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)

The localization of lectin-binding sites in the rat gastric mucosa was investigated using horseradish peroxidase-labeled lectin conjugates (Con A, DBA, PNA, RCA-1, SBA, UEA-1, WGA). The glandular epithelium of the cardiac gland was clearly stained with DBA, PNA and SBA. Surface epithelium of the fundic glands was intensely labeled with SBA and UEA-1, but weakly with RCA-1, and WGA. Staining for foveolar cells was intense with SBA and moderate with PNA, while Con A and RCA-1 showed negligible reactivity. Mucous neck cells were intensely stained with SBA, moderately with PNA, weakly with Con A, RCA-1 and WGA, and only, faintly with DBA. Chief cells reacted positively only with WGA. Surface epithelium of the pyloric gland was moderately labeled with DBA, SBA and WGA, and faintly with the other lectins. Glandular epithelial cells, which revealed a similar pattern to that of the surface epithelium, were stained more intensely. The present study provides additional information for elucidating the cellular and regional differences in lectin binding to the rat gastric mucosa.
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PMID:Lectin-peroxidase reactivity in rat gastric mucosa. 620 16

Intracisternal Type A particles (IAPs) are retroviruslike structures identified by a core protein antigen (p73) and found in mouse embryos, in many mouse tumor cells, and in pancreatic B cells of some strains of genetically diabetic mice. Using both peroxidase-antiperoxidase and protein A-gold immunocytochemical techniques to localize p73, the authors have observed differences in intracellular antigen distribution between MOPC-104E, a mouse tumor cell line rich in IAP, and B cells from genetically diabetic (db/db) mice of the CBA/LtJ and C57BL/KsJ strain. In MOPC-104E cells studied by electron microscopy, localization of protein A-gold complex label was almost exclusively limited to IAP and their sites of assembly on the rough endoplasmic reticulum. In contrast, p73 appeared widely distributed throughout the cytoplasm of B cells from hyperglycemic db/db mice but not normal littermate controls. In addition to distribution over budding IAP, label was also found dispersed through other cytoplasmic organelles involved in secretion, including Golgi complexes and secretory granules. Patch labeling of B cell surfaces was sometimes observed. An ultrastructural survey of islets isolated from normal mice of 7 inbred genetic backgrounds on which the "diabetes" (db) gene has been studied showed that constitutive ability to produce IAP was associated with strain susceptibility to severe diabetes (eg, C57BL/KsJ, DBA/2J, CBA/LtJ, and C3HeB/FeJ). Strains whose B cells failed to show constitutive expression in situ or glucose-inducible expression in cell culture were resistant to the diabetogenic action of db genes. The possibility is discussed that p73 may represent a "neoantigen" which sensitizes the diabetic mouse to reject, by autoimmune mechanisms, the B cells expressing it.
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PMID:Intracisternal Type A particles in murine pancreatic B cells. Immunocytochemical demonstration of increased antigen (p73) in genetically diabetic mice. 636 24

Complex carbohydrates in premalignant lesions of mouse submandibular gland tumors were examined by the lectin-peroxidase conjugate method. Peroxidase-conjugated lectins of PNA, RCA-1, DBA, SBA, UEA-1 and WGA were used to detect specific sugar residues of complex carbohydrates in premalignant lesions during experimental carcinogenesis. Marked reduction of PNA and SBA bindings occurred in duct-like structures and cystic lesions which were transformed from granular convoluted tubule cells. Premalignant lesions bound slightly to PNA, RCA-1, DBA, SBA and WGA and manifested increased UEA-1 binding. Squamous metaplastic epithelia of premalignant lesions manifested increased binding to PNA, RCA-1 and SBA as compared to those of duct-like structure and cystic epithelia.
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PMID:Lectin-binding in premalignant lesions during submandibular gland carcinogenesis. 643 17

