Environews
NIEHS NEWS | Space-Based Health
Imagine being able to improve human health based on satellite data gathered from space. This concept, as futuristic as it might sound, is actually one that experts see as potentially viable and beneficial. This month's article (p. A738) describes a workshop cosponsored by the NIEHS and the U.S. Environmental Protection Agency that united Earth and health scientists to discuss possibilities for translating satellite data into a concrete tool for both environmental health research and public health policy.
FOCUS | Nuclear Redux
Our relationship with nuclear energy hasn't exactly been an easy or completely comfortable one, but we're obliged to acknowledge the technology's usefulness. Now, after some costly and cautionary setbacks in past decades, nuclear energy is slowly reclaiming interest as a reliable source of electricity. This article (p. A742) examines how we've dealt with nuclear power in the past, looks at some of the benefits and risks associated with its use, and discusses how it might fit into the future of global power generation.
SPHERES OF INFLUENCE | Biomass Boom?
With gas prices continually on the rise, the search for alternative sources of fuel has steadily heated up as well. One potentially promising source is biomass energy--fuel from plant-derived molecules. This article (p. A750) examines a federally funded report that recommends moving beyond our current levels of biomass use to lessen our dependence on fossil fuels. Can we efficiently increase our use of nature's other bounty while having a minimal impact on the environment?
INNOVATIONS | Microbial Fuel Cells
As our population continues to expand, we are faced with the dilemmas of ever-growing energy demands and mounting waste disposal concerns. Today researchers are fighting back by developing processes that put waste to use as an energy source. This article (p. A754) looks at the use of microbial fuel cells, which, once perfected, could harvest energy from household organic waste to generate electricity.
Commentary
POPULATION HEALTH | HYENA Study Design and Noise Exposure Assessment
Jarup et al. (p. 1473) introduce the Hypertension and Exposure to Noise near Airports (HYENA) project, which aims to assess the impact of airport-related noise exposure on blood pressure and cardiovascular disease using a cross-sectional study design. The study involves 6,000 persons (45-70 years of age) living near one of six major European airports for at least 5 years. The project also assesses exposure to traffic-related air pollutants, primarily using data from another project funded by the European Union (APMoSPHERE).
Review
GENE POLYMORPHISM | Genetic Factors and Perchlorate
Perchlorate contamination may be more widespread than previously thought. Perchlorate is a competitive inhibitor of the sodium iodide symporter, the thyroid cell-surface protein responsible for transporting iodide from the plasma into the thyroid. Scinicariello et al. (p. 1479) review genetic biomarkers that would help define subpopulations sensitive to perchlorate exposure: defects in iodide transport into the thyroid cell, defects in iodide transport from the thyroid cell to the follicular lumen (Pendred syndrome), and defects of iodide organification. Future studies linking human disease and environmental perchlorate exposure should consider the genetic makeup of the participants, actual perchlorate exposure levels, and individual iodine intake/excretion levels.
Research
RESPIRATORY DISEASE | Ultrafine Particle Exposure and Oxidative DNA Damage
Ultrafine particles (UFPs) from vehicle exhaust are related to cardiovascular and pulmonary disease and cancer. Vinzents et al. (p. 1485) used portable instruments in healthy nonsmoking subjects to study personal exposure as the concentration of UFPs in the breathing zone. Oxidative DNA damage was assessed as strand breaks and oxidized purines in mononuclear cells isolated from blood the morning after exposure measurement. Cumulated outdoor and indoor exposures to UFPs each were independent significant predictors of the level of purine oxidation in DNA but not of strand breaks. Biologic effects of UFPs occur at modest exposure, which supports the relationship between UFPs and adverse health effects.
TOXICOLOGY | Brevetoxin Associated with High-Density Lipoprotein
Woofter et al. (p. 1491) investigated the distribution of brevetoxin PbTx-3 among carrier proteins. In both in vitro and in vivo experiments, the majority of brevetoxin immunoreactivity was restricted to gradient fractions that contained high-density lipoproteins (HDLs). This information on the association of brevetoxins with HDLs provides a new foundation for understanding the process by which the toxin is delivered to and removed from tissues and may permit more effective therapeutic measures to treat intoxication from brevetoxins and the related ciguatoxins.
