VOA慢速英语2012 SCIENCE IN THE NEWS - Cancer Drug Finds HIV Hidden in the Body

 

SCIENCE IN THE NEWS - Cancer Drug Finds HIV Hidden in the Body

SHIRLEY GRIFFITH: This is SCIENCE IN THE NEWS, in VOA Special English. I’m Shirley Griffith.

CHRISTOPHER CRUISE: And I’m Christopher Cruise. Today, we tell about an anti-cancer drug recently shown to fight HIV, the virus that causes the disease AIDS. We tell about another drug that may help reduce the number of HIV infections. And we have a report on how researchers are turning to the high seas for new medicines.

(MUSIC)

SHIRLEY GRIFFITH: People infected with the human immunodeficiency virus must take anti-retroviral drugs for the rest of their lives to keep HIV under control. If they fail to do so, HIV-infected cells hidden within the body can become active. When that happens, the infection can return and attack the body, causing AIDS.

Recently, researchers discovered that a drug used to treat cancer can find and attack HIV-infected cells. Researchers say the discovery is an important step in the effort to find a way to cure those infected.

HIV has found a way to survive inside the human body by making itself part of the genetic¹ structure of T-cells. These white blood cells are part of the body’s natural defenses for fighting disease. They also are targets of the AIDS virus.

CHRISTOPHER CRUISE: Anti-retroviral drugs can suppress HIV to levels that are difficult to measure. That gives the body’s natural defense² system a chance to repair itself. Yet the virus remains³ present in extremely small amounts -- in one of every one million T-cells. But it will come back to life if the infected individual ever stops taking anti-retroviral drugs.

Now, researchers have found a way to force the virus out of its hiding place. Their weapon is a drug used for treating lymphoma -- a rare and sometimes deadly cancer.

David Margolis is a professor of microbiology and immunology at the University of North Carolina, Chapel⁴ Hill. He has been studying how HIV hides within immune-system cells. He says that in some lymphomas, the drug vorinostat makes cancer cells die. But he says that in HIV-infected cells, vorinostat causes the virus to show itself.

DAVID MARGOLIS: “Theoretically, doing this clinically would be a way to sort of unmask the hidden virus -- flush the virus out of hiding. And that might then allow us to develop ways to get rid of the leftover⁵ virus in people that are on treatment so that they could stop treatment and there would be nowhere for the virus to come back from.”

SHIRLEY GRIFFITH: Professor Margolis and his team studied eight HIV-infected patients who were taking anti-retroviral drugs. In all eight men, the spread of the virus was said to be under control. Their levels of HIV CD4 T cells -- which the virus uses to reproduce itself -- were measured both before and after the men were given vorinostat.

DAVID MARGOLIS: “What we saw in every single person was a tiny amount of the virus detectable⁶ before the dose of the drug. And the amount of virus that was detectable went up on average about five-fold, five times, after just a single exposure to the drug.”

Professor Margolis says his experiment shows that hidden HIV can be forced out of hiding with vorinostat. He says the virus can then be targeted for destruction by anti-AIDS drugs. But he says none of the infected men were cured.

The professor carried out the study with the help of four other teams of researchers. They were from the National Cancer Institute, the Harvard University School of Public Health, University of California, San Diego, and Merck and Company -- the maker⁷ of vorinostat.

(MUSIC)

CHRISTOPHER CRUISE: The United States Food and Drug Administration recently approved a drug that may help reduce the number of HIV infections. The drug, Truvada, is for healthy people to take to reduce their risk of infection. They are to swallow a single Truvada pill every day to protect themselves against HIV.

The approval came after years of research and testing. The drug is already used in many other countries to treat AIDS patients. The FDA approved Truvada in two thousand four for use with other anti-retroviral drugs to treat HIV-infected people twelve years and older. It will now also be used to protect people who are not infected, but have a high risk of getting the disease.

SHIRLEY GRIFFITH: FDA officials say the safety of Truvada was confirmed in two large studies. One study involved more than four thousand seven hundred heterosexual couples. In these relationships, one person was infected with HIV; their partner was not. Tests showed that Truvada reduced the risk of becoming infected by seventy-five percent when compared with a pill to a placebo⁸ or harmless substance. 

Kali Lindsey of the National Minority AIDS Council says the drug could have a major effect.

KALI LINDSEY: “Using Truvada -- or pre-exposure prophylaxis -- to prevent acquiring HIV for an HIV negative person is a game-changer, and it’s something that I believe is going to really take us to the next level.”

Gottfried Hirnchall is the director of the HIV/AIDS program at the World Health Organization in Switzerland. He spoke⁹ to VOA on Skype.

DR. GOTTFRIED HIRNCHALL: “We have to really see how this could best be done and which would be the populations or the individuals where this would pay off.”

Dr. Hirnchall says intervention¹⁰ with Truvada is not for everyone.

DR. GOTTFRIED HIRNCHALL: “Let’s remember, once you start on pre-exposure prophylaxis you cannot just take it some days and not on other days. So we will really have to provide the support to people to take this every single day of their life. And let us also not forget we have many other prevention methods now available that we can use.”

