双酚A对人胚肝细胞DNA损伤和修复功能的影响

[目的]研究双酚A(BisphenolA,BPA)对人肝L-02细胞DNA损伤修复功能的影响。[方法]分别以1、10、50、100μmol/LBPA和100μmol/LBPA+30μg/LVitC处理L-02细胞,比较处理和未处理的人胚肝L-02细胞在DNA损伤程度、切除修复鼠缺陷交叉互补蛋白1(ERCC1)、尿嘧啶DNA糖基化酶(UDG)、错配修复hMSH2基因(hMSH2)、DNA依赖蛋白激酶复合物(DNA-PKcs)及O6-甲基鸟嘌呤甲基转移酶(MGMT)表达水平的差异。每组细胞数均为1×106个/ml。[结果]BPA处理后,彗星试验显示BPA在低剂量(10μmol/L)时即具有DNA损伤作用(P<0.05),随着剂量增大,DNA损伤效应增加。100μmol/LBPA+30μg/LVitC组DNA损伤效应降低,显示抗氧化剂VitC可减缓BPA所致的DNA损伤效应,氧化损伤是BPA所致DNA损伤的方式之一。5种DNA损伤修复酶表达水平在1μmol/L、10μmol/L、50μmol/L剂量组依次降低,在100μmol/L、100μmol/L+VitC组依次增加,50μmol/L组各种DNA损伤修复酶表达水平最低。BPA50μmol/L组与溶剂对照比较,5种DNA损伤修复酶均有明显降低,差异具有显著性(P<0.05)。100μmol/L组的表达水平均高于50μmol/L组,100μmol/L+VitC组均高于100μmol/L组。除DNA-PKcs与hMSH2外,其他DNA损伤修复酶在100μmol/L+VitC组与溶剂对照组比较差异均无显著性(P>0.05)。[结论]BPA对L-02细胞具有氧化损伤作用,并可导致DNA损伤,多种DNA损伤修复酶参与修复双酚A所导致的DNA损伤。VitC可减缓双酚A的DNA损伤作用。     

双酚A及纳米二氧化钛对人胚肝L-02细胞内活性氧含量及DNA损伤的联合作用

[目的]观察双酚A（BPA）、纳米二氧化钛（nano-TiO2）单独及联合作用对人胚肝L-02细胞内活性氧（reactive oxygen species，ROS）含量及DNA损伤的影响。[方法]生长良好的L-02细胞，分别单独加入0．1、1、10μmol／L的BPA，1、5、10mg／L的nano-TiO2，以及上述各浓度的BPA和nano-TiO2混合染毒24h；采用流式细胞仪检测各组L-02细胞内ROS含量，采用彗星试验观察各组DNA断裂损伤程度。[结果]10μmol／L BPA单独染毒组，1mg／L nano-TiO2与1、10μmol／L BPA，以及5、10mg／L的nano-TiO2分别与0．1、1、10μmol／L BPA联合作用于L-02细胞后，均可引起ROS含量升高，DNA断裂损伤加重，与阴性对照组比较差异有统计学意义（P〈0．001）；而nano-TiO2单独染毒组对于L-02细胞ROS的升高、DNA损伤作用与阴性对照组比较差异均无统计学意义（P〉0．05）。析因分析结果显示两种受试物混合染毒存在协同作用。[结论]BPA和nano-TiO2联合作用可增加各自对L-02细胞内ROS水平和DNA损伤断裂水平的影响，对细胞的损伤作用增大。     

铅对原代培养海马神经细胞DNA损伤作用

目的 通过检测细胞生长抑制和凋亡相关的DNA损伤蛋白在大鼠原代培养海马细胞中的表达与原代培养海马细胞DNA损伤的相关性,探讨铅的神经毒理作用机制。方法 原代培养的海马神经细胞,于培养7 d全量更换培养液后加入不同浓度醋酸铅0.2、1.0、10μmol/L,置于37℃、5%CO₂培养箱继续培养24 h;蛋白免疫印迹(west-ern blot)方法检测生长抑制DNA损伤诱导因子(GADD 153)表达;彗星实验检测大鼠海马原代培养神经细胞DNA损伤程度。结果 与对照组比较,随着染铅浓度增高,原代培养的海马神经细胞中的DNA的尾距(OTM)和彗尾值增大,0.2、1.0μmol/L染铅组GADD 153蛋白表达较弱,染铅浓度为10μmol/L时,表达明显增加。结论 细胞DNA损伤与GADD 153蛋白表达呈一定相关性。     

