Search PubMed⌕ Search

Biomedical subjects

K Bouzouita

Publications and source records attributed to K Bouzouita.

30 records · Page 2Linked to original sources
PubMed1989

[ORL cancer in the child. Histologic and topographic distribution. Therapeutic indications (apropos of 380 IGR cases 1975-1987)].

Three-hundred and eighty cases of head and neck cancers in children, observed in the Pediatric Department of the Institut Gustave Roussy over a 12-year period are reported. The authors study the clinical presentation of these cancers (primary site and histological distribution) and consider the major prognostic factors. A brief reminder is then given of the therapeutic indications for the main tumors observed.

Child↗
PubMed1985

Efficacy of disopyramide in comparison with verapamil and propranolol in the prevention of acetylcholine-induced atrial fibrillation in the dog.

The efficacy of verapamil and propranolol was studied in comparison with disopyramide on the atrial fibrillation experimentally induced in the dog heart in situ by electrical stimulation combined with intra-aortic injection of acetylcholine (ACh). After reducing the amplitude and duration of the monophasic action potential (MAP) and the duration of the effective refractory period (ERP) of the atrial contractile fibres, ACh lowered the fibrillation threshold (FT), and, when fibrillation had been elicited, it accelerated the fibrillation rate (FR). Verapamil and propranolol failed to prevent atrial fibrillation: they did not counteract any of the alterations in the electrophysiological properties of the atrial contractile fibres due to ACh. In contrast, disopyramide, at doses within the therapeutic range, prevented fibrillation. The fibrillation threshold, which fell from 50 mA to 1 mA in the presence of ACh, was restored to control values by disopyramide. Disopyramide also antagonized the reduction in amplitude of MAP caused by ACh before the triggering of fibrillation and the reductions by ACh of the durations of MAP and ERP. Disopyramide first slowed FR, in association with an increase in amplitude of fibrillation waves and a tendency to synchronous activity, and ultimately terminated the fibrillation.

Acetylcholine↗
PubMed1984

Potentiation by hypokalemia of the effects of acetylcholine on the canine heart in situ.

In the heart in situ of vagotomized dogs, atrioventricular conduction was studied by the His bundle potential recording, sinus rate continuously registered and the effective refractory period (ERP) of the atrial muscle measured by the extrastimulus method. The modifications induced by the acute lowering of plasma potassium concentration from 3.5 to 2.0 mmol/l obtained by hemodialysis appeared to be similar to those due to parasympathetic stimulation and the effects of hypokalemia and acetylcholine (ACh) on the atrioventricular (A-V) and sinoatrial nodes as well as on the atrial contractile tissue gave rise to potentiation. Intraaortically injected near coronary ostia in a dose lower than liminal dose, ACh enhanced to a large extent all the phenomena elicited by hypokalemia, since the variations respectively observed under the influence of hypokalemia alone and the combination of hypokalemia and ACh were as follows: lengthening of conduction time in the A-V node by 100 and 180%, reduction of sinus rate by 10 and 20%, shortening of the atrial ERP by 20 and 40%.

Acetylcholine↗
PubMed1983

Enhancement by Ca2+ ions of cholinergic effects on the canine heart in situ.

The effects of Ca2+ ions were studied on the canine heart in situ, submitted to vagal influence or not. In addition to heart rate, conduction time was determined separately in atrial muscle, atrioventricular node and His-Purkinje system by means of His bundle potential recording and the effective refractory period (ERP) measured in atrioventricular node, atrial and ventricular muscle according to the extrastimulus method. In the presence of acetylcholine (ACh) released by vagal endings, an increase in plasma calcium concentration from 2.40 to 4.12 mmol/l, acutely induced by the infusion of calcium chloride, elicits the following alterations: slowing down of sinus rate, lengthening of conduction time in atrioventricular node without change of this time in atrial muscle and His-Purkinje system, prolongation of atrioventricular node ERP, but notable decrease of atrial muscle ERP and slight decrease of ventricular muscle ERP. These effects are similar to those of ACh:Ca2+ ions probably enhance the responsiveness to ACh.

Acetylcholine↗
PubMed1983

Blockade by verapamil of cholinergic effects on atrial specialised tissue in the anaesthetised dog.

