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Biomedical subjects

A Grauer

Publications and source records attributed to A Grauer.

46 records · Page 3Linked to original sources
PubMed1992

PDN-21 (katacalcin) and chromogranin A: tumor markers for medullary thyroid carcinoma.

The malignant C-cell releases several markers of potential clinical significance into the circulation. To determine the usefulness of these markers for management of medullary thyroid carcinoma (MTC), it is necessary to compare the usefulness of these markers with calcitonin (CT), the classical tumor marker for MTC. Measurement of serum concentrations of the peptide PDN-21 (katacalcin), a carboxyterminal cleavage product of procalcitonin, showed a high correlation with serum CT levels (r = 0.99, P < 0.01, n = 65 patients with MTC). The presence of equimolar concentrations of CT and PDN-21 (CT/PDN-21 molar ratio = 0.95 +/- 0.33) indicates the peptide is cosecreted with CT. Stimulation of CT release by intravenous pentagastrin was associated with a parallel increase of PDN-21, providing further evidence of cosecretion of these two peptides. Finally, measurement of either PDN-21 or CT in selective venous catheterization specimens was useful for localization of MTC. Chromogranin A (CgA) levels were also measured in patients with MTC. Circulating levels were elevated in most patients with advanced disease. There was a moderate correlation between CgA and CT serum levels (r = 0.87, P < 0.01, n = 61 patients with MTC). Pentagastrin did not stimulate CgA, and the long half-life of CgA in the circulation did not make it possible to use this peptide for tumor localization by selective venous catheterization. We conclude that measurement of PDN-21 provides an independent assay system for diagnosis, localization, and postoperative management of MTC, whereas CgA measurement is not useful in early diagnosis of MTC and is of limited value for localization or management of progressive disease.

Biomarkers, Tumor↗
PubMed1991

[Therapy of Paget's disease with bisphosphonate pamidronate (AHPrBP, formerly APD)].

We studied the effect of the intravenous administration of the bisphosphonate pamidronate (AHPrBP) in 7 patients with Paget's bone disease. The medication was given in a daily dose of 20 mg for 9 days in 0.9% saline infusion over 4 hours (total dose 180 mg). Thereafter the patients received no therapy. At the end of treatment a slight but significant fall of plasma calcium (p less than or equal to 0.01) was observed, but no patient displayed hypocalcemia. The urinary excretion of hydroxyproline fell below 45% of initial within 6 days of treatment. Only 3 out of 7 patients showed a decline in alkaline phosphatase activity (AP) already at the end of treatment, but after 3 to 6 months AP was below 30% of the initial value in all observed patients. After 9 months no relapse of AP was observed. Roentgenograms demonstrated dramatic improvement of bone lesions in one case. Hyperthermia occurred in 2 patients as side effect; one patient developed headache. However, treatment could be continued in all cases. The short-term intravenous administration of pamidronate is a useful means to suppress the activity of Paget's disease and no further treatment is necessary at least for several months.

Aged↗
PubMed1991

Effects of 17 beta-estradiol on calcitonin secretion and content in a human medullary thyroid carcinoma cell line.

The presence of a direct estrogen effect on calcitonin secretion is controversial. Because most of the data available were obtained from complex in vivo systems, we chose an in vitro approach to assess the problem. Using a human C cell carcinoma cell line (TT cells) with well-documented estrogen receptors, we investigated the effect of 17 beta-estradiol (E2) on basal and stimulated calcitonin secretion, on calcitonin content, and on total cellular protein. After short (30 and 180 minutes) and long-term (24 h to 6 days) incubation of the cells with different concentrations of E2 (from 0.01 to 100 nM) we observed no stimulatory but a transient dose-dependent inhibitory effect on CT secretion and content. The nadir of the effect on CT secretion appeared at 24 h, demonstrating a reduction to 80.5 +/- 7.8% of control at 1 nM and to 59.1 +/- 15% of control at 100 nM E2. After 72 h, the CT levels of the E2-exposed groups returned to control levels. The acute stimulation of the cells with TPA plus forskolin after preincubation with E2 up to 6 days showed no difference in the increment of CT release compared to the control groups. Additionally, E2 had a dose-dependent stimulatory effect on cell protein content. The data demonstrate the absence of a direct stimulatory effect of E2 on CT secretion, revealing a dose-dependent inhibitory effect on CT secretion and content.

Calcitonin↗
PubMed1990

1,25-Dihydroxyvitamin D3 suppresses dexamethasone effects on calcitonin secretion.

1,25-Dihydroxyvitamin D3 (1,25(OH)2D3) and dexamethasone (DEX) influence synthesis and secretion of various hormones. Recent reports concerning the interaction of the two steroids revealed opposite--agonistic as well as antagonistic--effects in different biological systems. As calcitonin (CT) gene expression is affected by both agents, inhibited by 1,25(OH)2D3 and stimulated by DEX, we utilized CT secretion and storage as a model to study the combined effects of the two hormones. A human C cell carcinoma cell line (TT) was used, incubating the cells for a period of 4 days with 1,25(OH)2D3 and DEX alone and in combination. 1,25(OH)2D3 resulted in a decrease, whereas DEX resulted in a increase of CT secretion and content. Combining the two steroids, 1,25(OH)2D3 surprisingly abolished the stimulation of DEX on CT secretion and content. The underlying mechanism is yet unclear and could be envisioned to include steroid receptor regulation or gene transcription.

