氯乙酸甲酯染毒对大鼠精子DNA损伤的研究

目的 应用精子单细胞凝胶电泳方法探讨氯乙酸甲酯对雄性大鼠精子DNA的损伤.方法 将55只雄性大鼠按体重随机分成5组,4个剂量组分别给予4.3、8.6、17.2和34.4 mg/kg的氯乙酸甲酯,对照组给予生理氯化钠连续经口灌胃13周处死,取附睾精子进行单细胞凝胶电泳试验.结果 高剂量染毒组精子细胞拖尾率和尾长[17.4%,(5.80±6.56)μm]与对照组[5.5%,(2.70±1.76)μm]之间差异有显著性(P＜0.05).结论 高剂量氯乙酸甲酯对雄性大鼠精子DNA有损伤作用.     

稀土氟化钕对雄性大鼠睾丸毒性的影响

目的探讨稀土氟化钕(Nd F3)对雄性大鼠睾丸的影响。方法将48只SPF级健康成年雄性SD大鼠随机分为对照组和低、中、高剂量Nd F3染毒组,每组12只,采用非暴露式气管注入法建立大鼠损伤模型。3个染毒组分别灌注不同剂量的Nd F3溶液,染毒剂量分别为70、210、280 mg/kg,对照组予以相应体积的生理盐水,初次染毒间隔15 d后再次染毒,于第42天称重后处死。检测大鼠血清睾酮含量及附睾精子数量、精子存活率、精子畸形率。采用电感耦合等离子体质谱法测定大鼠睾丸组织Nd F3水平,在普通光镜下观察大鼠组织病理学改变,采用TUNEL法进行睾丸细胞凋亡检测,用透射电子显微镜进行睾丸组织超微结构检测。结果与对照组比较,各染毒组大鼠睾丸内Nd F3含量均增加,差异有统计学意义(P0.05);与对照组相比,低、高剂量组大鼠血清睾酮含量升高,中剂量组睾酮含量下降,且高剂量组睾酮含量低于低剂量组、高于中剂量组,差异均有统计学意义(P0.05)。与对照组相比,中、高剂量组大鼠精子数量、精子存活率降低,精子畸形率、睾丸细胞凋亡指数升高,差异有统计学意义(P0.05)。结论低剂量Nd F3颗粒物可促进大鼠睾丸发育,但中剂量Nd F3可损伤睾丸组织,进而可能影响雄性大鼠生殖功能。     

姜黄素对砷致大鼠睾丸生精细胞凋亡的拮抗作用

目的研究姜黄素对砷致大鼠睾丸生殖细胞凋亡的拮抗作用。方法将50只健康清洁级Wistar雄性大鼠随机分为5组,分别为对照(双蒸水)组和亚砷酸钠(100 mg/L)染毒组及低、中、高剂量姜黄素(100 mg/L亚砷酸钠+25、50、100mg/kg姜黄素)干预组,每组10只。亚砷酸钠采用自由饮用方式进行染毒;姜黄素采用经口灌胃方式染毒,每周3次,连续8周。测量生精小管平均直径;测定大鼠血清睾酮浓度及睾丸生精细胞凋亡指数。结果与对照组比较,亚砷酸钠染毒组大鼠血清睾酮的水平降低,生精小管直径缩小,而睾丸生精细胞凋亡指数升高,差异有统计学意义(P0.01)。与亚砷酸钠染毒组比较,中、高剂量姜黄素干预组大鼠血清睾酮的水平升高,生精小管直径增大,而睾丸生精细胞凋亡指数下降,差异均有统计学意义(P0.05)。且随着姜黄素染毒剂量的升高,大鼠血清睾酮水平和生精小管直径均呈上升趋势,而睾丸生精细胞凋亡指数呈下降趋势。结论姜黄素对砷致大鼠睾丸生殖细胞凋亡具有拮抗作用。     

氟对雄性大鼠生精细胞Fas蛋白表达影响的研究

目的探讨氟对大鼠生精细胞Fas蛋白表达影响。方法将30只4～5周龄雄性Wistar大鼠随机分为对照组、低剂量组、高剂量组。分别按0、10和20mg/kg染毒剂量隔日灌胃氟化钠(NaF)染毒39天,采用酸浸-氟离子选择电极法测定睾丸氟含量,用放射免疫法测定大鼠血清睾酮含量,用免疫组化(ICH)检测睾丸中Fas蛋白表达情况,同时镜检成熟精子质量。结果各染氟组大鼠睾丸氟含量均高于对照组(P0.05)且随染毒剂量的增加而逐渐升高;各染氟组大鼠血清睾酮含量低于对照组(P0.05),且随着染毒剂量的增加,睾酮含量逐渐降低;各染氟组大鼠生精细胞Fas蛋白阳性表达率高于对照组(P0.05),且随着染毒剂量的增加,Fas蛋白阳性表达率逐渐升高;各染毒组大鼠精子数量和精子活动率低于对照组(P0.05);精子畸形率高于对照组(P0.05)。结论染氟雄性大鼠血清睾酮水平降低,激活了生精细胞Fas/FasL系统,从而导致生精细胞损伤。     

