动态心电图及其与射血分数值、心室晚电位对心肌梗塞病人恶性室性心律失常的预测意义

本文探讨了动态心电图及其与左室射血分数（ＬＶＥＦ）、心室晚电位（ＶＬＰ）联合对心肌梗塞（ＭＩ）病人稳定期以后发生恶性室性心律失常事件（ＭＶＡＥ）的预测意义。分别对９５例ＭＩ稳定期以后的病人行Ｈｏｌｔｅｒ、ＬＶＥＦ、ＶＬＰ检测。结果显示Ｈｏｌｔｅｒ等各单项检查阳性组分别比各相应单项检查阴性组ＭＶＡＥ的发生率高；如多项检查均阳性者发生率更高。本文结果揭示Ｈｏｌｔｅｒ、ＬＶＥＦ、ＶＬＰ的联合应用能提高预测的可靠性和准确性，并为临床预测ＭＩ病人稳定期后发生ＭＶＡＥ的可能性提供一种方法。     

急性心肌梗塞伴心律失常患者心室晚电位与肌酸激酶的关系

作者报道急性心肌梗塞（ＡＭＩ）患者早期（一周内）伴有室性心律失常（ＶＡ）４４例，其心室晚电位（ＶＬＰ）阳性率２９．５％与血清肌酸激酶（ＣＫ）及同功酶（ＣＫ－ＭＢ）峰值呈正相关；与年龄，性别，心梗部位无关。室速（ＶＴ）和室颤（ＶＦ）组的ＶＬＰ阳性率明显高于室早组（Ｐ＜０．０５）。但两组的ＣＫ，ＣＫ－ＭＢ比值无统计学意义。     

心率变异预测急性心肌梗死预后的价值

为探讨急性心肌梗死（ＡＭＩ）预后与心率变异（ＨＲＶ）的关系及ＨＲＶ与左室射血分数（ＬＶＥＦ）、心室晚电位（ＶＬＰ）联合应用对心律失常事件的预测价值，对８４例ＡＭＩ后两周的患者进行ＨＲＶ时域及频域分析和ＶＬＰ检测，并进行长期随访。平均随访１６．７５±７．７４（４～２９）个月（１２例失访）。结果表明：①发生严重心律失常事件的ＡＭＩ患者（１５例）的ＨＲＶ较无严重心律失常事件者（５７例）明显下降〔ＳＤ：３．８７９±０．３５５ｌｎ（ｍｓ）ｖｓ４．０７７±０．２８１ｌｎ（ｍｓ），Ｓｔ．Ｇｅｏｒｇｅｓ指数：３．６７７±０．５６９ｖｓ３．９２９±０．３５８，ＬＦ：４．３９９±１．１７９ｌｎ（ｍｓ２／Ｈｚ）ｖｓ５．０４１±０．９１２ｌｎ（ｍｓ２／Ｈｚ），Ｐ均＜０．０５〕。②ＨＲＶ对严重心律失常事件预测的敏感性为４６．７％，高于ＬＶＥＦ（３３．３％）及ＶＬＰ（２６．７％）；阳性预测值为３０．４％，与ＬＶＥＦ（３１．２％）及ＶＬＰ（３０．８％）相近。③ＨＲＶ分别与ＬＶＥＦ、ＶＬＰ合用，可明显提高阳性预测值（依次为６０％和５０％）。提示ＡＭＩ后心律失常事件的发生及心脏性猝死与ＨＲＶ有密切关系。     

电生理检查对急性心肌梗塞后心室晚电位阳性预测室性心律失常发生及猝死的价值

本研究的目的是对急性心肌梗塞（ＡＭＩ）后心室晚电位（ＶＬＰ）阳性５０例，于第７天做电生理检查来预测ＡＭＩ有无室性心律失常的发生及猝死。程序电刺激诱发出单形持续性室速１５例（３０％），室颤４例（８％），无心律失常发生３１例（６２％）。经６～１２月随访，结果示：电生理检查阳性预测室性心律失常事件（简称事件）发生准确率为９４．４％，发生事件１８例，其中电生理检查阳性者１７例，表明ＶＬＰ阳性加电生理检查阳性日后发生事件远比ＶＬＰ阳性但电生理检查阴性者高（分别为９４．４％和５．６％，Ｐ＜０．００１）。通过本研究证实，两者结合起来对预测ＡＭＩ事件及猝死的发生更为准确，同时有着重要的临床意义。     

