BACKGROUND: Simply used natural materials-prepared scaffolds such as collagen, gelatin and fibrin solve problems of biocompatibility, but its degradation is rapid, and cannot induce new tissues, but collapse is found as cell scaffolds.OBJECTIVE: To explore and determine the property of biological degradable three-dimensional porous scaffolds using silk fibroin-chitosan composite.DESIGN, TIME AND SETTING: The material observational study was performed at the Institute of Bioengineering, Zhejiang Academy of Medical Science from June 2008 to June 2009.MATERIALS: Spring silk cocoon was presented by a silkworm farmer from Huangdunmiao village, Maqiao town, Haining City,Zhejiang Province, China. Chitosan was produced by Shanghai Bo'ao Biological Technology.METHODS: 15 g/L silk fibroin solution was made by degumming, salvation and dialysis. Chitosan was dissolved in 2% acetic acid solution to prepare 25 g/L chitosan-acetic acid solution. Two solutions were mixed to prepare six silk fibroin/chitosan solutions, and mass ratio was 10: 0, 5: 5, 4: 6, 3: 7, 2: 8, 0:10. These solutions were separately sucked in a 24-well plate. Following exhausting gas vacuole at 4 ℃, precooling was performed at -20 ℃ for 12 hours, followed by cryodesiccate for 30 hours. Samples were then hydrated in ethanol, neutralized in NaOH-alcohol for 1 hour, washed and then frozen to dry.MAIN OUTCOME MEASURES: Optical microscope and scanning electron microscope were used to observe pore size and structure of various mass ratio-prepared scaffold. Modified liquid substitution method was utilized to measure porosity of various scaffolds. The degradable rate of various scaffolds was determined at 4 weeks in vitro.RESULTS: Silk fibroin/chitosan of 10: 0 mass ratio-prepared scaffold had rough fluffy pore, was brittle, with high dissolve-loss rates. On the contrary, chitosan-prepared scaffold was hard, without enough elasticity following freeze-dry. The composite scaffold of 5: 5, 4: 6, 3: 7 and 2: 8 following freeze-dry was loose and soft, similar to sponge. With increased chitosan concentration,scaffold hardness increased. There were evenly distributed, detailed eyelets on the scaffold. Under the optical microscope,various pores were irregular; each pore closely connected and linked together; pore size was even, 20-100 μm. With increased chitosan concentration, pore size was gradually reduced. Scaffold porosity determination results displayed that mass ratio of silk fibroin/chitosan 4: 6 group > 5: 5 group > 3: 7 group > 2: 8 group. Compared with 2: 8 group, the porosity was significantly increased in the 5: 5 and 4: 6 groups (P < 0.05). No significant difference was detected in volume expansibility in the silk fibroin/chitosan composite scaffold of various mass ratios (P > 0.05). The degradation was slowest in the 2: 8 group, and fastest in the 5: 5 group at 4 weeks.CONCLUSION: Regarding physical and chemical properties, composite scaffold made by silk fibroin/chitosan showed significant superiority compared with scaffold made by silk fibroin or chitosan alone. Of them, silk fibroin/chitosan mass ratio of 5: 5 and 4: 6 are accorded with the requirement of cartilage tissue engineering.

OBJECTIVE: To prepare chitosan microspheres encapsulated transforming growth factor β1 (TGFβ1), and to analyze its property. METHODS: The chitosan was dissolved in 2% acetic acid to prepare chitosan microspheres encapsulated TGFβ1 with emulsification cross-linking method, Tween 80 and sodium polyphosphate were served as emulsifying agent and cross-linking agent, respectively. Meanwhile, chitosan microspheres and containing bovine serum albumin chitosan microspheres were prepared as blank control and experimental control groups. The morphology and diameter of 3 kinds of microspheres were observed, and the dispersion and in vitro release of chitosan microspheres encapsulated TGFβ1 were detected, furthermore, the water absorption expansion rate of blank control and experimental control groups were measured. RESULTS: Scanning electron microscopy showed that the microspheres diameter in the blank group was approach 15 μm, with smooth surface and plenty of tiny pores. However, the microspheres in the other 2 groups were distributed uniformly with approximately 1 μm in diameter, the surface was smooth. The chitosan microspheres encapsulated TGFβ1 released fast at begin 12 hours, and then gentled gradually, with 53.5% release ratio within 6 days. The increased mass of microspheres in the blank control and experimental control groups reached a balance after 1 hour, both of which were over 700%,in particular larger in the acid environment. CONCLUSION: Chitosan microspheres encapsulated TGFβ1 prepared by emulsification cross-linking method exhibit high yield and good drug release. The strong water absorption expansion rate of chitosan microspheres requires aperture size, as well as intensity of bone tissue engineered scaffold.

