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Sample records for aromatic hydrocarbon-dna adduct

  1. Polycyclic aromatic hydrocarbon-DNA adducts and the CYP1A1 restriction fragment length polymorphism

    SciTech Connect

    Shields, P.G.; Bowman, E.D.; Weston, A.; Harris, C.C.; Sugimura, H.; Caporaso, N.E.; Petruzzelli, S.F. ); Trump, B.F. )

    1992-11-01

    Human cancer risk assessment at a genetic level involves the investigation of carcinogen metabolism and DNA adduct formation. Wide interindividual differences in metabolism result in different DNA adduct levels. For this and other reasons, many laboratories have considered DNA adducts to be a measure of the biologically effective dose of a carcinogen. Techniques for studying DNA adducts using chemically specific assays are becoming available. A modification of the [sup 32]P-postlabeling assay for polycyclic aromatic hydrocarbon DNA adducts described here provides potential improvements in quantification. DNA adducts, however, reflect only recent exposure to carcinogens; in contrast, genetic testing for metabolic capacity indicates the extent to which carcinogens can be activated and exert genotoxic effects. Such studies may reflect both separate and integrated risk factors together with DNA adduct levels. A recently described restriction fragment length polymorphism for the CYP1A1, which codes for the cytochrome P450 enzyme primarily responsible for the metabolic activation of carcinogenic polycyclic aromatic hydrocarbons, has been found to be associated with lung cancer risk in a Japanese population. In a subset of individuals enrolled in a US lung cancer case-control study, no association with lung cancer was found. 17 refs., 3 figs.

  2. Polycyclic aromatic hydrocarbon-DNA adducts in Beluga whales from the Arctic

    SciTech Connect

    Mathieu, A.; Payne, J.F.; Fancey, L.L.

    1997-09-01

    The Arctic is still relatively pristine in nature, but it is also vulnerable to pollution because contaminants originating from midlatitudes are transported to the Arctic by atmospheric processes, ocean currents, and river. Recognition of this fact of Arctic vulnerability has resulted in a Declaration on the Protection of the Arctic Environment by eight Arctic countries. A manifest aim of this declaration is to develop an Arctic Monitoring and Assessment Program. We report here on the presence of measurable levels of polycyclic aromatic hydrocarbon-DNA adducts, including relatively high levels in Arctic beluga (Delphinapterus leucas). These results lend support to the value of developing biological assessment programs for Arctic wildlife. 15 refs., 1 tab.

  3. Polycyclic aromatic hydrocarbon-DNA adducts and survival among women with breast cancer

    SciTech Connect

    Sagiv, Sharon K. Gaudet, Mia M.; Eng, Sybil M.; Abrahamson, Page E.; Shantakumar, Sumitra; Teitelbaum, Susan L.; Bell, Paula; Thomas, Joyce A.; Neugut, Alfred I.; Santella, Regina M.; Gammon, Marilie D.

    2009-04-15

    Polycyclic aromatic hydrocarbons (PAH) are mammary carcinogens in animal studies, and a few epidemiologic studies have suggested a link between elevated levels of PAH-DNA adducts and breast cancer incidence. An association between PAH-DNA adducts and survival among breast cancer cases has not been previously reported. We conducted a survival analysis among women with newly diagnosed invasive breast cancer between 1996 and 1997, enrolled in the Long Island Breast Cancer Study Project. DNA was isolated from blood samples that were obtained from cases shortly after diagnosis and assayed for PAH-DNA adducts using ELISA. Among the 722 cases with PAH-DNA adduct measurements, 97 deaths (13.4%) from all causes and 54 deaths (7.5%) due to breast cancer were reported to National Death Index (NDI) by December 31, 2002. Using Cox proportional hazards models and controlling for age at diagnosis, we did not find evidence that all-cause mortality (hazard ratio (HR)=0.88; 95% confidence interval (CI): 0.57-1.37), or breast cancer mortality (HR=1.20; 95% CI: 0.63-2.28) was strongly associated with detectable PAH-DNA adduct levels compared with non-detectable adducts; additionally, no dose-response association was observed. Among a subgroup with treatment data (n=520), adducts were associated with over a two-fold higher mortality among those receiving radiation, but mortality for adducts was reduced among hormone therapy users. Results from this large population-based study do not provide strong support for an association between detectable PAH-DNA adducts and survival among women with breast cancer, except perhaps among those receiving radiation treatment.

  4. The role of polycyclic aromatic hydrocarbon-DNA adducts in inducing mutations in mouse skin

    PubMed Central

    Chakravarti, Dhrubajyoti; Venugopal, Divya; Mailander, Paula C.; Meza, Jane L.; Higginbotham, Sheila; Cavalieri, Ercole L.; Rogan, Eleanor G.

    2008-01-01

    Polycyclic aromatic hydrocarbons (PAH) form stable and depurinating DNA adducts in mouse skin to induce preneoplastic mutations. Some mutations transform cells, which then clonally expand to establish tumors. Strong clues about the mutagenic mechanism can be obtained if the PAH-DNA adducts can be correlated with both preneoplastic and tumor mutations. To this end, we studied mutagenesis in PAH-treated early preneoplastic skin (1 day after exposure) and in the induced papillomas in SENCAR mice. Papillomas were studied by PCR amplification of the H-ras gene and sequencing. For benzo[a]pyrene (BP), BP-7,8-dihydrodiol (BPDHD), 7,12-dimethylbenz[a]anthracene (DMBA) and dibenzo[a,l]pyrene (DB[a,l]P), the codon 13 (GGC to GTC) and codon 61 (CAA to CTA) mutations in papillomas corresponded to the relative levels of Gua and Ade-depurinating adducts, despite BP and BPDHD forming significant amounts of stable DNA adducts. Such a relationship was expected for DMBA and DB[a,l]P, as they formed primarily depurinating adducts. These results suggest that depurinating adducts play a major role in forming the tumorigenic mutations. To validate this correlation, preneoplastic skin mutations were studied by cloning H-ras PCR products and sequencing individual clones. DMBA- and DB[a,l]P-treated skin showed primarily A.T to G.C mutations, which correlated with the high ratio of the Ade/Gua-depurinating adducts. Incubation of skin DNA with T.G-DNA glycosylase eliminated most of these A.T to G.C mutations, indicating that they existed as G.T heteroduplexes, as would be expected if they were formed by errors in the repair of abasic sites generated by the depurinating adducts. BP and its metabolites induced mainly G.C to T.A mutations in preneoplastic skin. However, PCR over unrepaired anti-BPDE-N2dG adducts can generate similar mutations as artifacts of the study protocol, making it difficult to establish an adduct-mutation correlation for determining which BP-DNA adducts induce the early

  5. Quantification of phase I / II metabolizing enzyme gene expression and polycyclic aromatic hydrocarbon-DNA adduct levels in human prostate

    PubMed Central

    John, Kaarthik; Ragavan, Narasimhan; Pratt, M. Margaret; Singh, Paras B.; Al-Buheissi, Salah; Matanhelia, Shyam S.; Phillips, David H.; Poirier, Miriam C.; Martin, Francis L.

    2008-01-01

    BACKGROUND Studies of migrant populations suggest that dietary and/or environmental factors play a crucial role in the aetiology of prostatic adenocarcinoma (CaP). The human prostate consists of the peripheral zone (PZ), transition zone (TZ) and central zone (CZ); CaP occurs most often in the PZ. METHODS To investigate the notion that an underlying differential expression of phase I/II genes, and/or the presence of polycyclic aromatic hydrocarbon (PAH)-DNA adducts might explain the elevated PZ susceptibility, we examined prostate tissues (matched tissue sets consisting of PZ and TZ) from men undergoing radical retropubic prostatectomy for CaP (n=26) or cystoprostatectomy (n=1). Quantitative gene expression analysis was employed for cytochrome P450 (CYP) isoforms CYP1A1, CYP1B1 and CYP1A2, as well as N-acetyltransferase 1 and 2 (NAT1 and NAT2) and catechol-O-methyl transferase (COMT). RESULTS CYP1B1, NAT1 and COMT were expressed in all tissue sets; levels of CYP1B1 and NAT1 were consistently higher in the PZ compared to TZ. Immunohistochemistry confirmed the presence of CYP1B1 (nuclear-associated and primarily in basal epithelial cells) and NAT1. Tissue sections from 23 of these aforementioned 27 matched tissue sets were analyzed for PAH-DNA adduct levels using antiserum elicited against DNA modified with r7, t8-dihydroxy-t-9,10-oxy-7,8,9,10-tetrahydro-benzo[a]pyrene (BPDE). PAH-DNA adduct levels were highest in glandular epithelial cells, but a comparison of PZ and TZ showed no significant differences. CONCLUSION Although expression of activating and/or detoxifying enzymes may be higher in the PZ, PAH-DNA adduct levels appear to be similar in both zones. Therefore, factors other than PAH-DNA adducts may be responsible for promotion of tumour formation in the human prostate. PMID:19143007

  6. Human placental glutathione S-transferase activity and polycyclic aromatic hydrocarbon DNA adducts as biomarkers for environmental oxidative stress in placentas from pregnant women living in radioactivity- and chemically-polluted regions

    PubMed Central

    Obolenskaya, Maria Yu.; Teplyuk, Nadiya M.; Divi, Rao L.; Poirier, Miriam C.; Filimonova, Nataliya B.; Zadrozna, Monika; Pasanen, Markku J.

    2012-01-01

    This study was designed to analyze the effect of environmental oxidative stress on human placental monooxygenases, glutathione S-transferase (GST) activity and polycyclic aromatic hydrocarbon (PAH)–DNA adducts in human term placentas from radioactivity-contaminated and chemically-polluted areas of the Ukraine and Belarus, and to compare these biomarkers to the newborn’s general health status. Placental PAH–DNA adduct formation, GST activity, 7-ethoxycoumarin O-deethylase (ECOD) activity, and thiobarbituric reactive substances (TBARS), an index of lipid peroxidation, were measured in groups of women exposed to different levels of radioactivity and PAH pollution. The in vitro metabolism data, obtained from 143 human placental samples at term, were compared to indices of maternal and newborn health. The highest ECOD activity was recorded in placentas obtained from chemically-polluted areas and a radioactivity-contaminated area; the ECOD activity was 7-fold and 2-fold higher compared to the region considered to be “clean”. Newborns with the most compromised health status displayed the greatest down-regulation of GST activity (144–162 mU mg protein−1 vs. 258–395 mU mg protein−1), enhanced ECOD activity and the highest level of PAH–DNA adduct formation. The highest level of TBARS was observed in women exposed to the highest levels of radiation. The efficiency of placental detoxification negatively correlated with maternal age and the health status of the newborn. Environmental oxidative stress was related to an increase in anemia, threatened abortions, toxemia, fetal hypoxia, spontaneous abortions and fetal hypotrophy. Our data suggest that chemically- or radioactivity-induced oxidative stress enhance cytochrome P450-mediated enzymatic activities potentially resulting in increased formation of reactive metabolites. The activity of GSH-transferase is not enhanced. This imbalance in detoxification capacity can be measured as increased production of PAH

  7. Polycyclic aromatic hydrocarbon-DNA adducts in white blood cell DNA and 1-hydroxypyrene in the urine from aluminum workers: relation with job category and synergistic effect of smoking.

    PubMed

    van Schooten, F J; Jongeneelen, F J; Hillebrand, M J; van Leeuwen, F E; de Looff, A J; Dijkmans, A P; van Rooij, J G; den Engelse, L; Kriek, E

    1995-01-01

    We examined a group of 105 workers from a primary aluminum plant for the presence of polycyclic aromatic hydrocarbon (PAH)-DNA adducts in their WBC and 1-hydroxypyrene in their urine. Workers were recruited from five job categories with different PAH exposure: the anode factory; the bake oven; and the electrolysis and the pot-relining departments. Unexposed workers from the foundry department served as the control group. The exposure to PAH was measured by personal monitoring, and the average PAH concentrations in the work atmosphere ranged from 0.4 micrograms/m3 in the foundry to 150 micrograms/m3 in the pot-relining department. The average exposure to benzo(a)pyrene was under the Swedish exposure limit of 5 micrograms/m3. The internal dose of pyrene was measured utilizing the 1-hydroxypyrene concentration in pre- and postshift urine samples. Higher exposure to PAH in the work atmosphere was associated with increased concentrations of 1-hydroxypyrene in the urine. The average increase in concentration of 1-hydroxypyrene ranged from 0.2 mumol/mol creatinine in the control group to 5.9 mumol/mol creatinine in the pot-relining department; an accumulation of 1-hydroxypyrene over a 5-day working period was observed. A good correlation was found between PAH exposure and the concentration of 1-hydroxypyrene in the urine on a group level (rs = 0.90; P = 0.02). PAH-DNA adducts were determined by 32P-postlabeling analysis (nuclease P1 enrichment procedure).(ABSTRACT TRUNCATED AT 250 WORDS)

  8. Haemoglobin adducts of aromatic amines: diamines and polyaromatic amines.

    PubMed

    Sabbioni, G; Beyerbach, A

    2000-07-21

    Aromatic amines and nitroarenes are important antioxidants and intermediates in the synthesis of dyes, pesticides and plastics. In the present paper we introduce methods for the synthesis of deuterated standards: 3-[2H8]aminofluoranthene, 3,3'-dimethyl-[2H4]benzidine, [2H4]benzidine, N'-acetyl-[2H4]benzidine, 2,4-[2H6]toluenediamine, 2,6-[2H6]toluenediamine. These standards have been used for the quantification of haemoglobin adducts of diamines and polyaromatic amines. Haemoglobin was hydrolysed in 0.1 M sodium hydroxide and the hydrolysate extracted with dichloromethane. The extracts were derivatised with heptafluorobutyric anhydride and analysed by GC-MS with negative chemical ionisation. In one run up to 15 aromatic amines can be determined: 6-aminochrysene, 3-aminofluoranthene, 2-aminofluorene, 1-aminopyrene, benzidine, 3,3'-dichlorobenzidine, 3,3'-dimethoxybenzidine, 3,3'-dimethylbenzidine, 3,3'-methylenedianiline, 4,4'-methylenedianiline, N'-acetyl-benzidine, N'-acetyl-4,4'-methylenedianiline, 4,4'-methylene bis(2-chloroaniline), 2,4-toluenediamine and 2,6-toluenediamine.

  9. NMR solution structures of adducts derived from the binding of polycyclic aromatic diol epoxides to DNA

    SciTech Connect

    Cosman, M.; Patel, D.J.; Hingerty, B.E.; Amin, S.; Broyde, S.; Geacintov, N.E.

    1995-12-31

    Site-specifically modified oligonucleotides were derived from the reactions of stereoisomeric polycyclic aromatic diol epoxide metabolite model compounds with oligonucleotides of defined base composition and sequence. The NMR solution structures of ten different adducts studied so far are briefly described, and it is shown that stereochemical factors and the nature of the oligonucleotide context of the complementary strands, exert a powerful influence on the conformational features of these adducts.

  10. Relating aromatic hydrocarbon-induced DNA adducts and c-H-ras mutations in mouse skin papillomas: the role of apurinic sites.

    PubMed Central

    Chakravarti, D; Pelling, J C; Cavalieri, E L; Rogan, E G

    1995-01-01

    Mouse skin tumors contain activated c-H-ras oncogenes, often caused by point mutations at codons 12 and 13 in exon 1 and codons 59 and 61 in exon 2. Mutagenesis by the noncoding apurinic sites can produce G-->T and A-->T transversions by DNA misreplication with more frequent insertion of deoxyadenosine opposite the apurinic site. Papillomas were induced in mouse skin by several aromatic hydrocarbons, and mutations in the c-H-ras gene were determined to elucidate the relationship among DNA adducts, apurinic sites, and ras oncogene mutations. Dibenzo[a,l]pyrene (DB[a,l]P), DB[a,l]P-11,12-dihydrodiol, anti-DB[a,l]P-11,12-diol-13,14-epoxide, DB[a,l]P-8,9-dihydrodiol, 7,12-dimethylbenz[a]anthracene (DMBA), and 1,2,3,4-tetrahydro-DMBA consistently induced a CAA-->CTA mutation in codon 61 of the c-H-ras oncogene. Benzo[a]pyrene induced a GGC-->GTC mutation in codon 13 in 54% of tumors and a CAA-->CTA mutation in codon 61 in 15%. The pattern of mutations induced by each hydrocarbon correlated with its profile of DNA adducts. For example, both DB[a,l]P and DMBA primarily form DNA adducts at the N-3 and/or N-7 of deoxyadenosine that are lost from the DNA by depurination, generating apurinic sites. Thus, these results support the hypothesis that misreplication of unrepaired apurinic sites generated by loss of hydrocarbon-DNA adducts is responsible for transforming mutations leading to papillomas in mouse skin. PMID:7479797

  11. CYCLOPENTA-FUSED POLYCYCLIC AROMATIC HYDROCARBONS IN STRAIN A/J MOUSE LUNG: DNA ADDUCTS, ONCOGENE MUTATIONS, & TUMORIGENESIS

    EPA Science Inventory

    Cyclopenta-fused Polycyclic Aromatic Hydrocarbons in Strain AJJ Mouse Lung: DNA Adducts, Oncogene Mutations, and Tumorigenesis.

    We have examined the relationships between DNA adducts, Ki-ras oncogene mutations, DNA adducts, and adenoma induction in the lungs of strain A/J...

  12. CYCLOPENTA-FUSED POLYCYCLIC AROMATIC HYDROCARBONS IN STRAIN A/J MOUSE LUNG: DNA ADDUCTS, ONCOGENE MUTATIONS, & TUMORIGENESIS

    EPA Science Inventory

    Cyclopenta-fused Polycyclic Aromatic Hydrocarbons in Strain AJJ Mouse Lung: DNA Adducts, Oncogene Mutations, and Tumorigenesis.

    We have examined the relationships between DNA adducts, Ki-ras oncogene mutations, DNA adducts, and adenoma induction in the lungs of strain A/J...

  13. Morinda citrifolia (noni) reduces cancer risk in current smokers by decreasing aromatic DNA adducts.

    PubMed

    Wang, Mian-Ying; Peng, Lin; Lutfiyya, May Nawal; Henley, Eric; Weidenbacher-Hoper, Vicki; Anderson, Gary

    2009-01-01

    Quantitative determination of aromatic DNA adducts in peripheral blood lymphocytes (PBLs) of current smokers is an useful surrogate biomarker for the evaluation of environmental carcinogen exposure or chemopreventive intervention. In this study, we examined the impact of Tahitian Noni Juice (TNJ) on the aromatic DNA adducts of PBLs, before and after a 1-mo intervention, using (32)P postlabeling assay. Of 283 enrolled, 203 smokers completed the trial. Aromatic DNA adducts levels in all participants were significantly reduced by 44.9% (P < 0.001) after drinking 1 to 4 oz of TNJ for 1 mo. Dose-dependent analyses of aromatic DNA adduct levels showed reductions of 49.7% (P < 0.001) in the 1-oz TNJ group and 37.6% (P < 0.001) in the 4-oz TNJ group. Gender-specific analyses resulted in no significant differences in the 4-oz TNJ groups. Interestingly, the 1-oz TNJ group showed a reduction of 43.1% (P < 0.001) in females compared with 56.1% (P < 0.001) in males. The results suggest that drinking 1 to 4 oz of TNJ daily may reduce the cancer risk in heavy cigarette smokers by blocking carcinogen-DNA binding or excising DNA adducts from genomic DNA.

  14. Serological characterization of polycyclic aromatic hydrocarbon diolepoxide-DNA adducts using monoclonal antibodies.

    PubMed

    Newman, M J; Weston, A; Carver, D C; Mann, D L; Harris, C C

    1990-11-01

    Polycyclic aromatic hydrocarbons (PAHs) are a group of structurally related compounds that are present in the environment in complex mixtures as common pollutants. These compounds have been studied extensively because of their carcinogenic and toxic properties to humans. We reported previously that humans exposed to certain PAHs produce antibodies that bind to different PAH diolepoxide-DNA (PAH-DNA) adducts. The ability to detect and measure antibodies to PAH-DNA adducts in human blood samples could prove useful as a biological dosimeter for identifying persons that have been exposed to high levels of PAHs, i.e. persons who may be at high cancer risk. In our initial studies we found that it was common for persons who were exposed to PAH to produce antibodies against PAH-DNA adducts. However, we were unable to identify the actual chemical types of PAH-DNA adducts that were recognized by the serum antibodies because many serum samples contained antibody activity to more than one adduct. These data indicate that different PAH-DNA adducts may be serologically similar or that humans actually produce immune responses against more than a single PAH-DNA adduct. We have used monoclonal antibody technology to determine the extent to which different PAH-DNA adducts share serologically recognized epitopes. Monoclonal antibodies were produced against two different PAH-DNA adducts, benzo[a]pyrene diolepoxide-DNA (BPDE-DNA) and benz[a]anthracene diolepoxide-DNA (BADE-DNA). The binding of these antibodies to five PAH-DNA adduct preparations and to soluble PAHs was assessed. We found that most monoclonal antibodies bound to more than a single type of PAH-DNA adduct, documenting the serological relatedness of different PAH-DNA adducts. However, two monoclonal antibodies were produced that bound only to BPDE-DNA. Soluble non-metabolized PAHs and PAH tetraols were not recognized by these antibodies, thus demonstrating their specificity for PAH-DNA adducts and not the PAHs alone

  15. Physico-chemical methods for the study of polycyclic aromatic hydrocarbon - DNA interactions. Progress report, October 1, 1985-September 30, 1986

    SciTech Connect

    Geacintov, N.E.

    1986-10-10

    Previous linear dichroism measurements suggested that the (-)BPDE-DNA adducts are characterized by considerable interactions between the pyrene residue and the DNA bases. Such a conformation is consistent with intercalation, or partial intercalation. With the pyrene residue thus protected from the solvent environment, one might expect a low degree of accessibility to acrylamide quencher molecules. Since the fluorescence of these (-)BPDE-DNA adducts is indeed insensitive to acrylamide, the quenching results reported here are consistent with such a conformation. The covalent adducts derived from the binding of (+)BPDE to DNA appear to be 70% accessible to acrylamide, suggesting that a majority of these adducts reside at external binding sites, or in a locally disordered region of the DNA double helix. Again, these conclusions derived from the fluorescence quenching data are consistent with our previous linear dichroism results. 3 refs., 3 figs.

  16. Conformations of DNA adducts with polycyclic aromatic carcinogens

    SciTech Connect

    Broyde, S.; Hingerty, B.

    1984-01-01

    Minimized semi-empirical potential energy calculations for a number of carcinogen adducts with dCpdG have yielded molecular views of the adduct conformations. The base displaced and Z type conformations of acetylaminofluorene (AAF) adducts to guanine C-8 have been detailed. Model building shows that base displacement causes kinking and denaturation in the B helix, while the Z helix is largely unperturbed by modification with AAF, in agreement with experimental findings. The minor AAF adduct linked to quanine N/sup 2/ can reside at a B-Z junction, with the carcinogen buried in a groove in the Z direction, without causing denaturation. The syn guanine in these modified Z forms could be mutagenic, the lesion escaping repair because the helix is undeformed, while the distorted base-displaced conformers are repaired. Aminofluorene (AF) and 4-aminobiphenyl (ABP) linked to guanine N/sup 2/ are currently believed to be critical lesions. They all have a pair of A or B type low energy states, one of which has base-base stacking with carcinogen at the helix exterior, and a second with carcinogen-base stacking. The two states are easily interconvertible. It is possible that the carcinogen may reside primarily at the unperturbed helix exterior where it escapes repair, but that carcinogen-base stacking may occur at a critical time during replication, leading to a mutation. 49 references, 8 figures.

  17. DNA adducts as a measure of lung cancer risk in humans exposed to polycyclic aromatic hydrocarbons.

    PubMed Central

    Kriek, E; Van Schooten, F J; Hillebrand, M J; Van Leeuwen, F E; Den Engelse, L; De Looff, A J; Dijkmans, A P

    1993-01-01

    Workers in the coking, foundry, and aluminum industry can be exposed to high concentrations of polycyclic aromatic hydrocarbons (PAHs) and are at increased risk for lung cancer, as are cigarette smokers. In recent years several studies on workers in the foundry and coking industries have been reported. In these studies, white blood cell(WBC) DNA was used for analysis of PAH-DNA adducts. Theoretically, DNA adduct formation is a more relevant biological parameter for assessing exposure risk than PAH in the work atmosphere, or the amount of a metabolite in the urine, because adduct levels reflect that part of the dose that escapes detoxification and binds to DNA. We analyzed WBC DNA from coke-oven workers and from workers in an aluminum production plant and demonstrated the presence of PAH-DNA adducts. Forty-seven percent of the coke-oven workers had detectable levels of PAH-DNA adducts in their WBC compared with 27% of the controls (p < 0.05), measured with ELISA. In both groups, smokers had significantly higher levels of PAH-DNA adducts than did nonsmokers. In the aluminum workers, no PAH-DNA adducts were detected by ELISA, although the benzo[a]pyrene concentrations in the work atmosphere were comparable to those of the coke-oven workers. The more sensitive 32P-postlabeling assay showed the presence of PAH-DNA adducts in 91% of the aluminum workers. There was no correlation of WBC adduct levels with the concentration of PAH in the work atmosphere. Recently we showed that total PAH-DNA adduct levels in WBC from lung cancer patients were much higher than those generally found in healthy smokers.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8319662

  18. Recoveries of DNA adducts of polycyclic aromatic hydrocarbons in the 32P-postlabelling assay.

    PubMed

    Segerbäck, D; Vodicka, P

    1993-12-01

    The 32P-postlabelling assay for analysis of DNA adducts of chemical carcinogens has been applied in a large number of experimental animal and human studies. Most human studies have dealt with occupational and environmental exposures to polycyclic aromatic hydrocarbons (PAHs). The postlabelling assay does not allow direct chemical identification, and most studies with this method have not been performed in a quantitative way. Very little is therefore known about the identity and absolute levels of adducts, which are important contributors to the process of risk identification and quantitation. In the present study it was, therefore, decided to test some parameters suspected to affect recoveries of adducts in the phosphorylation step of the assay. For this purpose 12 different PAHs were reacted individually and in a mixture with DNA in the presence of a rat liver S9 metabolizing system. Different concentrations of ATP, calcium chloride and polynucleotide kinase were tested using the nuclease P1 enhancement. We found that each factor contributed to adduct recovery and that optimal conditions could be defined. Diluting the modified DNA samples up to 1000 times had little influence on the recoveries of adducts. Comparing the nuclease P1 and the butanol extraction procedures for adduct purification showed that both methods gave similar patterns and levels of major adducts. The absolute recoveries in postlabelling, based on 3H-binding of radiolabelled compounds, were for most of the tested compounds relatively low. The fact that the nuclease P1 and the butanol extraction procedures gave similar recoveries points towards common factor(s) involved in the reduction of the recovered adduct levels. Based on the observed recoveries the conclusion can be drawn that when postlabelling related adducts in human samples the true total adduct levels can be considerably underestimated, even if optimal conditions are used.

  19. Detection and characterization of human serum antibodies to polycyclic aromatic hydrocarbon diol-epoxide DNA adducts.

    PubMed Central

    Newman, M J; Light, B A; Weston, A; Tollurud, D; Clark, J L; Mann, D L; Blackmon, J P; Harris, C C

    1988-01-01

    The presence of serum antibodies to the diol-epoxide DNA adducts of representative polycyclic aromatic hydrocarbons (PAH), chrysene, benz[a]anthracene and benzo[a]pyrene, was determined by ELISA using serum samples obtained from normal healthy individuals. Antibodies that reacted against PAH adducted-DNA, but not against PAH-adducted protein, were found in the serum of approximately 40% of the test individuals. Specificity analysis of the antibodies demonstrated that serological cross-reactions between the benzo[a]pyrene and the chrysene diol-epoxide adducts were present. Similar cross-reactivity between the benz[a]anthracene and the chrysene adducts was observed. Sera containing antibodies that were apparently specific for each of the three PAH-DNA adducts were also identified. The presence of antibodies to PAH-DNA adducts indicates both past exposure to these carcinogenic PAH and their metabolic activation to the DNA damaging metabolites. These antibodies may prove to be useful in both retrospective and prospective epidemiological studies of various diseases associated with PAH exposure. PMID:3392204

  20. DNA Adduct Formation of 4-Aminobiphenyl and Heterocyclic Aromatic Amines in Human Hepatocytes

    PubMed Central

    Nauwelaers, Gwendoline; Bessette, Erin E.; Gu, Dan; Tang, Yijin; Rageul, Julie; Fessard, Valérie; Yuan, Jian-Min; Yu, Mimi C.; Langouët, Sophie; Turesky, Robert J.

    2011-01-01

    DNA adduct formation of the aromatic amine, 4-aminobiphenyl (4-ABP), a known human carcinogen present in tobacco smoke, and the heterocyclic aromatic amines (HAAs), 2-amino-9H-pyrido[2,3-b]indole (AαC), 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), and 2-amino-3,8-dimethylmidazo[4,5-f]quinoxaline (MeIQx), potential human carcinogens, which are also present in tobacco smoke or formed during the high-temperature cooking of meats, was investigated in freshly cultured human hepatocytes. The carcinogens (10 μM) were incubated with hepatocytes derived from eight different donors for time periods up to 24 h. The DNA adducts were quantified by liquid chromatography-electrospray ionization mass spectrometry with a linear quadrupole ion trap mass spectrometer. The principal DNA adducts formed for all of the carcinogens were N-(deoxyguanosin-8-yl) (dG-C8) adducts. The levels of adducts ranged from 3.4 to 140 adducts per 107 DNA bases. The highest level of adduct formation occurred with AαC, followed by 4-ABP, then by PhIP, MeIQx, and IQ. Human hepatocytes formed dG-C8-HAA-adducts at levels that were up to 100-fold greater than the amounts of adducts produced in rat hepatocytes. In contrast to HAA adducts, the levels of dG-C8-4-ABP adduct formation were similar in human and rat hepatocytes. These DNA binding data demonstrate that the rat, an animal model that is used for carcinogenesis bioassays, significantly underestimates the potential hepatic genotoxicity of HAAs in humans. The high level of DNA adducts formed by AαC, a carcinogen produced in tobacco smoke at levels that are up to 100-fold higher than the amounts of 4-ABP, is noteworthy. The possible causal role of AαC in tobacco-associated cancers warrants investigation. PMID:21456541

  1. 32P-postlabeling analysis of non-radioactive aromatic carcinogen--DNA adducts.

    PubMed

    Gupta, R C; Reddy, M V; Randerath, K

    1982-01-01

    A newly developed enzymatic 32P-postlabeling method was applied to the analysis of DNA's containing non-radioactive arylamine, arylamide, and polycyclic aromatic hydrocarbon adducts. DNA reacted in vitro with N-hydroxy-2-amino-fluorene, N-acetoxy-2-acetylaminofluorene, and 7 beta,8 alpha-dihydroxy-9 alpha,10 alpha-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene, respectively, as well as DNA preparations from the liver of rats treated with N-hydroxy-2-acetylaminofluorene and benzo[a]pyrene, respectively, were enzymatically digested to deoxyribonucleoside 3'-monophosphates, which were then converted to [5'-32P]deoxyribonucleoside 3',5'-bisphosphates by T4 polynucleotide kinase-catalyzed [32P]phosphate transfer from [gamma-32P]ATP. The 32P-labeled nucleotides were resolved by anion-exchange t.l.c. on polyethyleneimine-cellulose and detected by autoradiography. Aromatic adduct nucleotides were found to be retained at the origin in aqueous electrolyte solutions, but to migrate as distinct spots in solvents containing 7-8.5 M urea. Advantage was taken of this observation to remove 32P-labeled normal DNA nucleotides from adduct nucleotides. This purification enabled the detection of a single adduct in 10(7)-10(8) normal nucleotides. The method appears applicable to the ultrasensitive detection of a large number of carcinogen--DNA adducts of diverse structure without requiring radioactive carcinogens or specific antibodies.

  2. DNA adducts as a measure of lung cancer risk in humans exposed to polycyclic aromatic hydrocarbons

    SciTech Connect

    Kriek, E.; Van Schooten, F.J.; Hillebrand, M.J.X.; Van Leeuwen, F.E.; Den Engelse, L.; De Looff, A.J.A.; Dijkmans, A.P.G.

    1993-03-01

    Workers in the coking, foundry, and aluminum industry can be exposed to high concentrations of polycyclic aromatic hydrocarbons (PAHs) and are at increased risk for lung cancer, as are cigarette smokers. In recent years several studies on workers in the foundry and coking industries have been reported. In these studies, white blood cell (WBC) DNA was used for analysis of PAH-DNA adducts. Theoretically, DNA adduct formation is a more relevant biological parameter for assessing exposure risk than PAH in the work atmosphere, or the amount of a metabolite in the urine, because adduct levels reflect that part of the dose that escapes detoxification and binds to DNA. WBC DNA was analyzed from coke-oven workers and from workers in an aluminum production plant and demonstrated the presence of PAH-DNA adducts. Forty-seven percent of the coke-oven workers had detectable levels of PAH-DNA adducts in their WBC compared with 27% of the controls (p < 0.05), measured with ELISA. In both groups, smokers had significantly higher levels of PAH-DNA adducts than did nonsmokers. In the aluminum workers, no PAH-DNA adducts were detected by ELISA, although the benzo[a]pyrene concentrations in the work atmosphere were comparable to those of the coke-oven workers. The more sensitive [sup 32]P-postlabeling assay showed the presence of PAH-DNA adducts in 91% of the aluminum workers. There was no correlation of WBC adduct levels with the concentration of PAH in the work atmosphere. Recently the authors showed that total PAH-DNA adduct levels in WBC from lung cancer patients were much higher than those generally found in healthy smokers. These increased adduct levels may indicate a subpopulation of smokers with increased risk for lung cancer, resulting from a genetic predisposition in this group of persons. Because WBCs are not the target cells for exposure-related cancer, the relationship between PAH-DNA adducts in the lung and in WBCs remains to be established. 30 refs., 2 figs., 2 tabs.

  3. Molecular mechanics and antibody binding in the structural analysis of polycyclic aromatic hydrocarbon-diol-epoxide--DNA adducts.

    PubMed

    Weston, A; Newman, M J; Mann, D L; Brooks, B R

    1990-05-01

    Analysis of polycyclic aromatic hydrocarbon (PAH)-DNA adducts using monoclonal antibodies raised against DNA that had been modified with (+-)-r-7-,t-8-dihydroxy-t-9,10-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene in an enzyme-linked immunosorbent assay, as well as analysis using human serum antibodies and antibodies raised in laboratory animals, have suggested the presence on these adducts of both common and unique immunological epitopes. The molecular mechanics studies reported here establish a model for the analysis of PAH-DNA adducts through the identification of energetically favored binding conformations and they further reveal structural alterations in DNA due to the presence of carcinogen adducts. The data explain the antibody reactivity patterns by defining different molecular presenting surfaces that are available for antibody binding. The preferred orientation of the aromatic portions of the adducts, which align either 3' or 5' in the minor groove, were found to be correlated with antibody reactivity patterns. Examination of the topographical characteristics of the adducts facilitated correlation of adduct-antibody recognition and adduct presenting surface. Significant differences were found between benzo[a]pyrene-diol-epoxide (BPDE)-DNA adducts, which align 5' in the minor groove, and benz[a]anthracene-diol-epoxide (BADE)-DNA and dibenz[a,c]anthracene-diol-epoxide-DNA adducts, which align 3' within the minor groove. Chrysene-diol-epoxide-DNA adducts were found to have only a weak preference for 5' alignment and therefore share topographical characteristics with both BPDE-DNA and BADE-DNA adducts.

  4. Benzo(a)pyrene-albumin adducts in humans exposed to polycyclic aromatic hydrocarbons in an industrial area of Poland.

    PubMed Central

    Kure, E H; Andreassen, A; Ovrebø, S; Grzybowska, E; Fiala, Z; Strózyk, M; Chorazy, M; Haugen, A

    1997-01-01

    OBJECTIVES: The interaction of benzo(a)pyrene with serum albumin was measured in an attempt to identify the actual exposure and to evaluate albumin adduct measurements as biomarkers for exposure monitoring. METHODS: Benzo(a)pyrene-diol-epoxide (BPDE)-albumin adducts were measured by competitive enzyme linked immunosorbent assay (ELISA) in plasma of coke oven plant workers from three plants and from people living in a highly industrialised area of Silesia in Poland. Due to the high air concentrations of polycyclic aromatic hydrocarbons (PAHs) in this area, a control group was selected from a rural non-industrialised area in Poland. Breathing zone air measurements of PAHs were collected from some of the participants. RESULTS: Coke oven plant workers and non-occupationally exposed people had similar concentrations of albumin adducts whereas the rural controls were significantly lower (2.74 fmol adducts/microgram albumin (SEM 0.124)). The mean concentration of BPDE-albumin adduct in plasma of both the occupational and the environmental groups were significantly higher in the summer samples (4.34 fmol adducts/microgram albumin (SEM 0.335) and 4.55 fmol adducts/microgram albumin (SEM 0.296), respectively) than in the winter samples (3.06 fmol adducts/microgram albumin (SEM 0.187) and 3.04 fmol adducts/microgram albumin (SEM 0.184), respectively) even though the air measurements showed higher concentrations of PAHs in the winter. The statistical analysis did not show any effects of air exposures on concentrations of BPDE-albumin adduct. CONCLUSIONS: A multiple regression analysis of the measured concentrations of BPDE-albumin adducts for all the groups, during both seasons, indicates that occupational exposures do not contribute significantly to the formation of adducts. In general, the concentrations of albumin adducts found vary within relatively small limits for the two seasons and between the various groups of participants. No extreme differences were found. PMID

  5. Aromatic DNA adducts and polymorphisms in metabolic genes in healthy adults: findings from the EPIC-Spain cohort.

    PubMed

    Agudo, Antonio; Peluso, Marco; Sala, Núria; Capellá, Gabriel; Munnia, Armelle; Piro, Sara; Marín, Fátima; Ibáñez, Raquel; Amiano, Pilar; Tormo, M José; Ardanaz, Eva; Barricarte, Aurelio; Chirlaque, M Dolores; Dorronsoro, Miren; Larrañaga, Nerea; Martínez, Carmen; Navarro, Carmen; Quirós, J Ramón; Sánchez, M José; González, Carlos A

    2009-06-01

    Aromatic compounds such as polycyclic aromatic hydrocarbons, arylamines and heterocyclic amines require metabolic activation to form metabolites able to bind to DNA, a process mediated by polymorphic enzymes. We measured aromatic DNA adducts in white blood cells by the (32)P-post-labelling assay in a sample of 296 healthy adults (147 men and 149 women) from five regions of Spain. We also analyzed functional polymorphisms in the metabolic genes CYP1A1, CYP1A2, EPHX1, GSTM1, GSTT1, NAT2 and SULT1A1. A significant increased level of DNA aromatic adducts was found related to the fast oxidation-hydrolysis phenotype defined by the polymorphism I462V in CYP1A1, the allele A in IVS1-154C>A of CYP1A2 and the combination Tyrosine-Arginine for Y113H and H139R of EPHX1. Geometric means (adducts per 10(-9) normal nucleotides) were 2.17, 4.04 and 6.30 for slow, normal and fast phenotypes, respectively (P-trend = 0.01). Slow acetylation by NAT2 was associated with a significant decrease in adduct level; subjects with slow alleles *5A and *7A/B had in average 1.56 x 10(-9)adducts, as compared with 5.60 for those with normal NAT2 activity (P-value = 0.01). No association was seen with polymorphisms of other metabolic genes such as GSTM1, GSTT1 or SULT1A1. We concluded that the metabolic pathways of oxidation, hydrolysis and acetylation are relevant to the formation of bulky DNA adducts. This could suggest a potential involvement of aromatic compounds in the formation of such adducts; however, given lack of specificity of the post-labeling assay, a firm conclusion cannot be drawn.

  6. S-arylcysteine-keratin adducts as biomarkers of human dermal exposure to aromatic hydrocarbons.

    PubMed

    Kang-Sickel, Juei-Chuan C; Fox, Donii D; Nam, Tae-Gyu; Jayaraj, Karupiah; Ball, Louise M; French, John E; Klapper, David G; Gold, Avram; Nylander-French, Leena A

    2008-04-01

    To measure biomarkers of skin exposure to ubiquitous industrial and environmental aromatic hydrocarbons, we sought to develop an ELISA to quantitate protein adducts of metabolites of benzene and naphthalene in the skin of exposed individuals. We hypothesized that electrophilic arene oxides formed by CYP isoforms expressed in the human skin react with nucleophilic sites on keratin, the most abundant protein in the stratum corneum that is synthesized de novo during keratinocyte maturation and differentiation. The sulfhydryl groups of cysteines in the head region of the keratin proteins 1 (K1) and 10 (K10) are likely targets. The following synthetic S-arylcysteines were incorporated into 10-mer head sequences of K1 [GGGRFSS( S-aryl-C)GG] and K10 [GGGG( S-aryl-C)GGGGG] to form the predicted immunogenic epitopes for antibody production for ELISA: S-phenylcysteine-K1 (SPK1), S-phenylcysteine-K10 (SPK10), S-(1-naphthyl)cysteine-K1 (1NK1), S-(1-naphthyl)cysteine-K10 (1NK10), S-(2-naphthyl)cysteine-K1 (2NK1), and S-(2-naphthyl)cysteine-K10 (2NK10). Analysis by ELISA was chosen based on its high throughput and sensitivity, and low cost. The synthetic modified oligopeptides, available in quantity, served both as immunogens and as chemical standards for quantitative ELISA. Polyclonal rabbit antibodies produced against the naphthyl-modified keratins reacted with their respective antigens with threshold sensitivities of 15-31 ng/mL and high specificity over a linear range up to 500 ng/mL. Anti- S-phenylcysteine antibodies were not sufficiently specific or sensitive toward the target antigens for use in ELISA under our experimental conditions. In dermal tape-strip samples collected from 13 individuals exposed to naphthalene-containing jet fuel, naphthyl-conjugated peptides were detected at levels from 0.343 +/- 0.274 to 2.34 +/- 1.61 pmol adduct/microg keratin but were undetectable in unexposed volunteers. This is the first report of adducts of naphthalene (or of any polycyclic

  7. Aromatic adducts and lung cancer risk in the European Prospective Investigation into Cancer and Nutrition (EPIC) Spanish cohort.

    PubMed

    Gilberson, Tamra; Peluso, Marco E M; Munia, Armelle; Luján-Barroso, Leila; Sánchez, María-José; Navarro, Carmen; Amiano, Pilar; Barricarte, Aurelio; Quirós, J Ramón; Molina-Montes, Esther; Sánchez-Cantalejo, Emilio; Tormo, María-José; Chirlaque, María-Dolores; Ardanaz, Eva; Dorronsoro, Miren; Confortini, Massimo; Bonet, Catalina; Sala, Núria; González, Carlos A; Agudo, Antonio

    2014-09-01

    In this case-cohort study, we examined the association between bulky DNA adducts and the risk of lung cancer within the European Prospective Investigation into Cancer and Nutrition (EPIC) Spanish cohort with an average 7-year follow-up, including 98 cases of primary lung cancer and 296 subjects randomly selected from the cohort. Aromatic adducts were measured using (32)P-postlabeling in leukocyte DNA from blood samples collected at enrollment. The association between DNA adducts and the risk of lung cancer was estimated using a Cox proportional hazards model with a modified partial likelihood. There was an overall significant increased risk for developing lung cancer when DNA adduct concentrations were doubled, with relative risk (RR) adjusting for all relevant confounders of 1.36 with 95% confidence interval (CI) 1.18-157. There was a significant increased risk for developing lung cancer when DNA adduct concentrations were doubled for current smokers and among subjects exposed to PAH at work; there was also a slightly higher increase among males than females. However, no statistically significant differences were observed for the effect of adduct levels across smoking status, sex or occupational exposure to PAH. A meta-analysis combined four prospective studies, including this study, resulting in a significant association among current smokers, with an overall estimate of 34% increase in the risk of lung cancer when doubling the level of aromatic DNA adducts in leukocytes.

  8. Tracking Matrix Effects in the Analysis of DNA Adducts of Polycyclic Aromatic Hydrocarbons

    PubMed Central

    Klaene, Joshua J.; Flarakos, Caroline; Glick, James; Barret, Jennifer T.; Zarbl, Helmut; Vouros, Paul

    2015-01-01

    LC-MS using electrospray ionization is currently the method of choice in bio-organic analysis covering a wide range of applications in a broad spectrum of biological media. The technique is noted for its high sensitivity but one major limitation which hinders achievement of its optimal sensitivity is the signal suppression due to matrix inferences introduced by the presence of co-extracted compounds during the sample preparation procedure. The analysis of DNA adducts of common environmental carcinogens is particularly sensitive to such matrix effects as sample preparation is a multistep process which involves “contamination” of the sample due to the addition of enzymes and other reagents for digestion of the DNA in order to isolate the analyte(s). This problem is further exacerbated by the need to reach low levels of quantitation (LOQ in the ppb level) while also working with limited (2-5 μg) quantities of sample. We report here on the systematic investigation of ion signal suppression contributed by each individual step involved in the sample preparation associated with the analysis of DNA adducts of polycyclic aromatic hydrocarbon (PAH) using as model analyte dG-BaP, the deoxyguanosine adduct of benzo[a]pyrene (BaP). The individual matrix contribution of each one of these sources to analyte signal was systematically addressed as were any interactive effects. The information was used to develop a validated analytical protocol for the target biomarker at levels typically encountered in vivo using as little as 2 μg of DNA and applied to a dose response study using a metabolically competent cell line. PMID:26607319

  9. Toxicokinetics of DNA adducts and biliary fluorescent aromatic compounds in fish exposed to PAC-contaminated sediments

    SciTech Connect

    French, B.; Reichert, W.L.; Hom, T.; Sanborn, H.R.; Stein, J.E.

    1995-12-31

    Exposure of fish to polycyclic aromatic compounds (PACs) can be assessed by measuring fluorescent aromatic compounds (FACs) in bile or xenobiotic-DNA adducts in liver. Acute exposures in fish to model PACs or PAC contaminated sediment extracts have shown dose-responsive increases in levels of DNA adducts and biliary FACS. FAC levels have been shown to decline rapidly after exposure, whereas a substantial proportion of DNA adducts persist. However, the time and dose responses of these biomarkers with chronic exposure to sediment-associated PACs have not been examined in fish. In this study, the authors examined the effects of varying the PAC concentrations and length of exposure on levels of DNA adducts and biliary FACs in English sole (Pleuronectes vetulus) exposed for up to 5 weeks to reference sediment amended with PAC-contaminated sediment from Eagle Harbor, WA. DNA adduct levels increased linearly with both PAC concentration and length of exposure, while biliary FAC concentrations were responsive to PAC levels but had attained steady-state concentrations after 2 weeks of exposure. Further, levels of DNA adducts and biliary FACs in feral fish captured from Eagle Harbor were within the ranges of levels found in the laboratory-exposed fish. Comparison of the data from field and laboratory-exposed fish strengthened the finding that hepatic DNA adducts accumulated with chronic exposure. The results showing accumulation of hepatic DNA adducts in English sole during continuous exposure to PACs is consistent with previous studies showing a relatively low rate of DNA repair in fish.

  10. Fluorescence line narrowing spectrometry of nucleoside-polycyclic aromatic hydrocarbon adducts on thin-layer chromatographic plates

    SciTech Connect

    Cooper, R.S.; Jankowiak, R.; Hayes, J.M.; Pei-qi, L.; Small, G.J.

    1988-12-15

    Fluorescence line narrowing spectrometry (FLNS) is applied to a polycyclic aromatic hydrocarbon-nucleoside adduct sorbed on a thin-layer chromatography (TLC) plate. A calibration curve over more than 5 decades of concentration is presented and yields a detection limit of /approximately/ 10 fmol. The effects of nonphotochemical hole burning (NPHB) are investigated and discussed. Results indicate that FLN spectrometry can be interfaced with the /sup 32/P-postlabeling procedure to provide for high sensitivity and selectivity analysis of TLC spots associated with fluorescing nucleotide adducts.

  11. Relationships among Polycyclic Aromatic Hydrocarbon–DNA Adducts, Proximity to the World Trade Center, and Effects on Fetal Growth

    PubMed Central

    Perera, Frederica P.; Tang, Deliang; Rauh, Virginia; Lester, Kristin; Tsai, Wei Yann; Tu, Yi Hsuan; Weiss, Lisa; Hoepner, Lori; King, Jeffrey; Del Priore, Giuseppe; Lederman, Sally Ann

    2005-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are toxic pollutants released by the World Trade Center (WTC) fires and various urban combustion sources. Benzo[a]pyrene (BaP) is a representative member of the class of PAHs. PAH–DNA adducts, or BaP–DNA adducts as their proxy, provide a measure of chemical-specific genetic damage that has been associated with increased risk of adverse birth outcomes and cancer. To learn whether PAHs from the WTC disaster increased levels of genetic damage in pregnant women and their newborns, we analyzed BaP–DNA adducts in maternal (n = 170) and umbilical cord blood (n = 203) obtained at delivery from nonsmoking women who were pregnant on 11 September 2001 and were enrolled at delivery at three downtown Manhattan hospitals. The mean adduct levels in cord and maternal blood were highest among newborns and mothers who resided within 1 mi of the WTC site during the month after 11 September, intermediate among those who worked but did not live within this area, and lowest in those who neither worked nor lived within 1 mi (reference group). Among newborns of mothers living within 1 mi of the WTC site during this period, levels of cord blood adducts were inversely correlated with linear distance from the WTC site (p = 0.02). To learn whether PAHs from the WTC disaster may have affected birth outcomes, we analyzed the relationship between these outcomes and DNA adducts in umbilical cord blood, excluding preterm births to reduce variability. There were no independent fetal growth effects of either PAH–DNA adducts or environmental tobacco smoke (ETS), but adducts in combination with in utero exposure to ETS were associated with decreased fetal growth. Specifically, a doubling of adducts among ETS-exposed subjects corresponded to an estimated average 276-g (8%) reduction in birth weight (p = 0.03) and a 1.3-cm (3%) reduction in head circumference (p = 0.04). The findings suggest that exposure to elevated levels of PAHs, indicated by PAH

  12. BINDING OF CARCINOGENS TO DNA AND COVALENT ADDUCTS DNA DAMAGE - PAH, AROMATIC AMINES, NITRO-AROMATIC COMPOUNDS, AND HALOGENATED COMPOUNDS

    EPA Science Inventory

    DNA adducts are the covalent addition products resulting from binding of reactive chemical species to DNA bases. The cancer initiating role of DNA adducts is well-established, and is clearly reflected in the high cancer incidence observed in individuals with deficiencies in any o...

  13. Solid-matrix fluorescence quenching of benzo[e]pyrene and (+/-)-anti-dibenzo[a, l]pyrene diolepoxide-DNA adducts.

    PubMed

    Thompson, Allison L; Hurtubise, Robert J

    2005-01-01

    The solid-matrix fluorescence (SMF) quenching of benzo[e]pyrene and (+/-)-anti-dibenzo[a, l]pyrene-11,12-diol-13,14-epoxide ((+/-)-antiDB[a, l]PDE)-DNA adducts with thallium nitrate (TlNO(3)) and sodium iodide (NaI) was examined and several SMF quenching models were developed. The SMF quenching data for B[e]P with either TlNO(3) or NaI fit a two-independent-binding-site model. However, the SMF quenching of (+/-)-anti-DB[a, l]PDE-DNA adducts with TlNO(3) fits a sphere of action model, but quenching with NaI was modeled with the two-independent-binding-site model. The data were compared with earlier SMF quenching data for 7,8,9,10-tetrahydroxytetrahydro-benzo[a]pyrene (tetrol I-1) and (+/-)-anti-benzo[a]pyrene-trans-7,8-dihydrodiol-9,10-epoxide ((+/-)-anti-BPDE)DNA adducts. The interpretation of the SMF quenching data for the (+/-)-anti-DB[a, l]PDE-DNA adducts was distinctively different than the interpretation of the SMF quenching data for the (+/-)-antiBPDE-DNA adducts. This initial study shows that SMF quenching has the potential to characterize polycyclic aromatic hydrocarbonDNA adducts with different numbers of aromatic rings. In addition, the data indicated that external and intercalated DNA adducts interacted with heavy-atom salts in dissimilar fashions. The new SMF methodology developed is useful for the characterization of both polycyclic aromatic hydrocarbon-DNA adducts and metabolites from polycyclic aromatic hydrocarbons.

  14. THE EFFECT OF ROUTE OF ADMINISTRATION OF POLYCYCLIC AROMATIC HYDROCARBONS ON DNA ADDUCTION AND CYTOGENETIC DAMAGE IN PERIPHERAL BLOOD LYMPHOCYTES OF MICE AND RATS

    EPA Science Inventory

    The effect of route of administration of polycyclic aromatic hydrocarbons on DNA adduction and cytogenetic damage in peripheral blood lymphocytes of mice and rats

    Experiments were designed to investigate how the route of exposure to polycyclic
    aromatic hydrocarbons (PA...

  15. THE EFFECT OF ROUTE OF ADMINISTRATION OF POLYCYCLIC AROMATIC HYDROCARBONS ON DNA ADDUCTION AND CYTOGENETIC DAMAGE IN PERIPHERAL BLOOD LYMPHOCYTES OF MICE AND RATS

    EPA Science Inventory

    The effect of route of administration of polycyclic aromatic hydrocarbons on DNA adduction and cytogenetic damage in peripheral blood lymphocytes of mice and rats

    Experiments were designed to investigate how the route of exposure to polycyclic
    aromatic hydrocarbons (PA...

  16. Relationship between Polycyclic Aromatic Hydrocarbon–DNA Adducts, Environmental Tobacco Smoke, and Child Development in the World Trade Center Cohort

    PubMed Central

    Perera, Frederica P.; Tang, Deliang; Rauh, Virginia; Tu, Yi Hsuan; Tsai, Wei Yann; Becker, Mark; Stein, Janet L.; King, Jeffrey; Priore, Giuseppe Del; Lederman, Sally Ann

    2007-01-01

    Background Polycyclic aromatic hydrocarbons (PAHs), including benzo[a]pyrene (BaP), are air pollutants released by the World Trade Center (WTC) fires and urban combustion sources. BaP–DNA adducts provide a measure of PAH-specific genetic damage, which has been associated with increased risk of adverse birth outcomes and cancer. We previously reported that levels of BaP–DNA adducts in maternal and umbilical cord blood obtained at delivery were elevated among subjects who had resided within 1 mile of the WTC site during the month after 9/11; and that elevated blood adducts in combination with in utero exposure to environmental tobacco smoke (ETS) were significantly associated with decreased fetal growth. Objective Our aim was to assess possible effects of prenatal exposure to WTC pollutants on child development. Methods After 11 September 2001, we enrolled a cohort of nonsmoking pregnant women who delivered at three lower Manhattan hospitals. We have followed a subset of children through their third birthdays and measured cognitive and motor development using the Bayley-II Scales of Child Development (BSID-II). Results In multivariate analyses, we found a significant interaction between cord blood adducts and in utero exposure to ETS on mental development index score at 3 years of age (p = 0.02, n = 98) whereas neither adducts nor ETS alone was a significant predictor of (BSID-II) cognitive development. Conclusion Although limited by small numbers, these results suggest that exposure to elevated levels of PAHs in conjunction with prenatal ETS exposure may have contributed to a modest reduction in cognitive development among cohort children. PMID:17938742

  17. Synthesis of polycyclic aromatic hydrocarbon adducts of adenine in nucleosides and oligonucleotides

    SciTech Connect

    Kim, S.J.

    1992-01-01

    PAHs are activated metabolically to electrophilic intermediates such as diol epoxides, which bind to cellular macromolecules, particularly DNA. The dominant paradigm for the etiology of chemically induced cancer involves alterations in the structure of DNA which can cause replication errors. Synthesis of oligonucleotides bearing regiochemically and stereochemically defined PAH adducts is a prerequisite to any study of the relationships of adduct structure to mutagenicity. The first chapter introduces the history of PAH carcinogenesis studies. The second chapter contains the synthetic methodology for preparation of deoxyadenosine adducts of PAHs: benzo[a]pyrene, benz[a]anthracene, and benzo[c]phenanthrene. The nucleoside adducts were synthesized efficiently via the reaction of racemic aminotriol derivatives of PAHs with 6-fluoropurine deoxyriboside. The enantiopure PAH adducts of deoxyadenosine were obtained by HPLC separation of the diastereomers which were characterized by [sup 1]H and 2D NMR, CD, UV, and Mass spectroscopy. The third chapter describes syntheses of oligonucleotides bearing regiochemically and stereochemically defined PAH adducts of benzo[a]pyrene and benz[a]anthracene. A post-oligomerization strategy was used in which the condensation reaction between the aminotriol and a fluoronucleoside was carried out after assembling of the oligomer but before the final deprotection step. The fourth chapter describes an efficient synthesis of (+) and ([minus]) benzo[a]pyrene adducts of deoxyadenosine 3[prime]-phosphate which will be valuable as authentic standards in the Randerath [sup 32]P postlabeling procedure for identification of DNA adducts. In chapter five, a synthetic approach to PAH adducts of deoxyguanosine is discussed. A selective deprotection method is explored in which the oligonucleotide is assembled in the normal fashion except for the exocyclic amino group of the target nucleotide being protected with a labile protecting group.

  18. DNA-adducts in subjects exposed to urban air pollution by benzene and polycyclic aromatic hydrocarbons (PAHs) in Cotonou, Benin.

    PubMed

    Ayi-Fanou, Lucie; Avogbe, Patrice H; Fayomi, Benjamin; Keith, Gerard; Hountondji, Codjo; Creppy, Edmond E; Autrup, Herman; Rihn, Bertrand Henri; Sanni, Ambaliou

    2011-02-01

    Air pollution effect on humans represents a major public health problem. Exposure to genotoxic compounds in the ambient air is evaluated using different biomarkers. In the present study we assessed DNA-adducts levels in apparently healthy people living and working in the city of Cotonou (Benin) in which exposure to air pollutants such as benzene and polycyclic aromatic hydrocarbons (PAHs) mainly benzo(a)pyrene has been evidenced. Rural inhabitants were enrolled as control group. Taxi-motorbike drivers, street food vendors, and gasoline salesmen were recruited in Cotonou whereas suburban residents were recruited in Godomey, 12 km from Cotonou. We found that taxi-motorbike drivers, roadside residents, street vendors, taxi-motor-bike drivers and gasoline sellers had significantly higher levels of DNA-adducts than suburban and village inhabitants (P < 0.001; post hoc, LSD). Means values were 24.6 ± 6.4, 23.78 ± 6.9, 34.7 ± 9.8, and 37.2 ± 8.1 in the exposed groups versus 2.1 ± 0.6 and 3.1 ± 0.8 adducts/10(8) nucleotides, in the two control groups, respectively. We did not find any significant difference within the high exposure groups and inside low exposure subgroups (namely suburban residents and villagers) because the mean individual exposure values to both PAHs and benzene were similar among subjects exposed in the city of Cotonou and those in suburban and village areas. However, there is significant interindividual variations in adducts levels that may reflect variation of genetic susceptibility factors. Ranges of adduct level/10(8) nucleotides were: 1-69, 1-76, 3-169, 4-124, 0-9, 0-8 adducts/10(8) for taxi-motorbike drivers, roadside residents, street vendors, gasoline sellers, suburban and village inhabitants, respectively. Our study demonstrated a clear-cut elevated level of DNA adducts in city residents than in none exposed people (or very low exposure levels people) and designate these city residents groups as people at risks for the chronic diseases

  19. [Mass spectrometric analysis of polycyclic aromatic hydrocarbons adducted to DNA]. Final report

    SciTech Connect

    Barofsky, D.F.

    1992-12-31

    Studies described herein sought and to synthesize PAH-adducted residues of DNA to serve as models for carrying out the mass spectrometric studies; to construct and test a high performance, pulsed ion bombardment, time-of-flight (TOF) mass spectrometer; to initiate an investigation of the efficacy of using thin wire sample holders to increase sensitivity and focused ion beam bombardment to increase ion yield and ion transmission; and to initiate an investigation of sensitivity enhancing matrices for PAH-adducted DNA.

  20. Protein adducts as biomarkers of exposure to aromatic diisocyanates in workers manufacturing polyurethane (PUR) foam.

    PubMed

    Säkkinen, Kirsi; Tornaeus, Jarkko; Hesso, Antti; Hirvonen, Ari; Vainio, Harri; Norppa, Hannu; Rosenberg, Christina

    2011-04-01

    This work was undertaken to investigate the usefulness of diisocyanate-related protein adducts in blood samples as biomarkers of occupational exposure to toluene diisocyanate (TDI; 2,4- and 2,6-isomers) and 4,4'-methylenediphenyl diisocyanate (MDI). Quantification of adducts as toluene diamines (TDAs) and methylenedianiline (MDA) was performed on perfluoroacylated derivatives by gas chromatography-mass spectrometry (GC-MS/MS) in negative chemical ionisation mode. TDI-derived adducts were found in 77% of plasma and in 59% of globin samples from exposed workers manufacturing flexible polyurethane foam. The plasma levels ranged from 0.003 to 0.58 nmol mL(-1) and those in globin from 0.012 to 0.33 nmol g(-1). The 2,6-isomer amounted to about two-thirds of the sum concentration of TDA isomers. MDI-derived adducts were detected in 3.5% of plasma and in 7% of globin samples from exposed workers manufacturing rigid polyurethane foam. A good correlation was found between the sum of TDA isomers in urine and that in plasma. The relationship between globin adducts and urinary metabolites was ambiguous. Monitoring TDI-derived TDA in plasma thus appears to be an appropriate method for assessing occupational exposure. Contrary to TDI exposure, adducts in plasma or globin were not useful in assessing workers' exposure to MDI. An important outcome of the study was that no amine-related adducts were detected in globin samples from TDI- or MDI-exposed workers, alleviating concerns that TDI or MDI might pose a carcinogenic hazard. Further studies are nevertheless required to judge whether diisocyanates per se could be such a hazard.

  1. Stereoselective release of polycyclic aromatic hydrocarbon-deoxyadenosine adducts from DNA by the 32P postlabeling and deoxyribonuclease I/snake venom phosphodiesterase digestion methods

    SciTech Connect

    Cheh, A.M.; Yagi, H.; Jerina, D.M. )

    1990-11-01

    The restricted ability of deoxyribonuclease I/snake venom phosphodiesterase digestion to liberate deoxyadenosine (dA) nucleotide adducts of polycyclic aromatic hydrocarbons from DNA, first observed by Dipple and Pigott with the bay-region diol epoxide adducts of 7,12-dimethylbenz(a)anthracene, has been observed with the dA adducts of benz(a)anthracene and benzo(c)phenanthrene diol epoxides. The micrococcal nuclease/spleen phosphodiesterase digestion used in the original 32P postlabeling procedure developed by Randerath to determine DNA adducts also failed to liberate dA nucleotide adducts quantitatively. Thus either method can potentially lead to an underestimation of the extent to which dA has been modified in DNA. The two digestion procedures exhibit systematic and mostly opposite stereoselectivity in the pattern of which dA adducts are resistant to digestion, which suggest that these adducts may have preferred orientations within modified DNA that are determined by whether they have the R or S configuration at C-1, the point of attachment between the exocyclic amino group of dA and the hydrocarbon; this in turn is dictated by the configuration about the precursor benzylic epoxide carbon and the cis versus trans nature of epoxide opening during adduct formation.

  2. THE EFFECT OF ROUTE OF ADMINISTRATION OF POLYCYCLIC AROMATIC HYDROCARBONS ON DNA ADDUCTION AND CYTOGENETIC DAMAGE IN PERIPHERAL BLOOD LYMPHOCYTES OF MICE AND RATS

    EPA Science Inventory

    Experiments were designed to investigate how the route of exposure to polycyclic aromatic hydrocarbons (PAHs) in mice and rats affects the induction of cytogenetic endpoints and DNA adduction. Both mice and rats were exposed to 100 mg/kg of benz[a]anthracene (B[a]A), benzo[b]fl...

  3. THE EFFECT OF ROUTE OF ADMINISTRATION OF POLYCYCLIC AROMATIC HYDROCARBONS ON DNA ADDUCTION AND CYTOGENETIC DAMAGE IN PERIPHERAL BLOOD LYMPHOCYTES OF MICE AND RATS

    EPA Science Inventory

    Experiments were designed to investigate how the route of exposure to polycyclic aromatic hydrocarbons (PAHs) in mice and rats affects the induction of cytogenetic endpoints and DNA adduction. Both mice and rats were exposed to 100 mg/kg of benz[a]anthracene (B[a]A), benzo[b]fl...

  4. Structures of polycyclic aromatic hydrocarbon adducts by molecular mechanics and molecular dynamics simulations

    SciTech Connect

    Singh, S.B.

    1992-01-01

    The structures of the adducts of (+)- and (-)trans-7,8,dihydroxy-anti-9,10-epoxy-7,8,9,10-tetrahydrobenzo (a)pyrene (anti-BPDE) formed by trans addition to N[sup 2] of guanine have been of great interest because the high biological activity of BPDE in mammalian mutagenesis and tumorigenesis has been attributed to the predominant (+)-adduct, while the (-)-adduct is inactive. Molecular mechanics and dynamics calculations have been employed to elucidate the structural difference between this mirror image adduct pair in a duplex dodecamer, d(5' GCGCGCG-(BPDE)CGCGC3') [center dot] d(5'GCGCGCGCGCGC3'). Minimized potential energy calculations using the program DUPLEX were employed to locate starting structures for the dynamics. Three types of structures were found in the energy minimized conformation space searches for each enantiomer: pyrenyl moiety in the minor groove of a Watson-Crick base paired B-DNA duplex, pyrenyl moiety in the major groove of a B-DNA duplex with syn guanine and Hoogsteen base pairs at the modification site, and intercalation type structures. The minor groove structure is energetically preferred for the (+) enantiomer while both minor groove and major groove structures are favored and of comparable energy in the (-) enantiomer. These energy-minimized duplex dodecamers, as well as an unmodified B-DNA control of the same sequence, were subjected to 100 ps molecular dynamics simulations with solvent and salt with the program AMBER. The duplex dodecamer, d(CGCGAATTCGCG)[sub 2], was subjected to a similar simulation using the crystal structure as starting coordinates. Detailed analysis of the dynamic evolution of the conformational and the helical parameters of all the dodecamer simulations were carried out with Molecular Dynamics Analysis Toolchest.

  5. Development and validation of a direct sandwich chemiluminescence immunoassay for measuring DNA adducts of benzo[a]pyrene and other polycyclic aromatic hydrocarbons

    PubMed Central

    Georgiadis, Panagiotis; Kovács, Katalin; Kaila, Stella; Makedonopoulou, Paraskevi; Anna, Livia; Poirier, Miriam C.; Knudsen, Lisbeth E.; Schoket, Bernadette; Kyrtopoulos, Soterios A.

    2012-01-01

    We have developed and validated a sandwich chemiluminescence immunoassay (SCIA) which measures polycyclic aromatic hydrocarbon (PAH)–DNA adducts combining high throughput and adequate sensitivity, appropriate for evaluation of adduct levels in human population studies. Fragmented DNA is incubated with rabbit antiserum elicited against DNA modified with r7,t8-dihydroxy-t-9,10-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene (BPDE) and subsequently trapped by goat anti-rabbit IgG bound to a solid surface. Anti-single-stranded (ss) DNA antibodies binds in a quantity proportional to the adduct levels and is detected by chemiluminescence. The BPDE–DNA SCIA has a limit of detection of 3 adducts per 109 nucleotides with 5 μg DNA per well. We have validated the BPDE–DNA SCIA using DNA modified in vitro, DNA from benzo[a]pyrene (BP)-exposed cultured cells and mice. The levels of adduct measured by SCIA were lower (30–60%) than levels of bulky DNA adducts measured in the same samples by 32P-postlabelling. The BPDE–DNA SCIA also detected adducts produced in vivo by PAHs other than BP. When blood DNA samples from maternal/infant pairs were assayed by BPDE–DNA SCIA, the adduct levels obtained were significantly correlated. However, there was no correlation between 32P-postlabelling and SCIA values for the same samples. The SCIA can be extended to any DNA adduct and is expected to provide, when fully automated, a valuable high-throughput approach in large-scale population studies. PMID:22610669

  6. Comparative analysis of aromatic DNA adducts in fish from polluted and unpolluted areas by the sup 32 P-postlabeling analysis

    SciTech Connect

    Tsungyun Liu; Shuling Cheng; Chinwen Chi ); Tzuuhuei Ueng; Yunefang Ueng )

    1991-11-01

    The {sup 32}P-postlabeling technique, developed by Randerath and his colleagues, is a highly sensitive assay to detect the damaged DNA as DNA-carcinogen adduct. Consequently, measurement of this DNA carcinogen adduct concentrations in target tissues of organisms may provide a key biologic end-point of exposure to environmental carcinogens. In this study the authors analyze the hepatic DNA from a bottom-feeding fish, tilapia (Tilapia mossambica), sampled from the down stream Damsui River where fish are exposed to high levels of polycyclic aromatic hydrocarbons (PAH) in sediment and from the upstream Fe-Tsui reservoir where the water has been used as the source of drinking water for Taipei Metropolitan area. In doing so, they will be able to determine whether this {sup 32}P-postlabeling analysis of hepatic DNA from the bottom-feeding tilapia can be used to monitor large molecule aromatic carcinogens in the environment.

  7. Effect of C60 adducts on the dynamic structure of aromatic solvation shells

    NASA Astrophysics Data System (ADS)

    Peerless, James S.; Bowers, G. Hunter; Kwansa, Albert L.; Yingling, Yaroslava G.

    2017-06-01

    We report herein on the use of all-atom molecular dynamics simulations to investigate the solvation environment of C60 and four C60-derived fullerenes immersed in a variety of aromatic solvents. Utilizing a recently developed solvation shell analysis technique that quantifies the spatial relationships between fullerenes and solvent on a molecular level, we show that the number of fullerene substituents and solvent chemistry are crucial determinants of the solvation shell structure and thus fullerene solvation behavior. Specifically, it is shown for the derivatives investigated that the number of fullerene substituents is more critical to solvation behavior than the substituent chemistry.

  8. Micronuclei related to anti-B[a]PDE-DNA adduct in peripheral blood lymphocytes of heavily polycyclic aromatic hydrocarbon-exposed nonsmoking coke-oven workers and controls.

    PubMed

    Pavanello, Sofia; Kapka, Lucyna; Siwinska, Ewa; Mielzyñska, Danuta; Bolognesi, Claudia; Clonfero, Erminio

    2008-10-01

    Micronuclei (MN) frequency associated to biologically effective dose of polycyclic aromatic hydrocarbons [PAH; anti-benzo[a]pyrene diolepoxide (B[a]PDE)-DNA] within the same subjects' peripheral blood lymphocytes (PBL) was evaluated. Study subjects were nonsmoking male Polish coke-oven workers (n=49) and matched controls (n=45) verified for PAH exposure by urinary 1-pyrenol. We found that coke-oven workers, heavily exposed to PAHs (80% workers exceeded the urinary 1-pyrenol biological exposure index value), presented significantly higher MN frequency in PBLs than controls (P<0.01). Substantial difference was also found for adduct levels in PBLs (P<0.01). Increase in MN levels was significantly related to anti-B[a]PDE-DNA formation, key adduct of the ultimate carcinogenic metabolite of B[a]P (n=94; r=0.47; P<0.001). The dose-response relationship was improved when subjects with adduct levels above the 3rd tertile (>or=4.35 adducts/10(8) nucleotides) were excluded (n=61; r=0.69; P<0.001). Saturation of adduct/MN formation at high levels may disturb the underlying relationship. Linear multiple regression analysis, without subjects of 3rd tertile adduct level (n=61), revealed that adduct formation (t=4.61; P<0.001), but not 1-pyrenol, was the significant determinant in increasing MN. In conclusion, the increase in MN frequency is mainly related to the specific anti-B[a]PDE-DNA formation within PBLs of the same subject. Our results substantiate, with the use of an early indicator of biological effect as well, that workers are at higher cancer risk than controls.

  9. ASSOCIATION BETWEEN POLYCYCLIC AROMATIC HYDROCARBON-DNA ADDUCT LEVELS IN MATERNAL AND NEWBORN WHITE BLOOD CELLS AND GLUTATHIONE S-TRANSFERASE P1 AND CYP1A1 POLYMORPHISMS. (R827027)

    EPA Science Inventory

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  10. Bulky DNA adducts in human sperm associated with semen parameters and sperm DNA fragmentation in infertile men: a cross-sectional study

    PubMed Central

    2013-01-01

    Background DNA adducts are widely used marker of DNA damage induced by environmental pollutants. The present study was designed to explore whether sperm polycyclic aromatic hydrocarbon-DNA adducts were associated with sperm DNA integrity and semen quality. Methods A total of 433 Han Chinese men were recruited from an infertility clinic. Immunofluorescence was applied to analyze sperm PAH-DNA adducts. Sperm DNA fragmentation was detected by terminal deoxynucleotidyl transferase (Tdt)-mediated dUTP nick end labelling (TUNEL) assay. Results After adjustment for potential confounders using linear regression, sperm PAH-DNA adducts were negatively associated with sperm concentration, total sperm count, sperm motility, and curvilinear velocity (VCL). In addition, a positive relationship between sperm PAH-DNA adducts and sperm DNA fragmentation was found. Conclusions Our findings suggested an inverse association between sperm PAH-DNA adducts and semen quality, and provided the first epidemiologic evidence of an adverse effect of PAH-DNA adducts on sperm DNA integrity. PMID:24073787

  11. Conditions for sample preparation and quantitative HPLC/MS-MS analysis of bulky adducts to serum albumin with diolepoxides of polycyclic aromatic hydrocarbons as models.

    PubMed

    Westberg, Emelie; Hedebrant, Ulla; Haglund, Johanna; Alsberg, Tomas; Eriksson, Johan; Seidel, Albrecht; Törnqvist, Margareta

    2014-02-01

    Stable adducts to serum albumin (SA) from electrophilic and genotoxic compounds/metabolites can be used as biomarkers for quantification of the corresponding in vivo dose. In the present study, conditions for specific analysis of stable adducts to SA formed from carcinogenic polycyclic aromatic hydrocarbons (PAH) were evaluated in order to achieve a sensitive and reproducible quantitative method. Bulky adducts from diolepoxides (DE) of PAH, primarily DE of benzo[a]pyrene (BPDE) and also DE of dibenzo[a,l]pyrene (DBPDE) and dibenzo[a,h]anthracene (DBADE), were used as model compounds. The alkylated peptides obtained after enzymatic hydrolysis of human SA modified with the different PAHDE were principally PAHDE-His-Pro, PAHDE-His-Pro-Tyr and PAHDE-Lys. Alkaline hydrolysis under optimised conditions gave the BPDE-His as the single analyte of alkylated His, but also indicated degradation of this adduct. It was not possible to obtain the BPDE-His as one analyte from BPDE-alkylated SA through modifications of the enzymatic hydrolysis. The BPDE-His adduct was shown to be stable during the weak acidic conditions used in the isolation of SA. Enrichment by HPLC or SPE, but not butanol extraction, gave good recovery, using Protein LoBind tubes. A simple internal standard (IS) approach using SA modified with other PAHDE as IS was shown to be applicable. A robust analytical procedure based on digestion with pronase, enrichment by HPLC or SPE, and analysis with HPLC/MS-MS electrospray ionisation was achieved. A good reproducibility (coefficient of variation (CV) 11 %) was obtained, and the achieved limit of detection for the studied PAHDE, using standard instrumentation, was approximately 1 fmol adduct/mg SA analysing extract from 5 mg SA.

  12. Aromatic DNA adducts and number of lung cancer risk alleles in Map-Ta-Phut Industrial Estate workers and nearby residents.

    PubMed

    Peluso, Marco; Srivatanakul, Petcharin; Jedpiyawongse, Adisorn; Sangrajrang, Suleeporn; Munnia, Armelle; Piro, Sara; Ceppi, Marcello; Boffetta, Paolo; Godschalk, Roger W L; van Schooten, Frederik J

    2013-01-01

    The Map-Ta-Phut Industrial Estate (MIE) in Rayong, Thailand, is the location of one of the largest industrial complexes in southeastern Asia. The MIE complex produces a mixture of air pollutants, including polycyclic aromatic hydrocarbons, compounds capable to induce the generation of DNA adducts. DNA adducts are considered to be a biomarker of carcinogen exposure; however, its production can be modulated by genetic susceptibility. Thus, we analysed the influence of EPHX1 His139Arg (A>G, rs2234922) and NQO1 Pro187Ser (C>T, rs1800566) involved in the metabolism of polycyclic aromatic hydrocarbons; MnSOD(2) Val16Ala (C>T, rs1799725) a gene that acts against the free radical generation; APE1/Ref-1 Asp148Glu (T>G, rs3136820) a gene involved in the repair of DNA, and in the control of cell-cycle and apoptosis on leucocyte DNA adducts in 77 MIE workers, 69 Map-Ta-Phut residents, and 50 rural controls, Rayong, Thailand. We searched for associations with the 'sum of at-risk alleles' by combining the variant alleles of EPHX1, NQO1 and MnSOD(2) together with the wild-type allele of APE1, since they appeared to influence lung cancer risk. Although our findings revealed significant associations between DNA adducts and the EPHX1 His139Arg and NQO1 Pro187Ser polymorphisms, the combination of at-risk alleles was found to affect DNA damage much stronger. DNA adducts were significantly increased in the individuals bearing 4 and ≥ 5 at-risk alleles [mean ratio (MR) = 1.55, 95% CI 1.10-2.18, P = 0.012, and MR = 2.11, 95% CI 1.27-3.51, P = 0.004, respectively)]. After correction for residence/employment categorisation, a significant increment was present in the MIE workers with ≥ 5 alleles (MR = 2.88, 95% CI 1.46-5.71, P = 0.003). Our data indicate relationships between the generation of DNA adducts and the enzymatic activities of EPHX and NQO1. The combination of unfavourable genetic variants seems to determine the individuals' susceptibility, rather than a single polymorphism.

  13. γ-Selective Cross-Coupling of Allylic Silanolate Salts with Aromatic Bromides Using Trialkylphosphonium Tetrafluoroborate Salts Prepared Directly from Phosphine•Borane Adducts

    PubMed Central

    Denmark, Scott E.; Werner, Nathan S.

    2011-01-01

    The γ-selective, palladium-catalyzed cross-coupling of sodium (Z)-2-butenyldiethylsilanolate with a variety of aromatic bromides is reported. The protocol provides high yields (73–94%) and site-selectivity (γ/α, 25:1–>99:1) in the coupling of electron-rich, electron-poor, sterically hindered, and heteroaromatic bromides. The use of a configurationally homogeneous (Z)-silanolate, nontransferable ethyl groups, and a sterically bulky trialkylphosphonium tetrafluoroborate salt (t-BuCy2PH+BF4−) prepared directly from the corresponding air-stable phosphine•borane adduct are critical to the success of the method. PMID:21830766

  14. Associations between Smoking, Polymorphisms in Polycyclic Aromatic Hydrocarbon (PAH) Metabolism and Conjugation Genes and PAH-DNA Adducts in Prostate Tumors Differ by Race

    PubMed Central

    Nock, Nora L.; Tang, Deliang; Rundle, Andrew; Neslund-Dudas, Christine; Savera, Adnan T.; Bock, Cathryn H.; Monaghan, Kristin G.; Koprowski, Allison; Mitrache, Nicoleta; Yang, James J.; Rybicki, Benjamin A.

    2007-01-01

    Polycyclic aromatic hydrocarbon (PAH)-DNA adducts may induce mutations that contribute to carcinogenesis. We evaluated potential associations between smoking and polymorphisms in PAH metabolism [CYP1A1 Ile462Val, CYP1B1 Ala119Ser and Leu432Val, microsomal epoxide hydrolase (mEH) Tyr113His and His139Arg, CYP3A4 A(−392)G] and conjugation [glutathione S-transferase (GST) M1 null deletion, GSTP1 Ile105Val] genes and PAH-DNA adduct levels (measured by immunohistochemistry) in tumor and nontumor prostate cells in 400 prostate cancer cases. Although no statistically significant associations were observed in the total sample, stratification by ethnicity revealed that Caucasian ever smokers compared with nonsmokers had higher adduct levels in tumor cells (mean staining intensity in absorbance units ± SE, 0.1748 ± 0.0052 versus 0.1507 ± 0.0070; P = 0.006), and Caucasians carrying two mEH 139Arg compared with two 139His alleles had lower adducts in tumor (0.1320 ± 0.0129 versus 0.1714 ± 0.0059; P = 0.006) and nontumor (0.1856 ± 0.0184 versus 0.2291 ± 0.0085; P = 0.03) cells. African Americans with two CYP1B1 432Val compared with two 432Ile alleles had lower adducts in tumor cells (0.1600 ± 0.0060 versus 0.1970 ± 0.0153; P = 0.03). After adjusting for smoking status, carrying the putative “high-risk” genotype combination, the faster metabolism of PAH-epoxides to PAH-diol-epoxides (CYP1B1 432Val/Val and mEH 139Arg/Arg) with lower PAH-diol-epoxide conjugation (GSTP1 105Ile/Ile), was associated with increased adducts only in Caucasian nontumor cells (0.2363 ± 0.0132 versus 0.1920 ± 0.0157; P = 0.05). We present evidence, for the first time in human prostate that the association between smoking and PAH-DNA adducts differs by race and is modified by common genetic variants. PMID:17548691

  15. Inhibition of the formation of benzo[a]pyrene adducts to DNA in A549 lung cells exposed to mixtures of polycyclic aromatic hydrocarbons.

