Abstract
Chronic nephritis with edema (nephrosis) is associated with a marked albuminuria and a lowered total serum protein as pointed out by Epstein. 1 The importance of the level of the albumin fraction in relation to the appearance of the edema, both clinically and experimentally, has been emphasized by Barker and Kirk. 2 In an attempt to study the effect of the low proteinemia on the kidneys, a similarly low serum albumin level (about 1 gm. per 100 cc. of blood serum) has been produced and maintained in a series of dogs by plasmapheresis. Renal tissue has been obtained from these dogs by nephrectomy or by destroying the animal at periods varying from 2 weeks to 6 months. Gross and microscopic studies have shown the beginning and rather rapid progression of a degenerative renal lesion.
The first changes were noticeable at the end of 2 weeks at which time the kidney appeared swollen. The cortex was relatively thickened and was a brownish-gray color. Microscopically, cloudy swelling was noted particularly in the convoluted tubules together with desquamation of the tubular epithelium and extrusion of many nuclei. There was some hyaline droplet formation and occasional shrinkage of the glomerular tufts. After about one month of plasmapheresis, the gross appearance of the kidneys was quite normal but microscopically, in addition to the cloudy swelling and breaking down of the tubular epithelium, there was fatty infiltration along the basement membrane of the tubules and there were small areas of round cell infiltration in the convoluted portions. An occasional glomerulus showed atrophy together with hyalinization and thickening of the capsule.
Tissue obtained at 2 months showed a still more marked atrophy of the tubules. Large areas of round cell infiltration and a definite connective tissue replacement was seen all through the inner half of the cortical tubular region.
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