Biomedical subjects

H Stolecke

Publications and source records attributed to H Stolecke.

At least 19 recordsLinked to original sources

PubMed1994

Receiver-operated characteristic curve analysis of two algorithms assessing human growth hormone pulsatile secretion (PULSAR, CLUSTER): comparison of peak detection efficacy.

Computer-based peak identification algorithms reduce observer bias in the analysis of pulsatile hormone secretion. With increasing peak detection stringency, an algorithm will detect varying proportions of true-positive and false-positive peaks, determining its receiver-operated characteristics (ROC). To demonstrate that ROC curve analysis can characterize algorithm performance, we analyzed growth hormone (hGH) profiles from 94 children obtained with different hGH assay techniques [radioimmunoassay (RIA), immunoradiometric assay (IRMA)] at different sampling intervals (group A: 1 h/RIA; group B: 1 h/IRMA; group C: 20 min/RIA; group D: 20 min/IRMA), using the PULSAR and CLUSTER algorithms. The area under the ROC curve (AUC) was taken to compare the efficacy of both algorithms over a range of peak recognition stringency thresholds kept constant between algorithms, using hGH noise series for threshold calibration and the results of multiple visual inspection as reference standards. AUC by PULSAR ranged from 0.926 (group C) to 0.961 (group A), indicating good algorithm performance. AUC by CLUSTER ranged from 0.869 (group B) to 0.916 (group D) in the 20-min series, decreasing to 0.756 (group C) and 0.868 (group A) in the 1-hour series. At lower sampling intensity, significant discordant sensitivity existed between algorithms for RIA (p < 0.001) and IRMA (p < 0.0026). When adjusted to a high, assay-specific, comparable stringency, and employed on 20-min sampling hGH data, both the CLUSTER and PULSAR algorithm operated at a similarly high peak detection efficacy. The PULSAR algorithm appears to be more robust when hGH series with lower sampling intensities are analyzed.(ABSTRACT TRUNCATED AT 250 WORDS)

Algorithms↗

PubMed1991

Severe hypoaldosteronism due to corticosterone methyl oxidase type II deficiency in two boys: metabolic and gas chromatography-mass spectrometry studies.

Infection-triggered, life-threatening salt-loss and hyperkalaemia developed in two male infants with wasting, inappropriately low plasma aldosterone concentrations and elevated plasma renin activity. The presumptive diagnosis of a defective terminal step in aldosterone biosynthesis was made by the presence of large amounts of 11-dehydrotetrahydrocorticosterone and its 18-hydroxylated metabolite (18-OH-THA), free 18-hydroxycorticosterone (18-OH-B) and 18-hydroxytetrahydrocorticosterone in the urine of both patients. The diagnosis of corticosterone methyl oxidase type II (CMO II) deficiency was confirmed by an elevated urinary 18-OH-THA to tetrahydroaldosterone ratio in one boy and by an elevated plasma 18-OH-B to aldosterone ratio in the other boy. Unknown steroids responsible for the salt-loss were not identified. Sodium supplementation but not short-term high dose oral 9 alpha-fluorcortisol (FF) normalized the hyponatraemia in one patient, in whom sodium (Na+)/potassium (K+) co-transport was decreased. Both patients eventually received long-term FF treatment to prevent impairment of longitudinal growth caused by chronic salt-loss. The diagnosis of CMO II deficiency should always be confirmed by elevated precursor-product ratios in urine or plasma, using radioimmunoassays with prior chromatographic separation. Metabolic studies as the short-term response of serum Na+ to high dose FF may not be helpful in differentiating aldosterone biosynthetic defects from end-organ resistance to mineralocorticoids.

Cortisone↗

PubMed1989

Discordant immune and growth response to pituitary and biosynthetic growth hormone in siblings with isolated growth hormone deficiency type IA.

Two brothers with familial isolated growth hormone deficiency type IA homozygous for the same 6.7 kb deletion on chromosome 17 including the growth hormone gene were intermittently treated with various forms of hGH for more than 7 years. While the elder brother (Patient 1) showed a good growth response to pituitary hGH, the younger one (Patient 2) developed high titre growth blocking hGH antibodies early in the course of treatment and grew only 2.2-3.9 cm/year on a hGH dose of 12-26 IU/m2 per week. When the younger brother was changed to a higher dose (33 IU/m2 per week) of biosynthetic methionyl hGH he had striking catch-up growth and he has subsequently maintained a height velocity of 10.0 cm/year for the last 2 years. During this time his antibody titres have decreased over 1000-fold. These findings demonstrate that therapy with biosynthetic methionyl hGH may provide an effective form of treatment for subjects with isolated growth hormone deficiency type IA who do not grow in response to native hGH, and imply that biosynthetic methionyl hGH may be less antigenic than pituitary derived hGH.

