Increase in gastroesophageal reflux during methacholine-induced bronchospasm.

There is an increased incidence in gastroesophageal reflux (GER) in subjects with asthma. The cause-effect relationship remains controversial. We compared 15 subjects with mild asthma to 15 control subjects (nonasthmatic) to ascertain if GER might be induced by bronchospasm.

Opposite changes in blood histamine and force expiratory volume during bronchial inhalation challenge.

Lack of in vivo data on blood histamine changes in subjects during induced attacks of asthma prompted serial determinations of blood histamine levels and of the forced expiratory volume of the first second (FEV1) in 2 asthmatic undergoing antigen (house dust) inhalation challenge and in 3 subjected to methacholine inhalation. In 1 of 2 dust-sensitive asthmatics inhaling house dust (10(4) pnu), a prominent histamine spike occurred 5 minutes after challenge termination, coinciding with a fall in FEV1 by about 15%. In the other, blood histamine had risen steeply at 7 minutes, FEV1 not falling, due presumably to increased bronchial tolerance acquired by hyposensitization therapy.