Re: GEWF colon CA lymph node fixative

From:Lynn Gardner <>

Hey Bob,

Just some information I though you might be interested in! This GEWF has
been around for a while (may not be exact but is real close) we buy this
commercially which is something called Pen-Fix, which is basically a
modified alcoholic formalin. Alcoholic formalin has been around since Dezna
Sheehan's time, however, not many people used straight alcoholic formalin
due to it's drying effect on tissues like spleen, liver and uterus. The
addition of the acetic acid seemed to make the difference.  

I have been using Pen-Fix for close to 20 years and here is what we do. You
receive the speicmen in 10% NBF then trasfer to Pen-Fix when received in
the lab (with the exception of small biopsies). Allow to sit overnight and
the nodes just pop out at you, no more hunting! It also helps to sort of
fix fatty tissues ( it doesn't truely fix the fat but removed the water
making it more firm and easier to cut). This product when used with less
time in the alcohol and xylene on the processor gives you beautiful
morphology, increases the intensity of routine and special staining and is
great for immunohistochemistry and In Situ. 

No I am not a sales rep for this product but it does work. I use this a lot
in my work and so far have been extremely happy with it!

Lynn Gardner, HT(ASCP)
Senior Histological Technician
The University of Iowa
Anatomy and Cell Biology
51 Newton Road
1-100 BSB
Iowa City, IA 52242
Phone: 319-353-5490
Fax: 319-335-7770

At 06:48 PM 5/1/01 -0400, you wrote:
>A lot of us on the Pathology (PATHO-L) and Histology (HistoNet) listservers 
>use special fixatives to facilitate retrieval of lymph nodes from colorectal 
>cancer specimens. A group from the University of Western Ontario (at London) 
>has an interesting method I'd like to try out. What's different about this 
>technique from others I've seen is the use of the special fixative as a 
>postfixative after overnight formalin fixation, a real convenience if you 
>receive a lot of half-fixed specimens such as most of us do.
>"GEWF solution: an inexpensive, simple, and effective aid for the retrieval 
>of lymph nodes from colorectal cancer specimens." 
>Ken J. Newell, Barry W. Sawka, Brian F. Rudrick, David K. Driman. 
>Arch Pathol Lab Med, May 2001;125:642-645.
>GEWF solution consists of:
>   100 parts absolute ethanol [or reagent alcohol, I'm sure]
>     34 parts water
>     16 parts strong (37%) formalin
>     10 parts glacial acetic acid
>mixed in the order listed [why does that matter?]
>Open, pin out, and fix the specimen overnight in neutral buffered formalin
>detach the pericolic fat 
>postfix it overnight in GEWF solution
>dissect out lymph nodes
>The technique increased the average number of nodes recovered from 7 to 10, 
>doubled the number of positive nodes found, and decreased the average size of 
>positive nodes from 7 m to 5 mm. The authors found no interference with 
>immunohistochemical stains.
>Bob Richmond
>Samurai Pathologist
>Knoxville TN

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