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Biomedical subjects

E B Novikova

Publications and source records attributed to E B Novikova.

At least 19 recordsLinked to original sources

[Experimental and clinical studies of coronary circulation after administration of mildronate].

In experiments on dogs, application of the cross-over circulation method revealed that mildronate increased coronary blood flow due to active coronary dilation. In experiments on cats, a cardioprotective effect of mildronate was found, which prevented the development of acute ischemic heart failure by stabilizing the major hemodynamic parameters. Clinical studies of patients with Functional Classes I-III angina provided evidence for positive effects of mildronate on coronary blood flow.

Adult↗

[Effect of a decrease in perfusion pressure on the alpha-adrenergic reactions of the coronary vessels].

Acute dog experiments involving the perfusion of donor coronary arteries demonstrated that alpha-adrenoreceptor stimulation in the presence of a beta-adrenergic block resulted in a 30% drop of coronary flow. This response is maintained at low perfusion coronary blood pressure values (up to 25 +/- 13 mmHg, p less than 0.02), whereas coronary dilatation reserve is already fully depleted at 60 +/- 8 mmHg, suggesting that the degree of coronary arterial stenosis associated with coronary insufficiency may be a decisive factor shaping coronary response to alpha-adrenoreceptor stimulation.

Animals↗

Function and metabolism of dog heart in ischemia and in subsequent reperfusion: effect of exogenous glutamic acid.

The effect of intravenous infusion of glutamic acid on cardiac contractile function during short-term ischemia and subsequent reperfusion was studied in anaesthetized dogs. Left ventricular ischemia was induced by underperfusion of the anterior descending and circumflex coronary arteries. Infusion of glutamic acid at 3 mg/kg/min resulted in less depression of cardiac function when given after a 2 min period of 60% coronary blood flow reduction: left ventricular systolic pressure decreased by 9% vs. 22%, dP/dt decreased by 16% vs. 29%, the double product (left ventricular systolic pressure by heart rate) was reduced by 16% vs. 31%. When reperfusion was carried out during glutamic acid infusion there was a significantly enhanced recovery in cardiac function. The augmentation of cardiac performance in ischemia and reperfusion caused by glutamic acid was not accompanied by changes in myocardial oxygen consumption. Glutamic acid uptake by the ischemic myocardium increased 2-fold during infusion. This led to cessation of ammonia release from the heart due to stimulation of glutamine synthesis, and an enhancement of alanine formation coupled with pyruvate uptake but it did not effect lactate production. However, glutamic acid infusion did not influence cardiac performance and metabolism under conditions of normal coronary flow. The results suggest that elevation of glutamate arterial concentration exerts a beneficial effect on ischemic heart. The mechanisms of the protective action are discussed.

Alanine↗

[Correction of contractile function and metabolism in canine ischemic myocardium due to exogenous glutamic acid].

The effect of intravenous glutamic acid infusion (3 mg/kg/min) was studied during myocardial ischemia and reperfusion in anesthetized dogs. Left ventricular ischemia was induced by underperfusion of the anterior descending and circumflex coronary arteries. Glutamic acid reduced the ischemic contractile depression 2 min after a 60%-reduction of the coronary blood flow. The left ventricular systolic pressure was decreased by 9% versus 22%, dP/dt by 16% versus 29%, left ventricular systolic pressure heart rate product by 16% versus 31%. Reperfusion with glutamic acid improved the recovery of cardiac performance without any increase in myocardial oxygen consumption. Glutamic acid infusion resulted in a 2-fold augmentation of glutamate uptake by the ischemic myocardium. It led to cessation of ammonia release by the heart due to activation of glutamine synthesis, enhancement of alanine formation coupled with pyruvate utilization and did not change lactate production. The mechanisms of the protective action of glutamic acid are discussed.

Alanine↗

Changes in coronary blood flow produced by the coronary artery occlusion.

The influence of the occlusion of one coronary artery on coronary blood flow in an intact myocardium was investigated in narcotised dogs with open chest by using the crossed circulation method. Interruption of blood inflow to one of the branches of the left coronary artery under autoperfusion of the coronary bed led to a drop in the blood flow rate in the intact branch of the same artery, which was caused by decreased perfusion pressure. Stabilization of coronary perfusion pressure made it possible to detect the dilatatory reaction of the intact coronary bed to the occlusion of one of the coronary arteries. On the basis of an analysis of the dilatatory reaction, conclusions are drawn about the reflex nature of the observed phenomenon. The results of experiments with selective pharmacological blockade of both parts of the autonomous nervous system suggest that the afferent and efferent pathways run in the sympathetic nervous system.

Afferent Pathways↗

[Role of oxygen extraction from coronary blood in the regulation of oxygen transport to the myocardium].

Experiments on anesthetized dogs were made to examine oxygen extraction from coronary blood during increase and decrease in cardiac rhythm frequency under varying conditions of vasomotor regulation. With an initially high tone of the coronary vessels both increase and reduction of myocardial oxygen supply occurred at the expense of vasomotor reactions. Under these conditions the coronary blood flow velocity and systolic rhythm correlated well. At the same time the oxygen level in coronary blood did not experience noticeable changes. As the initial tone of the coronary vessels dropped, vasomotor reactions were attenuated and oxygen extraction from coronary blood underwent alterations which had occurred prior to depletion of the coronary expanding reserves. The data obtained suggest that reduction of the initial tone of the coronary vessels proceeds non-uniformly, leading to a decrease in vascular sensitivity to the tissue oxygen level.

Animals↗

[Certain problems in the autonomic innervation of acupuncture zones of human skin].

Cholinergic and adrenergic components of vegetative innervation in acupuncture zones of the human skin (in acupuncture "points") were studied by the histochemical method for acetylcholine esterase and by the method of luminescent microscopy. Skin samples were obtained by means of biopsy. In 23 corporal acupuncture zones in the skin, cholinergic nerve conductors and terminals were found to be concentrated and structurally connected with multiple vessels of the skin and its derivatives: sweat glands, folliculi of the fluffy hairs and smooth muscles. In the derm, among its derivatives, numerous free varicose axons with a high positive reaction for acetylcholine esterase were found. In 7 out of 9 examined neutral areas of the human skin, a weak cholinergic innervation was revealed. In biopsies obtained from patients during operations, adrenergic nerves in acupuncture zones were found in small amount on the vessels of skin and in smooth muscles. The problem on participation of acetylcholine from the skin neural elements in the mechanism of therapeutic effect of acupuncture is discussed.

Acetylcholinesterase↗