radiation
Scientists at St. Jude Children's Research Hospital have discovered a novel biochemical process that plays a critical role in helping cells in the body respond to DNA damage, such as that caused by exposure to radiation, environmental toxins or free radicals. The findings could lead to new approaches to prevent cancer, better ways to treat cancer and to the development of sensitive methods determining whether people have been exposed to radiation or environmental toxins, according to the researchers.
A team of scientists has shrunk tumors or delayed their growth in animal studies by using radiation to enable a drug to "zero in" and block the tumor blood vessels. The work, reported in the January issue of the journal Cancer Cell, is a model for what might be achieved in patients by using radiation to activate drug targets in tumors. "We can now use combinations of chemotherapy and radiation to improve the anti-cancer effect for many of our patients, but the side effects can be great," said Dr. Dennis Hallahan, chair of Radiation Oncology at Vanderbilt- Ingram. "With this approach, we hope we can ultimately deliver drugs directly and selectively to the tumor alone, and reduce side effects."
A dramatic increase in deformed frogs and other amphibians is being caused by a range of environmental factors, all of which can ultimately be linked to human impacts on habitat, but the primary cause of many of the deformities is an epidemic of a key parasite. These findings are the results of eight years of research by scientists around the world, and are presented in the February issue of Scientific American by researchers from Oregon State University and the University of Wisconsin.
Despite advances in neurosurgery and radiation techniques, the prognosis for patients with intracranial glioma remains devastating. Now, researchers have identified a possible new treatment strategy for this common type of malignant brain tumor. Two studies funded in part by the National Institute of Neurological Disorders and Stroke (NINDS) show that, in a mouse model, neural stem cells (NSCs) can be used to deliver therapeutic agents capable of killing glioma cells and their migrating tumor cells.
The federal government today published its biennial Report on Carcinogens, adding steroidal estrogens used in estrogen replacement therapy and oral contraceptives to its official list of "known" human carcinogens. This and 15 other new listings bring the total of substances in the report, "known" or "reasonably anticipated" to pose a cancer risk, to 228. Among the other new additions: wood dust and ultraviolet light.
Physicians treating deadly liver tumors are finding success by injecting patients with radioactive microspheres that get trapped in the web of small blood vessels feeding a tumor and zap the cancerous cells. "The liver doesn't tolerate external beam radiation in sufficient doses to affect tumor without damaging the remaining good liver," said one physician researcher working on the treatment. "These spheres emit radiation for a short distance, less than a centimeter. If you can cluster radiation right around the tumor, the radiation exposure at the tumor site compared to normal liver is favorable."
In a 20-year follow-up study of mortality data on residents living within a five-mile radius of Three Mile Island (TMI), researchers at the University of Pittsburgh's Graduate School of Public Health (GSPH) found no significant increase overall in deaths from cancer. "This survey of data, which covers the normal latency period for most cancers, confirms our earlier analysis that radioactivity released during the nuclear accident at TMI does not appear to have caused an overall increase in cancer deaths among residents of that area over the follow-up period, l979 to l998," said Evelyn Talbott, Dr.P.H., professor of epidemiology at GSPH and principal investigator on the study.
Researchers in Britain have developed a drug they say could revolutionize the effectiveness of radiation on cancer. Radiotherapy is used to destroy cancer cells by zapping their DNA, thus disrupting their ability to function and reproduce. But like other cells in the body, cancer cells have a sort of DNA repair kit that can minimize these effects. The new drug disables the DNA repair process and allows radiotherapy to target tumors with "deadly accuracy."
A tough microbe called Deinococcus radiodurans can withstand blasts of radiation, enduring several thousand times the lethal dose for humans. How did these little bugs develop this resistance? A team of Russian scientists has concluded that these extraordinary organisms are actually Martian microbes, here on Earth by way of meteorites. In tests on common bacteria E. coli, the scientists determined that evolution of radiation-resistance would take longer than 3.8 billion years, the time that life has been on Earth. In contrast, the bugs could develop this characteristic on the Red Planet in only a few hundred thousand years. On Mars there are much higher levels of radiation and the planet experiences regular climate swings that would induce dormancy in microbes, allowing them to accumulate sufficient doses of radiation to evolve into radiation-resistant critters.
See also: Acidic clouds of Venus could harbour life
