VOA标准英语2013--Study: Immune System Weakens in Space

 

Study: Immune System Weakens in Space

During the final flight of the US space shuttle Atlantis in the summer of 2011, one of the most important pieces of scientific cargo¹ on board was a medical experiment designed to test how the human immune system responds to stress and disease in the microgravity conditions of Earth orbit.

The experiment contained samples of living human cells housed in a sterile², temperature-controlled module³. Astronauts pushed a button to infect the cells with a common bacterial⁴ toxin⁵ that causes sepsis, a severe and potentially lethal⁶ skin infection. 

Cells in space didn't fight infection

The module spent two weeks in space and researchers at the U.S. Army Medical Command have spent the past two years analyzing⁷ the data.

They compared that data with the results of a parallel experiment conducted on Earth at the same time, under normal gravity conditions.

The same cell line was used to minimize variation between the two experiments.

“We did a micro-array analysis, where we screen 30,000 to 40,000 genes⁹ at a time,” said Rasha Hammamieh, deputy director of the Integrative Systems Biology Program at the Medical Command and lead scientist on the project, 

The cell samples that went into space showed a diminished ability to activate¹⁰ a normal immune response, according to Hammamieh. 

“This means that the cells are not able to respond to a pathogen anymore," she said. "For an astronaut, that means that it will be easier to get sick because their immune system is weakening.”

Parallels to stress in war

The cells in the space shuttle experiment were so busy dealing¹¹ with microgravity that they barely put up a fight against infections, said Marti Jett, director of the Integrative Systems Biology Program at the Medical Command.

These results were very similar to those of a study she and her colleagues conducted a couple of years ago with Army Ranger¹² trainees¹³ under battlefield conditions.

“We saw a rather similar thing there," Jett said, "that these young men were so stressed from reduced sleep, their heavy exercise, their activities, that their immune cells simply did not respond very well, when ex-vivo [outside the body] exposed the cells to a variety of pathogens.” 

This weakened immune response echoed the results with the space shuttle samples. But the Atlantis experiment revealed other effects.

Researchers found the reduced gravity also activated¹⁴ certain genes in the human tissue involved with rheumatoid arthritis¹⁵ and tumor¹⁶ growth, raising additional health concerns for human space flight.

Could lead to new therapies

Identifying which gene⁸ molecules¹⁸ were responsible for the weakened immune response offers hope for therapeutic¹⁹ strategies, both in space and on Earth. 

“If one molecule¹⁷ is not as active as it should be in space, how can we make this molecule more active?" Hammamieh said. "This way we can induce the immune system of astronauts or humans in space.”

She hopes to follow up with a study that will send mice with induced wounds up to the International Space Station to explore how microgravity affects healing. The results could be especially important for astronauts heading into space on longer missions, like those planned to an asteroid²⁰ and Mars.

1 cargo   

n.(一只船或一架飞机运载的)货物

参考例句：

• The ship has a cargo of about 200 ton.这条船大约有200吨的货物。
• A lot of people discharged the cargo from a ship.许多人从船上卸下货物。

2 sterile   

adj.不毛的，不孕的，无菌的，枯燥的，贫瘠的

参考例句：

• This top fits over the bottle and keeps the teat sterile.这个盖子严实地盖在奶瓶上，保持奶嘴无菌。
• The farmers turned the sterile land into high fields.农民们把不毛之地变成了高产田。

3 module   

n.组件，模块，模件；(航天器的)舱

参考例句：

• The centre module displays traffic guidance information.中央模块显示交通引导信息。
• Two large tanks in the service module held liquid oxygen.服务舱的两个大气瓶中装有液态氧。

4 bacterial   

a.细菌的

参考例句：

• Bacterial reproduction is accelerated in weightless space. 在失重的空间，细菌繁殖加快了。
• Brain lesions can be caused by bacterial infections. 大脑损伤可能由细菌感染引起。

5 toxin   

n.毒素，毒质

参考例句：

• Experts have linked this condition to a build-up of toxins in the body.专家已把这一病症与体内毒素的积累联系起来。
• Tests showed increased levels of toxin in shellfish.检验表明水生有壳动物的毒素水平提高了。

6 lethal   

adj.致死的；毁灭性的

参考例句：

• A hammer can be a lethal weapon.铁锤可以是致命的武器。
• She took a lethal amount of poison and died.她服了致命剂量的毒药死了。

7 analyzing   

v.分析；分析( analyze的现在分词 )；分解；解释；对…进行心理分析n.分析

参考例句：

• Analyzing the date of some socialist countries presents even greater problem s. 分析某些社会主义国家的统计数据，暴露出的问题甚至更大。 来自辞典例句
• He undoubtedly was not far off the mark in analyzing its predictions. 当然，他对其预测所作的分析倒也八九不离十。 来自辞典例句

8 gene   

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。

9 genes   

n.基因( gene的名词复数 )

参考例句：

• You have good genes from your parents, so you should live a long time. 你从父母那儿获得优良的基因，所以能够活得很长。 来自《简明英汉词典》
• Differences will help to reveal the functions of the genes. 它们间的差异将会帮助我们揭开基因多种功能。 来自英汉非文学 - 生命科学 - 生物技术的世纪

10 activate   

vt.使活动起来，使开始起作用

参考例句：

• We must activate the youth to study.我们要激励青年去学习。
• These push buttons can activate the elevator.这些按钮能启动电梯。

11 dealing   

n.经商方法，待人态度

参考例句：

• This store has an excellent reputation for fair dealing.该商店因买卖公道而享有极高的声誉。
• His fair dealing earned our confidence.他的诚实的行为获得我们的信任。

12 ranger   

n.国家公园管理员，护林员；骑兵巡逻队员

参考例句：

• He was the head ranger of the national park.他曾是国家公园的首席看守员。
• He loved working as a ranger.他喜欢做护林人。

13 trainees   

新兵( trainee的名词复数 )； 练习生； 接受训练的人； 训练中的动物

参考例句：

• We've taken on our full complement of new trainees. 我们招收的新学员已经满额了。
• The trainees were put through an assault course. 受训人员接受了突击训练课程。

14 activated   

adj. 激活的 动词activate的过去式和过去分词

参考例句：

• The canister is filled with activated charcoal.蒸气回收罐中充满了活性炭。

15 arthritis   

n.关节炎

参考例句：

• Rheumatoid arthritis has also been linked with the virus.风湿性关节炎也与这种病毒有关。
• He spent three months in the hospital with acute rheumatic arthritis.他患急性风湿性关节炎，在医院住了三个月。

16 tumor   

n.（肿）瘤，肿块(英)tumour

参考例句：

• He was died of a malignant tumor.他死于恶性肿瘤。
• The surgeons irradiated the tumor.外科医生用X射线照射那个肿瘤。

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 therapeutic   

adj.治疗的，起治疗作用的；对身心健康有益的

参考例句：

• Therapeutic measures were selected to fit the patient.选择治疗措施以适应病人的需要。
• When I was sad,music had a therapeutic effect.我悲伤的时候，音乐有治疗效力。

20 asteroid   

n.小行星；海盘车(动物)

参考例句：

• Astronomers have yet to witness an asteroid impact with another planet.天文学家还没有目击过小行星撞击其它行星。
• It's very unlikely that an asteroid will crash into Earth but the danger exists.小行星撞地球的可能性很小，但这样的危险还是存在的。