Effects of Walking Speed on Total and Regional Body Fat in Healthy Postmenopausal Women

Introduction: This study had two aims: (1) To confirm the efficacy of exercise speed and impulse (session duration at a given speed) to produce total and abdominal fat loss in postmenopausal women, and (2) compare the exercise speed and impulse necessary for the stimulation of fat loss to the suppression of bone mineral loss. Of special interest was to compare these parameters of exercise on fat loss in the same study and with the same subjects where they were found to suppress bone mineral loss. We hypothesized that (1) more total fat will be lost with slow walking and a longer impulse than with fast speed and shorter impulse, and (2) more abdominal subcutaneous (SC) and visceral fat (VF) will be lost with fast walking speed. Materials and Methods: Fat loss and suppression of bone mineral loss were measured in the same 25 subjects after 15 weeks, and fat measurements were also taken after 30 weeks in 16 residual subjects. Study parameters were walking a 4.8 km distance 4 days/week at either 6.6 km/h (120% of ventilatory threshold (VT)) or at 5.5 km/h (101.6% of VT) and expending 300 kcal/session. Body composition (fat and lean body mass, LBM) was measured with dual-energy X-ray absorptiometry (DXA) and anthropometric methods. Results: Slow walkers in the residual group progressively lost a significant percent of total body fat over 30 weeks while no such loss occurred after 15 weeks in fast walkers in either group, supporting hypothesis 1. However, the 20% higher starting body fat in 16 residual slow relative to fast subjects suggests that exercise fat loss is greater in overweight than in lean subjects. In fast walkers, fat loss occurred after 30 weeks of training. Hypothesis 2 was not supported as both speeds led to equal VF loss in 30-week group as estimated by waist circumference (CF) confirming that VF responds to the magnitude of energy expenditure and not the walking speed. Conclusions: Total body fat is lost through walking at all speeds, but the change is more rapid, clear, and initially greater with slow walking in overweight subjects. A longer exercise impulse at a lower speed in our study initially produced greater total fat loss than a shorter one with fast walking speed. This was reversed in comparison to how the same exercise in the same subjects suppressed bone mineral loss. Data from other studies indicate that longer impulses may promote greater fat loss at both slow and high exercise speeds, and our study providing only a 4.8 km walking distance may have limited the walking impulse and the magnitude of fat loss. Increased exercise energy expenditure at either walking speed produces equivalent declines in visceral fat in postmenopausal women, and with sufficiently long impulses, should reduce disabilities associated with central obesity.     

Understanding the association between psychomotor processing speed and white matter hyperintensity: A comprehensive multi‐modality MR imaging study

Cognitive processing speed is crucial for human cognition and declines with aging. White matter hyperintensity (WMH), a common sign of WM vascular damage in the elderly, is closely related to slower psychomotor processing speed. In this study, we investigated the association between WMH and psychomotor speed changes through a comprehensive assessment of brain structural and functional features. Multi‐modal MRIs were acquired from 60 elderly adults. Psychomotor processing speeds were assessed using the Trail Making Test Part A (TMT‐A). Linear regression analyses were performed to assess the associations between TMT‐A and brain features, including WMH volumes in five cerebral regions, diffusivity parameters in the major WM tracts, regional gray matter volume, and brain activities across the whole brain. Hierarchical regression analysis was used to demonstrate the contribution of each index to slower psychomotor processing speed. Linear regression analysis demonstrated that WMH volume in the occipital lobe and fractional anisotropy of the forceps major, an occipital association tract, were associated with TMT‐A. Besides, resting‐state brain activities in the visual cortex connected to the forceps major were associated with TMT‐A. Hierarchical regression showed fractional anisotropy of the forceps major and regional brain activities were significant predictors of TMT‐A. The occurrence of WMH, combined with the disruption of passing‐through fiber integrity and altered functional activities in areas connected by this fiber, are associated with a decline of psychomotor processing speed. While the causal relationship of this WMH‐Tract‐Function‐Behavior link requires further investigation, this study enhances our understanding of these complex mechanisms.     

Regional differences in extracellular ascorbic acid levels in the rat brain determined by high speed cyclic voltammetry

High speed cyclic voltammetry was used in combination with pressure ejection of ascorbate oxidase for the determination of extracellular ascorbic acid within the brain of the anaesthetized rat. Large variations in absolute levels of ascorbate were found between animals although distribution patterns showed a good degree of reproducibility. Ascorbate levels in the white matter of the corpus callosum were found to be higher than in adjacent areas of grey matter (striatum and cortex).     

