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。     

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。     

四氯乙烯对人原代角质形成细胞的细胞毒性作用

[目的]研究体外培养条件下有机溶剂四氯乙烯(perchloroethylene,PERC)对正常人表皮角质形成细胞(normalhumanepidermiskeratinocyte,NHEK)的细胞毒性作用。[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;用中性红吸附试验(NRU)测定PERC对NHEK的中性红吸附减少50%的浓度(NR50值),并据此确定PERC细胞毒性试验的染毒剂量;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]PERC可引起NHEK细胞活力剂量依赖性降低,PERC对NHEK的NR50值为2.16mmol/L(95%可信区间为1.27~3.07);0.05、0.10、0.20、0.40、0.80mmol/LPERC处理NHEK1、2、3、4h后,LDH的释放呈明显剂量-反应和时间-反应关系;以上浓度的PERC处理NHEK4h,可引起MDA含量增加和SOD活力抑制,且均显示剂量-反应关系,与空白对照组、溶剂对照组相比,引起差异有显著性的最低浓度分别为0.20mmol/L(MDA升高)和0.10mmol/L(SOD降低),均为P<0.05。[结论]在体外培养条件下,PERC可能通过氧化应激和脂质过氧化作用对人角质形成细胞产生细胞毒性作用。     

三氯乙烯对人角质形成细胞NO合成及细胞活力的影响

目的 研究三氯乙烯(TCE)对人角质形成细胞(KC)一氧化氮(NO)合成以及细胞活力的影响,探讨三氯乙烯引起皮肤细胞毒性的机制.方法 体外培养的人角质形成细胞以0.125、0.25、0.5、1.0、2.0 mmol/L浓度的TCE染毒4 h,另以诱导型一氧化氮合酶(iNOS)抑制剂氨基胍(AG)100 μmol/L预处理细胞30 min后再行TCE处理,分别于染毒后12 h、24 h、48 h、72 h时检测细胞上清中NO的含量,MTT法观察细胞活力.结果 低剂量的TCE不引起NO含量改变(与溶剂对照比较,P>0.05),0.5、1.0、2.0 mmol/L浓度的TCE染毒组NO含量分别在染毒后的24 h、48 h和72 h开始升高(P<0.05),对应的细胞活力则相应下降(P<0.05);AG预处理的0.5、1.0和2.0 mmol/L TCE染毒组在处理48 h后NO含量开始下降(与对应的TCE染毒组比较,P<0.05),且回复到正常溶剂对照水平(P>0.05),其所对应的细胞活力逐步回升(与对应的TCE染毒组比较,P<0.05).结论 TCE以剂量和时间依赖方式诱导人KC产生NO,而过量的NO可能介导了TCE的KC细胞毒性.     

三氯乙烯对人角质形成细胞一氧化氮和一氧化氮合酶的影响

目的研究三氯乙烯(TCE)对体外培养的人角质形成细胞(KC)一氧化氮(NO)合成和一氧化氮合酶(NOS)表达及活力的影响,探讨TCE的皮肤细胞毒性机制。方法无血清培养的正常人KC与0.125、0.25、0.5、1.0、2.0mmol/L的TCE共培养4h,分别于染毒后12、24、48、72h测定培养液中NO含量和NOS活力,分析其时间—剂量—效应关系,并用逆转录-聚合酶链反应(RT-PCR)法检测诱导型NOS(iNOS)mRNA的表达情况。结果低剂量组(0.125和0.25mmol/L)NO含量与iNOS活力在染毒后各时点与对照组相比均无差异;0.5mmol/L组NO含量与iNOS活力均在染毒后48h开始升高,分别为(32.19±4.75)μmol/L[对照组:(23.70±3.11)μmol/L,P<0.05]和(1.15±0.02)×103U/L[对照组:(0.77±0.06)×103U/L,P<0.05],随着染毒浓度的升高,0.5～2.0mmol/L组NO量与iNOS活力呈上升趋势,而且上升出现的时间提前,1.0和2.0mmol/L组分别于染毒后24和12h出现升高;NO释放的增加总是与iNOS活力升高一致,而结构型NOS(cNOS)活力在各剂量组的各时点均无变化;RT-PCR结果显示TCE可以诱导iNOSmRNA转录水平增高。结论TCE可以诱导人角质形成细胞NO合成增加,大量产生的NO与iNOS基因的上调有关,这一机制可能参与了TCE的皮肤细胞毒性。     

