Dr. Ray Dorsey
speaker
51 appearances
1 recordings
1 series
first heard Dec 2024
last heard Dec 2024
Dr. Ray Dorsey’s voice in public audio — every appearance, attributed to the second.
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So I think the three environmental toxicants that are principally responsible for the rise in Parkinson's disease are certain pesticides, the poster child for them being a pesticide called Paraquat, widely used as a weed killer. The second are commonly used dry cleaning chemicals, including this one called trichloroethylene.
And the third is one familiar to Southern Californians, and that's air pollution.
So trichloroethylene, or TCE, is a really, really simple molecule. So your listeners all know that water is H2O, which means it just has three atoms, two hydrogens, and one oxygen. Trichloroethylene is very simple. It's got six atoms. It's got two carbon atoms in black, one hydrogen atom in white, and three chlorine atoms in green, hence its name, trichloroethylene.
This chemical was initially developed in 1864, so I think at the time of President Abraham Lincoln was the president, and it's been used since the 1920s, so since shortly after World War II. And it's been used in everything. It's been used to decaffeinate coffee. It was found in Senko or other decaffeinated coffees in the 1970s.
It's been used to degrease metal, and it's been used to dry clean clothes. It's found in carpet cleaners. It's found in gun cleaners. It's found in typewriter correction fluid. It's found in a wide variety of consumer goods. And this chemical is known to cause cancer. There's no question about that. The EPA says it's carcinogenic by all routes of exposure.
The World Health Organization says that it causes cancer. And yesterday, the EPA long-lasted proposed a ban on nearly all uses of trichloroethylene in the United States. And this ban would go in effect in a year. And I think by taking that action, they are preventing generations of individuals from developing cancer in the future.
And I think they're also likely preventing generations of individuals from developing Parkinson's disease in the future. However, the Problem is not just the use of trichloroethylene, which in the 1970s, it's estimated that 10 million Americans worked with this in semiconductor industry, in mechanics, in printers and painters and taxidermists and varnish workers all worked with it.
But there are numerous thousands of contaminated sites, including contaminated sites in Newport Beach, California, where I went to high school and not too far from where you're sitting right now in Southern California. and in sites in Woburn, Massachusetts, north of Massachusetts, north of Boston.
There are dozens of dry, at least a dozen dry cleaning sites in Rochester, New York, that are contaminated with this chemical and a closely related chemical. So these sites are all around us. But the good news is EPA has banned future uses of it. This proposed ban would go in effect in a year, is my understanding.
But we still have more work to do to contain, remediate, and clean up these contaminated sites throughout the country.
Yeah, so if you think about the brain, it's basically an energy-guzzling organ. The brain's only about 3% of our body's weight, but it consumes 20% of our blood's glucose or energy supplies. And within the brain, there are many different kinds of cells. And the cell that consumes the most energy are the nerve cells, also called neurons. And many of these neurons are chock full of mitochondria.
And certain cells in the brain that are responsible for Parkinson's disease and produce a chemical called dopamine are basically just big garbage bags that are filled with jelly beans. And those jelly beans are mitochondria. And if you think about it, these pesticides, especially paraquat, trichloroethylene, and air pollution are all known to damage mitochondria.
And they actually kind of bypass our normal protective mechanisms that we have. We have the gut, we have the blood brain barrier, but all of these guys are inhaled. And so this could be a way of exploiting the front door to our brain that these environmental toxins, all of which we know damage the energy producing parts of cells.
And we know that the cells that are lost in Parkinson's disease have huge energy demands. and that these things are inhaled. So I think you can weave together a story by which these toxicants are causing many people to have, likely many people to have Parkinson's disease.
You're right, I wasn't, or maybe I must have missed it, because I don't think I ever learned anything. I don't think I even heard about trichloroethylene when I was in medical school.
The real gift is I had a sabbatical about five or six years ago, and I spent a lot of time reading the work of my colleague, a woman, Dr. Caroline Tanner, who's a professor of neurology and an epidemiologist at University of California, San Francisco. And she and her colleagues had done a study looking at TCE 10 years ago.
And finding that the rates of rates of Parkinson's among twins who had either worked with it or had hobby exposure to TCE were increased rates of Parkinson's by 500 percent.
And then research from animal from other researchers, Don Gash in Kentucky and others have showed that when you feed TCE to laboratory mice or rats, they develop the clinical and pathological features of Parkinson's and they lose those dopamine molecules. producing nerve cells in the brain.
And then I read a lot more of Dr. Tanner's work showing that in the late 1990s, that twin studies suggested that environmental causes were the predominant explanation for people who develop Parkinson's disease. She showed that exposure to Paraquat 10 years ago among farmers was associated with 150% increased risk of developing Parkinson's disease.
Dr. Jeff Bronstein and Dr. Pieta Ritz at UCLA, not too far from where you're sitting, did research showing that air pollution and well water drinking were associated with Parkinson's disease. So I had the gift of a sabbatical in which I read a lot of literature. And the more I read, you know, a lot of time you go down rabbit holes. But this time you kept going and you kept going and kept going.
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