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De Palma G, Poli D, Manini P, Andreoli R, Mozzoni P, Apostoli P, Mutti A. Biomarkers of exposure to aromatic hydrocarbons and methyltert-butyl ether in petrol station workers. Biomarkers 2012; 17:343-51. [DOI: 10.3109/1354750x.2012.672459] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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52
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Carugno M, Pesatori AC, Dioni L, Hoxha M, Bollati V, Albetti B, Byun HM, Bonzini M, Fustinoni S, Cocco P, Satta G, Zucca M, Merlo DF, Cipolla M, Bertazzi PA, Baccarelli A. Increased mitochondrial DNA copy number in occupations associated with low-dose benzene exposure. ENVIRONMENTAL HEALTH PERSPECTIVES 2012; 120:210-5. [PMID: 22005026 PMCID: PMC3279451 DOI: 10.1289/ehp.1103979] [Citation(s) in RCA: 89] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2011] [Accepted: 10/17/2011] [Indexed: 05/07/2023]
Abstract
BACKGROUND Benzene is an established leukemogen at high exposure levels. Although low-level benzene exposure is widespread and may induce oxidative damage, no mechanistic biomarkers are available to detect biological dysfunction at low doses. OBJECTIVES Our goals were to determine in a large multicenter cross-sectional study whether low-level benzene is associated with increased blood mitochondrial DNA copy number (mtDNAcn, a biological oxidative response to mitochondrial DNA damage and dysfunction) and to explore potential links between mtDNAcn and leukemia-related epigenetic markers. METHODS We measured blood relative mtDNAcn by real-time polymerase chain reaction in 341 individuals selected from various occupational groups with low-level benzene exposures (> 100 times lower than the Occupational Safety and Health Administration/European Union standards) and 178 referents from three Italian cities (Genoa, Milan, Cagliari). RESULTS In each city, benzene-exposed participants showed higher mtDNAcn than referents: mtDNAcn was 0.90 relative units in Genoa bus drivers and 0.75 in referents (p = 0.019); 0.90 in Milan gas station attendants, 1.10 in police officers, and 0.75 in referents (p-trend = 0.008); 1.63 in Cagliari petrochemical plant workers, 1.25 in referents close to the plant, and 0.90 in referents farther from the plant (p-trend = 0.046). Using covariate-adjusted regression models, we estimated that an interquartile range increase in personal airborne benzene was associated with percent increases in mtDNAcn equal to 10.5% in Genoa (p = 0.014), 8.2% (p = 0.008) in Milan, 7.5% in Cagliari (p = 0.22), and 10.3% in all cities combined (p < 0.001). Using methylation data available for the Milan participants, we found that mtDNAcn was associated with LINE-1 hypomethylation (-2.41%; p = 0.007) and p15 hypermethylation (+15.95%, p = 0.008). CONCLUSIONS Blood MtDNAcn was increased in persons exposed to low benzene levels, potentially reflecting mitochondrial DNA damage and dysfunction.
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MESH Headings
- Adult
- Air Pollutants, Occupational/analysis
- Air Pollutants, Occupational/toxicity
- Benzene/analysis
- Benzene/toxicity
- Biomarkers/blood
- Cities/epidemiology
- Cross-Sectional Studies
- Cyclin-Dependent Kinase Inhibitor p15/blood
- Cyclin-Dependent Kinase Inhibitor p15/drug effects
- DNA Damage/drug effects
- DNA Methylation/drug effects
- DNA, Mitochondrial/blood
- Dose-Response Relationship, Drug
- Female
- Gene Dosage/drug effects
- Humans
- Italy/epidemiology
- Leukemia, Myeloid, Acute/blood
- Leukemia, Myeloid, Acute/epidemiology
- Leukemia, Myeloid, Acute/etiology
- Long Interspersed Nucleotide Elements
- Male
- Middle Aged
- Multivariate Analysis
- Occupational Exposure
- Real-Time Polymerase Chain Reaction
- Regression Analysis
- Young Adult
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Affiliation(s)
- Michele Carugno
- Department of Occupational and Environmental Health, Università degli Studi di Milano, Milan, Italy.
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Fustinoni S, Campo L, Satta G, Campagna M, Ibba A, Tocco MG, Atzeri S, Avataneo G, Flore C, Meloni M, Bertazzi PA, Cocco P. Environmental and lifestyle factors affect benzene uptake biomonitoring of residents near a petrochemical plant. ENVIRONMENT INTERNATIONAL 2012; 39:2-7. [PMID: 22208737 DOI: 10.1016/j.envint.2011.09.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2011] [Revised: 08/12/2011] [Accepted: 09/01/2011] [Indexed: 05/31/2023]
Abstract
BACKGROUND We monitored urinary benzene excretion to examine factors affecting benzene uptake in a sample of the general population living near a petrochemical plant. METHODS Our study population included 143 subjects: 33 petrochemical plant workers (W) with low level occupational benzene exposure; 30 residents in a small town 2 km from the plant (2kmR); 26 residents in a second small town located 2 to 4 km from the plant (4kmR); and 54 urban residents 25km from the plant (25kmR). Exposure to benzene was evaluated by personal air sampling during one work-shift for the W group, and from 8.00 to 20:00 for general population subgroups, and by urinary benzene (BEN-U). RESULTS Median airborne benzene exposure was 25, 9, 7 and 6 μg/m(3) benzene among the W, 2kmR, 4kmR, and 25kmR subgroups, respectively; the highest level was found among the workers, while there was no significant difference among the other groups. Median BEN-U was 2 to 14-fold higher in smokers compared to non-smokers; among non-smokers BEN-U was the highest in W (median 236 ng/L), and lower in the 2kmR (48 ng/L) and 4kmR (63 ng/L) subgroups than in the 25kmR (120 ng/L) subgroup. A multiple linear regression analysis, explaining up to 73% of BEN-U variability, confirmed that active smoking and airborne benzene most strongly affected BEN-U. Among the non-smoking, non-occupationally exposed study subjects, a positive association was found between BEN-U and the distance of residence from the plant. This association was explained by increased exposure to urban traffic emissions in the study group residing at a greater distance from the plant. Environmental tobacco smoke had a marginally positive role. CONCLUSION Among factors affecting benzene uptake in non-occupationally exposed individuals, urban residence contributes to benzene exposure more than residing in close proximity to a petrochemical plant.
