1/27. adrenal insufficiency after incomplete resection of pituitary macrocorticotropinoma of Cushing's disease: role of high molecular weight ACTH.A 15-year-old girl with Cushing's disease exhibited adrenal insufficiency following incomplete trans-sphenoidal resection of a large pituitary corticotropinoma, approximately 35 mm in diameter. Within two weeks following surgery, her plasma ACTH level decreased from 42 to 13 pmol/l, while, her plasma cortisol levels and urinary excretion of free cortisol decreased from 607 nmol/l and 1112 nmol/day to 94 nmol/l and 55 nmol/day, respectively. Immunoreactive ACTH was characterized in plasma using Sephadex G-75 column chromatography and measuring ACTH with immunoradiometric assay (IRMA) and radioimmunoassay (RIA) to determine additional peaks, other than the one demonstrated for 1-39 ACTH. In particular, when measured with RIA, a broad peak including the high molecular weight ACTH was detected as well as 1-39 ACTH. The bioactivity of the high molecular weight ACTH in patient plasma was lower than the reference range of 1-39 ACTH, which is determined by the ability of dispersed rat adrenocortical cells to secrete corticosterone. The large pituitary corticotropinoma found in this patient secreted not only 1-39 ACTH but also high molecular weight proopiomelanocortin (POMC)-derived peptides, which could be detected by measuring with IRMA and RIA for ACTH. Based on the results of biological activity and molecular ratios, no positive evidence could be found to support the hypothesis that the high molecular weight ACTH induced any postoperative adrenal insufficiency in this patient. However, based on this study, the possibility of adrenal insufficiency should be carefully monitored, even when post-operative remnant tumor tissue is clearly present in patients with Cushing's disease, accompanied by macrocorticotropinoma.- - - - - - - - - - ranking = 1keywords = chromatography (Clic here for more details about this article) |
2/27. Significant gene expression of insulin-like growth factor ii and proliferating cell nuclear antigen in a rapidly growing recurrent pituitary acth-secreting adenoma.BACKGROUND: We quantified the expression of various growth-related factors in an adrenocorticotropic hormone (ACTH)-secreting adenoma that had recurred very rapidly as invasive macroadenoma. methods/RESULTS: A 43-year-old woman underwent successful transsphenoidal surgery for Cushing's disease. Seven years later, she was admitted to our ward for further endocrine examinations. In spite of a very high plasma ACTH level, the serum cortisol level was normal. Discrepancies between ACTH and cortisol levels were detected on the basis of diurnal rhythms, dexamethasone suppression tests, and corticotropin-releasing hormone test. The patient showed no clinical features of Cushing's disease. magnetic resonance imaging of the pituitary showed an almost empty sella, and no microadenoma was found. These results, along with those of Sephadex column gel filtration and high-performance liquid chromatography of plasma-immunoreactive ACTH, suggested that the patient's residual corticotrophs secreted biologically inactive ACTH. Two years later, the patient suddenly developed diplopia and right abducens nerve palsy. She was slightly moonfaced and centrally obese. Her plasma ACTH and serum and urinary free cortisol levels were elevated, although discrepancies between ACTH and cortisol still existed. magnetic resonance imaging revealed a large pituitary mass with suprasellar and cavernous sinus extensions. The tumor was excised, and the proopiomelanocortin gene and the expression of growth-related factors were analyzed. No mutations were found in the ACTH-coding region of the proopiomelanocortin gene. A significant expression of insulin-like growth factor II and proliferating cell nuclear antigen mRNAs was demonstrated. A high MIB-1 antibody labeling index was also detected in the adenoma tissue, suggesting high Ki-67 expression. CONCLUSION: These growth- and proliferation-related factors might be involved in the rapid growth and aggressiveness of this patient's pituitary adenoma.- - - - - - - - - - ranking = 1keywords = chromatography (Clic here for more details about this article) |
