扫描电子显微镜(scanning electron microscope,SEM)是表征高分子材料微观结构及其组成信息重要的手段之一,具有操作简便、信号电子种类多样且对样品损伤较小等特点.本文系统阐述了SEM的工作原理,通过与透射电子显微镜(transmission ele...扫描电子显微镜(scanning electron microscope,SEM)是表征高分子材料微观结构及其组成信息重要的手段之一,具有操作简便、信号电子种类多样且对样品损伤较小等特点.本文系统阐述了SEM的工作原理,通过与透射电子显微镜(transmission electron microscope,TEM)进行比较,突出了其优势与特色.详细讨论了该技术的测试方法,包括样品制备、仪器参数设定、操作技巧与图像处理,并揭示了获得高质量SEM图像的关键技术.介绍了SEM不同的信号电子成像、SEM与其他仪器联用及SEM原位分析技术在高分子材料表征中的应用与进展.最后,对SEM的发展趋势进行了展望.展开更多
仿生偏振导航是近年来兴起的一种新原理导航方式,对天空光进行成像可以获得更为丰富的天空散射光的偏振信息以及分布特征,有利于提高偏振导航传感器的精度和抗干扰能力。根据现有的Stokes参量测量偏振光的原理以及成像装置的噪声模型,...仿生偏振导航是近年来兴起的一种新原理导航方式,对天空光进行成像可以获得更为丰富的天空散射光的偏振信息以及分布特征,有利于提高偏振导航传感器的精度和抗干扰能力。根据现有的Stokes参量测量偏振光的原理以及成像装置的噪声模型,对基于Stokes参量法的偏振角度测量噪声进行了建模,并根据模型进行了仿真分析。仿真结果表明:提高相机的信噪比(SNR)能够显著提高偏振成像的质量,当相机的SNR大于44 d B时,天空偏振角度的测量标准差将优于1°/像素;得到了0°,60°,120°和0°,45°,90°检偏器分布模式下对不同偏振角度的入射光测量噪声的统计分布特征。尽管0°,60°,120°的检偏器布置方案相对于0°,45°,90°的检偏器布置方案有着更大的计算复杂度,但在使用相同信噪比相机的情况下,该布置方案的噪声更小。该结论将对天空偏振光成像装置的构建及其误差分析与补偿技术提供参考。展开更多
AIM: To compare effects of different resuscitation fluid on microcirculation, inflammation, intestinal barrier and clinical results in severe acute pancreatitis (SAP). METHODS: One hundred and twenty patients with SAP...AIM: To compare effects of different resuscitation fluid on microcirculation, inflammation, intestinal barrier and clinical results in severe acute pancreatitis (SAP). METHODS: One hundred and twenty patients with SAP were enrolled at the Pancreatic Disease Institute between January 2007 and March 2010. The patients were randomly treated with normal saline (NS group), combination of normal saline and hydroxyethyl starch (HES) (SH group), combination of normal saline, hydroxyethyl starch and glutamine (SHG group) in resuscitation. The ratio of normal saline to HES in the SH and SHG groups was 3:1. The glutamine (20% glutamine dipeptide, 100 mL/d) was supplemented into the resuscitation liquid in the SHG group. Complications and outcomes including respiratory and abdominal infection, sepsis, abdominal hemorrhage, intra-abdominal hypertension, abdominal compartment syndrome (ACS), renal failure, acute respiratory distress syndrome (ARDS), multiple organ dysfunction syndrome (MODS), operation intervention, length of intensive care unit stay, length of hospital stay, and mortality at 60 d were compared. Moreover, blood oxygen saturation (SpO 2 ), gastric intramucosal pH value (pHi), intra-abdominal pressure (IAP), inflammation cytokines, urine lactulose/mannitol (L/M) ratio, and serum endotoxin were investigated to evaluate the inflammatory reaction and gut barrier. RESULTS: Compared to the NS group, patients in the SH and SHG groups accessed the endpoint more quickly (3.9 ± 0.23 d and 4.1 ± 0.21 d vs 5.8 ± 0.25 d, P < 0.05) with less fluid volume (67.26 ± 28.53 mL/kg/d, 61.79 ± 27.61 mL/kg per day vs 85.23 ± 21.27 mL/kg per day, P < 0.05). Compared to the NS group, incidence of renal dysfunction, ARDS, MODS and ACS in the SH and SHG groups was obviously lower. Furthermore, incidence of respiratory and abdominal infection was significantly decreased in the SH and SHG groups, while no significant difference in sepsis was seen. Moreover, less operation time was needed in the SH and SHG group than the NS group, but展开更多
AIM： To investigate the effect of delayed ethyl pyruvate （EP） delivery on distant organ injury, survival time and serum high mobility group box 1 （HMGB1） levels in rats with experimental severe acute pancreatitis...AIM： To investigate the effect of delayed ethyl pyruvate （EP） delivery on distant organ injury, survival time and serum high mobility group box 1 （HMGB1） levels in rats with experimental severe acute pancreatitis （SAP）. METHODS： A SAP model was induced by retrograde injection of artificial bile into the pancreatic ducts of rats. Animals were divided randomly into three groups （n = 32 in each group）： sham group, SAP group and delayed EP treatment group. The rats in the delayed EP treatment group received EP （30 mg/kg） at 12 h, 18 h and 30 h after induction of SAP. Animals were sacrificed, and samples were obtained at 24 h and 48 h after induction of SAP. Serum HMGB1, aspartate arninotransferase （AST）, alanine arninotransferase （ALT）, blood urea nitrogen （BUN）, and creatinine （Cr） levels were measured. Lung wet-to-dry-weight （W/D） ratios and histological scores were calculated to evaluate lung injury. Additional experiments were performed between SAP and delayed EP treatment groups to study the influence of EP on survival times of SAP rats. RESULTS： Delayed EP treatment significantly reduced serum HMGB1 levels, and protected against liver, renal and lung injury with reduced lung W/D ratios （8.22 ±0.42 vs 9.76 ± 0.45, P 〈 0.01）, pulmonary histological scores （7.1 ± 0.7 vs 8.4 ± 1.1, P 〈 0.01）, serum AST （667 ± 103 vs 1 368 ± 271, P 〈 0.01）, ALT （446 ± 91 vs 653 ± 98, P 〈 0.01） and Cr （1.2 ± 0.3 vs 1.8 ± 0.3, P 〈 0.01） levels. SAP rats had a median survival time of 44 h. Delayed EP treatment significantly prolonged median survival time to 72 h （P 〈 0.01）. CONCLUSION： Delayed EP therapy protects against distant organ injury and prolongs survival time via reduced serum HMGBllevels in rats with experimental SAP. EP may potentially serve as an effective new therapeutic option against the inflammatory response and multiple organ dysfunction syndrome （MODS） in SAP patients.展开更多
BACKGROUND: Toll-like receptor 2 and 4 (TLR2/4) may play important roles in ischemia-reperfusion (I/R) injury, and N-acetylcysteine (NAC) can prevent the generation of reactive oxygen species (ROS) induced by I/R inju...BACKGROUND: Toll-like receptor 2 and 4 (TLR2/4) may play important roles in ischemia-reperfusion (I/R) injury, and N-acetylcysteine (NAC) can prevent the generation of reactive oxygen species (ROS) induced by I/R injury. This study aimed to investigate the changes in TLR2/4 gene expression in the liver and lung after I/R injury with or without NAC pretreatment. METHODS: BALB/c mice were used in a model of partial hepatic I/R injury and randomly assigned to a sham-operated control group (SH), a hepatic ischemia/reperfusion group (I/R) or a NAC pretreated, hepatic I/R group (I/R-NAC). The levels of TNF-alpha in the portal vein and plasma alanine aminotransferase (ALT) were measured at 1 and 3 hours after reperfusion. The