Figure 1

Focused microwave irradiation is the most suitable tissue fixation method.
Hearts were prepared by three different methods: focused microwave irradiation (FMW), rapid freezing method, in which hearts were isolated immediately after thoracotomy and then quick-frozen in liquid N2, and by delayed freezing, whereby hearts were isolated 10 min after cervical dislocation. The time required for inactivation of postmortem enzymatic activity was shortest in FMW (0.96 s), followed by rapid freezing (approx. 20 s after thoracotomy) and delayed freezing (10 min after cervical dislocation). (a–c) Amounts of metabolites in the glycolytic pathway(a), tricarboxylic acid (TCA) cycle (b), values for NADH/NAD+ ratio (c) and amino acids (d) were determined by CE-MS. *P < 0.05, **P < 0.01 (n = 6).