[Determination of trichloroaldehyde in drinking water using liquid-liquid extraction and gas chromatography].

OBJECTIVE: To establish a liquid-liquid extraction and gas chromatography method for the determination of trichloroacetaldehyde in drinking water. METHODS: Chromatography parameters and extraction parameters, such as extraction solvent, salting out reagents, internal standards and pH were tested and selected. Using the optimized parameters, methods validation and comparison with the national standard examination method was also conducted. RESULTS: Employing the optimized extraction and instrumental analytic parameters, good correlation coefficient was obtained in the linear range of 0.20-20.0 µg/L, with r greater than 0.999. The methods detection limit was 0.030 µg/L. When spiked concentration was 1.0 µg/L for pure water and tap water, the recoveries were 94.8% and 93.7%, respectively, and relative standard deviation was 2.9% and 3.4%, respectively. When spiked concentration was 16.0 µg/L for pure water and tap water, the recoveries were both 101% and relative standard deviation was 1.0% and 1.3%, respectively. Paired samples t test showed that the result obtained with this method were generally lower than that acquired from the national standard examination method. CONCLUSION: This method is sensitive and accurate, and it is suitable for the determination of trichloroaldehyde in drinking water.

Human urinary/seminal phthalates or their metabolite levels and semen quality: A meta-analysis.

Health concerns surrounding human exposure to phthalates include diminished semen quality. Epidemiological findings remain inconsistent. We have performed a quality appraisal and meta-analysis to quantitatively summarize evidence for associations between phthalate exposures and human semen quality. Pubmed and Web of Science were searched for pertinent studies through October 2014. Cited references were reviewed to identify secondary studies. Studies that reported quantitative estimates of the association between phthalates or their metabolite levels in humans and semen quality were eligible. Random effects models were used to calculate pooled effects estimates. Overall, 20 studies met our inclusion criteria. Subsequently, 14 studies were included in the meta-analysis. Urinary monobutyl phthalate (MBP) and monobenzyl phthalate (MBzP) were associated with reduced sperm concentration (MBP [7.4-25.3 µg/L], pooled odds ratio [OR]=2.60, 95% confidence interval [CI]=1.32-5.15; MBzP [14.0-540.2 µg/L], pooled OR=2.23, 95% CI=1.16-4.30). Both MBP (24.6-14,459.0 µg/L) and MEHP (3.1-208.1 µg/L) were inversely associated with straight line velocity (VSL; MBP, pooled ß=-2.51, 95% CI=-4.44, -0.59; MEHP, pooled ß=-1.06, 95% CI=-1.99, -0.12). An IQR increase in MBzP and MEP levels (MBzP, IQR=11.35 µg/L; MEP, IQR=449.4 µg/L) was associated with an increase in comet extent (CE; MBzP, pooled ß=3.57, 95% CI=0.89-6.25; MEP, pooled ß=4.22, 95% CI=1.66-6.77). No associations were observed between monomethyl phthalate and any semen parameters. Our meta-analysis strengthens the evidence that specific phthalates or their metabolite levels may affect semen quality.

Seasonal variability, predictive modeling and health risks of N-nitrosamines in drinking water of Shanghai.

The prevalence of carcinogenic N-nitrosamines in drinking water is of significant concern. In the present study, eight N-nitrosamines from three representative drinking water treatment plants (DWTPs) in Shanghai, China were monitored for an entire year to evaluate their seasonal variability, probabilistic cancer risk and the resulting disease burden. The possibility of employing routinely monitored water quality parameters as predictors of N-nitrosamines was also examined. The results showed that the Taipu River-fed reservoir suffered more serious N-nitrosamine contamination than the Yangtze River-fed reservoirs. Winter witnessed higher levels of N-nitrosamines in both source and finished water. N-nitrosamine concentrations increased from source water to finished water in autumn or winter, but no spatial variations were observed in summer. The total lifetime cancer risk (LCR) posed by N-nitrosamines in finished water was within the acceptable range (1.00 × 10-6 to 1.00 × 10-4), with N-nitrosodimethylamine (NDMA) and N-nitrosodiethylamine (NDEA) being the main contributors. Winter and autumn were found to have higher total LCR values. The average individual disability-adjusted life years (DALYs) lost was 4.43 × 10-6 per person-year (ppy), exceeding the reference risk level (1.00 × 10-6 ppy). Liver cancer accounted for 97.1 % of the total disease burden, while bladder and esophagus cancers made a little contribution (2.9 %). A multiple regression model was developed to estimate the total N-nitrosamines in finished water as a function of water quality parameters, and the R2 value was 0.735. This study not only provides fundamental data for public health policy development, but also reveals the necessity to incorporate a seasonal control strategy in DWTPs to minimize the associated health risks induced by N-nitrosamines.

