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Biomedical subjects

G Pogátsa

Publications and source records attributed to G Pogátsa.

At least 55 records · Page 3Linked to original sources
PubMed1988

The effect of various hypoglycaemic sulphonylureas on the cardiotoxicity of glycosides and arrhythmogenic activity due to myocardial ischaemia.

The effects of different sulphonylureas on the electrical cardiac activity were studied in 145 rabbits and in 103 rats as well as in 278 digitalis-treated, non-smoker non-insulin-dependent diabetics on the same therapy at least during the previous three months. In rabbits and rats glibenclamide (0.0032-100 mumol. kg-1) decreased, while tolbutamide and carbutamide (0.008-1000 mumol. kg-1) increased strophantidin toxicity and myocardial ischaemia induced transitory ventricular fibrillation dose-dependently. The differences between the dose-response curve of glibenclamide and those of tolbutamide or carbutamide were significant. In digitalized non-insulin-dependent diabetics, multifocal ectopic ventricular beats could be observed in none among the 80 glibenclamide-treated diabetics, while in 12 cases of the 71 tolbutamide and in 10 cases of the 61 carbutamide treated diabetics. Two of the 66 non-insulin-dependent diabetics receiving only diet and 7 of the 278 age and sex matched, non-smoker, metabolically healthy patients had multifocal ectopic ventricular beats. No significant difference could be found between the therapeutical groups. It was concluded that instead of tolbutamide, glibenclamide must be preferred in digitalis-treated diabetics, when metabolic control is not satisfactorily achieved by diet and regime alone.

Animals↗
PubMed1987

Differential contractile responsiveness of femoral arteries from healthy and diabetic dogs: role of endothelium.

Phenylephrine-induced contraction and acetylcholine-induced relaxation of isolated femoral arterial strips (with and without endothelium) of diabetic (alloxan-treated) and metabolically healthy dogs were determined. Alloxan treatment did not change the contractile responsiveness to phenylephrine (PE) of the arteries with intact endothelium. After mechanical removal of the endothelial layer, however, the maximum force generated by the diabetic vessels (22.0 +/- 2.0 mN.m-2) significantly exceeded the maximum contraction produced by the nondiabetic arteries (14.6 +/- 1.8 mN.m-2). The dose-response curve of diabetic arteries to PE was steeper than it was in non-diabetic strips. The EC50 values for PE were similar in these two groups (0.45 +/- 0.12 and 0.58 +/- 0.20 mumol/l in diabetic and nondiabetic vessels, respectively). In the arteries with intact endothelium, acetylcholine produced concentration-related reduction of PE-induced tone. This endothelium-dependent relaxant activity of acetylcholine was similar in the healthy and diabetic arterial strips, IC50 for acetylcholine being 0.17 +/- 0.02 and 0.20 +/- 0.03 mumol/l, respectively. These results suggest that functional alteration of endothelium (probably an increased release of EDRF) prevails in diabetes. This may be important in reducing the hyper-responsiveness of diabetic arterial smooth muscle to PE.

Animals↗
PubMed1986

Circulating blood volumes in diabetic patients.

To examine the mechanism of cardiac dysfunction in diabetes, total circulating blood volume, cardiac and stroke volumes were measured by radioisotope method in 44 patients with type 1 and type 2 diabetes. Considerable difference in actually circulating blood volume could be demonstrated in diabetic patients, which seemed to be dependent on the control of the carbohydrate metabolism. The achievement of well controlled carbohydrate metabolism in diabetics has a great importance with special respect also to the blood volumes.

Adult↗
PubMed1986

Direct cardiac effects of an ionic and a non-ionic contrast medium in dogs.

