Exposure, respiratory symptoms, lung function and inflammation response of road-paving asphalt workers.

BACKGROUND: Controversy exists as to the health effects of exposure to asphalt and crumb rubber modified (CRM) asphalt, which contains recycled rubber tyres. OBJECTIVE: To assess exposures and effects on airway symptoms, lung function and inflammation biomarkers in conventional and CRM asphalt road pavers. METHODS: 116 conventional asphalt workers, 51 CRM asphalt workers and 100 controls were investigated. A repeated-measures analysis included 31 workers paving with both types of asphalt. Exposure to dust, nitrosamines, benzothiazole and polycyclic aromatic hydrocarbon (PAH) was measured in worksites. Self-reported symptoms, spirometry test and blood sampling were conducted prework and postwork. Symptoms were further collected during off-season for asphalt paving. RESULTS: Dust, PAHs and nitrosamine exposure was highly varied, without difference between conventional and CRM asphalt workers. Benzothiazole was higher in CRM asphalt workers (p<0.001). Higher proportions of asphalt workers than controls reported eye symptoms with onset in the current job. Decreased lung function from preworking to postworking was found in CRM asphalt workers and controls. Preworking interleukin-8 was higher in CRM asphalt workers than in the controls, followed by a decrement after 4 days of working. No differences in any studied effects were found between conventional and CRM asphalt paving. CONCLUSION: CRM asphalt workers are exposed to higher benzothiazole. Further studies are needed to identify the source of nitrosamines in conventional asphalt. Mild decrease in lung function in CRM asphalt workers and work-related eye symptoms in both asphalt workers were observed. However, our study did not find strong evidence for severe respiratory symptoms and inflammation response among asphalt workers.

A simple and highly sensitive UPLC-ESI-MS/MS method for the simultaneous quantification of nicotine, cotinine, and the tobacco-specific carcinogens N'-nitrosonornicotine and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone in serum samples.

According to the World Health Organization, the consumption of tobacco products is the single largest cause of preventable deaths in the world, exceeding the total aggregated number of deaths caused by diseases such as AIDS, tuberculosis, and malaria. An important element in the evaluation of the health risks associated with the consumption of tobacco products is the assessment of the internal exposure to the tobacco constituents responsible for their addictive (e.g. nicotine) and carcinogenic (e.g. N-nitrosamines such as NNN and NNK) properties. However, the assessment of the serum levels of these compounds is often challenging from an analytical standpoint, in particular when limited sample volumes are available and low detection limits are required. Currently available analytical methods often rely on complex multi-step sample preparation procedures, which are prone to low analyte recoveries and ex-vivo contamination due to the ubiquitous nature of these compounds as background contaminants. In order to circumvent these problems, we report a facile and highly sensitive method for the simultaneous quantification of nicotine, cotinine, NNN, and NNK in serum samples. The method relies on a simple "one pot" liquid-liquid extraction procedure and isotope dilution ultra-high pressure (UPLC) hydrophilic interaction liquid chromatography (HILIC) coupled with tandem mass spectrometry. The method requires only 10µL of serum and presents a limit of quantification of 0.02nmol (3000pg/mL) nicotine, 0.6pmol (100pg/mL) cotinine, 0.05pmol NNK (10pg/mL), and 0.06pmol NNN (10pg/mL), making it appropriate for pharmacokinetic evaluations.

UPLC-MS/MS method for the determination of tobacco-specific biomarker NNAL, tamoxifen and its main metabolites in rat plasma.

Cigarette smoke is known to interact with tamoxifen-metabolizing enzymes and transporters and potentially affect its treatment outcome. 4-(N-nitrosomethylamino)-1-(3-pyridyl)-1-butanol (NNAL) is an important metabolite of 4-(methylnitro-samino)-1-(3-pyridyl)-1-butanone (NNK) because it is frequently used as a biomarker to assess human smoke exposure. In order to study the potential pharmacokinetic interaction between cigarette smoke and tamoxifen in rats a UPLC-MS/MS method for the simultaneous determination of NNAL and tamoxifen along with its metabolites in rat plasma has been developed and validated. Analytes were extracted with methanol and separated on a HSS T3 column by a gradient elution with the mobile phase consisting of acetonitrile and water. The lower limits of quantitation ranged from 0.05 to 0.62 ng/mL. Precisions showed RSD <15.8% and accuracy in the range 80.6-116.0%. Mean analyte recoveries ranged from 76.9 to 108.4%. The method was successfully applied to study the effects of cigarette smoke condensate (CSC), NNK and benzo(a)pyrene pre-treatment on the pharmacokinetics of tamoxifen and its metabolites in rats. Significant effects of CSC, NNK, benzo(a)pyrene were observed on pharmacokinetics of tamoxifen and its metabolites. We also found that plasma NNAL levels are statistically significant correlated with plasma 4-hydroxy-tamoxifen and endoxifen.

