蛛网膜下腔移植SPIO标记的MSCs在大鼠脊髓损伤模型的MR活体示踪研究

目的 将超顺磁性氧化铁纳米粒子(SPIO)标记的骨髓间充质干细胞BMSCs通过蛛网膜下腔置管移植到脊髓损伤大鼠模型,以磁共振成像(MRI)观察其迁移和分布.方法 用携带绿色荧光蛋白的腺病毒(AD5/F35-EGFP)和SPIO标记分离纯化后的BMSCs,免疫荧光和普鲁士蓝染色显示标记效果.制作大鼠脊髓损伤模型,并将蛛网膜下腔置管成功的10只SD大鼠随机分为2组,将标记细胞(实验组,n＝5)和未标记细胞(对照组,n＝5)经蛛网膜下腔移植到模型鼠.在移植前、移植后3、7、14天用3T MRI对移植细胞进行活体示踪,并与损伤脊髓组织切片GFP表达进行对照.结果 AD5/F35-EGFP和SPIO可以高效地标记BMSCs,标记细胞表达绿色荧光,普鲁士蓝染色显示BMSCs胞质内出现蓝色铁颗粒,标记对细胞增殖活力没有明显的影响.蛛网膜下腔移植标记细胞到大鼠脊髓损伤模型,MRI显示损伤区域逐渐增强的T2低信号,组织切片荧光检查与MRI结果一致,未标记细胞组MRI无明显低信号改变.结论 SPIO纳米颗粒可有效标记BMSCs.蛛网膜下腔移植的BMSCs可迁移到脊髓损伤区域;利用MRI可对移植细胞进行活体示踪.     

体外磁标记骨髓基质细胞移植治疗大鼠创伤性脑损伤的在体MRI观察

目的 采用高场MR在体监测超顺磁性氧化铁颗粒(SPIO)标记大鼠骨髓基质细胞(BMSCs)在脑损伤模型大鼠脑内的分布与迁移.方法 首先进行BMSCs体外培养,然后采用SPIO标记BMSC;采用Feeney法制作创伤性脑损伤模型(TBI).脑损伤24 h后于损伤区周围立体定向移植BMSCs,并于移植后1、3天及1、3周行MR检查.结果 倒置相差显微镜下观察,标记BMSCs的细胞内含有棕黄色铁颗粒,普鲁士蓝染色呈阳性;电镜下胞浆内可见散在分布的铁颗粒.细胞移植后MRI可见移植部位在MR各序列上均呈点状低信号,尤以磁敏感加权成像(SWI)上显示明确.结论 高场MRI能够在活体内连续示踪观察SPIO标记的BMSCs的分布与迁移,且SWI序列最为敏感.     

MRI活体示踪大鼠脑内超顺磁性氧化铁标记成人神经干细胞

背景:目前判断神经干细胞移植后向脑损伤部位的迁移需要处死受体动物行脑切片检查,且不能进行多点、动态的观察.目的:探讨用MRI活体示踪移植磁化标记成人神经干细胞在创伤性脑损伤模型大鼠脑内迁移和分布的可行性.方法:建立大鼠脑部左侧半球创伤性脑损伤模型,超顺磁性氧化铁体外标记成人神经干细胞.模型建立后2周将标记成人神经干细胞立体定向移植入大鼠脑部右侧半球.在移植后1 d、3 d、1周和2周分别行大鼠头部MRI.2周后处死大鼠取脑,用普鲁士蓝染色法进行染色,观察标记神经干细胞的迁移.结果与结论:超顺磁性氧化铁体外标记成人神经干细胞的成功率约为85%.移植后行头颅MRI可见位于右侧半球的移植部位FSE T2WI和GRE T2序列呈环形低信号.随时间推移,创伤性脑损伤后移植标记干细胞组大鼠头颅MRI可见脑内有一低信号线,指向对侧脑挫伤部位,而创伤性脑损伤后移植未标记干细胞组,正常大鼠移植标记干细胞组无信号线.MRI显像结果与脑切片普鲁士蓝染色观察到的结果是相符合的.结果提示用MRI活体示踪移植磁化标记成人神经干细胞在创伤性脑损伤模型大鼠脑内迁移和分布可行、有效.     

