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Biomedical subjects

A J Van Herle

Publications and source records attributed to A J Van Herle.

At least 19 recordsLinked to original sources
PubMed2001

Troglitazone inhibits growth of MCF-7 breast carcinoma cells by targeting G1 cell cycle regulators.

Peroxisome proliferator activated receptor gamma (PPARgamma) is a member of the nuclear receptor superfamily. Ligand activation of PPARgamma has been shown to cause growth arrest in several human tumor cell types, but the underlying molecular mechanism has not been elucidated. We report here that the PPARgamma ligand troglitazone (TRO) inhibited MCF-7 cell proliferation by blocking events critical for G1 --> S progression. Flow cytometry demonstrated that TRO at 20 microM increased the percentage of cells in G1 from 51 to 69% after 24 h. Accumulation of cells in G1 was accompanied by an attenuation of Rb protein phosphorylation associated with decreased CDK4 and CDK2 activities. Inhibition of CDK activity by TRO correlates with decreased protein levels for several G1 regulators of Rb phosphorylation (cyclin D1, and CDKs 2, 4, and 6). Overexpression of cyclin D1 partially rescued MCF-7 cells from TRO-mediated G1 arrest. Targeting of G1 regulatory proteins, particularly cyclin D1, and the resulting induction of G1 arrest by TRO may provide a novel antiproliferative therapy for human breast cancer.

Annexin A5↗
PubMed2001

Long-term management and outcome of parathyroidectomy for sporadic primary multiple-gland disease.

HYPOTHESIS: For a specific subset of patients with sporadic primary multiple-gland parathyroid disease, subtotal parathyroidectomy results in long-term normocalcemia in the majority of patients, with a minimal complication rate. DESIGN: Retrospective analysis of outcomes in patients undergoing parathyroidectomy performed by a single surgeon (A.E.G.) between 1984 and 1999. SETTING: A multidisciplinary endocrine service based at a tertiary referral center. PATIENTS: Patients undergoing subtotal parathyroidectomy for primary hyperparathyroidism due to sporadic multiple-gland disease identified from a single surgeon's operative records (A.E.G.). MAIN OUTCOME MEASURES: Data analyzed included demographic factors, operative and pathologic findings, and postoperative and long-term clinical and laboratory results, including calcium and intact parathyroid hormone levels. RESULTS: Of 379 patients undergoing parathyroidectomy for hyperparathyroidism between 1984 and 1999, 49 (13%) had sporadic multiple-gland disease. Median preoperative calcium and intact parathyroid hormone (iPTH) levels were 2.7 mmol/L (10.8 mg/dL) and 11.79 pmol/L, respectively. Postoperative calcium and iPTH levels were available in 39 patients, and median values were 2.28 mmol/L (9.1 mg/dL) and 2.84 pmol/L, respectively. Long-term follow-up was available for 36 patients (73%), and duration ranged from 6 to 180 months (median, 44 months). Median calcium and iPTH levels at follow-up were 2.3 mmol/L (9.2 mg/dL) and 3.26 pmol/L, respectively, with 3 (8%) of 36 patients having evidence of persistent or recurrent hyperparathyroidism. No patient had biochemical evidence of hypoparathyroidism at long-term follow-up. Five patients (14%) had persistent elevated iPTH levels (range, 8.11-10.95 pmol/L) and normal calcium levels. CONCLUSIONS: Subtotal parathyroidectomy for sporadic primary multiple-gland disease resulted in a long-term normocalcemia rate of 92%, with minimal complications. Selective subtotal parathyroidectomy can yield excellent long-term results in patients with multiple-gland disease.

Adult↗
PubMed2000

Amyloid goiter in a case of systemic amyloidosis secondary to ankylosing spondylitis.

Infiltrative diseases of the thyroid include systemic sclerosis, hemochromatosis, sarcoidosis, chondrocalcinosis and amyloidosis. Only rarely does thyroid amyloidosis result in clinically palpable goiter. Classically, amyloidosis is associated with tuberculosis, rheumatoid arthritis, multiple myeloma or inflammatory bowel disease. Only rarely does clinical amyloidosis develop in the setting of ankylosing spondylitis. We describe a case of amyloid goiter in a patient with ankylosing spondylitis-associated amyloidosis.

Adult↗
PubMed2000

Thyrotoxicosis in a male patient associated with excess human chorionic gonadotropin production by germ cell tumor.

