Now, usually when I mention suspended animation,

今日は仮死状態の研究について話します

people will flash me the Vulcan sign and laugh.

仮死状態の話を持ち出すと大抵の人は

But now, I'm not talking about gorking people out

バルカン式挨拶をして笑いますが

to fly to Mars or even Pandora,

今日話すのは 人に大量の鎮静剤を投与して

as much fun as that may be.

火星やパンドラに飛ばすことではありません

I'm talking about

それも面白いかもしれませんが

the concept of using suspended animation

私が話すのは

to help people out in trauma.

仮死状態を利用して外傷を負った人々を

So what do I mean

救うというアイデアです

when I say "suspended animation"?

では「仮死状態」と言うとき

It is the process by which

どういう意味で言っているのか？

animals de-animate,

これは動物が生気をなくし

appear dead

死んだかのように見えるのに

and then can wake up again without being harmed.

何の支障もなく

OK, so here is the sort of big idea:

再び意識を戻せるプロセスです

If you look out at nature,

さてここでちょっと驚く見解があります

you find that

自然を見渡すと

as you tend to see suspended animation,

気づきますが

you tend to see immortality.

仮死状態があるところには

And so, what I'm going to tell you about

生命の永続性が見られる傾向があるのです

is a way to tell a person who's in trauma --

ですから 私がお話しするのは

find a way to de-animate them a bit

患者を少し仮死状態に近づける方法を見つけることです

so they're a little more immortal

そうすれば

when they have that heart attack.

心臓発作の患者も

An example of an organism or two

簡単に死なせないですみます

that happens to be quite immortal

極めて永続性のある生物の例を

would be plant seeds

１つか２つ挙げると

or bacterial spores.

植物の種や

These creatures are

細菌胞子があります

some of the most immortal life forms on our planet,

これらの生物は

and they tend to spend most of their time

地球上の最も永続性のある生命体の代表で

in suspended animation.

ほとんどの時間を

Bacterial spores are thought now by scientists

仮死状態で過ごす傾向にあります

to exist as individual cells

科学者らによると 細菌胞子は

that are alive, but in suspended animation

個別の細胞として存在し

for as long as 250 million years.

仮死状態であれば

To suggest that this all, sort of, about little, tiny creatures,

2.5億年でも存在できるそうです

I want to bring it close to home.

このような微小生物のことを分かってもらうため

In the immortal germ line

身近な例を挙げます

of human beings --

人間の

that is, the eggs that sit in the ovaries --

卵巣にある

they actually sit there in a state of suspended animation

不死胚細胞の卵子です

for up to 50 years in the life of each woman.

卵子は実際に女性の一生で最高50年ほどの間

So then there's also my favorite example

仮死状態で卵巣に存在します

of suspended animation.

それから私の気に入っている

This is Sea-Monkeys.

仮死状態の例として

Those of you with children,

シーモンキーがあります

you know about them.

子供がいる人は

You go to the pet store or the toy store,

知っていると思います

and you can buy these things.

ペットショップやおもちゃ屋で

You just open the bag, and you just dump them

購入できます

into the plastic aquarium,

袋を開けて中身を

and in about a week or so, you'll have little shrimps swimming around.

プラスチックの水槽に入れると

Well, I wasn't so interested in the swimming.

１週間ほどで 小エビが泳ぎ回るのが見られます

I was interested in what was going on in the bag,

泳ぎ自体には興味はありませんでしたが

the bag on the toy store shelf

袋の中で何が起こっているかに興味を持ちました

where those shrimp sat

おもちゃ屋に並んでいる袋

in suspended animation indefinitely.

その中に仮死状態で

So these ideas of suspended animation

半永久的に眠っているエビです

are not just about cells and weird, little organisms.

さて 仮死状態は細胞や変わった小さな生物だけに

Occasionally, human beings

見られるわけではありません

are briefly de-animated,

ごく稀に 人間が少しの間

and the stories of people who are briefly de-animated

死んだようになることもあります

that interest me the most

このような人々の話で

are those having to do with the cold.

