温室土壤有机提取物遗传毒性研究

[目的]检测温室土壤中有机提取物的遗传毒性作用. [方法]以小鼠为实验动物,共分5组:阴性对照组(二甲亚砜)、阳性对照组(环磷酰胺)及土壤有机提取物低、中、高剂量组,染毒剂量分别为5、15和30g土壤干重/(kg小鼠体重·d),染毒方式为每日灌胃1次,连续染毒4周.用胞质分裂阻滞微核细胞试验和彗星试验分别检测有机提取物所致小鼠外周血淋巴细胞的染色体损伤作用和外周血细胞的DNA损伤作用. [结果]有机提取物剂量与微核率具有较明显的剂量-效应关系,显著高于阴性对照组;随着有机提取物作用剂量的增加,彗星尾长、尾部DNA含量和Olive尾矩显著升高. [结论]温室土壤中有机提取物可以诱使小鼠发生染色体和DNA损伤.     

地表水中有机提取物对人B淋巴细胞DNA的损伤效应

目的探究地表水中有机提取物对人B淋巴细胞DNA的损伤效应。方法于2010年6—8月,采集某江流域18个采样点水样并提取有机物。将处于对数生长期的人B淋巴母细胞悬液分别暴露于0(对照)、250、500、1 000 ml/ml水样有机提取物培养24 h;采用CCK-8活细胞计数试剂盒和彗星试验分别研究水样有机提取物对细胞存活率的影响及其DNA损伤效应,并检测细胞内活性氧自由基(ROS)含量的变化,以评价水样有机提取物的氧化损伤效应。结果与对照组比较,除250 ml/ml采样点5、11、12水样外,各采样点水样有机提取物在各暴露剂量下对人B淋巴母细胞的存活率均较低,差异有统计学意义(P0.01);且随着各采样点水样有机提取物暴露剂量的升高,人B淋巴细胞的存活率呈下降趋势。与对照组相比,采样点4、5、6水样有机提取物在250、500、1 000 ml/ml剂量下对人B淋巴母细胞彗星尾部DNA含量无明显影响,采样点9、11、12和15水样有机提取物仅在1 000 ml/ml剂量下导致人B淋巴母细胞尾部DNA含量增加,差异有统计学意义(P0.05,P0.01);其余各采样点水样有机提取物在500、1 000 ml/ml剂量下均可导致人B淋巴母细胞彗星尾部DNA含量增加,差异有统计学意义(P0.05,P0.01)。与对照组相比,采样点16水样有机提取物在500 ml/ml剂量下对人B淋巴细胞内ROS含量无显著影响(P0.05),其余各采样点水样有机提取物在250~1 000 ml/ml剂量范围内均可显著诱导人B淋巴细胞内ROS的产生,差异有统计学意义(P0.01);除采样点15外,随着各采样点水样有机提取物暴露剂量的升高,人B淋巴细胞中ROS的含量均呈上升趋势。结论该流域江水中有机提取物对人B淋巴细胞DNA有显著的损伤效应,可能与细胞内ROS含量增加有关。     

彗星试验检测甲氨喋呤诱发人淋巴细胞DNA的损伤

目的用彗星试验评价人外周血淋巴细胞暴露于不同剂量甲氨喋呤（MTX）后的DNA损伤。方法外周血来自男女两名助血员,淋巴细胞分离后用终浓度为0（溶剂对照）、0、5、10、25、50、100ug ml^-1的MTX分别染毒6h和24h,而后用彗星试验检测各组淋巴细胞的DNA损伤,以尾长（TL）和尾相（TM）作为DNA损伤的指标,并分析剂量-效应关系。结果染毒组DNA损伤明显高于对照组,并有剂量-效应关系。结论彗星试验是一种快速、简便测定DNA损伤的方法。MTX对体外培养的人淋巴细胞具有DNA损伤效应。     

