Increased di-(2-ethylhexyl) phthalate exposure poses a differential risk for adult asthma clusters.

BACKGROUND: DEHP, a common plasticizer known for its hormone-disrupting properties, has been associated with asthma. However, a significant proportion of adult asthma cases are "non-atopic", lacking a clear etiology. METHODS: In a case-control study conducted between 2011 and 2015, 365 individuals with current asthma and 235 healthy controls from Kaohsiung City were enrolled. The control group comprised individuals without asthma, Type 2 Diabetes Mellitus (T2DM), hypertension, or other respiratory/allergic conditions. The study leveraged asthma clusters (Clusters A to F) established in a prior investigation. Analysis involved the examination of urinary DEHP metabolites (MEHP and MEHHP), along with the assessment of oxidative stress, sphingolipid metabolites, and inflammatory biomarkers. Statistical analyses encompassed Spearman's rank correlation coefficients, multiple logistic regression, and multinomial logistic regression. RESULTS: Asthma clusters (E, D, C, F, A) exhibited significantly higher ORs of MEHHP exposures compared to the control group. When considering asthma-related comorbidities (T2DM, hypertension, or both), patients without comorbidities demonstrated significantly higher ORs of the sum of primary and secondary metabolites (MEHP + MEHHP) and MEHHP compared to those with asthma comorbidities. A consistent positive correlation between urinary HEL and DEHP metabolites was observed, but a consistent negative correlation between DEHP metabolites and selected cytokines was identified. CONCLUSION: The current study reveals a heightened risk of MEHHP and MEHP + MEHHP exposure in specific asthma subgroups, emphasizing its complex relationship with asthma. The observed negative correlation with cytokines suggests a new avenue for research, warranting robust evidence from epidemiological and animal studies.

Environmental risks and sphingolipid signatures in adult asthma and its phenotypic clusters: a multicentre study.

BACKGROUND: Adult asthma is phenotypically heterogeneous with unclear aetiology. We aimed to evaluate the potential contribution of environmental exposure and its ensuing response to asthma and its heterogeneity. METHODS: Environmental risk was evaluated by assessing the records of National Health Insurance Research Database (NHIRD) and residence-based air pollution (particulate matter with diameter less than 2.5 micrometers (PM2.5) and PM2.5-bound polycyclic aromatic hydrocarbons (PAHs)), integrating biomonitoring analysis of environmental pollutants, inflammatory markers and sphingolipid metabolites in case-control populations with mass spectrometry and ELISA. Phenotypic clustering was evaluated by t-distributed stochastic neighbor embedding (t-SNE) integrating 18 clinical and demographic variables. FINDINGS: In the NHIRD dataset, modest increase in the relative risk with time-lag effect for emergency (N=209 837) and outpatient visits (N=638 538) was observed with increasing levels of PM2.5 and PAHs. Biomonitoring analysis revealed a panel of metals and organic pollutants, particularly metal Ni and PAH, posing a significant risk for current asthma (ORs=1.28-3.48) and its severity, correlating with the level of oxidative stress markers, notably Nε-(hexanoyl)-lysine (r=0.108-0.311, p<0.05), but not with the accumulated levels of PM2.5 exposure. Further, levels of circulating sphingosine-1-phosphate and ceramide-1-phosphate were found to discriminate asthma (p<0.001 and p<0.05, respectively), correlating with the levels of PAH (r=0.196, p<0.01) and metal exposure (r=0.202-0.323, p<0.05), respectively, and both correlating with circulating inflammatory markers (r=0.186-0.427, p<0.01). Analysis of six phenotypic clusters and those cases with comorbid type 2 diabetes mellitus (T2DM) revealed cluster-selective environmental risks and biosignatures. INTERPRETATION: These results suggest the potential contribution of environmental factors from multiple sources, their ensuing oxidative stress and sphingolipid remodeling to adult asthma and its phenotypic heterogeneity.

Simultaneous determination of eight ß-adrenergic agonists in human urine by an isotope dilution-online clean-up system coupled with liquid chromatography-tandem mass spectrometry.

