促肾上腺皮质激素释放因子对镉的淋巴细胞免疫毒性的体内外双向调节作用

目的 探讨体内外镉的免疫功能抑制过程中促肾上腺皮质激素释放因子（CRF）的修饰调节使用。方法 用垂体前叶细胞培养法测定中枢下丘脑和外周血浆CRF水平,用[^3H-TdR]掺入法分别检测体内、体外染毒的鼠脾T、B淋巴细胞增殖转化功能。结果 （1）整体实验动物各镉剂量组中枢下丘脑组织CRF水平均升高,有丝分裂原诱导脾T、B淋巴细胞增殖转化的刺激指数均低于对照组,差异有显著性（P＜0．05）;下丘脑CRF水平与T、B淋巴细胞增殖指数之间呈负相关关系（r＝－0．6750、－0．7560,P＜0．05）;外周血浆CRF水平各组间差异无显著性（P＜＞0．05。（2）体外染毒时,镉明显抑制大鼠脾淋巴细胞的增殖转化;1．0-100．0nmol/LCRF明显增强T、B淋巴细胞增殖转化能力;当以1．0nmol/LCRF与5－20μmol/L氯化镉联合作用对各实验组两种免疫组织[^3H-TdR]掺入率依然高于对照组,差异均有显著性（P＜0．05）。体内染镉时存在中枢组织CRF介导的免疫功能抑制性调节作用,但体外CRF却能增强免疫细胞活性并阻断镉对鼠脾淋巴细胞的直接免疫功能抑制。CRF对镉的淋巴细胞免疫毒性具有双向调节作用。     

海藻多糖对γ射线照射小鼠免疫功能的影响

目的：观察海藻多糖对辐射损伤小鼠免疫功能的影响。方法：测定小鼠胸腺细胞自发掺入^3H-TdR的能力、脾细胞对ConA（刀豆蛋白A）及LPS（脂多糖）的增殖反应及脾混合淋巴细胞反应，考察海藻多糖对γ射线照射小鼠免疫功能的影响。结果：海藻多糖处理组小鼠胸腺细胞自发反掺入^3H-TdR值、脾细胞对ConA及LPS的增殖反应、脾混合淋巴细胞反应均较照射组明显增强（P＜0．05），且与海藻多糖的剂量增加呈正相关。结论：海藻多糖对辐射所致的免疫功能损伤有明显的保护作用。     

水环境镉对鲫鱼淋巴细胞DNA合成的影响

目的 探讨镉对鲫鱼淋巴细胞DNA合成的影响及其卫生学意义。方法 鲫鱼72尾随机分成12组，每组6尾。设2．5、5、10、20和40μg／L五个氯化镉染毒组，水环境暴露24h，另设一个阴性对照组；在10μg／L暴露条件下，设12、24、48、72和96h五个时间效应组，另设一个0时间对照组。各组在规定时间内心脏取血0．5ml，采用^3H-胸腺嘧啶核苷(^3H-TdR)掺入法测定鲫鱼(Carassius auratus)淋巴细胞中^3H-TdR掺入量(DPM值)。结果 各氯化镉染毒组的DPM值明显降低，与阴性对照组比较，差异有显著性(P＜0.05，P＜0．01)；另外，随着镉浓度的增高，各剂量效应组的DPM值逐渐下降，在实验浓度范围内，存在剂量一效应关系(P＜0．01)。DPM值与作用时间无相关性。结论 镉可引起鲫鱼淋巴细胞DNA合成受抑，DNA合成可望作为水体污染生物检测指标之一。     

镉致成骨细胞增殖、分化及矿化损伤的预后效应

[目的]探讨镉染毒和染毒中止后成骨细胞增殖、分化及矿化等生物学功能的改变。[方法]采用混合酶消化法,分离sD大鼠颅盖骨成骨细胞,在5％CO2、37℃条件下培养24h后,持续镉染毒组以不同浓度的氯化镉（0～2．000μmol／L）持续染毒72h;间断镉染毒组以同样浓度的氯化镉染毒48h后,更换成无镉培养液继续培养24h,以噻唑蓝（MTT）法测定细胞增殖能力改变,用对硝基苯磷酸二钠盐（PNPP）偶氮法检测碱性磷酸酶（ALP）活性。同时,成骨细胞培养7d后,以0．500μmol／L氯化镉持续作用3—13d,然后分别停止作用10、8、6、0d,采用茜素红S进行矿化结节染色并计算面积以观察镉暴露中止后成骨细胞矿化能力损伤的恢复情况。[结果]氯化镉可明显抑制成骨细胞增殖、ALP活性及矿化能力。间断镉染毒组在停止作用24h后,成骨细胞的增殖、分化仍然明显低于对照组（P〈0．05）,与持续作用组比较没有明显改善。同样,间断镉染毒组在停止作用不同时间后,成骨细胞矿化结节数量和面积仍然明显低于对照组（P〈O．05）,与持续作用组相比没有明显恢复。[结论]镉暴露中止一定时间后,镉对成骨细胞的影响作用仍明显存在,表现为对成骨细胞增殖、分化及矿化能力的持续抑制。     

第二代天成金芝免疫功能调节的实验研究

目的：探讨第二代天成金芝的免疫功能调节作用。方法：选择小鼠脾淋巴细胞增殖反应、巨噬细胞吞噬功能及血清溶血素含量作为观察指标,以及反映机体细胞免疫、非特异性免疫和体液免疫水平。结果：第二代天成金芝剂量在30．0ml/kg时,能明显增强脾淋巴细胞的增殖能力、提高巨噬细胞的吞噬功能和血清溶血素水平,与对照组比较有显著差异（P＜0．05）。尤其是剂量在15．0ml/kg和30．0ml/kg时,巨噬细胞的吞噬率和吞噬指数都显著高于对照组（P＜0．05和P＜0．01）。结论：第二代天成金芝能明显的增强小鼠的免疫功能。     

