次声作用后大鼠脑皮质HSP70及超微结构的观察

目的探讨次声对鼠大脑作用的效应,观察次声不同时间作用后大鼠脑顶叶皮质热休克蛋白70及超微结构的情况。方法大鼠暴露于16Hz90dB的次声,2h/d,分组作用1d、7d、14d、21d、28d,免疫组织化学方法观察各组动物于次声暴露结束后2h、24h、48h、72h脑皮质HSP70的表达情况,透射电镜下观察各组动物于次声暴露结束后2h、72h脑皮质超微结构的变化。结果次声作用1d、7d组脑顶叶皮质未出现HSP70表达阳性神经元;14d、21d、28d组作用后2h出现表达,24h达高峰,72h消失。次声作用1d、7d、14d,脑皮质超微结构无明显变化;作用21d、28d,作用后2h超微结构出现变性改变,作用后72h逐渐恢复。结论一定次数的次声作用后大鼠脑皮质出现HSP70阳性神经元表达,且表达随时间呈动态改变,超微结构可见变性改变,随作用后时间延长可逐渐恢复。     

拟除虫菊酯对大鼠脑组织γ-氨基丁酸转氨酶活力的影响

目的　研究拟除虫菊酯对大鼠脑组织γ 氨基丁酸转氨酶 (GABAT)活力的影响。方法　应用偶联酶学紫外分光光度法 ,在体外和整体实验中 ,观察溴氰菊酯 (DM)和氯菊酯 (PM)对大鼠大脑皮层、海马、纹状体和小脑GABAT活力的影响。结果　在体外 ,终浓度为 10 -9～ 10 -4mol/L的DM或PM对大鼠大脑皮层、海马、纹状体和小脑的GABAT活力无明显影响 ;一次性经口给予 37.5mg/kg的DM组大鼠大脑皮层、海马和小脑的GABAT活力分别为 (2 .96± 0 .4 3)、(2 .13± 0 .4 4 )、(5 .12± 1.36 )nmol·mgpro-1·min-1,低于对照组 [(3.4 3± 0 .4 1)、(2 .6 8± 0 .4 7)、(6 .74± 1.6 4 )nmol·mgpro-1·min-1],差异有显著性 (P <0 .0 5 ) ,6 0 0mg/kgPM一次性染毒组大鼠大脑皮层和海马的GABAT活力分别为(4.5 7± 0 .30 )、(4.18± 0 .6 3)nmol·mgpro-1·min-1,高于对照组 ,差异有显著性 (P <0 .0 5 ) ;连续 5d每天 1次经口给予 12 .5mg/kg的DM或 2 0 0mg/kg的PM ,均对大鼠大脑皮层、海马、纹状体和小脑的GABAT活力无明显影响。结论　在体外 ,DM和PM均对大鼠脑组织GABAT活力无明显影响 ;在整体实验中 ,DM和PM对大鼠脑组织GABAT活力的影响可能存在差异。     

维生素E对静态负荷所致肌肉损伤保护作用的实验观察

目的观察家兔骨骼肌在静态负荷过程中血清肌酸激酶(CK)和乳酸脱氢酶(LDH)活力的变化,研究抗氧化剂维生素E对肌肉损伤的保护作用.方法将家兔分为3组,一组为空白对照组,另外两组家兔腰部施加一定的静态负荷,并给其中一组口服维生素E,分别于实验的不同时间取血,并测定3组动物血清中CK、LDH的活力.结果口服维生素E组与观察组动物血清CK活力都随实验时间的延长而升高,各个时点的血清CK活力与对照组相比,差异有显著性(P＜0.01);但维生素E组血清CK活力在6、9及12h时分别为(5880.3±1242.1)、(6756.7±1069.2)、(7800.0±506.4)IU/L,均低于观察组[(9693.7±2336.5)、(11862.3±3839.6)、(15812.5±2311.9)IU/L],差异有显著性(P＜0.01).观察组的LDH活力随时间延长而增高,3、6、9、12h时LDH活力分别为(380.8±49.5)、(398.5±96.5)、(433.2±107.9)、(414.7±96.9)IU/L,与对照组比较,差异有显著性(P＜0.05);维生素E组各个时点LDH活力与对照组相比,差异无显著性(P＞0.05).结论静态负荷可引起血清CK活力及LDH活力不同程度的升高,提示肌细胞膜通透性增高,骨骼肌有一定程度的损伤,维生素E对这类损伤有一定的保护作用.     

