An Eye on Iota
This month's NIEHS News (p. A310) describes recent findings about polymerase , a newly discovered enzyme that scientists believe may play an important role in DNA repair and damage-induced mutagenesis. The section also includes a profile of the recently formed Environmental Autoimmunity Group.
A Global Craving for Meat
One of two Focus articles this month (p. A312) looks at the increasing worldwide demand for animal products and the questions it raises about the effect on the environment.
One Fish, Two Fish, Farm Fish, Food Fish
The second Focus article (p. A318) examines aquaculture, the seaside version of livestock production. Farming fish and other seafood can provide an inexpensive source of animal protein for hungry people, but mismanaged aquaculture operations can cause more harm than good.
Too Many Cooks in the Kitchen?
Despite the fact that some 12 different federal agencies and their state counterparts oversee food safety in the United States, this country sees about 76 million cases of food contamination illness each year. The Spheres of Influence (p. A324) deconstructs the tangle of food safety regulation in the United States.
Silk Purses from Sows' Ears
A recent government-industry partnership in North Carolina is funding research into new technologies, described in the Innovations (p. A328), for managing hog waste to minimize environmental effects.
Marine Swimming Sickness
Henrickson et al. (p. 645) reviewed marine recreational and occupational activities related to gastrointestinal, respiratory, dermatologic, and eye, ear, nose, and throat infections in humans. The authors hypothesize that increases in illness may be related to degradation of the environment, and they discuss factors that may contribute to illness, economic costs, water quality monitoring, and policy implications. (Also see Science Selections, p. A332)
Insecticide Neurotoxicity in Sea Urchins
Buznikov et al. (p. 651) used sea urchin embryos to examine the cellular mechanism of action of chlorpyrifos and to delineate the critical period of developmental vulnerability. Chlorpyrifos was most toxic at the blastula stage. The cholinergic and signal-related mechanisms of toxicity of chlorpyrifos were similar to those in the mammalian embryonic central nervous system, indicating that the invertebrate system could be used as a screening procedure and to delineate mechanisms that are vulnerable during embryonic development.
Human Fatalities from Cyanotoxins
Water used in dialysis of patients in Caruaru, Brazil, culminated in the deaths of 76 of 100 patients, with the cause of 52 deaths attributed to hepatotoxins in the clinic's water source (Carmichael et al., p. 663). Analyses showed that microcystins -YR, -LR, and -AR were present in liver concentrations at 19.5 times the World Health Organization guidelines for cyanotoxins. (Also see Science Selections, p. A332)
Disturbed Pheromones and Amphibian Decline
Park et al. (p. 669) hypothesized that low concentrations of environmental contaminants may limit pheromonal communication and disrupt reproduction in amphibian populations. Low doses of endosulfan disturbed mate choice and mating success in female red-spotted newts by impairing the pheromone system, suggesting that such subtle effects in reproduction could contribute to the population decline.
Developmental Exposure of Rats to Bisphenol A
Perinatal exposure of Sprague-Dawley rats to low concentrations of bisphenol A increased body weights of male and female offspring. These effects were apparent soon after birth and persisted into adulthood (Rubin et al., p. 675). Estrous cyclicity and plasma luteinizing hormone were also altered in females, indicating an increased sensitivity to bisphenol A during the perinatal period.
Medaka Used to Predict Reproductive Toxicity
Cheek et al. (p. 681) exposed medaka fish to the environmental estrogen DDT at 2 or 8 weeks posthatch and examined them for vitellogenin (VTG) synthesis and other reproductive variables. The authors found that 8-week DDT exposure induced vitellogenin expression, caused a female-skewed sex ratio, and reduced fertility and hatching success. They suggested that VTG expression could be interpreted as a warning for reproductive toxicity, but also warned that absence of expression did not mean there were no other reproductive consequences.