Direct cardiac effects of ionic diatrizoate (Uromiro) and non-ionic iopamidol (Iopamiro) were investigated in "in situ" heart-lung preparation of 19 vagotomized dogs. Diatrizoate was found to induce considerably greater alteration in plasma osmolality and subsequent dehydration of the myocardium compared with iopamidol. Myocardial dehydration resulted in a decrease of left ventricular compliance and in that of cardiac performance. Diatrizoate was shown to influence the myocardium not only by its hyperosmolarity but also by a direct action. Heart rate was reduced by both contrast media.

Animals↗
PubMed1985

Effects of various hypoglycaemic sulphonylureas on the cardiotoxicity of glycosides.

In diabetic patients it has been shown that tolbutamide and carbutamide enhanced and glibenclamide did not influence the incidence of digitalis intoxication, or that of multifocal ectopic beats or coupling due to premature ectopic ventricular beats during digitalis therapy. In rabbits glibenclamide decreased and tolbutamide and carbutamide increased strophanthidin toxicity in a dose dependent manner. It was concluded that glibenclamide should be preferred to tolbutamide or carbutamide in digitalis-treated diabetics, when satisfactorily metabolic control is not achieved with a dietary regime alone.

Aged↗
PubMed1984

Diabetic myocardial alterations in ultrastructure and function.

Myocardial samples taken from six healthy and six alloxan-diabetic dogs by means of percutaneous needle-biopsy were investigated electronmicroscopically. Specific increase in the number of collagen fibers and that of mitochondria were demonstrated beside the widening of Z bands. In the same experimental animals, a close, inverse correlation was detected (y = 0.0068x + 0.1680; r = 0.8648; F = 29.6705; n = 12) between the values of the left ventricular passive elastic modulus and those of the plasma glucose disappearance rate determined immediately before the haemodynamic investigation. On the basis of the ultrastructural findings, the proliferation of collagen fibers can be made also responsible for functional disorder of the diabetic myocardium.

Animals↗
PubMed1984

Effects of cyclooxygenase inhibitors, prostaglandins F2 alpha and I2, on isolated coeliac and basilar arteries of alloxan-diabetic dogs.

The effects of prostaglandin synthetase inhibitors PGF2 alpha and PGI2 on the tone of isolated basilar and coeliac arteries were studied in healthy and alloxan-diabetic dogs. PGF2 alpha (1 mumol 1-1) produced a significantly higher tone in diabetic basilar arteries (1.15 +/- 0.16 mN) than in normal cerebral vessels (0.7 +/- 0.10 mN). By contrast, the contractile responses of normal and diabetic coeliac arteries to PGF2 alpha did not differ. The cyclooxygenase inhibitors indomethacin (3 mumol 1-1) and suprofen (0.58 mumol 1-1) potentiated the PGF2 alpha-evoked contractions in all of the vessels studied. The percent potentiation was greater (50-60%) in the basilar arteries from alloxan-treated dogs than in normal basilar vessels (22-30%). There was not such a difference between diabetic and normal coeliac arteries. Prostacyclin produced a concentration-related relaxation in the presence of indomethacin or indomethacin + PGF2 alpha. The relaxant potencies of PGI2 were similar in the vessels from metabolically healthy and diabetic dogs. The IC50 values for PGI2 were 11.6 +/- 1.3 and 11.8 +/- 1.8 nmol 1-1 in normal and diabetic basilar arteries, respectively; they were 25.4 +/- 3.2 and 26.2 +/- 3.9 nmol 1-1 in control and alloxan-treated coeliac vessels. These results indicate that normal and diabetic vessels may have differential reactivity to cyclooxygenase inhibitors, this difference being dependent on the vascular region.

Animals↗
PubMed1984

Myocardial systolic alterations of insulin-dependent diabetics in rest.

Left ventricular systolic function was tested in 27 insulin-dependent diabetic patients by measuring the systolic time intervals. In diabetics longer pre-ejection period, and higher PEP/LVET quotient were found showing a good correlation with the values of glycosylated haemoglobin. These findings emphasize the importance of metabolic control in the development of cardiac dysfunction.

