心力衰竭犬心房结构重构与心房颤动关系的研究

目的观察右室快速起搏建立心力衰竭犬模型的效果,探讨心房结构重构在心力衰竭与心房颤动形成过程中的作用机制。方法13只犬随机分为起搏组(7只)和假手术组(6只),于左、右心房各缝植4对电极,起搏电极缝植在右室心尖,连接实验用VOO型起搏器,快速心室起搏(220次/min)6周,建立心力衰竭犬模型,分别于起搏前、起搏6周后,应用经食管超声心动图测量左房收缩末容积,采用双平面Simpson法测量左室舒张期末和收缩期末容积,得出射血分数和心输出量;应用漂浮导管法测定血流动力学指标,即右心房压、肺动脉平均压、肺毛细血管楔嵌压及左室舒张末压;最后用光镜和电镜观察心房肌的超微结构。结果①超声显示起搏6周后,起搏组与假手术组比较,左房收缩末容积显著增大[(23.2±4.1)cm3对(13.2±1.7)cm3,P<0.01],左室舒张末期容积显著增大[(56.2±11.3)cm3对(33.7±9.6)cm3,P<0.01],左室收缩末期容积显著增大[(38.4±8.4)cm3对(14.5±8.6)cm3,P<0.01],射血分数显著降低[(31.4±10.2)%对(56.8±4.5)%,P<0.01],心输出量显著降低[(1.2±0.5)L/min对(2.8±1.6)L/min,P<0.01]。②血流动力学显示起搏犬右心房压、肺动脉平均压、肺毛细血管楔嵌压及左室舒张末压显著增高(P<0.01)。③病理学显示起搏犬心房肌细胞变性、肌纤维溶解、线粒体肿胀以及间质胶原增生、水肿。结论右室快速起搏可成功建立心力衰竭的动物模型,心房结构重构是心力衰竭犬发生心房颤动的重要原因。     

应用经胸超声心动图评估快速左心耳起搏心房颤动模型心脏结构及功能的变化

目的:应用经胸超声心动图观察高频率左心耳起搏致猪慢性心房颤动模型心脏结构和功能的变化。方法:实验于2005-09/2006-08在南京医科大学第一附属医院江苏省实验动物中心完成。①12只苏钟种猪随机分为实验组及对照组各6只,所有动物均开胸,将起搏电极固定在左心耳根部,高频率脉冲发生器植入左侧胸部囊袋。实验组术后恢复1周后起搏器以500次/min的频率快速起搏左心耳8周;对照组始终不起搏。②术后心电图定期监测起搏、心房颤动的发生情况;于术前、起搏后1周、起搏后4,8周超声心动图观察实验动物左房内径、心室收缩及舒张末左房面积、左房和左室射血分数、左室舒张及收缩末内径、左心室短轴缩短率等变化。结果:①实验组5只完成了实验,术后2周复查心电图,1只动物发生房颤,起搏8周3只发生阵发性房颤,1只未发生房颤;对照组则未发生任何心律失常情况。②左心房相关指标:起搏后1周,实验组左房内径、收缩末期左心房面积和舒张末期左房容积均较起搏前增加[(2.70±0.12),(2.50±0.12)cm;(6.78±0.81),(6.21±0.93)cm2;(4.66±0.53),(3.78±0.57)mL;P均<0.05],左房射血分数较起搏前下降[(55.6±6.0)%,(63.8±4.0)%,P<0.01],至起搏4,8周,左房射血分数进一步降低,左房内径等指标则继续增大。③左心室相关指标:起搏后1周,实验组左室舒张、收缩末期内径较起搏前增加[(3.64±0.13),(3.46±0.15)cm;(2.48±0.08),(2.14±0.09)cm;P均<0.01],左心室短轴缩短率和左室射血分数较起搏前下降[(31.6±2.0)%,(37.8±3.0)%;(60.8±2.0)%,(69.2±4.0)%;P均<0.01];至起搏4,8周,左心室短轴缩短率和射血分数进一步降低,左室舒张、收缩末期内径则继续增大,与对照组比较也差异显著(P<0.05,0.001)。结论:①超声心动图是监测房颤模型建立过程中心房、心室结构和功能变化的有效手段。②高频起搏左心耳是建立猪心房颤动模型的有效方法,快速心房起搏可导致左心房左心室增大及心功能减退。     