信号平均心电图预测冠心病患者心律失常事件的前瞻性研究

目的：评价心室晚电位（ＶＬＰ）预测心律失常事件（ＡＥ）的价值。方法：对２６１例冠心病患者进行２４小时Ｈｏｌｔｅｒ和信号平均心电图（ＳＡ－ＥＣＧ）检测，其中ＡＭＩ患者于发病后２～４周行ＳＡ－ＥＣＧ检测。所有患者均进行临床随访。结果：２６１例冠心病患者中ＶＬＰ阳性率１４９％，随访１３６±６９（４～３６）月，发生ＡＥ１８例。ＶＬＰ阳性组ＡＥ发生率２９７％，明显高于ＶＬＰ阴性组ＡＥ发生率３６％（Ｐ＜００００１）。发生ＡＥ组ＶＬＰ阳性率６１１％，明显高于未发生ＡＥ组ＶＬＰ阳性率１２３％（Ｐ＜０００１）。ＶＬＰ时域分析预测冠心病患者发生ＡＥ的敏感性６１１％、特异性８７７％、阳性预测值２９７％、阴性预测值９６４％、准确性８５６％。结论：ＶＬＰ预测ＡＥ有较高的敏感性、特异性和准确性。ＶＬＰ有助于冠心病（尤其心肌梗死）患者的危险性分层。     

恶性室性心律失常药物治疗中的一些问题

恶性室性心律失常药物治疗中的一些问题胡大一许玉韵１恶性室性心律失常的一级预防恶性室性心律失常〔持续性室性心动过速或（和）心室颤动（ＶＴ／ＶＦ）〕的一级预防对象即是临床上尚未发生过此类心律失常的病人。心肌梗死（简称心梗）后的病人如无使用β－受体阻断剂的...     

老年冠心病患者心室晚电位5年随访观察

老年冠心病患者心室晚电位５年随访观察王卫东徐岩心室晚电位（ＶＬＰ）是出现在ＱＲＳ波终末或ＳＴ段的高频低幅碎裂电位，临床多用来预测冠心病心肌梗死（ＭＩ）的心律失常事件。缺血性心脏病可以发生持续性室速、室颤和猝死，为观察ＶＬＰ检测在预测无ＭＩ病史老年心绞...     

心室晚电位心率变异对急性心肌梗死者心律失常事件发生 ...

目的 通过４０例急性心肌梗死（ＡＭＩ，Ａ组）者的心室晚电位（ＶＬＰ）、心率变异（ＨＲＶ）检测，与４０例正常人（Ｂ组）进行对比。结果 Ａ组ＨＲＶ（ＳＤＮＮ）较Ｂ组明显缩小（Ｐ〈０．００１），ＶＬＰ阳性率明显增加（Ｐ〈０．０１）。室性心律失常（ＶＴ）事件组（Ａ１组）与非事件组（Ａ２组（的２项指标比较有非常显著差异（Ｐ〈０．００５）并且ＨＲＶ特异性同。结论 ２者同时监测可增加预测指标的特异性、有效性及相     

