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

The quantitative changes of glycosaminoglycans in tumor tissue of human lung cancers (6 squamous cell carcinomas, 7 small cell carcinomas and 10 adenocarcinomas) were studied. Normal lung tissues contained of 3.38 mumol uronic acid/g dry weight glycosaminoglycans which consisted of hyaluronic acid, chondroitin sulfates, dermatan sulfate and heparan sulfate. The total amount of glycosaminoglycans in human lung cancer tissues increased 1.7 to 3.5 times in comparison with that in normal lung tissues. The increase in tissue content of glycosaminoglycans was accompanied by an increase in the chondroitin sulfate level in every histologic type of lung cancer, as well as marked increase in hyaluronic acid level in squamous cell carcinomas, and a moderate increase in small cell carcinomas. The concentrations of dermatan sulfate and heparan sulfate in lung cancer tissues did not show any significant changes compared with those in normal lung tissues. The increase in total amount and changes in the composition of glycosaminoglycans in human lung cancer tissue were closely related to the histologic type of the tumor. In adenocarcinomas, some acid glycoprotein with sialic acid was simultaneously detected during the separating course of glycosaminoglycans, which was considered to be derived from mucinous substances related to adenocarcinoma cells.
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PMID:[Glycosaminoglycans in human normal lung tissues and lung cancer tissues]. 229 Feb 28

Many glioma-derived cell lines have the capability of escaping cell-mediated immune attack. One mechanism of escape is the secretion of a hyaluronidase-sensitive mucopolysaccharide coat by these cells. This coat prevents contact and tumor cell killing by specific cytolytic allogeneic lymphocytes. The production of the coat by the tumor cells is stimulated by a macromolecular factor released by peripheral blood mononuclear (PBMC) cells in culture. We have examined the morphologic and ultrastructural features of this extracellular matrix. Three coat-producing lines were studied. Under phase contrast light microscopy, the coat is a clear pericellular 'halo'. To stain this zone, ruthenium red and Alcian Blue 8 G stains, which bind to acid mucopolysaccharides (to a large extent, hyaluronic acid), were used. The two stains produced similar results. With light microscopy, a weblike pattern of stain was evident throughout the halo region. With transmission electron microscopy, staining was found along the plasma membrane of the glioma cells and their microvilli, stretching in long, branching filaments from these surfaces and, in some instances, from one microvillus to the next. Since mucopolysaccharide matrices have a large aqueous component, it was necessary to determine whether dehydration alters the stain pattern. Therefore, undehydrated ruthenium red stained specimens from each culture were embedded in Quetal 651 (Ted Pella, Inc., Tustin, CA), a water soluble plastic. No morphologic differences were noted between the hydrated and dehydrated specimens. This study indicates that numerous long microvilli and a secreted mucopolysaccharide matrix are important structural elements of the lymphocyte-stimulated tumor cell halo in vitro. The mechanism by which the PBMC factor stimulates coat formation and the importance of the coat in in vivo tumor defenses remain to be elucidated.
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PMID:Ultrastructural features of the lymphocyte-stimulated halos produced by human glioma-derived cells in vitro. 242 Sep 43

A hyaluronidase-sensitive component of human peritoneal fluid from a patient with Wilms' tumor when injected into rabbits has been shown to suppress the formation of humoral precipitating antibodies to certain major classes of proteins present in the fluid. Furthermore, it has been found that hyaluronic acid, when included with certain test antigens (serum albumin, fetuin) or antigen mixtures (tumor isolates or mixtures of albumin, immunoglobulin G and immunoglobulin M), produces a marked distortion or complete blockage of immunoelectrophoresis precipitin arcs, as well as altered gel chromatography elution profiles. These findings that hyaluronic acid can interfere profoundly with both the elicitation of a complete antibody response and the formation of "normal" patterns of antigen-antibody precipitates in laboratory tests supports the possibility that this polysaccharide may play an immuno-regulatory role by masking potential immunogens. Consideration of the mechanisms for these in vivo and in vitro effects suggests that there may be some common basis in an "excluded volume" property of the hyaluronate, but this does not appear sufficient to explain the complexity and selectivity of the observed phenomena.
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PMID:The selective suppression of immunogenicity by hyaluronic acid. 242 4

