构建毛果芸香碱急性致痫小鼠模型

目的:建立毛果芸香碱诱导的小鼠急性癫痫模型,并探讨其特点。方法:实验于2001-10/2002-10在上海复旦大学华山医院神经病学实验室完成。取健康雄性C57BL/6小鼠199只,随机分为生理盐水组(n=66)和致痫组(n=133)。所有小鼠皮下注射硝酸东莨菪碱1mg/kg,30min后致痫组腹腔注射毛果芸香碱350mg/kg(10g/L),生理盐水组腹腔注射生理盐水35μL/g。注射后连续6h观察小鼠是否有痫性发作并分级(0级,无抽搐;Ⅰ级,耳、面部抽搐;Ⅱ级,肌阵挛,但无直立位;Ⅲ级,肌阵挛,伴直立位;Ⅳ级,全身强直阵挛发作;Ⅴ级,强直阵挛发作,并失去体位控制),当小鼠持续痫性发作达1h时给予地西泮4mg/kg腹腔注射,如不能缓解痫性发作,可重复给予地西泮一两次,直到痫性发作被解除。对照组6只和致痫组30只同时描记脑电图。结果:199只小鼠全部进入结果分析。①痫性发作情况:生理盐水组小鼠均无痫性发作;致痫组全部出现痫性发作,其中Ⅰ级15只,Ⅱ级7只,Ⅲ级9只,Ⅳ级21只,Ⅴ级81只,呈Ⅲ～Ⅴ级持续发作(即癫痫持续状态)97只,死亡31只。癫痫持续状态模型成功率为50%。②脑电图结果:Ⅱ级以上发作的小鼠均可见到爆发性高波幅慢波、棘波或棘慢波。结论:毛果芸香碱致痫小鼠急性模型同相应的大鼠模型一样,具有制作简便、痫性发作潜伏期短、致痫率高等特点,其所产生的慢性癫痫模型具有与人类颞叶癫痫相似的行为、脑电与神经病理改变。     

乳铁蛋白对SNL神经病理性疼痛大鼠的镇痛作用

目的:研究乳铁蛋白对神经病理性疼痛大鼠的镇痛作用。方法:SD大鼠40只,随机分为5组(n=8)。结扎L5、L6脊神经(SNL)模型制成后第5天,分别腹腔注射生理盐水1ml(组Ⅰ)或乳铁蛋白0.5g/kg(组Ⅱ)、1g/kg(组Ⅲ)、2g/kg(组Ⅳ)溶于生理盐水1ml腹腔注射,腹腔内注射乳铁蛋白1g/kg 纳洛酮2mg/kg(组Ⅴ)。观察给药前和给药后不同时间点各组大鼠机械性痛敏实验的压力阈值(PPT)和热敏实验的潜伏期(PWL)。结果:与组Ⅰ比较,组ⅡPPT和PWL差异无统计学意义;组Ⅲ、Ⅳ给药后30～180min PPT升高,30～60min PWL延长。组Ⅴ与组Ⅰ比较,PPT和PWL差异无统计学意义,与组Ⅴ相比,组Ⅲ、组Ⅳ给药后30～180min PPT增加,30～60min PWL延长。结论:乳铁蛋白通过阿片受体介导,对神经病理性疼痛大鼠产生镇痛作用。     

