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Biomedical subjects

I S Chekman

Publications and source records attributed to I S Chekman.

At least 37 records · Page 2Linked to original sources
PubMed1985

[Interaction of beta-adrenergic agents with the plasma membranes of the myocardium].

The initial stage of interaction of beta-adrenomimetics and beta-adrenoblockers with specific membrane binding sites is characterized by different patterns of thermodynamic parameters. Administration of isadrin results in a decrease of entropy and enthalpy, which reflects the primary binding reaction and agonist-specific receptor isomerization to the conformational form activating adenylate cyclase. Anaprilin and alpheprol do not change the receptor conformation and participate only in the primary binding reaction which is marked by a decrease in enthalpy and a rise of entropy in the course of interaction of beta-adrenoblockers with specific membrane binding sites. The different patterns of thermodynamic parameters under the effect of beta-adrenomimetics and beta-adrenoblockers on plasma membranes are explained by the different influence of these substances on the mobility of membrane lipids, i.e. on the viscosity of plasma membranes.

Adrenergic beta-Antagonists↗
PubMed1985

[Inotropic effect of strophanthin in combination with calcium on the heart muscle].

The effect of strophanthine-g and its combination with different concentrations of calcium in Tyrode solution was studied in guinea-pig auriculi atrii contracting under the effect of isometric electric stimulation. Addition to Tyrode solution of strophanthine-g combined with calcium promoted the reduction of the positive inotropic effect of the former substance. During perfusion of the muscles with Tyrode solutions containing no calcium, the maintenance of the contractile function of the muscles is secured adequately enough by addition of strophanthine-g combined with low concentrations of calcium. Combinations of the cardiosteroid and calcium calculated on the basis of the stability constants of their complexes appeared effective. It is inferred that cardiosteroids should be combined with small amounts of calcium in order to attain a positive inotropic effect.

Animals↗
PubMed1985

[Changes in the energy resources of rat gastric mucosa exposed to dopamine agonists and antagonists in conditions of experimental stress].

Changes in adenyl nucleotide and glycogen content in rat gastric tissue under the action of stressogenic factor and injection of the dopamine blocker metoclopramide and the dopamine precursor L-DOPA were investigated with the use of the "social stress" method devised by the authors. It was established that stress induced gastric mucosal lesions and reduced the content of adenyl nucleotides and glycogen in the gastric tissue. Preliminary injection of L-DOPA potentiated the effect of stress while metoclopramide inhibited it. The data show a role of energy balance disturbances in the gastric tissue in the pathogenesis of an acute ulcer. In the authors' opinion, the disturbances seen during immobilization psychogenic stress were caused by undue stimulation of central dopamine receptors.

Animals↗
PubMed1977

[Effect of dipyroxime on the concentration of nicotinamide coenzymes and adenylate nucleotides in the myocardium and liver of rats poisoned with phthalophos].

Experiments were conducted on rats; in depression of blood cholinesterase activity by 68.6 percent phthalafos proved to decrease the myocardial nicotinamide coenzymes content on account of reduction in the amount of the oxidized forms. In the liver phthalafos diminished the content of oxidized and reduced forms of nicotinamide coenzymes, decreased the level of adenylic nucleotides chiefly at the expense of ATP. Diproxim prevented the changes caused by phthalafos in blood cholinesterase reactivation to 47.5 percent. It is supposed that the capacity of diproxim to normalize the oxidative processes in the cell by acting upon the nicotinamide coenzymes and adenylic nucleotides underlies its antidote action.

Animals↗
PubMed1976

[Changes of catecholamine content in the myocardium in thyrotoxicosis].

Experimental thyrotoxicosis was induced in rats and rabbits. The content of catecholamines was significantly decreasing in the myocardium of rabbits in the presence of severe thyroidine-induced toxicosis. The noradrenaline concentration was especially low in the ventricles. The histochemical examination of the myocardium of rats revealed a reduction of catecholamines fluorescence, which indicates a decrease in their amount in the adrenergic structures.

Animals↗
PubMed1975

[Level of nicotinamide coenzymes in the liver and myocardium of rats poisoned with dichlorethane].

Experiments were conducted on male rats. A study was made of the content of nicotinamide coenzymes in the liver and myocardium 24 hours after the administration of 0.5 ml of dichloroethane into the stomach. In parallel with disturbance of the morphological structure of the liver and of the myocardium, increase in the activity of alanine and aspargic aminotranspherases in the blood serum, dichloroethane reduced the content of nicotinamide coenzymes and deranged the ratio of their oxidized and reduced forms in these organs.

Alanine Transaminase↗