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Affiliation(s)
- Silvia Fustinoni
- Department of Occupational and Environmental Medicine, University of Milan and Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Via S. Barnaba, 8-20122 Milan, Italy.
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Schulte PA, Hauser JE. The use of biomarkers in occupational health research, practice, and policy. Toxicol Lett 2011; 213:91-9. [PMID: 21477643 DOI: 10.1016/j.toxlet.2011.03.027] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2011] [Accepted: 03/25/2011] [Indexed: 11/17/2022]
Abstract
Biomarkers are potentially useful tools for occupational health and safety research, practice, and policy. However, the full realization of this potential has not been achieved. In this paper, the progress made in these three usage areas is reviewed to identify what efforts can be taken to realize the full promise of biomarkers. Biomarker uses are described by a diverse taxonomy that builds on the categories of exposure, effect and susceptibility, and the continuum between exposure and disease prognosis. The most significant uses of biomarkers in occupational health have been in biological monitoring of workers. Other important uses have been in enhancing research and assessing mechanisms of action of occupational toxicants at low exposures. Seven critical areas will influence the extent to which the potential of biomarkers in occupational health and safety is realized. These include: (1) adequate investment in validation; (2) obtaining international agreement on exposure guidelines; (3) exploring the utility of biomarkers in regulation; (4) applying biomarkers to critical occupational safety and health questions; (5) developing the exposome; (6) utilizing biomarkers to address emerging occupational health issues; and (7) continuing to address the ethical and social justice issues related to biomarkers. Overall, if biomarkers are to make a major contribution to occupational health and safety then a more holistic approach to bringing them from the laboratory to practice will be needed.
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Affiliation(s)
- P A Schulte
- National Institute for Occupational Safety and Health, 4676 Columbia Parkway, Cincinnati, OH 45226, USA.
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Fustinoni S, Campo L, Mercadante R, Consonni D, Mielzynska D, Bertazzi PA. A quantitative approach to evaluate urinary benzene and S-phenylmercapturic acid as biomarkers of low benzene exposure. Biomarkers 2011; 16:334-45. [DOI: 10.3109/1354750x.2011.561499] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Silvia Fustinoni
- University of Milan, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Department of Occupational and Environmental Medicine, Milano, Italy
| | - Laura Campo
- University of Milan, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Department of Occupational and Environmental Medicine, Milano, Italy
| | - Rosa Mercadante
- University of Milan, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Department of Occupational and Environmental Medicine, Milano, Italy
| | - Dario Consonni
- University of Milan, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Department of Occupational and Environmental Medicine, Milano, Italy
| | | | - Pier Alberto Bertazzi
- University of Milan, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Department of Occupational and Environmental Medicine, Milano, Italy
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Mansi A, Bruni R, Capone P, Paci E, Pigini D, Simeoni C, Gnerre R, Papacchini M, Tranfo G. Low occupational exposure to benzene in a petrochemical plant: modulating effect of genetic polymorphisms and smoking habit on the urinary t,t-MA/SPMA ratio. Toxicol Lett 2011; 213:57-62. [PMID: 21300142 DOI: 10.1016/j.toxlet.2011.02.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2010] [Accepted: 02/01/2011] [Indexed: 10/18/2022]
Abstract
The identification of reliable biomarkers is critical for the assessment of occupational exposure of benzene: S-phenylmercapturic acid (SPMA) and trans,trans-muconic acid (t,t-MA) are the most currently used. t,t-MA is an open-ring metabolite, but it is also a metabolite of the food preservative sorbic acid, while SPMA is formed by conjugation with glutathione, and several studies suggested that the genetic polymorphism of glutathione S-transferases modulates its production. This study compared the ability of these metabolites to assess the benzene exposure in a big group of petrochemical workers. Furthermore, investigated how genetic polymorphism of glutathione S-transferase theta 1 (GSTT1), glutathione S-transferase mu 1 (GSTM1), glutathione S-transferase pi 1 (GSTP1) and smoking habits, may influence their excretion. Results showed that occupational exposure to benzene was negligible compared to that from smoking and confirmed the modulating effect of the genetic polymorphism of GSTT1 on the urinary excretion of SPMA, but not of t, t-MA, even at very low levels of benzene exposure. The same effect was found for GSTM1, but only for smokers. The t,t-MA/SPMA ratio was not a constant value and resulted to be higher than the corresponding Biological Exposure Index (BEI) ratio, which is currently equal to 20. Higher values of metabolite have been associated with the GSTT1 or GSTM1 null genotype and these are responsible for increase health risk. We suggest that this ratio could be used as a marker of individual susceptibility for subjects with benzene exposure.
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Affiliation(s)
- Antonella Mansi
- INAIL Research, Department of Occupational Hygiene, Via di Fontana Candida 1, 00040 Monteporzio Catone, Rome, Italy.
