Cooling on ice for 10-15 min renders the block cool enough for trimming and consecutive cutting without the need of a freezing spray. We use cooling devices at -15 degrees. They have usually a nice snow-surface, that gives the block some moisture during cooling. Especially blocks, that have to be recut, get advantage of this and are easier to cut.
I think freezing sprays render the block too cool and provide no evan temperature throughout the block. A completly homogenously cool block is better to cut. I also don't like the interrupted workflow with first trimming, then putting away and then cutting again. - but- I work with a sliding microtome and trimming goes really fast. Gudrun Lang -----Ursprüngliche Nachricht----- Von: histonet-boun...@lists.utsouthwestern.edu [mailto:histonet-boun...@lists.utsouthwestern.edu] Im Auftrag von Jenny Vega Gesendet: Samstag, 29. September 2012 04:40 An: histonet@lists.utsouthwestern.edu Betreff: [Histonet] Cooling paraffin blocks with ice VS. Freezing Spray 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. _______________________________________________ Histonet mailing list Histonet@lists.utsouthwestern.edu http://lists.utsouthwestern.edu/mailman/listinfo/histonet _______________________________________________ Histonet mailing list Histonet@lists.utsouthwestern.edu http://lists.utsouthwestern.edu/mailman/listinfo/histonet