VOA标准英语2011--Cheaper, Safer Pill Targets Tropical Parasite

Cheaper, Safer Pill Targets Tropical Parasite¹

 

Scientists have developed a new version of a drug used to treat leishmaniasis. The new formulation may help better battle this tropical parasitic² disease.

Leishmaniasis is transmitted by the bite of certain sand flies.

The World Health Organization says as many as 12 million people are infected with the leishmaniasis parasite.

Cutaneous leishmaniasis, which affects the skin and mucus membranes³, is the most common form.

But the more serious form, called visceral leishmaniasis, attacks the immune system. Without proper treatment, it's often fatal. One of the drugs used against leishmaniasisis is amphotericin B.

Amphotericin is effective, but it has from numerous drawbacks. It's expensive, it has to be given as an injection, it's highly toxic⁴ to the kidneys, and it loses effectiveness if exposed to high temperatures.

University of British Columbia researcher Kishor Wasan has been testing an improved version he developed.

Ansar Deldar, 4, shows signs of leishmaniasis, a common disease among children in Afghanistan.

He says his new formulation addresses all these shortcomings: it's much cheaper, for one, and it can be taken by mouth.

"It's tropically stable," Wasan says. "We've been able to develop a formulation that does not need refrigeration, and that's a huge factor in the developing world. And finally, we're looking at a formulation that is very effective, but does not have that kidney toxicity⁵."

To test the effectiveness of his new version of amphotericin B, Wasan sent samples to a laboratory at another university, where it was used to treat mice infected with visceral leishmaniasis.

"And the results were just remarkable," he says. "We found greater than 99 percent reduction in the parasitic load in less than five days, and remarkably⁶, in 60 percent of the animals, we completely eradicated⁷ the infection."

After the positive animal-test results, Wasan is now seeking funding to begin human trials.

The new formulation for amphotericin B may be useful against other conditions, too. The drug is also used to treat fungal infections in people with compromised immune systems, such as HIV patients and organ transplant recipients⁸.

"The impetus⁹ originally to do the work was actually in the fungal infections," Wasan says. "Physicians wanted a cheaper, more accessible form of amphotericin B than the injectable. So the oral formulation was going to help in those situations as well. So, yeah, there actually are multiple uses for this formulation."

1 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。

2 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。

3 membranes   

n.（动物或植物体内的）薄膜( membrane的名词复数 )；隔膜；（可起防水、防风等作用的）膜状物

参考例句：

• The waste material is placed in cells with permeable membranes. 废液置于有渗透膜的槽中。 来自辞典例句
• The sarcoplasmic reticulum is a system of intracellular membranes. 肌浆网属于细胞内膜系统。 来自辞典例句

4 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。

5 toxicity   

n.毒性，毒力

参考例句：

• The hoarse grunt or squeal is characteristic of toxicity.嘶哑的哼声和叫声是中毒的特征。
• Dieldrin is related to aldrin,and its toxicity to earthworms is similar.狄氏剂与艾氏剂有关，对蚯蚓的毒性是相似的。

6 remarkably   

ad.不同寻常地，相当地

参考例句：

• I thought she was remarkably restrained in the circumstances. 我认为她在那种情况下非常克制。
• He made a remarkably swift recovery. 他康复得相当快。

7 eradicated   

画着根的

参考例句：

• Polio has been virtually eradicated in Brazil. 在巴西脊髓灰质炎实际上已经根除。
• The disease has been eradicated from the world. 这种疾病已在全世界得到根除。

8 recipients   

adj.接受的；受领的；容纳的；愿意接受的n.收件人；接受者；受领者；接受器

参考例句：

• The recipients of the prizes had their names printed in the paper. 获奖者的姓名登在报上。 来自《简明英汉词典》
• The recipients of prizes had their names printed in the paper. 获奖者名单登在报上。 来自《现代英汉综合大词典》

9 impetus   

n.推动，促进，刺激；推动力

参考例句：

• This is the primary impetus behind the economic recovery.这是促使经济复苏的主要动力。
• Her speech gave an impetus to my ideas.她的讲话激发了我的思绪。