Journal of breath research最新文献

{"title":"Revisiting the rationale of mandatory masking.","authors":"Jonathan D Beauchamp, Chris A Mayhew","doi":"10.1088/1752-7163/acdf12","DOIUrl":"10.1088/1752-7163/acdf12","url":null,"abstract":"<p><p>In this perspective, we review the evidence for the efficacy of face masks to reduce the transmission of respiratory viruses, specifically severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and consider the value of mandating universal mask wearing against the widespread negative impacts that have been associated with such measures. Before the SARS-CoV-2 pandemic, it was considered that there was little to no benefit in healthy people wearing masks as prophylaxis against becoming infected or as unwitting vectors of viral transmission. This accepted policy was hastily reversed early on in the pandemic, when districts and countries throughout the world imposed stringent masking mandates. Now, more than three years since the start of the pandemic, the amassed studies that have investigated the use of masks to reduce transmission of SARS-CoV-2 (or other pathogens) have led to conclusions that are largely inconsistent and contradictory. There is no statistically significant or unambiguous scientific evidence to justify mandatory masking for general, healthy populations with the intention of lessening the viral spread. Even if mask wearing could potentially reduce the transmission of SARS-CoV-2 in individual cases, this needs to be balanced against the physical, psychological and social harms associated with forced mask wearing, not to mention the negative impact of innumerable disposed masks entering our fragile environment. Given the lack of unequivocal scientific proof that masks have any effect on reducing transmission, together with the evident harms to people and the environment through the use of masks, it is our opinion that the mandatory use of face masks in the general population is unjustifiable and must be abandoned in future pandemic countermeasures policies.</p>","PeriodicalId":15306,"journal":{"name":"Journal of breath research","volume":"17 4","pages":""},"PeriodicalIF":3.8,"publicationDate":"2023-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9951099","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of immune responses on breath methane dynamics.","authors":"Daniela Polag,&nbsp;Frank Keppler","doi":"10.1088/1752-7163/ace9f2","DOIUrl":"https://doi.org/10.1088/1752-7163/ace9f2","url":null,"abstract":"<p><p>Methane (CH₄) which can be detected in human breath has long been exclusively associated with anaerobic microbial activity (methanogenesis) in the gastrointestinal tract. However, recent studies challenge this understanding by revealing that CH₄might also be produced endogenously in cells through oxidative-reductive stress reactions. Consequently, variations in breath CH₄levels compared to an individual's baseline level might indicate enhanced oxidative stress levels, and, therefore, monitoring breath CH₄levels might offer great potential for '<i>in vivo</i>' diagnostics such as disease diagnosis, monitoring the efficacy of treatments, or during the application of personalized medicine. To evaluate the effects from immune responses triggered by infections, inflammations, and induced perturbation by vaccination on CH₄dynamics in breath, two subjects were monitored over a period of almost 2 years. Breath CH₄levels were measured by gas chromatography equipped with a flame-ionization detector. Both subjects exhibited significant deviations (positive and negative, respectively) from their normal CH₄breath levels during periods of potential enhanced immune activity. Deviations from the 'healthy state' were indicated by the exceeding of individual CH₄ranges. Moreover, for the first time we could clearly prove CH₄degradation induced through vaccination by measuring stable carbon isotopes of CH₄using gas chromatograph-combustion-isotope ratio mass spectrometry. Hence, breath CH₄concentration and isotopic analyses may be used as a biomarker to evaluate specific immune responses and individual immune states.</p>","PeriodicalId":15306,"journal":{"name":"Journal of breath research","volume":"17 4","pages":""},"PeriodicalIF":3.8,"publicationDate":"2023-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10306979","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Food and lifestyle impact on breath VOCs using portable mass spectrometer-pilot study across European countries.","authors":"Milena Aleksić,&nbsp;Andrea Simeon,&nbsp;Djordje Vujić,&nbsp;Stamatios Giannoukos,&nbsp;Boris Brkic","doi":"10.1088/1752-7163/ace8b1","DOIUrl":"https://doi.org/10.1088/1752-7163/ace8b1","url":null,"abstract":"<p><p>In the modern world, many people are changing old dietary and lifestyle habits to improve the quality of their living-to treat or just prevent possible diseases. The main goal of this pilot study was to assess the food and lifestyle impact on exhaled breath