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Biomedical subjects

M Zachmann

Publications and source records attributed to M Zachmann.

At least 37 records · Page 2Linked to original sources
PubMed1995

Defects in steroidogenic enzymes. Discrepancies between clinical steroid research and molecular biology results.

Molecular biology has clarified the understanding of steroidogenic enzyme genetics. Nevertheless, there are discrepancies between fundamental and clinical experience. (1) Why do patients with "pure" 17 alpha-hydroxylase or 17,20-desmolase deficiency exist, when one cytochrome regulates both steps? A case of interest is discussed, who had "pure" 17,20-desmolase deficiency until adolescence, but additional 17 alpha-hydroxylase deficiency thereafter. (2) In 11 beta-hydroxylase deficiency, it was puzzling to find 18-hydroxylated compounds, and, in isolated hypoaldosteronism, normal cortisol, since 11 beta- and 18-hydroxylation were thought to be regulated together. This has now been explained by differences in the fasciculata and glomerulosa. The occurrence of 11 beta-hydroxylase deficiency of 17-hydroxylated steroids only, however, remains enigmatic. (3) 3 beta-Hydroxysteroid dehydrogenase deficiency does not only seem to exist in classic (mutations of type II gene), but also in late-onset cases. In them, no molecular basis could be found. (4) Also, in cholesterol side-chain cleavage, there is an inequity: while evidently one cytochrome regulates 20- and 22-hydroxylation, pregnenolone is formed when 20 alpha OH-cholesterol, but not when cholesterol, is added to adrenal tissue of deficient patients. Other factors (promoters, fusion proteins, adrenodoxin, cAMP-dependent expression of genes, and/or proteases), or hormonal replacement in patients may be responsible for these discrepancies.

Adrenal Hyperplasia, Congenital↗
PubMed1995

Kallmann syndrome in a boy with a t(1;10) translocation detected by reverse chromosome painting.

Prometaphase chromosomes from a 16 year old boy with hypogonadotrophic hypogonadism and anosmia (Kallmann syndrome) showed a tiny chromosome fragment attached to the long arm of one chromosome 1 without a visible reciprocal translocation chromosome. Chromosome painting with libraries from chromosomes 1 and X excluded a t(X;1) translocation, but failed to detect a second translocation chromosome. Through reverse chromosome painting, an unbalanced der(1), t(1;10) (q44;q26) translocation could be detected. This is the third case of Kallmann syndrome with a de novo rearrangement between two autosomes. The distal long arm of chromosome 1 may contain a candidate locus for a gene, mutations of which may cause the Kallmann phenotype; a 10q location seems less likely.

Adolescent↗
PubMed1995

Replacement of growth hormone (GH) in normally growing GH-deficient patients operated for craniopharyngioma.

Removal of a craniopharyngioma usually results in panhypopituitarism. Some children, however, grow normally or even excessively after extirpation of the tumor despite a proven lack of GH and have so far not been treated with hGH. We studied the effects of short (2-day) and long term (1-yr) administration of hGH on metabolism and growth in six patients receiving regular hormonal replacement therapy. During short term human (h) GH treatment, 15N retention was not significantly increased (mean +/- SEM, 115.4 +/- 9.6% of basal balance) and was not different from the control value. In contrast, 15N retention was 210.3 +/- 20.7% in children with GH deficiency from other causes. Long term administration of hGH (2 IU/m2.day, sc, for 12 months) did not influence growth velocity, but increased the calf circumference and decreased the body mass index and skinfold thickness in prepubertal patients. Insulin-like growth factor-I (IGF-I), IGF-binding protein-3 (IGFBP-3), and the 150-kilodalton IGFBP complex were decreased before and restored to normal during treatment. The reverse was observed for the 50-kilodalton IGFBP complex. Growth (velocity) in these patients did not correlate with any of the usual indicators of the growth status and remains unexplained. Although hGH did not affect growth, it had other beneficial effects and is recommended for these patients.

Adolescent↗
PubMed1994

[Therapy with growth hormone in pediatric patients with chronic kidney insufficiency].

