Liquid Chromatography-tandem Mass Spectrometry Research Articles

Antioxidant: Antimycobacterial and Antibiofilm Activities of Acetone Extract and Subfraction Artemisia afra Jacq. ex Willd. Against Mycobacterium smegmatis

Tuberculosis is a worldwide prevalent and recurring disease that contributes significantly to high mortality rates. This study aimed to investigate the antioxidant, anti-mycobacterial, and antibiofilm activities of Artemisia afra acetone crude extract. Methodology: The crude acetone extract was fractionated using column chromatography and characterized by liquid chromatography–mass spectroscopy (LC-MS). A 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assay was used to assess the antioxidant activity. The antimycobacterial activity against Mycobacterium smegmatis was screened using bioautography, broth microdilution, and growth curve assays. Molecular docking was used to predict the possible mechanisms of action of the LC-MS-identified ligands. Crystal violet was used to screen for anti-cell adherence and biofilm inhibition activities. Results: The crude extract scavenged 77% of the free radical at 16 μg/mL. The subfraction had a lower minimum inhibitory concentration (MIC) (0.078 mg/mL) compared to the crude extract (0.313–0.833 mg/mL). The subfraction had a concentration-dependent inhibition effect (>50%) on mycobacterial cell adherence and early biofilms. However, the mature biofilms were resistant. Two propanoate compounds, [(2S)-3-[6-acetyl-4,6-dihydroxy-3-[(1R)-1-hydroxyethyl]tetrahydropyran-2-yl]-2-hydroxy-propyl] (2R)-2-amino-3-(1H-imidazol-5-yl)propanoate and 3-(6-aminopurin-9-yl)propyl 3-(2,4-dioxo-1,3-diazaspiro[4.5]decan-3-yl) propanoate, had binding energies of −5.4 kcal/mol and −6.3 kcal/mol, respectively, against the RNA polymerase binding protein. Conclusions: The results show that A. afra acetone crude extract has antioxidant and antimycobacterial activities that can be improved by fractionation.

A COMPREHENSIVE REVIEW-: TOXICOLOGICAL EFFECT OF COMMON DRUG AND POISON ON HUMAN PHYSIOLOGY AND ANALYTICAL DETECTION TECHNIQUES TO DETECT IN BIOLOGICAL SAMPLES- USING INSTRUMENTATION CHROMATOGRAPHY, BIOSENSORS AND NANOTECHNOLOGY

The study of drugs and Poisons on human physiology is crucial for Understanding their cause and impact on health and developing effective techniques for detection methods. This Research aims to explore the mechanism by which various substances from prescription medication to environmental toxins interact with biological samples or materials. The investigation focuses on the pathophysiology change induced by these agents including alteration in cellular function, disturbance in metabolic pathways and organ specific damage. This studies also focused on the analytical techniques used for detection these substance in biological sample, Instruments used for this such as, GCMS [ Gas chromatography mass spectroscopy ], LCMS [ liquid chromatography mass spectroscopy ] UV, FTIR, HPTLC can be used. Immunoassays are examined for their effectiveness in identifying and quantifying toxic compounds.

Evaluating MIR and NIR Spectroscopy Coupled with Multivariate Analysis for Detection and Quantification of Additives in Tobacco Products.

The detection and quantification of additives in tobacco products are critical for ensuring consumer safety and compliance with regulatory standards. Traditional analytical techniques, like gas chromatography-mass spectrometry (GC-MS), liquid chromatography-mass spectrometry (LC-MS), and others, although effective, suffer from drawbacks, including complex sample preparation, high costs, lengthy analysis times, and the requirement for skilled operators. This study addresses these challenges by evaluating the efficacy of mid-infrared (MIR) spectroscopy and near-IR (NIR) spectroscopy, coupled with multivariate analysis, as potential solutions for the detection and quantification of additives in tobacco products. So, a representative set of tobacco products was selected and spiked with the targeted additives, namely caffeine, menthol, glycerol, and cocoa. Multivariate analysis of MIR and NIR spectra consisted of principal component analysis (PCA), hierarchical clustering analysis (HCA), partial least squares-discriminant analysis (PLS-DA) and soft independent modeling of class analogy (SIMCA) to classify samples based on targeted additives. Based on the unsupervised techniques (PCA and HCA), a distinction could be made between spiked and non-spiked samples for all four targeted additives based on both MIR and NIR spectral data. During supervised analysis, SIMCA achieved 87-100% classification accuracy for the different additives and for both spectroscopic techniques. PLS-DA models showed classification rates of 80% to 100%, also demonstrating robust performance. Regression studies, using PLS, showed that it is possible to effectively estimate the concentration levels of the targeted molecules. The results also highlight the necessity of optimizing data pretreatment for accurate quantification of the target additives. Overall, NIR spectroscopy combined with SIMCA provided the most accurate and robust classification models for all target molecules, indicating that it is the most effective single technique for this type of analysis. MIR, on the other hand, showed the overall best performance for quantitative estimation.

