VOA标准英语2012--Gene Therapy Halts Vision Loss in Dogs

Gene¹ Therapy Halts Vision Loss in Dogs

Researchers have stopped vision decline in dogs with an inherited disease that causes blindness.
The gene therapy technique they used may someday stop vision loss in humans.
Retinitis pigmentosa (RP) is an eye disease that causes the light-sensitive cells in the retina - the rods and cones² - to die.
The loss of eyesight normally happens slowly, over years or decades.
RP is caused by a genetic³ mutation⁴, so scientists at the University of Pennsylvania's Scheie Eye Institute and veterinary school teamed up to see if injecting a normal version of the mutant gene into dogs with the disease would stop the die-off of those light-sensitive cells.
"What we were able to show is that we can stop the degeneration, we can stop the cell death of both the rods and the cones," says University of Pennsylvania veterinary ophthalmologist William Beltran, the study's lead author. "What the gene therapy approach is doing is, in fact, rescuing those cells that are diseased but have not died yet."
Canine⁵ RP is like the human variety, which makes dogs a good model for studying the disease and possible treatments.
Beltran says the gene therapy appears to be safe and effective in stopping the progression of the disease, but he cautions that it can't do much to reverse vision loss. It can't restore the light-sensitive cells that have died, and it can't grow new ones.
Beltran says tests in humans are still an estimated four-to-five years off. He wants to do more animal testing to see, for example, if the gene therapy has a long-lasting effect.
"And the reason for doing so is that the likelihood is when we get to treat patients, we will be treating individuals that are at a rather later stage of degeneration."

1 gene   

n.遗传因子，基因

参考例句：

• A single gene may have many effects.单一基因可能具有很多种效应。
• The targeting of gene therapy has been paid close attention.其中基因治疗的靶向性是值得密切关注的问题之一。

2 cones   

n.（人眼）圆锥细胞；圆锥体( cone的名词复数 )；球果；圆锥形东西；（盛冰淇淋的）锥形蛋卷筒

参考例句：

• In the pines squirrels commonly chew off and drop entire cones. 松树上的松鼠通常咬掉和弄落整个球果。 来自辞典例句
• Many children would rather eat ice cream from cones than from dishes. 许多小孩喜欢吃蛋卷冰淇淋胜过盘装冰淇淋。 来自辞典例句

3 genetic   

adj.遗传的，遗传学的

参考例句：

• It's very difficult to treat genetic diseases.遗传性疾病治疗起来很困难。
• Each daughter cell can receive a full complement of the genetic information.每个子细胞可以收到遗传信息的一个完全补偿物。

4 mutation   

n.变化，变异，转变

参考例句：

• People who have this mutation need less sleep than others.有这种突变的人需要的睡眠比其他人少。
• So far the discussion has centered entirely around mutation in the strict sense.到目前为止，严格来讲，讨论完全集中于围绕突变问题上。

5 canine   

adj.犬的，犬科的

参考例句：

• The fox is a canine animal.狐狸是犬科动物。
• Herbivorous animals have very small canine teeth,or none.食草动物的犬牙很小或者没有。