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)

'Golgi-like' labeling of anterior thalamic neurons was achieved by injecting horseradish peroxidase dissolved in dimethylsulfoxide (DMSO) into the striatum of the rabbit. Forty-eight hours after injection, elements of the presumed thalamocortical population of anterior thalamic neurons are diffused filled with HRP to the extent that their dendritic arborizations, and even spinous processes, can be readily characterized. Ultrastructurally, these solidly labeled thalamic neurons are seen to contain large, irregular electron dense granules dispersed within a moderately electron dense cytoplasm.
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PMID:Morphology and ultrastructure of anterior thalamic neurons solidly labeled with horseradish peroxidase. 737 62

Rat peritoneal cells were made to bind test particles of five different species: immunoglobulin-coated sheep red cells (IGSRC), glutaraldehyde-treated sheep red cells (GSRC), leishmania, latex beads and tumour cells. The dependence of binding on various physicochemical parameters was studied: the binding of latex or leishmania resisted cold (4 degrees), azide, cytochalasin B, ethyleneglycol and dimethylsulphoxide (DMSO). The binding of IGSRC resisted cold and azide, but it was inhibited by cytochalasin B, ethyleneglycol and DMSO. The binding of GSRC was inhibited by cold, azide and ethyleneglycol, but not by cytochalasin B and DMSO. The binding of tumour cells was inhibited by azide, cytochalasin B, ethyleneglycol and DMSO. An attempt was made to saturate selectively some adhesive sites of macrophage membranes: glutaraldehyde-treated bovine albumin (GBSA) inhibited the ingestion of latex and GSRC, not leishmania and IGSRC, whereas a crude leishmania extract (CLE) inhibited the ingestion of all tested particles except latex. Antigen-antibody complexes inhibited the ingestion of IGSRC and leishmania, not latex and GSRC. Rat macrophages were made to bind radio-iodinated GBSA (GIBSA). The uptake of glutaraldehyde-treated albumin was proportional to the amount of substrate the cells were incubated with over a wide concentration range. This uptake was not a result of endocytosis, and it was far more efficient than that of peroxidase. Macrophage-particle interaction was studied with electron microscopy. The binding of IGSRC and leishmania to macrophages involved large areas where the interacting membranes were separated by a low density gap of constant width. The interaction of GSRC and latex with macrophages was much more patchy and irregular. Further, no redistribution of the macrophage surface polysaccharides seemed associated with the binding of GSRC. It was concluded that several different mechanisms and different membrane adhesive structures are involved in non-specific recognition by macrophages. Further, non-specific binding sometimes requires an active cell participation. Several testable hypotheses are described, which suggest further experiments in order to obtain a fuller insight into the mechanism of rosette formation.
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PMID:Non-specific binding by macrophages: existence of different adhesive mechanisms and modulation by metabolic inhibitors. 746 2

Treatment of immature 21-day-old female Sprague-Dawley rats with 17 beta-estradiol (E2) (0.5 microgram/rat) caused a significant increase in uterine wet weight, DNA synthesis, progesterone receptor (PR) binding, and peroxidase activity. At doses as high as 40 mg/rat, the bioflavonoid naringenin did not cause a significant increase in any of these E2-induced responses. However, in rats cotreated with E2 (0.5 microgram/rat) plus naringenin (30 mg/rat); there was a significant decrease in E2-induced uterine wet weight, DNA synthesis, PR binding, and peroxidase activity, indicating that naringenin exhibits antiestrogenic activity in the immature rodent uterus. The binding of uterine nuclear extracts to a 32P-labeled estrogen responsive element (ERE) or progesterone responsive element (PRE) was determined using gel electrophoretic band shift assays. Incubation of [32P]ERE with uterine nuclear extracts from rats treated with naringenin or E2 resulted in the formation of estrogen receptor (ER):ERE complexes; a higher mobility complex was prominent in the extracts from E2-treated rats, whereas a lower mobility complex was observed using nuclear extracts from naringenin-treated animals. There was a significant decrease in the intensity of the E2-induced complex using nuclear extracts from rats treated with E2 plus naringenin. In contrast, transformed cytosol from control rats gave an intense ER:ERE complex, whereas the intensity of the band was decreased markedly using transformed uterine cytosol from treated rats. Formation of a PR:PRE complex was also determined using transformed uterine cytosol. Cytosol from E2-treated rats gave an intense retarded band, whereas only weak bands were observed using cytosols from DMSO- (solvent), naringenin-, or naringenin plus E2-treated cells. The results of in vitro studies showed that 1 nM E2 increased (3- to 4-fold) the growth of MCF-7 human breast cancer cells, whereas 1-1000 nM naringenin had no effect on cell proliferation. In cells cotreated with 1 nM E2 plus 1000 nM naringenin, there was a significant decrease in E2-induced cell growth. In MCF-7 cells transiently transfected with a pS2 promoter-regulated luciferase reporter gene, naringenin exhibited weak estrogenic activity. In cells cotreated with 0.1 or 1.0 microM naringenin plus 1 nM E2, naringenin inhibited E2-induced luciferase activity. The results of these studies confirmed that naringenin is a weak estrogen that also exhibits partial antiestrogenic activity in the female rat uterus and MCF-7 human breast cancer cells.
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PMID:Naringenin: a weakly estrogenic bioflavonoid that exhibits antiestrogenic activity. 750