镉对体外培养淋巴细胞免疫毒性的研究

目的探讨镉对人体T、B淋巴细胞的增殖、存活能力的影响,以明确镉的免疫毒性机制。方法采用尼龙纤维分离法分离T、B淋巴细胞,将分离的T、B淋巴细胞密度调整为2×106/ml,分为低、中、高浓度镉组(Cd,0.05,0.50,5.00 mmol/L)和对照组,在CO2培养箱中37℃培养12,24,48 h,用MTT法测定T淋巴细胞增殖功能,显微镜直接计数法观察淋巴细胞存活能力。结果镉致T淋巴细胞增殖功能MTT试验的吸光度(A)值明显下降。培养至48 h时,低、中和高浓度镉组的T淋巴细胞MTT试验的吸光度(A)值分别比对照组降低了6%,52%和85%。这些效应均呈剂量-反应关系。各浓度组镉均能直接抑制T、B淋巴细胞的存活率,使淋巴细胞计数明显下降,培养至48 h时,低、中和高浓度镉组的T淋巴细胞计数分别比对照组降低了24%,64%,98%,B淋巴细胞计数分别比对照组降低了19%,39%,80%。结论镉对体外培养人体T、B淋巴细胞的增殖、存活能力均能产生直接抑制作用。     

镉金属硫蛋白灌胃小鼠后镉的细胞分布及毒性

目的 探讨镉金属硫蛋白（CdMT)灌胃小鼠染毒后镉的细胞分布及淋巴细胞毒性。方法 应用分离纯化的CdMT灌胃染毒小鼠4周，检测血红细胞镉（RBC－Cd）和脾淋巴细胞镉（sLC-Cd)的含量，及脾T淋巴细胞增殖功能、T细胞亚群和DNA单链断裂（DNA－SSBs)。结果 RBC－Cd和 LC-Cd在CdMT染毒后明显增高；脾淋巴细胞毒性表现为增殖减低，T细胞亚群改变和DNA－SSBs尾长增加，且与细胞内镉含量有明显相关。结论 经消化道途径接触CdMT可致镉的吸收和在淋巴细胞内分布，导致DNA损伤和细胞免疫功能抑制。     

镉对小鼠淋巴细胞增殖功能、IL-2影响与cAMP的关系

目的：观察镉对小鼠脾T淋巴细胞增殖功能、cAMP(环磷酸腺苷)、IL-2(白细胞介素-2)等的影响，探讨它们在镉的免疫毒性中作用和关系。方法：对BALB／C小鼠体外、体内染镉后，测定脾T淋巴细胞增殖功能、IL-2活性、cAMP含量等。结果：体内、体外染镉均引起了小鼠脾T淋巴细胞增殖功能、IL-2水平有剂量一效应关系的降低，两者的变化呈正直线相关。体内染镉引起IL-2水平对数的降低与cAMP水平的升高呈负直线相关。体外染镉引起T淋巴细胞增殖功能、IL-2水平的降低与cAMP水平升高呈负直线相关。结论：镉有抑制小鼠脾T淋巴细胞IL-2活性的免疫毒性作用；IL-2在镉抑制T淋巴细胞增殖活性中有重要作用；cAMP信使系统可能参与介导了镉对脾T淋巴细胞增殖功能、IL-2.     

琼枝麒麟菜多糖对γ射线照射小鼠胸腺细胞周期及细胞增殖的影响

目的探讨γ射线对小鼠胸腺细胞周期及细胞增殖的影响,从细胞水平探讨琼枝麒麟菜多糖（EGP）的抗辐射作用.方法将小鼠随机分为正常对照组、模型组和3个不同剂量EGP实验组,灌胃10d后行一次性γ射线辐射,每只2Gy,20h后流式细胞仪检测胸腺细胞周期百分率,胸腺细胞自发增殖反应及脾细胞对ConA及LPS的增殖反应.结果小鼠经2Gyγ射线照射后,与正常对照组比较,G0/G1期脾细胞和胸腺细胞百分数明显增加（P＜0.01）,而S期和（M＋G2）期脾细胞、胸腺细胞百分数明显减少（P＜0.01）;与模型组比较,EGP实验组能使受照小鼠脾细胞和胸腺细胞S、G2＋M期的比例升高（P＜0.01）;EGP实验组小鼠胸腺细胞自发掺入3H-TdR值、脾细胞对ConA及LPS的增殖反应均较模型组明显增强（P＜0.05）.结论 EGP对辐射损伤细胞具有一定的保护作用.     

氯化镉的体外毒性及锌的拮抗作用

目的观察镉与锌体外对中国仓鼠肺成纤维细胞(V79)增殖的影响,初步探讨镉毒性机制。方法采用MTT法及3H-TdR掺入法,研究不同浓度氯化镉(CdCl2)单独或与生理浓度氯化锌(ZnCl2,10 μmol/L)同时染毒对V79细胞增殖的影响,并采用等离子体光谱仪测定细胞内Cd2 、Zn2 含量。结果 CdCl2对于V79细胞的增殖有抑制作用,且呈剂量依赖性.采用MTT法和3H-TdR掺入法所得CdCl2染毒24 h后50%抑制浓度(IC50)分别为13.73 μmol/L和13.60 μmol/L.随着CdCl2染毒浓度的增加,细胞内Cd2 含量也增加.而同时给予锌则对镉的增殖抑制效应在一定程度上具有明显的拮抗作用,锌可使细胞内Cd2 含量降低。结论在本实验条件下,CdCl2对V79细胞增殖具有抑制作用,锌对镉的毒性有拮抗作用。     

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.