[Histonet] RE: air drying special stain slides rather than

[Rene J Buesa]

Toysha:
Perhaps you have not oven dried stained slides before, and that explains some of your comments, like:
1- if the stained slides are completely dried, the "miscibility" you point out is not an issues, because there is nothing to mix with;
2- if you dehydrate → clear the stained sections that will take about 15 minutes per group of up to 25 slides, or even more depending on the protocol used in your automated stainer, but if your group of slides in their rack are placed in an oven at 60ºC for 5 minutes it will just that, 5 minutes reducing the usual TAT for each staining procedure;
3- any oven can accommodate more than 100 stained slides in their racks and the TAT is shortened by oven drying, no matter how many slides you are working with;
4- I really do not know where you can find that "extreme heat" can affect the tissue sections. All tissue sections are fixed → processed → dried (usually at the same 60ºC before staining) → stained and an additional step at 60ºC to dry before cover-slipping is just that, an additional step at 60ºC
5- The so called "Lean" technologies do not refer to staining only, they have to do with the whole work-flow and an additional drying step at 60ºC cannot affect in a negative way to the work-flow
6- after staining you will oven dry the sections.
I think you should try the method instead.
René J.


________________________________
From: "Mayer,Toysha N" <TNMayer <@t> mdanderson.org>
To: "'histonet <@t> lists.utsouthwestern.edu'" <histonet <@t> lists.utsouthwestern.edu> 
Sent: Tuesday, September 11, 2012 11:41 AM
Subject: [Histonet] RE: air drying special stain slides rather than


Ooh, great question for my students next semester.  
Your answer is the counterstain, some counterstains may require dehydration after rinsing, or some may not. Adjusting the times of the counterstain is not the issue as much as  the solvent of the counterstain.
  
Rene, while I do acknowledge that the xylene may/will cause hazards, we must think of the miscibility of the clearant and the dehydrant, as well as the amount of time involved.  The amount of time involved to blot and air dry the slides will affect the TAT for the specimen.  5 min may be ok if you have a small amount of slides, but with a larger number of slides, it will be considerably more than 5.  Also Lean methodologies would not apply in that case. With automation, the extreme heat involved with a stain dryer may affect the tissue on the slide.

There are some stains that can be blotted, cleared and coverslipped, but using the alcohol to remove excess water and counter stain is better in my opinion.


Toysha N. Mayer, MBA, HT (ASCP)
Instructor, Education Coordinator
Program in Histotechnology
School of Health Professions
MD Anderson Cancer Center
(713) 563-3481
tnmayer <@t> mdanderson.org




Message: 16
Date: Tue, 11 Sep 2012 10:32:08 -0400
From: "Diana McCaig" <dmccaig <@t> ckha.on.ca>
Subject: [Histonet] air drying special stain slides rather than
    dehydrate    and clear
To: <histonet <@t> lists.utsouthwestern.edu>
Message-ID:
    <DCFD9E6A390E294AAF3A2561CD32E5C417A90529 <@t> ckhamail1.ckha.on.ca>
Content-Type: text/plain;    charset="us-ascii"

I was hoping to get information on why special stains are dehydrated, cleared and mounted vs allowing them to be blotted dry, air dried then coverslip.



Every procedure I have ever encountered always indicates to dehydrate and clear but I have heard where some labs are blotting the slides , allowing to air dry (probably not set standard time) and dipped in xylene prior to cover slipping.  Reason given is that the counterstain gets washed out.  Wouldn't adjusting the times be a better resolution.



I understand residual water could be present and cause long term issues on storage but wanted some other opinions on this process. 



Diana



------------------------------

Message: 17
Date: Tue, 11 Sep 2012 07:52:05 -0700 (PDT)
From: Rene J Buesa <rjbuesa <@t> yahoo.com>
Subject: Re: [Histonet] air drying special stain slides rather than
    dehydrate    and clear
To: Diana McCaig <dmccaig <@t> ckha.on.ca>,
    "histonet <@t> lists.utsouthwestern.edu"
    <histonet <@t> lists.utsouthwestern.edu>
Message-ID:
    <1347375125.72189.YahooMailNeo <@t> web121405.mail.ne1.yahoo.com>
Content-Type: text/plain; charset=iso-8859-1

Diana:
The most simple answer to your question is: "Because that is the way it has been done for more than 150 years".
The second question would be: "Is it necessary?" and the short answer to this question is: NO!!!
As a matter of fact, one of the steps I have developed to totally eliminate xylene from the histology lab refers to the "clearing" of stained sections, not only "special stains" (the so called HC and IHC) but the routine as well (the H&E).
Now, the "secret" to a successful drying of the stained slides is NOT to let them air dry because that will take not only too much time, but you can never be sure if the section is completely dry and if you add the mounting medium to a not completely dried section, you will have transparency problems.
The correct way of doing that is by drying the stained sections during 5 minutes at 60?C in an oven.
Under separate cover I am sending you something I published about your question and other aspects of how to completely eliminate xylene from ALL steps in the histology laboratory.
Ren? J.


________________________________
From: Diana McCaig <dmccaig <@t> ckha.on.ca>
To: histonet <@t> lists.utsouthwestern.edu
Sent: Tuesday, September 11, 2012 10:32 AM
Subject: [Histonet] air drying special stain slides rather than dehydrate and clear

I was hoping to get information on why special stains are dehydrated, cleared and mounted vs allowing them to be blotted dry, air dried then coverslip.



Every procedure I have ever encountered always indicates to dehydrate and clear but I have heard where some labs are blotting the slides , allowing to air dry (probably not set standard time) and dipped in xylene prior to cover slipping.? Reason given is that the counterstain gets washed out.? Wouldn't adjusting the times be a better resolution.



I understand residual water could be present and cause long term issues on storage but wanted some other opinions on this process. 



Diana


_______________________________________________
Histonet mailing list
Histonet <@t> lists.utsouthwestern.edu
http://lists.utsouthwestern.edu/mailman/listinfo/histonet