ENVIRONMENTAL TOXICOLOGY | Risk of Amphibian Limb Malformation
The cause of limb deformities in wild amphibian populations remains unclear. Taylor et al. (p. 1497) assessed independent risk factors for nontraumatic limb malformation in a cross-sectional survey of hylid and ranid metamorphs in Vermont wetlands. In a multiple logistic regression model that included land use, developmental stage, genus, and water-quality measures, proximity to agricultural land use was associated with an increased risk of limb malformation. These findings support the role of chemical toxicants in limb malformation and demonstrate the value of an epidemiologic approach to this problem.
POPULATION HEALTH | Framing Scientific Analyses for Risk Management
Risk management provides a context for addressing environmental health hazards. Critical to this approach is the identification of key opportunities for participation, and thus two-way communication. Judd et al. (p. 1502) present case studies of three groups--an Asian and Pacific Islander community coalition and two Native American Tribes--who are active in framing scientific analyses of health risks related to contaminated seafood. These examples present a spectrum of options for increasing community involvement in framing analyses and also highlight the need for increased support of such activities.
GENE POLYMORPHISM | Uric Acid and Gene Polymorphisms in Lead Workers
Weaver et al. (p. 1509) analyzed uric acid and lead levels together with data on three genetic polymorphisms associated with renal outcomes--
-aminolevulinic acid dehydratase (ALAD), endothelial nitric oxide synthase (eNOS), and vitamin D receptor (VDR)--among current and former lead workers. Participants with the eNOSAsp allele had lower mean serum uric acid compared with those with the Glu/Glu genotype. Among older workers, higher lead dose was associated with higher uric acid in workers with the ALAD1-1 genotype; associations were in the opposite direction in participants with the variant ALAD1-2 genotype. Higher tibia lead was associated with higher uric acid for the variant VDRB allele. Results indicate that genetic polymorphisms may modify uric acid mediation of lead-related adverse renal effects.
RESPIRATORY DISEASE | Within- and Between-Home Variation in House Dust Endotoxin
Endotoxin exposure may be a determinant of allergen responses in children. To better understand the implications of using a single measurement of house dust endotoxin to characterize exposure in the first year of life, Abraham et al. (p. 1516) evaluated room-specific within-home and between-home variability in dust endotoxin. Levels were highest during summer and lowest in the winter. Mean endotoxin levels varied significantly from room to room. Adjusting for season, within-home variation was less than between-home variation for kitchen, bedroom, and family room. Results indicate that room-to-room and home-to-home differences influence the total endotoxin variability more than factors affecting levels within a room over time.
ENVIRONMENTAL TOXICOLOGY | Environmental Contaminants and Histamine Receptors
Heavy metals and pesticides alter behavioral and neuroendocrine functions of many aquatic organisms. Giusi et al. (p. 1522) show that cadmium and the pesticide endosulfan cause neuronal degeneration in mesencephalon and hypothalamus correlated with altered binding levels of the three major histamine receptors (subtypes 1, 2, and 3) in the teleost ornate wrasse (Thalassoma pavo). Although cadmium accounted for reduced binding activity of all three subtypes in most brain regions, subtype 2 appeared to be the main target. Conversely, endosulfan up-regulated levels of subtypes 3 and 1 in preoptic-hypothalamic areas.
EXPOSURE ASSESSMENT | Predictors of Urinary Phthalate Levels
Phthalates are used in personal care products. Duty et al. (p. 1530) explored the relationship between the use of personal care products and levels of several urinary phthalate metabolites in men who participated in an ongoing semen quality study at the Massachusetts General Hospital. Men who used cologne or aftershave within 48 hr before urine collection had higher median levels of monoethyl phthalate (MEP) (265 and 266 ng/mL, respectively) than those who did not use cologne or aftershave (108 and 133 ng/mL, respectively). For each additional type of product used, MEP increased 33%. The identification of personal care products as contributors to phthalate body burden is an important step in exposure characterization.
CARDIOVASCULAR DISEASE | Particle Exposure and Inflammation
Macrophages play a key role in atherogenesis by releasing proinflammatory cytokines and forming foam cells in subendothelial lesions. Vogel et al. (p. 1536) quantified the inflammatory response in a human macrophage cell line (U937) after exposure to an urban dust particulate (UDP) sample and a diesel exhaust particulate (DEP). The authors compared the effect of UDP and DEP with their corresponding organic extracts and stripped particles. The particles and the organic extract-induced expression of cyclooxygenase-2 and cytochrome P4501a1 was significantly suppressed by co-treatment with an aryl hydrocarbon receptor antagonist. The data illustrate interaction between particulate matter and inflammatory response as well as formation of cholesterol-accumulating foam cells, which are early markers of cardiovascular disease.
