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Biomedical subjects

U Kuhnle

Publications and source records attributed to U Kuhnle.

65 records · Page 4Linked to original sources
PubMed1984

Virilization without adrenal hyperplasia in 21-hydroxylase deficiency during fetal life.

The characteristic excess production of androgens in the cortisol 21-hydroxylase defect is generally considered to be secondary to ACTH stimulation of alternate pathways. Whenever a morphological examination of the adrenals has been possible in this disorder, adrenocortical hyperplasia was a constant finding. The availability of methods for the prenatal diagnosis of the 21-hydroxylase defect has made it possible to examine some of the manifestations of this disorder during fetal life. We studied a severely virilized 20-week-old aborted female fetus with the 21-hydroxylase defect whose adrenals were neither grossly enlarged nor microscopically hyperplastic. In a pregnancy at risk for congenital adrenal hyperplasia due to a 21-hydroxylase deficiency, amniocentesis was performed in the 18th week of gestation. The 21-hydroxylase defect was established by HLA typing and highly elevated levels of 17-hydroxyprogesterone, testosterone, and androstendione in amniotic fluid. After counselling, the parents, who already had a girl with the salt-wasting form of 21-hydroxylase deficiency, wished termination of the pregnancy. The aborted 20-week-old fetus was within the normal range for gestational age in weight and height. The external genitalia were ambiguous and extremely virilized, with an enlarged clitoris and fused labioscrotal folds. A urogenital sinus opened at the base of the clitoris. The internal organs were female, with a normal uterus and ovaries. Both adrenals were normal in size and weight for their gestational age. Histological examination of the adrenals revealed no abnormalities, and no hyperplasia was detectable. Thus, the adrenals in the 21-hydroxylase defect during fetal life secrete excessive amounts of androgens and cause virilization in the absence of adrenocortical hyperplasia.

Adrenal Hyperplasia, Congenital↗
PubMed1983

Diagnosis of homozygosity and heterozygosity in congenital adrenal hyperplasia (CAH) and control of treatment.

In congenital adrenal hyperplasia the incidence of 21-hydroxylase deficiency is very high (approximately 1:7,000), whereas other enzyme defects such as 11-hydroxylase deficiency, 17-hydroxylase deficiency and 3 beta-hydroxysteroid dehydrogenase deficiency are much less frequent. The various forms of enzyme defects can be diagnosed by determining specific plasma steroids or specific urinary steroid metabolites. A new semi-automatic capillary gas liquid chromatography method has been introduced for the diagnosis of CAH and assessment of therapy. Heterozygous carriers of 21-hydroxylase deficiency can be detected in the general population by measuring 17-hydroxyprogesterone plasma levels after ACTH stimulation; however, results overlap with the general population. In families with a CAH index case, heterozygosity and homozygosity for the 21-hydroxylase deficiency gene can be detected by HLA-typing. 21-hydroxylase deficiency can be diagnosed prenatally by HLA-typing or by determining 17 OH-progesterone levels in the amniotic fluid.

Adrenal Hyperplasia, Congenital↗
PubMed1983

Testosterone and androstenedione concentrations in human testis and epididymis during the first two years of life.

Testosterone and androstenedione were measured in testicular and epididymal tissue of 37 previously healthy infants between 1 and 24 months of age who died suddenly. In half of the patients elevated plasma levels of cortisol and androstenedione suggested preterminal stress. Plasma testosterone levels, however, did not differ from those in healthy infants. Testicular testosterone concentrations were maximal in boys from 1-3 months of age (median, 36.6 ng/g; range, 7-380 ng/g) with peak values similar to those found in pubertal or even adult testes. Thereafter testicular testosterone concentrations decreased and after the age of 6 months all values were below 12.5 ng/g, which corresponds to the low normal range of older prepubertal boys. Plasma testosterone and testicular testosterone correlated significantly (P less than 0.001). On average the testicular concentrations were 36.4 times higher than the corresponding plasma concentrations. Testicular androstenedione was low but correlated significantly with testicular testosterone (P less than 0.001). Epididymal testosterone concentrations were surprisingly high (1-3 months: median, 10.3 ng/g; range, 4-42.7 ng/g) and averaged 30% of the testicular testosterone concentration. Thus, epididymal testosterone concentrations were significantly higher than the circulating plasma testosterone levels, indicating the capacity of the infant epididymis to accumulate androgens. These findings suggest that high local testosterone concentrations during early infancy are important not only for the testis itself but particularly for the developing epididymis.

