体外培养条件下人骨髓间充质干细胞碱性成纤维细胞生长因子基因的转染与鉴定

背景:骨髓间充质千细胞的定向分化需要合适生长因子的调控,利用细胞因子基因转染促进其生长,定向分化和加速骨缺损修复是近年来研究热点.目的:探讨在体外培养条件下转染碱性成纤维细胞生长因子基因对人骨髓间充质干细胞生物学特性的影响.方法:将含人pcDNA3.1-bFGF真核表达载体DH-5α菌扩增,用EndoFree质粒抽提纯化试剂盒抽提质粒,并对所提取的pcDNA3.1-bFGF重组表达质粒进行酶切鉴定和测序.利用脂质体将pcDNA3.1-bFGF质粒转染到生长良好的P3代骨髓间充质干细胞,G418筛选获得抗性克隆.采用荧光定量PCR、免疫组化、免疫荧光、Westem-blot检测转染后骨髓间充质干细胞碱性成纤维细胞生长因子基因及其产物的表达,流式细胞仪检测细胞增殖周期.结果与结论:脂质体介导pcDNA3.1-bFGF重组表达质粒转染骨髓间充质干细胞后,转染细胞确实表达碱性成纤维细胞生长因子,且表达部位丰要位干胞浆.转染细胞增殖活力加强,处于增殖周期的细胞比例更高(P<0.05).提示采用脂质体转染法能将pcDNA3.1-bFGF成功导入体外培养的骨髓间充质干细胞,碱性成纤维细胞生长因子基因转染后可改善骨髓间充质干细胞的生存状态,促进其增殖.     

电穿孔介导外源性基因转染大鼠骨骼肌卫星细胞的可行性

目的:电穿孔的原理是应用短暂高压电脉冲使细胞膜形成纳米级的微孔,外源DNA通过这些微孔或者伴随微孔关闭时膜成分的再分布而直接进入细胞内.实验拟验证电穿孔法介导外源性基因转染大鼠骨骼肌卫星细胞的可行性和转染效率,以获得基因治疗自体移植的载体.方法:实验于2006-10/2007-09在暨南大学医学院中心实验室完成.①材料:清洁级1～3 d龄SD大鼠3只,购于广东省医学实验动物中心,实验过程中对动物的处置符合动物伦理学标准.基因转染过程应用的pEGFP-N1质粒由本课题组保存.②实验方法:大鼠颈椎脱臼处死,在无菌条件下分离四肢肌组织,剪碎成1 mm×1 mm×1 mm组织块,采用改良酶消化法分离骨骼肌卫星细胞,再以差速贴壁和非连续梯度离心法分两步进行纯化,细胞均匀增殖至培养面80%或局部增殖过度密集时胰酶消化传代.取第3代处于对数生长期的骨骼肌卫星细胞,消化离心后调整细胞数为2.0×107L-1,取400 μL注入4 mm电击杯中,再加入pEGFP-N1质粒15 μg混匀,将电击杯放入电转槽静置5 mim.电击条件为电容1050 μF,电压180 V,脉冲时间20 ms,脉冲数2次,脉冲间隔时间1 min,电击缓冲液为不含钙镁的磷酸盐缓冲液.放电后电击杯冰浴,并用不含血清的DMEM清洗,将清洗液转入培养瓶中,4h后换用体积分数为0.1胎牛血清的完全培养基,于37℃、体积分数为0.05的CO2无菌细胞培养箱中培养.同时设不加质粒的空白对照.③实验评估:倒置显微镜下观察细胞生长状况.免疫细胞化学检测肌动蛋白的表达.随机计数多个低倍视野,计算电穿孔pEGFP-N1质粒转染卫星细胞的效率.绘制细胞生长曲线,并用流式细胞仪测量细胞周期.结果:①骨骼肌卫星细胞的形态:原代培养48～72 h细胞完全贴壁,呈梭形或纺垂形,长轴平行排列,胞核圆形,核仁明显.5 d时细胞町伸出一个或数个突起.随培养时间的延长,卫星细胞连接成网状.当延迟分瓶或使用分化培养基,相邻的细胞会融合成肌管,继而形成串联,且能看见肌管的跳动.传代后细胞形态旱更加一致的梭形,6 h即完全贴壁,细胞增殖速度明显加快,生长更为旺盛.传至8代卫星细胞出现老化现象.②免疫细胞化学检测:骨骼肌肌动蛋白呈阳性表达.③转染效率:pEGFP-N1质粒电转染8 h后即可看见散存发绿色荧光的卫星细胞,48～72 h达高峰,阳性表达率约35%.④细胞生长曲线及细胞周期检测:电转染细胞接种后第3天进入对数生长期,第7天由于接触抑制导致增殖速度减慢,81.5%处于G0/G1期,19.3%处于S G2 M期.未转染细胞生长曲线、细胞周期均与其相似.结论:电穿孔法介导外源性基因表达于大鼠骨骼肌卫星细胞具有较高的转染效率,操作简便,重复性好,且对卫星细胞生物学行为无明显影响.     

