Analysis of Blood Concentrations of Zinc, Germanium, and Lead and Relevant Environmental Factors in a Population Sample from Shandong Province, China.

Trace elements, including zinc (Zn) and germanium (Ge), are essential for health; deficiency or excess levels of trace elements results is harmful. As a result of industrial and agricultural production, Pb widely exists in people's living environment. It is absorbed mainly through the respiratory and digestive tracts, producing systemic harm. Reference values for a normal, healthy population are necessary for health assessment, prevention and treatment of related diseases, and evaluation of occupational exposures. Reference ranges for the Chinese population have not been established. From March 2009 to February 2010; we collected data and blood samples (n = 1302) from residents aged 6-60 years living in Shandong Province, China. We measured blood concentrations of Zn, Ge, and Pb using inductively coupled plasma mass spectrometry to determine reference ranges. Results were stratified by factors likely to affect the concentrations of these trace elements: sex, use of cosmetics or hair dye, age, alcohol intake, smoking habits, and consumption of fried food. The overall geometric mean (GM) concentrations (95% confidence interval) were 3.14 (3.08-3.20) mg/L for Zn, 19.9 (19.3-20.6) µg/L for Ge, and 24.1 (23.2-25.1) µg/L for Pb. Blood Zn concentrations were higher in women than in men (p < 0.001), while the opposite was found for Pb (p < 0.001) and sex did not influence Ge (p = 0.095). Alcohol use was associated with higher blood concentrations of Zn (p = 0.002), Ge (p = 0.002), and Pb (p = 0.001). The GM concentration of Zn was highest in 20-30-year-olds (p < 0.001), while Pb concentrations were highest in 12-16-year-olds (p < 0.001). Use of hair dye was associated with lower blood concentrations of Ge (p < 0.05). GM blood concentrations of Pb differed significantly between those who consumed fried foods 1-2 times/month (18.7 µg/L), 1-2 times/week (20.9 µg/L), and every day (28.5 µg/L; p < 0.001). Blood Pb concentrations were higher in subjects who used cosmetics (p < 0.05), hair dye (p < 0.05), and who smoked cigarettes (p < 0.001) than in those who did not.

Inhibition of gap junction intercellular communication is involved in silica nanoparticles-induced H9c2 cardiomyocytes apoptosis via the mitochondrial pathway.

Gap junction intercellular communication (GJIC) between cardiomyocytes is essential for synchronous heart contraction and relies on connexin-containing channels. Connexin 43 (Cx43) is a major component involved in GJIC in heart tissue, and its abnormal expression is closely associated with various cardiac diseases. Silica nanoparticles (SNPs) are known to induce cardiovascular toxicity. However, the mechanisms through which GJIC plays a role in cardiomyocytes apoptosis induced by SNPs remain unknown. The aim of the present study is to determine whether SNPs-decreased GJIC promotes apoptosis in rat cardiomyocytes cell line (H9c2 cells) via the mitochondrial pathway using CCK-8 Kit, scrape-loading dye transfer technique, Annexin V/PI double-staining assays, and Western blot analysis. The results showed that SNPs elicited cytotoxicity in H9c2 cells in a time- and concentration-dependent manner. SNPs also reduced GJIC in H9c2 cells in a concentration-dependent manner through downregulation of Cx43 and upregulation of P-Cx43. Inhibition of gap junctions by gap junction blocker carbenoxolone disodium resulted in decreased survival and increased apoptosis, whereas enhancement of the gap junctions by retinoic acid led to enhanced survival but decreased apoptosis. Furthermore, SNPs-induced apoptosis through the disrupted functional gap junction was correlated with abnormal expressions of the proteins involved in the mitochondrial pathway-related apoptosis such as Bcl-2/Bax, cytochrome C, Caspase-9, and Caspase-3. Taken together, our results provide the first evidence that SNPs-decreased GJIC promotes apoptosis in cardiomyocytes via the mitochondrial pathway. In addition, downregulation of GJIC by SNPs in cardiomyocytes is mediated through downregulation of Cx43 and upregulation of P-Cx43. These results suggest that in rat cardiomyocytes cell line, GJIC plays a protective role in SNPs-induced apoptosis and that GJIC may be one of the targets for SNPs-induced biological effects.

[Influence of genetic polymorphisms of epoxide hydrolase 1 on metabolism of styrene in body].

OBJECTIVE: To investigate the role of genetic polymorphisms of epoxide hydrolase 1 (EPHX1) in the metabolism of styrene in vivo. METHODS: Fifty-six styrene-exposed workers, who worked in the painting workshop of an enterprise for manufacturing glass fiber-reinforced plastic yachts in Shandong Province, China for over one year and were protected in approximately the same way, were selected as study subjects. The 8-hour time-weighted average concentration (8 h-TWA) of styrene and the concentrations of mandelic acid (MA) and phenyl glyoxylic acid (PGA) as urinary metabolites were measured. The genetic polymorphisms of EPHX1 were detected by polymerase chain reaction-restriction fragment length polymorphism analysis. RESULTS: The urinary concentrations of MA and PGA were 177.25±82.36 mg/g Cr and 145.91±69.73 mg/g Cr, respectively, and the 8 h-TWA of styrene was 133.28±95.81 mg/m3. Urinary concentrations of MA and PGA were positively correlated with 8 h-TWA of styrene (R=0.861, P < 0.05; R=0.868, P < 0.05). The subjects were divided into high-exposure group (8 h-TWA >50 mg/m(3)) and low-exposure group (8 h-TWA ≤ 50 mg/m(3), and in the two groups, the urinary concentrations of MA and PGA were significantly higher in the individuals carrying high-activity genotypes of EPHX1 than in those carrying low-activity genotypes of EPHX1 (P < 0.05). CONCLUSION: Genetic polymorphisms of EPHX1 play an important role in the metabolic process of styrene in vivo.

