Environmental Factor, June 2005, National Institute of Environmental Health Sciences
DERT Papers of the Month - April 2005
1) Weil M, Bressler J, Parsons P, Bolla K, Glass T, Schwartz B. Blood mercury levels and neurobehavioral function. JAMA. 2005 Apr 20;293(15):1875-82.
Implications: The current blood-mercury standard established by the EPA for children and women of childbearing age is 5.8 micrograms/liter, which is higher than the average level for this study's participants. The researchers are quick to point out that this study should not change standards of mercury exposure and consumption, which are currently under debate. Current standards are meant to protect infants and children whose brains are still developing and possibly susceptible to low levels of mercury. However, these findings do suggest that a threshold level of mercury exposure may exist. Further research will be necessary to confirm these results and to determine in any change in current standards is warranted.
2) Cai S, Xu Y, Cooper RJ, Ferkowicz MJ, Hartwell JR, Pollok KE, Kelley MR. Mitochondrial targeting of human O6-methylguanine DNA methyltransferase protects against cell killing by chemotherapeutic alkylating agents. Cancer Res. 2005 Apr 15;65(8):3319-27.
Implications: These results suggest a potential strategy for reducing the harmful side effects of chemotherapy by making healthy cells more resistant to alkylating drugs. They imply that it may be possible to engineer such cells and introduce them into patients prior to beginning chemotherapeutic regimens. They suggest that DNA repair enzymes such as MGMT are promising focuses of such strategies and that mitochondria, as well as nuclei, are equally important targets of these enzymes.
3) Unsal-Kacmaz K, Mullen TE, Kaufmann WK, Sancar A. Coupling of human circadian and cell cycles by the timeless protein. Mol Cell Biol. 2005 Apr;25(8):3109-16.
Implications: While there is still much to be learned about the function and control of Timeless protein, these results prove that it indeed acts in the control of the circadian clock and cell cycle by interacting with circadian clock proteins and playing an important role in the DNA damage response. Therefore, it is a molecular link between circadian rhythms and the cell cycle.
4) TM Burbacher, Shen DD, Liberato N, Grant KS, Cernichiari E, and Clarkson T. 2005. Comparison of Blood and Brain Mercury Levels in Infant Monkeys Exposed to Methylmercury or Vaccines Containing Thimerosal Environ Health Perspect: doi:10.1289/ehp.7712. [Online 21 April 2005]
Implications: The authors conclude that knowledge of the fate and transport of methylmercury is not a suitable surrogate for risk assessments for exposure to thimerosal. Therefore, additional research is necessary to fully characterize the biotransformation of thimerosal so that a meaningful interpretation of any developmental effects from immunization with thimerosal-containing vaccines can be determined.
5) Kegler MC, Malcoe LH. Anti-smoking socialization beliefs among rural Native American and White parents of young children. Health Educ Res. 2005 Apr;20(2):175-84.
Implication: The study's findings indicate that methods to promote anti-smoking socialization beliefs of parents with a high school education or less may be important in preventing children from beginning to smoke in low income rural communities with high smoking rates. Although limited in size and scope, this study provides evidence that future research should focus on methods to increase parental anti-smoking communication of beliefs and whether these methods will result in decreased rates of smoking onset.