Searched for: subject%3A%22Cytochrome%255C%2BP%255C-450%255C%2BEnzyme%255C%2BSystem%22
(1 - 20 of 49)
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Price, R.J. (author), Scott, M.P. (author), Giddings, A.M. (author), Walters, D.G. (author), Stierum, R.H. (author), Meredith, C. (author), Lake, B.G. (author), TNO Kwaliteit van Leven (author)1. The objective of this study was to investigate the effects of four food chemicals, namely butylated hydroxytoluene (BHT), curcumin (CC), propyl gallate (PG) and thiabendazole (TB), on cytochrome P450 (CYP) forms in cultured human hepatocytes. 2. Treatment of human hepatocytes for 72 h with 2-200 μM TB produced concentration-dependent...article 2008
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Ruijssenaars, H.J. (author), Sperling, E.M.G.M. (author), Wiegerinck, P.H.G. (author), Brands, F.T.L. (author), Wery, J. (author), de Bont, J.A.M. (author), TNO Kwaliteit van Leven (author)A steroid 15β-hydroxylating whole-cell solvent tolerant biocatalyst was constructed by expressing the Bacillus megaterium steroid hydroxylase CYP106A2 in the solvent tolerant Pseudomonas putida S12. Testosterone hydroxylation was improved by a factor 16 by co-expressing Fer, a putative Fe-S protein from Bacillus subtilis. In addition, the...article 2007
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Jeurissen, S.M.F. (author), Claassen, F.W. (author), Havlik, J. (author), Bouwmans, E.E. (author), Cnubben, N.H.P. (author), Sudhölter, E.J.R. (author), Rietjens, I.M.C.M. (author), van Beek, T.A. (author), TNO Kwaliteit van Leven (author)An on-line HPLC screening method for detection of inhibitors of human cytochrome P450 1A2 in extracts was developed. HPLC separation of extracts is connected to a continuous methoxyresorufin-O-demethylation (MROD) assay in which recombinant human P450 1A2 converts methoxyresorufin to its fluorescent metabolite resorufin. The system was tested...article 2007
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Jeurissen, S.M.F. (author), Punt, A. (author), Boersma, M.G. (author), Bogaards, J.J.P. (author), Fiamegos, Y.C. (author), Schilter, B. (author), van Bladeren, P.J. (author), Cnubben, N.H.P. (author), Rietjens, I.M.C.M. (author), TNO Kwaliteit van Leven (author)Human cytochrome P450 enzymes involved in the bioactivation of estragole to its proximate carcinogen 1′-hydroxyestragole were identified and compared to the enzymes of importance for 1′-hydroxylation of the related alkenylbenzenes methyleugenol and safrole. Incubations with Supersomes revealed that all enzymes tested, except P450 2C8, are...article 2007
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Kienhuis, A.S. (author), Wortelboer, H.M. (author), Maas, W.J. (author), van Herwijnen, M. (author), Kleinjans, J.C.S. (author), van Delft, J.H.M. (author), Stierum, R.H. (author), TNO Kwaliteit van Leven (author)A rapid decline of cytochrome P450 (CYP450) enzyme activities remains a drawback of rat hepatocyte-based in vitro cultures. Consequently, judgment of the toxic potential of compounds that need bioactivation by CYP450s may not be adequate using this model. In the present study, an improved hepatocyte-based in vitro system was developed with...article 2007
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Jeurissen, S.M.F. (author), Bogaards, J.J.P. (author), Boersma, M.G. (author), ter Horst, J.P.F. (author), Awad, H.M. (author), Fiamegos, Y.C. (author), van Beek, T.A. (author), Alink, G.M. (author), Sudhölter, E.J.R. (author), Cnubben, N.H.P. (author), Rietjens, I.M.C.M. (author), TNO Kwaliteit van Leven (author)In vitro studies were performed to elucidate the human cytochrome P450 enzymes involved in the bioactivation of methyleugenol to its proximate carcinogen 1′-hydroxymethyleugenol. Incubations with Supersomes, expressing individual P450 enzymes to a high level, revealed that P450 1A2, 2A6, 2C9, 2C19, and 2D6 are intrinsically able to 1′...article 2006