碱性成纤维细胞生长因子基因转染对人牙周韧带细胞的作用

背景:主要来源于因正畸或阻生拔除的健康牙培养而成的人牙周韧带细胞已成为牙周组织工程理想的种子细胞来源之一。目的:了解采用重组腺相关病毒作为载体介导碱性成纤维细胞生长因子基因转染对体外培养的人牙周韧带细胞增殖及细胞周期的影响。方法:体外培养人牙周韧带细胞,经重组腺相关病毒作为载体介导碱性成纤维细胞生长因子基因转染,分为3组:对照组、空载病毒组、碱性成纤维细胞生长因子转染组。用RT-PCR,Western blot检测人牙周韧带细胞在转染前后碱性成纤维细胞生长因子基因和蛋白的表达。应用细胞生长曲线、四甲基偶氮唑蓝比色法观察细胞生长的优化作用;采用流式细胞术测定细胞周期分布的变化。结果与结论:对照组、空载病毒组未检测到碱性成纤维细胞生长因子mRNA和蛋白表达;碱性成纤维细胞生长因子转染组碱性成纤维细胞生长因子mRNA和蛋白水平均有表达,细胞的生长速度明显增快,细胞周期G0/G1期减少,S期细胞数增多。各组间比较差异有显著性意义(P<0.05)。     

碱性成纤维细胞生长因子基因转染对鼠眼外肌成肌细胞生物学行为的影响

背景:实验证明外源性的碱性成纤维细胞生长因子可以增强骨骼肌成肌细胞的生长及成活,内源性碱性成纤维细胞生长因子对肌肉修复也有明显作用。但如将其基因转染到眼外肌中也有相同的效果吗?目的:探讨碱性成纤维细胞生长因子基因转染对鼠眼外肌成肌细胞生物学行为的影响。设计:单一样本观察。单位:青岛大学医学院附属医院眼科。材料:原代大鼠眼外肌成肌细胞为前期培养得到,纯度大于90%,并成功构建人PEGFP-N3-bFGF真核表达载体(另文发表)。方法:实验于2005-09/2006-12在青岛大学医学院附属医院中心实验室完成。①实验干预及分组:实验分为试验组:用重组PEGFP-N3-bFGF转染的细胞;对照组1:空载PEGFP-N3转染的细胞;对照组2:培养皿中只加入F-10培养基(体积分数为0.1的胎牛血清)培养的细胞。采用脂质体转染技术,将重组PEGFP-N3-bFGF质粒转染体外培养的大鼠眼外肌成肌细胞中。③实验评估:用免疫组织化学法观察碱性成纤维细胞生长因子表达;用荧光显微镜检测转染效率;在培养的第1,3,5,7,9,11,13,15,21,28天采用ABC-ELISA法检测各组成肌细胞碱性成纤维细胞生长因子蛋白的分泌;采用四甲基偶氮唑盐法检测各组眼外肌成肌细胞增殖情况;根据已知一定浓度标准品的A值计算各组细胞肌酸激酶活性。主要观察指标:①观察碱性成纤维细胞生长因子基因转染体外培养的大鼠眼外肌成肌细胞的效率;转染后的表达情况。②转染后碱性成纤维细胞生长因子蛋白的分泌情况;对大鼠眼外肌肌原细胞生长和分化的影响。结果:①碱性成纤维细胞生长因子基因转染体外培养的大鼠眼外肌成肌细胞的转染率达(42.8±1.2)%。②免疫组织化学检测试验组呈现阳性反应。③转染细胞能够分泌碱性成纤维细胞生长因子蛋白,第5天最高达662.935ng/L。④转染细胞增殖活性明显提高,其A值均比同一时相点的对照组明显增高(P<0.05)。⑤转染后细胞从第5天始至终,肌酸激酶值高于对照组(P<0.01)。结论:碱性成纤维细胞生长因子基因转入大鼠眼外肌的成肌细胞中,能够使大鼠眼外肌的成肌细胞分泌碱性成纤维细胞生长因子,具有促进细胞增殖,提高其成活率,促进其分化能力。     

