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

The binding of concanavalin A (Con A) at the free apical membranes of surface tumor cells in human breast cancer explants grown in organ culture was studied cytochemically with horseradish peroxidase (HRP) as a marker. On the cell membranes in aldehyde-fixed explants or explants exposed to Con A at 4 degrees C, a continuous label covered the entire free surface of the cell, which indicated the dispersed distribution of Con A binding sites. The binding of Con A at 20 degrees C resulted in discontinuous label of the cell surface, with gaps of unlabeleled membrane and partial endocytosis of the label. Incubation at 37 degrees C, following the binding of Con A and HRP at both temperatures, induced more extensive, incubation time-dependent discontinuities of the surface label that led to complete disappearance of the label from the surface and its eventual endocytosis. Con A was topically stablized on the surface only in those regions where two membranes or a different part of a folded membrane were in close contact. No differences were found in the binding, redistribution, and internalization of bound Con A among the various tumors studied.
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PMID:Concanavalin A receptors on the surfaces of human breast cancer cells in organ culture. 83 61

The use of Lens culinaris lectin for electron microscopic detection of D-mannose,- D-glucose and N-acetyl-D-glucosamine like sites on tumor cells, erythrocytes, erythrocyte ghosts, cultured rat liver cells and various tissues of mice is demonstrated. In addition to Lens culinaris lectin-peroxidase reaction (LeL-po reaction) the preparation of active Lens culinaris lectin-ferritin conjugate are described and the specificity of cytochemical reactions are demonstrated. Furthermore experiments by immuno freeze-etching are reported for topological analysis of the lectin receptors.
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PMID:Electron microscopic demonstration of cell surface carbohydrates by means of peroxidase and ferritin complexes of the Lens culinaris lection. 115 Apr 86

Ultracytochemical visualization of specific carbohydrate receptors by means of lectins can provide valuable topological information about the functional status of cell surfaces in normal and transformed cells. In addition to the concanavalin A (Con A) rection and precoupling of lectin--peroxidase (PO) a new method is suggested using precoupling of the marker enzyme (PO) with an appropriated glycoprotein (glycopeptide) containing a lectin-specific carbohydrate. Furthermore, quantitative estimations of Con A reaction by means of automatic umage analysis are performed on peritoneal macrophages which point out a cluster formation, but give no hints for a loss of glycocalyx during the preparation process contrary to tumor cells.
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PMID:Methodological approaches to the study of carbohydrate surface receptore on macrophages and tumor cells. 116 Nov 11

A triple-bridge, indirect, immunoperoxidase method for detecting and localizing carcinoembryonic antigen (CEA) in tissue sections is described. By this technique, a cell-surface localization of CEA in colonic carcinoma and ovarian mucinous cystadenocarcinoma cells could be visualized. In the case of the colonic cancer, both the tumor from the descending colon and a metastasis to the skin gave positive peroxidase reactions for CEA. This immunocytochemical method for demonstrating the presence of CEA functioned in both frozen, ethanol-fixed and formalin-fixed, paraffin-embedded tissues, thus making it applicable for use with tissue sections conventionally prepared for light microscopy.
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PMID:Detection of carcinoembryonic antigen in tissue sections by immunoperoxidase. 123 19

An immunoenzymologic method using peroxidase-labeled antibodies has been applied for the localization of carcinoembryonic antigen (CEA) on frozen sections, on Araldite-embedded sections, and on isolated cell preparations of normal rectocolonic mucosa and of rectal and colonic cancers (adenocarcinomas and one villous tumor). CEA appears as a component intimately associated with the external coating of the striated border of the normal columnar cell and with the external coating of the apical pole of the cancerous cell. CEA is also found as an intracellular component of the normal epithelial cell of the rectocolonic mucosa, mainly the goblet cell. In tumors, it appears as an intracellular component of the mucussecreting cell. Its presence in the cell coat and interior of the cell correlates with the degree of differentiation of the cells, whether cancerous or not. Progressive accumulation of CEA in the normal colonic epithelial cell has been observed in cells undergoing maturation. Its release by the mature goblet cell has also been observed. These results confirm that CEA is a normal glycoprotein constituent of the epithelial cell of the human adult rectocolonic mucosa, synthesized and discharged by this cell. The difference in CEA content, already reported, between the cancerous and the normal rectocolonic mucosa appears quantitative and not qualitative.
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PMID:An optical and ultrastructural study of the localization of carcinoembryonic antigen (CEA) in normal and cancerous human rectocolonic mucosa. 124 27

Tumor emboli were produced in lungs of Sprague-Dawley rats by i.v. injection of Walker 256 tumor cells into the tail vein. Tissues were examined by electron microscopy at periods from 30 sec to 72 hr after tumor injection. Two methods of conventional staining were used, in addition to immunoperoxidase techniques, with antifibrin antibodies produced in rabbits. Tumor cells accompanied by a platelet mass were seen in pulmonary arterioles at the earliest time period (30 sec). By conventional staining, small amounts of fibrin were detected within the platelet clumps by 5 min after inoculation. Periodicity indicating stable fibrin was not seen by this technique until 15 to 45 min. When peroxidase-labeled antibody was applied to tissue, sections showed fibrin-positive material at 30 sec, and periodicity of fibrin was detected by 5 min. Fibrin reached a maximum by both techniques at about 1 hr and disappeared, along with the platelets, at about 9 hr. When fibrinolysin was injected prior to the tumor cell inoculation, platelets and fibrin were either absent or present only in traces, and no stable fibrin was detected. These observations show that fibrin occurs very early in small amounts in association with tumor cell emboli, and is removed while the cells are still intravascular.
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PMID:Demonstration of fibrin in early stages of experimental metastases. 126 44

