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Biomedical subjects

E Horvath

Publications and source records attributed to E Horvath.

At least 199 records · Page 11Linked to original sources
PubMed1981

Massive Crooke's hyalinization in corticotroph cell adenomas of the human pituitary. A histological, immunocytological, and electron microscopic study of three cases.

Three women with Cushing's disease caused by ACTH-producing adenoma, underwent transsphenoidal tumour resection. Many adenoma cells showed massive accumulation of microfilaments indistinguishable from Crooke's hyalin material by light and electron microscopy. We believe that these tumours represent variants of ACTH-producing adenomas, and the accumulation of microfilaments is due to cortisol dependency.

Adenoma↗
PubMed1981

Five different adenomas derived from the rat adenohypophysis: immunocytochemical and ultrastructural study.

With the use of electron microscopic morphology and immunochemistry, 5 tumors were studied: a spontaneous prolactin-producing adenoma (LEP rats); an estrogen-induced intrasellar tumor (R-Amsterdam rats); and 3 transplanted tumors, MtT.W10 and MtT.W5 (WF rats) and MtT.F4 (F344 rats). All tumors were derived from rat adenohypophysis and are known to secrete prolactin, growth hormone, or adrenocorticotropic hormone. The spontaneous tumor consisted of a uniform population of cells containing only immunoreactive prolactin. In the estrogen-induced tumor, prolactin and growth hormone were localized in separate cell types with the use of the immunoperoxidase technique. In the MtT.W10 tumor, both immunoreactive prolactin and growth hormone were observed in the same cell and in separate cell types. In the MtT.F4 and MtT.W5 tumors, one cell type was identified that was characterized by lack of morphologic differentiation, reduced secretory granule number, and inconclusive immunopositivity.

Adenoma↗
PubMed1981

Enhanced responsiveness of lactotrophs in ectopic pituitaries to bromocryptine and estrone acetate.

Intrasellar and transplanted pituitaries removed from the same rats were studied using light microscopy, immunocytology, electron microscopy and ultrastructural morphometry following treatment with bromocryptine and/or estrone acetate. Ectopic lactotrophs of rats treated with bromocryptine showed an increase in storage granule size and number, which was not observed in the lactotrophs of corresponding intrasellar pituitaries. In lactotrophs of intrasellar and ectopic pituitaries, treatment with estrone acetate caused a decrease of storage granule size, while rough endoplasmic reticulum (RER) and Golgi region volume density increased. When rats were treated with a combination of bromocryptine and estrone acetate, intrasellar lactotrophs exhibited increased volume density and diameter size in forming granules as well as increased RER volume density. In ectopic lactotrophs, combined treatment led to a decrease in RER, volume densities of Golgi region and forming granules, as well as increased storage granule size. It can be concluded that ectopic lactotrophs were more sensitive to the inhibiting effects of bromocryptine treatment than intrasellar lactotrophs. Intrasellar lactotrophs were more susceptible to estrone acetate than bromocryptine treatment. As a result, the increased responsiveness of ectopic lactotrophs to estrone acetate was less conspicuous.

Animals↗
PubMed1981

Regulation of humoral immunity in rats by pituitary hormones.

Hypophysectomized female Fischer 344 and Wistar-Furth rats had severely impaired primary and secondary antibody responses to sheep red blood cells (SRBC). Mercaptoethanol-sensitive (IgM) and mercaptoethanol-resistant (IgG) antibodies were similarly affected. Titers to E. Coli 055:B5 lipopolysaccharide were also significantly decreased in such animals. The antibody response of hypophysectomized rats could be restored by syngeneic pituitary grafts when placed under the kidney capsule or by prolactin treatment. Growth hormone was less effective in this respect than prolactin. Treatment of normal rats with ACTH suppressed their antibody formation to SRBC. These results indicate that the pituitary gland has the potential to regulate humoral immune responses.

Adrenocorticotropic Hormone↗
PubMed1981

Response to thyrotropin-releasing hormone (TRH) of rat lactotrophs and somatotrophs deprived of hypothalamic control.

