[Histonet] glyoxal fixation

[Ada Feldman]

As the developers of the Prefer fixative we would like to address  
some of the issues.

Interchangeability of glyoxal products: The manufacturer of each  
fixative should be able to provide the information necessary to work  
with their fixative in conjunction with any other fixative that a lab  
may be using. Just as an example, Hollandes is not compatible with  
NBF and requires special attention. As for Prefer we can say it is  
compatible with the majority of other fixatives, glyoxal or not.

Limited time in the fixative: There is a slight reduction in staining  
intensity after several weeks, but increasing staining time corrects  
this. So tissues are not rendered unstainable.

Transition period: This is true any time you are switching fixatives  
or processing methods.

Eosinophila: Your statements here are true.

Lysis of erythrocytes: True again. It is often seen as an advantage  
because diagnostics cells are easier to see.

Breast cancer: It would seem that the improved nuclear morphology  
would make marked nuclear variation easier to determine.

Prostate biopsies: Hope you can get a response from any of the  
glyoxal users with prostate biopsies. We would be interested  in this  
answer also.


Ada T. Feldman, MS, HT/HTL(ASCP)
ANATECH LTD.
1020 Harts Lake Road
Battle Creek, MI 49015

Phone: 800.262.8324
Fax: 269.964.8084
email: adafeldman <@t> anatechltdusa.com
website: www.anatechltdusa.com


On Jul 14, 2006, at 4:13 PM, RSRICHMOND <@t> aol.com wrote:

> The people at Anatech, makers of Prefer fixative, have published a  
> review of
> glyoxal fixation that every pathologist and histotechnologist ought  
> to read.
> This working surgical pathologist would like to add - and solicit -  
> some
> comments on Histonet.
>
> "Glyoxal Fixation and Its Relationship to Immunohistochemistry".  
> Richard W.
> Dapson, Ada T. Feldman, and Dee Wolfe. Anatech Limited, Battle  
> Creek MI. The
> Journal of Histotechnology June 2006;29:65-76.
>
> I don't want to change, but I think we all need to be prepared for  
> the day
> when a manager walks into our laboratory, or a letter from a  
> regulatory agency
> arrives in the mail, telling us that we have to get rid of  
> formaldehyde right
> now. Probably glyoxal is the only acceptable substitute, and we all  
> need to
> have a look at it. I have a number of questions.
>
> Interchangeability of glyoxal products: Prefer is described as a  
> buffered
> solution of glyoxal with a pH of about 4. The formula is a trade  
> secret.
> Competing glyoxal products probably also have trade-secret  
> formulas. So can a lab
> change brands of buffered glyoxal without problems, or does it have  
> to stay with a
> particular brand with its trade-secret buffering? - We've seen a  
> similar
> problem with distilling aliphatic xylene substitutes: every one of  
> them requires a
> separate distillation routine, at least on a spinning-band still. -  
> I'll
> leave it to John Kiernan to comment on the appropriateness of trade- 
> secret
> reagents in histopathology.
>
> Limited time in the fixative: Tissue can be left in neutral  
> buffered formalin
> for quite a long time and still be stainable, but tissue stored in  
> glyoxal
> becomes unstainable after about two weeks. Can glyoxal fixed tissue be
> transferred to 70% ethanol for more prolonged storage? - A very  
> occasional surgical
> specimen requires additional blocks after a week - a bigger problem  
> will be the
> pathologist who doesn't trim his autopsies promptly.
>
> Transition period: A laboratory changing to glyoxal would have to  
> keep IHC
> procedures for both fixatives working for some time. There would  
> have to be some
> way to identify whether a block was fixed in formaldehyde or glyoxal.
>
> Eosinophilia: One ought to be able to distinguish eosinophils from
> neutrophils in tissue sections by nuclear morphology, without  
> having to see granules.
> But quantitation of eosinophils - needed in an increasing number of  
> GI biopsy
> situations - could be a problem. We might need an IHC for  
> eosinophils in some of
> these settings.
>
> Lysis of erythrocytes: Not much of a problem, since we're used to  
> it with
> acid fixatives anyway.
>
> Breast cancer: Elimination of nuclear bubble artifact in breast biopsy
> specimens may raise the apparent nuclear grade of tumors, and thus  
> increase
> Nottingham (Elston-Ellis) scores.
>
> Prostate biopsies: I'd want to see some prostate biopsies - is  
> somebody from
> OURLab in Nashville still on this list? - with formaldehyde  
> fixation, nucleoli
> are a strong criterion of malignancy, and if glyoxal fixation  
> demonstrates
> nucleoli in benign ductal epithelium, this criterion is lost.
>
> Bob Richmond
> Knoxville TN and Gastonia NC
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Ada T. Feldman, MS, HT/HTL(ASCP)
ANATECH LTD.
1020 Harts Lake Road
Battle Creek, MI 49015

Phone: 800.262.8324
Fax: 269.964.8084
email: adafeldman <@t> anatechltdusa.com
website: www.anatechltdusa.com