Abstract
The fine surface structure of dog gastric mucosa was observed by scanning electron microscopy. Firstly, we examined the normal gastric mucosal surface: These samples were biopsied from the stomachs of three dogs of about three months of age. 1) In the fundic gland area, gastric small pits (foveolae) were systemically formed with round glandular lumen, which was separated in multiple branches and with an uniformly thick surrounding wall. 2) In the pyloric gland area, foveolae consisted of oval-shaped, simple tubular and slightly irregular glandular lumen. And the surrounding wall was thicker than in normal fundic glands. 3) In the intermediate zone, the structure of the foveolae was seen to be composed by a mixture of the modes of the fundic and pyloric glands. Next, the abnormal gastric mucosa produced by ENNG was studied. Gastric carcinoma in the dog is known to be frequently induced by oral administration of pellets immersed in N-Ethyl-N'-nitro-N-nitrosoguanidine (ENNG) solution. 1) elevated lesions: a) Malignant mucosal surface was rough and jagged and the foveolae con-sisted of irregularly deformed glandular lumen. d) In benign mucosal surface, the foveolae were seen as a structureless surface devoid of glandular lumen. 2) Depressed lesions: a) In the case of exposed cancer, the structural arrangement in the gastric surface was lost, while, even in the unexposed cancer, deformed glandular lumen could be noted. b) In early gastric cancer, the gastric small pits (foveolae) of signet-ring cell carcinoma consisted of a jagged, irregular surrounding wall and round glandular lumen. The pits of tubular adenocarcinoma consisted of a thick, irregular wall and of oval-shaped glandular lumen.
