Quantitative studies of the renal corpuscles IV. Determination of normal values in various age categories, and an analysis of the possible influence of physiological degrees of arteriolosclerosis.

A quantitative study including total and differential counts of nuclei and determination of mesangial and total glomerular area was carried out on kidney tissue from 21 persons without renal disease, in order to determine the normal values of glomerular parameters and to estimate the possible influence of age and physiological degrees of arteriolosclerosis. No age dependency was found to exist for the glomerular parameters within the age category of 17 to 45 years. Above the age of forty-five a rise in mesangial area per cent of total area and mesangial nuclei per cent of total nuclei was found on increasing age, while a decline on increasing age was demonstrated for epithelial nuclei per cent of total nuclei. The mean value of mesangial nuclei per 1000 micron2 of mesangial area was found to be significantly higher in the older age category than in the younger. Arteriolosclerosis did not appear to influence the parameters. The study also attempted to describe the three variance components: interrenal, interfocal and interglomerular variation. Interfocal variation was the smallest part of the total variation, and interrenal plus interfocal variation was at most of the same size os interglomerular variation.