Urinary heavy metals and attention-deficit/hyperactivity symptoms of preschool children: a mixed-exposure analysis.

The neurotoxic effects of certain heavy metals are well established, but only a few studies have investigated the joint effect of concurrent exposure to multiple ones. The study aims to evaluate the association between mixed exposure to neurotoxic metals and the psychosocial behavior of preschool children. Using a stratified sampling strategy, we recruited participants from 105 kindergartens in 41 townships of Taiwan and excluded those with blood lead levels ≥ 3.5 µg/L. The first-morning void urines were collected and analyzed for cadmium, manganese, arsenic, chromium, lead, and nickel concentrations using inductively coupled plasma mass spectrometry. We applied the parentally reported Strengths and Difficulties Questionnaire (SDQ) and Swanson, Nolan, and Pelham IV (SNAP-IV) scales to evaluate the psychosocial behaviors. Multiple linear regressions were utilized to evaluate the associations between each heavy metal and the outcomes, while the mixed effect of concurrent exposure was estimated by using a Quantile g-computation approach. A total of 977 preschool children were included in the study, and the mean (SD) age was 5.7 (0.7) years old. In single pollutant models, we observed adverse effects of urinary manganese, nickel, arsenic, and lead on the specific subsets of SDQ. Furthermore, the combined effect of six heavy metals significantly affected the hyperactivity/inattention symptoms (beta = 0.46, 95% CI: 0.13-0.78, with all metals increased by one quartile), and chromium and lead were the two major contributors. Similar detrimental effects of urinary cadmium and lead were also observed in the SNAP-IV subsets, although the joint effect analysis was not significant. The study provided evidence that concurrent exposure to multiple heavy metals may exert increased risks of hyperactivity/inattention in children compared to single pollutant exposure. Further studies are needed to verify our findings regarding mixed exposure to multiple neurotoxic metals.

Untargeted metabolomics analysis assisted by signal selection for comprehensively identifying metabolites of new psychoactive substances: 4-MeO-α-PVP as an example.

New psychoactive substances (NPS) have been rapidly emerged as legal alternatives to controlled drugs, which raised severe public health issue. The detection and monitoring of its intake by complete metabolic profiling is an urgent and vital task. Untargeted metabolomics approach has been applied for several NPS metabolites studies. Although the number of such works is relatively limited but with a rapidly growing need. The present study aimed to propose a procedure that includes liquid chromatography high-resolution mass spectrometry (LC-HRMS) analysis and a signal selection software, MetaboFinder, programed as a web tool. The comprehensive metabolites profile of one kind of NPS, 4-methoxy-α-pyrrolidinovalerophenone (4-MeO-α-PVP), was studied by using this workflow. In this study, two different concentrations of 4-MeO-α-PVP along with as blank sample were incubated with human liver S9 fraction for the conversion to their metabolites and followed by LC-MS analysis. After retention time alignment and feature identification, 4640 features were obtained and submitted to statistical analysis for signal selection by using MetaboFinder. A total of 50 features were considered as 4-MeO-α-PVP metabolite candidates showing significant changes (p < 0.00001 and fold change >2) between the two investigated groups. Targeted LC-MS/MS analysis was conducted focusing on these significantly expressed features. Assisted by chemical formula determination according to high mass accuracy and in silico MS2 fragmentation prediction, 19 chemical structure identifications were achieved. Among which, 8 metabolites have been reported derived from 4-MeO-α-PVP in a previous literature while 11 novel 4-MeO-α-PVP metabolites were identified by using our strategy. Further in vivo animal experiment confirmed that 18 compounds were 4-MeO-α-PVP metabolites, which demonstrated the feasibility of our strategy for screening the 4-MeO-α-PVP metabolites. We anticipate that this procedure may support and facilitate traditional metabolism studies and potentially being applied for routine NPS metabolites screening.

Connecting chemical exposome to human health using high-resolution mass spectrometry-based biomonitoring: Recent advances and future perspectives.

