改构型和野生型酸性成纤维细胞生长因子对肠缺血-再灌注损伤的保护作用及剂量-效应关系研究

目的评价改构型和野生型酸性成纤维细胞生长因子(aFGF)对肠缺血-再灌注损伤后肠道保护作用的机制及剂量-效应关系。方法以夹闭大鼠肠系膜上动脉(SMA)制备肠缺血-再灌注损伤模型，并将动物随机分为假手术组、生理盐水对照组、不同剂量(2、4和8μg)改构型aFGF治疗组和4μg野生型aFGF治疗组。除假手术组外，其余各组动物均于缺血45min后再灌注2、6、12和24h活杀，取血及小肠组织标本，检测血浆中D-乳酸含量及组织中增殖细胞核抗原(PCNA)的表达特性，并检测肝、肾功能指标，观察不同剂量aFGF对肠缺血-再灌注损伤的影响。结果血浆D-乳酸变化及病理组织学观察显示，再灌注后12h肠屏障功能及肝、肾组织损伤最严重，而改构型aFGF 4μg治疗组在伤后24h损伤较生理盐水对照组和野生型aFGF治疗组有所减轻。PCNA的表达趋势与D-乳酸类似。结论改构型aFGF对肠缺血-再灌注损伤具有一定保护与促修复作用，其抗损伤修复作用呈剂量依赖性。     

参附注射液对再灌注期间肠黏膜上皮细胞凋亡的抑制

背景肠上皮细胞异常凋亡是缺血再灌注期间肠黏膜损伤的主要原因,参附注射液对小肠黏膜损伤有良好的防治作用.目的建立大鼠肠缺血再灌注模型,观察缺血再灌注时给予参附注射液对肠上皮细胞凋亡数目、凋亡相关基因半胱氨酸天冬氨酸蛋白酶-3、Bcl-2的表达及肿瘤坏死因子水平的影响.设计随机对照实验.单位武汉大学人民医院麻醉科.材料实验于2002-12/2003-06在武汉大学人民医院麻醉科实验室完成.选取健康清洁级SD大鼠24只,随机分为空白对照组、肠缺血再灌注组、参附注射液组,8只/组.方法各组大鼠给予氨基甲酸乙酯1 mg/kg腹腔注射麻醉,肠缺血再灌注组和参附注射液组用血管钳夹闭肠系膜上动脉1 h然后再灌注2 h,空白对照组不用血管钳夹闭肠系膜上动脉.参附注射液组于阻断前30 min静注参附注射液0.02 mL/g,空白对照组和肠缺血再灌注组静脉输注等量生理盐水.制备切片进行半胱氨酸天冬氨酸蛋白酶-3、Bcl-2蛋白的表达及细胞凋亡检测.主要观察指标①各组大鼠细胞凋亡指数的比较.②各组大鼠肠上皮细胞半胱氨酸天冬氨酸蛋白酶-3及Bcl-2基因的表达.③各组肠粘膜匀浆中肿瘤坏死因子含量的比较.结果实验选用24只大鼠,全部进入结果分析.①各组大鼠细胞凋亡指数的比较参附注射液组的凋亡指数明显低于肠缺血再灌注组,但比空白对照组高[(7.75±1.89)%,(28.25±8.50)%,(4.25±2.63)%,P均＜0.01].②各组大鼠肠上皮细胞半胱氨酸天冬氨酸蛋白酶-3及Bcl-2基因的表达参附注射液组组半胱氨酸天冬氨酸蛋白酶-3的表达低于肠缺血再灌注组,但高于空白对照组[(0.211 6±0.087 5),(0.354 7±0.077 8),(0.194 1±0.057 4),P＜0.01,P＞0.05];Bcl-2的表达在肠缺血再灌注组比空白对照组显著增高(P＜0.05),参附注射液组的表达比肠缺血再灌注组明显降低(P＜0.01).③各组肠黏膜匀浆中肿瘤坏死因子含量的比较砀缺血再灌注组肿瘤坏死因子的表达显著高于空白对照组和参附注射液组[(189.7±56.3),(38.6±10.4),(47.5±18.7)mg/L,P均＜0.01],参附注射液组和空白对照组基本相似(P＞0.05).结论参附注射液通过抑制肿瘤坏死因子的含量、降低半胱氨酸天冬氨酸蛋白酶-3的表达、上调Bcl-2基因而抑制缺血再灌注期间肠黏膜上皮细胞的凋亡,从而减轻肠黏膜缺血再灌注损伤.     

