Thank you for your response. Unfortunately we are required by Neurotoxicity
guidelines to perfuse- fix in Glutaraldehyde since all the peripheral nerves
are processed to resin for 1 micron sections. It's only the brains though
that are giving problems. I agree with you that poor wax penetration seems
to be the cause. This doesn't seem to affect the transverse sections of
gastrocnemius muscle or the eyes in these studies. I was wondering about
trying some different clearing agents. At present we use Toluene. Any
further suggestions would be gratefully received.
Rita  Russell.

> ----------
> From: 	J. A. Kiernan[SMTP:jkiernan@uwo.ca]
> Sent: 	09 July 2001 21:02
> To: 	Russell Rita GBAP
> Cc: 	histonet@pathology.swmed.edu
> Subject: 	Re: Gluteraldehyde fixation.
> 
> On Mon, 9 Jul 2001 rita.russell@syngenta.com wrote:
> 
> > I am currently experiencing problems with sections of rat brain
> following
> > perfusion fixation with Modified Karnovsky's fixative. They are proving
> very
> > difficult to flatten. I think the main cause is inadequate paraffin wax
> > impregnation following an overnight schedule.
> 
> Glutaraldehyde fixation makes sectioning in paraffin
> difficult. The usual explanation is that the abundant
> cross-links among protein molecules impede penetration
> of the wax molecules. Longer times in melted wax
> might help. If it doesn't, you could cut frozen or
> cryostat sections instead, or fix in a mixture that
> doesn't contain glutaraldehyde. There are very few
> circumstances in which glutaraldehyde fixation is
> necessary for subsequent light microscopy.
> ----------------------------------------
> John A. Kiernan
> Department of Anatomy & Cell Biology
> The University of Western Ontario
> London,  Canada   N6A 5C1
>    kiernan@uwo.ca
>    http://publish.uwo.ca/~jkiernan
>