In order to investigate the strength, structure and cell cytocompatibility of injectable thermosensitive chitosan (CS)/poly(vinyl alcohol) (PVA) composite hydrogel, chitosan hydrochloride solution was transferred to a neutral pH and mixed with different proportions of PVA, then the gelation time and strength of these different hydrogels were tested and spatial structures were observed under a scanning electron microscopy (SEM) after freeze-drying. The cytocompatibility of the hydrogels was evaluated through cytotoxicity test and three-dimensional culture with bone marrow mesenchymal stem cells. The results showed that the CS/PVA solution kept in liquid state at low temperature (0-4 degrees C) and turned into transparent elastomer about 15-20 min at 37 degrees C. Gelation time was prolonged, the strength increased and porous structure became dense with the PVA content increased in the mixed hydrogel. The cytotoxicity grades of these gels were from 0 to 1. Rabbit bone marrow mesenchymal stem cells could survive and proliferate in the gel within 3 weeks, and the gel had good cytocompatibility. It was concluded that thermosensitive CS/PVA composite hydrogel not only has interpenetrating network structure and better mechanical strength, but also has good cytocompatibility, and may be used as an injectable scaffold for tissue engineering.

Objective To investigate the composite of chitosan(CS) and polyvinyl alcohol (PVA) as scaffold carrier for rabbit chondrocytes nurture and growth.Methods The third passage of chondrocytes were seeded in CS/PVA gel scaffold and 24,48 and 72 h after which cytoactive and toxicity were determined by MTT respectively.After one,two and three weeks,the growing status and morphology of chondrocytes in CS/PVA gel were observed with scaning electron microscope (SEM) and laser confocal scanning fluorescence microscope (LCSM).Results The third passage of chondrocytes in CS/PVA gel scaffold remained high proliferation ability.MTT measuring cell activity and virulence,the result showed that the number of cells obviously increased with the time,with statistical significance of difference between each groups (P＜0.05),without side effect to cells by the material.Observation of scaning electron microscope and confocal laser scanning fluorescence microscope showed that chondrocytes grew well with the scaffold of CS/PVA gel.Conclusion CS/PVA mixed gel material can be used as scaffold for rabbit chondrocytes growing for repairing cartilages defect in tissue engineering.

Pancreatic cancer is characterized by high invasiveness,high malignancy and poor prognosis. Therefore,it is urgent to find biomarkers for early diagnosis and to develop targeting drugs for treatment of pancreatic cancer. MicroRNAs (miRNAs)are single-stranded,non-coding small RNA molecules with a length of 18-25 nucleotides and are highly expressed in pancreatic cancer. MiRNAs play important roles in cell proliferation,differentiation,apoptosis,invasion and metastasis,and are associated with adverse prognosis and resistance to chemotherapy in pancreatic cancer. As a new target for diagnosis and treatment of pancreatic cancer,miRNA-21 has become the hot spot of clinical research. This article reviewed the advances in studies on miRNA-21 in the pathogenesis,diagnosis and treatment of pancreatic cancer.

BACKGROUND:Bioactive glass, a multi-phase composite material, has good biological activity, bone conductivity and biocompatibility, but as a bone repair material it cannot be completely degraded, and has low mechanical strength that is insufficient.
OBJECTIVE:To design a kind of bioactive glasses/chitosan composite scaffold, and to investigate its physicochemical properties and cellcompatibility.
METHODS:Hydrochloric acid solution containing 2.0%chitosan was mixed withβ-glycerophosphate at a radio of 7:1 to prepare chitosan solution. Bioactive glasses of 0.5, 1.0, 1.5 g were added into the prepared chitosan solution, and the mass ratios of chitosan and bioactive glass were 2:1, 1:1, and 1:1.5 respectively. The composite materials were immersed and mineralized in simulated body fluid for 7 days.
RESULTS AND CONCLUSION:Scanning electron microscopy showed that the composite scaffold had an interconnected porous structure with the porosity of 89%and the pore size of 100-300μm;bioactive glasses dispersed in a needle shape between the chitosan scaffolds, arranged evenly, and were ful y wrapped tightly by the scaffolds. With the increase in mass of bioactive glass, the porosity of the composites decreased, but the fracture strength gradual y increased. There was a positive correlation between the composite porosity and fracture strength. X-ray diffraction and Fourier transform infrared spectroscopy confirmed that the composite scaffold appeared to have no changes in the nature of single materials, and differential scanning calorimetry analysis showed no mass loss at normal body temperature. After 3 days of mineralization, hydroxyapatite forming on the material surface gradual y grew up as a vil ous shape, and also significantly increased in number. After 7 days of mineralization, hydroxyapatite changed from a vil ous shape to a needle shape, the amount of hydroxyapatite was increased further, and many mineralized products were in a spherical shape.

