[Histonet] Mouse Tissue Problem

[judi.ford <@t> jax.org]

Hi Everyone,

Our lab has encountered a problem with a batch of mouse tissue processed recently. We receive tissue from various research labs and it is usually either fixed in Telly's or Bouin's for 24 hrs before processing. Nothing unusual was noticed until facing this batch of blocks. Some blocks faced fine while others, like muscle and tumors, shredded and the tissue was soft and spongy (light colored in the middle).  The blocks I have faced fine and were hydrated on an ice tray prior to sectioning.  In the past I've hydrated bouin's fixed blocks for a couple of days and never had a problem with cutting.  These blocks were hydrated in the frig overnight, which is my usual pattern, and then cut the next day.  I'm having a horrible time cutting the tissue. Intestines (not impacted with feces) are not cutting well (very compressed with a new knife) and the tissue breaks away from the paraffin both in the block and on the waterbath. The surface of the faced tissue appears wavy after hydration. My water bath temperature is 40 degrees centigrade.

We've been discussing the following as possible causes: inadequate fixation, fixative mixed wrong, inadequate levels of solutions in the processor (although tissue on the top layer came out fine), tissue not cleared properly, etc. 

I hoping someone may have some ideas on how to narrow down our troubleshooting with this problem.

Thanks in advance.

Judi Ford
HIstotechnologist
The Jackson Laboratory
Bar Harbor, Me  04609