一番関心を引くのは

Ten years ago, there was a skier in Norway

低温状況に関連するものです

that was trapped in an icy waterfall,

10年前 ノルウェーで凍った滝に落ちた

and she was there for two hours before they extracted her.

スキーヤーがいました

She was extremely cold,

救助されるまで２時間水の中にいた彼女は

and she had no heartbeat --

非常に冷たくなっていて

for all intents and purposes she was dead, frozen.

脈もありませんでした

Seven hours later,

事実上凍死でした

still without a heartbeat,

７時間後も

they brought her back to life, and she went on to be

脈がないままでしたが

the head radiologist

彼女は生き返り その後

in the hospital that treated her.

彼女を救った病院の

A couple of years later --

放射線科医長になりました

so I get really excited about these things --

２～３年後―

about a couple of years later,

この手の話には興奮するんです―

there was a 13-month-old, she was from Canada.

約２～３年後

Her father had gone out in the wintertime; he was working night shift,

カナダで生後13ヶ月の赤ん坊が

and she followed him outside in nothing but a diaper.

冬に父親が夜勤で出かけたとき

And they found her hours later,

一緒におむつだけで外に出て凍死し

frozen, lifeless,

何時間もあとに

and they brought her back to life.

見つけられたことがありました

There was a 65-year-old woman

でも赤ん坊は生き返りました

in Duluth, Minnesota last year

65歳の女性が

that was found frozen and without a pulse

去年のある冬の朝

in her front yard one morning in the winter,

ミネソタ州ダルースの自宅の前庭で

and they brought her back to life.

凍死しているのが見つかったこともありました

The next day, she was doing so well, they wanted to run tests on her.

彼女も生き返り 翌日あまりに

She got cranky and just went home.

元気なので検査しようとすると

(Laughter)

不機嫌になり帰ってしまいました

So, these are miracles, right?

（笑）

These are truly miraculous things that happen.

奇跡ですよね？

Doctors have a saying

これらは本当に起こった奇跡です

that, in fact, "You're not dead until you're warm and dead."

医者がよく言う言葉

And it's true. It's true.

「温かくて死んでいるのでなければ死んでいない」は

In the New England Journal of Medicine,

本当に正しいんです

there was a study published that showed

ニューイングランド医学誌に

that with appropriate rewarming,

発表されたある研究には

people who had suffered without a heartbeat for three hours

適切な復温を行えば

could be brought back to life without any neurologic problems.

３時間心拍がなかった人でも 神経障害を起こさず

That's over 50 percent.

生き返らせることができると書かれていました

So what I was trying to do is think of a way

50％以上の確率だそうです

that we could study

ですから私が試みていたのは

suspended animation

どうにかして仮死状態を

to think about a way

研究して

to reproduce, maybe,

どのように

what happened to the skier.

スキーヤーに起こったことを

Well, I have to tell you something very odd,

再現できるか考えることでした

and that is that being exposed to low oxygen

とても奇妙なことなのですが

does not always kill.

低酸素の環境にいても

So, in this room, there's 20 percent oxygen or so,

必ず死ぬとは限りません

and if we reduce the oxygen concentration,

この会場の酸素の濃度は20％ほどです

we will all be dead.

もしこの濃度を下げたら

And, in fact, the animals we were working with in the lab --

全員死んでしまうでしょう

these little garden worms, nematodes --

実際 私たちの研究所で使用されている

they were also dead when we exposed them to low oxygen.

小さなミミズや線虫などの生物も

And here's the thing that should freak you out.

低酸素の環境下におくと死んでしまいました

And that is that, when we lower the oxygen concentration further

でも皆さんも驚くと思いますが

by 100 times, to 10 parts per million,

酸素の濃度をさらに下げ

they were not dead,

100分の１の10ppmにすると

they were in suspended animation,

ミミズや線虫は死なずに

and we could bring them back to life without any harm.

