胆红素拮抗间二硝基苯致大鼠肝细胞DNA氧化损伤作用

[目的]探讨胆红素拮抗间二硝基苯(m-DNB)诱导大鼠肝细胞DNA氧化损伤作用。[方法]原代培养大鼠肝细胞与不同剂量m-DNB孵育,细胞色素C还原法和电子顺磁自旋捕获法观察m-DNB染毒大鼠肝细胞超氧阴离子自由基()和羟自由基(OH?)生成;以单细胞凝胶电泳和氚胸腺嘧啶(3H-TdR)掺入法分别观察m-DNB对大鼠肝细胞DNA损伤和合成抑制情况,分析胆红素干预对以上情况的影响。[结果]随m-DNB剂量增加,大鼠肝细胞和OH?水平、DNA受损细胞数和细胞DNA断裂程度增加,3H-TdR掺入量下降,具有较明显的剂量-反应关系(P<0.01)。10μmol/L胆红素干预可明显减低m-DNB致大鼠肝细胞和OH?水平、降低DNA受损细胞数和细胞DNA断裂程度、拮抗m-DNB对大鼠肝细胞DNA合成的抑制(P<0.01)。[结论]胆红素可拮抗m-DNB诱导大鼠肝细胞活性氧导致的DNA氧化损伤、减轻m-DNB对大鼠肝细胞DNA合成的抑制作用。     

槲皮素对大鼠肝细胞谷胱甘肽水平及其相关代谢酶活性的影响

目的研究槲皮素对大鼠肝细胞谷胱甘肽水平及其相关代谢酶活性的影响方法不同浓度槲皮素干预大鼠肝细胞后,采用MTT法检测细胞活力;使用流式细胞仪检测细胞凋亡率;采用试剂盒检测细胞培养液中丙氨酸氨基转移酶(ALT)、天冬氨酸氨基转移酶(AST)活性,以及大鼠肝细胞中谷胱甘肽过氧化物酶(GSH-Px)、谷胱甘肽硫转移酶(GST)、谷胱甘肽还原酶(GR)和γ-谷氨酰基半胱氨酸连接酶(γ-GCL)活性;高效液相色谱法测定大鼠肝细胞中还原型谷胱甘肽(GSH)、氧化型谷胱甘肽(GSSG)含量结果与对照组相比,30μmol/L以上剂量的槲皮素干预组细胞活性显著降低,凋亡率无明显变化。20μmol/L槲皮素干预大鼠肝细胞24h后,细胞GSH含量、GST和γ-GCL活性显著升高,GSH-Px活性显著降低。结论适宜浓度的槲皮素能够提高GST活性,并能通过提高γ-GCL活性促进大鼠肝细胞GSH生成,从而提高谷胱甘肽抗氧化系统的抗氧化能力。     

槲皮素对大鼠原代肝细胞酒精性氧化损伤的防护作用

目的:观察槲皮素(quercetin)对大鼠原代肝细胞酒精性氧化损伤的防护作用。方法:经二步胶原酶技术分离培养大鼠原代肝细胞,用100mmol/L无水乙醇染毒细胞8h,作为酒精损伤模型。乙醇染毒前经不同剂量槲皮素(25～200μmol/L)预作用不同时间(0～8h),观察槲皮素干预对细胞培养上清液中乳酸脱氢酶(LDH)、谷草转氨酶(AST)活性,丙二醛(MDA)、谷胱甘肽(GSH)水平和超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性的影响。结果:大鼠原代肝细胞经100mmol/L酒精暴露8h后,LDH、AST活性,MDA、GSH含量和SOD、CAT活性与对照组相比,均有非常显著性差异;酒精暴露前1～4h经50～75μmol/L槲皮素干预效果最明显,LDH、AST、MDA和GSH、SOD、CAT水平分别较酒精组非常显著性降低和升高。结论:槲皮素可能通过减少GSH耗竭,提高抗氧化酶活性,抑制脂质过氧化来保护大鼠原代肝细胞抗酒精性氧化损伤,保护作用呈剂量与时间效应关系。     

