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什么时候死亡才是真正的死亡?对猪大脑的研究进一步证明,死亡是一个巨大的灰色区域
2019-05-02 土拨鼠之日 1335 0 0  

When is dead really dead? Study on pig brains reinforces that death is a vast gray area

什么时候死亡才是真正的死亡?对猪大脑的研究进一步证明,死亡是一个巨大的灰色区域



For the longest time, “death” used to be when the heart stopped beating and breathing stopped. Then, machines were invented in the 1930s that enabled people to receive air even if they could not take in the air themselves. In the 1950s, machines were developed to help sustain heartbeat.

在很长一段时间里,“死亡”通常用在心脏停止跳动和呼吸停止的时候。然后,20世纪30年代发明了机器,给不能自己吸入空气的人们传输空气。在20世纪50年代,帮助维持心跳的机器又被开发出来。

But no machine could bring back an irreversibly brain-damaged patient to have a functioning brain. As a result, the concept of “brain death” was introduced as an additional definition of death to complement death by heart-lung failure.

但没有任何机器能够让一个不可逆的脑损伤患者恢复正常的大脑功能。因此,“脑死亡”的概念作为对死亡的补充定义而被引入,以补充心肺功能衰竭所定义的死亡。

The concept of brain death, while legally adopted in the U.S. and in large parts of the world, has remained an area of ongoing discussion. It often centers on how someone can be dead when the heart is beating and the body is warm, even if this function is entirely reached through artificial support. Brain death also is more difficult to conceptualize, as it is a less visible form of death. And isn’t it so much easier to believe what we can see?

脑死亡的概念虽然在美国和世界大部分地区已经得到了合法采用,但仍是一个在持续讨论的领域。这个讨论的重点通常是一个人如何在心脏正常跳动,身体温暖的时候死去,即使这个体征完全是通过人工辅助实现的。脑死亡也很难概念化,因为它是一种不太可视化的死亡形式。相信我们所看到的要容易得多。

On April 17, 2019, a study published in Nature that showed signs of activity in pig brains after they were killed added more fuel to the discussion. I am a neurologist specializing in neurocritical care, with both clinical and research interests in acute brain damage, and broad exposure to catastrophic brain injury and brain death. My analysis of the study is that it reinforces much of what we already know, that death is a continuum.

2019年4月17日,发表在《自然》杂志上的一项研究又刺激了这一讨论。该研究显示,死后,猪的大脑出现了活动迹象。我是一名神经危重症的专科医师,对急性脑损伤的临床和研究都有兴趣,并广泛接触灾难性脑损伤和脑死亡。我对这项研究的分析是,它更加强调了我们已经知道的一件事——死亡是一个连续的过程。

When pigs die, can their brains be revived?
小标题: (猪死了之后,它们的大脑能复活吗?)

In the study, scientists took brains from pigs that had been slaughtered at USDA-regulated facilities, connected them to a machine that pumped an artificial blood-like nutritional fluid through the brains four hours after their “death,” and measured activity of brain cells. They found that even hours after death, blood circulation – or circulation of the artificial blood – and certain brain cell functions could be restored in this experimental setting.

在这项研究中,科学家们从在美国农业部监管的屠宰场中屠宰的猪身上提取了大脑,将它们与一台机器连接起来,在它们“死亡”四小时后,机器将一种类似血液的人工营养液注入它们的大脑,并测量了脑细胞的活动。他们发现,即使在死亡数小时后,血液循环——或者说人造血液的循环——和某些脑细胞功能也可以在这个实验环境中恢复。

The conclusion was that demise in the brain after the heart stops beating follows an extended process rather than occurring at a defined moment in time, and that perhaps our brains have a better capacity to heal than is currently known.
Is this news? Yes, on a scientific level – that is, under the microscope, because an experiment like this has not been done before. But, have we not known for a long time that death does not occur within the blink of an eye?

结论是,心脏停止跳动后,大脑的死亡是一个过程,而不是在某个特定的时间点发生,而且我们大脑的愈合能力可能比目前所认为的更好。
这是新闻吗?在科学的层面上(即在显微镜下)是,因为这样的实验以前从未做过。但是,难道我们一直不知道死亡并非发生在转眼之间吗?

Historic accounts of decapitated bodies vividly describe decapitated bodies taking a few steps or even running.
That means that such a body was not immediately dead. And, conceivably, if one hooked up such a body to blood supply and healed the wounds, most people could likely imagine that it could continue to be maintained with living body parts or cells.

历史记录中生动地描述了被斩首的身体走几步甚至跑几步的现象。
这意味着这个身体并没有立即死亡。而且,如果把这个身体与血液供应连接起来,并治愈了伤口,大多数人可能会想象,它可以继续凭活着的身体器官和细胞来维持生命。

Can a head still be alive after decapitation?
小标题: (斩首后的头还能活着吗?)

