Two Distinct Types of Microfilaments in the Cytoplasm of Human Adenohypophysial Cells

1973 ◽  
Vol 31 ◽  
pp. 668-669
Author(s):  
E. Horvath ◽  
K. Kovacs ◽  
I. E. Stratmann ◽  
C. Ezrin
Keyword(s):  
Pituitary Tumors ◽  
Average Diameter ◽  
Anterior Lobe ◽  
Uranyl Acetate ◽  
Type I ◽  
Breast Cancer Patients ◽  
Human Pituitary ◽  
Severe Diabetes ◽  
Pituitary Glands ◽  
Membrane Bound

Surgically removed human pituitary glands as well as pituitary tumors fixed in glutaraldehyde, postfixed in osmium tetroxide, embedded in epon resin, stained with uranyl acetate and lead citrate have been investigated by electron microscopy in order to correlate ultrastructure with functional activity. In the course of this study two distinct types of microfilaments have been identified in the cytoplasm of adenohypophysiocytes.Type I microfilaments (Fig. 1) were found in the cytoplasm of anterior lobe cells of five female subjects with disseminated mammary cancer and two patients with severe diabetes mellitus. The breast cancer patients were treated pre-operatively for various periods of time with different doses of oxysteroids. The microfilaments had an average diameter of JO A, formed parallel bundles, were scattered irregularly in the cytoplasm and were frequently located in the perikaryon. They were not membrane-bound and failed to show any periodicity.

Fine Structural Changes in the Adenohypophyses of Rats Following Destruction of the Pituitary Stalk

1977 ◽  
Vol 35 ◽  
pp. 496-497
Author(s):  
K. Kovacs ◽  
E. Horvath ◽  
J. M. Bilbao ◽  
F. A. Laszlo ◽  
I. Domokos
Keyword(s):  
Structural Changes ◽  
Tissue Injury ◽  
Anterior Lobe ◽  
Uranyl Acetate ◽  
Male Rats ◽  
Pituitary Stalk ◽  
Sequence Of Events ◽  
Pituitary Glands ◽  
Electrolytic Lesions ◽  
Ultrathin Sections

Electrolytic lesions of the pituitary stalk in rats interrupt adenohypophysial blood flow and result in massive infarction of the anterior lobe. In order to obtain a deeper insight into the morphogenesis of tissue injury and to reveal the sequence of events, a fine structural investigation was undertaken on adenohypophyses of rats at various intervals following destruction of the pituitary stalk.The pituitary stalk was destroyed electrolytically, with a Horsley-Clarke apparatus on 27 male rats of the R-Amsterdam strain, weighing 180-200 g. Thirty minutes, 1,2,4,6 and 24 hours after surgery the animals were perfused with a glutaraldehyde-formalin solution. The skulls were then opened and the pituitary glands removed. The anterior lobes were fixed in glutaraldehyde-formalin solution, postfixed in osmium tetroxide and embedded in Durcupan. Ultrathin sections were stained with uranyl acetate and lead citrate and investigated with a Philips 300 electron microscope.

scholarly journals The Upregulation of Molecules Related to Tumor Immune Escape in Human Pituitary Adenomas

2021 ◽  
Vol 12 ◽  
Author(s):  
Zhiyu Xi ◽  
Pamela S. Jones ◽  
Masaaki Mikamoto ◽  
Xiaobin Jiang ◽  
Alexander T. Faje ◽  
...  
Keyword(s):  
Immune Checkpoint ◽  
Pituitary Adenomas ◽  
Immune Escape ◽  
Pituitary Tumors ◽  
Human Pituitary ◽  
Tumor Immune Escape ◽  
Human Pituitary Adenomas ◽  
Pituitary Glands ◽  
Normal Human ◽  
Checkpoint Receptors

Human pituitary adenomas are one of the most common intracranial neoplasms. Although most of these tumors are benign and can be treated medically or by transsphenoidal surgery, a subset of these tumors are fast-growing, aggressive, recur, and remain a therapeutic dilemma. Because antibodies against immune checkpoint receptors PD-1 and CLTA-4 are now routinely used for cancer treatment, we quantified the expression of mRNA coding for PD-1, CLTA-4, and their ligands, PD-L1, PD-L2, CD80, and CD86 in human pituitary adenomas and normal pituitary glands, with the ultimate goal of exploiting immune checkpoint therapy in aggressive pituitary adenomas. Aggressive pituitary adenomas demonstrated an increased expression of PD-L2, CD80, and CD86 in compared to that of normal human pituitary glands. Furthermore, aggressive pituitary tumors demonstrated significantly higher levels of CD80 and CD86 compared to non-aggressive tumors. Our results establish a rationale for studying a potential role for immune checkpoint inhibition therapy in the treatment of pituitary adenomas.

