VOA慢速英语2013 AS IT IS 2013-05-10 Air Pollution Linked to Increased Risk of Heart Disease

 

AS IT IS 2013-05-10 Air Pollution Linked to Increased Risk of Heart Disease

From VOA Learning English, this is As It Is. 

I’m Caty Weaver¹.  Welcome back!

Cardiovascular diseases kill about 17 million people around the world every year. Heart attacks and strokes are to blame for a large share of the deaths. And, tobacco use greatly increases the risk of developing the diseases and dying from them.

Today on As It Is, we talk about cardiovascular disease: what some new studies are showing, and ways to reduce your risk.

Urban Air and Cardiovascular Disease

Have you ever had trouble breathing while outdoors in a busy city with lots of cars and busses rolling down the street? Fine particulate² air pollution might be the cause of your trouble. This is the black, dirty gas clouds you see pouring out of the back of buses or the smoke rising from factory chimneys in urban areas.

Air pollution is a big problem in cities. It can lead to cardiovascular disease and other health problems. But now scientists say air pollution and its health risks seem to be localized. They say the level of threat people face may depend on which part of the city they live in.  Katherine Cole has more.

Atherosclerosis, or hardening of the arteries³, is a leading cause of death around the world. It can block the flow of blood to the heart or brain.

American researchers examined the part that air pollution plays in the development of atherosclerosis. They followed a group of almost 5,400 adults is six major cities. None of the adults were known to have heart disease. They were part of a larger study called the Multi-Ethnic Study of Atherosclerosis and Air Pollution.

Between 2000 and 2005, the researchers performed two non-invasive ultrasound tests on every member of the group. The exams were given three years apart, and measured the thickness of carotid artery⁴ walls.

The carotid artery carries blood to the head, neck and brain. Thickening of an arterial wall can be evidence of atherosclerosis throughout the body, even in patients with no other sign of heart disease.

The researchers found a meaningful increase in the thickening among individuals who lived in the neighborhoods with higher pollution levels. The lead researcher was Sara Adar, an epidemiologist at University of Michigan. She says their work confirmed earlier studies of the same group of people.

“Based on another study that was done in the same cohort (group) of people, they found that the amount of change that we saw for living in a high-pollution neighborhood versus⁵ living in a low pollution neighborhood would correspond to about a two percent increased risk of stroke.”

Fine particulate air pollution is widely believed to cause swelling⁶ and other conditions that can add to the development of heart disease.  Sara Adar notes that medical officials urge people to stay indoors when pollution levels are especially high. But she says doctors should discuss the dangers of air pollution directly with their patients.

“So, just as they might ask somebody, ‘do you smoke?’ or think about if someone is obese⁷, how long someone has lived in a highly polluted environment might factor into a physician’s notion of whether or not somebody is at high or low risk for cardiovascular disease.”

A report about the study of air pollution and artery hardening can be found in the online journal PLoS Medicine.

I’m Katherine Cole.

Physical activity helps prevent heart disease.

Don't Smoke, Eat Right and Exercise

The World Health Organization reports that cardiovascular diseases kill more people every year than any other disease. And the number of deaths is expected to increase from 17 million to over 23 million by the year 2030.

Yet, development of cardiovascular disease is highly preventable. Behavior plays a big part. Major risk factors are tobacco use and drinking too much alcohol, unhealthy diet and physical inactivity. The WHO says these behaviors are responsible for 80 percent of cardiovascular disease cases around the world.

So, quit smoking or do not start.  Drink alcohol in moderation. Eat foods that are low in fat, sugars and salt and include fruits and vegetables in your daily diet. And, make exercise a usual activity.

But, as you try to reduce your chances for cardiovascular disease scientists continue to search for a cure. In the next story we learn how are own immune systems might provide clues to treatment.

Growing New Blood Vessels⁹

Researchers at Yale University and University College London have discovered how some heart disease patients are able to grow new blood vessels. The new vessels permit blood to flow around blockages¹⁰ in arteries and continue on its path around the body. The discovery could mean new treatments for cardiac patients in the future.

Kelly Jean Kelly has details.

It is not uncommon¹¹ for new blood vessels to grow around blocked arteries in people with heart disease. The new blood vessels keep blood flowing through the body, feeding its organs oxygen. But those emergency blood vessels do not grow in everyone who might need them.

Researchers have been working for more than ten years to find a way to force new blood vessel⁸ formation, called angiogenesis. They used human growth factors in their research. These are enzymes¹² and hormones¹³ that support cellular¹⁴ growth.

But Yale University cell biologist Michael Simons says that the scientists were not successful. He said they found that growth factors are limited in fueling new blood vessel growth.

“They do that in normal animals and normal people. But they did not work in people with advanced illnesses and we never understood why.”

Mr. Simons and his team decided¹⁵ to look at blood vessel formation at a much earlier period in life. They studied blood vessel formation in fetuses¹⁶ to see why that process does not happen in people with severe heart disease.

Mr. Simons says organs that are damaged by decreased blood flow release a repair molecule¹⁷. It is called VEGFR. Another molecule called NRP1 attaches to VEGFR and transports it and a second repair molecule to the inside of blood vessels. This process causes healing to begin.

But, in experiments with mice researchers found that repair does not happen in mice that have damaged NRP1. Mr. Simons says angiogenesis is held back because molecules¹⁸ cannot enter damaged blood vessels.

The scientist says he believes heart patients whose bodies do not repair and grow new blood vessels also have damaged NRP1.

“So now that we understand how this works, you can now begin designing therapies that will specifically stimulate¹⁹ this pathway where you need it if you want to grow arteries. On the other hand, if your goal is to inhibit²⁰ the growth of blood vessels, you could do this of course in reverse.”

