Fumio Goto

Ultrastructure of the main excretory duct epithelium of the female mouse submandibular gland with special reference to sexual dimorphism.

The fine structure of the main excretory duct epithelium (MEDE) of female mouse submandibular gland was investigated by scanning and transmission electron microscopy and the results compared with the previously established structure of male mouse MEDE. A comparative analysis of the subepithelial capillaries of both sexes was also performed. In this pseudostratified epithelium, principal cell-types were observed: types-I,-II,-III and basal cells. This differed significantly from male MEDE, where type-II and-III are absent and type-I cells are the most numerous. The latter cell-type had abundant mitochondria, a few lipid-containing granules, lysosomes in the infra-nuclear cytoplasm and well-developed basal infoldings. These cells were also characterized by abundant glycogen granules throughout the cytoplasm, many profiles of strands of smooth endoplasmic reticulum in the apical region, and lysosomes in the infra-nuclear region. Type-II cells were the second most numerous. Their most characteristic features were the presence of tubular vesicles which appeared to be invaginated from the plasma membrane, RER, SER, free ribosomes, a few peroxisomes with nucleoids, and primary lysosomes in extremely light cytoplasm. They had many mitochondria throughout the cytoplasm, except in the apical region, a few lipid-containing granules and no basal infoldings. Type-III cells were very few and were characterized by well developed basal infoldings, abundant free ribosomes, RER, SER, vesicles containing moderately dense material, and many lipid-containing granules. They also had many mitochondria throughout the cytoplasm, except apically. Basal cells had a large nucleus and the cytoplasm had few organelles. In the male continuous capillaries predominated in the subepithelial network, and capillary density per 200 μm of epithelium (3.76±1.54) was lower than in the female, as was the number of fenestrae per 10 μm of available endothelium (4.46±1.71). In the female, fenestrated capillaries predominated, and the capillary density per 200 μm of epithelium was 6.76 (±1.54), and the number of fenestrae per 10 μm of available endothelium was 4.91 (±1.77).

A case of epulis osteoplastica.

The tumor mass developed in the 45 lingual gingival region of a 56-year-old female, which was clinically and histopathologically diagnosed as an epulis osteoplastica, was examined with the transmission electron microscope. 1. In histopathological findings. The tumor was covered with laminated flat epithelium, which was severely filled with the connective tissue. Bone tissues were observed between these fibers. 2. In transmission electron microscopic findings. 1) The tissue was recognized to fully contain mature collagen fibers. Partially Osteoblast, Osteoclast and bone matrix can be seen in them. 2) These bone matrix formations suggested the calcification of a typical needle crystal which ran along the crosstriation structure of collagen fibers.