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Biomedical subjects

D Knorr

Publications and source records attributed to D Knorr.

At least 55 records · Page 3Linked to original sources
PubMed1987

Evidence of 11 beta-hydroxylase deficiency in childhood adrenocortical tumors. The plasma corticosterone/11-deoxycorticosterone ratio as a possible marker for malignancy.

In search for a biochemical marker to differentiate between adrenocortical carcinoma (AC) and adenoma (AA), plasma levels of the following steroids were studied preoperatively and postoperatively: 11-deoxycorticosterone (DOC), corticosterone (B), 11-deoxycortisol (S), and cortisol (F). Levels were measured by Sephadex LH-20 chromatography and specific radioimmunoassays. The subjects included eight children ages 2 years, 5 months to 9 years, 10 months. There were three girls and 5 boys with pseudoprecocious puberty due to adrenocortical tumors (histologically, four were AC and four, AA). The preoperative showed that DOC and S levels were elevated in all patients, F levels were elevated in four of eight children when compared with age-matched controls, whereas B was normal. Postoperatively, all levels returned to normal. The ratios of B/DOC and F/S as an index of adrenal 11 beta-hydroxylase activity were calculated. The preoperative ratios of B/DOC were markedly decreased in all patients with AC compared to controls (7.7,4.1,5.9,1.9 versus 23.5, median), but normal in three of four patients with AA (16.2, 29.6, 16.1). The F/S ratios were significantly lower in AC and AA when compared with controls. The data indicate a deficiency in 11 beta-hydroxylation in cases of adrenocortical tumors. Despite a still limited number of patients, the decreased B/DOC ratios may possibly indicate malignancy and could be helpful in distinguishing by biochemical means between benign and malignant adrenocortical tumors.

Adenoma↗
PubMed1987

Dexamethasone-suppressible hyperaldosteronism: pathophysiology, clinical aspects, and new insights into the pathogenesis.

A profile of dexamethasone-suppressible hyperaldosteronism (DSH), a variant of primary aldosteronism, is drawn by reviewing its pathophysiological and clinical aspects. Genetic studies show no HLA linkage and point to an autosomal dominant mode of inheritance, suggesting that the prevalence of this disease has been underestimated in the past. Hypertension, hypokalemia, suppressed renin, and high aldosterone values characterize DSH in the basal state, similar to the other forms of primary aldosteronism, i.e., aldosterone-producing adenoma (APA) or bilateral idiopathic adrenal hyperplasia (IAH). Biochemically DSH and APA can be differentiated from IAH since in both aldosterone does not respond to upright posture, to angiotensin II infusion, and to angiotensin-converting enzyme (ACE) captopril. In contrast, morphologically DSH is similar to IAH, since neither macroscopic nor histologic examinations of the adrenals give evidence of any unilateral abnormality. However, DSH is differentiated from APA and IAH by the hyperresponsiveness of aldosterone to acute ACTH administration as well as by the failure of aldosterone to escape from prolonged ACTH stimulation. The final diagnosis of DSH rests upon the prompt reversal of the features of mineralocorticoid excess by glucocorticoid therapy. In some cases hypertension is unresponsive to dexamethasone and needs alternative treatment. The main pathogenetic hypotheses point to a pituitary and/or an adrenal abnormality, but the intrinsic nature of the disease remains to be elucidated.

Adenoma↗
PubMed1987

Androgen binding in cultured human fibroblasts from patients with idiopathic hypospadias.

Androgens stimulate development and growth of the external male genitalia. Since hypospadias represents the most common congenital abnormality in the male newborn and the mechanism of action in this disorder is still unclear, androgen binding was assessed in cultured fibroblasts from biopsies from genital skin of 10 patients with idiopathic hypospadias. For comparison, binding was determined in corresponding samples from 8 males with normal penile development and from 9 patients with known androgen resistance syndromes (testicular feminization, Reifenstein syndrome, pseudovaginal perineoscrotal hypospadias). Finally, binding was measured in 10 samples of nongenital skin. Maximum specific binding (Bmax) in idiopathic hypospadias varied from 3.2 to 15.5 (median 6.6) fmol.mg protein-1. Bmax in samples of persons with normal genital development was between 12.2 and 17.9 fmol.mg protein-1 (median 13.2). Bmax in samples of patients with known androgen resistance syndromes was exactly in the range reported previously in the literature. It is evident that Bmax in samples of patients with idiopathic hypospadias differs significantly (P less than 0.01), (Mann Whitney U-test) from those with normal genital development. Thus it seems reasonable to conclude that in some patients with idiopathic hypospadias the genital defect is caused by receptor deficiency.

