不同波段电磁辐射对淋巴细胞的损伤效应

目的 探讨电磁脉冲(EMP)、S波段高功率微波(S-HPM)和X波段高功牢微波(X-HPM)3种不同波段的电磁波对Raji细胞的损伤效应.方法 采用流式细胞技术检测3种波段电磁波辐照后6h Raji细胞周期、凋亡率和坏死率;采用共聚焦显微镜检测辐照后6 h Raji细胞Ca2+浓度.结果 各辐射组S期细胞数均明显少于对照组.G0/G1期细胞数均明显多于对照组,差异有统计学意义(P＜0.05);X-HPM组G2/M期细胞数低于对照组,差异亦有统计学意义(P＜0.05).各辐射组细胞凋亡率均高于对照组,其中EMP组和X-HPM组与对照组的差异有统计学意义(P＜0.05,P＜0.01);辐射组间比较,EMP组和X-HPM组细胞凋亡率均明显高于S-HPM组,差异亦有统计学意(P＜0.05,P＜0.01).各辐射组细胞坏死牢均明显高于对照组,差异有统计学意义(P＜0.01);各辐射组间比较,EMP组坏死率明显高于SHPM组和X-HPM组,差异亦有统计学意义(P＜0.01).各辐射组细胞内Ca2+荧光强度均明显高于对照组,差异有统计学意义(P＜0.01);各辐射组间比较,EMP组和X-HPM组ca2+荧光强度均明显高于SHPM组,差异亦有统计学意义(P＜0.01).结论 3种波段电磁波对Raji细胞引起的损伤效应相似,但程度不同,以EMP组最严重,S-HPM组最轻,其机制可能与细胞内Ca2+超载有关.     

牛磺酸对大鼠视网膜谷氨酸兴奋毒性的防护作用研究

目的:探明牛磺酸能否有效防护谷氨酸兴奋毒性引起的大鼠视网膜尤其是视网膜神经节细胞(retinalganglioncells,RGCs)损伤。方法:通过玻璃体注射谷氨酸建立大鼠视网膜谷氨酸兴奋毒性损伤模型,分为正常对照组,谷氨酸组,牛磺酸干预高、低剂量组,MK-801干预组(阳性对照组)和玻璃体注射PBS对照组。观察谷氨酸兴奋毒性对大鼠视网膜组织病理结构、超微结构、视网膜电图、RGCs数量的影响及牛磺酸的防护效应。结果:玻璃体注射谷氨酸使视网膜内层尤其是内网状层厚度变薄;内核层细胞:RGCs的超微结构发生变性改变;视网膜电图的a波、b波下降;神经节细胞层的细胞数显著减少(减少53%),以RGCs的减少为主(减少75%)。腹腔注射高剂量(25mg/kgbw)牛磺酸可有效防护谷氨酸所致上述损伤及RGCs数量的减少,而低剂量(5mg/kgbw)牛磺酸的作用不明显。结论:牛磺酸可有效防护谷氨酸兴奋毒性引起的视网膜尤其是RGCs损伤。     

