title: Endoscopic biopsies of normal duodenal mucosa.
mesh_terms: D001706:Biopsy; D004386:Duodenum / Q000033:anatomy & histology / Q000473:pathology*; D019723:Endoscopes; D005069:Evaluation Studies as Topic; D006652:Histological Techniques; D006801:Humans; D007413:Intestinal Mucosa / Q000648:ultrastructure