High-performance Liquid Chromatography-tandem Mass Research Articles

A Support Vector Machine-Assisted Metabolomics Approach for Non-Targeted Screening of Multi-Class Pesticides and Veterinary Drugs in Maize

The contamination risks of plant-derived foods due to the co-existence of pesticides and veterinary drugs (P&VDs) have not been fully understood. With an increasing number of unexpected P&VDs illegally added to foods, it is essential to develop a non-targeted screening method for P&VDs for their comprehensive risk assessment. In this study, a modified support vector machine (SVM)-assisted metabolomics approach by screening eligible variables to represent marker compounds of 124 multi-class P&VDs in maize was developed based on the results of high-performance liquid chromatography–tandem mass spectrometry. Principal component analysis and orthogonal partial least squares discriminant analysis indicate the existence of variables with obvious inter-group differences, which were further investigated by S-plot plots, permutation tests, and variable importance in projection to obtain eligible variables. Meanwhile, SVM recursive feature elimination under the radial basis function was employed to obtain the weight-squared values of all the variables ranging from large to small for the screening of eligible variables as well. Pairwise t-tests and fold changes of concentration were further employed to confirm these eligible variables to represent marker compounds. The results indicate that 120 out of 124 P&VDs can be identified by the SVM-assisted metabolomics method, while only 109 P&VDs can be found by the metabolomics method alone, implying that SVM can promote the screening accuracy of the metabolomics method. In addition, the method’s practicability was validated by the real contaminated maize samples, which provide a bright application prospect in non-targeted screening of contaminants. The limits of detection for 120 P&VDs in maize samples were calculated to be 0.3~1.5 µg/kg.

Prediction of motor and non-motor Parkinson's disease symptoms using serum lipidomics and machine learning: a 2-year study.

Identifying biological factors which contribute to the clinical progression of heterogeneous motor and non-motor phenotypes in Parkinson's disease may help to better understand the disease process. Several lipid-related genetic risk factors for Parkinson's disease have been identified, and the serum lipid signature of Parkinson's disease patients is significantly distinguishable from controls. However, the extent to which lipid profiles are associated with clinical outcomes remains unclear. Untargeted high-performance liquid chromatography-tandem mass spectrometry identified >900 serum lipids in Parkinson's disease subjects at baseline (n = 122), and the potential for machine learning models using these lipids to predict motor and non-motor clinical scores after 2 years (n = 67) was assessed. Machine learning models performed best when baseline serum lipids were used to predict the 2-year future Unified Parkinson's disease rating scale part three (UPDRS III) and Geriatric Depression Scale scores (both normalised root mean square error = 0.7). Feature analysis of machine learning models indicated that species of lysophosphatidylethanolamine, phosphatidylcholine, platelet-activating factor, sphingomyelin, diacylglycerol and triacylglycerol were top predictors of both motor and non-motor scores. Serum lipids were overall more important predictors of clinical outcomes than subject sex, age and mutation status of the Parkinson's disease risk gene LRRK2. Furthermore, lipids were found to better predict clinical scales than a panel of 27 serum cytokines previously measured in this cohort (The Michael J. Fox Foundation LRRK2 Clinical Cohort Consortium). These results suggest that lipid changes may be associated with clinical phenotypes in Parkinson's disease.

Benzylic rearrangement for urinary analysis of guanidino and ureido compounds in cardiac surgery-associated acute kidney injury using high-performance liquid chromatography-tandem mass spectrometry.

