How do blood transfusions work? - Bill Schutt

翻译人员: Yizhuo He 校对人员: Yanyan Hong

In 1881, doctor William Halsted rushed to help his sister Minnie,

在 1881年，威廉 · 哈尔斯特医生

匆匆忙忙赶去抢救

who was hemorrhaging after childbirth.

他产后大出血的妹妹敏妮。

He quickly inserted a needle into his arm,

他很快地将一根针头 插进自己的胳膊，

withdrew his own blood, and transferred it to her.

从中抽取出他自己的血， 并将其输送给他妹妹。

After a few uncertain minutes, she began to recover.

不安的几分钟过去后， 她的身体开始恢复了。

Halsted didn’t know how lucky they’d gotten.

哈尔斯特并不知道 他们当时其实很幸运。

His transfusion only worked because he and his sister

他的输血过程之所以成功， 是因为他和他妹妹

happened to have the same blood type—

恰好是同一种血型——

something that isn’t guaranteed, even among close relatives.

而实际上，即使是至亲， 都不一定能保证血型一致。

Blood types hadn’t been discovered by Halsted’s time,

在哈尔斯特所处的时代， 血型还没有被人类发现，

though people had been experimenting with transfusions for centuries—

尽管到那时为止，

人类已经试验过 几千年的输血过程了——

mostly unsuccessfully.

当然大部分情况下都失败了。

In 1667, a French physician named Jean-Baptiste Denis

在 1667 年，法国物理学家

约翰-巴布缇斯 · 丹尼斯

became the first to try the technique on a human.

是第一位尝试 在人身上进行输血的。

Denis transfused sheep’s blood into Antoine Mauroy,

丹尼斯将羊的血转移到了

安东尼 · 玛瓦的身体中，

a man likely suffering from psychosis,

一位精神病患者，

in the hopes that it would reduce his symptoms.

希望输血能改善他的症状。

Afterward, Mauroy was in good spirits.

第一次输血之后， 玛瓦变得精神抖擞。

But after a second transfusion, he developed a fever,

但在第二次输血后， 他的症状转为了发烧，

severe pain in his lower back, intense burning in his arm,

腰部感到剧痛， 胳膊有强烈的灼烧感，

and he urinated a thick, black liquid.

并且他在小便的时候 排出了一种浓黑的液体。

Though nobody knew it at the time,

尽管在当时还没人 了解那些症状，

these were the signs of a dangerous immune response unfolding inside his body.

但那些症状其实标志着 严重的免疫反应

在他的体内进行着。

This immune response starts  with the production of proteins

这种免疫反应从产生一种叫作

called antibodies,

“抗体”的蛋白质开始，

which distinguish the body’s own cells from intruders.

它能将身体内部的细胞 与入侵细胞区分开，

They do so by recognizing the foreign proteins, or antigens,

通过识别嵌于入侵细胞膜中的

embedded in an intruder’s cell membrane.

蛋白质和抗原。

Antibodies latch onto the antigens,

抗体附着于抗原上，

signaling other immune cells to attack and destroy the foreign cells.

标志着其他的免疫细胞 开始攻击并摧毁外来细胞。

The destroyed cells are flushed from the body in urine.

被摧毁的细胞 通过尿液从体内被排出。

In extreme cases, the massive break down of cells

在极端情况下， 这种大规模的细胞分解

causes clots in the bloodstream that disrupt the flow of blood to vital organs,

会堵住血管， 影响流到重要器官的血流，

overload the kidneys, and cause organ failure.

造成肾脏过载， 并最终导致器官衰竭。

Fortunately, Denis’s patient survived the transfusion.

幸运地是，丹尼斯的病人 在那次输血后活了下来

But, after other cross-species transfusions proved fatal,

但后来，跨物种输血 被发现是致命的，

the procedure was outlawed across Europe,

这种手术后来 在欧洲被法律禁止了，

falling out of favor for several centuries.

之后的几个世纪， 这种手术渐渐被大家所遗忘了。

It wasn’t until 1901 that Austrian physician Karl Landsteiner

直到 1901 年， 奥地利物理学家

卡尔 · 兰德施泰纳

discovered blood types,

发现了血型，

the crucial step in the success of human to human blood transfusions.

人与人之间 血液传输的关键步骤。

He noticed that when different types were mixed together, they formed clots.

他发现当不同血型的血 混在一起时，会形成血块。

This happens when antibodies latch on to cells with foreign antigens,

当抗体依附于带有 外来抗原的细胞上时，

causing blood cells to clump together.

就会导致血细胞聚集在一起。

But if the donor cells are the same blood type as the recipient’s cells,

但是当献血者的血型与 受血者的血型相同时，

the donor cells won’t be flagged for destruction, and won’t form clumps.

献血者的血细胞就不会被

标记为待摧毁， 也不会形成血块。

By 1907,

到了 1907 年，

doctors were mixing together small amounts of blood before transfusing it.

医生们会在输血前 先把少量的血混合在一起。

If there were no clumps, the types were a match.

如果不会形成血块， 就说明血型相符。

This enabled them to save thousands of lives,

这使得他们拯救了 成百上千的生命，

laying the foundation for modern transfusions.

为现代的输血手术 奠定了基础。

Up to this point, all transfusions had occurred in real time,

到了现在， 输血过程已经可以

directly between two individuals.

直接在两个个体之间实时传输了。

That’s because blood begins to clot almost immediately

因为当血接触了空气之后，

after coming into contact with air—

就会马上开始结块——

a defense mechanism to prevent excessive blood loss after injury.

一种用于避免受伤后 大量失血的防御机制。

In 1914, researchers discovered that the chemical sodium citrate

在 1914 年，研究者们发现 柠檬酸钠这种化学物质可以通过

stopped blood coagulating by removing the calcium necessary for clot formation.

去除血液凝结所必须的钙物质 来防止血液结块。

Citrated blood could be stored for later use—

柠檬酸钠血可被储存下来 供之后使用——

the first step in making large scale blood transfusions possible.

这使得大规模的 血液传输变得有希望了。

In 1916, a pair of American scientists found an even more effective anticoagulant

在 1916 年，两位美国科学家 发现了一种更有效的抗凝剂：

called heparin, which works by deactivating enzymes that enable clotting.

肝素，它可以灭活 会造成血凝结成块的酶。

We still use heparin today.

直到现在我们都在使用着肝素。

At the same time,

与此同时，

American and British researchers developed portable machines

美国与英国的研究人员 发明了便携式的机器

that could transport donor blood onto the battlefields of World War I.

用它甚至能将献血者的血 运往第一次世界大战的战场。

Combined with the newly-discovered heparin,

再加上新发现的肝素，

medics safely stored and preserved liters of blood,

救护人员能安全地 存储好几升的血，

wheeling it directly onto the battlefield to transfuse wounded soldiers.

将它推到前线战场 为受伤的士兵输血。

After the war, this crude portable box would become the inspiration

在战争结束后， 这种简略的便携式运血盒

为现代血库提供了灵感，

for the modern-day blood bank, a fixture of hospitals around the world.

现在血库已成为 世界各地医院的固定设施了。