Compared with the rapid advances in genomics leading to broad understanding of human disease, the linkage between chemical exposome and diseases is still under investigation. High-resolution mass spectrometry (HRMS) is expected to accelerate the process via relatively accurate and precise biomonitoring of human exposome. This review covers recent advancements in biomonitoring of exposed environmental chemicals (chemical exposome) using HRMS described in the 124 articles that resulted from a systematic literature search on Medline and Web of Science databases. The analytical strategic aspects, including the selection of specimens, sample preparation, instrumentation, untargeted versus targeted analysis, and workflows for MS-based biomonitoring to explore the environmental chemical space of human exposome, are deliberated. Applications of HRMS in human exposome investigation are presented by biomonitoring (1) exposed chemical compounds and their biotransformation products; (2) DNA/protein adducts; and (3) endogenous compound perturbations. Challenges and future perspectives are also discussed.

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.

Exploration of long-term exposure markers for phthalate esters in human hair using liquid chromatography-tandem mass spectrometry.

Phthalate esters are a group of synthetic industrial chemicals that are widely used in plastics. Urinary phthalate metabolites are short-term exposure markers frequently used to represent exposure levels in environmental epidemiology studies. Human hair is an alternative matrix for recording long-term exposure, but there are still analytical challenges that need to be addressed. In this study, an analytical method was established for simultaneously measuring nine major phthalate metabolites in human hair and successfully applied to measure phthalate metabolites in 30 hair samples collected from 30 individual human volunteers without known occupational exposure to phthalates. Two portions of 25 mg of hair samples were extracted by acidified methanol and water in 240 min of ultrasonication and then analyzed using a liquid chromatography-tandem mass spectrometry system. The limit of quantification ranged from 0.72 to 10.7 ng/g hair for nine phthalate metabolites. All nine phthalate metabolites were detected in more than 70% of the 30 individual human hair samples. The measured levels of hair phthalate metabolites were (in descending order): MEHP > MMP â‰« MEP > MBP (MnBP + MiBP) > MiNP > MEHHP ≈ MEOHP ≈ MECPP. The primary metabolite, MEHP (692 ± 582 ng/g), is the major DEHP metabolite in hair. This result is consistent with the findings in blood but not in urine, in which the secondary metabolites are the major DEHP metabolites. This method is easy to foresee with a clinical application and applies to human biomonitoring studies to assess long-term environmental phthalate exposure.

Identification of ambient fine particulate matter components related to vascular dysfunction by analyzing spatiotemporal variations.

Exposure to ambient fine particulate matter (PM2.5) has been associated with vascular diseases in epidemiological studies. We have demonstrated previously that exposure to ambient PM2.5 caused pulmonary vascular remodeling in mice and increased vascular smooth muscle cells (VSMCs) viability. Here, we further demonstrated that exposure of mice to ambient PM2.5 increased urinary 8­hydroxy­2'­deoxyguanosine (8-OHdG) and cytokines concentrations in the broncheoalveolar lavage. The objective of the present study was to identify the PM2.5 components related to vascular dysfunction. Exposure to PM2.5 collected from various areas and seasons in Taiwan significantly increased viability, oxidative stress, and inflammatory cytokines secretion in VSMCs. The mass concentrations of benz[a]anthracene (BaA), benzo[e]pyrene (BeP), perylene, dibenzo[a,e]pyrene, molybdenum, zinc (Zn), vanadium (V), and nickel in the PM2.5 were significantly associated with increased viability of VSMCs. These components, except BaA and BeP, also were significantly associated with chemokine (CC motif) ligand 5 (CCL5) concentrations in the VSMCs. The effects of V and Zn on cell viability and CCL5 expression, respectively, were verified. In addition, the mass concentrations of sulfate and manganese (Mn) in PM2.5 were significantly correlated with increased oxidative stress; this correlation was also confirmed. After extraction, the inorganic fraction of PM2.5 increased cell viability and oxidative stress, but the organic fraction of PM2.5 increased only cell viability, which was inhibited by an aryl hydrocarbon receptor antagonist. These data suggest that controlling the emission of Zn, V, Mn, sulfate, and PAHs may prevent the occurrence of PM2.5-induced vascular diseases.

Combined LDL and VLDL Electronegativity Correlates with Coronary Heart Disease Risk in Asymptomatic Individuals.

