PubMed Health⌕ Search

Biomedical subjects

A Végh

Publications and source records attributed to A Végh.

At least 19 recordsLinked to original sources
PubMed1998

The dopamine receptor agonist Z1046 reduces ischaemia severity in a canine model of coronary artery occlusion.

Z1046, (S)-6[[6-[[2-(2-methoxyphenoxy)ethyl]amino]propyl]amino]-5,6,7,8-tetra-h ydro-1,2-naphtalenediol dihydrochloride, is an agonist at both dopamine D1 and D2 receptors. Since stimulation of dopamine D2 receptors inhibits noradrenaline release, and because cardiac noradrenaline release has been implicated in the genesis of early ischaemia-induced, life-threatening ventricular arrhythmias, the effect of Z1046 has been examined for its effects on coronary artery occlusion in chloralose urethane anaesthetised mongrel dogs. Z1046 (10 microg kg(-1) intravenously or 1 microg kg(-1) by local intracoronary injection) decreased heart rate and reduced arterial blood pressure and coronary blood flow, effects prevented by the prior administration of domperidone (40 microg kg(-1) i.v.). The ischaemic changes induced by a 25-min occlusion of the left anterior descending coronary artery (including ST-segment elevation and ventricular ectopic activity) were much less marked in those dogs administered Z1046 and survival from the combined ischaemia reperfusion insult was increased from 7% to 36% (P < 0.05). These effects of Z1046 were partly attenuated by domperidone. We conclude that the anti-ischaemic effects of Z1046 are due to inhibition of cardiac sympathetic responses. Studies using rat isolated perfused mesenteric vascular bed preparations subjected to sympathetic nerve stimulation confirmed that Z1046 inhibits synaptic transmission without modifying vascular responses to noradrenaline.

Animals↗
PubMed1997

Modification by bradykinin B2 receptor blockade of protection by pacing against ischaemia-induced arrhythmias.

In dogs, rapid cardiac pacing, by way of a pacing electrode in the right ventricle, protects against ventricular arrhythmias when a coronary artery is occluded immediately after cessation of the pacing period. This represents a form of ischaemic preconditioning. The role of bradykinin in mediating the protective effects of rapid cardiac pacing in this model was investigated using a selective antagonist of bradykinin at B2 receptors (icatibant; HOE 140). In the presence of icatibant cardiac pacing (220 beats min(-1)) resulted in more severe ischaemia (as assessed by ST-segment elevation from the pacing electrode at the end of the stimulus) and to a higher incidence of ventricular arrhythmias during the pacing protocol. When the coronary artery was occluded under such conditions the antiarrhythmic protection afforded by cardiac pacing was not seen although other indices of reduced ischaemia severity (epicardial ST-segment mapping; changes in the degree of inhomogeneity of electrical activation within the ischaemic area) were not affected by icatibant treatment. These results suggest that bradykinin is an important trigger mediator involved in the protective effects of cardiac pacing. Whether this is due to the generation of endothelium-derived protective substances (such as nitric oxide and prostacyclin) or whether it results from a direct effect on B2 receptors in cardiac myocytes is unclear.

Adrenergic beta-Antagonists↗
PubMed1997

Two methods in the treatment of prostate cancer T1-T2.

The author reports experience of 82 radical retropubic prostatectomies. In accordance with the length of isolable urethra two methods were applied. In one of the methods the bladder-neck was pulled down to the floor of the pelvis by a synthetic reabsorbable thread (40 cases), in the other method, the urethra-trunk was sewn up to the bladder-neck (42 cases). The early and later complications are dealt with. Their findings: the blood transfusion during intra and perioperative period was identical in both methods. Injury of ureter did not occur, injury of rectum in one case (1.2%) occurred. In the two methods incidence of impotence (85%) and incontinence (15%) were identical. The length of operation was on an average twenty minutes shorter in the pull-down technique but stricture occurred in 4.7%. In the sewing method no stricture occurred. In the opinion of the author the pull-down technique at the short (5-7 mm) urethra-trunk, while the direct sewing-up technique at the long (7-20 mm) urethra-trunk were applied.

Absorption↗
PubMed1996

Haemodynamic and other effects of sulphonylurea drugs on the heart.

Antidiabetic sulphonylureas have attracted a great deal of interest in experimental cardiology to evaluate the role of ATP-sensitive potassium channels in the cardiovascular system. It is well established that KATP channels are present in cardiac cells and also in vascular smooth muscle cells and are implicated in the regulation of myocardial and vascular function. It follows that drugs which open, or inhibit the opening of these channels, might profoundly modify cardiovascular function both under physiological and pathophysiological conditions. This paper reviews the evidence for the role of KATP channels in the cardiovascular system and discusses how the different generations of sulphonylurea drugs interfere with cardiac function. We will particularly concentrate on the haemodynamic effects of different sulphonylureas and shortly discuss how these drugs modify ischaemia-reperfusion arrhythmias.

