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)

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

The metabolic pathways associated with carcinogenic aromatic amines in humans provide an excellent example of polymorphisms that appear to be relevant to human carcinogenesis. In this regard, the N-acetylation of arylamines and the O-acetylation of their N-hydroxy metabolites are catalyzed preferentially by a genetically polymorphic acetyltransferase, high activity of which has been correlated with decreased risk for urinary bladder cancer and increased susceptibility to colorectal cancer. Cytochrome P450IA2, the principal liver enzyme involved in aromatic amine N-oxidation, exhibits a wide interindividual variation that appears trimodal in several populations and is clearly inducible by cigarette smoking and probably other host factors as well. UDP-Glucuronosyltransferases, which catalyze the N-glucuronidation of N-hydroxyarylamines and are likely to be responsible for their transport to the colon, show widely varied but unimodal distributions in humans. In contrast, human liver sulfotransferase activity for N-hydroxyarylamines, which would be expected to decrease their transport through the circulation, is catalyzed by a polymorphic enzyme(s) that is expressed at higher levels in blacks, as compared to whites, and could contribute to their relatively lower incidence of urinary bladder cancer. Peroxidative activation of aromatic amines can also occur, especially from prostaglandin H synthase in the urinary bladder and myeloperoxidase in the lungs of cigarette smokers, and both show considerable individual variability, apparently due to the extent of tissue inflammation.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Polymorphisms for aromatic amine metabolism in humans: relevance for human carcinogenesis. 148 65

We studied rectal cell proliferation by means of bromodeoxyuridine labelling and ornithine decarboxylase activity assay in 16 patients with colorectal adenoma. In each patient, three rectal biopsy specimens taken from normal-appearing mucosa were incubated with bromodeoxyuridine (BrdU), fixed in ethanol and stained with avidin-biotin peroxidase complex using a monoclonal antibody against BrdU. In addition, two biopsies were homogenized and incubated with [1-14C]-ornithine for ornithine decarboxylase (ODC) assay. A direct, significant correlation was found between BrdU-labelling index and ODC levels in the mucosa (r = 0.6511, P less than 0.01). We conclude that BrdU labelling and ODC activity assay give comparable results in the analysis of cell proliferation rate of rectal mucosa. These methods are useful to investigate rectal cell proliferation pattern of patients with increased risk of colorectal cancer.
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PMID:Correlation between bromodeoxyuridine labelling and ornithine decarboxylase levels in normal rectal mucosa of patients with colorectal adenoma. 191 17

The question of what the most accurate and efficient fecal occult blood testing method is for the early detection of pathological gastrointestinal tract bleeding continues to be intensely debated. In this prospective study, the following five uniquely different slide tests were investigated in 120 patients who underwent gastrointestinal tract investigation: (1) a combination monoclonal antibody guaiac test (Monohaem); (2) an immunologic assay, enzyme-linked immunosorbent assay, with (3) a highly sensitive guaiac test (Fecatwin S/Feca enzyme immunoassay), (4) a popular guaiac test (Coloscreen III) (comparable with Hemoccult II), and (5) Coloscreen III/VPI (ie, with vegetable peroxidase) inhibitor. Computerized data show efficiency values for detection of fecal occult blood by Coloscreen III-Fecatwin S-Monohaem combined, 93%; Coloscreen III-Monohaem combined, 91%; Monohaem, 87%; Coloscreen III/VPI, 82%; Coloscreen III, 79 percent; enzyme-linked immunosorbent assay, 77%; and Fecatwin S, 68%. Results of sensitivity, specificity, false-positive and false-negative test results, tests' predictive value, simplicity, and costs of tests in this clinically based study suggests that the concomitant use of the monoclonal, monospecific test for human hemoglobin and an appropriately sensitive guaiac test is a potentially valuable approach to mass screening and early detection of occult bleeding gastrointestinal tract pathology, including colorectal cancer.
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PMID:A comparative study of fecal occult blood tests for early detection of gastrointestinal pathology. 233 Nov 99

Four hybridomas secreting monoclonal antibodies (MAbs) of the IgG1 subclass against human carcinoembryonic antigen (CEA) were obtained from fusion of P3-NS1/1-Ag4 myeloma cells with splenic cells from mice immunized with purified CEA. None of the MAbs showed cross-reactivity to perchloric acid extractable antigens from the normal human colon by an inhibition radioimmunoassay. However, MAb C27 showed the highest affinity to CEA. The intensity of immunofluorescence staining of human colorectal cancer cells with MAb C27 correlates well to the cellular CEA content of cancer cells. LS174T showed the highest intensity of fluorescence (95%) while COLO320DM and COLO320HRS were the lowest (0.5%). None of the normal human organs - colon, lungs, liver, spleen or kidneys-showed positive staining by immunoperoxidase anti-peroxidase (PA) techniques, while tissues from colorectal carcinoma (CRC), gastric carcinoma, hepatoma and lung cancer gave a positive rate of 100% (30/30), 96.6% (28/29), 32.1% (9/28) and 82.1% (69/84) respectively. Results suggest that MAb C27 can be used in immunodetection and radiolocalization of colorectal carcinoma.
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PMID:Immunological characteristics of monoclonal antibodies against human carcinoembryonic antigen (CEA). 241 36

