慢性镉中毒小鼠睾丸支持细胞及血-睾屏障超微结构观察和形态计量研究

用透射电镜观察并结合形态计量法研究慢性镉中毒时小鼠睾丸支持细胞及血－睾屏障的超微结构。结果表明：（１）支持细胞明显受损，细胞核增大，细胞器出现变性，有的支持细胞呈现坏死。（２）血－睾屏障各部分受损，间质内血管内皮细胞变性、坏死、剥脱；生精小管基膜增厚、分裂成层；管周组织内胶原原纤维显著增多；相邻支持细胞间紧密连接破坏。从形态结构方面考虑，认为血－睾屏障的瓦解可能是引发生精异常的主要原因。     

慢性镉中毒小鼠睾丸支持细胞及血—睾屏障超微结构观察和形…

用透射电镜观察并结合形态计量法研究慢性镉中毒对小鼠睾丸支持细胞及血－睾丸屏障的超微结构。结果表明：（１）支持细胞明显受损，细胞核增大，细胞器出现变性，有的支持呈现坏死。（２）血－睾屏障各部分受损，间质内血管内皮细胞变性，坏死，剥脱；生精小管基膜增厚，分裂成型；管周组织内胶原原纤维显著增多，相邻支持细胞间紧密连接破坏。从形态结构方面考虑，认为血－睾屏障的瓦解可能是引发生精异常的主要原因。     

激素及其受体调节Sertoli细胞功能的研究进展

Sertoli细胞是生精小管中唯一的体细胞，对生精过程发挥着重要作用。Sertoli细胞功能受多种激素调节，如卵泡刺激素（FSH）能调节其增殖及协助细胞间通讯（intercellular communication），且有助其形成血－睾屏障；雄激素能下调抗苗勒管激素（AMH）水平以促进Sertoli细胞发育，并维持血－睾屏障完整性；雌激素在不同剂量下可诱导Sertoli细胞凋亡与存活，并可调节水通道蛋白的表达而影响血－睾屏障等。综述各种激素及其受体对Sertoli细胞结构和功能的影响及阐明具体的分子机制，这对了解哺乳动物正常精子发生过程以及临床因精子发生障碍所致的男性不育症的治疗均有重要意义。     

激素及其受体调节Sertoli细胞功能的研究进展

Sertoli细胞是生精小管中唯一的体细胞,对生精过程发挥着重要作用。Sertoli细胞功能受多种激素调节,如卵泡刺激素(FSH)能调节其增殖及协助细胞间通讯(intercellular communication),且有助其形成血-睾屏障;雄激素能下调抗苗勒管激素(AMH)水平以促进Sertoli细胞发育,并维持血-睾屏障完整性;雌激素在不同剂量下可诱导Sertoli细胞凋亡与存活,并可调节水通道蛋白的表达而影响血-睾屏障等。综述各种激素及其受体对Sertoli细胞结构和功能的影响及阐明具体的分子机制,这对了解哺乳动物正常精子发生过程以及临床因精子发生障碍所致的男性不育症的治疗均有重要意义。     

BCG输精管内注射不是一种有效的男性避孕方法

Talwar等提出睾丸内输精管注射BCG(Bacille Calmette Guerin)可做为男性避孕的免疫方法之一。其原理为免疫细胞突破血睾屏障进入输精管及生精管,这些免疫细胞引起免疫反应,对抗生精细胞的减数分裂,并使生精细胞成为对体内其它细胞而言的免疫异己细胞。Talwar等报告此方法在哺乳动物如人、猴、猿等有效,且无副作用,此方法主要     

mTOR信号通路在哺乳动物睾丸中的作用

哺乳动物雷帕霉素靶蛋白（mammalian target of rapamycin,mTOR）是磷脂酰肌醇激酶相关激酶家族的一员,是一种高度保守的丝/苏氨酸蛋白激酶。其参与调节蛋白质合成、能量代谢和氧化应激等多项生理功能,在细胞增殖、生长、分化过程中起着中心调控的作用。近年许多研究证实在哺乳动物睾丸中mTOR信号通路可以促进支持细胞（sertoli cell）增殖与分化;mTOR信号通路不仅调控血-睾屏障（blood-testis barrier）的形成,而且mTORC1与 mTORC2分别调节血-睾屏障的开放与闭合;在精子发生（spermatogenesis）过程中,mTOR信号通路调控精原干细胞的增殖分化与自我更新,且调控着精母细胞的减数分裂。因此,mTOR信号通路在哺乳动物睾丸中具有重要的调控作用。综述mTOR信号通路在睾丸中对支持细胞增殖分化、血-睾屏障形成和精子发生的调控作用。     

