Bourassa, Patricia wrote:
>
> Hi, There!
>
> Has anyone had any experience using Alizarin Red to stain for Calcium
> deposits?  I was wondering if there were any fixation and/or embedding
> restraints.

As for fixation: Do NOT use:

- any formalin that has a calcium salt as a buffer.
This could give a false positivity.

- any fixative containing acetic acid or picric acid.
These acids will decrease the amount of calcium in the
tissue, particularly the areas of microcalcification.
This could result in a false negativity.

As for processing restraints, hopefully it goes without saying . . .
DON'T decalcify the tissue! Otherwise than that, process and
embed as usual for that type of tissue.


Also, does anyone have any good protocols for a specific
> staining method for calcium?


I see that others have already responded to this, so I'll
skip over the actual procedure.

Just a few notes on Alizarin red:

- Alizarin red is more sensitive for small amounts of calcium
in the tissue than the von Kossa.

- Another advantage of the alizarin red is that it is cheaper
(von Kossa uses silver, plus the cost of the silver disposal)
and is faster (30 seconds to 5 minutes at room temp).

- Neither Alizarin red nor von Kossa are specific for calcium
Other elements will also be stained. However, these other
elements are usually not found in high enough concentration
in the body. By adjusting the pH of the Alizarin red, it does
become a little more specific for calcium, rather than some
of the other elements.


>
> Thanks!!
>
> -Patti Bourassa
>  Pfizer, Groton

--
Peggy A. Wenk, HTL (ASCP)
Anatomic Pathology
Wm. Beaumont Hospital
3601 W. 13 Mile Rd.
Royal Oak, MI 48073-6769