Quantitative analysis of methylmalonic acid in human plasma by LC-MS/MS after derivatization

Methylmalonic acid (MMA) is a reverse biomarker of vitamin B12 that is increasingly utilized in clinical practice. However, its low sensitivity and susceptibility to strong interference from isomer present chromatographic challenges. We have developed a rapid derivatization method for plasma MMA at room temperature, converting it to the corresponding 2,2,2-trifluoroethylamide derivative using N-(3-dimethylaminopropyl)-N’-ethylcarbodiimide hydrochloride (EDC) and 2,2,2-trifluoroethylamine hydrochloride (TFEA). Amidization was completed within 10 min, followed by protein precipitation extraction of the amides with trichloroacetic acid for Liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. This technique notably enhanced the signal-to-noise ratio of MMA in chromatography. The derivatized MMA exhibited excellent linearity within a concentration range of 42.4–2711.9 nmol/L, with a correlation coefficient (R2) of 0.9990. The intraday and interday precision of replicate measurements ranged from 2.4 % to 4.4 % and 2.6 % to 2.8 %, respectively, while the recovery fell between 97.9 % and 100.1 %.

Rapid Convolutional Algorithm for the Discovery of Blueberry Honey Authenticity Markers via Nontargeted LC-MS Analysis.

Bees produce honey through the collection and transformation of nectar, whose botanical origin impacts the taste, nutritional value, and, therefore, the market price of the resulting honey. This phenomenon has led some to mislabel their honey so that it can be sold at a higher price. Metabolomics has been gaining popularity in food authentication, but rapid data mining algorithms are needed to facilitate the discovery of new authenticity markers. A nontargeted high-resolution liquid chromatography-mass spectrometry (HR/LC-MS) analysis of 262 monofloral honey samples, of which 50 were blueberry honey, was performed. Data mining methods were demonstrated for the discovery of binary single-markers (compound was only detected in blueberry honey), threshold single-markers (compound had the highest concentration in blueberry honey), and interval ratio-markers (the ratio of two compounds was within a unique interval in blueberry honey). A novel convolutional algorithm was developed for the discovery of interval ratio-markers, which trained 14× faster and achieved a 0.2 Matthews correlation coefficient (MCC) units higher classification score than existing open-source implementations. The convolutional algorithm also had classification performance similar to that of a brute-force search but trained 1521× faster. A pipeline for shortlisting candidate authenticity markers from the LC-MS spectra that may be suitable for chemical structure identification was also demonstrated and led to the identification of niacin as a blueberry honey threshold single-marker. This work demonstrates an end-to-end approach to mine the honey metabolome for novel authenticity markers and can readily be applied to other types of food and analytical chemistry instruments.

A novel approach utilizing rapid thin-film microextraction method for salivary metabolomics studies in lung cancer diagnosis

