31P Nuclear Magnetic Resonance Study of Variations in lntra-Erythrocytic ATP Concentration and pH Induced by Surgical Trauma

erythrocytes were studied in patients undergoing a mild surgical intervention. lntra-erythrocytic pH was decreased at the end of the operation; ATP concentrations concomitantly increased, but not highly significantly. These variables re-turned to their initial values by 20 h after the end of surgery. Many intracellular disorders occur in stressed patients. For example, decreases in intracellular ATP in severely ill patients (1, 2) have been demonstrated by classical tech-niques requiring cell lysis. 31P nuclear magnetic resonance (NMR), a noninvasive technique, allows for direct determi-nation of several intracellular variables in living cells (3), including intracellular pH (pH1) and ATP concentration (3-5). In a previous paper (6), we had applied this technique to erythrocytes from uremic patients. Eiythrocytes are rela-tively simple cells, and better knowledge of their intracellu