β-胡萝卜素对香烟烟气诱导脂质过氧化的交互作用

目的　研究 β 胡萝卜素对香烟烟气诱导脂质过氧化的交互作用。 方法　建立了大鼠肺Ⅱ型细胞体外培养模型 ,加入 β 胡萝卜素或 和香烟烟气颗粒提取物染毒 2 4h后 ,检测细胞的丙二醛 (MDA)含量。并构建短期动物模型 ,使小鼠暴露于香烟烟气和 或补充 β 胡萝卜素 10天 ,检测血清MDA的含量。结果　在大鼠肺Ⅱ型细胞模型中 ,随香烟烟气颗粒提取物的含量增加 ,MDA水平明显上升 ,而 β 胡萝卜素各剂量组间MDA水平的差异无显著性。0 5 μg ml的 β 胡萝卜素可抑制香烟烟气颗粒提取物对肺细胞脂质过氧化的诱导作用 ,表现为拮抗作用。在小鼠动物模型中 ,烟气暴露组的MDA水平显著高于正常对照组 ,而 β 胡萝卜素各剂量组间MDA水平的差异无显著性。给予 β 胡萝卜素 2 5mg kgBW的烟气暴露组小鼠血清中MDA水平下降。结论　β 胡萝卜素对香烟烟气诱导的脂质过氧化具有拮抗作用 ,其有效作用剂量在大鼠肺Ⅱ型细胞实验中为 0 5 μg ml ,在小鼠实验中为 2 5mg kgBW。     

β-胡萝卜素在吸烟诱导人胚肺二倍体细胞DNA损伤中的作用

[目的 ]探讨 β 胡萝卜素在吸烟诱导DNA损伤中的作用机制。[方法 ]人胚肺二倍体细胞SL 7单细胞电泳分析 (彗星试验 ) β 胡萝卜素和吸烟水溶性物质 (CSS)单独及联合作用 ,结合抗氧化剂VitE干预试验。[结果 ] 0 5～ 10μmol/Lβ 胡萝卜素单独作用不产生DNA断裂。 1∶10和 1∶2 0稀释CSS诱导彗星形成率分别达到 84%和 68% ,0 5和 1 0μmol/Lβ 胡萝卜素保护CSS对DNA损伤作用具有显著意义 ,但当 β 胡萝卜素浓度高 10倍时 ,则失去保护作用。 5 0 μmol/LVitE能有效抑制氧化损伤。 [结论 ]CSS可以诱导人胚肺二倍体细胞DNA损伤 ;β 胡萝卜素具有保护CSS诱导细胞DNA损伤作用 ,但当剂量升高至 5 0～ 10 0 μmol/L时 ,则失去保护作用 ,这可能与高浓度 β 胡萝卜素原氧化作用有关     

β-胡萝卜素辅致癌机制体外实验研究

[目的 ]建立改进的BALB/c 3T3细胞转化试验方法 ,简便、快速检测 β 胡萝卜素通过诱导细胞色素P45 0酶提高苯并 (a)芘、吸烟焦油致癌作用。 [方法 ]每组 12瓶细胞 ,每瓶接种 10 4细胞 ,2 4h后加受试物 ,1周后 2瓶细胞用结晶紫方法测定细胞毒性 ,其余 10瓶换含 2 %胎牛血清和 1%ITES( 2 0 0 μg/ml胰岛素 ,2 0 0 μg/ml人转铁蛋白 ,12 2 μg/ml氨基乙醇 ,0 0 3 4μg/ml亚硒酸钠 )DMEM /F12转化表达培养液。每周换液 2次 ,第 2 5天甲醇固定 10min ,2 5 %Giemsa染色 5～ 10min ,肉眼计数直径 >2mm转化灶。 [结果 ] 0 5、1μmol/Lβ 胡萝卜素、10 μmol/Lα 萘黄酮、10 μmol/L苯并 (a)芘和 2μg/ml吸烟焦油对细胞相对存活率均大于 90 %。 1μmol/Lβ 胡萝卜素能提高苯并 (a)芘、吸烟焦油的细胞转化率平均每瓶细胞转化灶分别增高 3 2 %和 5 0 0 %。α 萘黄酮可以抑制 β 胡萝卜素增强吸烟焦油和苯并 (a)芘细胞转化作用。[结论 ]β 胡萝卜素增强苯并 (a)芘和吸烟焦油对BALB/c 3T3细胞转化能力 ,可被混合功能氧化酶抑制剂α 萘黄酮阻止 ,提示 β 胡萝卜素辅致癌作用是通过诱导细胞色素P45 0酶所致     