We have assessed the properties of three intracellular markers, horseradish peroxidase, biocytin/Neurobiotin, and Lucifer Yellow, and have compared their usefulness as neuronal markers for light and electron microscopic visualization. Neurons in the acute slice preparation of rat hippocampus were filled with one of these markers, and the marker was converted to an optical and electron-dense reaction product. Dimethylsulfoxide (DMSO) greatly facilitated penetration of recognition reagents while preserving membrane integrity. The markers were compared with respect to injection parameters, mobility and recognition, stability and visibility, and ultrastructural clarity. Horseradish peroxidase (HRP)-labeled neurons, recognized histochemically with diaminobenzedine (DAB), were easily visualized by the density of the DAB reaction product; however, the electron density was often so great as to obscure ultrastructural details. Biocytin (BC)-/Neurobiotin (NB)-labeled neurons were recognized by avidin-HRP, followed by histochemical localization of HRP with DAB. The optically dense reaction product gave complete visualization of the soma and processes at the light microscopic level. The electron density was homogeneously distributed throughout the cell, so that ultrastructural features were easily identified. Lucifer Yellow (LY), a fluorescent marker, was converted to an optical and electron-dense reaction product via immunocytochemical staining with a rabbit anti-LY antibody, followed by goat anti-rabbit IgG-HRP and DAB histochemical localization. Similar to BC/NB, the reaction product was evenly dispersed, providing good light microscopic and ultrastructural clarity. Under our experimental conditions, BC/NB and LY were superior markers that could be used routinely to label neurons, and give excellent visualization not only at the light but also at the electron microscopic level.
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PMID:Electron microscopy of intracellularly labeled neurons in the hippocampal slice preparation. 767 92

Human neutrophils activated by PMA were found to induce the formation of a nitroxide radical from DFO. The presence of SOD was necessary to permit the formation of the DFO radical. The inactive phorbol ester did not induce DFO radical, and DL-sphinganine suppressed the radical produced by the active phorbol ester. Other cell stimuli (Zymocel and the chemotactic peptide) also induced the formation of the DFO radical, although radical concentration was very much lower than with PMA. Participation of NO, OH or 1O2 was ruled out by the inability of NG-methyl-L-arginine, NG-nitro-L-arginine, DMSO, mannitol, histidine, and methionine to inhibit the formation of DFO radical produced by PMA-activated cells. Furthermore, PMA-activated cells did not produce detectable levels of NO2-, a stable oxidation product of NO, and D2O, which enhances the lifetime of singlet oxygen, did not modify the intensity or the lifetime of DFO radical. The involvement of cell MPO was suggested by the inhibition of the DFO radical observed after treatment with catalase or with antihuman MPO antibodies. Also, HOCl was found to induce the DFO radical in cell-free reactions, but our data indicate that the reaction leading to DFO radical formation by neutrophils involves the reduction of MPO compound II back to the active enzyme (ferric-MPO). Anti-inflammatory drugs strongly increased the DFO radical produced by activated neutrophils. On the contrary, none of these drugs was able to increase the DFO radical produced by HOCl. Histidine and methionine that inhibited the DFO radical intensity in cell-free reactions, were shown to act directly on HOCl. Experiments with MPO-H2O2 in SOD- and Cl(-)-free conditions showed the formation of DFO radical and confirmed the hypothesis of the involvement of compound II. The conversion of compound II to ferric MPO by DFO optimized the enzymatic activity of neutrophils, and in the presence of monochlorodimedon (compound II promoting agent) we measured an increased HOCl production. When DFO was modified by conjugation with hydroxyethyl starch, it lost the ability to produce the radical either by neutrophils or by MPO-H2O2 and did not increase HOCl production. The inability of these DFO derivatives to produce potentially toxic species might explain their reported lower toxicity in vivo.
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PMID:Oxidation of desferrioxamine to nitroxide free radical by activated human neutrophils. 768 74

