Alzheimer

Delusions and hallucinations are also common in the late stages of the disease (Roberts 1999). The other important directly observable hallmarks of Alzheimer's disease are the clusters of protein in the brain (George-Hyslop 2000). These accumulations occur both inside nerve cells and between the nerve cells (George-Hyslop 2000). The high density of these accumulations in Alzheimer's patients is distinctive and strongly correlates with the severity of dementia (George-Hyslop 2000). In Alzheimer's patients, certain regions of brain, including the hippocampus and cortex, lose neurons; and the normally complex surface of the brain ultimately wastes away (George-Hyslop 2000). (Figure 1 compares the brain of a normal individual with the brain of an Alzheimer's patient (George-Hyslop 2000)). All of the above are the most important symptoms in trying to diagnose Alzheimer's disease. .
             In this paragraph I will discuss two main causes of Alzheimer's disease: amyloid protein (amyloid plaques) and tau protein. Amyloid protein clusters are found between the nerve cells while tau protein tangles are found inside the nerve cells (George-Hyslop 2000). The main component of an amyloid protein is a peptide made up of 40 or 42 amino acids (George-Hyslop 2000). This peptide is known as beta-amyloid peptide and this originates from a longer protein called beta amyloid precursor protein, or ßAPP (George-Hyslop 2000). The gene from which this longer protein is formed is known as ßAPP gene (George-Hyslop 2000). Researchers have proven that abnormal processing of ßAPP (due to mutations in ßAPP gene) or activity of ßAPP causes the Alzheimer's disease (Travis 2000). In course of its life ßAPP is cut in one of two ways to produce ß-amyloid peptide which is the main component of the amyloid plaques (George-Hyslop 2000). The first way in which ßAPP molecule is cut is totally harmless where it is first cleaved by an enzyme called alpha-secretase and then by another enzyme called gamma-secretase (George-Hyslop 2000).