VOA标准英语2012--Drug Reverses Alzheimer's in Lab Mice

Drug Reverses Alzheimer's in Lab Mice

Researchers working with laboratory mice have stopped the progression of a condition found in the brain of Alzheimer's victims.
They've even reversed cognitive¹ decline. But whether the discovery can translate to a treatment for humans with Alzheimer's is still a very big question
In Alzheimer's patients, a substance called beta amyloid builds up, and it's deposited as plaques² on brain cells.
It's not that the body is producing too much beta amyloid. "The problem is in Alzheimer's disease, due to age-related inefficiencies in the ability to cut this peptide up and dispose of it, the peptide accumulates in the brain," explains Case Western Reserve University researcher Gary Landreth.
Clearing away beta amyloid is facilitated by a brain protein called apolipoprotein E (ApoE). An established anti-cancer drug bexarotene indirectly³ helps turn on the ApoE gene⁴.
"So what this drug does is, it facilitates the normal clearing of the amyloid peptide. But then it also induces the brain's immune cells, or microglia, to eat up and dispose of the amyloid plaques, and the net effect is to clear amyloid from the brain."
Landreth tested the drug on mice that were genetically⁵ engineered to have an Alzheimer's-like condition. The mice that got the bexarotene drug regained⁶ some of the skills and behaviors lost to Alzheimer's. For example, normal mice shred⁷ up paper to build nests. But the untreated Alzheimer's mice don't. However, "if we put these guys on [the] drug for just 72 hours, they begin to build nests again. So...what the mice suggest is that in early stages of Alzheimer's Disease, the disease appears to be reversible."
Landreth cautions that what works in mice may not work at all in people, and that the mice in the study had the equivalent of early stage Alzheimer's, so that any reversal of Alzheimer's symptoms may not occur in more advanced cases.
Landreth and a colleague have applied⁸ for a patent to use bexarotene for Alzheimer's, and he doesn't hide his enthusiasm.
"This is kind of like being struck by lightning," he said. "We have a drug that is very safe, and importantly, it gets across the blood-brain barrier. That is, we can get it into the brain. And this is very rare."
Preliminary clinical trials in humans could begin in just a few weeks.
The research paper by Gary Landreth of the Case Western Reserve University School of Medicine in Cleveland, Ohio, and his colleagues is published online in Science.

1 cognitive   

adj.认知的，认识的，有感知的

参考例句：

• As children grow older,their cognitive processes become sharper.孩子们越长越大，他们的认知过程变得更为敏锐。
• The cognitive psychologist is like the tinker who wants to know how a clock works.认知心理学者倒很像一个需要通晓钟表如何运转的钟表修理匠。

2 plaques   

（纪念性的）匾牌( plaque的名词复数 )； 纪念匾； 牙斑； 空斑

参考例句：

• Primary plaques were detectable in 16 to 20 hours. 在16到20小时内可查出原发溶斑。
• The gondoliers wore green and white livery and silver plaques on their chests. 船夫们穿着白绿两色的制服，胸前别着银质徽章。

3 indirectly   

adv.间接地，不直接了当地

参考例句：

• I heard the news indirectly.这消息我是间接听来的。
• They were approached indirectly through an intermediary.通过一位中间人，他们进行了间接接触。

4 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。

5 genetically   

adv.遗传上

参考例句：

• All the bees in the colony are genetically related. 同一群体的蜜蜂都有亲缘关系。
• Genetically modified foods have already arrived on American dinner tables. 经基因改造加工过的食物已端上了美国人的餐桌。 来自英汉非文学 - 生命科学 - 基因与食物

6 regained   

复得( regain的过去式和过去分词 )； 赢回； 重回； 复至某地

参考例句：

• The majority of the people in the world have regained their liberty. 世界上大多数人已重获自由。
• She hesitated briefly but quickly regained her poise. 她犹豫片刻，但很快恢复了镇静。

7 shred   

v.撕成碎片，变成碎片；n.碎布条，细片，些少

参考例句：

• There is not a shred of truth in what he says.他说的全是骗人的鬼话。
• The food processor can shred all kinds of vegetables.这架食品加工机可将各种蔬菜切丝切条。

8 applied   

adj.应用的；v.应用，适用

参考例句：

• She plans to take a course in applied linguistics.她打算学习应用语言学课程。
• This cream is best applied to the face at night.这种乳霜最好晚上擦脸用。