0000000001156354
AUTHOR
Julia Kuligowski
showing 52 related works from this author
Evaluation of the effect of chance correlations on variable selection using Partial Least Squares -Discriminant Analysis
2013
Variable subset selection is often mandatory in high throughput metabolomics and proteomics. However, depending on the variable to sample ratio there is a significant susceptibility of variable selection towards chance correlations. The evaluation of the predictive capabilities of PLSDA models estimated by cross-validation after feature selection provides overly optimistic results if the selection is performed on the entire set and no external validation set is available. In this work, a simulation of the statistical null hypothesis is proposed to test whether the discrimination capability of a PLSDA model after variable selection estimated by cross-validation is statistically higher than t…
Atmospheric compensation in Fourier transform infrared (FT-IR) spectra of clinical samples.
2013
A new method is proposed for the elimination of the spectral contribution of two atmospheric gases (CO2 and H2O) in Fourier transform infrared (FT-IR) spectra of clinical samples. The algorithm is based on the measurement of reference spectra of H2O followed by an automatic calculation of the spectral contribution of the above-mentioned gases to the sample spectra. Then this contribution is compensated by spectral subtraction. Attenuated total reflectance FT-IR spectra of serum and urine samples in the presence of atmospheric gases were corrected and compared with spectra obtained with an N2 purge. Visual inspection of the spectra as well as calculated noise levels confirmed that the metho…
An infrared spectroscopic tool for process monitoring: sugar contents during the production of a depilatory formulation.
2012
Abstract A fast, reliable and economical methodology has been developed to control the production process of sugar-based depilatories. The method is based on the use of attenuated total reflectance—Fourier transform infrared (ATR-FTIR) spectroscopy in combination with multivariate data analysis. A very simple sample preparation process involving the dissolution of samples in water was applied. Employing a multivariate calibration model established from data of 15 well characterized samples, prediction errors equal or below 3.04 mg mL−1 for the quantitative determination of fructose, glucose, sucrose, maltose and maltotriose were obtained. Results found in this preliminary study indicate a g…
Chemical Element Levels as a Methodological Tool in Forensic Science
2014
The aim of the present study was to define a methodological strategy for understanding how post- mortem degradation in bones caused by the environment affects different skeletal parts and for selecting better preserved bone samples, employing rare earth elements (REEs) analysis and multivariate statistics. To test our methodological proposal the samples selected belong to adult and young individuals and were obtained from the Late Roman Necropolis of c/Virgen de la Misericordia located in Valencia city centre (Comunidad Valenciana, Spain). Therefore, a method for the determination of major elements, trace elements and REEs in bone remains has been developed employing Inductively-Coupled Pla…
Biomonitoring of polycyclic aromatic hydrocarbons in the urine of lactating mothers: Urinary levels, association with lifestyle factors, and risk ass…
2020
Abstract Polycyclic aromatic hydrocarbons (PAHs) are pollutants produced during incomplete combustion of organic matter and several industrial processes. Humans can be exposed to PAHs through ingestion of food, inhalation of tobacco smoke or polluted air, and dermal contact, causing immunologic, developmental, and reproductive problems. In the present research, eleven metabolites of PAHs were analyzed in the urine of 110 lactating women living in Spain (2015). PAH metabolites were extracted from the urine samples by liquid-liquid extraction and their determination was performed by liquid chromatography coupled to tandem mass spectrometry. In addition, information on lifestyle and dietary ha…
Application of point-to-point matching algorithms for background correction in on-line liquid chromatography–Fourier transform infrared spectrometry …
2009
A new background correction method for the on-line coupling of gradient liquid chromatography and Fourier transform infrared spectrometry has been developed. It is based on the use of a point-to-point matching algorithm that compares the absorption spectra of the sample data set with those of a previously recorded reference data set in order to select an appropriate reference spectrum. The spectral range used for the point-to-point comparison is selected with minimal user-interaction, thus facilitating considerably the application of the whole method. The background correction method has been successfully tested on a chromatographic separation of four nitrophenols running acetonitrile (0.08…
Determination of critical eluent composition for polyethylenglycols using on-line liquid chromatography-Fourier transform infrared spectrometry.
