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Research Reports

HEI’s mission is to provide credible science to support environmental regulations and other policy decisions. The results of each HEI-funded project undergo peer-review by outside scientists and the Health Review Committee. The HEI Research Reports contain the Investigator’s Report and the Review Committee’s evaluation of the study, summarized in a Commentary or short Critique.

ISSN 1041-5505 (print)        ISSN 2688-6855 (online) 

Effects of Concentrated Ambient Particles on Normal and Hypersecretory Airways in Rats

Research Report 120
Jack R Harkema
Gerald Keeler
James Wagner
Masako Morishita
Edward Timm
Jon Hotchkiss
Frank Marsik
Timothy Dvonch
Norbert Kaminski
Edward Barr
2004
Topics: 
Particulate Matter

Dr. Jack Harkema and colleagues at Michigan State University conducted a 2-year study with rats to evaluate the short-term effects of inhaling concentrated ambient particles derived from the air in an area of Detroit, Michigan that has a high incidence of childhood asthma. The investigators used two animal models, BN rats that were sensitized with ovalbumin to induce some features of asthma, and F344 rats pretreated with endotoxin to have some features of mild bronchitis. Animals were exposed for 10 hours/day for 1 day or for 4 or 5 consecutive days.

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National Morbidity, Mortality, and Air Pollution Study. Part III: Concentration–Response Curves and Thresholds for the 20 Largest US Cities

Research Report 094-III
Michael J Daniels
Francesca Dominici
Scott L Zeger
Jonathan M Samet
2004
Topics: 
Particulate Matter

In Part III of the National Morbidity, Mortality, and Air Pollution Study (NMMAPS), Dr. Daniels and colleagues at Johns Hopkins University and Harvard University evaluated the shape of the relation between PM10 concentrations measured at fixed monitoring sites and daily mortality among residents from all causes (excluding accidental causes), from all cardiovascular and respiratory causes combined, and from causes other than cardiovascular-respiratory disease.

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Manganese Toxicokinetics at the Blood-Brain Barrier

Research Report 119
Robert A Yokel
Janelle S Crossgrove
2004
Topics: 
Air Pollution
Air Toxics
Emerging Technologies
Fuels & Fuel Additives

Drs. Yokel and Crossgrove at the University of Kentucky Medical Center studied the mechanisms by which manganese enters and leaves the brain across the blood–brain barrier and, in particular, whether transporter molecules are involved. The investigators used in vivo brain perfusion in rats as well as in vitro tests in several cell lines to assess specific characteristics of manganese transport, such as pH and energy dependence. Manganese transport rates were compared with those of sucrose and dextran, which do not easily cross the blood–brain barrier.

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Peroxides and Macrophages in the Toxicity of Fine Particulate Matter in Rats

Research Report 117
Debra L Laskin
Lisa Morio
Kimberly Hooper
Tsung-Hung Li
Brian Buckley
Barbara J Turpin
2003
Topics: 
Particulate Matter

Dr. Laskin and her colleagues at the Environmental and Occupational Health Sciences Institute at Rutgers University tested the hypothesis that oxidants in ambient air, such as hydrogen peroxide, may be transported by fine particulate matter into the lungs and thus contribute to lung tissue injury. The investigators used ammonium sulfate particles because of their prevalence in the ambient air of the eastern United States and their reportedly low toxicity in animals and humans.

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Controlled Exposures of Healthy and Asthmatic Volunteers to Concentrated Ambient Particles in Metropolitan Los Angeles

Research Report 118
Henry Gong Jr
Constantinos Sioutas
William S Linn
2003
Topics: 
Particulate Matter

Dr. Henry Gong Jr and his colleagues at the Los Amigos Research and Education Institute used a Harvard ambient particle concentrator to assess the effects of exposure to concentrated ambient particles (CAPs) on healthy and asthmatic people. 12 healthy individuals and 12 individuals with mild asthma were exposed to either filtered air or CAPs with a maximum exposure level of 200 µg/m3 for two hours while exercising intermittently on a stationary bicycle.

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Health Effects of Acute Exposure to Air Pollution

Research Report 112
Stephen T Holgate
Thomas Sandström
et al.
Stephen T Holgate
Robert B Devlin
et al.
2003
Topics: 
Diesel Exhaust
Particulate Matter
Global Health

Stephen Holgate and his colleagues at the University of Southampton proposed that inflammatory changes in lung fluids and blood from humans exposed to PM were related to the chemical composition of the particles. He obtained samples from two human studies in which participants were exposed to diesel exhaust and concentrated ambient particles (CAPs). At a Swedish laboratory 25 healthy and 12 asthmatic participants were exposed to diesel exhaust or filtered air on separate days. At a US laboratory, 12 healthy participants were exposed to filtered air and 30 different healthy participants were exposed to a range of CAPs concentrations. All participants underwent bronchoscopy to obtain lung tissues and fluids to analyze inflammatory markers, including numbers of specific white blood cells, expression of activation markers, and levels of cytokines in addition to analysis of lung function, lung fluids, and blood.

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