乳癌细胞核DNA含量与预后

本文应用流式细胞术(Flow Cytometry,FCM)检测了102例石蜡包埋的乳癌组织的细胞核DNA含量,并探讨了DNA指数(DNA Index.DI)和S期细胞比例(S-phase Fraction,SPF)与临床预后因素及病人术后生存状况的关系。结果显示:16例为DNA二倍体,8例近二倍体,78例(77％)非整倍体。非整倍体癌较二倍体/近二倍体癌的SPF高。DI值与组织学分级、淋巴结状况、原发肿瘤大小和临床分期密切相关,而与病人诊断时的年龄无关。淋巴结转移阳性组较阴性组、晚期肿瘤(Ⅲ、Ⅳ期)比早期肿瘤(Ⅰ、Ⅱ期)的DI值高(P<0.05),而非整倍体率仅有降低的趋势但无显著性差异,说明DI值作为一个预后参数比倍性分析统计效率高。SPF与病人的各预后因素及生存情况无明显关系。二倍体/近二倍体癌病人较非整倍体癌病人的生存率高、无瘤生存时间长,说明流式细胞术DNA含量测定确实可为乳癌病人的预后提供有价值的信息。     

A model study of optimal training reduction during pre-event taper in elite swimmers

The aim of this study was to assess responses to taper in elite athletes using computer simulations. Parameters of a non-linear model were derived from training and performance data over two seasons for eight elite swimmers. The fit between modelled and actual performances was statistically significant for each swimmer (r(2) = 0.56 +/- 0.06; P < 0.01). The simulations were used to estimate characteristics of step and progressive tapers that would maximize performance either (1) after regular training only or (2) after overload training of a 20% step increase in regular training for 28 days. The highest performance with a step taper was greater with than without prior overload training (101.4%, s = 1.6 vs. 101.1%, s = 1.4 of personal record; P < 0.01) but required a longer taper duration (22.4 days, s = 13.4 vs. 16.4 days, s = 10.3; P < 0.05). The optimal progressive taper led to a better performance only after the overload period (101.5%, s = 1.5; P < 0.001). Negative and positive influences of training were estimated as indicators of fatigue and adaptations to training respectively. During the optimal taper, the negative influence was completely removed, independently of the prior training, whereas the positive influence increased only after overload training. Our computer simulations show that the characteristics of an optimal training reduction in elite athletes depend on the training performed in the weeks prior to a taper.     

Are preschool children active enough? Objectively measured physical activity levels

The present study aimed to describe accelerometer-based physical activity levels in 4- and 5-year-old children (N = 76) on 2 weekdays and 2 weekend days. The children were sedentary for 9.6 hr (85%) daily, while they engaged in moderate to vigorous physical activity (MVPA) for 34 min (5%). Only 7% of the children engaged in MVPA for 60 min per day, and only 26% reached the standard of 120 min of total activity. Their engagement in MVPA did not significantly differ between weekend and weekdays. Mean activity counts and minutes in MVPA did not differ between genders. Physical activity levels in this sample of preschool children were far lower than recommended.     

Explaining international sporting success: An international comparison of elite sport systems and policies in six countries

The aim of this article is to explore the relationship between elite sport policy systems (inputs and throughputs) and success in international competitions (outputs). A conceptual model of the sports policy factors, which lead to international sporting success, was implemented in an empirical environment in a pilot study with six nations. The study has sought to operationalise nine pillars, or key drivers in elite sport systems, into measurable concepts, which can be aggregated into an overall score for each pillar. In addition to a national sport policy questionnaire, athletes, coaches and performance directors were also involved in the collection of qualitative and quantitative data. Although the results are inconclusive, the findings suggest that some pillars could be regarded as possible drivers of an effective system because they were prioritised in the most successful sample nations: financial resources (pillar 1), athletic and post-career support (pillar 5), training facilities (pillar 6) and coach development (partly pillar 7).     

二手房市场:现状·问题·对策

随着房产市场的快速发展。全国房产“涨”声一片,主观上的市场经济不够完善、市场信息不够对称、市场主体行为不够规范以及客观上土地的稀缺、消费者对房产的投机行为、地方政府的变相鼓励,使得房产市场泡沫现象逐渐凸现并发展起来,造成房价飞涨,而人们购买力的相对下降,开发商处于永恒的利润最大化,都使得住房一级市场供需失衡,从而使越来越多的关注投入到了房产的二级市场,通过积极挖掘二手房市场的巨大潜力来满足住房主体的住房需求。     

Patterns of perceptual deficits in academically deficient juvenile delinquents

Patterns of perceptual deficits were investigated in a population of academically deficient juvenile delinquents. Comparisons were made with a group of youthful offenders with adequate academic skills. Auditory perceptual deficits appeared to be a more significant factor in accounting for the severe academic deficiencies observed in the delinquent subjects than did visual-perceptual deficits. However, multiple perceptual deficits involving both auditory and visual perceptual skills formed the basis of the majority of academic deficiencies and social maladaptation. The results indicate the potential ill effects of an undiagnosed and untreated learning disability on subsequent emotional development. Prevention of delinquency may begin with the preschool child who is at high-risk for developing behavioral problems in later years.     