NEUROBEHAVIORAL DISEASE | Volatile Organics, Ozone, and Stress
Fiedler et al. (p. 1542) tested the health effects of controlled exposures to volatile organic compounds (VOCs) and psychological stress, with and without ozone, in women. Mixing VOCs with O3 produced aldehydes, hydrogen peroxide, organic acids, secondary organic aerosols, and ultrafine particles. Exposure to VOCs with and without O3 did not result in significant health effects. Psychological stress significantly increased salivary cortisol and symptoms of anxiety regardless of exposure condition. Neither lung function nor neurobehavioral performance was compromised by exposure to VOCs or VOCs plus O3. Stress appears to be a more significant factor than chemical exposures in affecting some health end points.
Also see Science Selections, p. A760
RISK CHARACTERIZATION | Cumulative Risk of Thyroid Disruptors
Crofton et al. (p. 1549) tested the hypothesis that a mixture of thyroid-disrupting chemicals (TDCs) will affect serum total thyroxine (T4) concentrations in a dose-additive manner. Extensive dose-response functions were determined in young female rats for T4 and exposure to 18 individual chemicals. A mixture was synthesized based on environmental concentrations, and serial dilutions of this mixture ranged from background to 100-fold greater than background human daily intakes. The authors found no deviation from additivity at the lowest doses, but there was a greater-than-additive effect at the three highest doses. At high doses the additivity model underpredicted the empirical effects by 2- to 3-fold.
Also see Science Selections, p. A758
TOXICOLOGY | Ultrafine Particle Distribution in Lungs
Airborne particles are associated with increased pulmonary and cardiovascular mortality, with indications of a specific toxicologic role for ultrafine particles (UFPs; particles < 0.1 µm). Geiser et al. (p. 1555) combined in vivo experiments in rats with in vitro approaches using macrophages and red blood cells to study the distribution of UFPs in the lung and their uptake by cells. Inhaled UFPs were found on the luminal side of airways and alveoli, in all major lung tissue compartments and cells, and within capillaries. Particle uptake in vitro into cells occurred by diffusion or adhesive interactions. Particles within cells are not membrane bound and have access to intracellular proteins, organelles, and DNA.
Also see Science Selections, p. A758
TOXICOLOGY | Pulmonary and Systemic Effects of Ambient Particles
Several studies report health effects of concentrated ambient particles (CAPs) in rodents and humans. However, toxicity end points in rodents have been inconsistent. Kodavanti et al. (p. 1561) conducted 1- and 2-day exposure studies using spontaneously hypertensive rats and/or Wistar Kyoto rats exposed to filtered air or CAPs for 4 hr, followed by measurement of lavageable total cells, macrophages, and neutrophils, and 
-glutamyltransferase activity and plasma fibrinogen in lavage fluid. Results indicate a pattern of rat strain-specific pulmonary and systemic effects that are not linked to high mass but appear to be dependent on CAP chemical composition.
ENVIRONMENTAL TOXICOLOGY | Liver Changes in East Greenland Polar Bears
Because organohalogen compounds (OHCs) are hepatotoxic, Sonne et al. (p. 1569) investigated liver histology of adult female, adult male, and subadult East Greenland polar bears (Ursus maritimus) sampled during 1999-2002. In adult females, hepatocytic intracellular fat increased significantly with concentrations of the sum of hexachlorocyclohexanes, as was the case for lipid granulomas and hexachlorobenzene in adult males. There were also many microscopic changes, including mononuclear cell infiltration. Based on these relationships and the nature of the chronic inflammation, the authors suggest that these findings were caused by aging and long-term exposure to OHCs and therefore may be used as biomarkers of OHC exposure.
