Experimental immune diabetes in the rabbit. Light, fluorescence, and electron microscopic studies

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The histopathology of immune diabetes in the rabbit

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Erythrocyte transfer RNA: change during chick development

Radioactive aminoacyl transfer RNA's isolated from erythrocytes in the blood of 4-day-old chick embryos and from reticulocytes of adult chickens were analyzed by chromatography on methylated albumin kieselguhr and freon columns. Embryonic and adult methionyl transfer RNA's showed qualitative and quantitative differences in both chromatographic systems. The patterns for arginyl, seryl, and tyrosyl transfer RNA's in the two cell types were similar, while the leucyl transfer RNA patterns suggested a difference.

Membranous glomerulonephritis: rapidly fatal course

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Clinical and electron microscopic studies of a case of glycolipid lipoidosis (Fabry's disease)

A case of glycolipid lipoidosis (Fabry's disease) in a 27-year-old man is recorded. The case is unusual in that despite extensive disease evidenced by widespread skin lesions, ocular abnormalities, and proteinuria, renal function was only minimally impaired. Electron microscope studies of kidney and skin showed that most cells contained the characteristic lipid described in this condition.

Diabetes mellitus in rabbits immunized with insulin

Normal rabbits immunized with bovine insulin in adjuvant produce circulating autoantibodies that bind large amounts of endogenous insulin (measured by an immunoassay which distinguishes endogenous and exogenous insulin). In a series of nine immunized animals, two not only produced autoantibody but also, as a result of the autoimmune phenomenon, became acutely diabetic. Their blood sugar, circulating antibody, endogenous insulin bound to antibody and morphologic lesions in the islets of Langerhans observed by light and electron microscopy were compared to those of immunized but nondiabetic rabbits for a period of sixty-five weeks.

Diabetes was characterized by weight loss, lipemia and blood sugar levels maintained at 350 to 600 mg. per 100 ml. throughout an experimental period of twenty-one weeks after immunization with insulin. Although circulating antibody levels were unusually high in the diabetic animals, little antibody-bound insulin was evidenced in contrast to the nondiabetic immunized rabbits whose bound endogenous insulin ranged fiom 390 to 2,340 μU. per ml.

Histologic examination by light and electron microscopy at twenty-one weeks revealed absence of beta cell granules and severe damage to the beta cells. Lymphocytic infiltration of the islets was noted in the less severe diabetic in which some beta cells remained, but neither lymphocytes nor beta cells could be detected in the most severely diabetic animal. Alpha cells in each rabbit were normal. Significantly, the nondiabetic immunized rabbits also showed specific changes in their beta cells detectable by electron microscopy.

The surviving, less severely diabetic rabbit remained diabetic and had detectable antibody until sacrificed fourteen months after immunization. Improvement of the animal at this time was indicated by a blood sugar level of 174 mg. per 100 ml., an increase in antibody-bound endogenous insulin, extractable pancreatic insulin in an amount two thirds of normal, and demonstrable granules in most of the beta cells.

It was concluded thai an autoimmune diabetes that closely resembles the early juvenile form can be created in rabbits by immunization with insulin. The possibility that autoimmunity can not only contribute to the diabetic state in insulin-treated subjects but may prove important as an underlying cause in some forms of diabetes is discussed.

Forearm skin capillaries of diabetic, potential diabetic and nondiabetic subjects. Changes seen by light microscope

Light microscopic examinations were carried out on sections of skin from thirty diabetic and 101 control subjects. Examination of the periodic acid-Schiff stained material in a blind study revealed an abnormality in sixteen of the thirty diabetics and seven of the 101 controls. The abnormality is a hyalinization of the normally fibrillar area external to the endothelial cell of the dermal capillaries. Among the diabetics, the abnormality was seen more frequently in juvenile diabetes, long-standing diabetes, diabetes with retinopathy, neuropathy, or nephropathy, and in obese diabetics. The incidence in control subjects was not strikingly higher in those with a family history of diabetes (three in thirty-nine) or in acromegaly (one in eleven) than in other control subjects (three in fifty-one). Electron microscopic observations suggest that the lesion may be due to deposition of material in the collagen containing cuff of the capillary wall rather than to basement membrane thickening.

Lipoprotein patterns in acrylamide gel electrophoresis

Lipoproteins of serum stained before electrophoresis gave distinct patterns in acrylamide gel of 3-percent concentration. Samples compared in parallel on gel slabs showed qualitative differences in migration rates of beta-lipoprotein bands.