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Biomedical subjects

F Raue

Publications and source records attributed to F Raue.

At least 163 records · Page 9Linked to original sources

[Clinical features and diagnosis of mild 3-beta-hydroxysteroid dehydrogenase deficiency in men].

3 beta-hydroxysteroid dehydrogenase (HSD) deficiency was demonstrated in six males, aged between 18 and 24 years, who had gynaecomastia, hypogonadism or infertility. The predominant laboratory finding was a striking elevation of dehydroepiandrosterone sulphate (DHEAS) levels. The diagnosis of HSD deficiency was confirmed by finding a marked rise in dehydroepiandrosterone (DHEA) and 17-hydroxypregnenolone levels. In contrast to these findings in late-onset enzyme deficiency, in four males with the classical form of 21-hydroxylase deficiency the only sign was a reduction in adult height. The prevalence of late-onset HSD deficiency in men is not known and may be more relevant in patients with gynaecomastia or abnormal gonadal function than has hitherto been realized.

17-alpha-Hydroxypregnenolone↗

[Hyperthyroidism caused by a hormone-producing follicular thyroid cancer].

A well differentiated carcinoma of the thyroid is usually less productive with respect to thyroid hormones than normal thyroid tissue. Very rarely, it happens though that a metastatic follicular carcinoma of the thyroid produces hyperthyroidism as the following example illustrates. In our patient with follicular thyroid carcinoma the radioiodine scan demonstrated an increased uptake of 123I in the right thyroid lobe but also in a lung metastasis, even before thyroidectomy. In contrast, the iodine uptake of the left - normal - thyroid lobe was suppressed. Following thyroidectomy the levels of the thyroid hormones were normal and only dropped into the hypothyroid range after the beginning of the therapy with radioiodine. Hence we conclude that the metastases of a thyroid carcinoma can attain the hormone secretion of a normal thyroid gland and take up more radioiodine than normal thyroid tissue.

Adenocarcinoma↗

Reversible desensitization of calcitonin secretion by repetitive stimulation with calcium.

The extracellular ionized calcium concentration (Ca2+) is a main regulator of calcitonin (CT) release. Calcium-induced CT secretion differs for acute versus long-term alterations of Ca2+. Using the rat C cell line rMTC 6-23 we have investigated the effect of repetitive stimulation by Ca2+ on CT release. After a Ca-induced initial rise of CT secretion, repetitive Ca stimulation led to a decline of CT release to unstimulated levels (after about 4 h). Reversing the high Ca2+ concentration (2.0 mM) to basal (1.1 mM) for 2 h and then increasing Ca2+ again resulted in a restored stimulatory action of Ca2+ (about 100% increase above the control). In contrast, repetitive stimulation with the dihydropyridine Ca channel agonist Bay K-8644 showed an unchanged stimulatory effect, as observed for the cAMP analog 8-bromo-cAMP, too. The results indicate that the reversible desensitization of Ca-induced CT secretion might be due to a modification of the voltage-dependent Ca channels proximal to or at the site of Bay K-8644 action.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗

Rhythmic oscillations of cytosolic free calcium in rat C-cells.

The relationship between stimulation of single C-cells (rMTC-6-23 cell line) with extracellular calcium, glucagon or 8-bromo-cAMP and fluctuations of intracellular free calcium concentration was studied. After pretreatment of rMTC cells with either 1 microM glucagon (30-60 min) or 1 mM 8-bromo-cAMP (5 min) [Ca2+]i started to oscillate when extracellular calcium was raised to 3 mM. These fluctuations in [Ca2+]i could be stopped by chelating the external calcium with EGTA or by adding calcium channel blockers. The voltage-dependent calcium channels in the plasma membrane seem to play a major role in maintaining the oscillations of [Ca2+]i.

8-Bromo Cyclic Adenosine Monophosphate↗

Calcitonin secretion and cyclic AMP-efflux from C-cells, stimulated by glucagon and either calcium or Bay K 8644.

