Environews
FOCUS | Nutrigenomics: The Genome–Food Interface
Determining clearly defined cause-and-effect connections is key to establishing preventive measures to help us live longer, healthier lives. Recent insights into the role of genetics in the environment–health interplay are providing helpful clues in unraveling this complex relationship, and are inspiring the creation of more multidisciplinary, gene-based processes of analysis. One of these is nutrigenomics, which examines how the nutrients we consume in our diet affect our health at the genomic level. This article (p. A582) takes a look at this emerging approach to health.
INNOVATIONS | Blue Power: Turning Tides into Electricity
Throughout history, the waters of the world have served as valuable food sources. Now, a new benefit from waters is appearing on the horizon: electricity generated from wave and tidal energy. Although still in the early stages of development and use, its predictability and benign environmental imprint have some experts considering power derived from the Earth's waters to be a potentially long-term, reliable source of renewable energy. This article (p. A590) examines the technology behind wave and tidal energy and discusses government regulation's effect on development and future applications.
Review
BIOSENSORS | Electrochemical Sensors Biomonitoring for Lead
Quantitative technologies for measuring xenobiotic exposure are needed to support the development and implementation of biological monitoring programs. Despite a considerable effort to identify and eliminate Pb exposure sources, this metal remains a significant health concern. Yantasee et al. (p. 1683) highlight the development and validation of two classes of metal analyzers for the voltammetric detection of Pb. These analyzers have been optimized to accurately detect Pb in urine, blood, and saliva. These improved and portable analytical sensor platforms will improve our ability to conduct biological monitoring programs to understand the relationship between chemical exposure assessment and disease outcomes.
ASTHMA | House Dust Mite Reduction and Asthma Prevention
To assess whether any household dust reduction intervention has the effect of increasing or decreasing the development or severity of atopic disease, Macdonald et al. (p. 1691) reviewed 14 studies identified through a search of EMBASE, MEDLINE, and the Cochrane Central Register of controlled trials, using no date or language restrictions. Their review found that evidence is not sufficient to suggest implementing hygiene measures in an attempt to improve outcomes in existing atopic disease, but that interventions from birth in those at high risk of atopy are useful in preventing diagnosed asthma but not parentally reported wheeze.
Research
CARDIOVASCULAR DISEASE | Lead Exposure and Pulse Pressure
In industrialized societies, pulse pressure increases with age as a manifestation of arterial stiffening. Lead accumulates in the vasculature and is associated with vascular oxidative stress, which can promote functional and structural vascular disease. a href="/docs/2007/10350/abstract.html">Perlstein et al. (p. 1696) tested the hypothesis that cumulative lead exposure, measured with K-X-ray fluorescence, is associated with pulse pressure in a cohort of community-exposed adult men. Data indicate that lead exposure may contribute to this observed increase in pulse pressure. Lead accumulation may contribute to arterial aging, perhaps providing mechanistic insight into the observed association of low-level lead exposure with cardiovascular mortality.
RISK ASSESSMENT | Effect of PM2.5 Nickel and Vanadium on PM10 Mortality Effect Estimates
Short-term effects of particulate matter (PM) can vary by location, possibly reflecting regional differences in mixtures. Using 1987–2000 effect estimates, Dominici et al. (p. 1701) reestimated the relationship between effects of county-specific lag-1 PM10 (PM with aerodynamic diameter < 10 µm) on mortality, and county-specific nickel or vanadium PM2.5 average concentrations. Their analysis does not contradict the hypothesis that nickel or vanadium may increase the risk of PM to human health, but it highlights the sensitivity of findings to particularly influential observations.
MIXTURES | Health Impacts of Estrogens
Environmental estrogens in wastewater treatment work (WwTW) effluents are well established as the principal cause of reproductive disruption in wild fish populations, but their possible role in the wider health effects of effluents has not been established. Filby et al. (p. 1704) assessed the contribution of estrogens to adverse health effects induced in a model fish species (fathead minnow) by exposure to WwTW effluents, and they compared the effects of an estrogen alone and as part of a complex mixture (i.e., spiked into effluent). Data reveal a clear link between estrogens present in effluents and diverse, adverse, and sex-related health impacts.
REPRODUCTIVE HEALTH | Uranium Mimics Estrogen
Uranium's deleterious impact on human health has been linked to its radioactive and heavy metal chemical properties. Raymond-Whish et al. (p. 1711) investigated the hypothesis that uranium, similar to other heavy metals such as cadmium, acts like estrogen by exposing intact, ovariectomized, and pregnant mice to depleted uranium in drinking water. Data support the conclusion that uranium is an endocrine-disrupting chemical. Decades of uranium mining and milling in the Colorado plateau in the Four Corners region of the American Southwest make the uranium concentration and route of exposure used in these studies environmentally relevant. Therefore, populations exposed to environmental uranium should be followed for increased risk of fertility problems and reproductive cancers.
