The direct agglutination test for chronic Chagas's disease. The effect of pre-treatment of test samples with 2-mercaptoethanol.

The relative sensitivity and relative specificity of the direct agglutination (DA) test for the diagnosis of human Trypanosoma cruzi infection were studied in human serum samples, with and without previous treatment with 2-mercaptoethanol (2-ME), which were obtained from different areas of Brazil. Results obtained with these tests were related to those obtained with the indirect immunofluorescence (IIF) and indirect haemagglutination (IHA) tests. The DA test results from the sample not previously treated with 2-ME did not agree with those from the IIF and IHA tests. On the other hand, the DA test results from the sample previously treated with 2-ME agreed significantly (99.22%) with those from the IIF and IHA tests.

Immunoglobulin A antibodies to Trypanosoma cruzi antigens in digestive forms of Chagas' disease.

In an attempt to find a serological marker for the diagnosis of chronic digestive forms of Chagas' disease, we compared amastigote and trypomastigote antigens obtained from immunosuppressed mice infected with Trypanosoma cruzi (Y strain) with conventional epimastigote antigens to search for immunoglobulin A (IgA) antibodies. A total of 255 serum samples from patients with acute and chronic (indeterminate, digestive, and cardiac) forms of Chagas' disease and with nonchagasic diseases and from healthy individuals were studied. Amastigote antigens proved to be the most adequate for our purpose, since IgA antibodies could be detected in 23 of 25 serum samples from patients with digestive forms, with relative indices of sensitivity, specificity, and efficiency of 0.920, 0.911, and 0.912, respectively. These antigens also showed high reactivity with IgA antibodies, with a geometric mean titer of 16,635 (12.7 log2). IgA antibodies were detected in 16 of 28 serum samples from patients with the acute form as well, but this clinical form is easily distinguished from the chronic form by the demonstration of IgM antibodies. Poor results were seen with trypomastigote and epimastigote antigens. The finding of IgA antibodies in about 20% of indeterminate forms and 20% of cardiac forms, although in low titers, requires further investigation to ascertain their role as an early signal of gastrointestinal lesions. In addition, the amastigote antigens described here seem more convenient for use in endemic areas than those obtained from cell cultures because of their lower cost.

Taquicardia ventricular pelo uso de amiodarona. Relato de um caso. / Ventricular tachycardia by the use of amiodarone.Report of a case

O autores apresentam o caso de paciente que, durante esforco fisico, desenvolveu taquicardia ventricular, na vigencia de altas doses de amiodarona

Anticorpos EVI e NP na infeccao chagasica cronica. Estudo em pacientes com diferentes formas clinicas. / EVI and NP antibodies in chronic Chagas' infection.Study in patients with different clinical forms

Para verificar se existe correlacao entre os anticorpos EVI e NP e a infeccao chagasica cronica, foram estudados 56 pacientes sorologicamente positivos para o T. cruzi,que apresentavam diferentes formas clinicas desta infeccao. Foram tambem estudados 75 soros com reacoes negativas para T. cruzi, para determinar os titulos de EVI e NP que nao pertencem a esta populacao. Os resultados demonstram que titulo > ou igual a 1:32 podem ser tomados como positivos tanto para EVI quanto para NP. Considerando este titulo, verificamos que 69,6% e 70,1% dos pacientes chagasicos apresentam anticorpos EVI e NP respectivamente, e somente 3% dos individuos nao infectados apresentavam titulos de 1:32. Estes dados mostram a estreita relacao existente entre EVI, NP, e a infeccao chagasica. Porem, quando se analisou a presenca desses anticorpos em pacientes com as diferentes formas clinicas da doenca, nao foi encontrada diferenca significativa entre os grupos estudados