非风湿性房颤患者经不同药物复律后左房功能改变的超声对比研究1

目的 比较非风湿性房颤(NRH-AF) 患者经胺碘酮和心律平复律后左房收缩功能的改变。 方法 利用多普勒超声观察了25 患者分别服用胺碘酮(简称胺碘酮组, n =13) 和心律平(心律平组, n =15) 复律后d 1、d 30 时的房缩期二尖瓣血流(MIF) 和肺静脉血流(PVF) 变化, 并与15 例正常人作对比。 结果 两组患者复律后d 1 的房缩期二尖瓣血流峰速(Ap), 速度积分(Ai) 和房缩期肺静脉返转血流峰速(Zp), 速度积分(Zi) 均较正常显著减小(P <0.01), 但两组之间无显著性差异。此后4 wk 内两组患者的Ap、Ai、Zp 和Zi 均逐步增大, 但复律后d30 时两组患者的Ap、Ai、Zp 和Zi 都较正常组显著减小。与胺碘酮组患者相比, 心律平组d 30 时的Ap、Ai、Zp 和Zi 均显著减小(P <0.05)。 结论 NRH-AF患者经胺碘酮或心律平复律后一个月内左房收缩功能均不能完全恢复, 且两组间改善程度不同, 从复律后左房机械收缩功能的改善方面考虑, 胺碘酮复律疗效优于心律平。     

Tencel纤维的原纤化及其织物风格加工技术

本文分析了Tencel纤维原纤化的形成机理 ,阐述了茸效应织物的加工技术与原纤化的控制。     

多异多重涤纶长丝原纤化现象初探

借助扫描电镜,观察多异多重复合涤纶长丝织物摩擦后纤维纵向截面形态,发现纤维出现原纤化现象,并对其产生原纤化的原因进行了初步探讨。结果表明,多异多重复合涤纶长丝由于其纺丝工艺的特点,形成皮芯结构和微原纤结构以及纤维的五叶形截面,使其在受到磨擦应力时,易发生原纤化现象。     

Adenosine A2A Receptors Are Upregulated in Peripheral Blood Mononuclear Cells from Atrial Fibrillation Patients

Atrial fibrillation (AF) is the most common form of cardiac arrhythmia seen in clinical practice. While some clinical parameters may predict the transition from paroxysmal to persistent AF, the molecular mechanisms behind the AF perpetuation are poorly understood. Thus, oxidative stress, calcium overload and inflammation, among others, are believed to be involved in AF-induced atrial remodelling. Interestingly, adenosine and its receptors have also been related to AF development and perpetuation. Here, we investigated the expression of adenosine A2A receptor (A2AR) both in right atrium biopsies and peripheral blood mononuclear cells (PBMCs) from non-dilated sinus rhythm (ndSR), dilated sinus rhythm (dSR) and AF patients. In addition, plasma adenosine content and adenosine deaminase (ADA) activity in these subjects were also determined. Our results revealed increased A2AR expression in the right atrium from AF patients, as previously described. Interestingly, increased levels of adenosine content and reduced ADA activity in plasma from AF patients were detected. An increase was observed when A2AR expression was assessed in PBMCs from AF subjects. Importantly, a positive correlation (p = 0.001) between A2AR expression in the right atrium and PBMCs was observed. Overall, these results highlight the importance of the A2AR in AF and suggest that the evaluation of this receptor in PBMCs may be potentially be useful in monitoring disease severity and the efficacy of pharmacological treatments in AF patients.     

Role of NADPH Oxidase and Xanthine Oxidase in Mediating Inducible VT/VF and Triggered Activity in a Canine Model of Myocardial Ischemia

