Cotton Bract and Human Airway Hyperresponsiveness

摘要

Nonspecific airway response to methacholine (MC) following inhalation of cotton bract extract (CBE) was investigated in 13 volunteers. Five of these 13 demonstrated a ventilatory response to CBE with a 20 percent or larger decrement in the maximal expiratory flow. No such changes were noted on exposure to a normal saline aerosol sham exposure. The peak decrease was 76.5 percent of baseline occurring about 60 to 90 minutes post-provocation while the peak decrement following normal saline occurred immediately on inhalation. Mild and transient changes in airway responsiveness to MC were noted. While the findings do not appear to have enormous clinical significance in the case of healthy volunteers, the fact that there was an acute and mild airway hyperresponsiveness to CBE suggested that under conditions of repeated exposure to cotton dust, progressive increases in airway hyperresponsiveness leading to chronic airflow obstruction is possible. In the case of byssinosis, a period of time apparently exists where the acute reversible changes in lung function transform to a chronic and disabling airflow obstruction.