Papers by Roger McClellan
The mutagenicity of organic solvent extracts from diesel exhaust particulate (DEP), first noted m... more The mutagenicity of organic solvent extracts from diesel exhaust particulate (DEP), first noted more than 55 years ago, initiated an avalanche of diesel exhaust (DE) health effects research that now totals more than 6000 published studies. Despite an extensive body of results, scientific debate continues regarding the nature of the lung cancer risk posed by inhalation of occupational and environmental DE, with much of the debate focused on DEP. Decades of scientific scrutiny and increasingly stringent regulation have resulted in major advances in diesel engine technologies. The changed particulate matter (PM) emissions in “New Technology Diesel Exhaust (NTDE)” from today’s modern low-emission, advanced-technology on-road heavy-duty diesel engines now resemble the PM emissions in contemporary gasoline engine exhaust (GEE) and compressed natural gas engine exhaust more than those in the “traditional diesel exhaust ” (TDE) characteristic of older diesel engines. Even with the continued...
Increasing numbers of automobiles and light-duty trucks are likely to be equipped with diesel eng... more Increasing numbers of automobiles and light-duty trucks are likely to be equipped with diesel engines in the future because they have higher fuel efficiencies than gasoline engines and because diesel fuel traditionally has cost less than gasoline. Interest in diesel engines also was stimulated by the Federal Corporate Average Fuel Economy Requirement for 1985 (7). By then, manufacturers of light-duty vehicles must attain an overall fleet average of 27.5 miles per gallon (mpg) (11.7 km/L) of fuel. Introducing more fuel-efficient diesel-powered vehicles is one approach to meeting the fuel economy average while minimizing the need to reduce vehicle size. Current diesel-powered vehicles emit more visible smoke and odors than gasoline-powered vehicles, and this has led to concern about their possible effects on human health and the environment. In November 1977, the EPA issued a precautionary notice reporting that organic solvent extracts of diesel exhaust particles were mutagenic in bac...
Fission product inhalation project [technical progress report]. Lovelace Foundation for Medical Education and Research, 1969
Concepts In Inhalation Toxicology, 1995
... Bernard Greenspan, John Morris, Sidney Soderholm, David Velasquez, John Ballou, Bruce Lehnert... more ... Bernard Greenspan, John Morris, Sidney Soderholm, David Velasquez, John Ballou, Bruce Lehnert, Bart Dahneke, Justin Postendorfer, Werner ... at, for example, Kettering Laboratory, General Motors, University of Pittsburgh, Harvard School of Public Health, Lovelace ITRI, New ...
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Radiation Research, 1992
Twenty male cynomolgus monkeys were exposed by inhalation either to an aerosol of 239Pu(NO3)4 to ... more Twenty male cynomolgus monkeys were exposed by inhalation either to an aerosol of 239Pu(NO3)4 to produce projected initial lung burdens of either 40, 10, or 4 kBq or to a carrier aerosol as a control. Animals died or were sacrificed at 0.01, 1, 3, 6, 12, 24, 40, and 99 months after inhalation, and the distribution and biological effects of the 239Pu were determined. The 239Pu cleared efficiently from the lungs so that less than 0.05 kBq remained at 99 months after exposure to 40 kBq. Total skeletal 239Pu activity was nearly constant after the first year, but the fraction of the body burden in skeleton at sacrifice increased with time up to 99 months because of clearance from other organs. Plutonium in the liver increased to a peak at 1 year and then decreased to about 10% of the peak value at 99 months. Plutonium in the testes was localized in the interstitial tissue with only 0.01 to 0.002% of the projected lung burden remaining in testes at 99 months after inhalation. Three animals exposed to 40 kBq of 239Pu died of radiation-related pulmonary pneumonitis and fibrosis. A primary papillary adenocarcinoma of the lung was identified in one animal exposed to 40 kBq initial lung burden and sacrificed 99 months after inhalation. The frequency of chromosome aberrations in blood lymphocytes was significantly elevated only in monkeys with projected deposits of 40 kBq of 239Pu. There was no change in aberration frequency in other exposure groups as a function of inhaled activity, time after exposure, or calculated total dose to the lungs. Only in monkeys that had marked radiation-induced pathological changes in the lung did the frequency of chromosome-type aberrations increase significantly, to a value about twice the control level. In cynomolgus monkeys, chromosome aberration frequency in blood lymphocytes is not a good indicator of radiation dose or damage from inhaled soluble plutonium.
