构树叶总黄酮对表皮细胞防护作用研究

目的 研究构树叶提取物构树总黄酮(total flzvonoids of broussonetia papyrifera,TFBP)对铅、砷染毒的人永生化表皮细胞氧化损伤的防护效果。方法 在人永生化表皮细胞培养的基础上,在0．1mmol／L的醋酸铅、5．0μmol／L的亚砷酸钠的染毒体系中,分别加入0～200mg／L TFBP,测定细胞裂解液中丙二醛(MDA)含量和超氧化物歧化酶(SOD)和谷胱甘肽过氧化酶(GSH-Px)的活力,评价TFBP的抗氧化效果。结果 0．1mmol／L的醋酸铅对细胞染毒产生氧化损伤,而添加高于100mg／L TFBP后,MDA含量由4．23nmol／mg Pro降低到1．87nmol／mg Pro,SOD活力由25．90 U／mg Pro增加到37．12U／mg Pro,但GSH-Px的活力变化不大。砷 TFBP 150mg／L、200mg／L组与砷染毒组相比,GSH-Px和SOD活力差异有显著性。结论 该试验条件下,TFBP对铅、砷染毒的人永生化表皮细胞氧化损伤有防护效果。     

构树总黄酮对长波紫外线引起人角质形成细胞损伤的防护作用

目的研究长波紫外线(UVA)照射对人角质形成细胞的氧化损伤以及构树总黄酮(totalflavonoids of broussonetia papyrifera,TFBP)的防护效果。方法在人角质形成细胞培养的基础上,实验组在照射前加入不同剂量的TFBP,然后和处理组一起接受UVA照射,通过噻唑蓝(MTT)染色法检测细胞活性、裂解液中丙二醛(MDA)含量和超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)活力,对构树叶提取物的抗氧化效果进行评价。结果随着UVA剂量的增高(0.46~2.76J/cm2),细胞的活性逐渐降低(96.3%~37.5%),添加TFBP10~200mg/L后,细胞活性升高,MDA含量由(5.14±0.58)nmol/mg pro降低到(2.98±0.14)nmol/mg pro,SOD活力由(23.09±3.91)U/mg pro增加到(34.50±1.59)U/mg pro,GSH-Px活力也有所升高。结论本试验条件下,UVA对人角质形成细胞有明显的氧化损伤,TFBP对这种氧化损伤有防护作用。     

亚砷酸钠对人支气管上皮细胞的氧化损伤作用

目的 探讨不同浓度亚砷酸钠对永生化人支气管上皮细胞氧化损伤的影响.方法 体外培养永生化人支气管上皮(HBE)细胞,加入终浓度为0～50000 μmol/L的亚砷酸钠溶液暴露24h,测定细胞活性;加入终浓度为0～6μmol/L的亚砷酸钠溶液暴露24h,测定活性氧(ROS)、丙二醛(MDA)含量和超氧化物歧化酶(SOD)活力及细胞DNA链断裂情况.结果 与对照组比较,各浓度亚砷酸钠染毒组HBE细胞内ROS、MDA含量和Olive尾矩均显著升高,细胞存活率和SOD活力均显著下降,差异有统计学意义(P＜0.05);且随着亚砷酸钠染毒浓度的升高,HBE细胞内MDA、ROS含量和Olive尾矩均呈明显的上升趋势(P＜0.05),细胞存活率和SOD活力均呈明显的下降趋势(P＜0.05).结论 亚砷酸钠可以诱导HBE细胞氧化损伤增加,提示氧化应激可能是亚砷酸钠致HBE细胞毒作用机制之一.     

无机砷对人皮肤成纤维细胞增殖毒性的实验观察

目的观察亚砷酸钠诱导体外培养的人皮肤成纤维细胞的作用，探讨砷性皮肤损伤的分子机制。方法通过直接细胞计数法和噻唑蓝（MTT）还原法检测亚砷酸钠对皮肤成纤维细胞生长的影响。结果与对照组比较，皮肤成纤维细胞经不同剂量的亚砷酸钠诱导后，吸光度值均有改变，存在剂量效应关系（P〈0.01）。0．5～5．0μmol／L浓度的亚砷酸钠对皮肤成纤维细胞有明显的增殖作用，而10μmol／L浓度的亚砷酸钠产生明显的毒性作用。结论低浓度NaAsO2、NaAsO2刺激人皮肤成纤维细胞增殖，高浓度具有细胞毒性。     

双苯氟嗪对铅致海马神经元损伤的保护作用

目的 观察双苯氟嗪（Dipfluzine，Dip）对铅致原代培养海马神经元损伤的保护作用，并探讨其作用机制。方法 以原代培养的海马神经元作为研究对象，用醋酸铅造海马神经元损伤模型，通过测定细胞存活率，乳酸脱氢酶（LDH）泄漏率和胞内游离钙浓度（[Ca^2＋]i），观察Dip对铅致原代培养海马神经元损伤的保护作用。结果 Dip1．0和10μmol／L可显著提高铅损伤海马神经元存活率，降低LDH泄漏率，对铅诱导的海马神经元[Ca^2＋]i升高有明显的抑制作用（P〈0．01）；Dip0．1μmol／L亦可抑制铅诱导的海马神经元[Ca^2＋]i升高（P〈0．05）。结论 Dip对铅致原代培养海马神经元损伤具有保护作用，其机制可能与其抑制铅诱导的胞内钙超载有关。     