人骨形态发生蛋白2和人成纤维细胞生长因子2双基因共表达腺病毒载体转染人骨髓基质干细胞后的细胞增殖

背景:利用重组腺病毒载体转染外源性基因到组织工程骨的种子细胞是骨缺损基因治疗研究的热点。目的:用人骨形态发生蛋白2和人成纤维细胞生长因子2双基因共表达腺病毒载体转染人骨髓基质干细胞,以探讨基因转染对人骨髓基质干细胞增殖的影响。方法:将Ad-hBMP2-IRES-hFGF2转染至人骨髓基质干细胞中,荧光显微镜观察转染效果,RT-PCR方法观察人骨形态发生蛋白2cNDA和人成纤维细胞生长因子2cNDA在人骨髓基质干细胞中的转录情况,Westerblot方法检测人骨形态发生蛋白2和人成纤维细胞生长因子2蛋白表达情况,锥虫蓝测定细胞活力,流式细胞仪分析其对细胞增殖的影响。结果与结论:转染后人骨形态发生蛋白2和人成纤维细胞生长因子2基因在mRNA水平和蛋白水平均有表达,细胞活力无明显变化,流式细胞仪分析细胞周期中增殖细胞比例明显增加。说明该双基因可高效转染人骨髓基质干细胞,且促进细胞增殖。     

一种新的离体培养大鼠海马神经元基因转染技术

目的:探讨一种新的离体培养大鼠海马神经元基因转染方法。方法:选用17d的胚胎SD大鼠,取海马组织分离成细胞悬液,离心去上清并用混有2μg CAG-RE质粒的电转液重悬,置Neucleofector电转染仪中,选用O-03程序进行电转染,后用基础神经元培养液稀释并接种于培养皿中,4h后,待细胞贴壁时换新的神经元维持培养液,继续培养,选择不同时间点在荧光显微镜下观察,并计算在转染后4d时神经元的转染效率。结果:电转染24h后可以观察到有绿色荧光蛋白表达的转染神经元,荧光可以持续表达到2周,转染效率可达60%～80%,神经元生长良好,神经突起显示清楚。结论:电穿孔基因转染技术可以作为离体培养海马神经元很好的基因导入方法。     

人血管内皮细胞生长因子基因体外转染皮肤成纤维细胞后的表达效应

目的：观察外源性人血管内皮细胞生长因子基因导人正常真皮成纤维细胞后，能否表达及分泌血管内皮细胞生长因子，为进一步构建转VEGF165基因组织工程皮肤在创伤修复中的应用提供新移植物。 方法：实验于2001—06／2005—06在长春吉林大学完成。①真核表达载体pcDNA3．0-hVEGF165的扩增、纯化和鉴定过程为大肠杆菌DH5a感受态细胞的制备→pcDNA3．0-hVEGF165质粒DNA细菌转化→pcDNA3．0-hVEGF165质粒大量制备（碱裂解法）-质粒纯化-质粒含量纯度测定。提取的质粒载体用EeoRⅠ和xbaⅠ双酶切，琼脂糖凝胶电泳鉴定。②选取清洁级新生日本大耳白兔2只，无菌条件下取新生兔皮肤，尽量去除皮下组织，切成宽0．3cm小条块，Ⅰ型胶原酶消化，进行真皮成纤维细胞的分离与培养。脂质体介导真核表达质粒pcDNA3．0-hVEGF165转染体外培养的兔皮肤成纤维细胞，经G418筛选，获得阳性转染细胞克隆，并进行传代扩增。③酶联免疫吸附法检测转染后不同时间段的血管内皮细胞生长因子蛋白表达水平；原位杂交显示转基因细胞内VEGF165 mRNA的表达情况；流式细胞仪检测细胞周期和凋亡情况；透射电子显微镜观察转染后真皮成纤维细胞的超微结构。 结果：①质粒酶切鉴定结果：提取的质粒经双酶切、琼脂糖凝胶电泳鉴定后可得到5．4kb和0．57kb两个片段，与原质粒图谱符合，表明所提取的质粒为重组质粒pcDNA3．0-VEGF165。②pcDNA3-hVEGF165基因转染真皮成纤维细胞情况：共进行15次转染试验，35孔（皿）均有G418抗性集落形成，表明pcDNA3．0-hVEGF165经脂质体介导可有效转染正常皮肤成纤维细胞。③血管内皮细胞生长因子蛋白的表达：pcDNA3．0-hVEGF165转染成纤维细胞后，24h即有较高水平的血管内皮细胞生长因子蛋、白表达，高达（3280&;#177;2054）ng／L，并于48，72h呈下降趋势。④血管内皮细胞生长因子cDNA原位杂交检测结果：转染后成纤维细胞可见散在的阳性细胞表达hVEGF mRNA。G418应用2-4周后，可成功筛选出转基因成纤维细胞克隆，筛选后可见大量阳性的转染细胞表达hVEG FmRNA。⑤成纤维细胞的细胞周期分布及凋亡检测：转染后成纤维细胞S期细胞比例增加，G1和G2期细胞减少，表明细胞DNA的合成以及细胞的增殖活动加强。但细胞凋亡率逐渐升高。转染前为1．26％，转染后2d为2．64％，至12代时高达17135％。⑥转染后成纤维细胞超微结构观察：细胞表面有较多微绒毛，核呈不规则形，胞质内可见较多的粗面内质网、线粒体，沿膜可见一些膜包被颗粒。 结论：真核表达质粒pcDNA3．0-hVEGF165成功导人家兔皮肤成纤维细胞，在短时期内可高水平地表达分泌血管内皮细胞生长因子，在治疗缺血性疾病和促进创伤修复及以其作为种子细胞构建转基因组织工程皮肤治疗皮肤缺损等方面显示出较好的应用前景。     