2008
In this work, it has been extended to methanol:water mobile phases, the use of a background correction method for on-line LC-FTIR measurements named Univariate background correction based on the use of a reference spectra matrix (UBC-RSM) and absorbance ratios. It permits to overcome the problem related to spectral changes occurring during the gradient elution, which in the past limited the on-line coupling of LC and FTIR to isocratic elutions. The combined use of the aforementioned background correction technique in on-line isocratic and gradient LC-FTIR, and partial least squares (PLS) has been applied for the search of the critical conditions for polymers. Polyethylenglycol (PEG) has bee…
Chemometric extraction of analyte-specific chromatograms in on-line gradient LC-infrared spectrometry
2009
This work exploits the possibilities offered by the recently developed multivariate method named Science-Based Calibration (SBC), for the extraction of ‘analyte-specific’ 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 (bopt(1)). Then, the bopt(1) vector is used to predict the concentration of the analyte of interest in the spect…
Biomonitoring of bisphenols A, F, S in human milk and probabilistic risk assessment for breastfed infants
2019
The present study addresses the presence of bisphenols A (BPA) and its analogs bisphenol F (BPF) and S (BPS) in milk of 120 mothers living in Valencia (Spain) and participating in the BETTERMILK project (year 2015). We also studied the factors that could influence the BPA levels and estimated the exposure and the risk for breast fed infants. The frequency of detection of total (conjugated + unconjugated) and unconjugated-BPA were 83% and 77%. with a geometric mean of 0.29 ng/mL and 0.15 ng/mL, respectively. The frequency of detection was much lower for total-BPF (22%) and total-BPS (1.1%). The place of residence of the mother and the use of personal care products showed significant associat…
ATR-Spin: an open-source 3D printed device for direct cytocentrifugation onto attenuated total reflectance crystals.
2021
Infrared Spectroscopy (IR) enables the direct and rapid characterization of cells at the molecular level. Achieving a rapid and consistent cell preparation is critical for the development of Point-of-Care diagnostics for cell analysis. Here we introduce an open-source, 3D printed device for integrating the isolation, preconcentration, and measurement of attenuated total reflectance IR spectra of cells from biofluids. The tool comprises a disposable card for cytocentrifugation, equipped with magnets, which allows reproducible integration into the pathlength of the IR spectrophotometer. Preliminary results using cell media containing A459 cells indicate that this system enables a qualitative …
Science based calibration for the extraction of 'analyte-specific' HPLC-DAD chromatograms in environmental analysis
2010
Multivariate science based calibration (SBC) has been applied to the resolution of overlapped peaks in liquid chromatography with diode array detection (LC-DAD). Complex river water samples spiked with 11 pharmaceutical substances resulted in poorly resolved chromatograms containing additional peaks from interfering matrix compounds and a change in the background absorbance due to the mobile phase gradient. Applying the present multivariate approach it was possible to resolve all 11 analytes from overlapping peaks, obtaining linear calibration lines (R2 > 0.96). Recovery percentages on spiked samples ranged between 74.6 and 113.5%, which are quite satisfactory taking into account the low co…
Direct determination of polymerised triacylglycerides in deep-frying vegetable oil by near infrared spectroscopy using Partial Least Squares regressi…
2012
Abstract A green method for the determination of polymerised triacylglyceride (PTG) in deep-frying vegetable oils of different botanic origin has been developed employing near infrared (NIR) spectroscopy and Partial Least Squares (PLS) regression. Four different types of oil were heated during several hours, with and without the addition of foodstuff. NIR transmission spectra were obtained directly from sample aliquots stored in glass vials, thus avoiding the consumption of solvents and minimising waste generation. Variables employed for building the PLS models were selected applying interval PLS (iPLS) as well as Uninformative Variable Elimination-PLS (UVE-PLS). A global PLS model using sp…
Comparing Targeted vs. Untargeted MS2 Data-Dependent Acquisition for Peak Annotation in LC-MS Metabolomics
2020
One of the most widely used strategies for metabolite annotation in untargeted LCMS is based on the analysis of MSn spectra acquired using data-dependent acquisition (DDA), where precursor ions are sequentially selected from MS scans based on user-selected criteria. However, the number of MSn spectra that can be acquired during a chromatogram is limited and a trade-off between analytical speed, sensitivity and coverage must be ensured. In this research, we compare four different strategies for automated MS2 DDA, which can be easily implemented in the frame of standard QA/QC workflows for untargeted LC&ndash