    PubMed

    Genies, Camille; Jullien, Amandine; Lefebvre, Emmanuel; Revol, Morgane; Maitre, Anne; Douki, Thierry

    2016-09-01

    Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous pollutants, which exhibit carcinogenic properties especially in lungs. In the present work, we studied the effect of mixtures of 12 PAHs on the A549 alveolar cells. We first assess the ability of each PAH at inducing gene expression of phase I metabolization enzymes and at generating DNA adducts. A good correlation was found between these two endpoints. We then exposed cells to either binary mixtures of the highly genotoxic benzo[a]pyrene (B[a]P) with each PAH or complex mixtures of all studied PAHs mimicking by real emissions including combustion of wood, cigarette smoke, and atmospheres of garage, silicon factory and urban environments. Compared to pure B[a]P, both types of mixtures led to reduced CYP450 activity measured by the EROD test. A similar trend was observed for the formation of DNA adducts. Surprisingly, the complex mixtures were more potent than B[a]P used at the same concentration for the induction of genes coding for CYP. Our results stress the lack of additivity of the genotoxic properties of PAH in mixtures. Interestingly, an opposite synergy in the formation of B[a]P adducts were observed previously in hepatocytes. Our data also show that measurement of the metabolic activity rather than quantification of gene expression reflects the actual bioactivation of PAHs into DNA damaging species.

  16. Exposure of iron foundry workers to polycyclic aromatic hydrocarbons: benzo(a)pyrene-albumin adducts and 1-hydroxypyrene as biomarkers for exposure.

    PubMed Central

    Omland, O; Sherson, D; Hansen, A M; Sigsgaard, T; Autrup, H; Overgaard, E

    1994-01-01

    Exposure to polycyclic aromatic hydrocarbons (PAHs) in foundry workers has been evaluated by determination of benzo(a)pyrene-serum albumin adducts and urinary 1-hydroxypyrene. Benzo(a)pyrene binding to albumin and 1-hydroxypyrene were quantitatively measured by enzyme linked immunosorbent assay (ELISA) and reverse phase high performance liquid chromatography (HPLC), respectively. 70 male foundry workers and 68 matched controls were investigated. High and low exposure groups were defined from breathing zone hygienic samples, consisting of 16 PAH compounds in particulate and gaseous phase. Mean total PAH was 10.40 micrograms/m3 in the breathing zone, and mean dust adsorbed PAH was 0.15 microgram/m. All carcinogenic PAH was adsorbed to dust. Median benzo(a)pyrene-albumin adduct concentrations (10-90% percentiles) were similar in foundry workers (smokers 0.55 (0.27-1.00) and non-smokers 0.58 (0.17-1.15)) pmol/mg albumin and age matched controls (smokers 0.57 (0.16-1.45) and non-smokers 0.70 (0.19-1.55) pmol/mg albumin). Median 1-hydroxypyrene concentrations were significantly higher (P < 0.0001) in smoking and non-smoking foundry workers (0.022 (0.006-0.075) and 0.027 (0.006-0.164)) mumol/mol creatinine than in smoking and non-smoking controls (0 (0-0.022) and 0 (0-0.010) mumol/mol creatinine). Dose-response relations between total PAH, pyrene, carcinogenic PAHs, and 1-hydroxypyrene for smokers, and polycyclic aromatic hydrocarbons adsorbed to dust for non-smokers are suggested. Exposure to PAHs adsorbed to dust showed an additive effect. There was no correlation between the concentrations of 1-hydroxypyrene and benzo(a)pyrene-albumin adducts. The change in 1-hydroxypyrene over a weekend was also studied. Friday morning median 1-hydroxypyrene concentrations were significantly higher in both smokers and non-smokers (0.021 (0-0.075) and 0.027 (0.06-0.164)) mumol/mol creatinine than Monday morning median concentrations (0.007 (0-0.021) and 0.008 (0-0.021) mumol

  17. DNA damage from polycyclic aromatic hydrocarbons measured by benzo[a]pyrene-DNA adducts in mothers and newborns from Northern Manhattan, the World Trade Center Area, Poland, and China.

    PubMed

    Perera, Frederica; Tang, Deliang; Whyatt, Robin; Lederman, Sally Ann; Jedrychowski, Wieslaw

    2005-03-01

    Polycyclic aromatic hydrocarbons (PAH), of which benzo[a]pyrene is a representative member, are combustion-related environmental pollutants and include known carcinogens. Laboratory animal studies indicate that the dose of PAHs to the fetus is on the order of a 10th that to the mother and that there is heightened susceptibility to PAH-induced carcinogenesis during the fetal and infancy periods. Carcinogen-DNA adducts, a measure of procarcinogenic genetic damage, are considered a biomarker of increased cancer risk. Here we compare the levels of benzo[a]pyrene-DNA adducts as a proxy for PAH-DNA damage measured in maternal blood and newborn cord blood obtained at delivery in four different populations of mothers (total of 867) and newborns (total of 822), representing a 30-fold range of exposure to ambient PAHs. The populations include residents in Northern Manhattan, participants in a study of the effects of the World Trade Center disaster, residents in Krakow, Poland, and residents in Tongliang, China. Mean adduct concentrations in both maternal and cord blood and the proportion of samples with detectable adducts, increased across the populations [Northern Manhattan < World Trade Center (WTC) < Krakow < Tongliang], consistent with the trend in estimated ambient exposure to PAHs (P < 0.001). For mothers, the means in the respective populations were Northern Manhattan (0.21 adducts per 10(8) nucleotides), WTC (0.23 adducts per 10(8) nucleotides), Krakow (0.28 adducts per 10(8) nucleotides), Tongliang (0.31 adducts per 10(8) nucleotides); the corresponding means in the newborns were Northern Manhattan (0.23), WTC (0.24), Krakow (0.29), Tongliang (0.31). The percentage of mothers with detectable levels of adducts in the respective populations were Northern Manhattan (36.8%), WTC (57.5%), Krakow (72.9%), Tongliang (73.4%); the corresponding percentages among the newborns were Northern Manhattan (42.4%), WTC (60.6%), Krakow (71.1%), Tongliang (79.5%). Despite the

  18. Combined effects of prenatal polycyclic aromatic hydrocarbons and material hardship on child IQ.

    PubMed

    Vishnevetsky, Julia; Tang, Deliang; Chang, Hsin-Wen; Roen, Emily L; Wang, Ya; Rauh, Virginia; Wang, Shuang; Miller, Rachel L; Herbstman, Julie; Perera, Frederica P

    2015-01-01

    Polycyclic aromatic hydrocarbons are common carcinogenic and neurotoxic urban air pollutants. Toxic exposures, including air pollution, are disproportionately high in communities of color and frequently co-occur with chronic economic deprivation. We examined whether the association between child IQ and prenatal exposure to polycyclic aromatic hydrocarbons differed between groups of children whose mothers reported high vs. low material hardship during their pregnancy and through child age 5. We tested statistical interactions between hardships and polycyclic aromatic hydrocarbons, as measured by DNA adducts in cord blood, to determine whether material hardship exacerbated the association between adducts and IQ scores. Prospective cohort. Participants were recruited from 1998 to 2006 and followed from gestation through age 7 years. Urban community (New York City) A community-based sample of 276 minority urban youth EXPOSURE MEASURE: Polycyclic aromatic hydrocarbon-DNA adducts in cord blood as an individual biomarker of prenatal polycyclic aromatic hydrocarbon exposure. Maternal material hardship self-reported prenatally and at multiple timepoints through early childhood. Child IQ at 7 years assessed using the Wechsler Intelligence Scale for Children. Significant inverse effects of high cord PAH-DNA adducts on full scale IQ, perceptual reasoning and working memory scores were observed in the groups whose mothers reported a high level of material hardship during pregnancy or recurring high hardship into the child's early years, and not in those without reported high hardship. Significant interactions were observed between high cord adducts and prenatal hardship on working memory scores (β = -8.07, 95% CI (-14.48, -1.66)) and between high cord adducts and recurrent material hardship (β = -9.82, 95% CI (-16.22, -3.42)). The findings add to other evidence that socioeconomic disadvantage can increase the adverse effects of toxic physical "stressors" like air pollutants

  19. Human DNA adduct measurements: State of the art

    SciTech Connect

    Poirier, M.C.; Weston, A.

    1996-10-01

    Human DNA adduct formation (covalent modification of DNA with chemical carcinogens) is a promising biomarker for elucidating the molecular epidemiology of cancer. Classes of compounds for which human DNA adducts have been observed include polycyclic aromatic hydrocarbons (PAHs), nitrosamines, mycotoxins, aromatic amines, heterocyclic amines, ultraviolet light, and alkylating cancer chemotherapeutic agents. Most human DNA adduct exposure monitoring has been performed with either {sup 32}P-postlabeling or immunoassays, neither of which is able to chemically characterize specific DNA adducts. Recently developed combinations of methods with chemical and physical end points have allowed identification of specific adducts in human tissues. Studies are presented that demonstrate that high ambient levels of benzo[a]pyrene are associated with high levels of DNA adducts in human blood cell DNA and that the same DNA adduct levels drop when the ambient PAH levels decrease significantly. DNA adduct dosimetry, which has been achieved with some dietary carcinogens and cancer chemotherapeutic agents, is described, as well as studies correlating DNA adducts with other biomarkers. It is likely that some toxic, noncarcinogenic compounds may have genotoxic effects, including oxidative damage, and that adverse health outcomes other than cancer may be correlated with DNA adduct formation. The studies presented here may serve as useful prototypes for exploration of other toxicological end points. 156 refs., 1 fig., 3 tabs.

  20. Thermochromic organometallic complexes: experimental and theoretical studies of 16- to 18-electron interconversions of adducts of arene Ru(II) carboranes with aromatic amine ligands.

    PubMed

    Barry, Nicolas P E; Deeth, Robert J; Clarkson, Guy J; Prokes, Ivan; Sadler, Peter J

    2013-02-21

    A series of 18-electron complexes of general formula [Ru(p-cym)(1,2-dicarba-closo-dodecaborane-1,2-dithiolato)(L)] (p-cym = para-cymene; L = 4-dimethylaminopyridine (2), nicotinamide (3), 3-ethynylpyridine (4), N-methylimidazole (5), 4-cyanopyridine (6), and pyridine (7)) were synthesised by reactions between the 16-electron precursor [Ru(p-cym)(1,2-dicarba-closo-dodecaborane-1,2-dithiolato)] (1) and corresponding heterocyclic bases. X-ray crystal structures of complexes 2 and 5 were determined. In dichloromethane and chloroform solutions at ambient temperature, the 18-electron complexes 2-7 are in equilibrium with the 16-electron precursor 1. Each equilibrium is displaced towards the formation of the blue 16-electron or yellow 18-electron complex by increasing or decreasing the temperature of the solution, respectively, which results in controlled and reversible thermochromism. Binding constants (K) and Gibbs free energies (ΔG°) of the six equilibria have been determined by a combination of experiments (Job plots, UV-visible titrations, NMR studies) and also by computation (time-dependent density functional theory, TD-DFT). A linear free energy relationship for log K versus pK(a) for the pyridine and imidazole ligands was established. The predicted strong interactions of 1 with other aromatic amine ligands, such as amphetamine derivatives, were verified experimentally. This appears to be the first report of reversible 16/18-electron interconversions with associated thermochromic properties for a well-known family of complexes.

  1. Evaluation of 8-hydroxy-2'-deoxyguanosine (8-OHdG) adduct levels and DNA strand breaks in human peripheral blood lymphocytes exposed in vitro to polycyclic aromatic hydrocarbons with or without animal metabolic activation.

    PubMed

    Isabel, Rodríguez-Romero María; Sandra, Gómez-Arroyo; Rafael, Villalobos-Pietrini; Carmen, Martínez-Valenzuela; Josefina, Cortés-Eslava; del Carmen, Calderón-Ezquerro María; Rocío, García-Martínez; Francisco, Arenas-Huertero; Elena, Calderón-Segura María

    2012-04-01

    The polycyclic aromatic hydrocarbons (PAHs) dibenzo(a,h)anthracene, benzo(ghi)perylene, benzo(b)fluoranthene and benzo(a)pyrene have been identified in urban air from Mexico City and some of them are classified as human carcinogens. In the present study, human peripheral blood lymphocytes were exposed in vitro to different concentrations of PAHs with (+S9) or without (-S9) metabolic activation. The genotoxic and cytotoxic effects of each PAH were examined with an alkaline comet assay and trypan blue dye exclusion, and oxidative DNA damage was determined via the detection of 8-hydroxy-2'-deoxyguanosine (8-OhdG) adduct levels by enzyme-linked immunosorbent assay (ELISA). The DNA damage was evaluated with two genotoxicity parameters: the frequency of comets and the comet tail length. Concentrations of 20, 40, 80, 160 and 320 µM DB(a,h)A-S9; 20, 40, 80, 160 and 240 µM B(ghi)P-S9; 20, 30, 40, 60 and 80 µM B(b)F-S9; and 80 µM B(a)P-S9 for 24 h induced a small but significant increase in the means of comet frequency, in the tail length and in the 8-oHDg levels in relation to the control (0.5% DMSO-S9). However, all PAHs+S9 produced a more significant increase in DNA strand breaks and the level of 8-OHdG compared with the control (0.5% DMSO+S9), with a concentration-effect relationship. The viability of lymphocytes exposed to all PAHs-S9 and PAHs+S9 was not modified compared with the control. The results of this study demonstrate that the comet and ELISA are rapid, suitable and sensitive methods to detect in vitro PAH-induced DNA damage in human peripheral lymphocytes.

  2. Prenatal Exposure to Polycyclic Aromatic Hydrocarbons /Aromatics, BDNF and Child Development

    PubMed Central

    Perera, Frederica; Phillips, David H.; Wang, Ya; Roen, Emily; Herbstman, Julie; Rauh, Virginia; Wang, Shuang; Tang, Deliang

    2015-01-01

    Objectives Within a New York City (NYC) birth cohort, we assessed the associations between polycyclic aromatic hydrocarbon (PAH) and other aromatic DNA adducts and brain derived neurotrophic factor (BDNF) concentrations in umbilical cord blood, and neurodevelopment at age 2 years and whether BDNF is a mediator of the associations between PAH/aromatic-DNA adducts and neurodevelopment. Methods PAH/aromatic-DNA adduct concentrations in cord blood were measured in 505 children born to nonsmoking African-American and Dominican women residing in NYC, and a subset was assessed for neurodevelopment at 2 years using the Bayley Scales of Infant Development Mental Development Index (MDI). A spectrum of PAH/aromatic-DNA adducts was measured using the 32P-postlabeling assay; DNA adducts formed by benzo[a]pyrene (B[a]P), a representative PAH, were measured by High Performance Liquid Chromatography (HPLC)/fluorescence. BDNF mature protein in cord blood plasma was quantified by an ELISA. Multivariate regression analysis, adjusting for potential confounders, was conducted. Results PAH/aromatic-DNA adduct concentration measured by postlabeling was inversely associated with BDNF concentration (p=0.02) and with MDI scores at 2 years (p=0.04). BDNF level was positively associated with MDI scores (p=0.003). Restricting to subjects having all three measures (PAH/aromatic-DNA adducts by postlabeling, MDI, and BDNF), results were similar but attenuated (p=0.13, p=0.05, p=0.01, respectively). Associations between B[a]P-DNA adducts and BDNF and B[a]P-DNA adducts and MDI at age 2 years were not significant. At age 3 years, the positive association of BDNF with MDI was not observed. Conclusions The results at age 2 suggest that prenatal exposure to a spectrum of PAH/aromatic pollutants may adversely affect early neurodevelopment, in part by reducing BDNF levels during the fetal period. However, the same relationship was not seen at age 3. PMID:26301740

  3. DNA adducts in hematopoietic tissues and blood of the mummichog (Fundulus heteroclitus) from a creosote-contaminated site in the Elizabeth River, Virginia.

    PubMed

    Rose, W L; French, B L; Reichert, W L; Faisal, M

    2000-01-01

    Hydrophobic DNA adducts were examined in liver, anterior kidney, spleen, and blood of tumor-prone mummichog (Fundulus heterclitus) from the creosote-contaminated Atlantic Wood (AW) site (Elizabeth River, Virginia). DNA adducts eluted in a diagonal radioactive zone, characteristic of polycyclic aromatic hydrocarbon exposure, in all examined tissues of AW fish. Mummichog demonstrated significantly higher levels of DNA adducts in spleen (394 +/- 109 nmol adducts/mol nucleotides) than in liver (201 +/- 77 nmol adducts/mol nucleotides) or anterior kidney (211 +/- 68 nmol adducts/mol nucleotides; P = 0.036). The levels of DNA adducts in the pooled blood (pool of four) were 142 nmol adducts/mol nucleotides. DNA adducts were not detected in the liver, anterior kidney, spleen and blood of fish collected from the reference site (< 2 nmol adducts/mol nucleotides). The high levels of DNA adducts detected in tissues of AW mummichog may be linked to the increased cancer incidence and immunosuppression in this population.

  4. Sperm DNA oxidative damage and DNA adducts

    PubMed Central

    Jeng, Hueiwang Anna; Pan, Chih-Hong; Chao, Mu-Rong; Lin, Wen-Yi

    2015-01-01

    The objective of this study was to investigate DNA damage and adducts in sperm from coke oven workers who have been exposed to polycyclic aromatic hydrocarbons. A longitudinal study was conducted with repeated measurements during spermatogenesis. Coke-oven workers (n=112) from a coke-oven plant served the PAH-exposed group, while administrators and security personnel (n=67) served the control. Routine semen parameters (concentration, motility, vitality, and morphology) were analyzed simultaneously; the assessment of sperm DNA integrity endpoints included DNA fragmentation, bulky DNA adducts, and 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxo-dGuo). The degree of sperm DNA fragmentation was measured using the terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) assay and sperm chromatin structure assay (SCSA). The PAH-exposed group had a significant increase in bulky DNA adducts and 8-oxo-dGuo compared to the control subjects (Ps = 0.002 and 0.045, respectively). Coke oven workers' percentages of DNA fragmentation and denaturation from the PAH-exposed group were not significantly different from those of the control subjects (Ps = 0.232 and 0.245, respectively). Routine semen parameters and DNA integrity endpoints were not correlated. Concentrations of 8-oxo-dGuo were positively correlated with percentages of DNA fragmentation measured by both TUNEL and SCSA (Ps = 0.045 and 0.034, respectively). However, the concentrations of 8-oxo-dGuo and percentages of DNA fragmentation did not correlate with concentrations of bulky DNA adducts. In summary, coke oven workers with chronic exposure to PAHs experienced decreased sperm DNA integrity. Oxidative stress could contribute to the degree of DNA fragmentation. Bulky DNA adducts may be independent of the formation of DNA fragmentation and oxidative adducts in sperm. Monitoring sperm DNA integrity is recommended as a part of the process of assessing the impact of occupational and environmental toxins on

  5. Solution structure and 5{prime}-intercalation of the polynuclear aromatic BP residue in a (+)-cis-anti-[BP]-N{sup 6}-dA adduct opposite dT in a DNA duplex

    SciTech Connect

    Mao, B.; Patel, D.J.; Chen, J.; Geacintov, N.E.; Broyde, S.

    1996-12-31

    The covalent binding of anti-benzo[a]pyrene-7,8-dihydroxy-9,10-epoxide (BPDE) to cellular DNA gives rise predominantly to WAG and N6-dA adducts. While the latter are formed in minor proportions, the mutagenic potential of these BPDE-N6-dA lesions could be important and dependent on the adduct structure. We have applied a combined NMR-molecular mechanics approach to determine the solution conformation of the minor (+)-cis-anti-[BP]dA adduct positioned opposite dT in the duplex d(C1-T2-C3-T4-C5-[BP-A6]-C7-T8-T9-C10- C11).d(G22-A21-G20-A19-G18-T17-G16-A15-A14-G14-G13-G12). The BP ring system is intercalated to the 5{prime}-side of the [BP]dA6 lesion site without disrupting the flanking Watson-Crick dC5.dG18 and [BP]dA6.dT17 base pairs. This is achieved in part by a buckling and propeller-twisting of the Watson-Crick [BP]dA6.dT17 base pair, as observed in the (+)-trans-anti-[BcPh-dA6.dT17] adduct (BcPh=benzo[c]phenanthrenyl) in the same sequence context, and which is stereochemically similar at the linkage site.

  6. POOLED ANALYSIS OF STUDIES ON DNA ADDUCTS AND DIETARY VITAMINS

    PubMed Central

    Ragin, Camille; Minor, Aerie; Agudo, Antonio; Farmer, Peter; Garte, Seymour; Gonzales, Carlos; Kalina, Ivan; Matullo, Pino; Popov, Todor; Palli, Domenico; Peluso, Marco; Riccieri, Fulvio; Sram, Radim; Vineis, Paolo; Taioli, Emanuela

    2010-01-01

    Objectives There is some evidence that dietary components that are rich in antioxidant and vitamins are inversely associated with DNA adduct levels induced by environmental carcinogens such as polycyclic aromatic hydrocarbons, although the epidemiologic data are inconsistent. This study addresses the association between vitamins, DNA adducts and smoking. Methods A combined analysis of individual data on the association between bulky DNA adducts and dietary vitamins were conducted. A Medline search was performed to identify studies on healthy subjects in which smoking and vitamins intake information were available, and bulky DNA adducts were measured in peripheral blood with 32P post labeling. Eight published studies met the eligibility criteria, and individual data from 7 data sets including 2,758 subjects were obtained. GSTM1 and GSTT1 were also available on all the subjects. Results Vitamin E was inversely significantly associated with DNA adducts after adjustment for possible confounding factors. Vitamin A and C were not independent predictors of DNA adducts. A stratified analysis showed that vitamin A had a significant inverse association with DNA adducts in ever smokers only. Conclusions This result is relevant to planning any future chemo-preventive interventions directed to high risk subgroups of the population, for cancer prevention. PMID:20399891

  7. Influence of Na+ on DNA reactions with aromatic epoxides and diol epoxides: evidence that DNA catalyzes the formation of benzo[a]pyrene and benz[a]anthracene adducts at intercalation sites.

    PubMed

    Fernando, H; Huang, C R; Milliman, A; Shu, L; LeBreton, P R

    1996-12-01

    Reactions of the benzo[a]pyrene (BP) and benz[a]anthracene (BA) metabolites, (+/-)-trans-7 8-dihydroxy-anti-9, 10-epoxy-7, 8, 9, 10-tetrahydro-BP (BPDE), (+/-)-trans-3, 4-dihydroxy-anti- 1,2-epoxy-1,2,3,4-tetrahydro-BA (BADE), (+/-)-BP-4,5-oxide (BPO), and (+/-)-BA-5, 6-oxide (BAO), were examined under pseudo-first-order conditions at varying Na+ (2.0-100 Mm) and native calf thymus DNA (ctDNA) concentrations. In 0.2 mM ctDNA and 2.0 mM Na+, at a pH of 7.3 most BPDE, BADE, BPO, and BAO (87-95%) undergo DNA catalyzed hydrolysis or rearrangement. For BPDE and BPO, overall, pseudo-first-order rate constants, k, in 2.0 mM Na+ and 0.2 mM ctDNA are 21-72 times larger than values obtained without DNA. For BADE and BAO, the rate constants are less strongly influenced by DNA; k values in 0.2 mM ctDNA are only 9-12 times larger than values obtained without DNA. Kinetic data for BPDE, BPO, BADE, and BAO and DNA intercalation association constants (KA) for BP and BA diols which are model compounds indicate that KA values for BPDE and BPO in 2.0 mM Na+ are 6.6-59 times larger than those of BADE and BAO. The greater DNA enhancement of rate constants for BPDE and BPO, versus BADE and BAO, correlates with the larger KA values of the BP metabolites. DNA adducts, which account for less than 10% of the yields, also form. For BPDE in 0.20 mM ctDNA, k decreases 5.1 times as the Na+ concentration increases from 2.0 to 100 mM. Nevertheless, the DNA adduct level remains constant over the range of Na+ concentrations examined. These results provide evidence that, for BPDE in 0.20 mM DNA and 2.0 mM Na+, ctDNA adduct formation follows a mechanism which is similar to that for DNA catalyzed hydrolysis. The pseudo-first-order rate constant for adduct formation, kAd, given approximately by kAd approximately equal to (kcat,AdKA[DNA])/(1 + KA[DNA]), where kcat,Ad is a catalytic rate constant. for BADE, BPO, and BAO, the influence of varying DNA and Na+ concentrations on k values is similar to that

  8. Low response in white blood cell DNA adducts among workers in a highly polluted cokery environment.

    PubMed

    Kuljukka, T; Savela, K; Vaaranrinta, R; Mutanen, P; Veidebaum, T; Sorsa, M; Peltonen, K

    1998-06-01

    Coke oven workers are often heavily exposed to polynuclear aromatic hydrocarbons (PAHs); this exposure has been associated with higher cancer rates among these workers. We assessed the exposure of cokery workers in an oil shale processing plant. Personal hygienic monitoring, measurement of urinary 1-hydroxypyrene (1-OHP), and analysis of PAH-DNA adducts in white blood cells (WBCs) were performed. The 32P-postlabeling method was used for adduct measurement. The mean adduct value, 1.6 adducts per 10(8) nucleotides, did not differ significantly from the control value (P = 0.098). Smokers had significantly higher adduct levels than non-smoking workers (P = 0.002). 1-OHP levels measured in post-shift samples correlated with DNA adducts found in white blood cells (WBCs). We conclude that hygienic monitoring and measurement of urinary metabolites are essential background exposure data when the biologically effective dose of chemical carcinogens is assessed.

  9. Cytochrome P450 1b1 in polycyclic aromatic hydrocarbon (PAH)-induced skin carcinogenesis: Tumorigenicity of individual PAHs and coal-tar extract, DNA adduction and expression of select genes in the Cyp1b1 knockout mouse

    SciTech Connect

    Siddens, Lisbeth K.; Bunde, Kristi L.; Harper, Tod A.; McQuistan, Tammie J.; Löhr, Christiane V.; Bramer, Lisa M.; Waters, Katrina M.; Tilton, Susan C.; Krueger, Sharon K.; and others

    2015-09-01

    FVB/N mice wild-type, heterozygous or null for Cyp 1b1 were used in a two-stage skin tumor study comparing PAH, benzo[a]pyrene (BaP), dibenzo[def,p]chrysene (DBC), and coal tar extract (CTE, SRM 1597a). Following 20 weeks of promotion with TPA the Cyp 1b1 null mice, initiated with DBC, exhibited reductions in incidence, multiplicity, and progression. None of these effects were observed with BaP or CTE. The mechanism of Cyp 1b1-dependent alteration of DBC skin carcinogenesis was further investigated by determining expression of select genes in skin from DBC-treated mice 2, 4 and 8 h post-initiation. A significant reduction in levels of Cyp 1a1, Nqo1 at 8 h and Akr 1c14 mRNA was observed in Cyp 1b1 null (but not wt or het) mice, whereas no impact was observed in Gst a1, Nqo 1 at 2 and 4 h or Akr 1c19 at any time point. Cyp 1b1 mRNA was not elevated by DBC. The major covalent DNA adducts, dibenzo[def,p]chrysene-(±)-11,12-dihydrodiol-cis and trans-13,14-epoxide-deoxyadenosine (DBCDE-dA) were quantified by UHPLC-MS/MS 8 h post-initiation. Loss of Cyp1 b1 expression reduced DBCDE-dA adducts in the skin but not to a statistically significant degree. The ratio of cis- to trans-DBCDE-dA adducts was higher in the skin than other target tissues such as the spleen, lung and liver (oral dosing). These results document that Cyp 1b1 plays a significant role in bioactivation and carcinogenesis of DBC in a two-stage mouse skin tumor model and that loss of Cyp 1b1 has little impact on tumor response with BaP or CTE as initiators. - Highlights: • Cyp1b1 null mice exhibit lower skin cancer sensitivity to DBC but not BaP or CTE. • Cyp1b1 expression impacts expression of other PAH metabolizing enzymes. • cis/trans-DBCDE-dA ratio significantly higher in the skin than the spleen, lung or liver • Potency of DBC and CTE in mouse skin is higher than predicted by RPFs.

  10. Formation of DNA adducts from oil-derived products analyzed by 32P-HPLC.

    PubMed

    Akkineni, L K; Zeisig, M; Baranczewski, P; Ekström, L G; Möller, L

    2001-01-01

    The aim of this study was to investigate the genotoxic potential of DNA adducts and to compare DNA adduct levels and patterns in petroleum vacuum distillates, coal tar distillate, bitumen fume condensates, and related substances that have a wide range of boiling temperatures. An in vitro assay was used for DNA adduct analysis with human and rat S-9 liver extract metabolic activation followed by 32P-postlabeling and 32P-high-performance liquid chromatography (32p-HPLC). For petroleum distillates originating from one crude oil there was a correlation between in vitro DNA adduct formation and mutagenic index, which showed an increase with a distillation temperature of 250 degrees C and a peak around a distillation point of approximately 400 degrees C. At higher temperatures, the genotoxicity (DNA adducts and mutagenicity) rapidly declined to very low levels. Different petroleum products showed a more than 100-fold range in DNA adduct formation, with severely hydrotreated base oil and bitumen fume condensates being lowest. Coal tar distillates showed ten times higher levels of DNA adduct formation than the most potent petroleum distillate. A clustered DNA adduct pattern was seen over a wide distillation range after metabolic activation with liver extracts of rat or human origin. These clusters were eluted in a region where alkylated aromatic hydrocarbons could be expected. The DNA adduct patterns were similar for base oil and bitumen fume condensates, whereas coal tar distillates had a wider retention time range of the DNA adducts formed. Reference substances were tested in the same in vitro assay. Two- and three-ringed nonalkylated aromatics were rather low in genotoxicity, but some of the three- to four-ringed alkylated aromatics were very potent inducers of DNA adducts. Compounds with an amino functional group showed a 270-fold higher level of DNA adduct formation than the same structures with a nitro functional group. The most potent DNA adduct inducers of the 16

  11. 32P-postlabeling DNA adduct assay: cigarette smoke-induced dna adducts in the respiratory and nonrespiratory rat tissues. Book chapter

    SciTech Connect

    Gupta, R.C.; Gairola, C.G.

    1990-01-01

    An analysis of the tissue DNA adducts in rats by the sensitive (32)p-postlabeling assay showed one to eight detectable DNA adducts in lung, trachea, larynx, heart and bladder of the sham controls. Chronic exposure of animals to mainstream cigarette smoke showed a remarkable enhancement of most adducts in the lung and heart DNA. Since cigarette smoke contains several thousand chemicals and a few dozen of them are known or potential carcinogens, the difference between the DNA adducts of nasal and the other tissues may reflect the diversity of reactive constituents and their differential absorption in different tissues. In comparison to the lung DNA adducts, the adducts in nasal DNA were less hydrophobic. Identity of the predominant adducts was further investigated by comparison with several reference DNA adducts from 10 PAH and aromatic amines. Since some of these chemicals are present in cigarette smoke, the results suggest that these constituents of cigarette smoke may not be directly responsible for formation of DNA adducts in the lung and heart of the smoke-exposed animals.

  12. Detection of benzo[a]pyrene diol epoxide-DNA adducts in peripheral blood lymphocytes and antibodies to the adducts in serum from coke oven workers.

    PubMed Central

    Harris, C C; Vahakangas, K; Newman, M J; Trivers, G E; Shamsuddin, A; Sinopoli, N; Mann, D L; Wright, W E

    1985-01-01

    Coke oven workers are exposed to high levels of carcinogenic polycyclic aromatic hydrocarbons, including benzo[a]pyrene (B[a]P), and are at increased risk of lung cancer. Since B[a]P is enzymatically activated to 7 beta,8 alpha-dihydroxy(9 alpha, 10 alpha)epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene (B[a]PDE) that forms adducts with DNA, the presence of these adducts was measured in DNA from peripheral blood lymphocytes by synchronous fluorescence spectrophotometry and enzyme radioimmunoassay. Approximately two-thirds of the workers had detectable levels of B[a]PDE-DNA adducts. Antibodies to the DNA adducts were also found in the serum of 27% of the workers. B[a]PDE-DNA adducts were not detectable in lymphocytes and antibodies to the adducts were not detected in sera from a control group of nonsmoking laboratory workers. DNA adducts and/or antibodies to the adducts indicate exposure to B[a]P and its metabolic activation to the carcinogenic metabolite that covalently binds to and damages DNA. Detection of adducts and antibodies to them may also be useful as internal dosimeters of the pathobiological effective doses of chemical carcinogens. PMID:2413443

  13. Significance of DNA adduct studies in animal models for cancer molecular dosimetry and risk assessment.

    PubMed Central

    Beland, F A; Poirier, M C

    1993-01-01

    To elucidate the relationship between DNA adduct formation and tumorigenesis, a number of experiments have been conducted to measure DNA adducts in target tissues from experimental animals during continuous exposure to carcinogens. With aflatoxins, aromatic amines, and polycyclic aromatic hydrocarbons, tumor induction appears to be associated with the major DNA adduct detected, whereas with N-nitrosamines the response is normally correlated with minor forms of DNA damage. During continuous carcinogen administration, steady-state adduct concentrations are generally obtained in the target tissues, and there is often a linear correlation between the carcinogen concentration and the steady-state DNA adduct level. Exceptions exist when the mechanism of activation changes or with the onset of significant toxicity. Steady-state DNA adduct levels are often linearly related to the tumorigenic response. Carcinogen-induced cell proliferation occurs when significant deviations from linearity are observed. Because DNA adducts detected in humans are chemically identical to those found in experimental animals, DNA adduct data in animals may contribute to our understanding of human cancer risk. PMID:8319658

  14. ACCUMULATION OF M1DG DNA ADDUCTS AFTER ...

    EPA Pesticide Factsheets

    ABSTRACT: Oxidative DNA damage is one of the key events leading to mutation and cancer. The present study examined the accumulation of M1dG DNA adducts, 3-(2’-deoxy-β-D-erythro-pentofuranosyl)-pyrimido[1,2-a]-purin-10(3H)-one, after single or yearly exposure to polyhalogenated aromatic hydrocarbons (PHAH) in order to test the role of oxidative DNA damage in PHAH carcinogenicity. The effect of PHAH exposure on the number of M1dG adducts was explored initially in female mice exposed to a single dose of either TCDD or a PHAH mixture. This study demonstrated that a single exposure to PHAH had no significant effect on the number of M1dG adducts compared to the corn oil control group. The role of M1dG adducts in PCB-induced carcinogenicity was further investigated in rats exposed for a year to PCB 153, PCB 126, or a mixture of the two. PCB 153 had no significant effect on M1dG adducts number in liver and brain tissues from the exposed rats compared to controls. However, high dose PCB 126 exposure resulted in M1dG adducts accumulation in the liver. More importantly, starting at low doses, co-administration of equal proportions of PCB 153 and PCB 126 resulted in dose-dependent increases in M1dG adducts accumulation in the liver. Interestingly, the result from co-administration of different amounts of PCB 153 with fixed amounts of PCB 126 demonstrated more M1dG adducts accumulation with higher doses of PCB 153. These results are consistent with the results from canc

  15. Correlation of mutagenic potencies of various petroleum oils and oil coal tar mixtures with DNA adduct levels in vitro.

    PubMed

    Reddy, M V; Blackburn, G R; Schreiner, C A; Mackerer, C R

    1997-08-01

    An in vitro system was utilized to measure DNA adduct-forming ability of petroleum oils and oil coal tar mixtures to define correlations between DNA adduct levels and their mutagenic potencies. The system consisted of reaction of dimethyl sulfoxide extracts of oils with calf thymus DNA in the presence of Aroclor-induced hamster liver microsomes for 30 min. Following DNA extraction, DNA adducts were measured by the nuclease P1-enhanced postlabeling assay coupled with two-dimensional polyethyleneimine (PEI)-cellulose TLC. Thin layer plates showed putative aromatic DNA adducts, with levels ranging from 60 to 1400 adducts per 10(9) DNA nucleotides. TLC mobilities suggested adducts to be aromatic compounds containing 4 or more rings. A good correlation (coefficient of correlation = 0.91) was observed between DNA adduct levels and Salmonella mutagenicity for 19 oils. All 19 samples tested produced DNA adducts. To expedite the TLC procedure, adducts were resolved by one-dimensional TLC and the radioactivity measured using a mechanical scanner. Results were comparable to those obtained by two-dimensional TLC and quantification after scraping. Our data show that the in vitro incubation system coupled with the postlabeling adduct assay is a useful screening method to identify mutagenic and potentially carcinogenic oils.

  16. An efficient carbonyl-alkene metathesis of bicyclic oxetanes: photoinduced electron transfer reduction of the Paternò-Büchi adducts from 2,3-dihydrofuran and aromatic aldehydes.

    PubMed

    Pérez-Ruiz, Raúl; Miranda, Miguel A; Alle, Ronald; Meerholz, Klaus; Griesbeck, Axel G

    2006-01-01

    The bicyclic oxetanes and resulting from photocycloaddition of aromatic aldehydes to 2,3-dihydrofuran, were efficiently cleaved by means of electron-transfer reduction, photoinduced by the electronically excited reductants 1-methoxynaphthalene (MN) and 2,7-dimethoxynaphthalene (DMN) in acetonitrile. The fluorescence quenching rates of DMN/MN by and were determined by static methods, the triplet quenching rates were determined by means of laser flash photolysis (LFP). The product analysis established a "photo-photo metathesis" where both cycloaddition and cycloreversion processes are induced by photochemical processes.

  17. Effect of phytochemical intervention on dibenzo[a,l]pyrene-induced DNA adduct formation

    PubMed Central

    Russell, Gilandra K.; Gupta, Ramesh C.; Vadhanam, Manicka V.

    2015-01-01

    Dibenzo[a,l]pyrene (DBP) has been found to be the most potent carcinogen of the polycyclic aromatic hydrocarbons (PAHs). Primary sources for DBP in the environment are combustion of wood and coal burning, gasoline and diesel exhaust, and tires. Given the likelihood of environmental exposure to DBP and strong experimental evidence of its potency, it is likely to contribute to lung cancer development. Intervention with compounds of natural origin (“phytochemicals”) is considered an effective means to prevent cancer development and favorably modulate the underlying mechanisms, including DNA adduct formation. In this study, several agents have been identified that inhibit environmental carcinogen-induced DNA adduct formation using a cell-free microsomal system. Of the ten agents tested, resveratrol (648 ± 26 adducts/109 nucleotides), oltipraz (1007 ± 348 adducts/109 nucleotides), delphinidin (1252 ± 142 adducts/109 nucleotides), tanshinone I (1981 ± 213 adducts/109 nucleotides), tanshinone IIA (2606 ± 478 adducts/109 nucleotides) and diindoylmethane (3643 ± 469 adducts/109 nucleotides) were the most effective compared to vehicle treatment (14,062 ± 1097 adducts/109 nucleotides). DBP is metabolized by phase I metabolizing enzymes CYP1A1, CYP1A2, and CYP1B1. DBP-induced DNA adducts can be inhibited by several mechanisms. We found that all the test agents inhibited DNA adducts by inhibiting one or more of these enzymes. Oltipraz inhibited DNA adducts entirely by inhibiting the CYP450s, while resveratrol and delphinidin inhibited DNA adducts by also interacting directly with the carcinogenic metabolite, anti-dibenzo(a,l)pyrene-11,12-dihydrodiol-13,14-epoxide. PMID:25794985

  18. Effect of phytochemical intervention on dibenzo[a,l]pyrene-induced DNA adduct formation.

    PubMed

    Russell, Gilandra K; Gupta, Ramesh C; Vadhanam, Manicka V

    2015-04-01

    Dibenzo[a,l]pyrene (DBP) has been found to be the most potent carcinogen of the polycyclic aromatic hydrocarbons (PAHs). Primary sources for DBP in the environment are combustion of wood and coal burning, gasoline and diesel exhaust, and tires. Given the likelihood of environmental exposure to DBP and strong experimental evidence of its potency, it is likely to contribute to lung cancer development. Intervention with compounds of natural origin ("phytochemicals") is considered an effective means to prevent cancer development and favorably modulate the underlying mechanisms, including DNA adduct formation. In this study, several agents have been identified that inhibit environmental carcinogen-induced DNA adduct formation using a cell-free microsomal system. Of the ten agents tested, resveratrol (648 ± 26 adducts/10(9) nucleotides), oltipraz (1007 ± 348 adducts/10(9) nucleotides), delphinidin (1252 ± 142 adducts/10(9) nucleotides), tanshinone I (1981 ± 213 adducts/10(9) nucleotides), tanshinone IIA (2606 ± 478 adducts/10(9) nucleotides) and diindoylmethane (3643 ± 469 adducts/10(9) nucleotides) were the most effective compared to vehicle treatment (14,062 ± 1097 adducts/10(9) nucleotides). DBP is metabolized by phase I metabolizing enzymes CYP1A1, CYP1A2, and CYP1B1. DBP-induced DNA adducts can be inhibited by several mechanisms. We found that all the test agents inhibited DNA adducts by inhibiting one or more of these enzymes. Oltipraz inhibited DNA adducts entirely by inhibiting the CYP450s, while resveratrol and delphinidin inhibited DNA adducts by also interacting directly with the carcinogenic metabolite, anti-dibenzo(a,l)pyrene-11,12-dihydrodiol-13,14-epoxide. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Bulky DNA adducts in white blood cells: a pooled analysis of 3600 subjects

    PubMed Central

    Ricceri, Fulvio; Godschalk, Roger; Peluso, Marco; Phillips, David H.; Agudo, Antonio; Georgiadis, Panos; Loft, Steffen; Tjonneland, Anne; Raaschou-Nielsen, Ole; Palli, Domenico; Perera, Frederica; Vermeulen, Roel; Taioli, Emanuela; Sram, Radim J.; Munnia, Armelle; Rosa, Fabio; Allione, Alessandra; Matullo, Giuseppe; Vineis, Paolo

    2013-01-01

    Background Bulky DNA adducts are markers of exposure to genotoxic aromatic compounds, which reflect an individual’s ability to metabolically activate carcinogens and to repair DNA damage. Polycyclic aromatic hydrocarbons (PAH) represent a major class of carcinogens that are capable of forming such adducts. Factors that have been reported to be related to DNA adduct levels include smoking, diet, body mass index (BMI), genetic polymorphisms, the season of collection of biologic material, and air pollutants. Methods We pooled eleven studies (3,600 subjects) in which bulky DNA adducts were measured in human white blood cells with similar 32P-postlabelling techniques and for which a similar set of variables was available, including individual data on age, gender, ethnicity, batch, smoking habits, BMI, season of blood collection and a limited set of gene variants. Results Lowest DNA adduct levels were observed in the spring (median 0.50 adducts per 108 nucleotides), followed by summer (0.64), autumn (0.70) and winter (0.85) (p=0.006). The same pattern emerged in multivariate analysis, but only among never smokers (p=0.02). Adduct levels were significantly lower (p=0.001) in Northern Europe (the Netherlands, Denmark) (mean 0.60, median 0.40) than in Southern Europe (Italy, Spain, France, Greece) (mean 0.79, median 0.60). Conclusions In this large pooled analysis, we have found only weak associations between bulky DNA adducts and exposure variables. Seasonality (with higher adducts levels in winter) and air pollution may partly explain some of the inter-area differences (North vs South Europe), but most inter-area and inter-individual variation in adduct levels still remain unexplained. Impact Our study describes the largest pooled analysis of bulky DNA adducts so far, showing that inter-individual variation is still largely unexplained, though seasonality appears to play a role. PMID:20921335

  20. Isolevuglandin Adducts in Disease

    PubMed Central

    Bi, Wenzhao

    2015-01-01

    Abstract Significance: A diverse family of lipid-derived levulinaldehydes, isolevuglandins (isoLGs), is produced by rearrangement of endoperoxide intermediates generated through both cyclooxygenase (COX) and free radical-induced cyclooxygenation of polyunsaturated fatty acids and their phospholipid esters. The formation and reactions of isoLGs with other biomolecules has been linked to alcoholic liver disease, Alzheimer's disease, age-related macular degeneration, atherosclerosis, cardiac arythmias, cancer, end-stage renal disease, glaucoma, inflammation of allergies and infection, mitochondrial dysfunction, multiple sclerosis, and thrombosis. This review chronicles progress in understanding the chemistry of isoLGs, detecting their production in vivo and understanding their biological consequences. Critical Issues: IsoLGs have never been isolated from biological sources, because they form adducts with primary amino groups of other biomolecules within seconds. Chemical synthesis enabled investigation of isoLG chemistry and detection of isoLG adducts present in vivo. Recent Advances: The first peptide mapping and sequencing of an isoLG-modified protein present in human retina identified the modification of a specific lysyl residue of the sterol C27-hydroxylase Cyp27A1. This residue is preferentially modified by iso[4]LGE2 in vitro, causing loss of function. Adduction of less than one equivalent of isoLG can induce COX-associated oligomerization of the amyloid peptide Aβ1-42. Adduction of isoLGE2 to phosphatidylethanolamines causes gain of function, converting them into proinflammatory isoLGE2-PE agonists that foster monocyte adhesion to endothelial cells. Future Directions: Among the remaining questions on the biochemistry of isoLGs are the dependence of biological activity on isoLG isomer structure, the structures and mechanism of isoLG-derived protein–protein and DNA–protein cross-link formation, and its biological consequences. Antioxid. Redox Signal. 22

  1. Formation of metal-ion adducts and evidence for surface-catalyzed ionization in electrospray analysis of pharmaceuticals and pesticides

    USGS Publications Warehouse

    Thurman, E.M.; Ferrer, I.

    2002-01-01

    The formation of metal ion adducts in liquid chromatography/mass spectrometry positive-ion electrospray analysis of pharmaceuticals and pesticides was investigated. The evidence of surface-catalyzed ionization in the electrospray analysis was also studied. Both positive and negative ion mass spectrometry were used for the analysis of the products. It was found that the sodium adducts formed in the analysis included single, double, and triple sodium adducts. Adduction was found to occur by attachment of the metal ion to carboxyl, carbonyl and aromatic pi electrons of the molecule.

  2. Formation and persistence of arylamine DNA adducts in vivo.

    PubMed Central

    Beland, F A; Kadlubar, F F

    1985-01-01

    Aromatic amines are urinary bladder carcinogens in man and induce tumors at a number of sites in experimental animals including the liver, mammary gland, intestine, and bladder. In this review, the particular pathways involved in the metabolic activation of aromatic amines are considered as well as the specific DNA adducts formed in target and nontarget tissue. Particular emphasis is placed on the following compounds: 1-naphthylamine, 2-naphthylamine, 4-aminobiphenyl, 4-acetylaminobiphenyl, 4-acetylamino-4'-fluorobiphenyl, 3,2'-dimethyl-4-aminobiphenyl, 2-acetylaminofluorene, benzidine, N-methyl-4-aminoazobenzene, 4-aminoazobenzene, and 2-acetylaminophenanthrene. PMID:4085422

  3. Alcohol, Aldehydes, Adducts and Airways

    PubMed Central

    Sapkota, Muna; Wyatt, Todd A.

    2015-01-01

    Drinking alcohol and smoking cigarettes results in the formation of reactive aldehydes in the lung, which are capable of forming adducts with several proteins and DNA. Acetaldehyde and malondialdehyde are the major aldehydes generated in high levels in the lung of subjects with alcohol use disorder who smoke cigarettes. In addition to the above aldehydes, several other aldehydes like 4-hydroxynonenal, formaldehyde and acrolein are also detected in the lung due to exposure to toxic gases, vapors and chemicals. These aldehydes react with nucleophilic targets in cells such as DNA, lipids and proteins to form both stable and unstable adducts. This adduction may disturb cellular functions as well as damage proteins, nucleic acids and lipids. Among several adducts formed in the lung, malondialdehyde DNA (MDA-DNA) adduct and hybrid malondialdehyde-acetaldehyde (MAA) protein adducts have been shown to initiate several pathological conditions in the lung. MDA-DNA adducts are pre-mutagenic in mammalian cells and induce frame shift and base-pair substitution mutations, whereas MAA protein adducts have been shown to induce inflammation and inhibit wound healing. This review provides an insight into different reactive aldehyde adducts and their role in the pathogenesis of lung disease. PMID:26556381

  4. Alcohol, Aldehydes, Adducts and Airways.

    PubMed

    Sapkota, Muna; Wyatt, Todd A

    2015-11-05

    Drinking alcohol and smoking cigarettes results in the formation of reactive aldehydes in the lung, which are capable of forming adducts with several proteins and DNA. Acetaldehyde and malondialdehyde are the major aldehydes generated in high levels in the lung of subjects with alcohol use disorder who smoke cigarettes. In addition to the above aldehydes, several other aldehydes like 4-hydroxynonenal, formaldehyde and acrolein are also detected in the lung due to exposure to toxic gases, vapors and chemicals. These aldehydes react with nucleophilic targets in cells such as DNA, lipids and proteins to form both stable and unstable adducts. This adduction may disturb cellular functions as well as damage proteins, nucleic acids and lipids. Among several adducts formed in the lung, malondialdehyde DNA (MDA-DNA) adduct and hybrid malondialdehyde-acetaldehyde (MAA) protein adducts have been shown to initiate several pathological conditions in the lung. MDA-DNA adducts are pre-mutagenic in mammalian cells and induce frame shift and base-pair substitution mutations, whereas MAA protein adducts have been shown to induce inflammation and inhibit wound healing. This review provides an insight into different reactive aldehyde adducts and their role in the pathogenesis of lung disease.

  5. Effect of Michael adduction on peptide preservation in natural waters.

    PubMed

    McKee, G A; Kobiela, M E; Hatcher, P G

    2014-09-20

    The reaction of peptides with chemicals already present in natural waters (such as polycyclic aromatic hydrocarbons) is one method that has been suggested to preserve peptides for the longer term. In this study we test whether the reaction of tetrapeptides with a model quinone can help stabilise the peptide in one polluted riverine system, Elizabeth River in Virginia, USA. We found that there is almost no difference in rate constants between the peptide and its quinone adduct (e.g. 6.62 versus 6.86 per day for AVFA and its respective adduct). However, when monitoring the removal of the adduct from natural water, we identified two new compounds that are formed as a result of its decomposition. Using tandem mass spectrometry we identified potential structures and mechanisms for the formation of these new compounds. These new compounds are more recalcitrant than their parent peptide-quinone adduct, since they remain in solution for 3-10 times longer. Based on our findings we postulate that the reaction of peptides with quinones can help preserve sections of the original peptide following an initial rearrangement of the original adduct, potentially explaining why seemingly labile peptides are observed in most natural waters.

  6. Formation and persistence of benzo(a)pyrene metabolite-DNA adducts.

    PubMed Central

    Stowers, S J; Anderson, M W

    1985-01-01

    Benzo(a)pyrene (BP) and other polycyclic aromatic hydrocarbons (PAH) are ubiquitous environmental pollutants and are suspected to be carcinogenic in man. The in vivo formation of BP metabolite-DNA adducts has been characterized in a variety of target and nontarget tissues of mice and rabbits. Tissues included were lung, liver, forestomach, colon, kidney, muscle, and brain. The major adduct identified in each tissue was the (+)-7 beta,8 alpha-dihydroxy-9 alpha,10 alpha-epoxy-7,8,9,10-tetrahydro-BP (BPDEI)-deoxyguanosine adduct. A 7 beta, 8 alpha-dihydroxy-9 beta,10 beta-epoxy-7,8,9,10-tetrahydro-BP (BPDEII)-deoxyguanosine adduct, a (-)-BPDEI-deoxyguanosine adduct, and an unidentified adduct were also observed. The adduct levels are unexpectedly similar in all the tissues examined from the same BP-treated animal. For example, the BPDEI-DNA adduct levels in muscle and brain of mice were approximately 50% of those in lung and liver at each oral BP dose used. We have also examined adduct levels formed in vivo in several cell types of lung and liver. Macrophages, type II cells, and Clara cells from lung and hepatocytes and nonpparenchymal cells from liver were isolated from BP-treated rabbits. BPDEI-deoxyguanosine adduct was observed in each cell type and, moreover, the levels were similar in various cell types. These and previous results strongly suggest that DNA in many human tissues is continuously damaged from known exposure of humans to BP and other PAH. Moreover, DNA adducts formed from BP are persistent in lung and brain.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:4085435

  7. In vitro characterization of DNA adducts formed by foundry air particulate matter.

    PubMed

    Savela, K; Kohan, M J; Walsh, D; Perera, F P; Hemminki, K; Lewtas, J

    1996-05-01

    This study is part of an ongoing investigation of biomarkers in iron foundry workers exposed to polycyclic aromatic compounds. Foundry workers with the highest exposures had elevated levels of DNA adducts in their white blood cells in previous studies. The purpose of this study was to characterize the nature of DNA reactive chemicals in foundry air samples through incubating the foundry filter extract with DNA and activation enzymes. Calf thymus DNA was incubated with foundry filter extract and activated by either rat liver activation mixture (S9 mix) or xanthine oxidase. A complex pattern of adducts was observed on thin-layer chromatography (TLC) by the 32P-postlabeling assay. Two selected polycyclic aromatic hydrocarbons (PAHs)--1-NP-and anti(+/-)benzo[a]pyrene-trans-7,8-dihydrodiol-9,10-epoxide [anti(+/-) BPDE]-DNA adducts--were used as marker compounds in characterizing the postlabeled DNA adducts by TLC combined with high-performance liquid chromatography (HPLC). After an initial separation of DNA adducts by TLC, individual spots were isolated and separated further on HPLC. HPLC analysis and spiking with anti(+/-)BPDE-DNA standard confirmed the co-migration of the anti(+/-)BPDE-DNA standard with one PAH adduct formed by the S9 mix-activated DCM extract in calf thymus DNA.

  8. In vitro characterization of DNA adducts formed by foundry air particulate matter.

    PubMed Central

    Savela, K; Kohan, M J; Walsh, D; Perera, F P; Hemminki, K; Lewtas, J

    1996-01-01

    This study is part of an ongoing investigation of biomarkers in iron foundry workers exposed to polycyclic aromatic compounds. Foundry workers with the highest exposures had elevated levels of DNA adducts in their white blood cells in previous studies. The purpose of this study was to characterize the nature of DNA reactive chemicals in foundry air samples through incubating the foundry filter extract with DNA and activation enzymes. Calf thymus DNA was incubated with foundry filter extract and activated by either rat liver activation mixture (S9 mix) or xanthine oxidase. A complex pattern of adducts was observed on thin-layer chromatography (TLC) by the 32P-postlabeling assay. Two selected polycyclic aromatic hydrocarbons (PAHs)--1-NP-and anti(+/-)benzo[a]pyrene-trans-7,8-dihydrodiol-9,10-epoxide [anti(+/-) BPDE]-DNA adducts--were used as marker compounds in characterizing the postlabeled DNA adducts by TLC combined with high-performance liquid chromatography (HPLC). After an initial separation of DNA adducts by TLC, individual spots were isolated and separated further on HPLC. HPLC analysis and spiking with anti(+/-)BPDE-DNA standard confirmed the co-migration of the anti(+/-)BPDE-DNA standard with one PAH adduct formed by the S9 mix-activated DCM extract in calf thymus DNA. Images Figure 1. A Figure 1. B Figure 1. C Figure 1. D Figure 1. E Figure 1. F PMID:8781406

  9. Infrared spectroscopy of fullerene C60/anthracene adducts

    NASA Astrophysics Data System (ADS)

    García-Hernández, D. A.; Cataldo, F.; Manchado, A.

    2013-09-01

    Recent Spitzer Space Telescope observations of several astrophysical environments such as planetary nebulae, reflection nebulae and R Coronae Borealis stars show the simultaneous presence of mid-infrared features attributed to neutral fullerene molecules (i.e. C60) and polycyclic aromatic hydrocarbons (PAHs). If C60 fullerenes and PAHs coexist in fullerene-rich space environments, then C60 may easily form adducts with a number of different PAH molecules, at least with catacondensed PAHs. Here we present the laboratory infrared spectra (˜2-25 μm) of C60 fullerene and anthracene Diels-Alder mono- and bis-adducts as produced by sonochemical synthesis. We find that C60/anthracene Diels-Alder adducts display spectral features strikingly similar to those from C60 (and C70) fullerenes and other unidentified infrared emission features. Thus, fullerene adducts - if formed under astrophysical conditions and are stable/abundant enough - may contribute to the infrared emission features observed in fullerene-containing circumstellar/interstellar environments.

  10. Persistence of benzo[a]pyrene--DNA adducts in hematopoietic tissues and blood of the mummichog, Fundulus heteroclitus.

    PubMed

    Rose, W L; French, B L; Reichert, W L; Faisal, M

    2001-05-01

    The formation and persistence of benzo[a]pyrene (B[a]P)-DNA adducts were investigated in blood, liver and two hematopoietic tissues (anterior kidney and spleen) of the mummichog (Fundulus heteroclitus). Fish were injected with a single, sublethal dose of B[a]P (12 mg/kg body weight) and sampled from 8 to 96 days post-injection. 32P-Postlabeling analysis and storage phosphor imaging were used to resolve and quantify hydrophobic DNA adducts. One major DNA adduct was present in each of the examined tissues at all sampling times. This adduct had similar chromatographic characteristics to those of the adduct standard, 7R,8S,9S-trihydroxy-10S-(N(2)-deoxyguanosyl-3'-phosphate)-7,8,9,10-tetrahydro-benzo[a]pyrene (B[a]PDE-dG). Minor DNA adduct spots, representing less than 2% of the total DNA adducts, were observed in some liver, anterior kidney and spleen samples for up to 32 days post-injection. The B[a]P-DNA adducts reached maximal levels at 32 days post-injection and persisted for at least 96 days in all examined tissues. B[a]P-DNA adduct levels were significantly higher in the liver and anterior kidney than in the spleen from 16 to 96 days (P<0.001), although liver and anterior kidney DNA adduct levels were not significantly different at any time. This is the first controlled study to demonstrate the formation and persistence of B[a]P-DNA adducts in hematopoietic tissues and blood of fishes exposed to the prototypical polycyclic aromatic hydrocarbon, B[a]P. Although persistent DNA adducts are generally recognized as potential initiators of carcinogenic processes, adducts in these vital tissues may also lead to disruption of physiological functions such defense mechanisms and hematopoiesis.

  11. DNA adducts induced by in vitro activation of extracts of diesel and biodiesel exhaust particles.

    PubMed

    Ross, Jeffrey A; Nelson, Garret B; Mutlu, Esra; Warren, Sarah H; Gilmour, M Ian; DeMarini, David M

    2015-01-01

    Biodiesel and biodiesel-blend fuels offer a renewable alternative to petroleum diesel, but few data are available concerning the carcinogenic potential of biodiesel exhausts. We compared the formation of covalent DNA adducts by the in vitro metabolic activation of organic extracts of diesel-exhaust particles (DEP) from petroleum diesel and soy biodiesel and correlated DNA adduct levels and mutagenicity in Salmonella TA100. We examined two different DEP from petroleum diesel (C-DEP and B0), one from soy bean oil biodiesel (B100) and one from combustion of a blend of 20% B100 and 80% B0 (B20) for in vitro DNA adduct-forming potential under oxidative or nitroreductive conditions in the presence of calf thymus DNA as well as in vivo in Salmonella TA100. The modified DNA was hydrolyzed and analyzed by (32)P-postlabeling using either butanol extraction or nuclease P1 pre-enrichment. Multiple DNA adducts were produced with chromatographic mobilities consistent with PAH and nitro-PAH adducts. The types and quantities of DNA adducts produced by the two independent petroleum diesel DEP were similar, with both polycyclic aromatic hydrocarbon (PAH)- and nitro-PAH-derived adducts formed. Relative potencies for S9-mediated DNA adduct formation, either per mass of particulate or per MJ(th) energy consumed were B100 > B0 > B20. Soy biodiesel emissions induced DNA damage in the form of presumptive PAH and nitro-PAH DNA adducts that correlated with mutagenicity in Salmonella. B20 is the soy biodiesel used most commonly in the US, and it produced the lowest DNA adduct-emission factor, ∼50% that of petroleum diesel.

  12. Analysis of serum PAH`s and PAH adducts by LC/MS

    SciTech Connect

    McClure, P.C.; Barr, J.R.; Maggio, V.L.

    1995-12-31

    Polycyclic aromatic hydrocarbons are an important class of chemical carcinogens. Benzo[a]pyrene is the most extensively studied and best understood carcinogenic PAH It is believed that Benzo[a]pyrene is metabolized in vitro to the diol epoxide, Benzo[a]pyrene-7,8-dihydrodiol-9, 10-epoxide which then can react with various nucleophilic centers on DNA. The major alkylation product appears to be the reaction of the Benzo[a]pyrene diol epoxide with the N{sup 2} position of guanine sites on DNA. Methods that can measure exposure and biological response to carcinogens such as PAH`s are needed. Human Blood can be separated into plasma, lymphocytes, and red blood cells. The plasma should contain native PAH`s which may yield some useful information about recent exposure. The red blood cells contain hemoglobin and adducts of PAH`s. Hemoglobin has an average lifetime of 120 days so quantification of hemoglobin adducts should give an average of a persons exposure over four months. Also, the electrophilic metabolites that react with hemoglobin to form adducts are the same metabolites that form DNA adducts which can lead to mutations and cancer. Lymphocytes contain DNA and therefore DNA adducts. DNA adducts can be repaired by a series of enzymes so quantification of these adducts will only yield information about recent or non-repairable adducts. DNA adduct formation is believed to be the first important step in chemical carcinogenesis so quantification of these adducts should yield some information on exposure and a great deal of important data on biological response and risk from specific PAH`s.

  13. Molecular dosimetry of aromatic amines in human populations

    SciTech Connect

    Skipper, P.L.; Tannenbaum, S.R.

    1994-10-01

    Certain aromatic amines carcinogenic for the human urinary bladder, such as 4-aminobiphenyl, undergo hepatic metabolic activation to N-hydroxylamines, which are transported to the bladder. During the transport process, these reactive species come in contact with hemoglobin and react with this blood protein. The principal hemoglobin adduct formed is a cysteine sulfinamide, and quantitative methods have been developed for the analysis of sulfinamide adducts at the levels present in ordinary human blood specimens. N-acetylation is an alternative metabolic fate to N-hydroxylation. The amount of hemoglobin adduct is decreased to the extent that this pathway is increased relative to N-hydroxylation. Thus, the hemoglobin adduct is sensitive to dose, cytochrome P-450-mediated activation, and N-acetyltransferase-mediated detoxification. In addition, it has been shown that DNA adduct concentration of 4-aminobiphenyl present in human bladder epithelial cells is significantly associated with hemoglobin adduct levels. Thus, the hemoglobin adduct of 4-aminobiphenyl, and perhaps several other aromatic amines, is a good dosimeter for the target tissue dose of the ultimate carcinogenic metabolite of these amines. Several studies have been undertaken in which the hemoglobin adducts of aminobiphenyls in human blood specimens were determined quantitatively. Information concerning exposure status and acetylator phenotype of the same individuals was obtained simultaneously. The results of these studies indicate that the hemoglobin adduct of 4-aminobiphenyl is closely associated with three major risk factors for bladder cancer; cigarette smoking, type of tobacco smoked, and acetylator phenotype. They also support a major etiologic role for aromatic amines in much of human bladder cancer. 42 refs., 4 figs., 1 tab.

  14. A Facile Solid‐Phase Route to Renewable Aromatic Chemicals from Biobased Furanics

    PubMed Central

    Thiyagarajan, Shanmugam; Genuino, Homer C.; van der Waal, Jan C.; Weckhuysen, Bert M.; van Haveren, Jacco

    2015-01-01

    Abstract Renewable aromatics can be conveniently synthesized from furanics by introducing an intermediate hydrogenation step in the Diels–Alder (DA) aromatization route, to effectively block retro‐DA activity. Aromatization of the hydrogenated DA adducts requires tandem catalysis, using a metal‐based dehydrogenation catalyst and solid acid dehydration catalyst in toluene. Herein it is demonstrated that the hydrogenated DA adducts can instead be conveniently converted into renewable aromatics with up to 80 % selectivity in a solid‐phase reaction with shorter reaction times using only an acidic zeolite, that is, without solvent or dehydrogenation catalyst. Hydrogenated adducts from diene/dienophile combinations of (methylated) furans with maleic anhydride are efficiently converted into renewable aromatics with this new route. The zeolite H‐Y was found to perform the best and can be easily reused after calcination. PMID:26684008

  15. A Facile Solid-Phase Route to Renewable Aromatic Chemicals from Biobased Furanics.

    PubMed

    Thiyagarajan, Shanmugam; Genuino, Homer C; van der Waal, Jan C; de Jong, Ed; Weckhuysen, Bert M; van Haveren, Jacco; Bruijnincx, Pieter C A; van Es, Daan S

    2016-01-22

    Renewable aromatics can be conveniently synthesized from furanics by introducing an intermediate hydrogenation step in the Diels-Alder (DA) aromatization route, to effectively block retro-DA activity. Aromatization of the hydrogenated DA adducts requires tandem catalysis, using a metal-based dehydrogenation catalyst and solid acid dehydration catalyst in toluene. Herein it is demonstrated that the hydrogenated DA adducts can instead be conveniently converted into renewable aromatics with up to 80% selectivity in a solid-phase reaction with shorter reaction times using only an acidic zeolite, that is, without solvent or dehydrogenation catalyst. Hydrogenated adducts from diene/dienophile combinations of (methylated) furans with maleic anhydride are efficiently converted into renewable aromatics with this new route. The zeolite H-Y was found to perform the best and can be easily reused after calcination.

  16. Methodologies for bulky DNA adduct analysis and biomonitoring of environmental and occupational exposures.

    PubMed

    de Kok, T M C M; Moonen, H J J; van Delft, J; van Schooten, F J

    2002-10-05

    It is undisputed that DNA adduct formation is one of the key processes in early carcinogenesis. Therefore, analysis of DNA adduct levels may be one of the best tools available to characterize exposure to complex mixtures of genotoxic chemicals as occurring in different environmental and occupational exposure settings. However, from an analytical point of view the detection and quantification of DNA adducts is a challenging enterprise as extremely high sensitivity and selectivity are required. The entire spectrum of chromatographic techniques, including thin-layer chromatography (TLC), gas and liquid chromatography as well as capillary electrophoresis has been used in combination with different detection systems, all with their own specific characteristics. Among the various combinations of techniques, the TLC-(32)P-postlabeling combination appears to meet best with criteria of sensitivity and requirements of minimal amounts of material. Recent developments in the application of capillary electrophoresis in combination with either immunochemical or mass spectrometric detection techniques may offer new and promising approaches, with higher selectivity as compared to TLC-(32)P postlabeling. The applicability of these new techniques in biomonitoring studies aiming at the exposure and risk assessment of low and chronic exposures remains to be determined. In this paper we compare and discuss the advantages and limitations of different techniques used in DNA adduct analysis, with specific emphasis on those adducts formed by the polycyclic aromatic hydrocarbons and heterocyclic aromatic amines. Copyright 2002 Elsevier Science B.V.

  17. Conformational evaluation of DNA-carcinogen adducts using semi-empirical potential energy calculations

    SciTech Connect

    Verna, L.K.

    1992-01-01

    The covalent attachment of an aromatic amine to guanine C8 can produce a conformational change within the DNA molecule. This conformational change is likely to influence the altered DNA's biological capacity. The author used semi-empirical potential energy calculations to evaluate conformational patterns of DNA-aromatic amine adducts using the series: aniline, 4-aminobiphenyl, 2-aminofluorene and 1-aminopyrene. An exhaustive search was made of the conformational space for carcinogen modified two-base sequences. Information was incorporated into single stranded modified trimers. Modified strands were incorporated in duplex trimers. Nine-base modified duplexes were constructed and evaluated. This procedure produced distinctly different patterns for each aromatic amine investigated. It was apparent that the base sequence in which the carcinogen modification was found was crucial to the conformational change produced. At the dimer level, aniline allows both syn and anti guanine orientations at the carcinogen modification site. There were base-base and base-carcinogen stacked states, suggesting a flexible adduct easily able to assume many conformations. 4-Aminobiphenyl attachment resulted in low energy base-carcinogen stacked states, and a guanine torsion predominantly in a low syn orientation. The flexibility of this adduct was greatly reduced from that of the aniline adduct. 2-Aminofluorene adducts assumed more of a conformational mix. The major portion was base-base stacked with modified guanine anti, with a portion with base-carcinogen stacking and guanine syn or low syn. 1-Aminopyrene adducts were inflexible. The majority assumed a base-carcinogen stack with guanine syn. The conformational profiles of large modified pieces provided details of a unique low energy wedge conformation, in which aminofluorene, particularly, was able to fit into the minor groove with very little helix distortion.

  18. BIOMARKERS OF POLYCYCLIC AROMATIC HYDROCARBON-DNA DAMAGE AND CIGARETTE SMOKE EXPOSURES IN PAIRED MATERNAL AND NEWBORN BLOOD SAMPLES AS A MEASURE OF DIFFERENTIAL SUSCEPTIBILITY. (R827027)

    EPA Science Inventory

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  19. DNA adduct formation in precision-cut rat liver and lung slices exposed to benzo[a]pyrene.

    PubMed

    Harrigan, Jeanine A; Vezina, Chad M; McGarrigle, Barbara P; Ersing, Noreen; Box, Harold C; Maccubbin, Alexander E; Olson, James R

    2004-02-01

    Chemical-DNA adducts provide an integrated measure of exposure, absorption, bioactivation, detoxification, and DNA repair following exposure to a genotoxic agent. Benzo[a]pyrene (BaP), a prototypical polycyclic aromatic hydrocarbon (PAH), can be bioactivated by cytochrome P-450s (CYPs) and epoxide hydrolase to genotoxic metabolites which form covalent adducts with DNA. In this study, we utilized precision-cut rat liver and lung slices exposed to BaP to investigate tissue-specific differences in chemical absorption and formation of DNA adducts. To investigate the contribution of bioactivating CYPs (such as CYP1A1 and CYP1B1) on the formation of BaP-DNA adducts, animals were also pretreated in vivo with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD, dioxin) prior to in vitro incubation of tissue slices with BaP. Furthermore, the tissue distribution of BaP and BaP-DNA adduct levels from in vivo studies were compared with those from the in vitro tissue slice experiments. The results indicate a time- and concentration-dependent increase in tissue-associated BaP following exposure of rat liver and lung tissue slices to BaP in vitro, with generally higher levels of BaP retained in lung tissue. Furthermore, rat liver and lung slices metabolized BaP to reactive intermediates that formed covalent adducts with DNA. Total BaP-DNA adducts increased with concentration and incubation time. Adduct levels (fmol adduct/microg DNA) in lung slices were greater than liver at all doses. Liver slices contained one major and two minor adducts, while lung slices contained two major and 3 minor adducts. The tissue-specific qualitative profile of these adducts in tissue slices was similar to that observed from in vivo studies, further validating the use of this model. Pretreatment of animals with TCDD prior to in vitro incubation with BaP potentiated the levels of DNA adduct formation. TCDD pretreatment altered the adduct distribution in lung but not in liver slices. Together, the results

  20. Formation and Repair of Tobacco Carcinogen-Derived Bulky DNA Adducts

    DOE PAGES

    Hang, Bo

    2010-01-01

    DNA adducts play a central role in chemical carcinogenesis. The analysis of formation and repair of smoking-related DNA adducts remains particularly challenging as both smokers and nonsmokers exposed to smoke are repetitively under attack from complex mixtures of carcinogens such as polycyclic aromatic hydrocarbons and N -nitrosamines. The bulky DNA adducts, which usually have complex structure, are particularly important because of their biological relevance. Several known cellular DNA repair pathways have been known to operate in human cells on specific types of bulky DNA adducts, for example, nucleotide excision repair, base excision repair, and direct reversal involving O 6more » -alkylguanine DNA alkyltransferase or AlkB homologs. Understanding the mechanisms of adduct formation and repair processes is critical for the assessment of cancer risk resulting from exposure to cigarette smoke, and ultimately for developing strategies of cancer prevention. This paper highlights the recent progress made in the areas concerning formation and repair of bulky DNA adducts in the context of tobacco carcinogen-associated genotoxic and carcinogenic effects.« less

  1. Detection and characterization of DNA adducts formed from metabolites of the fungicide ortho-phenylphenol.

    PubMed

    Zhao, Shouxun; Narang, Amarjit; Gierthy, John; Eadon, George

    2002-05-22

    The significance of DNA adduction in ortho-phenylphenol-induced carcinogenesis remains unclear. Establishing adduct structures may contribute to resolving this issue. The chemical structures of the DNA adduction products resulting from the in vitro reaction of phenylbenzoquinone, the putative ultimate carcinogenic metabolite of the fungicide/disinfectant ortho-phenylphenol, are reported here. Three isomeric adducts that resulted from reaction of deoxyguanosine were characterized by UV, LC-ESI-MS, and MS/MS, and 1D and 2D COSY-NMR spectroscopy. The proposed mechanism of product formation is nucleophilic attack by the deoxyguanosine exocyclic amine nitrogen on an electrophilic quinone carbon, followed by stabilization through enolization. Another nucleophilic attack forms a five-membered ring, which aromatizes by dehydration to form the final product. Adducts were also characterized from deoxyadenosine and deoxycytidine, although conversions were at least 10 times lower. Structures are also proposed for these products. Cell culture studies confirmed that HepG2 cells incubated with phenylbenzoquinone at concentrations associated with cytotoxicity form the same DNA adducts.

  2. Formation and Repair of Tobacco Carcinogen-Derived Bulky DNA Adducts

    PubMed Central

    Hang, Bo

    2010-01-01

    DNA adducts play a central role in chemical carcinogenesis. The analysis of formation and repair of smoking-related DNA adducts remains particularly challenging as both smokers and nonsmokers exposed to smoke are repetitively under attack from complex mixtures of carcinogens such as polycyclic aromatic hydrocarbons and N-nitrosamines. The bulky DNA adducts, which usually have complex structure, are particularly important because of their biological relevance. Several known cellular DNA repair pathways have been known to operate in human cells on specific types of bulky DNA adducts, for example, nucleotide excision repair, base excision repair, and direct reversal involving O6-alkylguanine DNA alkyltransferase or AlkB homologs. Understanding the mechanisms of adduct formation and repair processes is critical for the assessment of cancer risk resulting from exposure to cigarette smoke, and ultimately for developing strategies of cancer prevention. This paper highlights the recent progress made in the areas concerning formation and repair of bulky DNA adducts in the context of tobacco carcinogen-associated genotoxic and carcinogenic effects. PMID:21234336

  3. Cigarette smoke-induced DNA adducts in the respiratory and nonrespiratory tissues of rats

    SciTech Connect

    Gairola, C.G.; Gupta, R.C. )

    1991-01-01

    Formation of DNA adducts is regarded as an essential initial step in the process of chemical carcinogenesis. To determine how chronic exposure to cigarette smoke affects the distribution of DNA adducts in selected respiratory and nonrespiratory tissues. The authors exposed male Sprague-Dawley rats daily to fresh mainstream smoke from the Univ. of Kentucky reference cigarettes (2R1) in a nose-only exposure system for 32 weeks. Blood carboxyhemoglobin, total particulate matter (TPM) intake, and pulmonary aryl hydrocarbon hydroxylase values indicated effective exposure of animals to cigarette smoke. DNA was extracted from three respiratory (larynx, trachea, and lung) and three nonrespiratory (liver, heart, and bladder) tissues and analyzed for DNA adducts by the {sup 32}P-postlabeling assay under conditions capable of detecting low levels of diverse aromatic/hydrophobic adducts. Data showed that the total DNA adducts in the lung, heart, and trachea, and larynx were increased by 10- to 20-fold in the smoke-exposed group. These data suggest selective formation of DNA adducts in the tissues.

  4. Mutations Induced by Benzo[a]pyrene and Dibenzo[a,l]pyrene in lacI Transgenic B6C3F1 Mouse Lung Result from Stable DNA Adducts

    EPA Science Inventory

    Dibenzo[a,l]pyrene (DB[a,l]P) and benzo[a]pyrene (B[a]P) are carcinogenic polycyclic aromatic hydrocarbons (PAH) that are each capable of forming a variety of covalent adducts with DNA. Some of the DNA adducts formed by these PAHs have been demonstrated to spontaneously depurina...

  5. Mutations Induced by Benzo[a]pyrene and Dibenzo[a,l]pyrene in lacI Transgenic B6C3F1 Mouse Lung Result from Stable DNA Adducts

    EPA Science Inventory

    Dibenzo[a,l]pyrene (DB[a,l]P) and benzo[a]pyrene (B[a]P) are carcinogenic polycyclic aromatic hydrocarbons (PAH) that are each capable of forming a variety of covalent adducts with DNA. Some of the DNA adducts formed by these PAHs have been demonstrated to spontaneously depurina...

  6. Supramolecular aromaticity

    NASA Astrophysics Data System (ADS)

    Karabıyık, Hande; Sevinçek, Resul; Karabıyık, Hasan

    2014-05-01

    We report experimental and theoretical evidences for supramolecular aromaticity as a new concept to be widely used in researches about molecular crystals. CSD survey regarding frequently encountered resonance-assisted H-bonds (RAHBs) in formic acid, formamide, formimidamide, formic acid-formamide, and formamide-formimidamide dimers shows that supramolecular quasirings formed by RAHBs have remarkable electronic delocalization within themselves, which is reminiscent of aromaticity at supramolecular level. This study criticizes and reevaluates the validity of conventional judgment which states that ring systems formed by intermolecular H-bonds cannot be aromatic. Thus, the term aromaticity can be extended to supramolecular systems formed by RAHBs. Supramolecular aromaticity has a multi-fold nature involving both σ- and π-delocalization, and σ-delocalization through RAHBs takes on a task of compensating σ-deficiency within quasirings. Atomic composition in donor-acceptor set of the dimers is descriptive for supramolecular aromaticity. We revised bond-valence parameters for RAHBs and they suggest that hypervalent character of H atoms is more pronounced than their hypovalent character in RAHBs. The σ-delocalized bonding within H-bonded quasirings necessitates hypervalent character of H atoms. Quantum chemical calculations based on adiabatic Hydrogen Atom Transfer (HAT) between the monomers reveal that topological parameters at ring critical points (RCPs) of the quasirings correlate well with Shannon's entropic aromaticity index. The presence of additional LP orbital on O atoms implying more diffused LP-orbitals in donor-acceptor set leads to the formation of resonance-disabling states reducing supramolecular aromaticity of a quasiring and energetic cost of the electron transfer between the monomers. There is a nonignorable electron transfer between the monomers even in the cases where H atoms are close to donor or acceptor atom. NBO analyses have revealed that

  7. Detection of Benzo[a]pyrene-Guanine Adducts in Single-Stranded DNA using the α-Hemolysin Nanopore

    PubMed Central

    Perera, Rukshan T.; Fleming, Aaron M.; Johnson, Robert P.; Burrows, Cynthia J.; White, Henry S.

    2017-01-01

    The carcinogenic precursor benzo[a]pyrene (BP), a polycyclic aromatic hydrocarbon, is released into the environment through the incomplete combustion of hydrocarbons. Metabolism of BP in the human body yields a potent alkylating agent (benzo[a]pyrene diol epoxide, BPDE) that reacts with guanine (G) in DNA to form an adduct implicated in cancer initiation. We report that the α-hemolysin (αHL) nanopore platform can be used to detect a BPDE adduct to G in synthetic oligodeoxynucleotides. Translocation of a 41-mer poly-2′-deoxycytidine strand with a centrally located BPDE adduct to G through αHL in 1 M KCl produces a unique multi-level current signature allowing the adduct to be detected. This readily distinguishable current modulation was observed when the BPDE-adducted DNA strand translocated from either the 5′ or 3′ directions. This study suggests that BPDE adducts and other large aromatic biomarkers can be detected with αHL, presenting opportunities for the monitoring, quantification, and sequencing of mutagenic compounds from cellular DNA samples. PMID:25629967

  8. Detection of benzo[a]pyrene-guanine adducts in single-stranded DNA using the α-hemolysin nanopore.

    PubMed

    Perera, Rukshan T; Fleming, Aaron M; Johnson, Robert P; Burrows, Cynthia J; White, Henry S

    2015-02-20

    The carcinogenic precursor benzo[a]pyrene (BP), a polycyclic aromatic hydrocarbon, is released into the environment through the incomplete combustion of hydrocarbons. Metabolism of BP in the human body yields a potent alkylating agent (benzo[a]pyrene diol epoxide, BPDE) that reacts with guanine (G) in DNA to form an adduct implicated in cancer initiation. We report that the α-hemolysin (αHL) nanopore platform can be used to detect a BPDE adduct to G in synthetic oligodeoxynucleotides. Translocation of a 41-mer poly-2'-deoxycytidine strand with a centrally located BPDE adduct to G through αHL in 1 M KCl produces a unique multi-level current signature allowing the adduct to be detected. This readily distinguishable current modulation was observed when the BPDE-adducted DNA strand translocated from either the 5' or 3' directions. This study suggests that BPDE adducts and other large aromatic biomarkers can be detected with αHL, presenting opportunities for the monitoring, quantification, and sequencing of mutagenic compounds from cellular DNA samples.

