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Detection of salicylate and its hydroxylated adducts 2,3- and 2,5-dihydroxybenzoic acids as possible indices for in vivo hydroxyl radical formation in combination with catechol- and indoleamines and their metabolites in cerebrospinal fluid and brain tissue

Sloot, W.N. (author), Gramsbergen, J.B.P. (author), Instituut CIVO-Toxicologie en Voeding TNO (author)

It has been suggested that salicylate (SA) hydroxylation can be used to detect hydroxyl radical formation in vivo. Here we describe a rapid and sensitive HPLC method using ultraviolet absorbance (UV) and electrochemical detection (EC) to detect SA (UV), its hydroxylated adducts 2,3- and 2,5- dihydroxybenzoic acids (DHBA) and catechol in...

article 1995

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Cytotoxicity of retinoic acid, menadione and aflatoxin B1 in rat liver slices using netwell inserts as a culture system

Leeman, W.R. (author), van de Gevel, I.A. (author), Rutten, A.A.J.J.L. (author), Instituut CIVO-Toxicologie en Voeding TNO (author)

Precision-cut rat liver slices were used to develop a new dynamic incubation system in which histomorphology and measurement of the release of lactate dehydrogenase (LDH) and the conversion of MTT were applied to evaluate cytotoxicity. Liver slices, precision-cut using a Krumdieck tissue slicer, were cultured in a new system using 200-μm...

article 1995

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The thymus atrophy inducing organotin compound DBTC stimulates TCRalfabeta-CD3 signalling in immature rat thymocytes

Pieters, R.H.H. (author), Punt, P. (author), Bol, M. (author), van Dijken, J.M. (author), Seinen, W. (author), Penninks, A.H. (author), Instituut CIVO-Toxicologie en Voeding TNO (author)

In the present study, we show that the thymus atrophy inducing compound DBTC stimulates the intracellular release, but not the influx, of Ca2+ elicited by cross-linking of the TcRαβ-CD3-complex on rat thymocytes and inhibits capping of TcRαβ. Similarities with the effects of cytochalasin B together with the finding that DBTC also inhibited...

article 1995

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Normalized resistance and normalized flow to describe air way resistance

Zwart, A. (author), TNO Voeding Instituut CIVO-Toxicologie en Voeding TNO (author)

The effect of flow and flow patterns on the resistance of the airways was reinvestigated. A new way to describe pressure-flow relationships is introduced. Normalized resistance, Rn, is defined as resistance (P/φ) divided by the viscosity of the inspired gas (μ) relative to air (Rn = Rμ(u)/μ). Normalized flow φn is defined as flow times relative...

article 1994

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Wave propagation: A new parameter in the description of mechanical airway impedance

Zwart, A. (author), Arts, J.H.E. (author), Kuper, C.F. (author), Instituut CIVO-Toxicologie en Voeding TNO (author)

Time delay resulting from wave propagation in the elastic tubes of the respiratory system was entered as a parameter in the descriptive model of mechanical airway impedance. Characteristics of a three-parameter model with additional time delay (four parameters) were compared with those of the Dubois six-parameter model. Real and imaginary parts...

article 1994

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Prospective study on alcohol consumption and the risk of cancer of the colon and rectum in the Netherlands

Goldbohm, R.A. (author), van den Brandt, P.A. (author), van 't Veer, P. (author), Dorant, E. (author), Sturmans, F. (author), Hermus, R.J.J. (author), Instituut CIVO-Toxicologie en Voeding TNO (author)

The association between alcohol consumption and cancer of the colon and rectum was investigated in a prospective cohort study, conducted in the Netherlands from 1986 onwards among 120,852 men and women, aged 55 to 69 years. During 3.3 years of follow-up, 312 and 166 cases of colon and rectal cancer had accumulated, respectively. After exclusion...

article 1994

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Effects of moderate energy restriction on physical performance and substrate utilization in non-obese men

Velthuis-te Wierik, E.J.M. (author), Hoogzaad, L.V. (author), van den Berg, H. (author), Schaafsma, G. (author), Instituut CIVO-Toxicologie en Voeding TNO (author)

Energy restriction (ER) has shown to be an effective 'anti-aging' factor in rodents, resulting in an increased life span and preventing or delaying the occurrence of many age-related diseases in rodents. As a part of a feasibility study on the potential application of ER in humans, we studied the effects of moderate ER on physical performance in...

article 1994

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Involvement of human glutathione S-transferase isoenzymes in the conjugation of cyclophosphamide metabolites with glutathione

Dirven, H.A.A.M. (author), van Ommen, B. (author), van Bladeren, P.J. (author), Instituut CIVO-Toxicologie en Voeding TNO (author)

Alkylating agents can be detoxified by conjugation with glutathione (GSH). One of the physiological significances of this lies in the observation that cancer cells resistant to the cytotoxic effects of alkylating agents have higher levels of GSH and high glutathione S-transferase (GST) activity. However, little is known about the GSH-/GST...

article 1994

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Effects of clofibric and beclobric acid in rat and monkey hepatocyte primary culture: influence on peroxisomal and mitochondrial beta-oxidation and the activity of catalase, glutathione S-transferase and glutathione peroxidase

Instituut CIVO-Toxicologie en voeding TNO (author), Mennes, W.C. (author), Wortelboer, H.M. (author), Hassing, G.A. (author), van Sandwijk, K. (author), Timmerman, A. (author), Schmid, B.P. (author), Jahn, U. (author), Blaauboer, B.J. (author)

article 1994

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Health risk and risk management in the cultivation of chrysanthemums in greenhouses