Statural growth in children with chronic renal failure (CRF) is often delayed. Several studies have shown that one of the main causes is partial resistance to growth hormone (GH), which can be overcome by supraphysiologic doses of recombinant human (rh) GH. Since August 1990 we have been treating 8 boys and 1 girl (ages 1.7-12.7, mean 5.3 yrs) with rhGH (4 IU/m2 s.c. daily). All patients were prepubertal and were 2.4-4.5 (mean 3.2) SDS below the mean normal height for age and sex. 5 patients were on dialysis. Mean growth velocity was -2.0 SDS (5.4 cm/yr) before and +2.6 SDS (9.5 cm/yr) during the first year of therapy with rhGH. Mean height increased from -3.2 to -2.5 SDS at 1 year. Height in the 4 boys treated > 2 yrs with rhGH improved from -3.3 SDS (before rhGH) to -2.4 (1st yr) and to -2.0 SDS (2nd yr); their height increased by 9.6 cm (1st yr) and 7.8 cm (2nd yr) as compared to 4.6 cm in the year before treatment. The response to rhGH was better in the 4 patients treated conservatively than in those on dialysis. Side effects did not occur. Plasma insulin increased but the oral glucose tolerance test remained normal. We conclude that treatment with rhGH represents an important step forward in selected pediatric patients with CRF. The excellent acceptance reflects the high expectations of the patients and their families.

Child↗
PubMed1994

Altered adrenal and thyroid function in children with insulin-dependent diabetes mellitus.

In 129 children, aged 12.6 +/- 3.8 years, affected by type 1 diabetes mellitus, the levels of dehydroepiandrosterone sulfate (DHEAS), cortisol, T3, fT3, T4, fT4, rT3, TSH, cholesterol, and triglycerides were evaluated and compared with those of a control group of 458 healthy age-matched children. The results were also correlated with hemoglobin HbA1C. The DHEAS-standard deviation score (DHEAS-SDS; -0.36 +/- 0.77) was significantly different from zero in diabetic children, while the cortisol serum level was higher than in control subjects (485 +/- 94 vs 359 +/- 132 nmol/l). Moreover, the DHEAS-SDS and DHEAS-SDS/cortisol ratio correlated negatively with HbA1c. Diabetic patients also showed lower T3 values (2.22 +/- 0.4 vs 2.32 +/- 0.3 nmol/l) and a higher rT3/T3 ratio (0.17 +/- 0.09 vs 0.15 +/- 0.05) than controls. There was a negative correlation between T3 and HbA1C. Cholesterol (4.77 +/- 1.08 vs 4.51 +/- 0.76 mmol/l) and triglycerides (0.82 +/- 0.53 vs 0.63 +/- 0.37 g/L) levels were higher in diabetic children and positively correlated with HbA1c, but not with DHEAS-SDS. We can therefore conclude that diabetes, particularly if poorly controlled, tends to induce a dissociation of cortisol and DHEAS secretion and a low T3 syndrome, similar to that seen in other illnesses.

Adolescent↗
PubMed1994

Virilizing adrenal tumour mimicking congenital adrenal hyperplasia with P450c11 (11 beta-hydroxylase) deficiency.

In a girl aged 5 years with a virilizing adrenal adenoma the urinary and plasma steroid findings suggested the diagnosis of congenital adrenal hyperplasia due to P450c11 (11 beta-hydroxylase) deficiency. After removal of the tumour clinical signs receded and the hormonal values normalized. RNA analysis of the tumour tissue revealed low amounts of P450c11 mRNA which indicates that P450c11 deficiency of the adenoma caused the steroid abnormalities in this girl.

Adenoma↗
PubMed1993

[Hypogonadism and delayed puberty. Indications for androgen treatment in adolescents].

Testosterone and synthetic androgens were once used somewhat uncritically; on account of the undesired side effects that are now known to occur, however, they should be employed very selectively, in particular in the young patient. Although the main indication is primary hypogonadism, they are also employed in the treatment of gonadotropin deficiency and constitutionally delayed growth and development. While, for the treatment of congenital anorchism a therapeutic scheme could be developed which closely approximated the physiological conditions, no generally applicable treatment schemes could be established for other forms of primary hypogonadism. In the case of constitutional retardation of growth and development, treatment is not indicated, for somatic reasons, although severe psychosomatic disturbances may make treatment necessary in many cases.

