The relative importance of air pollution in the pathogenesis of bronchial asthma has been of interest for several decades. Numerous studies on the role of gaseous air pollution containing ozone, nitrogen dioxide, sulfur dioxide, and carbon monoxide have been published. Very little attention has been focused on the role of respirable particles in the causation of asthma. In this article we summarize some of our ongoing investigations into the sources and composition of airborne particles in the Los Angeles and Pasadena atmosphere, including the search for biologically active particles that may induce asthma attacks. If is found that the urban atmosphere contains not only combustion-derived particles from diesel engine exhaust and gasoline-powered motor vehicle exhaust, but also particles formed from biological starting materials including plant debris, cigarette smoke, wood smoke, and meat smoke as well as tire debris containing some natural rubber and paved road dust. Paved road dust is a very complex mixture of particles including garden soil, tire dust, plant fragments, redeposited atmospheric particles of all types, and pollen fragments presumably ground up by passing traffic. We have shown previously that latex allergen can be extracted from tire dust, from roadside dust, and from respirable air samples taken at Los Angeles and Long Beach. At present, work is underway to identify the larger range of allergens that may be contributed by the entrainment of paved road dust into the atmosphere. The possible importance of pollen fragments present in paved road dust in very small particle sizes is discussed as well as their potential relevance in asthma.

Air Pollutants↗

PubMedDate not supplied

Are intravenous corticosteroids required in status asthmaticus?

Seventy-seven patients with status asthmaticus were prospectively studied to compare oral with intravenous methylprednisolone. Patients were given methylprednisolone, either 160 or 320 mg orally or 500 or 1000 mg intravenously, daily in equally divided doses. They were randomly assigned to either group on a daily sequential basis. Spirometry was performed within one hour of the initial dose of steroids. The mean presenting forced expiratory volume in 1 s was 26% of the predicted value. Spirometry was then repeated every six hours for the first 24 hours and then every eight to 12 hours until discharge or 72 hours, whichever occurred first. There were no significant differences in the incidence of respiratory failure, forced expiratory volume in 1 s, days of hospitalization, rate of improvement in pulmonary function, or side effects. No patient who went into respiratory failure did so more than three hours after receiving the initial dose of steroids. We conclude that oral methylprednisolone is safe and effective in the treatment of status asthmaticus.

Administration, Oral↗