Comparative study of wavelet denoising in myoelectric control applications

Here, the wavelet analysis has been investigated to improve the quality of myoelectric signal before use in prosthetic design. Effective Surface Electromyogram (SEMG) signals were estimated by first decomposing the obtained signal using wavelet transform and then analysing the decomposed coefficients by threshold methods. With the appropriate choice of wavelet, it is possible to reduce interference noise effectively in the SEMG signal. However, the most effective wavelet for SEMG denoising is chosen by calculating the root mean square value and signal power values. The combined results of root mean square value and signal power shows that wavelet db4 performs the best denoising among the wavelets. Furthermore, time domain and frequency domain methods were applied for SEMG signal analysis to investigate the effect of muscle-force contraction on the signal. It was found that, during sustained contractions, the mean frequency (MNF) and median frequency (MDF) increase as muscle force levels increase.     

形态心电图标准在鉴别心室流出道室性心律失常中的价值

目的探讨形态心电图标准在心室流出道（VOT）室性心律失常（VA）中的鉴别价值。方法回顾性分析155例成功行射频导管消融治疗（以下简称消融治疗），并经三维标测或X线影像证实起源于左心流出道（LVOT）室性期前收缩/室性心动过速（PVC/VT）的心电图资料进行观察（观察组），使用系统抽样法选取同期成功行消融治疗的155例右心室流出道（RVOT）起源的PVC/VT进行对照（对照组），再根据起源的位置不同将观察组分为3个亚组：左冠窦（LCS）组、右冠窦（RCS）组、左冠窦下（ILCS）组。观察各组V1、V2导联R波振幅及时限比值、胸导联移行指数、V2导联移行比、胸导联QRS波的移行情况，分析其对LVOT和RVOT及各亚组的PVC/VT鉴别价值，并计算各项指标的灵敏度、特异度、阳性预测值和阴性预测值。结果LVOT和RVOT的PVC/VT的V1、V2导联R波振幅以及R波时限比值及V2导联移行比、胸导联移行、胸前导联移行指数均有较为明显的差异。LVOT亚组分析显示：（1）符合胸导联移行指数＜0，在LCS组、ILCS组及RCS组分别为92.39%（85/92）、90.91%（30/33）、90.00%（27/30）。（2）符合V1导联的R波振幅比值≥0.3及时限比值≥0.5，在上述3组分别89.13%（82/92）、93.94%（31/33）、76.67%（23/30）。（3）符合V2导联的R波振幅比值≥0.3及时限比值≥0.5，在上述3组分别为88.04%（81/92）、93.94%（31/33）、90.00%（27/30）。（4）V2导联移行比＞0.6，在上述3组分别为89.13%（82/92）、93.94%（31/33）、83.33%（25/30）。（5）PVC的胸导联移行在ILCS组有93.39%（31/33）在V1导联之前，其余亚组均在V1导联之后。（6）I导联QRS波形态LCS组及ILCS组以负向波为主呈rs/rS型，分别为78.26%（72/92）及81.81%（27/33），RCS组以正向波为主呈R或r型76.67%（23/30）。结论在VOTPVC/VT的形态心电图鉴别标准中，胸导联移行指数对于鉴别LVOT与RVOT起源，具有较高的灵敏度、特异度、阳性预测值及阴性预测值，应被优先选用。     

囊袋收缩综合征的手术治疗

目的探讨白内障超声乳化术后囊袋收缩综合征的手术治疗效果。方法对12例（12只眼）白内障超声乳化术后并发囊袋收缩综合征进行囊袋松解术，观察术后视力及并发症情况。结果12只眼术后视力均有提高，10只眼视力〉10．4，2只眼视力0．1～0．3，无明显并发症发生。结论囊袋松解术是治疗重度囊袋收缩综合征的有效方法。     

Intermedin inhibits norepinephrine-induced contraction of rat seminal vesicle

ObjectiveTo study the effect of inter medin(IMD) on smooth muscle of rat seminal vesicles including the specific receptors and the signal pathways involved.MethodsThe contraction of the seminal vesicle in response to norepinephrine (NE) and ADM2/IMD was studied by the organ bath method. The effects of antagonists for calcitonin gene related peptide (CGRP), adrenomedullin (ADM) and IMD receptors, and inhibitors of nitric oxide synthase, [L-NG-Nitroarginine Methyl Ester, L-NAME) and cAMP-dependent protein kinase (PKA), KT5720] were also investigated. The first overshoot, amplitude, frequency and basal tone were measured.ResultsThere is no significant effect of IMD on the initial overshoot, frequency and the basal tone in the seminal vesicle contraction. Only the amplitude of the contraction induced by NE was inhibited by IMD. The IMD inhibitory actions on amplitude were completely blocked by hADM22-52 and L-NAME, but not by hCGRP8-37 or KT5720. Furthermore, the action was diminished by IMD17-47.ConclusionThe results demonstrated that the inhibitory action of IMD on NE-induced seminal vesicle contraction was mediated via the ADM receptor(s) and the nitric oxide production pathway, partially by the IMD receptor, but not by the CGRP receptor and the cAMP-PKA pathway.     