Interactions Between Diet and Exposure to Secondhand Smoke on Metabolic Syndrome Among Children: NHANES 2007-2010.

CONTEXT: Metabolic syndrome is likely influenced by a complex interaction between exposure to secondhand smoke (SHS) and diet, but no studies have evaluated this relationship. OBJECTIVE: This study aimed to investigate the interaction between diet and exposure to SHS on metabolic syndrome among 12-19 year olds. DESIGN AND PARTICIPANTS: We used weighted logistic regression, adjusting for potential confounders, to examine interaction of these risk factors on the prevalence of metabolic syndrome among 12-19 year olds participating in the National Health and Nutrition Examination Survey (2007-2010). Interaction was assessed by introducing product terms between SHS (4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol, cotinine, and self-report) and the individual nutrients (dietary fiber, eicosapentaenoic acid, docosahexaenoic acid, vitamin C, and vitamin E) and nutrient patterns in separate models; the relative excess risk due to interaction was used to evaluate interaction on the additive scale. RESULTS: The joint effect between high exposure to SHS and low levels of certain nutrients (vitamin E and omega-3 polyunsaturated fatty acids) on metabolic syndrome risk was greater than would be expected from the effects of the individual exposures alone (for example, relative excess risk due to interaction for SHS and vitamin E = 7.5; 95% confidence interval, 2.5-17.8). CONCLUSIONS: Prevention strategies for metabolic syndrome aimed at reducing SHS exposures and improving diet quality may exceed the expected benefits based on targeting these risk factors separately.

A cross-sectional study of biomarkers of exposure and effect in smokers and moist snuff consumers.

BACKGROUND: Cigarette smoking is a major risk factor for several chronic diseases. Epidemiological data indicate the use of smokeless tobacco (ST) is associated with significantly lower risk for smoking-related diseases compared to cigarettes. Several biomarkers of exposure (BioExp) and effect (BioEff) associated with smoking and use of moist snuff (ST) were evaluated. METHODS: A single site, cross-sectional clinical study enrolled three groups of generally healthy male smokers (SMK), moist snuff consumers (MSC), and non-tobacco consumers (NTC), and several BioExp and BioEff were evaluated. RESULTS: Blood and urinary BioExp, including total nicotine equivalents and tobacco-specific nitrosamines, were higher in MSC compared to SMK. Biomarkers of combustion-related toxicants and cadmium were elevated in SMK. Elevated levels of some BioEff associated with oxidative stress (urinary isoprostanes and leukotriene E4), inflammation (white blood cell count), platelet activation (thromboxane metabolites), and lipid metabolism (apolipoprotein B100 and oxidized low-density lipoprotein) were observed in SMK relative to NTC and MSC (all p<0.05). The non-smoking groups (MSC and NTC) showed similar levels of combustion-related BioExp and BioEff. CONCLUSIONS: Higher levels of exposure to nicotine and some N'-nitrosamines may be observed in MSC, and SMK are exposed to higher levels of combustion-related toxicants. Changes in BioEff consistent with some aspects of inflammation, oxidative stress, and altered lipid metabolism were detected in SMK compared to the non-smoking groups. The biomarker data further improve our understanding of pathophysiological changes and the risk continuum associated with various tobacco products, and could be useful components of future assessments of tobacco products.

Associations Between Genetic Ancestries and Nicotine Metabolism Biomarkers in the Multiethnic Cohort Study.