Adenosine Triphosphate↗
PubMed1996

Cardiovascular effects of conventional sulfonylureas and glimepiride.

Sulfonylureas have, in the past, been reported to have adverse cardiovascular effects. Glimepiride is a new sulfonylurea. In spite of stimulating less insulin secretion, it has, depending on the species, equal or higher blood glucose decreasing activity and according to preliminary studies less cardiovascular activity than glibenclamide. Further studies were performed to confirm the lower cardiovascular activity of glimepiride. The IC50 for inhibition of rilmakalim-activated KATP channel currents in isolated ventricular myocytes was 31.6 nM for glimepiride and 6.8 nM for glibenclamide. In endotoxin shock-rats at a dose of 1 x 2 mg/kg i.v., glibenclamide induced a significantly higher blood pressure increase than glimepiride. At two i.v. doses of 20 mg/kg 4 min apart, in normal rats, glibenclamide produced signs of ischemia in the ECG in nearly all animals, glimepiride almost none, in diabetic rats, glibenclamide produced in all animals a lethal cardiogenic shock preceeded by serious ECG changes, glimepiride only in one fifth of the animals. In open-chest dogs, on intracoronary infusion of equieffective blood glucose-lowering doses, glibenclamide, gliclazide and glimepiride all reduced coronary blood flow, increased coronary resistance, depressed the mechanical activity of the heart, enhanced myocardial O2-extraction, reduced the serum potassium level and induced a moderate endocardial ST-segment elevation, but glimepiride to a significantly less extent than glibenclamide and gliclazide. The presented data confirm that glimepiride at equivalent blood glucose decreasing doses has less cardiovascular activity than conventional sulfonylureas.

Animals↗
PubMed1995

[Transrectal ultrasonography in the diagnosis of prostatic cancer].

There is a summary of experience with 771 transrectal ultrasound examinations. According to the authors, this picture forming method is one of the best diagnostical methods in the malignant tumors of the prostate. In every case, when the digital rectal examination is positive and the serum prostate specific antigen level is above 4 ng/ml, the transrectal ultrasonography should be done as well as the ultrasound guided biopsy of prostate. Besides of these facts, the transrectal ultrasound is useful in the following process of the drug- and/or the radiotherapy for the measurement of the therapeutical effect and the perceptions of recidives.

Aged↗
PubMed1995

Cardiovascular effects of the calcium sensitizer, levosimendan, in heart failure induced by rapid pacing in the presence of aortic constriction.

1. The haemodynamic effects of a novel cardiotonic drug, levosimendan, which has both calcium-sensitizing and phosphodiesterase III (PDE III) inhibitory properties, were studied in conscious dogs in which heart failure had been induced by prolonged cardiac pacing in the presence of aortic constriction. These effects were compared with those in sham-operated dogs with essentially normal cardiac function. 2. Eighteen mongrel dogs were instrumented for the measurement of left ventricular pressure (LVSP, LVEDP) and contractile function (dP/dt; dP/dt/P). In twelve dogs a balloon catheter, positioned in the thoracic aorta, was inflated producing an approximate 60% reduction in effective aortic diameter. Twenty min later rapid ventricular pacing (240 beats mean-1) was commenced and maintained for 48 h by means of a bipolar pacing electrode introduced into the right ventricle. This electrode served also for recording changes in the endocardial electrogram in the absence of pacing. Six of these dogs were used to evaluate the haemodynamic changes of pacing-induced heart failure; a further six of these dogs the haemodynamic changes elicited by levosimendan under these conditions. Six sham-operated dogs (group 2) served as controls. 3. In six dogs (group 1) the haemodynamic alterations were assessed after the development of heart failure. In the presence of aortic constriction, 48 h continuous rapid cardiac pacing resulted in a marked deterioration in left ventricular function which remained stable for at least 48 h after cessation of pacing. Thus, there was a marked reduction in LVSP (15%), +dP/dtmax (35%), -dP/dtmax (36%) and also in dP/dt/P (29%), whereas LVEDP was increased considerably (from 6.4 +/- 1.4 to 20.0 +/- 2.2 mmHg). A marked elevation occurred in endocardial ST-segment (138%), lasting for 20 min.4. Levosimendan was administered intravenously in doses of 0.005, 0.01 and 0.03 micromol kg-1 to 2 groups of conscious dogs. In the sham-operated dogs (group 2), only the higher dose (0.03 micromol kg-1)produced significant increases in LVSP (19%), + dP/dtmax (37%), and in dP/dt/P (32%). In dogs with heart failure (group 3) doses of 0.005, 0.01 and 0.03 micromol kg-1 levosimendan resulted in an improve mentin +dP/dtmax (26%, 38% and 49%), -dP/dtmax (20%, 25% and 38%) and in dP/dt/P (19%, 34%and 50%) and reduction in the elevated LVEDP (from 20 =/- 2.2 mmHg to 16 +/- 1.0, 10 +/- 1.3 and 9 +/- 1.0 mmHg, respectively).5. Levosimendan proved to be a potent cardiotonic drug at the doses used, and was approximately three times more effective under conditions of impaired left ventricular function than in normal hearts.