促红细胞生成素对大鼠脑组织缺血再灌注海马CA1区神经元的作用

目的:观察促红细胞生成素对缺血再灌注大鼠脑组织海马CA1区神经元数量以及凋亡细胞数量变化、热休克蛋白70表达的影响。方法:实验于2003-03/2004-12在解放军第三军医大学新桥医院中心实验室完成。选择健康清洁级Wistar大鼠66只,随机分为正常对照组6只、缺血再灌注生理盐水组30只(生理盐水对照组)、缺血再灌注促红细胞生成素组30只(促红细胞生成素治疗组)。线栓法制备大鼠大脑中动脉阻断局灶性脑缺血模型,缺血2h后再灌注,促红细胞生成素治疗组经腹腔按200U/kg注入生理盐水稀释的重组人红细胞生成素(200U/mL),生理盐水对照组经腹腔注入等量的生理盐水。再灌注后观察时相点为2,6,12,24,48h,应用苏木精-伊红染色观察脑海马CA1区细胞数量情况,应用末端脱氧核苷酸转移酶缺口标记法检测海马CA1区神经元凋亡情况,应用免疫组织化学法测定热休克蛋白70表达情况。结果:66只大鼠全部进入结果分析。①脑海马CA1区细胞的计数:生理盐水对照组再灌注后12,24,48h比正常对照组细胞数明显减少犤(268.6±44.5)个/视野,(240.8±22.5)个/视野,(201.8±30.7)个/视野,(337.3±45.3)个/视野,t=2.845～5.587,P<0.01犦,促红细胞生成素治疗组再灌注后12,24,48h比生理盐水对照组细胞数明显增加犤(286.7±33.8)个/视野,(271.9±30.4)个     

α-黑素细胞刺激素对抗大鼠肠缺血再灌注损伤的作用及机制

目的探讨α-黑素细胞刺激素(α-MSH)对抗大鼠肠缺血再灌注损伤的作用及机制。方法60只大鼠随机数字表法分3组假手术组、缺血再灌注组和治疗组,每组20只。采用大鼠小肠缺血60min再灌注模型,治疗组静脉注射α-MSH,用放免法检测血中肿瘤坏死因子-α(TNF-α)、白细胞介素6含量,用髓过氧化物酶(MPO)定量测定法评价缺血后肠组织中中性粒细胞浸润程度,免疫组化法检测肠黏膜Fas蛋白表达情况,并电镜观察超微结构的改变。结果α-MSH能明显改善电镜下细胞超微结构的损害;与缺血再灌注组比较,治疗组再灌注后肠组织Fas表达下调,其光密度值由1.4509±0.0192下降为1.3241±0.0140,MPO,TNF-α,白细胞介素6含量于再灌注后6h,分别由(8.50±0.150)nkat/g下降为(5.17±0.317)nkat/g,(1.86±0.53)μg/g下降为(1.41±0.39)μg/g,(301.06±67.23)ng/g下降为(201.56±26.42)ng/g,两组比较差异有显著性意义(P<0.05)。结论α-MSH可能通过减轻肠缺血后炎症反应以及阻止肠组织细胞凋亡的发生等机制对肠缺血再灌注损伤具有保护作用。     

碱性成纤维细胞生长因子及WTp53在大鼠视网膜缺血再灌注损伤中的作用

目的:探讨碱性成纤维细胞生长因子(basicfibroblastgrowthfactor,bFGF)在大鼠视网膜缺血再灌注损伤中的作用及其机制。方法:随机将28只大鼠分为正常组和手术组,其中手术组大鼠左眼为缺血再灌注组,右眼为治疗组(玻璃体腔内注射bFGF),观察再灌注后不同时间段1,6,12,24,48,72h视网膜组织中细胞凋亡情况及WTp53的表达变化。前房加压法制作大鼠视网膜缺血再灌注损伤模型。应用末端脱氧核酸转移酶介导的脱氧三磷酸尿苷缺口末端标记(TUNEL)法检测视网膜组织中凋亡细胞数,免疫组织化学SABC法检测视网膜组织中WTp53蛋白的表达。结果:视网膜神经细胞的凋亡出现于再灌注后6h,并逐渐递增,24h达到高峰,48h开始下降,72h组不明显。WTp53蛋白表达改变与凋亡的神经细胞改变基本一致。治疗组各观察指标表达变化规律与缺血再灌注组基本一致,但凋亡细胞数目在6～48h犤6,12,24,48h分别为(358.3±43.4),(859.5±12.0),(1006.5±49.4),(695.7±72.2)个/mm2犦明显低于缺血再灌注组犤(444.8±89.7),(1053.0±96.1),(1254.0±164.8),(891.0±87.2)个/mm2犦(t=2.9131～4.299,P均<0.05);WTp53表达在6～48h缺血再灌注组显著下降(t=3.342～4.781,P<0.05;t=52.586,P<0.01)。结论:WTp53参与视网膜缺血-灌注损伤,促进神经节细胞的凋亡;bFG     