lung wet-to-dry ratio was measured, and the expression of TLR2/4 mRNA and protein in the liver and lung were assessed with RT-PCR and Western blotting at the same time points. RESULTS: Compared with the I/R group, the expression of TLR2/4 mRNA and protein in the liver and lung in the I/R-NAC group was decreased at the same time point (P<0.05). The levels of portal vein TNF-a and plasma ALT increased continuously in the l/R group at I and 3 hours of reperfusion compared with the SH group; however, they declined significantly in the group pretreated with NAC (P<0.05). The extent of lung edema was relieved in the I/R-NAC group compared with the I/R group (P<0.05). CONCLUSIONS: TLR2/4 was activated in the liver and lung in the process of partial hepatic I/R injury. NAC inhibited the activation of TLR2/4 and the induction of TNF-alpha resulting from I/R injury via modulating the redox state, thus it may mitigate liver and lung injury following partial hepatic I/R in mice.展开更多
AIM: To investigate the persistence of side population (SP) cells in pancreatic cancer and their role and mechanism in the drug resistance. METHODS: The presentation of side population cells in pancreatic cancer cell ...AIM: To investigate the persistence of side population (SP) cells in pancreatic cancer and their role and mechanism in the drug resistance. METHODS: The presentation of side population cells in pancreatic cancer cell line PANC-1 and its proportion change when cultured with Gemcitabine, was detected by Hoechst 33342 staining and FACS analysis. The expression of ABCB1 and ABCG2 was detected by real- time PCR in either SP cells or non-SP cells. RESULTS: SP cells do exist in PANC-1, with a median of 3.3% and a range of 2.1-8.7%. After cultured with Gemcitabine for 3 d, the proportion of SP cells increased significantly (3.8% ± 1.9%, 10.7% ± 3.7%, t = 4.616, P = 0.001 < 0.05). ABCB1 and ABCG2 expressed at higher concentrations in SP as compared with non-SP cells (ABCB1: 1.15 ± 0.72, 5.82 ± 1.16, t = 10.839, P = 0.000 < 0.05; ABCG2: 1.16 ± 0.75, 5.48 ± 0.94, t = 11.305, P = 0.000 < 0.05), which may contribute to the efflux of fluorescent staining and drug resistance. CONCLUSION: SP cells with inherently high resistance to chemotherapeutic agents do exist in pancreatic cancers, which may be candidate cancer stem cells contributing to the relapse of the tumor.展开更多
BACKGROUND: Toll-like receptor (TLR) 2/4 might play important roles in mediating proinflammatory cytokine synthesis and release. And nitric oxide (NO) has been used to treat acute respiratory distress syndrome (ARDS)....BACKGROUND: Toll-like receptor (TLR) 2/4 might play important roles in mediating proinflammatory cytokine synthesis and release. And nitric oxide (NO) has been used to treat acute respiratory distress syndrome (ARDS). This study aimed to investigate the changes in TLR2/4 gene expression in the lungs of rats with acute lung injury (ALI) complicated by acute hemorrhage necrotizing pancreatitis (AHNP) and the effect of NO on the TLR2/4 gene expression. METHODS: One hundred and ten SD male rats were randomly divided into sham-operated group ( n = 10) , AHNP group (n = 30) , chloroquine-treated group ( n = 30) , and L-Arg-treated group (n =40). The lungs were dissected for lung histological scoring, and bronchoalveolar lavages were harvested for lung injury indexing. TLR2/4 mRNA expression in the lungs was measured by RT-PCR. RESULTS: TLR2/4mRNA was detected in the lungs with low values in the sham-operated group (0.016±0. 210E-2, 0.112 ±0.750E-2) , but it was markedly increased at 3 hours in the AHNP group (0.787±0.751E-2, 1.512 ±1.794E-2) , peaking at 12 hours (1.113 ±6.141E-2, 2.957±2.620E-2; P <0.05 or P <0.01). When lung injuries were aggravated, TNF-α concentrations in the lungs were increased, but NO concentrations were decreased ( P < 0.05 or P < 0.01 ) . When TLR2/4mRNA was inhibited by CQ (3h: 0.313 ± 5.491E-2, 0.005 ±1.419E-3 ; 6h: 0.488 ±7.442E-2, 0.010 ± 1.518E-3; 12h: 0.883 ± 8.911E-2, 0.024 ± 2.760E-3; P< 0.05 or P <0.01) , lung injuries were relieved. NO concentrations in the lungs were increased but TNF-α concentrations were decreased (P <0. 05 or P <0.01). When the rats with AHNP were treated with L-Arg, TLR2/4mRNA expression in the lungs could be effectively inhibited (50mg-T: 0.656 ±3. 977E-2, 1. 501 ±6.111E-2; 100mg-T: 0.260± 0.891E-2, 0.732 ±5.135E-2; 200mg-T: 0.126 ±0.914E-2, 0.414 ± 1.678E-2; 400mg-T: 0.091 ±0.399E-2, 0.287 ± 0.176E-2; P <0.05 or P <0. 01) and lung injuries were relieved. At the same time, NO concentrations in the lungs were markedly increased, but TNF-α 展开更多
BACKGROUND:The surgical step-up approach often requires multiple debridements and might not be suitable for infected pancreatic necrosis(IPN)patients with various abscesses or no safe route for percutaneous catheter d...BACKGROUND:The surgical step-up approach often requires multiple debridements and might not be suitable for infected pancreatic necrosis(IPN)patients with various abscesses or no safe route for percutaneous catheter drainage(PCD).This case-control study aimed to investigate the safety and effectiveness of one-step laparoscopic pancreatic necrosectomy(LPN)in treating IPN.METHODS:This case-control study included IPN patients undergoing one-step LPN or surgical step-up in our center from January 2015 to December 2020.The short-term and long-term complications after surgery,length of hospital stay,and postoperative ICU stays in both groups were analyzed.Univariate and multivariate logistic regression analyses were performed to explore the risk factors of major complications or death.RESULTS:A total of 53 IPN patients underwent one-step LPN and 37 IPN patients underwent surgical step-up approach in this study.There was no significant difference in the incidence of death,major complications,new-onset diabetes,or new-onset pancreatic exocrine insufficiency between the two groups.However,the length of hospital stay in the one-step LPN group was significantly shorter than that in the surgical step-up group.Univariate regression analysis showed that the surgical approach(one-step/step-up)was not the risk factor for major complications or death.Multivariate logistic regression analysis indicated that computed tomography(CT)severity index,American Society of Anesthesiologists(ASA)class IV,and white blood cell(WBC)were the significant risk factors for major complications or death.CONCLUSION:One-step LPN is as safe and effective as the surgical step-up approach for treating IPN patients,and reduces total hospital stay.展开更多
