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Vol. LXI, No. 4
February 20, 2009

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  New research could lead to better drugs for inducing sleep when it is needed, and for staving off sleep when it is dangerous.  
  New research could lead to better drugs for inducing sleep when it is needed, and for staving off sleep when it is dangerous.  

Astrocytes Usher Us to Lalaland

Brain cells called astrocytes help cause the urge to sleep that comes with prolonged wakefulness, according to a study in mice, funded by NINDS, NIMH and NIA. The cells release adenosine, a chemical known to have sleep-inducing effects that are inhibited by caffeine. “Millions of Americans suffer from disorders that prevent a full night’s sleep, and others—from pilots to combat soldiers—have jobs where sleepiness is a hazard,” says Dr. Merrill Mitler of NINDS. “This research could lead to better drugs for inducing sleep when it is needed, and for staving off sleep when it is dangerous.” The study appeared Jan. 29 in Neuron. Although the exact purpose of sleep is unknown, everyone seems to need it. Some research suggests sleep strengthens memories by adjusting the connections between neurons. As the waking hours tick by, all animals experience an increasing urge to sleep, known as sleep pressure. If sleep is delayed, a deep, long sleep usually follows as the body’s means of compensating. Prior studies pointed to adenosine as a trigger for sleep pressure. The chemical accumulates in the brain during waking hours, eventually helping to stimulate the unique patterns of brain activity that occur during sleep. This study is the first time a non-neuronal cell within the brain has been shown to clearly influence behavior.

Huge Burden of Diabetes Revealed in New Data

Nearly 13 percent of U.S. adults age 20 and older have diabetes, but 40 percent of them have not been diagnosed, according to NIH and CDC epidemiologists, whose study includes newly available data from an oral glucose tolerance test (OGTT). Diabetes is especially common in the elderly: nearly one-third of those age 65 and older have the disease. An additional 30 percent of adults have pre-diabetes—elevated blood sugar not yet in the diabetic range. Researchers reported these findings in the February issue of Diabetes Care. The study compared results of two national surveys that included a fasting blood glucose (FBG) test and 2-hour glucose reading from an OGTT. The OGTT gives more information about blood glucose abnormalities than the FBG test, which measures blood glucose after an overnight fast. The FBG test is easier and less costly than the OGTT, but the 2-hour test is more sensitive in identifying diabetes and pre-diabetes, especially in older people.

Arthritis Drug in Trial Against Diabetes

Researchers in 20 medical centers across the country are enrolling adults with type 2 diabetes who have poorly controlled blood glucose to participate in a clinical study. Funded by NIDDK, the study is investigating whether salsalate—an anti-inflammatory drug used for years to manage arthritis pain—can reduce blood glucose levels in people with type 2 diabetes. If successful, the trial could lead to an effective, inexpensive way to treat the most common form of diabetes.

Ozone Wheezing: New Cause, Potential Treatments ID’d

Researchers at NIEHS and Duke University have discovered a cause of airway irritation and wheezing after exposure to ozone, a common urban air pollutant. Using an animal model, scientists found several ways to stop the airways from narrowing. These findings point to potential new targets for drugs that may eventually help physicians better treat emergency room patients suffering from wheezing, coughing and shortness of breath. Ozone is formed in the inner atmosphere, in the presence of sunlight, from pollutants emitted from vehicles and other sources. Exposure occurs when people inhale air containing ozone. About 4,500 hospital admissions and 900,000 school absences each year are attributed to ozone exposure, especially on high-ozone alert days. “We found that it is not the ozone itself that causes the body to wheeze, but the way the lungs respond to ozone,” said Dr. Stavros Garantziotis of NIEHS, lead author of the paper published online in the Journal of Biological Chemistry. Animals exposed to ozone produce and release high amounts of a sugar known as hyaluronan, which researchers found to be directly responsible for causing the airways to narrow and become irritated. The sugar may also contribute to asthma symptoms in humans. The researchers found several proteins that can mediate the hyaluronan effect and can be used as treatment targets.—

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