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  3. American Scientists Try to Develop Artificial Blood Vessel with the Skin Cell Scientists have grown blood vessels for kidney

American Scientists Try to Develop Artificial Blood Vessel with the Skin Cell Scientists have grown blood vessels for kidney

admin2013-07-08  90
问题         American Scientists Try to Develop Artificial Blood Vessel with the Skin Cell
    Scientists have grown blood vessels for kidney patients from their own cells, making it easier and safer for them to use dialysis machines, a new study says.
    Todd McAllister of Cytograft Tissue Engineering in California and colleagues implanted lab-grown blood vessels into 10 patients with advanced kidney disease in Argentina and Poland from 2004 to 2007.
    Early results for two of these patients were announced in 2005. In 2007, the scientists published preliminary findings for another 4 patients in the New England Journal of Medicine. In the most recent study, published in the medical journal Lancet, scientists reported on the new blood vessels in those same patients and 4 others.
    Dialysis patients need a vessel to connect them to dialysis machines. This can be made from their own vessels ~ But because dialysis is done so regularly, kidney patients often run out of healthy vessels and need an artificial one. Those are prone to infection.
    In the study, doctors took a small piece of skin from patients. Ceils from those samples were grown in a lab, to help them produce proteins. From those, scientists made sheets of tissue that were rolled into blood vessels 6 to 8 inches long. The vessels were finished after 6 to 9 months. All of the vessels were implanted into patients’ upper arms, to connect them to dialysis machines.
    The vessels failed in three of the patients, which experts said was not surprising in patients so seriously ill. One other patient withdrew from the study and another died of unrelated causes. In the five remaining patients, the vessels worked for at least 6 to 20 months after they were implanted. Afterwards, those patients needed fewer interventions, including surgeries, to maintain the vessels than regular dialysis patients.
    The study was paid for by Cytograft Tissue Engineering. McAllister said he and colleagues plan to test similar devices in patients with heart and leg problems.
    "It’s difficult to predict what will happen next, but they are on the right track." Vladimir Mironov of the Medical University of South Carolina said. But he worried the vessels, which cost between $ 15,000 and $ 20,000 might be too expensive to be used widely. Dr. Bryan Becker, president of the National Kidney Foundation in the US, said about haft of kidney patients could benefit from these vessels if further tests confirm they work.
The present vessels connecting patients to dialysis machines_____ .
选项 A、have caused a lot of cases of infection among patients
B、must be disposed after being used just once
C、axe either of a small quantity or of unsatisfactory quality
D、are too expensive for common patients to afford
答案C
解析 事实细节题。由题干中的vessels connecting patients to dialysis machines定位到第四段。由第三、四句可知，现在的连接通道，如果是使用病人的血管来培养，则数量不够；如果使用纯人造材料，则容易感染。故[C]“要么数量不够多，要么质量不够好”为正确答案。只有纯人造材料的连接管才容易导致感染，故排除[A]；文章没有说这些连接管是否是一次性的，故排除[B]；文章没有提到现在使用的连接管的价格，价格昂贵的是实验中的新型人造血管。故排除[D]。
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