重组碱性成纤维细胞生长因子基因转染对于骨髓源性成骨细胞的生物学特性及对血管生成的影响

背景:碱性成纤维细胞生长因子对来源于中胚层和神经外胚层的细胞具有明显的促进增殖作用,对骨髓间充质干细胞具有间接的成骨作用.目的:观察碱性成纤维细胞生长因子基因转染对骨髓源性成骨细胞生物学特性和血管生成的影响,与骨髓间充质干细胞作对比.设计、时间及地点:对比分析基因转染效果实验,于2007-11-27/2008-12-01在南方医科大学珠江医院中心实验室和动物实验中心完成.材料:2月龄新西兰大白兔用于骨髓间充质干细胞的分离培养及成骨细胞诱导.5周龄Wistar大鼠用于移植实验.牛pcDNA3-bFGF真核表达质粒由中山大学中山医学院免疫教研室徐霖博士惠赠.方法:分离兔骨髓间充质干细胞和骨髓源性成骨细胞,采用脂质体介导将牛pcDNA3-bFGF真核表达质粒分别转染体外培养的兔骨髓间充质干细胞和诱导的骨髓源性成骨细胞,G418筛选.稳定转染碱性成纤维细胞生长因子的骨髓源性成骨细胞与磷酸钙胶原材料复合培养,植于Wistar大鼠后腿肌袋内,正常饲养2,4周后取出植入的复合材料,观察血管新生情况.主要观察指标:碱性成纤维细胞生长因子转染前后骨髓间充质干细胞和骨髓源性成骨细胞生物学特性参数的比较以及骨髓源性成骨细胞转染碱性成纤维细胞生长因子前后新生血管数目的比较.结果:利用RT-PCR、免疫细胞化学染色分析转染细胞的碱性成纤维细胞生长因子表达情况.从形态、增殖特性和细胞周期、碱性磷酸酶、Ⅰ型胶原等方面分析稳定表达碱性成纤维细胞生长因子的骨髓间充质干细胞和骨髓源性成骨细胞生物学特性.重组牛pcDNA3-bFGF真核表达质粒成功转染目的细胞,经G418筛选稳定表达.转染的细胞有大量目的基因mRNA转录和目的蛋白表达.转染碱性成纤维细胞生长因子基因的骨髓间充质干细胞和骨髓源性成骨细胞生长均加快,细胞周期中增殖期细胞比例明显增加,细胞形态无明显变化.转染与未转染的骨髓源性成骨细胞比较,碱性磷酸酶的分泌量无明显变化(P＞0.05),转染后骨髓间充质干细胞的碱性磷酸酶分泌量小于骨髓源性成骨细胞(P＜0.01).骨髓源性成骨细胞转染与未转染碱性成纤维细胞生长因子基因组均有Ⅰ型胶原mRNA表达,但是,转染和未转染的骨髓间充质干细胞中均无Ⅰ型胶原基因mRNA转录.转染有外源性碱性成纤维细胞生长因子基因的复合材料部分被增生纤维结缔组织包绕,内有新生血管生成,随着时间的延长而增多.结论:稳定表达碱性成纤维细胞生长因子的骨髓间充质干细胞和骨髓源性成骨细胞增殖较快,但作为组织工程骨的种子细胞,骨髓源性成骨细胞较骨髓间充质干细胞更理想.外源碱性成纤维细胞生长因子基因转染后稳定表达,对新生血管的形成具有促进作用,可以作为组织工程化人工骨种子细胞转染的目的基因.     

