Activation of the liver carcinogen 2-nitropropane by aryl sulfotransferase.

abstract：:S-(1,2-Dichlorovinyl)-L-cysteine (DCVC), a mutagenic and nephrotoxic metabolite of trichloroethylene, is bioactivated to S-(1,2-dichlorovinyl)-L-cysteine sulfoxide (DCVCS) and chlorothioketene and/or 2-chlorothionoacetyl chloride by cysteine conjugate S-oxidase (S-oxidase) and cysteine conjugate beta-lyase (beta-lyase...

journal_title：Chemical research in toxicology

authors： Barshteyn N,Elfarra AA

更新日期：2009-09-01 00:00:00

abstract：:3-Alkyl-1,2,3-oxadiazolinium ions 1 have been proposed as reactive intermediates in the activation of (2-hydroxyethyl)nitrosamines. The reaction of 3-methyl-1,2,3-oxadiazolinium tosylate (1a), 2-ethyl-1-methoxy-2-phenyldiazenium tetrafluoroborate (3), and 3-phenyl-1,2,3-oxadiazolinium triflate (1b) with thiols was inv...

journal_title：Chemical research in toxicology

authors： Loeppky RN,Srinivasan A

更新日期：1995-09-01 00:00:00

abstract：:Furan has been found in a number of heated food items and is carcinogenic in the liver of rats and mice. Estimates of human exposure on the basis of concentrations measured in food are not reliable because of the volatility of furan. A biomarker approach is therefore indicated. We searched for metabolites excreted in ...

journal_title：Chemical research in toxicology

authors： Kellert M,Wagner S,Lutz U,Lutz WK

更新日期：2008-03-01 00:00:00

abstract：:N-Nitrosopyrrolidine (NPYR) is a well-established hepatocarcinogen in the rat. NPYR requires metabolic activation by cytochrome P450-catalyzed alpha-hydroxylation to express its carcinogenic activity. This produces alpha-hydroxyNPYR (2), which spontaneously ring opens to 4-oxobutanediazohydroxide (4), a highly reactiv...

journal_title：Chemical research in toxicology

authors： Wang M,Lao Y,Cheng G,Shi Y,Villalta PW,Hecht SS

更新日期：2007-04-01 00:00:00

abstract：:Prolonged exposure to estrogens correlates with an increased risk for breast cancer. One explanation is that estrogen metabolites cause mutations by reacting with DNA, leading to depurination. We describe an extraction procedure and a liquid chromatographic tandem mass spectrometric (LC/MS/MS) assay to detect estrone-...

journal_title：Chemical research in toxicology

authors： Zhang Q,Aft RL,Gross ML

更新日期：2008-08-01 00:00:00

abstract：:The ability of the carcinogenic mycotoxin ochratoxin A (OTA) to react with reduced glutathione (GSH) has been assessed using electrospray ionization (ES)-MS techniques. On the basis of the assumption that OTA undergoes biotransformation into the reactive quinone species OTQ (6), a synthetic sample of the reduced form ...

journal_title：Chemical research in toxicology

authors： Dai J,Park G,Wright MW,Adams M,Akman SA,Manderville RA

更新日期：2002-12-01 00:00:00

abstract：:Chromium(III) tris(picolinate) [Cr(pic)3] is currently a very popular nutritional supplement; however, its safety has recently been questioned, especially with regard to its ability to act as a clastogen. At physiologically relevant concentrations, Cr(pic)3 is reduced by biological reductants, including ascorbate and ...

journal_title：Chemical research in toxicology

authors： Speetjens JK,Collins RA,Vincent JB,Woski SA

更新日期：1999-06-01 00:00:00

abstract：:The mechanism of aromatic hydroxylation of estrogens by cytochrome P450 enzymes has been examined by comparing the oxidation of estrone with that of substrates carrying additional aromaticity such as equilenin and the structural analog 2-naphthol. Hamster liver microsomes preferentially catalyzed the conversion of est...

journal_title：Chemical research in toxicology

authors： Sarabia SF,Zhu BT,Kurosawa T,Tohma M,Liehr JG

更新日期：1997-07-01 00:00:00

abstract：:NADPH in microsomes reduces the hydroxocob(III)alamin form of vitamin B12 to cob(II)alamin and the supernucleophilic cob(I)alamin, which are both highly reactive toward xenobiotic epoxides formed by mammalian metabolism of dienes such as the industrially important chemicals chloroprene and 1,3-butadiene. With styrene,...

journal_title：Chemical research in toxicology

authors： Watson WP,Munter T,Golding BT

更新日期：2004-12-01 00:00:00

abstract：:Hemoglobin adducts have been used to assess exposure to carcinogenic compounds in tobacco smoke. However, because of background levels in nonsmokers, most adducts that have been studied are not useful for monitoring low-level exposure. Bergmark [(1997) Chem. Res. Toxicol. 10, 78-84] showed that the level of adducts of...