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Lovreglio P, D'Errico MN, Fustinoni S, Drago I, Barbieri A, Sabatini L, Carrieri M, Apostoli P, Soleo L. Biomarkers of internal dose for the assessment of environmental exposure to benzene. ACTA ACUST UNITED AC 2011; 13:2921-8. [DOI: 10.1039/c1em10512d] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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58
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Fustinoni S, Campo L, Mercadante R, Manini P. Methodological issues in the biological monitoring of urinary benzene and S-phenylmercapturic acid at low exposure levels. J Chromatogr B Analyt Technol Biomed Life Sci 2010; 878:2534-40. [DOI: 10.1016/j.jchromb.2009.11.045] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2009] [Revised: 11/12/2009] [Accepted: 11/27/2009] [Indexed: 11/28/2022]
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Protano C, Guidotti M, Manini P, Petyx M, La Torre G, Vitali M. Benzene exposure in childhood: Role of living environments and assessment of available tools. ENVIRONMENT INTERNATIONAL 2010; 36:779-787. [PMID: 20591482 DOI: 10.1016/j.envint.2010.06.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2010] [Revised: 06/03/2010] [Accepted: 06/06/2010] [Indexed: 05/29/2023]
Abstract
Benzene is a widespread air pollutant and a well-known human carcinogen. Evidence is needed regarding benzene intake in the pediatric age group. We investigated the use of urinary (u) trans,trans-muconic acid (t,t-MA), S-phenylmercapturic acid (SPMA), and unmodified benzene (UB) for assessing exposure to low concentrations of environmental benzene and the role of living environment on benzene exposure in childhood. u-t,t-MA, u-SPMA, u-UB and u-cotinine were measured in urine samples of 243 Italian children (5-11 years) recruited in a cross-sectional study. Analytical results were compared with data obtained from questionnaires about participants' main potential exposure factors. u-UB, u-t,t-MA and u-SPMA concentrations were about 1.5-fold higher in children living in urban areas than in those in the rural group. Univariate analyses showed that u-UB was the only biomarker able to discriminate secondhand smoke (SHS) exposure in urban and rural children (medians=411.50 and 210.50 ng/L, respectively); these results were confirmed by the strong correlation between u-UB and u-cotinine in the SHS-exposed group and by multivariate analyses. A regression model on u-SPMA showed that the metabolite is related to residence area (p<0.001), SHS exposure (p=0.048) and gender (p=0.027). u-UB is the best marker of benzene exposure in children in the present study, and it can be used as a good carcinogen-derived biomarker of exposure to passive smoking, especially related to benzene, when urine sample is collected at the end of the day. In addition, it is important to highlight that SHS resulted the most important contributor to benzene exposure, underlining the need for an information campaign against passive smoking exposure.
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Affiliation(s)
- Carmela Protano
- Department of Public Health Sciences G. Sanarelli, P. le Aldo Moro 5, 00185, Sapienza University, Rome, Italy.
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Kawai T, Sumino K, Ohashi F, Ikeda M. Use of a holder-vacuum tube device to save on-site hands in preparing urine samples for head-space gas-chromatography, and its application to determine the time allowance for sample sealing. INDUSTRIAL HEALTH 2010; 49:24-29. [PMID: 20823637 DOI: 10.2486/indhealth.ms1157] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
To facilitate urine sample preparation prior to head-space gas-chromatographic (HS-GC) analysis. Urine samples containing one of the five solvents (acetone, methanol, methyl ethyl ketone, methyl isobutyl ketone and toluene) at the levels of biological exposure limits were aspirated into a vacuum tube via holder, a device commercially available for venous blood collection (the vacuum tube method). The urine sample, 5 ml, was quantitatively transferred to a 20-ml head-space vial prior to HS-GC analysis. The loaded tubes were stored at +4 ℃ in dark for up to 3 d. The vacuum tube method facilitated on-site procedures of urine sample preparation for HS-GC with no significant loss of solvents in the sample and no need of skilled hands, whereas on-site sample preparation time was significantly reduced. Furthermore, no loss of solvents was detected during the 3-d storage, irrespective of hydrophilic (acetone) or lipophilic solvent (toluene). In a pilot application, high performance of the vacuum tube method in sealing a sample in an air-tight space succeeded to confirm that no solvent will be lost when sealing is completed within 5 min after urine voiding, and that the allowance time is as long as 30 min in case of toluene in urine. The use of the holder-vacuum tube device not only saves hands for transfer of the sample to air-tight space, but facilitates sample storage prior to HS-GC analysis.
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Affiliation(s)
- Toshio Kawai
- Osaka Occupational Health Service Center, Japan Industrial Health Safety and Health Association, Osaka 550-0001, Japan.
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Rappaport SM, Kim S, Lan Q, Li G, Vermeulen R, Waidyanatha S, Zhang L, Yin S, Smith MT, Rothman N. Human benzene metabolism following occupational and environmental exposures. Chem Biol Interact 2010; 184:189-95. [PMID: 20026321 PMCID: PMC3072712 DOI: 10.1016/j.cbi.2009.12.017] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2009] [Revised: 12/04/2009] [Accepted: 12/14/2009] [Indexed: 11/16/2022]
Abstract
We previously reported evidence that humans metabolize benzene via two enzymes, including a hitherto unrecognized high-affinity enzyme that was responsible for an estimated 73% of total urinary metabolites [sum of phenol (PH), hydroquinone (HQ), catechol (CA), E,E-muconic acid (MA), and S-phenylmercapturic acid (SPMA)] in nonsmoking females exposed to benzene at sub-saturating (ppb) air concentrations. Here, we used the same Michaelis-Menten-like kinetic models to individually analyze urinary levels of PH, HQ, CA and MA from 263 nonsmoking Chinese women (179 benzene-exposed workers and 84 control workers) with estimated benzene air concentrations ranging from less than 0.001-299 ppm. One model depicted benzene metabolism as a single enzymatic process (1-enzyme model) and the other as two enzymatic processes which competed for access to benzene (2-enzyme model). We evaluated model fits based upon the difference in values of Akaike's Information Criterion (DeltaAIC), and we gauged the weights of evidence favoring the two models based upon the associated Akaike weights and Evidence Ratios. For each metabolite, the 2-enzyme model provided a better fit than the 1-enzyme model with DeltaAIC values decreasing in the order 9.511 for MA, 7.379 for PH, 1.417 for CA, and 0.193 for HQ. The corresponding weights of evidence favoring the 2-enzyme model (Evidence Ratios) were: 116.2:1 for MA, 40.0:1 for PH, 2.0:1 for CA and 1.1:1 for HQ. These results indicate that our earlier findings from models of total metabolites were driven largely by MA, representing the ring-opening pathway, and by PH, representing the ring-hydroxylation pathway. The predicted percentage of benzene metabolized by the putative high-affinity enzyme at an air concentration of 0.001 ppm was 88% based upon urinary MA and was 80% based upon urinary PH. As benzene concentrations increased, the respective percentages of benzene metabolized to MA and PH by the high-affinity enzyme decreased successively to 66 and 77% at 0.1 ppm, 20 and 58% at 1 ppm, and 2.7 and 17% at 10 ppm. This indicates that the putative high-affinity enzyme was active primarily below 1 ppm and favored the ring-opening pathway.
