邻苯二甲酸(2-乙基己基)酯对雄性小鼠的生殖毒性

为探讨邻苯二甲酸(2-乙基己基)酯[di(2-ethylhexyl)phthalate,DEHP]对小鼠的生殖毒性.将30只成年健康SPF级雄性昆明小鼠随机分成5组,分别为阴性对照(玉米油)组和低(1 250 mg/kg)、中(2 500 mg/kg)、高剂量(5000mg/kg)DEHP染毒组以及阳性对照(环磷酰胺40 mg/kg)组,每组6只.除阳性对照组采用腹腔染毒外,其余各组采用经口灌胃方式进行染毒,染毒容量为0.02 ml/g,每天1次,连续染毒5d.于首次染毒5周后,采用一般生殖毒性实验方法对精子计数和精子存活率、畸形率、活动率进行测定.结果显示,与阴性对照组比较,各剂量DEHP染毒组小鼠精子计数和精子存活率均较低;而中、高剂量DEHP染毒组精子畸形率较高,活动率较低,差异均有统计学意义(P＜0.05).随着DEHP染毒剂量的升高,小鼠精子计数和活动率、精子存活率均呈下降趋势,精子畸形率呈上升趋势.提示DEHP对雄性小鼠具有一定的生殖毒性.     

DEHP亚慢性暴露对大鼠精子运动参数影响

目的观察邻苯二甲酸(2-乙基已基)酯(DEHP)染毒90 d对大鼠精子运动能力的毒性作用。方法将健康清洁级SD雄性大鼠40只随机分为对照组和3个DEHP染毒组(5、50、500 mg/kg),进行90 d经口染毒;取睾丸、附睾称重,并用扩散法收集大鼠附睾尾精子,应用计算机辅助精子分析系统(CASA)对精子的运动参数进行检测。结果 5 mg/kg DEHP组大鼠精子直线性(LIN)为(44.00±2.52)%,明显低于对照组(50.00±2.71)%(P0.05);500 mg/kg DEHP组大鼠精子鞭打频率(BCF)为(5.8±4.2)Hz,明显低于对照组(10.4±1.7)Hz(P0.05);与对照组比较,500 mg/kg DEHP组大鼠精子的平均路径速度(VAP)、直线运动速度(VSL)、曲线运动速度(VCL)、精子头侧摆幅度(ALH)、BCF明显下降,差异均有统计学意义(均P0.05);随着DEHP染毒浓度增加,大鼠精子各项运动参数逐渐降低,精子的运动能力下降。结论 DEHP对大鼠附睾精子的运动能力有直接毒性作用。     

邻苯二甲酸(2-乙基己基)酯低剂量暴露对雄性小鼠生殖发育的影响

目的观察邻苯二甲酸(2-乙基己基)酯(DEHP)低剂量暴露对雄性小鼠的生殖发育毒性作用。方法将清洁级ICR小鼠随机分为4个DEHP染毒组(1/120LD50,1/60LD50,1/30LD50,1/15LD50,即250、500、1000、2000mg/kg组),阳性对照组(环磷酰胺,40mg/kg)和阴性对照组(玉米油);DEHP染毒组和阴性对照组灌胃染毒30d,阳性对照组灌胃5d,每天1次。采用一般生殖毒性试验和显性致死突变试验的方法,研究DEHP低剂量暴露对雄性小鼠生殖细胞的损伤作用和生育能力的影响。结果一般生殖毒性试验结果显示,低剂量DEHP染毒雄性小鼠睾丸、附睾重量降低(r睾丸=-0.578,P<0.01;r附睾=-0.661,P<0.01),精子总数减少(r=-0.608,P<0.01),精子畸形率增高(r=0.836,P<0.01),精子活动度降低(P<0.05)。显性致死突变试验研究结果显示,250mg/kgDEHP染毒组小鼠受孕率降低,但与阴性对照组比较,差异无统计学意义(P>0.05);DEHP染毒组子代小鼠平均着床数减少(r=-0.892,P<0.01),与阴性对照组比较,差异均具有统计学意义(P<0.01);平均早期死亡胚胎数随染毒剂量增加而增加(r=0.996,P<0.01),250mg/kg染毒组与阴性对照组比较,差异无统计学意义(P>0.05)。结论DEHP低剂量暴露对雄性小鼠具有生殖毒性作用,可降低小鼠受孕率,使子代小鼠平均着床数减少,平均早期死亡胚胎数增加。     

邻苯二甲酸二甲酯对雄性小鼠生殖系统的影响

目的探讨邻苯二甲酸二甲酯(DMP)的生殖毒性作用。方法以成年雄性ICR小鼠为研究对象,设1 000 mg/kg、500 mg/kg、250 mg/kg剂量和对照组连续染毒2个月。测定脏器系数、精子运动及精子数、睾丸细胞酶活力及部分血清生化指标。结果 DMP能引起雄鼠500 mg/kg和1 000 mg/kg染毒组睾丸重量减少(P0.01),各染毒组附睾重量均减少(P0.01),500 mg/kg和1 000 mg/kg染毒组肝脏肿大(P0.01); 1 000 mg/kg染毒组Ⅰ级、Ⅳ级运动精子、精子数与对照组比较差异有统计学意义(P0.01);各染毒组AKP活力比对照组均显著降低(P0.01);各染毒组血清Cr、1 000 mg/kg染毒组UREA都显著升高,与对照组比较差异有统计学意义(P0.01)。结论 DMP对雄性小鼠具有一定生殖毒性作用,睾丸细胞酶活力的改变,可能与DMP导致睾丸的支持细胞和生精上皮细胞损伤作用有关。     