Adolescent↗
PubMed1987

Plasma aldosterone and 11-deoxycortisol in term neonates: a reevaluation.

We reported previously reference values for seven corticosteroids in the plasma of term neonates and their mothers, including values for aldosterone (Aldo) that appeared high compared to the values in the literature. Plasma 11-deoxycortisol (S) was not measured in that longitudinal study. Using an improved technique of chromatographic separation of Aldo and S, the Aldo levels were measured again, and S levels were newly determined in stored plasma samples of the 12 newborn infants of our original report. The mean concentrations were: (Formula: see text). These plasma Aldo values should replace those of our original report. Thus, both plasma Aldo and S levels decline in the first week of life in normal infants.

17-Hydroxycorticosteroids↗
PubMed1987

Estrone and estradiol concentrations in human ovaries, testes, and adrenals during the first two years of life.

To determine the origin of estrogens in infant blood, we measured estrone (E1) and estradiol (E2) in the gonads of 50 girls and 64 boys who died suddenly between birth and 2 yr of age as well as in the adrenals of 18 of these infant girls and 16 of the boys. In the adrenals, E1 [median, 2.8 ng/g (10.4 pmol/g); range, 1.1-4.8 ng/g (4.1-17.8 pmol/g)] and E2 [median, 3.0 ng/g (10.9 pmol/g); range, 1.2-5.3 ng/g (4.4-19.5 pmol/g)] were found in similar concentrations and were independent of age and sex. In the gonads, E2 was the major estrogen, but the concentrations differed markedly between the sexes; E2 exceeded E1 almost 10-fold in the ovaries and 2-fold in the testes. On the average, the gonads of the infant girls had 5 times more E2 and 2 times more E1 than those of the boys. As in plasma, E2 concentrations were highest in the ovaries of 1- to 6-month-old girls [median, 10.5 ng/g (38.5 pmol/g); range, 1.1-55.1 ng/g (4.0-202.0 pmol/g)] and in testes of 1- to 3-month-old boys [median, 1.8 ng/g (6.6 pmol/g); range, 0.6-6.4 ng/g (2.3-23.5 pmol/g)]. Ovarian E2 concentrations declined to less than 3.0 ng/g (11.0 pmol/g) by the end of the first year of life, and testicular E2 declined to less than 1.0 ng/g (3.7 pmol/g) after only 6 months of age. Gonadal estrogen concentrations paralleled changes in gonadal morphology. Ovarian weights varied in a pattern of rise and fall similar to that of ovarian E2 concentrations; the biggest ovaries contained multiple macroscopic cysts. Testicular E2 closely correlated with Leydig cell development and testicular testosterone concentrations. We infer, therefore, that the surge of plasma E2 in infant girls originates from ovarian follicles and that of boys from testicular Leydig cells, and that these both occur as a result of the postnatal surge in gonadotropin secretion. The basal plasma E1 and E2 pool, however, is derived from the adrenals and remains at a comparatively constant level in both sexes.

Adrenal Glands↗
PubMed1987

The effects of cyproterone acetate on statural growth in children with precocious puberty.

