SENSITIVITY IN ELECTRON MICROSCOPE AUTORADIOGRAPHY II. EFFECT OF HEAVY METAL STAINING

Abstract

In quantitative electron microscopic autoradiography test specimens for sensitivity usually consist of plastic or protein films 500-1000 Å in thickness. For tritium, the applicability of sensitivity values derived from such specimens to biologic sections which had been stained with heavy metals was determined. It was found that, within the range of section thickness used for electron microscopic autoradiography, fixation with OsO₄ followed by uranyl acetate staining increases self-absorption by less than 7% over that seen in Epon sections of the same thickness. A somewhat larger effect is seen in sections used for light microscopic autoradiography. The effect on electron microscopic autoradiographic resolution is estimated to be within 10%.