缺血缺氧再灌注不同损伤程度人脐静脉内皮细胞变化与清开灵的干预效应(英文)

背景:“毒损脑络”是急性脑血管病的主要病机,以脑微血管损伤为主要表现。目的:建立不同缺氧缺血再灌注时间的细胞模型及施加药物干预,观察清开灵注射液对不同损伤程度人脐静脉内皮细胞ECV304的保护作用。设计:以培养的细胞为观察对象的随机对照实验。单位:华中科技大学同济医学院附属协和医院中西医结合科。材料:实验于2002-02/04在北京中医药大学附属东直门医院中心实验室完成。实验用人脐静脉内皮细胞ECV304随机分为7组,即正常组、缺氧6h再灌注12h对照组、缺氧24h再灌注12h对照组、缺氧24h再灌注12h低浓度清开灵组、缺氧24h再灌注12h中浓度清开灵组、缺氧24h再灌注12h高浓度清开灵组、缺氧6h再灌注12h中浓度清开灵组。清开灵注射液主要成分为牛胆酸、猪去氧胆酸、黄芩苷、栀子总苷等。方法:缺血再灌注模型的制作:①从培养箱中取出培养的细胞,缺氧6h再灌注12h对照组、缺氧24h再灌注12h对照组分别吸除原培养液,换入无糖Earle’s液,细胞放入缺氧槽中37℃缺血缺氧培养。缺氧6h再灌注12h对照组培养6h,缺氧24h再灌注12h对照组培养24h后,分别吸去无糖Earle’s液,换入无血清1640液后置于37℃CO2培养箱中再灌注培养12h。②缺氧24h再灌注12h低浓度清开灵组、缺氧24h再灌注12h中浓度清开灵组、缺氧24h再灌注12h高浓度清开灵组分别在缺氧24h再灌注12h对照组造模的基础上,向各自培养液中加入质量浓度为5,10,20mg/L的清开灵对细胞进行培养。③缺氧6h再灌注12h中浓度清开灵组在缺氧6h再灌注12h对照组造模的基础上,向培养液中加入质量浓度为10mg/L的清开灵。④细胞存活率以四唑盐比色试验测定,乳酸脱氢酶漏出率用乳酸脱氢酶试剂盒测定,细胞凋亡率行碘化吡啶染色后用流式细胞仪检测,Cellquest软件进行分析。主要观察指标:①细胞形态学观察结果。②各组细胞存活率、乳酸脱氢酶漏出率及细胞凋亡率。结果:①细胞形态学观察:正常组细胞密集,贴壁良好,伸展充分,细胞表面光滑,有较多的分裂期细胞,细胞长满底面,呈典型的“铺路石征”;缺氧6h再灌注12h对照组及缺氧24h再灌注12h低浓度清开灵组细胞形态改变不明显;缺氧24h再灌注12h对照组细胞较稀疏,脱壁较多,可见大量肿胀变圆的损伤细胞及破碎细胞的碎片,贴壁细胞皱缩明显,可见伪足,分裂期细胞少;缺氧24h再灌注12h中浓度清开灵组细胞贴壁良好,表面光滑,未发生皱缩,可见分裂期细胞。②各组ECV304细胞存活率:与缺氧24h再灌注12h对照组比较,缺氧24h再灌注12h低浓度清开灵组、缺氧24h再灌注12h中浓度清开灵组均显著升高犤(42.5±2.8),(72.9±8.0),(80.3±12.7)%,P均<0.01犦,而缺氧24h再灌注12h高浓度清开灵组则显著下降至(10.1±0.4)%,P<0.01。正常组为100%。③各组ECV304细胞乳酸脱氢酶漏出率:与缺氧24h再灌注12h对照组比较,缺氧24h再灌注12h低浓度清开灵组、缺氧24h再灌注12h中浓度清开灵组均显著升高犤(6.6±1.4),(2.4±1.4),(2.4±0.5)%,P均<0.01犦,而缺氧24h再灌注12h高浓度清开灵组则显著升高至(16.1±2.2)%,P<0.01。正常组为(2.2±1.0)%。④各组ECV304细胞凋亡率:与缺氧6h再灌注12h对照组比较,缺氧6h再灌注12h中浓度清开灵组明显升高犤(2.2±0.5),(1.5±0.4)%,P<0.05犦;与正常组比较,缺氧24h再灌注12h对照组、缺氧24h再灌注12h中浓度清开灵组均显著升高犤(0.9±0.2),(5.5±2.5),(9.9±4.3)%,P均<0.01犦;并且缺氧24h再灌注12h中浓度清开灵组比与缺氧24h再灌注12h对照组升高更明显(P<0.01)。结论:①清开灵注射液对不同程度缺血再灌注损伤的ECV304细胞均有保护作用,但随着损伤程度的不同而表现为两种相反的保护形式。②对于缺血6h再灌注12h此类受损伤较轻的ECV304细胞,主要表现为降低细胞的凋亡率;而对于缺血24h再灌注12h此类缺血再灌注损伤较重的ECV304细胞,则增加细胞的凋亡率,使坏死的细胞减少。③与坏死细胞相比,凋亡细胞不发生溶酶体、线粒体及胞膜的破裂,没有内涵物的外泄,故不引起周围细胞的次级损伤,从而提高了细胞存活率,起到保护大多数细胞的作用。     

