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Papers by Guillermo Quintas

The dataset includes the annotated features from the peak table generated using XCMS software and... more The dataset includes the annotated features from the peak table generated using XCMS software and UPLC-TOFMS data acquired from the analysis of plasma samples from 47 quiescent UC and CD patients (23 fatigued, 24 non-fatigued), for the identification of a metabolic phenotype associated to fatigue (SM_peak_table.csv). It also includes the network of protein-protein and protein-metabolite interactions inferred by PIUMet (SM_output_network.html) using a set of 180 annotated features selected as discriminant between fatigue and non-fatigued by univariate (t-test) or multivariate (PLSDA) analysis. UC: ulcerative colitis CD: Crohn disease PIUMet: L. Pirhaji, P. Milani, M. Leidl, T. Curran, J. Avila-Pacheco, C.B. Clish, F.M. White, A. Saghatelian, E. Fraenkel, Revealing disease-associated pathways by network integration of untargeted metabolomics, Nat. Methods, 13 (2016) 770–776.

Matlab scripts for the simulation and treatment of Raman datasets obtained from tim... more Matlab scripts for the simulation and treatment of Raman datasets obtained from time dependent experiments Using MCR-ALS. - SIMULATED DATA: Simulated data is obtained by adding spectra of artificially generated responses (weighted considering artificially generated time profiles) to an experimental cell spectrum (Initial component) Three Different Scenarios are generated. Spectral and time profiles are obtained from here: - EXPERIMENTAL DATA: DOX dataset obtained from here https://doi.org/10.1002/jbio.201800328 - DATA ANALYSIS INSTRUCTIONS Just run datatreatment.m

European Journal of Cancer, 2020

The Analyst, 2016

A multivariate analysis of data from urine with an electronic voltammetric tongue to detect patie... more A multivariate analysis of data from urine with an electronic voltammetric tongue to detect patients with prostate cancer.

The Analyst, 2014

An multivariate approach based on1H NMR spectra profiles of urine samples to detect patients with... more An multivariate approach based on1H NMR spectra profiles of urine samples to detect patients with prostate cancer.

Journal of Separation Science, 2009

This work exploits the possibilities offered by the recently developed multivariate method named ... more This work exploits the possibilities offered by the recently developed multivariate method named Science-Based Calibration (SBC), for the extraction of &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;analyte-specific&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; chromatograms in on-line gradient reversed phase LC-infrared spectrometry (IR) in the presence of a high spectral and chromatographic overlapping between the analyte of interest, co-eluting sample matrix constituents and the mobile phase components. The SBC method uses an experimentally measured single response spectrum of the analyte of interest and representative noise to calculate an optimum regression vector (b(opt(1))). Then, the b(opt(1)) vector is used to predict the concentration of the analyte of interest in the spectra of the LC-IR sample chromatograms. To evaluate the advantages and pitfalls of the proposed approach, two different situations were analysed on real LC-IR data sets obtained from the injection of a series of standard solutions of four nitrophenols (p-nitrophenol, 3-methyl-4-nitrophenol, 2,4-dinitrophenol and 4-nitrophenol) in a reversed phase system under gradient conditions. In the first situation, the extraction of the &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;analyte-specific&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; chromatogram was carried out without previous knowledge of the spectral features of other interferents present in the sample matrix. In a second situation evaluated, data obtained from the LC injection of a sample blank is available. Results show the potential applicability of this technique in a variety of situations and evidenced that the proposed chemometric approach improves the selectivity and sensitivity of the LC-IR hyphenation.

Analytica Chimica Acta, 2021

Extraction of meaningful biological information from the vast array of data that metabolomics ana... more Extraction of meaningful biological information from the vast array of data that metabolomics analyses generate is a major challenge in the field. A variety of computational and visual tools that help to identify changes in metabolic pathways have been proposed including functional analysis and pathway analysis. Meta-analysis of metabolomic data has emerged as a powerful source of information. In this work, the applicability of the Mantel's test for the correlation of functional results from metabolic pathway analysis is shown using experimental and simulated data sets as evaluation examples. The statistical significance of the correlation coefficient can be assessed by permutation testing requiring practically no computation time. The use of the Mantel's test can assist the critical comparison of different phenotypes, studies, methods, platforms, or data preprocessing strategies, as well as help to identify inconsistencies between metabolomic study outcomes, making this algorithm attractive for data interpretation and meta-analysis on a routine basis.

