Publications

2016

Anna Szabo, Karl Unterkofler, Pawel Mochalski, Martin Jandacka, Veronika Ruzsanyi, G Szabó, Á Mohácsi, Susanne Teschl, Gerald Teschl, and Julian King. Modeling of breath methane concentration profiles during exercise on an ergometer. J Breath Res, 10(1):17105, 2016. [ DOI | http ]

We develop a simple three compartment model based on mass balance equations which quantitatively describes the dynamics of breath methane concentration profiles during exercise on an ergometer. With the help of this model it is possible to estimate the endogenous production rate of methane in the large intestine by measuring breath gas concentrations of methane.

 


Wojciech Filipiak, Pawel Mochalski, Jakob Troppmair, Karl Unterkofler, Agapios Agapiou, Cristina E Davis, Raquel Cumeras, Clemens Ager, and Anna Filipiak. A compendium of volatile organic compounds (VOCs) released by human cell lines. Current Medicinal Chemistry, 23(999):1--1, 2016. [ DOI | http ]

Volatile organic compounds (VOCs) offer unique insights into ongoing biochemical processes in healthy and diseased humans. Yet, their diagnostic use is hampered by the limited understanding of their biochemical or cellular origin and their frequently unclear link to the underlying diseases. Major advancements are expected from the analyses of human primary cells, cell lines and cultures of microorganisms. In this review, a database of 125 reliably identified VOCs previously reported for human healthy and diseased cells was assembled and their potential origin is discussed. The majority of them have also been observed in studies with other human matrices (breath, urine, saliva, feces, blood, skin emanations). Moreover, continuing improvements of qualitative and quantitative analyses, based on the recommendations of the ISO-11843 guidelines, are suggested for the necessary standardization of analytical procedures and better comparability of results. The data provided contribute to arriving at a more complete human volatilome and suggest potential volatile biomarkers for future validation. Dedication:This review is dedicated to the memory of Prof. Dr. Anton Amann, who sadly passed away on January 6, 2015. He was motivator and motor for the field of breath research.

 


Pawel Mochalski and Karl Unterkofler. Quantification of selected volatile organic compounds in human urine by gas chromatography selective reagent ionization time of flight mass spectrometry (GC-SRI-TOF-MS) coupled with head-space solid-phase microextraction (HS-SPME). The Analyst, 141(15):4796--4803, 2016. [ DOI | http ]

Selective reagent ionization time of flight mass spectrometry with NO(+) as the reagent ion (SRI-TOF-MS(NO(+))) in conjunction with gas chromatography (GC) and head-space solid-phase microextraction (HS-SPME) was used to determine selected volatile organic compounds in human urine. A total of 16 volatiles exhibiting high incidence rates were quantified in the urine of 19 healthy volunteers. Amongst them there were ten ketones (acetone, 2-butanone, 3-methyl-2-butanone, 2-pentanone, 3-methyl-2-pentanone, 4-methyl-2-pentanone, 2-hexanone, 3-hexanone, 2-heptanone, and 4-heptanone), three volatile sulphur compounds (dimethyl sulfide, allyl methyl sulfide, and methyl propyl sulfide), and three heterocyclic compounds (furan, 2-methylfuran, 3-methylfuran). The concentrations of the species under study varied between 0.55 nmol L(-1) (0.05 nmol mmol(-1)creatinine) for allyl methyl sulfide and 11.6 mumol L(-1) (1.54 mumol mmol(-1)creatinine) for acetone considering medians. Limits of detection (LODs) ranged from 0.08 nmol L(-1) for allyl methyl sulfide to 1.0 nmol L(-1) for acetone and furan (with RSDs ranging from 5 to 9%). The presented experimental setup assists both real-time and GC analyses of volatile organic compounds, which can be performed consecutively using the same analytical system. Such an approach supports the novel concept of hybrid volatolomics, an approach which combines VOC profiles obtained from two or more body fluids to improve and complement the chemical information on the physiological status of an individual.

 


R Fernández del Río, M E O'Hara, P Pemberton, T Whitehouse, Chris A. Mayhew, and M E O'Hara. Elimination characteristics of post-operative isoflurane levels in alveolar exhaled breath via PTR-MS analysis. J Breath Res, 10(4):46006, 2016. [ DOI | http ]

Isoflurane (1-chloro-2,2,2-trifluoroethyl difluoromethyl ether), C3H2ClF5O, is a commonly used inhalation anaesthetic. Using a proton transfer reaction mass spectrometer (PTR-MS) we have detected isoflurane in the breath of patients several weeks following major surgery. That isoflurane is detected in the breath of patients so long after being anaesthetised raises questions about when cognitive function has fully returned to a patient. Temporal profiles of isoflurane concentrations in breath are presented for five patients (F/M 3/2, mean age 50 years, min-max 36-58 years) who had undergone liver transplant surgery. In addition, results from a headspace analysis of isoflurane are presented so that the product ions resulting from the reactions of H3O+ with isoflurane in PTR-MS could be easily identified in the absence of the complex chemical environment of breath. Six product ions were identified. In order of increasing m/z (using the 35Cl isotope where appropriate) these are [Formula: see text] (m/z 51), CHFCl+ (m/z 67), CF3CHCl+ (m/z 117), C3F4OCl+ (m/z 163), C3H2F4OCl+ (m/z 165), and C3F4OCl+ H2O (m/z 183). No protonated parent was detected. For the headspace study both clean air and CO2 enriched clean air (4% CO2) were used as buffer gases in the drift tube of the PTR-MS. The CO2 enriched air was used to determine if exhaled breath would affect the product ion branching ratios. Importantly no significant differences were observed, and therefore for isoflurane the product ion distributions determined in a normal air mixture can be used for breath analysis. Given that PTR-MS can be operated under different reduced electric fields (E/N), the dependence of the product ion branching percentages for isoflurane on E/N (96-138 Td) are reported.

 


Christian Kramer, Pawel Mochalski, Karl Unterkofler, Agapios Agapiou, Veronika Ruzsanyi, and Klaus R Liedl. Prediction of blood:air and fat:air partition coefficients of volatile organic compounds for the interpretation of data in breath gas analysis. Journal of Breath Research, 10(1):017103, 2016. [ DOI | http ]

2016 IOP Publishing Ltd. In this article, a database of blood:air and fat:air partition coefficients (λ b:a and λ f:a) is reported for estimating 1678 volatile organic compounds recently reported to appear in the volatilome of the healthy human. For this purpose, a quantitative structure-property relationship (QSPR) approach was applied and a novel method for Henry's law constants prediction developed. A random forest model based on Molecular Operating Environment 2D (MOE2D) descriptors based on 2619 literature-reported Henry's constant values was built. The calculated Henry's law constants correlate very well (R 2 test = 0.967) with the available experimental data. Blood:air and fat:air partition coefficients were calculated according to the method proposed by Poulin and Krishnan using the estimated Henry's constant values. The obtained values correlate reasonably well with the experimentally determined ones for a test set of 90 VOCs (R 2 = 0.95). The provided data aim to fill in the literature data gap and further assist the interpretation of results in studies of the human volatilome.

 


Veronika Ruzsanyi, P Heinz-Erian, Andreas Entenmann, D Karall, T Muller, Alexander Schimkowitsch, Anton Amann, and Sabine Scholl-Bürgi. Diagnosing lactose malabsorption in children: difficulties in interpreting hydrogen breath test results. J Breath Res, 10(1):16015, 2016. [ DOI | http ]

Lactose malabsorption (LM) is caused by insufficient enzymatic degradation of the disaccharide by intestinal lactase. Although hydrogen (H2) breath tests (HBTs) are routinely applied to diagnose LM, false-negative results are not uncommon. Thirty-two pediatric patients (19 females, 13 males) were included in this prospective study. After oral lactose administration (1 g kg(-1) bodyweight to a maximum of 25 g), breath H2 was measured by electrochemical detection. HBT was considered positive if H2 concentration exceeded an increase of 20 ppm from baseline. In addition to H2, exhaled methane (CH4), blood glucose concentrations and clinical symptoms (flatulence, abdominal pain, diarrhea) were monitored. A positive HBT indicating LM was found in 12/32 (37.5%) patients. Only five (41.7%, 5/12) of these had clinical symptoms during HBT indicating lactose intolerance (LI). Decreased blood glucose concentration increments (20 mg dL(-1) (1.1 mmol L(-1))) were found in 3/5 of these patients. CH4 concentrations 10 ppm at any time during the test were observed in 5/32 (15.6%) patients and in 9/32 (28.1%) between 1 ppm and 9 ppm above baseline after lactose ingestion. In patients with positive HBT 10/12 (83.3%) showed elevated CH4 (1 ppm) above baseline in breath gas, whereas in patients with negative HBT this figure was only 4/17 (23.5%). In addition to determining H2 in exhaled air, documentation of clinical symptoms, measurement of blood glucose and breath CH4 concentrations may be helpful in deciding whether in a given case an HBT correctly identifies patients with clinically relevant LM.

 


Veronika Ruzsanyi, Peter Heinz-Erian, Andreas Entenmann, Daniela Karall, Thomas Müller, Alexander Schimkowitsch, Anton Amann, and Sabine Scholl-Bürgi. Diagnosing lactose malabsorption in children: difficulties in interpreting hydrogen breath test results. Journal of breath research, 10(1):016015, 2016. [ DOI | http ]

Lactose malabsorption (LM) is caused by insufficient enzymatic degradation of the disaccharide by intestinal lactase. Although hydrogen (H2) breath tests (HBTs) are routinely applied to diagnose LM, false-negative results are not uncommon. Thirty-two pediatric patients (19 females, 13 males) were included in this prospective study. After oral lactose administration (1 g kg(-1) bodyweight to a maximum of 25 g), breath H2 was measured by electrochemical detection. HBT was considered positive if H2 concentration exceeded an increase of  ⩾20 ppm from baseline. In addition to H2, exhaled methane (CH4), blood glucose concentrations and clinical symptoms (flatulence, abdominal pain, diarrhea) were monitored. A positive HBT indicating LM was found in 12/32 (37.5%) patients. Only five (41.7%, 5/12) of these had clinical symptoms during HBT indicating lactose intolerance (LI). Decreased blood glucose concentration increments (⩽20 mg dL(-1) (⩽1.1 mmol L(-1))) were found in 3/5 of these patients. CH4 concentrations  ⩾10 ppm at any time during the test were observed in 5/32 (15.6%) patients and in 9/32 (28.1%) between 1 ppm and 9 ppm above baseline after lactose ingestion. In patients with positive HBT 10/12 (83.3%) showed elevated CH4 (1 ppm) above baseline in breath gas, whereas in patients with negative HBT this figure was only 4/17 (23.5%). In addition to determining H2 in exhaled air, documentation of clinical symptoms, measurement of blood glucose and breath CH4 concentrations may be helpful in deciding whether in a given case an HBT correctly identifies patients with clinically relevant LM.

 


2015

Pawel Mochalski, Karl Unterkofler, Patrik Španěl, David M Smith, and Anton Amann. Product ion distributions for the reactions of NO+ with some N-containing and O-containing heterocyclic compounds obtained using SRI-TOF-MS. International Journal of Mass Spectrometry, 386:42--46, 2015. [ DOI ]

Product ion distributions for the reactions of NOsup+/sup with nine O-containing and six N-containing heterocyclic compounds present in human volatilome have been determined under the conditions of a Selective Reagent Ionization Time of Flight Mass Spectrometer (SRI-TOF-MS) at E/N values in the drift tube reactor ranging from 90 to 130 Td. This study was undertaken to provide the kinetics data by which these heterocyclic compounds could be analyzed in biogenic media using SRI-TOF-MS. The specific heterocyclic compounds are furan, 2-methylfuran, 3-methylfuran, 2,5-dimethylfuran, 2-pentylfuran, 2,3-dihydrofuran, 1,3-dioxolane, 2-methyl-1,3-dioxolane, γ-butyrolactone, pyrrole, 1-methylpyrrole, pyridine, 2,6-dimethylpyridine, pyrimidine, and 4-methylpyrimidine. Charge transfer was the dominant mechanism in the majority of these NOsup+/sup reactions generating the respective Msup+/sup parent cation, but in the pyridine, pyrimidine, and 4-methylpyrimidine reactions, stable NOsup+/supM adduct ions were the major products with Msup+/sup ions as minor products. The reactions of dioxolanes with NOsup+/sup proceeded by hydride ion transfer only producing (M-H)sup+/sup ions. Fragmentation of the excited nascent product ions (Msup+/sup)sup∗/sup did not occur for the majority of these reactions under the particular chosen conditions of the SRI-TOF-MS reactor, but partial fragmentation did occur in the 2,3-dihydrofuran and 2-pentylfuran reactions. However, lowering of the E/N in the drift tube suppresses fragmentation of (Msup+/sup)sup∗/sup ions and promotes the formation of NOsup+/supM adduct ions, whereas increasing E/N has the opposite effect, as expected. The product ion distributions were seen to be independent of the humidity of the sample gas.

 


Anna Szabo, Veronika Ruzsanyi, Karl Unterkofler, Á Mohácsi, E Tuboly, M Boros, G Szabó, Hartmann Hinterhuber, and Anton Amann. Exhaled methane concentration profiles during exercise on an ergometer. Journal of Breath Research, 9(1):016009, 2015. [ DOI | arXiv | http ]

Exhaled methane concentration measurements are extensively used in medical investigation of certainngastrointestinal conditions. However, the dynamics of endogenous methane release is largely unknown.nBreath methane profiles during ergometer tests were measured by means of a photoacousticnspectroscopy based sensor. Five methane-producing volunteers (with exhaled methane level being atnleast 1 ppm higher than room air) were measured. The experimental protocol consisted of 5 minnrest—15 min pedalling (at a workload of 75 W)—5 min rest. In addition, hemodynamic and respiratorynparameters were determined and compared to the estimated alveolar methane concentration. Thenalveolar breath methane level decreased considerably, by a factor of 3–4 within 1.5 min, while thenestimated ventilation-perfusion ratio increased by a factor of 2–3. Mean pre-exercise and exercisenmethane concentrations were 11.4 ppm (SD:7.3) and 2.8 ppm (SD:1.9), respectively. The changes can bendescribed by the high sensitivity of exhaled methane to ventilation-perfusion ratio and are in linenwith the Farhi equation.

 


Yoav Y. Broza, Pawel Mochalski, Veronika Ruzsanyi, Anton Amann, and Hossam Haick. Hybrid Volatolomics and Disease Detection. Angewandte Chemie - International Edition, 54(38):11036--11048, 2015. [ DOI | http ]

This Review presents a concise, but not exhaustive, didactic overview of some of the main concepts and approaches related to "volatolomics"-an emerging frontier for fast, risk-free, and potentially inexpensive diagnostics. It attempts to review the source and characteristics of volatolomics through the so-called volatile organic compounds (VOCs) emanating from cells and their microenvironment. It also reviews the existence of VOCs in several bodily fluids, including the cellular environment, blood, breath, skin, feces, urine, and saliva. Finally, the usefulness of volatolomics for diagnosis from a single bodily fluid, as well as ways to improve these diagnostic aspects by "hybrid" approaches that combine VOC profiles collected from two or more bodily fluids, will be discussed. The perspectives of this approach in developing the field of diagnostics to a new level are highlighted.

 


Pawel Mochalski, Markus Theurl, Andreas Sponring, Karl Unterkofler, Rudolf Kirchmair, and Anton Amann. Analysis of Volatile Organic Compounds Liberated and Metabolised by Human Umbilical Vein Endothelial Cells (HUVEC) In Vitro. Cell biochemistry and biophysics, 71(1):323--329, aug 2015. [ DOI | http ]

Gas chromatography with mass spectrometric detection combined with head-space needle trap extraction as the pre-concentration technique was applied to identify and quantify volatile organic compounds released or metabolised by human umbilical vein endothelial cells. Amongst the consumed species there were eight aldehydes (2-methyl 2-propenal, 2-methyl propanal, 2-methyl butanal, 3-methyl butanal, n-hexanal, benzaldehyde, n-octanal and n-nonanal) and n-butyl acetate. Further eight compounds (ethyl acetate, ethyl propanoate, ethyl butyrate, 3-heptanone, 2-octanone, 2-nonanone, 2-methyl-5-(methylthio)-furan and toluene) were found to be emitted by the cells under study. Possible metabolic pathways leading to the uptake and release of these compounds by HUVEC are proposed and discussed. The uptake of aldehydes by endothelial cells questions the reliability of species from this chemical class as breath or blood markers of disease processes in human organism. The analysis of volatiles released or emitted by cell lines is shown to have a potential for the identification and assessment of enzymes activities and expression.

 


Agapios Agapiou, Anton Amann, Pawel Mochalski, Milt Statheropoulos, and C. L P Thomas. Trace detection of endogenous human volatile organic compounds for search, rescue and emergency applications. TrAC - Trends in Analytical Chemistry, 66:158--175, 2015. [ DOI | http ]

Since Pauling's paper in the 1970s, interest has increased in volatile organic compounds (VOCs) released from different bio-fluids, such as blood and urine. A number of VOCs reflect internal biochemical pathways occurring in the human body and their chemical pattern may serve as the chemical platform for tracing human VOCs. Monitoring endogenous human VOCs is proposed as an alternative method to the use of canines for search, rescue and emergency applications. Tracing human VOCs requires robust, rapid, reliable and sensitive analytical instruments. Instrumentation currently used to study human VOC biomarkers (e.g. GC-MS, PTR-MS, SIFT-MS, MCC-IMS, FAIMS and sensor based systems) has significant clinical potential, but has yet to receive widespread consideration for emergency search applications.

 


Wojciech Filipiak, Ronny Beer, Andreas Sponring, Anna Filipiak, Clemens Ager, Alois Schiefecker, Simon Lanthaler, Raimund Helbok, Markus Nagl, Jakob Troppmair, and Anton Amann. Breath analysis for in vivo detection of pathogens related to ventilator-associated pneumonia in intensive care patients: a prospective pilot study. Journal of breath research, 9(1):016004, mar 2015. [ DOI | http ]

Existing methods for the early detection of infections in mechanically ventilated (MV) patients at intensive care units (ICUs) are unsatisfactory. Here we present an exploratory study assessing the feasibility of breath VOC analyses for the non-invasive detection of pathogens in the lower respiratory tract of ventilated patients. An open uncontrolled clinical pilot study was performed by enrolling 28 mechanically ventilated (MV) patients with severe intracranial disease, being at risk for the development of or already with confirmed ventilation-associated pneumonia (VAP). The recently developed sampling technique enabled the collection of breath gas with a maximized contribution of alveolar air directly from the respiratory circuit under continuous capnography control, adsorptive preconcentration and final analysis by means of gas chromatography-mass spectrometry (GC-MS).VAP was confirmed in 22/28 preselected patients (78%). The most common microorganisms were Staphylococcus aureus (5/22 VAP patients), Escherichia coli (5/22 VAP patients) and Candida spp. (5/22 VAP patients). 12/32 metabolites released by S. aureus in our previous in vitro studies were also detected in the end-tidal air of VAP patients infected with this pathogen. A similar overlap was seen in Candida albicans infections (8/29 VOCs). Moreover, the concentration profile of selected compounds correlated with the course of the infection.This prospective pilot study provides proof of the concept that the appearance and the concentration profile of pathogen-derived metabolites (elucidated from in vitro experiments) in the breath of ventilated patients during clinically confirmed VAP correlates with the presence of a particular pathogen.

