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

An unusual foreign body reaction to silica (quartz), resembling fibrous histiocytoma, is described in 7 patients (age range 22 to 71 years). These lesions occurred in the inguinal region (4 cases) or the abdominal wall (3 cases), and in 5 instances were associated with a history of injection at the same site 10 to 41 years previously. Most commonly the injection consisted of the administration of a sclerosing agent for the repair of a hernia. Microscopically these lesions contained broad sheets of histiocytes separated by bands or concentrically lamellated nodules of collagen. Intra- and extra-cellular birefringent crystals, identified by x-ray diffraction as silica (quartz), were present in all cases and served to distinguish this process from a true neoplasm. Although the injection therapy for hernia is now obsolete, it was formerly practiced in the United States with a variety of sclerosing agents including silica (quartz). Since these lesions are often confused with a benign or malignant fibrous histiocytoma it is recommended that fibro-histiocytic lesions associated with a previous hernia or injection at the same site be examined for the presence of silica.
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PMID:Silica reaction simulating fibrous histiocytoma. 21 95

Three human malignant melanomas were cultured in pure populations and one tumor was cloned into melanotic and amelanotic cell lines. In the homogenates of these cultured cells, specific collagenase activities were demonstrated by isotope release from 14C-labeled collagen, disc electrophoresis, and specific cleavage of collagen molecules as demonstrated in the segment long spacing form. No significant collagenase activity was observed in the culture media. Interestingly, early cultures had a high collagenase activity in the cells and as they were successively subcultured, the activity diminished. Cysteine completely inhibited the degradation of tropocollagen as determined by disc electrophoresis and EDTA partially inhibited the degradation. It is concluded that human malignant melanoma cells produce a specific collagenase in vitro which can be extracted in early culture directly from the homogenate.
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PMID:Collagenolytic activities of cultured human malignant melanoma cells. 21 92

Antibodies to fibronectin and to distinct types of procollagens and collagens were used in immunofluorescent staining to localize these proteins in cell cultures. Normal human skin or lung fibroblasts produced a fibrillar pericellular matrix in which fibronectin and procollagen (types I and III) showed extensive codistribution. Fibronectin and procollagen were synthesized by the same cells as judged by double-stain immunofluorescence. Pericellular procollagen was specifically digested with collagenase without an effect on the fibrillar distribution of matrix fibronectin. Brief treatment with trypsin removed both matrix proteins. The human tumor cell lines HT-1080 (fibrosarcoma) and RD (rhabdomyosarcoma) produced little or no matrix fibronectin or procollagen. At sites of cell contact, simian virus 40-transformed lung fibroblasts (VA13) produced small amounts of pericellular fibrillar matrix fibronectin that codistributed with procollagen type I. Intracellular fibronectin and procollagen were visualized in all of these human sarcoma cell lines. When chicken embryo fibroblasts infected with a T class mutant (NY68) of Rous sarcoma virus temperature-sensitive for transformation were maintained at the nonpermissive temperature (41 degrees ) the cells had normal phenotype and a fibrillar matrix containing fibronectin and procollagen was present. At the permissive temperature (35 degrees ), the cells showed transformed phenotype and the matrix was lost. The failure to produce a pericellular fibronectin/collagen matrix may account for several phenotypic characteristics of transformed cultured fibroblasts.
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PMID:Codistribution of pericellular matrix proteins in cultured fibroblasts and loss in transformation: fibronectin and procollagen. 21 6

The effect of the potent tumor promoter phorbol 12-myristate 13-acetate (PMA) on collagen synthesis, a differentiated property of chick embryo fibroblasts, was examined. Collagen synthesis, as measured by the rate of formation of [3H]hydroxyproline from [3H]proline, was found to be decreased in cells treated with PMA but not in cells treated with the parent alcohol phorbol. The decrease in collagenase-sensitive proteins was confirmed by polyacrylamide gel electrophoresis of cell lysates, indicating that the decrease could not be ascribed simply to an effect on prolyl hydroxylase. Although a decrease in collagen synthesis was observed after one day, five days were required for a maximal reduction to 20% of that of dimethyl sulfoxide-treated controls. The effect of PMA on collagen synthesis was reversible. It was therefore not the result of a permanent transformation of the cells or of the selection of a population of cells with a reduced capacity for collagen synthesis. Collagen synthesis was decreased in chick embryo fibroblasts transformed by Rous sarcoma virus. Treatment of these cells with PMA for 5 days brought about a further decrease to 50% of the level in dimethyl sulfoxide-treated transformed controls.
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PMID:Decrease in collagen production in normal and Rous sarcoma virus-transformed chick embryo fibroblasts induced by phorbol myristate acetate. 21 32

