谷胱甘肽、自由基在砷剂诱导卵巢癌细胞凋亡中的作用

目的　观察谷胱甘肽、自由基在砷剂诱导卵巢癌细胞凋亡中的作用。方法　砷剂孵育卵巢癌细胞 4 8h后 ,琼脂糖凝胶电泳及流式细胞仪检测细胞凋亡 ,分光光度法检测细胞内谷胱甘肽、活性氧及丙二醛含量。结果　砷剂具有诱导卵巢癌细胞凋亡作用 ,砷剂诱导后细胞内谷胱甘肽含量减少 (P <0 .0 1)、活性氧及丙二醛含量增加(P <0 .0 5 )。结论　氧化还原系统的改变是砷剂诱导卵巢癌细胞凋亡的重要途径之一。     

活性氧簇在皮炎湿疹发病中的作用

活性氧簇是重要的氧的衍生物,氧化还原反应状态的平衡对维持机体的内环境起着重要的作用.皮肤是氧应激损害的主要靶器官,过多活性氧造成组织损伤,其主要通过影响核因子-κB、NO、蛋白激酶介导的磷酸化和基因异常表达发挥作用.多种炎症性皮肤疾病与活性氧簇相关,活性氧簇在皮炎、湿疹的发病中起着重要作用,抗氧化剂有望成为治疗这类疾病的新途径.     

Effects of cepharanthin on neutrophil chemotaxis, phagocytosis, and reactive oxygen species generation.

The effects of cepharanthin on inflammatory parameters such as neutrophil chemotaxis, phagocytosis and reactive oxygen species (ROS) generation, were examined. Cepharanthin significantly decreased the levels of O2-, H2O2, and OH. generated by neutrophils. H2O2 and OH. generated in a cell-free, xanthine-xanthine oxidase system were also reduced in the presence of cepharanthin. However, the drug did not affect neutrophil chemotaxis or phagocytosis. The present study indicates that cepharanthin is an effective ROS scavenger, exerting its anti-inflammatory action by reducing the potent ROS species excessively generated in tissues and organs, especially at the sites of inflammation.     

Improvement of endoneurial lipid abnormalities in experimental diabetic neuropathy by oxygen modification

Endoneurial hypoxia and a high frequency of closed capillaries have been found in chronic experimental diabetes and human diabetic sural nerve, respectively. These findings have led to the hypothesis that the pathogenesis of diabetic neuropathy is due to endoneurial hypoxia. To evaluate the role of endoneurial hypoxia in experimental diabetic neuropathy, the effects of supplementation and deprivation of oxygen on peripheral nerve lipid biosynthesis were studied in normal control and streptozotocin-induced diabetic rats. Defective lipid biosynthesis in diabetic nerve was partially prevented by oxygen supplementation. When normal rats were placed in a hypoxic chamber, lipid abnormalities similar to those observed in diabetic nerves were demonstrated in the absence of changes in nerve free sugars. These findings suggest that endoneurial hypoxia may underlie some key biochemical abnormalities encountered in experimental diabetic neuropathy.     

Maximal and submaximal oxygen uptake during running: how should body mass be accounted for?

Oxygen uptake during running, i.e., the running economy, is an important factor in determining running performance in endurance events. The relation to performance is particularly strong when the aerobic running capacity is calculated, i.e., when running economy is related to the maximal oxygen uptake. There is considerable interindividual variation in running economy, and the reason for this is only partly understood. To some extent, this may be due to the way in which the oxygen uptake during running is usually expressed. This may expecially be true when subjects with different or changing body masses are compared. Several lines of evidence, including earlier animal studies as well as more recent human studies, favor the expression of submaximal and maximal oxygen uptake during running in terms of ml · kg^−0.75· min⁻¹ rather than as ml · kg⁻¹· min^−1.     

Autotransfusion after open heart surgery: the oxygen delivery capacity of shed mediastinal blood is maintained