[SMAD4 gene polymorphisms and genetic susceptibility of coal work's pneumoconiosis].

OBJECTIVE: to explore whether 6 tagging single nucleotide polymorphisms (SNPs) within SMAD4 gene were involved in the genetic susceptibility of coal worker's pneumoconiosis (CWP) by case-control study. METHODS: this study consisted of 438 CWP patients and 448 controls. All study subjects were Han Chinese, underground coal miners and recruited from coal mines of Xuzhou Mining Business Group Co Ltd. The 5 ml venous blood sample was obtained from all studied subjects and extracted genome DNA from the isolated leucocytes. Six SNPs were selected from the HapMap and detected by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). RESULTS: the single SNP analyses showed that the genotype frequencies of SMAD4 (rs10502913) was significantly different from those in controls (P < 0.05). Multivariate logistic regression analyses revealed that SMAD4 (rs10502913) AA genotype was associated with increased risk of CWP (adjusted OR = 1.63, 95%CI = 1.00 - 2.69, P = 0.05) and this was evident among subgroups of those smoker (adjusted OR = 2.28, 95%CI = 1.09 ∼ 4.80, P < 0.05) and cases with stage I (adjusted OR = 2.42, 95%CI = 1.41 ∼ 4.14, P < 0.01). The SMAD4 (rs9304407) GG genotype was associated with an decreased risk of CWP (adjusted OR = 0.65, 95%CI = 0.43 ∼ 0.98, P < 0.05) and the further stratification analysis showed that the risk of CWP was decreased in nonsmoking groups. CONCLUSIONS: our results suggest that individuals with the SMAD4 (rs10502913) AA genotype was associated with an increased risk of CWP. However, carriers of SMAD4 (rs9304407) GG genotype have a protective effect on the developing CWP.

X-ray irradiation selectively kills thymocytes of different stages and impairs the maturation of donor-derived CD4(+)CD8(+) thymocytes in recipient thymus.

The aim of the present study was to determine whether the sensitivity of thymocytes to X-ray radiation depends on their proliferative states and whether radiation impairs the maturation of donor-derived thymocytes in recipient thymus. We assigned 8-week-old C57BL/6J mice into three treatment groups: 1) untreated; 2) X-ray radiation; 3) X-ray radiation plus bone marrow transplantation with donor bone marrow cells from transgenic mice expressing enhanced green fluorescent protein (GFP) on a universal promoter. After 4 weeks, the size of the thymus, the number and proliferation of thymocytes and ratios of different stage thymocytes were analyzed by immunohistochemistry and flow cytometry. The results showed that: 1) CD4(+)CD8(+) thymocytes were more sensitive to X-ray radiation-induced cell death than other thymocytes; 2) the proliferative capacity of CD4(+)CD8(+) thymocytes was higher than that of other thymocytes; 3) the size of the thymus, the number of thymocytes and ratios of thymocytes of different stages in irradiated mice recovered to the normal level of untreated mice by bone marrow transplantation; 4) the ratio of GFP-positive CD4(+)CD8(+) thymocytes increased significantly, whereas the ratio of GFP-positive CD4(+) or CD8(+) thymocytes decreased significantly. These results indicate that the degree of sensitivity of thymocytes to X-ray radiation depends on their proliferative states and radiation impairs the maturation of donor-derived CD4(+)CD8(+) thymocytes in recipient thymus.

Follicle stimulating hormone receptor G-29A, 919A>G, 2039A>G polymorphism and the risk of male infertility: a meta-analysis.

Studies of the relationship between male infertility and polymorphisms in the regions of FSHR G-29A (rs1394205), 919A>G (Thr(307)Ala, rs6165) and 2039A>G (Asn(680)Ser, rs6166) have reported inconsistent results. To assess the association between them, a meta-analysis was conducted. PubMed and CBMdisc literature search were conducted to identify all eligible studies investigating such a relationship. The pooled ORs were performed for co-dominant model, dominant model and recessive model in FSHR G-29A, Thr(307)Ala and Asn(680)Ser respectively to assess the strength of association. A total of 1644 male infertility cases and 1748 controls were collected from seven case-control studies. In the overall analysis, no significant association between the three polymorphisms and risk of male infertility was observed. Stratified analysis showed that there were no significantly increased risks of azoospermia and oligoasthenoteratozoospermia (OAT) in any of the genetic models. This meta-analysis supports that FSHR G-29A, Thr(307)Ala and Asn(680)Ser polymorphisms may not be capable of causing male infertility susceptibility.