草原公路纵坡上坡路段对驾驶员心电特性的影响研究

竖曲线是道路基本线形形式之一,并且是道路线形设计关键控制点。草原公路竖曲线具有变坡点多、坡长变化范围大的特点。本文通过偏相关分析方法确定草原公路纵坡路段影响驾驶员心电特性的线形要素为坡度,运用数理统计方法建立驾驶员心率增量与坡度的关系模型。得出在草原公路上坡路段当坡度为3.1%时,驾驶员心率增量达到最大值,驾驶员在此坡段精神负荷最大,疲劳感增强。

心肌电特性参数对心律影响的定量仿真研究

心电场是由心肌的电活动产生的。心肌细胞的电特性及心肌细胞间的传导关系决定了体表电位的分布及心电图的变化。心肌电特性参数主要包括动作电位、兴奋传导速度、不应期及心肌细胞受激时间间隔与动作电位持续时间的关系（间隔－时间关系）等。由于很难通过实验方法来人为改变这些参数，因而临床上有关心肌细胞电特性参数对心律影响的定量知识相当缺乏。本文采用真实三维躯干模型及心脏模型，对心肌电特性参数与心律变化的关系进行定量仿真研究。结果表明，动作电位的持续时间与Ｓ－Ｔ间隔有关；动作电位分布与Ｔ波形状有关；兴奋传导速度决定了整个心电图的变化，而局部普通心肌的传导速度在相当范围内变化似乎对心电图影响不明显，但传导速度超过一定范围后可能产生突变；心肌不应期的变化对心律也有影响，当某心肌单元不应期延长到一定程度后甚至可能引起折返；另外，心肌细胞受刺激时间间隔的长短对动作电位持续时间产生影响。

心肌干细胞移植可改进心力衰竭大鼠室颤阈值和电生理的稳定性

背景:心肌干细胞移植后是否引起或加重心肌梗死患者的心律失常是治疗的关键问题。目的:观察心肌干细胞对心力衰竭大鼠室颤阈值和电生理稳定性的影响。方法:开胸结扎20只SD大鼠左前降支冠状动脉,2周后选取其中的10只局部梗死心肌内注射PKH26荧光标记的由PBS悬浮的心肌干细胞,另10只局部梗死心肌内注射等量PBS。治疗6周后,再次开胸检测梗死边缘区的心电生理特性和室颤阈值。实验结束后,摘取心脏行病理切片,检查PHK26标记的心肌干细胞是否在梗死区内生存并表达连接蛋白43及α-肌动蛋白。结果与结论:与对照组相比,心肌干细胞移植组单极电图激动恢复时间及纠正的激动恢复时间明显缩短,电刺激所激发的恶性心律失常明显减少,室颤阈值明显提高。PHK26标记的心肌干细胞在梗死边缘区内被发现并表达连接蛋白43和α-肌动蛋白。提示心肌干细胞移植能改善心力衰竭大鼠心电生理的稳定性和提高室颤阈值;心肌干细胞可在体内表达心肌细胞和连接蛋白的标记。

心肌干细胞移植可短期内改善心肌梗死心电生理稳定性和提高室颤阈值

背景:课题组前期研究已证实心肌干细胞移植中期(6周)能有效改善心肌梗死大鼠的心电生理稳定性和室颤阈值。目的:比较心肌干细胞和骨髓间充质干细胞移植对心肌梗死大鼠心电生理学稳定性和室颤阈值的短期疗效差异。方法:取30只健康雄性SD大鼠,开胸结扎大鼠的左前降支冠状动脉建立心肌梗死动物实验模型,随机分成3组,分别为心肌干细胞移植组,骨髓间充质干细胞移植组,PBS对照组,每组10只。分别于建模成功2周后在梗死区心肌内局部注射0.1 m L PBS悬浮的5×106 PKH26标记的心肌干细胞、0.1 m L PBS悬浮的5×106 PKH26标记的骨髓间充质干细胞及0.1 m L PBS。植入2周后,再次开胸检测大鼠心脏梗死区、梗死边缘区、非梗死区的心电生理特性和室颤阈值。实验结束后,分离心脏梗死边缘区进行病理切片及荧光显微镜检查PHK26标记的心肌干细胞和骨髓间充质干细胞缝隙连接蛋白43表达情况。结果与结论:心肌干细胞移植组单极电图纠正的激动恢复时间离散度、电刺激所激发的恶性心律失常及梗死区、梗死边缘区、非梗死区的室颤阈值与PBS组、骨髓间充质干细胞移植组相比差异有显著性意义(P<0.05);骨髓间充质干细胞移植组单极电图纠正的激动恢复时间离散度及非梗死区的室颤阈值与PBS组相比差异有显著性意义。病理结果提示在心肌干细胞组、骨髓间充质干细胞组梗死边缘区发现有心肌干细胞、骨髓间充质干细胞的存在。通过组织免疫荧光检测,PKH26标记的心肌干细胞表达较多的缝隙连接蛋白43,而PKH26标记的骨髓间充质干细胞很少表达缝隙连接蛋白43,PBS组不表达缝隙连接蛋白43。上述结果提示心肌干细胞移植短期内心电生理学特性改善的效应较骨髓间充质干细胞优越,且改善效应与缝隙连接蛋白43相关。