ß-Adrenergic agonist compounds are medicines that open up the lung's medium and large airways. ß-Adrenergic agonist compounds have been illegally or legally used to increase lean muscle mass in meat animals, bodybuilding, weight-loss programs, and athletes. Developing a rapid analytical approach for determining ß-adrenergic agonist compounds in biological samples is crucial for individual exposure assessment. This study established an analytical method for simultaneously measuring eight ß-adrenergic agonist compounds in human urine, including clenbuterol, terbutaline, salbutamol, ractopamine, zilpaterol, cimaterol, tulobuterol, and fenoterol. Two hundred microliters of a urine sample were added to eight deuterium-labeled internal standard mixtures and glucuronidase/arylsulfatase for enzymatic hydrolysis, and were then analyzed using an online clean-up system coupled with a liquid chromatography-tandem mass spectrometry system (LC-MS/MS). The limit of quantification ranged from 0.03 to 0.12 ng/mL urine for the eight ß-adrenergic agonist compounds. The relative standard deviations (RSD) of the within-run and between-run precisions were less than 10%, and the relative accuracy errors were less than 17% in the three-level spiked artificial urine samples. Two hundred eighty human urine samples collected from the general population in Taiwan were assessed to demonstrate the capability and feasibility of this method. The detection frequencies were 33% for clenbuterol, 5% for ractopamine, and less than 5% for the others. We concluded that the isotope dilution-online clean-up system coupled with LC-MS/MS method is a valuable analytical method for investigating urinary ß-adrenergic agonist compounds in humans and is valuable for human biomonitoring studies.

Prenatal and childhood phthalate exposure and attention deficit hyperactivity disorder traits in child temperament: A 12-year follow-up birth cohort study.

Temperamental tendencies may form the basis of personality development, and specific personality constellations are associated with increased incidences of behavioural problems. Phthalic acid ester (PAE) has been associated with symptoms of attention deficit hyperactivity disorder (ADHD) in cross-sectional studies. We hypothesised that early-life exposure to PAE affects the temperaments of children, particularly ADHD traits. In this study, we analysed the temperament evaluations completed at least once by maternal-infant pairs (n = 208) when the child was aged 2, 5, and/or 11 years between 2000 and 2012. We measured seven PAE metabolites in the urine of the mothers during pregnancy and their children using liquid chromatography-electrospray ionisation-tandem mass spectrometry. These metabolites included mono-methyl phthalate, mono-ethyl phthalate, mono-butyl phthalate (MBP), mono-benzyl phthalate (MBzP), and three metabolites of di (2-ethylhexyl) phthalate. The phthalate metabolite levels in pregnant women were significantly associated with a decreased threshold of responsiveness (coefficients from -0.21 to -0.46) and increased distractibility (coefficients from 0.23 to 0.46) in pre-school children. After adjustment for maternal exposure, the phthalate metabolite concentrations of the children exhibited significantly increased odds ratios (ORs) with respect to the ADHD symptom traits. Specifically, mono-2-ethyl-5-hydroxyhexyl phthalate (MEHHP), the sum of the DEHP metabolites, and MBzP yielded ORs and 95% confidence intervals of 2.98 (1.05-8.48), 3.28 (1.15-9.35), and 9.12 (1.07-78.06), respectively, for every log10 creatinine unit (g/g creatinine) increase. Thus, early-life phthalate exposure was found to be associated with the behavioural characteristics of children, particularly temperamental traits associated with ADHD.

Environmental Factor-Mediated Transgenerational Inheritance of Igf2r Hypomethylation and Pulmonary Allergic Response via Targeting Dendritic Cells.

The developmental origin of allergic diseases has been suggested, but the molecular basis remains enigmatic. Exposure to environmental factors, such as di-(2-ethylhexyl) phthalate (DEHP; a common plasticizer), is suggested to be associated with increased childhood allergic asthma, but the causal relationship and its underlying mechanism remain unknown. This study explored the transgenerational mechanism of DEHP on allergic asthma and dendritic cell (DC) homeostasis through epigenetic modification. In a murine model, ancestral exposure of C57BL/6 mice to low-dose DEHP led to trans-generational promoter hypomethylation of the insulin-like growth factor 2 receptor (Igf2r), concomitant with enhanced Igf2r expression and increased apoptosis prominently in CD8α+ DCs upon ligand stimulation, with consequent reduction in their IL-12 secretion and subsequent T cell-derived IFN-γ, thereby promoting a default Th2-associated pulmonary allergic response. Increased apoptosis was also noted in circulating IGF2Rhigh human DCs. Further, in human placenta, the methylation level at the orthologous IGF2R promoter region was shown to be inversely correlated with the level of maternal DEHP intake. These results support the importance of ancestral phthalate exposure in conferring the trans-generational risk of allergic phenotypes, featuring hypo-methylation of the IGF2R gene and dysregulated DC homeostasis.

