280 research outputs found
Paternal Smoking and Risk of Childhood Acute Lymphoblastic Leukemia: Systematic Review and Meta-Analysis
Objective. To investigate the association between paternal smoking and childhood acute lymphoblastic leukemia (ALL). Method. We identified 18 published epidemiologic studies that reported data on both paternal smoking and childhood ALL risk. We performed a meta-analysis and analyzed dose-response relationships on ALL risk for smoking during preconception, during pregnancy, after birth, and ever smoking. Results. The summary odds ratio (OR) of childhood ALL associated with paternal smoking was 1.11 (95% Confidence Interval (CI): 1.05–1.18, I2 = 18%) during any time period, 1.25 (95% CI: 1.08–1.46, I2 = 53%) preconception; 1.24 (95% CI: 1.07–1.43, I2 = 54%) during pregnancy, and 1.24 (95% CI: 0.96–1.60, I2 = 64%) after birth, with a dose-response relationship between childhood ALL and paternal smoking preconception or after birth. Conclusion. The evidence supports a positive association between childhood ALL and paternal ever smoking and at each exposure time period examined. Future epidemiologic studies should assess paternal smoking during well-defined exposure windows and should include biomarkers to assess smoking exposure and toxicological mechanisms
Involvement of N-6 adenine-specific DNA methyltransferase 1 (N6AMT1) in arsenic biomethylation and its role in arsenic-induced toxicity.
BackgroundIn humans, inorganic arsenic (iAs) is metabolized to methylated arsenical species in a multistep process mainly mediated by arsenic (+3 oxidation state) methyltransferase (AS3MT). Among these metabolites is monomethylarsonous acid (MMAIII), the most toxic arsenic species. A recent study in As3mt-knockout mice suggests that unidentified methyltransferases could be involved in alternative iAs methylation pathways. We found that yeast deletion mutants lacking MTQ2 were highly resistant to iAs exposure. The human ortholog of the yeast MTQ2 is N-6 adenine-specific DNA methyltransferase 1 (N6AMT1), encoding a putative methyltransferase.ObjectiveWe investigated the potential role of N6AMT1 in arsenic-induced toxicity.MethodsWe measured and compared the cytotoxicity induced by arsenicals and their metabolic profiles using inductively coupled plasma-mass spectrometry in UROtsa human urothelial cells with enhanced N6AMT1 expression and UROtsa vector control cells treated with different concentrations of either iAsIII or MMAIII.ResultsN6AMT1 was able to convert MMAIII to the less toxic dimethylarsonic acid (DMA) when overexpressed in UROtsa cells. The enhanced expression of N6AMT1 in UROtsa cells decreased cytotoxicity of both iAsIII and MMAIII. Moreover, N6AMT1 is expressed in many human tissues at variable levels, although at levels lower than those of AS3MT, supporting a potential participation in arsenic metabolism in vivo.ConclusionsConsidering that MMAIII is the most toxic arsenical, our data suggest that N6AMT1 has a significant role in determining susceptibility to arsenic toxicity and carcinogenicity because of its specific activity in methylating MMAIII to DMA and other unknown mechanisms
Species diversity patterns of marine plankton and benthos in Chinese bays: Baseline prior to large-scale development
More than 28,000 marine species have been recorded in China, which accounts for approximately 10% of all marine organisms in the world and plays a potentially important role in protecting global marine biodiversity. However, knowledge of marine biodiversity patterns in China is limited, and in particular, no comparative diversity analysis has been carried out for Chinese bays. In this study, national-scale species diversity patterns of coastal bays were examined on the basis of investigations for approximately 81 bays throughout the entire Chinese coastline in the 1980s and the early 1990s, revealing the baseline of diversity patterns prior to large-scale development. Diversity patterns found for coastal bays in China in this study include the following: (1) species richness of benthic macrofauna was larger than that of phytoplankton or zooplankton; (2) spatially, species richness in the subtropical zone was significantly greater than that in the temperate zone; (3) species richness and bay area were significantly correlated and followed power law relationships; and (4) there were significantly positive correlations of species richness among phytoplankton, zooplankton, and benthic macrofauna. The species diversity patterns of marine benthos and plankton for coastal bays in China, in some ways, coincided with general terrestrial patterns. This is the first study to examine national-scale species diversity patterns of coastal bays in China. The findings provide new insights to conservation biology in the marine environment and also are fundamental for future studies of biodiversity and the impact of development on biodiversity
Th ink ing about Undergradua te Course Educa t ion of Un ivers ity Env ironment Spec ia l ity
[摘要]: 论述了从培养目标、课程设置、教学方法与实践等方面培养高素质复合型的环境类专业的本科生, 以满足社
会需求, 并为环境类专业本科教学改革提供参考。[Abstract]:The paper discu sses on t rain ing the h igh quality compound type environm en t speciality
undergraduate f rom som e aspect s of t rain ob ject ive, cu rricu lum , educat ion m ethod and p ract ice in
o rder to sat isfy the dem and of society, and p rovide reference to the undergraduate educat ion refo rm
of un iversity environm en t speciality
Assessing health risks from multiple environmental stressors: Moving from G×E to I×E.
