低氧运动干预对大鼠心肌细胞自噬作用的探讨

目的:探讨常压低氧(13.6%氧含量)运动对大鼠心肌核转录因子NF-κB、Cyt c和自噬相关基因Beclin1的影响,为运动与低氧适应机制的研究和高原训练方案的制定提供理论依据。方法:采用酶联免疫吸附技术(ELISA)分别测大鼠心肌NF-κB、Cyt c和Beclin1的含量。结果:通过运动训练、低氧适应或者是低氧运动适应,都能使NF-κB和Beclin1不同程度升高,其中以HC和HiLo较为显著,Cyt c变化不明显,提示运动训练、低氧适应或者低氧运动适应都能诱导自噬的发生。结论:自噬相关基因Beclin1在低氧训练中产生的低氧适应机制可能是低氧刺激后细胞内产生ROS,ROS激活了NF-κB信号通路,使得Beclinl与NF-κB活性增高;通过长期的运动与低氧适应,可能ROS降低有效抑制NF-κB信号通路,使Beclinl和NF-κB产生了适应性变化,Cyt c从线粒体释放较少,提示细胞凋亡率减少,从而保护心肌细胞的作用。     

运动训练对自发性高血压大鼠心肌细胞凋亡蛋白表达的影响

目的:研究运动训练对SHR心肌细胞中HSP-72、Bcl-2和蛋白激酶β(PKB)、Bax、糖原合成激酶-3(GSK-3)的影响,以探讨其对运动引起心肌细胞凋亡的作用。方法:以SHR大鼠中等强度训练为实验模型,采用Western bloting技术检测了大鼠心肌细胞中调控蛋白HSP-72、Bcl-2和蛋白激酶β(PKB)、Bax、糖原合成激酶-3(GSK-3)的表达。结果:长期中等强度训练可以提高心肌细胞中抑凋亡蛋白HSP-72、Bcl-2和蛋白激酶β(PKB)的表达,凋亡蛋白Bax、糖原合成激酶-3(GSK-3)表达显著降低,Bcl-2/Bax的表达没有显著变化,从而抑制心肌细胞的凋亡。结论:心肌细胞中HSP-72、Bcl-2和蛋白激酶β(PKB)、Bax、糖原合成激酶-3(GSK-3),Bcl-2/Bax在运动后的不同表达对心肌细胞凋亡的发生有明显的抑制作用。     

自主运动抑制tau蛋白过度磷酸化改善学习记忆的分子机制

目的探讨自主运动调节tau蛋白激酶和tau蛋白磷酸酶的基因表达,抑制APP/PS1转基因小鼠海马tau蛋白过度磷酸化,进而改善学习记忆能力的分子机制。方法C57系APP/PS1转基因小鼠随机分为运动组(TE)与对照组(TC);C57系野生小鼠亦随机分为运动组(E)与对照组(C)。其中,TE组和E组小鼠从3月龄开始,给予16周的跑轮运动装置,TC组和C组小鼠不施加运动干预,作为相应对照组。Morris水迷宫实验检测APP/PS1转基因小鼠的空间学习记忆能力,Western Blot实验检测海马磷酸化tau蛋白(P-tau)水平,RT-PCR实验检测海马tau蛋白及tau蛋白激酶GSK-3β和CDK-5,tau蛋白磷酸酶PP2A和PP1 mRNA表达。结果(1)与TC组相比,TE组小鼠Morris水迷宫游泳潜伏期显著性降低(P<0.05),平台象限的游泳时间百分比显著性增加(P<0.05),穿越原平台位置的次数极显著性增加(P<0.01);(2)与TC组相比,TE组小鼠海马总tau蛋白mRNA表达显著下调(P<0.05),Ser202位点和Thr181位点P-tau蛋白表达均显著性下调(P<0.05);(3)与TC组相比,TE组小鼠海马tau蛋白磷酸化激酶GSK-3β(P<0.01)和CDK-5(P<0.05)mRNA表达显著性下调,tau蛋白磷酸酶PP2A(P<0.01)和PP1(P<0.01)mRNA表达极显著性下调。结论16周自主运动通过下调tau蛋白激酶表达、上调tau蛋白磷酸酶表达,抑制APP/PS1转基因小鼠海马tau蛋白的过度磷酸化,进而促进海马神经细胞功能,改善转基因小鼠学习记忆。说明自主运动可通过调节脑的分子生物学机制,促进认知功能的改善和提升,预防和缓解阿尔茨海默病。     

