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Biomedical subjects

M Bourin

Publications and source records attributed to M Bourin.

At least 145 records · Page 8Linked to original sources
PubMed1986

Pharmacokinetics of isoniazid: influence of age.

The distribution of the acetylator phenotype of isoniazid was studied in 458 patients of different ages, and the influence of age on its apparent distribution volume, clearance and half-life was investigated in slow and rapid acetylators. The doses of isoniazid for the patients were determined according to the inactivation index method, as described by Vivien. Apparent distribution volume showed no difference between slow and rapid acetylators but it did decrease significantly with age. Clearance and half-life varied significantly in slow acetylators, and these variations led to a decrease in the necessary dose of isoniazid.

Acetylation↗
PubMed1986

Piracetam interactions with neuroleptics in psychopharmacological tests.

Two psychopharmacological tests which usually predict neuroleptic activity were conducted after joint administration of piracetam and three neuroleptics (haloperidol, fluphenazine and sulpiride) chosen for their different chemical classes and dopaminergic affinities. In these tests, specific doses of the neuroleptics were used to determine whether piracetam induced potentiation or antagonism of their action. Overall, piracetam increased neuroleptic action regardless of the administration timetable used, but the interaction of fluphenazine differed from that of the other two substances, because piracetam did not modify its action in a specific test of the presynaptic DA-2 dopaminergic receptors. This variation for fluphenazine may be explained by the fact that its pKa value is closer to that of piracetam, thus preventing better bioavailability of the neuroleptic, or its better affinity for DA-1 dopaminergic receptors. Nevertheless, the variation may have been due to a differing affinity for dopaminergic receptors, although this hypothesis is not completely satisfactory because it does not account for differences due to the administration timetable. It is thus suggested that action occurs on nonspecific sites and has the effect of increasing overall neuroleptic bioavailability.

Amphetamines↗
PubMed1986

Pharmacokinetic study of ioxaglate, a low osmolality contrast medium, in patients with renal failure.

Determination of changes in plasma concentration of ioxaglate in patients with renal failure made it possible to demonstrate that distribution and clearance of this contrast medium, as in the case of classic uroangiographic products, conform to an open two-compartment model with clearance from the central compartment. Various pharmacokinetic parameters were calculated. The metabolic clearance of ioxaglate was lower for all 6 patients studied, as compared with results for 3 normal subjects tested, but less marked than with iodamide, a contrast medium involving tubular secretion.

Adult↗
PubMed1985

Theophylline: a haemoperfusion modelisation.

A dynamic study of the kinetics of theophylline adsorption in aqueous medium by two adsorbent resins is proposed. The adsorption process involves Van der Walls pattern physical bonds. An in vitro haemoperfusion apparatus was schematized and data describing the adsorption-desorption process was obtained. A mathematical treatment led to the conclusion that first-order adsorption and desorption rates are involved, results which led to the consideration of a model of in vivo haemoperfusion in the case of first-order adsorption and desorption, with first-order corporeal elimination. The results indicate that one of the resins used, Amberlite XAD4, already known as a haemocompatible resin, is useful in eliminating theophylline.

Adsorption↗
PubMed1985

Theoretical study of haemoperfusion: drugs obeying a one-compartment pharmacokinetics model.

A general theory of haemoperfusion for drugs obeying the one-compartment pharmacokinetics model is proposed. The following theoretical cases are investigated: First case Adsorption and desorption are first-order reactions without biotransformation, and elimination rate is first-order. Two particular cases are examined: no desorption and alpha = beta. Second case: Adsorption and desorption rates are first-order, without biotransformation, and elimination rate is zero-order. Third case: Adsorption rate is first-order and desorption rate is zero-order, without biotransformation, and elimination is either first-order or zero-order. Fourth case Adsorption rate is zero-order and desorption rate is first-order, without biotransformation, and elimination is either first-order or zero-order. Fifth case: Adsorption and desorption rates are first-order, with biotransformation. In all these pharmacokinetics models for haemoperfusion, theoretical computations lead to the values of adsorbed amount and plasma level, in relation to time. Clearances are also computed. In most cases, haemoperfusion must be performed quickly because of the desorption phenomenon. Parameters modulating the adsorption process are: surface area, blood flow, drug concentration in blood, adsorbent nature and adsorbent quantity.

Adsorption↗
PubMed1984

A monitoring study of cardiotonic treatment by immunoenzymologic measurement of digoxinemia (emit).