  9. Detection of benzo[a]pyrene-guanine adducts in single-stranded DNA using the α-hemolysin nanopore

    NASA Astrophysics Data System (ADS)

    Perera, Rukshan T.; Fleming, Aaron M.; Johnson, Robert P.; Burrows, Cynthia J.; White, Henry S.

    2015-02-01

    The carcinogenic precursor benzo[a]pyrene (BP), a polycyclic aromatic hydrocarbon, is released into the environment through the incomplete combustion of hydrocarbons. Metabolism of BP in the human body yields a potent alkylating agent (benzo[a]pyrene diol epoxide, BPDE) that reacts with guanine (G) in DNA to form an adduct implicated in cancer initiation. We report that the α-hemolysin (αHL) nanopore platform can be used to detect a BPDE adduct to G in synthetic oligodeoxynucleotides. Translocation of a 41-mer poly-2‧-deoxycytidine strand with a centrally located BPDE adduct to G through αHL in 1 M KCl produces a unique multi-level current signature allowing the adduct to be detected. This readily distinguishable current modulation was observed when the BPDE-adducted DNA strand translocated from either the 5‧ or 3‧ directions. This study suggests that BPDE adducts and other large aromatic biomarkers can be detected with αHL, presenting opportunities for the monitoring, quantification, and sequencing of mutagenic compounds from cellular DNA samples.

  10. UVR exposure sensitizes keratinocytes to DNA adduct formation.

    PubMed

    Nair, Sudhir; Kekatpure, Vikram D; Judson, Benjamin L; Rifkind, Arleen B; Granstein, Richard D; Boyle, Jay O; Subbaramaiah, Kotha; Guttenplan, Joseph B; Dannenberg, Andrew J

    2009-10-01

    UV radiation (UVR) and exposure to tobacco smoke, a source of polycyclic aromatic hydrocarbons (PAH), have been linked to skin carcinogenesis. UVR-mediated activation of the aryl hydrocarbon receptor (AhR) stimulates the transcription of CYP1A1 and CYP1B1, which encode proteins that convert PAH to genotoxic metabolites. We determined whether UVR exposure sensitized human keratinocytes to PAH-induced DNA adduct formation. UVR exposure induced CYP1A1 and CYP1B1 in HaCaT cells, an effect that was mimicked by photooxidized tryptophan (aTRP) and FICZ, a component of aTRP. UVR exposure or pretreatment with aTRP or FICZ also sensitized cells to benzo(a)pyrene (B[a]P)-induced DNA adduct formation. alphaNF, an AhR antagonist, suppressed UVR-, aTRP-, and FICZ-mediated induction of CYP1A1 and CYP1B1 and inhibited B[a]P-induced DNA adduct formation. Treatment with 17-AAG, an Hsp90 inhibitor, caused a marked decrease in levels of AhR; inhibited UVR-, aTRP-, and FICZ-mediated induction of CYP1A1 and CYP1B1; and blocked the sensitization of HaCaT cells to B[a]P-induced DNA adduct formation. FICZ has been suggested to be a physiologic ligand of the AhR that may have systemic effects. Hence, studies of FICZ were also carried out in MSK-Leuk1 cells, a model of oral leukoplakia. Pretreatment with alpha-naphthoflavone or 17-AAG blocked FICZ-mediated induction of CYP1A1 and CYP1B1, and suppressed the increased B[a]P-induced DNA adduct formation. Collectively, these results suggest that sunlight may activate AhR signaling and thereby sensitize cells to PAH-mediated DNA adduct formation. Antagonists of AhR signaling may have a role in the chemoprevention of photocarcinogenesis.

  11. DNA adducts induced by the potential human carcinogen cyclopenta[cd]pyrene using [sup 32]P-postlabeling

    SciTech Connect

    Beach, A.C.

    1993-01-01

    Cyclopenta[cd]pyrene (CPP) is a widespread polycyclic aromatic hydrocarbon with potent mutagenic and carcinogenic activity. CPP is of interest for its prevalence in such notable sources of human exposure to environmental pollution as automotive/diesel engine exhaust emissions. As DNA adduct formation represents an integral phase in the chemical carcinogenesis process, the following studies were undertaken to determine: (1) the utility [sup 32]P-postlabeling for detecting CPP-DNA adducts; (2) the potency and efficacy of CPP to induce DNA adducts in vivo; and (3) the identity of the ultimate mutagenic intermediate(s) of CPP in vivo. CPP-3,4-epoxide has been suggested as the ultimate mutagenic form of CPP. This epoxide was reacted with DNA and deoxynucleotide induced with those formed by CPP and the base-specificity of those adducts. CPP-3,4-epoxide induced at least four major and three minor DNA adducts at the level of deoxyguanosine. All adducts were similar to those formed by CPP in pilot in vivo studies; therefore the ability of CPP to induce adducts was further evaluated. CPP produced up to four major and seven minor adducts in the rat. CPP-DNA adducts were highest in the lung followed by the heart, WBCs, and liver. CPP was also found to induce adducts in vivo across a five orders of magnitude dosing range i.e. 1 [mu]g/kg-50 mg/kg. CPP adducts induced in vitro were found to increase in the presence of epoxide hydrolase inhibitors suggesting their epoxide origin. This prompted evaluation of the similarity of adducts induced by CPP in vivo with those produced by CPP-3,4-epoxide in vitro. Cochromatographic studies revealed that all four major and at least five of the minor adducts induced by CPP were formed by reaction of CPP-3,4-epoxide with deoxyguanosine; one adduct was clearly oxyadenosine derived. Finally, [sup 32]P-postlabeling was used to detect CPP-adducts in assays with potential for human application.

  12. {sup 32}P-postlabeling analysis of DNA adducts in wild perch (Perca fluviatilis) and northern pike (Esox lucius)

    SciTech Connect

    Ericson, G.; Liewenborg, B.; Balk, L.

    1995-12-31

    Several previous studies have demonstrated a correlation between high concentrations of sediment-associated contaminants and elevated levels of aromatic/hydrophobic DNA adduct levels in the liver of benthic fish species. In the present study DNA adducts was analyzed in coastal populations of perch (Perca fluviatilis) and northern pike (Esox lucius). Fish were sampled from four different sites in a gradient from a heavily industrialized area at the Swedish Baltic coast. For comparison, fish were also caught in a reference area with no main industries and comparatively low levels of contaminants of anthropogenic origin. DNA was extracted from liver and several extrahepatic tissues and DNA adducts were analyzed by the nuclease PI version of the {sup 32}P-postlabeling assay. The autoradiograms derived from DNA of fish from the contaminated sites showed several adduct spots not visible on the autoradiograms derived from fish from the reference area. Total adduct levels were significantly elevated in several tissues in fish from contaminated sites compared to the reference area. Species and tissue-specific differences in adduct levels and the use of {sup 32}P-postlabeling analysis of DNA adducts as a biomarker to monitor the presence and effects of genotoxic chemicals in the aquatic environment are discussed.

  13. Protein adduct biomarkers: State of the Art

    SciTech Connect

    Meyer, M.J.; Bechtold, W.E.

    1996-10-01

    Covalent protein adducts formed after exposure to xenobiotics may provide readily measurable indicators of these exposures, After adequate characterization of the dose-dependent formation of a specific adduct, the adduct can often be used as a quantitative marker for exposure, DNA adduct formation, or, possibly, risk of disease. By elucidating the structure of an adduct and studying the conditions under which it forms, information about the reactions that lead to its formation can be obtained. Continuing work in this area includes methods to expand the number, types, and levels of chemical exposures that can be studied by covalent adduct formation. In addition to the use of this technology in the field of occupational health, basic research in this area provides insights into metabolic pathways and biochemistry, as well. 26 refs., 1 fig.

  14. Screening of hydrophobic DNA adducts in flounder (Platichthys flesus) from the Baltic Sea.

    PubMed

    Malmström, C; Konn, M; Bogovski, S; Lang, T; Lönnström, L-G; Bylund, G

    2009-12-01

    Neoplasia and other histopathological lesions in flounder (Platichthys flesus) liver have been investigated in several European sea areas, including the Baltic Sea. Several studies have been able to link neoplasm epizootics in fish with the exposure to genotoxins such as polycyclic aromatic hydrocarbons (PAHs). The level of hydrophobic DNA adducts in tissue DNA reflects the exposure of the organism to PAHs. Using hydrophobic DNA adduct levels as biomarkers, possible PAH exposure was assessed in flounder from 10 different sites in the Baltic Sea, collected during the years 1995-1997. The results show that the overall levels of hepatic DNA adducts were low and, in general, the chromatograms appeared clean. The highest levels of DNA adducts were found at two sites in the southern Baltic Sea. There were no statistically significant differences in adduct levels between the sites. Our results indicate that flounder from studied off shore sites of the Baltic Sea had not been exposed to a greater extent to large polycyclic hydrophobic hydrocarbons in their environment.

  15. Characterization of Model Peptide Adducts with Reactive Metabolites of Naphthalene by Mass Spectrometry

    PubMed Central

    Pham, Nathalie T.; Jewell, William T.; Morin, Dexter; Jones, A. Daniel; Buckpitt, Alan R.

    2012-01-01

    Naphthalene is a volatile polycyclic aromatic hydrocarbon generated during combustion and is a ubiquitous chemical in the environment. Short term exposures of rodents to air concentrations less than the current OSHA standard yielded necrotic lesions in the airways and nasal epithelium of the mouse, and in the nasal epithelium of the rat. The cytotoxic effects of naphthalene have been correlated with the formation of covalent protein adducts after the generation of reactive metabolites, but there is little information about the specific sites of adduction or on the amino acid targets of these metabolites. To better understand the chemical species produced when naphthalene metabolites react with proteins and peptides, we studied the formation and structure of the resulting adducts from the incubation of model peptides with naphthalene epoxide, naphthalene diol epoxide, 1,2-naphthoquinone, and 1,4-naphthoquinone using high resolution mass spectrometry. Identification of the binding sites, relative rates of depletion of the unadducted peptide, and selectivity of binding to amino acid residues were determined. Adduction occurred on the cysteine, lysine, and histidine residues, and on the N-terminus. Monoadduct formation occurred in 39 of the 48 reactions. In reactions with the naphthoquinones, diadducts were observed, and in one case, a triadduct was detected. The results from this model peptide study will assist in data interpretation from ongoing work to detect peptide adducts in vivo as markers of biologic effect. PMID:22870282

  16. Mechanistic relationships between DNA adducts, oncogene mutations, and lung tumorigenesis in strain A mice.

    PubMed

    Nesnow, S; Ross, J A; Mass, M J; Stoner, G D

    1998-01-01

    This paper describes a series of studies on the lung tumorigenic activities of polycyclic aromatic hydrocarbons (PAHs) in strain A/J mice, their ability to form PAH-DNA adducts in lung tissues, and their ability to mutate the Ki-ras oncogene in PAH-induced tumors. Seven PAHs were studied: cyclopenta[cd]pyrene (CPP), benzo[a]pyrene (B[a]P), benzo[b]fluoranthene (B[b]F), dibenz[a,h] anthracene (DBA), 5-methylchrysene (5MC), benz[j]aceanthrylene (B[j]A), and dibenzo[a,l]pyrene (DB[a,l]P). The dose-response data for the PAHs revealed 100-fold differences in tumor potency based on dose, with the order of activity DB[a,l]P, DBA > B[j]A > 5MC > CPP B[a]P > B[b]F. Large differences in tumor multiplicity were also observed between the PAHs. DNA adducts were measured by 32P-postlabeling techniques on DNA from lungs of mice treated with these PAH's. DB[a,l]P gave syn- and anti-fjord-region diol-epoxide adducts of dAdo and dGuo; DBA gave both bay-region diol-epoxide-dGuo and bisdihydrodiol-epoxide adducts; CPP gave cyclopenta-ring-dGuo adducts; B[j]A gave a mixture of cyclopenta-ring-dGuo and -dAdo adducts; 5MC gave anti-bay-region diol-epoxide-dGuo adducts; B[a]P gave bay-region diol-epoxide-dGuo adducts; and B[b]F gave 5-hydroxy-B[b]F-diol-epoxide-dGuo adducts. Ki-ras codon 12 and 61 mutation analysis of PAH induced tumors was performed using PCR and dideoxy sequencing methods. DB[a,l]P gave both codon 12 and codon 61 mutations. High proportions of codon 12 TGT mutations from B[a]P-, B[b]F- and 5MC-, induced tumors and CGT mutations from CPP- and B[j]A-induced tumors were observed. DBA produced no mutations in Ki-ras codons 12 or 61 by direct sequencing. The interrelationships between the tumorigenesis, DNA adduct, and oncogene mutation data are discussed.

  17. DNA adduct formation among workers in a Thai industrial estate and nearby residents.

    PubMed

    Peluso, Marco; Srivatanakul, Petcharin; Munnia, Armelle; Jedpiyawongse, Adisorn; Meunier, Aurelie; Sangrajrang, Suleeporn; Piro, Sara; Ceppi, Marcello; Boffetta, Paolo

    2008-01-25

    The genotoxic effects of air pollutant exposures have been studied in people living and working in Map Ta Phut, Rayong province, Thailand, a site where is located the Map Ta Phut Industrial Estate (MIE) one of the largest steel, refinery and petrochemical complex in the South-Eastern Asia. This was done by the conduction of a transversal study aimed to compare the prevalence of bulky DNA adducts in groups of subjects experiencing various degree of air pollution. DNA adduct analysis was performed in the leukocytes of 201 volunteers by the (32)P-postlabelling assay: 79 were workers in the MIE complex, including 24 refinery workers, 40 steel workers and 15 tinplate workers, 72 were people residing downwind in the MIE area and 50 were residents in a control district of the same Rayong province but without industrial exposures. The groups of workers were analyzed separately to evaluate if DNA adduct formation differs by the type of industry. The levels of bulky DNA adducts were 1.17+/-0.17 (SE) adducts/10(8) nucleotides in refinery workers, 1.19+/-0.19 (SE) in steel workers, 0.87+/-0.17 (SE) in tinplate workers, 0.85+/-0.07 (SE) in MIE residents and 0.53+/-0.05 (SE) in district controls. No effects of smoking habits on DNA adducts was found. The multivariate regression analysis shows that the levels of DNA adducts were significantly increased among the individuals living near the MIE industrial complex in respect to those resident in a control district (p<0.05). In the groups of occupationally exposed workers, the highest levels of DNA adducts were found among the workers experiencing an occupational exposure to polycyclic aromatic hydrocarbons, e.g. the steel factory and refinery workers. When we have evaluated if the levels of DNA adducts of the PAH exposed workers were different from those of the MIE residents, a statistical significantly difference was found (p<0.05). Our present study indicates that people living near point sources of industrial air pollution can

  18. New isocyanate-specific albumin adducts of 4,4'-methylenediphenyl diisocyanate (MDI) in rats.

    PubMed

    Kumar, Anoop; Dongari, Nagaraju; Sabbioni, Gabriele

    2009-12-01

    4,4'-Methylenediphenyl diisocyanate (MDI) is the most important of the isocyanates used as intermediates in the chemical industry. Among the main types of damage after exposure to low levels of MDI are lung sensitization and asthma. Albumin adducts of MDI might be involved in the etiology of sensitization reactions. It is, therefore, necessary to have sensitive and specific methods for monitoring the isocyanate exposure of workers. To date, urinary metabolites or protein adducts have been used as biomarkers in workers exposed to MDI. However, with these methods it is not possible to determine whether the biomarkers result from exposure to MDI or to the parent aromatic amine 4,4'-methylenedianiline (MDA). This work presents a procedure for the determination of isocyanate-specific albumin adducts. In a long-term experiment, designed to determine the carcinogenic and toxic effects of MDI, rats were exposed chronically for 3 months, to 0.0 (control), 0.26, 0.70, and 2.06 mg MDI/m(3) as aerosols. Albumin was isolated from plasma, digested with Pronase E, and analyzed by LC-MS/MS. MDI formed adducts with lysine: N(6)-[({4-[4-aminobenzyl]phenyl}amino)carbonyl]lysine (MDI-Lys) and N(6)-[({4-[4-(acetylamino)benzyl]phenyl}amino)carbonyl] lysine (AcMDI-Lys). For the quantitation of the adducts in vivo, isotope dilution mass spectrometry was used to measure the adducts in 2 mg of albumin. The adducts found in vivo (MDI-Lys and AcMDI-Lys) and the corresponding isotope labeled compounds (MDI-[(13)C(6)(15)N(2)]Lys and Ac[(2)H(4)]MDI-Lys) were synthesized and used for quantitation. The MDI-Lys levels increased from 0-24.8 pmol/mg albumin, and the AcMDI-Lys levels increased from 0-1.85 pmol/mg albumin. The mean ratio of MDI-Lys/AcMDI-Lys for each dose level was greater than >20. The albumin adducts correlate with other biomarkers measured in the same rats in the past: urinary metabolites and hemoglobin adducts released after mild base hydrolysis. This method will enable one to

  19. Bilateral failure of adduction following orbital decompression.

    PubMed Central

    Kinsella, F; Kyle, P; Stansfield, A

    1990-01-01

    We report a case of bilateral complete failure of adduction following bilateral translid antralethmoidal orbital decompression. We believe the probable mechanism is neuropraxia (temporary dysfunction) of the third cranial nerves' supply to the medial recti, owing to these nerves' occupying an anatomically abnormal position. Partial recovery of adduction occurred over the ensuing six months. Images PMID:2337551

  20. Aromatic graphene

    SciTech Connect

    Das, D. K.; Sahoo, S.

    2016-04-13

    In recent years graphene attracts the scientific and engineering communities due to its outstanding electronic, thermal, mechanical and optical properties and many potential applications. Recently, Popov et al. [1] have studied the properties of graphene and proved that it is aromatic but without fragrance. In this paper, we present a theory to prepare graphene with fragrance. This can be used as scented pencils, perfumes, room and car fresheners, cosmetics and many other useful household substances.

  1. Aromatic graphene

    NASA Astrophysics Data System (ADS)

    Das, D. K.; Sahoo, S.

    2016-04-01

    In recent years graphene attracts the scientific and engineering communities due to its outstanding electronic, thermal, mechanical and optical properties and many potential applications. Recently, Popov et al. [1] have studied the properties of graphene and proved that it is aromatic but without fragrance. In this paper, we present a theory to prepare graphene with fragrance. This can be used as scented pencils, perfumes, room and car fresheners, cosmetics and many other useful household substances.

  2. PRACTICAL SYNTHESIS OF AROMATIC DITHIOCARBAMATES

    PubMed Central

    Padungros, Panuwat; Wei, Alexander

    2015-01-01

    GRAPHICAL ABSTRACT Oxidation-sensitive N,N-diaryl dithiocarbamates (DTCs) are synthesized in good yields by the generation of metal amide salts from N-benzoyl precursors, followed by addition of CS2. para-Substituted diphenylamines are prepared by electrophilic aromatic substitution of diphenylbenzamide and saponification. Deacylation of electron-rich species such as bis(p-dimethylaminophenyl)benzamide is challenging because of the oxidative sensitivity of the anionic intermediate but could be achieved in good yield by using n-BuLi to generate a hemiaminal adduct, prior to acidification. The N,N-diaryl DTCs are stable as alkali salts and can be used to produce densely packed monolayers on gold surfaces. PMID:25999616

  3. Role of CYP1B1 in PAH-DNA adduct formation and breast cancer risk

    SciTech Connect

    Goth-Goldstein, Regine; Russell, Marion L.; Muller, A.P.; Caleffi, M.; Eschiletti, J.; Graudenz, M.; Sohn, Michael D.

    2010-04-01

    This study investigated the hypothesis that increased exposure to polycyclic aromatic hydrocarbons (PAHs) increases breast cancer risk. PAHs are products of incomplete burning of organic matter and are present in cigarette smoke, ambient air, drinking water, and diet. PAHs require metabolic transformation to bind to DNA, causing DNA adducts, which can lead to mutations and are thought to be an important pre-cancer marker. In breast tissue, PAHs appear to be metabolized to their cancer-causing form primarily by the cytochrome P450 enzyme CYP1B1. Because the genotoxic impact of PAH depends on their metabolism, we hypothesized that high CYP1B1 enzyme levels result in increased formation of PAH-DNA adducts in breast tissue, leading to increased development of breast cancer. We have investigated molecular mechanisms of the relationship between PAH exposure, CYP1B1 expression and breast cancer risk in a clinic-based case-control study. We collected histologically normal breast tissue from 56 women (43 cases and 13 controls) undergoing breast surgery and analyzed these specimens for CYP1B1 genotype, PAH-DNA adducts and CYP1B1 gene expression. We did not detect any difference in aromatic DNA adduct levels of cases and controls, only between smokers and non-smokers. CYP1B1 transcript levels were slightly lower in controls than cases, but the difference was not statistically significant. We found no correlation between the levels of CYP1B1 expression and DNA adducts. If CYP1B1 has any role in breast cancer etiology it might be through its metabolism of estrogen rather than its metabolism of PAHs. However, due to the lack of statistical power these results should be interpreted with caution.

  4. Tumors and DNA adducts in mice exposed to benzo[a]pyrene and coal tars: implications for risk assessment.

    PubMed Central

    Goldstein, L S; Weyand, E H; Safe, S; Steinberg, M; Culp, S J; Gaylor, D W; Beland, F A; Rodriguez, L V

    1998-01-01

    Current methods to estimate the quantitative cancer risk of complex mixtures of polycyclic aromatic hydrocarbons (PAH) such as coal tar assume that overall potency can be derived from knowledge of the concentration of a few carcinogenic components such as benzo[a]pyrene (B[a]P). Genotoxic damage, such as DNA adducts, is thought to be an essential aspect of PAH-induced tumorigenesis and could be a biomarker for exposure useful for estimating risk. However, the role of B[a]P and the relationship of adduct formation in tumorigenesis have not been tested rigorously in models appropriate for human health risk assessment. Therefore, we directly compared tumor induction and adduct formation by B[a]P and coal tars in several experimental protocols, including one broadly accepted and used by regulators. We found that B[a]P content did not account for tumor incidences after exposure to coal tars. DNA adducts were found in both tumors and tumor-free tissue and tumor outcomes were not predicted by either quantitation of total DNA adducts or by the DNA adduct formed by B[a]P. These data suggest that risk assessments based on B[a]P content may not predict accurately risk to human health posed by environmental PAH. PMID:9860888

  5. Metabolic polymorphisms and carcinogen-DNA adduct formation in human populations.

    PubMed

    Kaderlik, K R; Kadlubar, F F

    1995-01-01

    Metabolic polymorphisms have long been recognized as important determinants of carcinogen susceptibility and recent efforts have shown that interindividual differences in specific cytochromes P450, acetyltransferases, sulfotransferases and glutathione S-transferases are often disproportionately represented in epidemiological studies between cancer cases and controls. Concomitantly, biomonitoring of carcinogen-DNA adducts in human tissues using immunochemical, 32P-postlabelling, fluorescence, and mass spectrometric methods have recently provided direct evidence of human exposure to genotoxic aromatic and heterocyclic amines, polycyclic hydrocarbons, alkylating agents, and endogenous products. However, a combined approach is now needed in order to assess the relevance of these findings to cancer etiology, to identify high-risk individuals, and to provide better health monitoring, earlier diagnosis, and cancer prevention. Using this paradigm, results are presented that implicate specific aromatic amines, heterocyclic amines, and polycyclic aromatic hydrocarbons in the etiology of human urinary bladder, colon, and laryngeal cancers.

  6. Metabolism and Biomarkers of Heterocyclic Aromatic Amines in Molecular Epidemiology Studies: Lessons Learned from Aromatic Amines

    PubMed Central

    2011-01-01

    Aromatic amines and heterocyclic aromatic amines (HAAs) are structurally related classes of carcinogens that are formed during the combustion of tobacco or during the high-temperature cooking of meats. Both classes of procarcinogens undergo metabolic activation by N-hydroxylation of the exocyclic amine group, to produce a common proposed intermediate, the arylnitrenium ion, which is the critical metabolite implicated in toxicity and DNA damage. However, the biochemistry and chemical properties of these compounds are distinct and different biomarkers of aromatic amines and HAAs have been developed for human biomonitoring studies. Hemoglobin adducts have been extensively used as biomarkers to monitor occupational and environmental exposures to a number of aromatic amines; however, HAAs do not form hemoglobin adducts at appreciable levels and other biomarkers have been sought. A number of epidemiologic studies that have investigated dietary consumption of well-done meat in relation to various tumor sites reported a positive association between cancer risk and well-done meat consumption, although some studies have shown no associations between well-done meat and cancer risk. A major limiting factor in most epidemiological studies is the uncertainty in quantitative estimates of chronic exposure to HAAs and, thus, the association of HAAs formed in cooked meat and cancer risk has been difficult to establish. There is a critical need to establish long-term biomarkers of HAAs that can be implemented in molecular epidemioIogy studies. In this review article, we highlight and contrast the biochemistry of several prototypical carcinogenic aromatic amines and HAAs to which humans are chronically exposed. The biochemical properties and the impact of polymorphisms of the major xenobiotic-metabolizing enzymes on the biological effects of these chemicals are examined. Lastly, the analytical approaches that have been successfully employed to biomonitor aromatic amines and HAAs, and

  7. CYP1A2 and NAT2 phenotyping and 3-aminobiphenyl and 4-aminobiphenyl hemoglobin adduct levels in smokers and non-smokers

    SciTech Connect

    Sarkar, Mohamadi; Stabbert, Regina; Kinser, Robin D.; Oey, Jan; Rustemeier, Klaus; Holt, Klaus von; Schepers, Georg; Walk, Roger A.; Roethig, Hans J.

    2006-06-15

    Some aromatic amines are considered to be putative bladder carcinogens. Hemoglobin (Hb) adducts of 3-aminobiphenyl (3-ABP) and 4-aminobiphenyl (4-ABP) have been used as biomarkers of exposure to aromatic amines from cigarette smoke. One of the goals of this study was to determine intra- and inter-individual variability in 3-ABP and 4-ABP Hb adducts and to explore the predictability of ABP Hb adduct levels based on caffeine phenotyping. The study was conducted in adult smokers (S, n = 65) and non-smokers (NS, n 65). The subjects were phenotyped for CYP1A2 and NAT2 using urinary caffeine metabolites. Blood samples were collected twice within 6 weeks and adducts measured by GC/MS. The levels of 4-ABP Hb adducts were significantly (p < 0.0001) greater in S (34.5 {+-} 21.06 pg/g Hb) compared to NS (6.3 {+-} 3.02 pg/g Hb). The levels of 3-ABP Hb adducts were below the limit of quantification (BLOQ) in most (82%) of the NS and about 10-fold lower in S (3.6 {+-} 3.29 pg/g Hb) compared to 4-ABP Hb adducts. No differences were observed in the adduct levels between weeks 1 and 6 in the smokers, suggesting that a single sample would be adequate to monitor cigarette smoke exposure. The regression model developed with CYP1A2, NAT2 phenotype and number of cigarettes smoked (NCIG) accounted for 47% of the variability in 3-ABP adducts, whereas 32% variability in 4-ABP adducts was accounted by CYP1A2 and NCIG. The ratio of 4-ABP Hb adducts in adult S:NS was {approx} 5:1, whereas 3-ABP Hb adducts levels were BLOQ in some S, exhibited large interindividual variability ({approx} 91% compared to 57% for 4-ABP Hb) and poor dose response relationship. Therefore, 4-ABP Hb adduct levels may be a more useful biomarker of aminobiphenyl exposure from cigarette smoke.

  8. B(a)P adduct levels and fertility: A cross‑sectional study in a Sicilian population.

    PubMed

    Oliveri Conti, Gea; Calogero, Aldo Eugenio; Giacone, Filippo; Fiore, Maria; Barchitta, Martina; Agodi, Antonella; Ferrante, Margherita

    2017-05-01

    Benzo(a)pyrene (BaP) is a carcinogenic polycyclic aromatic hydrocarbon for human tissues. Still today it is not fully investigated if BaP can affect negatively the male fertility through the BaP‑DNA adducts production. In the present study, BaP Tetrol I‑1 (TI‑1) and BaP Tetrol II‑2 (TII‑2) BaP‑DNA adducts were investigated in spermatozoa of a Sicilian male population. Semen samples from 86 volunteers in two eastern Sicilian cities (Regalbuto and Melilli) were collected. The quality of semen was evaluated in all samples according to the World Health Organization (WHO) guidelines. We analyzed BaP‑DNA adducts in extracted sperm cell DNA using the modified high‑performance liquid chromatography‑fluorescence method to detects both Tetrols. Differences between Tetrol levels were assessed by the Wilcoxon signed‑rank test and the Mann‑Whitney U test, as appropriate. Correlation between semen quality parameters and Tetrol concentrations were analyzed using the Spearman's correlation coefficient. Σ(TI‑1+TII‑2) were significantly higher in spermatozoa of volunteers from Regalbuto. Furthermore, a greater dispersion of the levels of adducts was observed in these specimens. TI‑1 adducts were higher than TII‑2 in Melilli samples (95% CI) and TII‑2 were higher than TI‑1 in Regalbuto semen samples (95% CI). A significant inverse correlation between sperm progressive motility and both TI‑1 and TII‑2 adducts was observed. The present study showed that BaP negatively affects male fertility by TI‑1 and TII‑2 DNA‑adduct production. These results suggest that DNA adducts could be used as biomarker to assess BaP exposure by air pollution. Further studies are needed to confirm if these findings could affect male fertility because of the growing impairment of this function observed in recent years.

  9. B(a)P adduct levels and fertility: A cross-sectional study in a Sicilian population

    PubMed Central

    Conti, Gea Oliveri; Calogero, Aldo Eugenio; Giacone, Filippo; Fiore, Maria; Barchitta, Martina; Agodi, Antonella; Ferrante, Margherita

    2017-01-01

    Benzo(a)pyrene (BaP) is a carcinogenic polycyclic aromatic hydrocarbon for human tissues. Still today it is not fully investigated if BaP can affect negatively the male fertility through the BaP-DNA adducts production. In the present study, BaP Tetrol I-1 (TI-1) and BaP Tetrol II-2 (TII-2) BaP-DNA adducts were investigated in spermatozoa of a Sicilian male population. Semen samples from 86 volunteers in two eastern Sicilian cities (Regalbuto and Melilli) were collected. The quality of semen was evaluated in all samples according to the World Health Organization (WHO) guidelines. We analyzed BaP-DNA adducts in extracted sperm cell DNA using the modified high-performance liquid chromatography-fluorescence method to detects both Tetrols. Differences between Tetrol levels were assessed by the Wilcoxon signed-rank test and the Mann-Whitney U test, as appropriate. Correlation between semen quality parameters and Tetrol concentrations were analyzed using the Spearman's correlation coefficient. Σ(TI-1+TII-2) were significantly higher in spermatozoa of volunteers from Regalbuto. Furthermore, a greater dispersion of the levels of adducts was observed in these specimens. TI-1 adducts were higher than TII-2 in Melilli samples (95% CI) and TII-2 were higher than TI-1 in Regalbuto semen samples (95% CI). A significant inverse correlation between sperm progressive motility and both TI-1 and TII-2 adducts was observed. The present study showed that BaP negatively affects male fertility by TI-1 and TII-2 DNA-adduct production. These results suggest that DNA adducts could be used as biomarker to assess BaP exposure by air pollution. Further studies are needed to confirm if these findings could affect male fertility because of the growing impairment of this function observed in recent years. PMID:28350051

  10. Significant positive correlation of plasma BPDE-albumin adducts to urinary 1-hydroxypyrene in coke oven workers.

    PubMed

    Wang, Hong; Yang, Xiao-Bo; Liu, Ai-Lin; Zhen, Hong-Yan; Guo, Liang; Liang, Hua-Shan; Bi, Yong-Yi; Bai, Yun; Chen, Yong-Wen; Wu, Tang-Chun

    2007-06-01

    To investigate the application of BPDE-albumin adducts as monitoring biomarkers for coke oven workers exposed to polycyclic aromatic hydrocarbons (PAHs) and to explore possible relationship between BPDE-albumin adducts and urinary 1-hydroxypyrene (1-OHP) levels in them. Thirty-seven coke oven workers from a coke plant and 47 controls without the occupational exposure to PAHs were recruited in this study. The levels of plasma BPDE-albumin adducts and urinary 1-OHP were analyzed using high performance liquid chromatography. The median levels of BPDE-albumin adducts (42.10 fmol/mg albumin) and urinary 1-OHP (5.46 micromol/mol creatinine) were significantly higher in coke oven workers than in controls (14.16 fmol/mg albumin, 2.96 micromol/mol creatinine, respectively; P<0.01). Multiple logistic regression analysis showed that coke oven workers were at higher risk of having BPDE-albumin adduct levels above 25.30 micromol/mg albumin (OR=1.79, P<0.01) and urinary 1-OHP levels above 4.13 micromol/mol creatinine (OR=2.45, P<0.05). There was a positive correlation between the levels of BPDE-albumin adducts and urinary 1-OHP in all subjects (rs=0.349, P<0.01). BPDE-albumin adduct is a useful biomarker for monitoring long-term exposure to PAHs, and plasma BPDE-albumin adducts level is significantly correlated to urinary 1-OHP levels in coke oven workers.

  11. Use of carcinogen-DNA adduct antisera for quantitation and localization of genomic damage in animal models and the human population

    SciTech Connect

    Poirier, M.C.

    1984-01-01

    The use of antibodies to detect chemical carcinogen-induced DNA damage involves quantitative determination and morphological localization utilizing antisera specific for carcinogen-DNA adducts. In recent years a large number of polyclonal and monoclonal antisera have been produced against individual adducts, and modified DNAs with addition products varying in structure from ethyl and methyl groups to aromatic amines, polycyclic aromatic hydrocarbons, aflatoxins, and platinum-ammine complexes. This review focuses on data generated during the past 3 yr utilizing this immunotechnology as a tool to probe mechanisms of carcinogen-DNA interactions in various model systems and in the human population. Areas discussed in depth include quantitative and morphological studies involving detection of 2-acetylaminofluorene-DNA adducts in rat liver, O/sup 6/-ethyl and O/sup 6/-methyl deoxyguanosine adducts in rat brain, benzo(a)pyrene-DNA adducts in mouse skin and cis-diamminedichloroplatinum (II)-DNA adducts in peripheral nucleated blood cells of cancer patients.

  12. Coal tar residues produce both DNA adducts and oxidative DNA damage in human mammary epithelial cells.

    PubMed

    Leadon, S A; Sumerel, J; Minton, T A; Tischler, A

    1995-12-01

    In the present study we compare the metabolic activation of coal tar, as measured by the production of both DNA adducts and oxidative DNA damage, with that of a single carcinogen that is a constituent of this complex mixture in human mammary epithelial cells (HMEC). We find that a significant level of DNA adducts, detected by 32P-postlabeling, are formed in HMEC following exposure to coal tar residues. This treatment also results in the generation of high levels of oxidative DNA damage, as measured by the production of one type of oxidative base modification, thymine glycols. The amounts of both DNA adducts and thymine varied considerably between the various coal tar residues and did not correlate with either the total amount of polycyclic aromatic hydrocarbons (PAH) or the amount of benzo[a]pyrene (B[a]P) present in the residue. Fractionating the residue from one of the sites by sequential extraction with organic solvents indicated that while the ability to produce both types of DNA damage was contained mostly in a hexane-soluble fraction, a benzene-soluble fraction produced high levels of reactive oxygens relative to the number of total DNA adducts. We find that the total amount of PAH or B[a]P present in the coal tars from the various sites was not a predictor of the level of total DNA damage formed.

  13. MALDI-TOF analysis of steroid/PAH-modified DNA adducts at the femtomole level

    SciTech Connect

    Gooden, J.K.; Gross, M.L.; Stack, D.

    1995-12-31

    Covalent binding of polycyclic aromatic hydrocarbons (PAH`s) and steroids to DNA to form adducts is one of the first events in the process of tumor initiation in carcinogenesis. Structure elucidation and characterization of these adducts provide important information that leads to further understanding of their biological metabolic pathways. In in vivo and in vitro steroid/PAH-DNA binding studies, the reaction products (adducts) are often of low amount (low picomole to femtomole). Previous results from this laboratory have shown that the sensitivity of MALDI-TOF can be improved by proper matrix selection. An increase in sensitivity can also be obtained with the use of d-fucose as a co-matrix. In this study 4-phenyl-{alpha}-cyanocinnamic acid, PCC, 4-benzyloxy-{alpha}-cyanocinnamic acid, BCC, ferulic acid, FA, {alpha}-cyano-4-hydroxycinnamic acid, 4HCCA, and 3-(2-naphthyl)-2-cyanoacrylic NCA, were used in the determination of the limit of detection for two different DNA adducts dibenzocarbazole-5-N7Ade, and 4-hydroxyestrone-N7Gua.

  14. Cytotoxic and mutagenic effects of specific carcinogen-DNA adducts in diploid human fibroblasts

    SciTech Connect

    McCormick, J.J.; Maher, V.M.

    1985-10-01

    A comparison of the cytotoxicity and mutagenicity of a series of carcinogens in normal diploid human fibroblasts and in cells deficient in one or more DNA repair processes has provided insight into the specific DNA adduct(s) responsible for these biological effects. The carcinogens tested include ultraviolet radiation; reactive derivatives of structurally related aromatic amides; metabolites of benzo(a)pyrene; the simple alkylating agents N-methyl-N'-nitro-N-nitrosoguanidine and N-ethyl-N-nitrosourea; and aflatoxin B/sub 1/ dichloride, a model for the reactive 2,3-epoxide of aflatoxin B/sub 1/. Exponentially growing cells were exposed to agents and assayed for mutations and cell killing. Cells deficient in repair of particular DNA adducts or lesions proved more sensitive to the agent causing those lesions than did normally repairing cells. Many of the carcinogens were compared for their mutagenic and/or cytotoxic effect, not only as a function of dose administered, but also as a function of the initial number of adducts or photoproducts induced in DNA and the number remaining at critical times posttreatment. The results demonstrated a high correlation between the number of DNA lesions remaining unexcised at the time the DNA was replicated and frequency of mutations induced. Comparative studies of the frequency of UV-induced transformation of normal and repair-deficient cells showed this also to be true for transformation.

  15. Characterization of isomeric VX nerve agent adducts on albumin in human plasma using liquid chromatography-tandem mass spectrometry.

    PubMed

    Saeidian, Hamid; Mirkhani, Valioallah; Mousavi Faraz, Sajjad; Taghi Naseri, Mohammad; Babri, Mehran

    2015-01-01

    This study includes the characterization of isomeric VX organophosphorus adducts on albumin in human plasma using liquid chromatography-tandem mass spectrometry (LC-MS/MS). VX or its structural isomers were spiked into a vial containing plasma in order to obtain phosphorylated albumin. After pronase and trypsin digestion, the resulting solutions were analyzed to confirm adduct formation with the amino acid tyrosine on the albumin in human plasma. The LC-MS/MS experiments show that VX and its isomers can be attached to tyrosine on the albumin in human blood. Mass spectrometric studies revealed some interesting fragmentation pathways during the ionization process, such as ethylene, formic acid and ammonia elimination and an intermolecular electrophilic aromatic substitution reaction. The proposed mechanisms for the formation of the fragments were confirmed through the analysis of fragments of deuterated adducts.

  16. INDUCTION OF DNA ADDUCTS, TUMORS, AND KI-RAS ONCOGENE MUTATIONS IN STRAIN A/J MOUSE LUNG BY IP. ADMINISTRATION OF DIBENZ[A,H]ANTHRACENE

    EPA Science Inventory

    Induction of DNA adducts, tumors, and Ki-ras oncogene mutations in strain AlJ mouse lung by ip. administration of dibenz[a,h]anthracene

    Previous studies of polycyclic aromatic hydrocarbon (P AH) induced lung tumors in the strain NJ mouse model system have demonstrated qua...

  17. MUTATIONS INDUCED BY BENZO[ A ]PYRENE AND DIBENZO[ A,L ]PYRENE IN LACI TRANSGENIC B6C3F1 MOUSE LUNG RESULT FROM STABLE DNA ADDUCTS

    EPA Science Inventory

    Dibenzo[a,l]pyrene (DB[a,l]P) and benzo[a]pyrene (B[a]P) are carcinogenic polycyclic aromatic hydrocarbons (PAH) that are each capable of forming a variety of covalent adducts with DNA, some of which spontaneously depurinate, producing apurinic (AP) si...

  18. AN EVALUATION OF THE MUTAGENICITY, METABOLISM AND DNA ADDUCT FORMATION OF 5-NITROBENZO[B]NAPHTHO[2,1-D]THIOPHENE

    EPA Science Inventory

    An Evaluation of the Mutagenicity, Metabolism and DNA Adduct Formation of 5-Nitrobenzo[b ]naphtho[2, I-d]thiophene

    Thioarenes, sulfur containing polycyclic aromatic compounds, are environmental contaminants suspected of posing human health risks. In this study, 5-nitroben...

  19. INDUCTION OF DNA ADDUCTS, TUMORS, AND KI-RAS ONCOGENE MUTATIONS IN STRAIN A/J MOUSE LUNG BY IP. ADMINISTRATION OF DIBENZ[A,H]ANTHRACENE

    EPA Science Inventory

    Induction of DNA adducts, tumors, and Ki-ras oncogene mutations in strain AlJ mouse lung by ip. administration of dibenz[a,h]anthracene

    Previous studies of polycyclic aromatic hydrocarbon (P AH) induced lung tumors in the strain NJ mouse model system have demonstrated qua...

  20. Association between Mutation Spectra and Stable and Unstable DNA Adduct Profiles in Salmonella for Benzo[a]pyrene and Dibenzo[a.l]pyrene

    EPA Science Inventory

    Benzo[a]pyrene (BP) and dibenzo[a,l]pyrene (DBP) are two polycyclic aromatic hydrocarbons (PAHs) that exhibit distinctly different mutagenicity and carcinogenicity profiles. Although some studies show that these PAHs produce unstable DNA adducts, conflicting data and arguments ha...

  1. MUTATIONS INDUCED BY BENZO[ A ]PYRENE AND DIBENZO[ A,L ]PYRENE IN LACI TRANSGENIC B6C3F1 MOUSE LUNG RESULT FROM STABLE DNA ADDUCTS

    EPA Science Inventory

    Dibenzo[a,l]pyrene (DB[a,l]P) and benzo[a]pyrene (B[a]P) are carcinogenic polycyclic aromatic hydrocarbons (PAH) that are each capable of forming a variety of covalent adducts with DNA, some of which spontaneously depurinate, producing apurinic (AP) si...

  2. Association between Mutation Spectra and Stable and Unstable DNA Adduct Profiles in Salmonella for Benzo[a]pyrene and Dibenzo[a.l]pyrene

    EPA Science Inventory

    Benzo[a]pyrene (BP) and dibenzo[a,l]pyrene (DBP) are two polycyclic aromatic hydrocarbons (PAHs) that exhibit distinctly different mutagenicity and carcinogenicity profiles. Although some studies show that these PAHs produce unstable DNA adducts, conflicting data and arguments ha...

  3. AN EVALUATION OF THE MUTAGENICITY, METABOLISM AND DNA ADDUCT FORMATION OF 5-NITROBENZO[B]NAPHTHO[2,1-D]THIOPHENE

    EPA Science Inventory

    An Evaluation of the Mutagenicity, Metabolism and DNA Adduct Formation of 5-Nitrobenzo[b ]naphtho[2, I-d]thiophene

    Thioarenes, sulfur containing polycyclic aromatic compounds, are environmental contaminants suspected of posing human health risks. In this study, 5-nitroben...

  4. Detection of DNA adducts by bioluminescence

    NASA Astrophysics Data System (ADS)

    Xu, Shunqing; Tan, Xianglin; Yao, Qunfeng; He, Min; Zhou, Yikai; Chen, Jian

    2001-09-01

    Luminescent assay for detection ATP is very sensitive with limitation of 10-17 moles. ATP using styrene oxide as a model carcinogen we currently apply a luminescence technique to detect the very low levels of carcinogen-DNA adducts in vitro and in vivo. The bioluminescent assay of DNA adducts entails three consecutive steps: digestion of modified DNA to adducted dinucleoside monophosphate and normal nucleotide are hydrolyzed to nucleosides (N) by nuclease P1 and prostatic acid phosphomonesterase (PAP); incorporation of (gamma) -P of ATP into normal nucleoside(N); detection of consumption of ATP by luminescence. This assay does not require separate manipulation because of the selective property of nuclease P1. One fmol of carcinogen- DNA adducts was detected by luminescent assay. A good correlation between results of luminescent assay and 32P-postlabeling procedures has been observed. We detect 1 adduct in 108 nucleotides for 10(mu) g DNA sample. The procedures of luminescent method is very simple and low- cost. IT appears applicable to the ultra sensitive detection of low levels of DNA adducts without radioactive isotope.

  5. Variation in PAH-related DNA adduct levels among non-smokers: the role of multiple genetic polymorphisms and nucleotide excision repair phenotype

    PubMed Central

    Etemadi, Arash; Islami, Farhad; Phillips, David H.; Godschalk, Roger; Golozar, Asieh; Kamangar, Farin; Malekshah, Akbar Fazel-Tabar; Pourshams, Akram; Elahi, Seerat; Ghojaghi, Farhad; Strickland, Paul T; Taylor, Philip R; Boffetta, Paolo; Abnet, Christian C; Dawsey, Sanford M; Malekzadeh, Reza; van Schooten, Frederik J.

    2012-01-01

    Polycyclic aromatic hydrocarbons (PAHs) likely play a role in many cancers even in never-smokers. We tried to find a model to explain the relationship between variation in PAH-related DNA adduct levels among people with similar exposures, multiple genetic polymorphisms in genes related to metabolic and repair pathways, and nucleotide excision repair (NER) capacity. In 111 randomly-selected female never-smokers from the Golestan Cohort Study in Iran, we evaluated 21 SNPs in 14 genes related to xenobiotic metabolism and 12 SNPs in 8 DNA repair genes. NER capacity was evaluated by a modified comet assay, and aromatic DNA adduct levels were measured in blood by 32P-postlabelling. Multivariable regression models were compared by Akaike’s information criterion (AIC). Aromatic DNA adduct levels ranged between 1.7 and 18.6 per 108 nucleotides (mean: 5.8±3.1). DNA adduct level was significantly lower in homozygotes for NAT2 slow alleles and ERCC5 non risk-allele genotype, and was higher in the MPO homozygote risk-allele genotype. The sum of risk alleles in these genes significantly correlated with the log-adduct level (r=0.4, p<0.001). Compared with the environmental model, adding phase I SNPs and NER capacity provided the best fit, and could explain 17% more of the variation in adduct levels. NER capacity was affected by polymorphisms in the MTHFR and ERCC1 genes. Female non-smokers in this population had PAH-related DNA adduct levels 3-4 times higher than smokers and occupationally-exposed groups in previous studies, with large inter-individual variation which could best be explained by a combination of phase I genes and NER capacity. PMID:23175176

  6. Identification of Carcinogen DNA Adducts in Human Saliva by Linear Quadrupole Ion Trap/Multistage Tandem Mass Spectrometry

    PubMed Central

    Bessette, Erin E.; Spivack, Simon D.; Goodenough, Angela K.; Wang, Tao; Pinto, Shailesh; Kadlubar, Fred F.; Turesky, Robert J.

    2010-01-01

    DNA adducts of carcinogens derived from tobacco smoke and cooked meat were identified, by liquid chromatography-electrospray ionization/multi-stage tandem mass spectrometry (LC-ESI/MS/MSn), in saliva samples from 37 human volunteers on unrestricted diets. The N-(deoxyguanosin-8-yl) (dG-C8) adducts of the heterocyclic aromatic amines 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP); 2-amino-9H-pyrido[2,3-b]indole (AαC); 2-amino-3,8-dimethylmidazo[4,5-f]quinoxaline (MeIQx); and the aromatic amine, 4-aminobiphenyl (4-ABP) were characterized and quantified, by LC-ESI/MS/MSn, employing consecutive reaction monitoring at the MS3 scan stage mode with a linear quadrupole ion trap (LIT) mass spectrometer (MS). DNA adducts of PhIP were found most frequently: dG-C8-PhIP was detected in saliva samples from 13 of 29 ever-smokers and in saliva samples from 2 of 8 never-smokers. dG-C8-AαC and dG-C8-MeIQx were identified solely in saliva samples of 3 current smokers, and dG-C8-4-ABP was detected in saliva from 2 current-smokers. The levels of these different adducts ranged from 1 to 9 adducts per 108 DNA bases. These findings demonstrate that PhIP is a significant DNA-damaging agent in humans. Saliva appears to be a promising biological fluid in which to assay DNA adducts of tobacco and dietary carcinogens, by selective LIT MS techniques. PMID:20443584

  7. Identification of carcinogen DNA adducts in human saliva by linear quadrupole ion trap/multistage tandem mass spectrometry.

    PubMed

    Bessette, Erin E; Spivack, Simon D; Goodenough, Angela K; Wang, Tao; Pinto, Shailesh; Kadlubar, Fred F; Turesky, Robert J

    2010-07-19

    DNA adducts of carcinogens derived from tobacco smoke and cooked meat were identified by liquid chromatography-electrospray ionization/multistage tandem mass spectrometry (LC-ESI/MS/MS(n)) in saliva samples from 37 human volunteers on unrestricted diets. The N-(deoxyguanosin-8-yl) (dG-C8) adducts of the heterocyclic aromatic amines 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), 2-amino-9H-pyrido[2,3-b]indole (AalphaC), 2-amino-3,8-dimethylmidazo[4,5-f]quinoxaline (MeIQx), and the aromatic amine, 4-aminobiphenyl (4-ABP), were characterized and quantified by LC-ESI/MS/MS(n), employing consecutive reaction monitoring at the MS(3) scan stage mode with a linear quadrupole ion trap (LIT) mass spectrometer (MS). DNA adducts of PhIP were found most frequently: dG-C8-PhIP was detected in saliva samples from 13 of 29 ever-smokers and in saliva samples from 2 of 8 never-smokers. dG-C8-AalphaC and dG-C8-MeIQx were identified solely in saliva samples of three current smokers, and dG-C8-4-ABP was detected in saliva from two current smokers. The levels of these different adducts ranged from 1 to 9 adducts per 10(8) DNA bases. These findings demonstrate that PhIP is a significant DNA-damaging agent in humans. Saliva appears to be a promising biological fluid in which to assay DNA adducts of tobacco and dietary carcinogens by selective LIT MS techniques.

  8. New methods for the synthesis of aromatic fluorine compounds from industrial freons and polyfluorinated olefins

    SciTech Connect

    Nefedov, O.M.; Volchkov, N.V.

    1995-01-10

    The results from investigations into the development and application of a strategy and new methods for the synthesis of aromatic fluorine compounds, using fluorohalogenomethanes and polyfluorinated olefins as initial fluorine-containing substrates or structural units, are summarized. Two general methods for the production of fluoroarenes, involving the synthetic assembly of fluorobenzenoid structures through the cycloaddition of fluorocarbenes and fluoroalkenes to various 1,3-diene substrates and subsequent aromatization of the obtained fluorinated cyclopropane, cyclobutane, or cyclohexene adducts, are examined.

  9. Synthesis, Identification, and Structure Elucidation of Adducts Formed by Reactions of Hydroxycinnamic Acids with Glutathione or Cysteinylglycine.

    PubMed

    Ferreira-Lima, Nayla; Vallverdú-Queralt, Anna; Meudec, Emmanuelle; Mazauric, Jean-Paul; Sommerer, Nicolas; Bordignon-Luiz, Marilde T; Cheynier, Véronique; Le Guernevé, Christine

    2016-09-23

    Grape polyphenols, especially hydroxycinnamic acids such as caftaric and caffeic acid, are prone to enzymatic oxidation reactions during the winemaking process, forming o-quinones and leading to color darkening. Glutathione is capable of trapping these o-quinones and thus limiting juice browning. In this study, the addition of glutathione or cysteinylglycine onto caftaric or caffeic acid o-quinones formed by polyphenoloxidase-catalyzed reactions was investigated by UPLC-DAD-ESIMS and NMR data analyses. Complete identification of adducts has been achieved via NMR data. The results confirmed that the favored reaction is the substitution of the sulfanyl group of cysteine at C-2 of the aromatic ring. Several minor isomers, namely, the cis-isomer of the 2-S adduct and trans-isomers of the 5-S and 6-S adducts, and the 2,5-di-S-glutathionyl adducts were also identified and quantified by qNMR. With the exception of 2-(S-glutathionyl)- and 2,5-di(S-glutathionyl)-trans-caftaric acid, these products had never been formally identified. In particular, the 5-S and 6-S derivatives are reported here for the first time. The first formal identification of 2-S cis-derivatives is also provided. Moreover, NMR and UPLC-DAD-ESIMS analysis showed that signature UV and MS spectra can serve as markers of the conformation and substitution position in the aromatic ring for each of the isomers.

  10. Identification of two N{sup 2}-deoxyguanosinyl DNA adducts upon nitroreduction of the environmental mutagen 1-nitropyrene

    SciTech Connect

    Herreno-Saenz, D.; Evans, F.E.; Beland, F.A.

    1995-03-01

    1-Nitropyrene, the most abundant nitro-polycyclic aromatic hydrocarbon in the environment, is a known mammalian and bacterial mutagen and a tumorigen in animals. Early studies on DNA adduct characterization for 1-nitropyrene identified N-(deoxyguanosin-8-yl)-1-aminopyrene as the major product from the modification of calf thymus DNA with N-hydroxy-1-aminopyrene, the activated metabolite from nitroreduction of 1-nitropyrene. In this paper, we report the identification of two N{sup 2}-deoxyguanosinyl adducts, in addition to N-(deoxyguanosin-8-yl)-1-aminopyrene, formed from the reaction of N-hydroxy-1-aminopyrene, prepared in situ, with calf thymus DNA. These DNA adducts were identified as 6-(deoxyguanosin-N{sup 2}-yl)-1-aminopyrene and 8-(deoxyguanosin-N{sup 2}-yl)-1-aminopyrene. The two N{sup 2}-deoxyguanosinyl adducts were also identified in an ascorbic acid-catalyzed activation of 1-nitropyrene and in the mammary gland of female Sprague-Dawley rats administered 1-nitropyrene. The DNA adducts were also formed when 1-nitropyrene was metabolized by xanthine oxidase in the presence of calf thymus DNA, and when 1-nitropyrene was activated by rat liver microsomes and cytosols, as well as from DNA isolated from Salmonella typhimurium suspension cultures incubated with 1-nitropyrene. 45 refs., 7 figs., 1 tab.

  11. Contributions of aryl hydrocarbon receptor genetic variants to the risk of glioma and PAH-DNA adducts.

    PubMed

    Gu, Aihua; Ji, Guixiang; Jiang, Tao; Lu, Ailin; You, Yongping; Liu, Ning; Luo, Chengzhang; Yan, Wei; Zhao, Peng

    2012-08-01

    The aryl hydrocarbon receptor (AHR) gene is involved in the response to polycyclic aromatic hydrocarbon (PAH) exposure. To investigate the hypothesis that the genetic variants in the AHR gene might be a causal genetic susceptibility to PAH-DNA adduct formation and glioma risk, we conducted a case-control study of 384 glioma cases and 384 cancer-free controls to explore the association between six common single-nucleotide polymorphisms of the AHR gene and glioma risk. Using PAH-DNA adducts as biomarkers, we then evaluated the association between PAH-DNA adduct levels and glioma risk based on a tissue microarray including 11 controls and 77 glioma patients. We further explored the contributions of the glioma risk-associated AHR polymorphisms to the levels of PAH-DNA adducts in glioma tissues based on 77 glioma patients. We found that PAH-DNA adduct staining existed in normal brain tissues and grades I-IV gliomas, and the staining intensity was significantly associated with the glioma grade. Two AHR polymorphisms (rs2066853 and rs2158041) demonstrated significant association with glioma risk. Intriguingly, we also found statistically significant associations between these two variants and PAH-DNA adduct levels in glioma tissue. These data suggest the contributions of AHR rs2066853 and rs2158041 to glioma risk and the PAH-DNA adduct levels, which shed new light on gene-environment interactions in the etiology of glioma. Further studies with a larger sample size and ethnically diverse populations are required to elucidate the potential biological mechanism for, as well as the impact of, the susceptibility to glioma due to genetic variants of AHR.

  12. DNA adducts and related biomarkers in populations exposed to environmental carcinogens

    PubMed Central

    Perera, Frederica; Brenner, Diane; Jeffrey, Alan; Mayer, Jack; Tang, Deliang; Warburton, Dorothy; Young, Tie-lan; Wazneh, Leila; Latriano, Louise; Motykiewicz, Grazyna; Grzybowska, Ewa; Chorazy, Mieczyslaw; Hemminki, Kari; Santella, Regina

    1992-01-01

    Prevention of environmentally related cancer will be enhanced by the availability of sensitive early warning systems and by improvements in quantitative assessment of human risks. Accordingly, we have carried out a series of molecular epidemiologic studies aimed at validating a panel of biologic markers, including carcinogen–DNA and –protein adducts, sister chromatid exchange, micronucleus formation, DNA strand breaks, and DNA repair capacity. Results from three such studies illustrate the usefulness of these biomarkers in elucidating low-dose–response relationships, correlations between biomarkers, and the range of variation in biomarkers between individuals exposed to similar concentrations of carcinogens. Low-level workplace or ambient exposures to styrene, ethylene oxide, and polycyclic aromatic hydrocarbons (PAH) were associated with significant increases in both molecular dose of carcinogens (adducts) and various markers of preclinical effects. Correlations between biomarkers varied by exposure. For example, in the styrene study, sister chromatid exchange frequency was not correlated with any of the markers, in contrast to the studies of ethylene oxide and PAH. Significant molecular effects were observed not only in occupationally exposed people but also in residents of an area in Poland characterized by high levels of air pollution. For example, the mean PAH–DNA level in exposed residents (winter sample) was 30.4 adducts per 108 nucleotides. This level was significantly higher than that of adducts seen in summer samples from the same area (4.2/108), or in winter samples from residents of a rural area (11.01/108). Significant seasonal variation in PAH–DNA adduct formation in this group was consistent with recorded fluctuations in air pollution levels. Striking interindividual variation was observed in all three exposed populations. PMID:1486841

  13. Covalent adduct formation between the plasmalogen-derived modification product 2-chlorohexadecanal and phloretin

    PubMed Central

    Üllen, Andreas; Nusshold, Christoph; Glasnov, Toma; Saf, Robert; Cantillo, David; Eibinger, Gerald; Reicher, Helga; Fauler, Günter; Bernhart, Eva; Hallstrom, Seth; Kogelnik, Nora; Zangger, Klaus; Oliver Kappe, C.; Malle, Ernst; Sattler, Wolfgang

    2015-01-01

    Hypochlorous acid added as reagent or generated by the myeloperoxidase (MPO)-H2O2-Cl− system oxidatively modifies brain ether-phospholipids (plasmalogens). This reaction generates a sn2-acyl-lysophospholipid and chlorinated fatty aldehydes. 2-Chlorohexadecanal (2-ClHDA), a prototypic member of chlorinated long-chain fatty aldehydes, has potent neurotoxic potential by inflicting blood–brain barrier (BBB) damage. During earlier studies we could show that the dihydrochalcone-type polyphenol phloretin attenuated 2-ClHDA-induced BBB dysfunction. To clarify the underlying mechanism(s) we now investigated the possibility of covalent adduct formation between 2-ClHDA and phloretin. Coincubation of 2-ClHDA and phloretin in phosphatidylcholine liposomes revealed a half-life of 2-ClHDA of approx. 120 min, decaying at a rate of 5.9 × 10−3 min−1. NMR studies and enthalpy calculations suggested that 2-ClHDA-phloretin adduct formation occurs via electrophilic aromatic substitution followed by hemiacetal formation on the A-ring of phloretin. Adduct characterization by high-resolution mass spectroscopy confirmed these results. In contrast to 2-ClHDA, the covalent 2-ClHDA-phloretin adduct was without adverse effects on MTT reduction (an indicator for metabolic activity), cellular adenine nucleotide content, and barrier function of brain microvascular endothelial cells (BMVEC). Of note, 2-ClHDA-phloretin adduct formation was also observed in BMVEC cultures. Intraperitoneal application and subsequent GC–MS analysis of brain lipid extracts revealed that phloretin is able to penetrate the BBB of C57BL/6J mice. Data of the present study indicate that phloretin scavenges 2-ClHDA, thereby attenuating 2-ClHDA-mediated brain endothelial cell dysfunction. We here identify a detoxification pathway for a prototypic chlorinated fatty aldehyde (generated via the MPO axis) that compromises BBB function in vitro and in vivo. PMID:25576489

  14. PAH-DNA adducts in cord blood and fetal and child development in a Chinese cohort

    SciTech Connect

    Tang, D.L.; Li, T.Y.; Liu, J.J.; Chen, Y.H.; Qu, L.R.; Perera, F.

    2006-08-15

    Polycyclic aromatic hydrocarbons (PAHs) are an important class of toxic pollutants released by fossil fuel combustion. Other pollutants include metals and particulate matter. PAH-DNA adducts, or benzo(a)pyrene (BaP) adducts as their proxy, provide a chemical-specific measure of individual biologically effective doses that have been associated with increased risk of cancer and adverse birth outcomes. In the present study we examined the relationship between prenatal PAH exposure and fetal and child growth and development in Tongliang, China, where a seasonally operated coal-fired power plant was the major pollution source. In a cohort of 150 nonsmoking women and their newborns enrolled between 4 March 2002 and 19 June 2002, BaP-DNA adducts were measured in maternal and umbilical cord blood obtained at delivery. High PAH-DNA adduct levels (above the median of detectable adduct level) were associated with decreased birth head circumference (p = 0.057) and reduced children's weight at 18 months, 24 months, and 30 months of age (p {lt} 0.05), after controlling for potential confounders. In addition, in separate models, longer duration of prenatal exposure was associated with reduced birth length (p = 0.033) and reduced children's height at 18 (p = 0.001), 24 (p {lt} 0.001), and 30 months of age (p {lt} 0.001). The findings suggest that exposure to elevated levels of PAHS, with the Tongliang power plant being a significant source, is associated with reduced fetal and child growth in this population.

  15. Fragmentation patterns of DNA-benzo(a)pyrene diol epoxide adducts characterized by nanoflow LC/quadrupole time-of-flight mass spectrometry

    NASA Astrophysics Data System (ADS)

    Wang, Jin J.; Marshall, William D.; Law, Brandon; Lewis, Daniel M.

    2003-11-01

    Polycyclic aromatic hydrocarbons are a pervasive and abundant class of environmental and workplace pollutants. Formation of covalent DNA adducts has been considered to be a useful dosimeter or molecular biomarker for assessing the exposure to such pollutants. The establishment of prospective models for the formation of DNA adducts may help to understand the mechanisms of the effects. To identify the DNA adducts in this study, the fragmentation patterns of DNA-benzo(a)pyrene diol epoxide adducts were characterized by nanoflow liquid chromatography (LC) coupled to hybrid quadrupole orthogonal acceleration time-of-flight mass spectrometry (Q-TOF-MS). In the experiment, the DNA adducts were synthesized by reaction of calf thymus DNA with anti-benzo(a)pyrene-r-7,t-8-dihydrodiol-t-9,10-epoxide(+/-) (anti-BPDE). The major adducts of N2-deoxyguanosine-benzo(a)pyrene-7,8-dihydrodiol-9,10-epoxide (N2-dG-BPDE), N6-deoxyadenosine-benzo(a)pyrene-7,8-dihydrodiol-9,10-epoxide (N6-dA-BPDE), N4-deoxycytidine-benzo(a)pyrene-7,8-epoxide (N4-dC-BPDE), and N3-deoxythymidine-benzo(a)pyrene-7,8-dihydrodiol-9,10-epoxide adduct (N3-dT-BPDE) were identified by electrospray positive ionization with TOF-MS/MS scan mode. The results of this study demonstrated that the approach that utilizes collision-induced dissociation leading to a characteristic fragmentation pattern offers a distinct advantage for identification and elucidation of molecular structural features of the DNA adducts. The fragmentation patterns established in this study may be applied to identify DNA adducts in biological systems.

  16. Repair of furocoumarin adducts in mammalian cells

    SciTech Connect

    Zolan, M.E.; Smith, C.A.; Hanawalt, P.C.

    1984-12-01

    DNA repair was studied in cultured mammalian cells treated with the furocoumarins 8-methoxypsoralen (8-MOP), aminomethyl trioxsalen, or angelicin and irradiated with near UV light. The amount of DNA cross-linked by 8-MOP in normal human cells decreased by about one-half in 24 hours after treatment; no decrease was observed in xeroderma pigmentosum cells, group A. At present, it is not known to what extent this decrease represents complete repair events at the sites of cross-links. Furocoumarin adducts elicited excision repair in normal human and monkey cells but not in xeroderma pigmentosum group A cells. This excision repair resembled in several aspects that elicited by pyrimidine dimers, formed in DNA by irradiation with 254-nm UV light; however, it appeared that for at least 8-MOP and aminomethyl trioxsalen, removal of adducts was not as efficient as was the removal of pyrimidine dimers. A comparison was also made of repair in the 172-base-pair repetitive alpha-DNA component of monkey cells to repair in the bulk of the genome. Although repair elicited by pyrimidine dimers in alpha-DNA was the same as in the bulk DNA, that following treatment of cells with either aminomethyl trioxsalen or angelicin and near UV was markedly deficient in alpha-DNA. This deficiency reflected the removal of fewer adducts from alpha-DNA after the same initial adduct frequencies. These results could mean that each furocoumarin may produce several structurally distinct adducts to DNA in cells and that the capacity of cellular repair systems to remove these various adducts may vary greatly.

  17. General and rapid pyrimidine condensation by addressing the rate limiting aromatization.

    PubMed

    Fandrick, Daniel R; Reinhardt, Delia; Desrosiers, Jean-Nicolas; Sanyal, Sanjit; Fandrick, Keith R; Ma, Shengli; Grinberg, Nelu; Lee, Heewon; Song, Jinhua J; Senanayake, Chris H

    2014-06-06

    The rate limiting aromatization within the condensation approach toward pyrimidines utilizing amidines and activated olefins was addressed to provide for a general and rapid process. A strong solvent effect was elucidated to affect the rate for the initial alkoxide elimination from the intermediate Michael adduct wherein polar aprotic solvents demonstrate an addition controlled aromatization. Spectroscopic studies support a solvent dependent equilibrium between the amidine and alkoxide base wherein the rate for aromatization is optimal when the equilibrium toward the amidine anion was strongly favored.

  18. Complex Relationships between Occupation, Environment, DNA Adducts, Genetic Polymorphisms and Bladder Cancer in a Case-Control Study Using a Structural Equation Modeling

    PubMed Central

    Porru, Stefano; Pavanello, Sofia; Carta, Angela; Arici, Cecilia; Simeone, Claudio; Izzotti, Alberto; Mastrangelo, Giuseppe

    2014-01-01

    DNA adducts are considered an integrate measure of carcinogen exposure and the initial step of carcinogenesis. Their levels in more accessible peripheral blood lymphocytes (PBLs) mirror that in the bladder tissue. In this study we explore whether the formation of PBL DNA adducts may be associated with bladder cancer (BC) risk, and how this relationship is modulated by genetic polymorphisms, environmental and occupational risk factors for BC. These complex interrelationships, including direct and indirect effects of each variable, were appraised using the structural equation modeling (SEM) analysis. Within the framework of a hospital-based case/control study, study population included 199 BC cases and 213 non-cancer controls, all Caucasian males. Data were collected on lifetime smoking, coffee drinking, dietary habits and lifetime occupation, with particular reference to exposure to aromatic amines (AAs) and polycyclic aromatic hydrocarbons (PAHs). No indirect paths were found, disproving hypothesis on association between PBL DNA adducts and BC risk. DNA adducts were instead positively associated with occupational cumulative exposure to AAs (p = 0.028), whereas XRCC1 Arg 399 (p<0.006) was related with a decreased adduct levels, but with no impact on BC risk. Previous findings on increased BC risk by packyears (p<0.001), coffee (p<0.001), cumulative AAs exposure (p = 0.041) and MnSOD (p = 0.009) and a decreased risk by MPO (p<0.008) were also confirmed by SEM analysis. Our results for the first time make evident an association between occupational cumulative exposure to AAs with DNA adducts and BC risk, strengthening the central role of AAs in bladder carcinogenesis. However the lack of an association between PBL DNA adducts and BC risk advises that these snapshot measurements are not representative of relevant exposures. This would envisage new scenarios for biomarker discovery and new challenges such as repeated measurements at different critical life

  19. Complex relationships between occupation, environment, DNA adducts, genetic polymorphisms and bladder cancer in a case-control study using a structural equation modeling.

    PubMed

    Porru, Stefano; Pavanello, Sofia; Carta, Angela; Arici, Cecilia; Simeone, Claudio; Izzotti, Alberto; Mastrangelo, Giuseppe

    2014-01-01

    DNA adducts are considered an integrate measure of carcinogen exposure and the initial step of carcinogenesis. Their levels in more accessible peripheral blood lymphocytes (PBLs) mirror that in the bladder tissue. In this study we explore whether the formation of PBL DNA adducts may be associated with bladder cancer (BC) risk, and how this relationship is modulated by genetic polymorphisms, environmental and occupational risk factors for BC. These complex interrelationships, including direct and indirect effects of each variable, were appraised using the structural equation modeling (SEM) analysis. Within the framework of a hospital-based case/control study, study population included 199 BC cases and 213 non-cancer controls, all Caucasian males. Data were collected on lifetime smoking, coffee drinking, dietary habits and lifetime occupation, with particular reference to exposure to aromatic amines (AAs) and polycyclic aromatic hydrocarbons (PAHs). No indirect paths were found, disproving hypothesis on association between PBL DNA adducts and BC risk. DNA adducts were instead positively associated with occupational cumulative exposure to AAs (p = 0.028), whereas XRCC1 Arg 399 (p<0.006) was related with a decreased adduct levels, but with no impact on BC risk. Previous findings on increased BC risk by packyears (p<0.001), coffee (p<0.001), cumulative AAs exposure (p = 0.041) and MnSOD (p = 0.009) and a decreased risk by MPO (p<0.008) were also confirmed by SEM analysis. Our results for the first time make evident an association between occupational cumulative exposure to AAs with DNA adducts and BC risk, strengthening the central role of AAs in bladder carcinogenesis. However the lack of an association between PBL DNA adducts and BC risk advises that these snapshot measurements are not representative of relevant exposures. This would envisage new scenarios for biomarker discovery and new challenges such as repeated measurements at different critical life

  20. Relationships between DNA adduct formation and carcinogenesis

    SciTech Connect

    Swenberg, J.A.; Richardson, F.C.; Boucheron, J.A.; Dyroff, M.C.

    1985-10-01

    An impressive array of evidence has been obtained during the past decade establishing correlations between specific DNA adducts and carcinogenesis. Many of the studies utilized organ specific differences in carcinogenesis to establish the correlations. More recently, we have investigated similar relationships between target and nontarget cell populations within the liver. Chronic exposure to methylating hepatocarcinogens predominantly induces hemangiosarcomas, whereas exposure to ethylating agents causes hepatocellular carcinomas. This cell specificity in carcinogenesis correlates well with the presence of promutagenic DNA adducts. In the case of methylating agents, the nonparenchymal cells accumulate O6-methylguanine whereas the hepatocytes do not. Exposure to ethylating agents leads to accumulation of O4-ethyldeoxythymidine, but not O6-ethyldeoxyguanosine in hepatocytes. These differences reflect the ability of the two cell populations to repair O6-alkylguanine and the extent of purine and pyrimidine alkylation with methylating and ethylating agents. Hepatocytes of rats exposed to diethylnitrosamine for 28 days have four to five times more promutagenic DNA adducts (O6-alkyldeoxyguanosine and O4-alkyldeoxythymidine) than hepatocytes of rats exposed to nearly equimolar doses of dimethylhydrazine. Both O6-methylguanine and O4-methyldeoxythymidine are rapidly repaired by rat hepatocytes, while only O6-ethyldeoxyguanosine is rapidly repaired. Studies comparing the relationship between the induction of gamma-glutamyl transpeptidase-positive foci, hepatocellular carcinoma and promutagenic lesions such as O4-ethyldeoxythymidine will be useful in understanding associations between the molecular dosimetry of DNA adducts, initiation, and progression of hepatocarcinogenesis.

  1. Cigarette side-stream smoke lung and bladder carcinogenesis: inducing mutagenic acrolein-DNA adducts, inhibiting DNA repair and enhancing anchorage-independent-growth cell transformation.

    PubMed

    Lee, Hyun-Wook; Wang, Hsiang-Tsui; Weng, Mao-wen; Chin, Chiu; Huang, William; Lepor, Herbert; Wu, Xue-Ru; Rom, William N; Chen, Lung-Chi; Tang, Moon-shong

    2015-10-20

    Second-hand smoke (SHS) is associated with 20-30% of cigarette-smoke related diseases, including cancer. Majority of SHS (>80%) originates from side-stream smoke (SSS). Compared to mainstream smoke, SSS contains more tumorigenic polycyclic aromatic hydrocarbons and acrolein (Acr). We assessed SSS-induced benzo(a)pyrene diol epoxide (BPDE)- and cyclic propano-deoxyguanosine (PdG) adducts in bronchoalveolar lavage (BAL), lung, heart, liver, and bladder-mucosa from mice exposed to SSS for 16 weeks. In SSS exposed mice, Acr-dG adducts were the major type of PdG adducts formed in BAL (p < 0.001), lung (p < 0.05), and bladder mucosa (p < 0.001), with no significant accumulation of Acr-dG adducts in heart or liver. SSS exposure did not enhance BPDE-DNA adduct formation in any of these tissues. SSS exposure reduced nucleotide excision repair (p < 0.01) and base excision repair (p < 0.001) in lung tissue. The levels of DNA repair proteins, XPC and hOGG1, in lung tissues of exposed mice were significantly (p < 0.001 and p < 0.05) lower than the levels in lung tissues of control mice. We found that Acr can transform human bronchial epithelial and urothelial cells in vitro. We propose that induction of mutagenic Acr-DNA adducts, inhibition of DNA repair, and induction of cell transformation are three mechanisms by which SHS induces lung and bladder cancers.

  2. Eleven supramolecular adducts of 5,7-dimethyl-1,8-naphthyridine-2-amine and organic acids assembled by classical hydrogen bonds and other noncovalent intermolecular interactions

    NASA Astrophysics Data System (ADS)

    Dong, Lingfeng; Jin, Shouwen; Wang, Yining; Xie, Xinxin; Liu, Bin; Wang, Daqi

    2017-10-01

    This article demonstrates 5,7-dimethyl-1,8-naphthyridine-2-amine based supramolecular adducts formation in eleven crystalline solids 1-11, in which the acidic moiety have been integrated. Addition of equivalents of the acid to the solution of 5,7-dimethyl-1,8-naphthyridine-2-amine generates the corresponding supramolecular assemblies. Except 8, all the compounds crystallize as their organic salts with the acidic proton at the organic acids transferred to the aromatic nitrogen of the 5,7-dimethyl-1,8-naphthyridine-2-amine moiety. All adducts have been characterized through IR, mp, elemental analysis and X-ray single crystal diffraction technique. The major driving force in the adducts 1-11 is attributed to the classical hydrogen-bonds arising from 5,7-dimethyl-1,8-naphthyridine-2-amine and the acids. The other extensive non-covalent interactions also play great functions in space association of the molecular counterparts in relevant crystals. The homo or hetero supramolecular synthons or both were found at these adducts. The common R22(8) graph set has been observed in all of the adducts due to the H-bonds and the non-covalent associations. For the synergistic interactions of the classical H-bonds and the various non-covalent associations, these adducts displayed 2D/3D structures.

  3. Cigarette side-stream smoke lung and bladder carcinogenesis: inducing mutagenic acrolein-DNA adducts, inhibiting DNA repair and enhancing anchorage-independent-growth cell transformation

    PubMed Central

    Chin, Chiu; Huang, William; Lepor, Herbert; Wu, Xue-Ru; Rom, William N.; Chen, Lung-Chi; Tang, Moon-shong

    2015-01-01

    Second-hand smoke (SHS) is associated with 20–30% of cigarette-smoke related diseases, including cancer. Majority of SHS (>80%) originates from side-stream smoke (SSS). Compared to mainstream smoke, SSS contains more tumorigenic polycyclic aromatic hydrocarbons and acrolein (Acr). We assessed SSS-induced benzo(a)pyrene diol epoxide (BPDE)- and cyclic propano-deoxyguanosine (PdG) adducts in bronchoalveolar lavage (BAL), lung, heart, liver, and bladder-mucosa from mice exposed to SSS for 16 weeks. In SSS exposed mice, Acr-dG adducts were the major type of PdG adducts formed in BAL (p < 0.001), lung (p < 0.05), and bladder mucosa (p < 0.001), with no significant accumulation of Acr-dG adducts in heart or liver. SSS exposure did not enhance BPDE-DNA adduct formation in any of these tissues. SSS exposure reduced nucleotide excision repair (p < 0.01) and base excision repair (p < 0.001) in lung tissue. The levels of DNA repair proteins, XPC and hOGG1, in lung tissues of exposed mice were significantly (p < 0.001 and p < 0.05) lower than the levels in lung tissues of control mice. We found that Acr can transform human bronchial epithelial and urothelial cells in vitro. We propose that induction of mutagenic Acr-DNA adducts, inhibition of DNA repair, and induction of cell transformation are three mechanisms by which SHS induces lung and bladder cancers. PMID:26431382

  4. A new approach to evaluating the extent of Michael adduct formation to PAH quinones: tetramethylammonium hydroxide (TMAH) thermochemolysis with GC/MS.

    PubMed

    Briggs, Mary K; Desavis, Emmanuel; Mazzer, Paula A; Sunoj, R B; Hatcher, Susan A; Hadad, Christopher M; Hatcher, Patrick G

    2003-11-01

    Polycyclic aromatic hydrocarbons (PAHs) are environmental pollutants that are converted to cytotoxic and carcinogenic metabolites, quinones, by detoxifying enzyme systems in animals. PAH metabolites such as the quinones can form Michael adducts with biological macromolecules containing reactive nucleophiles, making detection of exposure to PAHs difficult using conventional techniques. A technique has been developed for detecting exposure to PAHs. Tetramethylammonium hydroxide (TMAH) thermochemolysis coupled with GC/MS is proposed as an assay method for PAH quinones that have formed Michael adducts with biological molecules. Three PAH quinones (1,4-naphthoquinone, 1,2-naphthoquinone, and 1,4-anthraquinone) and 1,4-benzoquinone were reacted with cysteine, and the TMAH thermochemolysis method was used to assay for both thiol and amine adduction between the quinones and the cysteine. Additional studies with 1,4-naphthoquinone adducts to glutathione and bovine serum albumin showed the same thiol and amine TMAH thermochemolysis products with larger peptides as was observed with cysteine adducts. The TMAH GC/MS method clearly shows great promise for detecting PAH quinones, produced by enzymatic conversion of PAHs in biological systems, that have been converted to respective Michael adducts.

  5. Supramolecular Adducts of Cucurbit[7]uril and Amino Acids in the Gas Phase

    NASA Astrophysics Data System (ADS)

    Kovalenko, Ekaterina; Vilaseca, Marta; Díaz-Lobo, Mireia; Masliy, A. N.; Vicent, Cristian; Fedin, Vladimir P.