铅作业工人血铅和氧化应激酶变化的研究

目的研究职业性铅接触者的氧化损伤,探讨血铅和氧化应激酶之间的变化关系,以探讨铅中毒的作用机制。方法采用火焰原子吸收分光光度法测定空气中的铅含量,用石墨炉原子吸收分光光度法测定血铅浓度,选择超氧化物歧化酶（SOD）和丙二醛脱氢酶（MDA）作为氧化应激损伤的效应指标,分析血铅与氧化效应指标的变化。结果共采集了车间内5个工作点的空气样品。接触组血铅浓度（244．274±124．59）μg／L,显著高于对照组（P〈0．01）;接触组SOD活性（61．27±6．97）KU／L,与对照组比较无统计学差异（P〉0．05）;接触组MDA含量（9．42±3．89）mmol／L,显著高于对照组（P〈0．01）;血清MDA含量与血铅之间存在正相关关系（r=0．3,P〈0．01）;吸烟、饮酒对SOD活性和MDA含量影响无统计学差异。结论职业性铅接触引起人体血铅升高,作业场所空气中铅浓度与血铅含量变化不一致,血铅是近期铅接触者的敏感内接触指标,且血铅浓度越高,SOD活性代偿性升高;MDA含量越高,氧化损伤越明显。     

黄芪总黄酮抗紫外线损伤作用的实验研究

目的：探讨紫外线的细胞损伤作用和总黄酮的防护功效，方法：采用细胞溶血和细胞膜脂质过氧化反应体系研究了黄芪总黄酮的抗紫外线损伤作用，结果：黄芪总黄酮对紫外线所致红细胞溶血有很好的防护作用，在浓度为３０ｍｇ／Ｌ时，其防护率可达５０％；当浓度为１０ｍｇ／Ｌ，对紫外线所至细胞膜脂质过氧化反应即有明显的抑制作用（Ｐ〈０．０５），浓度达１００ｍｇ／Ｌ时，与对照组比较有显著的统计学差异（Ｐ〈０．００１），结论：     

二巯基丁二酸对大鼠铅性肾损害的保护作用

[目的]用亚急性铅性肾损害动物模型研究二巯基丁二凝(DMSA)对铅性肾损害的保护作用。[方法]按随机原则将72只SD大鼠分为对照组、染毒组、高防组和低防组，每组18只。对照组用蒸馏水灌胃，1h后，腹腔注射0．9％无菌生理盐水；染毒组动物用0．5％醋酸铅5mg／kg体重腹腔注射；高、低防护组动物先分别用150mg／kg体重和100mg／kg体重的DMSA灌胃，1h后，腹腔注射与染毒组等剂量的醋酸铅，每周5次，连续12周。[结果]染毒组自实验第3周开始肾铅、尿蛋白、尿γ—GT活性极显著地高于对照组及高、低防护组(P＜0．01)，且肾近曲小管上皮细胞水变性及细胞内线粒体出现丢失。防护组尿铅排泄量明显高于染毒组，肾铅、尿蛋白、尿γ—GT活性等权显著地低于染毒组(P＜0．01)。而且肾近曲小管上皮细胞水变性及细胞内线粒体丢失程度较染毒组明显减轻。[结论]大鼠腹腔注射0．5％醋酸铅(5mg／kg体重)可诱发铅性肾损害。DMSA对铅性肾损害有一定的保护作用，而且高剂量(150mg／kg体重)的DMSA保护效果优于低剂量(100mg／kg体重。在一般防护措施不奏效时，可作为辅助性预防用药物。     

氯化钇对人表皮细胞生长及凋亡的影响

目的：探讨稀土化合物氯化钇（YCl3）对人表皮细胞生长及凋亡的影响。方法：在无血清培养条件下，用MTT法检测人表皮细胞增殖功能。采用Tunel检测紫外线照射后人表皮细胞凋亡。结果：YCl3＜1．0mmol/L时对人表皮细胞生长无明显抑制作用（P＞0．05），而YCl3＞2．0mmol/L时对人表皮细胞生长有明显抑制作用（P＜0．01）。低浓度YCl3(0.1mmol/L）对紫外线诱导的人表皮细胞凋亡有抑制作用（P＜0．05），而高于0．5mmol/L YCl3对此外线诱导的人表皮凋亡无明显影响（P＞0．05）。结论：低浓度的YCl3对表皮细胞生长无影响，对此外线诱导的表皮细胞凋亡有一定的保护作用。     

铅镉联合作用对大鼠肾小管上皮细胞脂质过氧化的影响

为观察铅镉联合作用对大鼠肾小管上皮细胞脂质过氧化的影响 ,对原代大鼠肾小管上皮细胞提取、纯化、鉴定、培养后 ,采用 3× 3析因设计方法进行染毒实验 ,A组 :醋酸铅 0 0 2mmol L ;B组 :醋酸铅 0 1mmol L ;C组 :氯化镉 0 0 0 1mmol L ;D组 :氯化镉 0 0 0 4mmol L ;E组 :醋酸铅 0 0 2mmol L +氯化镉 0 0 0 1mmol L ;F组 :醋酸铅 0 0 2mmol L +氯化镉 0 0 0 4mmol L ;G组 :醋酸铅 0 1mmol L +氯化镉 0 0 0 1mmol L ;H组 :醋酸铅0 1mmol L +氯化镉 0 0 0 4mmol L。染毒时间为 6小时。经超声波粉碎细胞后 ,测定细胞内谷胱甘肽 (GSH)和丙二醛 (MDA)的含量 ,以及谷胱甘肽过氧化物酶 (GSH Px)和超氧化物歧化酶 (SOD)的活性。与对照组比较 ,联合染毒组GSH、GSH Px、SOD水平显著降低 ,MDA水平显著升高 ,析因分析表明 ,铅镉联合作用在对大鼠肾小管上皮细胞GSH、SOD、MDA改变方面有交互作用 (P <0 0 5 ) ,即铅镉联合作用呈现增毒作用 ;在对GSH Px改变方面未见交互作用     

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.