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21.
Di Xu Sen Wang Ting-Ting Wu Xiao-Yan Wang Jin Qian Yan Guo 《International journal of molecular sciences》2014,15(8):14220-14233
The rapidly activating delayed rectifier potassium current (IKr) plays a critical role in cardiac repolarization. Although IKr 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, IKr was recorded using the whole-cell patch-clamp technique. IKr 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 IKr by 0.22 ± 0.03 and 0.28 ± 0.01, respectively. The voltage-dependent activation curve of IKr shifted in the negative direction. The half-maximal activation voltage (V0.5) 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 IKr was markedly blunted and the corresponding change in V0.5 was significantly altered. Similarly, when cells were pretreated with PE, Xamo-induced reduction of IKr was significantly attenuated. The present results demonstrate that functional cross-talk between α1- and β1-AR signaling regulates IKr. Such non-linear regulation may form a protective mechanism under excessive adrenergic stimulation. 相似文献
22.
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。 相似文献
23.
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。 相似文献
24.
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) 相似文献
25.
心律失常心电图多媒体教学软件(ECG)的研究 总被引:1,自引:0,他引:1
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 相似文献
26.
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。 相似文献
27.
Detection of premature ventricular contractions using MLP neural networks: A comparative study 总被引:1,自引:0,他引:1
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. 相似文献
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30.
Benedicto HG Bombonato PP Macchiarelli G Stifano G Prado IM 《Microscopy research and technique》2011,74(11):1018-1023
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. 相似文献