 


M Boros, E Tuboly, A Meszaros, and Anton Amann. The role of methane in mammalian physiology-is it a gasotransmitter? J Breath Res, 9(1):14001, 2015. [ DOI | http ]

Mammalian methanogenesis is widely considered to be an exclusive sign of anaerobic microbial activity in the gastrointestinal tract. This commonly held view was challenged, however, when in vitro and in vivo investigations demonstrated the possibility of nonmicrobial methane formation in aerobic organisms, in plants and animals. The aim of this review is to discuss the available literature data on the biological role of methane. When we evaluate the significance of methane generation in the mammalian physiology, the question may be examined: is it a gas mediator? Overall the data do not fully support the gasotransmitter concept, but they do support the notion that methane liberation may be linked to redox regulation and may be connected with hypoxic events leading to, or associated with a mitochondrial dysfunction. In this respect, the available information suggests that hypoxia-induced methane generation may be a necessary phenomenon of aerobic life, and perhaps a surviving evolutionary trait in the eukaryote cell.

 


Pawel Mochalski, Karl Unterkofler, Gerald Teschl, and Anton Amann. Potential of volatile organic compounds as markers of entrapped humans for use in urban search-and-rescue operations. TrAC Trends in Analytical Chemistry, 68:88--106, 2015. [ DOI | http ]

Volatile organic compounds (VOCs) emitted by a human body form a chemical signature capable of providing invaluable information on the physiological status of an individual and, thereby, serving as signs of life for detecting victims after natural or man-made disasters. For this review, we created a database of potential biomarkers of human presence based on literature reports on VOCs in human breath, skin emanations, blood and urine. We estimated approximate fluxes of these VOCs from the human body, and used them to predict concentrations in the vicinity of victims. We classified proposed markers in groups by potential for victim detection. The major classification discriminants were the capability of detection by portable, real-time analytical instruments and background levels of VOCs in the urban environment. We intend data summarized in this review to assist studies on the detection of humans via chemical analysis and to accelerate investigations in this area of knowledge.

 


Bogdan Calenic, Daniela Miricescu, Maria Greabu, Andrey V Kuznetsov, Jakob Troppmair, Veronika Ruzsanyi, and Anton Amann. Oxidative stress and volatile organic compounds: interplay in pulmonary, cardio-vascular, digestive tract systems and cancer. Open Chemistry, 13(1), 2015. [ DOI ]


Karl Unterkofler, Julian King, Pawel Mochalski, Martin Jandacka, Helin Koc, Susanne Teschl, Anton Amann, and Gerald Teschl. Modeling-based determination of physiological parameters of systemic VOCs by breath gas analysis: a pilot study. Journal of Breath Research, 9(3):036002, may 2015. [ DOI | arXiv | http ]

In this paper we develop a simple two compartment model which extends the Farhi equation to the case when the inhaled concentration of a volatile organic compound (VOC) is not zero. The model connects the exhaled breath concentration of systemic VOCs with physiological parameters such as endogenous production rates and metabolic rates. Its validity is tested with data obtained for isoprene and inhaled deuterated isoprene-D5.

 


Anna Szabo, Veronika Ruzsanyi, Karl Unterkofler, Á Mohácsi, E Tuboly, M Boros, G Szabó, Hartmann Hinterhuber, and Anton Amann. Exhaled methane concentration profiles during exercise on an ergometer. J Breath Res, 9(1):16009, 2015. [ DOI | http ]

Exhaled methane concentration measurements are extensively used in medical investigation of certain gastrointestinal conditions. However, the dynamics of endogenous methane release is largely unknown. Breath methane profiles during ergometer tests were measured by means of a photoacoustic spectroscopy based sensor. Five methane-producing volunteers (with exhaled methane level being at least 1 ppm higher than room air) were measured. The experimental protocol consisted of 5 min rest--15 min pedalling (at a workload of 75 W)--5 min rest. In addition, hemodynamic and respiratory parameters were determined and compared to the estimated alveolar methane concentration. The alveolar breath methane level decreased considerably, by a factor of 3-4 within 1.5 min, while the estimated ventilation-perfusion ratio increased by a factor of 2-3. Mean pre-exercise and exercise methane concentrations were 11.4 ppm (SD:7.3) and 2.8 ppm (SD:1.9), respectively. The changes can be described by the high sensitivity of exhaled methane to ventilation-perfusion ratio and are in line with the Farhi equation.

 


Julia Vamvakari, George C. Pallis, Pawel Mochalski, Felipe Fernandez, Ivo Ramos Maia Martins, Juan Mario Rodríguez, and Milt Statheropoulos. Addressing challenges in using breath chemical analysis in smartphone-based health diagnostics. MOBIHEALTH'15 Proceedings of the 5th EAI International Conference on Wireless Mobile Communication and Healthcare, 2015.


Anna Szabo, Veronika Ruzsanyi, Karl Unterkofler, Á Mohácsi, E Tuboly, M Boros, G Szabó, Hartmann Hinterhuber, and Anton Amann. Exhaled methane concentration profiles during exercise on an ergometer. Journal of Breath Research, 9(1):016009, 2015. [ DOI | arXiv | http ]

Exhaled methane concentration measurements are extensively used in medical investigation of certainngastrointestinal conditions. However, the dynamics of endogenous methane release is largely unknown.nBreath methane profiles during ergometer tests were measured by means of a photoacousticnspectroscopy based sensor. Five methane-producing volunteers (with exhaled methane level being atnleast 1 ppm higher than room air) were measured. The experimental protocol consisted of 5 minnrest—15 min pedalling (at a workload of 75 W)—5 min rest. In addition, hemodynamic and respiratorynparameters were determined and compared to the estimated alveolar methane concentration. Thenalveolar breath methane level decreased considerably, by a factor of 3–4 within 1.5 min, while thenestimated ventilation-perfusion ratio increased by a factor of 2–3. Mean pre-exercise and exercisenmethane concentrations were 11.4 ppm (SD:7.3) and 2.8 ppm (SD:1.9), respectively. The changes can bendescribed by the high sensitivity of exhaled methane to ventilation-perfusion ratio and are in linenwith the Farhi equation.

 


2014

Pawel Mochalski, Julian King, Karl Unterkofler, Hartmann Hinterhuber, and Anton Amann. Emission rates of selected volatile organic compounds from skin of healthy volunteers. J Chromatogr B Analyt Technol Biomed Life Sci, 959:62--70, 2014. [ DOI | http ]

Gas chromatography with mass spectrometric detection (GC-MS) coupled with solid phase micro-extraction as pre-concentration method (SPME) was applied to identify and quantify volatile organic compounds (VOCs) emitted by human skin. A total of 64 C4-C10 compounds were quantified in skin emanation of 31 healthy volunteers. Amongst them aldehydes and hydrocarbons were the predominant chemical families with eighteen and seventeen species, respectively. Apart from these, there were eight ketones, six heterocyclic compounds, six terpenes, four esters, two alcohols, two volatile sulphur compounds, and one nitrile. The observed median emission rates ranged from 0.55 to 4,790 fmol cm(-2)min(-1). Within this set of analytes three volatiles; acetone, 6-methyl-5-hepten-2-one, and acetaldehyde exhibited especially high emission rates exceeding 100 fmol cm(-2)min(-1). Thirty-three volatiles were highly present in skin emanation with incidence rates over 80%. These species can be considered as potential markers of human presence, which could be used for early location of entrapped victims during Urban Search and Rescue Operations (USaR).

 


Anton Amann, Pawel Mochalski, Veronika Ruzsanyi, Yoav Y. Broza, and Hossam Haick. Assessment of the exhalation kinetics of volatile cancer biomarkers based on their physicochemical properties. Journal of breath research, 8(1):016003, 2014. [ DOI | http ]

The current review provides an assessment of the exhalation kinetics of volatile organic compounds (VOCs) that have been linked with cancer. Towards this end, we evaluate various physicochemical properties, such as 'breath:air' and 'blood:fat' partition coefficients, of 112 VOCs that have been suggested over the past decade as potential markers of cancer. With these data, we show that the cancer VOC concentrations in the blood and in the fat span over 12 and 8 orders of magnitude, respectively, in order to provide a specific counterpart concentration in the exhaled breath (e.g., 1 ppb). This finding suggests that these 112 different compounds have different storage compartments in the body and that their exhalation kinetics depends on one or a combination of the following factors: (i) the VOC concentrations in different parts of the body; (ii) the VOC synthesis and metabolism rates; (iii) the partition coefficients between tissue(s), blood and air; and (iv) the VOCs' diffusion constants. Based on this analysis, we discuss how this knowledge allows modeling and simulating the behavior of a specific VOC under different sampling protocols (with and without exertion of effort). We end this review by a brief discussion on the potential role of these scenarios in screening and therapeutic monitoring of cancer.

 


B de Lacy Costello, Anton Amann, H Al-Kateb, C Flynn, Wojciech Filipiak, T Khalid, D Osborne, and Norman Ratcliffe. A review of the volatiles from the healthy human body. Journal of breath research, 8(1), 2014. [ DOI ]

A compendium of all the volatile organic compounds (VOCs) emanating from the human body (the volatolome) is for the first time reported. 1840 VOCs have been assigned from breath (872), saliva (359), blood (154), milk (256), skin secretions (532) urine (279), and faeces (381) in apparently healthy individuals. Compounds were assigned CAS registry numbers and named according to a common convention where possible. The compounds have been grouped into tables according to their chemical class or functionality to permit easy comparison. Some clear differences are observed, for instance, a lack of esters in urine with a high number in faeces. Careful use of the database is needed. The numbers may not be a true reflection of the actual VOCs present from each bodily excretion. The lack of a compound could be due to the techniques used or reflect the intensity of effort e.g. there are few publications on VOCs from blood compared to a large number on VOCs in breath. The large number of volatiles reported from skin is partly due to the methodologies used, e.g. collecting excretions on glass beads and then heating to desorb VOCs. All compounds have been included as reported (unless there was a clear discrepancy between name and chemical structure), but there may be some mistaken assignations arising from the original publications, particularly for isomers. It is the authors' intention that this database will not only be a useful database of VOCs listed in the literature, but will stimulate further study of VOCs from healthy individuals. Establishing a list of volatiles emanating from healthy individuals and increased understanding of VOC metabolic pathways is an important step for differentiating between diseases using VOCs.

 


Anton Amann, Ben De Lacy Costello, Wolfram Miekisch, Jochen K. Schubert, Boguslaw Buszewski, Joachim Pleil, Norman Ratcliffe, Terence Risby, Rosamaria Capuano, Marco Santonico, Giorgio Pennazza, Silvia Ghezzi, Eugenio Martinelli, Claudio Roscioni, Gabriele Lucantoni, Giovanni Galluccio, Roberto Paolesse, Corrado Di Natale, and Arnaldo D'Amico. The human volatilome: volatile organic compounds (VOCs) in exhaled breath, skin emanations, urine, feces and saliva. Journal of breath research, 8(3):034001, 2014. [ DOI | http ]

Breath analysis is a young field of research with its roots in antiquity. Antoine Lavoisier discovered carbon dioxide in exhaled breath during the period 1777-1783, Wilhelm (Vilém) Petters discovered acetone in breath in 1857 and Johannes Müller reported the first quantitative measurements of acetone in 1898. A recent review reported 1765 volatile compounds appearing in exhaled breath, skin emanations, urine, saliva, human breast milk, blood and feces. For a large number of compounds, real-time analysis of exhaled breath or skin emanations has been performed, e.g., during exertion of effort on a stationary bicycle or during sleep. Volatile compounds in exhaled breath, which record historical exposure, are called the 'exposome'. Changes in biogenic volatile organic compound concentrations can be used to mirror metabolic or (patho)physiological processes in the whole body or blood concentrations of drugs (e.g. propofol) in clinical settings-even during artificial ventilation or during surgery. Also compounds released by bacterial strains like Pseudomonas aeruginosa or Streptococcus pneumonia could be very interesting. Methyl methacrylate (CAS 80-62-6), for example, was observed in the headspace of Streptococcus pneumonia in concentrations up to 1420 ppb. Fecal volatiles have been implicated in differentiating certain infectious bowel diseases such as Clostridium difficile, Campylobacter, Salmonella and Cholera. They have also been used to differentiate other non-infectious conditions such as irritable bowel syndrome and inflammatory bowel disease. In addition, alterations in urine volatiles have been used to detect urinary tract infections, bladder, prostate and other cancers. Peroxidation of lipids and other biomolecules by reactive oxygen species produce volatile compounds like ethane and 1-pentane. Noninvasive detection and therapeutic monitoring of oxidative stress would be highly desirable in autoimmunological, neurological, inflammatory diseases and cancer, but also during surgery and in intensive care units. The investigation of cell cultures opens up new possibilities for elucidation of the biochemical background of volatile compounds. In future studies, combined investigations of a particular compound with regard to human matrices such as breath, urine, saliva and cell culture investigations will lead to novel scientific progress in the field.

 


Pawel Mochalski, Karl Unterkofler, Hartmann Hinterhuber, and Anton Amann. Monitoring of selected skin-borne volatile markers of entrapped humans by selective reagent ionization time of flight mass spectrometry in NO+ mode. Anal Chem, 86(8):3915--3923, 2014. [ DOI | .pdf ]

Selective reagent ionization time-of-flight mass spectrometry with NO(+) as the reagent ion (SRI-TOF-MS (NO(+))) was applied for near real-time monitoring of selected skin-borne constituents which are potential markers of human presence. The experimental protocol involved a group of 10 healthy volunteers enclosed in a body plethysmography chamber mimicking the entrapment environment. A total of 12 preselected omnipresent in human scent volatiles were quantitatively monitored. Among them there were six aldehydes (n-propanal, n-hexanal, n-heptanal, n-octanal, n-nonanal, and 2 methyl 2-propenal), four ketones (acetone, 2-butanone, 3-buten-2-one, and 6-methyl-5-hepten-2-one), one hydrocarbon (2-methyl 2-pentene), and one terpene (DL-limonene). The observed median emission rates ranged from 0.28 to 44.8 nmol x person(-1) x min(-1) (16-1530 fmol x cm(-2) x min(-1)). Within the compounds under study, ketones in general and acetone in particular exhibited the highest abundances. The findings of this study provide invaluable information about formation and evolution of a human-specific chemical fingerprint, which could be used for the early location of entrapped victims during urban search and rescue operations (USaR).

 


Pawel Mochalski, Julian King, M Haas, Karl Unterkofler, Anton Amann, and G Mayer. Blood and breath profiles of volatile organic compounds in patients with end-stage renal disease. BMC Nephrol, 15(1):43, 2014. [ DOI | .pdf ]

BACKGROUND: Monitoring of volatile organic compounds (VOCs) in exhaled breath shows great potential as a non-invasive method for assessing hemodialysis efficiency. In this work we aim at identifying and quantifying of a wide range of VOCs characterizing uremic breath and blood, with a particular focus on species responding to the dialysis treatment. METHODS: Gas chromatography with mass spectrometric detection coupled with solid-phase microextraction as pre-concentration method. RESULTS: A total of 60 VOCs were reliably identified and quantified in blood and breath of CKD patients. Excluding contaminants, six compounds (isoprene, dimethyl sulfide, methyl propyl sulfide, allyl methyl sulfide, thiophene and benzene) changed their blood and breath levels during the hemodialysis treatment. CONCLUSIONS: Uremic breath and blood patterns were found to be notably affected by the contaminants from the extracorporeal circuits and hospital room air. Consequently, patient exposure to a wide spectrum of volatile species (hydrocarbons, aldehydes, ketones, aromatics, heterocyclic compounds) is expected during hemodialysis. Whereas highly volatile pollutants were relatively quickly removed from blood by exhalation, more soluble ones were retained and contributed to the uremic syndrome. At least two of the species observed (cyclohexanone and 2-propenal) are uremic toxins. Perhaps other volatile substances reported within this study may be toxic and have negative impact on human body functions. Further studies are required to investigate if VOCs responding to HD treatment could be used as markers for monitoring hemodialysis efficiency.

 


Karl Unterkofler, Julian King, and Pawel Mochalski. Determination of physiological parameters by breath gas analysis. arXiv preprint arXiv: ..., (October 2014):1--13, 2014. [ arXiv | http ]


Hossam Haick, Yoav Y. Broza, Pawel Mochalski, Veronika Ruzsanyi, and Anton Amann. Assessment, origin, and implementation of breath volatile cancer markers. Chemical Society reviews, 43(5):1423--49, mar 2014. [ DOI | http ]

A new non-invasive and potentially inexpensive frontier in the diagnosis of cancer relies on the detection of volatile organic compounds (VOCs) in exhaled breath samples. Breath can be sampled and analyzed in real-time, leading to fascinating and cost-effective clinical diagnostic procedures. Nevertheless, breath analysis is a very young field of research and faces challenges, mainly because the biochemical mechanisms behind the cancer-related VOCs are largely unknown. In this review, we present a list of 115 validated cancer-related VOCs published in the literature during the past decade, and classify them with respect to their "fat-to-blood" and "blood-to-air" partition coefficients. These partition coefficients provide an estimation of the relative concentrations of VOCs in alveolar breath, in blood and in the fat compartments of the human body. Additionally, we try to clarify controversial issues concerning possible experimental malpractice in the field, and propose ways to translate the basic science results as well as the mechanistic understanding to tools (sensors) that could serve as point-of-care diagnostics of cancer. We end this review with a conclusion and a future perspective.

 


Anton Amann, Wolfram Miekisch, Jochen K. Schubert, Boguslaw Buszewski, Tomasz Ligor, Tadeusz Jezierski, Joachim Pleil, and Terence Risby. Analysis of exhaled breath for disease detection. Annual review of analytical chemistry (Palo Alto, Calif.), 7(1):455--82, 2014. [ DOI | http ]

Breath analysis is a young field of research with great clinical potential. As a result of this interest, researchers have developed new analytical techniques that permit real-time analysis of exhaled breath with breath-to-breath resolution in addition to the conventional central laboratory methods using gas chromatography-mass spectrometry. Breath tests are based on endogenously produced volatiles, metabolites of ingested precursors, metabolites produced by bacteria in the gut or the airways, or volatiles appearing after environmental exposure. The composition of exhaled breath may contain valuable information for patients presenting with asthma, renal and liver diseases, lung cancer, chronic obstructive pulmonary disease, inflammatory lung disease, or metabolic disorders. In addition, oxidative stress status may be monitored via volatile products of lipid peroxidation. Measurement of enzyme activity provides phenotypic information important in personalized medicine, whereas breath measurements provide insight into perturbations of the human exposome and can be interpreted as preclinical signals of adverse outcome pathways.