The human breast cancer cell lines MCF-7 (ER positive), ZR 75-1 (ER positive) and MDA-MB 231 (ER negative) form solid tumors within one week following inoculation into athymic nude mice. Tumor formation by MCF-7 and ZR 75-1 cells was dependent upon estrogen, whereas MDA-MB 231 cells formed tumors in ovariectomized mice with or without supplemental estrogen. Ultrastructural comparison of tumors formed by the three human breast carcinoma lines in athymic nude mice indicated that lactoperoxidase activity, milk protein and fat globule formation were virtually absent from all three tumors. The estrogen-dependent tumors (MCF-7, ZR 75-1), however, had more desmosomes, intermediate-sized microfilaments and collagen than the estrogen-independent tumor (MDA-MB 231). When the ultrastructure of the three human tumors was compared to the hormone-dependent, DMBA-induced rat mammary carcinoma and to the normal lactating rat mammocytes, the following observations were evident: a) the estrogen-dependent human tumors closely resembled the normal rat tissue in the distribution of desmosomes and collagen, b) the rat mammary carcinoma differed from both the estrogen-dependent and -independent human tumors, in having milk protein, milk fat globules and intense lactoperoxidase activity. The results indicate that these hormone-dependent and -independent human mammary tumors maintained in athymic nude mice differ markedly in their ultrastructure from the lactating rat mammocytes and the rat DMBA-induced mammary carcinoma.
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PMID:Similarities and differences in the ultrastructure of two hormone-dependent and one independent human breast carcinoma grown in athymic nude mice: comparison with the rat DMBA-induced tumor and normal secretory mammocytes. 643 51

Friend erythroleukemia cells (FLC), serially passaged in vitro or by intraperitoneal injection in DBA/2 mice, exhibit markedly different tumorigenicity and capacity to metastasize. We have attempted to determine whether the differences in tumorigenicity between these two lines of FLC were correlated with any biochemical changes in their cell membranes. Although consistent modifications of FLC membrane gangliosides were detected after FLC multiplied in the peritoneum, the pattern of FLC gangliosides was not a stable characteristic and did not correlate with tumorigenicity. In contrast, analysis of FLC membrane glycoproteins by cell surface labelling techniques (i.e., galactose-oxidase-borohydride techniques and polyacrylamide gel electrophoresis-fluorography) or by metabolic labelling of glycoproteins with 3H-galactose, revealed consistent differences in the high MW region of the gels between parental in vitro passaged FLC (either 745 or 3Cl-8 cells) and clones derived from in vivo passaged cells. No significant differences in the membrane proteins were detected between in vitro and in vivo passaged FLC when lactoperoxidase-catalyzed iodination and polyacrylamide gel electrophoresis-autoradiography were used. It is seen that repeated in vivo passages of FLC resulted in the appearance of different patterns of membrane glycoproteins and that these changes appeared to be associated consistently with the capacity of these cells to grow as tumor ascites and to metastasize to the liver and spleen.
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PMID:Biologic and biochemical differences between in vitro and in vivo passaged Friend erythroleukemia cells. II. Changes in cell surface glycoproteins associated with a highly malignant phenotype. 648 Jan 57

An xenogeneic rat anti-mouse T-cell serum, designated RAT*, has been shown to block the cytolytic activity of cytotoxic T lymphocytes (CTL) at a postbinding step. RAT* serum or the IgG fraction was extensively absorbed with the target cell, P815, a DBA mastocytoma, and used with or without further absorption to immunoprecipitate specific molecules from radiolabeled membrane extracts of CTL derived from either in vivo-allosensitized mice or from cytotoxic clones maintained in in vitro cultures. Cell surface sialic acid residues were labeled by oxidation with sodium periodate (NaIO4) and reduction with tritiated sodium borohydride ([3H]NaBH4). Alternatively, cell surface proteins were labeled with 125I by lactoperoxidase-catalyzed iodination. Nonidet P-40 (NP-40)-solubilized radiolabeled membranes were then immunoprecipitated with RAT* serum and analyzed by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (PAGE). Three membrane-associated molecules of 95,000, 140,000 and 180,000 Mr were found by such analysis. The sensitivity of these three molecules to trypsinization and their susceptibility to labeling with [3H]NaBH4 suggested that they are glycoproteins. Moreover, when RAT* serum or the IgG fraction was absorbed with various cell types, its ability to immunoprecipitate the three molecules correlated with its ability to block cytolysis. Adsorption of RAT* serum with CTL, but not with nonimmune thymocytes, significantly reduced the ability of RAT* serum to inhibit cytotoxicity and to immunoprecipitate the 95k, 140k, and 180k molecules. Thus, these findings suggest that one or more of these cell surface molecules of CTL may be involved in the cytolytic process.
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PMID:Studies on the induction and expression of T-cell-mediated immunity. XIII. Membrane-associated antigens of cytotoxic T lymphocytes involved in cytotoxicity. 660 Sep 72

