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1.
目的:本研究观察长期小强度跑台运动对C57BL/6J小鼠突触可塑性的影响,探讨运动提高学习和记忆能力的细胞机制。方法:3月龄雌性C57BL/6J小鼠随机分为运动组(12只)和对照组(12只)。运动组小鼠进行5个月小强度跑台训练,运动训练结束后进行Morris水迷宫检测学习和记忆行为学改变,1周后采用电生理学方法在体记录海马齿状回(DG)的群体峰电位(PS)和场兴奋性突触后电位(f-EPSP)的变化。电生理学测试后制备小鼠脑石蜡切片,采用免疫组织化学方法检测海马DG区突触素(SYP)的蛋白表达情况,并取海马组织利用Western blot方法检测SYP的蛋白表达。结果:电生理学结果显示,高频刺激后运动组小鼠PS幅值和f-EPSP斜率百分数均高于对照组,差异具有显著性(P0.05);运动组小鼠海马组织突触素蛋白表达水平明显高于对照组,差异具有显著性(P0.05);运动组小鼠海马齿状回突触素阳性反应产物的整合光密度值明显高于对照组,差异具有显著性(P0.05)。结论:5个月小强度跑台运动可增强C57BL/6J小鼠的突触结构和功能可塑性。  相似文献   

2.
目的:考察抗精神病药氟哌啶醇、氯氮平、奥氮平对小鼠空间记忆影响。 方法:实验于2003-11/2004-07在沈阳药科大学药学院神经药理实验室完成。选择健康雄性昆明种小鼠240只。①在测定游泳能力的实验中,每40只小鼠随机分为3组:氯氮平组、奥氮平组、氟哌啶醇组。受试药氯氮平分为0.1mg/kg,0.3mg/kg,1mg/kg剂量组及空白对照组,每组10只;奥氮平和氟哌啶醇均分为0.01mg/kg,0.03mg/kg,0.1mg/kg剂量组及空白对照组。每只小鼠皮下给药50min后,放入游泳能力测定装置中,从起始一端入水,记录小鼠从入水到爬上对面终点平台的游泳时间。②在Morris水迷宫实验中,分组同小鼠游泳能力实验。小鼠每天给药后50min进行训练,连续给药5d。在训练过程中,每只小鼠每天连续训练4次,连续进行5d。训练时,分别从4个端点(每个点每天只能使用1次)将小鼠面向池壁放入水中。记录每只鼠分别从4个端点入水开始到找到水下平台所需时间(逃避到平台上的潜伏期),此为学习成绩。若小鼠在60s内未找到平台,实验者将其放在平台上,停留20s,潜伏期按60s计算。每次训练间隔20s。4次潜伏期的算术平均值作为这一时间段的成绩,参与最终结果统计。 结果:240只小鼠均进入结果分析。①在游泳能力测定实验中,与空白对照组比较,0.01~0.1mg/kg氟哌啶醇,0.1~1mg/kg氯氮平及0.01~0、1mg/kg奥氮平对小鼠游泳时间无明显影响,也未见对小鼠游泳姿态、爬上平台能力有明显影响。②在Morris水迷宫实验中,连续测定5d的结果表明,与空白对照组比较,氟哌啶醇0.1mg/kg在第5天明显延长小鼠找到平台的时间;氯氮平0.3mg/kg在第4天明显延长小鼠找到平台的时间;氯氮平1mg/kg在第1,3,4,5天明显延长小鼠找到平台的时间;奥氮平0.1mg/kg在第3,5天明显缩短小鼠找到平台的时间。 结论:氟哌啶醇和氯氮平在不同程度上对小鼠的空间记忆有损伤作用,而奥氮平对小鼠的空间记忆有改善作用。  相似文献   

