- Monoclonal antibody-based ELISAs for part-per-billion determination of polycyclic aromatic hydrocarbons: Effects of haptens and formats on sensitivity and specificity
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As a first step toward developing sensitive enzyme-linked immunosorbent assays (ELISAs) for multianalyte detection of polycyclic aromatic hydrocarbons (PAHs), haptens with different lengths of carboxylic acid spacers at various positions were derived from naphthalene, fluorene, anthracene, phenanthrene, pyrene, fluoranthene, chrysene, and benzotalpyrene (BaP). These haptens were coupled with bovine serum albumin (BSA) to form competitor conjugates. All of these haptens were recognized to different extents by monoclonal antibodies (MAbs) 4D5 and 10C10 originally derived by Gomes and Santella (Chem. Res. Toxicol. 1990, 3, 307-310). The most sensitive indirect ELISAs were obtained by coating wells with the least competitive conjugates. Direct ELISAs using horseradish peroxidase conjugates of pyrene and BaP were less sensitive. The MAbs bound BaP with spacers at either C1 or C6. The cross-reactivity profiles of the eight PAHs were different with each PAH-BSA conjugate used as coating antigen. The ELISA results for BaP closely correlated with those by gas chromatography (GC), but the detection limit of the ELISA was ~150-fold more sensitive than that of GC, with 2-600 nM spike recoveries of 80-127% from human urine and canal and tap water.
- Li, Kai,Chen, Rongliang,Zhao, Bitao,Liu, Mei,Karu, Alexander E.,Roberts, Victoria A.,Li, Qing X.
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- Synthesis of phenol and quinone metabolites of benzo[a]pyrene, a carcinogenic component of tobacco smoke implicated in lung cancer
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Polycyclic aromatic hydrocarbons (PAHs) are widespread environmental pollutants produced in the combustion of organic matter. PAHs are present in automobile exhaust and tobacco smoke, and they have recently been designated as human carcinogens. Current ev
- Xu, Daiwang,Penning, Trevor M.,Blair, Ian A.,Harvey, Ronald G.
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p. 597 - 604
(2009/06/20)
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- Efficient syntheses of C8-aryl adducts of adenine and guanine formed by reaction of radical cation metabolites of carcinogenic polycyclic aromatic hydrocarbons with DNA
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(Chemical Equation Presented) The synthesis of the C8-aryl adducts of adenine and guanine formed by reaction of the radical cation metabolites of carcinogenic polycyclic aromatic hydrocarbons (PAHs), such as benzo[a]pyrene (BP) and dibenzo[def,p]chrysene (DBC), with DNA is reported. The synthetic approach involves in the key step direct reaction of a PAH aldehyde with a di- or triamine precursor of a purine. The method is operationally simple, affords good yields of adducts, and is broad in its scope. The C 8-aryl adducts of adenine and guanine derived from BP (6-BP-8-Ade and 6-BP-8-Gua) and DBC (10-DBC-8-Ade and 10-DBC-8-Gua) were synthesized in good yields by this method. Analogous C8-aryl adenine and guanine derivatives of other PAHs (anthracene, benz[a]anthracene, and chrysene) were also readily prepared via this approach. This method of synthesis is superior to the only method mat is currently available. It entails direct reaction of short-lived PAH radical cations (generated electrochemically or chemically) with 2′-deoxyribonucleosides or the corresponding purine bases. It provides the adducts in low yields accompanied by complex mixtures of secondary products. An alternative synthesis that involves Pd-catalyzed Suzuki-Miyaura coupling of arylboronic acids with 8-bromopurine nucleosides was also investigated. Although the C8-purine adducts of PAHs, such as naphthalene, phenanthrene, pyrene, and chrysene, could be prepared by this method, analogous adducts of carcinogenic PAHs and other structurally related PAHs, e.g., anthracene, benz[a]anthracene, benzo[a]pyrene, and dibenzo[def,p]chrysene, could not be obtained. This difference was shown to be a consequence of the facility of competing hydrolytic deboronation of the corresponding arylboronic acids.
- Dai, Qing,Xu, Daiwang,Lim, Keunpoong,Harvey, Ronald G.
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p. 4856 - 4863
(2008/02/05)
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- Synthesis and characterization of nucleosides and oligonucleotides with a benzo[a]pyren-6-ylmethyl adduct at adenine N6 or guanine N2
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Benzo[a]pyrene (1) can be converted to reactive electrophilic species by a number of metabolic pathways, of which the route to the mutagenic and carcinogenic diol epoxide(s) is the best studied. An alternative and interesting pathway to a highly genotoxic electrophile is through alkylation at the 6 position to 6-methylbenzo[a]pyrene (2) followed by oxidation of the methyl group to give 6-hydroxymethylbenzo[a]pyrene (3). Esterification of 3, especially to sulfate ester 4, gives compounds which are both mutagenic and carcinogenic. The major DNA adduct identified from exposure of rats and mice to 4 is the guanine N2 adduct [2′-deoxy-N2-(benzo-[a]pyren-6-ylmethyl)guanosine,5] which is also formed via activation of 2 to a radical cation species by horseradish peroxidase/H2O2 or iodine. To study the biological and structural properties of this adduct and the analogous adenine N6 adduct (6), a nonbiomimetic synthesis of the adducted nucleosides 5 and 6 has been developed and has been extended to preparation of oligonucleotides containing 5 or 6 at a single site.
- Kim,Cooper,Nechev,Harris,Harris
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p. 1306 - 1314
(2007/10/03)
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