pubmed-article:781255 | pubmed:abstractText | Two methods are described for fracturing unfixed, uncryoprotected mouse liver that had been frozen by contact with a copper block at liquid nitrogen temperature. The best method involved precise fracturing of a few microns of surface tissue with a cooled glass knife, using the Cryokit attachment of the LKB III ultramicrotome. The resulting replicas were free from electron microscopically-visible ice crystals. A noticeable feature of replicas from unfixed, uncryoprotected tissue was the extent of plastic deformation of certain cellular structures. Cytoplasmic macromolecules, and to a lesser extent intramembranous particles, often appeared to be 'stretched' to form fibrils. | lld:pubmed |