Also see Science Selections, p. A595
EXPOSURE ASSESSMENT | Effects of Dietary Phytoestrogen on Time of Vaginal Opening in Rodents
In studies evaluating endocrine-disrupting compounds, the optimum test diet and rodent species/strain are critical. Thigpen et al. (p. 1717) conducted studies to evaluate sensitivity of rodent species and the effects of diets varying in phytoestrogen content (e.g., genistein, daidzein) on the time of vaginal opening (VO) in CD-1 mice, Fischer 344 rats, and CD Sprague-Dawley rats. The profound effects of dietary phytoestrogens on the time of VO, an estrogen-sensitive marker, indicates that a standardized open-formula phytoestrogen-free diet containing a low metabolizable energy level should be used to optimize the sensitivity of estrogenic bioassays.
Also see Science Selections, p. A594
GENE EXPRESSION | THF-Diols and PLA2, LOX, and COX Gene Expression
An isomeric mixture of tetrahydrofurandiols (THF-diols; 9,12-oxy-10,13-dihydroxyoctadecanoic acid and 10,13-oxy-9,12-dihydroxyoctadecanoic acid) characterized in ground corncob bedding material has been shown to interfere with male and female sexual behavior and ovarian cyclicity in rats and to stimulate estrogen receptor (ER)-positive and ER-negative breast cancer cell proliferation. Markaverich et al. (p. 1727) assessed the effects of enzyme inhibitors on cell proliferation in response to THF-diols or estradiol in MCF-7 human breast cancer cells in vitro. Results show that these compounds are likely to be involved in the mechanism of action of THF-diols in MCF-7 cells.
BIOMONITORS | O3 Effects on Lipid Peroxidation and Antioxidant Capacity
There is growing evidence for the role of oxidative damage in chronic diseases. Although exposure to the oxidant pollutant ozone is extremely common, few studies have examined whether O3 induces oxidative stress in humans. Chen et al. (p. 1732) assessed the effect of short- and long-term O3 exposures on biomarkers of oxidative stress. They analyzed biomarkers of lipid peroxidation [8-isoprostane (8-iso-PGF)] and antioxidant capacity (ferric reducing ability of plasma) in healthy college students with broad ranges of ambient O3 exposure and found that long-term exposure to O3 is associated with elevated 8-iso-PGF. Results suggest that 8-iso-PGF is a good biomarker of oxidative damage.
Also see Science Selections, p. A595
RISK CHARACTERIZATION | Gentamicin-Resistant E. coli High among U.S. Poultry Workers
The application of antimicrobials for therapy, prophylaxis, and growth promotion in broiler chicken production has been associated with the emergence and dissemination of antimicrobial-resistant enteric bacteria. Although human exposure to antimicrobial-resistant bacteria through food has been examined extensively, little attention has been paid to occupational and environmental routes of exposure. Price et al. (p. 1738) measured the relative risk for colonization with antimicrobial-resistant Escherichia coli among poultry workers and community referents. Poultry workers had 32 times the odds of carrying gentamicin-resistant E. coli than did referents. Poultry workers were also at significantly increased risk of carrying multidrug-resistant E. coli.
NEURODEVELOPMENT | Maternal–Fetal Transfer of Domoic Acid
Prenatal exposure to asymptomatic doses of domoic acid (DA) causes learning and memory deficits later in life; Maucher and Ramsdell (p. 1743) measured the distribution of DA in maternal plasma and brain, prenatal brain, and amniotic fluid 1 hr after exposure, a time frame that normally encompasses acute seizure behavior. Pregnant rats were given a single intravenous dose of DA on either gestational day (GD) 13 or GD20, which correspond to the beginning of rat embryo neurogenesis and the last day of gestation, respectively. DA crosses the placenta, enters brain tissue of prenates, and accumulates in the amniotic fluid. Thus, amniotic fluid appears to be useful in monitoring DA exposure.
DIABETES | Diabetes and Organochlorine Pesticide Exposure
The prevalence of diabetes is higher among Mexican Americans than among non-Hispanic whites, and higher serum levels of organochlorine pesticides have been reported in Mexican Americans. However, few studies have explored the association between pesticide exposure and diabetes. Cox et al. (p. 1747) examined the association between self-reported diabetes and serum concentrations of organochlorine pesticides among Mexican Americans residing in the southwestern United States from 1982 to 1984. Results suggest that higher serum levels of certain organochlorine pesticides may be associated with increased prevalence of diabetes. Additional studies that include more extensive clinical assessment are needed to confirm this association.
RISK CHARACTERIZATION | Air Pollution and Conjunctival Goblet-Cell Hyperplasia
Ocular mucosa is constantly exposed to external environment, and chronic exposure to air pollution may affect the ocular surface. Novaes et al. (p. 1753) assessed the effect of air pollution on the ocular surface, combining determinations of individual exposure and conjunctival impression cytology. They detected a positive and significant association between exposure to air pollution and goblet cell hyperplasia in human conjunctiva. The combination of simple measurements of exposure and impression cytology was an effective and noninvasive approach to characterizing human response to ambient levels of air pollution.
