Neutral red is OK.  So is janus green B. Toluidine blue will stain the granules (metachromatically), but it is likely to disrupt the mast cells. See H. Selye (1965) The Mast Cells. Washington: Butterworths, pp. 63-66. There's lots of literature on vital staining  of mast cells, dating back as far as 1895. 

John Kiernan
Anatomy, UWO
London, Canada
---
----- Original Message -----
From: Moran Elishmereni 
Date: Wednesday, October 10, 2007 16:05
Subject: [Histonet] stain living cells - what dye doesn't kill the cells?
To: histonet@lists.utsouthwestern.edu

> Dear Histonetters,
> 
> Does anyone know of a dye/stain (fluorescent or non-fluorescent) 
> that does
> not kill cells? I want to do some live-imaging of live primary 
> mast cells,
> but be able to distinguish them from other cells in a certain 
> mix. So I need
> to stain them- but not affect there viability/function.
> I know that this isnt exactly the forum for this question, but 
> I'm hoping to
> get some suggestions anyway.
> Many thanks,
> Moran
> 
> -- 
> Moran Elishmereni
> 
> Department of Pharmacology and Experimental Therapeutics
> School of Pharmacy, Faculty of Medicine
> The Hebrew University of Jerusalem
> POB 12065
> Jerusalem 91120, ISRAEL
> Tel: 972-2-675-8746
> Fax: 972-2-675-8144
> Email: moran.elish@gmail.com
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> 
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