Forty-four patients (42 f, 2 m) with precocious puberty (31 idiopathic, 1 familial, 7 cerebral, 5 McCune-Albright) were treated with cyproterone acetate for periods of 1-8.75 years in different (P less than 0.05) daily dosages of 117 +/- 6.1 mg/m2 per day (mean +/- SEM, group A, N = 20) and 60.8 +/- 2.42 mg/m2 per day (group B, N = 24). Thirty-three girls had experienced menarche before therapy at a mean age of 4.89 +/- 0.42 years. Treatment was started at a chronologic age of 5.45 +/- 0.33 years in the girls and 5.74 +/- 1.34 years in the boys. At the time of evaluation, 31 of our patients had reached final height. With respect to the effects of treatment on statural growth, the Standard Deviation Scores were retrospectively determined for height, weight, and growth velocity. The initial Bayley-Pinneau height predictions were compared with final height and target height, and the skeletal maturation was studied. There were no significant differences between those parameters in the patients of group A and B or between treated and untreated subjects as far as final height and target height were concerned. It is concluded that cyproterone acetate administered orally at daily doses from 50-150 mg/m2 does not improve statural growth of patients with precocious puberty.

Body Height↗
PubMed1987

Increased plasma cyclic guanosine monophosphate concentrations in children with high levels of circulating atrial natriuretic peptide.

Simultaneous measurements of plasma atrial natriuretic peptide (ANP) and cyclic guanosine monophosphate (GMP) concentrations were performed in children with various forms of cardiac diseases (n = 22) and in control children (n = 29). In healthy children, plasma ANP and cyclic GMP levels ranged between 2.4 and 98.0 (mean 45.8) pg/mL and 0.2 to 2.8 (mean 1.40) pmol/mL, respectively. In children with cardiac diseases, plasma ANP (26.0 to 499.7 [mean 188.7] pg/mL) and cyclic GMP (0.2 to 6.0 [mean 2.9] pmol/mL) levels were significantly higher than in control children (both P less than .0001). There was a linear correlation between the two values in children with cardiac diseases (P less than .01). Because the effects of ANP to target tissues are mediated by cyclic GMP, cyclic GMP appears to be a marker for the cellular responses to ANP. The increased cyclic GMP levels in children with cardiac diseases indicate that ANP exerts its effects on target organs also in states of chronically enhanced ANP levels.

Adolescent↗
PubMed1986

Contribution of the adrenal gland to the production of androstenedione and testosterone during the first two years of life.

Androstenedione and testosterone were measured in whole adrenal glands of 56 previously healthy boys who died suddenly between birth and 2 yr of age. In each adrenal gland, the concentration of androstenedione considerably exceeded that of testosterone. The highest concentrations were found during the first week of life (median, 295 ng/g; range, 98-320 ng/g). Thereafter, values decreased rapidly until the end of the first year of life (median, 10 ng/g; range, 4.4-22.7 ng/g). Adrenal testosterone concentrations averaged 15% of those of androstenedione in the same gland and similarly decreased until the end of the first year. The decrease of adrenal androgen concentrations paralleled the involution of the fetal adrenal zone. A close correlation existed between the concentration of androstenedione in adrenal tissue and plasma. However, no correlation existed between adrenal and plasma testosterone. When the adrenals and testes of the same infant were compared, there was 10 times more androstenedione in the adrenals than in the testes during the first 2 yr of life. The testes contained more testosterone than the adrenals only during the first 4 months. Thus, in infant boys the adrenals are the main source of androstenedione during the first 2 yr. After the sixth month of life, they also are the main source of testosterone.

Adrenal Glands↗
PubMed1986

Is heterozygosity for the steroid 21-hydroxylase deficiency responsible for hirsutism, premature pubarche, early puberty, and precocious puberty in children?

We applied the ACTH-stimulation test developed in our laboratory for the detection of heterozygous carriers of the 21-hydroxylase deficiency gene to patients suffering from hirsutism (n = 89), premature pubarche (n = 75), early puberty (n = 37), and precocious puberty (n = 22). While, in the general population, this test is positive in less than 2%, we found in 33% of hirsute patients, in 41% of patients with premature pubarche, and in 33% of patients with early puberty a hormonal response similar to the one seen in heterozygous carriers for the 21-hydroxylase defect. In contrast, only 18% of patients with precocious puberty responded abnormally. Thus we speculate that, at least in some patients with hirsutism, premature pubarche, and early puberty, heterozygosity for the 21-hydroxylase defect plays a major role in the pathogenesis of these disorders.

17-alpha-Hydroxyprogesterone↗
PubMed1986

[Congenital hypothyroidism--a diagnosis made by abdominal x-ray?].

