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Query: UMLS:C0007097 (carcinoma)
 152,788 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The calcified keratin in the horn pearls of a glans carcinoma has been studied by histochemical and ultrastructural methods. The former have shown that the calcified areas contain glycoproteins and acid proteoglycans and have a concentration of sulphydryl groups greater than that of the surrounding, uncalcified keratin. Electron microscopy has shown the presence of intracellular needle- and filament-like crystals closely related to the keratinocyte filaments and similar to those found in other calcified tissues. Besides the close relationship discovered between crystals and keratinocyte filaments, the other main conclusions are that keratin calcification is an intracellular process and that keratin molecules are responsible for the induction and regulation of the process.
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PMID:Histochemical and electron microscopical investigations on the calcified keratin in the horn pearls of a glans carcinoma (calcified keratin). 9 64

Material from a nasopharyngeal carcinoma (NCP) has been passaged in athymic (nude) mice to eliminate non-malignant infiltrating cells. The human origin and derivation from NPC malignant epithelial cells of the nude mouse tumours have been confirmed by chromosome examination, electron microscopy showing desmosomes and keratin fibrils, and postive EB virus nuclear antigen (EBNA) testing. Samples of the mouse-grown tumours were cultured and pure monolayers of epithelial cells were obtained which still expressed EBNA and contained desmosomes and keratin; these cultures grew well for about 3 weeks. Extensive electron microscope searches failed to reveal herpes virus particles. In contrast, cultures treated with BUdR showed typical immature and mature herpes virus particles in epithelial, keratin-containing cells, and immunofluorescence tests for virus capsid antigen with a battery of human sera identified this agent as EB virus. EB virus has thus, for the first time, been activated in NPC epithelial cells and shown to be capable of replication in a cell type other than a primate B-lymphocyte.
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PMID:Activation in vitro by BUdR of a productive EB virus infection in the epithelial cells of nasopharyngeal carcinoma. 17 12

An adult male African green monkey (Cercopithecus aethiops) with an undifferentiated carcinoma, probably originating from the nasal mucosa, was received from the Akron, Ohio zoo. Cultivation of this tumor in vitro resulted in a mixture of fibroblastic and epithelial cells which was subsequently separated using differential trypsinization. The neoplastic nature of the cultured epithelial cells was verified by their ability to transplant into athymic nude, or antithymocyte serum-treated mice, where poorly differentiated carcinomas were produced, and cultures of the tumors that arose in nude mice were morphologically similar to pretransplantation cultures. Early cultures showed a normal male karyotype characteristic of the species; however, in long-term cultures, a clearly defined, small submetacentric Y chromosome was not observed. Electron microscopic examination of tumor tissue and cultured tumor cells revealed desmosomes and the presence of cytoplasmic (keratin-type) fibrils, which tended to be organized around the nucleus. In addition to the keratin-type fibrils, the cultured tumor cells also contained a large amount of cytoplasmic inclusion material that may represent keratohyalin granules. There was no evidence of a viral association with tumor material or cultured cells. The cultures were susceptible to infection by vesicular stomatitis virus, Herpesvirus hominis type 1, and H. saimiri, but were resistant to the Epstein-Barr virus.
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PMID:Characterization of a spontaneous undifferentiated carcinoma from an African green monkey (Cercopithecus aethiops). 18 33

Electron microscopy examination of nasopharyngeal carcinoma grafts in nude mice showed that the tumor cells retained their epithelial characteristics, as betrayed by the presence of keratin fibrils and of functional complexes at the cell membrane. Thus the cells positive for Epstein-Barr virus-specific nuclear antigen present in such grafts do represent the progeny of human epithelial tumor cells. C-type virus particles were observed in one tumor graft, indicating that epithelial human cells could pick up a mouse virus.
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PMID:Epithelial characteristics of tumor cells in nasophasyngeal carcinoma. 18 91

Explants of fresh biopsy specimens from non-neoplastic nasopharyngeal (NP) mucosa, nasopharyngeal carcinoma (NPC), other tumours (OT) of the head and neck and freshly removed tonsils were treated with an Epstein-Barr virus (EBV) preparation from B95-8 cells and cultured. The mainly epitheloid outgrowths from these infected explants were then compared with those from their respective uninfected controls at 14 days. Growth stimulation occurred with a significantly higher frequency, and the degree of stimulation was generally higher with the infected NP explants than those of the similarly infected explants of other origins. Furthermore, after treatment with the virus preparation, several of the outgrowths from the NP explants showed growth characteristics and cellular morphology typical of those of transformed cells. Light microscopy has shown the changed NP cells to have epithelial characteristics. This is now being verified by electron microscopy, which has so far shown the presence of keratin fibrils and desmosomes in one specimen examined. They are also being examined for the presence of EBV-DNA and EBNA, and other features of transformation, including malignant tendency, by passage through athymic nude mice.
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PMID:Possible transformation of nasopharyngeal epithelial cells in culture with Epstein-Barr virus from B95-8 cells. 19 48

