Showing posts with label breath test. Show all posts
Showing posts with label breath test. Show all posts

Saturday, April 13, 2024

Exhale The Difference: Propylene Oxide as a Game-Changer in Identifying Idiopathic Malodor Conditions

A new study posted on MedrXiv sheds light on the potential of breath analysis as a powerful, non-invasive diagnostic tool for Trimethylaminuria (TMAU) and TMAU-like conditions. One of the most interesting observations is the detection of Propylene Oxide in exhaled breath suggesting its delayed elimination and offering a promising marker for misunderstood and underdiagnosed conditions.

TMAU-like (yet negative to choline-challenge-based test) and "People Are Allergic To Me" (PATM) conditions, characterized by the emission of odorous or irritating Volatile Organic Compounds (VOCs), have long challenged the medical community due to the lack of non-challenge-based diagnostic procedures.

Using advanced gas chromatography-mass spectrometry, researchers analyzed the breath of 23 individuals exhibiting TMAU-like symptoms. They discovered that Propylene Oxide, alongside other VOCs, some of which were previously associated with PATM, can effectively discriminate between individuals who have tested positive for TMAU at some point and those who have not. This method demonstrated impressive accuracy, precision, and recall rates, making it a potential cornerstone for future diagnostic strategies.

Propylene Oxide's presence in breath samples particularly stood out in the study. This compound was more abundant in individuals that never tested positive for TMAU, potentially pointing to unique metabolic processes or environmental interactions that could be pivotal in understanding and managing TMAU-like conditions.

Propylene Oxide (PO) is a prevalent chemical found not only on Earth, owing to its widespread use in industrial and consumer applications, but also in the Milky Way. It leaves more significant marks on the human body than previously thought. Mass production contributes to its omnipresence, and exposure can occur through various sources such as cellulose acetate film, wood shavings, and paper cups. Despite efforts to eliminate gas residues, accidental exposure still occurs, particularly among workers involved in sterilization processes. Additionally, foods treated with PO as a fumigant may contain residues of the chemical.

PO has been detected in human breath following exposure to Propylene (PE), a combustion product found in forest fires, cigarette smoke, and vehicle exhaust. Indoor exposure is typically higher than outdoors due to residential activities like cooking, and urban areas tend to have higher concentrations than rural regions. Workers in specific industries may face elevated exposure levels, such as firefighters and refinery plant operators. PEG in cosmetic products can also be contaminated with propylene oxide. Furthermore, Propylene Glycol (PG) in cigarettes and e-liquids can be converted to PO, contributing to exposure.

Other compounds mentioned in the paper were markers of oxidative stress Hydroperoxide, hexyl; Hexanal; Decane, 2-methyl-; Tetradecane; Decane, 2,6,6-trimethyl- and D-limonene2,2,3-trimethylnonane was one of compounds associated with breath odor. 

This research emphasizes the need for personalized diagnostic approaches, considering the significant variability in VOCs among individuals. Such tailored strategies could lead to more accurate diagnoses and better management of conditions that currently lack specific treatments.




REFERENCES

Irene S. Gabashvili 2024 Propylene Oxide in Exhaled Breath as a Marker for Discriminating TMAU-like Conditions from TMAU medRxiv 2024.04.11.24305677; doi: https://doi.org/10.1101/2024.04.11.24305677

Irene S. Gabashvili 2024 Biological Factors Influencing Individual Responses to Propylene Oxide: A Systematic Review of Exogenous Exposure, Endogenous Production and Detoxification
medRxiv 2024.02.15.24302622; doi: https://doi.org/10.1101/2024.02.15.24302622

Friday, June 28, 2013

I Know What You Ate This Summer

Despite active foodstagramming and foodteresting, and eagerness to show pictures of meals and diet reports to friends on social media, we don't really want others to know everything we eat. But they might know anyway.

Why worry about NSA, when Google, Facebook, Amazon and many others know what we might be eating. Cameras record our ways to groceries and restaurants, credit cards record our purchases, food chains know our weaknesses, clothes shops know how, as a result, our pant sizes change over time. One day phones will know what we ate too.  As both short- and long-term diets change our breath-prints - creating signature metabolites in exhaled breath.

A recent Dutch study actually looked at what gluten-free eating does to our breath. Just 4 week of dieting lead to remarkable - though reversible -  differences. (As detected in 20 healthy individuals by gas chromatography coupled with mass spectrometry (TD-GC-tof-MS) in combination with chemometric analysis ). A set of twelve volatile compounds that distinguish gluten-free eaters along with information from Aurametrix knowledgebase is listed in the table below.


Compound Odor Notes
2-butanol strong alcoholic 1-Butanol smells like permanent marker (Sharpie) 
octane Gasoline-like, car exhaust octyl chloride smells faintly of oranges
2-propyl-1 pentanol green banana 1-Pentanol smells like paint thinner 
nonanal strong fruity or floral attracts mosquitoes
dihydro-4-methyl-2(3H)-furanone strong coconut aroma 5-butyl-4-methyloxolan-2-one is known as "whisky lactone"
nonanoic acid rancid beer, old cooking oil armpits of males over 30
dodecanal Soapy, waxy, aldehydic, citrus, orange rindy with floral nuances Pure, synthetic qualities of this fatty aldehyde are used in traces in perfumery for "fresh laundry"-like effects.


Reference
Baranska A, Tigchelaar E, Smolinska A, Dallinga JW, Moonen EJ, Dekens JA, Wijmenga C, Zhernakova A, & van Schooten FJ (2013). Profile of volatile organic compounds in exhaled breath changes as a result of gluten-free diet. Journal of breath research, 7 (3) PMID: 23774130