烹调烟雾冷凝物对DNA完整性影响的研究

采用体外作用的方式探讨烹调烟雾致遗传损伤的机制。通过细胞毒性试验得出 :油烟冷凝物与大鼠肺Ⅱ型细胞生长抑制率之间存在剂量 -效应关系 (r=0 943,P <0 0 1) ,剂量在 2 0 μg ml及以上对细胞有明显毒性作用。在不产生细胞毒性作用的剂量范围内 ,单细胞凝胶电泳试验表明 :大鼠肺Ⅱ型细胞经油烟冷凝物染毒 2小时可引起细胞DNA链断裂 ,在 0～ 5 μg ml剂量范围内 ,损伤程度与剂量存在直线相关关系 (r=0 918,P <0 0 5 ) ;在 10 μg ml剂量下 ,DNA损伤已达最大程度。发生DNA损伤的细胞经修复培养 2小时后受损伤的DNA能被修复。油烟冷凝物对 30 μg小牛胸腺DNA交联试验显示 :在 5 0～ 80 0 μg剂量范围 ,DNA交联率与受试物间存在剂量 -效应关系 (r=0 96 3,P <0 0 1)。提示烹调烟雾冷凝物在较低作用剂量下就可导致大鼠肺Ⅱ型细胞DNA损伤 ,在一定剂量下可以导致DNA交联率的增加     

微囊藻毒素-LR对睾丸支持细胞活性及凋亡基因表达的影响

[目的]研究微囊藻毒素-LR对睾丸支持细胞活性的影响及其对细胞凋亡相关基因表达的影响. [方法]分离纯化大鼠睾丸支持细胞,用低剂量(0～500×10-3 μg/ml)和高剂量(1～20 μg/ml)微囊藻度素-LR染毒细胞,细胞培养24 h、48 h和72 h后,用四甲基偶氮唑蓝(MTT)实验和中性红吸收(NR)实验检测微囊藻毒素-LR对支持细胞活性的影响;将纯化后的部分睾丸支持细胞接种于6孔板中,给予不同剂量的微囊藻毒素-LR (0,1,10μg/ml),于24h和48 h后提取细胞总RNA,RT-PCR方法检测细胞中凋亡相关基因P53、bax和bcl-2表达水平.[结果]低剂量(0～500×10-3 μg/ml)微囊藻毒素-LR作用于支持细胞24、48、72 h,细胞活性增强.高剂量微囊藻毒素-LR(10和20μg/ml)作用24、48 h,细胞活性显著降低.时闻效应实验结果显示随着暴露时间的延长细胞活性降低.细胞暴露于1 μg/ml微囊藻毒素-LR后与对照组细胞相比较P53和bcl-2 mRNA水平相对表达量增加,bax表达量降低.暴露予10 μg/ml微囊藻毒素-LR后P53和bax mRNA水平相对表达增加,bcl-2表达降低.[结论]低剂量的微囊藻毒素-LR对 细胞具有兴奋效应,随着剂量的增高及暴露时间的延长微囊藻毒素-LR能够明显抑制细胞活性.同时微囊藻毒素-LR可通过P53、bax和bcl-2基因的表达影响睾丸支持细胞的凋亡.     

β-胡萝卜素抑制人肝癌细胞株SMMC-7721增殖的研究

为了探讨 β 胡萝卜素抑制肝癌细胞增殖的机制 ,在体外培养肝癌细胞株SMMC 772 1,培养基添加2 0、40及 80 μmol Lβ 胡萝卜素作用 12、2 4和 48h后 ,用四唑盐比色试验 (MTT)检测细胞的存活和生长 ;台盼蓝拒染法绘制生长曲线 ;DNA凝胶电泳检测肝癌细胞凋亡。MTT检测结果显示 2 0～ 80 μmol L的 β 胡萝卜素均对SMMC 772 1细胞株有显著的抑制作用 ,且呈剂量 效应关系。DNA凝胶电泳结果显示 β 胡萝卜素能够诱导SMMC 772 1细胞凋亡。结论认为 β 胡萝卜素对人肝癌细胞株SMMC 772 1的增殖具有显著的抑制作用 ,其机制可能是通过干扰肝癌细胞的DNA代谢和诱导肝癌细胞凋亡     

