鱼藤酮对星形胶质细胞谷氨酸摄取功能的影响

目的研究鱼藤酮对原代培养星形胶质细胞谷氨酸转运功能的影响。方法应用HPLC荧光法检测鱼藤酮染毒星形胶质细胞胞外Glu浓度,同位素标记法检测Glu摄取能力,采用RT-PCR与Western blot技术观察谷氨酸转运体基因及蛋白表达。结果鱼藤酮染毒星形胶质细胞胞外Glu浓度明显升高,Glu摄取能力显著降低,谷氨酸/天冬氨酸转运体(glutamate/aspartate transporter,GLAST)基因和蛋白表达均明显降低,而谷氨酸转运体-1(glutamatetransporter-1,GLT-1)蛋白表达升高。结论鱼藤酮可显著降低星形胶质细胞谷氨酸摄取功能,引起胞外Glu浓度升高;GLAST表达下调可能是鱼藤酮诱导胞外谷氨酸含量增加的主要原因之一,而GLT-1上调可能为神经细胞自我保护机制,以限制谷氨酸的神经毒作用。 更多还原     

增强缝隙连接耦联对鱼藤酮染毒星形胶质细胞谷氨酸代谢的影响

目的观察增强缝隙连接耦联对鱼藤酮染毒星形胶质细胞谷氨酸代谢的影响。方法体外培养大鼠中脑星形胶质细胞,随机分为对照组、鱼藤酮组(1.0μmol/L)、缝隙链接激动剂(AAP-10)干预组(50 nmol/L)和AAP-10干预组(250 nmol/L)。MTT法观察染毒星形胶质细胞活力,应用HPLC荧光法和同位素标记法检测星形胶质细胞外谷氨酸浓度和谷氨酸转运能力的变化,RT-PCR检测星形胶质细胞谷氨酸转运体(GLAST)mRNA的表达。结果鱼藤酮染毒组星形胶质细胞活力和谷氨酸转运能力明显降低,细胞外谷氨酸浓度明显增加;AAP-10干预组(250 nmol/L)星形胶质细胞活力有所升高,细胞外谷氨酸浓度明显降低,谷氨酸转运功能活性则明显增强,且GLAST mRNA表达明显上调。结论增强缝隙连接耦联能明显改善鱼藤酮所致星形胶质细胞外谷氨酸代谢紊乱,可能与其调控GLAST基因表达和功能活性有关。     

鱼藤酮对PC12细胞谷氨酸含量及其转运体表达的影响

目的观察鱼藤酮对PC12细胞的毒性与谷氨酸递质水平及谷氨酸转运体表达的关系。方法MTT法检测鱼藤酮染毒PC12细胞活力，高效液相色谱法测定染毒细胞胞外Glu含量，RT-PCR及Western blot技术检测谷氨酸转运体EAAC1 mRNA和蛋白表达。结果0．25μmol／L鱼藤酮染毒24h即可引起PC12细胞活力明显降低，LDH渗出量显著增加；0．5μmol／L以上鱼藤酮诱导PC12细胞释放Glu增加，谷氨酸转运体EAAC1基因及蛋白表达均显著降低。结论鱼藤酮引起神经细胞损伤可能与其增加Glu释放和降低谷氨酸转运体的表达有关。     

铅对原代培养星形胶质细胞谷氨酸转运体的影响

目的探讨铅暴露对星形胶质细胞(AS)中GLAST和GLT-1蛋白表达及转运体功能的影响。方法取出生1~3 d Wistar大鼠的仔鼠星形胶质细胞进行原代培养,以胶质纤维酸性蛋白(GFAP)染色鉴定细胞纯度后,进行0(对照组)、50、100、200及400μmol/L乙酸铅染毒,染毒时间为72 h。倒置显微镜下观察细胞形态并采集图像;以AlamarBlue法检测细胞活力;以Western blot法检测GLAST和GLT-1蛋白的表达;以同位素标记法测定谷氨酸转运体功能。结果 50和100μmol/L铅暴露组的细胞形态与对照组相比,未见明显改变;200μmol/L铅暴露72 h后,少量细胞开始脱壁,细胞间隙增大;400μmol/L铅暴露组细胞变大,突起变短或消失,脱壁细胞数量明显增多。与对照组相比,各浓度铅暴露组的AS活力均降低(P0.05),100、200和400μmol/L铅暴露组的GLT-1蛋白含量下降(P0.05),但各浓度铅暴露组的GLAST蛋白含量无显著改变。100、200和400μmol/L铅暴露组的3H-Glu放射性低于对照组,差异均有统计学意义(P0.05)。结论铅暴露可明显抑制AS中GLT-1蛋白的表达,并导致AS的Glu转运体功能下降。     

