[Histonet] Silly Question? - Need help quickly!

Thu Dec 11 16:29:40 CST 2008

Good point

Regards

Tony Henwood JP, MSc, BAppSc, GradDipSysAnalys, CT(ASC)
Laboratory Manager & Senior Scientist
Tel: 612 9845 3306
Fax: 612 9845 3318
the children's hospital at westmead 
Cnr Hawkesbury Road and Hainsworth Street, Westmead 
Locked Bag 4001, Westmead NSW 2145, AUSTRALIA 

-----Original Message-----
From: histonet-bounces <@t> lists.utsouthwestern.edu [mailto:histonet-bounces <@t> lists.utsouthwestern.edu] On Behalf Of Merced Leiker
Sent: Friday, 12 December 2008 5:19 AM
To: rjbuesa <@t> yahoo.com; Pat Flannery; histonet <@t> lists.utsouthwestern.edu; Weems, Joyce
Subject: RE: [Histonet] Silly Question? - Need help quickly!

So...is a polymer of paraformaldehyde considered "depolymerized" if it 
remains somewhere between 1-50 molecules long once it's been  dissolved in 
solution, however it's dissolved? (the dissolving being a separate topic of 
debate on Histonet).  Does it matter for tissue fixation purposes if there 
are formaldehyde chain lengths of 50 molecules present in solution - not 
long enough to precipitate out, but perhaps long enough to affect its 
penetration and fixing of tissues?  Any ideas?

Merced

--On Thursday, December 11, 2008 9:58 AM -0800 Rene J Buesa 
<rjbuesa <@t> yahoo.com> wrote:

> Joyce:
> Methanal, which is the chemical name of formaldehyde, polymerizes. If 
> it forms a polymer of at least 50 molecules or more, it gets solid = 
> para-formaldehyde. Formalin (a trade name as formol is also another 
> trade name)is the 37-50% aqueous solution of formaldehyde (with some 
> additiveses to prevent polymerization). You can prepare BNF using the 
> formalin solution or dissolving the amount of solid 
> para-formaldehydede to get to the concentrationon you desire. The 
> chemical in both solutions is the same = methanal or formaldehyde.René 
> J.
>
> --- On Thu, 12/11/08, Weems, Joyce <JWeems <@t> sjha.org> wrote:
>
>
> From: Weems, Joyce <JWeems <@t> sjha.org>
> Subject: RE: [Histonet] Silly Question? - Need help quickly!
> To: "Pat Flannery" <pjfnefro <@t> duke.edu>, 
> histonet <@t> lists.utsouthwestern.edu
> Date: Thursday, December 11, 2008, 12:12 PM
>
> I was just going to post a question regarding paraformaldhyde myself! 
> Just last week I believe I remember someone saying that 
> paraformaldehyde and formalin are the same and they had put the same 
> solution in two different containers for one of their researchers 
> because they were so insistent to have two different solutions. Are 
> they the same?
>
> Well, today I have a request to put tissue for a researcher in 
> formalin and paraformaldehyde. So.... Without percentage required, do 
> I use 10% NBF? Do I call somewhere and get paraformaldehyde and make 
> 4% paraformaldehyde?
>
> I have asked the surgeon twice for the number for the lab so I can 
> find out - don't have it yet. I have two fresh adrenals in the fridge. 
> Help!!
>
>
> Thanks in advance...
> Joyce
>
> Joyce Weems
> Pathology Manager
> Saint Joseph's Hospital
> 5665 Peachtree Dunwoody Rd NE
> Atlanta, GA 30342
> 678-843-7376 - Phone
> 678-843-7831 - Fax
>
>
>
> -----Original Message-----
> From: histonet-bounces <@t> lists.utsouthwestern.edu
> [mailto:histonet-bounces <@t> lists.utsouthwestern.edu] On Behalf Of Pat 
> Flannery
> Sent: Thursday, December 11, 2008 11:59 AM
> To: histonet <@t> lists.utsouthwestern.edu
> Subject: [Histonet] Silly Question?
>
> Please humor me on this if it's obvious (to everyone but me):  why do 
> we use paraformaldehyde (which is so inconvenient to make up) rather 
> than buffered formalin or just diluted formaldehyde itself?
>
> It seems that around here, some folks prefer paraformaldehyde (either 
> 2% or 4%) and others use formalin, while some others stick to diluted 
> formaldehyde (I see all 4 on labels for specimens submitted for 
> histology).  Is it mostly a matter of personal preference or where you 
> were trained (i.e. force of habit) or is there a valid reason to use 
> each solution (basically the same chemical once in solution, merely 
> buffered or not)?  The only answer I've gotten when I've asked is, 
> "That's what we always use."
>
> Thanks.
>
> -Pat Flannery (not a "real" histologist - I just play one in the lab)
>
>
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Merced M Leiker
Research Technician II
354 BRB (pkgs) / 140 Farber Hall (letters)
School of Medicine and Biomedical Sciences
State University of New York at Buffalo
3435 Main St, Buffalo, NY 14214
Ph: (716) 829-6033
Fx: (716) 829-2725

"Without my flaws I'm really very boring."
- random internet blog commentator

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