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Biomedical subjects

C Philibert

Publications and source records attributed to C Philibert.

6 recordsLinked to original sources
PubMed1999

The roles of P-glycoprotein and intracellular metabolism in the intestinal absorption of methadone: in vitro studies using the rat everted intestinal sac.

Methadone is used as a treatment for opiate detoxification in methadone maintenance programs. Intra- and inter-patient variations in methadone bioavailability have been observed after oral methadone treatment and this makes it difficult to predict a dosing regimen. Intestinal absorption and metabolism could explain these variations. The in vitro gut sac model was used to study the intestinal absorption of methadone, and it confirmed that methadone is a substrate for P-glycoprotein. The transport of methadone was increased in presence of P-gp inhibitors verapamil and quinidine. The appearance of a major metabolite of methadone, 2-ethylidene-1, 5-dimethyl-3, 3-diphenyl pyrrolidine (EDDP) in the gut sac contents also demonstrated the existence of intestinal metabolism of methadone.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1991

Effect of hydrogen fluoride inhalation on lipid metabolism in guinea pigs.

The action of fluoride in vivo (exposure 96 hrs to 7 mg/m3) on the metabolism of cyclic AMP and relationship between cAMP and lipid metabolism was investigated. The mean values for cAMP, non esterified fatty acids and cholesterol were significantly increased after hydrogen fluoride exposure. cAMP is directly responsible for the increased lipolysis. In animals exposed to HF, theophylline injection causes increases of non esterified fatty acids and not produces modification of cholesterol level.

Administration, Inhalation↗
PubMed1982

[Efficacy of PGF2 alpha on milk ejection during the sexual cycle of the cow].

After 30 days of lactation, 15 non-pregnant French Friesian cows were divided into groups A and B, balanced by the milk yield and lactation number of the cows. The 7 cows of group A were given a series of intrajugular prostaglandin F2 alpha (Upjohn Dinolytic) injections every morning, administered in increasing logarithmic doses (1, 4, 16, 64, 256, 1 024 micrograms). The aim of the experiment was to determine the minimal dose that would induce an increase in intramammary pressure (IMP) during the sexual cycle and milk let-down through a cannula in the teat cup. The 8 cows of group B were given a single injection of 256 micrograms of PGF2 alpha every morning to determine the changes during the sexual cycle in the response parameters of IMP (latency and amplitude) or of milk let-down (latency and collected volume) through a cannula. The following results were obtained: 1. The minimal dose of prostaglandin inducing milk let-down varied during the cycle; it was lower (1 to 16 micrograms) during the luteal phase (D4 to D12) than during the perioestral phase (256 to greater than 1 024 micrograms from D - 2 to D + 3) (figs. 2, 3). 2. During daily administration of the same dose (256 micrograms) of PGF2 alpha no response was obtained during the perioestral phase, while during the luteal phase; - maximal IMP deflection reached 12 to 14 mmHg (figs. 5, 6); - the volume of milk ejected was on an average higher than 3 liters per quarter (figs. 5, 6); - the latency time between injection and let down response was about 1.8 times shorter between D10 and D12 than between D4 and D5 (fig. 7). 3. The cyclic changes in the milk ejection parameters caused by PGF2 alpha were closely related to the plasma progesterone level (figs. 2, 3, 5, 6). The coefficients of correlation between the progesterone level and the - threshold dose: r = - 0.809** (group A), - volume of ejected milk: r = + 0.872*** (group B), - deflection amplitude: r = + 0.805*** (group B) were always significantly higher than the threshold of 0.001. Various hypotheses concerning the endocrine control of cyclic variations in milk let-down under the effect of PGF2 alpha are discussed.

Animals↗