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Biomedical subjects

E Horvath

Publications and source records attributed to E Horvath.

At least 271 records · Page 15Linked to original sources
PubMed1975

Gonadotrophs following removal of the ovaries: a fine structural study of human pituitary glands.

The fine structure of gonadotrophs has been investigated in surgically removed pituitary glands of 12 women who because of disseminated breast cancer, underwent bilateral ovariectomy at various periods before hypophysectomy. Compared with the adenohypophyses of 3 non-ovariectomized female subjects with diabetes mellitus, electron microscopy revealed that two cell types were affected by gonadectomy. These cell types corresponded to those which were regarded as FSH gonadotrophs and LH gonadotrophs in previous studies. In addition in the adenohypophyses stimulated by removal of the ovaries, intermediary cell types began to appear suggesting a transformation of LH gonadotrophs to FSH gonadotrophs. The most conspicuous change following gonadectomy was the formation of castration cells. These cells arose from FSH gonadotrophs and exhibited ultrastructural features interpreted as representing the morphologic manifestations of sustained hypersecretion of gonadotrophins. It seemed that castration cells have a limited life span and in their advanced stages of development they show ultrastructural signs indicative of irreversible involution.

Adult↗
PubMed1975

Mitochondrial origin of centrioles and cilia in some human endocrine neoplasms.

Fine structural investigation of surgically removed human pituitary and parathyroid adenomas, pheochromocytomas and bronchial carcinoids revealed a hitherto undetected sequence of events in the formation of centrioles and cilia indicating that mitochondria may serve as their progenitors. The first steps seem to be the disappearance of mitochondrial cristae and a polar accumulation of a fibrillar-granular material with a subsequent increase of electron density of the double mitochondrial membranes and deposition of more electron opaque substance within and around these procentriolar bodies. This process is followed by the disintegration of the double membranes and an asymmetrical division of the electron dense aggregate. The larger part seems to be the precursor of the primary centriole (basal body) whereas the smaller one that of the secondary centriole. Formation of centrioleand rudimentary cilium-like structures was disclosed within the unaltered mitochondrial membranes of oncocytic cells present in two pituitary adenomas and in one pheochromocytoma. Accumulation of procentriolar bodies and mature centrioles, noted in some tumors, may be due to a defect in the process of centriolo- and ciliogenesis. It is conceivable that the mitochondrial genome plays an important role in formation of centrioles and cilia.

Adenoma↗
PubMed1975

Pituitary adenoma producing amyloid-like substance.

Light and electron microscopical examination of a pituitary adenoma showed that the tumor was composed of prolactin cells that produced amyloid-like material. The findings have been interpreted in favor of the role of rough endoplasmic reticulum in amyloid fibril formation within the adenoma cells. Histochemical and fine structural data indicate that the material produced by this tumor resembles apudamyloid rather than immunoamyloid.

Adenoma, Chromophobe↗
PubMed1974

Origin, possible function and fate of "follicular cells" in the anterior lobe of the human pituitary.

In human anterior pituitaries, follicular structures were found to develop by transformation of various types of glandular cells around foci of ruptured granulated cells undergoing destruction. In phase I, junctional complexes between granulated cells, as well as microvilli at the luminal surfaces of cell membranes, are formed. In phase II, degranulation and dedifferentiation of cytoplasm dominate the picture. Phase III follicular cells are practically devoid of secretory granules and other ultrastructural features characteristic of granulated cells. The participation of cell types in follicle formation does not appear to be limited. The follicular content in phase I-II is clearly recognizable as cellular debris from adenohypophysiocytes. These findings indicate that neither follicles nor junctional complexes are necessarily permanent structures of the anterior pituitary. It can be assumed that substances escaping from ruptured granulated cells may induce the formation of junctional complexes between adjacent cells.

Basement Membrane↗