 


2013

Pawel Mochalski, Julian King, Martin Klieber, Karl Unterkofler, Hartmann Hinterhuber, Matthias Baumann, and Anton Amann. Blood and breath levels of selected volatile organic compounds in healthy volunteers. The Analyst, 138(7):2134--45, 2013. [ DOI | http ]

Gas chromatography with mass spectrometric detection (GC-MS) was used to identify and quantify volatile organic compounds in the blood and breath of healthy individuals. Blood and breath volatiles were pre-concentrated using headspace solid phase micro-extraction (HS-SPME) and needle trap devices (NTDs), respectively. The study involved a group of 28 healthy test subjects and resulted in the quantification of a total of 74 compounds in both types of samples. The concentrations of the species under study varied between 0.01 and 6700 nmol L(-1) in blood and between 0.02 and 2500 ppb in exhaled air. Limits of detection (LOD) ranged from 0.01 to 270 nmol L(-1) for blood compounds and from 0.01 to 0.7 ppb for breath species. Relative standard deviations for both measurement regimes varied from 1.5 to 14%. The predominant chemical classes among the compounds quantified were hydrocarbons (24), ketones (10), terpenes (8), heterocyclic compounds (7) and aromatic compounds (7). Twelve analytes were found to be highly present in both blood and exhaled air (with incidence rates higher than 80%) and for 32 species significant differences (Wilcoxon signed-rank test) between room air and exhaled breath were observed. By comparing blood, room air and breath levels in parallel, a tentative classification of volatiles into endogenous and exogenous compounds can be achieved.

 


Pawel Mochalski, Julian King, Karl Unterkofler, and Anton Amann. Stability of selected volatile breath constituents in Tedlar, Kynar and Flexfilm sampling bags. Analyst, 138(5):1405--1418, 2013. [ DOI | http ]

The stability of 41 selected breath constituents in three types of polymer sampling bags, Tedlar, Kynar, and Flexfilm, was investigated using solid phase microextraction and gas chromatography mass spectrometry. The tested molecular species belong to different chemical classes (hydrocarbons, ketones, aldehydes, aromatics, sulphurs, esters, terpenes, etc.) and exhibit close-to-breath low ppb levels (3-12 ppb) with the exception of isoprene, acetone and acetonitrile (106 ppb, 760 ppb, 42 ppb respectively). Stability tests comprised the background emission of contaminants, recovery from dry samples, recovery from humid samples (RH 80% at 37 degrees C), influence of the bag's filling degree, and reusability. Findings yield evidence of the superiority of Tedlar bags over remaining polymers in terms of background emission, species stability (up to 7 days for dry samples), and reusability. Recoveries of species under study suffered from the presence of high amounts of water (losses up to 10%). However, only heavier volatiles, with molecular masses higher than 90, exhibited more pronounced losses (20-40%). The sample size (the degree of bag filling) was found to be one of the most important factors affecting the sample integrity. To sum up, it is recommended to store breath samples in pre-conditioned Tedlar bags up to 6 hours at the maximum possible filling volume. Among the remaining films, Kynar can be considered as an alternative to Tedlar; however, higher losses of compounds should be expected even within the first hours of storage. Due to the high background emission Flexfilm is not suitable for sampling and storage of samples for analyses aiming at volatiles at a low ppb level.

 


Agapios Agapiou, Pawel Mochalski, Alex Schmid, and Anton Amann. Potential Applications of Volatile Organic Compounds in Safety and Security. In SmithD. Amann A., editor, Volatile Biomarkers, chapter 24, pages 514--558. Elsevier, India, 1st edition, 2013. [ DOI | http ]


Bogdan Calenic, Wojciech Filipiak, Maria Greabu, and Anton Amann. Volatile Organic Compounds Expression in Different Cell Types: An In Vitro Approach. phaps.com, (8):43--51, 2013. [ http ]


Veronika Ruzsanyi, Lukas Fischer, Jens Herbig, Clemens Ager, and Anton Amann. Multi-capillary-column proton-transfer-reaction time-of-flight mass spectrometry. Journal of Chromatography A, 1316:112--118, sep 2013. [ DOI | http ]

Proton-transfer-reaction time-of-flight mass-spectrometry (PTR-TOFMS) exhibits high selectivity with a resolution of around 5000m/Δm. While isobars can be separated with this resolution, discrimination of isomeric compounds is usually not possible. The coupling of a multi-capillary column (MCC) with a PTR-TOFMS overcomes these problems as demonstrated in this paper for the ketone isomers 3-heptanone and 2-methyl-3-hexanone and for different aldehydes. Moreover, fragmentation of compounds can be studied in detail which might even improve the identification. LODs for compounds tested are in the range of low ppbv and peak positions of the respective separated substances show good repeatability (RSD of the peak positions 3.2%). Due to its special characteristics, such as isothermal operation, compact size, the MCC setup is suitable to be installed inside the instrument and the overall retention time for a complete spectrum is only a few minutes: this allows near real-time measurements in the optional MCC mode. In contrast to other methods that yield additional separation, such as the use of pre-cursor ions other than H3O(+), this method yields additional information without increasing complexity.

 


Wojciech Filipiak, Anna Filipiak, Andreas Sponring, Thomas Schmid, Bettina Zelger, Clemens Ager, Ewa Klodzinska, Hubert Denz, Alex Pizzini, Paolo Lucciarini, Herbert Jamnig, Jakob Troppmair, Anton Amann, Paolo Lucciarini, and Jakob Troppmair. Comparative analyses of volatile organic compounds (VOCs) from patients, tumors and transformed cell lines for the validation of lung cancer-derived breath markers. Cancer Epidemiology, Biomarkers & Prevention, 8(0):22, may 2013. [ DOI | http ]

Breath analysis for the purpose of non-invasive diagnosis of lung cancer has yielded numerous candidate compounds with still questionable clinical relevance. To arrive at suitable volatile organic compounds our approach combined the analysis of different sources: isolated tumor samples compared to healthy lung tissues, and exhaled breath from lung cancer patients and healthy controls. Candidate compounds were further compared to substances previously identified in the comparison of transformed and normal lung epithelial cell lines. For human studies, a breath sampling device was developed enabling automated and CO2-controlled collection of the end-tidal air. All samples were first preconcentrated on multibed sorption tubes and analyzed with gas chromatography mass spectrometry (GC-MS). Significantly (p 0.05) higher concentrations in all three types of cancer samples studied were observed for ethanol and n-octane. Additional metabolites (inter alia 2-methylpentane, n-hexane) significantly released by lung cancer cells were observed at higher levels in cancer lung tissues and breath samples (compared to respective healthy controls) with statistical significance (p 0.05) only in breath samples. The results obtained confirmed the cancer-related origin of volatile metabolites, e.g. ethanol and octane that were both detected at significantly (p 0.05) elevated concentrations in all three kinds of cancer samples studied. This work is an important step towards identification of volatile breath markers of lung cancer through the demonstration of cancer-related origin of certain volatile metabolites.

 


Wojciech Filipiak. Breath Analysis : origin and application of volatile biomarkers for non-invasive diagnosis of lung diseases. Phd thesis, Innsbruck, 2013.


M Righettoni, Alex Schmid, Anton Amann, and S E Pratsinis. Correlations between blood glucose and breath components from portable gas sensors and PTR-TOF-MS. J Breath Res, 7(3):37110, 2013. [ DOI | http ]

Acetone is one of the most abundant volatile compounds in the human breath and might be important for monitoring diabetic patients. Here, a portable acetone sensor consisting of flame-made, nanostructured, Si-doped WO3 sensing films was used to analyse the end tidal fraction of the breath (collected in Tedlar bags) from eight healthy volunteers after overnight fasting (morning) and after lunch (afternoon). After breath sampling, the gaseous components were also analysed by proton transfer reaction time-of-flight mass spectrometry (PTR-TOF-MS), and each person's blood glucose level was measured. The portable sensor accurately detected the presence of acetone with fast response/recovery times (12 s) and a high signal-to-noise ratio. Statistical analysis of the relationship between the PTR-TOF-MS measurements of breath gases (e.g., acetone, isoprene, ethanol and methanol), sensor response and the blood glucose level was performed for both sampling periods. The best correlations were found after overnight fasting (morning): in particular, between blood glucose level and breath acetone (Pearson's 0.98 and Spearman's 0.93). Whereas the portable sensor response correlated best with the blood glucose (Pearson's 0.96 and Spearman's 0.81) and breath acetone (Pearson's 0.92 and Spearman's 0.69).

 


Veronika Ruzsanyi. Ion mobility spectrometry for pharmacokinetic studies-exemplary application. Journal of breath research, 7(4), 2013. [ DOI | http ]

Breath analysis is an attractive non-invasive method for diagnosis and therapeutic monitoring. It uses endogenously produced compounds and metabolites of isotopically labeled precursors. In order to make such tests clinically useful, it is important to have relatively small portable instruments detecting volatile compounds within short time. A particularly promising analytical technique is ion mobility spectrometry (IMS) coupled to a multi capillary column (MCC). This paper focuses on demonstrating the suitability of breath analysis for pharmacokinetic applications using MCC-IMS with respect to practicability and reproducibility testing the model substrate eucalyptol. Validation of the MCC-IMS measurements were performed using proton transfer reaction mass spectrometry (PTR-MS) and resulted in an excellent correspondence of the time-dependent concentrations presented by the two different analytical techniques. Moreover, the good accordance in variance of kinetic parameters with repeated measures, and the determined inter-subject differences indicate the eligibility of the analysis method.

 


Pawel Mochalski, Andreas Sponring, Julian King, Karl Unterkofler, Jakob Troppmair, and Anton Amann. Release and uptake of volatile organic compounds by human hepatocellular carcinoma cells (HepG2) in vitro. Cancer Cell Int, 13(1):72, 2013. [ DOI | .pdf ]

BACKGROUND: Volatile organic compounds (VOCs) emitted by human body offer a unique insight into biochemical processes ongoing in healthy and diseased human organisms. Unfortunately, in many cases their origin and metabolic fate have not been yet elucidated in sufficient depth, thus limiting their clinical application. The primary goal of this work was to identify and quantify volatile organic compounds being released or metabolized by HepG2 hepatocellular carcinoma cells. METHODS: The hepatocellular carcinoma cells were incubated in specially designed head-space 1-L glass bottles sealed for 24 hours prior to measurements. Identification and quantification of volatiles released and consumed by cells under study were performed by gas chromatography with mass spectrometric detection (GC-MS) coupled with head-space needle trap device extraction (HS-NTD) as the pre-concentration technique. Most of the compounds were identified both by spectral library match as well as retention time comparison based on standards. RESULTS: A total of nine compounds were found to be metabolised and further twelve released by the cells under study (Wilcoxon signed-rank test, p0.05). The former group comprised 6 aldehydes (2-methyl 2-propenal, 2-methyl propanal, 2-ethylacrolein, 3-methyl butanal, n-hexanal and benzaldehyde), n-propyl propionate, n-butyl acetate, and isoprene. Amongst the released species there were five ketones (2-pentanone, 3-heptanone, 2-heptanone, 3-octanone, 2-nonanone), five volatile sulphur compounds (dimethyl sulfide, ethyl methyl sulfide, 3-methyl thiophene, 2-methyl-1-(methylthio)- propane and 2-methyl-5-(methylthio) furan), n-propyl acetate, and 2-heptene. CONCLUSIONS: The emission and uptake of the aforementioned VOCs may reflect the activity of abundant liver enzymes and support the potential of VOC analysis for the assessment of enzymes function.

 


Wojciech Filipiak, Andreas Sponring, Anna Filipiak, Maria Magdalena Baur, Clemens Ager, Helmut Wiesenhofer, Rosa Margesin, Markus Nagl, Jakob Troppmair, and Anton Amann. Volatile Organic Compounds (VOCs) Released by Pathogenic Microorganisms in vitro: Potential Breath Biomarkers. Volatile Biomarkers: Non-Invasive Diagnosis in Physiology and Medicine, page 463, 2013.


Ibrahim Elsayed, Thomas Ludescher, Julian King, Clemens Ager, Michael Trosin, Uygar Senocak, Peter Brezany, Thomas Feilhauer, and Anton Amann. ABA-Cloud: support for collaborative breath research. Journal of breath research, 7(2):026007, jun 2013. [ DOI | http ]

This paper introduces the advanced breath analysis (ABA) platform, an innovative scientific research platform for the entire breath research domain. Within the ABA project, we are investigating novel data management concepts and semantic web technologies to document breath analysis studies for the long run as well as to enable their full automatic reproducibility. We propose several concept taxonomies (a hierarchical order of terms from a glossary of terms), which can be seen as a first step toward the definition of conceptualized terms commonly used by the international community of breath researchers. They build the basis for the development of an ontology (a concept from computer science used for communication between machines and/or humans and representation and reuse of knowledge) dedicated to breath research.

 


Anton Amann and David M Smith. Volatile Biomarkers: Non-Invasive Diagnosis in Physiology and Medicine. Newnes, 2013. [ http ]

Volatile organic compounds (VOCs) in exhaled breath, sweat or urine carry much information on the state of human health. The role of VOCs in clinical diagnosis and therapeutic monitoring is expected to become increasingly significant due to recent advances in the field. Volatile Biomarkers: Non-Invasive Diagnosis in Physiology and Medicine includes the latest discoveries and applications for VOCs from the world's foremost scientists and clinicians working in this emerging analytic area.- Appeals to a multidisciplinary audience, including scientists, researchers, and clinicians with an interest in breath analysis - Features the latest scientific research and technical breakthroughs in the diagnostic and therapeutic aspects of volatile organic compounds - Includes case presentations documenting applications in multiple areas of human health and safety

 


2012

Julian King, Alexander Kupferthaler, Birgit Frauscher, Heinz Hackner, Karl Unterkofler, Gerald Teschl, Hartmann Hinterhuber, Anton Amann, and Birgit Högl. Measurement of endogenous acetone and isoprene in exhaled breath during sleep. Physiological measurement, 33(3):413--28, mar 2012. [ DOI | .pdf ]

This explorative study aims at characterizing the breath behavior of two prototypic volatile organic compounds, acetone and isoprene, during normal human sleep and to possibly relate changes in the respective concentration time courses to the underlying sleep architecture. For this purpose, six normal healthy volunteers (two females, four males, age 20-29 years) were monitored over two consecutive nights (the first one being an adaption night) by combining real-time proton-transfer-reaction mass spectrometry measurements from end-tidal exhalation segments with laboratory-based polysomnographic data. Breath acetone concentrations increased overnight in all measurements, with an average relative change by a factor of up to 4 (median 2.5). Nighttime concentration maxima were usually recorded 2-3 h before lights on. For breath isoprene, a nocturnal increase in baseline concentrations of about 74% was observed, with individual changes ranging from 36-110%. Isoprene profiles exhibited pronounced concentration peaks, which were highly specific for leg movements as scored by tibial electromyography. Furthermore, relative to a linear trend, baseline isoprene concentrations decreased during the transition from the NREM to the REM phase of a complete sleep cycle.

 


Veronika Ruzsanyi, Pawel Mochalski, Alex Schmid, Helmut Wiesenhofer, Martin Klieber, Hartmann Hinterhuber, and Anton Amann. Ion mobility spectrometry for detection of skin volatiles. Journal of Chromatography B-Analytical Technologies in the Biomedical and Life Sciences, 911:84--92, 2012. [ DOI | http ]

Volatile organic compounds (VOCs) released by humans through their skin were investigated in near real time using ion mobility spectrometry after gas chromatographic separation with a short multi-capillary column. VOCs typically found in a small nitrogen flow covering the skin are 3-methyl-2-butenal, 6-methylhept-5-en-2-one, sec-butyl acetate, benzaldehyde, octanal, 2-ethylhexanol, nonanal and decanal at volume fractions in the low part per billion-(ppb) range. The technique presented here may contribute to elucidating some physiological processes occurring in the human skin. (C) 2012 Elsevier B.V. All rights reserved.

 


Wojciech Filipiak, Andreas Sponring, Maria Magdalena Baur, Clemens AGER, Anna FILIPIAK, Helmut Wiesenhofer, Markus NAGL, Jakob Troppmair, Anton Amann, and Maria Bauer. Characterization of volatile metabolites taken up by or released from Streptococcus pneumoniae and Haemophilus influenzae by using GC-MS. Microbiology, 158(Pt 12):3044--3053, dec 2012. [ DOI | http ]

Volatile organic compounds (VOCs) released from or taken up by Streptococcus pneumoniae and Haemophilus influenzae cultures were analysed by means of GC-MS after adsorption of headspace samples on multi-bed sorption tubes. Sampling was performed at different time points during cultivation of bacteria to follow the dynamics of VOC metabolism. VOCs were identified not only by spectral library match but also based on retention times of native standards. As many as 34 volatile metabolites were released from S. pneumoniae and 28 from H. influenzae, comprising alcohols, aldehydes, esters, hydrocarbons, ketones and sulfur-containing compounds. For both species, acetic acid, acetaldehyde, methyl methacrylate, 2,3-butanedione and methanethiol were found in strongly elevated concentrations and 1-butanol and butanal in moderately elevated concentrations. In addition, characteristic volatile biomarkers were detected for both bacterial species and exclusively for S. pneumoniae, also catabolism of aldehydes (3-methylbutanal and hexanal) was found. The results obtained provide important input into the knowledge about volatile bacterial biomarkers, which may become particularly important for detection of pathogens in upper airways by breath-gas analysis in the future.

 


Wojciech Filipiak, Andreas Sponring, Maria Magdalena Baur, Anna Filipiak, Clemens Ager, Helmut Wiesenhofer, Markus Nagl, Jakob Troppmair, Anton Amann, Maria Bauer, Anna Filipiak, Clemens Ager, Helmut Wiesenhofer, Markus Nagl, Jakob Troppmair, Anton Amann, Maria Magdalena Baur, Anna Filipiak, Clemens Ager, Helmut Wiesenhofer, Markus Nagl, Jakob Troppmair, and Anton Amann. Molecular analysis of volatile metabolites released specifically by Staphylococcus aureus and Pseudomonas aeruginosa. BMC microbiology, 12(1):113, jan 2012. [ DOI | http ]

ABSTRACT: BACKGROUND: The routinely used microbiological diagnosis of ventilator associated pneumonia (VAP) is time consuming and often requires invasive methods for collection of human specimens (e.g. bronchoscopy). Therefore, it is of utmost interest to develop a non-invasive method for the early detection of bacterial infection in ventilated patients, preferably allowing the identification of the specific pathogens. The present work is an attempt to identify pathogen-derived volatile biomarkers in breath that can be used for early and non-invasive diagnosis of ventilator associated pneumonia (VAP). For this purpose, in vitro experiments with bacteria most frequently found in VAP patients, i.e. Staphylococcus aureus and Pseudomonas aeruginosa, were performed to investigate the release or consumption of volatile organic compounds (VOCs). RESULTS: Headspace samples were collected and preconcentrated on multibed sorption tubes at different time points and subsequently analyzed with gas chromatography mass spectrometry (GC-MS). As many as 32 and 37 volatile metabolites were released by S. aureus and P. aeruginosa, respectively. Distinct differences in the bacteria-specific VOC profiles were found, especially with regard to aldehydes (e.g. acetaldehyde, 3-methylbutanal), which were taken up only by P. aeruginosa but released by S. aureus. Differences in concentration profiles were also found for acids (e.g. isovaleric acid), ketones (e.g. acetoin, 2-nonanone), hydrocarbons (e.g. 2-butene, 1,10-undecadiene), alcohols (e.g. 2-methyl-1-propanol, 2-butanol), esters (e.g. ethyl formate, methyl 2-methylbutyrate), volatile sulfur compounds (VSCs, e.g. dimethylsulfide) and volatile nitrogen compounds (VNCs, e.g. 3-methylpyrrole). Importantly, a significant VOC release was found already 1.5 hours after culture start, corresponding to cell numbers of ˜8*106 [CFUs/ml]. CONCLUSIONS: The results obtained provide strong evidence that the detection and perhaps even identification of bacteria could be achieved by determination of characteristic volatile metabolites, supporting the clinical use of breath-gas analysis as non-invasive method for early detection of bacterial lung infections.

