The artifacts you describe are due to slow freezing, with
formation of ice crystals in the muscle fibres. 

You must freeze an unfixed specimen very quickly, either with
isopentane cooled by liquid nitrogen or with acetone cooled by
solid carbon dioxide.

-- 
-------------------------
John A. Kiernan
Department of Anatomy and Cell Biology
The University of Western Ontario
London,   Canada   N6A 5C1
   kiernan@uwo.ca
   http://publish.uwo.ca/~jkiernan/
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8#227#e8#227#e wrote:
> 
> Dear all histoneters,
> I am doing IHC on mouse muscle recently. At the beginning of doing the work, I
> embedded the tissue directly in the OCT on a mold at negative 20 dgeree. I had
> bad morphology with space between muscle fibers and most of the muscle cell
> have a big hole in the middle while inspected under microscope. After I read a
> lot of histonet archive, I used LN2 to snap frozen muscle tissue. The
> morphology of the tissue improved but there still got big holes in muscle
> cells. I used Aceton as fixative after frozen section. I tried Zamboni#161#Os
> fixative to fix sections for 20 minutes the other time, but unfortunately I
> still got urgly results. I thought the reason was poor fixation of the
> section. But I was afraid of using PFA would damage the antigenicity of the
> tissue. Are there any other fixatives which can preserve the antigenicity well
> enough I can use? It was a shame to say, I had spend almost one month on it.
> It was bottle neck whick stop my work go ahead. Would you histoneters give me
> some advice. If it is necessay,
> Any idea will be appreciated.
> 
> Baowei Peng
> Shanghai JiaoTong University,
> P.R.C.
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