Archive for December 2010
Dopamine is a neurotransmitter that seems to have been around from about the time of the very first nerves. Every animal we’ve looked at, including some that branched off prior to the Cambrian, seems to express the dopamine signaling machinery in its nerves. So you might expect that eliminating dopamine entirely would be a fatal step. But, at least when it comes to everyone’s favorite fruit fly, Drosophila melanogaster, that’s not the case. Flies that apparently lack dopamine signaling manage to live just as long as their peers. They do, however, end up turning into lethargic masochists.
Toxoplasmosis is a serious disease when transmitted from a pregnant mother to the unborn fetus, potentially resulting in stillbirth, brain damage, or long-term eye damage that can lead to blindness. Even worse, it’s extremely common in a most common animal, the house cat—and it’s easily transmissible from cats to humans. The parasite that causes it, Toxoplasma gondii, is found in one-third to one-half of all humans—over two billion individuals! This potential killer likes to take up residence inside your brain.
When cells are exposed to life-threatening stresses, they take quick action to save themselves. Among other defenses, they start manufacturing proteins that perform critical tasks such as repairing DNA.
Researchers at MIT and the University of Albany have now discovered one way that cells boost production of such proteins. In the Dec. 16 issue of PLoS Genetics, they report that when under stress, cells reprogram a complicated system of chemical modifications of the RNA molecules that read the genetic code and deliver protein building blocks.
Women with metastatic breast cancer who have no tumor cells circulating in their blood after the first round of treatment live longer than those who do, French researchers report.Circulating tumor cells, or CTCs, are cells that break off from a tumor and escape into the bloodstream. These cells can travel to other organs and establish new tumors.
Several studies have shown that higher levels of CTCs are associated with an increased risk for recurrence and death in metastatic breast cancer patients.But the new study is the largest to look at the topic, and the CTCs predicted prognosis even after taking other markers of survival into account, says Jean-Yves Pierga, MD, PhD, professor of the medical oncology department at Institut Curie and Universite Paris Descartes, France.