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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

admin2012-11-11  102
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."
We can infer from Paragraph 3 that ______.
选项 A、ADAS cells are efficient in clinical application
B、ADAS cells act as naturally as marrow cells
C、ADAS cells can build bone formation orderly
D、ADAS cells therapy will replace genetic treatment
答案C
解析 这是一道推论题。题干中的信号词为Paragraph 3，也就是文章的第三段。文章第三段指出：隆加克的小组测试了ADAS细胞治疗头骨骨折的能力；在12个星期里，这些细胞填补了70%～90%的骨折部位，而未经治疗的老鼠只在不到10%的骨折部位无序地愈合；ADAS细胞起的作用同骨髓基质细胞一样好。由此可知，ADAS细胞可以有序地治愈骨折。C说“ADAS细胞可以有序地生长骨质”，这与文章的意思符合。文中说的是人体骨髓基质细胞已经被用于临床试验，并没有提到ADAS细胞用于临床实验，所以A不对；文中并没有说ADAS细胞是自然起作用，所以B不对；文中没有提到D。
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