The most electronegative constituents of human plasma LDL (i.e., L5) and VLDL (i.e., V5) are highly atherogenic. We determined whether the combined electronegativity of L5 and V5 (i.e., L5 + V5) plays a role in coronary heart disease (CHD). In 33 asymptomatic individuals (ages 32-64), 10-year hard CHD risk correlated with age (r = 0.42, p = 0.01). However, in age-adjusted analyses, 10-year hard CHD risk correlated with L5 + V5 plasma concentration (r = 0.43, p = 0.01) but not age (p = 0.74). L5 + V5 plasma concentration was significantly greater in the group with high CHD risk (39.4 ± 22.0 mg/dL; n = 17) than in the group with low CHD risk (16.9 ± 14.8 mg/dL; n = 16; p = 0.01). In cultured human aortic endothelial cells, L5 + V5 treatment induced significantly more senescence-associated-ß-Gal activity than did equal concentrations of L1 + V1 (n = 4, p < 0.001). To evaluate the in vivo relevance of these findings, we fed ApoE-/- and wild-type mice with a high-fat diet and found that plasma LDL, VLDL, and LDL + VLDL from ApoE-/- mice exhibited significantly greater electrophoretic mobility than did wild-type counterparts (n = 6, p < 0.01). The increased electronegativity of LDL and VLDL in ApoE-/- mice was accompanied by increased aortic lipid accumulation and cellular senescence (n = 6, p < 0.05). Clinical trials are warranted to test the predictive value of L5 + V5 concentration in patients with CHD.

Using a high-resolution mass spectrometry-based metabolomics strategy for comprehensively screening and identifying biomarkers of phthalate exposure: Method development and application.

Di-(2-propylheptyl) phthalate (DPHP) is an alternative plasticizer that can replace other phthalates currently being scrutinized, and its use and production volumes are increasing. This study aimed to develop a high-resolution mass spectrometry (HRMS)-based metabolomics strategy to comprehensively screen urinary biomarkers of DPHP exposure and filter out potentially useful DPHP exposure markers for human exposure assessments. This strategy included three stages: screening of biomarkers, verification of dose-response relationships in laboratory animals, and application in human subjects. The multivariate data analysis method known as orthogonal partial least-squares discriminant analysis (OPLS-DA) was used to screen and find meaningful signals in an MS dataset generated from urine samples collected from DPHP-administered rats. Thirty-six MS signals were verified as exposure marker candidates by assessing dose-response relationships in an animal feeding study. A biotransformation product of DPHP, mono-(2-propyl-7-dihydroxy-heptyl) phthalate, was suggested as a DPHP exposure marker for general human exposure assessments after the human application study and chemical structure identification. Three previously oxidized DPHP biotransformation products might be suitable for human exposure assessments in high-level exposure groups but not in the general population due to their low sensitivity.

Urinary exposure marker discovery for toxicants using ultra-high pressure liquid chromatography coupled with Orbitrap high resolution mass spectrometry and three untargeted metabolomics approaches.

Human biomonitoring is the assessment of actual internal contamination of chemicals by measuring exposure markers, chemicals or their metabolites, in human urine, blood, serum, and other body fluids. However, the metabolism of chemicals within an organism is extremely complex. Therefore, the identification of metabolites is often difficult and laborious. Several untargeted metabolomics methods have been developed to perform objective searching/filtering of accurate-mass-based LC-MS data to facilitate metabolite identification. In this study, three metabolomics data processing approaches were used for chemical exposure marker discovery in urine with an LTQ-Orbitrap high-resolution mass spectrometry (HRMS) dataset; di-isononyl phthalate (DINP) was used as an example. The data processing techniques included the SMAIT, mass defect filtering (MDF), and XCMS Online. Sixteen, 83, and 139 probable DINP metabolite signals were obtained using the SMAIT, MDF, and XCMS procedures, respectively. Fourteen probable metabolite signals mined simultaneously by the three metabolomics approaches were confirmed as DINP metabolites by structural information provided by LC-MS/MS. Among them, 13 probable metabolite signals were validated as exposure-related markers in a rat model. Six (m/z 319.155, 361.127, 373.126, 389.157, 437.112 and 443.130) of the 13 exposure-related DINP metabolite signals have not previously been reported in the literature. Our data indicate that SMAIT provided an efficient method to discover effectively and systematically urinary exposure markers of toxicant. The DINP metabolism information can provide valuable information for further investigations of DINP toxicity, toxicokinetics, exposure assessment, and human health effects.

Plasma L5 levels are elevated in ischemic stroke patients and enhance platelet aggregation.

