Cocco C, Melis GV, Ferri GL. Embedding media for cryomicrotomy: an applicative reappraisal.
Appl Immunohistochem Mol Morphol 2003;
11:274-80. [PMID:
12966356 DOI:
10.1097/00129039-200309000-00012]
[Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
We reassess here the formulation of cryoembedding media in connection with recent developments in commercial cryomicrotomes. Water-based solutions of polyvinyl alcohols were our starting media, and each of 2 different polymers (56-98, MW approximately 195000; and 6-98, MW approximately 47000) showed a critical concentration for optimum sectioning. At higher or lower polymer concentrations, wrinkles and folds became apparent in tissue areas of sections, or in the sectioned embedding medium areas between tissues, respectively. Addition of polyethylene glycol (MW 380-420) further facilitated and improved sectioning, resulting in frozen tissue blocks that cut well in the 2 to 100 microm range and further, using disposable blades throughout. Applying a wide temperature differential between tissue specimen (-11 degrees C to -13 degrees C) and cutting knife (-33 degrees C to -35 degrees C), serial adjacent sections were reproducibly obtained at a 2-microm setting, singly or in short ribbons. Embedding media of low and high viscosity were obtained, depending on the polyvinyl alcohol polymer used, and could be applied sequentially for tissue infiltration followed by embedding with precise sample orientation. When required, media were made semisolid by addition of carboxymethylcellulose.
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