Proteomic insights into the pathophysiology of hypertension-associated albuminuria: Pilot study in a South African cohort.

BACKGROUND: Hypertension is an important public health priority with a high prevalence in Africa. It is also an independent risk factor for kidney outcomes. We aimed to identify potential proteins and pathways involved in hypertension-associated albuminuria by assessing urinary proteomic profiles in black South African participants with combined hypertension and albuminuria compared to those who have neither condition. METHODS: The study included 24 South African cases with both hypertension and albuminuria and 49 control participants who had neither condition. Protein was extracted from urine samples and analysed using ultra-high-performance liquid chromatography coupled with mass spectrometry. Data were generated using data-independent acquisition (DIA) and processed using Spectronaut™ 15. Statistical and functional data annotation were performed on Perseus and Cytoscape to identify and annotate differentially abundant proteins. Machine learning was applied to the dataset using the OmicLearn platform. RESULTS: Overall, a mean of 1,225 and 915 proteins were quantified in the control and case groups, respectively. Three hundred and thirty-two differentially abundant proteins were constructed into a network. Pathways associated with these differentially abundant proteins included the immune system (q-value [false discovery rate] = 1.4 × 10- 45), innate immune system (q = 1.1 × 10- 32), extracellular matrix (ECM) organisation (q = 0.03) and activation of matrix metalloproteinases (q = 0.04). Proteins with high disease scores (76-100% confidence) for both hypertension and chronic kidney disease included angiotensinogen (AGT), albumin (ALB), apolipoprotein L1 (APOL1), and uromodulin (UMOD). A machine learning approach was able to identify a set of 20 proteins, differentiating between cases and controls. CONCLUSIONS: The urinary proteomic data combined with the machine learning approach was able to classify disease status and identify proteins and pathways associated with hypertension-associated albuminuria.

Measurement uncertainty estimation of free drug concentrations in clinical laboratories using equilibrium dialysis.

OBJECTIVES: Developing procedures based on equilibrium dialysis (ED) that allow measuring the free drug concentration in plasma improves therapeutic drug monitoring (TDM) in those cases where its measurement is justified. However, this procedure requires specific sample preparation and presents different pitfalls, which are not error-free. As with any result provided by a clinical laboratory, this one should be as accurate as possible to allow a correct clinical interpretation. The measurement uncertainty (MU) is a parameter that enables the accuracy of results to be known, and that is mandated by ISO 15189. Herein, this study suggests how the MU for the results of the free drug concentrations in serum could be estimated when an ED is used. METHODS: A combination of the top-down and bottom-up approaches was used to estimate the MU based on the ISO/TS 20914:2019 and JCGM 100:2008 guidelines, including the concentration of free phenytoin in serum, as an example. Different scenarios were incorporated considering or not a significant bias related to the primary drawbacks of ED: the non-specific binding, the volume shift effect and the Gibbs-Donnan effect. RESULTS: The expanded uncertainties estimated ranged between 13.0 and 30.9 %. The highest MU corresponded to the free drug concentrations in serum results when significant biases related to the volume shift and Gibbs-Donnan effects exist. CONCLUSIONS: A detailed estimation of MU for free drug concentrations is presented using ED, considering different scenarios. This study could stimulate clinical laboratories to perform MU studies and its application in TDM.

Biomonitoring urinary organophosphorus flame retardant metabolites by liquid-liquid extraction and ultra-high performance liquid chromatography-tandem mass spectrometry and their association with oxidative stress.

