Re: [Histonet] Microwave Processing (Egg)

From:John Kiernan


The egg is stable for weeks, especially if
refrigerated. Boiling an egg solidifies the
proteins, especially the albumen (white).
This makes the egg easier to eat than the
liquid contents of a broken raw egg. Cooking
has enabled us humans to collect all the
fat and protein from the eggs we take from

Fixation means preserving structural detail 
for microscopy. Heat alone will not do that.

John Kiernan
London, Canada.
Kemlo Rogerson wrote:
> Um....... A boiled egg is stabilized but not fixed; does that help? A
> fixative is designed not only to stabilize proteins by coagulation, but
> in most cases it links chemically to the proteins. Its job is also that
> of preventing putrefaction both by endogenous and exogenous means
> (lysosomes and bugs). A boiled egg will rot by putrefaction, but if you
> fixed it, then it wouldn't; would it? Heat stabilizes by coagulating
> protein doesn't it, formalin forms links between reactive sites on the
> proteins, doesn't it?
> Am I talking a load of...........
> Mr Kemlo Rogerson MSc DMS MIBiol CBiol FIBMS
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> -----Original Message-----
> From:
> [] On Behalf Of Marshall
> Terry Dr,Consultant Histopathologist
> Sent: 21 April 2004 12:48
> To: Steven E. Slap; kevin williams;
> Subject: RE: [Histonet] Microwave Processing
> My confusion has not been dispelled.
> Steven writes:
> "The saline will not work
> alone as a fixation step, except in the case of
> very small biopsies (as written up in an article
> by Tony Leong)- ..."
> In the next post, we get:
> "Yes, in the Leong method for biopsies, the specimens are heat
> stabilized in the microwave in saline, and not really chemically
> fixed.  They get fixed in the ethanol in a traditional processor ..."
> These statements are mutually incompatible.
> Moreover, what is the difference between "stabilisation" and "fixation".
> A further muddle is introduced by:
> "not really chemically fixed."
> Well, hell, are they fixed or no? Heat fixation is fixation - who cares
> whether chemically fixed?
> Of course, the major problem is that mechanisms of fixation are varied
> (with the fixative) and not well understood.
> (Speak for yourself do I hear someone say?)
> Dr Terry L Marshall, B.A.(Law), M.B.,Ch.B.,F.R.C.Path
>  Consultant Pathologist
>  Rotherham General Hospital
>  South Yorkshire
>  England
> -----Original Message-----
> From: Steven E. Slap []
> Sent: 17 April 2004 22:54
> To: Marshall Terry Dr, Consultant Histopathologist; kevin williams;
> Subject: RE: [Histonet] Microwave Processing
> Hi Terry & HistoNetters
> I have done lots of successful large organ
> stabilization in saline at 65C for 20-35 minutes
> (depending on the size of the organ.  However, it
> is important to emphasize that the purpose of
> this step usually is to firm up the tissue so
> that it can be subsequently cut up into thinner
> pieces for processing, which must include a
> fixation step, either in the microwave or on a
> conventional processor, in formalin or some
> non-formalin fixative.  The saline will not work
> alone as a fixation step, except in the case of
> very small biopsies (as written up in an article
> by Tony Leong)-  a procedure I have not tried
> myself.
> best regards,
> Steven Slap
> Microwave Consultant
> At 3:58 PM +0100 4/16/04, Marshall Terry Dr,
>         Consultant Histopathologist wrote:
> >Sorry to but in - but on a related question -
> >does anyone do microwave fixation in saline as
> >described by for instance the Melbourne group,
> >which involves bringing up to 65C in saline?
> >Have tried it this week and the sections are even crummier than usual.
> >When I was in Tasmania, a local private lab. did
> >it and their sections were fine.
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