超声三维斑点追踪评价不同心脏起搏方式对健康犬左心室功能的影响

目的 探讨超声三维斑点追踪成像技术评价不同心室位点心脏起搏对健康犬左室壁机械同步性和左室功能的影响.方法 分别采集10只健康开胸比格犬基础状态和右室心尖、左室心尖、左室侧壁起搏状态一个完整心动周期的左心室全容积实时图像;同步记录左室压力时间变化曲线并获取左室射血压力和收缩期压力最大上升速率.用超声三维斑点追踪分析软件分别提取不同状态左室壁径向三维应变图、左室壁径向三维峰值应变和左室收缩末期容积、舒张末期容积、射血分数、每搏输出量、心输出量.定性观察并比较不同状态左室壁各节段心肌的径向三维应变同步性.对定量参数进行配对t检验、卡方检验和直线相关分析.结果 ①左室心尖或侧壁起搏状态左室壁各节段心肌的径向三维应变不同步程度较右室心尖起搏状态明显.②左室心尖或侧壁起搏状态左室壁径向三维峰值应变显著减低的心肌节段数多于右室心尖起搏状态(9/16 对 2/16,P<0.05).③左室心尖或侧壁起搏状态左室壁整体径向三维峰值应变和左室每搏输出量、射血分数、心输出量均低于右室心尖起搏状态(P<0.05).④不同状态左室壁整体径向三维峰值应变分别与左室每搏输出量、射血分数、心输出量呈线性正相关(r=0.781～0.984,P<0.05).结论 左室心尖或侧壁起搏对健康犬左室壁机械同步性和左室功能的损害超过右心室心尖起搏.     

螺内酯对心衰患者左室重构的影响

目的:观察螺内酯对心衰患者左室重构的影响。方法:将100例心衰患者分为常规治疗组与螺内酯治疗组。结果:常规治疗组与螺内酯治疗组第12周进行超声心动图检查比较,螺内酯治疗组左室舒张末容积指数[(56.9±5.8)ml/m2]和收缩期末容积指数[(29.3±5.2)ml/m2]与常规治疗组[(64.8±6.2)ml/m2,(35.7±6.5)ml/m2]相比显著降低(P<0.01),二尖瓣血流舒张早期流速(VE)与心房收缩期流速(VA)比值(VE/VA)于常规治疗组相比显著增加(P<0.01),射血分数虽有增加,但变化差异无显著性(P>0.05)。结论:螺内酯可阻抑左室重构,改善左室功能。     

阿霉素诱导兔心肌病模型的建立及经胸超声心动图评价

目的　探讨阿霉素诱导兔心肌病模型的可行性并利用经胸超声心动图进行评估。方法　 2 0只兔每周静脉注射阿霉素 2 mg/ kg,共计 8周 (总剂量 16 mg/ kg) ,另 8只每周注射同等剂量的生理盐水作为对照组。基础状态 (未注药前 )、 12周时分别进行兔超声心动图检查 ,分别测量左室舒张期末、收缩期末内径 ,室间隔和左室后壁厚度 ,以及射血分数和短轴缩短率。 12周时阿霉素组和对照组分别取 2只进行心肌病理切片检查。结果　阿霉素组 ,与基础状态相比 ,12周时左室舒张期末内径显著扩大 [(10 .5± 1.3) vs (15 .8± 2 .1) mm ,P<0 .0 5 ],左室收缩期末内径显著扩大 [(8.7± 1.0 ) vs(10 .3± 1.1) m m,P<0 .0 5 ],射血分数显著降低 [(6 3.4± 8.4 ) vs(38.8± 7.6 ) ,P<0 .0 5 ],短轴缩短率显著降低 [(37.6± 7.6 ) vs (2 1.2± 6 .7) ,P<0 .0 5 ],室间隔和左室后壁厚度无显著性变化 (P>0 .0 5 ) ;对照组 ,左室舒张期末、收缩期末内径、室间隔和左室后壁厚度、射血分数和短周缩短率均无显著性变化 (P>0 .0 5 )。阿霉素组病理结果显示了与人类阿霉素心肌毒性相似的改变 ,心肌细胞变性、线粒体和肌浆网水肿、细胞内空泡增多以及凋亡细胞增多。结论　静脉注射阿霉素可以诱导形成非缺血性心肌病模型 ,结果可靠 ,成功     

