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At least 19 recordsLinked to original sources
PubMed1978

Effects of asbestos on epithelioid cell lines.

The in vitro effects of asbestos fibers on the growth and viability of CHO cells, an epithelioid cell line derived from Chinese hamster ovary, and on K-22 cells, an epithelial cell line derived from rat liver, have been studied. Relatively low concentrations of asbestos (10 micrograms/ml) were quite cytotoxic to both cell types. A sample of chrysotile asbestos was more toxic than samples of crocidolite or amosite. The toxic factor could not be extracted from the asbestos and toxicity occurred only if there was physical contact between the fibers and the cells. Although the phorbol ester class of tumor promoters induces the synthesis of plasminogen activator in various cell cultures, asbestos did not induce this protease in epithelioid or fibroblast cell cultures. The results obtained are compared to previous in vitro results obtained with fibroblast or macrophage cultures and are discussed in terms of their possible relevance to asbestos-induced fibrosis and tumorigenesis.

Animals↗
PubMed1976

Ultrastructural studies on the secretory process in the epithelioid cells of the juxtaglomerular apparatus.

The epithelioid cells of the juxtaglomerular apparatus have been studied with respect to the release mechanism of the secretory granules. Invaginations of the plasma membrane into the interior of the epithelioid cells are interpreted as stages before or after an exocytotic process. Granules are sometimes observed in close contact with the plasma membrane, and material with electron density similar to that of the granules can also be observed in the invaginations. These morphological features suggest that the granular material of the epithelioid cells is extruded into the texture of the basal lamina. Furthermore, a dense network of microtubules and microfilaments is described and the functional role of this system in exocytosis is discussed.

Animals↗
PubMed1992

Epithelioid cell histiocytoma. A clinicopathologic and immunohistochemical study of eight cases.

BACKGROUND: Epithelioid cell histiocytomas histologically resemble the intradermal form of Spitz nevus. OBJECTIVE: We have studied eight patients with epithelioid cell histiocytoma. METHODS: In addition to the routine stains, histologic sections were prepared by immunohistochemical techniques for S-100 protein, HMB-45, vimentin, alpha 1-antitrypsin, and common leukocyte antigen. RESULTS: Epithelioid cell histiocytoma is characterized by proliferation of angulated epithelioid cells with abundant eosinophilic cytoplasm. Immunostaining for S-100 protein and HMB-45 were negative. The majority of cells had positive reactions to staining for vimentin and alpha 1-antitrypsin. Approximately 20% to 25% of cells also gave positive reactions to common leukocyte antigen. CONCLUSION: Immunostainings are useful in the differential diagnosis of epithelioid cell histiocytoma from the intradermal form of Spitz nevus.

Adult↗
PubMed1978

Ultrastructural features of epithelioid cell granuloma induced by intradermal injection of xenogeneic nerve tissue.

Epithelioid cell granulomas were induced in rabbits previously sensitised with human sensory peripheral nerve extract by skin testing with homogenate of sural nerve. Ultrastructurally some of the cells contained in their cytoplasm abundant and dilated rough endoplasmic reticulum filled with a moderately dense product while the cytoplasm of other cells contained numerous membrane-bound vesicles. These cells show all the ultrastructural characteristics of epithelioid cells found in human granulomatous disease and in human states of granulomatous hypersensitivity. Thus we have developed an animal model which supports the concept of granulomatous hypersensitivity as a distinct entity in humans to be differentiated from foreign body and delayed-type hypersensitivity reactions. The model may also prove important in elucidating the pathogenesis of granuloma formation in non-lepromatous leprosy and other granulomatous disease and in defining the nature of the products of epithelioid cells.

Animals↗
PubMed1979

Epithelioid cell cultures from rat small intestine. Characterization by morphologic and immunologic criteria.

