Three former co-workers of Michael J. Fox all have
Parkinson's disease, causing speculation that the disease
may have an environmental cause. Nobody knows what
causes Parkinson's disease. Scientists look for disease
clusters, hoping this will help them turn up clues that can
help with the search for a cure.
Fox and the three other people with Parkinson's disease were
among 125 people who in the late 1970s worked on a
Canadian television show called Leo & Me. Four cases among
125 people -- especially young people -- is highly suspicious.
Each year Parkinson's strikes only about 1 in 10,000 people,
nearly always much older people than the sitcom cast and
crew.
Fox is being treated in the U.S. His three co-workers are
being treated by Dr. Donald B. Calne, director of the
neurodegenerative disorders center at the University of
British Columbia in Vancouver. Calne says the odds of this
happening by chance are as little as 1 in 20,000. "We do
have a group of Parkinson's disease cases that seems to be
more than coincidental," Calne says. "These people worked
together here in Vancouver from 1976 to 1980. We want to
find as many other crew and cast members as we can and
see how their health is. We'll be looking at the building they
worked in to see if we can find any clues."
Dr. J. William Langston, founder and president of the
Parkinson's Institute in Sunnyvale, California, says he thinks
the Fox cluster is real. "Four cases in a small group in a short
period is very unlikely to be chance -- particularly because
they were young-onset cases," he says. "That is what really
puts it into statistical orbit. The younger cases are
extraordinarily rare."
Langston says Fox told him about the cluster of cases some
years ago, but it didn't become public knowledge until
recently, when it became part of a soon-to-be-aired
Canadian documentary. The program suggests that this
cluster may offer a clue to the cause of Parkinson's disease.
Calne and Langston think so, too -- and they've begun
hearing about other, similar Parkinson's clusters.
"As a result of all the media attention, we are getting very
interesting reports of other Parkinson?s disease clusters,"
Calne says. "We are interested in hearing of more. Right now
we are planning a strategy to try and prioritize investigation
of the various clusters we have heard about because of this
publicity. We feel it is important."
The most recent Parkinson's cluster occurred in the early
1980s, when cases of began appearing among young people
in San Francisco. Langston showed that these cases were
caused by a chemical contaminating synthetic heroin.
Another clue comes from the 1917 worldwide epidemic of
von Economo encephalitis. Years after recovering from this
disease -- thought to be caused by a now-extinct virus --
many patients developed Parkinson's disease, showing that
infections can leave a person vulnerable to Parkinson's.
Calne suspects something similar happened to Fox and his
co-workers. "We think there was probably quite a brief
exposure some years before symptoms occurred," Calne
says. "The way we see it is that probably some quite
common virus infects someone and -- because of a particular
state of susceptibility at that time -- it gets into the brain.
Maybe this is because they had another infection or a toxic
exposure. But they are not infective at all -- you can't catch
Parkinson's disease from a person who has it."
A cluster of cases occurred among members of the physics
department at the University of Pittsburgh when, over a 10-
year period, four professors were diagnosed with Parkinson's
disease. Neurologist Michael J. Zigmond, PhD, led the
investigation. "There's a couple of serious problems in trying
to understand these clusters," Zigmond says. "The first is, we
don't know what causes Parkinson's. You can measure
whatever you like, but we don't know what to look for. We
didn't find anything on the short list of compounds people
already feel there is reason to be concerned about. The
second problem -- and this is the case for the Fox cluster,
too -- is that there is a long delay between the time the
disease begins and the time it shows up as a clinical problem.
Whatever happened could have taken place on a single day
over a period of years. We just don't know enough."
Parkinson's disease affects a very specific set of brain cells
and symptoms of the disease only occur when about 80% of
these cells die off. "If you think of a battle, these nerve cells
are like soldiers," Calne says. "The event that causes
Parkinson's is like a battle. Some cells are killed outright,
some are unscathed, and some are wounded so that they die
prematurely. It is that premature death that leads to
Parkinson's disease."
To learn more,
click here.
A Parkinson?s patient has been treated with a transplant of
his own brain cells. The treatment cleared up the trembling
and rigid muscles that mark the disease. The patient, a
nuclear engineer and jet pilot, developed Parkinson?s in his
40s. More than two years after the experimental treatment,
he has no symptoms of Parkinson?s.
The researchers isolated and nurtured adult stem cells from
the patient?s brain, then re-injected them to restore normal
function. ?We definitely need to do more studies,? says Dr.
Michel Levesque of the Cedars-Sinai Medical Center in Los
Angeles, who led the study. ?This is the first case that shows
a promising technique may work. It is an experimental
procedure and has to be investigated further before it
becomes accepted procedure.?
Many different groups of researchers are experimenting to
see if brain cells damaged by Parkinson?s can be regenerated
using stem cells, the master cells that give rise to the
various different tissues in the body. Stem cells can come
from very early embryos, or can be found in a person?s own
tissues, although these are sometimes hard to obtain.
Levesque?s team drilled into the patient?s skull and removed
a piece of his brain. ?We took a tiny piece of cortex
measuring probably less than the size of a pea,? Levesque
says. ?What we extracted were neural stem cells or
progenitor cells.?
It?s hard to tell whether a cell is a stem cell, but they grew
the cells in special media, a kind of nurturing soup. They
checked to make sure at least some of the cells were
producing dopamine, the substance needed by Parkinson?s
patients, then injected them back into the patient?s brain.
PET scans of the man?s brain, which show brain function,
revealed that dopamine was being produced and used. ?At
three months there was a 58 percent increase,? Levesque
says.
The most puzzling finding is this: the man?s dopamine
production, as measured by PET scans, is back to where it
was when he was first treated, yet the symptoms of
Parkinson?s have not returned.
To learn about how cancer patient Russell Targ was healed,
read ?Heart of the Mind? and ?Miracles of Mind? by Russell
Targ and Jane Katra,
click here.
For more information, click here.
