[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:06.79,0:00:11.72,Default,,0000,0000,0000,,How is it that a breathalyzer can measure \Nthe alcohol content in someone’s blood,
Dialogue: 0,0:00:11.72,0:00:16.34,Default,,0000,0000,0000,,hours after they had their last drink, \Nbased on their breath alone?
Dialogue: 0,0:00:16.34,0:00:20.89,Default,,0000,0000,0000,,Exhaled breath contains trace amounts \Nof hundreds, even thousands,
Dialogue: 0,0:00:20.89,0:00:23.35,Default,,0000,0000,0000,,of volatile organic compounds:
Dialogue: 0,0:00:23.35,0:00:27.84,Default,,0000,0000,0000,,small molecules lightweight enough \Nto travel easily as gases.
Dialogue: 0,0:00:27.84,0:00:32.43,Default,,0000,0000,0000,,One of these is ethanol, \Nwhich we consume in alcoholic drinks.
Dialogue: 0,0:00:32.43,0:00:36.41,Default,,0000,0000,0000,,It travels through the bloodstream \Nto tiny air sacs in the lungs,
Dialogue: 0,0:00:36.41,0:00:41.15,Default,,0000,0000,0000,,passing into exhaled air \Nat a concentration 2,000 times lower,
Dialogue: 0,0:00:41.15,0:00:43.41,Default,,0000,0000,0000,,on average, than in the blood.
Dialogue: 0,0:00:43.41,0:00:45.82,Default,,0000,0000,0000,,When someone breathes \Ninto a breathalyzer,
Dialogue: 0,0:00:45.82,0:00:49.86,Default,,0000,0000,0000,,the ethanol in their breath \Npasses into a reaction chamber.
Dialogue: 0,0:00:49.86,0:00:53.89,Default,,0000,0000,0000,,There, it’s converted to another molecule,\Ncalled acetic acid,
Dialogue: 0,0:00:53.89,0:00:58.91,Default,,0000,0000,0000,,in a special type of reactor that produces\Nan electric current during the reaction.
Dialogue: 0,0:00:58.91,0:01:02.02,Default,,0000,0000,0000,,The strength of the current \Nindicates the amount of ethanol
Dialogue: 0,0:01:02.02,0:01:05.75,Default,,0000,0000,0000,,in the sample of air, \Nand by extension in the blood.
Dialogue: 0,0:01:05.75,0:01:08.93,Default,,0000,0000,0000,,In addition to the volatile \Norganic compounds like ethanol
Dialogue: 0,0:01:08.93,0:01:11.04,Default,,0000,0000,0000,,we consume in food and drink,
Dialogue: 0,0:01:11.04,0:01:14.88,Default,,0000,0000,0000,,the biochemical processes of our cells \Nproduce many others.
Dialogue: 0,0:01:14.88,0:01:18.47,Default,,0000,0000,0000,,And when something disrupts \Nthose processes, like a disease,
Dialogue: 0,0:01:18.47,0:01:21.76,Default,,0000,0000,0000,,the collection of volatile \Norganic compounds in the breath
Dialogue: 0,0:01:21.76,0:01:23.62,Default,,0000,0000,0000,,may change, too.
Dialogue: 0,0:01:23.62,0:01:27.60,Default,,0000,0000,0000,,So could we detect disease \Nby analyzing a person’s breath,
Dialogue: 0,0:01:27.60,0:01:30.40,Default,,0000,0000,0000,,without using more invasive \Ndiagnostic tools
Dialogue: 0,0:01:30.40,0:01:34.05,Default,,0000,0000,0000,,like biopsies, blood draws, and radiation?
Dialogue: 0,0:01:34.05,0:01:35.83,Default,,0000,0000,0000,,In theory, yes,
Dialogue: 0,0:01:35.83,0:01:40.72,Default,,0000,0000,0000,,but testing for disease is a lot more \Ncomplicated than testing for alcohol.
Dialogue: 0,0:01:40.72,0:01:42.34,Default,,0000,0000,0000,,To identify diseases,
Dialogue: 0,0:01:42.34,0:01:46.80,Default,,0000,0000,0000,,researchers need to look at a set \Nof tens of compounds in the breath.
Dialogue: 0,0:01:46.80,0:01:49.63,Default,,0000,0000,0000,,A given disease may cause \Nsome of these compounds
Dialogue: 0,0:01:49.63,0:01:54.33,Default,,0000,0000,0000,,to increase or decrease in concentration, \Nwhile others may not change—
Dialogue: 0,0:01:54.33,0:01:57.62,Default,,0000,0000,0000,,the profile is likely to be different \Nfor every disease,
Dialogue: 0,0:01:57.62,0:02:01.49,Default,,0000,0000,0000,,and could even vary for different stages \Nof the same disease.
Dialogue: 0,0:02:01.49,0:02:05.28,Default,,0000,0000,0000,,For example, cancers are among \Nthe most researched candidates
Dialogue: 0,0:02:05.28,0:02:07.93,Default,,0000,0000,0000,,for diagnosis through breath analysis.
Dialogue: 0,0:02:07.93,0:02:10.93,Default,,0000,0000,0000,,One of the biochemical changes \Nmany tumors cause
Dialogue: 0,0:02:10.93,0:02:14.40,Default,,0000,0000,0000,,is a large increase \Nin an energy-generating process
Dialogue: 0,0:02:14.40,0:02:16.50,Default,,0000,0000,0000,,called glycolysis.
