Bcl-2家族蛋白在维生素E琥珀酸酯诱导人胃癌细胞凋亡中的作用

目的:研究Bcl-2家族蛋白在维生素E琥珀酸酯(RRR-α-tocopheryl succinate,α-TOS;vitamin E succinate,VES)诱导人胃癌SGC-7901细胞凋亡线粒体途径中的作用。方法:采用噻唑蓝(MTT)法测定VES对SGC-7901细胞的半数抑制浓度(IC50值);吖啶橙/溴化乙啶(AO/EB)染色观察细胞凋亡;Mito Tracker Red CMXRos染色观察线粒体膜电位(ΔΨm)的改变;Western Blot法检测不同剂量VES对人胃癌SGC-7901细胞Bid、Bax、Bcl-2蛋白表达和细胞色素C(cytochrome C,Cyt C)蛋白表达与定位的影响。结果:VES对SGC-7901细胞的IC50值为101.45μg/ml;VES可引起SGC-7901细胞发生凋亡和线粒体膜电位下降;并引起Cyt C蛋白在细胞内重新定位、Bid蛋白剪切活化、Bax蛋白表达增加和Bcl-2蛋白表达减少。结论:VES可抑制SGC-7901细胞的生长,并通过线粒体途径诱导凋亡,其机制可能是通过剪切活化Bid蛋白、上调Bax/Bcl-2相对水平来实现的。     

维生素E琥珀酸酯对人胃癌细胞中核因子及抗凋亡基因的影响

目的本研究以人胃癌SGC-7901细胞为肿瘤模型,在体外探讨维生素E琥珀酸酯(VES)在抑制肿瘤细胞生长、诱导细胞凋亡过程中对NF-κB组成性激活及抗凋亡基因在转录水平上的调控作用。方法采用MTT法和AnnexinV法分别检测不同浓度水平VES处理人胃癌SGC-7901细胞后细胞的生长和凋亡情况。采用细胞成分分离法获得细胞核总蛋白,然后以Westernblot法测定VES处理后核因子蛋白p65在细胞核总蛋白中的含量。用RT-PCR方法检测VES对SGC-7901细胞中抗凋亡基因c-IAP1、c-IAP-2、NAPI、survivin、XIAP的转录调节作用。结果12.5～50.0μmolVES作用24h后,SGC-7901细胞的生长被明显抑制。50μmolVES作用于细胞12h后可诱导细胞发生凋亡,且作用48h后其凋亡诱导作用更明显。Westernblot结果发现,VES处理SGC-7901细胞后使细胞核内NF-κBp65蛋白的含量下降,即抑制了NF-κBp65向细胞核内的迁移。RT-PCR结果提示,VES处理胃癌细胞后可以在基因水平上抑制抗凋亡基因NAIP和survivin转录,对其他IAPs家族成员-c-IAP1、c-IAP-2、XIAP的转录无下调作用。结论VES对SGC-7901细胞内NF-κB组成性激活的调控作用及对抗凋亡基因在转录水平上的抑制作用可能是其抑制SGC-7901细胞生长、诱导细胞发生凋亡的机制之一。     

c-Jun N-末端激酶在维生素E琥珀酸酯诱导人胃癌细胞凋亡中的作用

c-Jun N-末端激酶(c-Jun N-terminal kinase，JNK)属于丝裂素活化蛋白激酶(mitogen-activated protein kinases，MAPK)家族成员，多种细胞外应激信号可使其磷酸化而活化，在细胞应激反应中起重要作用。我们通过研究维生素E琥珀酸酯(vitamin E succinate，VES)对人胃癌SGC-7901细胞中JNKMAPK表达的影响，探讨该途径在VES诱导SGC-7901细胞凋亡中的作用。     

α-生育酚琥珀酸酯的合成及抑制肿瘤作用

目的合成α-生育酚琥珀酸酯(α-Tocopherol succinate，α-TOS)，验证其对人胃癌细胸SGC-7901的生长抑制作用，并研究其发挥作用的分子形式。方法利用α-生育酚(α-Tocopherol，α-TOH)和琥珀酸酐在催化剂的作用下合成α-TOS，用噻唑蓝[3-(4，5-dimethyl—thiazol-2-y1)-2，5-diphenyl tetrazolium bromide MTT]法观察其对SGC-7901细胞增殖的影响，应用琼脂糖凝胶电泳检测α-TOS对SGC-7901细胞洲亡的诱导作用．并利用高效液相色谱(High Performance Liquid Chromatography，HPLC)法检测α-TOS抑制癌细胞生长的作用形式。结果经红外光谱和质谱分析鉴定，本研究合成的α-TOS与标准品一致；与对照组相比，10和20μg／ml剂量组的α-TOS对SGC-7901细胞增殖的抑制作用明显，处理第6d时，癌细胞的生存率分别降至21．7％和7．7％；10和20μg／ml的α-TOS处理SGC-7901细胞48h后，琼脂糖凝胶电泳检测到细胞发生凋亡时DNA降解形成梯形分子条带；在生长受到抑制的SGC-7901细胞及其培养体系中，利用HPLC法仪检测到α-TOS，均未检测到其水解产物α-TOH。结论α-TOS合成品对SGC-7901细咆具有明显剂量依赖的抑制增殖和诱导凋亡作用，且α-TOS以不分解的整体分子形式抑制肿瘤细胞生长。     

