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On October 1, 1957, a new over-the-counter drug was introduced in West Germany
1957年10月1日，一种新的不需处方便可以出售的药被引入西德
that was supposed to basically cure morning sickness during pregnancy.
该药本应该治疗孕妇孕期的晨吐现象。
It was called thalidomide.
它被称为萨力多胺。
Thousands of women purchased the drug and were relieved when their morning sickness disappeared.
数千万女性购买了这种药，孕期晨吐得到治愈使她们如释重负。
And everything seemed great until later the next year,
一切看起来都那么好，直到来年，
when thousands of infants were born with severe birth defects, like brain damage and deformed limbs.
数千名新生儿出生便患有严重的先天性缺陷，比如脑损伤以及肢体发育畸形。
Doctors noticed the surge, but at first they couldn't figure out what was causing it.
医生们也注意到了这一情况，却没有找到此中诱因。
Then, two doctors, Widukind Lenz from Germany and William McBride from Australia,
之后，两名医生——来自德国的Widukind Lenz以及来自澳洲的William McBride，
both noticed that the mothers of these babies had all taken that amazing new morning sickness drug.
共同注意到这些婴儿的母亲都服用过那个神奇的孕期晨吐药。
By 1961, Lenz had proven the link between thalidomide and the birth defects, and it was pulled from the shelves.
到1961年，Lenz证明了萨力多胺与先天性缺陷之间的联系，该药下架。
But by then, thousands of infants had been born with those birth defects, and nearly 40% of them had passed away.
但那时，已有数千名新生儿有先天性缺陷，且近40%的新生儿夭折。
Rules for drug testing weren't as strict back then, and in this case, that cost thousands of lives.
那时的药品测试准则还没有如今这么严格，导致了数千条生命的逝去。
Even though they were now aware that thalidomide was a problem, scientists still didn't know why.
即使他们已经意识到了是萨力多胺的问题，但那时的科学家仍然不清楚其中原因。
Turns out the answer lies in its chemistry — or more specifically, its geometry.
事实证明，问题出现在它的化学过程中——或更具体的说，是它的几何结构上。
What researchers didn't know at the time was that there were actually two versions of the thalidomide molecule.
那时的研究员们不知道萨力多胺分子其实有两个变体。
Thalidomide, which is made up of three connected rings of carbon and nitrogen atoms,
萨力多胺，由三个碳原子和氮原子的连接环
plus some oxygen and hydrogen, is what's known as a chiral molecule.
以及一些氧和氢组成，也被称为手性分子。
Chiral comes from the Greek for hand or claw, and chemists often think of chiral molecules as being right-handed or left-handed.
手性一次来源于希腊指手或爪，化学家们通常将手性分子当成是右撇子或左撇子。
And that's because the different versions of chiral molecules — called enantiomers — are made up of all the same parts,
这是因为手性分子的不同变体——即对映体——是由所有相同部分组成，
but arranged differently. Just like your hands.
但是却以不同形式排列。就像你的双手一样。
If you try overlaying your right hand on your left,
如果你将自己的右手覆盖到左手上，
you'll see that no matter which way you turn your hands, you can't make them match up.
你会发现不论怎么弄，你的双手都无法完全重合匹配。
Even if you make your thumbs line up, one hand is palm up and the other is palm down.
即使你将自己的拇指对齐，一只手掌心朝上，另一只掌心朝下。
In other words, both hands have the same five fingers, but they're not identical.
换句话说，双手都有五根手指，但它们并非完全相同。
And molecules like thalidomide are the same way.
像萨力多胺这样的分子也是如此。
A chiral molecule has an atom — typically carbon — with four different groups attached to it.
手性分子有一个原子——典型的碳原子——有四个不同的组吸附原子上。
That's called the chiral center.
这被称为手性中心。
A group can be anything from a single atom, to a long chain, to rings.
一组可以是一个单原子、长链或结构环。
In some cases, two groups can even be connected.
在一些情况中，两组甚至可以相连。
These groups are kind of like your fingers:
这些组有点像你的手指：
in each enantiomer, the groups are attached to the chiral center in the opposite order, so they're mirror images of each other.
在每个对映体中，这些组都逆序吸附在手性中心，因此它们变成了各自的镜像
In thalidomide, for example, the chiral center is a carbon atom attached to one of the rings.
