[Histonet] Cooling paraffin blocks with ice VS. Freezing Spray

[C.D.G.]

Freezing spray is better if you use it with discretion. Freezing too much could render sections with artifacts 
like partial "holes" on the section, so you must use it with care and not always, as you stated, some
pieces cut better if you don't chill them at all.
The use of ice is possible,but I saw that many times, the drop of water over the blade holder unit, leads to a 
slow but progressive corrosion of some of the components that are indispensable for an accurately sectioning work.
Try to begin using the spray taking care of not overcool the materials and you'll soon  be feeling comfortable
with this method.
My best regards ,
Carlos.-
  *********** REPLY SEPARATOR  ***********

On 28/09/2012 at 10:39 p.m. Jenny Vega wrote:

>I want to know what is your preferred method for cutting paraffin blocks
>in
>the microtome everyday. At work I am having issues with my supervisor
>because we have different ways of doing things like for example she doesn't
>like to use the technique where you first trim the tissue, cool it on an
>ice tray and then make a section. That is how I learned to cut in histotech
>school. Instead she just trims and cuts the blocks at 4 microns one by one
>using the same blade until it wears out and she cools the blocks only
>freezing spray.
>
>She doesn't like to cool the blocks on an ice tray because according to her
>is a waste of time and that is why I have to use her technique but
>unfortunately some blocks are extremely difficult to cut and I have to go
>back to my preferred  technique. I feel I get better sections without
>wrinkles when I chill and soak the blocks on ice for a couple of minutes. I
>sometimes use freeze spray when the blocks get warm but when I cool them
>with ice I don't need to use freeze spray that much. Her technique works
>but is more successful when the blocks are well processed. I have
>difficulty getting completed sections  this way and spend more time trying
>to get the perfect section. Sometimes I have my good days but other times
>is tedious using this technique. Another thing I notice is that the blades
>get worn down quicker when you use them to trim and section. I prefer two
>separate blades, one to trim and the other one to section. I feel they stay
>sharp for more time.
>
>She discourages the use of ice but then complains that we are running out
>of freezing spray for the frozen sections too quickly which doesn't make
>sense. It is obvious that if she encourages to use ice to cool blocks then
>we will be using less freezing spray.
>
>Another reason she discourages the use of ice is that some blocks are not
>meant to be chilled which is pretty understandable. I cannot cool small
>biopsies such as gastric and skin and bone because they can get too hard
>and tear off from the block so I avoid that but I prefer to cool breast and
>colon biopsies on ice because these are fatty tissue that can be tedious to
>cut even when relying only on freezing spray.
>
>
>
>I want to know if it's completely acceptable for me to prefer the trim,
>cool on ice and section technique and if you feel is a waste of time
>comparing it with other ways of cutting such as the one I mentioned.
>
>
>
>Thanks.
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