Bloodstream trypomastigote and culture procyclic (insect midgut) forms of a cloned T. rhodesiense variant (WRAT at 1) were tested for agglutination with the lectins concanavalin A (Con A), phytohemagglutinin P (PP), soybean agglutinin (SBA), fucose binding protein (FBP), wheat germ agglutinin (WGA), and castor bean lectin (RCA). Fluorescence-microscopic localization of lectin binding to both formalin-fixed trypomastigotes and red cells was determined with fluorescein isothiocyanate (FITC)-conjugated Con A, SBA, FBP, WGA, RCA, PNA (peanut agglutinin), DBA (Dolichos bifloris), and UEA (Ulex europaeus) lectins. Electron microscopic localization of lectin binding sites on bloodstream trypomastigotes was accomplished by the Con A-horseradish peroxidase-diamino-benzidine (HRP-DAB) technique, and by a Con A-biotin/avidin-ferritin method. Trypomastigotes, isolated by centrifugation or filtration through DEAE-cellulose or thawed after cryopreservation, were agglutinated by the lectins Con A and PP with agglutination strength scored as Con A greater than PP. No agglutination was observed in control preparations or with the lectins WGA, FBA or SBA. Red cells were agglutinated by all the lectins tested. Formalin-fixed bloodstream trypomastigotes bound FITC-Con A and FITC-RCA but not FITC-WAG, -SBA, -PNA, -UEA or -DBA lectins. All FITC-labeled lectins bound to red cells. Con A receptors, visualized by Con A-HRP-DAB and Con A-biotin/avidin-ferritin techniques, were distributed uniformly on T. rhodesiense bloodstream forms. No lectin receptors were visualized on control preparations. Culture procyclics lacked a cell surface coat and were agglutinated by Con A and WGA but not RCA, SBA, PP and FBP. Procyclics were not agglutinated by lectins in the presence of competing sugar at 0.25 M.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Trypanosoma rhodesiense bloodstream trypomastigote and culture procyclic cell surface carbohydrates. 668 36

Monoclonal antibodies reactive with NIH/3T3 cell surface antigens were obtained from hybridomas of murine myeloma cells fused to spleen cells of rats immunized with NIH/3T3 cell plasma membranes. Four of the antibodies, of forty that have been studied, appeared to react with allospecific antigenic determinants: they bound to NIH/3T3 cells but not to BALB/ 3T3 cells. Each of these four antibodies immunoprecipitated a glycoprotein of about 80,000 daltons that migrated to an isoelectric point of about pH 5.0. Polypeptides of identical molecular weight and isoelectric points, and yielding the same proteolytic cleavage fragments, were present in BALB/3T3 cells, but were not antigenically reactive. The 80,000-dalton glycoprotein was a major constituent of the plasma membrane. It was a predominant lactoperoxidase iodinated component of intact NIH/3T3 cells, and saturation binding of 125I-labeled antibody indicated that there were about 10(6) antigenic sites/cell. Studies of the distribution of the immunoreactive glycoprotein among different strains of mice confirmed the polymorphic expression of the determinant: Spleen cells of BALB/c, DBA/1, DBA/2, and CBA mice did not bind anti-80,000-dalton glycoprotein monoclonal antibodies, whereas spleen cells of a large number of other strains of mice were positive for antibody-binding. The antigenic reactivity varied markedly among different cell lines and was greatest with the NIH/3T3 mouse embryo fibroblast, G8-1 Swiss Webster myoblast, and IC-21 SV40-transformed C57BL/6 mouse peritoneal macrophage. The properties of the 80,000-dalton glycoprotein characterized this molecule as a new cell surface differentiation alloantigen of murine mesenchymal cells.
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PMID:Murine cell surface glycoproteins. Characterization of a major component of 80,000 daltons as a polymorphic differentiation antigen of mesenchymal cells. 678 57