CARDIOVASCULAR DISEASE | PM2.5 Source-Related Changes in Cardiac Function
Lippman et al. (p. 1575) investigated heart rate (HR) and HR variability (HRV) during 5 months using 6 hr/day, 5 day/week exposures of normal mice and a murine model for atherosclerotic disease. Mice were exposed to concentrated ambient fine particulate matter (diameter ≤ 2.5 µm; PM2.5) attributed to major PM categories [secondary sulfate (SS), resuspended soil (RS), residual oil (RO) combustion, and other]. For HR, there were significant associations for RS during exposure and for SS in the afternoon after exposure. For HRV, there were associations with RO in the afternoon after exposure and for both SS and RS late at night. The biologic bases may relate to the differential solubility of PM components.
FETAL DEVELOPMENT | Fetal Testis Development in Sheep
Sewage sludge may be applied to agricultural fields as fertilizer. Paul et al. (p. 1580) evaluated whether exposure of pregnant sheep to a mixture of environmental chemicals in sewage sludge added to pasture exerted effects on fetal testis development or function. Treatment reduced body weight by 12-15% in male and female fetuses. In treated male fetuses, testis weight was significantly reduced, as were the numbers of Sertoli cells, Leydig cells, and gonocytes, compared with control fetuses. Overall findings indicate that exposure of the developing male sheep fetus to real-world mixtures of environmental chemicals can result in major attenuation of testicular development and hormonal function, which may have consequences in adulthood.
BIOSENSORS | Transcriptional Tests of Thyroid Function In Vivo
Thyroid signaling is amenable to analysis with a transcriptional assay because thyroid hormone (triiodothyronine; T3) acts principally by modulating transcription. T3 coordinates amphibian metamorphosis, thereby providing an exceptional model for identifying thyroid-disrupting chemicals. Turque et al. (p. 1588) combined these two advantages to develop a method for following and quantifying the transcriptional action of T3 in Xenopus laevis tadpoles. A pretreatment protocol was applied to somatic and germinal transgenesis with two reporter systems. The transcriptional assay detects the thyroid-disrupting activity at environmentally relevant concentrations (10-8 M) of acetochlor, a persistent herbicide.
ENVIRONMENTAL TOXICOLOGY | CYP1A1 Expression in Arctic Beluga
Cytochrome P450 1A1 (CYP1A1) induction is related to toxic effects of polycyclic aromatic hydrocarbons in some species. Wilson et al. (p. 1594) examined CYP1A1 protein expression in organs of beluga whales from two locations in the Arctic and from the St. Lawrence estuary. These beluga populations have some of the lowest (Arctic sites) and highest (St. Lawrence estuary) concentrations of polychlorinated biphenyls in blubber of all cetaceans. The pattern and extent of CYP1A1 staining in whales from these locations were similar to those seen in animal models in which CYP1A has been highly induced. The high-level expression of CYP1A1 in the Arctic beluga suggests that this species is highly sensitive to CYP1A1 induction by aryl hydrocarbon receptor agonists.
TOXICOLOGY | Inhibition of 11β-HSD2 by Organotins
Organotins, widely used in agriculture and industrial applications, accumulate in the food chain and induce imposex in several marine species as well as neurotoxic and immunotoxic effects in higher animals. Atanasov et al. (p. 1600) demonstrate that organotins inhibit 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2), converting active 11β-hydroxyglucocorticoids into inactive 11-ketoglucocorticoids, but not 11β-HSD1, which catalyzes the reverse reaction. Enhanced glucocorticoid concentrations due to disruption of 11β-HSD2 function may contribute to the observed organotin-dependent toxicity in some glucocorticoid-sensitive tissues such as thymus and placenta.
RISK CHARACTERIZATION | Drinking-Water Nitrate and Health
Some scientists suggest that the U.S. and World Health Organization guidelines for nitrate in drinking water are overly conservative. Ward et al. (p. 1607) report on a symposium on drinking-water nitrate and health held at the 2004 International Society for Environmental Epidemiology meeting. The contribution of drinking-water nitrate toward endogenous formation of N-nitroso compounds was evaluated in terms of subpopulations with increased rates of nitrosation. The few epidemiologic studies that have evaluated intake of nitrosation precursors and/or nitrosation inhibitors have found elevated risks for colon cancer and neural tube defects associated with drinking-water nitrate concentrations below the current regulatory limit.