    2016-02-01

    The complexation of the macrocyclic cavitand cucurbit[7]uril (Q7) with a series of amino acids (AA) with different side chains (Asp, Asn, Gln, Ser, Ala, Val, and Ile) is investigated by ESI-MS techniques. The 1:1 [Q7 + AA + 2H]2+ adducts are observed as the base peak when equimolar Q7:AA solutions are electrosprayed, whereas the 1:2 [Q7 + 2AA + 2H]2+ dications are dominant when an excess of the amino acid is used. A combination of ion mobility mass spectrometry (IM-MS) and DFT calculations of the 1:1 [Q7 + AA + 2H]2+ (AA = Tyr, Val, and Ser) adducts is also reported and proven to be unsuccessful at discriminating between exclusion or inclusion-type conformations in the gas phase. Collision induced dissociation (CID) revealed that the preferred dissociation pathways of the 1:1 [Q7 + AA + 2H]2+ dications are strongly influenced by the identity of the amino acid side chain, whereas ion molecule reactions towards N-butylmethylamine displayed a common reactivity pattern comprising AA displacement. Special emphasis is given on the differences between the gas-phase behavior of the supramolecular adducts with amino acids (AA = Asp, Asn, Gln, Ser, Ala, Val, and Ile) and those featuring basic (Lys and Arg) and aromatic (Tyr and Phe) side chains.

  6. Quantification of 3-nitrobenzanthrone-DNA adducts using online column-switching HPLC-electrospray tandem mass spectrometry.

    PubMed

    Gamboa da Costa, Gonçalo; Singh, Rajinder; Arlt, Volker M; Mirza, Amin; Richards, Meirion; Takamura-Enya, Takeji; Schmeiser, Heinz H; Farmer, Peter B; Phillips, David H

    2009-11-01

    The aromatic nitroketone 3-nitrobenzanthrone (3-nitro-7H-benz[de]anthracen-7-one; 3-NBA) is an extremely potent mutagen and a suspected human carcinogen detected in the exhaust of diesel engines and in airborne particulate matter. 3-NBA is metabolically activated via reduction of the nitro group to the hydroxylamine (N-OH-3-ABA) to form covalent DNA adducts. Thus far, the detection and quantification of covalent 3-NBA-DNA adducts has relied solely on (32)P-postlabeling methodologies. In order to expand the range of available techniques for the detection and improved quantification of 3-NBA-DNA adducts, we have developed a method based upon online column-switching HPLC coupled to electrospray tandem mass spectrometry, with isotopic dilution of (15)N-labeled internal standards. This methodology was applied to the determination of three 3-NBA-derived adducts: 2-(2'-deoxyguanosin-N(2)-yl)-3-aminobenzanthrone (dG-N(2)-3-ABA), N-(2'-deoxyguanosin-8-yl)-3-aminobenzanthrone (dG-C8-N-3-ABA) and 2-(2'-deoxyguanosine-8-yl)-3-aminobenzanthrone (dG-C8-C2-3-ABA). Dose-dependent increases were observed for all three adducts when salmon testis DNA was reacted with N-acetoxy-3-aminobenzanthrone (N-AcO-3-ABA). dG-C8-C2-3-ABA was detected at much lower levels (overall 1%) than the other two adducts. DNA samples isolated from tissues of rats treated either intratracheally with 3-NBA or intraperitoneally with N-OH-3-ABA were analyzed by mass spectrometry, and the results compared to those obtained by (32)P-postlabeling. The method required 50 microg of hydrolyzed animal DNA on column and the limit of detection was 2.0 fmol for each adduct. dG-C8-C2-3-ABA was not observed in any of the samples providing confirmation that it is not formed in vivo. Linear regression analysis of the levels of dG-N(2)-3-ABA and dG-C8-N-3-ABA in the rat DNA showed a reasonable correlation between the two methods (R(2) = 0.88 and 0.93, respectively). In summary, the mass spectrometric method is a faster, more

  7. Selectivity Control in the Tandem Aromatization of Bio‐Based Furanics Catalyzed by Solid Acids and Palladium

    PubMed Central

    Genuino, Homer C.; Thiyagarajan, Shanmugam; van der Waal, Jan C.; van Haveren, Jacco; Weckhuysen, Bert M.

    2016-01-01

    Abstract Bio‐based furanics can be aromatized efficiently by sequential Diels–Alder (DA) addition and hydrogenation steps followed by tandem catalytic aromatization. With a combination of zeolite H‐Y and Pd/C, the hydrogenated DA adduct of 2‐methylfuran and maleic anhydride can thus be aromatized in the liquid phase and, to a certain extent, decarboxylated to give high yields of the aromatic products 3‐methylphthalic anhydride and o‐ and m‐toluic acid. Here, it is shown that a variation in the acidity and textural properties of the solid acid as well as bifunctionality offers a handle on selectivity toward aromatic products. The zeolite component was found to dominate selectivity. Indeed, a linear correlation is found between 3‐methylphthalic anhydride yield and the product of (strong acid/total acidity) and mesopore volume of H‐Y, highlighting the need for balanced catalyst acidity and porosity. The efficient coupling of the dehydration and dehydrogenation steps by varying the zeolite‐to‐Pd/C ratio allowed the competitive decarboxylation reaction to be effectively suppressed, which led to an improved 3‐methylphthalic anhydride/total aromatics selectivity ratio of 80 % (89 % total aromatics yield). The incorporation of Pd nanoparticles in close proximity to the acid sites in bifunctional Pd/H‐Y catalysts also afforded a flexible means to control aromatic products selectivity, as further demonstrated in the aromatization of hydrogenated DA adducts from other diene/dienophile combinations. PMID:27557889

  8. Selectivity Control in the Tandem Aromatization of Bio-Based Furanics Catalyzed by Solid Acids and Palladium.

    PubMed

    Genuino, Homer C; Thiyagarajan, Shanmugam; van der Waal, Jan C; de Jong, Ed; van Haveren, Jacco; van Es, Daan S; Weckhuysen, Bert M; Bruijnincx, Pieter C A

    2017-01-10

    Bio-based furanics can be aromatized efficiently by sequential Diels-Alder (DA) addition and hydrogenation steps followed by tandem catalytic aromatization. With a combination of zeolite H-Y and Pd/C, the hydrogenated DA adduct of 2-methylfuran and maleic anhydride can thus be aromatized in the liquid phase and, to a certain extent, decarboxylated to give high yields of the aromatic products 3-methylphthalic anhydride and o- and m-toluic acid. Here, it is shown that a variation in the acidity and textural properties of the solid acid as well as bifunctionality offers a handle on selectivity toward aromatic products. The zeolite component was found to dominate selectivity. Indeed, a linear correlation is found between 3-methylphthalic anhydride yield and the product of (strong acid/total acidity) and mesopore volume of H-Y, highlighting the need for balanced catalyst acidity and porosity. The efficient coupling of the dehydration and dehydrogenation steps by varying the zeolite-to-Pd/C ratio allowed the competitive decarboxylation reaction to be effectively suppressed, which led to an improved 3-methylphthalic anhydride/total aromatics selectivity ratio of 80 % (89 % total aromatics yield). The incorporation of Pd nanoparticles in close proximity to the acid sites in bifunctional Pd/H-Y catalysts also afforded a flexible means to control aromatic products selectivity, as further demonstrated in the aromatization of hydrogenated DA adducts from other diene/dienophile combinations.

  9. NITRO MUSK ADDUCTS OF RAINBOW TROUT ...

    EPA Pesticide Factsheets

    Rainbow trout and other fish species can serve as 'sentinel' species for the assessment of ecological status and the presence of certain environmental contaminants. As such they act as bioindicators of exposure. Here we present seminal data regarding dose-response and toxicokinetics of trout hemoglobin adduct formation from exposure to nitro musks that are frequently used as fragrance ingredients in formulations of personal care products. Hemoglobin adducts serve as biomarkers of exposure of the sentinel species as we have shown in previous studies of hemoglobin adducts formed in trout and environmental carp exposed to musk xylene (MX) and musk ketone (MK). Gas chromatography-electron capture negative ion chemical ionization-mass spectrometry (GC-NICI-MS) employing selected ion monitoring is used to measure 4-amino-MX (4-AMX), 2-amino-MX (2-AMX), and 2-amino-MK (2-AMK) released by alkaline hydrolysis from the sulfinamide adducts of hemoglobin. Dose-response and toxicokinetics were investigated using this sensitive method for analysis of these metabolites. In the dose-response investigation, the concentrations of 4-AMX and 2-2AMX are observed to pass through a maximum at 0.10 mg/g. In the case of 2-AMK, the adduct concentration is almost the same at dosages in the range of 0.030 to 0.10 mg/g. For toxicokinetics, the concentration of the metabolites in the Hb reaches a maximum in the 3-day sample after administration of MX or MK. Further elimination of the metabo

  10. DNA adducts, benzo(a)pyrene monooxygenase activity, and lysosomal membrane stability in Mytilus galloprovincialis from different areas in Taranto coastal waters (Italy).

    PubMed

    Pisoni, M; Cogotzi, L; Frigeri, A; Corsi, I; Bonacci, S; Iacocca, A; Lancini, L; Mastrototaro, F; Focardi, S; Svelto, M

    2004-10-01

    The aim of this study was to investigate the impact of environmental pollution at different stations along the Taranto coastline (Ionian Sea, Puglia, Italy) using several biomarkers of exposure and the effect on mussels, Mytilus galloprovincialis, collected in October 2001 and October 2002. Five sampling sites were compared with a "cleaner" reference site in the Aeronautics Area. In this study we also investigated the differences between adduct levels in gills and digestive gland. This Taranto area is the most significant industrial settlement on the Ionian Sea known to be contaminated by polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls, heavy metals, etc. Exposure to PAHs was evaluated by measuring DNA adduct levels and benzo(a)pyrene monooxygenase activity (B(a)PMO); DNA adducts were analyzed by 32P-postlabeling with nuclease P1 enhancement in both gills and digestive glands to evaluate differences between DNA adduct levels in the two tissues. B(a)PMO was assayed in the microsomal fraction of the digestive glands as a result of the high expression of P450-metabolizing enzymes in this tissue. Lysosomal membrane stability, a potential biomarker of anthropogenic stress, was also evaluated in the digestive glands of mussels, by measuring the latent activity of beta-N-acetylhexosaminidase. Induction of DNA adducts was evident in both tissues, although the results revealed large tissue differences in DNA adduct formation. In fact, gills showed higher DNA adduct levels than did digestive gland. No significant differences were found in DNA adduct levels over time, with both tissues providing similar results in both years. DNA adduct levels were correlated with B(a)PMO activity in digestive gland in both years (r = 0.60 in 2001; r = 0.73 in 2002). Increases were observed in B(a)PMO activity and DNA adduct levels at different stations; no statistical difference was observed in B(a)PMO activity over the two monitoring campaigns. The membrane labilization

  11. Genetic polymorphisms in catalase and CYP1B1 determine DNA adduct formation by benzo(a)pyrene ex vivo.

    PubMed

    Schults, Marten A; Chiu, Roland K; Nagle, Peter W; Wilms, Lonneke C; Kleinjans, Jos C; van Schooten, Frederik J; Godschalk, Roger W

    2013-03-01

    Genetic polymorphisms can partially explain the large inter-individual variation in DNA adduct levels following exposure to polycyclic aromatic hydrocarbons. Effects of genetic polymorphisms on DNA adduct formation are difficult to assess in human studies because exposure misclassification attenuates underlying relationships. Conversely, ex vivo studies offer the advantage of controlled exposure settings, allowing the possibility to better elucidate genotype-phenotype relationships and gene-gene interactions. Therefore, we exposed lymphocytes of 168 non-smoking volunteers ex vivo to the environmental pollutant benzo(a)pyrene (BaP) and BaP-related DNA adducts were quantified. Thirty-four genetic polymorphisms were assessed in genes involved in carcinogen metabolism, oxidative stress and DNA repair. Polymorphisms in catalase (CAT, rs1001179) and cytochrome P450 1B1 (CYP1B1, rs1800440) were significantly associated with DNA adduct levels, especially when combined. Moreover, reverse transcription-polymerase chain reaction (RT-PCR) analysis in a subset of 30 subjects revealed that expression of catalase correlated strongly with expression of CYP1B1 (R = 0.92, P < 0.001). To further investigate the mechanism by which catalase influences CYP1B1 and how they simultaneously affect BaP-related DNA adduct levels, catalase expression was transiently knocked down in the human lung epithelial cell line A549. Although catalase knockdown did not immediately change CYP1B1 gene expression, recovery of catalase expression 8 h after the knockdown coincided with a 2.2-fold increased expression of CYP1B1 (P < 0.05). We conclude that the genetic polymorphism in the promoter region of CAT may determine the amount and activity of catalase, which may subsequently regulate the expression of CYP1B1. As a result, both genetic polymorphisms modulate DNA adduct levels in lymphocytes by BaP ex vivo.

  12. Association between plasma BPDE‐Alb adduct concentrations and DNA damage of peripheral blood lymphocytes among coke oven workers

    PubMed Central

    Wang, Hong; Chen, Weihong; Zheng, Hongyan; Guo, Liang; Liang, Huashan; Yang, Xiaobo; Bai, Yun; Sun, Jianya; Su, Yougong; Chen, Yongwen; Yuan, Jing; Bi, Yongyi; Wei, Qingyi; Wu, Tangchun

    2007-01-01

    Objectives Coke oven emissions (COE) containing polycyclic aromatic hydrocarbons (PAHs) can induce both benzo[a]pyrene‐r‐7, t‐8, t‐9,c‐10‐tetrahydotetrol‐albumin (BPDE‐Alb) adducts and DNA damage. However, the relation between these biomarkers for early biological effects is not well documented in coke oven workers. Methods In this study, the authors recruited 207 male workers exposed to COE and 102 controls not exposed to COE in the same steel plant in northern China. They measured BPDE‐Alb adduct concentrations in plasma with reverse‐phase high performance liquid chromatography and DNA damage in peripheral blood lymphocytes with alkaline comet assay. Results The results showed that the median concentration of BPDE‐Alb adducts in the exposed group (34.36 fmol/mg albumin) was significantly higher than that in the control group (21.90 fmol/mg albumin, p = 0.012). The mean Olive tail moment (Olive TM) of DNA damage in the exposed and control groups were 1.20 and 0.63, respectively (p = 0.000). Multivariate logistic regression analysis revealed that the odds ratio (OR) for BPDE‐Alb adduct and Olive TM associated with the exposure were 1.72 (95% CI 1.06 to 2.81) and 1.96 (95% CI 1.20 to 3.19), respectively. These results show significant correlations between the concentrations of BPDE‐Alb adduct and Olive TM levels in exposed group (r = 0.235, p = 0.001) but not in control group (r = 0.093, p = 0.353). Conclusion The results suggest that occupational exposure to COE may induce both BPDE–Alb adducts and DNA damage in the lymphocytes of coke oven workers and that these two markers are useful for monitoring exposure to COE in the workplace. PMID:17449561

  13. Association between plasma BPDE-Alb adduct concentrations and DNA damage of peripheral blood lymphocytes among coke oven workers.

    PubMed

    Wang, Hong; Chen, Weihong; Zheng, Hongyan; Guo, Liang; Liang, Huashan; Yang, Xiaobo; Bai, Yun; Sun, Jianya; Su, Yougong; Chen, Yongwen; Yuan, Jing; Bi, Yongyi; Wei, Qingyi; Wu, Tangchun

    2007-11-01

    Coke oven emissions (COE) containing polycyclic aromatic hydrocarbons (PAHs) can induce both benzo[a]pyrene-r-7, t-8, t-9,c-10-tetrahydotetrol-albumin (BPDE-Alb) adducts and DNA damage. However, the relation between these biomarkers for early biological effects is not well documented in coke oven workers. In this study, the authors recruited 207 male workers exposed to COE and 102 controls not exposed to COE in the same steel plant in northern China. They measured BPDE-Alb adduct concentrations in plasma with reverse-phase high performance liquid chromatography and DNA damage in peripheral blood lymphocytes with alkaline comet assay. The results showed that the median concentration of BPDE-Alb adducts in the exposed group (34.36 fmol/mg albumin) was significantly higher than that in the control group (21.90 fmol/mg albumin, p = 0.012). The mean Olive tail moment (Olive TM) of DNA damage in the exposed and control groups were 1.20 and 0.63, respectively (p = 0.000). Multivariate logistic regression analysis revealed that the odds ratio (OR) for BPDE-Alb adduct and Olive TM associated with the exposure were 1.72 (95% CI 1.06 to 2.81) and 1.96 (95% CI 1.20 to 3.19), respectively. These results show significant correlations between the concentrations of BPDE-Alb adduct and Olive TM levels in exposed group (r = 0.235, p = 0.001) but not in control group (r = 0.093, p = 0.353). The results suggest that occupational exposure to COE may induce both BPDE-Alb adducts and DNA damage in the lymphocytes of coke oven workers and that these two markers are useful for monitoring exposure to COE in the workplace.

  14. The carcinogen 1-methylpyrene forms benzylic DNA adducts in mouse and rat tissues in vivo via a reactive sulphuric acid ester.

    PubMed

    Bendadani, Carolin; Meinl, Walter; Monien, Bernhard H; Dobbernack, Gisela; Glatt, Hansruedi

    2014-03-01

    The common polycyclic aromatic hydrocarbon 1-methylpyrene is hepatocarcinogenic in the newborn mouse assay. In vitro studies showed that it is metabolically activated via benzylic hydroxylation and sulphation to a reactive ester, which forms benzylic DNA adducts, N(2)-(1-methylpyrenyl)-2'-deoxyguanosine (MPdG) and N(6)-(1-methylpyrenyl)-2'-deoxyadenosine (MPdA). Formation of these adducts was also observed in animals treated with the metabolites, 1-hydroxymethylpyrene and 1-sulphooxymethylpyrene (1-SMP), whereas corresponding data are missing for 1-methylpyrene. In the present study, we treated mice with 1-methylpyrene and subsequently analysed blood serum for the presence of the reactive metabolite 1-SMP and tissue DNA for the presence of MPdG and MPdA adducts. We used wild-type mice and a mouse line transgenic for human sulphotransferases (SULT) 1A1 and 1A2, males and females. All analyses were conducted using ultra-performance liquid chromatography coupled with tandem mass spectrometry, for the adducts with isotope-labelled internal standards. 1-SMP was detected in all treated animals. Its serum level was higher in transgenic mice than in the wild-type (p < 0.001). Likewise, both adducts were detected in liver, kidney and lung DNA of all exposed animals. The transgene significantly enhanced the level of each adduct in each tissue of both sexes (p < 0.01-0.001). Adduct levels were highest in the liver, the target tissue of carcinogenesis, in each animal model used. MPdG and MPdA adducts were also observed in rats treated with 1-methylpyrene. Our findings corroborate the hypothesis that 1-SMP is indeed the ultimate carcinogen of 1-methylpyrene and that human SULT are able to mediate the terminal activation in vivo.

  15. Free flow electrophoresis separation and AMS quantitation of 14C-naphthalene-protein adducts

    NASA Astrophysics Data System (ADS)

    Buchholz, Bruce A.; Haack, Kurt W.; Sporty, Jennifer L.; Buckpitt, Alan R.; Morin, Dexter

    2010-04-01

    Naphthalene is a volatile aromatic hydrocarbon to which humans are exposed from a variety of sources including mobile air sources and cigarette smoke. Naphthalene produces dose-(concentration)dependent injury to airway epithelial cells of murine lung which is observed at concentrations well below the current occupational exposure standard. Toxicity is dependent upon the cytochrome P450 mediated metabolic activation of the parent substrate to unstable metabolites which become bound covalently to tissue proteins. Nearly 70 proteins have been identified as forming adducts with reactive naphthalene metabolites using in vitro systems but very little work has been conducted in vivo because reasonably large amounts (100 μCi) of 14C labeled parent compound must be administered to generate detectable adduct levels on storage phosphor screens following separation of labeled proteins by 2D gel electrophoresis. The work described here was done to provide proof of concept that protein separation by free flow electrophoresis followed by AMS detection of protein fractions containing protein bound reactive metabolites would provide adducted protein profiles in animals dosed with trace quantities of labeled naphthalene. Mice were administered 200 mg/kg naphthalene intraperitoneally at a calculated specific activity of 2 DPM/nmol (1 pCi/nmol) and respiratory epithelial tissue was obtained by lysis lavage 4 h post injection. Free flow electrophoresis (FFE) separates proteins in the liquid phase over a large pH range (2.5-11.5) using low molecular weight acids and bases to modify the pH. The apparatus separates fractions into standard 96-well plates that can be used in other protein analysis techniques. The buffers of the fractions have very high carbon content, however, and need to be dialyzed to yield buffers compatible with 14C-AMS. We describe the processing techniques required to couple FFE to AMS for quantitation of protein adducts.

  16. Free flow electrophoresis separation and AMS quantitation of C-naphthalene-protein adducts.

    PubMed

    Buchholz, Bruce A; Haack, Kurt W; Sporty, Jennifer L; Buckpitt, Alan R; Morin, Dexter

    2010-04-01

    Naphthalene is a volatile aromatic hydrocarbon to which humans are exposed from a variety of sources including mobile air sources and cigarette smoke. Naphthalene produces dose- (concentration) dependent injury to airway epithelial cells of murine lung which is observed at concentrations well below the current occupational exposure standard. Toxicity is dependent upon the cytochrome P450 mediated metabolic activation of the parent substrate to unstable metabolites which become bound covalently to tissue proteins. Nearly 70 proteins have been identified as forming adducts with reactive naphthalene metabolites using in vitro systems but very little work has been conducted in vivo because reasonably large amounts (100 μCi) of (14)C labeled parent compound must be administered to generate detectable adduct levels on storage phosphor screens following separation of labeled proteins by 2 D gel electrophoresis. The work described here was done to provide proof of concept that protein separation by free flow electrophoresis followed by AMS detection of protein fractions containing protein bound reactive metabolites would provide adducted protein profiles in animals dosed with trace quantities of labeled naphthalene. Mice were administered 200 mg/kg naphthalene intraperitoneally at a calculated specific activity of 2 DPM/nmol (1 pCi/nmol) and respiratory epithelial tissue was obtained by lysis lavage 4 hr post injection. Free flow electrophoresis (FFE) separates proteins in the liquid phase over a large pH range (2.5-11.5) using low molecular weight acids and bases to modify the pH. The apparatus separates fractions into standard 96-well plates that can be used in other protein analysis techniques. The buffers of the fractions have very high carbon content, however, and need to be dialyzed to yield buffers compatible with (14)C-AMS. We describe the processing techniques required to couple FFE to AMS for quantitation of protein adducts.

  17. Modulation of the Effect of Prenatal PAH Exposure on PAH-DNA Adducts in Cord Blood by Plasma Antioxidants

    PubMed Central

    Kelvin, Elizabeth A.; Edwards, Susan; Jedrychowski, Wieslaw; Schleicher, Rosemary L.; Camann, David; Tang, Deliang; Perera, Frederica P.

    2011-01-01

    The fetus is more susceptible than the adult to the effects of certain carcinogens, such as polycyclic aromatic hydrocarbons (PAH). Nutritional factors, including antioxidants, have been shown to have a protective effect on carcinogen-DNA adducts and cancer risk in adults. We investigated whether the effect of prenatal airborne PAH exposure, measured by personal air monitoring during pregnancy, on the level of PAH-DNA adducts in a baby's cord blood is modified by the concentration of micronutrients in maternal and cord blood. The micronutrients examined were: retinol (vitamin A), α-tocopherol and γ-tocopherol (vitamin E), and carotenoids. With the use of multiple linear regression, we found a significant interaction between prenatal PAH exposure and cord blood concentration of α-tocopherol and carotenoids in predicting the concentration of PAH adducts in cord blood. The association between PAH exposure and PAH adducts was much stronger among those with low α-tocopherol (β = 0.15; P = 0.001) and among those with low carotenoids (β = 0.16; P < 0.001) compared with babies with high levels of these micronutrients (among those with high α-tocopherol: β = 0.05; P = 0.165; among those with high carotenoids: β = 0.06; P = 0.111). These results suggest a protective effect of micronutrients on the DNA damage and potential cancer risk associated with prenatal PAH exposure. PMID:19661084

  18. Cytochrome c Adducts with PCB Quinoid Metabolites

    PubMed Central

    Li, Miao; Teesch, Lynn M.; Murry, Daryl J.; Pope, R. Marshal; Li, Yalan; Robertson, Larry W.; Ludewig, Gabriele

    2015-01-01

    PCBs are a group of 209 individual congeners widely used as industrial chemicals. PCBs are found as by-products in dye and paint manufacture and are legacy, ubiquitous and persistent as human and environmental contaminants. PCBs with fewer chlorine atoms may be metabolized to hydroxy- and dihydroxy- metabolites and further oxidized to quinoid metabolites both in vitro and in vivo. Specifically, quinoid metabolites may form adducts on nucleophilic sites within cells. We hypothesized that the PCB-quinones covalently bind to cytochrome c and thereby cause defects in the function of cytochrome c. In this study synthetic PCB quinones (2-(4’-chlorophenyl)-1,4-benzoquinone, 2-(3’, 5’-dichlorophenyl)-1,4-benzoquinone, 2-(3’,4’, 5’-trichlorophenyl)-1,4-benzoquinone, and 2-(4’-chlorophenyl)-3,6-dichloro-1,4-benzoquinone) were incubated with cytochrome c, and adducts were detected by LC-MS and MALDI TOF. SDS PAGE gel electrophoresis was employed to separate the adducted proteins, while trypsin digestion and LC-MS/MS were applied to identify the amino acid binding sites on cytochrome c. Conformation change of cytochrome c after binding with PCB3-para-quinone was investigated by SYBYL-X simulation and cytochrome c function was examined. We found that more than one molecule of PCB-quinone may bind to one molecule of cytochrome c. Lysine and glutamic acid were identified as the predominant binding sites. Software simulation showed conformation changes of adducted cytochrome c. Additionally, cross-linking of cytochrome c was observed on the SDS PAGE gel. Cytochrome c was found to be in the reduced form after incubation with PCB quinones. These data provide evidence that the covalent binding of PCB quinone metabolites to cytochrome c may be included among the toxic effects of PCBs. PMID:26062463

  19. Immunochemical properties of malondialdehyde-protein adducts.

    PubMed

    Lung, C C; Fleisher, J H; Meinke, G; Pinnas, J L

    1990-03-27

    Malondialdehyde (MDA), a product of lipid peroxidation, can bind to and modify proteins by adduct formation. To determine whether MDA adducts were immunogenic, MDA was added to rabbit serum albumin (RSA) in order to characterize MDA-proteins and to immunize rabbits. Bound MDA was proportional to the concentration of MDA added in the range of 2.5-20 mM as measured by thiobarbituric acid reactivity. MDA adducts of RSA migrated further toward the anode than native serum protein in zone and immunoelectrophoresis indicating increased negative charge. Rabbits immunized with MDA-RSA produced high titers of IgG antibodies to MDA-RSA as measured by enzyme-linked immunosorbent assay (ELISA). Hapten specificity of the antibody was demonstrated by antisera reactivity with MDA-RSA but not with unaltered RSA. Our findings support the possibility that MDA may serve as a hapten to form neoantigens which may represent a pathway by which lipid peroxidation could produce tissue damage via an immunologic mechanism.

  20. Supramolecular photochemistry and photophysics. Mutual inhibition of host and guest photochemistry and luminescence in the adduct of an anthraceno-crown ether with Pt(bpy)(NH sub 3 ) sub 2 sup 2+

    SciTech Connect

    Prodi, L.; Gandolfi, M.T.; Balzani, V. ); Ballardini, R. ); Desvergne, J.P.; Bouas-Laurent, H. )

    1991-03-07

    Pt(bpy)(NH{sub 3}){sub 2}{sup 2+} forms a 1:1 adduct with the anthraceno-crown ether 2. The adduct formation causes (i) strong changes in the absorption spectra of the two components, (ii) the quenching of the luminescence and photoreactivity of both Pt(bpy)(NH{sub 3}){sub 2}{sup 2+} and 2, and (iii) the appearance of a new, broad, low-energy emission band at 77 K. It is suggested that the adduct exhibits a sandwich-type conformation in which the Pt complex is inserted between the two aromatic moieties of 2. Such a structure allows the stabilization of the adduct via both hydrogen bonds and {pi}-{pi} interactions and accounts for the mutual protection of the two components toward their luminescence and photoreactivity.

  1. An evaluation of the mutagenicity, metabolism, and DNA adduct formation of 5-nitrobenzo[b]naphtho[2,1-d]thiophene.

    PubMed

    King, L C; Kohan, M J; Brooks, L; Nelson, G B; Ross, J A; Allison, J; Adams, L; Desai, D; Amin, S; Padgett, W; Lambert, G R; Richard, A M; Nesnow, S

    2001-06-01

    Thioarenes, sulfur-containing polycyclic aromatic compounds, are environmental contaminants suspected of posing human health risks. In this study, 5-nitrobenzo[b]naphtho[2,1-d]thiophene (5-nitro-BNT), a nitrated-thioarene, was examined for its mutagenicity, metabolism and subsequent formation of DNA adducts. 5-Nitro-BNT was weakly mutagenic in Salmonella typhimurium strains TA98 and TA100 without Aroclor-1254-induced rat liver S9 (S9), and its activity was increased in the presence of S9. Anaerobic metabolism of 5-nitro-BNT by S9 or xanthine oxidase (XO) produced one major metabolite, identified as 5-amino-BNT by NMR, MS, and UV spectroscopy and by comparison with an authentic standard. Aerobic S9 metabolism of 5-nitro-BNT produced a major metabolite, identified as trans-9,10-dihydroxy-9,10-dihydro-5-nitro-BNT (5-nitro-BNT-9,10-diol). Also present was a minor amount of 5-amino-BNT and trans-9,10-dihydroxy-9,10-dihydro-5-amino-BNT (5-amino-BNT-9,10-diol). DNA adduct analyses were performed using the (32)P-postlabeling assay and reversed-phase HPLC. Three major XO-derived calf thymus DNA adducts were detected. On the basis of their chromatographic mobilities, two adducts were identified as reaction products of 5-nitro-BNT with 2'-deoxyguanosine and one adduct with 2'-deoxyadenosine. Incorporation of allopurinol (a specific XO inhibitor) in the incubation mixture resulted in loss of all three adducts, confirming enzymatic mediation by XO. Aerobic S9 activation of 5-nitro-BNT with calf thymus DNA produced three adducts. On the basis of their chromatographic mobilities, two were identified as reaction products of 5-nitro-BNT with 2'-deoxyguanosine and one with 2'-deoxyadenosine. Incorporation of 1-aminobenzotriazole (a P450 inhibitor) in the incubation mixture resulted in a loss of these adducts, confirming enzymatic mediation by P450. Aerobic S9-catalyzed metabolism of 5-nitro-BNT-9,10-diol produced the same DNA adducts as observed with 5-nitro-BNT. Aerobic S9

  2. Development of an immunoassay to detect benzene adducts in hemoglobin

    SciTech Connect

    Grassman, J.A.

    1993-01-01

    The purpose of this project was to develop an immunoassay to detect the adducts formed in hemoglobin after exposure to benzene, which is known to cause bone marrow degeneration and acute myelogenous leukemia. The use of benzene-adduct detection as a biological monitoring method would permit measurement of low exposures and exposures sustained weeks earlier. The reactivity of hydroquinone, an important benzene metabolite, with blood proteins and amino acids was investigated in order to decide which antigens and analytes were likely to be suitable for immunoassay development. The second section determined the combination of benzene-metabolite and antigen need to produce an immunoassay with the requisite low detection limit and specificity. The immunoassays with the best performance were tested on hemoglobin from benzene-exposed mice. In vitro studies showed that hydroquinone efficiently formed adducts with erythrocyte membranes and hemoglobin but not with albumin. Adduction efficiency was greater in incubations using purified hemoglobin than whole blood. Cysteine accounted for 15 to 27% of the adducts formed by hydroquinone. The site of the other adducts were not identified although there was evidence that the hemoglobin heme was adducted. Adducts were found on only 1 of the 2 globin chains. Tryptic digestion of the globin failed to associate the adducts with a specific peptide. Antigens made from hydroquinone-adducted hemoglobin but not hydroquinone-adducted cysteines coupled to carrier proteins effectively elicited adduct-specific antibodies. Interference due to reactivity to hemoglobin was controlled by using uniform quantities of hemoglobin in all wells. The mid-range of the best assays were approximately 12 pmoles HQ per well. Antibodies directed toward hemoglobin adducted with the benzene metabolites phenol, catechol and 1,2,4-trihydroxybenzene were also made. The performance of the anti-1,2,4-trihydroxybenzene were suitable for quantitative immunoassays.

  3. The influence of isometric hip adduction on quadriceps femoris activity.

    PubMed

    Hodges, P W; Richardson, C A

    1993-06-01

    In the treatment of muscle imbalances around the knee, hip adduction and the contraction of adductor magnus have been used to facilitate vastus medialis obliquus (VMO) to a greater extent than vastus lateralis (VL). This study was conducted to investigate the effectiveness of this technique. Hip adduction was superimposed onto the contraction of quadriceps femoris in a weight bearing (WB) and a non-weight bearing (NWB) position at three levels of hip adduction force. The muscle activity of VMO and VL was recorded using electromyography with the ratio of the recordings of VMO to VL used for comparison. The activity of VMO compared with VL was greater in WB than NWB without hip adduction. VMO activity increased relatively more than VL with the addition of each level of hip adduction in WB and only with maximal hip adduction in NWB. The results provide support for the use of this technique.

  4. Infrared spectra of some acetone—magnesium adducts

    NASA Astrophysics Data System (ADS)

    Hisatsune, I. C.

    Co-deposition of atomic magnesium with excess acetone at liquid-nitrogen temperature produces an unstable charge-transfer complex with a characteristic carbonyl infrared band at 1595 cm -1 and stable acetone adducts in which the metal atom bridges the carbonyl bond (π-complex) or coordinates to the oxygen atom (σ-complex). Infrared spectra of these complexes with (CH 3) 2CO and (CD 3) 2CO have been obtained. Corroborations for these adducts were obtained from infrared studies of acetone matrices with atomic copper and acetaldehyde matrices with atomic magnesium and with atomic copper. Infrared spectra of an acetone adduct and a dimethyl ether adduct of the Grignard reagent CH 3MgI have also been obtained. Hydrolysis of a σ-adduct gives acetone but isopropyl alcohol is obtained from hydrolysis of the π-adduct.

  5. Protein modification by acrolein: Formation and stability of cysteine adducts

    PubMed Central

    Cai, Jian; Bhatnagar, Aruni; Pierce, William M.

    2010-01-01

    The toxicity of the ubiquitous pollutant and endogenous metabolite, acrolein, is due in part to covalent protein modifications. Acrolein reacts readily with protein nucleophiles via Michael addition and Schiff base formation. Potential acrolein targets in protein include the nucleophilic side chains of cysteine, histidine, and lysine residues as well as the free amino terminus of proteins. Although cysteine is the most acrolein-reactive residue, cysteine-acrolein adducts are difficult to identify in vitro and in vivo. In this study, model peptides with cysteine, lysine, and histidine residues were used to examine the reactivity of acrolein. Results from these experiments show that acrolein reacts rapidly with cysteine residues through Michael addition to form M+56 Da adducts. These M+56 adducts are, however, not stable, even though spontaneous dissociation of the adduct is slow. Further studies demonstrated that when acrolein and model peptides are incubated at physiological pH and temperature, the M+56 adducts decreased gradually accompanied by the increase of M+38 adducts, which are formed from intra-molecular Schiff base formation. Adduct formation with the side chains of other amino acid residues (lysine and histidine) was much slower than cysteine and required higher acrolein concentration. When cysteine residues were blocked by reaction with iodoacetamide and higher concentrations of acrolein were used, adducts of the N-terminal amino group or histidyl residues were formed but lysine adducts were not detected. Collectively, these data demonstrate that acrolein reacts avidly with protein cysteine residues and that the apparent loss of protein-acrolein Michael adducts over time may be related to the appearance of a novel (M+38) adduct. These findings may be important in identification of in vivo adducts of acrolein with protein cysteine residues. PMID:19231900

  6. Role of malondialdehyde-acetaldehyde adducts in liver injury.

    PubMed

    Tuma, Dean J

    2002-02-15

    Malondialdehyde and acetaldehyde react together with proteins in a synergistic manner and form hybrid protein adducts, designated as MAA adducts. MAA-protein adducts are composed of two major products whose structures and mechanism of formation have been elucidated. MAA adduct formation, especially in the liver, has been demonstrated in vivo during ethanol consumption. These protein adducts are capable of inducing a potent immune response, resulting in the generation of antibodies against both MAA epitopes, as well as against epitopes on the carrier protein. Chronic ethanol administration to rats results in significant circulating antibody titers against MAA-adducted proteins, and high anti-MAA titers have been associated with the severity of liver damage in humans with alcoholic liver disease. In vitro exposure of liver endothelial or hepatic stellate cells to MAA adducts induces a proinflammatory and profibrogenic response in these cells. Thus, during excessive ethanol consumption, ethanol oxidation and ethanol-induced oxidative stress result in the formation of acetaldehyde and malondialdehyde, respectively. These aldehydes can react together synergistically with proteins and generate MAA adducts, which are very immunogenic and possess proinflammatory and profibrogenic properties. By virtue of these potentially toxic effects, MAA adducts may play an important role in the pathogenesis of alcoholic liver injury.

  7. What predicts the first peak of the knee adduction moment?

    PubMed Central

    Schmitz, Anne; Noehren, Brian

    2014-01-01

    Introduction The first peak of the knee adduction moment curve during walking has been shown to be a good clinical surrogate measure of medial tibiofemoral joint loading and osteoarthritis. Defining the relative contributions of the variables that dictate the knee adduction moment, such as center of mass, center of pressure, vertical ground reaction force, and knee adduction angle (i.e. lower limb alignment), has not been formally investigated within the same cohort of individuals. Purpose Therefore, the goal of this study was to determine which of these variables is the biggest determinant of the first peak of knee adduction moment curve. Methods Instrumented gait analysis was collected for 30 individuals. Variables significantly correlated with the peak knee adduction moment were input into a stepwise multi-variable linear regression model. Results The knee adduction angle predicted 58% of the variance in the first peak knee adduction moment and the vertical ground reaction force magnitude predicted the second most variance (20%). Conclusions The most effective way to modify the peak knee adduction moment may be to change the knee adduction angle (e.g. offloader brace), followed by changing the vertical magnitude of the ground reaction force (e.g. cane use). PMID:25127390

  8. Electrospray ionization mass spectrometric characterization of acrylamide adducts to hemoglobin

    SciTech Connect

    Springer, D.L.; Goheen, S.C.; Edmonds, C.G. ); Bull, R.J.; Sylvester, D.M. )

    1993-01-01

    The most common procedure to identify hemoglobin adducts has been to cleave the adducts from the protein and characterize the adducting species, by, for example, derivatization and gas chromatography/mass spectrometry. To extend these approaches we used electrospray ionization mass spectrometry (ESI-MS) to characterize adducted hemoglobin. For this we incubated [[sup 14]C]acrylamide with the purified human hemoglobin (type A[sub 0]) under conditions that yielded high adduct levels. When the hemoglobin was separated by reversed-phase high-performance liquid chromatography (HPLC), 65% of the radioactivity copurified with the [beta]-subunit. Three adducted species were prominent in the ESI mass spectrum of the intact [beta]-subunit, indicating acrylamide adduction (i.e., mass increase of 71 Da) and two addition unidentified moieties with mass increments of 102 and 135 Da. Endoproteinase Glu-C digestion of the adducted [beta]-subunit resulted in a peptide mixture that, upon reversed-phase HPLC separation, provided several radiolabeled peptides. Using ESI-MS we identified these as the V[sub 91-101] and V[sub 102-122] peptides that represent the cysteine-containing peptides of the [beta]-subunit. These results provide definitive information on acrylamide-modified human hemoglobin and demonstrate that ESI-MS provides valuable structure information on chemically adducted proteins. 30 refs., 9 figs., 3 tabs.

  9. Quantitation of carcinogen bound protein adducts by fluorescence measurements

    NASA Astrophysics Data System (ADS)

    Gan, Liang-Shang; Otteson, Michael S.; Doxtader, Mark M.; Skipper, Paul L.; Dasari, Ramachandra R.; Tannenbaum, Steven R.

    1989-01-01

    A highly significant correlation of aflatoxin B 1 serum albumin adduct level with daily aflatoxin B 1 intake was observed in a molecular epidemiological study of aflatoxin carcinogenesis which used conventional fluorescence spectroscopy methods for adduct quantitation. Synchronous fluorescence spectroscopy and laser induced fluorescence techniques have been employed to quantitate antibenzo[ a]pyrene diol epoxide derived globin peptide adducts. Fast and efficient methods to isolate the peptide adducts as well as eliminate protein fluorescence background are described. A detection limit of several femtomoles has been achieved. Experimental and technical considerations of low temperature synchronous fluorescence spectroscopy and fluorescence line narrowing to improve the detection sensitivities are also presented.

  10. Interaction of benzo[a]pyrene diol epoxide isomers with human serum albumin: Site specific characterisation of adducts and associated kinetics

    NASA Astrophysics Data System (ADS)

    Motwani, Hitesh V.; Westberg, Emelie; Törnqvist, Margareta

    2016-11-01

    Carcinogenicity of benzo[a]pyrene {B[a]P, a polycyclic aromatic hydrocarbon (PAH)} involves DNA-modification by B[a]P diol epoxide (BPDE) metabolites. Adducts to serum albumin (SA) are not repaired, unlike DNA adducts, and therefore considered advantageous in assessment of in vivo dose of BPDEs. In the present work, kinetic experiments were performed in relation to the dose (i.e. concentration over time) of different BPDE isomers, where human SA (hSA) was incubated with respective BPDEs under physiological conditions. A liquid chromatography (LC) tandem mass spectrometry methodology was employed for characterising respective BPDE-adducts at histidine and lysine. This strategy allowed to structurally distinguish between the adducts from racemic anti- and syn-BPDE and between (+)- and (-)-anti-BPDE, which has not been attained earlier. The adduct levels quantified by LC-UV and the estimated rate of disappearance of BPDEs in presence of hSA gave an insight into the reactivity of the diol epoxides towards the N-sites on SA. The structure specific method and dosimetry described in this work could be used for accurate estimation of in vivo dose of the BPDEs following exposure to B[a]P, primarily in dose response studies of genotoxicity, e.g. in mice, to aid in quantitative risk assessment of PAHs.

  11. Interaction of benzo[a]pyrene diol epoxide isomers with human serum albumin: Site specific characterisation of adducts and associated kinetics

    PubMed Central

    Motwani, Hitesh V.; Westberg, Emelie; Törnqvist, Margareta

    2016-01-01

    Carcinogenicity of benzo[a]pyrene {B[a]P, a polycyclic aromatic hydrocarbon (PAH)} involves DNA-modification by B[a]P diol epoxide (BPDE) metabolites. Adducts to serum albumin (SA) are not repaired, unlike DNA adducts, and therefore considered advantageous in assessment of in vivo dose of BPDEs. In the present work, kinetic experiments were performed in relation to the dose (i.e. concentration over time) of different BPDE isomers, where human SA (hSA) was incubated with respective BPDEs under physiological conditions. A liquid chromatography (LC) tandem mass spectrometry methodology was employed for characterising respective BPDE-adducts at histidine and lysine. This strategy allowed to structurally distinguish between the adducts from racemic anti- and syn-BPDE and between (+)- and (−)-anti-BPDE, which has not been attained earlier. The adduct levels quantified by LC-UV and the estimated rate of disappearance of BPDEs in presence of hSA gave an insight into the reactivity of the diol epoxides towards the N-sites on SA. The structure specific method and dosimetry described in this work could be used for accurate estimation of in vivo dose of the BPDEs following exposure to B[a]P, primarily in dose response studies of genotoxicity, e.g. in mice, to aid in quantitative risk assessment of PAHs. PMID:27805056

  12. Comparison of mutagenicity and calf thymus DNA adducts formed by the particulate and semivolatile fractions of vehicle exhausts.

    PubMed

    Pohjola, Sanna K; Lappi, Maija; Honkanen, Markku; Savela, Kirsti

    2003-01-01

    In this study we compared the ability of extractable organic material from particulate and semivolatile fractions of gasoline emission to induce mutations in bacteria and form adducts with calf thymus (CT) DNA with corresponding data obtained from diesel exhaust. Exhaust particles from gasoline-powered passenger cars were collected on filters and semivolatile compounds were collected on polyurethane foam (PUF). The mutagenicity of the soluble organic fraction (SOF) was determined in Salmonella typhimurium strain TA98 and the DNA binding of aromatic compounds in the extracts was assessed by in vitro incubations with CT DNA and rat liver S9 (oxidative activation) or xanthine oxidase (reductive activation) followed by butanol-enhanced (32)P-postlabeling analysis. Semivolatile fractions of gasoline emission collected on PUF formed more CT DNA adducts than filter extracts under all reaction conditions, but showed a lower mutagenic potential than the corresponding particulate samples. This suggests that the capacity of PUF to collect exhaust particle-derived compounds and/or the efficiency of xanthine oxidase and enzymes in the rat liver S9 to activate these compounds to DNA binding metabolites was higher than expected. Gasoline extracts, benzo[a]pyrene and diesel particulate matter (SRM 1650) formed more S9-mediated DNA adducts as their dose increased, although a linear dose-response was not observed for the gasoline exhausts. Lower concentrations of gasoline and diesel extracts bound to DNA with greater efficiency than did 8-fold higher doses, suggesting complex interactions and/or an inhibition of S9 enzyme activities by the high doses. Diesel extracts formed higher levels of adducts than gasoline extracts, especially with the reductive activation system, suggesting that diesel extracts contain high levels of nitro-polycyclic aromatic hydrocarbons (nitro-PAHs). The higher direct-acting Salmonella mutagenicity in diesel extracts in comparison with gasoline extracts is

  13. Xenobiotic metabolism induction and bulky DNA adducts generated by particulate matter pollution in BEAS-2B cell line: geographical and seasonal influence.

    PubMed

    Lepers, Capucine; André, Véronique; Dergham, Mona; Billet, Sylvain; Verdin, Anthony; Garçon, Guillaume; Dewaele, Dorothée; Cazier, Fabrice; Sichel, François; Shirali, Pirouz

    2014-06-01

    Airborne particulate matter (PM) toxicity is of growing interest as diesel exhaust particles have been classified as carcinogenic to humans. However, PM is a mixture of chemicals, and respective contribution of organic and inorganic fractions to PM toxicity remains unclear. Thus, we analysed the link between chemical composition of PM samples and bulky DNA adduct formation supported by CYP1A1 and 1B1 genes induction and catalytic activities. We used six native PM samples, collected in industrial, rural or urban areas, either during the summer or winter, and carried out our experiments on the human bronchial epithelial cell line BEAS-2B. Cell exposure to PM resulted in CYP1A1 and CYP1B1 genes induction. This was followed by an increase in EROD activity, leading to bulky DNA adduct formation in exposed cells. Bulky DNA adduct intensity was associated to global EROD activity, but this activity was poorly correlated with CYPs mRNA levels. However, EROD activity was correlated with both metal and polycyclic aromatic hydrocarbon (PAH) content. Finally, principal components analysis revealed three clusters for PM chemicals, and suggested synergistic effects of metals and PAHs on bulky DNA adduct levels. This study showed the ability of PM samples from various origins to generate bulky DNA adducts in BEAS-2B cells. This formation was promoted by increased expression and activity of CYPs involved in PAHs activation into reactive metabolites. However, our data highlight that bulky DNA adduct formation is only partly explained by PM content in PAHs, and suggest that inorganic compounds, such as iron, may promote bulky DNA adduct formation by supporting CYP activity.

  14. Biomarkers for exposure to ambient air pollution--comparison of carcinogen-DNA adduct levels with other exposure markers and markers for oxidative stress.

    PubMed

    Autrup, H; Daneshvar, B; Dragsted, L O; Gamborg, M; Hansen, M; Loft, S; Okkels, H; Nielsen, F; Nielsen, P S; Raffn, E; Wallin, H; Knudsen, L E

    1999-03-01

    Human exposure to genotoxic compounds present in ambient air has been studied using selected biomarkers in nonsmoking Danish bus drivers and postal workers. A large interindividual variation in biomarker levels was observed. Significantly higher levels of bulky carcinogen-DNA adducts (75.42 adducts/10(8) nucleotides) and of 2-amino-apidic semialdehyde (AAS) in plasma proteins (56.7 pmol/mg protein) were observed in bus drivers working in the central part of Copenhagen, Denmark. In contrast, significantly higher levels of AAS in hemoglobin (55.8 pmol/mg protein), malondialdehyde in plasma (0. 96 nmol/ml plasma), and polycyclic aromatic hydrocarbon (PAH)-albumin adduct (3.38 fmol/ microg albumin) were observed in the suburban group. The biomarker levels in postal workers were similar to the levels in suburban bus drivers. In the combined group of bus drivers and postal workers, negative correlations were observed between bulky carcinogen-DNA adduct and PAH-albumin levels (p = 0.005), and between DNA adduct and [gamma]-glutamyl semialdehyde (GGS) in hemoglobin (p = 0.11). Highly significant correlations were found between PAH-albumin adducts and AAS in plasma (p = 0.001) and GGS in hemoglobin (p = 0.001). Significant correlations were also observed between urinary 8-oxo-7, 8-dihydro-2'-deoxyguanosine and AAS in plasma (p = 0.001) and PAH-albumin adducts (p = 0.002). The influence of the glutatione S-transferase (GST) M1 deletion on the correlation between the biomarkers was studied in the combined group. A significant negative correlation was only observed between bulky carcinogen-DNA adducts and PAH-albumin adducts (p = 0.02) and between DNA adduct and urinary mutagenic activity (p = 0.02) in the GSTM1 null group, but not in the workers who were homozygotes or heterozygotes for GSTM1. Our results indicate that some of the selected biomarkers can be used to distinguish between high and low exposure to environmental genotoxins.

  15. Bulky DNA Adducts in Cord Blood, Maternal Fruit-and-Vegetable Consumption, and Birth Weight in a European Mother–Child Study (NewGeneris)

    PubMed Central

    Schoket, Bernadette; Godschalk, Roger W.; Wright, John; von Stedingk, Hans; Törnqvist, Margareta; Sunyer, Jordi; Nielsen, Jeanette K.; Merlo, Domenico F.; Mendez, Michelle A.; Meltzer, Helle M.; Lukács, Viktória; Landström, Anette; Kyrtopoulos, Soterios A.; Kovács, Katalin; Knudsen, Lisbeth E.; Haugen, Margaretha; Hardie, Laura J.; Gützkow, Kristine B.; Fleming, Sarah; Fthenou, Eleni; Farmer, Peter B.; Espinosa, Aina; Chatzi, Leda; Brunborg, Gunnar; Brady, Nigel J.; Botsivali, Maria; Arab, Khelifa; Anna, Lívia; Alexander, Jan; Agramunt, Silvia; Kleinjans, Jos C.; Segerbäck, Dan; Kogevinas, Manolis

    2013-01-01

    Background: Tobacco-smoke, airborne, and dietary exposures to polycyclic aromatic hydrocarbons (PAHs) have been associated with reduced prenatal growth. Evidence from biomarker-based studies of low-exposed populations is limited. Bulky DNA adducts in cord blood reflect the prenatal effective dose to several genotoxic agents including PAHs. Objectives: We estimated the association between bulky DNA adduct levels and birth weight in a multicenter study and examined modification of this association by maternal intake of fruits and vegetables during pregnancy. Methods: Pregnant women from Denmark, England, Greece, Norway, and Spain were recruited in 2006–2010. Adduct levels were measured by the 32P-postlabeling technique in white blood cells from 229 mothers and 612 newborns. Maternal diet was examined through questionnaires. Results: Adduct levels in maternal and cord blood samples were similar and positively correlated (median, 12.1 vs. 11.4 adducts in 108 nucleotides; Spearman rank correlation coefficient = 0.66, p < 0.001). Cord blood adduct levels were negatively associated with birth weight, with an estimated difference in mean birth weight of –129 g (95% CI: –233, –25 g) for infants in the highest versus lowest tertile of adducts. The negative association with birth weight was limited to births in Norway, Denmark, and England, the countries with the lowest adduct levels, and was more pronounced in births to mothers with low intake of fruits and vegetables (–248 g; 95% CI: –405, –92 g) compared with those with high intake (–58 g; 95% CI: –206, 90 g) Conclusions: Maternal exposure to genotoxic agents that induce the formation of bulky DNA adducts may affect intrauterine growth. Maternal fruit and vegetable consumption may be protective. Citation: Pedersen M, Schoket B, Godschalk RW, Wright J, von Stedingk H, Törnqvist M, Sunyer J, Nielsen JK, Merlo DF, Mendez MA, Meltzer HM, Lukács V, Landström A, Kyrtopoulos SA, Kovács K, Knudsen LE, Haugen

  16. Molecular catalytic hydrogenation of aromatic hydrocarbons and hydrotreating of coal liquids.

    SciTech Connect

    Yang, Shiyong; Stock, L.M.

    1996-05-01

    This report presents the results of research on the development of new catalytic pathways for the hydrogenation of multiring aromatic hydrocarbons and the hydrotreating of coal liquids at The University of Chicago under DOE Contract No. DE-AC22-91PC91056. The work, which is described in three parts, is primarily concerned with the research on the development of new catalytic systems for the hydrogenation of aromatic hydrocarbons and for the improvement of the quality of coal liquids by the addition of dihydrogen. Part A discusses the activation of dihydrogen by very basic molecular reagents to form adducts that can facilitate the reduction of multiring aromatic hydrocarbons. Part B examines the hydrotreating of coal liquids catalyzed by the same base-activated dihydrogen complexes. Part C concerns studies of molecular organometallic catalysts for the hydrogenation of monocyclic aromatic hydrocarbons under mild conditions.

  17. Selective Aromatic C–H Hydroxylation Enabled by η6-Coordination to Iridium(III)

    PubMed Central

    D'Amato, Erica M.; Neumann, Constanze N.; Ritter, Tobias

    2016-01-01

    We report an aromatic C–H hydroxylation protocol in which the arene is activated through η6-coordination to an iridium(III) complex. η6-Coordination of the arene increases its electrophilicity and allows for high positional selectivity of hydroxylation at the site of least electron density. Through investigation of intermediate η5-cyclohexadienyl adducts and arene exchange reactions, we evaluate incorporation of arene π-activation into a catalytic cycle for C–H functionalization. PMID:26877574

  18. PURIFICATION AND RECOVERY OF BULKY HYDROPHOBIC DNA ADDUCTS

    EPA Science Inventory

    For many years 32P postlabeling has detected DNA adducts at very low levels and yet has not been able to identify unknown adducts. Mass spectrometry offers substantially improved identification powers, albeit at some loss in detection limits. With this ultimate utilization of ma...

  19. The antimicrobial activities of the cinnamaldehyde adducts with amino acids.

    PubMed

    Wei, Qing-Yi; Xiong, Jia-Jun; Jiang, Hong; Zhang, Chao; Wen Ye

    2011-11-01

    Cinnamaldehyde is a well-established natural antimicrobial compound. It is probable for cinnamaldehyde to react with amino acid forming Schiff base adduct in real food system. In this paper, 9 such kind of adducts were prepared by the direct reaction of amino acids with cinnamaldehyde at room temperature. Their antimicrobial activities against Bacillus subtilis, Escherichia coli and Saccharomyces cerevisiae were evaluated with benzoic acid as a reference. The adducts showed a dose-dependent activities against the three microbial strains. Both cinnamaldehyde and their adducts were more active against B. subtilis than on E. coli, and their antimicrobial activities were higher at lower pH. Both cinnamaldehyde and its adducts were more active than benzoic acid at the same conditions. The adduct compound A was non-toxic by primary oral acute toxicity study in mice. However, in situ effect of the adduct compound A against E. coli was a little lower than cinnamaldehyde in fish meat. This paper for the first time showed that the cinnamaldehyde adducts with amino acids had similar strong antimicrobial activities as cinnamaldehyde, which may provide alternatives to cinnamaldehyde in food to avoid the strong unacceptable odor of cinnamaldehyde. Copyright © 2010 Elsevier B.V. All rights reserved.

  20. Relationship between DNA adduct formation and unscheduled DNA synthesis (UDS) in cultured mouse epidermal keratinocytes

    SciTech Connect

    Gill, R.D.; Nettikumara, A.N.; DiGiovanni, J. ); Butterworth, B.E. )

    1991-01-01

    Primary cultures of mouse epidermal keratinocytes from SENCAR mice were treated with 7,12-dimethylbenz(a)anthracene (DMBA), benzo(a)pyrene (B(a)P), ({plus minus}) 7{beta}-8{alpha}-dihydroxy-9{alpha},10{alpha}-epoxy-7,8,9,10-tetrahydrobenzo(a)pyrene (({plus minus}) anti-BPDE), and ({plus minus}) 7{beta},8{alpha}-dihydroxy-9{beta},10{beta}-epoxy-7,8,9,10-tetrahydrobenzo(a)pyrene (({plus minus})syn-BPDE) to examine the relationship between DNA adduct formation and the induction of unscheduled DNA synthesis (UDS). DNA adducts were measured as pmol hydrocarbon bound per mg of DNA, and UDS was quantitated autoradiographically as net grains per nucleus. A good correlation was observed between the levels of UDS detected and the amount of DNA adducts present int he cell population when comparing similar compounds within the linear dose-response range of 0.005 {mu}g/ml-0.25 {mu}g/ml. These results suggest that the present UDS assay with MEKs is a useful assay for the rapid screening of potential genotoxic agents. However, the limits of sensitivity are such that the current assay may be unable to detect a low level of DNA damage induced by some weakly genotoxic (carcinogenic) agents. In addition, while the limits of sensitivity determined in these experiments apply to the polycyclic aromatic hydrocarbon class, other classes of genotoxic compounds such as alkylating agents or crosslinking agents may exhibit different thresholds of detection.

  1. [Preliminary study on naphthalene-metabolites-albumin adduct as an exposure biomarker for coke oven workers].

    PubMed

    Dai, Yu-fei; Leng, Shu-guang; Pan, Zu-fei; Rappaport, Stephen M; Zheng, Yu-xin

    2004-11-01

    To study albumin adduct with naphthalene metabolites, namely 1,2-naphthoquinone (1,2-NPQ) and 1,4-naphthoquinone (1,4-NPQ), as a potential biomarker for intermediate/long-term exposure to polycyclic aromatic hydrocarbons (PAH) in coke oven workers. Twenty-eight coke oven workers and 22 control workers were recruited from a cokery. Spot urine and venous blood samples were collected from the workers after four continuously working days and personal information was obtained by questionnaire. Plasma albumin adduct was detected with gas chromatography-mass spectrometry. Albumin adduct with 1,2- & 1,4-NPQ (1,2-NPQ and 1,4-NPQ), respectively, were detected in all coke oven workers and controls. Median plasma level of 1,2-NPQ-Alb in coke oven workers was significantly higher than that in controls (76.6 pmol/g vs. 44.9 pmol/g, P < 0.01). However, there was no significant difference in plasma median level of 1,4-NPQ-Alb between the two groups (48.6 pmol/g vs. 44.2 pmol/g, P > 0.05). Plasma level of 1,2-NPQ-Alb was significantly higher than that of 1,4-NPQ-Alb in coke oven workers. Urine levels of naphthalene, 1-naphthol, 2-naphthol and 1-pyrenol in coke oven workers correlated significantly with their plasma level of 1,2-NPQ-Alb (Pearson coefficient of correlation greater than 0.371, P < 0.01), but did not do significantly with 1,4-NPQ-Alb. Plasma level of 1,2-NPQ-Alb could effectively reflect their magnitude of personal internal dose of exposure to air PAH, so it could be used as a potential biomarker to evaluate their intermediate/long-term exposure to PAH in coke oven workers.

  2. Adduct Formation in ESI/MS by Mobile Phase Additives

    NASA Astrophysics Data System (ADS)

    Kruve, Anneli; Kaupmees, Karl

    2017-03-01

    Adduct formation is a common ionization method in electrospray ionization mass spectrometry (ESI/MS). However, this process is poorly understood and complicated to control. We demonstrate possibilities to control adduct formation via mobile phase additives in ESI positive mode for 17 oxygen and nitrogen bases. Mobile phase additives were found to be a very effective measure for manipulating the formation efficiencies of adducts. An appropriate choice of additive may increase sensitivity by up to three orders of magnitude. In general, sodium adduct [M + Na]+ and protonated molecule [M + H]+ formation efficiencies were found to be in good correlation; however, the former were significantly more influenced by mobile phase properties. Although the highest formation efficiencies for both species were observed in water/acetonitrile mixtures not containing additives, the repeatability of the formation efficiencies was found to be improved by additives. It is concluded that mobile phase additives are powerful, yet not limiting factors, for altering adduct formation.

  3. Adduct Formation in ESI/MS by Mobile Phase Additives

    NASA Astrophysics Data System (ADS)

    Kruve, Anneli; Kaupmees, Karl

    2017-05-01

    Adduct formation is a common ionization method in electrospray ionization mass spectrometry (ESI/MS). However, this process is poorly understood and complicated to control. We demonstrate possibilities to control adduct formation via mobile phase additives in ESI positive mode for 17 oxygen and nitrogen bases. Mobile phase additives were found to be a very effective measure for manipulating the formation efficiencies of adducts. An appropriate choice of additive may increase sensitivity by up to three orders of magnitude. In general, sodium adduct [M + Na]+ and protonated molecule [M + H]+ formation efficiencies were found to be in good correlation; however, the former were significantly more influenced by mobile phase properties. Although the highest formation efficiencies for both species were observed in water/acetonitrile mixtures not containing additives, the repeatability of the formation efficiencies was found to be improved by additives. It is concluded that mobile phase additives are powerful, yet not limiting factors, for altering adduct formation.

  4. Biomarkers of polycyclic aromatic hydrocarbon exposure in European coke oven workers.

    PubMed

    Talaska, Glenn; Thoroman, Jeff; Schuman, Brenda; Käfferlein, Heiko Udo

    2014-12-01

    Biomonitoring is an excellent method for capturing the results of all exposures, regardless of route. Coke oven workers include certain groups that have the potential for high exposure to polycyclic aromatic hydrocarbons (PAH) and other materials. Biomarkers of exposure to these agents include PAH metabolites as markers of internal dose and carcinogen-DNA adducts as measure of effective dose. The purpose of this study was to determine the levels of these biomarkers in persons with different job duties in a modern coke oven plant. We report that the mean levels of 1-hydroxypyrene (1HP) and carcinogen DNA adducts in the exfoliated urothelial cells of coke oven workers are increased the closer a group of workers is to the ovens and highest in the top oven workers with average 1HP level of 11.6 μg/l and 22 adducts per 10(9) unadducted nucleotides. Both 1HP and carcinogen DNA adduct levels increased in supervisors, area workers, side oven workers, top and side oven workers, and top oven workers, respectively. These data are the first to demonstrate an increase in target organ genotoxicity in coke oven workers and a relationship with other biomarkers. Future studies will determine the identity of the DNA adducts, their correlation with 1HP levels and the relationship between levels in individual workers.

  5. Nucleophilic Aromatic Substitution.

    ERIC Educational Resources Information Center

    Avila, Walter B.; And Others

    1990-01-01

    Described is a microscale organic chemistry experiment which demonstrates one feasible route in preparing ortho-substituted benzoic acids and provides an example of nucleophilic aromatic substitution chemistry. Experimental procedures and instructor notes for this activity are provided. (CW)

  6. Nucleophilic Aromatic Substitution.

    ERIC Educational Resources Information Center

    Avila, Walter B.; And Others

    1990-01-01

    Described is a microscale organic chemistry experiment which demonstrates one feasible route in preparing ortho-substituted benzoic acids and provides an example of nucleophilic aromatic substitution chemistry. Experimental procedures and instructor notes for this activity are provided. (CW)

  7. The Formation and Biological Significance of N7-Guanine Adducts

    PubMed Central

    Boysen, Gunnar; Pachkowski, Brian F.; Nakamura, Jun; Swenberg, James A

    2009-01-01

    DNA alkylation or adduct formation occurs at nucleophilic sites in DNA, mainly the N7-position of guanine. Ever since identification of the first N7-guanine adduct, several hundred studies on DNA adducts have been reported. Major issues addressed include the relationships between N7-guanine adducts and exposure, mutagenesis, and other biological endpoints. It became quickly apparent that N7-guanine adducts are frequently formed, but may have minimal biological relevance, since they are chemically unstable and do not participate in Watson Crick base pairing. However, N7-guanine adducts have been shown to be excellent biomarkers for internal exposure to direct acting and metabolically activated carcinogens. Questions arise, however, regarding the biological significance for N7-guanine adducts that are readily formed, do not persist, and are not likely to be mutagenic. Thus, we set out to review the current literature to evaluate their formation and the mechanistic evidence for the involvement of N7-guanine adducts in mutagenesis or other biological processes. It was concluded that there is insufficient evidence that N7-guanine adducts can be used beyond confirmation of exposure to the target tissue and demonstration of the molecular dose. There is little to no evidence that N7-guanine adducts or their depurination product, apurinic sites, are the cause of mutations in cells and tissues, since increases in AP sites have not been shown unless toxicity is extant. However, more research is needed to define the extent of chemical depurination versus removal by DNA repair proteins. Interestingly, N7-guanine adducts are clearly present as endogenous background adducts and the endogenous background amounts appear to increase with age. Furthermore, the N7-guanine adducts have been shown to convert to ring opened lesions (FAPy), which are much more persistent and have higher mutagenic potency. Studies in humans are limited in sample size and differences between controls and

  8. Immunofluorescent detection of 8-oxo-dG and PAH bulky adducts in fish liver and mussel digestive gland.

    PubMed

    Machella, Nicola; Regoli, Francesco; Santella, Regina M

    2005-03-04

    Development of methodologies to detect DNA damage induced by pollutants is of increasing concern in marine ecotoxicology. We previously described an immunoperoxidase method for revealing 7,8-dihydro-8-oxodeoxyguanosine (8-oxo-dG) in marine organisms. In this work, the approach was extended to immunofluorescence detection and to the use of another antibody for polycyclic aromatic hydrocarbon (PAH)-DNA adducts. Specimens of European eel (Anguilla anguilla) and Mediterranean mussel (Mytilus galloprovincialis) were exposed to benzo(a)pyrene (B[a]P), as model chemical carcinogen to induce both oxidized bases and B[a]P diol-epoxide-deoxyguanosine adducts. Cryostat sections of liver and digestive gland from both species were immunostained, and DNA damage was semiquantitatively evaluated by an image analysis system. Compared to untreated organisms, B[a]P-exposed organisms exhibited increased levels of oxidative DNA damage; in eels, which rapidly metabolize PAHs, the occurrence of B[a]P-DNA adducts was also detected. The immunofluorescent assay maintained all the advantages previously reported for the immunoperoxidase protocol. Both methods were tested on the same eel specimens and the immunofluorescence method showed a greater extent of relative DNA damage and a higher sensitivity. Although field validation is being carried out, our results indicate the utility of antibodies to rapidly detect DNA alterations in aquatic organisms, and to investigate the risk associated with genotoxins in marine environment.

  9. Trimerization of aromatic nitriles

    NASA Technical Reports Server (NTRS)

    Hsu, L. C. (Inventor)

    1977-01-01

    Triazine compounds and cross-linked polymer compositions were made by heating aromatic nitriles to a temperature in the range of about 100 C to about 700 C, in the presence of a catalyst or mixture of catalysts. Aromatic nitrile-modified (terminated and/or appended) imide, benzimidazole, imidazopyrrolone, quinoxaline, and other condensation type prepolymers or their precopolymers were made which were trimerized with or without a filler by the aforementioned catalytic trimerization process.

  10. 2-Amino-9H-pyrido[2,3-b]indole (AαC) Adducts and Thiol Oxidation of Serum Albumin as Potential Biomarkers of Tobacco Smoke.

    PubMed

    Pathak, Khyatiben V; Bellamri, Medjda; Wang, Yi; Langouët, Sophie; Turesky, Robert J

    2015-06-26

    2-Amino-9H-pyrido[2,3-b]indole (AαC) is a carcinogenic heterocyclic aromatic amine formed during the combustion of tobacco. AαC undergoes bioactivation to form electrophilic N-oxidized metabolites that react with DNA to form adducts, which can lead to mutations. Many genotoxicants and toxic electrophiles react with human serum albumin (albumin); however, the chemistry of reactivity of AαC with proteins has not been studied. The genotoxic metabolites, 2-hydroxyamino-9H-pyrido[2,3-b]indole (HONH-AαC), 2-nitroso-9H-pyrido[2,3-b]indole (NO-AαC), N-acetyloxy-2-amino-9H-pyrido[2,3-b]indole (N-acetoxy-AαC), and their [(13)C6]AαC-labeled homologues were reacted with albumin. Sites of adduction of AαC to albumin were identified by data-dependent scanning and targeted bottom-up proteomics approaches employing ion trap and Orbitrap MS. AαC-albumin adducts were formed at Cys(34), Tyr(140), and Tyr(150) residues when albumin was reacted with HONH-AαC or NO-AαC. Sulfenamide, sulfinamide, and sulfonamide adduct formation occurred at Cys(34) (AαC-Cys(34)). N-Acetoxy-AαC also formed an adduct at Tyr(332). Albumin-AαC adducts were characterized in human plasma treated with N-oxidized metabolites of AαC and human hepatocytes exposed to AαC. High levels of N-(deoxyguanosin-8-yl)-AαC (dG-C8-AαC) DNA adducts were formed in hepatocytes. The Cys(34) was the sole amino acid of albumin to form adducts with AαC. Albumin also served as an antioxidant and scavenged reactive oxygen species generated by metabolites of AαC in hepatocytes; there was a strong decrease in reduced Cys(34), whereas the levels of Cys(34) sulfinic acid (Cys-SO2H), Cys(34)-sulfonic acid (Cys-SO3H), and Met(329) sulfoxide were greatly increased. Cys(34) adduction products and Cys-SO2H, Cys-SO3H, and Met(329) sulfoxide may be potential biomarkers to assess exposure and oxidative stress associated with AαC and other arylamine toxicants present in tobacco smoke. © 2015 by The American Society for

  11. 2-Amino-9H-pyrido[2,3-b]indole (AαC) Adducts and Thiol Oxidation of Serum Albumin as Potential Biomarkers of Tobacco Smoke*

    PubMed Central

    Pathak, Khyatiben V.; Bellamri, Medjda; Wang, Yi; Langouët, Sophie; Turesky, Robert J.

    2015-01-01

    2-Amino-9H-pyrido[2,3-b]indole (AαC) is a carcinogenic heterocyclic aromatic amine formed during the combustion of tobacco. AαC undergoes bioactivation to form electrophilic N-oxidized metabolites that react with DNA to form adducts, which can lead to mutations. Many genotoxicants and toxic electrophiles react with human serum albumin (albumin); however, the chemistry of reactivity of AαC with proteins has not been studied. The genotoxic metabolites, 2-hydroxyamino-9H-pyrido[2,3-b]indole (HONH-AαC), 2-nitroso-9H-pyrido[2,3-b]indole (NO-AαC), N-acetyloxy-2-amino-9H-pyrido[2,3-b]indole (N-acetoxy-AαC), and their [13C6]AαC-labeled homologues were reacted with albumin. Sites of adduction of AαC to albumin were identified by data-dependent scanning and targeted bottom-up proteomics approaches employing ion trap and Orbitrap MS. AαC-albumin adducts were formed at Cys34, Tyr140, and Tyr150 residues when albumin was reacted with HONH-AαC or NO-AαC. Sulfenamide, sulfinamide, and sulfonamide adduct formation occurred at Cys34 (AαC-Cys34). N-Acetoxy-AαC also formed an adduct at Tyr332. Albumin-AαC adducts were characterized in human plasma treated with N-oxidized metabolites of AαC and human hepatocytes exposed to AαC. High levels of N-(deoxyguanosin-8-yl)-AαC (dG-C8-AαC) DNA adducts were formed in hepatocytes. The Cys34 was the sole amino acid of albumin to form adducts with AαC. Albumin also served as an antioxidant and scavenged reactive oxygen species generated by metabolites of AαC in hepatocytes; there was a strong decrease in reduced Cys34, whereas the levels of Cys34 sulfinic acid (Cys-SO2H), Cys34-sulfonic acid (Cys-SO3H), and Met329 sulfoxide were greatly increased. Cys34 adduction products and Cys-SO2H, Cys-SO3H, and Met329 sulfoxide may be potential biomarkers to assess exposure and oxidative stress associated with AαC and other arylamine toxicants present in tobacco smoke. PMID:25953894

  12. Aromatic Polyimide Foam

    NASA Technical Reports Server (NTRS)

    Weiser, Erik S. (Inventor); St.Clair, Terry L. (Inventor); Echigo, Yoshiaki (Inventor); Kaneshiro, Hisayasu (Inventor)

    2000-01-01

    A mechanically undensified aromatic polyimide foam is made from an aromatic polyimide precursor solid residuum and has the following combination of properties: a density according to ASTM D-3574A of about 0.5 pounds/cu.ft to about 20 pounds/cu.ft; a compression strength according to ASTM D-3574C of about 1.5 psi to about 1500 psi; and a limiting oxygen index according to ASTM D-2863 of about 35% oxygen to about 75% oxygen at atmospheric pressure. The aromatic polyimide foam has no appreciable solid inorganic contaminants which are residues of inorganic blowing agents. The aromatic polyimide which constitutes the aromatic polyimide foam has a glass transition temperature (Tg) by differential scanning calorimetry of about 235 C to about 400 C; and a thermal stability of 0 to about 1% weight loss at 204 C as determined by thermogravinietric analysis (TGA). The aromatic polyimide foam has utility as foam insulation and as structural foam, for example, for aeronautical, aerospace and maritime applications.

  13. Biocatalytic Reductions of Baylis - Hillman Adducts

    SciTech Connect

    A Walton; W Conerly; Y Pompeu; B Sullivan; J Stewart

    2011-12-31

    Baylis-Hillman adducts are highly useful synthetic intermediates; to enhance their value further, we sought enantiocomplementary alkene reductases to introduce chirality. Two solutions emerged: (1) a wild-type protein from Pichia stipitis (OYE 2.6), whose performance significantly outstrips that of the standard enzyme (Saccharomyces pastorianus OYE1), and (2) a series of OYE1 mutants at position 116 (Trp in the wild-type enzyme). To understand how mutations could lead to inverted enantioselectivity, we solved the X-ray crystal structure of the Trp116Ile OYE1 variant complexed with a cyclopentenone substrate. This revealed key protein-ligand interactions that control the orientation of substrate binding above the FMN cofactor.

  14. A novel chiral aliphatic-aromatic diamine promoted direct, highly enantio- and diastereoselective Michael addition of cyclohexanone to nitroolefins under solvent-free conditions.

    PubMed

    Miao, Shifeng; Bai, Jinjin; Yang, Jin; Zhang, Yawen

    2010-10-01

    A series of new highly efficient chiral aliphatic-aromatic diamine catalysts have been designed and successfully applied to the asymmetric Michael addition of cyclohexanone with nitroolefins under solvent-free conditions without any acidic additives. The desired adducts were obtained in high yields with excellent enantio- and diastereoselectivities of syn products (up to >99% ee, >99:1 dr).

  15. DNA adduct formation by alachlor metabolites

    SciTech Connect

    Brown, M.A.; Kimmel, E.C.; Casida, J.E.

    1988-01-01

    The extent of DNA adduct formation by alachlor (ArN(CH/sub 2/OCH/sub 3/)C(O)CH/sub 2/Cl wherein Ar is 2,6-diethylphenyl) and its metabolites is used as a guide to deduce the causal agent(s) in the carcinogenicity of this major herbicide. (/sup 14/C-phenyl)Alachlor is compared to its two metabolic cleavage products, (/sup 14/C-phenyl) 2-chloro-N-(2,6-diethylphenyl)acetamide (CDEPA) (ArNHC(O)CH/sub 2/Cl) and (/sup 14/C-phenyl)2,6-diethylaniline (DEA) (ArNH/sub 2/), and to (/sup 14/C-methoxy)alachlor in various in vitro and in vivo systems. Horseradish peroxidase and hydrogen peroxide activate DEA, but not CEDPA or alachlor, for formation of adducts with calf thymus DNA, which probably involves 2,6-diethylnitrosobenzene (ArNO) as an intermediate. Mouse liver microsomes and NADPH are both required to enhance the binding from each labeled preparation to calf thymus DNA; 4-fold higher labeling is observed from (/sup 14/C-methoxy)- than from (/sup 14/C-phenyl)alachlor. This 4-fold preferential DNA labeling from the /sup 14/C-methoxy compound is likewise found in the liver of mice treated intraperitoneally. Mouse liver protein and hemoglobin are also labeled, in vivo, with (/sup 14/C-phenyl)alachlor, -CDEPA and -DEA, and, as with the DNA, the labeling of these proteins is 1.5- to 2-fold higher with (/sup 14/C-methoxy)alachlor.

  16. Glottal Adduction and Subglottal Pressure in Singing.

    PubMed

    Herbst, Christian T; Hess, Markus; Müller, Frank; Švec, Jan G; Sundberg, Johan

    2015-07-01

    Previous research suggests that independent variation of vocal loudness and glottal configuration (type and degree of vocal fold adduction) does not occur in untrained speech production. This study investigated whether these factors can be varied independently in trained singing and how subglottal pressure is related to average glottal airflow, voice source properties, and sound level under these conditions. A classically trained baritone produced sustained phonations on the endoscopic vowel [i:] at pitch D4 (approximately 294 Hz), exclusively varying either (a) vocal register; (b) phonation type (from "breathy" to "pressed" via cartilaginous adduction); or (c) vocal loudness, while keeping the others constant. Phonation was documented by simultaneous recording of videokymographic, electroglottographic, airflow and voice source data, and by percutaneous measurement of relative subglottal pressure. Register shifts were clearly marked in the electroglottographic wavegram display. Compared with chest register, falsetto was produced with greater pulse amplitude of the glottal flow, H1-H2, mean airflow, and with lower maximum flow declination rate (MFDR), subglottal pressure, and sound pressure. Shifts of phonation type (breathy/flow/neutral/pressed) induced comparable systematic changes. Increase of vocal loudness resulted in increased subglottal pressure, average flow, sound pressure, MFDR, glottal flow pulse amplitude, and H1-H2. When changing either vocal register or phonation type, subglottal pressure and mean airflow showed an inverse relationship, that is, variation of glottal flow resistance. The direct relation between subglottal pressure and airflow when varying only vocal loudness demonstrated independent control of vocal loudness and glottal configuration. Achieving such independent control of phonatory control parameters would be an important target in vocal pedagogy and in voice therapy. Copyright © 2015 The Voice Foundation. Published by Elsevier Inc

  17. Radiation and chemical studies of carcinogens, polycyclic aromatic hydrocarbons

    SciTech Connect

    Chen, Chiachieh.

    1989-01-01

    Radiation and polycyclic aromatic hydrocarbons (PAH's) are environmental pollutants. 3MC effectively neutralized the lethality of C3H mouse 10T1/2 cells resulting from B(a)P or DMBA. PAH binding to macromolecules increased linearly with exposure, but DNA-adducts saturated with exposure. 3MC or {alpha}NF appreciably reduced the formation of DNA adducts due to B(a)P or DMBA. The reductions in DNA-adduct formation did not result from a reduction in the induction of AHH. By using DNA adducts as chemical dose, and plotting the DMBA survival curve as a function of DMBA-DNA adducts, the curve was an exponential curve. A similar application with B(a)P-DNA adduct showed the survival curve as a shoulder followed by an exponential region. When 10T1/2 cells were treated with X-radiation and a PAH, the nontoxic compounds and B(a)P did not show any significant effect on X-ray survival curve. However, the damage due to DMBA was found to be additive to X-ray damage. The latter property of DMBA was lost when cells were cotreated with 3MC and DMBA presumably because damage to DNA due to DMBA alone was suppressed. Thus, the combined action is complex. DMBA produced damage in 10T1/2 cells that added to radiation damage. Although a nontoxic PAH could neutralize the effect of a toxic PAH, the former were not able to mitigate the lethal effects of radiation. Operationally, the latter results suggested that a nontoxic PAH could cancel out the effect of a toxic one because it inhibited the formation of the DNA damage with which radiation damage could interact rather than because the nontoxic PAH removed the radiation damage with which the PAH could interact. It showed that at least 4 hours were required for DMBA to affect the sublethal radiation damage repair, a period long enough for a large fraction of the latter damage to have been lost.

  18. Prolonged Acetaminophen-Protein Adduct Elimination During Renal Failure, Lack of Adduct Removal by Hemodiafiltration, and Urinary Adduct Concentrations After Acetaminophen Overdose.

