FDP对运动性疲劳大鼠心肌与血清中酶活性及自由基代谢的影响

为了研究补充FDP对递增运动负荷训练至力竭的运动性疲劳大鼠在运动与恢复期间疲劳的产生、积累和清除这一渐进的、连续的过程中,心肌与血清中SOD、MDA、LDH 和CK的影响及其变化规律.以SD大鼠为研究对象,测定运动训练5周、力竭后即刻、力竭后6h、力竭后24h心肌和血清中LDH、CK、SOD活性和MDA水平,安静对照组(UT)则测定其安静状态下上述相同的实验指标.结果发现:1)中小强度运动训练5周后,FDP组(TT)心肌和血清中各指标与运动对照组(TC)相比均没有显著性差异;2)力竭后即刻及恢复各时相FDP组心肌CK和LDH活性均显著性高于对照组;而血清中却显著性低于运动对照组;3)力竭即刻及恢复各时相,FDP组心肌与血清中SOD活性和SOD/MDA的比值均显著性高于运动对照组,MDA含量显著性低于运动对照组.表明:FDP均能提高运动力竭后即刻及力竭后恢复各时相心肌和血清中SOD的活性和SOD/MDA的比值,抑制MDA的生成;改善心肌内CK和LDH活性,降低血清内CK和LDH活性;说明FDP能促进心肌组织糖酵解,改善心肌的能量供应,提高抗脂质过氧化,加速疲劳的消除,对心肌细胞具有良好的保护作用.     

杜仲提取物对大鼠运动能力的营养干预研究

探讨杜仲提取物(Eucommia ulmoides Oliver extract,EUOE)对大鼠运动能力的营养干预,为EUOAE在运动营养干预中的应用提供实验依据。SD雄性大鼠24只,体重180-220 g,随机分为安静对照组8只、运动训练组8只、运动+EUOE 8只。在最后一次训练后,安静对照组不进行力竭运动训练取材,运动训练组、运动+EUOAE组进行力竭运动,测定其运动至力竭的时间后取材,测定骨骼肌与抗氧化水平相关的生物化学指标。研究结果表明,EUOE可以提高运动训练大鼠骨骼肌抗氧化酶活性、ATPase活性和GSH含量,降低骨骼肌MDA含量和血清LDH、CK活性,延长大鼠跑台运动至力竭时间,具有抗疲劳作用。     

Oxidative stress and antioxidants in tubercular meningitis

Oxidative stress is implicated in the etiopathogenesis of a variety of human diseases. Therefore, in the present study, erythrocyte lipid peroxidation, percentage hemolysis, antioxidant enzymes viz., glutathione reductase, glutathione peroxidase, superoxide dismutase and plasma antioxidants viz., ceruloplasmin, vitamins A,E and C have been determined in 19 patients with tubercular meningitis (TBM) and 50 normals. Six patients who were treated with antibiotics were considered for the follow up. The statistical analysis was carried out by Mann Whitney U test and Wilcoxon rank sum test. Lipid peroxidation (P<0.02), percentage hemolysis (P<0.001) and plasma ceruloplasmin (P<0.0001) of TBM patients were significantly higher, whereas erythrocyte glutathione reductase (P<0.05) and plasma antioxidant vitamins A, E and C (P<0.01, P<0.05 respectively) were significantly lower than those of the controls. In the follow up patients the glutathione reductase and catalase levels were significantly high (P<0.05) compared to their pre-treated condition. Vitamin C and E levels have attained normal range. This study indicated that the blood antioxidant status of TBM patients which was low compared to controls improved after treatment, suggesting the role of free radicals in TBM.     

早期饲喂对肉鸡生长性能和肠道消化酶的影响

为研究早期饲喂对肉鸡生长性能和肠道消化酶的影响,选择360只刚出壳的AA肉用雏鸡,采用单因子试验设计,随机分成4个处理组,每组4个重复,每个重复20只,试验1组出壳后12 h饲喂,试验Ⅱ组出壳24 h后饲喂,试验Ⅲ组出壳36 h后饲喂,对照组出壳48 h后饲喂.饲喂相同日粮,试验期为6周.于21日龄和42日龄分别测定肉鸡进行生产性能和酶活性.结果表明：早期饲喂显著提高了肉鸡的日增重,降低了料重比,试验Ⅰ组和试验Ⅱ组与对照组相比,日增重分别提高了4.19%和3.70%,料重比分别降低5.61%和5.10%,差异显著（P〈0.05）;试验Ⅰ组、试验Ⅱ组和试验Ⅲ组肠道消化酶水平高于对照组.早期饲喂提高了肉鸡肠道消化酶水平,以出壳后12 h饲喂最好.     

Pre-exercise antioxidant enzyme activities determine the antioxidant enzyme erythrocyte response to exercise

Free radical production increases during exercise and oxidative damage occurs in several tissues. We examined the effects of three different exercise tests on the pattern of change of erythrocyte enzyme antioxidant activities. The tests were a short maximal exercise test, a submaximal prolonged exercise test and a cycling stage during competition. The participants were amateur and professional cyclists with different training statuses and different basal erythrocyte antioxidant enzyme activities. The maximal test produced no changes in the erythrocyte antioxidant enzyme activities of amateur sportsmen. The submaximal test, performed at 80% of maximal oxygen uptake, decreased erythrocyte catalase (12%), glutathione peroxidase determined with H₂O₂ (14%) and glutathione reductase (16%); superoxide dismutase activity increased by about 25%. The cycling stage performed by professional cyclists increased erythrocyte catalase (29%) and glutathione reductase (10%) activities. The in vivo changes in glutathione reductase activity were confirmed by in vitro measurements: hydrogen peroxide decreased and the presence of catalase increased the activity of this enzyme. In conclusion, we suggest that the different erythrocyte antioxidant enzyme responses to diverse exercise tests can be explained by the effects of hydrogen peroxide and the superoxide anion on the antioxidant enzyme activities in erythrocytes.     

Probing transient protein-mediated DNA linkages using nanoconfinement

We present an analytic technique for probing protein-catalyzed transient DNA loops that is based on nanofluidic channels. In these nanochannels, DNA is forced in a linear configuration that makes loops appear as folds whose size can easily be quantified. Using this technique, we study the interaction between T4 DNA ligase and DNA. We find that T4 DNA ligase binding changes the physical characteristics of the DNA polymer, in particular persistence length and effective width. We find that the rate of DNA fold unrolling is significantly reduced when T4 DNA ligase and ATP are applied to bare DNA. Together with evidence of T4 DNA ligase bridging two different segments of DNA based on AFM imaging, we thus conclude that ligase can transiently stabilize folded DNA configurations by coordinating genetically distant DNA stretches.