Determined the half maximal response to acute OVA exposure in terms of airway hyperresponsiveness and total inflammatory cells bronchoalveolar lavage for wild type mice. This level of OVA exposure will be used in combination with ultrafine particle exposure to determine whether ultrafine particles can exacerbate the OVA response. Based on discussions with other investigators and our own investigations we have found that the generator being used to produce 99.99 percent pure inorganic carbon particles is actually producing particles with a 60-70 percent organic carbon fraction. Initial characterization of these particles shows the organic fraction to be comprised of materials from plastics. Plastic components within the generator and plastic tubing are the main suspects for the organic carbon fraction.
Work is underway to identify and eliminate potential contaminating.
Set up, test and calibrate new Buxco Electronics whole-body exposure system that will allow for the measurement of airway responsiveness in unrestrained and unanesthetized animals. Characterization of particle concentration and size distribution within the mouse colony room and within an individual mouse cage to determine background particle exposure levels. Evaluations Made During the Reporting Period Our progress this year has been centered on developing and characterizing a new animal exposure model. The model is also suited to test the hypothesis that an elevated background level of inflammation in the lung is required for inhaled ultrafine particles to exacerbate allergic asthma. None at this time.