The interaction of glucagon and either calcium or Bay K 8644 on calcitonin (CT)-release and cAMP-efflux was studied in a rat C-cell line, (rMTC 6-23). CT secretion was stimulated by glucagon up to 216%, ionized calcium (Ca++) up to 112%, and Bay K 8644 up to 81% above the control. The combination of glucagon with either Ca++ or Bay K 8644 resulted in an additive effect. cAMP-efflux was grossly incremented by glucagon (536 pmol/mg), slightly by Ca++ (11.6 pmol/mg) and not at all by Bay K 8644 (less than 3 pmol/mg). The combination of glucagon with either calcium or Bay K 8644 caused a reduction of the cAMP-increase obtained by glucagon alone. These data suggest complex interactions between the cAMP and the intracellular calcium-dependent pathway, but an additive effect of the two pathways on CT-release.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗

Modulation of calcitonin secretion by modification of calcium channels?

Voltage-dependent calcium channels (VDCC) regulating Ca++ influx through the cellular plasma membrane play a major role in the Ca(++)-induced calcitonin (CT) secretion. Using rat C-cells (rMTC 6-23 cell line), we have studied the effect of repetitive stimulation by either Ca++ (2 mM) or glucagon (10 microM) or epinephrine (10 microM) on CT secretion. Following a Ca(++)-induced initial rise, CT release declined to basal levels after about four hours despite high Ca++; addition of 10 microM glucagon to the "Ca++ desensitized C-cells" yielded the normal stimulatory effect of glucagon on CT release. Repetitive stimulation with glucagon showed a constant stimulatory action over an eight-hour period. In contrast, repetitive stimulation with 10 microM epinephrine caused an initial rise followed by a gradual decline of CT release over six hours. The observed desensitization of Ca(++)-induced CT secretion may be due to a modification of VDCC in C-cells. Whether or not the desensitization of epinephrine-induced CT release occurs independently of the regulation of VDCC remains unclear.

Animals↗

Postoperative pentagastrin-stimulated serum calcitonin concentrations in patients with medullary thyroid carcinoma: reoperations in patients with concentrations bordering the detection limit.

The case reports on two patients with medullary thyroid carcinoma show that even postoperatively stimulated serum calcitonin (CT) concentrations near the detection limit (using a polyclonal antibody against synthetic CT) can demonstrate persistent disease. Stimulated CT concentrations can be lowered to nondetectable levels by a second and third operation if a meticulous technique is used for dissection of the lymph compartments. The patient can then be assumed to be cured. Diagnostic accuracy at very low CT concentrations can be improved by selective venous catheterization with blood sampling for CT after stimulation.

Adult↗

[Internal medicine aspects of endocrine tumors. The hypophysis, epithelial bodies and adrenal glands].

Endocrine tumors are characterized by an overproduction of hormones leading to a typical clinical picture and/or by hormone deficiency induced by damage to the glands. Hormone deficiency or overproduction must be determined precisely, as must the morphology and localization of the tumor, before therapy starts. Hormone deficiency needs to be substituted. Specific therapies for hormone suppression and/or inactivation of the endocrine cells have been developed for some tumors, e.g., bromocriptine for prolactinoma, and o,p'-DDD for adrenocortical tumors.

Adrenal Gland Neoplasms↗

Diagnostic procedure before reoperation in patients with medullary thyroid carcinoma.

Elevated calcitonin (CT) levels after primary operation of the medullary thyroid carcinoma (MTC) are a reliable marker for persistence or recurrence of MTC, which first metastasizes in the neck or mediastinal region. The reliability of different localisation methods before reoperation in 28 patients with elevated CT levels was tested by comparing their diagnostic results with the actual finding at reoperation. The diagnostic procedures comprised ultrasonography of the neck, CAT-scan of the neck and mediastinum, selective venous catheterization with CT determinations, and fine needle biopsy. Due to the results of these tests 28 patients were reoperated 48 times. Histological evidence confirmed the presence of suspected tumor that had been diagnosed by: palpation 52%, ultrasonography 78%, CAT-scan 70%, selective venous catheterization 75%, fine needle biopsy 81%. Despite the fact that only 2 out of the 28 patients had normal CT levels postoperatively, the 5 year survival rate in reoperated patients (86%) improved compared to patients without reintervention (69%). For precise preoperative staging ultrasonography seems to be the most predictable and reliable method. The prognosis of MTC patients with elevated CT-levels in the follow-up period could be improved by frequent reoperations.

