急性颅脑损伤大鼠脑组织ATP酶活性及TNF-α的变化及意义

目的 观察大鼠急性颅脑损伤后脑组织ATP酶活性及肿瘤坏死因子-α（TNF-α）的变化,探讨急性颅脑损伤后脑水肿的发病机制.方法 将72只SD大鼠随机分为正常组（N组）、假手术对照组（S组）、急性颅脑损伤模型组（ACI组）,其中S组和ACI组于造模后分为2、6、24、72 h时间点,每个时间点8只大鼠;取大鼠伤灶区脑组织测定Na＋-K＋-ATP酶和Ca2＋-ATP酶活性、TNF-α含量及脑组织含水量.结果 急性颅脑损伤后脑组织Na＋-K＋-ATP酶、Ca2＋-ATP酶活性降低（P〈0.05）,TNF-α含量升高（P〈0.05）;颅脑损伤后24 h脑水肿较严重.相关性分析提示,Ca2＋-ATP酶活性与TNF-α含量呈负相关（P〈0.05）.结论 急性颅脑损伤后可引起脑组织ATP酶活性降低、TNF-α含量增加,两者可能协同参与了急性颅脑损伤后脑水肿.     

激光生物学技术研究高脂血症大鼠红细胞变形能力改变及其机制

目的:通过研究红细胞膜流动性以及红细胞骨架结构的改变,进一步探讨高脂血症大鼠红细胞变形能力改变的机制。方法:16只Wistar大鼠随机分为两组:高血症组和对照组。高脂组给予高脂饮食。16周后,腹主动脉采血,采用酶比色法检测血浆甘油三脂、胆固醇含量;并利用激光衍射法测定红细胞变形指数、取向指数,荧光偏振法测定红细胞膜流动性,激光共聚焦显微镜观测红细胞骨架改变和红细胞F-actin的含量。结果:发现高脂血症大鼠红细胞的变形指数、取向指数以及红细胞膜的流动性显著降低(P<0.05),红细胞形态和骨架发生改变,F-actin含量显著降低(P<0.05)。结论:高脂血症大鼠红细胞变形能力降低与红细胞膜结构改变有一定的关系。     

铝和铝+钙对小麦幼苗根尖质膜、液泡膜微囊ATP酶和膜流动性的影响

研究了铝和铝 钙对小麦幼苗根尖质膜、液泡膜微囊H ATP酶、Ca2 ATP酶、Mg2 ATP酶活性及其动力学参数和膜流动性的影响。在质膜和液泡膜微囊制剂中加入 1.0mmol/L的Al3 (AlCl3)时 ,H ATP酶、Ca2 ATP酶、Mg2 ATP酶活性和酶促反应的Vmax及膜流动性下降 ,而酶促反应的最适pH和Km 均不受影响。提高酶促反应介质的Ca2 (CaCl2 )浓度可以缓解Al3 对膜ATP酶活性和膜流动性的影响。推测Al3 可能通过与膜的结合而抑制膜ATP酶的活性     

大强度训练及恢复后大鼠红细胞变形能力和红细胞膜蛋白的变化

目的 :探讨运动对红细胞变形性和红细胞膜蛋白的影响及其相互关系。方法 :设计不同强度的训练方案 ,用激光衍射法测定红细胞变形能力 ,用SDS PAGE方法测定一定体积大鼠红细胞膜中的重要蛋白带 3蛋白 (band 3)和肌动蛋白 (actin)的含量 ,研究运动即刻和恢复后红细胞变形性及膜蛋白的变化。结果 :长期的运动训练会促进大鼠红细胞变形能力的改善和红细胞膜band 3蛋白和actin的良好发展 ,一次大强度训练会引起红细胞膜band 3蛋白和actin含量的减少 ,大鼠红细胞变形能力降低 ,一周和二周的大强度训练会提高恢复期大鼠红细胞的变形能力和红细胞膜band 3蛋白和actin含量。结论 :运动训练造成的红细胞膜蛋白含量的变化 ,导致了红细胞膜结构的改变 ,从而影响红细胞变形能力 ,可能是训练对红细胞变形能力的作用机制之一。     

