sterisk* \<0.00 compared with the initial value. *Double asterisk* \<0.00 compared with the initial value. *Triple asterisk* \<0.000 compared with the initial valueFig. 0Intraoperative plasma concentrations of **a** asparagine, **b** glycine, **c** alanine, **d** serine. Patients received 0.0 L cardioplegic solution at the onset of cardiopulmonary bypass, which contained 000 mM histidine for induction of cardioplegia. Values are shown as mean ± SD. *Triple asterisk* \<0.000 compared with the initial value