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March20 podcast Dr Hazen
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MEBO - UBIOME study 2018



MEBO Gut Microbiome Study
"Microbial Basis of Systemic Malodor and PATM Conditions (PATM)"
Funded by uBiome Research Grant

"Microbial Basis of Systemic Malodor and PATM Conditions (PATM)"

Dynamics of the Gut Microbiota in
Idiopathic Malodor Production

Started May 2018 - Ongoing

Current people sent kits : 100/100
3 kits per person


Participation info : LINK English

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TMAU Petition world
TMAU UK end total:262
TMAU UK ends 23/01/20
TMAU Petition USA end total 204
USA : Moveon open
TMAU (Dominican)
Metabolomic Profiling Study

Start : Aug 2016
Stage 1 : 27 Canadian volunteers to test
Latest click here (26 oct) :
17 samples returned

Note : Stage 1 is Canada only.
Return cut-off date : passed
Analysis can take 6/8 weeks
Analysis start in/before Nov
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Blog Archive

MEBO Research Clinical Trials

Click here to read details of the MEBO Clinical Trials
NCT03582826 - Ongoing not recruiting
Microbial Basis of Systemic Malodor and PATM Conditions (PATM)
United States 2018 - ongoing

NCT02683876 - Completed
Exploratory Study of Relationships Between Malodor and Urine Metabolomics
Canada and United States 2016 - ongoing

NCT03451994 - Completed
Exploratory Study of Volatile Organic Compounds in Alveolar Breath
United Kingdom and United States 2013 - ongoing

NCT02692495 - Completed
Evaluation of Potential Screening Tools for Metabolic Body Odor and Halitosis
United Kingdom 2009 - 2012

Wednesday, September 7, 2011

What VOCS cause the odor of feces ?

What makes up the smell of feces ?
There has to be a good chance that there is no overwhelmingly agreed list of what volatile organic compounds make up the odor of feces, given how our research systems are set up. It's the kind of research which would probably be overlooked. This paper from 1987 was an attempt to define what VOCs made the 'fecal odor' and gave an interesting list. However case studies like these should not be regarded as correct or generally agreed by researchers. It's not until the evidence is overwhelming that conclusions are accepted.

1987 paper says the methyl sulfides methanethiol, dimethyl disulfide and dimethyl trisulfide 
The paper came to the conclusion that the odor of feces was mainly caused by the methyl sulfides methanethiol, dimethyl disulfide, and dimethyl trisulfide. We have been unable to confirm if these make good FMO3 substrates but a suspicion is that they are. Dr Cashman said in his interview in the blog that dimethyl disulfide was a good FMO3 substrate. A guess would be the 2 other methyl sulfides are too. This is not evidence of anything, merely pointing out that they are probably good FMO3 substrates.

Only Trimethylamine has no alternative route
It should be remembered that enzymes are set up to deal with changing chemical compounds of certain structures, but that usually if they cannot be metabolized by that enzyme then they can go through another enzyme less suited to metabolizing them. The only exception for FMO3 is trimethylamine, which is why researchers currently think only this causes an odor in someone with a compromised FMO3 enzyme.

Gas-chromatographic and mass-spectrometric analysis of the odor of human feces.Moore JG, Jessop LD, Osborne DN.
Department of Medicine, Salt Lake Veterans Administration, Medical Center, Utah 84148.
Gas-chromatographic and mass-spectrometric analysis of human fecal samples was performed to identify the volatile compounds responsible for fecal odor. The compounds identified with fecal odor were the methyl sulfides methanethiol, dimethyl disulfide, and dimethyl trisulfide. Skatole and indole, the benzopyrrole volatiles believed to be responsible for fecal odor, in fact elaborated a napthalenelike "mothball" odor in the crystalline state as well as after purging from feces. A small amount of hydrogen sulfide gas was also identified in fecal samples. The components responsible for fecal odor are complex and may be influenced by dietary and endogenous contributions. However, the major components are methyl sulfide compounds rather than skatole and indole as is currently believed.


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