Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:1.11.1.7 (peroxidase)
65,474 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A variety of antigens may be detected in the serum of patients with hepatocellular carcinoma (HCC). The incidence and distribution of five antigens in 37 HCC and their relation to each other in a given tumor was examined by the peroxidase-antiperoxidase technique using formalin-fixed paraffin-embedded tissues. alpha 1-Antitrypsin was frequently expressed in HCC (73 per cent of cases), whereas alpha-fetoprotein and carcinoembryonic antigen were less common. HBsAg, but not HBcAg, was observed in tumor cells in seven of nine HCC from HBsAg-positive patients. In 20 HCC (54 per cent), two or more antigens, most frequently alpha 1-antitrypsin and alpha-fetoprotein, were detected. Double staining for simultaneous localization of two antigens in the same tissue section revealed that different antigens were usually present in different tumor cells, although some cells displayed two antigens simultaneously. These findings suggest that hepatocellular carcinoma cells are functionally heterogeneous, even if they appear histologically monomorphic.
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PMID:Distribution of five antigens in hepatocellular carcinoma. 8 43

Biochemical characterization of serologically detected human melanoma antigens was undertaken for the development of immunodiagnostic assays in melanoma. An antiserum from a human melanoma patient, which detected melanoma antigens expressed on a large proportion of different melanoma cells, was used in leucocyte-dependent cytotoxic antibody (LDA) 51Cr-release assays to monitor the purification of melanoma antigens in urea/acetate extracts of lactoperoxidase 125I-labelled melanoma cell membranes. The separation procedures included affinity chromatography on Concanavalin A, gel filtration on porous polyacrylamide beads and preparative isoelectric focusing. The fractions were also monitored by polyacrylamide electrophoresis in sodium dodecyl sulphate and by measurement of beta 2 microglobulin and carcinoembryonic antigen content. The antigens detected by this antiserum appeared to be acidic (pI 3.5) low-mol.-wt glycoproteins of approximately 15,000 daltons which were resistant to heating at 56 degrees C and digestion with neuraminidase, but susceptible to repeated freeze-thawing and trypsin digestion. They did not appear to be related to HLA antigens, beta 2 microglobulin or known foetal antigens. The nature of the antigens detected in these studies is as yet unknown, but they appear similar to those described in the sera and urine of melanoma patients in previous reports. Thes combined results and the frequent expression of these antigens on melanoma cells from different patients suggest that assays to detect this antigen may provide a valuable immunodiagnostic aid in the management of melanoma.
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PMID:Detection of a low-molecular-weight antigen on melanoma cells by a human antiserum in leukocyte-dependent antibody assays. 9 79

Two different fixatives were applied to human gastric mucosa for the study of antigenic marker substances. The first consists of 96% ethanol and 1% acetic acid (EA method), the second of 4% formaldehyde, 0.5% picric acid and 0.25% glutaraldehyde (FPG method). Samples of resected gastric specimens were fixed, dehydrated and cleared in benzene and embedded in paraplast. The morphology of gastric tissue was well preserved by both methods and permitted the simultaneous application of classical staining procedures and the immunoenzyme peroxidase technique for the demonstration of antigenic substances. The following marker substances could be demonstrated: Pepsinogen I and II group, surface epithelial antigen, parietal cell antigen, chief cell antigen, antral mucous cell antigen, carcinoembryonic antigen, goblet cell antigen and common site antigen of leucocytes. Various factors responsible for nonspecific reactions, such as endogeneous peroxidase activity and protein interactions were studied. The latter were circumvented by the use of highly purified antibodies or immunoglobulin fractions. The EA method proved to be the method of choice for future routine application of combined classical histology and immunoenzyme histology in gastric and intestinal diseases.
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PMID:Immunohistochemical studies on human gastric mucosa. Procedures for routine demonstration of gastric proteins by immunoenzyme techniques. 15 Jan 10

A highly sensitive method for the immuno-histochemical localisation of carcinoembryonic antigen (CEA) is described. This method is based on the binding of a peroxidase-antiperoxidase complex (PAP) to anti-CEA antibodies by means of an anti-gamma-globulin which reacts with both the anti-CEA and the antiperoxidase antibodies. Using the technique described here, CEA was localised in conventionally processed normal and cancerous colonic tissue. In normal as well as in neoplastic tissues, a CEA-specific staining of cell membranes and cytoplasm was demonstrated. In frozen sections of normal colonic tissue CEA was found even at high dilutions of the first antibody; this indicates the high sensitivity of the method. The applicability of the method to conventionally processed and thereby well preserved tissue specimens opens the possibility to identify CEA by light microscopy even at very low concentrations.
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PMID:A highly sensitive method for the demonstration of carcinoembryonic antigen in normal and neoplastic colonic tissue. 36 35