Analysis of Variance↗
PubMed1995

[Burstone's segmented arch technic].

The authors have introduced the segmented arch technique of Burstone on the base of the literature and of own experiences. They are reporting about the theory and the advantages of the technique and its adaptability in the daily orthodontic practice.

Adult↗
PubMed1991

Cardioprotection: endogenous protective mechanisms promoted by prostacyclin.

Evidence is accumulating that acute stress situations such as ischemia, adrenergic dominance, and ouabain intoxication enhance production of endogenous substances (PgI2, adenosine, NO) which may protect the myocardium from harmful consequences of these stress situations. PgI2 and its stable analogue 7-oxo-PgI2 exert an early direct- and induce a delayed indirect antiischemic, antiarrhythmic, and cytoprotective effect. The direct action is shortlasting; it protects from myocardial ischemia and arrhythmias, at least partly, by its vasodilating, antiaggregatory, and "membrane-stabilizing" effects. The delayed, long-lasting PgI2-induced protection from postocclusion, reperfusion- and ouabain-arrhythmias is dose- (optimal 50 micrograms/kg) and time- (optimal 48 h after treatment) dependent. Its mechanism is probably based on a 7-oxo-PgI2 induced increase in the activity of Na/K-ATP-ase, and further, on a reduced sensitivity to beta-adrenergic agonists and to changes at the cardiac membrane level, resulting in a prolongation of the action potential duration and the effective refractory period.

Animals↗
PubMed1989

7-oxo-PgI2 induced late appearing and long-lasting electrophysiological changes in the heart in situ of the rabbit, guinea-pig, dog and cat.

We have previously observed a long-lasting antiischemic and antiarrhythmic effect induced by prostacyclin (PgI2) or its stable analogue, 7-oxo-PgI2-ephedrine salt in dogs subject to local myocardial ischemia. This protection appeared when the vasodilating and platelet aggregation inhibiting effect of PgI2 or its analogue was over and persisted even 72 h after treatment. We have also found that short incubation with 7-oxo-PgI2 may induce a long-lasting prolongation of the action potential duration and of the effective refractory period in the isolated rabbit papillary muscle preparation without affecting the membrane potential or the rate of rise of the action potential. Our present experiments have shown a 7-oxo-PgI2 induced, dose-dependent prolongation of the ventricular functional refractory period in conscious rabbits and anesthetized dogs, as well as an increase of the QT interval in the ECG in both species and also in conscious guinea-pigs. In all three species 50 micrograms/kg i.m. dose proved to be optimal, evoking maximal effect 48 h after treatment. In conscious rabbits this pre-treatment prevented the train of non-stimulated extra beats induced by premature stimuli. Furthermore it also prevented widening of the QRS complex appearing in non-treated controls after programmed stimulation. Pre-treatment significantly increased electrical fibrillo-flutter thresholds in the auricles and ventricles of anesthetized cats. These electrophysiological changes seem to be closely related to the 7-oxo-PgI2 induced, late appearing and long-lasting protection from ischemic and reperfusion arrhythmias.

Action Potentials↗
PubMed1989

[Analytic measurement of the solubility of the enamel surface exposed to acid and morphometric study of the resulting erosion in rat incisors treated with aluminum].

Their method of examination is based on the area analytical examination of scanning electromicroscopic photographs made of the enamel surfaces corroded with acid. By means of their method the area distribution of the enamel surfaces has been determined on which no detectable changes were formed after the acid action. The results obtained that way have also been compared with the results of analytical measurements. Their examinations were performed on uppar incisors of rats treated with aluminium.

Acid Etching, Dental↗
PubMed1988

On the 7-oxo-PgI2 induced lasting protection against ouabain arrhythmias in anesthetized guinea pigs.