Adolescent↗

PubMed1988

Age-related changes in adrenal size during the first year of life in normal newborns, infants and patients with congenital adrenal hyperplasia due to 21-hydroxylase deficiency: comparison of ultrasound and hormonal parameters.

An adrenal size index (ASI) was specifically designed to improve ultrasound evaluation of adrenal size in the 1st year of life. In 84 newborns and infants, ASI and plasma dehydroepiandrosterone sulphate (DHEA-S) concentrations were determined to study in vivo changes in adrenal size and cortical zonal composition. ASI was higher (P less than 0.0001) in the first 2 postnatal weeks (median 60.5 mm2) than in the rest of the first year (median 39.6 mm2) and showed a negative correlation with chronological age (r = -0.41). A positive correlation existed between DHEA-S concentrations and ASI (r = 0.29) as well as ASI relative to body weight (r = 0.57). These data and changes in gland echogenicity are consistent with histopathological observations that the early decrease in adrenal size is due to involution of the fetal zone. In four patients with congenital adrenal hyperplasia (CAH) due to 21-hydroxylase (21-OHase) deficiency, ASI and plasma concentrations of pre-defect steroid were determined. Two patients with severe salt loss had markedly elevated ASI, which returned to normal during treatment. Two patients without severe salt loss had pretreatment ASI in the upper normal range, which decreased with treatment. Our findings indicate that ASI is useful in assessing physiological changes in adrenal size and, in conjunction with DHEA-S determinations, in adrenal cortex composition. ASI may aid in the early diagnosis of the salt-losing variety of 21-OHase deficiency. ASI is an instantaneously available tool which, in addition to biochemical and clinical data, can be used to monitor treatment of 21-OHase deficiency.

Adrenal Glands↗

PubMed1988

[Significance of endocrinology in clinical pediatrics].

Hormones are involved essentially in the general biological program of growth and differentiation. An important aim of clinical endocrinology is to recognise variants of normal development which should be evaluated against pathological conditions. As a context, growth in length and pubertal progress may be seen as "key-words" leading to special diagnostic procedures. With regard to some endocrine disorders, data being of principal and actual importance and dealing with diagnosis and therapy, were discussed shortly.

Child↗

PubMed1987

Short-term effects of testolactone compared to other treatment modalities on longitudinal growth and ovarian activity in a girl with McCune-Albright syndrome.

In a 6 1/2-month-old girl with McCune-Albright syndrome, gonadotropin-independent isosexual precocity and recurrent ovarian cysts, the short-term effects of surgical therapy, cyproterone acetate (120 mg/m2/d), combined medroxyprogesterone acetate (10 mg/d), and spironolactone (50-75 mg/d) treatment, and testolactone (40 mg/kg/d) were evaluated sequentially. No significant reduction of cyst frequency was achieved with any of the medical treatments. The rate of bone maturation (delta BA/delta CA) was increased and the height standard deviation score (SDS) for bone age as a potential indicator of final height was decreased with surgical treatment alone and combined medroxyprogesterone acetate and spironolactone. Both parameters normalized with cyproterone acetate and testolactone. Height velocity SDS, however, was higher with testolactone (0.97 vs. 0.45).

Androgen Antagonists↗

PubMed1987

[Current aspects of the endocrinology of female puberty].

Some important aspects of current knowledge on female pubertal development are reviewed specially regarding hormonal events. Pulsatile hypothalamic (LHRH-) activity occurs early in childhood and shows a specific development after the onset of puberty, resulting in progressive enhancement of gonadal estrogen and gestagen secretion finally until the menstrual cycle is established by specially characterized hormonal controls. In the ovary an "internal metabolic milieu" is necessary for normal adult function. Some pathophysiological problems and clinical syndromes leading to functional or systemic developmental failure are discussed shortly.

Adolescent↗

PubMed1986

Cushing disease: successful preoperative lateralization of an ACTH-producing pituitary microadenoma by simultaneous bilateral inferior petrosal venous sinus sampling with corticotropin-releasing hormone stimulation.