3.
目的观察雌激素对去卵巢C57BL/6J小鼠股骨内OPG、RAN和ApoE的影响方法采用双侧卵巢切除术制备骨质疏松的动物模型,1w后雌激素替代组开始每周腹腔注射苯甲酸雌二醇(EB)2次,假手术对照组和模型组均注射同等量的橄榄油,至第6周末。6w后应用HE染色和原位杂交法观察各组小鼠股骨内OPG、RANKL、ApoE的变化。结果去卵巢组股骨内OPG、RANKL和ApoE表达与对照组相比明显下降,而补充雌激素后OPG、RANKL和ApoE的表达明显上升。结论说明雌激素可通过增加股骨中OPG、RANKL和ApoE的表达,抗骨质疏松。  相似文献   

4.
目的:探讨IFN-γ对造血干细胞移植后肺部GVHD的作用。方法:应用C57BL/6J和B6D2F1小鼠通过造血干细胞移植(HSCT)建立小鼠GVHD模型。根据移植的方式将小鼠分为3组:同基因HSCT组(C57BL/6J→C57BL/6J),异基因HSCT组(C57BL/6J→B6D2F1)及IFN-γ-/-异基因HSCT组(IFN-γ-/-C57BL/6J→B6D2F1)。移植后分析比较3组小鼠生存期、aGVHD临床评分及肺组织病理,检测肺泡灌洗液中总细胞数及小鼠IFN-γ水平。结果:同基因移植组小鼠第42天全部存活,无aGVHD临床症状。异基因移植组小鼠有aGVHD表现,24 d生存率大于50%,GVHD临床评分高于同基因移植组。在移植后第28天肺组织病理可见肺泡出血及淋巴细胞浸润。IFN-γ-/-异基因移植组小鼠出现致死性aGVHD表现,14 d内小鼠全部死亡,GVHD临床评分第1周就高达6.7±0.83,明显高于异基因移植组,小鼠肺组织发生严重的aGVHD病理改变,其支气管肺泡灌洗液中总细胞数在移植后第1周较其他两组明显增高,但其血清中IFN-γ含量明显低于异基因移植组及同基因移植组(P0.05)。结论:供者来源的IFN-γ对造血干细胞移植后肺组织起重要的免疫保护作用。  相似文献   

5.
目的探讨丰富环境干预对缺血性脑卒中小鼠空间学习记忆能力,以及海马区凋亡相关蛋白Bcl-2和Bax表达的影响。方法清洁级成年雄性C57BL/6小鼠42只,接受永久性左侧大脑中动脉栓塞术。术后3 d,将造模成功的小鼠32只随机分为标准饲养组(n=16)和丰富环境组(n=16)。另选8只小鼠为假手术组。假手术组和标准饲养组置于标准环境中饲养,丰富环境组置于丰富环境中饲养。21 d后,行Morris水迷宫测试,Western blotting和免疫荧光染色检测海马区Bcl-2和Bax蛋白水平。结果与标准饲养组相比,丰富环境组逃避潜伏期缩短(P<0.05),目标象限内停留时间、停留距离和穿过原有平台次数增加(P<0.05);Bcl-2水平升高(P<0.05),Bax水平降低(P<0.05)。结论丰富环境可以改善缺血性脑卒中小鼠空间学习和记忆功能,可能与抵制海马区细胞凋亡有关。  相似文献   

