MicroRNA-5195-3p mediated malignant biological behaviour of insulin-resistant liver cancer cells via SOX9 and TPM4.

BACKGROUND: Primary liver cancer is a malignant tumour of the digestive system, ranking second in cancer mortality in China. In different types of cancer, such as liver cancer, microRNAs (miRNAs) have been shown to be dysregulated. However, little is known about the role of miR-5195-3p in insulin-resistant liver cancer. METHODS AND RESULTS: In this study, in vitro and in vivo experiments were conducted to identify the altered biological behaviour of insulin-resistant hepatoma cells (HepG2/IR), and we proved that HepG2/IR cells had stronger malignant biological behaviour. Functional experiments showed that enhanced expression of miR-5195-3p could inhibit the proliferation, migration, invasion, epithelial-mesenchymal transition (EMT) and chemoresistance of HepG2/IR cells, while impaired expression of miR-5195-3p in HepG2 cells resulted in the opposite effects. Bioinformatics prediction and dual luciferase reporter gene assays proved that SOX9 and TPM4 were the target genes of miR-5195-3p in hepatoma cells. CONCLUSIONS: In conclusion, our study demonstrated that miR-5195-3p plays a critical role in insulin-resistant hepatoma cells and might be a potential therapeutic target for liver cancer.

Value of biomarkers in epithelial-mesenchymal transition models of liver cancer under different interventions: a meta-analysis.

Aim: A meta-analysis was conducted to evaluate the effectiveness of crucial biomarkers in HepG2 cells during epithelial-mesenchymal transformation induced by multiple interventions. Methods: PubMed, Web of Science, Embase, China National Knowledge Infrastructure, Chinese Biomedical Literature Database, Wan Fang Data and VIP databases were systematically searched from inception to 14 June 2020, by two independent reviewers. Results: A total of 58 studies were included in the meta-analysis. E-cadherin, N-cadherin and vimentin performed well under medicinal interventions. E-cadherin worked well under genetic interventions. E-cadherin and N-cadherin also performed significantly well under tumor microenvironment interventions. Under ncRNA interventions, the expression of E-cadherin significantly changed. Conclusion: Different sets of biomarkers should be selected under various interventions based on their performance.

LIGHT (TNFSF14) inhibits glucose uptake of adipocytes by downregulating GLUT4 expression via AKT signaling pathway.

Glucose homeostasis of adipocytes could be regulated by immune-adipose crosstalk. In order to investigate the effects of Lymphotoxin-like inducible protein that competes with glycoprotein D for herpesvirus entry on T cells (LIGHT) on glucose metabolism, we performed the present study. Our results showed that LIGHT deficiency improved glucose tolerance and enhanced glucose consumption of inguinal white adipose tissue (iWAT) under high fat diet. Consistently, Light overexpression could inhibit glucose uptake during the process of white adipogenesis. Mechanistically, LIGHT interacted with lymphotoxin-ß receptor (LTßR) to attenuate AKT pathway leading to downregulation of glucose transporter-4 (GLUT4) expression, which resulted in glucose uptake inhibition. In summary, our findings revealed LIGHT-LTßR-AKT-GLUT4 axis as a regulator of glucose uptake in adipose tissue, which suggested the pivotal role of LIGHT in maintaining glucose homeostasis.

Evaluation of toxoplasmosis in pregnant women using dot-immunogold-silver staining with recombinant Toxoplasma gondii peroxiredoxin protein.

