-35 may NOT be cold enough for cryosectioning fat. That is probably why 
there are holes where fat comes out of OCT as the fat is just too soft, not 
in a truly solid state. Try cooling the block and knife with dry ice to 
lower the temperature further and see if that helps.  Be sure to not give 
yourself frostbite.

  We were able to cut mink skin which contains almost pure mink oil for the 
purpose of seeing hair follicles, the lipid was basically liquid using 
Intrumedics tape transfer.  The fatty parts of skin really did not stay on 
the tape very well but hair follicles were glued down nicely.  I know one 
hospital laboratory who used this instrumentation to cut frozen sections of 
fatty human breast with success.

Before thawing and trying to fix the fat, go to colder temperature instead.

At 08:12 PM 3/14/2005, you wrote:
>Hi all:    I have a project that the researcher wants
>frozen sections on mouse fat for immunofluorescence.
>I froze mesenteric and epididymal fat at necropsy in
>isopentane.  I am having a hard time getting the
>tissue to cut-I'm getting the hole in the middle of
>the OCT block.  I have changed the temp in the
>cryostat to range from -16 to -35 and inbetween to see
>if colder would help.  Not much luck. Does anyone know
>if I can defrost and fix the tissue and will it
>improve the cutting or will that cause it to loose any
>FITC. Thanks for any suggestions.  Pam
>
>
>
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