PURPOSE The purpose of present study was to investigate the effect of metabolic substrate pyruvate and beta-adrenergic agonist isoproterenol and combination of these agents on the force- and relaxation-frequency relationship in human heart failure. MATERIAL AND METHODS The experiments were performed on isolated human ventricle strips from patients undergoing cardiac corrective open heart surg...

Perfusion of beating false tendons of the dog heart with ionic lanthanum produced drastic but reversible modifications of the excitability and the transmembrane action potential of Purkinje cells. Ultrastructural examination of these cells revealed the appearance of a fine extracellular precipitate detectable on unstained sections. In addition, specimens perfused with La(+++) showed a striking ...

The crude venom of Bothrops jararacussu (Bjssu) is known to induce muscular paralysis in vitro. Many studies have shown that various substances, including heparin, neutralize the damage caused by snake venom. In the present study, the ability of heparin (Hep) and commercial bothropic antivenom (CBA) to neutralize neuromuscular effects of Bjssu venom, at different time-points, was analyzed. Mous...

We developed a new technique of "ice mapping" to localize the site of termination of ventricular tachycardia in dogs 4 to 8 days after the onset of myocardial infarction. During programmed stimulation-induced ventricular tachycardia, the epicardium was mapped by moving an ice probe with a 1 cm tip over the infarct, lateral border, and normal areas. In 31 of 46 morphologically distinct sustained...

Methods were developed for a study of the relations existing between viruses and living cells. It was found that vaccinia and the virus causing the infectious fibroma of rabbits (Shope) rapidly become fixed upon tissue cells freed as individuals and submitted to virus in suspension. This happens whether the cells are alive or have been killed with heat or ultraviolet light. The virus does not c...

A range of pesticides is widely used in pest management and the chances of exposure to multiple organophosphorus (OP) compounds simultaneously are high, especially from dietary and other sources. Although health hazards of individual OP insecticides have been relatively well characterized, there is lesser information on the interactive toxicity of multiple OP insecticides. The aim of this study...

In vitro fertilization assays were performed to investigate their validity in evaluating artificial insemination (AI) bull fertility. A total of 1,532 oocytes, collected from ovaries at the abattoir, were subsequently used in a 4 x 6 x 2 factorial design: 4 doses of heparin added into the capacitation and fertilization medium (0; 0.05; 0.1 and 0.2 micrograms/ml), 6 different bulls with known on...

We studied the effects of nitric oxide (NO) released by NO donors on cat carotid body (CB) chemosensory activity during normoxia and hypoxia. CBs excised from pentobarbital sodium-anaesthetized cats were perfused with Tyrode at 38 degrees C and pH 7.40. The frequency of chemosensory discharges (f(x)) was recorded from the carotid sinus nerve, and changes of NO concentration were measured by a c...

The aim of this study was to investigate the effect of aerial parts of Stachys lavandulifolia Vahl. extract on the rat ileum contractions. The crude extract was prepared by maceration method (90% methanol) followed by fractionating into chloroform, ethyl acetate, petroleum ether and water. In adult male Wistar rats, ileum was sectioned and mounted in tissue bath and their contractility was reco...