We report a case of a man with thyrotoxicosis due to excess production of human chorionic gonadotropin (hCG) by metastatic choriocarcinoma, followed by alterations of his thyroid function tests by nonthyroidal illness. All reported cases of thyrotoxicosis due to high hCG levels in male patients are reviewed. Patients with this syndrome usually have widespread choriocarcinoma and relatively few symptoms of thyrotoxicosis. Typically, if the patient survives the metastatic germ cell tumor, the thyrotoxicosis resolves as the hCG levels decrease after chemotherapy directed at the choriocarcinoma. Only rarely are specific antithyroid medications required. The hCG molecule directly stimulates the thyroid gland, and these patients appear to have in the serum a predominance of acidic variants of hCG with greater intrinsic thyroid-stimulating activity than the hCG secreted during a normal pregnancy. In general, these patients have a poor prognosis due to the usually widespread nature of the germ cell tumor at the time of diagnosis.

Adult↗
PubMed1999

Growth inhibitory effects of flavonoids in human thyroid cancer cell lines.

Previous studies have indicated that flavonoids exhibit antiproliferative properties on some hormone-dependent cancer cell lines, such as breast and prostate cancer. In the present study, the effects of some selected flavonoids, genistein, apigenin, luteolin, chrysin, kaempferol, and biochanin A on human thyroid carcinoma cell lines, UCLA NPA-87-1 (NPA) (papillary carcinoma), UCLA RO-82W-1 (WRO) (follicular carcinoma), and UCLA RO-81A-1 (ARO) (anaplastic carcinoma) have been examined. Among the flavonoids tested, apigenin and luteolin are the most potent inhibitors of these cell lines with IC50 (concentration at which cell proliferation was inhibited by 50%) values ranging from 21.7 microM to 32.1 microM. The cells were viable at these concentrations. Using NPA cells known to be estrogen receptor positive (ER+), it was shown that no significant [3H]-E2 displacement occurred with these flavonoids at the IC50 concentration. In WRO cells that are known to have an antiestrogen binding site (AEBS), biochanin A caused a stronger inhibitory growth effect (IC50 = 64.1 microM) than in NPA and ARO cells. In addition, it was observed that biochanin A has an appreciable binding affinity for the AEBS as indicated by the displacement of [3H]-tamoxifen from the WRO cells. In summary, flavonoids have potent antiproliferative activity in vitro against various human thyroid cancer cell lines. The inhibitory activity of certain flavonoid compounds may be mediated via the AEBS and/or type II EBS. The observation that ARO cells that lack both the AEBS and the ER are effectively inhibited by apigenin and luteolin suggest that other mechanisms of action are operative as well. The present study suggests that flavonoids may represent a new class of therapeutic agents in the management of thyroid cancer.

Adenocarcinoma, Follicular↗
PubMed1999

Unilateral adrenal medullary hyperplasia: another form of curable hypertension?

A case of unilateral adrenal medullary hyperplasia is presented in a 49-year-old caucasian female without multiple endocrine neoplasia association. The patient presented with episodic hypertension and paroxysms suggesting an underlying phaeochromocytoma. Biochemical supported this diagnosis but no discrete tumour was found on preoperative localising studies or at the time of surgery. The patient underwent a unilateral adrenalectomy with confirming adrenal medullary hyperplasia with complete resolution of her symptoms for six months.

Adrenal Hyperplasia, Congenital↗
PubMed1998

Sentinel lymphadenectomy in thyroid malignant neoplasms.

BACKGROUND: Lymph node metastases for well-differentiated thyroid cancer are associated with high recurrence rates. Surgical options consist of blind nodal sampling, "berry-picking" procedures, and modified radical neck dissections. Sentinel lymph node dissection (SLND) has been described by our institution for melanoma and breast cancer. We have investigated the feasibility of SLND for thyroid cancer. DESIGN: From August 1994 to October 1996 we investigated the technique of intraoperative lymphatic mapping and SLND in 17 patients undergoing surgical management of a suspicious thyroid nodule not accompanied by palpable cervical adenopathy. SETTING: Patients were referred from endocrinologists in community and academic practices. Procedures were performed in a community hospital. PATIENTS: There were 14 women and 3 men, ranging in age from 22 to 69 years (median, 48 years). INTERVENTIONS: At surgery, we exposed the thyroid lobe and used a tuberculin syringe to inject 0.1 to 0.8 mL of 1.0% isosulfan blue dye (mean, 0.5 mL) directly into the thyroid mass. Within seconds the blue dye passed along the lymphatics to the sentinel lymph node, which was then excised. Nodes were examined by routine processing and keratin immunohistochemical analysis to detect micrometastasis. MAIN OUTCOME MEASURES: The feasibility of lymphatic mapping in determining primary drainage of suspicious thyroid nodules. RESULTS: Lymphatic mapping and SLND was followed by total thyroidectomy, except in 1 patient who underwent lobectomy for benign disease. Of the 17 nodules, 12 were ultimately diagnosed as thyroid carcinoma, 3 were follicular adenomas, and 2 were colloid nodules. Tumor sizes ranged from 0.8 to 4.0 cm. Lymphatic mapping was unsuccessful in 2 patients, whose lymphatics mapped to the retrosternum. All of the sentinel lymph nodes were paratracheal except in 2 women who also had jugular nodes that stained blue. Five (42%) of the 12 tumor nodules were associated with positive sentinel lymph nodes. Central neck dissections were performed in 5 patients; in 2 instances (17%), the sentinel node was the only tumor-bearing lymph node. CONCLUSIONS: This is the first report of SLND for thyroid carcinoma. Our preliminary findings indicate that SLND can detect nonpalpable nodal metastasis with the same ease as in melanoma and breast cancer. The clinical significance of this technique in thyroid cancer remains to be determined.

