锰暴露不同时长对神经元细胞突触囊泡及其相关蛋白的影响

目的 研究锰暴露不同时长对神经元细胞突触囊泡及其相关蛋白的影响。 方法 将体外培养的神经元,分别用100 μM 锰处理0、6、12、18、24 h后,观察细胞活力及培养液中LDH的释放量,测定SNARE复合物相关蛋白的基因及蛋白表达,以及活动性突触囊泡的释放。 结果 神经元细胞用100 μM锰暴露不同时长后,神经元损伤逐渐加重(P<0.01);与对照组比较,Syntaxin 1A的基因及蛋白表达均未见明显改变(P>0.05),SNAP 25的基因和蛋白表达均逐渐下降(P<0.05),VAMP 2的基因和蛋白表达均逐渐升高(P<0.01),进而导致SNARE复合物蛋白形成先升高后下降的趋势,同时活动性突触囊泡的释放也出现相应改变。 结论 锰暴露可以时间依赖性的干扰SNARE复合物相关蛋白表达,减少了神经元细胞内SNARE复合物的形成,进而导致活动性突触囊泡减少,造成神经递质释放紊乱。     

钙蛋白酶拮抗剂Calpeptin对锰干扰突触体囊泡融合的保护作用

目的探讨钙蛋白酶拮抗剂Calpeptin对锰干扰突触体囊泡融合的保护作用。方法将24只小鼠随机分成4组,每组6只。对照组(腹腔注射0.9%氯化钠),低、高剂量染锰组(腹腔注射25μmol/kg、100μmol/kg氯化锰),Calpeptin预处理组(皮下注射Calpeptin 100μg/kg,30 min后腹腔注射100μmol/kg氯化锰),注射容量为2 ml/kg,每周5次,共4周。处死小鼠后分离基底核,制备突触体,测量小鼠基底核内锰含量,神经细胞内钙离子浓度和钙蛋白活力,突触体SNARE复合物及其相关蛋白的变化和囊泡融合情况。结果与对照组比较,高剂量染锰组小鼠基底核锰含量,神经细胞内钙离子浓度和钙蛋白酶活力显著增加;SNAP25蛋白表达下降,并出现裂解碎片,SNARE复合物形成减少,FM1-43荧光强度的下降;Calpeptin预处理可以明显抑制神经细胞内钙蛋白酶活力,缓解钙蛋白酶对SNAP25的裂解,100 k Da SNARE复合物也明显增多,而且SNARE复合物介导的突触囊泡融合有所上升。结论钙蛋白酶拮抗剂Calpeptin可以对锰干扰突触体囊泡融合起到有效的保护作用。     

MK-801对锰致神经元损伤的保护作用

[目的]研究不同浓度锰对原代培养神经元的损伤情况,同时用MK-801预处理,观察其对锰致神经元损伤的保护作用。[方法]选用原代培养神经元为模型,待细胞生长至最佳状态时,予以分组处理。染锰组为含不同浓度氯化锰25、100、400μmol/L的培养液,MK-801预处理组,用10μmol/LMK-801预处理30min后,再用400μmol/L氯化锰处理神经元,对照组为正常培养液,通过检测细胞活力、乳酸脱氢酶(LDH)释放量以及用TUNEL技术检测细胞凋亡的方法,评价MK-801对锰致神经元损伤的保护作用。[结果]用不同剂量锰处理神经元6～48h发现,神经元胞体固缩,突起断裂,网络消失。细胞活力和LDH释放量在同一染毒时间,随锰浓度升高细胞活力逐渐降低,LDH释放量逐渐升高;在同一锰浓度处理神经元,随着时间的延长细胞活力逐渐降低,LDH释放量逐渐升高。随锰浓度的升高,神经元细胞凋亡率和积分光密度均逐渐上升。用MK-801预处理30min后,400μmol/L锰处理神经元发现,与单纯用400μmol/L锰处理比较,细胞活力回升,LDH释放量降低,细胞凋亡率和积分光密度均有所下降。[结论]锰可以剂量依赖性和时间依赖性的对神经元造成损伤,促使细胞凋亡;MK-801可以在一定程度上有效地保护神经元。     

锰对神经元细胞内钙稳态影响的研究

目的研究锰对神经细胞内钙稳态的影响,重点观察神经元细胞钙离子浓度、Na+-K+-ATPase和Ca2+-ATPase活性的改变。方法选用原代培养神经元为模型,待细胞生长至最佳状态时,予以分组处理:锰处理组为含不同浓度氯化锰(0,25,100,400μmol/L)的培养液,培养神经细胞12h后,通过倒置相差显微镜观察细胞形态的改变,并检测神经元细胞内钙离子浓度、Na+-K+-ATPase和Ca2+-ATPase活性的变化。结果随着染Mn剂量的加大,神经元形态出现异常,细胞内钙离子浓度逐渐升高;细胞Na+-K+-ATPase和Ca2+-ATPase活性也逐渐下降。结论锰通过影响与维持钙稳态相关的酶(Na+-K+-ATPase和Ca2+-ATPase)活性,干扰神经元细胞内钙稳态,进而造成神经元细胞损伤。     

