三氯乙烯对人原代角质形成细胞的细胞毒作用

目的研究体外培养条件下有机溶剂三氯乙烯(Trichloroethylene,TCE)对正常人表皮角质形成细胞(normal human epidermal keratinocyte,NHEK)的毒性作用。方法用0.25%的胰蛋白酶经冷温两步消化皮肤,分离得到NHEK,进行体外无血清培养;根据中性红吸附试验测定的NR50结果,确定TCE染毒剂量。测定乳酸脱氢酶(LDH)活力,反映其对细胞膜的损害,测定丙二醛(MDA)含量和超氧化物歧化酶(SOD)活力,反映细胞脂质过氧化作用。结果TCE可引起NHEK细胞活力剂量依赖性降低,TCE对NHEK的NR50值为4.525 mmol/L(3.922~5.128 mmol/L);NHEK细胞用0.125,0.250,0.500,1.000,2.000 mmol/L的TCE处理1,2,3,4 h后,LDH的释放显示明显的时间-剂量-反应关系;同样剂量的TCE处理NHEK,4 h后可引起MDA含量呈浓度依赖性增加(最低浓度为0.500 mmol/L),SOD活力呈浓度依赖性抑制(最低浓度为0.250 mmol/L),与空白对照和溶剂对照组相比较,两者差异均有显著性(P<0.05)。结论在体外培养条件下,有机溶剂三氯乙烯可通过脂质过氧化和氧化应激作用对人角质形成细胞产生明显的细胞毒作用。     

三氯乙烯诱导皮肤角质形成细胞凋亡的体外研究

目的 检测三氯乙烯（TCE）对人表皮角质形成细胞（NHEK）的凋亡诱导作用,探讨TCE皮肤毒性的作用靶.方法 采用中性红吸附试验测定TCE对体外无血清培养的NHEK的中性红吸附减少50%的浓度（NR50值）,确定TCE染毒剂量;测定丙二醛（MDA）含量和超氧化物歧化酶（SOD）活力反映细胞脂质过氧化作用和氧化状态;用透射电子显微镜（TEM）和流式细胞仪（FCM）观察细胞凋亡形态学改变和测定细胞DNA含量,计算凋亡发生率及增殖指数（PI）.结果 TCE对NHEK的NR50值为4.53（3.92～5.13）mmol/L;TCE处理NHEK 4 h后,MDA含量的增加和SOD活力的抑制均具有剂量-效应关系（r=0.98,r=0.93,P＜0.01）;TEM观察显示,与对照相比,TCE处理组细胞可见明显凋亡改变;FCM测定显示,DNA含量直方图中G1期前可见明显的凋亡峰,与对照组相比,TCE处理组细胞凋亡率明显增高（空白对照及TCE 0.125、0.500、2.000 mmol/L组分别为18.42%、31.83%、38.63%、44.35%）,而PI则明显降低（空白对照及TCE 0.125、0.500、2.000 mmoL/L组分别为4.99%、3.26%、2.48%、2.07%）.结论 在体外培养条件下,TCE可通过脂质过氧化和氧化应激作用诱导NHEK凋亡,抑制其增殖.     

氢醌对体外培养鼠角质形成细胞毒性作用

目的 研究氢醌(Hydroquinone,HQ)对体外培养正常鼠表皮角质形成细胞的毒性作用.方法 用0,1,2.5,5,10和25μg/ml的氢醌处理鼠角质形成细胞,检测氢醌对角质形成细胞的增殖抑制率、乳酸脱氢酶(LDH)释放率、细胞中活性氧(ROS)水平、丙二醛(MDA)含量,并对超氧化物歧化酶(SOD)和还原性谷胱甘肽过氧化酶(GSH-Px)的活力进行测定.结果 氢醌可引起角质形成细胞活力剂量-时间依赖性降低;角质形成细胞用0,1,2.5,5,10和25 μg/ml氢醌处理4,8,12,24 h后,LDH释放率呈明显的时间-剂量-反应关系;同样剂量的氢醌处理角质形成细胞,12 h后可引起ROS、MDA含量呈浓度依赖性增加(最低浓度为5μg/ml),而SOD及GSH-Px活力呈浓度依赖性抑制(最低浓度为2.5μg/ml),与对照组比较差异均有统计学意义(P＜0.05,P＜0.01).结论 在体外培养条件下,氢醌可通过脂质过氧化和氧化应激对鼠角质形成细胞产生明显的毒性作用.     

