Re: [Histonet] fried specimens

From:Rene J Buesa

  As usual the problem you mention has several solutions, meaning several causes. Let me see if can be of some assistance:
  1- I have no explanation as to why one half looks OK and the other not, but it could be something with the sample itself and if it was just partially immersed in the fixative; one part would be with the fixative and the other dehydrating in the air;
  2-a 12 hours protocol for small biopsies is too much; I understand that the HT has to rest and that finishing to load the VIPs at 6PM would be advantageous to have a 12 hours protocol to get the finished cassettes at 6AM, but the dehydration steps could be too long. I think it would be advantageous to dehydrate in graded steps (starting at 70% EthOL and go up to the absolute) but that all those steps take less time than they have now. I think it would preferable to have the processed tissue sitting in melted paraffin for more time than now, than having them too long in the dehydratants.
  3- you could also use the tissue processors on delay in a way that the specimens sit in the first formalin station completing the fixation before starting a shorter protocol that will end also at 6AM with less time in each station and without having to sit in paraffin until you start embedding;
  4- you also could change to a less "violent" dehydrating/infiltrating medium, like mineral oil. When I changed to MO the sporadic problems we had desappeared totally (I could send you the protocol if you want).
  5- I also realize that using sponges is faster, but you could get the problems you are having. I used to try 2 other approaches: wrap the biopsies in tissue paper (somewhat laborious) or use pieces of filter paper, precut to cassette size and used as if they were the sponges. Both gave me good results.
  6- never overfill your tissue processors and since you have up to 550 blocks / day it is evident that you have more than 1 tissue processor. Dedicate 1 for a shorter protocol for small specimens (the smaller if they are fewer small specimens of the larger if it is the contrary).
  To me your problems either start at the sampling step (and you could do not much about it) or while processing (and in that aspect you are the "master of your destiny"!)
  Hope this will help you!
  René J.

kristen arvidson  wrote:

We have had problems with our specimens (all derm) on and off for several years. They get hard and fried looking. The problem is so sporadic. The weird thing is only one piece of the biopsy will be affected(ie. one half of a bisected punch looks fried the other normal). We use some sponges when necessary for smaller pieces (I've heard they can cause problems). We are on a 12 hour processing schedule (which we could probably reduce). We have older VIP processors. We are running 350-550 blocks per day so our processors get pretty full. We have recently lower our paraffin temps and we try to keep spaces between our cassettes as much as possible. We check all reagent levels to make sure they are full. So my questions is 'what else are we missing?' Also, can anyone help me with ideas on shorter processing schedules for skin?

Thanks for any input!!

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