全脑缺血再灌注损伤大鼠海马神经元凋亡:调节蛋白Bcl-2和Bax的表达(英文)

背景:脑缺血再灌注对中枢神经系统的影响,除了急性期的细胞坏死,还有迟发性的神经元凋亡。目的:观察大鼠全脑缺血不同再灌注阶段海马神经元凋亡率、坏死率及凋亡调节蛋白Bcl-2和Bax的表达情况,并探讨其对全脑缺血再灌注损伤的调节作用。设计:随机对照实验。单位:首都医科大学附属北京天坛医院的神经外科和麻醉科。材料:实验于2003-01/2004-01在首都医科大学附属北京神经外科研究所完成。选择清洁级成年雄性健康Wistar大鼠33只,随机分5组,缺血再灌注24h组7只、缺血再灌注48h组7只、缺血再灌注72h组7只、缺血再灌注7d组7只和假手术对照组5只。干预:制备大鼠全脑缺血再灌注模型。分别于再灌注24,48,72h和7d取脑海马组织,用流式细胞仪检测细胞凋亡率,坏死率,Bcl-2和Bax蛋白在大鼠脑海马神经元中的表达情况。主要观察指标:①流式细胞仪检测各组大鼠脑海马组织细胞凋亡率和坏死率。②Bcl-2和Bax蛋白表达百分率。结果:33只大鼠全部进入结果分析。①缺血再灌注7d组海马神经元的凋亡率最高犤(24.59±0.97)%犦,坏死率峰值出现在缺血再灌注24h组犤(16.67±1.04)%犦,明显高于假手术对照组犤(1.28±0.50)%,(0.90±0.38)%犦(P<0.01)。②假手术对照组Bcl-2表达极低犤(1.07±0.27)%犦,但Bax有高表达犤(46.09±5.37)%犦。③Bcl-2蛋白峰值出现在缺血再灌注后48h犤(14.41±0.67)%犦,而Bax蛋白峰值出现在缺血再灌注之后72h犤(77.38±1.52)%犦。结论:全脑缺血再灌注损伤后海马神经元凋亡率逐渐增高,凋亡调控基因Bcl-2和Bax表达异常增高,提示Bcl-2和Bax蛋白参与了全脑缺血再灌注损伤的凋亡调节。     

