超短肠大鼠结肠代偿的细胞超微结构变化

目的 观察超短肠大鼠结肠黏膜细胞超微结构和吸收功能的变化.方法 将30只雄性SD大鼠随机分为超短肠组（手术切除大鼠90%～95%的小肠）、假手术组和正常对照组,每组10只.给予肠内营养支持21 d后,采用扫描电镜观察结肠黏膜表画形态,透射电镜观察结肠黏膜上皮细胞超微结构变化.用D-木糖溶液和15N-甘氨酸对结肠进行封闭式连续循环灌注3 h,测定结肠对水、碳水化合物、氨基酸的吸收情况.结果 透视电镜观察结果显示,超短肠组大鼠较正常大鼠的结肠黏膜杯状细胞减少,吸收上皮细胞增多,微绒毛变长变密,细胞膜表面积增加,细胞间连接明显增多,桥粒、紧密连接和缝隙连接较多,内质网和高尔基体发达,线粒体数量明显增多.扫描电镜观察结果显示,超短肠组大鼠较正常大鼠的结肠皱襞深度增加,黏膜增厚,隐凹开口明显增多;隐凹内微绒毛样结构数目明显增多,长度增长且密度增加.超短肠组大鼠结肠对水的吸收能力明显高于假手术组和正常对照组（P均=0.000）;1、2、3 h内木糖吸收率和15N-甘氨酸吸收率均明显高于假手术组和正常对照组（P均＜0.01）.结论 超短肠大鼠结肠吸收能力可代偿增强.结肠黏膜细胞凋亡减少、吸收细胞增多、微绒毛增生、细胞膜表面积增加和线粒体增多可能是其物质和能量基础.     

运用蛋白质组学技术研究晕船适应大鼠脑干蛋白的表达变化

目的应用蛋白质组学技术,建立晕船适应及不适应大鼠脑干蛋白质双向电泳图谱,鉴定差异表达蛋白。方法应用双向电泳技术,对2组40只大鼠脑干蛋白进行分离,肽指纹图谱鉴定差异蛋白质,并观察谷氨酰胺合成酶活力变化。结果获得8个晕船适应相关蛋白质,其中硫氧还蛋白过氧化物酶Ⅱ、低相对分子质量神经丝蛋白、泛素羧基末端水解酶PGP9.5和谷氨酰胺合成酶上调;碳酸酐酶Ⅱ、磷酸丙糖异构酶Ⅰ、磷酸甘油酸变位酶B和线粒体电压依赖型阴离子通道下调。谷氨酰胺合成酶在晕船适应组大鼠活力增强。结论大鼠对晕船适应后可诱导与能量代谢、神经递质和氧化应激相关的脑干蛋白质组的改变。     

中链三酰甘油对短肠综合征大鼠脂肪代谢和肠道代偿的影响

目的:研究肠内营养(EN)中添加中链三酰甘油(MCT)对广泛肠切除术后大鼠脂肪代谢和肠道代偿的影响.方法:体质量220～250 g SD大鼠27只,随机分为三组.假手术对照组(Con组)行空肠横断吻合,长链三酰甘油(LCT)短肠组(LSB组)和中、长链甘油三酯(MCT/LCT)短肠组(MSB组)均行85%中段小肠切除.各组大鼠于术后第2～14天,分别给予等氮和等热量的EN支持,其中Con组和LSB组EN的脂肪均为LCT,MSB组EN的脂肪含50% LCT和50%MCT.术后每天监测体质量变化;术后第12～14天检测脂肪吸收率;术后第15天处死动物,取血检测血浆总游离脂肪酸及必需脂肪酸水平,称量空肠及回肠重量、空肠及回肠黏膜重量,检测空肠及回肠黏膜DNA及蛋白质含量;行小肠病理检查,测量空肠及回肠黏膜绒毛高度、隐窝深度和黏膜厚度,并检测空肠和回肠黏膜增殖细胞核抗原(PCNA)和细胞凋亡情况.结果:大鼠广泛肠切除术后出现明显的肠道代偿.MSB组的脂肪吸收率、血清总游离脂肪酸及必需脂肪酸水平显著高于LSB组;MSB组在体质量、肠黏膜重量、肠黏膜DNA及蛋白质含量、肠黏膜病理(绒毛高度、隐窝深度和黏膜厚度)、肠黏膜细胞增殖及凋亡与LSB组比均无显著性差异.结论:添加50% MCT的EN较单纯LCT的EN更能增加短肠综合征大鼠对脂肪的吸收,增加血清游离脂肪酸水平,而不影响肠道代偿.     