Dialogue: 0,0:02:16.50,0:02:18.42,Default,,0000,0000,0000,,Known as the Warburg Effect,
Dialogue: 0,0:02:18.42,0:02:24.17,Default,,0000,0000,0000,,this increase in glycolysis results \Nin an increase of metabolites like lactate
Dialogue: 0,0:02:24.17,0:02:28.34,Default,,0000,0000,0000,,which in turn can affect a whole cascade \Nof metabolic processes
Dialogue: 0,0:02:28.34,0:02:31.79,Default,,0000,0000,0000,,and ultimately result \Nin altered breath composition,
Dialogue: 0,0:02:31.79,0:02:36.32,Default,,0000,0000,0000,,possibly including an increased \Nconcentration of volatile compounds
Dialogue: 0,0:02:36.32,0:02:38.75,Default,,0000,0000,0000,,such as dimethyl sulfide.
Dialogue: 0,0:02:38.75,0:02:43.28,Default,,0000,0000,0000,,But the Warburg Effect is just one \Npotential indicator of cancerous activity,
Dialogue: 0,0:02:43.28,0:02:47.30,Default,,0000,0000,0000,,and doesn’t reveal anything \Nabout the particular type of cancer.
Dialogue: 0,0:02:47.30,0:02:51.16,Default,,0000,0000,0000,,Many more indicators are needed \Nto make a diagnosis.
Dialogue: 0,0:02:51.16,0:02:52.97,Default,,0000,0000,0000,,To find these subtle differences,
Dialogue: 0,0:02:52.97,0:02:55.84,Default,,0000,0000,0000,,researchers compare the breath \Nof healthy people
Dialogue: 0,0:02:55.84,0:02:59.01,Default,,0000,0000,0000,,with the breath of people \Nwho suffer from a particular disease
Dialogue: 0,0:02:59.01,0:03:02.36,Default,,0000,0000,0000,,using profiles based on hundreds \Nof breath samples.
Dialogue: 0,0:03:02.36,0:03:06.09,Default,,0000,0000,0000,,This complex analysis \Nrequires a fundamentally different,
Dialogue: 0,0:03:06.09,0:03:10.15,Default,,0000,0000,0000,,more versatile type of sensor \Nfrom the alcohol breathalyzer.
Dialogue: 0,0:03:10.15,0:03:12.20,Default,,0000,0000,0000,,There are a few being developed.
Dialogue: 0,0:03:12.20,0:03:15.07,Default,,0000,0000,0000,,Some discriminate \Nbetween individual compounds
Dialogue: 0,0:03:15.07,0:03:19.30,Default,,0000,0000,0000,,by observing how the compounds move \Nthrough a set of electric fields.
Dialogue: 0,0:03:19.30,0:03:22.66,Default,,0000,0000,0000,,Others use an array of resistors \Nmade of different materials
Dialogue: 0,0:03:22.66,0:03:26.62,Default,,0000,0000,0000,,that each change their resistance \Nwhen exposed to a certain mix
Dialogue: 0,0:03:26.62,0:03:29.16,Default,,0000,0000,0000,,of volatile organic compounds.
Dialogue: 0,0:03:29.16,0:03:30.94,Default,,0000,0000,0000,,There are other challenges too.
Dialogue: 0,0:03:30.94,0:03:34.87,Default,,0000,0000,0000,,These substances are present \Nat incredibly low concentrations—
Dialogue: 0,0:03:34.87,0:03:37.21,Default,,0000,0000,0000,,typically just parts per billion,
Dialogue: 0,0:03:37.21,0:03:40.40,Default,,0000,0000,0000,,much lower than ethanol concentrations \Nin the breath.
Dialogue: 0,0:03:40.40,0:03:44.29,Default,,0000,0000,0000,,Compounds’ levels may be affected \Nby factors other than disease,
Dialogue: 0,0:03:44.29,0:03:48.74,Default,,0000,0000,0000,,including age, gender, nutrition, \Nand lifestyle.
Dialogue: 0,0:03:48.74,0:03:50.06,Default,,0000,0000,0000,,Finally, there’s the issue
Dialogue: 0,0:03:50.06,0:03:52.67,Default,,0000,0000,0000,,of distinguishing which compounds \Nin the sample
Dialogue: 0,0:03:52.67,0:03:54.66,Default,,0000,0000,0000,,were produced in the patient’s body
Dialogue: 0,0:03:54.66,0:03:57.05,Default,,0000,0000,0000,,and which were inhaled \Nfrom the environment
Dialogue: 0,0:03:57.05,0:03:59.29,Default,,0000,0000,0000,,shortly before the test.
Dialogue: 0,0:03:59.29,0:04:03.66,Default,,0000,0000,0000,,Because of these challenges, \Nbreath analysis isn’t quite ready yet.
Dialogue: 0,0:04:03.66,0:04:06.76,Default,,0000,0000,0000,,But preliminary clinical trials \Non lung, colon,
Dialogue: 0,0:04:06.76,0:04:10.59,Default,,0000,0000,0000,,and other cancers \Nhave had encouraging results.
Dialogue: 0,0:04:10.59,0:04:16.63,Default,,0000,0000,0000,,One day, catching cancer early \Nmight be as easy as breathing in and out.