Dear Margaret,

Re-freezing thawed tissue is one of histology's great dilemmas.  What we do is
unthaw the tissue, gently take the tissue out of the OCT or whatever embedding
medium you are using, fix in 10% buffered formalin, process on our regular
processing schedule, embed tissue in paraffin.  If you attempt to embed in OCT
and do frozen sectioning, you will have ice crystals in the tissue because of
the re-freezing of the water molecules.  If you have a good processing
schedule and paraffin embed, your tissues will come out looking great.

Tom Galati
Histo-Scientific Research Labs.
(540)856-2222
107 Killmon Road
P.O. Box 30
Basye, VA  22810
histosci@shentel.net










Margaret Gondo wrote:

> Hi Folks!
>
> Here's the "stupid" question of the day that I hope you all can answer.  I
> have some muscle tissue which I had frozen using standard techniques (ie
> gum tragacanth, pre-cooled isopentane in liquid nitrogen).  Due to some
> questions which have popped up regarding the possibility of infectious
> agents being present, I am now being persuaded to formalin fix these same
> tissues.  I shrudder to think what these tissues are going to look like
> after I'm through thawing, fixing, processing, ect.  Any suggestions as to
> how I can do this with the minimalist damage?  Any advice as to what I
> should expect my tissue to look like after I'm through?
>
> Thanks a bunch!
> Margaret