Search

Rationale: To uphold the integrity of horseracing and equestrian sports, it is critical for an equine doping control laboratory to develop a comprehensive screening method to cover a wide range of target substances at the required detection levels in equine urine. Methods: The procedure involved the enzymatic hydrolysis of 3 mL urine samples followed by solid‐phase extraction using HF Bond Elut C18 cartridge. The resulting extracts were then separated on a C18 reversed‐phase column and analyzed using liquid chromatography/high‐resolution mass spectrometry (LC/HRMS) in both electrospray ionization positive and negative modes in two separate injections. The analytical data were obtained in full scan and product ion scan (PIS) modes in an 11 min LC run. Results: The method can detect 1011 compounds (in both positive and negative ion modes). Over 95% of the target compounds have limits of detections (LODs) ≤10 ng/mL, and more than 50% of the LODs are ≤0.5 ng/mL. The lowest LOD can reach down to 0.01 ng/mL. The applicability of the method was demonstrated by the successful detection of prohibited substances in overseas and domestic equine urine samples. Conclusions: We have successfully developed a regular screening method for equine urine samples that can detect more than 1000 compounds at sub‐ppb levels in both positive and negative ion modes with full scan and PIS using LC/HRMS. Furthermore, this method can theoretically be expanded to accommodate an unlimited number of prohibited substances in full‐scan mode. [ABSTRACT FROM AUTHOR]

Rationale: Rivaroxaban is an anticoagulant prescribed to patients who are at risk of medical conditions such as deep‐vein thrombosis, pulmonary embolisms, and strokes caused by blood clots. The administration of this drug is monitored to adjust the dosage and evaluate patients' blood concentration. Rapid quantification of this drug in plasma could make it possible to ensure that the dose present in the blood of patients does not represent a danger for the medical intervention to be carried out. Methods: Liquid chromatography–tandem mass spectrometry is usually employed to quantify rivaroxaban in blood, plasma, and serum. Here, an alternative method of analysis based on laser diode thermal desorption–triple quadrupole mass spectrometry (LDTD‐QqQMS) was developed and comprehensively validated. This new method allows the quantification of rivaroxaban in less than 13 s from sample to sample. The extraction of rivaroxaban in human serum was done by a salting‐out liquid–liquid extraction with acetonitrile and a saturated sodium chloride solution. Results: The proposed method allows the quantification of rivaroxaban in less than 13 s from sample to sample. During validation, all criteria were respected. The accuracy was <15% of the nominal value, the precision was <15%CV, and the recovery was ≥89.9%. There were no observed carryover or matrix effects. Analysis of the extracted samples established the stability of dry (24 h) and wet samples (1 week) when samples cannot be analyzed immediately, a considerable advantage in a clinical setting. Conclusions: This method improves sample throughput by more than 1200% compared to liquid chromatography–tandem mass spectrometry methods of analysis of rivaroxaban and decreases analysis costs by reducing solvent consumption and instrument time. [ABSTRACT FROM AUTHOR]

This article presents a study on the use of urinary guanidino compounds (GCs) and ureido compounds (UCs) as biomarkers for cardiac surgery-associated acute kidney injury (CSA-AKI). The study utilized a benzylic rearrangement reaction and high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) to analyze the concentrations of GCs/UCs in urine samples from patients with CSA-AKI at different stages. The findings suggest that certain GC/UC metabolites show significant changes in concentration during CSA-AKI and could potentially serve as biomarkers for different stages of AKI. This research provides valuable resources and new therapeutic targets for further study on CSA-AKI. [Extracted from the article]

Rationale: Lomerizine (LMZ) is an antimigraine drug that works as a calcium channel blocker and has selective effects on the central nervous system. It is metabolized into trimetazidine (TMZ), which is a prohibited substance owing to its performance‐enhancing effects in both human and animal sports. Effective doping control measures are imperative to distinguish the source of TMZ in samples to ensure integrity and fairness of the sport, therefore a comprehensive analysis of LMZ metabolites is essential to identify potential biomarkers in camel urine for effective doping control. Methods: Camel urine samples were collected from four healthy animals following a single oral administration of LMZ at a dosage of 1 mg/kg body weight. In vitro studies were conducted using homogenized camel liver samples. Lomerizine and its metabolites were extracted using solid‐phase extraction and analyzed with a Thermo Fisher Orbitrap Exploris liquid chromatography mass spectrometry system. The acquired data was processed with the Compound Discoverer software. Results: The study conducted a comprehensive analysis of LMZ metabolites in camels and identified 10 phase I and one phase II metabolites. The primary pathway for the formation of phase I metabolites was de‐alkylation, while phase II metabolite was formed through alkylation of the parent drug. The study provided valuable insights into the unique metabolic pathways of LMZ in camels under specific experimental conditions. Conclusion: The developed method enables the detection and characterization of LMZ and its metabolites in camels. The identified metabolites has the potential to act as marker metabolites for the distinctive detection of LMZ in camel urine to ensure efficient analytical strategies for routine doping control applications. [ABSTRACT FROM AUTHOR]

Introduction Objectives Methods Results Conclusion Acute lymphoblastic leukaemia (ALL) is the most common type of childhood leukaemia with effective chemotherapeutic treatment. However, obesity has been associated with higher ALL chemoresistance rates and lower event‐free survival rates. The molecular mechanism of how obesity promotes chemotherapy resistance is not well delineated.This study evaluated the effect of adipocyte maturation on sequestration and metabolism of chemotherapeutic drug daunorubicin (DNR).Using targeted LC‐MS/MS multi‐analyte assay, DNR sequestration and metabolism were studied in human preadipocyte and adipocyte cell lines, where expressions of DNR‐metabolizing enzymes aldo‐keto reductases (AKR) and carbonyl reductases (CBR) were also evaluated. In addition, to identify the most DNR‐metabolizing AKR/CBR isoforms, recombinant human AKR and CBR enzymes were subject to DNR metabolism. The results were further validated by AKR‐, CBR‐specific inhibitors.This report shows that adipocyte maturation upregulates expressions of AKR and CBR enzymes (by 4‐ to 60‐ folds, p < .05), which is positively associated with enhanced sequestration and metabolism of DNR in adipocytes compared to preadipocytes (by ~30%, p < .05). In particular, adipocyte maturation upregulates AKR1C3 and CBR1, which are the predominate metabolic enzyme isoforms responsible for DNR biotransformation to its metabolites.Fat is an expandable tissue that can sequester and detoxify DNR when stimulated by obesity, likely through the upregulation of DNR‐metabolizing enzymes AKR1C3 and CBR1. Our data partially explains why obese ALL patients may be more likely to become chemoresistant towards DNR, and provides evidence for potential clinical investigation targeting obesity to reduce DNR chemoresistance. [ABSTRACT FROM AUTHOR]

This document provides concise summaries of several articles and research studies related to dermatology and contact allergies. The topics covered include non-compliance with nickel regulations, the association between atopic dermatitis and multimorbidity, contact sensitization to rubber additives, the long-term effectiveness of dupilumab treatment for atopic dermatitis, co-sensitizations and cross-reactivities to textile dyes, propolis sensitization and impurities, and various studies on contact allergies and patch testing. These studies offer valuable insights into the prevalence, causes, and treatment of dermatological conditions and contact allergies. [Extracted from the article]

A high‐fat diet (HFD) is one of the main causes of obesity and metabolic diseases. The liver is particularly affected by HFD causing metabolic dysfunction associated with fatty liver disease. Therefore, different strategies are used to mitigate the negative effects of HFD. This study aimed to assess the protective effects of walnut extract against HFD‐induced toxicity in mice. The mice were fed HFD and walnut extract alone or in combination. The walnut extract was analyzed for composition using high‐performance liquid chromatography with a diode array detector (HPLC‐DAD) and ultra‐high‐performance liquid chromatography with mass spectrometry (UHPLC–MS/MS). Serum lipid profile; liver histology; hepatic antioxidants such as catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GSH‐Px), lipid peroxidation (TBARS), and reduced glutathione (GSH); inflammatory markers like IL‐6 and TNF‐α; and phospholipids were determined. Results showed that phenolic acids, epicatechin, catechin, benzaldehyde, and juglone were the main constituents in the extract. The HFD group showed increased hepatic fat accumulation as evidenced by biochemical and histopathological examinations compared to the control animals. The HFD group mice also showed increased body and cardiac weights, modified lipid profiles, decreased antioxidant status, and increased levels of hepatic inflammatory markers. The weights of the body and heart, lipid profiles, antioxidant contents (CAT, SOD, GSH‐Px, TBARS, and GSH), and pro‐inflammatory cytokines (IL‐6 and TNF‐α) were all normalized by consuming walnut extract. Similarly, the HFD group had significantly high amounts of hepatic lipase, phospholipid, and lysophospholipid levels, which were improved by walnut extract. In conclusion, walnut extract has been shown to play a unique role in promoting the recovery of liver damage caused by a high‐fat diet. [ABSTRACT FROM AUTHOR]