右心室不同部位起搏时左心室总体及节段心肌收缩功能的超声评估

目的 应用斑点追踪显像技术评价右心室不同部位起搏对左心室总体及节段心肌收缩功能的影响.方法 获取右室间隔起搏组(9例)、右室心尖起搏组(15例)、正常对照组(13例)心尖左室长轴观、胸骨旁左室短轴观图像,测量各节段峰值纵向应变(S_L)、峰值径向应变(S_R),计算左室总体峰值纵向应变(GS_L)、总体峰值径向应变(GS_R).结果 右室心尖起搏组GS_L[-(18.29±2.67)%]低于正常对照组[-(21.07±2.08)%]及右室间隔起搏组[-(20.54±2.29)%],差异均具有统计学意义(P＜0.05),右室间隔起搏组与正常对照组GS_L比较差异无统计学意义(P＞0.05).而右室心尖起搏组GS_R[-(26.85±7.73)%]与右室间隔起搏组GS_R[(28.59±6.06)%]均低于正常对照组[(36.26±9.37)%],差异有统计学意义(P＜0.05),两起搏组间GS_R差异无统计学意义(P＞0.05),但右室心尖起搏组GS_R有进一步降低趋势.两起搏组邻近起搏位点的左室节段心肌S_L及S_R较正常对照组相应节段明显降低,但右室间隔起搏组保持了与正常对照组相似的左室内应变分布,右室心尖起搏组左室内应变分布异常.结论 斑点追踪显像技术可定量评价右室不同部位起搏时左室总体及节段心肌收缩功能变化.     

抗心房颤动起搏治疗阵发性心房颤动的临床疗效

目的评价抗心房颤动起搏治疗阵发性心房颤动(PAF)的临床疗效。方法入选泰安市中心医院2008年1月至2015年1月期间植入具有抗心房颤动功能的双腔起搏器的病态窦房结综合征伴PAF的208例患者,分为治疗组和对照组,每组104例。采用两组分阶段对照的方法,治疗组打开抗心房颤动起搏功能,对照组未打开抗心房颤动起搏功能,在术后6、12个月进行随访,观察起搏参数、心房颤动发作情况、临床表现、心功能、超声心动图、生活质量评分等并进行比较。结果随访6个月时,治疗组与对照组在心房颤动负荷[(33±8)%vs.(61±12)%],心房颤动发作次数[(21±5)次/月vs.(66±11)次/月],窦性心律持续时间占总时间的比例[(57±6)%vs.(41±6)%],自动模式转换(AMS)次数[(8±2)次/月vs.(13±3)次/月]比较,差异均具有统计学意义(均P<0.05)。随访12个月时,治疗组与对照组在心房颤动负荷[(20±9)%vs.(54±7)%],心房颤动发作次数[(19±5)次/月vs.(32±8)次/月],窦性心律持续时间[(71±5)%vs.(45±6)%],AMS次数[(6±1)次/月vs.(10±5)次/月],差异均具有统计学意义(均P<0.05)。随访12个月时治疗组SF-36量表总评分增加至(105.3±6.28)分,与对照组[(96.8±6.82)分]比较差异有统计学意义(P<0.05);彩色多普勒超声心动图指标中左心室射血分数有轻度改善,随访12个月时治疗组为(52.9±3.7)%,对照组为(49.4±4.2)%,心功能有所好转,其余各相关指标均无明显变化。结论抗心房颤动起搏治疗可显著减少患者PAF的发生,同时可改善患者的临床症状和生活质量。     