A prominent air pollutant, Indeno[1,2,3-cd]pyrene, enhances allergic lung inflammation via aryl hydrocarbon receptor.

Chronic exposure to ambient polycyclic aromatic hydrocarbons (PAHs) is associated with asthma, but its regulatory mechanisms remain incompletely defined. We report herein that elevated levels of urinary 1-hydroxypyrene, a biomarker of PAH exposure, were found in asthmatic subjects (n = 39) as compared to those in healthy subjects (n = 43) living in an industrial city of Taiwan, where indeno[1,2,3-cd]pyrene (IP) was found to be a prominent PAH associated with ambient PM2.5. In a mouse model, intranasal exposure of mice with varying doses of IP significantly enhanced antigen-induced allergic inflammation, including increased airway eosinophilia, Th2 cytokines, including IL-4 and IL-5, as well as antigen-specific IgE level, which was absent in dendritic cell (DC)-specific aryl hydrocarbon receptor (AhR)-null mice. Mechanistically, IP treatment significantly altered DC's function, including increased level of pro-inflammatory IL-6 and decreased generation of anti-inflammatory IL-10. The IP's effect was lost in DCs from mice carrying an AhR-mutant allele. Taken together, these results suggest that chronic exposure to environmental PAHs may pose a significant risk for asthma, in which IP, a prominent ambient PAH in Taiwan, was shown to enhance the severity of allergic lung inflammation in mice through, at least in part, its ability in modulating DC's function in an AhR-dependent manner.

Prenatal and Childhood Exposure to Phthalate Diesters and Thyroid Function in a 9-Year Follow-up Birth Cohort Study: Taiwan Maternal and Infant Cohort Study.

BACKGROUND: Phthalates are widely used in industry, personal care products, and medications. Recent studies have suggested that phthalate exposure alters thyroid hormones. However, longitudinal studies concerning the association between phthalate exposure and thyroid function in children are scant. Therefore, we examined the association between pre- and postnatal phthalate exposure and thyroid function in children born in 2000-2001. METHODS: We studied 181 mother-child pairs in central Taiwan and followed-up the children from 2000 to 2009 at 2, 5, and 8 years old. We measured serum levels of thyroxine (T4), free T4, triiodothyronine (T3), and thyroid-stimulating hormone in children by using radioimmunoassay. We quantified seven phthalate metabolites, representing the five most commonly used phthalates, in maternal and child urine samples by using liquid chromatography-tandem mass spectrometry. The metabolites were monoethylhexyl phthalate (MEHP), mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP) derived from di(2-ethylhexyl) phthalate (DEHP), monomethyl phthalate (MMP), monoethyl phthalate (MEP), monobutyl phthalate (MBP), and monobenzyl phthalate (MBzP). We constructed a linear mixed model to examine these associations after adjustments for covariates. RESULTS: The T4 levels were inversely associated with maternal urinary MEHHP (ß = -0.028 [95% confidence interval (CI) = -0.051, -0.006]) and MEOHP (ß = -0.027 [-0.050, -0.003]), with similar T3 levels being observed in boys, even when the children exposure levels were considered spontaneously. In the girls, the free T4 levels were inversely associated with levels of maternal urinary MEP (ß = -0.042), maternal urinary MBzP (ß = -0.050), and children's urinary MEHP (ß = -0.027). CONCLUSIONS: Early life phthalate exposure was associated with decreased thyroid hormone levels in young children.

Increased levels of oxidative stress biomarkers in metal oxides nanomaterial-handling workers.