大鼠脑组织缺血再灌注后促红细胞生成素对神经元的保护

目的:观察促红细胞生成素对缺血再灌注大鼠脑组织海马CA1区神经元数量、凋亡细胞数量变化、脑组织匀浆一氧化氮含量、丙二醛含量及超氧化物歧化酶活性改变的影响。方法:实验于2003-03/2004-12在解放军第三军医大学附属新桥医院中心实验室完成。选择健康Wistar大鼠66只,随机分为正常对照组6只,缺血再灌注生理盐水组30只(生理盐水对照组),缺血再灌注促红细胞生成素组30只(促红细胞生成素治疗组)。除正常对照组线栓法制备大鼠大脑中动脉阻断局灶性脑缺血模型,缺血2h后再灌注。促红细胞生成素组于再灌注开始时经腹腔按2000U/kg注入生理盐水稀释的重组人红细胞生成素(200U/mL),生理盐水对照组经腹腔注入等量的生理盐水。再灌注后观察时相点为2,6,12,24,48h,每个时间点6只。应用苏木精-伊红染色观察脑海马CA1区细胞数量情况,应用末端脱氧核苷酸转移酶缺口标记法检测海马CA1区神经元凋亡情况,应用硝酸还原酶法测定脑组织一氧化氮含量,羟胺法测定脑组织超氧化物歧化酶活性,硫代巴比妥酸法测定脑组织中丙二醛含量。结果:66只大鼠全部进入结果分析。①脑海马CA1区细胞计数:促红细胞生成素治疗组再灌注后12,24,48h比生理盐水对照组细胞数明显增加犤(286.7±33.8),(268.6±44.5)个/视野;(271.9±30.4),(240.8±22.5)     

胰岛素对大鼠脑缺血再灌注时神经元凋亡及其相应基因的调控

目的观察胰岛素(insulin,RI)对缺血再灌注损伤后细胞凋亡及其相应基因的调控作用,评估RI对脑缺血再灌注损伤的保护作用。方法将健康wistar大鼠56只,随机分为对照组、缺血再灌注盐水组(NS)、缺血再灌注胰岛素组(RI)。采用pulsinelli4血管阻塞模型,观察RI、NS在4,24,48h海马CA1区存活神经元数目,TUNEL阳性细胞数目,Bcl-2蛋白的表达,以观察比较缺血再灌注阶段细胞凋亡的变化。结果再灌注NS组CA1区神经元数目(36±6)个/mm2较再灌注RI组(88±9)个/mm2少(t=3.34,P<0.01)。再灌注后CA1区细胞凋亡数:4h时再灌注NS组(12±3)个/mm2高于再灌注RI(8±1)个/mm2和假手术组(2±1)个/mm2:组间比较,F=127.66,P<0.001。Bcl-2对海马CA1细胞凋亡评估4h时,再灌注NS组43.0±9.8,高于再灌注RI组24.0±5.4和假手术组2.7±0.8。结论全脑缺血再灌注时急用RI可减轻脑缺血再灌注神经元凋亡,对脑缺血再灌注损伤引起的神经元延迟性坏死有保护作用。     