Differences in internal dose of nicotine and tobacco-derived carcinogens among ethnic/racial groups have been observed. In this study, we explicitly examined the relationships between genetic ancestries (genome-wide average) and 19 tobacco-derived biomarkers in smokers from 3 admixed groups in the Multiethnic Cohort Study (1993-present), namely, African ancestry in African Americans (n = 362), Amerindian ancestry in Latinos (n = 437), and Asian and Native Hawaiian ancestries in Native Hawaiians (n = 300). After multiple comparison adjustment, both African and Asian ancestries were significantly related to a greater level of free cotinine; African ancestry was also significantly related to lower cotinine glucuronidation (P's < 0.00156). The predicted decrease in cotinine glucuronidation was 8.6% (P = 4.5 × 10(-6)) per a 20% increase in African ancestry. Follow-up admixture mapping revealed that African ancestry in a 12-Mb region on chromosome 4q was related to lower cotinine glucuronidation (P's < 2.7 × 10(-7), smallest P = 1.5 × 10(-9)), although this is the same region reported in our previous genome-wide association study. Our results implicate a genetic ancestral component in the observed ethnic/racial variation in nicotine metabolism. Further studies are needed to identify the underlying genetic variation that could potentially be ethnic/racial specific.

Role of CYP2A13 in the bioactivation and lung tumorigenicity of the tobacco-specific lung procarcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone: in vivo studies using a CYP2A13-humanized mouse model.

The tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), which is abundant in tobacco smoke, is a potent lung procarcinogen. The present study was aimed to prove that transgenic expression of human cytochrome P450 2A13 (CYP2A13), known to be selectively expressed in the respiratory tract and be the most efficient enzyme for NNK bioactivation in vitro, will enhance NNK bioactivation and NNK-induced tumorigenesis in the mouse lung. Kinetic parameters of NNK bioactivation in vitro and incidence of NNK-induced lung tumors in vivo were determined for wild-type, Cyp2a5-null and CYP2A13-humanized (CYP2A13-transgenic/Cyp2a5-null) mice. As expected, in both liver and lung microsomes, the loss of CYP2A5 resulted in significant increases in Michaelis constant (K m) values for the formation of 4-oxo-4-(3-pyridyl)-butanal, representing the reactive intermediate that can lead to the formation of O(6)-methylguanine (O(6)-mG) DNA adducts; however, the gain of CYP2A13 at a fraction of the level of mouse lung CYP2A5 led to recovery of the activity in the lung, but not in the liver. The levels of O(6)-mG, the DNA adduct highly correlated with lung tumorigenesis, were significantly higher in the lungs of CYP2A13-humanized mice than in Cyp2a5-null mice. Moreover, incidences of lung tumorigenesis were significantly greater in CYP2A13-humanized mice than in Cyp2a5-null mice, and the magnitude of the differences in incidence was greater at low (30mg/kg) than at high (200mg/kg) NNK doses. These results indicate that CYP2A13 is a low K m enzyme in catalyzing NNK bioactivation in vivo and support the notion that genetic polymorphisms of CYP2A13 can influence the risks of tobacco-induced lung tumorigenesis in humans.

SPE-HPLC-MS/MS method for the trace analysis of tobacco-specific N-nitrosamines and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol in rabbit plasma using tetraazacalix[2]arene[2]triazine-modified silica as a sorbent.

Tobacco-specific N-nitrosamines (TSNAs), including N'-nitrosonornicotine, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone, N'-nitrosoanatabine, and N'-nitrosoanabasine, have been implicated as a source of carcinogenicity in tobacco and cigarette smoke. We present a rapid and effective method comprising SPE based on tetraazacalix[2]arene[2]triazine-modified silica as sorbent and analysis with HPLC-MS/MS for the determination of TSNAs and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), a metabolite of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone, in rabbit plasma. The linear dynamic ranges were 10-2000 pg/mL for NNAL and 4-2000 pg/mL for the four TSNAs with good correlation coefficients (>0.9965). The LODs were in the range of 0.9-3.7 pg/mL, and the LOQs were between 2.9 and 12.3 pg/mL. The accuracies of the method were also evaluated and found to be in the range of 90.1-113.3%. This method is promising to be applied to the preconcentration and determination of TSNAs and NNAL in smoke and human body fluids.

Simultaneous determination of NNK and its seven metabolites in rabbit blood by hydrophilic interaction liquid chromatography-tandem mass spectrometry.

