镍冶炼烟尘对中国仓鼠肺细胞毒性和细胞间隙连接通讯的影响

目的探讨镍冶炼烟尘对中国仓鼠肺细胞（CHL）毒性和细胞间隙连接通讯（GJIC）的影响。方法以CHL细胞为靶细胞，采用噻唑蓝（MTT）颜色反应法，检测2份镍冶炼烟尘对CHL细胞的毒性作用。采用划痕标记染料示踪技术（scrape-loading and dye transfer，SLOT）检测镍冶炼烟尘对CHL细胞GJIC的影响。结果2份受试物各剂量组在作用6、12h时，CHL细胞增殖情况与对照组比较，差异无统计学意义（P〉0．05），作用36h时，所有剂量组细胞存活率均降低，与对照组比较，差异有统计学意义（P〈0．05），并呈现剂量-反应和时间-反应的关系。2份受试物作用CHL细胞36h时IC50分别为21．36、23．07μg／ml。镍冶炼烟尘在25．00、50．00、100．00μg/／ml时，荧光黄（LY）由伤沿列传向邻近细胞的列数减少，与溶剂对照组比较，差异有统计学意义（P〈0．01），细胞间隙连接通讯能力降低。结论镍冶炼烟尘对体外培养的CHL细胞可产生毒性作用。抑制细胞生长。一定浓度的镍冶炼烟尘能够抑制CHL细胞的GJIC。     

甲醛、苯单独和联合致NIH/3T3细胞转化的研究

目的探讨苯、甲醛单独和联合致NIH/3T3细胞转化活性。方法采用细胞灶法观察甲醛、苯单独和联合致NIH/3T3细胞的转化作用。结果苯、甲醛及苯和甲醛联合染毒组均有细胞转化灶形成,其形成率均呈现剂量依赖关系。联合作用分析显示,苯25μg/ml 甲醛25μg/ml、苯25μg/ml 甲醛50μg/ml、苯50μg/ml 甲醛25μg/ml、苯50μg/ml 甲醛50μg/ml,两化合物联合作用转化率实测值分别为3.6%、5.8%、5.7%和7.6%。而预期转化率分别为3.5%、5.6%、5.6%、7.7%。说明在等剂量原则下,苯、甲醛单独染毒的转化细胞灶形成率之和与两化合物同时染毒的转化细胞灶形成率非常接近;析因分析表明两者间无交互作用(F=0.07,P>0.05)。结论苯、甲醛具有细胞转化活性,二者联合作用类型呈相加作用。     

苯、甲醛致中国仓鼠肺成纤维细胞DNA损伤的联合作用初步探讨

探讨苯、甲醛致体外培养细胞的中国仓鼠肺成纤维细胞DNA损伤的联合作用方式.用正交设计方案,用甲醛(0,0.319 75,0.639 5μg/ml),苯(0,0.392,0.784 mg/ml),甲醛+苯(0.319 75 μg/ml+0.392 mg/ml,0.317 95μg/ml+0.784mg/ml,0.639 5μg/ml+0.392 mg/ml.0.639 5μg/ml+0.784 mg/ml)对中国仓鼠肺成纤维细胞染毒24 h,然后通过细胞凋亡试验、单细胞凝胶电泳和DNA交联试验检测苯、甲醛致细胞DNA损伤的联合作用方式.细胞凋亡试验、单细胞凝胶电泳和DNA交联试验结果经正交实验方差分析,苯与甲醛单独或联合作用于CHL细胞,在剂量设置范围内,随剂量增加细胞凋亡率增加,细胞DNA交联率增加;苯单独作用于CHL细胞,在剂量设置范围内,随剂量增加CHL细胞DNA断裂增加,甲醛单独作用于CHL细胞,在剂量设置范围内,低剂量组细胞DNA断裂高于高剂量组,且与溶剂对照组比较,差异均有统计学意义.此外,结果显示甲醛、苯两因素具交互作用(P＜0.05).苯、甲醛均可以引起体外培养细胞的DNA损伤,而且这种损伤作用具有剂量-效应关系.当苯与甲醛共同作用于体外培养细胞时,其引起的DNA损伤作用在一定浓度范围内具有协同作用.     

丙烯腈对中国仓鼠肺细胞细胞活力和间隙连接通讯功能的影响

目的：探讨丙烯腈（ACN）对中国仓鼠肺细胞（CHL）细胞活力及细胞间隙连接通讯（GJIC）功能的影响。方法：镜下观察细胞形态学改变,采用MTT法测定细胞生长半数抑制浓度（IC50）,应用荧光染料示踪技术观测ACN对CHL细胞GJIC的影响。结果ACN染毒12和24h,细胞生长IC50分别为435．73和251．09μg/ml。低剂量组（12．5和25．0μg/ml）细胞形态与对照组相比无明显改变,较高剂量组（50．0－200．0μg/ml）细胞轻度受损（0－Ⅰ级）,高剂量组（800．0μg/ml）细胞明显受损（Ⅲ级）。ACN原形在无明显细胞毒辣性剂量（10．0－50．0μg/ml）时即可抑制GJIC,并呈持续抑制作用,存在剂量－效应和时间－0效应关系。ACN经代谢活化后,可加重对细胞GJIC的抑制作用和细胞受损程度,但在染毒12h后停止接触,该作用在一定程度上可逆转,牛磺酸作为一种重要的抗氧化剂,预处理细胞（牛磺酸剂为10和20mmol/L)可明显抑制ACN对细胞GJIC的下调作用。结论ACN在较高剂时对CHL人有毒性作用,但在无明显细胞损伤剂量时即明显抑制细胞GJIC功能,该抑作用停止接触ACN或有抗氧化剂存在可逆转,提示氧化应激在ACN所致细胞GJIC功能下调中具有重要作用。     

