Willy Gepts

Islet Cell Survival Determined by Morphology An Immunocytochemical Study of the Islets of Langerhans in Juvenile Diabetes Mellitus

The cytologic composition of the pancreatic islets of 58 insulin-dependent diabetics with age of onset of the disease before the age of 40 and a duration of from a few days to 37 years was studied with the aid of Sternbergers immunocytochemical method. Four types of islet cells were stained with specific antisera: β cells (insulin), α cells (glucagon), D cells (somatostatin), and PP cells (pancreatic polypeptide). β cells were found in 14 of 16 recent-onset cases, in seven of 14 patients having diabetes for less than 11 years, and in five of 28 patients in whom the disease had been present for a longer time. In all these cases, the number of β cells was well below normal. They showed cytologic features of functional hyperactivity. The majority of the islets, even in recent-onset cases, were devoid of β cells and were composed of thin cords of islet cells. Immunocytochemical staining revealed that, contrary to the classic opinion, these cells are not inactive but are actively secreting glucagon or somatostatin. In many long-term juvenile diabetics, the glucagon-containing α cells appeared very numerous, but it remains to be ascertained whether this represents an apparant or a true hyperplasia. Insulitis was found in 11 of the 16 recent-onset cases. In one case, the lymphocytic infiltration was found only in islets containing β cells but was strikingly absent in the islets composed of glucagon-, somatostatin-, and PP-cells. Images of islet regeneration, with neoformation of β cells and other islet-cell types from centroacinar and ductular cells could still be detected focally in a few recent-onset cases. With a disease of longer duration, an atypical type of islet regeneration, originating in the epithelium of small- and medium-sized ducts, becomes more prevalent and produces islets solely composed of PP cells.

The basic structural lesion of persistent neonatal hypoglycaemia with hyperinsulinism: deficiency of pancreatic D cells or hyperactivity of B cells?

SummaryPancreatic tissue obtained at subtotal pancreatectomy from 15 infants with persistent hypoglycaemia with hyperinsulinism, and autopsy specimens from 23 age-matched normoglycaemic controls, were studied with morphometric methods after immunocytochemical staining of the four main islet cell types (A, B, D and pancreatic polypeptide cells). In three cases, a focal lesion was detected by gross examination. Macroscopic or microscopic examination did not distinguish the 12 other cases from controls. As found previously, nesidioblastosis was not a specific feature of the pancreas in infantile hypoglycaemia, being observed in age-matched controls as well. In cases with hypoglycaemia the volume density of B cells was not significantly increased; that of the A cells was within normal range. The volume density of pancreatic polypeptide cells was markedly augmented and that of somatostatin cells was significantly decreased. The mean nuclear volume of the B cells was increased by 40% in cases with diffuse changes, but in cases with a focal lesion this increase was restricted to the abnormal area. This finding is of decisive importance for diagnosis and has therapeutic implications. The increase in B-cell nuclear size is thought to reflect an enhanced functional activity of these cells. On the other hand, the figures obtained for the volume density of B and D cells must be viewed with some reservation because degranulation may interfere with accurate detection of these cells.

Transplantation of Purified Islet Cells in Diabetic Rats: I. Standardization of Islet Cell Grafts

A standardized procedure was developed for the preparation of rat islet cell grafts with selected cell number and composition. After collagenase digestion of pancreases and elutriation of tissue fragments, islets were isolated and dissociated, and cells were purified by autofluorescence-activated cell sorting. Approximately 30% of the initial β-cell mass was lost during digestion and elimination of small mostly exocrine particles. Fifty percent was recovered in isolated islet preparations and 30% in the purified β-cell suspensions of >95% purity and viability. Sorting according to cellular flavin adenine dinucleotide content discriminated islet β-cells from islet endocrine non–beta-cells, fibroblasts, leukocytes, and exocrine cells. Purified endocrine islet cell grafts were prepared by aggregating 106 pure β-cells with or without 8 × 105 pure endocrine non–²-cells. In contrast to intact islets, the purified aggregates were devoid of nonendocrine and damaged cells. Intraportal implantation of a pure β-cell graft rapidly and permanently normalized the diabetic state of streptozocin-administered animals. The standardized preparation of purified β-cell grafts allows us to address several metabolic and immunological questions concerning islet cell transplantation in diabetes.