Instituut CIVO-Toxicologie en Voeding TNO (author), Brouwer, D.H. (author), Geuskens, R.B.M. (author)

article 1994

document

Vitamin D

van den Berg, H. (author), Instituut CIVO-Toxicologie en Voeding TNO (author)

Chemicals/CAS: Vitamin D, 1406-16-2

article 1993

document

Expression and modulation of adhesion molecules on human bronchial epithelial cells

Bloemen, P.G.M. (author), van den Tweel, M.C. (author), Henricks, P.A.J. (author), Engels, F. (author), Wagenaar, S.S. (author), Rutten, A.A.J.J.L. (author), Nijkamp, F.P. (author), Instituut CIVO-Toxicologie en Voeding TNO (author)

article 1993

document

FLAIR concerted action no. 10 status papers: Introduction, conclusions and recommendations

van den Berg, H. (author), Heseker, H. (author), Lamand, M. (author), Sandström, B. (author), Thurnham, D. (author), Instituut CIVO-Toxicologie en Voeding TNO (author)

article 1993

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Differences in the effects of model inducers of cytochrome P450 on the biotransformation of scoparone in rat and hamster liver

Instituut CIVO-Toxicologie en voeding TNO (author), Mennes, W.C. (author), Wortelboer, H.M. (author), Hassing, G.A. (author), van Sandwijk, K. (author), Timmerman, A. (author), Schmid, B.P. (author), Jahn, U. (author), Blaauboer, B.J. (author)

The hamster is known to display very high rates of monooxygenase-mediated biotransformation. In comparison with other species little knowledge has been gathered with respect to the nature of its cytochrome P450 enzymes and their respective inducibility. We studied the consequences of induction of P450 enzymes in rats and Syrian golden hamsters...

article 1993

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Voeding en kankerpreventie: Handvatten voor de huisarts?

Bausch-Goldbohm, R.A. (author), Instituut CIVO-Toxicologie en Voeding TNO (author)

article 1993

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Cytochrome P450-mediated oxidation of pentafluorophenol to tetrafluorobenzoquinone as the primary reaction product

Instituut CIVO-Toxicologie en Voeding TNO (author), den Besten, C. (author), van Bladeren, P.J. (author), Duizer, E. (author), Vervoort, J. (author), Rietjens, I.M.C.M. (author)

In the present study the oxidative dehalogenation of a para-halogenated phenol was studied using pentafluorophenol and its non-para-halogenated analogue 2,3,5,6-tetrafluorophenol as model compounds. 19F NMR was used to characterize the metabolite patterns. In order to study the primary oxidation products of the microsomal cytochrome P450...

article 1993

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Biotransformation of 1,2 dihydronaphthalene and 1,2-dihydroanthracene by rat liver microsomes and purified cytochromes P-450. Formation of arene hydrates of naphthalene and anthracene

Instituut CIVO-Toxicologie en Voeding TNO (author), Boyd, D.R. (author), Sharma, N.D. (author), Agarwal, R. (author), McMordie, R.A.S. (author), Bessems, J.G.M. (author), van Ommen, B. (author), van Bladeren, P.J. (author)

Both 1,2-dihydronaphthalene and 1,2-dihydroanthracene were hydroxylated at the benzylic (1-) or the allylic (2-) position by rat liver microsomes and purified cytochrome P-450 enzymes to yield "arene hydrates". Two other classes of metabolites were formed, the dehydrogenation products naphthalene and anthracene, and trans-1,2-dihydroxy-1,2,3,4...

article 1993

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Risk assessment of dermal exposure of greenhouse workers to pesticides after re-entry

Brouwer, R. (author), Marquart, H. (author), de Mik, G. (author), van Hemmen, J.J. (author), Medisch Biologisch Laboratorium TNO Instituut CIVO-Toxicologie en Voeding TNO (author)

On 18 farms for rose culture in greenhouses in The Netherlands, dermal exposure of hands and forearms to abamectin (avermectin B1), dodemorph (4- cyclododecyl-2,6-dimethylmorpholinium acetate) and bupirimate (5-butyl-2- (ethylamino)-6-methyl-4-pyrimidinyl dimethylsulphate) was measured during crop activities. Dermal exposure during cutting (75...

article 1992

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Interlaboratory comparison of microsomal ethoxyresorufin and pentoxyresorufin O-dealkylation determinations: standardization of assay conditions

Instituut CIVO-Toxicologie en Voeding TNO (author), Rutten, A.A.J.J.L. (author), Falke, H.E. (author), Catsburg, J.F. (author), Wortelboer, H.M. (author), Blaauboer, B.J. (author), Doorn, L. (author), van Leeuwen, F.X.R. (author), Theelen, R. (author), Rietjens, I.M.C.M. (author)

Assay conditions and results of cytochrome P-450 dependent 7-ethoxyresorufin (ER) and 7-pentoxyresorufin (PR) O-dealkylation (OD) by rat liver microsomes were compared by four laboratories in the Netherlands. Microsomal mixtures were prepared from control, 3-methylcholanthrene and phenobarbital pretreated animals, resulting in different levels...

article 1992

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Purification and characterization of eight glutathione S-transferase isoenzymes of hamster: comparison of subunit composition of enzymes from liver, kidney, testis, pancreas and trachea

Instituut CIVO-Toxicologie en Voeding TNO (author), Bogaards, J.J.P. (author), van Ommen, B. (author), van Bladeren, P.J. (author)

Eight dimeric isoenzymes of glutathione S-transferase (GST) were purified from liver, kidney and testis of the Syrian golden hamster, using S-hexylglutathione affinity chromatography and chromatofocusing. The isoenzymes were characterized according to their substrate selectivity, physical properties and amino acid sequence analysis. Thus a...

article 1992