低剂量辐射联合环磷酰胺对荷瘤鼠DNA损伤的影响

目的研究低剂量辐射联合环磷酰胺对荷瘤鼠外周血淋巴细胞DNA损伤的影响。方法荷瘤鼠随机分为对照组、CTX化疗组(CTX组,40mg/kg)和低剂量照射联合CTX组(LDR CTX组),环磷酰胺给予前6h行5cGy的低剂量照射,连续3 d。采用中性单细胞凝胶电泳检测低剂量辐射联合化疗后对荷瘤鼠外周血淋巴细胞DNA双链断裂的情况。观察了尾长、彗星长、头DNA%、尾DNA%、尾矩、Olive尾矩等指标的变化。结果LDR CTX组其尾长、彗星长、头DNA%、尾DNA%、尾矩、Olive尾矩均比CTX组明显减小,各项指标差异均有显著性(P<0.05)。结论荷瘤鼠预先接受低剂量全身照射能减轻环磷酰胺治疗后外周血淋巴细胞DNA损伤。     

大气细颗粒物污染监测及其遗传毒性研究

目的比较燃煤污染型城市(太原市)和燃煤与汽车尾气混合污染型城市(北京市)细颗粒物(PM2.5)污染水平并研究其遗传毒性。方法采用滤膜法采集太原市和北京市大气中细颗粒物,并用单细胞凝胶电泳法,以人肺泡上皮细胞(A549)作为靶细胞,测定细颗粒物对细胞DNA的损伤。结果北京市冬季大气中PM2.5为0.028～0.436mg/m3,太原市为0.132～0.681mg/m3。细颗粒物在5、50、200μg/ml浓度内染毒12h和24h均可引起人肺泡上皮细胞DNA损伤,与阴性对照组相比,其拖尾率和尾长差异均有显著性(P<0.05),且存在剂量-反应关系。结论细颗粒物具有一定程度的遗传毒性。     

1,2-二氯乙烷致小鼠血淋巴细胞遗传毒性研究

目的研究1,2-二氯乙烷(1,2-DCE)对小鼠血淋巴细胞DNA和骨髓细胞染色体的损伤作用,探讨1,2-二氯乙烷的遗传毒性。方法采用单细胞凝胶电泳和微核试验方法,分别检测1,2-DCE不同染毒剂量(50,100,200,400 mg/kg)小鼠外周血淋巴细胞DNA和骨髓细胞染色体损伤情况。结果除50 mg/kg剂量组外,小鼠血淋巴细胞的彗星细胞率及尾长、骨髓细胞微核率随1,2-DCE染毒剂量的增加而增加(P<0.01)。其中,400 mg/kg剂量组彗星细胞率、平均尾长、微核率分别为45.5%,(37.24±3.17)μm,12.0‰,显著高于阴性对照组和50 mg/kg剂量组(P<0.01)。染毒剂量与彗星细胞率、平均尾长、微核率之间存在着剂量-反应关系(R彗星率=0.980 2,R彗尾长=0.976 6,R微核率=0.975 1,P<0.01)。结论1,2-DCE可导致小鼠血淋巴细胞DNA损伤和骨髓细胞染色体异常。表明1,2-DCE具有细胞遗传毒性。     

彗星实验检测吸毒人群淋巴细胞DNA

目的应用彗星实验方法对吸毒人群淋巴细胞DNA损伤情况进行检测。方法在湖北省某市戒毒所随机抽取123名吸毒人员作为暴露组,同时选择79名非吸毒者作为对照组,进行彗星实验。结果暴露组和对照组的彗星细胞拖尾率分别为10.03%和1.26%,差异有统计学意义;两组的彗星细胞拖尾的尾长分别为(2.35±0.88)和(2.05±0.76)μm,差异有统计学意义;吸毒年限长者彗星细胞拖尾率(11.49%)显著高于吸毒年限短者(2.98%)。多因素非条件Logistic回归分析结果表明,吸毒人群DNA损伤的可能性明显高于对照组。结论吸毒对人体淋巴细胞DNA有一定损伤,吸毒时间越长,DNA损伤越严重。     