AIM： To investigate the role of nitric oxide （NO） in Tolllike receptor 2 （TLR2）/4mRNA expression in livers of acute hemorrhagic necrotizing pancreatitis （AHNP） rats. METHODS： One hundred and ten SD male rats w...AIM： To investigate the role of nitric oxide （NO） in Tolllike receptor 2 （TLR2）/4mRNA expression in livers of acute hemorrhagic necrotizing pancreatitis （AHNP） rats. METHODS： One hundred and ten SD male rats were randomly divided into sham-operated group （n = 10）, AHNP group （n = 30）, chloroquine （CQ）-treated group （n = 30） and L-Arg-treated group （n = 40）. TLR2/4mRNA expression in the liver of AHNP rats was measured by RT-PCR. RESULTS： Expression of TLR2/4mRNA could be detected in the liver of AHNP rats in sham-operated group （0.155E-5±0.230E-6 and 0.115E-2±0.545E-4）, but was markedly increased at 3 h in AHNP group （0.197E-2±0.114E-3 and 0.175±0.349E-2） peaking at 12 h （0.294E-2 ± 0.998E-4 and 2.673 ± 2.795E-2, P〈 0.01）. Hepatic injuries were aggravated, TNF-α concentration in the liver was increased and NO concentration was decreased （P〈 0.05 or P〈 0.01）. When TLR2/4mRNA expression was inhibited by CQ （3 h： 1.037E-4±3.299E-6 and 0.026±3.462E-3; 6 h： 1.884E-4±4.679E-6 and 0.108±6.115E-3; 12 h： 2.443E-4±7.714E-6 and 0.348±6.807E-3; P 〈 0.01）, hepatic injuries were relieved, NO concentration in the liver was increased and TNF-α concentration was decreased （P〈0.05 or P〈0.01）. When rats with AHNP were treated with L-Arg, TLR2/4mRNA expression in the liver could be effectively inhibited （50 mg-T： 0.232E-2±0.532E-4 and 0.230±6.883E-3; 100 mg-T： 0.210E-2± 1.691E-4 and 0.187±0.849E-2; 200 mg-T： 0.163E-2±0.404E-4 and 0.107±0.195E-2; 400 mg-T： 0.100E-2±0.317E-4 and 0.084±0.552E-2; P〈0.01） and hepatic injuries were relieved. At the same time, NO concentration in the liver was markedly increased and TNF-α concentration was decreased （P〈0.05 or P〈O.OI）, CONCLUSION： The expression of TLR2/4mRNA is increased and hepatic injuries are aggravated in the liver of AHNP rats. TLR2/4mRNA gene expression in the liver of AHNP rats can be markedly inhibited by NO, leading to the relief of hepatic injuries.展开更多
BACKGROUND: The pancreas has a strong regeneration potential in mammals. Previous studies suggested that pancreas regeneration is correlated with proliferation and differentiation of pancreatic stem cells, but the fie...BACKGROUND: The pancreas has a strong regeneration potential in mammals. Previous studies suggested that pancreas regeneration is correlated with proliferation and differentiation of pancreatic stem cells, but the field of pancreatic stem cells is still in its infancy. This study was undertaken to detect the expression of pancreas/duodenal homeobox-1 (PDX-1) and proliferation of pancreatic duct epithelial cells in remnant pancreas during regeneration after partial pancreatectomy in rats, and characterize the source of pancreatic stem cells. METHODS: Partial pancreatectomy (90%) was performed on four- to five-week-old Sprague-Dawley rats, and duct epithelial cells and acinar cells were detected by immunohistochemical staining and scored using the 5-bromo-2-deoxyuridine (BrdU) labelling index at various time points. Western blotting and reverse transcriptase-polymerase chain reaction (RT-PCR) were used to assess the expression of PDX-1 protein and mRNA, respectively. RESULTS: At 24 hours after partial pancreatectomy, proliferation started in the main, large and small duct cells, and persisted in small duct cells to day 5. The experimental and control groups were significantly different (P<0.001). BrdU-positive acinar cells were greatly increased and reached a peak on day 5. PDX-1 protein was only faintly detectable in pancreatic ductal cells on day I after partial pancreatectomy. On days 2 and 3, a 2-3 fold increase in PDX-1 protein was observed, corresponding to the characteristic 42 kD protein in Western blotting. The operated and sham-operated groups also differed significantly (P<0.05). PDX-1 protein expression on days 5 and 7 after operation did not differ from that of the control group. RT-PCR revealed that PDX-1 mRNA expression did not significantly differ between the operated group and the sham-operated group at various time points. CONCLUSIONS: Pancreatic stem cells in pancreatic ductal epithelial cells are involved in the regeneration of remnant pancreas and the expression of PDX-1 in ductal cells is due 展开更多
AIM： To study the correlations of Pancreas duodenal homeobox-1 with pancreatic cancer characteristics, including pathological grading, TNM grading, tumor metastasis and tumor cell proliferation. METHODS： Reverse tra...AIM： To study the correlations of Pancreas duodenal homeobox-1 with pancreatic cancer characteristics, including pathological grading, TNM grading, tumor metastasis and tumor cell proliferation. METHODS： Reverse transcriptase-polymerase chain reaction （RT-PCR） was used to detect PDX-1 mRNA expression in pancreatic cancer tissue and normal pancreatic tissue. The expression of PDX-1 protein was measured by Western blot and immunohistochemistry. Immunohistochemistry was also used to detect proliferative cell nuclear antigen （PCNA）. Correlations of PDX-1 with pancreatic cancer characteristics, including pathological grading, TNM grading, tumor metastasis and tumor cell proliferation, were analyzed by using χ^2 test. RESULTS： Immunohistochemistry showed that 41.1% of pancreatic cancers were positive for PDX-1 expression, but normal pancreatic tissue except islets showed no staining for PDX-1. In consistent with the result of imunohistochemistry, Western blot showed that 37.5% of pancreatic cancers were positive for PDX-1. RT-PCR showed that PDX-1 expression was significantly higher in pancreatic cancer tissues than normal pancreatic tissues （2^-3.56±0.35 vs 2^-8.76±0.14, p 〈 0.01）. Lymph node metastasis （P 〈 0.01）, TNM grading （P 〈 0.05）, pathological grading （P 〈 0.05） and tumor cell proliferation （P 〈 0.01） were significantly correlated with PDX-1 expression levels. CONCLUSION： PDX-1 is re-expressed in pancreatic cancer, and PDX-l-positive pancreatic cancer cells show more malignant potential compared to PDX-l-negative cells. Therefore, PDX-l-positive cells may be tumor stemcells and PDX-1 may act as alternate surface marker of pancreatic cancer stem cells.展开更多
