乙草胺原药的亚慢性毒性

按GB15670—1995《农药登记毒理学试验方法》,低、中、高剂量染毒组动物分别予含200、800、3200mg/kg96%乙草胺原药的饲料喂饲90d,阴性对照组动物喂饲标准饲料。结果显示,高剂量组动物各周体重明显低于对照组,肝脏、肾脏脏器系数及该组雄鼠睾丸脏器系数明显高于对照组;中、低剂量组动物各项指标与对照组比较差异无统计学或生物学意义。提示乙草胺原药对动物体重增长有抑制作用,其靶器官可能是肝脏、肾脏;雌、雄大鼠亚慢性经口毒性试验最大无作用剂量分别为65.1、59.6mg/(kg·d)。 更多还原     

苯醚甲环唑的亚慢性经口毒性

目的研究苯醚甲环唑原药对大鼠的主要亚慢性毒性作用及无明显损害作用剂量。方法按照GB 15670-1995《农药登记毒理学实验方法》中大鼠亚慢性经口毒性试验方法进行,设0、300、900、2 700 mg/kg 4个剂量组。结果中剂量组(900 mg/kg)雌性大鼠肝/体比、肾/体比高于对照组,雄性大鼠RBC计数、血容积比(HCT)低于对照组,高剂量组(2 700 mg/kg)雌性大鼠体重总增加量、总摄食量、总食物利用率低于对照组,肝/体比、肾/体比高于对照组,雄性大鼠肝/体比高于对照组,RBC、HGB、HCT、球蛋白(GLOB)平低于对照组,碱性磷酸酶(ALP)活力高于对照组。上述观察指标均存在剂量-效应关系。结论苯醚甲环唑原药的无明显损害作用剂量(NOAEL)为:雄性大鼠(20.94±2.64)mg/(kg.d),雌性大鼠(24.54±1.35)mg/(kg.d)。     

除草剂特丁津亚慢性毒性阈值分析

目的　应用基准剂量法 (BMD)和无明显损害作用剂量 (NOAEL)法分析特丁津 (Terbutryn ,2 -特丁胺基 -4 -氨 -6-乙胺基 -均三氮苯 )原药亚慢性毒性阈值并进行比较。方法　特丁津亚慢性毒性试验 (90d)设对照、低、中、高剂量组 (0、167、5 0 0、15 0 0mg/kg饲料 ) ,基准剂量计算采用EPA(美国国家环保局 )的BMDS软件。结果　中、高剂量组雌雄性大鼠食物利用率低于对照组 ,肾脏体系数高于对照组 ,高剂量组雌雄性大鼠生化指标BUN高于对照组 ,差异有统计学意义。中高剂量组少数动物出现肝脏、肾脏炎症小灶 ;低剂量组雌雄性大鼠均未见明显异常。特丁津原药NOAEL值雄性大鼠为11 80mg/(kg·d) ,雌性大鼠为 12 84mg/(kg·d)。特丁津原药的BMDL(基准剂量的可信限下限值 )雌雄大鼠分别为 10 0 2、9 77mg/(kg·d) ,均小于相应的NOAEL。结论　选择的BMD值在低剂量组和中剂量组之间 ,即BMD值大于NOAEL。而BMD的可信性下限BMDL值除了雄性大鼠单指标计算的BMDL值外 ,均小于NOAEL。     