低强度2 450 MHz微波对丝裂霉素C遗传毒性作用影响的体外实验

目的研究低强度2 450 MHz微波是否增强丝裂霉素C(MMC)对人外周血淋巴细胞的遗传毒性.方法采用彗星试验和胞质分裂阻断微核试验(CBMN),在体外检测2 450 MHz微波(5.0mW/cm2)与MMC诱发的DNA单链断裂及染色体损伤的情况.结果微波辐射组外周血淋巴细胞的彗星长度[男、女分别为(29.1±8.1)、(25.9±7.5)μm]与对照组[男、女分别为(26.3±6.6)、(24.1±4.3)μm]比较,差异无显著性(P＞0.05);MMC各剂量组(0.012 5、0.025 0、0.050 0、0.100 0μg/ml)的彗星长度均长于对照组,差异有显著性(P＜0.01),而且随着MMC剂量的增加,彗星长度增长;微波联合MMC(MW+MMC)各剂量组的彗星长度也随着MMC剂量增加而增长,且明显长于对照组,差异亦有显著性(P＜0.01),当MMC≥0.025 0μg/ml时,微波与MMC可协同增加DNA单链断裂.微核试验结果表明,微波组的微核率与对照组的差异无显著性(P＞0.05).MMC组和MW+MMC组在MMC≥0.050 0μg/ml时,其微核率与对照组比较,差异有显著性(P＜0.05或P＜0.01).MW+MMC组的微核率高于相应的MMC组,但差异无显著性(P＞0.05).结论低强度2450 MHz微波辐射未能诱发人外周血淋巴细胞DNA和染色体损伤,但彗星试验显示,其可增强MMC诱发的DNA单链断裂效应.     

用彗星试验研究低剂量辐射对荷瘤鼠放疗后DNA损伤的影响

目的　研究低剂量辐射对荷瘤鼠放疗后外周血淋巴细胞DNA损伤的影响。方法　采用中性单细胞凝胶电泳检测低剂量辐射对荷瘤鼠放疗后外周血淋巴细胞DNA双链断裂的情况。观察了尾长、彗星长、头DNA%、尾DNA%、尾矩、Olive尾矩等指标的变化。结果　2.0 Gy局部放疗前 6 h接受 5 cGy低剂量全身照射并连续 5d组, 其尾长、尾DNA%、尾矩、Olive尾矩均较单纯局部放疗组明显减小, 各项指标差异均有显著性(P<0.01)。结论　局部放疗前荷瘤鼠预先接受低剂量全身照射能减轻荷瘤鼠放疗后外周血淋巴细胞DNA损伤。     

污水处理传统工艺与新工艺出水中有机提取物的遗传毒性研究

目的评价污水处理厂传统处理工艺和新技术处理工艺出水中有机提取物的遗传毒性,比较两种处理工艺对微量有机污染物的去除效果。方法采用树脂吸附固相萃取富集水样中的微量有机污染物,利用蚕豆根尖微核试验和人外周血淋巴细胞单细胞凝胶电泳试验检测水样中有机提取物的遗传毒性大小。结果在原水样中微量有机污染物浓缩100倍条件下,蚕豆根尖细胞微核率在各组间的差异具有显著性(F=42.526,P0.001),DMSO组和新技术出水组与阴性对照组的差异不具有显著性(P!0.05),而与新技术出水组相比,二级出水和进水与其的差异具有显著性,二级出水和进水组之间差异也存在显著性(P0.05);各水样染毒人外周血淋巴细胞产生彗星的尾长和拖尾率在各组间均有差异(F值分别为243.535和148.623,P0.001),进水、二级出水染毒人外周血淋巴细胞产生彗星的尾长和拖尾率均高于阴性对照组(P0.01),二级出水、三级出水染毒人外周血淋巴细胞产生彗星的尾长和拖尾率均低于进水(P0.01),三级出水产生彗星的拖尾率低于二级出水(P0.01)。结论污水经处理后遗传毒性显著下降,但仍对环境具有潜在的危害;新技术对污水中微量有机污染物的去除效果明显好于传统技术。     

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.     

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.     

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.