GbE对TCE诱导人KC细胞氧化损伤的影响

目的探讨三氯乙烯(Trichloroethylene,TCE)对人角质形成细胞(Keratinocyte,KC)氧化损伤的影响及银杏叶提取物(ExtractsfromtheLeavesofGinkgobiloba,GbE)对其拮抗作用。方法采用体外KC无血清培养方法,用中性红吸收实验(NetrualRedUptake,NRU)测定TCE对KC细胞毒性的半数抑制浓度NR50;用乳酸脱氢酶(LDH)法检测KC的损伤;用硫代巴比妥酸法测定KC细胞脂质过氧化物丙二醛(MDA)活力;同时检测细胞内抗氧化酶超氧化物歧化酶(SOD)的活力。结果TCE对KC的NR50为4.53mmol/L;KC在TCE(0.125,0.25,0.5,1.0,2.0mmol/L)作用1,2,3,4h后,LDH释放增加,且具有时间和剂量依赖性,KC在TCE作用4h后,MDA的生成量显著减少,且呈浓度依赖性,与溶剂对照组相比,P<0.05;GbE(10,50,100,150,200mol/L)可以浓度依赖性的减少LDH释放、MDA的生成量,增加SOD的生成量。结论GbE可拮抗TCE引起的人KC损伤。     

三氯乙烯和四氯乙烯对体外培养人皮肤角质形成细胞脂质过氧化的影响

目的探讨有机溶剂三氯乙烯(trichloroethylene,TCE)、四氯乙烯(perchloroethylene,PCE)对体外培养的皮肤角质形成细胞(keratinocyte,KC)的脂质过氧化的作用。方法利用中性红吸附(neutral red uptake,NRU)实验确定TCE和PCE对人KC的中性红半数吸收浓度(50%neutral red uptake,NR50),并根据此确定染毒浓度。分别使用2.0、1.0、0.5、0.25、0.125 mmol/L的TCE或0.8、0.4、0.2、0.1、0.05 mmol/L的PCE对体外培养的人KC染毒4 h,利用MDA、SOD和ROS试剂盒测定细胞中MDA、SOD和ROS水平。结果TCE、PCE对人KC的NR50分别为4.53 mmol/L和2.16 mmol/L。经不同浓度TCE、PCE作用4 h后,细胞内MDA水平和ROS水平随TCE或PCE浓度增加呈上升趋势,而SOD活性呈下降趋势,与溶剂对照组相比较差异有显著性,且存在浓度-反应关系。结论TCE、PCE对人KC有氧化损伤作用。     

维生素E对染镍肺泡巨噬细胞膜脂质过氧化的影响

[目的 ]探讨维生素E拮抗镍所致细胞毒作用及作用机制。 [方法 ]采用体外细胞培养方法 ,观察维生素E对染镍肺泡巨噬细胞膜脂质过氧化产物丙二醛 (MDA)及超氧化物歧化酶 (SOD)活性的影响。 [结果 ]在体外染镍肺泡巨噬细胞培养过程中加入不同浓度的维生素E(2 5、5 0或 10 0 μmol/L)可提高肺泡巨噬细胞内SOD活性 ,具有剂量反应关系。维生素E能显著抑制MDA生成量 ,其中以 5 0和 10 0 μmol/L浓度组作用最为明显。[结论 ]镍可增加细胞脂质过氧化 ,维生素E具有拮抗镍所致细胞毒性的作用 ,可能与其抗氧化功能有关     

三种氯代烯烃对人角质形成细胞的细胞毒性作用

目的　探讨三氯乙烯(trichloroethylene ,TCE )、四氯乙烯(perchloroethylene ,PCE )和二氯乙烯(dichloroethylene ,DCE)对人角质形成细胞(keratinocyte ,KC)的细胞毒性作用以及其时间 剂量 效应关系。方法　利用中性红吸收(neutralreduptake ,NRU)试验测定TCE、PCE和DCE对人KC的中性红半数吸收浓度(5 0 %neutralreduptake ,NR50 ) ,用乳酸脱氢酶(lactatedehydrogenase ,LDH)释放试验研究三者对人KC细胞毒作用,并探讨其时间 剂量 效应关系。结果　TCE、PCE和DCE对人KC的NR50 分别4 .5 3mmol/L、2 . 16mmol/L和5 . 5 7mmol/L ,LDH释放试验表明三者对人角质形成细胞具有明显的细胞毒作用,且具有时间 剂量 效应关系。结论　TCE、PCE和DCE都对人KC具有细胞毒性,且PCE >TCE >DCE。这可能与三者对人KC的细胞膜损伤有关。     

