天然抗氧化剂在人精液冷冻保存中的应用

精液的冷冻保存是辅助生殖技术的基础,但精液冻融过程会产生过多的活性氧自由基（ROS）,破坏精子的生理结构,使其质量下降,造成受精能力下降。目前,有些研究开始关注抗氧化剂在精液冷冻保存过程中的保护作用。其中一些来源于植物的天然抗氧化剂（如白藜芦醇、槲皮苷、染料木黄酮等）,这些物质的来源广泛,抗氧化能力非常高,而且毒性较低,可以有效抑制精子冻融后ROS的产生,减少精子在冷冻过程中受到的氧化损伤,从而保护精子的活力和遗传稳定性,可以作为冷冻保护剂的添加成份用于改良精子的冷冻保存。     

线粒体介导的活性氧与男性不育的相关研究进展

正自1943年Mac Leod首次提出活性氧(ROS)的产生可使精子迅速失去活力以来,氧自由基在男性生殖中的作用越来越受到人们的重视。近年来,国内外越来越多的研究发现,ROS不仅与精子高活跃性运动获能、顶体反应等生理功能有关,还与精子活力降低、DNA氧化损伤等病理作用有联系,ROS的产生可致使男性不育。本研究就ROS与男性不育的相关研究进展进行以下综述。1线粒体介导的ROS的产生     

活性氧与女性生殖

活性氧(reactive oxygen species,ROS)是正常有氧代谢的产物,正常情况下,ROS的产生和清除保持动态平衡,但是当线粒体功能下降,ROS产生增加或细胞抗氧化机制受损时,可造成ROS的累积,导致细胞氧化应激损伤.在腹膜液、卵泡液和输卵管积水等重要的生殖微环境内都检测到ROS的存在,并发现腹腔液内ROS水平与不明原因不孕相关,多种生殖组织内存在不同的氧化/抗氧化系统,ROS可能参与卵母细胞老化、胚胎体外发育不良以及一些不孕原因的形成,在女性生殖中起重要作用.     

氧化应激对男性（雄性）生殖系统的影响

氧化应激可产生活性氧簇（ROS）。正常状况下，低水平ROS具有调节细胞生理功能的作用，而异常高水平的ROS对组织和细胞产生相应的危害，如信号通路异常、能量代谢失调、基因突变和蛋白质结构改变等，进而影响细胞、组织、器官乃至系统的功能。男性（雄性）生殖系统中，高水平的ROS对生殖器官和生殖细胞同样产生严重的危害，如对睾丸的危害可影响其形态学结构及类固醇激素的合成；对生殖细胞可直接损伤精子的DNA、膜脂质和蛋白的结构，使精子的畸形率大幅度上升，最终导致男性（雄性）不育。综述男性（雄性）生殖系统ROS的产生及其对生殖的影响，对了解临床男性不育症的发病机制及治疗具有重要的意义。     

活性氧与女性生殖

活性氧(reactive oxygen species,ROS)是正常有氧代谢的产物,正常情况下,ROS的产生和清除保持动态平衡,但是当线粒体功能下降,ROS产生增加或细胞抗氧化机制受损时,可造成ROS的累积,导致细胞氧化应激损伤。在腹膜液、卵泡液和输卵管积水等重要的生殖微环境内都检测到ROS的存在,并发现腹腔液内ROS水平与不明原因不孕相关,多种生殖组织内存在不同的氧化/抗氧化系统,ROS可能参与卵母细胞老化、胚胎体外发育不良以及一些不孕原因的形成,在女性生殖中起重要作用。     

活性氧与女性生殖

活性氧(reactive oxygen species，ROS)是正常有氧代谢的产物，正常情况下，ROS的产生和清除保持动态平衡，但是当线粒体功能下降，ROS产生增加或细胞抗氧化机制受损时，可造成ROS的累积，导致细胞氧化应激损伤。在腹膜液、卵泡液和输卵管积水等重要的生殖微环境内都检测到ROS的存在，并发现腹腔液内ROS水平与不明原因不孕相关，多种生殖组织内存在不同的氧化／抗氧化系统，ROS可能参与卵母细胞老化、胚胎体外发育不良以及一些不孕原因的形成，在女性生殖中起重要作用。     

精子DNA完整性检测的临床应用

男性生育力受到许多因素的影响,其中精子DNA损伤一直是生殖医学领域研究的热点之一.精子线粒体、核DNA损伤会导致受精失败或影响受精后原核的形成、胚胎着床及子代的健康.目前,定量检测精子中异常DNA数量的方法有多种,虽然尚不理想,但各有其临床应用价值.精子DNA损伤分析比传统精液常规分析参数更稳定、更敏感.胞浆内单精子注...     

职业危害因素对男性生殖健康影响的研究进展

自1975年Lancranjan等[1]对职业铅暴露的男性工人生殖健康影响的研究开始,工作场所中职业危害因素与男性生殖健康的影响日益受到学者和全社会的普遍关注.Claman等[2]调查发现50年来西方男性的精子密度下降50％,提示男性生殖健康问题日益严重;Kenkel等[3]对Münster地区29个职业群体的不育男性精液参数研究也发现职业有害物质的暴露可导致男性不育.国内外对男性生殖健康影响的研究,主要集中在性功能障碍、精子的质量和数量、内分泌和子代影响等.许多研究表明,环境、职业和生活方式都会影响男性生殖健康,其中职业暴露是影响男性生殖健康的重要原因.     

氧化应激对辅助生殖技术的影响

氧化应激的发生源于反应性氧化物与生物抗氧化剂之间的平衡破坏,造成活性氧浓度升高,导致细胞氧化损伤。人类许多不同生殖状态下都存在氧化应激状态,尤其是辅助生殖技术(ART)过程中,体外操作不能模拟真实的体内生理条件,多种因素都可能导致氧化应激的产生及增加,其作用于精子、卵子、子宫内膜及胚胎等,影响胚胎着床,从而影响ART治疗结局,就ART过程中出现氧化应激状态的可能性及目前有效预防措施综述。     

氧化应激对辅助生殖技术的影响

氧化应激的发生源于反应性氧化物与生物抗氧化剂之间的平衡破坏，造成活性氧浓度升高，导致细胞氧化损伤。人类许多不同生殖状态下都存在氧化应激状态，尤其是辅助生殖技术（ART）过程中，体外操作不能模拟真实的体内生理条件，多种因素都可能导致氧化应激的产生及增加，其作用于精子、卵子、子宫内膜及胚胎等，影响胚胎着床，从而影响ART治疗结局，就ART过程中出现氧化应激状态的可能性及目前有效预防措施综述。     

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.