Re: cold or warm pfa (also: what is PFA ?)

From:Gilmor Keshet <>

PFA is paraformadehyde, the polymer of formalin. (4% paraformaldehyde in a 
solution makes 10% formalin).
When the animal is perfused with cold PB or PFA, there will be activated 
macrophages sticking to the vessels. If you wish to minimize the amount of 
circulating cell in the specimen, you can perfuse with warm buffer. If it 
doesn't matter, it is better to use ice cold PFA, to prevent activity of 
proteases and RNAses.
Gilmor Keshet.

At 10:56 PM 7/11/2001 , you wrote:
>On Wed, 11 Jul 2001, Sunil Thomas K wrote:
> > for transcardial perfusion what is generally used. cold
> > or warm ( body temprature) PFA. I have seen reports
> > which specifically state they used cold PFA (4oC).
>Think!  What might be better than room temp (20C)
>and WHY ???  (I assume that the fixative is formaldehyde.)
>Cold will constrict the blood vessels.
>Warm will accelerate autolysis.
>What is "PFA" ?
>John A. Kiernan
>Department of Anatomy & Cell Biology
>The University of Western Ontario
>London,  Canada   N6A 5C1
>    kiernan@uwo.c

<< Previous Message | Next Message >>