L5, the most electronegative and atherogenic subfraction of low-density lipoprotein (LDL), induces platelet activation. We hypothesized that plasma L5 levels are increased in acute ischemic stroke patients and examined whether lectin-like oxidized LDL receptor-1 (LOX-1), the receptor for L5 on endothelial cells and platelets, plays a critical role in stroke. Because amyloid ß (Aß) stimulates platelet aggregation, we studied whether L5 and Aß function synergistically to induce prothrombotic pathways leading to stroke. Levels of plasma L5, serum Aß, and platelet LOX-1 expression were significantly higher in acute ischemic stroke patients than in controls without metabolic syndrome (P < .01). In mice subjected to focal cerebral ischemia, L5 treatment resulted in larger infarction volumes than did phosphate-buffered saline treatment. Deficiency or neutralizing of LOX-1 reduced infarct volume up to threefold after focal cerebral ischemia in mice, illustrating the importance of LOX-1 in stroke injury. In human platelets, L5 but not L1 (the least electronegative LDL subfraction) induced Aß release via IκB kinase 2 (IKK2). Furthermore, L5+Aß synergistically induced glycoprotein IIb/IIIa receptor activation; phosphorylation of IKK2, IκBα, p65, and c-Jun N-terminal kinase 1; and platelet aggregation. These effects were blocked by inhibiting IKK2, LOX-1, or nuclear factor-κB (NF-κB). Injecting L5+Aß shortened tail-bleeding time by 50% (n = 12; P < .05 vs L1-injected mice), which was prevented by the IKK2 inhibitor. Our findings suggest that, through LOX-1, atherogenic L5 potentiates Aß-mediated platelet activation, platelet aggregation, and hemostasis via IKK2/NF-κB signaling. L5 elevation may be a risk factor for cerebral atherothrombosis, and downregulating LOX-1 and inhibiting IKK2 may be novel antithrombotic strategies.

Increased LDL electronegativity in chronic kidney disease disrupts calcium homeostasis resulting in cardiac dysfunction.

Chronic kidney disease (CKD), an independent risk factor for cardiovascular disease, is associated with abnormal lipoprotein metabolism. We examined whether electronegative low-density lipoprotein (LDL) is mechanistically linked to cardiac dysfunction in patients with early CKD. We compared echocardiographic parameters between patients with stage 2 CKD (n = 88) and normal controls (n = 89) and found that impaired relaxation was more common in CKD patients. Reduction in estimated glomerular filtration rate was an independent predictor of left ventricular relaxation dysfunction. We then examined cardiac function in a rat model of early CKD induced by unilateral nephrectomy (UNx) by analyzing pressure-volume loop data. The time constant of isovolumic pressure decay was longer and the maximal velocity of pressure fall was slower in UNx rats than in controls. When we investigated the mechanisms underlying relaxation dysfunction, we found that LDL from CKD patients and UNx rats was more electronegative than LDL from their respective controls and that LDL from UNx rats induced intracellular calcium overload in H9c2 cardiomyocytes in vitro. Furthermore, chronic administration of electronegative LDL, which signals through lectin-like oxidized LDL receptor-1 (LOX-1), induced relaxation dysfunction in wild-type but not LOX-1(-/-) mice. In in vitro and in vivo experiments, impaired cardiac relaxation was associated with increased calcium transient resulting from nitric oxide (NO)-dependent nitrosylation of SERCA2a due to increases in inducible NO synthase expression and endothelial NO synthase uncoupling. In conclusion, LDL becomes more electronegative in early CKD. This change disrupts SERCA2a-regulated calcium homeostasis, which may be the mechanism underlying cardiorenal syndrome.

Sesamol reduces the atherogenicity of electronegative L5 LDL in vivo and in vitro.