Tourism can have both positive and negative outcomes for residents in tourism destinations, It is a good method to analyze the status of tourism impact by means of investigating residents＇ perceptions of it. Various ...Tourism can have both positive and negative outcomes for residents in tourism destinations, It is a good method to analyze the status of tourism impact by means of investigating residents＇ perceptions of it. Various methods have been used in previous authoritative studies. However, owing to inherent imprecision, difficulties always exist in some conventional methodologies when describing the interpretation of linguistic or measured uncertainties for real-world randoln phenomena. The purpose of this research is to present the fuzzy synthetic evaluation method to investigate residents＇ perceptions of tourisln impacts. At first, basic attributes and a hierarchical framework of tourism impacts are defined and formed. Secondly, the weighted vectors are determined according to the knowledge and experience of experts. Thirdly, the weighted evaluation matrices are aggregated to get the fuzzy sets of tourism impacts. In the last stage, the final fuzzy sets are defuzzified to get the rank of the residents＇ perceptions of tourism impacts. A case study in Jiuzhaigou National Park of China is provided to demonstrate the application of this method.展开更多
AIM: To establish a method for the reversible immortalization of human hepatocytes, which may offer a good and safe source of hepatocytes for practical applications.
BACKGROUND:Emerging evidence suggests that pancreatic adenocarcinoma is hierarchically organized and sustained by pancreatic cancer stem cells.Furthermore,elimination of these cells is possible and therapeutically rel...BACKGROUND:Emerging evidence suggests that pancreatic adenocarcinoma is hierarchically organized and sustained by pancreatic cancer stem cells.Furthermore,elimination of these cells is possible and therapeutically relevant.This study aimed to investigate the expression patterns of pancreatic cancer stem cell surface markers CD44,CD24 and ESA in pancreatic adenocarcinoma cell lines and explore the influence of their local microenvironment.METHODS:Flow cytometry was used to analyze the expression patterns of CD44,CD24 and ESA in five pancreatic adenocarcinoma cell lines (PANC-1,PC-2,MIA-Paca-2,AsPC-1 and BxPC-3).In addition,the capacity for sphereformation in serum-free medium of four cell lines (PANC-1,PC-2,MIA-Paca-2 and BxPC-3) was assessed.Then,the same assays were performed when tumor cell spheres were developed.The role of sonic hedgehog (SHH) in cell spheres from PANC-1 and MIA-Paca-2 were also assessed by RT-PCR.RESULTS:CD44 and CD24 were detected in PANC-1.Only CD44 expression was detected in PC-2,MIA-Paca-2 and AsPC-1.CD44,CD24 and ESA were all detected in BxPC-3.Tumor cell spheres developed in PANC-1 and MIA-Paca-2 in serumfree medium.This was accompanied by an increase in CD24 expression and a decrease in CD44 expression in PANC-1.Interestingly,the expression of CD44 and CD24 returned to initial levels once the medium was changed back from serumfree to serum-containing medium.No significant change in the expression of CD44 was detected in MIA-Paca-2.Furthermore,the relative quantification of SHH mRNA in PANC-1 cell spheres was significantly higher than that in cells cultured in the serum-containing medium.CONCLUSION:The expression patterns of the pancreatic cancer stem cell surface markers CD44,CD24 and ESA were diverse in different pancreatic adenocarcinoma cell lines and changed with their local microenvironment.展开更多
AIM: To observe whether pancreatic and duodenal homeobox factor-1 enhances the differentiation of pancreatic ductal epithelial cells into insulin-producing cells in vitro. METHODS: Rat pancreatic tissue was submitted ...AIM: To observe whether pancreatic and duodenal homeobox factor-1 enhances the differentiation of pancreatic ductal epithelial cells into insulin-producing cells in vitro. METHODS: Rat pancreatic tissue was submitted to digestion by collegenase, ductal epithelial cells were separated by density gradient centrifugation and then cultured in RPMI1640 medium with 10% fetal bovine serum. After 3-5 passages, the cells were incubated in a six-well plate for 24 h before transfection of recombination plasmid XlHbox8VP16. Lightcycler quantitative real-time RT-PCR was used to detect the expression of PDX-1 and insulin mRNA in pancreatic epithelial cells. The expression of PDX-1 and insulin protein was analyzed by Western blotting. Insulin secretion was detected by radioimmunoassay. Insulin- producing cells were detected by dithizone-staining. RESULTS: XlHbox8 mRNA was expressed in pancreatic ductal epithelial cells. PDX-1 and insulin mRNA as well as PDX-1 and insulin protein were signifi cantly increased in the transfected group. The production and insulin secretion of insulin-producing cells differentiated from pancreatic ductal epithelial cells were higher than those of the untransfected cells in vitro with a significant difference (1.32 ± 0.43 vs 3.48 ± 0.81, P < 0.01 at 5.6 mmol/L; 4.86 ± 1.15 vs 10.25 ± 1.32, P < 0.01 at 16.7 mmol/L). CONCLUSION: PDX-1 can differentiate rat pancreaticductal epithelial cells into insulin-producing cells in vitro. In vitro PDX-1 transfection is a valuable strategy for increasing the source of insulin-producing cells.展开更多
基金supported by the National Key Research and Development Program of China(2022YFA0912300)the Agricultural Science and Technology Innovation Program(ASTIP)Tianjin Synthetic Biotechnology Innovation Capacity Improvement Project,China(TSBICIP-CXRC-067)。
文摘扫描电子显微镜(scanning electron microscope,SEM)是表征高分子材料微观结构及其组成信息重要的手段之一,具有操作简便、信号电子种类多样且对样品损伤较小等特点.本文系统阐述了SEM的工作原理,通过与透射电子显微镜(transmission electron microscope,TEM)进行比较,突出了其优势与特色.详细讨论了该技术的测试方法,包括样品制备、仪器参数设定、操作技巧与图像处理,并揭示了获得高质量SEM图像的关键技术.介绍了SEM不同的信号电子成像、SEM与其他仪器联用及SEM原位分析技术在高分子材料表征中的应用与进展.最后,对SEM的发展趋势进行了展望.
