Effects of water deprivation on renal hydroelectrolytic excretion in chronically Trypanosoma cruzi-infected rats

The effect of an 8 hour-period of water deprivation on fluid and electrolyte renal excretion was investigated in male Wistar rats infected with the strain Sao Felipe (12SF) of Trypanosoma cruzi, in comparison with age and sex matched non-infected controls. The median percent reductions in the urinary flow (-40 per cent v -63 per cent) and excretion of sodium (-57 per cent v - 79 per cent) were smaller in chagasic than in control rats, respectively. So, chagasic rats excereted more than controls. On the other hand, the median percent decrement in the clearance of creatinine was higher in chagasic (-51 per cent) than in controls (-39 per cent). Thus, chagasic rats showed some disturbed renal hydroelectrolytic responses to water deprivation, expressed by smaller conservation, or higher excretion of water and sodium in association with smallerglotmerular filtration rate. This fact denoted an elevation in the fractional excretion of sodium and water.

Neuronal counting and parasympathetic dysfunction in the hearts of chronically Trypanosoma cruzi infected rats

Dez ratos machos Wistar cronicamente infectados pelas cepas Colombiana, Sao Felipe (12SF), e Y do Trypanosoma cruzi, foram submetidos, apos 8 meses de infeccao, juntamente com dez animais controles, ao teste da resposta bradicardica barorreflexa pela injecao endovenosa de fenilefrina. Seis ratos chagasicos exibiram disfuncao cardiaca parassimpatica, caracterizada pela depressao do indice da resposta bradicardica barorreflexa. Embora o estudo histologico dos coracoes chagasicos mostrasse lesoes dos ganglios atriais, a contagem dos neuronios em cortes seriados, nao apresentou reducao numerica significativa dos mesmos.

Pentavalent antimonial nephrotoxicity in the rat

Estudou-se a funcao renal de ratos tratados com Glucantime (Antimoniato de Meglumine, Rhodia) e Pentostam (estibogloconato de Sodio, Wellcome) na dose de 30 mg de "Sb POT v" por 100g de peso por dia, durante 30 dias. Observou-se um disturbio na concentracao urinaria, que foi reversivel 7 dias apos cessada a administracao das drogas. O estudo histopatologico do rim, por meio da microscopia optica, nao evidenciou alteracoes significativas. Por outro lado, ratos tratados com altas doses dos antimoniais (220mg de "Sb POT v" por 100g de peso por dia) mostraram alteracoes funcionais e histopatologicas renais compativeis com necrose tubular aguda

Ambulatory assessment of cardiac autonomic function in chagas's heart disease patients based on indexes of R-R interval variation in the valsalva maneuver

1. The reflex cardiac autonomic function of Chagas' heart disease patients was evaluated by a simple, nonivasive and inexpensive ambulatory method as an alternative to the complex or invasive methods or drug tests hitherto used. Variations in the R-R interval during the Valsava maneuver was quantified in 33 outpatients with Chagas's cardiopathy without heart failure aged 38 ñ 9 yers, and compared to 30 healthy control subjects aged 31 ñ 8 years (P > 0.05). 2. Each subject carried out 3 to 4 Valsalva maneuvers in the supine position for 20 s at an intraoral pressure of 40 mmHg. Variations of R-R interval were calculated from the electrocardiogram whic was recorded continuously from 10 s before to 90 s after the maneuver when the recovery phase had alredy started. 3. The chagasic group presented lower relative tachycardia (shortest R-R minus control R-R/control R-R) (-27.9 ñ 8.4%, mean ñ SD) and Valsalva ratio (longest R-R/shortest R-R) (1.67 ñ 0.3) than the control group (34.2 ñ 6.5% and 1.93 ñ 0.3, respectively) (P < 0.01). The time for maximum R-R interval variation (shortest R-R to longest R-R) was longer (18.0 ñ 7.2s), and the velocity of this variations (longest R-R minus shortest R-R divided by shortest R-R/time for the maximum R-R variation) was lower (4.8 ñ3.5%/s) in the chagasic patients (P < 0.01) than in the controls (11.1 ñ 5.4 s and 10.8 ñ 6.0%/s, respectively). The mean relative bradycardia (longest R-R minus control R-R/control R-R) of the chagasic group (18.5 ñ 13.5%) was statistically similar (P > 0.05) to that of the control group (25.6 ñ 16.5%). 4. In 51% (17/33) of the chagasic patients, at least one significantly altered index was observed to exceed ñ 2 SD of the respective control mean, and for 3 of them (10% of the total) all the indexes were abnormal. In 49% (16/33) of the patients no abnormal index was observed. 5. These date show that varyng degress of cardiac autonomic dysfunction may be detected in a simple manner in ambulatory outpatients with Chagas's heart disease, with results similar to those obtained with application of complex or invasive tests. In all likelihood, the altered Valsalva R-R interval variation indexes in the present chagasic patients resulted from depressed parasympathetic activity on the heart consequent to the Chagas cardiac devervation. However, associated sympathetic dysfunction should not be ruled out as a possible secondary secondary cause