栀子提取物ZG对副流感病毒1型感染后宿主细胞膜的影响

为了探讨栀子提取物ZG抗病毒作用的生物学机制,观察了栀子提取物ZG对副流感病毒1型(PIV-1)感染后宿主细胞膜电位、膜Na -K -ATP酶活性和膜流动性的影响。以氯化乙酰胆碱为阳性对照,采用荧光探针Di-BAC4(3)标记Hep-2细胞膜电位,借助流式细胞仪检测膜电位;定磷法,分光光度计检测Na -K -ATP酶活性;荧光探针NBD-C6-HPC标记细胞膜磷脂,以荧光漂白恢复法和激光扫描共聚焦显微镜检测膜流动性。结果显示:PIV-1感染后宿主细胞膜电位下降,处于超极化状态;膜Na -K -ATP酶活性显著增加,膜流动性显著降低。栀子提取物ZG作用后,对宿主细胞膜的超极化状态没有明显影响;对膜Na -K -ATP酶活性没有明显影响;而对膜流动性则有明显的恢复作用。阳性对照药乙酰胆碱能明显改善病毒感染后膜电位的超极化状态。PIV-1感染后膜电位、Na -K -ATP酶活性和膜流动性等细胞膜能态和功能的改变,可能为病毒感染的生物学机制之一;栀子提取物ZG可能是通过改善细胞膜流动性,维持细胞膜的正常功能来发挥抗病毒感染的作用,而与膜电位和膜Na -K -ATP酶活性等能态来源的环节可能无关。     

竹节参对力竭运动大鼠心肌线粒体ATP酶活性的影响

目的：探讨竹节参对力竭运动大鼠心肌线粒体ATP酶活性的影响。方法：建立力竭运动大鼠模型,测定心肌线粒体ATP酶的活性,研究竹节参对大强度耐力训练大鼠心肌线粒体的保护作用。结果：力竭运动引起大鼠心肌线粒体ATPase（Na＋,K＋-ATPase和Ca2＋-ATPase）活性显著下降,而运动加药组Ca2＋-ATPase有显著升高,Na＋,K＋-ATPase也有明显升高,且ATPase活性均接近于安静对照组的水平。结论：竹节参可提高力竭运动大鼠心肌线粒体内Na＋,K＋-ATP酶和Ca2＋-ATP酶的活性,提示其具有保护线粒体的作用。     

急性热应激对大鼠肺细胞膜磷脂代谢及膜流动性的影响

使用高效液相色谱法测定了正常健康雄性大鼠经急性热应激致肛温达42℃后,肺细胞膜中磷脂酰丝氨酸(PS),磷脂酰胆碱(PC)的变化,同时用荧光探剂标记红细胞和肺组织细胞膜制剂,采用偏振荧光法测定了膜流动性的改变。结果表明,正常大鼠的PS和PC分别为425.1±68.1μg/g湿重和53.5±9.7mg/g湿重,肛温达42℃持续15min时,两者明显减低,分别为224.3±51.3μg/g湿重和26.5±5.5mg/g湿重。热应激大鼠置于室温下恢复4h后,两者又都回到正常水平。热应激后,大鼠红细胞膜及肺组织细胞膜的流动性明显降低。表明膜磷脂含量的改变对膜流动性有明显的影响。     

严重烧伤早期红细胞膜胆固醇含量及Na+-K+-ATP酶活性的变化

目的 :研究严重烧伤患者早期红细胞滤过指数 (EFI)与红细胞膜胆固醇含量、Na K ATPase活性的变化。探讨其在严重烧伤早期中的相互关系及意义。方法 :采用核孔滤膜法测定红细胞滤过指数 (EFI) ,用化学修饰电极法测定红细胞膜胆固醇含量 ,应用定磷法测定红细胞膜Na K ATPase活性。结果 :4 7例严重烧伤早期患者EFI较 6 0例正常对照组下降 (P <0 .0 1) ,红细胞膜胆固醇含量、Na K ATPase活性均高于正常对照组 (P <0 .0 1) ,且红细胞膜胆固醇含量、Na K ATPase活性与EFI呈密切负相关 (rcho =- 0 .871,rATPase =- 0 .80 1,P <0 .0 1)。结论 :严重烧伤早期EFI下降 ,变形性明显减低是导致血液粘度和微循环改变的原因之一 ,红细胞膜胆固醇含量和Na K ATPase活性的变化则是引起EFI下降、变形性减低的重要因素     

高胆固醇血症血液流变性的研究

对实验性高胆固醇血症家兔血液流变性、红细胞流变性、红细胞膜脂分析以及与血清胆固醇浓度之间关系的研究指出随血清胆固醇浓度升高,全血表观粘度和血浆粘度升高,红细胞(?)积和(?)降低.进一步分析表明,随血清胆固醇浓度升高,红细胞膜中胆固醇Ch含量增加,引起膜胆固醇和磷脂(P1)的克分子比(Ch,P1)升高,膜的荧光偏振度(P)增大,表示红细胞流动性降低,而对照组各项指标在实验过程中保持稳定.     

