Which technique might also be used to demonstrate the same red-stained substance (amyloid) in tissue?

• A. Thioflavin T
• B. Silver staining
• C. Luxol fast blue
• D. Sudan Black

Answer: (A)

Amyloid’s detection relies on its cross-beta sheet structure, which specific dyes can recognize. Thioflavin T is a fluorescent dye that binds to the beta-pleated sheet of amyloid fibrils. When you view stained tissue sections with fluorescence, amyloid deposits light up, providing a clear signal for the same substance that Congo red reveals under polarized light. It serves as an effective alternative or complement to Congo red, helping confirm amyloid presence even when standard light staining is inconclusive. The other stains mentioned aren’t specific for amyloid: silver staining targets other structures, Luxol fast blue highlights myelin, and Sudan Black stains lipids.