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Journal of Proteome Research

Inflammatory bowel disease (IBD) is a chronic, relapsing non-infectious inflammatory condition of... more Inflammatory bowel disease (IBD) is a chronic, relapsing non-infectious inflammatory condition of the intestinal tract with two main phenotypes -ulcerative colitis (UC) and Crohn's disease (CD)- and a globally increasing incidence and prevalence. Nearly 80% of the IBD patients with active disease and 50% of those with inactive disease suffer fatigue with significant impairment of their quality of life. Fatigue has been associated with multiple factors in IBD patients but, in most cases, no direct cause can be identified and risk factors in clinically quiescent IBD are contradictory. Furthermore, as the assessment of fatigue is subjective, there is an unmet clinical need for fatigue biomarkers. In this explorative study, we analyzed the plasma lipidomic profile of 47 quiescent UC and CD patients (23 fatigued, 24 non-fatigued) by UPLC-TOFMS. Results showed changes in lipids associated with fatigue and IBD. Significantly decreased levels of phosphatidylcholines, plasmanyls, sphingomyelins, lysophosphatidylcholines, phosphatidylethanolamines, phosphatidylinositols, phosphatidylserines, and eicosanoids were observed in patients with fatigue. Network and metabolic pathway analysis indicated a dysregulation of the arachidonic acid and glycerophospholipid metabolisms, and the sphingolipid pathway. The protein-metabolite interaction network showed interactions between functionally related metabolites and proteins, displaying 40 disease-associated hidden proteins including ABDH4, GLTP, and LCAT.

Food chemistry, Jan 30, 2018

Analysis of proteins in bovine milk is usually tackled by time-consuming analytical approaches in... more Analysis of proteins in bovine milk is usually tackled by time-consuming analytical approaches involving wet-chemical, multi-step sample clean-up procedures. The use of external cavity-quantum cascade laser (EC-QCL) based IR spectroscopy was evaluated as an alternative screening tool for direct and simultaneous quantification of individual proteins (i.e. casein and β-lactoglobulin) and total protein content in commercial bovine milk samples. Mid-IR spectra of protein standard mixtures were used for building partial least squares (PLS) regression models. A sample set comprising different milk types (pasteurized; differently processed extended shelf life, ESL; ultra-high temperature, UHT) was analysed and results were compared to reference methods. Concentration values of the QCL-IR spectroscopy approach obtained within several minutes are in good agreement with reference methods involving multiple sample preparation steps. The potential application as a fast screening method for esti...

Analytica chimica acta, Jan 15, 2017

Oxidative stress derived from perinatal asphyxia appears to be closely linked to neonatal brain d... more Oxidative stress derived from perinatal asphyxia appears to be closely linked to neonatal brain damage and lipid peroxidation biomarkers have shown to provide predictive power of oxidative stress related pathologies in situations of hypoxia and reoxygenation in the newborn. The objective of this work was to develop and validate of a comprehensive liquid chromatography tandem mass spectrometry approach for the quantitative profiling of 28 isoprostanoids in newborn plasma samples covering a broad range of lipid peroxidation product classes. The method was developed taking into account the specific requirements for its use in neonatology (i.e. limited sample volumes, straightforward sample processing and high analytical throughput). The method was validated following stringent FDA guidelines and was then applied to the analysis of 150 plasma samples collected from newborns. Information obtained from the quantitative analysis of isoprostanoids was critically compared to that provided by...

Redox biology, Aug 7, 2017

Hypoxic-ischemic encephalopathy (HIE) secondary to perinatal asphyxia is a leading cause of morta... more Hypoxic-ischemic encephalopathy (HIE) secondary to perinatal asphyxia is a leading cause of mortality and acquired long-term neurologic co-morbidities in the neonate. The most successful intervention for the treatment of moderate to severe HIE is moderate whole body hypothermia initiated within 6h from birth. The objective and prompt identification of infants who are at risk of developing moderate to severe HIE in the critical first hours still remains a challenge. This work proposes a metabolite score calculated based on the relative intensities of three metabolites (choline, 6,8-dihydroxypurine and hypoxanthine) that showed maximum correlation with hypoxia time in a consolidated piglet model for neonatal hypoxia-ischemia. The metabolite score's performance as a biomarker for perinatal hypoxia and its usefulness for clinical grading and decision making have been assessed and compared to the performance of lactate which is currently considered the gold standard. For plasma sampl...

Analytica chimica acta, Jan 22, 2017

The analytical determination of bovine milk proteins is important in food and non-food industrial... more The analytical determination of bovine milk proteins is important in food and non-food industrial applications and yet, rather labour-intensive wet-chemical, low-throughput methods have been employed since decades. This work proposes the use of external cavity-quantum cascade laser (EC-QCL) spectroscopy for the simultaneous quantification of the most abundant bovine milk proteins and the total protein content based on the chemical information contained in mid-infrared (IR) spectral features of the amide I band. Mid-IR spectra of protein standard mixtures were used for building partial least squares (PLS) regression models. Protein concentrations in commercial bovine milk samples were calculated after chemometric compensation of the matrix contribution employing science-based calibration (SBC) without sample pre-processing. The use of EC-QCL spectroscopy together with advanced multivariate data analysis allowed the determination of casein, α-lactalbumin, β-lactoglobulin and total pro...