    PubMed

    Curry, Steven C; Padilla-Jones, Angela; O'Connor, Ayrn D; Ruha, Anne-Michelle; Bikin, Dale S; Wilkins, Diana G; Rollins, Douglas E; Slawson, Matthew H; Gerkin, Richard D

    2015-06-01

    Elevated concentrations of serum acetaminophen-protein adducts, measured as protein-derived acetaminophen-cysteine (APAP-CYS), have been used to support a diagnosis of APAP-induced liver injury when histories and APAP levels are unhelpful. Adducts have been reported to undergo first-order elimination, with a terminal half-life of about 1.6 days. We wondered whether renal failure would affect APAP-CYS elimination half-life and whether continuous venovenous hemodiafiltration (CVVHDF), commonly used in liver failure patients, would remove adducts to lower their serum concentrations. Terminal elimination half-lives of serum APAP-CYS were compared between subjects with and without renal failure in a prospective cohort study of 168 adults who had ingested excessive doses of APAP. APAP-CYS concentrations were measured in plasma ultrafiltrate during CVVHDF at times of elevated serum adduct concentrations. Paired samples of urine and serum APAP-CYS concentrations were examined to help understand the potential importance of urinary elimination of serum adducts. APAP-CYS elimination half-life was longer in 15 renal failure subjects than in 28 subjects with normal renal function (41.3 ± 2.2 h versus 26.8 ± 1.1 h [mean ± SEM], respectively, p < 0.001). CVVHDF failed to remove detectable amounts of APAP-CYS in any of the nine subjects studied. Sixty-eight percent of 557 urine samples from 168 subjects contained no detectable APAP-CYS, despite levels in serum up to 16.99 μM. Terminal elimination half-life of serum APAP-CYS was prolonged in patients with renal failure for reasons unrelated to renal urinary adduct elimination, and consideration of prolonged elimination needs to be considered if attempting back-extrapolation of adduct concentrations. CVVHDF did not remove detectable APAP-CYS, suggesting approximate APAP-protein adduct molecular weights ≥ 50,000 Da. The presence of urinary APAP-CYS in the minority of instances was most compatible with renal

  19. Derivatization of isothiocyanates and their reactive adducts for chromatographic analysis.

    PubMed

    Agerbirk, Niels; De Nicola, Gina Rosalinda; Olsen, Carl Erik; Müller, Caroline; Iori, Renato

    2015-10-01

    Isothiocyanates form adducts with a multitude of biomolecules, and these adducts need analytical methods. Likewise, analytical methods for hydrophilic isothiocyanates are needed. We considered reaction with ammonia to form thiourea derivatives. The hydrophilic, glycosylated isothiocyanate moringin, 4-(α-L-rhamnopyranosyloxy)benzyl isothiocyanate, was efficiently derivatized to the thiourea derivative by incubation with ammonia. The hydrophobic benzyl isothiocyanate was also efficiently derivatized to the thiourea derivative. The thiourea group provided a UV absorbing chromophore, and the derivatives showed expectable sodium and hydrogen adducts in ion trap mass spectrometry and were suitable for liquid chromatography analysis. Reactive dithiocarbamate adducts constitute the major type of reactive ITC adduct expected in biological matrices. Incubation of a model dithiocarbamate with ammonia likewise resulted in conversion to the corresponding thiourea derivative, suggesting that a variety of matrix-bound reactive isothiocyanate adducts can be determined using this strategy. As an example of the application of the method, recovery of moringin and benzyl isothiocyanate applied to cabbage leaf discs was studied in simulated insect feeding assays. The majority of moringin was recovered as native isothiocyanate, but a major part of benzyl isothiocyanate was converted to reactive adducts. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Quantitation of DNA adducts by stable isotope dilution mass spectrometry

    PubMed Central

    Tretyakova, Natalia; Goggin, Melissa; Janis, Gregory

    2012-01-01

    Exposure to endogenous and exogenous chemicals can lead to the formation of structurally modified DNA bases (DNA adducts). If not repaired, these nucleobase lesions can cause polymerase errors during DNA replication, leading to heritable mutations potentially contributing to the development of cancer. Due to their critical role in cancer initiation, DNA adducts represent mechanism-based biomarkers of carcinogen exposure, and their quantitation is particularly useful for cancer risk assessment. DNA adducts are also valuable in mechanistic studies linking tumorigenic effects of environmental and industrial carcinogens to specific electrophilic species generated from their metabolism. While multiple experimental methodologies have been developed for DNA adduct analysis in biological samples – including immunoassay, HPLC, and 32P-postlabeling – isotope dilution high performance liquid chromatography-electrospray ionization-tandem mass spectrometry (HPLC-ESI-MS/MS) generally has superior selectivity, sensitivity, accuracy, and reproducibility. As typical DNA adducts concentrations in biological samples are between 0.01 – 10 adducts per 108 normal nucleotides, ultrasensitive HPLC-ESI-MS/MS methodologies are required for their analysis. Recent developments in analytical separations and biological mass spectrometry – especially nanoflow HPLC, nanospray ionization MS, chip-MS, and high resolution MS – have pushed the limits of analytical HPLC-ESI-MS/MS methodologies for DNA adducts, allowing researchers to accurately measure their concentrations in biological samples from patients treated with DNA alkylating drugs and in populations exposed to carcinogens from urban air, drinking water, cooked food, alcohol, and cigarette smoke. PMID:22827593

  1. Immunodetection of Serum Albumin Adducts as Biomarkers for Organophosphorus Exposure

    PubMed Central

    Chen, Sigeng; Zhang, Jun; Lumley, Lucille

    2013-01-01

    A major challenge in organophosphate (OP) research has been the identification and utilization of reliable biomarkers for the rapid, sensitive, and efficient detection of OP exposure. Although Tyr 411 OP adducts to human serum albumin (HSA) have been suggested to be one of the most robust biomarkers in the detection of OP exposure, the analysis of HSA-OP adduct detection has been limited to techniques using mass spectrometry. Herein, we describe the procurement of two monoclonal antibodies (mAb-HSA-GD and mAb-HSA-VX) that recognized the HSA Tyr 411 adduct of soman (GD) or S-[2-(diisopropylamino)ethyl]-O-ethyl methylphosphonothioate (VX), respectively, but did not recognize nonphosphonylated HSA. We showed that mAb-HSA-GD was able to detect the HSA Tyr 411 OP adduct at a low level (i.e., human blood plasma treated with 180 nM GD) that could not be detected by mass spectrometry. mAb-HSA-GD and mAb-HSA-VX showed an extremely low-level detection of GD adducted to HSA (on the order of picograms). mAb-HSA-GD could also detect serum albumin OP adducts in blood plasma samples from different animals administered GD, including rats, guinea pigs, and monkeys. The ability of the two antibodies to selectively recognize nerve agents adducted to serum albumin suggests that these antibodies could be used to identify biomarkers of OP exposure and provide a new biologic approach to detect OP exposure in animals. PMID:23192655

  2. Analytical methods in DNA and protein adduct analysis.

    PubMed

    Koivisto, Pertti; Peltonen, Kimmo

    2010-11-01

    DNA or protein adducts are reaction products of endogenous or exogenous chemicals and cellular macromolecules. Adducts are useful in toxicological studies and/or human biomonitoring exercises. In particular, DNA damage provides invaluable information for risk analysis. Second, metabolites or conjugates can be regarded as markers of phase II reactions though they may not give accurate information about the levels of reactive and damage-provoking reactive compounds or intermediates. Electrophiles are often short-lived molecules and therefore difficult to monitor. In contrast, adducts are often chemically stable, though their levels in biological samples are low, which makes their detection challenging. The assay of adducts is similar to the analysis of any other trace organic molecule, i.e. problems with the matrix and small amounts of analytes in samples. The (32)P-postlabelling assay is a specific method for DNA adducts but immunochemical and fluorescence-based methods have been developed which can detect adducts linked to both DNA and protein. Tandem mass spectrometry, particularly if combined with ultrahigh-performance liquid chromatography, is currently the recommended detection technique; however investigators are striving to develop novel ways to achieve greater sensitivity. Standards are a prerequisite in adduct analysis, but unfortunately they are seldom commercially available.

  3. /sup 32/P-postlabeling assay for carcinogen-DNA adducts: nuclease P/sub 1/-mediated enhancement of its sensitivity and applications

    SciTech Connect

    Reddy, M.V.; Randerath, K.

    1987-12-01

    Exceedingly sensitive assays are required for the detection of DNA adducts formed in humans exposed to low levels of environmental genotoxicants and therapeutic drugs. A /sup 32/P-postlabeling procedure for detection and quantitation of aromatic carcinogen-DNA lesions with a sensitivity limit of 1 adduct in 10/sup 7/ to 10/sup 8/ nucleotides has been described previously. In the standard procedure, DNA is enzymatically digested to 3'-phosphorylated normal and adducted mononucleotides, which are /sup 32/P-labeled at their 5'-hydroxyl groups by T4 polynucleotide kinase-catalyzed (/sup 32/P) phosphate transfer from (..gamma..-/sup 32/P)ATP. /sup 32/P-labeled derivatives are resolved by TLC, detected by autoradiography, and quantitated by counting. This assay has been recently utilized for the determination and partial characterization of DNA adducts formed in somatic and reproductive tissues of rats given the clinically used anticancer drug, mitomycin C. The drug exhibits similar levels of covalent binding to DNA in most tissues. Further studies have revealed that adducted nucleotides are primarily guanine derivatives that are resistant to 3'-dephosphorylation by Penicillium citrinum nuclease P/sub 1/. The latter observation has been utilized to enhance the /sup 32/P-assay's sensitivity to 1 adduct in 10/sup 10/ nucleotides for a 10-..mu..g DNA sample by postincubation of DNA digests with nuclease P/sup 1/ before /sup 32/P-labeling. The new assay has also shown utility in the analysis of very low levels of age- and tissue-related DNA modifications, which might arise from dietary or endogenous compounds, in untreated rats and humans.

  4. DNA Adducts of the Tobacco Carcinogens 2-Amino-9H-pyrido[2,3-b]indole and 4-Aminobiphenyl are Formed at Environmental Exposure levels and Persist in Human Hepatocytes

    PubMed Central

    Nauwelaërs, Gwendoline; Bellamri, Medjda; Fessard, Valérie; Turesky, Robert J.; Langouët, Sophie

    2013-01-01

    Aromatic amines and structurally related heterocyclic aromatic amines (HAAs) are produced during the combustion of tobacco or during the high-temperature cooking of meat. Exposure to some of these chemicals may contribute to the etiology of several common types of human cancers. 2-Amino-9H-pyrido[2,3-b]indole (AαC) is the most abundant HAA formed in mainstream tobacco smoke: it arises in amounts that are 25–100 times greater than the levels of the arylamine, 4-aminobiphenyl (4-ABP), a human carcinogen. 2-Amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) is a prevalent HAA formed in cooked meats. AαC and MeIQx are rodent carcinogens; however, their carcinogenic potency in humans is unknown. A preliminary assessment of the carcinogenic potential of these HAAs in humans was conducted by examining the capacity of primary human hepatocytes to form DNA adducts of AαC and MeIQx, in comparison to 4-ABP, followed by the kinetics of DNA adduct removal by cellular enzyme repair systems. The principal DNA adducts formed were N-(deoxyguanosin-8-yl) (dG-C8) adducts. Comparable levels of DNA adducts were formed with AαC and 4-ABP, whereas adduct formation was ~5-fold lower for MeIQx. dG-C8-AαC and dG-C8-4-ABP were formed at comparable levels in a concentration-dependent manner in human hepatocytes treated with procarcinogens over a ten thousand-fold concentration range (1 nM – 10 µM). Pretreatment of hepatocytes with furafylline, a selective inhibitor of cytochrome P450 1A2, resulted in a strong diminution of DNA adducts signifying that P450 1A2 is a major P450 isoform involved in bioactivation of these procarcinogens. The kinetics of adduct removal varied for each hepatocyte donor. Approximately half of the DNA adducts were removed within 24 h of treatment; however, the remaining lesions persisted over 5 days. The high levels of AαC present in tobacco smoke and its propensity to form persistent DNA adducts in human hepatocytes, suggests that AαC can contribute to

  5. DNA adducts of the tobacco carcinogens 2-amino-9H-pyrido[2,3-b]indole and 4-aminobiphenyl are formed at environmental exposure levels and persist in human hepatocytes.

    PubMed

    Nauwelaërs, Gwendoline; Bellamri, Medjda; Fessard, Valérie; Turesky, Robert J; Langouët, Sophie

    2013-09-16

    Aromatic amines and structurally related heterocyclic aromatic amines (HAAs) are produced during the combustion of tobacco or during the high-temperature cooking of meat. Exposure to some of these chemicals may contribute to the etiology of several common types of human cancers. 2-Amino-9H-pyrido[2,3-b]indole (AαC) is the most abundant HAA formed in mainstream tobacco smoke: it arises in amounts that are 25-100 times greater than the levels of the arylamine, 4-aminobiphenyl (4-ABP), a human carcinogen. 2-Amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) is a prevalent HAA formed in cooked meats. AαC and MeIQx are rodent carcinogens; however, their carcinogenic potency in humans is unknown. A preliminary assessment of the carcinogenic potential of these HAAs in humans was conducted by examining the capacity of primary human hepatocytes to form DNA adducts of AαC and MeIQx, in comparison to 4-ABP, followed by the kinetics of DNA adduct removal by cellular enzyme repair systems. The principal DNA adducts formed were N-(deoxyguanosin-8-yl) (dG-C8) adducts. Comparable levels of DNA adducts were formed with AαC and 4-ABP, whereas adduct formation was ∼5-fold lower for MeIQx. dG-C8-AαC and dG-C8-4-ABP were formed at comparable levels in a concentration-dependent manner in human hepatocytes treated with procarcinogens over a 10,000-fold concentration range (1 nM-10 μM). Pretreatment of hepatocytes with furafylline, a selective inhibitor of cytochrome P450 1A2, resulted in a strong diminution of DNA adducts signifying that P450 1A2 is a major P450 isoform involved in bioactivation of these procarcinogens. The kinetics of adduct removal varied for each hepatocyte donor. Approximately half of the DNA adducts were removed within 24 h of treatment; however, the remaining lesions persisted over 5 days. The high levels of AαC present in tobacco smoke and its propensity to form persistent DNA adducts in human hepatocytes suggest that AαC can contribute to DNA damage

  6. Research on Aromatic Poly

    NASA Astrophysics Data System (ADS)

    Kiebooms, Rafael Hugo Ludo

    1995-11-01

    A detailed analysis of the literature indicated that substituents can only be used at the level of improving properties during processing, that end groups are only important for those polymers where the energy difference between the aromatic and quinoid structure is very small, and that stability of pi delocalisation is the most important tool for the design of low bandgap polymers. From our research it appeared that, based on a detailed NMR and FT-Raman analysis of oligomers and model compounds, the low band gap of PITN could be associated with the quinoid structure. However, a theoretical analysis of the UV-vis data of a series of aromatic isothianaphthene oligomers indicates that a substantial lowering of the band gap can be obtained in planar aromatic isothianaphthene systems. A parallel investigation of PTFITN, a soluble isothianaphthene analogue, gave some indications that this polymer should possess an aromatic structure. The aromatic structure makes it possible that the fluorines probably induce non planarity such that inter ring pi -conjugation is lowered to a considerable extent. This could explain the increased band gap of 2.1eV observed by Swann et al.^{[1] }. Analysis of a series of aza-analogues of PITN revealed that in these materials it should be possible to combine a planar aromatic geometry with enhanced processability. The 4,5-diaza and 4,7-diaza isothianaphthene polymers can therefore be considered as very promising low band gap materials. Finally, we showed that it is possible to combine the aromatic isothianaphthene ring system with another heterocycle such as thiophene in a formal copolymer. Through the development of a highly specific and efficient synthesis route to 1,3-dithienylisothianaphthene (DTI, 4), we established the basis for the further synthesis and study of formal copolymers with tailor-made electronic properties. ftn ^{[1]}M. J. Swann, G. Brooke, D. Bloor. Synth.Met., 55-57, 281-286, (1993).

  7. Molecular dosimetry of DNA damage induced by polycyclic aromatic hydrocarbons; relevance for exposure monitoring and risk assessment.

    PubMed

    Baan, R A; Steenwinkel, M J; van den Berg, P T; Roggeband, R; van Delft, J H

    1994-12-01

    Polycyclic aromatic hydrocarbons (PAH) form a large group of organic chemicals that are widely distributed in our environment as pollutants of air, water and soil. Several PAH are carcinogenic in rodents, while exposure to these compounds has been associated with various types of human cancer. Upon entering the body, PAH may be converted into reactive electrophilic species, which can give rise to the formation of DNA adducts. DNA adduct formation is considered to be the initial event in chemical carcinogenesis. In this paper, two methods are illustrated that are widely used to determine PAH-DNA adduct formation, namely 32P-postlabelling, and immunochemical analysis with specific antibodies. The applications of the 32P-postlabelling assay comprise the following: A study of interspecies differences in PAH bioactivation in vitro, with microsomal preparations isolated from liver tissue of various rodent species and of human origin; the results indicate that there are considerable qualitative differences between the adduct patterns obtained, which is relevant with respect to extrapolation from animal to man. The analysis of DNA adduct formation in fish retrieved from marine environments polluted to various extents with PAH; results of these studies show a correlation between liver-DNA adduct levels in these fish and the degree of PAH contamination in the aquatic environment. Biomonitoring of PAH exposure through analysis of adducts in blood cells obtained from heavy and light smokers; the data show a fair correlation between PAH-DNA adduct levels in white blood cells and cotinine content in blood plasma, the latter being used as a marker for exposure to cigarette smoke.(ABSTRACT TRUNCATED AT 250 WORDS)

  8. Seasonal variations in the levels of PAH–DNA adducts in young adults living in Mexico City

    PubMed Central

    García-Suástegui, W. A.; Huerta-Chagoya, A.; Carrasco-Colín, K. L.; Pratt, M. M.; John, K.; Petrosyan, P.; Rubio, J.; Poirier, M. C.; Gonsebatt, M. E.

    2011-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous components of polluted air. The Mexico City Metropolitan Area (MCMA), one of the most densely populated areas in the world, is 2240 m above sea level. At this altitude, less oxygen is available, making combustion less efficient and therefore producing more PAH pollutants. According to the Automatic Monitoring Network in Mexico City (RAMA, for its Spanish initials; http://www.sma.df.gob.mx/simat2/informaciontecnica/index.php?opcion=5&opciondifusion_bd=90), which performs environmental monitoring, the critical air pollutants in Mexico City are ozone and particulate matter (PM). PM emissions increase during the dry season (winter to spring) and decrease during the rainy season (summer to autumn). The bioactivation of some PAHs produces reactive metabolites that bind to DNA, and the presence of elevated levels of PAH–DNA adducts in tissues such as blood lymphocytes represents an elevated risk for the development of cancer. We have compared the levels of PAH–DNA adducts and the percentage of cells with chromosomal aberrations (CWAs) using a matched set of peripheral blood lymphocytes obtained on two separate occasions from young non-smoking inhabitants of the MCMA (n = 92) during the 2006 dry season and the following rainy season. PAH–DNA adducts were analysed using the r7, t8-dihydroxy-t-9, 10-oxy-7,8,9,10-tetrahydrobenzo[a]pyrene (BPDE)–DNA chemiluminescence immunoassay (CIA). The percentages of CWA were determined in cultured lymphocytes from the same individuals. Both DNA adduct levels and chromosomal aberrations were tested for correlation with lifestyle and the polymorphisms of cytochromes P450 CYP1A1 and CYP1B1 as well as glutathione-S-transferases GSTM1 and GSTT1. The levels of PAH–DNA adducts were significantly higher (P < 0.001) in the dry season (10.66 ± 3.05 per 109 nt, n = 92) than during the rainy season (9.50 ± 2.85 per 109 nt, n = 92) and correlated with the seasonal levels of particulate

  9. Increased levels of etheno-DNA adducts and genotoxicity biomarkers of long-term exposure to pure diesel engine exhaust.

    PubMed

    Shen, Meili; Bin, Ping; Li, Haibin; Zhang, Xiao; Sun, Xin; Duan, Huawei; Niu, Yong; Meng, Tao; Dai, Yufei; Gao, Weimin; Yu, Shanfa; Gu, Guizhen; Zheng, Yuxin

    2016-02-01

    Etheno-DNA adducts are biomarkers for assessing oxidative stress. In this study, the aim was to detect the level of etheno-DNA adducts and explore the relationship between the etheno-DNA adducts and genotoxicity biomarkers of the diesel engine exhaust (DEE)-exposed workers. We recruited 86 diesel engine testing workers with long-term exposure to DEE and 99 non-DEE-exposed workers. The urinary mono-hydroxylated polycyclic aromatic hydrocarbons (OH-PAHs) and etheno-DNA adducts (εdA and εdC) were detected by HPLC-MS/MS and UPLC-MS/MS, respectively. Genotoxicity biomarkers were also evaluated by comet assay and cytokinesis-block micronucleus assay. The results showed that urinary εdA was significantly higher in the DEE-exposed workers (p<0.001), exhibited 2.1-fold increase compared with the non-DEE-exposed workers. The levels of urinary OH-PAHs were positively correlated with the level of εdA among all the study subjects (p<0.001). Moreover, we found that the increasing level of εdA was significantly associated with the increased olive tail moment, percentage of tail DNA, or frequency of micronucleus in the study subjects (p<0.01). No significant association was observed between the εdC level and any measured genotoxicity biomarkers. In summary, εdA could serve as an indicator for DEE exposure in the human population. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. DNA bulky adducts in a Mediterranean population correlate with environmental ozone concentration, an indicator of photochemical smog.

    PubMed

    Palli, Domenico; Saieva, Calogero; Grechi, Daniele; Masala, Giovanna; Zanna, Ines; Barbaro, Antongiulio; Decarli, Adriano; Munnia, Armelle; Peluso, Marco

    2004-03-01

    Ozone (O(3)), the major oxidant component in photochemical smog, mostly derives from photolysis of nitrogen dioxide. O(3) may have biologic effects directly and/or via free radicals reacting with other primary pollutants and has been reported to influence daily mortality and to increase lung cancer risk. Although DNA damage may be caused by ozone itself, only other photochemical reaction products (as oxidised polycyclic aromatic hydrocarbons) may form bulky DNA adducts, a reliable biomarker of genotoxic damage and cancer risk, showing a seasonal trend. In a large series consisting of 320 residents in the metropolitan area of Florence, Italy, enrolled in a prospective study for the period 1993-1998 (206 randomly sampled volunteers, 114 traffic-exposed workers), we investigated the correlation between individual levels of DNA bulky adducts and a cumulative O(3) exposure score. The average O(3) concentrations were calculated for different time windows (0-5 to 0-90 days) prior to blood drawing for each participant, based on daily measurements provided by the local monitoring system. Significant correlations between DNA adduct levels and O3 cumulative exposure scores in the last 2-8 weeks before enrollment emerged in never smokers. Correlations were highest in the subgroup of never smokers residing in the urban area and not occupationally exposed to vehicle traffic pollution, with peak values for average concentrations 4-6 weeks before enrollment (r = 0.34). Our current findings indicate that DNA adduct formation may be modulated by individual characteristics and by the cumulative exposure to environmental levels of ozone in the last 4-6 weeks, possibly through ozone-associated reactive pollutants.

  11. A fluorescence-based analysis of aristolochic acid-derived DNA adducts.

    PubMed

    Romanov, Victor; Sidorenko, Victoria; Rosenquist, Thomas A; Whyard, Terry; Grollman, Arthur P

    2012-08-01

    Aristolochic acids (AAs), major components of plant extracts from Aristolochia species, form (after metabolic activation) pro-mutagenic DNA adducts in renal tissue. The DNA adducts can be used as biomarkers for studies of AA toxicity. Identification of these adducts is a complicated and time-consuming procedure. We present here a fast, nonisotopic, fluorescence-based assay for the detection of AA-DNA adducts in multiple samples. This approach allows analysis of AA adducts in synthetic DNA with known nucleotide composition and analysis of DNA adducts formed from chemically diverse AAs in vitro. The method can be applied to compare AA-DNA adduct formation in cells and tissues.

  12. The aromatic ene reaction

    NASA Astrophysics Data System (ADS)

    Niu, Dawen; Hoye, Thomas R.

    2014-01-01

    The ene reaction is a pericyclic process in which an alkene with an allylic hydrogen atom (the ene donor) reacts with a second unsaturated species (the enophile) to form a new product with a transposed π-bond. The aromatic ene reaction, in which the alkene component is embedded in an aromatic ring, has only been reported in a few (four) instances and has proceeded in low yield (≤6%). Here, we show efficient aromatic ene reactions in which a thermally generated aryne intermediate engages a pendant m-alkylarene substituent to produce a dearomatized isotoluene, itself another versatile but rare reactive intermediate. Our experiments were guided by computational studies that revealed structural features conducive to the aromatic ene process. We proceeded to identify a cascade comprising three reactions: (1) hexadehydro-Diels-Alder (for aryne generation), (2) intramolecular aromatic ene and (3) bimolecular Alder ene. The power of this cascade is evident from the structural complexity of the final products, the considerable scope, and the overall efficiency of these multistage, reagent- and by-product-free, single-pot transformations.

  13. The aromatic ene reaction

    PubMed Central

    Niu, Dawen; Hoye, Thomas R.

    2014-01-01

    The ene reaction is a pericyclic process in which an alkene having an allylic hydrogen atom (the ene donor) reacts with a second unsaturated species (the enophile) to form a new product with a transposed π-bond. The aromatic ene reaction, in which the alkene component is embedded in an aromatic ring, has only been reported in a few (four) instances and has proceeded in low yield (≤6%). Here we show efficient aromatic ene reactions in which a thermally generated aryne engages a pendant m-alkylarene substituent to produce a dearomatized isotoluene, itself another versatile but rare reactive intermediate. Our experiments were guided by computational studies that revealed structural features conducive to the aromatic ene process. We proceeded to identify a cascade comprising three reactions: (i) hexadehydro-Diels-Alder (for aryne generation), (ii) intramolecular aromatic ene, and (iii) bimolecular Alder ene. The power of this cascade is evident from the structural complexity of the final products, the considerable scope, and the overall efficiency of these multi-stage, reagent- and byproduct-free, single-pot transformations. PMID:24345944

  14. Sex differences in risk of lung cancer: Expression of genes in the PAH bioactivation pathway in relation to smoking and bulky DNA adducts.

    PubMed

    Mollerup, Steen; Berge, Gisle; Baera, Rita; Skaug, Vidar; Hewer, Alan; Phillips, David H; Stangeland, Lodve; Haugen, Aage

    2006-08-15

    It is controversial whether women have a higher lung cancer susceptibility compared to men. We previously reported higher levels of smoking-related bulky DNA adducts in female lungs. In a pilot study (27 cases), we also found a higher level of female lung cytochrome P4501A1 (CYP1A1) gene expression. In the present extended study we report on the pulmonary expression of several genes involved in polycyclic aromatic hydrocarbon bioactivation in relation to sex, smoking and DNA adducts. CYP1A1, CYP1B1, aryl hydrocarbon receptor and microsomal epoxide hydrolase gene expression was measured by quantitative real-time reverse transcriptase-PCR in 121 normal lung tissue samples. The expression of CYP1A1 and CYP1B1 was significantly higher among current smokers compared to ex-smokers and never-smokers. Among current smokers, females had a 3.9-fold higher median level of CYP1A1 compared to males (p = 0.011). CYP1B1 expression was not related to sex. Lung DNA adducts (measured by 32P-postlabeling) were highly significantly related to CYP1A1 (p < 0.0001) irrespective of smoking-status. Our results are consistent with the hypothesis that CYP1A1 plays a significant role in lung DNA adduct formation and support a higher susceptibility to lung cancer among females. Copyright 2006 Wiley-Liss, Inc

  15. Structure of adduct X, the last unknown of the six major DNA adducts of mitomycin C formed in EMT6 mouse mammary tumor cells.

    PubMed

    Palom, Y; Belcourt, M F; Musser, S M; Sartorelli, A C; Rockwell, S; Tomasz, M

    2000-06-01

    Treatment of EMT6 mouse mammary tumor cells with mitomycin C (MC) results in the formation of six major MC-DNA adducts. We identified the last unknown of these ("adduct X") as a guanine N(2) adduct of 2, 7-diaminomitosene (2,7-DAM), in which the mitosene is linked at its C-10 position to guanine N(2). The assigned structure is based on UV and mass spectra of adduct X isolated directly from the cells, as well as on its difference UV, second-derivative UV, and circular dichroism spectra, synthesis from [8-(3)H]deoxyguanosine, and observation of its heat stability. These tests were carried out using 17 microg of synthetic material altogether. The mechanism of formation of adduct X involves reductive metabolism of MC to 2,7-DAM, which undergoes a second round of reductive activation to alkylate DNA, yielding adduct X and another 2,7-DAM-guanine adduct (adduct Y), which is linked at guanine N7 to the mitosene. Adduct Y has been described previously. Adduct X is formed preferentially at GpC, while adduct Y favors the GpG sequence. In contrast to MC-DNA adducts, the 2,7-DAM-DNA adducts are not cytotoxic.

  16. Biological activities of eco-friendly synthesized Hantzsch adducts.

    PubMed

    Pacheco, Samira R; Braga, Taniris C; da Silva, Daniel L; Horta, Livia P; Reis, Fabiano S; Ruiz, Ana Lucia T G; de Carvalho, Joao E; Modolo, Luzia V; de Fatima, Ângelo

    2013-09-01

    Fourteen Hantzsch adducts with different substituents at the C-4 position were synthesized through multicomponent reactions by using citric or lactic acid as catalysts. To the best of our knowledge, this is the first report on the synthesis of such a class of compounds based on multicomponent reactions catalyzed by non-toxic organic acids. The potential to scavenge reactive nitrogen/oxygen species (RNS/ROS) and the ability to inhibit cancer cell growth were then investigated. Among the synthesized compounds, adduct 15 was the most promising free radical scavenger, while adduct 20 was shown to have a wider spectrum of action on the cancer cells studied. These results highlight Hantzsch adducts as lead compounds for obtaining new free radical scavengers and anticancer agents.

  17. Paclitaxel Enhances Carboplatin-DNA Adduct Formation and Cytotoxicity

    SciTech Connect

    Jiang, Shuai; Pan, Amy W.; Lin, Tzu-yin; Zhang, Hongyong; Malfatti, Michael; Turteltaub, Kenneth; Henderson, Paul T.; Pan, Chong-xian

    2015-11-06

    This rapid report focuses on the pharmacodynamic mechanism of the carboplatin/paclitaxel combination and correlates it with its cytotoxicity. Consistent with the synergistic to additive antitumor activity (the combination index ranging from 0.53 to 0.94), cells exposed to this combination had significantly increased carboplatin-DNA adduct formation when compared to that of carboplatin alone (450 ± 30 versus 320 ± 120 adducts per 108 nucleotides at 2 h, p = 0.004). Removal of paclitaxel increased the repair of carboplatin-DNA adducts: 39.4 versus 33.1 adducts per 108 nucleotides per hour in carboplatin alone (p = 0.021). In conclusion, this rapid report provides the first pharmacodynamics data to support the use of carboplatin/paclitaxel combination in the clinic.

  18. Mass spectrometric analysis of tobacco-specific hemoglobin adducts.

    PubMed Central

    Schäffler, G; Betz, C; Richter, E

    1993-01-01

    Hemoglobin adducts of the common metabolite of the tobacco-specific nitrosamine (TSNA) 4-hydroxy-1-(3-pyridyl)-1-butanone (HPB) and of 4-aminobiphenyl (4-ABP) were quantified in blood samples from smokers and nonsmokers to test their suitability for biomonitoring tobacco smoke exposure. Additionally, TSNA adducts were measured in nasal snuff users. Mild alkaline treatment of hemoglobin releases 4-ABP and HPB, which were analyzed in parallel by capillary gas chromatography with electronic impact or negative ion chemical-ionization mass spectrometry (EI- or NICI-GC-MS). Samples of snuff users showed high levels of HPB adducts not correlated with the amount or type of snuff used. HPB concentrations in smokers and nonsmokers, however, were much lower, with no group-specific differences detectable. In contrast, 4-ABP adduct levels were much higher in smokers than in nonsmokers, confirming the significant difference between these two groups reported by others. PMID:8319620

  19. Paclitaxel Enhances Carboplatin-DNA Adduct Formation and Cytotoxicity

    PubMed Central

    Jiang, Shuai; Pan, Amy W.; Lin, Tzu-yin; Zhang, Hongyong; Malfatti, Michael; Turteltaub, Kenneth; Henderson, Paul T.; Pan, Chong-xian

    2016-01-01

    This rapid report focuses on the pharmacodynamic mechanism of the carboplatin/paclitaxel combination and correlates it with its cytotoxicity. Consistent with the synergistic to additive antitumor activity (the combination index ranging from 0.53 to 0.94), cells exposed to this combination had significantly increased carboplatin-DNA adduct formation when compared to that of carboplatin alone (450 ± 30 versus 320 ± 120 adducts per 108 nucleotides at 2 h, p = 0.004). Removal of paclitaxel increased the repair of carboplatin-DNA adducts: 39.4 versus 33.1 adducts per 108 nucleotides per hour in carboplatin alone (p = 0.021). This rapid report provides the first pharmacodynamics data to support the use of carboplatin/paclitaxel combination in the clinic. PMID:26544157

  20. Paclitaxel Enhances Carboplatin-DNA Adduct Formation and Cytotoxicity

    DOE PAGES

    Jiang, Shuai; Pan, Amy W.; Lin, Tzu-yin; ...

    2015-11-06

    This rapid report focuses on the pharmacodynamic mechanism of the carboplatin/paclitaxel combination and correlates it with its cytotoxicity. Consistent with the synergistic to additive antitumor activity (the combination index ranging from 0.53 to 0.94), cells exposed to this combination had significantly increased carboplatin-DNA adduct formation when compared to that of carboplatin alone (450 ± 30 versus 320 ± 120 adducts per 108 nucleotides at 2 h, p = 0.004). Removal of paclitaxel increased the repair of carboplatin-DNA adducts: 39.4 versus 33.1 adducts per 108 nucleotides per hour in carboplatin alone (p = 0.021). In conclusion, this rapid report provides themore » first pharmacodynamics data to support the use of carboplatin/paclitaxel combination in the clinic.« less

  1. Condensed tannin-resorcinol adducts in laminating adhesives

    Treesearch

    Richard W. Hemingway; Roland E. Kreibich

    1985-01-01

    A condensed tannin-resorcinol adduct made by co-reaction of an extract from southern pine bark with resorcinol at a 2 to 1 weight ratio was used to prepare a laminating resin in which the entire amount of resorcinol normally used was replaced by this adduct. The resin was formulated into a room temperature setting adhesive that meets the basic criteria of product...

  2. Arytenoid adduction combined with Gore-Tex medialization thyroplasty.

    PubMed

    McCulloch, T M; Hoffman, H T; Andrews, B T; Karnell, M P

    2000-08-01

    To describe the technique of combined Gore-Tex medialization thyroplasty with arytenoid adduction and to determine the long-term vocal outcome of patients treated for unilateral vocal cord paralysis with this procedure. A retrospective chart review and patient reevaluation for patients treated at The University of Iowa Hospitals and Clinics between May 1995 and June 1999. The review addressed patient demographics, perioperative and long-term complications, and voice outcomes. Details of the surgical technique are provided within the manuscript. Seventy-two Gore-Tex medialization procedures were completed. Arytenoid adduction was included in 22 of these procedures. This subset of patients was compared with the patients treated with Gore-Tex alone. No major postoperative complications occurred in either group. Preoperative and postoperative voice and videostroboscopy data were available for 19 arytenoid adduction patients and 25 Gore-Tex alone patients. On a seven-point scale (6 [severely abnormal] --> 0 [normal voice]), the average patient rating of voice dysfunction improved from 4.2 to 1.6 (arytenoid adduction) and 4.5 to 2.8 (Gore-Tex alone). Maximum phonation time improved from 6.9 seconds to 16.7 seconds in the arytenoid adduction group. Subjective voice assessment employing the four-point GRBAS scale (3 [severely abnormal] --> 0 [normal]) identified average improvement from an overall grade of 2.1 to 0.8 arytenoid adduction and 2.2 to 1.5 in the Gore-Tex alone group. Improvement was identified in the vocal quality of breathiness from 1.9 to 0.2 (arytenoid adduction) and 1.9 to 0.9 (Gore-Tex alone). The combined technique of Gore-Tex medialization thyroplasty and arytenoid adduction provide functional results that appear to exceed the improvement attained with medialization alone.

  3. [Hemoglobin adducts as biomarkers of human exposure to selected xenobiotics].

    PubMed

    Bukowska, Bożena

    2015-06-12

    In the living and working environments more and more new substances of anthropogenic origin exerting toxic properties appear. Simultaneously, the evaluation of human exposure is assessed. For many years adducts of hemoglobin (Hb) have been useful markers of the exposure of humans to various xenobiotics. These adducts are also termed biologically effective dose biomarkers. This paper focuses on a review of literature, mainly from the years 2010-2014, which refers to the hemoglobin adducts of toxic compounds with electrophilic properties. In the interactions of xenobiotics with hemoglobin, groups such as thiol, amino, carboxyl and hydroxyl of this hemoprotein are involved. These combinations occur most often in the reaction of xenobiotics with an N-terminal amino group of valine in Hb, imidazole nitrogen of histidine and cysteine sulfhydryl β93. Hb adducts are characterized by high availability, a long period of occurrence (up to 120 days) in the circulatory system, and high durability, and they have contact with all cells of the body. The measurement of hemoglobin adducts can be potentially used in the assessment of exposure to many xenobiotics such as acrylamide; substances present in tobacco smoke, e.g. benzo(α)pyrene and benzanthracene, ethylene oxide, aryl amines; and substances used on a large scale in industry such as glycidol and naphthalene and its derivatives. Recently the possibility of determination of hemoglobin adducts with estrogen metabolites has been postulated as indicators informing about heightened risk of breast cancer. Protein adducts are used as an alternative to DNA adducts for different classes of electrophilic substances.

  4. Superconductivity in aromatic hydrocarbons

    NASA Astrophysics Data System (ADS)

    Kubozono, Yoshihiro; Goto, Hidenori; Jabuchi, Taihei; Yokoya, Takayoshi; Kambe, Takashi; Sakai, Yusuke; Izumi, Masanari; Zheng, Lu; Hamao, Shino; Nguyen, Huyen L. T.; Sakata, Masafumi; Kagayama, Tomoko; Shimizu, Katsuya

    2015-07-01

    'Aromatic hydrocarbon' implies an organic molecule that satisfies the (4n + 2) π-electron rule and consists of benzene rings. Doping solid aromatic hydrocarbons with metals provides the superconductivity. The first discovery of such superconductivity was made for K-doped picene (Kxpicene, five benzene rings). Its superconducting transition temperatures (Tc's) were 7 and 18 K. Recently, we found a new superconducting Kxpicene phase with a Tc as high as 14 K, so we now know that Kxpicene possesses multiple superconducting phases. Besides Kxpicene, we discovered new superconductors such as Rbxpicene and Caxpicene. A most serious problem is that the shielding fraction is ⩽15% for Kxpicene and Rbxpicene, and it is often ∼1% for other superconductors. Such low shielding fractions have made it difficult to determine the crystal structures of superconducting phases. Nevertheless, many research groups have expended a great deal of effort to make high quality hydrocarbon superconductors in the five years since the discovery of hydrocarbon superconductivity. At the present stage, superconductivity is observed in certain metal-doped aromatic hydrocarbons (picene, phenanthrene and dibenzopentacene), but the shielding fraction remains stubbornly low. The highest priority research area is to prepare aromatic superconductors with a high superconducting volume-fraction. Despite these difficulties, aromatic superconductivity is still a core research target and presents interesting and potentially breakthrough challenges, such as the positive pressure dependence of Tc that is clearly observed in some phases of aromatic hydrocarbon superconductors, suggesting behavior not explained by the standard BCS picture of superconductivity. In this article, we describe the present status of this research field, and discuss its future prospects.

  5. Adduction of untested derived stimulus relations depends on environmental complexity.

    PubMed

    Rippy, Sterling M; Doughty, Adam H

    2017-10-01

    The present research assessed adduction involving derived stimulus relations as a function of environmental complexity. In Group CA, four college students were trained with arbitrary-matching-to-sample discriminations that could have established four, 3-member stimulus classes. In Group EA, four other students were trained with discriminations that could have established four, 5-member classes. Neither group received derived-relations testing; instead, adduction was assessed immediately after the baseline discriminations were learned. The adduction assessment required participants to derive the untested CA (Group CA) or EA (Group EA) equivalence relations and combine them with their already learned math skills. All participants in Group CA showed above 90% accuracy during the adduction assessment, whereas only one of four Group EA participants responded in that manner. These results extend adduction to untested equivalence relations and clarify the environmental conditions under which such adduction is less likely to occur (i.e., with larger relational networks). Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Detection of adriamycin-DNA adducts by accelerator mass spectrometry.

    PubMed

    Coldwell, Kate; Cutts, Suzanne M; Ognibene, Ted J; Henderson, Paul T; Phillips, Don R

    2010-01-01

    There have been many attempts in the past to determine whether significant levels of Adriamycin-DNA adducts form in cells and contribute to the anticancer activity of this agent. Supraclincal drug levels have been required to study drug-DNA adducts because of the lack of sensitivity associated with many of the techniques employed, including liquid scintillation counting of radiolabeled drug. The use of accelerator mass spectrometry (AMS) has provided the first direct evidence of Adriamycin-DNA adduct formation in cells at clinically relevant Adriamycin concentrations. The exceedingly sensitive nature of AMS has enabled over three orders of magnitude increased sensitivity of Adriamycin-DNA adduct detection (compared to liquid scintillation counting) and has revealed adduct formation within an hour of drug treatment. The rigorous protocol required for this approach, together with many notes on the precautions and procedures required in order to ensure that absolute levels of Adriamycin-DNA adducts can be determined with good reproducibility, is outlined in this chapter.

  7. Mapping Serum Albumin Adducts of the Food-borne Carcinogen 2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine by Data-Dependent Tandem Mass Spectrometry

    PubMed Central

    Peng, Lijuan; Dasari, Surendra; Tabb, David L.; Turesky, Robert J.

    2012-01-01

    2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) is a heterocyclic aromatic amine that is formed during the cooking of meats. PhIP is a potential human carcinogen: it undergoes metabolic activation to form electrophilic metabolites that bind to DNA and proteins, including serum albumin (SA). The structures of PhIP-SA adducts formed in vivo are unknown and require elucidation before PhIP protein adducts can be implemented as biomarkers in human studies. We previously examined the reaction of genotoxic N-oxidized metabolites of PhIP with human SA in vitro and identified covalent adducts formed at cysteine34 (Cys34); however, other adduction products were thought to occur. We have now identified adducts of PhIP formed at multiple sites of SA reacted with isotopic mixtures of electrophilic metabolites of PhIP and 2-amino-1-methyl-6-[2H5]-phenylimidazo[4,5-b]pyridine ([2H5]-PhIP). The metabolites used for study were: 2-nitro-1-methyl-6-phenylimidazo[4,5-b]pyridine (NO2-PhIP), 2-hydroxyamino-1-methyl-6-phenylimidazo[4,5-b]pyridine (HONH-PhIP), or N-acetyloxy-2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (N-acetoxy-PhIP). Following proteolytic digestion, PhIP-adducted peptides were separated by ultra performance liquid chromatography and characterized by ion trap mass spectrometry, employing isotopic data-dependent scanning. Analysis of the tryptic or tryptic/chymotryptic digests of SA modified with NO2-PhIP revealed that adduction occurred at Cys34, Lys195, Lys199, Lys351, Lys541, Tyr138, Tyr150, Tyr401, and Tyr411, whereas the only site of HONH-PhIP adduction was detected at Cys34. N-Acetoxy-PhIP, a penultimate metabolite of PhIP that reacts with DNA to form covalent adducts, did not appear to form stable adducts with SA; instead, PhIP and 2-amino-1-methyl-6-(5-hydroxy)-phenylimidazo[4,5-b]pyridine, an aqueous reaction product of the proposed nitrenium ion of PhIP, were recovered during the proteolysis of N-acetoxy-PhIP-modified SA. Some of these SA adduction

  8. Formation of DNA adducts in the skin of psoriasis patients, in human skin in organ culture, and in mouse skin and lung following topical application of coal-tar and juniper tar.

    PubMed

    Schoket, B; Horkay, I; Kósa, A; Páldeák, L; Hewer, A; Grover, P L; Phillips, D H

    1990-02-01

    Preparations of coal-tar and juniper tar (cade oil) that are used in the treatment of psoriasis are known to contain numerous potentially carcinogenic polycyclic aromatic hydrocarbons (PAH). Evidence of covalent binding to DNA by components of these mixtures was sought in a) human skin biopsy samples from 12 psoriasis patients receiving therapy with these agents, b) human skin explants maintained in organ culture and treated topically with the tars, and c) the skin and lungs of mice treated with repeated doses of the formulations following the regimen used in the clinic. DNA was isolated from the human and mouse tissues and digested enzymically to mononucleotides. 32P-Post-labeling analysis revealed the presence of aromatic DNA adducts in the biopsy samples at levels of up to 0.4 fmol total adducts/microgram DNA. Treatment of human skin in organ culture produced similar levels of adducts, while treatment with dithranol, a non-mutagenic therapeutic agent, resulted in chromatograms indistinguishable from those from untreated controls. In mouse skin, coal-tar ointment and juniper tar gave similar DNA adduct levels, with a similar time-course of removal: maximum levels (0.5 fmol/microgram DNA) at 24 h after the final treatment declined rapidly to 0.05 fmol/microgram at 7 d, thereafter declining slowly over the succeeding 25 d. However, while coal-tar ointment produced only very low levels of adducts in mouse lung (less than 0.03 fmol/microgram DNA), juniper tar produced adducts at a high level (0.7 fmol/microgram DNA) that were persistent in this tissue. These results provide direct evidence for the formation of potentially carcinogenic DNA damage in human and mouse tissue by components of these therapeutic tar preparations.

  9. Structural and Dynamic Characterization of Polymerase κ’s Minor Groove Lesion Processing Reveals How Adduct Topology Impacts Fidelity

    PubMed Central

    2015-01-01

    DNA lesion bypass polymerases process different lesions with varying fidelities, but the structural, dynamic, and mechanistic origins of this phenomenon remain poorly understood. Human DNA polymerase κ (Polκ), a member of the Y family of lesion bypass polymerases, is specialized to bypass bulky DNA minor groove lesions in a predominantly error-free manner, by housing them in its unique gap. We have investigated the role of the unique Polκ gap and N-clasp structural features in the fidelity of minor groove lesion processing with extensive molecular modeling and molecular dynamics simulations to pinpoint their functioning in lesion bypass. Here we consider the N2-dG covalent adduct derived from the carcinogenic aromatic amine, 2-acetylaminofluorene (dG-N2-AAF), that is produced via the combustion of kerosene and diesel fuel. Our simulations reveal how the spacious gap directionally accommodates the lesion aromatic ring system as it transits through the stages of incorporation of the predominant correct partner dCTP opposite the damaged guanine, with preservation of local active site organization for nucleotidyl transfer. Furthermore, flexibility in Polκ’s N-clasp facilitates the significant misincorporation of dTTP opposite dG-N2-AAF via wobble pairing. Notably, we show that N-clasp flexibility depends on lesion topology, being markedly reduced in the case of the benzo[a]pyrene-derived major adduct to N2-dG, whose bypass by Polκ is nearly error-free. Thus, our studies reveal how Polκ’s unique structural and dynamic properties can regulate its bypass fidelity of polycyclic aromatic lesions and how the fidelity is impacted by lesion structures. PMID:25148552

  10. Effects of Dietary Fish Oil on the Depletion of Carcinogenic PAH-DNA Adduct Levels in the Liver of B6C3F1 Mouse

    PubMed Central

    Zhou, Guo-Dong; Zhu, Huiping; Phillips, Tracie D.; Wang, Jianbo; Wang, Shi-Zhou; Wang, Fen; Amendt, Brad A.; Couroucli, Xanthi I.; Moorthy, Bhagavatula

    2011-01-01

    Many carcinogenic polycyclic aromatic hydrocarbons (PAHs) and their metabolites can bind covalently to DNA. Carcinogen-DNA adducts may lead to mutations in critical genes, eventually leading to cancer. In this study we report that fish oil (FO) blocks the formation of DNA adducts by detoxification of PAHs. B6C3F1 male mice were fed a FO or corn oil (CO) diet for 30 days. The animals were then treated with seven carcinogenic PAHs including benzo(a)pyrene (BaP) with one of two doses via a single intraperitoneal injection. Animals were terminated at 1, 3, or 7 d after treatment. The levels of DNA adducts were analyzed by the 32P-postlabeling assay. Our results showed that the levels of total hepatic DNA adducts were significantly decreased in FO groups compared to CO groups with an exception of low PAH dose at 3 d (P = 0.067). Total adduct levels in the high dose PAH groups were 41.36±6.48 (Mean±SEM) and 78.72±8.03 in 109 nucleotides (P = 0.011), respectively, for the FO and CO groups at 7 d. Animals treated with the low dose (2.5 fold lower) PAHs displayed similar trends. Total adduct levels were 12.21±2.33 in the FO group and 24.07±1.99 in the CO group, P = 0.008. BPDE-dG adduct values at 7 d after treatment of high dose PAHs were 32.34±1.94 (CO group) and 21.82±3.37 (FO group) in 109 nucleotides with P value being 0.035. Low dose groups showed similar trends for BPDE-dG adduct in the two diet groups. FO significantly enhanced gene expression of Cyp1a1 in both the high and low dose PAH groups. Gstt1 at low dose of PAHs showed high levels in FO compared to CO groups with P values being 0.014. Histological observations indicated that FO played a hepatoprotective role during the early stages. Our results suggest that FO has a potential to be developed as a cancer chemopreventive agent. PMID:22066002

  11. Effects of dietary fish oil on the depletion of carcinogenic PAH-DNA adduct levels in the liver of B6C3F1 mouse.

    PubMed

    Zhou, Guo-Dong; Zhu, Huiping; Phillips, Tracie D; Wang, Jianbo; Wang, Shi-Zhou; Wang, Fen; Amendt, Brad A; Couroucli, Xanthi I; Donnelly, Kirby C; Moorthy, Bhagavatula

    2011-01-01

    Many carcinogenic polycyclic aromatic hydrocarbons (PAHs) and their metabolites can bind covalently to DNA. Carcinogen-DNA adducts may lead to mutations in critical genes, eventually leading to cancer. In this study we report that fish oil (FO) blocks the formation of DNA adducts by detoxification of PAHs. B6C3F1 male mice were fed a FO or corn oil (CO) diet for 30 days. The animals were then treated with seven carcinogenic PAHs including benzo(a)pyrene (BaP) with one of two doses via a single intraperitoneal injection. Animals were terminated at 1, 3, or 7 d after treatment. The levels of DNA adducts were analyzed by the (32)P-postlabeling assay. Our results showed that the levels of total hepatic DNA adducts were significantly decreased in FO groups compared to CO groups with an exception of low PAH dose at 3 d (P = 0.067). Total adduct levels in the high dose PAH groups were 41.36±6.48 (Mean±SEM) and 78.72±8.03 in 10(9) nucleotides (P = 0.011), respectively, for the FO and CO groups at 7 d. Animals treated with the low dose (2.5 fold lower) PAHs displayed similar trends. Total adduct levels were 12.21±2.33 in the FO group and 24.07±1.99 in the CO group, P = 0.008. BPDE-dG adduct values at 7 d after treatment of high dose PAHs were 32.34±1.94 (CO group) and 21.82±3.37 (FO group) in 10(9) nucleotides with P value being 0.035. Low dose groups showed similar trends for BPDE-dG adduct in the two diet groups. FO significantly enhanced gene expression of Cyp1a1 in both the high and low dose PAH groups. Gstt1 at low dose of PAHs showed high levels in FO compared to CO groups with P values being 0.014. Histological observations indicated that FO played a hepatoprotective role during the early stages. Our results suggest that FO has a potential to be developed as a cancer chemopreventive agent.

  12. Polybenzimidazole via aromatic nucleophilic displacement

    NASA Technical Reports Server (NTRS)

    Connell, John W. (Inventor); Hergenrother, Paul M. (Inventor); Smith, Joseph G. (Inventor)

    1994-01-01

    Di(hydroxyphenyl)benzimidazole monomers were prepared from phenyl-4-hydroxybenzoate and aromatic bis(o-diamine)s. These monomers were used in the synthesis of soluble polybenzimidazoles. The reaction involved the aromatic nucleophilic displacement of various di(hydroxyphenyl)benzimidazole monomers with activated aromatic dihalides or activated aromatic dinitro compounds in the presence of an alkali metal base. These polymers exhibited lower glass transition temperatures, improved solubility, and better compression moldability over their commercial counterparts.

  13. Quantification of Hemoglobin and White Blood Cell DNA Adducts of the Tobacco Carcinogens 2-Amino-9H-pyrido[2,3-b]indole and 4-Aminobiphenyl Formed in Humans by Nanoflow Liquid Chromatography/Ion Trap Multistage Mass Spectrometry.

    PubMed

    Cai, Tingting; Bellamri, Medjda; Ming, Xun; Koh, Woon-Puay; Yu, Mimi C; Turesky, Robert J

    2017-06-19

    Aromatic amines covalently bound to hemoglobin (Hb) as sulfinamide adducts at the cysteine 93 residue of the Hb β chain have served as biomarkers to assess exposure to this class of human carcinogens for the past 30 years. In this study, we report that 2-amino-9H-pyrido[2,3-b]indole (AαC), an abundant carcinogenic heterocyclic aromatic amine formed in tobacco smoke and charred cooked meats, also reacts with Hb to form a sulfinamide adduct. A novel nanoflow liquid chromatography/ion trap multistage mass spectrometry (nanoLC-IT/MS(3)) method was established to assess exposure to AαC and the tobacco-associated bladder carcinogen 4-aminobiphenyl (4-ABP) through their Hb sulfinamide adducts. Following mild acid hydrolysis of Hb in vitro, the liberated AαC and 4-ABP were derivatized with acetic anhydride to form the N-acetylated amines, which were measured by nanoLC-IT/MS(3). The limits of quantification (LOQ) for AαC- and 4-ABP-Hb sulfinamide adducts were ≤7.1 pg/g Hb. In a pilot study, the mean level of Hb sulfinamide adducts of AαC and 4-ABP were, respectively, 3.4-fold and 4.8-fold higher in smokers (>20 cigarettes/day) than nonsmokers. In contrast, the major DNA adducts of 4-ABP, N-(2'-deoxyguanosin-8-yl)-4-aminobiphenyl, and AαC, N-(2'-deoxyguanosin-8-yl)-2-amino-9H-pyrido[2,3-b]indole, were below the LOQ (3 adducts per 10(9) bases) in white blood cell (WBC) DNA of smokers and nonsmokers. These findings reaffirm that tobacco smoke is a major source of exposure to AαC. Hb sulfinamide adducts are suitable biomarkers to biomonitor 4-ABP and AαC; however, neither carcinogen binds to DNA in WBC, even in heavy smokers, at levels sufficient for biomonitoring.

  14. A mitomycin-N6-deoxyadenosine adduct isolated from DNA.

    PubMed

    Palom, Y; Lipman, R; Musser, S M; Tomasz, M

    1998-03-01

    A minor N6-deoxyadenosine adduct of mitomycin C (MC) was isolated from synthetic oligonucleotides and calf thymus DNA, representing the first adduct of MC and a DNA base other than guanine. The structure of the adduct (8) was elucidated using submilligram quantities of total available material. UV difference spectroscopy, circular dichroism, and electrospray mass spectroscopy as well as chemical transformations were utilized in deriving the structure of 8. A series of synthetic oligonucleotides was designed to probe the specificities of the alkylation of adenine by MC. The nature and frequency of the oligonucleotide-MC adducts formed under conditions of reductive activation of MC were determined by their enzymatic digestion to the nucleoside level followed by quantitative analysis of the products by HPLC. The analyses indicated the following: (i) (A)n sequence is favored over (AT)n for adduct formation; (ii) the alkylation favors the duplex structure; (iii) at adenine sites only monofunctional alkylation occurs; (iv) the adenine-to-alkylation frequency in the model oligonucleotides was 0.3-0.6 relative to guanine alkylation at the 5'-ApG sequence but only 0.02-0.1 relative to guanine alkylation at 5'-CpG. The 5'-phosphodiester linkage of the MC-adenine adduct is resistant to snake venom diesterase. The overall ratio of adenine to guanine alkylation in calf thymus DNA was 0.03, indicating that 8 is a minor MC-DNA adduct relative to MC-DNA adducts at guanine residues in the present experimental residues in the present experimental system. However, the HPLC elution time of 8 coincides with that of a major, unknown MC adduct detected previously in mouse mammary tumor cells treated with radiolabeled MC [Bizanek, R., Chowdary, D., Arai, H., Kasai, M., Hughes, C. S., Sartorelli, A. C., Rockwell, S., and Tomasz, M. (1993) Cancer Res. 53, 5127-5134]. Thus, 8 may be identical or closely related to this major adduct formed in vivo. This possibility can now be tested by

  15. Synthetic access to poly-substituted 6-alkoxyindoles from 1,3-cyclohexanediones and nitroolefins through facile aromatization reaction.

    PubMed

    Ma, Li-Jian; Li, Xiao-Xia; Kusuyama, Tomoyo; El-Sayed, Ibrahim El-Tantawy; Inokuchi, Tsutomu

    2009-12-04

    6-Alkoxy-3-arylindoles were efficiently prepared from 1,3-cyclohexanedione enol ethers and beta-nitrostyrenes. Michael addition using the kinetically generated enolate, followed by Zn reduction of a nitro group of the resulting adducts produced the nitrones which were then treated with acetic anhydride to induce aromatization by dehydration and N-acetylation, which furnished the desired indoles by the DDQ oxidation. This methodology provides an easy entry toward various poly-substituted 6-alkoxyindoles.

  16. Partitioning of knee joint internal forces in gait is dictated by the knee adduction angle and not by the knee adduction moment.

    PubMed

    Adouni, M; Shirazi-Adl, A

    2014-05-07

    Medial knee osteoarthritis is a debilitating disease. Surgical and conservative interventions are performed to manage its progression via reduction of load on the medial compartment or equivalently its surrogate measure, the external adduction moment. However, some studies have questioned a correlation between the medial load and adduction moment. Using a musculoskeletal model of the lower extremity driven by kinematics-kinetics of asymptomatic subjects at gait midstance, we aim here to quantify the relative effects of changes in the knee adduction angle versus changes in the adduction moment on the joint response and medial/lateral load partitioning. The reference adduction rotation of 1.6° is altered by ±1.5° to 3.1° and 0.1° or the knee reference adduction moment of 17Nm is varied by ±50% to 25.5Nm and 8.5Nm. Quadriceps, hamstrings and tibiofemoral contact forces substantially increased as adduction angle dropped and diminished as it increased. The medial/lateral ratio of contact forces slightly altered by changes in the adduction moment but a larger adduction rotation hugely increased this ratio from 8.8 to a 90 while in contrast a smaller adduction rotation yielded a more uniform distribution. If the aim in an intervention is to diminish the medial contact force and medial/lateral load ratio, a drop of 1.5° in adduction angle is much more effective (causing respectively 12% and 80% decreases) than a reduction of 50% in the adduction moment (causing respectively 4% and 13% decreases). Substantial role of changes in adduction angle is due to the associated alterations in joint nonlinear passive resistance. These findings explain the poor correlation between knee adduction moment and tibiofemoral compartment loading during gait suggesting that the internal load partitioning is dictated by the joint adduction angle. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Genetic polymorphisms in biotransformation enzymes for benzo[a]pyrene and related levels of benzo[a]pyrene-7,8-diol-9,10-epoxide-DNA adducts in Goeckerman therapy.

    PubMed

    Beranek, Martin; Fiala, Zdenek; Kremlacek, Jan; Andrys, Ctirad; Hamakova, Kvetoslava; Chmelarova, Marcela; Palicka, Vladimir; Borska, Lenka

    2016-07-25

    Goeckerman therapy (GT) for psoriasis combines the therapeutic effect of crude coal tar (CCT) and ultraviolet radiation (UVR). CCT contains polycyclic aromatic hydrocarbons, some of which can form DNA adducts that may induce mutations and contribute to carcinogenesis. The aim of our work was to evaluate the relationship between concentrations of benzo[a]pyrene-7,8-diol-9,10-epoxide-DNA adducts (BPDE-DNA adducts) and rs4646903 (CYP1A1 gene), rs1048943 (CYP1A1), rs1056836 (CYP1B1), rs1051740 (EPHX1), rs2234922 (EPHX1) and rs8175347 (UGT1A1) polymorphic sites, and GSTM1 null polymorphism in 46 patients with chronic stable plaque psoriasis who underwent GT. The level of BPDE-DNA adducts was determined using the OxiSelect BPDE-DNA Adduct ELISA Kit. Polymerase chain reaction (PCR) and restriction fragment length polymorphism analysis (rs4646903, rs1048943, rs1051740, and rs2234922), fragment analysis (rs8175347), real-time PCR (rs1056836), and digital droplet PCR polymorphism (GSTM1) were used. CYP1B1*1/*1 wild-type subjects and CYP1B1*3/*1 heterozygotes for rs1056836 formed significantly higher amounts of BPDE-DNA adducts than CYP1B1*3/*3 homozygotes (p=0.031 and p=0.005, respectively). Regarding rs1051740, individuals with EPHX1*3/*1 heterozygosity revealed fewer adducts than EPHX1*1/*1 wild-type subjects (p=0.026). Our data suggest that CYP1B1/EPHX1 genotyping could help to predict the risk of DNA damage and to optimize doses of coal tar and UVR exposure in psoriatic patients in whom GT was applied.

  18. Identification of the major lesion from the reaction of an acridine-targeted aniline mustard with DNA as an adenine N1 adduct.

    PubMed

    Boritzki, T J; Palmer, B D; Coddington, J M; Denny, W A

    1994-01-01

    DNA adducts of two acridine-linked aniline half-mustards have been isolated and identified. The compound where the half-mustard is attached to the DNA-targeting acridine moiety by a short linker chain alkylates both double- and single-stranded DNA exclusively at guanine N7, as do the majority of known aromatic and aliphatic nitrogen mustards. The longer-chain analogue, also containing a more reactive half-mustard, shows a strikingly different pattern, alkylating double-stranded DNA to yield primarily (> 90%) the adenine N1 adduct, together with < 10% of the adenine N3 adduct and only trace amounts of the guanine N7 adduct. In the presence of MgCl2 (which is known not to inhibit the interaction of drugs at minor groove sites), the adenine N3 adduct is the major product. The latter compound is the first known aniline mustard (and apparently the first known alkylating agent of any type) to preferentially alkylate adenine at the N1 position in duplex DNA. These results are consistent with previous work [Prakash et al. (1990) Biochemistry 29, 9799-9807], which showed that the preferred site of DNA alkylation by the corresponding long-chain acridine-linked aniline bis-mustards in general was at major groove sites of adenines and identifies the major site of alkylation as adenine N1 and not N7. This selectivity for adenine N1 alkylation is suggested to result from a preference for the acridine mustard side chain of these compounds to project into the major groove following intercalation of the acridine, coupled with structural distortion of the DNA helix to make the N1 positions of adenines adjacent to the intercalation sites more accessible.

  19. Genetic variations of CYP2B6 gene were associated with plasma BPDE-Alb adducts and DNA damage levels in coke oven workers.

    PubMed

    Huang, Guoxiang; Guo, Huan; Wu, Tangchun

    2012-06-20

    Polycyclic aromatic hydrocarbons (PAHs), the main components of coke oven emissions, can induce activation of cytochrome P450 (CYP) enzymes, which metabolize PAHs and result in DNA damage by forming adducts. This study was designed to know whether genetic variants of CYP genes are associated with plasma benzo[a]pyrene-7,8-diol-9,10-epoxide-albumin (BPDE-Alb) adducts and DNA damage in coke oven workers. In this study, 298 workers were divided into four groups according to the environmental PAHs exposure levels. The concentrations of plasma BPDE-Alb adducts were detected by reverse-phase high-performance liquid chromatography and the DNA damage levels were measured using comet assay. Twelve tag single nucleotide polymorphisms (tagSNPs) of 4 CYP genes were selected and genotyped by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. In the top group, workers with CYP2B6 rs3760657GA genotype have lower BPDE-Alb adducts and DNA damage levels than those with rs3760657GG genotype (P<0.05). In the control group, the DNA damage levels of subjects with CYP1A1 rs4646421AA or GA+AA genotypes were lower than those with GG genotype (P<0.05). However, no such effects were shown for the other tagSNPs. These results suggested that genetic variations of CYP2B6 might be associated with low BPDE-Alb adducts and DNA damage levels in worker with high exposure to PAHs.

  20. Measurement of chromosomal aberrations, sister chromatid exchange, hprt mutations, and DNA adducts in peripheral lymphocytes of human populations at increased risk for cancer

    PubMed Central

    Jacobson-Kram, David; Albertini, Richard J.; Branda, Richard F.; Falta, Michael T.; Iype, P. Thomas; Kolodner, Ken; Liou, Saou-Hsing; McDiarmid, Melissa A.; Morris, Marcia; Nicklas, Janice A.; O'Neill, J. Patrick; Poirier, Miriam C.; Putman, Donald; Strickland, Paul T.; Williams, Jerry R.; Xiao, Shuqin

    1993-01-01

    Using a multidisciplinary approach, we have measured various indicators of DNA damage in peripheral lymphocytes of human populations potentially at increased risk for cancer. Sister chromatid exchanges (SCE) and polycyclic aromatic hydrocarbon (PAH)–DNA adducts were evaluated in a group of firefighters; chromosomal aberrations and hprt mutations were evaluated in a group of cancer patients undergoing radioimmunoglobulin therapy (RIT); SCE and acrolein-modified DNA were measured in cancer chemotherapy patients and in pharmacists preparing chemotherapy prescriptions; and SCE and PAH–DNA adducts are being measured in U.S. army troops stationed in Kuwait. Our results indicate that both SCE and PAH–DNA adduct levels were not elevated in firefighters, but that other factors such as smoking status and race were risk factors for increased SCE and PAH–DNA adducts. RIT was found to increase background rates of chromosome-type aberrations and frequencies of hprt mutations and there was a strong correlation between levels of therapy-induced chromosome damage sustained in vivo and in vitro sensitivity to radiation-induced chromosome damage. Peripheral blood lymphocytes of cancer patients treated with cyclophosphamide showed higher levels of SCE and had a higher incidence of acrolein adducts in DNA. Lymphocytes from pharmacists preparing antineoplastic drugs were found to acquire increased in vitro sensitivity to SCE induction by phosphoramide mustard with increased lifetime duration of drug handling. A prospective, longitudinal study was performed to identify environmental factors that modulate genetic damage in breast cancer patients. Women with benign breast masses and no apparent disease served as controls. Mutant frequency, cloning efficiency, and chromosomal aberration frequency did not differ significantly among the three groups. The results described and the data being gathered on troops stationed in Kuwait suggest that all the methodologies described can be

  1. Integrated reforming/aromatization process

    SciTech Connect

    Harandi, M.N.; Owen, H.

    1990-06-26

    This patent describes an integrated process for increasing the gasoline yield from a catalytic reforming process. It comprises: charging a naphtha boiling range feedstream to a catalytic reforming reaction zone under reforming conversion conditions; withdrawing a reactor effluent stream from the reforming reaction zone; separating the reactor effluent stream into a hydrogen-rich gas stream and an unstabilized reformate stream; further separating the unstabilized reformate in a fractionator into an overhead stream containing C{sub 4} - components and a bottom stream containing C{sub 6} + components; charging the fractionator overhead stream to a catalytic aromatization zone under aromatization conversion conditions; withdrawing an aromatization zone effluent stream from the aromatization zone; cooling the aromatization zone effluent stream; separating the cooled aromatization zone effluent steam into a C{sub 4} - stream and a C{sub 5} + stream; and refluxing the C{sub 5} + aromatic gasoline stream to the fractionation zone.

  2. Impact of genetic modulation of SULT1A enzymes on DNA adduct formation by aristolochic acids and 3-nitrobenzanthrone.

    PubMed

    Arlt, Volker M; Meinl, Walter; Florian, Simone; Nagy, Eszter; Barta, Frantisek; Thomann, Marlies; Mrizova, Iveta; Krais, Annette M; Liu, Maggie; Richards, Meirion; Mirza, Amin; Kopka, Klaus; Phillips, David H; Glatt, Hansruedi; Stiborova, Marie; Schmeiser, Heinz H

    2017-04-01

    Exposure to aristolochic acid (AA) causes aristolochic acid nephropathy (AAN) and Balkan endemic nephropathy (BEN). Conflicting results have been found for the role of human sulfotransferase 1A1 (SULT1A1) contributing to the metabolic activation of aristolochic acid I (AAI) in vitro. We evaluated the role of human SULT1A1 in AA bioactivation in vivo after treatment of transgenic mice carrying a functional human SULT1A1-SULT1A2 gene cluster (i.e. hSULT1A1/2 mice) and Sult1a1(-/-) mice with AAI and aristolochic acid II (AAII). Both compounds formed characteristic DNA adducts in the intact mouse and in cytosolic incubations in vitro. However, we did not find differences in AAI-/AAII-DNA adduct levels between hSULT1A1/2 and wild-type (WT) mice in all tissues analysed including kidney and liver despite strong enhancement of sulfotransferase activity in both kidney and liver of hSULT1A1/2 mice relative to WT, kidney and liver being major organs involved in AA metabolism. In contrast, DNA adduct formation was strongly increased in hSULT1A1/2 mice compared to WT after treatment with 3-nitrobenzanthrone (3-NBA), another carcinogenic aromatic nitro compound where human SULT1A1/2 is known to contribute to genotoxicity. We found no differences in AAI-/AAII-DNA adduct formation in Sult1a1(-/-) and WT mice in vivo. Using renal and hepatic cytosolic fractions of hSULT1A1/2, Sult1a1(-/-) and WT mice, we investigated AAI-DNA adduct formation in vitro but failed to find a contribution of human SULT1A1/2 or murine Sult1a1 to AAI bioactivation. Our results indicate that sulfo-conjugation catalysed by human SULT1A1 does not play a role in the activation pathways of AAI and AAII in vivo, but is important in 3-NBA bioactivation.

  3. Synthesis, characterization, and solvolysis of mono- and bis-S-(glutathionyl) adducts of methylene-bis-(phenylisocyanate) (MDI).

    PubMed

    Reisser, Martin; Schmidt, Brigitte F; Brown, William E

    2002-10-01

    Bifunctional isocyanates are highly reactive compounds that undergo nucleophilic attack by a variety of functional groups available in the biological system. While the etiology of the respiratory disease caused by diisocyanates is not fully understood, a great deal of research has been performed to elucidate the chemical mechanisms involved in the direct and indirect effects of these compounds. Since adducts of isocyanates are found not only to proteins along the entire respiratory tree but also to proteins in the circulatory system, it is likely that a transport mechanism for the isocyanate from the respiratory to the circulatory system exists. The initial reaction of isocyanates with cellular thiols to form thiocarbamates, which are known to release the isocyanate under physiological conditions, is believed to provide a possible carrier mechanism for the isocyanate functional group. Previous work with aliphatic mono-isocyanates and the aromatic diisocyanate toluene diisocyanate has demonstrated the feasibility of this mechanism. Adding to this database, the products of the reaction of the highly water-insoluble, low vapor pressure, methylene-bis-(phenylisocyanate) (MDI) with glutathione were synthesized, and their chemical stability under various pH and buffer conditions was tested. Novel synthetic routes were developed for both the mono- and bis-S-(glutathionyl) adducts with MDI that yielded each compound in analytically pure form. Both compounds were found to be unstable under mild basic conditions (phosphate-buffered saline, pH 7.4, and NaHCO(3), pH 8.2), however to a different degree. Furthermore, a significant influence of the pH value (the rate of degradation increases with pH) and the concentration of free glutathione (increasing thiol stabilizes the adduct) on the stability was observed, indicating a base-catalyzed mechanism of the degradation/formation of the thiocarbamate bond. Unlike the monoadduct, which forms almost exclusively the polyurea upon

  4. Organocatalytic removal of formaldehyde adducts from RNA and DNA bases

    NASA Astrophysics Data System (ADS)

    Karmakar, Saswata; Harcourt, Emily M.; Hewings, David S.; Lovejoy, Alexander F.; Kurtz, David M.; Ehrenschwender, Thomas; Barandun, Luzi J.; Roost, Caroline; Alizadeh, Ash A.; Kool, Eric T.

    2015-09-01

    Formaldehyde is universally used to fix tissue specimens, where it forms hemiaminal and aminal adducts with biomolecules, hindering the ability to retrieve molecular information. Common methods for removing these adducts involve extended heating, which can cause extensive degradation of nucleic acids, particularly RNA. Here, we show that water-soluble bifunctional catalysts (anthranilates and phosphanilates) speed the reversal of formaldehyde adducts of mononucleotides over standard buffers. Studies with formaldehyde-treated RNA oligonucleotides show that the catalysts enhance adduct removal, restoring unmodified RNA at 37 °C even when extensively modified, while avoiding the high temperatures that promote RNA degradation. Experiments with formalin-fixed, paraffin-embedded cell samples show that the catalysis is compatible with common RNA extraction protocols, with detectable RNA yields increased by 1.5-2.4-fold using a catalyst under optimized conditions and by 7-25-fold compared with a commercial kit. Such catalytic strategies show promise for general use in reversing formaldehyde adducts in clinical specimens.

  5. Characterization of deoxyguanosine adducts from hydroquinone/benzoquinone

    SciTech Connect

    Jowa, J.; Winkel, S.; Witz, G.; Snyder, R.

    1986-03-01

    Occupational exposure to benzene has long been associated with the development of pancytopenia and leukemia. This toxicity has been attributed to the action of benzene metabolites. The authors have chosen to investigate the reaction of hydroquinone (HQ)/benzoquinone(BQ) with deoxyguanosine(dG) and DNA. (/sup 14/C)HQ was incubated with (/sup 3/H)dG in potassium phosphate buffer pH7.2 for 24 hours. Two dual labeled products were found by HPLC and presumed to be adducts. The same result was obtained when BQ was substituted in the reaction for HQ. Both adducts were found in isolated DNA from Clostridium perfringens, Micrococcus lysodeikticus, human placenta and calf thymus reacted with HO under similar conditions. One of the dG adducts was proposed to be (/sup 3/'OH) benzetheno(1,N-2)deoxyguanosine based on NMR and mass spectral results. The other adduct was characterized by a molecular weight of 339. The latter adduct was found in greater amounts than the former when HQ was reacted with denatured DNA.

  6. Organocatalytic Removal of Formaldehyde Adducts from RNA and DNA Bases

    PubMed Central

    Karmakar, Saswata; Harcourt, Emily M.; Hewings, David S.; Lovejoy, Alexander F.; Kurtz, David M.; Ehrenschwender, Thomas; Barandun, Luzi J.; Roost, Caroline; Alizadeh, Ash A.; Kool, Eric T.

    2015-01-01

    Formaldehyde is universally employed to fix tissue specimens, where it forms hemiaminal and aminal adducts with biomolecules, hindering the ability to retrieve molecular information. Common methods for removing these adducts involve extended heating, which can cause extensive degradation of nucleic acids, particularly RNA. Here we show that water-soluble bifunctional catalysts (anthranilates and phosphanilates) speed the reversal of formaldehyde adducts of mononucleotides over standard buffers. Studies with formaldehyde-treated RNA oligonucleotides show that the catalysts enhance adduct removal, restoring unmodified RNA at 37 °C even when extensively modified, and avoiding high temperatures that promote RNA degradation. Experiments with formalin-fixed, paraffin-embedded cell samples show that the catalysis is compatible with common RNA extraction protocols, with detectable RNA yields increased by 1.5–2.4 fold using a catalyst under optimized conditions, and by 7–25 fold compared to a commercial kit. Such catalytic strategies show promise for general use in reversing formaldehyde adducts in clinical specimens. PMID:26291948

  7. Organocatalytic removal of formaldehyde adducts from RNA and DNA bases.

    PubMed

    Karmakar, Saswata; Harcourt, Emily M; Hewings, David S; Scherer, Florian; Lovejoy, Alexander F; Kurtz, David M; Ehrenschwender, Thomas; Barandun, Luzi J; Roost, Caroline; Alizadeh, Ash A; Kool, Eric T

    2015-09-01

    Formaldehyde is universally used to fix tissue specimens, where it forms hemiaminal and aminal adducts with biomolecules, hindering the ability to retrieve molecular information. Common methods for removing these adducts involve extended heating, which can cause extensive degradation of nucleic acids, particularly RNA. Here, we show that water-soluble bifunctional catalysts (anthranilates and phosphanilates) speed the reversal of formaldehyde adducts of mononucleotides over standard buffers. Studies with formaldehyde-treated RNA oligonucleotides show that the catalysts enhance adduct removal, restoring unmodified RNA at 37 °C even when extensively modified, while avoiding the high temperatures that promote RNA degradation. Experiments with formalin-fixed, paraffin-embedded cell samples show that the catalysis is compatible with common RNA extraction protocols, with detectable RNA yields increased by 1.5-2.4-fold using a catalyst under optimized conditions and by 7-25-fold compared with a commercial kit. Such catalytic strategies show promise for general use in reversing formaldehyde adducts in clinical specimens.

  8. Glutathione Adduct Patterns of Michael-Acceptor Carbonyls.

    PubMed

    Slawik, Christian; Rickmeyer, Christiane; Brehm, Martin; Böhme, Alexander; Schüürmann, Gerrit

    2017-02-22

    Glutathione (GSH) has so far been considered to facilitate detoxification of soft organic electrophiles through covalent binding at its cysteine (Cys) thiol group, followed by stepwise catalyzed degradation and eventual elimination along the mercapturic acid pathway. Here we show that in contrast to expectation from HSAB theory, Michael-acceptor ketones, aldehydes and esters may form also single, double and triple adducts with GSH involving β-carbon attack at the much harder N-terminus of the γ-glutamyl (Glu) unit of GSH. In particular, formation of the GSH-N single adduct contradicts the traditional view that S alkylation always forms the initial reaction of GSH with Michael-acceptor carbonyls. To this end, chemoassay analyses of the adduct formation of GSH with nine α,β-unsaturated carbonyls employing high performance liquid chromatography and tandem mass spectrometry have been performed. Besides enriching the GSH adductome and potential biomarker applications, electrophilic N-terminus functio-nalization is likely to impair GSH homeostasis substantially through blocking the γ-glutamyl transferase catalysis of the first breakdown step of modified GSH, and thus its timely reconstitution. The discussion includes a comparison with cyclic adducts of GSH and furan metabolites as reported in literature, and quantum chemically calculated thermodynamics of hard-hard, hard-soft and soft-soft adducts.

  9. Antitumor Trans Platinum Adducts of GMP and AMP

    PubMed Central

    Liu, Yangzhong; Sivo, Maria F.; Natile, Giovanni

    2000-01-01

    Recently it has been shown that several analogues of the clinically ineffective trans-DDP exhibit antitumor activity comparable to that of cis-DDP. The present paper describes the binding of antitumor trans-[PtCl2(E-iminoether)2] (trans-EE) to guanosinemonophosphate (GMP) and adenosinemonophosphate (AMP). We have used HPLC and 1H and 15N NMR to characterize the different adducts. In the case of a 1:1 mixture of trans-EE and GMP, at an early stage of the reaction, a monofunctional adduct is formed which, subsequently, is partly converted into a monosolvated monofunctional species. After about 70 hours an equilibrium is established between chloro and solvato monofunctional adducts at a ratio of 30/70. In the presence of excess GMP (4:1) the initially formed monofunctional adducts react further to give two bifunctional adducts, one with the iminoether ligands in their original E configurations and the other with the iminoether ligands having one E and the other, Z configurations. The coordination geometry obtained by energy minimization calculations is in qualitative agreement with 2D NMR data. PMID:18475942

  10. PROTEIN ADDUCTS AS BIOMAKERS OF EXPOSURE TO ORGANOPHOSPHORUS COMPOUNDS

    PubMed Central

    Marsillach, Judit; Costa, Lucio G.; Furlong, Clement E.