Estrogenic Isoflavones from Soygerm
De Boever et al. (p. 691) modified the yeast estrogen screen by adding incubation steps to reduce the assay time by 1 day. Estrogenic compounds were incubated 24 hr with a high amount of yeast and a mixture of cycloheximide and a chromogenic substrate indicative of estrogenic activity. The estrogenic activities of bisphenol A, methoxychlor, p,p´-DDT, and isoflavones were confirmed; DDT estrogenic activity was only detected using this protocol.
Estrogenic Activities of Styrene Oligomers
The estrogenic activities of styrene oligomers were investigated by Ohyama et al. (p. 699) using tumor cell and binding assays. The authors found that because certain styrene oligomers had estrogenic activity in MCF-7 human tumor cells and a binding affinity for human estrogen receptors, these compounds could act as endocrine disruptors.
Modeling Tumor Incidence in Europe
Benigni et al. (p. 705) constructed a model of the differences in cancer incidences in males and females between countries in Europe and between provinces in Italy using social, economic, and cultural indicators as correlates. The authors suggest that the cancers were predominantly environmental in origin and stress the importance of relating cancer patterns to societal determinants.
Tobacco Smoke Affects Heart Rate
Pope et al. (p. 711) evaluated heart rate variability after acute environmental tobacco smoke (ETS) exposure in smoking areas in an airport. Nicotine and respirable suspended particle concentrations were monitored as well. ETS exposure was negatively associated with all measures of heart rate variability and resulted in approximately a 12% reduction in heart beat intervals, suggesting that altered cardiac autonomic function is part of the mechanism linking ETS exposure and cardiac toxicity. (Also see Science Selections, p. A333)
Monitoring Brevetoxin Exposure
Fairey et al. (p. 717) developed an improved method to monitor brevetoxins in living marine species, protected species, and humans using a receptor binding assay. The authors used blood collection cards to extract and identify toxin activity, and they used liquid chromatography-mass spectrometry to confirm specific brevetoxin congeners in positive samples.
Cancer near Nuclear Plants in Spain
López-Abente et al. (p. 721) examined 12,215 cancer deaths that occurred between 1975 and 1993 in 275 towns within 30 km of Spain's four nuclear power plants and four nuclear fuel centers. Excess lung and renal cancer mortality was associated with the uranium cycle facilities, suggesting the need for monitoring the health of populations in areas near nuclear facilities.
Uptake of PCBs and Lindane in Intestinal Cells
Oomen et al. (p. 731) investigated the oral bioavailability of contaminants using epithelial Caco-2 cells in an in vitro model. The authors report that PCB and lindane uptake from artificial media is dose dependent and that bile, oleic acid, and digestive proteins contribute to uptake flux toward the cells. They suggest that mobilization from soil is the most important step for oral bioavailability of contaminants in children exhibiting hand-to-mouth behavior.
Tumorigenic Effects of PCB-DDT-DDE in Rats
A mixture of DDT, DDE, and 19 PCBs based on concentrations in breast milk of Canadian women was administered to 1- to 20-day-old rats at 10, 100, and 1,000 times the levels ingested by nursing babies. Desaulniers et al. (p. 739) reported that neonatal exposure to high concentrations of organochlorines favored the development of methylnitrosourea-induced mammary lesions but also delayed the development of palpable tumors in rats.
Environmental Effects on Sex Ratios
Jongbloet et al. (p. 749) evaluated the sex ratio of newborns previously described by Finnish investigators and found that changes in male proportions preceded the period of industrialization and the introduction of pesticides or hormonal drugs. The authors suggest that causation by environmental exposures was unlikely and that the postwar decline of the male:female birth ratio was parallel with perinatal mortality and morbidity, congenital anomalies, and constitutional diseases, indicating a common etiology for the changes.
Reduced Sperm Motility after Exposure to Solvents
Chang et al. (p. 753) report on reduced sperm motility in a laboratory worker who had been exposed to solvents during a ventilation system shutdown. The authors determined that the worker could have been exposed to spermatotoxic levels of chloroform.
Last Updated: July 25, 2001