Figure 2

In-air micro-PIXE analysis of an area of dense particles phagocytosed by macrophages in lung tissue from the PAP patient. The microbeam was focused on an area of 54 μm × 61 μm. Two-dimensional analysis was performed on the distribution and intensity of elements in the dense particle area of the lung. The strength of Fe, P, Si, and S in lung tissue is shown by gray to white dots. The Si content is high on the elemental map. The content and distribution of Fe, Si, and P is shown in mixed colors (Mix) as follows: Fe (red), Si (green), and P (blue). A serial section of the area subjected to micro-PIXE showed dense black particles and accumulation of macrophages by Berlin blue staining (BB) (×1000). Sideromacrophages containing rich iron (stained blue) phagocytosed the particles (black).