[Determination of two perfluorinated compounds in urine by liquid chromatography-tandem mass spectrometry].

Objective: To establish a method for the determination of two perfluorinated compounds in urine by liquid chromatography-tandem mass spectrometry. Methods: In November 2022, urine samples were extracted by acidic methanol, purified by WAX solid phase extraction column, and eluted with methanol water, then Waters ACQUITY UPLC BEH C18 column (100 mm×2.1 mm, 1.7 µm) was used with 1.0 mmol/L ammonium acetate solution and methanol as mobile phase. The gradient elution was carried out, the detection was carried out by electrospray negative ion multiple response monitoring (MRM) mode, and the quantitative method was internal standard method. Results: Perfluorooctanoic acid and perfluorooctane sulfonic acid had a good linear relationship in the concentration range of 0.5-50.0 µg/L, and the correlation coefficient was >0.999. The limit of detection was 0.017 µg/L, and the limit of quantitation was 0.005 µg/L. The average recoveries were 96.3% and 101.8%, respectively. Days of precision were 3.5%-6.2% and 3.1%-7.4%, respectively, daytime precision were 4.3%-6.8% and 4.7%-8.1%, respectively. Conclusion: The established method of liquid chromatography-tandem mass spectrometry is high sensitivity and accuracy, and is suitable for the determination of perfluorooctanoic acid and perfluorooctane sulfonic acid in human urine.

Validación de la metodología para cuantificar el fluconazol y sus impurezas orgánicas en materia prima por cromatografía líquida de alta resolución

Introducción. La eficiencia de una metodología para analizar una sustancia farmacológica puede verse afectada por las condiciones reales del laboratorio de cada país, incluyendo el clima. Por esta razón, se requiere validar el método con las pautas recomendadas para ello y optimizar el proceso, para asegurar el éxito y la confianza en los resultados. Objetivo. Validar una metodología para la cuantificación simultánea del fluconazol (materia prima) y sus impurezas orgánicas mediante cromatografía líquida de alta resolución con detector de arreglo de diodos en condiciones de clima tropical y con todos los requisitos normativos. Materiales y métodos. Se hicieron pruebas previas a la validación del método: idoneidad del sistema, estudio de filtros, límite de cuantificación, ausencia del error sistemático, estudios de degradación forzada y estabilidad de las soluciones. Además, se validaron: la especificidad, la linealidad, la exactitud, la precisión y la robustez. Resultados. La pureza espectral del método se logró al obtener la separación de los productos de degradación de los picos de los analitos. La estabilidad de las soluciones no se vio afectada, en la frecuencia evaluada de 24 horas, a temperatura ambiente y de refrigeración. Se obtuvo una linealidad con coeficientes de correlación mayores o iguales a 0,999 para la valoración y mayores o iguales a 0,997 para las impurezas. La recuperación estuvo en el rango de 98 a 102,0 % de fluconazol, con una exactitud entre el 80 y el 120 % para las impurezas. El factor de repetibilidad y reproducibilidad no superó la desviación estándar relativa del 2,0 % para la valoración y, la del 5,0 %, para las impurezas, lo cual mostró una solidez adecuada del método. Además, se obtuvo un tiempo corto de ejecución del análisis, lo que permitió la rápida determinación de la calidad de la materia prima. Conclusión. Se demostró que el método de cuantificación de fluconazol, validado por cromatografía líquida de alta resolución con detector de arreglo de diodos, es lo suficientemente selectivo, preciso, exacto, lineal y robusto; además, es capaz de generar resultados analíticos veraces en condiciones de uso reales, incluyendo el clima tropical de Colombia.

Introduction. The real laboratory conditions of each country, including climate, can affect the method's efficiency in analyzing a pharmacological substance. Thus, it is necessary to validate the process according to the corresponding guidelines and optimize it to ensure success and confidence in the results. Objective. The objective was to validate a methodology for fluconazole and its organic impurities quantification in raw material using high-performance liquid chromatography, with a diode array detector, under tropical climate conditions, and complying with all regulatory requirements. Materials and methods. We performed pre-validation tests of the method consisting of system adequacy, filters study, quantification limit, absence of systematic error, forced degradation studies, and solutions stability. In addition, we validated the specificity, linearity, accuracy, precision, and robustness of the system. Results. Separation of the degradation products from the analyte peaks allowed the achievement of the method's spectral purity. The solution's stability was not affected during the evaluated time (24 hours) at room temperature and under refrigeration. Linearity resulted in correlation coefficients greater than or equal to 0.999 for the evaluation and greater than or equal to 0.997 for impurities. We obtained a fluconazole recovery varying from 98 to 102% with an accuracy between 80 to 120% for impurities detection. The repeatability and reproducibility factor did not exceed a relative standard deviation of 2.0% for the evaluation and of 5.0% for the impurities, demonstrating the adequate robustness of the method. In addition, a short analysis execution time allowed the quick determination of the raw material quality. Conclusion. We demonstrated that the fluconazole quantification method validated by high-performance liquid chromatography is sufficiently selective, precise, exact, linear, and robust to generate accurate analytical results under real conditions, including the tropical climate of Colombia.

