IntroductionChagas disease is one of the most important endemic parasitic diseases in Latin America. In its chronic phase, progression to cardiomyopathy has high morbidity and mortality. The persistence of a normal electrocardiogram (ECG) provides a similar prognosis to that of a non-diseased population. Benznidazole (BNZ) is the only drug with trypanocidal action available in Brazil.Materials/Methods/ResultsA group of 310 patients with chronic Chagas disease who had normal ECGs at the first medical visit performed before 2002 were included. There were 263 patients treated with BNZ and 47 untreated. The follow-up period was 19.59 years. Univariate analyses showed that those treated were younger and predominantly male. As many as 79.08% of those treated and 46.81% of those untreated continued with normal electrocardiograms (p <0.0001). The occurrence of electrocardiographic abnormalities and relevant clinical events (heart failure, stroke, total mortality, and cardiovascular death) was less prevalent in treated patients (p <0.001, p: 0.022, p: 0.047 respectively). In multivariate analyses, the parasiticide treatment was an independent variable for persistence of a normal ECG pattern, which was an independent variable in the prevention of significant clinical events. The immunofluorescence titers decreased with the parasitological treatment. However, the small number of tests in untreated patients did not allow the correlation of the decrease of these titers with electrocardiographic alterations.ConclusionThese data suggest that treatment with benznidazole prevents the occurrence of electrocardiographic alterations. On the other hand, patients who develop ECG abnormalities present with more significant clinical events.

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Benznidazole and amiodarone were equally effective in eliminating T. cruzi in culture. The combination of the two drugs was also equally effective, but our data cannot demonstrate synergism, as similar results were obtained when the drugs were tested individually or in combination. It is suggested that this study be repeated with other T. cruzi strains to determine whether similar results can be obtained again.

SummaryBackground: The effects of aging on papillary muscle have been widely demonstrated, but no data on the effects of exercise on the age-related changes are available.

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Introduction: Chagas’ disease lacks elements to predict which carriers will evolve into cardiac form and which will remain in undetermined form. Objective: To evaluate the relationship between electrocardiographic evolution and Tpeak–Tend and QT intervals, both corrected for heart rate, in chagasic patients with normal initial electrocardiogram. Method: Chagasic patients admitted to the institution until 2002 were retrospectively evaluated, and the electrocardiogram was normal at the first consultation. The Tpeak–Tend and QT intervals were measured in milliseconds at the V2 and V5 derivations, with the mean values corrected for heart rate (Bazett). The relationship of these values with the electrocardiographic evolution of the individuals was analyzed, considering the gender, time of evolution and whether they received benznidazole or not. Results: The corrected Tpeak–Tend interval showed no statistical significance among those who maintained or not normal electrocardiogram. The corrected QT interval, the treatment with benznidazole and the time of evolution showed significance for the maintenance of normal electrocardiogram. In the multivariate evaluation, treatment with benznidazole, the QTc interval and the time of evolution were independent variables for the maintenance of normal electrocardiogram. Conclusion: The Tpeak–Tend interval showed no predictor of electrocardiographic evolution. The increased QT interval favored changes.

BackgroundThe effects of extracellular dehydration on the urinary bladder reactivity.AimTo investigate if different extracellular dehydration models affect urinary bladder reactivity to vasopressin and neurotransmitters of the autonomic nervous system in female Wistar rats.MethodsAdult female Wistar rats (N=6/group) one group the animals were in water deprivation for 24 hours and another group received a furosemide injection (50,0 mg/Kg S.C) and were maintained with sodium free diet. After all animals were anesthetized with 2% isoflurane in 100% O2 underwent to a cannulation of the femoral artery for mean arterial pressure and heart rate recordings. The urinary bladder was cannulated for intravesical pressure (IP) recordings. After baseline recording of the physiological parameters for 15 min, drugs (vasopressin 1 ng/mL, or acetylcholine 2 ug/mL, or noradrenaline 2 ug/mL) were administrated in situ (0.1 mL) on the urinary bladder and all the parameters were recorded for the control responses The AVP receptor subtypes were also labeled by immunofluorescence technique in the urinary bladder. Data are as mean±SE and were submitted to paired Student t‐test (p<0.001).ResultsThe water privation group responses in IP to vasopressin (39,5±1,0% vs. 110,1±1,9% control), acetylcholine (125,9±12,4% vs. 488,8±24,9% control), and noradrenaline (−17,5±1,0% vs. −67,6±1,6% control) were attenuated. Similarly the furosemide group the IP responses to vasopressin (42,8±2,8% vs. 110,1±1,9% control), acetylcholine (145,0±5,0% vs. 488,8±24,9% control), and noradrenaline (−28,8±1,0% vs. −67,6±1,6% control)were reduced. The immunofluorescence was showed a decrease in the amount of vasopressin receptors on the membrane of urinary bladder cells after dehydration in both models.ConclusionBoth models decreased the urinary bladder reactivity to vasopressin and to the neurotransmitters released by the autonomic nervous system innervation on the urinary bladder.Support or Funding InformationFinancial Support: FAPESP, CAPES and NEPAS.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Introdução: A doença de Chagas carece de elementos que proporcionem prever quais portadores evoluirão para a forma cardíaca e quais permanecerão na forma indeterminada. Objetivo:Avaliar relação entre evolução eletrocardiográfica e intervalos Tpico–Tfim e QT, ambos corrigidos para a frequência cardíaca, em chagásicos com eletrocardiograma inicial normal. Método: Avaliamos retrospectivamente chagásicos admitidos na instituição até 2002, tendo eletrocardiograma normal na primeira consulta. Os intervalos Tpico–Tfim e QT foram medidos em milissegundos nas derivações V2 e V5, sendo a média dos valores corrigida para a frequência cardíaca (Bazett). Analisou-se a relação desses valores com a evolução eletrocardiográfica dos indivíduos, tendo em vista sexo, tempo de evolução e se receberam benzonidazol ou não. Resultados: O intervalo Tpico–Tfim corrigido não mostrou significância estatística entre os que mantiveram ou não eletrocardiograma normal. O intervalo QT corrigido, o tratamento com benzonidazol e o tempo de evolução mostraram significância quanto à manutenção do eletrocardiograma normal. Na avaliação multivariada, o tratamento com benzonidazol, o intervalo QTc e o tempo de evolução se mostraram variáveis independentes para a manutenção do eletrocardiograma normal. Conclusão:O intervalo Tpico–Tfim não se mostrou preditor da evolução eletrocardiográfica. O intervalo QT aumentado favoreceu aparecimento de alterações.