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G F Dvortsin

Publications and source records attributed to G F Dvortsin.

At least 19 recordsLinked to original sources
PubMed1991

[Anti-stress effect of dalargin in immobilization stress in rats].

The function of the isolated perfused rat hearts was studied in four groups of experiments. Group 1--included the hearts of intact animals ("absolute control"), group 2--the hearts of rats subjected to 24 hour immobilization in supine position against the background of triple intramuscular injections of placebo (control), group 3 included the hearts of rats, which during 24 hour immobilization stress were thrice injected a synthetic analogue of endogenous opioids Dalargin in a dose of 3 g/kg, and group 4 included the hearts of animals, which during immobilization were administered Dalargin in a dose of 10 g/kg of body mass. Ulcer index as indicator of stress injury of gastric mucosa was also determined. In the control group of experiments (group 2) 24 hour immobilization stress resulted in complete depression of cardiac performance as compared with group 1, and ulcer index approximated 1. In group 3 the indices of cardiac performance even exceeded those in group 1 (intact animals). As compared with group 2, ulcer index in group 3 decreased by 9 times. In application of Dalargin in a dose of 10 g/kg complete preservation of heart function indices and complete prevention of stress injury of gastric mucosa were also observed. Thus, Dalargin possesses cardioprotective and anti-ulcerogenic effect in immobilization stress in rats. Most probably, this phenomenon can be attributed to its ability to inhibit the activity of sympathoadrenal system, which gets enhanced during stress.

Animals↗
PubMed1989

[Use of a synthetic opioid for the reversal of stress-induced damage of the myocardium and gastric mucosa in severe thermal trauma].

Three series of experiments were performed in Wistar male rats. The first series covered the study of the function of isolated perfused hearts and the status of the gastric mucosa in intact animals. In series II and III, Stages IIIB-IV contact burn of 25% body surface was induced by a special device. The animals were observed for 24 hours. Following 23.5 hours of burn, the rats were injected placebo (Series II) or the synthetic Leu-enkephalin analogue dalargin, 10 micrograms/kg in the same amounts as placebo (Series III). After observation, the animals' hearts and stomachs were isolated and explored. In Series II, there was a considerable decrease in all the indices of cardiac function as compared to the controls, the ulcer index that characterizes the severity of stress-induced gastric mucosa injury was found to be 8.2. In Series III, the indices of cardiac function were even substantially higher than those in intact animals, the ulcer index was reduced to 0.01. Thus, dalargin, a Soviet synthetic Leu-enkephalin analogue, possesses marked anti-stress and cardioprotective effects in severe thermal trauma. The paper also considers the likely mechanisms responsible for the phenomena observed.

Animals↗
PubMed1989

[Increasing myocardial tolerance of global ischemia and reperfusion injury using a synthetic peptide].

The synthetic tripeptide Tyr-Pro-Arg was tested for its cardioprotective effect when added to the cardioplegic solution or when used during reperfusion (R) after "global myocardial ischemia" (GMI). After the baseline functional parameters had been recorded, the isolated perfused hearts (IPH) from rats with the working left ventricle were subjected to 30-minute GMI at 37 degrees C. When the tripeptide was added to the cardioplegic solution (3.10(-9) M), the degree of the functional recovery of IPH was higher after GMI than when a "pure" cardioplegic solution was applied. The functional parameters of IPH were restored to a considerable extent (up to 70-100%) when the tripeptide was added to the perfusate in the same concentration during R following GMI of 30-minute duration at 37 degrees C. Without the tripeptide, the function of IPH was not restored. Thus, the synthetic analogue of the endogenous opioids, Tyr-Pro-Arg" enhances the tolerance of rat IPH myocardium to exposure to GMI and R.

Animals↗
PubMed1986

[Electrophysiological study of the cardiotropic action of phenothiazine-derivative anti-arrhythmia preparations].

Cardiotropic action of antiarrhythmic agents etmozin and etacizin, phenothiazine derivatives, was studied electrophysiologically in 42 mongrel dogs (using isolated heart and intact body models). Etmozin produced no direct effect on sinus node function, whereas etacizin suppressed it in isolated hearts. Etmozin and etacizin significantly affected the atrial, atrioventricular-node and His-Purkinje conduction time, having no basic effect on the duration of respective refractory periods. Therefore, they can be referred to antiarrhythmic agents, group 1, subclass C. The magnitude and pattern of etmozin-and etacizin-induced electrophysiologic changes in the isolated heart and the integrated system are basically similar, an evidence of cardiotropic effects of these drugs. The model of an isolated dog heart perfused by a donor dog's blood can be used for the assessment of cardiotropic effects of drugs in preclinical trials of new antiarrhythmic agents.

Animals↗
PubMed1982

[Changes in the electrical activity and coronary blood flow of a heterotopic heart allograft during a graft rejection crisis].

