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Biomedical subjects

G Pogátsa

Publications and source records attributed to G Pogátsa.

At least 37 records · Page 2Linked to original sources
PubMed1990

[Correlations between cardiorespiratory reflex impairment and distal neuropathy in diabetics free of clinical symptoms of autonomic neuropathy].

Signs of autonomic cardiac neuropathy and its association with distal symmetrical polyneuropathy were investigated in adult diabetic patients free from clinical symptoms of autonomic neuropathy. Cardiorespiratory reflexes were assessed by non-invasive tests (deep-breathing, Valsalva manoeuvre and lying-to-standing) evaluating parasympathetic function of cardiac innervation. Measurement of motor nerve conduction velocity in both peroneal nerves and neurological physical examination were carried out for assessment of distal somatic neuropathy. Among 64 diabetics, definitive signs of cardiac autonomic neuropathy were found in 28 patients (44%), early signs of cardiac autonomic neuropathy were observed in 19 patients (30%) while no alterations were documented in 17 patients (26%). The values of motor nerve conduction velocity in peroneal nerves (41.8 +/- 0.7 m/s) were significantly (p less than 0.01) lower in patients with definitive cardiac autonomic neuropathy (n = 28) than those (45.8 +/- 1.1 m/s) of patients without any signs of cardiac autonomic neuropathy (n = 17). These latter values were, however, significantly (p less than 0.001) lower than those (53.7 +/- 0.7 m/s) of control subjects (n = 50). Abnormal results of non-invasive tests for autonomic neuropathy, i.e. alterations of cardiorespiratory reflexes indicating parasympathetic impairment in cardiac innervation could be often found in diabetics without clinical signs of autonomic neuropathy. These alterations could be frequently observed in diabetics with distal symmetrical neuropathy as well as in diabetic patients with one or more late specific complications.

Autonomic Nervous System Diseases↗
PubMed1990

Divergent cardiac effects of the first and second generation hypoglycemic sulfonylurea compounds.

The effects of first and second generation hypoglycemic sulfonylureas on the incidence of ventricular ectopic beats and on the duration of transitional ventricular fibrillation in the ischemic rat heart were investigated. First generation sulfonylurea compounds (tolbutamide, carbutamide and gliclazide) in 105 preparations increased, while second generation sulfonylurea compounds (glibenclamide and glipizide) in 50 preparations decreased in a dose-dependent manner both the number of ventricular ectopic beats and the duration of transitional ventricular fibrillation during the first 30 min after ligation of the left anterior descending coronary artery. Therefore, second generation sulfonylureas should be preferred in the treatment of type 2 diabetics with ischemic heart diseases, if satisfactory metabolic control cannot be achieved by a treatment regimen and diet alone.

Animals↗
PubMed1990

Impairment of cardiorespiratory reflexes and its association with distal somatic neuropathy in diabetic patients free from clinical symptoms of autonomic neuropathy.

Signs of autonomic cardiac neuropathy and its association with distal somatic neuropathy were investigated in 36 type 1 and 28 type 2 diabetic patients free from clinical symptoms of autonomic neuropathy. Using bedside tests (deep-breathing, Valsalva manoeuvre and lying-to-standing) definitive cardiac autonomic neuropathy was found in 28 patients (44%), early cardiac autonomic neuropathy was observed in 19 patients (30%) while 17 patients (26%) showed no alterations. The values of motor nerve conduction velocity in peroneal nerves (41.8 +/- 0.7 m/s, mean +/- SEM) were significantly (p less than 0.01) lower in patients with definitive cardiac autonomic neuropathy than those (45.8 +/- 1.1 m/s) of patients without any signs of cardiac autonomic neuropathy. These latter values were, however, significantly (p less than 0.001) lower than those (53.7 +/- 0.7 m/s) of control subjects (n = 50). Signs of early or definitive cardiac autonomic neuropathy were recorded in 31 of 35 diabetic patients with distal somatic neuropathy assessed by measurement of motor nerve conduction velocity in peroneal nerves. It was concluded that abnormal results of noninvasive tests for autonomic neuropathy, i.e. alterations in cardiorespiratory reflexes indicating parasympathetic impairment of cardiac innervation could be often found in diabetic patients without clinical signs of autonomic neuropathy. These alterations could be frequently observed in diabetic patients with distal symmetrical somatic neuropathy.

