甲醛致小鼠肺DNA蛋白质交联和DNA断裂效应的研究

目的 研究甲醛致小鼠肺DNA-蛋白质的交联（DNA-protein crosslinks．DPC）和致DNA的断裂作用。方法以小鼠肺为材料,经体外染毒后．采用KCl-SDS沉淀法和单细胞凝胶电泳法检测液态甲醛染毒后肺部提取细胞中DNA-蛋白质交联物的含量及DNA的断裂效应。结果KCl-SDS沉淀法,低浓度的液态甲醛（5μM,25μM）不能引起DNA-蛋白质的交联（P〉0．05）,较高浓度（125μM．625μM）可以引起明显的DNA-蛋白质的交联作用（125μM,p〈0．05;625μM．P〈0．01）。而单细胞凝胶电泳法显示甲醛在低浓度（5μM,25μM）时可以引起DNA链的断裂（P〈0．01）．在较高浓度（125μM,625μM）时可以引起交联作用（P〈0．01）。结论甲醛在较高浓度时可以导致明显的DNA-蛋白质交联作用．而在〈25μM时以DNA断裂为主。     

甲醛致大鼠离体骨髓细胞DNA-蛋白质交联的研究

目的检测经不同浓度甲醛染毒后所致大鼠骨髓细胞的DNA-蛋白质交联程度。方法采用KCl-SDS沉淀法检测液态甲醛所致DNA-蛋白质交联（DPC）效应。结果低浓度的甲醛（10μmol／L和50μmol／L）能引起DNA-蛋白质的交联;较高浓度的甲醛（250μmol／L和1250μmol／L）可以产生明显的DNA-蛋白质交联作用（P〈0．01）。结论甲醛可造成骨髓细胞DNA-蛋白质交联,而DPC可以对细胞产生严重的遗传毒性,这可能是甲醛导致白血病的分子机制之一。     

甲醛致V79细胞DNA-蛋白质交联作用及其修复

目的探讨甲醛诱导DNA-蛋白质交联作用及其修复效应。方法采用培养V79细胞株作为实验材料,以不同浓度的液态甲醛(0、50、100、200、400、800、1 600μmol/L)对细胞染毒1 h后检测DPC率,并根据实验结果选取200μmol/L对培养细胞株进行修复实验(修复0、6、12、18、24 h)。采用KCl-SDS沉淀法检测DPC率。结果较高浓度的液态甲醛(≥200μmol/L)可以产生明显的DPC效应(P<0.05);由200μmol/L浓度的液态甲醛诱导V79细胞产生明显的DPC(P<0.05),经过修复可以恢复到空白对照水平(P>0.05)。结论较高浓度的甲醛可以明显诱导DPC形成,甲醛所致的DNA-蛋白质交联可以得到修复。 更多还原     

邻苯二甲酸丁基苄酯诱发HeLa细胞株DNA-蛋白质交联影响的初步研究

目的研究邻苯二甲酸丁基苄酯（BBP）的遗传毒性。方法采用不同浓度BBP（0、5、25、125、625μmol·L^-1）对HeLa细胞进行体外染毒2h,利用KCl-SDS沉淀法检测DNA-蛋白质交联DPC效应。结果不同浓度的BBP均能引起HeLa细胞DPC系数的上升,但这种效应在低浓度（5μmol·L^-1）时不显著（P〉0.05）;而在高浓度（25、125、625μmol·L^-1）时,BBP能够显著地或非常显著地（P〈0.01,P〈0.05）诱导HeLa细胞产生DNA-蛋白质交联效应。结论邻苯二甲酸丁基苄酯可诱发HeLa细胞株DNA-蛋白质交联。     

甲醛致大鼠肺和肾组织细胞DNA-蛋白质交联及其修复研究

目的为探讨甲醛致生物机体DNA-蛋白质交联(DPC)作用及其修复能力。方法以3月龄SPF级健康成年雄性Wistar大鼠为实验动物分别进行体内(0、0.5、1.0、3.0mg/m3气态甲醛吸入染毒72h)和体外实验(0、25、50、100、150、200μmol/L液态甲醛染毒1h),并进行体内(3.0mg/m3的气态甲醛吸入染毒72h)和体外(75μmol/L的液态甲醛染毒1h)修复实验(修复0、6、12、18和24h)。采用KCl-SDS沉淀法检测大鼠肺、肾组织细胞DPC率。结果体内实验表明,低浓度的气态甲醛(0.5mg/m3)不能明显诱导大鼠肺、肾组织细胞产生DPC,较高浓度的气态甲醛(≥1.0mg/m3)可以产生明显的DPC作用(P<0.05);由3.0mg/m3浓度的气态甲醛使肺、肾组织细胞产生的DPC可在24和18h内得到修复,并可在24h内恢复到空白对照水平。体外实验表明,低浓度的液态甲醛(25μmol/L)不能明显诱导大鼠肺、肾组织细胞产生DPC,较高浓度的液态甲醛(≥50μmol/L)可以产生明显的DPC作用(P<0.05);由75μmol/L浓度的液态甲醛使肺、肾组织细胞产生的DPC可以在1...     