Adolescent↗
PubMed1993

Pituitary stalk thickening with diabetes insipidus preceding typical manifestations of Langerhans cell histiocytosis in children.

In up to 25% of cases of children with central diabetes insipidus no organic cause can be documented. We present three boys (age 2.2, 2.3 and 6 years at diagnosis) with acute onset central diabetes insipidus, in whom the only pathological finding using MRI was a thickened central part of the pituitary stalk (> 2.5 mm). Recent reports demonstrate similar MRI findings in adults with Langerhans cell histiocytosis (LCH), sarcoidosis, or tuberculosis, and in children with proven LCH and diabetes insipidus. In those adults with LCH, the pituitary stalk lesion has been histologically verified as a sequela of LCH. In contrast, in two of our three patients pituitary stalk thickening preceded the typical peripheral lesions of LCH by several months, whereas in the third patient there is as yet no evidence of systemic disease. We conclude that thickening of the central part of the pituitary stalk might represent the first manifestations of LCH clinically presenting with diabetes insipidus. MRI investigation of the pituitary stalk in children with unexplained central diabetes insipidus and accurate follow up in patients with thickening of the pituitary stalk in necessary to avoid missing other manifestations of a systemic disease.

Acute Disease↗
PubMed1993

Endocrine findings in male pseudohermaphroditism.

Recent discoveries in molecular biology have much clarified the regulation and function of steroid converting enzymes. Most progress has been made in the area of cytochromes, which regulate the side chain cleavage of cholesterol (P-450 SCC) and the 17 alpha-hydroxylase- and 17,20-desmolase (or 17,20-lyase) activities (P-450 17 alpha), as well as in 3 beta-hydroxysteroid dehydrogenase. Nevertheless, there are some discrepancies between fundamental knowledge and clinical experience, which are difficult to understand: why is it possible, e.g., that cases with "pure" 17 alpha-hydroxylase or 17,20-desmolase deficiency exist, when there is only one cytochrome regulating both steps? After a brief review of clinical and biochemical findings in the various defects of testosterone biosynthesis, a case is discussed which is of interest in this respect.

3-Hydroxysteroid Dehydrogenases↗
PubMed1993

Deficiency of 17-ketoreductase presenting before puberty.

The diagnosis of 17-ketoreductase deficiency is established in most patients at or after puberty when basal plasma androstenedione levels are high; data on prepubertal children are limited. Two infants with external female genitalia presented in infancy with inguinal herniae and palpable gonads. Both had a 46,XY karyotype, a short vagina, absent uterus, and a gonadal biopsy showing testicular tissue. The value of an hCG stimulation test in making the diagnosis of 17-ketoreductase deficiency was confirmed by a minimal plasma testosterone but marked androstenedione response. Androgen receptor deficiency based on studies in genital skin fibroblasts was demonstrated in one of the cases. We speculate that this is possibly the result of failed induction of receptors secondary to androgen deficiency. Though 'tomboyish' in behaviour, both children are reared as girls.

17-Hydroxysteroid Dehydrogenases↗
PubMed1992

Molecular basis of apparent isolated 17,20-lyase deficiency: compound heterozygous mutations in the C-terminal region (Arg(496)----Cys, Gln(461)----Stop) actually cause combined 17 alpha-hydroxylase/17,20-lyase deficiency.