锰对新生大鼠神经细胞凋亡及葡萄糖调节蛋白78和CCAAT增强子结合蛋白同源蛋白表达的影响

目的 研究不同浓度锰对大鼠神经细胞凋亡及内质网应激信号分子葡萄糖调节蛋白78(GRP78)和CCAAT增强子结合蛋白同源蛋白(CHOP)mRNA与蛋白以及天冬氨酸特异性半胱氨酸蛋白酶-12(caspase-12)蛋白表达的影响.方法 以出生4～7 d的SPF级Wistar大鼠脑片为模型,分别用0(对照)、25、100、400 μmol/L锰暴露24h.检测培养液中乳酸脱氢酶(LDH)的释放量,神经细胞凋亡率以及神经细胞内GRP78、CHOP mRNA和蛋白及caspase-12蛋白的表达.结果 与对照组比较,100和400 μ,mol/L锰暴露组培养液中LDH的释放量均较高,而各浓度锰暴露组大鼠神经细胞凋亡率均较高,差异有统计学意义(P＜O.01);且随着锰暴露浓度的升高,培养液中LDH的释放量和大鼠神经细胞凋亡率均呈逐渐升高的趋势.与对照组比较,100和400 μmol/L锰暴露组神经细胞内GRP78mRNA及各浓度锰暴露组大鼠神经细胞内CHOP mRNA的表达均较高,而100、400 μmol/L锰暴露组神经细胞内GRP78和CHOP蛋白及各浓度锰暴露组大鼠神经细胞内caspase-12蛋白的表达也均较高,差异有统计学意义(P＜0.01);且随着锰暴露浓度的升高,大鼠神经细胞内GRP78、CHOP mRNA和蛋白及caspase-12蛋白的表达均呈逐渐升高的趋势.结论 锰可促使大鼠神经细胞凋亡及GRP78和CHOP表达升高.     

MK801抑制乐果诱导的大鼠皮层神经元凋亡的作用研究

目的通过应用N-甲基-D-天门冬氨酸(NMDA)受体非竞争性拮抗剂MK801探讨兴奋性氨基酸神经递质在乐果诱导的新生大鼠皮层神经元凋亡中发挥的作用。方法在纯化的新生鼠皮层神经元中,加入终浓度为100μmol/L的乐果,并用50和100μmol/L NMDA受体非竞争性拮抗剂MK801对100μmol/L乐果染毒组进行干预。染毒后48小时收获细胞,TUNEL染色检测神经元凋亡情况;HPLC-FLD方法测定细胞内兴奋性氨基酸递质含量,RT-PCR检测NMDA受体NR2B亚基mRNA表达的变化,荧光探针DCFH-DA试剂盒检测细胞内活性氧水平。结果在纯化培养的皮层神经元中,100μmol/L乐果染毒48h后,与对照组相比,Tunel染色强度为对照组1.40倍(P<0.01);兴奋性氨基酸的含量均上升(P<0.01);细胞内ROS水平逐渐增高为对照组的2.47倍(P<0.01)。对100μmol/L乐果染毒组给予50和100μmol/L MK801干预后,高剂量干预组凋亡减少为干预前的79.6%(P<0.01),EAA含量下降(P<0.01);细胞内ROS水平下降为干预前的88.9%和74.8%(P<0.01),但仍远高于对照组细胞内活性氧水平(P<0.01);NR2B mRNA表达上升为干预前的1.59和2.22倍(P<0.01),显著高于对照组水平(P<0.01)。结论兴奋性氨基酸递质和细胞内活性氧共同参与乐果诱导的神经元凋亡。NMDA受体阻断剂MK801不仅能减少活性氧的生成并能降低神经元兴奋性氨基酸含量,从而减少乐果诱导的神经元凋亡。     

锰对大鼠脑片的损伤及对细胞α-突触核蛋白表达的影响

目的研究锰对脑多巴胺神经细胞的毒性作用,重点观察α-突触核蛋白与细胞凋亡的改变。方法利用体外脑片培养模型,用不同浓度氯化锰(0,25,100,400μmol/L)处理脑片24 h后,观察脑片中酪氨酸羟化酶(tyrosine hydroxylase,TH)阳性细胞改变,培养液中乳酸脱氢酶(lactate dehydrogenase,LDH)的释放量,细胞凋亡率以及α-突触核蛋白的表达。结果随着Mn处理浓度的增加,脑片神经细胞损伤逐渐加重。与对照组比较,锰处理脑片导致TH阳性细胞数明显减少,LDH释放量、细胞凋亡率以及α-突触核蛋白的表达均明显增加。结论锰对多巴胺神经细胞有毒性作用,并且锰可以通过诱导α-突触核蛋白过表达而造成神经细胞损伤。 更多还原     

