There is still a certain recurrence rate after extensive lymphadenectomy even to patients with node-negative gastric cancer.It promotes the researchers to use a more sensitive and effective way to track tumor cells which are missed,especially lymph node micrometastases.With the development of detection tech-nology,the diagnostic rate of micrometastasis is significantly increased.There are so many controversies about the impact of lymph node micrometastases that no consensus on the clinical treatment can be reached.In recent years,with the rise of endoscopic therapy,how to balance the relationship between the quality of life and the safety makes the research of micrometastases more urgent.

Objective To construct the mouse CD40 RNA interfering(RNAi) lentiviral vector and prepare dendritic cells (DCs) with low expression of CD40. And to explore the mechanism of inducing T lymphocyte incompetence by blocking CD40/CD40L costimulatory pathway. Methods Mouse myeloid DCs were cultured in selective medium containing necessary cytokines for DC growth in vitro. CD40 RNAi gene was transfected into DCs with lentiviral vector. The expression levels of CD40 mRNA and protein were assayed by real-time quantitative PCR and flow cytometry respectively. The influences on DCs stimulating the proliferation ability of T lymphocyte were observed through mixed lymphocyte culture(MLC). Results Myeloid DCs have been harvested from mouse through cell culture in vitro. A mouse CD40 RNAi ientiviral vector was built successfully. The lentiviral titer was 8×10~9 TU/ml. The CD40 mRNA inhibition rate after infection was significantly higher(P<0.05). The CD40 protein expression of DCs was significandy lower(P<0.05). The result of MLC demonstrated that the index of stimulation to T lymphocyte of CD40 RNAi transfected DC significantly decreased compared with non-transfected DC and empty plasmid transfected DC(P< 0.01). Conclusion Large quantity of myeloid DCs with typical histological configuration are obtained through in vitro culture in selective medium which may activate naive T lymphocyte to generate immune response. While DCs were infected by CD40 RNAi lentiviral vector, CD40 protein expression was inhibited significantly. The DCs could hamper the activation of allogeneic T lymphocyte by blocking CD40/CD40L cestimulatory pathway and induce T cell allergy. This will make the good foundation for studying the immune tolerance of CD40 RNAi.

Objective To investigate the effect of blocking CD40/CD40L costimulatory pathway by the lentiviral vector-mediated RNA interference on the survival of mouse cardiac allograft. Methods Mouse bone marrow-derived dendritic cells (DCs) were infected by CD40-RNAi lentiviral vector in vitro, and tolerogenic DCs (Tol-DCs) with decreased CD40 expression were prepared. Fluorescence real-time quantitative PCR and flow cytometry were used to analyze the expression of CD40 mRNA and DC surface antigens CD40, CD11c, MHC Ⅱ before and after infection. Mouse model of heterotropic abdominal heart transplantation was established. Seven days prior to heart transplantation, Tol-DCs with decreased CD40 expression were transfused into recipient mice intravenously (lentivirus infected DC group). Control group and non-infected DC group were assigned simultaneously. The survival of cardiac allograft was monitored and pathological grade of acute rejection 7 days after heterotropic abdominal heart transplantation was determined. Results The transcription of CD40 mRNA of DCs was down-regulated significantly at 48 h after CD40-RNAi lentiviral vector infection, and the inhibition rate was 80. 9%. The expression of CD40 protein was also significantly decreased as compared with control group (40. 07% ± 4. 03% ) ( P ＜ 0. 05 ).Compared to control group (8 ± 2 days) and non-infected DC group (9 ± 1 days), the survival time of cardiac allograft in CD40-RNAi lentivirus infected DC group (14 ± 4 days) was significantly prolonged (P＜ 0. 05 ), and the pathological grade of acute rejection decreased significantly ( P ＜ 0. 05 ).Conclusion Blocking CD40/CD40L costimulatory pathway could hamper the activation of allogeneic T lymphocyte, inhibit the acute rejection and prolong the survival of mouse cardiac allograft.