Anaerobic capacity, isometric endurance, and Laser sailing performance

Laser sailors have to tolerate fatiguing contractions of the lower-body muscles for prolonged periods. The aims of the present study were (1) to evaluate the difference between top-ranked and club sailors, in their capacity to resist fatigue during sustained isometric and maximal power exercise, and (2) to examine the relationships between the above parameters and performance on a Laser simulator and competitive racing performance according to the national ranking list. Eight Greek nationally ranked Laser sailors were compared with eight club sailors. Each sailor performed: (a) an effort to the limit of tolerance on the Laser simulator, (b) an effort to the limit of tolerance of isometric endurance for the right leg on an isokinetic dynamometer, and (c) a Wingate test of maximal lower-body anaerobic power on a cycle ergometer. In the nationally ranked sailors, isometric endurance time (mean 160 s, s = 50) and endurance time on the Laser simulator (1381 s, s = 1354) were significantly (P < 0.05) longer than in the club sailors (101 s, s = 29 and 565 s, s = 367, respectively), whereas the final minute heart rate (in both groups: 149 beats . min(-1), s = 22) and the mean arterial pressure (nationally ranked sailors: 129 mmHg, s = 16; club sailors: 120 mmHg, s = 21) on the Laser simulator were not different between groups. During the Wingate test, the nationally ranked sailors had a significantly lower index of fatigue (42%, s = 5) than the club sailors (49%, s = 6). Isometric endurance time was significantly correlated with the Wingate index of fatigue (r = -0.73; P < 0.001). The nationally ranked sailors' mean and maximal anaerobic powers were significantly correlated with their national ranking positions (r = -0.83 and -0.71, respectively). It is suggested that isometric endurance and anaerobic power are well-developed in Laser class sailors and may influence their sailing performance. Furthermore, compared with club sailors, the nationally ranked sailors are able to sustain the same intensity of lower-limb isometric contractions for much longer with similar cardiovascular responses.     

Physiological determinants of climbing-specific finger endurance and sport rock climbing performance

The aim of the study was to examine several physiological responses to a climbing-specific task to identify determinants of endurance in sport rock climbing. Finger strength and endurance of intermediate rock climbers (n = 11) and non-climbers (n = 9) were compared using climbing-specific apparatus. After maximum voluntary contraction (MVC) trials, two isometric endurance tests were performed at 40% (s = 2.5%) MVC until volitional exhaustion (continuous contractions and intermittent contractions of 10 s, with 3 s rest between contractions). Changes in muscle blood oxygenation and muscle blood volume were recorded in the flexor digitorum superficialis using near infra-red spectroscopy. Statistical significance was set at P < 0.05. Climbers had a higher mean MVC (climbers: 485 N, s = 65; non-climbers 375 N, s = 91) (P = 0.009). The group mean endurance test times were similar. The force-time integral, used as a measure of climbing-specific endurance, was greater for climbers in the intermittent test (climbers: 51,769 N x s, s = 12,229; non-climbers: 35,325 N x s, s = 9724) but not in the continuous test (climbers: 21,043 N x s, s = 4474; non-climbers: 15,816 N x s, s = 6263). Recovery of forearm oxygenation during rest phases (intermittent test) explained 41.1% of the variability in the force-time integral. Change in total haemoglobin was significantly greater in non-climbers (continuous test) than climbers (P = 0.023--40% test timepoint, P = 0.014--60% test timepoint). Pressor responses were similar between groups and not related to the force-time integral for either test. We conclude that muscle re-oxygenation during rest phases is a predictor of endurance performance.     

Measurement of maximal muscle cross-sectional area of the elbow extensors and flexors in children, teenagers and adults

The aims of this study were to examine age and sex differences in elbow extensor and flexor anatomical muscle cross-sectional area (mCSA) measured by magnetic resonance imaging (MRI) and the location of maximal mCSA as a percentage of the distance from the distal to the proximal end of the humerus. Ninety-five individuals spread across the age groups 9 - 10 years, 16 - 17 years and ?21 years participated in the study. Muscle cross-sectional area derived from the manual MRI tracing proved to be highly reliable in terms of limits of agreement (-2.5 to 1.5 cm(2)) and the intraclass correlation coefficient (ICC = 0.998). A sex-by-age group analysis of variance revealed significant effects (P < 0.01) of sex, group and a sex-by-group interaction, the latter reflecting a greater increase in males than females of upper arm mCSA from childhood to adulthood. Extensor mCSA was more proximal (55 +/- 6%) than that of the flexors (28 +/- 6%). A significant effect (P < 0.01) of group was found for location of maximal extensor mCSA, reflecting its more distal position with increasing age. Measurements of muscle size should be made at the individually determined position of maximal mCSA if interpreting data collected during growth and maturation, especially if the muscle group of interest is the elbow extensors and if different age groups are being monitored.