Abstract
In the paraffin-agar sandwich method, which is a new cell block manufacturing method, we focus on the known fact that the agar added during the preparation process disappears from the specimens for immunohistochemistry after heat treatment. To remove the agar that may interfere with the observation of hematoxylin-eosin-stained specimens, the temperature and heating time at which the agar disappears were quantified, and the amount of residual agar was compared. Results showed that at 98°C, there was a difference in the number of residual agar between the start of heating at 0 minutes and after 10 minutes of heating or later and between after 0.5 minutes of heating and after 15 minutes of heating or later. Furthermore, comparison of the number of residual agar between heating at 80°C and that at 90°C showed that after 60 minutes of heating, the maximum degrees of decreases were 15% at 80°C and 50% at 90°C, whereas at 98°C, a decrease of 99% was observed after 0.5 minutes of heating, which remained constant at 0.05% or less after 15 minutes of heating. From the above results, it was shown that the temperature required for the complete melting of agar was 98°C, and the shortest time for the complete melting of agar was 15 minutes after heating. In this paper, we will also report changes in the preparation procedure and new findings obtained from the first report.