6.
彭岩  肖昭扬  于德钦  赵杰  张万琴 《中国临床康复》2006,10(18):101-103,i0002
目的:探讨红藻氨酸处理的C57BL/6J小鼠癫痫发作后癫痫发作敏感性能否形成及其机制。 方法:实验于2004-03/06在大连医科大学生理学教研室进行。选用C57BL6J小鼠36只,实验分为盐水对照组(n=8)和红藻氨酸处理组(n=24)。红藻氨酸处理组根据不同时间点又分为红藻氨酸处理后0.5h,2h,24h组。每组8只。盐水对照组为C57BL/6J小鼠颈部皮下注射0.2mL盐水,红藻氨酸处理组为C57BL/6J小鼠颈部皮下注射0.2mL惊厥剂量红藻氨酸(25mg/kg)诱导癫痫发作,分别在红藻氨酸处理后0.5,2,24h,用免疫组化技术检测海马内c-Jun免疫阳性神经元,作为神经元兴奋的形态功能指标来观察癫痫发作相关脑区的兴奋传递通路,同时检测海马门区γ-氨基丁酸免疫反应活性阳性神经元数目。红藻氨酸处理后7d。存活的C57BL/6J小鼠被给予皮下注射12.5mg/kg阈下剂量的红藻氨酸,以检测癫痫发作敏感性。 结果:实验纳入36只C57BL/6J小鼠,中途有4只脱落,最终有32只进入结果分析。①惊厥剂量红藻氨酸诱发C57BL/6J小鼠(n=24)在30min内出现癫痫持续状态,并伴有全身强直阵挛性惊厥。其中4只在30min内死亡。②d后阈下种量未引起癫痫发作,即癫痫发作敏感性未形成。③脑内免疫组化显示,海马各部位γ-氨基丁酸免疫反应阳性神经元在检测各时间点内均未见任何脱失现象;与盐水对照组比较,红藻氨酸组诱发急性癫痫发作,红藻氨酸处理后,在海马齿状回颗粒细胞c-Jun免疫反应最早增强(P〈0.05),CA3部位不增强,以CA1部位c-Jun免疫反应在24h显著性升高(P〈0.001)。④与盐水对照组相比,惊厥剂量的红藻氨酸处理后0.5h,2h,24h,海马门区γ-氨基丁酸免疫阳性神经元的数目及染色程度未见明显改变(P〉0.05)。 结论:C57BL/6J小鼠具有对红藻氨酸引起癫痫急性发作的敏感,可能与CA1接受内嗅皮层海马穿通通路的直接投射有关,同时C57BL/6J小鼠海马对红藻氨酸引起的γ-氨基丁酸能神经元损伤不敏感,海马门区γ-氨基丁酸免疫反应阳性神经元的结构功能完整性可能在防止癫痫敏感性形成方面起着关键的作用。  相似文献   

7.
目的:探讨慢性不可预知性温和应激(CMS)对小鼠空间学习和记忆功能的影响。方法:健康成年昆明小鼠30只,随机分为2组,对照组和模型组,各15只。通过10种应激因子制备CMS损伤小鼠。6周后应用Morris水迷宫实验方法,检测小鼠空间学习、记忆能力。结果:模型组寻找平台的逃逸潜伏期高于对照组(P<0.01),在靶标象限停留的时间和穿越靶标象限的次数均显著低于对照组(P<0.01)。结论:CMS可导致小鼠空间学习和记忆功能发生障碍。  相似文献   

8.
目的:观察蝎毒对C57BL/6帕金森病小鼠运动协调与空间学习记忆能力以及脑内前脑啡肽原表达的影响。 方法:实验于2004-03/06在大连医科大学生理学教研室进行。将96只C57BL/6小鼠随机分为模型组、模型给药组、单独给药组、盐水对照组,每组24只。模型组为连续8d皮下注射1-甲基-4-苯基-1,2,3,6-四氢吡啶(20mg/kg);模型给药和单独给药组给予蝎毒耐热蛋白连续8d,盐水对照组给等量生理盐水。测定爬杆、游泳实验评价运动协调能力。Morris水迷宫实验观察空间学习记忆能力。免疫细胞化学观察脑内多巴胺能神经元数目,反转录-聚合酶链反应测试脑内前脑啡肽mRNA改变。 结果:96只小鼠均进入结果分析。①模型组小鼠的爬竿时间较盐水对照组、单独给药组延长,因此测试分数降低,出现运动障碍。模型给药组与模型组相比运动协调性障碍明显减轻(P〈0.01)。模型组小鼠的游泳实验测试分数较盐水对照组降低,游泳能力降低,出现运动障碍。模型给药组与模型组相比运动障碍明显减轻(P〈0.01)。②模型组小鼠寻找隐匿平台潜伏期明显比盐水对照组延长,盐水对照组小鼠空间学习能力下降。治疗组与模型组相比寻找隐匿平台潜伏期明显变短(P〈0.01)。模型组小鼠于第5天在目标象限游泳时间占总时间百分比明显比盐水对照组降低,在对侧象限游泳时间占总时间百分比明显比盐水对照组增高(P〈0.01)。模型组小鼠空间记忆能力下降。模型给药组与模型组相比有明显的改善(P〈0.01)。③与盐水对照组相比,模型组小鼠黑质致密部的TH免疫反应阳性多巴胺能神经元明显脱失。模型给药组与模型组相比TH免疫反应阳性多巴胺能神经元数目明显增加(P〈0.01)。④与盐水对照组相比,模型组小鼠脑区前脑啡肽原mRNA表达明显增强(P〈0.05)。模型给药组与模型组相比前脑啡肽原mRNA表达明显降低(P〈0.05)。 结论:蝎毒保护中脑黑质致密部多巴胺能神经元并改善1-甲基-4-苯基-1,2,3,6-四氢吡啶引起的运动协调性降低和空间学习记忆障碍,其保护机制可能与降低异常的前脑啡肽原表达有关。  相似文献   