微囊藻毒素-LR致小鼠肝、肾和睾丸细胞DNA-蛋白质交联的研究

目的探讨微囊藻毒素-LR所致小鼠肝、肾、睾丸细胞DNA-蛋白质交联(DPC)作用。方法以昆明种雄性小鼠为实验对象,腹腔注射染毒,采用KCl-SDS沉淀法检测小鼠肝、肾、睾丸细胞中交联DNA和游离DNA的量,计算其DPC系数,DPC系数=交联DNA/(交联DNA+游离DNA),判断DNA与蛋白质的交联程度。结果在小鼠肝细胞中,微囊藻毒素-LR各染毒组DPC数量均有显著增加,其DPC系数与对照组相比差异均有显著性(P<0.05)。在小鼠肾细胞中,微囊藻毒素-LR染毒剂量为3μg/kgbw和6μg/kgbw时,DPC数量显著增加,其DPC系数与对照组相比差异有显著性(P<0.05);染毒剂量为12μg/kgbw时,DPC数量未增加,其DPC系数与对照组相比差异无显著性(P>0.05)。在小鼠睾丸细胞中,染毒剂量为3μg/kgbw时,DPC数量未增加,其DPC系数与对照组相比差异无显著性(P>0.05)。染毒剂量为6μg/kgbw和12μg/kgbw时,DPC数量显著增加,其DPC系数与对照组相比差异有显著性(P<0.05)。结论在一定的染毒剂量下,微囊藻毒素-LR可以引起小鼠肝、肾、睾丸细胞DNA-蛋白质交联。     

甲醛致雄性大鼠脑和睾丸细胞DNA-蛋白质交联的研究

目的探讨气态甲醛致雄性大鼠脑细胞和睾丸细胞DNA-蛋白质交联（DNA-protein crosslinks,DPC）作用。方法将24只SPF级Wistar雄性大鼠随机分为4组,每组6只,分别为0.5、1.0、3.0mg／m。气态甲醛染毒组和阴性对照组。连续动态吸入染毒72h后,应用KCl-SDS沉淀法检测大鼠脑和睾丸组织DNA-蛋白质交联的含量。结果与阴性对照组比较,0.5mg／m^2气态甲醛染毒组大鼠脑和睾丸组织的DPC系数差异无统计学意义（P〉0.05）,随着甲醛浓度的增加,DPC系数逐渐升高。与阴性对照组比较,1.0、3.0mg／m^3气态甲醛染毒组大鼠脑和睾丸组织DPC系数升高,差异有统计学意义（P〈0.01）结论低浓度（0.5mg／m^3）的气态甲醛不能引起大鼠脑和睾丸组织产生DPC效应,而较高浓度（1.0、3.0mg／m^3）的气态甲醛可明显诱导其产生DPC效应,造成严重的DNA损伤。     

甲苯二异氰酸酯致中国仓鼠肺细胞DNA交联作用

目的 研究甲苯二异氰酸酯(TDI)诱导中国仓鼠肺细胞(CHL)DNA的交联作用,探讨TDI的遗传毒性.方法 在培养的CHL细胞中分别加入浓度为0.64,1.28,2.56 μmol/ml的TDI进行染毒,用荧光分光光度法检测细胞内的DNA-DNA交联水平,用氯化钾-十二烷基硫酸钠(KCI-SDS)沉淀法检测细胞内的DNA-蛋白质交联水平.结果 低浓度的TDI不能致DNA-DNA交联(DDC)和DNA-蛋白质交联(DPC)(P>0.05);随着染毒浓度的增加,其DDC率和DPC率也随之升高,高剂量组的DDC为54.97%(P<0.01),DPC为29.06%(P<0.0).结论 一定剂量的TDI能诱导细胞内DNA交联作用.     

邻苯二甲酸二乙基己酯致小鼠不同器官细胞 DNA-蛋白质效应研究

目的为了探讨邻苯二甲酸二乙基已酯（DEHP）导致生物机体内不同器官DNA-蛋白质的交联（DPC）作用。方法以采用KCl-SDS沉淀法来检测DEHP体外染毒后昆明纯系小鼠体内肝、脑、睾丸、肺等4个器官的细胞中DNA-蛋白质交联含量。结果当DEHP的浓度为5μM时,小鼠肝细胞的DPC系数与对照组相比没有发生显著的变化;当DEHP的浓度分别升高到10、20、40和80μM时,DPC系数显著上升,且DPC含量与对照组相比有极显著差异;在脑细胞中,当DEHP的浓度分别为5、10μM时,能显著诱导DPC的生成（P〈0．05）,但是,随着DEHP的浓度升高,DPC的含量与对照组相比没有显著性差异;在睾丸的细胞中,当DEHP的浓度为5μM时,小鼠睾丸的细胞DPC系数与对照组相比有显著的升高（P〈0．05）;当DEHP的浓度升高到10、20、40、80μM时,DPC系数显著上升,且DPC含量与对照组相比有极显著差异（P〈0．01）;在肺细胞中,DEHP的浓度为5μM时,就能显著诱导DPC的生成（P〈0．05）。结论DNA-蛋白质交联是一种严重的DNA损伤。DEHP可诱导DNA-蛋白质交联的产生。     

姜黄素对甲醛致A549细胞DNA-蛋白质交联损伤的拮抗作用

为探讨姜黄素对甲醛致A549细胞DNA-蛋白质交联(DPC)的拮抗效应,采用培养A549细胞株作为实验材料,分为正常对照组、0.1 mmol/L甲醛组、姜黄素拮抗组(2.5、5.0、10.0、20.0 mg/L姜黄素+0.1 mmol/L甲醛组),对细胞染毒4 h后采用氯化钾-十二烷基硫酸钠沉淀法检测DPC率。结果显示,0.1 mmol/L甲醛染毒组DPC率高于对照组(P0.05),各姜黄素拮抗组DPC率均低于0.1 mmol/L甲醛组,但2.5、5.0、10.0 mg/L姜黄素拮抗组的DPC率高于对照组,差异均有统计学意义(P0.05),20.0 mg/L姜黄素拮抗组DPC率与对照组差异无统计学意义(P0.05)。提示较高浓度的姜黄素可以拮抗甲醛所致的DNA-蛋白质交联损伤。     

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.