急性心肌梗塞患者心率变异性与心室晚电位和左室射血分数以及室性心律失常关系的探讨

采用动态心电图统计２４小时全部窦性ＲＲ间期，以测定３０例急性心肌梗塞（ＡＭＩ）后１７±４ｄ的心率变异性（ＨＲＶ）ＲＲ间期均值的标准差（ＳＤ）指标，并同时测定心室晚电位（ＶＬＰ）、左室射血分数（ＬＶＥＦ）和用Ｈｏｌｔｅｒ记录室性心律失常，分析它们之间的关系。ＶＬＰ阳性与阴性组的ＨＲＶ无显著性差异（Ｐ＞０．０５）；ＨＲＶ与ＬＶＥＦ呈显著正相关（Ｐ＜０．００５）；Ｈｏｌｔｅｒ记录到短阵室性心动过速、成对室性早搏（简称室早）和每小时室早数＞１００次的ＳＤ值显著低于未记录到室早和每小时室早数＜１０次者（Ｐ＜０．００１）。提示ＡＭＩ后ＨＲＶ降低与ＶＬＰ阳性与否无关；低ＬＶＥＦ者ＨＲＶ亦降低；ＨＲＶ降低者其室性心律失常发生率显著增加。联合应用上述方法和指标，可望提高对ＡＭＩ后高危患者预测的准确率。     

频域法心率变异检测与急性心肌梗死室速的关系

频域法心率变异检测与急性心肌梗死室速的关系ＶａｌｒａｍａＪＯ···／ＩｎｔＪＣａｒｄｉｏｌ１９９３；３８：１７７－１８２目前关于心律变异（ＨＲＶ）的瞬时变化及其和恶性心律失常的关系报道甚少。本文分析了急性心肌梗死（ＡＭＩ）中室速（ＶＴ）发作前及发作时...     

Time domain parameters can be estimated with less statistical error than frequency domain parameters in the analysis of heart rate variability

Introduction

Measures of heart rate variability (HRV) can be divided in time domain and frequency domain parameters. It is frequently ignored that estimation of frequency-domain parameters is a 2-step procedure where statistical error from the first step (spectral estimation) is neglected in subsequent analyses.

Methods

We performed a simulation study to quantify the statistical error by using frequency domain instead of time domain parameters. We generated tachograms from a stationary AR(1) process for a wide range of parameters and compared the resulting estimation error (in terms of precision and variability) for the standard deviation of normal RR intervals (SDNN) and low frequency (LF), high frequency (HF), and LF/HF power.

Results

Estimation of frequency domain parameters is associated with (up to 10-fold) increased variability, as compared with the SDNN. Moreover, the SDNN has higher precision.

Conclusion

Frequency domain parameters should be applied in HRV analysis only if important physiological reasons suggest their use. If used, frequency domain parameters should be interpreted with caution, taking into account the statistical weaknesses of spectral estimation.     

N-terminal domain of vacuolar SNARE Vam7p promotes trans-SNARE complex assembly

SNARE-dependent membrane fusion in eukaryotic cells requires that the heptad-repeat SNARE domains from R- and Q-SNAREs, anchored to apposed membranes, assemble into four-helix coiled-coil bundles. In addition to their SNARE and transmembrane domains, most SNAREs have N-terminal domains (N-domains), although their functions are unclear. The N-domain of the yeast vacuolar Qc-SNARE Vam7p is a binding partner for the homotypic fusion and vacuole protein sorting complex (a master regulator of vacuole fusion) and has Phox homology, providing a phosphatidylinositol 3-phosphate (PI3P)-specific membrane anchor. We now report that this Vam7p N-domain has yet another role, one that does not depend on its physical connection to the Vam7p SNARE domain. By attaching a transmembrane anchor to the C terminus of Vam7p to create Vam7tm, we bypass the requirement for the N-domain to anchor Vam7tm to reconstituted proteoliposomes. The N-domain of Vam7tm is indispensible for trans-SNARE complex assembly in SNARE-only reactions. Introducing Vam7(1-125)p as a separate recombinant protein suppresses the defect caused by N-domain deletion from Vam7tm, demonstrating that the function of this N-domain is not constrained to covalent attachment to Vam7p. The Vam7p N-domain catalyzes the docking of apposed membranes by promoting transinteractions between R- and Q-SNAREs. This function of the Vam7p N-domain depends on the presence of PI3P and its affinity for PI3P. Added N-domain can even promote SNARE complex assembly when Vam7 still bears its own N-domain.     

