[Histonet] Histonet Digest, Vol 157, Issue 21 the center

[Steve McClain]

What paraffin are you using?
I heard a rumor one manufacturer changed formulations recently. Same brand name different formula. 

Center problems often  manifest where  insufficient fixation is a primary event or where rapid processing meets the limits of solution maintainance and tissue size. Rapid processing w inadequate alcohols is a silent offender. Sometimes you just replace every solution, just so you know where you a new starting point. 

If you suspect a processing problem as a cause, one can often achieve a better result by melting and re-embedding in new paraffin. By this I mean Allow to sit in the embedding center melted in a new mold, in fresh new paraffin for 60minutes. Then Change paraffin again and embed and cool. Not sure why it works, but cooking for a few more minutes does.improve sectioning in marginal tissues.

Pathologists can also be the cause- Tissues which are crushed have aberrant staining patterns. 
XS handling prior to fixation can mess up staining. Raw tissues rushed through and on the processor. I am guilty of all of them in the past.

Steve A. McClain, MD


> On Dec 28, 2016, at 13:30, "histonet-request at lists.utsouthwestern.edu" <histonet-request at lists.utsouthwestern.edu> wrote:
> 
> Our pathologists are complaining that the center of tissues are not
> staining properly in both our H&E's and IHC's. Can anyone provide some
> thoughts as to where this problem could be occurring?
> 
> 
> As a separate situation we are experiencing the tissues folding or falling
> off during the staining process. Both this issue and the staining issue are
> recent occurrences and we have not changed our process in any way from
> previous years.