Dear Evelyn 

I suppose it could be possible that the periodic acid
could break down, leaving iodine precipitates on the
section. This may occur with old solutions (though I
have not seen it) or if staining is performed on a
staining rack and the solution breaks down due to, for
example, light or drying. 

I regularly do alcoholic PAS stains for glycogen and
mucin on ethanol fixed smears ( water is suspected of
washing these substances out of alcohol fixed smears)
and I have noticed that 1% periodic acid in 95%
ethanol does discolour to a brown after several weeks
standing at room temperature. I have not noticed the
precipitate though since I dispose of the solution
when it appears thus.


I still haven't heard though whether it is a PAS stain
or is it a "brilliant" H&E as one netter has described
it. Maybe we may soon know!!!
Tony

--- "Ms. Evelyn Kaplan"  wrote: >
Tony,
> Thanks for your reply.
> I have always thought that the formula for periodic
> acid was HIO4 and I
> hadn't really thought  the iodine came out of
> solution during the reaction;
> I take it that is what you are inferring. If so why
> don't our sections go
> red/brown, as in the case of carrying out an
> iodine/hypo step to remove
> mercury pigment? Also, is it the iodine then which
> acts as a the oxidiser?
> Evelyn
> 
> ----- Original Message -----
> From: "Tony Henwood" 
> To: "Ms. Evelyn Kaplan" 
> Sent: Monday, March 04, 2002 5:42 AM
> Subject: Re: do you recongize this?
> 
> 
> > Evelyn,
> > The molecular formula for periodic acid is H5IO6.
> This
> > where the iodine comes from.
> > Tony
> >
> > --- "Ms. Evelyn Kaplan" 
> wrote: >
> > Hi Tony,
> > >
> > > I am interested to hear your PAS method which
> > > includes iodine.
> > >
> > > Regards,
> > > Evelyn Kaplan
> > > Sultan Qaboos University,
> > > Oman
> > > ----- Original Message -----
> > > From: "Tony Henwood"
> 
> > > To: "Haines, Ashley N."
> > > ; "Histonet
> (E-mail)"
> > > 
> > > Sent: Wednesday, February 27, 2002 3:48 AM
> > > Subject: Re: do you recongize this?
> > >
> > >
> > > > Ashley,
> > > > The stain looks like a PAS.
> > > > Therefore is it iodine crystals from the
> Periodic
> > > > acid?
> > > > Otherwise, I'll keep mulling over it!!
> > > >
> > > > Tony
> > > >
> > > >  --- "Haines, Ashley N."
> > > 
> > > > wrote: > Can anyone help me identify this
> > > artifact??
> > > > >
> > > >
> > >
> >
>
http://people.clemson.edu/~ashleyn/images/artifact%20100x%20small.jpg
> > > > >  They
> > > > > look like little fleas in my sections.
> > > > >
> > > > > Thanks!
> > > > >
> > > > > Ashley N. Haines
> > > > > Dept. of OCBS
> > > > > Univ. of Md. Dental School
> > > > > 666 W. Baltimore St.
> > > > > Baltimore, MD 21201
> > > > > 410-706-7675
> > > > >
> > > > >
> > > >
> > > > =====
> > > > Tony Henwood JP BAppSc GradDipSysAnaly CT(ASC)
> > > > Laboratory Manager
> > > > Histopathology Department
> > > > The Childrens Hospital at Westmead
> > > > Locked Bag 4001
> > > > WESTMEAD, 2145
> > > > AUSTRALIA
> > > >
> > > > http://movies.yahoo.com.au - Yahoo! Movies
> > > > - Vote for your nominees in our online Oscars
> > > pool.
> > > >
> > > >
> > >
> >
> > =====
> > Tony Henwood JP BAppSc GradDipSysAnaly CT(ASC)
> > Laboratory Manager
> > Histopathology Department
> > The Childrens Hospital at Westmead
> > Locked Bag 4001
> > WESTMEAD, 2145
> > AUSTRALIA
> >
> > http://movies.yahoo.com.au - Yahoo! Movies
> > - Vote for your nominees in our online Oscars
> pool.
> >
>  

=====
Tony Henwood JP BAppSc GradDipSysAnaly CT(ASC)
Laboratory Manager
Histopathology Department
The Childrens Hospital at Westmead
Locked Bag 4001
WESTMEAD, 2145
AUSTRALIA

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