BACKGROUND: Toxoplasma gondii infection endangers human health and affects animal husbandry. Serological detection is the main method used for epidemiological investigations and diagnosis of toxoplasmosis. The key to effective diagnosis of toxoplasmosis is the use of a standardized antigen and a specific and sensitive detection method. Peroxiredoxin is an antigenic protein and vaccine candidate antigen of T. gondii that has not yet been exploited for diagnostic application. METHODS: In this study, recombinant T. gondii peroxiredoxin protein (rTgPrx) was prepared and used in dot-immunogold-silver staining (Dot-IGSS) to detect IgG antibodies in serum from mice and pregnant women. The rTgPrx-Dot-IGSS method was established and optimized using mouse serum. Furthermore, serum samples from pregnant women were analyzed by rTgPrx-Dot-IGSS. RESULTS: Forty serum samples from mice infected with T. gondii and twenty negative serum samples were analyzed. The sensitivity and specificity of rTgPrx-Dot-IGSS were 97.5 and 100%, respectively, equivalent to those of a commercial ELISA kit for anti-Toxoplasma IgG antibody. Furthermore, 540 serum samples from pregnant women were screened with a commercial ELISA kit. Eighty-three positive and 60 negative serum samples were analyzed by rTgPrx-Dot-IGSS. The positive rate was 95.18%, comparable to that obtained with the commercial ELISA kit. CONCLUSIONS: The Dot-IGSS method with rTgPrx as an antigen might be useful for diagnosing T. gondii infection in individuals.

Global Analysis of miRNA Signature Differentially Expressed in Insulin-resistant Human Hepatocellular Carcinoma Cell Line.

Chemoresistance mediated by insulin resistance (IR) in HCC has already been validated. However, the underlying mechanism, especially the involvement of microRNAs (miRNAs) was unelucidated. In this study, miRNA microarrays and bioinformatics methods were employed to determine the dysregulation of miRNA by IR in HCC cells, and quantitative RT-PCR (qRT-PCR) was applied to valid the miRNA array data. Of all the 2006 miRNAs screened, 32 miRNAs were found up or down regulated between the HepG2/IR cells and its parental cells. Further literature mining revealed that some of these miRNAs may function as oncogenes or tumor suppressors that contribute to tumor progression, recurrence, and metastasis which eventually lead to chemotherapeutic resistance. Interestingly, bioinformatics analysis by Gene Ontology (GO) enrichment pathway indicating that function of the predicted target genes of these dysregulated miRNAs were significantly enriched in the processes related with biosynthesis, catabolism, modification etc., and Kyoto Encyclopedia of Genes and Genomes (KEGG) mapping showed that the biological regulatory mechanisms were integrated in cancer-related pathways. Moreover, we also constructed a network which connected the differentially expressed miRNAs to target genes, GO enrichments and KEGG pathways to reveal the hub miRNAs, genes and pathways. Collectively, our present study demonstrated the possible miRNAs and predicted target genes involving in the pathophysiology of insulin resistant HCC, providing novel insights into the molecular mechanisms of multidrug resistance in the insulin resistant HepG2 cells.

Influences of operating parameters on liquefaction performances of Tetra Pak in sub-/supercritical water.

Liquefaction performances of waste Tetra Pak in sub-/supercritical water were evaluated in micro-batch reactors. The influences of temperature (300-420 °C), pressure (16-24 MPa), residence time (5-60 min) and feed concentration (5-40 wt%) on bio-oil yield, high heating value (HHV), and functional groups in bio-oil were investigated. The results showed that bio-oil yield firstly increased with increasing temperature and then decreased when the temperature exceeded 360 °C. Reaction time longer than 30 min gave a negative effect on bio-oil yield. The influence of pressure on bio-oil yield increased markedly from 16 MPa to 22 MPa, and then stabilized. The feed concentration higher than 20 wt% showed little influence on bio-oil yield. Maximum bio-oil yield of 35.55% was found at 360 °C, 22 MPa, 30 min and feed concentration of 20 wt%. HHV and energy recovery efficiency increased significantly with temperature, and maximum HHV of 48.747 MJ/kg and energy recovery efficiency of 46.49% were found at 420 °C, 20 MPa, 30 min and feed concentration of 20 wt%. The main compounds in bio-oil and morphology of the solid residue were also analyzed, and the possible liquefaction pathways of Tetra Pak were proposed.

Beam splitter and router via an incoherent pump-assisted electromagnetically induced blazed grating.