结缔组织生长因子在急性心肌梗死后心力衰竭大鼠心肌中表达与洛沙坦的调节

目的:观察结缔组织生长因子在急性心肌梗死后心力衰竭大鼠心肌中的表达特点和洛沙坦对其调节作用。方法:实验于2004-01/2005-03在华中科技大学同济医学院附属协和医院心血管病实验室完成。选择健康雌性SD大鼠60只,50只大鼠通过结扎大鼠左冠状动脉前降支制备急性心肌梗死后心力衰竭模型,术后6h存活的44只大鼠随机数字表法分为心力衰竭对照组24只,洛沙坦干预组20只。另设假手术组10只,相当于冠脉结扎部位穿线,但不结扎,然后立即缝合。洛沙坦干预组每天直接灌胃给予洛沙坦10mg/kg,2次/d;心力衰竭对照组及假手术组大鼠灌等量自来水,共计8周。治疗8周后行高频多普勒超声、血流动力学、心脏重塑指标、左室非梗死区心肌结缔组织生长因子蛋白免疫印迹测定。结果:纳入大鼠60只,去除死亡及梗死面积<35%和>55%的大鼠,最终进入结果分析32只。①大鼠左室结构和功能比较:多普勒超声检查提示,心力衰竭对照组的左室舒张末期内径、左室舒张末期容积、E峰、E峰减速度及E/A显著高于假手术组(P<0.01),左室短轴缩短率和射血分数显著低于假手术组(P<0.01)。洛沙坦干预组左室舒张末期内径、左室舒张末期容积、E峰、E峰减速度及E/A显著低于心力衰竭对照组[分别为(7.0±0.5),(8.7±0.6)mm;(421±26),(521±27)μL;(72±6),(95±7)cm/s;(26.5±2.6),(32.1±3.5)m/s2;4.9±0.5,10.3±0.8,P<0.01],左室短轴缩短率和射血分数显著高于心力衰竭对照组[分别为(26±4)%,(21±4)%;(39±4)%,(31±4)%,P<0.01]。②大鼠血流动力学和心室重塑指标改变:心力衰竭对照组平均动脉压明显低于假手术组(P<0.01),左室舒张末压、左心室心肌肥厚指数、右心室心肌肥厚指数和心肌胶原容积分数均显著高于假手术组(均为P<0.01)。洛沙坦干预组左室舒张末压、左心室心肌肥厚指数、右心室心肌肥厚指数和心肌胶原容积分数显著低于心力衰竭对照组[分别为(10.2±1.9),(20.1±2.5)mm Hg;2.30±0.11,2.45±0.12;0.69±0.07,0.92±0.11;(4.7±1.1)%,(8.2±1.2)%,P<0.01]。③大鼠左室心肌结缔组织生长因子蛋白表达的变化:心力衰竭对照组结缔组织生长因子蛋白表达高于假手术组(P<0.01)。洛沙坦干预组结缔组织生长因子蛋白表达低于心力衰竭对照组(分别为0.72±0.21,1.21±0.23,P<0.01)。结论:急性心肌梗死后心力衰竭大鼠左室非梗死区心肌结缔组织生长因子蛋白表达明显升高,洛沙坦对结缔组织生长因子蛋白表达的增加有抑制作用,并能明显减轻左室重塑和延缓心力衰竭进展。     