Objective To investigate the changes of epithelial sodium channel(ENaC) expression and sodium and water transport function in the neonatal rat pulmonary edema induced by hyperoxia.Methods The neonatal rats were randomly divided into the hyperoxia group and the control group.After 1,3,5 and 7 d hyperoxia exposure,the lung tissues were collected to measure the wet-to-dry weight ratio and the expression of α-,β-and γ-ENaC subunits were detected by western blot analysis.Alveolar fluid clearance (AFC) and amiloride-sensitive AFC were measured after 5 d to reveal the effect of hyperoxia on the activity of ENaC.Results The lung water contents significantly increased in the hyperoxia group indicating that pulmonary edemahappened(3 d:(6.37 ±0.64) vs (5.56±0.15),t=3.46,P＜0.01;5 d:(5.86 +0.52) vs (5.11±0.21),t=-3.82,P ＜0.01;7 d:(5.56±0.45) vs (4.80±0.09),t =-4.72,P ＜0.01).AFC increased significantly,but no significant difference was found in amiloride-insensitive AFC between the two groups which indicate that amiloride-sensitive AFC increased significantly (AFC:(20.32 ± 3.33) ％ vs (12.97 ± 2.46) ％,t =-6.16,P ＜ 0.01 ; amiloride-insensitive AFC:(10.42 ± 3.44) ％ vs (8.67 ± 3.13) ％,t =-1.30 P =0.21).The expression of α-,β-and γ-ENaC did not reduced after hyperoxia exposure compared with the control group.Conclusion Although bronchopulmonary dysplasia of early pulmonary edema induced by hyperoxia,dysfunctional transport of Na + may not be a key factor involved in pulmonary edema at the early stage of bronchopulmonary dysplasia.

Objective To evaluate the variation of functional urethra length on urine control,explore a new method to prevent urinary incontinence and seek urodynamic evidence after radical prostatectomy. Methods Sixteen male dogs,matched in body weight,were randomly divided into two groups. Group A were used to test the different rest urethral pressure profile after resection of prostate,resection of distant prostate plus posterior urethra in length of 1.5 cm and 2.0 cm respectively; Group B to test the different rest urethral pressure profile on pedicle myotube in length of 2.0 cm and 1.0 cm using anterior bladder flap respectively after resection of prostate and posterior urethra in length of 2.0 cm. Results The urodynamic indexes fell off while the functional urethra length decurtated gradually in group A,but they went up in group B. The two groups showed significant difference before and after the resection of prostate and distant urethra in length of 2. 0 cm. Conclusion There was a direct ratio between the functional urethra length and the capability of urethral urine control. Reconstruction of functional urethra using anterior bladder flap pedicle myotube is a good choice to treat urinary incontinence after radical prostatectomy.

Objective:To evaluate the biological functions and underlying mechanisms of transcription factor PAX5 in promoting cell proliferation and anti-apoptosis in multiple myeloma cells.Methods:a PAX5 knockdown cell line was established by stable transfection of vector-based PAX5-siRNA into multiple myeloma IM9 cells.The expressing level of PAX5,p53,XBP-1 and c-Myc was examined by either or both Western blot and RT-PCR for the targets.Cell proliferation and apoptosis were assayed by MTT and flow cytometry,respectively.Results:PAX5 was expressed selectively in IM9 cells,but neither in another common used multiple myeloma KAS6 cells nor in the prostate cancer cells DU145 and PC3.Knockdown PAX5 led to a significant up-regulation of p53 and XBP1,but decreased c-Myc expressions in IM9 cells that were correlated with the increased sensitivity of drug-induced apoptosis and decreased proliferation rates when compared to the control cells.Conclusion:PAX5 is specifically expressed in IM9 cells,which promotes cell proliferation and anti drug-induced apoptosis.In addition to inhibiting the expression of p53 and XBP-1,PAX5 is found to induce expression of oncogene c-Myc in IM9 cells,and this finding indicates an undiscovered signal pathway that may contributes to the malignancy of Multiple Myeloma cells.

Objective To investigate the effect of hyperoxia on fluid transport by fetal distal lung epithelia(FDLE) and the expression of epithelial sodium channel(ENaC) in these cells.Methods FDLE were isolated and randomized into hyperoxia group and normoxia group,which were primarily cultured under hyperoxic or normoxic conditions,respectively.Fluid transport was measured using monolayers of FDLE cultured on Transwell permeable inserts.Western blot was applied to examine the α-ENaC expression.Results Fluid transport across monolayer of FDLE was increased in cells exposed to hyperoxia compaired with cells cultured in normoxic conditions (1.78 ± 0.19 vs 1.06 ± 0.11,P ＜ 0.001).Amiloride significantly decreased the fluid transport in both of the hyperoxia and normoxia groups,but in the presence of amiloride there were no difference between the two groups.The expression of α-ENaC was inhibited by hyperoxia to some extent(24h:0.44 ±0.04 vs 0.40 ±0.04,P=0.22; 48h:0.35 ±0.03 vs 0.47 ±0.06,P =0.03).Conclusion Hyperoxia enhanced total and amiloride-sensitive fluid transport by FDLE.However,the expression of α-ENaC decreased in these cells.