基准剂量法在咪鲜胺锰盐亚慢性毒性研究中的应用

[目的 ]应用基准剂量法分析咪鲜胺锰盐 (tetrakis[N propyl N [2 ( 2 ,4,6 trichlorophenoxy)ethyl]imiazole 1 car boxamide]manganese(Ⅱ )chloridecomplex)原药亚慢性毒性试验结果 ,估算其基准剂量。 [方法 ]SD大鼠咪鲜胺锰盐亚慢性喂饲毒性试验 ( 90d) ,设对照、低、中、高剂量组 ( 0、111、3 3 3、10 0 0mg/kg饲料 )。观察指标有 :大鼠中毒症状及死亡情况、体重及摄食量变化、血液常规和生化及病理组织学变化。基准剂量计算采用EPA的BMDS软件。 [结果 ]雄性大鼠高剂量组肝体比、肾体比、睾体比及中剂量组肾体比 ,与对照组相比 ,差异有统计学意义 ;雌性大鼠高剂量组肝体比、肾体比及中剂量组肝体比 ,与对照组相比 ,差异有统计学意义 ;中、高剂量组少数动物出现肝脏、肾脏炎症小灶 ;低剂量组雌、雄性大鼠均未见明显异常。 [结论 ]咪鲜胺锰盐原药的无明显损害剂量 (NOAEL)雌、雄均为 111mg/kg饲料 ,按每日每千克体重摄入量计算 ,雌、雄大鼠NOAEL分别为 ( 9.0 7± 0 .2 7)、( 10 .3 2± 0 .66)mg/(kg·d)。咪鲜胺锰盐原药的基准剂量的 95 %可信限下限 (BMDL)值 ,雌、雄性大鼠分别为 12 1.0 6、13 4.5 1mg/kg饲料 ,按每日每千克体重摄入量计算BMDL值雌、雄性大鼠分别为 11.83、11.0 2mg/(kg·d) ,均略     

生物杀虫剂印楝素的亚慢性毒性

目的评价以印楝中提取的印楝素(AZ)为生物杀虫有效成分杀虫剂的亚慢性毒性,为AZ类杀虫剂的安全使用和管理提供科学依据。方法用AZ(20%原药)含量分别为0,0.04%,0.20%和1.00%的饲料喂饲雄性和雌性Wistar大鼠90 d。观察动物表现,记录动物体重和食物消耗量,进行血常规、血清生化、尿常规和解剖及组织病理学检查。结果动物表现、动物体重、食物消耗量、尿常规分析及组织病理学等均未显示与受试物处理相关的改变。染毒结束(90 d)时,雄性高剂量组红细胞(RBC)总数和血红蛋白(Hb)含量降低,雌性高剂量组Hb降低;雄性高、中剂量组血清总蛋白(TP)含量增高,雌性高、中剂量组碱性磷酸酶(ALP)减少,胆固醇(CHO)增高,TP增高,其他生化检测指标未发现有毒理学意义的改变。雄性高、中剂量组肝脏系数和高剂量组肾脏系数与对照组比较明显增高,雌性高、中剂量组肝脏系数增高。结论AZ(20%原药)亚慢性毒性相对较低,对造血系统和肝脏、肾脏可能有潜在的影响,对肾脏的影响推测为功能性改变。根据结果推断,0.04%AZ(20%原药)为本研究的最小可见有害作用水平(lowest observedadverse effect level,LOAEL),雌、雄性大鼠分别为每日50.2 mg/kg和45.6 mg/kg。     

三氯异氰尿酸对大鼠的亚慢性毒性

将SD大鼠按性别、体重随机分为高剂量组(1/8LD50)、中剂量组(1/16 LD50)、低剂量组(1/64LD50)和阴性对照组,分别喂饲相应的受试物饲料90 d,观察大鼠体重、血常规、尿常规、血清生化、脏体系数和组织病理学变化。结果与对照组相比,高剂量组雌性大鼠在染毒第70 d后生长明显减缓并持续到实验结束,AST、ALT活性明显升高;雄性大鼠睾丸脏体系数明显增大,AST、BUN显著升高。中剂量组雄性大鼠AST、BUN也明显增高。低剂量组各指标变化不明显。各剂量组脏器组织未见明显异常改变。提示三氯异氰尿酸原药对动物体重增长有抑制作用,对肝、肾功能有不良影响。经口染毒的亚慢性毒性阈剂量雌雄大鼠分别为99.25、49.62 mg/kg,最大无作用剂量雌雄大鼠分别为49.62、12.41 mg/kg。     

精喹禾灵的最大无作用剂量

目的研究精喹禾灵对大鼠的亚慢性毒性,求出最大无作用剂量。方法按照GB 15670-1995《农药登记毒理学试验方法》进行试验。结果1 300 mg/kg饲料组总摄食量、增重、食物利用率和睾丸/体比低于对照组,肝/体比、肾/体比高于对照组。病理组织学检查可见,4331、300 mg/kg饲料组大鼠睾丸组织形态学改变。结论精喹禾灵的最大无作用剂量为:雌性大鼠(33.42±1.56)mg/(kg.d),雄性大鼠(10.42±0.65)mg/(kg.d)。     

