[Histonet] Poor Eosin staining after prolonged fixation

[Geoff McAuliffe]

Hi Janet:

    I recall hearing of this problem and I looked in my old copy of 
Humason's text to find the solution. Naturally, the solution was not 
there! However, I suggest a short oxidation with 0.25% potassium 
permanganate followed by bleaching with 0.5% oxalic acid for a minute or 
two until the sections are colorless. Wash thoroughly. This should 
improve the staining, but be careful it may improve it too much!

Geoff

Keeping, Janet wrote:
> Has anyone experienced poor eosin counterstaining using tissues which
> have had very prolonged fixation in neutral buffered formalin? The
> tissues I have for students have been fixed for a very long time. (not
> generally a problem in the clinical site). Although the pH of the stain
> is between 4.6-5.0, the slides are well washed following bluing, time in
> 70% alcohol for differentiation is minimal  and eosin staining times
> have been increased the counterstaining is still poor. I am guessing
> that the tissue groups that bind with eosin are not accessible due to
> continued cross linking. Any ideas or suggestions? 
>
>  
>
> Janet Keeping A.R.T., B. Voc. Ed
>
> Instructor
>
> Medical Laboratory Sciences
>
>  
>
> 1 Prince Philip drive
>
> P.O. Box 1693, St. John's 
>
> NL, Canada A1C 5P7
>
> 709 758 7657 tel
>
> 709 758 7635 fax
>
> E-mail; janet.keeping <@t> cna.nl.ca
>
>  
>
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Geoff McAuliffe, Ph.D.
Neuroscience and Cell Biology
Robert Wood Johnson Medical School
675 Hoes Lane, Piscataway, NJ 08854
voice: (732)-235-4583 
mcauliff <@t> umdnj.edu
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