RationaleBecause acute kidney injury (AKI) is closely related to poor prognosis in critically ill patients, developing biomarkers for its prediction and early diagnosis is particularly important. Endogenous guanidino compounds (GCs) and ureido compounds (UCs) can participate in various biochemical processes because of their important physiological activities. The aim of this study was to investigate the alteration profiles of urinary GCs/UCs as potential biomarkers in patients with cardiac surgery–associated acute kidney injury (CSA‐AKI) at different stages.MethodsGCs/UCs were reacted with benzil via benzylic rearrangement, and their derivatives were used to investigate fragmentation mechanisms using tandem mass spectrometry (MS/MS) in positive ion mode. Furthermore, a high‐performance liquid chromatography (HPLC)–MS/MS method was developed to measure the concentrations of GCs/UCs in urine samples taken from patients with CSA‐AKI at different time points.ResultsMS/MS analysis in positive ion mode showed that benzylic GCs/UCs exhibited similar fragmentation processes, which could produce the characteristic ion (C13H12N+) at m/z 182.0. Furthermore, an obviously different fragmentation pattern of benzylic UCs in the positive ion mode might be due to the neutral loss of the H2CO2 group under low collision energy. Of the eight selected GCs/UCs, methylguanidine exhibited significantly increased concentrations in urine when CSA‐AKI occurred, whereas guanidinoethyl sulfonate (GDS), homoarginine (HArg) and homocitrulline (HCit) exhibited decreased concentrations. After recovery from AKI, the urinary concentrations of the aforementioned GCs/UCs returned to normal. Some of the aforementioned metabolites with significant changes (GDS, HArg and HCit) had large areas under the curve in the receiver operating characteristic curve for distinguishing AKI stages on the third day after surgery.ConclusionsIn patients with CSA‐AKI, urinary GCs/UCs were significantly disrupted due to injured kidney, and some GC/UC metabolites exhibited a good ability to become potential biomarkers for AKI stages. The present study provides essential resources and new therapeutic targets for further research on CSA‐AKI.

Network analysis combined with experimental assessment to explore the therapeutic mechanisms of New Shenqi Pills formula targeting mitochondria on senile diabetes mellitus

BackgroundThe escalation of global population aging has accentuated the prominence of senile diabetes mellitus (SDM) as a consequential public health concern. Oxidative stress and chronic inflammatory cascades prevalent in individuals with senile diabetes significantly amplify disease progression and complication rates. Traditional Chinese Medicine (TCM) emerges as a pivotal player in enhancing blood sugar homeostasis and retarding complication onset in the clinical management of senile diabetes. Nonetheless, an evident research gap persists regarding the integration of TCM’s renal tonification pharmacological mechanisms with experimental validation within the realm of senile diabetes therapeutics.AimsThe objective of this study was to investigate the mechanisms of action of New Shenqi Pills (SQP) in the treatment of SDM and make an experimental assessment.MethodsNetwork analysis is used to evaluate target pathways related to SQP and SDM. Mitochondrial-related genes were obtained from the MitoCarta3.0 database and intersected with the common target genes of the disease and drugs, then constructing a protein-protein interaction (PPI) network making use of the GeneMANIA database. Representative compounds in the SQP were quantitatively measured using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) to ensure quality control and quantitative analysis of the compounds. A type 2 diabetes mice (C57BL/6) model was used to investigate the pharmacodynamics of SQP. The glucose lowering efficacy of SQP was assessed through various metrics including body weight and fasting blood glucose (FBG). To elucidate the modulatory effects of SQP on pancreatic beta cell function, we measured oral glucose tolerance test (OGTT), insulin histochemical staining and tunel apoptosis detection, then assessed the insulin-mediated phosphoinositide 3-kinase (PI3K)/protein kinase A (Akt)/glycogen synthase kinase-3β (GSK-3β) pathway in diabetic mice via Western blotting. Additionally, we observe the structural changes of the nucleus, cytoplasmic granules and mitochondria of pancreatic islet β cells.ResultsIn this investigation, we identified a total of 1876 genes associated with senile diabetes, 278 targets of SQP, and 166 overlapping target genes, primarily enriched in pathways pertinent to oxidative stress response, peptide response, and oxygen level modulation. Moreover, an intersection analysis involving 1,136 human mitochondrial genes and comorbidity targets yielded 15 mitochondria-related therapeutic targets. Quality control assessments and quantitative analyses of SQP revealed the predominant presence of five compounds with elevated concentrations: Catalpol, Cinnamon Aldehyde, Rehmanthin D, Trigonelline, and Paeonol Phenol. Vivo experiments demonstrated notable findings. Relative to the control group, mice in the model group exhibited significant increases in body weight and fasting blood glucose levels, alongside decreased insulin secretion and heightened islet cell apoptosis. Moreover, β-cells nuclear condensation and mitochondrial cristae disappearance were observed, accompanied by reduced expression levels of p-GSK-3β protein in islet cells (p < 0.05 or p < 0.01). Conversely, treatment groups administered SQP and Rg displayed augmented expressions of the aforementioned protein markers (p < 0.05 or p < 0.01), alongside preserved mitochondrial cristae structure in islet β cells.ConclusionOur findings suggest that SQP can ameliorate diabetes by reducing islet cell apoptosis and resist oxidative stress. These insulin-mediated PI3K/AKT/GSK-3β pathway plays an important regulatory role in this process.