We propose a scheme for a beam splitter and a beam router via an electromagnetically induced blazed grating in a four-level double-Λ system driven by an intensity-modulated coupling field and an incoherent pump field. The blazed grating relies on the incoherent pump process, which helps in inducing large refractivity with suppressed absorption or even gain. Consequently, the weak probe beam can be effectively deflected with high diffraction efficiency, and, meanwhile, its energy is amplified. When using an intensity mask with two symmetric domains in the coupling field, the presented blazed grating provides the possibility of a symmetric beam splitter. The diffraction efficiency and diffraction order of the gratings are sensitive to the intensity of the coupling field, and, thus, the gratings can function as a tunable asymmetric beam splitter or a beam router, which distributes the probe field into different spatial directions. Therefore, the proposed scheme may have potential applications in optical communication and networking.

Effects of various kinetic rates of FtsZ filaments on bacterial cytokinesis.

Cell morphodynamics during bacterial cytokinesis are theoretically explored by a combination of phase field model for rod-shaped cells and a kinetic description for FtsZ ring maintenance. The division times and cell shapes have been generally decided by the competition between the constriction forces generated by FtsZ rings and the curvature elastic energy for cells. The dependences of cell morphodynamics during bacterial cytokinesis on various kinetic rates of FtsZ filaments are focused in the present study. It is found that the obtained results with the experimental parameters are well comparable to the observed results physiologically. Likewise, the quasi-steady states for FtsZ rings are found to be well consistent with the theoretical results derived from the kinetic description of FtsZ rings. In addition, morphological phase diagram is presented as functions of the membrane associate rate for both short FtsZ filaments and free FtsZ monomers, and the depolymerization rate of GDP-bound FtsZ monomers at the tip of filaments within the ring. Our results would provide a better understanding of the details of in vivo kinetics, including the kinetic rates within FtsZ rings.

A Novel Thermal Sensor for the Sensitive Measurement of Chemical Oxygen Demand.

A novel rapid methodology for determining the chemical oxygen demand (COD) based on a thermal sensor with a flow injection analysis system was proposed and experimentally validated. The ability of this sensor to detect and monitor COD was based on the degree of enthalpy increase when sodium hypochlorite reacted with the organic content in water samples. The measurement results were correlated with COD and were compared against the conventional method using potassium dichromate. The assay required only 5-7 min rather than the 2 h required for evaluation by potassium dichromate. The linear range was 5-1000 mg/L COD, and the limit of detection was very low, 0.74 mg/L COD. Moreover, this method exhibited high tolerance to chloride ions; 0.015 mol/L chloride ions had no influence on the response. Finally, the sensor was used to detect the COD of different water samples; the results were verified by the standard dichromate method.

[Prokaryotic Expression and Immunoreactivity Analysis on Profilin of Toxoplasma gondii].

OBJECTIVE: To clone and express the profilin (PRF) gene of Toxoplasma gondii, and analyze the immunoreactivity. METHODS: Total RNA was extracted from tachyzoites of T. gondii RH strain. The coding region of TgPRF was amplified with a pair of specific primers. PCR product was digested with double restriction enzyme and ligated into pET30a(+) vector. The recombinant pET30a(+)-TgPRF plasmid was transformed into E. coli DH5α with positive clones confirmed by the double restriction enzyme digestion, PCR and sequencing. The correct plasmid was transformed into E. coli BL21 and induced by IPTG. The expressed proteins were purified with Ni-NTA affinity chromatography and analyzed by SDS-PAGE. Western blotting with rabbit anti-T. gondii serum was used to analyze its antigenicity. RESULTS: The product of RT-PCR was with 492 bp. pET30a-TgPRF was confirmed by the double restriction enzyme digestion, PCR and sequencing. SDS-PAGE analysis showed that the expressed product was a soluble protein with a relative molecular weight of 35,000. Western blotting assay revealed that rTgPRF was recognized by rabbit anti-T. gondii serum. CONCLUSION: TgPRF gene has been expressed in prokaryotic expression system and shows immunoreactivity.