亚低温缺血预处理对大鼠肠缺血再灌注诱导细胞凋亡的保护

背景细胞凋亡在肠缺血再灌注损伤中起关键性作用,细胞凋亡的发生与凋亡抑制基因Bcl-2和凋亡促进基因Bax蛋白表达程度密切相关.目的探讨亚低温缺血预处理对大鼠肠组织缺血再灌注后凋亡相关基因Bcl-2和Bax蛋白表达的影响.设计随机对照实验.单位湖北省咸宁学院医学院外科学教研室与生物化学教研室.材料实验于2002-04/12在咸宁学院医学院中心实验室完成.选用Wistar健康雄性大鼠32只,术前禁食24 h,自由饮水.随机分为假手术对照组、缺血再灌注组、缺血预处理组、亚低温预处理组,8只/组.方法除假手术对照组外,其余3组建立缺血再灌注模型.①假手术对照组仅暴露肠系膜上动脉而不夹闭,共2 h,结束实验后取材;缺血再灌注组夹闭肠系膜上动脉60min后松夹60 min再取材;缺血预处理组夹闭肠系膜上动脉5 min和松夹5 min作为预处理,余同缺血再灌注组;亚低温预处理组实施缺血预处理前在小肠周围充填碎冰造成小肠亚低温(33～35℃),余同缺血预处理组.②各组大鼠取中段小肠4 cm,分为两段,分别置于甲醛和戊二醛中固定,制作电镜标本.免疫组化后显微镜下用图像分析系统检测各组吸光度值,每组选10个视野进行测量,计算平均值,肠黏膜损伤按Chiu标准进行分级.0级正常黏膜绒毛;Ⅰ级上皮下间隙增大,通常在绒毛的尖端,常伴有毛细血管淤血;Ⅱ级上皮下间隙扩张伴随上皮层同固有层中度分离;Ⅲ级绒毛两侧上皮层大量的同固有层分离,部分绒毛顶端破损;Ⅳ级绒毛破损伴随固有层毛细血管暴露,可能观察到固有层的细胞成分增多;Ⅴ级固有层破坏和不完整、出血和溃疡.主要观察指标①各组肠缺血再灌注后Bcl-2与Bax蛋白吸光度值的变化.②各组肠黏膜损伤分级.③各组肠黏膜组织学变化.结果32只大鼠全部进入结果分析,中途无脱落.①各组肠缺血再灌注后Bcl-2与Bax蛋白吸光度值的变化与假手术对照组比较,缺血再灌注组均明显升高(4.03±1.02,9.56±1.32,P＜0.01;5.67±1.34,19.07±1.63,P＜0.01);与缺血再灌注组比较,缺血预处理组Bcl-2表达升高(9.56±1.32,15.03±1.44,P＜0.01),Bax表达降低(19.07±1.63,14.11±1.21,P＜0.01);与缺血预处理组比较,亚低温预处理组Bcl-2表达仍有所升高(15.03±1.44,18.17±2.03,P＜0.05),Bax表达仍降低(14.11±1.21,11.58±1.04,P＜0.05).②各组肠黏膜损伤分级情况假手术对照组肠黏膜基本正常,损伤均为0级;缺血再灌注组肠黏膜损伤Ⅱ级2只,Ⅲ级3只,Ⅳ级3只,明显高于假手术对照组(P＜0.01);缺血预处理组肠黏膜损伤Ⅰ级2只,Ⅱ级4只,Ⅲ级2只,明显低于缺血再灌注组(P＜0.01);亚低温预处理组肠黏膜损伤0级1只,Ⅰ级3只,Ⅱ级4只,低于缺血预处理组(P＜0.05).③各组肠黏膜组织学形态电镜观察结果假手术对照组肠黏膜上皮微绒毛排列整齐,各细胞器形态正常;缺血再灌注组肠黏膜上皮微绒毛稀疏、变短、脱落,线粒体明显肿胀,空泡变性,内质网排列紊乱、肿胀;缺血预处理组肠黏膜上皮微绒毛排列基本整齐,线粒体内质网轻度肿胀;而亚低温预处理组肠黏膜上皮微绒毛排列整齐,线粒体内质网肿胀不明显.结论肠缺血再灌注前进行缺血预处理可以上调Bcl-2蛋白的表达,并下调Bax蛋白的表达,从而抑制肠缺血再灌注诱导的细胞凋亡以保护缺血再灌注肠损伤.亚低温状态能增强缺血预处理的保护作用.     

Determination of creatine kinase isoenzyme MB activity in serum using immunological inhibition of creatine kinase M subunit activity. Activity kinetics and diagnostic significance in myocardial infarction.

This is a new method for the determination of creatine kinase isoenzyme MB activity in serum. The method uses direct activity measurement of creatine kinase B subunit activity after blocking of CK-M subunit activity by inhibiting antibodies. The test takes no longer than 15 min. The method yields an intra-serial C.V. of 2.0-12.9%, and a C.V. from day to day of 5.5%. The detection limit is 3.4 U/l creatine kinase MB. In the 95 cases with proven myocardial infarction several types of creatine kinase MB activity kinetics could be determined. The percentage of creatine kinase MB of peak CK-total is 6-25%, with a mean of 11.1%. The amount of creatine kinase MB with respect to total CK activity after reinfarction is higher than the amount after initial infarction.     

