农药咪鲜安雌激素样作用机制体外研究

目的用体外试验检测农药咪鲜安的雌激素样作用,并对其可能的作用机制进行探讨。方法将人乳腺癌细胞株（MCF-7）细胞在含10%小牛血清的RPM11640培养基中进行半开放式贴壁培养,加受试物前2周,改在含10%去激素小牛血清的无酚红RPMI 1640培养基中培养。设溶剂对照组、阳性对照组及5个不同浓度的咪鲜安样品组,采用MCF-7细胞增殖试验、四甲基偶氮噻唑蓝（MTT）试验和生长曲线观察咪鲜安对MCF-7细胞增殖的影响,并通过雌激素受体（ER）结合试验分析咪鲜安与ER的结合情况,探讨可能的作用机制。结果咪鲜安在10-7~10-5mol/L剂量范围内可诱导MCF-7细胞增殖,差异有统计学意义（P〈0.05或P〈0.01）,且存在剂量-效应关系;咪鲜安能竞争性地与ER结合,从而抑制125I-E2与ER结合。结论咪鲜安具有雌激素样作用,其作用机制在于其竞争性地与ER的结合。     

邻苯二甲酸二丁酯的拟雌激素活性研究

目的探讨邻苯二甲酸二丁酯(DBP)的拟雌激素活性。方法对雌激素敏感的人乳腺癌MCF-7细胞在RPMI 1640培养基中采用开放式单层贴壁培养,开始实验前将细胞用PBS洗涤后改为在无酚红RPMI 1640培养基中培养5d,实验设溶剂对照、雌激素阳性对照和邻苯二甲酸二丁酯各剂量组(10^-7-10^-3mol／L),采用四唑盐(MTT)法、生长曲线、有丝分裂指数和细胞克隆形成试验对MCF-7细胞增殖情况进行分析。结果与溶剂对照组相比,10^-5mol／LDBP处理24h就可促进MCF-7细胞增殖,提高增殖指数;随着培养时间延长至96h,其他浓度DBP也表现出促进细胞增殖的效果,且浓度在10^-5mol／L时,细胞增殖活性达到最大;在对数生长期,DBP可提高MCF-7细胞的有丝分裂指数;10^-5mol／LDBP处理48h就可增强MCF-7细胞形成细胞克隆的能力。结论邻苯二甲酸二丁酯可促进雌激素依赖性乳腺癌MCF-7细胞的增殖,可能具有拟雌激素作用。     

P,P’-DDD对人乳腺癌细胞的增殖作用

[目的]观察对,对-二氯二苯基二氯乙烷（P,P’-DDD）对人乳腺癌（MCF-7）细胞增殖的影响。[方法]采用体外培养MCF-7细胞增殖试验检测DDD的类雌激素活性,并用生长曲线对其作用机制进行初步探讨。[结果]DDD染毒剂量在3×10^-7mol／L、3×10^-6mol／L时,存在刺激MCF-7细胞增殖的类雌激素活性（P〈0．05）,在3×10^-6mol／L剂量时其增殖效应最大。细胞生长曲线方面,DDD组在第3、5、7天各时间段细胞数均明显高于溶剂对照组（P〈0．05）。[结论]DDD在3×10^-7mol／L、3×10^-6mol／L具有刺激MCF．7细胞增殖的类雌激素活性。     

农药杀螟硫磷环境雌激素活性的研究

[目的]通过大鼠子宫增重试验对农药杀螟硫磷的环境雌激素活性进行研究。[方法]选用21d龄雌性Wistar大鼠,以杀螟硫磷13.33mg/kg.bw、20.00mg/kg.bw和40.00mg/kg.bw为低、中、高剂量组,连续灌胃染毒3d,溶剂对照组使用玉米油,阳性对照组使用雌二醇。第4天处死动物,测定动物子宫重量及血清中雌二醇(E2)、孕酮(P)、促卵泡生成激素(FSH)和促黄体生成激素(LH)水平。[结果]与溶剂对照组相比,杀螟硫磷低、中、高剂量组子宫增大,子宫重量(溶剂对照组、杀螟硫磷低、中、高剂量组分别为29.00、38.57、41.38、48.29mg)和子宫系数(溶剂对照组、杀螟硫磷低、中、高剂量组分别为4.47、5.88、6.76、7.92)增加,血清中E2水平(溶剂对照组、杀螟硫磷低、中、高剂量组分别为21.87、23.68、26.16、27.80pg/ml)和P水平(溶剂对照组、杀螟硫磷低、中、高剂量组分别为2.60、2.95、3.12、3.14ng/ml)升高,且差异有统计学意义。[结论]杀螟硫磷表现出环境雌激素活性,且此作用存在剂量-反应关系。     