双异丙酚预处理对内毒素诱导的人中性粒细胞释放白细胞介素-8和肿瘤坏死因子-α及相应mRNA表达的影响

目的 探讨双异丙酚预处理对内毒素(LPS)诱导的健康成年人静脉血中性粒细胞(polymorphonuclear leukocyte,PMN)释放白细胞介素(interleukin,IL)-8和肿瘤坏死因子(tumor necrosis factor,TNF)-α的影响及其应mRNA表达的变化.方法 采集健康成人志愿者静脉血分离提纯PMN,用1640培养液制成悬液;试验分为6组:Ⅰ组(空白对照组,PMN+培养液),Ⅱ组(双异丙酚溶剂对照组,intralipid),Ⅲ组(双异丙酚组,终浓度5 mg/L双异丙酚),Ⅳ组(内毒素组,终浓度1 mg/L LPS),Ⅴ组(内毒素+溶剂对照组,intralipid+终浓度1 mg/L LPS),Ⅵ组(双异丙酚+内毒素组,终浓度5 mg/L双异丙酚+终浓度1 mg/L LPS).加药培养12h后,ELISA法检测培养上清液TNF-α、IL-8的浓度,荧光定量PCR检测PMN IL-8 mRNA、TNF-αmRNA表达量.结果 与Ⅰ组比较,Ⅳ组、Ⅴ组、Ⅵ组IL-8浓度升高,Ⅳ组TNF-α浓度升高(P<0.05);与Ⅳ组比较,Ⅵ组IL-8和TNF-α浓度降低(P<0.05).与Ⅰ组比较,Ⅳ组、Ⅴ组、Ⅵ组IL-8mRNA表达上调,Ⅳ组TNF-α mRNA表达上调(P<0.05);与Ⅳ组比较,Ⅵ组IL-8 mRNA和TNF-α mRNA表达下调(P<0.05).结论 双异丙酚预处理可通过抑制内毒素诱导的人PMN释放IL-8、TNF-α,下调JL-8、TNF-α的mRNA表达,对PMN介导的炎症反应具有抑制作用.     

葛根素通过抑制TLR4信号通路改善LPS诱导的认知障碍

目的:研究葛根素对LPS诱导的脓毒症小鼠认知功能的影响.方法:将30只C57BL/6小鼠随机分为3组(每组10只):对照组(control组)、造模组(LPS+Vehicle组)、治疗组(LPS+Puerarin组).对照组小鼠腹腔注射等体积的生理盐水;造模组小鼠腹腔注射LPS 5 mg/kg;治疗组小鼠腹腔注射LPS...     

腹腔复苏对失血性休克大鼠小肠黏膜的保护作用

目的 探讨腹腔复苏对失血性休克大鼠小肠黏膜的保护作用.方法 健康雄性SD大鼠50只随机(随机数字法)分成5组:假手术组(Ⅰ组)、失血性休克组(Ⅱ组)、静脉复苏组(Ⅲ组)、静脉复苏加生理盐水腹腔复苏组(Ⅳ组)、静脉复苏加PD-2液腹腔复苏组(Ⅴ组).Ⅰ组依次行右颈总动脉、右股静脉、左股动脉插管及全身肝索化;Ⅱ组在Ⅰ组基础上经左股动脉放血制备失血性休克大鼠模型;Ⅲ组在造模后经右股静脉补入放出的血量及2倍量林格氏液进行复苏;Ⅳ组和Ⅴ组分别在Ⅲ组基础上经腹腔内注入生理盐水、2.5%PD-2液各30 mL.各组分别于造模及复苏后60～120 min取材.测定血浆二胺氧化酶(DAO)活性、D-乳酸(D-LA)含量及内毒素(LPS)含量,光镜和电镜下观察大鼠小肠黏膜组织学和超微结构变化.采用单因素方差分析对数据进行统计学处理.结果 Ⅱ组血浆DAO活性、D-LA及LPS含量均较Ⅰ组明显升高,差异具有统计学意义(P<0.01);Ⅴ组分别与Ⅱ、Ⅲ及Ⅳ组比较,血浆DAO活性、D-LA及LPS含量差异有统计学意义(P<0.05 or P<0.01).各组小肠黏膜组织病理学及黏膜超微结构比较,Ⅱ组较Ⅰ组有明显损伤,Ⅴ组较Ⅱ、Ⅲ及Ⅳ组损伤明显减轻.结论 PD-2液腹腔复苏可减轻失血性休克大鼠小肠黏膜组织病理学损害,保护肠黏膜完整性,降低肠壁通透性,防止内毒素血症发生.     

