全脑低灌时脑的乳酸,乳酸脱氢酶,磷酸肌酸激酶的变化及对？…

目的和方法：阻断小鼠一侧颈总动脉和对侧椎动脉（２Ａ）,余剩供脑血藉Ｗillis氏环重 配以模拟近似全脑低灌（brain hypoperfusion,ＢＨ）。在全身动脉血压正常情况下研究其意义。结果：在两动脉低灌（ＢＨ－２Ａ）时,脑静脉血乳酸相对恒定,脑组织乳酸脱氢酶（ＬＤＨ）不变,磷酸肌酸激酶（ＣＰＫ）降低,外周血乳酸降低,血糖正常。不变的血糖可在ＢＨ－３Ａ时升高,认为上述变化是ＢＨ－２Ａ抑制所致,血粮从不变到升高是锐抑制     

小鼠脑低血流灌注缓解随后失血性休克所致变化

将小鼠一侧总动脉和对侧椎动脉阻断（ＢＨＩ－２Ａ）剩余脑血供藉ｗｉｌｌｉｓ环进行重分配以模拟近似失血性休克（ＨＳ）的全脑低灌，分析在ＨＳ过程中的意义。ＢＨＩ－２Ａ和ＨＳ组脑静脉血乳酸变量均无明显变化。ＨＳ组的外周血乳酸和血糖均明显升高。二者均可被６５４－２所预防；ＢＨＩ－２Ａ的外周血乳酸明显降低而血糖变化不明显，降低的乳酸也可被预先应用６５４－２所防止。ＢＨＩ－２Ａ３０ｍｉｎ＋ＨＳ组乳酸和血糖仍是Ｈ     

四逆汤抗犬急性心肌缺血的实验研究

目的：观察四逆汤对急性心肌缺血犬心内膜心电图及心肌酶学脂质过氧化损伤等指标的影响。方法：应用结扎犬冠状动脉的方法造成急性缺血模型,描记心电图,检测磷酸肌酸激酶（ＣＰＫ）,磷酸肌酸激酶同功酶（ＣＰＫ－ＭＢ）,谷丙转氨酶（ＡＬＴ）,乳酸脱氢酶（ＬＤＨ）,超氧化物歧化酶（ＳＯＤ）、丙二醛（ＭＤＡ）等指标。结果：四逆汤能显著降低急性心肌缺血犬 心电图缺血范围和缺血程度,降低血ＣＰＫ,ＣＰＫ－ＭＢ,ＬＤＨ等     

高胆固醇血症大鼠LDL受体与apoA－1mRNA的水平变化及苯甲酸雌二醇对其影响

本文研究了实验性高胆固醇血症大鼠肝及小肠中低密度脂蛋白（ＬＤＬ）受体ｍＲＮＡ和载脂蛋白（ａｐｏ）Ａ－１ｍＲＮＡ的水平变化以及苯甲酸雌二醇（ＥＢ）对二者的影响。发现高脂（ＨＣ）组肝及小肠ＬＤＬ受体ｍＲＮＡ水平分别低于正常组５０％和６０％（Ｐ＜０．０５），小肠ａｐｏＡ－１ｍＲＮＡ水平低于正常组５８％（Ｐ＜０．０５），此时血清总胆固醇（ＴＣ）及ＬＤＬ胆固醇（ＬＤＬ－ｃ）均明显高于正常组（Ｐ＜０．０１），血清ａｐｏＡ－１低于正常组（Ｐ＜０．０５）。ＨＣ＋ＥＢ组血清ＴＣ及ＬＤＬ－ｃ明显低于ＨＣ组，而肝ＬＤＬ受体ｍＲＮＡ水平则显著高于ＨＣ组，为ＨＣ组的３．５倍（Ｐ＜０．００２）。结果提示：（１）高胆固醇负荷时细胞可通过转录水平下行调节ＬＤＬ受体；（２）小肠可能在ａｐｏＡ－１的代谢中起重要作用；（３）ＥＢ可能通过诱导肝ＬＤＬ受体基因表达而降血脂。     

