VOA慢速英语2013 Science in the News – Aspirin

 

Science in the News – Aspirin¹

From VOA Learning English, this is Science in the News.  I'm Mario Ritter.

And I'm Avi Arditti.  Today, we tell the story of aspirin.

People have known since ancient times that aspirin helps to reduce pain and high body temperature. But that is not all aspirin can do. It has gained important new uses in recent years. Small amounts of the drug may help prevent a heart attack or stroke.

One study showed that some people who took two aspirin pills a day had lower rates of colorectal cancer. And researchers say aspirin may help patients with colon² cancer live longer. But others say the acid in aspirin can cause bleeding in the stomach and intestines⁴. And studies showed that aspirin or other pain medicines may lead to loss of eyesight and hearing.

So, how did aspirin become so important? The story begins with a willow⁵ tree. Two thousand years ago, the Greek doctor Hippocrates advised his patients to chew on the bark and leaves of the willow. The tree contains the chemical salicin. In the 1800s, researchers discovered how to make salicylic acid from salicin. In 1897, a chemist named Felix Hoffmann at Friedrich Bayer and Company in Germany created acetyl salicylic acid. Later, it became the active substance in a medicine that Bayer called aspirin.

In 1982, a British scientist shared the Nobel Prize in Medicine in part for discovering how aspirin works. Sir John Vane found that aspirin blocks the body from making natural substances called prostaglandins. Prostaglandins have several effects on the body. Some cause pain and the expansion, or swelling⁷, of damaged tissue. Others protect the lining⁸ of the stomach and small intestine³. Prostaglandins make the heart, kidneys and blood vessels¹⁰ work well.

But there is a problem. Aspirin works against all prostaglandins, good and bad. Scientists have also learned how aspirin interferes¹² with an enzyme¹³. One form of this enzyme makes the prostaglandin that causes pain and swelling. Another form creates a protective effect. So aspirin can reduce pain and swelling in damaged tissues. But it can also harm the inside of the stomach and small intestine. And sometimes it can cause bleeding.

Many people take aspirin to reduce the risk of a heart attack or stroke from blood clots¹⁴. Clots can block the flow of blood to the heart or brain and cause a heart attack or stroke. Scientists say aspirin prevents blood cells called platelets from sticking together to form clots.

A California doctor named Lawrence Craven first reported this effect in the 1950s. He observed unusual bleeding in children who chewed on an aspirin product to ease the pain after a common operation. Doctor Craven believed the bleeding took place because aspirin prevented blood from thickening. He thought this effect might help prevent heart attacks caused by blood clots. He examined the medical records of 8,000 aspirin users and found no heart attacks in this group. He invited other scientists to test his ideas. But it was years before large studies took place.

Charles Hennekens of Harvard Medical School led one of the studies. In 1983, he began to study more than 22,000 healthy male doctors over 40 years of age. Half took an aspirin every other day. The others took what they thought was aspirin. But it was only a placebo¹⁵, an inactive substance. Five years later, Dr. Hennekens reported that people who took aspirin reduced their risk of a heart attack. But they had a higher risk of bleeding in the brain than the other doctors.

A few years ago, a group of experts examined studies of aspirin at the request of federal health officials in the United States. The experts said people with an increased risk of a heart attack should take a low-strength aspirin every day. Aspirin may help someone who is having a heart attack caused by a blockage¹⁶ in a blood vessel⁹. Aspirin thins the blood, so the blood may be able to flow past the blockage. But experts say people should seek emergency help immediately. And they say an aspirin is no substitute for treatment, only a temporary help. 

But what about reducing pain? Aspirin competes with other medicines for reducing pain and high body temperature. The competition includes acetaminophen, the active substance in products like Tylenol. It also includes ibuprofen, the active substance in products such as Advil. Like ibuprofen, aspirin is an NSAID -- a non-steroidal anti-inflammatory drug.

Several studies have found that men who take aspirin or other NSAIDS have a decreased risk of prostate cancer. The prostate is a gland⁶ and part of the male reproductive system. Researchers at the Mayo Clinic in Minnesota wanted to see how NSAIDs might affect prostates that are enlarged, but not cancerous.  They followed the health of 2,500 men for 12 years. The researchers said these drugs may delay or stop development of an enlarged prostate. They said the risk of an enlarged prostate was 50 percent lower in the NSAID users than the other men. The risk of bladder problems was 35 percent lower. 

