大庆龙凤湿地野禽卵内Se与GSH-Px的分布与关系

<正>微量元素硒(Se)与动物健康和疾病密切相关,缺硒会引发多种疾病,适量补硒能防治肿瘤、心血管病和一些地方病如克山病、大骨节病等[1]。硒是谷胱甘肽过氧化物酶(GSH-Px)酶系活性中心的必需成分,GSH-Px家族是动物体内不可缺少的一类抗氧化酶。     

补硒治疗重症全身性炎症反应综合征21例临床疗效分析

全身性炎症反应综合征 (ＳＩＲＳ)仍然是重病患者发病率和死亡率高的一个主要原因[1,2 ] 。患ＳＩＲＳ时 ,一系列代谢路径 (包括环氧酶路径和脂氧酶路径 )被激活 ,释放自由基。其结果不仅使受感染的脏器遭到损害 ,而且也破坏身体的细胞膜和其他细胞成分 ,导致高毒性的脂质过氧化物产生 ,这些物质是败血症进一步恶化的主要原因。自由基的主要清除系统是依赖硒的谷胱甘肽过氧化物酶[3 ] ,该酶具有能抵抗损害细胞膜的脂质过氧化物的作用 ,而各种严重疾病患者血浆中的硒浓度和谷胱甘肽过氧化物酶活性比正常人低。现已证明补硒可改善免疫细胞的一…     

硒螺旋藻拮抗大鼠肝纤维化的作用及机制研究

目的:研究硒螺旋藻(Se enriched Spirulina platensis,Se-SP)拮抗大鼠肝纤维化效应,以及对肝细胞增殖和谷胱甘肽过氧化物酶(GSH-Px)和硫氧还蛋白还原酶(TR)活性的上调作用。方法:在SD大鼠用硫代乙酰胺诱导肝纤维化模型,同期补充Se-SP,取肝进行组织病理分析,检测肝组织脂质过氧化产物丙二醛(MDA)含量及GSH-Px和TR活性,免疫组化方法测定肝细胞增生细胞核抗原(PCNA),放射免疫法测定肝细胞3H-TDR掺入水平。结果:Se-SP可明显减轻鼠肝组织纤维化程度,比亚硒酸钠更明显地促进肝细胞硒酶活性和细胞增殖,同时可抑制肝组织胶原的生成和血清透明质酸(HA)含量。结论:Se-SP对肝纤维化具有较强的抗氧化和促肝细胞再生及功能修复作用,其机制主要是Se-SP作为高生物利用度的补硒剂,通过上调硒酶活性,发挥直接或间接的生物效用。     

大剂量硒降低硒酶基因表达并致大鼠肝组织损伤

目的 :　探讨补充大剂量硒对谷胱甘肽过氧化物酶和硫氧还蛋白还原酶基因表达和酶活性的影响、以及对大鼠肝组织的作用。方法 :　给大鼠腹腔分别注射 0 ,2 0 ,40和 80 μg/ (kg·d)亚硒酸钠 -生理盐水 1 5d,取肝脏做组织切片 ,再将肝组织匀浆后通过反转录聚合酶链式反应半定量检测不同剂量亚硒酸钠对硒酶基因表达的影响 ,同时测定硒酶活性、肝组织硒含量及丙二醛含量。结果 :　补充亚硒酸钠 2 0 μg/ (kg· d)的鼠肝中 ,两类硒酶的 m RNA丰度及酶活性均增高 ,而补充 40和 80 μg/ (kg· d)亚硒酸钠的大鼠 ,两类硒酶的 m RNA丰度及酶活性均显著下降 (P<0 .0 5) ,且随补硒剂量升高下降幅度增大。而鼠肝硒含量则随补硒剂量升高而显著性增大 (P<0 .0 5)。与对照组相比 ,补充 40μg / (kg· d)亚硒酸钠的鼠肝脂质过氧化水平增高 (P<0 .0 1 ) ,肝组织在形态学上发生病变。结论 :　大剂量补硒降低鼠肝谷胱甘肽过氧化物酶和硫氧还蛋白还原酶基因表达和酶活性 ,并造成肝组织损伤。该作用与过量硒致组织脂质过氧化水平升高相关联     

连续流动氢化物发生原子荧光光谱法测定保健品中的硒

硒是人体必需的微量元素之一 ,具有独特的生物活性。近些年来 ,研究发现硒是人体重要含硒酶与硒蛋白必需的组成部分 ,其在人体内约有 1/ 3参与谷胱甘肽酶的合成 ,催化还原谷胱甘肽还原人体内有害的过氧化物—具有抗氧化的特性 ,并且在人体肌肉细胞的生物氧化过程中发挥电子传递作用[1] ;同时在人的肌体内参与许多重要代谢过程。补充硒可抑制肿瘤和心血管疾病的发生 ,提高人体免疫能力 ,但人体摄入过量硒会引起中毒。因此 ,建立硒的快速、准确测定方法具有重要意义。目前测硒的分析方法有比色法[2 ] 、电化学方法[3 ] 、气相色谱法[4] 、中子…     

硒与人体健康

联合国世界卫生组织于 1973年宣布 ,硒是人体生命中必需的、不可缺少的营养元素之一 [1 ] ,中国营养学会也将硒正式列为膳食谱中必需的营养元素 [2 ] 。硒是谷胱甘肽过氧化物酶的重要组成部分 ,该酶具有抗氧化作用 ,是重要的自由基洗洁剂 ,对细胞膜有保护作用。硒对有害重金属具有解毒功能 ,硒还有促进生长、保护视觉器官及抗肿瘤的作用。硒缺乏易引起克山病、大骨节病等地方病 ,硒对人体健康有着不可忽视的作用 ,与人体健康息息相关 [3,4 ] 。1　硒在人体内的吸收和排泄人体的消化道、呼吸道、皮肤、皮下肌肉或静脉都可以吸收硒 ,吸收的硒…     

