PubMed Health⌕ Search

Biomedical subjects

J Homoki

Publications and source records attributed to J Homoki.

29 records · Page 2Linked to original sources
PubMed1975

Thyroid function in term newborn infants with congenital goiter.

Eighty-four term newborn infants without goiter and 45 newborn infants with congenital goiter were studied with regard to thyroid function. The radiologic development of the femoral and tibial epiphyses was evaluated in those with goiter. Fifty-eight percent of the patients had retarded bone age, markedly elevated TSH levels, elevated TBI, decreased total T4I, and decreased PBI values. Forty-two percent of newborn infants with congenital goiter had a normal bone age, normal values for TSH, PBI, and total T4I, and elevated values for TBI. It is concluded that the 58% of the newborn infants with congenital goiter had subtle hypothyroidism. They require substitution therapy with thyroid hormones in order to avoid possible retardation of normal brain development. Patients with congenital goiter who have no biochemical evidence of hypothyroidism should also be treated with thyroid hormones to achieve rapid regression of goiter.

Bone Development↗
PubMed1975

The concentrations of total cortisol and corticosterone in mixed cord plasma.

Cortisol and corticosterone were determined in mixed umbillical cord plasma of 43 healthy full-term newborns. The method consisted of a combined thin-layer chromatographic-fluorimetric procedure which proved to be specific and reliable. The mean concentration in cord plasma of cortisol was 10.6 plus or minus 4.9 mug/100 ml, of corticosterone 1.8 plus or minus 0.8 mug/100 ml. The mean ratio cortisol/corticosterone F/B was 6.3 plus or minus 2.5. Neither the duration nor the time of day of delivery appeared to influence the concentration of cortisol or corticosterone in umbilical cord plasma. Also, there was no significant difference between male and female infants. In 18 instances of a pathological course of gestation and/or delivery the mean cortisol level was 9.1 plus or minus /.7 mug/ml, the mean corticosterone level 2.2 plus or minus 9 mug/100ml. The mean F/B ratio was slightly but not significantly decreased (4.2 plus or minus 1.4 mug/100 mo; p larger than 0.05). It is speculated that the high corticosterone concentration in umbilical cord plasma reflects a defect in cortisol biosynthesis (17 chi-hydroxylase deficiency) in the newborn, compared with later life.

Circadian Rhythm↗
PubMed1975

Genetic differences in the cortisol concentration of the adrenal and other tissues of white and coloured guinea-pigs.

The effect of genetic difference (white v. coloured) on the cortisol content of ten different organs and tissues, including the adrenals, of white and coloured guinea-pigs of both sexes and of different ages was studied by protein-binding techniques. Tissue cortisol concentration was significantly higher in all the tissues and adrenals of white animals of both sexes compared with coloured animals. The difference in tissue cortisol content between white and coloured animals was higher before (range 41-5-134-1%) than after puberty (range 10-1--82-5%). The age-dependent decrease of cortisol concentration in different tissues and adrenals in adults was more marked in white guinea-pigs of both sexes (mean 30-6%, range 0-0--71-5%) than in coloured (mean 16-9%, range 0-0--63-1%. In adult animals the liver contained significantly (11-8--36-4%) more cortisol than in prepubertal animals. This pattern was the same in white and coloured guinea-pigs of both sexes.

Adrenal Glands↗
PubMedDate not supplied

A paradox: elevated 21-hydroxypregnenolone production in newborns with 21-hydroxylase deficiency.

21-Hydroxypregnenolone and its metabolite 5-pregnene-3 beta, 20 alpha 21-triol have been measured in the sulfate fraction of neonatal urine. These two steroids are the major two 21-hydroxylated 5-pregnenes produced by neonates and are almost exclusively excreted as disulfates. The excretions of these steroids by normal infants and infants with 21-hydroxylase deficiency were compared. In addition to measurement of the absolute excretion, the excretion relative to the total 3 beta-hydroxy-5-ene output was also determined. The results show that 21-hydroxypregnenolone excretion is highly elevated in 21-hydroxylase deficiency (affected, mean 887 micrograms/24 h, range 453-1431 micrograms/24 h; normal, mean 117 micrograms/24 h, range 17-263 micrograms/24 h), but when compared to excretion of other delta 5 steroids the excretion is slightly low [(21-hydroxypregnenolone + 5-pregnene-3 beta, 20 alpha, 21-triol)/total 3-beta-hydroxy-5-ene steroids, 2.9% affected; 3.6% normal]. This difference was not statistically significant. There is thus no evidence that the 21-hydroxylase acting on pregnenolone is deficient in congenital adrenal hyperplasia. The explanation of the normal activity of "pregnenolone 21-hydroxylase," although not clearly defined, is probably associated with two recent findings by other workers: (a) that the human fetus has an active 21-hydroxylase distinct from the adrenal enzyme and (b) that a 21-hydroxylase structurally very different from the adrenal enzyme, with high activity towards pregnenolone (but no activity towards 17-hydroxyprogesterone), has been isolated from rabbit hepatic microsomes.

17-alpha-Hydroxypregnenolone↗