Re: coated slides

From:Gayle Callis

Overdrying can be just as much a problem since cartilage has a high content
of water that when overdehydrated, causes this to curl off slides first.
Make sure you are getting perfectly flat sections by using an extremely
sharp blade.  We used to change blade edge every other block or so to
insure perfectly flat, no compression in sections. I have been known to
change blade edge between blocks!  

Plus charge slides work fine, drained well, then laid FLAT and dried at 37C
to 40C overnight or longer, we did not go to a 60C oven - ever.  

You can coat slides with chrome alum/gelatin subbing solution, air dry and
use slides.  We used 100 bloom gelatin and for problem bones (really big
sheep, distal tibia) the sections were floated on a waterbath containing
chrome alum solution but with 275 bloom gelatin.  Beware, gelatin can cause
unsightly blue background on H&E stain.  The large bloom number means the
gelatin is a larger molecule, made from swine collagen, check out Sigma
catalog.  We never used household gelatin, never knew what source of
gelatin was, from pig, cow, etc nor bloom size. 

Dissolve 10 g (100 or 275 bloom) gelatin in 1 liter WARM distilled water,
add 1 gm chromium
potassium sulfate, stir until dissolved, add a thymol crystal.  Final
concentration of gelatin is 1%.  You can also make this a 0.5% solution if
you wish.  You can add 10 mls of this solution to a 2 liter water bath OR
coat slides for future use.  Dip clean glass slides in this solution, drain
so excess flows towards label, air dry and store in a cool, dry box.  If
background is a problem you can dip coated slides a few times in neutral
buffered formalin, rinse well and air dry.  The formalin cross links some
of the gelatin protein on slide, reduces background during staining, but
allows problem section to stay on the slide.  

At 08:48 AM 8/1/2003 -0400, you wrote:
>Hi, 
>I am having problems with tissue staying on my slides after drying overnight
>in 37C oven and then one more night in a 60C oven.  The tissue is chicken
>leg knee joints.   They are formalin fixed, EDTA decaled, and paraffin
>embedded samples.  I think that coated slides may help.  Does anyone have a
>simple protocol for making coated slides to help this tissue stick?  
>Thanks in advance for the help.
>
>Loralee Gehan
>University of Rochester
>  
>
>
>
>
Gayle Callis
MT,HT,HTL(ASCP)
Research Histopathology Supervisor
Veterinary Molecular Biology - Marsh Lab
Montana State University - Bozeman
S. 19th and Lincoln St
Bozeman MT 59717-3610

406 994-6367 (lab with voice mail)
406 994-4303 (FAX)

email: gcallis@montana.edu




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