Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf
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Proton microprobe analysis of normal and osteoporosis-affected compact bone. 1. Calcium and other divalent metalsHarangus, L.; Iordan, A.; Preoteasa, E. A.; Grambole, D.; Herrmann, F.; Gomez, S.; Mihul, A.; Lonescu-Tirgoviste, C.; Gutu, D.
Normal and disease-affected bones have been studied by wide- and microbeam PIXE and other IBA methods, but the biologically-active outer surface layer of bone was not examined in detail. In osteoporosis, the altered metabolism of Ca and trace elements leading to low bone density is not fully understood. μPIXE, μPIGE and μPBS were applied to analyze Ca and other divalent cation-forming metals in the outer layer of femur and tibia from normal and experimental diabetes-affected rats, tibia from humans with osteoporosis-complicated diabetes, clinically sound human femoral neck and normal bovine metacarp. Measurements were carried out at the Rossendorf nuclear microprobe with a 3.1 MeV proton beam focused to a spot of ~3 μm, using concomitantly three detectors. Thick (~1 mm) transversal bone sections were scanned near the surface at ~4 μm effective resolution. Hydroxylapatite was used as a reference. Concentrations were determined from PIXE spectra by GUPIX calculations.
Most elements of the second main group were detected: Mg (at minor levels) by μPIGE and μPBS, and Ca (major) as well as Sr and Ba (traces) by μPIXE.
Other divalent ion-forming trace metals found by μPIXE included Cr, Mn, Fe, Ni, Cu and Zn from the transition groups, and Pb. Only normal bones contained Cr, Mn and Cu. Levels of Ca, Fe, Ni and Zn varied strongly even in the same bone, while Sr showed little change. Ca maps evidenced spatially well-defined patterns of bands, and diabetic rat bones presented Ca-poor regions at the surface. The spatial resolution was weaker in the Fe, Zn and Sr maps and improved in mean profiles normal to the surface.
Near the outer surface of bones the maps, profiles and area concentrations of most divalent metals determined by μPIXE evidenced complex features of element distributions and composition, which may be potentially relevant to the osteoporosis.
17th International Conference on Ion Beam Analysis, 26.06.-01.07.2005, Seville, Spain