超声心动图在倍频Nd:YAG/532激光心肌血运重建术实验研究中的应用

目的　应用超声心动图技术评价倍频Nd :YAG/5 3 2 (KTP)激光心肌血运重建术 (TMLR)对急性心肌梗死犬心脏功能的影响。方法　家犬 12条 ,随机分为TMLR组和对照组 ,每组 6条 ,结扎左前降支中段 ,造成急性心肌梗死犬模型 ,TMLR组在梗死区以KTP激光行TMLR。术后动物饲养 2～ 3月 ,以超声心动图经体表检测左室射血分数 (EF)、左室短轴缩短率 (FS)、室壁运动指数 (WMSI)、心输出量 (CO)作为左室收缩功能的指标。测量二尖瓣口舒张早期和舒张晚期血流速率 (Ve ,Va)及E/A作为左室舒张功能的指标。以局部室壁收缩增厚率 (ΔT)和心肌运动速率 (S、E和A峰 )代表梗死局部心肌的功能。结果超声心动图检查发现 ,反映动物心脏整体收缩功能和整体舒张功能的指标两组之间比较差异均无显著意义 (均P >0 .0 5 ) ;而反映梗死区局部收缩和舒张功能的指标 ,TMLR组明显好于对照组 ,两组之间差异有显著性意义 (均P <0 .0 5 )。结论　KTP激光TMLR对梗死局部心肌功能有改善作用 ,但对心脏整体功能则无明显作用     

负荷超声心动图检测KTP激光心肌血运重建术后心肌存活性

目的　研究KTP激光心肌血运重建术 (TMLR)对梗死局部心肌存活性的影响。方法　家犬 12只 ,随机分为TM LR组和对照组 ,每组 6只 ,结扎左前降支中段 ,造成急性心肌梗死犬模型 ,TMLR组在梗死区以KTP激光行TMLR。术后动物饲养 2～ 3个月 ,采用多巴酚丁胺负荷超声心动图 ,检测心肌的存活性。结果　负荷超声心动图检查发现 ,TMLR组给予5 μg/(kg·min)多巴酚丁胺后室壁收缩增厚率、室壁运动幅度和室壁运动速度均有不同程度的改善 ,但当多巴酚丁胺剂量增大到 10 μg/(kg·min) ,前壁的室壁收缩增厚率、室壁运动幅度和室壁运动速度反而又减低 ;而对照组给予多巴酚丁胺 5 μg/(kg·min)和 10 μg/(kg·min)后 ,室壁收缩增厚率、室壁运动幅度和室壁运动速度进行性减低。 结论　KTP激光TMLR后梗死局部部分心肌保持存活。     

KTP激光心肌打孔联合血管内皮生长因子转染对犬心功能的影响

目的探讨在KTP激光心肌打孔(TMLR)基础上联合血管内皮生长因子(VEGF)基因转染治疗对急性心肌梗死犬心功能的影响。方法家犬18只,随机均分为单纯心肌梗死组(SMI组)、TMLR组和TMLR+转VEGF基因组(TMLR+VEGF组)。结扎左前降支中段造成急性心肌梗死,TMLR组在梗死区以KTP激光行TMLR,TMLR+VEGF组在TMLR后于孔道边缘心肌内注射PAdTrack/VEGF165裸质粒2mg。术后8周,应用M型、二维及多普勒组织成像(DTl)技术检测左室局部和整体功能。结果①反映左心室整体收缩功能的指标,在SMI组、TMLR组和TMLR+VEGF组依次增大(P<0·05),并且TMLR+VEGF组分别与SMI组、TMLR组比较,差异均有显著性(P<0·05);②反映左室局部功能的主要指标,在以上三组依次增大(P<0·05);③反映心脏舒张功能的指标,在以上三组依次增大,但三组之间无统计学差异意义(P>0·05)。结论KTP激光心肌打孔联合VEGF165基因治疗,能增强KTP激光心肌打孔血运重建的疗效,进一步改善梗死心肌局部功能和整体收缩功能,但对整体舒张功能无明显影响。     