Animals↗
PubMed1990

In vitro detection of neutralizing antibodies after treatment of Paget's disease of bone with nasal salmon calcitonin.

To elucidate the biologic relevance of circulating sCT antibodies, an in vitro bioassay system for the detection of neutralizing antibodies was developed utilizing the human breast carcinoma cell line T47D. We reasoned that the inhibition of the dose-dependent cAMP response to sCT in the T47D assay system by anti-sCT antibodies could be used to determine the in vivo relevance of these antibodies. In this report the clinical course of nine patients with Paget's disease of bone treated with intranasal sCT was correlated with the presence of 125I-sCT binding and neutralizing antibodies. Of these seven patients, four were found to have neutralizing antibodies; the appearance of the antibodies coincided with the development of resistance. One of these patients was subsequently treated with human calcitonin and revealed a good response to the treatment. There was no clinical resistance observed in the three patients with 125I-sCT binding antibodies but no neutralizing antibodies; no resistance was observed in two patients without 125I-sCT binding or neutralizing antibodies. We conclude that this new technique to determine the biologic relevance of circulating anti-sCT antibodies may be an useful adjunct for determining the cause of resistance in patients treated with sCT.

Administration, Intranasal↗
PubMed1990

Changing concepts in the management of hereditary and sporadic medullary thyroid carcinoma.

Recent linkage of the gene for multiple endocrine neoplasia type 2A and 2B to the centromeric region of chromosome 10 has provided new insight into the causes of medullary thyroid carcinoma and has provided tools to diagnose gene carriers status for this syndrome with greater than 90% certainty. This review focuses on how these advances influence the clinical management of both sporadic and hereditary medullary thyroid carcinoma and discusses how tests based on the genetic linkage studies will aid in the early diagnosis and treatment of this syndrome. In addition, the authors have focused on several controversial management questions regarding the type and extent of surgery for this thyroid tumor, the management of the patient with metastatic disease, and the approach to management of other manifestations of multiple endocrine neoplasia types 2A and 2B. This review attempts to provide a balanced overview of these complex issues.

Adrenal Gland Neoplasms↗
PubMed1989

Role of voltage-dependent calcium channels in secretion of calcitonin from human medullary thyroid carcinoma cells.

Extracellular calcium concentration is an important regulator of calcitonin secretion. We used primary cell cultures of human medullary thyroid carcinoma to study the role of voltage dependent calcium channels for stimulus secretion coupling. Increasing extracellular calcium concentration (1.6-5.0 mM) in the medium caused a dose dependent release of calcitonin. The calcium channel activator BAY K 8644, a dihydropyridine, stimulated calcitonin secretion in a dose dependent manner (10(-7)-10(-5) M). This effect was completely inhibited by equimolar concentrations of the calcium channel blocker nifedipine and abolished in the absence of extracellular calcium. Similarly, nifedipine suppressed the stimulatory action of extracellular calcium. The effects of calcium and BAY K 8644 with and without nifedipine suggest that calcium influx via voltage dependent calcium channels plays an important role in calcitonin secretion. The primary cell culture of human medullary thyroid carcinoma is a good model for the study of stimulus secretion coupling.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1987

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↗
PubMedDate not supplied

Calcium, vitamin D and etidronate for the prevention and treatment of corticosteroid-induced osteoporosis in patients with rheumatic diseases.

INTRODUCTION: Long-term glucocorticoid therapy, a major risk factor for the development of osteoporosis, is often necessary in chronically ill patients. At present there are no generally accepted guidelines for the prevention or treatment of steroid-induced osteoporosis. METHODS: In an open prospective study we investigated 99 patients with chronic rheumatic diseases receiving > or = 5 mg/day of prednisolone or the equivalent for at least one year. The objective was to identify osteoporosis risk factors in addition to glucocorticoid therapy and to evaluate the efficacy of prevention with calcium/vitamin D (group 1--patients with osteopenia) and treatment with cyclical etidronate (group 2--patients with osteoporosis). Biochemical markers of bone turnover, clinical parameters and bone mineral density (BMD) were measured. RESULTS: Increasing age and postmenopausal status were associated with more advanced manifestations of steroid-induced osteoporosis (p < 0.05). One year after the start of therapy parameters of bone metabolism increased significantly in group 1, while BMD did not change. In group 2, lumbar spine BMD increased significantly (p < 0.05) whereas femoral neck BMD and bone metabolism parameters remained constant. The intensity of back pain decreased in both groups (p < 0.05). There were fewer new fractures in group 2 than in group 1. CONCLUSION: Treatment with etidronate is effective in patients with glucocorticoid-induced osteoporosis.

Adult↗