scholarly journals Overexpression of Wild-Type Activin Receptor Alk4-1 Restores Activin Antiproliferative Effects in Human Pituitary Tumor Cells

2002 ◽  
Vol 87 (10) ◽  
pp. 4741-4746 ◽  
Author(s):  
Daniel C. Danila ◽  
Xun Zhang ◽  
Yunli Zhou ◽  
Jaafar N. Sleiman Haidar ◽  
Anne Klibanski
Keyword(s):  
Cell Proliferation ◽  
Cell Line ◽  
Pituitary Tumor ◽  
Pituitary Tumors ◽  
Type I ◽  
Wild Type ◽  
Human Pituitary ◽  
Activin Signaling ◽  
Hp75 Cells ◽  
Human Pituitary Tumor

Activin is a member of the TGFβ family of cytokines involved in the control of cell proliferation. We have previously shown that the majority of clinically nonfunctioning pituitary tumors do not respond to activin-induced growth suppression. Human pituitary tumors specifically express alternatively spliced activin type I receptor Alk4 mRNAs, producing C-terminus truncated isoforms designated Alk4-2, 4-3, and 4-4. However, it is not known whether these truncated activin receptors suppress activin effects on cell proliferation in human pituitary cells. Therefore, we investigated activin signaling in a human pituitary tumor cell line, HP75, derived from a clinically nonfunctioning pituitary tumor. HP75 cells express activin A mRNA and secrete activin A, as measured by ELISA and a functional bioassay. TGFβ administration decreases the proliferation of HP75 cells, suggesting that the signaling pathway shared by TGFβ and activin is functional in this cell line. However, activin neither inhibits cell proliferation nor stimulates reporter gene expression in HP75 cells, indicating that activin signaling is specifically blocked at the receptor level. HP75 cells express all truncated activin type I receptor Alk4 isoforms, as determined by RT-PCR. Because truncated Alk4 receptor isoforms inhibit activin signaling by competing with the wild-type receptor for binding to activin type II receptors, we hypothesized that overexpression of wild-type activin type I receptor will restore activin signaling. In HP75 cells, cotransfection of the wild-type activin type I receptor Alk4-1 expression vector increases activin-responsive reporter activity. Furthermore, transfection with wild-type activin receptor type I results in activin-mediated suppression of cell proliferation. These data indicate that truncated Alk4 isoforms interfere with activin signaling pathways and thereby may contribute to uncontrolled cell growth. Overexpression of the wild-type Alk4-1 receptor restores responsiveness to activin in human pituitary tumor-derived cells.

Ultrastructural features of human pituitary adenomas producing growth hormone, prolactin and thyrotrophin

1983 ◽  
Vol 41 ◽  
pp. 772-773
Author(s):  
E. Horvath ◽  
K. Kovacs ◽  
B. W. Scheithauer
Keyword(s):  
Growth Hormone ◽  
Pituitary Adenomas ◽  
Pituitary Tumors ◽  
Uranyl Acetate ◽  
Structural Studies ◽  
Elevated Blood ◽  
Cell Type ◽  
Human Pituitary ◽  
Ultrathin Sections ◽  
Tsh Levels

The majority of pituitary adenomas are monohormonal and monomorphous, i.e. they produce only one hormone and are composed of one morphologic cell type. About 12-15% of pituitary adenomas are piurihormonal containing more than one hormone, either in one cell type (monomorphous) or 2 or more morphologic types (plurimorphous). Most piurihormonal adenomas produce growth hormone and prolactin. Other combinations are uncommon.We report here the ul trastructural features of 11 pituitary tumors which produced growth hormone (GH), prolactin (PRL) and thyrotrophin (TSH), as shown by immunohistochemistry. They were removed by surgery from 3 men and 8 women between 24 and 63 years of age. Eight tumors were associated with elevated blood GH levels and acromegaly. In 3 patients, blood prolactin levels were elevated. Hyperthyroidism was evident in 1 woman with elevated blood TSH levels.For fine structural studies, parts of tissue were fixed in 2.5% glutaraldehyde, postosmicated in 1% OsO4, dehydrated in graded ethanol, processed through propylene oxide and embedded in an Epon-Araldite mixture. Ultrathin sections were stained with uranyl acetate and lead citrate and investigated with a Philips 300 electron microscope.