Research on disease causation often attempts to isolate the effects of individual factors, including individual genes or environmental factors. This reductionist approach has generated many discoveries, but misses important interactive and cumulative effects that may help explain the broad range of variability in disease occurrence observed across studies and individuals. A disease rarely results from a single factor, and instead results from a broader combination of factors, characterized here as intrinsic (I) and extrinsic (E) factors. Intrinsic vulnerability or resilience emanates from a variety of both fixed and shifting biological factors including genetic traits, while extrinsic factors comprise all biologically-relevant external stressors encountered across the lifespan. The I×E concept incorporates the multi-factorial and dynamic nature of health and disease and provides a unified, conceptual basis for integrating results from multiple areas of research, including genomics, G×E, developmental origins of health and disease, and the exposome. We describe the utility of the I×E concept to better understand and characterize the cumulative impact of multiple extrinsic and intrinsic factors on individual and population health. New research methods increasingly facilitate the measurement of multifactorial and interactive effects in epidemiological and toxicological studies. Tiered or indicator-based approaches can guide the selection of potentially relevant I and E factors for study and quantification, and exposomics methods may eventually produce results that can be used to generate a response function over the life course. Quantitative data on I×E interactive effects should generate a better understanding of the variability in human response to environmental factors. The proposed I×E concept highlights the role for broader study design in order to identify extrinsic and intrinsic factors amenable to interventions at the individual and population levels in order to enhance resilience, reduce vulnerability and improve health
The Flavoring Agent Dihydrocoumarin Reverses Epigenetic Silencing and Inhibits Sirtuin Deacetylases
Sirtuins are a family of phylogenetically conserved nicotinamide adenine dinucleotide-dependent deacetylases that have a firmly established role in aging. Using a simple Saccharomyces cerevisiae yeast heterochromatic derepression assay, we tested a number of environmental chemicals to address the possibility that humans are exposed to sirtuin inhibitors. Here we show that dihydrocoumarin (DHC), a compound found in Melilotus officinalis (sweet clover) that is commonly added to food and cosmetics, disrupted heterochromatic silencing and inhibited yeast Sir2p as well as human SIRT1 deacetylase activity. DHC exposure in the human TK6 lymphoblastoid cell line also caused concentration-dependent increases in p53 acetylation and cytotoxicity. Flow cytometric analysis to detect annexin V binding to phosphatidylserine demonstrated that DHC increased apoptosis more than 3-fold over controls. Thus, DHC inhibits both yeast Sir2p and human SIRT1 deacetylases and increases p53 acetylation and apoptosis, a phenotype associated with senescence and aging. These findings demonstrate that humans are potentially exposed to epigenetic toxicants that inhibit sirtuin deacetylases
P relim inary resu lts concern ing th e spa tio2tempora l pa ttern and mechan ism of n itrogen sources and expor ts in th e J iu long R iver wa tersh ed
[摘要]:综合运用定位监测、野外试验、模型模拟与G IS技术等手段和方法, 定量研究了南亚热带地区九龙江流域和五川小流域氮的大气沉降、河
流输送(地表径流)、淋失、反硝化和氨挥发等输入输出(源汇)时空模式与机理. 结果表明, 九龙江流域氮/ 源0以化肥与饲料输入为主(占总输
入125. 6kg# hm- 2的86% ), 氮/ 汇0以氨挥发和河流输送为主(占总输出72. 9kg# hm- 2的82% ). 氮输入后50%以上进入大气和水环境, 14. 5%
通过河流输送至河口与近海. 大气氮沉降通量为14. 9kg# hm- 2, 其中干沉降占34%, 湿沉降占66%, 形成1B2 的干湿沉降结构;源于化肥施用与
畜禽养殖引起的强烈氨挥发, 氮沉降集中在春夏两季(占全年80% ), 且以铵态氮为主( 39%以上). 氮的径流输出及河流输送受人为氮输入与
水文条件的双重控制, 2004年九龙江向厦门海域输送无机氮11. 5kg# hm- 2, 其中90%发生在春夏秋季(同期流量占全年89% ); 五川小流域总
氮径流输出负荷为67. 1kg# hm- 2, 其中85%发生在施肥量大、降雨集中的春夏两季(作物生长期); 基流与降雨径流分别贡献25%和75%. 总