ObjectiveTo investigate the feasibility of hTGF-β1 transfected bone mrrow mesenchymal stem cell (BMSCs) combined with calcium alginate gel in three dimensional condition to construct tissue engineering cartilage.MethodsRats BMSCs were obtained and cultured by whole bone marrow method,and then the third-generation cells were seeded into cell culture plate,and were divided into 3 groups:AdhTGF-β1 transfected group, Ad-EGFP transfected group and control group. The control group was added in common medium without any treatment while the other 2 groups were respectively added in serum-free medium containing Ad-hTGF-β1 or that containing Ad-EGFP.Seven days later,real-time fluorescent quantitation PCR and Western blot were employed for detecting the expression of TGF-β1.Then,the BMSCs which successfully transfected by Ad-hTGF-β1,were continually cultured in vitro.Andthe confound of cells-calcium alginate gel,the cell density was 1.0 × l07 per ml,were prepared and cultuered in constant temperature incubator.Ten days later,examine the morphous and proliferation of cell.Last,paraffin slice of the cell-gel confound was stained by HE,toluidine blue and Masson staining,while immunohistochemical for the secretion of collagen Ⅱ.ResultsSeven days after the transfection, real-time fluorescent quantitation PCR revealed that the average relative expression of TGF-β1 was:Ad-hTGF-β1 group 0.863,and Ad-EGFP group 0.183, the control group 0.180, and the expression difference of TGF-β1 was statistically diffence(P ＜0.05). Western blot proved strong TGF-β1 expression in Ad-hTGF-β1 group while it was detected a little in the other two groups. Globose cells were observed through inverted microscope in the calcium alginate gel.MTT proved the amount of cells were not statistically diffence (P ＞ 0.05) at different time point.HE staining proved amount cartilage lacuna formation in the gel, while the secretion of cartilage matrix were proved by toluidine blue and Masson,and immunohistochemical proved the expression of collagen Ⅱ.Conclusion BMSC trnsfected by hTGF-β1 could be successfully induced to chondrocyte, as the cells morphous maintained.This three dimensional condition could preferably mimicry cell growth pattern as in vivo.

Objective To investigate the feasibility of Ad-hTGF-β1 transfected bone marrow mesenchymal stem cell(BMSCs) into chondrocytes differentiation and the change of TAZ mRNA. Methods Rats BMSCs were obtained and cultured by whole bone marrow method, and then the third-generation cells were seeded into cell culture plate, and divided into three groups:Ad-hTGF-β1 transfected group,Ad-EGFP transfected group and the control group. The control group was added in common medium without any treatment while the other two groups were respectively added in serum-free medium containing Ad-hTGF-β1 or that containing Ad-EGFP. Seven days later, real-time fluorescent quantitation PCR and Western blot were employed for detecting the expression of TGF-β1 ,while immunohistochemical and Western blot for the expression of collagen Ⅱ , and real-time fluorescent quantitation PCR for the expression of TAZ mRNA. Results Seven days after the transfection, real-time fluorescent quantitation PCR revealed that the average relative expression of TGF-β1 was:Ad-hTGF-β1 group 0.863, Ad-EGFP group 0.183, and the control group 0.180; The average relative expression of TAZ was:Ad-hTGF-β1 group 0.810, Ad-EGFP group 0.416, and the control group 0.366.The expression difference of TGF-β1 and TAZ were statistically significant (P ＜ 0.05). Western blot and immunohistochemical proved strong collagen Ⅱ expression in Ad-hTGF-β1 group while it was detected a little in the other two groups. Conclusion BMSCs could be successfully and stably induced into chondrocytes differentiation by Ad-hTGF-β1. Meanwhile, the mRNA of TAZ is up regulate during the differentiation,so it is suppose that TGF-β1 improve BMSCs into chondrocytes differentiation by TAZ.