Characterization,stability, and application of domain walls in flexible mechanical metamaterials

Domain walls, commonly occurring at the interface of different phases in solid-state materials, have recently been harnessed at the structural scale to enable additional modes of functionality. Here, we combine experimental, numerical, and theoretical tools to investigate the domain walls emerging upon uniaxial compression in a mechanical metamaterial based on the rotating-squares mechanism. We first show that these interfaces can be generated and controlled by carefully arranging a few phase-inducing defects. We establish an analytical model to capture the evolution of the domain walls as a function of the applied deformation. We then employ this model as a guideline to realize interfaces of complex shape. Finally, we show that the engineered domain walls modify the global response of the metamaterial and can be effectively exploited to tune its stiffness as well as to guide the propagation of elastic waves.

The coexistence of two or more phases plays a central role in many ordered solid-state materials, including ferroelectrics (1–3), ferromagnets (4, 5), ferroelastics (6, 7), shape memory alloys (7, 8), and liquid crystals (9). Despite being intrinsically different, these materials all share the emergence of domain walls—a type of topological defect that separates regions of different phases (10). Such interfaces are crucial for the control of many material properties, including coercivity, resistance, and/or fatigue (11), and have also been exploited to enable logic operations (12), racetrack memory (13), and line scanners for reading optical memories (14). Inspired by the recent advancements in domain walls control strategies at the atomistic scale, researchers have designed a variety of nonlinear mechanical structures to support these interfaces (15–25). Domain walls engineered at the structural scale have facilitated the control of elastic pulses (16, 17, 19, 25), the encryption of information (23), and the realization of deployable structures (20) as well as of phase-transforming metamaterials (15, 18). However, due to the structural complexity of mechanical metamaterials, no analytical solution has been proposed that fully describes the physics of such domain walls. This limits their systematic application in the design of smart structures and devices and hinders the discovery of additional functionalities.Here, we use a combination of experiments and analyses to study the domain walls emerging in a mechanical metamaterial based on the rotating-squares mechanism. We start by introducing defects into the system to locally impose nucleation of one of the two supported buckling-induced rotated phases upon compression. Importantly, when such defects lead to the coexistence of two phases within the specimen, domain walls form, across which the angle of individual squares switches from one direction of rotation to the other. We establish an analytical model that fully describes the emerging domain walls, including their profile and position as a function of the applied deformation. Guided by our model, we then introduce pinning defects to reshape the energy landscape of the system and, therefore, engineer domain walls along arbitrary complex paths. Based on our findings we foresee the exploitation of domain walls in the realm of mechanical metamaterials to realize additional functionalities, as we hereby demonstrate by achieving stiffness tuning and reconfigurable elastic wave guiding.     

Heart rate variability in sarcoidosis: a frequency domain analysis

BACKGROUND: Little is known about autonomic dysfunction in patients with sarcoidosis. Heart rate variability (HRV) studies provide information regarding sympathetic and vagal tone and are both noninvasive and relatively simple to perform. The objective of this study was to compare HRV in sarcoidosis patients and in healthy controls. METHODS: We prospectively analyzed data from 12 sarcoidosis patients and 12 healthy volunteers. Electrocardiographic (ECG) data were recorded from all study participants, and HRV analysis was performed in the frequency domain. The sarcoidosis patients underwent echocardiography as well. RESULTS: Mean values for HRV in the high-frequency (HF) domain were significantly reduced in sarcoidosis patients (182+/-102 ms(2) vs. 758+/-457 in controls, p=0.001). We also observed a trend (p=0.055) towards an increased ratio of low-frequency (LF) to high-frequency power in sarcoidosis patients. CONCLUSIONS: Our findings indicate the possibility of altered sympathovagal balance in sarcoidosis. Since 5 of these 12 sarcoidosis patients had mild echocardiographic abnormalities, possibly related to sarcoidosis, we were unable to conclude whether the HRV findings were attributable solely to an autonomic dysfunction in sarcoidosis or whether they were related to a structural myocardial involvement of the disease.     

