Peroxisomes are ubiquitous organelies containing enzyme sequences for ,B oxidation of fatty acids, synthesis of bile acids, and ether phospholipids. In the inherited peroxisomal diseases one or more enzymes are deficient in hepatic, renal, and fibroblast peroxisomes. We have examined peroxisomes by light and electron microscopy in 29 duodenal biopsy specimens (21 with normal mucosa) after staining for catalase activity, a marker enzyme.

The literature on the glycocalyx of small intestinal epithelium is reviewed. The structure, general and barrier functions, synthesis, and degradation of the glycocalyx, and pathobiological aspects of the glycocalyx in relation to its barrier function are mentioned. Topics for future research are indicated.

No abstract

SUMMARY The literature of the intestinal M-cell, which is part of the epithelium covering the gut-associated lymphoid tissue (GALT), is reviewed. Attention is paid to the localization, structure, origin and function of this cell, under both normal and pathological conditions.