A hydrophilic interaction liquid chromatographic-tandem mass spectrometric (HILIC-MS-MS) method for investigation of the in vivo metabolism of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), a potent carcinogen, in rabbit blood has been developed and validated. This method achieved excellent repeatability and accuracy. Recovery ranged from 76.9 to 116.3 % and precision (as RSD) between 0.53 and 6.52 %. Linearity was good for all compounds (R(2)>0.9990) and the limit of detection (LOD) ranged from 0.016 to 0.082 ng mL(-1). Pharmacokinetic analysis indicated that NNK was rapidly eliminated in vivo in rabbit blood and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) was the major metabolite. The hydroxy acid, keto acid, and NNAL-N-oxide were also important metabolites in rabbit blood. It is probable that α-methylene hydroxylation was the major pathway of α-hydroxylation of NNK and NNAL in the rabbit.

Analysis of N'-nitrosonornicotine and its metabolites in rabbit blood with liquid chromatography/tandem mass spectrometric method.

N'-nitrosonornicotine (NNN) is a strong carcinogen. The metabolic study of NNN in vivo will help us to further understand it, however, trace detection in complex matrices requires highly sensitive detection methods. After the chromatographic conditions and mass spectrometric conditions had been optimized and confirmed, a method for determining NNN and its metabolites in rabbit blood by high-performance liquid chromatography/tandem mass spectrometry (HPLC-MS/MS) was established. The results showed that precisions (R.S.Ds) were between 0.5% and 8.62%, the recoveries ranged from 80% to 111%. Linearity was observed for all compounds with detection limits ranging from 0.039 ng mL⁻¹ to 0.217 ng mL⁻¹. Metabolic curves and pharmacokinetic parameters were obtained for NNN and its metabolites. The elimination half-life of NNN was 30 min and the main metabolite of NNN was 4-hydroxy-4-(3-pyridyl)-butyric acid (hydroxy acid) and the major metabolic pathway was 5'-hydroxylation and subsequent secondary metabolite formation.

4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone is correlated with 8-hydroxy-2'-deoxyguanosine in humans after exposure to environmental tobacco smoke.

Cigarette smoking and exposure to environmental tobacco smoke (ETS) are important risk factors for many cancers. However, exposure doses have usually not been quantitatively assessed in human studies. In humans 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol and its glucuronate conjugate (defined as total NNAL) are the major metabolites of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone, a cigarette-specific carcinogen. Although animal studies have shown that exposure to cigarette smoke increases tissue oxidative DNA damage, the relationship between cigarette smoke and 8-hydroxydeoxyguanosine (8-OHdG) is not consistent in human studies. In the present study, we have developed a simple, sensitive, and robust LC-MS/MS method for quantifying total NNAL and 8-OHdG concentrations in human plasma. We quantified total NNAL and 8-OHdG in plasma as well as 8-OHdG in urine of 121 healthy male subjects. Total NNAL levels were significantly higher in ever-smokers than in never-smokers. Furthermore, total NNAL levels in plasma were increased with numbers of cigarettes smoked per day in ever-smokers. It suggests that total NNAL in plasma is a good biomarker for cigarette smoke exposure. After stratifying by smoking status and adjusting for age, ETS exposure and occupation category, total NNAL was associated with plasma and urinary 8-OHdG in never-smokers, but not in ever-smokers. Since total NNAL levels in nonsmokers represented the ETS exposure, it appears that 8-OHdG levels are dose-dependently correlated with their ETS exposure dose. Furthermore, this correlation supports the hypothesis that oxidative DNA damage is one of major adverse effects induced by ETS exposure in humans.

Temporal stability of urinary and plasma biomarkers of tobacco smoke exposure among cigarette smokers.

Intraindividual variability of measurements of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), nicotine, cotinine, and r-1,t-2,3,c-4-tetrahydroxy-1,2,3,4-tetrahydrophenanthrene (PheT) over time is uncertain. From 70 habitual smokers' plasma and urine sampled bimonthly for a year we analysed plasma for NNAL, cotinine and PheT, and urine for NNAL, cotinine and nicotine. We estimated the intraclass correlation coefficients (rho(I)) for each measurement. Plasma and creatinine-corrected urinary NNAL were stable (rho(I) > or =70%); plasma PheT and plasma and urinary total cotinine were fairly stable (rho(I) > or =50%), but urinary nicotine rho(I) approximately 40% was not. Except for nicotine, single measurements from plasma or urine adequately represent individual mean exposure over time.

Evaluation of biomarkers of exposure and potential harm in smokers, former smokers and never-smokers.

