Environews
Basic Training and Bridging the Gap
This month's NIEHS News (p. A520) looks at the 10-year Pesticides Initiative, a government-nonprofit undertaking to provide basic training to medical and nursing professionals on the effects of pesticide exposure. In other news, the Institute of Medicine Roundtable on Environmental Health Sciences, Research, and Medicine draws on the varied expertise of government agencies, academia, and industry to bridge the gap in understanding of critical environmental health issues.
Three-Part Harmony
Conservation medicine blends the best knowledge from three arenas--human health, animal health, and ecosystem health--into one discipline that seeks to elucidate the connections among the three. The Focus (p. A524) describes the growing field of conservation medicine and looks at some of the emerging problems and solutions being identified by its practitioners.
What's Behind the Bottom Line?
Cost-benefit analyses are nothing new, but fresh questions are cropping up over their use in environmental rule making by the Office of Information and Regulatory Affairs (OIRA). The Spheres of Influence (p. A530) looks at how OIRA, under helmsman John Graham, is expanding its role in cost-benefit review and becoming increasingly involved in all phases of the rule-making process.
On the Ball
High-energy ball-milling has been used for decades to process metals and other inorganics. Now scientists are seeing a new use for this technology. The Innovations (p. A534) tells how one team is using ball-milling to create organic compounds without the use of toxic solvents in a simpler, cleaner "one-pot" procedure.
Research
Mercury Preexposure Accelerates Acquired Murine Lupus
Inorganic mercury (iHg) induces autoimmune disease and exacerbates symptoms in susceptible rodent strains. Via et al. (p. 1273) used low doses of iHG in a murine model of acquired autoimmunity using normal donors and F1 recipient mice resistant to Hg-induced autoimmunity. Exposure of donor and host mice to low-dose iHg ending prior to autoimmune induction significantly worsened disease severity. (Also see Science Selections, p. A538)
PCBs and ER-ß Expression in Rat Hypothalamus
Polychlorinated biphenyl (PCB) exposure during development can disrupt the reproductive axis, and estrogen receptor-ß (ER-ß) may mediate effects of endocrine-disrupting chemicals. Salama et al. (p. 1278) report that exposure of developing rats to a PCB mixture reduces the number of ER-ß-expressing cells in the anteroventral periventricular nucleus, a sexually dimorphic region of the hypothalamus, but not in the supraoptic nucleus, another hypothalamic region.
Bias in a GAM for Spatial Data
The generalized additive model (GAM) has been extended from time-series data to spatial data on health effects of air pollution. Ramsay et al. (p. 1283) suggest that concurvity in spatial data can lead to underestimation of the standard error of the air pollution effect. The magnitude and direction of the bias in the air pollution effect depend, in part, on the nature of the concurvity.
Cellular Effects Induced by Mexico City's PM2.5 and PM10
Transition metals and endotoxins associated with particulate matter (PM) may influence cytotoxic and proinflammatory effects. Osornio-Vargas et al. (p. 1289) report major differences in in vitro responses of murine monocytes to PM2.5 and PM10. PM2.5 induces cytotoxicity through an endotoxin-independent mechanism mediated by transition metals, and PM10, with relatively high levels of endotoxin, induces proinflammatory cytokine release via an endotoxin-dependent mechanism.
Plasticity as a Biomarker of Neurotoxic Damage
Modification of brain structure in response to experience provides indices for plasticity in the healthy brain. Wallace et al. (p. 1294) used methylazoxymethanol acetate exposures in rats during gestation to test experience-dependent plasticity as a biomarker for developmental neurotoxicity. Results indicate that plasticity could be an efficient way to detect subtle neurotoxicity in the developing brain at much lower doses than conventional structural measures.
Biological Activity of PM10 Extracts from the U.S.-Mexico Border
Arrieta et al. (p. 1299) measured biological activity of PM10 from sites in El Paso, Texas, Juarez, Chihuahua, Mexico, and Sunland Park, New Mexico, using in vitro assays. PM10 correlated with biological activity, the highest activity being from the Juarez site. Chemical analysis of extracts from Juarez also indicated concentrations of polycyclic aromatic hydrocarbons higher than those reported in most U.S. metropolitan areas.