Other studies have suggested that aspirin can help with cancer prevention and survival.   They showed that aspirin may help prevent cancers of the stomach, intestines and colon. In 2008, European researchers reported that aspirin may have what they called a “long-term protective effect against colorectal cancer.”   Peter Rothwell of the University of Oxford¹⁷ led the researchers. They found that people who took one aspirin a day for about six years reduced their risk of colon cancer by 24 percent. And, deaths from the disease dropped by 35 percent.

In 2010, the Lancet published the combined results of a larger observational study, also led by Professor Rothwell. This time, he and other researchers found that taking a small aspirin once a day reduced death rates from a number of common cancers.

Aspirin does not help everything, however. It can cause problems, like an increased danger of stomach bleeding and ulcers¹⁸. And it can interfere¹¹ with other medicines. Also, some people should not take aspirin. These include people who take other blood thinners or have bleeding disorders¹⁹. Pregnant women are usually also told to avoid aspirin.

Research has shown a link between aspirin use and a condition called Reye's syndrome²⁰. Children’s doctors say patients up to age 19 should not take anything containing salicylatic products when sick with high temperatures. Recently, American researchers reported finding a small link between aspirin use and one kind of blindness. Age-related macular degeneration, or AMD, affects older adults. It limits their ability to see objects directly in front of them.

Barbara Klein of the University of Wisconsin led the study. She and her team found that people who regularly took aspirin for 10 years or more had a small increase in the risk of advanced or “late” AMD. "Regularly" meant at least twice a week for more than three months. In a separate study, Australian researchers found that people who take aspirin regularly for many years are more likely to develop neovascular AMD.

This study involved nearly 2,400 adults. Almost 11 percent of them identified themselves as regular aspirin users. Eye tests were performed after five, 10 and 15 years.  The researchers found that aspirin takers had twice the risk of neovascular, or “wet,” AMD in comparison to non-regular aspirin users. The findings were reported in December 2012 in the Journal of the American Medical Association.

American researchers found a link between hearing loss in women and their use of ibuprofen or acetaminophen. The researchers studied information about more than 62,000 women between 31 and 48 years of age. The researchers examined how often the women reported using aspirin, ibuprofen or acetaminophen. The information covered the period from 1995 to 2009. Just over 10,000 women reported some hearing loss.

The study was the work of researchers at Brigham and Women’s Hospital in Massachusetts. Lead researcher Sharon Curhan noted²¹ that NSAIDS may reduce blood flow to the cochlea, the hearing organ, and affect its ability. She noted that while such medicines can be purchased without a doctor’s order, they still carry possible side effects.

Experts say most people should not take aspirin for disease prevention without first talking to a doctor because there are risks. Some researchers have even said that some people get little or no protection from aspirin. So research continues on one of the oldest and most widely used drugs in the world.

This Science in the News was written by George Grow.  Our producer was June Simms.  I'm Mario Ritter.

And I'm Avi Arditti. Join us again next week for more news about science on the Voice of America.

1 aspirin   

n.阿司匹林

参考例句：

• The aspirin seems to quiet the headache.阿司匹林似乎使头痛减轻了。
• She went into a chemist's and bought some aspirin.她进了一家药店，买了些阿司匹林。

2 colon   

n.冒号，结肠，直肠

参考例句：

• Here,too,the colon must be followed by a dash.这里也是一样，应当在冒号后加破折号。
• The colon is the locus of a large concentration of bacteria.结肠是大浓度的细菌所在地。

3 intestine   

adj.内部的；国内的；n.肠

参考例句：

• This vitamin is absorbed through the walls of the small intestine.这种维生素通过小肠壁被吸收。
• The service productivity is the function,including external efficiency,intestine efficiency and capacity efficiency.服务业的生产率是一个包含有外部效率、内部效率和能力效率的函数。

4 intestines   

n.肠( intestine的名词复数 )

参考例句：

• Perhaps the most serious problems occur in the stomach and intestines. 最严重的问题或许出现在胃和肠里。 来自辞典例句
• The traps of carnivorous plants function a little like the stomachs and small intestines of animals. 食肉植物的捕蝇器起着动物的胃和小肠的作用。 来自辞典例句

5 willow   

n.柳树

参考例句：

• The river was sparsely lined with willow trees.河边疏疏落落有几棵柳树。
• The willow's shadow falls on the lake.垂柳的影子倒映在湖面上。