In the hormonally responsive 7,12-dimethylbenz(a)anthracene (DMBA)- or N-nitrosomethylurea (NMU)-induced mammary carcinomas, regulatory mechanisms have been altered such that these tumors retain their hormonal dependence for growth but possess only a limited ability to synthesize the mammary gland-specific milk proteins. Quantitation of casein mRNA levels revealed that very low levels of casein messenger RNA (mRNA) were expressed in both the DMBA- and NMU-induced tumors growing in virgin animals (0.1 to 0.4% of the maximally induced 8-day-lactating mammary gland). Growth of DMBA-induced tumors in pregnant rats and the treatment of NMU-induced tumor-bearing animals with thioproperazine indicated that the tumor casein mRNA levels were hormone inducible (3.4- and 2.1-fold for the DMBA- and NMU-induced tumors, respectively). However, casein mRNA levels were still only 1 to 2% of those found in the normal mammary gland under the same hormonal environment. Localization of the casein-synthesizing cells in the DMBA-induced tumors by peroxidase-antiperoxidase staining and a specific casein antiserum indicated that, in both control and hormone-treated tumors, the vast majority of cells (greater than 95%) were unstable to synthesize casein. The hormonal induction of casein mRNA sequences could be correlated with an increase in the number of cells synthesizing casein, which appeared as small clusters of cells throughout the tumors. Therefore, the loss of hormone-regulated differentiated function in these tumors, which maintained hormone-dependent growth, suggests the presence of a defective regulatory mechanism beyond the level of the hormone-receptor-complex.
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PMID:Hormonal induction of casein gene expression limited to a small subpopulation of 7,12-dimethylbenz(a)anthracene-induced mammary tumor cells. 680 Jun 52

The incidence of DMBA-induced mammary carcinomas in Sprague-Dawley rats depends upon their previous reproductive histories. Young virgin rats (YV) are highly susceptible to the carcinogen, while old virgin rats (OV) are less susceptible, and parous rats (P) are resistant. The authors performed endocrinologic studies in these three groups of rats in order to determine whether the different susceptibility to carcinogenesis, according to the reproductive history, is or is not related to the hormonal milieu. The pituitary, the ovaries, the adrenals, and the mammary glands were processed for light microscopy. Pituitary prolactin (PRL), follicle-stimulating hormone, and luteinizing hormone cells were immunostained by peroxidase-antiperoxidase and quantitated with an image analyzer. Radioimmunoassays of serum and pituitary PRL and serum estradiol were also done. The results showed no differences in the hormonal milieu of YV, OV, and P rats at the time of carcinogen treatment. Several changes were observed after DMBA administration, the most conspicuous being 1) hyperplasia of pituitary PRL cells, 2) high serum PRL levels, 3) nodular hyperplasia of the adrenal cortex, 4) high serum estradiol levels, and 5) lack of adrenal necrosis in P rats and some OV rats. These modifications did not correlate with the degree of susceptibility of YV, OV, and P rats to carcinogenesis, supporting the concept of the importance of the mammary gland differentiation at the moment of carcinogen administration. (Am J Pathol 1982, 109:47-56).
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PMID:Endocrinologic milieu and susceptibility of the rat mammary gland to carcinogenesis. 681 28


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