| Title: | Process for detecting Helicobacter pylori using aliphatic amides |
| Author(s): | Ferreira JA; Dias E; Rocha SM; Coimbra MA; |
| Address: | "QOPNA, Department of Chemistry, University of Aveiro, Campus de Santiago, Aveiro, Portugal" |
| DOI: | 10.1007/s00216-011-5259-x |
| ISSN/ISBN: | 1618-2650 (Electronic) 1618-2642 (Linking) |
| Abstract: | "Helicobacter pylori diagnosis is fundamental in the management of gastrointestinal pathologies, whose current clinical guidelines support a non-invasive 'test-and-treat' strategy. As such, the present work reports the basis of a new, low-cost, specific breath test based on the detection of volatile carboxylic acids resulting from the hydrolysis of short-chain aliphatic amides by H. pylori amidases. Propionamide and butyramide, which are metabolized by amidases to propionic and butyric acids, were elected for this study. Conditions for the extraction of these acids from a vapour phase were optimized concerning the use of solid-phase microextraction (SPME) followed by gas chromatography-quadrupole mass spectrometry (GC-qMS) analysis. SPME-GC-qMS was then used to detect the acids released into a vapour phase upon incubation of a H. pylori reference strain J99 or a clinical specimen with the amides. These experiments have demonstrated that the administration of less than 9 mg of propionamide and/or butyramide to H. pylori cultures, in loads recognized to cause infection (10(6)-10(9) cells), resulted in the formation of detectable and/or quantifiable amounts of propionic and/or butyric acids after 30 min incubation. As such, propionic and butyric acids can be used as biomarkers for H. pylori upon incubation with the corresponding amides. SPME-GC-qMS was also used to verify the hepatic stability of the acids. These experiments were conducted in mouse liver cells and revealed no signs of metabolization that could compromise their bioavailability in future in vivo assays. Moreover, SPME-GC-qMS permitted the detection of both acids in amounts as low as 0.8 mug in systems mimicking exhaled breath, demonstrating the sensitivity of the method for these compounds" |
| Keywords: | Amides/metabolism Amidohydrolases/metabolism Breath Tests/*methods Calibration Carboxylic Acids/*analysis/metabolism Gas Chromatography-Mass Spectrometry/methods Helicobacter Infections/*diagnosis Helicobacter pylori/enzymology/*isolation & purification H; |
| Notes: | "MedlineFerreira, Jose A Dias, Elsa Rocha, Silvia M Coimbra, Manuel A eng Evaluation Study Research Support, Non-U.S. Gov't Germany 2011/08/09 Anal Bioanal Chem. 2011 Oct; 401(6):1889-98. doi: 10.1007/s00216-011-5259-x. Epub 2011 Aug 6" |
