Masako Oya Masuda

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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)
We report results obtained with sera from 58 chronic chagasic patients that were evaluated for effects on heart rate and atrioventricular (AV) conduction in isolated rabbit hearts and screened for the presence of muscarinic and beta-adrenergic activity. We show that sera from 26 patients decreased heart rate, while 10 increased it and 22 had no effect.(More)
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)
Antibodies of chronic chagasic patients have been shown to interfere with electric and mechanical activities of cardiac embryonic myocytes in culture and with whole mammalian hearts. A mechanism proposed for this effect involves interaction of the antibodies with G-protein-linked membrane receptors, thus leading to activation of beta adrenergic 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)
The present paper summarizes new approaches regarding the progress done to the understanding of the interaction of Trypanosoma cruzi-cardiomyocytes. Mannose receptors localized at the surface of heart muscle cell are involved in binding and uptake of the parasite. One of the most striking events in the parasite-heart muscle cells interaction is the(More)
AIMS The aim of this study was to investigate whether the sera from chronic chagasic patients (CChPs) with beta-1 adrenergic activity (Ab-beta) can modulate ventricular repolarization. Beta-adrenergic activity has been described in CChP. It increases the L-type calcium current and heart rate in isolated hearts, but its effects on ventricular repolarization(More)
Strips of rabbit atrium 2-3 mm wide and 10-12 mm long were used to study how normal propagating action potentials excite a region where slow responses are the only form of electrical activity. One end of the preparation was bathed in normal Tyrode's solution. The rest was exposed to Tyrode's solution with high K+ (12.7 mM) and Ba++ (1 mM) (TKBa solution).(More)
Outward current oscillations associated with transient membrane hyperpolarizations were induced in murine macrophage polykaryons by membrane depolarization in the absence of external Na+. Oscillations corresponded to a cyclic activation of Ca(2+)-dependent K+ currents (IKCa) probably correlated with variations in intracellular Ca2+ concentration. Addition(More)
1. We investigated Na(+)-Ca2+ exchange and the involvement of the sarcoplasmic reticulum in frequency-dependent slow response excitability enhancement in rabbit atrial trabeculae. 2. Slow responses were induced in a modified Tyrode solution containing high K+ and Ba2+ and conventional electrophysiological techniques were used for stimulating and recording(More)