碲化镉量子点对雄性小鼠精子质量和睾丸组织的毒性效应

[目的]探讨碲化镉量子点(CdTe quantum dots,CdTeQDs)对雄性小鼠精子质量和睾丸组织的影响。[方法]将32只雄性ICR小鼠随机分为4组,分别为对照组(pH=7.4的磷酸盐缓冲溶液)和低剂量(0.3μmol/kg)、中剂量(0.9μmol/kg)和高剂量(2.7μmol/kg)(以体重计,余同)CdTeQDs染毒组,每组8只。采用腹腔注射法隔日染毒1次,染毒3周。检测小鼠体重、生殖器官脏器系数、精子数量和精子畸形率、睾丸组织病理学及睾丸组织中乳酸脱氢酶(LDH)、琥珀酸脱氢酶(SDH)和超氧化物歧化酶(SOD)活性变化情况。[结果]染毒后,各组小鼠体重差异均无统计学意义(P0.05)。高剂量组小鼠睾丸脏器系数低于对照组(P0.05)。各组小鼠睾丸重量、附睾重量及脏器系数差异均无统计学意义(P0.05)。各剂量组小鼠精子数量与对照组[(3.35±0.76)×10~7/g]比较均减少(P0.05),高剂量组精子数量[(1.08±0.34)×10~7/g]比中剂量组[(1.73±0.61)×10~7/g]、低剂量组[(2.37±0.91)×10~7/g]减少(P0.05)。中剂量组[(13.09±3.09)%]、高剂量组[(18.29±2.25)%]小鼠精子畸形率与对照组[(4.16±0.53)%]、低剂量组[(5.07±0.83)%]比较均升高(P0.008);高剂量组与中剂量组比较,其精子畸形率升高(P0.008)。睾丸组织病理学观察结果显示,各剂量组染毒小鼠睾丸组织出现不同程度损伤。与对照组比较,各剂量组小鼠睾丸LDH和SOD活性无明显变化(P0.05),SDH活性下降(P0.05)。[结论]CdTeQDs会导致雄性小鼠精子数量减少,精子畸形率升高,睾丸组织受损以及睾丸SDH活性下降。     

敌敌畏、乐果和马拉硫磷混合染毒对雄性小鼠生殖功能的影响

目的 研究敌敌畏、乐果和马拉硫磷混合染毒后对雄性小鼠生殖功能影响的特点和可能机制。方法 将105只雄性ICR小鼠按体重分层随机分成7组,每组15只,即对照组(0 mg/kg),敌敌畏、乐果和马拉硫磷混合低( 10.8 mg/kg)、中(21.5mg/kg)、高剂量组(43.0 mg/kg),以及敌敌畏组(5.1 mg/kg)、乐果组(12.6 mg/kg)和马拉硫磷组(25.3 mg/kg),经口连续灌胃染毒35 d,每天1次。染毒第36天后处死动物。测量小鼠体重、精子活力,观察精子数量及精子畸形率,检测血清中性激素[包括睾酮(T)、卵泡刺激素(FSH)、黄体生成素(LH)、雌二醇(E2)等]的水平,并观察睾丸及附睾的病理及电镜下改变。结果 染毒后第14天,混合高剂量组小鼠体重[(22.40±3.07)g]低于对照组[(26.73±2.82)g](P＜0.05);染毒后第28天,混合中剂量组小鼠体重[(30.00±4.93)g]亦低于对照组[(33.13±3.29)g](P ＜0.05)。混合中、高剂量组精子数[分别为(321.17±18.19)×106/g附睾重、(225.00±19.67)×106/g附睾重]和精子活力[分别为(64.67±9.91)％、(57.83±9.66)％]均低于对照组[分别为( 373.33±14.65)× 106/g附睾重、(75.17±7.68)％](P值均＜0.05);精子畸形率[分别为(43.33 ±8.66)‰、(55.00±13.80)‰]高于对照组[(32.67±8.17)‰]（P值均＜0.05）;与对照组相比[FSH、E2、LH、T分别为(1.41±0.20)、(17.32±2.72)、(8.75±1.32)、（3.45±0.80）nmol/L],混合中、高剂量组小鼠血清中FSH[分别为(3.14±0.62)、(3.85±0.37) nmol/L]、E2[分别为(36.81±6.68)、（43.76±9.82）nmol/L]水平升高（P值均＜0.01）,LH[分别为(5.21 ±1.23)、(4.27±1.09) nmol/L]、T[分别为(1.37±0.38)、(0.73±0.18)nmol/L]水平降低（P值均＜0.01）。混合高剂量组小鼠睾丸成熟精子数减少,并可见结构异常的精子头、精子尾。结论 敌敌畏、乐果和马拉硫磷混合联合染毒可直接损害小鼠睾丸及附睾的结构和功能,而导致生殖细胞生成过程异常;并导致下丘脑-垂体-性腺轴性激素的分泌紊乱。     

