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L Tharandt

Publications and source records attributed to L Tharandt.

At least 19 recordsLinked to original sources
PubMed1999

DNA aneuploidy as a specific marker of neoplastic cells in FNAB of the thyroid.

OBJECTIVE: To investigate whether DNA image cytometry (ICM) could be of value in the specific identification of neoplastic cells in cytologic specimens of the thyroid. STUDY DESIGN: FNABs of thyroid from 162 patients with different benign and neoplastic diseases were investigated. Nuclear DNA content in thyroid cells was measured after Feulgen staining using a TV image analysis system. Data were correlated with clinical and histologic patient follow-up. The occurrence of abnormal DNA stemlines was used as a marker for aneuploidy and thus for neoplasia. RESULTS: None of the 89 cases without tumor cells revealed DNA aneuploidy. An abnormal DNA stemline was found in 55% of histologically proven benign thyroid tumors (follicular or oncocytic adenomas) and in 59.5% of malignant tumors. The positive predictive value of DNA aneuploidy in FNABs of the thyroid for neoplasms was 100%. The negative predictive value of DNA nonaneuploidy for the prediction of tumor-free histologic or clinical follow-up was 79.4%. CONCLUSION: DNA image cytometry may be helpful in the specific identification of neoplastic follicular cells. DNA ICM on FNABs of the thyroid is an additional tool to achieve early identification of patients with nodular lesions of the thyroid that have to be operated on. DNA euploidy excludes the presence of neither malignancy nor neoplasia.

Adolescent↗
PubMed1987

Metabolism of GnRH in man: influence of estrogens.

UNLABELLED: To clarify the influence of estrogens on the metabolism of gonadotropin-releasing hormone (GnRH), we studied the metabolic clearance rate (MCR) of GnRH (MCRGnRH), and the serum levels of luteinizing hormone (LH), follicle-stimulating hormone (FSH), estradiol and testosterone (total and free fraction) in 9 sexually mature men and 7 women under basal conditions and after treatment with the antiestrogen tamoxifen (2 X 10 mg/day p.o.) for 7 days. In women, the medication was started on day 7 +/- 1 of their menstrual cycles. To calculate the MCR, synthetic GnRH was continuously infused (1.53 micrograms/min) and its serum levels were measured by a radioimmunoassay. During tamoxifen treatment we observed a small but significant decrease in the MCR in men (455 +/- 48 to 357 +/- 46 ml/min/1.86 m2), whereas the known cyclic increase in the MCR in women was blunted (1,769 +/- 147 to 1,558 +/- 119 ml/min/1.86 m2). There was a small but significant increase in LH levels in women (8.3 +/- 2.1 to 11.5 +/- 2.5 mU/ml). LH and testosterone levels in men, and FSH and estradiol levels in both sexes did not change significantly. CONCLUSION: (1) estrogens regulate the MCRGnRH either directly or by changing gonadotropin levels, but the effect is only slight; (2) an enhanced metabolism of GnRH may contribute to the feedback of estrogens on the secretion of gonadotropins, and (3) the sex-specific difference of the MCR is presumably not caused by estrogens.

Adolescent↗
PubMed1984

Regulation of luteinizing hormone release by pulsatile and continuous administration of gonadotropin-releasing hormone to superfused rat and hamster pituitary cells.

Regulation of LH release by GnRH was studied in superfused anterior pituitary cells from 30-day-old female rats or hamsters. Dispersed cells were cultured 4-6 days on Cytodex beads, then loaded into water-jacketed columns, and perfused with medium (0.5 ml/min) at 37 C. Three-minute fractions of effluent were assayed for LH by RIA. LH release was dose related between 10(-10) and 10(-7) M GnRH. Rat and hamster cells released LH at peak rates of 11.3 and 12.5 ng/(min X 10(6) cells), respectively, when first exposed to 10(-8) M GnRH. Short pulses (6 min) of 10(-8) M GnRH given at 30-min intervals had little effect on the rate of LH release by rat pituitary cells; however, if the interpulse interval was reduced to 12 min, release declined 72% by the fifth pulse. In contrast, pulses of 10(-6) M GnRH at 30-min intervals desensitized rat cells. Hamster cells were desensitized by 10(-8) M GnRH after a single pulse regardless of whether a second pulse was given 30 min or 2.5 h later. Similar desensitization also occurred at other doses (10(-9) and 10(-6) M). After five pulses at 30-min intervals, the LH release rate in hamster cells was depressed 65%. Release was depressed 80% by pulses at 12-min intervals. Thus, in rats, desensitization is both frequency and dose dependent, whereas in hamsters, it is independent of frequency and dose. Stimulation with 10(-6) M GnRH pulses completely overcame desensitization in both species. Continuous exposure of anterior pituitary cells to 10(-8) M GnRH caused an initial rapid LH release, followed by a steady decline in the rate of release from peak rates to baseline levels by 2.5 h in both species. A 6-min, 10(-6) M GnRH pulse given immediately after a 3-h 10(-8) M GnRH exposure rapidly stimulated the cells to release LH at rates up to 192% of initial rates. When these pulses were continued at 30-min intervals, additional desensitization occurred. This overcoming of desensitization shows that desensitized anterior pituitary cells are not refractory to GnRH and suggests that the GnRH regulation of LH release may involve more than one GnRH receptor-mediated phenomenon.

