亚砷酸钠对角质形成细胞的氧化损伤作用

目的　探讨亚砷酸钠 (NaAsO2 )对体外培养的人皮肤角质形成细胞株 (HaCaT)的氧化损伤作用。方法　用Alamarblue还原法检测细胞增殖力 ,以Alamarblue还原率表示细胞增殖力 ;用 2′7′-二乙酰二氯荧光素 (DCFH DA)测定细胞内活性氧群 (ROS)水平 ;用彗星实验检测DNA损伤 ;用紫外速率直接法测定细胞内过氧化氢酶 (CAT)的活性。结果　NaAsO2 作用于HaCaT细胞 2 4h后 ,0. 0 0 1～ 1μmol/L组的AlamarBlue还原率显著高于对照组 ,而10 μmol/L以上组AlamarBlue还原率下降 (P <0 . 0 5 ) ;2 5 μmol/L的NaAsO2 即可使二氯荧光素 (DCF)的荧光强度增加 ;5 μmol/L的NaAsO2 可引起单个细胞的彗星尾长显著高于对照组 ;2 5 μmol/L的NaAsO2 即可引起CAT活性明显降低 (P <0 . 0 5 ) ,且呈剂量 -反应关系。结论　低浓度NaAsO2 可刺激细胞增殖而高浓度的NaAsO2 抑制细胞增殖 ,NaAsO2 可引起HaCaT细胞内ROS增多 ,引起细胞DNA损伤和CAT活性降低。     

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.     

氢醌对L-02肝细胞损伤的研究

[目的]探讨氢醌(HQ)对L-02肝细胞损伤及其可能的作用机制。[方法]应用噻唑蓝(MTT)比色法检测浓度分别为0、5、10、20、40、80、160和320gmol/L的HQ作用24h后对L-02肝细胞存活率的影响;利用万能倒置显微镜观察不同浓度HQ染毒之后L-02肝细胞的形态学改变并摄影成像;利用全自动生化分析仪检测不同浓度HQ染毒24h后L-02肝细胞的乳酸脱氢酶(LDH)漏出率和丙氨酸氨基转移酶(ALT)、天门冬氨酸氨基转移酶(AST)活性,以观察HQ对L-02肝细胞膜完整性的影响。[结果]在0～80μmol/L浓度的范围内染毒24h后,HQ对L-02肝细胞的存活率没有明显的影响(P>0.05);浓度≥160μmol/L时,染毒24h后,存活率则明显下降(P<0.01),LDH漏出率、ALT和AST活性均有随着HQ浓度的增加而升高的趋势;160和320μmol/L组LDH漏出率与对照组比较有明显升高(P<0.01)。但ALT和AST活性只在320μmol/L组与对照组比较才有明显增加(P<0.01)。此外,160和320μmol/L组L-02肝细胞的形态与对照组相比发生了明显的改变。[结论]HQ可能是通过损伤细胞膜而对L-02肝细胞产生毒性影响。     

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。     

亚砷酸钠致Chang liver细胞氧化应激作用的研究

目的 研究不同浓度亚砷酸钠(NaAsO2)对人肝细胞株Chang liver的氧化应激作用.方法 采用四甲基偶氮唑(MTF)比色法检测NaAsO2(0、0.1、1、5、10、20、30、50、80、100、200 μmol/L)对Chang liver细胞活力的影响,利用2',7'-二乙酰二氯荧光素(DCFH-DA)检测细胞内活性氧(ROS)水平,利用黄嘌呤氧化法和硫代巴比妥酸比色法测定细胞内超氧化物歧化酶(SOD)活力和丙二醛(MDA)含量.结果 与对照组比较,0.1 μmol/LNaAsO2组细胞活力显著增强(P<05);10～200μmol/L NaAsO2浓度范围内,细胞活力随NaAsO2浓度升高而下降(P<0.05).在0～30 μmol/LNaAsO2浓度范围内,随着NaAsO2浓度的增高,细胞内ROS水平升高(P<0.05),SOD活力降低(P<0.001),MDA含量升高(P<0.001).结论 氧化应激可能是NaAsO2对Chang liver细胞毒性作用的机制之一.     

JNK信号通路在NaAsO2诱导L-02肝细胞 凋亡过程中的作用

摘要:目的　研究JNK在NaAsO2诱导L-02肝细胞凋亡中的作用。方法　用不同浓度NaAsO2染毒L-02肝细胞,采用流式细胞术检测L-02肝细胞凋亡率;Western-blot检测L-02肝细胞中Jnk、p-Jnk、Caspase-3蛋白的相对表达量。结果　0、50、100 和 150 μmol/L组细胞凋亡率分别为3.33%±0.30%、7.49%±0.23%、9.48%±0.49%和 14.87%±2.17%,染毒组的细胞凋亡率随NaAsO2浓度的增加而升高,差异有统计学意义（P＜0.05）;染毒组细胞内Jnk、p-Jnk、Caspase-3蛋白相对表达量均增高,差异有统计学意义（P＜0.05）。结论　NaAsO2能诱导L-02肝细胞凋亡的发生,这可能与激活JNK,增加JNK磷酸化水平,继而激活凋亡调控基因Caspase-3有关。     

砷对人皮肤角质形成细胞抗氧化能力影响

目的 研究亚砷酸钠(NaAsO2)对人皮肤角质形成细胞(HaCaT)抗氧化能力的影响.方法 用流式细胞仪检测细胞内二氯荧光素(DCF)的荧光强度;用改良硫代巴比妥酸荧光法制定细胞内丙二醛(MDA)含量;用Ni-trite-kit法检测超氧化物歧化酶(SOD)活性;用紫外速率直接法测定过氧化氢酶(CAT)的活性.结果 各实验组(2.5,5,10和20 μmol/L NaAsO2)的DCF荧光强度均显著增高(P<0.05),分别是对照组的1.3,1.6,1.7和1.8倍;各实验组MDA含量显著增高(P<0.05),分别是对照组的1.1,1.4,1.5和2.2倍;10和20 μmol/L NaAsO2组SOD活性显著下降,分别为对照组的78%和61%;10和20μmol/L NaAsO2组SIOD和CAT活性显著下降,分别为对照组的50%和34%.结论 砷可以引起人皮肤细胞的氧化损伤,降低抗氧化能力.     

