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Exploring the potential of NTME/GC-MS, in the establishment of urinary volatomic profiles. Lung cancer patients as case study.

ABSTRACT: The growing cancer incidence and mortality worldwide claims for the development of novel diagnostic strategies. In this study we aimed to explore the potential of an innovative methodology, based on a needle trap microextraction (NTME), combined with gas chromatography-mass spectrometry (GC-MS), as new approach to isolate and profile urinary volatile organic metabolites (VOMs) from lung cancer (LC) patients and healthy individuals (CTRL). In this context, different experimental parameters with influence of NTME extraction efficiency including, temperature, equilibration time, headspace volume, ionic strength, pH, effects of sample volume and stirring, were investigated and optimized. For the DVB/CarX/Car1000 needle trap device (NTD), the best results were obtained using 40?mL headspace of a 4-mL acidified (pH?=?2) urine sample with 20% NaCl and an extraction temperature of 50?°C for 40?min of equilibration time. The stability of the isolated VOMs was investigated up to 72?h after extraction. From the VOMs identified, belonging namely to ketones, sulphur and benzene derivatives, 98 presented a frequency of occurrence above 90%. Data were processed by discriminant analysis, retrieving differentiated clusters for LC and CTRL groups. As far we are aware, this is the first study using NTME/GC-MS to establish urinary volatomic profiles. Preliminary results are very promising, as broad and comprehensive volatile profiles were obtained. Moreover, the extended storage stability of the NTD devices opens new opportunities for sampling other matrices in a wide range of applications.

SUBMITTER: Porto-Figueira P

PROVIDER: S-EPMC6117359 | biostudies-literature | 2018 Aug

REPOSITORIES: biostudies-literature

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Exploring the potential of NTME/GC-MS, in the establishment of urinary volatomic profiles. Lung cancer patients as case study.

Porto-Figueira Priscilla P Pereira Jorge J Miekisch Wolfram W Câmara José S JS

Scientific reports 20180830 1

The growing cancer incidence and mortality worldwide claims for the development of novel diagnostic strategies. In this study we aimed to explore the potential of an innovative methodology, based on a needle trap microextraction (NTME), combined with gas chromatography-mass spectrometry (GC-MS), as new approach to isolate and profile urinary volatile organic metabolites (VOMs) from lung cancer (LC) patients and healthy individuals (CTRL). In this context, different experimental parameters with i ...[more]

PMID: 30166567

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Project description:BackgroundBisphenol A (BPA) is typically measured in urine using an indirect method that involves enzymatic deconjugation and extraction. In contrast, the direct method measures free and conjugated BPA concurrently and sums them to estimate urinary BPA concentrations. Statistical comparison of total BPA results using the direct and indirect methods is necessary to accurately interpret biomonitoring data for risk assessments.ObjectivesTo compare urinary BPA concentrations estimated from the indirect and direct methods in duplicate first trimester urine samples collected from 1879 pregnant women from the MIREC Study.MethodsFor the indirect method, we measured urinary BPA concentrations using GC-MS/MS. For the direct method, we summed free and conjugated BPA concentrations measured using LC-MS/MS. We evaluated deviation between the two methods using the Bland-Altman analysis in the total sample and stratified (1) by specific gravity and (2) at the limit of quantification (LOQ).ResultsMedian urinary BPA concentrations for the direct and indirect methods were 0.89 µg BPA equivalents/L and 0.81 µg/L respectively. Concentrations from the direct method were, on average, 8.6% (95% CI: 6.7%, 10.5%) higher than the indirect method in a Bland-Altman analysis. The percent differences between the two methods was 4.0% in urines with specific gravities < 1.02 (n = 1348, 72%) and 20.3% in urine with specific gravity ≥ 1.02. In values below the LOQ (n = 663, 35%), we observed smaller average percent deviation (4.8%) between the two methods but wider limits of agreement.DiscussionResults from this study, based on the largest statistically rigorous comparison of the direct and indirect methods of BPA measurement, contrast previous findings reporting that the indirect method underestimates total BPA exposure. The difference in urinary BPA concentrations we observed with the indirect and direct methods is unlikely to alter the interpretation of health outcome data.

Project description:Presuming the stage of metastatic lung cancer is divided by its location, an intermediate state of ?5 cumulative metastasis is defined as oligometastases (OM) and a widespread state of >5 cumulative metastasis as polymetastases (PM). According to the phenotypes, the different metastatic cancer patients can be treated with different methods: the OM patients can be treated by a metastasis-directed local therapy method, whereas the PM patients are not recommended to take such a treatment. It is also believed that the patients at the initial OM stage may progress to the PM stage. Currently, the OM- and PM-metastatic cancer patients can be identified by traditional imaging methods. However, the current methods are found to be insufficient for the discrimination. It hence is meaningful and important to develop new diagnostic methods for a better prediction to the patients following by selecting a correct metastasis-directed treatment.MicroRNAs (miRNAs) can be used as the genetic probes for the new diagnostic methods. In this study, a bioinformatics strategy was employed to screen the microRNAs as potential diagnostic probes for distinguishing the OM and PM lung metastases patients. The expression profiles of microarray data of GSE38698 were downloaded from Gene Expression Omnibus (http://www.ncbi.nlm.nih.gov/geo/) including the information from 63 patients: 24 PM and 39 OM patients. The microRNA expression patterns of tumor samples were identified for the OM and PM patients who were treated with the high-dose radiotherapy. Followed by analyzing the functional enrichment pathways, an early diagnosis model of OM and PM groups was identified with different expression genes (DEGs). The ratios of PM/OM were calculated by setting a high significance in the expressions of 377 mature miRNAs in the profile [log2?(PM/OM) >1 and P?<?.05]. Through a high combination power [area under the curve (AUC) ? 0.875] with the superior sensitivity and specificity, a panel of 10 miRNAs including 7 upregulation and 3 downregulation expressions were identified as potential probes for discriminating the PM and OM patients from the receiving operation characteristic (ROC). Considering the possible involvements of cancer progress, the interconnected axon guidance, cancer metastasis pathways, proteoglycans, and Mitogen-activated protein kinases signaling pathway and endocytosis were suggested for the subsequent miRNA target analysis. The results may reveal a biological significance that a profile of miRNAs can be used as the potential probes to identify the patients at the OM or PM stages and figure out the metastasis-directed treatment methods for the patients at the different metastasis stages.

Dataset Information

Exploring the potential of NTME/GC-MS, in the establishment of urinary volatomic profiles. Lung cancer patients as case study.

Publications

Exploring the potential of NTME/GC-MS, in the establishment of urinary volatomic profiles. Lung cancer patients as case study.

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