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Biomedical subjects

G Pogátsa

Publications and source records attributed to G Pogátsa.

At least 73 records · Page 4Linked to original sources
PubMed1982

The role of the myocardial water content in heart function.

In previous experiments a considerable interstitial oedema developed after myocardial infarction followed by the infusion of 6 mmol/kg/min norepinephrine lasting for 10 min in the 2nd and 48th hours as well as after a 60 min period of ventricular fibrillation during cardiopulmonary bypass. On the other hand myocardial dehydration was induced by hyperosmolality of 320-470 mOsm/l caused by mannitol or glucose after pancreatectomy. A close bilinear correlation was found between the myocardial water content and the increase of ventricular diastolic stiffness. It was further established that the increase of ventricular stiffness is followed by a decrease of the cardiac output index measured during left ventricular afterload. The cardiac output index was lower after myocardial infarction and pancreatectomy than during cardiopulmonary bypass or mannitol-treatment. Of clinical importance is the fact that ventricular performance decreases when myocardial water content exceeds or does not reach the value of 760-790 g water per 1000 g myocardium.

Animals↗
PubMed1982

Effects of prostaglandins E2, I2 and F2 alpha on the tone of isolated coronary arteries from alloxan-diabetic dogs.

Contractile responses to PGF2 alpha of isolated coronary arteries from 7 healthy and 12 alloxan-diabetic dogs without ketosis were considerably increased by indomethacin and decreased by PGI2. The increasing effect of indomethacin was more prominent on diabetic vessels than on those of normal animals while PGI2 had the same relaxant potency in both groups. The contractions induced by PGF2 alpha were inhibited more effectively by PGI2 than those evoked by PGE2 both in healthy and alloxan-diabetic groups.

Animals↗
PubMed1982

Cytochemical detection of nickel in the myocardium after acute carbon monoxide intoxication.

The dimethylglyoxim cytochemical method was used for detecting endogenous nickel (Ni) in the canine and human myocardium. Electrondense deposits were observed in the myocardial cells and the wall and lumen of capillaries of the dog heart when after CO-intoxication the blood COHb level exceeded 30%. Energy-dispersive microanalysis proved the presence of Ni in the reaction product. Detection of the Ni-reaction product in the myocardium of human cadavers may be of forensic importance, since the reaction is resistant to post mortem autolysis and may help to identify the cause of death.

Animals↗
PubMed1980

Electrophysiological effects of hypoglycaemic sulphonylureas on rabbit heart.

The hypoglycaemic sulphonylurea drugs glibenclamide and carbutamide were compared as to their influence on the electrical activity of isolated rabbit heart preparations. Carbutamide (10(-5)-10(-3) M) was found to depress slightly the nomotopic and junctional automaticity, while in Purkinje fibres it enhanced automaticity and conduction velocity. On the other hand, glibenclamide (10(-6)-10(-3) M) had no significant influence on the nomotopic and junctional automaticity, and markedly depressed automaticity and conduction velocity in the Purkinje fibres. The atrial conduction system was not much influenced by the sulphonylureas tested. Carbutamide depressed the electrical threshold in Purkinje fibres. It follows that the hypoglycaemic sulphonylurea compounds carbutamide and glibenclamide differ considerably with respect to their influences on cardiac electrical activity.

Action Potentials↗
PubMed1980

Compensatory hyperkinesis of the ventricular walls in acute myocardial ischaemia.

After ligation of the anterior descending coronary artery in dogs, conductance of the left circumflex branch and contractility of the ventricular muscular areas supplied by the left descending coronary artery and its circumflex branch were studied over 60 min. After ligation a considerable increase in contractility of the myocardial areas of the posterior wall with intact blood supply was found and a further increase parallel with a considerably enhanced flow in the circumflex branch. At the same time the contractile power of the anterior ventricular myocardium with a poor blood supply greatly decreased. A close correlation was found between the increase in flow in the circumflex branch and the increase in contractility of the intact areas. The tissue catecholamine level showed a marked increase in the myocardial areas with impaired blood supply.

Acute Disease↗
PubMed1979

Effect of hyperglycaemia-induced hyperosmolality on heart function in the dog.

Changes in myocardial water content, left ventricular diastolic stiffness, cardiac performance, coronary blood flow, myocardial contractile force, rate of change of myocardial force, and peak acceleration of the aortic volume flow were examined in twenty-five dogs during glucose-induced hyperosmolality before and after pancreatectomy, the latter with and without insulin treatment. Glucose-induced hyperosmolality accounted for myocardial dehydration, increased diastolic stiffness and consequent decrease of left ventricular performance only in the absence of insulin, while coronary blood flow, myocardial contractile force, rate of change of myocardial force and peak acceleration of the aortic volume flow increased independently from the presence or absence of insulin during the glucose-induced hyperosmolality. These findings suggest that the frequent development of heart failure in hyperosmolar diabetic coma could partly be explained by myocardial dehydration and by the consequent decrease in left ventricular compliance and performance.