内毒素预处理对内毒素血症大鼠肝损伤的保护作用

目的 探讨内毒素预处理对内毒素血症大鼠肝损伤的保护作用.方法 采用直接注射内毒素的方法建市大鼠急性内毒素血症模型.雄性Wistar人鼠72只,随机分成三组:生理盐水对照组(N组,n=24只)、内素脂多糖(IPS)(L组,n=24只)和LPS预处理组(P组,n=24只),每组义按时间分为2 h组、4 h组、6 h组、12 h组4个亚组,每个亚组6只.P组:首次经腹腔注射LPS 0.25mg/kg;24 h后再经腹腔注射IPSO.5 mg/kg,其余两组给予等容量生理盐水.第二次腹腔注射72 h后,L组和P组经尾静脉一次注射LPS 10 mg/kg,N组给予等量生理盐水,L组和P组在注射LPS后2,4,6,12 h,N组在注射最后一次NS后2,4,6,12 h,各取6只取肝组织制成匀浆检测Toll样受体4(Toll likereceptor-4,TLR-4)、核因子-кB(nuclear factor kappa B,NF-кB)、肿瘤坏死因子-α(tulnor necrosis factor-a,TNF-α)和丙二醛(malondiahtehyde,MDA),抽血检测谷丙转氨酶(ALT),谷草转氨酶(ASF),取肝脏(肝左上叶)用10%的中性甲醛固定.采用SPSS 13.0统汁软件进行单因素方差分析.结果 内毒素血症时符时间点肝脏组织TLR-4,NF-кB和TNF-α浓度较对照组显著升高,而内毒素预处理后则有明显下降,其中内毒素血症时4 h组肝脏组织TLR-4,NF-кB和TNF-α分别为(38.76±0.67),(170.82±31.40),(293.16±49.49)和(6.263±0.351),显著高于对照组(P＜0.05),而内毒素预处理后上述指标降至(22.32±1.35),(135.55±26.44)和(234.23±44.96),差异有统计学意义(P＜0.05).结论 内毒素预处理可减轻内毒素血症时的肝损伤,其机理可能与肝组织TLR-4,NF-кB和TNF-α的表达减少有关.     

新生小鼠全身炎症反应综合征时肺组织糖皮质激素受体的表达及意义

目的 检测小鼠全身炎症反应综合征(SIRS)时肺组织糖皮质激素受体(GR)的表达,探讨GR在内毒素引起SIRS过程中的作用.方法 40只新生小鼠随机分为4组,每组10只:实验组A、B、C及对照组D.实验组以尾静脉注射脂多糖(LPS)法建立SIRS模型,其中实验组A予麻醉后尾静脉注射LPS(5 mg/kg);实验组B、C均先予LPS预处理:实验组B予腹腔注射LPS(0.25 mg/kg),24 h后处理同实验组A;实验组C予腹腔注射LPS(0.25 mg/kg),24 h后再次腹腔注射LPS(0.5 mg/kg),第2次注射24 h后处理同实验组A;对照组D仅予以麻醉.各组末次注射24 h后采集肺脏标本,行HE染色肺组织病理评分,免疫组化检测GR蛋白、逆转录聚合酶链反应法(RT-PCR)检测GR mRNA的表达.结果 (1)小鼠肺组织病理评分实验组A(6.44±1.16)、B(4.12±1.07)和C组(4.10±1.31)均高于对照组D(2.52±0.93,P均＜0.05);LPS预处理组B、C的肺组织病理评分明显低于实验组A(P均＜0.05).(2)对照组D小鼠肺组织GR蛋白及GR mRNA的表达水平高于实验组A,低于预处理组B和C,差异有统计学意义(P均＜0.01).结论 新生小鼠SIRS时肺组织GR表达减少,其与SIRS的发展、转归相关;LPS重复刺激可使新生小鼠产生耐受性,耐受性的产生与GR的表达调高相关.     