A variety of LSD analogs have emerged in recent years with dual purposes of avoiding prosecution from possession while providing new options for those willing to experiment with hallucinogenic drugs. In this study, a previously published automated sample preparation method for LSD and its primary metabolite (OH‐LSD) was utilized to extract LSD, OH‐LSD, and nine LSD analogs from urine. The liquid chromatography tandem mass spectrometry (LC–MS/MS) method was modified from the previously published LC conditions to utilize a different analytical column and gradient elution program. Mobile phases of 10 mM ammonium formate with 0.1% formic acid in deionized water (mobile phase A) and 0.1% formic acid in methanol (mobile phase B) were employed. The method was validated to ANSI/ASB Standard 036 with a 0.1 ng/mL limit of detection for all analytes and was utilized for the analysis of 325 urine specimens. Although no LSD analogs were observed in the samples analyzed, this validated method was demonstrated to be suitable for the analysis of these compounds in laboratories seeking to expand their testing scope. Automated sample preparation allows for the efficient analysis of these analytically challenging compounds with minimal manual handling. Additionally, there was no increased analytical time burden when the LC column and gradient were modified to target nine additional analytes. Detection may improve as new reference standards are developed to allow laboratories to focus on the metabolic products of these analogs. For now, this validated procedure can assist with the routine analysis and surveillance of these emerging substances. [ABSTRACT FROM AUTHOR]

Background: 6‐Nitrodopamine (6‐ND) is a novel endogenous catecholamine that has a potent relaxant action on vascular smooth muscle in vitro. Objectives: To evaluate the basal release of 6‐ND and noradrenaline from rabbit‐isolated corpus cavernosum (RbCC) and its relaxing action on this tissue. Methods: Rabbit corpus cavernosa were dissected and suspended in a 5‐mL organ bath containing oxygenated Krebs‐Henseleit's solution. 6‐ND and noradrenaline release was quantified by liquid chromatography coupled to tandem mass spectrometry. The relaxant activity of 6‐ND was assessed in RbCC strips pre‐contracted with endothelin‐1 (10 nM). Results: Rabbit corpus cavernosum presented basal release of both 6‐ND (2.9 ± 0.8 ng/mL, n = 12) and noradrenaline (1.7 ± 1.3 ng/mL, n = 12). The 6‐ND release was reduced by pre‐treatment with Nω‐nitro‐l‐arginine methyl ester (l‐NAME) (100 µM), whereas that of noradrenaline was unaffected. Tetrodotoxin (TTX, 1 µM) abolished the noradrenaline release but had no effect on 6‐ND release, indicating a non‐neurogenic origin for 6‐ND. 6‐ND and the selective dopamine D2‐agonist L‐741,626 caused concentration‐dependent RbCC relaxations (pEC50 of 11 ± 0.15 and 11.15 ± 0.28, respectively). Pre‐treatment with either l‐NAME or the soluble guanylate cyclase inhibitor 1H‐[1,2,4] oxadiazolo[4,3‐a]quinoxalin‐1‐on (ODQ) (100 µM) caused a rightward shift of the concentration–response curve to 6‐ND, without affecting the L‐741,626 responses. In TTX (100 nM)‐pre‐treated preparations, neither l‐NAME nor ODQ shifted the 6‐ND concentration–response curve. Dopamine, noradrenaline, and adrenaline caused concentration‐dependent RbCC contractions. Pre‐incubation with 6‐ND concentration‐dependently inhibited the dopamine‐induced contractions, without affecting those induced by either noradrenaline or adrenaline. Discussion and conclusion: 6‐Nitrodopamine is the most potent endogenous relaxant agent in RbCC ever described and represents a novel mechanism by which NO causes corpus cavernosum smooth muscle relaxation. The finding that 6‐ND acts as a truly selective dopamine D2‐receptor antagonist indicates that the balance of dopamine and 6‐ND release/synthesis may be the main mechanism that modulates corpus cavernosum smooth muscle tonus in vivo. [ABSTRACT FROM AUTHOR]

Aim: To analyse the association between serum bile acid (BA) profile and heart failure (HF) with preserved ejection fraction (HFpEF) in patients with metabolic dysfunction‐associated fatty liver disease (MAFLD). Methods: We enrolled 163 individuals with biopsy‐proven MAFLD undergoing transthoracic echocardiography for any indication. HFpEF was defined as left ventricular ejection fraction >50% with at least one echocardiographic feature of HF (left ventricular diastolic dysfunction, abnormal left atrial size) and at least one HF sign or symptom. Serum levels of 38 BAs were analysed using ultra‐performance liquid chromatography coupled with tandem mass spectrometry. Results: Among the 163 patients enrolled (mean age 47.0 ± 12.8 years, 39.3% female), 52 (31.9%) and 43 (26.4%) met the HFpEF and pre‐HFpEF criteria, and 38 serum BAs were detected. Serum ursodeoxycholic acid (UDCA) and hyocholic acid (HCA) species were lower in patients with HFpEF and achieved statistical significance after correction for multiple comparisons. Furthermore, decreases in glycoursodeoxycholic acid and tauroursodeoxycholic acid were associated with HF status. Conclusions: In this exploratory study, specific UDCA and HCA species were associated with HFpEF status in adults with biopsy‐confirmed MAFLD. [ABSTRACT FROM AUTHOR]

In food analysis, conventional one‐dimensional liquid chromatography methods sometimes lack sufficient separation power due to the complexity and heterogeneity of the analyzed matrices. Therefore, the use of two‐dimensional liquid chromatography (2D‐LC) turns out to be a powerful tool to consider, especially when coupled to mass spectrometry (MS). This review presents the most remarkable 2D‐LC–MS food applications reported in the last 10 years, including a critical discussion of the multiple approaches, modulation strategies as well as the importance of the optimization of the different analytical aspects that will condition the 2D‐LC–MS performance. The presence of contaminants in food (food safety), the food quality, and authenticity or the relationship between the beneficial effects of food and human health are some of the fields in which most of the 2D‐LC–MS applications are mainly focused. Both heart‐cutting and comprehensive applications are described and discussed in this review, highlighting the potential of 2D‐LC–MS for the analysis of such complex samples. [ABSTRACT FROM AUTHOR]

Epigenetic modifications are closely related to certain disorders of the organism, including the development of tumors. One of the main epigenetic modifications is the methylation of DNA cytosines, 5‐methyl‐2′‐deoxycycytidine. Furthermore, 5‐mdC can be oxidized to form three new modifications, 5‐(hydroxymethyl)‐2′‐deoxycytidine, 5‐formyl‐2′‐deoxycytidine, and 5‐carboxy‐2′‐deoxycytidine. The coupling of liquid chromatography with tandem mass spectrometry has been widely used for the total determination of methylated DNA cytosines in samples of biological and clinical interest. These methods are based on the measurement of the free compounds (e.g., urine) or after complete hydrolysis of the DNA (e.g., tissues) followed by a preconcentration, derivatization, and/or clean‐up step. This review highlights the main advances in the quantification of modified nucleotides and nucleosides by isotope dilution using isotopically labeled analogs combined with liquid or gas chromatography coupled to mass spectrometry reported in the last 20 years. The different possible sources of labeled compounds are indicated. Special emphasis has been placed on the different types of chromatography commonly used (reverse phase and hydrophilic interaction liquid chromatography) and the derivatization methods developed to enhance chromatographic resolution and ionization efficiency. We have also revised the application of bidimensional chromatography and indicated significant biological and clinical applications of these determinations. [ABSTRACT FROM AUTHOR]

Copyright of Nachrichten aus der Chemie is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Rationale: This study used proteomics‐based data‐independent acquisition (DIA) technology with the aim of screening for differential expression proteins in type I gastric neuroendocrine neoplasm (g‐NEN). Methods: Differential expression proteins in type I g‐NEN and peritumoral tissues were screened using DIA with liquid chromatography/tandem mass spectrometry (DIA‐LC/MS/MS). The identified proteins were then functionally analysed using bioinformatics methods. We selected the three most highly expressed proteins, combined with patients' clinical data, for prognostic analysis. Results: Compared with peritumoral tissues, 224 proteins were up‐regulated, and 70 were down‐regulated. The most significantly enriched biological processes and pathways were vacuolar proton‐transporting V‐type ATPase complex assembly and metabolism‐related pathways. PCSK1, FBXO2, ACSL1, IRS2, and PTPRZ1 expression was markedly up‐regulated in type I g‐NENs. High IRS2 expression significantly correlated with a shorter time to recurrence. Conclusions: Our study provides a comprehensive proteomic signature based on DIA‐LC/MS/MS and highlights high IRS2 expression as a potential prognostic marker for type I gNENs. [ABSTRACT FROM AUTHOR]