In our earlier experiments prolonged administration of the stable PgI2 analogue: 7-oxo-PgI2 ephedrine salt to dogs afforded a long-lasting protection against coronary occlusion induced ischemia as well as against postocclusion and reperfusion arrhythmias. In the present experiments we wanted to clear, whether this prolonged protective action is present in other types of arrhythmia, which are not due to ischemia. The ouabain-arrhythmia seemed to be suitable for elucidation of this question. Therefore guinea pigs were pretreated with 50 micrograms/kg i.p. 7-oxo-PgI2 and 24, 48, 72 and 96 hrs after treatment anesthetized with 35 mg/kg sodium pentobarbitone. To prevent ouabain bradycardia, 0.4 mg/kg atropine was administered i.p. Ouabain was applied by intermittent infusion technique i.e. an initial infusion for 5 minutes of a total dose of 60 micrograms/kg into the right jugular vein was followed after a 25 minutes interval by infusions of 30 micrograms/kg for 2.5 minutes every 10 minutes until cardiac arrest. The ouabain induced rhythm disturbances appeared in the following order: Anomalies in T wave morphology, ventricular or nodal extrasystoles, atrio-ventricular and intraventricular conduction disturbances, ventricular tachycardia, ventricular fibrillation and finally cardiac arrest. If 50 micrograms/kg i.p. 7-oxo-PgI2 was given to ouabain-intoxicated animals at the appearance of the first extrasystole a transient aggravation of this arrhythmia developed. In 7-oxo-PgI2 pretreated animals the total amount of ouabain necessary to induced rhythm disturbances was markedly elevated, the appearance of the various arrhythmias significantly delayed. Maximal protective effects were seen 48 hrs after the administration of 50 micrograms/kg 7-oxo-PgI2.

Animals↗
PubMed1988

The importance of closed bladder irrigation in prostatectomy.

Closed bladder irrigation in transvesical prostatectomy is an important factor in arresting bleeding and preventing or diminishing bacterial infection. A bladder irrigation of appropriate intensity may ensure that the blood clots be removed rapidly from the bladder and thereby the formation of larger clots and bladder tamponade can be avoided. The bacteriological examination of the eluents of 82 patients revealed that the longer the patient is maintained on a catheter, the longer bacteriuria and pyuria will persist. Two days are considered by the authors to be the optimal time of maintaining a closed bladder irrigation.

Bacteriological Techniques↗
PubMed1988

7-oxo-PGI2 induced late appearing and long lasting antiischaemic and antiarrhythmic action in dogs.

In our earlier experiments administration of the stable PGI2 analogue: 7-oxo-PGI2-ephedrine salt to dogs resulted in a late-appearing and long-lasting protection from coronary ligation induced ischaemia as well as from postocclusion and reperfusion arrhythmias. Objective of the present study was to evaluate the extent and duration of antiischaemic and antiarrhythmic action induced by a single dose 50 ug/kg i.m. 7-oxo-PGI2 in dogs subjected to myocardial ischaemia evoked by left anterior descending coronary artery (LAD) ligation at different intervals (2, 6, 24, 48, 72 hours and 2 weeks) after treatment. After anaesthesia and thoracotomy the electrophysiological parameters - sinus cycle length (SCL), corrected sinus node recovery time (CSNRT), atrial and ventricular functional refractory period (AFRP, VFRP), and atrio-ventricular effective refractory period (A-V ERP) - were determined by means of computer controlled programmed electrical stimulation. Then the animals were subjected to LAD occlusion for 25 minutes and subsequent reperfusion. 7-oxo-PGI2 pretreatment considerably protected against myocardial ischaemia i.e. there was significant reduction in ST-segment elevation, the number of extrasystoles (ES) and the incidence of ventricular fibrillation (VF). The antiischaemic action started 2 or 6 hours after the drug administration, however, the maximal protection - indicated by the diminution of ischaemic epicardial ST-segment elevation - as well as the most striking reduction in postocclusion and reperfusion arrhythmias could be observed 48 hours after the single dose of 7-oxo-PGI2 and in case of two weeks treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Verapamil in a new model of severe local myocardial ischaemia due to combined coronary occlusion and stenosis.

The effect of verapamil was studied in a new canine model of local myocardial ischaemia. In this model in addition to the critical construction of the left circumflex coronary artery, the left anterior descending branch was suddenly occluded. Experiments were performed in the anaesthetized, thoracotomized and artificially respired dog. The model represents a severe form of myocardial ischaemia and mimics the clinical situation in which usually more than one coronary artery is involved in the stenotic process. Verapamil (0.15 mg kg -1 i.v.) moderated the extent of the ischaemic changes (indicated by the ST segment elevation in the epicardial and endocardial ECG) as well as their consequences e.g. the incidence and severity of early postocclusion and reperfusion arrhythmias. This beneficial effect was probably due to the drug-induced favourable haemodynamic action (reduction of left ventricular end-diastolic pressure and slight increase in left ventricular dP/dtmax) and to the electrophysiological effects (e.g. decreased inhomogeneity of electrical activation, diminution of extrasystolic activity) and blood flow changes (enhanced blood supply to the ischaemic subepicardium).

Animals↗