We have recently undertaken a project which required a portion of muscle
to be analysed for fibre type and oxidative capacity.  The technique we
adopted to freeze the muscle (human muscle), was to mount the muscle on
cork using 'gum tragacanth', and then freezing this in isopentane cooled
in liquid nitrogen.  The trouble we're having is that every 5th sample
(roughly speaking) has ice crystal artifact through it.  I am
attributing this to the isopentan not being cold enough.  I guess my
questions therefore are:

1. Is there a way to protect the muscle from the freezing process, i.e.
putting O.C.T. over the muscle?
2. If the muscle has to be frozen in isopentane, what 'set up' has
worked for other people (i.e. we put the isopentane in a long metal
cylindrical container, inserted in a larger container holding liquid
nitrogen) and what techniques have you found useful (e.g. hold in
isopentane for 20 seconds)?

Any help (or small tips) would be very much appreciated!

Thanks in advance,

Tim Fairchild.
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Timothy J. Fairchild B.Sc. (Hons)
PhD Candidate
Co-ordinator for Centre of Athletic Testing
Department of Human Movement and Exercise Science
Nedlands, Western Australia 6907
Telephone: (+61 8) 9380 2793
Facsimile:  (+61 8) 9380 1039
Email: timf@cyllene.uwa.edu.au
http://www.general.uwa.edu.au/~hmweb/index.htm