Histotechnology I- Miscellaneous
Question No. 17. The Answer is: (B) Feulgen reaction.
Discussion: Gallocyanin-chrome alum method will stain both DNA and RNA dark blue and, therefore, cannot provide a good estimate on the amount of DNA in the cell. The same is true for hematoxylin. Thioflavine S stain can be used to demonstrate amyloid deposition and must be visualized with a fluorescent microscope. It cannot be used to estimate the amount of DNA in tissue sections. Solochrome cyanine method can be used to differentiate osteoid from newly laid-down bone and older bone but does not stain DNA specifically. Feulgen reaction stains DNA red-purple and the cytoplasm green and is a widely accepted method to demonstrate DNA on histologic sections.