甲基磺草酮原药的毒性实验观察

目的了解受试样品甲基磺草酮原药的毒性特点和最大无作用剂量,为安全生产及慢性毒性实验提供剂量参考依据。方法依据GB15670-1995《农药登记毒理学试验方法》对其进行为期90天的毒性实验,依据《化妆品卫生规范》对其进行体外哺乳动物细胞染色体畸变试验和体外哺乳动物细胞基因突变试验。结果甲基磺草酮原药不诱发培养的哺乳动物细胞染色体畸变,体外哺乳动物细胞基因突变试验结果为阴性。在整个染毒期间,高剂量组雄性大鼠周平均体重从第4周开始至实验结束明显低于对照组(P0.01),中、高剂量组雄性大鼠WBC计数明显低于对照组(P0.01),高剂量组雌性大鼠的丙氨酸转氨酶(ALT)、碱性磷酸酶(ALP)活力明显高于对照组(P0.01),高剂量组雄、雌性大鼠的葡萄糖(GLU)明显高于对照组(P0.01),脏器系数测定结果表明,中、高剂量组雄性大鼠和高剂量组雌性大鼠肾脏系数明显高于对照组(P0.01),中、高剂量组雄、雌性大鼠肝脏系数明显高于对照组(P0.01、P0.05)。结论甲基磺草酮原药对中国仓鼠卵巢(CHO)细胞染色体畸变试验为无致畸变作用,对CHO细胞基因突变试验结果为无致突变作用。甲基磺草酮原药对雄、雌性大鼠经口染毒剂量为100.0mg/(kg.d)及以上时,对大鼠有毒性效应。甲基磺草酮原药对雄、雌性大鼠亚慢性经口毒性最大无作用剂量为25.0mg/(kg.d)。     

二甲酚草胺原药的大鼠亚慢性毒性

按GB15670—1995《农药登记毒理学试验方法》进行二甲酚草胺原药大鼠亚慢性经口毒性试验,设60、30、15 mg/kg二甲酚草胺原药剂量组和对照组。染毒14 d后60mg/kg组动物出现精神萎靡、被毛蓬松等中毒症状,雄性动物28 d后体重降低(P0.05);60 mg/kg组动物血生化中AST活性明显增高(P0.05);病理检查发现60 mg/kg组动物肝脏、肾脏、脑组织有一定程度的病理改变;30 mg/kg组动物肾、脑组织也见病理改变但程度较轻;15 mg/kg组各指标均未见明显异常。二甲酚草胺原药对雌雄性大鼠亚慢性经口毒性最大无作用剂量均为15 mg/kg。     

二甲戊灵大鼠亚慢性毒性实验研究

目的观察二甲戊灵(Pendimethalin)经口急性毒性和亚慢性毒性。方法采用SPF级SD大鼠进行经口急性及亚慢性毒性实验,试验期间观察动物一般情况,每周称量体重,试验结束后麻醉大鼠,检测血常规、血生化、尿常规、观察脏器系数及病理变化。结果二甲戊灵大鼠急性经口LD50雌性为2 710mg/kg.bw/d,雄性为3 160mg/kg.bw/d;亚慢性染毒后:240mg/kg.bw/d剂量组大鼠体重降低,雌雄性大鼠肾重量升高,脑、心、肝、脾、肾上腺脏器系数升高;雌性大鼠BUN,CHOL和CREA均升高,雄性大鼠BUN和CREA升高,但TBIL降低;少数雌性大鼠肾小管上皮细胞轻度空泡样变性;多数雄性大鼠出现不同程度的肾小管萎缩、管型、间质炎细胞浸润等。60mg/kg.bw/d剂量组第3、4周体重降低,雌性大鼠BUN、肾脏器系数、肝脏器系数均升高,雄性大鼠CREA升高,ALB降低。15mg/kg.bw/d剂量组各项指标与对照组相比,差异无统计学意义。结论本试验条件下,大鼠亚慢性经口毒性试验对SD大鼠的最大无作用剂量为15mg/kg.bw/d。二甲戊灵属低毒类农药。     

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.