Sound Medicine -- March 15, 2003

Hosts Barbara Lewis and Dr. Kathy Miller talk to physicians & researchers about:

Pain and the brain

The "Brain" exhibit at the State Museum

Teeth whiteners

Pain and the brain

The brain controls the pathways and chemicals that produce pain, and thanks to medical research today we understand much about pain relief. But brain researchers are still exploring new ways for relieving pain, especially chronic pain. We hear more from Michael Vasko, MD, professor of pharmacology at the Indiana University School of Medicine.

Nerves in our skin and organs communicate signals from the body to the brain. Some nerves (also called sensory neurons) carry touch signals, but others carry sensations, some of them noxious, like pain. When activated, the nerves conduct the signal to the spinal cord, to the brain, and to the center of the brain, which perceives it as bad. The brain then causes us to register a response -- to cry out or pull away.

Dr. Vasko discusses nerve stimuli, body chemicals called prostaglandins, and the basic mechanism that causes many pain medications, including new ones like COX-2 inhibitors (i.e. Celebrex) to work. Although it's unclear why people perceive pain and respond to drugs differently, Dr. Vasko explains how new techniques in brain imaging can help researchers understand how pain signals travel through the somatosensory cortex.

Of especial interest to Dr. Vasko is chronic pain, which modern drugs do not treat well. We often don't even know what causes chronic pain, he says, since often the injury itself is gone. It's a "neuropathic pain," a pathology of the nerves. One syndrome is "central pain," a lesion in the brain; another is "phantom limb" pain. Imaging techniques might help solve the riddle, perhaps by revealing ways we can train the brain to adapt. Dr. Vasko talks about current, holistic treatments for chronic pain. He also explains how gene therapy may help reduce people's sensitivity to pain.

Resources:

Dr. Vasko lectures on this topic at the IU School of Medicine's Mini Medical School on Tuesday, March 18.

The MEDLINEplus service provides excellent links on pain and pain research.

Read more about chronic pain and a recent study on chronic pain from the National Institute of Neurological Disorders and Stroke.

Writer Reynolds Price's book, A Whole New Life, is a thoughtful and popular autobiography addressing the topic of living with chronic pain. Read excerpts at Amazon.com.

The "Brain" exhibit at the State museum

Through May 4, the Indiana State Museum in White River State Park hosts a traveling exhibition called "Brain: The World Inside Your Head." Alicia Stewart, programs coordinator for the museum, discusses the 5,000 square foot interactive exhibit that aims to demystify the brain's functions -- and malfunctions. She says kids are fascinated by the real brain on display.("Is it real?" they want to know.) Kids also enjoy the displays showing how the brain plays tricks on you and how the its neurotransmitters crack and pop. The exhibit was created by Pfizer, Inc. to promote brain health and the understanding of brain disease.

Resources:

Visit the Indiana State Museum Web site for hours and prices.

Pfizer Inc. provides more details on the exhibit and its outreach efforts promoting brain health and understanding.

Teeth whiteners

Like tanning, teeth whitening is a popular cosmetic treatment. Dr. Greg Raymond from the Center for Cosmetic Dentistry in Indianapolis discusses various procedures and their safety. As well as simple aging, causes of tooth discoloration include taking tetracycline as a small child (which darkens and bands tooth bud enamel), and drinking coffee, tea, cola, and red wine. Tobacco also stains teeth.

Dr. Raymond explains that the procedures used today are all FDA approved and that the same basic chemistry has been in use for the past 20 years.

The most expensive treatment is laser whitening. It requires special equipment and must be performed by a dentist. The lights penetrate below the surface of the teeth to whiten. The most common side effect to laser whitening, or to any whitening treatment says Dr. Raymond, is tooth and gum sensitivity. Sensitivity can be minimized by reducing the number and strength of treatments. The most popular in-office treatment is to be fitted with a mouthpiece"tray" that holds a bleaching solution, typically peroxide. People wear the tray twice a day for 15 or 20 minutes. As for over-the-counter products, Dr. Raymond's believes they are either too abrasive or too weak. He also also discusses two other whitening treatments: porcelain veneers and bonding.

Resources:

American Dental Association answers a list of frequently asked questions and provides video footage on teeth whitening procedures.

The Forsyth Institute conducts clinical studies on teeth whitening procedures, among other things. Read about a study currently underway comparing four different procedures.

Is there a medical topic you'd like us to cover? Reach us by email: soundmed@iu.edu
or by phone:
(317) 274-4848.

Since the introduction of wireless phones, researchers have debated whether the energy they emit causes cancer. It has been claimed that as much as 60 percent of the microwave radiation emitted while using a wireless phone is absorbed into the head, some reaching an inch to an inch-and-a-half into the brain. Are wireless phones really are harmful to your health?

Find out!

Two clinical studies published in the March 6 edition of the New England Journal of Medicine looked at the effect of aspirin in reducing the risk of colon cancer, the second leading cause of cancer-related death in the U.S.

In a 31-month study of colon cancer survivors, researchers gave patients either a regular dose (325 milligrams) of aspirin or a placebo daily. The second study, carried out over a seven-year period, gave individuals who had precancerous polyps removed either a regular dose of aspirin or a low dose (81 milligrams) daily.

Of the colon cancer survivors, those receiving aspirin had a 35% reduction in their risk for new polyps compared to the placebo group. Of the precancerous polyps patients, those receiving the smallest aspirin dose had the biggest reduction in colon cancer risk -- 19% reduction for developing any polyp and 40% reduction for developing advanced polyps.

Get details about the studies in MEDLINE news.

Nevertheless, gastroenterologist Thomas F. Imperiale, MD, professor of medicine at the Indiana University School of Medicine commented on these studies in the same issue of the journal. He writes that the moderate benefits of aspirin do not outweigh the risks of gastrointestinal bleeding, intracranial hemorrhage and peptic ulcers associated with long-term aspirin use.

In addition he says, "The studies indicate that aspirin can work by moderately reducing the risk of recurrent polyps but larger and longer-term trials are needed to determine whether aspirin can reduce the frequency or intensity of screening exams."

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