Changes in enzyme activities of glycerolipid metabolism of guinea-pig cerebral hemispheres during experimental hypoxia

Hypoxic treatment causes changes of some enzymatic activities involved in the glycerolipid metabolism in subcellular fractions of guinea pig cerebral hemispheres. The activity of lysophosphatidylcholine acyltransferase, choline phosphotransferase, glycerol-3-phosphate acyltransferase(s), as well as the activity of triacylglycerol lipase significantly decreased in the microsomes of cerebral hemispheres of animals intermittently exposed to hypoxic treatment for eighty hours. At the same time, a marked activation of microsomal and mitochondrial phospholipase A₂ occurred. The changes of the above-mentioned enzymatic activities after the hypoxic treatment correlated well with the increase in the level of brain and blood free fatty acids. The changes also correlated with the decrease of labeled lipid precursors incorporated into lipids of the cerebral hemispheres, observed during oxygen insufficiency.     

低氧适应兔肺超微结构观察

家兔暴露于低压舱,每天4h,连续2周。第一周与第二周的模拟海拔高度分别为3800m和5000m。阶梯低氧适应后,适应组与急性低氧组家兔一同暴露于模拟海拔5000m,停留3h。暴露后家兔和正常对照家兔(n=5)均进行了电镜观察。结果发现,急性低氧兔肺毛细血管内皮明显肿胀,有时因毛细血管内皮明显隆出而使毛细血管腔变小。而在低氧适应组,肺毛细血管内皮肿胀程度减轻,同时也未见因内皮膨出而使毛细血管腔变小的现象。文章还讨论了本观察结果的生理意义。     

不同海拔地区适应人群脾脏肿大的原因分析

对海拔2880米～4120米地带552名健康移居者进行检测,检出高原性脾肿大34例。结果表明,31～40岁年龄带脾脏增大人数增高明显,随年龄梯度习服者改变,有减少趋势,脾脏改变有个体差异和解剖关系差异。本文认为,高原缺氧红细胞代偿性增多,加重脾脏负担。缺氧直接刺激网状内皮系统增生。血液流变学和动力学改变等因素,引起脾脏肿大。     

HYPOXIC INHIBITION OF BREATHING AND MOTOR ACTIVITY IN THE FOETUS AND NEWBORN

In fetal animals hypoxia of rapid onset causes cessation of breathing movements, electro-ocular activity and decrease of muscle tone. These effects last several hours and are in contrast to the hypernoea and behavioural activation which occurs during hypoxia soon after birth and in the adult. Transection and lesion studies in fetal sheep suggest that hypoxia activates a descending inhibition of respiratory and other motor activities which either originates in the pons or is conveyed to medullary and spinal levels of the neuraxis by fibres through the pons in the region of the Kolliker-Fuse nucleus. Recently, using FOS immunohistochemistry we have identified cells in the medial parabrachial complex which are activated by hypoxia in fetal sheep, but not newborn lambs. It is proposed that these cells have descending inhibitory connections with respiratory and spinal motor pathways, but the precise anatomy and neuro-chemistry of such pathways is unknown. It is not known if the parabrachial cells are directly sensitive to low P o₂ or receive input from other centres or peripheral receptors which monitor arterial P o₂ in the foetus. Nor is it known why these cells are not activated by low P o₂ after birth.     

13C NMR spectroscopy study of cortical nerve cell cultures exposed to hypoxia

Primary cultures of cerebral cortical GABA-ergic neurons growing on top of a preformed layer of astrocytes (co-cultures) were incubated with [1-¹³C]glucose and exposed to a low oxygen atmosphere (2% O₂) for 17 hr. ¹³C, ¹H, and ¹³P nuclear magnetic resonance (NMR) spectroscopy was performed on perchloric acid (PCA) extracts of cells and of media collected from these cultures. In the control groups incorporation of ¹³C label into glutamine, citrate, and lactate could be demonstrated in both cell extracts and culture media. Labeled GABA and glutamate were only observed in cell extracts. During hypoxia high energy phosphates decreased but lactate production and glucose consumption increased. There was a decreased amount of citrate and glutamine in cell extracts and media of the hypoxic co-cultures. There was a change in distribution of the ¹³C label within the GABA molecule, with an increase of labeling in the C-2 position. This change in ¹³C distribution was not found in glutamine present in the media where it is a precursor for GABA in neurons. Instead a decrease in the corresponding C-4 position was observed. These results suggest that energy depletion during hypoxia leads to reduced export from the astrocytic tricarboxylic acid (TCA) cycle as demonstrated by a decreased amount of citrate and changed distribution of ¹³C in glutamine. The change in the distribution of label in GABA from cell extracts as compared to glutamine in the medium may indicate that neurons are synthesizing GABA using precursors supplied from their own TCA cycle and not from precursors supplied by astrocytes.     