文摘仿生偏振导航是近年来兴起的一种新原理导航方式,对天空光进行成像可以获得更为丰富的天空散射光的偏振信息以及分布特征,有利于提高偏振导航传感器的精度和抗干扰能力。根据现有的Stokes参量测量偏振光的原理以及成像装置的噪声模型,对基于Stokes参量法的偏振角度测量噪声进行了建模,并根据模型进行了仿真分析。仿真结果表明:提高相机的信噪比(SNR)能够显著提高偏振成像的质量,当相机的SNR大于44 d B时,天空偏振角度的测量标准差将优于1°/像素;得到了0°,60°,120°和0°,45°,90°检偏器分布模式下对不同偏振角度的入射光测量噪声的统计分布特征。尽管0°,60°,120°的检偏器布置方案相对于0°,45°,90°的检偏器布置方案有着更大的计算复杂度,但在使用相同信噪比相机的情况下,该布置方案的噪声更小。该结论将对天空偏振光成像装置的构建及其误差分析与补偿技术提供参考。
基金Supported by National Science Foundation Committee of China,No. 30600594 and 30972900the Fundamental Research Funds for the Central Universities of China, No. 2011JC046
文摘AIM: To compare effects of different resuscitation fluid on microcirculation, inflammation, intestinal barrier and clinical results in severe acute pancreatitis (SAP). METHODS: One hundred and twenty patients with SAP were enrolled at the Pancreatic Disease Institute between January 2007 and March 2010. The patients were randomly treated with normal saline (NS group), combination of normal saline and hydroxyethyl starch (HES) (SH group), combination of normal saline, hydroxyethyl starch and glutamine (SHG group) in resuscitation. The ratio of normal saline to HES in the SH and SHG groups was 3:1. The glutamine (20% glutamine dipeptide, 100 mL/d) was supplemented into the resuscitation liquid in the SHG group. Complications and outcomes including respiratory and abdominal infection, sepsis, abdominal hemorrhage, intra-abdominal hypertension, abdominal compartment syndrome (ACS), renal failure, acute respiratory distress syndrome (ARDS), multiple organ dysfunction syndrome (MODS), operation intervention, length of intensive care unit stay, length of hospital stay, and mortality at 60 d were compared. Moreover, blood oxygen saturation (SpO 2 ), gastric intramucosal pH value (pHi), intra-abdominal pressure (IAP), inflammation cytokines, urine lactulose/mannitol (L/M) ratio, and serum endotoxin were investigated to evaluate the inflammatory reaction and gut barrier. RESULTS: Compared to the NS group, patients in the SH and SHG groups accessed the endpoint more quickly (3.9 ± 0.23 d and 4.1 ± 0.21 d vs 5.8 ± 0.25 d, P < 0.05) with less fluid volume (67.26 ± 28.53 mL/kg/d, 61.79 ± 27.61 mL/kg per day vs 85.23 ± 21.27 mL/kg per day, P < 0.05). Compared to the NS group, incidence of renal dysfunction, ARDS, MODS and ACS in the SH and SHG groups was obviously lower. Furthermore, incidence of respiratory and abdominal infection was significantly decreased in the SH and SHG groups, while no significant difference in sepsis was seen. Moreover, less operation time was needed in the SH and SHG group than the NS group, but
基金The National Natural Science Foundation of China, No. 30600593
文摘AIM： To investigate the effect of delayed ethyl pyruvate （EP） delivery on distant organ injury, survival time and serum high mobility group box 1 （HMGB1） levels in rats with experimental severe acute pancreatitis （SAP）. METHODS： A SAP model was induced by retrograde injection of artificial bile into the pancreatic ducts of rats. Animals were divided randomly into three groups （n = 32 in each group）： sham group, SAP group and delayed EP treatment group. The rats in the delayed EP treatment group received EP （30 mg/kg） at 12 h, 18 h and 30 h after induction of SAP. Animals were sacrificed, and samples were obtained at 24 h and 48 h after induction of SAP. Serum HMGB1, aspartate arninotransferase （AST）, alanine arninotransferase （ALT）, blood urea nitrogen （BUN）, and creatinine （Cr） levels were measured. Lung wet-to-dry-weight （W/D） ratios and histological scores were calculated to evaluate lung injury. Additional experiments were performed between SAP and delayed EP treatment groups to study the influence of EP on survival times of SAP rats. RESULTS： Delayed EP treatment significantly reduced serum HMGB1 levels, and protected against liver, renal and lung injury with reduced lung W/D ratios （8.22 ±0.42 vs 9.76 ± 0.45, P 〈 0.01）, pulmonary histological scores （7.1 ± 0.7 vs 8.4 ± 1.1, P 〈 0.01）, serum AST （667 ± 103 vs 1 368 ± 271, P 〈 0.01）, ALT （446 ± 91 vs 653 ± 98, P 〈 0.01） and Cr （1.2 ± 0.3 vs 1.8 ± 0.3, P 〈 0.01） levels. SAP rats had a median survival time of 44 h. Delayed EP treatment significantly prolonged median survival time to 72 h （P 〈 0.01）. CONCLUSION： Delayed EP therapy protects against distant organ injury and prolongs survival time via reduced serum HMGBllevels in rats with experimental SAP. EP may potentially serve as an effective new therapeutic option against the inflammatory response and multiple organ dysfunction syndrome （MODS） in SAP patients.