甲基汞急性暴露大鼠脑中汞蓄积及胆碱能神经递质改变的研究

目的 研究低剂量甲基汞短期暴露的神经毒性作用,为进一步探讨甲基汞早期神经毒性机制提供实验依据。方法 采用SD大鼠腹腔注射甲基汞,剂量分别为0．05、0．50及5．00mg／kg,并设对照组,分别暴露20min、1、4、24h时测定大鼠脑组织总汞含量、乙酰胆碱(ACh)含量及乙酰胆碱酯酶(AChE)活力。结果 除0．05mg／kg剂量组外,其余两组大鼠脑组织中汞含量在暴露20min就显著升高;0．05mg/kg组大鼠暴露4h后,脑汞含量也出现显著升高。各剂量组大鼠脑组织ACh及AChE都在暴露20min后就出现显著变化,并显示一定的剂量——效应和时间——效应关系。结论 甲基汞低剂量(0．05mg／kg)短时间暴露(20min)时脑组织ACh和AChE的改变表明此时可能启动了中枢神经系统某种调控机制。随暴露剂量和暴露时间增加,甲基汞蓄积于大鼠脑组织中,可引起脑组织ACh含量和AChE活力显著变化。     

移动电话微波辐射对体外培养大鼠皮层神经细胞损伤的研究

目的探讨移动电话微波辐射对体外培养大鼠皮层神经细胞的影响.方法在对体外新生大鼠(0～1d)大脑皮层神经细胞进行原代培养的基础上,以频率900MHz功率密度分别为0.025、0.050、0.100mW/cm2的模拟移动电话微波辐射4、8、12、16、20、24h.检测乳酸脱氢酶(LDH)活力及细胞死亡率.结果0.050mW/cm2功率密度组辐射12h、0.100mW/cm2功率密度组辐射8h后,均可引起神经细胞LDH活力和细胞死亡率增高,分别为(17.65±5.28)U/L、11.70%±2.67%,(19.24±3.71)U/L、14.62%±2.43%,与对照组[(12.98±2.54)U/L、8.93%±2.45%,(13.06±2.73)U/L、9.07%±1.87%]比较,差异有显著性(P＜0.01),且随着辐射时间的延长,LDH活力和细胞死亡率也逐渐上升;0.025mW/cm2功率密度组未见明显改变.结论长期连续的移动电话微波辐射对体外培养大鼠皮层神经细胞存在损伤作用.     

次声对小鼠肾上腺皮质束状带多边形细胞3-β羟甾脱氢酶和酸性磷酸酶的影响

目的研究次声对小鼠肾上腺皮质束状带多边形细胞酸性磷酸酶(acid phosphatase,ACP)、3-β羟甾脱氢酶(3-βhydroxysteroid dehydrogenase,3-βHSDH)的生物学效应。方法观察小鼠在频率8、16 Hz,不同声压级80、90、100、110、120、130 dB次声第1、7、14天暴露和停止暴露的14天后对肾上腺皮质束状带多边形细胞ACP、3-βHSDH的影响。结果单次1 h暴露,8 Hz组随声压级的升高,3-βHSDH活力增强,至130 dB时,出现酶活力异常降低,同时提示100 dB时出现多边形细胞损伤;16Hz组,80dB时小鼠3-βHSDH活力与对照组的差异无统计学意义(P>0.05),但已提示存在细胞损伤,100 dB时开始出现3-βHSDH活力增强,细胞损伤持续存在。持续次声暴露,8 Hz中、低声压级随暴露时间延长,3-βHSDH活力先增强后降低,高声压级时酶活力持续为低水平,中、高声压级均提示出现细胞损伤;16 Hz低声压级暴露表现同8 Hz低声压级,中、高声压级3-βHSDH活力持续降低,同时提示存在细胞损伤。8Hz、90 dB及130 dB次声连续暴露14 d后停止暴露,经14d间隔,多边形细胞表现为从有局部损伤迹象到有一定程度恢复,但原来暴露声压级越高,恢复程度越差。结论次声对小鼠肾上腺皮质束状带多边形细胞的生物学效应在一定作用强度范围内,可较明显地反映其频率作用特性;高强度、大剂量次声作用时,其特性常被严重的损伤效应所掩盖。脱离次声一段时间后,肾上腺皮质束状带的细胞有一定程度恢复,但原来暴露的声压级越高,恢复的程度越差。     

