Christopher J. Portier

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Daily measures of maximum temperature, particulate matter less than or equal to 10 micro m in aerodynamic diameter (PM10), and gaseous pollution (ozone, nitrogen dioxide, sulfur dioxide, and carbon monoxide) were collected in Denver, Colorado, in July and August between 1993 and 1997. We then compared these exposures with concurrent data on the number of(More)
BACKGROUND Benzene, an established cause of acute myeloid leukemia (AML), may also cause one or more lymphoid malignancies in humans. Previously, we identified genes and pathways associated with exposure to high (> 10 ppm) levels of benzene through transcriptomic analyses of blood cells from a small number of occupationally exposed workers. OBJECTIVES The(More)
Under a mandate from the U.S. Congress, the National Toxicology Program (NTP) of the U.S. Department of Health and Human Services conducts animal bioassays for carcinogenicity of potentially toxic chemicals to which the U.S. population might be exposed. Methyleugenol, a natural as well as synthesized substance, was nominated for study because it is(More)
BACKGROUND The propensity of compounds to produce adverse health effects in humans is generally evaluated using animal-based test methods. Such methods can be relatively expensive, low-throughput, and associated with pain suffered by the treated animals. In addition, differences in species biology may confound extrapolation to human health effects. (More)
BACKGROUND Biomonitoring data reported in the National Report on Human Exposure to Environmental Chemicals [NER; Centers for Disease Control and Prevention (2012)] provide information on the presence and concentrations of > 400 chemicals in human blood and urine. Biomonitoring Equivalents (BEs) and other risk assessment-based values now allow interpretation(More)
Population-based estimates of environmental exposures using biomarkers can be difficult to obtain for a variety of reasons, including problems with limits of detection, undersampling of key strata, time between exposure and sampling, variation across individuals, variation within individuals, and the ability to find and interpret a given biomarker. In this(More)
BACKGROUND The nematode Caenorhabditis elegans is being assessed as an alternative model organism as part of an interagency effort to develop better means to test potentially toxic substances. As part of this effort, assays that use the COPAS Biosort flow sorting technology to record optical measurements (time of flight (TOF) and extinction (EXT)) of(More)
There is increasing evidence that receptor-mediated events impact one or more stages responsible for tumor development in experimental animals and humans. Although many chemicals and endogenous hormones require receptor interactions as a necessary event in their carcinogenic activity, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and its structural analogs are(More)
BACKGROUND The proneural proteins Mash1 and Ngn2 are key cell autonomous regulators of neurogenesis in the mammalian central nervous system, yet little is known about the molecular pathways regulated by these transcription factors. RESULTS Here we identify the downstream effectors of proneural genes in the telencephalon using a genomic approach to analyze(More)