Re: Calcification of Mouse Tissues

From:Karen Pawlowski

Ok Gayle,

I have never done von Kossa, but it makes sense that if you are trying
to detect calcium, you wouldn't want to remove it first.
I know that typically kidneys etc. don't need decalcification either, 
but that was actually why I mentioned it.  Often techniques are carried
through like "business as usual" without much thought of why things 
are done and if, for some odd reason, these tissues had been 
decalcified, the person embedding it may have overlooked that fact or
someone else did the initial steps and the technician didn't know that
they included a decal. step.  This would explain the calcium in the
nucleus.  I couldn't think of any other reason for the stain to 
show up there, unless there was some calcium contaminant in one of
the solutions for staining that precipitated out during the process. 
Just the other day I almost forgot to decalcify some tissue, because 
we typically trim the bone off before sectioning, so the decal step
isn't needed.  This time, however, I am sectioning at a different 
angle and I won't be able to trim the bone, it will be
running throughout the tissue. I was in the middle of doing three
things at once and I luckily remembered I needed the decal. about
5 minutes before I went from a rinse into alcohol.

Karen Pawlowski

Gayle Callis wrote:
> I think in order so see a positive von Kossa, decalcification cannot be
> done at any time.
> At 11:20 PM 9/23/02 -0500, you wrote:
> >Hi Keith,
> >
> >Just a thought, was the tissue decalcified before embedding?  If so,
> >then going straight from a decalcifying agent to alcohol dehydration
> >can cause precipitation of the calcium that was dissolved in the
> >decalcifying agent. That calcium could end up anywhere.
> >
> >Karen Pawlowski
> >Research Scientist
> >UT Dallas, Dallas, Texas
> >
> >Keith Rogers wrote:
> >>
> >> Dear Histonet,
> >>
> >> I hope to catch you all before you head west to California.
> >>
> >> Reviewing slides with an unusual pattern of calcium deposition,
> >> confirmed with Von Kossa, one of our pathologists asked if this could
> >> be a histology induced artefact. The calcium is deposited in all of
> >> the normal places, gut, kidney etc, and also in heart. Although
> >> calcium deposition in the heart is not uncommon, there seems to be no
> >> good explanation for it. i.e. there is no underlying condition which
> >> would explain the calcium deposits. What is more of a concern is the
> >> deposition of calcium inside the nuclei of some cells.
> >>
> >> I would be grateful to hear from anyone who has experience with this
> >> or any thoughts on the subject.
> >>
> >> Keith Rogers
> >> NCI Cancer Research Center
> >> Frederick
> >> MD
> >> Keith
> >>
> >
> >
> >
> >
> Gayle Callis
> Research Histopathology Supervisor
> Veterinary Molecular Biology - Marsh Lab
> Montana State University - Bozeman
> 19th and Lincoln St
> Bozeman MT 59717-3610
> 406 994-6367 (lab with voice mail)
> 406 994-4303 (FAX)
> email:

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