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SCIENCE IN THE NEWS - Discovery That Stored Blood Loses a Life-Saving Gas Could Solve Mystery
By Lawan Davis, Soo Jee Han and Caty Weaver1 / Broadcast: Mon, 12 Nov 2007 16:00:00 UTC
VOICE ONE:

This is SCIENCE IN THE NEWS in VOA Special English. I'm Steve Ember.

VOICE TWO:

And I'm Pat Bodnar. This week, we will tell about a gas that helps to carry oxygen from the blood. We will also report on a British sleep study. And we answer a question from Canada about a genetic3 disorder4.

(MUSIC)

VOICE ONE:


Stored blood loses nitric oxide5

Scientists have discovered that stored blood loses a life-saving gas. The discovery may explain why a great number of people get sick after receiving stored blood.

In recent years, experts have wondered why patients who should survive sometimes die after receiving a blood transfusion6. The cause of death is often a heart attack or stroke.

VOICE TWO:

Jonathan Stamler is a professor of medicine at Duke University in North Carolina. He and other researchers found that stored blood has very low levels of nitric oxide. Nitric oxide is a gas found in red blood cells. The gas helps to keep blood passages open so that oxygen in the red cells can reach the heart and other organs.

Professor Stamler and his team found that nitric oxide in blood begins to break down as soon as the blood is collected. Their findings were reported in Proceedings7 of the National Academy of Science.

VOICE ONE:

Another team of Duke University scientists carried out a separate study. Professor Stamler says that study showed the breakdown8 of nitric oxide begins within hours of blood collection. He says the life-saving gas is partly lost after three hours, and about seventy percent of it is lost after just one day. As a result, he says, there is almost no time that stored blood has enough nitric oxide.

VOICE TWO:

Scientists tested their theory on dogs and found that low levels of nitric oxide reduced the flow of blood. Professor Stamler says the scientists corrected the situation by adding nitric oxide to the stored blood. He says the extra nitric oxide repaired the ability of red blood cells to expand blood passages. He says blood when injected in animals does a very fine job of improving blood flow and getting oxygen to tissues.

Professor Stamler says people who are in serious need of a blood transfusion should have one immediately. But he says more studies are needed to show who would receive the most help from stored blood.

(MUSIC)

VOICE ONE:

A British study suggests that women who fail to get enough sleep are at higher risk than men of developing high blood pressure.

Researchers at the University of Warwick Medical School led the study. Their report was published last month in Hypertension magazine.

The researchers studied health information from more than ten thousand British public employees. The information was gathered in the nineteen eighties. At the time, the employees were between thirty-five and fifty-five years of age.

The researchers also used more recent information about some of the volunteers. This information was collected in the late nineteen nineties, and again in two thousand three and two thousand four.

VOICE TWO:

Earlier studies have shown a link between lack of sleep and an increased risk of high blood pressure, or hypertension. Hypertension is known to increase the risk of heart disease.

Blood pressure readings are measured in millimeters of mercury9 and often given as two numbers. The researchers described hypertension as blood pressure higher than or equal to a reading of one hundred forty over ninety. The volunteers were identified as having hypertension if they commonly used medicine to treat high blood pressure.

VOICE ONE:

By the end of the study, twenty percent of the people had developed high blood pressure. The risk was higher among women who did not get enough sleep. The women who slept less than or equal to five hours were two times as likely as women who slept for seven hours or more. The study found no difference between men who slept less than five hours and those sleeping seven hours or more.

Francisco Cappuccio from the Warwick Medical School led the study. He says women who sleep less than five hours a night should attempt to get more rest. He also says other evidence suggests lack of sleep as possibly influencing weight gain and conditions like diabetes10.

(MUSIC)

VOICE TWO:

An American study has examined treatment of AIDS in Africa, south of the Sahara. The study involved people who have AIDS or the virus that causes the disease.

Researchers at Boston University studied reports about adults who have HIV, the human immunodeficiency virus. The patients received HIV medicines in thirteen countries in southern Africa over a seven-year period. Two years after beginning treatment, only sixty-one percent of patients on average were still taking the medicines. The Public Library of Science reported the findings.

VOICE ONE:

Christopher Gill of Boston University says the study was designed to estimate the effectiveness of HIV drug programs in the thirteen countries. Professor Gill is an expert on infectious11 diseases. He is concerned that up to one-third of the patients discontinued their treatment. He says that for whatever reason, the programs were unable to follow the patients. He says the patients may have died or stopped using the drugs.

Professor Gill says public health officials have proved that it is possible to bring HIV medicines to poor countries. He says the problem now is to find ways to make sure people who are taking the medicines continue to do so.

(MUSIC)

VOICE TWO:

Phenylketonuria is a genetic disorder. It is also called PKU. A seven-year-old listener from Canada has a friend in China with the disorder. Sarah Sun wants to know more about PKU and how to help people with it.

People with PKU are unable to break down an amino acid called phenylalanine, or Phe. The body uses this amino acid to build proteins. There is a gene2 that helps the body take in Phe. But some people are born with genetic orders that change how the gene operates. This causes Phe levels in the blood to increase.