组织多普勒对慢性心力衰竭左心室内收缩同步性的研究

目的用组织多普勒(TDI)研究慢性充血性心力衰竭(心衰)患者左室内收缩同步性。方法对21例心衰患者和15例正常人,用标准超声测量左室射血分数(LVEF)、左室舒张末容积(LVEDV)和左室收缩末容积(LVESV),用TDI测量左室壁12个节段的收缩达峰时间(Ts),计算它们之间最大的差(Ts-maxD)和标准差(Ts-s)。结果心衰组的Ts-s和Ts-maxD[(49.4±22.0)ms和(158.9±72.8)ms]明显大于正常组[(29.1±8.7)ms和(91.8±21.4)ms,P<0.01]。Ts-s和Ts-maxD与LVEF有弱相关(r=-0.539和r=-0.566,P<0.05)。Ts-s与LVEDV和LVESV有中度相关性(r=0.603和r=0.622,P<0.01)。同样,Ts-maxD与LVEDV和LVESV也具有相关性(r=0.568和r=0.603,P<0.01)。结论心衰患者左室内存在收缩不同步现象,收缩不同步影响了心室的射血功能和心室的重塑。     

心房快速起搏对犬血管细胞黏附分子-1表达的影响

目的 研究心房快速起搏犬模型血管细胞黏附分子-1(vascular cell adhesion molecule-1,VCAM-1)的表达.方法 选用成年健康杂种犬13条,随机分为两组:快速起搏组7条,假手术组6条.两组均开胸于右心耳缝植AOO型起搏器,快速起搏组以400 bpm起搏6周,假手术组不起搏.应用酶联免疫法测定血清VCAM-1水平,采用逆转录-多聚酶链反应(RT-PCR)测定左房组织的VCAM-1 mRNA表达水平,同时进行左房的病理分析.结果 快速起搏组犬起搏6周后的血清VCAM-1水平明显高于假手术组(t=11.63,P<0.01),左房的VCAM-1 mRNA表达水平明显高于假手术组,增高32.1%(t=2.49,P=0.03);病理结果示快速起搏组犬左房心肌细胞变性.结论 心房快速起搏可引起犬血清VCAM-1及左房VCAM-1 mRNA表达水平增高.VCAM-1可能参与心房损伤时的心肌重构过程.     

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.     

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.     

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.     

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.     

Modified micro-superior percutaneously-assisted total hip: early experiences & case reports

Because of the extensile nature and familiarity of the standard posterior-lateral approach to the hip, a family of "micro-posterior" approaches has been developed. This family includes the Percutaneously-Assisted Total Hip (PATH) approach, the Supercapsular (SuperCap) approach and a newer hybrid approach, the Supercapsular Percutaneously-Assisted Total Hip (SuperPATH) approach. Such approaches should ideally provide a continuum for the surgeon: from a "micro" (external rotator sparing) posterior approach, to a "mini" (external rotator sacrificing) posterior approach, to a standard posterior approach. This could keep a surgeon within his comfort zone during the learning curve of the procedure, while leaving options for complicated reconstructions for the more practiced micro-posterior surgeons. This paper details one author's experiences utilizing this combined approach, as well as permutations of this entire micro-posterior family of approaches as applied to more complex hip reconstructions.     

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.     

Structure and function of "metalloantibiotics"

Although most antibiotics do not need metal ions for their biological activities, there are a number of antibiotics that require metal ions to function properly, such as bleomycin (BLM), streptonigrin (SN), and bacitracin. The coordinated metal ions in these antibiotics play an important role in maintaining proper structure and/or function of these antibiotics. Removal of the metal ions from these antibiotics can cause changes in structure and/or function of these antibiotics. Similar to the case of "metalloproteins," these antibiotics are dubbed "metalloantibiotics" which are the title subjects of this review. Metalloantibiotics can interact with several different kinds of biomolecules, including DNA, RNA, proteins, receptors, and lipids, rendering their unique and specific bioactivities. In addition to the microbial-originated metalloantibiotics, many metalloantibiotic derivatives and metal complexes of synthetic ligands also show antibacterial, antiviral, and anti-neoplastic activities which are also briefly discussed to provide a broad sense of the term "metalloantibiotics."