心肌干细胞调控ANG Ⅱ/AT1R/TGF-β1/SMAD/CX43通路改进心电生理学稳定性和室颤阈值

背景:课题组前期研究证实心肌干细胞移植中期(6周)能有效改善心肌梗死大鼠的心电生理稳定性和室颤阈值,但具体的调控机制和通路不明。目的:探讨心肌干细胞改善心肌梗死大鼠心电生理学稳定性和室颤阈值的相关分子调控机制。方法:通过开胸结扎20只SD大鼠左前降支冠状动脉建立心肌梗死模型,并随机分为2组:心肌干细胞组和PBS组,每组10只。造模后2周心肌干细胞组在局部梗死心肌内注射PKH26标记的由PBS悬浮的心肌干细胞,PBS组在梗死心肌内注射等量PBS。细胞移植后6周取外周血及左心室心肌组织检测ANGⅡ/AT1R/TGF-β1/SMAD/Cx43通路相关因子的变化。结果与结论:(1)与PBS组相比,Cx43在心肌干细胞组梗死区、梗死边缘区、非梗死区的表达明显增加(P<0.01);(2)与PBS组相比,ANGⅡ在心肌干细胞组血浆(P<0.05)和左心室各区域(P<0.01)的表达明显减少;(3)与PBS组相比,心肌干细胞组左心室心肌组织不同区域AT1R、TGF-β1、SMAD2、SMAD3表达下降(P<0.01),而SMAD7表达增加(P<0.05);(4)结果表明,心肌干细胞移植改善心肌梗死大鼠的心电生理学稳定性和室颤阈值的机制可能与调控ANGⅡ/AT1R/TGF-β1/SMAD/CX43通路,导致CX43表达增加密切相关。

心肌干细胞移植心肌梗死区12周后的心电生理稳定性及室颤阈值改善效应

背景:课题组前期研究证实心肌干细胞治疗心肌梗死后短中期(6周)能明显改善心电生理学稳定性和室颤阈值。目的:观察心肌干细胞对心力衰竭大鼠室颤阈值和心电生理稳定性的长期影响。方法:开胸结扎20只SD大鼠左前降支冠状动脉,2周后其中10只大鼠局部梗死心肌内注射PKH26荧光标记的由PBS悬浮的心肌干细胞,另10只大鼠局部梗死心肌内注射等量PBS。治疗12周后,再次开胸检测梗死区、梗死边缘区和非梗死区的心电生理特性和室颤阈值。实验结束后,摘取心脏行病理切片,检查PHK26标记的心肌干细胞是否在梗死区内生存并表达连接蛋白43及α-肌动蛋白。结果与结论:与对照组相比,心肌干细胞移植12周后其梗死区、梗死边缘区和非梗死区的单极电图激动恢复时间、纠正的激动恢复时间差异无显著性意义(P>0.05);单极电图纠正的激动恢复时间离散度、电刺激所激发的恶性心律失常差异无显著性意义(P>0.05);室颤阈值方面,实验组梗死区和梗死边缘区与对照组相比差异无显著性意义(P>0.05),非梗死区与对照组相比差异有显著性意义(P<0.05)。PHK26标记的心肌干细胞在梗死边缘区内被发现并表达连接蛋白43和α-肌动蛋白。以上结果提示心肌干细胞移植后12周其心电生理的稳定性和室颤阈值的改善效应已逐渐消失,但机制未明。