Adult↗
PubMed1998

Paper chromatography prior to cortisol RIA allows for accurate use of the dexamethasone suppression test in chronic renal failure.

The assessment of the hypothalamic-pituitary-adrenal axis in patients with chronic renal failure (CRF) on hemodialysis is often hampered by abnormal responses to the standard 1-mg dexamethasone suppression test. Various mechanisms have been proposed to explain this lack of suppressibility. The present study was designed to look into the mechanisms possible for these findings in patients with CRF. We studied 6 patients with CRF on hemodialysis and 5 healthy subjects utilizing the 1-mg dexamethasone suppression test as well as the 50-mg hydrocortisone suppression test. Samples were assayed for dexamethasone, adrenocorticotropic hormone, corticosterone, and cortisol by both direct radioimmunoassay (RIA) and RIA after paper chromatography. Utilizing the direct cortisol RIA, 4 of 6 patients with CRF exhibited blunted dexamethasone suppression, while all 6 patients showed normal suppressibility after dexamethasone when cortisol was measured after paper chromatography. In contrast, all controls showed normal suppressibility regardless of the cortisol assay procedure used. The hydrocortisone suppression test was unreliable in the setting of CRF. Mean dexamethasone levels were similar in both groups. Plasma adrenocorticotropic hormone levels were significantly higher in the CRF patients, possibly indicative of an underlying hypothalamic-pituitary-adrenal axis abnormality. Abnormalities in dexamethasone suppression testing in patients with CRF may be explained by the overestimation of cortisol levels by direct RIA rather than by alteration of dexamethasone absorption or metabolism. Measurement of cortisol after paper chromatography is superior to direct RIA of cortisol in patients with CRF.

Adrenocorticotropic Hormone↗
PubMed1998

Calcium-sensing by parathyroid glands in secondary hyperparathyroidism.

Calcium-sensing by the parathyroids is abnormal in familial benign hypocalciuric hypercalcemia and in primary hyperparathyroidism (primary HPT), but the role of a calcium-sensing defect in uremic secondary hyperparathyroidism (secondary HPT) remains controversial. To study the regulation of PTH release by calcium, set point estimates were obtained using the four parameter model during in vivo dynamic tests of parathyroid gland function in 31 patients with secondary HPT, 8 patients with advanced secondary HPT studied shortly before undergoing parathyroidectomy (Pre-PTX), 3 patients with primary HPT, and 20 subjects with normal renal function (NL); the response to 2-h i.v. calcium infusions was also evaluated. Neither blood ionized calcium (iCa+2) levels nor the set point for calcium-regulated PTH release differed between secondary HPT and NL; iCa+2 levels and set point values were moderately elevated in Pre-PTX and markedly elevated in primary HPT. Compared with values obtained in NL, the lowest serum PTH levels achieved during calcium infusions, expressed as a percentage of pre-infusion values, were incrementally greater in secondary HPT, Pre-PTX, and primary HPT, whereas the slope of the relationship between iCa+2 and PTH, expressed as the natural logarithm (ln) of percent preinfusion values, decreased incrementally in secondary HPT, Pre-PTX, and primary HPT. The inhibitory effect of calcium on PTH release is blunted both in secondary HPT and primary HPT because of increases in parathyroid gland mass, but a calcium-sensing defect is a late, rather than early, consequence of renal secondary HPT.

Adolescent↗
PubMed1996

Differences in PTH (1-84) release in response to ambient calcium concentrations of parathyroid adenoma fragments and dispersed parathyroid adenoma cells in culture.