 


Pawel Mochalski, Julian King, Alexander Kupferthaler, Karl Unterkofler, Hartmann Hinterhuber, and Anton Amann. Human Blood and Plasma Partition Coefficients for C4-C8 n-alkanes, Isoalkanes, and 1-alkenes. International Journal of Toxicology, 31(3):267--275, 2012. [ DOI | .pdf ]

Human blood:air and plasma:air partition coefficients for C(4)-C(8) n-alkanes, isoalkanes, and 1-alkenes were determined using multiple headspace extraction coupled with solid phase microextraction and gas chromatography. Mean blood:air partition coefficients expressed in the form of dimensionless blood-to-air concentration ratio (g/mL(b)/g/mL(a)) were 0.183, 0.416, 1.08, 2.71, and 5.77 for C(4)-C(8) n-alkanes; 0.079, 0.184, 0.473, 1.3, and 3.18 for C(4)-C(8) isoalkanes; and 0.304, 0.589, 1.32, 3.5, and 7.01 for C(4)-C(8) 1-alkenes, respectively (n = 8). The reported partition coefficient values increased exponentially with boiling points, molecular weights, and the carbon atoms in the particle. The solubility of 1-alkenes in blood was higher than in plasma, whereas the blood:air and plasma:air partition coefficients of n-alkanes and isoalkanes did not differ significantly. Consequently, additional interactions of 1-alkenes with whole blood seem to occur. The presented findings are expected to be particularly useful for assessing the uptake, distribution, and elimination of hydrocarbons in human organism.

 


Meggie Hakim, Yoav Y. Broza, Orna Barash, Nir Peled, Michael Phillips, Anton Amann, and Hossam Haick. Volatile Organic Compounds of Lung Cancer and Possible Biochemical Pathways. Chemical ..., 112(11):5949--66, nov 2012. [ DOI | http ]


Julian King, Pawel Mochalski, Karl Unterkofler, Gerald Teschl, Martin Klieber, M. Stein, Anton Amann, and Matthias Baumann. Breath isoprene: Muscle dystrophy patients support the concept of a pool of isoprene in the periphery of the human body. Biochemical and Biophysical Research Communications, 423(3):526--530, 2012. [ DOI | http ]

Breath isoprene accounts for most of the hydrocarbon removal via exhalation and is thought to serve as a non-invasive indicator for assaying several metabolic effects in the human body. The primary objective of this paper is to introduce a novel working hypothesis with respect to the endogenous source of this compound in humans: the idea that muscle tissue acts as an extrahepatic production site of substantial amounts of isoprene. This new perspective has its roots in quantitative modeling studies of breath isoprene dynamics under exercise conditions and is further investigated here by presenting pilot data from a small cohort of late stage Duchenne muscle dystrophy patients (median age 21, 4 male, 1 female). For these prototypic test subjects isoprene concentrations in end-tidal breath and peripheral venous blood range between 0.09-0.47 and 0.11-0.72. nmol/l, respectively, amounting to a reduction by a factor of 8 and more as compared to established nominal levels in normal healthy adults. While it remains unclear whether isoprene can be ascribed a direct physiological mechanism of action, some indications are given as to why isoprene production might have evolved in muscle. 2012 Elsevier Inc.

 


Wojciech Filipiak, Veronika Ruzsanyi, Pawel Mochalski, Anna Filipiak, Amel Bajtarevic, Clemens Ager, Hubert Denz, Wolfgang Hilbe, Herbert Jamnig, Martin Hackl, Alexander Dzien, Anton Amann, Others, Alexander Dzien, Anton Amann, Others, Alexander Dzien, and Anton Amann. Dependence of exhaled breath composition on exogenous factors, smoking habits and exposure to air pollutants. Journal of breath research, 6(3):036008, aug 2012. [ DOI | http ]

Non-invasive disease monitoring on the basis of volatile breath markers is a very attractive but challenging task. Several hundreds of compounds have been detected in exhaled air using modern analytical techniques (e.g. proton-transfer reaction mass spectrometry, gas chromatography-mass spectrometry) and have even been linked to various diseases. However, the biochemical background for most of compounds detected in breath samples has not been elucidated; therefore, the obtained results should be interpreted with care to avoid false correlations. The major aim of this study was to assess the effects of smoking on the composition of exhaled breath. Additionally, the potential origin of breath volatile organic compounds (VOCs) is discussed focusing on diet, environmental exposure and biological pathways based on other's studies. Profiles of VOCs detected in exhaled breath and inspired air samples of 115 subjects with addition of urine headspace derived from 50 volunteers are presented. Samples were analyzed with GC-MS after preconcentration on multibed sorption tubes in case of breath samples and solid phase micro-extraction (SPME) in the case of urine samples. Altogether 266 compounds were found in exhaled breath of at least 10% of the volunteers. From these, 162 compounds were identified by spectral library match and retention time (based on reference standards). It is shown that the composition of exhaled breath is considerably influenced by exposure to pollution and indoor-air contaminants and particularly by smoking. More than 80 organic compounds were found to be significantly related to smoking, the largest group comprising unsaturated hydrocarbons (29 dienes, 27 alkenes and 3 alkynes). On the basis of the presented results, we suggest that for the future understanding of breath data it will be necessary to carefully investigate the potential biological origin of volatiles, e.g., by means of analysis of tissues, isolated cell lines or other body fluids. In particular, VOCs linked to smoking habit or being the results of human exposure should be considered with care for clinical diagnosis since small changes in their concentration profiles (typically in the ppt(v)-ppb(v) range) revealing that the outbreak of certain disease might be hampered by already high background.

 


Wojciech Filipiak, Anna Filipiak, Clemens Ager, Helmut Wiesenhofer, and Anton Amann. Optimization of sampling parameters for collection and preconcentration of alveolar air by needle traps. Journal of breath research, 6(2):027107, jun 2012. [ DOI | http ]

The approach for breath-VOCs' collection and preconcentration by applying needle traps was developed and optimized. The alveolar air was collected from only a few exhalations under visual control of expired CO(2) into a large gas-tight glass syringe and then warmed up to 45 °C for a short time to avoid condensation. Subsequently, a specially constructed sampling device equipped with Bronkhorst electronic flow controllers was used for automated adsorption. This sampling device allows time-saving collection of expired/inspired air in parallel onto three different needle traps as well as improvement of sensitivity and reproducibility of NT-GC-MS analysis by collection of relatively large (up to 150 ml) volume of exhaled breath. It was shown that the collection of alveolar air derived from only a few exhalations into a large syringe followed by automated adsorption on needle traps yields better results than manual sorption by up/down cycles with a 1 ml syringe, mostly due to avoided condensation and electronically controlled stable sample flow rate. The optimal profile and composition of needle traps consists of 2 cm Carbopack X and 1 cm Carboxen 1000, allowing highly efficient VOCs' enrichment, while injection by a fast expansive flow technique requires no modifications in instrumentation and fully automated GC-MS analysis can be performed with a commercially available autosampler. This optimized analytical procedure considerably facilitates the collection and enrichment of alveolar air, and is therefore suitable for application at the bedside of critically ill patients in an intensive care unit. Due to its simplicity it can replace the time-consuming sampling of sufficient breath volume by numerous up/down cycles with a 1 ml syringe.

 


M Righettoni, A Tricoli, S Gass, Alex Schmid, Anton Amann, and S E Pratsinis. Breath acetone monitoring by portable Si:WO3 gas sensors. Anal Chim Acta, 738:69--75, 2012. [ DOI | http ]

Breath analysis has the potential for early stage detection and monitoring of illnesses to drastically reduce the corresponding medical diagnostic costs and improve the quality of life of patients suffering from chronic illnesses. In particular, the detection of acetone in the human breath is promising for non-invasive diagnosis and painless monitoring of diabetes (no finger pricking). Here, a portable acetone sensor consisting of flame-deposited and in situ annealed, Si-doped epsilon-WO(3) nanostructured films was developed. The chamber volume was miniaturized while reaction-limited and transport-limited gas flow rates were identified and sensing temperatures were optimized resulting in a low detection limit of acetone ( approximately 20ppb) with short response (10-15s) and recovery times (35-70s). Furthermore, the sensor signal (response) was robust against variations of the exhaled breath flow rate facilitating application of these sensors at realistic relative humidities (80-90%) as in the human breath. The acetone content in the breath of test persons was monitored continuously and compared to that of state-of-the-art proton transfer reaction mass spectrometry (PTR-MS). Such portable devices can accurately track breath acetone concentration to become an alternative to more elaborate breath analysis techniques.

 


Pawel Mochalski, Karin Krapf, Clemens Ager, Helmut Wiesenhofer, Agapios Agapiou, Milt Statheropoulos, Dietmar Fuchs, Ernst Ellmerer, Boguslaw Buszewski, and Anton Amann. Temporal profiling of human urine VOCs and its potential role under the ruins of collapsed buildings. Toxicology mechanisms and methods, 22(7):502--11, sep 2012. [ DOI | http ]

Context: The scent profile of human urine was investigated as potential source of chemical markers of human presence in collapsed buildings after natural or man-made disasters. Objective: The main goals of this study were to build a library of potential biomarkers of human urine to be used for the detection of entrapped victims and to further examine their evolution profile in time. Materials and methods: Headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) was used to detect and identify the volatile organic compounds (VOCs) spontaneously released from urine of 20 healthy volunteers. Additionally, the evolution of human urine headspace during four days storage at room temperature was investigated. Results: 33 omnipresent species with incidence higher than 80% were selected as potential urine markers. The most represented chemical classes were ketones with 10 representatives, aldehydes (7 species) and sulfur compounds (7 species). The monitoring of the evolution of the urine scent demonstrated an increase in the emission of 26 omnipresent urinary volatiles (rise from 36% to 526%). The highest increase was noted for dimethyldisulfide and dimethyltrisulfide (fivefold increase) and 3-methyl-2-butanone, 4-methyl-2-pentanone and 3-hexanone (fourfold rise). Only three compounds exhibited decreasing trend; dimethylsulfone, octanal and propanal. Conclusion: The ubiquitous urine VOCs identified within this study create a library of potential markers of human urine to be verified in further field studies, involving portable and sensitive instruments, directly applied in the field.

 


2011

Julian King, Karl Unterkofler, Susanne Teschl, Anton Amann, and Gerald Teschl. Breath gas analysis for estimating physiological processes using anesthetic monitoring as a prototypic example. Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS, pages 1001--1004, 2011. [ DOI ]

Analysis of exhaled trace gases is a novel methodology for gaining continuous and non-invasive information on the clinical state of an individual. This paper serves to explore some potential applications of breath gas analysis in anesthesia, describing a monitoring scheme for target site concentrations and cardiac output via physiological modeling and real-time breath profiles of the anesthetic agent. The rationale given here is mainly simulation-based, however, the underlying concepts are directly applicable to a routine clinical setting.

 


Pawel Mochalski, Julian King, Alexander Kupferthaler, Karl Unterkofler, Hartmann Hinterhuber, and Anton Amann. Measurement of isoprene solubility in water, human blood and plasma by multiple headspace extraction gas chromatography coupled with solid phase microextraction. Journal of Breath Research, 5(4):046010, 2011. [ DOI | http ]

The aim of this study was to determine the solubility (liquid-to-air ratios) of isoprene in water, human blood and plasma. To this end, an experimental setup combining multiple headspace extraction, solid phase microextraction and gas chromatography-mass spectrometry was applied. The water:air partition coefficients of isoprene were determined for the temperature range 4.5-37 °C and amounted to 1.171-0.277 (g mL(l)(-1)) (g mL(a)(-1))(-1). On the basis of these data, the enthalpy of volatilization was calculated as 29.46 ± 2.83 kJ mol(-1). The blood:air partition coefficients at 37 °C were determined for ten normal healthy volunteers spread around a median value of 0.95 ± 0.09 (g mL(l)(-1)) (g mL(a)(-1))(-1) and were approximately 16% lower than the plasma:air partition coefficients (1.11 ± 0.2). The applied methodology can be particularly attractive for solubility studies targeting species at very low concentrations in the solution, i.e. when headspace sample enrichment is necessary to provide sufficient measurement sensitivity and reliability. This can be especially helpful if environmental or physiological solute levels have to be considered.

 


Anton Amann, Massimo Corradi, P Mazzone, and A Mutti. Lung cancer biomarkers in exhaled breath. Expert Rev Mol Diagn, 11(2):207--217, 2011. [ DOI | http ]

Lung cancer is the leading cause of cancer-related mortality worldwide. Methods for early detection of lung cancer, such as computerized tomography scanning technology, often discover a large number of small lung nodules, posing a new problem to radiologists and chest physicians. The vast majority of these nodules will be benign, but there is currently no easy way to determine which nodules represent very early lung cancer. Adjuvant testing with PET imaging and nonsurgical biopsies has a low yield for these small indeterminate nodules, carries potential morbidity and is costly. Indeed, purely morphological criteria seem to be insufficient for distinguishing lung cancer from benign nodules at early stages with sufficient confidence, therefore false positives undergoing surgical resection frequently occur. A molecular approach to the diagnosis of lung cancer through the analysis of exhaled breath could greatly improve the specificity of imaging procedures. A biomarker-driven approach to signs or symptoms possibly due to lung cancer would represent a complementary tool aimed at ruling out (with known error probability) rather than diagnosing lung cancer. Volatile and nonvolatile components of the breath are being studied as biomarkers of lung cancer. Breath testing is noninvasive and potentially inexpensive. There is promise that an accurate lung cancer breath biomarker, capable of being applied clinically, will be developed in the near future. In this article, we summarize some of the rationale for breath biomarker development, review the published literature in this field and provide thoughts regarding future directions.

 


Martin Klieber and Anton Amann. Detektion flüchtiger organischer Verbindungen im Atemgas. Bachelorarbeit, page 67, 2011.

Betrachtung ausgewählter Markersubstanzen bei gesunden und krebskranken RaucherInnen und Nicht-RaucherInnen

 


Julian King, Karl Unterkofler, Gerald Teschl, Susanne Teschl, Helin Koc, Hartmann Hinterhuber, and Anton Amann. A mathematical model for breath gas analysis of volatile organic compounds with special emphasis on acetone. J Math Biol, 63(5):959--999, 2011. [ DOI | arXiv | http ]

Recommended standardized procedures for determining exhaled lower respiratory nitric oxide and nasal nitric oxide (NO) have been developed by task forces of the European Respiratory Society and the American Thoracic Society. These recommendations have paved the way for the measurement of nitric oxide to become a diagnostic tool for specific clinical applications. It would be desirable to develop similar guidelines for the sampling of other trace gases in exhaled breath, especially volatile organic compounds (VOCs) which may reflect ongoing metabolism. The concentrations of water-soluble, blood-borne substances in exhaled breath are influenced by: (i) breathing patterns affecting gas exchange in the conducting airways, (ii) the concentrations in the tracheo-bronchial lining fluid, (iii) the alveolar and systemic concentrations of the compound. The classical Farhi equation takes only the alveolar concentrations into account. Real-time measurements of acetone in end-tidal breath under an ergometer challenge show characteristics which cannot be explained within the Farhi setting. Here we develop a compartment model that reliably captures these profiles and is capable of relating breath to the systemic concentrations of acetone. By comparison with experimental data it is inferred that the major part of variability in breath acetone concentrations (e.g., in response to moderate exercise or altered breathing patterns) can be attributed to airway gas exchange, with minimal changes of the underlying blood and tissue concentrations. Moreover, the model illuminates the discrepancies between observed and theoretically predicted blood-breath ratios of acetone during resting conditions, i.e., in steady state. Particularly, the current formulation includes the classical Farhi and the Scheid series inhomogeneity model as special limiting cases and thus is expected to have general relevance for a wider range of blood-borne inert gases. The chief intention of the present modeling study is to provide mechanistic relationships for further investigating the exhalation kinetics of acetone and other water-soluble species. This quantitative approach is a first step towards new guidelines for breath gas analyses of volatile organic compounds, similar to those for nitric oxide.

 


2010

J Rudnicka, Pawel Mochalski, Agapios Agapiou, Milt Statheropoulos, Anton Amann, and Boguslaw Buszewski. Application of ion mobility spectrometry for the detection of human urine. Anal Bioanal Chem, 398(5):2031--2038, 2010. [ DOI | .pdf ]

The aim of the present study was to evaluate the suitability of ion mobility spectrometry (IMS) for the detection of human urine as an indication of human presence during urban search and rescue operations in collapsed buildings. To this end, IMS with a radioactive ionization source and a multicapillary column was used to detect volatile organic compounds (VOCs) emitted from human urine. A study involving a group of 30 healthy volunteers resulted in the selection of seven volatile species, namely acetone, propanal, 3-methyl-2-butanone, 2-methylpropanal, 4-heptanone, 2-heptanone and octanal, which were detected in all samples. Additionally, a preliminary study on the permeation of urine volatiles through the materials surrounding the voids of collapsed buildings was performed. In this study, quartz sand was used as a representative imitating material. Four compounds, namely 3-methyl-2-butanone, octanal, acetone and 2-heptanone, were found to permeate through the sand layers during all experiments. Moreover, their permeation times were the shortest. Although IMS can be considered as a potential technique suitable for the detection, localization and monitoring of VOCs evolved from human urine, further investigation is necessary prior to selecting field chemical methods for the early location of trapped victims.

