ヒト気管腺の電子顕微鏡的観察

とくにoncocyteおよびoncocyte様細胞について

抄録

Twenty-nine cases of human tracheal glands were studied in electron microscopy. The materials used in this study were taken from patients whose ages ranged from 1 to 90 years old of both sexes.
The tracheal glands were composed of occasionally branched tubulo-alveolar glands consisting of the duct and the terminal portion of both mucous and serous type, and furthermore, smoothmuscle type myoepithelial cells surrounding the outside of the terminal portions.
Both oncocytes and oncocytic cells appeared everywhere in the gland, both in the duct and also in the terminal portion epithelium. They were generally seen in a cluster, but sometimes in solitary form within the glandular epithelium.
Oncocytes were tightly packed with an unusually large number of atypical hypertrophied mitochondria. On the other hand, the oncocytic cells contained variable numbers of such atypical large mitochondria in addition to usual cell organelles. These findings in the oncocytic cells are strongly suggestive that the oncocytic cell is a transitional type cell between the normal glandular cell and the typical oncocyte within the gland. Atypical mitochondria in such cells were almost devoid of intramitochondrial granules, and had conspicuously larger sizes than those of usual ones.
These atypical hypertrophied mitochondria were often provided with tightly packed bundles of longitudinally or arcuately arranged cristae, as well as a dilated matrix with either dense globules or crystalloid inclusions. The cells containing such peculiar mitochondria had to some extent similar characteristics to those of the usual glandular cells. However, in this study no myoepithelial cells exhibited any morphological signs of transforming into oncocytes or oncocytic cells.
Increased numbers of oncocytes and oncocytic cells tended to be seen more frequently in aged individuals, and thus this oncocytic degeneration of the gland may be considered as one of the changes due to aging within the glandular tissues of man.
In some cases, a few annulate lamellae connected to the limiting membrane of the rough endoplasmic reticulum were observed, however, their functional significance remains obscure.