不同粒径纳米和微米二氧化硅对雄性大鼠生殖毒性的实验研究

目的探讨不同粒径纳米二氧化硅与微米二氧化硅对雄性大鼠的生殖毒性效应。方法将104只健康SPF级雄性SD大鼠随机分为13组,分别为对照(生理盐水)组和低(1.5 mg/kg)、中(4.5 mg/kg)、高剂量(13.5 mg/kg)20、60、100 nm纳米二氧化硅及微米二氧化硅染毒组,每组8只。采用非暴露气管插管直接滴注法进行染毒,隔日染毒1次,共染毒6周。检测大鼠睾丸内睾酮(T)含量及附睾精子数量、精子存活率和精子畸形率。结果与对照组比较,各剂量20、60 nm纳米二氧化硅染毒组及4.5、13.5 mg/kg的100 nm纳米二氧化硅染毒组大鼠T分泌量均降低(P0.05),13.5 mg/kg的20 nm纳米二氧化硅染毒组大鼠T分泌量低于相同浓度的100 nm纳米二氧化硅染毒组(P0.05),各剂量微米二氧化硅染毒大鼠睾丸T分泌量无明显变化(P0.05);4.5、13.5 mg/kg的20 nm纳米二氧化硅染毒组和13.5 mg/kg的60、100 nm纳米二氧化硅及13.5 mg/kg的微米二氧化硅染毒组大鼠的精子数、精子存活率均降低(P0.05),4.5、13.5 mg/kg的20、60、100 nm纳米二氧化硅染毒组大鼠的精子畸形率升高(P0.05),各剂量微米二氧化硅染毒大鼠精子畸形率无明显变化(P0.05)。结论纳米二氧化硅及微米二氧化硅均对雄性大鼠具有生殖毒性,且纳米二氧化硅的生殖毒性效应明显强于微米二氧化硅;纳米二氧化硅的粒径越小,生殖毒性效应愈强。     

邻苯二甲酸二(2-乙基己基)酯、氯氰菊酯单独及联合染毒对青春前期雄性大鼠生殖发育的不良影响

目的探讨邻苯二甲酸二(2-乙基己基)酯(DEHP)和氯氰菊酯(CYP)单独及联合染毒对青春前期雄性大鼠生殖发育的不良影响。方法选择SPF级3周龄雄性SD大鼠24只,随机分为4组,分别为对照组(喂饲玉米油)、DEHP染毒组(500mg/kg)、CYP染毒组(80mg/kg);DEHP、CYP联合染毒组(DEHP 500mg/kg+CYP 80mg/kg),每组6只。采用经口灌胃方式染毒,每天1次,连续染毒30天。于末次染毒24小时后处死动物,测定大鼠体重、睾丸湿重,并计算睾丸系数;测定血清睾酮水平;制备睾丸病理组织切片,光镜观察其组织学改变,电镜观察生殖细胞超微结构;测定睾丸标志酶乳酸脱氢酶(LDH)、酸性磷酸酶(ACP)、碱性磷酸酶(ALP)和琥珀酸脱氢酶(SDH)的活性。结果与对照组相比,DEHP、CYP单独及联合染毒组睾丸下降时间和包皮分离时间明显延迟,肛门生殖器间距明显缩短(P<0.05或0.01);DEHP单独染毒组睾丸重量及睾丸系数明显降低,血清睾酮水平显著下降(P<0.05),睾丸匀浆中ALP、ACP和LDH活性明显增高,SDH活性显著下降(P<0.01);DEHP、CYP单独及联合染毒组睾丸病理组织学、生殖细胞超微结构均可见明显异常。结论 DEHP、CYP单独及联合染毒对青春前期雄性大鼠均具有明显的生殖毒性作用,可引起生精细胞、支持细胞和间质细胞的变性、坏死及功能障碍,从而导致雄性生殖系统发育和功能的显著异常。其中,DEHP单独染毒呈现主效应,DEHP、CYP联合染毒对大鼠的生殖毒性未呈现明显交互影响。     