SPIO标记BMSCs移植治疗局灶性脑梗死的MRI示踪研究

目的通过采用磁共振技术示踪在体超顺磁性氧化铁(super paramagnetic iron oxide,SPIO)标记骨髓间充质干细胞(bone marrow mesenchymal stem cells,BMSCs),观察SPIO标记的BMSCs在局灶性脑梗死模型中的迁移及治疗情况。材料与方法 28只雄性SD大鼠随机分为正常对照组(CON,n=4)、假手术组(SHAM,n=4)、局灶性脑梗死对照组(MCAO+SPIO,n=10)和SPIO标记BMSCs治疗组(MCAO+SPIO-BMSC,n=10)。通过普鲁士蓝染色法及CCK8法选取SPIO标记BMSCs的最佳浓度,并使用立体定向注射方法进行最佳浓度SPIO及SPIOBMSC的移植,术后第1、9、20、30、43天行1.5 T MRI扫描,检测两者在局灶性脑梗死中的生物学行为,普鲁士蓝染色观察细胞迁移分布情况。结果当SPIO标记浓度为50μg/ml时,BMSCs普鲁士蓝染色效率为100%,CCK8检测增殖活性较对照组及75μg/ml组均有明显差异(P0.05)。使用T2WI和SWI序列均能明确检测到MCAO+SPIO组和MCAO+SPIO-BMSC组中移植区域信号减低。与T2WI序列相比,SWI序列显示低信号范围更广,示踪时间更长。与MCAO+SPIO组比较,MCAO+SPIO-BMSC组可见SPIO标记的BMSCs向缺血梗死区迁移。普鲁士蓝染色检查发现:普鲁士蓝染色阳性的细胞聚集在梗死区域周围。结论MRI技术能够有效示踪50μg/ml SPIO标记的BMSCs,显示BMSCs在局灶性脑梗死模型中随时间变化发生的生物学行为,并对BMSCs在局灶性脑梗死中的迁移治疗情况进行动态观测。     

超顺磁性氧化铁纳米粒子标记心脏内骨髓间充质干细胞及活体磁共振示踪的实验研究

目的:探讨超顺磁性氧化铁纳米粒子(superparamaganetic iron oxide nanoparticles,SPIO)能否作为示踪剂在磁共振下对移植入梗死边缘区的骨髓间充质干细胞(mesenchymal stem cells,MSCs)进行体内追踪。方法:体外培养MSCs用SPIO标记后普鲁士蓝染色观察标记率及MTT法观察其对MSCs活性的影响。建立大鼠急性心肌梗死模型,分磁性细胞移植组、非磁性细胞移植组、纳米粒子移植组,分别于梗死心肌边缘区多点注射SPIO标记MSCs、未标记MSCs、SPIO。术后3、7、14、21d行MRI检查后处死大鼠,进行组织学检查。结果:SPIO标记MSCs阳性率达95%,对MSCs的活性和分化无明显影响。磁性细胞移植组术后3、7、14d在MRT2像显示的低信号注射点为65.6%、56.3%、18.8%,术后21d不能显示注射点。随时间的延长,低信号区域边界模糊,范围扩大,信号对比度降低。结论:SPIO可以作为示踪剂在磁共振下对移植入大鼠梗死边缘区的MSCs进行体内追踪,该方法能够作为一种无创的手段来示踪体内干细胞的迁移及转归。     

SPIO标记脂肪干细胞移植治疗大鼠脑梗死的磁共振示踪成像研究

目的通过采用多聚左旋赖氨酸（PLL）与超顺磁氧化铁纳米微粒（SPIO）的复合物对脂肪干细胞（ADSCs）体外进行标记,观察SPIO标记ADSCs脑内移植治疗大鼠脑梗死的分布和迁徙情况。方法显微镜下直接结扎大脑中动脉方法制备大鼠脑梗死模型36只,随机分成缺血未干预对照组（12只）、磁性标记ADSCs移植组（12只）和未磁性标记ADSCs移植组（12只）,采用立体定向方法脑内移植。对移植后大鼠的神经系统行为和运动功能进行评估,病理组织化学染色观察ADSCs在体内的分布情况,并用磁共振成像的方法在体观察ADSCs的分布,并与病理结果进行对比。结果移植后3周神经系统行为学评分显示移植组动物明显改善,ADSCs脑内移植后3周MRT2WI显示移植区低信号改变并通过胼胝体向病灶迁移。病理组织检查显示磁共振低信号改变区可见普鲁士蓝染色阳性细胞。结论移植ADSCs可以有效地促进大鼠脑梗死后神经行为功能的恢复,MRI可用于在体评价经SPIO和PLL复合物标记的ADSCs细胞移植后在体内的分布、迁移过程。     