心肌梗死单个核细胞移植心肌运动的组织多普勒观察

目的：观察新生犬外周血单个核细胞心肌内移植对急性心肌梗死左室心肌运动的影响。方法：新生犬外周血单个核细胞经分离纯化后直接注射进入成年犬前壁心梗区域，对照组注射无血清培养基，分别应用组织多普勒技术（2．5MHz）分别检查术前，术后2d，术后30d心脏左室各部位心运动速度的变化。常规超声心动图检测射血分数，心输出量的变化。结果：术后2d两组均出现左室缺血区心肌运动速度下降，前壁增厚度率下降，左室其余各壁（室间隔除外）代偿性运动增强，二尖瓣侧壁运动显示左室收缩舒张功能降低无明显差别，心输出量，射血分数降低，术后30d，细胞移植组左室收缩舒张功能得以较好保持，左室运动改善，两组相比差别显著。结论：单个核细胞移植可以有效改善心肌梗死后左室心肌运动，有效维持心脏收缩及舒张功能。     

急性心肌梗死后左室重构的动态观察

目的：观察急性心肌梗死前后心肌结构的变化，探讨心梗后左室重构变化规律。方法：16只成年健康犬麻醉后开胸结扎前降支建立心梗模型，经胸超声心动图（2．5HMz）分别于术前、术后2d、术后30d观察心脏形态，心功能及心肌应力变化。结果：术后2d出现左室扩张，收缩和舒张功能减低，心肌应力增高，左房射血力增加。术后30d较术后早期，左室进一步扩张，收缩舒张功能持续降低，心肌应力术后早期高。结论：心肌梗死后早期即出现心室扩张，收缩和舒张功能降低，心肌应力增加，心梗死左室重构贯穿整个疾病过程。     

直接注射移植自体骨骼肌成肌细胞对成年犬急性心肌梗死后心脏功能的影响

目的：观察急性心肌梗死区心肌内直接注射移植自体骨骼肌成肌细胞对心肌梗死犬左室功能及心室重构的影响。方法：①实验于2002-03／2003—09在中国医学科学院心血管病研究所（阜外心血管病医院）分子医学中心完成。选用杂种成年犬16只。②以机械法结合IA型胶原酶与胰蛋白酶的二步酶消化法的改良成年犬骨骼肌成肌细胞培养方法进行细胞原代培养及扩增。③结扎冠状动脉前降支中段，建立急性心肌梗死模型后，将动物随机分为2组：对照组和成肌细胞注射组，每组8只。对照组：在梗死区点状注射生理盐水；成肌细胞注射组：在梗死区点状注射成肌细胞悬浮液。④冠状动脉结扎前、结扎后15min及4周时以漂浮导管测定左室功能指标（左室压力最大上升和下降速率，心排出量），将左室压力最大上升和下降速率与左心室收缩末压相除获得其校正值，结扎后4周行超声心动图检查（包括左室舒张末容积、左室收缩末容积、每搏输出量及左室射血分数），计算室壁节段运动指数和体现左室重构的球形指数。⑤组间比较分析用t检验，组内不同时段数据分析用配对t检验。结果：成肌细胞注射组的2只动物分别死于心肌梗死模型建立过程中的室颤和术后猝死，对照组的死亡动物中2只死于术后猝死，1只死于术后严重感染，进入结果分析11只犬（成肌细胞注射组6只，对照组5只）。①左室功能参数的变化：对照组冠状动脉结扎后即刻左室压力最大上升和下降速率、左室压力最大上升和下降速率／左心室收缩末压和心排出量明显低于结扎前，且术后4周时心排出量仍明显低于结扎前（P〈0．05）；成肌细胞注射组术后4周各指标基本恢复至冠状动脉结扎前水平（P〉0．05）；其收缩功能指标明显高于对照组（P〈0．01），也比冠状动脉结扎后显著上升（P〈0．05），而左室压力最大下降速率和左室压力最大下降速率／左心室收缩末压基本无变化（P〉0．05）。②超声心动图检测左室重构及心功能结果：成肌细胞注射组结扎后4周左室射血分数明显高于对照组（P〈0．05），余指标无显著变化（P〉0．05）。结论：心肌内直接注射移植自体骨骼肌成肌细胞能显著提高犬急性心肌梗死后左室收缩功能，不能改善急性心肌梗死后左室舒张功能和左室重构指标。     

高血压病早期左心结构及舒张功能的彩色多普勒超声心动 图观测

目的 探讨高血压病早期左心结构及舒张功能的改变。方法 应用二维彩色多普勒超声心动图,检测年龄≤45岁的Ⅰ级高血压患者左房内径、左室内径、室壁厚度、左室心肌重量、收缩及舒张功能。结果 Ⅰ级高血压组左房增大发生率为83％（39／47）,左房内径与对照组比较有显著性差异（P＜0.01）。舒张功能指标E／A与对照组比较亦有差异（P＜0.05）。结论 左房增大及左室舒张功能减低为早期高血压病的最早心脏改变,发生在左室肥厚及扩大之前。     

