骨骼肌卫星细胞移植对心肌梗死大鼠心肌纤维化的影响

背景:现已发现心肌梗死后心肌纤维化是心室重构的重要机制,而相关干细胞心肌移植对这一过程的影响报道不多.目的:观察自体骨骼肌卫星细胞移植对心肌梗死大鼠心肌纤维化的影响,并探讨其可能机制.设计、时间及地点:随机对照动物实验,于2007-07/09在解放军第三军医大学大坪医院野战外科研究所第三研究室完成.材料:Wistar 大鼠45只,雌雄各半,体质量150～200 g,其中30只用于制备心肌梗死模型.方法:45只大鼠按随机抽签法分为3组,每组15只.心肌梗死组:结扎冠状动脉左前降支造成心肌梗死,2周后沿梗死区与正常心肌交界处多点注射0.2 mL无血清M199培养液;移植组:造模后将体外培养2周的大鼠自体卫星细胞0.2 mL以注射的方式移植到大鼠梗死区周围.假手术组:不造模,仅在左前降支周围心前壁多点注射0.2 mL生理盐水.主要观察指标:4周后测定各组大鼠缺血心肌血管内皮生长因子mRNA、血管内皮生长因子蛋白质的表达,缺血心肌毛细血管密度变化,苏木精伊红染色观察各组心肌细胞在梗死区的生长、增殖情况.结果:①卫星细胞移植4周后,假手术组和心肌梗死组血管内皮生长因子mRNA和血管内皮生长因子蛋白表达较移植组明显降低(P<0.01);心肌梗死组大鼠毛细血管密度较假手术组升高(P<0.05);移植组大鼠缺血心肌中毛细血管密度较假手术组、心肌梗死组亦明显升高(P<0.01).②苏木精-伊红染色显示假手术组大鼠心肌形态正常,结构清晰,心肌纤维排列整齐有序,肌纤维间无成纤维细胞聚集、增生现象.心肌梗死组大鼠心肌内可见成纤维细胞增生及胶原形成,心肌有序的基本结构发生紊乱.移植组大鼠其梗死区可见较多带有横纹且具有多核的肌细胞存在,组织排列较有序,纤维组织明显少于心肌梗死组.结论:卫星细胞在心肌梗死区中可增殖分化为具有弹性和收缩功能的横纹肌样细胞,并通过自分泌和旁分泌的形式分泌血管内皮生长因子促使缺血心肌毛细血管增生,从而有效地抑制了缺血心肌的纤维化进程.     

大鼠自体骨骼肌卫星细胞移植治疗心肌梗死后血清血管内皮生长因子的改变及其意义

目的:了解自体骨骼肌卫星细胞移植治疗大鼠心肌梗死后血清血管内皮生长因子(vascularendothelialgrowthfactor,VEGF)的改变及临床意义。方法:30只Wistar大鼠随机分为移植组(n=15)及对照组(n=15),所有大鼠经结扎冠状动脉前降支建立心肌梗死模型。将体外培养2周的大鼠自体卫星细胞以注射的方式移植到梗死区周围,4周后病理观察移植细胞的生长、增殖情况及缺血心肌毛细血管密度的改变,并测定血清VEGF浓度及血流变参数的改变。结果:卫星细胞在梗死区中可增殖分化为横纹肌纤维,与对照组相比,移植组的缺血心肌毛细血管密度犤(523.42±82.14)和(430.73±65.04)/mm2,t=2.98,P<0.01犦、血清VEGF质量浓度明显增高犤(320.05±39.29)和(271.14±37.52)μg/L,t=2.37,P<0.05犦,而某些血液流变参数明显改善犤低切全血黏度:(11.09±1.52)和(13.02±1.56)mPa·s,t=2.22,P<0.05;红细胞聚集指数:7.59±0.81和8.56±0.59,t=3.25,P<0.01;卡松黏度:(1.64±0.41)和(2.26±0.41)mPa·s,t=3.66,P<0.01;卡松屈服应力:(11.23±1.54)和(12.69±1.59)Pa,t=2.23,P<0.05犦。结论:卫星细胞在心肌梗死区中可增殖分化为横纹肌样细胞,并通过自分泌和旁分泌的形式提高血清VEGF浓度,由此改善血流变参数及缺血心肌毛细血管密度。     