槲皮素通过促进大鼠肝细胞转硫化途径降低同型半胱氨酸水平的研究

目的探讨槲皮素对大鼠肝细胞同型半胱氨酸(homocysteine,Hcy)代谢的影响。方法实验1:培养的大鼠肝细胞分成2组,对照组和5μmol/L槲皮素组,分别用DMEM培养液和含有5μmol/L槲皮素的DMEM培养液培养;实验2(治疗性模型):培养的细胞分成4组:对照组、5μmol/L槲皮素组、50mmol/L蛋氨酸(methionine,Met)组和5μmol/L槲皮素+50mmol/L Met组,分别用空白DMEM培养液,含有5μmol/L槲皮素、50mmol/L Met以及5μmol/L槲皮素+50mmol/L Met的DMEM培养液培养24h,随后收集培养液检测Hcy;实验3(预防性模型):培养的细胞分成4组:对照组、5μmol/L槲皮素组、50mmol/L Met组和5μmol/L槲皮素+50 mmol/L Met组。在前23h,5μmol/L槲皮素组、5μmol/L槲皮素+50mmol/L Met组用含有5μmol/L槲皮素的DMEM培养液处理,其余两组用空白培养液处理;在实验结束前的1h,所有组均换液,分别用空白培养液,含有5μmol/L槲皮素、50 mmol/L Met和5μmol/L槲皮素+50mmol/L Met的培养液处理细胞1h。实验结束,收集各组培养液和肝细胞,检测培养液Hcy水平,肝细胞内谷胱甘肽(GSH)含量以及胱硫醚-β合成酶(CBS)活性和表达。结果在槲皮素处理组,槲皮素和甲基化槲皮素的含量分别为(36.74±0.05)μg/L和(31.57±0.03)μg/L。在实验2和实验3中,Met处理后Hcy水平显著增加,在实验3中槲皮素处理能够降低Hcy水平。实验3中槲皮素组及其槲皮素+Met处理组GSH含量增加,CBS活性显著增加。结论在Met负载大鼠肝细胞,槲皮素能通过促进转硫化途径来降低Hcy水平。     

姜黄素对乙醇诱导的大鼠原代肝细胞损伤的防护作用

目的 研究姜黄素对乙醇诱导的大鼠原代肝细胞氧化损伤的防护作用.方法 以二步胶原酶技术分离的SD大鼠原代肝细胞经不同剂量(0～200mmol/L)和不同时间(0～24 h)暴露于乙醇,确定乙醇对肝细胞损伤的敏感的暴露时间与剂量.乙醇暴露前用姜黄素进行不同暴露剂量(0～50 μmol/L)和暴露时间(0～5 h)的预暴露.检测细胞培养上清液中天门冬氨酸氨基转移酶(AST)和乳酸脱氢酶(LDH)活力及肝细胞的氧化抗氧化指标[谷胱甘肽(GSH)、丙二醛(MDA)、超氧化物歧化酶(SOD)]来观察姜黄素对肝细胞免受乙醇氧化损伤的保护效应.结果 与对照组相比,乙醇暴露组随着乙醇暴露浓度的增加和时间的增长,肝细胞培养液上清液中的LDH、AST活力和MDA水平升高,GSH含量和SOD活力下降.以100mmol/L暴露8 h最为明显.与乙醇100mmol/L暴露8 h组相比,姜黄素预暴露组(0～50μmol/L)随姜黄素剂量的增加,LDH、AST活力下降(P＜0.05),姜黄素预暴露剂量为15和30 μmol/L时接近对照组水平;MDA生成明显减少(P＜0.05);但SOD、GSH水平明显升高(P＜0.05),姜黄素预暴露剂量为15和30 μmol/L时,SOD基本回复到对照组水平.15 μmol/L姜黄素预暴露1和5 h,各个指标与乙醇组相比,差异均有统计学意义,1 b干预效果优于5 h.结论 姜黄素可能通过降低GSH消耗,提高抗氧化酶活力,抑制脂质过氧化来保护大鼠原代肝细胞的酒精性氧化损伤,保护作用与姜黄素剂量及暴露时间有关.     

