Comparison of quantitative x-ray imaging and raster probing in heart cells exposed to sodium-free media

Abstract

Quantitative biological electron probe x-ray microanalysis (EPXMA) ideally makes use of two approaches in examination of samples: static raster probing and quantitative x-ray imaging. Efficient use of expensive microanalytical equipment requires intelligent decisions on the appropriate strategy for optimizing data collection. A low resolution, short dwell time map (for example, 64 × 64 pixels by 2 seconds) may survey one to several cells at low magnification and provide adequate statistics for most structures and elements. Elements, notably Ca, present in low concentrations within small regions may require the acquisition equivalent of long static raster probes, increased numbers of images from low resolution maps, higher resolution maps, longer dwell time maps, or a combination of these options.We examined raster probe and mapping results in cultured heart cells. In these cells EXPMA has been demonstrated to be an appropriate tool to observe the results of perturbation of the Na-Ca gradient, brought about by incubation of cells in low Na or Na-free media.