铅对大鼠肾脏一氧化氮合酶、一氧化氮影响的研究

目的：探讨慢性染铅过程中大鼠肾脏一氧化氮合酶（NOS），一氧化氮（NO）的变化。方法：Wistar大鼠经饮水加0．0，18．4，184．0mg/L醋酸铅（PbAc)方法染毒，结果：高剂量组大鼠肾脏NOS活力30d后低于对照组（P＜0．05），低剂量染铅组大鼠肾脏NOS活力60d后低于对照组（P＜0．05），低剂量染铅组肾脏NO含量在各时间点上均有降低趋势，但差异无统计学意义（P＞0．05），高剂量组大鼠肾脏NO含量在60d,90d后低于对照组（P＜0．05），结论：铅可导致肾脏NOS活力降低，NO含量降低，可能是铅对肾脏产生细胞毒作用的机制。     

染铅大鼠骨髓NOs和NO的变化

目的 探讨染铅对大鼠骨髓一氧化氮合酶（NOS）活力、一氧化氮（NO）含量的影响及其与血铅相互关系。方法 Wistar大鼠经饮水（加0，18．4，184．0mg/L醋酸铅，分别供对照组、低剂量组、高剂量组自由饮用）染毒，测定骨髓NOS活力、NO含量。结果 NOS活力高剂量染铅组在7d、14d时均较对照组和低剂量组高（P＜0．05），其余时点各组间差异无显著性（P＞0．05），NO含量染铅高剂量组在7d、14d时均较对照组和低剂量组高（P＜0．05），60d各剂量组间差异无显著性（P＞0．05），90d高剂量组显著低于对照组（P＜0．05）。结论 染铅导致大鼠骨髓毒性，引起骨髓NOS活力、NO含量改变，表现为染铅早期骨髓NOS活力、NO含量升高，晚期骨髓NOS活力、NO含量降低；但慢性染铅对骨髓NOS活力、NO含量影响的生理机制有待进一步研究。     

染铅对大鼠脾脏NOS、NO、SOD、MDA的影响

目的 探讨染铅对大鼠脾脏一氧化氮合酶（NOS）活力、一氧化氮（NO）含量的影响及其与血铅相互关系。方法 Wistar大鼠经饮水（加0，18．4，184．0mg/L醋酸铅，分别供对照组、低剂量组、高剂量组自由饮用）染毒，测定脾脏NOS活力、NO含量、SOD活力、MDA含量。结果 NOS活力高剂量染铅组7d时显著低于对照组和低剂量组（P＜0．05），90d高于对照组和低剂量组（P＜0．05），低剂量组90d高于对照组（P＜0．05）；NO含量高剂量组和低剂量组60d、90d时均显著低于对照组（P＜0．05）；SOD活力高剂量组14d、30d、60d、90d时均低于对照组（P＜0．05），低剂量组30d、90d时显著低于对照组（P＜0．05）；MDA含量高剂量组14d、60d、90d时均显著高于对照组，60d时显著低于低剂量组，90d时显著高于低剂量组（P＜0．05），低剂量组在各时点与对照组比较，差异无显著性（P＞0．05）。血铅与脾脏NO含量呈倒S型剂量－效应曲线；血铅与脾脏SOD活力呈倒抛物线型剂量－效应曲线；血铅与脾脏MDA含量呈正抛物线型剂量－效应曲线。结论 铅可引起大鼠脾脏NOS活力、NO含量、SOD活力、MDA含量改变，表明铅可引起体内氧应激反应导致脂质过氧化损伤。     

铅对小鼠海马一氧化氮含量及合酶活性影响

目的探讨不同浓度铅对小鼠脑海码中一氧化氮合酶（NOS）活性和一氧化氮（NO）含量的影响。方法铅暴露组母鼠在小鼠出生第1d时，开始通过饮水饲以不同浓度醋酸铅：2．4，4．8，9．6mmol／L。分别在7，14，28，42d处死小鼠。测定NO含量和NOS活性。结果铅暴露组NOS活性为下降（14，28，42d）趋势。7d，铅暴褥组NOS活性均高于对照组，差异有统计学意义（P〈0．05），出生28d和42d时，4．8，9．6mmol／L铅暴露组NOS活性均低于对照组，差异有统计学意义（P〈0．05）。铅暴露组NO含量均比正常对照组小鼠相应期NO含量低。28，42d铅暴露组NO含量明显低于对照组。差异有统计学意义（P〈0．01）。结论铅暴露组小鼠脑海马NO含量和NOS活性变化可能是铅中毒的分子机制之一。     

