- Hello Jeff - What is really going on with this unidentified
bovine (polio-like) condition in cattle? Is this just the beginning? Could
it be some sort of veterinary Alzheimer's Disease? Is the condition related
to a new form of BSE/Mad Cow Disease?
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- If cattle with this ailment are allowed to enter the
food chain, will humans be at risk? What about pet food?
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- I feel that we have another very, very serious situation.
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- Patricia
Alzheimer's Disease May Originate In The Brain's White Matter
- Science Daily.com
- 6-17-4
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- Changes in the brain's white matter may play a major
role in the onset of Alzheimer's disease, whose baffling origin has traditionally
been blamed on the gray matter. The new findings could provide a fresh
direction for Alzheimer's research in this neglected part of the brain,
offering the potential for early diagnosis and enhanced therapies.
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- The results are reported in the Sept. 17 print edition
of Biochemistry, a peer-reviewed journal of the American Chemical Society,
the world's largest scientific society.
"Alzheimer's disease is conventionally considered a disease of the
brain gray matter because its most prominent consequence is severe memory
loss," says Alex Roher, M.D., Ph.D., director of the Sun Health Research
Institute in Sun City, Ariz., and lead author of the paper. The overwhelming
majority of Alzheimer's research has focused on gray matter, despite the
fact that white matter makes up about 50 percent of total brain tissue
and is substantially altered during Alzheimer's progression, Roher says.
The prevailing theory has been that changes in the white matter are simply
effects of the initial gray matter alterations, but Roher's research suggests
the opposite may be the case: white matter changes could come first.
In the brain, a layer of gray tissue surrounds a whitish core, like the
peel of an orange around its juicy interior. The gray exterior consists
of neurons and their associated neurites " short protrusions that
communicate with neighboring neurons. This gray matter essentially acts
as the brain's central processor.
Neurons send messages through the brain and to the central nervous system
by transmitting electrical signals over long appendages called axons. Axons
are covered with an insulating fatty sheath, known as myelin, which speeds
up the transmission of the signals. Myelin is the major component of white
matter.
"Ours is the first study to present a detailed biochemical analysis
of white matter tissue of Alzheimer's disease patients," Roher says.
The researchers studied brain tissue from two groups of people: those with
autopsy-diagnosed Alzheimer's disease, and those who died from other causes
with no associated dementia.
The study revealed that the total amounts of protein, lipids and cholesterol
were significantly reduced in the myelin of Alzheimer's patients in comparison
to the control group. This erosion of the myelin sheath is referred to
as demyelination.
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- "These profound white matter alterations undoubtedly
contribute to the origin and development of Alzheimer's disease, and might
possibly be the initiating step," Roher says. There are multiple reasons
for arriving at this conclusion, according to Roher, but two in particular
stand out.
-
- First, previous studies have demonstrated that patients
with pre-clinical Alzheimer's disease show deterioration in the white matter
before the gray matter. Second, the current study suggests that white matter
degeneration might be caused by a disease of the oligodendrocytes, whose
main job is to produce the myelin sheath. A defective myelin coating could
leave the axons unprotected, resulting in serious disturbances in nerve
conduction and damage to brain functions, Roher says.
-
- Because neurons in the gray matter are vital to cognitive
activity, scientists have generally assumed that Alzheimer,s disease "
with its memory loss and other cognitive debilitations " must begin
in the gray matter.
-
- But Roher says the white matter is just as critical to
cognitive function. White matter axons play a major role in controlling
mental activities like emotion, and all mental functions are fully expressed
only when the axons are transmitting properly.
-
- An analogy can be drawn from the recent energy crisis
in California, Roher says. One of the many issues facing Californians was
a short supply of power " attributable, in part, to an unusually cold
winter and a dry summer at hydroelectric dams. A suggested solution was
to increase the output of coal-fired plants. But the state's infrastructure
" power lines, transfer stations, etc. " would be unable to carry
the extra power, thus negating any potential benefits. So it is with the
brain's transmission infrastructure: the white matter.
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- The researchers found two other interesting relationships.
Women tended to have more alterations in their white matter than men, a
finding consistent with the general predominance of Alzheimer's cases in
women. An increased level of apolipoprotein E, which has been associated
with higher risk of Alzheimer's, also showed a correlation with greater
demyelination.
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- Roher says he hopes that Alzheimer's researchers will
expand their area of interest to include white matter: "Only if the
full extent of Alzheimer's disease pathology is known will present attempts
to intervene in the progression of the disease have any reasonable chance
of success."
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- This study was partially supported by the State of Arizona
Alzheimer's Disease Research Center and by the National Institutes of Health.
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- Alex Roher, M.D., Ph.D., is director of the Sun Health
Research Institute in Sun City, Arizona.
-
- This story has been adapted from a news release issued
by American Chemical Society.
-
- http://www.sciencedaily.com/releases/2002/09/020919071511.htm
-
-
- Comment
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- From Bill Hamilton
- 6-18-4
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- Jeff,
-
- My wife and I watched a special program on our PBS station
about Alzheimer's disease and the current research which indicated that
its cause is most probably the accumulation of toxic beta amyloids in the
brain and that a drug has finally been produced that seems to target these
beta amyloids and flush them out.
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- See: http://my.webmd.com/content/article/29/1728_63331
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- Sincerely
-
- Bill Hamilton
- AstroScience Research
- Theory guides. Experiment decides.
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