[Histonet] re: concentration of formaldehyde in soultion: ASTM D2194 - 02(2007) Standard Test Method for Concentration of Formaldehyde Solution

[Susan Bachus]

I believe that the "swiss cheese" holes are due to ice crystal format=
ion=20
during freezing, at least that's the rationale we were always taught =
for=20
using additional fixation in sucrose-formalin after the initial fixat=
ion in=20
formalin, i.e. the sucrose would prevent ice crystal formation.   Sus=
an
----- Original Message -----=20
=46rom: "tf" <tifei <@t> foxmail.com>
To: "Walters, Katherine S" <katherine-walters <@t> uiowa.edu>; "Tony Henwo=
od"=20
<AnthonyH <@t> chw.edu.au>; "Pat Flannery" <pjfnefro <@t> duke.edu>;=20
"histonet <@t> lists.utsouthwestern.ed" <histonet <@t> lists.utsouthwestern.edu=
>
Sent: Friday, December 12, 2008 10:12 AM
Subject: [Histonet] re: concentration of formaldehyde in soultion: AS=
TM=20
D2194 - 02(2007) Standard Test Method for Concentration of Formaldehy=
de=20
Solution


> http://www.astm.org/Standards/D2194.htm
>
> ASTM D2194 - 02(2007)
>
>
> ASTM D2194 - 02(2007) Standard Test Method for Concentration of=
=20
> Formaldehyde Solutions
>
>
> 2008-12-12
>
>
>
> tf
>
>
>
> =B7=A2=BC=FE=C8=CB=A3=BA Walters, Katherine S
> =B7=A2=CB=CD=CA=B1=BC=E4=A3=BA 2008-12-12  21:49:26
> =CA=D5=BC=FE=C8=CB=A3=BA tifei <@t> foxmail.com; Tony Henwood; Pat Flann=
ery;=20
> histonet <@t> lists.utsouthwestern.ed
> =B3=AD=CB=CD=A3=BA
> =D6=F7=CC=E2=A3=BA RE: [Histonet] (reply) silly questions.---PFA
>
> This may be another silly question, but how does one test the=20
> concentration of formaldehyde in solution?
> Thanks,
> Kathy
> Notice: This UI Health Care e-mail (including attachments) is cover=
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> then delete it.  Thank you.
> -----Original Message-----
> From: histonet-bounces <@t> lists.utsouthwestern.edu=20
> [mailto:histonet-bounces <@t> lists.utsouthwestern.edu] On Behalf Of tf
> Sent: Friday, December 12, 2008 2:35 AM
> To: Tony Henwood; Pat Flannery; histonet <@t> lists.utsouthwestern.ed
> Subject: [Histonet] (reply) silly questions.---PFA
> "I looked at the sections and the cell shrinkage (and prominent spa=
ces
> between cells and connective tissue) indicated that most of the
> "fixation" seemed to have occured in the processing ethanols. I ask=
ed
> him for some of the fixative he used, tested the formaldehyde
> concentration and found it to be less than 0.5%!!"
> Tony: Do you think this is because of inproper preparation of PFA i=
n his=20
> lab, or the common problem in all researchers using PFA?
>         I do think most biomedical labs currently are using PFA to =
prepare=20
> the fixatives!
>
> So, anyone has the idea on a correction preparation procedure of 4%=
 PFA?
> I noticed some of you dissolve PFA powder in NaOH-conditioned alkal=
ine=20
> water, then add concentrated PB solution.
> We here dissolve PFA in concentrated PB solution directly (heat & s=
tir for=20
> 2-3 hours), then adjust pH to 7.4.
> We dont have big problem in tissue quaility....except when one want=
 to cut=20
> the brain in a cryostat rather sliding microtome.
> Many times the brain sections from the cryostat have "cheese" like=
=20
> holes/cavities, which almost never appear on sliding microtome-prep=
ared=20
> sections.
> 2008-12-12
> tf
> =B7=A2=BC=FE=C8=CB=A3=BA Tony Henwood
> =B7=A2=CB=CD=CA=B1=BC=E4=A3=BA 2008-12-12  06:18:47
> =CA=D5=BC=FE=C8=CB=A3=BA Pat Flannery; histonet <@t> lists.utsouthwester=
n.edu
> =B3=AD=CB=CD=A3=BA
> =D6=F7=CC=E2=A3=BA RE: [Histonet] Silly Question?
>
> Pat,
> I agree with you.
> In a routine diagnostic histopathology laboratory, it makes little
> difference what you use. Around the world for over 100 years most l=
abs
> use 10% neutral buffered formalin made from concentrated 38%(or the=
re
> abouts) formalin (or formaldehyde).
> Researchers, though, are a different kettle of fish. They will tend=
 to
> hang on to misinformed, "mystical" methods believing they are being
> scientific. Funny, you would think that they, as a group, would be =
the
> ones pushing the boundaries and critically assessing each step of t=
heir
> research, ensuring that they understand what and why they are doing=
 it.
> (Disclaimer - not all researchers are like this, thank heavens!!)
> Using a formaldehyde solution made from polyformaldehyde can cause
> problems. One researcher used it and wondered why their morphology =
was
> sub-optimal and their p53 immunohistochemistry was negative. He ass=
ured
> me that he had fixed small samples of tissue for 6 hours in 4%
> formaldehyde and then processed them using ethanol, xylene and wax.
> I looked at the sections and the cell shrinkage (and prominent spac=
es
> between cells and connective tissue) indicated that most of the
> "fixation" seemed to have occured in the processing ethanols. I ask=
ed
> him for some of the fixative he used, tested the formaldehyde
> concentration and found it to be less than 0.5%!!
> This also explains the loss of p53 staining. I gave him some of our
> routine 10% phosphate buffered fomalin, asked him to fix overnight,=
 and
> try agin. Low and behold problem solved.
> How's that for a Friday Flamming!!!
> 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 Pat
> Flannery
> Sent: Friday, 12 December 2008 3:59 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) rathe=
r
> than buffered formalin or just diluted formaldehyde itself?
> It seems that around here, some folks prefer paraformaldehyde (eith=
er
> 2% or 4%) and others use formalin, while some others stick to dilut=
ed
> 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 us=
e
> 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 la=
b)
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