CHRISTOPHER CRUISE: Using Truvada can be costly¹¹. Only those who can pay for the drug for the rest of their lives can start using it. And AIDS experts say its approval does not end the need for safe sex practices, like men using condoms.

Yet not all AIDS activists¹² believe people should take Truvada. Michael Weinstein is head of the AIDS Healthcare Foundation. He says the drug can cause damage to a person’s kidneys and could cause bone loss. The FDA says serious bone or kidney problems in the Truvada studies were “uncommon.”

Michael Weinstein says people taking Truvada may stop using condoms, which he notes is a proven safe way of preventing infection. But he warns that if people do not take the drug every day, “they are going to think they are protected when they are not.” 

(MUSIC)

SHIRLEY GRIFFITH: People have turned to nature for medicines since ancient times. Modern scientists have searched the world’s rainforests for chemicals to fight disease. But now, they are turning somewhere else -- the world’s oceans.

At least twenty six drugs made from sea creatures are on the market or in development. Scientists are working to make more.

Chemist Mande Holford has an unusual partner in her search -- a marine¹³ snail¹⁴ that eats fish. She says the snails¹⁵’ tongue like proboscides is deadly. They use it to inject the target with a liquid made from poisonous amino acids called peptides.

MANDE HOLFORD: “What I’d like to say is that the snails produce sort of a cluster bomb. Inside of each venom¹⁶ you have between fifty to two hundred different peptides. And all of those peptides target something major along the nervous system. One thing that they hit is a pain signal. When they silence the pain signal, the prey¹⁷ doesn’t go into fight or flight mode.” 

The fish stays calm, even while it is being eaten. Chemists already have had one major success using the peptides – a drug called Prialt eases pain for HIV and cancer patients.

CHRISTOPHER CRUISE: David Newman directs the Natural Products Branch of America’s National Cancer Institute. After years of collecting organisms on land, his team now collects only sea life, including sponges and corals. Because these organisms cannot move, he says, they depend on chemical warfare¹⁸.

DAVID NEWMAN: “I have been known to say that weapons of mass destruction are alive and well on a coral reef, if you happen to be a fellow sponge who’s trying to encroach on someone’s territory or you’re a starfish that’s trying to eat the sponge. These are extremely toxic¹⁹ agents because of the dilution²⁰ effect of seawater.”

Such strong chemicals are inviting²¹ to any group that is looking for ways to kill cancer cells. Far below coral reefs lie what could be an even more promising²² source of new medicines: mud. Close to seventy percent of the surface of the earth is really deep, ocean mud says William Fenical. He directs the Center for Marine Biotechnology and Biomedicine at the Scripps Institute for Oceanography in California. His team looks for microorganisms living on the sea floor.

WILLIAM FENICAL: “For the last fifty years, microorganisms that occur on land have been exploited for the production of antibiotics²³, cancer drugs, and cholesterol-lowering drugs. What we believe is that the ocean is a completely new resource for such microbial product.”

His team already has two drugs in development and he sees no end to the promise of ocean-based medicines.

(MUSIC)

SHIRLEY GRIFFITH: This SCIENCE IN THE NEWS was written by Milagros Ardin and Christopher Cruise. June Simms was our producer. I’m Shirley Griffith.

CHRISTOPHER CRUISE: And I’m Christopher Cruise. You can find transcripts²⁴, MP3s and podcasts of our programs at www.voanews.cn. And you can find us on Twitter and YouTube at VOA Learning English. Join us again next week for more news about science in Special English on the Voice of America.

1 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。

2 defense   

n.防御，保卫；[pl.]防务工事；辩护，答辩

参考例句：

• The accused has the right to defense.被告人有权获得辩护。
• The war has impacted the area with military and defense workers.战争使那个地区挤满了军队和防御工程人员。

3 remains   

n.剩余物，残留物；遗体，遗迹

参考例句：

• He ate the remains of food hungrily.他狼吞虎咽地吃剩余的食物。
• The remains of the meal were fed to the dog.残羹剩饭喂狗了。

4 chapel   

n.小教堂，殡仪馆

参考例句：

• The nimble hero,skipped into a chapel that stood near.敏捷的英雄跳进近旁的一座小教堂里。
• She was on the peak that Sunday afternoon when she played in chapel.那个星期天的下午，她在小教堂的演出，可以说是登峰造极。

5 leftover   

n.剩货，残留物，剩饭；adj.残余的

参考例句：

• These narrow roads are a leftover from the days of horse-drawn carriages.这些小道是从马车时代沿用下来的。
• Wonder if that bakery lets us take leftover home.不知道那家糕饼店会不会让我们把卖剩的带回家。

6 detectable   

adj.可发觉的；可查明的

参考例句：

• The noise is barely detectable by the human ear.人的耳朵几乎是察觉不到这种噪音的。
• The inflection point at this PH is barely detectable.在此PH值下，拐点不易发现。

