Microbeam PIXE analysis of Na, K, Mg, and Ca in severely damaged cardiac tissue

The aim of the study was to measure with microbeam PIXE elements such as Na , K, Mg, and Ca in cardiac tissue after various treatments in vivo, which a ffect the cardiomyocyte integrity. It was assumed that local deviations fro m normal electrolyte levels indicate the degree of cardiac damage. The firs t step in this feasibility study was comparison of severely damaged cardiac tissues with controls. Severe cardiac damage was introduced by the so-call ed Ca paradox. Experiments were performed with isolated rat hearts, perfuse d retrogradely with an oxygenated crystalloid buffer. Results indicated tha t severe cardiac damage was accompanied with almost complete disappearance of the normal intracellular electrolyte composition as a result of the loss of membrane integrity. Identifications of smaller and more locally present ischemic damages on basis of altered electrolyte levels appeared to be fea sible. However, the prerequisite was that the mobility of electrolytes be k ept under control during tissue sampling and sample preparation, when physi ological mechanisms stop to maintain gradients.