富硒螺旋藻对大鼠实验性肝纤维化的拮抗效应

目的研究富硒螺旋藻(Se-SP)对大鼠肝纤维化的拮抗作用。方法SD大鼠腹腔注射3%硫代乙酰胺(TAA)溶液复制肝纤维化病理模型,每天灌胃分别补硒(10.8μg)、藻粉(100mg)和富硒藻粉(100mg,其中含硒10.8μg)进行实验干预。实验结束取大鼠血清进行常规肝功能检查,DAN荧光法测定硒(Se)含量,TBA法测定血清过氧化产物丙二醛(MDA)浓度,放射免疫法测定血清透明质酸(HA)水平,比色法检测谷胱甘肽过氧化物酶(GPx)和超氧化物歧化酶(SOD)活性。大鼠肝组织切片HE染色进行病理分析,Masson三色法胶原染色估计肝组织胶原相对含量(RCC%)。结果Se-SP组肝功能指标恢复最好,其血清中Se含量和GPx活性均明显提高(P<0.05),MDA和HA则明显降低(P<0.05)。肝纤维化病理诊断主要为Ⅰ级,肝组织RCC降低了约60%。进一步分析发现血清Se含量与GPx活性呈正相关(r=0.720),与MDA呈负相关(r=0.675)。结论Se-SP对大鼠实验性肝纤维化有较好的拮抗效应,作用机制与增强机体抗氧化水平和增加肝功能贮备有关。     

肝病与硒的关系

过去硒被认为是毒剂,50年代以后才被视为必需的微量元素,60年代以后,通过流行病学调查和动物实验始逐渐证实其抗癌作用。目前已知,硒是谷胱甘肽过氧化物酶(GSH-Px)的必需成分;而GSH-Px为肝内重要的抗氧化酶,能抑制过氧化反应,分解过氧化物,清除自由基,从而修复膜分子的损伤。因此,硒与肝病的关系日益受到重视。     

硒拮抗镉诱导大鼠组织脂质过氧化作用的影响

镉是一种重金属毒物 ,对机体可造成广泛的损害 ,腹腔注射一定剂量的镉可引起脂质过氧化反应[1] 。硒是必需微量元素 ,在正常摄入情况下具有抗脂质过氧化作用[2 ] 。但经饮水同时给予硒和镉 ,硒对镉所产生的脂质过氧化是否有拮抗作用的报道较少。为此我们给大鼠分别饮用镉 ,硒加镉水溶液 4周 ,并设空白对照组 ,研究肝、肾组织中谷胱甘肽过氧化物酶 (ＧＳＨ Ｐｘ)、超氧化物歧化酶 (ＳＯＤ)活性和丙二醛 (ＭＤＡ)含量的变化 ,以探讨硒对镉的拮抗作用 ,从而为镉的防治提供参考依据。1　材料与方法1 1　材料　ＳＤ成年大鼠 ,由广东省实验动物场…     

硒和谷胱甘肽过氧化物酶在癫痫病因中扮演重要角色

最近研究发现,氧化应激和氧自由基的产生既是癫痫发作的原因也是癫痫发作导致继发损伤的原因.鉴于硒和硒蛋白可对抗氧化损伤并提高神经细胞的存活,研究对比癫痫和正常儿童的血清硒水平及红细胞谷胱甘肽过氧化物酶活性.对照研究居住于同一地域处于同一年龄段的53个癫痫病儿童和57个正常儿童.血清硒水平和红细胞谷胱甘肽过氧化物酶活性分别用原子吸收分光光度仪和Gayman标准谷胱甘肽过氧化物酶检测盒来测定.结果显示,患者和正常个体血清硒水平分别为(72.90±22.20)μg/L和(86.00±15.00)μg/L.红细胞谷胱甘肽过氧化物酶活性数值在患者和正常人分别为(0.441±0.264)nmol/(min·L)和(0.801 0.267)nmol/(min·L).统计分析发现,患者硒和红细胞谷胱甘肽过氧化物酶水平较对照组显著降低.研究认为,患者血清硒和红细胞谷胱甘肽过氧化物酶活性较正常人低下,这一结果支持硒和谷胱甘肽过氧化物酶在癫痫病因中扮演重要角色这一观点.然而,红细胞谷胱甘肽过氧化物酶活性数值在硒缺乏个体并不能作为一个灵敏而特异指标来反映硒水平,所以研究者用硒检测来替代红细胞谷胱甘肽过氧化物酶活性测定.     

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 human drama of genetics: 'hard' and 'soft' media representations of inherited breast cancer

This paper examines media coverage of 'breast cancer genetics', and explores its implications for public understanding. We present a content analysis of coverage in British newspapers and look at a variety of popular forms, including women's magazines, television soap opera and radio drama. Genetic/inherited risk receives a great deal of coverage across a wide range of media formats and outlets. Much of this attention has focused on individuals from 'high risk families' and dilemmas around prophylactic mastectomies. Through examining media coverage, combined with interviews with media personnel and their sources, we show why this story proved so attractive to the media and highlight the different production values which influence coverage. Finally, we introduce preliminary findings from focus group discussions to demonstrate how such 'human interest' framing has engaged audience attention and influenced public understandings. The paper concludes by highlighting the implications for analysing, predicting, and engaging with, media representations of science.     

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.