RESUMO
Tumour necrosis factor (TNF)-alpha is crucial for resistance to Trypanosoma cruzi acute infection, but there is scant information on its role during the chronic phase. To address this issue, we analysed whether a short treatment with a TNF-alpha blocker affected the course and characteristics of chronic disease in a rat experimental model of T. cruzi infection. An anti-TNF-alpha agent (infliximab) was administered during the chronic phase for a period of 4 weeks (3 mg/kg/week), while control infected rats were inoculated with saline physiological solution. Search for parasites yielded non-successful results in all infected groups, irrespective of treatment. Nevertheless, the presence of T. cruzi kDNA in heart tissue was detected in infected and infected plus treated animals. Because infliximab might induce changes in the anti-parasite cytokine response, circulating levels of interleukin (IL)-10, interferon-gamma and nitric oxide were evaluated. An increase in IL-10 levels was observed only in the infected group treated with the anti-TNF-alpha blocker compared to the remaining groups (P < 0.05). A clear attenuation of histological damage associated with a diminution of cardiac TNF-alpha mRNA expression was observed in the infected and treated animals compared to the infected and non-treated group. Blocking of TNF-alpha during a relatively short period in chronically infected rats did not lead to evident parasite reactivation but reduced myocarditis severity significantly, indicating a role of this cytokine in the pathogenesis of chronic myocardial damage.
Assuntos
Anticorpos Monoclonais/uso terapêutico , Cardiomiopatia Chagásica/tratamento farmacológico , Imunossupressores/uso terapêutico , Trypanosoma cruzi , Fator de Necrose Tumoral alfa/antagonistas & inibidores , Animais , Anticorpos Monoclonais/farmacologia , Anticorpos Antiprotozoários/imunologia , DNA de Protozoário/análise , Coração/parasitologia , Imuno-Histoquímica , Imunossupressores/farmacologia , Infliximab , Masculino , Modelos Animais , Parasitemia/diagnóstico , RNA Mensageiro/análise , Distribuição Aleatória , Ratos , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Trypanosoma cruzi/genética , Fator de Necrose Tumoral alfa/genética , Fator de Necrose Tumoral alfa/imunologiaRESUMO
The well-established model of Chagas' disease in "l" rats was used to evaluate the effects of three injections of heat-killed Gordonia bronchialis, Rhodococcus coprophilus or saline on Trypanosoma cruzi parasitaemia and acute and chronic myocarditis, sequelae of the infection. Two vaccinating injections were given prior to challenge with T. cruzi, and the third, immunotherapeutic, injection was given 7 days after challenge. Treatment with either actinomycete significantly reduced acute parasitaemia (p<0.04), modified cellular infiltration during acute myocarditis and limited chronic myocarditis (p<0.03) in comparison with the saline-treated control animals. Immunological investigations showed that both bacterial preparations achieved their results through different mechanisms. The relevance of our findings to human Chagas' disease is discussed.
Assuntos
Actinomycetales/imunologia , Doença de Chagas/imunologia , Imunização , Animais , Anticorpos Antiprotozoários/sangue , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Cardiomiopatia Chagásica/imunologia , Microbiologia Ambiental , Imunoglobulina G/sangue , Masculino , Parasitemia/prevenção & controle , Ratos , SuspensõesAssuntos
Antígenos de Protozoários/imunologia , Artrite Experimental/imunologia , Artrite Infecciosa/imunologia , Doença de Chagas/imunologia , Trypanosoma cruzi/imunologia , Animais , Artrite Experimental/complicações , Artrite Experimental/patologia , Feminino , Imunidade Celular , Masculino , Ratos , Ratos EndogâmicosRESUMO
Si aceptamos el concepto de que el tiempo "comprometido" es aquel que el adolescente emplea dedicandose al estudio o trabajo y a actividades fisiologicas (sueno, alimentacion, etc.). son las horas restantes lo que definiriamos como "tiempo libre" delimitando de este modo un tiempo nuevo para sus actos y aspiraciones. Los adolescentes pueden ocupar el tiempo libre con actividades reales y posibles cada vez mas seductoras ya que las distracciones son mas numerosas y variadas que en anos pasados.La expansion del numero de automoveis, el incremento de los medios de difusion (prensa, cine, radio, television), el desarrollo de las asociaciones o grupos adecuados a los gustos, manias y/o pasiones son algunos ejemplos. Todo ello ha contribuido a aumentar el placer de las actividades durante el tiempo libre. Pueden entonces utilizar su tiempo libre, ya sea para descansar, divertirse, desarrollar algunas de sus afinidades o realizar practica deportiva.}
Assuntos
Humanos , Personalidade , Psicologia do AdolescenteRESUMO
Si aceptamos el concepto de que el tiempo "comprometido" es aquel que el adolescente emplea dedicandose al estudio o trabajo y a actividades fisiologicas (sueno, alimentacion, etc.). son las horas restantes lo que definiriamos como "tiempo libre" delimitando de este modo un tiempo nuevo para sus actos y aspiraciones. Los adolescentes pueden ocupar el tiempo libre con actividades reales y posibles cada vez mas seductoras ya que las distracciones son mas numerosas y variadas que en anos pasados.La expansion del numero de automoveis, el incremento de los medios de difusion (prensa, cine, radio, television), el desarrollo de las asociaciones o grupos adecuados a los gustos, manias y/o pasiones son algunos ejemplos. Todo ello ha contribuido a aumentar el placer de las actividades durante el tiempo libre. Pueden entonces utilizar su tiempo libre, ya sea para descansar, divertirse, desarrollar algunas de sus afinidades o realizar practica deportiva.}