Untangling the mysteries of Alzheimer's One of the most
distinctive signs of the development of Alzheimer's disease is a
change in the behavior of a protein that neuroscientists call
tau. In normal brains, tau is present in individual units
essential to neuron health. In the cells of Alzheimer's brains,
by contrast, tau proteins aggregate into twisted structures
known as "neurofibrillary tangles." These tangles are considered
a hallmark of the disease, but their precise role in Alzheimer's
pathology has long been a point of contention among researchers.
Now, University of Texas Medical Branch at Galveston researchers
have found new evidence that confirms the significance of tau to
Alzheimer's. Instead of focusing on tangles, however, their work
highlights the intermediary steps between a single tau protein
unit and a neurofibrillary tangle assemblages of two, three,
four, or more tau proteins known as "oligomers," which they
believe are the most toxic entities in Alzheimer's. "What we
discovered is that there