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Affiliation(s)
- Stephen M Rappaport
- School of Public Health, University of California, Berkeley, CA 94720-7356, USA.
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Analysis of hydroquinone and catechol in peripheral blood of benzene-exposed workers. Chem Biol Interact 2010; 184:182-8. [DOI: 10.1016/j.cbi.2009.12.010] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2009] [Revised: 12/10/2009] [Accepted: 12/10/2009] [Indexed: 11/22/2022]
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Manini P, De Palma G, Andreoli R, Mozzoni P, Poli D, Goldoni M, Petyx M, Apostoli P, Mutti A. Occupational exposure to low levels of benzene: Biomarkers of exposure and nucleic acid oxidation and their modulation by polymorphic xenobiotic metabolizing enzymes. Toxicol Lett 2010; 193:229-35. [PMID: 20100551 DOI: 10.1016/j.toxlet.2010.01.013] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2009] [Revised: 01/17/2010] [Accepted: 01/19/2010] [Indexed: 10/19/2022]
Abstract
This study investigated nucleic acid oxidation associated with exposure to benzene at low levels in 239 workers recruited among traffic policemen, taxi drivers and gasoline pump attendants of the city of Parma (Italy). Biomarkers of exposure, namely urinary t,t-muconic acid (t,t-MA) and S-phenylmercapturic acid (S-PMA), urinary cotinine, and urinary biomarkers of nucleic acid oxidation, namely 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo), 8-oxo-7,8-dihydroguanosine (8-oxoGuo) and 8-oxo-7,8-dihydroguanine (8-oxoGua) were determined by liquid chromatography-tandem mass spectrometry. Relevant polymorphisms of NAD(P)H:quinone oxidoreductase (NQO1), glutathione S-transferases M1-1 (GSTM1), T1-1 (GSTT1), and A1 (GSTA1) were characterized by polymerase chain reaction-based methods in a subgroup of subjects. Biomarkers of nucleic acid oxidation were correlated with each other (r> or =0.32, p<0.0001) and with exposure biomarkers (r> or =0.28, p<0.0001). Multiple linear regression models including age, sex and smoking habits as independent variables demonstrated that benzene exposure is associated with oxidation damage to nucleic acid, particularly to RNA (p<0.0001) and is modulated by the NQO1 polymorphism. The study confirmed a significant modulating effect of GSTM1 (p=0.010), GSTT1 (p=0.023) and GSTA1 (p=0.048) polymorphisms on S-PMA excretion, with a significant interaction between GSTM1 and both GSTT1 and GSTA1 (p=0.006 and p=0.037, respectively).
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Affiliation(s)
- Paola Manini
- Department of Clinical Medicine, Nephrology and Health Sciences, University of Parma, Italy.
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Validity of new biomarkers of internal dose for use in the biological monitoring of occupational and environmental exposure to low concentrations of benzene and toluene. Int Arch Occup Environ Health 2009; 83:341-56. [PMID: 19830448 DOI: 10.1007/s00420-009-0469-7] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2009] [Accepted: 09/24/2009] [Indexed: 10/20/2022]
Abstract
OBJECTIVES This study analyzes the validity of new, more sensitive and specific urinary biomarkers of internal dose, namely, urinary benzene for benzene and urinary toluene and S-benzylmercapturic acid (SBMA) for toluene, to assess their efficacy when compared to traditional biomarkers for biological monitoring of occupational exposure to low concentrations of these two toxic substances. METHODS Assessment was made of 41 workers occupationally exposed to benzene and toluene, 18 fuel tanker drivers and 23 filling-station attendants, as well as 31 subjects with no occupational exposure to these toxic substances (controls). Exposure to airborne benzene and toluene was measured using passive Radiello personal samplers worn throughout the work shift. In urine samples collected from all subjects at the end of the workday, both the traditional and the new internal dose biomarkers of benzene and toluene were assessed, as well as creatinine so as to apply suitable adjustments. RESULTS Occupational exposure to benzene and toluene resulted significantly higher in the fuel tanker drivers than the filling-station attendants, and higher in the latter than in controls. Significantly higher concentrations of t,t-muconic acid (t,t-MA), S-phenylmercapturic acid (SPMA), urinary benzene, SBMA and urinary toluene were found in the drivers than the filling-station attendants or the controls. Instead, urinary phenol and hippuric acid were not different in the three groups. In the entire sample, airborne benzene and toluene values were significantly correlated, as were the respective urinary biomarkers, showing coefficients ranging from 0.36 to 0.98. Subdividing the subjects by smoking habit, higher coefficients were evident in non-smokers than in smokers; at multiple regression analysis t,t-MA, SPMA and urinary benzene and toluene were dependent on the number of cigarettes smoked daily and on airborne benzene and toluene, respectively. Instead, SBMA was dependent only on airborne toluene. CONCLUSIONS Our research confirmed the validity of t,t-MA and SPMA for use in the biological monitoring of exposure to low concentrations of benzene. Urinary benzene showed comparable validity to SPMA; both parameters are affected by smoking cigarettes in the hours before urine collection, so it is best to ask subjects to refrain from smoking for 2 h before urine collection. Urinary toluene was found to be a more specific biomarker than SBMA.
