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Vol. LIX, No. 22
November 2, 2007
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Digest

  Results of a new study funded by NIMH may one day help scientists learn how to enhance a naturally occurring mechanism in the brain that promotes resilience to psychological stress.  
  Results of a new study funded by NIMH may one day help scientists learn how to enhance a naturally occurring mechanism in the brain that promotes resilience to psychological stress.  
Deciphering Clues for Schizophrenia Development…

Researchers have discovered major clues as to how schizophrenia develops. A study, funded by NIMH and NICHD and published in the Journal of Neuroscience, showed that schizophrenia may occur in part because of a problem in an intermittent on/off switch for a gene involved in making a key chemical messenger in the brain. By studying human brain tissue, scientists found that this gene is turned on at increasingly high rates during normal development of the prefrontal cortex, but this normal increase may not occur in people with schizophrenia. Researchers said that being able to identify mechanisms involved in the disease will help point to potential new targets for medication.

…And for Rheumatoid Arthritis Risk

Thanks to the relatively new research method of genome-wide association studies—making it possible to analyze between 300,000 and 500,000 small differences in DNA distributed throughout a person’s genetic code—researchers in the U.S. and Sweden have identified a genetic region associated with increased risk of rheumatoid arthritis (RA). The result of a collaboration between NIAMS researchers and other organizations, the study, published in the New England Journal of Medicine, reported that a region of chromosome 9 contains two genes relevant to chronic inflammation. The hope is that by learning more about the genes and their role in the disease, scientists may find ways to influence the treatment of RA, a chronic and debilitating inflammatory disease of the joints that affects an estimated 2.1 million Americans.

Getting Past Stress

Results of a new study funded by NIMH may one day help scientists learn how to enhance a naturally occurring mechanism in the brain that promotes resilience to psychological stress. In a study published online in Cell, researchers reported that in a mouse model, the ability to adapt to stress is driven by a distinctly different molecular mechanism than is the tendency to be overwhelmed by stress. There are components of similar mechanisms in the human brain, and stress can play a major role in the development of several mental illnesses. Therefore, understanding why some people succumb to stress and others prevail could help scientists explore ways of increasing stress-resistance in people who might otherwise be overwhelmed.

The Importance of Small Differences

The International HapMap Consortium has published analyses of its second-generation map of human genetic variation. In two papers published in Nature, the consortium describes how the higher-resolution map—with three times as many markers as the initial version unveiled in 2005—offers greater power to detect genetic variants involved in common disease, to explore the structure of human genetic variation and to learn how environmental factors have shaped the human genome. The consortium is a public-private partnership of researchers and funding agencies around the world; the U.S. component is led by NHGRI on behalf of 20 institutes, centers and offices at NIH that contributed funding. Though any two humans are more than 99 percent the same at the genetic level, the small fraction of genetic material that varies among people can explain individual differences in disease susceptibility, response to drugs and reaction to environmental factors.

Folic Acid and Arsenic

A new NIEHS-funded study conducted in Bangladesh found that folic acid supplements can dramatically lower blood arsenic levels in individuals chronically exposed to the contaminant through drinking water. Water contaminated with arsenic—a toxic element that is naturally present in some soils and water—currently poses a significant public health problem in at least 70 countries, and can be found in parts of the United States. In the study, published in the American Journal of Clinical Nutrition, researchers found that treatment with 400 micrograms a day of folic acid, the U.S. Recommended Dietary Allowance, reduced total blood arsenic levels in a Bangladesh study population by 14 percent. Chronic arsenic exposure is associated with risk of skin, liver and bladder cancers; skin lesions; cardiovascular disease and other adverse health outcomes.—

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