低氧应激下甘肃鼢鼠与SD 大鼠心脏抗氧化酶和ATP 酶活性的比较

为探讨低氧应激下甘肃鼢鼠心脏对抗氧化损伤和电生理紊乱的可能机制,对甘肃鼢鼠和SD 大鼠在4. 5%氧浓度下分别进行2 h、4 h、6 h、8 h、10 h、16 h 低氧应激,比较常氧和各时程低氧下二者心脏超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、谷胱甘肽还原酶(GR)和Ca^{2 +} - ATP 酶、Ca^{2 +} - Mg^{2 +} - ATP 酶、Na ⁺ - K ⁺ - ATP酶活性,以丙二醛(MDA)含量作为机体氧化损伤指标。结果显示,常氧组甘肃鼢鼠GR 活性比SD 大鼠高,SOD、CAT、Ca^{2 +}-ATP 酶、Ca^{2 +} - Mg^{2 +} - ATP 酶和Na ⁺ - K ⁺ - ATP 酶活性及MDA 含量与SD 大鼠相比均无显著性差
异;低氧组甘肃鼢鼠SOD、CAT、GR、Ca^{2 +} - ATP 酶、Ca^{2 +} - Mg^{2 +} - ATP 酶和Na ⁺ - K ⁺ - ATP 酶活性迅速升高,显著高于SD 大鼠,MDA 含量则显著低于SD 大鼠。说明甘肃鼢鼠心脏通过提高抗氧化酶活性清除低氧诱导产生的多余自由基,并通过提高ATP 酶活性保证心电活动正常、心率稳定,应对低氧应激。     

Lipid translocation across the plasma membrane of mammalian cells.

The plasma membrane, which forms the physical barrier between the intra- and extracellular milieu, plays a pivotal role in the communication of cells with their environment. Exchanging metabolites, transferring signals and providing a platform for the assembly of multi-protein complexes are a few of the major functions of the plasma membrane, each of which requires participation of specific membrane proteins and/or lipids. It is therefore not surprising that the two leaflets of the membrane bilayer each have their specific lipid composition. Although membrane lipid asymmetry has been known for many years, the mechanisms for maintaining or regulating the transbilayer lipid distribution are still not completely understood. Three major players have been presented over the past years: (1) an inward-directed pump specific for phosphatidylserine and phosphatidylethanolamine, known as aminophospholipid translocase; (2) an outward-directed pump referred to as 'floppase' with little selectivity for the polar headgroup of the phospholipid, but whose actual participation in transport of endogenous lipids has not been well established; and (3) a lipid scramblase, which facilitates bi-directional migration across the bilayer of all phospholipid classes, independent of the polar headgroup. Whereas a concerted action of aminophospholipid translocase and floppase could, in principle, account for the maintenance of lipid asymmetry in quiescent cells, activation of the scramblase and concomitant inhibition of the aminophospholipid translocase causes a collapse of lipid asymmetry, manifested by exposure of phosphatidylserine on the cell surface. In this article, each of these transporters will be discussed, and their physiological importance will be illustrated by the Scott syndrome, a bleeding disorder caused by impaired lipid scrambling. Finally, phosphatidylserine exposure during apoptosis will be briefly discussed in relation to inhibition of translocase and simultaneous activation of scramblase.     

Transport ATPases in the erythrocytes of rats acclimatized to intermittent altitude hypoxia

The activity of Na+/K+- and Ca2+-ATPase and some allosteric properties of Na+/K+-ATPase were studied in whole erythrocytes and their membrane preparations (ghosts) from rats exposed to intermittent altitude hypoxia (10 and 24 exposures, 8 h/day in an altitude chamber, stepwise up to an altitude of 7,000 m). Ca2+-ATPase activity was increased both in whole erythrocytes and ghosts after the first phase of acclimatization (10 exposures). In a standard incubation medium (containing 3 mmol.l-1 MgCl2 ), Na+/K+-ATPase activity in the ghosts was also increased after the initial phase of acclimatization whereas in whole erythrocytes Na+/K+-ATPase was only decreased in the regression phase. At high MgCl2 concentrations (12 mmol.l-1) changes of Na+/K+-ATPase activity both in whole erythrocytes and in the ghosts followed similar time course with a pronounced increase in the first phase of acclimatization (10 exposures) followed by an abrupt drop (24 exposures) and then by a gradual normalization in the regression phase. Sensitivity of the enzyme to mounting MgCl2 concentrations was increased in the ghosts at the end of acclimatization and was decreased in whole erythrocytes during acclimatization and especially in the regression phase. It has been suggested that chronic altitude hypoxia leads to the alteration of cooperative interaction of the Na+/K+-ATPase subunits in the erythrocyte membrane and accumulation of some factor in the cells inhibiting this enzyme.     

