[New process for screening of drugs in experimental infection with Trypanosoma cruzi]. / Novo processo para triagem de medicamentos na infecção experimental pelo Trypanosoma cruzi.

We propose a screening process for detection of therapeutic activity of drugs against experimental infection with Trypanosoma cruzi. It is based on the use of infected triatominae that are fed on mice which have received the study drug. Blood meals are made at different time schedule in order to adapt with serum drug levels. The digestive tube of the hemiptera will, thus, work as a suitable structure for examination. In a initial observation, benzonidazole was used, and was shown to be only partially active at least in the conditions of this new procedure.

[Evaluation of the therapeutic activity of itraconazole in chronic infections, experimental and human, by Trypanosoma cruzi]. / Avaliação da atividade terapêutica do itraconazol nas infecções crônicas, experimental e humana, pelo Trypanosoma cruzi.

Other authors have demonstrated that itraconazole has antiparasitic activity against Trypanosoma cruzi both in vitro and in animal acute infection. Because of these observations, we decided to evaluate the chronic phase of this protozoal disease, since it is the most important form under a clinical and assistential point of view. We studied an infected mouse model as well as human cases of Chagas' disease. One hundred mg/kg/day by gastric tube, and 100 or 200 mg/day orally were given, respectively, during three months, without showing any beneficial effect, at least with the adopted methods.

[Attempts to culturing triatominae in the laboratory using "in vitro" feeding]. / Tentativas de criação de triatomíneos em laboratório por meio de alimentação "in vitro".

In order to simplify breeding of triatominae in the laboratory, for performing xenodiagnosis and other biologic studies, we tried to feed the insects "in vitro" with citrated or defibrinated blood from commercially abated chicken. Two types of efficacy observations were carried out with Triatoma infestans: a) analysis of the chaining of successive nymphal stages, viability of satisfactory matching, fertile oviposition and adequate reproduction; b) assessment of viability and infectivity of Trypanosoma cruzi in the insects. As a conclusion, it became evident that, despite operational easiness, the objectives were not achieved, since the classical procedure used as the control, was always superior.

[Viability of Trypanosoma cruzi in sugar cane juice]. / Observações sobre a viabilidade do Trypanosoma cruzi no caldo da cana.

In Catolé do Rocha, State of Paraíba, Brasil several people were concomitantly contaminated by Chagas' disease and had the acute form of the infection. Because of this event, the hypothesis that Trypanosoma cruzi might have been transmitted by the digestive route, through the ingestion of accidentally contaminated sugar cane juice, was made. In the present study, we verified that the parasite has remained viable for four hours in the liquid, at room temperature. We have also demonstrated that, after one hour, it was capable of promoting infection in one mouse, by gastric tube administration. These observations enhance the interest on this alternative mechanism of disease transmission.

[Use of immunosuppressed mice in an attempt to improve the diagnosis of infection by Trypanosoma cruzi]. / Utilização de camundongos imunodeprimidos como tentativa de aprimoramento do diagnóstico da infecção pelo Trypanosoma cruzi.

In order to demonstrate low level parasitemias of Trypanosoma cruzi, a procedure based on the pharmacologic development of immunosuppression and subsequente innoculation of a test blood specimen was evaluated in mice. Prednisone was effective for the procedure and my be considered for diagnosis and for clinical and laboratorial follow-up of patients with Chagas'disease, submitted to heart transplantation. However, prednisone effectiveness depended from the level of parasitemia.

[Evaluation of the therapeutic activity of fluconazole in acute experimental infection caused by Trypanosoma cruzi]. / Avaliação da atividade terapêutica do fluconazol na infecção aguda, experimental, pelo Trypanosoma cruzi.

On hand of information that fluconazole can inhibit Trypanosoma cruzi, infection, an experimental investigation in acutely infected mice treated with 200 mg/kg daily of this drug during one month was carried out. Parasitemia patency, blood culture, sub-inoculation and histologic examination were the parameters used to evaluate the potential therapeutic activity of the drug. The results did not confirm the hypothesis, but it would be desirable to conduct new trials with this and other imidazole compounds.

[Effect of cyclosporin and prednisone on the acute phase of experimental infection of mice by Trypanosoma cruzi]. / Influência da ciclosporina e da prednisona na fase aguda da infecção experimental de camundongos pelo Trypanosoma cruzi.

The relations between immunosuppression and human or experimental infection by Trypanosoma cruzi have recently been the subject of great interest, specially because of the wider use of drugs acting on immunity and of organ transplantation programs, now in frank expansion. The use of cyclosporin turned necessary to know adequately its interactions with T. cruzi parasitosis, and this has been the objective of the present study, regarding the acute phase in mice, in comparison to the use of prednisone. It was verified that cyclosporin, alone or associated to the corticosteroids, promotes and enhancement of the parasitosis, as shown by the assessment of parasitemia, the amount of amastigote forms in the heart and the severity of cardiac inflammation. Such observations may be useful in clinical practice, calling the attention for necessity of a strict control of such cases an eventually the use of an antiparasitic agent.

[Evaluation of the usefulness of the Coprotest for parasitologic examination of feces]. / Avaliação da utilidade do "Coprotest" para exame parasitológico das fezes.

"Coprotest" is a device used for parasitological examination of the stools that has been marketed in Brazil with no previous literature support. Therefore, we decided to evaluate the usefulness of the procedure using "Coprotest", comparing it with the routine methods by Hoffman et al., Faust et al., and Rugai et al. Taking into consideration only positive samples, we observed the following figures, according to each technique: Hofmann et al.--98 (47.34%); Faust et al.--119 (57.48%); Rugai et al., only for larva detection--21 (10.14%); "Coprotest"--115 (55.55%). We concluded that "Coprotest" in addition to its operational qualities, has the merits that allow its use together with other techniques for parasitosis diagnosis. Nevertheless it has not modified the previous situation, since more than one technique must still be used, as we have noted for detection of Strongyloides stercoralis larvae in this instance.