In 12 experiments on dogs heterotopic cardiac allotransplantation on the recipient's neck has been performed. During the transplant survival its electrical activity and the coronary blood flow (CBF) were recorded with an implanted sensor of electromagnetic flowmeter. The combination of relatively low CBF and the amplitude of R wave during the first hours after transplantation with a high heart rate is a poor prognostic sign. Oscillations of CBF run parallel to changes of ECG when the viability of the transplant is retained, during the rejection crisis these changes do not correlate. The significance of comprehensive assessment of the cardiac function with the use of ECG and CBF measurement and comparison of their absolute figures and dynamics is shown to be of importance for the early diagnosis of the rejection crisis.

Animals↗
PubMed1982

[Improved method of perfusion and functional loading of the isolated heart. Studies as a control and following cardioplegia].

The authors have elaborated and studied in 52 experiments an improved method of donor perfusion of an isolated dog heart. The technique of removing the heart without ischaemia and after cardioplegia as well as the technique of perfusion of the arrested and the contracting heart are described. The authors used their own method of the functional load testing of the left ventricle after cardioplegia. The function of the isolated dog heart without ischaemia was studied in control experiments. The advantages of the described method of perfusion and functional load of an isolated heart are: it is manageable, physiological and easily reproduced. The method can be used in experimental cardiology.

Animals↗
PubMed1980

[Effect of different doses and administration conditions of propranolol on heart function and hemodynamics].

It was demonstrated in 12 dog experiments with the use of electromagnetic flowmetry and an automatic system of heart function analysis that a single intravenous injection of propranolol in a dose of 0.1 +/- 0.017 mg/kg causes a negative chrono- and inotropic effect and a moderate hypotensive effect in negligible change in the cardiac output. Repeated injections of propranolol in doses of 0.05 mg/kg to a final dose of 0.2 mg/kg at intervals of 5 min (total dose of 0.4 mg/kg) are not attended by increasing inhibition of cardiac function. In systolic and volume load after intravenous injection of propranolol in a dose of up to 0.4 mg/kg it was found that the heart was capable of providing quite adequate hemodynamics. The features of the regulation of cardiac function under these conditions were determined.

Animals↗
PubMed1979

Homologous blood syndrome in dogs. Effect of erythrocyte and platelet antibodies.

Isovolemic perfusion of 50% of the recipient circulating blood volume was carried out in intact mongrel dogs using whole donor blood as well as plasma or platelet suspensions in saline. Perfusion against the background of circulating red blood cells (RBC) or platelets antibodies in the donor or in the recipient was followed by severe and sometimes fatal homologous blood syndrome in a majority of the dogs. Weak and short-term reactions were seen in a few dogs if red blood cells and platelet antibodies were absent.

Animals↗
PubMed1976

[Experimental basis of a new method of determination of coronary blood flow with the aid of electromagnetic flowmeter].

Canine experiments have demonstrated the high precision of measurements performed with the aid of modern electromagnetic flowmeters (1-2%). Under such conditions, cuff transducers of a large diameter permit to record low volume flow rates. Proceeding from this observations, the authors have introduced and experimentally substantiated a new method of measuring the coronary blood flow that consists in the determination of the minute volume gradient between the pulmonary artery trunk and the ascending aorta. In contrast to the existing techniques of coronary flow measurements, the introduced method has several advantages (it takes into account the total coronary flow, permits high precision and an unlimited number of repeated measurements in a dynamic observation), but it can be employed only in the course of surgical interventions on the heart after the ascending aorta has been separated from the trunk of the pulmonary artery.

Animals↗
PubMedDate not supplied

[The cardioprotective effect of a new Soviet synthetic analog of the endogenous opioids in stress due to total myocardial ischemia and its mechanisms].

It was demonstrated in experiments on male Wistar rats that preliminary use of a perfusion liquid containing the synthetic tripeptide Tyr-Pro-Arg facilitates restoration of the indices of the function of isolated perfused hearts (IPH) of rats after stress caused by 30-minute total ischemia (TI) of the myocardium at 37 degrees C. Irreversible damages to the myocardium and total depression of its function were recorded in the controls in this period of TI. The optimal concentration of the preparation in the perfusion fluid providing for restoration of IPH function by 80-100% of the initial level is 3.10(-9) M. The protective effect of the preparation is preserved in preliminary (30 minutes prior to TI) intraintestinal and intragastric administration of 10 micrograms/kg. Administration of Tyr-Pro-Arg separately or together with the beta-blocking agent propranolol as well as with atropine, which blocks the vagus effect, revealed their concurrent relations at the level of the adrenergic receptors. It is concluded that the cardioprotective effect of Tyr-Pro-Arg in TI stress is determined to a great measure by its inhibiting effect on the adrenergic mechanisms of cardiac activity regulation. Experiments in which the Ca2+ concentration in the perfusion fluid was increased threefold before and after TI showed that after using Tyr-Pro-Arg the IPH function after TI was restored and stimulated sharply by the increased Ca2+ concentration, in contrast to the controls in which stimulation of cardiac activity before TI increased the ischemic damage to the myocardium.

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