Mystery Explained: How Frozen Humans Are Brought Back
By Zoё Macintosh, LiveScience Staff Writer
posted: 11 June 2010 03:49 pm ET
Yeast and worms can survive hypothermia if they are first subjected to extreme oxygen deprivation, a new study finds.
酵母和蠕蟲能夠在低溫生存，如果它們首先受到極度缺氧，一項新的研究發現。
The results could explain a long-held mystery as to how humans can be brought back to life after "freezing to death," the scientists say.
研究結果可解釋一長期擱置的奧秘，即人類如何能在“凍到死後”活回來，科學家說。
The study uncovered a previously unknown ability of organisms to survive lethal cold by temporarily slowing the biological processes that maintain life.
研究發現一種前所未知的生物能力，即在致命的寒冷中生存，以暫時減緩維持生命的生物過活。
"We have found that extension of survival limits in the cold is possible if oxygen consumption is first diminished," said researcher Mark B. Roth of Fred Hutchinson Cancer Research Center in Seattle, Wash.
“我們已發現，在寒冷中生存限制的延長是可能的，如果氧氣消耗是首先減少，”華盛頓州 西雅圖市的弗雷德哈欽森癌症研究中心的研究員馬克羅斯說。
One form of "forced hibernation," the behavior known as "suspended animation," literally involves the sudden halting of chemical reactions in the body due to the lack of oxygen. A 10-hour time lapse video of a garden worm embryo in the process of developing into a full-fledged baby worm showed a rapid process of cell division freeze to a stop upon the environment’s oxygen removal. That same cell division resumed unaffected two and a half hours after oxygen was restored.
When subjected to literally freezing temperatures, the embryos of yeast and garden worms do not live, researchers found. A full 99 percent of those in the experiment died after 24 hours of exposure to temperatures just above freezing.
But, when first deprived of oxygen in the manner described above, 66 percent of the yeast and 97 percent of the garden worms survived. Upon re-warming and reintroduction of oxygen, the "two widely divergent organisms" reanimated and showed normal life spans, said scientists in a statement.
Improved understanding of the connection between low oxygen and low temperature could lead the way to extending the shelf-life of human organs for transplantation, Roth said.
It could also explain what has been an unsolved mystery: reported instances of humans "brought back to life" after succumbing to hypothermia.
"There are many examples in the scientific literature of humans who appear frozen to death. They have no heartbeat and are clinically dead. But they can be reanimated," Roth said. "Similarly, the organisms in my lab can be put into a state of reversible suspended animation through oxygen deprivation and other means. They appear dead but are not."
Documented cases of humans successfully revived after spending hours or days without a pulse in extremely cold conditions first inspired Roth to study the relationship between human hypothermia and his own research in forced hibernation.
In the winter of 2001, the body temperature of Canadian toddler Erica Norby plunged to 61 degrees Fahrenheit (16 degrees Celsius) as she lay for hours in below-freezing weather after wandering outside wearing only a diaper. Apparently dead, she recovered completely after being re-warmed and resuscitated.
The same curious fate befell Japanese mountain climber Mitsutaka Uchikoshi in 2006, who was discovered with a core body temperature of 71 degrees F (22 degrees C) after 23 days after falling asleep on a snowy mountain.
"We wondered if what was happening with the organisms in my laboratory was also happening in people like the toddler and the Japanese mountain climber. Before they got cold did they somehow manage to decrease their oxygen consumption? Is that what protected them?" Roth said. "Our work in nematodes and yeast suggests that this may be the case, and it may bring us a step closer to understanding what happens to people who appear to freeze to death but can be reanimated."
Oxygen deprivation’s protective effect comes from the way it arrests biological processes before dangerous instabilities can develop. When reanimated, the processes continue where they left off, with no sign of disruption having occurred.
"When an organism is suspended its biological processes cannot do anything wrong," Roth said. "Under conditions of extreme cold, sometimes that is the correct thing to be doing; when you can't do it right, don't do it at all."