锰化合物对神经母细胞瘤细胞SH-SY5Y脂质过氧化的作用

[目的 ]通过锰染毒神经母细胞瘤细胞 (SH SY5Y) ,观察脂质过氧化及其相关酶水平的改变 ,探讨锰对SH SY5Y的脂质过氧化及相关酶活性的影响 ,为进一步研究锰神经毒作用的机制提供科学依据。 [方法 ]采用浓度为 0 .2 5、0 .5 0、0 .75mmol/L的二价锰和三价锰 ,分别对体外培养的SH -SY5Y细胞染毒 2 4h ,测定超氧化物歧化酶 (SOD)、丙二醛(MDA)、谷胱甘肽 (GSH)、谷胱甘肽过氧化物酶 (GSH Px)和过氧化氢酶 (CAT)的活性。 [结果 ]二价锰和三价锰均可引起SOD、MDA、GSH、GSH Px和CAT活性的改变 ,其中SOD、GSH、GSH Px和CAT活性与对照组比较差异均有显著性 (P <0 .0 5或P <0 .0 1) ,且存在剂量 效应关系。而MDA含量则较对照组升高 (P <0 .0 1) ,且随染毒浓度增高而上升。 [结论 ]一定浓度的锰化合物可使SH SY5Y细胞脂质过氧化反应增强 ,引起相关酶活性的改变。提示这种变化很可能是锰对神经细胞发挥毒作用的重要途径之一。     

p,p'-DDE和β-BHC联合染毒对大鼠离体支持细胞脂质过氧化的影响

目的 研究p,p‘-DDE和β-BHC联合染毒对大鼠离体支持细胞脂质过氧化的影响.方法 通过离体培养SD大鼠支持细胞的四甲基偶氮唑盐(MTT)实验,确定后续实验的染毒剂量,p,p‘-DDE和β-BHC的染毒浓度均为10、30、50μmol/L,p,p‘-DDE β-BHC联合染毒浓度为10μmol/L p,p‘-DDE 10μmol/L β-BHC,30μmol/L p,p‘-DDE 30μmol/L β-BHC,50μmol/Lp,p‘-DDE 50μmol/L β-BHC,检测染毒后支持细胞乳酸脱氢酶(LDH)的漏出率、总超氧化物歧化酶(SOD)活力和丙二醛(MDA)含量的变化.结果 50μmol/L的p,p‘-DDE、β-BHC均可使支持细胞的吸光度(A)值显著下降(P＜0.05).睾丸支持细胞LDH的漏出率随染毒浓度的增加而明显增加(P＜0.05),二者以不同浓度联合染毒时支持细胞LDH的漏出率均显著高于对应浓度的单独染毒(P＜0.05).不同浓度的p,p‘DDE、β-BHC及二者联合染毒均可使细胞内总SOD活力显著降低(P＜0.05)、MDA的含量增加(P＜0.05),且联合染毒时MDA的含量与二者单独染毒时相比均有显著增加(P＜0.05).结论 p,p‘-DDE、β-BHC单独和联合作用均可以引发睾丸支持细胞脂质过氧化,p,p‘-DDE和β-BHC对支持细胞的联合毒性作用具有一定的协同效应.     

二氯乙酸对淋巴细胞的毒性和CXCR2/3表达的作用

目的 探讨三氯乙烯及其代谢产物对淋巴细胞增殖的影响以及二氯乙酸在三氯乙烯药疹样皮炎发病过程中的作用.方法 抽取健康人外周静脉血,分离淋巴细胞,分别在2 h和4 h检测0.02 0.05、0.10、0.20、0.50、1.00、2.00、5.00、10.00、20.00、30.00mmol/L共12个浓度二氯乙酸、三氯乙烯、三氯乙酸刺激培养的淋巴细胞增殖能力;通过中性红试验找到二氯乙酸的半数致死量(NR_(50)),依据NR_(50)检测细胞在不同浓度二氯乙酸刺激下乳酸脱氢酶(LDH)和超氧化物歧化酶(SOD)活力;采用实时荧光定量技术检测二氯乙酸刺激下体外培养的淋巴细胞CXCR2和CXCR3基因mRNA的表达情况.结果 细胞增殖能力检测结果显示,20.00mmol/L二氯乙酸刺激时的细胞活力为50%,而30.00mmol/L三氯乙烯和三氯乙酸刺激的细胞活力仍保持在60%以上.与对照组相比,染毒4 h时各剂量二氯乙酸刺激时SOD活力均明显降低,并且酶活力随剂量的升高呈下降趋势,差异均有统计学意义(P<0.05).第4 h在0.88、1.75、3.50、7.00mmol/L二氯乙酸刺激时的LDH活力与第1 h比较,差异均有统计学意义(P<0.05).在0.5、10.0 mmol/L二氯乙酸刺激培养48 h下,CXCR 2和CXCR3基因mRNA的表达分别是对照细胞表达量的10.34、5.66倍和19.43、8.75倍,差异均有统计学意义(P<0.01).结论 二氯乙酸对体外培养的淋巴细胞具有较强的毒性作用,可能是三氯乙烯药疹样皮炎的主要诱导剂.     

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.     

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.     

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.