RESEARCH BRIEFS

Drug Activated by Laser May Fight Cancer

Massachusetts General Hospital (MGH) researchers are studying a new cancer-fighting drug, BDP-MA, which is activated by shining a laser on patients who have taken it.

The drug has already been shown to be effective in treating animal tumors. Doctors at MGH are currently studying its effects on humans under the direction of Harvard Medical School Associate Professor of Dermatology Dr. R. Rox Anderson.

BDP-MA is a "second generation" drug. The earlier version of the drug, Photofrin II, has been used experimentally in humans for several years. Both have yet to receive U.S. Food and Drug Administration approval for regular use.

BDP-MA's advantage over Photofrin II, say researchers, is that it causes significantly less photosensitivity in patients without losing effectiveness. While patients treated with Photofrin II often suffer first and second degree burns after only a few minutes of exposure to sunlight, so far BDP-MA has not been shown to have such side effects.

The light activation which is possible with BDP-MA, as with its predecessor, enables doctors to increase the effectiveness and the specificity of the treatment. Lasers make it possible to treat cancer-affected organs which are not directly accessible to normal light. Due to their high intensity, lasers also reduce necessary exposure times.

Doctors Discover Key Growth Factor in Ulcer Therapy

Ulcer repair research at Harvard Medical School has revealed an important growth factor which may improve current therapies for the condition.

Led by Dr. M. Judah Folkman, Andrus professor of pediatric surgery and a professor of anatomy and cellular biology at the Medical School, a team of doctors discovered that basic fibroblast growth factor (bFGF) is present in the normal lining of the intestines and in ulcerated tissue. The team also found evidence that the growth factor may be critical in duodenal ulcer repair.

The researchers investigated the role that angiogensis, or the growth and proliferation of blood vessels, plays in the healing of wounds such as stomach ulcers. It was reported ten years ago that bFGF promotes such growth and proliferation.

Angiogenesis may play an important role in ulcer repair because a key step in the repair of any wound is the development of granular tissue, rich in small blood vessels. Researchers were interested in determining whether bFGF could be used to stimulate angiogensis and thereby promote the healing of stomach ulcers.

The doctors also found that bFGF accelerated healing in rats without reducing levels of gastric acid in the stomach. The mechanism for this action was discovered in studies which showed that bFGF binds to sucralfate, a drug used to treat ulcers, and is protected from breakdown by stomach acid.

Psychiatrist Finds Dream-Promoting Neurochemical

A chemical that increases dreaming sleep by up to 300 percent may be important evidence for a Medical School professor's conclusion that many of the psychological features of dreaming are caused by biochemical activity in the brain.

Professor of Psychiatry Dr. J. Allan Hobson has found a chemical, called carbachol, which imitates the action of a dream-promoting neurochemical, acetylcholine.

By injecting this substance into the brain stems of cats, Hobson was able to increase rapid eye movement (REM) activity dramatically. The study also demonstrated that the chemical prompts nerve cells to broadcast secondary chemical messages to vision-processing areas of the brain.

While Hobson says that the brain functions differently while asleep than while awake, the purpose of sleep for the brain is not rest. Instead, the sleeping brain is probably concerned with protein manufacture, he says.