[Specific treatment attempt, with ticlopidine, of patients with Chagas disease chronic phase]

In a previous study, ticlopidine decreased the parasitemia and mortality of mice infected by Trypanosoma cruzi. Therefore, this drug was administered to 12 patients with Chagas' disease, in the chronic phase. For 90 days, 150, 200 or 250 mg were utilized according to whether the recipients were children, adolescents or adults, respectively. A fully unsuccessful outcome was documented, both serologically as well as parasitologically.

[Protective effect of benznidazole against parasite reactivation in patients chronically infected with Trypanosoma cruzi and treated with corticoids for associated diseases]

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.

Specific chemotherapy of Chagas disease: a comparison between the response in patients and experimental animals inoculated with the same strains

Eleven strains of Trypanosoma cruzi were isolated from patients with Chagas disease in central Brazil by xenodiagnosis and inoculation into newborn mice. Biological characterization and isoenzyme analysis showed that 6 strains were type II (zymodeme 2) and 5 were type III (zymodeme 1). Patients were treated with benznidazole or benznidazole plus nifurtimox. Mice infected with each isolated strain were treated for comparison with the results obtained in the respective patient. Evaluation of cure of the patients was based on the indirect immunofluorescence test, complement fixation reaction and xenodiagnosis. For the mice, haemoculture, indirect immunofluorescence testing, xenodiagnosis and inoculation of blood into newborn mice were used. Tests were performed 3-6 months after the end of treatment. The cure rate was 66-100% in mice infected with type II strains and 0-9% in those infected with type III strains. The correlation between treatment results in patients and mice was 81.8% (9 of 11 cases). Type II strains were more susceptible to treatment, in contrast to type III strains which yielded the majority of therapeutic failures.

Morphometric investigations of the colon mucosa in chronic Trypanosoma cruzi infected rats

The objective of this investigation was to study the morphometry of the epithelial mucosa in the chronic phase of T. cruzi infection. Nine young female Wistar rats were inoculated with T. cruzi. Ten months after inoculation the animals were sacrificed and the proximal colon was collected for morphometric measurements of the thickness of the muscle layers, the number of neurons in the myenteric plexus, the crypt cell population (CCP), crypt cell production per crypt (CCPC) and turnover time (TT) of the epithelium. There was no muscle layer hypertrophy but there was significant denervation in the group inoculated with T. cruzi, which also showed hyperplasia of the epithelium. The data suggest that denervation of the myenteric plexus did not induce hypertrophy of the propria muscle layer itself but altered the morphometry of the colonic epithelium in T. cruzi-infected animals, with increased development of CCP and TT. It is possible that this epithelial hyperplasia, as a consequence of a longer crypt cell TT, increased the absorption and secretion activities of the colon, which in turn may participate in the genesis of the enteromegalies observed in the chronic phase of Chagas' Disease.

Parameters involved in binding of porcine pancreatic alpha-amylase with black bean inhibitor: role of sulfhydryl groups, chloride, calcium, solvent composition and temperature

The amylase inhibitor of black (kidney) beans (Phaseolus vulgaris; MW 53,000) forms a 1:1 stoichiometric complex with porcine pancreatic alpha-amylase (MW 52,000) at pH 5.40. The single sulfhydryl group of the inhibitor and the two sulfhydryl groups of alpha-amylase are not involved in recognition and binding. Chloride ions, required for activity of alpha-amylase at both pH 5.40 and 6.90, are important for inhibitor--enzyme binding at pH 6.90 but not at pH 5.40. Calcium-free alpha-amylase binds with the inhibitor. An increase in the ionic strength of the solvent increases the rate of binding of the inhibitor with alpha-amylase; a decrease in the dielectric constant decreases the rate of binding; and decreasing the temperature increases the dissociation constant, Kd, of the complex. These data support the hypothesis that hydrophobic interaction is of primary importance in complex formation. The activation energy, Ea, for complex formation was found to be 12.4 kcal/mol at pH 5.40 and 24.2 kcal/mol at pH 6.90. In the presence of the poor substrate, p-nitrophenyl-alpha-D-maltoside, the Ea for complex formation was 4.1 kcal/mol at pH 6.90.

[Susceptibility of the gastric mucosa to the damaging action of a bile salt in chronic chagasic rats]

Ratos inoculados previamente com a cepa Y do Trypanosoma cruzi (n = 15) e ratos-controles de mesma idade e sexo (n = 15) foram submetidos a estudo que consistiu no exame da mucosa gástrica após a exposição in vivo da mesma à solução acidificada de um sal biliar, o taurocolato de sódio (TC). Em 10 animais de cada grupo procedeu-se também à contagem dos neurônios do plexo mientérico do estômago e ao exame histopatológico dos corpos neuronais, feito em microscopia óptica convencional. Escores indicativos da gravidade das lesões produzidas pelo TC foram significativamente maiores (P < 0,002) nos ratos chagásicos que nos controles. A área erosada da mucosa gástrica, em % da área total da região glandular do estômago, foi significativamente maior (P0,10) entre os ratos chagásicos (1683,6 ± 449,7 n = 10) e os controles (1732,8 ± 401,1 n = 10). Não houve diferença qualitativa ao exame histopatológico dos corpos neuronais. Estes resultados indicam que, na doença de Chagas experimental crônica, a mucosa gástrica é mais sensível à ação lesiva do TC, o que sugere redução da citoproteção natural do estômago. Esta anormalidade não deve decorrer de alterações da inervação intrínseca que impliquem redução do número de neurônios intramurais do estômago, mas pode ser o resultado de alterações qualitativas não detectáveis à microscopia óptica.