Fetal Skin Organ Culture

The fetal response to cutaneous injury has been investigated in a variety of models; most have studied the differences between fetal and adult healing mechanisms in vivo and in cell culture. Further disclosure of the cellular and biochemical events requires a model that can be manipulated to study single factors influencing fetal tissue repair without the complex interactions that occur in vivo, but in a system that more closely approximates normal skin than cell culture models. This paper presents a method for the organ culture of fetal skin and its advantages as a model to help elucidate fetal healing mechanisms. Skin sections (1 × 1 cm) excised from the backs of fetuses of New Zealand white rabbits on day 27 gestation (term = 31 days) were placed eccentrically in 65-mm culture dishes and fed daily with 2.5 mL of DMEM containing 10% fetal calf serum, antibiotics, and 10 mM ascorbic acid. A separate group, treated similarly, received 4-mm punch wounds to assess the in vitro response to wounding. Thespecimens were incubated at 37° Cin humidified room air on a rocker platform to provide alternate exposure of the skin to air and medium. Gross observation at 3 weeks showed cells extending into the central wound, indicating that viable cells were proliferating and/or migrating from the tissue. Skin was examined histologically and was viable over the 3-week period studied. Organ culture, by maintaining tissue in the natural extracellular matrix, allows cell-to-cell contact and communication to be maintained while allowing controlled environmental manipulation. In addition, the procedure is reproducible and assessment of tissue viability can be determined easily using histology. These advantages make fetal skin organ culture a valuable adjunct in the study of fetal skin and its response to wounding.     

Modeling heart failure in animal models for novel drug discovery and development

Introduction: When investigating drugs that treat heart diseases, it is critical when choosing an animal model for the said model to produce data that is translatable to the human patient population, while keeping in mind the principles of reduction, refinement, and replacement of the animal model in the research.

Areas covered: In this review, the authors focus on mammalian models developed to study the impact of drug treatments on human heart failure. Furthermore, the authors address human patient variability and animal model invariability as well as the considerations that need to be made regarding choice of species. Finally, the authors discuss some of the most common models for the two most prominent human heart failure etiologies; increased load on the heart and myocardial ischemia.

Expert opinion: In the authors’ opinion, the data generated by drug studies is often heavily impacted by the choice of species and the physiologically relevant conditions under which the data are collected. Approaches that use multiple models and are not restricted to small rodents but involve some verification on larger mammals or on human myocardium, are needed to advance drug discovery for the very large patient population that suffers from heart failure.     

Effect of single bout downhill running on the serum irisin concentrations in rats

Abstract

This study aimed to characterize the effect of different running modes on serum irisin concentrations in rats. A total of 18, 10-week-old rats were divided into three groups; control group, 16° uphill running group (concentric exercise; CON) and, ?16° downhill running group (eccentric exercise; ECC). The running group’s rats ran on the inclined treadmill at 16?m/min, for a total of 90?min. Blood was drawn from the rats, 48?h after running, after which the rats were anesthetized. The serum concentrations of irisin were measured using enzyme-linked immunosorbent assays. Vastus intermedius was collected for immunohistochemical analysis. After multiple comparisons, the ECC showed a significantly high serum irisin concentration (ECC: 28.42?±?6.31?ng/ml, CON: 21.27?±?3.03?ng/ml) and a larger irisin antibody reactive cross-sectional area in vastus intermedius compared to the CON (p?<?0.05). This is the first study to reveal that single bout downhill running increases serum irisin concentrations in rats.     

Empagliflozin restores chronic kidney disease–induced impairment of endothelial regulation of cardiomyocyte relaxation and contraction

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扶正利胆汤对贲门癌术后胆囊收缩障碍的临床疗效观察

目的 研究扶正利胆汤对贲门癌术后胆囊收缩障碍的临床治疗作用及其机制探讨.方法 选择120例贲门癌术后患者,随机分为试验组60例和对照组60例;试验组患者,在术后第10天开始口服扶正利胆汤,连服20天;对照组患者,在术后第10天口服等体积的水,连服20天;在实验治疗期间,对上述两组患者均进行常规抗炎、补液等治疗.所有患者分别于术前3天、术后30天对胆囊进行超声波指标测定,测定条件是空腹、服用脂餐0.5小时后、服用脂餐1小时后,应用超声波测定胆囊最大纵切面积、长径、短径,计算胆囊超声容积、排空率指标,并在术前3天、术后30天测定空腹血清胆囊收缩素浓度.比较两组患者手术前后胆囊的容积、排空、排空率及空腹血清胆囊收缩素浓度.结果 1）两组患者手术前后胆囊收缩功能比较：对照组患者术后胆囊容积较术前明显增大（P＜0.05）,治疗组患者术后胆囊容积较术前没有显著性改变;术前治疗组和对照组患者胆囊容积无显著差别（P＞0.05）;术后试验组胆囊容积比对照组患者的胆囊容积明显缩小,两组比较具有显著性差异（P＜0.05）.2）两组患者手术前后空腹血清胆囊收缩素（CCK）浓度比较：术前两组CCK浓度无明显差别（P＞0.05）;术后对照组患者CCK浓度较术前明显下降（P＜0.05）,治疗组患者术后CCK浓度较术前无明显改变（P＞0.05）,术后试验组患者较对照组血清CCK浓度明显升高,两组比较有显著性差异（P＜0.05）.结论 贲门癌术后出现胆囊排空障碍,术后胆囊容积与术前相比明显增大.扶正利胆汤可以提高血清CCK浓度,改善术后胆囊容积,对于贲门癌术后的胆囊收缩障碍有一定的治疗作用.