用MCF-7细胞检测多氯联苯拟雌激素样活性

目的观察多氯联苯（PCB）对MCF-7细胞增殖及生长曲线的影响。方法选用多氯联苯（1254）进行MCF-7人乳腺癌细胞增殖实验。结果PCB组细胞增殖指数均明显高于溶剂对照组，10ng／LPCB可诱导MCF-7细胞最大增殖（P〈Q01）。生长曲线分析也显示，PCB、E2生长曲线明显上移，有明显刺激MCF-7细胞增殖的类雌激素活性。结论提示PCB具有拟雌激素样活性。     

双酚A对乳腺癌MCF-7细胞的增殖作用及对其癌基因EphA2和c-Myc的mRNA表达水平的影响

[目的]研究具有类雌激素效应的环境污染物双酚A（Bisphenol A，BPA）对雌激素受体（Estrogen Receptor，ER）阳性的乳腺癌MCF-7细胞增殖作用及对其中癌基因EphA2和c-Myc mRNA表达的影响。[方法]以10^-4、10^-5、10^-6、10^-7、10^-8、10^-9、10^-10mol／L等不同浓度的BPA对体外培养的MCF-7细胞进行染毒，通过细胞计数检测细胞增殖情况并使用RT-PCR方法测定细胞EphA2和c-Myc的mRNA表达量。[结果]BPA作用MCF-7细胞后可引起细胞增殖，各浓度组均高于溶剂对照组（P〈0．05）；并使其中的EphA2和c-Myc的mRNA表达呈现上升趋势，各浓度组c-Myc的mRNA水平要高于溶剂对照组（P〈0．05）。[结论]BPA引起的细胞增殖可能是通过EphA2和c-Myc等癌基因的表达增加而引起的，并且BPA对细胞的增殖作用有一定的浓度范围。     

有机磷与拟除虫菊酯农药的拟雌激素活性研究

目的观察有机磷与拟除虫菊酯农药的拟雌激素活性.方法选用5种有机磷农药[辛硫磷(Pho)、马拉硫磷(Mal)、乐果(Dim)、久效磷(Mon)和水胺硫磷(Opt)]和4种拟除虫菊醋农药[氰戊菊酯(Fen)、溴氰菊酯(Del)、氯氰菊酯(Cyp)和苄氯菊酯(Per)],进行大鼠子宫雌激素受体(ER)竞争结合试验和人乳腺癌MCF-7细胞增殖试验.结果 5种有机磷农药在体外均不与大鼠子宫ER结合,不能诱导MCF-7细胞增殖;4种拟除虫菊酯农药在体外能与2,4,6,7-3H雌二醇(3H-E2)竞争ER,其结合能力Fen＞Cyp＞Per＞Del,Fen与Cyp抑制3H-E2与ER结合的IC50分别为0.479、0.562 mmol/L;拟除虫菊酯能引起MCF-7细胞不同程度的增殖,刺激增殖能力Per＞Fen＞Del＞Cyp,其中Cyp、Del和Per所引起的增殖效应能被雌激素拮抗剂ICI 178.820完全阻断,而Fen所引起的细胞增殖不能被完全阻断.结论观察的5种有机磷农药不具有拟雌激素活性;4种拟除虫菊酯农药通过激活ER显示其拟雌激素活性.Fen诱导的MCF-7细胞增殖不完全是由ER激活所引起.     

植物雌激素对乳腺癌细胞MCF-7增殖的影响

目的 :　探讨植物雌激素大豆异黄酮 (genistein,GS)和玉米赤霉烯酮 (zearalenone,ZEA)对乳腺癌细胞株 MCF- 7增殖的影响。方法 :　雌激素依赖性 MCF- 7细胞在 DMEM培养液(含小牛血清 1 0 % )中采用开放式单层贴壁培养 ,于加受试物前 5 d将细胞用 PBS洗涤后改为无酚红高糖 DMEM(含 5 %经活性碳 -葡聚糖苷处理的胎牛血清 ,CDT- FBS)培养 ,实验设溶剂对照、雌激素对照、抗雌激素对照及两种受试物各四个剂量组 ,采用噻唑蓝 (MTT)法、3H- Td R掺入法及流式细胞术对 MCF- 7细胞的增殖情况进行分析。结果 :　与溶剂对照组相比较 ,GS(96μmol/ L,2 4h)可明显抑制 MCF- 7细胞增殖和细胞 DNA合成 ,并将细胞周期阻滞在 G2 / M;8μmol/ L GS处理96 h也能产生类似的抑制效果。 96 nmol/ L ZEA处理 2 4 h可明显促进 MCF- 7细胞增殖和细胞DNA合成 ,并将细胞周期由 G0 / G1向 S期推进 ,提高细胞分裂增殖指数。结论 :　ZEA和 GS均属环境雌激素 ,但对乳腺癌细胞 MCF- 7增殖产生的影响不同 ,ZEA可促进 MCF- 7增殖 ,而 GS能够抑制 MCF- 7细胞的增殖 ,即 GS具有用于癌症预防及有关保健食品开发的价值     

