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Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Two tumors induced by BK virus in hamsters of an inbred strain were serially transplanted by subcutaneous injection of tumor explants. Both the original tumors as well as the transplants grew as solid, localized, encapsulated tumors. Histologically tumors were classified as fusocellular fibrosarcomas. Polymorphic tumor tissue was by an abundance of collagen fibers and multinucleated giant cells. Cell lines established from tumors contained nuclear T antigen which stained with sera from a number of tumor-carrying hamsters, but also with SV40 T antiserum. Viron antigens were not detected in these cell lines, and no virus was isolated when tumor extracts were inoculated in Vero cells.
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PMID:Transplantable hamster tumors induced with the BK virus. 16 31

Ultrastructural features were correlated with a series of special staining reactions in eight cases of bronchiolo-alveolar carcinoma. Ultrastructural, all tumors were similarly composed of large cells with abundant cytoplasm and small nuclei in close contact with each other. Straight membranes or complex interdigitations occurred within adjacent tumor cells, attached to each other by scattered desmosomes. Microvilli or cilia abutted from free surfaces of the cells, and were noted in different stages of evolution. Numerous organelles were seen in the cytoplasm, including prominent mitochondria and single or coalescent secretory vacuoles with granular matrix resembling mucin. Other cytosomes less commonly found were irregular, partially lamellated inclusions and dark, homogeneous structures without limiting membranes. The stroma of the tumors was rich in elastin and collagen. Both the number of secretory vacuoles in the cytoplasm of tumor cells and the amount of connective tissue fibrils in the stroma of the tumors correlated well with the findings in the series of special staining reactions. No definite ultrastructural feature was present to identify the tumors as orginating from Type II alveolar epithelial cells, but the possibility exists that they arose in the bronchiole, from undifferentiated basal cells or mucinous cells per se. Our impression in these eight cases studied is consistent with the view that bronchiolo-alveolar carcinomas are indistinguishable at the ultrastructural level from other bronchogenic adenocarcinomas.
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PMID:Ultrastructure of human bronchiolo-alveolar cell carcinoma. 16 87

A case of mixed hepatoblastoma with osteoid elements was studied by light and electron microscopy. The ultrastructure of the epithelial elements showed a lack of differentiation and simple cytoplasmic organelles. However, an occasional cytoplasmic crystalloid structure were seen. The ultrastructure of the osteoid foci showed fibroblast-like cells capable of collagen formation, clearly distinguishable from the epithelial elements. These cells had neoplastic characteristics of nuclear pleomorphism and high nucleo-cytoplasmic ratio. These findings support the belief that hepatoblastoma arises from a multipotential blastema capable of both epithelial and mesenchymal differentiation, with the osteoid elements being an intrinsic neoplastic component of the tumor.
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PMID:An ultrastructural study of mixed hepatoblastoma with osteoid elements. 16 88

This study presents the results of light-microscopic, histochemical, and electron-microscopic investigations of dense (inclusion) bodies in a recurring digital fibrous tumor of childhood. At ultrastructural level it was possible to observe several stages of development correlated with changes of ergastoplasmic reticulum. The viral nature of these bodies was refuted and the conclusion was drawn that their formation is associated with a disturbed intracellular metabolism. The defective intracellular transport of collagen precursors followed by abnormal deposition of collagenous proteins, which are also to some extent abnormally aggregated, could be of special importance.
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PMID:Morphogenesis of intracytoplasmic dense (inclusion) bodies in a recurring digital fibrous tumor of childhood. Light- and electron-microscopic investigations. 17 Jul 30

A case of an intracranial germinoma from the suprasellar region of a 9-year-old girl was examined in the electron microscope. The tumor consists, for the most part, of both large polygonal and small lymphocyte-like elements. Annulate lamellae are common in the epithelial cells. The small blood vessels are fenestrated, and the endothelial cells contain tubular bodies, membrane-bounded vacuoles containing dense fluid and occasional tubules, arrays of tubules within the nuclear envelope and rough endoplasmic reticulum, and a markedly irregular luminal surface. Dense, lamellated structures are present in the widened, collagen-containing perivascular spaces.
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PMID:Some new observations in an intracranial germinoma. 17 Jul 74