A novel standard-free detection of adulteration method for sildenafil derivatives in dietary supplements.

The rapid and accurate detection of illegal adulteration of chemical drugs into dietary supplements is a big challenge in the food chemistry field. Detection of compounds without a standard reference is even more difficult; however, this is a common situation. Here in this study, a novel "standard-free detection of adulteration" (SFDA) method was proposed and phosphodiesterase-5 inhibitor derivatives were used as an example to figure out the possibility and reliability of this SFDA method. After analysis by quadrupole coupled time of flight-tandem mass spectrometry detection and multivariable statistics, six common fragment ions were chosen to indicate whether adulteration was present or not, while 20 characteristic fragment ions indicated whether adulteration was by nitrogen-containing heterocycles or by anilines. Furthermore, the quantitative methods were conducted by high-performance liquid chromatography-tandem mass spectrometry. In a word, this strategy allows for a quick determination of dietary supplement adulteration without any need for standard materials, improving the efficacy of food safety testing.

Research progress on the detection of water-soluble vitamins in food using liquid chromatography

Currently, liquid chromatography is widely used for the analysis and determination of water-soluble vitamins (WSVs) in functional foods. However, due to the diversity of sample characteristics and the requirement for purification accuracy, the chromatographic conditions and specific methods used vary. This paper reviews the chromatographic conditions of liquid chromatography techniques for detecting WSVs in food, as well as the selection of liquid chromatography methods in different application fields. The chromatographic conditions include chromatographic columns, column temperature, mobile phase, flow rate, and elution gradient, and the application scope of different chromatographic conditions is compared. Liquid chromatography methods include high-performance liquid chromatography and liquid chromatography-tandem mass spectrometry, and discussions are made on the applications and prospects of these two methods under different chromatographic conditions. Therefore, this review provides research insights into different chromatographic conditions and methods for food quality inspection and biochemical analysis research.

Association between serum vitamin D concentration and liver fibrosis in diabetes mellitus patients: a cross-sectional study from the NHANES database.

Liver fibrosis (LF) is a common complication of diabetes mellitus (DM). Studies have found that vitamin D (VD), as a modifiable factor has been reported to be associated with LF. The relationship between serum VD concentration and LF in DM patients has rarely been reported. The aim of this study was to assess the association between serum VD concentration and LF in DM patients. In this cross-sectional study, data of DM patients aged ≥ 45years were extracted from the National Health and Nutrition Examination Survey (NHANES 2017-2018). Serum VD concentration was measured by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Vibration controlled transient elastography (VCTE) was used to measure liver stiffness. Covariates included sociodemographic information, lifestyles, laboratory data, diseases history were extracted from the database. The weighted univariable and multivariable logistic regression models were utilized to explore the association between serum VD concentration and LF in DM patients, and were described as odds ratio (ORs) and 95% confidence intervals (CIs). Subgroup analyses based on BMI, liver steatosis, hypertension and dyslipidemia were further assessed the association. A total of 799 patients were included, of which 188 (23.53%) had LF. Higher serum VD concentration was associated with the lower odds of LF (OR = 0.33, 95% CI 0.19-0.59) and advanced LF (OR = 0.31, 95% CI 0.17-0.55) in DM patients after adjustment for race, liver steatosis, BMI, smoking, drinking, AST, ALT and physical activity, especially in patients with liver steatosis (OR = 0.28, 95% CI 0.13-0.59) and dyslipidemia (OR = 0.31, 95% CI 0.14-0.66), respectively. High serum VD concentration may have a potential benefit for maintain the liver health in DM patients.

Association of plasma kynurenine (KYN) with plasma osteopontin (OPN) in patients with locally invasive breast cancer.