The molecular defect in a reported case of isolated 17,20-lyase deficiency in a 46XY individual has been elucidated. The patient was found to be a compound heterozygote, carrying two different mutant alleles in the CYP17 gene. One allele contains a point mutation of arginine (CGC) to cysteine (TGC) at amino acid 496 in exon 8. The second allele contains a stop codon (TAG) in place of glutamine (CAG) at position 461 in exon 8 which is located 19 amino acids to the carboxy-terminal side of the P-450(17) alpha heme binding cysteine. COS-1 cells transfected with cDNAs containing one or the other of these mutations showed dramatically reduced 17 alpha-hydroxylase and 17,20-lyase activities relative to cells transfected with the wild type P-450(17) alpha cDNA. While the in vitro data in COS 1 cells can explain the patient's physical phenotype, with female external genitalia, it was somewhat discordant with the clinical expression of isolated 17,20-lyase deficiency with relative preservation of 17 alpha-hydroxylase activity in vivo. In addition to the expression studies of these two examples of mutants in the C-terminal region of cytochrome P-450(17) alpha, a third mutant cDNA construct containing a 4-base duplication at codon 480 previously found in patients with combined 17 alpha-hydroxylase/17,20-lyase deficiency was also expressed in COS-1 cells. This expressed protein was completely inactive with respect to both activities, supporting the biochemical findings in serum and in vitro biochemical data obtained using a testis from the patient. The results from these patients clearly indicate the importance of the C-terminal region of human P-450(17) alpha in its enzymatic activities.

Adolescent↗
PubMed1992

Progressive high frequency hearing loss: an additional feature in the syndrome of congenital adrenal hypoplasia and gonadotrophin deficiency.

In an earlier report, we found that X-linked congenital adrenal hypoplasia may be associated with gonadotrophin deficiency. This combination has since been confirmed by many others. At the last examination, our patients were 22.4, 19.9 and 17.5 years old. They were doing well on replacement therapy with hydrocortisone, fluorohydrocortisone, and long-acting testosterone, but in all of them, a progressive hearing loss had appeared, starting at high frequencies at about 14 years of age. The loss progressed with age to lower frequencies, and the oldest patient had some remaining hearing capacity at 125-500 Hz only with a perceptive hearing loss of -95 dB at frequencies above 500 Hz. It is concluded that patients with this syndrome should be examined for hearing loss. X-linked adrenal hypoplasia may also be associated with glycerol kinase deficiency and myopathy. A molecular XP-deletion has suggested a locus for hypogonadotrophic hypogonadism distal to the glycerol kinase and adrenal hypoplasia loci. The observations in our patients suggest that the locus for at least this type of X-linked deafness may be in the same area.

Adolescent↗
PubMed1992

Congenital adrenal hyperplasia due to point mutations in the type II 3 beta-hydroxysteroid dehydrogenase gene.

Classical 3 beta-hydroxysteroid dehydrogenase/delta 5-delta 4-isomerase (3 beta-HSD) deficiency is an autosomal recessive form of congenital adrenal hyperplasia characterized by a severe impairment of steroid biosynthesis in both the adrenals and the gonads. We describe the nucleotide sequence of the two highly homologous genes encoding 3 beta-HSD isoenzymes in three classic 3 beta-HSD deficient patients belonging to two apparently unrelated pedigrees. No mutation was detected in the type I 3 beta-HSD gene, which is mainly expressed in the placenta and peripheral tissues. Both nonsense and frameshift mutations, however, were found in the type II 3 beta-HSD gene, which is the predominant 3 beta-HSD gene expressed in the adrenals and gonads, thus providing the first elucidation of the molecular basis of this disorder.

3-Hydroxysteroid Dehydrogenases↗
PubMed1992

Familial adrenal feminization probably due to increased steroid aromatization.

5/10 members of a North African family (father, 2 male and 2 female siblings) had gynaecomastia, early growth and short final stature. The 8-year-old propositus had advanced bone age, facial acne, gynaecomastia, pubic hair and prepubertal testicular volume. Basal oestrone (E1) was elevated (670 pmol/l) and increased with adrenocorticotropic hormone (ACTH; 826 pmol/l). After human chorionic gonadotropin stimulation testosterone (T) responded normally whereas E1 and oestradiol (E2) remained unchanged. ACTH-dependent adrenal feminization was confirmed by a transient reduction of breast tissue following dexamethasone or cypropterone acetate treatment. Testolactone increased T/E2 (from 5.6 to 20.3) and A/E1 (from 3.4 to 31.4) ratios and temporarily reduced the breast tissue. In conclusion, this is a familial type of adrenal feminization with increased adrenal androgen aromatization. This is the first time that male-to-male and male-to-female transmission has been reported.

