Discoveries

DISCOVERIES

April 08, 2005

In Brief

Partial eclipse tonight

The southern United States will be treated to a solar eclipse tonight at dinnertime, but even with safe viewing equipment and clear skies, Marylanders will see just a fraction of it.

The moon's shadow will race across the Pacific Ocean, making landfall in Costa Rica and Panama before crossing the northern end of South America. There, the eclipse will be total, or "annular," with the moon blocking all but the outermost ring of the sun's disk.

Between here and there, it will be a partial eclipse. In San Juan, Puerto Rico, 60 percent of the sun will be darkened. Miami will see a 30 percent eclipse. In Baltimore, the moon will nip barely 1 percent from the sun's disk, from 6:01 p.m. to 6:37 p.m.

More than just talk

Talk therapy can work as well as antidepressants in severely depressed people, and it should also be used as a first line of defense, University of Pennsylvania researchers concluded in a study published Monday.

In a study of 240 patients, researchers found that cognitive therapy, a type of treatment that teaches patients to think more realistically, worked as well as a popular antidepressant for moderate to severe depression.

Patients who got four months of cognitive therapy also had about the same relapse rate a year later as people who took Paxil (paroxetine) the whole time. If people quit taking Paxil after four months, their relapse rate was twice that of therapy patients'.

As a result, the authors from Penn and Vanderbilt University contend, cognitive therapy is cheaper than antidepressants in the long run. The research was published in the Archives of General Psychiatry.

Thyroid conference

Thyroid disease pops into the news when celebrities such as Supreme Court Justice William H. Rehnquist, former President George H.W. Bush and his wife, Barbara Bush, are diagnosed, but it is a family of frequently ignored disorders afflicting millions of Americans. More than 9 million women and 4 million men have undiagnosed thyroid problems.

Next Wednesday, people who want to learn more about thyroid disorders ranging from Graves disease to cancer can hear from doctors and patients at a national meeting of the Thyroid Foundation of America convening at the Baltimore Marriott Waterfront Hotel. Those interested in attending are asked to register in advance by calling 800-832-8321.

The 2 1/2 -hour program opens at 6:30 p.m. and will include a public forum where doctors and patients will discuss the disorders and field questions. Visitors can also arrange to speak privately with an expert about their problems and visit booths staffed by experts.

Dr. Lawrence C. Wood, president and medical director of the foundation, said people should consider attending if they or a family member has a thyroid-related condition. From staff and wire reports

MARIJUANA AND ARTERIES

Low doses of the main active ingredient in marijuana slowed the progression of hardening of the arteries in mice, suggesting a hint for developing a new therapy in people.

Experts stressed that the finding does not mean people should smoke marijuana in hopes of getting the same benefit.

"To extrapolate this to, `A joint a day will keep the doctor away,' I think is premature," said Dr. Peter Libby, chief of cardiovascular medicine at Boston's Brigham and Women's Hospital.

The mouse work was presented in yesterday's issue of the journal Nature by Dr. Francois Mach of Geneva University Hospital in Geneva, Switzerland, and colleagues. He said in an e-mail that he believed future work will focus on finding drugs that mimic the benefit without producing marijuana's effects on the brain.

Hardening of the arteries sets the stage for heart attacks. Inflammation plays a key role in the condition, characterized by a progressive buildup on the inside walls of blood vessels. So Mach and colleagues explored the anti-inflammatory effects of marijuana's main active ingredient, delta-9-tetrahydrocannabinol, or THC.

They fed mice a high-cholesterol diet for 11 weeks. About halfway through that period, they started giving some of the mice very low, daily oral doses of THC - too low to produce any marijuana-like changes in behavior. At the end of the experiment, mice that had gotten the THC showed less blood vessel clogging than did mice that got no THC.

Related work showed no additional benefit from higher THC doses, such as a person would get from smoking marijuana, Mach noted.

Researchers found that the benefit came from THC's effect on immune-system cells. It reduced their secretion of an inflammation-promoting substance and their migration to the vessel wall, researchers found.

It apparently did that by binding to proteins called CB2 receptors, which are found mostly on immune-system cells. THC also targets CB1 receptors, found mostly in the brain. So the work suggests scientists should try to develop a drug that works on CB2 receptors while ignoring the brain receptors, Mach said.

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