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  3. For the first time, stem cells purified from fat have been used to heal an injury in a living animal. Michael Longaker of Stanfo

For the first time, stem cells purified from fat have been used to heal an injury in a living animal. Michael Longaker of Stanfo

admin2014-02-27  72
问题     For the first time, stem cells purified from fat have been used to heal an injury in a living animal. Michael Longaker of Stanford University in California and his team showed in mouse experiments that so-called adipose derived adult stromal(ADAS)cells purified from a rodent’s belly fat could be coaxed to heal a skull fracture too large to mend by itself.
    The power of ADAS cells to transform into bone, cartilage and even neurons has been studied for years in test tubes. But Jeffrey Gimble, who studies human ADAS cells at Louisiana State University in Baton Rouge says Longaker’s report is an important step forward. "Actually repairing a defect in an animal model had never been done. This is an excellent study." If the same technique works in humans, these cells could be coaxed to mend broken bones and correct other defects in tens of thousands of surgical procedures each year in which bone grafts and prosthetics are now necessary.
    Longaker’s group tested the ability of ADAS cells to heal four-millimetre-long fractures surgically-induced in the skulls of mice. In 12 weeks, the cells filled 70 to 90 per cent of the defects, while untreated animals had only unorganized bone formation in less than 10 per cent of the fractures. No extreme genetic manipulation or treatment of the cells was necessary. ADAS cells began manufacturing bone when they were simply laid onto a biodegradable polymer that contained apatite, a compound that naturally occurs in bone. Furthermore, the ADAS cells performed as well as bone marrow stromal cells, which would seem to be more natural architects of bone. It remains to be seen whether human ADAS cells will build bone as effectively. But researchers are excited about the prospects. Human bone marrow stromal cells are already being used in clinical trials as sources of skeleton-building material, but the ADAS cells may have some significant advantages.
    Longaker reports that ADAS cells grow seven times faster than the bone marrow cells in the laboratory. And it is relatively easy to harvest more than a litre of fat tissue, even from patients who are not obese. Bone marrow is much less plentiful and must be removed in a painful surgical procedure. Of course, liposuction itself is not a pleasant operation. But according to the American Society of Plastic Surgeons, more than 300,000 people volunteered to have the procedure in 2003 simply for cosmetic reasons. "If the procedure was the first step to healing broken bones or replacing other tissue its popularity could only grow," says Gimble. "Just think of that."
As to ADAS cells, which of the following is NOT localized in laboratory?
选项 A、They are easy to operate.
B、Their abstraction causes no pains.
C、They grow fast.
D、Their yields are large.
答案B
解析 这是一道细节题。文章最后一段指出：ADAS细胞的生长速度比实验室里骨髓细胞快7倍，而且也相对容易收集，即使是从不肥胖的病人身上收集也不难。这说明，ADAS细胞可以在实验室之外提取。B说“提取ADAS细胞不会引起疼痛”，这与文章的意思符合。文中说的是不需要对这些细胞进行过度的基因控制或处理，并不是说容易控制，所以A不对：文章最后一段是说ADAS细胞的生长速度比实验室里骨髓细胞快7倍，并没有说它们是在何处生长的，所以C不对；文中没有提到D。
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