Objective To study the role of IL-2 in regulating allograft rejection mediated by alloantigen-specific CD8~+ T cell.Methods T cell proliferation in vivo at a single cell level was examined using the CFSE dilution assay. IL-2 expression by activated CD4~+ versus CD8~+ T cells was determined by intracellular cytokine staining. The ability of alloantigen-specific CD8~+T cells in mediating allograft rejection was studied using the islet transplantation model.Results CD8~+ T cells divided vigorously in vivo in the allogeneic hosts regardless the presence or absence of CD4~+ T cells. CD4~+ T cells, but not CD8~+ T cells, were the primary source of IL-2 when both subsets were present. However, CD8~+ T cells could express high levels of IL-2 in the complete absence of CD4~+ T cells. In 2C TCR transgenic (Tg) mice in which the 2C TCR transgene was selectively expressed on the CD8~+ T cells that specifically recognized alloantigen (Ld) of Balb/c origin, islet allografts from Balb/c mice was promptly rejected by the 2CTg recipients with mean survival time of only 8 days. In contrast, in 2CTg mice with a genetic deletion of the IL-2 gene (2CTg-IL-2KO mice), the alloantigen specific CD8~+ T cells failed to mediate the islet allograft rejection and all the Balb/c islets survived for more than 50 days.Conclusions CD8~+ T cells appear to be very plastic in producing and utilizing IL-2. In the presence or absence of CD4~+ T cells, CD8~+ T cells can use CD4~+ derived or self derived IL-2 for proliferation and effector function respectively. In an alloantigen specific TCR transgenic model, the effector function of CD8~+ T cells is strictly IL-2 dependent. Thus, in situations where graft rejection is mediated solely by the CD8~+T cells, blocking IL-2/IL-2R pathway may be critically important in preventing transplant rejection.

Objective To evaluate the accuracy and feasibility of 64-slice spiral CT (64SCT) in assessing coronary artery disease.Methods A total of 30 suspected patients (male 21 cases, female 9 cases, and mean age of 54.6 years) were undergone both 64SCT and selective coronary angiography (SCA). Volume redering (VR) ,multiplanar reconstruction (MPR), maximum intensity projection (MIP) and transverse section were reconstructed. The results of coronary reconstructions were compared with SCA to analyze the accuracy of the 64SCT in detecting coronary artery stenoses.Results In the 396 segments of coronary artery(diameter≥2 mm)of 30 patients, 385 were judged to be evaluable by 64SCT. The evaluable rate was 97.2%. The sensitivity, specificity, positive predictive value and negative predictive value of the 64SCT in detecting coronary artery stenoses(≥50% of stenosis) were 96.22%, 94.56%, 89.44% and 96.88%. The accuracy rate of 64SCT in detecting ≥50% stenosis of coronary artery was 95.90%.Conclusion 64SCT has high accuracy in detecting coronary artery stenoses, as a noninvasive method,it can be used for screening patients with known or coronary artery diseases.

Objective To investigate the role of OX40 in the mechanisms of memory T cells in islet transplant tolerance.Methods The expression of OX40 on native, like memory and memory CD8+T cells was detected by RT-PCR. Splenic T cells from B6 mice were injected into Rag-/- mice via the tail vein, and the Rag-/- mice were divided into three groups (n=8 each): control group, given IgG; treatment group, given anti-OX40L; and OX40 knock-out group, given T cells from OX40 knock-out B6 mice spleen. All recipients were induced into diabetes mellitus model after adoptive transfer. Islet transplantation was performed on all Rag-/- mice as recipients. The mean survival time of islet was observed.Results The expression of OX40 in native T cells, like memory T cells and memory T cells was 2.87, 111.24 and 146.15 respectively. The expression of OX40 in like memory and memory T cells was higher than in native T cells (P<0.05). Comparison with control group , The mean survival time of the DBA/2 islet allografts in treatment group (130 days) and OX40 knock-out group (125 days) was significantly longer than in control group (21 days, P<0.05).Conclusion The OX40 expression is high in memory T cells. The mean survival time of the islet allografts can be prolonged by blocking OX40/OX40L pathway. OX40/OX40L pathway may be the key point of transplant tolerance.

