Tandem mass spectrometry of serum cholestanoic (C) acids - Typical concentration ranges and application to the study of peroxisomal biogenesis disorders.

Background: Primary bile acid synthesis is impaired in peroxisomal disorders, leading to the accumulation of long-chain bile acids, specifically dihydroxycholestanoic and trihydroxycholestanoic acids. Quantification of the diastereoisomers of these C bile acids is essential for the differential diagnosis of these disorders.

Methods: High-performance liquid chromatography electrospray ionization-tandem mass spectrometry with stable-isotope dilution was used to quantify all eight diastereoisomers of cholestanoic acids in serum.

Essential Fatty Acid Deficiency Associates with Growth Faltering and Environmental Enteric Dysfunction in Children.

Environmental enteric dysfunction (EED) is characterized by intestinal inflammation, malabsorption and growth-faltering in children with heightened exposure to gut pathogens. The aim of this study was to characterize serum non-esterified fatty acids (NEFA), in association with childhood undernutrition and EED, as potential biomarkers to predict growth outcomes. The study comprised a cohort of undernourished rural Pakistani infants ( = 365) and age-matched controls followed prospectively up to 24 months of age.

Cholestasis impairs gut microbiota development and bile salt hydrolase activity in preterm neonates.

Cholestasis refers to impaired bile flow from the liver to the intestine. In neonates, cholestasis causes poor growth and may progress to liver failure and death. Normal bile flow requires an intact liver-gut-microbiome axis, whereby liver-derived primary bile acids are transformed into secondary bile acids.

Serum bile acids as a prognostic biomarker in biliary atresia following Kasai portoenterostomy.

Background And Aims: In biliary atresia, serum bilirubin is commonly used to predict outcomes after Kasai portoenterostomy (KP). Infants with persistently high levels invariably need liver transplant, but those achieving normalized levels have a less certain disease course. We hypothesized that serum bile acid levels could help predict outcomes in the latter group.

Risk Factors for Bile Aspiration and its Impact on Clinical Outcomes.

Introduction: Bile reflux may cause for lung allograft rejection, yet there are no studies that determine (i) the relationship between gastric and lung bile concentrations, (ii) whether bile is present in lungs of nontransplant patients, (iii) the relationship between gastric dysmotility and lung bile, (iv) the impact of reflux therapies on lung bile, and (v) whether lung bile worsens outcomes in nontransplant patients. This study will address these gaps in the literature.

Methods: We prospectively recruited lung transplant (LTX) patients and nontransplant patients with respiratory symptoms (RP) and collected paired gastric and lung samples.

The impact of gastrointestinal dysmotility on the aerodigestive microbiome of pediatric lung transplant recipients.

Background: Delayed gastric emptying has been associated with increased graft rejection, although the mechanism of this association is not known. This study aims to investigate the interrelationship between delays in gastrointestinal motility and the diversity and composition of gastric, oropharyngeal, and lung microbiomes in pediatric lung transplant recipients.

Methods: We prospectively recruited 23 pediatric lung transplant recipients and 98 pediatric patients with respiratory symptoms undergoing combined endoscopy and bronchoscopy.

Utilizing centralized biorepository samples for biomarkers of cystic fibrosis lung disease severity.

Background: Circulating biomarkers reflective of lung disease activity and severity have the potential to improve patient care and accelerate drug development in CF. The objective of this study was to leverage banked specimens to test the hypothesis that blood-based biomarkers discriminate CF children segregated by lung disease severity.

Methods: Banked serum samples were selected from children who were categorized into two extremes of phenotype associated with lung function ('mild' or 'severe') based on CF-specific data and were matched on age, gender, CFTR genotype, and P.

Accurate mass and retention time library of serum lipids for type 1 diabetes research.

Dysregulated lipid species are linked to various disease pathologies and implicated as potential biomarkers for type 1 diabetes (T1D). However, it is challenging to comprehensively profile the blood specimen lipidome with full structural details of every lipid molecule. The commonly used reversed-phase liquid chromatography-tandem mass spectrometry (RPLC-MS/MS)-based lipidomics approach is powerful for the separation of individual lipid species, but lipids belonging to different classes may still co-elute and result in ion suppression and misidentification of lipids.

Off-line mixed-mode liquid chromatography coupled with reversed phase high performance liquid chromatography-high resolution mass spectrometry to improve coverage in lipidomics analysis.

The confident identification and in-depth profiling of molecular lipid species remain to be a challenge in lipidomics analysis. In this work, an off-line two-dimensional mixed-mode and reversed-phase liquid chromatography (RPLC) method combined with high-field quadrupole orbitrap mass spectrometer (Q Exactive HF) was developed to profile lipids from complex biological samples. In the first dimension, 22 different lipid classes were separated on a monolithic silica column with elution order from neutral to polar lipids.

Comprehensive untargeted lipidomic analysis using core-shell C30 particle column and high field orbitrap mass spectrometer.

The goal of untargeted lipidomics is to have high throughput, yet comprehensive and unambiguous identification and quantification of lipids. Novel stationary phases in LC separation and new mass spectrometric instruments capable of high mass resolving power and faster scanning rate are essential to achieving this goal. In this work, 4 reversed phase LC columns coupled with a high field quadrupole orbitrap mass spectrometer (Q Exactive HF) were thoroughly compared using complex lipid standard mixture and rat plasma and liver samples.