Lesöes cardíacas em ratos Wistar inoculados com diferentes cepas do Trypanosoma cruzi / Cardiac lesions in Wistar rats infected with different strains of Trypanosoma cruzi

Ratos albinos Wistar infectados com diferentes inóculos das cepas Y, Colombiana (COL) e Säo Felipe (12SF) do Trypanosoma cruzi desenvolveram parasitemia elevada entre 14 e 21 dias, a qual tornou-se desprezível ou desapareceu completamente ao final da 4ª semana. As lesöes do coraçäo foram avaliadas, semiquantitativamente, pelo sistema de "scores", conforme a intensidade e a extensäo da inflamaçäo, nas diferentes estruturas do órgäo, tendo sido observado que: a) na fase inicial (aguda) da infecçäo, os animais mortos espontaneamente ou em conseqüência do acidente anestésico apresentaram cardite de intensidade moderada a acentuada, näo havendo diferença em relaçäo as cepas utilizadas; as diferentes estruturas do coraçäo estavam uniformemente comprometidas; b) na fase crônica da infecçäo observou-se cardite de grau leve a moderado e as lesöes foram mais freqüentes e intensas quanto maior o inóculo empregado; no entanto, inóculos baixos só produziram lesöes quando a cepa utilizada foi a Colombiana. Trombose mural nos átrios e dilataçäo da ponta do ventrículo esquerdo foram observadas em 20% dos animais, independetemente da cepa. Na fase crônica 15% dos animais apresentaram miocardite crônica com fibrose, associada a hipertrofia das miocélulas. Os AA confirmam ser o rato albino suscetível a infeccäo chagásica e, portanto, um modelo útil no estudo das manifestaçöes cardíacas da Doença de Chagas

Praziquantel no tratamento da esquistossomose mansoni. / Praziquantel in the treatment of schistosomiasis mansoni

Tratamos de 135 pacientes, portadores de esquistossomose mansoni, com o praziquantel por via oral. Os doentes foram divididos em tres grupos de 45 casos, conforme o nemero de ovos por grama de fezes: I com 95 a 500, II com 501 a 1000 e III com mais de 1000. As doses empregadas, em 15 pacientes de cada grupo, foram, respectivamente, 30 e 40 mg/kg de peso corporal, em dose unica, e 50 mg/kg divididos em duas tomadas com intervalo de 6 a 8 horas.Oitenta e dois doentes permaneceram internados em uma instituicao de ensino e 53 voltaram para a area endemica apos o tratamento. O controle de cura, em media de seis meses, baseou-se em exames de fezes, pelos metodos de Kato-Katz, Hoffman, Pons & Janer e ecdise.Com a dose de 1 x 30 mg/kg as porcentagens de cura para os grupos I, II e III foram,respectivamente, 53,3%, 26,6%, 20%, com a de 1 x 40 mg/kg 66,7%, 60% e 46,7% e com a de 2 x 25 mg/kg 86,7%, 73,3% e 46,7%. A tolerancia foi excelente em 19 pacientes, boa em 78, regular em 37 e ruim em um paciente. As queixas mais frequentes foram dor abdominal e diarreia. Em se considerando essa nova experiencia,concluimos que o praziquantel e uma boa droga para o tratamento da esquistossomose mansoni