Extremely high levels of the amino acid can cause severe damage to a baby's brain. That is why it is important to identify the disorder in newborns so a special diet can be established early in life. Many hospitals in wealthy nations require PKU tests on young babies. Early medical intervention12 provides the best results.

VOICE ONE:

Babies with PKU who eat low-protein foods can develop normally. If they remain on the diet, they may never experience any signs of the condition. But, it is tricky13 because phenylalanine is in a lot of foods. For example, all meats and milk products have high amounts. Beans and nuts are also high in Phe. And, children with PKU should not use the non-sugar sweetener aspartame. It contains a lot of Phe. Aspartame can be found in many sugar-free products like drinks.

Everyone needs some protein for health. So, many doctors advise their PKU patients to take a special phenylalanine-free formula. The formula contains protein, vitamins, minerals and extra calories, but no Phe. Several drug companies make these products.

VOICE TWO:

In the past, doctors often only suggested this diet while their patients were babies. Older children with PKU were told they could begin to eat all foods. But, studies have shown that many older PKU patients on a normal diet have problems with thinking and remembering. So, patients now are usually advised to stay on a low protein diet their whole lives.

There are emotional sides to any health problem. Children with the disorder sometimes feel cheated out of fun and tasty foods, like French fries. The Mayo Clinic in Minnesota suggests ways to help ease the situation faced by a PKU patient. Officials there say it helps to not place a lot of attention on food. Instead, invest time and energy on other things children enjoy like a sports activity or a musical skill.

VOICE ONE:

Also, the Mayo Clinic says to be sensitive around holiday celebrations. It is not unusual for holidays to include big meals. But, they do not have to. Holiday story telling or other activities could become more important.

PKU patients need monthly blood tests to check Phe levels. They also need to keep records of what they eat and how much. This way doctors can make changes to the patients' diets as needed.

(MUSIC)

VOICE TWO:

This SCIENCE IN THE NEWS was written by Lawan Davis, Soo Jee Han and Caty Weaver. Our producer was Brianna Blake. I'm Pat Bodnar.

VOICE ONE:

And I'm Steve Ember. .


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点击收听单词发音收听单词发音  

1 weaver LgWwd     
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 gene WgKxx     
n.遗传因子,基因
参考例句:
  • A single gene may have many effects.单一基因可能具有很多种效应。
  • The targeting of gene therapy has been paid close attention.其中基因治疗的靶向性是值得密切关注的问题之一。
3 genetic PgIxp     
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。
4 disorder Et1x4     
n.紊乱,混乱;骚动,骚乱;疾病,失调
参考例句:
  • When returning back,he discovered the room to be in disorder.回家后,他发现屋子里乱七八糟。
  • It contained a vast number of letters in great disorder.里面七零八落地装着许多信件。
5 oxide K4dz8     
n.氧化物
参考例句:
  • Oxide is usually seen in our daily life.在我们的日常生活中氧化物很常见。
  • How can you get rid of this oxide coating?你们该怎样除去这些氧化皮?
6 transfusion wnbwQ     
n.输血,输液
参考例句:
  • She soon came to her senses after a blood transfusion.输血后不久她就苏醒了。
  • The doctor kept him alive by a blood transfusion.医生靠输血使他仍然活着。
7 proceedings Wk2zvX     
n.进程,过程,议程;诉讼(程序);公报
参考例句:
  • He was released on bail pending committal proceedings. 他交保获释正在候审。
  • to initiate legal proceedings against sb 对某人提起诉讼
8 breakdown cS0yx     
n.垮,衰竭;损坏,故障,倒塌
参考例句:
  • She suffered a nervous breakdown.她患神经衰弱。
  • The plane had a breakdown in the air,but it was fortunately removed by the ace pilot.飞机在空中发生了故障,但幸运的是被王牌驾驶员排除了。
9 mercury NouzIB     
n.汞,水银,水银柱
参考例句:
  • The liquid we can see in thermometers is mercury.我们看到的温度计里的液体是水银。
  • Mercury has a much greater density than water.水银的密度比水大得多。
10 diabetes uPnzu     
n.糖尿病
参考例句:
  • In case of diabetes, physicians advise against the use of sugar.对于糖尿病患者,医生告诫他们不要吃糖。
  • Diabetes is caused by a fault in the insulin production of the body.糖尿病是由体內胰岛素分泌失调引起的。
11 infectious I7jx1     
adj.传染的,有传染性的,有感染力的
参考例句:
  • Influenza is an infectious disease.流感是一种传染病。
  • What an infectious laugh she has!她的笑声多么具有感染力啊!
12 intervention e5sxZ     
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。
13 tricky 9fCzyd     
adj.狡猾的,奸诈的;(工作等)棘手的,微妙的
参考例句:
  • I'm in a rather tricky position.Can you help me out?我的处境很棘手,你能帮我吗?
  • He avoided this tricky question and talked in generalities.他回避了这个非常微妙的问题,只做了个笼统的表述。

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