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Biomedical subjects

S F Dugin

Publications and source records attributed to S F Dugin.

36 records · Page 2Linked to original sources
PubMed1987

[Method of radionuclide determination of coronary blood flow: experimental verification and clinical testing].

For quantitative assessment of the coronary blood flow in diagnostic examination of CHD patients the authors have proposed a new method for determination of absolute values of the coronary blood flow by intragastric administration of 99m Tc-labeled human serum albumin microspheres with subsequent whole body scintigraphy and comparison of scintillation count intensity over the heart area and the whole body. The results of experiments on 13 rabbits for verification of the method and the results of clinical testing in 20 patients were presented. The proposed method was shown to ensure adequate assessment of the coronary blood flow in ml/min. the patient's safety without interfering in routine coronary angiographic investigation, providing very important additional diagnostic information. The method was recommended for clinical diagnostic practice in x-ray departments of cardiological hospitals.

Adult↗
PubMed1987

[Various hemodynamic mechanisms of the hypertensive reaction in immobilization-induced stress in rabbits and rats].

The radioactive microsphere technique was used to measure the cardiac output, regional blood flows and resistances in conscious rabbits and rats before and after 30-minute immobilization. Immobilization evoked blood pressure rise in both species. Cardiac output was reduced and total peripheral resistance increased in rabbits. Reverse changes of these parameters were observed in rats. Blood flow was reduced in the liver and the right ventricle in rabbits, and in the testes in rats. In immobilized rats, regional blood flow increased in skeletal muscles, the heart, the adrenals and the liver. These experiments demonstrate different hemodynamic mechanisms of immobilization-induced hypertension in rabbits and rats.

Animals↗
PubMed1986

[Hemodynamic mechanisms of the hypotensive action of the new calcium antagonist foridon in acute hypertension in rabbits. A comparison with nifedipine].

The radioactive microsphere technique was used to study hemodynamic mechanisms of action of 2 calcium antagonists--foridon and nifedipine in conscious rabbits with acute hypertension evoked by immobilization. Microspheres were injected before and 5 min after bolus i.v. injection of equihypotensive (10% blood pressure drop) doses of nifedipine (30 mcg/kg) and foridon (50 mcg/kg). Nifedipine in most cases decreased cardiac index by 7% without significant changes in regional hemodynamic. After foridon injection total peripheral resistance decreased by 19% (P less than 0.05) and cardiac index increased by 18%. There were increase in blood flow: in the heart by 34% (P less than 0.05), in the skeletal muscle by 41% (P less than 0.05) and in testes by 12% (P less than 0.05). The results show that in acute stress-induced hypertension these dihydropyridine-derivatives have different hemodynamic mechanisms of action: nifedipine preferentially depress myocardial contractility, whereas foridon dilates blood vessels.

Acute Disease↗
PubMed1981

[Heart rate regulation during depressor reflexes].

Chronic experiments on cats were made to study the relationship between reflex tachycardia in response to the drug-induced arterial blood pressure fall and spontaneous variations in the initial cardiac rhythm. The existence of inverse linear correlation was shown between the magnitude of chronotropic response and control heart rate before and after beta-adrenergic blockade. The significance of the correlation disclosed for the interpretation of the research data on the relative role of the sympathetic and parasympathetic heart regulation performed in different experimental conditions is discussed.

Animals↗
PubMedDate not supplied

Effects of electrical stimulation of vagal nuclei in anesthetized and unanesthetized cats.

Changes in the heart rate were studied during stimulation of the effector nuclei of the vagus nerves--the dorsal vagal nucleus and the nucleus ambiguus--in anesthetized and unanesthetized cats. If groups of neurons, stimulation of which in anesthetized cats causes slowing of the heart, were stimulated in unanesthetized cats under conditions of free behavior, the heart rate was increased. Pharmacological beta-adrenergic receptor blockade by injection of Obsidan or Inderal (propranolol) demonstrated the parasympathetic nature of these effects. The fact that they are parasympathetic in nature was also confirmed by the character of the response: its short latent period and rapid disappearance of the effect after removal of the stimulation.

Anesthesia, General↗
PubMedDate not supplied

[Comparative study of hemodynamic effects of antidepressants (tetrindole and desipramine) during immobilization stress in hypertensive rats].

Tetrindole (a tetracyclic antidepressant, reversible MAO inhibitor of the A type) and desipramine (a tricyclic antidepressant, nonselective inhibitor of the reverse catecholamine trapping) produce opposite hemodynamic effects in stroke-prone hypertensive rats (SHR-SP): tetrindole reduced, whereas desipramine increased, the heart rate and arterial pressure. Under the acute immobilization stress conditions in SHR-SP, tetrindole inhibited development of the post-stressor tachycardia, while desipramine did not change the heart rate and increased the arterial pressure.

