Ion Gradients And Metabolic Energy In Animal Tissue

工作灌注心脏中九种主要无机离子的梯度能量彼此接近平衡，胞外和胞内相之间的电势和ATP水解的DG接近平衡（增田T等，J Biol Chem 1990;265：20321-34）。乙醇的代谢将肝细胞的静息电位从28 mV增加到40 mV（Veech RL等人，Alcoholism Clin Exp Res 1994;18：1040-56）。先前，我们表明，仅仅改变可用的底物就改变了心脏中ATP水解的DG（Kashiwaya Y等人，Am J Cardiol 1997;80：50 A-64 A）。由于任何类型的损伤都会诱导细胞离子分布的定型变化，其中细胞获得Na+，失去K+并肿胀，因此这些损伤的定型变化可能通过简单地改变给予损伤或烧伤受害者的液体组成而逆转。由于这些研究和我们向医学院召集的专家组提出的建议，已经提出了一项建议，即开始研究制造新的复苏液体的可行性（见：液体复苏，治疗战斗伤亡和平民受伤的科学现状，国家学院出版社，1999年）。目标是改善出血和烧伤的标准治疗，这在过去50年中没有改变。我们正在与海军血液研究实验室合作进行这项工作。我们的手稿有关的Δ G的ATP水解的能量梯度的所有9个常见的无机离子之间的额外和细胞内阶段的心脏，肝脏和红细胞现已被接受出版。这些组织的电位从-86到-28到-6 mV不等。我们发现，Na+梯度的能量约为ATP水解能量的1/3，并且由KCl微电极测量的静息膜电位是电泳最渗透离子所需的功函数。因此，离子梯度系统似乎是一个吉布斯唐南近平衡系统依赖于ATP水解的能量。 这导致制备和测试一种新的胃肠外液体系列，用于军事和民用环境中的出血、复苏、头部创伤、中风和烧伤治疗。在军事环境中，一半的致命伤是头部创伤的结果。因此，我们设计了用于治疗与出血相关的头部创伤的新液体。与海军研究办公室合作，这些新液体目前正在全国四个不同实验室的动物模型中进行评估，以确定这些新液体是否降低发病率和死亡率。此外，我们与海军血液研究实验室和约翰霍普金斯重症监护医学部合作，开发了用于治疗大脑中动脉闭塞两小时的新液体。这些新的治疗方法将在未来一年内与现有的治疗方法进行比较，以确定新的液体是否减少大脑中动脉闭塞引起的短暂缺血后的细胞死亡和凋亡。 最后，我们与牛津大学的BHF NMR实验室合作，通过测定镰状细胞贫血患者红细胞中的游离[Mg 2 +]，继续并扩展了我们在游离[Mg 2 +]测定方面的工作。镁的管理已被提议作为镰状危象的治疗。我们在这篇论文中表明，以前的报告游离[Mg 2 +]水平升高是不正确的，由于ATP的损失，导致Mg 2+结合减少。这些观察结果应该是有价值的，在确定适当的治疗镰状危象。这份手稿现已被接受出版。

The energy of the gradients of the nine major inorganic ions in working perfused heart are in near equilibrium with each other, the electrical potential between extra- and intracellular phase and the DG of ATP hydrolysis (Masuda T et al, J Biol Chem 1990;265:20321-34). The metabolism of ethanol increases the resting electrical potential of hepatocytes from 28 to 40 mV (Veech RL et al, Alcoholism Clin Exp Res 1994;18:1040-56). Previously, we showed that merely changing the substrate available altered the DG of ATP hydrolysis in heart (Kashiwaya Y et al, Am J Cardiol 1997;80:50A- 64A). Since injuries of any sort induce a stereotypic change in cellular ionic distributions wherein the cell gains Na+, loses K+ and swells, these stereotypic changes of injury can possibly be reversed by simple changes in the compositions of fluids administered to victims of injury or burns. As a result of these studies and our suggestions to a panel convened by the Academy of Medicine, a recommendation has been made that investigation of the feasibility of making new resuscitation fluids be initiated (see: Fluid Resuscitation, state of the science for treating combat casualties and civilian injuries, National Academy Press, 1999). The goal is to improve the standard treatment of hemorrhage and burns, which has not changed over the past 50 years. We are collaborating in this effort with the Naval Blood Research Lab. Our manuscript relating the Delta G of ATP hydrolysis to the energy of the gradients of all 9 common inorganic ions between extra and intracellular phases of heart, liver and red blood cell has now been accepted for publication. These tissues differ in electrical potential from -86 to -28 to -6 mV. We found that the energy of the Na+ gradient was about 1/3 of the energy of ATP hydrolysis and that the resting membrane potential as measured by KCl microelectrodes was a work function required to electrophoresis the most permeant ion. The system of ion gradients therefore appears to be a Gibbs Donnan near-equilibrium system dependent upon the energy of ATP hydrolysis. This has led to the preparation and testing of a new family of parenteral fluids for use in hemorrhage, resuscitation, head trauma, stroke and the treatment of burns in both military and civilian settings. In military settings, half of all fatal wounds are the result of head trauma. Accordingly, we have designed new fluids for the treatment of head trauma associated with hemmorhage. In collaboration with the Office of Naval Research, these new fluids are currently being evaluated in animal models in four different laboratories across the country to determine if these new fluid decrease morbidity and mortality. In addition, in collaboration with the Naval Blood Research Laboratory and the Dept of Critical Care Medicine at Johns Hopkins, we have developed new fluids for the treatment of two hour occlusion of the middle cerebral artery. These new treatments will be compared with existing treatments over the course of the coming year to determine if the new fluids decrease the cell death and apoptosis following transient ischemia induced by occlusion of the middle cerebral artery. Finally, we have continued and extended our work on the determination of free [Mg2+], in collaboration with the BHF NMR laboratory in Oxford by determining the free [Mg2+] in red cells from patients with sickle cell anemia. Administration of Mg had been proposed as a therapy for sickle crisis. We showed in this paper, that previous reports of the levels of free [Mg2+] being elevated were incorrect due to loss of ATP with result decrease in Mg2+ binding. These observations should be of value in determining appropriate therapy in sickle crisis. This manuscript has now been accepted for publication.