[Histonet] Re: Histonet Digest, Vol 26, Issue 19

Thu Jan 26 16:47:09 CST 2006

re:paraformaldehyde

In our lab we use the para powder and yes it is very
airborne.  But....we carefully weigh out the powder
with the hood sash completly up or using a mask
outside of the hood.

The we carefully place it in a ziplock bag.  Whe we
need it we just cut the end and slowly poor it into
our water.  This eliminates alot of powder in the air
...just a thought...

Gloria Limetti
University of Pgh
Vestibular Research

--- histonet-request <@t> lists.utsouthwestern.edu wrote:

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> Today's Topics:
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>    1. Re: Dry Stains Shelf Life (John A. Kiernan)
>    2. Re: paraformaldehyde crystals v Prills (John
> A. Kiernan)
> 
> 
>
----------------------------------------------------------------------
> 
> Message: 1
> Date: Tue, 17 Jan 2006 12:41:28 -0500
> From: "John A. Kiernan" <jkiernan <@t> uwo.ca>
> Subject: Re: [Histonet] Dry Stains Shelf Life
> To: Sharon E Willman <sharon.willman <@t> bms.com>
> Cc: histonet <@t> lists.utsouthwestern.edu
> Message-ID: <43CD2C48.F22D41E4 <@t> uwo.ca>
> Content-Type: text/plain; charset=us-ascii
> 
> See the following publications:
> 
> Emmel VM & Stotz EH 1986. Certified biological
> stains: a stability study. Stain Technol.
> 61:385-387.
> Titford M 2001. Comparison of historic Grubler
> dyes with modern counterparts. Biotech. Histochem.
> 76:23-30.
> Titford, M. 2002. Save that dye! Microscopy Today
> 18-5:31-34.
> 
> The general conclusion is that nearly all dye
> powders still work after 100 years (Titford).
> Quantitative assays show very little deterioration
> over 20 or so years (Emmel & Stotz). Matt Frank
> may have more recent information from the
> Biological Stain Commission's lab.
> 
> Alcian blue 8G can deteriorate in the solid state,
> changing to an insoluble pigment. This is not a
> problem with the pyridine variant of alcian blue
> (Churukian et al 2000, Biotech. Histochem. 75:
> 147-150). Acidic solutions of alcian blue 8G are
> stable for some years on my shelves. Churukian's
> lab manual gives a recommended shelf life of 6
> months. An alcian blue solution with a precipitate
> should be discarded and replaced, not filtered and
> used.
> -- 
> -------------------------------
> John A. Kiernan
> Department of Anatomy and Cell Biology
> The University of Western Ontario
> London,   Canada   N6A 5C1
>    kiernan[AT]uwo.ca
>    http://publish.uwo.ca/~jkiernan/
>    http://instruct.uwo.ca/anatomy/530/index.htm
> _______________________________
> Sharon E Willman wrote:
> > 
> > Hi,
> > What is the expiration time for dry stains and how
> often should you
> > replenish?  Many times they do not have expiration
> dates on them when
> > they come in from the manufacturer.
> > I would appreciate any information on this matter.
> > Thanks,
> > Sharon Willman
> >
> 
> 
> 
> ------------------------------
> 
> Message: 2
> Date: Tue, 17 Jan 2006 12:55:20 -0500
> From: "John A. Kiernan" <jkiernan <@t> uwo.ca>
> Subject: Re: [Histonet] paraformaldehyde crystals v
> Prills
> To: Carl Hobbs <carl.hobbs <@t> kcl.ac.uk>
> Cc: histonet <@t> lists.utsouthwestern.edu
> Message-ID: <43CD2F88.7CA05654 <@t> uwo.ca>
> Content-Type: text/plain; charset=us-ascii
> 
> Carl Hobbs wrote:
> > 
> > Many of our Groups use paraformaldehyde crystals (
> Sigma P6148) to make up
> > their solution of formalin. Works very well; 4g +
> 1tab PBS + 6microlitre
> > 10MNaOH.....stir overnight. Dissolved
> completely:pH7.2
> > I am trying to get away from using this
> paraformaldehyde: it is very light
> > and prone to spread around the fume hood when it's
> weighed out.
> >     So, I bought PRILLS from Sigma:Problem is,
> they just do not dissolve
> > completely, unless I preboil the water.( heating
> to 60C is not hot enough to
> > dissolve the Prills.
> >  I have tried all combinations of the formulation
> above( eg: no NaOH,
> > dissolving PBS tablet before adding
> paraformaldehyde).
> > I want the procedure with the least risk; boiling
> may be a higher risk than
> > the spread of powder.
> > NB: I cannot turn down/off the fume hoods, for the
> weighing of the
> > crystals( which behave more like a very fine
> powder), hence my desire to use
> > the heavier Prills.
> > 
> > Be grateful for any insights.
> > Carl
> 
> You can avoid the fine powder and insolubility
> problems by making your fixative from formalin
> rather than paraformaldehyde. 
> 
> A good mixture, shown to be OK even for electron
> microscopy, is that of Carson FL, Martin JH & Lynn
> JA 1973, Am. J. Clin. Path. 59:365-373. Its
> composition is:
> Formalin 100 ml
> Water 900 ml
> Monobasic sodium phosphate, monohydrate 18.6 g
> Sodium hydroxide 4.2 g
> The pH is 7.2-7.4 and the solution can be kept for
> several months.
> 
> As always, don't rely on the accuracy of this or
> any other email! Consult the original paper before
> making and using the fixative.
> -- 
> -------------------------------
> John A. Kiernan
> Department of Anatomy and Cell Biology
> The University of Western Ontario
> London,   Canada   N6A 5C1
>    kiernan[AT]uwo.ca
>    http://publish.uwo.ca/~jkiernan/
>    http://instruct.uwo.ca/anatomy/530/index.htm
> _______________________________
> 
> 
> 
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> End of Histonet Digest, Vol 26, Issue 19
> ****************************************
> 

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