This study investigated the potential of targeted salivary metabolomics as a convenient diagnostic tool for lung cancer (LC), utilizing a rapid TFME-based method. It specifically examines TFME blades modified with SiO2 nanoparticles, which were produced using a custom-made coating system. Validation of the metabolite biomarker analysis was performed by these blades using liquid chromatography-tandem mass spectroscopy (LC-MS/MS).The extraction efficiencies of SiO2 nanoparticle/polyacrylonitrile (PAN) composite-coated blades were compared for 18 metabolites. Response surface methodology (RSM) was used to optimize the analysis conditions. Linear calibration plots were obtained for all metabolites at concentrations between 0.025 to 4.0 μg/mL in the presence of internal standard, with correlation coefficients (R2) ranging from 0.9975 to 0.9841. The limit of detection (LOD) and limit of quantitation (LOQ) were in the range of 0.014 to 0.97μg mL−1 and 0.046 to 3.20 μgmL−1, respectively. The %RSD values for all analytes were within the acceptable range (less than 20 %) for the proposed method.The method was applied to the saliva samples of 40 patients with LC and 38 healthy controls. The efficacy of metabolites for LC diagnosis was determined by in silico methods and the results reveal that phenylalanine and purine metabolism metabolites (e.g., hypoxanthine) are of great importance for LC diagnosis. Furthermore, potentially significant biomarker analysis results from the ROC curve data reveal that proline, hypoxanthine, and phenylalanine were identified as potential biomarkers for LC diagnosis.

Minor Cannabinoid Profile of Unregulated Cannabidiol Products.

Background: Although the majority of cannabinoid research has focused on delta-9-tetrahydrocannabinol (Δ9-THC) and cannabidiol (CBD), there is increasing interest in the therapeutic effects of other phytocannabinoid compounds (i.e., minor cannabinoids), as there is little known about their effects or interaction with CBD. The current study objective was to determine the concentrations of 15 minor cannabinoids in unregulated, over-the-counter CBD products. Methods: A cross-section sample of 80 local and national brands of hemp-derived oil products was purchased both online and in local retail outlets in central Kentucky. Epidiolex® was included as a regulated control. Samples from each product were extracted by solvent extraction and quantified by liquid-chromatography tandem mass-spectrometry. The targeted cannabinoids were: cannabidiolic acid (CBDA), cannabidivarin (CBDV), cannabidivarinic acid, Δ9-tetrahydrocannabivarin, Δ9-tetrahydrocannabivarinic acid, Δ9-tetrahydrocannabinolic acid-A, Δ8-tetrahydrocannabinol (Δ8-THC), cannabigerol (CBG), cannabigerolic acid, cannabinol (CBN), cannabinolic acid, cannabicyclol (CBL), cannabicyclolic acid, cannabichromene (CBC) and cannabichromenic acid. Results: Among the unregulated products included in this analysis, the most frequently detected minor cannabinoids were CBDV (100% of samples tested), CBG (77%), CBC (72%), CBN (67%), CBL (67%), and CBDA (51%). Δ8-THC was not detected in any of the products tested. Concentrations of these cannabinoids varied widely from trace concentrations to several mg/mL (e.g., CBDA: 0.006-12.258 mg/mL). Conclusions: These data indicate CBD products often contain minor cannabinoids, although the array and concentrations of these cannabinoids vary widely across products. The concentrations of these minor cannabinoids are largely absent from product labels, leaving consumers uninformed about product contents.

Determination of 4-methylimidazole and 2-acetyl-4-tetrahydroxy-butylimidazole in caramel color and products by liquid chromatography-mass spectrometry

The simultaneous determination of 4-MEI and THI in caramel and products by LC-MS/MS was developed with several advantages of simplicity, selectivity, and high sensitivity. Chromatographic separation was performed using a C18 column (100 × 2.1 mm, 1.7 μm), with a mobile phase consisting of ammonium formate pH = 4 and acetonitrile containing 0.1% formic acid employing a gradient elution mode. The analytes were detected using an MS/MS double mass spectrometer with an ESI+ ionization source. Samples were cleaned and enriched on a SPE MCX column. Method validaion resulted in a linear range of 5.0 - 500 ppb for 4-MEI, and 1.0 - 500 for THI, with LODs of 0.30 g/kg for THI and 1.5 μg/kg for 4-MEI, and LOQs of 1 μg/kg for THI and 5 μg/kg for 4-MEI. Repeatability and reproducibility for 4-MEI ranged from 2.9% to 9.1% and 2.9% to 11.8%, respectively, and for THI from 3.5% to 9.4% and 4.8% to 11.5%, respectively. Recovery rates for with 4-MEI and THI met AOAC's requirements, ranging from 82.7% to 106.4% and 87.2% to 109.7%, respectively. Application of the analytical method for 24 market products, including caramel, beverages, condiments, and cakes, showed that the 4-MEI and THI concentrations in consumer products were within the permissible limits, while pure caramel samples exceeded the permissible limits for THI concentrations.

