METHANOL POISONING

本项目的目的是揭示 人类甲醇中毒 据我们所知，只有人类和 猴子表现出特征性的甲醇毒性， 动物，老鼠和老鼠，没有。 本实验室以前的工作 猴子体内甲酸盐的氧化速度较慢 而肝脏四氢叶酸水平 对甲酸盐氧化重要的是， 对大鼠 目前的建议是，首先，检查稳态 肝脏叶酸衍生物和中间体的水平 叶酸生化途径 人体组织将由 首先是器官移植捐赠者， 上消化道手术 程序将包括快速 冷冻肝脏，然后进行HPLC分离， 通过微生物生物测定进行定量。 低浓度的 人肝四氢叶酸和可能低的总肝 叶酸是预期的。 这将支持以下假设， 甲酸盐氧化部分取决于肝脏中的 四氢叶酸。 这些实验将与 对小鼠肝脏叶酸水平的影响 小鼠代谢甲酸盐的速率 三倍于在大鼠中观察到的比率。 我们假设肝脏 小鼠肝脏中的四氢叶酸水平可能高得多。 第二个系列的项目将研究酶的调节 叶酸催化甲酸氧化为CO2 系统;特别是由甲酰四氢叶酸导致的调解 合成酶和甲酰四氢叶酸脱氢酶。 人类 将对肝酶进行定量和定性研究， 胞质组分和均质状态。 动力学 实验和免疫定量实验将是 使用大鼠、小鼠和人肝脏制备物进行。 后来， 将进行分子生物学研究， 这些蛋白质合成的可能遗传调控。 还建议进行研究，以评估 四氢叶酸水平。 亚甲基的酶学研究 四氢叶酸还原酶、甲硫氨酸合成酶和丝氨酸 羟甲基转移酶被描述用于人肝脏。 这些研究应该提供对监管的见解， 甲酸盐和叶酸盐的代谢，尤其是在 人类

The objective of this project is to reveal the mechanism of methanol poisoning in humans. To our knowledge only humans and monkeys display characteristic methanol toxicity whereas lower animals, mice and rats, do not. Previous work in this laboratory has shown that the rate of formate oxidation is slower in monkeys than in rats and that hepatic tetrahydrofolate levels which are important for formate oxidation are much lower in monkeys than in rats. The current proposal is designed, first, to examine steady-state levels of hepatic folate derivatives and intermediates of the folate biochemical pathway. Human tissues will be provided by organ transplant donors first and later by patients undergoing upper gastrointestinal surgery. Procedures will include rapid freezing of livers followed by HPLC separations and quantification by microbiological bioassay. Low concentrations of human hepatic tetrahydrofolate and possibly low total hepatic folate is expected. This would lend support to the hypothesis that formate oxidation depends, in part, on hepatic levels of tetrahydrofolate. These experiments will be compared to studies on folate levels in mouse liver. Mice metabolize formate at rates three times the rates observed in rats. We postulate that hepatic tetrahydrofolate levels may be much higher in mouse liver. A second series of projects will examine the enzymatic regulation of formate oxidation to CO2 as catalyzed through the folate system; specifically the mediation led by formyltetrahydrofolate synthetase and formyltetrahydrofolate dehydrogenase. Human liver enzymes will be studied quantitatively and qualitatively in cytosolic fractions and in the homogeneous state. Kinetic experiments and immunoquantitative experiments will be performed using rat, mouse and human liver preparations. Later, molecular biological studies will be performed to examine the possible genetic regulation of synthesis of these proteins. Studies are also proposed to evaluate the regulation of tetrahydrofolate levels in liver. Enzymatic studies on methylene tetrahydrofolate reductase, methionine synthetase and serine hydroxymethyltransferase are described for human liver. These studies should provide insights into the regulation of formate and folate metabolism in animal species, especially in humans.