自体骨骼肌卫星细胞心肌移植对心肌梗死大鼠心室重构的影响

目的:了解自体骨骼肌卫星细胞心肌移植对心肌梗死大鼠心室重构的影响及可能机制。方法:实验于2004-03/06在第三军医大学大坪医院野战外科研究所三室完成。45只Wistar大鼠随机分为3组,假手术组、对照组及移植组,每组各15只。①对照组及移植组大鼠经结扎冠状动脉前降支建立心肌梗死模型;假手术组除不结扎左前降支外,其余操作同对照组和移植组。②将体外培养2周的大鼠自体卫星细胞以注射的方式移植到移植组大鼠梗死区周围。③4周后测定各组大鼠心室质量及质量指数、血管内皮生长因子mRNA及血管内皮生长因子蛋白质的表达、缺血心肌毛细血管密度的变化,同时观察移植细胞在梗死区的生长、增殖情况并探讨它们相互的关系。结果:45只大鼠,实验中假手术组及移植组死亡3只,对照组死亡4只,进入结果分析35只。①卫星细胞在梗死区中可增殖分化为横纹肌纤维。②卫星细胞移植4周后,移植组及对照组左室质量、右室质量、左室质量指数(左室质量/体质量)及右室质量指数(右室质量/体质量)比假手术组均明显增加[左室质量:(621.25±25.34),(699.82±47.38),(550.33±21.47)mg,P<0.001,0.001;右室质量:(192.92±26.83),(219.82±38.23),(160.08±19.63)mg,P<0.01,0.001;左室质量指数:(2.36±0.20),(2.69±0.07),(2.12±0.05)mg/g,P<0.001,0.001;右室质量指数:(0.73±0.09),(0.84±0.11),(0.61±0.02),P<0.001,0.001];移植组左室质量、左室质量指数及右室质量指数比对照组明显减低(P<0.001,0.001,0.01)。③移植组大鼠缺血心肌中毛细血管密度及血管内皮生长因子mRNA、血管内皮生长因子蛋白质的表达较之假手术组、对照组亦明显升高[(523.42±82.14),(378.23±43.16),(430.73±65.04)n/mm2,P<0.001,0.01;1.601±0.251,0.582±0.066,0.590±0.072,P<0.001,0.001;0.148±0.030,0.110±0.012,0.117±0.014,P<0.001,0.01]。结论:卫星细胞在心肌梗死区中可增殖分化为具有弹性和收缩功能的横纹肌样细胞,并通过自分泌和旁分泌的形式增加血管内皮生长因子的表达,促使缺血心肌毛细血管增生,从而抑制心室重构过程。     

去铁胺对急性心肌缺血大鼠心肌血管新生及血管内皮生长因子表达的影响

目的:探讨去铁胺(DFO)对急性心肌缺血大鼠心肌梗死面积、心肌血管新生及心肌组织血管内皮生长因子(VEGF)表达的影响.方法:健康SD大鼠随机分为4组:正常对照组(Nor组)、假手术组(Sham组)、心肌梗死+生理盐水组(MI组)、心肌梗死+DFO组(DFO组).开胸手术结扎冠状动脉前降支制作心肌梗死模型(Sham组只穿线不结扎),DFO组和MI组术前24 h分别给予DFO (200 mg/kg)或等体积生理盐水腹腔注射.TTC染色后检测心梗面积;RT-PCR检测梗死边缘区心肌VEGF的表达;免疫组化法检测梗死边缘区心肌微血管密度及VEGF蛋白的表达.结果:DFO组心梗面积明显低于MI组,梗死边缘区微血管密度高于MI组、Sham组和Nor组.MI组心肌组织VEGF蛋白表达明显比Nor组和Sham组高;DFO组心肌组织VEGF蛋白比MI组表达进一步上调.VEGF mRNA的表达与VEGF蛋白表达变化一致.结论:DFO可以减少急性心肌缺血大鼠心梗面积,促进缺血区域血管新生,其作用机制与上调VEGF的表达有关.     