Adult↗
PubMed1990

Increased vasoconstrictor response to noradrenaline in femoral vascular bed of diabetic dogs. Is thromboxane A2 involved?

STUDY OBJECTIVE: The aim was to determine the role of cyclo-oxygenase products in the vasoconstrictor response of femoral arterial bed to noradrenaline and to analyse the role of vascular adrenoceptors in the synthesis of cyclo-oxygenase products. DESIGN: The influence of intra-arterially injected cyclo-oxygenase inhibitors indomethacin and acetylsalicylic acid on alterations in conductance of femoral arterial bed induced by noradrenaline was compared in metabolically healthy and alloxan diabetic dogs. PGI2 and TXA2 synthesising ability of isolated femoral arterial rings was measured with and without inhibition of alpha adrenoceptors by phentolamine. SUBJECTS: 18 metabolically healthy and 18 alloxan (560 mumol.kg-1) diabetic dogs of either sex, weight 16-28 kg, were studied. MEASUREMENTS AND MAIN RESULTS: Noradrenaline produced greater (p less than 0.01) pressor effects in the femoral arterial bed of alloxan diabetic dogs than in the hind limb of control animals. Blockade of cyclo-oxygenase either by indomethacin 10 mumol.kg-1 or by acetylsalicylic acid 140 mumol.kg-1 markedly reduced the response to noradrenaline in alloxan treated animals, but not in controls, thereby eliminating the different responsiveness of the two groups. Femoral arterial rings from diabetic animals synthesised similar amounts of PGI2 as control rings but formed more TXA2 (p less than 0.05). Phentolamine pretreatment (5 mumol.litre-1) markedly reduced the production of TXA2, but not of PGI2, in diabetic vessels. CONCLUSIONS: The results show an increased release of TXA2 by isolated diabetic femoral arteries. It is therefore suggested that an alpha adrenoceptor mediated increase in TXA2 biosynthesis may play a part in the vascular hyperreactivity of the diabetic femoral arterial bed.

Animals↗
PubMed1990

Left ventricular diastolic dysfunction in type 1 (insulin-dependent) diabetic patients during dynamic exercise.

The left ventricular diastolic and systolic functions were assessed in 27 strictly selected type 1 diabetic patients without overt heart disease and 50 age- and sex-matched control subjects. For evaluating left ventricular performance, complex mechanocardiography including digitized apexcardiography was used at rest and after symptom-limited, graded dynamic exercise. The values of diastolic/systolic time intervals and amplitude parameters did not differ significantly between the diabetic and control groups at rest. A longer value of corrected early apexcardiographic relaxation time (diabetics: 38.7 +/- 2.6 ms, controls: 17.3 +/- 2.1 ms, p less than 0.001) and a smaller normalized amplitude of relaxation (diabetics: 0.014 +/- 0.004 ms-1, controls: 0.056 +/- 0.006 ms-1, p less than 0.001) were observed after dynamic exercise suggesting disturbances of the early diastole in diabetic patients. No correlations could be found between the diastolic abnormalities and the diabetic control. Significant correlation was observed between the diastolic disorders and the duration of diabetes mellitus. Testing left ventricular performance by complex mechanocardiography including digitized apexcardiography after dynamic exercise in patients with type 1 diabetes might be useful for recognizing diastolic abnormalities even when no alterations could be identified at rest. Diastolic disorders could appear in diabetic patients without overt heart disease and clinical symptoms. Left ventricular systolic function might be normal, although exercise-induced alterations of diastolic function might already be present in type 1 diabetic patients.

Adolescent↗
PubMed1989

[Changes in the heart in diabetes].

The structure of the heart muscle, its metabolism and functional changes which develop in diabetes are the basic concepts elucidated by the author from the aspect of present knowledge. Attention is drawn to possible prevention of their development.

Diabetes Complications↗
PubMed1989

Altered responsiveness of diabetic dog renal arteries to acetylcholine and phenylephrine: role of endothelium.

