This is not an uncommon problem with tissue that has been frozen very 
slowly.  I suggest you refer to Pearce Histochemistry Volume 1 page 23.  I 
found it a very interesting read.  This explained a phenomenon I had seen 
in  blocks of pancreatic tissue which had been placed in  Nunc tubes and 
thrown into, or rather on to, liquid nitrogen. The cells appeared very 
shrunken and the connective tissue had huge gaps between the fibres.  The 
3rd paragraph also made interesting reading.  If I understood what the 
Pearce had said it implied that ice crystal artefact could be  produced by 
freezing too rapidly which is contary to the percieved wisdom.   i have 
since looked at sections of tissue with ice crystal artefact and noticed 
that it is often seen around the edge of the block and not in the centre.

Would anyone like to comment?

--On 19 May 2001 07:23 -0400 WHudson436@aol.com wrote:

> I work with muscle bx's and often run into problems with specimen that
> arrive  frozen.  When they are still frozen and are packed in dry ice.
> One of the  most frustrating problems that occur with some of the
> specimens is after I  place the frozen specimen in the cryostat set at-20
> the muscle becomes soft  and "squishy."  I have placed them directly into
> the cryostat still frozen as  well as letting them come to room
> temperature and then snap freezing the  sample.  They still seem to get
> equally soft after they have been in the  cryostat.  The muscle acts as
> if something has caused it  to require a lower  temperature to keep it
> frozen solid. I do not run into that problem with the  muscle bx's that
> arrive fresh and that I snap freeze.
>
> Can any one suggest good reference books or web sites for established
> technique on muscle bx's.  I would be very appreciated of any and all
> hints  from techs who work with muscle bx's.
>
> Thank you so much.
>
> N. Hudson
>
>
>



Mrs.Wendy Prime
Experimental Officer
CTBRC
University of Liverpool
0151 706 4503