The specificity of human skin collagenase and of an enzyme from an invasive tumor were studied by using types I, II, III, IV, and V (AB) collagen as substrates. Human skin collagenase degraded types I, II, and III collagen, producing the characteristic 3/4 and 1/4 cleavage products, but failed to degrade type IV or V collagen. Collagenase prepared from the invasive tumors showed maximal activity after trypsin treatment. The tumor enzyme degraded type IV (basement membrane) collagen, producing fragments consistent with a single cleavage site but did not attack types I, II, III, and V collagen. Because type IV collagen prepared by pepsinization of placenta was also digested, it is likely that cleavage of type IV collagen by the tumor collagenase occurs within a largely helical domain. A type IV collagenase could play a significant role in tumor metastases and in normal tissues where basement membrane turnover takes place.
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PMID:Preferential digestion of basement membrane collagen by an enzyme derived from a metastatic murine tumor. 22 20

Angiofibromas from two patients with tuberous sclerosis were studied by light and electron microscopy. Light microscopy revealed that these tumor-like nodules (which in the past have been called adenoma sebaceum) were made up of dilated capillaries, venules and arterioles embedded in connective tissue. At the ultrastructural level the arterioles embedded in connective tissue. At the ultrastructural level the endothelium of these vessels showed large numbers of microvilli on their luminal surface. The stroma contained many banded structures (so-called fibrous long spacing collagen). Myofibroblasts recently described in juvenile nasopharyngeal angiofibromas were not found in these angiofibromas of tuberous sclerosis.
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PMID:Angiofibromas in tuberous sclerosis: a light and electron microscopic study. 22 82

Fibroblast cultures derived from human basal cell carcinomas demonstrated an increased capacity to synthesize and secrete collagenase. Although the levels of collagenase were up to 8-fold greater than those of normal control cell lines, this phenotypic trait was not permanent and was expressed only for a few passages following primary explanation. The basal cell carcinoma fibroblast collagenase was secreted as a proenzyme. The kinetics of activation and the catalytic efficiency of the basal cell carcinoma fibroblast enzyme were equal to control collagenase, indicating that increased activity was due to increased synthesis of enzyme protein. Increased synthesis of collagenase was not due either to altered cell growth or to an overall increase in protein synthesis. Furthermore, synthesis of another major protein, of another major protein, collagen, was not enhanced. The data suggest that the tumors may have stimulated adjacent fibroblasts to produce more collagenase which is of importance in tumor invasion.
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PMID:Enhanced collagenase production by fibroblasts derived from human basal cell carcinomas. 22 89

Malignant fibrous histiocytomas are well-described tumors of the soft tissues. Recent investigations have shown that malignant histiocytoma may also occur as a primary bone tumor. However, difficulties may arise to distinguish malignant histiocytoma of bone from other malignant bone tumors, such as osteosarcoma. In the present study, the ultrastructure of five cases of malignant fibrous histiocytoma of bone is compared with that of osteosarcoma. The results show that malignant fibrous histiocytoma is composed mainly of histiocytic cells and fibroblastic cells. In addition, xanthomatous cells, undifferentiated cells, and giant cells may be observed. By contrast, the predominant cell type in osteosarcoma is the neoplastic osteoblast, characterized by abundant rough endoplasmic reticulum. Signs of matrix calcification in the intercellular matrix between the collagen fibrils are regularly observed in osteosarcoma, but not in malignant histiocytoma. From these results it is concluded that the ultrastructure of malignant fibrous histiocytoma arising in bone is morphologically identical with the soft tissue counterpart of this tumor. The components of the tumor are derived from neoplastic histiocytes. This cytogenesis differs from that of osteosarcoma, which is derived from neoplastic osteoblasts. Therefore, from the ultrastructural point of view, malignant fibrous histiocytoma of bone should be accepted as a distinct histologic entity among bone tumors.
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PMID:Malignant fibrous histiocytoma of bone and osteosarcoma. A comparative light and electron microscopic study. 22 75

Osteosarcomas formed in antilymphocyte serum (ALS)-treated hamsters when 2x10(6) TE-85 human osteosarcoma cells (maintained in tissue culture) infected with M-MSV (RD-114) virus were injected adjacent to the femur or the scapula; undifferentiated sarcomas formed when 1 x 10(6) cells were injected subcutaneously. Tumors were palpable 10 to 14 days after the cells were injected and grew progressively until the animals died (mean survival time was 30 days). All animals had pulmonary metastases. Neither the subcutaneous sarcomas nor the metastases contained bone or osteoid; however, the osteosarcomas adjacent ot the femur and scapula contained collagen, osteoid and calcified bone when observed by light and electron microscopy. These results indicate that the TE-85-M-MSV cell-ALS hamster system is an animal model for the study of osteosarcomas of human cell origin.
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PMID:An animal model for human osteosarcoma. 26 8

Electron microscopic study of 9 osteosarcomas corroborates the light microscopic observation that cells with osteoblastic, chondroblastic and fibroblastic features occur in osteosarcomas. Two types of multinucleated giant cells were observed, one was osteoclast-like. The other had anaplastic and degenerative changes. The intercellular matrix is composed of collagen fibers, amorphous ground substance with osteoid and tumor bone. Contrary to many previous electron microscopic reports, osteosarcomas contain more than one cell type.
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PMID:The ultrastructure of human osteosarcoma: a study of nine cases. 27 14


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