BACKGROUND: The objective of this study was to obtain baseline data on biomarkers of exposure (BoE) and biomarkers of potential harm (BoPH) in smokers, former smokers and never-smokers. METHODS: This was a cross-sectional study of 80 healthy male and female volunteers over 21 years old, self-selected for smoking status. Subjects were prescreened by medical staff at an independent clinical research unit, within 1 week prior to a single overnight residential visit and sample collection. RESULTS: All BoE were able to differentiate between the two smoking groups and smokers from all nonsmokers. There was a strong correlation between cigarettes smoked per day and total urinary nicotine equivalents (TNE; r=0.85). TNE correlated better with 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol levels than cigarettes smoked per day (r=0.75 and r=0.56, respectively). Of the BoPH included in this study, seven (11-dehydro-thromboxane B2, 2, 3-dinorthrom-boxane B2, 8-epi prostaglandin F(2alpha), 8-hydroxy-2 deoxyguanosine, cis-thymidine glycol, low-density lipoprotein cholesterol and IgG) were significantly different between the group who smoked more cigarettes per day and never-smokers. These differences became more apparent and extended to the group who smoked 10 or less cigarettes per day, when total urinary recovery values were corrected for creatinine clearance. CONCLUSIONS: While BoE clearly differentiate between groups based on self-declared smoking status, most BoPH examined could not do so in a consistent manner. The dynamics of BoPH levels are not well understood. Future studies of BoPH should eliminate potential confounding factors and increase the number of subjects to allow the investigation of genetic polymorphism in metabolic pathways.

A prospectively measured serum biomarker for a tobacco-specific carcinogen and lung cancer in smokers.

BACKGROUND: No prior studies have related a tobacco-specific carcinogen to the risk of lung cancer in smokers. Of the over 60 known carcinogens in cigarette smoke, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is specific to tobacco and causes lung cancer in laboratory animals. Its metabolites, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol and its glucuronides (total NNAL), have been studied as biomarkers of exposure to NNK. We studied the relation of prospectively measured NNK biomarkers to lung cancer risk. METHODS: In a case-control study nested in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial, we randomly selected 100 lung cancer cases and 100 controls who smoked at baseline and analyzed their baseline serum for total NNAL, cotinine, and r-1,t-2,3,c-4-tetrahydroxy-1,2,3,4-tetrahydrophenanthrene (PheT), a biomarker of polycyclic aromatic hydrocarbon exposure and metabolic activation. To examine the association of the biomarkers with all lung cancers and for histologic subtypes, we computed odds ratios for total NNAL, PheT, and cotinine using logistic regression to adjust for potential confounders. FINDINGS: Individual associations of age, smoking duration, and total NNAL with lung cancer risk were statistically significant. After adjustment, total NNAL was the only biomarker significantly associated with risk (odds ratio, 1.57 per unit SD increase; 95% confidence interval, 1.08-2.28). A similar statistically significant result was obtained for adenocarcinoma risk, but not for nonadenocarcinoma. CONCLUSIONS: This first reporting of the effect of the prospectively measured tobacco-specific biomarker total NNAL, on risk of lung cancer in smokers provides insight into the etiology of smoking-related lung cancer and reinforces targeting NNK for cancer prevention.

Potential reduced exposure products (PREPs) for smokeless tobacco users: clinical evaluation methodology.

Several potential reduced exposure products (PREPs) for smokeless tobacco (SLT) users are marketed in the United States, though their effects are largely unknown. These products include some that are low in tobacco-specific nitrosamines (TSNs), like Stonewall, a pressed tobacco tablet, and General snus, a moist snuff product produced in Sweden. Methodology assessing the toxicant exposure and effects of cigarette-like PREPs for smokers has been developed, and might be modified for use in evaluating PREPs for SLT users. This report describes two studies examining the toxicant exposure and effects of two PREPs for SLT users. Study 1 (n = 13) consisted of four 4.5-hr laboratory sessions where SLT products (own brand, Stonewall, General snus, and tobacco-free placebo) were used for four 30-min episodes and nicotine exposure and tobacco/nicotine abstinence symptoms were measured. Study 2 (n = 19) consisted of four 5-day ad libitum use periods when participants used own brand, Stonewall, General snus, or no SLT and urinary levels of metabolites of nicotine (cotinine) and the TSN 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNAL) and abstinence symptoms were measured. Compared with own brand, Stonewall was associated with lower levels of cotinine and NNAL, while General snus was associated with similar levels of cotinine and lower levels of NNAL. Abstinence symptoms generally did not differ across tobacco conditions. These results show that clinical laboratory methods can be used to evaluate the toxicant exposure and abstinence symptom suppression associated with PREPs for SLT users.

