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【编译NatureNews——2005-04-22】臭鸡蛋味让小鼠冬眠
臭鸡蛋味让小鼠冬眠
Jessica Ebert
假死技术将为外科提供便利
通过让小鼠吸入臭鸡蛋味的硫化氢能使小鼠进入冬眠样状态。
这一发现能够改善器官的贮藏或者组织移植，并能够使得如肿瘤和中风等各种疾病的治疗更加有效。
高浓度的硫化氢能够导致呼吸抑制而致死。其在动物体能够少量生成，并在调节体温和代谢中发挥重要作用。
西雅图华盛顿大学的生化学家Mark Roth和他的合作者将小鼠置于含有少量硫化氢的空气中：数分钟内小鼠便丧失意识。它们的中心温度下降到20摄氏度左右，呼吸频率从120次下降到10次以下。研究组将这一发现公布于本期Science上。
当重新吸入纯净的空气时小鼠复苏并且未表现出明显的副作用。“这提示硫化氢可能会降低代谢率，”Roth说。
氧输送
通过降低代谢，机体对于氧的需求便减少了，对人类的许多疾病而言这可能是治疗方法的一次改革，Roth说。
在诸如中风、心梗一起其他的一些创伤性疾病而言，愈合过程由于组织供氧的缺乏而受到限制。通过减少机体的总需氧量可以改善这一状况，宾夕法尼亚匹兹堡大学的外科与重症监护医学教授Samuel Tisherman说。
“在这一期间降低总需氧量受到广泛关注。”Tisherman说。通过诱导假死可以为医生们处理创伤争取到宝贵的时间。
Roth称这种气体对肿瘤的治疗同样有益。放疗只有在靶细胞供氧好的情况下才能最好的发挥作用，但是其对正常细胞有很大的损伤作用。通过诱导冬眠可以减少正常细胞的需氧量从而对其有一定的保护作用。
“为了确定如何使用这一疗法，何时使用，以及这一疗法有何好处，还需要进行深入的研究，”Tisherman说。
为了达到这一目标，Roth和他的合作者们将在大型动物上进行假死状态的诱导。
原文：
http://www.nature.com/news/2005/050418/full/050418-13.html
Published online: 21 April 2005; | doi:10.1038/news050418-13
Eggy smell sends mice into hibernation
Jessica Ebert
Suspended animation technique could prove a boon for surgery.
It seems that mice can be coaxed into a hibernation-like state by a whiff of hydrogen sulphide, the gas found in rotten eggs.
The discovery could improve the preservation of organs or tissues for transplants, and could lead to more effective treatments for illnesses as diverse as cancer and stroke.
Hydrogen sulphide can be deadly in high concentrations, causing burns and interfering with respiration. But it is also produced in small quantities by animals, in which it is thought to play a vital role in controlling body temperature and metabolism.
Mark Roth, a biochemist at the University of Washington, Seattle, and his colleagues tried exposing mice to air laced with relatively low concentrations of the gas: within minutes, the mice seemed to fall unconscious. Their core body temperature dropped by some 20ºC, and their breathing slowed from about 120 breaths a minute to fewer than 10, the team reports in Science1.
When re-exposed to clean air after six hours, the mice bounced back without any evident side-effects, says Roth. "This indicates that it's possible to decrease metabolic rate on demand," says Roth.
Oxygen delivery
By shutting down metabolism, the body's need for oxygen diminishes, which could "revolutionize treatment for a host of human ills", says Roth.
In conditions such as stroke, cardiac arrest and other traumas, healing can be limited by the amount of oxygen that can be supplied to damaged tissues. This could be helped by reducing the body's overall need for oxygen, says Samuel Tisherman, professor of surgery and critical-care medicine at the University of Pittsburgh in Pennsylvania.
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"Decreasing total oxygen demand during that period of time is of interest," Tisherman says. And inducing a state of suspended animation would buy doctors more time to address the trauma.
Roth says the gas may also help with cancer treatments. Radiotherapy works best when the target cells are well supplied with oxygen, but it can be detrimental to healthy cells. Inducing hibernation reduces oxygen demand in healthy cells and so should help to protect them.
"A lot of work needs to be done to determine how to use the treatment, when to use it, and what kind of benefits you get," cautions Tisherman.
To that end, Roth and colleagues are working to induce a state resembling suspended animation in larger animals.
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作者:admin@医学,生命科学 2011-03-09 17:11
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