Nonglandular carcinomas of the nasopharynx originate in the epithelium of that anatomical region. Although numerous morphological patterns exist at the level observable by light microscopy, ultrastructurally, all have features of squamous-cell carcinoma. The most useful and consistent classification on the basis of light microscopy is that which separates keratinizing squamous carcinomas from nonkeratinizing carcinomas. Approximately 25% of tumours have abundant and easily recognized keratin. The nonkeratinizing types are more confusing, since many variants exist, both from tumour to tumour and, frequently, within the same tumour. Variable tissue reactions to infiltrating tumours, ranging from marked desmoplasia to complete absence of reaction, add to the confusion. The descriptive names applied to the variants of nonkeratinizing squamous carcinomas are well engraved in medical communications, and there is little chance that they will be abandoned.
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PMID:The histopathological spectrum of nasopharyngeal carcinoma. 73 Jan 99

The Nara Bladder Tumor No. 2 cell line, established from a urinary bladder carcinoma in the Wistar rat, formed keratinizing cells and multicellular pearls in meniscus gradient culture when fed with a medium of 15 or 30% fetal calf serum in Eagle's minimal essential medium. Confluent monolayer cultures were first prepared with the tubes in conventional horizontal position. When cultures were then changed to a vertical position, stratification, piling up, and aggregation of cells were observed in a few days at the aerobic end of the gradient. Keratinization appeared 1 week after the tubes were placed in vertical position. Squamous differentiation proceeded to the formation of keratin pearls, a phenomenon never observed so distinctly and in such abundance in horizontal culture. Supplements of vitamin A, as low as 1 IU/ml, added to the medium did not inhibit piling up or aggregation but did prevent keratinization. Inhibition of keratinization by vitamin A was reversible. After vitamin A was removed from the medium, the cells in the aggregates progressed to keratinization.
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PMID:Vitamin A inhibition of keratinization in rat urinary bladder cancer cell line Nara Bladder Tumor No. 2 in meniscus gradient culture. 109 79

Chronic ulcers of the rat colon were produced by a administering a 3 per cent. hydrogen peroxide enema. Twenty-three per cent. of the animals with chronic ulcers had areas of squamous metaplasia at the wound margins which in some cases covered the defect. Electron microscopy revealed some areas similar to epidermis with the four characteristic cell layers. The cells demonstrated many filaments, membrane-coated granules, keratohyalin granules and keratin. The cells were linked by complex of cytoplasmic bridges and frequent desmosomes. Basal cells often displayed large irregular nuclei with double nucleoli. Other areas demonstrated a grossly irregular surface with marked cellular pleomorphism and defects in the basement lamina. The incidence of squamous metaplasia and squamous-cell carcinoma in the colon of man is discussed. The ultrastructural characteristics of squamous metaplasia in the trachea and bronchi is recorded and compared with those of the colon. It is suggested that as neoplasia has been observed to follow experimental metaplastic lesions in the bronchus, a similar ocurrence could take place in the colon as the squamous cells exhibited similar characteristics.
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PMID:Squamous metaplasia in the healing of chronic colonic ulcers of the rat. 119 58

In a systematic study of bladders from consecutively cystectomized patients, 40 primary urinary bladder carcinomas were examined with regard to the type of differentiation. Metaplastic areas were found in 24 of the tumours. A positive reaction of keratin to Kreybergs stain was required for the definition squamous metaplasia. Squamous areas were found in 16 of the tumours. In 4 tumours there was, in addition to squamos metaplasia, glandular metaplasia which was defined as definite glandular tissue with dysplasia of the epithelium. In 4 tumours, glandular metaplasia was also present in addition to the urothelial carcinoma. In 18 cases, metaplastic changes were present in the luminal portion of the tumour from which the biopsy material and desquaminated material originated. The occurrence of metaplasia was related to the degree of differentiation of the urothelial part of the tumour. Metaplastic changes were most frequent in the poorly differentiated tumours. The biopsies obtained pre-operatively permitted of the diagnosis metaplasia being made in 15 cases, while the cytological material suggested metaplastic changes in 4 cases only. The biological function of metaplasia is unknow. The possibility that these areas will react differently to radiation and chemotherapy is present and the frequency of such changes would suggest that their importance should be studied by their registration as mixed forms as stated by WHO.
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PMID:Types of metaplasia in forty urothelial bladder carcinomas. A systematic histological investigation. 125 42

An unusual coexpression of glial fibrillary acid protein (GFAP), keratin and vimentin occurs in pleomorphic adenoma of salivary gland. We designed this study to see if coexpression of the markers was also present in monomorphic adenoma of the salivary gland and whether monomorphic adenoma could be distinguished from other salivary gland tumours by marker studies. Immunocytochemical markers were used on fine needle aspiration samples from four cases of monomorphic adenoma, two cases of oncocytic adenoma, three cases of adenoid cystic carcinoma and four cases of pleomorphic adenoma. While positivity for cytokeratin, vimentin and S-100 was consistently found in all cases of monomorphic adenoma, only cytokeratin was expressed in adenoid cystic carcinoma. In pleomorphic adenoma, GFAP, cytokeratin and vimentin were coexpressed while in cases of oncocytic adenoma none of the markers was localized. Thus, it appears that by using a combination of GFAP, cytokeratin, vimentin and S-100 a distinction between these neoplasms may be possible. However, a larger study is needed to establish the usefulness of this approach.
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PMID:Coexpression of vimentin, cytokeratin and S-100 in monomorphic adenoma of salivary gland; value of marker studies in the differential diagnosis of salivary gland tumours. 128 26


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