电磁脉冲对小鼠脾脏淋巴细胞病理变化和凋亡的影响

目的 研究电磁脉冲(electromagnetic pulse,EMP)对小鼠脾脏淋巴细胞病理变化和凋亡的影响.方法 用场强为200 kV/m的EMP,辐照雄性BALB/c小鼠,每天照射400次,连续照射7d,照后1、3、7、14、28d共5个时间点处死小鼠取脾脏,观察其病理改变;处死后称取小鼠的体重和脾脏的重量,计算脾脏指数;然后提取淋巴细胞进行计数;通过流式细胞仪检测淋巴细胞的凋亡和周期;通过transwell实验观察淋巴细胞的趋化能力.结果 照后1d脾脏的组织结构无明显改变;3d后,脾脏血窦扩张,充血明显,脾小体结构不清;脾脏指数呈现波浪状的趋势,在第1、14天,辐照组与对照组无明显差异,在第3、7天,辐照组的脾脏指数高于对照组,第28天辐照组的脾脏指数低于对照组,差异有统计学意义(P＜0.05);淋巴细胞数的变化也呈现先增后减的趋势,在第1、14、28天,辐照组与对照组淋巴细胞数量无明显差异,在第3和7天,辐照组淋巴细胞数多于对照组,差异有统计学意义(P＜0.05);辐照组和对照组淋巴细胞凋亡数量和细胞周期的差异均无统计学意义(P＞0.05);辐照组细胞的趋化能力与对照组相比明显增加,差异有统计学意义(P＜0.05).结论 脾脏是EMP辐射的靶点之一.脾脏淋巴细胞数量的增加,可能是由于EMP改变了淋巴细胞的趋化迁移能力而导致的.     

微波暴露对原代培养大鼠海马神经元热休克蛋白家族表达的影响

目的 研究微波暴露对原代培养大鼠海马神经元中热休克蛋白(heat shock proteins,HSPs)表达调控的影响.方法 采用平均功率密度为90 mW/cm2微波辐照成熟的原代培养大鼠海马神经元10 min,于辐照后0、3、6、12、24 h提取细胞总蛋白,采用免疫印迹(Western blot)法检测HSP27、HSP70、HSP90和热休克转录因子(heat shock factor 1,HSF1)蛋白表达情况;于辐照后0、3、6、12、24 h分别提取细胞总RNA和总蛋白,采用实时定量聚合酶链反应(PCR)检测hsf1的mRNA表达水平;于辐照后20、40 min提取细胞核蛋白,凝胶迁移滞后实验(electrophoretic mobility shift assays,EMSA)法检测HSF1的活性变化.结果 90 mW/cm2微波辐照10 min后,HSP27蛋白表达水平在辐照后3、6、12 h分别明显升高22%、36%、18%,HSP70蛋白表达水平在辐照后3、6、12 h分别明显升高23%、32%、26%,与辐照前比较,差异均有统计学意义(P＜0.05,P＜0.01).HSP90蛋白表达水平在辐照后6、12 h分别明显升高27%、33%,与辐照前的差异亦有统计学意义(P＜0.05,P＜0.01).HSF1 mRNA和蛋白表达水平未见明显变化,但微波辐照可激活HSF1的DNA结合活力. 结论微波辐照后大鼠海马神经元发生热休克反应,被活化的HSF1在转录水平上调控HSPs的表达,从而发挥拮抗微波损伤的作用.     

维生素E对微波辐照后视网膜神经节细胞形态的影响

为探讨微波对体外培养的猪视网膜神经节细胞形态的影响及维生素 E(VE)的防护作用 ,为微波致视网膜损伤的研究提供一定的实验依据。用体外培养猪视网膜神经节细胞方法 ,光镜及电镜观察其形态结构 ,加入不同浓度 VE,用微波理疗机于微波屏蔽室内以 30 m W/ cm2 功率密度辐照 1h,辐照后立即于光镜下观察其形态变化 ,电镜观察其超微结构 ,比较辐照前后及加入 VE(10、2 0和 40 g/ L)后视网膜神经节细胞的变化。结果显示微波辐照后 ,细胞有聚集现象 ,部分细胞轴突消失 ,电镜可见线粒体及内质网肿胀 ,VE各组光镜下细胞形态变化不明显 ,电镜显示线粒体轻度肿胀 ,嵴完整。结果表明微波可引起视网膜神经节细胞形态损伤 ,VE可在一定程度上减轻微波对视网膜神经节细胞的损伤     