Adult↗

[Extraosseous calcification in juvenile dermatomyositis. The ineffectiveness of EHDP].

A now 20-year-old man was first diagnosed as having dermatomyositis when aged 12 years. At that time he had muscular weakness and heart failure followed a year later by heterotopic calcifications. For over seven years he was treated with corticoids, at times also with azathioprine or methotrexate. Nonetheless the calcifications progressed. Because of the extensive calcifications, predominantly of the extremities, he is severely disabled and has been confined to a wheel-chair. For one year he was treated with EHDP (1-hydroxyethylidenediphosphonate), up to 16 mg/dl per day. In addition he received prednisolone (10 mg/d) and azathioprine (100 mg/d). But radiologically there has been further slight progression of the calcifications, indicating that EHDP has been ineffective in this patient.

Adult↗

Down-regulation of calcitonin receptors in T47D cells by internalization of calcitonin-receptor complexes.

T47D cells possess specific calcitonin (CT) receptors and a CT-responsive adenylate cyclase. Internalization of part of their CT receptors has been suggested. At 37 degrees C, bound 125I-labelled salmon CT (sCT) becomes increasingly resistant to acid washing, which can remove surface-bound hormone, thus indicating internalization. Monensin and chloroquine, which raise the pH of the lysosomes and thereby inhibit cellular processing of endosomes, inhibit the decrease of total bound activity seen in the controls. Acid-resistant (internalized) activity increases to the levels of total binding. Preincubation with sCT leads to a loss of specific binding. Recovery of CT binding is prevented by monensin, which also inhibits transport of cellular proteins to the cell membrane. Recovery is not influenced by chloroquine. As chloroquine prevents recycling, we conclude that after binding of CT the receptors are internalized, transferred to a lysosomal compartment, and degraded intracellularly without recycling. All receptors seem to undergo internalization. Desensitization to CT in T47D cells is at least partly mediated by intracellular metabolism of CT receptors.

Chloroquine↗

Enhanced calcitonin secretion in the rat after parathyroidectomy and during chronic calcium deprivation.

The thyroidal content of calcitonin (CT) and the serum calcitonin responses to acute hypercalcaemia were studied in female rats during chronic hypocalcaemia induced by parathyroidectomy (PTX), a low calcium (Ca) diet, or both. The thyroidal CT content of the PTX animals 50 days after surgery was twice that of intact rats. An acute intraperitoneal (i.p.) calcium load on day 50 after PTX resulted in an increase in serum CT twice as large as that observed in control animals. Reversal of the chronic hypocalcaemia with 1,25(OH)2D3 resulted in a reduction in thyroidal CT as well as a depression of the calcium-induced CT response. In each case the values were similar to those observed in normocalcaemic controls. A low calcium diet increased the thyroidal CT content in intact rats and induced a further increase in PTX rats. The CT response to an acute Ca load was exaggerated by a low calcium diet in intact as well as in PTX rats. These results suggest that in the rat chronic hypocalcaemia enhances CT storage and secretion.

Animals↗

Procollagen-III peptide serum levels in Paget's disease of the bone.

A commercially available radioimmunoassay kit was used to determine aminoterminal procollagen-III peptide (pNcoll III) serum levels in patients with Paget's disease of the bone and control subjects. In patients with Paget's disease pNcoll III concentrations were significantly elevated. They decreased to varying degrees under chronic therapy with human and salmon calcitonin, disodium ethane 1-hydroxy 1,1-diphosphonate (EHDP), or a combination therapy of EHDP and human calcitonin. The results were compared with the effect on traditional biochemical markers of disease activity: serum alkaline phosphatase and urinary hydroxyproline excretion, both of which reacted more acutely to the various therapies than pNcoll III, although pretreatment correlations were close. The most probable source of pNcoll III is not the Pagetic bone per se, but the vascular, fibrous connective tissue replacing normal bone marrow.

Alkaline Phosphatase↗

[Katacalcin--a new tumor marker in C-cell cancer of the thyroid gland].