Organophosphate flame retardants (OPFRs) are widely used as substitutes for traditional brominated flame retardants, necessitating a reliable and sensitive method for biomonitoring their urinary metabolites to assess human exposure. This study conducted biomonitoring of 10 metabolites of OPFRs in 152 adults and assessed their association with oxidative stress biomarkers 8-hydroxydeoxyguanosine and 8-hydroxyguanosine. Urinary metabolites of OPFRs were released via enzymatic deconjugation. The addition of sodium chloride to the urine samples increases the ionic strength, inducing a salting-out effect that reduces the solubility of these compounds, thereby facilitating their extraction with a mixture of ethyl acetate and acetonitrile. Then, the metabolites of OPFRs were quantified by ultra-high performance liquid chromatography-tandem mass spectrometry, and we validated the method for linear range, precision, matrix effect, and method detection limit. The detection limit of the metabolites of OPFRs ranged from 0.01 to 0.2 µg/L, and these metabolites were detected with high frequencies ranging from 25.0 to 98.68% in the urine samples. The concentration of bis (2-chloroethyl) phosphate was significantly higher in males than in females, with the geometric mean concentration of 0.88 µg/L for males and 0.53 µg/L for females, respectively. Spearman correlation analysis revealed weak but statistically significant positive correlations among the urinary metabolites. Bayesian kernel machine regression analysis showed a significant positive association between elevated urinary concentrations of metabolites of OPFRs and increased oxidative stress levels. Di-n-butyl phosphate was identified as the metabolite that significantly contributed to the elevated level of 8-hydroxyguanosine.

A robust method for simultaneous determination of eight B vitamins in human serum by liquid chromatography tandem mass spectrometry.

The level of vitamin B group in human serum is an important index of human health. Among B vitamins, cyanocobalamin in serum is unstable and its content is extremely low. Rapid and simultaneous detection of multiple B vitamins including cyanocobalamin is a challenge. Herein, we have developed a rapid and stable method that can realize the determination of thiamine, riboflavin, nicotinamide, pantothenic acid, pyridoxic acid, biotin, 5-methyltetrahydrofolate, and cyanocobalamin simultaneously in 6 min. The method was established based on protein precipitation with methanol and then chromatographic separation was achieved using Waters acquity ultra-high-performance liquid chromatography high strength silica T3 column, which was stable and sensitive especially for cyanocobalamin. Limit of quantification, precision, trueness, and matrix effect were validated according to the European Medicines Agency and United States Food and Drug guidelines and Clinical and Laboratory Standards Institute guidelines on bioanalytical method. The limit of quantification for thiamine, riboflavin, nicotinamide, pantothenic acid, pyridoxic acid, biotin, 5-methyltetrahydrofolate, and cyanocobalamin was 0.4, 0.4, 0.8, 2.0, 0.4, 0.1, 0.4, and 0.04 ng/mL separately, respectively. Intra- and interday precisions were 1.1%-12.4% and 2.0%-13.5%, respectively. The relative errors were between 0.3% and 13.3%, and the matrix effects were between 2.6% and 10.4%.

Ultra-high-performance liquid chromatography with tandem mass spectrometry method for cellular toxicity and pharmacokinetic study of PEG1K polymers.

Polyethylene glycol (PEG) is one of the most commonly used polymers in drug delivery systems. The investigation of the pharmacokinetic behavior of PEG is important for revealing the toxicity and efficiency of PEG-related Nano-drug delivery systems. A high through-put and selective ultra-high-performance liquid chromatography with tandem mass spectrometry (UHPLC-MS/MS) method coupled with collision-induced dissociation (CID) in source technique was developed and validated to determine PEG1K polymers in cellular samples in this study. The countless precursor ions of PEG1K are dissociated in the source to generate numerous product ions which have different numbers of subunits. The transition of [M+H]+ precursor ions → product ions at m/z 177.1 (four subunits)→89.1 (two subunits) was selected to determine PEG1K due to its high sensitivity. The UHPLC-MS/MS method coupled with CID in the source showed good linearity over the range of 0.1-10 µg/mL. Intra-day and inter-day accuracies and precisions of the assay were all within ± 12.39%. The assay was successfully applied to a cellular pharmacokinetic study of PEG1K in human breast cancer cells. The cytotoxicity of PEG1K polymers was also studied and the results indicated that the cytotoxicity of PEG1K was not significant in the range of 5-1200 µg/mL.

Analysis of 14 ß-agonists in pork using an automated wooden tip-based solid-phase microextraction device and ultra-high-performance liquid chromatography-tandem mass spectrometry.