例如在萨力多胺中，手性中心是一个吸附在一个结构环上的碳原子。
It's bonded to two other carbons, a nitrogen, and a hydrogen.
它连着连个两个另外的碳原子、一个氮原子以及一个氢原子。
If you position the version of the molecule that's considered "right-handed", called the R enantiomer,
如果你找到了认为是“右撇子”的分子变体，即R对映体，
so the closest oxygen atom to the chiral center is below it,
那么离手性中心最近的氧原子就在它的下方，
the hydrogen atom attached to the center will be facing away from you.
附在中心的氢原子将背朝你。
But if you position the "left-handed", or S enantiomer, the same way, the hydrogen atom will be facing toward you.
但是如果你找到的是“左撇子”或是S对映体，那么氢原子将面朝你。
In other words, the two enantiomers are mirror images of each other.
也就是说，这两种对映体都是它们自己的镜像。
And because different receptors and enzymes inside your body react with molecules in very specific ways,
因为你体内不同的受体和酶会以非常具体的方式和分子共同发生反应，
the fact that enantiomers are mirror images means that they might react to things totally differently.
事实上对映体是镜像意味着它们可能对事情的反应完全不同。
In the case of thalidomide, scientists discovered that the R enantiomer helped with morning sickness,
在萨力多胺中，科学家发现R对映体有助于缓解晨吐，
but the S enantiomer caused those severe birth defects.
但是S对映体则会引发严重的先天缺陷。
One of the most famous — or maybe infamous — examples of how two enantiomers affect the human body is methamphetamine.
关于两个对映体如何对人体产生影响，最著名——或许是最臭名昭著的例子之一就是甲基苯丙胺。
You'd probably associate that name with the street drug, but the molecule can only really break bad when it's in its R formation.
你可能会将这个名字与街头毒品相联系，但分子仅在其R形式中变成毒品。
The S enantiomer is commonly sold over the counter as a vasodilator, and you can easily find it in vapor inhalers.
S对映体通常是作为血管舒张药在柜台销售，你可以在蒸气吸入器中轻松找到它。
But the vapor inhaler you just bought at the pharmacy isn't filled with a dangerous drug.
但是你在药房中购买的蒸气吸入器并没有被填装危险药品。
Because the S version will never be psychoactive.
因为S变体不可能对神经起到特殊作用。
After researchers discovered that only the S version of thalidomide caused birth defects,
当研究员门发现萨力多胺中仅有S变体会导致先天缺陷后，
they thought about isolating the R enantiomer so they could continue to use it to treat morning sickness.
他们考虑将R对映体隔离出来，这样他们就能够继续使用萨力多胺治疗晨吐。
But it turns out that thalidomide's R enantiomer can actually switch to the S version while inside the human body,
但事实证明，萨力多胺中的R对映体在人体内还是可以转换成S变体。
meaning that even if they'd isolated 100% pure R thalidomide, it still wouldn't be safe for pregnant women.
这意味着即使他们将R萨力多胺完全隔离出来，对孕妇而言，依旧不安全。
But in 1998, the FDA did approve thalidomide, almost forty years after rejecting it based on the birth defect problems.
但1998年，在由于先天性缺陷问题而被禁的近40年后，食品及药物管理局的确批准了萨力多胺的使用。
This time, though, it was approved for treating complications from Hansen's Disease, aka leprosy.
虽然这一次是被批准用于治疗麻疯病的并发症。
Recent research is also leading some scientists to believe that in certain cases,
近期研究也让一些科学家们相信，在某些情况中
thalidomide could help with a number of debilitating diseases, including some forms of breast cancer.
萨力多胺可以帮助一些衰竭性疾病的治疗，如乳腺癌。
They just make sure not to prescribe it to anyone who's pregnant.
只是要确保不给任何孕妇开将这种处方。
Thanks for watching this episode of SciShow, which was brought to you by our patrons on Patreon.
谢谢收看本期科学秀，本期科学秀由Patreon赞助商为您呈现。
If you want to help support this show, you can go to patreon.com/scishow.
如果你想支持科学秀，请登录patreon.com/scishow
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不要忘记登录 youtube.com/scishow进行订阅！