维生素E琥珀酸酯诱导胃癌细胞凋亡

目的 探讨维生素E琥珀酸酯(VES)诱导人胃癌SGC-790l细胞凋亡执行阶段的机制。方法 分别将对照组0．1％无水乙醇和5，10，20μg／m1 VES加入培养液中，24h后通过荧光染色观察细胞核形态和线粒体跨膜电位(△ψm)改变，并用Westem蛋白印记检测凋亡诱导因子在线粒体和细胞质中的重新分布。结果 VES可明显诱导人胃癌SGC-790l细胞凋亡，20vg／m1 VES可使细胞凋亡率达到49．7％，伴有△ψm的明显降低，并有凋亡诱导因子自线粒体中的释放。结论 VES可能是通过使线粒体通透性改变，降低△ψm并释放线粒体中的凋亡诱导因子，诱导SGC-790l细胞凋亡。     

FADD在VES诱导人胃腺癌细胞凋亡中的作用

目的 了解带有死亡结构构成的Fas相关蛋白（FADD）在维生素E琥珀酸酯（VES）诱导胃腺癌细胞凋亡过程中的作用。方法 以人胃腺癌SGC－7901细胞作为靶细胞，采用WesternBlot法、Lipofect转染、DAPI染色法探讨FADD在VES诱导SGC－790细胞凋亡过程中的作用。结果 经不同剂量VES处理后，SGC－7901细胞中FADD蛋白表达增加，呈剂量－效应关系；该细胞经FADD反义寡核苷酸转染与正我寡核苷酸杂上比，VES处理的细胞中FADD蛋白表达下降；用FADD反义寡核苷酸转染SGC－7901细胞后，降低了VES诱导的细胞凋亡率。结论 FADD在VES诱导SGC－7901细胞凋亡过程中起着重要的作用。     

阻断泛素-蛋白酶体通路对胃癌细胞株SGC-7901 DNA合成及细胞周期的影响

目的 研究阻断泛素-蛋白酶体通路对胃癌细胞株SGC-7901 DNA合成及细胞周期的影响。方法 将泛素-蛋白酶体通路特异性阻断剂MG-132加入胃癌细胞株SCC-7901，^3H-TdR掺入试验测定对胃癌细胞DNA合成的影响。流式细胞仪(FCM)检测细胞周期。结果 MG-132作用于胃癌细胞株SGC-7901后，细胞DNA合成显著受抑制，G0／G1期细胞比例增加，S、G2／M期细胞比例减少。结论 MG-132能显著抑制胃癌细胞株SGC-7901的DNA合成，使细胞产生G1期阻滞，表明阻断泛素-蛋白酶体通路可能是治疗胃癌的新思路。     

曲古菌素A对胃癌细胞SGC-7901增殖抑制的研究

目的:研究组蛋白去乙酰化酶抑制剂曲古菌素A(TSA)对胃癌细胞SGC-7901增殖活性的抑制作用。方法:采用不同浓度的TSA处理胃癌细胞SGC-7901,MTT法检测药物作用前后的细胞增殖情况。流式细胞仪检测TSA处理前后细胞周期的变化。结果:75 ng/ml TSA在48 h时就出现明显抑制胃癌细胞SGC-7901的增殖。抑制由12 h至72 h显著增加,细胞周期检测发现75 ng/ml TSA即可导致细胞G2期阻滞,抑制细胞增殖。结论:TSA可抑制体外胃癌细胞SGC-7901的生长,诱导SGC-7901细胞出现G2期阻滞。     

维生素E琥珀酸酯诱导人胃癌细胞凋亡中线粒体的作用

目的探讨在维生素E琥珀酸酯(vitaminEsuccinate,VES)诱导人胃腺癌SGC7901细胞凋亡过程中线粒体的作用。方法SGC7901细胞经5、10、20μgmlVES处理后,用荧光染色法观察线粒体跨膜电位(Δψm)改变,用WesternBlot法检测细胞质中细胞色素c的表达情况和caspase3的表达与激活。结果VES可使线粒体Δψm明显降低,有明显的剂量效应和时间效应关系。胞质中细胞色素c和caspase3表达增加,同时激活caspase3。结论VES可能是通过使线粒体通透性改变并释放细胞色素c,激活下游caspase3,从而诱导SGC7901细胞凋亡。     

药物代谢酶维生素E琥珀酸酯抑制苯并(a)芘

目的　探讨药物代谢酶在维生素E琥珀酸酯 (VES)抑制苯并 (a)芘毒性中的作用。方法　建立B(a)P诱导的小鼠前胃癌模型 ,观察不同途径投予VES对前胃癌的抑制作用。再选择最佳途径观察两相药物代谢酶在此过程中的变化。采用免疫荧光光度法检测小鼠肝脏微粒体 (S - 9组分 )中Ⅰ相药物代谢酶乙氧基异吩恶唑 0 -脱乙基酶(Ethoxyresorufin 0 -deethylase,EROD)活性 ;应用试剂盒测定S - 9组分中Ⅱ相药物代谢酶谷胱甘肽 -S -转移酶(GST)活性。结果　经口投予和腹腔注射VES均可明显降低B(a)P诱导的小鼠前胃癌的发生。VES可显著降低肝脏Ⅰ相药物代谢酶乙氧基异吩恶唑 0 -脱乙基酶 (EROD)的活性 (39 1± 3 0 5 ) ,与阳性对照组 (5 7 9± 3 16 )比较 ,有显著性差异。结论　VES可降低B(a)P诱导的小鼠前胃癌 ,作用机制可能是通过影响肝脏药物代谢酶的活性来实现。     

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.     

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.