Dissociable correlates of two classes of retrieval processing in prefrontal cortex

Although substantial evidence suggests that the prefrontal cortex (PFC) implements processes that are critical for accurate episodic memory judgments, the specific roles of different PFC subregions remain unclear. Here, we used event-related functional magnetic resonance imaging to distinguish between prefrontal activity related to operations that (1) influence processing of retrieval cues based on current task demands, or (2) are involved in monitoring the outputs of retrieval. Fourteen participants studied auditory words spoken by a male or female speaker and completed memory tests in which the stimuli were unstudied foil words and studied words spoken by either the same speaker at study, or the alternate speaker. On "general" test trials, participants were to determine whether each word was studied, regardless of the voice of the speaker, whereas on "specific" test trials, participants were to additionally distinguish between studied words that were spoken in the same voice or a different voice at study. Thus, on specific test trials, participants were explicitly required to attend to voice information in order to evaluate each test item. Anterior (right BA 10), dorsolateral prefrontal (right BA 46), and inferior frontal (bilateral BA 47/12) regions were more active during specific than during general trials. Activation in anterior and dorsolateral PFC was enhanced during specific test trials even in response to unstudied items, suggesting that activation in these regions was related to the differential processing of retrieval cues in the two tasks. In contrast, differences between specific and general test trials in inferior frontal regions (bilateral BA 47/12) were seen only for studied items, suggesting a role for these regions in post-retrieval monitoring processes. Results from this study are consistent with the idea that different PFC subregions implement distinct, but complementary processes that collectively support accurate episodic memory judgments.     

俯卧位通气对高海拔地区肺复张治疗无效急性呼吸窘迫综合征患者氧合的影响

目的 探讨俯卧位通气对高海拔地区肺复张术(RM)治疗无效急性呼吸窘迫综合征(ARDS)患者的治疗作用.方法 从海拔2260m的地区医院筛选RM治疗无效的41例ARDS患者[平均氧合指数( PaO2/FiO2)较RM前升高＜20％视为RM无效],依不同病因分为肺内源性ARDS组(ARDSp组)和肺外源性ARDS组(ARDSexp组),每组再按信封法随机分为俯卧位组和仰卧位组,即ARDSp俯卧位组(11例)、ARDSp仰卧位组(9例)、ARDSexp俯卧位组(10例)、ARDSexp仰卧位组(11例).在通气前及通气1、2、3、4h监测动脉血氧分压( PaO2)、PaO2/FiO2、静态顺应性(Cst)、气道阻力(Raw)的变化.结果 通气lh时,ARDSexp俯卧位组PaO2/FiO2( mm Hg,l mm Hg=0.133 kPa)即较通气前显著升高(157.4±40.6比129.3±48.7,P＜0.05),并随通气时间延长呈持续增高趋势,4h达峰值(219.1 ±41.1);且ARDSexp俯卧位组通气3h内PaO2/FiO2较其他3组显著增高,另3组间则差异无统计学意义.ARDSp俯卧位组、ARDSexp俯卧位组通气4h时PaO2/FiO2均较相应仰卧位组显著增高(208.8±39.7比127.4±47.1,219.1±41.1比124.9±50.8,均P＜0.05).4组通气前后Cst无显著改变,各组间差异也无统计学意义.ARDSp俯卧位组通气4h时Raw(cmH2O·L-1·s-1)较通气前显著降低(6.8±1.7比10.7±1.8,P＜0.05),且明显低于其他3组;其他3组各时间点Raw组内及组间比较差异均无统计学意义.结论 俯卧位通气作为ARDS机械通气重要策略之一,可以改善RM无效高原ARDS患者的氧合,为抢救患者赢得宝贵的时间.     

Digital imaging among medical facilities

The Department of Veterans Affairs (VA) in the USA operates a network of 172 medical centres which all utilize a hospital information system (HIS) which has been developed and is currently maintained by the VA. During the past several years, an image management and communication module has been developed, installed and clinically utilized at the Washington DC and Maryland VA Medical Centres. This image management and communication system, referred to as the decentralized hospital computer program (DHCP) imaging system, is fully integrated with a commercial picture archiving and communication system (PACS). The system is utilized to capture, archive, and display all images generated within the hospital including radiology, nuclear medicine, pathology, endoscopy, bronchoscopy, and dermatology, intraoperative photographs, ECG data, and a limited number of paper documents. The ultimate goal of the project is to have all patient text and image data available at any clinical workstation to any authorized user anywhere within the network of medical centres. Clinical requirements for an imaging workstation include ease of use, rapid and reliable access to the complete set of patient information, and images which are of acceptable quality to meet the requirements of the user and the subspecialty. Patient confidentiality and data security must be safeguarded at all times. Integration of the images with the remainder of the patient's database was found to be critical to the success of the project. The experience at the Washington and Maryland facilities suggests that an imaging system that is successfully integrated with a hospital information system can provide substantial clinical and economic benefits both within and among medical centres. Clinical acceptance and utilization of the system has been excellent, particularly in diagnostic radiology where DHCP Imaging has been interfaced to a commercial PAC system. Based upon this initial experience, the VA has begun to deploy the system throughout its large network of medical centres.     