心房颤动对心房肌细胞的影响

本文综述了心房颤动对心房肌细胞的离子通道。

心肌干细胞和骨髓间充质干细胞改进心肌梗死大鼠室颤阈值和心电生理稳定性的对比研究

目的 比较心肌干细胞（cardiac stem cells,CSCs）和骨髓间充质干细胞（mesenchymal stem cells,MSCs）对心肌梗死（myocardial infarction,MI）大鼠室颤阈值和心电生理学稳定性的影响.方法 通过开胸结扎30只SD大鼠左前降支冠状动脉建立心肌梗死模型,2周后随机（随机数字法）分为CSCs组、MSCs组及PBS组,每组各10只,分别于局部梗死心肌内注射PKH26荧光标记的CSCs、MSCs或等量PBS.治疗6周后,再次开胸检测梗死边缘区的心电生理特性和室颤阈值.实验结束后,摘取心脏行病理切片,检查PKH26标记的CSCs、MSCs是否在梗死边缘区内生存并表达连接蛋白43.结果 CSCs组移植6周后其梗死边缘区单极电图激动恢复时间、纠正的激动恢复时间与MSCs组及对照组比较,差异无统计学意义（P＞0.05）;CSCs组梗死边缘区单极电图纠正的激动恢复时间离散度、电刺激所激发的恶性心律失常及室颤阈值与MSCs组及对照组比较,差异具有统计学意义（P＜0.05）;在上述指标方面,MSCs组和PBS组比较,均差异无统计学意义（P＞0.05）.PKH26标记的CSCs在梗死边缘区内被发现并表达连接蛋白43,而PKH26标记的存在于梗死边缘区的MSCs则很少表达连接蛋白43.结论 CSCs移植和MSCs移植治疗心肌梗死是比较安全有效的,无明显致心律失常性.CSCs移植后6周其心电生理学稳定性改善和室颤阈值提高的效应较MSCs优越,CSCs是治疗心血管疾病较为理想的种子细胞.

The role of electrocardiography in the elaboration of a new paradigm in cardiac resynchronization therapy for patients with nonspecific intraventricular conduction disturbance

Cardiac resynchronization therapy （CRT） is associated with a favorable outcome only in patients with left bundle branch block （LBBB） pattern and in patients with a QRS duration 〉 150 ms, in patients with non-LBBB pattern with a QRS duration of 120-150 ms usually is not beneficial. After adjusting for QRS duration, QRS morphology was no longer a determinant of the clinical response to CRT. In contrast to the mainstream view, we hypothesized that the unfavorable CRT outcome in patients with non-LBBB and a QRS duration of 120-150 ms is not due to the QRS morphology itself, but to less dyssynchrony and unfavorable patient characteristics in this subgroup, such as more ischemic etiology and greater prevalence of male patients compared with patients with LBBB pattern. Further, the current CRT technique is devised to eliminate the dyssynchrony present in patients with LBBB pattern and inappropriate to eliminate the dyssynchrony in patients with non-LBBB pattern. We also hypothesized that electrocardiography may also provide information about the presence of interventricular and left intraventricular dyssynchrony and the approximate location of the latest activated left ventricular （LV） region. To this end, we devised new ECG criteria to estimate interventricular and LV intraventricular dyssynchrony and the approximate location of the latest activated LV region. Our preliminary data demonstrated that the latest activated LV region in patients with nonspecific intraventricular conduction disturbance （NICD） pattern might be at a remote site from that present in patients with LBBB pattern, which might necessitate the invention of a novel CRT technique for patients with NICD pattern. The application of the new interventricular and LV intraventricular dyssynchrony ECG criteria and a potential novel CRT technique might decrease the currently high nonresponder rate in patients with NICD pattern.