Aging↗
PubMed1983

The effects of long-term normalization of sodium balance on linear growth in disorders with aldosterone deficiency.

The effect of normalization of sodium balance was evaluated in children with aldosterone deficiency of several etiologies. In salt-losing congenital adrenal hyperplasia (CAH), treatment with a mineralocorticoid in doses that normalized plasma renin activity (PRA) induced a marked increase in linear growth. Serum 17-hydroxyprogesterone (17-OHP) and androgens fell further when adequate sodium balance was achieved, allowing in some cases a reduction in glucocorticoid replacement dose. Together with PRA measurement they were the most sensitive indicators of adequate mineralocorticoid and glucocorticoid replacement therapy. In 2 teenage children with aldosterone deficiency due to Addison's and autoimmune polyglandular disease similar improvement in growth as well as onset of puberty occurred when sodium balance was normalized by increased mineralocorticoid therapy. These studies show that adequate sodium balance is essential for normal growth and pubertal development.

17-alpha-Hydroxyprogesterone↗
PubMed1982

Development of negative feedback control of the hypothalamo-pituitary-gonadal axis in the male rat fetus.

Pregnant rats were passively immunized against testosterone by injections of rabbit antibodies against testosterone. Fetuses were studied daily starting at day 18 of gestation. Testosterone antibodies were detected in all fetal plasma samples. At day 18 of gestation testicular testosterone content - as an index of gonadotropin stimulation - was unchanged even though circulating free testosterone was reduced by antibody binding. However, at day 19 and all subsequent days of gestation testicular testosterone content was significantly higher in immunized fetuses compared to the controls. These results indicate that in the male rat the negative feedback between testes and the hypothalamopituitary system develops between days 18 and 19 of gestation.

Animals↗
PubMed1982

Urinary free and conjugated oestrone and oestradiol-17 beta in early infancy.

Conjugated and free urinary oestrone and oestradiol-17 beta were determined by radioimmunoassay in 98 urine samples of 44 normal male and female infants ranging from 7 days to 2 years of age. Both sexes excreted significantly more oestrone and oestradiol-17 beta during the first 3 months of life compared to the end of the first year. Values peaked at the beginning of the second month. During the first 7 months of life, female infants excreted significantly more conjugated oestradiol-17 beta than oestrone, whereas male infants consistently excreted equal amounts of conjugated oestradiol-17 beta and oestrone. However, both sexes excreted significantly more free unconjugated oestrone than oestradiol-17 beta during the same period.

Age Factors↗
PubMed1981

The 21-hydroxylase activity in the glomerulosa and fasciculata of the adrenal cortex in congenital adrenal hyperplasia.

In the two clinical syndromes of congenital adrenal hyperplasia due to a 21-hydroxylation defect of adrenal steroidogenesis, the simple virilizing and the salt-wasting forms, the 21-hydroxylase activity was studied considering the zona fasciculata and the zona glomerulosa of the adrenal cortex as two separate glands under different regulation. To test this hypothesis, we stimulated adrenal steroidogenesis by ACTH infusion or dietary sodium restriction in eight patients with congenital adrenal hyperplasia (four patients with the simple virilizing form and four with the salt-wasting form of congenital adrenal hyperplasia) and in six normal children. Both the 17-hydroxy and 17-deoxy pathways of adrenocortical steroid biosynthesis were examined by measuring serum concentrations of 17-hydroxyprogesterone, cortisol, progesterone, deoxycorticosterone, corticosterone, and aldosterone and the excretion of free deoxycorticosterone, 18-hydroxydeoxycorticosterone, corticosterone, 18-hydroxycorticosterone, cortisol, and aldosterone. We considered the steroids 18-hydroxycorticosterone and aldosterone to be primarily of zona glomerulosa origin. These studies indicated that the zona fasciculata of both the salt-wasting and the simple virilizing forms is defective in 21-hydroxylation of 17-hydroxy and 17-deoxy steroids. The zona glomerulosa demonstrated deficient 21-hydroxylation only in the salt-wasting form, whereas in the simple virilizing form, the glomerulosa was spared this defect.