High-Throughput Ultra Performance Liquid Chromatography-Tandem Mass Spectrometry Method Validation for the Estimation of Atorvastatin and Active Metabolites in Human Plasma.

A highly selective, sensitive, rugged, and rapid ultra high-performance liquid chromatography-tandem mass spectrometry method (UPLC-MS/MS) is optimized and validated for reliable quantification of atorvastatin (ATR) and its active metabolites, 2-hydroxy atorvastatin (2-ATR) and 4-hydroxy atorvastatin (4-ATR) in human plasma using atorvastatin-D5 (ATR-D5), 2-hydroxy atorvastatin-D5 (2-ATR-D5), and 4-hydroxy atorvastatin-D5 (4-ATR-D5) as deuterium-labeled internal standards (ISTDs), respectively. Isocratic mode chromatographic separation was used with a reverse-phase C18 Symmetry Shield (150 × 4.6 mm, 5.0 µm) column and a mobile phase of acetonitrile:2 mM ammonium formate (pH-3.0) [65:35%v/v] at a flow rate of 0.7 mL/min. Electrospray ionization technique with positive ion mode polarity was applied to achieve the best signal intensity and stable response. Solid-phase extraction by direct elution method was applied to extract the drugs from the plasma sample. The calibration curve range was validated from a concentration range of 0.500-250 ng/mL for ATR and 2-ATR and 0.200-20 ng/mL for 4-ATR. The within-batch and between-batch precision and accuracy were found to be consistent and reproducible for all the analytes across the validation. Extraction recoveries were >80% for all analytes and ISTDs. All peaks of analytes and the respective ISTDs were eluted within 5.2 min. In this validated method, selective multivariate analytical approaches were utilized such as best fit linearity range for different strength formulations, preventive measures for in vivo and ex vivo autodegradation of metabolites, and shorter analysis time. This validated method can be useful for challenging quantification of ATR and its active metabolites for therapeutic drug monitoring and in high-throughput clinical study sample analysis.

Magnetic resonance spectroscopy and liquid chromatography-mass spectrometry metabolomics study may differentiate pre-eclampsia from gestational hypertension.

OBJECTIVE: To investigate the findings of magnetic resonance imaging (MRI), magnetic resonance spectroscopy (MRS), and serum metabolomics for differentiating pre-eclampsia (PE) from gestational hypertension (GH). METHODS: This prospective study enrolled 176 subjects including a primary cohort with healthy non-pregnant women (HN, n = 35), healthy pregnant women (HP, n = 20), GH (n = 27), and PE (n = 39) and a validation cohort with HP (n = 22), GH (n = 22), and PE (n = 11). T1 signal intensity index (T1SI), apparent diffusion coefficient (ADC) value, and the metabolites on MRS were compared. The differentiating performances of single and combined MRI and MRS parameters for PE were evaluated. Serum liquid chromatography-mass spectrometry (LC-MS) metabolomics was investigated by sparse projection to latent structures discriminant analysis. RESULTS: Increased T1SI, lactate/creatine (Lac/Cr), and glutamine and glutamate (Glx)/Cr and decreased ADC value and myo-inositol (mI)/Cr in basal ganglia were found in PE patients. T1SI, ADC, Lac/Cr, Glx/Cr, and mI/Cr yielded an area under the curves (AUC) of 0.90, 0.80, 0.94, 0.96, and 0.94 in the primary cohort, and of 0.87, 0.81, 0.91, 0.84, and 0.83 in the validation cohort, respectively. A combination of Lac/Cr, Glx/Cr, and mI/Cr yielded the highest AUC of 0.98 in the primary cohort and 0.97 in the validation cohort. Serum metabolomics analysis showed 12 differential metabolites, which are involved in pyruvate metabolism, alanine metabolism, glycolysis, gluconeogenesis, and glutamate metabolism. CONCLUSIONS: MRS is expected to be a noninvasive and effective tool for monitoring GH patients to avoid the development of PE. KEY POINTS: • Increased T1SI and decreased ADC value in the basal ganglia were found in PE patients than in GH patients. • Increased Lac/Cr and Glx/Cr, and decreased mI/Cr in the basal ganglia were found in PE patients than in GH patients. • LC-MS metabolomics showed that the major differential metabolic pathways between PE and GH were pyruvate metabolism, alanine metabolism, glycolysis, gluconeogenesis, and glutamate metabolism.