Background: Ventricular tachycardia or fibrillation (VT/VF) of focal origin due to triggered activity (TA) from delayed afterdepolarizations (DADs) is reproducibly inducible after anterior coronary artery occlusion. Both VT/VF and TA can be blocked by reducing reactive oxygen species (ROS). We tested the hypothesis that inhibition of NADPH oxidase and xanthine oxidase would block VT/VF. Methods: 69 dogs received apocynin (APO), 4 mg/kg intraveneously (IV), oxypurinol (OXY), 4 mg/kg IV, or both APO and OXY (BOTH) agents, or saline 3 h after coronary occlusion. Endocardium from ischemic sites (3-D mapping) was sampled for Rac1 (GTP-binding protein in membrane NADPH oxidase) activation or standard microelectrode techniques. Results (mean ± SE, * p < 0.05): VT/VF originating from ischemic zones was blocked by APO in 6/10 *, OXY in 4/9 *, BOTH in 5/8 * or saline in 1/27; 11/16 VT/VFs blocked were focal. In isolated myocardium, TA was blocked by APO (10⁻⁶ M) or OXY (10⁻⁸ M). Rac1 levels in ischemic endocardium were decreased by APO or OXY. Conclusion: APO and OXY suppressed focal VT/VF due to DADs, but the combination of the drugs was not more effective than either alone. Both drugs inhibited ischemic Rac1 with inhibition by OXY suggesting ROS-induced ROS. The inability to totally prevent VT/VF suggests that other mechanisms also contribute to ischemic VT.     

The more effective treatment of atrial fibrillation applying the natural compounds; as NADPH oxidase and ion channel inhibitors

Atrial fibrillation (AF) is the most common cardiac arrhythmia that occurs because of several different risk factors, e.g., valvular heart disease, coronary artery disease, age ≥75 years, hypertension and diabetes mellitus. One key risk factor that results in AF, is oxidative stress. Evidence suggests that there is a correlation between oxidative processes and the genesis of AF. Oxidative stress occurs when the generation of reactive oxygen species (ROS) increase due to excessive activity of enzymes including NADPH oxidase (NOX) and xanthine oxidase; or its degradation decrease by dysfunctional antioxidant enzyme systems, such as superoxide dismutase (SOD), catalase and glutathione peroxidase (GPx). Afterwards, elevated ROS may shift ion channel activity to increase AF susceptibility.

The outbreak of AF continues to grow. Unfortunately, current treatment strategies may have limited efficacy or adverse effects. On the other hand, the inhibition of ROS formation and alteration of ion channel activity could be important therapeutic targets for prevention or treatments of AF. Additionally, many studies have been shown that several natural compounds have the ability to inhibit NADPH oxidases directly. This review focuses on natural compounds which specially inhibit NOX isoforms and have direct effects on ion channels, suggesting these compounds can be helpful in AF treatment.     

减少Lyocell纤维原纤化程度的化学方法研究

论述了减少Lyocell纤维湿加工原纤化程度的化学处理方法，包括碱处理、纤维素酶处理、树脂处理以及组合化学处理方法。通过对各种化学处理方法的防原纤化效果进行的比较，提出了防止Lyocell纤维原纤化的最佳处理工艺。     

两种离子液体溶剂干湿纺纤维素纤维的力学性能及孔结构研究

以离子液体氯化1-丁基-3-甲基咪唑([BMIM]Cl)和醋酸1-乙基-3-甲基咪唑([EMIM]Ac)为溶剂,通过干喷湿法纺丝工艺成功制备了高强型、高抗原纤化型和普通型3种典型的再生纤维素纤维,采用纤度-强伸度仪、湿摩擦和小角X射线散射法对再生纤维素纤维的力学性能、孔尺寸及其取向分布进行了表征,并探讨了其成型机制。结果表明:纺丝成型时的溶剂种类、原料聚合度、原液挤出胀大、拉伸应力、取向效应等因素决定了再生纤维素纤维的聚合度和取向度,进而促进具有不同力学性能、孔径及孔取向分布再生纤维素纤维的形成。     

心室纤颤和心动过速的小波非广度熵分析

为了对心动过速和心室纤颤进行准确而可靠的识别,提出了基于小波的多分辨率分析和熵相结合的分析方法.利用传统的Shannon熵信号分析方法获得的室颤和室速的识别率分别为96.4%和98.2%,而用非广度框架进行分析时获得的室颤和室速的识别率分别为100%和98.2%.表明作为检测室颤与室速的一个判据,Tsallis多分辨率熵(MRET)比Shannon多分辨率熵(MRE)具有更强的识别能力.该方法是一种稳定的、有效的特征提取方法,为其他非平稳生理信号的分析提供了新的手段.