[Histonet] lead, barium detection

[John Kiernan]

Lead and barium should end up as their insoluble phosphates in tissues fixed in phosphate-buffered formaldehyde.
 
There are published methods (Pearse's Histochemistry 4th ed Vol 2 [1985]; also in earlier editions, not much different). According to DJ Cook "Cellular Pathology" 2nd ed. Scion 2006, p.174, "It is rare that there is sufficient lead in a normal person to be detectable by histochemical methods. The most sensitive method of detection is the sodium rhodizonate method, which produces a red chelate with lead ions." Barium, strontium and mercury also have red complexes with rhodizonate. Lillie & Fullmer "Histopathologic Technic" 4th ed (1976) pp.547-8 suggest prior treatments to remove salts of Ba and other metals, and adjustment of pH of the rhodizonate solution to enhance specificity for certain metals. My limited experience of staining with rhodizonate for Pb in lab animal tissues (long ago) was rather disappointing, with the result being brownish rather than bright red. 

I suspect that histochemical staining with rhodizonate for exogenous metals like Ba, Pb, Hg etc is mainly a histochemical curiosity, or am I mistaken?  If anyone reading this has significant experience with rhodizonate I would urge them to publish an account, with hints on how to obtain good results every time. I'm sure the Journal of Histotechnology or Biotechnic & Histochemistry would appreciate a good paper on the subject! 
 
John Kiernan
Anatomy, UWO
London, Canada
= = =
----- Original Message -----
From: Lynette Pavelich <lpaveli1 <@t> hurleymc.com>
Date: Tuesday, August 25, 2009 10:23
Subject: [Histonet] lead, barium detection
To: histonet <@t> lists.utsouthwestern.edu

> Hello Histonet,
> Our CSI pathologist wants to detect lead or barium in autopsy tissue
> already fixed in 10%NBF. Do any of you have any good 
> staining methods
> you could share?
> 
> thanks alot,
> Lynette
> 
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