Katacalcin (KC) is situated on the C-terminal side of the procalcitonin molecule and is cleaved like calcitonin (CT) from this precursor peptide. Serum levels of KC were measured in 22 patients with C-cell carcinoma with a specific and sensitive radioimmunoassay (normal range, less than 0.1-0.15 ng/ml). Basal serum KC values in C-cell carcinoma patients were 0.32-290 ng/ml. There was a good correlation between KC and CT (r = 0.98, P less than 0.001). Serum KC, as well as CT, markedly increased after pentagastrin and calcium infusion. KC and CT were secreted in nearly equimolar amounts. During selective venous catheterization, KC and CT levels were increased in serum samples from veins draining tumor masses, which could be confirmed operatively. During the follow up, KC and CT measurements correlated well to the stage of disease. KC could be immunohistologically localized in C-cell carcinoma tissue. As a tumor marker, katacalcin is likely to be as useful as calcitonin in C-cell carcinoma.

Calcitonin↗

Neuron-specific enolase in medullary thyroid carcinoma: immunohistochemical demonstration, but no significance as serum tumor marker.

Neuron-specific enolase (NSE) is an enzyme detectable in nervous and neuroendocrine tissue. Increased serum levels of NSE are found in small cell lung cancer and in patients with neuroblastoma, in whom NSE is used as a serum tumor marker. We have investigated 32 patients with histologically proven medullary thyroid carcinoma, a tumor of neuroendocrine origin, in which the classical tumor marker calcitonin (CT) was pathologically elevated. Positive immunocytochemistry for NSE and CT in C-cells was obtained in all cases. Increased serum NSE levels were found in only 5 of 32 patients, there was no correlation between NSE and CT concentrations. We also compared NSE and CT serum levels during long-term follow-up and again found no correlation between NSE and CT. After i.v. stimulation tests with pentagastrin and calcium, no correlation was found between NSE and CT serum levels. We conclude, therefore, that in medullary thyroid carcinoma NSE is useful for immunocytochemistry but not a reliable serum tumor marker.

Calcitonin↗

Action of calcitonin gene-related peptide at the calcitonin receptor of the T47D cell line.

Some effects of calcitonin (CT) can also be produced by calcitonin gene-related peptide (CGRP), an alternative product of the calcitonin gene. This might be mediated by interaction of CGRP at the CT-receptor site. The human breast cancer cell line T47D possesses well characterized CT-receptors (KD = 2.3 x 10(-10) M for 125I salmon CT). 50% inhibition of 125I-sCT binding was achieved with 10(-9) M sCT, 5 x 10(-6) M rat CGRP and 10(-5) M human CGRP. Half maximal cAMP production in T47D cells was seen with 6 x 10(-10) M sCT, 5 x 10(-6) M rCGRP and 10(-5) M hCGRP. Binding and displacement capacity as well as the biological activity of CT and CGRP seems to correlate well. These findings suggest that CGRP in pharmacological doses acts via the CT-receptor. This could be explained by the homology and conformational similarities between CT and CGRP.

Breast Neoplasms↗

Synaptophysin identified in metastases of neuroendocrine tumors by immunocytochemistry and immunoblotting.

Synaptophysin, an Mr 38,000 integral membrane glycoprotein of neurotransmitter vesicles, has been identified in diverse primary neuroendocrine (NE) tumors of both neural and epithelial origin (Wiedenmann and co-workers, Proc Natl Acad Sci USA 1986; 83: 3500-3504). In the present study, metastases of several types of NE tumors, including medullary thyroid carcinoma, gastrinoma, insulinoma, small (oat) cell carcinoma of the lung, gastrointestinal carcinoid, and neuroblastoma, were examined for the presence of synaptophysin by immunocytochemistry, with the use of tissue sections as well as centrifuged cell suspensions and by immunoblotting of tumor proteins. The results show that expression of synaptophysin can be maintained during formation of metastases. Therefore, the authors propose that synaptophysin antibodies be used for the positive identification of metastatic NE tumors, notably in differential diagnosis. The possible implications of these findings for tumor diagnosis are discussed.

Endocrine System Diseases↗