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Biomedical subjects

J Torresani

Publications and source records attributed to J Torresani.

At least 217 records · Page 12Linked to original sources
PubMedDate not supplied

Thyroid hormone binding to plasma membrane preparations: studies in different thyroid states and tissues.

Two orders of high-affinity saturable binding sites for L-T4 and L-T3 were evidenced in purified plasma membrane preparations from rat liver (apparent equilibrium dissociation constant KD for T4 congruent to 0.6 and 23 nM, for T3 congruent to 9 and 237 nM) and kidney (KD for T4 congruent to 4 and 127 nM; for T3 congruent to 15 and 270 nM). Differences of statistical significance were only found for the higher affinity T4 binding site. In contrast, no saturable T4 or T3 binding could be detected in spleen plasma membranes. Testis plasma membranes exhibited 2 sets of T4 binding sites but with a lower affinity than in liver and kidney (KD congruent to 28 and 286 nM), and only one set of T3 binding sites (KD congruent to 266 nM). A good correlation was found between the plasmalemma T4 and T3 binding properties of a tissue and its ability to respond to and/or metabolize thyroid hormones. T4 and T3 binding was also examined in liver plasma membranes of rats under various thyroid status; no difference could be detected in either KD or total capacity for both sets of T4 and T3 binding sites when comparing normal with hyper- or hypothyroid rats. The distribution of plasmalemma high-affinity specific T4 and T3 binding sites in different tissues suggests that these sites are involved in hormone action, or in the transport of these hormones within the cell.

Animals↗
PubMedDate not supplied

Action of beta-adrenoceptor blocking agents on hemodynamic variables and on baroreceptor and postganglionic sympathetic activities in rabbits.

Fifty-six experiments were performed in rabbits anesthetized by urethane or sodium pentobarbital. Baroreceptor (aortic nerve) and post-ganglionic sympathetic (renal nerve) activities were recorded, and peripheral resistances were determined after infusion of beta-adrenoceptor blocking agents (propranolol, pindolol, timolol). A progressive vasodilation was observed after the onset of infusion of the 3 drugs; at the same time arterial pressure decreased, but aortic flow did not vary significantly. Baroreceptor activity was enhanced, whereas efferent renal nerve activity was decreased.

Action Potentials↗
PubMedDate not supplied

Experimental and clinical pharmacology of bretylium tosylate in acute myocardial infarction: a 15-year journey.

Experimental and clinical studies demonstrate the antifibrillatory effectiveness of bretylium tosylate: Experimental ventricular fibrillation induced either by electrical stimulation or by ischemia is prevented by bretylium. In 2,000 acute myocardial infarction patients who received bretylium prophylactically primary ventricular fibrillation occurred in less than 1% of cases. In a randomized hemodynamic study in acute myocardial infarction patients bretylium induced a significant decrease in heart rate, systolic and mean left ventricular pressures, and in systolic and mean aortic pressures. In addition, a parallel and significant decrease in total pulmonary and systemic resistances was seen, accompanied by decreases in tension time and left ventricular (delta P/delta V) indexes. Bretylium tosylate induces stabilization of electrical systole duration (QTc) in acute myocardial infarction patients. The conclusions of the present review strongly support those of the United States Food and Drug Administration, approving bretylium for prophylaxis and treatment of ventricular fibrillation.

Animals↗