e12551 Background: OPN is a matricellular protein implicated in several aggressive malignancies as both a prognostic marker and mechanistic driver of tumor development and metastasis, but little is known about what drives its increased expression in these settings. KYN, the biochemically active metabolite of tryptophan metabolism, is known to be involved in cancer immune evasion, cancer cell proliferation, chromosomal instability, angiogenesis, metastatic dissemination, and chemoresistance. In this study, we demonstrate that OPN levels are significantly elevated in plasma of patients requiring breast surgery for suspicious masses and is directly correlated with KYN plasma levels, which were also elevated in this population. Methods: We prospectively collected peripheral blood samples of 60 patients who required routine breast surgery for either benign or malignant masses. Plasma was obtained by centrifugation from the collected blood samples that were stored at -80℃. Samples were collected prior to any treatments or surgeries. This study is IRB approved, and participants provided written informed consent. High-performance liquid chromatography (HPLC) tandem mass spectrometry was carried out by the Dartmouth Clinical Pharmacology Shared Resource. Logistic regression was used to assess relationships among variables in the study population using the R language. Results: There is strong evidence to suggest that plasma KYN is directly related to OPN plasma levels in this group of 60 patients’ plasma samples with a correlation coefficient of 0.296 (p=0.024), 95% CI [0.0414-0.515]. Based on the p-value and confidence interval, there is statistical evidence to suggest a positive significant linear relationship between plasma KYN and OPN levels. Increased age and BMI, menopausal status, KYN’s substrate Tryptophan (TRP), and TNFα correlated neither with OPN levels nor event free survival (as defined by disease progression, complications including fractures, development of metabolic disease, or occurrence of secondary malignancy). Conclusions: Our data demonstrates a statistically significant linear relationship between KYN and OPN in plasma samples of patients undergoing breast surgery for suspicious lesions—offering new mechanistic insights into OPN—a biomarker implicated in cancer metastasis across several different cancer types. This data suggests that KYN, which is a known agonist of several harmful cancer-driving pathways, is directly related to OPN concentration in plasma of patients with early breast cancer. Further research investigating systemic concentrations of OPN in plasma is essential for gaining a comprehensive understanding of its mechanisms in tumor metastasis, as well as for exploring targeted therapeutic strategies to mitigate its detrimental effects.

Determination of cinnamaldehyde, thymol and eugenol in essential oils by LC–MS/MS and antibacterial activity of them against bacteria

Plant essential oils contain many secondary metabolites, some of which can effectively inhibit the growth of pathogenic microorganisms, so it is a very promising antibacterial agent. In this study, a qualitative and quantitative method based on high performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS) was developed for the simultaneous determination of three bioactive substances, cinnamaldehyde (CNM), thymol (THY), and eugenol (EUG), in the essential oils of plants. Necessary tests for linearity, limit of quantification, recovery, carryover contamination and precision of the method were carried out. Then, the antibacterial activity of 3 bioactive compounds against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) was evaluated by minimal inhibitory concentration and the synergistic antimicrobial effect. The results indicated that CNM, THY and EUG had good antibacterial activity. According to the results of fractional inhibitory concentration index (FICI), it is considered that CNM + THY and CNM + THY + EUG has obvious synergistic inhibitory effect on E. coli, and CNM + THY and CNM + EUG has obvious synergistic inhibitory effect on S. aureus. Finally, we analyzed the effect of the bioactive compounds on trace elements in bacteria and found significant changes in magnesium, calcium, copper and iron.

Pharmacokinetics and Bioequivalence of Two Formulations of Azithromycin Tablets: A Randomized, Single-Dose, Three-Period, Crossover Study in Healthy Chinese Volunteers Under Fasting and Fed Conditions.

Azithromycin is the first azalide antibiotic that is related to the macrolide family of antibiotics. Bioequivalence studies in China are initiated by the National Medical Products Administration (NMPA), which supports a generic consistency evaluation program for ensuring that generic products manufactured in China meet the required standards and provide equivalent therapeutic effects to their reference products. This study aimed to assess the bioequivalence of two azithromycin tablets under both fasting and fed conditions in healthy Chinese volunteers. This was a single-center, open-label, single-dose, randomized, three-way crossover trial with two independent groups (fasting group and fed group). A total of 72 healthy Chinese subjects (36 subjects in the fasting state and 36 subjects in the fed state) were enrolled and randomized to treatment. Blood samples were collected from 0 to 120 h after a single oral dose of a 250-mg generic azithromycin tablet (test, T) or branded azithromycin tablet (reference, R). The plasma concentrations of azithromycin were determined by high-performance liquid chromatography-tandem mass spectrometry (HPLC‒MS/MS). A non-compartmental analysis method was used to estimate the pharmacokinetic parameters. Adverse events were documented. In a fasting state, the bioequivalence of maximum plasma concentration (Cmax) was evaluated using the reference-scaled average bioequivalence (RSABE) approach (within-subject standard deviation, SWR >0.294), and the bioequivalence of area under the concentration-time curve from time 0 to the time of the last measurable plasma concentration (AUC0-t) and area under the concentration-time curve from time 0 extrapolated to infinity (AUC0-∞) were evaluated by the average bioequivalence (ABE) method (SWR < 0.294). The geometric mean ratio (GMR) of T/R for Cmax was 106.49%, while the 95% upper confidence bound was < 0. The GMRs of AUC0-t and AUC0-∞ were 103.34% and 101.28%, and the 90% confidence intervals (CIs) of the test/reference were 95.90-111.35%/94.85-108.15%, respectively. In the fed state, the RSABE approach was applied to estimate the bioequivalence of Cmax (SWR >0.294), and the ABE approach was applied to estimate the bioequivalence of AUC0-t and AUC0-∞ (SWR < 0.294). The GMR for Cmax was 99.80%, while the 95% upper confidence bound value was < 0. The GMRs of AUC0-t and AUC0-∞ were 97.07% and 98.15%, and the 90% CIs of the T/R were 90.02-104.68% and 90.66-106.25%, respectively. All adverse events were mild and transient. The trial indicated that the test and the reference azithromycin tablets were bioequivalent and well tolerated in healthy Chinese volunteers under both fasting and fed conditions. Clinicaltrials, ChiCTR2300071630 (retrospectively registered in 19/05/2023).

