阿维菌素原药的蓄积毒性和致突变性研究

研究新型农药阿维菌素原药的蓄积毒性和致突变性。对KM小鼠进行蓄积毒性试验、睾丸精母细胞染色体畸变试验和骨髓多染红细胞微核试验,以及鼠伤寒沙门氏菌回复突变(Am es)试验。结果表明:阿维菌素原药的蓄积毒性为轻度蓄积性;染色体畸变试验和骨髓微核试验阿维菌素组和阴性对照组差异无统计学意义(P>0.05),Am es试验阿维菌素组的回变菌落数均未超过自发回变菌落数的2倍,未呈现致突变性。 更多还原     

绿清灵致突变性和亚慢性经口毒性的研究

目的　研究农药绿清灵的致突变性和亚慢性经口毒性。方法　按GB15670 -1995的方法进行Ames试验、小鼠骨髓微核试验、小鼠睾丸精母细胞染色体畸变试验和大鼠亚慢性经口毒性试验。结果　Ames试验各条件下均为阴性。各剂量组骨髓微核细胞率和睾丸精母细胞染色体畸变率与阴性对照组比较差异均无显著性 (P >0 0 5)。亚慢性经口毒性试验中 ,各剂量组在一般状态、体重、血常规、血液生化、脏器系数等指标均基本正常 ;高剂量组动物部分脏器 (心、肝、肾、肺、脾、脑 )和中剂量组动物部分动物脏器 (心、肝、肾、肺 )有不同程度的病理表现 ;经综合分析 ,绿清灵在本试验对SD大鼠亚慢性经口的最大无作用剂量为 4 2mg·kg- 1·d- 1。结论　本受试物在本试验剂量下无致突变作用 ,亚慢性经口的最大无作用剂量可为本农药安全性评价和进一步试验提供依据     

S-生物烯丙菊酯亚慢性经口毒性和致突变性研究

目的研究农药S生物烯丙菊酯的致突变性和亚慢性经口毒性。方法按GB156701995的方法进行Ames试验、小鼠骨髓微核试验、小鼠睾丸精母细胞染色体畸变试验和大鼠亚慢性经口毒性试验。结果Ames试验各条件下均为阴性(0.5、5、50、500、5000μg/皿)。S生物烯丙菊酯2～40mg/kg剂量组骨髓微核细胞率和10～40mg/kg剂量组睾丸精母细胞染色体畸变率与阴性对照组比较差异均无显著性。亚慢性经口毒性试验中,各剂量组(2.9～38.5mg·kg-1·d-1)在一般状态、体重、脏器系数等指标均基本正常;高剂量组动物和中剂量组动物部分脏器(脑、心、肝、肾、肺、脾、睾丸)有不同程度的病理表现;经综合分析,S生物烯丙菊酯在本试验对SD大鼠亚慢性经口的最大无作用剂量为2.9mg·kg-1·d-1。结论本受试物在本试验剂量下无致突变作用,亚慢性经口的最大无作用剂量可为本农药安全性评价和进一步试验提供依据。     

新型农用杀菌剂氰菌胺致突变实验研究

目的探讨氰菌胺原药的致突变作用。方法小鼠骨髓嗜多染红细胞微核试验分别以1000、500、250mg/kg剂量经口给药2d,小鼠睾丸初级精母细胞染色体畸变试验分别以2000、1000、500mg/kg剂量经口给药5d,观察骨髓嗜多染红细胞微核率及睾丸初级精母细胞染色体畸变率。鼠伤寒沙门杆菌回复突变试验(Ames试验),选用TA97、TA98、TA100和TA102菌株,试验剂量为5000、1000、200、40μg/皿,观察各菌株的回变菌落数。结果小鼠骨髓嗜多染红细胞微核率及小鼠睾丸初级精母细胞染色体畸变率与阴性对照组比较,差异均无统计学意义(P0.05)。Ames试验,氰菌胺原药各剂量组的回变菌落数均未超过自发回变菌落数的2倍,亦未见剂量-反应关系,Ames试验结果为阴性。结论上述致突变试验结果表明氰菌胺原药无致突变作用。     

2-甲基-4-氯苯氧乙酸原药致突变性实验研究

目的探讨2-甲基-4-氯苯氧乙酸原药的致突变性。方法根据GB15670—1995《农药登记毒理学实验方法》,进行小鼠骨髓多染红细胞微核实验、睾丸精母细胞染色体畸变实验、鼠伤寒沙门氏菌回复突变(Am es)实验。结果小鼠骨髓多染红细胞微核率、睾丸精母细胞染色体畸变率与溶剂对照组相比,差异无显著性(P>0.05);Am es实验显示各菌株的各剂量组的回变菌落数均未超过自发回变菌落数的两倍。结论在本实验条件下,未发现2-甲基-4-氯苯氧乙酸原药具致突变性。     