A 5 10/12-year-old girl with clinical and laboratory signs of endogenous hypercortisolism had evidence of ACTH hypersecretion in a standardized dexamethasone suppression test but had surprisingly low plasma ACTH concentrations before and after ovine corticotropin releasing hormone (oCRH) stimulation. To establish the diagnosis of pituitary disease and to localize the suspected microadenoma, we performed bilateral simultaneous inferior sinus petrosus blood sampling under CRH stimulation (oCRH 1 microgram/kg as an i.v. bolus). No major side effects were noted. Inferior petrosal blood ACTH concentrations did not differ from peripheral blood under basal sampling conditions but were higher in the effluent of the left half of the pituitary 5 min after oCRH stimulation. During transsphenoidal exploration of the sella an ACTH-producing microadenoma was removed from the left portion of the anterior pituitary gland. Signs of hypercortisolism remitted after surgery. Simultaneous bilateral sinus petrosus blood sampling under oCRH stimulation is a useful lateralization procedure even with small ACTH-producing adenomas. This technique may help to avoid unsuccessful surgical exploration in children with Cushing disease.

Adenoma↗

PubMed1979

[Endocrine disorders in children with neurofibromatosis von Recklinghausen (author's transl)].

Endocrine disturbances have been studied in 4 children with neurofibromatosis von Recklinghausen, aged 5.0-10.5 years. Hypothalamic precocious puberty was seen in three boys; growth hormone deficiency was diagnosed in a girl. After TRH stimulation one boy and the girl showed a diminished TSH-response. Another boy showed a relatively high basal level of TSH and an elevated TSH-response to TRH. All children were euthyroid. Two boys had a hyperprolactinemia even under basal conditions; the one with elevated TSH-response showed an excessive response of prolactin as well. In all our patients a suprasellar tumor caused the endocrine disorders described.

Astrocytoma↗

PubMed1978

Thyroid function in children with growth hormone deficiency, either idiopathic or caused by diseases of the central nervous system.

Thyroid function was assessed in thirty two patients with growth hormone deficiency (GHD) by clinical examination and by measurement of T4-levels, free T4-indices, basal TSH values and TSH responses to TRH (100 mu/m2). Sixteen patients (50%) were hypothyroid. In thirteen patients, the endocrine disorders were considered to be of hypothalamic origin. Ten of them showed prolonged responses to TRH and in the other three the responses were exaggerated. In three patients hypothyroidism was due to a primary pituitary disorder. Sixteen patients were euthyroid although three of them showed impaired TSH responses. In the cases with idiopathic hypopituitarism (n = 20) there a high incidence of abnormal births in the children with additional hypothalamic hypothyroidism, but not in the euthyroid patients. It is concluded that in patients with previous breech or vacuum extraction delivery, growth hormone deficiency when combined with hypothalamic hypothyroidism may be due to birth trauma.

Adolescent↗

PubMed1978

Endotoxin stimulated nitroblue-tetrazolium (NBT)-test in patients with hypoparathyroidism, pseudohypoparathyroidism and other forms of hypocalcemia.

Endotoxin-stimulated NBT-tests were carried out in 15 patients with hypocalcemia of varying etiology and in 14 normocalcemic children free of infection. In the control group the formazan cell percentage (FCP) was 73.8 +/- 1.6% (range 63% to 83%). In 5 patients with hypoparathyroidism or pseudohypoparathyroidism the FCP before treatment was lower than normal. Vitamin D3 therapy produced a rapid increase of serum calcium but normalisation of NBT-test was only achieved after a latent period of one or more months. Patients with hypocalcemic rickets and children with an acute relapse of the nephrotic syndrome also showed abnormal results. The clinical significance of the NBT-test in hypocalcemic conditions is discussed.

Adolescent↗

PubMed1978

[Virilizing adrenal cortical tumors in childhood (author's transl)].

We report on four patients, aged seven months to seven years, with virilizing adrenal cortical tumors. Diagnosis was made by clinical and laboratory data. Tumor localisation was achieved preoperatively in three patients. In two patients both androgen and glucocorticoid excretion were elevated. In three patients histological examination showed a carcinoma, in one patient an adenoma was suggested. There were no metastases. In two patients surgical removal was followed by cytostatic therapy, in one of them additional irradiation treatment was carried out. This child died 10 1/2 years later from a metastasizing renal cell carcinoma which originated from the kidney being situated in the irradiated area.

17-Ketosteroids↗

PubMed1978

Endocrine dysfunction in the diencephalic syndrome of emaciation in infancy.

A 10-month-old boy with the clinical features of the diencephalic syndrome of emaciation due to a suprasellar spongioblastoma is described. The patient showed high basal levels of growth hormone (GH greater than 80 muU/ml on several occasions). In addition, elevated concentration of plasma testosterone (125.5 ng/100ml) was combined with a relatively high LH-increase to LHRH (45.6 mU/ml). After completion of irradiation basal GH-levels had been normalized, and GH responses to insulin induced hypoglycemia (IIH) and propranolol-glucagon (PG) were adequate. Complete clinical remission of emaciation occurred soon after radiation therapy and went parallel with the normalization of GH-regulation.

Astrocytoma↗

PubMed1977