volatile organic compounds (VOCs) in various population groups. It was done by employing a recently validated portable membrane-inlet mass spectrometer-MIMS. Thus, the obtained results would also represent the additional confirmation for the employment of the new instrument in the breath analysis. The pilot study involved 151 participants across Europe, including people with overweight, obesity, type 2 diabetes mellitus, cardiovascular disease, people with poor-quality diet and professional athletes. Exhaled breath acetone, ethanol, isoprene, and n-pentane levels were determined in samples before the meal, and 120 min after the meal. Obtained basal ppb_vvalues were mainly in accordance with previously reported, which confirms that MIMS instrument can be used in the breath analysis. Combining the quantified levels along with the information about the participants' lifestyle habits collected via questionnaire, an assessment of the food and lifestyle impact was obtained. Notable alteration in examined VOC levels upon meal consumption was detected in more than 70% of all participants, with exception for isoprene, which was affected in about half of participants. Lifestyle parameters impact was examined using statistical analysis of variance (ANOVA) on ranks test. Statistically significant differences in basal breath VOC levels were observed among all examined population groups. Also, n-pentane and ethanol levels significantly differed in people of different ages, as well as acetone levels in people with different physical activity habits. These findings are promising for further, more focused research using MIMS technique in breath analysis.</p>","PeriodicalId":15306,"journal":{"name":"Journal of breath research","volume":"17 4","pages":""},"PeriodicalIF":3.8,"publicationDate":"2023-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9924347","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cross-validation of the peppermint benchmarking experiment across three analytical platforms.","authors":"Y Lan Pham,&nbsp;Ruyi Yu,&nbsp;Jonathan D Beauchamp","doi":"10.1088/1752-7163/ace8b2","DOIUrl":"https://doi.org/10.1088/1752-7163/ace8b2","url":null,"abstract":"<p><p>The Peppermint Experiment is a breath analysis benchmarking initiative that seeks to address the lack of inter-comparability of outcomes across independent breath biomarker studies. In this experiment, the washout profiles of volatile terpene constituents of encapsulated peppermint oil (mainly<i>α</i>-pinene,<i>β</i>-pinene, limonene and 1,8-cineole) in exhaled breath are characterized through a series of measurements at defined sampling intervals up to 6 h after ingestion of the capsule. In the present work, the Peppermint Experiment was carried out on a cohort of volunteers (<i>n</i>= 11) that provided breath samples in three sittings on different days (i.e. triplicates per volunteer) for concurrent analysis by three different analytical platforms. These platforms were proton transfer reaction-time-of-flight-mass spectrometry (PTR-TOFMS) interfaced with a buffered end-tidal (BET) breath sampler, gas chromatography-ion mobility spectrometry (GC-IMS) in conjunction with a compatible handheld direct breath sampler, and thermal desorption comprehensive two-dimensional gas chromatography-time-of-flight-mass spectrometry (TD-GC×GC-TOFMS) with a Respiration Collection for<i>in-vitro</i>Analysis (ReCIVA) system for trapping breath volatiles onto adsorbent tubes. Regression analysis yielded mean washout times across the cohort of 448 min (PTR-TOFMS and GC-IMS) and 372 min (TD-GC×GC-TOFMS), which are in good alignment with published benchmark values. Large variations in washout profiles were observed at the individuals level, both between (inter-individual) and within (intra-individual) participants, indicating high variability in the degree of absorption, distribution, metabolism and excretion of volatile terpenes in the body within individuals and across the cohort. The comparably low inter-instrument variability indicates that differences in benchmark values from independent studies reported in the literature are driven by biological variability rather than different performances between sampling methods or analytical platforms.