In a previous study we observed that during perfusion of normal human parathyroid tissue, the release of PTH (1-84) was modulated by ambient extracellular calcium (Ca++) and lithium (Li+) concentrations in the media and preliminary studies indicated that this stimulus-response coupling was absent in human parathyroid adenoma fragments. The present study compares the responsiveness of parathyroid adenoma fragments and isolated parathyroid adenoma cells from the same adenoma and their response to Ca++ changes and Li+ presence in culture media. The data indicate that parathyroid adenoma tissue fragments fail to respond to ambient changes in Ca++ and Li+. In contrast, dispersed parathyroid cells preparations responded with a significant increase of PTH (1-84) release (50%) under the influence of low ambient calcium concentrations. Six of the dispersed cell preparations also responded with a 45% decrease in PTH release under the influence of a high Ca concentration in the medium. Isolated parathyroid cells obtained from the same adenoma's did not respond to the presence of Li++ in the medium. These data suggest tat human parathyroid adenoma tissue functions autonomously and is not sensitive to calcium regulation in the tissue configuration as opposed to the isolated cell suspensions. The nature of this difference remains elusive.

Adenoma↗
PubMed1996

Human thyroglobulin reference material (CRM 457). 1st Part: Assessment of homogeneity, stability and immunoreactivity.

This paper describes the assessment of the homogeneity and stability of a purified and lyophilized human thyroglobulin (Tg), and characterizes its immunoreactivity. The purified and lyophilized Tg is intended to be used as a primary reference material to establish calibration of working serum based reference material. The programme involved the participation of 15 European laboratories and one laboratory from the United States. The homogeneity of the content of the ampoules was considered acceptable (< 9%). The stability was tested by accelerated temperature degradation showing predicted annual relative losses of 0.01% at -70 degrees C and 1.04% at -20 degrees C. The immunoreactivity of the Tg material as measured in different laboratories varied mostly according to the method used rather than the laboratory. The interlaboratory variability showed that the two commercial methods used in several laboratories (kit 1 and 2) had an interlaboratory variation (CV) of 15.9% (N = 5) and 7.1% (N = 3), respectively, whereas the total interlaboratory CV was 64.3% (N = 18). The immunoreactive Tg had dilution curves parallel with other Tg calibrators (those of the methods). Dilution curves of the Tg material after storage at various temperatures and time were parallel in both RIA and IRMA. In conclusion, we have prepared a Tg reference material which in extensive studies in several participating laboratories has demonstrated a sufficient homogeneity and stability as well as dilution curves parallel to the calibrators of all the immunoassays tested in the study. This reference material is considered the first step towards decreasing the interlaboratory variability between Tg immunoassays.

Drug Stability↗
PubMed1996

Human thyroglobulin reference material (CRM 457). 2nd Part: Physicochemical characterization and certification.

This report describes the characterization of a purified human thyroglobulin (Tg) reference material, and details the procedures used in its certification. The purified Tg is intended to be used as a primary reference material to establish calibration of working serum based reference material for immunoassay procedures. The programme involved the participation of 15 European laboratories and one laboratory from the United States. The physicochemical characterization showed by polyacrylamide gel electrophoresis and immunoblotting that the purified Tg had for the major part the expected molecular size of 660 kDa with traces of lower molecular forms. The amino acid composition was close to that demonstrated for the cDNA and the content of iodine was in keeping with a moderately to highly iodinated Tg. The mass concentration in reference material RM 457 is certified to be (0.324 +/- 0.018) g/L on the basis of protein determined by the Lowry method and supported by nitrogen determination, absorbance measurement, and amino acid analysis. This reference material is considered the first step towards decreasing the interlaboratory variability between Tg methods of measurement.

Amino Acids↗
PubMed1993

Presence of a specific antiestrogen binding site on human follicular thyroid carcinoma cell line (UCLA RO 82 W-1): inhibition by an endogenous ligand present in human serum.

A receptor for antiestrogens, distinct from the estrogen receptor, has been identified in several tissues including the MCF-7 breast cancer cell line. Estrogen receptors have also been found in normal and pathological thyroid tissue homogenates. We demonstrate the presence of an antiestrogen binding site (AEBS) on a pure human follicular thyroid carcinoma cell line (UCLA RO 82 W-1) using a 3H-tamoxifen (3H-TAM) binding assay. The binding of 3H-TAM to the AEBS was determined after preincubation (30 min) of the cells with excess 17 beta-estradiol (2 mumol/L). Specific and saturable binding of 3H-TAM to the cells was observed. Displacement of the tracer from its binding site was dose dependent. Scatchard analysis revealed a dissociation constant (Kd) of 73 nmol/L, indicating a binding site with moderate affinity and capacity (72 pmol/10(6) cells). Using this assay we were also able to demonstrate the presence of an endogenous ligand for the AEBS in ethanol extracts of human serum. Cell growth and 3H-thymidine incorporation by the follicular thyroid carcinoma cells were inhibited when the cells were exposed to TAM (1.5 mumol/L). In conclusion, TAM is able to bind to a specific receptor on this follicular thyroid carcinoma cell line, and a natural circulating ligand present in ethanol extracts of human serum interferes with its binding.