This study assessed oxidatively damaged DNA and antioxidant enzyme activity in workers occupational exposure to metal oxides nanomaterials. Exposure to TiO2, SiO2, and ITO resulted in significant lower antioxidant enzymes (glutathione peroxidase and superoxide dismutase) and higher oxidative biomarkers 8-hydroxydeoxyguanosine (8-oxodG) than comparison workers. Statistically significant correlations were noted between plasma and urine 8-oxodG, between white blood cells (WBC) and urine 8-oxodG, and between WBC and plasma 8-oxodG. In addition, there were significant negative correlations between WBC 8-oxodG and SOD and between urinary 8-oxodG and GPx levels. The results showed that urinary 8-oxodG may be considered to be better biomarker.

Fetal and Childhood Exposure to Phthalate Diesters and Cognitive Function in Children Up to 12 Years of Age: Taiwanese Maternal and Infant Cohort Study.

Few studies have examined the association between environmental phthalate exposure and children's neurocognitive development. This longitudinal study examined cognitive function in relation to pre-and postnatal phthalate exposure in children 2-12 years old. We recruited 430 pregnant women in their third trimester in Taichung, Taiwan from 2001-2002. A total of 110, 79, 76, and 73 children were followed up at ages 2, 5, 8, and 11, respectively. We evaluated the children's cognitive function at four different time points using the Bayley and Wechsler tests for assessing neurocognitive functions and intelligence (IQ). Urine samples were collected from mothers during pregnancy and from children at each follow-up visit. They were analyzed for seven metabolite concentrations of widely used phthalate esters. These esters included monomethyl phthalate, monoethyl phthalate, mono-butyl phthalate, mono-benzyl phthalate, and three metabolites of di(2-ethylhexyl) phthalate, namely, mono-2-ethylhexyl phthalate, mono(2-ethyl-5-hydroxyhexyl) phthalate, and mono(2-ethyl-5-oxohexyl) phthalate. We constructed a linear mixed model to examine the relationships between the phthalate metabolite concentrations and the Bayley and IQ scores. We found significant inverse associations between the children's levels of urinary mono(2-ethyl-5-oxohexyl) phthalate and the sum of the three metabolites of di(2-ethylhexyl) phthalate and their IQ scores (ß = -1.818; 95% CI: -3.061, -0.574, p = 0.004 for mono(2-ethyl-5-oxohexyl) phthalate; ß = -1.575; 95% CI: -3.037, -0.113, p = 0.035 for the sum of the three metabolites) after controlling for maternal phthalate levels and potential confounders. We did not observe significant associations between maternal phthalate exposure and the children's IQ scores. Children's but not prenatal phthalate exposure was associated with decreased cognitive development in the young children. Large-scale prospective cohort studies are needed to confirm these findings in the future.

Prenatal and postnatal exposure to phthalate esters and asthma: a 9-year follow-up study of a taiwanese birth cohort.

Previous studies have shown that phthalate exposure in childhood is associated with the development of respiratory problems. However, few studies have assessed the relative impact of prenatal and postnatal exposure to phthalates on the development of asthma later in childhood. Therefore, we assessed the impact of prenatal and postnatal phthalate exposure on the development of asthma and wheezing using a Taiwanese birth cohort. A total of 430 pregnant women were recruited, and 171 (39.8%) of them had their children followed when they were aged 2, 5, and 8 years. The International Study of Asthma and Allergies in Childhood questionnaire was used to assess asthma and wheezing symptoms and serum total immunoglobulin E levels were measured at 8 years of age. Urine samples were obtained from 136 women during their third trimester of pregnancy, 99 children at 2 years of age, and 110 children at 5 years. Four common phthalate monoester metabolites in maternal and children's urine were measured using liquid chromatography-electrospray ionization-tandem mass spectrometry. Maternal urinary mono-benzyl phthalate [MBzP] concentrations were associated with an increased occurrence of wheezing in boys at 8 years of age (odds ratio [OR] = 4.95 (95% CI 1.08-22.63)), for upper quintile compared to the others) after controlling for parental allergies and family members' smoking status. Urinary mono-2-ethylhexyl phthalate [MEHP] levels over the quintile at 2-year-old were associated with increased asthma occurrence (adjusted OR = 6.14 (1.17-32.13)) in boys. Similarly, the sum of di-2-ethyl-hexyl phthalate [DEHP] metabolites at 5 years was associated with asthma in boys (adjusted OR = 4.36 (1.01-18.86)). Urinary MEHP in maternal and 5-year-old children urine were significantly associated with increased IgE in allergic children at 8 years. Prenatal and postnatal exposure to phthalate was associated with the occurrence of asthma in children, particularly for boys.

