Assessment of intracellular cytokines and regulatory cells in patients with autoimmune diseases and primary immunodeficiencies — Novel tool for diagnostics and patient follow-up

Serum and intracytoplasmic cytokines are mandatory in host defense against microbes, but also play a pivotal role in the pathogenesis of autoimmune diseases by initiating and perpetuating various cellular and humoral autoimmune processes.     

Influence of sustained submaximal clenching fatigue test on electromyographic activity and maximum voluntary bite forces in healthy subjects and patients with temporomandibular disorders

This study aimed to investigate whether the fatigue induced by sustained motor task in the jaw elevator muscles differed between healthy subjects and patients with temporomandibular disorder (TMD). Fifteen patients with TMD and thirteen age‐ and sex‐matched healthy controls performed a fatigue test consisting of sustained clenching contractions at 30% maximal voluntary clenching intensity until test failure (the criterion for terminating the fatigue test was when the biting force decreased by 10% or more from the target force consecutively for >3 s). The pre‐ and post‐maximal bite forces (MBFs) were measured. Surface electromyographic signals were recorded from the superficial masseter muscles and anterior temporal muscles bilaterally, and the median frequency at the beginning, middle and end of the fatigue test was calculated. The duration of the fatigue test was also quantified. Both pre‐ and post‐MBFs were lower in patients with TMD than in controls (P < 0·01). No significant difference was found in the percentage change in MBF between groups. The duration of the fatigue test in TMD patients was significantly shorter than that of the controls (P < 0·05). Our results suggest that, compared to healthy subjects, patients with TMD become more easily fatigued, but the electromyographic activation process during the fatigue test is similar between healthy subjects and patients with TMD. However, the mechanisms involved in this process remain unclear, and further research is warranted.     

The neuromuscular fatigue induced by repeated scrums generates instability that can be limited by appropriate recovery

The aim of this study was to evaluate the influence of the fatigue on the machine scrum pushing sagittal forces during repeated scrums and to determine the origin of the knee extensor fatigue. Twelve elite U23 rugby union front row players performed six 6-s scrums every 30 s against a dynamic scrum machine with passive or active recovery. The peak, average, and the standard deviation of the force were measured. A neuromuscular testing procedure of the knee extensors was carried out before and immediately after the repeated scrum protocol including maximal voluntary force, evoked force, and voluntary activation. The average and peak forces did not decrease after six scrums with passive recovery. The standard deviation of the force increased by 70.2 ± 42.7% (P < 0.001). Maximal voluntary/evoked force and voluntary activation decreased (respectively 25.1 ± 7.0%, 14.6 ± 5.5%, and 24 ± 9.9%; P < 0.001). The standard deviation of the force did not increase with active recovery and was associated with lower decrease of maximal voluntary/evoked force and voluntary activation (respectively 12.8 ± 7.9%, 4.9 ± 6.5%, and 7.6 ± 4.1%; all P < 0.01). As a conclusion repeated scrummaging induced an increased machine scrum pushing instability associated with central and peripheral fatigue of the knee extensors. Active recovery seems to limit all these manifestations of fatigue.     

Adjustments in the force–frequency relationship during passive and exercise‐induced hyperthermia

Introduction: We examined the extent to which fatiguing cycling exercise in the heat influences contractile function in modulating the force–frequency relationship. Methods: Before (∽37.0°C) and after (∽38.5°C) exercise (ExH) and passive (PaH) hyperthermia, an 8‐s train of stimulation at 10, 20, 50, and 100 Hz (2 s per frequency) and a potentiated twitch were evoked on the relaxed knee extensors using percutaneous stimulation. Results: ExH and PaH produced a decrease in the 20:50 Hz force ratio, indicative of low‐frequency fatigue (P < 0.01). This adjustment was more pronounced after ExH than PaH (P < 0.01). A rightward displacement in the force–frequency relationship occurred after ExH and PaH (P < 0.05) and was exacerbated by ExH (P < 0.05). Peak twitch force also decreased after ExH (P < 0.05). Conclusions: ExH reduces force summation due to development of skeletal muscle fatigue, exacerbating the shift in force–frequency to the right relative to PaH. Muscle Nerve 50 : 822–829, 2014     

Personality and Self-Motivation during Biochemical Fatigue

Abstract

The present study was conducted to determine whether females exhibiting the Type A behavior pattern would exert greater effort and work to higher levels of physiological fatigue in a self-motivated ergometer test. Twenty female subjects, half of them Type A and the other half Type B, were administered an incremental ergometer test to determine their peak oxygen consumption value. On the first experimental session no experimenter encouragement was given to the subjects. Consequently the test measured physical motivation levels. During a second laboratory session, each subject was continuously encouraged by the experimenter to maintain exercising until she was truly incapable of further work. The highest rate of oxygen extraction during this latter session was considered the subject's maximum oxygen consumption (i.e., VO₂ max). Type A and B subjects were compared in the nonmotivated testing session (experimental session 1) to their “true” individual capacities (maximum oxygen consumption demonstrated in experimental session 2). ANOVAs indicated no significant differences in self-initiated competitive behavior during a physical stressor.     

不同预后慢性疲劳综合征患者精神情志因素差别分析

目的:研究CFS患者精神情志因素与预后的关系。方法:运用SCL90量表及FS-14量表对120例未干预治疗CFS患者进行测评并进行3个月随访,分析精神情志因素与患者预后的关系。结果:未干预治疗CFS患者中有70.83%的患者症状未见好转,好转组评分与未好转组SCL-90评分有统计学差异(P<0.05)的因子分有:躯体化、敌对、抑郁、焦虑及总分。结论:(1)未干预治疗CFS患者预后不佳,高达70%以上的患者在未经适当治疗的情况下持续存在各种精神情志症状。(2)当CFS患者存在明显自觉躯体症状、敌对、强迫、抑郁、焦虑等负面情绪时其预后多不佳。     

大学生电子产品使用与视疲劳发生的相关性分析

目的　调查大学生视疲劳的患病率及其与电子设备使用之间的关系。方法　2016至2017学年第二学期向全国29个省份（除台湾、青海、西藏、宁夏、新疆）127所大学学生随机分发6000份问卷，问卷内容包含电子设备的依赖情况，电子设备在寝室、家中、交通工具上使用情况以及视疲劳患病情况。使用Logistic回归分析视疲劳危险因素。结果　总计回收有效问卷4848份，其中男2259份，女2589份。结果显示，受调查的大学生人群中视疲劳的患病率为53.5%，女性高于男性，其中33.8%的学生表示已对电子设备产生依赖，在桌前、床上、交通工具上使用电子设备的人分别达到了91.3%、87.6%和74.8%。在使用时间上，中国大学生每天使用手机、平板、电脑等4.0 h以上的达38.3%，每天在床上使用电子设备超过1.0 h的达29.7%，在交通工具上使用≥0.5 h的达49.1%。单因素Logistic回归分析认为性别、电子设备的依赖情况、电子设备在寝室、家中、交通工具上的使用情况等与视疲劳的发生均具有相关性。结论　大学生视疲劳的患病率较高，性别、电子设备的依赖情况、电子设备在不同场景上的使用情况等因素对大学生视疲劳的患病率均有一定的影响。