Development and validation of an LC-MS/MS method for the determination of 12 ceramides in human plasma / 中华检验医学杂志

Objective:To establish and validate a reliable and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the detection of 12 ceramides in human plasma.Methods:From October 2021 to October 2022, 438 apparently healthy individuals were enrolled in the Affiliated Hospitals of Zunyi Medical University for reference intervals of 12 ceramides in this population. Plasma samples were collected, and separated using the ACQUITY UPLC BEH C18 (2.1×50 mm, 1.7 μm) column, deuterated isotopes were used as internal standards. The mobile phase is water (containing 0.1% formic acid) and isopropanol: acetonitrile (1∶1, v/v, containing 0.1% formic acid) at a flow rate of 0.4 ml/min with gradient elution. The detection method was established using the Qlife Lab 9000 Plus triple quadrupole mass spectrometer. The performance of the method was evaluated in terms of linearity, the lower limit of quantification, precision, recovery, and stability.Results:The method passed the performance evaluation in terms of linearity, the lower limit of quantification, recovery, precision, and stability. The intra-and inter-batch precision of the 12 ceramides ranged from 1.3% to 14.3%, the correctness was verified by spiked recovery experiments, and the recoveries ranged from 91.9% to 111.0%. The lower limit of quantification ranged from 0.001 to 0.100 μmol/L. Standard curve showed good linearity (correlation coefficient r>0.990). Stability tests showed that the 12 ceramides were stable in the biological matrix and after processing under different conditions for a specified period of time. The corresponding biological reference intervals were established for each of the 12 ceramides: 0.103-0.326 μmol/L for Cer(d18∶1/16∶0), 0.018-0.098 μmol/L for Cer(d18∶1/18∶0), 0.933-3.919 μmol/L for Cer(d18∶1/24∶0), 0.243-1.072 μmol/L for Cer(d18∶1/24∶1), 0.001-0.007 μmol/L for Cer(d18∶1/14∶0), 0.022-0.095 μmol/L for Cer(d18∶1/20∶0), 0.185-0.835 μmol/L for Cer(d18∶1/22∶0), 0.003-0.022 μmol/L for Cer(d18∶0/16∶0), 0.001-0.016 μmol/L for Cer(d18∶0/18∶0), 0.017-0.156 μmol/L for Cer(d18∶0/24∶0), 0.008-0.074 μmol/L for Cer(d18∶0/24∶1), and 0.106-0.721 μmol/L for LacCer(d18∶1/24∶1). Conclusion:Our study shows that the newly established LC-MS/MS method for the determination of 12 ceramides in human plasma is reliable, and suitable for clinical application.

Establishing and evaluating a robust method based on LC-MS/MS for simultaneous determination of Aβ1-42,Aβ1-40 and A β1-38 in cerebrospinal fluid / 中华检验医学杂志

Objective:To establish and validate an LC-MS/MS method for simultaneous determination of Aβ 1-42, Aβ 1-40, and Aβ 1-38 in cerebrospinal fluid. Additionally, the consistency between this method and three mainstream detection methods was evaluated.Methods:This study involved method establishment, validation, and consistency evaluation. The N15 labeled β-amyloid protein was used as the internal standard. Extraction was performed using Waters MCX 96-wells solid phase extraction plate, and the eluent was collected to QuanRecovery MaxPeak 700 μl plate. At the positive ion mode, the multi-reaction ion monitoring mode based on electric spray ionization is chosen for the determination of CSF Aβ 1-42, Aβ 1-40, and Aβ 1-38. Referring to the CLSI C62-A and EP-15A3 guidelines, the method is evaluated and verified, including quantitation of limit (LOQ), linearity, recovery, precision, and accuracy. In addition, a total of 57 clinical residual CSF samples were collected and the concentrations of Aβ 1-42 and Aβ 1-40 were determined based on manual INNOTEST ELISA assay and Lumipulse G and Roche Elecsys fully automated biochemical analyzers. The comparison analysis and deviation evaluation were conducted by passing-bablok and Bland Altman methods.Results:The analysis time of this method is 8 min, and the LOQ of Aβ 1-42, Aβ1-40 and Aβ1-38 is 0.1 ng/ml, 0.5 ng/ml, and 0.1 ng/ml, respectively, and the linear range can meet the needs of clinical detection. Respectively, the recovery is 86.2%-93.8%, 100.9%-103.9% and 103.3%-107.1%; the total imprecision is 4.7%-7.4%, 3.5%-4.6% and 5.2%-10.9%. The measured values of Aβ 1-42 certified reference materials are all within the allowable uncertainty requirements. Moreover, the carryover rate of three analytes was all≤0.11%. In addition, the correlations of Aβ 1-42 and Aβ1-40 in CSF between this LC-MS/MS method and the INNOTEST ELISA method, Lumipulse G and Roche Elecsys fully automated biochemical analyzers were all deemed good, with correlation coefficient (r) ranging from 0.920 to 0.970. However, the measured values between the four methods were remarkably different.Conclusion:We established and validated a robust method based on LC-MS/MS technology for simultaneous determination of Aβ 1-42, Aβ 1-40, and Aβ 1-38 in CSF. The method is accurate, simple, and suitable for clinical measurements. However, despite good correlations, there were substantial differences in the measurement results of Aβ 1-42 and Aβ 1-40 among different analytical platforms, indicating the need for further promotion of harmonization and standardization processes for AD classic biomarkers.