基金This work was supported by a grant from theNational Natural Science Foundation of China(No.30200272).
文摘BACKGROUND: Toll-like receptor 2 and 4 (TLR2/4) may play important roles in ischemia-reperfusion (I/R) injury, and N-acetylcysteine (NAC) can prevent the generation of reactive oxygen species (ROS) induced by I/R injury. This study aimed to investigate the changes in TLR2/4 gene expression in the liver and lung after I/R injury with or without NAC pretreatment. METHODS: BALB/c mice were used in a model of partial hepatic I/R injury and randomly assigned to a sham-operated control group (SH), a hepatic ischemia/reperfusion group (I/R) or a NAC pretreated, hepatic I/R group (I/R-NAC). The levels of TNF-alpha in the portal vein and plasma alanine aminotransferase (ALT) were measured at 1 and 3 hours after reperfusion. The lung wet-to-dry ratio was measured, and the expression of TLR2/4 mRNA and protein in the liver and lung were assessed with RT-PCR and Western blotting at the same time points. RESULTS: Compared with the I/R group, the expression of TLR2/4 mRNA and protein in the liver and lung in the I/R-NAC group was decreased at the same time point (P<0.05). The levels of portal vein TNF-a and plasma ALT increased continuously in the l/R group at I and 3 hours of reperfusion compared with the SH group; however, they declined significantly in the group pretreated with NAC (P<0.05). The extent of lung edema was relieved in the I/R-NAC group compared with the I/R group (P<0.05). CONCLUSIONS: TLR2/4 was activated in the liver and lung in the process of partial hepatic I/R injury. NAC inhibited the activation of TLR2/4 and the induction of TNF-alpha resulting from I/R injury via modulating the redox state, thus it may mitigate liver and lung injury following partial hepatic I/R in mice.
基金The National Natural Science Foundation of China, No. 30571817
文摘AIM: To investigate the persistence of side population (SP) cells in pancreatic cancer and their role and mechanism in the drug resistance. METHODS: The presentation of side population cells in pancreatic cancer cell line PANC-1 and its proportion change when cultured with Gemcitabine, was detected by Hoechst 33342 staining and FACS analysis. The expression of ABCB1 and ABCG2 was detected by real- time PCR in either SP cells or non-SP cells. RESULTS: SP cells do exist in PANC-1, with a median of 3.3% and a range of 2.1-8.7%. After cultured with Gemcitabine for 3 d, the proportion of SP cells increased significantly (3.8% ± 1.9%, 10.7% ± 3.7%, t = 4.616, P = 0.001 < 0.05). ABCB1 and ABCG2 expressed at higher concentrations in SP as compared with non-SP cells (ABCB1: 1.15 ± 0.72, 5.82 ± 1.16, t = 10.839, P = 0.000 < 0.05; ABCG2: 1.16 ± 0.75, 5.48 ± 0.94, t = 11.305, P = 0.000 < 0.05), which may contribute to the efflux of fluorescent staining and drug resistance. CONCLUSION: SP cells with inherently high resistance to chemotherapeutic agents do exist in pancreatic cancers, which may be candidate cancer stem cells contributing to the relapse of the tumor.
基金This work was supported by a grant from the National Natural Science Foundation of China (No. 30200272).
文摘BACKGROUND: Toll-like receptor (TLR) 2/4 might play important roles in mediating proinflammatory cytokine synthesis and release. And nitric oxide (NO) has been used to treat acute respiratory distress syndrome (ARDS). This study aimed to investigate the changes in TLR2/4 gene expression in the lungs of rats with acute lung injury (ALI) complicated by acute hemorrhage necrotizing pancreatitis (AHNP) and the effect of NO on the TLR2/4 gene expression. METHODS: One hundred and ten SD male rats were randomly divided into sham-operated group ( n = 10) , AHNP group (n = 30) , chloroquine-treated group ( n = 30) , and L-Arg-treated group (n =40). The lungs were dissected for lung histological scoring, and bronchoalveolar lavages were harvested for lung injury indexing. TLR2/4 mRNA expression in the lungs was measured by RT-PCR. RESULTS: TLR2/4mRNA was detected in the lungs with low values in the sham-operated group (0.016±0. 210E-2, 0.112 ±0.750E-2) , but it was markedly increased at 3 hours in the AHNP group (0.787±0.751E-2, 1.512 ±1.794E-2) , peaking at 12 hours (1.113 ±6.141E-2, 2.957±2.620E-2; P <0.05 or P <0.01). When lung injuries were aggravated, TNF-α concentrations in the lungs were increased, but NO concentrations were decreased ( P < 0.05 or P < 0.01 ) . When TLR2/4mRNA was inhibited by CQ (3h: 0.313 ± 5.491E-2, 0.005 ±1.419E-3 ; 6h: 0.488 ±7.442E-2, 0.010 ± 1.518E-3; 12h: 0.883 ± 8.911E-2, 0.024 ± 2.760E-3; P< 0.05 or P <0.01) , lung injuries were relieved. NO concentrations in the lungs were increased but TNF-α concentrations were decreased (P <0. 05 or P <0.01). When the rats with AHNP were treated with L-Arg, TLR2/4mRNA expression in the lungs could be effectively inhibited (50mg-T: 0.656 ±3. 977E-2, 1. 501 ±6.111E-2; 100mg-T: 0.260± 0.891E-2, 0.732 ±5.135E-2; 200mg-T: 0.126 ±0.914E-2, 0.414 ± 1.678E-2; 400mg-T: 0.091 ±0.399E-2, 0.287 ± 0.176E-2; P <0.05 or P <0. 01) and lung injuries were relieved. At the same time, NO concentrations in the lungs were markedly increased, but TNF-α
基金This work was supported by the Clinical Research Physician Program of Tongji Medical College,Huazhong University of Science and Technology。
文摘BACKGROUND:The surgical step-up approach often requires multiple debridements and might not be suitable for infected pancreatic necrosis(IPN)patients with various abscesses or no safe route for percutaneous catheter drainage(PCD).This case-control study aimed to investigate the safety and effectiveness of one-step laparoscopic pancreatic necrosectomy(LPN)in treating IPN.METHODS:This case-control study included IPN patients undergoing one-step LPN or surgical step-up in our center from January 2015 to December 2020.The short-term and long-term complications after surgery,length of hospital stay,and postoperative ICU stays in both groups were analyzed.Univariate and multivariate logistic regression analyses were performed to explore the risk factors of major complications or death.RESULTS:A total of 53 IPN patients underwent one-step LPN and 37 IPN patients underwent surgical step-up approach in this study.There was no significant difference in the incidence of death,major complications,new-onset diabetes,or new-onset pancreatic exocrine insufficiency between the two groups.However,the length of hospital stay in the one-step LPN group was significantly shorter than that in the surgical step-up group.Univariate regression analysis showed that the surgical approach(one-step/step-up)was not the risk factor for major complications or death.Multivariate logistic regression analysis indicated that computed tomography(CT)severity index,American Society of Anesthesiologists(ASA)class IV,and white blood cell(WBC)were the significant risk factors for major complications or death.CONCLUSION:One-step LPN is as safe and effective as the surgical step-up approach for treating IPN patients,and reduces total hospital stay.