GENE EXPRESSION | In Utero ETS Alters Adult Lung Gene Expression
In utero environmental tobacco smoke (ETS) exposure exacerbates initial lung responses of adult mice to ovalbumin (OVA), a common allergen in rodent models of allergic asthma. Rouse et al. (p. 1757) tested the hypothesis that in utero ETS exposure alters expression of genes (including asthma-related and inflammatory genes) in the lung of adult mice and that this differential expression is reflected in differential respiratory and immune responses to nontobacco allergens. The differential lung gene expression reported in this study is consistent with previously reported functional changes in lungs of mice exposed in utero to ETS and as adults to the nontobacco allergen OVA.
BIOMONITORS | Newborn Blood Spots and Environmental Research
Dried blood spots (DBS), which are routinely collected from newborns in the United States by a heel stick, are screened for congenital errors of metabolism and other disorders. More states are storing residual spots and making them available for research purposes. DNA extraction from the DBS has been widely applied; however, the development of methods to measure a range of environmental toxicants in DBS has been a more recent goal for laboratory scientists and epidemiologists. Olshan (p. 1767) report on a meeting convened to examine the utility of DBS to measure environmental exposures through various analytical methods.
POPULATION HEALTH | Pacific Rim Health and Environmental Sustainability
The coastal zone of the Pacific Rim is home for about a third of the world's population. Disproportionate growth has produced a disproportionate share of related environmental difficulties. As the region searches for acceptable compromises between growth and environmental quality, its influence on global environmental health is certain to increase. Arnold et al. (p. 1770) report on the Eleventh International Conference of the Pacific Basin Consortium, which was held to discuss regional challenges to sustainable growth. Topics included included management of arsenic in potable waters, air quality, climate change, pesticides, mercury, and electronics industry waste—each with emphasis on relationships to human health.
Environmental Medicine
NEURODEGENRATIVE DISEASE | Metabolic Disorder Presenting as Manganism
Manganese, a trace element, is essential for physiologic functioning but is neurotoxic at high doses. Common exposure sources include dietary intake as well as drinking water in some regions; toxicity is most often associated with inhalation exposures in occupational settings. Sahni et al. (p. 1776) described the investigation of a pediatric case of manganism using both clinical and environmental assessment methods. The combined evidence of the environmental assessment and biomonitoring of blood Mn levels supported a seasonal ingestion exposure source. This report adds to the emerging body of evidence linking neurologic effects to ingestion exposure to Mn.
Children's Health
ENDOCRINE SYSTEM | Organohalogens and Thyroid Hormones in Cord Blood
Thyroid hormones are important regulators of brain development. During critical periods of development, even transient disorders in thyroid hormone availability may lead to profound neurologic impairment. Animal experiments have shown that certain environmental pollutants, including heavy metals and organochlorine compounds such as polychlorinated biphenyls (PCBs) and dioxins, can interfere with thyroid hormone homeostasis. Maervoet et al. (p. 1780) examined the possible relationships between concentrations of environmental pollutants and thyroid hormone levels in human umbilical cord blood. Results suggest that environmental chemicals may affect the thyroid system of human neonates.
CANCER | Pesticides and Childhood Leukemia and Lymphoma
Rudant et al. (p. 1787) investigated the role of household exposure to pesticides in the etiology of childhood hematopoietic malignancies using data generated in the national registry-based case–control study ESCALE. Maternal household use of pesticides during pregnancy and paternal use during pregnancy or childhood were reported by the mothers in a telephone questionnaire, in which insecticides, herbicides, and fungicides were distinguished. Findings strengthen the hypothesis that domestic use of pesticides may play a role in the etiology of childhood hematopoietic malignancies. The consistency of the findings with those of previous studies on acute leukemia raises the question of whether pesticides should be used by pregnant women.
Also see Science Selections, p. A594
RISK CHARACTERIZATION | Determinants of Fetal Exposure to PCBs and PBDEs
Recent studies have reported blood levels of polybrominated diphenyl ethers (PBDEs) in the U.S. population; however, information is limited on neonatal levels and on the relationship between PBDEs and polychlorinated biphenyl (PCB) exposures. To characterize levels and determinants of fetal exposure to PBDEs and PCBs among newborns from Baltimore, Maryland, Herbstman et al. (p. 1794) analyzed umbilical cord blood for 8 PBDEs and 35 PCBs from infants delivered at the Johns Hopkins Hospital. Maternal and infant characteristics were abstracted from medical records. Many of the factors investigated were independent predictors of both PBDE and PCB levels, but in some cases the direction of associations was different.
FETAL DEVELOPMENT | Chernobyl: Radiation and Missing Newborn Boys
In the Czech Republic, the number of newborn boys was higher than that of girls each month from 1950 to 2005. The only exception was November 1986, when the number of newborn boys was significantly reduced. Peterka et al. (p. 1801) examined whether the decrease in the male birth ratio in November 1986 correlated with the level of radiation in eight Czech regions after the Chernobyl disaster. The number of newborn boys was decreased in the six eastern regions where the level of radiation was high, but the number was not reduced in the two western regions where the radioactivity was markedly lower. This decrease in male births during November 1986 was probably caused by thyroid damage due to the uptake of radioiodine (131I) into the fetal thyroid during the third month of gestation.