Objective To investigate the modulation role of autophagy in radiation-induced cell death by detecting the response of src kinase activity and autophagy in HEK293 cells irradiated with different dose of α-particle.Methods HEK293 cells were irradiated by contral group (0 cGy) a low dose group (10 cGy) and high dose group (300 cGy) α-particles.Molecular probe 2',7'-dichlorofluorescin (DCFHDA) was used to detect the cell ROS.The src kinase activity and endogenous protein level of LC3Ⅰ/Ⅱ were monitored by Western Blot.Cell death rate of irradiated cells pretreated with autophagy inducer of rapamycin was tested by flow cytometry.Results Compared with control group,the ratio of LC3Ⅰ/Ⅱ decreased (t =4.07,P ＜ 0.05) and the percentage of cells with GFP-LC3 punctuate dots increased (t =12.29,P ＜0.05) under 10 cGy irradiation,indicating the induction of autophagy.On the contrary,the ratio of LC3Ⅰ/Ⅱ increased (t =2.93,P ＜ 0.05) and the GFP-LC3 morphology had no obvious change under 300 cGy irradiation.The cellular ROS level reached to the maximum value at 4 h postirradiation.Both 10 cGy and 300 cGy irradiation could elevate the ROS level (t =17.93,22.88,P ＜0.05),whereas the amplitude of elevation of 300 cGy irradiation was higher than that of 10 cGy irradiation (t =15.76,22.66,14.22,P ＜ 0.05).Compared with control group,the 419th site of tyrosine residue in src kinase manifested hyper-phosphorylation (t =5.66,P ＜0.05) under 10 cGy irradiation whereas it had hypo-phosphorylation under 300 cGy irradiation (t =4.67,P ＜ 0.05).Treatment of cells with DMSO could partly restore the impact on src kinase activity under high or low dose irradiation.Pre-treating the cells with autophagy inducer rapamycin could reduce cell death under 300 cGy irradiations (t =12.14,P ＜ 0.05).Conclusions High or low dose of α-particles irradiation could inhibit or activate src kinase and autophagy system,respectively.ROS mediated the response of src kinase activity and autophagy system induced by irradiation.Modulation of autophagy could desensitize cell responses to irradiation.

Objective To investigate the expressions and the clinical significance of nectin-4 in pancreatic carcinoma and the relationship with clinicopathological features. Methods Immunohistocbemical techniques were used to detect nectin-4 expression in pancreatic carcinoma tissues (n = 40) and normal pancreatic tissues (n = 12 ), and the relationship between the expressions and clinicopathological parameters was analyzed. Results The IOD and area of nectin-4 were 2. 43 ± 0.75 and 9. 73 ± 1.86 in pancreatic carcinoma tissues, which were significantly higher than those in the normal pancreatic tissues( P ＜ 0.01 ).The expression of nectin-4 was not correlated with patients demographics ( P ＞ 0.05 ), and the protein expression was correlated with histopathologic grade ( P ＜ 0.01 ) and lymph metastasis ( P ＜ 0.05 ).Conclusions The high expression of nectin-4 in pancreatic carcinoma tissues suggests that its high expression may be correlated with the malignant degree of the carcinoma. nectin-4 can be considered as a reference index of differentiation, metastasis and prognosis in pancreatic carcinoma.

Objective To investigate the potential of pancreatic stem cells (PSCs) directed differentiation in vitro, and to evaluate the effects of differentiated PSCs allograft on the treatment of diabetes.Methods The PSCs of adult Wistar rats were separated and purified in vitro. The surface of PSCs was determined by immunofluorescence staining, and then it was stimulated by hepatocyte growth factor (HGF) and nicotinamide to induce directed differentiation. Dithizone dyeing was used to determine the islet-like cells after induction, and ELISA staining method was used to detect the insulin levels. Streptozotocin peritoneal injection was used to induce the diabetic rat mode. 40 rats were randomly allocated into pancreatic islet cells allograft group (experiment group) and placebo group. The serum insulin and glucose levels 1 d before transplantation and 1, 2, 3, 4 week after transplantation were measured. Results PSCs of adult Wistar rats were successfully obtained, and the expression of CK19, Pdx-1 and Nestin on cell surface was positive. Dithizone dyeing for directed differentiation cells showed brownish red color. The cells could express and secrete insulin after hyperglycaemia stimulation. The serum insulin and glucose levels 4 week after transplantation were (11.41 ±1.52) mU/L and (8.22 ± 2.7) mmol/L, which were (9.30 ± 1.56) mU/L and (12.23 ± 3.8) mmol/L in the placebo group, and difference was statistically significant (P＜0.05). Conclusions PSCs can be induced and directed differentiated in vitro into islet-like clusters with insulin secretion function. And its allograft has the potential for the treatment of diabetes.