Assessment of the potential of polyphenols as a CYP17 inhibitor free of adverse corticosteroid elevation.

Inhibition of 17α-hydroxylase/17,20-lyase (CYP17), which dictates the proceeding of androgen biosynthesis, is recommended as an effective treatment for androgen-dependent diseases. However, androgen depletion by selective CYP17 inhibition is accompanied with corticosteroid elevation, which increases risk of cardiovascular diseases. In this study, we evaluated the likelihood of polyphenols as a CYP17 inhibitor without cardiovascular complications. All examined polyphenols significantly inhibited CYP17 in human adrenocortical H295R cells, but their effects on androgen and cortisol biosynthesis were diverse. Resveratrol was the most potent CYP17 inhibitor with an approximate IC50 of 4 µM, and the inhibition might weigh on the 17α-hydroxylase activity more than the 17,20-lyase activity. Resveratrol also inhibited 21α-hydroxylase (CYP21) essential for corticosteroid biosynthesis but to a lesser extent, thus preventing the occurrence of cortisol elevation following CYP17 blockade. Although transcriptional down-regulation was important for α-naphthoflavone-mediated CYP17 inhibition, resveratrol inhibited CYP17 and CYP21 mainly at the level of enzyme activity rather than enzyme abundance and cytochrome P450 electron transfer. Daidzein also inhibited CYP17 and CYP21 although less potent than resveratrol. Daidzein was the only polyphenol showing inhibition of 3ß-hydroxysteroid dehydrogenase type II (3ßHSD2). The exceptional 3ßHSD2 inhibition led to dehydroepiandrosterone accumulation alongside daidzein-caused androgen biosynthetic impairment. In contrast, androgen and cortisol secretion was increased or remained normal under α-naphthoflavone and ß-naphthoflavone treatments, suggesting that CYP17 inhibition was counteracted by increased substrate generation. α-naphthoflavone and ß-naphthoflavone also enhanced the formation of cortisol from 17-hydroxyprogesterone and testosterone from androstenedione. Our findings suggest a potential application of resveratrol in androgen deprivation therapy.

Maternal arsenic exposure and DNA damage biomarkers, and the associations with birth outcomes in a general population from Taiwan.

Inorganic arsenic (iAs) is an established transplacental agent known to affect fetal development in animal studies. However, iAs has not been adequately studied in the general population with respect to iAs exposure during pregnancy and its impact on the health status of newborns. The aims of this study were to 1) elucidate the association between arsenic exposure and oxidative/methylated DNA damage in pregnant women, and 2) determine the association with birth outcomes. A birth cohort study of 299 pregnant mother-newborn pairs was recruited during 2001-2002 in Taiwan. We collected maternal urine samples during the 3(rd) trimester for measuring iAs and its metabolites. We used high-performance liquid chromatography/inductively coupled plasma mass spectrometry (HPLC-ICP-MS) for quantifications of the arsenic species. Liquid chromatography/tandem mass spectrometer (LC-MS/MS) was used to measure the 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) and N(7)-methylguanosine (N(7)-MeG) DNA damage biomarkers. Birth outcomes were collected to assess the associations with maternal arsenic exposure and the DNA damage biomarkers. Multiple regression analyses showed that maternal urinary iAs had positive associations with the methylated N(7)-MeG (beta = 0.35, p<0.001) and oxidative 8-oxodG (beta = 0.24, p<0.001) DNA damage biomarkers, and a decreased one-minute (1-min) Apgar score (beta = -0.23, p = 0.041). Maternal N(7)-MeG was also associated with a decreased 1-min Apgar score (beta = -0.25, p = 0.042). Mutual adjustment for iAs and N(7)-MeG showed an independent and significant prediction for a decreased 1-min Apgar score of iAs (beta = -0.28, p = 0.036). Maternal iAs exposure was associated with both maternal DNA damage and adverse newborn health. Maternal N(7)-MeG levels might be a novel biomarker for monitoring fetal health related to iAs.

Exposure to heavy metals and polycyclic aromatic hydrocarbons and DNA damage in taiwanese traffic conductors.