Templates effects on the morphological, optical, and photocatalytic properties of ZnO nanostructures synthesized via precipitation method

A simple and effective method was used to synthesize zinc oxide (ZnO) nanoparticles in the presence of chitosan (Cs) and Pluronic 123 (P) as templates. A comparative study was then conducted to evaluate the optical, morphological, and photocatalytic properties of the resulting materials. The synthesized nanoparticles were characterized using various techniques, including XRD, FTIR, DRS, EDX, SEM, and N2 adsorption–desorption. Additionally, density functional theory (DFT) calculations were employed to explore the electronic properties of the nanoparticles. The results demonstrated that the templates significantly influenced in the morphology of materials. Additionally, ZnO-Cs showed a lower band gap and the highest specific surface area (20.57 m2/g). The samples showed good stability and significant photocatalytic activity under UV-B radiation at the natural solution pH (without adjustment). The degradation of methylene blue (MB) was confirmed by liquid chromatography-mass spectrometry (LC-MS) analysis. Furthermore, the mechanism of photocatalytic degradation of the organic dye was investigated using conceptual DFT analysis and validated through comparison with previously reported experimental data.

Mutual Interactions of Silymarin and Colon Microbiota in Healthy Young and Healthy Elder Subjects.

This multi-omic study investigates the bidirectional interactions between gut microbiota and silymarin metabolism, highlighting the differential effects across various age groups. Silymarin, the extract from Silybum marianum (milk thistle), is commonly used for its hepatoprotective effects. An in vitro fermentation colon model was used with microbiota from 20 stool samples obtained from healthy donors divided into two age groups. A combination of three analytical advanced techniques, namely proton nuclear magnetic resonance (1H NMR), next-generation sequencing (NGS), and liquid chromatography-mass spectrometry (LC-MS) was used to determine silymarin microbial metabolites over 24h, overall metabolome, and microbiota composition. Silymarin at a low diet-relevant dose of 50µgmL-1 significantly altered gut microbiota metabolism, reducing short-chain fatty acid (acetate, butyrate, propionate) production, glucose utilization, and increasing alpha-diversity. Notably, the study reveals age-related differences in silymarin catabolism. Healthy elderly donors (70-80 years) exhibited a significant increase in a specific catabolite associated with Oscillibacter sp., whereas healthy young donors (12-45 years) showed a faster breakdown of silymarin components, particularly isosilybin B, which is associated with higher abundance of Faecalibacterium and Erysipelotrichaceae UCG-003. This study provides insights into microbiome functionality in metabolizing dietary flavonolignans, highlighting implications for age-specific nutritional strategies, and advancing our understanding of dietary (poly)phenol metabolism.

Mediating effect of oxidative stress on blood pressure elevation in workers exposed to low concentrations of benzene, toluene, and xylene (BTX).

