Diagnosis by breath

The amount of certain molecules in human exhalation may be a sign of disease. The steam in the gas that people breathe out can store clues about your health, revealing more than just the food you have eaten.

In recent years, researchers have scrutinized the dew-filled compound to find evidence of diseases from sleep apnea to cancer.

Breathing may also reveal signs of frequent exposure to contaminants such as benzene and chloroform, which is a way to accurately measure the dose inside the body that may be missed if only contaminated air is sampled.

According to Joachin D. Pleil, an analytical chemist and an Environmental Protection Specialist at the US Environmental Protection Agency, 'Lungs are a muddy mess of pipes and bags with the task of exchanging gas. from blood to breath. Breath is the window to the blood. '

According to Pleil, the writer commented on breath analysis in the forthcoming edition of The Journal of Toxicology and Environment Health, Part B. The breath collection and analysis is slowly becoming a way of studying the body. softer, an addition to traditional ways such as blood and urine tests, or methods of infiltrating pain in the lungs.

'The patient may be a 90-year-old man on a ventilator, and it is difficult to get the circuit. Or an infant weighing 800g doesn't give enough urine for a week to analyze. But the child is always breathing. '

His breath contains more than 99% water - and is a mixture of many compounds.Scientists are trying to figure out how different molecules can play a sign of disease, such as lung cancer.(Photo: J. Korenblat)

Even ancient physicians know about the importance of breathing. Doctors examine the breath to find signs of illness from the time of Hippocrat. The sweet smell of acetone is a sign of diabetes, and severe liver disease is thought to make the breath smell fish. In breath, 99% is water, but approximately 3,000 other compounds are also detected in human breath - the average specimen contains at least 200. There are also pieces of DNA, protein, and fat floating in the mist. this.

While the research works on breath are being published at a dizzying speed (until now in 2008 there are more than 50 breath-related research articles), scientists still have to imagine Which molecules in the most important breath and which method of collection is best.

According to Rohit Katial, director of allergy and immune programs at the National Jewish Health Research and Research Center, Denver, 'It is not yet clear what we should look for - there are countless substances from A to Z. Breath is a source of curious specimens. But it's new in the early stages and the detection technique is still not ready. '

John Hunt, a respiratory specialist at Children's Hospital in Charlottesvill, University of Virginia, although the results are still ambiguous in some categories of research, breath analysis is a means of detecting certain diseases, eg pneumonia, reliable and painless. Breathing from the normal airway is slightly alkaline, pH is about 7.5, but a person with respiratory disease may have a pH of 3. 'Like putting lemon juice in your eyes.'

According to Hunt, the co-founder of a device manufacturing company to sample breath samples, the airway that causes this acidity may be an early sign of lung disease or lung transplantation. Severe asthma - a symptom group, not a disease - can be caused by a number of cellular stimulants, from virus infection to exposure to diesel exhaust. Analyzing breath samples can help distinguish whether acid spills cause irritation or contribute, helping doctors to prescribe drugs more effectively.

There is a general test for Helicobacter pylori , a stomach-causing bacterium that can cause ulcers. H. pylory has an enzyme that humans lack that breaks down urea. The patient drank a compound with urea from a heavy carbon isotope. If bacteria take up this substance, it breaks down the urea, and the heavy carbon isotope can be detected in the breath.

Scientists are studying volatile compounds in the breath to see if there is a good compound or a common pattern in people with certain types of cancer. Cancer cells produce other compounds compared to healthy cells - the researchers identified more than 20 of these volatiles. The papers were published in the previous fall of Cancer Biomarkers and in the March Clinica Chimica Acta, the researchers presented two analyzes comparing breath compounds of 193 lung cancer patients with 211 substances. control. Both models correctly identified lung cancer patients up to 84%.

According to Michael C. Madden, a poison expert with EPA, target molecules will determine the method of collection. Madden, Pleil and others have just published a new collection method in the Journal of Breath Reasearch. Techniques using existing tools - a 75-ml glass pump and a small test tube - can prepare and store multiple samples at the same time.

In general, sampling requires breathing into a collection tube with the power to play a trumpet or clarinet. Breathing 5 minutes will give 1ml of breath deposition. The samples are then covered, frozen if necessary and taken to the laboratory for analysis.

The analytical side is a lot of effort. 'That is the drawback. Many types of experiments are difficult to conduct. Easy for patients, but hard for the lab. "

Madden said they are expanding the scope of the study to include finding proteins produced by diseased cells. Lung cells attacked by pollutants can produce interleukin 8, a protein that takes advantage of immune system cells from the blood. For example, if hundreds of students are exposed to diesel emissions, breath analysis may reveal interleukin or cytokine, quickly understanding how the lungs of students are dealing with the attack.

Finally, Madden said, protein sets can be identified to indicate certain contact substances. 'If you look at 100 proteins, are there 10 outstanding proteins that are only available in factory emissions or 10 of ozone?' Better cooperation between medical doctors and environmental scientists will help promote that perspective.

Hunt stated, 'This is interesting and open to the field - an upcoming research tool and everyone has difficulty translating into the world of medicine. I think many things will happen within the next few years. Finally, we can smell how people are living. '