This study will determine if exposure to an allergy material (ragweed) or exposure to an
allergic-symptom-provoking substance (histamine) and medications typically used to decongest
the nose changes the rate of blood-flow in the lining of the middle-ear. Otitis media (the
build-up of water-like fluid in the middle-ear airspace) may occur if the blood flow in the
lining of the middle-ear is too high and may be prevented if a way could be found to lower
the blood flow in persons susceptible to the disease. Middle-ear blood flow is measured
indirectly by measuring the change in middle-ear pressure while a person breathes a gas
mixture containing nitrous oxide ("laughing gas"). In this study, 4 groups of subjects will
be entered and middle-ear pressure in persons breathing a mixture of 50% Oxygen, 50% Nitrous
Oxide ("laughing gas")will be measured after exposure to one of four substances (ragweed,
histamine,an oral decongestant, a decongestant nasal spray) and a fake medication (placebo)
at separate test sessions. All subjects will have one set of 2 x-rays of the middle ears and
mastoids. The group exposed to ragweed will require 3 study visits while the other 3 groups
will have 2 study visits. From this information middle-ear blood flow will be calculated.
This will help determine the relationship between what happens in the nose and what happens
in the middle ear.
Phase:
Phase 1
Details
Lead Sponsor:
Cuneyt M. Alper University of Pittsburgh
Collaborator:
National Institute on Deafness and Other Communication Disorders (NIDCD)