[Protective effect of benznidazole against parasite reactivation in patients chronically infected with Trypanosoma cruzi and treated with corticoids for associated diseases]. / Efeito protetor do benznidazol contra a reativação parasitária em pacientes cronicamente infectados pelo Trypanosoma cruzi e tratados com corticóide em virtude de afecções associadas.

Patients in the chronic phase of Chagas' disease and receiving corticoid because of concommitant diseases were treated with benznidazole, which was initiated at the same time of the use of corticoid in a group of 12 patients or 15 days afterwards in 6 patients. It has been proved in another paper that in the chronic phase of Chagas' disease corticoid use is associated with increased parasitemia, as evaluated by xenodiagnosis. In this study benznidazole use prevented this increase, and we suggest that in immunocompromised patients with chronic Chagas' disease the use of this drug could be useful.

[Nifurtimox as a prophylactic drug to prevent reactivation in chronic chagasic patients treated with corticoid for associated diseases]. / Efeito protetor do nifurtimox contra a reativação parasitária em pacientes cronicamente infectados pelo Trypanosoma cruzi e tratados com corticoide em virtude de afecções associadas.

Patients in the chronic phase of Chagas' disease and receiving corticoid because of concommitant diseases were treated with nifurtimox. We proved in another paper that in the chronic phase of Chagas' disease corticoid use is associated with increased parasitemia, as evaluated by xenodiagnosis. In this study nifurtimox use prevented this increase, and we suggest that in immunocompromised patients with chronic Chagas' disease the use of this drug could be useful.

[The influence of corticoids, in Chronic Chagas disease, administered in virtue of associated disorders]. / Influência de corticóide, na doença de Chagas crônica, administrado em virtude de afecções associdas.

Patients with chronic Chagas' disease and simultaneous medical problems treated with corticosteroid were studied in order to evaluate steroid influence on chronic Trypanosoma cruzi infection. Parasitological assessment, radiological and electrocardiographic studies as well as non specific tests were performed in patients and in a control group that included chronic infected patients not treated with steroid. Xenodiagnosis showed a clear increase in T. cruzi parasitemia, related to the corticosteroid dosage, without clinical manifestations during the study follow-up period.

[Early immunological aspects in rats infected by Trypanosoma cruzi. II. Soluble antigen circulation and the modifications of serum complement from animals in sucessive days of the infection (author's transl)]. / Aspectos imunitários iniciais observados em ratos infectados por Trypanosoma cruzi. II. A circulação de antígenos solúveis e as modificações do complemento sérico dos animais em dias sucessivos da infecção.

A group of rats was infected by the Y strain of T. cruzi and three animals were bled daily from the 4th to the 13th days. The sera obtained each day, after being mixed, were used for dosing serum complement and for acting as antigens in the CFT with a Chagas' disease serum. The amount of circulating antigen increased gradually, reached a maximum in the 5th and 6th days and then decreased up to the 10th day; thereafter it increased attaining a new maximum in the 11th day and again decreased up to the 13th day. The dosage of the complement showed that the 50 per cent unit was about 70 x 10(-4) in the first few days of the infection, reached 130 -- 135 x 10(-4) in the 7th and 8th days, and was back again to the initial levels in the 13th day. These results suggest a relation between the circulation of antigens, the formation of antigen antibody complexes, and the fixation of the complement by such complexes.

[Early immunological aspects in rats infected by Trypanosoma cruzi. I. Agglutination and immunofluorescence tests with antigen of trypomastigotes recovered in successive days of the infection (author's transl)]. / Aspectos imunitários iniciais observados em ratos infectados por Trypanosoma cruzi. I. Reações de aglutinação e de imunofluorescéncia com antígeno de tripomastigotas recuperados em dias sucessivos da infecção.

From rats infected with the Y strain of T. cruzi trypomastigotes were recovered in successive days to be used in agglutination tests (AT) and in direct immunofluorescence tests (DIT). Titres obtained in AT reached 1/640 with trypomastigotes in the fourth and fifth days, decreased to 1/160 in the sixth day and were negative in the seventh day; in the tenth day the titers were again up to 1/40 and reached 1/320 in the eleventh day. The DIT were negative with trypomastigotes in the fourth and fifth days, a few were positive in the sixth day and numerous were positive in the seventh day; again a few were positive in the tenth day and all were negative in the eleventh day. These results seems to indicate that the trypomastigotes are blocked by circulating antibodies when they are not agglutinated by immune sera in vitro.