Posted on 07/07/2006 11:55:27 PM PDT by neverdem
Alzheimer's disease, a dreaded specter for many elderly, is far more likely to strike individuals with Down syndrome. Now, a study with a mouse model of Down syndrome may explain why. The work hints at potential targets for future drugs that fend off dementia--in people with Down syndrome and in the general population too.
Down syndrome is caused by an extra copy of chromosome 21. It affects roughly 1 in 800 people, causing mild to moderate mental retardation and a range of other health problems, including early-onset dementia. By age 40, the brains of all people with Down syndrome develop the hallmark plaques and tangles of Alzheimer's and other signs of brain atrophy, autopsy studies have found. No one knows why this happens, but many researchers suspect this neurodegeneration has something to do with a gene called App. People with Down syndrome have an extra copy of this gene, which contributes to plaque formation in the brains of Alzheimer's patients. (The gene's normal function isn't clear).
The new research begins to explain why the extra copy of App kills neurons. A team led by Ahmad Salehi and William Mobley at Stanford University in California examined mice with extra copies of many of the genes found on human chromosome 21. As these mice age, a certain group of neurons deep in their brains dies off, and they experience cognitive declines. These neurons, which use the neurotransmitter acetylcholine, also die in Alzheimer's patients. When Salehi and colleagues knocked out the extra copy of the App gene in the Down syndrome mice, the cholinergic neurons survived. Additional experiments suggested that the extra copy of App kills the cholinergic neurons by disrupting their ability to transport a crucial growth factor, the team reports in the 6 July Neuron. Very few people in the general population have an extra copy of App, Salehi says, but the gene and its products are mishandled in Alzheimer's patients and could play a similar role in neurodegeneration.
"It's extremely elegant work," says David Patterson, a geneticist who studies neurodegenerative disease at the University of Denver in Colorado. "This paper will make an impact in both Down syndrome and Alzheimer's" research, predicts Roger Reeves, a geneticist at Johns Hopkins University in Baltimore, Maryland. "What this shows so nicely is that by reducing App, you can produce a much better outcome," Reeves says. Because App is also misregulated in Alzeheimer's patients, Reeves says it's reasonable to expect that turning down the gene's activity would be beneficial in Alzheimer's patients without Down syndrome. Salehi says he's now testing compounds that prevent the App gene from being translated into protein to see if they can prevent neurodegeneration in mice.
Overview of Down syndrome from the National Institute of Child Health and Development
Elegant?!? Describing it as "elegant" is the extreme of dispassionate!
When a bit of science is done quite convincingly, "elegant" is the word. Like a very beautiful woman, no one is going to argue about it.
marking my place
Elegant work?
Yes.
Because scientists of this type are not applied, or practical.
They are in love with the 'bug', and couldn't care less about curing disease.
The reason that cancer remains our number one killer is that scientists like to play with it, instead of killing it.
It also ensures they'll get grant money and have a job.
What we need is the equivalent of engineers in medicine.
As an analogy, mathematicians are also not applied scientists, and similarly have no interest nor care in the least if and how math solutions can ever be applied in the real world.
Engineers are the people that apply theoretical mathematics and physics, and create nuclear power plants, Ipods, and hybrid cars.
Engineers in medicine will prolong and improve life, and will do it in the manner of the Manhattan project - fast and furious.
Excellent analogy! Escellent analysis!~
Yeah, that's why medical science has yet to cure any diseases.
Dipstick.
I say, old boy, I think you've hit it!
Appreciated!
Having spent years associated with specialized scientists awarded multiple advanced degrees, it is a conclusion made from experience. A generalization to be sure, but you can bet on it.
I have yet to meet a more narcissistic, ignorant, close-minded, and useless group of individuals collected in any one place.
The exact opposite of what you would want and expect in the highly-educated charged with saving the world from disease.
Rather than being inspired, I found it depressing to think our future was in the hands of people with the character, integrity, and manner of a John Kerry.
You would be absolutely astounded at the lack of real world functionality, the childlike social skills, the inability to communicate, political gamesmanship, manipulation of experiments, fraudulent data, low self-esteem and insecurity, jealousy of the success of others, pompousity, sabotage of colleagues, stubbornness, inability to connect cause and effect, etc.
Truth was routinely submitted to other 'values' like money, envy, job security, recognition.
The culture breeds it, much like legal culture breeds vultures.
No, I wouldn't. I don't have real experience, but I've read a good deal about it. Despite my username, one of the more interesting books one the subject (the title of which escapes me) was on CJD, and whether prions exist or are the figment of a certain scientist hell-bent on a Nobel in Medicine. He got one, anyhow, but we may now be baying up entirely the wrong tree on the slow virus.
However, the pettiness and venality of the breed is, in part, what gives me hope for cures. The grant money and prestige involved is fabulous. I don't doubt there are thousands of scientist who would run over their own grandmas for a chance to cure a cancer definitively.
At any rate, a reasoned response to a rude post: very well played, Sir.
What wonderful news!
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