The aim of this study was to evaluate whether interferon [IFN] can affect intracerebrally grown glioma and how alteration of the blood-brain barrier [BBB] may influence this effect. An intracerebrally implanted glioma G-26 (G-26) mouse brain-tumor model was developed and used in these studies. Histological characterization of this intracerebrally grown tumor revealed its anaplastic character. The astrocytic origin of G-26 was evidenced by glial fibrillary acidic protein staining and electron microscopic visualization of glial filaments. A study of tumor progression and animal survival showed development of a well defined tumor nodule within approximately seven days after the implantation. The median animal survival time was 27 +/- 3.8 days. The integrity of the blood-brain barrier [BBB] within the tumor was evaluated by the intravenous injection of horseradish peroxidase at days 3, 7, 10 and 20 after brain tumor implant and compared to 'sham' controls. The tumor-induced BBB alteration was progressive from day 3 to day 20. Glioma-26 subcutaneously passed in C57BL/6 mice was also continuously cultured in vitro. Its proliferation was inhibited by homologous mouse interferon alpha/beta [MuIFN alpha/beta] but not by human interferon alpha lymphoblastoid or human interferon beta. The in vivo studies of G-26 glioma treatment with MuIFN alpha/beta were performed using single bolus of IFN in osmotically altered animals or slow IFN infusion through osmotic micro-pumps. The slow infusion of IFN had no effect on animal survival. However, a statistically significant increase in animal survival was observed after single bolus IFN treatment following osmotic BBB alteration.
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PMID:Evaluation of blood-brain barrier permeability and the effect of interferon in mouse glioma model. 128 Dec 26

A 60-year-old male with elevated serum AFP levels is reported. Other tumor markers apart from AFP were normal. Serum AFP did not bind to Con A or Lentil-lectin by affinity chromatography. Abdominal ultrasonography, computed tomography and endoscopic retrograded cholangiopancreatography demonstrated a tumor extending from the body to the tail of the pancreas. The tumor was strongly suggested to be an acinar cell carcinoma of the pancreas, based on the histological findings of the resected specimen. The peroxidase-antiperoxidase method showed cancer cells to be positive for AFP. In Japan, only 27 cases of pancreatic cancer with elevated serum AFP level have been reported. This is the first Japanese case of pancreatic cancer in which the binding of serum AFP to lectins was investigated.
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PMID:Acinar cell carcinoma of the pancreas with elevated serum alpha-fetoprotein levels: a case report and a review of 28 cases reported in Japan. 128 98

The role of selenium concerning its biological effects particularly in relation to cardiovascular and tumor diseases has been in the focus of intensive studies. Selenium is a constituent part of the enzyme glutathion peroxidase (E.C.1.11.1.9) which catalyzes the conversion of hydrogen peroxide and organic hydroperoxides into water and corresponding alcohols. A review of epidemiological studies is presented focusing predominantly on countries where a low concentration of selenium in blood serum was found. The role of selenium in the etiology of cardiovascular diseases may probably be accounted for by its protective effect as it prevents platelet aggregation and protects the arterial endothelium from being damaged by lipid peroxides. The results of experimental studies, carried out in research institutes in many parts of the world, suggest that coordinated supplementation of food with selenium may reduce the risk of cancer and moreover, the effect of selenium can be modified by other dietary factors, such as vitamin A and E. (Fig. 2, Ref. 29.)
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PMID:[Biological effects of selenium]. 129 55

Several studies have indicated a correlation between the presence of inflammation and the development of cancer. The aim of our study was to determine if pulmonary neutrophils could transform the proximate respiratory carcinogen (+-)-trans-7,8-dihydroxy-7,8-dihydrobenzo[a]pyrene (B[a]P-7,8-diol), to an ultimate carcinogenic metabolite via myeloperoxidase (MPO). To test this hypothesis, virus-free male DBA/2 mice were exposed by inhalation to the Gram-negative bacteria Proteus mirabilis for 1 h. For various time points post-exposure, bronchoalveolar lavage (BAL) was performed to determine total and differential cell counts, cellular MPO activity and production of superoxide. Twelve hours after the exposure, cellular activity of MPO as well as percentage and total number of polymorphonuclear leukocytes peaked and declined thereafter. At this same time point, cells from BAL exhibited increased release of superoxide, as measured by reduction of cytochrome c, after addition of soluble or particulate stimuli, 12-O-tetradecanoylphorbol-13-acetate (TPA) or opsonized zymosan respectively. These cells also elicited biotransformation of B[a]P-7,8-diol as evidenced by enhanced B[a]P-7,8-diol-derived chemiluminescence, tetraol formation and covalently bound adduct formation to exogenous DNA upon addition of TPA or opsonized zymosan. Moreover, the cell-free BAL fluid of infected mice contained substantial MPO activity in comparison to that of uninfected animals. Also, MPO enhanced the binding of B[a]P-7,8-diol to lung DNA in vitro. Unlike previous work emphasizing the potential roles of oxygen free radicals in tumor promotion, our results indicate a role of neutrophilic MPO in the initiation of carcinogenesis.
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PMID:Myeloperoxidase-enhanced formation of (+-)-trans-7,8-dihydroxy-7,8-dihydrobenzo[a]pyrene-DNA adducts in lung tissue in vitro: a role of pulmonary inflammation in the bioactivation of a procarcinogen. 132 50


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