An LC-MS/MS method for the simultaneous determination of 6-cyanodopamine, 6-nitrodopamine, 6-nitrodopa, 6-nitroadrenaline and 6-bromodopamine in human plasma and its clinical application in patients with chronic kidney disease.

The aim of this study was to develop a high-performance liquid chromatography-tandem mass spectrometry method for the determination of 6-cyanodopamine, 6-nitrodopamine, 6-nitrodopa, 6-nitroadrenaline and 6-bromodopamine in human plasma samples. Strata-X 33 μm solid-phase extraction cartridges were used for the extraction of the catecholamines from human plasma samples. The catecholamines were separated in a 150 × 3 mm Shim-pack GIST C18-AQ column with 3μm particle size, placed in an oven at 40°C and perfused with 82% mobile phase A (acetonitrile-H2O; 90:10, v/v) + 0.4% acetic acid and 18% mobile phase B (deionized H2O) + 0.2% formic acid at a flow rate of 340 μl/min in isocratic mode. The injected volume was 4 μl and the run lasted 4 min. The method was linear from 0.1 to 20 ng/ml and the lower limit of quantification was 0.1 ng/ml for all analytes. The method was applied to evaluate the plasma levels of catecholamines in plasma of patients with chronic kidney disease and allowed the detection for the first time of circulating levels of the novel catecholamines 6-bromodopamine and 6-cyanodopamine.

Impact of homocysteine on acute ischemic stroke severity: possible role of aminothiols redox status

BackgroundAcute ischemic stroke (AIS) is one of the most common cerebrovascular diseases which accompanied by a disruption of aminothiols homeostasis. To explore the relationship of aminothiols with neurologic impairment severity, we investigated four aminothiols, homocysteine (Hcy), cysteine (Cys), cysteinylglycine (CG) and glutathione (GSH) in plasma and its influence on ischemic stroke severity in AIS patients.MethodsA total of 150 clinical samples from AIS patients were selected for our study. The concentrations of free reduced Hcy (Hcy), own oxidized Hcy (HHcy), free reduced Cys (Cys), own oxidized Cys (cysteine, Cyss), free reduced CG (CG) and free reduced GSH (GSH) were measured by our previously developed hollow fiber centrifugal ultrafiltration (HFCF-UF) method coupled with high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The concentration ratio of Hcy to HHcy (Hcy/HHcy), Cys to Cyss (Cys/Cyss) were also calculated. The neurologic impairment severity of AIS was evaluated using National Institutes of Health Stroke Scale (NIHSS). The Spearman correlation coefficient and logistic regression analysis was used to estimate and perform the correlation between Hcy, HHcy, Cys, Cyss, CG, GSH, Hcy/HHcy, Cys/Cyss and total Hcy with NIHSS score.ResultsThe reduced Hcy and Hcy/HHcy was both negatively correlated with NIHSS score in AIS patients with P = 0.008, r=-0.215 and P = 0.002, r=-0.249, respectively. There was no significant correlation of Cys, CG, GSH, HHcy, Cyss, Cys/Cyss and total Hcy with NIHSS score in AIS patients with P value > 0.05.ConclusionsThe reduced Hcy and Hcy/HHcy, not total Hcy concentration should be used to evaluate neurologic impairment severity of AIS patient.