To investigate the mediating effect of oxidative stress on the relationships between low-concentration benzene, toluene, and xylene (BTX) exposure and blood pressure in workers. A cross-sectional study involving 841 workers from a petroleum refining enterprise in Hainan, China, was conducted. Among the workers, 615 workers were exposed to low-concentration BTX, and 216 workers were in the control group. S-phenylmercapturic acid (S-PMA), hippuric acid (HA), and methyl hippuric acid (MHA, including the three isomers 2-MHA, 3-MHA, and 4-MHA) were measured in the urine of workers via high-performance liquid chromatography‒tandem triple quadrupole mass spectrometry to assess the internal BTX burden. Oxidative stress markers, blood pressure, and their correlations were analysed in both the exposed and control groups of workers. Mediation analysis was used to investigate the potential role of oxidative stress in the relationship between BTX exposure and blood pressure. The concentrations of BTX at the sampling points in the enterprise were all below the limits stipulated in China's national occupational health criteria: occupational exposure limits for hazardous agents. With respect to the internal burden of BTX, the concentrations of the benzene metabolite S-PMA, the toluene metabolite HA, and the xylene metabolites 3-MHA and 4-MHA in the urine samples in the exposure group were greater than those in the control group (P < 0.05). The correlation analysis results revealed that the concentration of the benzene metabolite S-PMA in workers' urine was positively correlated with diastolic blood pressure (DBP) (r = 0.265, P < 0.05). Compared with those in the control group, DBP was greater (β = 1.363, 95% CI 0.088 -2.639), serum superoxide dismutase (SOD) activity was lower (β = - 0.037, 95% CI - 0.060 to - 0.013), and the serum malondialdehyde (MDA) concentration was greater (β = 0.066, 95% CI 0.022-0.110) in the exposure group. Partial correlation analysis revealed a positive correlation between DBP and MDA (rs = 0.115, P < 0.01). The results of the mediation analysis indicated that MDA was a complete mediator between low BTX exposure and DBP (P < 0.05). Occupational exposure to low concentrations of BTX elevates blood pressure and oxidative stress among workers. A positive correlation between DBP and MDA was observed, with MDA acting as a complete mediator between low-concentration BTX exposure and DBP elevation.

Pharmacokinetics and bioequivalence of ezetimibe tablet in healthy Chinese subjects under fasting and fed conditions.

The purpose of this study is to evaluate the pharmacokinetics (PK) parameters of an ezetimibe 10 mg (test drug) and assess its bioequivalence to the branded reference product in healthy Chinese subjects under fasting and fed conditions. A single-center, randomized, open-label, four-period, two-sequence, full replicate crossover study was conducted in 88 healthy Chinese subjects under fasting or fed conditions. Subjects received a single oral dose of 10 mg ezetimibe tablet as test or reference formulation. There was a minimum 14-day washout period between each dose. Blood samples were collected at prescribed time intervals, the plasma concentration of free ezetimibe and total ezetimibe (ezetimibe + ezetimibe glucuronide) was determined by a validated ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method. Pharmacokinetik and bioavailability parameters were estimated via non-compartmental methods. Adverse events were also recorded. 40 and 48 eligible healthy subjects were enrolled in the fasted and fed study. Under fasting state, total ezetimibe with 90% confidence intervals (CIs) of Cmax, AUC0-t, and AUC0-∞ were 87.17% (81.99 - 92.66%), 95.98% (92.38-99.72%), and 96.04% (91.37 - 100.95%), respectively. Under fed state, total ezetimibe with 90% confidence intervals (CIs) of Cmax, AUC0-t, and AUC0-∞ were 98.71% (90.11 - 108.13%), 98.32% (94.71 - 102.06%), and 97.90% (92.68 - 103.42%), respectively. The 90% CIs of the ratio of geometric means (GMRs) of Cmax, AUC0-t, AUC0-∞ of the test and reference formulation in both fasting and fed conditions fell within the conventional bioequivalence criteria of 0.80 - 1.25. No severe adverse events were observed. The test and reference 10-mg ezetimibe tablets were bioequivalent under fasting and fed conditions in Chinese subjects. Both preparations showed good safety and tolerability.

Metabolomics-Based Machine Learning for Predicting Mortality: Unveiling Multisystem Impacts on Health.

Reliable predictors of long-term all-cause mortality are needed for middle-aged and older populations. Previous metabolomics mortality studies have limitations: a low number of participants and metabolites measured, measurements mainly using nuclear magnetic spectroscopy, and the use only of conventional statistical methods. To overcome these challenges, we applied liquid chromatography-tandem mass spectrometry and measured >1000 metabolites in the METSIM study including 10,197 men. We applied the machine learning approach together with conventional statistical methods to identify metabolites associated with all-cause mortality. The three independent machine learning methods (logistic regression, XGBoost, and Welch's t-test) identified 32 metabolites having the most impactful associations with all-cause mortality (25 increasing and 7 decreasing the risk). From these metabolites, 20 were novel and encompassed various metabolic pathways, impacting the cardiovascular, renal, respiratory, endocrine, and central nervous systems. In the Cox regression analyses (hazard ratios and their 95% confidence intervals), clinical and laboratory risk factors increased the risk of all-cause mortality by 1.76 (1.60-1.94), the 25 metabolites by 1.89 (1.68-2.12), and clinical and laboratory risk factors combined with the 25 metabolites by 2.00 (1.81-2.22). In our study, the main causes of death were cancers (28%) and cardiovascular diseases (25%). We did not identify any metabolites associated with cancer but found 13 metabolites associated with an increased risk of cardiovascular diseases. Our study reports several novel metabolites associated with an increased risk of mortality and shows that these 25 metabolites improved the prediction of all-cause mortality beyond and above clinical and laboratory measurements.