    2013-01-01

    Exposure to organophosphorus (OP) compounds can lead to serious neurological damage or death. Following bioactivation by the liver cytochromes P450, the OP metabolites produced are potent inhibitors of serine active-site enzymes including esterases, proteases and lipases. OPs may form adducts on other cellular proteins. Blood cholinesterases (ChEs) have long served as biomarkers of OP exposure in humans. However, the enzymatic assays used for biomonitoring OP exposures have several drawbacks. A more useful approach will focus on multiple biomarkers and avoid problems with the enzymatic activity assays. OP inhibitory effects result from a covalent bond with the active-site serine of the target enzymes. The serine OP adducts become irreversible following a process referred to as aging where one alkyl group dissociates over variable lengths of time depending on the OP adduct. The OP-adducted enzyme then remains in circulation until it is degraded, allowing for a longer window of detection compared with direct analysis of OPs or their metabolites. Mass spectrometry (MS) provides a very sensitive method for identification of post-translational protein modifications. MS analyses of the percentage adduction of the active-site serine of biomarker proteins such as ChEs will eliminate the need for basal activity levels of the individual and will provide for a more accurate determination of OP exposure. MS analysis of biomarker proteins also provides information about the OP that has caused inhibition. Other useful biomarker proteins include other serine hydrolases, albumin, tubulin and transferrin. PMID:23261756

  11. Mass Spectrometric Characterization of Human Serum Albumin Adducts Formed with N-Oxidized Metabolites of 2-Amino-1-methyl-phenylimidazo[4,5-b]pyridine in Human Plasma and Hepatocytes

    PubMed Central

    Wang, Yi; Peng, Lijuan; Bellamri, Medjda; Langoueët, Sophie; Turesky, Robert J.

    2015-01-01

    2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), a carcinogenic heterocyclic aromatic amine formed in cooked meats, is metabolically activated to electrophilic intermediates that form covalent adducts with DNA and protein. We previously identified an adduct of PhIP formed at the Cys34 residue of human serum albumin following reaction of albumin with the genotoxic metabolite 2-hydroxyamino-1-methyl-6-phenylimidazo[4,5-b]pyridine (HONH-PhIP). The major adducted peptide recovered from a tryptic/chymotryptic digest was identified as the missed-cleavage peptide LQQC*[SO2PhIP]PFEDHVK, a [Cysteine-S-yl-PhIP]-S-dioxide linked adduct. In this investigation, we have characterized the albumin adduction products of N-sulfooxy-2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (N-sulfooxy-PhIP), which is thought to be a major genotoxic metabolite of PhIP formed in vivo. Targeted and data-dependent scanning methods showed that N-sulfooxy-PhIP adducted to the Cys34 of albumin in human plasma to form LQQC*[SO2PhIP]PFEDHVK at levels that were 8 to 10-fold greater than the adduct levels formed with N-(acetyloxy)-2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (N-acetoxy-PhIP) or HONH-PhIP. We also discovered that N-sulfooxy-PhIP forms an adduct at the sole tryptophan (Trp214) residue of albumin in the sequence AW*[PhIP]AVAR. However, stable adducts of PhIP with albumin were not detected in human hepatocytes. Instead, PhIP and 2-amino-1-methyl-6-(5-hydroxy)-phenylimidazo[4,5-b]pyridine (5-HO-PhIP), a solvolysis product of the proposed nitrenium ion of PhIP, were recovered during the proteolysis, suggesting a labile sulfenamide linkage had formed between an N-oxidized intermediate of PhIP and Cys34 of albumin. A stable adduct was formed at the Tyr411 residue of albumin in hepatocytes, and identified as a deaminated product of PhIP, Y*[desaminoPhIP]TK, where the 4-HO-tyrosine group bound to the C-2 imidazole atom of PhIP. PMID:25815793

  12. An acellular assay to assess the genotoxicity of complex mixtures of organic pollutants bound on size segregated aerosol. Part I: DNA adducts.

    PubMed

    Topinka, Jan; Hovorka, Jan; Milcova, Alena; Schmuczerova, Jana; Krouzek, Jiri; Rossner, Pavel; Sram, Radim J

    2010-10-20

    An acellular assay consisting of calf thymus DNA with/without rat liver microsomal S9 fraction was used to study the genotoxicity of complex mixtures of organic air pollutants bound to size segregated aerosols by means of DNA adduct analysis. We compared the genotoxicity of the organic extracts (EOMs) from three size fractions of aerosol ranging from 0.17μm to 10μm that were collected by high volume cascade impactors in four localities of the Czech Republic differing in the extent of the environmental pollution: (1) small village in proximity of a strip mine, (2) highway, (3) city center of Prague and (4) background station. The total DNA adduct levels induced by 100μg/ml of EOMs were analyzed by (32)P-postlabelling analysis with a nuclease P1 method for adduct enrichment. The main finding of the study was most of the observed genotoxicity was connected with a fine particulate matter fraction (<1μm). The concentrations of carcinogenic polycyclic aromatic hydrocarbons (c-PAHs) in EOMs indicate that fine fractions (0.5-1μm) bound the highest amount of c-PAHs in all aerosol sampling sites, which might be related to the higher specific surface of this fraction as compared with a course fraction (1-10μm) and higher mass as compared with a condensational fraction (0.17-0.5μm). As for aerosol mass, both fine and condensational fractions are effective carriers of c-PAHs. Similarly, the DNA adduct levels per m(3) of air were highest for the fine fraction, while the condensational fraction (strip mine site and city center) revealed the highest DNA adduct levels in cases where aerosol mass is taken into consideration. A strong correlation was found between the c-PAHs and DNA adduct levels induced by EOMs in all the localities and for various size fractions (R(2)=0.98, p<0.001). It may be concluded that the analysis of total DNA adducts induced in an acellular assay with/without metabolic activation represents a relatively simple method to assess the genotoxic potential

  13. DNA adducts: mass spectrometry methods and future prospects.

    PubMed

    Farmer, P B; Brown, K; Tompkins, E; Emms, V L; Jones, D J L; Singh, R; Phillips, D H

    2005-09-01

    Detection of DNA adducts is widely used for the monitoring of exposure to genotoxic carcinogens. Knowledge of the nature and amounts of DNA adducts formed in vivo also gives valuable information regarding the mutational effects that may result from particular exposures. The power of mass spectrometry (MS) to achieve qualitative and quantitative analyses of human DNA adducts has increased greatly in recent years with the development of improved chromatographic interfaces and ionisation sources. Adducts have been detected on nucleic acid bases, 2'-deoxynucleosides or 2'-deoxynucleotides, with LC-MS/MS being the favoured technique for many of these analyses. Our current applications of this technique include the determination of N7-(2-carbamoyl-2-hydroxyethyl)-guanine, which was postulated to be found as a DNA repair product in urine following exposure to acrylamide, and of 8-oxo-7,8-dihydro-2'-deoxyguanosine and 8-oxo-7,8-dihydro-2'-deoxyadenosine, as markers of oxidative damage in human lymphocyte DNA. Higher sensitivity (with a detection limit of 1-10 adducts/10(12) nucleotides) may be achieved by the use of accelerator mass spectrometry (AMS), although this requires the presence of certain isotopes, such as [(14)C], in the material being analysed. In order to make this technique more amenable for studies of human exposure to environmental carcinogens, new postlabelling techniques, incorporating [(14)C] into specific DNA adducts after formation, are being developed. It is expected that combining the use of advanced MS techniques with existing (32)P-postlabelling and immunochemical methodologies will contribute greatly to the understanding of the burden of human exposure to environmental carcinogens.

  14. DNA adducts: Mass spectrometry methods and future prospects

    SciTech Connect

    Farmer, P.B. . E-mail: pbf1@le.ac.uk; Brown, K.; Tompkins, E.; Emms, V.L.; Jones, D.J.L.; Singh, R.; Phillips, D.H.

    2005-09-01

    Detection of DNA adducts is widely used for the monitoring of exposure to genotoxic carcinogens. Knowledge of the nature and amounts of DNA adducts formed in vivo also gives valuable information regarding the mutational effects that may result from particular exposures. The power of mass spectrometry (MS) to achieve qualitative and quantitative analyses of human DNA adducts has increased greatly in recent years with the development of improved chromatographic interfaces and ionisation sources. Adducts have been detected on nucleic acid bases, 2'-deoxynucleosides or 2'-deoxynucleotides, with LC-MS/MS being the favoured technique for many of these analyses. Our current applications of this technique include the determination of N7-(2-carbamoyl-2-hydroxyethyl)-guanine, which was postulated to be found as a DNA repair product in urine following exposure to acrylamide, and of 8-oxo-7,8-dihydro-2'-deoxyguanosine and 8-oxo-7,8-dihydro-2'-deoxyadenosine, as markers of oxidative damage in human lymphocyte DNA. Higher sensitivity (with a detection limit of 1-10 adducts/10{sup 12} nucleotides) may be achieved by the use of accelerator mass spectrometry (AMS), although this requires the presence of certain isotopes, such as [{sup 14}C], in the material being analysed. In order to make this technique more amenable for studies of human exposure to environmental carcinogens, new postlabelling techniques, incorporating [{sup 14}C] into specific DNA adducts after formation, are being developed. It is expected that combining the use of advanced MS techniques with existing {sup 32}P-postlabelling and immunochemical methodologies will contribute greatly to the understanding of the burden of human exposure to environmental carcinogens.

  15. Lactoperoxidase-catalyzed activation of carcinogenic aromatic and heterocyclic amines.

    PubMed

    Gorlewska-Roberts, Katarzyna M; Teitel, Candee H; Lay, Jackson O; Roberts, Dean W; Kadlubar, Fred F

    2004-12-01

    Lactoperoxidase, an enzyme secreted from the human mammary gland, plays a host defensive role through antimicrobial activity. It has been implicated in mutagenic and carcinogenic activation in the human mammary gland. The potential role of heterocyclic and aromatic amines in the etiology of breast cancer led us to examination of the lactoperoxidase-catalyzed activation of the most commonly studied arylamine carcinogens: 2-amino-1-methyl-6-phenylimidazo[4,5-b]-pyridine (PhIP), benzidine, 4-aminobiphenyl (ABP), 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), and 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx). In vitro activation was performed with lactoperoxidase (partially purified from bovine milk or human milk) in the presence of hydrogen peroxide and calf thymus DNA. Products formed during enzymatic activation were monitored by HPLC with ultraviolet and radiometric detection. Two of these products were characterized as hydrazo and azo derivatives by means of mass spectrometry. The DNA binding level of 3H- and 14C-radiolabeled amines after peroxidase-catalyzed activation was dependent on the hydrogen peroxide concentration, and the highest levels of carcinogen binding to DNA were observed at 100 microM H2O2. Carcinogen activation and the level of binding to DNA were in the order of benzidine > ABP > IQ > MeIQx > PhIP. One of the ABP adducts was identified, and the level at which it is formed was estimated to be six adducts/10(5) nucleotides. The susceptibility of aromatic and heterocyclic amines for lactoperoxidase-catalyzed activation and the binding levels of activated products to DNA suggest a potential role of lactoperoxidase-catalyzed activation of carcinogens in the etiology of breast cancer.

  16. Malondialdehyde-acetaldehyde-adducted protein inhalation causes lung injury.

    PubMed

    Wyatt, Todd A; Kharbanda, Kusum K; McCaskill, Michael L; Tuma, Dean J; Yanov, Daniel; DeVasure, Jane; Sisson, Joseph H

    2012-02-01

    In addition to cigarette smoking, alcohol exposure is also associated with increased lung infections and decreased mucociliary clearance. However, little research has been conducted on the combination effects of alcohol and cigarette smoke on lungs. Previously, we have demonstrated in a mouse model that the combination of cigarette smoke and alcohol exposure results in the formation of a very stable hybrid malondialdehyde-acetaldehyde (MAA)-adducted protein in the lung. In in vitro studies, MAA-adducted protein stimulates bronchial epithelial cell interleukin-8 (IL-8) via the activation of protein kinase C epsilon (PKCɛ). We hypothesized that direct MAA-adducted protein exposure in the lungs would mimic such a combination of smoke and alcohol exposure leading to airway inflammation. To test this hypothesis, C57BL/6J female mice were intranasally instilled with either saline, 30μL of 50μg/mL bovine serum albumin (BSA)-MAA, or unadducted BSA for up to 3 weeks. Likewise, human lung surfactant proteins A and D (SPA and SPD) were purified from human pulmonary proteinosis lung lavage fluid and successfully MAA-adducted in vitro. Similar to BSA-MAA, SPD-MAA was instilled into mouse lungs. Lungs were necropsied and assayed for histopathology, PKCɛ activation, and lung lavage chemokines. In control mice instilled with saline, normal lungs had few inflammatory cells. No significant effects were observed in unadducted BSA- or SPD-instilled mice. However, when mice were instilled with BSA-MAA or SPD-MAA for 3 weeks, a significant peribronchiolar localization of inflammatory cells was observed. Both BSA-MAA and SPD-MAA stimulated increased lung lavage neutrophils and caused a significant elevation in the chemokine, keratinocyte chemokine, which is a functional homologue to human IL-8. Likewise, MAA-adducted protein stimulated the activation of airway and lung slice PKCɛ. These data support that the MAA-adducted protein induces a proinflammatory response in the lungs and

  17. Quantitation of DNA Adducts Induced by 1,3-Butadiene

    NASA Astrophysics Data System (ADS)

    Sangaraju, Dewakar; Villalta, Peter W.; Wickramaratne, Susith; Swenberg, James; Tretyakova, Natalia

    2014-07-01

    Human exposure to 1,3-butadiene (BD) present in automobile exhaust, cigarette smoke, and forest fires is of great concern because of its potent carcinogenicity. The adverse health effects of BD are mediated by its epoxide metabolites such as 3,4-epoxy-1-butene (EB), which covalently modify genomic DNA to form promutagenic nucleobase adducts. Because of their direct role in cancer, BD-DNA adducts can be used as mechanism-based biomarkers of BD exposure. In the present work, a mass spectrometry-based methodology was developed for accurate, sensitive, and precise quantification of EB-induced N-7-(1-hydroxy-3-buten-2-yl) guanine (EB-GII) DNA adducts in vivo. In our approach, EB-GII adducts are selectively released from DNA backbone by neutral thermal hydrolysis, followed by ultrafiltration, offline HPLC purification, and isotope dilution nanoLC/ESI+-HRMS3 analysis on an Orbitrap Velos mass spectrometer. Following method validation, EB-GII lesions were quantified in human fibrosarcoma (HT1080) cells treated with micromolar concentrations of EB and in liver tissues of rats exposed to sub-ppm concentrations of BD (0.5-1.5 ppm). EB-GII concentrations increased linearly from 1.15 ± 0.23 to 10.11 ± 0.45 adducts per 106 nucleotides in HT1080 cells treated with 0.5-10 μM DEB. EB-GII concentrations in DNA of laboratory rats exposed to 0.5, 1.0, and 1.5 ppm BD were 0.17 ± 0.05, 0.33 ± 0.08, and 0.50 ± 0.04 adducts per 106 nucleotides, respectively. We also used the new method to determine the in vivo half-life of EB-GII adducts in rat liver DNA (2.20 ± 0.12 d) and to detect EB-GII in human blood DNA. To our knowledge, this is the first application of nanoLC/ESI+-HRMS3 Orbitrap methodology to quantitative analysis of DNA adducts in vivo.

  18. Chemistry and Biology of Aflatoxin-DNA Adducts

    SciTech Connect

    Stone, Michael P.; Banerjee, Surajit; Brown, Kyle L.; Egli, Martin

    2012-03-27

    Aspergillus flavus is a fungal contaminant of stored rice, wheat, corn, and other grainstuffs, and peanuts. This is of concern to human health because it produces the mycotoxin aflatoxin B{sub 1} (AFB{sub 1}), which is genotoxic and is implicated in the etiology of liver cancer. AFB{sub 1} is oxidized in vivo by cytochrome P450 to form aflatoxin B{sub 1} epoxide, which forms an N7-dG adduct (AFB{sub 1}-N7-dG) in DNA. The latter rearranges to a formamidopyrimidine (AFB{sub 1}-FAPY) derivative that equilibrates between {alpha} and {beta} anomers of the deoxyribose. In DNA, both the AFB{sub 1}-N7-dG and AFB{sub 1}-{beta}-FAPY adducts intercalate above the 5'-face of the damaged guanine. Each produces G {yields} T transversions in Escherichia coli, but the AFB{sub 1}-{beta}-FAPY adduct is more mutagenic. The Sulfolobus solfataricus P2 DNA polymerase IV (Dpo4) provides a model for understanding error-prone bypass of the AFB{sub 1}-N7-dG and AFB{sub 1}-{beta}-FAPY adducts. It bypasses the AFB{sub 1}-N7-dG adduct, but it conducts error-prone replication past the AFB{sub 1}-FAPY adduct, including mis-insertion of dATP, consistent with the G {yields} T mutations characteristic of AFB{sub 1} mutagenesis in E. coli. Crystallographic analyses of a series of binary and ternary complexes with the Dpo4 polymerase revealed differing orientations of the N7-C8 bond of the AFB{sub 1}-N7-dG adduct as compared to the N{sup 5}-C8 bond in the AFB{sub 1}-{beta}-FAPY adduct, and differential accommodation of the intercalated AFB{sub 1} moieties within the active site. These may modulate AFB{sub 1} lesion bypass by this polymerase.

  19. A Cyclic Disilylated Stannylene: Synthesis, Dimerization, and Adduct Formation

    PubMed Central

    2011-01-01

    Reaction of 1,4-dipotassio-1,1,4,4-tetrakis(trimethylsilyl)tetramethyltetrasilane with [(Me3Si)2N]2Sn led to the formation of an endocyclic distannene via the dimerization of a transient stannylene. In the presence of strong donor molecules such as PEt3, the stannylene could be trapped as adduct. Reaction of the PEt3 derivative with B(C6F5)3 gave rise to the formation of the stannylene B(C6F5)3 adduct. PMID:21438553

  20. Laboratory studies of weakly bound adducts of atmospheric interest

    SciTech Connect

    Wine, P.H.; Nicovich, J.M.; Stickel, R.E.; Hynes, A.J.

    1995-12-31

    It is now well-established that weakly bound adducts, i.e., species whose life-times toward unimolecular decomposition are only fractions of a second under atmospheric conditions, play an important role in tropospheric sulfur chemistry. In this presentation, recent results from our laboratory concerning the existence and atmospheric fates of two such weakly bound species, (CH{sub 3}){sub 2}S-OH and (CH{sub 3}){sub 2}S-Cl, will be discussed. In addition, evidence for the formation of weakly bound adducts in reactions of chlorine atoms with methyl halides will be presented.

  1. Possible rare congenital dysinnervation disorder: congenital ptosis associated with adduction.

    PubMed

    Mendes, Sílvia; Beselga, Diana; Campos, Sónia; Neves, Arminda; Campos, Joana; Carvalho, Sílvia; Silva, Eduardo; Castro Sousa, João Paulo

    2015-01-01

    Ptosis is defined as an abnormally low position of the upper eyelid margin. It can be congenital or acquired, uni or bilateral, and isolated or associated with other ocular and nonocular defects. We report a case of a female child, aged 8 years, with congenital right ptosis increased on right adduction and with left ptosis on left adduction. There was no horizontal ocular movement limitation. Apparent underaction of the right inferior oblique muscle was also present. We believe that within the possible mechanisms it is more likely that it is a congenital innervation dysgenesis syndrome (CID)/congenital cranial dysinnervation disorder (CCDD).

  2. Polyimidazoles via aromatic nucleophilic displacement

    NASA Technical Reports Server (NTRS)

    Connell, John W. (Inventor); Hergenrother, Paul M. (Inventor)

    1991-01-01

    Polyimidazoles (Pl) are prepared by the aromatic nucleophilic displacement reaction of di(hydroxyphenyl)imidazole monomers with activated aromatic dihalides or activated aromatic dinitro compounds. The reactions are carried out in polar aprotic solvents such as N,N-dimethylacetamide, sulfolane, N-methylpyrroldinone, dimethylsulfoxide, or diphenylsulfone using alkali metal bases such as potassium carbonate at elevated temperature under nitrogen. The di(hydroxyphenyl)imidazole monomers are prepared by reacting an aromatic aldehyde with a dimethoxybenzil or by reacting an aromatic dialdehyde with a methoxybenzil in the presence of ammonium acetate. The di(methoxyphenyl)imidazole is subsequently treated with aqueous hydrobromic acid to give the di(hydroxyphenyl)imidazole monomer. This synthetic route has provided high molecular weight Pl of new chemical structure, is economically and synthetically more favorable than other routes, and allows for facile chemical structure variation due to the availability of a large variety of activated aromatic dihalides and dinitro compounds.

  3. Polyimidazoles via aromatic nucleophilic displacement

    NASA Technical Reports Server (NTRS)

    Connell, John W. (Inventor); Hergenrother, Paul M. (Inventor)

    1992-01-01

    Polyimidazoles (PI) are prepared by the aromatic nucleophilic displacement reaction of di(hydroxyphenyl) imidazole monomers with activated aromatic dihalides or activated aromatic dinitro compounds. The reactions are carried out in polar aprotic solvents such as N,N-dimethyl acetamide, sulfolane, N-methylpyrrolidinone, dimethylsulfoxide, or diphenylsulfone using alkali metal bases such as potassium carbonate at elevated temperatures under nitrogen. The di(hydroxyphenyl) imidazole monomers are prepared by reacting an aromatic aldehyde with a dimethoxybenzil or by reacting an aromatic dialdehyde with a methoxybenzil in the presence of ammonium acetate. The di(methoxyphenyl) imidazole is subsequently treated with aqueous hydrobromic acid to give the di(hydroxphenyl) imidazole monomer. This synthetic route has provided high molecular weight PI of new chemical structure, is economically and synthetically more favorable than other routes, and allows for facile chemical structure variation due to the availability of a large variety of activated aromatic dihalides and dinitro compounds.

  4. Insights into the error bypass of 1-Nitropyrene DNA adduct by DNA polymerase ι: A QM/MM study

    NASA Astrophysics Data System (ADS)

    Li, Yanwei; Bao, Lei; Zhang, Ruiming; Tang, Xiaowen; Zhang, Qingzhu; Wang, Wenxing

    2017-10-01

    The error bypass mechanism of DNA polymerase ι toward N-(deoxyguanosin-8-yl)-1-aminopyrene adduction was studied by using quantum mechanics/molecular mechanics method. The most favorable mechanism highlights three elementary steps: proton transfer from dC to dATP, phosphoryl transfer, and deprotonation of dAMP. The phosphoryl transfer step was found to be rate-determining. The calculated average barrier (23.8 kcal mol-1) is in accordance with the experimental value (21.5 kcal mol-1). Electrostatic influence analysis indicates that residues Asp126 and Lys207 significantly suppress the error bypass while Glu127 facilitates the process. These results highlight the origins of the mutagenicity of nitrated polycyclic aromatic hydrocarbons in molecular detail.

  5. Strategy for identifying unknown hemoglobin adducts using adductome LC-MS/MS data: Identification of adducts corresponding to acrylic acid, glyoxal, methylglyoxal, and 1-octen-3-one.

    PubMed

    Carlsson, Henrik; Törnqvist, Margareta

    2016-06-01

    Electrophilic compounds have the ability to form adducts with nucleophilic sites in proteins and DNA in tissues, and thereby constitute risks for toxic effects. Adductomic approaches are developed for systematic screening of adducts to DNA and blood proteins, with the aim to detect unknown internal exposures to electrophiles. In a previous adductomic screening of adducts to N-terminals in hemoglobin, using LC-MS/MS, 19 unknown adducts were detected in addition to seven previously identified adducts. The present paper describes the identification of four of these unknown adducts, as well as the strategy used to identify them. Using LC-MS data from the screening, hypotheses about adduct identities were formulated: probable precursor electrophiles with matching molecular weights were suggested based on the molecular weights of the modifications and the retention times of the analytes, in combination with comparisons of theoretical Log P calculations and databases. Reference adducts were generated by incubation of blood samples with the hypothesized precursor electrophiles. The four identified precursor electrophiles, corresponding to the observed unknown adducts, were glyoxal, methylglyoxal, acrylic acid and 1-octen-3-one. Possible origins/exposure sources and toxicological information concerning the electrophilic precursors are discussed. The identified adducts could be explored as possible biomarkers for exposure.

  6. Protein adduct species in muscle and liver of rats following acute ethanol administration.

    PubMed

    Patel, Vinood B; Worrall, Simon; Emery, Peter W; Preedy, Victor R

    2005-01-01

    Previous immunohistochemical studies have shown that the post-translational formation of aldehyde-protein adducts may be an important process in the aetiology of alcohol-induced muscle disease. However, other studies have shown that in a variety of tissues, alcohol induces the formation of various other adduct species, including hybrid acetaldehyde-malondialdehyde-protein adducts and adducts with free radicals themselves, e.g. hydroxyethyl radical (HER)-protein adducts. Furthermore, acetaldehyde-protein adducts may be formed in reducing or non-reducing environments resulting in distinct molecular entities, each with unique features of stability and immunogenicity. Some in vitro studies have also suggested that unreduced adducts may be converted to reduced adducts in situ. Our objective was to test the hypothesis that in muscle a variety of different adduct species are formed after acute alcohol exposure and that unreduced adducts predominate. Rabbit polyclonal antibodies were raised against unreduced and reduced aldehydes and the HER-protein adducts. These were used to assay different adduct species in soleus (type I fibre-predominant) and plantaris (type II fibre-predominant) muscles and liver in four groups of rats administered acutely with either [A] saline (control); [B] cyanamide (an aldehyde dehydrogenase inhibitor); [C] ethanol; [D] cyanamide+ethanol. Amounts of unreduced acetaldehyde and malondialdehyde adducts were increased in both muscles of alcohol-dosed rats. However there was no increase in the amounts of reduced acetaldehyde adducts, as detected by both the rabbit polyclonal antibody and the RT1.1 mouse monoclonal antibody. Furthermore, there was no detectable increase in malondialdehyde-acetaldehyde and HER-protein adducts. Similar results were obtained in the liver. Adducts formed in skeletal muscle and liver of rats exposed acutely to ethanol are mainly unreduced acetaldehyde and malondialdehyde species.

  7. UNUSUALLY STABLE ADDUCT BETWEEN METHANOLYZED AMOXICILLIN OR AMPICILLIN AND THEIR DIKETOPIPERAZINE DERIVATIVES.

    PubMed

    Kosińska, Katarzyna; Frański, Rafał; Frańska, Magdalena

    2016-01-01

    Amoxicillin and ampicillin were subjected to methanolysis. As expected, the methanolysis products were observed by HPLC-ESI-MS. Besides these products, diketopiperazine derivatives were also detected. Additionally, unusually stable adduct formed between the products of methanolysis and diketopiperazine derivatives was also identified. Analogical adducts were detected when ethanolysis was performed instead of methanolysis. HPLC-ESI-MS analysis of the separated adducts confirmed that the adducts were composed of methanolysis products and diketopiperazine derivatives.

  8. Immunochemical and Biochemical Analysis of Adducts to DNA and Proteins After Exposure to Sulfur Mustard

    DTIC Science & Technology

    1993-05-13

    cQ.00o~33/o/ /9 IMMUNOCHEMICAL AND BIOCHEMICAL ANALYSIS OF O• ADDUCTS TO DNA AND PROTEINS AFTER EXPOSURE TO SULFUR MUSTARD _ == M G.P. van der Schans...chosen to define exposure to sulfur mustard (HD), based on immunochemical analysis of adducts of HD to DNA and proteins. These adducts are agent...calibration of the immunochemical assays. Analogous to HD-DNA adducts , reaction products with blood proteins may be used to establish HD exposure. Since it

  9. Contorted polycyclic aromatics.

    PubMed

    Ball, Melissa; Zhong, Yu; Wu, Ying; Schenck, Christine; Ng, Fay; Steigerwald, Michael; Xiao, Shengxiong; Nuckolls, Colin

    2015-02-17

    CONSPECTUS: This Account describes a body of research in the design, synthesis, and assembly of molecular materials made from strained polycyclic aromatic molecules. The strain in the molecular subunits severely distorts the aromatic molecules away from planarity. We coined the term "contorted aromatics" to describe this class of molecules. Using these molecules, we demonstrate that the curved pi-surfaces are useful as subunits to make self-assembled electronic materials. We have created and continue to study two broad classes of these "contorted aromatics": discs and ribbons. The figure that accompanies this conspectus displays the three-dimensional surfaces of a selection of these "contorted aromatics". The disc-shaped contorted molecules have well-defined conformations that create concave pi-surfaces. When these disc-shaped molecules are substituted with hydrocarbon side chains, they self-assemble into columnar superstructures. Depending on the hydrocarbon substitution, they form either liquid crystalline films or macroscopic cables. In both cases, the columnar structures are photoconductive and form p-type, hole- transporting materials in field effect transistor devices. This columnar motif is robust, allowing us to form monolayers of these columns attached to the surface of dielectrics such as silicon oxide. We use ultrathin point contacts made from individual single-walled carbon nanotubes that are separated by a few nanometers to probe the electronic properties of short stacks of a few contorted discs. We find that these materials have high mobility and can sense electron-deficient aromatic molecules. The concave surfaces of these disc-shaped contorted molecules form ideal receptors for the molecular recognition and assembly with spherical molecules such as fullerenes. These interfaces resemble ball-and-socket joints, where the fullerene nests itself in the concave surface of the contorted disc. The tightness of the binding between the two partners can be

  10. Aromatic molecules as spintronic devices

    SciTech Connect

    Ojeda, J. H.; Orellana, P. A.; Laroze, D.

    2014-03-14

    In this paper, we study the spin-dependent electron transport through aromatic molecular chains attached to two semi-infinite leads. We model this system taking into account different geometrical configurations which are all characterized by a tight binding Hamiltonian. Based on the Green's function approach with a Landauer formalism, we find spin-dependent transport in short aromatic molecules by applying external magnetic fields. Additionally, we find that the magnetoresistance of aromatic molecules can reach different values, which are dependent on the variations in the applied magnetic field, length of the molecules, and the interactions between the contacts and the aromatic molecule.

  11. Temporal changes in CYP1A, DNA adducts, and contaminant residues in fish removed from contaminated sites

    SciTech Connect

    Anulacion, B.F.; Hom, T.; Reichert, W.L.; Collier, T.K.

    1995-12-31

    In combined field and laboratory studies, English sole (Parophrys vetulus) were captured from two highly polluted areas and from a relatively, uncontaminated area. The Duwamish Waterway contains a variety of contaminants, including polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs), whereas the other contaminated area, Eagle Harbor, is contaminated primarily with creosote-derived PAHs. Fish were sampled at time of capture for analyses of several biomarkers of contaminant exposure and effects, including hepatic cytochrome P4501A (CYP1A), biliary fluorescent aromatic compounds (FACs), liver, muscle, and brain PCBs, and levels of hepatic DNA adducts. Remaining fish were transported to the laboratory, maintained in clean flowing seawater, and sampled after 3, 7, 14, 21, 28, 42, and 56 days. CYP1A and biliary FACs declined steadily in fish removed from the polluted areas. Estimated half-lives ranged from 14 to 16 days for CYP1A and 12 to 28 days for biliary FACs. PCB levels in the liver tended to increase over time, suggesting that PCBs were not primarily responsible for induction of hepatic CYP1A in these fish. PCBs in the brain showed a similar increase with time, while PCBs in muscle tissue decreased. Half-lives of hepatic DNA adducts ranged from 40--100 days. There were no substantial differences in biomarker half-lives between the two polluted areas. These results are consistent with earlier laboratory studies, and assist in interpreting results of field surveys of contaminant exposure and effects in aquatic organisms. Subsequent to this study, Eagle Harbor has undergone remediation by capping, and the results of this work will enhance the assessment of the efficacy of this effort.

  12. 40 CFR 721.6205 - Hexamethylenediamine adduct of substituted piperidinyloxy (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Hexamethylenediamine adduct of... Significant New Uses for Specific Chemical Substances § 721.6205 Hexamethylenediamine adduct of substituted... substance identified generically as hexamethylenediamine adduct of substituted piperidinyloxy (PMN P-99-0510...

  13. 40 CFR 721.6205 - Hexamethylenediamine adduct of substituted piperidinyloxy (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Hexamethylenediamine adduct of... Significant New Uses for Specific Chemical Substances § 721.6205 Hexamethylenediamine adduct of substituted... substance identified generically as hexamethylenediamine adduct of substituted piperidinyloxy (PMN P-99-0510...

  14. 40 CFR 721.1850 - Toluene sulfonamide bis-phe-nol A epoxy adduct.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... epoxy adduct. 721.1850 Section 721.1850 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.1850 Toluene sulfonamide bis-phe-nol A epoxy adduct. (a) Chemical... as toluene sulfonamide bisphenol A epoxy adduct (PMN P-90-113) is subject to reporting under...

  15. Volatile Barium Beta-Diketonate Polyether Adducts. Synthesis, Characterization and Metalorganic Chemical Vapor Deposition

    DTIC Science & Technology

    1991-05-31

    Volatile Barium 13- Diketonate Polyether Adducts.... Synthesis , Characterization and Metalorganic Chemical Vapor Deposition by Robin A. Gardiner...has been approved for public release and sale: its distribution is unlimited. Volatile, Barium B- Diketonate Polyether Adducts. Synthesis ...NO. NO. INO. ACCESSION NO. Arlington, VA 22217 II 11. TITLE (include Security Classification) Volatile Barium B- Diketonate Polyether Adducts

  16. 40 CFR 721.3680 - Ethylene oxide adduct of fatty acid ester with pentaerythritol.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Ethylene oxide adduct of fatty acid... New Uses for Specific Chemical Substances § 721.3680 Ethylene oxide adduct of fatty acid ester with... identified generically as ethylene oxide adduct of fatty acid ester with pentaerythritol (PMN P-91-442)...

  17. 40 CFR 721.3680 - Ethylene oxide adduct of fatty acid ester with pentaerythritol.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Ethylene oxide adduct of fatty acid... New Uses for Specific Chemical Substances § 721.3680 Ethylene oxide adduct of fatty acid ester with... identified generically as ethylene oxide adduct of fatty acid ester with pentaerythritol (PMN P-91-442)...

  18. 40 CFR 721.3680 - Ethylene oxide adduct of fatty acid ester with pentaerythritol.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Ethylene oxide adduct of fatty acid... New Uses for Specific Chemical Substances § 721.3680 Ethylene oxide adduct of fatty acid ester with... identified generically as ethylene oxide adduct of fatty acid ester with pentaerythritol (PMN P-91-442)...

  19. 40 CFR 721.3680 - Ethylene oxide adduct of fatty acid ester with pentaerythritol.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Ethylene oxide adduct of fatty acid... New Uses for Specific Chemical Substances § 721.3680 Ethylene oxide adduct of fatty acid ester with... identified generically as ethylene oxide adduct of fatty acid ester with pentaerythritol (PMN P-91-442)...

  20. 40 CFR 721.3680 - Ethylene oxide adduct of fatty acid ester with pentaerythritol.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Ethylene oxide adduct of fatty acid... New Uses for Specific Chemical Substances § 721.3680 Ethylene oxide adduct of fatty acid ester with... identified generically as ethylene oxide adduct of fatty acid ester with pentaerythritol (PMN P-91-442)...

  1. Fluorinated aromatic diamine

    NASA Technical Reports Server (NTRS)

    Jones, Robert J. (Inventor); O'Rell, Michael K. (Inventor); Hom, Jim M. (Inventor)

    1980-01-01

    This invention relates to a novel aromatic diamine and more particularly to the use of said diamine for the preparation of thermally stable high-molecular weight polymers including, for example, polyamides, polyamideimides, polyimides, and the like. This diamine is obtained by reacting a stoichometric amount of a disodium salt of 2,2-bis(4-hydroxyphenyl) hexafluoropropane with 4-chloronitrobenzene to obtain an intermediate, 2,2-bis[4-(4-nitrophenoxy)phenyl] hexafluoropropane, which is reduced to the corresponding 2,2-bis[4-(4-aminophenoxy)phenyl] hexafluoropropane.

  2. Nitrogen oxides as dopants for the detection of aromatic compounds with ion mobility spectrometry.

    PubMed

    Gaik, Urszula; Sillanpää, Mika; Witkiewicz, Zygfryd; Puton, Jarosław

    2017-03-03

    Limits of detection (LODs) in ion mobility spectrometry (IMS) strictly depend on ionization of the analyte. Especially challenging is ionization of compounds with relatively low proton affinity (PA) such as aromatic compounds. To change the course of ion-molecule reactions and enhance the performance of the IMS spectrometer, substances called dopants are introduced into the carrier gas. In this work, we present the results of studies of detection using nitrogen oxides (NOx) dopants. Three aromatic compounds, benzene, toluene, toluene diisocyanate and, for comparison, two compounds with high PA, dimethyl methylphosphonate (DMMP) and triethyl phosphate (TEP), were selected as analytes. The influence of water vapour on these analyses was also studied. Experiments were carried out with a generator of gas mixtures that allowed for the simultaneous introduction of three substances into the carrier gas. The experiments showed that the use of NOx dopants significantly decreases LODs for aromatic compounds and does not affect the detection of compounds with high PA. The water vapour significantly disturbs the detection of aromatic compounds; however, doping with NOx allows to reduce the effect of humidity. Graphical Abstract Two possible ionization mechanisms of aromatic compounds in ion mobility spectrometry: proton transfer reaction and adduct formation.

  3. NMR at the Picomole Level of a DNA Adduct

    PubMed Central

    Kautz, Roger; Wang, Poguang; Giese, Roger W.

    2014-01-01

    We investigate the limit of detection for obtaining NMR data of a DNA adduct using modern microscale NMR instrumentation, once the adduct has been isolated at the pmol level. Eighty nanograms (130 pmol) of a DNA adduct standard, N-(2′-deoxyguanosin-8-yl)-2-acetylaminofluorene 5′-monophosphate (AAF-dGMP), in 1.5 μL of D2O with 10% methanol-d4, in a vial, was completely picked up as a droplet suspended in a fluorocarbon liquid, and loaded efficiently into a microcoil probe. This work demonstrates a practical manual method of droplet microfluidic sample loading, previously demonstrated using automated equipment, which provides a several-fold advantage over conventional flow injection. Eliminating dilution during injection and confining the sample into the observed volume realizes the full theoretical mass sensitivity of a microcoil, comparable to a micro-cryo probe. With 80 ng, an NMR spectrum acquired over 40 hr showed all of the resonances seen in a standard spectrum of AAF-dGMP, with a S/N of at least 10, despite broadening due to previously-noted effects of conformational exchange. Also a 2D TOCSY spectrum (total correlation spectroscopy) was acquired on 1.6 μg in 18 hr. This work helps to define the utility of NMR in combination with other analytical methods for the structural characterization of a small amount of a DNA adduct. PMID:24028148

  4. 40 CFR 721.4590 - Mannich-based adduct.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    .... Requirements as specified in § 721.80(h). (ii) Release to water. Requirements as specified in § 721.90 (a)(4... reporting. (1) The chemical substance generically identified as a Mannich-based adduct (PMN P-93-66) is...

  5. Theoretical investigations on the formation of nitrobenzanthrone-DNA adducts.

    PubMed

    Arlt, Volker M; Phillips, David H; Reynisson, Jóhannes

    2011-09-07

    3-Nitrobenzanthrone (3-NBA) is a potent mutagen and suspected human carcinogen identified in diesel exhaust. The thermochemical formation cascades were calculated for six 3-NBA-derived DNA adducts employing its arylnitrenium ion as precursor using density functional theory (DFT). Clear exothermic pathways were found for four adducts, i.e., 2-(2'-deoxyadenosin-N(6)-yl)-3-aminobenzanthrone, 2-(2'-deoxyguanosin-N(2)-yl)-3-aminobenzanthrone, N-(2'-deoxyguanosin-8-yl)-3-aminobenzanthrone and 2-(2'-deoxyguanosin-8-yl)-3-aminobenzanthrone. All four have been observed to be formed in cell-free experimental systems. The formation of N-(2'-deoxyadenosin-8-yl)-3-aminobenzanthrone is predicted to be not thermochemically viable explaining its absence in either in vitro or in vivo model systems. However, 2-(2'-deoxyadenosin-8-yl)-3-aminobenzanthrone, can be formed, albeit not as a major product, and is a viable candidate for an unknown adenine adduct observed experimentally. 2-nitrobenzanthrone (2-NBA), an isomer of 3-NBA, was also included in the calculations; it has a higher abundance in ambient air than 3-NBA, but a much lower genotoxic potency. Similar thermochemical profiles were obtained for the calculated 2-NBA-derived DNA adducts. This leads to the conclusion that enzymatic activation as well as the stability of its arylnitrenium ion are important determinants of 2-NBA genotoxicity.

  6. 2'-Deoxythymidine adducts from the anti-HIV drug nevirapine.

    PubMed

    Antunes, Alexandra M M; Wolf, Benjamin; Oliveira, M Conceição; Beland, Frederick A; Marques, M Matilde

    2013-04-26

    Nevirapine (NVP) is a non-nucleoside reverse transcriptase inhibitor (NNRTI) used against HIV-1. Currently, NVP is the most widely used anti-HIV drug in developing countries, both in combination therapy and to prevent mother-to-child transmission of HIV. Despite its efficacy against HIV, NVP produces a variety of toxic responses, including hepatotoxicity and skin rash. It is also associated with increased incidences of hepatoneoplasias in rodents. In addition, epidemiological data suggest that NNRTI use is a risk factor for non-AIDS-defining cancers in HIV-positive patients. Current evidence supports the involvement of metabolic activation to reactive electrophiles in NVP toxicity. NVP metabolism includes oxidation to 12-hydroxy-NVP; subsequent Phase II sulfonation produces an electrophilic metabolite, 12-sulfoxy-NVP, capable of reacting with DNA to yield covalent adducts. Since 2'-deoxythymidine (dT) adducts from several alkylating agents are regarded as having significant mutagenic/carcinogenic potential, we investigated the formation of NVP-dT adducts under biomimetic conditions. Toward this goal, we initially prepared and characterized synthetic NVP-dT adduct standards using a palladium-mediated Buchwald-Hartwig coupling strategy. The synthetic standards enabled the identification, by LC-ESI-MS, of 12-(2'-deoxythymidin-N3-yl)-nevirapine (N3-NVP-dT) in the enzymatic hydrolysate of salmon testis DNA reacted with 12-mesyloxy-NVP, a synthetic surrogate for 12-sulfoxy-NVP. N3-NVP-dT, a potentially cytotoxic and mutagenic DNA lesion, was also the only dT-specific adduct detected upon reaction of dT with 12-mesyloxy-NVP. Our data suggest that N3-NVP-dT may be formed in vivo and play a role in the hepatotoxicity and/or putative hepatocarcinogenicity of NVP.

  7. Quantification of Carnosine-Aldehyde Adducts in Human Urine.

    PubMed

    da Silva Bispo, Vanderson; Di Mascio, Paolo; Medeiros, Marisa

    2014-10-01

    Lipid peroxidation generates several reactive carbonyl species, including 4-hydroxy-2-nonenal (HNE), acrolein (ACR), 4-hydroxy-2-hexenal (HHE) and malondialdehyde. One major pathwayof aldehydes detoxification is through conjugation with glutathione catalyzed by glutathione-S-transferases or, alternatively, by conjugation with endogenous histidine containing dipeptides, such as carnosine (CAR). In this study, on-line reverse-phase high-performance liquid chromatography (HPLC) separation with tandem mass spectrometry detection was utilized for the accurate quantification of CAR- ACR, CAR-HHE and CAR-HNE adducts in human urinary samples from non-smokers young adults. Standard adducts were prepared and isolated by HPLC. The results showed the presence of a new product from the reaction of CAR with ACR. This new adduct was completely characterized by HPLC/MS-MSn, 1H RMN, COSY and HSQC. The new HPLC/MS/MS methodology employing stable isotope-labeled internal standards (CAR-HHEd5 and CAR-HNEd11) was developed for adducts quantification. This methodology permits quantification of 10pmol CAR-HHE and 1pmol of CAR-ACR and CAR-HNE. Accurate determinations in human urine sample were performed and showed 4.65±1.71 to CAR-ACR, 5.13±1.76 to CAR-HHE and 5.99±3.19nmol/mg creatinine to CAR-HNE. Our results indicate that carnosine pathways can be an important detoxification route of a, ß -unsaturated aldehydes. Moreover, carnosine adducts may be useful as redox stress indicator. Copyright © 2014. Published by Elsevier Inc.

  8. Ion-molecule adduct formation in tandem mass spectrometry.

    PubMed

    Alechaga, Élida; Moyano, Encarnación; Galceran, Maria Teresa

    2016-02-01

    Nowadays most LC-MS methods rely on tandem mass spectrometry not only for quantitation and confirmation of compounds by multiple reaction monitoring (MRM), but also for the identification of unknowns from their product ion spectra. However, gas-phase reactions between charged and neutral species inside the mass analyzer can occur, yielding product ions at m/z values higher than that of the precursor ion, or at m/z values difficult to explain by logical losses, which complicate mass spectral interpretation. In this work, the formation of adduct ions in the mass analyzer was studied using several mass spectrometers with different mass analyzers (ion trap, triple quadrupole, and quadrupole-Orbitrap). Heterocyclic amines (AαC, MeAαC, Trp-P-1, and Trp-P-2), photo-initiators (BP and THBP), and pharmaceuticals (phenacetin and levamisole) were selected as model compounds and infused in LCQ Classic, TSQ Quantum Ultra AM, and Q-Exactive Orbitrap (ThermoFisher Scientific) mass spectrometers using electrospray as ionization method. The generation of ion-molecule adducts depended on the compound and also on the instrument employed. Adducts with neutral organic solvents (methanol and acetonitrile) were only observed in the ion trap instrument (LCQ Classic), because of the ionization source on-axis configuration and the lack of gas-phase barriers, which allowed inertial entrance of the neutrals into the analyzer. Adduct formation (only with water) in the triple quadrupole instruments was less abundant than in the ion trap and quadrupole-Orbitrap mass spectrometers, because of the lower residence time of the reactive product ions in the mass analyzer. The moisture level of the CID and/or damper gas had a great effect in beam-like mass analyzers such as triple quadrupole, but not in trap-like mass analyzers, probably because of the long residence time that allowed adduct formation even with very low concentrations of water inside the mass spectrometer.

  9. "Carbo-aromaticity" and novel carbo-aromatic compounds.

    PubMed

    Cocq, Kévin; Lepetit, Christine; Maraval, Valérie; Chauvin, Remi

    2015-09-21

    While the concept of aromaticity is being more and more precisely delineated, the category of "aromatic compounds" is being more and more expanded. This is illustrated by an introductory highlight of the various types of "aromaticity" previously invoked, and by a focus on the recently proposed "aromatic character" of the "two-membered rings" of the acetylene and butatriene molecules. This serves as a general foundation for the definition of "carbo-aromaticity", the relevance of which is surveyed through recent results in the synthetic, physical, and theoretical chemistry of carbo-mers and in particular macrocyclic-polycyclic representatives constituting a natural family of "novel aromatic compounds". With respect to their parent molecules, carbo-mers are constitutionally defined as "carbon-enriched", and can also be functionally regarded as "π-electron-enriched". This is exemplified by recent experimental and theoretical results on functional, aromatic, rigid, σ,π-macrocyclic carbo-benzene archetypes of various substitution patterns, with emphasis on the quadrupolar pattern. For the purpose of comparison, several types of non-aromatic references of carbo-benzenes are then considered, i.e. freely rotating σ,π-acyclic carbo-n-butadienes and flexible σ-cyclic, π-acyclic carbo-cyclohexadienes, and to "pro-aromatic" congeners, i.e. rigid σ,π-macrocyclic carbo-quinoids. It is shown that functional carbo-mers are entering the field of "molecular materials" for properties such as linear or nonlinear optical properties (e.g. dichromism and two-photon absorption) and single molecule conductivity. Since total or partial carbo-mers of aromatic carbon-allotropes of infinite size such as graphene (graphynes and graphdiynes) and graphite ("graphitynes") have long been addressed at the theoretical or conceptual level, recent predictive advances on the electrical, optical and mechanical properties of such carbo-materials are surveyed. Very preliminary experimental results

  10. Morita-Baylis-Hillman adducts: biological activities and potentialities to the discovery of new cheaper drugs.

    PubMed

    Lima-Junior, Claudio G; Vasconcellos, Mário L A A

    2012-07-01

    This review aims to present by the first time the Morita-Baylis-Hillman adducts (MBHA) as a new class of bioactive compounds and highlight its potentialities to the discovery of new cheaper and efficient drugs. Now, most these compounds can be prepared fast and on a single synthetic step (one-pot reaction) in high yields and using ecofriendly synthetic protocols. We highlight here the aromatic MBHA, which have shown diverse biological activities as anti-Leishmania chagasi and Leishmania amazonensis (parasites that cause cutaneous and visceral leishmaniasis), anti-Trypanosoma cruzi (parasite that cause Chagas disease), anti-Plasmodium falciparum and Plasmodium berghei (parasites that cause malaria), lethal against Biomphalaria glabrata (the snail transmitter of schistosomiasis), antibacterial, antifungal, herbicide and actives against some human tumor cell lines. Understanding of the biological mechanisms of action of this new class of molecules is still in the infancy stage. However, we report here which has been described to date on the possibilities of biological mechanisms of action, and we present new analyzes based on literature in this area. The academic and industrial interest in selecting green and cheaper experiments to the drugs development has been the prime mover of the growth on the subject.

  11. Photochemistry of psoralen-DNA adducts, biological effects of psoralen-DNA adducts, applications of psoralen-DNA photochemistry

    SciTech Connect

    Shi, Yun-bo

    1988-03-01

    This thesis consists of three main parts and totally eight chapters. In Part I, The author will present studies on the photochemistry of psoralen-DNA adducts, specifically, the wavelength dependencies for the photoreversals of thymidine-HMT (4'-hydroxymethyl-4, 5', 8-trimenthylpsoralen) monoadducts and diadduct and the same adducts incorporated in DNA helices and the wavelength dependecies for the photocrossslinking of thymidine-HMT monoadducts in double-stranded helices. In Part II, The author will report some biological effects of psoralen-DNA adducts, i.e., the effects on double-stranded DNA stability, DNA structure, and transcription by E. coli and T7 RNA polymerases. Finally, The author will focus on the applications of psoralen-DNA photochemistry to investigation of protein-DNA interaction during transcription, which includes the interaction of E. coli and T7 RNA polymerases with DNA in elongation complexes arrested at specific psoralen-DNA adduct sites as revealed by DNase I footprinting experiments. 123 refs., 52 figs., 12 tabs.

  12. Chloroethyinitrosourea-derived ethano cytosine and adenine adducts are substrates for escherichia coli glycosylases excising analogous etheno adducts

    SciTech Connect

    Guliaev, Anton B.; Singer, B.; Hang, Bo

    2004-05-05

    Exocyclic ethano DNA adducts are saturated etheno ring derivatives formed mainly by therapeutic chloroethylnitrosoureas (CNUs), which are also mutagenic and carcinogenic. In this work, we report that two of the ethano adducts, 3,N{sup 4}-ethanocytosine (EC) and 1,N{sup 6}-ethanoadenine (EA), are novel substrates for the Escherichia coli mismatch-specific uracil-DNA glycosylase (Mug) and 3-methyladenine DNA glycosylase II (AlkA), respectively. It has been shown previously that Mug excises 3,N{sup 4}-ethenocytosine ({var_epsilon}C) and AlkA releases 1,N{sup 6}-ethenoadenine ({var_epsilon}A). Using synthetic oligonucleotides containing a single ethano or etheno adduct, we found that both glycosylases had a {approx}20-fold lower excision activity toward EC or EA than that toward their structurally analogous {var_epsilon}C or {var_epsilon}A adduct. Both enzymes were capable of excising the ethano base paired with any of the four natural bases, but with varying efficiencies. The Mug activity toward EC could be stimulated by E. coli endonuclease IV and, more efficiently, by exonuclease III. Molecular dynamics (MD) simulations showed similar structural features of the etheno and ethano derivatives when present in DNA duplexes. However, also as shown by MD, the stacking interaction between the EC base and Phe 30 in the Mug active site is reduced as compared to the {var_epsilon}C base, which could account for the lower EC activity observed in this study.

  13. Analysis of Dibenzo[def,p]chrysene-Deoxyadenosine Adducts in Wild-Type and Cytochrome P450 1b1 Knockout Mice using Stable-Isotope Dilution UHPLC-MS/MS

    PubMed Central

    Harper, Tod A.; Morré, Jeff; Lauer, Fredine T.; McQuistan, Tammie J.; Hummel, Jessica M.; Burchiel, Scott W.; Williams, David E.

    2015-01-01

    The polycyclic aromatic hydrocarbon (PAH), dibenzo[def,p]chrysene (DBC; also known as dibenzo[a,l]pyrene), is a potent carcinogen in animal models and a class 2A human carcinogen. Recent investigations into DBC-mediated toxicity identified DBC as a potent immunosuppressive agent similar to the well-studied immunotoxicant 7,12-dimethylbenz[a]anthracene (DMBA). DBC, like DMBA, is bioactivated by cytochrome P450 (CYP) 1B1 and forms the reactive metabolite DBC-11,12-diol-13,14-epoxide (DBCDE). DBCDE is largely responsible for the genotoxicity associated with DBC exposure. The immunosuppressive properties of several PAHs are also linked to genotoxic mechanisms. Therefore, this study was designed to identify DBCDE-DNA adduct formation in the spleen and thymus of wild-type and cytochrome P450 1b1 (Cyp1b1) knockout (KO) mice using a highly sensitive stable-isotope dilution UHPLC-MS/MS method. Stable-isotope dilution UHPLC-MS/MS identified the major DBC adducts (±)-anti-cis-DBCDE-dA and (±)-anti-trans-DBCDE-dA in the lung, liver, and spleen of both WT and Cyp1b1 KO mice. However, adduct formation in the thymus was below the level of quantitation for our method. Additionally, adduct formation in Cyp1b1 KO mice was significantly reduced compared to wild-type (WT) mice receiving DBC via oral gavage. In conclusion, the current study identifies for the first time DBCDE-dA adducts in the spleen of mice supporting the link between genotoxicity and immunosuppression, in addition to supporting previous studies identifying Cyp1b1 as the primary CYP involved in DBC bioactivation to DBCDE. The high levels of DBC-DNA adducts identified in the spleen, along with the known high levels of Cyp1b1 expression in this organ, supports further investigation into DBC-mediated immunotoxicity. PMID:25868132

  14. S-(3-Aminobenzanthron-2-yl)cysteine in the globin of rats as a novel type of adduct and possible biomarker of exposure to 3-nitrobenzanthrone, a potent environmental carcinogen.

    PubMed

    Linhart, Igor; Hanzlíková, Iveta; Mráz, Jaroslav; Dušková, Šárka

    2017-03-10

    3-Nitrobenzanthrone (3-NBA), a potent environmental mutagen and carcinogen, is known to be activated in vivo to 3-benzanthronylnitrenium ion which forms both NH and C2-bound adducts with DNA and also reacts with glutathione giving rise to urinary 3-aminobenzanthron-2-ylmercapturic acid. In this study, acid hydrolysate of globin from rats dosed intraperitoneally with 3-NBA was analysed by HPLC/MS to identify a novel type of cysteine adduct, 3-aminobenzanthron-2-ylcysteine (3-ABA-Cys), confirmed using a synthesised standard. The 3-ABA-Cys levels in globin peaked after single 3-NBA doses of 1 and 2 mg/kg on day 2 to attain 0.25 and 0.49 nmol/g globin, respectively, thereafter declining slowly to 70-80% of their maximum values during 15 days. After dosing rats for three consecutive days with 1 mg 3-NBA/kg a significant cumulation of 3-ABA-Cys in globin was observed. 3-ABA-Cys was also found in the plasma hydrolysate. Herein, after dosing with 1 and 2 mg 3-NBA/kg the adduct levels peaked on day 1 at 0.15 and 0.51 nmol/ml plasma, respectively, thereafter declining rapidly to undetectable levels on day 15. In addition, sulphinamide adducts were also found in the exposed rats, measured indirectly as 3-aminobenzanthrone (3-ABA) split off from globin by mild acid hydrolysis. Levels of both types of adducts in the globin samples parallelled very well with 3-ABA/3-ABA-Cys ratio being around 1:8. In conclusion, 3-ABA-Cys is the first example of arylnitrenium-cysteine adduct in globin representing a new promising class of biomarkers to assess cumulative exposures to aromatic amines, nitroaromatics and heteroaromatic amines.

  15. Electronic Structure Principles and Aromaticity

    ERIC Educational Resources Information Center

    Chattaraj, P. K.; Sarkar, U.; Roy, D. R.

    2007-01-01

    The relationship between aromaticity and stability in molecules on the basis of quantities such as hardness and electrophilicity is explored. The findings reveal that aromatic molecules are less energetic, harder, less polarizable, and less electrophilic as compared to antiaromatic molecules, as expected from the electronic structure principles.

  16. Electronic Structure Principles and Aromaticity

    ERIC Educational Resources Information Center

    Chattaraj, P. K.; Sarkar, U.; Roy, D. R.

    2007-01-01

    The relationship between aromaticity and stability in molecules on the basis of quantities such as hardness and electrophilicity is explored. The findings reveal that aromatic molecules are less energetic, harder, less polarizable, and less electrophilic as compared to antiaromatic molecules, as expected from the electronic structure principles.

  17. Bacterial Degradation of Aromatic Compounds

    PubMed Central

    Seo, Jong-Su; Keum, Young-Soo; Li, Qing X.

    2009-01-01

    Aromatic compounds are among the most prevalent and persistent pollutants in the environment. Petroleum-contaminated soil and sediment commonly contain a mixture of polycyclic aromatic hydrocarbons (PAHs) and heterocyclic aromatics. Aromatics derived from industrial activities often have functional groups such as alkyls, halogens and nitro groups. Biodegradation is a major mechanism of removal of organic pollutants from a contaminated site. This review focuses on bacterial degradation pathways of selected aromatic compounds. Catabolic pathways of naphthalene, fluorene, phenanthrene, fluoranthene, pyrene, and benzo[a]pyrene are described in detail. Bacterial catabolism of the heterocycles dibenzofuran, carbazole, dibenzothiophene, and dibenzodioxin is discussed. Bacterial catabolism of alkylated PAHs is summarized, followed by a brief discussion of proteomics and metabolomics as powerful tools for elucidation of biodegradation mechanisms. PMID:19440284

  18. Hypervalent adducts of chalcogen-containing peri-substituted naphthalenes; reactions of sulfur, selenium, and tellurium with dihalogens.

    PubMed

    Knight, Fergus R; Fuller, Amy L; Bühl, Michael; Slawin, Alexandra M Z; Woollins, J Derek

    2010-08-16

    A range of structurally diverse compounds 1-15 {Nap[SPh](2).Br(4) (Nap = naphthalene-1,8-diyl); Nap[SePh][EPh].Br(4) (E = Se, S); Nap[SePh](2).I(2); Nap[SePh][EPh].3/2I(2) (E = Se, S); Nap[TePh][G].X(2) (G = SePh, SPh, Br, I; X = Br, I); and [Nap(PPh(2)OH)(SPh)](+)Br(3)(-)} formed from the reactions between peri-substituted naphthalene chalcogen donors D1-D8 {Nap[ER][E'R] (ER/E'R = SPh, SePh, TePh); Nap[TePh][X] (X = Br, I); and Nap[PPh(2)][SPh]} and dibromine and diiodine were characterized by X-ray crystallography and where possible by multinuclear NMR, IR, and MS. X-ray data for 1-15 were analyzed by naphthalene ring torsions, peri-atom displacement, splay angle magnitude, peri-distance, aromatic ring orientations, and quasi-linear three-body arrangements. The hypervalent linear moieties are considered in the context of the charge-transfer model and the 3c-4e model introduced by Pimentel and Rundle. In general, the conformation of the final products obeyed the rule based on charge-transfer that "seesaw" (X-ER(2)-X, 10-E-4) adducts arise when the halogen (X) is more electronegative than the chalcogen (E), and if the converse is true then, CT "spoke" (X-X-ER(2), 8-E-3) adducts are formed. Upon treatment with dibromine, selenium donor compounds D2 {Nap[SePh](2)} and D3 {Nap[SePh][SPh]} afford unusual tribromide salts of bromoselenyl cations containing a hypervalent X-E...E' 3c-4e type interaction. Upon treatment with diiodine, D2 and D3 form "Z-shaped", "extended spoke" adducts containing an uncommon 2:3 donor/chalcogen ratio and incorporating chains of I(2) held together by rare I...I interactions. As expected, "seesaw" 10-E-4 adducts are formed following the reaction of Te donors D4-D7 {Nap[TePh][X] (X = Br, I); Nap[TePh][EPh] (E = Se, S)} with the dihalogens. Naphthalene distortion in general is comparable between respective donor compounds and products 1-15. Ionic species 2 and 3 display a noticeable reduction in molecular distortion explained by the relief of

  19. Detection of Adriamycin-DNA adducts by accelerator mass spectrometry at clinically relevant Adriamycin concentrations.

    PubMed

    Coldwell, Kate E; Cutts, Suzanne M; Ognibene, Ted J; Henderson, Paul T; Phillips, Don R

    2008-09-01

    Limited sensitivity of existing assays has prevented investigation of whether Adriamycin-DNA adducts are involved in the anti-tumour potential of Adriamycin. Previous detection has achieved a sensitivity of a few Adriamycin-DNA adducts/10(4) bp DNA, but has required the use of supra-clinical drug concentrations. This work sought to measure Adriamycin-DNA adducts at sub-micromolar doses using accelerator mass spectrometry (AMS), a technique with origins in geochemistry for radiocarbon dating. We have used conditions previously validated (by less sensitive decay counting) to extract [(14)C]Adriamycin-DNA adducts from cells and adapted the methodology to AMS detection. Here we show the first direct evidence of Adriamycin-DNA adducts at clinically-relevant Adriamycin concentrations. [(14)C]Adriamycin treatment (25 nM) resulted in 4.4 +/- 1.0 adducts/10(7) bp ( approximately 1300 adducts/cell) in MCF-7 breast cancer cells, representing the best sensitivity and precision reported to date for the covalent binding of Adriamycin to DNA. The exceedingly sensitive nature of AMS has enabled over three orders of magnitude increased sensitivity of Adriamycin-DNA adduct detection and revealed adduct formation within an hour of drug treatment. This method has been shown to be highly reproducible for the measurement of Adriamycin-DNA adducts in tumour cells in culture and can now be applied to the detection of these adducts in human tissues.

  20. [Methodology of capillary electrophoresis-laser induced fluorescence immunoassay for highly sensitive detection of DNA adducts].

    PubMed

    Wang, Hailin; Zhang, Dapeng; Wang, Zhixin; Li, Tao; Feng, Feng; Wang, Chao; Gao, Haiyan

    2009-09-01

    DNA adducts is a very important class of biomarkers of human exposure to carcinogen, cancer risk assessment, and population susceptibility. There is a lack of a technology with a sufficient sensitivity to detect trace DNA adducts related to low environmental exposure levels. We attempt to develop a highly sensitive assay for the detection of DNA adducts by combining capillary electrophoresis-laser induced fluorescence (CE-LIF) with immunochemical recognition, or CE-LIF immunoassay. This review describes the recent research progress on CE-LIF instrument construction and the methodology of CE-LIF immunoassay for the detection of DNA adducts. The methodology study mainly involves the synthesis and characterization of the adduct containing DNA fluorescent probes, the interaction of DNA adducts and antibody, stabilization of trace DNA adducts-antibody complexes, and DNA-driven focusing.

  1. Benzo[b]fluoranthene: tumorigenicity in strain A/J mouse lungs, DNA adducts and mutations in the Ki-ras oncogene.

    PubMed

    Mass, M J; Abu-Shakra, A; Roop, B C; Nelson, G; Galati, A J; Stoner, G D; Nesnow, S; Ross, J A

    1996-08-01

    The polycyclic aromatic hydrocarbon benzo[b]fluoranthene (B[b]F) is a pervasive constituent of environmental combustion products. We sought to examine the lung tumorigenic activity of B[b]F in strain A/J mice, to study the relationship between formation and decay of B[b]F-DNA adducts and to examine mutations in the Ki-ras proto-oncogene in DNA from B[b]F-induced tumors. Mice were given i.p. injections of 0, 10, 50, 100 or 200 mg/kg body wt and lung adenomas were scored after 8 months. B[b]F induced significant numbers of mouse lung adenomas in a dose-related fashion, with the highest dose (200 mg/kg) yielding 6.95 adenomas/ mouse, with 100% of the mice exhibiting an adenoma. In mice given tricaprylin, the vehicle control, there were 0.60 adenomas/mouse, with 55% of the mice exhibiting an adenoma. Based on dose, B[b]F was less active than benzo[a]pyrene. DNA adducts were analyzed qualitatively and quantitatively by 32P-post-labeling in lungs of strain A/J mice 1, 3, 5, 7, 14 and 21 days after i.p. injection. Maximal levels of adduction occurred 5 days after treatment with the 200 mg/kg dose group, producing 1230 amol B[b]F-DNA adducts/microgram DNA. The major B[b]F-DNA adduct was identified by co-chromatography as trans-9, 10-dihydroxy-anti-11, 12-epoxy-5-hydroxy-9, 10, 11, 12-tetra-hydro-B[b]F-deoxyguanosine. Approximately 86% of the tumors had a mutation in codon 12 of the Ki-ras oncogene, as determined by direct DNA sequencing of PCR-amplified exon 1 and single-stranded conformation polymorphism analysis. Analysis of the Ki-ras mutation spectrum in 25 of 29 B[b]F-induced tumors revealed the predominant mutation to be a G-->T transversion in the first or second base of codon 12, congruous with the DNA adduct data. Our data are consistent with previous reports in mouse skin implicating a phenolic diol epoxide as the proximate carcinogenic form of B[b]F that binds to guanine.

  2. Heat shock protein 90 inhibitors suppress aryl hydrocarbon receptor-mediated activation of CYP1A1 and CYP1B1 transcription and DNA adduct formation.

    PubMed

    Hughes, Duncan; Guttenplan, Joseph B; Marcus, Craig B; Subbaramaiah, Kotha; Dannenberg, Andrew J

    2008-11-01

    The aryl hydrocarbon receptor (AhR), a client protein of heat shock protein 90 (HSP90), plays a significant role in polycyclic aromatic hydrocarbon (PAH)-induced carcinogenesis. Tobacco smoke, a source of PAHs, activates the AhR, leading to enhanced transcription of CYP1A1 and CYP1B1, which encode proteins that convert PAHs to genotoxic metabolites. The main objectives of this study were to determine whether HSP90 inhibitors suppress PAH-mediated induction of CYP1A1 and CYP1B1 or block benzo(a)pyrene [B(a)P]-induced formation of DNA adducts. Treatment of cell lines derived from oral leukoplakia (MSK-Leuk1) or esophageal squamous cell carcinoma (KYSE450) with a saline extract of tobacco smoke, B(a)P, or dioxin induced CYP1A1 and CYP1B1 transcription, resulting in enhanced levels of message and protein. Inhibitors of HSP90 [17-allylamino-17-demethoxygeldanamycin (17-AAG); celastrol] suppressed these inductive effects of PAHs. Treatment with 17-AAG and celastrol also caused a rapid and marked decrease in amounts of AhR protein without modulating levels of HSP90. The formation of B(a)P-induced DNA adducts in MSK-Leuk1 cells was inhibited by 17-AAG, celastrol, and alpha-naphthoflavone, a known AhR antagonist. The reduction in B(a)P-induced DNA adducts was due, at least in part, to reduced metabolic activation of B(a)P. Collectively, these results suggest that 17-AAG and celastrol, inhibitors of HSP90, suppress the activation of AhR-dependent gene expression, leading, in turn, to reduced formation of B(a)P-induced DNA adducts. Inhibitors of HSP90 may have a role in chemoprevention in addition to cancer therapy.

  3. Detection of 2-amino-1-methyl-6-phenylimidazo [4,5-b]-pyridine (PhIP)-DNA adducts in human pancreatic tissues

    PubMed Central

    ZHU, JIJIANG; RASHID, ASIF; CLEARY, KAREN; ABBRUZZESE, JAMES L.; FRIESS, HELMUT; TAKAHASHI, SATORU; SHIRAI, TOMOYUKI; LI, DONGHUI

    2008-01-01

    Recent epidemiologic investigations have observed an association between consumption of grilled or barbequed meat and an increased risk for pancreatic cancer, suggesting that dietary exposure to heterocyclic aromatic amines (HCA) may contribute to the development of this disease. 2-Amino-1-methyl-6-phenylimidazo [4,5-b]-pyridine (PhIP) is the most abundant HCA found in well-done and grilled meats. To determine whether HCA-induced DNA damage is present in the human pancreas, we used immunohistochemistry and computer-assisted image analysis to measure PhIP-DNA adducts in 54 normal pancreatic tissues (N) from persons without pancreatic cancer and in 38 normal adjacent pancreatic tissues (A), and 39 cancer tissues (T) from 68 patients with pancreatic adenocarcinoma. PhIP-DNA adducts were detected in 53 N, 34 A, and 39 T samples. Mean values (±SD) of the absorbency for PhIP staining were 0.22 ± 0.04, 0.24 ± 0.04, and 0.24 ± 0.03 for N, A, and T samples, respectively (p = 0.004). Using the median absorbency (0.21) of the samples from normal controls as the cut-off, 71% of A and 77% of T tissues, compared with 48% of N tissues, were distributed in the higher range (p = 0.009). The odds ratio of pancreatic cancer was 3.4 (95% confidence interval 1.5 to 7.5, p = 0.002) for individuals with a higher level of PhIP-DNA adducts. This is the first report of detection of PhIP-DNA adducts in human pancreatic tissue samples obtained from patients having unknown exposure to HCA. Although limited by the small sample size, these preliminary results suggest that PhIP exposure may contribute to human pancreatic cancer development. PMID:16908439

  4. DNA adducts in skin biopsies and 1-hydroxypyrene in urine of psoriasis patients and healthy volunteers following treatment with coal tar.

    PubMed

    Roelofzen, J H J; van der Valk, P G M; Godschalk, R; Dettbarn, G; Seidel, A; Golsteijn, L; Anzion, R; Aben, K K H; van Schooten, F J; Kiemeney, L A L M; Scheepers, P T J

    2012-08-13

    Coal tar ointments (CTO) are frequently used in the treatment of psoriasis and eczema, but CTO contain carcinogenic polycyclic aromatic hydrocarbons (PAH). PAH are absorbed and metabolized in the skin. In psoriasis, the skin barrier is altered and therefore, absorption and metabolism of PAH may differ from healthy skin. In this study, levels of urinary 1-hydroxypyrene and PAH-DNA adducts in the skin were studied in psoriatic patients and healthy volunteers. Three punch biopsies were taken from the lower back of 10 male volunteers and from a psoriatic plaque in 10 male patients. A surface of 6.25 cm(2) was treated with CTO. After 96 h CTO was removed and another three skin biopsies were collected from the treated area. DNA was isolated from skin biopsies and urine was collected during and after the exposure period. After 24h, a twofold lower 1-hydroxypyrene urinary excretion was observed in patients compared to healthy volunteers and after 48 h, this difference reached statistical significance (p<0.05). Over 96 h the median level of the sum of PAH-DNA adducts, analyzed by (32)P-post-labeling, increased from 3.5 before CTO administration to 21.1 adducts per 10(8) nucleotides in volunteers, and from 1.0 to 3.6 adducts per 10(8) nucleotides in patients. At 96 h, PAH-DNA levels were higher in healthy volunteers than in patients (p<0.05). Biomarkers for uptake, bioavailability and bioactivation of PAH were lower in patients compared to volunteers. These data suggest a lower risk of carcinogenic effects of CTO in psoriatic skin compared to healthy skin. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  5. Elucidation of reaction scheme describing malondialdehyde-acetaldehyde-protein adduct formation.

    PubMed

    Tuma, D J; Kearley, M L; Thiele, G M; Worrall, S; Haver, A; Klassen, L W; Sorrell, M F

    2001-07-01

    Malondialdehyde and acetaldehyde react together with proteins and form hybrid protein conjugates designated as MAA adducts, which have been detected in livers of ethanol-fed animals. Our previous studies have shown that MAA adducts are comprised of two distinct products. One adduct is composed of two molecules of malondialdehyde and one molecule of acetaldehyde and was identified as the 4-methyl-1,4-dihydropyridine-3,5-dicarbaldehyde derivative of an amino group (MDHDC adduct). The other adduct is a 1:1 adduct of malondialdehyde and acetaldehyde and was identified as the 2-formyl-3-(alkylamino)butanal derivative of an amino group (FAAB adduct). In this study, information on the mechanism of MAA adduct formation was obtained, focusing on whether the FAAB adduct serves as a precursor for the MDHDC adduct. Upon the basis of chemical analysis and NMR spectroscopy, two initial reaction steps appear to be a prerequisite for MDHDC formation. One step involves the reaction of one molecule of malondialdehyde and one of acetaldehyde with an amino group of a protein to form the FAAB product, while the other step involves the generation of a malondialdehyde-enamine. It appears that generation of the MDHDC adduct requires the FAAB moiety to be transferred to the nitrogen of the MDA-enamine. For efficient reaction of FAAB with the enamine to take place, additional experiments indicated that these two intermediates likely must be in positions on the protein of close proximity to each other. Further studies showed that the incubation of liver proteins from ethanol-fed rats with MDA resulted in a marked generation of MDHDC adducts, indicating the presence of a pool of FAAB adducts in the liver of ethanol-fed animals. Overall, these findings show that MDHDC-protein adduct formation occurs via the reaction of the FAAB moiety with a malondialdehyde-enamine, and further suggest that a similar mechanism may be operative in vivo in the liver during prolonged ethanol consumption.

  6. Catalytic aromatization of methane.

    PubMed

    Spivey, James J; Hutchings, Graham

    2014-02-07

    Recent developments in natural gas production technology have led to lower prices for methane and renewed interest in converting methane to higher value products. Processes such as those based on syngas from methane reforming are being investigated. Another option is methane aromatization, which produces benzene and hydrogen: 6CH4(g) → C6H6(g) + 9H2(g) ΔG°(r) = +433 kJ mol(-1) ΔH°(r) = +531 kJ mol(-1). Thermodynamic calculations for this reaction show that benzene formation is insignificant below ∼600 °C, and that the formation of solid carbon [C(s)] is thermodynamically favored at temperatures above ∼300 °C. Benzene formation is insignificant at all temperatures up to 1000 °C when C(s) is included in the calculation of equilibrium composition. Interestingly, the thermodynamic limitation on benzene formation can be minimized by the addition of alkanes/alkenes to the methane feed. By far the most widely studied catalysts for this reaction are Mo/HZSM-5 and Mo/MCM-22. Benzene selectivities are generally between 60 and 80% at methane conversions of ∼10%, corresponding to net benzene yields of less than 10%. Major byproducts include lower molecular weight hydrocarbons and higher molecular weight substituted aromatics. However, carbon formation is inevitable, but the experimental findings show this can be kinetically limited by the use of H2 or oxidants in the feed, including CO2 or steam. A number of reactor configurations involving regeneration of the carbon-containing catalyst have been developed with the goal of minimizing the cost of regeneration of the catalyst once deactivated by carbon deposition. In this tutorial review we discuss the thermodynamics of this process, the catalysts used and the potential reactor configurations that can be applied.

  7. Interaction of aromatic alcohols, aldehydes and acids with α-hydroxyl-containing carbon-centered radicals: A steady state radiolysis study

    NASA Astrophysics Data System (ADS)

    Samovich, S. N.; Brinkevich, S. D.; Shadyro, O. I.

    2013-01-01

    Benzaldehyde and its derivatives efficaciously oxidize in aqueous solutions α-hydroxyl-containing carbon-centered radicals (α-HCR) of various structures, suppressing thereby the radical recombination and fragmentation reactions. The compounds containing cinnamic moieties are capable of adding α-hydroxyethyl radicals (α-HER) to the carbon-carbon double bonds conjugated with the aromatic system to form molecular products identifiable by mass spectrometry. On radiolysis of aqueous ethanol solutions, reduction of α-HER by aromatic alcohols and acids has been shown to proceed via formation of their adducts with hydrated electron species.

  8. Use of haemoglobin adducts in exposure monitoring and risk assessment.

    PubMed

    Boogaard, Peter J

    2002-10-05

    Many industrial bulk chemicals are oxiranes or alkenes that are easily metabolised to oxiranes in mammalian systems. Many oxiranes may react with DNA and are therefore mutagenic in vitro. Some oxiranes have been shown to be carcinogenic in rodents in vivo as well. Despite the very limited evidence of the carcinogenicity of oxiranes in humans, they should be considered potential human carcinogens. As a consequence, exposure to these compounds should be minimised and controlled. Twenty-five years ago, Ehrenberg and co-workers suggested that exposure to oxiranes might be determined through the measurement of the adducts they form with haemoglobin (Hb). Ten years later, a modification of the Edman degradation was developed at Stockholm University that allowed determination of adducts with the N-terminal valine of Hb by GC-MS. In our laboratory, this methodology was modified and adapted for analysis on an industrial scale. Since 1987, exposure of operators in our facilities to ethylene oxide (EO) has been routinely monitored by determination of N-(2-hydroxyethyl)valine in Hb. Biological monitoring programmes for propylene oxide (PO) and 1,3-butadiene (BD) were developed later. In this review, the methodology and its results are discussed as a tool in human risk assessment of industrial chemicals. Two major advantages of Hb adduct determinations in risk assessment are (1) the qualitative information on the structure of reactive intermediates that may be obtained through the mass spectrometry, which may provide insight in the molecular toxicology of compounds such as BD, and (2) the possibility of reliable determination of exposure over periods of several months with limited number of samples for compounds such as ethylene oxide (EO), propylene oxide (PO) and BD which form stable adducts with Hb. Since good correlations between the airborne concentrations of these chemicals with their respective adducts have been established, Hb adducts can also be used to quantitate

  9. Adducts of mitomycin C and DNA in EMT6 mouse mammary tumor cells: effects of hypoxia and dicumarol on adduct patterns.

    PubMed

    Bizanek, R; Chowdary, D; Arai, H; Kasai, M; Hughes, C S; Sartorelli, A C; Rockwell, S; Tomasz, M

    1993-11-01

    6-CH3-3H-Mitomycin C (MC) was used to identify MC-DNA adducts formed in EMT6 mouse mammary tumor cells. DNA was isolated from cells treated with 3H-MC. The DNA was enzymatically digested, and the digest was analyzed for 3H-labeled adducts by high performance liquid chromatography. All four major adducts previously isolated and characterized in cell-free systems were detected: two different monoadducts and two bisadducts forming DNA-interstrand and DNA-intrastrand cross-links, respectively. No MC-DNA adducts other than the DNA interstrand cross-link had been shown previously to be formed in living cells. A MC-deoxyguanosine adduct of unknown structure was also detected in DNA from EMT6 cells; this adduct was also formed with purified EMT6 DNA. High performance liquid chromatography analysis was further applied to study the relationship between DNA adducts and cytotoxicity. The number of adducts increased with the concentration of MC in both aerobic and hypoxic cells. At a constant drug level, more adducts were observed in cells treated under hypoxic conditions than in cells treated aerobically; at 2 microM MC, 4.8 x 10(-7) and 3.1 x 10(-7) adducts/nucleotide were observed under hypoxic and aerobic conditions, respectively. The increased adduct frequency under hypoxia correlates with the known increased cytotoxicity of MC to EMT6 cells under hypoxic conditions. In addition, a higher ratio of cross-linked adducts to monoadducts was observed in hypoxic cells. The high performance liquid chromatography techniques were also used to examine the effects of dicumarol (DIC) on adduct patterns in cells treated simultaneously with 3H-MC. The MC-DNA adduct frequencies in DIC-treated cells were increased 1.5-fold under hypoxia and decreased 1.6-fold under aerobic conditions from those observed without DIC. This finding correlates with the known DIC-induced increase and decrease in the cytotoxicity of MC in hypoxic and aerobic EMT6 cells, respectively. The monoadduct resulting

  10. Prenatal polycyclic aromatic hydrocarbon (PAH) exposure and child behavior at age 6-7 years.

    PubMed

    Perera, Frederica P; Tang, Deliang; Wang, Shuang; Vishnevetsky, Julia; Zhang, Bingzhi; Diaz, Diurka; Camann, David; Rauh, Virginia

    2012-06-01

    Airborne polycyclic aromatic hydrocarbons (PAH) are widespread urban air pollutants from fossil fuel burning and other combustion sources. We previously reported that a broad spectrum of combustion-related DNA adducts in cord blood was associated with attention problems at 6-7 years of age in the Columbia Center for Children's Environmental Health (CCCEH) longitudinal cohort study. We evaluated the relationship between behavioral problems and two different measures of prenatal exposure--both specific to PAH--in the same cohort. Children of nonsmoking African-American and Dominican women in New York City (NYC) were followed from in utero to 6-7 years. Prenatal PAH exposure was estimated by personal air monitoring of the mothers during pregnancy as well as by the measurement of DNA adducts specific to benzo[a]pyrene (BaP), a representative PAH, in maternal and cord blood. At 6-7 years of age, child behavior was assessed using the Child Behavior Checklist (CBCL) (n = 253). Generalized linear models were used to test the association between prenatal PAH exposure and behavioral outcomes. In multivariate analyses, high prenatal PAH exposure, whether characterized by personal air monitoring (greater than the median of 2.27 ng/m³) or maternal and cord adducts (detectable or higher), was positively associated with symptoms of Anxious/Depressed and Attention Problems (p ≤ 0.05). These results provide additional evidence that environmental levels of PAH encountered in NYC air can adversely affect child behavior.