局部文本特征选取算法的比较和改进研究

本文通过实验比较了互信息、χ2统计算法和优势率三种算法在用于局部文本特征选取时对文本分类性能的影响.实验结果显示,在应用于局部特征选择的情况下,文本特征选取算法仍然可以将特征空间的维度降低90%以上,而不降低文本分类的性能.同时,我们发现在应用于局部文本特征选取时,优势率算法的性能不如互信息和χ2统计算法.另外,对于K最近邻分类算法,随着K值的增大,文本分类的查准率在增加,而查全率在降低.最后,本文详细分析了造成这三种算法性能差异的原因,并提出了一种改进算法,来提高优势率算法应用于局部文本特征选取时的性能.     

对足球训练中运用Yo-Yo测试的原理、作用和方法的研究

作为一种体能测试方法和手段，Yo—Yo目前已被中国足协作为对国内职业足球俱乐部的体能测试的内容。使用文献资料，观察、实验等方法，对Yo-Yo测试的原理及其作用方法进行了探讨和研究，为Yo-Yo测试提供理论和实践上的依据。     

Activity profile of top-class association football referees in relation to performance in selected physical tests

Abstract

The aims of the present study were (1) to analyse the physical demands of top-class referees and (2) to compare their official FIFA fitness test results with physical performance during a match. The work rate profiles of 11 international referees were assessed during 12 competitive matches at the 2003 FIFA Under-17 World Cup and then analysed using a bi-dimensional photogrammetric video analysis system based on direct lineal transformation (DLT) algorithms. In the first 15 min of matches, the referees were more active, performing more high-intensity exercise (P < 0.01) than in the first 15 min of the second half. During the second half of matches, the referees covered a shorter distance (P < 0.01), spent more time standing still (P < 0.05), and covered less ground cruising (P < 0.05), sprinting (P < 0.05), and moving backwards (P < 0.001) than in the first half. Also in the second 45 min, the distance of referees from infringements increased (P < 0.05) in the left attacking zone of the filed. There was also a decrease (P < 0.05) in performance in the period following the most high-intensity activity, compared with the mean for the 90 min. Time spent performing high-intensity activities during a match was not related to performance in the 12-min run (r ² = 0.30; P < 0.05), the 200-m sprint (r ² = 0.05; P < 0.05), or the 50-m sprint (r ² = 0.001; P < 0.05). The results of this study show that: (1) top-class referees experienced fatigue at different stages of the match, and (2) the typical field tests used by FIFA (two 50-m and 200-m sprints, followed by a 12-min run) are not correlated with match activities.     

Heart rate prescribed walking training improves cardiorespiratory fitness but not glycaemic control in people with type 2 diabetes

Abstract

In this study, we examined the effects of a supervised, heart rate intensity prescribed walking training programme on cardiorespiratory fitness and glycaemic control in people with type 2 diabetes mellitus. After receiving local ethics approval, 27 individuals (21 males, 6 females) with type 2 diabetes were randomly assigned to an experimental (“walking”) or control group. Participants completed a Balke-Ware test to determine peak heart rate, peak oxygen consumption ([Vdot]O_2peak), and peak gradient. The walking group then completed a 7-week (four sessions a week) supervised, heart rate prescribed walking training programme, whereas the control group continued daily life. After training, participants completed another Balke-Ware test. Fasting blood glucose and glycosylated haemoglobin were measured at rest. The results showed that walking training elicited 80% (s = 2) of peak heart rate and a rating of perceived exertion of 11 (s = 1). Peak heart rate and [Vdot]O_2peak were higher in the walking than in the control group after training (P < 0.05). Based on the peak gradient before training, the respiratory exchange ratio was significantly lower (P < 0.05) and there was a strong trend for [Vdot]O₂ (P = 0.09) and heart rate (P = 0.09) to be lower after training at the same gradient in the walking compared with the control group. These improvements increased walking peak gradient by 5 min (s = 4 min) compared with the control (P < 0.05). There was no change in fasting blood glucose or glycosylated haemoglobin after training. Despite no change in glycaemic control, heart rate prescribed walking improved peak and sub-maximal cardiorespiratory responses. The beneficial adaptations support the use of heart rate monitoring during walking in people with type 2 diabetes mellitus.     