Intrasellar and ectopic lactotrophs and somatotrophs of intact and hypophysectomized rats were studied by histology, immunohistochemistry, electron microscopy and ultrastructural morphometry after 2 weeks of TRH treatment. Both ectopic lactotrophs and somatotrophs of hypophysectomized rats showed subcellular changes indicative of stimulation following TRH treatment. Ultrastructural morphometry revealed that in these ectopic lactotrophs, nuclear volume density decreased, while that of Golgi region and forming granules increased. Similar but less striking morphometric findings were noted in somatotrophs of this group and the intrasellar lactotrophs of treated nongrafted rats. Intrasellar somatotrophs showed increased nuclear volume density and reduced Golgi region volume density, following TRH administration. Ectopic lactotrophs and somatotrophs of intact animals were least responsive to treatment. These results indicate that both ectopic lactotrophs and somatotrophs of hypophysectomized rats are more sensitive to the stimulatory effects of TRH than those of intact animals.

Animals↗
PubMed1981

[Traumatic children's emergencies. An analytical and statistical study spreading over 6 years (author's transl)].

A study has been made of over 3800 children to determine the preventive measures and the possible prophylaxy of accidents by children. The traumatological emergencies are concerned. The study shows, by means of histograms, an increase of their frequency not withstanding the security measures which have been taken. Every kind of emergency is studied, with emphasis upon the fractures of pediatric surgery.

Adolescent↗
PubMed1980

Null cell adenoma of the human pituitary.

Among 343 surgically-removed pituitary adenomas, 56 tumors were unassociated clinically or biochemically with increased hormone secretion and contained no adenohypophysial hormones by the immunoperoxidase technique, except for 10 cases in which a few scattered cells showed positive immunostaining for beta-TSH or beta-FSH, beta-LH, prolactin and/or alpha-subunit. These tumors were chromophobic adenomas with no PAS, lead hematoxylin or carmoisine positivity and electron microscopy failed to reveal their morphogenesis. The term null cell adenoma of the pituitary is proposed to designate this tumor type. This term recognizes the most obvious features of these tumors: the absence of markers which would permit the disclosure of their cellular origin. Null cells are also found in the nontumorous adenohypophysis, suggesting that null cell adenomas derive from preexisting nonneoplastic null cells. The question of whether pituitary null cells are hormonally inactive committed precursors, uncommitted stem cells or dedifferentiated cells remains to be elucidated.

Adenoma↗
PubMed1980

Correlative ultrastructural morphometry of human prolactin-producing adenomas.

Ultrastructural morphometry was applied to 24 surgically removed human sparsely granulated prolactin cell adenomas in an attempt to correlate the measurements with blood prolactin levels, size of tumour, and age and sex of patient. No correlation was apparent. However, further evaluation revealed that correlation existed between size of tumour and blood prolactin levels, indicating that tumour mass, and not subcellular morphology, was related to the amount of prolactin released.

Adenoma↗
PubMed1980

Gonadotroph cell adenoma of the pituitary in a women with long-standing hypogonadism.

A 57-year-old woman, with long-standing hypogonadism secondary to irradiation of the ovaries, was found to have a pituitary tumor which was removed and investigated by histology, immunocytology and electron microscopy. Histologically, the tumor corresponded to a chromophobe, slightly PAS positive adenoma and the immunoperoxidase stain revealed the presence of both FSH and LH in the cytoplasm of the adenoma cells. The structural features of the adenoma cells resembled those of FSH cells in the nontumorous adenohypophysis. We thus believe that pituitary adenomas consisting of gonadotrophin-producing cells occur and that these may produce both FSH and LH. The relation between the gonadotrophin-producing adenoma and the preceding hypogonadism is uncertain.

Adenoma↗
PubMed1980

Leydig-like cells in the adrenals of a woman with ectopic ACTH syndrome.