Animals↗
PubMed1979

The effect of hyperosmotic mannitol and glucose on heart function.

In the dog heart-lung preparation the effects of glucose and mannitol induced hyperosmolality were examined on left ventricular water content, ventricular compliance, cardiac performance, and coronary blood flow. Glucose-induced increase of serum osmolality by more than 20% resulted in a decrease of myocardial water content and an increase of left ventricular diastolic stiffness if insulin was absent, but the changes did not develop if it was present. Insulin failed to prevent the alterations if hyperosmolality was induced with the nonmetabolizable sugar, mannitol. Coronary blood flow increased in each type of experiments. It is concluded that diagnostic and clinical treatment with hyperosmotic solutions of nonmetabolizable agents can account for disturbed left ventricular compliance and decreased cardiac performance, as it may occur in hyperosmolar diabetic coma.

Animals↗
PubMed1979

Effect of propranolol on drug-induced and physiological glycogenolysis in the liver.

The beta-adrenergic blocking agent propranolol had in itself no notable influence on the blood glucose level in rats, but in combination with chlorpropamide it considerably delayed and enhanced the hypoglycaemic and liver glycogenolysis depressing actions of chlorpropamide. This effect was still more pronounced when the rats were treated in addition to propranolol and chlorpropamide with thyroxine or glanduitrine, which in themselves act as stimulators of liver glycogenolysis. The simultaneous administration of propranolol and chlorpropamide depressed considerably the liver glycogenolysis induced by prolonged fasting and inhibited completely the liver glycogenolysis observed after hepatectomy. The reports available in the literature on propranolol-precipitated hypoglycaemia in patients are surveyed and it is supposed that the beta-adrenergic blocking agent produces hypoglycaemia primarily through the depression of liver glycogenolysis. This observation supports the hypothesis that the adrenergic beta-receptors play an important role in the sympathetic control of liver glycogenolysis.

Animals↗
PubMed1978

The influence of hyperosmolality on heart function.

Hyperosmolality produces a reduction in myocardial water content, an increase in ventricular stiffness and coronary blood flow, and decrease in ventricular performance. The alterations of myocardial dehydration and ventricular stiffness are more pronounced in glucose-induced, and those of ventricular performance in urea-induced hyperosmolality.

Animals↗
PubMed1978

Effect of catecholamines on insulin secretion and liver glycogenolysis in the rat.

The relative activities of adrenaline, noradrenaline and isoprenaline in producing hyperglycaemia, hyperinsulinaemia and glycogenolysis in liver and skeletal muscle have been studied in both fed and fasted rats. Independent of prandial state isoprenaline significantly elevates plasma insulin level. Noradrenaline has no demonstrable glycogenolytic action in the liver even at a dose of 1 mg/kg regardless to the prandial state. These observations suggest that in the intact organism enhanced insulin-secretory effect of isoprenaline counteracts and masks the glycogenolytic effect of this drug in the liver.

Animals↗
PubMed1977

The direct effect of hypoglycaemic sulphonylureas on myocardial contractile force and arterial blood pressure.

The cardiovascular effects of glibenclamide, gliclazide and carbutamide were studied on myocardial contractile force, cardiac output, mean arterial pressure and heart rate in 43 intact, 14 pancreatectomized and 18 adrenalectomized dogs. It is shown that a positive inotropic and hypertensive effect of hypoglycaemic sulphonylureas develops without the mediation of glucagon, insulin or adrenaline. Contrary to the other investigated sulphonylureas, glibenclamide reduced myocardial contractile force and arterial blood pressure.

Adrenalectomy↗
PubMed1976

Effect on carbohydrate metabolism of hypotensive adrenergic neurone blocking agents.

In subjects with normal metabolism sugar tolerance was not appreciable influenced by 4 or 5-day courses of guanethidine and guanazodine. Upon perfusion in isolated rat liver, glycogen metabolism and hepatic sugar release were increased by guanazodine, guanethidine and debrisoquine alike. However, when these drugs were used simultaneously with chlorpropamide debrisoquine proved to be the weakest in counteracting the inhibitory effect of chlorpropamide on glycogen metabolism and sugar release. The observation may have clinical significance.

Adolescent↗