哌替啶类衍生物造模帕金森病小鼠的最佳剂量

目的:比较不同剂量哌替啶类衍生物1-甲基-4-苯基-1,2,3,6-四氢吡啶(1-methy-4-phenyl-1,2,3,6-tetrahydropyrindine,MPTP)建立的帕金森病小鼠模型对小鼠纹状体多巴胺含量的影响。方法:实验于2003-11/2004-07在北京宣武医院神经生物学实验室完成。选择C57BL/6L小鼠60只,采用不同剂量MPTP建立帕金森病小鼠模型,随机分6组,MPTP40mg/kg皮下注射1次组10只;MPTP20mg/kg腹腔注射,每2h1次,注射3次组10只;MPTP25mg/kg腹腔注射,每2h1次,注射3次组10只;MPTP45mg/kg皮下注射1次组10只;MPTP35mg/kg皮下注射1次组10只;正常对照组10只。采用Lowry法测定纹状体组织中多巴胺含量/蛋白质含量。结果:纳入动物60只,52只进入结果分析,其中8只均在处死前死亡。MPTP使小鼠纹状体多巴胺含量显著性下降。正常对照组多巴胺含量为(136.39±41.61)μg/g;MPTP35,40,45mg/kg皮下注射1次组分别为(107.97±26.92),(85.91±24.60),(74.13±12.49)μg/g,分别是正常对照组的79.16%,62.99%,54.35%;MPTP20,25mg/kg腹腔注射每2h1次,注射3次组分别为(44.90±18.41),(44.30±29.44)μg/g,分别是正常对照组的32.92%,32.48%。5个模型组与正常对照组比较差异均显著(P<0.01)。结论:MPTP20mg/kg腹腔注射每2h1次,注射3次和MPTP40mg/kg皮下注射1次两种模型是对帕金森病不同研究方向的理想模型。     

α黑素细胞刺激素及其类似物对内毒素休克小鼠的保护作用

目的 研究α黑素细胞刺激素（α－NSH）及其类似物（NDP－MSH）对内毒素休克小鼠的保护作用。方法 腹腔注射LPS50ug/kg和D－半乳糖（D－Gal)900mg/kg复制小鼠内毒素休克模型,研究不同剂量α-MSH及NDP－MSH在不同时间或经不同途径给药给药对内毒素休克小鼠生存率的影响。用常规病理切片观察α-MSH对内毒素休克小鼠重要脏器病理变化的影响。结果 未给予α－MSH的内毒素休克小鼠在9h内全部死亡,经尾静脉、腹腔和皮下注射α-MSH2.5mg/kg或5.0mg/kg均可以起到一定的保护作用;给予LPS前后不同时间注射2.5mg/kgα-MSH都可以明显延长内毒素休克小鼠起始死亡的时间,提高存活率,其中以给予LPS后1h经腹腔给药疗效最好,72h的生存率达33.3%,但增加给药次 未见疗效提高。经腹腔注射2.5mg/kgNDP－MSH,小鼠平均起死亡时间较α-MSH组延长4h,72h的生存率升至44.4%。病理学检查结果表明α-MSH可以减轻LPS引起的肝脏、脾脏及肺脏瘀血及细胞坏死。结论 α-MSH及NDP－MSH可以减轻LPS引起的小鼠重要脏器的病理损害,对内毒素休克小鼠有明显的保护作用。     

内毒素耐受大鼠肺部iNOS和NO表达的动态变化和意义

目的 研究内毒素血症时内毒素耐受大鼠肺部诱导型一氧化氮合酶(iNOS)、一氧化氮(NO)的动态变化.方法 72只SD大鼠随机分为对照组(NC组)和内毒素耐受组(ET组).腹腔注射小剂量内毒素(LPS),第1天0.1 mg/只;第2～5天0.5 mg/只,建立内毒素耐受模型.NC组腹腔注射同等剂量生理盐水.最后一次注射LPS 72 h后,两组均腹腔注射大剂量LPS(10 mg/kg).各组按注射LPS前(0 h),注射后2、4、6、12、24 h分为六小组(n=6).通过比色法(即Griess法)测量肺组织iNOS、NO、丙二醛(MDA)及髓过氧化物酶(MPO)含量.同时在第6、12 h取大鼠左下肺组织行组织病理形态学观察.用SPSS13.0统计软件进行统计分析.结果 NC组大鼠在大剂量LPS刺激后肺组织iNOS和NO在4 h开始升高,6～12 h达到高峰(P＜0.05);MDA和MPO含量在2 h即开始升高,4～12 h达到高峰(P＜0.05).ET组大鼠在大剂量LPS刺激前肺组织iNOS、NO、MDA和MPO即有微量升高(P＞0.05),大剂量LPS刺激后肺组织iNOS、NO、MDA和MPO亦有升高,但与NC组相比明显降低(P＜0.05).病理学检查显示,ET组肺组织损伤明显较NC组减轻.结论 内毒素耐受时,大剂量内毒素血症引起的大鼠肺部损伤减轻与肺部iNOS、NO低表达有关.     