Alterations in cell surface glycoproteins have been implicated in malignancy. We examined surface membrane proteins of a cultured cell line, SKCO-1, which had been derived from a human colonic adenocarcinoma. Cell surface labeling of SKCO-1 cells with galactose oxidase, followed by reduction with sodium borotritide, revealed five major labeled glycoproteins upon sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis. At least three additional labeled glycoproteins could be detected if galactose oxidase treatment was preceded by neuraminidase treatment. Some, but not all, of the glycoproteins could be iodinated by lactoperoxidase. The predominantly labeled glycoprotein (GPI) had a molecular weight of 200,000 and co-migrated in SDS gel with carcinoembryonic antigen (CEA). GPI was not removed from the cell surface by EDTA, hypertonic saline, or sonication but was released from the membrane by detergents. This glycoprotein was subsequently purified using lectin-agarose columns and gel filtration. GPI was judged homogenous by protein- and carbohydrate-stained SDS-polyacrylamide gels and had an amino acid composition similar to that of CEA. The carbohydrate composition of GPI was qualitatively similar to CEA but quantitatively distinct. GPI had a greater proportion of sialic acid and galactosamine and less fucose and glucosamine than CEA. Immunological studies, however, demonstrated identity between GPI and CEA. A study of the turnover rate of GPI showed it to have a half-life of 5 days.
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PMID:Glycoproteins from human colonic adenocarcinoma. Isolation and characterization of cell surface carcinoembryonic antigen from a cultured tumor cell line. 41 28

A triple-bridge, indirect peroxidase-antiperoxidase method for demonstrating carcinoembryonic antigen (CEA) in frozen, ethanol-fixed or formalin-fixed, paraffin-embedded specimens was evaluated. Examination of 359 tissue specimens--234 malignant tumors, 37 benign neoplasms, 41 nonneoplastic diseased tissues, and 47 normal specimens--showed that CEA could usually be demonstrated in a group of cancers. We could detect CEA in carcinomas of the stomach, colon, rectum, pancreas, lung, and cervix. However, malignant tumors of the breast, prostate, kidney, larynx, brain, lymphoreticular system, soft tissues, and skin proved negative for CEA by the immunoperoxidase test. CEA could be detected in ethanol- or formalin-fixed sections. The only nonmalignant specimens showing CEA staining were a few benign tumors, the mucosae of some cases of colitis, and the resection margins of 2 cases of colon cancer; however, these were commonly very weak reactions. Measurement of tumor CEA content by radioimmunoassay revealed two causes for this relative specificity of the immunoperoxidase test for CEA:1) a quantitative difference existed in tissue CEA among the various specimens, and 2) the threshold for CEA staining in malignant specimens was usually above that in nonmalignant specimens. An analysis of the formalin-paraffin-treated sections showed that immunoperoxidase-tested CEA positivity reflected CEA levels in tissue of at least 3.0-5.0 mug/g; this permitted retrospective estimates of minimal tissue CEA concentrations in older histopathologic specimens by the immunoperoxidase reaction method. Formalin-paraffin-treated sections as old as 10 years still had demonstrable CEA. Although tumor CEA concentration correlated well with immunoperoxidase staining for CEA, plasma CEA titer did not necessarily reflect tumor CEA content. CEA positivity in primary and secondary tumors was strongly correlated; it was less strongly correlated with level of tumor differentiation.
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PMID:Carcinoembryonic antigen in histopathology: immunoperoxidase staining of conventional tissue sections. 79 93

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

One of the important factors affecting the action of monoclonal antibodies (Mabs) or immunoconjugates on tumour sites depends on whether the Mab is internalized by the cancer cells in question. The underexplored subject of internalization is discussed in this paper, and a number of in vitro techniques for investigating internalization are evaluated, using a model which consists of a well characterized anti-carcinoembryonic antigen (anti-CEA) Mab and a number of CEA expressing human cancer cell lines. Employing two alternative radiolabeling assays, evidence for internalization of the anti-CEA Mab by a CEA-positive colorectal cancer cell line (LS174T) was obtained throughout the time intervals examined (5 min to 150 min). Electronmicroscopy employing horseradish-peroxidase labeled anti-CEA Mab and control antibody permitted direct visualization of anti-CEA Mab-related staining in intracellular compartments of a high CEA-expressor human colorectal cell line (SKCO1). Finally Western blots of samples derived from cytosolic and membrane components of solubilized cells from lung and colonic cancer cell lines provided evidence for internalized anti-CEA Mab throughout seven half hour intervals, starting at 5 minutes. Internalized anti-CEA was detected in all CEA expressing cell lines (LS174T, SKCO1, BENN) but not in the case of a very low CEA expressor line (COLO 320).
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PMID:Demonstration of monoclonal anti-carcinoembryonic antigen (CEA) antibody internalization by electron microscopy, western blotting and radioimmunoassay. 129 59

A generally applicable method for the determination of the epitope specificities of a large number of monoclonal antibodies (MAbs) is presented. The method is based on the solid-phase mutual inhibition assay using 96-well plates coated with the respective MAbs, competitor MAbs, biotinylated antigen and avidin-peroxidase conjugate. Using carcinoembryonic antigen (CEA) as a model antigen the method was applied to the determination of epitope specificities of anti-CEA MAbs. A constant amount of biotinylated CEA was incubated with a given MAb immobilized on wells of 96-well plates in the presence of increasing amounts of soluble competitor MAbs. The biotinylated CEA bound to the immobilized antibody were then reacted with avidin-peroxidase conjugate and the activity of the bound peroxidase was determined by the use of o-phenylenediamine and hydrogen peroxidase. The method used here alleviates the laborious procedures of labeling all antibodies to be tested and the confusion caused by differential labeling among different MAbs, and is convenient for mapping analysis of many MAbs if the corresponding purified antigen is available.
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PMID:Determination of epitope specificities of a large number of monoclonal antibodies by solid-phase mutual inhibition assays using biotinylated antigen. 138 23


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