大鼠自体骨骼肌卫星细胞移植治疗心肌梗死后血清血管内皮生长因子的改变及其意义

目的：了解自体骨骼肌卫星细胞移植治疗大鼠心肌梗死后血清血管内皮生长因子(vascular endothelial growth factor，VEGF)的改变及临床意义。方法：30只Wistar大鼠随机分为移植组(n=15)及对照组(n=15)，所有大鼠经结扎冠状动脉前降支建立心肌梗死模型。将体外培养2周的大鼠自体卫星细胞以注射的方式移植到梗死区周围，4周后病理观察移植细胞的生长、增殖情况及缺血心肌毛细血管密度的改变，并测定血清VEGF浓度及血流变参数的改变。结果：卫星细胞在梗死区中可增殖分化为横纹肌纤维，与对照组相比，移植组的缺血心肌毛细血管密度[(523．42&;#177;82．14)和(430、73&;#177;65．04)／mm^2，t=2．98，P&;lt;0．01]、血清VEGF质量浓度明显增高[(320．05&;#177;39．29)和(271．14&;#177;37．52)μg／L，t=2．37，P&;lt;0．05]，而某些血液流变参数明显改善[低切全血黏度：(11．09&;#177;1．52)和(13．02&;#177;1．56)mPa&;#183;s，t=2．22，P&;lt;0．05；红细胞聚集指数：7．59&;#177;0．81和8．56&;#177;0．59，t=3．25，P&;lt;0．01；卡松黏度：(1．64&;#177;0．41)和(2．26&;#177;0．41)mPa&;#183;s，t=3．66，P&;lt;0．0l；卡松屈服应力：(11．23&;#177;1．54)和(12．69&;#177;1．59)Pa，t=2．23，P&;lt;0．05]。结论：卫星细胞在心肌梗死区中可增殖分化为横纹肌样细胞，并通过自分泌和旁分泌的形式提高血清VEGF浓度，由此改善血流变参数及缺血心肌毛细血管密度。     

可降解材料纤维蛋白胶介导血管内皮细胞生长因子对心肌梗死组织血管再生的影响

背景：血管内皮细胞生长因子（vascular endothelial growth factor,VEGF）可促进梗死心肌血管再生,但经系统性静脉灌注来传递VEGF是无效的,反复直接心肌注射会损伤正常心肌结构。目的：验证通过可降解材料纤维蛋白胶将VEGF移植到心肌梗死及缺血区域促进血管再生的可行性,并观察大鼠心功能的变化。设计、时间及地点：随机对照动物实验,于2007-01/2008-04在新疆医科大学第一附属医院冠心病VIP实验室完成。材料：树脂色谱法纯化获得重组蛋白VEGF121,与纤维蛋白胶结合得到VEGF纤维蛋白胶。9周龄雄性SD大鼠28只,其中13只节扎冠状动脉左前降支制备心肌梗死模型为心肌梗死组,其余15只仅打开心包,不节扎左前降支者为为非心肌梗死组。方法：心肌梗死组梗死即刻将空白或VEGF纤维蛋白胶移植到梗死区域,附着在梗死和缺血区;非心肌梗死组将空白或VEGF纤维蛋白胶附在相应的左室前壁,另有3只不处理做为对照。主要观察指标：移植4周后经心脏超声行心功能检测,然后麻醉处死大鼠,取出心脏行免疫组化及血管测量分析。结果：移植VEGF胶后,非心肌梗死和心肌梗死组大鼠的毛细血管密度显著高于空白胶组（P〈0.001）;心肌梗死组梗死附近缺血区毛细血管密度显著高于间隔区（P〈0.01）。移植VEGF胶后,大鼠心功能有改善的趋势,但差异无显著性意义（P=0.2482）,结论：通过可降解材料移植VEGF可使大鼠非心肌梗死区和心肌梗死心肌区的毛细血管明显增生;将纤维蛋白胶作为传递血管再生因子到心肌的介质是可行的。     