Rationale: Cloxacillin and flucloxacillin are prone to degradation and polymerization in humid and hot environments, and their polymers have long been recognized to trigger allergic manifestations. A series of the degradation and polymerized impurities in cloxacillin and flucloxacillin were separated and characterized to ensure safe use of these drugs by the public. Methods: By studying the chromatographic behavior of the degradation impurities and polymerized impurities in reversed‐phase high‐performance liquid chromatography (RP‐HPLC) gradient elution, the impurities in cloxacillin and flucloxacillin were effectively separated and eluted. RP‐HPLC tandem ion trap/time‐of‐flight mass spectrometry (MS) was applied to characterize the structures of unknown impurities eluted from the RP‐HPLC methods for cloxacillin and flucloxacillin. The mechanisms of formation of the impurities in cloxacillin and flucloxacillin were also investigated. Results: The structures of 10 unknown impurities in cloxacillin and 8 unknown impurities in flucloxacillin were elucidated based on the high‐resolution MSn data at positive and negative modes, respectively. Six polymerized impurities were found and characterized, of which three were from the polymerization of cloxacillin and three were from the polymerization of flucloxacillin. Conclusions: The study on the impurity profiles of cloxacillin and flucloxacillin provided a scientific basis for improving their production processes and quality control. [ABSTRACT FROM AUTHOR]

This article presents a new method for detecting oxytocin (OT) in nonhuman primate plasma using liquid chromatography-tandem mass spectrometry (LC/MS/MS). OT is a neuropeptide that affects social behavior, and current methods for measuring OT levels have limitations. The researchers developed a protocol for sample preparation and analysis using LC/MS/MS, which allowed for accurate measurement of OT concentrations in plasma. The study found that the method was accurate and precise, with a lower limit of quantification of 0.41 pg/mL. This is the first reported method with sufficient sensitivity to measure OT in nonhuman primate plasma. [Extracted from the article]

BACKGROUND: Veterinary antibiotics are chemical compounds used to kill or inhibit the growth of pathogenic bacteria associated with animal diseases. These molecules can be defined by their retention times (tR) in liquid chromatography–mass spectrometry (LC–MS). One strategy to predict the tR of new veterinary antibiotics is the development of predictive quantitative structure–property relationships (QSPRs), which were used in this study. RESULTS: A database of 122 antibiotics was selected in which the tR was measured using a Hypersil GOLD column. An optimal three‐feature model was developed by integrating the unsupervised variable reduction, replacement method variable subset selection, and multiple linear regression. The negligible differences among the coefficient of determination and the root‐mean‐square error for the training set (R2 = 0.902 and RMSEC = 0.871) and test set (Q2 = 0.854 and RMSEP = 1.064) indicate a stable and predictive model. In a further step, a more in‐depth explanation of the mechanism of action of each descriptor in predicting the tR is provided, with the construction of the theoretical chemical space for accurate predictions of new antibiotics. CONCLUSION: The in silico model developed in this work identified three molecular descriptors associated with aqueous solubility, octanol–water partition coefficient, and the presence of negative and lipophilic atom pairs. The QSPR developed here could be implemented by agricultural and food chemists to identify and monitor existing and new antibiotics within the framework of LC–MS. The computational model was developed in accordance with five principles outlined by the Organization for Economic Co‐operation and Development. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

BACKGROUND: This study investigated per‐ and polyfluoroalkyl substances (PFASs) in 53 fruit and vegetable samples collected from a local wholesale and retail market in Sydney and a local supermarket in Newcastle. As there is limited information about PFAS levels in vegetables on the market, this study aimed to fill this gap and assess potential risks for humans through consumption of these vegetables. METHODS: QuEChERS extraction – a solid‐phase extraction method, a portmanteau word formed from 'quick, easy, cheap, effective, rugged and safe' – followed by enhanced matrix removal–lipid cleaning and liquid chromatography–tandem mass spectrometry analysis were used to detect 30 PFASs in vegetables. RESULTS: PFOA was detected in 7 out of the 53 samples, with concentrations of 0.038–1.996 ng g−1 fresh weight; PFOS was detected in 2 samples only, with concentrations ranging from 0.132 to 0.911 ng g−1 fresh weight. PFHxS was not detected in any sample in this study. PFOA and PFOS concentrations measured in vegetables in this study constituted daily intake of 2.03 ng kg−1 body weight (BW) and 1.98 ng kg−1 BW, respectively, according to recommended daily vegetable intake and BW data from the Australian Bureau of Statistics. The most sensitive population group is girls of 4–8 years of age. These estimated exposure levels represent up to 1.3% of the tolerable daily intake for PFOA (160 ng kg−1 BW) and 9.9% for PFOS (20 ng kg−1 BW) according to Food Standards Australia New Zealand. Consumption of the vegetables from the study locations poses a marginal risk to human health. © 2024 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Objective Methods Results Conclusion To develop a model based on maternal serum liquid chromatography tandem mass spectrometry (LC–MS/MS) proteins to predict spontaneous preterm birth (sPTB).This nested case–control study used the data from a cohort of 2053 women in China from July 1, 2018, to January 31, 2019. In total, 110 singleton pregnancies at 11–13+6 weeks of pregnancy were used for model development and internal validation. A total of 72 pregnancies at 20–32 weeks from an additional cohort of 2167 women were used to evaluate the scalability of the model. Maternal serum samples were analyzed by LC–MS/MS, and a predictive model was developed using machine learning algorithms.A novel predictive panel with four proteins, including soluble fms‐like tyrosine kinase‐1, matrix metalloproteinase 8, ceruloplasmin, and sex‐hormone‐binding globulin, was developed. The optimal model of logistic regression had an AUC of 0.934, with additional prediction of sPTB in second and third trimester (AUC = 0.868).First‐trimester modeling based on maternal serum LC–MS/MS identifies pregnant women at risk of sPTB, which may provide utility in identifying women at risk at an early stage of pregnancy before clinical presentation to allow for earlier intervention. [ABSTRACT FROM AUTHOR]

Background Objectives Animals Methods Results Conclusions and Clinical Importance Effects of the renin‐angiotensin‐aldosterone system (RAAS) inhibitors enalapril and telmisartan on circulating RAAS in dogs with proteinuric chronic kidney disease (pCKD) are undescribed.To characterize the RAAS in untreated dogs with pCKD compared to healthy, life‐stage‐ and sex‐matched controls, and in dogs with pCKD after 30 days of treatment with enalapril or telmisartan.Dogs with pCKD (n = 36) and healthy controls (n = 20).Retrospective study of banked samples and previously collected data. Day 0 serum equilibrium concentrations of angiotensin I, II, III, IV, 1‐5, and 1‐7, and aldosterone, and urinary aldosterone‐to‐creatinine ratio (UACR) from pCKD dogs were compared to values on day 30 of treatment with enalapril (0.5 mg/kg PO q12) or telmisartan (1 mg/kg PO q24h) and to those of healthy dogs. Data were analyzed using linear mixed models.Compared with healthy dogs, pCKD dogs had significantly higher Ang I, III, 1‐5, and 1‐7 concentrations, and UACR. Relative to pretreatment values, day 30 Ang II concentrations were significantly increased and decreased in telmisartan‐ and enalapril‐treated pCKD dogs, respectively (both P < .001). Mean (95% confidence interval) percentage change from pretreatment value in serum Ang 1‐7 concentration was significantly greater in telmisartan‐ (753% [489%‐1134%]) versus enalapril‐treated (149% [69%‐268%]) dogs (P < .001). Serum aldosterone decreased with treatment (P = .02 for enalapril, P < .001 for telmisartan), with no difference between groups at day 30.Circulating RAAS activity is higher in dogs with pCKD. Compared with enalapril, treatment with telmisartan caused significantly greater increases in the presumed beneficial peptide Ang 1‐7. [ABSTRACT FROM AUTHOR]