 


Julian King, Helin Koc, Karl Unterkofler, Pawel Mochalski, Alexander Kupferthaler, Gerald Teschl, Susanne Teschl, Hartmann Hinterhuber, and Anton Amann. Physiological modeling of isoprene dynamics in exhaled breath. Journal of theoretical biology, 267(4):626--37, dec 2010. [ DOI | arXiv | http ]

Human breath contains a myriad of endogenous volatile organic compounds (VOCs) which are reflective of ongoing metabolic or physiological processes. While research into the diagnostic potential and general medical relevance of these trace gases is conducted on a considerable scale, little focus has been given so far to a sound analysis of the quantitative relationships between breath levels and the underlying systemic concentrations. This paper is devoted to a thorough modeling study of the end-tidal breath dynamics associated with isoprene, which serves as a paradigmatic example for the class of low-soluble, blood-borne VOCs. Real-time measurements of exhaled breath under an ergometer challenge reveal characteristic changes of isoprene output in response to variations in ventilation and perfusion. Here, a valid compartmental description of these profiles is developed. By comparison with experimental data it is inferred that the major part of breath isoprene variability during exercise conditions can be attributed to an increased fractional perfusion of potential storage and production sites, leading to higher levels of mixed venous blood concentrations at the onset of physical activity. In this context, various lines of supportive evidence for an extrahepatic tissue source of isoprene are presented. Our model is a first step towards new guidelines for the breath gas analysis of isoprene and is expected to aid further investigations regarding the exhalation, storage, transport and biotransformation processes associated with this important compound.

 


Julian King, Pawel Mochalski, Alexander Kupferthaler, Karl Unterkofler, Helin Koc, Wojciech Filipiak, Susanne Teschl, Hartmann Hinterhuber, and Anton Amann. Dynamic profiles of volatile organic compounds in exhaled breath as determined by a coupled PTR-MS/GC-MS study. Physiological measurement, 31(9):1169--84, sep 2010. [ DOI | .pdf ]

In this phenomenological study we focus on dynamic measurements of volatile organic compounds (VOCs) in exhaled breath under exercise conditions. An experimental setup efficiently combining breath-by-breath analyses using proton transfer reaction mass spectrometry (PTR-MS) with data reflecting the behaviour of major hemodynamic and respiratory parameters is presented. Furthermore, a methodology for complementing continuous VOC profiles obtained by PTR-MS with simultaneous SPME/GC-MS measurements is outlined. These investigations aim at evaluating the impact of breathing patterns, cardiac output or blood pressure on the observed breath concentration and allow for the detection and identification of several VOCs revealing characteristic rest-to-work transitions in response to variations in ventilation or perfusion. Examples of such compounds include isoprene, methyl acetate, butane, DMS and 2-pentanone. In particular, both isoprene and methyl acetate exhibit a drastic rise in concentration shortly after the onset of exercise, usually by a factor of about 3-5 within approximately 1 min of pedalling. These specific VOCs might also be interpreted as potentially sensitive indicators for fluctuations of blood or respiratory flow and can therefore be viewed as candidate compounds for future assessments of hemodynamics, pulmonary function and gas exchange patterns via observed VOC behaviour.

 


Anton Amann, Magdalena Ligor, Tomasz Ligor, Amel Bajtarevic, Clemens Ager, Martin Pienz, Hubert Denz, Michael Fiegl, Wolfgang Hilbe, Wolfgang Weiss, Others, Peter Lukas, Herbert Jamnig, Martin Hackl, Alfred Haidenberger, Andreas Sponring, Wojciech Filipiak, Wolfram Miekisch, Jochen K. Schubert, Jakob Troppmair, and Boguslaw Buszewski. Analysis of exhaled breath for screening of lung cancer patients. memo-Magazine of, memo(2010)(3):106--112, 2010. [ DOI | .pdf ]


Anton Amann, Konrad Eugen Schwarz, Gejza Wimmer, and Viktor Witkovský. Model based determination of detection limits for proton transfer reaction mass spectrometer. Measurement Science ..., 10(6):180--188, 2010. [ DOI | http ]


Anton Amann, A Klotz, Thomas Niederklapfer, Alexander Kupferthaler, T Werther, M Granegger, Wolfgang Lederer, M Baubin, and W Lingnau. Reduction of CPR artifacts in the ventricular fibrillation ECG by coherent line removal. Biomed Eng Online, 9(1):2, 2010. [ DOI | http ]

BACKGROUND: Interruption of cardiopulmonary resuscitation (CPR) impairs the perfusion of the fibrillating heart, worsening the chance for successful defibrillation. Therefore ECG-analysis during ongoing chest compression could provide a considerable progress in comparison with standard analysis techniques working only during "hands-off" intervals. METHODS: For the reduction of CPR-related artifacts in ventricular fibrillation ECG we use a localized version of the coherent line removal algorithm developed by Sintes and Schutz. This method can be used for removal of periodic signals with sufficiently coupled harmonics, and can be adapted to specific situations by optimal choice of its parameters (e.g., the number of harmonics considered for analysis and reconstruction). Our testing was done with 14 different human ventricular fibrillation (VF) ECGs, whose fibrillation band lies in a frequency range of [1 Hz, 5 Hz]. The VF-ECGs were mixed with 12 different ECG-CPR-artifacts recorded in an animal experiment during asystole. The length of each of the ECG-data was chosen to be 20 sec, and testing was done for all 168 = 14 x 12 pairs of data. VF-to-CPR ratio was chosen as -20 dB, -15 dB, -10 dB, -5 dB, 0 dB, 5 dB and 10 dB. Here -20 dB corresponds to the highest level of CPR-artifacts. RESULTS: For non-optimized coherent line removal based on signals with a VF-to-CPR ratio of -20 dB, -15 dB, -10 dB, -5 dB and 0 dB, the signal-to-noise gains (SNR-gains) were 9.3 +/- 2.4 dB, 9.4 +/- 2.4 dB, 9.5 +/- 2.5 dB, 9.3 +/- 2.5 dB and 8.0 +/- 2.7 (mean +/- std, n = 168), respectively. Characteristically, an original VF-to-CPR ratio of -10 dB, corresponds to a variance ratio var(VF):var(CPR) = 1:10. An improvement by 9.5 dB results in a restored VF-to-CPR ratio of -0.5 dB, corresponding to a variance ratio var(VF):var(CPR) = 1:1.1, the variance of the CPR in the signal being reduced by a factor of 8.9. DISCUSSION: The localized coherent line removal algorithm uses the information of a single ECG channel. In contrast to multi-channel algorithms, no additional information such as thorax impedance, blood pressure, or pressure exerted on the sternum during CPR is required. Predictors of defibrillation success such as mean and median frequency of VF-ECGs containing CPR-artifacts are prone to being governed by the harmonics of the artifacts. Reduction of CPR-artifacts is therefore necessary for determining reliable values for estimators of defibrillation success. CONCLUSIONS: The localized coherent line removal algorithm reduces CPR-artifacts in VF-ECG, but does not eliminate them. Our SNR-improvements are in the same range as offered by multichannel methods of Rheinberger et al., Husoy et al. and Aase et al. The latter two authors dealt with different ventricular rhythms (VF and VT), whereas here we dealt with VF, only. Additional developments are necessary before the algorithm can be tested in real CPR situations.

 


Beata Wzorek, Pawel Mochalski, I Sliwka, and Anton Amann. Application of GC-MS with a SPME and thermal desorption technique for determination of dimethylamine and trimethylamine in gaseous samples for medical diagnostic purposes. Journal of breath research, 4(2):26002, 2010. [ DOI | http ]

Biogenic amines are interesting compounds which may be of use for medical diagnosis or therapeutic monitoring. The present paper deals with the problems that occur with concentration determination of dimethylamine (DMA) and trimethylamine (TMA). These occur in the breath of people suffering from renal disease. The measurement of amines present in trace concentrations requires the application of suitable analytical methods during sampling, storage and preconcentration. This is particularly so due to their polar and basic properties. In this paper, the application of solid phase microextraction (SPME) and thermal desorption (TD) with subsequent measurement by GC-MS for the determination of amines is discussed. For DMA, preconcentration by SPME did not give satisfactory results. TMA may be analysed using SPME preconcentration with an LOD of 1.5 ppb. Thermal desorption with Tenax as the adsorbing material allows reliable concentration determination for TMA (LOD = 0.5 ppb) and DMA (LOD = 4.6 ppb). DMA cannot be stored reliably in Tedlar bags and longer storage on Tenax (with subsequent TD) does not give good repeatability of results. For TMA, storage can be done on Tenax or in bags, the best results for the latter being achieved with Flex Foil bags.

 


Sabine Kischkel, Wolfram Miekisch, Annika Sawacki, Eva M. Straker, Phillip Trefz, Anton Amann, and Jochen K. Schubert. Breath biomarkers for lung cancer detection and assessment of smoking related effects--confounding variables, influence of normalization and statistical algorithms. Clinica chimica acta; international journal of clinical chemistry, 411(21-22):1637--44, nov 2010. [ DOI | http ]

Up to now, none of the breath biomarkers or marker sets proposed for cancer recognition has reached clinical relevance. Possible reasons are the lack of standardized methods of sampling, analysis and data processing and effects of environmental contaminants.

 


Andreas Sponring, Wojciech Filipiak, Clemens Ager, Jochen K. Schubert, Wolfram Miekisch, Anton Amann, and Jakob Troppmair. Analysis of volatile organic compounds (VOCs) in the headspace of NCI-H1666 lung cancer cells. Cancer biomarkers : section A of Disease markers, 7(3):153--61, jan 2010. [ DOI | http ]

Analysis of volatile organic compounds (VOCs) provides an elegant approach for cancer screening and disease monitoring, whose use is currently limited by a lack of validated cancer-derived metabolites, which may serve as biomarkers. The aim of the experiments presented here was to investigate the release and consumption of VOCs from the non small cell lung cancer cell line NCI-H1666, which was originally derived from a bronchoalveolar carcinoma.Following detachment by trypsinization suspended cells were incubated in a sealed fermenter for 21 hours. 200 ml of headspace from the cell culture were sampled, diluted with dry, highly purified air and preconcentrated by adsorption on three different solid sorbents with increasing adsorption strength. VOC-analysis was performed by thermodesorption-gas chromatography mass spectrometry (TD-GC-MS). In contrast to our previous studies experiments with NCI-H1666 cells only confirmed the consumption of several aldehydes, n-butyl acetate and the ethers methyl tert-butyl ether and ethyl tert-butyl ether, but no unequivocal release of VOCs was observed. Together with our previously published work these data indicate that the consumption of certain VOCs is commonly observed while their release shows cell line-restricted patterns, whose underlying causes are unknown.

 


Wojciech Filipiak, Andreas Sponring, Anna Filipiak, Clemens Ager, Jochen K. Schubert, Wolfram Miekisch, Anton Amann, and Jakob Troppmair. TD-GC-MS analysis of volatile metabolites of human lung cancer and normal cells in vitro. Cancer epidemiology, biomarkers & prevention : a publication of the American Association for Cancer Research, cosponsored by the American Society of Preventive Oncology, 19(1):182--95, jan 2010. [ DOI | http ]

The aim of this study was to confirm the existence of volatile organic compounds (VOC) specifically released or consumed by the lung cancer cell line A549, which could be used in future screens as biomarkers for the early detection of lung cancer. For comparison, primary human bronchial epithelial cells (HBEpC) and human fibroblasts (hFB) were included. VOCs were detected in the headspace of cell cultures or medium controls following adsorption on solid sorbents, thermodesorption, and analysis by gas chromatography mass spectrometry. Using this approach, we identified VOCs that behaved similarly in normal and transformed cells. Thus, concentrations of 2-pentanone and 2,4-dimethyl-1-heptene were found to increase in the headspace of A549, HBEpC, and hFB cell cultures. In addition, the ethers methyl tert-butyl ether and ethyl tert-butyl ether could be detected at elevated levels in the case of A549 cells and one of the untransformed cell lines. However, especially branched hydrocarbons and alcohols were seen increased more frequently in untransformed than A549 cells. A big variety of predominantly aldehydes and the ester n-butyl acetate were found at decreased concentrations in the headspace of all cell lines tested compared with medium controls. Again, more different aldehydes were found to be decreased in hFB and HBEpC cells compared with A549 cells and 2-butenal was metabolized exclusively by both control cell lines. These data suggest that certain groups of VOCs may be preferentially associated with the transformed phenotype.

 


2009

Andreas Sponring, Wojciech Filipiak, Tomáš Mikoviny, Clemens Ager, Jochen K. Schubert, Wolfram Miekisch, Anton Amann, and Jakob Troppmair. Release of volatile organic compounds from the lung cancer cell line NCI-H2087 in vitro. Anticancer, 29(1):419--426, jan 2009. [ http ]

AIM: The aim of this work was to confirm the existence of volatile organic compounds (VOCs) specifically released by lung cancer cells. MATERIALS AND METHODS: NCI-H2087 cells were trypsinized and 100 x 10(6) cells were incubated in a sealed fermenter overnight. Samples from the headspace of the culture vessel were collected with simultaneous preconcentration by adsorption on solid sorbents and subsequently thermodesorbed for analysis by gas chromatography mass spectrometry (GC-MS). RESULTS: The results showed a significant increase in the concentration of 2-ethyl-1-hexanol and 2-methylpentane in the headspace as compared with medium controls. 2-Methylpentane is also found in exhaled breath of lung cancer patients in contrast to that from healthy volunteers. Statistically significantly lower abundances of acetaldehyde, 2-methylpropanal, 3-methylbutanal, 2-methylbutanal and butyl acetate were found. CONCLUSION: Our findings demonstrate that certain compounds can be cancer cell derived and thus may be indicative of the presence of a tumor. Some compounds were not released but seem to be consumed by cancer cells.

 


Pawel Mochalski, Beata Wzorek, Ireneusz Śliwka, and Anton Amann. Improved pre-concentration and detection methods for volatile sulphur breath constituents. Journal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences, 877(20-21):1856--1866, 2009. [ DOI | http ]

Suitability of different types of pre-concentration (solid phase microextraction and sorbent trapping) and detection (flame photometric detector (FPD) and mass selective detector (MSD)) for gas chromatographic determination of sulphur-containing compounds (H2S, MeSH, EtSH, DMS, COS and CS2) in breath-gas was assessed in this study. Several factors like influence of humidity, influence of oxygen, or stability of target compounds in extraction vessels (SPME vials and sorbent tubes) were investigated. Despite poor stability of VSCs in SPME vials and matrix effects (unfavorable influence of humidity), SPME was found to be a fast and reliable enrichment method, which coupled with mass selective detector provided satisfactory LODs of target compounds at the ppt level (from 0.15 ppb for CS2 to 2.3 ppb for H2S). Application of sorbent trapping with two-bed sorbent tubes containing Tenax TA and Carboxen 1000 gave excellent LODs (0.03-0.3 ppb for 200 ml sample and MSD). Stability of investigated VSCs in sorbents was found to be very poor (30-40% losses after 2 h). FPD showed satisfactory sensitivity only when it was coupled with sorbent trapping. Breath samples were collected into Tedlar bags in a CO2-controlled manner. Humidity was removed during sampling (permeation dryer - Nafion) to avoid unfavorable water dependent effects during analysis. 2009 Elsevier B.V. All rights reserved.

 


Jens Herbig and Anton Amann. Proton transfer reaction-mass spectrometry applications in medical research. Journal of breath research, 3(2):20201, 2009. [ DOI | http ]

Gathering information about a subject's physiological and pathophysiological condition from the `smell' of breath is an idea that dates back to antiquity. This intriguing concept of non-invasive diagnosis has been revitalized by `exhaled breath analysis' in recent decades. A main driving force was the development of sensitive and versatile gas-chromatographic and mass-spectrometric instruments for trace gas analysis. Ironically, only non-smelling constituents of breath, such as O(2), CO(2), H(2), and NO have so far been included in routine clinical breath analysis. The `smell' of human breath, on the other hand, arises through a combination of volatile organic compounds (VOCs) of which several hundred have been identified to date. Most of these volatiles are systemic and are released in the gas-exchange between blood and air in the alveoli. The concentration of these compounds in the alveolar breath is related to the respective concentrations in blood. Measuring VOCs in exhaled breath allows for screening of disease markers, studying the uptake and effect of medication (pharmacokinetics), or monitoring physiological processes. There is a range of requirements for instruments for the analysis of a complex matrix, such as human breath. Mass-spectrometric techniques are particularly well suited for this task since they offer the possibility of detecting a large variety of interesting compounds. A further requirement is the ability to measure accurately in the concentration range of breath VOCs, i.e. between parts-per-trillion (pptv) and parts-per-million (ppmv) range. In the mid 1990's proton transfer reaction-mass spectrometry (PTR-MS) was developed as a powerful and promising tool for the analysis of VOCs in gaseous media. Soon thereafter these instruments became commercially available to a still growing user community and have now become standard equipment in many fields including environmental research, food and flavour science, as well as life sciences. Their high sensitivity for VOCs with detection limits down to sub-pptv levels without pre-concentration and their highly linear signal response over seven orders of magnitude make PTR-MS instruments valuable tools for exhaled breath analysis. The `soft' chemical ionization process in PTR-MS largely avoids fragmentation, providing interpretable spectra without pre-separation. This is especially important for complex gas mixtures such as breath. Even more interesting, PTR-MS instruments analyse a gas sample in real-time and do not require any sample pre-treatment. This offers the possibility for online breath analysis with breath-to-breath resolution. This special issue on PTR-MS applications in medical research contains articles exploring different medical applications of PTR-MS. These applications include screening studies, where the breath composition of a large number of patients is investigated to, e.g., determine influences of demographic data on breath concentrations (Schwarz et al 2009 J. Breath Res. 3 027003). In online monitoring studies the breath of one subject is continuously measured, e.g., to study rapid changes in breath volatiles under physical exercise (King et al 2009 J. Breath Res. 3 027006). Other papers address more elementary breath research and discuss the interpretation of exhaled breath composition in the presence of fragmenting and overlapping compounds (Schwarz et al 2009 J. Breath Res. 3 027002), examine the different causes of variability in the measurement of breath samples (Thekedar et al 2009 J. Breath Res. 3 027007), and compare blood and breath concentrations directly (O'Hara et al 2009 J. Breath Res. 3 027005). Potential sources for breath markers are also explored, by analysing the head-space emissions from microbial culture samples (O'Hara and Mayhew 2009 J. Breath Res. 3 027001). Finally, a recent technological advancement in PTR-MS technology promises several advantages especially for breath gas analysis, which is demonstrated by on-line breath sampling with a PTR-time-of-flight (PTR-TOF) instrument (Herbig et al 2009 J. Breath Res. 3 027004).