Cytotactin is an extracellular matrix protein that is involved in neuron-glia adhesion and is found in both neural and nonneural sites. It is synthesized by glia but not by neurons. In this study, we have examined the binding of cytotactin to a variety of extracellular matrix components using uniform microscopic beads (Covaspheres) that could be labeled and then linked to purified molecules. Cytotactin-coated beads bound well to neurons, and this binding was strongly inhibited by anti-cytotactin antibodies but not by anti-neural cell adhesion molecule (anti-N-CAM) antibodies. In contrast, the binding of N-CAM-coated beads to neurons was inhibited by anti-N-CAM antibodies and not by anti-cytotactin antibodies. To identify a neuronal ligand for cytotactin, we tested several molecules for their ability to block the binding of cytotactin-coated beads to cells. A proteoglycan-containing fraction that copurified with cytotactin from brain extracts strongly inhibited binding, whereas neither a heparan sulfate proteoglycan from Engelbreth-Holm-Swarm tumor cells nor soluble cytotactin itself had a significant inhibitory effect. The neural proteoglycan also inhibited the binding of cytotactin-coated beads to fibroblasts. Digestion with chondroitinase, heparitinase, and hyaluronidase as well as immunological analyses suggested that the predominant species in the active fraction was a chondroitin sulfate proteoglycan with a Mr280,000 core protein bearing HNK-1 antigenic determinants and also indicated that hyaluronic acid was present in this fraction. In experiments on in vitro synthesis, it was found that the proteoglycan was synthesized in culture by embryonic chicken brain tissue but not by embryonic chicken glial cells. A series of binding experiments was performed on appropriately derivatized beads to confirm that the proteoglycan is a ligand for cytotactin and to check for the possibility that other extracellular matrix proteins might interact with one or the other member of this binding couple. Proteoglycan-coated beads and cytotactin-coated beads coaggregated readily. The aggregation was inhibitable by anti-cytotactin antibodies, soluble cytotactin, or soluble proteoglycan. Addition of laminin inhibited the binding of cytotactin-coated beads to proteoglycan-coated beads or to cells; this is consistent with data indicating that laminin interacts with a component of the proteoglycan-containing fraction. In contrast, fibronectin bound to cytotactin, but it did not bind to proteoglycan or interfere with the binding of cytotactin to proteoglycan. The results of this study are in accord with the idea that the functions of extracellular matrix components during neural and nonneural development may be modulated both by competition for shared cell surface receptors and by a network of molecular interactions among the matrix components themselves.
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PMID:A proteoglycan with HNK-1 antigenic determinants is a neuron-associated ligand for cytotactin. 243 34

Fibrin deposition is a consistent early event in solid tumors and healing wounds and precedes new blood vessel ingrowth in both. We now demonstrate that fibrin gels of themselves induce an angiogenic response in the absence of tumor cells or platelets. Angiogenesis was enhanced when certain chemoattractants or mitogens were included in the fibrin gel. Newly devised, inert plastic chambers with one porous surface were filled with varying contents and were implanted in the subcutaneous space of guinea pigs. Chambers filled with cross-linked homologous fibrin or plasma induced an angiogenic response within 4 days. Vessels entered chambers through the surface pores and flared out radially; angiogenesis was quantitated by point counting. Vessels were functional and matured along a gradient that proceeded from distal (least mature) to proximal. The intensity of the angiogenic response was enhanced when zymosan activated serum, an N-formylmethionine tripeptide, or platelet-derived growth factor was included in the fibrin matrix. Prior aldehyde fixation or boiling of fibrin-filled chambers inhibited angiogenesis, as did high concentrations of hyaluronic acid. Chambers filled with type I collagen or agarose did not induce new blood vessel formation, but addition of collagen did not reduce fibrin's capacity to initiate angiogenesis. The novel assay introduced here offers several advantages that should facilitate the study of angiogenesis. These include reproducibility, low background, objective and quantitative scoring, and the capacity to evaluate native molecules in animals of several species. Taken together, our findings strongly implicate fibrin or related proteins in the pathogenesis of angiogenesis and offer a new approach for elucidating the underlying molecular mechanisms.
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PMID:Fibrin containing gels induce angiogenesis. Implications for tumor stroma generation and wound healing. 244 83

A rare case of adenomatoid tumor arising in the ovary is presented. At autopsy on a 61-year-old woman, a soft, solid and cystic tumor, measuring 0.8 X 0.7 cm, was detected in the hilus of the left ovary. Light microscopic study showed characteristic features of adenomatoid tumor. Alcian blue stain, with and without hyaluronidase pretreatment, revealed the presence of hyaluronic acid on the luminal surface and in the vacuoles of the tumor cells. Immunohistochemical stains of tumor cells were positive for low-molecular-weight cytokeratin (PKKL), vimentin, and carbohydrate antigen (CA) 125, whereas they were focally positive for high-molecular-weight cytokeratin (34 beta E12). They were negative for factor VIII-related antigen (FVIII-RAG), Ulex europaeus I lectin (UEA I), carcinoembryonic antigen (CEA) and epithelial membrane antigen (EMA). Ultrastructural studies disclosed surface microvilli and bundles of tonofilaments. These observations strongly support the idea of this tumor being of mesothelial origin.
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PMID:Adenomatoid tumor of the ovary: an immunohistochemical and ultrastructural study. 245 35