天麻和阿胶联合对染铅大鼠海马一氧化氮含量及学习记忆的影响

目的 观察和探讨天麻和阿胶联合对染铅大鼠学习记忆损害的拮抗作用。方法 Wistar雄性大鼠经口染铅并分别单独及联合给予天麻（每天4.0g/kg)和阿胶（每天1.0g/kg)灌胃；每月用游泳试验测试学习记忆一次，3个月后处死大鼠，测定海马组织一氧化氮浓度。结果 在游泳试验中，高铅对照组和低铅对照组大鼠5min内到达平台次数，与空白组比较差异有非常显著性（P＜0．01）；天麻和阿胶单用即可明显增加染铅大鼠抵达平台的次数（P＜0．05，第2、3月P＜0．01），两者联用效果更为显著（P＜0．01）。海马组织一氧化氮测定，高铅对照组和低铅对照组海马一氧化氮，与空白组比较差异均有非常显著性（P＜0．01）；天麻单用即可明显提高染铅大鼠海马一氧化氮（P＜0．05，低铅时P＜0．01）；阿胶单用亦可明显提高染铅大鼠海马一氧化屡（P＜0．05）；天麻和阿胶联用效果更为显著（P＜0．01）。病理检查：高铅对照组和低铅对照组大鼠海马萎缩，细胞变性、坏死、轴突断裂、溶解、消失等，而高铅天麻阿胶组和低铅天麻阿胶组细胞变化不明显。结论 天麻和阿胶单用即可显著减轻铅对学习记忆的损害作用，两者联用效果更加显著。     

阿胶对染铅大鼠海马损害的拮抗作用

目的：观察和探讨阿胶对铅所致大鼠学习记忆损害的拮抗作用。方法：选用36只Wistar雄性大鼠随机分为对照组、铅组、阿胶铅组,每组12只。大鼠经口染铅并给予阿胶灌胃。每月用Y型迷宫试验测试学习记忆1次。3个月后处死大鼠,分别测定海马组织一氧化氮（NO）和总抗氧化能力（TAOC）并做病理检查。结果：（1）在Y型迷宫试验中,铅组大鼠学习记忆达标前所受电击次数（错误次数）显著高于对照组（P＜0．01）;阿胶铅组大鼠所受电击次数显著低于铅组（P＜0．05;2、3月P＜0．01）。（2）铅组大鼠海马NO和TAOC显著低于对照组（P＜0．01）,阿胶铅组大鼠海马NO和TAOC显著高于铅组（P＜0．05或P＜0．01）。（3）病理检查,铅组大鼠海马显著萎缩,细胞形态不规则、排列紊乱,细胞变性、脱失显著,轴突溶解、消失、阿胶铅组海马病理变化不明显。结论：铅可损害海马细胞结构和功能,降低海马组织NO和TAOC水平,降低学习记忆能力;阿胶对铅所海马损害和学习记忆障碍具有拮抗作用。     

多种营养素对染铅大鼠海马NOS和NO影响

目的探讨多种营养素联合拮抗铅对海马一氧化氮合成酶（NOS）活性和一氧化氮（NO）的作用,并寻找最佳具有拮抗作用的营养素组合。方法采用正交设计以染铅大鼠海马NOS和NO为检测指标,对酪氨酸、甘氨酸、蛋氨酸、牛磺酸、维生素C、维生素B1和锌等7种已知对铅毒性有拮抗作用和改善学习记忆功能的营养素进行筛选、配伍。结果给予营养素各组的血铅明显低于不给营养素的对照组（P〈0.01）,给予营养素各组的海马NOS活性和NO含量明显高于不给营养素的对照组（P〈0.01）。正交实验设计结果为蛋氨酸、锌和维生素B1降低血铅作用明显,给与不给的血铅值极差差异有统计学意义;锌增强大鼠海马NO含量作用明显,其极差差异有统计学意义（P〈0.01）;维生素B1不具有增强大鼠海马NOS活性和增加大鼠海马NO含量作用,给予维生素的各组均值小于不给予各组,其极差差异有统计学意义（P〈0.05）。结论多种营养素联合可改善铅对海马NOS和NO的作用,蛋氨酸、锌可降低血铅,提高海马中NOS活性,增加海马中NO含量的较好组合。     