Collagenase cleavage of human Type II and III collagens has been studied using a highly purified preparation of rabbit tumor collagenase. Progress of the reactions in solution was followed by viscometry and the results indicated that under the conditions employed Type III collagen molecules were cleaved at approximately five times the rate of Type II molecules. Cleavage products of the reactions were isolated in denatured form by agarose molecular sieve chromatography. The molecular weights and amino acid compositions of the products demonstrated that Type II and III molecules had been cleaved at the characteristic three-quarter, one-quarter locus, giving rise to a large fragment derived from the NH2-terminal portion of the molecule and a smaller fragment representing the COOH-terminal region. The amino acid sequence at the NH2-terminal portion of the smaller fragment derived from Type II collagen was determined to be Ile-Ala-Gly-Gln-Arg, and the corresponding region from Type III collagen was found to have the sequence Leu-Ala Gly-Leu-Arg. These sequences for alpha1(II) and alpha1(III) chains adjacent to the site of collagenase cleavage along with previous data for alpha1(I) and alpha2 chains indicate that the minimum specific sequence required for collagenase cleavage is Gly-Ile-Ala or Gly-Leu-Ala. Inspection of the available sequence data for collagen alpha chains indicates that the latter sequences are found in at least three additional locations at which collagenase cleavage does not occur. Each of the sequences which are apparently not substrates for collagenase, however, are followed by a Gly-X-Hyp sequence. We suggest, then, that a minimum of five residues in collagen alpha chains COOH-terminal to the cleavage site comprise the substrate recognition site.
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PMID:Cleavage of Type II and III collagens with mammalian collagenase: site of cleavage and primary structure at the NH2-terminal portion of the smaller fragment released from both collagens. 17 19

A stable cell line (MCF-7), derived from a pleural effusion of a patient with metastatic breast carcinoma, was maintained in these laboratories for more than 3 years in conventional monolayer culture. To further characterize the tumor origin of the MCF-7 line, cells were grown on collagen-coated cellulos sponges. On the three-dimensional sponge matrix, the cells formed clusters, ductlike structures, and lumina similar to the patterns observed in the antecedent primary tumor and in the pleural metastasis. The similarity between the original tumor and the cells grown in sponge suggested that the MCF-7 cells did in fact retain the potential to express the histologic patterns of tumor, even in the absence of stroma support. This study confirmed the utility of sponge culture for the investigation of the retention of tumor characteristics by cultured cells of neoplastic origin.
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PMID:Reexpression of the original tumor pattern by a human breast carcinoma cell line (MCF-7) in sponge culture. 17 83

The light microscopic and ultrastructural features of five asymptomatic peripheral carcinoids presented as distinct pulmonary solitary nodules are described. By conventional microscopy the tumors displayed a variety of histologic patterns, the most unusual one showing tumor cells embedded in a richly vascular hyalinized stroma and forming papillary structures or cystic spaces lined by low cuboidal cells which ultrastructurally bore a strong resemblance to intermediate or transitional forms between types I and II pneumocytes. A striking feature of these tumors was their rich vasculature associated with a marked perivascular sclerosis composed of basement membrane-like material and collagen fibrils most likely produced by the increased numbers of pericytes surrounding these sclerotic vessels. The clinical implications, biologic behavior, and association of these tumors with other pulmonary neoplasms are also discussed.
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PMID:Peripheral pulmonary carcinoid tumors. 17 84

In order to demonstrate a collagenolytic enzyme in a tumor, solid Tawa sarcoma was subjected to a tissue culture technique. Salt- and acid-soluble collagen used as substrate was extracted from the rat skin and tail tendon. The tumor mass used was obtained on the 5th, 8th, and 11th days after subcutaneous transplantation of ascites Tawa sarcoma cells. Each tissue fragment in the inner and outer layers of the tumor mass was incubated on collagen gel at 37 degrees for 4 days, and collagenolytic activity was determined by comparing the relative content of hydroxyproline in the attacked collagen which was separated by means of centrifugation. All fragments were found to possess collagenolytic activity with some variation. Higher activity was observed in the outer layer than in the inner layer. Tumor fragments were cultured, and the collagenolytic enzyme was isolated from the culture medium and concentrated by ammonium sulfate precipitation and acrylamide disc electrophoresis. Collagenolytic enzyme activity was examined for its mode of attack on native collagen.
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PMID:Collagenolytic enzyme in solid Tawa sarcoma. 17 66

The congenital mesoblastic nephroma is a distinct tumor entity, which should be clearly distinguished from Wilmus-tumor. The pure mesenchymal tumor is usually present at birth and palpated as a mass in the kidney. Macroscopically the tumor reveals a striking resemblance with an uterine fibroid. Histologically the tumor tissue ist characterized by 1. interlacing bundels of spindle cells with uniform cell nuclei and regular mitotic figures, 2. collagen fibres between the tumor cells, 3. an angiomatous marginal zone, no tumor capsule, 4. hematopoetic foci and dysplastic glomeruli and tubuli in areas where normal kidney parenchyma mixes with tumor tissue, 5. small myxomatous areas within in the tumor, 6. no invasion of blood vessels or pelvis. Prognosis of the congenital mesoblastic nephroma is much better than in Wilms-tumor. Metastases have not been described so far. If, however, the tumor tissue is incompletly removed during operation, the neoplasm may recur and prove fatal. Ultrastructural and DNA cytophotometric studies suggests a low grade malignancy rather than a truely benign behaviour of this tumor.
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PMID:[Congenital mesoblastic nephroma - a semimalignant fibroleiomyomatous kidney tumor of the newborn (author's transl)]. 18 64


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