Publications

This report describes a study by Drs. Yu and Yoon to mathematically predict the lung burden in rats and humans of diesel exhaust particles (DEP) from automobile emissions. Building on a previously constructed model describing DEP deposition, the present work focused on clearance and retention of DEPs deposited in the lung. The transport rates of each component of DEPs were derived using experimental data and mathematical approximations. The complete model was first developed for rats and then extrapolated to humans of different age groups.

This report describes a study by Drs. Ultman and Ben-Jebria to develop a chemiluminescent ozone analyzer and constructed an ozone bolus generator with the goal of using bolus concentration-response methods to noninvasively measure the longitudinal distribution of ozone absorption in human lungs. The analyzer was based on the chemiluminescent reaction between 2-methyl-2-butene and ozone. Validation of the system was performed in excised pig and sheep tracheas, and the resulting absorption coefficient was computed.

This report describes a study by Dr. Last to investigate possible synergistic effects of multiple air pollutants on pulmonary measures in rats. Rats were exposed for 1-9 days to mixtures of O₃ or NO₂ and aerosols of sulfuric acid, ammonium sulfate, or sodium chloride, and to each pollutant individually. Responses were evaluated by various biochemical and morphometric analyses of lung tissue and lavage fluid. An additional preliminary experiment treated exposed rats in vivo with various free-radical scavengers to elucidate possible protective properties.

This report describes a study by Dr. Johnson and colleagues to test the hypothesis that inhaled oxidants can cause lung damage by inactivating the proteinase inhibitors that normally protect the lung from proteolysis. In the first set of experiments, the functional activity of rat alpha-1-proteinase inhibitor (á1-PI) was measured in rat lung lavage fluid from rats exposed acutely or chronically to varying concentrations of NO₂, diesel exhaust, O₃, and O₃ in conjunction with CO₂.

This report describes a study by Dr. Verrier and colleagues to explore the effects of acute carbon monoxide (CO) exposure on cardiac electrical stability through a number of biological models. Experiments involved cardiac electrical testing of conscious and anesthetized dogs with normal and ischemic hearts who were exposed to CO for 2 or 24 hours. The experimental plan explored both the direct effects of CO exposure on the myocardium and possible indirect effects through alterations in the ability of platelets to aggregate or changes in nervous system activity.

This report describes a study by Dr. Moon and colleagues to investigate the carcinogenic potential of 1-nitropyrene, a mutagenic constituent of diesel exhaust particles, using a hamster respiratory-carcinogenesis model. Male hamsters were exposed to 1 or 2 mg of 1-nitropyrene via intratracheal administration either once or twice a week for 92 weeks. In order to study activity as a cocarcinogen, 1 or 2 mg of 1-nitropyrene was administered in combination with 0.25 mg of the known environmental carcinogen benzo[α]pyrene once per week for 92 weeks.

This report from the HEI Multicenter CO Study examined the effect of carbon monoxide (CO) exposure of male human participants with coronary artery disease, with a particular focus on myocardial ischemia onset during exercise. The participants were exposed to air or to CO concentrations sufficient to elevate blood carboxyhemoglobin (COHb) levels to 2% or 4% during exercise. The primary health endpoints examined were the time to onset of exercise-induced angina, and the time to a predefined ST-segment change.

This report describes two pilot investigations for a longitudinal study of infants designed to determine if NO₂ exposure from cooking stoves increases the incidence or severity of respiratory infections during the first 18 months of life. In the first study, Drs. Samet and Spengler selected 147 households with electric or gas stoves and infants for home indoor monitoring of NO₂ concentrations; the infants\' mothers completed a daily calendar-diary on respiratory symptoms and provided illness information every 2 weeks.

This report describes a study by Dr. McGrath to investigate the effect of chronic exposure of rats to CO at high altitude. Male rats were exposed for 6 weeks to CO ranging from 0 to 500 ppm at simulated altitudes ranging from 3,300 to 18,000 feet. The following weekly measurements were taken throughout the exposure period: weight, hematocrit, hemoglobin, and carboxyhemoglobin concentrations. Arterial pH, partial pressure of CO in the blood (PCO₂) and PO₂ were measured, as were blood pressure and ECG.

This report examined the effect of nitrogen dioxide exposure on the sensitivity of the lower respiratory tract to viral infection and reinfection. Dr. Rose and colleagues exposed mice to concentrations of nitrogen dioxide ranging from 1-10 ppm or to air prior to and after inoculation with varying doses of murine cytomegalovirus. A subset of mice was reinfected 30 days later. Infection status, macrophage phagocytic uptake, lymphocyte function, and virus-specific antibody levels were measured, and the results were compared by exposure condition.

This report investigated changes in pulmonary function, as well as the occurrence of symptoms, in potentially susceptible human subpopulations exposed to nitrogen dioxide. Drs. Morrow and Utell exposed healthy individuals and individuals with asthma, chronic obstructive pulmonary disease, and acute respiratory infection to air or 0.3 ppm nitrogen dioxide. The exposure period (four hours per day for five consecutive days) included defined periods of moderate exercise and pulmonary function measurements including spirometry, airway conductance, airway reactivity, and symptoms.

This report investigated the influence of acute exposure to nitrogen dioxide on susceptibility to and severity of viral and bacterial infection in mice. Dr. Jakab exposed normal and immunosuppressed mice to concentrations of nitrogen dioxide ranging from 1 to 30 ppm before or after bacterial or viral challenge and measured host resistance to infection by physiologic parameters.