Reversing blood vessel formation would block arterial blood to cancer tumors. This could destroy tumors which need to grow and spread.

Michael Simons and his co-researchers reported about blood vessel formation in the journal Developmental Cell.

I’m Kelly Jean Kelly.

And that’s As It Is for today. Thanks for tuning²¹ in.

1 weaver   

n.织布工；编织者

参考例句：

• She was a fast weaver and the cloth was very good.她织布织得很快，而且布的质量很好。
• The eager weaver did not notice my confusion.热心的纺织工人没有注意到我的狼狈相。

2 particulate   

adj.微小的；n.微粒，粒子

参考例句：

• A special group was organized to dig up the particulate of the case.成立了一个专门小组来查明该案件的各个细节。
• Lungs retain relatively insoluble particulate material.肺脏内留有不溶解的颗粒物质。

3 arteries   

n.动脉( artery的名词复数 )；干线，要道

参考例句：

• Even grafting new blood vessels in place of the diseased coronary arteries has been tried. 甚至移植新血管代替不健康的冠状动脉的方法都已经试过。 来自《简明英汉词典》
• This is the place where the three main arteries of West London traffic met. 这就是伦敦西部三条主要交通干线的交汇处。 来自《简明英汉词典》

4 artery   

n.干线，要道；动脉

参考例句：

• We couldn't feel the changes in the blood pressure within the artery.我们无法感觉到动脉血管内血压的变化。
• The aorta is the largest artery in the body.主动脉是人体中的最大动脉。

5 versus   

prep.以…为对手，对；与…相比之下

参考例句：

• The big match tonight is England versus Spain.今晚的大赛是英格兰对西班牙。
• The most exciting game was Harvard versus Yale.最富紧张刺激的球赛是哈佛队对耶鲁队。

6 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。

7 obese   

adj.过度肥胖的，肥大的

参考例句：

• The old man is really obese,it can't be healthy.那位老人确实过于肥胖了，不能算是健康。
• Being obese and lazy is dangerous to health.又胖又懒危害健康。

8 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。

9 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》

10 blockages   

n.堵塞物( blockage的名词复数 )；堵塞，阻塞

参考例句：

• The storms could increase the risks posed by river blockages. 暴风雨会增加因河道堵塞所造成的危险。 来自互联网
• An angiogram shows the location and severity of blockages in blood vessels. 冠状动脉造影能够显示血管内的阻塞位置以及阻塞的严重程度。 来自互联网

11 uncommon   

adj.罕见的，非凡的，不平常的

参考例句：

• Such attitudes were not at all uncommon thirty years ago.这些看法在30年前很常见。
• Phil has uncommon intelligence.菲尔智力超群。

12 enzymes   

n. 酶，酵素

参考例句：

• It was said that washing powders containing enzymes remove stains more efficiently. 据说加酶洗衣粉除污更有效。
• Among the enzymes which are particularly effective are pepsin, papain. 在酶当中特别有效的是胃朊酶、木瓜酶。

13 hormones   

n. 荷尔蒙，激素 名词hormone的复数形式

参考例句：

• This hormone interacts closely with other hormones in the body. 这种荷尔蒙与体內其他荷尔蒙紧密地相互作用。
• The adrenals produce a large per cent of a man's sex hormones. 肾上腺分泌人体的大部分性激素。

14 cellular   

adj.移动的；细胞的，由细胞组成的

参考例句：

• She has a cellular telephone in her car.她的汽车里有一部无线通讯电话机。
• Many people use cellular materials as sensitive elements in hygrometers.很多人用蜂窝状的材料作为测量温度的传感元件。

15 decided   

adj.决定了的，坚决的；明显的，明确的

参考例句：

• This gave them a decided advantage over their opponents.这使他们比对手具有明显的优势。
• There is a decided difference between British and Chinese way of greeting.英国人和中国人打招呼的方式有很明显的区别。

16 fetuses   

n.胎，胎儿( fetus的名词复数 )

参考例句：

• DNA was extracted from fetuses at mid-gestation, about 10 days past conception. DNA从受孕大约10天后的中期妊娠胚胎中提取。 来自互联网
• Brucellosis is a disease that causes fetuses to abort in cattle. 普鲁士菌病是一种可以导致牲畜胎儿夭折的疾病。 来自互联网

17 molecule   

n.分子，克分子

参考例句：

• A molecule of water is made up of two atoms of hygrogen and one atom of oxygen.一个水分子是由P妈̬f婘̬ 妈̬成的。
• This gives us the structural formula of the molecule.这种方式给出了分子的结构式。

18 molecules   

分子( molecule的名词复数 )

参考例句：

• The structure of molecules can be seen under an electron microscope. 分子的结构可在电子显微镜下观察到。
• Inside the reactor the large molecules are cracked into smaller molecules. 在反应堆里，大分子裂变为小分子。

19 stimulate   

vt.刺激，使兴奋；激励，使…振奋

参考例句：

• Your encouragement will stimulate me to further efforts.你的鼓励会激发我进一步努力。
• Success will stimulate the people for fresh efforts.成功能鼓舞人们去作新的努力。

20 inhibit   

vt.阻止，妨碍，抑制

参考例句：

• Don't let ego and greed inhibit clear thinking and hard work.不要让自我和贪婪妨碍清晰的思维和刻苦的工作。
• They passed a law to inhibit people from parking in the street.他们通过一项法令以阻止人们在街上停车。

21 tuning   

n.调谐，调整，调音v.调音( tune的现在分词 )；调整；（给收音机、电视等）调谐；使协调

参考例句：

• They are tuning up a plane on the flight line. 他们正在机场的飞机跑道上调试一架飞机。 来自《简明英汉词典》
• The orchestra are tuning up. 管弦乐队在定弦。 来自《现代汉英综合大词典》