This study introduces a cost-effective, automated ultra-high-performance liquid chromatography-tandem mass spectrometry method for the detection of 14 ß-agonists in pork using a novel solid-phase microextraction probe composed of polyacrylonitrile and molecularly imprinted polymer. Integrated into an automated extraction device, the probe optimizes extraction prior to analysis while reducing expenses and time compared to traditional solid-phase extraction procedures. The method validation followed the Chinese National Standard (GB/T 27404-2008) and examined limits of detection, limits of quantification, matrix effects, linearity, intraday, and interday precision. Average recovery rates ranged from 71.6% to 82.2%, with relative standard deviations less than 15%. Limits of detection and limits of quantification ranged from 0.09 to 0.39 and 0.27 to 0.99 µg/kg, respectively. The new method identified positive samples more accurately than the current National Standard GB/T 31658.22-2022 and demonstrated its potential for routine assessment and regulatory compliance in the detection of ß-agonists in pork.

Comparative pharmacokinetics of 11 major bioactive components between two dosage forms of Qixue Shuangbu Prescription in rats by ultra-high-performance liquid chromatography-tandem mass spectrometry.

Although Qixue Shuangbu Prescription (QSP) is a classic Chinese medicine prescription for treating chronic heart failure. Low bioavailability due to the insolubility and poor biofilm permeability of the main bioactive ingredients of QSP is still a key factor limiting its efficacy. In this study, a novel self-microemulsifying drug delivery system was proposed to effectively improve the bioavailability of QSP. The qualified ultra-high-performance liquid chromatography-tandem mass spectrometry methodology was established to investigate the pharmacokinetics characteristics of the QSP self-microemulsifying drug delivery system. Our results showed that 11 components in the self-microemulsifying drug delivery system group had prolonged T1/2 and MRT0-t values compared with QSP extract. The Cmax of calycosin-7-glucoside (CG), vanillic acid and paeoniflorin increased 2.5 times, 2.4 times and 2.3 times, respectively. The relative bioavailability values of CG, paeoniflorin and ononin were most significantly affected, increasing by 383.2%, 336.5% and 307.1%, respectively. This study promoted the development of new dosage forms of QSP and provided a useful reference for improving dosage forms to solve the problem of low bioavailability of traditional Chinese medicine.

Metabolomics captures the differential metabolites in the replication pathway of snakehead vesiculovirus regulated by glutamine.

Snakehead vesiculovirus (SHVV) is a negative-sense single-stranded RNA virus that infects snakehead fish. This virus leads to illness and mortality, causing significant economic losses in the snakehead aquaculture industry. The replication and spread of SHVV in cells, which requires glutamine as a nitrogen source, is accompanied by alterations in intracellular metabolites. However, the metabolic mechanisms underlying the inhibition of viral replication by glutamine deficiency are poorly understood. This study utilized liquid chromatography-mass spectrometry to measure the differential metabolites between the channel catfish Parasilurus asotus ovary cell line infected with SHVV under glutamine-containing and glutamine-deprived conditions. Results showed that the absence of glutamine regulated 4 distinct metabolic pathways and influenced 9 differential metabolites. The differential metabolites PS(16:0/16:0), 5,10-methylene-THF, and PS(18:0/18:1(9Z)) were involved in amino acid metabolism. In the nuclear metabolism functional pathway, differential metabolites of guanosine were observed. In the carbohydrate metabolism pathway, differential metabolites of UDP-d-galacturonate were detected. In the signal transduction pathway, differential metabolites of SM(d18:1/20:0), SM(d18:1/22:1(13Z)), SM(d18:1/24:1(15 Z)), and sphinganine were found. Among them, PS(18:0/18:1(9Z)), PS(16:0/16:0), and UDP-d-galacturonate were involved in the synthesis of phosphatidylserine and glycoprotein. The compound 5,10-methylene-THF provided raw materials for virus replication, and guanosine and sphingosine are related to virus virulence. The differential metabolites may collectively participate in the replication, packaging, and proliferation of SHVV under glutamine deficiency. This study provides new insights and potential metabolic targets for combating SHVV infection in aquaculture through metabolomics approaches.

Functionalized graphene oxide as a nanocarrier for delivering oridonin to improve anti-breast cancer cell activity.