电磁辐射急性辐照致PC12细胞的损伤效应

目的探讨电磁辐射急性辐照对PC12细胞的影响.方法对离体培养的PC12细胞以65mW/cm2电磁波急性照射20min,于辐照后即刻、3、12、24h四个时相点检测细胞存活率、乳酸脱氢酶释放率,并采用Annexin-V-FITC及PI双标记流式细胞仪检测PC12细胞凋亡率.结果电磁波辐照后即刻PC12细胞存活率和LDH释放率变化不明显(P＞0.05),辐照后3h细胞存活率明显降低,而LDH释放率明显增加(P＜0.05),到24h后达到峰值(P＜0.01).电磁波辐照后即刻PC12细胞凋亡开始增加(P＜0.05),3h后凋亡细胞进一步明显增多,凋亡率约为20%,24h后细胞凋亡再次显著增加(P＜0.01).结论电磁辐射急性辐照后早期即可引起PC12细胞损伤,而在辐照后24h出现一种"继发损伤反应",细胞凋亡可能是电磁辐射辐照诱导PC12细胞损伤的主要原因之一.     

运动对慢性心理应激大鼠海马CA3区神经元细胞凋亡的影响

目的 观察运动对慢性心理应激大鼠海马CA3区神经元细胞凋亡的调节作用,探讨慢性心理应激致海马损伤的机制.方法 建立慢性心理应激模型,结合运动训练后,采用末端脱氧核苷酸转移酶介导的dUTP原位切口末端标记(TdT-mediated dUTP Nick-End Labeling,TUNEL)技术观察海马神经元细胞凋亡;利用免疫组织化学技术检测海马凋亡调控因子Bel-2、Bax的表达.结果 与对照组相比,应激组大鼠海马CA3区凋亡细胞数明显增加,差异有统计学意义(P＜0.01),其余各组的差异无统计学意义(P＜0.05).与应激组相比,30min运动组、60min运动组、应激+30min运动组以及应激+60min运动组神经元凋亡明显减少,差异有统计学意义(P＜0.05).与对照组相比,应激组Bcl-2表达明显降低,Bax表达明显升高,Bcl-2/Bax的比值明显降低;30min运动组、60min运动组Bel-2表达明显升高,差异有统计学意义(P＜0.05),Bax表达明显降低,Bcl-2/Bax的比值明显升高.与应激组相比,应激+30min运动组和应激+60min运动组Bcl-2表达明显升高,Bax表达明显降低,Bcl-2/Bax的比值明显升高.同时,慢性心理应激和运动训练对大鼠海马CA3区Bcl-2、Bax表达及Bcl-2/Bax比值的影响存在交互作用.结论 慢性心理应激导致大鼠海马CA3区神经元细胞凋亡增加,适量运动可抑制慢性心理应激引起的细胞凋亡,对海马有保护作用.     

锌对微波过氧化损伤的防护作用的实验研究

目的 :探讨微量元素锌对微波致视网膜神经节细胞的脂质过氧化损伤的防护作用 ,为进一步研究微波损伤机理及其防护提供一定的实验依据。方法 :体外培养猪视网膜神经节细胞 ,按微波辐照时间分为对照组、3 0 min组、6 0 min组 (辐照强度为 3 0 m W· cm-2 ) ,以及各辐照时间加锌组 ,2 4 5 0 MHz微波理疗机于微波屏蔽室内辐照 1 h,辐照后观察细胞形态 ,收集细胞 ,测定超氧化物歧化酶 (SOD)和丙二醛 (MDA)含量 ,测定细胞内锌含量。结果 :微波辐照后 ,细胞有聚集现象 ,部分细胞轴突消失 ,细胞 MDA含量明显增高 ,SOD降低 ,细胞内锌含量降低 ;加锌各组光镜下细胞形态变化不明显 ,MDA含量有所恢复 ,SOD含量增高 ,细胞内锌含量显著增高。结论 :微波可引起视网膜神经节细胞脂质过氧化损伤 ,锌可提高细胞的抗氧化能力 ,在一定程度上减轻微波对视网膜神经节细胞的过氧化损伤     

