60Coγ射线对小鼠组织细胞氧化损伤的研究

目的：研究^60Coγ射线对小鼠组织细胞DNA的氧化损伤及其对组织抗氧化系统的影响。方法：小鼠接受^60Coγ射线全身一次性照射（吸收剂量分别为7Gy、10Gy、15Gy）后，用彗星试验对其肝、脾、肾及血液组织细胞DNA的完整性进行检测，并用比色法对红细胞超氧化物歧化酶（SOD）活性，全血谷胱甘肽过氧化物酶（GSH-Px）活性及肝匀浆丙二醛（MDA）含量进行测定。结果：各照射剂量组小鼠组织细胞拖尾率和拖尾细胞尾长比对照组显著增加（P〈0．05），并呈现良好的剂量反应关系。7Gy剂量组小鼠红细胞SOD活性及全血GSH-Px活性明显低于对照组（P〈0．05），而肝匀浆MDA含量则明显高于对照组（P〈0．05）。结论：^60Coγ射线照射可造成小鼠多组织细胞DNA完整性的损伤，破坏组织抗氧化系统并引起脂质过氧化水平增高。     

酸提水溶玉米芯硫酸酯化多糖对荷瘤小鼠血浆CuZn-SOD及MDA的影响

本研究探讨玉米芯硫酸酯化多糖制备及其对荷瘤小鼠机体抗氧化作用机制。方法：从玉米芯中提取酸溶性提取物，经中和、过滤、浓缩、醇析获得酸提水溶玉米芯粗多糖，经Sepharose CL-4B离子交换层析分离纯化，采用氯磺酸-吡啶法进行硫酸化修饰。采用黄嘌呤氧化酶法和硫代巴比妥酸（TBA）分光光度法分别测定荷瘤小鼠血浆CuZn—SOD的活力和MDA含量。结果：CCCS可以增加荷瘤小鼠血浆CuZn—SOD活力（P〈0．05），降低荷瘤小鼠血浆MDA的含量（P〈0．05）。结论：CCCS可以通过提高机体抗氧化能力。     

银耳多糖对D-半乳糖所致衰老小鼠抗氧化能力的影响

目的探讨银耳多糖（TP）对D-半乳糖所致衰老模型小鼠抗氧化能力的影响。方法ICR小鼠腹腔注射D-半乳糖建立衰老模型,同时给予不同剂量的TP,8周后获取小鼠心、脑,测定超氧化物歧化酶（SOD）、谷胱甘肽过氧化物酶（GSH-Px）活力以及丙二醛（MDA）的含量。结果TP各剂量组SOD和GSH-Px活力显著高于对照组（P〈0．05）,且高剂量TP组SOD、GSH-Px活力均高于低剂量和中剂量TP组（P〈0．05）;中、高剂量TP组MDA含量低于对照组（P〈0．05）且高剂量1]P组MDA含量低于低剂量TP组（P〈0．05）。结论TP对衰老模型小鼠抗氧化能力具有一定的正性调节作用。     

番茄红素对小鼠铅诱导的脂质过氧化的影响

目的观察染铅小鼠抗氧化系统的改变及番茄红素对抗氧化酶系统的影响。方法小鼠经饮水铅染毒（醋酸铅）造成铅中毒模型后给予番茄红素，4周后处死，测定血清和肝匀浆的超氧化物歧化酶（SOD）、谷胱甘肽过氧化物酶（GSH—PX）活力、丙二醛（MDA）含量。结果给予番茄红素的小鼠血清和肝组织的SOD活性、GSH—PX活力上升，MDA含量降低，与中毒模型组相比，在统计学上差异有显著性P〈0．05，结论铅中毒可引起小鼠过氧化损伤，番茄红素可以减轻铅中毒引起的脂质过氧化，提高小鼠机体的抗氧化能力。     

用彗星试验检测苯并(a)芘致小鼠体细胞DNA的损伤

[目的]建立彗星试验检测苯并（a）芘腹腔染毒小鼠体细胞DNA损伤的方法。[方法]雄性昆明种小鼠随机分为空白对照组、溶剂对照组和高、中、低剂量3个染毒组，每组4只。3个染毒组和溶剂对照组分别腹腔注射二甲基亚砜（0．01ml／g体重）和苯并（a）芘（250、125、62．50mg／g体重）。染毒3h后，处死小鼠，取出肝、肾和小肠组织制备单细胞悬液用于彗星试验。IMI彗星分析软件分析彗星尾距（oliver tail moment，TM）评价细胞DNA损伤的程度。[结果]高剂量组小鼠肝、肾和小肠细胞的彗星尾距值均增加，中、高剂量组小肠细胞的彗星尾距值均是溶剂对照组的5．22倍（P〈0．05）；中、高剂量组小鼠肾细胞的尾距值分别是溶剂对照组的8．27和7．16倍（P〈0．05）。高剂量组肝细胞的彗星尾距值是溶剂对照组的3．99倍。低剂量组仅小肠细胞的彗星尾距均值（1．285μm）增加（P〈0．05）。[结论]彗星试验可检测苯并（a）芘腹腔染毒小鼠肝、肾和小肠细胞的DNA损伤。     