有机磷农药环境雌激素样的作用

目的 初步探索几种常用有机磷农药的环境雌激素样作用,为有机磷农药对食品污染的综合防治提供依据。方法通过MCF-7人乳腺癌细胞增殖试验,对乐果(Dimethoate)、对硫磷(Parathion)、对氧磷(Paraoxon)3种有机磷农药进行雌激素样活性研究。结果 乐果10-5 mol·L-1、10-6mol·L-1剂量组对MCF-7乳腺癌细胞的增殖指数分别为1.31±0.07、1.56±0.08,较对照组的1.00±0.14有显著差异(P<0.05);对硫磷在10-6mol·L-1、10-7mol·L-1剂量组对MCF-7细胞的增殖指数分别为1.35±0.02、1.39±0.09,与对照组相比也有显著差异(P<0.05)。结论 乐果、对硫磷在适宜剂量范围内有拟雌激素样作用。     

染料木黄酮对人乳腺癌细胞雌激素样作用机制研究

目的 探讨染料木黄酮(genistein,GEN)对人乳腺癌细胞增殖影响及作用机制.方法 MTT法测定GEN对雌激素依赖性乳腺癌细胞MCF-7和非雌激素依赖性乳腺癌细胞MDA-MB231增殖作用,应用雌激素受体拮抗剂IC1182780观察GEN的雌激素样作用途径,采用流式细胞术分析乳腺癌细胞周期情况.结果 GEN可促进MCF-7细胞的增殖,使G1期向S期转变,增殖作用可被雌激素受体拮抗剂所拮抗;对非雌激素依赖性MDA-MB231细胞增殖无影响.结论 GEN通过雌激素受体(ER)介导而发挥雌激素样活性作用.     

Calcium intake in the elderly: validation of a dietary questionnaire

Epidemiological studies of calcium and osteoporosis have been hampered by the lack of a suitable tool for assessing calcium intake. This report describes a new frequency and amount questionnaire for measuring present and past calcium intake in the elderly. The validity of the questionnaire was tested against two commonly used standards of dietary assessment, five-day duplicate diets and seven-day weighed dietary inventories. The resulting correlation coefficients were, respectively, r = 0.76 and r = 0.69, while that for repeatability was r = 0.84. Furthermore, the questionnaire categorized subjects into thirds of the distribution of intake with almost no gross misclassification. It is suggested that the present findings may be extended to the majority of normal, healthy elderly subjects, implying wide application for the questionnaire in the assessment of calcium intake in the elderly.     

Self-reported health problems among Swedish miners one year after unemployment

Unemployment is considered to be a public health concern sincedeterioration in the health of the unemployed is often anticipated.However, for some groups, such as miners, unemployment mightimprove health due to a cessation of potentially harmful occupationalexposures. This study evaluates the health of 79 miners in oneSwedish iron-ore mine, and 226 age-matched controls from thegeneral population, during one year after the closure of themine. The participants received a questionnaire regarding medicalhistory and subjective symptoms at the beginning of the studyperiod, and after one year. Statistically significant negativeeffects on self-reported health attributable to unemploymentwere not found, although neuropsychiatric symptoms were morecommon among the unemployed miners. The miners reported a statisticallysignificant improvement in grip force (p=0.031). They had asignificantly higher prevalence of symptoms associated withmining related exposures when compared with the population controls;pain in the upper extremities [relative risk (RR)=2.27, 95%confidence interval (Cl)=1.44–3.59), back pain (RR=1.84;Cl=1.237–2.75), vasospastic disease of the fingers (RR=2.05;Cl=1.18–3.57) and obstructive respiratory symptoms (attacksof dyspnea and wheezing: RR=3.67; Cl=1.167–11.6).     

Excès de cas humains et animaux de tularémie en France au cours de l’hiver 2007–2008 : émergence ou phénomène isolé ?

Context

Tularemia is a zoonosis affecting humans and hares in France. We describe the results of surveillance in both species, in 2007 and 2008.

Methods

Human tularemia cases are mandatorily notifiable in France since 2003. In hares, surveillance relies on volunteer hunter associations in all districts of the country. Data from mandatory reports and volunteer surveillance in 2007/2008 were analyzed and compared with previous results.