Adrenal Cortex↗
PubMedDate not supplied

Diagnosis and monitoring of therapy of the various enzymatic defects causing congenital adrenal hyperplasia by semiautomatic capillary gas-liquid chromatography.

A semiautomatic capillary gas-liquid chromatographic method for the determination of urinary steroids has been developed. Trimethylsilylenol ethers were used as steroid derivatives instead of the more common methoxime trimethylsilyl ethers. The diagnosis of the various enzymatic defects causing congenital adrenal hyperplasia can be made using the characteristic pattern of urinary steroid chromatograms. Furthermore, the method presented can be used routinely to monitor therapeutic control in congenital adrenal hyperplasia. Reference data for patients of different age groups under good therapeutic control are presented.

3-Hydroxysteroid Dehydrogenases↗
PubMedDate not supplied

A partial form of pseudohypoaldosteronism type I without renal sodium wasting.

Multiple target organ involvement in pseudohypoaldosteronism is known but partial defects involving only a single organ system have also been described. In this report we present a girl with early symptoms and a very mild course of the disease without renal salt wasting and with normal sweat osmolality. Sodium content and the sodium/potassium ratio of stool was highly elevated. Increased plasma renin activity and aldosterone concentration as well as a reduced number of aldosterone receptors in mononuclear leucocytes confirmed the diagnosis of pseudohypoaldosteronism. Partial pseudohypoaldosteronism maybe more frequent than currently diagnosed since salt loss can be compensated by intact organ systems, but nevertheless threatens the young patient during illness. Since various degrees of clinical severity of pseudohypoaldosteronism even in the same family have been described, it seems important to identify mild cases in order to monitor younger siblings.

Female↗
PubMedDate not supplied

True hermaphroditism in an XY individual due to a familial point mutation of the SRY gene.

A number of genes are known to control the development of the testis but the transcription factor SRY encoded on the Y-chromosome is considered to play the major role in initiating the first step in determining testicular differentiation. Mutations in this gene usually result in gonadal dysgenesis, but it is interesting to note that at least three of these mutations have been found to be familial. Furthermore, fewer than 10% of true hermaphrodites carry an XY karyotype, and so far only two patients have been documented to carry a mutation in the SRY gene. We have identified a familial mutation in the SRY gene involving a previously described locus. The index patient was born with severely ambiguous genitalia and on histological examination the gonads revealed true hermaphroditism, containing ovarian as well as testicular tissue. The father, his three brothers, and his first-born son carry the identical mutation. The severely feminized XY individual was diagnosed shortly after birth, gonadectomized and raised as female. SRY was determined by PCR and subsequently sequenced using cycle sequencing. A previously published point mutation was identified at nucleotide position 680 resulting in a non-conservative exchange of the amino acid iso-leucine at position 90 into methionine. This position represents a mutational 'hot spot', which seems to retain a certain amount of protein activity, enabling normal male development in some individuals. The patient is the third one reported in whom a mutation in the SRY gene results in ovarian-like development. Since ovarian development in XY individuals is extremely rare, its mechanism is of great interest. Further studies in this family might allow the identification of factors initiating and stimulating ovarian development. How far these infantile ovaries would have developed normally, however, is merely speculative.

Chromosomes, Human, X↗