What is the effect of 'over-fixation' in formalin?
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Correct answer: Tissue hardens and becomes brittle, masking antigenicity
While under-fixation leads to decay, over-fixation (especially in formalin) can cause tissue brittleness and excessive cross-linking of proteins. This cross-linking can mask epitopes, requiring antigen retrieval steps before immunohistochemistry.
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More Tissue Processing questions
- Which reagent is used as a 'secondary fixative' for electron microscopy to provide high contrast?
- What is the primary advantage of using a vacuum during tissue processing?
- Which of the following fixatives contains picric acid and is excellent for preserving glycogen but causes significant shrinkage?
- What is the 'refractive index' (RI) and why is it relevant in the clearing step?
- In a routine overnight processing schedule, which stage is usually the longest?
- Which of the following is a 'de-fatting' agent that can be used for very fatty tissues like breast?