[Histonet] Finding iron in decalcified sections

[Lee & Peggy Wenk]

Acid decalcifiers will remove some to all iron.

Don't use Bouins - picric ACID and acetic ACID will start the
decalicification process, and will definitely remove small amounts of iron.
Use the NBF.

Can you switch to a milder decalcifier for a longer time? 
- FASC = formic acid-sodium citrate
- EDTA

The Bancroft book has the procedures for these. If you need them, let me
know.

Now, with that said, I have a question - what type of iron is it? I know the
Prussian Blue iron stain will demonstrate hemosiderin, with ferric ions (FE
+3) in the center. And that hemosiderin also contains ferritin, which is a
ferric ion (FE +3) protein complex. Prussian blue will demonstrate ferric
chloride (Fe +3 ions) when put in goblet cells for the Colloidal iron stain.
But Prussian blue will not stain the iron bound in RBC in the form of
hemoglobin. That iron is bound to oxygen and proteins, and isn't available
for Prussian blue staining. 

So, I don't happen to know (and would love to learn) what type of iron is in
chicken beaks. Is it iron metal filings (no charge, and I'm guessing
probably won't stain with Prussian blue), or iron ions but bound to proteins
and/or other chemicals that won't stain with Prussian blue? Or is it the
type of ferric ion that is available for Prussian blue staining? Or is there
another technique that's going to be used to demonstrate the iron?

(I love HistoNet. Get to learn new things every day!)

Happy National Medical Laboratory Professionals Week!

Peggy A. Wenk, HTL(ASCP)SLS
Beaumont Hospital
Royal Oak, MI 48037

-----Original Message-----
From: histonet-bounces <@t> lists.utsouthwestern.edu
[mailto:histonet-bounces <@t> lists.utsouthwestern.edu] On Behalf Of Farish,
Craig
Sent: Wednesday, April 22, 2009 7:14 PM
To: histonet <@t> lists.utsouthwestern.edu
Subject: [Histonet] Finding iron in decalcified sections

Hi folks - I'd very much appreciate some help with this problem. I've been
asked to performing the routine histo for a trial investigating the ability
of chickens to sense direction. They are believed to have areas of iron rich
tissue in their beaks which can detect the magnetic field of the earth in
the same fashion as homing pigeons. The problem is this
- to section the beaks I need to decalcify them, however I'm pretty sure
that standard decalcification removes iron, at least partly. I know that the
levels of iron in the tissue are very low and I've just trialled my
technique on a pigeon with no success. I'm using a standard Perl stain (2%
HCl + 2% K Ferrocyanide for 20 mins) on FFPE tissue which usually works very
well for me, fixation is for a minimum of 24 hours in either 10%NBF or
Bouins and decalcification is in either 5% Nitric acid or formic acid. Would
anyone have any suggestions as to how to decal without removing iron or
another stain which I could use in this situation?

Thanks in advance for any and all suggestions,

Craig 

 

Craig (Joe) Farish

Senior Technical Officer

Veterinary Diagnostics

School of Animal and Veterinary Sciences

Charles Sturt University

Wagga Wagga, Australia

c farish <@t> csu.edu.au

 

' I don't want to achieve immortality through my work, I want to achieve
immortality through not dying' - Woody Allen

 

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