Ultrastructure and secretory cycle of the islands of Langerhans cells in pancreatic cancer]

By electron microscopy, the islets of Langerhans of 5 patients with cancer of the pancreas were studied. The most obvious ultrastructural changes were found in the insulin-producing B-cells. Their cytoplasm contained a reduced number of secretory granules. Many B-cells were seen at different stages of the secretory cycle, part of them being destructed. On studying secretory process, the formation and maturation of B-granules was demonstrated in the cistern of ergastoplasm without the Golgi complex being involved. The data obtained suggest the functional tensity of the insular tissue at the neoplastic process in the exocrine part of the pancreas.     

Autotransplantation of islands of Langerhans in dogs

Six dogs received intraportally an autograft of isolated non purified pancreatic islets after total pancreatectomy. The isolation was made by collagenase technique, using a quarter to a half of the total pancreatic mass. The results of different transplantation technics are discussed. We conclude the necessity of: 1) a good venous distension of the pancreas, 2) the use of at least a third of the pancreatic gland to prepare the islets, 3) a tissue reinjection the closest as possible of the portal vein.     

Formation of human islands of Langerhans cells from the epithelium of the acini and ducts]

The contents of endocrine cells in the epithelium of ducts and the number of acino-insular elements in exocrine parenchyma and in pancreatic islets were estimated by means of the dotted method in semithin sections prepared from the pancreas of the human embryos (4--7 months of embryogenesis) and of adult persons (40--50 years of age). Endocrine cell formation was noted in all stages studied in ontogenesis. Quantitative data demonstrated that the epithelium of the ducts is the main source for insulocyte formation. In the pancreas of both human embryos and adult persons, acino-insular transformation participated in the formation of endocrine elements. The data obtained gave a certain evidence on entodermal origin of the pancreatic islets in the human pancreas.