Alterations in Strength and Maximal Oxygen Uptake Consequent to Nautilus Circuit Weight Training

Abstract

The purpose of this study was to determine the effects of a Nautilus circuit weight training program on muscular strength and maximal oxygen uptake ([Vdot]O ₂ max) by comparing these effects to those produced by adhering to either a free weight (FW) strength training program or a running (R) program. Male college students who voluntarily enrolled in either a FW training class (n = 11), a Nautilus (N) circuit weight training class (n= 12), or a R conditioning class (n= 13) were subjects for this investigation. All groups participated in their respective programs 3 days per week for 10 weeks. Strength was assessed using a Cybex II isokinetic dynamometer set at an angular velocity of 60° · s ^?1 and a damping of 2. The FW group served as the control group for the assessment of [Vdot]O ₂ max changes, while the R group served as controls for the assessment of strength differences. ANCOVA revealed that the N and R groups experienced significant (p < .01) increases in [Vdot]O ₂ max expressed in L · min ^?1 (10.9 and 11.4%), ml · kg ^?1 · min ^?1 (10.8 and 11.7%), and ml · kgLBW ^?1 · min ^?1 (7.1 and 7.5%) when compared to the FW group. There were no significant differences between the N and R groups. There were no significant differences among groups in final peak torque values (after covariance), and torque at the beginning and end of the range of motion for the knee extensors, knee flexors, elbow extensors, and elbow flexors. In general, isokinetic strength values elicited by the N group compared favorably to those generated by the FW group. It was concluded that for a training period of short duration, Nautilus circuit weight training appears to be an equally effective alternative to standard free weight (strength) and aerobic (endurance) training programs for untrained individuals.     

运动训练对大鼠睾丸组织NOS、Bax、Bcl-2表达的影响

目的探讨不同强度运动训练对大鼠睾丸组织NOS和细胞凋亡表达的影响及其与睾酮水平相关性。方法24只健康雄性大鼠,随机分为对照组,有氧运动组,大强度运动组,每组8只。采用递增强度方式进行跑台运动,训练过程共持续8周。测定大鼠睾丸组织NOS表达、细胞凋亡及血睾酮的含量。结果与安静对照组相比,有氧训练组大鼠睾丸组织NOS表达、细胞凋亡及血睾酮含量无显著性差异。而疲劳训练组大鼠睾丸组织eNOS和Bax表达显著升高(P<0.05),nNOSi、NOS和Bcl-2表达及血睾酮含量显著降低(P<0.05)。结论有氧训练大鼠睾丸组织NOS表达、细胞凋亡对血睾酮水平影响不显著;大强度疲劳训练大鼠睾丸组织NO过量表达,细胞凋亡明显增加,血睾酮含量显著降低。推测,大强度运动训练使大鼠睾丸组织NO过量表达,诱导睾丸组织细胞凋亡明显增多,从而抑制睾酮的分泌。     

Physical Activity Indicators,Metabolic Biomarkers,and Comorbidity in Type 2 Diabetes

ABSTRACT

Purpose: This study aimed (1) to compare physical activity (PA) indicators, metabolic biomarkers, and comorbidity, (2) to investigate the relationship between PA indicators and metabolic biomarkers, comorbidity and (3) to identify barriers to PA in patients with type 2 diabetes (T2DM) who are using oral hypoglycaemic agent (OHA) or combined OHA and insulin (OHAiN). Methods: Sixty-one patients were classified as patients using only OHA or combined OHAiN. Metabolic biomarkers (waist-to-hip ratio, body mass index (BMI), lipid profile, glycosylated haemoglobin (HbA1c), fasting blood glucose, comorbidity and PA indicators (self-reported PA, number of steps (NOS), 6-minute walking distance (6MWD)) were assessed. PA perceptions and reasons for inactivity were questioned. Results: The comorbidity (p = .013), low-density lipoprotein-cholesterol (p = .026), total cholesterol (p = .008) and HbA1c (p = .020) were higher and PA level was lower (p = .007) in the OHAiN group. NOS was positively correlated with high-density lipoprotein-cholesterol (p = .037) and negatively correlated with BMI (p = .007). 6MWD was negatively correlated with BMI (p = .014) and comorbidity (p = .004) in the OHA group. BMI was a significant predictor of NOS (adjusted R² = 0.242) and comorbidity for 6MWD (adjusted R² = 0.250) in the OHA group. The majority of the patients (OHA = 34.3%, OHAiN = 42.3%) reported “lack of time” as the most common barrier to PA. Conclusions: This study showed that patients on OHAiN have lower PA levels, poorer metabolic profiles, and higher comorbidity rates than OHA users. PA indicators were related with some metabolic biomarkers and comorbidity in only OHA users. The most common reason for inactivity was “the lack of time” in both groups.