SRBC膜提取物对猪PBMNC第二信使的影响

胰酶水解绵羊红细胞（ＳＲＢＣ）释放膜表面活性蛋白组分Ⅲ（ＴＲＦ－Ⅲ），单独作用可使猪外周血单个核细胞（ＰＢＭＮＣ）胞内ｃＡＭＰ水平升高，以１００μｇ／ｍｌ浓度刺激达最高峰，由对照组０．９４±０．１４ｐｍｏｌ／Ｌ升高到２．７５±０．２５ｐｍｏｌ／Ｌ（Ｐ＜０．０１）。如果ＰＢＭＮＣ事先与腺苷酸环化酶（ＡＣａｓｅ）抑制剂ＬｉC１孵育后再以ＴＲＦ－Ⅲ或ＰＡＨ刺激。ｃＡＭＰ增高受到抑制（Ｐ＜０．０１）；而ＥＤＴＡ－２Ｎａ（一种磷酸二酯酶ＰＤＥ抑制剂）对此ｃＡＭＰ升高无影响。结果提示，此ｃＡＭＰ升高主要是通过活化ＡＣａｓｅ水解ＡＴＰ生成ｃＡＭＰ，而不像是抑制ＰＤＥ减少ｃＡＭＰ降解引起的。ＴＲＦ－Ⅲ诱导猪ＰＢＭＮＣ胞内Ｃａ~(２＋)浓度升高，以１００μｇ／ｍｌ刺激２分钟升高最多，由对照组的２４２±７ｎｍｏｌ／Ｌ升高到３２３±１５ｎｍｏｌ／Ｌ（Ｐ＜０．０１）。以ＥＧ－ＴＡ除去胞外Ｃａ~(２＋)再以ＴＲＦ－Ⅲ或ＰＡＨ刺激，仅观察到小范围［Ｃａ~(２＋)］ｉ升高。看来这一过程包括了刺激胞内Ｃａ~(２＋)释放和胞外Ｃａ~(２＋)内流两种方式。以上结果证明，ＴＲＦ－Ⅲ对淋巴细胞功能影响与细胞内第二信使有关。     

去甲肾上腺素影响单核细胞抗原提呈的机制

１０＾－１３～１０＾－９ｍｏｌ／Ｌ的去甲肾上腺素体外作用时能促进人外周血单核细胞的抗原提呈功能（ＡＰＦ）。ＰＫＣ激活剂ＰＭＡ和抑制剂４ａ－ＰＤＤ分别能加强和抑制ＮＥ对Ｍｏｎ的ＡＰＦ的促进作用；异搏定能抑制ＮＥ的这种作用，而ＰＫＡ的抑制剂ＰＫＩ对ＮＥ的这种作用无。结果提示ＮＥ促进ＭｏｎＡＰＦ的机制可能涉及到Ｃａ＾２＋和ＰＫＣ，而与ＰＫＡ无关。     