The human leukemic cell line LAMA-84 was established and characterized as an erythromegakaryocytic cell line. In the present study we show that these cells can differentiate in estrone-treated athymic mice and give rise to an erythroeosinophilic cell line (LAMA-87). This new cell line expressed glycoporin A, alpha beta and gamma globin chain mRNA but also eosinophilic peroxidase. Hemin slightly increased the total hemoglobin production of the cells and phorbol diester (TPA), dimethyl sulfoxide (DMSO) and sodium butyrate (SB) increased the expression of megakaryocytic markers (gpIIb/IIIa complex). When inoculated into non-treated athymic mice, LAMA-87 cells can differentiate to give rise to eosinomonocytic cells (LAMA-88). This new cell line expresses eosinophilic peroxidase, Luxol fast blue stain and synthesizes lysozyme. Depending on the inducer used, LAMA-88 can differentiate along a monocytic lineage (TPA, DMSO, SB and vitamin D3). These three LAMA cell lines should be useful in further studies of the molecular regulation of the pluripotent cell commitment and may provide a model for the understanding of human hematopoiesis.
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PMID:Selection and characterization of an erythroeosinophilic subclone (LAMA-87) and an eosinophilic subclone (LAMA-88) from the multipotential cell line LAMA-84. 799 72

A myeloid-antigen-positive acute lymphoblastic leukemia (My+ALL) cell line (EU-1) was established from the bone marrow cells of a child with apparent ALL. By morphology, cytochemistry and fluorescent-antibody phenotyping, EU-1 cells appeared to be lymphoblastic (L1 morphology, TdT+, CD10+, CD19+). However, by a sensitive immunocytochemical assay, EU-1 cells additionally displayed several myeloid antigens (CD13, CD14, CD33) not detected by flow-cytometry. Furthermore, EU-1 cells were cytochemically and immunocytochemically negative for myeloperoxidase (MPO) but positive for MPO mRNA by Northern blot analysis. After incubation with dimethylsulfoxide (DMSO), myeloid cell surface antigens were detected on EU-1 cells by flow cytometry, and a marked decrease in MPO mRNA expression was observed. These results demonstrate that EU-1 is a unique ALL cell line representing a significant subset of pediatric ALL patients who also express myeloid antigens and have poor prognosis.
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PMID:Characterization of a myeloperoxidase mRNA(+) acute lymphoblastic leukemia cell line (EU-1/ALL) established from a child with an apparent case of ALL. 815 61

The nature of the compartmentalization of catalase in human myeloid cells is an unresolved issue. Using a rabbit polyclonal antibody specific for catalase, indirect immunocytofluorescence of immature leukemic promyelocytes (HL-60 cells) showed a pattern of small, sharp, punctate staining in the cytoplasm of all cells, while mature neutrophils showed a larger diffuse, flocculent pattern of cytoplasmic staining. Differential centrifugation of nitrogen cavitates of HL-60 cells indicated that the putative catalase-containing compartment was relatively fragile compared with the compartment(s) that contained myeloperoxidase (MPO), beta-hexosaminidase, beta-glucuronidase, and lysosomal alpha-mannosidase activities. Parallel studies using dimethylsulfoxide (DMSO)-induced HL-60 cells and mature neutrophils showed that, in the course of differentiation, there was an apparent shift in the localization of catalase from the granule fraction to the cytosolic fraction. Percoll-sucrose density gradient centrifugation of HL-60 cell cavitates showed a catalase-containing compartment with a mean peak density (1.05 g/mL) significantly lower than that of the major myeloperoxidase-containing compartment (1.08 g/mL); in mature neutrophils, catalase activity comigrated with lactate dehydrogenase (LDH) activity. Catalase in isolated fractions was protected from proteolysis in the absence, but not in the presence, of 0.1% Triton X-100. Digitonin titration experiments confirmed the compartmentalized nature of catalase in immature HL-60 cells and were consistent with a cytosolic localization in mature neutrophils. Ultrastructural localization of catalase by Protein A-gold immunocytochemistry demonstrated four to six catalase-containing compartments in all HL-60 cell profiles. In mature neutrophils, catalase was localized primarily in the cytoplasmic matrix, although in fewer than 2% of the cell profiles, one to two catalase-containing compartments were observed. The changes in catalase localization that occur during myeloid differentiation appear to be similar to the changes that occur during erythroid and megakaryocytic differentiation, and may have potential clinical significance in the classification of acute leukemia and in the development of drug resistance.
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PMID:Changes in the localization of catalase during differentiation of neutrophilic granulocytes. 816 45

