Re: [Histonet] Frozen section ...HELP

[Lee Peggy Wenk]

The freezing point of water is 0 degrees C. The freezing point of 100% 
ethanol is -114 degrees C. The freezing point of 70% alcohol is about -48 
degrees C. Since most cryostats are at -20 to -25 degrees C, your tissue 
isn't freezing completely. You probably have slush ice inside the cells. 
Not hard enough to support the tissue during a frozen section.


Fresh tissue would be the best, as formalin fixed tissue also tends to cut 
awful (whole different reason). If you can't get fresh tissue from human or 
animal necropsy, can you get some parts from a raw uncooked chicken to 
practice on? Save some muscle, skin, liver, etc., from tonight's supper?


Peggy A. Wenk, HTL(ASCP)SLS
Beaumont Hospital
Royal Oak, MI 48073

--
From: louise renton louise.ren...@gmail.com
Sent: Monday, November 08, 2010 4:43 AM
To: Histonet Histonet@lists.utsouthwestern.edu
Subject: [Histonet] Frozen section ...HELP


Hi all,

after more than a decade of NOT cutting frozen sections, I find myself
back at the ice-face.
To get my hand in (not literally) I thought I would do some trial
sections on stored tissue - stuff that was in formalin and now in 70%
alcohol.

Horror ; dismay. The tissue, once frozen, is all mushy in the middle.
Is this because of teh long storage?

is there anything I can do to improve the situation?

much appreciated

--
Louise Renton
Bone Research Unit
University of the Witwatersrand
Johannesburg
South Africa
+27 11 717 2298 (tel  fax)
073 5574456 (emergencies only)
There are nights when the wolves are silent and only the moon howls.
George Carlin
No trees were killed in the sending of this message.
However, many electrons were terribly inconvenienced.

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RE: [Histonet] Frozen section ...HELP

[Monfils, Paul]

Hopefully you removed the antifreeze (alcohol) before freezing? :-) I
have run into this a few times. I work in a core facility where people
send me samples from all over.  Recently someone sent me some samples
fixed in Histofix, which is a commercially available aqueous fixative.
But they neglected to tell me they add 15% ethanol to the commercial
solution.  I froze all the samples in OCT compound, but they could not
be sectioned.  I had to melt them all, soak them in several changes of
buffer for several hours to remove the OCT and the methanol, then put
them in fresh OCT and refreeze them.  And that was only 15% alcohol, not
70%!



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