Search PubMed⌕ Search

Biomedical subjects

C Harvengt

Publications and source records attributed to C Harvengt.

At least 55 records · Page 3Linked to original sources
PubMed1990

Effect of cimetidine on the pharmacodynamics, pharmacokinetics and biotransformation of a single oral dose of alpidem.

Alpidem is a new imidazopyridine derivative acting as an anxiolytic which may be prescribed with H2 receptor antagonists in patients with peptic ulcer. An open trial design (cimetidine, 1 g daily for 22 days) was carried out in eight healthy subjects. Alpidem, 50 mg was administered orally at 09:00 prior to any treatment and on days 2 and 18 of the cimetidine treatment period. Antipyrine clearance was also determined before and on day 21. Under these experimental conditions, the inhibitory effect of cimetidine on the cyt. P-450 monooxygenase system has been demonstrated (reduced clearance of antipyrine and its three main urinary metabolites) but the plasma pharmacokinetics of alpidem and its three main plasma metabolites did not appear to be modified. Alpidem induced no sedative effect but there was an insignificant trend to impair slightly the psychometric tests 1 h post-drug by the combination with cimetidine. Pharmacokinetic and pharmacodynamic evaluations did not show significant interactions with cimetidine following alpidem 50 mg administration.

Administration, Oral↗
PubMed1990

Pharmacokinetic profile and bioavailability of a new galenic formulation of ticlopidine.

The bioavailability of a new film-coated tablet of ticlopidine hydrochloride was compared in 12 healthy male subjects to that of the older sugar-coated tablet. Plasma levels of ticlopidine were measured by gas-liquid chromatography up to 120 h after a single 500 mg dose of each preparation. Drug intake was separated by a four-week interval. No statistically significant differences could be found between the pharmacokinetic parameters for these two preparations. Bioequivalence was confirmed when applying the test of Westlake to the area under the curves (calculated difference: 8.3%; upper limit: 20%). No unwanted effect was reported during the study.

Adult↗
PubMed1990

[Sensitivity and specificity of the determination of urinary catecholamines and their acid metabolites in the diagnosis of neuroblastoma in children].

A retrospective comparison of urinary excretion of norepinephrine, epinephrine, dopamine and/or their acidic metabolites, HVA and VMA, in 36 children with neuroblastoma versus 360 hospitalized children without neuroblastoma showed a sensibility of 72% and a specificity of 98% for HVA and 80% and 97% for VMA respectively. Consequently, the sensibilities and specificities of these 2 determinations confirm their useful purpose for the biochemical diagnosis of neuroblastoma in preference to the determinations of norepinephrine, epinephrine and dopamine.

Adolescent↗
PubMed1989

An improvement of Barter's method for assaying plasma cholesterol ester transfer activity: experimental and clinical applications.

The use of a discontinuous density gradient and of a vertical rotor to separate plasma lipoproteins are modifications of Barter's described method for assaying cholesteryl ester transfer activity (CETA) in plasma. The original feature of our approach is the fast preparation of the labeled substrate by a physiologic-like process, which renders the assay easy and suitable for measurement of this activity in both man and animals.

Adult↗
PubMed1989

Hypotriglyceridemic action of omega-3 fatty acids in healthy subjects does not occur by enhanced lipoprotein lipase and hepatic lipase activities.

Single blind administration of EPA-rich omega-3 fatty acids at 3 dose levels of 3g, 6g and 12g/d (each dose lasting 3 weeks was separated by 2 weeks on placebo) lowered plasma TG levels and lecithin cholesterol acyltransferase-molar esterification rate (LCAT-MER) activity (6.12g/d). Lipolytic enzymes activity (LPL and HL) remained unchanged at these doses. Fat malabsorption was unlikely because of unmodified plasma beta-carotene, retinol and alpha-tocopherol levels.

Adult↗
PubMed1989

Influence of rifampicin, phenobarbital and cimetidine on mixed function monooxygenase in extensive and poor metabolizers of debrisoquine.

The effect of enzyme induction by rifampicin and phenobarbital and enzyme inhibition by cimetidine on the hepatic mixed-function monooxygenase (MFO) was investigated in 11 non-smokers, healthy male volunteers. Five were classified as extensive metabolizers (EM) of debrisoquine and 6 as poor metabolizers (PM). Rifampicin (600 mg/day), phenobarbital (100 mg/day) and cimetidine (1.2 g/day) were given for 8, 14 and 4 days, respectively. In PM on rifampicin, the debrisoquine metabolic ratio (MR) was significantly reduced, even reaching a value less than 12.6 in 2 subjects but on phenobarbital and cimetidine, the MR was not significantly modified. In PM on rifampicin and phenobarbital, the urinary excretion of 6 beta-hydroxycortisol was significantly enhanced but not in EM on these drugs. In both groups on cimetidine, salivary antipyrine half-life was lengthened and on rifampicin, it was shortened. In EM and PM on cimetidine, the total oral clearance of antipyrine was lowered but on rifampicin it was solely increased in PM. Regarding the metabolic clearance to the three main urinary antipyrine metabolites, that of norantipyrine (NORA) was significantly increased in PM on rifampicin. In PM on cimetidine, the metabolic clearance of NORA and hydroxymethylantipyrine (HMA) was reduced but in EM that of hydroxyantipyrine was additionally decreased. In PM on rifampicin, the induction of the hepatic mixed-function oxidase system, assessed by the urinary excretion of 6 beta-hydroxycortisol, the salivary antipyrine half-life and total oral clearance and the metabolic clearance of urinary NORA, were shown. On the other hand in PM, cimetidine, a probe drug used for inhibition of the MFO system, made it impossible to distinguish PM from EM.