脑卒中偏瘫患者步行速度变化的研究

目的该文通过对脑卒中偏瘫患者步行速度的变化与病程关系的研究,探讨脑卒中偏瘫患者步行速度恢复的规律。方法35例发病后6周内进行步行功能训练的的脑卒中偏瘫患者,连续进行12周的步行速度评测。步行速度测量方法采用10m最大步行速度测定方法。结果脑卒中偏瘫患者最大步行速度的变化与病程呈近似双曲线函数关系Y=A-B/X(R2=0.971)。结论脑卒中偏瘫患者的步行速度恢复的变化是有规律的,而且是可以预测的。     

基于MEMS传感器的可穿戴式老年人跌倒监测系统的设计

为了缩短老年人跌倒后的救助时间和提高安全保障,我们设计了一种基于加速度和角速度传感器的跌倒监测装置。该装置结合机械微电子系统(microelectro mechanical system,MEMS)传感器、数字信号处理及无线传输技术应用于智能手机上。为区分人体跌倒事件和日常行为,结合人体三轴加速度和角速度联合对跌倒事件进行判断,通过大量实验选取合适阈值。针对老年人的生活特点,数据通过蓝牙装置发送至手机上进行处理,通过手机语音报警、手机GPS定位系统和短信通知医院和用户监护人,使得老年人跌倒后能够在第一时间获得救治,减小伤害。经过大量的实验测试结果统计,相比较于传统的三轴加速度判断跌倒事件,结合三轴加速度和加速度联合判断使该系统的准确率从84.29%提高至100%。结果表明:基于MEMS传感器的可穿戴式跌倒监测系统具有便捷、准确、功耗低的特点,能够准确监测出跌倒事件并进行报警。     

复方丹参滴丸人含药血清中丹参相关代谢产物的分析

目的:研究复方丹参滴丸人含药血清中丹参相关代谢产物,推测其代谢机制. 方法:柱切换-高效液相色谱法富集和分离血清样品中的代谢物,电喷雾离子阱质谱法进行检测,多级质谱技术确定代谢物的碎片结构,推测其结构. 结果:在人含药血清中检测到了5个新的代谢产物,分析了各代谢物的体内形成机制. 结论:本研究可为复方丹参滴丸体内物质基础的研究打下基础.     

高速逆流色谱快速分离制备石椒草中高纯度芦丁对照品

[目的]建立高速逆流色谱法高效、快速分离制备石椒草中芦丁的新方法.[方法]石椒草的乙醇提取物经大孔吸附树脂柱初步分离后,直接进行高速逆流色谱分离,所用两相溶剂体系为乙酸乙酯-正丁醇-水(2:1:3,v/v/v),上相为固定相,下相为流动相,流速1.5 mL/min,转速830 r/min,检测波长254 nm,所得产物的纯度经HPLC检测,结构经UV和Ms鉴定.[结果]经一步分离从200 mg石椒草粗提物中得到纯度高于99%的芦丁,分离时间短于2 h.[结论]由该法制备芦丁简便、快速,所得产物纯度高,适合于芦丁对照品的大规模制备.     

Relationship between sarcopenia,six‐minute walk distance and health‐related quality of life in liver transplant candidates

Sarcopenia, or loss of skeletal muscle mass, is associated with increased mortality and morbidity in liver transplant (LT) candidates. Six‐minute walk distance (6MWD) and health‐related quality of life (HRQOL) as assessed by short form 36 scores (SF‐36) also impact clinical outcomes in these patients. This study explored the relationship between the sarcopenia, 6MWD, and HRQOL in LT candidates. Sarcopenia was evaluated based on skeletal muscle mass index (SMI) quantified from abdominal computed tomography. Patients were followed until death, removal from the wait list or the end of the study period. Two hundred and thirteen patients listed for LT were included. The mean SMI, 6MWD and mean gait speed were 54.3 ± 9.7, 370.5 m and 1 m/s, respectively. Sarcopenia was noted in 22.2% of LT candidates. There was no correlation between sarcopenia, 6MWD, and SF‐36 scores. The 6MWD, but not sarcopenia, was an independent predictor of mortality (hazard ratio = 2.1 [0.9–4.7]). In summary, sarcopenia did not emerge as a significant predictor of waitlist mortality and also failed to correlate with either functional capacity or HRQOL in LT candidates. In patients with ESLD awaiting LT, 6MWD appears to be a more useful prognostic indicator than the presence of sarcopenia.