In this study, a targeted nanocarrier was developed by functionalizing graphene oxide with polyethyleneimine and folic acid, intended for loading oridonin. The nanocarrier was successfully synthesized and characterized using an ultraviolet spectrum, Fourier transform infrared spectroscopy and scanning electron microscopy. The nanocarrier demonstrated a remarkable oridonin loading capacity, reaching 424.8 µg/mg, as determined by ultra-high performance liquid chromatography. In vitro drug release experiments exhibited a pH-dependent release profile, with a higher cumulative release in an acidic environment. The release mechanism followed the Ritger-Peppas equation model. Cytotoxicity assays indicated minimal toxicity of the nanocarrier. Enhanced cellular uptake by MCF7 cells was observed for carriers functionalized with folate and polyethyleneimine. These findings highlight the potential of functionalized graphene oxide as a promising carrier for oridonin delivery in biomedical applications.

Analysis of Antioxidant Properties and Compounds in Different Rosa Taxa Fruits Using UV-Vis and UPLC-TQ-MS Techniques.

This comprehensive analysis of the fruits of Rosa spp. (FR) evaluates their chemical components and antioxidant activity. The study quantified total flavonoids and polyphenols using aluminum trichloride colorimetric assay and Folin-Ciocalteu methods, with the fruit of Rosa. laxa Rtez. var. mollis Yü et Ku. sample exhibiting the highest concentrations of 59.21 mg/g and 81.13 mg/g, respectively. Ultra-High-Performance Liquid Chromatography-Triple Quadrupole Mass Spectrometry (UPLC-TQ-MS) assessed seven primary components, with notable levels of euscaphic acid, ursolic acid, and gallic acid. Antioxidant activities were tested using DPPH and ABTS methods, showing strong activities in samples the fruits of Rosa. persica Mickx ex Juss. and Rosa. laxa Rtez. var. kaschgarica (Rupr.) Y. L. Han. Chemometric analyses, including similarity, cluster, principal component, and grey relational analyses, were used to explore relationships between FR varieties and their antioxidant properties. The study provides a vital basis for future FR quality assessments.

Optimization and Spectrum-Effect Analysis of Ultrasonically Extracted Antioxidant Flavonoids from Persicae Ramulus.

The objectives of this study were to optimize the ultrasonic-assisted flavonoid extraction process from PR and to establish fingerprints in order to analyze the spectrum-effect relationship of antioxidant activity. The ultrasonic-assisted flavonoid extraction process from PR was optimized using RSM, and the fingerprints of twenty-eight batches of flavonoids from PR were established using UHPLC. Meanwhile, the in vitro antioxidant activity of PR was evaluated in DPPH and ABTS free radical-scavenging experiments. Then, the peaks of the effective antioxidant components were screened using the spectrum-effect relationships. The results show that the optimal extraction yield of flavonoids from PR was 3.24 ± 0.01 mg/g when using 53% ethanol, a 1:26 (g/mL) solid-liquid ratio, and 60 min of ultrasonic extraction. Additionally, the clearance of two antioxidant indices by the flavonoids extracted from PR had different degrees of correlation and showed concentration dependence. Simultaneously, the similarity of the UHPLC fingerprints of twenty-eight batches of PR samples ranged from 0.801 to 0.949, and four characteristic peaks, namely peaks 4, 12, 21, and 24, were screened as the peaks of the components responsible for the antioxidant effect of PR using a GRA, a Pearson correlation analysis, and a PLS-DA. In this study, characteristic peaks of the antioxidant effects of PR were screened in an investigation of the spectrum-effect relationship to provide a scientific basis for the study of pharmacodynamic substances and the elucidation of the mechanism of action of the antioxidant effect of PR.

Spectroscopic Relationship between XOD and TAOZHI Total Polyphenols Based on Chemometrics and Molecular Docking Techniques.

Xanthine oxidase (XOD) is a key enzyme that promotes the oxidation of xanthine/hypoxanthine to form uric acid, and the accumulation of uric acid leads to hyperuricaemia. The prevalence of gout caused by hyperuricaemia is increasing year by year. TAOZHI (TZ) can be used for the treatment of rheumatic arthralgia due to qi stagnation and blood stasis and contains a large number of polyphenolic components. The aim of this study was to investigate the relationship between chromatograms and XOD inhibition of 21 batches of TZ total polyphenol extract samples. Chemometric methods such as grey correlation analysis, bivariate correlation analysis, and partial least squares regression were used to identify the active ingredient groups in the total polyphenol extracts of TZ, which were validated using molecular docking techniques. The total polyphenol content contained in the 21 batches did not differ significantly, and all batches showed inhibitory effects on XOD. Spectroeffect correlation analysis showed that the inhibitory effect of TZ on XOD activity was the result of the synergistic effect of multiple components, and the active component groups screened to inhibit XOD were F2 (4-O-Caffeoylquinic acid), F4, and F10 (naringenin). The molecular docking results showed that the binding energies of all nine dockings were lower than -7.5 kcal/mol, and the binding modes included hydrogen bonding, hydrophobic forces, salt bridges, and π-staking, and the small molecules might exert their pharmacological effects by binding to XOD through the residue sites of the amino acids, such as threonine, arginine, and leucine. This study provides some theoretical basis for the development and utilisation of TZ total polyphenols.