Myocardial elastography at both high temporal and spatial resolution for the detection of infarcts

Myocardial elastography is a novel method for noninvasively assessing regional myocardial function, with the advantages of high spatial and temporal resolution and high signal-to-noise ratio (SNR). In this paper, in-vivo experiments were performed in anesthetized normal and infarcted mice (one day after left anterior descending coronary artery [LAD] ligation) using a high-resolution (30 MHz) ultrasound system (Vevo 770, VisualSonics Inc., Toronto, ON, Canada). Radiofrequency (RF) signals of the left ventricle (LV) in longitudinal (long-axis) view and the associated electrocardiogram (ECG) were simultaneously acquired. Using a retrospective ECG gating technique, 2-D full field-of-view RF frames were acquired at an extremely high frame rate (8 kHz) that resulted in high-quality incremental displacement and strain estimation of the myocardium. The incremental results were further accumulated to obtain the cumulative displacements and strains. Two-dimensional and M-mode displacement images and strain images (elastograms), as well as displacement and strain profiles as a function of time, were compared between normal and infarcted mice. Incremental results clearly depicted cardiac events including LV contraction, LV relaxation and isovolumetric phases in both normal and infarcted mice, and also evidently indicated reduced motion and deformation in the infarcted myocardium. The elastograms indicated that the infarcted regions underwent thinning during systole rather than thickening, as in the normal case. The cumulative elastograms were found to have higher elastographic SNR (SNR(e)) than the incremental elastograms (e.g., 10.6 vs. 4.7 in a normal myocardium, and 6.0 vs. 2.4 in an infarcted myocardium). Finally, preliminary statistical results from nine normal (m = 9) and seven infarcted (n = 7) mice indicated the capability of the cumulative strain in differentiating infracted from normal myocardia. In conclusion, myocardial elastography could provide regional strain information at simultaneously high temporal (>/=0.125 ms) and spatial ( approximately 55 microm) resolution as well as high precision ( approximately 0.05 microm displacement). This technique was thus capable of accurately characterizing normal myocardial function throughout an entire cardiac cycle, at the same high resolution, and detecting and localizing myocardial infarction in vivo.     

手转胎头术失败的原因与分娩结局临床分析

目的 探讨手转胎头术失败的原因与分娩结局.方法 选择2008年1月至2010年12月于我院住院分娩的持续性枕横位、枕后位产妇198例,根据行手转胎头术后结果分为成功组126例、失败组72例.比较两组分娩结局,对比分析失败原因.结果 失败组胎儿体质量≥3500 g的发生率[76.4％(55/72)]明显高于成功组[31.7％(40/126)],差异有统计学意义(x2=30.177,P=0.001)、失败组宫缩乏力发生率[58.3％(42/72)]高于成功组[38.1％ (48/126)],差异有统计学意义(x2=7.569,P=0.006)、失败组骨盆临界或轻度狭窄发生率[38.9％ (28/72)]高于成功组[23.8％(30/126)],差异有统计学意义(x2 =5.030,P=0.002)、失败组手转胎头时机不当(宫口开大＜6 cm、胎头位于坐骨棘上及宫口开大8～10 cm、胎头位于坐骨棘下≥2 cm)发生率[61.1％(44/72)]高于成功组[38.9％(49/126)],差异有统计学意义(x2=9.084,P=0.003).失败组母儿并发症(产后出血、产褥病率、胎儿窘迫、新生儿窒息)发生率高于成功组(x2 =9.586,P=0.002、x2=9.334,P=0.002、x2=5.910,P=0.015、x2=5.240,P=0.022)、失败组剖宫产发生率[72.2％(52/72)]明显高于成功组[34.1 ％(43/126),x2=26.641,P=0.001)].结论 手转胎头术能使难产变顺产,降低剖宫产率,减少母儿并发症,但须积极预防、处理导致手转胎头术失败的原因,对矫正失败后继续矫正及试产应慎重.