Re: [Histonet] Mineral deposits and von Kossa & alizarin S

From:Philip Oshel

Do you have access to a SEM with an energy-dispersive x-ray 
spectrometer (EDS)? If yes, this could give a positive ID of the 
element(s) and would be relatively quick. If you only care about the 
mineral and not morphology, at least initially, you can air-dry 
unfixed tissue, mount, and carbon-coat to do the spectra.


>A colleague has asked me to post this for him:
>We recently found what appears to be mineral within
>mouse heart tissue.  This mineral stains with von
>Kossa, but was negative with Alizarin Red S, with the
>exception of a single mineral deposit in one animal.
>The hearts were fixed in neutral buffered formalin
>(NBF).  Is it possible that the calcium leached out in
>the NBF and that is the reason for the negative result
>with Alizarin Red?  Some of the older literature
>suggests using alcohol fixatives, but more recent
>literature recommends using NBF.   If the calcium
>leached out would you still expect to see non-staining
>mineral deposits, or should the entire deposit be
>dissolved away and absent from the tissue section?
>Also, some people have suggested that to increase the
>confidence (of the von Kossa stain) that the blackened
>material is calcium a duplicate tissue section can be
>decalcified with citrate buffer (pH 4.5), 10 % formic
>acid, or 0.5% aqueous hydrochloric acid.  Has anybody
>had any luck with one of these procedures to help
>characterize mineral?  Is there a reference available
>on this modified method?
>Mike Thibodeau, DVM, PhD, DACVP
>Senior Scientist, Pathologist
>Department of Toxicology and Safety Assessment
>Boehringer Ingelheim Pharmaceuticals Inc.
>900 Ridgebury Rd, P.O. Box 368
>Ridgefield CT, 06877
>Phone: (203) 791-6124
>Mobile: (203) 546-0260
>Roger Moretz, Ph.D.
>Senior Scientist, Electron Microscopist
>Dept of Toxicology & Safety Assessment
>Boehringer Ingelheim Pharmaceuticals, Inc.
>900 Ridgebury Rd
>Ridgefield, CT 06877
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Philip Oshel
Microscopy Facility Supervisor
Biology Department
Central Michigan University
024C Brooks Hall
Mt. Pleasant, MI 48859
voice: (989) 774-3576
dept. fax: (989) 774-3462

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