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BackgroundHuman breath contains volatile organic compounds (VOCs) that are biomarkers of breast cancer. We investigated the positive and negative predictive values (PPV and NPV) of breath VOC biomarkers as indicators of breast cancer risk.MethodsWe employed ultra-clean breath collection balloons to collect breath samples from 54 women with biopsy-proven breast cancer and 124 cancer-free controls. Breath VOCs were analyzed with gas chromatography (GC) combined with either mass spectrometry (GC MS) or surface acoustic wave detection (GC SAW). Chromatograms were randomly assigned to a training set or a validation set. Monte Carlo analysis identified significant breath VOC biomarkers of breast cancer in the training set, and these biomarkers were incorporated into a multivariate algorithm to predict disease in the validation set. In the unsplit dataset, the predictive algorithms generated discriminant function (DF) values that varied with sensitivity, specificity, PPV and NPV.ResultsUsing GC MS, test accuracy = 90% (area under curve of receiver operating characteristic in unsplit dataset) and cross-validated accuracy = 77%. Using GC SAW, test accuracy = 86% and cross-validated accuracy = 74%. With both assays, a low DF value was associated with a low risk of breast cancer (NPV > 99.9%). A high DF value was associated with a high risk of breast cancer and PPV rising to 100%.ConclusionAnalysis of breath VOC samples collected with ultra-clean balloons detected biomarkers that accurately predicted risk of breast cancer.

In mammals, especially rodents, social behaviours, such as parenting, territoriality or mate attraction, are largely based on olfactory communication through chemosignals. These behaviours are mediated by species-specific chemosignals, including small organic molecules and proteins that are secreted in the urine or in various fluids from exocrine glands. Chemosignal detection is mainly ensured by olfactory neurons in two specific sensory organs, the vomeronasal organ (VNO) and the main olfactory epithelium (MOE). This study aimed to characterise the olfactory communication in the fossorial ecotype of the water voles, Arvicola terrestris. We first measured the olfactory investigation of urine and lateral scent gland secretions from conspecifics. Our results showed that water voles can discriminate the sex of conspecifics based on the smell of urine, and that urinary male odour is attractive for female voles. Then, we demonstrated the ability of the VNO and MOE to detect volatile organic compounds (VOCs) found in water vole secretions using live-cell calcium imaging in dissociated cells. Finally, we evaluated the attractiveness of two mixtures of VOCs from urine or lateral scent glands in the field during a cyclical outbreak of vole populations.

Background The increasing antimicrobial resistance caused by the improper use of antibiotics poses a significant challenge to humanity. Rapid and accurate identification of microbial species in clinical settings is crucial for precise medication and reducing the development of antimicrobial resistance. This study aimed to explore a method for automatic identification of bacteria using Volatile Organic Compounds (VOCs) analysis and deep learning algorithms. Results AlexNet, where augmentation is applied, produces the best results. The average accuracy rate for single bacterial culture classification reached 99.24% using cross-validation, and the accuracy rates for identifying the three bacteria in randomly mixed cultures were SA:98.6%, EC:98.58% and PA:98.99%, respectively. Conclusion This work provides a new approach to quickly identify bacterial microorganisms. Using this method can automatically identify bacteria in GC-IMS detection results, helping clinical doctors quickly detect bacterial species, accurately prescribe medication, thereby controlling epidemics, and minimizing the negative impact of bacterial resistance on society.

Early diagnosis of lung cancer (LC) can significantly reduce its mortality rate. Considering the limitations of the high false positive rate and reliance on radiologists’ experience in computed tomography (CT)–based diagnosis, a multi-modal early LC screening model that combines radiology with other non-invasive, rapid detection methods is warranted. A high-resolution, multi-modal, and low-differentiation LC screening strategy named ensemble text and breath analysis (ETBA) is proposed that ensembles radiology report text analysis and breath analysis. In total, 231 samples (140 LC patients and 91 benign lesions [BL] patients) were screened using proton transfer reaction–time of flight–mass spectrometry and CT screening. Participants were randomly assigned to a training set and a validation set (4:1) with stratification. The report section of the radiology reports was used to train a text analysis (TA) model with a natural language processing algorithm. Twenty-two volatile organic compounds (VOCs) in the exhaled breath and the prediction results of the TA model were used as predictors to develop the ETBA model using an extreme gradient boosting algorithm. A breath analysis model was developed based on the 22 VOCs. The BA and TA models were compared with the ETBA model. The ETBA model achieved a sensitivity of 94.3%, a specificity of 77.3%, and an accuracy of 87.7% with the validation set. The radiologist diagnosis performance with the validation set had a sensitivity of 74.3%, a specificity of 59.1%, and an accuracy of 68.1%. High sensitivity and specificity were obtained by the ETBA model compared with radiologist diagnosis. The ETBA model has the potential to provide sensitivity and specificity in CT screening of LC. This approach is rapid, non-invasive, multi-dimensional, and accurate for LC and BL diagnosis.