Highly electronegative low-density lipoprotein (LDL) L5 induces endothelial cell (EC) apoptosis, which leads to the development of atherosclerosis. We examined the effects of sesamol (1), a natural organic component of sesame oil, on plasma L5 levels and atherosclerosis development in a rodent model and on the L5-induced apoptosis of ECs. Syrian hamsters, which have an LDL profile similar to that of humans, were fed a normal chow diet (control), a high-fat diet (HFD), or a HFD supplemented with the administration of 50 or 100 mg/kg of 1 via oral gavage (HFD+1) for 16 weeks (n = 8 per group). Hamsters in the HFD+1 groups had reduced plasma L5 levels when compared with the HFD group. Oil Red O staining showed that atherosclerotic lesion size was markedly reduced in the aortic arch of hamsters in the HFD+1 groups when compared with that in the HFD group. In human aortic ECs, 0.3-3 µM 1 blocked L5-induced apoptosis in a dose-dependent manner. Further mechanistic studies showed that 1 inhibited the L5-induced lectin-like oxidized LDL receptor-1 (LOX-1)-dependent phosphorylation of p38 MAPK and activation of caspase-3 and increased phosphorylation of eNOS and Akt. Our findings suggest that sesamol (1) protects against atherosclerosis by reducing L5-induced atherogenicity.

Low-density lipoprotein electronegativity is a novel cardiometabolic risk factor.

BACKGROUND: Low-density lipoprotein (LDL) plays a central role in cardiovascular disease (CVD) development. In LDL chromatographically resolved according to charge, the most electronegative subfraction-L5-is the only subfraction that induces atherogenic responses in cultured vascular cells. Furthermore, increasing evidence has shown that plasma L5 levels are elevated in individuals with high cardiovascular risk. We hypothesized that LDL electronegativity is a novel index for predicting CVD. METHODS: In 30 asymptomatic individuals with metabolic syndrome (MetS) and 27 healthy control subjects, we examined correlations between plasma L5 levels and the number of MetS criteria fulfilled, CVD risk factors, and CVD risk according to the Framingham risk score. RESULTS: L5 levels were significantly higher in MetS subjects than in control subjects (21.9±18.7 mg/dL vs. 11.2±10.7 mg/dL, P:0.01). The Jonckheere trend test revealed that the percent L5 of total LDL (L5%) and L5 concentration increased with the number of MetS criteria (P<0.001). L5% correlated with classic CVD risk factors, including waist circumference, body mass index, waist-to-height ratio, smoking status, blood pressure, and levels of fasting plasma glucose, triglyceride, and high-density lipoprotein. Stepwise regression analysis revealed that fasting plasma glucose level and body mass index contributed to 28% of L5% variance. The L5 concentration was associated with CVD risk and contributed to 11% of 30-year general CVD risk variance when controlling the variance of waist circumference. CONCLUSION: Our findings show that LDL electronegativity was associated with multiple CVD risk factors and CVD risk, suggesting that the LDL electronegativity index may have the potential to be a novel index for predicting CVD. Large-scale clinical trials are warranted to test the reliability of this hypothesis and the clinical importance of the LDL electronegativity index.

Nitric oxide production and blood pressure reduction during haemodialysis.

AIM: A decrease of systolic blood pressure in excess of 20 mmHg during haemodialysis treatment (IDD) is common for haemodialysis patients. Intradialytic hypotension (IDH) is symptomatic IDD by definition. Overproduction of nitric oxide (NO) is a possible cause of IDD. Dialysate nitrate and nitrite amount can be used as an indicator of intradialysis NO production. Our aim was to find the predictor of NO production in IDD patients. METHODS: Partial dialysate samples were collected during the whole haemodialysis session and total dialysate nitrate and nitrite amount was measured to assess the association of intradialysis NO production with blood pressure change. RESULTS: There were 31 IDD patients and 71 patients who did not develop IDD (NIDD) included in the study. Among the IDD patients, 13 were IDH patients with a mean systolic blood pressure lower than that of the other 18 symptomless IDD patients (96.6 ± 3.4 mmHg vs 125.0 ± 3.8 mmHg, P<0.001). The median value of NO production was higher in the IDD than in the NIDD patients (447.7 µg vs 238.8 µg, P<0.001). The NO production correlated linearly with blood pressure reduction (R=0.487, P<0.001). The multivariate analysis showed that NO production was positively associated with predialysis systolic blood pressure. CONCLUSION: Nitric oxide production during haemodialysis was higher in IDD than in NIDD patients. IDH often occurred when systolic blood pressure was reduced to below 100 mmHg. The amount of NO produced during haemodialysis, which may be associated with predialysis systolic blood pressure, can be used to predict intradialysis blood pressure decrease.

Gender disparity in LDL-induced cardiovascular damage and the protective role of estrogens against electronegative LDL.

