Springer Online Journal Archives 1860-2000
Summary Blocks of tissue from various organs of the rat have been chilled by precipitate immersion in n-hexane cooled to −70° C, and then stored at −70° 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 integrating microdensitometry. With the exception of acid phosphatase and cytochrome oxidase, all enzymes assayed were stable for at least 7 days after storage at −70° C and most were stable for 14 days. Storage of fresh-frozen sections at −30° C in the cabinet of the cryostat, for up to 24 h, had little effect on enzyme activity.
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