VOA标准英语2011--Scientists Try to Develop Safer Sleeping

Scientists Try to Develop Safer Sleeping Sickness Cure

Researchers say they've developed a safer way to treat sleeping sickness, a parasitic¹ disease that is fatal if not treated.
Sleeping sickness, or trypanosomiasis, is a chronic² medical problem in 36 countries of sub-Saharan Africa and treatment for one variety is highly toxic³.
Sleeping sickness is caused by two related parasites⁵, producing two varieties of the disease. The form prevalent in West Africa is more common, but the East African variety is more aggressive, and the patient can die within weeks or months of infection.
The parasite⁴ first invades the blood and lymph systems, but then crosses into the nervous system, causing symptoms like confusion, behavior change, and daytime sleepiness. Brain infection leads to inflammation and death.
For patients with the East African form of the disease, researcher Peter Kennedy says the only available treatment is itself a serious health risk.
"The problem is, the drugs for the brain disease are very, very toxic," he says. "So, untreated, everyone dies. But treated with this drug, five percent of patients die. This is an appalling⁶ figure, which just has to be improved."
Kennedy, an immunologist at the University of Glasgow in Scotland, is a leading expert on sleeping sickness. He explains that the drug, called melarsoprol, has to be injected intravenously, repeatedly, and at increasing concentrations.
So Kennedy and his colleagues combined melarsoprol with another chemical, cyclodextrin. The resulting formula doesn't have to be injected.
"What we find is that it can be given orally. And because of this, it can be absorbed from the gut⁷ more slowly. And we believe - although we don't know for sure - that one of the main reasons why it's less toxic is that there isn't this sudden rush of drug into the body, and thereby⁸ producing less toxic effects."
In testing on laboratory mice, Kennedy says the combination retained the effectiveness of melarsoprol, without the frequently fatal side effects.
But will it work the same way in humans? Sometimes, new drugs work fine in animal tests, but not with people. Kennedy says, "this is different. This is already a drug that is given to humans. What we've done is we've used the mouse model to change the molecular⁹ configuration¹⁰ of the drug so the drug becomes less toxic and effective orally."
Plans are already underway to take this new combination medicine to human trials, starting as soon as the beginning of 2013. If it all works out, he says the melarsoprol-cyclodextrin combination could lower the cost of treatment by reducing hospital stays.

1 parasitic   

adj.寄生的

参考例句：

• Will global warming mean the spread of tropical parasitic diseases?全球变暖是否意味着热带寄生虫病会蔓延呢？
• By definition,this way of life is parasitic.从其含义来说，这是种寄生虫的生活方式。

2 chronic   

adj.(疾病)长期未愈的，慢性的；极坏的

参考例句：

• Famine differs from chronic malnutrition.饥荒不同于慢性营养不良。
• Chronic poisoning may lead to death from inanition.慢性中毒也可能由虚弱导致死亡。

3 toxic   

adj.有毒的，因中毒引起的

参考例句：

• The factory had accidentally released a quantity of toxic waste into the sea.这家工厂意外泄漏大量有毒废物到海中。
• There is a risk that toxic chemicals might be blasted into the atmosphere.爆炸后有毒化学物质可能会进入大气层。

4 parasite   

n.寄生虫；寄生菌；食客

参考例句：

• The lazy man was a parasite on his family.那懒汉是家里的寄生虫。
• I don't want to be a parasite.I must earn my own way in life.我不想做寄生虫，我要自己养活自己。

5 parasites   

寄生物( parasite的名词复数 )； 靠他人为生的人； 诸虫

参考例句：

• These symptoms may be referable to virus infection rather than parasites. 这些症状也许是由病毒感染引起的，而与寄生虫无关。
• Kangaroos harbor a vast range of parasites. 袋鼠身上有各种各样的寄生虫。

6 appalling   

adj.骇人听闻的，令人震惊的，可怕的

参考例句：

• The search was hampered by appalling weather conditions.恶劣的天气妨碍了搜寻工作。
• Nothing can extenuate such appalling behaviour.这种骇人听闻的行径罪无可恕。

7 gut   

n.[pl.]胆量；内脏；adj.本能的；vt.取出内脏

参考例句：

• It is not always necessary to gut the fish prior to freezing.冷冻鱼之前并不总是需要先把内脏掏空。
• My immediate gut feeling was to refuse.我本能的直接反应是拒绝。

8 thereby   

adv.因此，从而

参考例句：

• I have never been to that city,,ereby I don't know much about it.我从未去过那座城市，因此对它不怎么熟悉。
• He became a British citizen,thereby gaining the right to vote.他成了英国公民，因而得到了投票权。

9 molecular   

adj.分子的；克分子的

参考例句：

• The research will provide direct insight into molecular mechanisms.这项研究将使人能够直接地了解分子的机理。
• For the pressure to become zero, molecular bombardment must cease.当压强趋近于零时，分子的碰撞就停止了。

10 configuration   

n.结构，布局，形态，(计算机)配置

参考例句：

• Geographers study the configuration of the mountains.地理学家研究山脉的地形轮廓。
• Prices range from $119 to $199,depending on the particular configuration.价格因具体配置而异，从119美元至199美元不等。