维生素C对肺泡巨噬细胞脂质过氧化及抗氧化酶的影响

目的 探讨维生素C拮抗镍所致细胞毒作用及作用机理。方法 采用体外细胞培养方法，观察维生素C对染镍肺泡巨噬细胞包膜脂质过氧化产物丙二醛（MDA）及超氧化物歧化酶（SOD）活性的影响。结果 在体外染镍肺泡巨噬细胞培养过程中加入不同浓度维生素C（25，50和100μmol/L）可提高肺泡噬细胞间SOD活性，具剂量反应关系。维生素C能显著抑制MDA生成量，其中以50和100μmol/L浓度组作用最为明显。结论 镍可致细胞脂质过氧化，维生素C具有拮抗镍所致细胞毒性的作用，可能与其抗氧化功能有关。     

β-胡萝卜素对染镍肺泡巨噬细胞MDA及SOD的影响

目的：探讨β－胡萝卜素拮抗三氧化二镍的细胞毒作用及其机理，方法：采用体外细胞培养方法，观察β－胡萝卜素对染镍肺泡巨噬细胞膜脂质过氧化产物丙二醛（MDA）及超氧化物歧化酶（SOD）活性的影响。结果：在体外染镍肺泡巨噬细胞培养过程中加入不同浓度β－胡萝卜素（25，50和100μmol/L）可提高肺泡巨噬细胞内SOD活性，呈剂量－反应关系，维生素E能显抑制MDA生成量，其中以50μmol/L和100μmol/L浓度组作用最为明显，结论：镍可致细胞脂质过氧化，β－胡萝卜素具有拮抗镍所致细胞毒性的作用，可能与其抗氧化功能有关。     

维生素C对镍诱导的肺泡巨噬细胞氧化损伤的保护作用

目的:研究维生素C(VC)拮抗Ni2O3的细胞氧化损伤的作用及对大鼠肺泡巨噬细胞iNOS诱导表达的影响。方法:采用体外细胞培养法测定在VC(25,50,100μmol/L)作用下,体外染镍肺泡巨噬细胞的死亡率及活力。同时观察细胞内丙二醛(MDA)、一氧化氮(nitricoxide,NO)和活性氧(ROS)的产生;超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)、过氧化氢酶(CAT)、诱导型一氧化氮合酶(nitricoxidesynthase,iNOS)活力的变化以及应用RT-PCR法测定iNOSmRNA的表达。结果:在体外染镍肺泡巨噬细胞中加入不同浓度的VC后可降低该细胞的死亡率并提高细胞的活力,可减少MDA、NO和活性氧的产生,降低NOS的活性,提高SOD、GSH-Px、CAT的活性,iNOSmRNA表达也较镍组降低。结论:镍可致细胞脂质过氧化,VC可通过提高抗氧化酶的活性,抑制iNOSmRNA的表达,减少活性氧及NO的产生,拮抗镍对肺泡巨噬细胞的氧化损伤。     

维生素C对染镍肺泡巨噬细胞iNOS的影响

目的 探讨镍在大鼠肺泡巨噬细胞诱导型一氧化氮合成酶(iNOS)基因诱导表达中的作用，以及维生素C对巨噬细胞iNOS诱导表达的影响及其机制。方法 采用体外细胞培养法测定在维生素C(25，50，100μmol／L)作用下，体外染镍肺泡巨噬细胞的存活率及活力。同时观察细胞内一氧化氮(nitric oxide，NO)和活性氧的产生，以及一氧化氮合酶(nitric oxide synthase，NOS)活力的变化。以逆转录-聚合酶链反应(RT—PCR)法测定iNOS mRNA的表达。结果 在体外染镍肺泡巨噬细胞中加入不同浓度的维生素C后可提高该细胞的存活率和活力，可减少NO和活性氧的产生，降低NOS和活性，还可抑制镍诱导的iNOS mRNA的表达水平。结论 镍可通过诱导大鼠肺泡巨噬细胞．NOS基因表达，产生大量NO，导致细胞脂质过氧化，而维生素C可通过抑制iNOS mRNA的表达，拮抗镍对肺泡巨噬细胞的细胞毒作用。     

β-胡萝卜素对染镍肺泡巨噬细胞抗氧化酶活性的影响

目的：研究β－胡萝卜素拮抗三氧化二镍的细胞毒作用。方法：采用体外细胞培养法测定在β－胡萝卜素（25，50，100μmol/L）作用下，体外染镍肺泡巨噬细胞（AM）的存活率及活力。同时观察细胞内活性氧的产生，以及过氧化氢酶（CAT）和谷胱甘肽过氧化物酶（GSH－Px)活力的变化。结果：在体外染镍肺泡后噬中加入不同浓度的β－胡萝卜素后可提高该细胞的存活率和活力，可增强细胞内CAT、GSH－Px的活性，其中以100μmol/L的β－胡萝卜素最为明显。结论：镍可致细胞脂质过氧化，β-胡萝卜素具有拮抗镍对肺泡巨噬细胞的细胞毒作用，可能与抗氧化损伤有关。     

硒对染尘肺泡巨噬细胞脂质过氧化和抗氧化酶影响的实验研究

目的探讨硒(Se)抗石英尘的细胞毒作用及其机理.方法采用体外细胞培养法,观察在不同浓度硒作用下,染石英尘的肺泡巨噬细胞(AM)膜脂质过氧化物丙二醛(MDA)生成量和AM内抗氧化酶-超氧化物歧化酶(SOD)活性.结果在体外染石英尘中加入硒有效抑制AM膜丙二醛生成量,其中以1.0×10-4mo/L硒作用最为明显,并可提高AM内超氧化物歧化酶活性,且有一定的剂量反应关系.结论硒具有抗石英尘对肺泡巨噬细胞脂质过氧化的作用.     

