A Further Study of the Response of the Opossum Kidney,Didelphys virginiana to injury

Abstract

In previous communications( 1 , 2 ) consideration has been given to changes in the oppossum kidney of an atypical order, resulting from an injury of an unknown nature, which resulted in the establishment of a cytological reaction on the part of these organs which would fall in the category of a chronic type of nephropathy very largely confined to the glomeruli. To the total number of 58 opossums previously studied, there must now be added observations on 5 additional animals. The present investigation is based not only on the study of the kidneys of the 5 new animals but on a critical review of the histological material representing the group as a whole; 63 adult animals of unknown age. In both of the above referred to studies as well as in this further study, the observation of dominant interest has been in the reaction of the glomeruli of 19 of these animals to an injurious agent: In the kidneys of such animals there occurs a variable number of glomeruli larger in diameter than unaffected structures in which the capsule is lined by a parietal layer of Bowman's membrane consisting of high, usually discrete, columnar epithelial cells. These cells decrease in height and the degree of cellular differentiation as the base of the glomeruli is reached. At this point there is a sharp transition of this order of columnar cell to the flattened, squamous type of cell normal for the glomerular membrane which is reflected as the visceral layer of epithelium over the capillary tufts. Such capillary networks are usually definitely abnormal in structure with thickened walls which frequently have the appearance of syncytial layers of endothelial tissue. Fig. 1 and 2.

In the previous studies( 1 , 2 ) no explanation was offered for the development of these atypical glomeruli.