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Biomedical subjects

C Advenier

Publications and source records attributed to C Advenier.

At least 235 records · Page 13Linked to original sources
PubMedDate not supplied

[Inhibition of uterine contractions: new in vitro pharmacological approaches on the pregnant human myometrium].

The aim of this study was to evaluate the in vitro effects of phosphodiesterase 4 inhibitors (PDE4I) and their combination with salbutamol (beta 2-adrenoceptor agonist) on spontaneous contractions and to investigate by in vitro and biochemical studies and analysis of mRNA expression the presence of beta 3-adrenoceptor in human near-term myometrium. Rolipram, RP 73401 and Ro 20-1724 (PDE4I) inhibited spontaneous myometrial contractions (Emax approximately 100 per cent; pD2 approximately 6.80 for the two first and 6.31 for Ro 20-1724). Rolipram 10(-8) M potentiated the response to salbutamol (Emax = 88 per cent vs. 40 per cent and pD2 = 6.93 and 6.36 with or without rolipram respectively). SR 59119A, a beta 3-adrenoceptor agonist, was more efficient than salbutamol in inhibiting the contractions (Emax 52 per cent and 27 per cent respectively, p < 0.05) but they both induced a significant increase of cAMP production. In both functional and biochemical studies, SR 59119A was only antagonized by the beta 3-adrenoceptor antagonist SR 59230A. The beta 3-AR mRNA was positively expressed in myometrium preparations in a reverse transcription polymerase chain assay. In conclusion, phosphodiesterase 4 inhibitors alone or combined with beta 2-adrenoceptor agonists and beta 3-adrenoceptor agonists might have potential interest as tocolytic agents.

4-(3-Butoxy-4-methoxybenzyl)-2-imidazolidinone↗
PubMedDate not supplied

[Diffusion of minocycline in pulmonary tissue].

The penetration of minocycline into lung tissue was evaluated in 14 patients about to undergo excision of the lung for cancer. The patients received minocycline orally in doses of 100 mg twice a day for 3 days, the 100 mg in the morning of the operation day. Minocycline concentrations were measured in plasma samples taken before surgery and in the lung tissue resected. The mean tissue/plasma concentration ration was 3.17 +/- 0.41 (range: 1.5 to 7.48). The same ratios were obtained in peritumoral and tumoral tissues. These results indicate that minocycline penetrates well into tissues.

Adenocarcinoma↗
PubMedDate not supplied

[Influence of surgical biliary pathology on the diffusion of ceftriaxone in the biliary tract].

Ceftriaxone is a third generation cephalosporin remarkable for its wide distribution in the biliary tract. The purpose of this study was to determine whether biliary tract pathology, as observed during surgery, had an influence on this distribution. 52 patients about to be operated upon and presenting with a high risk of bile infection received a single 1 or 2 g dose of ceftriaxone administered intravenously over 20 min during the hour that preceded surgery. Samples of blood and of bile from the gallbladder (GB) and the common bile duct (CBD), as well as specimens of the GB wall were taken during the operation. In patients whose GB was normal at laparotomy (apart from stones) ceftriaxone concentrations in bile and GB wall were 10-25 and 2 times respectively higher than in plasma. In patients with a grossly distended but not infected GB (hydrocholecystis) ceftriaxone levels were high in CBD bile but null in GB bile and only one-quarter to one-half of plasma levels in GB wall. In patients with stones in the CBD or inflamed GB wall ceftriaxone levels were high in bile (although lower than in cases with normal GB) and similar to plasma levels in GB wall. When malignant pancreatic lesions were present ceftriaxone concentrations could not be measured in both GB and CBD bile but reached 50% of plasma concentrations in GB wall.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMedDate not supplied

Effects of six beta-blockers on the isolated guinea-pig trachea.