Age-related increase of early afterdepolarization in calsequestrin-2 knock-in mouse cardiomycyte

Objective To characterize early afterdepolarizations （EADs） caused triggered activity （TA） among calsequestrin-2 （CASQ2） knock-in （CASQ2 KI） mice and its relationship with aging. Methods Electrophysiological properties of ventricular myocytes from 3- month （mo, young）, 9-mo （adult-l） and 12-too （adult-2） in wild-type （WT） and CASQ2 KI mice were investigated with patch-clamp technique. Results The incidences of EADs and TA in CASQ2 KI cardiomyocytes increased with increasing age. In contrast, WT mice cardiomyocytes showed no significant change in matched-age groups. Compared with that in 3-mo CASQ2 KI mice, the 50% repolarization of action potential （APD50） showed prolongation in both 9-mo and 12-mo ones （9.2±0.9 ms of 9-mo and 10.3 ± 1.2 ms of 12- mo vs. 5.6± 0.3 ms of 3-mo）, while the 90 % repolarization of action potential （APD90） was similar among 3 age groups. Compared with 3-mo mice, the 9-mo and 12-mo CASQ2 KI mice showed markedly reduced transient outward potassium current （Ito） densities but increased L-type calcium current （ICa-L） densities. Conlcusion This study suggested that events of EADs and TA in CASQ2 KI mice increased with increasing age, It might be associated partly with the augment of cellular calcium concentration and the prolongation of APD50 induced by decrease of Ito and increase of ICa-L in adult CASQ2 KI mice

Rebellion and Remodeling of individual consciousness for Contemporary Collective Memory ——Taking Online Movie as an Example

In this paper, the network movie as the research object, quoted in the theory of ＂collective memory＂ from Mauric Halbwachs, the academic circles in recent years on the Internet Movie different viewpoint for reference, consult a lot of literatures, the method of interdisciplinary research in the field of psychology, culture, to ＂memory＂, ＂culture＂, ＂group （SOCIAL）＂ in three aspects, analysis of network movie as an expression of individual consciousness, contradiction between individual and collective in the expression of the collective memory of the film, through the analysis of the network specific expression, expression, the expression of an important role in the formation of rebellious sense for people aesthetic psychology, the awakening of individual consciousness and group identity. Therefore, it is necessary to culture the appearance and development of Internet Movie, is bound to the mode of expression, the people＇s cultural psychology and social individual to collective identity have significant influence.

Effect of metal centres and substituents on the structure and optoelectronic properties of diarylethene compounds:A theoretical study

Diarylethene derivatives are a class of fascinating photochromic materials because of their open and closed isomers with different absorption spectra and many other characteristics.To reveal the detailed structure and optoelectronic properties as well as the effect of metal centres and substituents on them,a systematic study on a series of diarylethene derivatives and their Re(I),Pt(II),and Ir(III) complexes was performed via theoretical calculation.The optimized geometries,electronic properties,frontier molecular orbitals,ionization potentials,electron affinities,reorganization energies,and absorption spectra for both of their open-and closed-isomers have been calculated and analyzed.Metal-coordination and substituents exhibit great influence on the photophysical,charge-injection and-transporting characteristics.In addition,the binding of F-with the boron atom of dimesitylboryl group through Lewis acid/base interactions also induces great changes of structural,photophysical and electronic properties for these diarylethene derivatives,and consequently the compound with the substituent of dimesitylboryl group can be used as selective near-infrared phosphorescent F-probe.

Distribution and characteristics of telocytes as nurse cells in the architectural organization of engineered heart tissues

Interstitial Cajal-like cells are a distinct type of interstitial cell with a wide distribution in mammalian organs and tissues,and have been given the name"telocytes".Recent studies have demonstrated the potential roles of telocytes in heart development,renewal,and repair.However,further research on the functions of telocytes is limited by the complicated in vivo environment.This study was designed to construct engineered heart tissue(EHT)as a three-dimensional model in vitro to better understand the role of telocytes in the architectural organization of the myocardium.EHTs were constructed by seeding neonatal cardiomyocytes in collagen/Matrigel scaffolds followed by culture under persistent static stretch.Telocytes in EHTs were identified by histology,toluidine blue staining,immunofluorescence,and transmission electron microscopy.The results from histology and toluidine blue staining demonstrated widespread putative telocytes with compact toluidine blue-stained nuclei,which were located around cardiomyocytes.Prolongations from the cell bodies showed a characteristic dichotomous branching pattern and formed networks in EHTs.Immunofluorescence revealed positive staining of telocytes for CD34 and vimentin with typical moniliform prolongations.A series of electron microscopy images further showed that typical telocytes embraced the cardiomyocytes with their long prolongations and exhibited a marked appearance of nursing cardiomyocytes during the construction of EHTs.This finding highlights the great importance of telocytes in the architectural organization of EHTs.It also suggests that EHT is an appropriate physical and pathological model system in vitro to study the roles of telocytes during heart development and regeneration.