Rat small intestinal epithelial cell lines have been established in vitro and subcultured serially for periods up to 6 mo. These cells have an epithelioid morphology, grow as monolayers of closely opposed polygonal cells, and during the logarithmic phase of growth have a population doubling time of 19--22 h. Ultrastructural studies revealed the presence of microvilli, tight junctions, an extensive Golgi complex, and the presence of extracellular amorphous material similar in appearance to isolated basement membrane. These cells exhibit a number of features characteristic of normal cells in culture; namely, a normal rat diploid karyotype, strong density inhibition of growth, lack of growth in soft agar, and a low plating efficiency when seeded at low density. They did not produce tumors when injected in syngeneic animals. Immunochemical studies were performed to determine their origin using antisera prepared against rat small intestinal crypt cell plasma membrane, brush border membrane of villus cells and isolated sucrase-isomaltase complex. Antigenic determinants specific for small intestinal epithelial (crypt and villus) cells were demonstrated on the surface of the epithelioid cells, but they lacked immunological determinants specific for differentiated villus cells. An antiserum specifically staining extracellular material surrounding the cells cultured in vitro demonstrated cross-reactivity to basement membrane in rat intestinal frozen sections. It is concluded that the cultured epithelioid cells have features of undifferentiated small intestinal crypt cells.

Animals↗
PubMed1979

Facsimile epithelioid cells obtained from stimulated peritoneal macrophages and their secretory activity in vitro.

Mouse peritoneal macrophages collected after exposure to new born calf serum in vivo were found to have some of the morphological and ultrastructural features attributed to epithelioid cells. These features were accentuated by short term culture in vivo or in vitro. Three accepted varieties of epithelioid cell were reproduced, i.e., those with predominant rough ER, those with predominant smooth vesicles and the plasmacytoid variety. Cells resembling fibroblasts were not seen, nor were lymphoid cells. The facsimile epithelioid cells had considerable secretory activity for a range of macrophage enzymes. They retained the phagocytic capacity and the surface receptors of macrophages but to a reduced extent. It is suggested that epithelioid cells are a form of stimulated macrophage, especially effective in enzyme secretion and liable to appear after excitation of the cell membrane by pinocytosis rather than phagocytosis.

Animals↗
PubMed1979

The differentiation of monocytes into macrophages, epithelioid cells, and multinucleated giant cells in subcutaneous granulomas. I. Fine structure.

The morphological changes occurring in monocytes during their differentiation into macrophages, epithelioid cells, Langhans-type giant cells, and foreign-body-type giant cells were investigated in foreign-body granulomas induced by subcutaneous implantation of pieces of Melinex plastic. Analysis based on Adams's (1974) criteria for discrimination between the several types of cell of the monocyte line, showed that each type has a characteristic type of granule. Primary and secondary granules, numerous in the Golgi area of monocytes were generally found close to the cell membrane and decreased in number in maturing macrophages. This was accompanied by an increase in the number of microtubules. Mature macrophages show numerous characteristic macrophage granules, which are round (average diameter: 280 nm) and have a halo between the limiting membrane and granular matrix. Mature epithelioid cells have characteristic epithelioid cell granules, and multinucleated giant cells a heterogenous population of granules. Fusing macrophages generally have their Golgi areas facing each other, and also show a reduced thickness of the cell coat. The morphology of the multinucleated giant cell is closely related to the number of nuclei present. In Langhans-type giant cells, which generally have two to ten nuclei, a giant centrosphere with numerous aggregated centrioles is found. In transition forms between Langhans-type and foreign-body-type giant cells, which generally contain 10--30 nuclei, the centrioles show less aggregation. In the foreign-body-type giant cells, which generally have more than 30 nuclei, centrioles are virtually absent and never aggregated. These differences between the Langhans-type giant cells, the foreign-body-type giant cells, and the transition forms, support our previous finding that Langhans-type giant cells are the precursors of foreign-body-type giant cells.

Animals↗
PubMed1979

The differentiation of monocytes into macrophages, epithelioid cells, and multinucleated giant cells in subcutaneous granulomas. II. Peroxidatic activity.