journal_title：Chemical research in toxicology

authors： Pérez HL,Segerbäck D,Osterman-Golkar S

更新日期：1999-10-01 00:00:00

abstract：:The effect of adduct stereochemistry on the susceptibility to hydrolysis by snake venom (VPD) and bovine spleen (SPD) phosphodiesterases was investigated with short deoxyoligonucleotides containing defined adducts derived from alkylation of the exocyclic 6-amino group of dA by polycyclic aromatic hydrocarbon diol epox...

journal_title：Chemical research in toxicology

authors： Ilankumaran P,Pannell LK,Gebreselassie P,Pilcher AS,Yagi H,Sayer JM,Jerina DM

更新日期：2001-09-01 00:00:00

abstract：:The mechanism of the hepatotoxicity of the analgesic acetaminophen is believed to be mediated by covalent binding to protein; however, critical targets which effect the toxicity are unknown. It has been shown that mitochondrial respiration in vivo is inhibited in mice as early as 1 h following a hepatotoxic dose of ac...

journal_title：Chemical research in toxicology

authors： Halmes NC,Hinson JA,Martin BM,Pumford NR

更新日期：1996-03-01 00:00:00

abstract：:Pesticide biotransformation, especially by cytochrome P450 enzymes (CYPs), may produce metabolites with substantially altered toxicological and physicochemical profiles, which has drawn great attention as a basis for environmental risk assessment. CYPs are active in the metabolism of various reactions of pesticides, a...

journal_title：Chemical research in toxicology

authors： Chai L,Ji S,Zhang S,Yu H,Zhao M,Ji L

更新日期：2020-06-15 00:00:00

abstract：:Thioureas are oxygenated by flavin-containing monooxygenases (FMOs), forming reactive sulfenic and/or sulfinic acids. Sulfenic acids can reversibly react with GSH and drive oxidative stress through a redox cycle. For this reason, thiourea S-oxygenation is an example of FMO-dependent bioactivation of a xenobiotic. Func...

journal_title：Chemical research in toxicology

authors： Henderson MC,Krueger SK,Stevens JF,Williams DE

更新日期：2004-05-01 00:00:00

abstract：:The kinetics and mechanisms of the hydrolysis of cysteine thiosulfinate ester (CyS(O)SCy ( x- ), x = 0-2) have been investigated by stopped-flow spectrophotometry between pH 6 and pH 14. The rate-limiting reaction of hydroxide is observed for pH < 13. More complicated kinetics are observed above pH 13, where the hydro...

journal_title：Chemical research in toxicology

authors： Nagy P,Ashby MT

更新日期：2007-09-01 00:00:00

abstract：:It is vital that methylated trivalent arsenicals [MA(III) and DMA(III)] are described and characterized unequivocally due to their high toxicity. Two different ways of generating the methylated trivalent arsenicals have been practiced-reduction of the methylated pentavalent arsenical either by the sodium-metabisulfite...

journal_title：Chemical research in toxicology

authors： Hansen HR,Raab A,Jaspars M,Milne BF,Feldmann J

更新日期：2004-08-01 00:00:00

abstract：:Toxicity data for 82 aliphatic chemicals with an alpha,beta-unsaturated substructure were compiled. Toxicity was assessed in the 2-day Tetrahymena pyriformis population growth impairment assay. Toxic potency [log(IGC50(-1))] for most of these chemicals was in excess of baseline narcosis as quantified by the 1-octanol/...

journal_title：Chemical research in toxicology

authors： Schultz TW,Netzeva TI,Roberts DW,Cronin MT

更新日期：2005-02-01 00:00:00

abstract：:DNA-DNA cross-linking by 1,2,3,4-diepoxybutane (DEB) is considered the molecular basis for its potent cytotoxic and genotoxic effects. DEB reactions with DNA initially lead to N7-(2'-hydroxy-3',4'-epoxybut-1'-yl)-guanine monoadducts, which can then alkylate neighboring DNA bases to form bifunctional lesions. We recent...

journal_title：Chemical research in toxicology

authors： Tretyakova N,Livshits A,Park S,Bisht B,Goggin M

更新日期：2007-02-01 00:00:00

abstract：:The Salmonella typhimurium (TA100) mutagenic compound, mucochloric acid [3,4-dichloro-5-hydroxy-2(5H)-furanone (MCA)], was inactivated by in vitro N-acetylcysteine (NAC). The reaction of MCA with NAC at pH7 was second order and gave products 4, 5, and 6a that resulted from the displacement of chlorine from C-3 or C-4 ...

journal_title：Chemical research in toxicology

authors： LaLonde RT,Xie S

更新日期：1992-09-01 00:00:00

abstract：:The measurement of metabolites constitutes a useful tool for detection of exposure and in pharmacokinetic studies. Epoxidation with subsequent glutathione conjugation and mercapturic acid formation is an important deactivation pathway for naphthalene, a toxin which presumably causes lung disease. The mercapturic acid ...