DNA聚合酶β表达水平对苯代谢物氢醌致细胞凋亡及线粒体膜电位的影响

目的 探讨DNA聚合酶β(DNA polymerase beta,polβ)对氢醌(HQ)所致细胞凋亡的影响及其可能的分子机制.方法 以polβ野生型(polβ+/+)、polβ缺陷型(polβ-/-)及polβ高表达型(polβoe)小鼠胚胎成纤维细胞为研究对象,以不同浓度的HQ溶液染毒后,采用流式细胞术分别检测HQ对细胞凋亡和线粒体膜电位( △Ψm)的影响,试剂盒法测定细胞内活性氧(ROS)和羟自由基(·OH)含量;化学发光法分析细胞内超氧化物歧化酶(SOD)和谷胱甘肽过氧化物酶(GSH-Px)活力.结果 与对照组相比,各染毒组凋亡细胞率和△Ψm降低的细胞比例明显增加,差异均有统计学意义(P＜0.05).与polβ+/+细胞比较,20.00、40.00、80.00 μmol/L染毒组polβ-/-细胞凋亡率明显增高,10.00、20.00、40.00、80.00μmol/L染毒组polβ oe细胞凋亡率明显降低,差异均有统计学意义(P＜0.05).与polβ+/+细胞(20.60％±0.57％、37.95％+0.64％、44.50％±1.27％、57.55％+1.06％)比较,10.00、20.00、40.00、80.00 μmol/L染毒组polβ-/-细胞△Ψm降低的细胞比例(33.60％±1.55％ 、46.05％±1.77％、52.75％±2.05％、75.20％±0.56％)明显增高,polβ oe细胞△Ψm降低的细胞比例(16.05％±1.20％、29.80％±1.21％、35.15％±1.06％、53.80％±0.85％)明显降低,差异均有统计学意义(P＜0.05).与polβ+/+细胞比较,各染毒组polβ-/-细胞产生的荧光强度明显增高,polβ oe细胞的荧光强度明显降低,差异均有统计学意义(P＜0.05).与polβ+/+细胞相比,20.00、40.00 μmol/L染毒组polβ-/-细胞内·OH含量明显增高,polβ oe细胞内·OH含量明显降低,差异有统计学意义(P＜0.05).在相同浓度HQ染毒剂量下,polβ-/-细胞内SOD和GSH-Px消耗最快,polβ oe细胞内的SOD和GSH-Px消耗速度缓慢.结论 HQ可诱导细胞产生ROS,降低△Ψm,从而介导凋亡的发生;polβ可以帮助细胞对抗ROS的产生,降低线粒体发生去极化的几率,从而对HQ介导的凋亡起到一定的保护作用.     

微波辐照对心肌细胞凋亡促进基因影响

目的探讨微波辐照诱导心肌细胞凋亡的分子病理机制。方法以功率密度峰值为950mW/cm2的脉冲微波辐照心肌细胞0,30,60,120s后,采用倒置显微镜观察心肌细胞形态,流式细胞仪及原位末端标记方法检测心肌细胞凋亡率,免疫组织化学方法检测多种凋亡相关基因表达的变化。结果辐照后心肌细胞呈现出典型的细胞凋亡形态。辐照60s后6,24h,心肌细胞凋亡率分别为（36.76±5.31）和（26.44±3.94）,与对照组（2.36±0.87）比较,差异有统计学意义（P〈0.01）。原位末端标记结果表明,心肌细胞凋亡率与辐照剂量呈正相关。凋亡促进基因Bax、P53、双向调控基因c-myc表达显著增强（P〈0.01）,凋亡抑制基因Bcl-2表达一过性增强,随后明显降低（P〈0.01）。结论心肌细胞是微波辐照损伤的敏感细胞,微波辐照可诱导心肌细胞凋亡,并存在剂量效应关系。Bcl-2/Bax、P53、c-myc参与微波辐照诱导的心肌细胞凋亡并发挥重要调控作用。     

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.