Aldosterone Immunoassay-Specific Cutoff Value for Seated Saline Suppression Test for Diagnosing Primary Aldosteronism.

A seated saline loading test (SLT) using liquid chromatography-tandem mass spectrometry (LC-MS/MS) is one of the most accepted confirmatory tests of primary aldosteronism. However, LC-MS/MS is time-consuming and is not widely available in diagnostic laboratories compared to immunoassay. With immunoassay, it is unknown whether SLT in the seated position is more accurate than that of the supine position, and a cutoff value of post-seated SLT plasma aldosterone concentration (PAC) must be established in the Korean population. Ninety-eight patients underwent SLT in both positions, and post-SLT PAC was measured by LC-MS/MS and radioimmunoassay. We confirmed primary aldosteronism if post-seated SLT PAC by LC-MS/MS exceeded 5.8 ng/dL. The area under the receiver operating characteristic curve was greater for seated than supine SLT (0.928 vs. 0.834, P=0.003). The optimal cutoff value of post-seated SLT by radioimmunoassay was 6.6 ng/dL (sensitivity 83.3%, specificity 92.2%).

[Fast determination of bongkrekic acid in plasma by high performance liquid chromatography-tandem mass spectrometry].

Objective: To establish a method for rapid determination of bongkrekic acid (BA) in plasma by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Methods: In November 2020, plasma samples were extracted by methanol and acetonitrile (1∶1) and purified directly. The samples were separated by C18 column. Gradient elution was carried out with 5 mmol/L ammonium acetate water acetonitrile solution as mobile phase. Under the optimized instrument conditions, the electrospray ionization multiple reaction monitoring (MRM) mode was used, and the external standard method was used for quantitative analysis. Results: The linear relationship of BA in plasma was good in the concentration range of 2-100 µg/L, the correlation coefficient was 0.9998, the average recovery was 83.7%-112.0%, the relative standard deviation within and between batches was less than 10%, the detection limit of the method was 0.7 µg/L and the lower limit of quantification was 2.0 µg/L. Conclusion: The method is simple, rapid, accurate and sensitive, and can meet the requirements for the determination of BA in blood samples of poisoning patients.

Fast determination of bongkrekic acid in plasma by high performance liquid chromatography-tandem mass spectrometry / 中华劳动卫生职业病杂志

Objective: To establish a method for rapid determination of bongkrekic acid (BA) in plasma by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Methods: In November 2020, plasma samples were extracted by methanol and acetonitrile (1∶1) and purified directly. The samples were separated by C18 column. Gradient elution was carried out with 5 mmol/L ammonium acetate water acetonitrile solution as mobile phase. Under the optimized instrument conditions, the electrospray ionization multiple reaction monitoring (MRM) mode was used, and the external standard method was used for quantitative analysis. Results: The linear relationship of BA in plasma was good in the concentration range of 2-100 μg/L, the correlation coefficient was 0.9998, the average recovery was 83.7%-112.0%, the relative standard deviation within and between batches was less than 10%, the detection limit of the method was 0.7 μg/L and the lower limit of quantification was 2.0 μg/L. Conclusion: The method is simple, rapid, accurate and sensitive, and can meet the requirements for the determination of BA in blood samples of poisoning patients.

Purificação da imunoglobulina M a partir da utilização de frações do plasma humano empregando técnicas de cromatografia líquida

Immunoglobulin M (IgM) is a pentamer of approximately 950kDa, consisting of two heavy chains of 75kDa each, two light chains of 25kDa and a J chain of 15kDa. IgM is a promising therapeutic candidate due to increasing evidence suggesting its potential as a tumor marker, anti-inflammatory and immunomodulatory activities. In order to exploit its full potential, it is important that large amounts of IgM are available at low cost. In this work, two purification steps that were already being developed by the laboratory were explored. Purification by metal affinity chromatography (IMAC) and cation exchange of the pool from plasma purification on Sepharose 4FF followed by ANX Sepharose FF was evaluated. In IMAC, the purification was evaluated at pHs 5.0, 6.0 and 7.0 and the results indicate that with pH 6.0 in IMAC-Co2+ we obtained IgM with better recovery and greater purity. By varying the NaCl concentration in the equilibrium buffer between 250mM and 500mM, we found that IgM was obtained with greater purity in the purification in which 250mM NaCl was used in the equilibrium buffer. Using the cation exchange column, the results obtained were not satisfactory. The purity of IgM, calculated by the ImageJ program, was approximately 75%. To increase the purity of IgM, purification on the Superdex 200 gel filtration column will be evaluated.