超顺磁性氧化铁标记骨髓间充质干细胞移植治疗兔脊髓损伤的磁共振活体示踪

目的通过蛛网膜下腔置管,将超顺磁性氧化铁(SPIO)标记后的骨髓间充质干细胞(MSCs)移植入兔脊髓损伤模型,观察脊髓损伤MR活体示踪移植细胞的可行性。方法制作兔SCI模型,并在蛛网膜下腔置管以备移植。将实验用大白兔随机分为三组:A组为移植SPIO标记细胞;B组为移植未标记细胞;C组不移植细胞只注射PBS液做对照组。在细胞移植后3d、7d、14d、21d,进行MR活体示踪,并做病理学检测进行对照。结果 SPIO标记的MSCs移植入脊髓损伤模型后7d,MR扫描的T2WI上脊髓损伤区域出现点状低信号影;14d后T2WI上脊髓损伤区域的点状低信号影增多,21d后T2WI上脊髓损伤区域的点状低信号影减少。脊髓损伤区域组织切片行普鲁士蓝染色,发现局部组织上出现大量含蓝色铁颗粒的细胞,其细胞变化规律与MR示踪结果一致。结论蛛网膜下腔移植的SPIO标记MSCs可定向迁移到脊髓损伤区域,利用MR可对移植细胞进行活体示踪。     

超声新技术预测心脏再同步化治疗疗效的动物实验和临床研究

目的 采用高场MR在体监测超顺磁性氧化铁颗粒(SPIO)标记大鼠骨髓基质细胞(BMSCs)在脑损伤模型大鼠脑内的分布与迁移。方法 采用Feeney法制作大鼠脑外伤(TBI)模型,然后平均分为4组:A 组:TBI后移植SPIO 标记BMSCs;B组:TBI后移植单纯SPIO;C组:TBI后移植未标记BMSCs;D组:TBI后移植培养液。其中,A组为实验组,其余均为对照组。①SPIO 标记:将1μl的SPIO(Resovist)加入2ml培养基混匀,使其终浓度为35μg/ml;然后将P6代细胞消化离心后加入上述加有SPIO 的培养基混匀;37℃、5% CO₂ 条件下共同孵育。②细胞内铁颗粒的鉴定:采用细胞普鲁士蓝染色法,将贴壁干细胞去除培养液后以磷酸盐缓冲液(PBS)冲洗,4%戊二醛固定30min,蒸馏水冲洗3次,2%亚铁氰化钾-6%盐酸水溶液孵育30min,1%核固红复染3min,蒸馏水洗去多余的核固红,显微镜下观察。③细胞移植:TBI模型鼠建立后24h进行立体定向移植手术。模型鼠用10%水合氯醛0.32ml/100g体质量腹腔注射再次麻醉后,俯卧位保定于立体定向架上,损伤顶叶皮层接受细胞移植。移植位点位于左顶叶TBI周围皮质(前囟后3mm,旁开2mm,深5mm),垂直距离以硬脑膜为标准。A组移植SPIO 磁化标记的BMSCs;B组仅移植等量等浓度的SPIO;C组移植等量等浓度的未标记BMSCs;D组仅移植等量的培养液。取10μl细胞(约0.5×10⁶ 个)悬液或对照液5min内注射,留针5min,然后缓慢拨出注射针头。移植完毕缝合头皮,腹腔注射庆大霉素2000U 抗菌治疗,回笼饲养。于移植后第1、3天及1、3周对各组实验动物行MR 扫描。结果 SPIO 标记后的BMSCs在倒置显微镜下可见细胞质内有黄色铁颗粒。行普鲁士蓝染色后,标记BMSCs胞质内可见阳性蓝色颗粒。透射电镜下胞浆内可见许多散在的铁颗粒。A组在各个时间点均可见位于左侧半球的移植部位在T1WI、T2WI、T2^* WI及磁敏感加权成像(SWI)序列上呈类圆形点状低信号,以T2^* WI及SWI序列的敏感度、对比度明显,SWI最明显(图3B);B组仅在移植后1天接受MR检查,呈低信号,3天及以后MR检查可见低信号消失;C、D两组在各个时间点均未见显示。A组动物左侧顶叶皮质的类圆形点状低信号在3天、1周及3周逐渐向损伤区迁移,尤其在SWI序列上显示更清楚。结论 高场MRI能够在活体内连续示踪观察SPIO 标记的BMSCs的分布与迁移,且以SWI序列最为敏感。     