Distribution of Cystatin C (γ-Trace), an Inhibitor of Lysosomal Cysteine Proteinases, in the Anterior Lobe of Simian and Human Pituitary Glands

1985 ◽  
Vol 41 (5) ◽  
pp. 400-404 ◽  
Author(s):  
Christina A. Möller ◽  
Helge Löfberg ◽  
Anders O. Grubb ◽  
Sven-Olle Olsson ◽  
M. Elisabeth Davies ◽  
...  
Keyword(s):  
Cystatin C ◽  
Anterior Lobe ◽  
Cysteine Proteinases ◽  
Human Pituitary ◽  
Pituitary Glands

Pituitary Follicular Cells: Their Origin, Possible Function and Fate

1974 ◽  
Vol 32 ◽  
pp. 34-35
Author(s):  
E. Horvath ◽  
K. Kovacs ◽  
G. Penz ◽  
C. Ezrin
Keyword(s):  
Fine Structure ◽  
Secretory Granules ◽  
Follicular Cells ◽  
Human Pituitary ◽  
Rat Pituitary ◽  
Pituitary Glands ◽  
Junctional Complexes

Follicular structures, in the rat pituitary, composed of cells joined by junctional complexes and possessing few organelles and few, if any, secretory granules, were first described by Farquhar in 1957. Cells of the same description have since been observed in several species including man. The importance of these cells, however, remains obscure. While studying human pituitary glands, we have observed wide variations in the fine structure of follicular cells which may lead to a better understanding of their morphogenesis and significance.

Membrane-bound vesicles associated with the microvilli in the midgut of the freshwater microcrustacean, Daphnia magna

1983 ◽  
Vol 41 ◽  
pp. 480-481
Author(s):  
Patricia L. Jansma
Keyword(s):  
Daphnia Magna ◽  
Intestinal Epithelial Cells ◽  
Uranyl Acetate ◽  
Intestinal Epithelial ◽  
Chlamydomonas Reinhardii ◽  
Thin Sections ◽  
Saturated Water ◽  
Cacodylate Buffer ◽  
Membrane Bound ◽  
Ethanol Series

The presence of the membrane bound vesicles or blebs on the intestinal epithelial cells has been demonstrated in a variety of vertebrates such as chicks, piglets, hamsters, and humans. The only invertebrates shown to have these microvillar blebs are two species of f1ies. While investigating the digestive processes of the freshwater microcrustacean, Daphnia magna, the presence of these microvillar blebs was noticed.Daphnia magna fed in a suspension of axenically grown green alga, Chlamydomonas reinhardii for one hour were narcotized with CO2 saturated water. The intestinal tracts were excised in 2% glutaraldehyde in 0.2 M cacodyl ate buffer and then placed in fresh 2% glutaraldehyde for one hour. After rinsing in 0.1 M cacodylate buffer, the sample was postfixed in 2% OsO4, dehydrated with a graded ethanol series, infiltrated and embedded with Epon-Araldite. Thin sections were stained with uranyl acetate and Reynolds lead citrate before viewing with the Philips EM 200.

Labelling of non-A, non-B hepatitis infected chimpanzee hepatocytes with nuclease-gold conjugates

1984 ◽  
Vol 42 ◽  
pp. 250-251
Author(s):  
G. D. Gagne ◽  
M. F. Miller ◽  
D. A. Peterson
Keyword(s):  
Endoplasmic Reticulum ◽  
Experimental Infection ◽  
Uranyl Acetate ◽  
Type I ◽  
Cellular Injury ◽  
Type Ii ◽  
Tubular Structures ◽  
Type Iii ◽  
Type Iv ◽  
Infected Chimpanzee

Experimental infection of chimpanzees with non-A, non-B hepatitis (NANB) or with delta agent hepatitis results in the appearance of characteristic cytoplasmic alterations in the hepatocytes. These alterations include spongelike inclusions (Type I), attached convoluted membranes (Type II), tubular structures (Type III), and microtubular aggregates (Type IV) (Fig. 1). Type I, II and III structures are, by association, believed to be derived from endoplasmic reticulum and may be morphogenetically related. Type IV structures are generally observed free in the cytoplasm but sometimes in the vicinity of type III structures. It is not known whether these structures are somehow involved in the replication and/or assembly of the putative NANB virus or whether they are simply nonspecific responses to cellular injury. When treated with uranyl acetate, type I, II and III structures stain intensely as if they might contain nucleic acids. If these structures do correspond to intermediates in the replication of a virus, one might expect them to contain DNA or RNA and the present study was undertaken to explore this possibility.

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

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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