EXAMINATION OF VARIOUS METHODS FOR THE INTENSIFICATION OF AUTORADIOGRAPHS BY SCINTILLATORS

Despite published claims of increased radioautographic efficiency in the presence of scintillators, the methods tested in this laboratory mainly gave negative results. However, the impregnation of tissue blocks with scintillators during the histological processing procedures yielded positive results. When scintillators were added during dehydration as well as infiltration and Epon embedding, a moderate increase in reaction intensity in light microscope radioautography and a 75% increase in electron microscope radioautography was obtained. From comparative experiments it appears that the most effective step was the addition of 2,5-diphenyloxazole (PPO) and 1,4-bis-2-(4-methyl-) 5-phenyloxazolyl - benzene (POPOP) to the propylene oxide-Epon mixtures used for infiltration of tissue blocks. Fischer et al and Fischer and Werner added 1% PPO to Epon and reported a three-fold increase in reaction intensity with 3H-labeled specimen and a 12-15 fold increase with 14C-labeled specimen. During histological processing the application of scintillators is easily carried out, but it will be necessary to examine whether or not resolution is affected.