Adult↗
PubMed1989

Simvastatin (MK 733) in heterozygous familial hypercholesterolemia: a two-year trial.

Simvastatin (MK 733), a new competitive inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase, given in daily doses of 20 mg and 40 mg for 104 weeks, has been shown to lower the serum total cholesterol and low density lipoprotein cholesterol level by more than 30% and the serum apoprotein B level by 20% in 19 adult patients with heterozygous familial hypercholesterolemia. A slight but non-significant increase of high density lipoprotein cholesterol levels was shown throughout the trial with significant elevation of the serum apoproteins AI and AII only observed at week 52. Mild and transient clinical or biochemical (increases of creatine phosphokinase and transaminases) side effects, observed in some patients, did not necessitate the withdrawal of the medication. Full ophthalmological examinations did not reveal ocular disturbances, particularly no apparent increase of lens opacities, during the trial. Simvastatin seems to be an effective and safe drug as monotherapy in the treatment of heterozygous familial hypercholesterolemia.

Adult↗
PubMed1988

Influence of repeated administration of cimetidine on the pharmacokinetics and pharmacodynamics of adinazolam in healthy subjects.

Adinazolam is a new triazolobenzodiazepine bearing an alkyl-amino side chain. A cross-over double-blind placebo controlled study was carried out in 12 healthy volunteers, in order to check the possible interaction between cimetidine and adinazolam after repeated co-administration. Cimetidine or placebo were given during 17 days. Beginning on Day 8 of each treatment, adinazolam was given in the increasing doses following sequence of doses for 3 days: 10 mg b.i.d., 20 mg b.i.d. and 20 mg t.i.d. A pharmacokinetic and pharmacodynamic study was performed on the third day at each dose. A wash-out of three weeks was included between the two treatments. Cimetidine increased significantly the AUC values of both adinazolam and N-desmethyladinazolam, reduced the oral clearance of adinazolam, and prolonged adinazolam's half-life. The digit symbol substitution test was significantly affected at each dose level while the manual dexterity was marginally impaired by adinazolam plus cimetidine. Saftee-up interview and Clyde mood scale indicated an increased sedation under adinazolam plus cimetidine in four subjects.

Adult↗
PubMed1988

Possible interactions between zolpidem, a new sleep inducer and chlorpromazine, a phenothiazine neuroleptic.

The combined use of a hypnotic and a neuroleptic is a rather frequent situation, encountered especially in the psychiatric sphere. We therefore tested zolpidem and chlorpromazine in six healthy subjects by using a double-blind latin square design. All of them received single doses of 20 mg zolpidem (ZOL), 50 mg chlorpromazine (CPZ) and the combination of ZOL + CPZ. The medication was given as a single dose in the morning and each treatment being separated by a 1-week interval. Zolpidem produced moderate to severe sedation varying according to the subjects. Psychometric performances (manual dexterity, Stroop test), alertness and psychomotricity (visual analogue scales) were reduced up to 3 h after drug intake. Chlorpromazine alone did not have much effect. Combined administration of ZOL and CPZ was rather more effective than ZOL alone. The pharmacokinetics of ZOL or CPZ remained unchanged except for the elimination half-life of CPZ, which increased significantly when administered along with ZOL. No other pharmacodynamic or pharmacokinetic interaction between ZOL and CPZ was evident. The fact that the ZOL and CPZ combination accentuated the pharmacodynamical effects can be explained to result from the summation of each of their own pharmacological effect.

Adult↗
PubMed1988

Changes in lipoprotein composition in women receiving two low-dose oral contraceptives containing ethinylestradiol and gonane progestins.

In a prospective double-blind study of the effects of two low-dose oral contraceptives (OCs) on lipid and lipoprotein metabolism, two groups of eighteen young healthy women selected at random were submitted to a six months' use of either monophasic ethinylestradiol (EE) + desogestrel (DG) or triphasic EE + levonorgestrel (LNG). Total cholesterol (C), triglycerides (TG), phospholipids (PL), low density lipoprotein-cholesterol (LDL-C) and high density lipoprotein-cholesterol (HDL-C) together with apoproteins A-I, A-II, B and lecithin cholesterol acyltransferase activity (LCAT) were determined in serial plasma samples collected before, at three and six months during, and one month after OC use. Cholesterol and apoproteins (A-I, A-II, B) composition of lipoproteins (HDL-2, HDL-3, LDL) isolated by ultracentrifugation were additionally determined. On Mono-EE + DG, plasma TG (+39.3%, +45.6%), PL (+21.9%, +16.8%) and apo A-I (+35.5%, +23.3%) levels were significantly increased at 3 and 6 months of use; plasma HDL-C (+24%) and Apo A-II (+21.4%) were transiently increased at 3 months. Lipid and apoprotein composition of HDL-2, HDL-3 and LDL were unchanged. On Tri-EE + LNG, a slight but not significant decrease in HDL-C was observed throughout the study while other plasma lipids and apoproteins were unchanged. Ultracentrifugation revealed a lower content of C (-44.2%) and apo A-I (-44.6%) in HDL-2. LCAT activity expressed as molar esterification rate (MER) rose in a more sustained way during EE + DG use than during EE + LNG treatment. Covariance analysis shows a further significant difference between results of both treated groups for the Apo AI/Apo B ratio that was increased by Mono-EE + DG.

Adult↗