烟草烟雾对大鼠生精细胞凋亡及血清睾酮和抑制素B水平的影响

目的探讨烟草烟雾对大鼠生精细胞凋亡及血清睾酮、抑制素B表达的影响。方法将40只8周龄雄性SD大鼠随机分成4组,分别为对照组及轻、中、重度吸烟组(每天分别暴露于4、8、12支香烟烟雾,早晚各1次),连续染毒8周后成功建立大鼠被动吸烟毒性模型。采用TUNEL法检测睾丸生精细胞凋亡数,分别以直接化学发光和ELISA法检测大鼠血清中睾酮、抑制素B的表达水平。结果对照组及轻、中、重度吸烟组大鼠生精细胞凋亡指数分别为(6.62±0.58)%,(7.08±1.02)%,(8.71±0.76)%,(10.17±1.18)%,各染毒组生精细胞凋亡指数均高于对照组,差异有统计学意义(P0.01)。各染毒组大鼠血清睾酮、抑制素B水平均低于对照组,且均随染毒剂量的增加而降低,差异有统计学意义(P0.05)。结论烟草烟雾可诱导大鼠睾丸生精细胞凋亡,并影响血清抑制素B及睾酮分泌。     

锌和维生素A对酒精致大鼠睾丸损伤的保护作用

[目的]观察锌和维生素A(VA)对长期摄入酒精致大鼠睾丸损害的保护作用及可能机制.[方法]40只健康雄性成年SD大鼠随机分为对照组、酒精组、酒精+葡萄糖酸锌组、酒精+VA组,各组每日分别灌胃给予酒精0、7.5 g/kg、酒精7.5 g/kg+葡萄糖酸锌7.7mg/kg、酒精7.5 g/kg+VA50μg/kg,连续13周.对各组大鼠的精子计数、精子活动率、精子畸形率、血清睾酮(T)、黄体生成素(LH)、卵泡刺激素(FSH)含量进行检测,光、电镜观察睾丸的形态改变.同时测定睾丸线粒体中丙二醛(MDA)的产生量,免疫组织化学法检测睾丸组织中iNOS的表达.[结果]与对照组相比,酒精组大鼠精子计数减少,精子活动率下降,精子畸形率升高(P＜0.05),血清T、LH、FSH水平明显降低(P＜0.05);睾丸生精上皮结构破坏,支持细胞和各级生精细胞均有退化变性;睾丸生精细胞iNOS表达明显增强(P＜0.05);睾九线粒体丙二醛含量明显升高(P＜0.05).与酒精组相比,葡萄糖酸锌组和VA组精子计数、精子活动率有所上升,生精细胞退化变性程度减轻,睾丸生精细胞iNOS表达减弱(P＜0.05),睾丸线粒体MDA减少,但血清T、LH、FSH水平仍低于对照组.[结论]长期摄入酒精不仅抑制精子发生和睾酮合成,还使下丘脑-垂体轴生殖内分泌功能受损.补充锌和VA可以限制酒精引起的睾丸过氧化损伤,保护睾丸的生精功能,但仍有生殖内分泌激素合成障碍.     

锌对镉致小鼠睾丸细胞凋亡及精细胞形态改变的保护作用

目的研究亚急性镉中毒致雄性小鼠睾丸细胞凋亡和锌干预作用。方法50只成年健康ICR小鼠,随机分为对照组、低剂量组、中剂量组、高剂量组和锌干预组,分别以不同剂量氯化镉溶液(0、0.4、0.8、1.6、1.6 mg/kg)行背部皮下注射,锌干预组同时给予硫酸锌溶液(3.50×10-4g/L)作饮用水自由饮用,连续染毒3周。检测精子活力、畸变和睾丸细胞凋亡。结果各组小鼠病理损伤自中剂量组开始出现,以高剂量组明显,锌干预组病理损伤小于高剂量组;各染毒组睾丸细胞凋亡率高于对照组,随剂量增加,低、中剂量组的凋亡率逐渐增高,而高剂量组凋亡率低于中剂量组,锌干预组凋亡率高于高剂量组。精子成活率随染毒剂量的增加而逐渐下降、畸形率则增加,呈剂量—反应关系;锌干预组精子成活率比高剂量组高,畸形率则显著降低。结论锌可降低镉中毒所致精子成活率下降和精子畸变率增高,但增加镉中毒时睾丸细胞凋亡率。     

农达对小鼠生精作用的影响

目的探讨农达(roundup,活性成分为草甘膦)对小鼠生精作用的影响。方法将24只成年SPF级雄性Balb/c小鼠随机分为阴性对照(蒸馏水)组和20、200、2 000 mg/kg农达染毒组,每组6只。采用经口灌胃方式进行染毒,染毒容量为20 ml/kg,每天1次,连续染毒30 d。测定小鼠精子数量、精子活动率和血清中睾酮(T)浓度及睾丸生精细胞的凋亡情况。结果与阴性对照组相比,200、2 000 mg/kg农达染毒组小鼠精子数量减少、精子活动度降低;各剂量农达染毒组小鼠血清睾酮浓度均降低,而睾丸生精细胞的凋亡率均升高,差异均有统计学意义(P0.05)。结论在本实验染毒时间和剂量范围内,农达对雄性Balb/c小鼠的生精功能有一定的毒性作用。     

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.     

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.