运动疲劳对大鼠十二指肠电活动的影响

本文报道了大鼠十二指肠电活动在运动疲劳前后的数值。结果表明：在运动疲劳后，快波、慢波振幅明显增加，而其频率却减少；Ⅰ相缩短，Ⅱ相延长，Ⅲ相、Ⅳ相及ＩＤＭＥＣ周期无显著变化；并在运动疲劳后９．７±２．４ｍｉｎ内出现不规律的食后型的电活动。这些改变可了解运动疲劳对消化系统的影响。     

安吉复口服液的耐缺氧,耐低温和抗疲劳作用

采用缺氧、寒冷和负重游泳等方法,观察了安吉复口服液(0.025、0.1和0.4mg·kg~(-1),ig,qd×14d)对小鼠的耐缺氧、耐低温及抗疲劳作用.结果表明,安吉复口服液0.1、0.4mg·kg~(-1)可延长KCN中毒小鼠的存活时间及延长小鼠在寒冷环境中存活时间,而0.4mg·kg~(-1)可延长常压缺氧条件下小鼠存活时间及延长小鼠负重游泳时间.     

胫骨前肌疲劳时比目鱼肌诱发肌电图H波的变化及其机制探讨

为了解主动肌疲劳时拮抗肌脊髓运动神经元兴奋性变化的规律 ,本研究采用踝关节背屈运动形式 ,对胫骨前肌 (主动肌 )疲劳状态下的比目鱼肌 (拮抗肌 )诱发肌电图H波成分进行了观察。并以压迫阻断胫骨前肌Ⅰa类神经纤维传导的方法 ,对比目鱼肌H波变化机制进行了分析探讨。结果发现 :(1)胫骨前肌疲劳后 ,比目鱼肌H波明显受到抑制 ,与安静时比较呈非常显著性差异 ;(2 )胫骨前肌Ⅰa类神经纤维传导被阻断后 ,比目鱼肌H波的抑制现象没有解除。表明 ,胫骨前肌疲劳时比目鱼肌H波被抑制的原因 ,可能是由于主动肌内的代谢产物激活了Ⅲ·Ⅳ类神经纤维的感受器 ,Ⅲ·Ⅳ类神经纤维的传入冲动增加 ,使Ⅰa抑制性中间神经元被激活 ,导致拮抗肌脊髓运动神经元的兴奋性受到了抑制     

Advances in processing of surface myoelectric signals: Part 1

During sustained voluntary or electrically elicted muscle contractions the surface myoelectric signal is nonstationary and it undergoes progressive changes reflecting the modifications of the motor unit action potentials and their propagation velocity. In particular, during sustained electrical stimulation, the evoked signals show progressive amplitude, time scaling and shape modification. The quantitative evaluation of these changes is important for non-invasive muscle characterisation and may be performed in either the time or frequency domain using parametric and nonparametric spectral analysis as well as alternative methodologies. The paper introduces the detection techniques, reviews and compares the methods of spectral estimation based on FFT and autoregressive models, and discusses their applications and limitations in extracting information from the surface myoelectric signal with particular regard to myoelectric manifestations of localised muscle fatigue during sustained contractions.     

Levodopa improves physical fatigue in Parkinson's disease: a double-blind, placebo-controlled, crossover study.

We quantitatively investigated the effect of carbidopa/levodopa (25/100) on physical fatigue during finger tapping and force generation in a double-blind, placebo-controlled crossover study. Parkinson's disease (PD) subjects were randomly assigned to carbidopa/levodopa or placebo for Visit 1 or 2 and participated in the following two studies: (1) Finger tapping. Twenty-five PD patients used their index fingers to strike two keys 20 cm apart on a musical instrument digital interface (MIDI) keyboard. The slopes of the regression line of dwell time and movement time were used to assess the rate of fatigue development. (2) Force generation. Twelve PD patients contracted the wrist extensors maximally to obtain a baseline maximum voluntary contraction (BMVC) force. Then they repetitively contracted the wrist extensors at 50% of the BMVC for 7 seconds and rested for 3 seconds. An interval maximum voluntary contraction (IMVC) was measured every three repetitions. Fatigue was defined as an IMVC of less than 60% of the BMVC. The slope of the regression line of IMVC was used to assess the rate of force decline. These two studies were repeated 1 hour after carbidopa/levodopa (25/100) or placebo. Subjects filled out the Multidimensional Fatigue Inventory (MFI) at the beginning of the first visit. Results showed that the slope of dwell time decreased with levodopa but not with placebo (P = 0.004). The rate of force decline also decreased with levodopa but not with placebo (P = 0.01). The subscores in the dimension of physical fatigue in the MFI did not correlate with the rate changes in dwell time or the rate changes in force decline. We concluded that (1) levodopa improves physical fatigue in finger tapping and force generation, (2) physical fatigue in Parkinson's disease is at least partially related to dopamine deficiency, and (3) the MFI measures different aspects of physical fatigue compared with those measured by finger tapping and force generation.     

Predicted and Measured Muscle Forces after Recoveries of Differing Durations Following Fatigue in Functional Electrical Stimulation

Abstract: Using ³¹P nuclear magnetic resonance (NMR) spectroscopy, the bioenergetics of paralyzed muscles activated by functional electrical stimulation (FES) were studied in vivo during fatigue and recovery on paraplegic subjects. During the activation phase of the muscle, the muscle force was also monitored. The phosphorus metabolites were found to vary systematically during fatigue and to recover slowly to their rest state values after cessation of FES. During fatigue, a good correlation was found between the decaying force and each of the profiles of phos-phocreatine, inorganic phosphorus, and intracellular pH. A musculotendon 5 element model was proposed for the activated muscle to predict its force generation capacity. A fatigue recovery function, based on the metabolic profiles, was introduced into the model. This model allowed us to predict the force expected to be developed as a function of the time after recovery of given time durations. Validation experimental measurements of force were carried out and included recurrent fatigue tests, both in the initially un-fatigued state and at various times in the postfatigue stage of the muscle. Comparison of the predicted and measured forces indicated satisfactory agreement of the results. The developed model of muscle dynamics should help to design a strategy for reducing muscle fatigue under FES.     

视觉近点测定修布和验布作业视疲劳的初步探讨

应用视觉近点测定评价纺织厂不同作业工人的视疲劳。检查了32名修布工人和38名验布工人。同一工厂的33名保育员作对照组。结果表明:视觉近点的测定指标比调查受试者主诉的眼视觉症状更为敏感。修布和验布组在工作后,作业者的视觉近点比上班前明显变远,但时照蛆工作前后无明显变化。三组视觉近点比较,发现修布和验布组视觉近点的变化。提示由修布和验布作业引起的视觉疲劳,可以通过测定视觉近点来进行评价。     

山东产四种菟丝子免疫增强作用的比较研究

目的 比较山东产四种菟丝子对小鼠免疫功能、抗疲劳、耐缺氧等方面的作用。方法 选用昆明种小鼠，用山东产四种菟丝子的水、醇提取物灌胃，观察小鼠腹腔巨噬细胞吞噬功能、免疫器官重量的变化、游泳实验和耐缺氧等指标。结果 山东产四种菟丝子均可增加小鼠吞噬百分率，使幼龄小鼠的胸腺和脾脏增重，并可显著延长小鼠的游泳及缺氧存活时间。其中以菟丝子和南方菟丝子的作用较好，水提取物的作用优于醇提取物。结论 山东产四种菟丝子具有增强机体免疫功能、抗疲劳、耐缺氧作用。菟丝子中的多糖是其提高机体免疫力，增强体质的有效物质之一。