Autotransfusion of mediastinal shed blood after open heart surgery has become a common and accepted procedure in reducing the need for homologous transfusion during the last 15 years. The objectives of the present study were to investigate the oxygen delivery capacity of autotransfused shed mediastinal blood, compared to patient-blood, during cardiopulmonary bypass and in the postoperative period.
Ten consecutive patients undergoing elective cardiac surgery were studied. Mediastinal shed blood was collected in the cardiotomy reservoir and retransfused during the first 18 postoperative hours. The oxygen delivery capacity of the blood to the tissues was calculated by use of the oxygen status algorithm (OSA 2.0) programme and measurement of the 2,3-diphosphoglycerate (2,3-DPG) concentration.
Autotransfusion volume ranged from 450–1530 ml per patient (median 824 ml). Shed blood had a mean haemoglobin level of 8.8 g/dl and 7.4 g/dl at 1 h and 6 h of autotransfusion, respectively. There were no significant changes of 2,3-DPG concentration in the patient-blood during cardiopulmonary bypass or after autotransfusion compared to preoperative values. P50 for oxygen (3.6 and 3.6 kPa) and 2,3-DPG concentrations (5.3 and 5.1 mikromol/ml erythrocyte) in shed mediastinal blood (1h and 6h postoperatively) were not significantly different compared to patient-blood.
The results demonstrate that the oxygen delivery capacity of shed mediastinal blood is maintained and that the oxygen affinity of patient-blood is not influenced by autotransfusion.     

Fluctuating PEEP (F–PEEP) versus conventional PEEP in dogs with asymmetrical lung injury

Fluctuating PEEP (F-PEEP) is a newly developed PEEP in which end-expiratory pressure (EEP) is periodically changed within a certain range. In a dog model with unilateral lung injury induced by the introduction of hydrochloric acid, F-PEEP in which the EEP was periodically changed from 0.5 to 1.5 kPa at periods of 6 min, and conventional PEEP (C-PEEP) with an optimized EEP of 1.0 kPa, were each applied for 30 min. F-PEEP produced a significantly greater improvement of PaO2 and intrapulmonary shunt (QS/QT) than C-PEEP, and at the low EEP phase, the greatest improvement accompanied by an increased dynamic compliance and a large cardiac output was obtained. These results suggest that F-PEEP provides a useful mode of artificial ventilation for the treatment of unilateral lung injury.     

长期居住海平面后藏族经受急性减压低氧时的体力活动能力

本研究从急性低氧对移居海平面后藏族的体力活动能力的影响来探索藏族的高原低氧适应机制。结果揭示藏族的最大体力负荷强度没有显著下降，最大氧耗和氧脉搏也没有明显变化，动脉血氧饱和度明显高于汉族，这更显示藏族对高原低氧适应机制有独特之处。推测可能是藏族在氧的摄取、传递和释放过程比汉族更有利于对高原低氧环境的适应。     

海拔3417m世居及移居者无氧代谢阈与左心功能关系的探讨

在海拔３４１７ｍ对１８名健康世居藏族和１６名移居汉族用Ｊｅａｇｅｒ气体代谢自动分析系统和心阴抗图测定了无氧阈和最大摄氧量时的ＳＶ、ＣＯ、ＰＥＰ／ＬＶＥＴ和ＳａＯ２。结果显示：在海拔３４１７ｍ测得ＡＴ值明显低于海平面；世居藏族ＡＴ出现较晚，并且ＡＴ时的功率、ＶＯ２、ＭＶ、ＨＲ、ＣＯ、ＳＶ均高于移居汉族，而ＰＥＴ／ＬＶＥＴ比值小于移居组；两组的ＳＶ峰值出现时间不同，蕊居组在ＡＴ或ＡＴ以后出现的占７２％     

高压氧对急性移植物抗宿主病小鼠细胞因子表达的影响

目的:观察高压氧(HBO)对骨髓移植时急性移植物抗宿主病(aGVHD)小鼠脾组织中细胞因子表达的影响,探讨HBO抗aGVHD的作用机制.方法:应用直线加速器排空C57BL/6小鼠骨髓后,注入BALB/C小鼠骨髓与脾淋巴细胞的混合液,复制aGVHD模型.应用RT-PCR技术检测经HBO、环孢素A(CsA)、氨甲喋呤(MTX)处理后,小鼠脾组织中白细胞介素2(IL-2)、肿瘤坏死因子α(TNF-α)、白细胞介素4(IL-4)及白细胞介素10(IL-10)mRNA水平的变化.结果:HBO组小鼠11d的生存率明显高于异基因移植组及CsA MTX组;HBO组小鼠脾组织中TNF-α和IL-2mRNA相对含量显著低于异基因移植组(P＜0.05)、显著高于CsA MTX组;HBO组小鼠脾组织中IL-4和IL-10 mRNA相对含量显著高于异基因移植组及CsA MTX组(P＜0.05).结论:HBO可能通过调节促炎/抑炎细胞因子的分泌而发挥其明显的抗aGVHD作用.