Anita
The characteristic pathological lesions of Alzheimer's disease are neuritic
plaques and neurofibrillary tangles. Plaques consist of 3 major components -
amyloid fibrils, degenerating neurites and reactive glial cells. The
extracellular deposits of amyloid fibrils are composed of polypetides with a
secondary beta-pleated structure which gives rise to the charcteristic green
birefringence exhibited by all types of amyloid deposits after Congo red
staining.

Plaques can be demonstrated using a range of silver stains and
immunohistochemistry can be used to demonstrate the betaA4 protein. The
silver stain which seems to compare most favourably with
immunohistochemistry is the method of Garvey. (Garvey WJ,Fathi A. Rapid,
reliable and economic silver stain for neurofibrillary tangles and senile
plaques. J histotechnol 1991;14:39-42).
Best of luck
Roy Ellis
roy.ellis@imvs.sa.gov.au