谷氨酰胺对短肠综合征大鼠残留小肠、结肠形态的影响

目的：观察谷氨酰胺（Gln)对短肠综合征大鼠残留小肠、结肠形态的影响。方法：23只雄性SD大鼠切除80%小肠,随机分为三组：饮食组（n=8)大鼠术后自由进食;全胃肠外营养（TPN）组（n=8)输TPN标准液;Gln组（n=7）输TPN Gln液;正常大鼠8只,作为正常对照组。术后第7天,称体重,取残留空肠、回肠、结肠进行组织学检查（包括光镜和电镜）。结果：饮食组和Gln组术前体重无明显差异,但术后体重有明显差异;饮食组空肠粘膜绒毛高度（VH）和粘膜厚度（MT）、回肠粘膜的VH均明显大于正常组;TPN组空肠粘膜VH、MT明显小于正常组;回肠粘膜隐窝浓度（CD）、MT亦明显小于正常组;Gln组空肠和回肠粘膜VH、CD和MT明显大于TPN组;饮食组结肠MT明显大于正常组,Gln组结肠MT明显大于TPN组。结论：80%小肠切除后,残留小肠发生代偿性改变,食物刺激是残留小肠代偿的重要因素;但这种代偿不完全,TPN可维持机体体重,但可引起残留小肠粘膜萎缩;Gln能阻止TPN引起残留小肠粘膜萎缩,促进残留小肠代偿;同时Gln还促结肠粘膜增生。     

大鼠小肠缺血-再灌注损伤后隐窝细胞增殖在肠黏膜屏障损伤修复中的作用

目的:探讨大鼠肠道缺血-再灌注(I-R)损伤后肠道隐窝细胞的增殖特征及其在肠黏膜屏障损伤修复中的作用。方法:选50只大鼠,随机分为对照组(n=5)和I-R组(缺血30 min),其中I-R组根据再灌注(R)0、0.5、1、2、4、6、12、24和48 h再分为9组,每组5只。观察各组大鼠小肠组织的病理学改变。用免疫组化法检测小肠隐窝细胞的增殖程度(Ki67,Musashi-1)。用蛋白质印迹法检测小肠黏膜组织中紧密连接蛋白ZO-1和Oc-cludin的表达。用ELISA法检测血清中D-乳酸和IL-6浓度。从回肠灌注FITC-Dextran-4溶液后,用荧光分光光度法测算其在血清中的浓度。结果:与对照组比,I/R组在R 0～1 h时出现明显的肠黏膜结构损害,渗透性增高,炎性反应增强,黏膜屏障损伤。R 1～2 h时隐窝细胞增殖明显,肠黏膜屏障功能开始修复。R 2 h时肠道渗透性显著降低,紧密连接蛋白表达开始恢复。至R 12～24 h时肠黏膜损伤基本恢复。结论:肠道I-R损伤后,隐窝细胞的增殖在肠黏膜屏障修复中起着重要作用。     

酪酪肽对全肠内营养支持小鼠残留小肠代偿的影响

目的:通过建立广泛小肠切除(mSBR)的酪酪肽(PYY)基因敲除(Pyy-/-)小鼠模型,研究早期在TEN支持下PYY对残留小肠的代偿作用.方法:将30只Pyy-/-小鼠分为三组,每组10只.假手术(Sham)组仅横断小肠但不切除小肠;广泛小肠切除(mSBR)组切除50%小肠,保留近段空肠约1cm,远段回肠9ca;广泛小肠切除加PYY(mSBR-PYY)组切除50%小肠,皮内注射PYY1～36.所有小鼠术后2～7d均接受TEN.观察各组小鼠术后回肠黏膜的DNA和蛋白质含量、绒毛高度和隐窝深度、回肠隐窝细胞的增殖指数和绒毛上皮细胞的凋亡指数.结果:mSBR组小鼠同肠黏膜的DNA和蛋白质含量、绒毛高度、隐窝深度、回肠隐窝细胞的增殖指数和绒毛上皮细胞的凋亡指数,显著高于Sham组.mSBR-PYY组小鼠回肠黏膜的DNA和蛋白质含量、绒毛高度和隐窝深度,显著高于mSBR组;回肠隐窝细胞的增殖指数显著高于mSBR组;回肠绒毛上皮细胞的凋亡指数显著低于mSBR组.结论:在早期TEN支持下,PYY不仅能促进mSBR小鼠肠黏膜细胞的增殖,而且还能抑制其凋亡,在残留小肠的代偿中起重要作用.     

盐酸右美托咪定调节重症急性胰腺炎大鼠自主神经功能对肠黏膜屏障的影响

目的:探讨盐酸右美托咪定(Dex)对重症急性胰腺炎(SAP)大鼠自主神经活性和肠黏膜屏障的可能作用. 方法:将24只大鼠随机分为对照组、SAP组和Dex组.对照组为假手术组,SAP组通过胰胆管逆行注射牛磺胆酸钠建立SAP模型,Dex组在建立SAP模型后持续静脉输注Dex注射液.持续监测大鼠心率变异性(HRV),观察自主神经功能的变化.用蛋白质印迹法检测小肠黏膜组织紧密连接蛋白Occludin和ZO-1的表达.用ELISA法检测肠黏膜炎性因子TNF-α和IL-6的表达.在造模后4、8和12 h抽血,用ELISA法检测血清肠脂肪酸结合蛋白(iFABP)变化.通过肠黏膜组织髓过氧化物酶(MPO)活性评估肠道中性粒细胞活性,通过丙二醛(MDA)水平评估肠道脂质氧化应激水平. 结果:SAP组大鼠HRV明显降低,Dex组大鼠HRV明显高于SAP组.Dex能降低SAP大鼠肠黏膜炎性因子、MPO和MDA水平,上调紧密连接蛋白ZO-1的表达.并且,Dex组大鼠血清iFABP水平明显低于SAP组. 结论:Dex能降低SAP大鼠交感神经活性,减轻肠黏膜损伤.     

