I am a little confused re formalin pigment discussion with relation to these tissues. True
that there will be hemorrhage but to the best of my knowledge, for formalin pigment to form
there generally has to be either  an acid pH below around 5.6 to 6.0 (acid formalin hematin),
or if alkaline pH (above 8.0)  an alkaline hematin has also been reported to form.
With the use of adequately buffered formalin (phosphate buffered) there should be no "formalin
pigment " formed.
The only problem that I can see is if there is insufficient fixative either with using small
volumes or if the fixative is not changed - so that the formalin is  rapildy depleted by the
large surface area presented by the red blood cells.
Barry

Maureen Decorah wrote:

> >
> >You get massive to moderate hemorrhage in the lungs and organs with CO2 so
> >would not be surprised if you did get alot of formyl hemoglobin on
> >fixation.  Euthanasia with a euthanasia drug like Beuthanasia will give you
> >crystalline deposits in tissue.  I recommend pentobarbital IP or IV for
> >least amount of artefact.
> >
> >Dr. Annette Gendron
> >>>
> >>>A question for the group.
> >>>I'm planning an experiment in which mice will be killed and the
> >>>lungs and several other organs examined histologically.  Some of
> >>>the mice will be transgenic.  The question is, would killing the
> >>>animals with CO2 narcosis have an adverse impact on the quality
> >>>of preservation, e.g. generating formalin pigment in the spleen?
> >>>Does anyone have experience with this method?
> >>>
> >>>Thanks in advance
> >>>
> >>>Hal Hawkins
> >>>UT Medical Branch, Galveston, TX
> >>>
> >>
> >>
> >>
> >>      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~     Ma
>
> >>>
> >>>ureen Decorah, Research Animal Resources Center
> >>      385A Enzyme Institute, 1710 University Avenue
> >>      University of Wisconsin - Madison, Madison, WI 53705-4098
> >>      (608) 262-0933  Fax(608) 265-2698  E-mail: decorah@rarc.wisc.edu
> >>
> >>
> >>      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~u#184#
> >
> >
> >
> >
> >*******************************************************************************
> >Dr.Annette Gendron-Fitzpatrick                          Rm. 380 Enzyme
> >Institute
> >Research Animal Resource Center                         1710 University Ave.
> >(608) 262-1239, gendron@rarc.wisc.edu                   Madison, WI 53705-4098
> >*******************************************************************************
> >
> >
>
>         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>         Ma
> ureen Decorah, Research Animal Resources Center
>         385A Enzyme Institute, 1710 University Avenue
>         University of Wisconsin - Madison, Madison, WI 53705-4098
>         (608) 262-0933  Fax(608) 265-2698  E-mail: decorah@rarc.wisc.edu
>         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> u#196#