Objective To establish the mouse bone marrow-derived dendritic cells expressing FasL protein and explore the mechanism of inducing allogeneic mouse spleen T lymphocyte apoptosis. MethodsMouse myeloid DCs were cultured in selective medium zontaining essential cytokines for DC growth in vitro. The mouse DCs were transfected with liposome-mediated FasL gene. The levels of FasL mRNA before and after transfection were assayed by real-time quantitative PCR. The expression levels of FasL protein were assayed by flow cytometry(FCM)and Western blot. Non-transfected DC，empty plasmid transfected DC and FasL transfected DC were infused intravenouslY into allogeneic mouse. After 7 days, the apoptosis in spleen T lymphocytes was evaluated by TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP nick-end-labeling)method and FCM. ResultsCultured in vitro, the mature myeloid DCs from mouse could be obtained.The expressions of FasL mRNA and protein in FasL transfected DCs were significantly higher. Through the detection of spleen T lymphocyte apoptosis with TUNEL，the apoptosis index(AI)was higher in FasL transfected DC(11.67±1.53)，compared with non-transfected DC(2.67±0.58)and empty plasmid transfected DC(3.33±0.58)，P＜0.01. ConclusionA large quantity of myeloid DCs can be obtained through in vitro culture in selective medium. The liposome-mediated FasL gene transfected DCs could successfully express high levels of FasL protein. Intravenous infusion of FasL gene transfected DCs could induce apoptosis of allogeneic mouse spleen T lymphocytes.

Objective To explore the effects of CD4+CD25+Treg cell on the allograft after infusion of dendritic cells (DCs) with low expression of CD40 from donor in mouse heart transplantation.Methods In vitro,mouse bone marrow-derived DCs were infected by CD40-RNAi lentiviral vector,and tolerogenic DCs (Tol-DCs) with low expression of CD40 were prepared.A heterotopic abdominal heart transplantation model was established in mice,and the other three groups that were control group,noninfected DC group and lentivirus infected DC group were designed correspondingly.Cardiac allograft survival time was recorded and pathological grading for acute rejection was assessed on the 7 d after heterotopic abdominal heart transplantation.Concentrations of CD4+CD25+Treg cells in peripheral blood were analyzed before and after transplantation by flow cytometry.Results After 48 h infection of DCs by CD40-RNAi lentiviral vector in vitro,the expression of CD40 mRNA was down-regulated significantly,whose inhibition rate was 80.9％.The expression of CD40 was decreased from 74.37％ ±4.08％ to 40.07％ ± 4.03％ (P＜0.05) after 48 h infection.Compared with the control group and the noninfected DC group,the cardiac allograft survival time was significantly prolonged in the CD40-RNAi lentivirus infected DC group,which was (14 ± 4) d(P＜0.01) ; concentrations of CD4+CD25+Treg cells in peripheral blood were increased both on the 3 d and the 7 d after transplantation (P＜0.05) ; the pathological grading for acute rejection was decreased on the 7 d after transplantation (P＜0.05).Conclusion The CD4+CD25+Treg cell in peripheral blood was protective to cardiac allograft in prolonging its survival time in mouse heart transplantation.

Objective To investigate the effect of hyperoxia on the expression and transport function of epithelial sodium channel (ENaC) in neonatal rat alveolar epithelial type Ⅱ(AT Ⅱ) cells.Methods AT Ⅱ cells were isolated from neonatal rats,and primarily cultured under hyperoxic or normoxic conditions.Western blot was applied to examine the ENaC expression,and the amiloride-sensitive Na + currents were recorded using the whole-cell patch clamp technique.Results Hyperoxia upregulate the expression of β-ENaC and γ-ENaC subunits in the neonatal rat ATⅡ cells(β-ENaC:1 d:0.43 ±0.06 vs0.32 ±0.04,P =0.047;2 d:0.73±0.06 vs 0.50±0.08,P =0.019;3 d:0.72 ±0.08 vs 0.52 ±0.06,P =0.027;γ-ENaC:1 d:0.64±0.05 vs0.53 ±0.05,P =0.044;2 d:0.76 ±0.03 vs 0.52 ±0.04,P =0.001 ;3 d:0.77 ±0.06 vs 0.61 ±0.05,P =0.025).In addition,the amiloride-sensitive Na+ currents in hyperoxia-exposed AT Ⅱ cells were also increased (1d:13.71 ±2.77 vs8.92±1.38,P＜0.001;2d:29.12±11.03 vs 10.41 ±1.80,P＜0.001),which was consistent with the upregulated expression of β-ENaC and γ-ENaC.However,the expression of α-ENaC was inhibited by hyperoxia to some extent (1 d:0.31 ± 0.05 vs 0.46 ± 0.05,P =0.025 ; 2 d:0.30 ±0.01 vs0.38±0.02,P=0.002;3d:0.37±0.06 vs 0.37 ± 0.08,P =0.983).Conclusion Hyperoxia enhanced the transport function of ENaC in neonatal rat AT Ⅱ cells.Dysfunctional transport of Na + may not be a key factor involving in pulmonary edema at the early stage of bronchopulmonary dysplasia.