花生四烯酸产物对系膜细胞增殖作用的研究

用［３Ｈ］胸腺嘧啶核甙（［３Ｈ－ｔｈｙｍｉｄｉｎｅ，［３Ｈ］－ＴｄＲ）掺入法测定花生四烯酸产物对体外培养的大鼠肾小球系膜细胞的增殖作用。前列腺素Ｅ２（ｐｒｏｓｔａｇｌａｎｄｉｎ，ＰＧ）抑制血清所致的系膜细胞增殖。血栓素Ａ２（ｔｈｒｏｍｂｏｘａｎｅ，Ｔｘ）类似物Ｕ４６６１９、白三烯（ｌｅｕｋｏｔｕｉｅｎｅ，ＬＴ）Ｃ４、ＬＴＤ、１２－羟二十碳四烯酸（１２－ｈｙｄｒｏｘｙｅｉｃｏｓａｔｅｔｒａｅｎｏｉｃａｃｉｄ，１２－ＨＥＴＥ）、１５－ＨＥＴＥ促进静息的系膜细胞增殖，ＬＴＢ４及５－ＨＥＴＥ无此作用。用特异性蛋白激酶Ｃ（ｐｒｏｔｅｉｎｋｉｎａｓｅＣ，ＰＫｃ）抑制剂可抑制Ｕ４６６１９、ＬＴＣ４、ＬＴＤ４及１２－ＨＥＴＥ的促增殖作用。ＰＧＦ２α、Ｕ４６６１９、ＬＴＣ４、ＬＴＤ４促进系膜细胞合成二脂酰甘油（ｄｉａｃｙｌｇｌｙｃｅｒｏｌ，ＤＡＧ）。ＰＧＦ２α及ＬＴＤ４刺激系膜细胞合成三磷酸肌醇（ｉｎｏｓｉｔｏｌｔｒｉｐｈｏｓｐｈａｔｅ，ＩＰ３）。提示部分花生四烯酸产物活化ＰＫＣ而促进系膜细胞增殖。     

抗CD28＋B7.1单抗共刺激PBLs诱导肝癌细胞凋亡的蛋白激酶信号转导

目的 研究Ｔ淋巴细胞活化、增殖、介导肝癌细胞凋亡过程中其蛋白激酶Ｃ（ＰＫＣ）和酪氨酸蛋白激酶（ＴＰＫ）的活性变化。方法 用抗ＣＤ２８＋Ｂ７．１（ＣＤ８０）单克隆抗体共刺激正常人外周血淋巴细胞（ＰＢＬｓ）后作用于肝癌细胞（ＢＥＬ－７４０２）。结果 激活的Ｔ细胞中ＰＫＣ、ＴＰＫ活性明显增强,并与肝癌细胞凋亡程度呈正相关。结论 ＰＫＣ、ＴＰＫ在Ｔ细胞活化、增殖及诱导肝癌细胞凋亡的信号转导中起重要作用。     

A NEW ANALYTICAL METHOD FOR O_2 AND CO_2 TRANSFER IN SHELL-AND-TUBE(INTRA-LUMINALFLOW)OXYGEN AT ORS

ＡＮＥＷＡＮＡＬＹＴＩＣＡＬＭＥＴＨＯＤＦＯＲＯ２ＡＮＤＣＯ２ＴＲＡＮＳＦＥＲＩＮＳＨＥＬＬ－ＡＮＤ－ＴＵＢＥ（ＩＮＴＲＡ－ＬＵＭＩＮＡＬＦＬＯＷ）ＯＸＹＧＥＮＡＴＯＲＳＡＮＥＷＡＮＡＬＹＴＩＣＡＬＭＥＴＨＯＤＦＯＲＯ２ＡＮＤＣＯ２ＴＲＡＮＳＦＥＲＩ...     

小鼠内毒素休克某些血液变化和细胞超微结构损伤的发生

小鼠内毒素休克有血液的乳酸、ＮＰＮ、ＡＫＰ、ＬＤＨ水平升高和ｐＨ值降低并可用６５４－２或ＡＬ所预防，只是预防ＮＰＮ升高的效应须在早期的肾血管挛缩消失后才能显示出来；心、肝、肠和肺的ＭＤＡ含量升高并可被６５４－２预防，除肺外还可被ＡＬ预防；将高肺ＭＤＡ只能用６５４－２预防结合注射内毒素后１０ｍｉｎ有ＷＢＣ入肺扣押来看，损伤肺的自由萁坷能主要来自被激活的中性粒细胞；血中ＡＫＰ和ＬＤＨ升高分别反映溶酶体     

