The emerging disciplines of lipidomics and metabolomics show great potential for the discovery of diagnostic biomarkers, but appropriate pre-analytical sample-handling procedures are critical because several analytes are prone to ex vivo distortions during sample collection. To test how the intermediate storage temperature and storage period of plasma samples from K3EDTA whole-blood collection tubes affect analyte concentrations, we assessed samples from non-fasting healthy volunteers (n = 9) for a broad spectrum of metabolites, including lipids and lipid mediators, using a well-established LC-MS-based platform. We used a fold change-based approach as a relative measure of analyte stability to evaluate 489 analytes, employing a combination of targeted LC-MS/MS and LC-HRMS screening. The concentrations of many analytes were found to be reliable, often justifying less strict sample handling; however, certain analytes were unstable, supporting the need for meticulous processing. We make four data-driven recommendations for sample-handling protocols with varying degrees of stringency, based on the maximum number of analytes and the feasibility of routine clinical implementation. These protocols also enable the simple evaluation of biomarker candidates based on their analyte-specific vulnerability to ex vivo distortions. In summary, pre-analytical sample handling has a major effect on the suitability of certain metabolites as biomarkers, including several lipids and lipid mediators. Our sample-handling recommendations will increase the reliability and quality of samples when such metabolites are necessary for routine clinical diagnosis.

Mass spectrometry (MS)-based clinical proteomic Laboratory Developed Tests (LDTs) for the measurement of protein biomarkers related to endocrinology, cardiovascular disease, cancer, and Alzheimer\'s disease are gaining traction in clinical laboratories due to their value in supporting diagnostic and treatment decisions for patients. Under the current regulatory landscape, MS-based clinical proteomic LDTs are regulated by Clinical Laboratory Improvement Amendments (CLIA) under the auspices of the Centers for Medicaid and Medicare Services (CMS). However, should the Verifying Accurate Leading-Edge In Vitro Clinical Test Development (VALID) Act pass, it will grant the FDA greater authority to oversee diagnostic tests, including LDTs. This could impede clinical laboratories\' ability to develop new MS-based proteomic LDTs to support existing and emerging patient care needs. Therefore, this review discusses the currently available MS-based proteomic LDTs and their current regulatory landscape in the context of the potential impacts imposed by the passage of the VALID Act.

World trends in oil crop growing area, yield, and production over the last 10 years exhibited an increase of 48 %, 82 %, and 240 %, respectively. Concerning reduced shelf-life of oil-containing food products caused by oil oxidation and the demand for sensory quality of oil, the development of methods the improvement oil quality is urgently required. This critical review presented a concise overview of the recent literature related to the inhibition ways of oil oxidation. The mechanism of different antioxidants and nanoparticle delivery systems on oil oxidation was also explored. The current review provides scientific findings on control strategies: (i) design oxidation quality assessment model; (ii) packaging by antioxidant coatings and eco-friendly film nanocomposite: ameliorate physicochemical properties; (iii) molecular investigations on inhibitory effects of selected antioxidants and underlying mechanisms; (iv) explore the interrelationship between the cysteine/citric acid and lipoxygenase pathway in the progression of oxidative/fragmentation degradation of unsaturated fatty acid chains.

UNASSIGNED: The sample matrix composition, which is greatly affected by the type of blood collection tube used during phlebotomy, is of major importance in laboratory testing as it can influence test results. We developed an LC-MRM-MS test to molecularly characterize antithrombin in citrate plasma. The test principle differs greatly from traditional laboratory tests and the influence of varying plasma sample matrices is largely unknown.
UNASSIGNED: To identify whether variations in sample matrix affect the LC-MRM-MS test for antithrombin and assess whether sample pre-processing by immunocapture reduces matrix-specific effects.
UNASSIGNED: Samples (n = 45) originating from four different blood collection tubes (sodium citrate, lithium heparin, K2-EDTA and K2-EDTA with protease inhibitors) were processed directly or after immunocapture. Antithrombin was digested into proteotypic peptides, which were monitored by LC-MRM-MS. Results from lithium heparin and the K2-EDTA matrices were compared to the standard sample matrix, sodium citrate, using Deming regression analysis and repeated measures one-way ANOVA.
UNASSIGNED: Deming regression analysis of directly processed samples revealed slopes deviating >5% from the line of identity for at least six out of 22 peptides in all matrices. Significant differences between all matrices were found upon analysis by ANOVA for at least 10 peptides. Pre-processing by immunocapture led to slopes within 5% of the line of identity for nearly all peptides of the matrices. Furthermore, significant differences between matrices after immunocapture were only observed for four peptides.
UNASSIGNED: Variations in the sample matrix affect the measurement of antithrombin by LC-MRM-MS, but observed effects are greatly reduced upon pre-processing by immunocapture.