journal_title：Chemical research in toxicology

authors： Marco MP,Nasiri M,Kurth MJ,Hammock BD

更新日期：1993-05-01 00:00:00

abstract：:Estrogen replacement therapy has been correlated with an increased risk of developing breast or endometrial cancer. 4-Hydroxyequilenin (4-OHEN) is a catechol metabolite of equilenin which is a minor component of the estrogen replacement formulation marketed under the name of Premarin (Wyeth-Ayerst). Previously, we sho...

journal_title：Chemical research in toxicology

authors： Chen Y,Liu X,Pisha E,Constantinou AI,Hua Y,Shen L,van Breemen RB,Elguindi EC,Blond SY,Zhang F,Bolton JL

更新日期：2000-05-01 00:00:00

abstract：:beta-Carotene and other carotenoids are thought to exert disease preventive actions by scavenging reactive free radicals, but the mechanisms of these reactions are poorly understood. We detected products formed by reaction of beta-carotene with alkoxyl, and alkylperoxyl free radicals generated by thermolysis of azobis...

journal_title：Chemical research in toxicology

authors： Liebler DC,McClure TD

更新日期：1996-01-01 00:00:00

abstract：:The present study describes a novel integrated approach for rapid analysis of reactive metabolites with a linear ion trap mass spectrometer (LTQ). In this approach, an isotope pattern-dependent scanning method was applied to the data acquisition of glutathione (GSH)-trapped reactive metabolites. Recorded full-scan MS ...

journal_title：Chemical research in toxicology

authors： Ma L,Wen B,Ruan Q,Zhu M

更新日期：2008-07-01 00:00:00

abstract：:We investigated the effect of a series of Maillard reaction products formed from carbohydrates under household heating conditions on the growth of human tumor cells in vitro. 4-Hydroxy-5-methyl-3-(2H)-furanone (1) was found to potently enhance the proliferation of human tumor cells. In contrast, the Maillard-type chro...

journal_title：Chemical research in toxicology

authors： Marko D,Habermeyer M,Kemény M,Weyand U,Niederberger E,Frank O,Hofmann T

更新日期：2003-01-01 00:00:00

abstract：:All pesticides must go through a rigorous risk assessment process in order to show that they are safe for use.With respect to dermal risk assessment for re-entry workers, the absorption value applied to predict systemic dose from this external exposure is obtained by testing liquid forms of the pesticide in vivo and/o...

journal_title：Chemical research in toxicology

authors： Clarke JF,Cordery SF,Morgan NA,Knowles PK,Guy RH

更新日期：2015-02-16 00:00:00

abstract：:Previously, we reported a new animal model of an idiosyncratic drug reaction in which nevirapine causes a skin rash in some rats that has characteristics similar to the reaction that occurs in humans. Strong evidence that the reaction is immune-mediated was found; specifically, low-dose pretreatment induced tolerance,...

journal_title：Chemical research in toxicology

authors： Shenton JM,Popovic M,Chen J,Masson MJ,Uetrecht JP

更新日期：2005-12-01 00:00:00

abstract：:Previous studies suggested that lamotrigene (LTG) underwent bioactivation to a reactive aryl epoxide intermediate in rats. Nevertheless, definitive structures of these thioether conjugates, which are often needed to substantiate the mechanism of bioactivation and identity of reactive intermediate(s), were not fully es...

journal_title：Chemical research in toxicology

authors： Chen H,Grover S,Yu L,Walker G,Mutlib A

更新日期：2010-01-01 00:00:00

abstract：:Radionuclides represent a serious health risk to humans in the case of incorporation. To elucidate the potential of time-resolved laser-induced fluorescence spectroscopy (TRLFS) to determine the dominant radionuclide species in natural biofluids, we investigated the in vitro speciation of curium(III) in human urine sa...

journal_title：Chemical research in toxicology

authors： Heller A,Barkleit A,Bernhard G

更新日期：2011-02-18 00:00:00

abstract：:Methylmercury (MeHg) reacts readily with GSH, leading to the formation of a MeHg-SG adduct that is excreted into extracellular space through multidrug-resistance-associated protein (MRP), which is regulated by the transcription factor Nrf2. We previously reported that MeHg covalently modifies Keap1 and activates Nrf2 ...

journal_title：Chemical research in toxicology

authors： Yoshida E,Abiko Y,Kumagai Y

更新日期：2014-10-20 00:00:00

abstract：:Quinones represent a class of toxicological intermediates which can create a variety of hazardous effects in vivo, including acute cytotoxicity, immunotoxicity, and carcinogenesis. The mechanisms by which quinones cause these effects can be quite complex. Quinones are Michael acceptors, and cellular damage can occur t...

journal_title：Chemical research in toxicology

authors： Bolton JL,Trush MA,Penning TM,Dryhurst G,Monks TJ

更新日期：2000-03-01 00:00:00