3/27. testosterone-secreting gonadotropin-responsive adrenal adenoma and its treatment with the antiandrogen flutamide.A 55-year-old woman with virilization had an appreciably elevated testosterone level, which was not suppressed by dexamethasone, but was increased by stimulation with human chorionic gonadotropin (hCG). ultrasonography and computed tomography revealed an adenoma 2.5-3.0 cm in diameter in the right adrenal gland. The patient was treated with the antiandrogen flutamide in a daily dose of 500 mg for 4 months. A substantial regression of her hirsutism was observed during flutamide administration, but the serum testosterone level remained high. Right adrenalectomy was performed. Histologically, the tumor proved to be an adrenocortical adenoma of zona reticularis type. The adenoma tissue contained specific hCG receptors (187 fmol/g). The steroid concentration in the tumor tissue was examined by means of high pressure liquid chromatography-radioimmunoassay (HPLC-RIA). A significantly increased testosterone content was detected, and the levels of its precursors, androstenedione and dehydroepiandrosterone, were also elevated. Following adrenalectomy, serum testosterone concentration decreased to the normal level. The mechanism of the inappropriate regulation in the testosterone production of the adrenal tumor has not been fully elucidated.- - - - - - - - - - ranking = 1keywords = chromatography (Clic here for more details about this article) |
4/27. Pitfalls in pituitary diagnosis: peculiarities of three cases.Due to the increasing availability and sensitivity of diagnostic methods, biochemical and imaging abnormalities of pituitary function and anatomy are becoming more frequent. Hyperprolactinaemia was found in three women without any prolactin (PRL) related clinical features. All three patients had normal libido, regular menses with evidence of ovulation, no galactorrhoea, and normal FSH, LH, TSH and free T4 serum levels. magnetic resonance imaging (MRI) of the sellar region showed images that were compatible with pituitary microadenomas in all three cases. Due to the discordance between laboratory and clinical features, we searched for the presence of PRL aggregates with high molecular weight and low biological activity (macroprolactinaemia). Initially, we screened with a polyethylene glycol precipitation method, and then confirmed the presence of macroprolactinaemia by chromatography. All three cases screened positive for the presence of macroprolactinaemia. MRI alterations, compatible with pituitary microadenomas, may be due to true microincidentalomas, normal anatomical variations or imaging artefacts. In conclusion, we have described the presence of double diagnostic pitfalls that might lead to unnecessary medical or surgical intervention.- - - - - - - - - - ranking = 1keywords = chromatography (Clic here for more details about this article) |
5/27. Secretion of high-molecular-weight adrenocorticotropic hormone from a pituitary adenoma in a patient without Cushing stigmata. Case report.The authors report a case in which a patient harbored a corticotroph macroadenoma that secreted biologically inactive high-molecular-weight adrenocorticotropic hormone (ACTH) as well as authentic ACTH 1-39. The secretion of the high-molecular-weight ACTH was determined using gel chromatography. The authors believe that these two molecules competed with each other at the ACTH receptor and, thus, the bioactivity of ACTH 1-39 was masked and Cushing features were not manifested in the patient. This type of silent corticotroph adenoma may be categorized as a clinically nonfunctioning adenoma. Plasmas from patients with silent corticotroph adenomas, which are identified by positive immunohistochemical staining of ACTH, should be frozen, stored, and analyzed using gel chromatography to examine whether the tumors produce and secrete high-molecular-weight ACTH.- - - - - - - - - - ranking = 2keywords = chromatography (Clic here for more details about this article) |
6/27. Overproduction of an amino-terminal form of PTH distinct from human PTH(1-84) in a case of severe primary hyperparathyroidism: influence of medical treatment and surgery.OBJECTIVE: Rare patients with severe primary hyperparathyroidism present with large parathyroid tumours, severe hypercalcaemia, very high PTH levels and osteitis fibrosa cystica. Some of these patients display a large amount of C-PTH fragments in circulation and present with a higher C-PTH/I-PTH ratio than seen in less severe cases of primary hyperparathyroidism. We wanted to determine how PTH levels and circulating PTH high-performance liquid chromatography (HPLC) profiles analysed with PTH assays having different epitopes could be affected by medical and surgical treatment in such patients. DESIGN: A 55-year-old man with severe hypercalcaemia (Ca(2 ): 2.01 mmol/l), very high PTH levels (CA-PTH 82.1 