基金Supported by the National Natural Science Foundation of China,No.30200272
文摘AIM： To investigate the role of nitric oxide （NO） in Tolllike receptor 2 （TLR2）/4mRNA expression in livers of acute hemorrhagic necrotizing pancreatitis （AHNP） rats. METHODS： One hundred and ten SD male rats were randomly divided into sham-operated group （n = 10）, AHNP group （n = 30）, chloroquine （CQ）-treated group （n = 30） and L-Arg-treated group （n = 40）. TLR2/4mRNA expression in the liver of AHNP rats was measured by RT-PCR. RESULTS： Expression of TLR2/4mRNA could be detected in the liver of AHNP rats in sham-operated group （0.155E-5±0.230E-6 and 0.115E-2±0.545E-4）, but was markedly increased at 3 h in AHNP group （0.197E-2±0.114E-3 and 0.175±0.349E-2） peaking at 12 h （0.294E-2 ± 0.998E-4 and 2.673 ± 2.795E-2, P〈 0.01）. Hepatic injuries were aggravated, TNF-α concentration in the liver was increased and NO concentration was decreased （P〈 0.05 or P〈 0.01）. When TLR2/4mRNA expression was inhibited by CQ （3 h： 1.037E-4±3.299E-6 and 0.026±3.462E-3; 6 h： 1.884E-4±4.679E-6 and 0.108±6.115E-3; 12 h： 2.443E-4±7.714E-6 and 0.348±6.807E-3; P 〈 0.01）, hepatic injuries were relieved, NO concentration in the liver was increased and TNF-α concentration was decreased （P〈0.05 or P〈0.01）. When rats with AHNP were treated with L-Arg, TLR2/4mRNA expression in the liver could be effectively inhibited （50 mg-T： 0.232E-2±0.532E-4 and 0.230±6.883E-3; 100 mg-T： 0.210E-2± 1.691E-4 and 0.187±0.849E-2; 200 mg-T： 0.163E-2±0.404E-4 and 0.107±0.195E-2; 400 mg-T： 0.100E-2±0.317E-4 and 0.084±0.552E-2; P〈0.01） and hepatic injuries were relieved. At the same time, NO concentration in the liver was markedly increased and TNF-α concentration was decreased （P〈0.05 or P〈O.OI）, CONCLUSION： The expression of TLR2/4mRNA is increased and hepatic injuries are aggravated in the liver of AHNP rats. TLR2/4mRNA gene expression in the liver of AHNP rats can be markedly inhibited by NO, leading to the relief of hepatic injuries.
基金This study was supported by a grant from the National Natural Sciences Foundation of China (No. 30571817).
文摘BACKGROUND: The pancreas has a strong regeneration potential in mammals. Previous studies suggested that pancreas regeneration is correlated with proliferation and differentiation of pancreatic stem cells, but the field of pancreatic stem cells is still in its infancy. This study was undertaken to detect the expression of pancreas/duodenal homeobox-1 (PDX-1) and proliferation of pancreatic duct epithelial cells in remnant pancreas during regeneration after partial pancreatectomy in rats, and characterize the source of pancreatic stem cells. METHODS: Partial pancreatectomy (90%) was performed on four- to five-week-old Sprague-Dawley rats, and duct epithelial cells and acinar cells were detected by immunohistochemical staining and scored using the 5-bromo-2-deoxyuridine (BrdU) labelling index at various time points. Western blotting and reverse transcriptase-polymerase chain reaction (RT-PCR) were used to assess the expression of PDX-1 protein and mRNA, respectively. RESULTS: At 24 hours after partial pancreatectomy, proliferation started in the main, large and small duct cells, and persisted in small duct cells to day 5. The experimental and control groups were significantly different (P<0.001). BrdU-positive acinar cells were greatly increased and reached a peak on day 5. PDX-1 protein was only faintly detectable in pancreatic ductal cells on day I after partial pancreatectomy. On days 2 and 3, a 2-3 fold increase in PDX-1 protein was observed, corresponding to the characteristic 42 kD protein in Western blotting. The operated and sham-operated groups also differed significantly (P<0.05). PDX-1 protein expression on days 5 and 7 after operation did not differ from that of the control group. RT-PCR revealed that PDX-1 mRNA expression did not significantly differ between the operated group and the sham-operated group at various time points. CONCLUSIONS: Pancreatic stem cells in pancreatic ductal epithelial cells are involved in the regeneration of remnant pancreas and the expression of PDX-1 in ductal cells is due
基金Supported by the grants from the National Natural Science Foundation of China, No.30571817the PhD Programs Foundation of Ministry of Education of China, No. 20050487077
文摘AIM： To study the correlations of Pancreas duodenal homeobox-1 with pancreatic cancer characteristics, including pathological grading, TNM grading, tumor metastasis and tumor cell proliferation. METHODS： Reverse transcriptase-polymerase chain reaction （RT-PCR） was used to detect PDX-1 mRNA expression in pancreatic cancer tissue and normal pancreatic tissue. The expression of PDX-1 protein was measured by Western blot and immunohistochemistry. Immunohistochemistry was also used to detect proliferative cell nuclear antigen （PCNA）. Correlations of PDX-1 with pancreatic cancer characteristics, including pathological grading, TNM grading, tumor metastasis and tumor cell proliferation, were analyzed by using χ^2 test. RESULTS： Immunohistochemistry showed that 41.1% of pancreatic cancers were positive for PDX-1 expression, but normal pancreatic tissue except islets showed no staining for PDX-1. In consistent with the result of imunohistochemistry, Western blot showed that 37.5% of pancreatic cancers were positive for PDX-1. RT-PCR showed that PDX-1 expression was significantly higher in pancreatic cancer tissues than normal pancreatic tissues （2^-3.56±0.35 vs 2^-8.76±0.14, p 〈 0.01）. Lymph node metastasis （P 〈 0.01）, TNM grading （P 〈 0.05）, pathological grading （P 〈 0.05） and tumor cell proliferation （P 〈 0.01） were significantly correlated with PDX-1 expression levels. CONCLUSION： PDX-1 is re-expressed in pancreatic cancer, and PDX-l-positive pancreatic cancer cells show more malignant potential compared to PDX-l-negative cells. Therefore, PDX-l-positive cells may be tumor stemcells and PDX-1 may act as alternate surface marker of pancreatic cancer stem cells.