Radiation Research, 1987
To determine the long-term biological effects of protracted alpha irradiation of the lung, 84-day... more To determine the long-term biological effects of protracted alpha irradiation of the lung, 84-day-old C57BL/6J mice were repeatedly exposed by inhalation to aerosols of 239PuO2 every other month for up to six exposures in 10 months to reestablish lung burdens of 20, 90, or 460 Bq. Other mice were exposed only once when either 84 or 460 days of age to achieve desired initial lung burdens of 20, 90, 460, or 2300 Bq. Suitable control groups were maintained. Groups of mice with similar cumulative alpha doses to the lung had 3.4 to 4.4 times greater incidence of pulmonary tumors (adenomas and adenocarcinomas) when the dose to the lung was protracted by the repeated inhalation exposures compared to mice that received a single inhalation exposure. Excess pulmonary tumors per unit dose to the lung were also greater in groups of repeatedly exposed mice compared to those exposed only once. Repeatedly exposed mice also died earlier with pulmonary tumors than did those exposed once. It appears that protraction of an alpha dose to lungs increases the carcinogenic risk of inhaled 239PuO2 in mice.
Clinics in Occupational and Environmental Medicine, 2003
Journal of Aerosol Science, 1981
Deposition and retention of ultrafine chain aggregate particles were studied in 20 beagle dogs. A... more Deposition and retention of ultrafine chain aggregate particles were studied in 20 beagle dogs. Aggregated particles of insoluble °7Ga203 in the 0.1 pm size range were generated by heat treatment of 6'Ga tetramethylheptanedione. Size characterization was done using electron microscopy, diffusion battery and electrical aerosol analyzer measurements. The average equivalent diffusion diameter of the aerosol was 0.07 pm and the volume median diameter [electrical mobility measurement} was 0.10 gm with a geometric standard deviation of 1.6. Primary particles from which the aggregates were formed were 0.01-0.02 #m in diameter. Whole-body counting and gamma camera imaging were used to measure deposition. Total deposition in the whole body was 33 + 16 % (mean _+ S.D.) of the inhaled particles; 82 _ 13 % of this material was deposited in the lung. Retention studies showed that 77 + 30o of the material deposited in the lung was in the pulmonary region. Thus, 21% of the inhaled particles were deposited beyond ciliated airways in alveolar areas. The deposition in the deep lung has important implications for health risk assessments of particles in the environment of similar size and shape such as diesel exhaust emissions.
Encyclopedia of Sustainability Science and Technology, 2012
Convert to machine form, etc. Identify needs for expertise Find and recruit experts Organize join... more Convert to machine form, etc. Identify needs for expertise Find and recruit experts Organize joint efforts, within constraints
Toxicological Sciences, 2003
Concepts In Inhalation Toxicology, 1995
ABSTRACT-Primary bone neoplasms developed in beagle dogs briefly exposed by inhalation to aerosol... more ABSTRACT-Primary bone neoplasms developed in beagle dogs briefly exposed by inhalation to aerosols of 238PU02 ' 238PU02 was initially deposited in the respiratory tract where it was retained with a half time greater than 100 days. A portion of the 238PU was solubilized and translocated to the liver and skeleton. Five years after exposure. 46 osteosarcomas developed in 35 of 144 ex-posed dogs. The cumulative absorbed radiation doses to skeleton for these dogs ranged from 210 to 830 rad. Of the 46 bone tumors. 22 originated in the vertebrae. 12 in the humeri. 6 in the pelves. and 6 in miscellaneous long and flat bones. Most of the tumors were well-differentiated sarcomas. Only 10 of the tumors metastasized; the lung was the organ most often invaded. Bone tumors were associated with lesions of radiation osteodysplasia. The number of bone tumors found in this study indicated that inhaled 23SPU02 was an effective skeletal carcinogen. The rate of
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Papers by Roger McClellan