Objective:To develop and validate a liquid chromatography-tandem mass spectrometry method for determining levofloxacin in plasma sample from pediatric patients.Method:This is a prospective, observational study. The clinical residual plasma samples from healthy individuals for physical examination in Children's Hospital Affiliated to Zhengzhou University were collected as blank matrix. Plasma samples from five pediatric patients who did not receive levofloxacin or ciprofloxacin in the department of Respiration were collected for methodological evaluation. In addition, 34 clinical plasma samples from 22 pediatric patients (9 males and 13 females; mean age (8.1±3.7) years) using levofloxacin was collected, and their plasma concentrations were determined. Using ciprofloxacin as the internal standard, levofloxacin in plasma samples was quantified by liquid chromatography-tandem mass spectrometry following protein precipitation using acetonitrile. A C18 column (Shim-pac GIST-HP C18, 2.1 mm×100 mm, 3 μm) and mobile phase composed of water (containing 0.1% formic acid) and acetonitrile (containing 0.1% formic acid) with gradient elution at a flow rate of 0.4 ml/min were used to separate levofloxacin. The column temperature was 40 ℃, injection volume was 1 μl and the total analysis time was 9 min. Levofloxacin and ciprofloxacin were ionized with an ESI source in positive ion mode and detected in multiple reaction monitoring (MRM) mode. The detected ions of levofloxacin and ciprofloxacin were m/z 362.10→318.1 and 332.15→231.05, respectively. The method′s specificity, sensitivity, linearity, precision, accuracy, recovery rate, stability, matrix effect, and carry-over were validated. All statistical analyses were performed with SPSS statistical software (version 17.0). The normality of the data was detected by the K-S test. A P<0.05 was considered statistically significant for two tailed tests. Results:The LC-MS/MS method showed a good linearity within the range of 0.062 5-20 mg/L, with the lower detection limit of levofloxacin of 0.062 5 mg/L. The calibration curve for levofloxacin was Y=0.093X+0.010 ( R2>0.99). Under different quality control levels, the accuracy ranged from 92.57% to 104.39%, and the intra-day and inter-day imprecision ranged from 2.32% to 9.35%. These values were not affected by the normal matrix, 5% hemolysis matrix and 15% hyperlipidemia matrix. Furthermore, the levofloxacin plasma samples were stable in the short term. A total of 34 plasma samples from 22 patients were collected and analyzed. Only 2 plasma samples were below the lower limit of quantification, while the other plasma concentrations of levofloxacin were ranged from 0.091 to 6.755 mg/L. Cmax was (5.52 ± 1.09) mg/L. Conclusion:The LC-MS/MS method meets the requirements of the reference method and requires a small sample size (50 μl), making it suitable for the determination of levofloxacin in plasma from pediatric patients.

Objective To investigate the molecular mechanism of Shema Zhichuan Liquid in the treatment of neutrophilic asthma(NA)based on network pharmacology and in vivo experiments.Methods(1)The TCMSP,literature search and Swiss ADME and Swiss Target Prediction databases were used to search and screen the active components and their targets of Shema Zhichuan Liquid.OMIM,GeneCards,DisGeNET and DrugBank databases were used to search and screen NA disease-related targets.The intersection of the active components and NA disease-related targets of Shema Zhichuan Liquid was obtained through the microbiology platform to obtain the potential targets of Shema Zhichuan Liquid for the treatment of NA(common targets).Cytoscape 3.8 software was used to construct the network of"Chinese medicinals-active components-potential targets".The PPI network of potential targets was established by STRING database,and the core targets were obtained by analysing the built-in Mcode plug-in.The Metascape platform was used to enrich the gene ontology(GO),Kyoto Encyclopaedia of Genes and Genomes(KEGG)pathways for the potential targets.(2)BALB/C mice were acclimatised and fed for 1 week and randomly divided into a blank group,NA model group,low-dose group(2.5 g·kg-1)and high-dose group of Shema Zhichuan Liquid(10 g·kg-1),and control group of Dexamethasone(1 mg·kg-1);the NA mouse model was replicated by intraperitoneal injection of sensitizer(OVA+CFA)and nebulized inhalation excitation.OVA/CFA(20 μg OVA+75 μg CFA,0.3 mL)was injected intraperitoneally to sensitize on days 0,7 and 14 respectively,and 5%OVA suspension was nebulized on days 21-30(8 mL each time,40 minutes each time,once a day);1 hour before nebulisation,each group was administered by gastric gavage,and the Dexamethasone control group was administered by intraperitoneal injection once a day.The pathological changes