鱼藤酮对大鼠星形胶质细胞CaMKⅡ基因和蛋白表达的影响

目的 研究鱼藤酮对大鼠原代培养星形胶质细胞钙/钙调素依赖性蛋白激酶Ⅱ(CaMK Ⅱ)活性的影响.方法 MTT法检测染毒星形胶质细胞活力,激光共聚焦结合Fluo-4荧光法动态测定细胞内游离钙浓度([Ca2 ]i),采用RT-PCR技术检测CaMK Ⅱα和CaMK Ⅱβ mRNA的表达,Western-blot技术观察磷酸化CaMK Ⅱ蛋白活性的变化.结果 1.0和2.0 μmol/L鱼藤酮染毒时星形胶质细胞活力明显降低,染毒星形胶质细胞[Ca2 ]i呈浓度依赖性升高,CaMK Ⅱα亚基mRNA明显下调(P<0.05),CaMK Ⅱ蛋白活性显著降低(P<0.01).结论 鱼藤酮染毒星形胶质细胞内游离钙浓度的升高,CaMK Ⅱ基因表达和蛋白活性显著降低,可能是其诱导神经细胞变性损伤的重要原因之一.     

鱼藤酮对大鼠神经细胞谷氨酸代谢关键酶表达的影响

[目的]观察鱼藤酮对神经细胞谷氨酸代谢关键酶表达的影响. [方法]在体外建立星形胶质细胞与PCI2细胞共培养鱼藤酮染毒模型,采用RT-PCR法检测谷氧酰胺合成酶(glutamine synthetase,GS)与各氨酰胺酶(phosphate activated glutaminase,PAG)mRNA的表达,细胞免疫化学观察GS和PAG蛋白表达. [结果]随着染毒剂量的增加,星形胶质细胞GS mRNA的表达逐渐降低,GS阳性颗粒着色减弱;与对照组比较,0.5和1.0μmol/L鱼藤酮染毒组PCI2细胞PAG mRNA表达明显增强(P<0.05),PAG阳性产物强表达. [结论]鱼藤酮可干扰神经细胞谷氨酸代谢关键酶GS和PAG基因和蛋白表达,造成各氨酸代谢失衡.     

兴奋性氨基酸递质系统在乐果诱导星形胶质细胞活化中的作用

目的 探讨兴奋性氨基酸递质系统在乐果染毒后皮层星形胶质细胞活化中的作用.方法 新生大鼠皮层神经细胞传代3次后获得纯化的星形胶质细胞,分别加入终浓度为10-6、10-5、10-4mol/[的乐果,并用50和100 μmol/LN-甲基-N-天门冬氨酸(NMDA)受体非竞争性拮抗剂MK801对10-4mol/L乐果染毒组进行干预.染毒后48 h收获细胞,高效液相色谱-荧光检测系统(HPLC-FLD)方法测定细胞内兴奋性氨基酸递质含量,反转录聚合酶链反应(RT-PCR)法检测NMDA受体NR2B亚基、谷氨酸(Glu)、谷氨酸转运体(GLT-1)、天冬氨酸(Asp)、谷氨酸/天冬氨酸转运体(GLAST)、胶质纤维酸性蛋白(GFAP)及S100β mRNA表达的变化,免疫荧光染色半定量检测GFAP以及S100β的蛋白表达.结果 各剂量染毒组GLASTmRNA表达下降为对照组的67.8%、68.6%和76.2%,差异有统计学意义(P＜0.05);10-4 mol/L染毒组Glu、Asp含量与对照组相比明显下降,差异有统计学意义(P＜0.01);与对照组比较,10-4mol/L染毒组GFAP和10-5mol/L染毒组S100βmRNA表达,10-5、10-4mol/L染毒组GFAP蛋白表达,10-4mol/L染毒组S100β蛋白表达明显上升,差异有统计学意义(P＜0.01),有剂量依赖趋势.对10-4mol/L染毒组给予50和100 μmol/L MK801干预后,GLT-1、GLAST mRNA表达水平较10-4 mol/L染毒组明显上升,差异有统计学意义(P＜0.01),NR2B mRNA表达进一步升高,与未干预前相比,差异无统计学意义(P＞0.05),但均明显高于对照组水平,差异有统计学意义(P＜0.05,P＜0.01);100 μmol/L MK801干预后,Glu的含量升高为10-4mol/L染毒组的1.81倍,差异有统计学意义(P＜0.01);50和100μmol/LMK801干预后,GFAP转录及蛋白水平较未干预前明显下降,差异有统计学意义(P＜0.01),50 μmol/L干预组S100β蛋白表达水平仍然高于对照组,差异有统计学意义(P＜0.01).结论 乐果对兴奋性氨基酸递质系统的影响参与了星形胶质细胞的活化;NMDA受体阻断剂MK801有助于控制星形胶质细胞胶质化.

