On Tue, 28 Mar 2000, Monteverde, Cheryl A BACH-Ft Wainwright wrote:

> I have a surgeon that has submitted a colon biopsy, and would like
> me to stain for silver. I have not found anything in the usual sources, nor
> has my pathologist (with 30 years experience) heard of such a thing.  I
> would appreciate any suggestions you might have.

 Suggestion.
  I suggest that the surgeon wanted it staining WITH silver,
  perhaps to demonstrate enteroendocrine cells or neurons and
  their processes. A British pathologist, Barbara Smith, 
  published a book on GI neuropathology, done largely with
  traditional silver methods, in the 1960s. Easier and
  (probably) better methods have been available for many
  years, and most are not silver methods.

 Reference.
  The choice of a silver technique depends on what you're
  supposed to be looking for. A quite recent whole issue of 
  J. Histotechnol. (in Vol 19, 1996) is devoted to silver
  staining methods. All the currently used techniques
  (especially for pathology) are reviewed, and there are
  detailed instructions for most of them.

 Anecdote. (Skip it if it's boring.)
  There is a rare condition of chronic silver poisoning
  called argyria. I saw a case in 1967: an old lady then,
  whose family physician had fed her silver nitrate for
  several years in the 1920s - the only thing, it seemed,
  that would relieve her indigestion. Her skin was bluish
  grey, like best quality Welsh slate, except for a large
  abdominal operation scar (from the 1940s), which was
  lily-white. This lady died in hospital (I think she 
  had mitral incompetence; nothing to do with the argyria)
  and at her necropsy the pathologist was eager to see
  which internal organs would be darkened with silver.
  The thyroid was jet black, but everything else was 
  normally coloured. It was all rather disappointing at
  the time, in a way, but has provided me with food for
  thought, on & off, ever since. It's easy to explain
  the skin and not too difficult to think of a reason
  why the internal organs were not darkly silvered.
  But why was the thyroid black?
 End of anecdote.

 Final bit (with another ref). 
  I can't believe anyone would do a colon biopsy to make
  a diagnosis of argyria. For what it's worth, silver
  deposits in tissue can be detected with great sensitivity
  but low specificity by Timm's sulphide-silver method and
  its various later variants, which have a variety of names.
  Pearse's Histochemistry (4th edn, vol 2) has a short 
  section on silver in the "Inorganic" chapter.
 The End.

 John A. Kiernan,
 Department of Anatomy & Cell Biology,
 The University of Western Ontario,
 LONDON,  Canada  N6A 5C1