自体骨髓干细胞动员联合生长激素治疗大鼠急性心肌梗死

目的 粒细胞集落刺激因子（G—CSF）单用或合用重组人生长激素（rhGH）动员急性心肌梗死大鼠自体骨髓干细胞，观察梗死区心肌和血管再生状况。方法 液氮冷冻法制备心肌梗死模型。动物随机分为正常动员组（N，n=8）、假手术组（SO，n=6）、梗死组（MI，n=8）、G—CSF治疗组（G，n=8）、rhGH治疗组（GH，n=8）和G—CSF＋rhGH治疗组（GG，n=8）。计数动员前后白细胞计数（WBC）及单个核细胞百分比（MNC％）；术后4周处死动物，取心脏称重，行苏木素-伊红（HE）染色及免疫组化染色。结果 ①N组及G组动员后WBC和MNC％较动员前均明显增加（P均〈0．01）。MI组动员后WBC明显高于动员前（P〈0．01），但MNC％与动员前比较差异无显著性（P〉0．05）。G组动员后WBC和MNC％均显著高于MI组动员后（P均〈0．05）。②MI、G、GH、GG4组间梗死面积无明显差别（P〉0．05）。③GH、GG组动物处死时体重和心脏重量均明显高于SO、MI和G组（P均〈0．05）。GG组心脏重量／体重比高于SO、MI和G组（P〈0．05）。①G、GH和GG组毛细血管计数明显多于MI、SO组，GG组多于G、GH组（P均〈0．01）。⑤G、GH和GG组均可见BrdU（＋）新生细胞，部分形成新生毛细血管；G、GG组还可见新生心肌样细胞。结论 ①G—CSF可动员正常和心肌梗死后大鼠自体骨髓干细胞到外周血循环并进入梗死区，使大鼠梗死区心肌样细胞及毛细血管再生。②rhGH可促进梗死区毛细血管新生，但不再生心肌样细胞。③G—CSF联合rhGH治疗使大鼠梗死区毛细血管密度明显增加，提示两药合用有相加作用。     

三脉血注射液对急性心肌梗死大鼠VEGFbFGF的影响

目的研究中药三脉血注射液对急性心肌梗死大鼠VEGF、bFGF的影响及其促血管新生作用。方法取健康Wistar大鼠50只,雌雄各半,体质量200～250 g,随机分为四组:假手术组(A组),生理盐水对照组(B组),三脉血大剂量组(C组),三脉血小剂量组(D组),14 d后处死动物,进行免疫组化检测梗死-非梗死交界处区VEGF、bFGF表达,并于显微镜下观察其毛细血管数。结果与B组相比C、D组VEGF、bFGF表达增加(P<0.05),毛细血管数增加(P<0.05);C组和D组相比,VEGF、bFGF表达及毛细血管数量差异无统计学意义(P>0.05)。结论三脉血注射液可以促进急性心肌梗死大鼠缺血心肌分泌VEGF、bFGF,并促进毛细血管生成,发挥心肌保护作用。     

同种异体骨髓间质干细胞移植联合VEGF基因转染治疗心肌梗死的实验研究

目的：探讨同种异体骨髓间质千细胞（BMSCs）移植联合血管内皮生长因子（VEGF）基因转染对大鼠急性心肌梗死血管再生和心功能的影响：方法：体外分离、纯化、培养大鼠BMSCs，以BrdU标记细胞；制备、抽提、纯化质粒PAdTrack／VEGF165。结扎冠状动脉建立急性心肌梗死模型2周后，随机将其分为4组（n=12），进行心肌内BMSCs移植和／或VEGF165转染，组Ⅰ：BMSCs移植＋VEGF165转染；组Ⅱ：BMSCs移值；组Ⅲ：VEGF165转染；组Ⅳ：DMEM注射作为对照组。4周后行免疫组化和超声心动图检查：结果：组Ⅰ和组Ⅱ梗死及缺血心肌处可见大量BrdU标记的移植细胞，其中缺血心肌处部分移植细胞分化为血管内皮细胞并形成新生毛细血管。Ⅷ因子染色阳性的新生血管密度分布为组Ⅰ〉组Ⅲ〉组Ⅱ〉组Ⅳ（P均〈0．01）。细胞移植和基因转染治疗后室壁厚度和室壁运动幅度改善，EF值增加幅度（△EF）组Ⅰ〉组Ⅱ〉组Ⅲ〉组Ⅳ（P均〈0．01）：结论：同种异体骨髓间质干细胞移植联合VEGF基因转染能进一步增强大鼠梗死缺血区血管再生、改善室壁厚度和心功能，有利于心肌梗死后的康复。     