</p>","PeriodicalId":15306,"journal":{"name":"Journal of breath research","volume":"17 4","pages":""},"PeriodicalIF":3.8,"publicationDate":"2023-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9924350","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Lactate in exhaled breath condensate and its correlation to cancer: challenges, promises and a call for data.","authors":"Vera Ruzsanyi,&nbsp;Miklós Péter Kalapos","doi":"10.1088/1752-7163/ace647","DOIUrl":"https://doi.org/10.1088/1752-7163/ace647","url":null,"abstract":"<p><p>Owing to its connection to cancer metabolism, lactate is a compound that has been a focus of interest in field of cancer biochemistry for more than a century. Exhaled breath volatile organic compounds (VOCs) and condensate analyses can identify and monitor volatile and non-VOCs, respectively, present in exhaled breath to gain information about the health state of an individual. This work aims to take into account the possible use of breath lactate measurements in tumor diagnosis and treatment control, to discuss technical barriers to measurement, and to evaluate directions for the future improvement of this technique. The use of exhaled breath condensate (EBC) lactic acid levels in disorders other than cancer is also discussed in brief. Whilst the use of EBC for the detection of lactate in exhaled breath is a promising tool that could be used to monitor and screen for cancer, the reliability and sensitivity of detection are uncertain, and hence its value in clinical practice is still limited. Currently, lactate present in plasma and EBC can only be used as a biomarker for advanced cancer, and therefore it presently has limited differential diagnostic importance and is rather of prognostic value.</p>","PeriodicalId":15306,"journal":{"name":"Journal of breath research","volume":"17 4","pages":""},"PeriodicalIF":3.8,"publicationDate":"2023-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9915080","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Predicting particle deposition using a simplified 8-path in silico human lung prototype.","authors":"Raul Barrio Perotti,&nbsp;Noelia Martín-Fernández,&nbsp;Carmen Vigil-Díaz,&nbsp;Keith Walters,&nbsp;Ana Fernández-Tena","doi":"10.1088/1752-7163/ace6c7","DOIUrl":"10.1088/1752-7163/ace6c7","url":null,"abstract":"<p><p>Understanding particle deposition in the human lung is crucial for the assessment of environmental pollutants and the design of new drug delivery systems. Traditionally, research has been carried out by experimental analysis, but this generally requires expensive equipment and exposure of volunteers to radiation, resulting in limited data. To overcome these drawbacks, there is an emphasis on the development of numerical models capable of accurate predictive analysis. The most advanced of these computer simulations are based on three-dimensional computational fluid dynamics. Solving the flow equations in a complete, fully resolved lung airway model is currently not feasible due to the computational resources required. In the present work, a simplified lung model is presented and validated for accurate prediction of particle deposition. Simulations are performed for an 8-path approximation to a full lung airway model. A novel boundary condition method is used to ensure accurate results in truncated flow branches. Simulations are performed at a steady inhalation flow rate of 18 l min^-1, corresponding to a low activity breathing rate, while the effects of particle size and density are investigated. Comparison of the simulation results with available experimental data shows that reasonably accurate results can be obtained at a small fraction of the cost of a full airway model. The simulations clearly evaluate the effect of both particle size and particle density. Most importantly, the results show an improvement over a previously documented single-path model, both in terms of accuracy and the ability to obtain regional deposition rates. The present model represents an improvement over previously used simplified models, including single-path models. The multi-path reduced airway approach described can be used by researchers for general and patient-specific analyses of particle deposition and for the design of effective drug delivery systems.</p>","PeriodicalId":15306,"journal":{"name":"Journal of breath research","volume":"17 4","pages":""},"PeriodicalIF":3.8,"publicationDate":"2023-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9843505","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Establishing a cell-based screening workflow for determining the efficiency of CYP2C9 metabolism: moving towards the use of breath volatiles in personalised medicine.","authors":"Franziska Lochmann,&nbsp;Aleksandar Nikolajevic,&nbsp;Valentina Stock,&nbsp;Sarah Kammerer,&nbsp;Monica L Fernández-Quintero,&nbsp;Johannes R Loeffler,&nbsp;Klaus R Liedl,&nbsp;Jakob Troppmair,&nbsp;Chris A Mayhew,&nbsp;Veronika Ruzsanyi","doi":"10.1088/1752-7163/ace46f","DOIUrl":"https://doi.org/10.1088/1752-7163/ace46f","url":null,"abstract":"<p><p>The use of volatile biomarkers in exhaled breath as predictors to individual drug response would advance the field of personalised medicine by providing direct information on enzyme activity. This would result in enormous benefits, both for patients and for the healthcare sector. Non-invasive breath tests would also gain a high acceptance by patients. Towards this goal, differences in metabolism resulting from extensive polymorphisms in a major group of drug-metabolizing enzymes, the cytochrome P450 (CYP) family, need to be determined and quantified. CYP2C9 is responsible for metabolising many crucial drugs (e.g., diclofenac) and food