[Cloning, expression and immunogenicity analysis of malate dehydrogenase gene of Toxoplasma gondii].

OBJECTIVE: To clone and express the malate dehydrogenase (MDH) gene of Toxoplasma gondii, and analyze the immunogenicity. METHODS: Total RNA was extracted from tachyzoites of RH strain of T. gondii (GenBank accession No. AY650028). The coding region of TgMDH was amplified with a pair of specific primers. The product of RT-PCR was digested with double restriction enzyme and ligated into pET30a (+) vector. The recombinant pET30a (+)-TgMDH plasmid was transformed into E. coli DH5alpha. The positive clones were confirmed by the double restriction enzyme digestion, PCR and sequencing. The correct plasmid was transformed into E. coli BL21 and induced by IPTG. The expressed proteins were analyzed by SDS-PAGE. Conditions for expression were optimized. Abundant soluble rTgMDH protein was purified with Ni-NTA affinity chromatography. Mice was intranasally immunized with purified rTgMDH and murine anti-rTgMDH serum was prepared. Western blotting with murine anti-rTgMDH serum and rabbit anti-T. gondii serum was used to analyze its immunogenicity. RESULTS: The product of RT-PCR was with 951 bp. The recombinant plasmid pET30a(+)-TgMDH was confirmed by the double restriction enzyme digestion, PCR and sequencing. A soluble recombinant protein with relative molecular weight of 36 000 was analyzed by SDS-PAGE, followed by coomassie blue staining. Western blotting revealed that rTgMDH can be recognized by murine anti-rTgMDH serum and rabbit anti-T. gondii serum. CONCLUSION: TgMDH gene has been expressed in prokaryotic expression system and shows immunogenicity.

Complete uni-port video-assisted thoracoscopic surgery for surgical stabilization of rib fractures: a case report.

BACKGROUND: Rib fractures are a common injury in trauma. Potential complications include pain, pneumonia, respiratory failure, disability, and death. Surgical stabilization of rib fractures (SSRF) has become an available treatment option, and complete video-assisted thoracoscopic surgery (VATS) for SSRF is gradually accepted because of minimally invasive and pain relief. To our knowledge, complete uni-port VATS for SSRF has not yet been reported. CASE PRESENTATION: A 53-year-old man accidentally fell off a three-meter high scaffolding while working resulting in severe chest pain and shortness of breath. He was found with left 7th through 11th rib fractures with a pulmonary contusion from computed tomography (CT). A 4 cm incision was made in the 7th intercostal space in the midaxillary line, and complete uni-port VATS for SSRF were operated. The patient's pain was significantly relieved after the operation, and the scar was tiny and unapparent. CONCLUSIONS: Complete uni-port VATS for SSRF is a novel and modificatory method of operation with the benefit of minimal invasion, meanwhile, intrathoracic injuries could be treated at the same time. Further study is warranted.

DNMT1 mediates proliferation, migration and invasion of extravillous trophoblasts by regulating the methylation level of APLNR.

INTRODUCTION: Proliferation, migration and invasion of extravillous trophoblasts (EVTs) play an important role in the progression of preeclampsia (PE). The purpose of this study was to investigate the molecular mechanism by which DNA methylase regulates the transcription level of APLNR and affects the phenotypic function of EVTs. MATERIALS AND METHODS: PE mice model and H/R model in HTR8/Svneo cells were constructed. Clinical samples of normal pregnant women and PE patients were collected. Expression and methylation level of APLNR in vivo and in vitro were detected. ChIP-qPCR was used to detect the binding of DNA methyltransferase at the APLNR promoter. The expression of DNA methyltransferase 1 (DNMT1), NO and eNOS in vitro were detected. EVTs proliferation, migration and invasion in vitro were detected. RESULTS: In placental tissues or HTR8/Svneo cells of the PE model group, the expression of APLNR was reduced and APLNR methylation level was up-regulated. There was no significant difference in the APLNR expression in placental tissues between normal pregnant women and PE patients. H/R conditions only promote the binding of DNMT1 at the APLNR promoter. DNMT1 interference decreased the enrichment degree of DNMT1 in APLNR promoter region and up-regulated the mRNA and protein levels of APLNR in vivo and in vitro. The activation of APLNR by Elabela (ELA) can promote eNOS transcription, thereby promoting cell proliferation and NO level, while eNOS inhibitor can reverse this effect. DNMT1 down-regulation inhibted APLNR methylation level, promoted eNOS transcription, and promoted EVTs proliferation, migration and invasion, which could be revised by the interference of APLNR. DISCUSSION: DNMT1 promotes eNOS transcription by inhibting APLNR methylation level, and promotes EVTs proliferation, migration and invasion, thus providing a new and broad application prospect for PE treatment.