Meteorism in a newborn may be a symptom of different diseases including hypothyroidism. It is caused by a disturbed peristalsis of the gut. Since in rare cases - as demonstrated in one infant - obligatory screening for hypothyroidism may be missed, meteorism should be considered a serious symptom and should lead to the right diagnosis before too much time is lost.

Congenital Hypothyroidism↗
PubMed1985

Ketoconazole blocks cortisol secretion in man by inhibition of adrenal 11 beta-hydroxylase.

We investigated basal and ACTH stimulated levels of cortisol, corticosterone, 17 alpha-hydroxyprogesterone, 11-deoxycortisol and 11-deoxycorticosterone as well as plasma levels of ACTH before and during the oral administration of ketoconazole in five patients with Cushing's syndrome (3 with bilateral adrenal hyperplasia, 1 with adrenal adenoma and 1 with adrenal carcinoma) and in three controls. The influence of ketoconazole on the transformation of 3H-17 alpha-hydroxyprogesterone to 3H-11-deoxycortisol and 3H-cortisol and of 3H-11-deoxycortisol to 3H-cortisol as well as of 3H-11-deoxycorticosterone to 3H-corticosterone was also examined in slices or homogenates of normal and hyperplastic adrenal tissue from four patients. Ketoconazole induced a rise of 11-deoxycortisol and 11-deoxycorticosterone, but not of cortisol and inconsistently of corticosterone which were increased by ACTH. Thus the ratio 11-deoxycortisol/cortisol rose more after ketoconazole than after ACTH and the ratio 11-deoxycorticosterone/corticosterone rose after ketoconazole but fell after ACTH. Plasma ACTH levels were stimulated 2-50 fold by ketoconazole. Incubation studies of adrenal tissue slices with 3H-17 alpha-hydroxyprogesterone showed that ketoconazole inhibited the transformation of 3H-17 alpha-hydroxyprogesterone to 3H-cortisol but not to 3H-11-deoxycortisol so that the ratio 3H-11-deoxycortisol/3H-cortisol increased 15-80 fold. After incubation of adrenal slices with 3H-11-deoxycortisol or 3H-11-deoxycorticosterone and ketoconazole, a 2-260 fold increase of the ratios 3H-11-deoxycortisol/3H-cortisol and 3H-11-deoxycorticosterone/3H-corticosterone were also found.

17-alpha-Hydroxyprogesterone↗
PubMed1985

Effect of a single bolus of etomidate upon eight major corticosteroid hormones and plasma ACTH.

In a prospective controlled trial we investigated the effect of an induction dose of etomidate (0.26 mg/kg i.v.) on plasma ACTH, progesterone, 17 alpha OH-progesterone, 11-deoxycortisol, cortisol, cortisone, corticosterone, 11-deoxycorticosterone, and aldosterone in seven males undergoing general anaesthesia. Seven other male patients receiving thiopentone at induction (5.0 mg/kg i.v.) served as controls. Plasma ACTH concentrations rose higher in the etomidate group (346 +/- 124 vs. 117 +/- 74 pg/ml, mean +/- SEM), but the difference was not significant. After etomidate we found a clear suppression of plasma cortisol (P less than 0.01), cortisone (P less than 0.01), corticosterone (P less than 0.01), and aldosterone (P less than 0.05) compared to corticosteroid levels after induction with thiopentone. Plasma 11-deoxycortisol and 11-deoxycorticosterone concentrations were grossly elevated 210 min after etomidate (91 +/- 28 nmol/l and 7.04 +/- 0.47 nmol/l, respectively, P less than 0.01) demonstrating inhibition of 11 beta-hydroxylation of both glucocorticoid and mineralocorticoid intermediates. In contrast, no significant difference in plasma progesterone and 17 alpha-OH-progesterone levels was found between the two groups indicating that the cholesterol-side-chain cleavage enzyme is less sensitive to etomidate than 11 beta-hydroxylase. Our results suggest that after induction of anaesthesia with a single bolus of etomidate, inhibition of other enzymes in the corticosteroid-synthetic pathway (e.g. cholesterol-side-chain cleavage enzyme) is of little clinical relevance.

17-alpha-Hydroxyprogesterone↗