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阅读模拟题（8）
At 18, Ashanthi DeSilva of suburban Cleveland is a living symbol of one of
the great intellectual achievements of the 20th century. Born with an extremely
rare and usually fatal disorder that left her without a functioning immune
system (the "bubble-boy disease", named after an earlier victim who was kept
alive for years in a sterile plastic tent), she was treated beginning in 1990
with a revolutionary new therapy that sought to correct the defect at its very
source, in the genes of her white blood cells. It worked. Although her last
gene-therapy treatment was in 1992, she is completely healthy with normal immune
function, according to one of the doctors who treated her, W. French Anderson of
the University of Southern California. Researchers have long dreamed of treating
diseases from hemophilia to cancer by replacing mutant genes with normal ones.
And the dreaming may continue for decades more. "There will be a gene-based
treatment for essentially every disease," Anderson says, "within 50 years."
It's not entirely clear why medicine has been so slow to build on
Anderson's early success. The National Institutes of Health budget office
estimates it will spend $432 million on gene-therapy research in 2005, and there
is no shortage of promising leads. The therapeutic genes are usually delivered
through viruses that don't cause human disease. "The virus is sort of like a
Trojan horse," says Ronald Crystal of New York Presbyterian/Weill Cornell
Medical College. "The cargo is the gene."
At the University of Pennsylvania's Abramson Cancer Center, immunologist
Carl June recently treated HIV patients with a gene intended to help their cells
resist the infection. At Cornell University, researchers are pursuing gene-based
therapies for Parkinson's disease and a rare hereditary disorder that destroys
children's brain cells. At Stanford University and the Children's Hospital of
Philadelphia, researchers are trying to figure out how to help patients with
hemophilia who today must inject themselves with expensive clotting drugs for
life. Animal experiments have shown great promise.
But somehow, things get lost in the translation from laboratory to patient.
In human trials of the hemophilia treatment, patients show a response at first,
but it fades over time. And the field has still not recovered from the setback
it suffered in 1999, when Jesse Gelsinger, an 18-year-old with a rare metabolic
disorder, died after receiving an experimental gene therapy at the University of
Pennsylvania. Some experts worry that the field will be tarnished further if the
next people to benefit are not patients but athletes seeking an edge. This
summer, researchers at the Salk Institute in San Diego said they had created a
"marathon mouse" by implanting a gene that enhances running ability; already,
officials at the World Anti-Doping Agency are preparing to test athletes for
signs of "gene doping". But the principle is the same, whether you're trying to
help a healthy runner run faster or allow a muscular-dystrophy patient to walk.
"Everybody recognizes that gene therapy is a very good idea," says Crystal. "And
eventually it's going to work."
1. The case of Ashanthi Desilva is mentioned in the text to
____________.
[A] show the promise of gene-therapy
[B] give an example of modern treatment for fatal diseases
[C] introduce the achievement of Anderson and his team
[D] explain how gene-based treatment works
2. Anderson‘s early success has ________________.
[A] greatly speeded the development of medicine
[B] brought no immediate progress in the research of gene-therapy
[C] promised a cure to every disease
[D] made him a national hero
3. Which of the following is true according to the text?
[A] Ashanthi needs to receive gene-therapy treatment constantly.
[B] Despite the huge funding， gene researches have shown few promises.
[C] Therapeutic genes are carried by harmless viruses.
[D] Gene-doping is encouraged by world agencies to help athletes get better
scores.
4. The word “tarnish” (line 5， paragraph 4) most probably means
____________.
[A] affect
[B] warn
[C] trouble
[D] stain
5. From the text we can see that the author seems ___________.
[A] optimistic
[B] pessimistic
[C] troubled
[D] uncertain
答案：A B C D A |
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发表于 2018-8-18 14:25:40