 


Konrad Eugen Schwarz, Wojciech Filipiak, and Anton Amann. Determining concentration patterns of volatile compounds in exhaled breath by PTR-MS. Journal of Breath Research, 3(2):027002, 2009. [ DOI ]

Proton-transfer-reaction mass spectrometry (PTR-MS) is a convenient technique for fast analysis of exhaled breath without prior sample preparation. Since compounds are not separated prior to analysis as in gas chromatography mass spectrometry (GC-MS), and since protonated molecules may fragment, relatively complex spectra may arise, which are not easily interpreted in a quantitative way. We calibrated 21 different compounds of importance for exhaled breath analysis, based on the respective pure standards diluted with nitrogen. These calibration measurements included determination of the fragmentation pattern of each compound under dry conditions and in the absence of CO(2). Even though the fragmentation pattern may be predicted in a qualitative manner, the quantitative details may depend on water and CO(2) content. This is exemplarily shown for isoprene. Out of the selected 21 compounds, 11 compounds showed substantial fragmentation (fragments proportion 10%). Fragmentation of several volatile organic compounds (VOCs) in the drift tube of PTR-MS has been previously observed (Buhr et al 2002 Int. J. Mass Spectrom. 221 1-7; Taipale et al 2008 Atmos. Chem. Phys. Discuss. 8 9435-75; Hewitt et al 2003 J. Environ. Monit. 51-7; Warneke et al 2003 Environ. Sci. Technol. 37 2494-501; de Gouw and Warneke 2007 Mass Spectrom. Rev. 26 223-57; Pozo-Bayon et al 2008 J. Agric. Food Chem. 56 5278-84) and calibration factors for several compounds at corresponding mass-to-charge ratios have been calculated. In this paper, besides the calibration factors, the proportions of substantial fragments are also taken into account for a correct quantification in the case of overlapping signals. The spectrum of a mixture of the considered 21 compounds may be simulated. Conversely, the determination of concentrations from the spectrum of such a mixture is a linear optimization problem, whose solution is determined here using the simplex algorithm.

 


Tomasz Ligor, Clemens Ager, Konrad Eugen Schwarz, Wojciech Zebrowski, Anton Amann, and Boguslaw Buszewski. Comparison of proton transfer reaction-mass spectrometry and gas chromatography-mass spectrometry in analysis of breath samples. Chemia Analityczna, 54(3):329--338, 2009. [ http ]

Proton transfer reaction-mass spectrometry (PTR-MS) and gas chromatography-mass spectrometry (GC-MS) methods were compared and used for determination of volatile organic compounds in breath of patients suffering from COPD (chronic obstructive pulmonary disease). The working ranges available in PTR-MS and GC-MS were 0.3-5.8 nmol dm-3 and 0.9-1.8 nmol dm-3,respectively. Principal component analysis was used for comparison of sensitivity of PTR-MS and GC-MS towards particular compounds (alkanes, ketones and aldehydes).

 


Magdalena Ligor, Tomasz Ligor, Amel Bajtarevic, Clemens Ager, Martin Pienz, Martin Klieber, Hubert Denz, Michael Fiegl, Wolfgang Hilbe, Wolfgang Weiss, Peter Lukas, Herbert Jamnig, Martin Hackl, Boguslaw Buszewski, Wolfram Miekisch, Jochen K. Schubert, and Anton Amann. Determination of volatile organic compounds in exhaled breath of patients with lung cancer using solid phase microextraction and gas chromatography mass spectrometry. Clin Chem Lab Med, 47(5):550--560, jan 2009. [ DOI | http ]

BACKGROUND: Analysis of exhaled breath is a promising diagnostic method. Sampling of exhaled breath is non-invasive and can be performed as often as considered desirable. There are indications that the concentration and presence of certain of volatile compounds in exhaled breath of lung cancer patients is different from concentrations in healthy volunteers. This might lead to a future diagnostic test for lung cancer. METHODS: Exhaled breath samples from 65 patients with different stages of lung cancer and undergoing different treatment regimes were analysed. Mixed expiratory and indoor air samples were collected. Solid phase microextraction (SPME) with carboxen/polydimethylsiloxane (CAR/PDMS) sorbent was applied. Compounds were analysed by means of gas chromatography (GC) and mass spectrometry (MS). RESULTS: The method we used allowed identification with the spectral library of 103 compounds showing at least 15% higher concentration in exhaled breath than in inhaled air. Among those 103 compounds, 84 were confirmed by determination of the retention time using standards based on the respective pure compound. Approximately, one third of the compounds detected were hydrocarbons. We found aromatic hydrocarbons, alcohols, aldehydes, ketones, esters, ethers, sulfur compounds, nitrogen-containing compounds and halogenated compounds. Acetonitrile and benzene were two of 10 compounds which correlated with smoking behaviour. A comparison of results from cancer patients with those of 31 healthy volunteers revealed differences in the concentration and presence of certain compounds. The sensitivity for detection of lung cancer patients based on eight different compounds not seen in exhaled breath of healthy volunteers was 51% and the specificity was 100%. These eight potential markers for detection of lung cancer are 1-propanol, 2-butanone, 3-butyn-2-ol, benzaldehyde, 2-methyl-pentane, 3-methyl-pentane, n-pentane and n-hexane. CONCLUSIONS: SPME is a relatively insensitive method and compounds not observed in exhaled breath may be present at a concentration lower than LOD. The main achievement of the present work is the validated identification of compounds observed in exhaled breath of lung cancer patients. This identification is indispensible for future work on the biochemical sources of these compounds and their metabolic pathways.

 


M E O'Hara, Tom H. Clutton-Brock, Stuart Green, and Chris A. Mayhew. Endogenous volatile organic compounds in breath and blood of healthy volunteers: examining breath analysis as a surrogate for blood measurements. Journal of Breath Research, 3(2):027005, jun 2009. [ DOI | http ]

To investigate the premise that levels of endogenous volatile organic compounds (VOC) in breath reflect those in blood, the concentration of acetone and isoprene were measured in radial arterial blood, peripheral venous blood and breath samples from ten healthy volunteers. Coefficients of repeatability as a percentage of mean are less than 30% in breath but greater than 70% in blood. The volunteer-mean ratios of arterial to venous blood concentration are 1.4 (0.9-2.1) for acetone and 0.55 (0.3-1.0) for isoprene. Concentration in breath showed a significant inter-subject correlation with concentration in arterial blood (CAB) for acetone but not for isoprene. Arterial blood/breath ratios are 580 (280-1060) for acetone and 0.47 (0.22-0.77) for isoprene. The sample-mean blood/breath ratio was used to calculate an estimate of CAB and the standard deviation of this estimate was lower than that of arterial blood measured directly. For most subjects, estimated CAB was within uncertainty limits of the actual CAB. Owing to the poor repeatability of VOC concentrations from consecutive blood samples, and the capacitive effects of the lung, this study suggests that breath VOC measurements may provide a more consistent measure than blood measurements for investigating underlying physiological function or pathology within individuals.

 


Pawel Mochalski, Beata Wzorek, I Sliwka, and Anton Amann. Suitability of different polymer bags for storage of volatile sulphur compounds relevant to breath analysis. J Chromatogr B Analyt Technol Biomed Life Sci, 877(3):189--196, 2009. [ DOI | http ]

Suitability of five polymer sampling containers (Nalophan, transparent Tedlar, black layered Tedlar, Teflon and FlexFoil) for sampling and storage of six relevant to breath analysis volatile sulphur compounds: H(2)S, MeSH, EtSH, COS, DMS and CS(2) was studied using solid phase microextraction (SPME) and gas chromatography coupled with mass spectrometry (GC-MS). Investigations were made with respect to the several factors like: recovery, background, influence of light, ageing effect and matrix effects. Additionally, the optimal reusability conditions were established. Findings suggest analyzing the breath VSCs within 6h after sampling. Flexfoil bags were found to be the best choice for the VSCs storage up to 24h (recovery about 90% with the exception of DMS). For shorter storing times (6-8h) transparent Tedlar is a good alternative for Flexfoil (losses up to 10%).

 


Boguslaw Buszewski, Agnieszka Ulanowska, Tomasz Ligor, Natalia Denderz, and Anton Amann. Analysis of exhaled breath from smokers, passive smokers and non-smokers by solidphase microextraction gas chromatography/mass spectrometry. Biomedical Chromatography, 23(5):551--556, 2009. [ DOI | http ]

In this study, 38 samples of expired air were collected and analyzed from 20 non-smoking volunteers, four passive smokers and 14 smokers (21 women and 17 men). Measurements were carried out using solid-phase microextraction (SPME) as an isolation and preconcentration technique. The determination and identification were accomplished by gas chromatography coupled with mass spectrometry (GC/MS). Our data showed that ca 32% of all identified compounds in the breath of healthy non-smokers were saturated hydrocarbons. In the breath of smoking and passive smoking volunteers hydrocarbons were predominant, but also present were more exogenous analytes such as furan, acetonitrile and benzene than in the breath of non-smokers. Acetonitrile, furan, 3-methylfuran, 2,5-dimethylfuran, 2-butanone, octane and decane were identified in breath of smoking and passive smoking persons.

 


Amel Bajtarevic, Clemens Ager, Martin Pienz, Martin Klieber, Konrad Eugen Schwarz, Magdalena Ligor, Tomasz Ligor, Wojciech Filipiak, Hubert Denz, Michael Fiegl, Wolfgang Hilbe, Wolfgang Weiss, Peter Lukas, Herbert Jamnig, Martin Hackl, Alfred Haidenberger, Boguslaw Buszewski, Wolfram Miekisch, Jochen K. Schubert, Anton Amann, Others, Wolfgang Hilbe, Wolfgang Weiss, Peter Lukas, Herbert Jamnig, Martin Hackl, Alfred Haidenberger, Boguslaw Buszewski, Wolfram Miekisch, Jochen K. Schubert, and Anton Amann. Noninvasive detection of lung cancer by analysis of exhaled breath. BMC cancer, 9(1):348, jan 2009. [ DOI | http ]

BACKGROUND: Lung cancer is one of the leading causes of death in Europe and the western world. At present, diagnosis of lung cancer very often happens late in the course of the disease since inexpensive, non-invasive and sufficiently sensitive and specific screening methods are not available. Even though the CT diagnostic methods are good, it must be assured that "screening benefit outweighs risk, across all individuals screened, not only those with lung cancer". An early non-invasive diagnosis of lung cancer would improve prognosis and enlarge treatment options. Analysis of exhaled breath would be an ideal diagnostic method, since it is non-invasive and totally painless. METHODS: Exhaled breath and inhaled room air samples were analyzed using proton transfer reaction mass spectrometry (PTR-MS) and solid phase microextraction with subsequent gas chromatography mass spectrometry (SPME-GCMS). For the PTR-MS measurements, 220 lung cancer patients and 441 healthy volunteers were recruited. For the GCMS measurements, we collected samples from 65 lung cancer patients and 31 healthy volunteers. Lung cancer patients were in different disease stages and under treatment with different regimes. Mixed expiratory and indoor air samples were collected in Tedlar bags, and either analyzed directly by PTR-MS or transferred to glass vials and analyzed by gas chromatography mass spectrometry (GCMS). Only those measurements of compounds were considered, which showed at least a 15% higher concentration in exhaled breath than in indoor air. Compounds related to smoking behavior such as acetonitrile and benzene were not used to differentiate between lung cancer patients and healthy volunteers. RESULTS: Isoprene, acetone and methanol are compounds appearing in everybody's exhaled breath. These three main compounds of exhaled breath show slightly lower concentrations in lung cancer patients as compared to healthy volunteers (p 0.01 for isoprene and acetone, p = 0.011 for methanol; PTR-MS measurements). A comparison of the GCMS-results of 65 lung cancer patients with those of 31 healthy volunteers revealed differences in concentration for more than 50 compounds. Sensitivity for detection of lung cancer patients based on presence of (one of) 4 different compounds not arising in exhaled breath of healthy volunteers was 52% with a specificity of 100%. Using 15 (or 21) different compounds for distinction, sensitivity was 71% (80%) with a specificity of 100%. Potential marker compounds are alcohols, aldehydes, ketones and hydrocarbons. CONCLUSION: GCMS-SPME is a relatively insensitive method. Hence compounds not appearing in exhaled breath of healthy volunteers may be below the limit of detection (LOD). PTR-MS, on the other hand, does not need preconcentration and gives much more reliable quantitative results then GCMS-SPME. The shortcoming of PTR-MS is that it cannot identify compounds with certainty. Hence SPME-GCMS and PTR-MS complement each other, each method having its particular advantages and disadvantages. Exhaled breath analysis is promising to become a future non-invasive lung cancer screening method. In order to proceed towards this goal, precise identification of compounds observed in exhaled breath of lung cancer patients is necessary. Comparison with compounds released from lung cancer cell cultures, and additional information on exhaled breath composition in other cancer forms will be important.

 


S Erhart, Anton Amann, D Karall, G Edlinger, E Haberlandt, Alex Schmid, Wojciech Filipiak, Pawel Mochalski, K Rostasy, and Sabine Scholl-Bürgi. 3-Heptanone as a potential new marker for valproic acid therapy. Journal of breath research, 3(1):016004 (6 pp), 2009. [ DOI | http ]

Breath gas samples from 27 patients with epilepsy (17 male and 10 female patients; mean age: 9.7 years, median age: 8.2 years, SD: +/- 4.2 years) were screened via proton transfer reaction mass spectrometry. The patients were treated with valproic acid (VPA) therapy, and blood samples for determination of VPA concentrations were surveyed. All patients showed significantly elevated concentrations of 3-heptanone (C(7)H(14)O) in exhaled breath gas (mean: 14.7 ppb, median: 13.8 ppb SD: +/- 5.7 ppb). In human breath, several hundred different volatile organic compounds can be detected. In breath of patients with valproic acid monotherapy, an increased concentration of 3-heptanone was measured. The objective of this study was to investigate if serum VPA concentrations correlate with 3-heptanone concentrations in exhaled breath. In conclusion, 3-heptanone in breath gas is significantly elevated in patients treated with the valproic acid, but does not correlate significantly with the VPA concentrations in serum or the daily dose of this drug.

 


Konrad Eugen Schwarz, Alex Pizzini, Barbora Arendacká, K Zerlauth, Wojciech Filipiak, Alex Schmid, Alexander Dzien, S Neuner, Monika Lechleitner, Sabine Scholl-Bürgi, Wolfram Miekisch, Jochen K. Schubert, Karl Unterkofler, Viktor Witkovský, Günter Gastl, and Anton Amann. Breath acetone—aspects of normal physiology related to age and gender as determined in a PTR-MS study. Journal of Breath Research, 3(2):027003, jun 2009. [ DOI | http ]

The present study was performed to determine the variations of breath acetone concentrations with age, gender and body-mass index (BMI). Previous investigations were based on a relatively small cohort of subjects (see Turner et al 2006 Physiol. Meas. 27 321-37). Since exhaled breath analysis is affected by considerable variation, larger studies are needed to get reliable information about the correlation of concentrations of volatiles in breath when compared with age, gender and BMI. Mixed expiratory exhaled breath was sampled using Tedlar bags. The concentrations of a mass-to-charge ratio (m/z) of 59, attributed to acetone, were then determined using proton transfer reaction-mass spectrometry. Our cohort, consisting of 243 adult volunteers not suffering from diabetes, was divided into two groups: one that fasted overnight prior to sampling (215 volunteers) and the other without a dietary control (28 volunteers). In addition, we considered a group of 44 healthy children (5-11 years old).The fasted subjects' concentrations of acetone ranged from 177 ppb to 2441 ppb, with an overall geometric mean (GM) of 628 ppb; in the group without a dietary control, the subjects' concentrations ranged from 281 ppb to 1246 ppb with an overall GM of 544 ppb. We found no statistically significant shift between the distributions of acetone levels in the breath of males and females in the fasted group (the Wilcoxon-Mann-Whitney test yielded p = 0.0923, the medians being 652 ppb and 587 ppb). Similarly, there did not seem to be a difference between the acetone levels of males and females in the group without a dietary control. Aging was associated with a slight increase of acetone in the fasted females; in males the increase was not statistically significant. Compared with the adults (a merged group), our group of children (5-11 years old) showed lower concentrations of acetone (p 0.001), with a median of 263 ppb. No correlation was found between the acetone levels and BMI in adults. Our results extend those of Turner et al's (2006 Physiol. Meas. 27 321-37), who analyzed the breath of 30 volunteers (without a dietary control) by selected ion flow tube-mass spectrometry. They reported a positive correlation with age (but without statistical significance in their cohort, with p = 0.82 for males and p = 0.45 for females), and, unlike us, arrived at a p-value of 0.02 for the separation of males and females with respect to acetone concentrations. Our median acetone concentration for children (5-11 years) coincides with the median acetone concentration of young adults (17-19 years) reported by Spanel et al (2007 J. Breath Res. 1 026001).

 


S M Giacomuzzi, Y Riemer, M Pavlic, Alex Schmid, Hartmann Hinterhuber, and Anton Amann. Applications of breath gas analysis in addiction medicine--preliminary results. Subst Use Misuse, 44(2):301--304, 2009. [ DOI | http ]


Julian King, Alexander Kupferthaler, Karl Unterkofler, Helin Koc, Susanne Teschl, Gerald Teschl, Wolfram Miekisch, Jochen K. Schubert, Hartmann Hinterhuber, and Anton Amann. Isoprene and acetone concentration profiles during exercise on an ergometer. Journal of breath research, 3(2):27006, 2009. [ DOI | http ]

A real-time recording setup combining exhaled breath volatile organic compound (VOC) measurements by proton transfer reaction-mass spectrometry (PTR-MS) with hemodynamic and respiratory data is presented. Continuous automatic sampling of exhaled breath is implemented on the basis of measured respiratory flow: a flow-controlled shutter mechanism guarantees that only end-tidal exhalation segments are drawn into the mass spectrometer for analysis. Exhaled breath concentration profiles of two prototypic compounds, isoprene and acetone, during several exercise regimes were acquired, reaffirming and complementing earlier experimental findings regarding the dynamic response of these compounds reported by Senthilmohan et al (2000 Redox Rep. 5 151-3) and Karl et al (2001 J. Appl. Physiol. 91 762-70). While isoprene tends to react very sensitively to changes in pulmonary ventilation and perfusion due to its lipophilic behavior and low Henry constant, hydrophilic acetone shows a rather stable behavior. Characteristic (median) values for breath isoprene concentration and molar flow, i.e., the amount of isoprene exhaled per minute are 100 ppb and 29 nmol min(-1), respectively, with some intra-individual day-to-day variation. At the onset of exercise breath isoprene concentration increases drastically, usually by a factor of approximately 3-4 within about 1 min. Due to a simultaneous increase in ventilation, the associated rise in molar flow is even more pronounced, leading to a ratio between peak molar flow and molar flow at rest of approximately 11. Our setup holds great potential in capturing continuous dynamics of non-polar, low-soluble VOCs over a wide measurement range with simultaneous appraisal of decisive physiological factors affecting exhalation kinetics. In particular, data appear to favor the hypothesis that short-term effects visible in breath isoprene levels are mainly caused by changes in pulmonary gas exchange patterns rather than fluctuations in endogenous synthesis.

