Congo red staining for amyloid under polarized light shows: September 2007
Correct Answer: Green birefringence
Description: Ans. D: Green birefringenceThe traditional way of identifying amyloid in tissue sections has been staining with Congo red and demonstration of green birefringence under crossed polarizers.The original method of Congo red staining was described by Bennhold in 1922.The most common modification in the above technique is the alkaline Congo red method described by Puchtler and coworkers in 1962.Specificity is improved by using freshly prepared stain and a staining solution fully saturated with sodium chloride. Amyloid proteins can be fuher distinguished by autoclaving or by treating the tissue with potassium permanganate or alkaline guanidine.Other methods of detection of amyloid include fluorescent stains, e.g., thioflavin T or S, and metachromatic stains such as crystal violet.Immunofluorescence and immunoperoxidase methods are used to identify and classify amyloid proteins in tissues. Antibodies against the P component, proteins AA and AL and FAP have been used with great precision.Due to cross-reactivity, these methods do not differentiate between some types of familial and senile systemic amyloidosis
Category:
Pathology
Get More
Subject Mock Tests
Practice with over 200,000 questions from various medical subjects and improve your knowledge.
Attempt a mock test nowMock Exam
Take an exam with 100 random questions selected from all subjects to test your knowledge.
Coming SoonGet More
Subject Mock Tests
Try practicing mock tests with over 200,000 questions from various medical subjects.
Attempt a mock test now