INTRODUCTION TO THE POSTER

photo of GAGE

This work was performed at THE GAGE OCCUPATIONAL AND ENVIRONMENTAL HEALTH UNIT of the UNIVERSITY OF TORONTO, 223 College Street, Toronto Canada (416) 978-5883 (entrance off Ross St. shown above) The GOEHU is a department of St. Michael's Hospital Toronto. The work to be described had the approval of the ethics committee at St. Michael's Hospital, University of Toronto. The work was funded by the Toxic Substances Research Initiative (TSRI) which was a program initiated by the Federal Government of Canada to solicit research into substances toxic to humans in the environment. GO TO TSRI

We have hypothesised that children who have on-going eosinophilic inflammation in their airways will show an increase in that inflammation after exposure to ground-level Ozone. Go To Background Information

In order to test that hypothesis we have recruited children with asthma who are not being treated with inhaled steroid but are allergic to a pet in their home. We have previously shown that such children can have high levels aof eosinophils in their airways (as measured by the echnique of induced sputum) despite having only intermittent symptoms. Their asthma symptoms do not reflect the degree of inflammation in their airways and as a result the pet is not eliminated from the home and the children are not treated with regular inhaled steroid. These children represent a model for the common scenario of undertreatment of childhood asthma.

We have also recruited children with asthma who are being treated with inhaled steroid continuously in order to test the hypothesis that inhaled steroid will prevent any changes observed when untreated asthmatic children are exposed to Ozone. We are also studying children without asthma or allergy as "normal" controls.

The Gage houses various chambers for the experimental exposure to Ozone or other environmental substances such as particle.
chamber for challenge The children are exposed to controlled levels of ozone in the chamber shown at left. They are carefully monitored and spend two hours in the chamber in either filtered air or ozone, equivalent to a smoggy day in Los Angeles. They pedal a bicycle for 15 minutes, twice per hour to increase their breathing rate.


The children are studied using the techniques of spirometry, methacholine challenge, induced sputum and nasal lavage.
induced sputum Inflammation in the airways is assessed using the technique of induced sputum. Children inhale nebulized salt water for periods of time and then are encouraged to cough sputum samples into a container. The samples are prepared and spun on to a slide then stained and examined under the microscope.