Gentle Jane freezing

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From:"Instrumedics, Inc." <>
To:HistoNet Server <>
Content-Type:text/plain; charset="iso-8859-1"

I am sorry that about my  poor choice of words. I was not referring to
freezing for EM,
when I used the term "amorphous" ice. EM  studies require much better
freezing than for LM. We called the device Gentle Jane as a play on
Gentleman Jim, a device used to freeze specimens for EM. Many of you in EM
work may remember Gentleman Jim!  With Gentle Jane we freeze with a 3/4 lb
heat extractor that is chilled in liquid nitrogen to -196deg. C. The heat
extractor is chrome plated and the bottom surface is mirror finished which
makes it a very efficient conductor. The heat extractor falls at a
rate so that is does not crush the tissue when it makes contact. It isn't
Gentleman Jim
slam freezing as for EM.  We also recommend that the tissue to be frozen be
1-2mm thick if possible.
It is absolutely true that the results with the Gentle Jane are generally
not adequate for EM, beyond a depth 20 microns. Some users of the
tape-transfer technology(CryoJane) have been able to cut 2 micron sections
within the first 20 microns and have indeed had close to EM quality ice in
their frozen section. However, generally, the trimming step removes the
first 20 microns and the ice crystals are larger, but often small enough not
visible at the LM level. That is why the morphology is well preserved.

I am sorry for any inaccuracies in my earlier message.


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