Adolescent↗
PubMed1984

The effects of sympathetic stimulation and adenosine on coronary circulation and heart function in diabetes mellitus.

The aim of the experiment was to clarify whether the altered coronary reactivity in diabetes mellitus might be caused by a general modification of the sympathetic responses. Six of 12 young mongrel dogs of both sexes were made diabetic with alloxan (560 mmol/kg). This amount of alloxan induced a clinically manifest diabetes, however the animals failed to develop ketosis. The remaining six dogs served as controls. The haemodynamic investigation was performed three months after the induction of diabetes. Under pentobarbital anaesthesia (133 mmol/kg) mean arterial blood pressure, blood flow in the left anterior descending coronary artery, myocardial contractile force of left ventricular wall and heart rate were recorded continuously and the conductivity of coronary arterial bed was calculated during electrical stimulation ( 8V , 1-2-4-8-20 s-1) of the cardiac plexus or during the intracoronary infusion of adenosine (30-60-120-240-480 nmol/kg/min). In alloxan-diabetic dogs electrical stimulation evoked vasoconstriction in the coronary arterial bed, while vasodilation was observed in metabolically healthy animals. The vasodilator effect of adenosine was significantly smaller in diabetic than in control dogs. On the other hand there were no differences either in the alterations of heart rate caused by adenosine or in those of myocardial contractile force induced by adenosine or electric stimulation between the two groups. It is concluded that general alteration of sympathetic responses is not, but rather a modified relation of the receptors to the vessel wall might be responsible for the altered vascular responses in diabetes.

Adenosine↗
PubMed1983

Altered hyperemic response of the coronary arterial bed in alloxan-diabetes.

Reactive hyperemic responses of the coronary arterial bed, provoked by asphyxia or clamping of the coronary artery, were compared in alloxan-diabetic and metabolically healthy dogs. In alloxan-diabetic dogs the response of the coronary arterial bed lasted longer, and its reactivity to hypoxia was lower. Treatment with adenosine caused less vasodilation in diabetic animals than in controls. These changes may be due to the altered reactivity of diabetic vascular smooth muscle.

Adenosine↗
PubMed1983

Electron-cytochemical detection of endogenous nickel in the myocardium in acute carbon monoxide poisoning. Applicability of a new cytochemical technique in forensic medicine.

After acute carbon monoxide poisoning (inhalation, dogs; perfusion, rats; postmortem, humans) endogenous nickel was cytochemically detected in heart muscle by dimethylglioxime reaction. Dimethylglioxime cytochemical reaction, in each case at the COHb level, was always positive in experiments and in postmortem samples. A nickel ion accumulation in the heart muscle above 30 rel.% of COHb was suggested. A possible role of nickel ion in the pathomechanism of the acute carbon monoxide poisoning was supposed. This dimethylglioxime cytochemical technique is applicable in forensic medical practice, primarily because it is not disturbed by autolysis.

Animals↗
PubMed1982

[Studies of glycosylated hemoglobins and albumins in diabetes mellitus with retinopathy].

The correlation between the diabetic retinopathy and the levels of glycosylated haemoglobin and albumin was examined in 133 diabetic patients. 25 healthy persons served as controls. 53 out of the 133 diabetic patients suffered in different grades of diabetic retinopathy, 80 diabetics developed no retinopathy. There was no significant difference in the age of patients with or without retinopathy. The duration of diabetes was significantly longer in diabetics with retinopathy. The glycosylated haemoglobin and albumin levels of diabetics were significantly higher as compared to the levels of the controls. There was no difference in the glycosylated haemoglobin and albumin levels of diabetic patients with or without retinopathy. According to these results there is no correlation between the formation of diabetic retinopathy and the elevated levels of glycosylated haemoglobin and albumin. Thus the development of diabetic retinopathy takes many years, the cause of our results may be the relative short period of the examinations. Following this study we do hope to get more data to this important question.

Adult↗