On-line gradient liquid chromatography–Fourier transform infrared spectrometry determination of sugars in beverages using chemometric background corr…
2008
Abstract An on-line gradient reversed phase liquid chromatography–Fourier transform infrared spectrometry (LC–FTIR) method was developed for the determination of fructose, glucose, sucrose and maltose in beverages. Improved chromatographic resolution was obtained using a linear gradient from 75 to 55% (v/v) acetonitrile in water in 15 min. Changes in the background spectra were corrected employing “univariate background correction based on the use of a reference spectra matrix” (UBC-RSM) and using the ratio of absorbance (AR) at 2256 and 2253 cm −1 for the identification of the eluent spectra within the RSM. The method provided limits of detection in the order of 0.75 mg ml −1 . The precisi…
Variación química intrasquelética relacionada a la diagénesis en los restos óseos de c/En Gil (Valencia)
2015
El objetivo de esto estudio ha sido definir una estrategia para una correcta selección de muestras de huesos inhumados (femures y costillas) menos afectados por los procesos diagéneticos, determinado los contenidos de elementos mayoritarios, trazas y REEs. Intentando en este modo de reconstruir el proceso de transición de los elementos desde el hueso al depósito tafonómico y viceversa. Una atenta selección de las muestras es determinante para que los análisis químicos puedan contribuir correctamente a una reconstrucción de la alimentación, las dinámicas de desplazamiento y las enfermedades de las poblaciones antiguas. Las muestras analizadas pertenecen a individuos hallados en las necr…
Analysis of longitudinal metabolomic data using multivariate curve resolution-alternating least squares and pathway analysis
2023
Extraction of meaningful biological information from longitudinal metabolomic studies is a major challenge and typically involves multivariate analysis and dimensional reduction methods for data visualization such as Principal Component Analysis or Multivariate Curve Resolution-Alternating Least Squares (MCR-ALS). Besides, a variety of computational tools have been developed to identify changes in metabolic pathways including functional analysis and pathway analysis. In this work, the joint analysis of results from MCR-ALS and metabolic pathway analysis is proposed to facilitate the interpretation of dynamic changes in longitudinal metabolomic data. The strategy is based on the use of MCR-A…
Biomonitoring of parabens in human milk and estimated daily intake for breastfed infants
2020
In this study, we assessed the presence of four parabens in human milk of 120 mothers from Valencia (Spain) which took part in a human biomonitoring project (BETTERMILK). The detection frequency ranges of parabens were 41-60% and 61-89% for unconjugated- and total (unconjugated + conjugated)-parabens, respectively. The concentrations ranged from <LoQ to 31 ng/mL and from <LoQ to 49 ng/mL for unconjugated- and total-parabens, respectively. The frequency of use of some cosmetic products and human milk protein levels were the main predictors of parabens in milk. The study evidences the presence of both conjugated and unconjugated paraben forms in human milk. The newborns estimated daily intake…
Determination of sugars in depilatory formulations: a green analytical method employing infrared detection and partial least squares regression.
2011
A green analytical method was developed for the analysis of sugar-based depilatories. Three independent partial least squares (PLS) regression models were built for the direct determination of glucose, fructose and maltose without any sample pretreatment based on their attenuated total reflectance - Fourier transform infrared (ATR-FTIR) spectra. The models showed adequate prediction capabilities with root-mean-square-errors of prediction ranging from 7.04 to 12.55 mg sugar g(-1) sample. As a reference procedure, gradient liquid chromatography with on-line infrared detection, employing background correction based on cubic smoothing splines, was used. The analysis revealed changes in the suga…
Detection of batch effects in liquid chromatography-mass spectrometry metabolomic data using guided principal component analysis.
2014
Metabolomics based on liquid chromatography-mass spectrometry (LC-MS) is a powerful tool for studying dynamic responses of biological systems to different physiological or pathological conditions. Differences in the instrumental response within and between batches introduce unwanted and uncontrolled data variation that should be removed to extract useful information. This work exploits a recently developed method for the identification of batch effects in high throughput genomic data based on the calculation of a delta statistic through principal component analysis (PCA) and guided PCA. Its applicability to LC-MS metabolomic data was tested on two real examples. The first example involved t…
Analytical potential of mid-infrared detection in capillary electrophoresis and liquid chromatography: a review.