亚砷酸钠对L-02肝细胞的氧化损伤作用

[目的]探讨亚砷酸钠(NaAsO2)对体外培养的人肝细胞株(L-02)的氧化损伤作用. [方法]用不同浓度NaAsO2(50,100,150 μmol/L)染毒L-02肝细胞24 h,MTT法检测NaAsO2对L-02肝细胞生长的影响;流式细胞仪检测L-02肝细胞内活性氧(reactive oxygen species,ROS)水平;钼酸铵法测定过氧化氢酶(catalase,CAT)活性;单细胞凝胶电泳(single-cell gel electrophoresis,SCGE)法检测DNA损伤. [结果]NaAsO2作用L-02肝细胞24h后,50、100、150 μmol/L浓度NaAsO2组的L-02肝细胞存活率和CAT活性与对照组相比显著降低(P<0.01).且呈剂量-反应关系;100、150μmol/L浓度NaAsO2组ROS生成量显著增多(P<0.01);50 μmol/L的NaAsO2即可引起出现彗星现象的细胞数明显高于对照组,拖尾细胞阳性率明显升高(P<0.01),且呈剂量-反应关系. [结论]NaAsO2对L-02肝细胞的生长具有明显的抑制作用,可引起L-02肝细胞内ROS增多和CAT活性降低,引起细胞DNA损伤.     

镉与汞联合作用对人胚肝细胞凋亡和DNA损伤的影响

目的 研究镉与汞单独及联合染毒对人胚肝细胞(L02细胞)凋亡及DNA损伤的作用.方法 以0.01～100μmol/L的氯化镉、氯化汞以及等浓度的氯化镉、氯化汞混合液对L02细胞染毒24 h,采用MTT法测定细胞的存活率,根据Finney法判断镉与汞对L02细胞的联合作用类型;采用单细胞凝胶电泳技术(SCGE)和流式细胞术(FCM)检测L02细胞的DNA损伤和细胞凋亡情况.结果 0.01 μmol/L的氯化镉、氯化汞单独及联合染毒可以刺激细胞的生长,但≥1μmol/L的氯化镉、氯化汞单独及联合染毒可显著抑制细胞的生长;且联合作用表现为相加作用.镉、汞单独及联合作用可致L02细胞的DNA损伤率和细胞凋亡率均显著高于对照组;且随着染毒浓度的升高,L02细胞的DNA损伤率和细胞凋亡率均呈上升趋势.结论 镉汞联合染毒引起的DNA损伤和细胞凋亡可能存在一定的协同效应,这可能是由于镉、汞诱导细胞发生氧化应激所致.     

莲房原花青素对乙醇诱导肝细胞损伤的拮抗作用

目的:研究莲房原花青素(LSPC)对乙醇诱导的人胚肝细胞株L-02损伤的拮抗作用。方法:观察5、10、25mg/L的LSPC与200mmol/L乙醇共同作用于肝细胞L-0224h后,对细胞的生存率,超氧化物歧化酶(SOD)、谷胱甘肽(GSH)、过氧化氢酶(CAT)、丙二醛(MDA)含量、凋亡率以及DNA损伤等指标的影响。结果:与乙醇组相比,5mg/L和10mg/LLSPC使细胞的生存率由73.14%上升到84.79%和90.52%,提高了细胞SOD、CAT、GSH的含量(P<0.01),降低MDA的生成;有效降低细胞的凋亡率,降低细胞p53和生长抑制DNA损伤基因(GADD)34、45β、153的表达,但高剂量组(25mg/L)对乙醇的拮抗作用不明显。结论:适量浓度的莲房原花青素对乙醇诱导的肝细胞L-02的损伤有拮抗作用。     

氢醌对L-02肝细胞DNA损伤及细胞周期的影响

目的 探讨氢醌(HQ)对体外培养L-02肝细胞DNA损伤及细胞周期的影响.方法 将L-02肝细胞用不同浓度(0、5、10、20、40、80、160和320 μmol/L)的HQ作用24 h,采用噻唑蓝(MTT)比色法测定L-02肝细胞的相对存活率,采用单细胞凝胶电泳(SCGE)检测细胞DNA的损伤状况,并采用流式细胞术检测细胞周期分布状况.结果 在0～80 μmol/L的范围内,HQ对L-02肝细胞的存活率没有明显的影响(P＞0.05);当染毒剂量超过160μmol/L时,其存活率则明显地下降(P＜0.01).随着HQ作用浓度的升高,L-02肝细胞DNA链的断裂程度也随着逐渐增加.0～80μmol/L范围内的HQ作用24h后,L-02肝细胞的细胞周期也发生了明显的改变,表现为S期细胞比例明显增加,G1期细胞的比例下降.结论 HQ对L-02肝细胞DNA具有损伤作用,并且在体外能够引起明显的S期细胞阻滞.     

