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Tuesday, 20 June, 2000, 00:00 GMT 01:00 UK
'First real test' for Alzheimer's
brain scanner
The dye shows up on a brain scan
Scientists claim to have developed a test allowing an earlier confirmation of Alzheimer's disease.

Until now, the only way of making a definite diagnosis was by looking at the brain in detail after death.

The test, if successful, could mean that Alzheimer's patients could be placed on treatments earlier, before their condition has declined further.

This would keep them in a less badly-affected state for longer.

It would also allow scientists to monitor the success or otherwise of any new treatments for Alzheimer's.

The research team, from the Pennsylvania School of Medicine in the US, has found a chemical molecule which can enter the brain and bind with the "plaques" which form in brain tissue - a key feature of the disease.

So far their experiments have only been carried out in animals, but the team is confident that their results will translate into humans.

Blood brain barrier

The key to success is breaching the "blood-brain barrier", which is designed to stop harmful chemicals reaching the brain from the rest of the body.

Normally the only way to confirm Alzheimer's is after death
The team is using a "stealth" molecule, called BSB, which can pass this, and go on to bind with the plaques.

This dye-like molecule then shows up on certain types of brain scan, showing exactly how much plaque is present in the brain.

The work has been successfully carried out in mice which are prone to developing similar plaques.

The molecule was injected into the mouse's vein, and managed to reach the plaques in the brain, described by the researchers as the "Holy Grail".

Dr Virginia Lee, leading the research, said: "This is definitely proof of concept.

"This is an essential first step for the development of an antemortem diagnostic for Alzheimer's disease."

The team plans to work on to improve the ability of BSB to slip through the blood brain barrier, and the way in which it shows up on scans.

A spokesman for the Alzheimer's Disease Society said: "There is currently no way to make a definite diagnosis of Alzheimer's disease until the post mortem.

"The current test are all about interpreting scans and symptoms."

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23 Oct 99 | Health
Key Alzheimer's protein found
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