急性心肌缺血激光打孔与碱性成纤维生长因子联合应用后心脏功能变化的实验研究

目的：运用超声技术评价急性心肌缺血激光打孔与碱性成纤维生长因子缓释联合应用后心脏局部和整体功能的变化。方法：18条健康杂种犬随机分成三组：即急性心肌缺血组（AMI组），激光打孔组（TMLR组）和激光打孔联合碱性成纤维生长因子组（bFGF-FG组），所有实验犬均结扎左前降支中段造成急性心肌缺血模型，TMLR组和bFGF-FG组在冠状结扎后30分钟于缺血区心肌用KTP激光打孔（TMLR），bFGF-FG组并于打孔的心肌隧道内埋植碱性纤维生长因子缓释栓（bFGF-FG）。术后2个月用二维，M型及多普勒组织成像（DTI）等超声左室乳头肌水平前壁及前间壁厚度（TLVAW，TAIVS）增厚度（△T%）及前壁运动幅度（MA），左室短轴缩短率（FS），面积缩小分数（FAC），射血分数（EF），每搏量（SV）和心输出量（CO），在AMI，TMLR和bFGF-FG三组依次增大，其中TMLR组MA和EF与AMI组之间的差异有显著性意义（P＜0．05或P＜0．01），bFGF-FG组TVAW，△T%，MA，FAC，EF，SV和CO和AMI组之间以及TLVAW，MA，SV和EF与TMLR组之间的差异亦有显著性意义（P＜0．05或P＜0．01），余参数各组之间无明显差异（P＞0．05），室壁运动记分指数（WMSI）在AMI，TMLR和bFGF-FG三组依次降低，且三组裼 差异均有显著性意义（P＜0．05或P＜0．01）。左室前壁心肌和二尖瓣瓣环DTI参数s及e/a在AMI，TMLR和bFGF-FG三组亦依次半大，其中TMLR组左室前壁e/a与AMI组之间，bFGF-FG组左室前壁s和e/a与AMI组之间以及左室前壁e/a与TMRL组之间的差异均有显著性意义（P＜0．05或P＜0．01），余参数各组之间无明显差异（P＞0．05）。结论：激光打孔心肌内埋植碱性成纤维生长因子缓释，能够阻止急性心肌缺血心脏局部及整体功能的进一步损害，是TMLR方法学上的一个拓展。     

声学定量技术对高血压患者左室功能的评价

目的：应用声学定量（AQ）技术评价高血压患者的左室收缩和舒张功能。方法：48例高血压患者和20例正常对照进行了AQ检测，根据左室心肌重量指数（LVMI），高血压组又分为高血压LVMI正常组与左室肥厚组。结果：与对照组左室舒张功能指标比较，高血压患者左室充盈异常，舒张早期充盈减低，舒张晚期充盈增强；与高血压LVMI正常组比较，高血压左室肥厚组左室充盈尤其是舒张早期充盈低于高血压LVMI正常组；与对照组左室收缩功能指标比较，高血压LVMI正常组左室收缩功能正常，且处于高血流动力学状态，而高血压左室肥厚组左室收缩功能减低，且低于LVMI正常组；与对照组左室容量指标比较，高血压LVMI正常组左室容量负荷增大，而高血压左室肥厚组无显著差异。结论：AQ技术为定量评价高血压患者的左室收缩和舒张功能提供了新的途径。     

彩色超声心动图评价心肌梗死恢复期经皮冠状动脉介入治疗对左心室重构及收缩功能改变的研究

目的彩色超声心动图评价心肌梗死恢复期经皮冠状动脉介入治疗对左心室重构和收缩功能的影响。方法将择期行经皮冠状动脉介入治疗成功的70例冠心病患者按有无急性心肌梗死分为2组,心肌梗死组48例（前壁梗死者38例,下壁梗死者8例,其他部位梗死2例）,非心肌梗死组22例。采用彩色超声心动图检测2组患者左心室各项左心室重构和功能值：左室舒张末容积（LVEDV）、左室舒张末容积指数（LVESVI）、收缩末容积（LVESV）、每搏量（SV）、每搏量指数（SVI）、左室射血分数（LVEF）及左室收缩末压（LVESP）,观察其变...     

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.