Stochastically-modulated stimulation to slow down muscle fatigue at stimulated sites in paraplegics using functional electrical stimulation for leg extension

Abstract

This short communication is a preliminary report on a study concerning slowing down the rate of muscle fatigue when FES (Functional Electrical Stimulation) is applied for standing and walking by complete (traumatic) thoracic-level paraplegics. It is shown that randomly modulating the inter-pulse interval between FES pulses (which serve to trigger action potentials in the peripheral nerves concerned) re~lJlts in a significantly lower rate ofmuscle fatigue, as tested in a series ofleg extensions, when FES was applied at the quadriceps. Specifically, we report that the best results (longest durations of leg extension prior to onset of muscle-fatigue) were achieved with a ± 5 msec uniformly-distributed (pseudo-) white-noise modulation at a 42 msec inter-pulse interval (24 pulses per sec). These resulted in an average increase in duration of leg extension ofapproximately 37% in this pilot study, as compared with unmodulated (fixed-rate) trains ofFES pulses. This significant increase, even in a very preliminary study appears to merit careful further examination, since it may allow a possibly significant increase in standing duration and in walking range of paraplegics using FES for ambulation. [Neural Res 2000; 22: 703-704]     

Oncolytic viruses and DNA-repair machinery: overcoming chemoresistance of gliomas

The current standard of care for malignant gliomas is surgical resection and radiotherapy followed by extended adjuvant treatment with the alkylating agent temozolomide. Temozolomide causes DNA damage, which induces cell death. Through changes in the DNA-repair machinery, glioma cells develop resistance to temozolomide, compromising the therapeutic effect of the drug. Oncolytic viruses, such as herpes simplex viruses and adenoviruses, are being introduced into clinical trials as a new treatment for this malignancy. Biological studies have revealed that these viruses use mechanisms to either inactivate (adenovirus) or take advantage of (herpes simplex virus) the cellular DNA-repair machinery to achieve productive replication. Adenoviruses express proteins from the early genes to either downregulate the damage-repair enzyme, O⁶-methylguanine-DNA methyltransferase, or degrade poly (ADP-ribose) polymerase or the Mre11-Rad50-NBS1 complex, which detects DNA strand breaks. Temozolomide enhances herpes simplex virus oncolysis by upregulating the DNA repair-related genes growth arrest DNA damage 34 and ribonucleotide reductase. The interactions between viruses and the DNA-repair machinery suggest that a combined temozolomide and viral therapy will overcome the limitations of a single therapy by diminishing chemoresistance or enhancing oncolysis. This hypothesis has been supported by promising findings from preclinical and clinical studies.     

3D-echo in preoperative assessment of aortic cusps effective height

Effective height,which represents the height difference between the central free margins and the aortic insertion lines can be easily determined by 2-D echocardiography and allows for identification of prolapse in the native cusps and assessment of prolapse correction after valve repair.Nonetheless,it allows to see only two of three aortic valve(AV)coaptation planes and this may lead to misunderstanding of the underlying pathophysiological mechanism for aortic regurgitation and hence in unsuccessful repair.In contrast,3D transoesophageal echocardiography and multiple plane reconstruction lets visualize all the three coaptation planes between the AV cusps and it represents an invaluable tool in the assessment of aortic valve geometry.It is highly recommendable before AV repair to accurately study the complex three dimensional cusps anatomy and their geometric interrelation with aortic root.     

"对位对线"补片固定法在腹腔镜造口旁疝Sugarbaker修补术中的应用

目的腹腔镜下Sugarbaker修补手术是造口旁疝的主要手术方式，补片固定是手术的关键技术环节，本研究介绍一种新式补片固定方法，并探讨其在临床上的应用效果。 方法回顾性分析2017年6月至2019年6月在中山大学附属第六医院住院的66例造口旁疝患者临床资料，患者均行腹腔镜造口旁疝修补手术（Sugarbaker术式），根据补片固定方式的不同分为试验组（41例，采用"对位对线"补片固定法）和对照组（25例，采用传统疝钉双圈补片固定方法）。比较两组患者相关指标和治疗效果。 结果两组患者性别、年龄、体质指数、病程以及造口旁疝分型比较，差异均无统计学意义。试验组补片固定时间短于对照组[（32.6±9.0）min vs（38.7±11.0）min，P<0.05]，两组在疝钉固定数量、血清肿、补片感染、术后住院时间指标方面，差异无统计学意义。试验组和对照组的平均随访时间差异无统计学意义[（37.6±14.8）个月vs（38.8±15.2）个月，P=0.687]，试验组的造口旁疝复发率低于对照组（2.4% vs 20.0%，P<0.05），而两组术后慢性疼痛发生率差异无统计学意义（24.2% vs 24.0%，P=0.971）。 结论在腹腔镜造口旁疝Sugarbaker修补术中应用"对位对线"补片固定法，可以缩短补片固定时间并减少术后复发，值得临床上推广使用。