Abstract
Several solutions must be formulated immediately prior to their use for special staining, a representative stain being naphthol ASD chloroacetate esterase (NASDCAE), because the solution for NASDCAE staining is quickly inactivated. In order to perform a more convenient and stable NASDCAE staining, we have examined and explored new methods. A freshly prepared solution for NASDCAE staining was aliquoted and rapidly frozen using a cryogenic refrigeration system, followed by long-term storage at −75°C. A comparison between the one-year frozen solution and the conventional solution for NASDCAE staining revealed that a good staining capacity for bone marrow specimens was retained even when using the rapidly frozen solution. However, a gradually frozen reaction solution, as well as a frozen solution but not freshly prepared, lost their activities. Staining with an unfiltered and rapidly frozen solution showed much better resolution than that with a filtered solution. Thus, the method described herein makes it possible for laboratory technicians to perform a simpler and more stable NASDCAE staining. We also examined whether this rapid freezing method is applicable to other stains that require fresh formulation immediately prior to the staining procedure. Finally, we demonstrated that this method is useful not only for Watanabe’s method for reticulum staining but also for acetylcholinesterase staining.
