Vacuum Freeze Drying of Frozen Sections for Dry-Mounting, High-Resolution Autoradiography

Specimens no larger than 1.5 × 1.5 × 2 mm were frozen in liquid nitrogen and sectioned, while still frozen, with a refrigerated microtome. The frozen sections were dried in a vacuum, then pressed onto either Kodak NTB10 plates or onto slides which had been coated with Kodak NTB3 emulsion and dried. Radioactive mouse liver was used to test tissue preservation. Intestinal mucosa with Ha-labeled nuclei was used to test the quality of autoradiography. Good cytological detail was preserved in both tissues, with the autoradiographs interpretable at the cellular level.