氮淋失负荷为27. 5kg# hm- 2, 占总输入的9%; pH < 5的酸性土壤带正电荷导致氮淋失以铵态氮为主(约占40% ). 九龙江流域反硝化通量为
71 7 kg# hm- 2, 而氨挥发高达42. 1kg# hm- 2, 氨挥发主要来自化肥施用与畜禽养殖(分别贡献50% 和39% ). 减少春夏时期肥料氮的输入(养分
管理), 有效截留雨季的降雨径流(水文控制)是该流域氮素管理的关键.国家自然科学基金国际(地区)合作交流项目( No. 40810069004); 福建省/ 十五0重大科技资助项目(N o. 2002H 009
Single molecule quantitation and sequencing of rare translocations using microfluidic nested digital PCR
Cancers are heterogeneous and genetically unstable. New methods are needed that provide the sensitivity and specificity to query single cells at the genetic loci that drive cancer progression, thereby enabling researchers to study the progression of individual tumors. Here, we report the development and application of a bead-based hemi-nested microfluidic droplet digital PCR (dPCR) technology to achieve ‘quantitative’ measurement and single-molecule sequencing of somatically acquired carcinogenic translocations at extremely low levels (<10−6) in healthy subjects. We use this technique in our healthy study population to determine the overall concentration of the t(14;18) translocation, which is strongly associated with follicular lymphoma. The nested dPCR approach improves the detection limit to 1 × 10−7 or lower while maintaining the analysis efficiency and specificity. Further, the bead-based dPCR enabled us to isolate and quantify the relative amounts of the various clonal forms of t(14;18) translocation in these subjects, and the single-molecule sensitivity and resolution of dPCR led to the discovery of new clonal forms of t(14;18) that were otherwise masked by the conventional quantitative PCR measurements. In this manner, we created a quantitative map for this carcinogenic mutation in this healthy population and identified the positions on chromosomes 14 and 18 where the vast majority of these t(14;18) events occur.Trans-National Institutes of Health Genes, Environment and Health Initiative, Biological Response Indicators of Environmental Systems Center Grant [U54 ES016115-01 to M.T.S. and R.A.M.] and National Institute of Environmental Health Sciences Superfund Basic Research Program Grant [P42 ES004705 to M.T.S.]; Canary Foundation and ACS Postdoctoral Fellowship Award in Early Detection [116373-PFTED-08-251-01-SIED to J.S.] from the American Cancer Society; New faculty start-up funds from the University of Kansas (in part to Y.Z.). National Science Foundation Graduate Research Fellowship (to R.N.). Funding for open access charge: National Institutes of Health [U54 ES016115-01]
An improved ion-exchange/diffusion method for N-15 isotope tracing analysis of nitrate in surface waters from watersheds
An improved method, suitable for collecting nitrate from surface waters in the watershed for N-15 isotope tracing analysis, was developed on the basis of the anion exchange coupled with diffusion through systematic simulation and comparison experiments. The results showed that the nitrate could be separated and enriched from the waters efficiently by using the improved method. Being simple and practical in operation principle and procedures, cost-economic, and highly efficient in nitrate separation/enrichment, the method met the requirements of alpha N-15 mass spectrum analysis and would lay a foundation for the application of N-15 isotope tracing approach to the research on non-point source pollution in watershed.Department of Science and Technology of Fujian Province, China [2002H009
Predictive valuation of ecosystem services losses from sea reclamation planning projects in Tong'an Bay
[摘要]:基于围( 填) 海负面生态影响的分析,针对海岸带生态系统各类服务自身的特点,运用直接市场法、替代市场法、调查评价
法和成果参照法,构建了围( 填) 海造成的海岸带生态系统服务损害的货币化评估模型,并应用于厦门同安湾的案例研究。尝
试对同安湾4 个围( 填) 海规划方案可能造成的海岸带生态系统服务损害进行货币化评估。结果显示,从方案一至方案四,随
着围( 填) 海面积的增大,其导致的生态系统服务损失依次为13593 万元/a、54392 万元/a、67937 万元/a 和147848 万元/a,单位
面积损失依次为68. 65 元/( m2·a) 、70. 36 元/( m2·a) 、72. 43 元/( m2·a) 和76. 84 元/( m2·a) 。基于评估结果,针对厦门围( 填) 海
的现状提出了相关的政策建议国家自然科学基金资助项目(70771098
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