Embed them completely and keep them in airtight vials (suitable for freezing,
e.g. Nunc cryovials or similar) to prevent freeze drying. The very best
practise is to immerse blocks under liquid nitrogen, but -70 is still very
efficient. If you section a block and want to retain it for further sections at
a later date, cover the cut surface with OCT and allow it to freeze prior to
storage, having said that recuts of frozens are often not as good as the
originals. It depends on the tissue.
I hope this helps.
Margaret
Unilever Research
Beds
UK

-----Original Message-----
From:	Michael Stumm [SMTP:stumm@ubaclu.unibas.ch]
Sent:	Wednesday, September 22, 1999 5:25 PM
To:	histonet@pathology.swmed.edu
Subject:	long time storage of frozen tissue

Dear Histonetters

 I would like to keep collected tissue specimens in a -70#176#C fridge in order
to make frozen tissue sections on demand. Can you provide me with some
comments about methods for long time storage of frozen tissue specimens?

Thank you.

Michael

Michael Stumm, MD, Lab 405
Department of Research
Kantonsspital Basel
Hebelstrasse 20
4031 Basel
Switzerland
phone: ++41/61/265 23 84
email: stumm@ubaclu.unibas.ch