RE: storage frozen tissue -80C
|From:||Chris van der Loos (by way of Histonet)|
To my opinion, the storage of cryostat tissue sections is something
different as storage of frozen tissue blocks.
After cutting a cryostat section you let it dry for a while. Upon storage
you don't want to let it become wet again. However, I don't understand the
use of silacagel for keeping your cryostat sections dry. I think this is
quite overdone because the environment in your -80C freezer is already as
dry as the dessert. Remember how dry your skin starts feeling when only -10C!
A frozen tissue block still contains a lot of (frozen) water. You don't
want to let it dry out (freeze-drying effect; the white spots at meat as
you described). For this reason, you need to put a few drops of water into
the cryotubes next to your tissue block for real long storage at -80C.
After closing the cryotube, the frozen water ensures a certain (very low)
vapor pressure, preventing the tissue block from freeze-drying effects.
I hope this contributes to solving your dilemma.
Chris van der Loos
Academic Medical Center
Dept. of Cardiovascular Pathology
Amsterdam, The Netherlands
>Date: 5 Mar 2003 09:20:54 -0600
>From: Frouwke Kuijpers
>Subject: storage frozen tissue -80C
>I have a question about storage of frozen tissue.
>We have no experience with that and we are forced to it now because the mice
>which we use for our experiments are sick and it takes at least a year
>before we can get new ones. So we have to be very economical with the tissue
>we have left. We have the fixed sections now in autoclaved PBS and So-azide
>at 4 C.
>People suggested we can store the left sections at - 80 C after mounting
>them on slides. I have read about it in the archives of the Histonet and
>most people advice to put silicagel in the slide boxes to prevent the
>sections become too humid. Is that for the ice crystals?
>But now my problem: other people of our University told me to put wet tissue
>in the slideboxes, to prevent the sections are drying out? (Those white
>spots you see when you left your frozen meat too long in the fridge).
>So, I am in a dilemma now, I have two complete opposite advices, what should
>Dept. Cellular Animal Physiology
>University of Nijmegen
>6525 ED Nijmegen
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