Even worse to imagine: Could the decapitated head still be conscious for a bit? Perhaps yes.
After the heart stops beating, we consider that someone has died. But, after the heartbeat stops, we also know that sometimes, the heartbeat can come back by itself. This is called autoresuscitation. In this case, someone that appeared dead for a few minutes may not have actually died.

想象一下: 这个被斩掉的脑袋还能清醒一会儿吗?也许可以。
当一个人的心脏停止跳动后,我们认为他死了。但是我们也知道,在停止之后,心跳有时候可以自己恢复。这叫做自动心肺复苏。在这种情况下,看上去已经死了几分钟的人可能实际上并没有死。

But the situation is different for the brain than for the heart. When there is a lack of blood flow in the absence of a heart that pumps it, or when there is intrinsic brain injury and blood cannot get in, the situation is tricky. Brains are very sensitive to being deprived of oxygen and energy supply, and various degrees of brain injury occur. Depending on how long the energy fuel to the brain is absent, brain function can remain alive to various degrees and be rekindled to a degree we neuroscientists do not yet fully know. We know that brain function is seriously disturbed, with variable permanence of function loss depending on how long the brain has not had energy.

但是大脑和心脏的情况不同。当没有心脏泵血,血液无法流动时,或者当有内在的脑损伤,血液无法进入时,情况就很棘手了。大脑对缺氧和缺少能量供应非常敏感,这会导致不同程度的脑损伤。根据大脑缺少能量供应的时间长短,大脑功能可以在不同程度上得以保持,并可以在某种程度上(具体的程度我们神经学家还不完全清楚)被重新激活。我们知道,大脑功能受到严重干扰,功能丧失的持续时间取决于大脑缺少能量的时间长短。

The end result of how functional such a damaged brain will come out is one of the biggest challenges we have to learn more about.
After an injury, a whole sequence of consecutive processes occurs that is called secondary brain injury and is triggered by the insult to the brain in the first place. And these processes often cause tremendous damage, and sometimes more than the actual first injury.

大脑受损后的功能如何,是我们需要去了解的最大挑战之一。
大脑受伤后,一系列连续的过程发生,这被称为继发性脑损伤。这一过程通常会造成巨大的伤害,有时甚至比第一次伤害还要严重。

For example, a hard blow to the head can result in a bruise or bleeding in the brain, which can be removed by surgery in certain cases. Despite the bleeding being stopped or removed, however, the surrounding brain will sometimes start swelling and bruising even more over the subsequent days, like a big bruise on the thigh goes through stages and color changes. There is not yet a preventive therapy for this, but we know that some factors can make this process worse, such as blood pressure that is too low or lack of oxygen to the brain during the healing phase.

例如,头部受到重击可能导致脑部瘀伤或出血,在某些情况下瘀伤可以通过手术移除。然而,尽管停止出血,但在接下来的几天里,周围的大脑有时会开始肿胀和瘀伤,甚至会更严重,就像大腿上的大瘀伤会经历不同阶段,颜色也会发生变化。目前还没有针对这种情况的预防方法,但我们知道,一些因素(比如血压过低,或者在康复阶段大脑缺氧)会使这一过程的后果变得更严重。

Imagine a broken bone: The cast is just the first step, and there is swelling, pain and weakness for weeks to come. In the brain, the process is more granular. And in neuroscience, we are just now beginning to understand this cascade of events.

想象一下骨折的情况:石膏只是第一步,接下来的几周会有肿胀、疼痛和虚弱。在大脑中,这个过程会更加细化。我们神经科学现在才刚刚开始了解这一连串的过程。

What to learn from the pig study
小标题: (从对猪的研究中学到什么)

The study of revived pig brain cells does not even come close to touching on this much bigger picture. It is limited to showing that the time span and spectrum of nerve cell function that can persist and at least partially be restored is longer than had been shown so far. Hence, it supports the idea that dying is a process, and puts an additional piece of data on the length of this process.

对再生的猪脑细胞的研究甚至都没有触及到更深层次的东西。它仅仅表明了神经细胞的功能可以在更广的时间跨度下保持并至少部分恢复。因此,它支持了死亡是一个过程的观点,并增加了这个过程的长度。

But it does not show that these brain cells were able to function as a nerve cell network leading to higher brain function such as consciousness or awareness – the features that set us apart as humans. It also just looks at the immediate restoring of cell function, and not at how these brains do days out, when the continuing processes of secondary brain damage set in.

