A group of researchers led by Patrick Yu-Wai-Mjye.ai.jye.ai ophthalmologist （眼科醫(yī)師） at Cambridge University，investigated a new genetic therapy for a form of blindness.Officially，their study was a failure.But it was also a great success，for 29 of the 37 participants reported big improvements in their vision.
The disease in question is Leber Hereditary Optic Neuropathy （LHON）（遺傳性視神經(jīng)病變） .A defective gene leads to sudden and rapid loss of sight，with many sufferers becoming legally blind within a year.It affects between one in 30，000 and one in 50，000 people.Men in their 20s and 30s are particularly at high risk.Since most cases are caused by a mutation （突變） in a single gene，LHON is a good candidate for gene therapy，a form of genetic engineering which aims to replace the defective gene with a working one.
With that in mind.Dr Yu-Wai-Man and his colleagues loaded up a changed virus with a corrected copy of the gene and injected it into their patients' eyes.The researchers controlled the experiment by injecting only one of each patient's eyes--chosen at random--with the virus.The other eye was given a fake injection.Using two eyes in the same patient makes for a perfect control.
The surprise came several months later.The researchers had hoped to see a big improvement in the treated eyes，compared with the untreated ones.They did not，for which the study failed in its primary objective.Instead，in more than three quarters of their patients，they saw significant improvements in both eyes.
On the face of it，that was odd.Only one eye had received the treatment，after all.Follow-up studies in monkeys confirmed what the researchers had suspected.The virus，it seemed，had found a way to travel from one eye to the other，probably via the optic nerve.Tissues and fluids samples from monkeys given the same treatment as the human patients showed viral DNA in both eyes，not just one.
Although it had a happy outcome in this case，the prospect of a gene-therapy virus travelling to places it is not intended to go to might worry regulators.Fortunately，the researchers found no trace of the virus elsewhere in the monkeys' bodies.And.jye.ai the study was technically a failure，its practical success means that an effective treatment for LHON may at last be in reach.
（1）LHON is chosen in this study because it DD
A．can be easily cured
B．a(chǎn)ffects young males mostly
C．is a common disease among people
D．results from a mutation in a single gene
（2）Why was the study a great success despite a failure officially？ BB
A．Some participants suffered loss of sight
B．The vision of both eyes improved greatly
C．All the participants gave positive feedback
D．The virus didn't replace the damaged gene
（3）The experiment on monkeys is mentioned in order to AA
A．confirm the virus travels across eyes
B．prove the virus can affect other body parts
C．show the effect of the treatment on animals
D．highlight regulators' worry about gene-therapy
（4）Which is the best title for the passage？ CC
A．The Future of Gene Therapy
B．The Blessing for Eye Patients
C．Gene Therapy：Eyeball to Eyeball
D．Virus Treatment：From Humans to Monkeys
【答案】D；B；A；C
【解答】
【點評】
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發(fā)布：2024/7/11 8:0:9組卷：1引用：1難度：0.5
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