不同种类自体骨髓干细胞移植对梗死心肌左室重构的效果比较

背景:骨髓干细胞移植可改善心功能、预防心室重构,目前用于移植的成体骨髓干细胞有骨髓单个核细胞、骨髓间充质干细胞和内皮祖细胞等,不同种类的骨髓干细胞移植后的效果及具体机制尚不清楚。目的:比较自体骨髓单个核细胞、骨髓间充质干细胞冠状动脉移植对急性心肌梗死后心室重构的影响。设计、时间及地点:随机对照动物实验,于2005-03/2006-12在河北省人民医院临床研究中心、河北医科大学电镜室及大连宝生物进行。(basic fibroblast growth factor,bFGF)材料:36只冀中白猪随机分为4组:假手术组6只、模型组10只、骨髓单个核细胞组10只、骨髓间充质干细胞组10只。方法:采用梯度密度离心法分离培养猪自体骨髓单个核细胞,以贴壁法分离培养猪自体骨髓间充质干细胞,移植前均行胶体金标记。除假手术组外,其余3组均以球囊导管压迫冠状动脉前降支的方法建立猪急性心肌梗死模型。造模后90min,经导管由冠状动脉腔内骨髓单个核细胞组移植自体骨髓单个核细胞(6.0±1.3)×107个,骨髓间充质干细胞组移植自体骨髓间充质干细胞(4.5±2.1)×107个,培养28d。主要观察指标:光镜及电镜观察心肌组织病理学改变;超声检查心功能变化;免疫组织化学检测心肌血管数、心肌细胞凋亡、心肌组织核因子κB及肌钙蛋白I阳性表达情况,及其与心功能的关系;RT-PCR法检测心肌血管内皮生长因子(vascular endothelial growth factor,VEGF)、碱性成纤维细胞生长因子(basic fibroblast growth factor,bFGF)mRNA的表达,及其与心功能的关系。结果:①骨髓间充质干细胞组在梗死区、梗死边缘区均可见大量血管增生,冠脉血管周围可见异常细胞团生长,骨髓单个核细胞组有较多的毛细血管"芽生"现象。②细胞移植前各组心功能指标基本相似(F=1.550,P>0.05)。移植后28d与模型组比较,其余3组左心室射血分数均明显降低(F=5.30,P<0.05)。③与模型组比较,骨髓单个核细胞组梗死区及梗死边缘区的血管数明显增加(F=29.56～34.87,P<0.01),骨髓间充质干细胞组无变化;移植细胞两组的梗死区、梗死边缘区心肌细胞凋亡率均显著降低(F=14.31～35.34,P<0.01),肌钙蛋白I阳性率均明显升高(F=19.05,P<0.01);梗死边缘区核因子кB阳性率均明显降低(F=19.05,P<0.01)。④骨髓单个核细胞组梗死边缘区VEGF基因的表达显著高于模型组、骨髓间充质干细胞组(F=49.41,P<0.01)。骨髓间充质干细胞组梗死边缘区bFGF基因的表达显著高于模型组、骨髓单个核细胞组(F=4.71,P<0.01)。⑤左室射血分数与心肌细胞凋亡率、心肌核因子κB呈负相关(r=-0.4411,P<0.05;r=-0.5796,P<0.01);与血管数、VEGF及bFGF表达呈正相关(r=0.775,P<0.01;r=0.5651,P<0.05;r=0.5735,P<0.05)。结论:经冠脉自体骨髓单个核细胞或骨髓间充质干细胞移植均可减轻心肌梗死后左心室重构,心功能的改善与干细胞移植后增加心肌血管数量及心肌VEGF,bFGF表达、减少心肌细胞凋亡及核因子κB水平有关。骨髓单个核细胞移植促心肌血管增生及VEGF的表达均优于骨髓间充质干细胞,而后者促bFGF基因表达的作用优于前者。     

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.     

Clinical Pharmacokinetics of Morphine

Morphine, the most widely used mu-opioid analgesic for acute and chronic pain, is the standard against which new analgesics are measured. A thorough understanding of the pharmacokinetics of morphine is required in order to safely and effectively use this analgesic in a wide variety of patients with different levels of organ function. A MEDLINE search was conducted to identify literature published between 1966 and January 2002 relevant to the pharmacokinetics of morphine. These publications were reviewed and the literature summarized regarding unique and clinically important elements of morphine disposition relative to its parenteral administration (including intravenous, intramuscular, subcutaneous, epidural and intrathecal administration), absorption profile (immediate release, controlled release, and sublingual/buccal, and rectal administration), distribution, and its metabolism/ excretion. Special populations, including infants, elderly, and those with renal/liver failure, have a unique morphine pharmacokinetic profile that must be taken into account in order to maximize analgesic efficacy and reduce the risk of adverse events.