ATP敏感性钾通道与心肌低氧损伤

ATP敏感性钾通道是一种受细胞内ATP浓度，NDPs，KCOs,SUs等多种因素调节启闭的钾通道。在低氧条件下，ATP敏感性钾通道被激活，引起动作电位时程缩短和细胞外钾离子蓄积，减少钙离子内流，对心肌有一定的保护作用；但过度的钾离子外流，对心肌则有损害，甚于诱发心律失常。提示：ATP敏感性钾通道的开放，可能是低氧引起心肌损伤的一种内源性机制。     

NMR Study of Damage on Isolated Perfused Rat Heart Exposed to Ischemia and Hypoxia

IntroductionMyocardial ischemia is the most common andprimary cause of myocardium damage. A rapidrestoration of the heartblood supply after injury isvery important for retaining its function.However,after a certain period of time,resumingthe blood supply may aggravate the damage to thecardiac muscle. Therefore,the mechanisms ofmyocardial ischemia and reperfusion damage mustbe studied to provide important data to reduce orprevent reperfusion damage in clinical treatmentofischemic heart diseases…     

Muscle lipofuscin content and satellite cell volume is increased after high altitude exposure in humans

Summary Muscle ultrastructural changes during a typical expedition to the Himalayas were analyzed by taking muscle biopsies from seven climbers before and after their sojourn at high altitude (over 5000 m for 8 weeks). M. vastus lateralis samples were analyzed morphometrically from electron micrographs. A quantitative evaluation was made of lipofuscin, satellite cells and myonuclei. Significant increases of the volume densities of lipofuscin (+235%) and satellite cells (+215%) were observed.     

温度对中华倒刺鲃静止代谢及低氧耐受的影响

为考查温度对鱼类静止代谢率及低氧耐受能力的影响,本研究以中华倒刺鲃（Spinibarbus sinensis）幼鱼为对象,分别在10、20和30℃条件下驯化2周,随后将实验鱼置于密闭呼吸室中测定静止代谢率,并通过“双线法”推出临界氧压（Pcrit）等相关参数。实验结果显示：随着温度的上升,中华倒刺鲃幼鱼静止代谢率（MO2rest）、Pcrit点所对应代谢率（MO2pcrit）以及临界代谢范围（MMS）均显著上升（p〈0.05）;MO2rest的温度系数（Q10）在10-20 ℃和20-30 ℃间分别为2.54和1.27。而中华倒刺鲃幼鱼Pcrit却不受温度变化的显著影响,表现出一定的保守性。研究表明,中华倒刺鲃幼鱼Pcrit随温度的变化趋势并不与 MO2rest的变化趋势相吻合,这提示随温度的改变中华倒刺鲃可能还启用了其他生理、生化和（或）行为学机制。     

缺氧预适应小鼠脑匀浆提取液对Hep G2细胞缺氧耐受性的影响

目的:探讨缺氧预适应小鼠脑匀浆提取液(HP)对Hep G2细胞缺氧耐受性的影响.方法:用4种浓度的HP作用于缺氧(2%O2)培养HepG2细胞,以同浓度正常小鼠脑匀浆提取液(NP)作对照,检测了在缺氧培养后,Hep G2细胞的MTT值、早期凋亡率(Annexin V-FITC/PI双染流式细胞仪检测)、晚期凋亡率(Hoechst33258染色荧光显微镜检测).结果:低浓度HP对Hep G2细胞有保护作用,而高浓度HP对Hep G2细胞有损伤作用.结论:HP的作用有浓度依赖性和时间依赖性.     

大脑皮质微血管内皮细胞培养及其缺氧性损害模型

建立改良的体外培养大鼠脑皮质微血管内皮细胞缺氧模型．取1～5d Wistar乳鼠脑皮质获得的脑微血管内皮细胞（BMEC）进行体外培养，缺氧组置入一个经改造的保鲜盒内，密闭并通入混合气体（95％N2和5％CO2）12h，检测缺氧细胞的形态结构、细胞死亡率及培养液中乳酸脱氢酶漏出量．结果显示缺氧BMEC形态结构损伤，细胞死亡率增加，细胞乳酸脱氢酶漏出量显著增加（p〈0．01）．该模型可使脑血管内皮细胞受到损伤，证实该模型具有一定的可靠性、操作简便，可重复性强，为体外研究脑血管疾病提供帮助．     

三七丹参与慢性缺氧小鼠 POD 及酪氨酸酶活性

慢性缺氧引起小鼠心、脑和血液等组织过氧化物酶（ＰＯＤ）与心脑酪氨酸酶活性增加，引起血液酪氨酸酶活性减少．三七与丹参提高组织酪氨酸酶活性并降低脑组织和血液ＰＯＤ活性．缺氧时三七对血液ＰＯＤ和脑组织酪氨酸酶的作用被显著增强，丹参则表现为对脑ＰＯＤ及对心血酪氨酸酶活性的作用被显著增强．     

Is there a critical tissue oxygen tension for bioenergetic status and cellular pH regulation in solid tumors?

Bioenergetic and metabolic status have been correlated with tissue oxygenation in murine fibrosarcomas (FSaII) of varying sizes (44–600 mm³). Ratios of -nucleoside triphosphates to inorganic phosphate (NTP/P_i) and phosphocreatine to inorganic phosphate (PCr/P_i) ratios derived from³¹P nuclear magnetic resonance spectroscopy (NMR) were positively correlated to median tissue O₂ tension (pO₂) values using O₂-sensitive needle electrodes. pH declined during growth with intracellular acidosis being evident in tumors >350 mm³. Whereas lactic acid formation greatly contributed to this decline in small and medium-sized tumors, adenosine triphosphate (ATP) hydrolysis and slowing down of the activities of pumps involved in cellular pH regulation seem to be major factors responsible for intracellular acidification in bulky tumors. PCr levels decreased at an early growth stage, whilst ATP concentrations dropped in bulky malignancies only, coinciding with a decrease in adenylate energy charge and a substantial rise in the levels of total P_i On average, median pO₂ values of ca. 10 mmHg represent a critical threshold for energy metabolism. At higher median O₂ tensions, levels of ATP, phosphomonoester (PME) and total P_i were relatively constant. This coincided with intracellular alkalosis or neutrality and stable adenylate ratios. On average, median pO₂ values <10 mmHg coincided with intracellular acidosis, ATP depletion, a drop in energy charge and rising P_i levels.     

刺猬、黄鼠和大白鼠对阶梯式低压缺氧耐受性的比较

本实验以体温、心率和呼吸频率为指标观察刺猬、黄鼠和大白鼠三种动物在常温(20±2℃)中清醒状态下对阶梯式低压缺氧的反应。各组动物均为6例。在低压舱中模拟高空低压缺氧、在模拟高度4000米、5000米及6000米阶段各停留30分钟,7000米停留2小时。结果表明:对缺氧的耐受性以刺猬最强,黄鼠次之,大白鼠最差。此结果提示:冬眠动物可能比非冬眠动物对缺氧具更强的耐受性。     

缺氧对冬眠刺猬激醒作用的初步观察

本文首次报告刺猬在冬眠状态下对缺氧反应的初步观察结果。观察指标为体温,心率和呼吸频率。6只刺猬在低压舱内一个大气压和环温2±2℃的条件下进入冬眠状态后,由低压舱模拟高空阶梯式低压缺氧。在模拟高度4000米、5000米及6000米阶段各停留30分钟,7000米停留2小时。结果表明:缺氧对处于冬眠状态的刺猬有促进其激醒的作用。