[Histonet] RE: Skin Frozen Sections

[Shanu Mehta]

Thank you Gayle Callis, Alexandra Meinl & Lee Dickey for the suggestions.
 
I will try to incorporate as many suggestions as possible.
 
However,
 
1) Regarding folding the skin into a V shape: I cut a 5mm punch biopsy into half (one half for frozen & the other for paraffin embedding). So this leaves me with a very small piece of semi circle to work with. I will try though to fold it the next time I do some embedding!
2) I do not shave the skin - I rather cut off as much hair as possible. So in the end, I have tiny hair with the biopsy.
 
Most of the other points made are generally followed but I will be extra careful to follow them all!
 
Thanks a lot. I really appreciate all the comments.
 
Shanu
 

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________________________________

From: Lee E. Dickey [mailto:ledickey <@t> Coretech-holdings.com] 
Sent: Tuesday, January 20, 2009 2:45 PM
To: Shanu Mehta
Subject: Skin Frozen Sections



Shanu

 

I agree with all of the suggestions from Gayle Callis.    I used to cut a lot of frozen sections from research animals to renal biopsies, skin punch biopsies and Mohs.  A couple things I will add are: 1) Make sure that all of the tissue being cut is surrounded by frozen section embedding media; and 2) make sure the section is no longer attached to the cutting blade edge before you pick up the section.  The epidermis will stick to the blade edge and pull out of the section 99% of the time.  The frozen section embedding media will provide a border and also help from separating the epidermal layer from the dermis.  Take the extra few seconds to run an applicator stick along the blade edge very lightly and separate the section from the blade and then pick up on a slide.  If you push the slide to close to the flat part of the blade the epidermis again will freeze to the blade and pull out of the section.

 

 

Date: Mon, 19 Jan 2009 13:52:41 -0500

From: "Shanu Mehta" <smehta <@t> magenbiosciences.com>

Subject: [Histonet] Problems with sectioning hairy skin

To: <histonet <@t> lists.utsouthwestern.edu>

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Hello All,

 

I have been sectioning some fresh frozen hairy human skin on the cryostat and I am having too much trouble getting decent sections. The sections seem to tear up and the epidermis & the dermis appear to separate.

 

My technique:

I embed dermis side down in OCT compound and then place the mold onto some dry ice until the mold solidifies. I then transfer the molds to a -80ºC freezer until they are ready to cut. Next I let the blocks come to cryostat temperature in the chamber. For cutting, I turn the block at a 90º angle meaning that both the dermis & the epidermis get cut in the same plane. I usually cut at a Chamber Temp of -19 & an Object Temp of -21. My cutting angle is between 3 & 5. I use low profile blades. I trim most of the fat that may be present in the skin, but there may be residual fat pockets that I may have missed!

 

This morning I talked to the technical staff at Leica and I was suggested to change the Chamber Temp to -21 to match that of the Object Temp. Also, I was asked to try with an angle of 5 or greater than 5 (as high as 8 or 9). I tried a range of temperatures and cutting angles, all in vain. I am still not happy with the quality of sections I am getting! 

 

Any suggestions on what I could do? I greatly appreciate any comments.

 

Thanks to all,

Shanu

 

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Shanu Mehta

Magen Biosciences

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Lee

 

Lee E. Dickey

Manager, Distribution and OEM Sales

Biosystems Division

 

Leica Biosystems St. Louis LLC

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