2010
Literature published in the last decade concerning the use of mid-infrared spectrometry as a detection system in separation techniques employing a liquid mobile phase is reviewed. In addition to the continued use of isocratic liquid chromatographic (LC) techniques, advances in chemometric data evaluation techniques now allow the use of gradient techniques on a routine basis, thus significantly broadening the range of possible applications of LC-IR. The general trend towards miniaturized separation systems was also followed for mid-IR detection where two key developments are of special importance. Firstly, concerning on-line detection the advent of micro-fabricated flow-cells with inner volu…
Determination of lecithin and soybean oil in dietary supplements using partial least squares-Fourier transform infrared spectroscopy.
2008
Lecithin and soybean oil in dietary supplements were determined by Fourier transform infrared spectrometry transmission measurements in dichloromethane in combination with a partial least squares (PLS) regression. Two different PLS models were developed, using 16 synthetic mixtures of analytes in dichloromethane, making measurements in the spectral range from 931.8 to 1252.3 cm(-1) for lecithin and from 911.4 to 1246.9 cm(-1) and 1695.3 to 1774.5 cm(-1) for soybean oil. Seven products from the Spanish market with lecithin concentrations between 21.1% and 99.1% and soybean oil concentrations between 0% and 37.2% were analyzed by the proposed method and the data was compared to a chromatograp…
Exposure and Risk Assessment of Hg, Cd, As, Tl, Se, and Mo in Women of Reproductive Age Using Urinary Biomonitoring
2021
The present study analyzed the exposure and risk assessment of 4 toxic (Hg, Cd, As, Tl) and 2 essential (Se, Mo) elements in 119 Spanish women of reproductive age. The focus was on the elements for which risk-based benchmark, biomonitoring equivalents, or health-related human biomonitoring values have already been established. All elements presented frequencies of detection of 100% (greater than the limit of detection), except for Cd (99%). The 95th percentile concentrations were, for the toxic metals, 358.37 µg/L (total As), 1.10 µg/L (Cd), 0.41 µg/L (Tl), and 3.03 µg/L (total Hg) and, for the essential elements, 68.95 µg/L (total Se) and 154.67 (Mo). We examined sociodemographic factors a…
Analysis of the Association between Fatigue and the Plasma Lipidomic Profile of Inflammatory Bowel Disease Patients
2020
Inflammatory bowel disease (IBD) is a chronic, relapsing noninfectious inflammatory condition of the intestinal tract with two main phenotypes, ulcerative colitis (UC) and Crohn's disease (CD), and 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…
Protein-bound tyrosine oxidation, nitration and chlorination by-products assessed by ultraperformance liquid chromatography coupled to tandem mass sp…
2015
Abstract Background Free radicals cause alterations in cellular protein structure and function. Oxidized, nitrated, and chlorinated modifications of aromatic amino acids including phenylalanine and tyrosine are reliable biomarkers of oxidative stress and inflammation in clinical conditions. Objective To develop, validate and apply a rapid method for the quantification of known hallmarks of tyrosine oxidation, nitration and chlorination in plasma and tissue proteins providing a snapshot of the oxidative stress and inflammatory status of the organism and of target organs respectively. Material and Methods The extraction and clean up procedure entailed protein precipitation, followed by protei…
Background Correction and Multivariate Curve Resolution of Online Liquid Chromatography with Infrared Spectrometric Detection
2011
J.K. acknowledges the “V Segles” grant provided by the University of Valencia to carry out this study. Authors acknowledge the financial support of Ministerio de Educación y Ciencia (Projects AGL2007-64567 and CTQ2008-05719/BQU) and Conselleria d'Educació de la Generalitat Valenciana (Project PROMETEO 2010-055).
The effect of Holder pasteurization on the lipid and metabolite composition of human milk
2022
Human milk (HM) is the gold standard for newborn nutrition. When own mother's milk is not sufficiently available, pasteurized donor human milk becomes a valuable alternative. In this study we analyzed the impact of Holder pasteurization (HoP) on the metabolic and lipidomic composition of HM. Metabolomic and lipidomic profiles of twelve paired HM samples were analysed before and after HoP by liquid chromatography-mass spectrometry (MS) and gas chromatography-MS. Lipidomic analysis enabled the annotation of 786 features in HM out of which 289 were significantly altered upon pasteurization. Fatty acid analysis showed a significant decrease of 22 out of 29 detectable fatty acids. The observed c…
Modified locally weighted—Partial least squares regression improving clinical predictions from infrared spectra of human serum samples
2012
Locally weighted partial least squares regression (LW-PLSR) has been applied to the determination of four clinical parameters in human serum samples (total protein, triglyceride, glucose and urea contents) by Fourier transform infrared (FTIR) spectroscopy. Classical LW-PLSR models were constructed using different spectral regions. For the selection of parameters by LW-PLSR modeling, a multi-parametric study was carried out employing the minimum root-mean square error of cross validation (RMSCV) as objective function. In order to overcome the effect of strong matrix interferences on the predictive accuracy of LW-PLSR models, this work focuses on sample selection. Accordingly, a novel strateg…
New background correction approach based on polynomial regressions for on-line liquid chromatography-Fourier transform infrared spectrometry.