Metastasizing neuroendocrine carcinoma of the larynx with calcitonin and somatostatin secretion and CEA production, resembling medullary thyroid carcinoma

A 55-year-old man presented with a metastasizing moderately differentiated neuroendocrine carcinoma of the larynx (atypical carcinoid). Immunocytochemical demonstration of neuroendocrine markers (neuron-specific enolase and chromogranin-A) and presence of membrane-bound neurosecretory granules in the cells established the neuroendocrine nature of the tumour. In addition, the tumour was found to produce calcitonin, somatostatin and carcino-embryonic antigen (CEA). Calcitonin and somatostatin were also secreted. On the basis of this particular marker constellation the tumour closely resembles medullary thyroid carcinoma. Review of the recent literature on carcinoids of the larynx reveals immunoreactivity for calcitonin and CEA in a high percentage of cases.

Ontogeny of hormone-secreting cells of the rat pituitary gland: An immunocytochemical study on dissociated cells

SummaryAn immunocytochemical study was undertaken in foetal, prepubertal and mature rats to determine the time of differentiation of various types of adenohypophyseal cells during development. Freshly dissociated pituitary cells from foetal (18–21 days postconception), neonatal (from birth up to 30 days) and adult rats (more than 8 weeks) were characterized using immunocytochemical methods. All types of hormone-producing cells were present at day 18 postconception, although only 20% of the cells were immunolabelled. Adrenocorticotropin (ACTH)-secreting cells accounted for the highest number of hormone-positive cells. Growth hormone-secreting cells increased remarkably from day 18 postconception onwards. Prolactin-secreting cells were not seen in the foetal adenohypophysis and did not start to increase until 10 days after birth, whereas by that time the number of ACTH, thyrotropin, follicle-stimulating and luteinizing hormone-secreting cells had stopped increasing. By day 30 after birth, 80–95% of the cells were immunoreactive.

Presence of Pancreatic Hormones in Islet Cells With MHC-Class II Antigen Expression

In the normal rat pancreas, only few islet cells express MHC-class II antigens. Their nature and function has not yet been elucidated. We report a method for the purification of la-positive islet cells by fluorescenceactivated cell sorting. The isolated mononuclear cells appear of nonendocrine origin but contain vacuoles with partially digested secretory vesicles. Both insulinand glucagon-immunoreactive granules were identified in these vacuoles of varying size and composition. It is suggested that at least part of the rat islet cells with class II antigen expression can exhibit phagocytotic properties leading to the uptake of fragments from damaged endocrine cells. This functional characteristic may implicate this particular islet cell type in the pathology of the endocrine pancreas in type I diabetes.

Primary (autoimmune?) parathyroiditis

A case of idiopathic hypoparathyroidism associated with Pagets disease in an eightyfive-year-old man is reported. Pathological and biological features suggest the possibility of an autoimmune aetiology. The association of idiopathic hypoparathyroidism and Pagets disease is probably fortuitous.

Unusual Nonimmunoglobulin-Containing Inclusions in a Case of Follicular Large Cell Lymphoma

Intracytoplasmic inclusion bodies were found in a case of follicular large cell lymphoma. They did not react with anti-immunoglobulin antisera and showed no enzyme reactivity. On electron microscopy the inclusions consisted of loosely packed fibrillar material not surrounded by a membrane or by rough endoplasmic reticulum. They were found only in the large lymphomatous cells. Immunocytochemistry showed a reactivity of these cells with anti-HLA-Dr and the OKT10 monoclonal antibodies. The nature of the inclusions remains unknown. They differ significantly from those described in the literature in cases of B-cell lymphoproliferative disorders.