Objective To investigate the effects of blockade of OX40/OX40L costimulation pathway on mice islet allograft tolerance in CD40/CD154 costimulation pathway blockade mice.Methods C57BL/6 mice were induced into diabetes mellitus as recipients,and were transplanted with DBA/2 mice islets.The recipients were divided into four groups,(1) treated with IgG as controls,(2) anti-OX40L mAb,(3) anti-CD154,(4) combined treatment of anti-OX40L mAb and anti CD154mAb.The mean survival time (MST) of islet allograft was observed.The expression of OX40 in activated T cells of CD154 deficient mice was detected.Effector T cells were obtained from the spleen of CD154 deficient mice cultured with or without anti-OX40L mAb for 3 days.The proliferation of T cells was assayed.Results The MST in the control group,anti-OX40L mAb group,anti-CD154 mAb group and anti OX40L mAb + anti-CD154 mAb group was 19,22,48,and ＞150 days respectively (P ＜0.05).The OX40 expression was readily induced in the 66％ activated T effector cells.CD154 deficient T effector cells proliferation was inhibited by the addition of anti-OX40L mAb in the culture in a dose-dependent fashion.Conclusion The blockade of OX40/OX40L costimulation pathway can promote islet allograft tolerance in CD40/CD154 costimulation pathway blockade mice by inhibiting the proliferation of T cells.

Objective To evaluate the robustness of body mass index (BMI) adapted tube current selection method for obtaining consistent image quality in MSCT coronary artery imaging Methods Initially one hundred patients in the control group ( C group) underwent cardiac scans using GE 64-row VCT with standard scan protocol (640 mA, 120 kV, 0.35 see, body bewtie, C2 filter). Noise measurement was obtained for each patient using the average of three consecutive slices in the ascending aorta with ROI of 10 mm×10 mm to establish the relationship between BMI, desired image noise (IN) and required mA. An excel table was established to predict the required mA to achieve a desired IN for each patient with different BMI. A second group of one hundred cardiac patients (L group) was scanned with BMI-aclapted mA from the table to evaluate the practicability of this method. BMI, IN, CT dose index(CTDI),effective dose (ED) were all recorded. Results For the control group of 100 patients, the mean values and standard deviations of image quality score (IQS), BMI, IN and ED were 3.71±0.54, 25.08±2.63, 24.56±5.03 and (17.63±1.68 ) mSv (with range of 15-22 msy). Regression analysis indicated linear relationship between BMI and image noise with fixed mA. Using the relationship between tube current and image noise and noise ratio between large bowtie and cardiac bowtie, the following equation for the required tube current Xma to achieve present image noise of Ins for patient with certain BMI value when using cardiac bowtie could be then obtained: Xma = Fma×( k1 x BMI + c1 )/Ina]2, where Fma = 640 mA, k1 = 1. 033, c1 = - 3.2, Ins = 27 in the study. (2) For the patients in L group, the mean values and standard deviations of IQS, BMI, and IN were 3.69±0.53, 25.07±2.91, and 26.61±3.44, respectively. The average tube current used was (469.95±113.45) mA, depending on patient's BMI values. The average effectively dose was(9.08±2.25) mSv. There was no statistically difference between the two groups in image quality( F= 0.068,P=0.794). Conclusions In 64-MSCT cardiac imaging, the use of BMI dependent tube current selection method, in conjunction with dose reduction techniques, can provide individualized scan protocol to obtain consistent image quality across patient population and to optimize dose delivery to patients.

Objective To evaluate and compare spiral CT and positron emission tomography-CT (PET-CT) in characterization of of axillary lymph nodes in breast cancer patients.Methods Forty patients with pathologically proven breast Cancer underwent contrast-enhanced spiral CT of tbe breast and axilla,13 of them also underwent PET-CT examination.One hundred and fifty-eight axillary lymph nodes were found in the 40 patients through contrast enhanced spiral CT,while 57 lymph nodes were found in the 13 patients through PET-CT.Three radiologists rated the lymph nodes found in CT images on a five-point scale.If the score was equal to or greater than 3,it was defined as positive (metastatic),otherwise negative.Visual observation and semiquantitative analysis were used to classify lymph nodes in PET-CT images.The results of spiral CT observation and PET-CT observation of lymph nodes were compared with pathological results.The relative value of CT and PET-CT was analyzed.Exact probability statistics were employed.Results One hundred and fifty eight lymph nodes of 40 patients were detected by spiral CT,91 of them were diagnosed as positive and 67 as negative Among the lymph nodes found in spiral CT,99 were positive and 59 were negative pathologicall.A total of 57 lymph nodes were found by PET-CT.Thirty-nine of them were defined as positive and 18 as negative.Among the lymph nodes found in PET-CT,39 were positive and 18 were negative pathologically.The sensitivity,specificity,accuracy,positive and negative predictive values in CT prediction in axillary lymph nodes metastases were 88.89%,94.91%,91.14%,96.70%,and 83.58%,respectively.The sensitivity,specificity,accuracy,positive and negative predictive values in PET-CT prediction in axillary lymph nodes metastases were 97.44%,94.44%,96.49%,97.44%,and 94.44%,respectively.PET-CT had no significant difference with spiral CT in sensitivity,accuracy,positive and negative predictive values for detection of axillary lymph nodes in breast cancer.But there was significant difierence between PET-CT and CT in negative predictive value(P＜0.05).Conclusions Both helical CT and PET-CT were the efficient methods in predicting the axillary lymph node status in breast cancer patiens.The negative predictive value of PET-CT was higher than that of helical CT.PET-CT has a better predictive ability than CT for the presurgical evaluation for breast cancer patients.