Abstract：

Objective To study the involvement of excitatory amino acid system in astrocytes activation caused by dimethoate. Methods Pure-cultured astrocytes were gained by three passages from primary cultured rat nerve cells, then treated with 10-6,10-5,10-4 mol/L dimethoate for 48 h, 50 μmol/L and 100μmol/L MK801, a NMDA receptor blocker, was used to intervene the effects induced by 10-4 mol/L dimethoate.HPLC-FLD was utilized to measure the concentrations of excitatory amino acid (EAA), RT-PCR was used to detect the expression levels of NR2B, GLT-1, GLAST, GFAP and S100β mRNA, and immunofluresence staining method was applied to measure the expression levels of GFAP and S100β proteins. Results The expression levels of GLAST mRNA in all exposure groups were 67.8% ,68.6% and 76.2% of control level,respectively, which were significantly lower than that of control group (P＜0.05); The concentrations of EAA significantly decreased in 10-4 mol/L dimethoate group, as compared with control group (P＜0.01); the expression levels of GFAP mRNA in 10-4 mol/L dimethoate group, of S100β mRNA in 10-5 mol/L dimethoate group, of GFAP protein in 10-4 mol/L and 10-5 mol/L dimethoate groups and S100β protein in 10-4 mol/L dimethoate group were significantly higher than those in control group (P＜0.01). The expression levels of GLT-1 and GLAST mRNA in 10-4 mol/L dimethoate plus 50 μ mol/L or 100 μ mol/L MK801 groups increased significantly, as compared with 10-4 mol/L dimethoate group (P＜0.01), the expression levels of NR2B mRNA in 10-4 mol/L dimethoate plus 50 μ mol/L or 100 μmol/L MK801 groups increased significantly, as compared with control group (P＜0.05 or P＜0.01); the concentration of Glu in 10-4 mol/L dimethoate plus 100 μ mol/L MK801 group increased significantly, as compared with 10-4 mol/L dimethoate group (P＜0.01); the expression levels of GFAP mRNA and protein in10-4 mol/L dimethoate plus 50 μ mol/L or 100 μ mol/L MK801 groups decreased significantly (P＜0.01); S100β protein expression level in 50 μ mol/L MK801 intervention group was significantly higher than thatl in control group (P＜0.01). Conclusion Excitatory amino acid system involved in astrocytes activation caused by dimethoate. MK801 was useful to control astrocytes gliosis.     

鱼藤酮对星形胶质细胞内游离钙浓度的影响及其机制

[目的]研究鱼藤酮引起的星形胶质细胞内游离钙浓度变化及其离子流动机制. [方法]以体外培养的大鼠中脑星形胶质细胞为研究对象,激光共聚焦结合Fluo-4荧光法动态测定细胞内游离钙浓度.[结果]鱼藤酮可浓度依赖性地引起星形胶质细胞内游离钙浓度升高.细胞内钙库释放抑制剂TMB-8、无钙缓冲液和钙通道阻滞剂MK-801、尼莫地平均可抑制鱼藤酮引起的细胞内钙浓度变化,但其抑制作用发挥的时间和程度均有显著不同. [结论]细胞内钙释放与细胞外钙内流共同参与了鱼藤酮引起的星形胶质细胞内游离钙浓度的升高,但细胞内钙释放发挥作用的时问稍迟,而鱼藤酮引起的细胞外钙内流主要由电压依赖武钙通道内流引起.     

脑出血中谷氨酸及其转运体的参与

在中枢神经系统中谷氨酸(Glutamate,Glu)含量丰富,是重要的兴奋性神经递质。在脑血管性疾病等病理情况下,Glu大量释放,其摄回系统因能量合成不足等原因被广泛抑制,甚至起到反作用。过量积聚的Glu在神经细胞外产生兴奋性毒性,最终导致神经元损伤、死亡。脑细胞外不存在Glu代谢酶,Glu的回收基本由突触前神经元和其周围星形胶质细胞膜上的谷氨酸转运体1(Glutamate transporter-1,GLT-1)完成,其中发挥主要作用的是GLT-1。脑出血时Glu的细胞外聚集已经有越来越多的证据,作用不容忽视。针对GLT-1的有关研究大多集中在脑缺血时,针对脑出血的研究较少。该文综述了脑出血时Glu及GLT-1的参与情况。     

鱼藤酮对星形胶质细胞缝隙连接耦联功能的影响

目的观察鱼藤酮对星形胶质细胞缝隙连接耦联功能的影响。方法建立星形胶质细胞与常用的神经细胞株PC12细胞共培养鱼藤酮染毒模型,应用划痕染料标记示踪技术观察染毒星形胶质细胞缝隙连接耦联功能的变化,采用RT-PCR法检测CX43 mRNA的表达,Western Blot技术观察CX43蛋白活性变化。结果随着染毒剂量的增加,鱼藤酮对星形胶质细胞缝隙连接耦联功能的抑制作用愈发明显;与正常对照组比较,0.5、1.0μmol/L鱼藤酮染毒组CX43 mRNA和蛋白表达均显著降低(P<0.01)。结论鱼藤酮可引起星形胶质细胞CX43表达水平降低,显著抑制细胞缝隙连接耦联功能,这可能是其诱导神经细胞损伤的原因之一。     

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.