三羟异黄酮对细胞的致突变作用及DNA损伤研究

[目的]主要研究三羟异黄酮(Genistein ,GEN)对细胞的致突变效应及DNA的损伤作用,同时探讨细胞DNA损伤与氧化效应的关系。[方法]采用L5 178Ytk+ / -3 .7.2C小鼠淋巴瘤细胞基因突变试验(MLA)观察GEN在浓度为0、2 .1、4.2、6.3、8.4、10 .5 μmol/L(加S9)时或在浓度为0、12 .5、2 5、5 0、10 0、2 0 0 μmol/L(不加S9)时诱发细胞突变的情况;用单细胞凝胶电泳试验(即彗星试验)检测GEN在浓度为0、10、3 0、90、2 70 μmol/L时对中国仓鼠肺细胞(CHL细胞)和SMMC 772 1肝癌细胞DNA原始损伤,同时测定细胞内超氧化物歧化酶(SOD)和过氧化氢酶(CAT)酶的活性。[结果]GEN在加S9时诱发突变的浓度(≥2 .1μmol/L)显著低于不加S9的浓度(≥2 5 μmol/L)。GEN达到90 μmol/L浓度时作用18h ,可导致CHL细胞和SMMC 772 1肝癌细胞DNA断裂,但CHL细胞各处理组间CAT和SOD差异都无显著性。而SMMC 772 1肝癌细胞在GEN≥3 0 μmol/L时,SOD下降;GEN≥10 μmol/L时,CAT下降。[结论]在加S9时的诱发突变效应剂量远小于不加S9的剂量,表明GEN的代谢产物致突变效应更强。这可能与GEN的代谢产物具有氧化损伤效应有关。但GEN导致细胞DNA断裂,不是由其氧化损伤引起。     

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。     

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.     

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.     

Assessing occupational and environmental exposure

Exposure assessment is a poorly understood component of the science of epidemiology. The relationship between exposure to chemicals and ill-health outcomes is often calculated using crude exposure measures such as ever/never exposed or duration. When investigating subtle effects, exposures need to be characterized much more fully in terms of intensity, frequency, duration and route. While occupational exposures tend to be much greater than those experienced from the wider environment there is a need to remember that, for many chemicals, exposure can occur occupationally, environmentally and through consumer use of products containing the material of interest. Inhalation exposure has generally been the traditional focus for most epidemiological investigations but there is now growing awareness of the importance of the dermal and ingested routes of contact and internalization. Quantification of the exposure also needs to be related to a biological mechanism of action and exposure metrics need to be selected accordingly. Occupational exposures can generally be measured using simple well-validated techniques. Environmental exposures require much more sensitive instruments and are more difficult to assess. Exposure modelling, particularly for the environmental fate of chemicals has undergone many recent developments and Monte Carlo techniques can be used to characterize model uncertainty and variability. This approach to exposure assessment can now be used in the setting of the wider environment and will enable a far better understanding of the relationship between exposure and disease.     

Mercury toxicity due to the smelting of placer gold recovered by mercury amalgam

A 19-year-old man developed tremor in both hands and fatigue after starting work at a placer gold mine where he was exposed to mercury-gold amalgam. Examination revealed an intention tremor, dysdiadochokinesis and mild rigidity. The 24-h urinary mercury concentration reached a peak of 715 nmol/l (143 ug/l) shortly before the clinical examination, after which he was removed from working in the gold room [Mercury No. Adverse Effect Level: 250 nmol/l (50 ug/l)]. On review 7 weeks later his tremor had almost resolved and the dysdiadochokinesis and rigidity had gone. The 24-h urinary mercury concentration had fallen to 160 nmol/l (32 ug/l). The principal exposure to mercury was considered to be the smelting of retorted gold with previously unrecognized residual mercury in it. The peak air concentration of mercury vapour during gold smelting was 0.533 mg/m3 (Mercury Vapour ACGIH TLV: 0.05 mg/m3 TWA). Several engineering and procedural controls were instituted. This episode occurred at another mine site, unrelated to Mount Isa Mines Limited.     

How Adults with Acquired Brain Damage Perceive Computer Training as a Rehabilitation Tool: A Focus-group Study

The aim of this study was to explore and describe how adult outpatients with acquired brain damage and referred to occupational therapy perceive computer training with the RehaCom programs, in order to evaluate the method of treatment as a tool in the rehabilitation of persons with cognitive disorders. By using focus-group discussions as a qualitative method of research when analysing the result, five themes with corresponding categories emerged, describing a development of understanding and learning about capacities. Themes describing how the participants could apply strategies to overcome shortcomings in daily occupations and the therapeutic role of the occupational therapist were identified as well. The result shows that a computer training program such as RehaCom can be used as an educational tool, for example, to guide a person who is trying to adopt compensatory strategies to avoid overload by taking pauses. It was found that anything the participants learned was also applicable to occupational performance in daily life.