Mid-Long-Term Effect of Metabolic Surgery on Type 2 Diabetes in Nonobese Patients: a Meta-analysis.

BACKGROUND: This study aimed to perform a meta-analysis regarding the mid-long-term effect (≥ 2-year follow-up) of metabolic surgery on T2DM in non-obese patients. METHODS: PubMed, EMBASE and CENTRAL databases were searched for clinical studies from inception to March 2023. Stata 12.0 was used for data aggregation. Sensitivity, subgroup, and meta-regression analyses were performed when feasible. RESULTS: This meta-analysis included 18 articles involving 548 patients. A pooled rate of 47.5% of T2DM remission was found after metabolic surgery. To be more specific, 83.5% was obtained for hemoglobin A1c (HbA1c) < 7.0%, 45.1% for HbA1c < 6.5%, and 40.4% for HbA1c < 6.0%. Subgroup analysis showed that one-anastomosis gastric bypass (OAGB) had a higher remission rate (93.9%) than other surgeries. Studies conducted in America had a higher remission rate (61.4%) than in Asia (43.6%). Meta-regression analysis displayed that publication year, number of patients, study design, preoperative age, BMI, and quality assessment score were not significantly associated with T2DM remission rate. Additionally, metabolic surgery could result in significant reductions in BMI (-4.133 kg/m2), weight (-9.874 kg), HbA1c (-1.939%), fasting blood glucose, fasting C-peptide, and fasting insulin. However, metabolic surgery seemed to have poorer glycemic control in non-obese than obese T2DM patients. CONCLUSION: A moderate mid-long-term effect of T2DM remission was observed after metabolic surgery in non-obese patients. However, we still need more prospective multi-institutional studies using the same definitions for diabetes and the same surgical technique for the surgery. Without this, the exact role of bariatric surgery in non-obese patients is unanswered.

[Expression and significance of AT1-AA and ET1 in materal peripheral blood, umbilical cord blood and placenta in preeclampsia].

