Figure 77-17 Day-to-day and cumulative nitrogen balance in patients receiving 1-alanyl-1-glutamine dipeptide-supplemented (filled columns) or conventional-amino-acid total parenteral nutrition (TPN) (open columns). These results illustrate a beneficial effect for increasing glutamine concentration in maintaining nitrogen balance. ***P <.001; **P < .01. (Adapted from Stehle P, Zander J, Mertes N, et al: Effect of parenteral glutamine peptide supplements on muscle glutamine loss and nitrogen balance after major surgery. Lancet 1:231, 1989.)