  11. High-temperature reactions of C 60 with polycyclic aromatic hydrocarbons

    NASA Astrophysics Data System (ADS)

    Martin, Natalia M.; Luzan, Serhiy M.; Talyzin, Alexandr V.

    2010-02-01

    Fullerenes are proposed as a precursor for preparation of nanocarbon materials using controlled collapse of cage structure by high temperature reaction with polycyclic aromatic hydrocarbons. The chemical modification of C 60 by reaction with anthracene and coronene was studied over a broad temperature interval. The products of the reaction were characterized by X-ray diffraction, and Raman and IR spectroscopy. Mono- and multi-adducts of C 60 with anthracene were obtained in the temperature interval 290-400 °C. Above 400 °C the C 60 adducts are not stable and decompose back to C 60 and anthracene. No chemical adducts of C 60 with coronene were found below 500 °C. Above this temperature fullerite structure was found to expand reflecting interaction with coronene melt and vapor. The reactions of C 60 with anthracene and C 60 with coronene at temperatures above 650 °C resulted in fullerene cage collapse and formation of nanocarbons. These nanocarbons were found to store up to 0.45 wt% of hydrogen at ambient temperatures despite negligible surface area.

  12. Biomonitoring of polycyclic aromatic hydrocarbons from coke oven emissions and reproductive toxicity in nonsmoking workers.

    PubMed

    Jeng, Hueiwang Anna; Pan, Chih-Hong; Lin, Wen-Yi; Wu, Ming-Tsang; Taylor, Steven; Chang-Chien, Guo-Ping; Zhou, Guodong; Diawara, Norou

    2013-01-15

    The objective of the cross-sectional study was to assess whether exposure to polycyclic aromatic hydrocarbons (PAHs) from coke oven emissions contributed to alteration of semen quality and sperm DNA integrity in nonsmoking workers. Nonsmoking coke oven workers from a steel plant in Taiwan served as the exposure groups (topside-oven workers for the high exposure group and side-oven workers for the low exposure group), and administrators and security personnel in the plant served as the control. An exposure assessment was conducted to determine both particulate and gaseous phase of PAH levels and urinary 1-hydroxypyrene (1-OHP) levels. Semen quality was analyzed according to WHO guidelines. DNA fragmentation and bulky DNA adducts were measured to assess sperm DNA integrity. There was no significant difference in sperm concentrations, vitality, and DNA fragmentation between the exposed group and the control. The high exposure group experienced significantly lower percentages of normal morphology as compared with the control (p=0.0001). Bulky DNA adducts were detected in the exposed group that were significant higher than the control (p=0.04). Exposure to PAHs from coke-oven emissions could contribute to increased levels of bulky DNA adducts in sperm.

  13. Biocidal properties of metal oxide nanoparticles and their halogen adducts

    NASA Astrophysics Data System (ADS)

    Haggstrom, Johanna A.; Klabunde, Kenneth J.; Marchin, George L.

    2010-03-01

    Nanosized metal oxide halogen adducts possess high surface reactivities due to their unique surface morphologies. These adducts have been used as reactive materials against vegetative cells, such as Escherichia coli as well as bacterial endospores, including Bacillus subtilis and Bacillus anthracis (Δ Sterne strain). Here we report high biocidal activities against gram-positive bacteria, gram-negative bacteria, and endospores. The procedure consists of a membrane method. Transmission electron micrographs are used to compare nanoparticle-treated and untreated cells and spores. It is proposed that the abrasive character of the particles, the oxidative power of the halogens/interhalogens, and the electrostatic attraction between the metal oxides and the biological material are responsible for high biocidal activities. While some activity was demonstrated, bacterial endospores were more resistant to nanoparticle treatment than the vegetative bacteria.

  14. Proteomic analysis of adducted butyrylcholinesterase for biomonitoring organophosphorus exposures

    PubMed Central

    Marsillach, Judit; Hsieh, Edward J.; Richter, Rebecca J.; MacCoss, Michael J.; Furlong, Clement E.

    2014-01-01

    Organophosphorus (OP) compounds include a broad group of toxic chemicals such as insecticides, chemical warfare agents and antiwear agents. The liver cytochromes P450 bioactivate many OPs to potent inhibitors of serine hydrolases. Cholinesterases were the first OP targets discovered and are the most studied. They are used to monitor human exposures to OP compounds. However, the assay that is currently used has limitations. The mechanism of action of OP compounds is the inhibition of serine hydrolases by covalently modifying their active-site serine. After structural rearrangement, the complex OP inhibitor-enzyme is irreversible and will remain in circulation until the modified enzyme is degraded. Mass spectrometry is a sensitive technology for analyzing protein modifications, such as OP-adducted enzymes. These analyses also provide some information about the nature of the OP adduct. Our aim is to develop high-throughput protocols for monitoring OP exposures using mass spectrometry. PMID:23123252

  15. Colorless, Transparent, Aromatic Polyimide Films

    NASA Technical Reports Server (NTRS)

    St. Clair, A. K.; St. Clair, T. L.; Ezzell, K. S.; Ely, R. M.

    1986-01-01

    New process yields aromatic condensation polyimide films essentially colorless. Films between 90- and 100-percent transparent at visible wavelength of 500 nm. Optically transparent polyimide films made from variety of aromatic condensation polyimides. Range from very pale in color to colorless, compared to bright yellow color of conventional/ commercial aromatic polyimide film. Increased transparency achieved at no sacrifice in thermal stability, flexibility, toughness, or mechanical properties. These features extremely attractive as films or coating materials for aerospace applications or for any other applications where high optical transparency or thermal stability is required.

  16. Synthesis of aromatic secondary diamines

    NASA Technical Reports Server (NTRS)

    Wolfe, J. F.; Greenwood, T. D.; Kahley, R. A.

    1979-01-01

    A series of N-methyl substituted aromatic polyamides derived from the secondary aromatic diamines, 4,4'-bis(methylamino)diphenylmethane, 3,3'-bis(methylamino) diphenylmethane, 4,4'-bis(methylamino)benzophenone or 3,3'-bis(methylamino)benzophenone and isophthaloyl dichloride, terphthaloyl dichloride or 3,3'diphenylmethane dicarboxylic acid dichloride was prepared by high temperature solution polymerization in s-tetrachloroethane. Compared to analogous unsubstituted and partially N-methylated aromatic polyamides, the full N-methylated polyamides exhibited significantly lower glass transition temperatures, reduced crystallinity, improved thermal stability and good solubility in chlorinated solvents.

  17. Mechanistic relationships between hepatic genotoxicity and carcinogenicity in male B6C3F1 mice treated with polycyclic aromatic hydrocarbon mixtures

    PubMed Central

    Phillips, Tracie D.; Richardson, Molly; Lisa Cheng, Yi-Shing; He, Lingyu; McDonald, Thomas J.; Cizmas, Leslie H.; Safe, Stephen H.; Donnelly, Kirby C.; Wang, Fen; Moorthy, Bhagavatula; Zhou, Guo-Dong

    2014-01-01

    The genotoxicity of a complex mixture [neutral fraction (NF)] from a wood preserving waste and reconstituted mixture (RM) mimicking the NF with seven major polycyclic aromatic hydrocarbons (PAHs) and benzo(a)pyrene (BaP) was investigated by determining DNA adducts and tumor incidence in male B6C3F1 mice exposed to 3 different doses of the chemical mixtures. The peak values of DNA adducts were observed after 24 h and the highest levels of PAH-DNA adducts were exhibited in mice administered NF+BaP, and the highest tumor incidence and mortality were also observed in this group. DNA adduct levels after 1, 7, or 21 d were significantly correlated with animal mortality and incidence of total tumors including liver, lung, and forestomach. However, only hepatic DNA adducts after 7 d significantly correlated with liver tumor incidence. Most proteins involved in DNA repair including ATM, pATR, Chk1, pChk1, DNA PKcs, XRCC1, FANCD2, Ku80, Mre11 and Brca2 were significantly lower in liver tumor tissue compared to non-tumor tissue. Expression of proteins involved in apoptosis and cell cycle regulation were also significantly different in tumor vs non-tumor tissues and it is possible that PAH-induced changes in these gene products are important for tumor development and growth. PMID:24888377

  18. Regulation of Benzo[a]pyrene-Mediated DNA- and Glutathione-Adduct Formation by 2,3,7,8-Tetrachlorodibenzo-p-dioxin in Human Lung Cells

    PubMed Central

    2010-01-01

    Environmental carcinogens, such as polycyclic aromatic hydrocarbons (PAHs), require metabolic activation to DNA-reactive metabolites in order to exert their tumorigenic effects. Benzo[a]pyrene (B[a]P), a prototypic PAH, is metabolized by cytochrome P450 (P450) 1A1/1B1 and epoxide hydrolase to (−)-B[a]P-7,8-dihydro-7,8-diol (B[a]P-7,8-dihydrodiol). B[a]P-7,8-dihydrodiol then undergoes further P4501A1/1B1-mediated metabolism to the ultimate carcinogen, (+)-anti-7,8-dihydroxy-9,10-epoxy-7,8,9,10-tetrahydro-B[a]P (B[a]PDE), which forms DNA-adducts primarily with 2′-deoxyguanosine (dGuo) to form (+)-anti-trans-B[a]PDE-N2-dGuo (B[a]PDE-dGuo) in DNA. Pretreatment of cells with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is known to induce P4501A1/1B1 mRNA expression through the aryl hydrocarbon receptor (AhR) pathway. This causes increased B[a]PDE-dGuo formation in liver cells. In contrast, TCDD induction of H358 lung cells surprisingly caused a decrease in (−)-B[a]P-7,8-dihydrodiol-mediated (+)-B[a]PDE-dGuo adduct formation when compared with the non-TCDD-induced cells. Furthermore, treatment of the TCDD-induced cells with (±)-B[a]PDE also resulted in decreased (+)-B[a]PDE-dGuo adduct formation when compared with the non-TCDD-induced cells. These data suggested that it was a detoxification pathway that had been up-regulated rather than an activation pathway that had been down-regulated. LC-MS was used to analyze B[a]PDE-dGuo and B[a]PDE-GSH-adducts in H358 lung and HepG2 liver cells. There was a significant increase in the (−)-B[a]PDE-GSH-adduct with high enantiomeric excess after treatment of the TCDD-induced H358 cells with (±)-B[a]PDE when compared with the noninduced cells. This could explain why increased activation of (−)-B[a]P-7,8-dihydrodiol through TCDD up-regulation of P4501A1/1B1 did not lead to increased (+)-B[a]PDE-dGuo adducts in the H358 lung cells. In addition, TCDD did not induce B[a]PDE-GSH-adduct formation in HepG2 liver cells. (±)-B[a]PDE-GSH-adducts

  19. GSTM1 null genotype as a risk factor for anti-BPDE-DNA adduct formation in mononuclear white blood cells of coke-oven workers.

    PubMed

    Pavanello, Sofia; Siwinska, Ewa; Mielzynska, Danuta; Clonfero, Erminio

    2004-03-14

    The influence of the genetic deletion polymorphism of glutathione S-transferase micro 1 (GSTM1 *0/*0) on levels of anti (+/-)-r-7,t-8-dihydroxy-t-9,10-oxy-7,8,9,10-tetrahydrobenzo[a]pyrene (anti-BPDE-DNA) adduct in the peripheral blood lymphocyte plus monocyte fraction (LMF) of coke-oven workers was investigated. A total of 95 male Polish coke-oven workers (60% current smokers) from two different plants comprised the sample population. Polycyclic aromatic hydrocarbons (PAH) exposure was assessed by means of the individual post-shift urinary excretion of 1-pyrenol (mean +/- S.D.: 6.93 +/- 7.20 micromol/mol creatinine; 70% of the subjects exceeded the proposed biological exposure index (BEI) 2.28 micromol/mol creatinine). Anti-BPDE-DNA adduct levels were detected by high performance liquid chromatography (HPLC)/fluorescence analysis of the anti-BPDE tetrol I-1 released after acid hydrolysis of DNA samples. Genotypes were determined by polymerase chain reaction (PCR) on the genomic DNA of each subject. Coke-oven workers without active GSTM1 (GSTM1 *0/*0, 33%) had significantly higher adduct levels than those with active GSTM1 (GSTM1*1/*1 and *1/*0) (5.90 +/- 5.59 versus 3.25 +/- 2.01 adducts/10(8) bases, Mann-Whitney U-test, z = 2.53, P = 0.011), PAH exposure in the two subgroups being similar (7.06 +/- 6.83 versus 6.67 +/- 8.00 1-pyrenol micromol/mol creatinine). The highest number of GSTM1 null subjects (12/23, 39%) belonged to the quartile with the highest adduct levels (i.e., >4.67 adducts/10(8) nucleotides). That is, coke-oven workers with GSTM1 *0/*0 genotype had a significantly higher risk of having high adduct levels than individuals with active GSTM1 genotype (Fisher exact test P = 0.0355; odds ratio (OR) = 4.145, 95% CI 1.0-18.8). Multiple linear regression analysis showed that the increase in anti-BPDE-DNA adduct levels in LMF was significantly related to the high occupational exposure to PAHs (benzo[a]pyrene (BaP)) of coke-oven workers (t = 3.087, P < 0

  20. Finite Element Biomechanics of Optic Nerve Sheath Traction in Adduction.

    PubMed

    Shin, Andrew; Yoo, Lawrence; Park, Joseph; Demer, Joseph L

    2017-10-01

    Historical emphasis on increased intraocular pressure (IOP) in the pathogenesis of glaucoma has been challenged by the recognition that many patients lack abnormally elevated IOP. We employed finite element analysis (FEA) to infer contribution to optic neuropathy from tractional deformation of the optic nerve head (ONH) and lamina cribrosa (LC) by extraocular muscle (EOM) counterforce exerted when optic nerve (ON) redundancy becomes exhausted in adduction. We characterized assumed isotropic Young's modulus of fresh adult bovine ON, ON sheath, and peripapillary and peripheral sclera by tensile elongation in arbitrary orientations of five specimens of each tissue to failure under physiological temperature and humidity. Physical dimensions of the FEA were scaled to human histological and magnetic resonance imaging (MRI) data and used to predict stress and strain during adduction 6 deg beyond ON straightening at multiple levels of IOP. Young's modulus of ON sheath of 44.6 ± 5.6 MPa (standard error of mean) greatly exceeded that of ON at 5.2 ± 0.4 MPa, peripapillary sclera at 5.5 ± 0.8 MPa, and peripheral sclera at 14.0 ± 2.3 MPa. FEA indicated that adduction induced maximum stress and strain in the temporal ONH. In the temporal LC, the maximum stress was 180 kPa, and the maximum strain was ninefold larger than produced by IOP elevation to 45 mm Hg. The simulation suggests that ON sheath traction by adduction concentrates far greater mechanical stress and strain in the ONH region than does elevated IOP, supporting the novel concept that glaucomatous optic neuropathy may result at least partly from external traction on the ON, rather than exclusively on pressure on the ON exerted from within the eye.

  1. Ion Pairs or Neutral Molecule Adducts? Cooperativity in Hydrogen Bonding

    ERIC Educational Resources Information Center

    DeKock, Roger L.; Schipper, Laura A.; Dykhouse, Stephanie C.; Heeringa, Lee P.; Brandsen, Benjamin M.

    2009-01-01

    We performed theoretical studies on the systems NH[subscript 3] times HF times mH[subscript 2]O, NH[subscript 3] times HCl times mH[subscript 2]O, with m = 0, 1, 2, and 6. The molecules with m = 0 form hydrogen-bonded adducts with little tendency to form an ion-pair structure. The molecule NH[subscript 3] times HCl times H[subscript 2]O cannot be…

  2. Ion Pairs or Neutral Molecule Adducts? Cooperativity in Hydrogen Bonding

    ERIC Educational Resources Information Center

    DeKock, Roger L.; Schipper, Laura A.; Dykhouse, Stephanie C.; Heeringa, Lee P.; Brandsen, Benjamin M.

    2009-01-01

    We performed theoretical studies on the systems NH[subscript 3] times HF times mH[subscript 2]O, NH[subscript 3] times HCl times mH[subscript 2]O, with m = 0, 1, 2, and 6. The molecules with m = 0 form hydrogen-bonded adducts with little tendency to form an ion-pair structure. The molecule NH[subscript 3] times HCl times H[subscript 2]O cannot be…

  3. Protein tyrosine adduct in humans self-poisoned by chlorpyrifos

    SciTech Connect

    Li, Bin; Eyer, Peter; Eddleston, Michael; Jiang, Wei; Schopfer, Lawrence M.; Lockridge, Oksana

    2013-06-15

    Studies of human cases of self-inflicted poisoning suggest that chlorpyrifos oxon reacts not only with acetylcholinesterase and butyrylcholinesterase but also with other blood proteins. A favored candidate is albumin because in vitro and animal studies have identified tyrosine 411 of albumin as a site covalently modified by organophosphorus poisons. Our goal was to test this proposal in humans by determining whether plasma from humans poisoned by chlorpyrifos has adducts on tyrosine. Plasma samples from 5 self-poisoned humans were drawn at various time intervals after ingestion of chlorpyrifos for a total of 34 samples. All 34 samples were analyzed for plasma levels of chlorpyrifos and chlorpyrifos oxon (CPO) as a function of time post-ingestion. Eleven samples were analyzed for the presence of diethoxyphosphorylated tyrosine by mass spectrometry. Six samples yielded diethoxyphosphorylated tyrosine in pronase digests. Blood collected as late as 5 days after chlorpyrifos ingestion was positive for CPO-tyrosine, consistent with the 20-day half-life of albumin. High plasma CPO levels did not predict detectable levels of CPO-tyrosine. CPO-tyrosine was identified in pralidoxime treated patients as well as in patients not treated with pralidoxime, indicating that pralidoxime does not reverse CPO binding to tyrosine in humans. Plasma butyrylcholinesterase was a more sensitive biomarker of exposure than adducts on tyrosine. In conclusion, chlorpyrifos oxon makes a stable covalent adduct on the tyrosine residue of blood proteins in humans who ingested chlorpyrifos. - Highlights: • Chlorpyrifos-poisoned patients have adducts on protein tyrosine. • Diethoxyphosphate-tyrosine does not lose an alkyl group. • Proteins in addition to AChE and BChE are modified by organophosphates.

  4. 2' and 3' Carboranyl uridines and their diethyl ether adducts

    DOEpatents

    Soloway, Albert H.; Barth, Rolf F.; Anisuzzaman, Abul K.; Alam, Fazlul; Tjarks, Werner

    1992-01-01

    There is disclosed a process for preparing carboranyl uridine nucleoside compounds and their diethyl ether adducts, which exhibit a tenfold increase in boron content over prior art boron containing nucleoside compounds. Said carboranyl uridine nucleoside compounds exhibit enhanced lipophilicity and hydrophilic properties adequate to enable solvation in aqueous media for subsequent incorporation of said compounds in methods for boron neutron capture therapy in mammalian tumor cells.

  5. In Vivo Effects of Ozone Exposure on Protein Adduct Formation by 1-Nitronaphthalene in Rat Lung

    PubMed Central

    Wheelock, Åsa M.; Boland, Bridget C.; Isbell, Margaret; Morin, Dexter; Wegesser, Teresa C.; Plopper, Charles G.; Buckpitt, Alan R.

    2005-01-01

    The incidence of serious photochemical smog events is steadily growing in urban environments around the world. The electrophilic metabolites of 1-nitronaphthalene (1-NN), a common air pollutant in urban areas, have been shown to bind covalently to proteins. 1-NN specifically targets the airway epithelium, and the toxicity is synergized by prior long-term ozone exposure in rat. In this study we investigated the formation of 1-NN protein adducts in the rat airway epithelium in vivo and examined how prior long-term ozone exposure affects adduct formation. Eight adducted proteins, several involved in cellular antioxidant defense, were identified. The extent of adduction of each protein was calculated, and two proteins, peroxiredoxin 6 and biliverdin reductase, were adducted at high specific activities (0.36–0.70 and 1.0 nmol adduct/nmol protein). Furthermore, the N-terminal region of calreticulin, known as vasostatin, was adducted only in ozone-exposed animals. Although vasostatin was adducted at relatively low specific activity (0.01 nmol adduct/nmol protein), the adduction only in ozone-exposed animals makes it a candidate protein for elucidating the synergistic toxicity between ozone and 1-NN. These studies identified in vivo protein targets for reactive 1-NN metabolites that are potentially associated with the mechanism of 1-NN toxicity and the synergistic effects of ozone. PMID:15845863

  6. In vivo effects of ozone exposure on protein adduct formation by 1-nitronaphthalene in rat lung.

    PubMed

    Wheelock, Asa M; Boland, Bridget C; Isbell, Margaret; Morin, Dexter; Wegesser, Teresa C; Plopper, Charles G; Buckpitt, Alan R

    2005-08-01

    The incidence of serious photochemical smog events is steadily growing in urban environments around the world. The electrophilic metabolites of 1-nitronaphthalene (1-NN), a common air pollutant in urban areas, have been shown to bind covalently to proteins. 1-NN specifically targets the airway epithelium, and the toxicity is synergized by prior long-term ozone exposure in rat. In this study we investigated the formation of 1-NN protein adducts in the rat airway epithelium in vivo and examined how prior long-term ozone exposure affects adduct formation. Eight adducted proteins, several involved in cellular antioxidant defense, were identified. The extent of adduction of each protein was calculated, and two proteins, peroxiredoxin 6 and biliverdin reductase, were adducted at high specific activities (0.36-0.70 and 1.0 nmol adduct/nmol protein). Furthermore, the N-terminal region of calreticulin, known as vasostatin, was adducted only in ozone-exposed animals. Although vasostatin was adducted at relatively low specific activity (0.01 nmol adduct/nmol protein), the adduction only in ozone-exposed animals makes it a candidate protein for elucidating the synergistic toxicity between ozone and 1-NN. These studies identified in vivo protein targets for reactive 1-NN metabolites that are potentially associated with the mechanism of 1-NN toxicity and the synergistic effects of ozone.

  7. Multiple DNA adducts in lymphocytes of smokers and nonsmokers determined by sup 32 P-postlabeling analysis

    SciTech Connect

    Jahnke, G.D.; Thompson, C.L.; Walker, M.P.; Gallagher, J.E.; Lucier, G.W.

    1990-01-01

    Identification of DNA adducts in peripheral lymphocytes could serve as a means of monitoring human exposure to potential genotoxic agents. In the study, DNA from peripheral lymphocytes of smokers and nonsmokers was examined for adducts by the P1 nuclease {sup 32}P-post-labeling technique. Thin layer chromatography (TLC) maps from both groups revealed multiple DNA adducts which ranged from no adducts for one individual to six adducts for a different individual. The total DNA adduct concentrations were approximately one adduct in 10 to the seventh-10 to the eighth power normal nucleotides. Comparison of the adduct TLC profiles revealed individual variation in both pattern and level of DNA adducts. The type and amount of adduct was not influenced by smoking history and remained unchanged in four out of six subjects who were resampled after a one month interval. One adduct detected in lymphocyte DNA co-migrated on TLC with an adduct derived by in vitro incubation of lymphocytes with benzo(a)pyrene (B(a)P). The 3H-nucloside values were consistent with values obtained by {sup 32}P-postlabeling of the same sample (correlation coefficient of 0.88). No relationship was apparent between the capacity of lymphocytes to form a (3H)-B(a)P-derived adduct in vitro and the concentration of the adduct, or total adducts present in untreated lymphocytes.

  8. Tunable degradation of maleimide-thiol adducts in reducing environments

    PubMed Central

    Baldwin, Aaron D.; Kiick, Kristi L.

    2011-01-01

    Addition chemistries are widely used in preparing biological conjugates, and in particular, maleimide-thiol adducts have been widely employed. Here we show that the resulting succinimide thioether formed by a Michael type addition of a thiol to N-ethylmaleimide (NEM), generally accepted as stable, can in fact undergo retro and exchange reactions in the presence of other thiol compounds at physiological pH and temperature, offering a novel strategy for controlled release. Model studies (1H NMR, HPLC) of NEM conjugated to 4-mercaptophenylacetic acid (MPA), N-acetylcysteine, or 3-mercaptopropionic acid (MP) incubated with glutathione showed half lives of conversion from 20–80 hrs, with extents of conversion from 20–90% for MPA and N-acetylcysteine conjugates. Ring-opened the resultant succinimide thioether as well as any MP adduct did not show retro and exchange reactions. The kinetics of the retro reactions can be modulated by the Michael donor’s reactivity; therefore the degradation of maleimide-thiol adducts could be tuned for controlled release of drugs or degradation of materials at timescales different than those currently possible via disulfide-mediated release. Such approaches may find a new niche for controlled release in reducing environments relevant in chemotherapy and sub-cellular trafficking. PMID:21863904

  9. Acetaldehyde and the genome: beyond nuclear DNA adducts and carcinogenesis.

    PubMed

    Brooks, Philip J; Zakhari, Samir

    2014-03-01

    The designation of acetaldehyde associated with the consumption of alcoholic beverages as "carcinogenic to humans" (Group 1) by the International Agency for Research on Cancer (IARC) has brought renewed attention to the biological effects of acetaldehyde, as the primary oxidative metabolite of alcohol. Therefore, the overall focus of this review is on acetaldehyde and its direct and indirect effects on the nuclear and mitochondrial genome. We first consider different acetaldehyde-DNA adducts, including a critical assessment of the evidence supporting a role for acetaldehyde-DNA adducts in alcohol related carcinogenesis, and consideration of additional data needed to make a conclusion. We also review recent data on the role of the Fanconi anemia DNA repair pathway in protecting against acetaldehyde genotoxicity and carcinogenicity, as well as teratogenicity. We also review evidence from the older literature that acetaldehyde may impact the genome indirectly, via the formation of adducts with proteins that are themselves critically involved in the maintenance of genetic and epigenetic stability. Finally, we note the lack of information regarding acetaldehyde effects on the mitochondrial genome, which is notable since aldehyde dehydrogenase 2 (ALDH2), the primary acetaldehyde metabolic enzyme, is located in the mitochondrion, and roughly 30% of East Asian individuals are deficient in ALDH2 activity due to a genetic variant in the ALDH2 gene. In summary, a comprehensive understanding of all of the mechanisms by which acetaldehyde impacts the function of the genome has implications not only for alcohol and cancer, but types of alcohol related pathologies as well.

  10. Malondialdehyde-acetaldehyde adducts decrease bronchial epithelial wound repair.

    PubMed

    Wyatt, Todd A; Kharbanda, Kusum K; Tuma, Dean J; Sisson, Joseph H; Spurzem, John R

    2005-05-01

    Most people who abuse alcohol are cigarette smokers. Previously, we have shown that malondialdehyde, an inflammation product of lipid peroxidation, and acetaldehyde, a component of both ethanol metabolism and cigarette smoke, form protein adducts that stimulate protein kinase C (PKC) activation in bronchial epithelial cells. We have also shown that PKC can regulate bronchial epithelial cell wound repair. We hypothesize that bovine serum albumin adducted with malondialdehyde and acetaldehyde (BSA-MAA) decreases bronchial epithelial cell wound repair via binding to scavenger receptors on bronchial epithelial cells. To test this, confluent monolayers of bovine bronchial epithelial cells were grown in serum-free media prior to wounding the cells. Bronchial epithelial cell wound closure was inhibited in a dose-dependent manner (up to 60%) in the presence of BSA-MAA than in media treated cells (Laboratory of Human Carcinogenesis [LHC]-9-Roswell Park Memorial Institute [RPMI]). The specific scavenger receptor ligand, fucoidan, also stimulated PKC activation and decreased wound repair. Pretreatment with fucoidan blocked malondialdehyde-acetaldehyde binding to bronchial epithelial cells. When bronchial epithelial cells were preincubated with a PKC alpha inhibitor, Gö 6976, the inhibition of wound closure by fucoidan and BSA-MAA was blocked. Western blot demonstrated the presence of several scavenger receptors on bronchial epithelial cell membranes, including SRA, SRBI, SRBII, and CD36. Scavenger receptor-mediated activation of PKC alpha may function to reduce wound healing under conditions of alcohol and cigarette smoke exposure where malondialdehyde-acetaldehyde adducts may be present.

  11. Thermal stability of DNA adducts induced by cyanomorpholinoadriamycin in vitro.

    PubMed Central

    Cullinane, C; Phillips, D R

    1993-01-01

    The Adriamycin derivative, cyanomorpholinoadriamycin (CMA) was reacted with DNA in vitro to form apparent interstrand crosslinks. The extent of interstrand crosslink formation was monitored by a gel electrophoresis assay and maximal crosslinking of DNA was observed within 1 hr with 5 microM of drug. The interstrand crosslinks were heat labile, with a midpoint melting temperature of 70 degrees C (10 min exposure to heat) in 45% formamide. When CMA-induced adducts were detected as blockages of lambda-exonuclease, 12 blockage sites were observed with 8 being prior to 5'-GG sequences, one prior to 5'-CC, one prior to 5'-GC and 2 at unresolved combinations of these sequences. These exonuclease-detected blockages reveal the same sites of CMA-induced crosslinking as detected by in vitro transcription footprinting and primer-extension blockages on single strand DNA, where the blockages at 5'-GG and 5'-CC were identified as sites of intrastrand crosslinking and the 5'-GC blockage as a probable site of interstrand crosslinking. The thermal stability of both types of crosslink (10 min exposure to heat) ranged from 63-70 degrees C at individual sites. High levels of adduct were detected with poly (dG-dC) but not with poly (dI-dC). These results suggest adduct formation involving an aminal linkage between the 3 position of the morpholino moiety and N2 of guanine. Images PMID:8493102

  12. Structural Characterization of Hydroxyl Radical Adducts in Aqueous Media

    NASA Astrophysics Data System (ADS)

    Janik, Ireneusz; Tripathi, G. N. R.

    2015-06-01

    The oxidation by the hydroxyl (OH) radical is one of the most widely studied reactions because of its central role in chemistry, biology, organic synthesis, and photocatalysis in aqueous environments, wastewater treatment, and numerous other chemical processes. Although the redox potential of OH is very high, direct electron transfer (ET) is rarely observed. If it happens, it mostly proceeds through the formation of elusive OH adduct intermediate which facilitates ET and formation of hydroxide anion. Using time resolved resonance Raman technique we structurally characterized variety of OH adducts to sulfur containing organic compounds, halide ions as well as some metal cations. The bond between oxygen of OH radical and the atom of oxidized molecule differs depending on the nature of solute that OH radical reacts with. For most of sulfur containing organics, as well as halide and pseudo-halide ions, our observation suggested that this bond has two-center three-electron character. For several metal aqua ions studied, the nature of the bond depends on type of the cation being oxidized. Discussion on spectral parameters of all studied hydroxyl radical adducts as well as the role solvent plays in their stabilization will be presented.

  13. Isolation of Cyclopropenylidene Lithium Adducts: The Weiss-Yoshida Reagent**

    PubMed Central

    Lavallo, Vincent; Ishida, Yutaka; Donnadieu, Bruno; Bertrand, Guy

    2008-01-01

    A lithium-halogen exchange reaction occurs when the chloro[bis(diisopropylamino)]cyclopropenium tetrafluoroborate salt 1 (X = BF4) is treated with n-butyllithium. The resulting cyclopropenylidene-lithium adduct 3 has been isolated in 45% yield. In the solid state, this compound exists as a polymeric chain with an overall stoichiometry of two LiBF4 per carbene ligand. Addition of 12-crown-4-ether does not liberate the carbene from the lithium cation, but affords a monomeric tertiary complex (60% yield) that includes the crown ether. Moreover, complex 3 can also be synthesized by depro tonation of the bis(diisopropylamino)cyclopropenium tetrafluoroborate salt 2 (X = BF4) with n-butyllithium, whereas using potassium bis(trimethylsilyl)amide the free cyclopropenylidene was isolated in 53% yield. These results as whole seem to demonstrate that only certain counteranions allow for the isolation of cyclopropenylidene-lithium adducts, and only bases not containing lithium allow for the isolation of the free cyclopropenylidene. The former and the latter presumably prevented Weiss and Yoshida from isolating what would have been the first example of a stable carbene-lithium adduct and a free carbene, respectively. PMID:16986195

  14. Detection and characterization of cyclic hydroxylamine adducts by mass spectrometry.

    PubMed

    Reis, Ana; Domingues, Maria R M; Amado, Francisco M L; Oliveira, M Manuel; Domingues, Pedro

    2008-05-01

    Two cyclic hydroxylamines (cHA) bearing pyrrolidine (CPH) and piperidine moieties (TMTH) were evaluated to trap hydroxyl, peptide and phospholipid free radicals using mass spectrometry for their detection. The cHA ionized as [M+H](+) ions, showing higher relative abundances when compared to the DMPO, probably due to higher ionization efficiency. In the presence of hydroxyl radicals, both cHA generated new ions that could be attributed to loss of (*)H and (*)CH(3), most likely deriving from decomposition reactions of the nitroxide spin adduct. Addition of cHA to Leucine-enkephalin and palmitoyl-lineloyl-glycerophosphatidylcholine free radicals promoted the formation of cHA biomolecule adducts, which were confirmed by MS/MS data. Results suggest that the cHA are not suitable for hydroxyl radical trapping but can be used for trapping biomolecule radicals, having the advantage, over the most used cyclic nitrones, of being water soluble. The biomolecule adducts identified by MS are ESR silent, evidencing the importance of MS detection.

  15. Protein tyrosine adduct in humans self-poisoned by chlorpyrifos

    PubMed Central

    Li, Bin; Eyer, Peter; Eddleston, Michael; Jiang, Wei; Schopfer, Lawrence M.; Lockridge, Oksana

    2013-01-01

    Studies of human cases of self-inflicted poisoning suggest that chlorpyrifos oxon reacts not only with acetylcholinesterase and butyrylcholinesterase but also with other blood proteins. A favored candidate is albumin because in vitro and animal studies have identified tyrosine 411 of albumin as a site covalently modified by organophosphorus poisons. Our goal was to test this proposal in humans by determining whether plasma from humans poisoned by chlorpyrifos has adducts on tyrosine. Plasma samples from 5 self-poisoned humans were drawn at various time intervals after ingestion of chlorpyrifos for a total of 34 samples. All 34 samples were analyzed for plasma levels of chlorpyrifos and chlorpyrifos oxon (CPO) as a function of time post-ingestion. Eleven samples were analyzed for the presence of diethoxyphosphorylated tyrosine by mass spectrometry. Six samples yielded diethoxyphosphorylated tyrosine in pronase digests. Blood collected as late as 5 days after chlorpyrifos ingestion was positive for CPO-tyrosine, consistent with the 20-day half-life of albumin. High plasma CPO levels did not predict detectable levels of CPO-tyrosine. CPO-tyrosine was identified in pralidoxime treated patients as well as in patients not treated with pralidoxime, indicating that pralidoxime does not reverse CPO binding to tyrosine in humans. Plasma butyrylcholinesterase was a more sensitive biomarker of exposure than adducts on tyrosine. In conclusion, chlorpyrifos oxon makes a stable covalent adduct on the tyrosine residue of blood proteins in humans who ingested chlorpyrifos. PMID:23566956

  16. Immunochemical detection of 4-hydroxynonenal protein adducts in oxidized hepatocytes.

    PubMed

    Uchida, K; Szweda, L I; Chae, H Z; Stadtman, E R

    1993-09-15

    We report here the development of an immunochemical procedure that uses an antibody specific to the 4-hydroxynonenal (HNE) moiety for the detection of HNE-protein adducts. The HNE-specific antibody was prepared by immunizing rabbits with a HNE-keyhole limpet hemocyanin conjugate and purifying the rabbit serum on an affinity gel prepared by covalent attachment of a HNE-conjugated heptapeptide. When various preparations of glyceraldehyde-3-phosphate dehydrogenase containing 0-7.0 equivalent of HNE-histidine residues per subunit were obtained by incubating samples of glyceraldehyde-3-phosphate dehydrogenase with increased amounts of HNE and subjected to immunoblotting with the HNE-specific antibody, the intensities of the blots were directly proportional to the number of HNE-histidine adducts as measured directly by amino acid analysis. Binding of the HNE-conjugated glyceraldehyde-3-phosphate dehydrogenase to the HNE-specific antibody could be completely inhibited by HNE-N-acetylhistidine, HNE-N-acetyllysine, or HNE-glutathione, suggesting that the antigenic determinant recognized by the antibody is the HNE moiety, not the HNE-amino acid conjugates, such as HNE-histidine, HNE-lysine, and HNE-cysteine. The utility of the HNE-specific antibody was demonstrated by its ability to react selectively with a number of HNE-protein adducts in immunoblot analyses of crude homogenates of rat liver hepatocytes that had been exposed to HNE or oxidative stresses with tert-butylhydroperoxide or metal-ion-catalyzed oxidation systems.

  17. Acetaminophen Adducts Detected in Serum of Pediatric Patients With Acute Liver Failure.

    PubMed

    Alonso, Estella M; James, Laura P; Zhang, Song; Squires, Robert H

    2015-07-01

    Previous studies in patients with acute liver failure identified acetaminophen (APAP) protein adducts in the serum of 12% and 19% of children and adults, respectively, with acute liver failure of indeterminate etiology. This article details the testing of APAP adducts in a subset (n = 393) of patients with varied diagnoses in the Pediatric Acute Liver Failure Study Group (PALFSG). Serum samples were available from 393 participants included in the PALFSG registry. Adduct measurement was performed using validated methods. Participants were grouped by diagnostic category as known APAP overdose, known other diagnosis, and indeterminate etiology. Demographic and clinical characteristics and participant outcomes were compared by adduct status (positive or negative) within each group. APAP adduct testing was positive in 86% of participants with known APAP overdose, 6% with other known diagnoses, and 11% with an indeterminate cause of liver failure. Adduct-positive participants were noted to have marked elevation of serum alanine aminotransferase and aspartate aminotransferase coupled with total serum bilirubin that was significantly lower than adduct-negative patients. In the indeterminate group, adduct-positive patients had different outcomes than adduct-negative patients (P = 0.03); spontaneous survival was 16 of 21 (76%) in adduct-positive patients versus 75 of 169 (44%) in adduct-negative patients. Prognosis did not vary by adduct status in patients with known diagnoses. Furthermore, study is needed to understand the relation of APAP exposure, as determined by the presence of APAP adducts, to the clinical phenotype and outcomes of children with acute liver failure.

  18. Hip adduction and abduction strength profiles in elite, sub-elite and amateur Australian footballers.

    PubMed

    Prendergast, Ned; Hopper, Diana; Finucane, Mark; Grisbrook, Tiffany L

    2016-09-01

    It has been reported that obtaining an adduction-to-abduction strength ratio of 90-100%, and an adduction strength equal to that of the uninjured side, are suitable clinical milestones for return to sport following groin injury. Little is known about hip adduction and abduction strength profiles in Australian footballers. This study aimed to compare isometric hip adduction and abduction strength profiles between preferred and non-preferred kicking legs in elite, sub-elite and amateur Australian footballers. Cross sectional study 36 elite, 19 sub-elite and 18 amateur Australian footballers, with a mean age of 24, 19 and 23 years respectively, were included. Maximal hip isometric adduction and abduction strength were measured using a hand held dynamometer with external belt fixation. There were no significant differences in isometric hip adduction (p=0.262) or abduction (p=0.934) strength, or the adduction-to-abduction ratio (p=0.163), between preferred and non-preferred kicking legs, regardless of playing level. Elite players had significantly greater isometric hip adduction and abduction strength than both sub-elite (mean difference; adduction=46.01N, p<0.001, abduction=30.79N, p=0.003) and amateur players (mean difference; adduction=78.72N, p<0.001, abduction=59.11N, p<0.001). There was no significant difference in the adduction-to-abduction ratio between the playing levels (p=0.165). No significant differences were found between preferred and non-preferred kicking legs across the playing levels for isometric hip adduction, abduction or the adduction-to-abduction ratio. This may have implications for developing groin injury prediction and return to sport criteria in Australian footballers. Copyright © 2015 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  19. Diels-Alder reactions of inert aromatic compounds within a self-assembled coordination cage.

    PubMed

    Horiuchi, Shinnosuke; Murase, Takashi; Fujita, Makoto

    2011-07-04

    A self-assembled coordination cage serves as a nanometer-sized molecular flask to promote the Diels-Alder reactions of aromatic hydrocarbons with N-cyclohexylmaleimide. The coordination cage accelerated the Diels-Alder reaction of anthracene at the electronically unfavorable, terminal benzene ring to give a compact, cavity-restrained syn-adduct. Activation-parameter measurements for the reactions revealed considerable reduction in the entropy cost, and preorganization of the substrates is a dominant factor in the enhanced reactivity. Owing to this entropy-cost reduction, otherwise-unreactive aromatic compounds, such as naphthalenes or triphenylene, also underwent Diels-Alder reactions in a regio- and stereocontrolled fashion. In the naphthalene Diels-Alder reaction, X-ray crystallographic analysis of the guest-inclusion complex clarified the reinforced orientation and proximity of the substrate pairs before the reaction. A perylene Diels-Alder adduct was stabilized inside the cage and protected from aerial oxidation. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Polybenzimidazoles via aromatic nucleophilic displacement

    NASA Technical Reports Server (NTRS)

    Connell, John W. (Inventor); Hergenrother, Paul M. (Inventor); Smith, Joseph G., Jr. (Inventor)

    1995-01-01

    Novel molecular weight controlled and endcapped polybenzimidazoles (PBI) are prepared by the aromatic nucleophilic displacement reaction of di(hydroxyphenyl benzimidazole) monomers with activated aromatic dihalides or activated aromatic dinitro compounds. The PBI are endcapped with mono(hydroxyphenyl) benzimidazoles. The polymerizations are carried out in polar aprotic solvents such as N-methyl-2-pyrrolidinone or N,N-dimethylacetamide using alkali metal bases such as potassium carbonate at elevated temperatures under nitrogen. Mono(hydroxyphenyl) benzimidazoles are synthesizedby reacting phenyl-4-hydroxybenzoate with aromatic (o-diamine)s in diphenylsulfone. Molecular weight controlled and endcapped PBI of new chemical structures are prepared that exhibit a favorable combination of physical and mechanical properties.

  1. Polybenzimidazoles Via Aromatic Nucleophilic Displacement

    NASA Technical Reports Server (NTRS)

    Connell, John W. (Inventor); Hergerrother, Paul M. (Inventor); Smith, Joseph G., Jr. (Inventor)

    1997-01-01

    Novel molecular weight controlled and endcapped polybenzimidazoles (PBI) are prepared by the aromatic nucleophilic displacement reaction of di(hydroxyphenylbenzimidazole) monomers with activated aromatic dihalides or activated aromatic dinitro compounds. The PBI are endcapped with mono(hydroxyphenyl)benzimidazoles. The polymerizations are carried out in polar aprotic solvents such as N-methyl-2-pyrrolidinone or N,N-dimethylacetamide using alkali metal bases such as potassium carbonate at elevated temperatures under nitrogen. Mono(hydroxyphenyl)benzimidazoles are synthesized by reacting phenyl-4-hydroxybenzoate with aromatic (o-diamine)s in diphenylsulfone. Molecular weight controlled and endcapped PBI of new chemical structures are prepared that exhibit a favorable combination of physical and mechanical properties.

  2. Three-dimensional aromatic networks.

    PubMed

    Toyota, Shinji; Iwanaga, Tetsuo

    2014-01-01

    Three-dimensional (3D) networks consisting of aromatic units and linkers are reviewed from various aspects. To understand principles for the construction of such compounds, we generalize the roles of building units, the synthetic approaches, and the classification of networks. As fundamental compounds, cyclophanes with large aromatic units and aromatic macrocycles with linear acetylene linkers are highlighted in terms of transannular interactions between aromatic units, conformational preference, and resolution of chiral derivatives. Polycyclic cage compounds are constructed from building units by linkages via covalent bonds, metal-coordination bonds, or hydrogen bonds. Large cage networks often include a wide range of guest species in their cavity to afford novel inclusion compounds. Topological isomers consisting of two or more macrocycles are formed by cyclization of preorganized species. Some complicated topological networks are constructed by self-assembly of simple building units.

  3. Description of aromaticity in porphyrinoids.

    PubMed

    Wu, Judy I; Fernández, Israel; Schleyer, Paul v R

    2013-01-09

    Like the larger nonplanar Möbius rings, porphyrinoid aromaticity is not due primarily to the macrocyclic π conjugation of the corresponding annulene perimeters. The block-localized wave function (BLW)-derived aromatic stabilization energies (ASE) of several porphyrinoids reveal that, on a per atom basis, the appended 6π electron heterocycles of porphyrinoids confer aromaticity much more effectively than the macrocyclic 4n+2 π electron conjugations. There is no direct relationship between thermochemical stability of porphyrinoids and their macrocyclic 4n or 4n+2 π electron counts. Porphyrinoids having an "antiaromatic" macrocyclic 4n+2 π electron conjugation pathway (e.g., 4) as well as those having no macrocyclic conjugation (e.g., 9) can be stabilized by aromaticity. Computed nucleus independent chemical shifts (NICS) and the anisotropy of the induced current density (ACID) disclose the intricate local versus macrocyclic circulation interplay for several porphyrinoids.

  4. Including the Copenhagen Adduction Exercise in the FIFA 11+ Provides Missing Eccentric Hip Adduction Strength Effect in Male Soccer Players: A Randomized Controlled Trial.

    PubMed

    Harøy, Joar; Thorborg, Kristian; Serner, Andreas; Bjørkheim, André; Rolstad, Linn E; Hölmich, Per; Bahr, Roald; Andersen, Thor Einar

    2017-08-01

    The FIFA 11+ was developed as a complete warm-up program to prevent injuries in soccer players. Although reduced hip adduction strength is associated with groin injuries, none of the exercises included in the FIFA 11+ seem to specifically target hip adduction strength. To investigate the effect on eccentric hip adduction strength of the FIFA 11+ warm-up program with or without the Copenhagen adduction exercise. Randomized controlled trial; Level of evidence, 1. We recruited 45 eligible players from 2 U19 elite male soccer teams. Players were randomized into 2 groups; 1 group carried out the standard FIFA 11+ program, while the other carried out the FIFA 11+ but replaced the Nordic hamstring exercise with the Copenhagen adduction exercise. Both groups performed the intervention 3 times weekly for 8 weeks. Players completed eccentric strength and sprint testing before and after the intervention. Per-protocol analyses were performed, and 12 players were excluded due to low compliance (<67% of sessions completed). The main outcome was eccentric hip adduction strength (N·m/kg). Between-group analyses revealed a significantly greater increase in eccentric hip adduction strength of 0.29 Nm/kg (8.9%; P = .01) in favor of the group performing the Copenhagen adduction exercise, whereas no within-group change was noted in the group that used the standard FIFA 11+ program (-0.02 N·m/kg [-0.7%]; P = .69). Including the Copenhagen adduction exercise in the FIFA 11+ program increases eccentric hip adduction strength, while the standard FIFA 11+ program does not. Registration: Registration: ISRCTN13731446 (International Standard Randomised Controlled Trial Number registry).

  5. Polyphenylquinoxalines via aromatic nucleophilic displacement

    NASA Technical Reports Server (NTRS)

    Hergenrother, Paul M. (Inventor); Connell, John W. (Inventor)

    1990-01-01

    Polyphenylquinoxalines are prepared by the nucleophilic displacement reaction of di(hydroxyphenyl)quinoxaline monomers with activated aromatic dihalides or dinitro compounds. The reactions are carried out in polar aprotic solvents using alkali metal bases at elevated temperatures under nitrogen. The di(hydroxyphenyl)quinoxaline monomers are prepared either by reacting stoichiometric quantities of aromatic bis(o-diamines) with a hydroxybenzil or by reacting o-phenylenediamine with a dihydroxybenzil or bis(hydroxyphenylglyoxylyl)benzene.

  6. Bioassay of polycyclic aromatic hydrocarbons

    SciTech Connect

    Van Kirk, E.A.

    1980-08-01

    A positive relationship was found between the photodynamic activity of 24 polycyclic aromatic hydrocarbons versus published results on the mutagenicity, carcinogenicity, and initiation of unscheduled DNA synthesis. Metabolic activation of benzo(a)pyrene resulted in detection of increased mutagenesis in Paramecium tetraurelia as found also in the Ames Salmonella assay. The utility of P. tetraurelia as a biological detector of hazardous polycyclic aromatic hydrocarbons is discussed.

  7. Polyphenylquinoxalines via aromatic nucleophilic displacement

    NASA Technical Reports Server (NTRS)

    Hergenrother, Paul M. (Inventor); Connell, John W. (Inventor)

    1991-01-01

    Polyphenylquinoxalines are prepared by the nucleophilic displacement reaction of di(hydroxyphenyl)quinoxaline monomers with activated aromatic dihalides or dinitro compounds. The reactions are carried out in polar aprotic solvents during alkali metal bases at elevated temperatures under nitrogen. The di(hydroxyphenyl)quinoxaline monomers are prepared either by reacting stoichiometric quantities of aromatic bis(o-diamines) with a hydroxybenzil or by reacting o-phenylenediamine with a dihydroxybenzil or bis(hydroxyphenylglyoxylyl)benzene.

  8. Comparison of biomarker and pathological responses in flounder (Platichthys flesus L.) induced by ingested polycyclic aromatic hydrocarbon (PAH) contamination.

    PubMed

    Reynolds, W J; Feist, S W; Jones, G J; Lyons, B P; Sheahan, D A; Stentiford, G D

    2003-08-01

    This study investigated the response of biomarker measurements and histopathological indicators of polycyclic aromatic hydrocarbon (PAH) exposure in the flounder (Platichthys flesus L.). Flounder were fed food spiked with a mixture of four PAHs at an environmentally relevant range of concentrations for either one or six months. Ethoxyresorufin-O-deethylase (EROD) activity was elevated following 1 month exposure to PAH concentrations up to 50 mgkg(-1) in food. Bile metabolite concentrations were found to increase with PAH concentration, up to 500 mgkg(-1) PAH. By comparison, no DNA adducts were detected and there were no significant histopathological changes observed. After 6 months exposure, EROD levels were not elevated but bile metabolites showed a similar dose dependent relationship as in the 1 month experiment, while DNA adducts were only detected in the highest PAH exposure groups. No significant histopathological changes were observed. The results are discussed with respect to the implications for the use of these methods in environmental monitoring studies.

  9. Polybenzoxazole via aromatic nucleophilic displacement

    NASA Technical Reports Server (NTRS)

    Hergenrother, Paul M. (Inventor); Connell, John W. (Inventor); Smith, Joseph G., Jr. (Inventor)

    1993-01-01

    Polybenzoxazoles (PBO) are heterocyclic macromolecules which were first synthesized in a two-step process by the initial formation of aromatic diacid chlorides with bis(o-aminophenol)s through solution condensation of aromatic diacid chlorides with bis(o-aminophenol)s followed by thermal cyclodehydration. Since then several methods were utilized in their synthesis. The most common synthetic method for PBO involves a polycondensation of bis(o-aminophenol)s with aromatic diacid diphenyl esters. Another preparative route involves the solution polycondensation of the hydrochloride salts of bis(o-amino phenol)s with aromatic diacids in polyphosphoric acid. Another synthetic method involves the initial formation of poly(o-hydroxy amide)s from silylated bis(o-aminophenol)s with aromatic diacid chlorides followed by thermal cyclodehydration to PBO. A recent preparative route involves the reaction of aromatic bisphenols with bis(fluorophenyl) benzoxazoles by the displacement reaction to form PBO. The novelty of the present invention is that high molecular weight PBO of new chemical structures are prepared that exhibit a favorable combination of physical and mechanical properties.

  10. Phase I and phase II reductive metabolism simulation of nitro aromatic xenobiotics with electrochemistry coupled with high resolution mass spectrometry.

    PubMed

    Bussy, Ugo; Chung-Davidson, Yu-Wen; Li, Ke; Li, Weiming

    2014-11-01

    Electrochemistry combined with (liquid chromatography) high resolution mass spectrometry was used to simulate the general reductive metabolism of three biologically important nitro aromatic molecules: 3-trifluoromethyl-4-nitrophenol (TFM), niclosamide, and nilutamide. TFM is a pesticide used in the Laurential Great Lakes while niclosamide and nilutamide are used in cancer therapy. At first, a flow-through electrochemical cell was directly connected to a high resolution mass spectrometer to evaluate the ability of electrochemistry to produce the main reduction metabolites of nitro aromatic, nitroso, hydroxylamine, and amine functional groups. Electrochemical experiments were then carried out at a constant potential of -2.5 V before analysis of the reduction products by LC-HRMS, which confirmed the presence of the nitroso, hydroxylamine, and amine species as well as dimers. Dimer identification illustrates the reactivity of the nitroso species with amine and hydroxylamine species. To investigate xenobiotic metabolism, the reactivity of nitroso species to biomolecules was also examined. Binding of the nitroso metabolite to glutathione was demonstrated by the observation of adducts by LC-ESI(+)-HRMS and the characteristics of their MSMS fragmentation. In conclusion, electrochemistry produces the main reductive metabolites of nitro aromatics and supports the observation of nitroso reactivity through dimer or glutathione adduct formation.

  11. Comparison of the toxicities of patulin and patulin adducts formed with cysteine.

    PubMed Central

    Lindroth, S; von Wright, A

    1978-01-01

    The toxicities of patulin and of the patulin adducts formed with cysteine were compared using the mutation-sensitive strain Escherichia coli W3110 thy polA1 and its polA1+ revertant. The acute toxicities of patulin and of the adduct mixture were also compared using NMRI mice. The adduct mixture was shown by thin-layer chromatography to consist of one ninhydrin-positive, one ninhydrin- and MBTH (3-methyl-2-benzothiazolinone hydrazone)-positive, three MBTH-positive, and two ninhydrin- and MBTH-negative components. The results showed that patulin was over 100 times more toxic to E. coli than the adduct complex. Neither patulin nor the adduct mixture was found to induce the repair effect in E. coli. In the mouse feeding tests, the oral 50% lethal dose for patulin was 29 mg/kg, while that of the adduct mixture was greater than 2,370 mg/kg. PMID:354524

  12. Hydrolytic Cleavage Products of Globin Adducts in Urine as Possible Biomarkers of Cumulative Dose: Proof of Concept Using Styrene Oxide as a Model Adduct-Forming Compound.

    PubMed

    Mráz, Jaroslav; Hanzlíková, Iveta; Moulisová, Alena; Dušková, Šárka; Hejl, Kamil; Bednářová, Aneta; Dabrowská, Ludmila; Linhart, Igor

    2016-04-18

    A new experimental model was designed to study the fate of globin adducts with styrene 7,8-oxide (SO), a metabolic intermediate of styrene and a model electrophilic compound. Rat erythrocytes were incubated with SO at 7 or 22 °C. Levels of specific amino acid adducts in globin were determined by LC/MS analysis of the globin hydrolysate, and erythrocytes with known adduct content were administered intravenously to recipient rats. The course of adduct elimination from the rat blood was measured over the following 50 days. In the erythrocytes incubated at 22 °C, a rapid decline in the adduct levels on the first day post-transfusion followed by a slow phase of elimination was observed. In contrast, the adduct elimination in erythrocytes incubated at 7 °C was nearly linear, copying elimination of intact erythrocytes. In the urine of recipient rats, regioisomeric SO adducts at cysteine, valine, lysine, and histidine in the form of amino acid adducts and/or their acetylated metabolites as well as SO-dipeptide adducts were identified by LC/MS supported by synthesized reference standards. S-(2-Hydroxy-1-phenylethyl)cysteine and S-(2-hydroxy-2-phenylethyl)cysteine, the most abundant globin adducts, were excreted predominantly in the form of the corresponding urinary mercapturic acids (HPEMAs). Massive elimination of HPEMAs via urine occurred within the first day from the erythrocytes incubated at both 7 and 22 °C. However, erythrocytes incubated at 7 °C also showed a slow second phase of elimination such that HPEMAs were detected in urine up to 50 days post-transfusion. These results indicate for the first time that globin adducts can be cleaved in vivo to modified amino acids and dipeptides. The cleavage products and/or their predictable metabolites are excreted in urine over the whole life span of erythrocytes. Some of the urinary adducts may represent a new type of noninvasive biomarker for exposure to adduct-forming chemicals.

  13. Optimizing proteolytic digestion conditions for the analysis of serum albumin adducts of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine, a potential human carcinogen formed in cooked meat.

    PubMed

    Peng, Lijuan; Turesky, Robert J

    2014-05-30

    Heterocyclic aromatic amines (HAAs) are carcinogens formed during the cooking of meats or arise in tobacco smoke. The genotoxic N-oxidized metabolites of HAAs bind to Cys residues of proteins to form arylsulfinamide adducts. However, these adducts are unstable and undergo hydrolysis during enzymatic digestion, and thus have been precluded as biomarkers of exposure to HAAs. Arylsulfinamide adducts of HAAs can undergo oxidation to form stable arylsulfonamide linkages, which are chemically stable and amenable for analysis. 2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) is a carcinogen present in cooked meat. We established a quantitative MS-based method to measure the sulfinamide adduct of PhIP formed at the cysteine(34) (Cys(34)) residue of human serum albumin (SA), following chemical oxidation of PhIP-modified SA with m-chloroperoxybenzoic acid. Different enzyme systems (trypsin; chymotrypsin; trypsin/chymotrypsin; proteinase K; pronase E; and pronase E/leucine aminopeptidase/prolidase) were evaluated for their proficiency of digestion of SA modified with PhIP. The strongest signal was observed for the L(31)QQC*PFEDHVK(41) peptide, by ultraperformance liquid chromatography and ion trap MS. A limit of quantification value was 0.3fmol of LQQC*PFEDHVK per μg SA, or 2.5 adducts per 10(5) SA molecules, when assaying 0.75μg of SA. This article describes a mass spectrometric based method to characterize and measure human serum albumin (SA) adducts of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), a carcinogenic heterocyclic aromatic amine formed in cooked meats and tobacco smoke. PhIP undergoes metabolic activation to form reactive N-oxidized intermediates that bind to DNA and proteins. N-oxidized PhIP metabolites bind to the Cys(34) residue of SA to form a sulfinamide linkage. However, the linkage undergoes hydrolysis during proteolysis, precluding the employment of this adduct as a biomarker in human studies. We have shown that the sulfinamide linkage

  14. Optimizing proteolytic digestion conditions for the analysis of serum albumin adducts of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine, a potential human carcinogen formed in cooked meat

    PubMed Central

    Peng, Lijuan; Turesky, Robert J.

    2014-01-01

    Heterocyclic aromatic amines (HAAs) are carcinogens formed during the cooking of meats or arise in tobacco smoke. The genotoxic N-oxidized metabolites of HAAs bind to Cys residues of proteins to form arylsulfinamide adducts. However, these adducts are unstable and undergo hydrolysis during enzymatic digestion, and thus have been precluded as biomarkers of exposure to HAAs. Arylsulfinamide adducts of HAAs can undergo oxidation to form stable arylsulfonamide linkages, which are chemically stable and amenable for analysis. 2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) is a carcinogen present in cooked meat. We established a quantitative MS-based method to measure the sulfinamide adduct of PhIP formed at the cysteine34 (Cys34) residue of human serum albumin (SA), following chemical oxidation of PhIP-modified SA with m-chloroperoxybenzoic acid. Different enzyme systems (trypsin; chymotrypsin; trypsin/chymotrypsin; proteinase K; pronase E; and pronase E/leucine aminopeptidase/prolidase) were evaluated for their proficiency of digestion of SA modified with PhIP. The strongest signal was observed for the L31QQC*PFEDHVK41 peptide, by ultraperformance liquid chromatography and ion trap MS. A limit of quantification value was 0.3 fmol of LQQC*PFEDHVK per μg SA, or 2.5 adducts per 105 SA molecules, when assaying 0.75 μg of SA. Biological significance This article describes a mass spectrometric based method to characterize and measure human serum albumin (SA) adducts of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), a carcinogenic heterocyclic aromatic amine formed in cooked meats and tobacco smoke. PhIP undergoes metabolic activation to form reactive N-oxidized intermediates that bind to DNA and proteins. N-oxidized PhIP metabolites bind to the Cys34 residue of SA to form a sulfinamide linkage. However, the linkage undergoes hydrolysis during proteolysis, precluding the employment of this adduct as a biomarker in human studies. We have shown that the

  15. Structure of adducts of isoindolo[2,1-a]benzimidazole derivatives with maleimides

    NASA Astrophysics Data System (ADS)

    Korolev, Oleksandr; Yegorova, Tatyana; Levkov, Igor; Malytskyy, Volodymyr; Shishkin, Oleg; Zubatyuk, Roman; Palamarchuk, Genadiy; Vedrenne, Marc; Baltas, Michel; Voitenko, Zoia

    2015-03-01

    The selectivity of formation and some mechanistic insights during the synthesis of substituted isoindolo[2,1-a]benzimidazoles are discussed. Furthermore, the reactions of the obtained products with maleimides were carried out. Two types rearrangement adducts together with intermediate Michael type adducts were isolated. The influence of the reaction conditions and reagents ratio is discussed. Specific spectral criteria for the identification of the Michael type adducts are indicated.

  16. Polycyclic Aromatic Hydrocarbons

    NASA Technical Reports Server (NTRS)

    Salama, Farid

    2010-01-01

    Carbonaceous materials play an important role in space. Polycyclic Aromatic Hydrocarbons (PAHs) are a ubiquitous component of the carbonaceous materials. PAHs are the best-known candidates to account for the IR emission bands. They are also thought to be among the carriers of the diffuse interstellar absorption bands (DIBs). PAH ionization states reflect the ionization balance of the medium while PAH size, composition, and structure reflect the energetic and chemical history of the medium. A major challenge is to reproduce in the laboratory the physical conditions that exist in the emission and absorption interstellar zones. The harsh physical conditions of the ISM -low temperature, collisionless, strong UV radiation fields- are simulated in the laboratory by associating a molecular beam with an ionizing discharge to generate a cold plasma expansion. PAH ions and radicals are formed from the neutral precursors in an isolated environment at low temperature and probed with high-sensitivity cavity ringdown spectroscopy in the NUV-NIR range. Carbon nanoparticles are also formed during the short residence time of the precursors in the plasma and are characterized with time-offlight mass spectrometry. These experiments provide unique information on the spectra of large carbonaceous molecules and ions in the gas phase that can now be directly compared to interstellar and circumstellar observations (IR emission bands, DIBs, extinction curve). These findings also hold great potential for understanding the formation process of interstellar carbonaceous grains. We will review recent progress in the experimental and theoretical studies of PAHs, compare the laboratory data with astronomical observations and discuss the global implications.

  17. Mitochondrial DNA Copy Number and Exposure to Polycyclic Aromatic Hydrocarbons

    PubMed Central

    Pavanello, Sofia; Dioni, Laura; Hoxha, Mirjam; Fedeli, Ugo; Mielzynska-Švach, Danuta; Baccarelli, Andrea A.

    2013-01-01

    Background Increased mitochondrial DNA copy number (mtDNAcn) is a biological response to mtDNA damage and dysfunction predictive of lung cancer risk. Polycyclic aromatic hydrocarbons (PAHs) are established lung carcinogens and may cause mitochondrial toxicity. Whether PAH exposure and PAH-related nuclear DNA (nDNA) genotoxic effects are linked with increased mtDNAcn has never been evaluated. Methods We investigated the effect of chronic exposure to PAHs on mtDNAcn in peripheral blood lymphocytes (PBLs) of 46 Polish male non-current smoking cokeoven workers and 44 matched controls, who were part of a group of 94 study individuals examined in our previous work. Subjects PAH exposure and genetic alterations were characterized through measures of internal dose (urinary 1-pyrenol), target dose [anti-benzo[a]pyrene diolepoxide (anti-BPDE)-DNA adduct], genetic instability (micronuclei, MN and telomere length [TL]) and DNA methylation [p53 promoter] in PBLs. mtDNAcn (MT/S) was measured using a validated real-time PCR method. Results Workers with PAH exposure above the median value (>3 µmol 1-pyrenol/mol creatinine) showed higher mtDNAcn [geometric means (GM) of 1.06 (unadjusted) and 1.07 (age-adjusted)] compared to controls [GM 0.89 (unadjusted); 0.89 (age-adjusted)] (p=0.029 and 0.016), as well as higher levels of genetic and chromosomal [i.e. anti-BPDE-DNA adducts (p<0.001), MN (p<0.001) and TL (p=0.053)] and epigenetic [i.e., p53 gene-specific promoter methylation (p<0.001)] alterations in the nDNA. In the whole study population, unadjusted and age-adjusted mtDNAcn was positively correlated with 1-pyrenol (p=0.043 and 0.032) and anti-BPDE-DNA adducts (p=0.046 and 0.049). Conclusions PAH exposure and PAH-related nDNA genotoxicity are associated with increased mtDNAcn. Impact The present study is suggestive of potential roles of mtDNAcn in PAH-induced carcinogenesis. PMID:23885040

  18. Correlation between Quadriceps Endurance and Adduction Moment in Medial Knee Osteoarthritis

    PubMed Central

    Ahn, Sung-Eun; Park, Min-Ji; Lee, Dae-Hee

    2015-01-01

    It is not clear whether the strength or endurance of thigh muscles (quadriceps and hamstring) is positively or negatively correlated with the adduction moment of osteoarthritic knees. This study therefore assessed the relationships between the strength and endurance of the quadriceps and hamstring muscles and adduction moment in osteoarthritic knees and evaluated predictors of the adduction moment. The study cohort comprised 35 patients with unilateral medial osteoarthritis and varus deformity who were candidates for open wedge osteotomy. The maximal torque (60°/sec) and total work (180°/sec) of the quadriceps and hamstring muscles and knee adduction moment were evaluated using an isokinetic testing device and gait analysis system. The total work of the quadriceps (r = 0.429, P = 0.037) and hamstring (r = 0.426, P = 0.045) muscles at 180°/sec each correlated with knee adduction moment. Preoperative varus deformity was positively correlated with adduction moment (r = 0.421, P = 0.041). Multiple linear regression analysis showed that quadriceps endurance at 180°/sec was the only factor independently associated with adduction moment (β = 0.790, P = 0.032). The adduction moment of osteoarthritic knees correlated with the endurance, but not the strength, of the quadriceps muscle. However, knee adduction moment did not correlate with the strength or endurance of the hamstring muscle. PMID:26539830

  19. Lifetimes and stabilities of familiar explosives molecular adduct complexes during ion mobility measurements

    PubMed Central

    McKenzie, Alan; DeBord, John Daniel; Ridgeway, Mark; Park, Melvin; Eiceman, Gary; Fernandez-Lima, Francisco

    2015-01-01

    Trapped ion mobility spectrometry coupled to mass spectrometry (TIMS-MS) was utilized for the separation and identification of familiar explosives in complex mixtures. For the first time, molecular adduct complex lifetimes, relative stability, binding energies and candidate structures are reported for familiar explosives. Experimental and theoretical results showed that the adduct size and reactivity, complex binding energy and the explosive structure tailors the stability of the molecular adduct complex. TIMS flexibility to adapt the mobility separation as a function of the molecular adduct complex stability (i.e., short or long IMS experiments / low or high IMS resolution) permits targeted measurements of explosives in complex mixtures with higher confidence levels. PMID:26153567

  20. Temporal and spatial features of the formation of DNA adducts in sulfur mustard-exposed skin

    SciTech Connect

    Batal, Mohamed; Boudry, Isabelle; Mouret, Stéphane; Wartelle, Julien; Emorine, Sandy; Bertoni, Marine; Bérard, Izabel; and others

    2013-12-15

    Sulfur mustard (SM) is a chemical warfare agent that targets skin where it induces large blisters. DNA alkylation is a critical step to explain SM-induced cutaneous symptoms. We determined the kinetics of formation of main SM–DNA adducts and compare it with the development of the SM-induced pathogenesis in skin. SKH-1 mice were exposed to 2, 6 and 60 mg/kg of SM and treated skin was biopsied between 6 h and 21 days. Formation of SM DNA adducts was dose-dependent with a maximum immediately after exposure. However, adducts were persistent and still detectable 21 days post-exposure. The time-dependent formation of DNA adducts was also found to be correlated with the appearance of apoptotic cells. This temporal correlation suggests that these two early events are responsible for the severity of the damage to the skin. Besides, SM–DNA adducts were also detected in areas located next to contaminated zone, thus suggesting that SM diffuses in skin. Altogether, this work provides for the first time a clear picture of SM-induced genotoxicity using DNA adducts as a marker. - Highlights: • Sulfur mustard adducts are formed in DNA after skin exposure. • DNA damage formation is an early event in the pathological process of skin burn. • The amount of SM–DNA adducts is maximal at the earliest time point investigated. • Adducts are still detected 3 weeks after exposure. • Sulfur mustard diffuses in skin especially when large doses are applied.

  1. Comparison of biological effects with albumin adducts of 4,4'-methylenediphenyl diisocyanate in workers.

    PubMed

    Sabbioni, Gabriele; Vanimireddy, Lakshiminiranjan Reddy; Lummus, Zana L; Bernstein, David I

    2017-04-01

    Lung sensitization and asthma are the main health effects of 4,4'-methylenediphenyl diisocyanate (MDI). Albumin adducts (isocyanate-specific adducts) of MDI might be involved in the etiology of sensitization reactions. Albumin adducts of MDI were analyzed in sera of diisocyanate-exposed worker with and without diisocyanate occupational asthma (DA), as well as in exposed workers with and without diisocyanate-specific IgG antibodies. In DA-positive workers and IgG-positive workers, albumin adducts were significantly higher versus workers without DA and those who were specific IgG negative. The odds ratio to be DA-positive was 57 times larger for workers with adduct levels above 230 fmol/mg. The odds ratio to be IgG-positive was 10 times larger for workers with adduct levels above 113 fmol/mg. Therefore, albumin adducts appear to be a good predictor of the biological effects. The albumin-adduct levels in workers without biological effects were in the range of the adduct levels found in previous studies of healthy MDI-factory and construction site workers.

  2. Regiochemically controlled synthesis of a β-4-β' [70]fullerene bis-adduct

    DOE PAGES

    Cerón, Maira R.; Castro, Edison; Neti, Venkata S. Pavan K.; ...

    2016-12-22

    A β-4-β' C70 bis-adduct regioisomer and an uncommon mono-adduct β-malonate C70 derivative were synthesized by using a Diels–Alder cycloaddition followed by an addition–elimination of bromo-ethylmalonate and a retro-Diels–Alder cycloaddition reaction. Here, we also report the regioselective synthesis and spectroscopic characterization of Cs-symmetric tris- and C2v-symmetric tetra-adducts of C70, which are the precursors of the mono- and bis-adduct final products.

  3. Regiochemically controlled synthesis of a β-4-β' [70]fullerene bis-adduct

    SciTech Connect

    Cerón, Maira R.; Castro, Edison; Neti, Venkata S. Pavan K.; Dunk, Paul W.; Echegoyen, Luis A.

    2016-12-22

    A β-4-β' C70 bis-adduct regioisomer and an uncommon mono-adduct β-malonate C70 derivative were synthesized by using a Diels–Alder cycloaddition followed by an addition–elimination of bromo-ethylmalonate and a retro-Diels–Alder cycloaddition reaction. Here, we also report the regioselective synthesis and spectroscopic characterization of Cs-symmetric tris- and C2v-symmetric tetra-adducts of C70, which are the precursors of the mono- and bis-adduct final products.

  4. Chlorambucil-adducts in DNA analyzed at the oligonucleotide level using HPLC-ESI MS.

    PubMed

    Mohamed, Dalia; Mowaka, Shereen; Thomale, Jürgen; Linscheid, Michael W

    2009-08-01

    Chlorambucil (N,N-bis(2-chloroethyl)-p-aminophenylbutyric acid) is a bifunctional alkylating drug belonging to the nitrogen mustard group and is widely used as an anticancer agent. As the antitumor activity of the nitrogen mustards is based on the formation of adducts with genomic DNA, calf thymus DNA-Chlorambucil adducts were the major target in this study. Calf thymus DNA was incubated with Chlorambucil to induce the formation of a wide variety of adducts. Subsequently, enzymatic digestion of the DNA was performed using Benzonase and Nuclease S1 aiming at the production of oligonucleotides. Separation and structure elucidation of the individual DNA-Chlorambucil adducts was achieved using HPLC interfaced to electrospray ionization ion trap mass spectrometry. Both trinucleotide and tetranucleotide Chlorambucil adducts were detected. The majority of the detected trinucleotide adducts involved monofunctional alkylation with guanine being the hotspot for alkylation. Only a few bifunctional trinucleotide adducts both intra- and interstrand cross-links were found. On the contrary, cross-linked adducts were the major detected tetranucleotides in which the intrastrand cross-links predominated over the interstrand cross-links. To a lesser extent, monofunctional guanine alkylated tetranucleotides were detected as well. With MS(n) experiments, the detailed structures of Chlorambucil adducts of the tri- and tetranucleotides were determined.

  5. Mass spectrometry for the assessment of the occurrence and biological consequences of DNA adducts

    PubMed Central

    Liu, Shuo; Wang, Yinsheng

    2016-01-01

    Exogenous and endogenous sources of chemical species can react, directly or after metabolic activation, with DNA to yield DNA adducts. If not repaired, DNA adducts may compromise cellular functions by blocking DNA replication and/or inducing mutations. Unambiguous identification of the structures and accurate measurements of the levels of DNA adducts in cellular and tissue DNA constitute the first and important step towards understanding the biological consequences of these adducts. The advances in mass spectrometry (MS) instrumentation in the past 2–3 decades have rendered MS an important tool for structure elucidation, quantification, and revelation of the biological consequences of DNA adducts. In this review, we summarized the development of MS techniques on these fronts for DNA adduct analysis. We placed our emphasis of discussion on sample preparation, the combination of MS with gas chromatography-or liquid chromatography (LC)-based separation techniques for the quantitative measurement of DNA adducts, and the use of LC-MS along with molecular biology tools for understanding the human health consequences of DNA adducts. The applications of mass spectrometry-based DNA adduct analysis for predicting the therapeutic outcome of anti-cancer agents, for monitoring the human exposure to endogenous and environmental genotoxic agents, and for DNA repair studies were also discussed. PMID:26204249

  6. Diallyl sulfide inhibits diethylstilbesterol-induced DNA adducts in the breast of female ACI rats.

    PubMed

    Green, M; Wilson, C; Newell, O; Sadrud-Din, S; Thomas, R

    2005-09-01

    Diethylstilbestrol (DES) is metabolized to reactive intermediates that produce DNA adducts and ultimately cancer. Diallyl sulfide (DAS) has been shown to inhibit the metabolism of several procarcinogens. The ability of DES to produce DNA adducts in microsomal, mitochondrial, and nuclear in vitro metabolic systems and in the breast of female ACI rats, as well as ability of DAS to inhibit DNA adducts were investigated. Microsomes, mitochondria, and nuclei isolated from breast tissue of female ACI rats were used to catalyze oxidation reactions. Female ACI rats were treated i.p. as follows: (1) corn oil, (2) 200mg/kg DES, (3) 200mg/kg DES/200mg/kg of DAS, (4) 200mg/kg DES/400mg/kg DAS. DES produced DNA adducts in each metabolic system. The relative adduct levels were 2.1 x 10(-4), 6.2 x 10(-6), and 2.9 x 10(-7) in microsomal, mitochondrial, and nuclear reactions, respectively. DAS inhibited DNA adducts in each metabolic system. The percent inhibition ranged from 86% in microsomes to 93% in nuclei. DES produced DNA adducts in mtDNA and nDNA. DAS completely inhibited the DES-induced mtDNA adducts and caused a dose dependent decrease in nDNA adduct formation. These findings suggest that DAS could inhibit DES-induced breast cancer by inhibiting its metabolism.

  7. Gas phase adduct reactions in MOCVD growth of GaN

    SciTech Connect

    Thon, A.; Kuech, T.F.

    1996-11-01

    Gas phase reactions between trimethylgallium (TMG) and ammonia were studied at high temperatures, characteristic to MOCVD of GaN reactors, by means of in situ mass spectroscopy in a flow tube reactor. It is shown, that a very fast adduct formation followed by elimination of methane occurs. The decomposition of TMG and the adduct-derived compounds are both first order and have similar apparent activation energy. The pre-exponential factor of the adduct decomposition is smaller, and hence is responsible for the higher full decomposition temperature of the adduct relative to that of TMG.

  8. Methylation of cytosine at C5 in a CpG sequence context causes a conformational switch of a benzo[a]pyrene diol epoxide-N2-guanine adduct in DNA from a minor groove alignment to intercalation with base displacement.

    SciTech Connect

    Zhang, N.; Lin, C.; Huang, X.; Kolbanovskiy, A.; Hingerty, Brian E; Amin, S.; Broyde, S.; Geactinov, N. E.; Patel, D. J.

    2005-03-01

    It is well known that CpG dinucleotide steps in DNA, which are highly methylated at the 5-position of cytosine (meC) in human tissues, exhibit a disproportionate number of mutations within certain codons of the p53 gene. There is ample published evidence indicating that the reactivity of guanine with anti-B[a]PDE (a metabolite of the environmental carcinogen benzo[a]pyrene) at CpG mutation hot spots is enhanced by the methylation of the cytosine residue flanking the target guanine residue on the 5'-side. In this work we demonstrate that such a methylation can also dramatically affect the conformational characteristics of an adduct derived from the reaction of one of the two enantiomers of anti-B[a]PDE with the exocyclic amino group of guanine ([BP]G adduct). A detailed NMR study indicates that the 10R (-)-trans-anti-[BP]G adduct undergoes a transition from a minor groove-binding alignment of the aromatic BP ring system in the unmethylated C-[BP]G sequence context, to an intercalative BP alignment with a concomitant displacement of the modified guanine residue into the minor groove in the methylated meC-[BP]G sequence context. By contrast, a minor groove-binding alignment was observed for the stereoisomeric 10S (+)-trans-anti-[BP]G adduct in both the C-[BP]G and meC-[BP]G sequence contexts. This remarkable conformational switch resulting from the presence of a single methyl group at the 5-position of the cytosine residue flanking the lesion on the 5'-side, is attributed to the hydrophobic effect of the methyl group that can stabilize intercalated adduct conformations in an adduct stereochemistry-dependent manner. Such conformational differences in methylated and unmethylated CpG sequences may be significant because of potential alterations in the cellular processing of the [BP]G adducts by DNA transcription, replication, and repair enzymes.

  9. Comparative DNA adduct formation and induction of colonic aberrant crypt foci in mice exposed to 2-amino-9H-pyrido[2,3-b]indole, 2-amino-3,4-dimethylimidazo[4,5-f]quinoline, and azoxymethane.

    PubMed

    Kim, Sangyub; Guo, Jingshu; O'Sullivan, M Gerald; Gallaher, Daniel D; Turesky, Robert J

    2016-03-01

    Considerable evidence suggests that environmental factors, including diet and cigarette smoke, are involved in the pathogenesis of colon cancer. Carcinogenic nitroso compounds (NOC), such as N-nitrosodimethylamine (NDMA), are present in tobacco and processed red meat, and NOC have been implicated in colon cancer. Azoxymethane (AOM), commonly used for experimental colon carcinogenesis, is an isomer of NDMA, and it produces the same DNA adducts as does NDMA. Heterocyclic aromatic amines (HAAs) formed during the combustion of tobacco and high-temperature cooking of meats are also associated with an elevated risk of colon cancer. The most abundant carcinogenic HAA formed in tobacco smoke is 2-amino-9H-pyrido[2,3-b]indole (AαC), whereas 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ) is the most potent carcinogenic HAA formed during the cooking of meat and fish. However, the comparative tumor-initiating potential of AαC, MeIQ, and AOM is unknown. In this report, we evaluate the formation of DNA adducts as a measure of genotoxicity, and the induction of colonic aberrant crypt foci (ACF) and dysplastic ACF, as an early measure of carcinogenic potency of these compounds in the colon of male A/J mice. Both AαC and AOM induced a greater number of DNA adducts than MeIQ in the liver and colon. AOM induced a greater number of ACF and dysplastic ACF than either AαC or MeIQ. Conversely, based on adduct levels, MeIQ-DNA adducts were more potent than AαC- and AOM-DNA adducts at inducing ACF. Long-term feeding studies are required to relate levels of DNA adducts, induction of ACF, and colon cancer by these colon genotoxicants. © 2016 Wiley Periodicals, Inc.

  10. Comparative DNA adduct formation and induction of colonic aberrant crypt foci in mice exposed to 2-amino-9H-pyrido[2,3-b]indole, 2-amino-3,4-dimethylimidazo[4,5-f]quinoline and azoxymethane

    PubMed Central

    Kim, Sangyub; Guo, Jingshu; O’Sullivan, M. Gerald; Gallaher, Daniel D.; Turesky, Robert J.

