Figure 4

In-air micro-PIXE analysis of an alveolar macrophage from the surfactant-rich area of PAP lung. The microbeam was focused on a 30 μm × 35 μm area of the lung to analyze the intracellular distribution of elements in an alveolar macrophage. Two-dimensional analysis was performed on the intracellular distribution and intensity of elements in an alveolar macrophage. The strength of Fe, P, Si, and S in lung tissue is shown by gray to white dots. Cell morphology was identified by the distribution of P located in the surfactant-rich area, which was identified by the distribution of S. The intracellular content and distribution of Fe, S and P in an alveolar macrophage are shown in mixed colors (Mix) as follows: Fe (red), S (green), and P (blue). A serial section of the area subjected to micro-PIXE showed sideromacrophages (arrow) containing iron (blue) (× 1000) by Berlin blue staining (BB) in surfactant (arrowhead).