OBJECTIVE: To investigate the expression of autoantibodies to the angiotensin II type I receptor (AT1-AA) and endothelin-1 (ET-1) in pregnant women's blood and explore their correlation with the pathogenesis of preeclampsia. METHODS: Ninety pregnant women who delivered from June 2011 to December 2011 in the First Affiliated Hospital of Zhengzhou University were chosen as the study objects. They were divided into mild preeclampsia group (n = 30), severe preeclampsia group (n = 30) and normal group (control group, n = 30). The levels of AT1-AA and ET1 in maternal peripheral blood and umbilical cord blood were detected by ELISA, and the mRNA expression levels of AT1-AA and ET1 in placenta tissues were determined by reverse transcription (RT) PCR. Moreover, the correlation clinical indexes were detected and analysed. RESULTS: (1) The levels of AT1-AA and ET1 in maternal peripheral blood of preeclampsia [mild group: (114 ± 19) ng/L and (31 ± 9) ng/L, severe group: (145 ± 15) ng/L and (38 ± 10) ng/L] were both significantly higher than that of control group [(59 ± 5) ng/L, (17 ± 4) ng/L]. In addition, compared with mild group, the levels of AT1-AA and ET1 in severe group were significantly higher (P < 0.05). (2) The levels of AT1-AA and ET1 in umbilical cord blood of preeclampsia [mild group: (105 ± 14) ng/L and (35 ± 6) ng/L, severe group: (118 ± 14) ng/L and (40 ± 5) ng/L] were significantly higher than that of control group [(61 ± 12) ng/L, (24 ± 5) ng/L]. In addition, compared with mild group, the levels of AT1-AA and ET1 in severe group were significantly higher (P < 0.05). (3) The mRNA expression levels of AT1-AA and ET1 in placenta tissues of mild group (0.313 ± 0.039, 0.296 ± 0.028) and severe group (0.568 ± 0.052, 0.577 ± 0.046) were significantly higher than that in control group (0.198 ± 0.017, 0.137 ± 0.012), and the levels in severe group were significantly higher than that in mild group (P < 0.05). (4) There was an evident positive correlation between AT1-AA and ET1 levels of preeclampsia women's peripheral blood, umbilical cord blood and placenta (P < 0.05). (5) The level of AT1-AA in umbilical cord blood of preeclampsia pregnant women was positively correlated with S/D value of umbilical artery (P < 0.05), and negatively correlated with the weight of the birth and the placental (P < 0.05). CONCLUSION: The AT1-AA in the blood of pregnant women plays an important role in promoting the generation and development of preeclampsia by increasing the ET1 secretion.

iTRAQ-Based Proteome Profiling of Differentially Expressed Proteins in Insulin-Resistant Human Hepatocellular Carcinoma.

Recently, the incidences of insulin resistance (IR) and IR-related complications have increased throughout the world, which also associate with poor prognosis in hepatocellular carcinoma (HCC). Numerous studies had been focused on the role of IR in tumorigenesis and prognosis of HCC. The proteomic analysis of IR related hepatocellular carcinoma had not been reported by now. In the present study, 196 differentially expressed proteins (DEPs) were identified between insulin resistant HepG2 cells and their parental cells, of which 109 proteins were downregulated and 87 proteins were upregulated. Bioinformatics analysis indicated that these DEPs were highly enriched in process of tumorigenesis and tumor progression. PPI network analysis showed that SOX9, YAP1 and GSK3ß as the key nodes, were involved in Wnt and Hippo signaling pathways. Survival analysis revealed that high expression of SOX9 and PRKD3 were strongly associated with reduced patient survival rate. parallel reaction monitoring (PRM) and Western blot analysis were applied to verify the protein level of these four key nodes mentioned above, which showed the same trend as quantified by isobaric tags for relative and absolute quantitation (iTRAQ) and confirmed the reliability of our Proteome Profiling analysis. Our results indicated that IR related dysregulation of protein expression might participated in tumorigenesis and malignant phenotype of hepatocarcinoma cells.

Is the urinary iodine/creatinine ratio applicable to assess short term individual iodine status in Chinese adults? Comparison of iodine estimates from 24-h urine and timed-spot urine samples in different periods of the day.

BACKGROUND: Urinary iodine concentration (UIC) is routinely used to evaluate the population iodine status while the uniform method for the individual level assessment is uncertain. OBJECTIVES: To explore the 24-h urinary iodine excretion (UIE) in five different periods of the day and the corresponding prediction equations respect by the use of creatinine-corrected UIC. METHODS: We collected 24-h, spot and fasting urine in five periods of the day to estimate 24-h UIE by the six different prediction equations. We compared the estimated creatinine-corrected UIC to the collected 24-h UIE and identified the most suitable equations in each period of the day. RESULTS: Among the six different prediction equations, the equation of Kawasaki T was the best to estimate the 24-h UIE by fasting urine among Chinese adults. Among the five periods of time, the equation of Knudsen N was the best to estimate the 24-h UIE in the non-morning period. CONCLUSION: Urinary iodine status at the individual level could be estimated by different creatinine-based equations at different periods of the day.

[Protection effect of baicalin-regulated IKKα on inflammatory reaction of human oral keratinocytes].