The need for high-throughput analysis of multiple analytes for inborn errors of metabolism in newborn screening (NBS) has led to the introduction of tandem mass spectrometry (MS/MS) into the NBS laboratory. In a flow-injection analysis (FIA), the predominant MS/MS method utilized for NBS, samples are introduced directly into the mass spectrometer without chromatographic separation. When a high-throughput FIA-based MS/MS method is implemented on newer generations of mass spectrometers with increased sensitivity, the risk of carryover and contamination increases. In the present study, we report the carryover of ornithine identified during the implementation of the NeoBase™ 2 (PerkinElmer) non-derivatized kits on the Xevo-TQD platform (Waters Corporation) and describe the source of the carryover, which was traced to the stainless-steel frit-type inline filter. Furthermore, a possible compound-dependent interaction with the stainless-steel frit is suggested based on the structure of ornithine and its effect on separation techniques. Investigation and mitigation of carryover can be a time and resource consuming process, and to this end, our report on identification of a stainless-steel frit as the source of delayed elution and carryover of ornithine should be recognized as a rare, albeit possible source of carryover in FIA-MS/MS methods adopted for NST.

UNASSIGNED: Highly selective and sensitive multi-analyte methods for the analysis of steroids are attractive for the diagnosis of endocrine diseases. Commercially available kits are increasingly used for this purpose. These methods involve laborious solid phase extraction, and the respective panels of target analytes are incomplete. We wanted to investigate whether an improvement of kit solutions is possible by introducing automated on-line solid phase extraction (SPE) and combining originally separate analyte panels.
UNASSIGNED: Sample preparation was performed using automated on-line SPE on a high-pressure stable extraction column. Chromatographic separation, including isobaric compounds, was achieved using a 0.25 mM ammonium fluoride-methanol gradient on a small particle size biphenyl column. Standard compounds and internal standard mixtures of two panels of a commercially available kit were combined to achieve an optimized and straightforward detection of 15 endogenous steroids. Validation was performed according to the European Medicines Agency (EMA) guidelines with slight modifications.
UNASSIGNED: Validation was successfully performed for all steroids over a clinically relevant calibration range. Deviations of intra- and inter-assay accuracy and precision results passed the criteria and no relevant matrix effects were detected due to highly effective sample preparation. External quality assessment samples showed the applicability as a routine diagnostic method, which was affirmed by the analyses of anonymized clinical samples.
UNASSIGNED: It was found possible to complement a commercially available kit for quantitative serum steroid profiling based on isotope dilution LC-MS/MS by implementing automated on-line SPE, thereby improving the practicality and robustness of the measurement procedure.

Regulations often are imposing long postmortem times before autopsy leading to certain toxicity-unrelated changes in biomarkers, which in turn may affect the reliability of toxicity evaluation during forensic investigations. Since methomyl pesticide shows significant toxicity and is frequently encountered in poisoning cases, the current study evaluated different parameters in methomyl intoxicated rats at three different postmortem intervals (Hour 0, Hour 3 and Hour 6). Eighteen adult Sprague Dawley rats were poisoned with methomyl to simulate actual methomyl poisoning cases. The time of death was assigned as Hour 0. The animals were divided into 3 groups (n = 6) to collect blood and tissue samples at the selected time points. Body weight, relative organ weight, protein concentration, methomyl concentration and acetylcholinesterase activity (AChE) were assessed in blood and different tissues (liver, spleen, kidney, brain, eye, and bone marrow) to evaluate the effect of postmortem sampling time. Outcomes revealed significant decreases in methomyl concentration in blood and bone marrow with advanced sampling time (P < 0.001). Similarly, there were significant reductions in AChE activity in the kidney (P < 0.01), while the enzyme activity significantly increased in brain samples (P < 0.05). Findings illustrated the importance of sampling time in toxicity studies because it could alter experimental results and impact consequent interpretations, as well as it may alter postmortem biomarkers in related forensic cases.