A 36 year old woman with hypercorticism and markedly elevated blood ACTH levels underwent pituitary ablation because of suspected hypophysial Cushing's disease. Since no adenoma was detected in the anterior lobe and the hypercorticism persisted, a bilateral adrenalectomy was performed. Four months later lymph node and mediastinal metastases of an anaplastic small cell carcinoma, with the presence of argyrophil granulation, as well as immunoreactive 19-39ACTH, beta-LPH and alpha-endorphin, were found. The primary site of ectopic ACTH production was not revealed. A light and electron microscopic study of the adrenals, in addition to cortical hyperplasia, disclosed numerous small cells associated with nonmyelinated sympathetic nerve fibers and containing cytoplasmic inclusions indistinguishable from Reinke crystals. The Leydig-like cell-nonmyelinated nerve complexes, noted in both the adrenal cortex and medulla, showed perivascular localization, and their morphologic features were similar to those of hilus cells of the ovaries or extraglandular Leydig cells of the testis. The underlying mechanism accounting for the development of Leydig-like cells remained obscure; cytodifferentiation from pluripotent mesenchymal cells, possibly mediated by secretory products of sympathetic nerve fibers, may provide an explanation for their formation.

ACTH Syndrome, Ectopic↗
PubMed1980

Pituitary adenomas in old age.

Pituitaries obtained at unselected autopsies of 152 men and women over 80 years of age, dying of different diseases, have been investigated histologically by using various staining procedures, including the immunoperoxidase technique. In 20 pituitaries, 22 adenomas were found providing evidence that these tumors are common in aging subjects. In 9 adenomas out of 17 cases, the immunoperoxidase technique revealed the presence of prolactin, indicating that prolactin-producing adenomas constitute the most frequently occurring pituitary tumor type in old age. The presence of growth hormone was demonstrated in one adenoma which also contained prolactin. No storage of ACTH, FSH, LH or TSH was found in the tumors. The biologic behavior of pituitary adenomas disclosed as incidental findings in old age remains to be elucidated. These neoplasms may have a slower growth rate, but more work is required to establish whether they differ from those found in younger age groups.

Adenoma↗
PubMed1980

Pituitary prolactin cell hyperplasia.

In female Long-Evans rats, development of prolactin cell adenomas is preceded by hyperplasia of prolactin cells, suggesting that factors affecting the endocrine function of prolactin cells might have an important role in the genesis of prolactin-producing pituitary tumors.

Adenoma↗
PubMed1980

Thyrotroph cell adenoma of the human pituitary gland associated with primary hypothyroidism: clinical and morphological features.

The morphological features of a pituitary adenoma resected from a 39-year-old woman with hypothyroidism have been investigated. Hypothyroidism followed radioactive iodine treatment of pre-existing hyperthyroidism, presumably Graves' disease. Blood TSH was low during a euthyroid interval and was elevated above normal with the onset of hypothyroidism. The presence of a small amount of TSH was demonstrated in the tumour by radioimmunoassay. By conventional histology the tumour was a chromophobe adenoma. Some fine secretory granules stained with aldehyde thionin but were negative with PAS and contained no immunoreactive TSH. By light and electron microscopy, the tumour cells differed from thyroid deficiency cells. They were small and angular, containing numerous microtubules and small spherical secretory granules, oriented mainly along the plasma membranes. The tumour was considered to represent a thyrotroph cell adenoma, arising from protracted overstimulation secondary to chronic thyroid hormone deficiency.

Adenoma↗
PubMed1980

Pathogenesis of experimental adrenal hemorrhagic necrosis ("apoplexy"): ultrastructural, biochemical, neuropharmacologic, and blood coagulation studies with acrylonitrile in the rat.

