Biomedical subjects

J L Winnacker

Publications and source records attributed to J L Winnacker.

11 recordsLinked to original sources

PubMed1977

Rickets in children receiving anticonvulsant drugs. Biochemical and hormonal markers.

Forty-one epileptic children, aged 2 to 16 years, receiving combinations of phenobarbital, phenytoin, and primidone, and 39 control children were studied. The epileptics demonstrated slight but significant reductions in serum calcium, phosphorus, and 25-hydroxyvitamin D concentrations, and a significant increase in serum alkaline phosphatase values. No significant difference in serum immunoreactive parathyroid hormone levels was noted. Further analysis of the data revealed that patients whose drug therapy included primidone had the lowest serum levels of calcium and 25-hydroxyvitamin D. They had also received the largest number of drugs for the longest duration, and had serum phenobarbital levels that were significantly higher than those of other patients. The minimal degree of vitamin D deficiency in our epileptic children contrasts with the results of other investigations and warrants emphasis. The reasons for this difference are not apparent.

Adolescent↗

PubMed1976

Impaired release of parathyroid hormone in magnesium deficiency.

Parathyroid hormone release and end-organ responsiveness to parathyroid extract (PTE) were evaluated in a 25-year-old woman with magnesium deficiency associated with hypocalcemia and inappropriately low levels of serum immunoreactive parathyroid hormone (iPTH). End-organ responsiveness to PTE was demonstrated by increases in serum calcium and in urinary phosphorus, cyclic AMP, and hydroxyproline. When the serum calcium was increased from a baseline of 6.9 mg/100 ml to levels of 8.0 mg/100 ml and higher by calcium infusion, the serum iPTH decreased from the low normal range to below the limits of detectability. The intravenous administration of 3 mg/kg of body weight of magnesium led to an abrupt and striking increase in circulating iPTH with a 2-fold increase in one minute, a 6-fold increase in two minutes, and an 8-fold increase in five minutes. The very rapid increase in serum iPTH produced by magnesium infusion in this study suggests an effect of magnesium on hormone secretion rather than an effect on hormone synthesis. The evidence provided by this investigation indicates that the release of parathyroid hormone is impaired in magnesium deficiency and that the level of circulating calcium required for the suppression of parathyroid hormone secretion is lower than that in normal subjects.

Adult↗

PubMed1971