The peroxidatic (PO) activity of monocytes differentiating into macrophages, epithelioid cells, and multinucleated giant cells in subcutaneous granulomas was investigated with three different media for the demonstration of PO activity. Irrespective of the stage of differentiation, these cells did not show PO activity in the rough endoplasmic reticulum (RER) or nuclear envelope. In addition, it was found that the morphologically characteristic types of granule of the various cells of the monocyte line (the primary granules and secondary granules of monocytes, the macrophage granules, and the epithelioid cell granules), all have distinct cytochemical characteristics. Monocytes lose their primary and secondary granules during differentiation into mature macrophages. Simultaneously, the granules of both types become elongated and the secondary granule lose their halo. In contrast to monocytes, mature macrophages may contain a few microperoxisomes. During the differentiation of macrophages into epithelioid cells or multinucleated giant cells there is an increase in the number of microperoxisomes.

Animals↗
PubMed1979

Melanoma resembling spindle and epithelioid cell nevus.

Three cases of malignant melanoma resembling spindle and epithelioid cell nevus histologically are presented. Lesions having histologic features of spindle and epithelioid cell nevus (Spitz nevus or juvenile melanoma) at or after puberty should be regarded with caution, particularly when they are heavily melanized. Such lesions are in a histologic "gray zone" and may be malignant.

Adolescent↗
PubMed1992

Three-dimensional study of epithelioid cells by a quick-freezing and deep-etching method in muramyl dipeptide-induced granulomas.

The three-dimensional ultrastructure of epithelioid cells was studied by the quick-freezing and deep-etching (QF-DE), as well as the freeze-substitution (QF-FS) methods. The granulomas were induced in rats by injecting muramyl dipeptide (MDP) into the hind footpads. At 3 weeks after the injection, the footpads were perfused with a fixative, excised, and quickly frozen to prepare the replica membranes. Some unfixed footpads were also quickly frozen and freeze-substituted. Dense networks of intermediate filaments, connected with the nuclei, mitochondria and other vesicular cell organelles, were observed throughout the cytoplasm of epithelioid cells by the QF-DE method. A few actin filaments were located in filopodia and just beneath the cell membranes. Interdigitation of the cell membranes between adjacent cells was clearly demonstrated by the QF-FS method and clathrin-coated pits were identified at the base of interdigitating filopodia. In addition, the exact moment of fusion between endosomes and lysosomes was ascertained by the same method. These results suggest that the cytoskeletal organization of epithelioid cells resembles that of epithelial cells rather than actively motile macrophages.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1992

Macrophage and epithelioid cell nuclear morphology in leprosy.

The spectrum of disease in leprosy is characterised by the presence of macrophages in lepromatous lesions and epithelioid cells in tuberculoid granulomas. Since changes in nuclear shape occur during macrophage activation, we have measured nuclear morphology by planimetry in biopsies across the leprosy spectrum. The results show no significant correlation of any of the parameters of nuclear morphology measured between different lesions or between biopsies from the centre and edge of the same lesion. There were no differences between the Ridley-Jopling groups. However, several parameters which measure the degree of ellipticity of the nuclei showed strong correlation with granuloma size in untreated leprosy patients. This suggests that local pressure effects may influence epithelioid cell and macrophage nuclear morphology in leprosy lesions.

Adult↗
PubMed1976

Immunological and non-immunological phagocytosis by inflammatory macrophages, epithelioid cells and macrophage polykaryons from foreign body granulomata.

Inflammatory macrophages, epithelioid cells and macrophage polykaryons were obtained on the surface of round glass coverslips inserted into the subcutaneous tissue of mice and removed at different intervals. About 90 per cent of the macrophages and polykaryons express IgG, C and non-specific surface receptors, involved in phagocytosis, up to 15 days after coverslip implantation. In 21-day-old lesions, about 50 per cent of these cells lose the IgG resed with IgM and complement but do not incorporate these particles and are poorly phagocytic for glutaraldehyde-treated horse red blood cells. The ultrastructural study of these cells demonstrates that they are macrophages which have undergone epithelioid transformation. Whole-body irradiation of mice bearing implanted coverslips of 7 days duration reveals that 6 days after irradiation, the great majority of macrophages and multinucleate cells have acquired epithelioid characteristics. It is suggested that the loss of immunological receptors during epithelioid transformation in granulomas may protect bacteria and be disadvantageous to the host.

