Masako Oya Masuda

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1. A voltage clamp has been developed for the pharyngeal muscle of the nematode Ascaris lumbricoides and has been used to analyse the potassium current that produces a negative-going, regenerative action potential in this muscle. 2. Depolarizing voltage steps elicit a sustained inward current; returning the membrane voltage to the resting level evokes a(More)
We propose a protocol for determination of lactate threshold (LT) and test the validity of one aerobic training based on LT in rats. In group I, V(LTi) (velocity at LT before training) was determined in all rats (n=10), each rat training at its own V(LTi) and in group II, animals (n=7) ran at 15 m min(-1), the mean V(LTi) of group I. The training consisted(More)
In humans, there is a significant decrease in serum T(3) and increase in rT(3) at different time points after myocardial infarction, whereas serum TSH and T(4) remain unaltered. We report here a time course study of pituitary-thyroid function and thyroid hormone metabolism in rats subjected to myocardial infarction by left coronary ligation (INF). INF- and(More)
To date no published data exist regarding the effects of chronic high-dose anabolic-androgenic steroid administration on tonic cardiac autonomic control. The aim of this study was to evaluate, by power spectral analysis of heart rate variability (HRV), the effects of chronic treatment with supraphysiological doses of nandrolone decanoate (DECA) on tonic(More)
OBJECTIVES Antibodies against cardiac G protein-coupled receptors have been reported in sera from chronic chagasic patients (CChP) and other non-parasitic cardiomyopathies, but the effects and underlying mechanism of interaction between these antibodies and heart cells are not fully established. To address this point, binding of antibodies purified from(More)
The beneficial effects of exercise in reducing the incidence of cardiovascular diseases are well known and the abuse of anabolic androgenic steroids (AAS) has been associated to cardiovascular disorders. Previous studies showed that heart protection to ischemic events would be mediated by increasing the antioxidant enzyme activities. Here, we investigated(More)
Trypanosoma cruzi infection induces diverse alterations in immunocompetent cells and organs, myocarditis and congestive heart failure. However, the physiological network of disturbances imposed by the infection has not been addressed thoroughly. Regarding myocarditis induced by the infection, we observed in our previous work that Fas-L-/- mice (gld/gld)(More)
Trypanosoma cruzi, the protozoan responsible for Chagas disease, employs distinct strategies to invade mammalian host cells. In the present work we investigated the participation of calcium ions on the invasion process using primary cultures of embryonic mice cardiomyocytes which exhibit spontaneous contraction in vitro. Using Fura 2-AM we found that T.(More)
Primary cell cultures of mouse ventricular myocardium were infected with Trypanosoma cruzi, to study the consequences of T. cruzi-muscle cell interaction on the rate of spontaneous contractions, on the responses to norepinephrine, and on action potential parameters. Single cells or small cell groups of infected cultures were subjected to pharmacological and(More)
Postinfarct congestive heart failure is one of the leading causes of morbidity and mortality in developed and developing countries. The main purpose of this study was to investigate whether transplantation of bone marrow stromal cells (BMSC) directly into the myocardium could improve the performance of healed infarcted rat hearts. Cell culture medium with(More)