Roseoside Is a Bioactive Compound in Kirengeshoma koreana Nakai Extract with Potent In Vitro Antiviral Activity Against Hepatitis C Virus.

Hepatitis C virus (HCV) is a pathogen that causes cirrhosis and hepatocellular carcinoma through chronic hepatitis C. This study focused on the anti-HCV activity of a 70% ethanol extract of Kirengeshoma koreana Nakai (KKE) and its bioactive chemical constituent(s). The KKE and its n-butanol (n-BuOH) fraction induced a significant reduction in HCV RNA levels without inducing cytotoxicity. A high-performance liquid chromatography-mass spectrometry (HPLC-MS) analysis revealed the presence of roseoside in the n-butanol fraction of the KKE, which inhibited HCV RNA replication in a concentration- and time-dependent manner without exerting cytotoxicity. Consistent with in silico molecular docking analysis data, roseoside targets and inhibits HCV NS5A/B replicase. Collectively, our findings demonstrate that roseoside is a chemical constituent in KKE that interferes with HCV replication by targeting NS5A/B replicase.

Comparison of the potential risk from arsenic exposure when eating fish grown in natural and artificial conditions, using the example of rainbow trout

Introduction. Due to the increasing share of fish and fish products in the human diet, hygienic problems are also increasing, especially with the growing of aquaculture sector. The task of determining the level of arsenic toxicity is becoming extremely important. Although the toxicity mechanisms of inorganic arsenic are generally well understood, the impact of speciation of its other (organic) compounds on the likelihood of carcinogenic and non-carcinogenic effects has been largely unexplored. Material and methods. The objects of study were samples of fillet and caviar of salmon fish – rainbow trout (wild and aquaculture). The quantitative determination of arsenic-containing substances was carried out using high-performance liquid chromatography-mass spectrometry with inductively coupled plasma. The samples were prepared using microwave methods. The risk level was calculated based on recommendations R 2.1.10.3968–23. Results. As the result of this work the information about concentration of arsenic (organic and inorganic compounds) in fillets and caviar of fish from the salmon family - rainbow trout was shown. It has been established that the content of inorganic and organic arsenic compounds practically does not differ, depending of the habitat of trout. The levels of carcinogenic and non-carcinogenic risk of inorganic arsenic were calculated. Limitations. Determination of arsenic concentration was carried out in rainbow trout, which had been grown in natural and artificial conditions. Conclusion. It has been established that inorganic arsenic makes the greatest contribution to the health risk. However, the magnitude of the risk does not exceed the acceptable sanitary and hygienic standards, while the conditions for growing fish have practically no effect on these values.

Long-chain polyunsaturated fatty acid-containing phosphatidylcholines predict survival rate in patients after heart failure