[Experimental dilatation of the cecum and colon in rats. III. A model induced by prolonged administration of lactose in the diet of animals in the chronic phase of infection by the Y strain of T. cruzi]

Female Wistar albino rats (30 days of age), weighing about 60 g, were inoculated intraperitoneally with 1000 parasites/g of the Y strain of T. cruzi. The strain of T. cruzi has been maintained by in vivo passage of the parasites from mice to mice in the Department of Parasitology, Microbiology and Immunology, Medical School of Ribeirão Preto. Rats of the same sex and age were used as controls. One-hundred days after inoculation the animals were allocated into 4 groups: group I (control), divided into subgroup L (fed lactose for 4 weeks) and subgroup S (fed saccharose for 4 weeks); group II (inoculated), divided into subgroup L (fed lactose for 4 weeks) and subgroup S (fed saccharose for 4 weeks); group III (control), divided into subgroup L-S (fed lactose for 4 weeks and saccharose for the following 4 weeks) and subgroup S (fed saccharose for 8 weeks); and group IV (inoculated), divided into subgroup L-S (fed lactose for 4 weeks and saccharose for the following 4 weeks) and subgroup S (fed saccharose for 8 weeks). The disaccharide (lactose or saccharose) was added to a standard laboratory diet, 25 g/100 g of the final weight of the diet. At the end of the experimental periods the animals were sacrificed in ether anesthesia. The volume of the large intestine was measured, and the weight of cecum and colon were recorded.(ABSTRACT TRUNCATED AT 250 WORDS)

[Chagas' cardiomyopathy in children. Report of 2 cases]

Os Autores apresentam dois casos de cardiopatia chagásica crônica na infância, procedentes da região limítrofe entre os Estados de São Paulo e Minas Gerais. O objetivo é mostrar a possibilidade de contaminação natural da doença na área rural da região da qual as crianças são provenientes, assim como contribuir no entendimento fisiopatológico da Doença de Chagas. Ambos os casos apresentaram insuficiência cardíaca refratária aos recursos terapêuticos atuais, evoluindo para o óbito. São feitos comentários gerais sobre a fisiopatologia da doença, com base na literatura pertinente.

Imparied cyclic-AMP response to thyrotrophin in congenital hypothyroidism with thyroglobulin deficiency

A 19 year old man had congenital hypothyroidism and severely retarded development. His thyroid gland was not enlarged and laboratory findings included low serum concentration of T4 (2.8 microgram/100 ml) and T3 (16 ng/100 ml) with a high level of TSH (52 microU/ml) that rose to 192 microU/ml after TRH. 131I uptake by the thyroid was normal (41.5% at 24 h) and did not show a normal increase after exogenous TSH administration (49.5% at 24 h). The perchlorate discharge test was negative and no antibodies against thyroid antigens were found. Studies on the biopsy specimen revealed low iodide trapping by the thyroid slices and no formation of cyclic AMP after TSH was added to the medium. The endogenous TSH of the patient was biologically active increasing cyclic adenosine monophosphate c-AMP concentration in normal thyroid slices. No thyroglobulin was found in the thyroid tissue either by immunological or ultracentrifugational methods. An increased proportion of iodoalbumin was present in the serum. We postulate that the fundamental defect in this gland is an impaired generation of c-AMP by the defective thyroid cell and deficiency of thyroglobulin formation resulting in inadequate thyroxine and triiodothyronine synthesis.

[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)]

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)]

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.

[Parasitological survey, with special reference to schistosomiasis mansoni, conducted in the region of Jacupiranga (Ribeira valley, State of São Paulo). Survey of the location and distribution of planorbidian snails in the State of São Paulo. VII]

The results of a parasitological survey, emphasizing particularly schistosomiasis mansoni, are presented. The area under study was the district of Cajati, situated in the "município" of Jacupiranga (State of São Paulo, Brazil) near schistosomiasis-endemic areas in Vale do Ribeira. Though the presence of parasitized people by Schistosoma mansoni has been reported and focuses of Biomphalaria tenagophila, the species responsible for the spreading of the parasites through great areas of the state, has been localized, it has not been reported any autochthonous case nor the presence of schistosoma-infected planorbidian snails. As a contribution to the planorbidical chart of the State, it is reported as original the discovery of the species Drepanotrema cimex and D. depressissimum in that area. The detection of antitoxoplasmic antibodies in a sample of the studied population showed a significant prevalence rate corresponding to 76,4%.