Involvement of brain lactate in neuronal metabolism

The involvement of brain lactate in neuronal metabolism was analyzed by ex vivo NMR spectroscopy with rats under the effects of pentobarbital, alphachloralose or morphine, which were infused with a solution of either [1-(13)C]glucose+lactate or glucose+[3-(13)C]lactate for 20 min. Electroencephalogram recordings indicated different brain electrical activity levels under the three drugs with a clear distinction between pentobarbital, on the one hand, and alphachloralose and morphine on the other. Labeling of metabolites in brain perchloric acid extracts and of blood glucose and lactate was determined by (13)C- and/or (1)H-observed/(13)C-edited-NMR spectroscopy. The following were found: (i) the ratio between glutamate C3 and C4 (13)C-enrichments increased from pentobarbital to alphachloralose and morphine whatever the labeled precursor, indicating a link between metabolic and electrical activity; (ii) under glucose+[3-(13)C]lactate infusion, alanine C3 and acetyl-CoA C2 enrichments were higher than that of lactate C3, revealing the occurrence of an isotopic dilution of the brain exogenous lactate (arising from blood) by lactate from brain (endogenous lactate); the latter was synthesized from glycolysis in a compartment other than the neurons; (iii) the contributions of labeled glucose and lactate to acetyl-CoA C2 enrichment indicated that the involvement of blood glucose relative to that of blood lactate to brain metabolism was correlated with brain activity. It can therefore be concluded that the brain electrical activity-dependent increase in the contribution of blood glucose relative to that of blood lactate to brain metabolism occurred partly via the increase in the metabolism of lactate generated from astrocytic glycolysis. This conclusion supports the hypothesis of an astrocyte-neuron lactate shuttle component in the coupling mechanism between cerebral activity and energy metabolism.     

血糖改变时兔脑细胞外液与血液中葡萄糖及乳酸变化的差异

目的：观察不同血糖条件下兔脑细胞外液与血液中葡萄糖（Glu）及乳酸（Lac）含量变化的差异。 方法： 采用微透析技术，每10 min收集脑细胞外液并静脉采血1次，观察正常条件下，以及静注20% Glu 0-60 min、胰岛素0-70 min期间血液及脑细胞外液中Glu及Lac的动态变化。 结果： 正常状态下，脑细胞外液中Glu明显低于血液，仅为血浆的30%，而Lac却显著高于血液，为血浆的165%；在高血糖及低血糖期间，脑细胞外液中Glu随着血糖浓度的改变而变化，但时间较血糖延迟30 min左右；脑细胞外液中Glu波动期间，Lac的水平无明显变化。 结论： 脑细胞外液中Glu及Lac水平与血液有很大差异，Lac可能参与了中枢神经系统的能量代谢。     

Effects of carbon dioxide,bicarbonate and pH on lactate and pyruvate in the brain of rats

Summary The influence of acute changes inPa _{CO 2}on lactate concentration in brain and blood was studied in hypercapnic and hypocapnic rats. Lactate in brain increases markedly whenP _{CO 2}is acutely decreased by severe hyperventilation. Compared with the observations in normal rats, the lactate response to an intense hypocapnia was decreased in animals maintained 24 hours in hypoxic alkalosis and increased after 24 hours hypercapnia. The results are discussed in relation to the hypothesis that the lactate concentration response in brain in these conditions is related to local pH. Incubation studies of brain tissue, in whichP _{CO 2}or (and) [HCO₃ ^–] were varied, show that lactate and pyruvate concentration and glucose consumption increase while the lactate/pyruvate ratio decreases when the pH of the incubation fluid is augmented. In an iso-pH system, lactate and pyruvate concentration, glucose consumption and L/P ratio increase with increasing [HCO₃ ^–]. The possible mechanisms and the possible importance of these metabolic variations are discussed.     

