[Histonet] Inquiry on Tissue Softening for Microtomy

[John Kiernan]

   If you apply the ammonia to the cut surface of the paraffin block, I suspect that it softens the tissue in the same way as applying water: by entering interstices of the tissue that are not occupied by paraffin molecules.
   I never tried ammonia for this purpose but in the 1960s to early '70s I occasionally used a proprietary product called Mollifex, which I see is still sold. In 1972 or '73 an elderly technician told me that water was just as good, and I soon found out that he was right. Indeed, water had the advantage of working in 15-30 minutes rather than taking several hours.
John Kiernan
Emeritus, UWO, London, Canada
https://publish.uwo.ca/~jkiernan/
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________________________________
From: IGNACIO GONZÁLEZ MASSONI via Histonet <histonet at lists.utsouthwestern.edu>
Sent: May 10, 2024 8:53 PM
To: histonet at lists.utsouthwestern.edu <histonet at lists.utsouthwestern.edu>
Subject: [Histonet] Inquiry on Tissue Softening for Microtomy

Dear friends at Histonet,

I hope this message finds you well. I am reaching out to seek your expertise on a matter that has piqued my interest in the field of histology.

I am currently delving into the process of preparing FFPE (formalin-fixed, paraffin-embedded) tissues for microtomy. Specifically, I am curious about the role of ammonia in softening these tissues before sectioning. From my understanding, ammonia serves as an alkaline agent that helps neutralize formalin's effects and facilitates the removal of paraffin, thus aiding in the softening of the tissue.

However, I would greatly appreciate if you could provide a more detailed explanation of the chemical interactions at play here. How exactly does ammonia interact with the tissue components to achieve the desired softening effect? Moreover, are there any best practices or safety precautions that one should be aware of when using ammonia in this context?

Your insights on this topic would be invaluable to me and would greatly enhance my understanding of the intricacies involved in histological preparations.

Thank you for your time and assistance.

Warm regards from Santiago of Chile

Ignacio, Medical Technologist
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