睾丸支持细胞功能及调节

支持细胞与生精细胞构成睾丸曲细精管。支持细胞为生精细胞的分化成熟提供高浓度的睾酮和激素,脂类、维生素等多种营养物质,其所形成的血睾屏障使生精细胞受到良好的保护。支持细胞的功能受下丘脑-垂体-性腺轴的内分泌调节。其分泌的多种物质对其周围细胞及自身均有影响。睾丸内各种细胞间的局部调节——旁分泌及自分泌机制日益受到重视。     

睾丸支持细胞功能及调节

支持细胞与生精细胞构成睾丸曲细精管。支持细胞为生精细胞的分化成熟提供高浓度的睾酮和激素，脂类、维生素等多种营养物质，其所形成的血睾屏障使生精细胞受到良好的保护。支持细胞的功能受下丘脑－垂体－性腺轴的内分泌调节。其分泌的多种物质对其周围细胞及自身均有影响。睾丸内各种细胞间的局部调节－旁分泌及自分泌机制日益受到重视。     

高功率微波对大鼠血睾屏障通透性的影响及防护研究

目的探讨高功率雷达微波辐照对大鼠血睾屏障通透性的影响及防护研究。方法将成年雄性SD大鼠随机分为两大组（分别进行单次和连续微波辐照实验研究）。每大组又随机分为对照组、微波辐照组、药物防护组和物理防护组4个小组,每组10只。药物防护组大鼠在辐照前用安多霖药物灌胃。对微波辐照组、药物防护组和物理防护组大鼠进行辐照,其中物理防护组辐照盒外面套有防电磁波辐射面料。对照组大鼠行假辐照。辐照后取大鼠睾丸组织用含有硝酸镧颗粒的戊二醛固定液固定,用透射电镜观察血睾屏障通透性的变化。结果与对照组相比,辐照组的睾丸组织生精细胞间隙明显增大,发生不同程度的变性、线粒体空泡化,血睾屏障紧密连接处可见镧颗粒沉积,而在药物防护组和物理防服组,硝酸镧颗粒未穿过血睾屏障紧密连接。结论高功率雷达微波辐照能够使大鼠血睾屏障通透性显著增加,对机体产生一定程度的生殖毒性,安多霖胶囊和防电磁波辐射面料表现出了较好的防护效果。     

大鼠支持细胞和附睾细胞中雄激素结合蛋白(ABP)的免疫细胞化学定位

在雄激素和FSH影响下,支持细胞合成ABP。在成年,这种蛋白质的大部分分泌进入曲细精管,经过睾丸网转运到附睾。但最近证明,在血睾屏障形成之前,绝大部分ABP释放至血液内。性成熟后,由于支持细胞连接复合体的形成而限制了ABP从曲细精管逸出,但即便如此,于性成熟后血液中仍有ABP存在。迄今已有很多实验提示,血液中的ABP并不完全来自附睾。很可能ABP从支持细胞的基底部释放而进入血管和淋巴管的。如果这样,支持细胞以两种方向分泌ABP:即从其顶端分泌进入曲细精管腔;从其基底部分泌进入血管和淋巴     

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.     

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.     

The risk of heat exhaustion at a deep underground metalliferous mine in relation to surface temperatures

The risk of heat exhaustion at a deep underground metalliferous mine was assessed in relation to thermal conditions prevailing on the surface. For each day of a 1-year prospective case series of heat exhaustion, surface 24-h mean wet and dry bulb temperatures were recorded. From this data, 24-h mean wet bulb globe temperatures were derived using certain assumptions. The three surface temperature variables were significantly higher on those days on which heat exhaustion occurred, compared to those days on which it did not occur (P < 0.001). The relative risk of heat exhaustion on days when the 24-h mean wet bulb globe temperature was in the range 26.0-28.0 degrees C was 4.82 (95% confidence interval 2.12-10.96). Surface temperature data could be used at this mine to warn miners about the risk of heat exhaustion.     

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.