Re: how to dehydrate slides stained with AEC

From:John Kiernan

Dear Baowei Peng,

Some answers are inserted into your email, below. My
paragraphs begin with ** .

Your second question cannot be answered without more
information from you. See below for suggestions.
_________________________________________ wrote:
> I use AEC as chromogen reagent in IHC,
> should I dehydrate the slides after counter-stainging as in DAB was chromogen reagent? And how? I want to preserve these slides for a long time.

** The coloured oxidation product of
aminoethylcarbazole (AEC) is soluble in organic
solvents. You must use an aqueous mounting medium.
There are several commercially available aqueous media,
or you can make your own. A web search for MAKE AQUEOUS
MOUNTING MEDIA brought up scores of hits, and most of
the first 10 looked useful. Google is a wondrous thing!

> I found there was much red color (from AEC) on the slides, could those additional color be washed away?

** The red colour should be only at sites of the
antigen. If it is elsewhere you are doing something
wrong. Negative control slides (omitting individual
stages of the procedure) are extremely important in
immunohistochemistry. They will show you which part of
the method is causing the false-positive (unwanted)
colour. Positive control sections (known to contain the
antigen at recognizable sites) are also necessary. 

** First: get the method to work properly with a known
positive tissue.
** Next: try the method on the tissue you are

> Baowei Peng
> Shanghai JiaoTong University,
> Shanghai,200030

John A. Kiernan
Department of Anatomy and Cell Biology
The University of Western Ontario
London,   Canada   N6A 5C1

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