Functional Cross-Talk between the α1- and β1-Adrenergic Receptors Modulates the Rapidly Activating Delayed Rectifier Potassium Current in Guinea Pig Ventricular Myocytes

The rapidly activating delayed rectifier potassium current (I_Kr) plays a critical role in cardiac repolarization. Although I_Kr is known to be regulated by both α₁- and β₁-adrenergic receptors (ARs), the cross-talk and feedback mechanisms that dictate its response to α₁- and β₁-AR activation are not known. In the present study, I_Kr was recorded using the whole-cell patch-clamp technique. I_Kr amplitude was measured before and after the sequential application of selective adrenergic agonists targeting α₁- and β₁-ARs. Stimulation of either receptor alone (α₁-ARs using 1 μM phenylephrine (PE) or β₁-ARs using 10 μM xamoterol (Xamo)) reduced I_Kr by 0.22 ± 0.03 and 0.28 ± 0.01, respectively. The voltage-dependent activation curve of I_Kr shifted in the negative direction. The half-maximal activation voltage (V_0.5) was altered by −6.35 ± 1.53 and −1.95 ± 2.22 mV, respectively, with no major change in the slope factor (k). When myocytes were pretreated with Xamo, PE-induced reduction in I_Kr was markedly blunted and the corresponding change in V_0.5 was significantly altered. Similarly, when cells were pretreated with PE, Xamo-induced reduction of I_Kr was significantly attenuated. The present results demonstrate that functional cross-talk between α₁- and β₁-AR signaling regulates I_Kr. Such non-linear regulation may form a protective mechanism under excessive adrenergic stimulation.     

原发性高血压左心室肥厚患者脂蛋白磷脂酶 A2及脂联素检测的临床意义

目的：探讨原发性高血压左心室肥厚（LVH）患者脂蛋白磷脂酶 A2（Lp-PLA2）及脂联素的表达及临床意义。方法选择单纯原发性高血压病患者（A 组）及高血压 LVH 患者（B 组）各54例及同期健康对照者（C 组）55例,采用酶联免疫吸附试验（ELISA）法测定 Lp-PLA2及脂联素水平、免疫比浊法测定超敏 C 反应蛋白（hs-CRP）,采用心脏彩色多普勒超声诊断仪测量左心室质量指数（LVMI）;并对 B 组的血清 Lp-PLA2、脂联素及 hs-CRP 进行相关性分析。结果1）B 组 Lp-PLA2、hs-CRP 水平及 LVMI 高于 A 组和 C 组,脂联素水平低于 A 组（均 P ＜0．05）;A 组 Lp-PLA2、hs-CRP 水平及 LVMI 高于 C 组,脂联素水平低于 C 组（均 P ＜0．05）。2）高血压 LVH 患者Lp-PLA2与 hs-CRP 水平呈正相关（r＝0．875,P ＜0．05）,而二者水平均与脂联素无相关性。结论Lp-PLA2、脂联素及 hs-CRP 水平可作为高血压合并 LVH 患者评价病情严重程度的参考指标。     

院前应用胺碘酮治疗急性左心衰竭并发室性心律失常的疗效

目的探讨院前应用胺碘酮治疗急性左心衰竭并发室性心律失常的临床疗效和安全性。方法对65例急性左心衰竭并发室性心律失常患者均采用常规抗心力衰竭治疗。在此基础上,采用胺碘酮,首剂150 mg加入5%葡萄糖注射液20 mL中10 min内静脉推注完,随后以0.5～1 mg.min-1输液泵输注维持;若心律失常控制不满意,15 min后重复静脉推注150 mg。观察65例患者治疗前后心率（HR）、QT间期、血压（SBP、DBP）及室性心律失常和心功能的疗效、不良反应等情况。结果 65例患者中,室性心律失常治疗后的总有效率为86.2%,其中显效27例（41.5%）,有效29例（44.6%）,无效9例（13.8%）。治疗后HR较治疗前明显地减慢,差异有统计学意义[（67±11）次.min-1vs（103±8）次.min-1,P〈0.05]。治疗后QT间期、SBP、DBP与治疗前比较差异均无统计学意义（均P〉0.05）。心功能治疗后的总有效率为66.2%,其中显效14例（21.5%）,有效29例（44.6%）,无效22例（33.8%）。2例在静脉推注药物时出现低血压,经减慢静脉推注速度后血压上升。结论院前应用胺碘酮治疗急性左心衰竭并发室性心律失常有较好的疗效,是治疗急性左心衰竭并发室性心律失常的理想药物。     

Does Poor Vagal Tone Exacerbate Child Maladjustment in the Context of Parental Problem Drinking? A Longitudinal Examination.