UDP-glucuronosyltransferases (UGTs) catalyze the glucuronidation and elimination of putative tobacco carcinogens such as benzo[a]pyrene (B[a]P) and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), which may reduce competing bioactivation and toxicity. B[a]P-initiated cytotoxicity and micronucleus formation, believed to reflect carcinogenic initiation, are enhanced in UGT-deficient rat fibroblasts, and UGTs may provide similar genoprotection against NNK. Using skin fibroblasts from wild-type UGT-normal (+/+) and congenic heterozygous (+/j) and homozygous (j/j) UGT-deficient rats, this study evaluated NNK in relation to B[a]P with respect to the mechanism of genotoxicity, evidenced by micronucleus formation, and genoprotection++ by UGTs. Molecular mechanisms were determined by changes in B[a]P- and NNK-initiated micronucleus formation when cells were incubated with the antioxidative enzyme superoxide dismutase (1680 IU/ml), inhibitors of cytochrome P450 (1 mM 1-aminobenzotriazole) and peroxidases (1-aminobenzotriazole; 40 microM eicosatetraynoic acid), and inducers of CYP1A1/2(10 nM 2,3,7,8-tetrachlorodibenzo-p-dioxin) and peroxidases [2,3,7,8-tetrachlorodibezo-p-dioxin; 0.625 ng/ml (0.0367 nM) interleukin 1alpha; 1 microM 12-0-tetradecanoylphorbol-13-acetate]. In +/+ fibroblasts, NNK and B[a]P initiated concentration-dependent, respective maximum 2.7-fold and 1.7-fold increases over DMSO controls in micronucleus formation (P < 0.05), with 10 microM NNK being 2.4-fold more genotoxic than B[a]P (P < 0.05). In both +/j and j/j UGT-deficient cells, micronuclei initiated by NNK and B[a]P each were over 2-fold higher than that in +/+ UGT normal cells (P < 0.05). Both NNK- and B[a]P-initiated micronuclei were decreased by superoxide dismutase and cytochrome P450/peroxidase inhibitors, while only that initiated by B[a]P was enhanced, up to 2.4-fold, by inducers, of which only interleukin 1alpha was effective in all UGT phenotypes (P < 0.05). These results provide the first evidence that: (a) UGTs may be genoprotective for NNK, with even heterozygous UGT deficiencies being toxicologically critical; and (b) peroxidase-catalyzed bioactivation, reactive oxygen species, and molecular target oxidation may contribute differentially to the genotoxicity of both NNK and B[a]P.
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PMID:Genoprotection by UDP-glucuronosyltransferases in peroxidase-dependent, reactive oxygen species-mediated micronucleus initiation by the carcinogens 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone and benzo[a]pyrene. 860 97

It has been shown that dimethyl sulfoxide competes with the enzyme substrate towards horseradish peroxidase compound I, but probably not towards horseradish peroxidase compound II. Dimethyl sulfoxide may hinder the reaction of superoxide with horseradish peroxidase compound II by modifying heme center. In this connection dimethyl sulfoxide is not recommended as a solvent in catalytic studies of horseradish peroxidase.
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PMID:Dimethyl sulfoxide rather than superoxide is the reactive species in horseradish peroxidase--KO2/dimethyl sulfoxide system. 862 84


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