title: The influence on enzyme activity of storage of tissue blocks at -70 degrees C.
abstract: Blocks of tissue from various organs of the rat have been chilled by precipitate immersion in n-hexane cooled to -70 degrees C, and then stored at -70 degrees C. At various intervals (up to 14 days) after chilling, cryostat sections were prepared from these blocks and assayed for the activity of a variety of enzymes. Enzyme activity was measured by scanning and integration microdensitometry. With the exception of acid phosphatase and cytochrome oxidase, all enzymes assayed were stable for at least 7 days after storage at -70 degrees C and most were stable for 14 days, Storage of fresh-frozen sections at -30 degrees C in the cabinet of the cryostat, for up to 24 h, had little effect on enzyme activity.
mesh_terms: D000818:Animals; D004798:Enzymes / Q000378:metabolism*; D005260:Female; D005615:Freezing; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D013048:Specimen Handling; D014021:Tissue Preservation
chemical_list: D004798:Enzymes