The authors investigated the level of lipid peroxidation and possible related phenomena in the activation of phospholipase A2 and the infiltration of granulocyte neutrophils in human colorectal cancer tissue samples. Malondialdehyde (an index of lipid peroxidation), phospholipase A2 activity, and myeloperoxidase activity (a marker of granulocyte neutrophils) were found to be increased significantly in cancerous compared with macroscopically normal tissues. They concluded that increased lipid peroxidation, phospholipase A2, and myeloperoxidase activity are associated with human colorectal cancer.
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PMID:Increased lipid peroxidation in malignant tissues of patients with colorectal cancer. 254 50

Adenosine deaminase complexing protein (ADCP), a dimeric glycoprotein, has been reported to be decreased or deficient in transformed or cancer-derived cell lines, indicating its potential significance as an indicator of malignant transformation. A similar deficiency was reported in total homogenates of tumours of colon, kidney, lung and liver. In previous biochemical studies we failed to confirm the consistent reduction in ADCP concentration in cancer tissues. A possible explanation for our findings was thought to be intercellular heterogeneity in ADCP expression in individual tumour cells. To study ADCP expression in individual cells, we developed an immunohistochemical method which was applied to tissue sections. Paraformaldehyde--lysine--periodate (PLP) solution was found to be a suitable fixative. Fixed tissue samples were paraffin-embedded, sectioned and stained for ADCP, using an indirect peroxidase-labelled antibody procedure. The protein was localized in normal colonic mucosa, mainly in the brush border region of the luminal epithelium and in cytoplasmic granules. Intense ADCP immunoreactivity was found also in the basal part of some cells. In cancer cells, three staining patterns were observed: membranous, diffuse cytoplasmic and granular cytoplasmic. The adenocarcinomas exhibited significant intratumour and intertumour heterogeneity in their staining types. Further studies on ADCP expression in colorectal cancer in relation to clinical and histopathological characteristics are warranted in order to fully evaluate the potential significance of ADCP as a cancer associated antigen.
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PMID:Immunohistochemical localization of adenosine deaminase complexing protein in intestinal mucosa and in colorectal adenocarcinoma as a marker for tumour cell heterogeneity. 285 62

Occult blood testing for detection of asymptomatic colorectal cancer is an old concept. The authors review the literature about the screening value of current tests. Among the chemical tests, Hemoccult is the most popular and the best studied. Sensitivity and specificity are moderate. False negative reactions are due either to the test itself (high level of sensitivity, loss of reactivity) or to the tumour (intermittent or insufficient bleeding, localization etc...). False positive reactions are due to the interference of a high peroxidase diet. The Hemoccult test is nevertheless interesting because it is simple, cheap and well accepted. Detected cancers tend to be at a relatively early stage: 60 to 80% of Dukes A or B. New methods--Hemoquant and immunochemical methods--are being developed. Their high degree of sensitivity and specificity for human hemoglobin makes them too complex and too costly. Whatever the efficacity of a test to detect occult blood may be, we must know whether the screening of an asymptomatic population could decrease the mortality rate of colorectal cancer, before using it on a large scale. Only long-term controlled trials can give us an answer in the future.
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PMID:[[Evaluation of various methods of studying fecal occult blood]. 297 53

In this clinical trial, 786 patients screened for colorectal cancer with fecal occult blood testing were assigned to either a "diet" or "no diet" group to examine the effect of advice to restrict intake of red meat and peroxidase-containing vegetables on patient compliance and positivity rates. Restrictive diets did not significantly decrease compliance. Interviews of patients in the "diet" group demonstrated that the majority followed instructions. Positivity rates were similar in the two groups, and clinically significant lesions were found with comparable frequency.
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PMID:Compliance with fecal occult blood testing: the role of restrictive diets. 338 64

Because of the recent increase in the incidence of colorectal cancer in Japan, attempts were made to find an effective method for screening asymptomatic patients with this cancer. In current mass screening, guaiac-impregnated slides such as the Shionogi and Hemoccult types are widely used. A screening system consisting of examination with Shionogi B slides for 3 consecutive days under mild restricted diet and a medical questionnaire, followed by re-examination under a restricted diet for persons showing a partially positive result is accepted as the most reliable screening method. As these slide tests are based on peroxidase-like activity in hemoglobin, dietary fiber, meat, peroxidase-containing foods and drugs influence the sensitivity and specificity of the test. Recently, immunological fecal occult blood tests with high sensitivity and specificity such as RPHA or Feca-EIA have been developed. We have evaluated the RPHA method and compared it with the Shionogi B slide. The positive rate of the RPHA method was rather lower than that of the Shionogi test and the detection rate of Colorectal cancer was equivalent to that of Shionogi. We are now applying the RPHA method to mass screening, and the Feca-EIA Test is also under consideration for practical use.
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PMID:[Occult blood screening for colorectal cancer]. 372 85


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