BACKGROUND RESULTS CONCLUSION The present study evaluated the effects of temperature, pH, light and chemical oxidation on fucoxanthin changes in terms of colour, antioxidant activity and metabolomic profile. Additionally, the correlation between antioxidant activity and identified metabolites was analysed.It was found that colour change was significantly reduced at elevated heat (100 °C, *∆E = 0.81 ± 0.05), reduced pH (pH 3, *∆E = 0.59 ± 0.04) and length of light exposure (*∆E = 3.16 ± 0.04). Antioxidant activity decreased under all treatments. Among the temperatures tested, fucoxanthin exhibited the highest activity at 60 °C, ranging from 0.92 to 3.04 mg Trolox equivalents (TE) g−1. Significant activity reductions (P < 0.05) were observed as a result of pH changes in the 2,2‐diphenyl‐1‐picrylhydrazyl and β‐carotene bleaching assays. Exposure to light 2: warm white lamp for 120 h significantly reduced antioxidant activity (0.01 to 1.70 mg TE g−1). Chemical oxidation also led to reduced activity, ranging from 0.18 to 0.29 mg TE g−1. Multivariate data analysis revealed distinct profiles for temperature, pH, light and chemical oxidation treatments. Liquid chromatography‐tandem mass spectrometry (LC‐MS/MS)‐based metabolomics analysis identified 10 metabolites, and significant correlations (P < 0.05) indicate that these metabolites contributed to the samples' antioxidant activities.In conclusion, fucoxanthin tolerates well at 60 °C, within pH range 3–9, and within 8 h of light exposure, as indicated by its consistent antioxidant activity and minimal colour change. Each treatment resulted in distinct metabolite concentrations, as shown by LC‐MS/MS‐based metabolomics analysis. Further research into these metabolites could advance the understanding of their roles and aid in optimising processing conditions to favour beneficial metabolites. © 2024 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Background Methods Results Conclusions 15‐oxo‐eicosatetraenoic acid (15‐oxo‐ETE), is a product of arachidonic acid (AA) metabolism in the 15‐lipoxygenase‐1 (15‐LOX‐1) pathway. 15‐oxo‐ETE was overproduced in the nasal polyps of patients with nonsteroidal anti‐inflammatory drug–exacerbated respiratory disease (N‐ERD). In this study we investigated the systemic biosynthesis of 15‐oxo‐ETE and leukotriene E4 (LTE4) and assessed their diagnostic value to identify patients with N‐ERD.The study included 64 patients with N‐ERD, 59 asthmatics who tolerated aspirin well (ATA), and 51 healthy controls. A thorough clinical characteristics of asthmatics included computed tomography of paranasal sinuses. Plasma and urinary 15‐oxo‐ETE levels, and urinary LTE4 excretion were measured using high‐performance liquid chromatography and tandem mass spectrometry. Repeatability and precision of the measurements were tested.Plasma 15‐oxo‐ETE levels were the highest in N‐ERD (p < .001). A receiver operator characteristic (ROC) revealed that 15‐oxo‐ETE had certain sensitivity (64.06% in plasma, or 88.24% in urine) for N‐ERD discrimination, while the specificity was rather limited. Modeling of variables allowed to construct the Aspirin Hypersensitivity Diagnostic Index (AHDI) based on urinary LTE4‐to‐15‐oxo‐ETE excretion corrected for sex and the Lund‐Mackay score of chronic rhinosinusitis. AHDI outperformed single measurements in discrimination of N‐ERD among asthmatics with an area under ROC curve of 0.889, sensitivity of 81.97%, specificity of 87.23%, and accuracy of 86.87%.We confirmed 15‐oxo‐ETE as a second to cysteinyl leukotrienes biomarker of N‐ERD. An index based on these eicosanoids corrected for sex and Lund‐Mackay score has a similar diagnostic value as gold standard oral aspirin challenge in the studied group of patients with asthma. [ABSTRACT FROM AUTHOR]

Summary Autophagy, involved in protein degradation and amino acid recycling, plays a key role in plant development and stress responses. However, the relationship between autophagy and phytohormones remains unclear. We used diverse methods, including CRISPR/Cas9, ultra‐performance liquid chromatography coupled with tandem mass spectrometry, chromatin immunoprecipitation, electrophoretic mobility shift assays, and dual‐luciferase assays to explore the molecular mechanism of strigolactones in regulating autophagy and the degradation of ubiquitinated proteins under cold stress in tomato (Solanum lycopersicum). We show that cold stress induced the accumulation of ubiquitinated proteins. Mutants deficient in strigolactone biosynthesis were more sensitive to cold stress with increased accumulation of ubiquitinated proteins. Conversely, treatment with the synthetic strigolactone analog GR245DS enhanced cold tolerance in tomato, with elevated levels of accumulation of autophagosomes and transcripts of autophagy‐related genes (ATGs), and reduced accumulation of ubiquitinated proteins. Meanwhile, cold stress induced the accumulation of ELONGATED HYPOCOTYL 5 (HY5), which was triggered by strigolactones. HY5 further trans‐activated ATG18a transcription, resulting in autophagy formation. Mutation of ATG18a compromised strigolactone‐induced cold tolerance, leading to decreased formation of autophagosomes and increased accumulation of ubiquitinated proteins. These findings reveal that strigolactones positively regulate autophagy in an HY5‐dependent manner and facilitate the degradation of ubiquitinated proteins under cold conditions in tomato. [ABSTRACT FROM AUTHOR]

Objectives Methods Results Conclusions To conduct a comprehensive proteomic analysis of normal salivary gland tissue, pleomorphic adenoma (PA), and carcinoma ex‐pleomorphic adenoma (CXPA), and validate the proteomic findings using immunohistochemistry.Six normal salivary gland tissues, seven PA and seven CXPA samples underwent laser microdissection followed by liquid chromatography coupled to mass spectrometry. Protein identification and quantification were performed using MaxQuant software. Statistical analysis and functional enrichment were conducted using the Perseus platform and STRING tool, respectively. Immunohistochemistry was used for validation.Comparative proteomic analysis revealed 2680 proteins across the three tissue types, with 799 significantly altered between groups. Translocation protein SEC63 homolog, Annexin A6 and Biglycan were up‐regulated in CXPA compared to PA. Decorin was markedly up‐regulated in both PA and CXPA compared to normal salivary gland (log2 fold changes of 7.58 and 7.38, respectively). Validation confirmed elevated levels of Biglycan and Decorin in the extracellular matrix of CXPA compared to PA.Proteomic analysis identified differential protein expression patterns associated with malignant transformation of PA into CXPA. Findings indicate a crucial role for extracellular matrix proteins, specifically Biglycan and Decorin, in the tumorigenic progression of PA and CXPA. [ABSTRACT FROM AUTHOR]

Protein glycosylation is the co‐ and/or post‐translational modification of proteins with oligosaccharides (glycans). This process is not template based and can introduce a heterogeneous set of glycan modifications onto substrate proteins. Glycan structures preserve biomolecular information from the cell, with glycoproteins from different cell types and tissues displaying distinct patterns of glycosylation. Several decades of research have revealed that glycan structures also differ between normal physiology and disease. This suggests that the information stored in glycoproteins and glycans can be utilized for disease diagnosis and monitoring. Methods that enable sensitive and site‐specific measurement of protein glycosylation in clinical settings, such as nano‐flow liquid chromatography tandem mass spectrometry, are therefore essential. The purpose of this perspective is to discuss recent advances in mass spectrometry and the potential of these advances to facilitate the detection and monitoring of disease‐specific glycoprotein glycoforms. Glycoproteomics, the system‐wide characterization of glycoprotein identity inclusive of site‐specific characterization of carbohydrate modifications on proteins, and glycomics, the characterization of glycan structures, will be discussed in this context. Quantitative measurement of glycopeptide markers via parallel reaction monitoring is highlighted. The development of promising glycopeptide markers for autoimmune disease, liver disease, and liver cancer is discussed. Synthetic glycopeptide standards, ambient ionization mass spectrometry, and consideration of glyco‐biomarkers in two‐ and three‐dimensional space within tissue will be critical to the advancement of this field. The authors envision a future in which glycoprotein mass spectrometry workflows will be integrated into clinical settings, to aid in the rapid diagnosis and monitoring of disease. [ABSTRACT FROM AUTHOR]

Apixaban, a direct oral anticoagulant drug (DOAC), typically does not require routine therapeutic drug monitoring (TDM), yet recent guidelines propose its use in specific clinical scenarios. While various antifactor Xa (anti‐FXa) chromogenic assays serve as useful proxies for measuring plasma exposure to apixaban in emergencies, they lack specificity compared with chromatographic methods. This research project is intended to the development and validation of a standardized protocol of liquid chromatography–tandem mass spectrometry (LC–MS/MS) in conformity with the ICH guidelines M10 for the measurement of apixaban in both plasma and dried plasma spots (DPSs). Samples preparation included protein precipitation after the addition of a deuterated internal standard (IS), and the chromatographic separation was carried out on a Thermo Scientific™ Accucore™ Polar Premium column (50 mm × 2.1 mm, i.d. 2.6 m). The newly developed LC–MS/MS method for apixaban mesurement from both plasma and DPS resulted linear over a wide concentration range (31.25–500 ng/mL), accurate, and reproducible without matrix effects, allowing for specific and rapid quantification. Stability was assessed on quality controls and a real sample, allowing the setting up of a robust TDM protocol that was applied to five anonymized plasma samples obtained from adult patients undergoing apixaban treatment at steady‐state. In conclusion our novel LC–MS/MS method is adequate for accurate apixaban quantitation from both plasma and DPS matrixes, and may thus facilitate the guidelines suggested implementation of apixaban TDM, even in peripheral hospitals through shipment of DPS at reference laboratories. [ABSTRACT FROM AUTHOR]