白藜芦醇诱导HO-1对酒精性肝细胞的保护作用

目的白藜芦醇(resveratrol)是非黄酮类的多酚化合物,具有多种有益的生物学效应。本研究目的观察白藜芦醇对酒精导致的人原代肝细胞损伤的保护作用及机制。方法经体外灌流、分离培养人原代肝细胞。测定白藜芦醇20μmol/L对酒精致肝细胞LDH释放率的影响。人原代肝细胞给予不同受试物(100 mmol/L酒精,20μmol/L白藜芦醇,25μmol/L Znpp9(锌原卟啉Ⅸ:zinc protoporphyrin-IX))24h,观察HO-1酶活性变化,孵育上清液AST,LDH释放水平,肝细胞内MDA,GSH含量变化。结果白藜芦醇可显著升高酒精致肝细胞LDH释放率的EC50(从700 mmol/L上升至1050 mmol/L);白藜芦醇可使肝细胞HO-1酶活性明显增加,并可显著抑制酒精导致的肝细胞AST,LDH释放,降低肝细胞内MDA水平,提高GSH含量。但是HO-1抑制剂Znpp9却明显降低了白藜芦醇对酒精导致的肝细胞损伤的保护作用。结论白藜芦醇对酒精导致的人肝细胞损伤具有保护作用,这种保护作用与其诱导的HO-1酶活性升高有关。     

富硒酵母对高脂饮食大鼠血脂和抗氧化指标的影响

目的研究富硒酵母对雄性高脂血症大鼠血脂水平的影响和抗氧化作用。方法喂养雄性SD大鼠高脂饲料建立高脂血症模型,将造模成功的大鼠随机分为含有硒剂量为0.83和8.33μg/kg的干预组、模型对照组,同时设空白对照组,干预60 d。模型对照组和空白对照组灌胃相等剂量的生理盐水。在干预的第20、40、60天,眼内眦采血(不禁食),测定总胆固醇(TC)、甘油三酯(TG)、高密度脂蛋白胆固醇(HDL-C)和低密度脂蛋白胆固醇(LDL-C)水平;并在实验干预第60天禁食12 h,眼内眦静脉丛取血,测血清中超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)及总抗氧化(T-AOC)水平。同组不同时期血脂水平采用重复测量数据的方差分析,同时期不同组血脂水平采取单因素方差分析和LSD-t检验。结果干预实验第20、40、60天,0.83μg/kg干预组血清TC、LDL-C、TG水平和8.33μg/kg干预组血清TG水平明显低于模型对照组,差异均有统计学意义(P0.05);在干预实验的第60天,8.33μg/kg干预组血清TC、LDL-C水平[分别为(3.06±0.38)、(0.99±0.14)mmol/L]明显低于模型对照组[分别为(3.46±0.70)、(1.11±0.16)mmol/L],差异均有统计学意义(P0.05)。干预第60天,0.83μg/kg干预组血清T-AOC、GSH、SOD水平和8.33μg/kg干预组血清GSH、SOD水平均明显高于模型对照组,差异均有统计学意义(P0.05)。结论适量的酵母硒可降低雄性SD高脂血症大鼠的血脂水平,具有抗氧化能力。     

