RESUMO
Fecal excretion of leukotriene C4 was determined in 26 individuals with dysentery and in 19 healthy controls. Of the patients, five were infected with Shigella dysenteriae type 1, 15 were infected with Shigella flexneri, two were infected with Shigella boydii, and four were infected with Shigella sonnei. Three of the healthy controls were infected with non-dysenteriae Shigellae. All isolates of Shigella dysenteriae type 1 produced Shiga toxin; the other strains were not toxigenic. Patients with dysentery due to Shigella dysenteriae type 1 excreted higher concentrations of leukotriene C4 (median, 3,234 pg/0.05 g of feces) than either ill individuals infected with non-dysenteriae Shigellae (median, 202 pg/0.05 g) or healthy carriers (median, 145 pg/0.05 g) and uninfected controls (median, 129 pg/0.05 g). We propose that Shiga toxin stimulates intestinal mast cells, which release leukotriene C4, contributing to the inflammatory response in Shigella dysenteriae type 1-associated dysentery.
Assuntos
Disenteria Bacilar/metabolismo , Fezes/química , Leucotrieno C4/metabolismo , Shigella dysenteriae , Adulto , Toxinas Bacterianas/genética , Toxinas Bacterianas/metabolismo , Criança , Pré-Escolar , DNA Bacteriano/análise , Fezes/microbiologia , Feminino , Guatemala , Humanos , Lactente , Masculino , Toxina Shiga I , Shigella/isolamento & purificação , Shigella dysenteriae/isolamento & purificação , Shigella dysenteriae/metabolismoRESUMO
The percentage of peripheral blood lymphocytes forming rosettes with sheep erythrocytes (E-rosettes) was determined in 33 severely malnourished Guatemalan children, and in two groups of clinically well but mildly growth retarded children from the same environment. Mean E-rosettes in the acutely ill patients was lower than the value observed in the mildly malnourished children, although there was considerable overlap between groups. These data differ from previously published studies of severely malnourished children from other parts of the world in that not all patients had decreased values for E-rosettes, in contrast to the uniform depression reported by others. As all patients were clinically similar, the results suggest that there may be specific nutrient defects associated with protein-energy malnutrition that particularly affect immune function. In addition, in vitro incubation of lymphocytes from the acutely malnourished children with the thymic factor, thymosin fraction 5, increased the percentage of E-rosettes in a dose-dependent fashion. These data suggest that immature, thymosin-responsive T cells are present in circulation. It is possible that in vivo thymosin administration may be beneficial for malnourished individuals.
Assuntos
Linfócitos/imunologia , Desnutrição Proteico-Calórica/imunologia , Diferenciação Celular , Células Cultivadas , Pré-Escolar , Feminino , Humanos , Lactente , Linfócitos/efeitos dos fármacos , Masculino , Formação de Roseta , Timosina/análogos & derivados , Timosina/farmacologiaRESUMO
Polyparasitism appears to be the rule, rather than the exception, both in populations and in individuals in the developing countries of the world. Thus, polyparasitism represents coendemicity in the epidemiologic sense and simultaneous infections in individual patients in the clinical sense. The effects of polyparasitism are often clinically inapparent. In some situations, however, combined infections may exacerbate clinical manifestations. Coexistent infections may also, under some circumstances, suppress disease symptoms. The possibility of either synergistic or antagonistic effects must therefore be considered in planning public-health intervention intervention programs, and the priorities or strategies selected may need to be altered accordingly. There are few available data at present that are suitable for evaluation of the real consequences of polyparasitism, in part because of the many confounding variables involved and the lack of prospective studies. Therefore, future intervention programs should be accompanied by an epidemiologic research component designed to detect clinical or laboratory changes in parasitic and other infections or in host responses.
Assuntos
Países em Desenvolvimento , Distúrbios Nutricionais/complicações , Doenças Parasitárias/epidemiologia , Adolescente , Afeganistão , Ascaríase/sangue , Ascaríase/complicações , Ascaríase/epidemiologia , Chade , Criança , Desenvolvimento Infantil , Pré-Escolar , Egito , Guatemala , Humanos , Lactente , Recém-Nascido , Madagáscar , Malária/complicações , Doenças Parasitárias/complicações , Peru , Esquistossomose/complicações , Tricuríase/sangue , Tricuríase/complicações , Tricuríase/epidemiologiaRESUMO
Phagocytic host defence mechanisms require both normally functioning cells and humoral factors. For example, activated complement components and/or specific immunoglobulin are essential for effective ingestion and killing of bacteria by neutrophils, and complement is especially important early in infection, before specific antibody has been produced. Abnormalities of serum complement have previously been reported in malnutrition, and the present study investigated the levels of serum opsonins in children with protein-energy malnutrition (PEM).Opsonic activity for Escherichia coli and Staphylococcus aureus was depressed in acute PEM patients, but recovered to higher levels with treatment. This depression was detected only when low concentrations of serum (10-20 ml/litre) were used. Marked and persistent opsonin deficiencies were associated with poor clinical response. Reduced opsonic activity may adversely affect host defence mechanisms and contribute to morbidity and mortality from pyogenic infections in PEM. Replacement therapy with fresh or fresh frozen plasma might restore opsonic activity in these patients and reduce the risk of septicaemia and its attendant high mortality.