碱性成纤维细胞生长因子基因转染大鼠骨髓间充质干细胞后目的基因的表达

目的：观察碱性成纤维细胞生长因子基因转染大鼠骨髓间充质千细胞后bFGF目的基因的表达情况，并进行影响骨髓间充质干细胞的生物学特性分析。方法：实验于2005—03／2006—02在中山大学第二附属医院医学研究中心完成。①选择近交系4周龄雄性SD大鼠10只，贴壁法分离培养骨髓间充质干细胞，构建含bFGF基因的腺病毒表达载体，利用腺病毒介导转染SD大鼠骨髓间充质干细胞。②传2代后，将细胞接种12孔培养板，培养至90％融合时弃上清，调整转染病毒滴度范围为50～400。荧光显微镜下通过观察绿色荧光强度检测转染效果，以流式细胞仪检测细胞转染效率。③传2代后，胰酶消化，置于6孔板内，每孔细胞数量5&;#215;10^5，2d后细胞贴壁生长于盖玻片上，分别转染Ad．bFGF、Ad．GFP，同时设立空白对照。转染病毒滴度选择200。应用免疫组化和Westem—Blot法鉴定碱性成纤维细胞生长因子的表达，ELISA法检测培养上清液中碱性成纤维细胞生长因子的浓度。观察转染后骨髓间充质干细胞形态和生长情况的变化。结果：①pcDNA3／bFGF的鉴定结果：成功构建碱性成纤维细胞生长因子腺病毒表达载体。②Ad．GFP转染骨髓间充质干细胞的效率测定：转染48h后，绿色荧光蛋白的表达明显增强。当转染病毒滴度≤200时，腺病毒的转染效率与病毒剂量呈明显的正相关（P〈0．05），当〉200时转染效率趋于稳定，均在96％以上。③Ad．bFGF转染骨髓间充质干细胞的表达情况：bFGF蛋白表达免疫组化检测可见转染Ad．bFGF骨髓间充质干细胞的胞浆内充满棕褐色颗粒，阳性表达率为86％，而转染Ad．GFP及空白对照的骨髓间充质干细胞均为阴性。Western—Blot示转染Ad．bFGF的细胞裂解产物中碱性成纤维细胞生长因子含量明显高于转染Ad．GFP及空白对照。ELISA检测结果表明转染Ad．bFGF的细胞培养上清液中碱性成纤维细胞生长因子浓度第15天达高峰1467ng／L，此后逐渐下降，但至转染第28天时仍显著高于空白对照（441ng／L，128ng／L，t=4．31，P〈0．01）。④转染Ad．bFGF对骨髓间充质干细胞增殖的影响：骨髓间充质干细胞的增殖分化没有明显变化。结论：采用腺病毒介导的基因转染技术可以将碱性成纤维细胞生长因子转染至骨髓间充质干细胞中，并有外源性基因和蛋白的表达。提示骨髓间充质干细胞是碱性成纤维细胞生长因子基因治疗的理想载体。     

骨骼肌卫星细胞的体外培养与生物学特性

目的：建立理想的骨骼肌卫星细胞体外培养方法，探讨其生物学特性、以达到应用于组织工程和基因治疗的目的：方法：采用Ⅰ型胶原酶和胰蛋白酶二步消化法获取大鼠骨骼肌卫星细胞，进行体外原代和传代培养。观察细胞的形态，通过生长曲线、细胞融合率研究骨骼肌卫星细胞的增殖与分化能力，利用免疫细胞化学染色对所获得的细胞进行鉴定。结果：二步消化法适用于骨骼肌卫星细胞的获取。在生长培养基作用下，细胞增殖旺盛；在分化培养基条件下，细胞分化良好，可融合成肌管。α-sarcometric肌动蛋白和肌球蛋白细胞免疫化学染色，骨骼肌卫星细胞弱阳性，肌管强阳性。结论：体外培养的骨骼肌卫星细胞具有良好的增殖与分化能力，适用于组织工程和基因治疗。     

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.     

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.     

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.