RESUMO
The aim of this study was to assess DNA repair capacity in lymphocytes of children with protein calorie malnutrition using the single-cell gel electrophoresis (comet) assay. Repair capacity was assessed by estimating the relative decrease of DNA migration length 5, 15, 30, and 60 min after hydrogen peroxide treatment, in three groups of children: well-nourished (WN), well-nourished infected (WN-I), and malnourished infected (MN-I). In addition, the DNA migration length was evaluated in all groups before and after peroxide treatment. Comparison of mean migration lengths observed in WN and WN-I children showed significant differences at all times tested; between WN-I and MN-I differences were also observed, except after hydrogen peroxide exposure. This implies that lymphocytes of WN-I and MN-I children were equally sensitive to hydrogen peroxide. Nevertheless, the MN-I group clearly shows the greatest overall percentage of damaged cells at all times tested. In relation to repair capacity, at 5 min it was approximately 30% in both groups of well-nourished children, but only 20% in MN-I; 15 min after exposure, repair capacity increased to 51% in well-nourished children but only to 31% in MN-I; and at 60 min this capacity increased to 82% in well-nourished but only to 55% in MN-I. These data indicate that lymphocytes of malnourished children show a decreased capacity to repair hydrogen peroxide-induced DNA damage compared to that of well-nourished controls. This reflects that only malnutrition is associated with decreased DNA repair capacity. Additionally, the data confirm that severe infection and malnutrition are two factors clearly associated with increased DNA damage.
Assuntos
Transtornos da Nutrição Infantil/genética , Dano ao DNA/efeitos dos fármacos , Reparo do DNA/efeitos dos fármacos , Peróxido de Hidrogênio/farmacologia , Transtornos da Nutrição do Lactente/genética , Estudos de Casos e Controles , Pré-Escolar , Ensaio Cometa/métodos , Humanos , Lactente , Linfócitos/efeitos dos fármacos , Linfócitos/fisiologiaRESUMO
The frequency of sister-chromatid exchanges (SCE) and the rate of cell proliferation were evaluated through differential staining of sister chromatids in mitogen-stimulated cultured lymphocytes sampled from five well-nourished children, from seven severely malnourished children infected with bacterium, and from 10 severely malnourished children following treatment for infection with antimicrobial drugs 2 weeks before blood sampling. The replication indices at 48 h of culture were higher in both groups of malnourished children than in the well-nourished children, indicating either a faster response to PHA and/or a shorter cell cycle in lymphocytes of these patients. The average frequency of SCE per mitosis was also significantly higher than in the control group. The mitotic index was similar in the three groups of children. The lack of significant difference in response between the two groups of malnourished children suggests that the effects observed at the cytogenetic level are caused by severe malnutrition per se, and not by any associated infection.
Assuntos
Transtornos da Nutrição do Lactente/genética , Infecções/complicações , Ativação Linfocitária/genética , Desnutrição Proteico-Calórica/genética , Troca de Cromátide Irmã , Divisão Celular , Feminino , Gastroenteropatias/complicações , Gastroenteropatias/fisiopatologia , Humanos , Lactente , Transtornos da Nutrição do Lactente/complicações , Transtornos da Nutrição do Lactente/fisiopatologia , Infecções/fisiopatologia , Linfócitos/efeitos dos fármacos , Linfócitos/ultraestrutura , Masculino , Índice Mitótico , Fito-Hemaglutininas/farmacologia , Desnutrição Proteico-Calórica/complicações , Desnutrição Proteico-Calórica/fisiopatologia , Infecções Respiratórias/complicações , Infecções Respiratórias/fisiopatologiaRESUMO
El control de las tasas de desnutrición primaria en Chile ha permitido la detección de un número creciente de lactantes con desnutrición secundaria, como lo confirma esta investigación realizada entre los 1.542 lactantes ingresados a un centro de recuperación y estudio de desnutridos secundarios, en el período comprendido entre enero de 1985 y diciembre de 1990. Cada uno de los pacientes fue asignado, de acuerdo con el diagnóstico de ingreso, a una de las categorías de la clasificación de Hall, según la cual las afecciones genéticas y las malformaciones congénitas eran responsables de 40,1% de los ingresos (afecciones ciertamente genéticas 12,9%, enfermedades poligénicas-multifactoriales 15,8%, anomalías del desarrollo 9,1%, causadas por teratógenos 2,3%). El hallazgo de un número considerable de anomalías cromosómicas (n:54), en mayor proporción que en la población general, sugiere la conveniencia de realizar estudios citogenéticos en los pacientes con desnutrición secundaria y dismorfias o retardo psicomotor