A new SPE/GC-fid method for the determination of cholesterol oxidation products. Application to subcutaneous fat from Iberian dry-cured ham.

A new method for the isolation and analysis of cholesterol oxidation products (COPs) using solid phase extraction (SPE) and silica columns was developed using gas chromatography-flame ion detection (GC-FID). The method comprises of saponification and liquid-liquid extraction of the unsaponifiable fraction prior to the isolation and derivatization of the COPs to trimethylsilyl ethers. The COPs used in this study are cholestane-5α-6α-epoxide, cholestane-3β-5α-6β-triol, 25-hydroxycholesterol and 5-cholesten-3β-ol-7-one.

Feasibility of use of fatty acid and triacylglycerol profiles for the authentication of commercial labelling in Iberian dry-cured sausages.

In the present study, fatty acid and triacylglycerol profiles were used to evaluate the possibility of authenticating Iberian dry-cured sausages according to their label specifications. 42 Commercial brand 'chorizo' and 39 commercial brand 'salchichón' sausages from Iberian pigs were purchased. 36 Samples were labelled Bellota and 45 bore the generic Ibérico label.

Subcutaneous fat triacylglycerols profile from Iberian pigs as a tool to differentiate between intensive and extensive fattening systems.

Triacylglycerols of subcutaneous fat of Iberian pigs reared on two different feeding systems, extensive and intensive, have been determined by gas chromatography with a flame ionization detector. Analyses were performed on a column coated with a bonded stationary phase (50% phenyl-50% methylpolysiloxane) with hydrogen as the carrier gas. Lipids were extracted by melting the subcutaneous fat in a microwave oven and then filtering and dissolving in hexane.

A new high-performance liquid chromatographic method with evaporative light scattering detector for the analysis of phospholipids. Application to Iberian pig subcutaneous fat.

A new method for the analysis of phospholipids by normal-phase HPLC is described using a silica column. Addition of ammonia and triethylamine to a gradient based on chloroform/methanol/water promoted a good and rapid separation of phospholipid classes (20 min run). The use of an evaporative light scattering detector permitted an accurate analysis of a mixture of phospholipids.

Volatile hydrocarbon profile of Iberian dry-cured hams. A possible tool for authentication of hams according to the fattening diet.

The aims of this work were to carry out a comprehensive study of the volatile hydrocarbons of 34 Iberian dry-cured hams and to evaluate the efficiency of these compounds for discriminating hams according to the fattening system: "Montanera" (B) and "Cebo" (C). The samples of hams were obtained by mincing the semimembranosus and semitendinosus muscles from slices of dry-cured ham. The analyses were carried out by gas chromatography-mass spectrometry with a polar capillary column and after a previous extraction by Purge and Trap method.

Authentication of fattening diet of goat kid according to their fatty acid profile from perirenal fat.

Fatty acids of forty-two samples of perirenal fat of goat kids reared on three different feeding systems: goat milk (B), milk replacer (R) and milk-based starter (F) have been analyzed by Gas Chromatography flame ionization detector. The lipids were extracted by melting of perirenal fat in a microwave oven. The fat was then filtered and dissolved in hexane.

Determination of ent-kaurene in subcutaneous fat of Iberian pigs by gas chromatography multi-stage mass spectrometry with the aim to differentiate between intensive and extensive fattening systems.

This work presents a gas chromatography multi-stage mass spectrometry (GC-MS(3)) method for the determination of ent-kaurene in subcutaneous fat of Iberian pig, present in adipose tissue of animals due to pasture ingestion (extensive fattening system). The method comprises a saponification and a liquid-liquid extraction of the unsaponifiable fraction, followed by an isolation of the hydrocarbon fraction by high performance liquid chromatography (HPLC) and analysis by GC-MS(3) (ion trap) with electronic ionization. The GC-MS(3) analysis allows the isolation and characterization of specific fragments from the original (MS(1)) molecular structure, and particularly, those fragments originated from the precursor ion (m/z=229) characteristic of ent-kaurene.

Changes in the fatty acid and triacylglycerol profiles in the subcutaneous fat of Iberian ham during the dry-curing process.

In this study, we have evaluated the changes that occur in the profiles of total fatty acids and triacylglycerols during the dry-curing process (730 days) of Iberian ham. The subcutaneous adipose tissues of six hams obtained from three Iberian pigs fed on acorns were analyzed periodically during the processing time (from the raw to the dry-cured samples), including postsalting, drying, and ripening stages. The environmental conditions were also registered.

Changes in the concentrations of free fatty acid, monoacylglycerol, and diacylglycerol in the subcutaneous fat of Iberian ham during the dry-curing process.

Changes in diacylglycerols, monoacylglycerols, and free fatty acid composition of subcutaneous fat of six Iberian hams during the dry-cured process were investigated. In addition, an analytical method for simultaneous quantification of diacylglycerols, monoacylglycerols, and free fatty acid by solid-phase extraction-gas chromatography was developed. The different molecular species of free fatty acids, monoacylglycerols, and diacylglycerols and 1,2- and 1,3-isomers of diacylglycerols have been described for the first time in this type of sample.