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  3. For several years, scientists have been testing a substance called interfero

For several years, scientists have been testing a substance called interfero

游客2025-03-21  53
问题     For several years, scientists have been testing a substance called interferon, a potential wonder drug that is proving to be effective in treating a variety of ailments, including virus infections, bacteria infections, and tumors. To date, the new drug has provoked no negative reaction of sufficient significance to discourage its use. But in spite of its success, last year only one gram was produced in the entire world.
    The reason for the scarcity lies in the structure of interferon. A species specific protein, the interferon produced from one animal species cannot be used in treating another animal species. In other words, to treat human beings, only interferon produced by human beings may be used. The drug is produced by infecting white blood cells with a virus. Fortunately, it is so potent that the amount given each patient per injection is very small.
    Unlike antibiotics, interferon does not attack germs directly. Instead, it makes unaffected cells resistant to infection, and prevents the multiplication of viruses within cells.
    As you might conclude, one of the most dramatic uses of interferon has been in the treatment of cancer. Dr. Hans Strander, research physician at Sweden’s famous Karohnska Institute, has treated more than one hundred cancer patients with the new drug. Among a group of selected patients who had undergone surgical procedures for advanced cancer, half were given conventional treatments and the other half were given interferon. The survival rate over a three-year period was 70 percent among those who were treated with interferon as compared with only 10 to 30 percent among those who had received the conventional treatments.
    In the United States, a large-scale project supported by the American Cancer Society is now underway. If the experiment is successful, interferon could become one of the greatest medical discoveries of our time. [br] Which of the following statements is the results of Dr. Strander’s experiments with interferon?
选项 A、Half of the patients who received interferon reacted favorably.
B、At the end of three years, all of the patients who had not received interferon had died.
C、Most of the patients who received interferon also needed conventional treatments.
D、70 percent among patients who were treated with interferon survived.
答案 D
解析 文中第四段最后一句说：“与那些接受常规治疗的癌症病人相比，在接受干扰素治疗的癌症病人中生存期超过三年的比率是70％，而接受常规治疗的癌症病人的生存比率仅为10%至30％。”由此可知，选项D正确。
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