Objective To establish a HPLC-MS/MS method to deter-minate the concentration of sitagliptin in human plasma .Methods The samples were treated by protein precipitation method .The chromato-graphic column was Venusil ASB C 18(2.1 mm ×50.0 mm,3.0 μm), mobile phase was 100% water contained with 0.1% formic acid -100%acetonitrile contained with 0.1%formic acid, flow rate was 0.40 mL· min-1, column temperature was 50 ℃, injection volume was 20.0 μL, mobile phase.The specificity, standard curve and lower limit of quantitation, precision and recovery , matrix effect and stability of the method were investigated.Results The standard curve of metformin was y=4.73×10 -3x+7.32×10 -4( r=0.998 8 ), and sitagliptin had good linear relationship in 1.00 -800.00 ng· mL-1.The limit of quantifica-tion was 1.00 ng· mL-1.The intra-day RSD and inter-day RSD were less than 12.0%, respectively.The recovery rate of extraction was over 95.9%.Conclusion The method is simple, rapid, accurate and sensi-tive, which is suitable for the determination of sitagliptin in human plasma.

Objectives: To evaluate the changes of left atrial volume (LAV) and the maximum ostial cross-sectional area (CAS) of pulmonary vein (PV) in atrial fibrillation (AF) patients after circumferential pulmonary vein isolation radiofrequency catheter ablation (CPVA-RFCA) and to explore their relationship to AF recurrence by enhanced cardiac MRI evaluation. Methods: Our research included in 2 groups: Control group, n=20 healthy subjects and AF group, n=78 patients whom were classified into 2 subgroups as Paroxysmal AF subgroup, n=46 and Persistent AF subgroup, n=32; 66 patients received CPVA-RFCA and based on 6 months post-operative recurrence, they were divided into another set of 2 groups: AF recurrent subgroup, n=17 and Non-AF recurrent subgroup, n=49. Pre- and 6 months post-operative maximum ostial CSA of PV were measured by enhanced cardiac MRI, LAV were obtained by 3D reconstruction and the differences were compared between AF group and Control group, Paroxysmal AF subgroup and Persistent AF subgroup, AF recurrent subgroup and Non-AF recurrent subgroup; their relationships to AF recurrence were studied.Results: Compared with Control group, AF group had increased LAV and elevated ostial CSA of superior PV (SPV), both P<0.05. Compared with Paroxysmal AF subgroup, Persistent AF subgroup had increased LAV and elevated ostial CSA of SPV, both P<0.05. Compared with pre-operative condition, at 6 months after the operation, Non-AF recurrent subgroup showed reduced ostial CSAs in left SPV (LSPV), right SPV (RSPV), right inferior PV (RIPV) and decreased LAV, all P<0.05;while AF recurrent subgroup showed expanded RSPV and increased LAV,allP<0.05.Post-operative reductions of LAV and ostial CSA of SPV had close correlation; multivariate Logistic regression analysis indicated that LAV (HR=1.05, P<0.01)and ostial CSA of RSPV(HR=1.09,P=0.05)were related to AF recurrence after RFCA. Conclusions: CAPV-RFCA could reverse left atrial and PV remodeling in AF patients, LAV and ostial CSA of RSPV were related to post-operative AF recurrence.

OBJECTIVE: To explore the effect of bone morphogenetic protein 4(BMP4) on the cell cycle and apoptosis of hemaropoictic stem and progenitor cells (HSPC) in conditions of 5-fluorouracil (5-FU)-inducing bone marrow suppression and stress hemogenesis, and its possible mechanism. METHODS: The C57BL transgenic mice with BMP4 overexpression were established and were enrolled in transgenic group (BMP4 group), at the same time the wild type mice matching in age, sex and body weight were selected and were enrolled in control group (WT group). The bone marrow suppression was induced by injection with 5-FU in dose of 150 mg/kg, then the nucleated cells were isolated from bone marrow. After the HSPCs were markered with C-kit/sca-1 fluorescent antibodies, the changes of cell cycle and apoptosis of HSPC were detected by Aunexin V/PI and Ki67/DAPI double staining; the cell cycle-essociated hemotopoietic regulatory factors were detected by RT-qPCR. RESULTS: Under physiologic status, there were no significant differences in cell cycle and apoptotic rate of HSPC between WT group and BMP-4 group. After the bone marrow was suppressed, the ratio of HSPC at G0 phase in BMP4 group significantly decreased(P＜0.05); the apoptosis rate of HSPC significantly increased(P＜0.05); the mRNA expression levels of hypoxia-inducing factor Hif-1α and chemotactic factor CXCL12 in stroma of BMP4 group were down-regulated significanfly(P＜0.05). CONCLUSION Under non-physiologic conditions such as stress hemogenesis or bone marrow suppression, the up-regulation of BMP4 can promote HSPC into cell cycle and apoptosis of HSPC, moreover, the BMP4 may play a regulatory role for cell cycle of HSPC through direct or indirect down-regulation of Hif-1α and CXCL-12 expressions.
Animals ; Antineoplastic Agents ; Apoptosis ; Bone Morphogenetic Protein 4 ; Cell Cycle ; Hematopoietic Stem Cells ; Mice ; Mice, Inbred C57BL