Objective:To investigate the mechanism of lncRNA Sox2OT in patients with Alzheimer's disease (AD) induced by A type of β peptide (Aβ1-42).Methods:Rat pheochromocytoma cells (PC12 cells) were selected and treated by Aβ1-42 to establish PC12 cell model.PC12 cells were set as blank group before induction to verify the successful construction of the cell model.The induced PC12 cells were divided into control group, Sox2OT overexpression (p-Sox2OT) group, p-Sox2OT empty vector (p-NC) group, inhibited Sox2OT expression (si-Sox2OT) group and si-Sox2OT empty vector (si-NC) group.The proliferation activity of thiazole blue (MTT) was detected.Flow cytometry was used to detect the cell cycle and apoptosis rate after transfection.Results:MTT results showed that compared with the blank group (99.67±10.50), the cell proliferation rate of the control group (29.33±5.51) was significantly reduced ( t=10.27, P<0.05). RT-qPCR results showed that compared with the control group (0.52±0.06), the Sox2OT mRNA expression level in the p-Sox2OT group (2.19±0.16) was significantly increased ( t=16.93, P<0.05). The mRNA expression level of Sox2OT in the si-Sox2OT group (0.22±0.02) decreased significantly ( t=15.28, P<0.05). Compared with the p-NC group (0.53±0.12), The mRNA expression level of Sox2OT in the p-Sox2OT group (2.19±0.16) was significantly increased ( t=16.25, P<0.05). Compared with the si-NC group (0.51±0.09), the mRNA expression level of Sox2OT in the si-Sox2OT group (0.22±0.02) was significantly decreased ( t=16.93, P<0.05). The difference between the control group, the p-NC group and the si-NC group was not statistically significant ( P>0.05). In addition, the cell proliferation ability of the p-Sox2OT group (145.00±5.12) was significantly higher than that of the si-Sox2OT group (23.33±4.93), control group (55.00±5.00), si-NC group (57.33±8.51) and p-NC group (56.00±5.57) ( t=29.65, 21.78, 27.55, 21.35, all P<0.05). The difference in cell proliferation rate between Control group, p-NC group and si-NC group was not statistically significant ( P>0.05). Cell cycle detection experiments showed that the number of cells in the G1 phase of the p-Sox2OT group was significantly lower than that of the control group and p-NC ( t=9.80, 8.57; both P<0.05), while the number of cells in the G2 phase of the p-Sox2OT group was significantly higher than that of the control group and the p-NC group ( t=11.02, 10.25; both P<0.05). The number of cells in the G1 phase of the si-Sox2OT group was significantly higher than that of the control group and the si-NC group ( t=8.22, 3.11, both P<0.05), while the number of cells in the G2 phase of the si-Sox2OT group decreased significantly, compared with the control group and the si-NC group ( t=6.32, 5.33; all P<0.05). There was no statistically significant difference in cell cycle between the control group, the p-NC group and the si-NC group (both P>0.05). In the S phase, the difference between the p-Sox2OT group and the control group was statistically significant ( t=1.84, P<0.05). The number of cells in the G2 phase of the p-Sox2OT group (19.00±1.00) was significantly higher than that of the si-Sox2OT group (3.33±1.53), the control group (10.00±1.00), si-NC group (8.55±0.73) and p-NC group (7.67±1.53) ( t=14.85, 11.02, 10.23, 10.74, all P<0.05). The apoptosis rate of p-Sox2OT group ((3.66±0.26)%) was lower than that of si-Sox2OT group ((14.25±0.80)%), control group ((8.46±0.44)%), si-NC group ((8.78±0.44)%) and p-NC group ((8.40± 0.21)%) ( t=21.81, 16.27, 20.32, 21.35, all P<0.05). For the apoptosis rate, there was no statistically significant difference between control group, p-NC group and si-NC group( P>0.05). In addition, the expression levels of p-PI3K and p-Akt in the p-Sox2OT group were significantly higher than those in the p-NC group ( P<0.05). Compared with the si-NC group, the expression of p-PI3K and p-Akt in PC12 cells in the si-Sox2OT group was significantly decreased ( P<0.05). Conclusion:lncRNA Sox2OT can promote the proliferation of PC12 cells induced by Aβ1-42 and inhibit apoptosis by regulating the PI3K/Akt pathway.