9.
目的 探讨FIZZ1在ApoE基因敲除鼠粥样斑块表达情况并探讨其可能的表达细胞.方法 C57BL/6J ApoE基因敲除鼠及C57BL/6J野生型小鼠各9只,分别喂食高脂饲料及普通饲料,24周后处死小鼠,自主动脉根部至腹主动脉离断整个血管,石蜡包埋后作连续切片,行HE染色及FIZZ1免疫组化.检测血管斑块内FIZZ1表达情况,体外模拟粥样斑块内Th2型细胞因子环境,检测斑块内FIZZ1表达是否与Th2型细胞因子刺激平滑肌细胞或巨噬细胞有关.结果 免疫组化可见FIZZ1在粥样硬化斑块内明显表达,Th2型细胞因子可以刺激巨噬细胞FIZZ1表达,但不能刺激平滑肌细胞FIZZ1表达.结论 正常血管壁内未见FIZZ1表达,ApoE基因敲除鼠粥样斑块表达FIZZ1,动脉粥样硬化斑块内Th2型细胞因子刺激巨噬细胞可能为FIZZ1表达机理之一.  相似文献   

10.
目的:探讨长期有氧运动对apoE缺陷小鼠(apoE0)动脉粥样硬化斑块面积的影响及纤溶激活系统变化在其中的作用。方法:apoE0鼠和C57BL/6J鼠各20只随机分为对照组和游泳组,120min/次,6次/周,12周后测定apoE0鼠动脉粥样硬化斑块面积及纤溶激活活性。结果:①有氧训练使apoE0鼠的动脉粥样硬化斑块面积减少了35%;②apoE0鼠的纤溶和凝血系统均处于一种较高的水平;③有氧训练使apoE0鼠和C57BL/6J鼠血浆组织纤溶酶原激活剂(tPA)活性和tPA/纤溶酶原激活抑制剂(PAI)比值均明显升高,但C57BL/6J鼠PAI活性降低,apoE0鼠PAI活性保持不变;④有氧训练使apoE0鼠的纤溶酶原水平较之训练前显著升高,但纤溶酶、凝血酶原和凝血酶均未发生明显改变。结论:apoE缺陷鼠有着明显的凝血功能亢进和纤溶活性增强,长期有氧训练可缩小动脉粥样硬化病变面积,其过程中有纤溶机制的参与。  相似文献   

11.
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.  相似文献   

12.
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.  相似文献   

13.
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.  相似文献   

14.
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.  相似文献   

15.
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.  相似文献   

16.
17.
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.  相似文献   

18.
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.  相似文献   

19.
Ranganath C  Heller AS  Wilding EL 《NeuroImage》2007,35(4):1663-1673
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.  相似文献   

20.
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.  相似文献   

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