2008
Abstract In the present study a new approach for the chemometric background correction in on-line gradient LC–FTIR is introduced. For this purpose, the spectral changes of the elution mixture during gradient elution were analyzed applying 2D correlation spectroscopy. The fundamentals of the new background correction algorithm, based on polynomial fits calculated from a reference spectra matrix (Polyfit-RSM method) are explained. The Polyfit-RSM approach was applied on blank gradient runs as well as on LC–FTIR data obtained from the injection of a soft drink sample using acetonitrile:water as eluent. Results found were critically assessed and compared to those obtained by two previous backgr…
Towards a Rapid Screening of Liver Grafts at the Operating Room Using Mid-Infrared Spectroscopy
2020
The estimation of steatosis in a liver graft is mandatory prior to liver transplantation, as the risk of graft failure increases with the level of infiltrated fat. However, the assessment of liver steatosis before transplantation is typically based on a qualitative or semiquantitative characterization by visual inspection and palpation and histological analysis. Thus, there is an unmet need for transplantation surgeons to have access to a diagnostic tool enabling an in situ fast classification of grafts prior to extraction. In this study, we have assessed an attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopic method compatible with the requirements of an operatio…
Cubic smoothing splines background correction in on-line liquid chromatography–Fourier transform infrared spectrometry
2010
A background correction method for the on-line coupling of gradient liquid chromatography and Fourier transform infrared spectrometry (LC-FTIR) is proposed. The developed approach applies univariate background correction to each variable (i.e. each wave number) individually. Spectra measured in the region before and after each peak cluster are used as knots to model the variation of the eluent absorption intensity with time using cubic smoothing splines (CSS) functions. The new approach has been successfully tested on simulated as well as on real data sets obtained from injections of standard mixtures of polyethylene glycols with four different molecular weights in methanol:water, 2-propano…
Metabolomic Diversity of Human Milk Cells over the Course of Lactation—A Preliminary Study
2023
Human milk (HM) is a complex biofluid containing a wide cell variety including epithelial cells and leukocytes. However, the cellular compositions and their phenotypic properties over the course of lactation are poorly understood. The aim of this preliminary study was to characterize the cellular metabolome of HM over the course of lactation. Cells were isolated via centrifugation and the cellular fraction was characterized via cytomorphology and immunocytochemical staining. Cell metabolites were extracted and analyzed using ultra-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UPLC–QqTOF-MS) in the positive and negative electrospray ionization mode…
Biological mineral content in Iberian skeletal cremains for control of diagenetic factors employing multivariate statistics
2013
Abstract The aim of this study was to define a strategy for a correct selection of bone samples by employing inductively coupled plasma optical emission spectroscopy (ICP-OES) for reconstructing the biological mineral content in bones through the determination of major elements, trace elements and Rare Earth Elements (REE, lanthanides) in skeletal cremains of ancient Iberians (III–II B.C), discovered in the Necropolis of Corral de Saus (Moixent, Valencia) between 1972 and 1979. The biological mineral content was determined taking into account diagenetic factors. A control method for a better reading of results was applied. To explore large geochemical datasets and to reduce the number of va…
Procedure for automated background correction in flow systems with infrared spectroscopic detection and changing liquid-phase composition
2009
This paper describes a partial least squares (PLS) based automatic procedure to correct for changes in the spectral contribution of the solvent or solvent mixtures from solute spectra recorded in these solvents. The procedure was developed for successful on-line Fourier transform infrared (FT-IR) detection in gradient high-performance liquid chromatography (HPLC) separations. It requires a reference FT-IR data set containing all possible combinations of the expected variation in solvent composition. Furthermore, a spectral region ( A) in these spectra is required where the solvents show absorption but the analytes do not. This is the case for the system ACN:H2O, an often-applied solvent mi…
New cut-off criterion for uninformative variable elimination in multivariate calibration of near-infrared spectra for the determination of heroin in …
2008
A new cut-off criterion has been proposed for the selection of uninformative variables prior to chemometric partial least squares (PLS) modelling. After variable elimination, PLS regressions were made and assessed comparing the results with those obtained by PLS models based on the full spectral range. To assess the prediction capabilities, uninformative variable elimination (UVE)-PLS and PLS were applied to diffuse reflectance near-infrared spectra of heroin samples. The application of the proposed new cut-off criterion, based on the t-Students distribution, provided similar predictive capabilities of the PLS models than those obtained using the original criteria based on quantile value. H…
On-Capillary Surface-Enhanced Raman Spectroscopy: Determination of Glutathione in Whole Blood Microsamples.