Rationale: Succinic acid and lactic acid have been associated with diarrhea in weaned piglets. The level of succinic acid and lactic acid in serum, meat, and intestinal contents is important to elucidate the mechanism of diarrhea in weaned piglets. Methods: A facile method was developed for the quantification of succinic acid and lactic acid in pigs' serum, intestinal contents, and meat using ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC/MS/MS). The serum samples underwent protein precipitation with methanol. The meat and intestinal contents were freeze-dried and homogenized using a tissue grinding apparatus. Methanol-water mixture (80:20, v/v) was used for homogenizing the meat, while water was used for homogenizing the intestinal contents. An additional step of protein precipitation with acetonitrile was required for the intestinal contents. The resulting solution was diluted with water before being analyzed by UHPLC/MS/MS. Separation of succinic acid and lactic acid could be achieved within 3 min using a Kinetic XB-C18 column. Results: The coefficients of variation for peak areas of succinic acid and lactic acid were less than 5.0%. The established method demonstrated good linearity as indicated by correlation coefficients exceeding 0.996. Additionally, satisfactory recoveries ranging from 88.58% to 108.8% were obtained. The detection limits (RS/N = 3) for succinic acid and lactic acid were determined to be 0.75 ng/mL and 0.02 µg/mL, respectively. Conclusion: This method exhibited high sensitivity, simplicity in operation, and small sample weight, making it suitable for quantitative determination of succinic acid and lactic acid in pigs' serum, intestinal contents, and meat. The method developed will provide valuable technical support in studying the metabolic mechanisms of succinic acid and lactic acid in pigs. [ABSTRACT FROM AUTHOR]

Rationale: Spironolactone is a steroidal drug prescribed for a variety of medical conditions and is extensively metabolized quickly after administration. Measurement of spironolactone and its metabolites remains challenging using mass spectrometry (MS) due to in-source fragmentation and relatively poor ionization using electrospray ionization. Therefore, improved methods of measurements are needed, particularly in the case of small sample volumes. Methods: Girard's reagent P (GP) derivatization of spironolactone was employed to improve response and provide an MS-based solution to the measurement of spironolactone and its metabolites. We performed ultra-high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UHPLC-ESIMS/MS) and ion mobility spectrometry (IMS)-high-resolution mass spectrometry (HRMS) to fully characterize the GP derivatization products. Analytes were studied in positive ionization mode, and MS/MS was performed using nonresonance and resonance excitation collision-induced dissociation. Results: We observed the successful GP derivatization of spironolactone and its metabolites using authentic chemical standards. A signal enhancement of 1-2 orders of magnitude was observed for GP-derivatized versions of spironolactone and its metabolites. Further, GP derivatization eliminated in-source fragmentation. Finally, we performed GP derivatization and ultra-high-performance liquid chromatography- high-resolution mass spectrometry (UHPLC-HRMS) in a small volume of murine serum (20 µL) from spironolactone-treated and control animals and observed multiple spironolactone metabolites only in the spironolactone-treated group. Conclusions: GP derivatization was proven to have advantageous mass spectral performance (e.g., limiting in-source fragmentation, enhancing signals, and eliminating isobaric analytes) for spironolactone and its metabolites. This work and the detailed characterization using ultra-high-performance liquid chromatography- high-resolution tandem mass spectrometry (UHPLC-HRMS/MS) and IMS serve as the foundation for future developments in reaction optimization and/or quantitative assay development. [ABSTRACT FROM AUTHOR]

Rationale: Alkylresorcinols (AR) are cereal-specific biomarkers and have recently been found in archaeological pots. However, their low concentrations and high susceptibility to degradation make them difficult to detect using conventional gas chromatography mass spectrometry (GC/MS). Here we describe the development of a more sensitive liquid chromatography mass spectrometry (LC/MS) method to detect these compounds. Method: A method based on the use of ultra-high-performance liquid chromatography (UHPLC) coupled to an Orbitrap mass analyser was established and validated for the detection of low-concentration ARs in pottery. During the preliminary experiments, UHPLC-Q/Orbitrap MS (ultra-high-performance liquid chromatography-quadrupole/Orbitrap mass spectrometry) was demonstrated to be more sensitive, and a wide range of AR homologues in cereal extracts were detected, unlike UHPLC-QTOFMS (ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry) and GC/MS. The developed method was utilised to profile AR homologue distribution in modern cereal samples and reanalyse AR-containing pots from the archaeological site of Must Farm. Results: A highly sensitive LC/MS method with a limit of detection (LOD) of 0.02 µg/g and a limit of quantification (LOQ) of 0.06 µg/g was used to profile ARs in five modern cereal grains. The obtained LOD is 250 times lower than that obtained using the conventional GC/MS approach. AR 21:0 was the most abundant homologue in all four Triticum spp.--einkorn, emmer, Khorasan wheat and common wheat. Meanwhile, AR 25:0 was the predominant homologue in barley, potentially enabling differentiation between wheat and barley. The developed LC/MS-based method was successfully used to analyse ARs extracted from Must Farm potsherds and identified the cereal species most likely processed in the pots--emmer wheat. Conclusion: The described method offers an alternative and more sensitive approach for detecting and identifying ARs in ancient pottery. It has been successfully utilised to detect AR homologues in archaeological samples and discriminate which cereal species--wheat and barley--were processed in the pots. [ABSTRACT FROM AUTHOR]

Rationale: Illegal addition of anti-infective drugs to cosmetics at low concentrations has been found. The illicit addition of anti-infective drugs encompasses a wide variety of medications. The current sample purification methods are inadequate to detect all these compounds. A sensitive, wide-coverage, and weak-matrix-effect measurement method needs to be established to address this issue. Methods: Samples were extracted using acetonitrile, diluted 25 times, and then analyzed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) to detect 111 anti-infective drugs. The method was validated and assessed for matrix effect before being applied to cosmetic products. Results: The calibration curves for the analytes exhibited a strong correlation coefficient (r > 0.995). The limit of detection ranged from 0.006 to 0.6 mg/kg. Matrix effects were significantly improved after a 25-fold dilution. The method was successfully applied to various cosmetics. Two of 82 samples tested contained lincomycin and miconazole, respectively. Conclusions: The developed method is quick and reliable to analyze anti-infective drugs in cosmetics, with potential for both qualitative and quantitative analyses. It is a valuable tool for cosmetic research and development, contributing to safer and more effective cosmetic products. [ABSTRACT FROM AUTHOR]

Rationale: Chlorothalonil (CHT), a broad-spectrum fungicide, has been employed widely to control foliar diseases, whereas with a major metabolite of polar 4-hydroxychlorothalonil (CHT-4-OH), only an acceptable nonpolar CHT residue is allowed by most countries. This study involves the method development for CHT residue in vegetables/fruits using liquid chromatography-tandem mass spectrometry (LC-MS/MS) with a novel modified discharge-adaptor (DA) interface. Methods: CHT residue was analyzed using LC-MS/MS with DA interface (LC-DAMS/MS), developed in our previous works. A DA was placed on the electrospray tip to switch the ionization modes. A modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) method was applied to extract CHT residue of vegetables/fruits efficiently with less sample preparation time and analysis cost. Results: CHT and CHT-4-OH spiked in four different vegetables/fruits were extracted using the modified QuEChERS method. After LC with isocratic elution, CHT and CHT-4-OH were separated within 3 min. Using LC-DA-MS/MS, the ion signals of CHT were improved two to three times, and the limit of quantification of 5 ng/g and linearity (r2 > 0.99) in the range of 5-200 ng/g were achieved using 10 g of vegetables/fruits. The precision and accuracy were within 15% each. The modified QuEChERS and LC-DA-MS/MS were applied to examine eight field-grown vegetables/fruits; 9.5 and 2588.9 ng/g of CHT were detected in two vegetables/fruits. Conclusion: LC-DA-MS/MS combined with modified QuEChERS was successfully applied to determine CHT residue <10 ng/g in vegetables/fruits and with satisfied validation results. The developed method could reduce both analysis cost and time, attributing to simplifications in modified QuEChERS, isocratic elution, and DA interface in LC-DA-MS/MS. [ABSTRACT FROM AUTHOR]

Octadecylamine (ODA) is the most widely used film‐forming amine in the nuclear industry. Its function is to minimize corrosion. In this work, we developed and validated a liquid chromatography‐mass spectrometry method that allows the quantification of ODA in the presence of other amines in the secondary system of nuclear power plants operating under all‐volatile treatment chemistry. Sample stabilities greater than 95% were achieved after 1 week of being taken in acetonitrile 1:1. The method showed a high selectivity allowing the measurement of ODA in the presence of other amines. The calibration curve was linear in the range of 0.0025–0.1025 mg/L. The limit of detection and limit of quantification (LOQ) were 1.8 and 2.2 µg/L, respectively for an injection volume of 3 µL. Lower LOQs can be achieved by increasing the injection volume, making the method applicable even in the first hours and days of treatment. The bias of the method was less than 10% and the relative standard deviation of reproducibility was less than 15%. The sample stabilization was robust and the uncertainty associated with the method was acceptable. The method was applied to a real sample taken after a few years of treatment and a concentration of 0.15 mg/L was measured. [ABSTRACT FROM AUTHOR]