of mouse lung tissue were observed by HE staining;IL-8 content in alveolar lavage fluid was detected by ELISA;mRNA expression levels of NLRP3 and CXCR2 were detected by RT-qPCR;and p-mTOR protein expression levels was detected by immunohistochemistry.Results(1)A total of 826 active component targets and 154 NA disease-related targets were obtained,and 51 potential targets(common targets)for the treatment of NA were obtained from the intersection of the active component and the NA disease-related targets of Shema Zhichuan Liquid.Through the network analysis of"Chinese medicinals-active components-potential targets",quercetin,lignocerotoxin,kaempferol,stigmasterol,naringenin and other key active components were obtained.The PPI network analysis of potential targets yielded 29 core targets,including AKT1,IL6,TNF,EGFR,NLRP3,RELA,MIF,CXCR2,VEGFA,etc..The GO functional enrichment analysis yielded 882 biological process entries,33 cellular component entries,and 61 molecular function entries;KEGG analysis yielded 142 signaling pathways,mainly involving TNF signaling pathway,influenza A signaling pathway,Toll-like receptor pathway,MAPK signaling pathway,mTOR signaling pathway and so on.(2)Results of animal experiments:compared with the blank group,mice in the NA model group showed obvious damage to the airway mucosa,structural disorders,a large number of inflammatory cells infiltration,mucosal congestion,oedema,obvious thickening of the alveolar wall,and narrowing of the alveolar lumen;the level of the inflammatory factor IL-8 in the alveolar lavage fluid was significantly elevated(P＜0.05);the mRNA expressions of NLRP3 and CXCR2 in the lung tissues of the mice were significantly up-regulated(P＜0.01),and the protein expression of p-mTOR was significantly increased.Compared with the NA model group,the structural arrangement of bronchial epithelial cells in the mice in the low-and high-dose groups of Shema Zhichuan Liquid was slightly disordered,with a small amount of inflammatory cell infiltration around the airways and blood vessels,and the congestion and edema of the bronchial mucosa were significantly reduced;the mRNA expression of CXCR2 in the lung tissues of the mice was significantly down-regulated(P＜0.01),and the level of expression of p-mTOR protein was significantly reduced.The IL-8 level in the vesicular lavage fluid of mice in the high-dose group was significantly reduced(P＜0.05);the mRNA expression of NLRP3 in the lung tissue of mice in the low-dose group was significantly down-regulated(P＜0.05).Conclusion The therapeutic effect of Shema Zhichuan Liquid on NA may be achieved through the key active components,such as quercetin,lignocerol and kaempferol,acting on the core targets,such as NLRP3 and CXCR2,and regulating the key signaling pathways,such as the TNF signaling pathway,the MAPK signaling pathway,the Toll-like signaling pathway,and the mTOR pathway.

Objective: To investigate the role of long non-coding RNA double homeobox A pseudogene 9 (DUXAP9) in head and neck squamous cell carcinoma (HNSCC) and to evaluate the expression level, molecular function and mechanism of DUXAP9 in HNSCC cells. Methods: Differential expression of lncRNAs between normal and tumor tissues in HNSCC tissues were screened using lncRNA microarray, the expression level of DUXAP9 in HNSCC tissues and its relationship with prognosis were analyzed in the TCGA database. The expression levels of DUXAP9 in HNSCC tissues and cell lines were detected using qRT-PCR. The function in HNSCC cells after DUXAP9 silencing was evaluated using the CCK-8 assay, wound healing assay, Transwell migration assay and subcutaneous xenograft assay in nude mice. Changes in the transcription and translation of epithelial-mesenchymal transition (EMT)-related proteins in head and neck squamous cell carcinoma cells after DUXAP9 silencing were detected using qRT-PCR and Western blot. Results: lncRNA microarray results showed that, compared to adjacent normal tissues, DUXAP9 was abnormally upregulated in HNSCC tissues. Analysis from TCGA database showed that, compared to HNSCC patients with low DUXAP9 expression, HNSCC patients with high DUXAP9 expression had poorer survival. The relative expression of DUXAP9 in HNSCC tissues and 4 HNSCC cell lines increased compared to paired adjacent normal tissues as detected using qRT-PCR. Silencing DUXAP9 significantly inhibited the proliferation, migration and expression of EMT-related genes in HNSCC cells. The silencing of DUXAP9 significantly inhibited subcutaneous tumorigenesis of the HNSCC cell line CAL27 in nude mice. Conclusion Silencing DUXAP9 significantly inhibited the proliferation of HNSCC cells and subcutaneous xenografts in nude mice. DUXAP9 may mediate the migration of head and neck squamous cell carcinoma cells via the EMT pathway.