BIOMONITORS | Biomonitoring Recommendations
Human biomonitoring investigations have provided data on a wide array of chemicals in blood and urine and in other tissues and fluids such as hair and human milk. Bates et al. (p. 1615) report on the recommendations of an interdisciplinary panel convened in November 2004 with the charge of focusing on three specific aspects of biomonitoring: characteristics of scientifically robust studies, interpretation of data for potential risks to human health, and communication of results, uncertainties, and limitations of biomonitoring studies.
PROTEOMICS | Environmentally Responsive Proteins
Reinlib (p. 1622) summarizes a workshop convened by the National Institute of Environmental Health Sciences to solicit advice for future research into environmentally responsive proteins and pathways. The highest priorities recommended by the workshop were to support studies of structure analysis, response dynamics, modification/interaction, polymorphisms, and integrated experimental approaches. The workshop participants also saw value in improving the throughput and purity of protein samples and macromolecular assemblies.
Environmental Medicine
KIDNEY/BLADDER DISEASE | Cadmium-Induced Effects on Kidney
The cadmium exposure level that is critical for kidney effects in the general population is not defined. Åkesson et al. (p. 1627) investigated cadmium exposure in relation to tubular and glomerular function among women 53-64 years of age. Regression showed cadmium in blood and urine to be significantly associated with effects on renal tubules after adjusting for age, body mass index, blood lead, diabetes, hypertension, and regular use of nephrotoxic drugs. Tubular renal and glomerular effects occurred at lower cadmium levels than previously demonstrated. The effects were small, but they may represent early signs of adverse effects in large segments of the population.
Also see Science Selections, p. A759
Children's Health
RESPIRATORY DISEASE | Health Benefit of Air Pollution Reduction
Bayer-Oglesby et al. (p. 1632) investigated whether a moderate decline of air pollution levels in the 1990s in Switzerland was associated with a reduction in respiratory problems in school children. Adjusted for socioeconomic, health-related, and indoor factors, declining PM10 (particulate matter < 10 µm in diameter) was associated in logistic regression models with declining prevalence of chronic cough, bronchitis, common cold, nocturnal dry cough, and conjunctivitis symptoms. Changes in prevalence of sneezing during pollen season, asthma, and hay fever were not associated with the PM10 reduction. No threshold of adverse effects of PM10 was apparent because beneficial effects were observed for relatively small changes of air pollution levels.
FETAL DEVELOPMENT | Air Pollution and Birth Outcomes in Term Infants
Salam et al. (p. 1638) investigated the effects of air pollutants on birth weight mediated by reduced fetal growth among term infants. Linear mixed-effects regression indicated that a 12-ppb increase in 24-hr ozone averaged over the entire pregnancy was associated with 47.2-g lower birth weight, and this association was most robust during the second and third trimesters. A 1.4-ppm difference in first-trimester carbon monoxide exposure was associated with 21.7-g lower birth weight. First-trimester CO and third-trimester O3 exposures were associated with 20% increased risk of intrauterine growth retardation.
ENDOCRINE SYSTEM | Dioxins and Thyroid Function in Newborns
Wang et al. (p. 1645) examined the association between transplacental exposure to dioxins/polychlorinated biphenyls (PCBs) and thyroid/growth hormones in newborns. Insulin-like growth factor-1, IGF-binding globulin-3, and thyroxine (T4) 
thyroid-stimulating hormone (TSH) were associated with increased placental weight and Quetelet index. Multivariate analyses showed independently and significantly decreased free T4 TSH with increasing non-ortho PCBs. Results indicate that significant free T4 feedback alterations to the hypothalamus result from in utero exposure to non-ortho PCBs. The authors suggest routine screening of both thyroid hormone levels and thyroid function in newborns.
EXPOSURE ASSESSMENT | Pesticide Exposure of Children and Workers in Washington
Fenske et al. (p. 1651) examined urinary dimethylthiophosphate (DMTP) concentrations and composite dimethyl alkylphosphate (DMAP) concentrations from organophosphorus pesticide studies conducted in Washington State. Children of pesticide applicators had higher metabolite levels than did Seattle children and farmworker children. Metabolite levels of children in the agricultural community were elevated during periods of crop spraying. DMTP concentrations for workers engaged in apple thinning were 50 times higher than DMTP concentrations for workers sampled outside of peak exposure periods. Workers with direct pesticide contact should be the focus of health interventions, and elevated child exposures may occur during crop spraying periods and from living with a pesticide applicator.