We performed a study on 96 patients to compare monitoring by immunoenzymologic measurement (EMIT) of digoxinemia. In doing so, we uniquely relied on clinical and electrocardiographic results. Compliance was good because only 9 patients had a digoxinemia equal or below 0.8 ng/ml, but we emphasize that our patients were hospitalized. Correlation between intoxications and plasmatic levels shows that 5 patients presented clinical or electrocardiographic signs indicative of digitalis intoxication with a digoxinemia less than 2.5 ng/ml and 14 patients without intoxication with a digoxinemia higher than 2.5 ng/ml. We point out in this study that for EMIT immunoassay it is better to take 2.5 ng/ml as the concentration limit to be sure to avoid intoxication.

Adult↗
PubMed1983

[Resorption of drugs through the vaginal wall].

Drug absorption during vaginal administration. A method is described (systems approach to vaginal delivery of drugs and development of in situ vaginal drug absorption procedure) and is able to show vaginal absorption of drugs. Some drugs are rapidly and largely absorbed through vaginal epithelium: Metronidazole (Flagyl), Prostaglandins, Estrogens, Polyvidone-iodine (Betadine), Chloroquinadol (Gynotherax), d-Methadone, Hexachlorophene (Phisohex et Ultralan), Insulin and Triclosan. Other drugs are poorly absorbed: Amphotericin B (Fungizone, Amphocycline), Econazole (Pevaryl) and Trimethoprim. At least, some drugs are not absorbed: Nystatine (Mycostatine) and Furazolidone (Tricofuron).

Absorption↗
PubMed1983

The value of the reserpine test in psychopharmacology.

Numerous tests have been proposed to search for a possible antidepressive action. Many of these tests are based on a reversal of different reserpine effects, an approach justified mainly by the use of most the classic or new antidepressants. Three effects of reserpine were examined in mice: hypothermia, ptosis and akinesia. All tests were performed with reserpine 2.5 mg/kg, and the drugs were injected 4 h after reserpine administration. In these three models, we studied the relatively specific effects of 21 drugs known for their influence on the metabolism or action of norepinephrine (noradrenaline), serotonin and dopamine. Our results suggest that hypothermia antagonism is only obtained with drugs stimulating beta-adrenergic receptors directly or indirectly, ptosis antagonism with those stimulating alpha-adrenergic or serotonergic receptors, and akinesia antagonism with those stimulating dopaminergic receptors.

Animals↗
PubMed1982

[A study of three potential antidepressants (amineptin, mianserin and nomifensin) on the cardiovascular system and isolated intestine (author's transl)].

We studied the effects on the cardiovascular system and isolated intestine of three potential antidepressants : amineptin, nomifensin and mianserin. 1) No animals died in spite of doses well above the therapeutic range, evidencing the good tolerance of the compounds. 2) Effects on heart rate were variable; the only significant effect was cardioacceleration seen with mianserin in doses above 5 mg/kg. 3) The only significant effect on the auriculoventricular refractory period was recorded with mianserin. 4) Amineptin was the only compound that increased blood pressure. 5) Auriculoventricular conduction was slowed with mianserin in doses above 10 mg/kg. 6) On isolated rat duodenum, mianserin was spasmogenic in concentrations above 100 microgram/100 ml. 7) in comparison to tricyclic antidepressants, these three compounds carry only few risks of adverse side-effects.

Animals↗
PubMed1982

[Phenobarbital in the newborn (author's transl)].

Neonates with severe cerebral damage are usually given phenobarbital. The authors study the various means of administration and the influence of term and concomitant mannitol administration on the plasma levels of the drug. They recommend the intravenous administration of a load dose and show that phenobarbital blood levels are significantly less in prematures or in children who have been given mannitol.

Administration, Oral↗
PubMed1981

[The new versus the old antidepressant drugs: a comparative study of their psychopharmacological profiles (author's transl)].

We studied 13 known or potential antidepressants, choosen in different pharmacological classes: desipramine, imipramine, nialamide, dexamphetamine, AHR 1118, amineptine, iprindole, mianserine, nomifensine, salbutamol, TRH viloxazine, zimelidine. Each of these compounds was studied on 8 psychopharmacological tests: motor activity, reserpine induced hypothermia, reserpine induced ptosis, oxotremorine induced hypothermia, oxotremorine induced tremors, high doses apomorphine induced hypothermia, potentiation of toxic effects of yohimbine, behavioural despair. Clinical active compounds are efficient on yohimbine test and at least on one model of hypothermia; with a few exceptions, easy to explain, substances with a clearly demonstrated antidepressant activity in human have some common effects; these common effects can be used to predict, from animal experiments, an antidepressant effect in man.

Animals↗