ingredients (e.g., limonene). In this paper, we provide a proof-of-concept study that illustrates the<i>in vitro</i>bioconversion of diclofenac in recombinant HEK293T cells overexpressing CYP2C9 to 4'-hydroxydiclofenac. This<i>in vitro</i>approach is a necessary and important first step in the development of breath tests to determine and monitor metabolic processes in the human body. By focusing on the metabolic conversion of diclofenac, we have been able to establish a workflow using a cell-based system for CYP2C9 activity. Furthermore, we illustrate how the bioconversion of diclofenac is limited in the presence of limonene, which is another CYP2C9 metabolising substrate. We show that increasing limonene levels continuously reduce the production of 4'-hydroxydiclofenac. Michaelis-Menten kinetics were performed for the diclofenac 4'-hydroxylation with and without limonene, giving a kinetic constant of the reaction,<i>K</i>_M, of 103<i>µ</i>M and 94.1<i>µ</i>M, respectively, and a maximum reaction rate,<i>V</i>_max, of 46.8 pmol min^-110⁶cells^-1and 56.0 pmol min^-110⁶cells^-1with and without the inhibitor, respectively, suggesting a non-competitive or mixed inhibition type. The half-maximal inhibitory concentration value (IC₅₀) for the inhibition of the formation of 4'-hydroxydiclofenace by limonene is determined to be 1413<i>µ</i>M.</p>","PeriodicalId":15306,"journal":{"name":"Journal of breath research","volume":"17 4","pages":""},"PeriodicalIF":3.8,"publicationDate":"2023-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9843486","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Screening for volatile biomarkers of colorectal cancer by analyzing breath and fecal samples using thermal desorption combined with GC-MS (TD-GC-MS).","authors":"Monika Śmiełowska,&nbsp;Tomasz Ligor,&nbsp;Wojciech Kupczyk,&nbsp;Jacek Szeliga,&nbsp;Marek Jackowski,&nbsp;Boguslaw Buszewski","doi":"10.1088/1752-7163/ace46e","DOIUrl":"https://doi.org/10.1088/1752-7163/ace46e","url":null,"abstract":"<p><p>Breath and fecal VOCs, among others, represent a new and encouraging clinical practice for the differential diagnosis of CRC. The purpose of our research was to identify VOCs present in exhaled air and feces of 20 HVs and 15 CRC patients. For collection of gas phase released from feces, emission microchambers were applied. Sorption tubes were used to enrich analytes for both breath and fecal samples. TD technique combined with GC-MS was used at the separation and identification step. The combination of statistical methods was used to evaluate the ability of VOCs to classify control group and CRC patients. Heptanoic acid, acetone, 2,6,10-trimethyldodecane, n-hexane, skatole, and dimethyl trisulfide are observed in elevated amounts in the patients group. The performance of diagnostic models on the tested data set was above 90%. This study is the first attempt to document the using of TD-GC-MS to analyze both breath and fecal samples to search for volatile biomarkers of CRC. A full evaluation of the results described herein requires further studies involving a larger number of samples. Moreover, it is particularly important to understand the metabolic pathways of substances postulated as tumor biomarkers.</p>","PeriodicalId":15306,"journal":{"name":"Journal of breath research","volume":"17 4","pages":""},"PeriodicalIF":3.8,"publicationDate":"2023-07-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9803663","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Identification of a characteristic VOCs pattern in the exhaled breath of post-COVID subjects: are metabolic alterations induced by the infection still detectable?","authors":"Alessia DI Gilio,&nbsp;Jolanda Palmisani,&nbsp;Arcangelo Picciariello,&nbsp;Carlo Zambonin,&nbsp;Antonella Aresta,&nbsp;Nicoletta De Vietro,&nbsp;Silvana Angela Franchini,&nbsp;Gianrocco Ventrella,&nbsp;Marirosa Nisi,&nbsp;Sabina Licen,&nbsp;Pierluigi Barbieri,&nbsp;Donato Altomare,&nbsp;Gianluigi de Gennaro","doi":"10.1088/1752-7163/ace27c","DOIUrl":"https://doi.org/10.1088/1752-7163/ace27c","url":null,"abstract":"<p><p>SARS-CoV-2 is expected to cause metabolic alterations due to viral replication and the host immune response resulting in increase of cytokine secretion and cytolytic activity. The present prospective observational study is addressed at exploring the potentialities of breath analysis in discrimination between patients with a documented previous history of symptomatic SARS-CoV-2 infection and, at the moment of the enrollment, exhibiting a negative nasopharyngeal swab and acquired immunity (post-COVID) and healthy subjects with no evidence of previous SARS-CoV-2 infection (no-COVID). The main purpose is to understand if traces of metabolic alterations induced during the acute phase of the infection are still detectable after negativization, in the form of a characteristic volatile organic compound (VOC) pattern. An overall number of 60 volunteers aged between 25 and 70 years were enrolled