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Self-collected urine sampling to study the kinetics of urinary toluene (and o-cresol) and define the best sampling time for biomonitoring. Int Arch Occup Environ Health 2009; 82:703-13. [DOI: 10.1007/s00420-008-0393-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2008] [Accepted: 12/03/2008] [Indexed: 11/26/2022]
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Campo L, Mercadante R, Rossella F, Fustinoni S. Quantification of 13 priority polycyclic aromatic hydrocarbons in human urine by headspace solid-phase microextraction gas chromatography–isotope dilution mass spectrometry. Anal Chim Acta 2009; 631:196-205. [DOI: 10.1016/j.aca.2008.10.041] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2008] [Revised: 10/15/2008] [Accepted: 10/15/2008] [Indexed: 11/29/2022]
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Barbieri A, Violante FS, Sabatini L, Graziosi F, Mattioli S. Urinary biomarkers and low-level environmental benzene concentration: assessing occupational and general exposure. CHEMOSPHERE 2008; 74:64-69. [PMID: 18922558 DOI: 10.1016/j.chemosphere.2008.09.011] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2008] [Revised: 08/04/2008] [Accepted: 09/04/2008] [Indexed: 05/26/2023]
Abstract
The categories of urban workers undergoing prolonged exposure to gasoline due to vehicle emissions, evaporation and traffic fumes are considered occupationally exposed to benzene, even if at low concentrations. The aim of this study was to evaluate the specificity of unmetabolized benzene excreted in urine (UBz) and S-phenylmercapturic acid (SPMA) as biomarkers of exposure to very low levels of benzene, and to study the impact of putative individual confounders like smoking and alcohol habits, co-exposure to other toxicants and body mass index on the exposure assessment. Environmental and biological monitoring of exposure to benzene were performed in 114 Urban Policemen. The mean value of UBz in non-smokers was significantly lower than in either groups of light to moderate smokers and heavy smokers (0.24, 1.82 and 2.82 microg L(-1), respectively). On the contrary, SPMA values did not discriminate exposure resulting from smoking habits. Moreover, the concentration of UBz in non-smokers appears to be correlated with environmental benzene concentration (BenzA) (R(2)=0.13, beta=0.37, p=0.002). On the other hand, no significant correlation was found between SPMA concentration (corrected for creatinine excretion and log transformed, LogSPMA) and LogBenzA (R(2)=0.003, beta=0.05, p=0.6). Our findings reinforce previous research on the use of unmetabolized urinary benzene as a specific and sensitive biomarker of low-level exposure to benzene and confirm that smoking habits strongly influence the excretion of UBz.
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Affiliation(s)
- Anna Barbieri
- Unit of Occupational Medicine, Sant'Orsola Malpighi Hospital, University of Bologna, Bologna, Italy.
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68
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Evaluation of urinary biomarkers of exposure to benzene: correlation with blood benzene and influence of confounding factors. Int Arch Occup Environ Health 2008; 82:985-95. [DOI: 10.1007/s00420-008-0381-6] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2008] [Accepted: 10/21/2008] [Indexed: 11/26/2022]
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69
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Chao YCE, Zhao Y, Kupper LL, Nylander-French LA. Quantifying the relative importance of predictors in multiple linear regression analyses for public health studies. JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL HYGIENE 2008; 5:519-529. [PMID: 18569519 DOI: 10.1080/15459620802225481] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Multiple linear regression analysis is widely used in many scientific fields, including public health, to evaluate how an outcome or response variable is related to a set of predictors. As a result, researchers often need to assess "relative importance" of a predictor by comparing the contributions made by other individual predictors in a particular regression model. Hence, development of valid statistical methods to estimate the relative importance of a set of predictors is of great interest. In this research, the authors considered the relative importance of a predictor when defined by that portion of the squared multiple correlation explained by the contribution of each predictor in the final model of interest. Here, a number of suggested relative importance indices motivated by this definition are reviewed, including the squared zero-order correlation, squared semipartial correlation, Product Measure (i.e., Pratt's Index), General Dominance Index, and Johnson's Relative Weight. The authors compared these indices using data sets from an occupational health study in which human inhalation exposure to styrene was measured and from a laboratory animal study on risk factors for atherosclerosis, and statistical properties using bootstrap methods were examined. The analysis suggests that the General Dominance Index and Johnson's Relative Weight are preferred methods for quantifying the relative importance of predictors in a multiple linear regression model. Johnson's Relative Weight involves significantly less computational burden than the General Dominance Index when the number of predictors in the final model is large.
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Affiliation(s)
- Yi-Chun E Chao
- Department of Environmental Sciences and Engineering, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7431, USA
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70
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Lin YS, Egeghy PP, Rappaport SM. Relationships between levels of volatile organic compounds in air and blood from the general population. JOURNAL OF EXPOSURE SCIENCE & ENVIRONMENTAL EPIDEMIOLOGY 2008; 18:421-9. [PMID: 18059425 DOI: 10.1038/sj.jes.7500635] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
The relationships between levels of volatile organic compounds (VOCs) in blood and air have not been well characterized in the general population where exposure concentrations are generally at parts per billion levels. This study investigates relationships between the levels of nine VOCs, namely, benzene, chloroform, 1,4-dichlorobenzene, ethylbenzene, methyl tert-butyl ether (MTBE), tetrachloroethene, toluene, and m-/p- and o-xylene, in blood and air from a stratified random sample of the general US population. We used data collected from 354 participants, including 89 smokers and 265 nonsmokers, aged 20-59 years, who provided samples of blood and air in the National Health and Nutrition Examination Survey (NHANES) 1999-2000. Demographic and physiological characteristics were obtained from self-reported information; smoking status was determined from levels of serum cotinine. Multiple linear regression models were used to investigate the relationships between VOC levels in air and blood, while adjusting for effects of smoking and demographic factors. Although levels of VOCs in blood were positively correlated with the corresponding air levels, the strength of association (R(2)) varied from 0.02 (ethylbenzene) to 0.68 (1,4-DCB). Also the blood-air relationships of benzene, toluene, ethylbenzene, and the xylenes (BTEX) were influenced by smoking, exposure-smoking interactions, and by gender, age, and BMI, whereas those of the other VOCs were not. Interestingly, the particular exposure-smoking interaction for benzene was different from those for toluene, ethylbenzene, and the xylenes. Whereas smokers retained more benzene in their blood at increasing exposure levels, they retained less toluene, ethylbenzene, and xylenes at increasing exposure levels. Investigators should consider interaction effects of exposure levels and smoking when exploring the blood-air relationships of the BTEX compounds in the general population.