BackgroundHeart failure (HF) is becoming an increasingly prevalent issue, particularly among the elderly population. Lipids are closely associated with cardiovascular disease (CVD) pathology. Lipidomics as a comprehensive profiling tool is showing to be promising in the prediction of events and mortality due to CVD as well as identifying novel biomarkers. Materials and methodsIn this study, eicosanoids and lipid profiles were measured in order to predict survival in patients with de novo or acute decompensated HF. Our study included 50 patients (16 females, mean age 73 years and 34 males, mean age 71 years) with de novo or acute decompensated chronic HF with a median follow-up of 7 months. Lipids were semiquantified using targeted lipidomic liquid chromatography-mass spectrometry (LC-MS/MS) analysis. Eicosanoid concentrations were determined using a commercially available sandwich ELISA assay. ResultsFrom 736 lipids and 3 eicosanoids, 39 significant lipids were selected (by using the Mann-Whitney U test after Benjamini-Hochberg correction) with the highest number of representatives belonging to the polyunsaturated (PUFA) phosphatidylcholines (PC). PC 42:10 (p = 1.44 × 10−4) was found to be the most statistically significantly elevated in the surviving group with receiver operating characteristics of AUC = 0.84 (p = 3.24 × 10−7). A multivariate supervised discriminant analysis based on the aforementioned lipid panel enabled the classification of the groups of surviving and non-surviving patients with 90 % accuracy. ConclusionsIn the present study we describe a trend in PUFA esterified in PC that were systematically increased in surviving patients with HF. This trend in low-abundant and rarely identified PUFA PC (mainly very long chain PUFA containing PC such as PC 42:10 or PC 40:9 containing FA 22:6, FA 20:5 and FA 20:4) suggests candidate biomarkers.

Bioequivalence Analysis of Ondansetron Hydrochloride Tablets in Healthy Chinese Subjects: A Randomized, Open-Label, Two-Period Crossover Phase I Study.

Ondansetron is a highly selective 5-HT3 receptor antagonist that alleviates nausea and vomiting. Bioequivalence evaluation ensures that the efficacy of generic drugs is consistent with that of the original drug. The objective of this study was to evaluate the bioequivalence of ondansetron hydrochloride (HCl) tablets taken in single doses under fasting and postprandial conditions in healthy subjects. In this randomized, open-label, two-cycle, crossover phase I study, liquid chromatography‒tandem mass spectrometry (LC‒MS/MS) was used to determine the ondansetron concentration in dipotassium-ethylenediaminetetraacetate (K2-EDTA) plasma after the subjects received a single 8 mg of ondansetron and reference formulation. Twenty-six healthy subjects received one tablet of ondansetron under fasting conditions and 28 subjects received one under postprandial conditions. Bioequivalence was established if the 90% confidence interval (CI) was 80.00-125.00%. The pharmacokinetic parameters were calculated via WinNonLin 8.1 software and the bioequivalence data were evaluated via Phoenix WinNonlin 8.1 statistics software. The geometric mean ratio (GMR) of the maximum observed concentration (Cmax), the area under the plasma concentration‒time curve (AUC) from time zero to the last sampling time (AUC0-t), and the AUC from time zero to infinity (AUC0-∞) from the test/reference formulation under fasting conditions were 90.50, 90.43, and 90.25, respectively. The 90% CIs were 83.75-97.79, 82.64-98.95, and 82.25-99.03, respectively. The GMRs of Cmax, AUC0-t, and AUC0-∞ after a high-fat meal were 96.85, 93.57, and 93.77, respectively; the 90% CIs were 88.43-106.07, 87.35-100.24, and 87.35-100.68, respectively. The test and reference formulations of ondansetron HCl have bioequivalence for healthy adult subjects under fasting and postprandial conditions.

A Trp-574-Leu mutation in acetolactate synthase confers imazamox resistance in barnyardgrass (Echinochloa crus-galli) from China

Abstract Barnyardgrass [Echinochloa crus-galli (L.) P. Beauv.] is increasingly infesting imidazolinone-tolerant (IMI-T) rice fields in China, imazamox resistance of E. crus-galli has become the major concern for weed management in IMI-T rice fields. In this study, the susceptible population JLGY-3 (S) and the suspected resistant population JHXY-2 (R) collected from IMI-T rice fields were used as research subjects. When treated with imazamox, JHXY-2 (R) population showed a high level of herbicide resistance with a resistance index (RI) of 31.2. JHXY-2 (R) was cross-resistant to all five acetolactate synthase (ALS) inhibitors from different chemical families, but sensitive to herbicides inhibiting acetyl-CoA carboxylase (ACCase). In order to understand the reason why JHXY-2 (R) was resistant to imazamox, we performed experiments to characterize potential TSR and NTSR mechanisms. A trp-574-leu amino acid mutation in ALS and low imazamox ALS sensitivity were the main mechanism underlying imazamox resistance in this JHXY-2 (R) population. There was no significant difference in ALS gene expression and ALS protein abundance between R and S populations. High-performance liquid chromatography-tandem mass spectrometry analysis showed enhanced metabolism of imazamox in JHXY-2 (R), which was in contrast to the results of pretreatment with a metabolic enzyme inhibitor. Treatments with the P450/GST inhibitors did not alter the resistance level of JHXY-2 (R) against imazamox. To further clarify the NTSR mechanism of JHXY-2 (R), transcriptome sequencing showed that there was almost no significant difference in the expression of P450 and GST metabolic enzyme genes between R and S populations, and only GST-U1 showed a significant induction in R population. In conclusion, amino acid mutation and higher enzyme activity of ALS are the main causes of imazamox resistance in JHXY-2 (R). However, given the differences in imazamox residues in the leaves of the E. crus-galli, there may still be undetectable NTSR that are causing imazamox resistance in the R population.