镍冶炼烟尘对中国仓鼠肺细胞毒性作用的实验研究

目的 观察镍冶炼烟尘对中国仓鼠肺细胞(CHL）的毒性作用。方法 以我国某镍冶炼厂电炉烟道尘为受试物,采用噻唑蓝(MTT)比色法检测CHL细胞活性。结果 不同浓度下的镍冶炼烟尘(6．25、12．50、25．00、50．00、100．00μg／ml)作用一定时间后,CHL细胞存活率下降,呈现出时间．剂量．反应关系。接触受试物36h,细胞生长半数抑制浓度IG50为21．36μg／ml。同时镜下观察细胞形态也发生改变。结论 镍冶炼烟尘可以抑制CHL细胞生长,降低线粒体代谢活性。     

不同粒径纳米Fe2O3的细胞毒性及氧化作用

目的 从细胞半数抑制浓度ICso和氧化作用的角度探讨不同粒径Fe2O3纳米粒子细胞毒性的差异。方法 将8，13和37nm3个不同尺寸的Fe2O3纳米粒子以不同剂量、时间作用于中国仓鼠肺成纤维细胞(CHL)，用活细胞计数法求得不同尺寸粒子的IC50并绘制细胞生长抑制曲线。硫代巴比妥酸法测定丙二醛(MDA)含量，黄嘌呤氧化酶法测定超氧化歧化酶(SOD)活性。结果 (1)3种尺寸的纳米粒子在一定浓度范围内，剂量与细胞抑制率呈现剂量-反应关系，而超过这一范围后，量效关系消失。(2)在量效相关的浓度范围内，3种尺寸纳米粒子的IC50分别为IC50(8nm)=279．585μg／ml，IC50(13nm)=254．739μg/ml，IC50(37nm)=561．237μg/ml。(3)Fe2O3纳米粒子可引起CHL细胞的氧化应激反应，且与作用时间有关。但MDA、SOD值变化与纳米粒子尺才、作用剂量之间无明显的量效关系。结论 不同粒径的Fe2O3纳米粒子在细胞毒性上表现出一定的差异，Fe2O3纳米粒子可引起CHL细胞的氧化应激反应，从时效性分析推论其细胞毒性与氧化性存在一定的关联。     

甲醛、三氯乙烯、三氯化铝的细胞联合毒作用

目的研究甲醛、三氯乙烯和三氯化铝的联合毒作用类型。方法噻唑蓝法(MTT)测定3种物质各自的半数生长抑制浓度(IC50)及混合物(甲醛、三氯化铝、三氯乙烯)的IC50，根据Finney数学模型和Logistic回归方法判断联合作用类型。结果甲醛、三氯乙烯、三氯化铝及其混合物质的IC50分别为0．0226，0．368，0．589和0．124mg／ml，据Finney法求得Q值为1．08，Logisitc回归模型参数艮差异无统计学意义。结论甲醛、三氯化铝、三氯乙烯(6：11：33)混合染毒，对中国仓鼠肺细胞的联合毒性表现为相加作用。     

苯、甲醛对原代大鼠肺成纤维细胞联合毒性作用的初步探讨

甲醛共同作用于原代大鼠肺成纤维细胞时,其细胞毒性为相加作用.结论 根据共毒系数法,苯、甲醛各1/2 IC50混合染毒时,苯与甲醛对原代大鼠肺成纤维细胞的联合毒性作用表现为协同作用.     

八氯二丙醚对体外培养CHL细胞DNA合成影响

目的研究八氯二丙醚对体外培养中国仓鼠肺细胞（CHL）DNA合成影响。方法采用DNA荧光定量测定方法，观察不同染毒浓度（0．250，0．187，0．125，0．062。0．046，0．031μg／m1）对CHL细胞DNA合成影响。结果八氯二丙醚浓度为0．062，0．046μg／ml时DNA合成量与对照组比差异有统计学意义，表现为合成增加（P〈0．05），浓度为0．250。0．187，0．125μg／ml时，则表现为合成抑制（P〈0．05），且呈剂量一反应关系（P〈0．05）；0．250μg／ml浓度在脱离染毒后2，4，6，12h内DNA合成量持续下降。结论在低浓度时（0．062，0．046μg/ml），八氯二丙醚可引起CHL细胞DNA合成能力增加。而在高浓度时（0．250，0．187，0．125μg／m1）则表现为DNA合成抑制，且这种抑制由DNA损伤引起。     

苯与甲醛致小鼠睾丸细胞DNA损伤联合作用

目的探讨苯与甲醛致小鼠睾丸细胞DNA联合损伤效应。方法采用单细胞凝胶电泳方法，分别检测苯染毒（剂量为50，200，800mg／kg）、甲醛染毒（剂量分别为0．3，1．2，4．8mg／kg）和苯＋甲醛复合染毒后小鼠睾丸细胞DNA损伤情况。结果在受试剂量范围内，小鼠睾丸细胞彗星率随苯或甲醛染毒剂量增加而增加（P〈0．01），其彗星尾长随苯染毒剂量增加而延长（P〈0．01），随甲醛染毒剂量增加而缩短，尤其高甲醛染毒组（P〈0．01）；复合染毒组中彗星尾长随联合染毒中苯染毒剂量增加而延长（P〈0．01），随联合染毒中甲醛染毒剂量增加而缩短（P〈0．01）。苯＋甲醛联合作用经析因素分析存在相加作用（P〈0.01）。结论苯和甲醛均能彼此增强各自所致的睾丸细胞DNA损伤效应。     

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.