What's Up, Postdoc?
Somewhere between the world of the graduate student and that of the independent investigator is the world of the postdoctoral researcher--a world of training and preparation for a career in the sciences. This month's NIEHS News (p. A70) describes the NIEHS Trainees Assembly, an organization designed to support and guide institute postdocs as they learn the ropes of becoming a working scientist.
Better Beryllium Regs: A Work in Progress
The manufacture of beryllium alloys took off after World War II; today, some 30,000 workers in the United States alone are believed to come into daily contact with this metallic element. The Focus (p. A74) examines federal efforts to develop better exposure regulations for beryllium to protect workers from the lung diseases associated with it.
A New Era for Dam Building
The Spheres of Influence (p. A80) explains the framework set forth in a recent report by the World Commission on Dams, which looks at a more holistic approach toward assessing whether dams are the best choice for certain areas and how they can be built to be safer and more effective.
PCB- and Dioxin-Contaminated Food in Belgium
Schepens et al. (p. 101) report that 12% of Belgian chicken or pork meat samples for export from farms contain > 50 ng PCBs/g fat and that 6.5% contain > 20 ng/g fat of the sum of DDT and metabolites. The authors suggest that the toxicants originate from animal feed contaminated from recycled animal fats.
Adrenal Effects of a DDT Metabolite
Lindhe et al. (p. 105) examined steroid synthesis and secretion of mineralocorticoids and glucocorticoids in tissue slice culture from rodents. The authors showed that the bioactivation and mitochondrial toxicity of DDE metabolites observed in vivo could be reproduced ex vivo; they propose using this test system to examine the adrenocorticolytic activity of pollutants and drugs in human and animal tissues.
Diesel Exhaust Masculinizes Fetus
Pregnant rats were exposed to diesel exhaust inhalation by Watanabe and Kurita (p. 111). Additional pregnant rats were also exposed to aromatase inhibitors or testosterone to examine the mechanism of inhalation toxicity of diesel exhaust. The authors suggest that diesel exhaust inhalation may have caused inhibition of aromatase activity and synthesis, which in turn led to an accumulation of testosterone and fetal masculinization, and that the gaseous phase included the relevant toxicants.
Survey of Dietary Metal Intake
Food samples from the National Human Exposure Assessment Survey were analyzed for arsenic, cadmium, chromium, and lead by Ryan et al. (p. 121). The authors discuss the food items likely to contribute to metal intake, the implications for dietary exposure-based risk analysis, and dietary intake epidemiology.
Dermal Penetration of Pesticides
Nielsen and Andersen (p. 129) measured dermal penetration of methiocarb, paclobutrazol, and pirimicarb and the protection against dermal penetration offered by gloves made of latex or nitrile. An experimental model using in vitro static diffusion cells mounted with human skin revealed that nonylphenylethoxylate decreased penetration of the pesticides, that nitrile was more effective than latex, and that protection decreased over time and with the pesticide used.
Yeast Bioassay of Estrogenic Phenolics
A recombinant yeast estrogen assay was used by Miller et al. (p. 133) to assess the activity of 73 phenolic additives used in sunscreens, preservatives, disinfectants, antioxidants, flavorings, and perfumes. The authors report estrogenic activity in 32 compounds, with the major criteria for activity being the presence of an unhindered phenolic hydroxyl group in the para position and a molecular weight between 140 and 250 Da.
House Dust, Endotoxins, and Immunity
The proinflammatory agent ß(13)-glucan was measured in house dust from 395 German homes by Gehring et al. (p. 139). The authors found that increases in ß(13)-glucan levels were associated with carpets, keeping dogs, number of residents, cleanliness, and mold spots, and suggest that this measurement could be used as a proxy for hygiene.
Ingesting Pesticides
MacIntosh et al. (p. 145) analyzed 4-day composite duplicate diet samples of 80 individuals for the presence of 10 pesticides, and detected chlorpyrifos in 38%, malathion in 75%, and DDE in 21% of the solid food samples. The greatest frequency of occurrence was in spring and summer; chlorpyrifos and malathion frequently co-occured, and their concentrations varied with time. (Also see Science Selections, p. A85)
Particulate Measurements in Urban Sites
Roemer and van Wijnen (p. 151) measured black smoke, PM10, and PM1.0 in urban, traffic-dense, and intersection sites and found that the particle concentrations were highly correlated with location and time. The authors report that mass measurements of ambient particulate matter underestimate the exposure to particles generated by traffic.
Climate and Diarrhea in the Pacific islands
Rainwater provides available water sources in many small island states in the Pacific. Singh et al. (p. 155) examined the relationship between temperature, water availability, and diarrhea between 1986 and 1994 for 18 Pacific Island countries, and between 1978 and 1998 for Fiji. There were positive associations between diarrhea and temperature or extremes of rainfall, suggesting that global climate change would likely exacerbate illness in many cases. (Also see Science Selections, p. A84)
Environmental Sensitivities
Joffres et al. (p. 161) analyzed the frequency, severity, and type of symptoms reported by patients referred to a Canadian environmental sensitivity center. Questionnaires from 351 individuals indicated that they experienced general symptoms and those related to irritability. The authors suggest that the type and consistency of symptoms reported in response to triggering substances does not seem to fit a purely psychogenic theory.
DMSA Chelation as Mercury Biomarker
Chelation challenge with dimercaptosuccinic acid (DMSA) to measure mercury body burden in employees exposed at a chloralkali plant was reported by Frumkin et al. (p. 167). The authors found no association between past exposure or the number of dental amalgam surfaces and urinary mercury excretion before or after DMSA treatment, suggesting that this approach is not useful as a marker of past mercury exposure.
Organochlorines and Immunotoxicity
Daniel et al. (p. 173) examined the immunologic systems of patients occupationally exposed to chlorinated contaminants and observed that blood levels of PCBs, hexachlorobenzene, and hexachlorocyclohexanes were closely correlated. Exposure was only weakly correlated with immunologic abnormalities, except for hexachlorobenzene suppression of interferon-* production.
Chernobyl and Pregnancy in Finland
Auvinen et al. (p. 179) evaluated the potential association between radiation exposure from Chernobyl and the outcome of pregnancies in Finland. There was a slight decrease in the live birth rate and a slight increase in spontaneous abortion, but the authors indicate the changes were probably due to factors other than radiation exposure.
Carcinogenic Risk in Children
Charnley and Putzrath (p. 187) argue that lowering regulatory limits for chemical exposure to children because of their special susceptibilities may not achieve reasonable benefits without an accurate scientific database.
Paternal Exposure and Childhood Cancer
Feychting et al. (p. 193) evaluated the incidence of cancer in 235,635 children between birth and 14 years of age. There was an increased risk of childhood brain tumors and leukemia that was related to paternal occupational exposure to pesticides. (Also see Science Selections, p. A84)
Grand Rounds
Dodson and Levin (p. 199) report on asbestos-related disease in a foundry worker. The individual was probably exposed to asbestos through a nonasbestos mineral, which also contained a "noncommercial" asbestos. The authors caution that similar exposures may occur in settings where asbestos is not considered a risk.
Last Updated: February 20, 2001