Rapid and Effective Determination of Ethyl Glucuronide in Hair by Micro Extraction by Packed Sorbent (MEPS) and LC-MS/MS.

Ethyl glucuronide (EtG) in hair is a reliable biomarker of alcohol consumption habits. Due to its small concentration incorporated into hair, analytical methods sensitive enough to reliably quantify EtG in this matrix are required. Sample preparation is critical in hair analysis, especially for EtG, for which extraction efficiency and matrix effect can strongly influence the results; furthermore, miniaturized methods are sought, to reduce solvent use and times of sample preparation. A micro extraction by packed sorbent (MEPS) procedure coupled to a high-performance liquid chromatography-tandem mass spectrometry method was developed and validated for quantitation of EtG in human hair samples. Fifty milligrams of hair samples were cut into snippets and extracted in water. The cleanup of the extract was carried out by using a MEPS syringe packed with anion exchange sorbent (SAX); all parameters for conditioning, washing, loading and eluting steps were optimized and the eluted aqueous volume was directly injected in the LC-MS/MS system operating in the negative ionization mode. The method was fully validated assessing LOD, LOQ, calibration curve, repeatability, accuracy, matrix effect and carryover. The method was subsequently applied to QCs and authentic hair samples. The developed MEPS method is quick and effective, with low solvent purchase and discard costs, allowing the differentiation between social drinkers and chronic excessive alcohol consumers, according to the cut-offs established by the Society of Hair Testing (SoHT).

Proteomic identification of apoplastic proteins from rice, wheat, and barley after Magnaporthe oryzae infection

The fungal pathogen Magnaporthe oryzae causes devastating blast disease in various cereals, including rice (Oryza sativa), wheat (Triticum aestivum), maize (Zea mays), and barley (Hordeum vulgare). Despite previous reports on fungal host specificity, the mechanisms underlying differential host infection strategies remain unclear. This study aimed to identify differentially abundant proteins (DAPs) in the apoplast of rice, barley, and wheat following infection with two M. oryzae pathovars using liquid chromatography-tandem mass spectrometry (LC–MS/MS). LC–MS/MS analysis revealed an enrichment of both M. oryzae and host proteins in the apoplast during the compatible reaction compared to the incompatible reaction. DAPs from M. oryzae involved in the host interaction included secreted extracellular enzymes (e.g., hydrolases), which were significantly increased in the M. oryzae Oryzae (MoO)-infected rice apoplast. Among host proteins, the proportion of protein-modifying enzymes increased in the M. oryzae Triticum (MoT)-infected rice and MoO-infected wheat apoplastic fluids, particularly rice glycosidases, peroxidases, and serine proteases, as well as wheat serine proteases. Furthermore, DAPs from MoL-infected rice were enriched in carbohydrate metabolism, suggesting that carbohydrate metabolism-related proteins may play a vital role in rice resistance to MoL. Additionally, protein-modifying and cytoskeletal proteins, as well as stress-responsive proteins, were enriched in the MoO-infected wheat apoplastic fluid. Finally, DAPs from both MoO- and MoL-infected barley were enriched in hydrogen peroxide catabolism, suggesting that peroxidases may be vital for barley resistance to M. oryzae. The identification of DAPs from both M. oryzae strains and the three host plants offers valuable insights into the host specificity mechanisms of M. oryzae in cereal crops.