Complexity and characteristic frequency studies in ECG signals of mice based on multiple scale factors

Existing methods of physiological signal analysis based on nonlinear dynamic theories only examine the complexity difference of the signals under a single sampling frequency.We developed a technique to measure the multifractal characteristic parameter intimately associated with physiological activities through a frequency scale factor.This parameter is highly sensitive to physiological and pathological status.Mice received various drugs to imitate different physiological and pathological conditions,and the distributions of mass exponent spectrum curvature with scale factors from the electrocardiogram (ECG) signals of healthy and drug injected mice were determined.Next,we determined the characteristic frequency scope in which the signal was of the highest complexity and most sensitive to impaired cardiac function,and examined the relationships between heart rate,heartbeat dynamic complexity,and sensitive frequency scope of the ECG signal.We found that all animals exhibited a scale factor range in which the absolute magnitudes of ECG mass exponent spectrum curvature achieve the maximum,and this range (or frequency scope) is not changed with calculated data points or maximal coarse-grained scale factor.Further,the heart rate of mice was not necessarily associated with the nonlinear complexity of cardiac dynamics,but closely related to the most sensitive ECG frequency scope determined by characterization of this complex dynamic features for certain heartbeat conditions.Finally,we found that the health status of the hearts of mice was directly related to the heartbeat dynamic complexity,both of which were positively correlated within the scale factor around the extremum region of the multifractal parameter.With increasing heart rate,the sensitive frequency scope increased to a relatively high location.In conclusion,these data provide important theoretical and practical data for the early diagnosis of cardiac disorders.

Experimental Study on the Influence of Electroacupuncture on Cardiac Sympathetic Nerve Activity and Cardiac Function in Acute Myocardial Ischemia Rabbits

Objective： To observe the influence of electroacupuncture （EA） of different Yuan- Primary acupoints on cardiac sympathetic nerve activity （CSNA） and cardiac function in rabbits with acute myocardial ischemia （AMI）, and to understand the interaction mechanisms of cardiac sympathetic nerve in adjusting acute myocardial ischemia. Method： A total of forty healthy rabbits were selected and 8 were randomly chosen as normal control. The rest 32 rabbits were inducted acute myocardial ischemia （AMI） models by intravenous Pituitrin, then the AMI model rabbits were randomly divided into 4 groups, 8 as model group, and 8 as EA on Shenmen （HT 7） group, 8 as EA on Taixi （K/3） group, and 8 as EA on nonpoint group. BIOPAC collection system of biological signal was used to record the changes of CSNA and cardiac function, and the data was analyzed using a SKY-A8 disposal system. Result： The lefl ventricular systolic peak pressure （LVSP）, maximum rate of rise of LVSP （＋dp/dt max） descended obviously, and maximum rate of descent of LVSP （-dp/dt max） ascended after induction of AMI. The ＋dp/dt max, -dp/dt max and LVSP of EA on Shenmen （HT 7） group are significantly higher than the untreated AMI group, EA on Taixi （KI 3） group and EA on nonpoint group after EA. The frequency of cardiac sympathetic nerve activity increased significantly after induction of AMI, and then decreased sharply （compared with that of normal group, P〈0.05）. Following EA, the cardiac sympathetic nerve activity of EA on Shenmen （HT 7） group are significantly higher than the model group, EA on Taixi （KI 3） group and EA on nonpoint group. And they have no significant difference with normal group. Conclusion： EA on Shenmen （HT 7） could improve the cardiac function and cardiac sympathetic nerve activity of rabbits with AMI, and promote the restoration of cardiac function. There is specificity in the effects of EA on different Yuan-Primary acupoints with the best effect on Shenmen （HT 7）, and no effect on Taixi （KI 3） and nonpoint. EA on related acupoint can adjust the cardiac sympathetic nerve activity, and may moderate the effects of myocardial ischemia. The sympathetic nerve is one of the key periphery ways in using acupuncture against myocardial ischemia.