Follicular fluid lipidomics analysis reveals altered lipid signatures in patients with polycystic ovary syndrome.

BACKGROUND: This research investigates the metabolic profiles of follicular fluid (FF) samples from patients with polycystic ovary syndrome (PCOS) undergoing in vitro fertilisation and aims to identify diagnostic and therapeutic biomarkers for PCOS through lipidomic analysis. METHODS: We performed non-targeted lipid analysis of FF samples from women with PCOS (n = 6) and normal controls (n = 6) using ultra-high-performance liquid chromatography-tandem mass spectrometry. Differential lipids between the two groups were screened using multidimensional statistical analysis, followed by fold change analysis and t-tests to identify potential PCOS biomarkers. RESULTS: Multivariate statistical analysis revealed significant differences in FF lipid levels between the PCOS and control groups. Five different lipids were selected as standards, with p < .05. Phosphatidylcholine (PC), the main differentially expressed lipid, was significantly increased in the FF of the POCS group and was closely related to other lipids. CONCLUSIONS: Using ultra-high-performance liquid chromatography-tandem mass spectrometry, we investigated lipid biomarkers based on FF lipidomics to provide useful information for the discovery of diagnostic markers for PCOS. Our study identified five distinct lipids as potential markers of PCOS, with PC being the primary aberrant lipid found in the FF of patients with PCOS.

Follicular fluid (FF) is a complex microenvironment involved in oocyte growth, follicular maturation and germ cell­somatic cell communication. All metabolites during oocyte growth are collected from the FF. This study used lipidomic analysis to identify differences in FF lipids between normal women and those diagnosed with polycystic ovary syndrome (PCOS). The pathogenesis of PCOS is associated with abnormal metabolism of glyceroglycolipids and sphingomyelin. Here, we found that phosphatidylcholine is the main abnormal lipid in FF in patients with PCOS. Our study informs the future research into the development of diagnostic markers for PCOS to be used in clinical practice.

[Determination of six bisphenols in human urine by ultra-high performance liquid chromatography-tandem mass spectrometry].

OBJECTIVE: To develop and validate a solid phase extraction-ultra-high performance liquid chromatography-tandem mass spectrometry method for the determination of six bisphenols(bisphenol S, bisphenol F, bisphenol A, 2, 2'-methylenediphenol, bisphenol AF, bisphenol AP) in urine. METHODS: After enzymolysis of urine sample, the target substances were quickly purified and extracted by WAX solid phase extraction column. On ACQUITY BEH C_(18) column(2.1 mm×100 mm, 1.7 µm), the mobile phase of water and methanol was used to separate. Finally, multi-reaction detection was carried out under electrospray negative ion scanning, and quantification was carried out by internal standard method. RESULTS: The correlation coefficients(r) of the target compounds were all more than 0.998 in the range of 0.1-50.0 ng/mL, the linearity was good, and the detection limits were all lower than 0.1 ng/mL. The recoveries of the three standard concentrations(0.5, 5.0 and 50.0 ng/mL) were all between 80% and 120%, and the relative standard deviation was less than 20%(n=5). The standard reference material was detected and the concentration was within the reference range. CONCLUSION: This method can be used to detect six bisphenols in urine quickly and accurately, is suitable for the trace analysis of bisphenol compounds in human urine.

[Application of chromatographic retention time correction in untargeted screening].