几种抗氧化剂拮抗染砷小鼠毒作用的实验研究

目的 :研究锌、维生素 C、维生素 E、二巯基化合物这几类抗氧化剂对砷染毒小鼠毒作用的拮抗作用。方法 :昆明种小鼠饮用含砷水同时通过灌胃给予不同种类的抗氧化剂 ,8周后 ,测定小鼠肝脏超氧化物岐化酶 (SOD)活性及丙二醛 (MDA)含量。结果 :干预后 ,与砷染毒对照组比较 :维生素 C组、维生素 E组、巯基组的 SOD活性升高 ,MDA含量下降 (P<0 .0 5 )。锌制剂组仅 SOD活性升高 ;与正常对照组比较 :维生素 C组、维生素 E组的 SOD活性和 MDA含量达到正常对照组水平 ,锌制剂组的 SOD活性与巯基组的 MDA含量分别达到正常对照组水平 (P>0 .0 5 )。结论 :一定剂量的锌制剂、维生素 C、维生素 E、二巯基化合物对砷染毒小鼠毒作用有拮抗作用。其中维生素 C、维生素 E的拮抗作用强 ,能完全纠正染砷小鼠的脂质过氧化的损伤 ,而锌制剂与二巯基化合物有一定的拮抗作用。     

维生素对肺泡巨噬细胞NOS活性的影响

目的 研究维生素E(VE)和维生素C(VC)拮抗石英粉尘细胞毒的作用及机制。方法 采用体外细胞培养法测定在不同浓度的VE和VC的共同作用下，体外染石英尘肺泡巨噬细胞(AM)的存活率和细胞活力，同时观察细胞内一氧化氮和活性氧的产生以及一氧化氮合酶活性的变化。结果在体外染石英尘肺泡巨噬细胞中加入不同浓度的VE和VC后可提高该细胞的存活率，降低NOS的活性，减少NO和活性氧的产生，尤以100μmol／LVE和100μmol／LVC作用组效果最为明显。结论 VE和VC具有拮抗石英尘对肺泡巨噬细胞的细胞毒作用，具有保护AM的作用。     

锰化合物对神经母细胞瘤细胞SH-SY5Y脂质过氧化的作用

[目的 ]通过锰染毒神经母细胞瘤细胞 (SH SY5Y) ,观察脂质过氧化及其相关酶水平的改变 ,探讨锰对SH SY5Y的脂质过氧化及相关酶活性的影响 ,为进一步研究锰神经毒作用的机制提供科学依据。 [方法 ]采用浓度为 0 .2 5、0 .5 0、0 .75mmol/L的二价锰和三价锰 ,分别对体外培养的SH -SY5Y细胞染毒 2 4h ,测定超氧化物歧化酶 (SOD)、丙二醛(MDA)、谷胱甘肽 (GSH)、谷胱甘肽过氧化物酶 (GSH Px)和过氧化氢酶 (CAT)的活性。 [结果 ]二价锰和三价锰均可引起SOD、MDA、GSH、GSH Px和CAT活性的改变 ,其中SOD、GSH、GSH Px和CAT活性与对照组比较差异均有显著性 (P <0 .0 5或P <0 .0 1) ,且存在剂量 效应关系。而MDA含量则较对照组升高 (P <0 .0 1) ,且随染毒浓度增高而上升。 [结论 ]一定浓度的锰化合物可使SH SY5Y细胞脂质过氧化反应增强 ,引起相关酶活性的改变。提示这种变化很可能是锰对神经细胞发挥毒作用的重要途径之一。     

维生素E联合维生素C对染石英尘肺泡巨噬细胞脂质过氧化和抗氧化酶的影响

目的 探讨维生素E与维生素C联合抗石英尘细胞毒作用及其机制。方法 采用体外细胞培养法，研究不同浓度维生素E与维生素C对染色英尘的肺泡巨噬细胞（AM）膜脂质过氧化和抗氧化酶的影响。结果 在染石英尘的AM中加入维生素E与维生素C，可以减少活性氧，丙二醛的生成，与石英组比较，差异有显著性；而过氧化氢酶，谷胱甘肽过氧化物酶，超氧化物歧化酶的活力和细胞活力高于石英组。结论 维生素E联合维生素C对染石英尘的肺泡巨噬细胞具有保护作用。     

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.     

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.