BackgroundEarly diagnosis of necrotising enterocolitis (NEC) may improve prognosis but there are no proven biomarkers.ObjectiveTo investigate changes in faecal volatile organic compounds (VOCs) as potential biomarkers for NEC.DesignMulticentre prospective study.Settings8 UK neonatal units.PatientsPreterm infants <34 weeks gestation.MethodsDaily faecal samples were collected prospectively from 1326 babies of whom 49 subsequently developed definite NEC. Faecal samples from 32 NEC cases were compared with samples from frequency-matched controls without NEC. Headspace, solid phase microextraction gas chromatography/mass spectrometry was performed and VOCs identified from reference libraries. VOC samples from cases and controls were compared using both discriminant and factor analysis methods.ResultsVOCs were found to cluster into nine groups (factors), three were associated with NEC and indicated the possibility of disease up to 3–4 days before the clinical diagnosis was established. For one factor, a 1 SD increase increased the odds of developing NEC by 1.6 times; a similar decrease of the two other factors was associated with a reduced risk (OR 0.5 or 0.7, respectively). Discriminant analyses identified five individual VOCs, which are associated with NEC in babies at risk, each with an area under the receiver operating characteristics curve of 0.75–0.76, up to 4 days before the clinical diagnosis was made.ConclusionsFaecal VOCs are altered in preterm infants with NEC. These data are currently insufficient to enable reliable cotside detection of babies at risk of developing NEC and further work is needed investigate the role of VOCs in clarifying the aetiology of NEC.

Abstract Introduction Cannabis and tobacco couse is common and could expose users to higher levels of toxicants. No studies have examined biomarkers of toxicant exposure in cousers of cannabis and cigarettes, compared with cigarette smokers (CS). Aims and Methods Adult daily CS were recruited from 10 US sites for a study of reduced nicotine cigarettes. In this analysis of baseline data, participants were categorized as either cousers of cannabis and tobacco (cousers; N = 167; urine positive for 11-nor-9-carboxy-Δ 9-tetrahydrocannnabinol and self-reported cannabis use ≥1×/week), or CS (N = 911; negative urine and no self-reported cannabis use). Participants who did not meet either definition (N = 172) were excluded. Self-reported tobacco and cannabis use and tobacco and/or combustion-related biomarkers of exposure were compared between groups. Results Compared to CS, cousers were younger (couser Mage = 38.96, SD = 13.01; CS Mage = 47.22, SD = 12.72; p < .001) and more likely to be male (cousers = 67.7%, CS = 51.9%, p < .001). There were no group differences in self-reported cigarettes/day, total nicotine equivalents, or breath carbon monoxide, but cousers had greater use of non-cigarette tobacco products. Compared to CS, cousers had higher concentrations of 3-hydroxypropylmercapturic acid, 2-cyanoethylmercapturic acid, S-phenylmercapturic acid, 3-hydroxy-1-methylpropylmercapturic acid (ps < .05), and phenanthrene tetraol (p < .001). No biomarkers were affected by number of cannabis use days/week or days since last cannabis use during baseline (ps > .05). Conclusions Cousers had higher concentrations of biomarkers of exposure than CS, but similar number of cigarettes per day and nicotine exposure. Additional studies are needed to determine whether cannabis and/or alternative tobacco products are driving the increased toxicant exposure. Implications Cousers of cannabis and tobacco appear to be exposed to greater levels of harmful chemicals (ie, volatile organic compounds and polycyclic aromatic hydrocarbons), but similar levels of nicotine as CS. It is unclear if the higher levels of toxicant exposure in cousers are due to cannabis use or the increased use of alternative tobacco products compared with CS. It is important for studies examining biomarkers of exposure among CS to account for cannabis use as it may have a significant impact on outcomes. Additionally, further research is needed examining exposure to harmful chemicals among cannabis users.

Worldwide, health care professionals working in operating rooms (ORs) are exposed to electrocautery smoke on a daily basis. Aims of this study were to determine composition and concentrations of electrocautery smoke in the OR using mass spectrometry. Prospective observational study at a tertiary care academic center, involving 122 surgical procedures of which 84 were 1:1 computer randomized to smoke evacuation system (SES) versus no SES use. Irritating, toxic, carcinogenic and mutagenic VOCs were observed in OR air, with some exceeding permissible exposure limits (OSHA/NIOSH). Mean total concentration of harmful compounds was 272.69 ppb (± 189 ppb) with a maximum total concentration of harmful substances of 8991 ppb (at surgeon level, no SES). Maximum total VOC concentrations were 1.6 ± 1.2 ppm (minimally-invasive surgery) and 2.1 ± 1.5 ppm (open surgery), and total maximum VOC concentrations were 1.8 ± 1.3 ppm at the OR table ‘at surgeon level’ and 1.4 ± 1.0 ppm ‘in OR room air’ away from the operating table. Neither difference was statistically significant. In open surgery, SES significantly reduced maximum concentrations of specific VOCs at surgeon level, including aromatics and aldehydes. Our data indicate relevant exposure of health care professionals to volatile organic compounds in the OR. Surgical technique and distance to cautery devices did not significantly reduce exposure. SES reduced exposure to specific harmful VOC’s during open surgery. Trial Registration Number: NCT03924206 (clinicaltrials.gov).