杀菌剂十三吗啉的致突变性

目的研究杀菌剂十三吗啉原药的致突变性。方法小鼠骨髓多染红细胞微核试验剂量设为150、3006、00 mg/kg;小鼠睾丸精母细胞染色体畸变试验剂量设为163、326、652 mg/kg。Ames试验剂量设为5、50、500、1 000、5 000μg/皿。结果小鼠骨髓多染红细胞微核试验和小鼠睾丸精母细胞染色体畸变试验,各剂量组和阴性对照组比较,差异无显著意义(P>0.05);Ames试验中各测试浓度的回变菌落数均末超过自然回变菌落数的2倍。结论该试验范围内,未见十三吗啉原药有致突变性。     

十三吗啉原药的安全性评价

目的研究十三吗啉原药的急性和亚慢性毒性及致突变性,对其进行安全性评价。方法按照GB15670-1995《农药登记毒理学实验方法》进行实验。结果雌性大鼠急性经口LD50为562mg/kg,雄性大鼠为68lmg/kg,雌雄性大鼠急性经皮LD50均大于2000mg/kg。小鼠骨髓多染红细胞微核试验、小鼠睾丸精母细胞染色体畸变试验和Ames试验均为阴性。大鼠亚慢性经口毒性试验雌雄性大鼠的未见有害作用量(NOAEL)值分别为(7.47±0.61)mg/(kg·d)和(20.27±1.06)mg/(kg·d);雌雄性大鼠的基准剂量可信限下限(BMDL)值分别为25.58、35.57mg/(kg·d)。结论十三吗啉急性经口、经皮毒性均属低毒级,无致突变性。大鼠亚慢性经口毒性NOAEL值,雌雄结果差异较大,为克服其方法在评价中的不足,结果大鼠亚慢性经口毒性阈值采用BMDL值。     

甲氨基阿维菌素苯甲酸盐原药的致突变性及亚慢性毒性

目的 探讨甲氨基阿维菌素苯甲酸盐原药的致突变性及亚慢性毒性作用。方法 按照GB15670—1995《农药登记毒理学试验方法》进行Ames试验、小鼠骨髓嗜多染红细胞微核试验、小鼠睾丸精母细胞染色体畸变试验及大鼠亚慢性毒性试验。结果 （1）50～200μg/皿剂量组的Ames试验结果为阴性。（2）染毒6.25～50.00 mg/kg剂量组的微核率与阴性对照组比较差异无统计学意义（P〉0.05）,甲氨基阿维菌素苯甲酸盐原药不引起小鼠骨髓多染红细胞染色体断裂或整条染色体丢失。（3）染毒12.5～50.0 mg/kg剂量组的小鼠睾丸初级精母细胞染色体畸变率未见增加。（4）亚慢性毒性试验高剂量组部分动物在染毒后期出现全身震颤、精神不振、被毛蓬松、体重增长缓慢等中毒症状。实验结束时,高剂量组雌鼠淋巴细胞比例降低、中间细胞比例增高,肝脏脏器系数明显增高;雄鼠肾脏和脑的脏器系数增高。中、高剂量组雄鼠淋巴细胞比例降低、中间细胞比例增高,心脏脏器系数增高。结论 甲氨基阿维菌素苯甲酸盐原药无明显致突变作用。该药可引起动物出现神经系统症状,影响动物的生长发育及免疫功能。本实验提示,SD大鼠口服甲氨基阿维菌素苯甲酸盐原药90 d的最大无作用剂量为0.89 mg.kg-1.d-1。     

除草剂毒莠定原药的致突变性

目的　研究除草剂毒莠定原药的致突变性。方法　采用小鼠骨髓多染红细胞微核试验,剂量设为雄性13 1、2 61、5 2 2mg/kg、雌性2 3 0、460、92 0mg/kg ;小鼠睾丸精母细胞染色体畸变试验,剂量设为3 2 6、65 3、13 0 5mg/kg。Ames试验用TA97、TA98、TA10 0、TA10 2菌株,加与不加S9试验,剂量设为5、5 0、5 0 0、10 0 0、5 0 0 0 μg/皿。结果　小鼠骨髓多染红细胞微核试验和小鼠睾丸精母细胞染色体畸变试验,各剂量组和阴性对照组比较,差异无显著性(P >0 0 5 ) ;Ames试验中各测试浓度的回变菌落数均末超过自然回变菌落数的2倍。结论　该试验范围内,未见毒莠定原药有致突变性。     

溶菌灵毒性研究

溶菌灵原药对大鼠的急性经口毒性和急性经皮均为低等毒性，对家兔皮肤及眼粘膜无刺激作用。Ａｍｅｓ试验、小鼠骨髓嗜多染红细胞微核试验和小鼠睾丸初级精母细胞染色体畸变试验结果均为阳性。     

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.