[Ultrastructure and elemental composition of pancreatic stones].

Four patients with pancreatic duct stones (PDS) and one with calcium deposits (CD) were diagnosed and surgically cured. The ultrastructure and elemental composition of PDS were studied by scanning electron microscopy and energy dispersive X-ray fluorescence. The results indicated that the outer shell of PDS, with dense texture, contained 96.29% of calcium (Ca), while the amorphous reticular inner nidus mainly contained sulphur (S) and chlorine (Cl). CD and PDS were manifestations in the process of pancreatic stones (PS) formation at different stages. As regards the formation of PS, the depressed gene expression played a key role in the reduction of PSP (Pancreatic Stone Protein), which made pancreatic acini reduce PSP biosynthesis rates. The consequence arising therefrom was that the supersaturated calcium carbonate (CaCO3) in pancreatic juice became inadequately inhibited. Thus the calcium carbonate became crystallized and deposited onto the reticular inner protein nidus (RIPN), which developed from the compilation of micro-protein-plugs that had grown from pathologically hyperconcentrated total proteins (mainly containing lactoferrin) in pancreatic juice. The RIPN gave a basis on which the calcium carbonate precipitated and formed PS.