Age Factors↗
PubMedDate not supplied

Alpha-naphthyl acetate esterase-1 (ANAE-1) secreted by epithelioid cells from induced rabbit lung granuloma showed MIF activity.

The function of alpha-naphthyl acetate esterase-1, whose isoelectric point values range from 5.15 to 5.45, was examined. A higher value of alpha-naphthyl acetate esterase-1 was detected in the extracts of epithelioid cells isolated from rabbit lung granuloma at 4 weeks after injection of Freund's complete adjuvant, compared to those values of alveolar macrophages isolated from the same lungs described above and of the normal lungs. Additionally, this enzyme activity was observed to be prominent in the culture supernatants of epithelioid cells. alpha-Naphthyl acetate esterase-1 was purified from lung granuloma as a single 62-kDa band by SDS-PAGE analysis. The purified enzyme showed a macrophage migration inhibition activity at concentrations over 20 nM, and its activity was dose-dependent. Moreover, when various amounts of the purified enzyme were added to lymphocyte-derived macrophage migration inhibitory factor, macrophage migration inhibition was significantly enhanced with a dose-dependent manner. The results suggest that alpha-naphthyl acetate esterase-1 secreted by granuloma macrophages, particularly by epithelioid cells, contributes to granuloma formation.

Animals↗
PubMed1979

Epithelioid cell granulomata in the mucosa of the small intestine in Whipple's disease.

This report is the first description of sarcoid-like epithelioid cell granulomata in the mucosa of the small intestine in a case of Whipple's disease. The epithelioid cells do not contain PAS-positive material or products of bacterial degradation. Their ultrastructural features characterize them as histiocytes which have become secretory rather than phagocytic. These sarcoid-like lesions are considered to be a morphological manifestation of an immunological process in Whipple's disease and not to represent evidence of sarcoidosis as a concomitant or associated disorder.

Granuloma↗
PubMed1976

[Coincidence of Hodgkin's disease and epithelioid-cell granulomatosis in liver and spleen].

Two of seventy patients with Hodgkin's disease who had exploratory laparotomy with liver biopsy and splenectomy were found to have extensive epithelioid-cell granulomas in liver and spleen. The coincidence of malignant tumour and epithelioid-cell granulomas of liver and spleen without lymph-node involvement is unusual. Knowing of the coincidence of Hodgkin's disease and such granulomas is clinically important because extensive diagnostic measures, including biopsy, are necessary in the differential diagnosis, and the patient's prognosis will depend on the therapeutic measures taken.

Adult↗
PubMed1978

Ultrastructural observations on epithelioid cell granulomas induced by zirconium in the guinea-pig.

An ultrastructural study has been made of the allergic-type nodular granulomas that can be induced in guinea-pigs sensitised to sodium zirconium lactate. Lesions taken at the peak of granuloma development 7 days after skin testing contained epithelioid cells which could be recognised particularly by their content of rough endoplasmic reticulum, fimbriated cell membrane and typical nuclear appearance. Multinucleate giant cells were also seen. These cells were characterised by their large number of lysosome-like dense bodies and phagocytic structures. Both epithelioid cells and multinucleate giant cells were similar to those described in zirconium granulomas in man. However, these cells differed in a number of respects from similar cells observed in human sarcoidosis. A constant feature of the guinea-pig lesions was the presence of large numbers of apparently active fibroblasts.

Animals↗
PubMed1975

[Epithelioid cell. Ultrastructural data during various pathological conditions].

A morphological study permitted us to show that the epithelioid cell is an active cell, the characteristic vesicles of which seem to be linked to the presence of a glycoprotein substance which passes through the Golgi apparatus and becomes accumlated in the lysosomes owing to their richness in acid phosphatase. A fraction of this substance may be secreted into the extra-cellular medium, without it being possible to determine its precise nature and whether this function is carried out only by this cell.

Connective Tissue↗