Smoking reduction fails to improve clinical and biological markers of cardiac disease: a randomized controlled trial.

Cigarette reduction has been proposed as a treatment goal for smokers who are not interested in stopping completely. This randomized controlled trial was designed to determine the effect of a smoking reduction intervention on smoking behavior, symptoms of heart disease, and biomarkers of tobacco exposure. It included 152 patients with heart disease who did not intend to stop smoking in the next 30 days. Participants were randomly assigned to smoking reduction (SR) or usual care (UC). SR subjects received counseling and nicotine replacement therapy to encourage > or =50% reduction in cigarettes per day (CPD). They were followed at 1, 3, 6, 12 and 18 months to assess smoking, heart disease symptoms, quality of life and nicotine, cotinine, carbon monoxide (CO), white blood cell (WBC) count, fibrinogen, hs-C-reactive protein (hs-CRP), F2-isoprostane, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol and its glucuronides (total NNAL), and 1-hydroxypyrene (1-HOP). At 6 months SR participants reduced by 10.9 CPD, compared with 7.4 CPD in UC (difference NS). At 18 months, 9/78 SR vs. 9/74 UC participants quit smoking. There were no significant differences between treatment groups in angina, quality of life or adverse events, nicotine, cotinine, CO, WBC count, fibrinogen, hs-CRP, F2-isoprostane, total NNAL or 1-HOP levels at any time point. To determine if smoking reduction, regardless of treatment condition, was associated with improved outcomes, we compared all subjects at 6 months to baseline (mean reduction in CPD from 27.4 to 18.1, p<.01). There were no significant changes in outcome variables except CO, which decreased by 5.5 ppm (p<.01). There were also no significant improvements considering only subjects who reduced by > or =50%, or those who had no history of reduction prior to enrollment in the study. The SR intervention did not significantly reduce CPD or toxin exposure, or improve smoking cessation or clinical outcomes compared to UC. These results emphasize the importance of abstinence for smokers with heart disease to minimize health risks from tobacco.

Relationship of human toenail nicotine, cotinine, and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol to levels of these biomarkers in plasma and urine.

Recently, we developed sensitive and quantitative methods for analysis of the biomarkers of tobacco smoke exposure nicotine, cotinine, and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) in human toenails. In this study, we further evaluated the newly developed toenail biomarkers by investigating their relationship to demographic factors, reported exposure, plasma nicotine, cotinine, and trans-3'-hydroxycotinine, and urinary NNAL. Toenails of 105 smokers, mean age 38.9 years (range, 19-68), were analyzed. Fifty-five (53.4%) were male, with approximately equal numbers of Whites and African-Americans. The average number of cigarettes smoked per day was 18 (range, 5-50). There was no effect of age or gender on the toenail biomarkers. Toenail NNAL was higher in White than in African-American participants (P = 0.019). Toenail nicotine and toenail cotinine correlated significantly with cigarettes smoked per day (r = 0.24; P = 0.015 and r = 0.26; P = 0.009, respectively). Toenail nicotine correlated with plasma nicotine (r = 0.39; P < 0.001); toenail cotinine correlated with plasma cotinine (r = 0.45; P < 0.001) and plasma trans-3'-hydroxycotinine (r = 0.30; P = 0.008); and toenail NNAL correlated with urine NNAL (r = 0.53; P = 0.005). The results of this study provide essential validation data for the use of toenail biomarkers in investigations of the role of chronic tobacco smoke exposure in human cancer.

Effects of high dose transdermal nicotine replacement in cigarette smokers.