仮死状態になります

And this precise oxygen concentration,

そして何の障害もなく生き返ることができるのです

10 parts per million,

この酸素濃度―

that caused suspended animation,

仮死状態を引き起こした

is conserved.

きっかり10ppmの濃度は

We can see it in a variety of different organisms.

一定で

One of the creatures we see it in

様々な生物の間で見られます

is a fish.

そのうちの１つは

And we can turn its heartbeat on and off by going in and out

魚です

of suspended animation like you would a light switch.

電気のスイッチのように心拍をオン・オフして

So this was pretty shocking to me,

仮死状態にできます

that we could do this.

こんなことができるとは

And so I was wondering, when we were trying

私もとてもビックリしました

to reproduce the work with the skier,

ですからスキーヤーの状態を

that we noticed that, of course,

再現しようとしていたとき

she had no oxygen consumption,

彼女が酸素を消費していなかったことに

and so maybe she was in a similar state of suspended animation.

もちろん気づきました

But, of course, she was also extremely cold.

つまり仮死状態に近かったのかもしれません

So we wondered what would happen

でも冷たくなっていたことも踏まえ

if we took our suspended animals and exposed them to the cold.

ラボの仮死状態の生物を冷却したら

And so, what we found out

どうなるだろうと考えました

was that, if you take animals

その結果分かったのは

that are animated like you and I,

皆さんと私のように

and you make them cold -- that is, these were the garden worms --

生きている生物を冷却すると

now they're dead.

使ったのはミミズですが―

But if you have them in suspended animation,

死んでしまいますが

and move them into the cold, they're all alive.

仮死状態にしてから

And there's the very important thing there:

冷却すると死なないのです

If you want to survive the cold,

これは非常に重要な点です

you ought to be suspended. Right?

寒さの中を生き延びたかったら

It's a really good thing.

仮死状態になればいいんです

And so, we were thinking about that,

これはとても素晴らしい発見です

about this relationship between these things,

そこでこれらの関連性と

and thinking about whether or not that's what happened to the skier.

これが実際スキーヤーに

And so we wondered: Might there be some agent

起こったことなのかについて考えていました

that is in us, something that we make ourselves,

「極限の寒さで死んでしまうところを

that we might be able to regulate our own metabolic flexibility

生き延びるために

in such a way as to be able to survive

代謝適応性の調節を行うことが出来る

when we got extremely cold, and might otherwise pass away?

なんらかの作用因子を

I thought it might be interesting to sort of hunt for such things.

人が体内で作っていることはあり得るだろうか」

You know?

そのようなものを探してみるのも面白いかもと

I should mention briefly here

思いました

that physiology textbooks that you can read about

ここで簡単に言っておきたいのですが

will tell you that this is a kind of heretical thing to suggest.

皆さんが目にする生理学の教科書には

We have, from the time we are slapped on the butt

このようなことは異端な考えだと書いてあります

until we take our last dying breath --

第一呼吸をしたときから

that's when we're newborn to when we're dead --

息を引きとるときまで―

we cannot reduce our metabolic rate

つまり人は生まれてから死ぬまで

below what's called a standard,

自分の代謝率を

or basal metabolic rate.

いわゆる基礎代謝率以下に

But I knew that there were examples

下げることはできません

of creatures, also mammals,

でも哺乳類も含め

that do reduce their metabolic rate

自分の代謝率を下げる生物の

such as ground squirrels and bears,

事例があるのは知っていました

they reduce their metabolic rate

ジリスやクマなどは

in the wintertime when they hibernate.

冬眠するときに

So I wondered: Might we be able to find some agent or trigger

自分の代謝率を下げます

that might induce such a state in us?

そこで考えました「このような状態を誘発する

And so, we went looking for such things.

なんらかの作用因子を見つけられないか？」

And this was a period of time when we failed tremendously.

そしてそのようなものを探し始めました

Ken Robinson is here. He talked about the glories of failure.

この時期は全くうまくいかない時期でした

Well, we had a lot of them.