健康人心率变异时域法正常值分析

为了解国人心率变异(HRV)时域法指标正常值,检测1524例17—94岁健康人24h动态心电图,分析HRV时域法5项指标。结果显示:(1)SDNN、SDANN、SDNN_(Index),rMSSD和PNN_(50)均值分别为127±33、116±32、49±14、29±12(ms)和8±9％,与国内研究一致。(2)HRV时域法各指标随年龄增加而降低(r=0.30——0.48,P<0.01),中青年组与老年组HRV差异有显著意义(P<0.01)。(3)男性SDNN、SDANN和SDNN_Index大于女性(P<0.05),而rMSSD和PNN_(50)小于女性(P<0.05)。SnNN、SDANN、SDNN_(Index)和rMSSD单侧下限值分别为73、64、26和9ms,PNN_(50)呈偏态分布,临床意义有待探讨。     

新型疫苗佐剂Ov-ASP-1佐剂活性功能区的设计、表达及生物学特性研究

目的 获得保留Ov-ASP-1佐剂活性的功能区。方法 用前期制备的Ov-ASP-1单克隆抗体对Ov-ASP-1的9个肽进行特异性结合,根据肽的结合情况设计功能区ASPPRM,并进行密码子优化、构建原核表达载体后在大肠杆菌中表达。表达产物经 Western印迹鉴定后的用镍柱纯化蛋白,复性完全后对获得的ASPPRM活性蛋白进行生物学特性分析。结果 ASPPRM以包涵体形式表达,分子量为17 kD。将其和OVA共同免疫小鼠后ASPPRM组抗OVA的IgG抗体显著高于OVA组。结论 本研究获得了保留佐剂活性的ASPPRM蛋白,为后续ASPPRM体内的免疫增效作用及Ov-ASP-1佐剂活性功能域的探索奠定基础。     

Distinct Grb10 domain requirements for effects on glucose uptake and insulin signaling

The adapter protein Grb10 binds to phosphotyrosine residues in insulin receptors via its C-terminal region and regulates insulin signaling. This study investigated Grb10 regulation of glucose uptake and the importance of the Grb10 N-terminal region using 3T3-L1 adipocytes overexpressing full-length (FL-Grb10) or N-terminally truncated Grb10 (BPS-SH2). Overexpression of FL-Grb10 inhibited insulin-stimulated receptor autophosphorylation and glucose uptake. In contrast, the BPS-SH2 fragment of Grb10 had no effect on receptor phosphorylation or glucose uptake. In spite of these differences, both FL-Grb10 and the BPS-SH2 fragment inhibited insulin-stimulated phosphorylation of IRS1, IRS2, Akt/PKB, Shc, ERK1/2, APS, and c-Cbl to a similar extent. Co-precipitation studies demonstrated more sustained binding of the BPS-SH2 fragment than FL-Grb10 to insulin receptors. Although receptor binding domains of Grb10 are sufficient to inhibit insulin effects on proximal post-receptor signaling responses, N-terminal domains of Grb10 are essential for the effects of this adapter protein on receptor phosphorylation and glucose uptake.     

SARS-CoVSpike蛋白受体结合区的表达及纯化

目的获得稳定表达SARS冠状病毒spike蛋白受体结合区的果蝇细胞系,表达spike蛋白受体结合区。方法设计引物扩增spike蛋白受体结合区318-513片段,构建重组表达载体S318-pMT/Bip/V5-his,与pCoBlast质粒共转染果蝇S2细胞,经Blasticidin筛选得到的稳定重组细胞系,用硫酸铜诱导表达,Western-Blot检测表达产物。富集的表达产物用镍柱和RESOURCES阳离子交换树脂纯化,SDS-PAGE和Western-Blot检测纯化产物。结果重组spike蛋白受体结合区可在果蝇S2细胞中分泌表达,且具有特异免疫反应性;经镍柱和RESOURCES纯化可得到纯度达90%以上的重组蛋白。结论克隆并在真核生物中分泌表达出具免疫反应原性的spike蛋白受体结合区,镍柱和RESOURCES两步纯化可得到高纯度蛋白。