Tracing amyloid in Alzheimer's

Chemistry World ^ | 14 October 2009 | Phil Taylor

[neverdem]

A diagnostic compound that allows researchers to look into the brains of Alzheimer's patients will be used for the first time to gauge the effects of an experimental therapy for the disease. 

Called florbetaben, the diagnostic could also provide important insights into the role of beta amyloid, a protein that accumulates into plaques in the brains of patients with Alzheimer's disease and has been shown to be toxic to nerve cells. 

The compound is an 18F-radiolabelled tracer that binds specifically to deposits of beta amyloid, and can be measured using positron emission tomography (PET), a nuclear imaging technique which produces a three-dimensional image of functional processes in the body. 

In living patients, diagnosis of Alzheimer's currently relies on a mix of cognitive testing and magnetic resonance imaging (MRI) and computed tomography (CT) scans to exclude other forms of dementia, but is only 70 to 80 per cent reliable. 

"A safe diagnosis of Alzheimer's is currently only possible post-mortem - florbetaben could help differentiate people with Alzheimer's from healthy individuals"

'MRI and CT only allow for the imaging of anatomic compositions of the body, such as organs,' a spokesperson for Bayer Schering Pharma, the company behind the development of florbetaben, told Chemistry World. 'More recently, PET scans are increasingly being read alongside CT or MRI to allow anatomic and structural or molecular information to be gathered at the same time.' 

A definitive diagnosis of Alzheimer's relies on the presence of beta amyloid plaques and other hallmarks of the disease in brain tissue samples examined under the microscope.  

'A safe diagnosis of [Alzheimer's] is currently only possible post-mortem,' the spokesperson commented. 

Data presented earlier this year from a Phase II trial suggested florbetaben could be used to differentiate people with Alzheimer's from healthy volunteers of the same age. 

In the latest study, florbetaben will be used to see whether a vaccine developed by Swiss company AC Immune, designed to stimulate the immune system to break down amyloid plaques in the brain, is having the expected effect. 

The vaccine has already shown it can reduce plaque size and improve memory in animal models of Alzheimer's disease, according to Dr. Andrea Pfeifer, AC Immune's chief executive. 

'Visualising the deposition of beta amyloid that is targeted by our vaccine can be an important parameter for dose selection, and will provide useful complementary data,' she says, adding that developing diagnostics alongside therapeutics is an emerging trend in the pharmaceutical sector. 

Meanwhile, florbetaben could also be useful in establishing once and for all the role of beta amyloid in Alzheimer's disease. 

In September, Chemistry World  reported the results of a study which found that a compound called dimebolin had a beneficial effect on Alzheimer's symptoms, despite increasing levels of beta amyloid. That prompted suggestions that other forms of the protein, such as soluble amyloid oligomers, may be more neurotoxic than plaques. 

It may be too soon to reject the prevailing 'amyloid hypothesis', but tools like florbetaben could be invaluable in establishing the role of the protein once and for all. 

'A good diagnostic assay should help to evaluate the effect of new treatments in clinical trials better, as well as improve correlation of results with existing pathological and memory markers,' commented the spokesperson.  

 

 

Also of interest

New drug turns Alzheimer's theory on its head

22 July 2009

An antihistamine that improves Alzheimer's symptoms has raised questions about our understanding of the disease

New technique probes Alzheimer's aggregates

14 June 2009

Scientists probe synthetic proteins to identify key toxic species responsible for Alzheimer's plaques

A metal trap to stop Alzheimer's

30 July 2008

Promising drug halts a metal-mediated chemical reaction in the brain

[texas booster]

As always, depends on testing.

I expect that it will be Q1 before betas are released.

[David Park]

I have about 8 PCs, but I only have two computers running F@H right now. One has four 9800GX2 video cards, and one has two 8800GS cards. I don’t do any CPU folding. I used to also fold on my PS3, but the power usage wasn’t worth it.

I’m happy that the cold weather is finally here—I don’t need to turn on the heat in the winter because the PCs heat my condo.

[FourtySeven]

Hi All,

I’m happily plugging away with the last computer I have left to run the program, my old PC that is doing nothing else. It has an old version of the systray client, and I was wondering if anyone knew:

If I download the new one, is the old one automatically replaced, or do I need to uninstall the old one? Also, if I do get the new client, do I loose the work unit it’s currently working on?

Thanks,

[texas booster]

It looks like you will have a work unit finishing in the next week. Look here to see when it is credited:

http://folding.extremeoverclocking.com/user_summary.php?s=&u=168197

I would leave the system on 24/7 until you see the work unit finish, probably just another day or so.

If you are running the system tray client, after this WU completes, stop the client, and erase it all. IIRC, there is a setting under Configure” that allows the WU to stop after completion. If you can't find it, just erase it all.

Load the most recent from here:

http://folding.stanford.edu/English/Download

The current system tray client is 6.23. It is faster than the 5.2x version and allow you to crunch more varieties of molecules. The viewer is also great.

How long have you been folding? Four or five years now? That's great.

Please ping us if we can help!

[colinhester]

I remember when people were hitting 3k ppd. It was like they were from the mother-ship. Like TB said, graphic cards are the only way to rack up some serious points. Even something as mundane as a 9600GSO, when overclocked, can easily produce 4k ppd. For the bigger cards, you’ll need to upgrade the computer’s power supply, but that’s a real easy change.

A while back, SazanEyes sent a link to me describing his rig. I’ll see if I can find it. It’s a freakin’ beast!!!!

[David Park]

Here’s the link to the machine that generates most of my points:
http://www.sazan.net/dpark/gauri.shtml

I don’t have any pictures of my other box online yet, but I do have various computer pictures here:
http://s722.photobucket.com/albums/ww222/sazaneyes/

Those machines are running GPUGRID and various other distributed computing projects.

[FourtySeven]

Thanks I’ll check it tonight.

Yes I’ve been folding since this project began on FR. When was that, 5 years ago already? If I had been asked before, I wouldn’t have said more than 4. It doesn’t seem that long.