The objective of the present research work was to demonstrate the application of liquid chromatography coupled with tandem mass spectrometry (LC‐MS/MS) for the separation, identification, and characterization of degradation products (DPs) of the drug lobeglitazone. The drug was subjected to various stress conditions such as oxidation, hydrolysis, thermal, and photolytic degradation as per the guidelines of the International Conference on Harmonization Q1A (R2). The drug was stable under thermal stress conditions, whereas it was susceptible to degradation in the other stress conditions forming four DPs. DPs were separated using a high‐performance LC system equipped with Zorbax SB C18 column (250 × 4.6 mm, 5 µm particles) using isocratic elution mode. The DPs were identified and characterized using MS and MS/MS. The chemical structure and fragmentation pattern were predicted for each degradant from the data obtained by mass studies. The drug and identified DPs were assessed by in‐silico approaches for predicting absorption, distribution, metabolism, and toxicity behavior. The in‐silico tools used for prediction were the pkCSM web server, ToxTree, and OSIRIS property explorer. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the bisphenol A (BPA) release from four CAD/CAM splint materials: three polycarbonate‐based (DD BioSplint C, Splint Plus Biostar, Temp Premium Flexible) and one polymethylmethacrylate‐based (Temp Basic) material. From each material, ten cylindrical samples (n = 40) were immersed in high‐performance liquid chromatography (HPLC) grade water following ISO 10993‐12 and incubated for 24 h in an incubation shaker at 37°C and 112 rpm. Following BPA derivatization, analysis was performed by high‐performance liquid chromatography–tandem mass spectrometry (HPLC‐MS/MS). After 24 h of incubation, all investigated materials released significant amounts of BPA compared to water blanks. The material‐dependent elution increased in the following order: DD BioSplint C < Splint Plus Biostar < Temp Basic < Temp Premium Flexible. Subtracting extraneous BPA, the concentrations ranged between 2.27 ng/mL and 12.65 ng/mL. After extrapolating the concentrations in relation to the average surface area of occlusal splints, the amount of BPA per mL exceeded the Tolerable Daily Intake (TDI) set by the European Union for a person weighing 70 kg by 1.32–6.16 times. Contrary to the release from previously investigated materials, BPA elution from CAD/CAM splint materials was highly elevated. Considering the increasing adaptation of CAD/CAM techniques, elution from them may represent a relevant BPA source in daily dental practice. [ABSTRACT FROM AUTHOR]

Skeletal muscle (SM) acts as a secretory organ, capable of releasing myokines and extracellular vesicles (SM‐EVs) that impact myogenesis and homeostasis. While age‐related changes have been previously reported in murine SM‐EVs, no study has comprehensively profiled SM‐EV in human models. To this end, we provide the first comprehensive comparison of SM‐EVs from young and old human primary skeletal muscle cells (HPMCs) to map changes associated with SM ageing. HPMCs, isolated from young (24 ± 1.7 years old) and older (69 ± 2.6 years old) participants, were immunomagnetically sorted based on the presence of the myogenic marker CD56 (N‐CAM) and cultured as pure (100% CD56+) or mixed populations (MP: 90% CD56+). SM‐EVs were isolated using an optimised protocol combining ultrafiltration and size exclusion chromatography (UF + SEC) and their biological content was extensively characterised using Raman spectroscopy (RS) and liquid chromatography mass spectrometry (LC‐MS). Minimal variations in basic EV parameters (particle number, size, protein markers) were observed between young and old populations. However, biochemical fingerprinting by RS highlighted increased protein (amide I), lipid (phospholipids and phosphatidylcholine) and hypoxanthine signatures for older SM‐EVs. Through LC‐MS, we identified 84 shared proteins with functions principally related to cell homeostasis, muscle maintenance and transcriptional regulation. Significantly, SM‐EVs from older participants were comparatively enriched in proteins involved in oxidative stress and DNA/RNA mutagenesis, such as E3 ubiquitin‐protein ligase TTC3 (TTC3), little elongation complex subunit 1 (ICE1) and Acetyl‐CoA carboxylase 1 (ACACA). These data suggest SM‐EVs could provide an alternative pathway for homeostasis and detoxification during SM ageing. [ABSTRACT FROM AUTHOR]

Summary: The plant hormone ethylene is of vital importance in the regulation of plant development and stress responses. Recent studies revealed that 1‐aminocyclopropane‐1‐carboxylic acid (ACC) plays a role beyond its function as an ethylene precursor. However, the absence of reliable methods to quantify ACC and its conjugates malonyl‐ACC (MACC), glutamyl‐ACC (GACC), and jasmonyl‐ACC (JA‐ACC) hinders related research.Combining synthetic and analytical chemistry, we present the first, validated methodology to rapidly extract and quantify ACC and its conjugates using ultra‐high‐performance liquid chromatography coupled to tandem mass spectrometry (UPLC‐MS/MS). Its relevance was confirmed by application to Arabidopsis mutants with altered ACC metabolism and wild‐type plants under stress.Pharmacological and genetic suppression of ACC synthesis resulted in decreased ACC and MACC content, whereas induction led to elevated levels. Salt, wounding, and submergence stress enhanced ACC and MACC production. GACC and JA‐ACC were undetectable in vivo; however, GACC was identified in vitro, underscoring the broad applicability of the method.This method provides an efficient tool to study individual functions of ACC and its conjugates, paving the road toward exploration of novel avenues in ACC and ethylene metabolism, and revisiting ethylene literature in view of the recent discovery of an ethylene‐independent role of ACC. [ABSTRACT FROM AUTHOR]

Aims: Therapeutic drug monitoring (TDM) has led to significant improvements in individualized medical care, although its implementation in oncology has been limited to date. Tyrosine kinase inhibitors (TKIs) are a group of therapies for which TDM has been suggested. Osimertinib is one such therapy used in the treatment of epidermal growth factor receptor (EGFR) mutation‐driven lung cancer. Herein, we describe a prospective pilot study involving 21 patients on osimertinib primarily as a preliminary evaluation of drug levels in a real‐world setting. Methods: Concentrations of the drug and its primary metabolites were measured with a validated liquid chromatography–mass spectrometry (LC–MS) assay across serial timepoints. As part of this study, inter‐individual variability by dose and ethnicity as well as intra‐individual variability across timepoints are explored. Furthermore, we attempted to validate dried blood spot (DBS)‐based quantitation as an accurate alternative to plasma quantitation. Results: Successful quantitation of osimertinib and primary metabolites was achieved for our subjects. Compound plasma levels were highly correlated to DBS levels. There was no significant difference in concentrations with ethnicity or dosing or intra‐individual variability across timepoints. Conclusions: As such, we demonstrate that TDM for osimertinib is practical for future trials. We also validated the use of DBS as an alternative to conventional quantitation for exploration of TDM for osimertinib in larger trials and for other targeted therapies. [ABSTRACT FROM AUTHOR]

Objective: Investigation of serum bile acid profiles in pregnancies complicated by gestational diabetes mellitus (GDM) in a multi‐ethnic cohort of women who are lean or obese. Design: Prospective cohort study. Setting: UK multicentre study. Population: Fasting serum from participants of European or South Asian self‐reported ethnicity from the PRiDE study, between 23 and 31 weeks of gestation. Methods: Bile acids were measured using ultra‐performance liquid chromatography‐tandem mass spectrometry. Log‐transformed data were analysed using linear regression in STATA/IC 15.0. Main outcome measures: Total bile acids (TBAs), C4, fasting glucose and insulin. Results: The TBAs were 1.327‐fold (1.105–1.594) increased with GDM in European women (P = 0.003). Women with GDM had 1.162‐fold (1.002–1.347) increased levels of the BA synthesis marker C4 (P = 0.047). In South Asian women, obesity (but not GDM) increased TBAs 1.522‐fold (1.193–1.942, P = 0.001). Obesity was associated with 1.420‐fold (1.185–1.702) increased primary/secondary BA ratio (P < 0.001) related to 1.355‐fold (1.140–1.611) increased primary BA concentrations (P = 0.001). TBAs were positively correlated with fasting glucose (P = 0.039) in all women, and with insulin (P = 0.001) and the Homeostatic Model Assessment for Insulin Resistance (HOMA‐IR) (P = 0.001) in women with GDM. Conclusions: Serum BA homeostasis in late gestation depends on body mass index and GDM in ethnicity‐specific ways. This suggests ethnicity‐specific aetiologies may contribute to metabolic risk in European and South Asian women, with the relationship between BAs and insulin resistance of greater importance in European women. Further studies into ethnicity‐specific precision medicine for GDM are required. [ABSTRACT FROM AUTHOR]