Adrenal Glands↗
PubMed1992

Growth response to recombinant human growth hormone of mammalian cell origin in prepubertal growth hormone-deficient children during the first two years of treatment.

In five clinical studies performed in Austria, France, the FRG, Italy, Switzerland, the UK and the USA, 304 growth hormone (GH)-deficient children were treated with recombinant human GH (rhGH) of mammalian cell origin. Two hundred and twenty-five patients were previously untreated (naive patients), and 79 were transferred from pituitary hGH after interruption of therapy for at least 6 months (transfer patients). Two treatment protocols, differing in both dose and frequency of injections, were used: (1) a dose of 0.6 IU/kg body weight per week was administered in 3 s.c. injections to 203 patients (178 naive, 25 transfer; group 1); and (2) a dose of 0.45 IU/kg body weight per week was administered in 7 s.c. injections to 101 patients (47 naive, 54 transfer; group 2). After 1 and 2 years of treatment, 143 and 109 naive, and 51 and 46 transfer patients, respectively, were still prepubertal, and their data were analyzed for efficacy. During the 1st year of treatment, both naive and transfer patients on daily injections (group 2) demonstrated better growth than those on 3 injections per week (group 1), with height velocities (HVs) of 10.6 +/- 2.7 cm/year (group 2) versus 8.6 +/- 2.0 cm/year (group 1) for naive patients (p < 0.001), and 9.9 +/- 1.9 cm/year (group 2) versus 7.2 +/- 2.7 cm/year (group 1) for transfer patients (p < 0.001). The corresponding changes in height standard deviation score (delta H SDS) for chronological age (CA) were +1.3 +/- 0.6 (group 2) versus +0.8 +/- 0.5 (group 1) for naive patients (p < 0.01), and +1.1 +/- 0.3 (group 2) versus +0.6 +/- 0.4 (group 1) for transfer patients (p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Recent aspects of steroid biosynthesis in male sex differentiation. Clinical studies.

Recent discoveries in molecular biology have much clarified the regulation and function of steroid-converting enzymes. Most progress has been made in the area of cytochromes, which regulate the side chain cleavage of cholesterol (P-450 SCC) and the 17 alpha-hydroxylase and 17,20-desmolase (or 17,20-lyase) activities (P-450 17 alpha), as well as in 3 beta-hydroxysteroid dehydrogenase. Nevertheless, there are some discrepancies between fundamental knowledge and clinical experience, which are difficult to understand: why is it for example possible that cases with 'pure' 17 alpha-hydroxylase or 17,20-desmolase deficiency exist, when there is only one cytochrome regulating both steps? After a brief review of clinical and biochemical findings in the various defects of testosterone biosynthesis, a case is discussed, which is of interest in this respect. This XY patient with female external genitalia, who has been shown to have compound heterozygous mutations, had 'pure' 17,20-desmolase deficiency up to adolescence, but additional 17 alpha-hydroxylase deficiency with hypertension developed thereafter. From this observation, it has to be concluded that as yet unknown, possibly age-dependent modulating factors exist, which influence the activity of the cytochrome. Also the estrogen replacement given to the patient might have played a role in this change.

Adrenal Hyperplasia, Congenital↗
PubMed1992

Interrelations between growth hormone and sex hormones: physiology and therapeutic consequences.

Animal experiments, analysis of growth hormone (GH) secretion in the human, studies on the synergistic metabolic effects between GH and sex hormones using the stable isotope 15N, and long-term growth evaluation of patients with GH and gonadotrophin deficiency treated with testosterone and hGH show that biologically important interrelations exist between GH and sex hormones. They are operative not only at the pituitary and gonadal levels but also in peripheral tissues, where sex hormones modify the metabolic and growth-promoting effects of GH. GH is also important for an optimal androgenic effect of testosterone in development of secondary sexual characteristics. Knowledge of these interrelations is not only of physiological interest, but also of practical clinical value.

Androgens↗