6 gland   

n.腺体，(机)密封压盖，填料盖

参考例句：

• This is a snake's poison gland.这就是蛇的毒腺。
• Her mother has an underactive adrenal gland.她的母亲肾上腺机能不全。

7 swelling   

n.肿胀

参考例句：

• Use ice to reduce the swelling. 用冰敷消肿。
• There is a marked swelling of the lymph nodes. 淋巴结处有明显的肿块。

8 lining   

n.衬里，衬料

参考例句：

• The lining of my coat is torn.我的外套衬里破了。
• Moss makes an attractive lining to wire baskets.用苔藓垫在铁丝篮里很漂亮。

9 vessel   

n.船舶；容器，器皿；管，导管，血管

参考例句：

• The vessel is fully loaded with cargo for Shanghai.这艘船满载货物驶往上海。
• You should put the water into a vessel.你应该把水装入容器中。

10 vessels   

n.血管( vessel的名词复数 )；船；容器；（具有特殊品质或接受特殊品质的）人

参考例句：

• The river is navigable by vessels of up to 90 tons. 90 吨以下的船只可以从这条河通过。 来自《简明英汉词典》
• All modern vessels of any size are fitted with radar installations. 所有现代化船只都有雷达装置。 来自《现代汉英综合大词典》

11 interfere   

v.(in)干涉，干预；(with)妨碍，打扰

参考例句：

• If we interfere, it may do more harm than good.如果我们干预的话，可能弊多利少。
• When others interfere in the affair,it always makes troubles. 别人一卷入这一事件，棘手的事情就来了。

12 interferes   

vi. 妨碍，冲突，干涉

参考例句：

• The noise interferes with my work. 这噪音妨碍我的工作。
• That interferes with my plan. 那干扰了我的计划。

13 enzyme   

n.酵素，酶

参考例句：

• Above a certain temperature,the enzyme molecule will become unfolded.超过一定温度，酶分子将会展开。
• An enzyme that dissolves the fibrin of blood clots.能溶解血凝块中的纤维的酶。

14 clots   

n.凝块( clot的名词复数 )；血块；蠢人；傻瓜v.凝固( clot的第三人称单数 )

参考例句：

• When you cut yourself, blood clots and forms a scab. 你割破了，血会凝固、结痂。 来自《简明英汉词典》
• Milk clots when it turns sour. 奶变酸就凝块。 来自《现代英汉综合大词典》

15 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。

16 blockage   

n.障碍物；封锁

参考例句：

• The logical treatment is to remove this blockage.合理的治疗方法就是清除堵塞物。
• If the blockage worked,they could retreat with dignity.如果封锁发生作用，他们可以体面地撤退。

17 Oxford   

n.牛津（英国城市）

参考例句：

• At present he has become a Professor of Chemistry at Oxford.他现在已是牛津大学的化学教授了。
• This is where the road to Oxford joins the road to London.这是去牛津的路与去伦敦的路的汇合处。

18 ulcers   

n.溃疡( ulcer的名词复数 )；腐烂物；道德败坏；腐败

参考例句：

• Detachment of the dead cells produces erosions and ulcers. 死亡细胞的脱落，产生糜烂和溃疡。 来自辞典例句
• 75% of postbulbar ulcers occur proximal to the duodenal papilla. 75％的球后溃疡发生在十二指肠乳头近侧。 来自辞典例句

19 disorders   

n.混乱( disorder的名词复数 )；凌乱；骚乱；（身心、机能）失调

参考例句：

• Reports of anorexia and other eating disorders are on the increase. 据报告，厌食症和其他饮食方面的功能紊乱发生率正在不断增长。 来自《简明英汉词典》
• The announcement led to violent civil disorders. 这项宣布引起剧烈的骚乱。 来自《简明英汉词典》

20 syndrome   

n.综合病症；并存特性

参考例句：

• The Institute says that an unidentified virus is to blame for the syndrome. 该研究所表示,引起这种综合症的是一种尚未确认的病毒。
• Results indicated that 11 fetuses had Down syndrome. 结果表明有11个胎儿患有唐氏综合征。

21 noted   

adj.著名的，知名的

参考例句：

• The local hotel is noted for its good table.当地的那家酒店以餐食精美而著称。
• Jim is noted for arriving late for work.吉姆上班迟到出了名。