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Wednesday, 10 May, 2000, 23:52 GMT 00:52 UK
Secrets of hearing uncovered
hearing test
The discovery could eventually lead to treatments
Scientists believe they have unlocked the biological secrets of a cell which plays a key role in human hearing.

The cell protein they have identified could have a host of applications even in other parts of the body.

It's a very significant piece of work

Dr Matthew Holley, Bristol University
What researchers at Northwestern University in the US have found is a chemical which facilitates a dramatic and swift change of shape in the "hair cells".

It is these which help "amplify" the sounds travelling into the ear so they can be passed on to the brain.

It is thought understanding the way these cells work may help develop therapies for tinnitus, a permanent ringing in the ears which affects thousands in the UK.

Inherited deafness

It is possible some forms of hereditary deafness could be linked to the protein.

But the unique ability of the cell to turn electrical impulses into powerful movements means the cells could have other uses.

In theory, one day, scientists might be able to create tiny biological pumps using them.

Human hearing is extraordinarily sensitive compared to that of many other mammals, with the cells able to operate at frequencies between approximately 20 to 20,000 movements a second.

Tinnitus can be caused by repeated exposure to loud noises, such as explosions, which can damage or destroy the "hair cells".

Unlike some other cells, a human has only a fixed number of hair cells, and they do not reproduce if any are destroyed.

Unlike other reactions in the body in which electrical signals are converted into cell shape changes, such as those which happen in the muscles, this reaction does not need a supply of extra biological energy to work.

Scientists are hopeful this means the cells could be used in nanotechnology.

'It's a breakthrough'

Laurence Marks, professor of materials science at Northwestern University, said: "One can envisage creating hybrid structures using this protein in artificial membranes that are part of nano electro-mechanical systems, for instance biological pumps that might be used for drug delivery."

Dr Matthew Holley, a Fellow of the Royal Society whose work centres on the genetic make-up of the inner ear, confirmed that the discovery of the protein was a breakthrough.

He said: "It's a very significant piece of work.

"We believe that in tinnitus, this 'amplifier' going wrong is at least partly to blame, although there are probably other factors.

"But the speed at which the cell changes shape means there could well be other uses."

The research was reported in the journal Nature.

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See also:

03 Aug 99 | Health
Loud music threat to the young
19 Nov 99 | Health
New hearing test unveiled
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