OBJECTIVE: Chromatographic retention time correction is one of the important steps to effectively improve the accuracy of identification. This article proposed a strategy for untargeted screening of biological samples based on retention time correction. METHODS: A pre-treatment method for biological samples was established. The conditions of liquid chromatography and mass spectrometry were optimized. Fourteen compounds were selected as calibration agents. The retention time correction of different samples, different injection time, different brands of instruments, changing chromatographic column and changing mobile phase were investigated. RESULTS: Calibration agents had a wide coverage, good stability and no interference with sample determination. They could be uniformly distributed in the chromatogram in both positive and negative ion modes. The chromatogram was divided into several time intervals. Calibration agents in each time period were used for retention time linear correction, and the correction effects were good. CONCLUSION: The retention time correction method could eliminate the retention time drift caused by experimental conditions, improve the accuracy of qualitative analysis, and help to solve the problem of high false positive result based on mass spectrum information.

[Action mechanisms of Qianlie Jindan Tablets on chronic nonbcterial prostatitis in rats: An exploration based on non-targeted urine metabolomics].

OBJECTIVE: To explore the mechanisms of Qianlie Jindan Tablets (QLJD) acting on chronic nonbacterial prostatitis (CNP) in rats based on non-targeted urine metabolomics. METHODS: According to the body mass index, we equally randomized 30 eight-week-old male SD rats into a blank control, a CNP model control and a QLJD medication group. We established the CNP model in the latter groups and, from the 4th day of modeling, treated the rats in the blank and model control groups intragastrically with normal saline and those in the QLJD medication group with QLJD suspension, qd, for 30 successive days. Then we detected the changes in the metabolites of the rats by ultra-high-performance liquid chromatography-tandem mass spectrometry, and identified the differential metabolites in different groups by multivariate statistical analysis, followed by functional annotation of the differential metabolites. RESULTS: Eight common metabolites were identified by metabolomics analysis, of which 5 were decreased in the CNP model controls and increased in the QLJD medication group, while the other 3 increased in the former and decreased in the latter group. Creatinine and genistein were important differential metabolites, and the arginine and proline metabolic pathways and isoflavone biosynthesis pathways were the main ones for QLJD acting on CNP. Compared with the blank controls, the model controls showed up-regulated arginine and proline metabolic pathways, increased production of creatinine, down-regulated isoflavone biosynthetic pathway and decreased production of genistein. The above changes in the model controls were all reversed in the QLJD medication group. CONCLUSION: QLJD acts effectively on CNP in male rats by regulating L-arginine and proline metabolic pathways, as well as the isoflavone biosynthesis pathway and naringenin metabolism.

[Identification of chemical components in Qinggu San reference sample of classial prescription based on UHPLC-Q/Orbitrap HRMS combined with molecular network technology].

The method of ultra-high performance liquid chromatography-quadrupole-electrostatic field orbitrap high-resolution mass spectrometry(UHPLC-Q/Orbitrap HRMS)combined with molecular network was developed in this study for rapidly analyzing the chemical components of the Qinggu San reference sample of classical prescription. Firstly, an ACQUITY UPLC BEH Shield RP_(18) column(2.1 mm×100 mm, 1.7 µm)was used, and acetonitrile and 0.1% formic acid were taken as the mobile phases for gradient elution. The flow rate was 0.4 mL·min~(-1), and the column temperature was 30 ℃. Under these conditions, the mass spectrum data were collected in both positive and negative ion modes of the heated electrospray ionization source. Subsequently, the mass spectrum data of the Qinggu San reference sample were uploaded to the Global Natural Products Social Molecular Network(GNPS)platform for calculation and analysis, and a visual molecular network was built with Cytoscape 3.8.2 software. On this basis, the chemical components of the Qinggu San reference sample were identified by fragmentation regularity of standard compounds, retention time, accurate relative molecular weight of HR-MS, characteristic fragment ions information, literature, and databases. Finally, a total of 105 chemical components were identified and speculated in the Qinggu San reference sample, including 19 iridoid glycosides, 23 flavonoids, 15 phenylpropanoids, 11 triterpene saponins, and 37 other components. Meanwhile, two of these components are potential new compounds. The method used in this study not only achieved rapid and accurate identification of chemical components in the Qinggu San reference sample and provided a scie-ntific basis for the study of pharmacological substances and quality control of Qinggu San compound preparations but also provided a refe-rence for the rapid identification of chemical components in traditional Chinese medicine compound preparations.