UNASSIGNED: Exposure to poly- and perfluoroalkyl substances (PFAS), a class of persistent organic pollutants, is ubiquitous. Animal studies suggest that PFAS may increase risk of fatty liver and hepatocellular carcinoma (HCC) via impacts on hepatic lipid, amino acid, and glucose metabolism, but human data is lacking. We examined associations between PFAS exposure, altered metabolic pathways, and risk of non-viral HCC.
UNASSIGNED: In this nested case-control study, pre-diagnostic plasma PFAS and metabolomics were measured in 50 incident HCC cases and 50 individually matched controls from the Multiethnic Cohort (MEC) study. Cases/controls were matched by age, sex, race, and study area. PFAS exposure and risk of HCC were examined using conditional logistic regression. A metabolome-wide association study and pathway enrichment analysis was performed for PFAS exposure and HCC risk, and key metabolites/metabolic pathways were identified using a meet in the middle approach.
UNASSIGNED: High perfluorooctane sulfonic acid (PFOS) levels (90th percentile from NHANES; >55 μg/L) were associated with 4.5-fold increased risk of HCC (odds ratio 4.5, 95% CI 1.2-16.0). Pathway enrichment analysis showed that PFOS exposure was associated with alterations in amino acid and glycan biosynthesis pathways, which were also associated with HCC risk. We identified 4 metabolites linking PFOS exposure with HCC, including glucose, butyric acid (a short-chain fatty acid), α-ketoisovaleric acid (a branched-chain α-keto acid), and 7α-hydroxy-3-oxo-4-cholestenoate (a bile acid), each of which was positively associated with PFOS exposure and risk of HCC.
UNASSIGNED: This proof-of-concept analysis shows that exposure to high PFOS levels was associated with increased risk of non-viral HCC, likely via alterations in glucose, amino acid, and bile acid metabolism. Larger studies are needed to confirm these findings.
UNASSIGNED: Per- and polyfluoroalkyl substances (PFAS), often referred to as \"forever chemicals\" because they are difficult to break down and stay in the human body for years, are extremely common and can cause liver damage. In a first of its kind study, we found that exposure to high levels of perfluorooctanesulfonic acid, one of the most common PFAS chemicals, was linked to increased risk of hepatocellular carcinoma in humans. Hepatocellular carcinoma is difficult to treat and is one of the most common forms of liver cancer, and these findings may provide new avenues for helping to prevent this disease.

Antimicrobial resistance is increasing in prevalence and there is a clear need for the development of rapid detection methods in clinical diagnostics. This review explores -omics studies utilising mass spectrometry to investigate the molecular phenotype associated with carbapenem resistance. Whilst the specific mechanisms of carbapenem resistance are well characterised, the resistant phenotype is poorly understood. Understanding how the acquisition of resistance affects cellular physiology and cell metabolism through molecular phenotyping is a necessary step towards detecting resistance by diagnostic means. In addition, this article examines the potential of mass spectrometry for the identification of resistance biomarkers through molecular profiling of bacteria. Developments in mass spectrometry platforms are expanding the biomarker-based diagnostic landscape. Targeted measures, such as high-resolution mass spectrometry coupled with chromatographic separation show considerable promise for the identification of molecular signatures and the development of a rapid diagnostic assay for the detection of carbapenem resistance.

With the advancement of blueberry industrialization, cultivation measures for obtaining high-quality fruits and technologies for obtaining high levels of the main secondary metabolites have become inevitable requirements for further development of the blueberry industry. This study applied different shading treatments and found that the FT1 shading treatment yielded the largest values for the single fruit weight, solid longitudinal diameter and transverse diameter of blueberry fruit as well as the highest solidity-acid ratio and total phenol and vitamin C contents. Moreover, 470 known metabolites were obtained from blueberry fruits. Interestingly, the differentially abundant metabolites related to ABC transporters, pyrimidine metabolism, and purine metabolism pathways were commonly identified from the three comparisons, which indicated that these three metabolic pathways in blueberry fruits are vulnerable to shading treatment. This study provides a theoretical basis for the application of summer shading to improve the quality and antioxidant substances of small berries.