A imunoglobulina M é um pentâmero de aproximadamente 950kDa, sendo composto por duas cadeias pesadas de 75kDa cada, duas cadeias leves de 25kDa e uma cadeia J de 15kDa. IgM é um candidato terapêutico promissor devido ao aumento de evidências que sugerem seu potencial de marcador tumoral, atividades anti-inflamatória e imunomoduladoras. Com o intuito de que todo seu potencial seja explorado, é importante que grandes quantidades de IgM estejam disponíveis a baixo custo. Nesse trabalho foram exploradas duas etapas de purificação que já estavam sendo desenvolvida pelo laboratório. Aplicou-se cromatografia de afinidade ao metal (IMAC) na fração 350mM proveniente da ANX Sepharose FF, com o intuito de obter IgM com alto grau de pureza. Foi observado que a melhor faixa de trabalho foi em pH 6,0 utilizando como metal imobilizado o cobalto e solução contendo NaCl 250mM. Como segunda estratégia, aplicou-se cromatografia de troca catiônica na fração 350mM diluído 10 vezes com água purificada e ao contrário da IMAC, não obtivemos resultados satisfatórios em relação a pureza de IgM. Apesar dos resultados alcançados, ainda é necessário o desenvolvimento de novas estratégias e estudos para o aumento de IgM, a fim de se obter uma imunoglobulina mais pura para possível uso terapêutico.

Correlation between serum IgG N-glycan and Lauren classification of gastric cancer / 中华检验医学杂志

Objective:Analyze the correlation between serum immunoglobulin G (IgG) N-glycan and Lauren classification of gastric cancer.Methods:A retrospective study was performed on 17 patients with diffuse type gastric cancer and 21 patients with intestinal type who received treatment in Zhongshan Hospital from 2017 to 2018, and the general medical history data and disease characteristics were summarized. The serum IgG glycome profiles were analyzed by ultraperformance liquid chromatography, and the difference between intestinal type and diffuse type gastric cance was compared.Logistic regression was used to evaluate the correlation between serum IgG N-glycan and Lauren classification.Results:IgG N-glycome analysis included 27 directly detected glycans and 4 derived traits. H=Hexose, N=N-acetylglucosamine, F=Fucose, S=Sialic acid.There was no significant difference in IgG N-glycan among different chemotherapy protocol. Compared with intestinal type, H3N3F1 ( t=3.785, P=0.001), H3N4( t=3.919, P=0.002), H3N4F1( t=2.770, P=0.005), H3N5F1( t=2.888, P=0.010) were decreased in diffuse type; H4N4F1(6)( t=?3.488, P<0.001), H5N4F1( t=?3.401, P=0.003), H5N5F1( t=?2.303, P=0.023), H5N4F1S1 ( t=?3.068, P=0.008) were increased.H3N3F1( OR:1.20, P=0.008), H3N4( OR:1.32, P=0.005), H3N4F1 ( OR:1.13, P=0.017), H3N5F1 ( OR:1.78, P=0.015), H4N4F1(6)( OR:0.43, P=0.008), H5N4F1(6)( OR:0.74, P=0.008), H5N5F1 ( OR:0.32, P=0.036), H5N4F1S1( OR:0.48, P=0.009) were significantly correlated with Lauren classification. Sialylated ( t=?2.717, P=0.012) and galactosylated ( t=?3.400, P=0.001) IgG N-glycan were reduced in patients with intestinal type gastric cancer.Galactosylated ( OR:0.87, P=0.007) and sialylated ( OR:0.62, P=0.015) IgG N-glycan were significantly correlated with Lauren classification. Conclusion:Some IgG N-glycan are significantly correlated with Lauren classification, which can be used as potential biomarkers.

Potential biomarkers for the diagnosis and differential diagnosis of immune-mediated demyelinating diseases screened by tandem mass spectrometry technology / 中华检验医学杂志