Dietary Persistent Organics Exposure in Uzbekistan
Muntean et al. (p. 1306) examined food as a potential source of elevated persistent organic compounds previously found in breast milk and cord blood from women in Karakalpakstan in western Uzbekistan. Food traditionally grown, sold, and consumed appears to be a major route of human exposure to several persistent toxic contaminants including the most toxic of dioxins.
Temperature, Air Pollution, and Hospitalization among the Elderly
Koken et al. (p. 1312) compared daily cardiovascular hospital admission for people > 65 years of age with measures of temperature, particulate matter, and gaseous pollution in Denver, Colorado. Ozone was associated with hospitalization for myocardial infarction, coronary atherosclerosis, and pulmonary heart disease. Higher temperatures were associated with hospitalization for myocardial infarction and congestive heart failure and with a decrease in visits for coronary atherosclerosis and pulmonary heart disease.
U.S. EPA Reference Values and Risk
The U.S. Environmental Protection Agency generally uses reference doses (RfDs) or reference concentrations (RfCs) to assess exposure risks for noncancer health end points. Castorina and Woodruff (p. 1318) used results from recently adopted benchmark dose modeling approaches for developing RfDs/RfCs to estimate the risk levels associated with exposures at the RfD/RfC. The findings call into question the assumption that established RfD and RfC values represent negligibly small risk levels.
Environmental Medicine
Long-Term Neurologic Outcomes of Toxic Oil Syndrome
Toxic oil syndrome (TOS) resulted from consumption of rapeseed oil denatured with 2% aniline and affected over 20,000 persons in Spain during 1981. Using quantitative neurologic tests, Posada de la Paz et al. (p. 1326) found significant adverse central and peripheral neurologic effects in a group of TOS patients 18 years after exposure when compared with a nonexposed group. (Also see Science Selections, p. A538)
Amyotrophic Lateral Sclerosis, Lead, and Genetic Susceptibility
Lead exposure may be associated with increased risk of amyotrophic lateral sclerosis (ALS), and polymorphisms in -aminolevulinic acid dehydratase (ALAD) and the vitamin D receptor may affect susceptibility to lead exposure. Findings reported by Kamel et al. (p. 1335) suggest that genetic susceptibility conferred by polymorphisms in ALAD may affect ALS risk, possibly through a mechanism related to internal lead exposure. (Also see Science Selections, p. A539)
Children's Health
Children's Health in Southeast Asia and the Western Pacific
Half of the world's children live in Southeast Asia and the Western Pacific. Environmental hazards range from waterborne bacterial contamination and wood smoke to recent threats such as asbestos, groundwater arsenic, methyl isocyanate, untreated manufacturing wastes, pesticides, and atmospheric lead emissions. To address these problems, pediatricians, environmental scientists, and public health workers are building research and prevention programs in children's environmental health (Suk et al., p. 1340).
Mouse Allergen in Homes
Quantifying mouse allergen levels in homes could augment our understanding of inner-city asthma. Chew et al. (p. 1348) found significant neighborhood differences in levels of mouse allergen and reports of rodents in homes. Mouse allergen was prevalent among inner-city apartments, and the predictive value of mouse sightings was high. However, high levels of mouse allergen were also found in many homes where mothers reported never seeing mice.
Low Birth Weight and PCB-Contaminated Sites
Baibergenova et al. (p. 1352) tested whether residents in zip codes containing or bordering polychlorinated biphenyl (PCB) sites are at increased risk of low birth weight babies. After adjusting for infant sex and mother's age, race, weight, height, education, income, marital status, and smoking, there was significant 6% increased risk of giving birth to a male infant of low birth weight in the PCB-related zip codes.
Regulatory Acceptance of (Q)SARs
Quantitative structure-activity relationships [(Q)SARs] are simplified mathematical representations of complex chemical-biological interactions that can be divided into two major types: QSARS and SARS. They may have potential as predictive models for chemical classification and risk assessment. To fulfill the potential, the predictions need to be scientifically valid, reliable, and accepted by decision makers. This mini-monograph (p. 1358, 1361, 1376, and 1391) provides an overview of many current issues.