Background: Approximately 20% of patients with irritable bowel syndrome (IBS) link symptoms to food intake; a low-FODMAP diet is effective in managing these symptoms. Aims: To evaluate the effectiveness of the Mediterranean version of the low-FODMAP Diet (MED–LFD) compared to NICE guidelines for IBS and to assess changes in stool volatile compound levels. Methods: 108 patients with Rome IV IBS without constipation were randomized into the MED–LFD or NICE group. Primary endpoints included changes in symptom severity and responder rate (reduction of >50 IBS-SSS points) after intervention and at 6 months. Secondary endpoints assessed quality of life, symptom burden, adequate relief, anxiety/depression levels, and adherence. Volatile compound levels were measured using Gas Chromatography/Mass Spectrometry. Results: At both time points, the MED–LFD group showed a significantly greater improvement in symptom severity (159 ± 80 vs. 253 ± 94 and 168 ± 117 vs. 245 ± 98), responder rates (84.6% vs. 60.8% and 79.1% vs. 52.3%), and adherence (75% vs. 41% and 45% vs. 7%). Similar results were observed for all secondary endpoints, with no serious adverse events reported. The MED–LFD intervention was the strongest independent predictor of being a responder at the first (OR = 6.66; 95%CI = 1.46, 30.4) and second follow-up (OR = 4.85; 95%CI = 1.31, 17.96). Short and branched-chain fatty acids were significantly reduced at both follow-ups. Conclusions: The MED–LFD is superior to NICE recommendations in managing non-constipated IBS symptoms and quality of life. It remains to be proven that reduced volatile compound levels might be an objective marker of response to dietary interventions. ClinicalTrials.gov ID: NCT03997708.

Aging is accompanied with increased frailty and comorbidities, which is potentially associated with microbiome perturbations. Dietary fibers could contribute to healthy aging by beneficially impacting gut microbiota and metabolite profiles. We aimed to compare young adults with elderly and investigate the effect of pectin supplementation on fecal microbiota composition, short chain fatty acids (SCFAs), and exhaled volatile organic compounds (VOCs) while using a randomized, double-blind, placebo-controlled parallel design. Fifty-two young adults and 48 elderly consumed 15 g/day sugar beet pectin or maltodextrin for four weeks. Fecal and exhaled breath samples were collected before and after the intervention period. Fecal samples were used for microbiota profiling by 16S rRNA gene amplicon sequencing, and for analysis of SCFAs by gas chromatography (GC). Breath was used for VOC analysis by GC-tof-MS. Young adults and elderly showed similar fecal SCFA and exhaled VOC profiles. Additionally, fecal microbiota profiles were similar, with five genera significantly different in relative abundance. Pectin supplementation did not significantly alter fecal microbiota, SCFA or exhaled VOC profiles in elderly or young adults. In conclusion, aside from some minor differences in microbial composition, healthy elderly and young adults showed comparable fecal microbiota composition and activity, which were not altered by pectin supplementation.

The clinical diagnosis of dermatophytosis and identification of dermatophytes face challenges due to reliance on culture-based methods. Rapid, cost-effective detection techniques for volatile organic compounds (VOCs) have been developed for other microorganisms, but their application to dermatophytes is limited. This study explores using VOCs as diagnostic markers for dermatophytes. We compared VOC profiles across different dermatophyte taxa using solid-phase microextraction (SPME) and advanced analytical methods: gas chromatography-mass spectrometry (GC–MS) and comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry (GC×GC-TOFMS). We analyzed 47 dermatophyte strains from 15 taxa grown on sheep wool, including clinically significant species. Additionally, we examined phylogenetic relationships among the strains to correlate genetic relatedness with metabolite production. Our results showed that GC×GC-TOFMS offered superior resolution but similar differentiation of VOC profiles compared to GC–MS. VOC spectra allowed reliable distinction of taxonomic units at the species level and below, however, these distinctions showed only a slight correlation with phylogenetic data. We identified pan-dermatophyte and species- or strain-specific VOC profiles, indicating their potential for rapid, non-invasive detection of dermatophyte infections, including epidemic strains. These patterns could enable future taxa-specific identification. Our study highlights the potential of VOCs as tools for dermatophyte taxonomy and diagnosis.