BACKGROUND: Dioscorea opposita Thunb. cv. Tiegun maturity (DM) is an important factor influencing its quality. However, there are few studies on the impact of harvest time on its maturation. In the present study, a NMR‐based metabolomics approach was applied to investigate the dynamic metabolic changes of D. opposita Thunb. cv. Tiegun at six different harvest stages: stage 1 (S1), stage 2 (S2), Stage 3 (S3), stage 4 (S4), stage 5 (S5) and stage 6 (S6). RESULTS: Principal component analysis showed distinct segregation of samples obtained from S1, S2 and S3 compared to those derived from S4, S5 and S6. Interestingly, these samples from the two periods were obtained before and after frost, indicating that frost descent might be important for DM. Eight differential metabolites responsible for good separation of different groups were identified by the principal component analysis loading plot and partial least squares‐discriminant analysis. In addition, quantitative analysis of these metabolites using liquid chromatography–tandem mass spectrometry determined the effects of harvest time on these metabolite contents, two of which, sucrose and allantoin, were considered as potential biomarkers to determine DM. CONCLUSION: The present study demonstrated that NMR‐based metabolomics approach could serve as a powerful tool to identify differential metabolites during harvesting processes, also offering a fresh insight into understanding the DM and the potential mechanism of quality formation. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Background: Citrus flower‐green tea (CT) is a scented tea processed from green tea (GT) and fresh citrus flower, which is favored by consumers due to its potential health benefits and unique citrus flavor. This study evaluated the quality of CT and revealed the mechanism of its quality formation. Results: The CT had a significant citrus flavor and a good antioxidant activity, and its sensory quality was superior to that of GT. Headspace solid‐phase microextraction‐gas chromatography–mass spectrometry (HS‐SPME‐GC–MS) analysis revealed that the scenting process resulted in a significant increase of alkenes such as β‐pinene, trans‐β‐ocimene, α‐farnesene, isoterpinolene, and γ‐terpinene, as well as a significant decrease of alcohols such as α‐terpineol, l‐menthol, and linalool in CT in comparison with GT. Liquid chromatography–tandem mass spectrometry (LC–MS/MS) analysis revealed that the levels of flavonoids (such as neohesperidin, hesperidin, tangeritin, hesperetin 5‐O‐glucoside, and nobiletin) and alkaloids (such as trigonelline and theobromine) in CT increased significantly after scenting process, while the levels of amino acids (such as valine and l‐phenylalanine) and organic acids (such as ascorbic acid) decreased significantly. Conclusion: These observations showed that the scenting process promoted the absorption of aroma from citrus flowers by GT and the changes in its non‐volatile metabolites, leading to the formation of citrus flavor quality in CT. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

In this study, plasma belimumab concentrations were measured over the course of treatment in systemic lupus erythematosus (SLE) patients on belimumab therapy, and intra‐ and interindividual variations in plasma belimumab concentration were evaluated. A single‐center prospective study was conducted at Oita University Hospital to evaluate trough plasma concentrations over the course of treatment in 13 SLE patients treated with intravenous belimumab. Plasma belimumab concentrations were measured by a validated ultra‐high performance liquid chromatography with tandem mass spectrometry method. The median age of the patients was 40 (interquartile range: 35–51) years and the median weight was 51.8 (47.0–58.1) kg. A mean of 9.4 (range: 1–13) blood samples was collected per patient at routine visits. The mean (± SD) plasma belimumab concentration was 33.4 ± 11.9 μg/mL in the patient with the lowest concentration and 170.0 ± 16.6 μg/mL in the patient with the highest concentration, indicating a 5‐fold difference between patients. On the other hand, the within‐patient coefficient of variation ranged from 7.1% to 35.7%, showing no large variations. No significant correlation was observed between plasma belimumab concentration and belimumab dose (mg/kg) (Spearman's rank correlation coefficient = 0.22, p =.54). Examinations of trough plasma belimumab concentrations over the course of treatment in patients with SLE showed small intraindividual variation but large interindividual variation. Plasma belimumab trough concentration varied widely among patients administered the approved dose. [ABSTRACT FROM AUTHOR]

A drug–drug interaction (DDI) trial of cytochrome P450 3A (CYP3A) is a necessary part of early‐phase trials of drugs mainly metabolized by this enzyme, but CYP3A DDI clinical trials do not have a standard design, especially for Chinese people. We aimed to offer specific recommendations for CYP3A DDI clinical trial design. This was an open, three‐cycle, self‐controlled study. Healthy subjects were given different administration strategies of CYP3A4 perpetrators. In each cycle, blood samples were collected before and within 24 h after the administration of midazolam, the CYP3A indicator substrate. The plasma concentrations of midazolam and 1‐hydroxymidazolam was obtained using liquid chromatography tandem mass spectrometry assay. For CYP3A inhibition, itraconazole exposure with a loading dose could increase the exposure of midazolam by 3.21‐fold based on maximum plasma concentration (Cmax), 8.37‐fold based on area under the curve Pharmacology Research & Perspectives for review only from zero to the time point (AUC0–t), and 11.22‐fold based on area under the curve from zero to infinity (AUC0–∞). The data were similar for itraconazole pretreatment without a loading dose. For CYP3A induction, the exposure of rifampin for 7 days decreased the plasma concentration of midazolam ~0.27‐fold based on Cmax, ~0.18‐fold based on AUC0–t, and ~0.18‐fold based on AUC0–∞. Midazolam exposure did not significantly change when the pretreatment of rifampin increased to 14 days. This study showed that itraconazole pretreatment for 3 days without a loading dose was enough for CYP3A inhibition, and pretreatment with rifampin for 7 days could induce near‐maximal CYP3A levels. [ABSTRACT FROM AUTHOR]

This bioequivalence research aims to evaluate the relative bioavailability and pharmacokinetic characteristics of ethinyl estradiol and drospirenone in the test preparation in comparison to the reference preparation during fasting conditions. A liquid chromatography method with tandem mass spectrometry was used to determine the concentrations of drospirenone and ethinyl estradiol in plasma. The pharmacokinetic parameters that were analyzed were the maximum plasma concentration (Cmax), time to achieve Cmax (tmax), elimination half life, and area under the concentration time curve of plasma (AUC0‐t, AUC0‐∞ for ethinyl estradiol, and AUC0‐72h for drospirenone). Both the AUC and Cmax parameters were determined to be between 80.00% and 125.00% (90% confidence intervals), which is the acceptable range. Based on the study findings, it was concluded that the test formulation, which includes 3 mg of drospirenone and 0.03 mg of ethinyl estradiol, demonstrated bioequivalence when compared to the reference formulation. [ABSTRACT FROM AUTHOR]

Lenvatinib (LEN), a multitarget tyrosine kinase inhibitor used in various cancer treatments, is mainly metabolized by cytochrome P450 3A (CYP3A) enzymes. The importance of therapeutic drug monitoring (TDM) in patients administered LEN has been proposed. Although some biomarkers of endogenous CYP3A activity have been reported, their utility in dosage adjustments has not been well evaluated. This study investigated the correlation between plasma LEN concentrations and endogenous urinary CYP3A biomarkers in clinical practice. Concentrations of plasma LEN (N = 225) and CYP3A biomarkers (cortisol, 6β‐hydroxycortisol, deoxycholic acid, and 1β‐hydroxydeoxycholic acid) in urine (N = 214) from 20 patients (hepatocellular carcinoma, N = 6; thyroid cancer, N = 3; endometrial cancer, N = 8; and renal cell carcinoma, N = 3) collected for consultation for up to 1 year were evaluated using liquid chromatography–tandem mass spectrometry. Moreover, plasma trough LEN concentrations were predicted using a three‐compartment model with linear elimination for outpatients administered LEN before sample collection. Moderate correlations were observed between the quantified actual concentrations and the predicted trough concentrations of LEN, whereas there was no correlation with endogenous urinary CYP3A biomarkers. The utility of endogenous urinary CYP3A biomarkers could not be determined. However, TDM for outpatients administered orally available medicines may be predicted using a nonlinear mixed effect model (NONMEM). This study investigated the utility of endogenous urinary CYP3A biomarkers for personalized medicine and NONMEM for predicting plasma trough drug concentrations. These findings will provide important information for further clinical investigation and detailed TDM. [ABSTRACT FROM AUTHOR]

Zotizalkib (ZTK, TPX‐0131) is a fourth‐generation highly effective inhibitor of wild‐type anaplastic lymphoma kinase (ALK) and ALK‐resistant mutations that can penetrate the central nervous system. It exhibited greater potency compared to all five officially approved ALK inhibitors. The aim of this study was to develop a rapid, accurate, eco‐friendly, and highly sensitive ultra‐high‐performance liquid chromatography‐tandem mass spectrometry (UHPLC‐MS/MS) method for measuring the concentration of ZTK in human liver microsomes (HLMs). The validation aspects of the current UHPLC‐MS/MS methodology in the HLMs were conducted in accordance with the bioanalytical method validation standards specified by the US Food and Drug Administration. ZTK and encorafenib were separated using an Agilent C8 column (Eclipse Plus) and an isocratic mobile phase. The calibration curve for the developed ZTK exhibited a linear relationship within the concentration range of 1–3000 ng/mL. The results from the Analytical Green‐ness Metric Approach program (0.76) suggested that the created method demonstrated a significant degree of environmental sustainability. The in vitro half‐life (t1/2) and intrinsic clearance (Clint) of ZTK were determined to be 15.79 min and 51.35 mL/min/kg, respectively that suggests the ZTK exhibits characteristics similar to those of a medication with a high extraction ratio. These approaches are crucial for the progress of novel pharmaceutical development, especially in improving metabolic stability. [ABSTRACT FROM AUTHOR]