Guns and Knives in New Mexico: Patterns of Penetrating Trauma, 1978–1993

Objective: To identify patterns of nonfatal and fatal penetrating trauma among children and adults in New Mexico using ED and medical examiner data.
Methods: The authors retrospectively sampled in 5-year intervals all victims of penetrating trauma who presented to either the state Level-1 trauma center or the state medical examiner from a 16-year period (1978–1993). Rates of nonfatal and fatal firearm and stabbing injury were compared for children and adults.
Results: Rates of nonfatal injury were similar (firearm, 34.3 per 100,000 person-years; stabbing, 35.1). However, rates of fatal injury were significantly different (firearm, 21.9; stabbing, 2.7; relative risk: 8.2; 95% confidence interval: 5.4, 12.5). From 1978 to 1993, nonfatal injury rates increased for children (p = 0.0043) and adults (p < 0.0001), while fatal penetrating injury remained constant. The increase in nonfatal injury in children resulted from increased firearm injury rates. In adults, both stabbing and firearm nonfatal injury rates increased.
Conclusions: Nonfatal injury data suggest that nonfatal violence has increased; fatal injury data suggest that violent death rates have remained constant. Injury patterns vary by age, mechanism of trauma, and data source. These results suggest that ED and medical examiner data differ and that both are needed to guide injury prevention programs.     

Systematic Reviews Published in the January 2011 Issue of The Cochrane Library

ABSTRACT

The Cochrane Library of Systematic Reviews is published quarterly as a DVD and monthly online. The January 2011 issue (first quarterly DVD for 2011) contains 4515 complete reviews, 1985 protocols for reviews in production, and 13,521 one-page summaries of systematic reviews published in the general medical literature. In addition, there are citations of 641,000 randomized controlled trials, and 14,018 cited papers in the Cochrane methodology register. The health technology assessment database contains over 9300 citations. One hundred and seven new reviews have been published in the last 3 months, of which five have potential relevance for practitioners in pain and palliative medicine.     

Interprofessional approaches to creating safe,high quality health care

Three supplementary perspectives are presented arguing that interprofessional collaboration is both necessary and desirable. Nonetheless, there are often too many serious intra-professional barriers and obstacles to interprofessional collaboration to make it successful. Some of these barriers, it is argued and illustrated, are found in the multiple ways in which professional identity is tacitly acquired and embodied in the practitioners' habitual, everyday practice. The paper then explores ways in which reflection, especially Second order reflection, can help to elucidate and overcome these obstacles, as well as increasing professional adaptability and competence.     

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.     

Prise en charge des entorses externes de cheville : étude clinique préliminaire sur l’efficacité du dispositif Myolux™

Ankle sprains are the most common injury of the musculoskeletal system and are associated with significant societal and economic impacts. It has been proven that classical therapeutic strategies may not be effective in preventing recurrent injuries: the recurrence rates reported in the literature can reach 73%. In order to provide an effective rehabilitation solution, a destabilizing orthosis was developed. This device is equipped with a mechanical articulator reproducing the subtalar mechanics and placed under the heel. In this paper, we present the main results of a preliminary clinical study conducted between 2004 and 2007. All subjects included in this study were treated with the abovementioned orthosis during 10 rehabilitation sessions of 30 minutes each. Data show a relatively low recurrence rate of 12% for the overall population. Moreover, it's of primary importance to note that this satisfactory ratio is largely reduced (3% of recurrence rate) for the 29 patients who performed one training session per month after the 10th initial rehabilitation sessions. Hence, the destabilizing orthosis appears to be an effective solution to prevent recurrent ankle sprains. However, joint protection requires long-term and regular training sessions. This result has motivated the development of a similar device allowing patients to perform training sessions at home. Finally, data obtained in this study are promising awaiting the final results of the comparative, multicentric and independent clinical trials currently managed by the Hospices Civils de Lyon.     

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.