Objective:To screen the potential biomarkers for the diagnosis and differential diagnosis of immune-mediated demyelinating diseases by tandem mass tags (TMT) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) technology.Methods:Twenty patients with demyelinating diseases (demyelinating group) and 10 patients with noninflammatory neurological diseases (NND group) from Beijing Tiantan Hospital affiliated to Capital Medical University from January 2020 to January 2021 were enrolled in this study. The demyelinating group included 10 patients with Guillain-Barre syndrome (GBS subgroup) and 10 patients with multiple sclerosis (MS subgroup). TMT proteomics was used to screen out the different protein expression patterns between the demyelinating group and the NND group and between the GBS subgroup and the MS subgroup (difference>2 or<0.5 and with statistical significance), and String database was used to perform gene ontology (GO) analysis and Kyoto encyclopedia of gene and genomes (KEGG) analysis on the pathways involved in the differently expressed proteins between the groups. In addition, 80 demyelinating patients (demyelinating diseases validation group) and 40 healthy subjects (healthy control group) were selected for retrospective analysis of general lipid indexes. The demyelinating diseases validation group included 40 GBS patients (GBS validation group) and 40 MS patients (MS validation group). Receiver operating characteristic (ROC) curve was obtained to evaluate the value of general lipid indexes for the diagnosis of demyelinating diseases and the differential diagnosis between GBS and MS groups.Results:A total of 362 proteins were detected by TMT proteomics. There were 101 differentially expressed proteins between the demyelinating group and the NND group, and 45 differentially expressed proteins between the GBS group and the MS group. Compared with the NND group, GO enrichment analysis showed that the top five enrichment pathways in the demyelinating group were macrophage colony stimulating factor and receptor complex, negative regulation of cholesterol input, negative regulation of very low density lipoprotein particle clearance, triglyceride-rich lipoprotein particle remodeling, and cholesterol reverse transport. Compared with MS group, the top five enriched pathways in GBS group were high-density lipoprotein particle receptor binding, negative regulation of very low density lipoprotein particle remodeling, negative regulation of cholesterol input, negative regulation of very low density lipoprotein particle clearance, and medium density lipoprotein particle. KEGG enrichment analysis results showed that differentially expressed proteins in the demyelinating group and the NND group were enriched in 8 pathways, including phosphatidylinositide 3-kinases-protein kinase B signaling pathway, complement and coagulation cascade reaction, extracellular matrix and its receptor interaction, Staphylococcus aureus infection, cholesterol metabolism, RAS signaling pathway, phagosome, and mitogen-activated protein kinase signaling pathway. Differentially expressed proteins in GBS group and MS group were enriched in 9 pathways: cholesterol metabolism, complement and coagulation cascade, platelet activation, peroxisome proliferators-activated receptors signaling pathway, vitamin digestion and absorption, novel coronavirus infection, fat digestion and absorption, axon guidance, and neutrophil extracellular trap formation pathway. The levels of triglyceride (TG), total cholesterol (TC), low density lipoprotein cholesterol (LDL-C) and apolipoprotein B (apoB) were significantly higher, while high density lipoprotein cholesterol (HDL-C) and apolipoprotein A1 (apoA1) levels were significantly lower in the demyelinating disease validation group than in the healthy control group (all P<0.05 or 0.01). Area under the curve (AUC) of TG, TC, HDL-C, LDL-C, apoA1 and apoB alone or in combination for the diagnosis of immune-mediated demyelinating diseases was 0.746, 0.643, 0.798, 0.703, 0.806, 0.708 and 0.868, respectively. The AUC of HDL-C, apoA1, LDL-C and apoB for differential diagnosis between GBS and MS was 0.692, 0.653, 0.632, 0.695 and 0.718, respectively. Conclusions:There are differences in cerebrospinal fluid proteomics between patients with immune-mediated demyelinating disease and patients with NND, GBS and MS, and the differentially expressed protein patterns mainly exist in the pathways related to lipid metabolism. Lipid related indicators may be used as biomarkers for the diagnosis and differential diagnosis of immune-mediated demyelinating disease.

Simultaneous determination of related substances in entecavir film-coated tablet by high performance liquid chromatography.

: To establish a high performance liquid chromatography method to simultaneously quantify eight related substances in entecavir film-coated tablets.According to USP40 and YBH33292005 standards, a high performance liquid chromatography (HPLC) method for simultaneous determination of 8 related substance in entecavir film-coated tablets was established and validated. The column was WATERS C18 (250 mm the mobile phase A was water-acetonitrile-trifluoroacetic acid (990∶10∶1), the mobile phase B was water-acetonitrile-trifluoroacetic acid (700∶300∶1) with gradient elution and ultraviolet-visible light detector, detection wavelength at 254 nm and column temperature of The resolution between entecavir and each impurity peak was more than 1.5, and each impurity had a good linear relationship with the peak area in the linear range. The limits of detection and quantification, precision, stability, durability, specificity, met the verification requirements. The HPLC method established in this study can be used for simultaneous determination of 8 related substance in entecavir film-coated tablets.

[Metabolomics study of urine with Benzene, Toluene and Xylene combined exposure based on ultra performance liquid chromatography-quadrupole time-of-flight mass spectrometry].

