Oxidative stress in elite athletes training at moderate altitude and at sea level

Using a controlled parallel group longitudinal trial design, we investigated the effects of different training interventions on the prooxidant/antioxidant status of elite athletes: living and training at moderate altitude for 3 (Hi-Hi3) and 4 weeks (Hi-Hi), and for 4 weeks too, living high and training high and low (Hi-HiLo) and living and training at sea level (Lo-Lo). From 61 swimmers, 54 completed the study. Nitrites, carbonyls, and lipid peroxidation (LPO) levels were assessed in plasma. Enzymatic antioxidants glutathione peroxidase (GPx) and glutathione reductase (GRd), and non-enzymatic antioxidants total glutathione (GST), reduced glutathione (GSH) and oxidized glutathione (GSSG) were analysed in the erythrocyte fraction. At the end of the intervention, nitrites levels were similar in all altitude groups but higher than in the Lo-Lo controls (P?=?.02). Hi-HiLo had greater GPx activity than Hi-Hi and Hi-Hi3 during most of the intervention (P?≤?.001). GRd activity was higher in Lo-Lo than in Hi-Hi at the end of the training camp (P?≤?.001). All groups showed increased levels of LPO, except Lo-Lo, and carbonyls at the end of the study (P?≤?.001). Training at altitude for 3 or 4 weeks drives oxidative stress leading to cellular damage mainly by worsening the antioxidant capacities. The GSSG/GSH ratio appears to be related to perceived exertion and fatigue. The stronger antioxidant defence showed by the Hi-HiLo group suggests an inverse relationship between redox alterations and performance. Further studies are required to investigate the role of oxidative stress in acclimatization, performance, and health.     

两种体系中甘氨酸合铜配合物稳定常数的测定

采用pH电位滴定法研究了甘氨酸水溶液和甘氨酸钠水溶液两种体系中甘氨酸与铜离子间的配位作用,测定了两种体系中甘氨酸与铜配合物的逐级稳定常数;对影响测定准确度的原因进行了详细的分析,采用Origin 6.0计算机软件包来处理实验数据和作图。     

荧光光谱法研究Fe~（2＋）和Fe~（3＋）与牛血清白蛋白的竞争结合作用

利用荧光光谱法、紫外吸收光谱法、同步荧光法和三维荧光法研究了金属离子Fe2＋、Fe3＋与牛血清白蛋白（BSA）在模拟生理条件下的竞争结合作用.结果表明,Fe2＋、Fe3＋对BSA的内源荧光都有明显的猝灭作用,猝灭机理均为静态猝灭和动态猝灭的联合作用,主导作用分别为静态猝灭和动态猝灭,并分别计算了结合常数、结合位点数和热力学参数,Fe3＋与BSA的结合能力强于Fe2＋.弱的结合力使BSA与Fe2＋、Fe3＋相互作用后构型没有明显改变.当Fe2＋、Fe3＋同时与BSA相互作用时,二者表现出弱的竞争取代现象.     

关于氯甲基膦酸性质的研究

介绍氯甲基膦酸的合成方法、纯品的制备和主要用途以及氯甲基膦酸的物理化学性质.重点是对该化合物的酸性进行了研究,利用电位滴定法绘出了滴定曲线.研究表明,氯甲基膦酸为二元酸,可以进行二级电离.在测定温度(27℃)下,其浓度平衡常数Kα_1和Kα_2分别为1.29×10~(-2)、6.82×10~(-7);活度平衡常数K’α_1和K’α_2分别为1.26×10~(-2)和6.51×10~(-7).     

微型滴定法测定自来水中Cl-的含量

利用自制微型化学实验仪器,通过微型滴定法测定自来水中Cl-的含量.实验表明这种微型测定方法具有简便经济,反应灵敏,快速准确的特点.值得在化学实验教学中推广.     

环烷酸中脂肪酸含量测定方法的改进

讨论了尿素络合酸碱“滴定法”测定从煤、柴油碱碴生产的环烷酸中脂肪酸含量的测定条件和干扰因素并与尿素络合“重量法”进行了比较,“滴定法”比“重量法”操作简单且操作耗时少,而精确度比“重量法”有所提高.该分析方法当环烷酸中脂肪酸的含量为1%～2%时,相对误差不大于6%,变异系数不大于5%;当环烷酸中脂肪酸的含量为1%～2%,而加标量为样品中脂肪酸含量的1倍左右时回收率80%左右.     

酸碱滴定误差公式的几种推导方法

讨论了从ＣＢＥ和ＭＢＥ、ＰＢＥ以及溶液本身平衡出发来推导滴定误差公式的三种不同方法．     

海洋浮游藻类细胞外碳酸酐酶活性分析

分析了海洋浮游藻类细胞外碳酸酐酶（细胞外ＣＡ）活性与无机碳浓度以及藻细胞质膜氧化还原活性之间的关系．     

鲜枣中Vc含量的测定及方法比较

采用碘量法和2,6-二氯靛酚滴定法两种方法对样品鲜枣中维生素C含量的测定,比较两种方法结果表明,2,6-二氯靛酚滴定法的精密度更好,而碘量法操作快捷,适应于即时测定。     

高强度运动对氧化-抗氧化内稳态的提升

为了探讨高强度训练对SD大鼠OAH品质的提高,将30只SD大鼠随机分为训练干预组与安静对照组。训练干预组以坡度10%、28 m/min、每次60 min、每天1次、每周5 d条件下于跑台上运动8周;安静对照组不施加运动干预措施。在最后一次训练结束72 h即刻进行腓肠肌与血清的取材。检测指标为骨骼肌与血清的丙二醛(malondialdehyde,MDA)、总超氧化物歧化酶(total super oxide dismutase,TSOD)、过氧化氢酶(catalase,CAT)和还原型谷胱甘肽(reduced glutathione,RGSH)。结果发现:骨骼肌与血清中的RGSH含量和TSOD活性显著性增高;MDA在血清中显著性降低,但在骨骼肌中显著性升高;CAT活性在血清中显著性增高,但在骨骼肌中不变。实验表明:高强度训练能够实现SD大鼠OAH升级。