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Affiliation(s)
- Y S Lin
- Department of Environmental and Occupational Health, School of Public Health, University of North Texas Health Science Center, Fort Worth, Texas, USA
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71
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Lee HS, Yang M. Applications of CYP-450 expression for biomonitoring in environmental health. Environ Health Prev Med 2008; 13:84-93. [PMID: 19568886 DOI: 10.1007/s12199-007-0009-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2007] [Accepted: 09/15/2007] [Indexed: 11/25/2022] Open
Abstract
Cytochrome P450s (CYPs) are one of the first steps in the metabolism of xenobiotics, such as polycyclic aromatic hydrocarbons (PAHs), which are bioactivated into carcinogens. As such, changes in CYP expression are potential biomarkers in human biomonitoring applications. For the proper biomonitoring of environmental toxicants, it is important to understand the biological relevance of each biomarker and the associations among the biomarkers for uses as exposure, effects, and susceptibility biomarkers. Here, we have reviewed various aspects of CYPs for biomonitoring environmental health in terms of the CYP substrates, such as PAHs, aromatic amines, benzene/toluene, and tobacco smoking-related nitrosamines. This review also includes association studies between CYP phenotypical alterations and other exposure, susceptibility, and effect biomarkers. The association studies were mainly performed in CYP gene-transfected cells and noninvasive human biospecies, such as urine and peripheral blood. In conclusion, we suggest that phenotypical alterations in CYPs with exposure to environmental toxicants are useful as susceptibility or effect biomarkers, particularly when the phenotype-related genotypes are unknown.
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Affiliation(s)
- Ho-Sun Lee
- Department of Toxicology, College of Pharmacy, Sookmyung Women's University, 53-12 Chungpa-dong 2 Ka, Yongsan-Ku, Seoul, Republic of Korea
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72
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Buthbumrung N, Mahidol C, Navasumrit P, Promvijit J, Hunsonti P, Autrup H, Ruchirawat M. Oxidative DNA damage and influence of genetic polymorphisms among urban and rural schoolchildren exposed to benzene. Chem Biol Interact 2008; 172:185-94. [PMID: 18282563 DOI: 10.1016/j.cbi.2008.01.005] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2007] [Revised: 01/04/2008] [Accepted: 01/05/2008] [Indexed: 11/25/2022]
Abstract
Traffic related urban air pollution is a major environmental health problem in many large cities. Children living in urban areas are exposed to benzene and other toxic pollutants simultaneously on a regular basis. Assessment of benzene exposure and oxidative DNA damage in schoolchildren in Bangkok compared with the rural schoolchildren was studied through the use of biomarkers. Benzene levels in ambient air at the roadside adjacent to Bangkok schools was 3.95-fold greater than that of rural school areas. Personal exposure to benzene in Bangkok schoolchildren was 3.04-fold higher than that in the rural schoolchildren. Blood benzene, urinary benzene and urinary muconic acid (MA) levels were significantly higher in the Bangkok schoolchildren. A significantly higher level of 8-hydroxy-2'-deoxyguanosine (8-OHdG) in leukocytes and in urine was found in Bangkok children than in the rural children. There was a significant correlation between individual benzene exposure level and blood benzene (rs=0.193, P<0.05), urinary benzene (rs=0.298, P<0.05), urinary MA (rs=0.348, P<0.01), and 8-OHdG in leukocyte (rs=0.130, P<0.05). In addition, a significant correlation between urinary MA and 8-OHdG in leukocytes (rs=0.241, P<0.05) was also found. Polymorphisms of various xenobiotic metabolizing genes responsible for susceptibility to benzene toxicity have been studied; however only the GSTM1 genotypes had a significant effect on urinary MA excretion. Our data indicates that children living in the areas of high traffic density are exposed to a higher level of benzene than those living in rural areas. Exposure to higher level of benzene in urban children may contribute to oxidative DNA damage, suggesting an increased health risk from traffic benzene emission.
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Affiliation(s)
- Nantaporn Buthbumrung
- Laboratory of Environmental Toxicology, Chulabhorn Research Institute, Vipavadee Rangsit Highway, Lak Si, Donmuang, Bangkok 10210, Thailand
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73
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Kim S, Lan Q, Waidyanatha S, Chanock S, Johnson BA, Vermeulen R, Smith MT, Zhang L, Li G, Shen M, Yin S, Rothman N, Rappaport SM. Genetic polymorphisms and benzene metabolism in humans exposed to a wide range of air concentrations. Pharmacogenet Genomics 2007; 17:789-801. [PMID: 17885617 DOI: 10.1097/fpc.0b013e3280128f77] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Using generalized linear models with natural-spline smoothing functions, we detected effects of specific xenobiotic metabolizing genes and gene-environment interactions on levels of benzene metabolites in 250 benzene-exposed and 136 control workers in Tianjin, China (for all individuals, the median exposure was 0.512 p.p.m. and the 10th and 90th percentiles were 0.002 and 6.40 p.p.m., respectively). We investigated five urinary metabolites (E,E-muconic acid, S-phenylmercapturic acid, phenol, catechol, and hydroquinone) and nine polymorphisms in seven genes coding for key enzymes in benzene metabolism in humans {cytochrome P450 2E1 [CYP2E1, rs2031920], NAD(P)H: quinone oxidoreductase [NQO1, rs1800566 and rs4986998], microsomal epoxide hydrolase [EPHX1, rs1051740 and rs2234922], glutathione-S-transferases [GSTT1, GSTM1 and GSTP1(rs947894)] and myeloperoxidase [MPO, rs2333227]}. After adjusting for covariates, including sex, age, and smoking status, NQO1*2 (rs1800566) affected all five metabolites, CYP2E1 (rs2031920) affected most metabolites but not catechol, EPHX1 (rs1051740 or rs2234922) affected catechol and S-phenylmercapturic acid, and GSTT1 and GSTM1 affected S-phenylmercapturic acid. Significant interactions were also detected between benzene exposure and all four genes and between smoking status and NQO1*2 and EPHX1 (rs1051740). No significant effects were detected for GSTP1 or MPO. Results generally support prior associations between benzene hematotoxicity and specific gene mutations, confirm earlier evidence that GSTT1 affects production of S-phenylmercapturic acid, and provide additional evidence that genetic polymorphisms in NQO1*2, CYP2E1, and EPHX1 (rs1051740 or rs2234922) affect metabolism of benzene in the human liver.