Objective: To study the effects of combined occupational exposure of benzene, toluene, and xylene on human metabolism at an overall level, and to screen biomarkers related to the combined occupational exposure of benzene, toluene, and xylene, and to explore the mechanism of early health effects preliminarily caused by combined occupational exposure of benzene, toluene, and xylene by identification of biomarkers and retrieval of metabolic pathways. Methods: A shoe-making company was selected as the research site. Twenty subjects for the exposed group and the control group were selected separately, and urine of the subjects was collected. The metabolic profiles of the samples were collected by liquid chromatography time-of-flight mass spectrometry, and professional metabolomics and multivariate statistical analysis software were used to establish PCA and OPLS-DA analysis models to screen potential biomarkers and identify biomarkers. Finally, based on the dynamic changes and trends of potential biomarkers between groups, the mechanism of body damage caused by benzene, toluene, and xylene was initially explored. Results: Urine metabolomics analysis showed that the metabolic profile of urine samples of the benzene, toluene, and xylene combined exposure group was different from that of the control group. 27 potential biomarkers that were closely related to the combined exposure of benzene, toluene, and xylene were screened and identified. These potential biomarkers were enriched in 16 metabolic pathways, of which 3 pathways were significantly enriched (P<0.05) , respectively, lysine metabolism, amino sugar metabolism, and nucleotide sugar metabolism. Conclusion: The metabonomics method can well reflect the changes in the metabolome of urine samples in the occupational population after the combined exposure of benzene, toluene, and xylene, which will help us better evaluate the risk of combined exposure of benzene, toluene, and xylene and prevent and control their health risks.

Achieving optimal adherence to medical therapy by telehealth: Findings from the ORBITA medication adherence sub-study.

INTRODUCTION: The ORBITA trial of percutaneous coronary intervention (PCI) versus a placebo procedure for patients with stable angina was conducted across six sites in the United Kingdom via home monitoring and telephone consultations. Patients underwent detailed assessment of medication adherence which allowed us to measure the efficacy of the implementation of the optimization protocol and interpretation of the main trial endpoints. METHODS: Prescribing data were collected throughout the trial. Self-reported adherence was assessed, and urine samples collected at pre-randomization and at follow-up for direct assessment of adherence using high-performance liquid chromatography with tandem mass spectrometry (HPLC MS/MS). RESULTS: Self-reported adherence was >96% for all drugs in both treatment groups at both stages. The percentage of samples in which drug was detected at pre-randomization and at follow-up in the PCI versus placebo groups respectively was: clopidogrel, 96% versus 90% and 98% versus 94%; atorvastatin, 95% versus 92% and 92% versus 91%; perindopril, 95% versus 97% and 85% versus 100%; bisoprolol, 98% versus 99% and 96% versus 97%; amlodipine, 99% versus 99% and 94% versus 96%; nicorandil, 98% versus 96% and 94% versus 92%; ivabradine, 100% versus 100% and 100% versus 100%; and ranolazine, 100% versus 100% and 100% versus 100%. CONCLUSIONS: Adherence levels were high throughout the study when quantified by self-reporting methods and similarly high proportions of drug were detected by urinary assay. The results indicate successful implementation of the optimization protocol delivered by telephone, an approach that could serve as a model for treatment of chronic conditions, particularly as consultations are increasingly conducted online.

Global DNA (hydroxy)methylation is stable over time under several storage conditions and temperatures.

BACKGROUND: Epigenetic markers are often quantified and related to disease in stored samples. While, effects of storage on stability of these markers have not been thoroughly examined. In this longitudinal study, we investigated the influence of storage time, material, temperature, and freeze-thaw cycles on stability of global DNA (hydroxy)methylation. METHODS: EDTA blood was collected from 90 individuals. Blood (n = 30, group 1) and extracted DNA (n = 30, group 2) were stored at 4°C, -20°C and -80°C for 0, 1 (endpoint blood 4°C), 6, 12 or 18 months. Additionally, freeze-thaw cycles of blood and DNA samples (n = 30, group 3) were performed over three days. Global DNA methylation and hydroxymethylation (mean ± SD) were quantified using liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) with between-run precision of 2.8% (methylation) and 6.3% (hydroxymethylation). Effects on stability were assessed using linear mixed models. RESULTS: global DNA methylation was stable over 18 months in blood at -20°C and -80°C and DNA at 4°C and -80°C. However, at 18 months DNA methylation from DNA stored at -20°C relatively decreased -6.1% compared to baseline. Global DNA hydroxymethylation was more stable in DNA samples compared to blood, independent of temperature (p = 0.0131). Stability of global DNA methylation and hydroxymethylation was not affected up to three freeze - thaw cycles. CONCLUSION: Global DNA methylation and hydroxymethylation stored as blood and DNA can be used for epigenetic studies. The relevance of  small differences occuring during storage depend on the expected effect size and research question.