The effects of verapamil were studied in anaesthetised dogs administered dextromoramide intrathecally to provide background vagal tone. Measurements were made of spontaneous heart rate, and, in paced hearts, of conduction times in atrial muscle, the atrioventricular node (A-V node) and His-Purkinje system by means of His bundle potential recording. The effective refractory period (ERP) of A-V node was measured by the extrastimulus method. In atropinised and vagotomised animals, verapamil reduced sinus rate and increased A-V nodal conduction time. In dogs high vagal tone after dextromoramide, however, verapamil increased sinus rate and reduced A-V nodal ERP. After dextromoramide alone, A-V block was observed at an atrial pacing rate of 150 beats X min-1, but after verapamil 1:1 A-V conduction was restored. The decrease in conduction velocity in the A-V node due to ACh was neither attenuated nor enhanced by verapamil.

Acetylcholine↗
PubMed1983

Study of the ventricular antifibrillatory effects of calcium channel blocking agents in comparison with lidocaine on canine normal heart in situ.

The ventricular antifibrillatory effects of two calcium channel blocking agents have been studied by determining fibrillation threshold several times in the course of an experiment on dogs placed under total cardiopulmonary by-pass to avoid the impairment of the myocardium properties subsequent to the interruption of blood circulation. These drugs were used in therapeutic or even higher doses (verapamil 0.40 mg.kg-1, diltiazem 0.60 mg.kg-1). They failed to modify fibrillation threshold significantly, and did not influence fibrillation rate or the effective refractory period of contractile fibres. Lidocaine, on the contrary, under the same experimental conditions, induced a dose-dependent rise in fibrillation threshold of up to nearly 200%, correlated to a fall in fibrillation rate and a prolongation in effective refractory period.

Animals↗
PubMed1982

Effects of hypokalemia on the various parts of the conduction system of the dog heart in situ.

The effects of hypokalemia were studied on the various parts of the conduction system by means of His bundle potential recording in the heart of vagotomized dogs. Plasma potassium concentration was lowered by extracorporeal dialysis, precautions being taken against the simultaneous impairment of other parameters, especially humoral. In order to make sure that the changes in atrioventricular conduction observed were due to hypokalemia, a control series of experiments was carried out, under strictly identical conditions except that the dialysis fluid was not devoid of potassium. The following alterations were observed during the lowering of potassium concentration from 3.2 to 1.6 mmol/l: atrioventricular node conduction time (AH interval) increased steadily up to 250% of control values; conduction time in atrial contractile tissue (SA interval) and His Purkinje system (HV interval) exhibited variations much later and much smaller; conduction time in ventricular contractile tissue was not significantly affected; effective refractory period (ERP) of atrial muscle, initially the longest in ERPs of conduction system in vagotomized animals, was shortened by about 20%. The mechanism of all these alterations is discussed.

Acetylcholine↗
PubMedDate not supplied

[Ear myiasis. Two case reports].

The authors report two cases of aural myiasis. This pathology rarity induced us to search after epidemiologic, clinic and therapeutic peculiarity of this parasitical disease.

Adult↗
PubMedDate not supplied

Influence of the restoration of vagal tone by intracisternal injection of dextromoramide on the cardiac effects of the antiarrhythmic drugs.

The effects of four antiarrhythmic drugs, quinidine, procainamide, amiodarone and verapamil were studied on sinus rate, conduction time and, when possible, effective refractory period (ERP) in atrioventricular node (AV node), and finally atrial muscle ERP. This study was made under two types of conditions, vagal tone being absent or present after restoration in the anesthetized dog by a new technique, the intracisternal injection of dextromoramide. Quinidine and procainamide which tend to slow down sinus rate and conduction in the former case accelerate them considerably in the latter by opposing the effects of acetylcholine released by vagal endings. The prolongation of atrial ERP also induced by these drugs results from both this process and their own capacity. Amiodarone and verapamil, usually responsible for bradycardia, notable delay in AV node conduction and lengthening of AV node ERP are, however, liable to elicit opposite effects, especially amiodarone when vagal tone is very high. The reduction of vagal influence is, in the case of these drugs, the only factor in the prolongation of atrial ERP. In any case, the response of both specialized and common tissue of the heart to antiarrhythmic drugs should not be interpreted unless the degree of vagal tone is known.

Amiodarone↗