BACKGROUND: Increased levels of the most electronegative type of LDL, L5, have been observed in the plasma of patients with metabolic syndrome (MetS) and ST-segment elevation myocardial infarction and can induce endothelial dysfunction. Because men have a higher predisposition to developing coronary artery disease than do premenopausal women, we hypothesized that LDL electronegativity is increased in men and promotes endothelial damage. METHODS: L5 levels were compared between middle-aged men and age-matched, premenopausal women with or without MetS. We further studied the effects of gender-influenced LDL electronegativity on aortic cellular senescence and DNA damage in leptin receptor-deficient (db/db) mice by using senescence-associated-ß-galactosidase and γH2AX staining, respectively. We also studied the protective effects of 17ß-estradiol and genistein against electronegative LDL-induced senescence in cultured bovine aortic endothelial cells (BAECs). RESULTS: L5 levels were higher in MetS patients than in healthy subjects (P < 0.001), particularly in men (P = 0.001). LDL isolated from male db/db mice was more electronegative than that from male or female wild-type mice. In addition, LDL from male db/db mice contained abundantly more apolipoprotein CIII and induced more BAEC senescence than did female db/db or wild-type LDL. In the aortas of db/db mice but not wild-type mice, we observed cellular senescence and DNA damage, and the effect was more significant in male than in female db/db mice. Pretreatment with 17ß-estradiol or genistein inhibited BAEC senescence induced by male or female db/db LDL and downregulated the expression of lectin-like oxidized LDL receptor-1 and tumor necrosis factor-alpha protein. CONCLUSION: The gender dichotomy of LDL-induced cardiovascular damage may underlie the increased propensity to coronary artery disease in men.

Highly electronegative LDL from patients with ST-elevation myocardial infarction triggers platelet activation and aggregation.

Platelet activation and aggregation underlie acute thrombosis that leads to ST-elevation myocardial infarction (STEMI). L5-highly electronegative low-density lipoprotein (LDL)-is significantly elevated in patients with STEMI. Thus, we examined the role of L5 in thrombogenesis. Plasma LDL from patients with STEMI (n = 30) was chromatographically resolved into 5 subfractions (L1-L5) with increasing electronegativity. In vitro, L5 enhanced adenosine diphosphate-stimulated platelet aggregation twofold more than did L1 and induced platelet-endothelial cell (EC) adhesion. L5 also increased P-selectin expression and glycoprotein (GP)IIb/IIIa activation and decreased cyclic adenosine monophosphate levels (n = 6, P < .01) in platelets. In vivo, injection of L5 (5 mg/kg) into C57BL/6 mice twice weekly for 6 weeks shortened tail bleeding time by 43% (n = 3; P < .01 vs L1-injected mice) and increased P-selectin expression and GPIIb/IIIa activation in platelets. Pharmacologic blockade experiments revealed that L5 signals through platelet-activating factor receptor and lectin-like oxidized LDL receptor-1 to attenuate Akt activation and trigger granule release and GPIIb/IIIa activation via protein kinase C-α. L5 but not L1 induced tissue factor and P-selectin expression in human aortic ECs (P < .01), thereby triggering platelet activation and aggregation with activated ECs. These findings indicate that elevated plasma levels of L5 may promote thrombosis that leads to STEMI.

Background levels of persistent organic pollutants in humans from Taiwan: perfluorooctane sulfonate and perfluorooctanoic acid.

Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) have recently received attention due to their widespread contamination of the environment. PFOS and PFOA are stable in the environment and resistant to metabolism, hydrolysis, photolysis and biodegradation. PFOS and PFOA have been found in human blood and tissue samples from both occupationally exposed workers and the general worldwide population. This study aimed to determine the background levels of PFOS and PFOA in the Taiwanese population, investigate related factors, and compare exposure in Taiwan to that in other countries. The concentration of PFOS in the 59 serum samples collected from the general population in Taiwan ranged from 3.45 to 25.65ngmL(-1) (median: 8.52), and the concentration of PFOA ranged from 1.55 to 7.69ngmL(-1) (median: 3.22). There was a significant positive correlation (r=0.51; p<0.0001) between PFOS and PFOA concentrations. Males had higher concentrations of PFOA and PFOS than females. PFOS levels in serum increased with age. This study is the first investigation to reveal the PFOS and PFOA levels of serum samples in the general population of Taiwan. The levels of PFOS and PFOA in Taiwanese serum samples were comparable with those from other countries (PFOS: 5.0-35ngmL(-1), PFOA: 1.5-10ngmL(-1)).

