Re: [Histonet] storage of cryosections

From:Gayle Callis


Initially, how you snap freeze is the first defense against freezing 
artefacts. Frozen section stored with a dessicant is a good idea  keep the 
sections dry during storage.  The storage container must stay closed to 
equilibrate FS to room temperature.  Water condensation is the enemy.  Be 
sure to air dry the sections before going into storage also.  A black 
plastic 25 slide capacity box works well.   Also, opening a box directly 
from freezer and taking a few sections out, then returning unused sections 
to freezer must be avoided due FS freeze thaw.  Put as many slides as you 
need per storage container for a staining session.

Drierite is anhydrous calcium chloride and has a tendency to exfoliate fine 
CaCl2dust all over everything including your sections which bothered 
me.   Try 10 to 18  mesh silica gel, (Fisher#  S161-500).  The little beads 
have blue indicator so you know when dessicant is depleted.  Put Silica gel 
in a nylon processing bags (Thermo Electron or StatLab) or embedding bags 
aka tea bags from Fisher, fold over top, and staple on fold the keep bags 

Temperature is critical for storage - if you have -80C available, use that 
instead of -20C, and NEVER store sections in a self defrosting freezer 
found in a refrigerator, freeze dry cycle is very damaging.  Hopefully you 
can store FS at temperature lower than
-20C to preserve antigenicity over a long period of time.  It may work for 
short term storage and robust antigens.

At 02:23 PM 12/13/2004, you wrote:
>Do I actually have to add Drierite absorbent into the boxes with the cryo
>sections in the -20C freezer to avoid freezing artefacts?
>Thanks, birthe
>Histonet mailing list

Gayle Callis
Research Histopathology Supervisor
Veterinary Molecular Biology
Montana State University - Bozeman
PO Box 173610
Bozeman MT 59717-3610
406 994-6367 (lab with voice mail)
406 994-4303 (FAX)

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