Re: hard tissue

From:Gerard Spoelstra

John, I'll try and offer a clearer explanation of my case for the use of 
the fabric softener to improve the processing of bone and other hard tissue.

Gayle Callis in her chapter on Bone in  the 5th edition of Bancroft's 
Theory and Practice of Histological Techniques states "Oversize thick bone 
slabs require an extended processing schedule to obtain adequate 
dehydration, clearing and infiltration". We have found vastly improved 
results in the cutting properties of hard tissue : bone, horses hoof; which 
is very compact keratin( this required extended times in the softener), 
fatty tumours and mammary tumours.

A fabric softener is essentially a detergent or surfactant which lowers the 
surface tension of water. Several mechanisms in which the water softener 
may contribute to tissue processing of hard tissue:
  By lowering the surface tension of the water in the tissue it could 
improve the flow of water through the tissue.
  It could also facilitate the  removal of water-soluble lipids from the 

Prior to incorporating the pre-processing  softener step to our hard 
tissues, we would observe a patchy whitish appearance to our hard tissue 
blocks, consistent with inadequate processing.

We use a fabric softener commonly used for clothes, available here in 
Australia from all supermarkets.

At 01:00 AM 21/03/03 -0500, you wrote:
>This reply begs many questions. Here are a few.
>1. Is there a missing bracket somewhere in "(after
>   decalcification with a domestic fabric softener ..."?
>     (Yes I know, it's nit-picking; the right bracket
>      after "decalcification" got lost in the aether...)
>2. Which fabric softeners are surfactants?
>3. How can a fabric softener (or a surfactant)
>   improve "the dehydration of the tissue?"
>   Equilibration with 100% alcohol must surely
>   replace all the water in any object. Dehydration
>   has to be complete for paraffin embedding. Where
>   is the room for "improvement?"
>4. Can you explain, "... bone used to swell on the
>   watery clearing demonstrating that there was
>   inadequate processing."  Every dehydrated object,
>   be it a walnut or a 5um or a 100um section, swells
>   when in contact with water.
>John A. Kiernan
>Department of Anatomy and Cell Biology
>The University of Western Ontario
>London,   Canada   N6A 5C1
>Gerard Spoelstra wrote:
> >
> > We treat all our our hard tissue including bone(after decalcification with
> > a domestic fabric softener prior to processing. We leave the tissue for a
> > hour in 1-5% fabric softener. This works very well. The problem with hard
> > tissue is that you need much longer processing times to get adequate
> > paraffin infiltration. The softener acts as a surfactant improving the
> > dehydration of the tissue. In the time before we started to use softener,
> > bone used to swell on the watery clearing demonstrating that there was
> > inadequate processing. Its possible that if you used the surfactant for all
> > tissue other than hard tissue you may be able to bring down the processing
> > times drastically, but I haven't tried this.
> > Gerard Spoelstra
> > Medical Scientist
> > Veterinary Histology
> > Murdoch University
> > Western Australia


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