Rev. bras. farmacogn ; 15(1): 16-22, jan.-mar. 2005. tab
Artigo em Português | LILACS | ID: lil-570877

RESUMO

Extratos aquosos de vinte espécies de esponjas da costa Atlântica brasileira foram testados para verificação da presença de atividade lectínica e atividade hemolítica. Hemaglutinação para eritrócitos humanos e de distintos animais foi evidenciada em 12 dos 20 extratos testados. Os extratos das espécies Axinella corrugata, Chondrilla nucula, Chondrosia collectrix, Cinachyrella alloclada e Guitarra sp1. foram os que apresentaram maior atividade hemaglutinante. Dos doze extratos com atividade hemaglutinante dez tiveram a atividade inibida por um ou mais açúcares e/ou glicoproteínas. A lectina do extrato de Chondrilla nucula foi resistente à desnaturação térmica quando aquecida a 100 ºC por 60 minutos. Atividade hemolítica foi encontrada apenas nos extratos de Petromica citrina e Acervochalina sp. As espécies que apresentaram maior potencial para futuros estudos de suas lectinas foram Axinella corrugata, Chondrilla nucula e Chondrosia collectrix, em vista da maior atividade hemaglutinante apresentada por seus extratos, aliada à maior atividade específica.


Aqueous extracts of twenty species of sea sponges of the Brazilian Atlantic coast were tested with the aim of searching the presence of lectinic and hemolytic activity. Hemagglutinating activity for human erythrocytes and for distinct animals were found in 12 of the 20 tested extracts. The extracts of Axinella corrugata, Chondrilla nucula, Chondrosia collectrix, Cinachyrella alloclada and Guitarra sp1. were the ones that presented highest hemagglutinating activity. Ten of the 12 hemagglutinating extracts had the activity inhibited by one or more sugars or glycoproteins. The lectin from Chondrilla nucula was resistant to thermal denaturation when heated up to 100 ºC for 60 minutes. Hemolytic activity was only found in the extracts from Petromica citrina and Acervochalina sp. The species of sea sponges that showed major potential for futures studies of their lectins were Axinella corrugata, Chondrilla nucula and Chondrosia collectrix, due to the highest hemagglutinating activity presented by their extracts, allied to the highest specific activity.

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