维生素E对PM_(2.5)急性染毒致大鼠心血管损伤的保护作用

目的探讨维生素E(VE)对PM_(2.5)急性染毒致大鼠心血管损伤的干预作用。方法将36只雄性SD大鼠随机分为玉米油对照组(溶剂对照组)、VE对照组、PM_(2.5)染毒组(8.0 mg/kg,以体重计,下同)、PM_(2.5)+VE低、中、高给药组,剂量分别为15.0、30.0、60.0 mg/kg。VE给药组均经VE灌胃28 d后,气管滴注PM_(2.5)悬浊液染毒,隔天1次,共3次。末次染毒24 h后,腹主动脉取血,分析测定血清中白细胞介素1-β(IL-1β)、白细胞介素6(IL-6)、肿瘤坏死因子α(TNF-α)、超敏C反应蛋白(HS-CRP);谷胱甘肽(GSH)、谷胱甘肽过氧化物酶(GSH-Px)、丙二醛(MDA)、总超氧化物歧化酶(T-SOD)、血清一氧化氮(NO)、内皮素1(ET-1)和心肌缝隙连接蛋白(Cx43)的含量。结果溶剂对照组IL-1β、IL-6、TNF-α、HS-CRP、GSH、GSH-Px、MDA、T-SOD、NO、ET-1及Cx43分别为(68.73±6.21)μg/L、(15.86±0.45)μg/L、(41.12±7.66)μg/L、(1.29±0.26)μg/L、(15.30±2.52)μmol/L、(492.29±28.28)、(10.19±0.74)μmol/L、(272.98±8.59)U/m L,(3.22±0.22)μmol/L、(0.28±0.021)μg/L、(0.42±0.04)μg/L。PM_(2.5)染毒组IL-1β[(1 155.98±100.28)μg/L]、IL-6[(24.94±2.06)μg/L]、TNF-α[(821.45±14.26)μg/L]、HSCRP[(3.10±0.28)μg/L]、MDA[(15.88±1.41)μmol/L]和ET-1[(0.38±0.03)μg/L]的释放量升高,GSH[(4.62±0.37)μmol/L]、GSH-Px[(289.28±30.65)]、NO[(0.97±0.074)μmol/L]、Cx43[(0.26±0.10)μg/L和TSOD[(239.26±4.97)U/m L]含量降低,差异有统计学意义(P0.05);与PM_(2.5)染毒组相比,VE给药组的各项指标均有一定缓解作用,差异均有统计学意义(P0.05),且存在一定的剂量反应关系。结论急性PM_(2.5)染毒可引起大鼠心血管损伤,导致炎性因子、氧化应激指标、血管内皮功能和心肌缝隙链接蛋白的变化,而VE喂饲对PM_(2.5)引起的大鼠急性肺部损伤具有一定的保护作用。     

硝酸铅诱导L-02细胞HSP70表达及氧化应激的研究

目的研究硝酸铅诱导人胚胎肝细胞株L-02细胞热应激蛋白70(HSP70)表达以及细胞氧化应激的变化,并探讨HSP70表达与抗氧化作用的关系。方法以0、10、20和40μmol/L硝酸铅染毒人胚胎肝细胞株L-02细胞,以免疫组化技术观察HSP70表达的变化,并检测L-02细胞裂解液超氧化物歧化酶(SOD)及谷胱甘肽过氧化物还原酶(GSH-Px)活力以及丙二醛(MDA)含量的变化。结果 20、40μmol/L硝酸铅组L-02细胞未出现细胞毒作用,HSP70出现阳性表达,且40μmol/L剂量组呈明显阳性;同时40μmol/L剂量组SOD活力高于对照组(P0.05)。结论该研究剂量的硝酸铅能够诱导L-02细胞HSP70表达明显增强,且细胞抗氧化作用增强。     

乙苯对大鼠肾小管上皮细胞NRK-52e氧化损伤及凋亡的影响

目的 探讨乙苯对大鼠肾小管上皮细胞NRK-52e的氧化损伤及凋亡的影响.方法 体外培养的NRK-52e细胞暴露于30、60、90、120μmol/L的乙苯24 h后,观察NRK-52e细胞形态和存活情况,用MTT法测定NRK-52e细胞的存活率,检测NRK-52e细胞内丙二醛(MDA)、谷胱甘肽(GSH)的含量及谷胱甘肽过氧化物酶(GSH-Px)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)的酶活力变化,并应用PI荧光活性染色检测乙苯致NRK-52e细胞的凋亡率.结果 30 μmol/L染毒剂量组与对照组相比,其形态学改变无明显差异,60 μmol/L及90 μmol/L染毒剂量组细胞轮廓逐渐清晰,细胞折光度增强,细胞逐渐变小变圆,皱缩成球形,部分细胞破裂;120μmol/L染毒剂量组细胞大量死亡,悬浮细胞明显增多.与对照组相比,60μmol/L、90 μmol/L及120μmol/L剂量组细胞存活率及SOD活力、GSH含量、CAT活力均显著低于对照组,差异有统计学意义(P＜0.05);90 μmol/L及120 μmol/L剂量组细胞内MDA含量及GSH-Px活力均显著低于对照组,差异有统计学意义(P＜0.05).结论 乙苯可能通过降低NRK-52e细胞内CAT、GSH-Px和SOD的酶活力及GSH含量引起细胞的氧化损伤.     

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.