甲醛与苯对小鼠遗传毒性联合作用的研究

目的探讨甲醛和苯对小鼠遗传毒性的联合作用。方法将健康昆明种小鼠随机分为阴性对照组、甲醛组、苯组、联合组、阳性对照组,进行小鼠骨髓细胞微核试验及精子畸形试验。结果苯组、甲醛组和甲醛、苯联合组小鼠骨髓细胞微核率分别为（13．5±1．27）‰、（11．9±0．99）‰、（25．5±1．58）‰及精子畸形率分别为（101．2±4．22）‰、（94．8±3．71）‰、（167．2±3．78）‰,均明显高于各自的阴性对照组（P〈0．01）。析因分析表明,甲醛和苯联合染毒致小鼠骨髓细胞微核率及精子畸形率交互作用显著（P〈0．01）。结论析因分析量效曲线随染毒剂量增大而远离,甲醛及苯联合染毒对小鼠遗传毒性有协同作用。     

甲醛和甲苯联合染毒对雄性小鼠生殖与遗传毒性作用的研究

目的研究甲醛和甲苯单独与联合吸入染毒致雄性昆明种小鼠的生殖毒性与遗传损伤作用,探讨其联合毒性效应。方法将108只雄性健康清洁级昆明种纯系小鼠随机分为9组,每组12只。分别为清洁空气对照组(0mg/m~3),低甲苯(500 mg/m~3)、高甲苯(2 000 mg/m~3)剂量组,低甲醛(1 mg/m~3)、低甲醛甲苯(1 mg/m~3+500 mg/m~3)、低甲醛高甲苯(1 mg/m~3+2 000 mg/m~3)剂量组,高甲醛(5 mg/m~3)、高甲醛低甲苯(5 mg/m~3+500 mg/m~3)、高甲醛甲苯(5 mg/m~3+2 000 mg/m~3)剂量组。采用静式吸入染毒,每天2 h,连续14 d。染毒结束次日每组取小鼠6只,进行骨髓细胞微核试验;于首次染毒后35 d,每组取小鼠6只,进行精子畸形试验。结果甲醛、甲苯单独及联合吸入染毒组雄性昆明种小鼠精子畸形率、骨髓细胞微核率均高于对照组。交互作用析因显示,甲醛吸入染毒可使雄性昆明种小鼠精子畸形率明显增高(F=139.66,P0.05),甲苯染毒也可使雄性小鼠精子畸形率明显增高(F=217.11,P0.05);甲醛染毒可使雄性小鼠骨髓细胞微核率明显增高(F=24.18,P0.05),甲苯染毒也可使雄性小鼠骨髓细胞微核率明显增高(F=76.38,P0.05);二者联合染毒所致的雄性小鼠精子畸形交互作用显著(F=6.14,P0.05),但所致的雄性小鼠骨髓细胞微核交互作用尚不明显(F=0.53,P0.05)。结论甲醛和甲苯单独与联合吸入染毒均可致小鼠精子畸形率、骨髓细胞微核率增加,联合染毒具有一定的生殖与遗传毒性协同作用。     

长期低剂量接触2,3,7,8-四氯二苯并-p-二噁英对大鼠骨髓细胞微核和精子形态的影响

目的了解长期低剂量接触2,3,7,8-四氯二苯并-p-二噁英(TCDD)对雄性SD大鼠骨髓细胞微核和精子形态的影响。方法将1月龄SD大鼠随机分为4组,分别为阴性对照组(给予玉米油)和3个TCDD染毒组(日染毒剂量为2、10、50ng/kg)。13周后,另设微核阳性对照组(环磷酰胺,日染毒剂量为60mg/kg,连续3d)观察骨髓嗜多染红细胞微核率和精子畸形率。结果长期低剂量接触TCDD导致大鼠骨髓细胞微核率增加,精子畸形率增高。阴性对照组、2、10、50ng/kg染毒组、阳性对照组微核率分别为9.0‰,13.0‰,21.2‰,24.4‰和87.4‰,10、50ng/kg组微核率均高于阴性对照组(均P0.01);对照组、2、10、50ng/kg组精子畸形率分别为10.4‰,35.0‰,49.8‰,47.0‰,各染毒组畸形率均高于对照组(均P0.01),畸形以颈折叠为主。结论长期低剂量接触TCDD对哺乳动物体细胞和雄性生殖细胞具有致突变性,且生殖细胞对TCDD的毒性更敏感。     

茶树菇水煎液对环磷酰胺诱发小鼠基因突变的保护作用

目的 研究茶树菇水煎液对环磷酰胺诱发KM小鼠突变的保护作用.方法 用改进的小鼠骨髓细胞微核实验和小鼠精子畸形实验方法,研究茶树菇水煎液对环磷酰胺诱发小鼠骨髓细胞微核和精子畸形的保护作用.结果 给40 mg/kg环磷酰胺后,茶树菇水煎液低、中、高剂量组及阳性对照组的微核率、精子畸形率均比阴性对照组显著升高(P＜0.01),茶树菇水煎液高剂量组的微核率18.2‰,显著低于阳性对照组微核率25.8‰(P＜0.01),茶树菇水煎液高剂量组的精子畸形率58.7‰,显著低于阳性对照组精子畸形率76.5‰(P ＜0.01).结论 茶树菇水煎液对环磷酰胺诱发小鼠骨髓细胞微核和精子畸形有保护作用.     

