呼吸测定仪能探测癌症吗?- 朱利安 · 波茨卡 Julian Burschka: Could a breathalyzer detect cancer?

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演员: Julian Burschka


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How is it that a breathalyzer can measure the alcohol content in someone’s blood,
体内酒精检测仪到底是怎样
hours after they had their last drink, based on their breath alone?
单凭人们的呼吸
Exhaled breath contains trace amounts of hundreds, even thousands,
就能检测饮酒几小时后的
of volatile organic compounds:
血液里的酒精含量?
small molecules lightweight enough to travel easily as gases.
呼出的气息里包含着 成百上千的
One of these is ethanol, which we consume in alcoholic drinks.
挥发性有机化合物:
It travels through the bloodstream to tiny air sacs in the lungs,
这些质量极轻的小分子, 被呼吸带了出来。
passing into exhaled air at a concentration 2,000 times lower,
其中包含着我们从酒精饮料中摄取的乙醇。
on average, than in the blood.
它随着血流被输送到肺部的微小气囊中,
When someone breathes into a breathalyzer,
然后再被呼出, 这时乙醇的平均浓度
the ethanol in their breath passes into a reaction chamber.
是血液中的 1/2000 。
There, it’s converted to another molecule, called acetic acid,
当一个人向检测仪呼气时,
in a special type of reactor that produces an electric current during the reaction.
呼吸中的乙醇进入到一个反应器中。
The strength of the current indicates the amount of ethanol
在那儿,它被转化成了另一种分子, 那就是醋酸,
in the sample of air, and by extension in the blood.
在这个特别的反应器里, 一股电流在反应中产生了。
In addition to the volatile organic compounds like ethanol
电流的强度反映了气息中乙醇的浓度
we consume in food and drink,
然后通过估算可得出血液里的乙醇浓度。
the biochemical processes of our cells produce many others.
除了我们从饮食中摄取的
And when something disrupts those processes, like a disease,
像乙醇这样的挥发性有机化合物,
the collection of volatile organic compounds in the breath
人体细胞的生化反应 还产生去许多其他的物质。
may change, too.
当这些反应受到干扰时, 比如疾病,
So could we detect disease by analyzing a person’s breath,
呼吸中包含的挥发性有机化合物
without using more invasive diagnostic tools
可能也会改变。
like biopsies, blood draws, and radiation?
因此,我们是否可以通过分析人体的呼吸 来检测疾病,
In theory, yes,
从而避免使用更具侵入性的诊断工具,
but testing for disease is a lot more complicated than testing for alcohol.
例如活组织切片、抽血和放射扫描呢?
To identify diseases,
理论上来说,行得通。
researchers need to look at a set of tens of compounds in the breath.
但是检测疾病可比检测酒精浓度复杂多了。
A given disease may cause some of these compounds
为了识别病症,
to increase or decrease in concentration, while others may not change—
研究人员需要检测 数十种呼吸中所含的化合物。
the profile is likely to be different for every disease,
某种特定疾病可能导致某些化合物
and could even vary for different stages of the same disease.
数量上的增加或减少, 同时并不影响其他化合物——
For example, cancers are among the most researched candidates
而不同疾病造成的这类数量影响 也各有区别,
for diagnosis through breath analysis.
甚至同一种疾病的各个阶段 也会产生不同影响。
One of the biochemical changes many tumors cause
比如,癌症是运用呼吸分析的诊断方法
is a large increase in an energy-generating process
最广泛的疾病之一。
called glycolysis.
肿瘤会造成众多生化反应改变,
Known as the Warburg Effect,
其中之一,是一种能量产出反应的大幅增加,
this increase in glycolysis results in an increase of metabolites like lactate
被称为“糖酵解”。
which in turn can affect a whole cascade of metabolic processes
也称“瓦氏效应”,
and ultimately result in altered breath composition,
糖酵解的增加导致代谢物增加, 比如产生大量乳酸,
possibly including an increased concentration of volatile compounds
这反过来影响了一系列的新陈代谢反应,
such as dimethyl sulfide.
最终改变了呼吸中的化合物组成,
But the Warburg Effect is just one potential indicator of cancerous activity,
某些挥发性化合物可能会大量聚集,
and doesn’t reveal anything about the particular type of cancer.
例如二甲基硫醚。
Many more indicators are needed to make a diagnosis.
但是瓦氏效应仅仅是 癌性活动的一个可能性指标,
To find these subtle differences,
并且不能揭示癌症的具体种类。
researchers compare the breath of healthy people
想要确诊, 还需要获得许多其他的指标。
with the breath of people who suffer from a particular disease
为了明确这些细微差别,
using profiles based on hundreds of breath samples.
研究人员向健康者的呼吸样本
This complex analysis requires a fundamentally different,
与罹患某种特定疾病的人的呼吸样本
more versatile type of sensor from the alcohol breathalyzer.
进行数百次的比对。
There are a few being developed.
完成这一复杂的分析过程所需的探测器,
Some discriminate between individual compounds
比酒精测定仪更加全能。
by observing how the compounds move through a set of electric fields.
人们正在研发一些这样的机器。
Others use an array of resistors made of different materials
有的通过观察化合物们 经过一系列电场的路径,
that each change their resistance when exposed to a certain mix
辨别出不同的化合物。
of volatile organic compounds.
有的利用一组由不同材料制成的电阻器,
There are other challenges too.
通过观测每种电阻器在接触 挥发性有机化合物的混合物时,
These substances are present at incredibly low concentrations—
其阻力发生的变化, 来进行辨别。
typically just parts per billion,
这一过程困难重重。
much lower than ethanol concentrations in the breath.
这些化合物的浓度极低,
Compounds’ levels may be affected by factors other than disease,
通常只有十亿分之一,
including age, gender, nutrition, and lifestyle.
这可比呼吸中乙醇的浓度低多了。
Finally, there’s the issue
化合物的数量水平 同时还受到其他因素的影响
of distinguishing which compounds in the sample
包括年龄、性别、 营养状况和生活方式。
were produced in the patient’s body
最后,要在取得样本后,
and which were inhaled from the environment
快速分辨其中有哪些化合物
shortly before the test.
来自于患者体内,
Because of these challenges, breath analysis isn’t quite ready yet.
哪些来源于外界,
But preliminary clinical trials on lung, colon,
也颇具挑战。
and other cancers have had encouraging results.
基于这些困难与挑战, 利用呼吸分析疾病的技术还很不成熟。
One day, catching cancer early might be as easy as breathing in and out.
即便如此,基于肺癌、结肠癌