面神经损伤大鼠脑内移植绿色荧光蛋白转基因胎鼠神经干细胞的成活及迁移

背景:目前面神经损伤后的修复主要集中在外周神经干,但面神经损伤后会导致部分中枢运动神经元凋亡.现阶段关于干细胞植入面神经损伤大鼠脑后对面神经核团内凋亡神经元的影响相关报道甚少.目的:观察大鼠面神经损伤后,脑内移植绿色荧光蛋白转基因胎鼠的神经干细胞的成活和迁移情况.设计、时间及地点:随机对照动物实验,于2008-07/12在昆明医学院神经科学研究所完成.材料:孕14～16d的绿色荧光蛋白转基因蛋白小鼠1只,用于制备转基因神经干细胞.清洁级SD雄性大鼠24只,随机分为3组:面神经损伤转基因细胞组12只、面神经损伤细胞培养液组6只、面神经正常转基因细胞组6只.方法:面神经损伤转基因细胞组、面神经损伤细胞培养液组大鼠建立面神经切断模型.造模后1周,行转基因神经干细胞立体定向移植,注射点为前囟后方11.30 mm、背侧9.00 mm、正中线位置.面神经损伤转基因细胞组、面神经正常转基因细胞组各注入10 μ L转基因神经干细胞悬液(含5×106个细胞),面神经损伤细胞培养液组注入10 μL神经干细胞培养液,4周后制作脑组织冰冻切片.主要观察指标:荧光显微镜观察移植部位绿色荧光蛋白阳性神经干细胞的存活情况,及其向损伤侧面神经核团周围迁移的情况.结果:①移植处:面神经损伤转基因细胞组、面神经正常转基因细胞组均可见数量不等的绿色荧光蛋白阳性细胞,其中部分绿色荧光蛋白阳性细胞位于血管内;面神经损伤细胞培养液组未见绿色荧光蛋白阳性细胞.②面神经核团周围:仅面神经损伤转基因细胞组可见数量不等的绿色荧光蛋白阳性细胞迁移于损伤侧面神经核团周围,而健侧面神经核周围未见绿色荧光蛋白阳性细胞;余2组双侧面神经核周围均未见绿色荧光蛋白阳性细胞.③移植处与面神经核团周围之间:未见绿色荧光蛋白阳性细胞相连.结论:神经干细胞移植入面神经损伤大鼠脑内后,可以向损伤侧面神经核周围迁移.     

心脏MRI在体示踪移植细胞的可行性研究

目的：寻找一种能够对移植细胞进行在体示踪的标记方法,为细胞移植的动物和临床实验中细胞的存留、迁移提供重要手段。方法：从中华小型猪髂骨处抽取骨髓,体外培养扩增MSCs。将SPIO和MSCs共同孵育培养36h。普鲁士蓝染色评价细胞的标记效率;通过MTT比色实验评价SPIO对细胞生长能力的影响;台盼蓝染色检验标记后细胞的活性;使用Costar Transwell方法评价铁离子对细胞迁移能力的影响;用细胞分化诱导液培养标记后的细胞评价其向成脂肪细胞和成骨细胞的分化能力。在体内实验中将SPIO标记或未标记的自体MSCs注射到心肌或冠状动脉内,通过心脏磁共振检查对移植细胞进行在体示踪观察。在细胞移植后不同时期取材动物心脏切片进行普鲁士蓝染色观察移植细胞。结果：MSCs经铁离子标记后普鲁士蓝染色阳性率在98%以上,可见蓝染颗粒位于细胞浆内,标记细胞电镜切片观察可见高密度铁颗粒位于细胞浆内。MTT比色实验发现随着培养液中SPIO浓度的增加细胞增殖能力没有明显改变;台盼蓝染色显示标记后98％的细胞保持活性;细胞经SPIO标记后仍可保持原有的细胞形态,可继续培养、传代。细胞迁移试验发现细胞标记后对SDF-1和VEGF诱导的迁移能力没有明显的减低。铁离子标记后细胞仍可向成脂肪细胞和成骨细胞分化。注射到心肌或冠状动脉内的SPIO标记的MSCs可通过心脏磁共振检查进行在体示踪,动态观察显示SPIO标记细胞在磁共振影像上表现为低密度灶影或信号缺失,并且在移植后4周仍可显影。病理学检查可以看到移植细胞呈普鲁士蓝染色阳性,并和影像学有很好的一致性。结论：临床使用的SPIO磁共振对比剂可以安全、有效的标记MSCs。利用心脏磁共振对移植的标记细胞可以实现移植细胞的在体示踪观察。此标记方法结合心脏磁共振技术为移植细胞的在体示踪和细胞存留、迁移的研究提供了良好的手段。     

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.