[Histonet] RE: Frozen storage of tissue and sections, what is the correct temperature?

[C.M. van der Loos]

   Dear Kelly,

   We always store our (unfixed) cryosections at -80C. IHC staining is
   successful up to years of storage in this way. In the past we used to
   store at -20C and this resulted into a loss of specific epitopes like
   CD25, CD4, CD3 in just a matter of weeks. Don't do this!

   If you have dried your specimens completely (as you did for a
   few hours at room temperature) there is no chance that ice-crystals
   influence the tissue morphology, simply because there is no water
   left!


   ----- Original Message -----
   From  Kelly D Mcqueeney <kelly.mcqueeney <@t> bms.com>
   Date  Thu, 17 Feb 2005 11:52:36 -0500
   To  histonet <@t> lists.utsouthwestern.edu
   Subject  [Histonet] Frozen storage of tissue and sections, what is the
   correct temperature?

   I know that frozen tissue storage is a common topic, but I have a hard
   time finding the right answer throughout the histonet archives.
   We are currently coating brain in embedding medium and snap freezing
   brains in isopentane followed by immediate storage at -80C. Then, we
   bring the brain up to -20C a few hours before sectioning. After
   sectioning,  we  dry  the  slides at RT for several hours and store at
   -80C
   until using the tissue for ligand binding,  IHC or insitu. This exact
   protocol has been moderately successful, so far so good. But, some of
   the  staff  store  frozen  brains  at -20C. They feel that keeping the
   tissue
   at cryostat temperature reduces the amount of freeze artifact. I was
   always   taught   to  freeze  fresh  frozen  brain  at  a  much  lower
   temperature.
   None  of  this  has  been  tested  in  our  lab.   Any suggestions for
   long-term
   storage of whole brains after collection? Is -80C the correct
   ! temperatu