ケン・ロビンソンの失敗の栄誉の話じゃないですが 失敗ばかりでした

We tried many different chemicals and agents,

ケン・ロビンソンの失敗の栄誉の話じゃないですが 失敗ばかりでした

and we failed over and over again.

たくさんの化学物質や作用因子を

So, one time, I was at home

試しましたが どれもこれもダメでした

watching television on the couch

そんなある日 私は家で

while my wife was putting our child to bed,

テレビを見ていました

and I was watching a television show.

妻が子供を寝かしつけていて

It was a television show --

私はテレビを見ていました

it was a NOVA show on PBS --

PBSの教育番組NOVAが

about caves in New Mexico.

ニューメキシコの洞窟特集をしていて

And this particular cave was Lechuguilla,

たまたま

and this cave is incredibly toxic to humans.

レチュギア洞窟を見せていました

The researchers had to suit up just to enter it.

この洞窟は人間には非常に有毒で 完全装備なしでは

It's filled with this toxic gas,

研究者は入ることもできません

hydrogen sulfide.

有毒ガスである硫化水素が

Now, hydrogen sulfide is curiously present in us.

充満しているのです

We make it ourselves.

さて面白いことに この硫化水素は人間の体内にあります

The highest concentration is in our brains.

自己生成していて

Yet, it was used

最も濃度が高いのは脳内です

as a chemical warfare agent in World War I.

でも第一次世界大戦では

It's an extraordinarily toxic thing.

化学兵器として使われていました

In fact, in chemical accidents,

極めて有毒な物質です

hydrogen sulfide is known to --

実際 化学物質事故で

if you breathe too much of it, you collapse to the ground,

硫化水素を一定以上吸い込むと

you appear dead,

倒れてしまうことが知られています

but if you were brought out into room air, you can be reanimated without harm,

そして死んだかのように見えますが

if they do that quickly.

大気のあるところに素早く連れ出されれば

So, I thought, "Wow, I have to get some of this."

支障なく生き返ることができます

(Laughter)

こりゃ手に入れなくてはと思いました

Now, it's post-9/11 America,

（笑）

and when you go into the research institute,

でも9.11テロ後のアメリカです

and you say, "Hi.

研究所に行って

I'd like to buy some concentrated,

「すみません

compressed gas cylinders

致死ガスを何本か

of a lethal gas

高濃度の圧縮ガスボンベで

because I have these ideas, see,

頂けますか

about wanting to suspend people.

実は人を仮死状態にしたいと

It's really going to be OK."

思っているんですよ

So that's kind of a tough day,

全く問題ありませんから」と

but I said, "There really is

言うのは大変でした

some basis for thinking why you might want to do this."

でも試すべき根拠は

As I said, this agent is in us,

本当にあるのだと説明しました

and, in fact, here's a curious thing,

この物質は人の体内にあり

it binds to the very place inside of your cells

実際 面白いことに

where oxygen binds, and where you burn it,

細胞の中でも まさに酸素が結合し

and that you do this burning to live.

燃焼する場所に結合します

And so we thought, like in a game of musical chairs,

この燃焼は生きるために行います

might we be able to give a person

そこで椅子取りゲームのように

some hydrogen sulfide,

硫化水素を人に与え

and might it be able to occupy that place

酸素の結合する場所を

like in a game of musical chairs where oxygen might bind?

椅子取りゲームのように

And because you can't bind the oxygen,

陣取ることはできないかと考えました

maybe you wouldn't consume it,

そうすると酸素は結合できないので

and then maybe it would reduce your demand for oxygen.

消費されることもなく

I mean, who knows?

酸素の必要量が減るかもしれません

So -- (Laughter)

あり得ますよね？

So, there's the bit about the dopamine

ですから―　（笑）

and being a little bit, what do you call it, delusional,

多少ドーパミンの心配や

and you might suggest that was it.

錯覚を少し起こす心配もありますが

And so, we wanted to find out

それくらいでしょう

might we be able to use

そこで低温下で