Alzheimer's Disease

Introduction to Alzheimer’s Disease 1 1 Introduction to Alzheimer’s Disease David Allsop 1. Introduction In 1907, Alois Alzheimer published an account (1) of a 51-year-old female patient, Auguste D., who suffered from strong feelings of jealousy towards her husband, increased memory impairment, disorientation, hallucinations, and often loud and aggressive behavior. After four and a half years of rapidly deteriorating mental illness, Auguste D died in a completely demented state. Postmortem histological analysis of her brain using the Bielschowsky silver technique revealed dense bundles of unusual fibrils within nerve cells (neurofibrillary tangles or NFTs) and numerous focal lesions within the cerebral cortex, subsequently named “senile plaques” by Simchowicz (2) (Fig. 1). This combination of progressive presenile dementia with senile plaques and neurofibrillary tangles came to be known as Alzheimer’s disease (AD), a term that was later broadened to include senile forms of dementia with similar neuropathological findings. It was Divry (3) who first demonstrated the presence of amyloid at the center of the senile plaque, by means of Congo red staining. All amyloid deposits were originally thought to be starch-like in nature (hence the name), but it is now apparent that they are formed from a variety of different peptides and proteins (the latest count being 18). All amyloid share the property of a characteristic birefringence under polarized light after staining with Congo red dye, which is due to the presence of well-ordered 10 nm fibrils. The underlying protein component