溴氰菊酯对大鼠神经系统的氧化应激作用

目的　观察溴氰菊酯(DM)在大鼠大脑皮层和海马组织诱导的脂质过氧化作用。方法　DM3.12 5、12 .5 0 0mg/kg染毒大鼠,测定其大脑皮层和海马组织丙二醛(MDA)水平和总超氧化物歧化酶(T SOD ,包括Mn SOD和CuZn SOD)、过氧化氢酶(CAT)、谷胱甘肽S 转移酶(GST)、谷胱甘肽过氧化物酶(GSH Px)和谷胱甘肽还原酶(GR)活力。脑组织细胞质碎片γ谷氨酰半胱氨酸合成酶(γGCS)活力和GSH含量用OPA柱前衍生反相高效液相色谱荧光法检测。结果　DM染毒5d ,(1) 12 .5 0 0mg/kgDM组大鼠大脑皮层MDA含量高于3.12 5mg/kgDM组,海马MDA含量高于对照组和3.12 5mg/kgDM组。(2 )两组DM染毒大鼠大脑皮层T SOD和CuZn SOD活力均低于对照组,差异均有统计学意义(P <0 .0 1或P <0 .0 5 )。(3) 12 .5 0 0mg/kgDM组大鼠大脑皮层GSH含量高于对照组,海马GSH含量低于对照组和3.12 5mg/kgDM组;3.12 5mg/kgDM组大鼠大脑皮层GR活力[(11.80±5 .15 )U/mgpro]低于对照组和12 .5 0 0mg/kgDM组[(18.98±3.6 8)、(17.35±2 .4 7)U/mgpro],3.12 5、12 .5 0 0mg/kgDM组大鼠海马GR活力[(2 1.4 6±8.89)、(2 1.6 3±4 .92 )U/mgpro]均低于对照组[(31.2 2±6 .97)U/mgpro];12 .5 0 0mg/kgDM组海马γGCS活力[(1.75±0 .6 0 )nmol·mgpro-1·min-1]低于对照组和     

孕哺期母鼠镧暴露所致仔鼠脑组织脂质过氧化及形态学改变的实验研究

目的探讨孕哺期母鼠镧暴露对子代大鼠脑组织的脂质过氧化作用及海马形态结构的影响。方法通过母鼠孕哺期染镧的方法检测子代断乳大鼠海马和大脑皮层组织丙二醛(MDA)含量、还原型谷胱甘肽(GSH)含量、谷胱甘肽过氧化物酶(GSH-Px)活力、超氧化物歧化酶(SOD)活力和总抗氧化能力(T-AOC);光镜下观察海马组织形态结构改变。结果随着剂量的增加子代大鼠海马和大脑皮质MDA水平明显升高,GSH含量和GSH-Px活力下降,脂质过氧化作用明显增强,T-AOC明显降低,海马组织形态结构发生病理性改变。结论孕哺期母鼠镧暴露对子代大鼠中枢神经系统具有损伤作用,其原因可能与脂质过氧化有关。     

长期铅暴露雄性大鼠脑组织铁过载及DNA氧化损伤

目的 研究铅暴露对不同生长阶段SD雄性大鼠脑组织铅、铁水平及DNA氧化损伤的影响.方法 将12只SPF级SD雌性大鼠随机分为3组,分别为空白对照(去离子水)组和低(0.8 g/L)、高(1.5 g/L)剂量乙酸铅染毒组,每组4只.采用自由饮水方式进行染毒,自妊娠前10d至仔鼠断乳(出生后21d).待断乳后,每组选取21只雄性仔鼠,相应各组分别自由饮用去离子水和0.3、0.9 g/L乙酸铅溶液.仔鼠分别饲养至断乳(21d)、中年(12个月)、老年(18个月)时,检测脑组织中铅、铁和8-羟基脱氧鸟苷(8-hydroxy-2'-deoxyguanosine,8-OHdG)的水平.结果 在同一生长阶段,随着铅染毒剂量的升高,大鼠脑铅、脑铁及脑组织8-OHdG水平均增加.线性回归分析结果显示,在断乳期和老年期,大鼠脑铁、脑8-OHdG水平随着脑铅水平的升高而上升(P＜0.05);同时,脑铅、脑铁联合作用使大鼠脑8-OHdG水平升高(P＜0.05).而中年期无明显改变.在空白对照组和各剂量铅染毒组中,随着铅染毒时间的延长,大鼠脑铅、脑铁水平均增高(P＜0.05).空白对照组中,脑8-OHdG水平在中年、老年期增高(P＜0.05);低剂量组改变不明显;高剂量组在老年期明显升高(P＜0.05),中年期改变不明显.结论 铅暴露可致SD大鼠脑组织铁过载及DNA氧化损伤.     

7,8-氧化苯乙烯对大鼠DA含量及MAO活力的影响

目的观察7,8-氧化苯乙烯(SO)在不同染毒剂量下对大鼠多巴胺(DA)神经递质含量及单胺氧化酶(MAO)活力的影响。方法采用wistar大鼠40只,随机分为4组,每组10只,雌雄各半。SO染毒剂量分别为1/4LD50(500mg/kg),1/8LD50(250mg/kg)和1/16LD50(125mg/kg)。空腹灌胃染毒,1次/d,持续染毒2周。染毒结束后取血及脑组织,测定DA含量及MAO活力。结果中剂量组大鼠血中MAO活力明显高于对照组,差异有统计学意义(P0.05);低、高剂量组大鼠血中MAO活力高于对照组,低、中、高剂量组脑中MAO的活力均比对照组增高,低、中、高剂量组脑中DA含量均低于对照组,但差异无统计学意义(P0.05)。结论 7,8-氧化苯乙烯可致血MAO活力升高,提示,单胺类递质的变化有可能参与了7,8-氧化苯乙烯的神经毒性作用。     

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.     

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.     

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.     

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.     

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.