in the study (post-COVID: n.30; no-COVID: n. 30), according to well-determined criteria. Breath and ambient air samples were collected by means of an automated sampling system (Mistral) and analyzed by thermal desorption-gas chromatography-mass spectrometry (TD-GC/MS). Statistical tests (Wilcoxon/Kruskal-Wallis test) and multivariate data analysis (principal component analysis (PCA), linear discriminant analysis) were performed on data sets. Among all compounds detected (76 VOCs in 90% of breath samples), 5 VOCs (1-propanol, isopropanol, 2-(2-butoxyethoxy)ethanol, propanal and 4-(1,1-dimethylpropyl)phenol) showed abundances in breath samples collected from post-COVID subjects significantly different with respect to those collected from no-COVID group (Wilcoxon/Kruskal-Wallis test,<i>p</i>-values <0.05). Although not completely satisfactory separation between the groups was obtained, variables showing significant differences between the two groups and higher loadings for PCA are recognized biomarkers of COVID-19, according to previous studies in literature. Therefore, based on the outcomes obtained, traces of metabolic alterations induced by SARS-CoV-2 infection are still detectable after negativization. This evidence raises questions about the eligibility of post-COVID subjects in observational studies addressed at the detection of COVID-19. (Ethical Committee Registration number: 120/AG/11).</p>","PeriodicalId":15306,"journal":{"name":"Journal of breath research","volume":"17 4","pages":""},"PeriodicalIF":3.8,"publicationDate":"2023-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9796746","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sterilization and reuse of masks for a standardized exhaled breath collection device by autoclaving.","authors":"Samuel T Shawn, Sean W Harshman, Christina N Davidson, Jae Hwan Lee, Anne E Jung, Ariel Parker, M Aaron Hawkins, Blake W Stamps, Rhonda L Pitsch, Jennifer A Martin","doi":"10.1088/1752-7163/ace127","DOIUrl":"10.1088/1752-7163/ace127","url":null,"abstract":"<p><p>Exhaled breath research has been hindered by a lack of standardization in collection and analysis methodologies. Recently, the Respiration Collector for<i>In Vitro</i>Analysis (ReCIVA) sampling device has illustrated the potential to provide a consistent and convenient method for exhaled breath collection onto adsorbent media. However, the significant costs, compared to exhaled breath bags, associated with the standardized collector is believed to be the reason for limited widespread use by researchers in the exhaled breath field. For example, in addition to the sampling hardware, a single-use disposable silicon mask affixed with a filter is required for each exhaled breath collection. To reduce the financial burden, streamline device upkeep, reduce waste material, and ease the logistical burden associated with the single use masks, it is hypothesized that the consumable masks and filters could be sterilized by autoclaving for reuse. The masks were contaminated, autoclaved, and then tested for any surviving pathogens with spore strip standards and by measuring the optical density of cultures. The compound background collected when using the ReCIVA with new masks was compared to that collected with repeatedly autoclaved masks via thermal desorption gas chromatography mass spectrometry (TD-GC-MS). The capacity to block particulate matter of new filters was tested against that of autoclaved filters by introducing an aerosol and comparing pre-filter and post-filter particle counts. Finally, breath samplings were conducted with new masks and autoclaved masks to test for changes in measurements by TD-GC-MS of exogenous and endogenous compounds. The data illustrate the autoclave cycle sterilizes masks spiked with saliva to background levels (<i>p</i>= 0.2527). The results indicate that background levels of siloxane compounds are increased as masks are repetitively autoclaved. The data show that mask filters have significant breakthrough of 1<i>μ</i>m particles after five repetitive autoclaving cycles compared to new filters (<i>p</i>= 0.0219). Finally, exhaled breath results utilizing a peppermint ingestion protocol indicate two compounds associated with peppermint, menthone and 1-Methyl-4-(1-methylethyl)-cyclohexanol, and an endogenous exhaled breath compound, isoprene, show no significant difference if sampled with a new mask or a mask autoclaved five times (<i>p</i>> 0.1063). Collectively, the data indicate that ReCIVA masks and filters can be sterilized via autoclave and reused. The results suggest ReCIVA mask and filter reuse should be limited to three times to limit potentially problematic background contaminants and filter dysfunction.</p>","PeriodicalId":15306,"journal":{"name":"Journal of breath research","volume":"17 3","pages":""},"PeriodicalIF":3.8,"publicationDate":"2023-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9734821","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}