Re: Fwd: microwave slide drying

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From:"Adrienne Vair" <>,
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>We have been sucessfully drying our slides for H&E in a microwave for
>many years.  When you first get your microwave it is trial and error to
>find the correct time and power selection.

What is the wattage of the microwave oven that you are using?

Do this by making slides of
>representative tissue, ie: colon, uterus, gastric biopsy, poc- dry, stain
>and examine microscopically.   1. A turntable is a must. 2. Be sure all
>excess water is removed from the slides. (tap the rack a few times on a
>thick cushion of paper towels)  3. Be sure to use a microwaveable rack.
>4. Transfer slides to staining rack immediately and stain.  If your
>stainer has a heating chamber program the station for 5 min @ 58-60 deg C
>before staining.  The time we use is 3 minutes @ power level 4.  This is
>good for 1 to 20 slides. If drying 1 and 1/2 racks stack the racks on top
>of each other and heat for 3 1/2 min @ power level 4.  The only time we
>have had artifact is when the tech does not take the time to be sure all
>excess moisture is removed before placing into the microwave.

What type of artifact would one expect if there is excessive moisture on the 
slides before drying them in the microwave oven? What type of artifact would 
one expect if the slides were microwaved too long? Does it affect tertiary 
structure of the proteins?

Our pathologists have some concerns with muddy staining (H&E) specifically 
the nuclear staining, and I have been unable to resolve it.  Could this be a 
moisture problem that others have mentioned on this mailing list? I have 
considered the following various aspects and experimented at great length 
with:  fixation times in NBF, pH of tap water before staining in Hematoxylin 
(Hx)(we have a Hacker Linear Automated stainer), various types of 
Hematoxylin's (Gill's, Harris's), washing times and velocity of the tap 
water during washing after staining in Hx as well as various bluing agents.  
I have considered changing the fixative from Neutral Buffered Formalin to 
Zinc Buffered Formalin as I have heard that it is superior but the 
pathologists were concerned that it might clog internal parts of the VIP 
Tissue Processor (something they had experienced in past). I have also 
experimented with slide drying times and temperatures in a microwave oven 
and oven.  In the end I chose to dry the slides for 1 hour at 60 degree 
Celsius in the oven (something I had been taught in University)  Are there 
any procedure suggestions for drying slides in an oven ie. minimum time 
required in the oven before staining, what the slide should look like 
macroscopically if dried too long or not long enough, should the slides be 
cooled before staining, etc.

Any suggestions would be appreciated.

>Microwaving saves so much time.  We also use microwave technique for many
>of our special stain.
>Good luck
>Pat Q
>Olean, NY

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