Pixe microanalysis of trace elements of normoxic, ischemic and reperfused rat hearts.

With a 3 x 3 mu m(2) proton microbeam spatial distributions of Na, Mg, P, S, K, Ca and Fe were measured via PIXE in 50 x 50 mu m(2) areas of rat heart, sliced into 10-15 mu m thick cryosections. The isolated rat hearts were subjected to normal perfusion, ischemia and reperfusion. Substantial changes in the elemental distribution were found in tissue after 40 min. of reperfusion, particularly indicated by locally elevated Ca and decreased K levels. Electron microscopic examination was used for assessment of artefacts due to sample preparation and handling. Results of stained cryosections analyzed via STIM demonstrated that this latter technique can be employed prior to PIXE analysis to localize individual cells in freeze-dried cryosections.