利氧灵提高人体高原劳动能力效果评价

本文通过高原现场观察,对利氧灵提高人体高原劳动能力的效果进行了评价。20名受试者以配对实验设计分为实验组(利氧灵组)和对照组,每组10人。先在平原测量无氧阈(AT_(GE)),PWC_(170)和定量负荷运动心率(HR)。而后,乘飞机到达海拔4370m高原,重复上述指标的测量。结果表明,在该高度上停留一周时间里,两组的AT_(GE)、PWC_(170)明显低于平原对照值,HR明显高于平原对照值。但在同一时间里,实验组的上述指标明显好于对照组,如第5天,实验组的TI_(GE)、PWC_(170)和HR分别为529.2kg·m/min,1216.4kg·m/min和160b/min;对照组分别为362.6kg·m/min(P<0.05),1016.1kg·m/min(P<0.05)和170b/min(P<0.05)。可见,利氧灵对提高人体高原劳动能力有一定作用。     

提高高原劳动能力方案效果的评估研究

将９９名生活在海拔３６８０ｍ高原１年以上的健康男性受试者随机分为三组，分别接受锻炼（Ａ）、口服中成药（Ｂ）、以及既服中成药又锻炼（Ｃ）三种不同方案处理，以自身对照的方法测量其接受处理前后的体能指标和心血管指标。结果显示，接受处理后，其体能明显增强，并且循环系统指标的变化显示了其心脏功能和微循环的改善。研究结果还表明，Ａ、Ｂ、Ｃ三种方案均能改善体循环以抵抗缺氧，增强劳动能力。     

基质金属蛋白酶在慢性低氧高二氧化碳大鼠肺血管重建中的作用

目的 :研究基质金属蛋白酶在低氧高二氧化碳大鼠肺血管重建中的作用。方法 :将SD大鼠分为正常对照组 (C组 ) ,3w低氧高二氧化碳组 (H组 )。采用光镜、图像分析、免疫杂交等方法 ,观察各组大鼠肺动脉平均压 (mPAP)、颈动脉平均压 (mCAP)、右心室 / (左心室 室间隔 )重量比RV/ (LV S)、肺细小动脉显微结构、肺组织羟脯氨酸含量及明胶酶A、B(MMP 2、MMP 9)的表达变化。结果 :①H组mPAP、RV/LV S显著高于C组 (P <0 .0 1)。②肺组织匀浆羟脯氨酸含量H组显著高于C组 (P <0 .0 1)。③光镜下肺细小动脉管壁面积 /管总面积 (WA/TA)、管腔面积 /管总面积 (EA/TA)、肺细小动脉中膜厚度 (PAMT)C组明显低于H组 (P <0 .0 1)。④免疫杂交法检查发现肺组织匀浆MMP 2、MMP 9含量H组较C组显著升高 (P <0 .0 1)。结论 :低氧高二氧化碳促使基质金属蛋白酶表达升高 ,提示金属蛋白酶参与了肺血管重建     

肉苁蓉总苷对小鼠脑缺氧的保护作用

目的：研究肉苁蓉总苷(GCs)对小鼠脑缺氧的影响。方法：利用亚硝酸钠和氰化钾造成急性脑缺氧模型，观察GCs(62．5、125、250mg／kg)的抗缺氧作用，并测量氰化钾引起的脑缺氧小鼠脑组织内脂质过氧化产物——丙二醛(MDA)含量及自由基清除酶SOD的活性。结果：GCs能明显对抗小鼠脑缺氧，降低脑缺氧小鼠脑组织中MDA的含量，增加SOD的活性。结论：GCs对小鼠脑缺氧有一定的保护作用，可能与其增强自由基清除酶活性和对抗脂质过氧化的作用有关。