2018
Oxidative stress monitoring in the neonatal period supports early outcome prediction and treatment. Glutathione (GSH) is the most abundant antioxidant in most cells and tissues, including whole blood, and its usefulness as a biomarker has been known for decades. To date, the available methods for GSH determination require laborious sample processing and the use of sophisticated laboratory equipment. To the best of our knowledge, no tools suitable for point-of-care (POC) sensing have been reported. Surface-enhanced Raman spectroscopy (SERS), performed in a microvolume capillary measurement cell, is proposed in this study as a robust approach for the quantification of GSH in human whole blood…
Does Pasteurized Donor Human Milk Efficiently Protect Preterm Infants Against Oxidative Stress?
2019
International audience; Pasteurized donor human milk (DHM) is the preferred alternative for infant nutrition when own mother's milk (OMM) is unavailable. Whether DHM is an efficient means for protecting preterm infants from oxidative stress remains unknown. We quantified a panel of oxidative stress biomarkers in urine samples from preterm infants (≤32 weeks of gestation and a birth weight ≤1500 g) receiving ≥80% of feeding volume as either DHM or OMM. The noninvasive in vivo assessment of oxidative stress showed no statistically significant difference between both groups at the time when full enteral nutrition (150 mL/kg body weight) was achieved and until hospital discharge. In addition, t…
Assessment of the statistical significance of classifications in infrared spectroscopy based diagnostic models.
2014
Fourier transform infrared (IR) spectroscopy in combination with multivariate data analysis is a versatile tool that can be applied to disease diagnosis. However, a rigorous validation of the obtained models is necessary in order to obtain robust results. This work evaluates the advantages of the use of permutation testing for determining the statistical significance of the misclassification errors obtained from IR based diagnostic models through cross validation (CV). The model performance, estimated by CV, is compared to a distribution of CV-performance values obtained using randomly permuted class labels. The distribution of ‘random CV-values’ is considered as a null distribution and use…
Prolonging in utero-like oxygenation after birth diminishes oxidative stress in the lung and brain of mice pups☆
2013
Background Fetal-to-neonatal transition is associated with oxidative stress. In preterm infants, immaturity of the antioxidant system favours supplemental oxygen-derived morbidity and mortality. Objectives To assess if prolonging in utero-like oxygenation during the fetal-to-neonatal transition limits oxidative stress in the lung and brain, improving postnatal adaptation of mice pups. Material and methods Inspiratory oxygen fraction (FiO2) in pregnant mice was reduced from 21% (room air) to 14% (hypoxia) 8–12 h prior to delivery and reset to 21% 6–8 h after birth. The control group was kept at 21% during the procedure. Reduced (GSH) and oxidized (GSSG) glutathione and its precursors [γ-glut…
Impact of Donor Human Milk in the Preterm Very Low Birth Weight Gut Transcriptome Profile by Use of Exfoliated Intestinal Cells
2019
[Background] Own mother’s milk (OMM) is the optimal nutrition for preterm infants. However, pasteurized donor human milk (DHM) is a valid alternative. We explored the differences of the transcriptome in exfoliated epithelial intestinal cells (EEIC) of preterm infants receiving full feed with OMM or DHM.