Animals↗
PubMed1982

[The Houssay phenomenon in man (author's transl)].

Marked insulin sensitivity, accompanied by unusual hypoglycaemic symptoms, was observed in three patients with juvenile diabetes mellitus. All three had anterior hypopituitarism, developing post-partum in two, a craniopharyngioma being the cause in the third. These are thus three examples of the Houssay phenomenon of which only 37 cases have previously been described.

Adult↗
PubMed1981

[Endocrinologic findings in Crohn's disease].

In 45 patients with radiologically and endoscopically/histologically proven Crohn's disease the partial functions of the anterior pituitary gland were measured prior to steroid therapy. No deficiencies were observed with respect to cortico-, thyro-, gonado-, and somatotropic functions. In 25 out of 40 patients (63%) the typical diurnal rhythm of cortisol secretion was absent when assessed by a distinctly elevated 6 p.m. cortisol serum level. In about one fourth of 22 patients T3-RIA was reduced, indicating deficiency of conversion from T4 to T3. Six (43%) out of 14 males showed reduced basal testosterone levels at 8 a.m. and 6 p.m. which, in 4 out of 14 cases, did not increase sufficiently in response to HCG. The basal LH-level was elevated in 9 (50%) of 18 males. The lack of diurnal rhythm of cortisol secretion and primary insufficiency of Leydig's cells did not correlate with the activity of the disease.

Adolescent↗
PubMed1981

The metabolic serum clearance of GnRH. Relationship to age, sex and male puberty.

UNLABELLED: The MCR of constantly infused synthetic GnRH (1.53 micrograms/min) was studied in relation to age, sex, and male sexual maturation. GnRH was determined by a radioimmunoassay using a specific GnRH antiserum and 125I-GnRH, prepared by the chloramine T technique and purified on Sephadex G 25. Serum LH and FSH were measured by RIA. The results (mean values +/- SEM) of MCR expressed here as ml/min/1.86 m2 showed a statistically significant difference: infants (6-13 yrs) 1170 +/- 79, sexually mature males (22-29 yrs) 639 +/- 28, elderly men (64-79 yrs) 520 +/- 38, sexually mature females (20-24 yrs) follicular phases: 1354 +/- 90, luteal phases: 1736 +/- 242, postmenopausal women (53-74 yrs) 598 +/- 45. We found a linear negative correlation between serum LH and MCR of GnRH in both sexes. During male puberty the MCRLH-RH decreased simultaneously to the stages of pubic hair development. IN CONCLUSION: 1) The MCR of GnRH is a function of age, sex, and sexual maturation, 2) its negative linear correlation with LH in both sexes indicates that the MCR presumably reflects endogenous GnRH levels, 3) the MCRGnRH seem to be subject to endocrine regulation.

Adolescent↗
PubMed1980

Effects of prolactin suppression on hypogonadism im patients on maintenance haemodialysis.

UNLABELLED: The effects of prolactin (Prl) suppression by bromocriptine (BC) on impaired sexual function were studied in 47 male patients on maintenance haemodialysis (HD). All patients had normal serum zinc levels. Before treatment, 14 of 47 patients had moderate hyperprolactinaemia (not due to medication), 24/39 patients had elevated LH levels, 13/34 patients had elevated FSH levels, 26/44 patients had decreased serum testosterone levels and 18/24 patients were oligo-/azöospermic. Bromocriptine was given in doses of 1.25 to 2.5 and 5.0mg/day and each of these doses was maintained for two weeks. Seventeen patients discontinued treatment within the first few days of BC treatment, because of postural hypotension and/or nausea. Fourteen other patients had to be excluded because of poor compliance. On treatment, as little as 1.25mg of BC/day normalised serum Prl, and 2.5mg of BC/day decreased Prl below the lower limit of normal. Neither gonadotrophins nor serum testosterone levels changed significantly during the six weeks of BC treatment. IN CONCLUSION: 1. neither normalisation of moderate hyperprolactinaemia in patients on HD, nor 2. suppression of serum Prl into the subnormal range affects serum gonadotrophin and testosterone levels. 3. These results do not support the hypothesis that moderate hyperprolactinaemia in our patients on HD is an important factor in the development of hypogonadism.

Adult↗
PubMed1979

Binding of luteinizing hormone releasing hormone to human serum proteins--influence of a chronic treatment with a more potent analogue of LH-RH.

Binding of 125I-LH-RH and its analogue, 125I-6-D-Leu-10-Des-Gly-Ethylamide-LH-RH (6-D-LH-RH) in male serum was studied in 10 healthy males and in 11 patients with idiopathic gonadotropin deficiency (IGD) before and during treatment with 6-D-LH-RH. Using either equilibrium dialysis (A) or ethanol precipitation (B) 13.57 +/- 0.69% (A) or 19.32 +/- 1.73% (B) of LH-RH and 7.12 +/- 0.86% (A) or 14.56 +/- 1.06% (B) of the analogue were in the bound form, without difference between normal subjects and IGD. Capacity of this binding was high (greater than 9 less than 18 mu-Mol LH-RH/0.06 mMol of protein), affinity very low, and the binding almost completely disappeared following removal of albumins by affinity chromatography. Chronic treatment with 6-D-LH-RH did not alter these binding characteristics. These observations suggest non specific albumin binding of LH-RH in male serum and stress the role of this decapeptide as a rapid modulating regulator of gonadotropin secreting system.