汽车尾气中含铂颗粒物与非含铂颗粒物肺毒性比较

[目的]探讨使用三元催化转换器(TWC)后汽车尾气中含铂颗粒物与未使用TWC的汽车尾气中非含铂颗粒物肺毒性的差异。[方法]选择雄性Wistar大鼠(每组6只,8组),分别气管滴注低(1．6 mg/kg体重)、中(8 mg/kg体重)、高(40 mg/kg体重)剂量的含铂和非含铂颗粒物,另设生理盐水组和空白对照组。气管一次滴注量为1．5 ml/kg体重,连续 3 d。计算肺灌洗液中各类白细胞百分比,测定乳酸脱氢酶(LDH)、酸性磷酸酶(ACP)等细胞毒性及细胞氧化损伤指标, 计算2种颗粒物的毒性指数,并进行比较。[结果]2种颗粒物中、高剂量染毒组肺灌洗液中细胞毒性指标及细胞氧化损伤情况均有不同程度的升高,呈一定的剂量反应关系;但非含铂颗粒物的各指标变化程度大干含铂颗粒物,毒性指数也大于含铂颗粒物。[结论]汽车尾气中非含铂颗粒物的肺毒性大干含铂颗粒物,可能是由于较强的氧化损伤能力造成的。     

香烟烟气氧化损伤:β-胡萝卜素效应

[目的]研究β胡萝卜素在香烟烟气氧化损伤中的生物学效应。[方法]应用脱氧核糖(DR)降解方法和质粒DNA方法检测香烟烟气水溶液氧化损伤和β-胡萝卜素作用。[结果]香烟烟气水溶液生成大量活性氧类(ROS)自由基，如O2^-，H2O2，OH^-，活性氧类自由基强有力诱发DR降解和DNA损伤。β-胡萝卜素在高浓度香烟烟气水溶液DR降解中显示弱保护作用，在低浓度香烟烟气水溶液质粒DNA损伤试验中显示强有力的保护作用。[结论]香烟烟气水溶液生成大量长寿命活性氧类自由基，β-胡萝卜素显示了抗香烟烟气氧化损伤效应。     

双酚A和β-六氯环己烷对小鼠雌激素活性的实验研究

目的　利用无内源性雌激素模型小鼠 ,探讨双酚A(BPA)和 β-六氯环己烷 (β -HCH)单独与联合投予时的雌激素活性。方法　手术切除小鼠双侧卵巢 17天后 ,给予不同剂量雌二醇 (17β -E2 )并建立其与子宫脏器系数和POD(过氧化物酶 )活性的剂量效应关系。单独或联合腹腔注射给予BPA和 β -HCH ,测定雌激素活性。 结果　 17β -E2剂量与子宫脏器系数和POD活性之间有剂量效应关系。BPA高剂量组子宫脏器系数和POD活性均升高 (P <0 0 5、P <0 0 1)。β -HCH高剂量组使子宫脏器系数升高 (P <0 0 1) ,而POD活性升高无显著性差异 (P >0 0 5 )。在联合投予实验中 ,子宫脏器系数均未见协同作用。而BPA和 β -HCH剂量为 10 0和 5 0 0 μmol/kg体重时对POD活性呈现出协同作用。结论　BPA和 β -HCH单独作用时 ,在一定剂量范围内有雌激素活性。两者联合作用时 ,在一定浓度下表现出协同作用。     

镍冶炼烟尘致NIH3T3细胞形态转化作用的实验研究

目的　研究镍冶炼工人接触烟尘的生物学效应。方法　以来自我国两家镍冶炼厂的镍冶炼烟尘为受试物 ,处理小鼠NIH3T3细胞 ,观察细胞吞噬活性、毒性和转化活性 ,预测镍冶炼烟尘的致癌危险性。结果　 (1)两种镍冶炼烟尘均可被NIH3T3细胞吞噬 ,两样品在 10 0 .0 0 0 μg/ml剂量的吞噬率分别为6 9 .0 %、39.0 % ,2 0 0 .0 0 0 μg/ml剂量的吞噬率分别为 78.0 %、4 7.0 % ,差异均有显著性 (P <0 .0 1)。剂量为12 .5 0 0～ 10 0 .0 0 0 μg/ml时 ,两样品的相对克隆形成率分别为 71.1%～ 3.9%和 84 .4 %～9.1%。两种镍冶炼烟尘以克隆形成率表示的细胞毒性与Ni2 O3 接近 ,高于TiO2 ,而低于阳性对照物N 甲基 N’ 硝基 N 亚硝基胍 (MNNG)。 (2 )MNNG、Ni2 O3 和两份镍冶炼烟尘均可诱发NIH3T3细胞发生形态转化 ,两种镍冶炼烟尘在 12 .5 0 0～ 5 0 .0 0 0 μg/ml范围内的转化率分别为 1.9%～ 3.6 %和 0 .9%～ 2 .5 %。 (3)MNNG和镍冶炼烟尘处理的NIH3T3细胞均可与刀豆素A(ConA)发生凝集反应 ,并能在软琼脂培养基中形成集落 ,验证了转化克隆的可靠性。结论　镍冶炼烟尘具有细胞转化活性 ,为镍冶炼烟尘的致癌危险性以及镍冶炼工肺癌的病因学研究提供了新的实验室证据。     

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.     

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.     

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.     

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.