[Meta-analysis of association of tumor necrosis factor alpha and transforming growth factor beta gene polymorphisms with pneumoconiosis].

OBJECTIVE: To evaluate the relationship between tumor necrosis factor-alpha-238, transforming growth factor beta (509 and 869) gene polymorphisms and pneumoconiosis susceptibility. METHODS: We searched published full-text from foreign language databases including Elsevier, PubMed, Wiley Online Library, EMCC, Web of Science, chinese databases containing CNKI, VIP, Wanfang, CBM and Cochrane library to collect case-control or cohort study on gene gene polymorphisms said above with pneumoconiosis susceptibility from the year January1988 to August 2011. 28 relevant articles were selected and 20 of them met the criteria. The correlated index was extracted for aggregate analysis in RevMan 4.2. RESULTS: Among the 20 studies, 10 articles on TNF-α238 polymorphism (including 2232 pneumoconiosis cases and 1985 control subjects), 4 articles on TGF-ß509 polymorphism (including 693 pneumoconiosis cases and 663 control subjects), and 6 articles on TGF-ß869 polymorphism (including 1450 pneumoconiosis cases and 1101 control subjects) were included in the current study. Meta-analysis results showed that there was a significant association between TNF-α238 polymorphism and pneumoconiosis: the population with GA and AA genotypes of TNF-α238 had higher risks to pneumoconiosis (OR = 1.53, 95%CI: 1.25 ∼ 1.88) comparing to GG genotype, and the population with A allele had higher risks to pneumoconiosis comparing to allele G (OR = 1.64, 95%CI: 1.17 ∼ 2.30). The stratified analysis showed that the people with GA and AA genotypes and A allele who were silicosis, Asian or exposed to dust had higher risks to pneumoconiosis (OR = 2.14, 95%CI: 1.20 ∼ 3.82; OR = 2.16, 95%CI: 1.20 ∼ 3.88; OR = 1.78, 95%CI: 1.01 ∼ 3.11; OR = 1.83, 95%CI: 1.04 ∼ 3.22; OR = 1.80, 95%CI: 1.21 ∼ 2.66; OR = 1.50, 95%CI: 1.23 ∼ 1.83). No significant association was found between TGF-ß (509 and 869) gene polymorphisms with pneumoconiosis: In contrast to the CC genotype, the population who had CT and TT genotypes had no higher risks to pneumoconiosis (OR = 1.56, 95%CI: 0.81 ∼ 3.01; OR = 0.96, 95%CI: 0.79 ∼ 1.18); The population who had T allele had no higher risks to pneumoconiosis in contrast to the C allele (OR = 1.35, 95%CI: 0.86 ∼ 2.13; OR = 1.02, 95%CI: 0.91 ∼ 1.15). CONCLUSION: Significant association was found between TNFα238 gene polymorphism and pneumoconiosis; and TGF-ß (509 and 869) were not.

[The increase of micronuclei frequencies of peripheral blood lymphocyte in plywood workers exposed accumulatively to formaldehyde].

OBJECTIVE: To investigate the effects of occupational exposure to formaldehyde on the micronuclei frequencies in peripheral blood lymphocytes of workers. METHODS: Two hundred thirty six plywood workers were divided into 3 exposure groups (low, middle and high) according to internal exposure biomarker (formaldehyde human serum albumin conjugate, FA-HSA), which was detected by ELISA. The concentrations of formaldehyde (FA) in air of two workshops were measure using the high performance liquid chromatography. Cytokinesis-block micronucleus (CBMN) test was used to detect the micronuclei frequencies of peripheral blood lymphocyte in 236 workers. RESULTS: The average concentrations of FA in the low and high exposure workshops were 0.58 +/- 0.20 and 1.48 +/- 0.61 mg/m3, respectively, there was significant difference (P < 0.01). The average concentrations of serum FA-HAS of workers in two workshops were 69.22 +/- 15.37 and 136.29 +/- 89.49 pg/ml, respectively, there was significant difference (P < 0.01). The results of CBMN test showed that the micronucleus frequencies in low, middle and high exposure groups were 1.94 +/- 1.72, 2.10 +/- 1.92 and 2.10 +/- 1.70 per thousand, respectively, there were no significant differences between groups. However, the micronucleus frequencies in accumulative low, middle and high exposure groups were 1.36 +/- 1.36, 2.31 +/- 1.81 and 2.49 +/- 1.92 per thousand, respectively, there were significant differences between different accumulative exposure groups (P < 0.01). The results of correlation analysis indicated that there was a positive correlation between accumulative exposure levels and micronucleus frequencies (r(s) = 0.321, P < 0.01). The accumulative exposure doses may be a risk factor for high micronucleus frequencies in workers exposed to FA (P(trend) = 0.002). CONCLUSION: FA-HSA levels can serve as an internal exposure biomarker for assessing the exposure level of workers exposed to FA. Accumulative formaldehyde exposure resulted in an increase of micronuclei frequencies of peripheral blood lymphocyte in plywood workers.