Results

In 2007/2008, 144 cases were reported in humans and 117 cases in hares. This was a 100% increase compared to previous years. Human cases differed from those of previous years only by the frequency of contact with breeding animals. Human cases without any documented risk exposure were also more frequent.

Conclusion

An increase of tularemia cases occurred in 2007/2008 in both species. Complementary studies are needed to identify the species reservoir in France to understand the causes of this peak of cases.     

Occupational health hazards in mining: an overview

This review article outlines the physical, chemical, biological, ergonomic and psychosocial occupational health hazards of mining and associated metallurgical processes. Mining remains an important industrial sector in many parts of the world and although substantial progress has been made in the control of occupational health hazards, there remains room for further risk reduction. This applies particularly to traumatic injury hazards, ergonomic hazards and noise. Vigilance is also required to ensure exposures to coal dust and crystalline silica remain effectively controlled.     

Manufacture and use of nanomaterials: current status in the UK and global trends

This paper provides an overview of the production and use of nanomaterials (NMs), particularly in the UK. Currently, relatively few companies in the UK are identifiable as NM manufacturers, the main emphasis being the bulk markets in metals and metal oxides, and some niche markets such as carbon nanotubes and quantum dots. NM manufacturing in the UK does not reflect the global emphasis on fullerenes, nanotubes and fibres. Some assumptions have been made about the types of NM that are likely to be imported into the UK, which currently include fullerenes, modified fullerenes and other carbon-based NMs including nanotubes. Many university departments, spin-offs and private companies have developed processes for the manufacture of NMs but may only be producing small quantities for research and development (R&D) purposes. However, some have the potential to scale up to produce large quantities. The nanotechnology industry in the UK has strong R&D backup from universities and related institutions. This review has covered R&D trends at such institutions, and appropriate information has been added to a searchable database. While several companies are including NMs in their products, only a few (e.g. manufacturers of paints, coatings, cosmetics, catalysts, polymer composites) are using nanoparticles (NPs) in any significant quantities. However, this situation is likely to change rapidly. There is a need to collect more information about exposure to NPs in both manufacturing and user scenarios. As the market grows, and as manufacturers switch from the micro- to the nanoscale, the potential for exposure will increase. More research is required to quantify any risks to workers and consumers.     

深圳公立医院管理体制改革制度设计

深圳公立医院管理体制改革实行政事分开、管办分开,在理事会架构下按法定机构模式组建市医管中心,落实公立医院运营管理自主权.作者从当前公立医院管理体制的弊端入手,介绍了深圳市进行公立医院管理体制改革的基本思路及改革方案设计的主要举措,深入剖析了的改革方案的特点,并对改革效果进行了预测.     

Effects of nitrogen dioxide on red blood cells of rats: Changes in components of red cell membranes during in vivo exposure to NO2

Red cell membranes, prepared from red blood cells of rats exposed to 4, 10, or 20 ppm nitrogen dioxide (NO₂) for 1 to 10 days, were examined for evidence of changes in membrane components. Appreciable changes were not found in contents of phospholipid and cholesterol during exposure to 10 ppm NO₂. By contrast, protein content altered with the time of exposure. Moreover, changes in protein composition were observed by employing sodium dodecyl sulfate — polyacrylamide gel electrophoresis. Twenty-four-hour exposure to NO₂ at the concentration above 10 ppm resulted in a marked increase in the percentage of lysophosphatidylethanolamine (LysoPE) to the total phospholipids. The prolonged exposure to 10 ppm NO₂ gave rise to a further increase in LysoPE, whereas the percentage of phosphatidylethanolamine (PE) showed a gradual decrease. A 1-day exposure to 4.0 ppm NO₂ also caused an increase in sialic acid content and decreases in those of PE and hexose. In addition to contents of these components the percentage of LysoPE increased 5 days after exposure and the elevated values were maintained up to the end of exposure period. These results demonstrate that red blood cells in circulation exhibit different membrane properties in terms of lipid and carbohydrate composition during 10 days of exposure to 4.0 ppm NO₂.     

Investigating clusters in the workplace and beyond

Clusters of disease are common and occur in the workplace and in the general community. They often arouse considerable concern among the population. Investigations have sometimes lead to exciting new knowledge, but in general the investigation of clusters is difficult and often unrewarding, especially for community clusters. In the workplace, investigations are more likely to find associations and even new causes, but still many clusters remain enigmatic. Despite this, there are many reasons for investigating clusters, including allaying community concern and identifying uncontrolled exposures. A structure for investigating clusters in the workplace is suggested.