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Parnham, M.J. (author), Bogaards, J.J.P. (author), Schrander, F. (author), Schut, M.W. (author), Orešković, K. (author), Mildner, B. (author), TNO Kwaliteit van Leven (author)PLD-118 is a novel, oral antifungal drug, under development for the treatment of Candida infections. Possible metabolism of PLD-118 by rat, dog and human S9 liver homogenates and inhibition of human cytochrome P450 (CYP) enzymes were investigated. PLD-118 (10 and 100 μm) incubated for 0-60 min with S9 fractions and NADPH was determined by HPLC,...article 2005
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Price, R.J. (author), Scott, M.P. (author), Walters, D.G. (author), Stierum, R.H. (author), Groten, J.P. (author), Meredith, C. (author), Lake, B.G. (author), TNO Voeding (author)The effect of thiabendazole (TB) on some rat hepatic xenobiotic metabolising enzymes has been investigated. Male Sprague-Dawley rats were fed control diet or diets containing 102-5188 ppm TB for 28 days. As a positive control for induction of hepatic xenobiotic metabolism, rats were also fed diets containing 1457 and 10,155 ppm butylated...article 2004
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Jeurissen, S.M.F. (author), Bogaards, J.J.P. (author), Awad, H.M. (author), Boersma, M.G. (author), Brand, W. (author), Fiamegos, Y.C. (author), van Beek, T.A. (author), Alink, G.M. (author), Sudhölter, E.J.R. (author), Cnubben, N.H.P. (author), Rietjens, I.M.C.M. (author), TNO Voeding (author)In the present study, the cytochrome P450 mediated bioactivation of safrole to its proximate carcinogenic metabolite, 1′-hydroxysafrole, has been investigated for the purpose of identifying the human P450 enzymes involved. The 1′-hydroxylation of safrole was characterized in a variety of in vitro test systems, including Supersomes, expressing...article 2004
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Artola-Garicano, E. (author), Sinnige, T.L. (author), van Holsteijn, I. (author), Vaes, W.H.J. (author), Hermens, J.L.M. (author)In the current study, the bioconcentration behavior and acute toxicity of two polycyclic musks, Tonalide® 7-acetyl-1,1,3,4,4,6,-hexamethyl-1,2,3,4,-tetrahydronaphthalene (AHTN) and Galaxolide® 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexa-methyl-cyclopenta[γ]-2- benzopyran (HHCB), were studied in two benthic organisms. Polycyclic musks are frequently...article 2003
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Tryfonidou, M.A. (author), Stevenhagen, J.J. (author), van den Bemd, G.J.C.M. (author), Oosterlaken-Dijksterhuis, M.A. (author), Deluca, H.F. (author), Mol, J.A. (author), van den Brom, W.E. (author), van Leeuwen, J.P.T.M. (author), Hazewinkel, H.A.W. (author), Centraal Instituut voor Voedingsonderzoek TNO (author)Hormonal regulation of calcium (Ca) absorption was investigated in a cholecalciferol (vitamin D3)supplemented group (hVitD) vs. a control group (cVitD) of growing Great Danes (100 vs. 12.5 μg vitamin D3/kg diet). Although Ca intakes did not differ, fractional Ca absorption was significantly lower in the hVitD group than in the cVitD group. There...article 2002
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Post, S.M. (author), Duez, H. (author), Gervois, P.P. (author), Staels, B. (author), Kuipers, F. (author), Princen, H.M.G. (author), Gaubius Instituut TNO (author)Fibrates are hypolipidemic drugs that affect the expression of genes involved in lipid metabolism by activating peroxisome proliferator-activated receptors (PPARs). Fibrate treatment causes adverse changes in biliary lipid composition and decreases bile acid excretion, leading to an increased incidence of cholesterol gallstones. In this study,...article 2001
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Bogaards, J.J.P. (author), Hissink, E.M. (author), Briggs, M. (author), Weaver, R. (author), Jochemsen, R. (author), Jackson, P. (author), Bertrand, M. (author), van Bladeren, P. (author), Centraal Instituut voor Voedingsonderzoek TNO (author)A strategy is presented to predict interindividual variation in drug plasma levels in vivo by the use of physiologically based pharmacokinetic modeling and human in vitro metabolic parameters, obtained through the combined use of microsomes containing single cytochrome P450 enzymes and a human liver microsome bank. The strategy, applied to the...article 2000
