But investigators still have a long way to go. "It's one thing to distinguish the sick group from the healthy group and another to see if you can predict from the healthy group who gets the disease," Kennedy said. "That's the real proof of the pudding."
A second study, from researchers at Washington University in St. Louis, confirmed previous findings: that the more amyloid there is in the brain (as measured by PET scans), the less beta amyloid 42 there is in cerebrospinal fluid (CSF). Beta amyloid 42 is an extra-"sticky" type of amyloid protein which accumulates and forms plaques. The theory is that measurements of beta amyloid 42 in spinal fluid could serve as a marker for Alzheimer's disease.
Another study, this time from a team in Ireland and in Germany, found that individuals with mild cognitive impairment (MCI), often considered a transitional stage between normal cognitive functioning and Alzheimer's, had elevated levels of beta-secretase (BACE1) activity in the brain when compared both to healthy people and people with Alzheimer's.
Finally, a fourth study showed that a certain radioactive compound or tracer, 18F-AV-45, may have potential in the diagnosis and early detection of Alzheimer's when used with PET scans. Trials of the substance, conducted by Philadelphia-based Avid Radiopharmaceuticals Inc., are ongoing.
For more on Alzheimer's, visit the Alzheimer's Association.
SOURCES: Gary J. Kennedy, M.D., director, geriatric psychiatry, Montefiore Medical Center, New York City; presentations, 2008 International Conference on Alzheimer's Disease, Chicago
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