For years, scientists have known that drug-carrying nanoparticles could provide new, potent treatments for diseases like cancer by sending them to targeted parts of the body. But there was one big problem: Before the particles could make it to their intended location, the patients' immune systems would kill them off. Now a team of California-based researchers has figured out a way to disguise the particles to look like parts of blood cells, according to an article published today in Nature.
Wanting to know the secrets of her longevity, scientists have examined her blood and other tissues, and found some interesting things. For one, they found that about two-thirds of her white blood cells had been made by only two stem cells. (Stem cells create white blood cells, which are responsible for fighting off infection, and other functions.) Typically, about 1,000 stem cells actively make these blood cells. That finding implies that, predictably, stem cells die out throughout the years, and that there is indeed a limit to human life. But it also means that it may be possible to save stem cells from one's birth or youth, keep them alive outside the body, and re-inject them years later, to lengthen life.