The mechanical responses to acetylcholine (ACh), sodium nitroprusside and phenylephrine (PE) were determined in normal and diabetic dog renal arterial strips with and without endothelium. Experimental diabetes increased the sensitivity, IC50 = (2.9 +/- 0.4) X 10(-8) mol/l in normal and (9.6 +/- 1.5) X 10(-9) mol/l in diabetic (p less than 0.01, n = 6) to ACh of endothelium intact renal arterial strips without influencing the maximum relaxation induced by this agonist. In all intact vessels PE produced contractions of equal magnitude. Removal of the endothelium completely abolished the relaxant ability of ACh, and caused a slight increase in the contractile response of both diabetic and normal strips to PE. The maximum contractile force generated by the denuded diabetic vessels in response to PE was significantly (p less than 0.01) greater than the maximum tension produced by the denuded nondiabetic arteries. The sensitivity of the tissues to PE was, however, not modified by either diabetes or endothelium removal. The direct relaxant sodium nitroprusside elicited a similar degree of relaxation in the two groups of arteries. Cyclooxygenase blockade had no effect on either the relaxation or contractile responses of any of the preparations. These findings suggest that short-term diabetes makes dog renal arteries supersensitive to ACh and hyperreactive to PE.

Acetylcholine↗
PubMed1989

Effects of first and second generation sulphonylureas on cardiotoxicity of strophanthidin in rabbits.

The effects of the first generation sulphonylurea compound gliclazide and the second generation sulphonylurea compound glipizide on strophanthidin toxicity was investigated in rabbits. The sulphonylurea pretreated animals were intravenously infused with 23 mumol/kg strophanthidin until the appearance of the first ventricular ectopic beat and continued thereafter until the appearance of ventricular fibrillation. The first generation sulphonylurea gliclazide increased, while the second generation sulphonylurea glipizide decreased the strophanthidin toxicity in a dose dependent manner. It was concluded that instead of first generation sulphonylureas, second generation sulphonylureas must be preferred in cardiac glycoside treated diabetics, when sulphonylurea treatment is necessary.

Animals↗
PubMed1988

Relationship between vascular adrenergic receptors and prostaglandin biosyntheses in canine diabetic coronary arteries.

Before the onset of histologically detectable alterations of diabetic arteries, a considerable decrease of vasodilation ability develops. The role of an altered prostaglandin biosynthesis in this phenomenon was investigated in connection to the altered vascular adrenergic mechanisms. The effect of phenylephrine on prostacyclin production of isolated coronary arterial rings (100 mumol/l) as well as on conductivity of the coronary arterial bed (7.5-15-30-60 pmol. kg-1.min-1) were compared in 12 metabolically healthy and 12 alloxan-diabetic (560 mumol/kg) dogs. Furthermore, the effect of phentolamine (5 mumol/l) on the prostacyclin and thromboxane productions of the isolated vessels (coronary, femoral and basilar arteries) was investigated by radioimmunoassay. Although the basal prostacyclin amounts synthesized by healthy and diabetic coronary vessels were not different (5.1 +/- 1.6 and 4.9 +/- 1.4 pg/mg vessel/30 min), similarly to femoral and basilar arteries, the diabetic arterial rings produced significantly (p less than 0.05) more thromboxane than the control rings. The alpha-adrenergic blockade by phentolamine did not influence the prostacyclin production in the healthy arteries, but considerably (p less than 0.05) increased it in the diabetic coronary arteries. Phentolamine normalised the thromboxane synthesis in the diabetic group (p less than 0.01) and enhanced (p less than 0.05) it in the metabolically healthy group. Phenylephrine was ineffective (98 +/- 6%) on the prostacyclin production in vitro versus the stimulated (150 +/- 22%) prostacyclin synthesis detected in the metabolically healthy group; and in vivo induced a more significant (p less than 0.05) decrease in the coronary conductivity in diabetic than in control groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Influence of experimental diabetes on the mechanical responses of canine coronary arteries: role of endothelium.

The influence of experimental diabetes on the endothelium mediated relaxation and contractile responses of canine isolated coronary arteries was studied in arteries removed from alloxan treated diabetic (280 mmol.kg-1) and control mongrel dogs. Strips with and without endothelium were suspended in Krebs bicarbonate solution for isometric recording. Relaxation responses to acetylcholine (1.8 X 10(-8) to 9.4 X 10(-6) mol.litre-1, A23187 (10(-8) to 1.28 X 10(-6) mol.litre-1), and sodium nitroprusside (10(-9) to 10(-7) mol.litre-1) as well as contractile responses to prostaglandin F2 alpha, (1.7 X 10(-7) to 5.6 X 10(-4) mol.litre-1) were determined. In all intact strips acetylcholine, and A23187 induced similar concentration dependent reduction of the prostaglandin F2 alpha (2 X 10(-6) mol.litre-1) evoked tone. No significant difference was observed between sodium nitroprusside evoked relaxations of normal and diabetic arteries. Cyclooxygenase blockade reduced the maximal relaxations induced by acetylcholine and A23187 in diabetic vessels, whereas it did not change the endothelium dependent relaxation of normal arteries. Diabetes increased significantly the sensitivity to acetylcholine (EC50 4.1(0.4) X 10(-7) mol.litre-1 in control and 6(0.7) X 10(-8) mol.litre-1 in diabetic arteries; p less than 0.01, n = 7) and to A23187 (EC50: 7(1) X 10(-8) mol.litre-1 in control and 3.8(0.3) X 10(-8) mol.litre-1 in diabetic vessels; p less than 0.01, n = 7); in contrast, prostaglandin F2 alpha remained an equiactive constrictor in normal and diabetic vessels with intact endothelium.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗
PubMed1988