BACKGROUND: Exposure to traffic-related air pollutants, including polycyclic aromatic hydrocarbons (PAH) and heavy metals, has been associated with the etiology and prognosis of many illnesses. However, the specific causal agents and underlying mechanisms for different health outcomes remain unclear. The aims of this study were to assess the relations between urinary biomarkers of exposure to PAHs (1-hydroxypyrene-glucuronide, 1-OHPG) and heavy metals (cadmium, Cd; nickel, Ni; arsenic, As; lead, Pb; and copper, Cu) and the effect of their interaction on DNA damage (8-oxo-7,8-dihydro-guanine, 8-oxodG). METHODS: We recruited 91 traffic conductors and 53 indoor office workers between May 2009 and June 2011 in Taipei, Taiwan. Postshift urine samples from 2 consecutive days were analyzed for 1-OHPG, Cd, Ni, As, Pb, Cu, and 8-oxodG. To estimate the effects from PAHs and metals on DNA damage, we constructed a linear mixed model adjusted for confounding variables. RESULTS: We found that urinary 1-OHPG and Cd levels were independent predictors of urinary 8-oxodG levels (ß = 0.112; P = 0.015 for 1-OHPG; ß = 0.138; P = 0.031 for urinary Cd). The joint effect of urinary 1-OHPG and Cd levels was associated with urinary 8-oxodG levels (P = 0.001). CONCLUSIONS: Co-exposure to environmental PAHs and Cd could cause oxidative DNA damage. IMPACT: These findings suggest that the additive interaction between exposure to environmental PAHs and Cd could enhance the burden of oxidative stress.

Heat acclimation decreased oxidative DNA damage resulting from exposure to high heat in an occupational setting.

Heat acclimation is a physiologically and biochemically adapted process when species transition from one environmental temperature to one of the increased temperature. There is very limited epidemiological evidence on the heat-related impacts during exposure to extremely high heat in an occupational environment. This study sought to identify a potential biomarker of heat acclimation and the burden of heat on the body. The aim of this study was to elucidate oxidative DNA damage and heat acclimation through a self-comparison study design in navy boiler tenders, subjects exposed to extremely high heat in an occupational setting. Fifty-eight male soldiers who work in a boiler room were recruited for this study. The subjects were initially assessed with a health examination and body composition assessment before sailing. In order to compare the within-subject differences before and after heat exposure, the index-related heat exposure was collected before and after a routine 5-h work shift and 7-day sailing. Urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG), a useful marker of oxidative DNA damage was the measurement by liquid chromatography/tandem mass spectrometry. The median of the change in urinary 8-OHdG was 0.78 µg/g creatinine, as the urinary 8-OHdG after sailing was significantly higher than before sailing (p < 0.01). The urinary 8-OHdG was significantly decreased in heat-acclimated boiler tenders. Oxidative DNA damage was significantly decreased in heat-acclimated subjects. Urinary 8-OHdG can be used as a biomarker to assess the effect of heat stress as a result of occupational exposure to extremely high heat conditions.

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.

Rapid and simple one-step membrane extraction for the determination of 8-hydroxy-2'-deoxyguanosine in human plasma by a combination of on-line solid phase extraction and LC-MS/MS.

A quantitative analytical method using automated on-line solid phase extraction (SPE) and liquid chromatography-electrospray tandem mass spectrometry (LC-ESI-MS/MS) for the determination of 8-OHdG (8-hydroxy-2'-deoxyguanosine) in human plasma was developed and validated. A one-step membrane extraction method for the plasma sample preparation and a C18 SPE column with simple extraction and purification were used for the on-line extraction. A C18 column was employed for LC separation and ESI-MS/MS was utilized for detection. (15)N(5)-8-OHdG ((15)N(5)-8-hydroxy-2'-deoxyguanosine) was used as an internal standard for quantitative determination. The extraction, clean-up and analysis procedures were controlled by a fully automated six-port switch valve as one strategy to reduce the matrix effect and simultaneously improve detection sensitivity. Identification and quantification were based on the following transitions: m/z 284→168 for 8-OHdG and m/z 289→173 for (15)N(5)-8-OHdG. Satisfactory recovery was obtained, and the recovery ranged from 95.1 to 106.1% at trace levels in human plasma and urine, with a CV lower than 5.4%. Values for intraday and interday precision were between 2.3 and 6.8% for plasma and between 2.7 and 4.5% for urine, respectively. Values for the method accuracy of intraday and interday assays ranged from 93.0 and 100.5% for plasma and 110.2 and 119.4% for urine, respectively. The limits of detection (LOD) and LOQ were 0.008 ng/mL and 0.02 ng/mL, respectively.The applicability of this newly developed method was demonstrated by analysis of human plasma samples for an evaluation of the future risk of oxidative stress status in human exposure to nanoparticles and other diseases.