The effects of six beta-blocking agents (propranolol, metoprolol, atenolol, pindolol, medroxalol and labetalol) selected on the basis of their intrinsic sympathomimetic properties, membrane-stabilizing activities and selectivity for beta 1-adrenoceptors were investigated on the isolated guinea-pig trachea. Tracheal spirals were either allowed to remain under resting tension or were precontracted with histamine 2 X 10(-6) M or 2 X 10(-5) M. Pindolol, medroxalol and labetalol exerted a moderate relaxant effect on tracheal muscle. This effect was inhibited by propranolol, but not significantly modified by indomethacin. Propranolol and metoprolol exerted a moderate contracturant effect on the preparations. The effect was inhibited by indomethacin but not by FPL 55712. Atenolol had no effect on tracheal muscle. This in vitro study provided data concerning two properties of beta-blockers--intrinsic sympathomimetic and membrane-stabilizing activities--which are involved in the bronchomotor response to these drugs in vivo.

Adrenergic beta-Antagonists↗
PubMedDate not supplied

Alpha-blocking properties of idazoxan (170150 or RX 781094) and its stereoisomers: applications to bronchomotricity.

The alpha 1- and alpha 2-adrenolytic properties of idazoxan and its stereoisomers were studied on the bronchopulmonary system of unanaesthetized guinea-pigs by testing the effects of these compounds on the phenylephrine-acetylcholine and clonidine-acetylcholine interactions. Idazoxan and its (+) and (-) stereoisomers did not significantly modify the protection exerted by phenylephrine against acetylcholine modify the protection exerted by phenylephrine against acetylcholine (ACh)-induced bronchoconstriction. Idazoxan and its (+) and (-) stereoisomers reduced the potentiation of ACh bronchoconstriction induced by clonidine, but (+) idazoxan was more potent than (-) and (+/-) idazoxan. As (+) idazoxan appeared to be a preferential alpha 2 central adrenoceptor blocking agent, these results seem to indicate that the site of action of clonidine in bronchomotor responses is the central nervous system.

Acetylcholine↗
PubMedDate not supplied

[Effect of verapamil, nicardipine and disodium cromoglycate on the bronchoconstrictor effects of histamine].

The effects of nicardipine, verapamil and sodium cromoglycate (SCG) on the increase in pulmonary airway resistance (Raw) and decrease in pulmonary dynamic compliance (C.Dyn.) induced by histamine (Hist) (3 and 30 micrograms x kg-1, i.v.) and acetylcholine (ACh) (3 and 30 micrograms x kg-1, i.v.) were investigated in anaesthetized guinea-pigs. The effects of these three agents on the contractile effects of Hist and ACh were tested on isolated tracheal preparations of the guinea pig. Nicardipine (0.3 and 1 mg . kg-1, i.v.) and verapamil (1 mg . kg-1, i.v.) as well as SCG (3 and 10 mg . kg-1, i.v.) partially but significantly inhibited the effects of Hist on Raw. These substances had no effect on Hist-induced decrease in C.Dyn. Nicardipine and verapamil had no effect on ACh-induced bronchoconstriction in vivo. SCG partially but significantly inhibited the effects of ACh (30 micrograms . kg-1) on Raw. In concentrations higher than 3 x 10(-6) M, nicardipine and verapamil inhibited the contractile effects of Hist and ACh on guinea-pig isolated trachea. SCG had no effect on this preparation. The results suggest that nicardipine, verapamil and SCG partially reduce the component of bronchoconstriction associated with stimulation of irritant receptor by Hist. However, the site and mechanism of action of Ca++-entry antagonists remain uncertain.

Acetylcholine↗
PubMedDate not supplied

Effects of nifedipine, propranolol, adenosine and caffeine on benzodiazepines induced hyperglycaemia.

This study shows that diazepam (20 mg/Kg) and clonazepam (2 mg/Kg) administered intraperitoneally to 36 hour-fasted rabbits induce a significant (p < 0.05) hyperglycaemia 30 min. after administration. It also shows that the hyperglycaemic action of these benzodiazepines is significantly potentiated by nifedipine (10 mg/Kg) and inhibited by adenosine (1 mg/Kg), caffeine (40 mg/Kg) and propranolol (20 mg/Kg). The most pronounced inhibitory effect was that exerted by propranolol (p < 0.05). It is suggested that diazepam and clonazepam induced hyperglycaemia may be due to the release of hyperglycaemic hormones including adrenaline responsible for an increase of 3' 5' cAMP since the action of these benzodiazepines is inhibited by propranolol.

Adenosine↗