Determination of formononetin and harmful elements of heavy metals in Jinji Pill / 国际中医中药杂志

Objective:To use the high performance liquid chromatography method to determine the content of formononetin in Jinji Pills and by using atomic absorption spectrophotometry,method to determine the harmful elements of heavy metal in Jinji Pills in orer to provide the scientific foundation for improving its quality standards and safety evaluation. Methods:Use Waters XBridge? C18 column (4.6 mm × 250 mm, 5 μm), set mobile phase at acetonitrile-1% phosphoric acid solution (27:73), flow rate 1.0 ml/min, column temperature 30 ℃, detection wavelength 249 nm, column temperature 30 ℃; Lead (Pb) and cadmium (Cd) was detected by graphite furnace method; arsenic (As) was detected by cold steam series graphite furnace method; copper (Cu) was detected by flame method; mercury (Hg) was detected by cold steam method.Results:The formononetin had a good linear relationship between 0.02-2.01 μg, the recovery rate was 98.5%, RSD was 1.53%. Lead (Pb) recovery rate was 103.6%, cadmium (Cd) recovery rate was 95.7%, arsenic (As) recovery rate was 92.4%, mercury (Hg) recovery rate was 104.9%, copper (Cu) recovery rate was 112.5%. Conclusion:This method is of accuracy, specificity, high sensitivity and good reproducibility, which could provide strong evidence for quality improvement and safety use of Jinji pill.

Application of large volume injection for sensitive LC-MS/MS analysis of seven artificial sweeteners in surface waters.

The combination of large volume injection and mixed-mode chromatography was performed for direct ultra-trace LC-MS/MS analysis of seven artificial sweeteners with varying physicochemical properties in surface water samples.•The injection volume was raised from 10 µL to 500 µL, while the overall analysis time was only increased by ≈5 min compared to the initial method.•Online column head refocusing and concentration of analytes enabled detection in sub-ng L-1 concentration range without elaborate sample preparation steps.•Relative standard deviations <7% despite multiple injection into the loop.

Development and validation of a specific and sensitive liquid chromatography tandem mass spectrometry method for determination of tetrodotoxin in human urine and its pharmacokinetic study.

Tetrodotoxin (TTX) exhibits the therapeutic potential in blocking pain and in low doses can safely relieve severe pain. The urinary excretion profiles of TTX in humans have not been reported due to the extremely low lethal dose. In this study, a rapid and specific method based on protein precipitation coupled to liquid chromatography tandem mass spectrometry was developed to determine the level of TTX in human urine samples. 11-Deoxytetrodotoxin was used as an internal standard (IS). Multiple reaction monitoring mode was used for quantification using target fragment ions m/z 320.0 → 162.1 for TTX and m/z 304.0 → 176.0 for 11-deoxyTTX. The separation of analytes was achieved on a hydrophilic interaction liquid chromatography column (250 × 4.6 mm, 5.0 µm). The mobile phase consisted of 5 mM ammonium formate in water (pH = 4.50) and 5 mM ammonium formate in acetonitrile (pH = 4.50). The flow rate was set at 0.80 mL/min in a gradient condition. Calibration plots were linear throughout the range 0.986-98.6 ng/mL of TTX in human urine. The intra-assay accuracies and precisions were within the acceptable range. The method was successfully applied to a urinary excretion study after intravenous administration of TTX to healthy volunteers. The developed method will be helpful for future pharmacological studies of TTX.

Rapid Determination of 13 Sedative Substances and Their Metabolites in Blood by LC-MS/MS.

ABSTRACT: Objective To establish an analysis method for simultaneous determination of 13 sedative substances and their metabolites in blood by liquid-liquid extraction and liquid chromatography-tandem mass spectrometry （LC-MS/MS） technology and to apply the method to actual cases. Methods The samples were extracted with ethyl acetate after an internal standard was added. The extract was condensed until it was nearly dry and then its residues were dissolved with methanol, filtered through 0.22 µm filter and finally determined. The 13 sedative substances and their metabolites were separated through the C18 chromatographic column, then gradient elution was performed on them with methanol and 20 mmol/L ammonium formate （containing 0.1% formic acid） solution. After that, they were determined in the electrospray positive ion mode and quantified by internal standard method. Results The 13 sedative substances and their metabolites in blood showed good linearity in the range of 5-200 µg/L with correlation coefficients ranging from 0.990 3 to 0.999 8. The detection limits were 0.1-1.0 µg/L. Recovery rates of sedative substances were in the range of 71.2%-93.4% when solutions with concentrations of 10, 50 and 200 µg/L were added. The deviations of intra-day and inter-day relative standard deviations （RSD） were not more than 8.6%. Accuracies （bias） were within ±9.8%. Conclusion This method is rapid, simple, effective and sensitive, and can be applied to analysis of 13 sedative substances and their metabolites in blood in forensic toxicology.