Computer quantification of intracellular gold particles

We describe the use of image software programs available for both PC and Ma cintosh((R)) computers to quantify the accumulation and distribution of gol d-labeled constructs within two-dimensional cell sections. The compartmenta lization of a biotinylated-peptide was visualized in radiation-induced fibr osarcoma cells by transmission electron microscopy, using a gold particle-s treptavidin conjugate. This study illustrates the ease of tabulating gold p articles observed in scanned electron micrographs, using Adobe((R)) Photosh op((R)) in conjunction with the public domain NIH Image program (Version 1. 61). Quantitative information regarding the localization of molecules insid e cells is crucial in defining their sites of action and in developing more effective therapeutic agents.