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Affiliation(s)
- Sungkyoon Kim
- School of Public Health, University of North Carolina, Chapel Hill, NC 27599, USA
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74
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Yi B, Yang JY, Yang M. Past and future applications of CYP450-genetic polymorphisms for biomonitoring of environmental toxicants. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART C, ENVIRONMENTAL CARCINOGENESIS & ECOTOXICOLOGY REVIEWS 2007; 25:353-377. [PMID: 18000786 DOI: 10.1080/10590500701704037] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Cytochrome P450s (CYPs) are a huge gene superfamily of heme enzymes involved in xenobioitc as well as endobiotic metabolism. They play a critical role in adaptation to environmental changes for survival of living organisms. In addition, the huge environmental loads of human-made chemicals are biotransformed into bioactive or detoxified forms by CYPs. Thus, CYPs have been used for biomonitoring of environmental pollutants, screening of their metabolisms and exploring remedy. In particular, the induction or inhibition of CYPs has been applied to exposure monitoring of environmental toxicants, which are biotransformed by CYPs. This review considers past and future applications of CYP-genetic polymorphisms as susceptibility biomarkers for biomonitoring. Furthermore, we suggest the needs for further understanding of the characteristics of each CYP isozyme, consideration of real-life exposures such as mixed contamination with various chemicals, and incorporation of the presence of other phase I and phase II enzymes, for proper applications of CYP polymorphisms on biomonitoring.
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Affiliation(s)
- Bitna Yi
- Sookmyung Women's University, College of Pharmacy, Seoul, Korea
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75
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Paustenbach DJ, Gaffney SH, Scott PK, Brown JL, Panko JM. High background levels of urinary benzene metabolites found in a volunteer study. JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL HYGIENE 2007; 4:71-7. [PMID: 17530536 DOI: 10.1080/15459620701426016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
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76
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Johnson ES, Langård S, Lin YS. A critique of benzene exposure in the general population. THE SCIENCE OF THE TOTAL ENVIRONMENT 2007; 374:183-98. [PMID: 17261327 DOI: 10.1016/j.scitotenv.2006.11.045] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2006] [Revised: 11/21/2006] [Accepted: 11/28/2006] [Indexed: 05/13/2023]
Abstract
Benzene risk assessment indicates that exposure to a time-weighted average (TWA) of 1-5 parts per million (ppm) benzene in ambient air for 40 years is associated with an increased risk of acute myeloid leukemia. Decreased white blood cell count, platelet count and other hematological indices have also been observed in persons exposed to as low as 1 ppm airborne benzene. Evidence from studies worldwide consistently shows elevated levels of benzene biomarkers that are equivalent to 0.1-2 ppm benzene in ambient air, or even higher in the general population without occupational exposure to benzene (including children). The public health significance of these observations depends on to what extent these levels reflect actual benzene exposure, and whether such exposures are life-long or at least occur frequently enough to pose a possible health threat. We reviewed the evidence and discussed possible explanations for these observations. It was concluded that while there is reason to suspect that benzene contributes significantly to elevated levels of biomarkers in the general population, there is growing concern that this cannot be definitively ascertained without concomitant consideration of the role of other factors such as metabolic polymorphisms and sources of biomarkers other than benzene, which have been insufficiently studied to date. Such studies are urgently needed for valid assessment of this potential public health problem.
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Affiliation(s)
- Eric S Johnson
- Department of Environmental and Occupational Health, School of Public Health, University of North Texas Health Science Center, 3500 Camp Bowie Blvd, Fort Worth, TX 76107, United States.
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77
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Bollati V, Baccarelli A, Hou L, Bonzini M, Fustinoni S, Cavallo D, Byun HM, Jiang J, Marinelli B, Pesatori AC, Bertazzi PA, Yang AS. Changes in DNA methylation patterns in subjects exposed to low-dose benzene. Cancer Res 2007; 67:876-80. [PMID: 17283117 DOI: 10.1158/0008-5472.can-06-2995] [Citation(s) in RCA: 493] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Aberrant DNA methylation patterns, including global hypomethylation, gene-specific hypermethylation/hypomethylation, and loss of imprinting (LOI), are common in acute myelogenous leukemia (AML) and other cancer tissues. We investigated for the first time whether such epigenetic changes are induced in healthy subjects by low-level exposure to benzene, a widespread pollutant associated with AML risk. Blood DNA samples and exposure data were obtained from subjects with different levels of benzene exposure, including 78 gas station attendants, 77 traffic police officers, and 58 unexposed referents in Milan, Italy (personal airborne benzene range, < 6-478 microg/m(3)). Bisulfite-PCR pyrosequencing was used to quantitate DNA methylation in long interspersed nuclear element-1 (LINE-1) and AluI repetitive elements as a surrogate of genome-wide methylation and examine gene-specific methylation of MAGE-1 and p15. Allele-specific pyrosequencing of the H19 gene was used to detect LOI in 96 subjects heterozygous for the H19 imprinting center G/A single-nucleotide polymorphism. Airborne benzene was associated with a significant reduction in LINE-1 (-2.33% for a 10-fold increase in airborne benzene levels; P = 0.009) and AluI (-1.00%; P = 0.027) methylation. Hypermethylation in p15 (+0.35%; P = 0.018) and hypomethylation in MAGE-1 (-0.49%; P = 0.049) were associated with increasing airborne benzene levels. LOI was found only in exposed subjects (4 of 73, 5.5%) and not in referents (0 of 23, 0.0%). However, LOI was not significantly associated with airborne benzene (P > 0.20). This is the first human study to link altered DNA methylation, reproducing the aberrant epigenetic patterns found in malignant cells, to low-level carcinogen exposure.