BACKGROUND: Transforming growth factor-β(TGF-β) is an essential factor for pathological scar formation. Smad protein group is the signal protein of lower reaches of TGF-β receptor. Asiaticoside can inhibit proliferation of fibroblasts and synthesis of collagen to reduce TGF-β expression in the scar.OBJECTIVE: To study the mechanism of asiaticoside on proliferation of scar fibroblasts and phosphorylated Smad2 and Smad7.DESIGN: Controlled study with observation, in which cell was taken as the object.SETTING: Department of burn and plastic surgery of a hospital affiliated to a university.PARTICIPANTS: The experiment was performed in Surgical Laboratory in Sun Yat-sen University from April 2002 to March 2003. The specimens were selected from 6 inpatients receiving plastic operation due to hyperplasic scar including 3 male and 3 female cases aged varied from 1 to 35 years. The hyperplasic scar fibroblasts were obtained generated from original culture in laboratory of surgical department.INTERVENTIONS: In the research, the experiment group and the control group were divided. In the experiment group, asiaticoside was applied on fibroblasts; in the control group, asiaticoside was not prescribed. The changes of every index were observed before and after medication.MAIN OUTCOME MEASURES: ① Effect of asiaticoside on expression of phosphorylated Smad2 and Smad7; ② Effect of asiaticoside on cell cycle and apoptosis.RESULTS: Asiaticoside inhibited scar fibroblasts entering M phrase from S phrase and reduced the content of phosphorylated Smad2 in fibroblasts, which did not present significant difference in two groups ( t = 1.53, P =0.08).The content of Smad7 in the cells was (50. 80 ± 22.40)% in the experiment group and (32.18 ± 17.84)% in the control group, which indicated significant difference ( t = 2. 17, P = 0. 024).CONCLUSION: Asiaticoside inhibits scar formation by Smad passage.

ObjectiveTo explore the role of vascular endothelial growth factor(VEGF) in the growth and development of hypertrophic scar.MethodsThe burn wound samples of various stages were selected from transition of wound granulation tissue to scar and in long-persisting post-burn hypertrophic scar, and the concentrations of VEGF protein were detected using enzyme-linked immunosorbent essay (ELISA) method. ResultsThe tissue homogenate concentration of VEGF protein increases gradually from the wound granulation tissue to hypertrophic scar before it achieves summit concentration during 4 to 6 month. The concentration of VEGF degreases gradually after the maturation of hypertrophic scar. The high concentration of VEGF is synonymous with the large amount of capillary of the immature scar.ConclusionsThe abnormal expression of VEGF is related to the growth and development of hypertrophic scar and induces excessive and uncontrollable angiogenesis.

OBJECTIVETo investigate the bacterial epidemiology in our department in recent years, so as to provide assistance to the clinical management of burn patients.

METHODSA retrospective analysis was carried out with 345 bacterial cultures from burn wound and drug-sensitivity results in 784 burn patients during 1993 to 1999 in our department.

RESULTS(1) Among all the bacteria, gram negative (G(-)) bacilli accounted for 56.8%, while gram positive (G(+)) cocci and fungi in 3.8%. (2) Among all the G(+) cocci, 65.4% were Staphylococcus aureus, in which MRSA was identified in 53.9% during 1993 - 1999 and in 64.3% during 1998 - 1999. Pseudomonus aeruginosa accounted for 37.2% of all G(-) bacilli. (3) The 3rd generation of cephalosporins shew excellent anti-bacterial capabilities, but the bacterial resistance to them increased significantly. (4) MRSA was very sensitive to both vancomycin and norvancomycin with no report of antibiotic resistance to them.

CONCLUSIONG(-) bacilli were still predominant bacteria in our burn department when compared to G(+) cocci. The 3rd generation cephalosporins are the routine antibiotics for the present. But resistant bacteria are on the increase. There are also more and more MRSAs isolated from burn wounds. For this, vancomycin and norvancomycin should be preferably used.

Adolescent ; Adult ; Aged ; Aged, 80 and over ; Anti-Bacterial Agents ; pharmacology ; Burns ; microbiology ; Female ; Humans ; Male ; Microbial Sensitivity Tests ; Middle Aged ; Pseudomonas aeruginosa ; drug effects ; Retrospective Studies ; Staphylococcus aureus ; drug effects