Coexposure of dioxin-like polychlorinated biphenyls and polychlorinated dibenzo-p-dioxins and dibenzofurans in free-range hens and implications derived from congener profile analysis.

The consumption of free-range eggs is becoming more popular worldwide. We analyzed the levels of 12 dioxin-like polychlorinated biphenyls (dl-PCBs) and their congener profiles from 6 free-range and 12 caged egg samples. The mean levels of dl-PCBs in the free-range samples were 5.4 times higher than those in caged eggs. All egg samples exhibited at least two characteristic dl-PCB congener patterns, which reflected distinctive contamination sources. Additionally, for the first time, we demonstrated that the dl-PCB levels in the free-range eggs were highly correlated with elevated levels of 17 polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) (r = 0.986; p < 0.001), indicating a coexposure scenario in free-range hens. Cluster analysis of congener patterns implied that this coexposure scenario could be attributed to distinct dl-PCB and PCDD/F sources. This congener profile information provides insights from a different perspective for further identifying potential dl-PCB and PCDD/F sources in the polluted free-range eggs.

Identification of di-isononyl phthalate metabolites for exposure marker discovery using in vitro/in vivo metabolism and signal mining strategy with LC-MS data.

Di-isononyl phthalate esters (DINPs) are endocrine-disrupting chemicals and have replaced di(2-ethylhexyl) phthalate (DEHP) as the major plasticizer for poly(vinyl chloride) (PVC) products in recent years. Exposure marker discovery of DINPs is crucial, because of their high potential for human exposure and toxicity. Here, we propose an alternative approach for tracing signals derived from stable isotope-labeled precursors with varied labeling ratios to efficiently filter probable metabolite signals. The statistical process, which involves a signal mining algorithm with isotope tracing (SMAIT), has effectively filtered 13 probable DINP metabolite signals out of the 8867 peaks in the LC-MS data obtained from incubated stable isotope-labeled precursors with liver enzymes. Seven of the 13 probable metabolite signals were confirmed as DINP structure-related metabolites by preliminary MS/MS analyses. These 7 structure-related metabolite signals were validated as effective DINP exposure markers, using urine samples collected from DINP-administered rats without time-consuming comprehensive structure identification. We propose that the 7 identified possible DINP metabolite signals of m/z 279.1, 293.1, 305.1, 307.1, 321.1, 365.1, and 375.1 are potential markers for DINP exposure and should be investigated further. The integrated approach described here can efficiently, and systematically, filter probable metabolite signals from a complex LC-MS dataset for toxic exposure marker discovery. It is a relatively low-cost/rapid workflow for exposure marker discovery.

An occupational exposure assessment of polychlorinated dibenzo-p-dioxin and dibenzofurans in firefighters.

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) are unintentional byproducts of combustion and industrial processes. Firefighters face the risk of occupational exposure to PCDD/Fs. Congener-specific analyses of 17 PCDD/Fs were performed on 20 serum samples collected from firefighters and fire scene investigators, and four soot samples that had deposited on the surfaces of the fire helmets and were collected after the firefighters had fought fires. The PCDD/F concentrations on the helmets that were contaminated by being worn at the fire scenes were 63-285 times higher than those on a clean helmet. The median serum PCDD/F concentration of the 16 firefighters (12 pg WHO(2005)-TEQ g(-1)lipid) was not different from those of the males from the general Taiwanese population (9.4 pg WHO(2005)-TEQ g(-1) lipid). However, the median PCDD/F level in the four fire scene investigators (15 pg WHO(2005)-TEQ g(-1) lipid) was higher than those in the male from the general Taiwanese population (Mann-Whitney U test, p<0.01). Furthermore, the serum samples from the firefighters and fire scene investigators, and the soot samples from the fire scenes presented similarly distinctive PCDD/F profiles that had elevated proportions for 10 PCDF congeners. Limited data indicated that the fire scene investigators were occupationally exposed to PCDD/Fs at the fire scenes. We suggested that the firefighters were not occupationally exposed to PCDD/Fs at the fire scenes due to appropriate protection. However, the fire scene investigators may have had more occupational exposure to PCDD/Fs due to poor protection, and further research must be performed to confirm this.