| Abstract: |
Data from digital electron probe x-ray microanalysis (EPXMA) images can be used to generate high resolution profiles of Ca binding within sarcomeres of vertebrate striated muscle. While ratios of elemental peak to bremstrahlung at each point (Hall method) have been used in many studies to allow comparison of data taken from different samples, this procedure has limitations for our application. A different normalization procedure is described here which provides a means of assessing variation among elemental and bremstrahlung profiles obtained from different images and samples. Freeze dried cryosections of chemically skinned frog or rabbit skeletal muscle were prepared as previously described. Digital EPXMA images were collected for 24 to 36 hours using a Zeiss EM910 STEM and an Oxford ExL2 microanalysis system. Calcium and bremstrahlung counts were summed within one pixel wide masks placed at successive positions along each half sarcomere, as previously described, using an automated routine in IPLAB on a Power Mac 7100. © 1998 Microscopy Society of America. |