#1777 Proteomic profiling of laser capture microdissection kidneys from diabetic nephropathy patients

Abstract Background and Aims Diabetes nephropathy (DN) remains the primary cause of end-stage renal disease (ESRD), warranting equal attention and separate analysis of glomerular, tubular, and interstitial lesions in its diagnosis and intervention. This study aims to identify the specific proteomics characteristics of DN, and assess changes in the biological processes associated with DN. Method 5 patients with DN and 5 healthy kidney transplant donor control individuals were selected for analysis. The proteomic characteristics of glomeruli, renal tubules, and renal interstitial tissue obtained through laser capture microscopy (LCM) were studied using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Results The expression of multiple heat shock proteins, tubulin, and heterogeneous ribonucleoprotein particle in glomeruli and tubules was significantly reduced. Differentially expressed proteins (DEPs) in the glomerulus showed significant enrichment in pathways related to cell junctions and cell movement, including the regulation of actin cytoskeleton and tight junction. DEPs in renal tubules were significantly enriched in glucose metabolism-related pathways, such as glucose metabolism, glycolysis/gluconeogenesis, and the citric acid cycle. Moreover, the glycolysis/gluconeogenesis pathway was a co-enrichment pathway in both DN glomeruli and tubules. Notably, ACTB emerged as the most crucial protein in the PPI analysis of DEPs in both glomeruli and renal tubules. Conclusion By using LCM and the proteomics analysis, we provide insights into the distinctive characteristics of each sub-region of renal tissue, shedding light on the impact of glycolysis metabolic disorder in DN and the potential role of the glomerular cytoskeleton and cell junction.

#2850 Elevation of serum indoxyl-sulfate in mice with normal kidney function triggers cardiac and vascular dysfunctions

Abstract Background and Aims Acute kidney disease (AKD) is associated with a long-term risk of cardiovascular mortality and major cardiovascular events, particularly heart failure and acute myocardial infarction. To date, the underlying mechanisms responsible for this elevated cardiovascular risk remain poorly understood. Patients with AKD show increased circulating levels of indoxyl-sulfate (IS), a uremic toxin known to promote oxidative stress, inflammation and apoptosis in cultured vascular and cardiac cells. In this context, we hypothesized that IS elevation during AKD might promote acute myocardial and vascular lesions, which over time favour the onset of cardiovascular events. In a first attempt to test this hypothesis, we aimed to verify whether IS elevation in mice with normal renal function induces myocardial and vascular dysfunctions similar to that observed in AKD. Method Thirty female C57BL6J mice were divided into three groups: control (CT, n = 10), IS (n = 10) and AKD (n = 10). AKD was induced by 5/6 nephrectomy. Blank surgeries were performed in the CT and IS groups. IS was administered continuously for 15 days via drinking water (2.5 g/L) to reach, in IS mice, the IS serum concentrations found in AKD mice, as monitored by a validated high-performance liquid chromatography-tandem mass spectrometry method. Cardiac and vascular functions were assessed by echocardiography at baseline and at D15. Expression of markers of contractility (SERCA-2a for myocardium, αSMA for aorta), inflammation (TNF-α, IL-1β), and endothelial dysfunction (VCAM-1, ICAM-1, iNOS) were assessed by qRT-PCR and western blot. The presence of cardiac lesions was assessed histologically. Results Elevation of serum IS concentrations was similar in IS and AKD mice (serum IS: 10.7 ± 3.4 µg/mL in IS-group and 10.9 ± 5.8 µg/mL in AKD-group vs. 4.0 ± 2.1 µg/mL in CT-group (p &amp;lt; 0.001 in CT vs IS and AKD group). Compared with CT mice, IS and AKD mice showed systolic and diastolic dysfunctions as evidenced by decreased ejection fraction (EF: 62.4% [58.0-72.3] in CT vs. 50.1% [45.0-57.0] in IS (p &amp;lt; 0.05 vs CT) and 51.3% [45.6-57.1] in AKD (p &amp;lt; 0.01 vs CT)), decreased fractional shortening (FS: 33.6% [30.1-40.4] in CT vs. 24.8% [21.9-29.7] in IS (p &amp;lt; 0.05 vs CT) and 25.8% [22.4-29.6] in AKD (p &amp;lt; 0.01 vs CT)) and increased isovolumic relaxation time (IVRT: 17.2 ± 1.6 ms in CT vs. 20.7 ± 1.3 ms in IS (p &amp;lt; 0.001 vs CT) and 19.0 ± 1.7 ms in AKD (p &amp;lt; 0.05 vs CT)), respectively. For all echocardiographic parameters assessed, there were no significant differences observed between IS and AKD mice. Myocardium from IS and AKD mice showed decreased expression of SERCA-2a and elevated expression of both IL-1β and TNF-α at the mRNA and protein levels compared to CT mice. Aortas from IS and AKD mice also showed decreased mRNA expression of α-SMA and increased mRNA expression of IL-1β, VCAM-1, and iNOS compared to aortas from CT mice. The mRNA and protein expression of these inflammatory and contractile markers were not statistically different in the hearts and aortas from IS compared to AKD mice. No signs of vascular dysfunction were observed in either of the groups on ultrasound. Conclusion Systemic exposure to IS in mice without renal failure leads to significant cardiac and vascular dysfunctions that were similar to those observed in mice with AKD. Additional studies are needed to confirm the causal role of IS in the cardiovascular impact of AKD, and to determine whether IS could represent a valuable prognostic tool and therapeutic target for preventing AKD-associated cardiovascular complications.