但这并不表明这些脑细胞能够像神经细胞网络一样运作,神经网络细胞能够产生更高的大脑功能,如认知和意识——这些特征使我们人类有别于其他生物。这个实验也只是观察脑细胞功能的立即恢复,而不是观察这些大脑在继发性脑损伤开始时是如何工作的。

To summarize, in the absence of blood flow, the brain, including all its individual cells will die – eventually. And this study has perhaps expanded the understanding of “eventually.”
Death is a process, and not a moment in time. It is the human desire to put things in categories of black and white, and to have definitions that let us operate in daily life. Death – this is becoming more and more clear – is a large gray zone, and we will have to expect that this gray zone grows as science progresses.

总而言之,在没有血液流动的情况下,大脑,包括它所有的细胞,最终都会死亡。这项研究也许扩展了对“最终”的理解。
死亡是一个过程,而不是一个瞬间。人类希望把事物按非黑即白的方式分类,并给出一个确切的定义。而死亡是一个巨大的灰色地带,这一点变得越来越明显,我们期待这个灰色地带会随着科学的进步而变得更明了。

(评论部分)

robin wallace
This sheds new light on the South American culture that keeps their dead around the house for months, and continues to clothe and “feed” them once moved to the crypt.

这让人们对南美文化有了新的认识——在南美文化中人们让死者在家里呆上几个月,并在把他们搬到地窖后继续给他们穿衣和“喂食”。

On another note, do you really think awareness and consciousness set us apart as humans? I would think as a neuroscientist, you’d be more likely to suggest that those two conditions are also a gray zone, or continuum, where some animals are more and some are less. Especially since you can’t point to a structure in a human brain that awareness and consciousness reside in that animal brains don’t have. And in that light, the pig slaughterhouse is even more ghastly and cruel a place than I thought. I wish scientists like you would advocate for kinder practices, such as no high speed slaughter.

另一方面,你真的认为认知和意识把我们人类跟其他生物分开了吗?我认为,作为一名神经学家,你更应该说这两个东西也是灰色地带,有些动物多一些,有些动物少一些。尤其是当你没法指出人类大脑中认知和意识所在的哪个区域是动物大脑中所没有的。从这个角度来看,屠宰场比我想象的还要可怕和残忍。我希望像你这样的科学家能提倡更仁慈的做法,比如禁止高速屠宰。

Sharwan kumar
Thanks for your views.
Katharina BuslAssociate Professor, Neurology. Chief, Division of Neurocritical Care, Department of Neurology, University of FloridaIn reply to robin wallace Refers to living versus dead humans. not humans versus animals.

谢谢你的意见。
佛罗里达大学神经内科神经重症医学部主任,神经学副教授凯瑟琳娜·巴斯,与罗宾·华莱士讨论过关于活人与死人的问题,不是人和动物的问题。

There is no point in answering around the question. All animals whether pigs or humans are animals and are equivalent- neither being inferior or superior. All animals have feelings, pigs may not speak and cry in the language of human beings when decapitated by the animals who call themselves humans. What if Katharine Busls were decapitated for carrying out the type of experiments you describe and comment herein and robin wallace were to comment upon that the way he has done? I am hopeful that you would appreciate that as a true student of neuroscience.Now as for the inferences from the experiments done on the pigs are concerned, that does not make any difference to humans. Moreover, experiments that too in large numbers are needed to be done on human animals rather than on animals other than humans. Best wishes and regards.

回避这个问题是没有意义的。所有的动物,无论是猪还是人,只要是动物,就都是平等的——没有优劣之分。所有动物都有感情,猪被自称为人类的动物斩首时,可能不会用人类的语言诉说和哭泣。如果凯瑟琳·巴斯因为做了你在这里描述和评论的实验或是罗宾·华莱士因为像原来一样评论而被斩首的话,又会怎么样呢?你应该庆幸自己是一名真正的神经科学学生。现在,在猪身上做的实验中得出的推论,对人类没有任何意义。应该在人类身上进行大量的实验,而不是在其他动物身上进行。致以最诚挚的祝愿和问候。

Hugo Pottisch
Studies on pigs show that scientist lack basic empathy and would hence not gain much quality of living if they did live longer.

对猪的研究表明,科学家缺乏基本的同理心,因此,即使他们活得更长,也没法有效提高生活质量。

——————分割线——————

Paul Smith(楼主)
Perhaps they can do something for the democrats. They appear to be brain dead.

也许他们能为民主党做些什么。他们似乎是脑死亡患者。

Joe Dirk(回复楼主)
If you cannot make a meaningful contribution to the conversation please refrain from commenting.This site is for academic learning, not quips and slander.

如果你不能对交谈做出有意义的贡献,请不要发表评论。这个网站是为了学术学习,而不是俏皮话和诽谤。