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Query: UMLS:C0001430 (adenoma)
 21,222 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

85 surgically removed pituitary adenomas were studied by light and electron microscopical and in part immunohistochemical methods. The tumors were histogically classified and reexamined by the ultrastructure. Histochemically the adenomas could be differentiated in acidophil adenomas (1. group, 41%), mucoid cell adenomas (2. group, 6%), and chromophobe adenomas (3. group, 37%) whereas oncocytic adenomas (4. group, 16%) could be identified only in plastic-embedded sections. About half of the acidophil adenomas were highly differentiated and showed structures which correspond to those of normal STH cells (subgroup 1.1). 1 adenoma consisted of cells of prolactin type (subgroup 1.2). The other acidophil adenomas were differentiated to a lower degree and showed no resemblance to the structures of normal acidophil cells. The 5 mucoid cell adenomas were proved to be with all methods highly differentiated adenomas of ACTH-cell type (subgroup 2.1). TSH-cell adenomas (subgroup 2.2) and lower differentiated mucoid cell adenomas (subgroup 2.0) were lacking in our collection. More than one third of the chromophobe adenomas showed well developed endoplasmic reticulum and Golgi complexes. The other had little and small organellas that resemblances to immature stem cells were evident. The oncocytic adenomas were identified in plastic-embedded sections by their fine-granular structures which were based ultrastructurally not on small secretory granules but on closely arranged mitochondrias.
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PMID:[Light and electron microscopic studies for classification of pituitary adenomas (author's transl)]. 12 39

Enzyme histochemical and ultrastructural studies of a "dexamethasone-suppressed" virilizing adrenocortical adenoma and the attached cortex revealed that tumor cells showed little activities of some lysosomal enzymes and scarcity of lipofuscins and dense bodies of lysosomal type, forming a marked contrast to the cells of zona reticularis and the virilizing adenomas previously reported. The other findings of tumor cells, such as a pattern of activities of dehydrogenases including 3beta-hydroxysteroid dehydrogenase and the morphology of mitochondria, were those of reticularis cells. The findings showed that scantiness of lipofuscins did not rule out the possibility of adenoma producing adrenal androgen, dehydroepiandrosterone. Most of the tumor cells as well as reticularis cells were positive for alkaline phosphatase, the activity of which was interpreted as the effect of ACTH stimulation.
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PMID:Enzyme histochemical and electron microscopic study of a virilizing adrenocortical adenoma. 15 60

Isolated adrenal cells were obtained surgically from patients with primary aldosteronism, breast cancer, or Cushing's syndrome. They were prepared by the modification of Sayers method, and incubated at 37 degrees C for 2 hours under 95% O-2-5% CO-2, in the medium of calcium-free Krebs-Ringer bicarbonate buffer containing 0.2% glucose and 0.5% bovine serum albumin, to which various doses of calcium, ACTH, dibutyryl cyclic AMP or cycloheximide were added. Steroid production was measured by the method of Silber et al. In isolated normal adrenocortical cells, 11-OHCS was produced by calcium alone in the absence of ACTH or dibutyryl cyclic AMP, while it was not produced by ACTH alone without calcium. 11-OHCS production by ACTH was decreased in the high concentration of calcium (10.16 mM, 12.70 mM). Cycloheximide partially blocked an increase in 11-OHCS synthesis induced by calcium. These data suggest that adenyl cyclase of human adrenocortical cells may be stimulated by calcium alone, supporting the notion that calcium is a second messenger. The ratio of 11-OHCS production by calcium alone to that by dibutyryl cyclic AMP was higher in adenoma cells than in normal cells. This may account for the character of autonomic steroid production in adrenocortical adenoma cells.
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PMID:[Effect of calcium on steroidogenesis in isolated human adrenal cells (author's transl)]. 16

The ultrastructure of the adrenal cortex was studied by quantitative stereologic techniques in LAF1 mice bearing a transplantable, ACTH-secreting pituitary tumor (AtT). The tumor stimulated a significant increase in volume and surface area of smooth endoplasmic reticulum and mitochondrial membranes in all three zones of the adrenal cortex. Concomitantly, plasma corticosterone was increased significantly in tumor-bearing animals. The AtT was an adenoma of the chromophobe type. Continuity of the nuclear membrane with the rough endoplasmic reticulum was readily observed in tumor parenchymal cells.
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PMID:Quantitative study on the effect of an ACTH-producing pituitary tumor on the ultrastructure of the mouse adrenal gland. 16

Trans-membrane potentials and steroidogenesis were measured in superfused slices of non-tumor and neoplastic human adrenocortical tissue. Non-tumor tissue was obtained at the time for renal transplant or from tissue removed along with tumors. Non-tumor human adrenocortical tissue had electrophysiological and steroidogenic properties similar to those of the rat and rabbit. In normal medium ACTH stimulated steroidogenesis but had no effect on the membrane potential. In K+-free medium, the cells hyperpolarized, and subsequent addition of ACTH caused depolarization. Trans-membrane potentials of adrenocortical tumors were lower than those of non-tumor cells. Ommission of K+ from the medium caused hyperpolairzation of the tumor cells, but the trans-membrane potentials did not reach the values of hyperpolarized non-tumor cells. ACTH, added to the K+-free medium, caused little or no change in membrane potential of tumor cells except in one case of a virilizing adenoma, which responded very much like non-tumor tissue. Except for the virilizing adenoma, tumor tissue slices produced little or no detectable fluorogenic steroid, even in the presence of large amounts of ACTH or cyclic AMP. The virilizing adenoma responded with increased steroidogensis to ACTH and cyclic AMP.
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PMID:Transmembrane potentials and steroidogenesis in normal and neoplastic human adrenocortical tissue. 17 Feb 96