Cd/Se/Te-based quantum dot 705 modulated redox homeostasis with hepatotoxicity in mice.

The objective of this study was to investigate whether quantum dot 705 (QD705) disrupts the cellular antioxidant systems leading to hepatotoxicity in mice. Mice were intravenously injected with QD705 and then sacrificed at week 12 or 16. Homeostasis of antioxidant-related metals, antioxidant activities, induction of oxidative stress, and toxicity in the liver were investigated. Although no histopathological change was observed, a time- and dose-dependent increase in metallothionein expression and reduction in liver function was noticed. Increased copper, zinc, and selenium levels and enhancements of the trace metal-corresponding transporters were noted at week 12. At week 16, a decline of selenium from its elevated level at week 12 was observed, which was accompanied by changes in glutathione peroxidase activity as well as in redox status. A significant reduction in superoxide dismutase activity was observed at 16 weeks. Furthermore, a corresponding elevation of heme oxygenase-1 expression, 8-oxo-7,8-dihydro-2'-deoxyguanosine, interleukin-6 and tumor necrosis factor-alpha suggested the presence of oxidative stress, oxidative DNA damage and inflammation.

Fast quantification of the exhaled breath condensate of oxidative stress 8-iso-prostaglandin F2alpha using on-line solid-phase extraction coupled with liquid chromatography/electrospray ionization mass spectrometry.

A method using automated on-line solid-phase extraction (SPE) liquid chromatography-electrospray tandem mass spectrometry (LC-ESI-MS/MS) for the determination of 8-iso-PGF2alpha in human exhaled breath condensate (EBC) was developed and validated. A C18 SPE column with an affinity sorbent was used for on-line extraction. A C18 column was employed for LC separation and ESI-MS/MS was utilized for detection. 8-iso-PGF2alpha-d(4) was used as an internal standard for quantitative determination. The extraction, cleanup and analysis procedures were controlled by a fully automated six-port switch valve. Identification and quantification were based on the following transitions: m/z 353-->193 for 8-iso-PGF2alpha and m/z 357-->197 for 8-iso-PGF2alpha-d(4), respectively. Good recoveries from 98.94 to 99.86% were measured and satisfactory linear ranges for these analytical compounds were determined. Intra-day and inter-day precision showed that coefficients of variance (CV) ranged from 6.5 to 8.0% and 5.2 to 6.3%, respectively. The applicability of this newly developed method was demonstrated by analyzing human EBC samples for an evaluation of the future risk of human exposure to nanoparticles.

Quantification of blood betel quid alkaloids and urinary 8-hydroxydeoxyguanosine in humans and their association with betel chewing habits.

Chewing betel quid is a common habit in Taiwan and associated with the risk of oral cancer. Betel quid contains arecoline and arecaidine, which may serve as the exposure biomarkers of a chewing habit. We developed a liquid chromatography-tandem mass spectrometry method for the quantitative analysis of blood arecoline and arecaidine. Because 8-hydroxydeoxyguanosine (8-OH-dG) level in urine is only one early health marker of carcinogenesis, we also examined its association with chewing habit. We found a significant positive correlation between the quantities of betel quid used before the day of drawing blood and arecoline [(Spearman correlation coefficient (r) = 0.81; p value < 0.01) or arecaidine levels (r = 0.86; p value < 0.01)]. Habitual use quantity (quids/day) showed moderate correlation with both arecoline (r = 0.52; p value < 0.05) and arecaidine concentrations (r = 0.51; p value < 0.05). However, there were no significant correlations between total chewing years and concentrations of arecoline and arecaidine in serum or 8-OH-dG in urine. In conclusion, serum arecoline and arecaidine levels are measurable and good indicators for recent betel quid use.