and T-PTH 72 pmol/l) caused by a large parathyroid tumour (7.35 g) and accompanied by significant bone involvement (alkaline phosphatase of 185 UI/l and subperiostal bone resorption of hands) was referred to us. blood was obtained at various time points during his medical treatment, before and after surgery, to measure parameters of calcium and phosphorus metabolism, and of bone turnover. HPLC separations of circulating PTH molecular forms were performed and analysed with PTH assays having 1-4 (CA), 12-18 (T), 26-32 (E) and 65-84 (C) epitopes. RESULTS: Before surgery, serum Ca2 was nearly normalized with hydratation, intravenous (IV) pamidronate and oral vitamin d administration. Despite a decrease in Ca2 to 1.31 mmol/l, CA-PTH and T-PTH levels decreased by half in relation to a threefold increase in basal 1,25-dihydroxyvitamin D [1,25(OH)2D] level (94 to 337 pmol/l). After this initial positive response, hypercalcaemia and elevated CA- and T-PTH levels recurred even if 1,25(OH)2D levels remained elevated. The tumour was removed surgically and proved to be poorly differentiated with nuclear atypia and mitosis. After surgery, the Ca2 level and PTH secretion normalized. The higher CA-PTH level relative to the T-PTH level observed before surgery in this patient was related to the oversecretion of an amino-terminal (N) form of PTH recognized by PTH assays with (1-4) or (26-32) epitopes but not by the T-PTH assay with a (12-18) epitope. This molecular form represented 50% of CA-PTH measured in this patient, but only 7% in less severe cases of primary hyperparathyroidism. It was unaffected by medical therapy and disappeared after surgery. CONCLUSION: The relationship between the overexpression of this N-PTH molecular form and severe primary hyperparathyroidism remains unclear. Further studies will be required in these rare patients to see whether N-PTH is a marker of less well differentiated parathyroid tumours and/or relates to the overproduction of C-PTH fragments in the presence of severe hypercalcaemia.- - - - - - - - - - ranking = 1keywords = chromatography (Clic here for more details about this article) |
7/27. 11 beta-Hydroxydehydroepiandrosterone in a case of virilizing adrenal adenoma: isolation from urine and mitochondrial conversion from dehydroepiandrosterone.11 beta-Hydroxydehydroepiandrosterone has been isolated from the urine of a 14-yr-old girl with a virilizing adrenal adenoma. Its excretion was estimated to be 0.4 mg/24 h by gas chromatography and the compound was further identified by mass spectrometry. When [7-3H]dehydroepiandrosterone was incubated with mitochondria prepared from the adenoma, approximately 10% was converted to 11 beta-hydroxydehydroepiandrosterone. The identity of the radioactive 11 beta-hydroxydehydroepiandrosterone was verified by reversed isotopic dilution, its conversion to 11 beta-hydroxyandrostenedione, and its mobility in several chromatographic systems. This is the first demonstration of an 11 beta-hydroxylase from a human source having an affinity for dehydroepiandrosterone.- - - - - - - - - - ranking = 1keywords = chromatography (Clic here for more details about this article) |
8/27. Lipid-rich cell thyroid adenoma: histopathology with comparative lipid analysis.A second case of the unique lipid-rich cell thyroid adenoma is described complemented by detailed lipid analysis. New observations were made. The cytoplasm of the tumour cells contained scattered, aggregated sudanophil crystals; under polarized light the frozen, unstained sections exhibited numerous birefringent lipid crystals; electron microscopy provided further evidence that the clear cell appearance was due to intracellular lipid droplets with scanty glycogen particles. Comparative lipid analysis by thin layer chromatography and high-pressure liquid chromatography (HPLC) revealed quantitative and qualitative differences in lipid composition of tumour cells when compared with goitre cells from normal thyroid gland and subcutane fat. Qualitative differences in triglyceride composition (by HPLC) between tumour cells and subcutaneous fat indicated that the fat accumulation in the follicle cells was not a result of simple storage, but an expression of altered intracellular lipid metabolism.- - - - - - - - - - ranking = 2keywords = chromatography (Clic here for more details about this article) |