The pathogenesis of experimental adrenal hemorrhagic necrosis produced by acrylonitrile in the rat was investigated by various morphologic, biochemical, and pharmacologic methods. One dose of this chemical injected intravenously caused 100 per cent incidence of adrenal hemorrhage and necrosis in 90 to 120 minutes. Electron microscopy, histochemistry, and light microscopy combined with colloidal carbon labeling suggested an early damage (30 minutes after administration of acrylonitrile) to the vascular endothelium in the adrenal cortex, prominent at 60 minutes, when lesion to the parenchymal cells was not visible. The use of extracellular diffusion tracer horseradish peroxidase further indicated that parenchymal cell injury was a late event. Damage to the vascular endothelium in the adrenal cortex was associated with retrograde embolization of medullary cells and cell fragments into the cortical capillaries. The ultrastructurally demonstrated platelet aggregation and fibrin precipitation at the sites of discontinuous vascular endothelium were accompanied by a decrease in circulating platelets and fibrinogen as well as prolongation of prothrombin, partial thromboplastin, and thrombin time. The concentration of dopamine, unlike that of noradrenaline, in the adrenals but not in the brain of rats injected with acrylonitrile showed a time-dependent elevation. Pretreatment with phenoxybenzamine (alpha-adrenergic antagonist) or labetalol (alpha- and beta-adrenergic blocker) or metyrapone (11-beta-hydroxylase inhibitor) and the depletion of catecholamines by reserpine or prior medullectomy prevented the chemically induced adrenal necrosis. These results indicate that the presence of a functional adrenal cortex is necessary for the development of cortical damage which is associated with early vascular lesion caused and/or modulated by vasoactive amines from the medulla and/or (metabolites of) acrylonitrile.

Acrylonitrile↗
PubMed1980

Silent corticotropic adenomas of the human pituitary gland: a histologic, immunocytologic, and ultrastructural study.

Among 300 surgically removed pituitary adenomas, 17 tumors containing immunoreactive 1-39 adrenocorticotropin (ACTH) and/or 19-39 ACTH, beta-lipotropin, and alpha-endorphin but unassociated with clinical signs of Cushing's disease have been detected. These neoplasms were divided into basophilic adenomas with strong periodic acid-Schiff (PAS) and lead-hematoxylin positivity and chromophobic tumors with moderate or no PAS and lead-hematoxylin positivity. The former were densely granulated tumors with a fine structure strikingly similar to that of functioning corticotropic cell adenomas. The latter were sparsely granulated with varying ultrastructural patterns. The marked morphologic diversity suggests that these adenomas, despite their similar immunocytologic characteristics, represent more than one entity. Clinically, the most common finding was a rapidly progressing visual defect. An unusually high incidence of infarction (5 cases) and recurrence (5 cases) was noted, underlining the importance of correct morphologic diagnosis and careful follow-up.

Adenoma↗
PubMed1980

Fine structural features of secretion in adenomas of human pituitary gland.

Ultrastructural investigation of 274 human pituitary adenomas and 39 nontumorous adenohypophyses revealed two distinct types of secretion. Exocytosis was characteristic of prolactin cell adenomas, mixed growth hormone-prolactin cell adenomas, acidophil stem cell adenomas, and nontumorous prolactin cells. The second type, termed "transmembrane effusion," was noted in corticotroph, thyrotroph, gonadotroph, undifferentiated cell adenomas, and oncocytomas, as well as nontumorous corticotrophs, thyrotrophs, and gonadotrophs. It differed from that of prolactin cells and resembled diacrine secretion of gastrointestinal gastrin cells and membrane release in the neurohypophysis. In adenomatous and nontumorous growth hormone cells, neither exocytosis nor transmembrane effusion were apparent, hence a third type of release is suggested. Electron microscopic study of release mechanisms is helpful in the differential diagnosis of pituitary adenomas, since discharge of secretory products is not identical in the various tumor types.

Adenoma↗
PubMed1980

Intrasellar solitary plasmacytoma terminating in multiple myeloma: a report of a case including electron microscopical study.

A case of multiple myeloma is reported that presented as a solitary plasmacytoma of the bone of the sella turcica. The diagnosis was established by electron microscopy in conjunction with the immunoperoxidase technique. The patient succumbed 37 months after the diagnosis was made. The relation between solitary plasmacytoma of bone and multiple myeloma is discussed. The differential diagnosis of intrasellar tumors may pose serious problems to the surgical pathologist. In difficult cases the value of the immunoperoxidase technique and electron microscopy is emphasized.

Female↗