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Biomedical subjects

M Bethenod

Publications and source records attributed to M Bethenod.

At least 55 records · Page 3Linked to original sources
PubMed1979

Metabolism of theophylline to caffeine in premature newborn infants.

Plasma concentrations of theophylline and caffeine in seven premature neonates receiving theophylline orally for treatment of apnea at age one to 9 days were measured by high performance liquid chromatography, ultraviolet spectrophotometry, and mass spectrometry. Plasma concentrations of caffeine increased from 1.8 mg/l (range = 0.1 to 3.7) at day one to 3.7 mg/l (1.3 to 8.0) seven days after initiation of theophylline therapy. Similarly, plasma concentrations of theophylline were 4.6 mg/l (1.5 to 7.5) and 11.0 mg/l (4.0 to 19.0) on days one and 7 of theophylline therapy, respectively. In contrast, four normal adult volunteers given theophylline orally for eight to ten days had plasma theophylline concentrations ranging from 3 to 14 mg/l but no measurable caffeine. This indicates that caffeine is a biotransformation product of theophylline in premature neonates and that the metabolic pathway followed by theophylline in premature infants includes a methylation reaction producing caffeine, whereas in adults, the major metabolic pathway involves oxidative reactions (demethylation and oxidation). Some pharmacologic effects attributed to theophylline during chronic therapy for apnea may in part be due to caffeine. Routine monitoring during theophylline therapy in premature neonates with apnea should include plasma concentrations of both theophylline and caffeine in order to assess the total methylxanthine load.

Adult↗
PubMed1979

[Survey on retrolental fibroplasia in France].

From 1964 to 1976, 20 cases of retrolental fibroplasia were recorded in the south of France while 38 cases were recorded in the north from 1970 to 1977. The more children are immature, the more they are liable to suffer from this disease. Etiological factors are apparently not limited to oxygen, which however plays the most important part in the process.

France↗
PubMed1979

[Present status of retrolental fibroplasia in France].

A national survey showed that retrolental fibroplasia still exists in France, as it does in other countries of the world. Retrolental fibroplasia is a condition that principally affects low birth weight premature babies in whom oxygen therapy has not been adequately controlled. The premature babies who have apnaeic attacks are most risk. Strict control of all oxygen therapy, preferably using continuous monitoring techniques together with other changes in the methods of treatment should reduce the incidence of this condition.

Apnea↗
PubMed1977

Congenital rickets. Study of the evolution of secondary hyperparathyroidism.

A case of congenital rickets of nutritional origin is described in a light-for-date premature infant (gestational age 34 weeks, birthweight 1 100 g). X-rays of the long bones showed spread, frayed and cupped metaphyses at birth and at the age of 16 days. Serum calcium was 8.2 mg/100 ml, phosphorus 3.4 mg/100 ml and alkaline phosphatase (A.P):323 IU/ml (N less than or equal to 200) at the age of 3 days. Very high level of serum immunoreactive parathroid hormone (iPTH) was found at the age of 16 days=295 micronlEq/ml (N less than or equal to 50). Evidence of maternal vitamin D deficiency was demostrated by low plasma 25-hydroxycholecalciferol (25-OH-CC):1.0 ng/ml (N:13.2+/-4.2) soon after delivery; it was found to be normal (10.2 ng/ml) six months later. Ca infusion (15 mg/kg/3 h) resulted in a marked fall of serum iPTH (280 to 84 micronlEq/ml). Administration of vitamin D2 (2400 IU/day for 10 days) induced some healing of the metaphyses; A. P. remained elevated (400 IU/ml); plasma 25-OH-CC was normal 10.2 ng/ml and serum iPTH was 115 micronlEq/ml. When 25-OH-CC was given orally for ten days (15 microng/day), plasma 25-OH-CC rose to 64.5 ng/ml with a minor change of serum iPTH (94 micronlEq/ml); X-rays of the bones showed osteoporosis. These results suggest a reduced convertion of 25-OH-CC into 1-25-(OH)2-CC.

Adult↗
PubMed1976

Unusual low plasma renin hypertension in a child.

A four-year-old girl with hypertension (140/60) and chronic hypokalemic alkalosis was studied to determine the origin of this clinical feature. High exchangeable sodium (56.7 meq/kg vs. 45-55 meq/kg in controls) was associated with a low plasma renin activity (6 ng/1/min vs. 26 +/- 3.1 in controls) and reduced aldosterone secretion rate (5.56 mug/day; normal: 50-150 mug per day)). A low corticosterone secretion rate (0.228 mg/day vs. 0.50-0.65 in controls) and urinary tetrahydrodeoxycorticosterone (0.007 mg/day vs. 0.03-0.09 mg/day in controls) were found. The basal secretion rate of cortisol was also low (1.80 mg/m2/day vs. 5.4-16.7 mg/m2/day in controls) in spite of normal plasma ACTH: 78 pg/ml. The normal increase of the cortisol secretion rate (from 1.80 to 65 mg/m2/day) after synthetic ACTH stimulation ruled out a 17 alpha hydroxylase deficiency. The low sweat Na/K ratio (0.25) and the good suppressing efficacy of dexamethasone and of the spironolactones on hypertension and on the hypokalemic alkalosis agreed with the hypersecretion of a mineralocorticoid. The secretion rate of 18 hydroxydeoxycorticosterone was high (91 mug/day/1.73 m2 vs. 40-80 mug per day and per 1.73 m2). As the mineralocorticoid potency of this steroid is weak, we speculate that it might be the precursor of a more potent but unknown mineralocorticoid which could influence the ACTH secretion.

18-Hydroxydesoxycorticosterone↗
PubMed1975

[2 cases of trisomy 11q(q23.2-- qter) with the same abnormality of external genitalia].

Two unrelated individuals are reported with the same clinical picture and trisomic for the same segment of chromosome 11 (q23 leads to qter). That both were seen because of micropenis raises the possibility that genes interfering with the reproductive function are located on chromosome 11 and that the q23 band might be a preferential breakage point of chromosome 11. Certain earlier reports support such a possibility.

Abnormalities, Multiple↗