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Biomedical subjects

B Pourrias

Publications and source records attributed to B Pourrias.

At least 37 records · Page 2Linked to original sources
PubMed1981

Synthesis and antiarrhythmic activity of new benzofuran derivatives.

Various 5-aminobenzofuran derivatives were prepared from khellin and screened intravenously in the dog for their potential antiarrhythmic activity against ouabain-induced ventricular arrhythmia and in the Harris test. From systematic structural variations it was found that two methoxy groups in positions 4 and 7 on the benzofuran ring, a tertiary aminoethoxy side chain in position 6, and a N-methylurea group in position 5 led to the most active compounds. These were then tested orally in the Harris test in the dog. The two long-acting derivatives N-[4,7-dimethoxy-6-(2-pyrrolidinoethoxy)-5-benzofuranyl]-N'-methylurea (8j) and N-[4,7-dimethoxy-6-(2-piperidinoethoxy)-5-benzofuranyl]-N'-methylurea (8m) showed advantages when compared to quinidine and disopyramide and have been selected for further studies.

Animals↗
PubMed1978

Vascular and myocardial effects of mecinarone.

The effects of mecinarone on the contractions induced by noradrenaline, potassium and calcium were studied with the isolated aorta and central artery of the rabbit ear. In our experimental conditions mecinarone was found to act as a competitive antagonist of calcium. It preferentially inhibited the noradrenaline-evoked contraction induced in the rabbit ear artery and had a smaller effect on the extracellular calcium-induced contraction of depolarized arterial smooth muscle. In the isolated guinea pig heart, mecinarone produced a reversible decrease in the rate of rise of the ascendant phase of the action potential without significantly changing the resting potential. In hearts inactivated by depolarisation, mecinarone inhibited the contractions restored by isoproterenol without suppressing the calcium action potential. These results suggest that the mode of action of mecinarone is different from that of verapamil or nifedipine but is comparable to that of chlorpromazine, although mecinarone has no sedative effect.

Action Potentials↗
PubMed1975

Pharmacological study of a new substance, mecinarone.

Mecinarone, a benzofuranic chalcone, shows considerable vasodilating activity on the peripheral and cerebral circulation. The intramuscular irrigation is thus improved and the cerebral blood supply increased. This vasodilating activity is accompanied by only a slight drop in the systemic arterial pressure and occurs without cardiac depression. Mecinarone has also antibradykinin, antiserotonin and antiaggregation properties which added to the vasodilating activity, greatly increase its pharmacological interest.

Administration, Oral↗
PubMedDate not supplied

Comparison between the ventricular fibrillation thresholds of spontaneously hypertensive and normotensive rats--investigation of antidysrhythmic drugs.

Induction of ventricular fibrillation by intraventricular electric pulses is achieved with weaker currents in spontaneously hypertensive rats (SHR) than in normotensive rats of the Wistar-Kyoto (WKY) or Sprague-Dawley (SD) strains. The ventricular fibrillation threshold (VFT) is stable with time in SHR but not in WKY. Investigation of antidysrhythmic agents in SHR showed that most substances with membrane-stabilizing properties increase the VFT. There was no correlation between the elevation of VFT and the decrease in heart rate induced by the substances studied. Determination of the VFT in SHR may be useful for the screening of compounds with membrane-stabilizing properties.

Animals↗
PubMedDate not supplied

The chronotropic effect of adenosine and ATP in dogs. The antagonism by theophylline.

We analyzed the action of adenosine and adenosine triphosphate (ATP) on the chronotropism of the dog heart in situ. The compounds were administered either intravenously (i.v.) after bivagotomy and propranolol treatment, or intracoronary (i.c.) in the sinus node blood supply. Under these conditions the intervention of reflex reactions was eliminated, and a constant and dose-dependent negative chronotropic effect was obtained. From the dose-response curves the relative potencies of ATP and adenosine were calculated, and found to be similar for both routes of administration (potency ratio 0.77 (0.72-0.82) by i.v. administration, and 0.52 (0.36-0.78) by intracoronary administration). The effect was also mimicked by 2-chloroadenosine, (a long acting P1 agonist), and by 5'-adenylyl (beta, gamma-imido) diphosphonate, a non-hydrolysable ATP analog. The chronotropic effect of ATP and adenosine were not prevented by 1 mg/kg atropine intravenous. Theophylline, at 3 mg/kg i.v., shifted the dose-response curves of i.v. ATP and adenosine to the right, suggesting a competitive antagonism. At a dose of 6 mg/kg theophylline, the effects of i.c. adenosine were competitively blocked. Theophylline also antagonized, in a competitive manner, the hypotensive effect of the i.v. administration of both compounds. Our results suggest that the chronotropic effect of purine compounds in anaesthetized animals could be brought about by a specific purinergic theophylline-sensitive mechanism and not by direct vagal activation.

Adenosine↗
PubMedDate not supplied

[Comparison of the effects of regional ischemia and of reperfusion on the hypertrophied heart of spontaneously hypertensive rats and the heart of Wistar-Kyoto rats with isolated perfused heart via the left atrium. Effects of lidocaine, propranolol and verapamil].

1. A comparative study between the effects of ischemia and reperfusion on the hypertrophied heart of spontaneously hypertensive rat (SHR) and on the heart of Wistar-Kyoto (WKY) was carried out in working heart conditions. 2. The decrease of coronary flow induced by a coronary occlusion had an equal magnitude in the two groups. In the SHR group, the aortic output became null in 40% of the cases, whereas this effect was never seen in WKY group. 3. In reperfusion conditions, the recovery of haemodynamic values was slower in SHR group. The release of LDH and the rhythmic disturbances were also increased. 4. The perfusion of SHR hearts by lidocaine (4.3 10(-5) M), propranolol (7.7 10(-6) M) and verapamil (1.1 10(-7) M) decreased significantly the heart rate and the aortic output. 5. When these substances were added to the perfusion medium, the deleterious effects of reperfusion were greatly reduced. Aortic output recovered more quickly than his basal values and the enzymatic leakage was decreased. None of the hearts fibrillated after lidocaine and propranolol. Ventricular fibrillation continued in 14% of cases after verapamil compared to 80% of cases in the control group.

Animals↗
PubMedDate not supplied

[Diagnosis of chyliferous blockage by the hyperlipidemia test (author's transl)].

In our hyperlipidemia test, the total lipids curve, a plateau without a postprandial peak, allows an easy diagnosis of the chyliferous blockage. The malformation of chyliferous vessels produces the congenital forms: exsudative enteropathy, chyloperitoneum, spontaneous chylothorax, chylous cyst of the mediastinum, reflux of chyle in the pulmonary lymphatics, lymphoedema with chyle reflux in the lymphatics of the leg and chyluria. The acquired forms comprise the post-infectious sclerosis of the intestinal lymphatics and the neoplastic invasions of the mesenteric lymph nodes. The optical density curve brings some informations for a better understanding of lipid's absorption.

Adult↗