基金Under the auspices of Canadian International Development Agency Project (No. S-61562) Ecotourism Planning and Management in Dalian City of Dalian Science&Technology Bureau(No.2004B3SF171)
文摘Tourism can have both positive and negative outcomes for residents in tourism destinations, It is a good method to analyze the status of tourism impact by means of investigating residents＇ perceptions of it. Various methods have been used in previous authoritative studies. However, owing to inherent imprecision, difficulties always exist in some conventional methodologies when describing the interpretation of linguistic or measured uncertainties for real-world randoln phenomena. The purpose of this research is to present the fuzzy synthetic evaluation method to investigate residents＇ perceptions of tourisln impacts. At first, basic attributes and a hierarchical framework of tourism impacts are defined and formed. Secondly, the weighted vectors are determined according to the knowledge and experience of experts. Thirdly, the weighted evaluation matrices are aggregated to get the fuzzy sets of tourism impacts. In the last stage, the final fuzzy sets are defuzzified to get the rank of the residents＇ perceptions of tourism impacts. A case study in Jiuzhaigou National Park of China is provided to demonstrate the application of this method.
基金Supported by Major Scientific and Technological Project of Shandong Province,No.201221019Cisco Clinical Oncology Research Fund and Bayer Schering Cancer Research Fund,No.Y-B2012-011
文摘AIM: To establish a method for the reversible immortalization of human hepatocytes, which may offer a good and safe source of hepatocytes for practical applications.
基金supported by a grant from the National Natural Science Foundation of China(30801100)
文摘BACKGROUND:Emerging evidence suggests that pancreatic adenocarcinoma is hierarchically organized and sustained by pancreatic cancer stem cells.Furthermore,elimination of these cells is possible and therapeutically relevant.This study aimed to investigate the expression patterns of pancreatic cancer stem cell surface markers CD44,CD24 and ESA in pancreatic adenocarcinoma cell lines and explore the influence of their local microenvironment.METHODS:Flow cytometry was used to analyze the expression patterns of CD44,CD24 and ESA in five pancreatic adenocarcinoma cell lines (PANC-1,PC-2,MIA-Paca-2,AsPC-1 and BxPC-3).In addition,the capacity for sphereformation in serum-free medium of four cell lines (PANC-1,PC-2,MIA-Paca-2 and BxPC-3) was assessed.Then,the same assays were performed when tumor cell spheres were developed.The role of sonic hedgehog (SHH) in cell spheres from PANC-1 and MIA-Paca-2 were also assessed by RT-PCR.RESULTS:CD44 and CD24 were detected in PANC-1.Only CD44 expression was detected in PC-2,MIA-Paca-2 and AsPC-1.CD44,CD24 and ESA were all detected in BxPC-3.Tumor cell spheres developed in PANC-1 and MIA-Paca-2 in serumfree medium.This was accompanied by an increase in CD24 expression and a decrease in CD44 expression in PANC-1.Interestingly,the expression of CD44 and CD24 returned to initial levels once the medium was changed back from serumfree to serum-containing medium.No significant change in the expression of CD44 was detected in MIA-Paca-2.Furthermore,the relative quantification of SHH mRNA in PANC-1 cell spheres was significantly higher than that in cells cultured in the serum-containing medium.CONCLUSION:The expression patterns of the pancreatic cancer stem cell surface markers CD44,CD24 and ESA were diverse in different pancreatic adenocarcinoma cell lines and changed with their local microenvironment.
基金the grants from the National Natural Science Foundation of China, No.30571817the PhD Programs Foundation of Ministry of Education of China, No.20050487077
文摘AIM: To observe whether pancreatic and duodenal homeobox factor-1 enhances the differentiation of pancreatic ductal epithelial cells into insulin-producing cells in vitro. METHODS: Rat pancreatic tissue was submitted to digestion by collegenase, ductal epithelial cells were separated by density gradient centrifugation and then cultured in RPMI1640 medium with 10% fetal bovine serum. After 3-5 passages, the cells were incubated in a six-well plate for 24 h before transfection of recombination plasmid XlHbox8VP16. Lightcycler quantitative real-time RT-PCR was used to detect the expression of PDX-1 and insulin mRNA in pancreatic epithelial cells. The expression of PDX-1 and insulin protein was analyzed by Western blotting. Insulin secretion was detected by radioimmunoassay. Insulin- producing cells were detected by dithizone-staining. RESULTS: XlHbox8 mRNA was expressed in pancreatic ductal epithelial cells. PDX-1 and insulin mRNA as well as PDX-1 and insulin protein were signifi cantly increased in the transfected group. The production and insulin secretion of insulin-producing cells differentiated from pancreatic ductal epithelial cells were higher than those of the untransfected cells in vitro with a significant difference (1.32 ± 0.43 vs 3.48 ± 0.81, P < 0.01 at 5.6 mmol/L; 4.86 ± 1.15 vs 10.25 ± 1.32, P < 0.01 at 16.7 mmol/L). CONCLUSION: PDX-1 can differentiate rat pancreaticductal epithelial cells into insulin-producing cells in vitro. In vitro PDX-1 transfection is a valuable strategy for increasing the source of insulin-producing cells.
