Serotonin is a major signaling chemical in the brain, and it has long been thought to be involved in aggressive behavior in a wide variety of animals as well as in humans. Another brain chemical signal, neuropeptide Y (known as neuropeptide F in invertebrates), is also known to affect an array of behaviors in many species, including territoriality in mice. A new study by Drs. Herman Dierick and Ralph Greenspan of The Neurosciences Institute in San Diego shows that these two chemicals also regulate aggression in the fruit fly, Drosophila melanogaster.

A new study says targeting smaller (¡Ü5 mm) lesions does little to significantly reduce the incidence of colorectal cancer (CRC) and, in fact, results in extremely high financial costs and a large proportion of adverse events. Published in the June 1, 2007 issue of CANCER, a peer-reviewed journal of the American Cancer Society, a cost-benefit analysis study says the low malignancy rate among so-called diminutive polyps gives virtual colonoscopy with removal of lesions 6 mm or greater the best estimated value per life year gained and with fewer complications.

Mayo Clinic researchers, along with collaborators from the National Institutes of Health (NIH) and University of Oslo, Norway, have discovered that a miscue of the body’s genetic repair system may cause Huntington’s disease, a fatal condition that affects 30,000 Americans annually by destroying their nervous system. Until now, no one knew how Huntington’s begins, only that it is incurable. The findings appear in the online issue of the journal Nature.

The most recent census of mountain gorillas in Uganda’s Bwindi Impenetrable National Park—one of only two places in the world where the rare gorillas exist—has found that the population has increased by 6 percent since the last census in 2002, according to the Uganda Wildlife Authority, the Wildlife Conservation Society, the Max Planck Institute of Anthropology and other groups that participated in the effort.

Adolescents who are chronically exposed to family turmoil, violence, noise, poor housing or other chronic risk factors show more stress-induced physiological strain on their organs and tissues than other young people.

However, when they have responsive, supportive mothers, they do not experience these negative physiological changes, reports a new study from Cornell.

Runners in today's London Marathon may be tempted to down several litres of water to keep their cool and achieve their best time, but large fluid intake does not achieve either, according to a sports scientist from the University of Exeter.

With today's temperatures expected to reach 19 degrees, the average runner will potentially lose almost a litre of sweat every hour and reach a body temperature of over 39 degrees, two degrees above normal. The sporting community has long assumed that drinking large amounts of water helps to keep the body's temperature down, which improves performance. A recent study led by Dr Chris Byrne of the University of Exeter shows that the level of fluid intake has absolutely no effect on body temperature or performance.