THE VIRGINIAN-PILOT
Copyright (c) 1995, Landmark Communications, Inc.
DATE: Monday, October 30, 1995 TAG: 9510300074
SECTION: FRONT PAGE: A10 EDITION: FINAL
SOURCE: ASSOCIATED PRESS
DATELINE: BALTIMORE LENGTH: Short : 48 lines
Asthmatics wheeze because their lung muscles can't relax, not because of irritants in the air, a new study suggests.
``If that is the case, then we can probably detect it very early on, before people develop asthma,'' said Dr. Alkis Togias of Johns Hopkins Medical Center, who presents the findings in the November issue of The Journal of Clinical Investigation.
In an asthma attack, the smooth muscles that line the lungs contract, blocking the passage of air and leaving victims gasping for breath.
Scientists have thought the muscles contract because of an unusual reaction to irritants or allergens, such as airborne pollen or pollutants.
Togias and a team of Hopkins researchers believe asthmatics and non-asthmatics alike have the same air-blocking reaction to lung irritation.
But they contend asthmatics have a second problem: lung muscles that cannot relax normally.
``We suspect that non-asthmatics overcome this reaction by using deep breaths to relax the muscles and open up the air passages and that asthmatics lack this ability,'' Togias said.
``It is definitely not the conventional wisdom,'' said Dr. Michael Kaliner, medical director of the Institute for Asthma and Allergy at the Washington Hospital Center, who had not seen the study.
``There is some data to support that. When you and I take a deep breath, our muscles stay relaxed. But when an asthmatic takes a deep breath the muscles do contract. Whether that is important or not, I honestly don't know.''
The researchers tested their theory by making non-asthmatics wheeze as asthmatics do. The researchers gave non-asthmatics the inhalant drug methacholine, which acts as an irritant and causes breathing problems in asthmatics. Then they told the volunteers not to breathe deeply.
The result: Non-asthmatics developed asthma-like breathing problems.
``This is just the reaction we would expect if asthma is caused by an impairment of muscle relaxation triggered by deep breaths,'' Togias said.
KEYWORDS: ASTHMA ALLERGY STUDY by CNB