滴滴涕与纳米二氧化钛对人胚肝细胞DNA损伤作用的协同效应

[目的]观察滴滴涕（DDT）及纳米二氧化钛（nano-TiO2）单独及联合体外染毒对人胚肝细胞株（L-02）内活性氧（ROS）含量及DNA损伤的影响。[方法]生长良好的L-02细胞,分别加入0.001、0.01、0.1μmol/L的DDT,0.01、0.1、1μg/mL的nano-TiO2,以及上述各浓度的DDT和nano-TiO2联合剂量,染毒时间均为24 h;运用DCFH-DA作为荧光探针,采用流式细胞检测技术检测DDT与nano-TiO2联合作用下L-02细胞内ROS含量,运用碱性和中性两种彗星试验检测各组DNA断裂损伤程度。[结果]0.01μmol/L以上浓度组DDT单独作用24 h引起ROS升高（P〈0.05）和DNA损伤增加（P〈0.05）;各浓度nano-TiO2单独染毒均不能引起DNA损伤增加（P〉0.05）,但1μg/mL单独染毒可引起ROS升高（P〈0.05）。各剂量组单独染毒24 h后均无明显的DNA双链损伤（P〉0.05）,但可导致DNA单链断裂损伤。析因分析结合反应曲面模型显示两种受试物联合染毒可协同增加ROS水平与DNA损伤作用（P〈0.05）。[结论]DDT和nano-TiO2联合作用可协同增加各自对DNA单链断裂水平的影响,诱导产生ROS导致DNA损伤是DDT和nano-TiO2引起机体损伤的主要机制之一。     

肝肿瘤发生中过氧亚硝酸阴离子标志物作用

目的比较过氧亚硝酸阴离子（ONOO^-）对正常人胚肝细胞株L-02和肝母细胞瘤细胞株HepG2 DNA损伤和细胞毒性差异，探索ONOO^-在肝肿瘤发生中的作用及可能标志物。方法0．01，0．05，0．1mmol／L ONOO^-作用细胞后，检测ONOO^-对2株肝细胞的细胞生存率，超氧化物歧化酶（SOD）、谷胱甘肽（GSH）、过氧化氢酶（CAT）、丙二醛（MDA）含量变化，DNA损伤，生长抑制DNA损伤基因（GADD）表达的影响差异。结果ONOO^-使2种肝细胞的生存率下降、SOD含量降低（P〈0．05）和CAT、GSH的显著变化，显著升高MDA的含量；DNA损伤程度和GADD45、GADD153基因表达水平在2株肝细胞均随着剂量的增加显著升高。2种肝细胞相比，各浓度组L-02细胞损伤程度大于HepG2细胞，但只有GADD基因表达水平差异有统计学意义（P〈0．05）。结论ONOO^-对正常肝细胞和肝癌细胞均显示细胞毒性作用，引起DNA损伤，诱导GADD表达。GADD基因表达水平在不同肝细胞中差异有统计学意义，可能是ONOO^-细胞损伤效应的标志物。     

纳米二氧化钛对氯化镉所致人胚肝L-02细胞毒性作用的影响

[目的]研究纳米二氧化钛(nano-TiO2)对氯化镉(CdCl2)所致人胚肝细胞毒性作用的影响. [方法]不同浓度的CdCl2(0.001、0.01、0.1 μmol/L)单独或与0.01 mg/L nano-TiO2混合后,分别作用干人胚肝L-02细胞24h,观察各组L-02细胞的DNA损伤水平,以及hMsh2基因(hMsh2)、O6-甲基鸟嘌呤甲基转移酶(MGMT)和DNA依赖蛋白激酶复合物催化亚基(DNA-PKcs)的mRNA表达水平. [结果]与相应剂量的CdCl2单独染毒组比较,nano-TiO2与各浓度的CdCl2混合染毒组L-02细胞的DNA损伤加重(P＜0.05),hMsh2表达水平明显上升(P＜0.05),MGMT表达水平无显著性变化,nano-TiO2与0.01、0.μmol/L的CdCl2混合染毒组DNA-PKcs的基因表达水平明显上升(P＜0.05).[结论]0.01mg/L的nano-TiO2可以加重各浓度CdCl2对L-02细胞的DNA单链损伤,从而使CdCl2对L-02细胞毒性作用增强.     

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.     

The occurrence of antimicrobial substances in toilet,sink and shower drainpipes of clinical units: A neglected source of antibiotic residues

Antibiotics represent one of the most important drug groups used in the management of bacterial infections in humans and animals. Due to the increasing problem of antibiotic resistance, assurance of the antibacterial effectiveness of these substances has moved into the focus of public health. The reduction in antibiotic residues in wastewater and the environment may play a decisive role in the development of increasing rates of antibiotic resistance. The present study examines the wastewater of 31 patient rooms of various German clinics for possible residues of antibiotics, as well as the wastewater of five private households as a reference.To the best of our knowledge, this study shows for the first time that in hospitals with high antibiotic consumption rates, residues of these drugs can be regularly detected in toilets, sink siphons and shower drains at concentrations ranging from 0.02?μg·L^?1 to a maximum of 79?mg·L^?1. After complete flushing of the wastewater siphons, antibiotics are no longer detectable, but after temporal stagnation, the concentration of the active substances in the water phases of respective siphons increases again, suggesting that antibiotics persist through the washing process in biofilms. This study demonstrates that clinical wastewater systems offer further possibilities for the optimization of antibiotic resistance surveillance.     

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.