Deb,

Freeze artifact is that damage which is produced by the formation of 
large (big enough to be seen through the microscope) ice crystals.  This 
is physical damage which can rupture cells, move proteins and enzyme 
localization sites ad nausium....  and while thawing and refreezing may 
make the sections look better the actual damage to the cells is not 
undone.  I would also note that a tissue which is optimally frozen for 
light microscopy at say -80 would be almost useless for Cryo TEM.  Some 
time ago I posted some information about freezing rates which should be 
in the archives.

Robert Schoonhoven

WWmn916@aol.com wrote:

> 1) Does anyone know if skin that is misoriented, freeze 
> artifact....any other problems once frozen can be thawed and refrozen 
> again?  
>
> 2) Would thawing/refreeze affect the IF staining afterwards?  
>
> 3) If a skin has freeze artifact and if it can be thawed, does it need 
> to be rolled in talc powder before refreezing?  (Muscle biopsies that 
> are thawed/refrozen are rolled in talc powder to get rid of freeze 
> artifact.)
>
> I'm hoping for some quick, good advice before I address a problem at 
> work.
> Thanks to whomever can help.
>
> Deb King, HT (ASCP)
> Email:  WWmn916@aol.com