Rapid determination of 111 anti-infective drugs possibly added in cosmetics using high-performance liquid chromatography-tandem mass spectrometry with scheduled multiple reaction monitoring.

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. 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. The calibration curves for the analytes exhibited a strong correlation coefficient (r > 0.995). The limit of detection ranged from 0.006 to 0.6mg/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. 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.

Bisphenol A release from CAD/CAM splint materials.

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 24h in an incubation shaker at 37°C and 112rpm. Following BPA derivatization, analysis was performed by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). After 24h 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 2.27ng/mL and 12.65ng/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 70kg 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.

Determination of Sedative and Anesthetic Drug Residues in Aquatic Food Products Using Solid Phase Extraction (SPE) and Liquid Chromatography–Tandem Mass Spectrometry (LC–MS/MS)

The residues of sedative and anesthetic drugs in aquatic products are an important factor affecting food safety. In order to screen the residues of sedative and anesthesia drugs in aquatic products, a rapid and sensitive method was established using solid phase extraction (SPE) and high-performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS). The samples were extracted by 80% aqueous acetonitrile by an alumina column and separated by a C18 column. The mass spectra were determined in positive ion mode. The standard curves were matrix matched and quantified by the external standard method. The results showed that the linear ranges of the drugs in aquatic products were from 0.5 to 100 μg kg−1. The correlation coefficient (R 2) was greater than 0.990 and the detection limits were between 0.001 and 0.322 μg kg−1. The average recovery rate and relative standard deviation were between 78.64% and 112.15% and from 0.41%-8.26%. Overall, the developed method showed promising results for the simultaneous qualitative and quantitative determination of the drug residues in aquatic products.

Enhancing the efficiency of polypyrrole-dodecylbenzene sulfonic acid in-tube solid-phase microextraction coating for analysis of nitrogen-containing pesticides in water environments

Background: With the growing use of nitrogen-containing pesticides in agriculture, their residues in the environment have raised significant public health concerns.Objective: This study aimed to develop a novel PPy-DBSA/IT-SPME coating to enhance the detection efficiency of polar nitrogen-containing pesticides in water matrices.Methods: The preparation conditions were optimized, including pyrrole concentration at 7.0 mol/L, DBSA concentration at 0.014 mol/L, oxidant concentration at 0.35 mol/L, and a coating cycle repeated 10 times. High-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was employed for detection.Results: The novel coating effectively adsorbed 19 different categories of polar nitrogen-containing pesticides, including sulfonylureas, triazolopyrimidines, diphenyl ether herbicides, benzoylurea insecticides, and phenylurea herbicides, with unadsorbed rates below 10%. The analytical method achieved an average recovery rate of 61.92% to 115.21%, with an RSD below 5.0%. Detection and quantification limits ranged from 0.012 to 0.524 μg/L and 0.127 to 5.243 μg/L, respectively.Conclusion: The developed method is green, efficient, simple, and cost-effective. It offers an environmentally friendly and user-friendly approach for the detection of polar nitrogen-containing pesticide residues, demonstrating good recovery and precision. This method holds potential for wide application in environmental monitoring and food safety.

