Cancer fighter reveals a dark side. (Biomedicine).Too much of a good thing can be bad, even when it comes to a tumor-suppressing gene. Researchers report that mice with an overactive o·ver·ac·tive adj. Active to an excessive or abnormal degree: an overactive child. o gene for a protein called p53, which checks inappropriate cell division and helps prevent cancer, prematurely suffer age-related conditions such as osteoporosis and die earlier than normal. This raises the prospect that there's a tradeoff between tumor suppression and a long lifespan. Lawrence A. Donehower of the Baylor College of Medicine Baylor College of Medicine is a private medical school located in Houston, Texas, USA on the grounds of the Texas Medical Center. It has been consistently rated the top medical school in Texas and among the best in the United States. in Houston and his colleagues were trying to produce mice with a disabled p53 gene when they accidentally created a mouse strain in which the gene is overactive. Mice lacking the p53 gene are cancer-prone, so it isn't surprising that the new mutant strain is much less likely than normal to develop tumors. Despite the enhanced cancer protection, the mutant mice die earlier than normal. The median lifespan of the mutant mice is 96 weeks, whereas normal mice have a median lifespan of 118 weeks, Donehower's team reports in the Jan. 3 NATURE. The researchers couldn't find any common cause of death in the mutant mice, so they wondered whether the animals suffer from accelerated aging Accelerated aging is a testing method used to estimate the useful lifespan of a product when actual lifespan data is unavailable. This occurs with products that have not existed long enough to have gone through their useful lifespan: for example, a new type of car engine or a new . Further investigation proved that hunch hunch n. 1. An intuitive feeling or a premonition: had a hunch that he would lose. 2. A hump. 3. A lump or chunk: "She . . . to be right, revealing that these mice develop osteoporosis, impaired wound healing wound healing Physiology The repair of a wound Steps Inflammation, repair and closure, remodeling, final healing; repair of incisions may be either simple–'clean' wounds with little loss of tissue heal by 'primary intention', or 'dirty' wounds heal by , muscle weakening, organ atrophy, and other age-related conditions much earlier in their lives than rodents normally do. The mutant mice didn't age faster in all ways, however. For cataracts Cataracts Definition A cataract is a cloudiness or opacity in the normally transparent crystalline lens of the eye. This cloudiness can cause a decrease in vision and may lead to eventual blindness. , joint diseases, and hair loss were not more in the mutant mice than in normal mice of the same age. Donehower and his colleagues speculate that the conditions seen in the mutant mice result from a p53-mediated reduction in the ability of unspecialized cells to proliferate and keep tissues healthy. The results "raise the shocking possibility that aging may be a side effect of the natural safeguards that protect us from cancer," Gerardo Ferbeyre of the University of Montreal Of Montreal is an American indie pop band formed in Athens, Georgia, fronted by Kevin Barnes. It was among the second wave of groups to emerge from The Elephant 6 Recording Company. and Scott W. Lowe of Cold Spring Harbor (N.Y.) Laboratory in a commentary accompanying the research report. --J.T. |
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