In order to investigate the strength,structure and cell cytocompatibility of injectable thermosensitive chitosan(CS)/poly(vinyl alcohol)(PVA)composite hydrogel,chitosan hydrochloride solution was transferred to a neutral pH and mixed with different proportions of PVA,then the gelation time and strength of these different hydrogels were tested and spatial structures were observed under a scanning electron microscopy(SEM)after freeze-drying.The cytocompatibility of the hydrogels was evaluated through cytotoxicity test and three-dimensional culture with bone marrow mesenchymal stem cells.The results showed that the CS/PVA solution kept in liquid state at low temperature(0-4℃)and turned into transparent elastomer about 15-20 min at 37℃.Gelation time was prolonged,the strength increased and porous structure became dense with the PVA content increased in the mixed hydrogel.The cytotoxicity grades of these gels were from 0 to 1.Rabbit bone marrow mesenchymal stem cells could survive and proliferate in the gel within 3 weeks,and the gel had good cytocompatibility,it was concluded that thermosensitive CS/PVA composite hydrogel not only has interpenetrating network structure and better mechanical strength,but also has good cytocompatibility,and may be used as an injectable scaffold for tissue engineering.

Objective: To compare the safety and efficacy of the retrograde and the antegrade techniques in laparoscopic left hemihepatectomy. Methods: Of the 65 patients who underwent laparoscopic left hemihepatectomy between January 2016 to June 2018 at the Ningbo Li Huili Hospital of Medical Center, retrograde left hemihepatectomy was carried out in 31 patients, and antegrade left hemihepatectomy in 34 patients. The perioperative data, duration of operation, intraoperative blood loss, postoperative complications (including major bleeding, abdominal abscess and bile leakage), and post-operative hospital stay were retrospectively compared between the two groups. Results: There were no significant differences in the perioperative general status between the two groups (P>0.05). Both the duration of operation [(121.5±22.1) min vs. (190.9±48.9) min, P<0.05] and the amount of blood loss [(118.9±84.1) ml vs. (195.2±85.4) ml, P<0.05] were significantly less in the retrograde than the antegrade group. There were no statistical differences in the incidences of major complications such as post-hepatectomy hemorrhage, abdominal abscess, or bile leakage, and in the postoperative hospital stay [(10.0±2.8) d vs. (12.2±3.4) d, P>0.05]. Conclusions Occlusion of hepatic vascular inflow and outflow combined with retrograde left hemihepatectomy was safe and feasibly. The retrograde approach was superior to the antegrade approach in laparoscopic left hemihepatectomy.

Imaging examinations such as CT,MRI and ultrasonography are of great importance for the diagnosis of digestive system neoplasms. However,some digestive system neoplasms are difficult to be detected at early stage and make qualitative diagnosis by conventional imaging techniques because of their unique clinical characteristics. Compared with conventional imaging techniques,endoscopic ultrasonography-guided fine needle aspiration (EUS-FNA)can not only detect the early lesions,but also make accurate qualitative diagnosis. The development and improvement of EUS-FNA greatly improve the diagnostic level of digestive system neoplasms. In this paper,the diagnostic value of EUS-FNA in digestive system neoplasms was reviewed.

Objective:To evaluate the safety and feasibility of laparoscopic radical anterograde modular pancreatosplenectomy (Lap-RAMPS).Methods:From Jan 2014 to Dec 2020, the clinical data of 83 patients who underwent laparoscopic radical resection for pancreatic tail cancer in LiHuili Hospital of Ningbo Medical Center were retrospectively analyzed.Results:Eighty-three cases were divided into Lap-RAMPS group (44 cases) and laparoscopic conventional distal pancreatectomy and splenectomy(Lap-CDP) group (39 cases). There were no significant differences in the duration of surgery [(245.34±70.30) min vs. (239.87±68.10) min], intraoperative blood lose [(159.32±115.60) ml vs. (208.97±161.70) ml] and intraoperative transfusions (2 cases vs. 3 cases) between the two groups ( P>0.05). There were no statistical significance in both groups in postoperative pancreatic fistula, postoperative bleeding grade, postoperative gastric emptying delay, Clavien-Dindo complication and postoperative hospital stay ( P>0.05). There were statistically significant differences in the negative margin rate (93.2% vs. 76.9%),lymph node harvest(12.91±8.24 vs. 8.49±6.85) and median survival time (25.0 months vs. 15.0 months) between the two groups ( P<0.05). Conclusion:Lap-RAMPS for pancreatic tail cancer is safe and feasible, increasing the negative rate of pancreatic margins, improving the lymph node harvest, and prolonging patients' survival time.