Advanced Spectroscopic Detectors for Identification and Quantification
2013
The coupling of vibration spectroscopic detectors to liquid chromatography (LC) is an interesting analytical tool that allows combining high resolution from LC with molecular specific information accessible by infrared (IR) and Raman spectrometry. This chapter describes the basics of IR and Raman spectroscopy with a special emphasis on the advantages and pitfalls of these detection techniques in LC. Two fundamentally different coupling approaches, namely, off-line hyphenation involving the physical elimination of the mobile phase and on-line hyphenation through the use of flow cells, are discussed in detail, describing the most important interfaces and diverse practical applications. Strate…
Infrared biospectroscopy for a fast qualitative evaluation of sample preparation in metabolomics.
2014
Liquid chromatography-mass spectrometry (LC-MS) has been increasingly used in biomedicine to study the dynamic metabolomic responses of biological systems under different physiological or pathological conditions. To obtain an integrated snapshot of the system, metabolomic methods in biomedicine typically analyze biofluids (e.g. plasma) that require clean-up before being injected into LC-MS systems. However, high resolution LC-MS is costly in terms of resources required for sample and data analysis and care must be taken to prevent chemical (e.g. ion suppression) or statistical artifacts. Because of that, the effect of sample preparation on the metabolomic profile during metabolomic method d…
UV resonance Raman spectroscopy: a process analytical tool for host cell DNA and RNA dynamics in mammalian cell lines
2014
BACKGROUND Recent advances in Raman spectroscopy have resulted in the development of rapid, in situ Raman probes that can identify and allow the assessment of the quality of complex constituents in mammalian cell culture. One specific Raman technique, UV resonance Raman (UVRR) spectroscopy, has potential as a probe for residual cellular DNA and RNA in mammalian cell culture medium. RESULTS Variations in DNA and RNA UVRR spectral profiles of medium-cellular footprint samples were identified and related to time of harvest and increased cell lysis that is associated with a loss in cell viability. Increased DNA and RNA were also observed in the cell culture supernatant in response to sodium but…
Assessment of oxidative damage to proteins and DNA in urine of newborn infants by a validated UPLC-MS/MS approach
2014
The assessment of oxidative stress is highly relevant in clinical Perinatology as it is associated to adverse outcomes in newborn infants. This study summarizes results from the validation of an Ultra Performance Liquid Chromatography-tandem Mass Spectrometry (UPLC-MS/MS) method for the simultaneous quantification of the urinary concentrations of a set of endogenous biomarkers, capable to provide a valid snapshot of the oxidative stress status applicable in human clinical trials, especially in the field of Perinatology. The set of analytes included are phenylalanine (Phe), para-tyrosine (p-Tyr), ortho-tyrosine (o-Tyr), meta-tyrosine (m-Tyr), 3-NO2-tyrosine (3NO(2)-Tyr), 3-Cl-tyrosine (3Cl-T…
On-line gel permeation chromatography–attenuated total reflectance–Fourier transform infrared determination of lecithin and soybean oil in dietary su…
2007
Gel permeation chromatography (GPC) with attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectrometry detection has been proposed for the simultaneous determination of lecithin and soybean oil in dietary supplements. The method involves the extraction of analytes with dichloromethane in an ultrasound water bath and the injection of 2 ml of centrifuged and filtered extracts into the system integrated by two Envirogel GPC columns (19 mm x150 mm, 19 mm x 300 mm) coupled on-line. Dichloromethane was used as mobile phase. A method has been developed to select the most appropriated wavenumber to be used for the determination of each considered compound from the calculation of a…
Analysis of multi-source metabolomic data using joint and individual variation explained (JIVE).