天麻阿胶联合对染铅鼠脑一氧化氮及学习记忆的影响

目的：观察天麻和阿胶联合对染铅大鼠学习记忆损害的拮抗作用。方法：Wistar雄性大鼠经口和染铅并分别单独及联合给予天麻（4.0g.kg^-1.d^-1）和阿胶（1．0g.kg^-1.d^-1）灌胃，连续3个月，每月用游泳试验（水中寻找平台试验）测试学习记忆1次，最后处死大鼠测定小脑组织一氧化氮含量。结果：在游泳试验中，高铅对照组和低铅对照组大鼠15次中直线到达平台次数，与空白组比较差异均非常显（P＜0．01）。天麻单用即可显增加染铅大鼠直线到达平台的次数（第1月P＜0．05，第2，3月P＜0．01）；阿胶单用亦可显增加染铅大鼠在游泳试验中直线到达平台次数（P＜0．05）；天麻和阿胶联用更能显增加染铅大鼠在游泳试验中直线到达平台次数，与二单用相比差异非常显（P＜0．01）。小脑组织一氧化氮测定：高铅对照组和低铅对照组大鼠小脑一氧化氮，与空白组比较差异均非常显（P＜0．01）；天麻单用即可显提高染铅大鼠小脑一氧化氮（P＜0．05，低铅时P＜0．01）；阿胶单用也可显提高染铅大鼠小脑一氧化氮（P＜0．05）；天麻和阿胶联用更能显提高染铅大鼠小脑一氧化氮含量，与二单用相比差异非常显（P＜0．01）。结论：天麻和阿胶单用即可显减轻铅对学习记忆的损害作用，二联用效果更为显。     

染铅对大鼠端脑皮质4种生化指标的影响

为研究染铅对大鼠端脑皮质一氧化氮 (NO)、一氧化氮合酶 (NOS)、超氧化物歧化酶 (SOD)、丙二醛(MDA)的影响 ,进一步探明铅的神经毒作用机理。选择Wistar大鼠采用饮水加 0、18 4、184mg L醋酸铅法染毒。结果显示 :与对照组相比 ,低、高剂量组染铅 7d时NOS活力明显升高 (P <0 0 5 )。低剂量组 90d、高剂量组 30d后NOS活力均显著下降 (P <0 0 5 )。 90d时低剂量组NO含量显著低于对照组 (P <0 0 5 ) ,高剂量组NO含量在 14、6 0、90d均显著低于对照组 (P <0 0 5 )。染铅组皮质SOD活力在 30d后明显低于对照组 (P <0 0 5 ) ,高剂量组 30d时皮质SOD活力也较低剂量组低 (P <0 0 5 )。低剂量组皮质MDA含量在 30d后显著升高与对照组比 (P <0 0 5 ) ,高剂量组皮质MDA含量在 14d后显著升高 (P <0 0 5 ) ,且在 14d、90d时 ,高剂量组显著高于低剂量组 (P <0 0 5 )。提示铅所致神经毒性 ,可能与铅引起端脑皮质NO含量、NOS活力、SOD活力、MDA含量改变有关     

高糖、高胰岛素与糖尿病血管并发症的关系

目的 探讨高糖血症、高胰岛素血症对ET－1缩血管作用的影响及机制。方法 复制大鼠高糖血症模型,观察高糖组和对照组大鼠的主动脉血管环在40mIU／L胰岛素中对10^-9mol/L ET－1的反应;测定血浆NO2^-含量和血管壁一氧化氮合酶（NOS）的活性。结果 高糖大鼠对ET－1的缩血管反应明显强于对照组（P＜0．05）;高糖组NO2^-含量和tNOS活性明显低于对照组,其中以cNOS降低为主（P＜0．01）。结论 长期高糖血症通过损伤血管内皮功能使NO合成减少,血管对活性物质ET－1的反应性增强、血管张力增加,此机制可能参与了动脉粥样硬化等血管并发症的发病。     

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.