Comparison of quantitative x-ray imaging and raster probing in heart cells exposed to sodium-free media
It is shown that with mapping it is possible to sample organelles (here, mitochondrial) more thoroughly than is realistically possible in static raster probes. It is possible to obtain content measurements from a single pixel, several pixels, or the entire mitochondrion. When the elemental contents of the regions are compared with the contents of mapped whole mitochondria, no differences are found. The whole mitochondria value was obtained by outlining the entire mitochondrion. The sodium response to reversal of the sodium gradient follows the same trend as in the quantitative values reported previously for cultured heart cells and rabbit papillary muscles.