Equipment testing and tuning: the cold-knife cryomicrotome microm HM-560

A major innovative feature of the Microm HM-560 cryomicrotome is the independent control of specimen and knife temperatures. We used such equipment with a variety of tissues, and fixation and freezing procedures. High-quality sectioning was reproducibly obtained using 1) a low temperature setting for the sectioning blade ("cold knife," about -33 degrees C); 2) a comparatively high temperature for the specimen; and 3) a suitable mounting medium, which would remain solid up to about 0 degrees C. Specimen temperature was set between -8 degrees and -15 degrees C for 4-microm sectioning, higher temperatures (-1 degrees to -8 degrees C) being appropriate when cutting at 10 to 20 microm. Under such conditions, disposable blades were effective throughout, while a modified antiroll plate profile further enhanced usability. After intensive use for almost 3 years, by more than 15 different users, the cryomicrotome is in excellent working order.