SCIENTISTS have recently confirmed the presence in the lungs of asthmatics of an enzyme that produces nitric oxide, which damages cells lining the airways. Nitric oxide was known to be present in the air exhaled by asthmatics but the enzyme -- nitric oxide synthase -- that triggered its production in the lungs had hitherto not been detected.

A team of researchers from the UK and France, led by Qutayba Hamid, found the enzyme in the lung tissue of 22 of the 23 asthmatics they examined (The Lancet, Vol 342, Nos 8886, 8887).

The researchers suggest that steroids used in the treatment of asthmatics inhibit the production of this enzyme.