Adenocarcinoma, Follicular↗
PubMed1991

Immunodetection of thyroid tumors: role of immuno aggregates.

To understand the inconsistent immunodetection of tumors in vivo, a labelled monoclonal antibody (MAb) against a human follicular cancer cell line (UCLA RO 82 W-1) was used as a model for in vitro and in vivo studies. The 131I labelled MAb x RO 82 W-1 bound to its target cells (10% to 70%) mainly because of the generation of immunoglobulin aggregates. Aggregates generated by the freezing process were shown by polyacrylamide gel electrophoresis (PAGE) and their removal by filtration. When the aggregated 131I MAb x RO 82 W-1 was injected into BALB/c mice bearing UCLA RO 82 W-1 tumors, a high tumor/blood ratio was found in the large tumors. The tracer concentrated in the macroscopically visible necrotic part of the tumor was largely responsible for the scintigraphic detection. Irrelevant 131I-IgG also concentrated in necrotic regions of tumors. Scintigraphic detection of thyroid tumors in this model was related to the degree to which labeled aggregates of IgG, regardless of their specificity, localized in necrotic regions of the tumors.

Animals↗
PubMed1991

Endocardial metastases of follicular thyroid carcinoma: a case report and review of the literature.

An 87-year-old woman with follicular carcinoma of the thyroid gland is described, who developed ventricular tachycardia (VT) with loss of consciousness. The patient had developed widespread metastatic follicular carcinoma and succumbed to her disease. At autopsy, intracardiac metastases were found and were documented to be of thyroidal origin by the presence of thyroglobulin, using immunohistological staining techniques, using a specific antithyroglobulin antibody.

Adenocarcinoma↗
PubMed1990

Thyroid dysfunction in a prospectively followed series of patients with progressive systemic sclerosis.

Thirty-nine patients with progressive systemic sclerosis (PSS) in stable clinical conditions were extensively evaluated for the presence of thyroid disease. Two patients had previously undetected hypothyroidism while 7 additional patients had normal serum thyroid hormone levels but an exaggerated TSH response to thyrotropin-releasing hormone (TRH) administration, consistent with subclinical hypothyroidism. Four of the 9 subjects with abnormal TRH responses had positive antithyroid antibodies and of the remaining 5, 4 had been on chlorambucil or prednisone. Basal TSH and TSH response to TRH were significantly higher in PSS patients as a group when compared to a control group and increased with increasing duration of PSS. Serum antithyroid antibodies (antithyroglobulin and/or antimicrosomal antibodies) were positive in 18% and thyroid scans were abnormal in 18% of the patients. The euthyroid sick syndrome was not seen. Our findings indicate an increased frequency of, sometimes previously unsuspected, clinical and subclinical hypothyroidism in stable PSS patients which appears to be autoimmune in nature and becomes more prevalent with increased PSS duration. Careful and regular monitoring of the thyroid function in PSS patients is advisable.

Adult↗
PubMed1990

Effects of 13 cis-retinoic acid on growth and differentiation of human follicular carcinoma cells (UCLA R0 82 W-1) in vitro.

Dedifferentiation of human thyroid tumors is frequently found in humans. The effect of retinoids (13 cis-RA) was studied on the proliferation and differentiation of a human follicular cell line in vitro (UCLA R0 82 W-1). A significant and dose-dependent reduction (P less than 0.001) in cell number and [3H] thymidine uptake was found in cells exposed to 13 cis-RA up to 10 microM. Higher concentrations of 13 cis-RA, however, led to a dose-dependent restoration of cell proliferation. Various parameters of differentiation increased under the influence of 13 cis-RA (10 microM) over nonexposed cells. The 125I uptake increased 4-fold over that in control nonexposed cells (P less than 0.05). [125I] Epidermal growth factor binding increased 5-fold, and [125I] human TSH binding increased significantly after exposure to 13 cis-RA (P less than 0.02). Deiodinase activity, however, was significantly lower in 13 cis-RA exposed cells than in control cells. The present study shows that 13 cis-RA (10 microM) drives the tumor cells toward a more normal state of proliferation and differentiation.

Adenocarcinoma↗