    2015-01-01

    Considerable evidence suggests that environmental factors, including diet and cigarette smoke, are involved in the pathogenesis of colon cancer. Carcinogenic nitroso compounds (NOC), such as N-nitrosodimethylamine (NDMA), are present in tobacco and processed red meat, and NOC have been implicated in colon cancer. Azoxymethane (AOM), commonly used for experimental colon carcinogenesis, is an isomer of NDMA, and it produces the same DNA adducts as does NDMA. Heterocyclic aromatic amines (HAAs) formed during the combustion of tobacco and high-temperature cooking of meats are also associated with an elevated risk of colon cancer. The most abundant carcinogenic HAA formed in tobacco smoke is 2-amino-9H-pyrido[2,3-b]indole (AαC), whereas 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ) is the most potent carcinogenic HAA formed during the cooking of meat and fish. However, the comparative tumor-initiating potential of AαC, MeIQ, and AOM is unknown. In this report, we evaluate the formation of DNA adducts as a measure of genotoxicity, and the induction of colonic aberrant crypt foci (ACF) and dysplastic ACF, as an early measure of carcinogenic potency of these compounds in the colon of male A/J mice. Both AαC and AOM induced a greater number of DNA adducts than MeIQ in the liver and colon. AOM induced a greater number of ACF and dysplastic ACF than either AαC or MeIQ. Conversely, based on adduct levels, MeIQ-DNA adducts were more potent than AαC- and AOM-DNA adducts at inducing ACF. Long-term feeding studies are required to relate levels of DNA adducts, induction of ACF, and colon cancer by these colon genotoxicants. PMID:26734915

  11. Structural and biochemical impact of C8-aryl-guanine adducts within the NarI recognition DNA sequence: influence of aryl ring size on targeted and semi-targeted mutagenicity

    PubMed Central

    Sproviero, Michael; Verwey, Anne M.R.; Rankin, Katherine M.; Witham, Aaron A.; Soldatov, Dmitriy V.; Manderville, Richard A.; Fekry, Mostafa I.; Sturla, Shana J.; Sharma, Purshotam; Wetmore, Stacey D.

    2014-01-01

    Chemical mutagens with an aromatic ring system may be enzymatically transformed to afford aryl radical species that preferentially react at the C8-site of 2′-deoxyguanosine (dG). The resulting carbon-linked C8-aryl-dG adduct possesses altered biophysical and genetic coding properties compared to the precursor nucleoside. Described herein are structural and in vitro mutagenicity studies of a series of fluorescent C8-aryl-dG analogues that differ in aryl ring size and are representative of authentic DNA adducts. These structural mimics have been inserted into a hotspot sequence for frameshift mutations, namely, the reiterated G3-position of the NarI sequence within 12mer (NarI(12)) and 22mer (NarI(22)) oligonucleotides. In the NarI(12) duplexes, the C8-aryl-dG adducts display a preference for adopting an anti-conformation opposite C, despite the strong syn preference of the free nucleoside. Using the NarI(22) sequence as a template for DNA synthesis in vitro, mutagenicity of the C8-aryl-dG adducts was assayed with representative high-fidelity replicative versus lesion bypass Y-family DNA polymerases, namely, Escherichia coli pol I Klenow fragment exo− (Kf−) and Sulfolobus solfataricus P2 DNA polymerase IV (Dpo4). Our experiments provide a basis for a model involving a two-base slippage and subsequent realignment process to relate the miscoding properties of C-linked C8-aryl-dG adducts with their chemical structures. PMID:25361967

  12. Bacterial degradation of monocyclic aromatic amines.

    PubMed

    Arora, Pankaj K

    2015-01-01

    Aromatic amines are an important group of industrial chemicals, which are widely used for manufacturing of dyes, pesticides, drugs, pigments, and other industrial products. These compounds have been considered highly toxic to human beings due to their carcinogenic nature. Three groups of aromatic amines have been recognized: monocyclic, polycyclic, and heterocyclic aromatic amines. Bacterial degradation of several monocyclic aromatic amines has been studied in a variety of bacteria, which utilizes monocyclic aromatic amines as their sole source of carbon and energy. Several degradation pathways have been proposed and the related enzymes and genes have also been characterized. Many reviews have been reviewed toxicity of monocyclic aromatic amines; however, there is lack of review on biodegradation of monocyclic aromatic amines. The aim of this review is to summarize bacterial degradation of monocyclic aromatic amines. This review will increase our current understanding of biochemical and molecular basis of bacterial degradation of monocyclic aromatic amines.

  13. In vitro screening of 50 highly prescribed drugs for thiol adduct formation--comparison of potential for drug-induced toxicity and extent of adduct formation.

    PubMed

    Gan, Jinping; Ruan, Qian; He, Bing; Zhu, Mingshe; Shyu, Wen C; Humphreys, W Griffith

    2009-04-01

    Reactive metabolite formation has been associated with drug-induced liver, skin, and hematopoietic toxicity of many drugs that has resulted in serious clinical toxicity, leading to clinical development failure, black box warnings, or, in some cases, withdrawal from the market. In vitro and in vivo screening for reactive metabolite formation has been proposed and widely adopted in the pharmaceutical industry with the aim of minimizing the property and thus the risk of drug-induced toxicity (DIT). One of the most common screening methods is in vitro thiol trapping of reactive metabolites. Although it is well-documented that many hepatotoxins form thiol adducts, there is no literature describing the adduct formation potential of safer drugs that are widely used. The objective of this study was to quantitatively assess the thiol adduct formation potential of 50 drugs (10 associated with DIT and 40 not associated) and document apparent differences in adduct formation between toxic and safer drugs. Dansyl glutathione was used as a trapping agent to aid the quantitation of adducts following in vitro incubation of drugs with human liver microsomes in the presence and absence of NADPH. Metabolic turnover of these drugs was also monitored by LC/UV. Overall, 15 out of the 50 drugs screened formed detectable levels of thiol adducts. There were general trends toward more positive findings in the DIT group vs the non-DIT group. These trends became more marked when the relative amount of thiol adducts was taken into account and improved further when dose and total daily reactive metabolite burdens were considered. In conclusion, there appears to be a general trend between the extent of thiol adduct formation and the potential for DIT, which would support the preclinical measurement and minimization of the property through screening of thiol adduct formation as part of an overall discovery optimization paradigm.

  14. Students' ways of understanding aromaticity and electrophilic aromatic substitution reactions

    NASA Astrophysics Data System (ADS)

    Duffy, Anne Merete

    Studies in organic chemistry education focus mainly on increasing students' performance. Studies from general chemistry education reveal that students' performance is not a good indicator of conceptual understanding. In support, Bhattacharyya and Bodner (2005) reveal that chemistry graduate students can produce correct answers to reaction mechanisms tasks in organic chemistry without understanding the underlying concepts behind the tasks. This dissertation uses the constructs of Harel's DNR-based instruction (1998, 2001, in press [a]) to categorize students' ways of understanding aromaticity and electrophilic aromatic substitution reactions. DNR refers to three instructional principles: Duality Principle, Necessity Principle and Repeated Reasoning Principle. Primarily, this study applies the following constructs integral to the Duality Principle: ways of understanding and ways of thinking. The purpose of this study is three-fold. The first purpose is to identify students' ways of understanding aromaticity and electrophilic aromatic substitution reactions and subsequently the ways of thinking that are inferred by these ways of understanding. The second purpose of this study is to provide quantitative evidence of students' beliefs (one category of ways of thinking) about learning organic chemistry. The third purpose is to show how we can help students develop more desirable ways of understanding aromaticity. First, several ways of understanding were identified from semi-structured interviews conducted with 12 undergraduate-level students. Three ways of thinking were inferred from these ways of understanding: (1) non-referential symbolic reasoning, (2) non-referential use of terminology, and (3) beliefs about learning organic chemistry. Second, the results of a 46-Item Likert-scale survey provided empirical evidence to support the claim that the students have a tendency towards memorization when learning organic chemistry. Third, this study demonstrated the potential

  15. Immunochemical detection of 4-hydroxynonenal protein adducts in oxidized hepatocytes.

    PubMed Central

    Uchida, K; Szweda, L I; Chae, H Z; Stadtman, E R

    1993-01-01

    We report here the development of an immunochemical procedure that uses an antibody specific to the 4-hydroxynonenal (HNE) moiety for the detection of HNE-protein adducts. The HNE-specific antibody was prepared by immunizing rabbits with a HNE-keyhole limpet hemocyanin conjugate and purifying the rabbit serum on an affinity gel prepared by covalent attachment of a HNE-conjugated heptapeptide. When various preparations of glyceraldehyde-3-phosphate dehydrogenase containing 0-7.0 equivalent of HNE-histidine residues per subunit were obtained by incubating samples of glyceraldehyde-3-phosphate dehydrogenase with increased amounts of HNE and subjected to immunoblotting with the HNE-specific antibody, the intensities of the blots were directly proportional to the number of HNE-histidine adducts as measured directly by amino acid analysis. Binding of the HNE-conjugated glyceraldehyde-3-phosphate dehydrogenase to the HNE-specific antibody could be completely inhibited by HNE-N-acetylhistidine, HNE-N-acetyllysine, or HNE-glutathione, suggesting that the antigenic determinant recognized by the antibody is the HNE moiety, not the HNE-amino acid conjugates, such as HNE-histidine, HNE-lysine, and HNE-cysteine. The utility of the HNE-specific antibody was demonstrated by its ability to react selectively with a number of HNE-protein adducts in immunoblot analyses of crude homogenates of rat liver hepatocytes that had been exposed to HNE or oxidative stresses with tert-butylhydroperoxide or metal-ion-catalyzed oxidation systems. Images Fig. 2 Fig. 4 Fig. 5 Fig. 6 PMID:8378358

  16. Aromatic-Aromatic Interactions in Biological System: Structure Activity Relationships

    SciTech Connect

    Rajagopal, Appavu; Deepa, Mohan; Govindaraju, Munisamy

    2016-02-26

    While, intramolecular hydrogen bonds have attracted the greatest attention in studies of peptide conformations, the recognition that several other weakly polar interactions may be important determinants of folded structure has been growing. Burley and Petsko provided a comprehensive overview of the importance of weakly polar interactions, in shaping protein structures. The interactions between aromatic rings, which are spatially approximate, have attracted special attention. A survey of the proximal aromatic residue pairs in proteins, allowed Burley and Petsko to suggest that, “phenyl ring centroids are separated by a preferential distance of between 4.5 and 7 Å, and dihedral angles approximately 90° are most common”.

  17. Adducts of rare-earth pivaloyltrifluoroacetonates with macrocyclic polyethers

    SciTech Connect

    Martynova, T.N.; Korchkov, V.P.; Nikulina, L.D.

    1986-07-01

    Adducts of lanthanide tris(pivaloyltrifluoroacetonates) with crown ethers having the formulas Ln(PTA)/sub 3/ x 18-crown-6 (Ln = La, Nd, Tb, Er, Lu) and Ln(PTA)/sub 3/ x dibenzo-18-crown-6 (Ln = Nd, Tb, Er) have been synthesized. The compounds obtained have been studied by the methods of elemental analysis, UV and IR spectroscopy, PMR, and mass spectroscopy. On the basis of the physicochemical properties and the spectra studied it has been concluded that the lanthanide tris(..beta..-diketonates) interact with the crown ethers.

  18. Acute adduction deficit in a 7-week-old infant.

    PubMed

    Jain, Sunila; Goulstine, David; Gottlob, Irene

    2002-12-01

    A 7-week-old infant with sudden onset adduction deficit and proptosis is reported. The main differential diagnoses included orbital myositis, orbital cellulitis, capillary haemangioma and rhabdomyosarcoma. A CT scan revealed a postseptal cellulitis-like picture with thickening of the medial rectus muscle. He was given a course of antibiotics, withholding steroids and biopsy. His condition resolved completely on high-dose antibiotics alone. To our knowledge this is the youngest patient with infectious orbital myositis and postseptal cellulitis described in the literature. The clinical course emphasizes the importance of administering sufficiently high doses of antibiotics.

  19. Tyrosine-lipid peroxide adducts from radical termination: para coupling and intramolecular Diels-Alder cyclization.

    PubMed

    Shchepin, Roman; Möller, Matias N; Kim, Hye-young H; Hatch, Duane M; Bartesaghi, Silvina; Kalyanaraman, Balaraman; Radi, Rafael; Porter, Ned A

    2010-12-15

    Free radical co-oxidation of polyunsaturated lipids with tyrosine or phenolic analogues of tyrosine gave rise to lipid peroxide-tyrosine (phenol) adducts in both aqueous micellar and organic solutions. The novel adducts were isolated and characterized by 1D and 2D NMR spectroscopy as well as by mass spectrometry (MS). The spectral data suggest that the polyunsaturated lipid peroxyl radicals give stable peroxide coupling products exclusively at the para position of the tyrosyl (phenoxy) radicals. These adducts have characteristic (13)C chemical shifts at 185 ppm due to the cross-conjugated carbonyl of the phenol-derived cyclohexadienone. The primary peroxide adducts subsequently undergo intramolecular Diels-Alder (IMDA) cyclization, affording a number of diastereomeric tricyclic adducts that have characteristic carbonyl (13)C chemical shifts at ~198 ppm. All of the NMR HMBC and HSQC correlations support the structure assignments of the primary and Diels-Alder adducts, as does MS collision-induced dissociation data. Kinetic rate constants and activation parameters for the IMDA reaction were determined, and the primary adducts were reduced with cuprous ion to give a phenol-derived 4-hydroxycyclohexa-2,5-dienone. No products from adduction of peroxyls at the phenolic ortho position were found in either the primary or cuprous reduction product mixtures. These studies provide a framework for understanding the nature of lipid-protein adducts formed by peroxyl-tyrosyl radical-radical termination processes. Coupling of lipid peroxyl radicals with tyrosyl radicals leads to cyclohexenone and cyclohexadienone adducts, which are of interest in and of themselves since, as electrophiles, they are likely targets for protein nucleophiles. One consequence of lipid peroxyl reactions with tyrosyls may therefore be protein-protein cross-links via interprotein Michael adducts.

  20. Depurinating acylfulvene-DNA adducts: characterizing cellular chemical reactions of a selective antitumor agent.

    PubMed

    Gong, Jiachang; Vaidyanathan, V G; Yu, Xiang; Kensler, Thomas W; Peterson, Lisa A; Sturla, Shana J

    2007-02-21

    Acylfulvenes (AFs) are a class of semisynthetic agents with high toxicity toward certain tumor cells, and for one analogue, hydroxymethylacylfulvene (HMAF), clinical trials are in progress. DNA alkylation by AFs, mediated by bioreductive activation, is believed to contribute to cytotoxicity, but the structures and chemical properties of corresponding DNA adducts are unknown. This study provides the first structural characterization of AF-specific DNA adducts. In the presence of a reductive enzyme, alkenal/one oxidoreductase (AOR), AF selectively alkylates dAdo and dGuo in reactions with a monomeric nucleoside, as well as in reactions with naked or cellular DNA, with 3-alkyl-dAdo as the apparently most abundant AF-DNA adduct. Characterization of this adduct was facilitated by independent chemical synthesis of the corresponding 3-alkyl-Ade adduct. In addition, in naked or cellular DNA, evidence was obtained for the formation of an additional type of adduct resulting from direct conjugate addition of Ade to AF followed by hydrolytic cyclopropane ring-opening, indicating the potential for a competing reaction pathway involving direct DNA alkylation. The major AF-dAdo and AF-dGuo adducts are unstable under physiologically relevant conditions and depurinate to release an alkylated nucleobase in a process that has a half-life of 8.5 h for 3-alkyladenine and less than approximately 2 h for dGuo adducts. DNA alkylation further leads to single-stranded DNA cleavage, occurring exclusively at dGuo and dAdo sites, in a nonsequence-specific manner. In AF-treated cells that were transfected with either AOR or control vectors, the DNA adducts identified match those from in vitro studies. Moreover, a positive correlation was observed between DNA adduct levels and cell sensitivity to AF. The potential contributing roles of AOR-mediated bioactivation and adduct stability to the cytotoxicity of AF are discussed.

  1. Aromatic components in cometary materials

    NASA Technical Reports Server (NTRS)

    Allamandola, Louis J.; Sandford, Scott A.; Wopenka, B.

    1988-01-01

    The Raman spectra of interplanetary dust particles (IDPs) collected in the stratosphere show that two bands at about 1350 and 1600 delta/cm and a broader feature between 2200 and 3300 delta/cm that are characteristic of aromatic molecular units with ordered domains smaller than 25 A in diameter. This suggests that the carbonaceous material in IDPs may be similar to the polymeric component seen in meteorites, where this material is thought to consist of aromatic molecular units that are randomly interlinked by short aliphatic bridges. The features in the Raman spectra of IDPs are similar in position, and relative strength to interstellar infrared emission features that have been attributed to vibrational transitions in free molecular polycyclic aromatic hydrocarbons. Taken together, these observations suggest that some fraction of the carbonaceous materials in IDPs may have been produced in circumstellar dust shells and only slightly modified in interstellar space.

  2. Detection of chlorinated aromatic compounds

    DOEpatents

    Ekechukwu, Amy A.

    1996-01-01

    A method for making a composition for measuring the concentration of chloated aromatic compounds in aqueous fluids, and an optical probe for use with the method. The composition comprises a hydrophobic polymer matrix, preferably polyamide, with a fluorescent indicator uniformly dispersed therein. The indicator fluoresces in the presence of the chlorinated aromatic compounds with an intensity dependent on the concentration of these compounds in the fluid of interest, such as 8-amino-2-naphthalene sulfonate. The probe includes a hollow cylindrical housing that contains the composition in its distal end. The probe admits an aqueous fluid to the probe interior for exposure to the composition. An optical fiber transmits excitation light from a remote source to the composition while the indicator reacts with chlorinated aromatic compounds present in the fluid. The resulting fluorescence light signal is reflected to a second optical fiber that transmits the light to a spectrophotometer for analysis.

  3. Detection of chlorinated aromatic compounds

    DOEpatents

    Ekechukwu, A.A.

    1996-02-06

    A method for making a composition for measuring the concentration of chlorinated aromatic compounds in aqueous fluids, and an optical probe for use with the method are disclosed. The composition comprises a hydrophobic polymer matrix, preferably polyamide, with a fluorescent indicator uniformly dispersed therein. The indicator fluoresces in the presence of the chlorinated aromatic compounds with an intensity dependent on the concentration of these compounds in the fluid of interest, such as 8-amino-2-naphthalene sulfonate. The probe includes a hollow cylindrical housing that contains the composition in its distal end. The probe admits an aqueous fluid to the probe interior for exposure to the composition. An optical fiber transmits excitation light from a remote source to the composition while the indicator reacts with chlorinated aromatic compounds present in the fluid. The resulting fluorescence light signal is reflected to a second optical fiber that transmits the light to a spectrophotometer for analysis. 5 figs.

  4. A fluorescent-based HPLC assay for quantification of cysteine and cysteamine adducts in Escherichia coli-derived proteins.

    PubMed

    Soriano, Brian D; Tam, Lei-Ting T; Lu, Hsieng S; Valladares, Violeta G

    2012-01-01

    Recombinant proteins expressed in Escherichia coli are often produced as unfolded, inactive forms accumulated in inclusion bodies. Redox-coupled thiols are typically employed in the refolding process in order to catalyze the formation of correct disulfide bonds at maximal folding efficiency. These thiols and the recombinant proteins can form mixed disulfide bonds to generate thiol-protein adducts. In this work, we apply a fluorescent-based assay for the quantification of cysteine and cysteamine adducts as observed in E. coli-derived proteins. The thiols are released by reduction of the adducted protein, collected and labeled with a fluorescent reagent, 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate. The derivatized thiols are separated by reversed-phase HPLC and can be accurately quantified after method optimization. The estimated thiol content represents total amount of adducted forms present in the analyzed samples. The limit of quantification (LOQ) was established; specifically, the lowest amount of quantifiable cysteine adduction is 30 picograms and the lowest amount of quantifiable cysteamine adduction is 60 picograms. The assay is useful for quantification of adducts in final purified products as well as in-process samples from various purification steps. The assay indicates that the purification process accomplishes a decrease in cysteine adduction from 0.19 nmol adduct/nmol protein to 0.03 nmol adduct/nmol protein as well as a decrease in cysteamine adduction from 0.24 nmol adduct/nmol protein to 0.14 nmol adduct/nmol protein.

  5. Polyphenylquinoxalines via Aromatic Nucleophilic Displacement

    NASA Technical Reports Server (NTRS)

    Hergenrother, Paul M.; Connell, John W.

    1988-01-01

    Polyphenylquinoxalines are produced by an aromatic nucleophilic displacement reaction involving an activated aromatic dihalide with an appropriate quinoxaline monomer. Polyphenylquinoxalines are high temperature thermoplastics used as adhesives, coatings, films and composite matrices. The novelty of this invention is threefold: (1) some of the quinoxaline monomers are new compositions of matter; (2) the phenylquinoxaline polymers which are the end products of the invention are new compositions of matter; and (3) the method of forming the polymers is novel, replacing a more costly prior art process, which is also limited in the kinds of products prepared therefrom.

  6. Nuclear magnetic resonance solution structure of an N(2)-guanine DNA adduct derived from the potent tumorigen dibenzo[a,l]pyrene: intercalation from the minor groove with ruptured Watson-Crick base pairing.

    PubMed

    Tang, Yijin; Liu, Zhi; Ding, Shuang; Lin, Chin H; Cai, Yuqin; Rodriguez, Fabian A; Sayer, Jane M; Jerina, Donald M; Amin, Shantu; Broyde, Suse; Geacintov, Nicholas E

    2012-12-04

    The most potent tumorigen identified among the polycyclic aromatic hydrocarbons (PAH) is the nonplanar fjord region dibenzo[a,l]pyrene (DB[a,l]P). It is metabolically activated in vivo through the widely studied diol epoxide (DE) pathway to form covalent adducts with DNA bases, predominantly guanine and adenine. The (+)-11S,12R,13R,14S DE enantiomer forms adducts via its C14 position with the exocyclic amino group of guanine. Here, we present the first nuclear magnetic resonance solution structure of a DB[a,l]P-derived adduct, the 14R-(+)-trans-anti-DB[a,l]P-N(2)-dG (DB[a,l]P-dG) lesion in double-stranded DNA. In contrast to the stereochemically identical benzo[a]pyrene-derived N(2)-dG adduct (B[a]P-dG) in which the B[a]P rings reside in the B-DNA minor groove on the 3'-side of the modifed deoxyguanosine, in the DB[a,l]P-derived adduct the DB[a,l]P rings intercalate into the duplex on the 3'-side of the modified base from the sterically crowded minor groove. Watson-Crick base pairing of the modified guanine with the partner cytosine is broken, but these bases retain some stacking with the bulky DB[a,l]P ring system. This new theme in PAH DE-DNA adduct conformation differs from (1) the classical intercalation motif in which Watson-Crick base pairing is intact at the lesion site and (2) the base-displaced intercalation motif in which the damaged base and its partner are extruded from the helix. The structural considerations that lead to the intercalated conformation of the DB[a,l]P-dG lesion in contrast to the minor groove alignment of the B[a]P-dG adduct, and the implications of the DB[a,l]P-dG conformational motif for the recognition of such DNA lesions by the human nucleotide excision repair apparatus, are discussed.

  7. Conformational preferences of DNA following damage by aristolochic acids: Structural and energetic insights into the different mutagenic potential of the ALI and ALII-N(6)-dA adducts.

    PubMed

    Kathuria, Preetleen; Sharma, Purshotam; Abendong, Minette N; Wetmore, Stacey D

    2015-04-21

    Aristolochic acids (AAI and AAII), produced by the Aristolochiaceae family of plants, are classified as group I (human) carcinogens by the International Agency for Research on Cancer. These acids are metabolized in cells to yield aristolactams (ALI and ALII, respectively), which further form bulky adducts with the purine nucleobases. Specifically, the adenine lesions are more persistent in cells and have been associated with chronic renal diseases and related carcinogenesis. To understand the structural basis of the nephrotoxicity induced by AAs, the ALI-N(6)-dA and ALII-N(6)-dA lesions are systematically studied using computational methods. Density functional theory calculations indicate that the aristolactam moiety intrinsically prefers a planar conformation with respect to adenine. Nucleoside and nucleotide models suggest that the anti and syn orientations about the glycosidic bond are isoenergetic for both adducts. Molecular dynamics simulations and free energy calculations reveal that the anti base-displaced intercalated conformation is the most stable conformer for both types of AL-N(6)-dA adducted DNA, which agrees with previous experimental work on the ALII-N(6)-dA adduct and thereby validates our approach. Interestingly, this conformer differs from the dominant conformations adopted by other N6-linked adenine lesions, including those derived from polycyclic aromatic hydrocarbons. Furthermore, the second most stable syn base-displaced intercalated conformation lies closer in energy to the anti base-displaced intercalated conformation for ALI-N(6)-dA compared to ALII-N(6)-dA. This indicates that a mixture of conformations may be detectable for ALI-N(6)-dA in DNA. If this enhanced conformational flexibility of double-stranded DNA persists when bound to a lesion-bypass polymerase, this provides a possible structural explanation for the previously observed greater nephrotoxic potential for the ALI versus ALII-N(6)-dA adduct. In addition, the structural

  8. NMR solution structure of an N2-guanine DNA adduct derived from the potent tumorigen dibenzo[a,l]pyrene: Intercalation from the minor groove with ruptured Watson-Crick base pairing

    PubMed Central

    Tang, Yijin; Liu, Zhi; Ding, Shuang; Lin, Chin H.; Cai, Yuqin; Rodriguez, Fabian A.; Sayer, Jane M.; Jerina, Donald M.; Amin, Shantu; Broyde, Suse; Geacintov, Nicholas E.

    2012-01-01

    The most potent tumorigen identified among the polycyclic aromatic hydrocarbons (PAH) is the non-planar fjord region dibenzo[a,l]pyrene (DB[a,l]P). It is metabolically activated in vivo through the widely-studied diol epoxide (DE) pathway to form covalent adducts with DNA bases, predominantly guanine and adenine. The (+)-11S,12R,13R,14S DE enantiomer forms adducts via its C14-position with the exocyclic amino group of guanine. Here, we present the first NMR solution structure of a DB[a,l]P-derived adduct, the 14R (+)-trans-anti-DB[a,l]P–N2-dG (DB[a,l]P-dG) lesion in double-stranded DNA. In contrast to the stereochemically identical benzo[a]pyrene-derived N2-dG adduct (B[a]P-dG) in which the B[a]P rings reside in the B-DNA minor groove on the 3’-side of the modifed deoxyguanosine, in the DB[a,l]P-derived adduct the DB[a,l]P rings intercalate into the duplex on the 3’-side of the modified base from the sterically crowded minor groove. Watson-Crick base pairing of the modified guanine with the partner cytosine is broken, but these bases retain some stacking with the bulky DB[a,l]P ring system. This new theme in PAH DE - DNA adduct conformation differs from: (1) the classical intercalation motif where Watson-Crick base-pairing is intact at the lesion site, and (2) the base-displaced intercalation motif in which the damaged base and its partner are extruded from the helix . The structural considerations that lead to the intercalated conformation of the DB[a,l]P-dG lesion in contrast to the minor groove alignment of the B[a]P-dG adduct, and the implications of the DB[a,l]P-dG conformational motif for the recognition of such DNA lesions by the human nucleotide excision repair apparatus, are discussed. PMID:23121427

  9. Detection and quantitation of N-(deoxyguanosin-8-yl)-2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine adducts in DNA using online column-switching liquid chromatography tandem mass spectrometry

    PubMed Central

    Singh, Rajinder; Arlt, Volker M.; Henderson, Colin J.; Phillips, David H.; Farmer, Peter B.; da Costa, Gonçalo Gamboa

    2010-01-01

    The heterocyclic aromatic amine, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) is formed by the grilled cooking of certain foods such as meats, poultry and fish. PhIP has been shown to induce tumours in the colon, prostate and mammary glands of rats and is regarded as a potential human dietary carcinogen. PhIP is metabolically activated via cytochrome P450 mediated oxidation to an N-hydroxylamino-PhIP intermediate that is subsequently converted to an ester by N-acetyltransferases or sulfotransferases and undergoes heterolytic cleavage to produce a PhIP-nitrenium ion, which reacts with DNA to form the N-(deoxyguanosin-8-yl)-2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP-C8-dG) adduct. Thus far, the detection and quantification of PhIP-DNA adducts has relied to a large extent on 32P-postlabelling methodologies. In order to expand the array of available techniques for the detection and improved quantification of PhIP-C8-dG adducts in DNA we have developed an online column-switching liquid chromatography (LC)-electrospray ionization (ESI)-tandem mass spectrometry (MS/MS) selected reaction monitoring (SRM) method incorporating an isotopically [13C10]-labelled PhIP-C8-dG internal standard for the analysis of DNA enzymatically hydrolysed to 2′-deoxynucleosides. A dose-dependent increase was observed for PhIP-C8-dG adducts when salmon testis DNA was reacted with N-acetoxy-PhIP. Analysis of DNA samples isolated from colon tissue of mice treated by oral gavage daily for 5 days with 50 mg/kg body weight of PhIP resulted in the detection of an average level of 14.8 ± 3.7 PhIP-C8-dG adducts per 106 2′-deoxynucleosides. The method required 50 μg of hydrolysed animal DNA on column and the limit of detection for PhIP-C8-dG was 2.5 fmol (1.5 PhIP-C8-dG adducts per 108 2′-deoxynucleosides). In summary, the LC-ESI-MS/MS SRM method provides for the rapid automation of the sample clean up and a reduction in matrix components that would otherwise interfere with

  10. Volatile profiles of aromatic and non-aromatic rice

    USDA-ARS?s Scientific Manuscript database

    Rice is enjoyed by many people as a staple food because of its flavor and texture. Some scented varieties command a premium in the marketplace because of their distinctive aroma and flavor. The compound most commonly associated with the popcorn or nutty scent of aromatic rice is 2-acetyl-1-pyrroline...

  11. 32P-postlabeling analysis of adducts formed between DNA and safrole 2',3'-epoxide: absence of adduct formation in vivo.

    PubMed

    Qato, M K; Guenthner, T M

    1995-01-01

    We have used the 32P-postlabeling technique to examine the binding of safrole 2',3'-oxide to DNA. At least 8 covalent adducts are formed when calf thymus DNA is incubated with this oxygenated metabolite of safrole in vitro. However, no corresponding adducts are formed with liver DNA when whole animals are exposed to safrole 2',3'-oxide, or safrole itself. Although safrole 2',3'-oxide is readily formed in vivo, and is sufficiently reactive to covalently bind to DNA, it is probably not a factor in the in vivo genotoxicity of safrole. We also demonstrate that adducts with similar mobility to the major safrole 2',3'-oxide-DNA adduct are formed in vitro between safrole 2',3'-oxide and deoxyguanosine, and also between its chemical analogs allylbenzene 2',3'-oxide or estragole 2',3'-oxide and DNA.

  12. Turned head--adducted hip--truncal curvature syndrome.

    PubMed Central

    Hamanishi, C; Tanaka, S

    1994-01-01

    One hundred and eight neonates and infants who showed the clinical triad of a head turned to one side, adduction contracture of the hip joint on the occipital side of the turned head, and truncal curvature, which we named TAC syndrome, were studied. These cases included seven with congenital and five with late infantile dislocations of the hip joint and 14 who developed muscular torticollis. Forty one were among 7103 neonates examined by one of the authors. An epidemiological analysis confirmed the aetiology of the syndrome to be environmental. The side to which the head was turned and that of the adducted hip contracture showed a high correlation with the side of the maternal spine on which the fetus had been lying. TAC syndrome is an important asymmetrical deformity that should be kept in mind during neonatal examination, and may be aetiologically related to the unilateral dislocation of the hip joint, torticollis, and infantile scoliosis which develop after a vertex presentation. Images PMID:8048823

  13. Nonstoichiometric Adduct Approach for High-Efficiency Perovskite Solar Cells.

    PubMed

    Park, Nam-Gyu

    2017-01-03

    Since the groundbreaking report on a solid-state perovskite solar cell employing a methylammonium lead iodide-sensitized mesoporous TiO2 film and an organic hole conducting layer in 2012 by our group, the swift surge of perovskite photovoltaics opens a new paradigm in solar-cell research. As a result, ca. 1300 peer-reviewed research articles were published in 2015. In this Inorganic Chemistry Forum on Halide Perovskite, the researches with highlights of work on perovskite solar cells in my laboratory are reviewed. We have developed a size-controllable two-step spin-coating method and found that minimal nonradiative recombination in perovskite crystals could lead to high photovoltaic performance. A Lewis acid based adduct method and self-formed grain boundary process were developed for high-efficiency devices with reproducibility. A power conversion efficiency of 20.4% was achieved via grain boundary engineering based on a nonstoichiometric adduct approach. The incorporation of cesium in a formamidinium lead iodide perovskite was found to show better photostability and moisture-stability. A reduction in the dimensionality from a three-dimensitonal nanocrystal to a one-dimensional nanowire led to a hypsochromic shift of absorption and fluorescence. To enhance the charge-carrier transport and light-harvesting efficiency, a nanoarchitecture of oxide layers was proposed.

  14. Kinetics, mechanism and thermodynamics of bisulfite-aldehyde adduct formation

    SciTech Connect

    Olson, T.M.; Boyce, S.D.; Hoffmann, M.R.

    1986-04-01

    The kinetics and mechanism of bisulfite addition to benzaldehyde were studied at low pH in order to assess the importance of this reaction in stabilizing S(IV) in fog-, cloud-, and rainwater. Previously, the authors established that appreciable concentrations of the formaldehyde-bisulfite adduct (HMSA) are often present in fogwater. Measured HMSA concentrations in fogwater often do not fully account for observed excess S(IV) concentrations, however, so that other S(IV)-aldehyde adducts may be present. Reaction rates were determined by monitoring the disappearance of benzaldehyde by U.V. spectrophotometry under pseudo-first order conditions, (S(IV))/sub T/ >>(phi-CHO)/sub T/, in the pH range 0 - 4.4 at 25/sup 0/C. The equilibrium constant was determined by dissolving the sodium salt of the addition compound in a solution adjusted to pH 3.9, and measuring the absorbance of the equilibrated solution at 250 nm. A literature value of the extinction coefficient for benzaldehyde was used to calculate the concentration of free benzaldehyde. All solutions were prepared under an N/sub 2/ atmosphere using deoxygenated, deionized water and ionic strength was maintained at 1.0 M with sodium chloride.

  15. Nitropyrene: DNA binding and adduct formation in respiratory tissues.

    PubMed Central

    Jackson, M A; King, L C; Ball, L M; Ghayourmanesh, S; Jeffrey, A M; Lewtas, J

    1985-01-01

    Binding of 1-nitro (14C)pyrene (NP) or its metabolites to cellular DNA and protein in cultures of rabbit alveolar macrophages, lung tissue, and tracheal tissue was examined. DNA binding in tracheal tissue (136 +/- 18.3 pmole NP/mg DNA) was four to five times the levels measured in either lung tissue (38 +/- 9.4 pmole NP/mg DNA) or macrophages (26 +/- 7.5 pmole NP/mg DNA). Adduct analysis of DNA isolated from lung tissue incubated with 1-nitro[H3]pyrene in vitro resulted in the identification of 2 to 5% of the NP adducts as C8-deoxyguanosine 1-aminopyrene. NP was also bound to cellular protein in tracheal tissue and lung tissue, and at a lower level in macrophages. Cocultivation of the macrophages with lung and tracheal tissue decreased the DNA binding in tracheal tissue by 45%. Following intratracheal instillation of diesel particles (5 mg) vapor-coated with 14C-NP (380 ppm, 0.085 muCi/mg) particles into rats, 5-8% of the radioactivity remained in the lungs after 20 hr. Most of the diesel particles were also deposited in the lung. Examination of DNA and protein binding in this tissue showed 5 to 12% of the pulmonary 14C bound to protein and no detectable levels of 14C bound to DNA. PMID:3841313

  16. Inert Reassessment Document for Poly(oxyethylene) adducts of mixed phytosterols

    EPA Pesticide Factsheets

    Poly(oxyethy1ene) adducts of mixed phytosterols is uncategorized as to list classification status. Based upon the reasonable certainty of no harm safety finding, the List 4B classification for poly(oxyethy1ene) adducts of mixed phytosterols is affirmed.

  17. Condensed tannin-resorcinol adducts and their use in wood-laminating adhesives: An exploratory study

    Treesearch

    Richard W. Hemingway; R.E. Kreibich

    1984-01-01

    The reaction of a tannin extract (containing about 30% carbohydrate) from loblolly pine (Pinus taeda L.) bark (two parts) and resorcinol (one part) at 120°C for 24 h with acetic acid catalyst gave a product containing predominantly oligomeric procyanidin-4-resorcinol adducts (39%), unreacted resorcinol (22%), carbohydrate (20%). the resorcinol adduct...

  18. A hydrogen bond scaffold supported synthetic heme Fe(III)-O2(-) adduct.

    PubMed

    Mittra, Kaustuv; Chatterjee, Sudipta; Samanta, Subhra; Sengupta, Kushal; Bhattacharjee, Hridaynath; Dey, Abhishek

    2012-11-04

    A hydrogen bonded heme-Fe(III)-O(2)(-) adduct is stabilized and characterized using resonance Raman and EPR spectroscopy. The low O-O vibrations of this complex are quite different from those reported for other heme-Fe(III)-O(2)(-) adducts.

  19. 40 CFR 721.1850 - Toluene sulfonamide bis-phe-nol A epoxy adduct.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Toluene sulfonamide bis-phe-nol A... Specific Chemical Substances § 721.1850 Toluene sulfonamide bis-phe-nol A epoxy adduct. (a) Chemical... as toluene sulfonamide bisphenol A epoxy adduct (PMN P-90-113) is subject to reporting under this...

  20. 40 CFR 721.1850 - Toluene sulfonamide bis-phe-nol A epoxy adduct.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Toluene sulfonamide bis-phe-nol A... Specific Chemical Substances § 721.1850 Toluene sulfonamide bis-phe-nol A epoxy adduct. (a) Chemical... as toluene sulfonamide bisphenol A epoxy adduct (PMN P-90-113) is subject to reporting under this...

  1. 40 CFR 721.1850 - Toluene sulfonamide bis-phe-nol A epoxy adduct.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Toluene sulfonamide bis-phe-nol A... Specific Chemical Substances § 721.1850 Toluene sulfonamide bis-phe-nol A epoxy adduct. (a) Chemical... as toluene sulfonamide bisphenol A epoxy adduct (PMN P-90-113) is subject to reporting under this...

  2. 40 CFR 721.1850 - Toluene sulfonamide bis-phe-nol A epoxy adduct.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Toluene sulfonamide bis-phe-nol A... Specific Chemical Substances § 721.1850 Toluene sulfonamide bis-phe-nol A epoxy adduct. (a) Chemical... as toluene sulfonamide bisphenol A epoxy adduct (PMN P-90-113) is subject to reporting under this...

  3. Detection, characterization, and decay kinetics of ROS and thiyl adducts of mito-DEPMPO spin trap.

    PubMed

    Hardy, Micaël; Rockenbauer, Antal; Vásquez-Vivar, Jeannette; Felix, Christopher; Lopez, Marcos; Srinivasan, Satish; Avadhani, Narayan; Tordo, Paul; Kalyanaraman, B

    2007-07-01

    We report here the detection and characterization of spin adducts formed from the trapping of reactive oxygen species (superoxide and hydroxyl radicals) and glutathiyl and carbon-centered radicals by a newly synthesized nitrone, Mito-DEPMPO. This is a cationic nitrone spin trap with a triphenyl phosphonium cation conjugated to the DEPMPO analogue. The Mito-DEPMPO-OOH adduct, formed from the trapping of superoxide by Mito-DEPMPO, was enzymatically generated using xanthine/xanthine oxidase and neuronal nitric oxide synthase, and chemically generated by KO2 in 18-crown-6. The Mito-DEPMPO-OOH adduct exhibits an eight-line EPR spectrum with partial asymmetry arising from the alternate line-width effect. The half-life of the Mito-DEPMPO-OOH adduct is 2-2.5-times greater than that of the DEPMPO-OOH. The Mito-DEPMPO-SG adduct, formed from the trapping of glutathiyl radicals by Mito-DEPMPO, is 3-times more persistent than the analogue DEPMPO-SG adduct. In this study, we describe the EPR characterization of spin adducts formed from Mito-DEPMPO. The EPR parameters of Mito-DEPMPO adducts are distinctly different and highly characteristic. The detection of superoxide from an intact mitochondrion was feasible with Mito-DEPMPO but not with DEPMPO. We conclude that Mito-DEPMPO nitrone and its analogues are more effective than most nitrone spin traps for trapping superoxide, hydroxyl, and thiyl radicals formed in biological systems, including mitochondria.

  4. Depurinating naphthalene–DNA adducts in mouse skin related to cancer initiation

    PubMed Central

    Saeed, Muhammad; Higginbotham, Sheila; Gaikwad, Nilesh; Chakravarti, Dhrubajyoti; Rogan, Eleanor; Cavalieri, Ercole

    2015-01-01

    Naphthalene has been shown to be a weak carcinogen in rats. To investigate its mechanism of metabolic activation and cancer initiation, mice were topically treated with naphthalene or one of its metabolites, 1-naphthol, 1,2-dihydrodiolnaphthalene (1,2-DDN), 1,2-dihydroxynaphthalene (1,2-DHN), and 1,2-naphthoquinone (1,2-NQ). After 4 h, the mice were sacrificed, the treated skin was excised, and the depurinating and stable DNA adducts were analyzed. The depurinating adducts were identified and quantified by ultraperformance liquid chromatography/tandem mass spectrometry, whereas the stable adducts were quantified by 32P-postlabeling. For comparison, the stable adducts formed when a mixture of the four deoxyribonucleoside monophosphates was treated with 1,2-NQ or enzyme-activated naphthalene were also analyzed. The depurinating adducts 1,2-DHN-1-N3Ade and 1,2-DHN-1-N7Gua arise from reaction of 1,2-NQ with DNA. Similarly, the major stable adducts appear to derive from the 1,2-NQ. The depurinating DNA adducts are, in general, the most abundant. Therefore, naphthalene undergoes metabolic activation to the electrophilic ortho-quinone, 1,2-NQ, which reacts with DNA to form depurinating adducts. This is the same mechanism as other weak carcinogens, such as the natural and synthetic estrogens, and benzene. PMID:19619639

  5. 40 CFR 721.3700 - Fatty acid, ester with styrenated phenol, ethylene oxide adduct.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... phenol, ethylene oxide adduct. 721.3700 Section 721.3700 Protection of Environment ENVIRONMENTAL..., ethylene oxide adduct. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substance identified generically as fatty acid, ester with styrenated phenol, ethylene...

  6. 40 CFR 721.3700 - Fatty acid, ester with styrenated phenol, ethylene oxide adduct.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... phenol, ethylene oxide adduct. 721.3700 Section 721.3700 Protection of Environment ENVIRONMENTAL..., ethylene oxide adduct. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substance identified generically as fatty acid, ester with styrenated phenol, ethylene...

  7. 40 CFR 721.3700 - Fatty acid, ester with styrenated phenol, ethylene oxide adduct.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... phenol, ethylene oxide adduct. 721.3700 Section 721.3700 Protection of Environment ENVIRONMENTAL..., ethylene oxide adduct. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substance identified generically as fatty acid, ester with styrenated phenol, ethylene...

  8. 40 CFR 721.3700 - Fatty acid, ester with styrenated phenol, ethylene oxide adduct.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... phenol, ethylene oxide adduct. 721.3700 Section 721.3700 Protection of Environment ENVIRONMENTAL..., ethylene oxide adduct. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substance identified generically as fatty acid, ester with styrenated phenol, ethylene...

  9. 40 CFR 721.3700 - Fatty acid, ester with styrenated phenol, ethylene oxide adduct.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... phenol, ethylene oxide adduct. 721.3700 Section 721.3700 Protection of Environment ENVIRONMENTAL..., ethylene oxide adduct. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substance identified generically as fatty acid, ester with styrenated phenol, ethylene...

  10. Immunohistochemical localization of trichloroacylated protein adducts in tetrachloroethene-treated mice.

    PubMed

    Green, S M; Khan, M F; Kaphalia, B S; Ansari, G A

    2001-05-25

    Tetrachloroethene (PCE), a common industrial solvent and environmental contaminant, is primarily used in the dry-cleaning industry. The toxicity of PCE has been linked to vision disorders, renal and hepatic cancer, and autoimmune diseases. Although the mechanism of toxicity is not fully understood, PCE forms trichloroacylated protein adducts in tissues where toxicity is known to occur. These adducts may be responsible for toxicity by altering the function of cellular proteins. Using Western blot analysis, formation of trichloroacylated protein adducts has been reported. To determine the localization of the adducts in a specific zone of a tissue, immunohistochemical staining was used in the study. An antiserum to trichloroacylated proteins was raised in rabbits and its specificity was established by enzyme-linked immunosorbent assay (ELISA). Female MRL-lpr/lpr and MRL +/+ mice were treated with PCE using a single 5-mmol/kg dose over 24 h or on every fourth day for 6 wk (total 20 doses). Formation of trichloroacylated protein adducts was observed in the liver, and localized to the centrilobular zones. Intensity and circumference of the staining around the central vein were much greater in subchronically treated mice than in acutely treated mice. No immunochemical reactivity was observed in any of the other tissues examined. This study shows that hepatic trichloroacylated protein adducts are localized in a region of the liver where PCE-mediated toxicity is known to occur. Immunohistochemical localization of these adducts and its association with PCE-induced toxicity support the contention that adducts may contribute to toxicity.

  11. THE PHOTOTOXICITY OF POLYCYCLIC AROMATIC HYDROCARBONS

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) continues to be interested in developing methods for the detection of polycyclic aromatic hydrocarbons (PAHS) in the environment. Polycyclic aromatic hydrocarbons (PAHS) are common contaminants in our environment. Being major product...

  12. THE PHOTOTOXICITY OF POLYCYCLIC AROMATIC HYDROCARBONS

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) continues to be interested in developing methods for the detection of polycyclic aromatic hydrocarbons (PAHS) in the environment. Polycyclic aromatic hydrocarbons (PAHS) are common contaminants in our environment. Being major product...

  13. Identification of adducts between an odoriferous volatile thiol and oxidized grape phenolic compounds: kinetic study of adduct formation under chemical and enzymatic oxidation conditions.

    PubMed

    Nikolantonaki, Maria; Jourdes, Michael; Shinoda, Kentaro; Teissedre, Pierre-Louis; Quideau, Stéphane; Darriet, Philippe

    2012-03-14

    HPLC-MS and (1)H, (13)C, and 2D NMR analyses were used to identify new addition products between 3-sulfanylhexan-1-ol (3SH) and o-quinones derived from (+)-catechin, (-)-epicatechin, and caftaric acid. The kinetics of formation of these adducts were monitored in a wine model solution and in a must-like medium by HPLC-UV-MS with the aim of understanding the chemical mechanism involved in reactions between volatile thiols and o-quinones. One o-quinone-caftaric acid/3SH adduct, three o-quinone-(+)-catechin/3SH adducts, and three o-quinone-(-)-epicatechin/3SH adducts were characterized. Caftaric acid was oxidized faster than (-)-epicatechin and (+)-catechin when these phenolic compounds were incubated in a one-component mixture with polyphenoloxidase (PPO) in the presence of 3SH. Consequently, o-quinone-caftaric acid formed adducts with 3SH more rapidly than o-quinone-(+)-catechin and o-quinone-(-)-epicatechin in the absence of other nucleophilic species. Furthermore, o-quinone-(-)-epicatechin reacted faster than o-quinone-(+)-catechin with 3SH. Sulfur dioxide decreased the yield of adduct formation to a significant extent. Under chemical oxidation conditions, the rates and yields of adduct formation were lower than those observed in the presence of PPO, and o-quinone-caftaric acid was slightly less reactive with 3SH, compared to oxidized flavan-3-ols. The identification of o-quinone-caftaric acid/3SH and o-quinone-(+)-catechin/3SH adducts in a must matrix suggests that the proposed reaction mechanism is responsible for 3SH loss in dry wines during their vinification and aging process.

  14. Assessment of Interactions between PAH Exposure and Genetic Polymorphisms on PAH-DNA Adducts in African American, Dominican, and Caucasian Mothers and Newborns

    PubMed Central

    Wang, Shuang; Chanock, Stephen; Tang, Deliang; Li, Zhigang; Jedrychowski, Wieslaw; Perera, Frederica P.

    2011-01-01

    Polycyclic aromatic hydrocarbons (PAH) are widespread pollutants commonly found in air, food, and drinking water. Benzo[a]pyrene is a well-studied representative PAH found in air from fossil fuel combustion and a transplacental carcinogen experimentally. PAHs bind covalently to DNA to form DNA adducts, an indicator of DNA damage, and an informative biomarker of potential cancer risk. Associations between PAH-DNA adduct levels and both cancer risk and developmental deficits have been seen in previous experimental and epidemiologic studies. Several genes have been shown to play an important role in the metabolic activation or detoxification of PAHs, including the cytochrome P450 genes CYP1A1 and CYP1B1 and the glutathione S-transferase (GST) genes GSTM1, and GSTT2. Genetic variation in these genes could influence susceptibility to adverse effects of PAHs in polluted air. Here, we have explored interactions between prenatal PAH exposure and 17 polymorphisms in these genes (rs2198843, rs1456432, rs4646903, rs4646421, rs2606345, rs7495708, rs2472299, rs162549, rs1056837, rs1056836, rs162560, rs10012, rs2617266, rs2719, rs1622002, rs140194, and gene deletion GSTM1-02) and haplotypes on PAH-DNA adducts in cord blood of 547 newborns and in maternal blood of 806 mothers from three different self-described ethnic groups: African Americans, Dominicans, and Caucasians. PAHs were measured by personal air monitoring of mothers during pregnancy. Significant interactions (p < 0.05) were observed between certain genetic polymorphisms and CYP1A1 haplotype and PAHs in mothers and their newborns in the three ethnic groups. However, with our limited sample size, the current findings are suggestive only, warranting further study. PMID:18268125

  15. Cytochrome P450 system expression and DNA adduct formation in the liver of Zacco platypus following waterborne benzo(a)pyrene exposure: implications for biomarker determination.

    PubMed

    Lee, Jin Wuk; Kim, Yong Hwa; Yoon, Seokjoo; Lee, Sung Kyu

    2014-09-01

    Benzo(a)pyrene (BaP) is a polycyclic aromatic hydrocarbon that causes mutations and tumor formation. Zacco platypus is a sentinel species that is suitable for monitoring aquatic environments. We studied cytochrome P450 system (CYP system) expression and DNA adduct formation in the liver of Z. platypus following waterborne exposure to BaP. The results showed both dose and time dependency. The significant induction levels of CYP system mRNA and protein reached maximums at 2 days and 14 days, respectively, and hepatosomatic index was maximally induced at 4 days during 14 days BaP exposure. DNA adduct formation was significantly induced compared to corresponding controls (t-test, p < 0.01) after 4 days of exposure in 100 μg/L BaP. These results indicate that the only use of mRNA expression level of CYP system as a biomarker make us underestimate prolonged toxicity (4-14 days) of BaP and the only use of protein expression level of CYP system make us underestimate acute toxicity (1-2 days) of BaP. Therefore, we suggests that a combinational use of the mRNA expression level and protein expression level of CYP system, hepatosomatic index is a useful biomarker in risk assessment of waterborne BaP exposure. In addition, DNA adduct formation was a useful biomarker in risk assessment of waterborne BaP exposure at 4 days. CYP1A was a more sensitive biomarker than CYP reductase for BaP exposure when considering both the mRNA and protein level. Furthermore, our results show that Z. platypus is a useful species for assessing the risk of waterborne BaP exposure. Copyright © 2012 Wiley Periodicals, Inc., a Wiley company.

  16. Assessment of interactions between PAH exposure and genetic polymorphisms on PAH-DNA adducts in African American, Dominican, and Caucasian mothers and newborns.

    PubMed

    Wang, Shuang; Chanock, Stephen; Tang, Deliang; Li, Zhigang; Jedrychowski, Wieslaw; Perera, Frederica P

    2008-02-01

    Polycyclic aromatic hydrocarbons (PAH) are widespread pollutants commonly found in air, food, and drinking water. Benzo[a]pyrene is a well-studied representative PAH found in air from fossil fuel combustion and a transplacental carcinogen experimentally. PAHs bind covalently to DNA to form DNA adducts, an indicator of DNA damage, and an informative biomarker of potential cancer risk. Associations between PAH-DNA adduct levels and both cancer risk and developmental deficits have been seen in previous experimental and epidemiologic studies. Several genes have been shown to play an important role in the metabolic activation or detoxification of PAHs, including the cytochrome P450 genes CYP1A1 and CYP1B1 and the glutathione S-transferase (GST) genes GSTM1, and GSTT2. Genetic variation in these genes could influence susceptibility to adverse effects of PAHs in polluted air. Here, we have explored interactions between prenatal PAH exposure and 17 polymorphisms in these genes (rs2198843, rs1456432, rs4646903, rs4646421, rs2606345, rs7495708, rs2472299, rs162549, rs1056837, rs1056836, rs162560, rs10012, rs2617266, rs2719, rs1622002, rs140194, and gene deletion GSTM1-02) and haplotypes on PAH-DNA adducts in cord blood of 547 newborns and in maternal blood of 806 mothers from three different self-described ethnic groups: African Americans, Dominicans, and Caucasians. PAHs were measured by personal air monitoring of mothers during pregnancy. Significant interactions (p < 0.05) were observed between certain genetic polymorphisms and CYP1A1 haplotype and PAHs in mothers and their newborns in the three ethnic groups. However, with our limited sample size, the current findings are suggestive only, warranting further study.

  17. Quantitation of 4,4′-methylene diphenyl diisocyanate human serum albumin adducts

    PubMed Central

    Luna, Leah G.; Green, Brett J.; Zhang, Fagen; Arnold, Scott M.; Siegel, Paul D.; Bartels, Michael J.

    2016-01-01

    4,4′-Methylene diphenyl diisocyanate (herein 4,4′-MDI) is used in the production of polyurethane foams, elastomers, coatings, adhesives and the like for a wide range of commercial products. Occupational exposure to MDI levels above current airborne exposure limits can elicit immune mediated hypersensitivity reactions such as occupational asthma in sensitive individuals. To accurately determine exposure, there has been increasing interest in developing analytical methods to measure internal biomarkers of exposure to MDI. Previous investigators have reported methodologies for measuring MDI diamine metabolites and MDI-Lysine (4,4′-MDI-Lys) adducts. The purpose of this study was to develop and validate an ultra performance liquid chromatography isotope dilution tandem mass spectrometry (UPLC-ID/MS/MS) quantitation method via a signature peptide approach to enable biomonitoring of 4,4′-MDI adducted to human serum albumin (HSA) in plasma. A murine, anti-4,4′-MDI monoclonal IgM antibody was bound to magnetic beads and utilized for enrichment of the MDI adducted HSA. Following enrichment, trypsin digestion was performed to generate the expected 414 site (primary site of adduction) 4,4′-MDI-adducted HSA signature peptide that was quantified by UPLC-ID/MS/MS. An Agilent 6530 UPLC/quadrupole time of flight MS (QTOF) system was utilized for intact adducted protein analysis and an Agilent 6490 UPLC/MS/MS system operated in multiple reaction monitoring (MRM) mode was utilized for quantification of the adducted signature peptide biomarker both for in chemico and worker serum samples. Worker serum samples were initially screened utilizing the previously developed 4,4′-MDI-Lys amino acid method and results showed that 12 samples were identified as quantifiable for 4,4′-MDI-Lys adducts. The signature peptide adduct approach was applied to the 12 worker samples identified as quantifiable for 4,4′-MDI-Lys adducts. Results indicated no positive results were obtained

  18. Detection and quantitation of benzo(a)pyrene-derived DNA adducts in mouse liver by liquid chromatography - tandem mass spectrometry: comparison with P-32-postlabeling

    SciTech Connect

    Singh, R.; Gaskell, M.; Le Pla, R.C.; Kaur, B.; Azim-Araghi, A.; Roach, J.; Koukouves, G.; Souliotis, V.L.; Kyrtopoulos, S.A.; Farmer, P.B.

    2006-06-19

    The polycyclic aromatic hydrocarbon, benzo(a)pyrene (B(a)P) is a proven animal carcinogen that is potentially carcinogenic to humans. B( a)P is an ubiquitous environmental pollutant and is also present in tobacco smoke, coal tar, automobile exhaust emissions, and charred food. A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method using electrospray ionization and selected reaction monitoring (SRM) has been developed for the detection of 10-(deoxyguanosin-N{sub 2}-yl)-7,8,9-trihydroxy-7,8,9,10- tetrahydrobenzo(a)pyrene (B(a)PDE-N{sub 2}dG) adducts formed in DNA following the metabolic activation of B(a)P to benzo(a) pyrene-7,8-dihydrodiol-9,10-epoxide (B(a)PDE).

  19. DNA adducts in marine mussel and fresh water fishes living in polluted and unpolluted environments

    SciTech Connect

    Kurelec, B.; Checko, M.; Krca, S.; Garg, A.; Gupta, R.C. Baylor College of Medicine, Houston, TX )

    1988-09-01

    {sup 32}P-postlabeling analysis of DNA adducts in the digestive gland of marine mussel Mytilus galloprovincialis from polluted and unpolluted sites near Rovinj, Northern Adriatic, revealed that majority of adducts are caused by natural environmental factors rather than by man-made chemicals. The only pollutant-specific adducts were observed in a mussel exposed to seawater experimentally polluted with aminofluorene, and in a population of mussel living at a site heavily polluted with a waste waters of an oil refinery. Fresh water fish species Leuciscus cephalus, Barbus barbus, Abramis brama and Rutilus pigus virgo living in a polluted Sava River, Yugoslavia, or in its unpolluted tributary Korana River, have induced in their livers qualitatively identical and quantitatively similar DNA adducts. These DNA adducts had a species-specific patterns and their appearance was seasonally-dependent.

  20. MRN, CtIP, and BRCA1 mediate repair of topoisomerase II-DNA adducts.

    PubMed

    Aparicio, Tomas; Baer, Richard; Gottesman, Max; Gautier, Jean

    2016-02-15

    Repair of DNA double-strand breaks (DSBs) with complex ends poses a special challenge, as additional processing is required before DNA ligation. For example, protein-DNA adducts must be removed to allow repair by either nonhomologous end joining or homology-directed repair. Here, we investigated the processing of topoisomerase II (Top2)-DNA adducts induced by treatment with the chemotherapeutic agent etoposide. Through biochemical analysis in Xenopus laevis egg extracts, we establish that the MRN (Mre11, Rad50, and Nbs1) complex, CtIP, and BRCA1 are required for both the removal of Top2-DNA adducts and the subsequent resection of Top2-adducted DSB ends. Moreover, the interaction between CtIP and BRCA1, although dispensable for resection of endonuclease-generated DSB ends, is required for resection of Top2-adducted DSBs, as well as for cellular resistance to etoposide during genomic DNA replication.

  1. Drug-Protein Adducts: Chemistry, Mechanisms of Toxicity, and Methods of Characterization.

    PubMed

    Gan, Jinping; Zhang, Haiying; Humphreys, W Griffith

    2016-12-19

    The formation of drug-protein adducts is considered an important feature in the pharmacological and toxicological profiles of many drugs. Mechanistic insights into the role of specific protein adduct formation in pharmacology and toxicology remain scarce, partly due to the availability of tools to identify and characterize the specific protein adducts, and partly due to the scarcity of relevant in vitro and in vivo predictive models. This review serves to provide a review on the current state of science on the chemistry, toxicology, and methods of detection and characterization of drug-protein adducts and to offer some perspective on the future directions of research into the role of protein adducts in drug effects and toxicity.

  2. Liquid chromatography-thermospray mass spectrometry of DNA adducts formed with mitomycin C, porfiromycin and thiotepa.

    PubMed

    Musser, S M; Pan, S S; Callery, P S

    1989-07-14

    High-performance liquid chromatography (HPLC) and thermospray mass spectrometry were combined for the analysis of DNA adducts formed from the interaction of the anticancer drugs mitomycin C, porfiromycin and thiotepa with calf thymus DNA. The adducts formed from reaction of mitomycin C and porfiromycin with DNA were separated from unmodified nucleosides by HPLC on a C18 column and identified by thermospray mass spectrometry. Thiotepa DNA adducts readily depurinated from DNA and were chromatographed and identified by thermospray liquid chromatography-mass spectrometry as the modified bases without the ribose moiety attached. The utility of thermospray mass spectrometry for the identification of microgram quantities of nucleoside adducts and depurinated base adducts of these anticancer drugs was demonstrated.

  3. Modulations of benzo[a]pyrene-induced DNA adduct, cyclin D1 and PCNA in oral tissue by 1,4-phenylenebis(methylene)selenocyanate

    SciTech Connect

    Chen, Kun-Ming; Sacks, Peter G.; Spratt, Thomas E.; Lin, Jyh-Ming; Boyiri, Telih; Schwartz, Joel; Richie, John P.; Calcagnotto, Ana; Das, Arunangshu; Bortner, James; Zhao, Zonglin; Amin, Shantu; Guttenplan, Joseph; El-Bayoumy, Karam

    2009-05-22

    Tobacco smoking is an important cause of human oral squamous cell carcinoma (SCC). Tobacco smoke contains multiple carcinogens include polycyclic aromatic hydrocarbons typified by benzo[a]pyrene (B[a]P). Surgery is the conventional treatment approach for SCC, but it remains imperfect. However, chemoprevention is a plausible strategy and we had previously demonstrated that 1,4-phenylenebis(methylene)selenocyanate (p-XSC) significantly inhibited tongue tumors-induced by the synthetic 4-nitroquinoline-N-oxide (not present in tobacco smoke). In this study, we demonstrated that p-XSC is capable of inhibiting B[a]P-DNA adduct formation, cell proliferation, cyclin D1 expression in human oral cells in vitro. In addition, we showed that dietary p-XSC inhibits B[a]P-DNA adduct formation, cell proliferation and cyclin D1 protein expression in the mouse tongue in vivo. The results of this study are encouraging to further evaluate the chemopreventive efficacy of p-XSC initially against B[a]P-induced tongue tumors in mice and ultimately in the clinic.

  4. Identification of S-3-(hexanal)-glutathione and its bisulfite adduct in grape juice from Vitis vinifera L. cv. Sauvignon blanc as new potential precursors of 3SH.

    PubMed

    Thibon, Cécile; Böcker, Caroline; Shinkaruk, Svitlana; Moine, Virginie; Darriet, Philippe; Dubourdieu, Denis

    2016-05-15

    Two main precursors (S-3-(hexan-1-ol)-l-cysteine and S-3-(hexan-1-ol)-l-glutathione) of 3-sulfanylhexanol (3SH, formerly named 3-mercaptohexanol) have been identified so far in grape juice but a correlation between precursor concentrations in grape juices and 3SH concentrations in wines is not always observed. This suggests that there may be other compounds associated with the aromatic potential. In this work, S-3-(hexanal)-glutathione (Glut-3SH-Al) and its bisulfite (Glut-3SH-SO3) adduct were identified in Sauvignon blanc grape juice by liquid chromatography coupled to Fourier transform mass spectrometry experiments. A partial purification of the compounds was carried out by Medium Pressure Liquid Chromatography (MPLC) on the reverse phase using 5L of grape juice. The addition of synthetized Glut-3SH-Al and Glut-3SH-SO3 in the synthetic medium induced a significant release of 3SH after fermentation. Moreover, we demonstrate that Glut-3SH-Al and its bisulfite adduct are present in grape juice and could be considered as new direct 3SH precursors with molar conversion yields close to 0.4%. Copyright © 2016. Published by Elsevier Ltd.

  5. Polybenzimidazoles Via Aromatic Nucleophilic Displacement

    NASA Technical Reports Server (NTRS)

    Connell, John W.; Hergenrother, Paul M.; Smith, Joseph G.

    1994-01-01

    Soluble polybenzimidazoles (PBI's) synthesized by nucleophilic displacement reaction of di(hydroxyphenyl)-benzimidazole monomers with activated aromatic difluoride compounds in presence of anhydrous potassium carbonate. These polymers exhibit good thermal, thermo-oxidative, and chemical stability, and high mechanical properties. Using benzimidazole monomers, more economical, and new PBI's processed more easily than commercial PBI, without loss of desirable physical properties.

  6. Polybenzimidazoles Via Aromatic Nucleophilic Displacement

    NASA Technical Reports Server (NTRS)

    Connell, John W.; Hergenrother, Paul M.; Smith, Joseph G.

    1994-01-01

    Soluble polybenzimidazoles (PBI's) synthesized by nucleophilic displacement reaction of di(hydroxyphenyl)-benzimidazole monomers with activated aromatic difluoride compounds in presence of anhydrous potassium carbonate. These polymers exhibit good thermal, thermo-oxidative, and chemical stability, and high mechanical properties. Using benzimidazole monomers, more economical, and new PBI's processed more easily than commercial PBI, without loss of desirable physical properties.

  7. Binuclear Phthalocyanines with Aromatic Bridges

    DTIC Science & Technology

    1989-03-01

    successful. (Scheme 2) Synthesis of Binuclear Phthalocyanines Covalently Bridged by Anthracene The coupling reaction of aromatic halides using elemental...available (16), it Is not active enough to undergo the desired cross coupling reaction . Less electropositive arylzinc derivatives can tolerate various electro...philic functional groups such as nitriles and esters (17). These organo- metallic reagents readily undergo cross coupling reaction with aryl halides

  8. Tough, soluble, aromatic, thermoplastic copolyimides

    NASA Technical Reports Server (NTRS)

    Bryant, Robert G. (Inventor)

    1994-01-01

    Tough, soluble, aromatic, thermoplastic copolyimides were prepared by reacting 4,4'-oxydiphthalic anhydride, 3,4,3',4'-biphenyltetracarboxylic dianhydride and 3,4'-oxydianiline. These copolyimides were found to be soluble in common amide solvents such as acetamide, Nmethylpyrrolidinone, and dimethylformamide allowing them to be applied as the fully imidized copolymer and to be used to prepare a wide range of articles.

  9. The Aromaticity of Pericyclic Reaction Transition States

    ERIC Educational Resources Information Center

    Rzepa, Henry S.

    2007-01-01

    An approach is presented that starts from two fundamental concepts in organic chemistry, chirality and aromaticity, and combines them into a simple rule for stating selection rules for pericyclic reactions in terms of achiral Huckel-aromatic and chiral Mobius-aromatic transition states. This is illustrated using an example that leads to apparent…

  10. Line narrowing spectroscopic studies of DNA-carcinogen adducts and DNA-dye complexes

    SciTech Connect

    Suh, Myungkoo

    1995-12-06

    Laser-induced fluorescence line narrowing and non-line narrowing spectroscopic methods were applied to conformational studies of stable DNA adducts of the 7β, 8α-dihydoxy-9α, l0α-epoxy-7,8,9, 10-tetrahydrobenzo[α]pyrene (anti-BPDE). Stereochemically distinct (+)-trans-, (-)-trans-, (+)-cis- and (-)-cis adducts of anti-BPDE bound to exocyclic amino group of the central guanine in an 11-mer oligonucleotide, exist in a mixture of conformations in frozen aqueous buffer matrices. The (+)-trans adduct adopts primarily an external conformation with a smaller fraction ( ~25 %) exists in a partially base-stacked conformation. Both cis adducts were found to be intercalated with significant π-π stacking interactions between the pyrenyl residues and the bases. Conformations of the trans-adduct of (+)-anti -BPDE in 11-mer oligonucleotides were studied as a function of flanking bases. In single stranded form the adduct at G2 or G3 (5 ft-flanking, base guanine) adopts a conformation with strong, interaction with the bases. In contrast, the adduct with a 5ft-flanking, thymine exists in a primarily helixexternal conformation. Similar differences were observed in the double stranded oligonucleotides. The nature of the 3ft-flanking base has little influence on the conformational equilibrium of the (+)-trans-anti BPDE-dG adduct. The formation and repair of BPDE-N2-dG in DNA isolated from the skin of mice treated topically with benzo[α]pyrene (BP) was studied. Low-temperature fluorescence spectroscopy of the intact DNA identified the major adduct as (+)-trans-anti-BPDE-N-dG, and the minor adduct fraction consisted mainly of (+)-cis-anti-BPDE-N2-dG.

  11. White blood cell DNA adducts in a cohort of asthmatic children exposed to environmental tobacco smoke.

    PubMed

    Wilson, Stephen E; Talaska, Glenn; Kahn, Robert S; Schumann, Brenda; Khoury, Jane; Leonard, Anthony C; Lanphear, Bruce P

    2011-01-01

    Exposure to environmental tobacco smoke (ETS) leads to molecular damage in the form of DNA adducts. While lung cancer risk is higher among African Americans compared to White Americans, a few studies have tested for racial differences in DNA adducts among children exposed to ETS. The purpose of this study was to test whether African American children have higher DNA adducts levels compared to White children adjusted for ETS exposure. Data and biologic specimens were drawn from an existing cohort of 212 asthmatic children. These subjects participated in a 12-month ETS-reduction trial that employed HEPA air cleaners with active filter cartridges and sham filter cartridges. White blood cell (WBC) DNA was analyzed for DNA adducts using (32)P-postlabeling. We assessed ETS exposure using a validated air nicotine dosimeter. We determined the independent relationship between African American race and DNA adduct levels adjusted for ETS exposure and air cleaner use. The mean age of the subjects was 8.4 years; 55% were African American. There was no difference in DNA adduct levels between African American and White children (11.8 vs. 11.2 adducts per 10(9) nucleotides, p = 0.86), despite slightly higher levels of air nicotine exposure (3.4 vs. 2.2 μg/m(3), p = 0.14). African American children used their air cleaners less often than White children. We found that the best predictor of DNA adduct levels was the duration of air cleaner use (r = -0.133, p = 0.056). This association was independent of cartridge type. We did not see differences in adduct levels by race even after accounting for the level of ETS exposure. However, there was a marginal inverse association between air cleaner use and adducts. Additional research is required to understand this phenomenon.

  12. White blood cell DNA adducts in a cohort of asthmatic children exposed to environmental tobacco smoke

    PubMed Central

    Talaska, Glenn; Kahn, Robert S.; Schumann, Brenda; Khoury, Jane; Leonard, Anthony C.; Lanphear, Bruce P.

    2010-01-01

    Purpose Exposure to environmental tobacco smoke (ETS) leads to molecular damage in the form of DNA adducts. While lung cancer risk is higher among African Americans compared to White Americans, a few studies have tested for racial differences in DNA adducts among children exposed to ETS. The purpose of this study was to test whether African American children have higher DNA adducts levels compared to White children adjusted for ETS exposure. Methods Data and biologic specimens were drawn from an existing cohort of 212 asthmatic children. These subjects participated in a 12-month ETS-reduction trial that employed HEPA air cleaners with active filter cartridges and sham filter cartridges. White blood cell (WBC) DNA was analyzed for DNA adducts using 32P-postlabeling. We assessed ETS exposure using a validated air nicotine dosimeter. We determined the independent relationship between African American race and DNA adduct levels adjusted for ETS exposure and air cleaner use. Results The mean age of the subjects was 8.4 years; 55% were African American. There was no difference in DNA adduct levels between African American and White children (11.8 vs. 11.2 adducts per 109 nucleotides, p = 0.86), despite slightly higher levels of air nicotine exposure (3.4 vs. 2.2 μg/m3, p = 0.14). African American children used their air cleaners less often than White children. We found that the best predictor of DNA adduct levels was the duration of air cleaner use (r = −0.133, p = 0.056). This association was independent of cartridge type. Conclusions We did not see differences in adduct levels by race even after accounting for the level of ETS exposure. However, there was a marginal inverse association between air cleaner use and adducts. Additional research is required to understand this phenomenon. PMID:20336464

  13. Accurate characterization of carcinogenic DNA adducts using MALDI tandem time-of-flight mass spectrometry

    NASA Astrophysics Data System (ADS)

    Barnes, Charles A.; Chiu, Norman H. L.

    2009-01-01

    Many chemical carcinogens and their in vivo activated metabolites react readily with genomic DNA, and form covalently bound carcinogen-DNA adducts. Clinically, carcinogen-DNA adducts have been linked to various cancer diseases. Among the current methods for DNA adduct analysis, mass spectroscopic method allows the direct measurement of unlabeled DNA adducts. The goal of this study is to explore the use of matrix-assisted laser desorption/ionization tandem time-of-flight mass spectrometry (MALDI-TOF/TOF MS) to determine the identity of carcinogen-DNA adducts. Two of the known carcinogenic DNA adducts, namely N-(2'-deoxyguanosin-8-yl)-2-amino-1-methyl-6-phenyl-imidazo [4,5-b] pyridine (dG-C8-PhIP) and N-(2'-deoxyguanosin-8yl)-4-aminobiphenyl (dG-C8-ABP), were selected as our models. In MALDI-TOF MS measurements, the small matrix ion and its cluster ions did not interfere with the measurements of both selected dG adducts. To achieve a higher accuracy for the characterization of selected dG adducts, 1 keV collision energy in MALDI-TOF/TOF MS/MS was used to measure the adducts. In comparison to other MS/MS techniques with lower collision energies, more extensive precursor ion dissociations were observed. The detection of the corresponding fragment ions allowed the identities of guanine, PhIP or ABP, and the position of adduction to be confirmed. Some of the fragment ions of dG-C8-PhIP have not been reported by other MS/MS techniques.

  14. Development of an immunochemical detection method for atrazine-induced albumin adducts.

    PubMed

    Dooley, Greg P; Hanneman, William H; Carbone, David L; Legare, Marie E; Andersen, Melvin E; Tessari, John D

    2007-07-01

    Atrazine (2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine) is one of the most commonly used herbicides in the United States. Exposures in rodent models have led to a host of biological effects, most notably the suppression of luteinizing hormone surge. Previously, we have reported that diaminochlorotriazine (DACT), an atrazine metabolite, forms a covalent adduct with rat hemoglobin at Cys-125. In the present study, we investigated the formation of a similar covalent adduct at Cys-34 of rat and human albumins following atrazine exposure using MALDI-TOF/TOF MS and adduct-specific immunochemical detection. Using mass spectrometry, a covalent adduct with a mass of 110 Da was located on Cys-34 of albumin from rats exposed to 20, 50, 100, and 200 mg/kg atrazine as well as rat and human albumins exposed in vitro to 90 microg/mL DACT. On the basis of the formation of the adduct in vitro, the adduct structure is a dechlorinated diaminochlorotriazine. To further study this unique protein adduction, we collaborated with Strategic Biosolutions Inc. to generate a polyclonal antibody specific for the DACT adduct and report its use for immunochemical detection. We detected adduct formation in purified serum albumin samples from rats given 5, 10, 20, 50, 100, and 200 mg/kg atrazine as well as rat and human albumins exposed in vitro to 90 microg/mL DACT by using immunochemical analysis. No adducts were detected in control animals or in the in vitro controls using our immunochemical detection method. In summary, these data report the development of a novel immunochemical detection system that could provide a rapid screening methodology for the detection of atrazine in exposed human populations.

  15. ON BENZO[A]PYRENE DERIVED DNA ADDUCTS FORMED IN LUNG TISSUE OF MICE

    EPA Science Inventory

    On Benzo [a] pyrene Derived DNA Adducts Formed in Lung Tissue of Mice
    The previously identified major DNA adducts of benzo[a]pyrene (BP) in vitro and in vivo are the stable and unstable adducts formed by reaction of the bay-region diol epoxide of BP (BPDE) and BP radical catio...

  16. ON BENZO[A]PYRENE DERIVED DNA ADDUCTS FORMED IN LUNG TISSUE OF MICE

    EPA Science Inventory

    On Benzo [a] pyrene Derived DNA Adducts Formed in Lung Tissue of Mice
    The previously identified major DNA adducts of benzo[a]pyrene (BP) in vitro and in vivo are the stable and unstable adducts formed by reaction of the bay-region diol epoxide of BP (BPDE) and BP radical catio...

  17. The formation of covalent adducts between benzo(a)pyrenediol epoxide and RNA: Structural analysis by mass spectrometry

    SciTech Connect

    Yamamoto, J.; Subramaniam, R.; Wolfe, A.R.; Meehan, T. )

    1990-04-24

    Racemic 7-r,8-t-dihydroxy-9-t,10-t-epoxy-7,8,9,10-tetrahydrobenzo(a)pyrene was reacted with yeast RNA. Modified nucleosides were isolated and resolved by high-performance liquid chromatography; nine adduct peaks were collected for analysis. The bases in these adducts were identified by comparing their retention time with those of adducts from poly(G), poly(A), and poly(C). These samples gave two major and two minor Guo adducts, four major Ado adducts, and at least four Cyd adducts. The relative efficiencies of adduct formation with the polyribionucleotides were poly(G) > yeast RNA > poly(A) > poly(C). Fluorescence measurements show that emission from Guo adducts is strongly quenched relative to that from Ado adducts. Liquid secondary ion mass spectrometry (LSIMS) of underivatized samples and electron-impact mass spectrometry (EIMS) of permethyl derivatives were used to confirm the base identities and establish the alkylation sites of the RNA adducts. Unique nitrogen-containing hydrocarbon fragments that were observed with all samples by EIMS establish that in each adduct analyzed the C-10 position of the hydrocarbon is linked to the exocyclic amino group of the base. This suggested that the multiple adducts formed with each base are diastereomers derived from cis/trans epoxide ring opening of the (+) and (-) enantiomers of the carcinogen. Major fragmentation pathways resulted in formation of nucleoside, base, ribose, hydrocarbon, and base-hydrocarbon ions.

  18. Polycyclic aromatic hydrocarbon (PAH) ecotoxicology in marine ecosystems.

    PubMed

    Hylland, Ketil

    2006-01-08

    Low levels of oil and hence polycyclic aromatic hydrocarbons (PAHs) are naturally present in the marine environment, although levels have increased significantly following human extraction and use of oil and gas. Other major anthropogenic sources of PAHs include smelters, the use of fossil fuels in general, and various methods of waste disposal, especially incineration. There are two major sources for PAHs to marine ecosystems in Norway: the inshore smelter industry, and offshore oil and gas production activities. A distinction is generally made between petrogenic (oil-derived) and pyrogenic (combustion-derived) PAHs. Although petrogenic PAHs appear to be bioavailable to a large extent, pyrogenic PAHs are often associated with soot particles and less available for uptake into organisms. There is extensive evidence linking sediment-associated PAHs to induction of phase-I enzymes, development of DNA adducts, and eventually neoplastic lesions in fish. Most studies have focused on high-molecular-weight, carcinogenic PAHs such as benzo[a]pyrene. It is less clear how two- and three-ring PAHs affect fish, and there is even experimental evidence to indicate that these chemicals may inhibit some components of the phase I system rather than produce induction. There is a need for increased research efforts to clarify biological effects of two- and three-ring PAHs, PAH mixtures, and adaptation processes in marine ecosystems.

  19. Role of radical cations in aromatic hydrocarbon carcinogenesis.

    PubMed Central

    Cavalieri, E; Rogan, E

    1985-01-01

    Carcinogenic activation of polycyclic aromatic hydrocarbons (PAH) involves two main pathways: one-electron oxidation and monooxygenation. One-electron oxidation produces PAH radical cations, which can react with cellular nucleophiles. Results from biochemical and biological experiments indicate that only PAH with ionization potentials below ca. 7.35 eV can be metabolically activated by one-electron oxidation. In addition, the radical cations of carcinogenic PAH must have relatively high charge localization to react effectively with macromolecules in target cells. Metabolic formation of PAH quinones proceeds through radical cation intermediates. Binding of benzo[a]pyrene (BP) to mouse skin DNA occurs predominantly at C-6, the position of highest charge localization in the BP radical cation, and binding of 6-methyl BP to DNA in mouse skin yields a major adduct with the 6-methyl group bound to the 2-amino group of deoxyguanosine. Studies of carcinogenicity by direct application of PAH to rat mammary gland indicate that only PAH with ionization potentials low enough for activation by one-electron oxidation produce tumors in this target tissue. These constitute some of the results which provide evidence for the involvement of one-electron oxidation in PAH carcinogenesis. PMID:3830701

  20. IDENTIFICATION AND QUANTITATION OF BENZO[A]PYRENE DERIVED DNA ADDUCTS FORMED AT LOW ADDUCTION LEVEL IN MICE LUNG TISSUE

    EPA Science Inventory

    The two major metabolic pathways of benzo[a]pyrene (BP), as well as other polycyclic aromatic hydrocarbons, that allow for the induction of DNA lesions are monooxygenation that results in diol epoxides (BPDE), and one-electron oxidation that yields a BP radical cation. The DNA ad...