胰岛素对短肠综合征大鼠蛋白质代谢及肠功能代偿的影响

目的:采用短肠综合征(SBS)大鼠的TEN模型,研究胰岛素(INS)对蛋白质代谢的影响及其残存肠管的代偿作用. 方法: 将30只大鼠随机分为三组,每组10只.假手术(Sham)组、短肠(SBS)组和短肠 胰岛素(SBS-INS)组.Sham组大鼠仅切断吻合小肠;SBS组切除85%小肠;SBS-INS组切除85%以上小肠并皮内注射速效胰岛素制剂.各组大鼠术后均行TEN支持.观察大鼠术后的一般情况、营养状况、氮平衡、残存肠黏膜DNA和蛋白质含量、肠绒毛高度、肠隐窝深度和隐窝细胞的增殖指数. 结果:SBS-INS组大鼠术后第12～14天体质量显著高于SBS组,术后第5～14天,氮平衡亦显著优于SBS组;SBS-INS组大鼠的营养指标、肠黏膜DNA和蛋白质含量、肠绒毛高度、肠隐窝深度和隐窝细胞的增殖指数,显著高于SBS组. 结论:胰岛素能促进EN支持的SBS大鼠蛋白质合成及残存肠管的代偿,从而增加肠道的吸收面积,改善营养状况.     

酪酪肽促进小鼠残留肠上皮细胞增殖的信号转导途径

目的: 采用酪酪肽(PYY)基因敲除(Pyy-/-)小鼠,研究PYY促进肠上皮细胞增殖的主要细胞信号转导途径,建立小肠广泛切除的小鼠模型. 方法:将24只成年雄性Pyy-/-小鼠分为三组,每组8只.假手术(Sham)组仅横断小肠但不切除小肠;广泛小肠切除(SBR)组切除50%小肠,保留近段空肠约1 cm,远段回肠9 cm;小肠广泛切除加PYY(SBR-PYY)组切除50%小肠,并于术后36 h皮内注射PYY1～36.各组小鼠均于给药后2 h处死,并取回肠组织,观察隐窝细胞的增殖指数、肠黏膜Y1受体的mRNA表达以及肠黏膜细胞膜蛋白激酶C-ε(PKC-ε)和磷酸化的细胞外信号调节蛋白激酶(p44/42 MAPK)的蛋白质表达情况. 结果:SBR组小鼠回肠隐窝细胞的增殖指数和肠黏膜磷酸化的p44/42 MAPK的蛋白质表达量显著高于Sham组,SBR-PYY组小鼠显著高于SBR组;SBR组小鼠回肠黏膜Y1受体mRNA的表达量和细胞膜PKC-ε的蛋白质表达量与Sham组无明显差异,SBR-PYY组小鼠显著高于SBR组和Sham组. 结论:PYY结合Y1受体后可通过细胞膜的PKC-ε和细胞质的p44/42 MAPK磷酸化来促进小肠广泛切除后残留肠上皮细胞的增殖.     

腹腔暴露对大鼠肠黏膜屏障的影响

目的:观察腹腔暴露对大鼠肠黏膜屏障的影响。方法:将30只大鼠随机分为五组,即对照组、假手术组、腹腔暴露1 h组、腹腔暴露2 h组和腹腔暴露3 h组,每组6只。腹腔暴露组大鼠剖腹后暴露腹腔,但不进行任何手术操作,暴露相应时间后关腹。假手术组大鼠仅作腹壁切口,不打开腹腔。对照组大鼠仅作相应的麻醉。术后24 h,取血检测血清D-乳酸水平,并取回肠组织测定肠道FD4清除率、小肠黏膜紧密连接蛋白ZO-1和Occludin的表达水平,同时观察小肠组织的病理变化。结果:腹腔暴露组较对照组大鼠血清D-乳酸水平有所上升,肠道FD4清除率有所增加,小肠黏膜紧密连接蛋白ZO-1和Occludin的表达水平均有所下降,小肠黏膜病理形态有所改变,并且这种差异随腹腔暴露时间的延长而逐渐显著。Pearson相关性检验分析表明,腹腔暴露组大鼠血清D-乳酸水平和肠道FD4清除率与肠黏膜损伤Chiu's评分均呈显著的正相关。结论:腹腔暴露大鼠肠黏膜屏障功能受损,并随着腹腔暴露时间的延长而逐渐加重。     

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.