Animals↗
PubMedDate not supplied

[The influence of chronic neurotization on the monoaminergic systems of various brain structures in rats with various typological characteristics].

Typological behavioral features of Wistar rats were tested in the open field and in Porsolt test. Rats were assigned to groups with high (HAct), medium (MAct), and low (LAct) behavioral activities. The same rats were assigned to high (HDep), medium (MDep) and low depressive (LDep) groups. The release of norepinephrine, dopamine, serotonin and their metabolites in homogenates obtained from the hypothalamus, hippocampus, frontal cortex and amygdala was assessed by microdialysis and HPLC. In these groups, the monoamine concentrations were different: the level of serotonin was higher in the hypothalamus and norepinephrine and 5-HIAA levels were lower in the hippocampus of MAct - MDep rats as compared to LAct - HDep. Chronic neurotization caused changes in monoamine concentrations in the hypothalamus and amygdala in rats of all groups, whereas in the hippocampus and frontal cortex monoamine changes were observed in HAct - LDep and LAct -HDep rats. The most prominent changes in monoamines levels in neurotized rats with different types of behavior were found in the frontal cortex, amygdala and hippocampus. The results show a correlation between the typological of behavioral characteristics and the reaction to stress of monoaminergic systems of the hypothalamus, hippocampus, frontal cortex and amygdala.

Amygdala↗
PubMedDate not supplied

[The regulation of systemic and regional hemodynamics in waking rats with a chronic adriamycin-induced myocardial lesion].

Rats were given intraperitoneal injections of adriamycin (cumulative dose 20 mg/kg). Two weeks after the last injection left-ventricular function and systemic and regional hemodynamics were studied before and during isoprenaline infusion (0.64 mcg/kg/min) in conscious rats with no signs of cardiac insufficiency. In the controls isoprenaline increased the left-ventricular contractility index by 45% and the heart rate by 30%. The contractility index in rats given adriamycin did not change, the heart rate increased only by 14%, but in contrast to the controls, a significant increase of the cardiac index by 36% and diminution of total peripheral resistance by 36% were revealed. The sensitivity of the baroreflex chronotropic component in the control animals was twice that in the experimental rats. It is concluded that adriamycin cardiomyopathy in rats is attended by reduced sensitivity of the baroreflex mechanisms and diminished myocardial adrenergic reactivity.

Animals↗
PubMedDate not supplied

[Antifibrillatory effect of the calcium antagonist foridon in acute myocardial ischemia in conscious rabbits].

The effect of ryodipine on disorders of rhythm induced by occlusion of the left descending coronary artery was studied in experiments on 40 conscious immobilized rabbits. Ryodipine was injected intravenously (50 mcg/kg 5 minutes prior to and 25 mcg/kg after occlusion). Ventricular fibrillation developed in 19 (66%) rabbits of the control group and in 3 (27%) animals in the experimental group (p less than 0.03). The parameters of systemic and regional hemodynamics were studied in 7 rabbits of the control group and in 5 animals of the experimental group before and 30 minutes after occlusion; microspheres (15 mcm) labelled with various radioactive isotopes were used in the study. The blood flow in the intact myocardium of rabbits given ryodipine was higher than the initial level by 14% (p less than 0.05). The coronary fraction of the cardiac output increased by 21%. It is concluded that the antifibrillation effect of ryodipine is due to its favourable action on the myocardial blood flow.

Animals↗
PubMedDate not supplied

[Systemic and regional hemodynamics in alert rats with increasing hyperthermia].

The changes in the parameters of systemic and regional hemodynamics during thermal stress were followed up in awake male Wistar rats. The cardiac output (CO) and blood flow in 16 zones of the body were measured by means of 15 microns microspheres labeled by 4 different isotopes. The blood flow increased in the skin of the tail, the liver, heart, adrenals, and skeletal muscles and reduced in the organs of the splanchnic region and kidneys. When body temperature reached 42 degrees C the CO decreased. The shifts in the regional blood flow maintained their direction, with the exception of a sharp increase of blood flow in the small intestine which preceded or coincided with the beginning of a fall in arterial pressure. The rate of increase of left ventricular pressure remained at a high level. It is assumed that the disruption of celiac vasoconstriction is among the earlier developing links of hemodynamic disorders in thermal affections and is caused by the vasodilative effect of the factors of local control of the vascular functions.

Animals↗