Children's vagal tone was examined as a vulnerability factor in the longitudinal relation between mothers' (MPD) and fathers' (FPD) problem drinking and children's adjustment. At T1, MPD and FPD were examined, and children's vagal tone was assessed. Two years following initial participation, child adjustment problems were evaluated. A lower level of vagal tone was a vulnerability factor for internalizing problems associated with MPD and FPD and for externalizing difficulties associated with MPD. In the context of a higher level of MPD or FPD, a lower level of vagal tone was a vulnerability factor for increases in externalizing problems over time. Results are supportive of the importance of biopsychosocial perspectives in which child characteristics interact with family risk to predict psychopathology. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

心律失常心电图多媒体教学软件(ECG)的研究

从基础知识、自我测试和诊断训练三个方面介绍了研制的 ECG的软件功能 ,实现技术 ,以及在教学研究和临床实践中的推广应用情况。从三百个典型病例的实际情况介绍了通过心电图诊断病情 ,进而采取正确医疗措施治疗疾病的能力。该项成果在心电图教学软件上达到了国内领先水平     

门控心血池显像 LAO 采集角度和改变 LVROI 对心功能各项参数影响的研究

选取门控心血池检查患者１００例，就改变ＬＡＯ采集角度和ＬＶＲＯＩ对心功能各项参数的影响进行对比研究。结果显示ＬＡＯ４５°和操作者选定角度，用自动设置ＬＶＲＯＩ所获各项参数无显著性差异；而手动设置因所画ＲＯＩ大小不同ＥＤＶ差异显著，但其他各参数未见差异。因而提出ＬＡＯ４５°及自动设置为佳。     

Detection of premature ventricular contractions using MLP neural networks: A comparative study

This paper proposes a three stage technique for detection of premature ventricular contraction (PVC) from normal beats and other heart diseases. This method includes a denoising module, a feature extraction module and a classification module. In the first module we investigate the application of stationary wavelet transform (SWT) for noise reduction of the electrocardiogram (ECG) signals. The feature extraction module extracts 10 ECG morphological features and one timing interval feature. Then a number of multilayer perceptron (MLP) neural networks with different number of layers and nine training algorithms are designed. The performances of the networks for speed of convergence and accuracy classifications are evaluated for seven files from the MIT–BIH arrhythmia database. Among the different training algorithms, the resilient back-propagation (RP) algorithm illustrated the best convergence rate and the Levenberg–Marquardt (LM) algorithm achieved the best overall detection accuracy.     

一种新颖的永磁轴承及其在叶轮全人工心脏设计中的应用

研制了一种新颖的永磁轴承，由两个大小不同、充磁方向相同的同心磁环组成。将这种永磁轴承应用于叶轮式全人工心脏的结构设计，现已完成了样机制作和初步测试。耐久性试验已经持续14个月(进行中)，血泵流量和压力没有任何变化，电机驱动参数如电压、电流及转速也没有任何变化，表明泵内没有机械磨损。     

Structural arrangement of the cardiac collagen fibers of healthy and diabetic dogs

The heart is composed by a specialized muscle, whose form and function are essentials for an adequate work and shows an amount of connective tissue which support and provide insertion for this muscle, whose collagen fibers are responsible for determination of tissue feature. Our objective was to identify the structural arrangement of the heart collagen fibers in dogs. The hearts of the dogs were submitted to the process of the controlled digestion with NaOH solution and observed by scanning electron microscope. Our results showed that the collagen fibers of the endomysial wall have structural arrangement composed by an irregular network with one layer in normal dogs but in diabetic dogs the network acquires a greater amount of the fibers and layers, looking like a "rug" of fibers modifying the relationships of the stress/strain of the tissue. Ahead of the observed results we are able to conclude that exist increase in the amount and thickness of cardiac collagen fibers, beyond the increase of layers and architectural disarrangement in the endomysial wall in the diabetic dogs.