Whole-blood glucose and lactate. Trilayer biosensors, drug interference, metabolism, and practice guidelines

OBJECTIVE: To assess the effects of 30 of the most commonly used critical care drugs on measurements obtained with trilayer electrochemical biosensors on a reference analyzer (ABL625-GL), to determine metabolic changes in glucose and lactate in vitro, and to formulate guidelines for whole-blood analysis of these 2 analytes. DESIGN: Serial measurements were taken of changes in glucose and lactate levels caused by metabolism in whole blood in vitro over time. A parallel control study of drug interference with measurements of glucose and lactate in whole blood and of dose-response relationships in whole-blood samples and in plasma samples also was conducted. RESULTS: At room temperature, whole-blood metabolism decreased glucose levels -2.3% at 15 minutes, -4.6% at 30 minutes, and -6.4% at 45 minutes. Metabolism increased lactate levels 11.4% at 15 minutes, 20.6% at 30 minutes, and 26.7% at 45 minutes in vitro. Paired differences between drug-spiked and control samples were calculated to determine interference (corrected for metabolism). The threshold for determination of interference was +/-2 SD from within-day precision, equal to +/-0.18 and +/-0.10 mmol/L for glucose and lactate, respectively. Only mannitol (C(6)H(14)O(6)) interfered with glucose and lactate measurements. At a concentration of 24 mg/mL, mannitol decreased whole-blood glucose levels by an average of 0.711 mmol/L (12.8 mg/dL) and whole-blood lactate levels by 0.16 mmol/L (1.4 mg/dL). Mannitol interference with measurements may have resulted from suppression of hydrogen peroxide formation in the enzymatic reactions in the biosensors, repartitioning of water between erythrocytes and plasma, or from other mechanisms. CONCLUSIONS: Most critical care drugs had no significant effects on the trilayer electrochemical biosensors. Whole-blood analysis should be performed within 15 minutes for lactate and within 30 minutes for glucose because of metabolism in vitro. Mannitol effects on glucose measurements may be clinically significant in mannitol-induced acute renal failure and therefore should be considered for appropriate diagnosis and treatment of critically ill patients.     

Role of lactate in the brain energy metabolism: revealed by Bioradiography

To elucidate the role of lactate in the brain, we used a novel method, 'Bioradiography', in which the dynamic process could be followed in living slices by use of positron-emitter-labeled compounds and imaging plates. We studied the incorporation of 2-[18F]fluoro-2-deoxy-D-glucose ([18F]FDG) into rat brain slices incubated in oxygenated Krebs-Ringer solution. Under the glucose-free condition, [18F]FDG uptake rate in the cerebral cortex decreased with time and plateaued within 350 min but the addition of 5 mM lactate made the [18F]FDG uptake linear. When an inhibitor of the lactate transporter, 0.5 mM alpha-cyano-4-hydroxycinnamate (4-CIN) was applied to the glucose-free solution, the uptake rate decreased. Under the normal glucose condition, [18F]FDG uptake linearly increased for 6 h, but when 10 mM lactate was applied, the uptake rate decreased. In contrast, when 0.5 mM 4-CIN was applied to the normal glucose solution, [18F]FDG uptake rate increased. These results suggest that exogenous and endogenous lactate can substitute for glucose in the brain.     

Production of panic-like symptoms by lactate is associated with increased neural firing and oxidation of brain redox in the rat hippocampus

Lactate uses an unknown mechanism to induce panic attacks in people and panic-like symptoms in rodents. We tested whether intraperitoneal (IP) lactate injections act peripherally or centrally to induce panic-like symptoms in rats by examining whether IP lactate directly affects the CNS. In Long-Evans rats, IP lactate (2 mmol/kg) injection increased lactate levels in the plasma and the cerebrospinal fluid. IP lactate also induced tachycardia and behavioral freezing suggesting the production of panic-like behavior. To enter intermediate metabolism, lactate is oxidized by lactate dehydrogenase (LDH) to pyruvate with co-reduction of NAD⁺ to NADH. Therefore, we measured the ratio of NADH/NAD⁺ to test whether IP lactate altered lactate metabolism in the CNS. Lactate metabolism was studied in the hippocampus, a brain region believed to contribute to panic-like symptoms. IP lactate injection lowered the ratio of NADH/NAD⁺ without altering the total amount of NADH and NAD⁺ suggesting oxidation of hippocampal redox state. Lactate oxidized hippocampal redox since intrahippocampal injection of the LDH inhibitor, oxamate (50 mM) prevented the oxidation of NADH/NAD⁺ by IP lactate. In addition to oxidizing hippocampal redox, IP lactate rapidly increased the firing rate of hippocampal neurons. Similar IP pyruvate injections had no effect. Neural discharge also increased following intrahippocampal lactate injection suggesting that increased discharge was a direct action of lactate on the hippocampus. These studies show that oxidation of brain redox and increased hippocampal firing are direct actions of lactate on the CNS that may contribute to the production of lactate-induced panic.     

