Do the cardiac glands exist? 5. The dog.

The authors performed histological and histochemical investigations on the so-called cardiac glands and gastric glands of the dog, and compared the data on these glands. The conclusions were as follows: 1. The so-called cardiac glands have a number of parietal cells and cells distributed in the same glandular base contain fine pepsinogen granules. However, these glandular cells are filled with a PAS-positive substance. Accordingly, the so-called cardiac glands are nothing but undifferentiated gastric glands. 2. Due to the deep gastric pits, the outer layer of the mucous membrane in the clear zone is loose, and a distribution of a smaller number of blood vessels can be expected. These facts may demonstrate a pale or clear appearance of the mucous membrane in the same zone. 3. The gastric pits in the dark zone are extremely shallow. Accordingly, the mucous membrane in this area is dense and a distribution of a large number of blood vessels can be expected. This probably produces a dark color, i.e., reddish brown. 4. The chief cells in the glandular base of the clear zone contain a number of fine and coarse PAS-positive granules. These granules also are a violet color with PAS-AB (pH 2.5) stain. This color resulted from sialomucin. The above mentioned facts mean that the clear zone is an undifferentiated region of the gastric glands. 5. The chief cells distributed in the glandular body and base of the dark zone are PAS-negative and contain no sialomucin. Accordingly, the same zone is the differentiated region of the gastric glands.(ABSTRACT TRUNCATED AT 250 WORDS)