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BIBTEX RIS

Contribution of energy‐filtering TEM to the detection of calcium: Application to mast cells

1994; Wiley; Volume: 173; Issue: 3 Linguagem: Inglês

10.1111/j.1365-2818.1994.tb03443.x

1365-2818

Marianne Horoyan, M. Soler, José Miguel García‐Martín, A M Benoliel, M. Fraterno, Marc Passerel, E. Katchburian, Pierre Bongrand, C. Foa,

Biotin and Related Studies

Summary The ultrastructural distribution and quantification of calcium in mast cells prepared by anhydrous processing was investigated by energy‐filtering transmission electron microscopy (EFTEM) using a Zeiss 902 electron microscope. Optimal conditions for calcium detection were determined using inorganic (calcium phosphate) and organic (calcium‐loaded chelex beads) standards with known amounts of calcium. Electron energy‐loss spectroscopy (EELS) revealed calcium at the L 2,3 edge and also at the M 2,3 edge for all specimens examined. Comparison with X‐ray microanalysis confirmed the results obtained with EELS. Electron spectroscopic imaging (ESI) was applied for mapping calcium both in standards and in cells and we showed that mast cell granules were the main site of calcium localization. Although, results have shown that a combination of analytical techniques is required to obtain reliable results.