Actomyosin ATPase, myokinase, CPK and LDH in human fast and slow twitch muscle fibres.

The enzyme activities of Mg2+ stimulated ATPase, creatine phosphokinase (CPK), myokinase (MK) and lactate dehydrogenase (LDH) were determined in pooled fast twitch (FT) and slow twitch (ST) human skeletal muscle fibers, dissected out from freeze-dried muscle biopsy material. All enzymes investigated demonstrated higher activities in FT fibres. The ratio in enzyme activity between fibre types was greatest for Mg2+ stimulated ATPase (3:1) and smallest for CPK (1.3:1). In addition, the isozyme patterns of CPK, MK and LDH were studied by means of isoelectric focusing (CPK and MK) and discelectrophoresis (LDH). A difference was observed between fibre types with respect to the isozyme distribution of MK and LDH, whereas the CPK isozyme pattern was similar in both fibre types. These results on separated human FT and ST fibres were essentially in conformity with what has earlier been indicated from experiments on mixed muscle homogenates.     

小鼠创伤性休克时血中糖,乳酸和NPN变化的发生

小鼠创伤性休克时血中糖，乳酸和ＮＰＮ升高。休克９０ｍｉｎ血糖开始回降，１２０ｍｉｎ骤降而成为死亡的先兆。６５４－２和ＡＬ可预防高乳酸血，对高氮质血无效，因为过多的含氮物主要来自破坏的组织而非代谢障碍。６５４－２可使高血糖曲线右移，延长存活时间，ＡＬ无此作用。除肾外，心，肝，肺均有ＭＤＡ升高；６５４－２可预防心，肝的ＭＤＡ升高而对肺无效；ＡＬ可预防肺，肝ＭＤＡ升高而对心无效；提示不同器官的自由基来源     

实验性急性呼吸窘迫综合征大鼠脑组织Gq蛋白-肌醇磷脂途径的变化

目的：探讨急性呼吸窘迫综合征（ARDS）大鼠脑组织中Gq蛋白-肌醇磷脂途径的变化及其作用。方法：健康雄性40只 Wistar 大鼠随机分为油酸组（OA组）和对照组。OA组由大鼠尾静脉注射OA 0.2 mL/kg （2 min内）复制ARDS模型，根据不同观测时点分为30 min、60 min、90 min和120 min 4个亚组。检测各组大鼠平均动脉血压（MABP），血气，血浆和脑组织丙二醛含量及乳酸脱氢酶（LDH）、肌酸激酶（CK）活性。免疫印迹法检测各组大鼠脑组织中的Gq/11蛋白α活性亚基以及磷脂酶C （PLC）含量。结果：与对照组相比，OA组MABP、PaO2明显降低（P<0.05）。OA 90 min和120 min组血浆和脑组织的MDA含量和LDH活性明显升高（P<0.05）。OA组血浆CK活性较对照组明显升高（P<0.05），脑组织CK活性在OA 60 min组升高（P<0.05），随后在90 min和120 min组降低（P<0.05）。脑组织Gαq/11蛋白在OA 60 min、90 min和120 min组明显升高（P<0.05）。OA组脑组织PLC表达明显上调（P<0.05）。脑组织Gαq/11蛋白表达与PaO2 的改变呈负相关（r=-0.579，P<0.05），与脑组织MDA变化呈正相关（r=0.538，P<0.05），与脑组织LDH的变化亦呈正相关（r=0.624，P<0.05）。结论：ARDS时Gq蛋白-肌醇磷脂信号通路活性增强可能参与了脑组织的损伤。