Myelin figures in the basal-granulated cells of human Brunner's glands.

Peculiar myelin figures were abundantly found in some basal-granulated cells including S, D1 and I cells in human Brunner's glands. Intense acid phosphatase activity was found in the periphery of the myelin figures, indicating that they were secondary lysosomes or residual bodies. The acid phosphatase activity was also found in some secretory granules. There were some secretory granules which were partly membranous in content, suggesting the initial stage of their degradation into myelin figures. There were also features indicating the fusion of secretory granules with the myelin figures. All these findings suggest that the myelin figures are the products of lysosomal degradation of secretory granules. The rate of occurrence of basal-granulated cells containing myelin figures in Brunner's glands tended to be higher in subjects with duodenal ulcer than in cases of gastric cancer or ulcer.