PURPOSE: To observe the regulation of baicalin on IKKα mediated MASPIN in Human oral keratinocytes (HOKs) inflammatory reaction, this study was to explore the molecular regulation mechanism of baicalin on oral mucosal inflammation. METHODS: HOKs were stimulated by lipopolysaccharide (LPS) to mimic the inflammatory response of oral mucosal inflammation in vitro. CCK-8 assay was used to detect the toxicity of baicalin to HOKs; then different concentrations of baicalin were pre-treated to LPS-stimulated HOKs, enzyme-linked immunosorbent assays (ELISA) was used to detect the secretion of IL-6 and TNF-α in LPS-stimulated HOKs; reverse transcription polymerase chain reaction(RT-PCR) and Western blot assay were used to detect the regulatory effects of baicalin on gene and protein expression levels of IKKα mediated MASPIN in LPS-stimulated HOKs. SPSS 21.0 software package was used for statistical analysis of the data. RESULTS: HOKs stimulated by 10 µg/mL LPS successfully simulated the inflammatory environment of oral mucosal inflammation. The concentration of baicalin between 1 µg/mL and 20 µg/mL had no toxic effect on HOKs. With the increasing concentration of baicalin, the expression of MASPIN increased gradually, while the expression of IKKα and inflammatory factors decreased gradually(P＜0.05). CONCLUSIONS: Baicalin can decrease the expression of inflammatory factors in LPS-stimulated HOKs, down-regulate IKKα and up-regulate MASPIN.

A sensitive method for simultaneous determination of four macrolides by CE with electrochemiluminescence detection and its applications in human urine and tablets.

A sensitive method for simultaneous determination of azithromycin (AZI), acetylspiramycin (ACE), erythromycin (ERY), and josamycin (JOS) was developed by CE coupled with electrochemiluminescence detection with Ru(bpy)(3) (2+). The parameters related to separation and detection were investigated in detail. The four macrolides were well separated and detected within 6 min under the optimized conditions. The LOD (S/N=3) of AZI, ACE, ERY, and JOS were 1.2 x 10(-9), 7.1 x 10(-9), 3.9 x 10(-8) and 9.5 x 10(-8) mol/L, respectively. The LOQ (S/N=10) of AZI, ACE, ERY, and JOS in human urine were 8.2 x 10(-8), 2.5 x 10(-7), 8.9 x 10(-7) and 1.2 x 10(-6) mol/L, respectively. The recoveries of the four macrolides in human urine and pharmaceutical tablet samples were 85.0-104.0% at different concentration levels.

Sensitive determination of tilmicosin, erythromycin ethylsuccinate and clindamycin by CE with electrochemiluminescence detection using azithromycin as internal standard and its applications.

A sensitive approach for the simultaneous determination of tilmicosin, erythromycin ethylsuccinate and clindamycin was developed by CE coupled with electrochemiluminescence detection with ionic liquid. The parameters for CE, electrochemiluminescence detection and the effect of ionic liquid were investigated systematically. The three analytes were well separated and detected within 8 min. The limits of detection (S/N=3) of tilmicosin, erythromycin ethylsuccinate and clindamycin are 3.4x10(-9), 2.3x10(-8) and 1.3x10(-8) mol/L, respectively. The precisions (RSD%) of the peak area and the migration time are from 0.8 to 1.5% and from 0.2 to 0.5% within a day and from 1.8 to 2.7% and from 0.6 to 0.8% in 3 days, respectively. The limits of quantitation (S/N=10) of tilmicosin, erythromycin ethylsuccinate and clindamycin are 3.2x10(-8), 2.9x10(-7) and 9.1x10(-8) mol/L in human urines and 5.5x10(-8), 3.2x10(-7) and 2.1x10(-7) mol/L in milk samples, respectively. The recoveries of three analytes at different concentration levels in urine, milk and drugs are between 90.0 and 104.7%. The proposed method was successfully applied to the determination of three analytes in human urine, milk and drugs.