[Metabolite identification and metabolic pathway analysis of Platycodonis Radix extracts from Tongcheng city in rats].

In this study, we delved into the prototypical components and metabolites of Platycodonis Radix extracts(PRE) from Tongcheng city in plasma, urine and feces of rats, and revealed its metabolic pathways and metabolic rules in vivo. The prototypical components and metabolites of PRE in rats were characterized and identified by ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry(UPLC-Q-TOF-MS) and mass defect filter(MDF). The biological samples were analyzed by ACQUITY UPLC BEH C_(18)(2.1 mm×100 mm, 1.7 µm), with 0.1% formic acid water(A)-0.1% formic acid acetonitrile(B) as mobile phase, and the biological samples were analyzed in negative ion mode by electrospray ionization mass spectrometry(ESI-MS). Twelve prototypical saponins and twenty-seven metabolites were detected in plasma, urine and feces of rats treated with PRE by oral administration. Eleven prototypical components and nine metabolites were detected in plasma, eleven prototypical components and eight metabo-lites were detected in urine, and ten prototypical components and twenty metabolites were detected in feces. Further studies showed that the metabolic pathways of PRE in rats mainly include oxidation, reduction, acetylation, stepwise hydrolytic deglycosylation, glucuronidation and so on. This study provides a scientific basis for clarifying the pharmacological basis and mechanism of PRE from Tongcheng city.

Urine Metabolites Changes in Acute Myocardial Infarction Rats via Metabolomic Analysis.

OBJECTIVES: To screen biomarkers for forensic identification of acute myocardial infarction (AMI) by non-targeted metabolomic studies on changes of urine metabolites in rats with AMI. METHODS: The rat models of the sham surgery group, AMI group and hyperlipidemia + acute myocardial infarction (HAMI) group were established. Ultra-high performance liquid chromatography-mass spectrometry (UPLC-MS) was used to analyze the changes of urine metabolic spectrometry in AMI rats. Principal component analysis, partial least squares-discriminant analysis, and orthogonal partial least squares-discriminant analysis were used to screen differential metabolites. The MetaboAnalyst database was used to analyze the metabolic pathway enrichment and access the predictive ability of differential metabolites. RESULTS: A total of 40 and 61 differential metabolites associated with AMI and HAMI were screened, respectively. Among them, 22 metabolites were common in both rat models. These small metabolites were mainly concentrated in the niacin and nicotinamide metabolic pathways. Within the 95% confidence interval, the area under the curve (AUC) values of receiver operator characteristic curve for N8-acetylspermidine, 3-methylhistamine, and thymine were greater than 0.95. CONCLUSIONS: N8-acetylspermidine, 3-methylhistamine, and thymine can be used as potential biomarkers for AMI diagnosis, and abnormal metabolism in niacin and nicotinamide may be the main causes of AMI. This study can provide reference for the mechanism and causes of AMI identification.

Rapid Screening of 34 Emerging Contaminants in Surface Water by UHPLC-Q-TOF-MS.

OBJECTIVES: To establish a rapid screening method for 34 emerging contaminants in surface water by ultra-high performance liquid chromatography-quadrupole-time of flight mass spectrometry (UHPLC-Q-TOF-MS). METHODS: The pretreatment conditions of solid phase extraction (SPE) were optimized by orthogonal experimental design and the surface water samples were concentrated and extracted by Oasis® HLB and Oasis® MCX SPE columns in series. The extracts were separated by Kinetex® EVO C18 column, with gradient elution of 0.1% formic acid aqueous solution and 0.1% formic acid methanol solution. Q-TOF-MS 'fullscan' and 'targeted MS/MS' modes were used to detect 34 emerging contaminants and to establish a database with 34 emerging contaminants precursor ion, product ion and retention times. RESULTS: The 34 emerging contaminants exhibited good linearity in the concentration range respectively and the correlation coefficients (r) were higher than 0.97. The limit of detection was 0.2-10 ng/L and the recoveries were 81.2%-119.2%. The intra-day precision was 0.78%-18.70%. The method was applied to analyze multiple surface water samples and 6 emerging contaminants were detected, with a concentration range of 1.93-157.71 ng/L. CONCLUSIONS: The method is simple and rapid for screening various emerging contaminants at the trace level in surface water.