孕期及哺乳期邻苯二甲酸二(2-乙基己基)酯经口染毒对雄性仔鼠生殖发育的影响

目的观察邻苯二甲酸二(2-乙基已基)酯(DEHP)对雄性仔鼠的生殖发育毒性作用。方法采用围生期毒性试验的研究方法,将清洁级SD大鼠随机分为阴性对照组(玉米油)和4个DEHP染毒组(125、250、500、1000mg/kg),采用宫内及哺乳期[受孕后第2天～仔鼠出生后第21天(PND21)]经口灌胃的方式染毒。记录比较雄性仔鼠肛殖距、不同发育阶段雄性仔鼠体重、睾丸、附睾重量、仔鼠出生后第50天(PND50)附睾尾精子总数、精子活率及精子畸形数。结果 125～500mg/kg组不同发育阶段仔鼠体重随染毒剂量增加而增加,500mg/kg组PND21体重与对照组比较,差异有统计学意义(P0.01),1000mg/kg组体重均低于同发育阶段对照组,PND21体重与对照组比较,差异具有统计学意义(P0.05)。1000mg/kg组不同发育阶段仔鼠睾丸重量明显降低,与对照组比较,差异有统计学意义(P0.01),附睾重量与对照组比较差异均无统计学意义(P0.05)。仔鼠出生后4天肛殖距不同程度缩短,除125mg/kg组外,其余各剂量组与对照组比较,差异均有统计学意义(P0.01)。PND50雄性仔鼠精子总数、精子活率均不同程度降低,精子畸形率不同程度增高,1000mg/kg组与对照组比较,差异有统计学意义(P0.05)。结论母鼠孕期及哺乳期暴露DEHP可影响雄性仔鼠生长、生殖发育。     

妊娠期邻苯二甲酸(2-乙基己基)酯暴露对成年后子代雄鼠精子的致突变作用

目的探讨妊娠期邻苯二甲酸(2-乙基己基)酯(DEHP)暴露对成年后子代大鼠精子的致突变作用。方法将32只健康SPF级SD孕鼠随机分为4组,分别为对照(玉米油)组和2、10、50 mg/kg DEHP染毒组,每组8只。自GD13至GD19,采用灌胃方式进行,每天1次。每窝随机选取1只初生雄性仔鼠,观察其生殖器的发育情况;于70日龄时,观察精子的畸形情况。结果妊娠期DEHP暴露雄性仔鼠的体重、肛殖距系数(AGI)及主要生殖器(睾丸、附睾、精囊腺)的脏器系数与对照组比较,差异无统计学意义(P0.05);主要生殖器未见畸形。2 mg/kg及50 mg/kg DEHP染毒组子代雄性大鼠精子的头部畸形率和总畸形率均高于对照组,差异有统计学意义(P0.05);而各剂量DEHP染毒组子代雄性大鼠的尾部畸形率与对照组比较,差异均无统计学意义(P0.05)。结论在本实验条件下,妊娠期较低(2 mg/kg)及较高(50 mg/kg)剂量DEHP暴露对子代雄鼠的精子均具有遗传毒性作用。     

邻苯二甲酸二(2-乙基)己酯对大鼠的亚慢性毒性研究

为研究邻苯二甲酸二(2-乙基)己酯(di-2-ethylhexyl phthalate,DEHP)对大鼠的亚慢性毒性作用,将48只健康的SPF级SD大鼠按体重随机分为4组,分别为对照(玉米油)组和50.0、158.2、500.0 mg/kg DEHP染毒组,每组12只,雌雄各半。采用灌胃方式进行染毒,连续染毒13周。检测中期(染毒第7周)及终期血常规、终期生化指标和血清甲状腺激素水平。结果显示,与对照组比较,500.0 mg/kg DEHP染毒组雄性大鼠的中期红细胞数及血清中T3的浓度均较低;158.2、500.0 mg/kg DEHP染毒组雄性大鼠的终期红细胞数、甘油三酯水平、血清中T4的浓度均较低,差异均有统计学意义(P0.05)。且随着DEHP染毒浓度的升高,大鼠血清中T3、T4的浓度均呈下降趋势。提示DEHP对大鼠的肝、肾、睾丸及甲状腺等多器官具有毒性作用。     

3,4-二氯苯胺短期重复染毒对雄性大鼠精子的影响

目的研究3,4-二氯苯胺(3,4-DCA)对雄性大鼠精子的影响,以探讨3,4-DCA对雄性大鼠的生殖毒性作用。方法将40只健康成年SPF级Wistar雄性大鼠按体重随机分为39、81、170、357 mg/kg 3,4-DCA染毒组和溶剂对照组(玉米油),每组8只,经口灌胃染毒,灌胃容积为5 ml/kg,1次/d,连续染毒35 d。染毒结束后,处死大鼠,取附睾制成精子悬液,测定精子密度;台盼蓝染色测定精子的存活率,观察精子的活动能力并分级,计算精子活动率;测定精子的畸形率。结果与对照组比较,39 mg/kg 3,4-DCA染毒组体重略有增加,但差异无统计学意义(P>0.05);与对照组比较,170、357 mg/kg 3,4-DCA染毒组体重降低,差异均有统计学意义(P<0.01)。各组大鼠睾丸系数和附睾系数比较,差异无统计学意义(P>0.05)。与对照组比较,170和357 mg/kg 3,4-DCA染毒组精子密度降低,81、170、357 mg/kg 3,4-DCA染毒组精子存活率和精子活动率降低,39、81、170和357 mg/kg 3,4-DCA染毒组精子畸形率升高,差异均有统计学意义(P<0.05...     

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.     

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.     

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.