茶多酚对甲基汞致大鼠脑皮质神经元钙超载及N-甲基-D-天冬氨酸受体异常表达的拮抗作用

目的探讨茶多酚(tea polypheonols,TP)对甲基汞(methylmercury,Me Hg)所致大鼠大脑皮质神经元钙超载及N-甲基-D-天冬氨酸(N-methyl-D-aspartic acid,NMDA)受体异常表达的拮抗作用及机制。方法进行大鼠大脑皮质原代神经元培养,细胞成熟后给予0.01、0.1、1、2μmol/L Me Hg Cl分别染毒0.5、1、3、6、12 h,通过测定细胞活力选择1μmol/L Me Hg Cl暴露6 h作为Me Hg Cl染毒组进行TP预处理及其他指标测定。通过测定细胞活力选择5、10、20μmol/L TP预处理3 h作为TP预处理组,并测定神经元内ROS和游离Ca2+水平、钙蛋白酶活力及NR1、NR2A、NR2B m RNA和蛋白表达水平。结果与对照组比较,随着Me Hg Cl染毒剂量的升高,神经元细胞活力逐渐降低,呈剂量-效应关系,其中1μmol/L Me Hg Cl暴露6 h组的细胞活力为对照组的53.15%,接近IC50。TP预处理后,与1μmol/L Me Hg Cl暴露6 h组比较,10、20μmol/L TP预处理组细胞活力明显升高(P0.05或P0.01)。Me Hg Cl导致神经元ROS、细胞内游离Ca2+水平及钙蛋白酶活力升高,NR1、NR2A m RNA及蛋白表达水平降低,差异均有统计学意义(P0.05或P0.01);TP预处理对上述指标的拮抗呈剂量-效应关系,与1μmol/L Me Hg Cl组比较,神经元ROS、细胞内游离Ca2+水平及钙蛋白酶活力降低,NR1、NR2A m RNA及蛋白表达水平升高,差异均有统计学意义(P0.05或P0.01)。结论 TP对Me Hg所致大鼠脑皮质神经元毒性、细胞内钙超载及NMDA受体异常表达均有一定的拮抗作用。     

hOGG1基因在Cr(Ⅵ)诱导线粒体DNA氧化损伤中的作用

目的探讨hOGG1基因在Cr(Ⅵ)诱导线粒体DNA氧化损伤中的修复作用。方法取不同浓度的Cr(Ⅵ)(0、2、8和32μmol/L)处理L-02肝细胞24h,分别测定细胞内活性氧簇(ROS)与hOGG1 mRNA表达水平和线粒体内8-羟基脱氧鸟苷(8-OHdG)与hOGG1基因表达的人类8-羟基鸟嘌呤DNA糖苷酶蛋白(hOGG1蛋白)水平。结果 8μmol/L和32μmol/L剂量组与对照组比较,细胞内ROS平均水平及线粒体内8-OhdG平均水平均明显增加(P<0.05),而hOGG1基因mRNA水平和线粒体内hOGG1蛋白水平,与对照组比较,2μmol/L剂量组两者水平均上升(P<0.05),32μmol/L剂量组两者水平均降低(P<0.05)。结论 Cr(Ⅵ)可诱导细胞内ROS水平增加,引起线粒体DNA氧化损伤,而hOGG1基因表达水平的改变,影响了线粒体DNA的修复能力。hOGG1基因在Cr(Ⅵ)诱导线粒体DNA氧化损伤中起到了重要的作用。     

原花青素对宫颈癌HeLa细胞Caspase-3和Survivin基因表达的影响

目的 探讨原花青素对官颈癌HeLa细胞Caspase-3和Survivin基因表达的影响.方法 将按照不同终浓度原花青素(0,37.5μmol/L,75.0 μmol/L,150.0μmol/L,300.0μmo/L和600.0 μmol/L)处理宫颈癌HeLa细胞,分别纳入对照组(空白对照),37.5μmol/L PC组,75.0μmol/L PC组,150.0μmol/L PC组,300.0 μmol/L PC组和600.0 μmol/L PC组.继续培养24 h,收集细胞进行实验.采用RT-PCR检测Caspase-3 mRNA和Survivin mRNA表达变化.采取Western blot检测caspase-3和survivin蛋白表达的变化.采用比色法检测caspase-3相对活性.结果 随着原花青索浓度增加,Caspase-3 mRNA和caspase-3蛋白表达水平逐渐增加,而Survivin mRNA和survivin蛋白表达水平逐渐减少;随着处理官颈癌HeLa细胞原花青素浓度升高,caspase-3相对活性逐渐增加,且差异有显著意义(P＜0.05),在原花青素为600.0/μmol/L 时,活性最大.结论 原花青素可剂量依赖性地增加Caspase-3 mRNA和caspase-3蛋白表达水平及caspase-3活性,并且可剂量依赖性减少Survivin mRNA和survivin蛋白表达水平.     

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.