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1,3-Butadiene (BD) is an important chemical used largely in the manufacture of synthetic rubber and thermoplastic resins. In addition, it has been identified in cigarette smoke, automobile exhaust, and gasoline vapor. The objective of this research was to develop highly sensitive and specific assays for the detection and quantitation of hemoglobin adducts(More)
Dose-response relationships of genotoxic agents differ greatly depending on the agent and the endpoint being evaluated. Simple conclusions that genotoxic effects are linear cannot be applied universally. The shape of the molecular dose of DNA adducts varies from linear, to supralinear, to sublinear depending on metabolic activation and detoxication, and(More)
The purposes of the present study were: (i) to investigate the potential use of several biomarkers as quantitative indicators of the in vivo conversion of ethylene (ET) to ethylene oxide (EO); (ii) to produce molecular dosimetry data that might improve assessment of human risk from exogenous ET exposures. Groups (n = 7/group) of male F344 rats and B6C3F1(More)
Propylene oxide (PO) is a relatively weak mutagen that induces nasal tumor formation in rats during long-term inhalation studies at high exposures (> or =300 p.p.m.), concentrations that also cause cytotoxicity and increases in cell proliferation. Direct alkylation of DNA by PO leads mainly to the formation of N:7-(2-hydroxypropyl)guanine (7-HPG). In this(More)
A gas chromatography/electron capture/negative chemical ionization high-resolution mass spectrometry (GC/EC/NCI-HRMS) method was developed for quantitating N7-(2-hydroxyethyl)guanine (N7-HEG) with excellent sensitivity and specificity. [4,5,6,8-(13)C(4)]-N7-HEG was synthesized, characterized, and quantitated using HPLC/electrospray ionization mass(More)
We have previously described an immunoaffinity/gas chromatography/electron capture negative chemical ionization high-resolution mass spectrometry (IA/GC/ECNCI-HRMS) assay for quantitation of the promutagenic DNA adduct N(2),3-ethenoguanine (N(2),3-epsilonGua) in vivo. Here we present an expanded assay that allows simultaneous quantitation of its structural(More)
Although vinyl chloride (VC) clearly induces hepatic angiosarcoma in humans and rodents, a causal association with brain tumors has not been definitively established with the available epidemiological and experimental evidence. Because VC acts by genotoxic mechanisms, DNA adduct formation is thought to be a sensitive biomarker of early events in(More)
The detection of hemoglobin adducts by mass spectrometry is a very sensitive and specific measurement of the extent of covalent binding of electrophilic chemicals. The exposure-dependent accumulation of N-(2-hydroxypropyl)valine (N-HPVal) in globin of rats exposed to propylene oxide (PO) (0, 5, 25, 50, 300 or 500 ppm) by the inhalation route was measured to(More)
Choline is important for normal membrane function, acetylcholine synthesis, lipid transport, and methyl metabolism. The U.S. National Academy of Sciences recently set requirements for choline in the human diet. In tissues and foods, there are multiple choline compounds that contribute to choline content. Betaine, a derivative of choline, is also important(More)
The analytical potential of gas chromatography/electron capture negative chemical ionization high-resolution mass spectrometry (HRMS) for characterization and quantitation of DNA and hemoglobin adducts was demonstrated using three model compounds: N2, 3-ethenoguanine (EG), 7-(2-hydroxyethyl)guanine (7-HEG), and N-(2-hydroxyethyl)valine (HEV). At a resolving(More)