Microscopic investigation into liquefaction resistance of pre-sheared sand: Effects of particle shape and initial anisotropy

Germfree state and food restriction have been shown to increase life span and delay tumor occurrence in rats. We report here the histologic, immunocytochemical and electron microscopic findings of adenohypophyses of aging, male Lobund-Wistar rats raised at Lobund Laboratories. In our previous study, the morphologic changes in the adenohypophyses of old rats have been extensively investigated by histology, immunocytochemistry and electron microscopy. Lactotroph adenomas were frequent in Long-Evans and Sprague-Dawley rats, whereas gonadotroph adenomas were frequent in Sprague-Dawley and Wistar rats.Male Lobund-Wistar rats were divided into four groups: 1) conventional, which were raised under normal non-germfree environment and received food ad libitum; 2) germfree-food ad libitum; 3) conventional environment-food restricted and 4) germfree-food restricted. The adenohypophyses were removed from 6-month-, 18-month- and 30-month-old rats. For light microscopy, adenohypophyses were fixed in formalin and embedded in paraffin.

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An Electron Microscopic Study of the Acute Effects of Hypothalamic Releasing Factors on the Anterior Pituitary Gland

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100100901 ◽

1968 ◽

Vol 26 ◽

pp. 232-233

Author(s):

P.W. Coates ◽

E.A. Ashby ◽

L. Krulich ◽

A. Dhariwal ◽

S. McCann

Keyword(s):

Anterior Pituitary ◽

Microscopic Investigation ◽

Uranyl Acetate ◽

Electron Microscopic Investigation ◽

Electron Microscopic ◽

Tissue Samples ◽

Thin Sections ◽

Dense Membrane ◽

Membrane Bound ◽

Releasing Factors

The morphologic effects on somatotrophs of crude sheep hypothalamic extract prepared from stalk-median eminence were studied by electron microscopy in conjunction with concurrently run bioassays performed on the same tissue samples taken from young adult male Sherman rats.Groups were divided into uninjected controls and injected experimentals sacrificed at 5', 15', and 30' after injection. Half of each anterior pituitary was prepared for electron microscopic investigation, the other half for bioassay. Fixation using collidine buffered osmium tetroxide was followed by dehydration and embedment in Maraglas. Uranyl acetate and lead citrate were used as stains. Thin sections were examined in a Philips EM 200.Somatotrophs from uninjected controls appeared as described in the literature (Fig. 1). In addition to other components, these cells contained moderate numbers of spherical, electron-dense, membrane-bound granules approximately 350 millicrons in diameter.

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Fine Structural Classification of Chromophobe Adenomas of the Human Pituitary Gland

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100115511 ◽

1975 ◽

Vol 33 ◽

pp. 378-379

Author(s):

K. Kovacs ◽

E. Horvath

Keyword(s):

Pituitary Adenomas ◽

Secretory Activity ◽

Microscopic Investigation ◽

Uranyl Acetate ◽

Electron Microscopic Investigation ◽

Electron Microscopic ◽

Human Pituitary ◽

Cytoplasmic Staining ◽

Human Pituitary Gland ◽

Microscopic Features

Chromophobe pituitary adenomas arise from adenohypophysial cells and fail to exhibit cytoplasmic staining with conventional acid or basic dyes by light microscopy. The aim of the present work was to study the electron microscopic features of these tumors, to separate them into distinct entities and to correlate their fine structural appearances with secretory activity.Among 48 surgically removed various pituitary adenomas 30 tumors were found which, based on the tinctorial characteristics of the cytoplasm, corresponded to chromophobe adenomas. For electron microscopic investigation pieces of these tumors were fixed in 2.5 per cent glutaraldehyde in Sorensen's buffer, post fixed in 1 per cent osmium tetroxide in Millonig's buffer, dehydrated in graded ethanol and embedded in Epon 812. Ultrathin sections were stained with uranyl acetate and lead citrate.By electron microscopy it was possible to separate chromophobe adenomas into 3 distinct entities: 1) adenomas consisting of sparsely granulated growth hormone cells (7 cases).

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Temporal and spatial interrelationships of confronting cisternae to nuclear envelope

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100125051 ◽

1992 ◽

Vol 50 (1) ◽

pp. 930-931

Author(s):

John R. Palisano

Keyword(s):

Endoplasmic Reticulum ◽

Nuclear Envelope ◽

Tumor Cells ◽

Hela Cells ◽

Microscopic Investigation ◽

Electron Microscopic Investigation ◽

Serial Sections ◽

Electron Microscopic ◽

Fetal Rat ◽

Temporal And Spatial

Although confronting cistemae (CC) have been observed in a variety of tumor cells and normal fetal rat, mouse, and human epithelial tissues, little is known about their origin or role in mitotic cells. While several investigators have suggested that CC arise from nuclear envelope (NE) folding back on itself during prophase, others have suggested that CC arise when fragments of NE pair with endoplasmic reticulum. An electron microscopic investigation of 0.25 um thick serial sections was undertaken to examine the origin of CC in HeLa cells.

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Electron Microscopic investigation of crooke’s change in the pituitaries of patients with hypercorticism

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100156225 ◽

1989 ◽

Vol 47 ◽

pp. 848-849

Author(s):

E. Horvath ◽

K. Kovacs ◽

L. Stefaneanu ◽

N. Losinski

Keyword(s):

Nucleolar Organizer ◽

Microscopic Investigation ◽

Electron Microscopic Investigation ◽

Ectopic Acth Syndrome ◽

Nucleolar Organizer Regions ◽

Electron Microscopic ◽

Human Pituitary ◽

Ectopic Acth ◽

Crooke’S Hyalinization

Human pituitary corticotropins have unique morphologic markers: bundles of type-1 filaments, measuring approximately 70 A in width and representing cytokeratin. The extreme ring-like accumulation of type-1 filaments, known as Crooke's hyalinization, signals functional suppression of the corticotropins and occurs in endogenous and exogenous glucocorticoid excess, caused by ACTH-secreting pituitary adenoma, glucocorticoid secreting adrenocortical tumor, ectopic ACTH-syndrome and administration of pharmacologic doses of glucocorticoids. Cells of autonomous corticotroph adenomas usually do not show Crooke's hyalin change. A minority of these tumors, however, retains sensitivity to the negative feed-back effect of elevated blood glucocorticoid levels and display typical Crooke’s change.In the present study pituitary corticotropins in various phases of Crooke's hyalinization were investigated in patients with glucocorticoid excess of various origin, applying histology, immunocytochemistry, count of argyrophilic nucleolar organizer regions (AgNOR), and transmission electron microscopy.

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