Determination of 13 potential anti-obesity agents in hair by dispersive liquid-liquid microextraction-assisted UHPLC-MS/MS

As the adulteration of dietary supplements with synthetic drugs remains a prevalent issue, the inclusion of anti-obesity agents may pose health risks, potentially leading to central nervous system or cardiovascular diseases. However, surveillance studies on the use of anti-obesity agents by the Chinese population are limited. This study aims to establish an efficient and rapid hair pretreatment method using dispersive liquid-liquid microextraction (DLLME) combined with high-speed grinding and develop a sensitive and accurate analytical method employing ultra high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) for detecting 13 potential anti-obesity agents in hair samples. Herein, hair samples were washed sequentially with 0.1% sodium dodecyl sulfate (SDS), water and acetone, and then ground at high speed using 1 mL of an extraction solution (internal standard solution-n-butanol-1.2 mol/L Na2HPO4, pH10.0, 100:400:500, v/v/v for procaterol; internal standard solution-ethyl acetate-1.2 mol/L Na2HPO4, pH8.0, 100:300:600, v/v/v for other 12 anti-obesity agents) while simultaneously performing DLLME. The developed method successfully detected 13 anti-obesity agents within 11 min, including bambuterol, clenbuterol, ractopamine, clorprenaline, formoterol, salbutamol, terbutaline, procaterol, phentermine, bupropion, sibutramine, desmethyl sibutramine, and N,N-didesmethyl sibutramine, which improved the screening efficiency. The calibration curves exhibited good linearity of 0.025–5 ng/mg, achieving correlation coefficients of r ≥ 0.99. The lower limits of quantification (LLOQs) for the analytes were 0.025 ng/mg, demonstrating acceptable levels of accuracy and precision. Recovery rates ranged between 73.30% and 107.47% across the three concentrations of 0.075, 0.375, and 3.75 ng/mg. The validated method was successfully applied to 369 real cases and detected six analytes, including bambuterol, salbutamol, terbutaline, sibutramine, desmethyl sibutramine, and N,N-didesmethyl sibutramine. This method offers several advantages, including simple pretreatment, high extraction efficiency, rapid extraction, solvent economy, and pollution mitigation, making it highly suitable for large-scale surveillance of usage of added anti-obesity agents.

Evaluation of spatial and temporal changes in illicit drug use in the Taipei metropolitan area via wastewater-based epidemiology

Taiwan, identified as pivotal in the Asian drug trafficking chain, has been experiencing a surge in illicit drug-related issues. Wastewater-based epidemiology (WBE) has emerged as a promising approach for comprehensive evaluation of actual illicit drug usage. This study presents the first WBE investigation of illicit drug consumption in Taiwan based on the analysis of wastewater from four wastewater treatment plants (WWTPs) in the Taipei metropolitan area. Additionally, it demonstrates a high correlation between the amounts of illicit drugs seized and influent concentrations over an extended period of time. The reliability of solid-phase extraction and analysis via high-performance liquid chromatography-tandem mass spectrometry (HPLC–MS/MS) was validated for 16 illicit drugs (methamphetamine, ketamine, cocaine, codeine, methadone, morphine, meperidine, fentanyl, sufentanil, para-methoxyamphetamine (PMA), para-methoxymethamphetamine (PMMA), 3,4-methylenedioxymethamphetamine (MDMA), cathinone, methcathinone, mephedrone (MEPH), and 4-methylethcathinone (4-MEC)). Methamphetamine, ketamine, and 4-MEC were consistently detected in all wastewater samples, underscoring their prevalence in the Taipei metropolitan area. Biochemical oxygen demand (BOD) and ammonia nitrogen (ammonia N) were employed to reduce uncertainty in estimations of population size during back-calculation of illicit drug consumption. The results indicate that methamphetamine was the most consumed drug (175–740 mg day−1 1000 people−1), followed by ketamine (22-280 mg day−1 1000 people−1). In addition, urban-related WWTPs exhibited higher consumption of methamphetamine and ketamine than did the suburban-related WWTP, indicating distinct illicit drug usage patterns between suburban and urban regions. Moreover, an examination of temporal trends in wastewater from the Dihua WWTP revealed a persistent predominance of ketamine and methamphetamine, consistent with statistical data pertaining to seizure quantities and urine test results. The study provides encouraging insight into spatial and temporal variations in illicit drug usage in the Taipei metropolitan area, emphasizing the complementary role of WBE in understanding trends in illicit drug abuse.