Biochemical,biophysical and haemorheological effects of dimethylsulphoxide on human erythrocyte calcium loading

The studies using dimethylsulphoxide (DMSO) and/or the 4-bromo-calcium ionophore A23187 (Br-A23187) often neglect the precise knowledge of some of their biochemical, biophysical and haemorheological effects. The aim of the present study was to evaluate these effects on erythrocytes after whole blood incubations with DMSO or Br-A23187 dissolved in DMSO. There were no significant differences between the different aliquots in the values of P(50), pH, erythrocyte deformability, erythrocyte membrane fluidity, haemoglobin and intracellular Ca(2+) concentrations ([Ca(2+)](i)). Aliquots with DMSO (independently of the presence of Br-A23187 or added Ca(2+)) had lower erythrocyte aggregation indexes and higher plasma concentrations of K(+)], Na(+)] and Ca(2+) than the aliquots without DMSO (independently of the presence of added Ca(2+)). Aliquots with added calcium (without the presence of Br-A23187 in DMSO) had a significantly higher erythrocyte acetylcholinesterase activity. Our data shows that calcium loading, the usual objective of Br-A23187 incubations, cannot be fulfilled with the studied experimental conditions. The coherence between our results and those obtained by other authors with different biological systems and different modulators of the rise on [Ca(2+)](i) suggests a non-specific effect of DMSO, disabling the action of the modulator. It can be reasoned that the decreased erythrocyte aggregation (without significant changes on the deformability or membrane fluidity) can result either from the decrease of the hydrogen bonding contribution to erythrocyte aggregation or the increased ionic strength influence on the erythrocyte membrane surface.     

缺锌对大鼠红细胞膜生物物理性质的影响

利用激光衍射仪,荧光分光光度法,ＥＳＲ等牲物理技术和缺锌大鼠模型,研究缺锌对大鼠红细胞膜生物物理性质的影响,实验结果表明缺锌使大鼠红细胞的变形能力增大,稳定性降低,红细胞膜脂的流动性和膜蛋白的运动性增加,支持了锌具有维持膜结构和功能和生理作用的理论;为膜结构和功能的改变是缺锌病理变化主要原因的假说提供了实验依据。     

Stimulated nonspecific transport of phospholipids results in elevated external appearance of phosphatidylserine in ras-transformed fibroblasts

The content of phosphatidylserine (PS) was found to be increased three times in the plasma membrane outer leaflet of ras-transformed fibroblasts compared to their nontransformed counterparts. In an attempt to determine the mechanisms responsible for the enhanced external appearance of PS, we investigated the activities of aminophospholipid translocase and the nonspecific lipid scramblase. Both transport systems could separately or in combination contribute to PS accumulation in the extracellular leaflet. Aminophospholipid transfer was assessed by measuring the rate of NBD-PS internalization, and scramblase activity was estimated from the internalization of NBD-PC. The results showed that the aminophospholipid transport was inhibited and the nonspecific transport was stimulated in ras-transformed cells. To assess which of these two transport systems was related to elevation of PS external appearance, each of them was submitted to reversible alterations and the content of PS was measured simultaneously. Aminophospholipid translocase activity was inhibited by pyridyldithioethylamine treatment and reversed by reduction with dithiothreitol. Scramblase activity was modulated by a calcium repletion-depletion procedure. Calcium depletion was performed by cell incubation with BAPTA-AM and EGTA as Ca2+ intracellular and extracellular chelators. Restoration of the intracellular Ca2+ was achieved by cell incubation with Ca2+ and Ca2+-ionophore A23187. The results showed that the changes in PS outer appearance did not correlate with the uptake of NBD-PS but were closely related to NBD-PC internalization, suggesting that the nonspecific bidirectional lipid transfer was the major transport system translocating PS to the outer leaflet in ras-transformed cells.     

Electron spin resonance, hematological, and deformability studies of erythrocytes from patients with Huntington's disease.