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Affiliation(s)
- Valentina Bollati
- Molecular Epidemiology Laboratory, Department of Environmental and Occupational Health, University of Milan, Via San Barnaba 8, 20122 Milan, Italy.
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78
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Manini P, De Palma G, Andreoli R, Poli D, Mozzoni P, Folesani G, Mutti A, Apostoli P. Environmental and biological monitoring of benzene exposure in a cohort of Italian taxi drivers. Toxicol Lett 2006; 167:142-51. [PMID: 17056211 DOI: 10.1016/j.toxlet.2006.08.016] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2006] [Revised: 08/29/2006] [Accepted: 08/31/2006] [Indexed: 11/20/2022]
Abstract
An integrated approach based on ambient and biological monitoring, the latter including both biomarkers of exposure and susceptibility, was applied to characterize benzene exposure in a group of 37 taxi drivers of the city of Parma (Italy). Airborne benzene concentrations were assessed by 24 h personal sampling and work-shift sampling inside the taxicab using passive samplers (Radiello). Benzene metabolites, trans,trans-muconic acid (t,t-MA) and S-phenylmercapturic acid (S-PMA), and urinary cotinine as biomarker of smoking habits were measured by isotopic dilution liquid chromatography tandem mass spectrometry in both pre-shift (PS) and end-of-shift (EOS) samples. Urinary benzene (U-B) levels were determined by solid-phase microextraction gas chromatography-mass spectrometry in EOS samples. Relevant polymorphisms of microsomal epoxide hydrolase, NAD(P)H:quinone oxidoreductase, glutathione S-transferases M1-1 (GSTM1), T1-1, and A1 were characterized by PCR-based methods. Mean airborne benzene concentration was 5.85 +/- 1.65 microg/m3, as assessed by 24 h personal sampling integrating for work-shift, indoor or general environment activities. Significantly, higher benzene concentrations were detected in the taxicab during the work-shift (7.71 +/- 1.95 microg/m3, p < 0.005). Smokers eliminated significantly higher concentrations of U-B and S-PMA than non-smokers in EOS samples [geometric mean (geometric S.D.): 2.58 (4.23) versus 0.44 (1.79) microg/l for U-B; 3.79 (1.50) versus 2.14 (1.87) microg/gcreat. for S-PMA, p < 0.002]. Within smokers, S-PMA concentrations significantly increased at the end of the work-shift compared to pre-shift values (p < 0.05). t,t-MA showed a similar behaviour, although differences were not significant. In the narrow range examined, no correlation was observed between air benzene concentration and urinary biomarkers. All benzene biomarkers but EOS t,t-MA were correlated with U-cotinine (p < 0.05). GSTM1 polymorphism significantly modulated S-PMA excretion, as subjects bearing the GSTM1pos genotype [3.61 (1.15) microg/gcreat.] excreted significantly higher S-PMA concentrations than GSTM1null subjects [2.19 (1.18) microg/gcreat., p < 0.05].
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Affiliation(s)
- Paola Manini
- Laboratory of Industrial Toxicology, Department of Clinical Medicine, Nephrology and Health Sciences, University of Parma, Via Gramsci 14, 43100 Parma, Italy.
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79
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Kim S, Vermeulen R, Waidyanatha S, Johnson BA, Lan Q, Rothman N, Smith MT, Zhang L, Li G, Shen M, Yin S, Rappaport SM. Using urinary biomarkers to elucidate dose-related patterns of human benzene metabolism. Carcinogenesis 2005; 27:772-81. [PMID: 16339183 DOI: 10.1093/carcin/bgi297] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Although the toxicity of benzene has been linked to its metabolism, the dose-related production of metabolites is not well understood in humans, particularly at low levels of exposure. We investigated unmetabolized benzene in urine (UBz) and all major urinary metabolites [phenol (PH), E,E-muconic acid (MA), hydroquinone (HQ) and catechol (CA)] as well as the minor metabolite, S-phenylmercapturic acid (SPMA), in 250 benzene-exposed workers and 139 control workers in Tianjin, China. Median levels of benzene exposure were approximately 1.2 p.p.m. for exposed workers (interquartile range: 0.53-3.34 p.p.m.) and 0.004 p.p.m. for control workers (interquartile range: 0.002-0.007 p.p.m.). (Exposures of control workers to benzene were predicted from levels of benzene in their urine.) Metabolite production was investigated among groups of 30 workers aggregated by their benzene exposures. We found that the urine concentration of each metabolite was consistently elevated when the group's median benzene exposure was at or above the following air concentrations: 0.2 p.p.m. for MA and SPMA, 0.5 p.p.m. for PH and HQ, and 2 p.p.m. for CA. Dose-related production of the four major metabolites and total metabolites (micromol/l/p.p.m. benzene) declined between 2.5 and 26-fold as group median benzene exposures increased between 0.027 and 15.4 p.p.m. Reductions in metabolite production were most pronounced for CA and PH<1 p.p.m., indicating that metabolism favored production of the toxic metabolites, HQ and MA, at low exposures.
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Affiliation(s)
- Sungkyoon Kim
- School of Public Health, University of North Carolina, Chapel Hill, NC 27599, and National Cancer Institute (NCI), National Institutes of Health (NIH), Department of Health and Human Services (DHHS), Bethesda, MD 20892, USA
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