[Histogenesis of adenomas of the parathyroid gland]. / K voprosu o gistogeneze adenom parashchitovidnoi zhelezy.

The similarity of adenomas of the parathyroid gland with other tumours of the APUD-system elements was investigated. The structure of 10 adenomas was studied. The ultrastructural characteristics were compared with the histological structure of the tumour. Various histological variants of the neoplasias were shown to have similar ultrastructure. The tumour tissue was represented by clear transitional and dark cells. In their cytoplasm, osmiophilic granules of the secrete, villae, laminar structures resembling Nissl bodies, fine granular and fine fibrous substances, and lipid inclusions were found. The structural similarity of adenomas with other endocrine-active tumours developing from cells of the neuroectodermal origin (carcinoids, paragangliomas, etc.) was noted. It is suggested that parathyroid glands belong to the APUD-system.

[Ultrastructure of B-cell tumors of the pancreas (insulinomas - insular carcinoid tumors)]. / Ul'trastuktura B-kletochnykh opukholei podzheludochnoi zhelezy (insulinom - insuliarnykh kartsinoidov).

The subcellular organization of 6 B-cell tumours of the human pancreas was studied. The tumour parenchyma consisted of processed light, dark, and moderately electron dense cells containing insulin granules. The presence of villi in the cytoplasm of tumour cells and intranuclear fibrills was demonstrated. The participation of tumour cells in formation of amyloid-like thin-fiber substance filling the intercellular and perivascular spaces was established. The similarity between endothelial cells of tumour vessels and parenchymatous cells was shown. A hypothesis on neuroectodermal origin of the endocrine tissue of the pancreas is supported.