passages.id: split_1_test_636_passage
passages.type: progene_text
passages.text: Among mucus - secreting cells , the gastric gland mucous cells , Brunner 's glands , accessory glands of pancreaticobiliary tract , and pancreatic ducts exhibiting gastric metaplasia are unique in that they express class III mucin identified by paradoxical Con A staining composed of periodate oxidation , sodium borohydride reduction , Con A , and horseradish peroxidase reaction .