Bilaterally adrenalectomized patients (18) because of Cushing's syndrome were studied. 16 of these 18 persons exhibited fairly high plasma ACTH levels. Distinctly elevated plasma ACTH levels were observed in 6 of them. 5 patients of this group showed an enlarged sella and deep pigmentation of the skin. 4 of the latter group had a mucoid cell adenoma which was removed selectively. After the surgery the ACTH values were found to be within normal range without any significant endocrine dysfunction of the pituitary. A long-term ACTH survey revealed that the ACTH levels remained within the ranges of bilaterally adrenalectomized Cushing patients without concomitant enlargement of the sella or pigmentation.
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PMID:[Plasma ACTH and Nelson tumors in bilaterally adrenalectomized Cushing patients]. 17 74

Corticotrophic secretion has been studied in several groups of subjects during metopirone test and arginine L-Dopa infusion. In animals, a net plasma ACTH increase is observed under while it is inconstant after arginine L-Dopa. In hypopituitarism, metopirone ACTH levels are low and unchanged during the tests. In chromophobe adenoma, basal ACTH levels are high, ACTH increase is normal during test and significantly higher than in controls after L-Dopa injection. Significance of these metopirone corticotrophic abnormalities is discussed.
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PMID:[Anomalies of corticotropin secretion in chromophobe adenomas]. 17 37

A human adrenocortical adenoma was cultivated in vitro and the morphological characteristics, steroidogenic activity and response to ACTH of the cultured cells were studied over a period of about two months. At first, the morphology of the cultures was similar to that of the original tissue. This structure changed in the course of time and the cells underwent fibroblastoid transformation. Stimulation with ACTH evoked two types of morphological response: a) a short-term response, whereby an extensive but rapidly reversible vacuolization was followed by cell enlargement and granulation, and b) a long-term effect in which the differentiated cell morphology was maintained. The cultures showed a low steroidogenic activity throughout the experiment. ACTH stimulation increased the total 17-hydroxysteroid production up to 10-fold. After ACTH withdrawal the corticosteroid levels declined slowly and about 50% of the maximal activity persisted on the fifth day after ACTH withdrawal.
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PMID:A human adrenocortical adenoma in tissue culture. Morphology and hormone secretion. 17 70

A chromophobic pituitary adenoma induced on BD IX-rats has been grafted on animals of the same strain. The transplanted tumour takes in 90-100%; it grows at a slow rate (in 7 months after grafting a weight of 7-20 g is attained). Tumour-bearing animals display gigantism and hypertrophy of adrenals; moreover, in 33% of cases, diabetes is observed. With non-diabetic animals, splenomegaly and marked leukocytosis are observed; immature white and red cells are present in the peripheral blood. Spontaneous regression of the tumour never occurs. After surgical removal, tumour regrowth and the formation of metastases are observed. Diabetes is characterised by pronounced hyperglycaemia, glucosuria, polyphagia and polydipsia. Histochemically, insulin cannot be detected in pancreas. Splenomegaly is never observed in diabetic animals. Transplanted adenoma frequently tends to stop growing. No recurrence is observable after extirpation. Spontaneous regression of the tumour sometimes occurs. Gigantism, hypertrophy of adrenals and diabetes are considered as consequences of growth hormone- and ACTH-secretion of the transplanted adenoma. At present the tumour is running in the 8th passage. It did not change its characteristics over a period of 5 years.
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PMID:Transplantable, STH-producing and diabetogenic pituitary adenoma of the BD IX-strain of rats. 17 13

Eight patients with Nelson's syndrome were treated with a pituitary implant of yttrium-90 or gold-198 four to 16 years after adrenal surgery. All had considerable pigmentation. One already had cranial nerve abnormalities and visual field defects and had had both a craniotomy and deep x-ray treatment. Radiographs showed that the pituitary fossa was abnormal in seven patients. A biopsy performed in six cases showed mucoid (or basophil) adenoma in all. In the four specimens examined ACTH was identified by electron microscopy or immunofluorescence, or both. Patients were followed up after pituitary implantation for three months to 12 years. All showed decreased pigmentation, and six became normal. Four patients regained normal ACTH levels and the other two studied had decreased levels. In no case did new cranial nerve disease or further sellar expansion develop since operation, and two patients showed remodelling of the sella. Complications were temporary leakage of cerebrospinal fluid and diabetes insipidus in one patient and gonadotrophin deficiency in another.
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PMID:Treatment of Nelson's syndrome by pituitary implantation of yttrium-90 or gold-198. 18 13


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