甲醛与苯对动物细胞的遗传学效应及联合毒性研究

目的探讨不同浓度的甲醛与苯对小鼠外周血红细胞、骨髓细胞微核的诱发效应。方法甲醛、苯及两者联合作用分高、中、低三个剂量组，采用静吸式染毒方法，每天2h，连续染毒15d，考查微核率的变化。结果染毒后小鼠外周血红细胞、骨髓PCE细胞微核率均明显升高，与对照组相比差异显著。结论甲醛和苯均可不同程度的影响小鼠外周血红细胞和骨髓细胞的微核细胞率，并呈现剂量效应关系，联合作用时效应最强。     

4种常见残留农药联合作用对小鼠遗传毒性研究

目的利用小鼠骨髓嗜多染红细胞微核试验及小鼠精子畸形试验,研究马拉硫磷、毒死蜱、氯氰菊酯和高效氯氟氰菊酯4种常见残留农药在每日允许摄入剂量下单独与联合作用对小鼠遗传毒性的影响。方法将70只昆明种小鼠随机分为7组,每组10只,雌雄各半,分别为溶剂对照组,阳性对照组,马拉硫磷(0.3 mg/kg·BW)组,毒死蜱(0.01 mg/kg·BW)组,氯氰菊酯(0.02 mg/kg·BW)组,高效氯氟氰菊酯(0.02 mg/kg·BW)组及农药联合作用组。每天经口染毒1次,连续4天,于染毒结束次日进行小鼠骨髓嗜多染红细胞微核试验;同时,将35只雄性昆明种小鼠随机分为7组,每组5只,组别同上,每天经口染毒1次,连续5天,于首次染毒后第35天进行小鼠精子畸形试验。结果 4种农药单独作用时,小鼠骨髓细胞微核率及精子畸形率略高于溶剂对照组,差异无统计学意义(P0.05);4种农药联合作用时,小鼠骨髓细胞微核率及精子畸形率升高,分别为17.30±2.83及5.84±1.05,显著高于单独作用组及溶剂对照组,差异有统计学意义(P0.05)。结论马拉硫磷、毒死蜱、氯氰菊酯、高效氯氟氰菊酯单独与联合经口染毒均可致小鼠骨髓细胞微核率、精子畸形率增加,且联合染毒对小鼠的遗传损伤具有一定的相加作用,具有引起遗传毒性的风险。     

吸入甲醛对小鼠精子畸形率和骨髓细胞微核率的影响

[目的]探讨吸入甲醛对小鼠生殖细胞和体细胞的遗传毒性作用。[方法]用不同剂量（5．18g／m^3、2．59g／m^3、1．29g／m^3）的甲醛静式吸入染毒小鼠5d和4d，均于末次染毒24h后颈椎脱臼处死小鼠，观察甲醛对小鼠精子畸形率和骨髓细胞微核率的影响。[结果]高剂量组的精子畸形率为3．88％，微核率为8．63‰，均超过正常值，且与阴性对照组比较差异均有统计学意义（P〈0．05）。[结论]吸入一定浓度的甲醛对小鼠生殖细胞和体细胞具有致遗传毒性作用。     

氯乙烯诱变性研究

目的近一步研究不同剂量下氯乙烯对哺乳动物的致突变作用及生殖毒性.方法通过小鼠静式吸入染毒法进行精子畸变试验和微核试验的方法,观察氯乙烯的致微核率和精子畸变率.结果试验动物经氯乙烯染毒后,精子畸变试验中高、中、低染毒组畸变率分别为4.12%、2.88%、2.32%,与阴性对照组畸变率1.46%相比差异均有非常显著性(P＜0.01);微核试验高、中、低剂量组微核率分别为13.1‰、9.5‰、8.4‰,与阴性对照组微核率3.3‰相比差异亦均有非常显著性.结论氯乙烯可能具有诱变作用.     

预防型抗氟剂(I型-1)急性毒性和致突变性研究

目的探讨预防型抗氟剂(I型-1)的急性毒性和致突变效应.方法小鼠灌胃,计算LD50;小鼠骨髓细胞微核试验;小鼠精子畸形试验.结果预防型抗氟剂(I型-1)LD50为1 814mg/kg;染毒组PCE微核率与阴性对照组无显著差别;高剂量组精子畸形率显著高于阴性对照组.结论预防型抗氟剂(I型-1)属低毒类物质,对小鼠骨髓细胞染色体无损伤效应,高剂量对生殖细胞可能产生影响.     

低浓度苯对小鼠过氧化损伤及致突变作用

目的探讨低浓度苯对小鼠过氧化损伤及致突变作用。方法将60只雄性昆明种小鼠随机分为高、中、低3个浓度组和1个对照组。采用动式吸入染毒,3个浓度组的苯染毒浓度分别为(48.7±10.6),(10.4±5.9),(3.9±2.1)mg/m3,每周5d,连续3个月。检测血常规、血清中丙二醛(MDA)含量、超氧化物歧化酶(SOD)及谷胱甘肽过氧化物酶(GSH-Px)活力、骨髓微核率和精子畸形率。结果随着染毒浓度的增加,白细胞计数、血小板计数和血红蛋白含量逐渐下降,并呈剂量-反应关系。高、中浓度组小鼠血清SOD活力分别为[(79.76±11.16)、(85.94±9.36)NU/ml],均明显低于对照组(102.62±22.25)NU/ml,差异有显著性(P<0.05)。高浓度组小鼠血清MDA含量[(13.09±2.67)nmol/ml]高于对照组[(10.33±1.63)nmol/ml],GSH-Px活力[(113.64±20.54)U]低于对照组[(135.25±20.85)U],差异有显著性(P<0.05)。与对照组小鼠骨髓微核率2.60‰比较,中、高浓度组小鼠骨髓微核率(4.50‰,6.70‰)明显升高,差异有显著性(P<0.05)。但各浓度组与对照组比较,精子畸形率的差异无显著性。结论低浓度苯可引起小鼠造血系统损伤、过氧化损伤及致突变作用。     

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.