Insulin induced reversibility of altered responsiveness in femoral arterial bed of diabetic dogs.

The altered reactivities of femoral arterial bed to noradrenaline, phenylephrine, adenosine and prostacyclin were compared in 18, clinically manifest but aketotic, alloxan diabetic mongrel dogs. Alloxan treatment markedly increased the vasoconstrictor responses to noradrenaline and phenylephrine, as well as the adenosine-induced vasodilation in the femoral vasculature. These changes were prevented or normalized, respectively, in the early or late insulin-treated alloxan diabetic animals. In the case of noradrenaline not only a normalization but also an explicit overcompensation could be observed by insulin treatment. The altered reactivity to prostacyclin could not be influenced by insulin therapy. These results indicate a significant difference in the effect of insulin treatment on the altered diabetic vascular responsiveness to catecholamines and adenosine or to prostacyclin.

Animals↗
PubMed1988

Influence of diabetic state on coronary vasoregulation in myocardial hypoxia.

It is a matter of common knowledge that under ischaemic or hypoxic conditions the oxygen demand of the myocardium could only be satisfied by enhancement of collateral blood flow. It is demonstrated that in a diabetic state an elevation of the myocardial blood flow could not develop due to lack of proper vasodilation in the coronary arterial bed.

Animals↗
PubMed1988

Contractile and relaxant responses of diabetic dog femoral arteries.

Strips of femoral arteries of normal and alloxan-treated dogs were set up for isometric recording. The contractile response to phenylephrine and the relaxant response to acetylcholine were determined. Neither alloxan treatment nor mechanical removal of endothelium altered the EC50 value for phenylephrine. The slope of phenylephrine dose-response curves of diabetic and healthy vessels with intact endothelium was similar, whereas the slope of phenylephrine dose-response curves of endothelium-denuded diabetic arteries was significantly greater than that of the denuded healthy arteries. Removal of the endothelium completely abolished the relaxant effect of acetylcholine. The relaxant potency (IC50) of acetylcholine was not affected by alloxan treatment. The results suggest that in canine femoral arteries the relaxant activity of acetylcholine is unaffected in experimental diabetes and the damage of the arterial endothelium may play a role in the increased responsiveness of diabetic vessels to adrenergic agonists.

Acetylcholine↗
PubMed1988

Ultrastructural alterations in cardiac and skeletal muscles in experimental diabetes mellitus.

In 18 alloxan-diabetic and 12 metabolically healthy dogs cardiac and skeletal muscles have been studied electronmicroscopically. Myopathy-like alterations, as widening of Z band material, alterations of mitochondria as well as of collagen fibers were observed in the diabetic myocardium. In skeletal muscle nemalin bodies were found. These latter alterations don't develop in insulin-treated diabetic state.

Animals↗
PubMed1988

Left ventricular diastolic function in diabetics.

Left ventricular diastolic function was studied in 29 young diabetic patients (aged from 14 to 44 years) without any clinical sign of heart disease. The metabolic state, the presence and the degree of microvascular and neuropathic complications have been established. Age and sex matched 32 healthy subjects served as controls. The parameters of left ventricular diastolic function were determined by means of phonomechanocardiography. By this method in diabetic patients impaired diastolic function of the left ventricle was found. This alteration could be best characterized by the values of normalized relaxation index referring to the isovolumetric relaxation of the left ventricle. A close correlation was found between the microvascular and neuropathic complications and the left ventricular diastolic dysfunction, while no correlation could be demonstrated between the metabolic state and the diastolic cardiac disorder.

Adult↗