洗涤剂对小鼠外周血淋巴细胞DNA损伤的研究

[目的]研究一定剂量的洗涤剂对小鼠外周血淋巴细胞DNA的损伤作用。[方法]分别以某洗涤剂低（1／1000 LD50）、中（1／200 LD50）和高（1／50 LD50）剂量行小鼠灌胃1次／d,并设阴性、阳性对照组。7d后采小鼠外周血以单细胞凝胶电泳法（SCGE）观察DNA损伤情况。[结果]低、中、高剂量均对小鼠外周血淋巴细胞DNA有损伤（与阴性对照组比,X^2=860．12,P〈0．01）;有剂量—反应关系（X^2=108．44,P〈0．01）。[结论]一定剂量的洗涤剂对小鼠外周血淋巴细胞DNA有损伤作用。     

蔓越莓对衰老小鼠和辐照小鼠抗氧化功能的影响

目的：探讨蔓越莓对小鼠的抗衰老作用及机制，观察其是否能有效地改善机体的抗氧化能力。方法：采用自然衰老和辐照两种模型小鼠分别给予不同剂量的蔓越莓30d，分别测定小鼠血及肝组织中超氧化物歧化酶（SOD）、谷胱甘肽过氧化物酶（GSH-Px）的活力和丙二醛（MDA）的含量。结果：蔓越莓能显著增强小鼠血及肝组织中SOD和GSH-Px的活力（P〈O．05）；降低小鼠血及肝组织MDA含量（P〈O．05）。结论：蔓越莓对自然衰老和辐照模型小鼠均有改善机体抗氧化能力。     

铅致小鼠睾丸DNA损伤与细胞增殖

目的研究慢性铅染毒对小鼠睾丸细胞毒性机制。方法应用单细胞凝胶电泳技术（SCGE），检测铅对雄性小鼠生殖细胞DNA损伤，四甲基偶氮噻唑蓝（MTT）实验检测睾丸细胞增殖功能，生化试剂检测细胞脂质过氧化损伤。结果从低剂量组到高剂量组铅均可引起睾丸生殖细胞DNA不同程度损伤；低（0．15％）、中（0．3％）、高（0．6％）DNA迁移长度及迁移率与对照组之间差异有统计学意义（P〈0．01）；中、高浓度铅具有抑制睾丸细胞增殖的作用，使睾丸丙二醛（MDA）升高、超氧化物歧化酶（SOD）、谷胱苷肽过氧化物酶（GSH-Px）活性降低。结论铅可致睾丸细胞脂质过氧化损伤，导致DNA链断裂损伤，且具有抑制睾丸细胞增殖作用。     

凹顶藻萜类化合物抑瘤作用及其机制研究

目的:观察凹顶藻萜类化合物(Laurencia terpenoid extract,LET)的抑瘤活性、免疫调节作用及对S180细胞凋亡的影响,初步探讨其抗癌作用机制。方法:采用Horn法检测其安全性(LD50)。建立S180荷瘤鼠动物模型,采用LET低、中、高剂量(25、50、100mg/kgbw)灌胃,空白对照组以大豆色拉油灌胃,每日一次,连续10d。测定抑瘤率;计算胸腺指数、脾指数;用MTT法测定脾淋巴细胞增殖活性;流式细胞术检测LET诱导的S180细胞凋亡和对细胞周期的影响。结果:LET的LD50>3160mg/kgbw属低毒。LET低、中、高三个剂量组的平均瘤重低于空白对照组(P<0.05),高剂量组的抑瘤率达39.1%。与空白对照组比较,LET低剂量组的胸腺指数上升、高剂量组的脾指数上升(P<0.05),LET低、中剂量组的脾淋巴细胞增殖率升高(P<0.05),高剂量组的脾淋巴细胞增殖率明显升高(P<0.01)。LET中剂量组S180细胞凋亡率高于空白对照组(P<0.05)。结论:LET使用安全,可明显抑制小鼠S180移植瘤的生长,其作用机制可能与其可提高机体的免疫功能,诱导S180细胞凋亡和阻断该细胞于G0/G1生长期有关。     

葡萄籽提取物抗氧化作用的研究

目的探讨葡萄籽原花青素提取物对老龄小鼠抗氧化能力的影响,为葡萄籽应用于人群食用提供实验依据。方法将40只雄性昆明种老龄小鼠按血液MDA水平随机分为对照组、葡萄籽提取物低、中、高剂量组,各组小鼠分别经口给予0.334、0.667、2.001g/kg.bw剂量的葡萄籽胶囊内容物及食用油30d后,按试剂盒说明测定MDA含量、SOD和GSH-Px活力。结果与老龄对照组比较,高剂量组能显著降低血中MDA含量（P〈0.05）和显著提高血清SOD活力（P〈0.05）,各剂量组对血清GSH-Px活力无明显影响（P〉0.05）。结论葡萄籽提取物具有抗氧化作用。     

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.