Slicing

The embedded core was oriented in the Krumdieck tissue slicer with the endocardial surface toward the blade, such that the cutting plane was parallel to the myocyte long axis; a supplied weight maintained downward pressure. Slice thickness was set at 250 μm. The instrument passed the core repeatedly and automatically across a replaceable stainless steel blade while immersed in 4°C, sterile buffer. Circulating buffer floated the resultant slices into a glass trap and a collecting tray.

Modified calcium-free Tyrode's for heart slicing: NaCl 111 mmol/l; KCl 16 mmol/l; HEPES 10 mmol/l; NaHCO₃ 4.2 mmol/l; MgSO₄-7H₂O 0.4 mmol/l; glucose 5.6 mmol/l; 2,3-butanedione monoxime (BDM) (B0753, Sigma-Aldrich, St. Louis, Missouri) 20 mmol/l; (pH 7.2) at 4°C in air. Components are added to sterile water and filter-sterilized.