7 maker   

n.制造者，制造商

参考例句：

• He is a trouble maker，You must be distant with him.他是个捣蛋鬼，你不要跟他在一起。
• A cabinet maker must be a master craftsman.家具木工必须是技艺高超的手艺人。

8 placebo   

n.安慰剂；宽慰话

参考例句：

• The placebo has been found to work with a lot of different cases.人们已发现安慰剂能在很多不同的病例中发挥作用。
• The placebo effect refers to all the observable behaviors caused by placebo.安慰剂效应是指由安慰剂所引起的可观察的行为。

9 spoke   

n.（车轮的）辐条；轮辐；破坏某人的计划；阻挠某人的行动 v.讲，谈（speak的过去式）；说；演说；从某种观点来说

参考例句：

• They sourced the spoke nuts from our company.他们的轮辐螺帽是从我们公司获得的。
• The spokes of a wheel are the bars that connect the outer ring to the centre.辐条是轮子上连接外圈与中心的条棒。

10 intervention   

n.介入，干涉，干预

参考例句：

• The government's intervention in this dispute will not help.政府对这场争论的干预不会起作用。
• Many people felt he would be hostile to the idea of foreign intervention.许多人觉得他会反对外来干预。

11 costly   

adj.昂贵的，价值高的，豪华的

参考例句：

• It must be very costly to keep up a house like this.维修这么一幢房子一定很昂贵。
• This dictionary is very useful,only it is a bit costly.这本词典很有用，左不过贵了些。

12 activists   

n.（政治活动的）积极分子，活动家( activist的名词复数 )

参考例句：

• His research work was attacked by animal rights activists . 他的研究受到了动物权益维护者的抨击。
• Party activists with lower middle class pedigrees are numerous. 党的激进分子中有很多出身于中产阶级下层。 来自《简明英汉词典》

13 marine   

adj.海的；海生的；航海的；海事的；n.水兵

参考例句：

• Marine creatures are those which live in the sea. 海洋生物是生存在海里的生物。
• When the war broke out,he volunteered for the Marine Corps.战争爆发时，他自愿参加了海军陆战队。

14 snail   

n.蜗牛

参考例句：

• Snail is a small plant-eating creature with a soft body.蜗牛是一种软体草食动物。
• Time moved at a snail's pace before the holidays.放假前的时间过得很慢。

15 snails   

n.蜗牛；迟钝的人；蜗牛( snail的名词复数 )

参考例句：

• I think I'll try the snails for lunch—I'm feeling adventurous today. 我想我午餐要尝一下蜗牛——我今天很想冒险。 来自《简明英汉词典》
• Most snails have shells on their backs. 大多数蜗牛背上有壳。 来自《简明英汉词典》

16 venom   

n.毒液，恶毒，痛恨

参考例句：

• The snake injects the venom immediately after biting its prey.毒蛇咬住猎物之后马上注入毒液。
• In fact,some components of the venom may benefit human health.事实上，毒液的某些成分可能有益于人类健康。

17 prey   

n.被掠食者，牺牲者，掠食；v.捕食，掠夺，折磨

参考例句：

• Stronger animals prey on weaker ones.弱肉强食。
• The lion was hunting for its prey.狮子在寻找猎物。

18 warfare   

n.战争(状态)；斗争；冲突

参考例句：

• He addressed the audience on the subject of atomic warfare.他向听众演讲有关原子战争的问题。
• Their struggle consists mainly in peasant guerrilla warfare.他们的斗争主要是农民游击战。

19 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。

20 dilution   

n.稀释，淡化

参考例句：

• There is no hard and fast rule about dilution.至于稀释程度，没有严格的规定。
• He attributed this to a dilution effect of the herbicide.他把这归因于除草剂的稀释效应。

21 inviting   

adj.诱人的，引人注目的

参考例句：

• An inviting smell of coffee wafted into the room.一股诱人的咖啡香味飘进了房间。
• The kitchen smelled warm and inviting and blessedly familiar.这间厨房的味道温暖诱人，使人感到亲切温馨。

22 promising   

adj.有希望的，有前途的

参考例句：

• The results of the experiments are very promising.实验的结果充满了希望。
• We're trying to bring along one or two promising young swimmers.我们正设法培养出一两名有前途的年轻游泳选手。

23 antibiotics   

n.（用作复数）抗生素；（用作单数）抗生物质的研究；抗生素，抗菌素( antibiotic的名词复数 )

参考例句：

• the discovery of antibiotics in the 20th century 20世纪抗生素的发现
• The doctor gave me a prescription for antibiotics. 医生给我开了抗生素。

24 transcripts   

n.抄本（ transcript的名词复数 ）；转写本；文字本；副本

参考例句：

• Like mRNA, both tRNA and rRNA are transcripts of chromosomal DNA. tRNA及rRNA同mRNA一样，都是染色体DNA的转录产物。 来自辞典例句
• You can't take the transfer students'exam without your transcripts. 没有成绩证明书，你就不能参加转学考试。 来自辞典例句