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Biomedical subjects

M Dumont

Publications and source records attributed to M Dumont.

At least 253 records · Page 14Linked to original sources
PubMed1978

Lack of parallelism between microsomal enzyme induction and phenobarbital-induced hypercholeresis in the rat.

The relationship between microsomal enzyme induction and the increase in bile flow associated with phenobarbital administration was studied in rats in three experimental situations: examination of the time-course effect of a single dose of phenobarbital (8 mg/100 g body weight) on bile flow and hepatic cytochrome P-450 concentration; study of the influence of SKF 525-A (8 mg/100 g body weight) and cobaltous chloride (6 mg/100 g body weight/day for 3 days) on the phenobarbital-induced hypercholeresis. It was observed that: (a) the maximal increase in bile flow occurred 18 h after the single injection of phenobarbital, while the maximal increase in cytochrome P-450 occurred at 48 h; (b) in rats pretreated with phenobarbital for 3 days, SKF 525-A did not suppress the hypercholeresis due to phenobarbital, and (c) in rats treated with phenobarbital and cobaltous chloride, cytochrome P-450 concentration in the liver was not increased, while bile flow was increased to approximately the same extent as in animals treated with phenobarbital alone. These results further support the hypothesis that microsomal cytochrome P-450-dependent enzyme induction and increase in bile flow are two separate effects of phenobarbital.

Animals↗
PubMed1978

Maternal and fetal plasma renin and dopamine-beta-hydroxylase activities in toxemic pregnancy.

Toxemic and normotensive pregnant women were compared for plasma renin activity (PRA), aldosterone (PA), and dopamine-beta-hydroxylase (DBH). At term, hypertensive patients exhibited higher levels of PRA and PA, but similar levels of DBH, progesterone, and estradiol. Their elevated blood pressure was significantly correlated to their levels of PRA. During the delivery levels of PRA increased significantly in toxemic patients in spontaneous labor. Venous and arterial cord PRA levels were higher in babies born to hypertensive mothers than in babies born to normotensive mothers. Three days postpartum, maternal PRA level was lower than at term. Seven days postpartum, PRA levels remained higher in toxemic than in normal women. Maternal DBH levels did not change during and after delivery. Levels of DBH were undetectable in cord blood. We conclude that the renin-angiotensin system is involved in the pathogenesis of toxemia.

Adult↗
PubMed1978

[Copper intra-uterine devices (I.U.D.) and pregnancy: a study of the metabolism of copper and of ceruloplasmin in the mother and in the products of conception (author's transl)].

The authors studied the variations in levels of copper and ceruloplasmin in the mother and in products of conception during the first trimester of pregnancy, during the 4th month of pregnancy and near term, having a series of 12 pregnancies with the copper I.U.D. in position. No change was observed between the levels of copper and ceruloplasmin in comparison with a control series.

Abortion, Induced↗
PubMed1978

[Plasma prolactin, progestrone and oestradiol during labour and postpartum (author's transl)].

The changes in the levels of plasma prolactin, progesterone and oestradiol were studied in 20 women during labour and immediately after delivery. The study of these levels shows that there is a mechanism for inhibiting the galactopoietic action of prolactin. Lifting this inhibition allows the milk to come in. This inhibition is probably due to circulating steroids, but this study does not allow us to differentiate clearly between the respective roles of oestradiol and progesterone, chiefly because of their short half-life.

Estradiol↗
PubMed1978

[Myasthenia and pregnancy (author's transl)].

In the past 25 years, we have studied 73 cases of Myasthenia. 19 of these have had 24 pregnancies. We confirm the results that are given in the literature (15). Pregnancy does not trigger off Myasthenia. The action of pregnancy on Myasthenia is variable and there is an equal chance of worsening, improvement or a stationary state of the condition. All the same, patients who are well stabilised and have been for some time do not become worse. Worsening, when it does happen, happens especially in the first trimester of the pregnancy and calls for precise observation of the patient in order to regulate the treatment. Myasthenia has no direct or indirect action on the fetus and the pregnancy is not disturbed. Labour can be normal but the second stage often has to be aided because of the patient's muscle tiredness. In labour and particularly in the second stage an acute crisis can occur with difficulty in breathing. For this it is necessary to have an anaesthetist present who can resuscitate the patient and if necessary give respiratory aid by ventilation. Curare and like substances are absoultely contra-indicated if general anaesthesia is required. Transitory neonatal Myasthenia is rare, but the severity of the respiratory complications can be such that is should be sought for routinely and if there is the slightest doubt the newborn should be transferred to the special care neonatal unit.

Anesthesia, Obstetrical↗
PubMed1977

Barbiturate-induced choleresis: possible independence from microsomal enzyme induction.

The influence of four barbiturates, phenobarbital, barbital, thiopental, and pentobarbital, on bile secretion and on the hepatic microsomal system was studied in anesthetized rats. The barbiturates were injected intraperitoneally for 4 days and the animals were studied on the 5th day. It was found that: (1) phenobarbital, barbital, and thiopental, but not pentobarbital, significantly increased liver weight, cytochrome P-450 concentration in the liver, decreased pentobarbital sleeping time and induced a hypertrophy of the smooth endoplasmic reticulum in the hepatocytes at electron microscopy; (2) in contrast, the four barbiturates, including pentobarbital, significantly increased bile flow; this increase was attributed to an increase in the bile acid independent bile flow. There was no correlation between the increase in bile flow and the cytochrome P-450 concentration in the liver. It is concluded that the increase in bile flow observed after barbiturate treatment in the rat is possibly independent of the hepatic microsomal enzyme induction produced by these drugs.

Animals↗