 


2008

Wojciech Filipiak, Andreas Sponring, Tomáš Mikoviny, Clemens Ager, Jochen K. Schubert, Wolfram Miekisch, Anton Amann, and Jakob Troppmair. Release of volatile organic compounds (VOCs) from the lung cancer cell line CALU-1 in vitro. Cancer Cell Int, 8(1):17, nov 2008. [ DOI | http ]

BACKGROUND: The aim of this work was to confirm the existence of volatile organic compounds (VOCs) specifically released or consumed by lung cancer cells. METHODS: 50 million cells of the human non-small cell lung cancer (NSCLC) cell line CALU-1 were incubated in a sealed fermenter for 4 h or over night (18 hours). Then air samples from the headspace of the culture vessel were collected and preconcentrated by adsorption on solid sorbents with subsequent thermodesorption and analysis by means of gas chromatography mass spectrometry (GC-MS). Identification of altogether 60 compounds in GCMS measurement was done not only by spectral library match, but also by determination of retention times established with calibration mixtures of the respective pure compounds. RESULTS: The results showed a significant increase in the concentrations of 2,3,3-trimethylpentane, 2,3,5-trimethylhexane, 2,4-dimethylheptane and 4-methyloctane in the headspace of CALU-1 cell culture as compared to medium controls after 18 h. Decreased concentrations after 18 h of incubation were found for acetaldehyde, 3-methylbutanal, butyl acetate, acetonitrile, acrolein, methacrolein, 2-methylpropanal, 2-butanone, 2-methoxy-2-methylpropane, 2-ethoxy-2-methylpropane, and hexanal. CONCLUSION: Our findings demonstrate that certain volatile compounds can be cancer-cell derived and thus indicative of the presence of a tumor, whereas other compounds are not released but seem to be consumed by CALU-1 cells.

 


Ž Krkošová, R Kubinec, L Soják, and Anton Amann. Temperature-programmed gas chromatography linear retention indices of all C4-C30 monomethylalkanes on methylsilicone OV-1 stationary phase. Contribution towards a better understanding of volatile organic compounds in exhaled breath. J Chromatogr A, 1179(1):59--68, 2008. [ DOI | http ]

Monomethylated alkanes have been proposed to be contained in exhaled breath, their concentration pattern serving for identification of lung carcinoma, breast carcinoma and rejection of foreign tissue after heart transplant rejection. Improving the accuracy of identification for monomethylated alkanes will enhance work on their biochemical background which presently is unknown. The programmed temperature linear retention indices of all 196 C(4)-C(30) monomethylalkanes on OV-1 stationary phase were measured with an average repeatability of +/-0.07 index units (i.u.). The mixture of C(9)-C(30) monomethylalkanes was prepared by methylene insertion reaction to C(8)-C(29)n-alkanes mixture. The preliminary identification of monomethylalkanes was performed on the basis of the dependence of homomorphy factors on the number of carbon atoms of individual homologous series of monomethylalkanes (retention indices extrapolated with s=0.15 i.u.). The prediction of retention of isomers with new position of methyl group beginning at higher carbon atoms number, as well as for second, third, fourth, etc., member of homologous series allowed the dependence H(P)=f(C(n)) for first, second, third, etc., members of beginning homologous of monomethylalkane series (retention indices extrapolated with s=0.17 i.u.). The identification was confirmed by mass spectrometry. All gas chromatographic unseparated monomethylalkane isomers with methyl-group near the middle of molecule carbon chain were resoluted by mass spectrometric deconvolution. Obtained regular dependences H(P)=f(C(n)) allow precise retention prediction of monomethylalkanes C(30).

 


S M Giacomuzzi, Y Riemer, J Madia, M Pavlic, Pawel Mochalski, Alex Schmid, Hartmann Hinterhuber, Tomasz Ligor, and Anton Amann. Determination of the concentration levels of acetonitrile, benzene and toluene in exhaled breath of opioid-dependent persons: a contribution to addiction medicine. page preprint, 2008.


E Aguilera-Herrador, S Cardenas, Veronika Ruzsanyi, S Sielemann, and M Valcarcel. Evaluation of a new miniaturized ion mobility spectrometer and its coupling to fast gas chromatography multicapillary columns. Journal of Chromatography A, 1214(1-2):143--150, 2008. [ DOI | http ]

A new miniaturized ion mobility spectrometer (mu IMS) has been constructed and evaluated. The results obtained for a selected group of volatile organic compounds have been compared with those provided by an IMS of bigger dimensions with satisfactory conclusions. Moreover, its performance in terms of analytes resolution is better than those values given for other miniaturized instruments described in the literature. The possibility of an adjustable shutter opening time and the low intensity of the radiation source are also remarkable characteristics of the miniaturized detector. The small size of the mu IMS enables its portability and its wide-range of applications as a sensor device. Six different substances supposed as respiratory markers of different diseases have been selected to prove the feasibility of the spectrometer constructed. (c) 2008 Elsevier B.V. All rights reserved.

 


K Rheinberger, T Steinberger, Karl Unterkofler, M Baubin, A Klotz, and Anton Amann. Removal of CPR artifacts from the ventricular fibrillation ECG by adaptive regression on lagged reference signals. IEEE Trans Biomed Eng, 55(1):130--137, 2008. [ DOI | http ]

BACKGROUND AND OBJECTIVE: Removing cardiopulmonary resuscitation (CPR)-related artifacts from human ventricular fibrillation (VF) electrocardiogram (ECG) signals provides the possibility to continuously detect rhythm changes and estimate the probability of defibrillation success. This could reduce "hands-off" analysis times which diminish the cardiac perfusion and deteriorate the chance for successful defibrillations. METHODS AND RESULTS: Our approach consists in estimating the CPR part of a corrupted signal by adaptive regression on lagged copies of a reference signal which correlate with the CPR artifact signal. The algorithm is based on a state-space model and the corresponding Kalman recursions. It allows for stochastically changing regression coefficients. The residuals of the Kalman estimation can be identified with the CPR-filtered ECG signal. In comparison with ordinary least-squares regression, the proposed algorithm shows, for low signal-to-noise ratio (SNR) corrupted signals, better SNR improvements and yields better estimates of the mean frequency and mean amplitude of the true VF ECG signal. CONCLUSIONS: The preliminary results from a small pool of human VF and animal asystole CPR data are slightly better than the results of comparable previous studies which, however, not only used different algorithms but also different data pools. The algorithm carries the possibility of further optimization.

 


Ievgeniia Kushch, Barbora Arendacká, Svorad Stolc, Pawel Mochalski, Wojciech Filipiak, Konrad Eugen Schwarz, Lukas Schwentner, Alex Schmid, Alexander Dzien, Monika Lechleitner, Viktor Witkovský, Wolfram Miekisch, Jochen K. Schubert, Karl Unterkofler, and Anton Amann. Breath isoprene--aspects of normal physiology related to age, gender and cholesterol profile as determined in a proton transfer reaction mass spectrometry study. Clinical chemistry and laboratory medicine : CCLM / FESCC, 46(7):1011--8, jan 2008. [ DOI | http ]

This study was performed to clarify variations in breath isoprene concentrations with age, gender, body mass index (BMI) and total serum cholesterol. Our cohort consisted of 205 adult volunteers of different smoking background without health complaints. Total cholesterol in blood serum was measured in 79 of these volunteers.

 


A Eisenmann, Anton Amann, M Said, B Datta, Maximilian Ledochowski, W Buchberger, M Said, B Datta, Maximilian Ledochowski, and W Buchberger. Execution and interpretation of hydrogen breath tests . Journal of breath research, 2(4):to appear, 2008. [ DOI | http ]

Hydrogen breath tests are non-invasive and safe diagnostic tools used to investigate functional intestinal disorders. For the diagnosis of fructose or lactose malabsorption as well as for the detection of small intestinal bacterial overgrowth syndrome, hydrogen breath tests are even regarded as gold standard. However, standardization of the testing procedure and the interpretation of the test results are still lacking. In this paper, reliable information on the implementation of the most common hydrogen breath tests and precise guidelines for the interpretation of the test results are presented.

 


Raed A Dweik and Anton Amann. Exhaled breath analysis: the new frontier in medical testing. Journal of Breath Research, 2(3):3, 2008. [ DOI | http ]

With each breath we exhale, thousands of molecules are expelled in ournbreath and each one of us has a 'breathprint' that can tell a lotnabout his or her state of health. While this may be news to some, itnshould not be to people in medicine. For one can argue that the fieldnof breath analysis is as old as the field of medicine itself.nHippocrates described fetor oris and fetor hepaticus in his treatisenon breath aroma and disease, Lavoisier and Laplace in 1784 showed thatnrespiration consumes oxygen and eliminates carbon dioxide [1],nNebelthau in the mid 1800s showed that diabetics emit breath acetonen[2], and Anstie in 1874 isolated ethanol from breath (which is thenbasis of breath alcohol testing today) [3]. The end of the 20thncentury and the beginning of the 21st century, however, have arguablynwitnessed a revolution in our understanding of the constituents ofnexhaled breath and the development of the field of breath analysis andntesting. A major breakthrough in the scientific study of breathnstarted in the 1970s when Linus Pauling demonstrated that there isnmore to exhaled breath than the classic gases of nitrogen, oxygen,ncarbon dioxide and water vapor, a lot more. Based on gas-liquidnpartition chromatography analysis, Linus Pauling reported the presencenof 250 substances in exhaled breath [4]. With modern mass spectrometryn(MS) and gas chromatography mass spectrometry (GC-MS) instruments, wencan now identify more than 1000 unique substances in exhaled breath.nThese substances include elemental gases like nitric oxide and carbonnmonoxide and a multitude of volatile organic compounds. Exhaled breathnalso carries aerosolized droplets collected as 'exhaled breathncondensate' that have non-volatile compounds like proteins dissolvednin them as well. We now have the technology to test for any and all ofnthese components. Thanks to major breakthroughs in new technologiesn(infrared, electrochemical, chemiluminescence, and others) and thenavailability of very sensitive mass spectrometers, the field of breathnanalysis has made considerable advances in the 21st century. Severalnmethods are now in clinical use or about ready to enter that arena.nThere are currently commercially available analyzers that can measurenNO levels in exhaled breath to the parts per billion (ppb) range andncarbon monoxide to the parts per million (ppm) range [5]. Sensitivenmass spectrometers can measure volatile compounds on breath down tonthe parts per trillion (ppt) range. Aerosolized droplets in exhalednbreath can be captured by a variety of methods and analyzed for a widenrange of biomarkers from metabolic end products to proteins to anvariety of cytokines and chemokines, and the possibilities continue tonexpand [6]. A major hurdle that faced this field as it transitionsnfrom the laboratory to clinical testing has been the standardizationnof sample collection methods. To advance in this area, there had to bena close collaboration between technical experts who typically have andevice looking for clinical indication, the medical experts who haventhe clinical problem looking for a test/biomarker that can be helpfulnin diagnosis or monitoring, and industry/commercial experts who cannbuild and commercialize the final product. One great example of hownthe collaboration between technical, medical, and commercialnprofessionals has resulted in a clinically useful tool is thenmeasurement of exhaled nitric oxide (NO) in exhaled breath fornmonitoring airway inflammation. The advent of chemiluminescencenanalyzers in the early 1990s allowed the detection of low (ppb) levelsnof NO in exhaled breath [7]. This was quickly followed by thenobservation that patients with asthma had higher than normal levels ofnNO in their exhaled breath that was later linked to eosinophilicnairway inflammation [8, 9]. Standardization of the gas collectionnmethods and measurement techniques allowed the industry to build thennext generation of analyzers suitable for use in the clinical settingn[10, 11]. In 2003 the FDA approved the first desktop NO analyzer fornmonitoring airway inflammation in asthma [5]. The use of exhaled NO innmonitoring asthma is useful for several reasons. It is non-invasive,nit can be performed repeatedly, and it can be used in children andnpatients with severe airflow obstruction where other techniques arendifficult or not possible to perform. Exhaled NO may also be morensensitive than currently available tests in detecting airwayninflammation, which may allow more optimum therapy [12-19]. As breathnanalysis offers a window on lung physiology and disease, exhalednbreath testing is becoming an increasingly important non-invasivendiagnostic method that can be used in the evaluation of health andndisease states in the lung and beyond. A few years ago the newnInternational Association of Breath Research (IABR) was established tonhave a platform for researchers in the field. The association holds annannual meeting and the newly established Journal of Breath Researchn(JBR) is the official publication of the IABR. In November 2007, thenFirst Breath Analysis Summit/3rd annual meeting of IABR was held onnthe Cleveland Clinic Campus in Cleveland, Ohio, USA. The Summitnbrought together industry executives and entrepreneurs with scientistsnand clinicians to discuss key trends, future directions, and upcomingntechnologies in breath analysis and medicine. The major focus of thenSummit was on medical applications. Topics included exhaled nitricnoxide, exhaled breath condensate, electronic nose and sensor arrays,nmass spectrometry and bench-top instrumentation, and cutting edgensensor technologies. Medical applications that were covered includednasthma, COPD, pulmonary hypertension, other respiratory diseases,ngastrointestinal diseases, occupational diseases, critical illness,nand cancer. This special issue of JBR contains peer-reviewed, fullnarticles of work presented at the Summit and represents thenproceedings of this Summit. References [1] Duveen D I and Klickstein HnS 1955 Antoine Laurent Lavoisier's contributions to medicine andnpublic health Bull. Hist. Med. 29 164-79 [2] Hubbard R S 1920nDetermination of acetone in expired air J. Biol. Chem. 43 57-65 [3]nBaldwin A D 1977 Anstie's alcohol limit: Francis Edmund Anstien1833-1874 Am. J. Public Health 67 679-81 [4] Pauling L, Robinson A B,nTeranishi R and Cary P 1971 Quantitative analysis of urine vapor andnbreath by gas-liquid partition chromatography Proc. Natl Acad. Sci.nUSA 68 2374-6 [5] Gill M, Graff G R, Adler A J and Dweik R A 2006nValidation study of fractional exhaled nitric oxide measurements usingna handheld monitoring device J. Asthma 43 731-4 [6] Horvath I et aln2005 Exhaled breath condensate: methodological recommendations andnunresolved questions Eur. Respir. J. 26 523-48 [7] Gustafsson L E,nLeone A M, Persson M G, Wiklund N P and Moncada S 1991 Endogenousnnitric oxide is present in the exhaled air of rabbits, guinea pigs andnhumans Biochem. Biophys. Res. Commun. 181 852-7 [8] Kharitonov S A,nYates D, Robbins R A, Logan-Sinclair R, Shinebourne E A and Barnes P Jn1994 Increased nitric oxide in exhaled air of asthmatic patientsnLancet 343 133-5 [9] Persson M G, Zetterstrom O, Agrenius V, Ihre Enand Gustafsson L E 1994 Single-breath nitric oxide measurements innasthmatic patients and smokers Lancet 343 146-7 [10] American ThoracicnSociety 1999 Recommendations for standardized procedures for thenon-line and off-line measurement of exhaled lower respiratory nitricnoxide and nasal nitric oxide in adults and children--1999. Thisnofficial statement of the American Thoracic Society was adopted by thenATS Board of Directors, July 1999 Am. J. Respir. Crit. Care Med. 160n2104-17 [11] American Thoracic Society 2005 ATS/ERS Recommendationsnfor Standardized Procedures for the Online and Offline Measurement ofnExhaled Lower Respiratory Nitric Oxide and Nasal Nitric Oxide, 2005nAm. J. Respir. Crit. Care Med. 171 912-30 [12] Dweik R A 2001 Thenpromise and reality of nitric oxide in the diagnosis and treatment ofnlung disease Cleve. Clin. J. Med. 68 486, 488, 490, 493 [13] Dweik RnA, Comhair S A, Gaston B, Thunnissen F B, Farver C, Thomassen M J,nKavuru M, Hammel J, Abu-Soud H M and Erzurum S C 2001 NO chemicalnevents in the human airway during the immediate and latenantigen-induced asthmatic response Proc. Natl Acad. Sci. USA 98 2622-7n[14] Guo F H, Comhair S A, Zheng S, Dweik R A, Eissa N T, Thomassen MnJ, Calhoun W and Erzurum S C 2000 Molecular mechanisms of increasednnitric oxide (NO) in asthma: evidence for transcriptional andnpost-translational regulation of NO synthesis J. Immunol. 164 5970-80n[15] Khatri S B, Ozkan M, McCarthy K, Laskowski D, Hammel J, Dweik R Anand Erzurum S C 2001 Alterations in exhaled gas profile duringnallergen-induced asthmatic response Am. J. Respir. Crit. Care Med. 164n1844-8 [16] Khatri S B, Hammel J, Kavuru M S, Erzurum S C and Dweik RnA 2003 Temporal association of nitric oxide levels and airflow innasthma after whole lung allergen challenge J. Appl. Physiol. 95n436-40; discussion 435 [17] Dweik R A 2002 Nitric oxide reactions innthe asthmatic airway Disease Markers in Exhaled Breath: basicnmechanisms and clinical applications (NATO Science Series) ed NnMarczin and M H Yacoub (Amsterdam: IOS Press) pp 159-66 [18] Grob N Mnand Dweik R A 2008 Exhaled nitric oxide in asthma. From diagnosis, tonmonitoring, to screening: are we there yet? Chest 133 837-9 [19] OzkannM and Dweik R A 2001 Nitric oxide and airway reactivity Clin.nPulmonary Med. 8 199-206

 


Tomasz Ligor, Magdalena Ligor, Anton Amann, Clemens Ager, Miriam Bachler, Alexander Dzien, and Boguslaw Buszewski. The analysis of healthy volunteers' exhaled breath by the use of solid-phase microextraction and GC-MS. Journal of Breath Research, 2(4):046006, dec 2008. [ DOI | http ]

We analysed breath and inhaled room air samples from 39 healthy volunteers (28 non-smokers, 8 smokers and 3 ex-smokers) by SPME-GC-MS. Mixed expiratory and indoor air samples were collected in freshly cleaned Tedlar bags. Eighteen millilitres of each sample were transferred into sealed, evacuated glass vials, preconcentrated by solid-phase microextraction (SPME, carboxen/polydimethylsiloxane) and investigated by gas chromatography with mass spectrometric detection (GC-MS). For the unequivocal identification of potential marker compounds, pure calibration mixtures of reference compounds (depending on commercial availability) were prepared to determine the retention time and mass spectra with respect to our analytical setting. Applying the adapted SPME-GC/MS method with limit of detection in the high ppb range (0.05-15.00 ppb), we succeeded in identifying altogether 38 compounds with concentrations in exhaled breath being at least 50% higher than concentration in inhaled air. From these 38 compounds, 31 were identified not only by the spectral library match but also by retention time of standards. A comparison of retention times and spectrum obtained for standards and determined compounds was performed. We found hydrocarbons (isoprene, 2-pentene, 2-methyl-1-pentene, benzene, toluene, p-cymene, limonene, 2,4-dimethylheptane, n-butane), ketones (acetone, hydroxypropanone, methylvinyl ketone), ethers (dimethyl ether, 1,3-dioxolane), esters (ethyl acetate), aldehydes (propanal, hexanal, heptanal, acrolein) and alcohols (ethanol, 2-metoxyethanol, isopropyl alcohol, 2,2,3,3- tetramethylcyclopropanemethanol, 3,4-dimethylcyclohexanol). Proper identification of compounds in different cohorts of patients and volunteers is the base for further investigation of origin, biochemical background and distribution of potential breath biomarkers.

