Protein plugと膵石の比較研究

Abstract

The fine structure of pancreatic stones was investigated with a scanning electron microscope and an X-ray microanalyser. Pancreatic stones were obtained from four patients with alcoholic calcified chronic pancreatitis by surgical procedures. All the stones were radiopque. Inorganic constituents were also investigated by powder X-ray diffractometry. Calcium in the pancreatic stones was found in the form of calcium carbonate crystals of a calcite type in both the cryptocrystalline and crystalline states. Pancreatic stones could be classified into two types, type A and type B, by the fine structure and calcium distribution. Type A stones showed zonation and were considered to be formed by layered depositions of calcite. There was no distinct central core, and calcium was diffusely distributed. Type B stones in contrast, showed a large and distinct central core and an outer shell. It was thought that the central core was formed by synchronous crystallization of calcium-deficient amorphous substances and that the outer layer was formed by layered depositions of calcite around the central core. Layered deposition of calcite progressed most probabaly from inside to outside. Pancreatic stones were thought to be formed by deposition of calcite on protein plugs because of their structural similarities including interlacing network fibrils and filling by an amorphous substance in the network. The central cores of pancreatic stones may be protein plugs.