三氯乙烯诱导人角质形成细胞凋亡中Caspase-3活力的研究

目的 观察三氯乙烯(TCE)诱导离体培养的人角质形成细胞(KC)Caspase-3活力变化及细胞凋亡情况,探讨TCE诱导KC凋亡的可能信号通路.方法 以不同浓度(0.125、0.250、0.500、1.000、2.000 mmol/L)TCE对离体分离培养的KC分别染毒至4、8、12、24 h;Caspase-3抑制剂(Z-DEVD-FMK)预处理组,先用100 μmol/L Z-DEVD-FMK预处理细胞1 h,然后再用2.000 mmol/L TCE染毒12 h.用分光光度法检测细胞Caspase-3活力变化,借助Annexin-V/PI双染和流式细胞仪检测细胞凋亡情况.结果 与空白对照相比,TCE染毒4 h,各TCE剂量组Caspase-3活力无明显变化(P>0.05);染毒8 h,1.000 mmol/LTCE组Caspase-3活力和2.000 mmol/LTCE组Caspase-3活力,与对照组相比差异有显著性(P<0.05);TCE染毒12 h和24 h,各TCE剂量组Caspase-3活力明显升高,与对照组相比差异有显著性(P<0.05),且呈剂量-效应关系.各TCE剂量组,在TCE浓度达到0.250 mmol/L以后,细胞凋亡率与对照组相比差异有显著性(P<0.05),且明显呈剂量-效应关系.Z-DEVD-FMK预处理组,与2.000 mmol/L TCE组比较,Caspase-3活力和细胞凋亡率明显得到抑制(P<0.01),而与空白对照相比差异无显著性(P>0.01).结论 在TCE诱导离体培养的KC凋亡中,Caspase-3的活化可能发挥了重要的作用.     

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.     

三氯乙烯和四氯乙烯对体外培养皮肤KC细胞氧化损伤及维生素E的保护作用

目的探讨三氯乙烯（TCE）、四氯乙烯（PCE）对体外培养人皮肤角质形成细胞（KC）氧化损伤作用及维生素E的保护作用。方法将来源于3个或3个以上不同健康个体的皮肤KC细胞混合培养于K—SFM培养基中，利用中性红吸附实验确定其半数抑制浓度（IC50），并据此确定TCE、PCE染毒浓度。染毒4h后，测定细胞内丙二醛（MDA）、超氧化物歧化酶（SOD）、活性氧（ROS）水平；维生素E保护组使用不同浓度维生素E预作用2h后，再分别换入0．5mmol／LTCE或0．2mmol／LPCE与不同浓度维生素E混合物作用4h后，测定细胞内MDA、SOD、ROS水平。结果TCE、PCE能引起体外培养人皮肤KC细胞氧化损伤，且具有浓度一反应关系。而维生素E对其具有保护作用，能下调其氧化损伤，且具有浓度一反应关系。结论TCE、PcE能引起体外培养人皮肤KC细胞氧化损伤，而维生素E对其具有保护作用。     

三氯乙烯诱导人角质形成细胞凋亡过程中caspase-8及caspase-9活力的变化

目的 观察三氯乙烯(TCE)致人原代角质形成细胞(KC)损伤过程中caspase-8、caspase-9活力及细胞凋亡率的变化,探讨TCE引起KC凋亡的可能机制.方法 体外培养的KC分别给予0.125、0.250、0.500、1.000和2.000mmol/L的TCE染毒4、8、12、24 h,以100μmol/L的caspase-9特异抑制剂Z-LEHD-FMK预处理细胞1 h,再用2.000mmol/LTCE染毒12 h.MTT法检测细胞活力变化,分光光度法检测caspase-8及caspase-9活力变化.流式细胞仪检测细胞凋亡率变化.结果 与空白对照相比,2.000和1.000 mmol/LTCE染毒组作用8 h后细胞活力降低.染毒超过12 h,各剂量组细胞活力均降低,差异有统计学意义(P<0.05或P<0.01).在不同的时间段,各剂量组的caspase-8活力与对照组比较,差异无统计学意义(P>0.05).染毒8 h时,2.000mmol/LTCE组caspase-9活力明显高于对照组,差异有统计学意义(P<0.05);12和24h时,各剂量组caspase-9活力与对照组比较,差异均有统计学意义(P<0.05或P<0.01).不同剂量的TCE染毒12 h后,2.000 mmol/L TCE染毒组细胞凋亡率升高至(80.43±4.21)%,空白对照组为(9.40±2.98)%,除0.125 mmol/LTCE组外,其他各染毒组的细胞凋亡率与对照组相比,差异均有统计学意义(P<0.05),剂量-效应关系明显.Caspase-9抑制剂预处理组caspase-9活力及细胞凋亡率较2.000mmol/L TCE染毒组明显降低,差异有统计学意义(P<0.01).结论 Caspase-9的活化在TCE诱导的体外培养的人KC的凋亡过程中发挥重要作用.     

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.     

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.