Blood Proteins↗
PubMed1979

Immunoreactive somatomedin B in acromegaly and in Turner's syndrome.

Serum somatomedin B was measured by radioimmunoassay in forty-seven normal subjects, twenty-nine patients with acromegaly before and twenty-four after treatment, and eighteen patients with Turner's syndrome. Somatomedin B levels were significantly elevated in untreated acromegaly and in Turner's syndrome compared with the control group; they decreased following treatment of acromegaly. Because of the overlap between the groups, little information could be obtained from single somatomedin B estimations, which could, therefore, not replace dynamic tests of growth hormone secretion. No correlation between growth hormone and somatomedin B in acromegaly was detected; however, somatomedin B appeared to be related to the insulin response during the oral glucose tolerance test. In Turner's syndrome, no relationship between somatomedin B and insulin production, urinary oestrogen excretion, growth hormone secretion, gonadotrophin levels, age or height was found. The reason for the raised somatomedin B levels in Turner's syndrome remains at present unknown.

Acromegaly↗
PubMed1979

Gel filtration studies of serum growth hormone in acromegaly following bromocriptine administration.

Sera of 7 patients with active acromegaly were fractionated by Sephadex G-100 chromatography and the effects of bromocriptine on the concentrations of total growth hormone (hGH) and its different molecular forms studied. Three immunoreactive peaks were observed, corresponding to molecular weights of about 20,000 ('little hGH'), 40,000 ('big hGH'), and more than 100,000 ('big big hGH') Following bromocriptine administration, there was significantly more reduction of 'little hGH' than of 'big big hGH'. Careful interpretation of these changes is required in view of the possible influences of sample storage and handling on hGH heterogeneity. We suggest that either bromocriptine acts differentially on the release of 'little' and 'big big hGH', or that these components differ in their metabolic half-life. However, even the suppression of 'little hGH' is insufficient to explain the clinical response of the disease to bromocriptine.

Acromegaly↗
PubMed1979

[Investigations on the utilization of D-gluconate and D-glucono-delta-lactone in the metabolism of the normal and alloxan diabetic rat (author's transl)].

Radioactivity was measured in the blood of normal and alloxan diabetic rats, after the oral administration of [U-14C]gluconate and [U-14C]glucono-delta-lactone, respectively. Radioactivity was also measured in the intestinal contents and feces 5 h after ingestion of the radioactive materials, It was concluded that the lactone is better absorbed from the intestine than the gluconate anion. According to this enhanced membrane permeation and the higher concentration reached in blood, the space of distribution of the lactone is larger than that of gluconate (50 and 41% of body weight, respectively); a higher retention in tissues and a greater loss in urine was also observed after administration of the lactone. Incorporation into liver glycogen is also higher from the lactone than from gluconate after oral administration, particularly in diabetic animals. The initial deficit in the oxidation of gluconate compared to that of the lactone, caused by a lag period of 7 and 4 h, respectively, is completely compensated during the following 8-9 h. The oxidative turnover of gluconolactone and of gluconate is significantly enhanced in diabetic animals. The better utilization in diabetic metabolism is in part explainable by a rise of glycolytic intermediates in the liver, which are decreased in starvation and diabetes. The limiting step of gluconate metabolism is the initial phosphorylation. Possibilities are discufor the dietetic use of gluconic acid in the form of an apolar derivative (lactone, ester).

Animals↗
PubMed1979

[Pure gonadal dysgenesis. Case report with unusual anatomical and endocrine findings].

The syndrome of pure gonadal dysgenesis (PGD) cannot always easily be distinguished from other disorders of gonadal development. Relations are evident with Turner's syndrome, females with hypoplastic ovaries, male pseudohermaphroditism, mixed gonadal dysgenesis and the vanishing testes syndrome. The case is reported of a 40 year old female with primary amenorrhea, alopecia, eunuchoid features, XY karyotype with normal breast development and sexual hair after estrogen therapy. On laparotomy streak ovaries were found at ovarian site. Pathohistological examination revealed on the left side wolffian duct remnants such as ductuli deferentes and epididymis besides sparse Leydig-(hilus-)cells and on the right side only a rudimentary fallopian tube with subendothelial accumulation of hyperplastic Leydig-(hilus-)cells. Serum-testosterone elevation above the normal female range (630 ng/dl) persisted following gonadectomy (151 ng/dl). Ectopic Leydig-(hilus-)cells were regarded responsible for the continuing testosterone production. The present case lies on borderline between PGD and mixed gonadal dysgenesis because remnants of wolffian duct derivatives suggest unilateral fetal testicular activity; classification as PGD however was justified in purely female body features and lacking evidence of testicular tissue.

Adult↗