 


Ievgeniia Kushch, Konrad Eugen Schwarz, Lukas Schwentner, Bettina Baumann, Alexander Dzien, Alex Schmid, Karl Unterkofler, Günter Gastl, Patrik Španěl, David M Smith, and Anton Amann. Compounds enhanced in a mass spectrometric profile of smokers' exhaled breath versus non-smokers as determined in a pilot study using PTR-MS. Journal of breath research, 2(2):26002, jun 2008. [ DOI | .pdf ]

A pilot study has been carried out to define typical characteristics of the trace gas compounds in exhaled breath of non-smokers and smokers to assist interpretation of breath analysis data from patients who smoke with respiratory diseases and lung cancer. Exhaled breath was analyzed using proton transfer reaction-mass spectrometry (PTR-MS) for 370 volunteers (81 smokers, 210 non-smokers, 79 ex-smokers). Volatile organic compounds corresponding to product ions at seven mass-to-charge ratios (m/z 28, 42, 69, 79, 93, 97, 123) in the PTR-MS spectra differentiated between smokers and non-smokers. The Youden index (= maximum of sensitivity + specificity - 1, YI) as a measure for differentiation between smokers and non-smokers was YI = 0.43 for ions at the m/z values 28 (tentatively identified as HCN), YI = 0.75 for m/z = 42 (tentatively identified as acetonitrile) and YI = 0.53 for m/z = 79 (tentatively identified as benzene). No statistically significant difference between smokers and non-smokers was observed for the product ions at m/z = 31 and 33 (compounds tentatively identified as formaldehyde and methanol). When interpreting the exhaled breath of lung cancer or COPD patients, who often smoke, compounds appearing at the above-mentioned seven mass-to-charge ratios should be considered with appropriate care to avoid misdiagnosis. Validation studies in larger numbers of patients with more precise delineation of their smoking behavior and using additional analytical techniques such as GC/MS and SIFT-MS should be carried out.

 


2007

Boguslaw Buszewski, Martyna Kesy, Tomasz Ligor, and Anton Amann. Human exhaled air analytics: biomarkers of diseases. Biomedical chromatography : BMC, 21(6):553--566, 2007. [ DOI | http ]

Over the last few years, breath analysis for the routine monitoring of metabolic disorders has attracted a considerable amount of scientific interest, especially since breath sampling is a non-invasive technique, totally painless and agreeable to patients. The investigation of human breath samples with various analytical methods has shown a correlation between the concentration patterns of volatile organic compounds (VOCs) and the occurrence of certain diseases. It has been demonstrated that modern analytical instruments allow the determination of many compounds found in human breath both in normal and anomalous concentrations. The composition of exhaled breath in patients with, for example, lung cancer, inflammatory lung disease, hepatic or renal dysfunction and diabetes contains valuable information. Furthermore, the detection and quantification of oxidative stress, and its monitoring during surgery based on composition of exhaled breath, have made considerable progress. This paper gives an overview of the analytical techniques used for sample collection, preconcentration and analysis of human breath composition. The diagnostic potential of different disease-marking substances in human breath for a selection of diseases and the clinical applications of breath analysis are discussed.

 


Boguslaw Buszewski, Tomasz Ligor, Wojciech Filipiak, Maria Teresa Vasconcelos, Matevž Pompe, and Marjan Veber. Study of sorptive properties of trap systems for selective enrichment of volatile organic compounds from tobacco smoke samples. Toxicological & Environmental Chemistry, 90(1):51--64, 2007. [ DOI | http ]

Currently for compound detection the most difficult are sampling steps and sample preparation for analysis of highly volatile compounds (VOC) and their derivatives, such as ethylene, propylene, acetaldehyde and acetone. For this purpose single- and multibed sorbent tubes were prepared, filled with the following materials: Tenax TA, Carbotrap, Carbopack C, Carbosieve SIII, Carboxen 569. The linear relationship between the mass of analysed compounds and decreased recovery from carbon molecular sieve was determined. The highest desorption recovery (?100%) for C2?C5 hydrocarbons from multibed sorption traps contained Tenax TA/Carbotrap/Carbosieve SIII. Sorbent traps were also used to determine selected VOC (acetone, acetaldehyde, 2-butanone, benzene, toluene, m,p-xylene) in gas phase of tobacco smoke from single 1R5F reference cigarette. Quantitative analysis of selected compounds was done by standard addition method with r 2 = 0.9931 for 2-butanone and 0.9773 for acetaldehyde. The best combination of sorbent materials included Tenax TA/Carbotrap/Carboxen 569 allowing for VOC determination at low level: 0.31 µg L?1 for m,p-xylene and 40.24 µg L?1 for acetaldehyde. This composition of multibed sorption trap also gave the highest recovery for acetone and 2-butanone as well as the lowest RSD (9.81%, and 9.14%, respectively).

 


Anton Amann, Patrik Španěl, and David M Smith. Breath Analysis: The Approach Towards Clinical Applications. Mini Reviews in Medicinal Chemistry, 7(2):115--129, feb 2007. [ DOI | http ]

Exhaled breath analysis for clinical diagnosis and therapeutic monitoring is described with special reference to the techniques used and the underlying chemistry and physics involved. Brief outlines are given of the research carried out to date, and prospects for the future of this potentially valuable non-invasive technique are indicated.

 


Boguslaw Buszewski, Tomasz Ligor, Wojciech Filipiak, Maria Teresa Vasconcelos, Matevž Pompe, and Marjan Veber. Studing of sorptive properties of systems for selective VOCs enrichment form air sample. Toxicological and Environmental Chemistry, 1:51--64, 2007.


A Wehinger, Alex Schmid, Sergei Mechtcheriakov, Maximilian Ledochowski, C Grabmer, Günter Gastl, and Anton Amann. Lung cancer detection by proton transfer reaction mass-spectrometric analysis of human breath gas. International Journal of Mass Spectrometry, 265(1):49--59, 2007. [ DOI | http ]

Background: Determination of the diagnostic usefulness of proton transfer reaction mass spectrometry (PTR-MS) for detecting primary lung cancer through analysis of volatile organic compounds (VOCs) in exhaled human breath was demonstrated in this investigation. Unlike, for example, gas-chromatographic analyses, PTR-MS can be used without time-consuming preconcentration of the gas samples. Methods: By means of PTR-MS, exhaled breath samples from primary lung cancer patients (n = 17) were analyzed and compared with both an overall control collective (controls total, n = 170) and three sub-collectives: hospital personnel (controls hospital, n = 35), age-matched persons (controls age, n = 25), and smokers (controls s, n = 60), respectively. Results: Among the VOCs present at reasonably high concentrations, the ones leading to the product ion at m/z = 31 (VOC-31, tentatively protonated formaldehyde) and m/z = 43 (VOC-43, tentatively a fragment of protonated iso-propanol), were found at significantly higher concentrations in the breath gas of the primary lung cancer patients as compared to the healthy controls at the following median concentrations (with interquartile distance, iqr): For VOC-31 the median concentrations were 7.0 ppb (iqr, 15.5 ppb) versus 3.0 ppb (iqr, 1.9 ppb) with p 10(-4). For VOC-43 the median concentrations were 244.1 ppb (iqr, 236.2 ppb) versus 94.1 ppb (iqr, 55.2 ppb) with P 10(-6). The discriminative power between the two collectives was further assessed by ROC-curves obtained upon variation of the chosen threshold concentration and by Fisher's Quadratic Discriminant Method. Conclusions: Within the limits of pilot study, VOC-31 and -43 were found to best discriminate between exhaled breath of primary lung cancer cases and healthy controls. Simple and time-saving breath gas analysis by PTR-MS makes this method attractive for a larger clinical evaluation. It may become a new valuable tool for diagnosing primary lung cancer. (c) 2007 Elsevier B.V. All rights reserved.

 


Ž Krkošová, R Kubinec, L Soják, and Anton Amann. Temperature – programmed GC linear retention indices of all C4 – C30 monomethylalkanes on methylsilicone OV – 1 stationary phase. A contribution towards a better understanding of volatile organic compounds in exhaled breath. J Chromatography A, 1179:59--68, 2007.


Veronika Ruzsanyi, S Sielemann, and Jörg Ingo Baumbach. Detection of sulfur-free odorants in natural gas using ion mobility spectrometry. Journal of environmental monitoring : JEM, 9(1):61--5, 2007. [ DOI | http ]

Beside the primary motivation of the public gas suppliers for odorizing natural gas with a sulfur-free odorant, which relates to the image of the environment-friendly fuel, natural gas, competing with low-sulfur heating fuel and diesel, a question of crucial importance of how to detect such sulfur-free odorants comes up. Concerning the replacement of sulfur-containing by sulfur-free odorization, the availability of a fast and sensitive detection method that can, further, be used on-site plays a key role. The minimum concentration of the new sulfur-free odorant Gasodor S-Free (S-Free) in natural gas should be added at a level of at least 8.8 mg m(-3) to assure a significant warning smell. Therefore, a dynamic range between 0 and approx. 25 mg m(-3) must be realised in the rather complex matrix of natural gas. By means of a handheld ion mobility spectrometer, the odorant content in natural gas is determined within less than 80 s total analysis time directly at the gas pipe. The concentration of S-Free is monitored between 4 and 23 mg m(-3) respecting the quality of the natural gas (high- and low-caloric gas). Results of the validation using a gas chromatograph as a reference standard will be discussed in detail.

 


2006

Wolfgang Lederer, Christoph J. Schlimp, Thomas Niederklapfer, and Anton Amann. Altered electrical activity of fibrillation process following thrombolytic therapy in out-of-hospital cardiac arrest patients with sustained ventricular fibrillationfile:///D:/TEMP/lederer2006.pdf. Med Hypotheses, 67(2):333--335, 2006. [ DOI | http ]

The likelihood of successful defibrillation in patients with sustained ventricular fibrillation (VF) is increased after administering thrombolytics during cardiopulmonary resuscitation (CPR). While dissolution of coronary artery thrombosis resolves the underlying cause of myocardial infarction in the majority of patients, improved microcirculatory reperfusion and alteration of the electrical activity of the fibrillation process may increase the likelihood of restoring spontaneous circulation in cardiac arrest patients. Electrocardiography is a sensitive means of displaying current myocardial perfusion in VF using changes in the frequency and amplitude of fibrillation. Our hypothesis postulates that thrombolytic therapy during CPR increases fibrillation frequency, fibrillation amplitude and amplitude spectrum area, thus improving ventricular fibrillation status and the chance of successful defibrillation.

 


2005

Jörg Ingo Baumbach, W. VAUTZ, Veronika Ruzsanyi, and L Freitag. METABOLITES IN HUMAN BREATH: ION MOBILITY SPECTROMETERS AS DIAGNOSTIC TOOLS FOR LUNG DISEASES. In Anton Amann and David Smith, editors, Breath Analysis for Clinical Diagnosis and Therapeutic Monitoring, pages 53--66. WORLD SCIENTIFIC, may 2005. [ DOI | http ]


Maximilian Ledochowski, Anton Amann, and Dietmar Fuchs. Breath Gas Analysis in Patients with Malabsorption Syndromes. In A Amann and D Smith, editors, Breath Gas Analysis for Medical Diagnostics. World Scientific, Singapore, 2005.


U Janovsky, Sabine Scholl-Bürgi, D Karall, Jonathan Beauchamp, Armin Hansel, Guy Poupart, Alex Schmid, and Anton Amann. Breath gas analysis in patients suffering from propionic acidaemia. In A Amann and D Smith, editors, Breath Analysis for Clinical Diagnosis and Therapeutic Monitoring, pages 401--407. World Scientific, Singapore, 2005.


Veronika Ruzsanyi, Jörg Ingo Baumbach, S Sielemann, P Litterst, M Westhoff, and L Freitag. Detection of human metabolites using multi-capillary columns coupled to ion mobility spectrometers. Journal of Chromatography A, 1084(1-2):145--151, 2005. [ DOI | http ]

The human breath contains indicators of human health and delivers information about different metabolism processes of the body. The detection and attribution of these markers provide the possibility for new, non-invasive diagnostic methods. In the recent study, ion mobility spectrometers are used to detect different volatile organic metabolites in human breath directly. By coupling multi-capillary columns using ion mobility spectrometers detection limits down to the ng/L and pg/L range are achieved. The sampling procedure of human breath as well as the detection of different volatiles in human breath are described in detail. Reduced mobilities and detection limits for different analytes occurring in human breath are reported. In addition, spectra of exhaled air using ion mobility spectrometers obtained without any pre-concentration are presented and discussed in detail. Finally, the potential use of IMS with respect to lung infection diseases will be considered. (c) 2005 Elsevier B.V. All rights reserved.

 


Anton Amann, Stefan Telser, L Hofer, Alex Schmid, and Hartmann Hinterhuber. Exhaled breath as a biochemical probe during sleep. In A Amann and D Smith, editors, Breath Analysis for Clinical Diagnosis and Therapeutic Monitoring, pages 305--316. World Scientific, Singapore, 2005.


Anton Amann, Stefan Telser, L Hofer, Alex Schmid, and Hartmann Hinterhuber. Breath gas as a biochemical probe in sleeping individuals. In A Amann and D Smith, editors, Breath Analysis for Clinical Diagnosis and Therapeutic Monitoring, pages 305--316. World Scientific, Singapore, 2005.


2004

Anton Amann, Guy Poupart, Stefan Telser, Maximilian Ledochowski, Alex Schmid, and Sergei Mechtcheriakov. Applications of breath gas analysis in medicine. International Journal of Mass Spectrometry, 239(2-3):227--233, 2004. [ DOI | http ]

Volatile organic compounds (VOCs) in exhaled breath gas provide valuable information about the subjects' physiological and pathophysiological condition. Proton-transfer-reaction mass spectrometry (PTR-MS) allows rapid and online measurements of these substances. We present results of three studies illustrating the potential of breath gas analysis by PTR-MS in various contexts: long-time online monitoring of VOCs in sleeping subjects suggests that VOC profiles are related to sleep stages. Analysis of VOC concentrations in the breath of carbohydrate malabsorbers emphasizes the role played by bacteria in the gut. Finally, we demonstrate the large intra- and intersubject concentration variability of VOCs by considering one particular mass. 2004 Elsevier B.V. All rights reserved.

 


Marco Freek, Jörg Ingo Baumbach, Augustine Choi, Raed A Dweik, Lars Gustafsson, Armin Hansel, Innsbruck Maximilian, and Andrew B Lindstrom. Breath Gas Analysis For Medical Diagnostics. In Breath Gas Analysis for Medical Diagnostics, Dornbirn, 2004.


2003

G R Harrison, A D Critchley, Chris A. Mayhew, and J M Thompson. Real-time breath monitoring of propofol and its volatile metabolites during surgery using a novel mass spectrometric technique: a feasibility study. Br J Anaesth, 91(6):797--799, 2003. [ .pdf ]

BACKGROUND: At present, there is no rapid method for determining the plasma concentration of i.v. anaesthetics. A solution might be the measurement of the anaesthetic concentration in expired breath and its relation to the plasma concentration. We used chemical ionization methods to determine whether an i.v. anaesthetic can be detected in the low concentrations (parts per billion by volume) in the expired breath of an anaesthetized patient. METHOD: Chemical ionization mass spectrometry can measure trace gases in air with high sensitivity without interference from major gases. We carried out a feasibility trial with a proton transfer reaction mass spectrometer (PTR-MS) to monitor the i.v. anaesthetic agent propofol and two of its metabolites in exhaled gas from an anaesthetic circuit. Exhaled gas was sampled via a 4 m long, unheated tube connected to the PTR-MS. RESULTS: Propofol and its metabolites were monitored in real time in the expired breath of patients undergoing surgery. CONCLUSION: Routine measurement of i.v. agents, analogous to that for volatile anaesthetic agents, may be possible.

 


2002

Veronika Ruzsanyi, S Sielemann, and Jörg Ingo Baumbach. Determination of VOCs in human breath using IMS. Int J Ion Mobility Spectrometry, 5:45--48, 2002.


2001

J Rieder, P Lirk, C Ebenbichler, G Gruber, P Prazeller, Werner Lindinger, and Anton Amann. Analysis of volatile organic compounds: possible applications in metabolic disorders and cancer screening. Wien Klin Wochenschr, 113(5-6):181--185, 2001. [ http ]

The human breath contains a variety of endogenous volatile organic compounds (VOCs). The origin and pathophysiological importance of these VOCs is poorly investigated. Little is known about the interaction of VOCs from ambient air, such as those produced by plants and exhaust fumes, with the human organism. Gas chromatographic determination of VOC concentrations is tedious. Proton-transfer-mass spectroscopy (PTR-MS), a new technology for the online detection of VOC patterns, is a valuable alternative. We present two interesting molecular species, isoprene and ortho (o)-toluidine, as examples of endogenously produced VOCs. In a case study, breath isoprene reductions during lipid-lowering therapy (36%) were shown to correlate with cholesterol (32%) and LDL concentrations (35%) in blood (p 0.001) over a period of 15 days. Therefore, isoprene concentrations in human breath (measured by PTR-MS) might serve as an additional parameter to complement invasive tests for controlling lipid-lowering therapy. Furthermore, it may be a useful parameter for lipid disorder screening. Mass-108, which presumably represents o-toluidine in our breath samples, was found in significantly higher concentrations in the breath of patients with different tumors (1.5 +/- 0.8 ppbv) than in age-matched controls (0.24 +/- 0.1 ppbv, p 0.001). Inflammatory reactions do not seem to alter the pattern of mass-108. Therefore, it appears to be a currently underestimated carcinoma marker that deserves further investigation.

 


J Rieder, P Prazeller, M Boehler, P Lirk, Werner Lindinger, and Anton Amann. Online monitoring of air quality at the postanesthetic care unit by proton-transfer-reaction mass spectrometry. Anesth Analg, 92(2):389--392, 2001. [ .pdf ]

The subthreshold exposure to trace anesthetic gases is not associated with considerable risk of adverse health effects. Online control of ambient air exchange at the postoperative workplace may help in supervising air quality and lead to cost reduction. A proton-transfer-reaction mass spectrometer system was used for online monitoring of volatile organic compounds, especially anesthetic gases. The mean exposure to sevoflurane and isoflurane at the urological postanesthesia care unit (PACU) was 15.9 and 9.5 parts per billion, respectively. Sevoflurane and isoflurane concentrations at the urological PACU showed a patient turnover-dependent burden during our investigation period. Because modern PACUs have a high ventilation capacity, the 24-h occupational burden by anesthetic gases at the PACU is relatively low. Monitoring and controlling of ambient air by automatic built-in alarm systems would be useful for quality control of the postoperative workplace. Moreover, energy costs of ventilation systems could be reduced by coupling ventilation capacity to the effective exposure.