RATIONALE: Nicotine replacement therapies (NRT) have been evaluated to facilitate cigarette smoking reduction in smokers unwilling or unable to quit. In most of these studies, only conventional doses of NRT have been tested and higher doses may be required to result in significant reductions in smoking and in biomarkers of exposure. OBJECTIVE: To determine if higher NRT doses in conjunction with smoking are safe and may promote significant reductions in cigarette smoking and biomarkers of exposure. METHODS: A dose-ranging, within-subject design was implemented to evaluate the effects of 15, 30 and 45 mg nicotine-patch treatment on measures of safety and the extent of smoking reduction and biomarker exposure per cigarette in smokers (N=20 completers) not immediately interested in quitting. RESULTS: Concurrent smoking and NRT were generally tolerated and resulted in no changes in blood pressure or heart rate. Slightly less than 10% of the study sample was not given the highest dose of NRT due to side effects. Self-reported cigarette smoking decreased with increasing doses of nicotine replacement and significant reductions were observed for total NNAL (a carcinogen biomarker) and carbon monoxide. However, even at the 45 mg dose, increased carbon monoxide and total NNAL per cigarette occurred, even though cotinine levels increased on average, 69.3% from baseline. CONCLUSIONS: The present results suggest that the use of high dose NRT is safe, leads to significant reductions in smoking (-49%), significant but less reductions in total NNAL (-24%) and carbon monoxide (-37%) due to compensatory smoking.

Effects of type of smoking (pipe, cigars or cigarettes) on biological indices of tobacco exposure and toxicity.

Although all forms of smoking are harmful, smoking pipes or cigars is associated with lower exposure to the lethal products of tobacco products and lower levels of morbidity and mortality than smoking cigarettes. Cytochrome P-450-1A (CYP1A) is a major pathway activating carcinogens from tobacco smoke. Our primary aim was to compare CYP1A2 activity in individuals smoking pipes or cigars only, cigarettes only and in non-smokers. We studied 30 smokers of pipes or cigars only, 28 smokers of cigarettes only, and 30 non-smokers male subjects matched for age. CYP1A2 activity was assessed as the caffeine metabolic ratio in plasma. One-day urine collection was used for determining exposure to products of tobacco metabolism. Nitrosamine and benzo[a]pyrene DNA adducts were measured in lymphocytes. CYP1A2 activity was greater (p<0.0001) in cigarette smokers (median: 0.61; interquartile range: 0.52-0.76) than in pipe or cigar smokers (0.27; 0.21-0.37) and non-smokers (0.34; 0.25-0.42) who did not differ significantly. Urinary cotinine and 1-hydroxypyrene levels were higher in cigarette smokers than in pipe or cigar smokers and higher in the later than in non-smokers. DNA adducts levels were significantly lower in pipe or cigar smokers than in cigarette smokers. In multivariate analysis, cigarette smoking was the only independent predictor of CYP1A2 activity (p<0.0001) and of 1-hydroxypyrene excretion in urine (p=0.0012). In this study, pipe or cigar smoking was associated with lower exposure to products of tobacco metabolism than cigarette smoking and to an absence of CYP1A2 induction. Cigarette smoking was the only independent predictor of CYP1A2 activity in smokers. However, inhalation behaviour, rather than the type of tobacco smoked, may be the key factor linked to the extent of tobacco exposure and CYP1A2 induction. Our results provide a reasonable explanation for the results of epidemiological studies showing pipe or cigar smoking to present fewer health hazards than cigarette smoking.

Combined analysis of r-1,t-2,3,c-4-tetrahydroxy-1,2,3,4-tetrahydrophenanthrene and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol in smokers' plasma.

Polycyclic aromatic hydrocarbons (PAH) and tobacco-specific nitrosamines, such as 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), are widely accepted to be two important types of lung carcinogens in cigarette smoke. In this study, we have developed a method to estimate individual uptake of these compounds by quantifying r-1,t-2,3,c-4-tetrahydroxy-1,2,3,4-tetrahydrophenanthrene (PheT) and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) in 1 mL of smokers' plasma. PheT and NNAL are biomarkers of PAH and NNK uptake, respectively. [D10]PheT and [pyridine-D4]NNAL were added to plasma as internal standards. The plasma was treated with beta-glucuronidase to release any conjugated PheT and NNAL. The analytes were enriched by solid-phase extraction on a mixed mode cation exchange cartridge and the PheT fraction was further purified by high-performance liquid chromatography. The appropriate fractions were analyzed by gas chromatography-negative ion chemical ionization-mass spectrometry for PheT and liquid chromatography-electrospray ionization-mass spectrometry for NNAL. The method was sensitive (limits of quantitation: PheT, 13 fmol/mL; NNAL, 3 fmol/mL), accurate, and precise. Levels of PheT and NNAL in plasma from 16 smokers averaged 95 +/- 71 and 36 +/- 21 fmol/mL, respectively, which are approximately 1% to 2% of the amounts found in urine. This method should be useful in molecular epidemiology studies of carcinogen uptake and lung cancer in smokers.