The ultimate goal of such research is to "buy time" for patients in physical shock, such as after heart attacks and severe blood loss, increasing their chances of survival by preserving them until they can reach medical care, researchers said in a statement. Other forms of forced hibernation include exposure to chemical agents like hydrogen sulfide.
http://www.livescience.com/health/cold-freezing-oxygen-deprivation-100611.html
冰凍的女人重得生命
Frozen woman brought back to life
NBC Newschannel
Published: January 21, 2009
Frozen Wisconsin woman revived after more than an hour with no heartbeat冷凍的威斯康星州女子復活 在超過一小時沒有心跳後
http://www2.nbc13.com/vtm/news/local/article/video_frozen_woman_brought_back_to_life/55714/
付7.8萬雪藏大腦 銀行家求永生
(明報)2010年7月3日 星期六 05:10
【明報專訊】自古以來，長生不死都是人類的夢想，35歲俄羅斯 投資銀行家奧薩奇（Innokenty Osadchy）也是一樣：「我從不想死……那不適合我。」最近他堅信找到擺脫死神的方法——他準備花一筆錢將自己大腦冷藏，等待未來科技出現，將它移植到新的身體重生。俄羅斯一間人體冷凍公司目前已替多名客人儲存了遺體和頭顱，以待未來「翻生」，儘管有專家質疑，這是騙財伎倆。
奧薩奇說：「為何我在數十年後要死掉？我從來就不想死，1年後不想，100萬年後也一樣。」他和其他俄羅斯人體冷凍公司「KrioRus」的客戶都相信，大腦的運作就像電腦硬碟機，當中的內容可以冷凍並保存到未來。
經營人體冷藏公司Krio Rus的梅德韋杰夫（Danila Medvedev）說：「我們知道人格特質是儲存於大腦中。因此當一個人的肉身老化，就再沒理由保存它……我們告訴客戶，只冷凍大腦相對較便宜安全，亦可保存得更好。」
現保存4遺體8人頭
在法國 及全球多數國家，將人體冷凍（Cryonics）都屬違法，但KrioRus現已儲存4具完整遺體與8個人頭，存放在充滿液體氮的金屬筒裏。雖有家屬將冷凍人的身體領回家保存，但絕大部分客戶的身體都由KrioRus保管在一舊貨倉內。梅德韋杰夫聲言，醫學日新月異，「一旦你能在細胞層次作納米手術……你就可以把冷凍人逐步暖化，接著他會重生」。
該公司2005年成立已來，據報已有30個客戶簽約，冷藏大腦收費1萬美元 （約7.8萬港元），冷藏全身需3萬美元（約23萬港元），所有都是預繳的。梅德韋杰夫解釋：「當你的客戶要死掉才可以使用你的服務，你當然要設立一個可以預繳的系統。」
對這些冷藏人來說，「死亡」不是他們心跳停頓。梅德韋杰夫說：「若你的腦壞掉，你就的的確確死了。」因此KrioRus公司會在他們的顧客判斷定「法定死亡」，甚或在之前盡量找方法冷藏他們腦部中的灰色物質。
專家：詐騙伎倆
但曾在前蘇聯冷凍生物科學機構工作的專家，對這項服務嗤之以鼻。專家格里申科（Valentin Grishenko）說：「他們在騙人，並拿走很多錢。這是詐騙。若你今天冷凍了一具身體——即使是活生生冷凍以及他是健康的，他在解凍後，也不能再生存。科學家至今仍不能冷凍及保存器官，只能保存細胞。」
但梅德韋杰夫否認為客戶提供不可能達成的願望。「我們不給保證，但我會說不嘗試的話會很愚蠢。」
法新社
http://hk.news.yahoo.com/article/100702/4/iyx3.html
amazing frozen frog
神奇的冰凍青蛙
西元2007年02月10日
英華裔醫生冒險將女嬰心臟停跳20分鐘實施手術
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