9/27. Studies on the metabolism of steroid hormones in a virilizing adrenal cortex adenoma.Slices of an adreno-cortical adenoma which had been obtained at operation from an 11-year-old girl with clinical signs of virilism were incubated with each of the following steroids: [1,2-3H]progesterone, [4-14C]pregnenolone, [1,2-3H]testosterone, [4-14C]androstenedione and [7-3H]dehydroepiandrosterone, respectively. Isolation and identification of the free radioactive metabolites were achieved by gel column chromatography on Sephadex LH-20, thin-layer chromatography, radio gas chromatography and isotope dilution. After incubation of progesterone, the following metabolites were identified: 11beta-hydroxyprogesterone, 16alpha-hydroxyprogesterone, 17alpha-hydroxyprogesterone, 21-deoxycortisol, corticosterone and cortisol. pregnenolone was metabolized to 17alpha-hydroxypregnenolone, progesterone, dehydroepiandrosterone, androstenedione and 11beta-hydroxyandrostenedione. When testosterone was used as substrate, 11beta-hydroxytestosterone, androstenedione and 11beta-hydroxyandrostenedione were found as metabolites, whereas androstenedione was metabolized to testosterone and 11beta-hydroxyandrostenedione. After incubation of dehydroepiandrosterone, only androstenedione and 11beta-hydroxyandrostenedione were isolated and identified. From these results, it appears that cortisol was formed in the adenoma tissue via 21-deoxycortisol and corticosterone. Delta4-3oxo steroids of the C19-series arose exclusively from pregnenolone via 17alpha-hydroxypregnenolone and dehydroepiandrosterone, and not from progesterone and 17alpha-hydroxyprogesterone. Calculated on the amounts of metabolites formed, the highest enzyme activities were those of the 11beta-hydroxylase and the 17alpha-hydroxylase. It is interesting to note that only traces of testosterone were detected after incubation of androstenedione, whereas testosterone yielded large amounts of androstenedione.- - - - - - - - - - ranking = 3keywords = chromatography (Clic here for more details about this article) |
10/27. Endocrine, biochemical, and morphological studies of a pituitary adenoma secreting growth hormone, thyrotropin (TSH), and alpha-subunit: evidence for secretion of TSH with increased bioactivity.A 40-yr-old man who had acromegaly and hyperthyroidism due to a GH/TSH-secreting pituitary adenoma is described. serum free T4 was 2.8 ng/dl, free T3 was 1.1 ng/dl, and TSH was 1.2-1.5 microU/ml; the latter was measured in an immunoradiometric assay with a sensitivity of 0.07 microU/ml. serum TSH was immunologically identical to standard TSH and did not decrease during a T3 suppression test. serum free alpha-subunit and the molar alpha-subunit to TSH ratio were high (6.1 ng/ml and 31.2, respectively). TRH administration induced significant increases in both GH ( 129%) and alpha-subunit ( 156%) levels. Conversely, dopamine infusion resulted in a decrease in serum GH (-66%) and alpha-subunit (-43%) levels, and subsequent administration of the dopamine antagonist sulpiride induced significant increases in both GH and alpha-subunit ( 393% and 106%, respectively). Similarly, somatostatin infusion inhibited GH (-43%) and alpha-subunit (-61%) secretion. serum TSH levels were not affected by TRH, dopamine, or somatostatin. The biological to immunological activity ratio of serum TSH purified by immunoaffinity chromatography and measured in an adenylate cyclase assay was significantly increased compared to that in serum from hypothyroid or euthyroid subjects [biological to immunological activity ratio, 6.9 /- 0.2 ( /- SD) vs. 4.4 /- 1.1; P less than 0.001]. In gel chromatography, the apparent mol wt of the patient's TSH was smaller than that of the controls. After adenomectomy, all of the altered parameters of pituitary function became normal. Double gold particle immunostaining of the adenomatous tissue showed that all of the cells contained secretory granules positive for GH and alpha-subunit, while very few cells were positive for TSH beta as well as GH and alpha-subunit. These data indicate that in this patient serum TSH had an apparent mol wt smaller than that of normal TSH and an increased biological activity which, along with the autonomous TSH secretion, account for hyperthyroidism in the presence of low normal TSH levels; alpha-subunit originated from the same adenomatous cells that secreted GH but not TSH, thus explaining the in vivo observation that alpha-subunit responses to several agents were dissociated from TSH responses and parallel to GH responses; and TSH and GH were colocalized in a minority of the neoplastic cells.- - - - - - - - - - ranking = 2keywords = chromatography (Clic here for more details about this article) |
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