Research in radiobiology. Annual report of work in progress in the internal irradiation program

Abstract

The purpose of this study was to characterize the surface density, morphology and ultrastructure of bone-s urface "cells at risk" to radionuclides in a site of low radiation-induced osteosarcoma incidence. Particular attention was paid to the bone-lining cells which cover the majority of the .trabecular surface. The numbers of osteoblasts, osteoclasts, and bone-lining cells were quantified on trabecular bone surfaces of lum-thick plastic sections of distal radii from control beagles of different ages.. The average com osite surface density of bone-lining cells was found to be about 450 cells/mmt. Most of the lining cells had very flat, apparently disk-shaped, nuclei of about 10-15 Wn in diameter and often less than lum in thickness. Cells with more oval or round nuclei were also encountered. The bone-lining cell nuclei were often found in areas containing capillaries bordered by fat cells. The cytoplasm of the lining-cells was often less .than •0.lum in thi ckness as it ..2, ..