Electron spin resonance, hematologic, and deformability studies of erythrocytes from patients with Huntington's disease have been performed A decreased deformability of Huntington's disease erythrocytes compared to normal controls was demonstrated. No difference in erythrocyte hematologic indices, osmotic fragility, reticulocyte counts, or intracellular Na+ concentration was found. Huntington's disease serum had no demonstrable effect on electron spin resonance parameters of a protein-specific spin label attached to membrane proteins in control erythrocytes compared to the effect of control serum. This finding suggests that under the conditions employed no serum component or circulating factor is responsible for the changes in the physical state of membrane proteins in Huntington's disease erythrocytes (Butterfield, D.A., Oeswein, J.Q. and Markesbery, W.R. (1977) Nature 267, 453--455). No alteration in lipid fluidity of Huntington's disease erythrocyte membranes could be discerned suggesting that the underlying molecular defect in Huntington's disease involves a membrane protein. The results of the present studies on erythrocytes strongly support the concept that Huntington's disease is associated with a generalized membrane abnormality.     

缺氧时大鼠红细胞变形性损伤的机制研究

本实验通过测定平原和模拟高原减压缺氧３０天大鼠红细胞滤过指数（ＩＦ）、红细胞内［ｐＨ］ｉ、［Ｋ＋］ｉ／［Ｎａ＋］ｉ比值、［Ｃａ２＋］ｉ、［Ｍｇ２＋］ｉ、平均红细胞体积（ＭＣＶ）及平均红细胞血红蛋白浓度（ＭＣＨＣ）,从而探讨缺氧条件下大鼠红细胞变形性损害的机制。结果发现：１．缺氧组大鼠红细胞［Ｃａ２＋］ｉ明显升高,且与ＩＦ呈显著正相关,但［Ｍｇ２＋］ｉ无明显差异;２．缺氧组［Ｋ＋］ｉ／［Ｎａ＋］ｉ值较平原组明显降低,且与ＩＦ呈显著负相关;３．缺氧组ＭＣＨＣ与平原组无明显差异,但ＭＣＶ显著升高;４．缺氧组红细胞内［ｐＨ］ｉ较平原组明显升高。提示：缺氧时红细胞［Ｃａ２＋］ｉ升高,［Ｋ＋］ｉ／［Ｎａ＋］ｉ值降低,ＭＣＶ增大以及红细胞［ｐＨ］ｉ值的改变在其变形性损伤中起重要作用。     

Damage to the structure of erythrocyte plasma membranes in patients with type-2 hypercholesterolemia

BACKGROUND: Hypercholesterolemia may decrease the deformability of red blood cells which impairs their hemorheological behavior and promotes atherosclerosis.The study involved 60 hypercholesterolemic patients and 30 healthy individuals as the control group.METHODS: The membrane fluidity of erythrocytes was estimated by a spin-label method (5-doxylstearic acid (5-DSA)). The ratio of weakly to strongly (W/S) immobilized residues of erythrocyte membrane-bond maleimide-tempo spin label was studied in oxidative damage to membrane protein. Damage to erythrocyte proteins was also indicated by means of Na(+) K(+) ATPase activity.RESULTS: The membranes of hyperlipidemia (hlp) patients contain larger concentrations of cholesterol 2.16+/-0.24 than do those of the normolipemic individuals 0.31+/-0.24 (P<0.001). The level of Na(+) K(+) ATPase in the erythrocyte membrane from the control group was higher 103.4+/-1.3 (nmolPi/(mgproteinsh)) than in the patient group 93.6+/-3.2 (nmolPi/(mgproteinsh)) (P<0.001). The order parameter S 5-DSA in the control group was 0.745+/-0.009 and in hlp patients was 0.755+/-0.009 (P<0.001). The W/S ratio in the control group amounted to 2.00+/-0.09 and in the hlp patient group was 2.50+/-0.11 (P<0.001).CONCLUSION: Type-2 hypercholesterolemia causes changes in the structure and fluidity of erythrocyte plasma membranes since the excess of cholesterol affects the normal rheology of blood through its interaction with erythrocytes. It also impairs the function and structure of plasma membrane proteins.     

Erythrocyte membrane fluidity and changes in plasma lipid composition: a possible relationship in childhood obesity

We have studied plasma lipid patterns and erythrocyte membrane fluidity in 60 obese children and 20 normal children. Plasma levels of total cholesterol and associated low-density lipoproteins were significantly increased in 20 obese patients with respect to controls. A significant decrease in membrane fluidity, measured as an increase in the fluorescence polarization value of the probe 1,6-diphenyl-1,3,5-hexatriene, associated with an increase in the cholesterol/protein ratio has been shown in obese patients. The study of the correlation between erythrocyte membrane fluidity and plasma cholesterol has indicated that significant changes in fluidity and membrane lipid composition also occur in erythrocytes of obese patients with normal plasma lipid levels. These findings confirm that the erythrocyte membrane responds very early to modifications of plasma lipoproteins and suggest that in childhood obesity a modified transfer of cholesterol from plasma to erythrocyte membrane may take place.