2015
Metabolic profiling is increasingly being used for understanding biological processes but there is no single analytical technique that provides a complete quantitative or qualitative profiling of the metabolome. Data fusion (i.e. joint analysis of data from multiple sources) has the potential to circumvent this issue facilitating knowledge discovery and reliable biomarker identification. Another field of application of data fusion is the simultaneous analysis of metabolomic changes through several biofluids or tissues. However, metabolomics typically deals with large datasets, with hundreds to thousands of variables and the identification of shared and individual factors or structures acros…
A rapid method for the differentiation of yeast cells grown under carbon and nitrogen-limited conditions by means of partial least squares discrimina…
2012
This paper shows the ease of application and usefulness of mid-IR measurements for the investigation of orthogonal cell states on the example of the analysis of Pichia pastoris cells. A rapid method for the discrimination of entire yeast cells grown under carbon and nitrogen-limited conditions based on the direct acquisition of mid-IR spectra and partial least squares discriminant analysis (PLS-DA) is described. The obtained PLS-DA model was extensively validated employing two different validation strategies: (i) statistical validation employing a method based on permutation testing and (ii) external validation splitting the available data into two independent sub-sets. The Variable Importa…
Metabolomic Analysis of the Effect of Postnatal Hypoxia on the Retina in a Newly Born Piglet Model
2013
The availability of reliable biomarkers of brain injury secondary to birth asphyxia could substantially improve clinical grading, therapeutic intervention strategies, and prognosis. In this study, changes in the metabolome of retinal tissue caused by profound hypoxia in an established neonatal piglet model were investigated using an ultra performance liquid chromatography - quadrupole time of flight mass spectrometry (UPLC-QTOFMS) untargeted metabolomic approach, which included Partial Least Squares - Discriminant Analysis (PLSDA) multivariate data analysis. The initial identification of a set of discriminant metabolites from UPLC-QTOFMS data was confirmed by target UPLC-MS/MS and allowed t…
Monitoring of system conditioning after blank injections in untargeted UPLC-MS metabolomic analysis
2019
AbstractUltra-performance liquid chromatography – mass spectrometry (UPLC-MS) is widely used for untargeted metabolomics in biomedical research. To optimize the quality and precision of UPLC-MS metabolomic analysis, evaluation of blank samples for the elimination of background features is required. Although blanks are usually run either at the beginning or at the end of a sequence of samples, a systematic analysis of their effect of the instrument performance has not been properly documented. Using the analysis of two common bio-fluids (plasma and urine), we describe how the injection of blank samples within a sequence of samples may affect both the chromatographic and MS detection performa…
ATR-FTIR spectroscopy for the routine quality control of exosome isolations
2021
Abstract Exosomes are nanosized vesicles containing specific cargos of DNA, RNA, proteins, metabolites, and intracellular and membrane lipids. Exosome isolation needs to be optimized carefully depending on the type of biofluid and tissue and the retrieved exosomes need to be characterized. The main objective of this study was to determine the feasibility of a multimodal analysis of Attenuated Total Reflectance – Fourier Transform Infrared (ATR-FTIR) spectroscopy and UPLC–QqTOF-MSMS for the development of a routine quality control tool of isolated exosomes and the rapid characterization of their lipid profiles and total protein content. Using human milk as model example, exosomes were isolat…
Data set: Towards a rapid screening of liver grafts at the operating room using mid-infrared spectroscopy
2020
The estimation of steatosis in a liver graft is mandatory prior to liver transplantation, as the risk of graft failure increases with the level of infiltrated fat. However, the assessment of liver steatosis before transplantation is typically based on a qualitative or semi-quantitative characterization by visual inspection and palpation, and histological analysis. Thus, there is an unmet need for transplantation surgeons to have access to a diagnostic tool enabling an in situ fast classification of grafts prior extraction. In this study, we have assessed an Attenuated Total Reflection-Fourier Transform Infrared (ATR-FTIR) spectroscopic method compatible with the requirements of an operation…
Data set: Towards a rapid screening of liver grafts at the operating room using mid-infrared spectroscopy
2020
The estimation of steatosis in a liver graft is mandatory prior to liver transplantation, as the risk of graft failure increases with the level of infiltrated fat. However, the assessment of liver steatosis before transplantation is typically based on a qualitative or semi-quantitative characterization by visual inspection and palpation, and histological analysis. Thus, there is an unmet need for transplantation surgeons to have access to a diagnostic tool enabling an in situ fast classification of grafts prior extraction. In this study, we have assessed an Attenuated Total Reflection-Fourier Transform Infrared (ATR-FTIR) spectroscopic method compatible with the requirements of an operation…
Data set: Towards a rapid screening of liver grafts at the operating room using mid-infrared spectroscopy
2020
The estimation of steatosis in a liver graft is mandatory prior to liver transplantation, as the risk of graft failure increases with the level of infiltrated fat. However, the assessment of liver steatosis before transplantation is typically based on a qualitative or semi-quantitative characterization by visual inspection and palpation, and histological analysis. Thus, there is an unmet need for transplantation surgeons to have access to a diagnostic tool enabling an in situ fast classification of grafts prior extraction. In this study, we have assessed an Attenuated Total Reflection-Fourier Transform Infrared (ATR-FTIR) spectroscopic method compatible with the requirements of an operation…