Hello Kathie,

Having the paraffin melt around the tissue is usually not a problem; however, the effect of heat on protein antigenicity 
can be determined empirically only.  I've performed experiments where melting the paraffin was quite acceptable and 
other experiments where a particular epitope (or the antibody-antigen binding complex) was "destroyed" - well, at least 
modified enough such that the antibody could not bind well enough to create an observable signal.

If the student's tissue block is not completely used up, could you not produce more sections and not warm them as 
much (or at all)?  This could be a useful pursuit in illustrating the concept of optimizing experimental conditions.  By 
adding a few slides to the study you might be able to demonstrate the effect of changing one variable in your 
procedure.  The result could be "no significant effect", "significantly positive effect", or "significantly negative effect" 
and teach some valuable lessons in experimental procedure.

At any rate, good luck with your study and let us know your results.

Regards,
Todd Sherman

t-sherman@home.com

8/6/2001 10:21:40 AM, Kathie Berghorn <kab35@cornell.edu> wrote:

>Dear Histonetters,
>	I am relatively new at using paraffin sections -- I had a 
>student cutting paraffin sections over the weekend and to 'help' 
>sections dry on the slide warmer after cutting, turned up the slide 
>warmer enough that it melted the paraffin around the tissue.
>
>	My question is.... is the tissue still usable?  Did the heat 
>damage proteins within the tissue affecting the antigenicity?
>
>	Thankin