Two monoclonal IgG1 antibodies (MAbs) were raised against human brain hyaluronectin (HN) and used to characterize tumor HN. They were screened using an enzyme immunological technique (ELISA) combined with the HN property of specific binding to hyaluronic acid. They were shown to detect two different epitopes (HN1 and HN2) in human normal brain as well as in most tumors. Both HN1 and HN2 epitopes were found associated with mesenchymal benign or neoplastic proliferations (e.g. connective areas of fibroadenomas, extracellular matrix of fibrosarcomas) and with reactive connective tissue (e.g. stroma reaction of carcinomas, ground substance of gliomas). The results corresponded with those previously obtained with polyclonal rabbit antibodies and confirmed that HN is a constant marker of desmoplasia. Thus anti-HN MAbs recognize an antigen that is associated with tumor development and will be suitable for targeting.
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PMID:Hyaluronectin: detection with monoclonal antibodies in human tumors. 245 45

The capacity of various blood-borne cells, whether normal or malignant, to extravasate was found to correlate with heparanase-mediated degradation of HS in subendothelial ECM. This degradation was stimulated by proteases or plasminogen and inhibited by native heparin and by various modified nonanticoagulant species of heparin. These heparins also induced a marked reduction in tumor cell metastasis and autoimmune diseases in experimental animals. Heparanase-mediated degradation of HS in ECM also released EC growth factors that are stored in ECM, most likely by high affinity binding to HS. Such growth factors were extracted from subendothelial ECM synthesized in vitro and from basement membranes of the cornea in vivo, and are structurally and functionally related to bFGF;bFGF binds to ECM and is readily released by incubation with either HS, heparin or low MW heparin fragments as well as by various normal and malignant cells and by heparanase-mediated degradation of ECM HS. In contrast, there was little or no release of growth-promoting activity upon incubation of ECM with hyaluronic acid, chondroitin sulfate or chondroitinase ABC. A model is proposed suggesting that regulation of capillary growth and neovascular response may result from displacement of an angiogenic protein (bFGF) from its storage sites within basement membranes.
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PMID:Involvement of heparanase in tumor metastasis and angiogenesis. 246 49

One hundred and twenty-one patients with gastric cancer of Borrman IV (type 4) were classified into two types according to the macroscopic appearance of their tumors, namely, those tumors with giant folds (type G, n = 84) and those without giant folds (type P, n = 37). A large percentage of the cases in both type groups had advanced stage carcinoma. Type G was found to be predominant in young women and the incidence of high-grade lymph node metastasis was higher in type G than in type P. Histochemically, it was shown that the tumor interstitium of type G contained obviously many more acid mucopolysaccharides (AMPS) than the localized Borrman II (type 2) gastric cancer, which was used as a control. The results of enzymatic digestion tests suggested that the amounts of hyaluronic acid, chondroitin sulfate, and sialic acid were greater in type G than in type P or the localized type, the differences involved being marked between type G and the localized type.
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PMID:Clinico-histochemical studies on type 4 carcinoma of the stomach--with special reference to mucopolysaccharides and sialic acid in tumor tissue. 247 Sep 45

Plexiform neurilemmoma (PN) is a rare benign peripheral nerve sheath tumor. The tumor is an uncommon nodular variant of schwannoma. Eleven cases of cutaneous plexiform neurilemmoma (CPN) were studied by clinicopathologic correlation, immunohistochemistry, and electron microscopy. The patients' ages ranged from 6 to 80 yr; the median age was 37 yr. The tumors were presented as single, soft to rubbery, movable, nontender, and sometimes painful nodules ranging from 0.5 cm to 2.5 cm. in diameter. The lesions were most commonly located on the extremities. The overlying skin surface was intact. These tumors were not associated with von Recklinghausen's neurofibromatosis or neurilemmomatosis. On gross examination the cut surface of the tumors showed grayish-white to yellow or tan coloration and had a well-defined border, but there was no evidence of a plexiform growth pattern. The microscopic features were characterized by single or multiple well-circumscribed nodules of spindle-shaped tumor cells. The nuclei were irregular and elongated, and the cytoplasm was eosinophilic and fibrillary without distinct cytoplasmic borders. Nuclear palisading was prominent, and Verocay bodies were present. Mitotic figures were rare (fewer than 2 per 20 high-power fields). Bodian stain showed presence of nerve fibers at the periphery of the tumor. The adjacent tissue showed wavy, spindle-shaped cells and collagen fibers in a myxoid stroma rich in hyaluronic acid, a pattern reminiscent of neurofibroma. The tumor cells showed positive reactivity with anti-S-100 protein in both the nuclei and cytoplasm. Glial fibrillary acid protein was focally positive, and neuron-specific enolase was negative. Electron microscopy displayed features of Schwann cells.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Solitary cutaneous plexiform neurilemmoma (schwannoma): a clinicopathologic, immunohistochemical, and ultrastructural study of 11 cases. 249 41


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