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Renwick, A.B. (author), Watts, P.S. (author), Edwards, R.J. (author), Barton, P.T. (author), Guyonnet, I. (author), Price, R.J. (author), Tredger, J.M. (author), Pelkonen, O. (author), Boobis, A.R. (author), Lake, B.G. (author), Centraal Instituut voor Voedingsonderzoek TNO TNO Voeding (author)The maintenance of the major hepatic cytochrome P450 (CYP) enzymes has been studied in precision-cut human liver slices cultured for up to 72 h in supplemented RPMI 1640 medium. The relative apoprotein levels of 11 CYP enzymes were determined using a panel of antipeptide antibodes. In addition, 7-ethoxyresorufin O-deethylase, tolbutamide...article 2000
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Hissink, A.M. (author), Wormhoudt, L.W. (author), Sherratt, P.J. (author), Hayes, J.D. (author), Commandeur, J.N.M. (author), Vermeulen, N.P.E. (author), van Bladeren, P.J. (author), Centraal Instituut voor Voedingsonderzoek TNO TNO Voeding (author)A physiologically-based pharmacokinetic (PB-PK) model was developed for ethylene dibromide (1,2-dibromoethane, EDB) for rats and humans, partly based on previously published in vitro data (Ploemen et al., 1997). In the present study, this PB-PK model has been validated for the rat. In addition, new data were used for the human class ΘGST T1-1....article 2000
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Kappers, W.A. (author), van Och, F.M.M. (author), de Groene, E.M. (author), Horbach, G.J. (author), Centraal Instituut voor Voedingsonderzoek TNO (author)Three different in vitro mutation assays were used to investigate the involvement of cytochrome P450 enzymes in the activation of the nitro- polycyclic aromatic hydrocarbons (nitroPAHs) 1-nitropyrene and 2- nitrofluorene and their reduced metabolites amino-polycyclic aromatic hydrocarbons (aminoPAHs) 1-aminopyrene and 2-aminofluorene....article 2000
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Centraal Instituut voor Voedingsonderzoek TNO TNO Voeding (author), van der Werf, M.J. (author), Keijzer, P.M. (author), van der Schaft, P.H. (author)Xanthobacter sp. C20 was isolated from sediment of the river Rhine using cyclohexane as sole source of carbon and energy. Xanthobacter sp. C20 converted both enantiomers of limonene quantitatively into limonene-8,9-epoxide, a not previously described bioconversion product of limonene. With (4R)-limonene, (4R,8R)-limonene-8,9-epoxide was formed...article 2000
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van Iersel, M.L.P.S. (author), Verhagen, H. (author), van Bladeren, P.J. (author), Centraal Instituut voor Voedingsonderzoek TNO (author)The fact that dietary compounds influence the susceptibility of human beings to cancer, is widely accepted. One of the possible mechanisms that is responsible for these (anti)carcinogenic effects is that dietary constituents may modulate biotransformation enzymes, thereby affecting the (anti)carcinogenic potential of other compounds. This...article 1999
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Gaubius instituut TNO (author), Post, S.M. (author), Twisk, J. (author), van der Fits, L. (author), de Wit, E.C.M. (author), Hoekman, M.F.M. (author), Mager, W.H. (author), Princen, H.M.G. (author)Lipoproteins may supply substrate for the formation of bile acids, and the amount of hepatic cholesterol can regulate bile-acid synthesis and increase cholesterol 7α-hydroxylase expression. However, the effect of lipoprotein cholesterol on sterol 27-hydroxylase expression and the role of different lipoproteins in regulating both enzymes are not...article 1999
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Gaubius instituut TNO (author), Koopen, N.R. (author), Post, S.M. (author), Wolters, H. (author), Havinga, R. (author), Stellaard, F. (author), Boverhof, R. (author), Kuipers, F. (author), Princen, H.M.G. (author)Effects of 17alpha-ethinylestradiol (EE) on the neutral and acidic biosynthetic pathways of bile salt (BS) synthesis were evaluated in rats with an intact enterohepatic circulation and in rats with long-term bile diversion to induce BS synthesis. For this purpose, bile salt pool composition, synthesis of individual BS in vivo, hepatic activities...article 1999
Searched for: subject%3A%22Cytochrome%255C%2BP%255C-450%255C%2BEnzyme%255C%2BSystem%22
(1 - 20 of 49)