Though bioaccumulation of pharmaceuticals by aquatic organisms continues to receive scientific attention, the internal disposition of these contaminants among different tissue compartments of fish species has been infrequently investigated, particularly among fish at different trophic positions. We tested a human to fish biological read‐across hypothesis for contaminant disposition by examining tissue‐specific accumulation in three understudied species, longnose gar (Lepisosteus osseus; piscivore), gizzard shad (Dorosoma cepedianum; planktivore/detritivore), and smallmouth buffalo (Ictiobus bubalus; benthivore), from a river influenced by municipal effluent discharge. In addition to surface water, fish plasma, and brain, gill, gonad, liver, and lateral muscle fillet tissues were analyzed via isotope dilution liquid chromatography tandem mass spectrometry. Caffeine and sucralose, two common effluent tracers, were quantitated at low micrograms per liter levels in surface water, while an anticonvulsant, carbamazepine, was observed at levels up to 37 ng/L. The selective serotonin reuptake inhibitors (SSRIs) fluoxetine and sertraline and primary metabolites were detected in at least one tissue of all three species at low micrograms per kilogram concentrations. Within each species, brain and liver of select fish contained the highest levels of SSRIs compared to plasma and other tissues, which is generally consistent with human tissue disposition patterns. However, we observed differential accumulation among specific tissue types and species. For example, mean levels of sertraline in brain and liver tissues were 13.4 µg/kg and 1.5 µg/kg in gizzard shad and 1.3 µg/kg and 7.3 µg/kg in longnose gar, respectively. In contrast, smallmouth buffalo did not consistently accumulate SSRIs to detectable levels. Tissue‐specific eco‐exposome efforts are necessary to understand mechanisms associated with such marked bioaccumulation and internal dispositional differences among freshwater fish species occupying different trophic positions. Environ Toxicol Chem 2024;43:1894–1902. © 2024 The Author(s). Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. [ABSTRACT FROM AUTHOR]

Background: Alcohol‐associated cardiomyopathy (ACM) is a cardiac muscle disease characterized by inflammation and oxidative stress. Thromboxane‐prostanoid receptor (TP‐R) plays an important role in the pathogenesis of cardiovascular disease. Herein, we hypothesize that TP‐R mediates alcohol‐induced early cardiac injury. Methods: Eight‐week‐old male C57BL/6 wild‐type mice were fed a chronic ethanol (ET) or control diet (CON) for 10 days followed by a single binge of ethanol or maltose‐dextrin through oral gavage. A cohort of ethanol‐fed mice received SQ 29,548 (SQ), a TP‐R antagonist. RNA sequencing, real‐time PCR, and western blot analysis were performed on left ventricle to investigate alterations in genes and/or proteins mediating oxidative stress, inflammation, and cardiac remodeling. Sirius Red staining was performed to measure myocardial fibrosis. Results: RNA‐sequencing analysis of myocardium from CON and ET groups identified 142 genes that were significantly altered between the two groups. In particular, the gene expression of thioredoxin‐interacting protein (TXNIP), a component of NLR family pyrin domain containing 3 (NLRP3) signaling, which mediates oxidative stress and inflammatory response, was upregulated in response to ethanol exposure. The myocardial protein levels of TP‐R and thromboxane A2 synthase were increased upon alcohol exposure. Ethanol increased the levels of 4‐hydroxynonenal, a marker of oxidative stress, with a concomitant increase in the protein levels of TXNIP and NLRP3, and administration of SQ attenuated these effects. Additionally, ethanol increased the protein levels of pro‐inflammatory mediators, including tumor necrosis factor alpha and the NLRP3 downstream product, secretory interleukin 1 beta, and SQ blunted these effects. Finally, the Sirius red staining of the myocardium revealed an increase in collagen deposition in ethanol‐fed mice which was attenuated by TP‐R antagonism. Conclusion: This study demonstrates that ethanol promotes the NLRP3 signaling pathway within the myocardium, leading to a pro‐inflammatory milieu that potentially initiates early myocardial remodeling, and TP‐R antagonism attenuates this effect. [ABSTRACT FROM AUTHOR]

Human milk oligosaccharides (HMOs) are an important class of biomolecules responsible for the healthy development of the brain‐gut axis of infants. Unfortunately, their accurate characterization is largely precluded due to a variety of reasons – there are over 200 possible HMO structures whereas only 10s of these are available as authentic analytical standards. Furthermore, their isomeric heterogeneity stemming from their many possible glycosidic linkage positions and corresponding α/β anomericities further complicates their analyses. While liquid chromatography coupled to tandem mass spectrometry remains the gold standard for HMO analyses, it often times cannot resolve all possible isomeric species and thus warrants the development of other orthogonal approaches. High‐resolution ion mobility spectrometry coupled to mass spectrometry has emerged as a rapid alternative to condensed‐phase separations but largely has remained limited to qualitative information related to the resolution of isomers. In this work, we have assessed the use of permethylation to improve both the resolution and sensitivity of HMO analyses with cyclic ion mobility separations coupled with mass spectrometry. In addition to this, we have developed the first‐ever high‐resolution collision cross‐section database for permethylated HMOs using our previously established calibration protocol. We envision that this internal reference database generated from high‐resolution cyclic ion mobility spectrometry‐mass spectrometry will greatly aid in the accurate characterization of HMOs and provide a valuable, orthogonal, approach to existing liquid chromatography–tandem mass spectrometry‐based methods. [ABSTRACT FROM AUTHOR]

ABSTRACT This work aims to characterize the serum profile of athletes after the administration of ecdysteroids, natural steroid hormones recently reported to enhance athletic performance. The combination of mass spectrometry and chemometric tools may allow to differentiate physiological effects from post‐training and intake‐driven effects. Serum samples were collected from 46 healthy male volunteers and divided into four groups: control (two capsules/day of Peak Ecdysone without training), placebo (two capsules without ecdysteroids with training), Ec1 (two capsules/day Peak Ecdysone with training), and Ec2 (eight capsules/day Peak Ecdysone with training). Metabolic profiling was measured using a SCIEX Triple Quadrupole LC‐MS/MS system coupled with the Biocrates AbsoluteIDQ p180 kit, which allows quantitation of a large panel of metabolites that were subjected to multivariate analysis. Unsupervised analysis of the data found no significant differences between the placebo and the ecdysteroid supplementation groups. By merging Ec1 and Ec2 into a single group, coded as treated, a clear discrimination between the control and placebo groups was observed. Phosphatidylcholines were among the most significant features of ecdysteroids administration, showing a dose‐dependent effect in Ec1 and Ec2 groups. As specific metabolic phenotypes can result from years of training, the discrimination of physiological effects from those caused by the administration of banned substances can be a valuable analytical strategy for the interpretation of adverse analytical findings in the anti‐doping field. [ABSTRACT FROM AUTHOR]

BACKGROUND: As a type of biological control agent (BCA), Bacillus velezensis possesses the efficacy of inhibiting pathogenic microorganisms, promoting plant growth, and overcoming continuous cropping obstacles (CCOs). However, there is limited reporting on the optimization of the cultivation conditions for such biocontrol agents and their role as double‐stranded RNA (dsRNA) delivery vectors. RESULTS: In this study, a Bacillus velezensis strain HS‐3 was isolated from the root zone of tomato plants with in vitro anti‐Botrytis cinerea activity. The investigation into active compounds revealed that HS‐3 predominantly employs proteins with molecular weights greater than 3 kDa for its antifungal activity. Liquid chromatography–tandem mass spectrometry (LC–MS/MS) analysis identified various proteases and chitosanase, further suggesting that HS‐3 most likely employs these enzymes to degrade fungal cell walls for its antifungal effect. To optimize the production of extracellular proteins, fermentation parameters for HS‐3 were systematically optimized, leading to an optimized medium (OP‐M). HS‐3 cultured in OP‐M demonstrated enhanced capacity to assist tomato plants in withstanding CCOs. However, the presence of excessive nematodes in diseased soil resulted in the disease severity index (DSI) remaining high. An RNA interference mechanism was further introduced to HS‐3, targeting the nematode tyrosine phosphatase (TP) gene. Ultimately, HS‐3 expressing dsRNA of TP in OP‐M effectively assisted tomatoes in mitigating CCOs, reducing DSI to 2.2% and 17.8% of the control after 45 and 90 days of growth, respectively. CONCLUSION: The advantages of Bacillus velezensis in crop disease management and the mitigation of CCOs become even more pronounced when utilizing both optimized levels of endogenous enzymes and introduced nematode‐targeting dsRNA. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]