[Objective]To evaluate the effectiveness of recombinant human bone morphogenetic protein-2 in the repair of rabbit rotator cuff injury.[Method]Forty-eight male New Zealand rabbits,aged 8 months,received an rotator cuff acute injury and reconstruction of the insertion of supraspinatus tendon on greater tuberosity of humerus.The rabbits were randomly divided into 3 groups postoperatively:(1) rhBMP-2 group:fibrin sealant(FS) containing rhBMP-2 was applied to the interface between the bone-tendon interface; (2)FS control group:only FS was applied;(3)blank control group:untreated after the surgery.Harvested 36 specimens underwent biomechanical analysis at the 2nd,4th,8th postoperative weeks respectively.Harvested 12 specimens underwent histological analysis at the 8th postoperative week.[Result]Histological examination showed that Sharpey's fibers were found in the interface with the formation of four-layer indirect insertion in the rhBMP-2 group at the 8th postoperative week.In the FS control group and blank group,the tendon-bone interface was filled with granulation tissue and part of Sharpey's fibers and the newly generated bone tissue.Biomechanical analysis displayed that the tensile strength and stiffness of bone-tendon interface increased time-dependently in all groups,and it in the rhBMP-2 group was significantly higher than those in the other two groups at any time-points (both P

Objective To investigate the value of 18F-FDG PET/CT and serum CEA in patients with advanced gastric cancer after neoadjuvant chemotherapy combined with surgical treatment.Methods 96 cases of patients with advanced gastric cancer who underwent neoadjuvant chemotherapy combined with surgery as the research object,after more than 2 years of follow-up,PET/CT imaging and serum CEA levels were detected,and the diagnostic value of recurrence or metastasis of the two groups were evaluated and analyzed.Results Of the 96 patients enrolled in the study,there were 47 cases of recurrence and metastasis,PET/CT combined with CEA for recurrence or metastasis positive diagnosis rate and negative diagnosis rate was significantly higher than that of pure PET/CT and serum CEA,the difference was statistically significant(P<0.05).The sensitivity,specificity and accuracy of PET/CT combined with CEA in the diagnosis of recurrence or metastasis were higher than that of PET/CT and serum CEA,the difference was statistically significant(P<0.05).Conclusion The combined monitoring of 18F-FDG PET/CT imaging and serum CEA level in patients with advanced gastric cancer after neoadjuvant chemotherapy combined with surgical treatment is helpful to improve the diagnosis of metastasis or recurrence.

Objective To evaluate a minimally invasive procedure for intertrochanteric fracture treatment in elderly patients. Methods Total 46 elderly patients with intertrochanteric fracture were treated with a minimally invasive procedure from September 2008 to February 2010. The fractures were fixed with multiple K-wires combined with skeletal traction through supracondyle of femur. All procedures were undertaken under local anesthesia. Results All the patients were followed up for 8.8-months in average, and 42 patients recovered with independent walking, and the good rates was 91.3%, without severe complications in this group. Conclusions Minimally invasive procedure including fixation with multiple K-wires combined with traction through femoral supracondyle, is a safe and effective treatment for intertrochanteric fracture in elderly patients, avoiding high risks of intra-and post-operative complications.

Rheumatoid arthritis (RA) is a systemic autoimmune disease with unknown etiology.The main feature of RA is chronic,symmetrical and invasive arthritis.RA may present with severe joint deformity and functional loss,which has higher disability and fatality rates.At present,no effective measures can reverse bone damage associated with RA clinically.Therefore,early diagnosis of RA is critical to improve prognosis.In recent years,imaging increasingly plays an important role in the early diagnosis of RA.This article reviews recent advances in imaging methods for early diagnosis of RA.

Objective In a large-scale clinical medical examination, A2 type best multiple-choice test questions to the same knowledge were used respectively in simple and complex form, to compare the difficulty and discrimination indices of the two forms of test questions and provide evidence to the improve-ment of clinical medical examination. Method In a large-scale clinical medical examination more than 4000 candidates participated, and 20 questions to different knowledge points were randomly selected and used in the examination respectively in simple and complex A2 type best multiple-choice test questions. The difficulty and discrimination indices of the two forms of test questions were compared. Results The average difficulty coefficient of the 20 simple test questions (65.5 words per question in average) is 0.6829, and the average discriminative powers are 0.2675 and 0.2579 respectively using identification index method and point biserial correlation method. The average difficulty coefficient of the 20 complex test ques-tions (135.5 words per question in average) is 0.7095, and the average discriminative powers are 0.3065 and 0.2967 respectively using identification index method and point biserial correlation method. Conclusion To the same knowledge points, the average difficulty of complex A2 type best multiple-choice test questions is slightly lower than the simple ones, while the average discriminative power is increased in the complex questions. The complex A2 type test questions are of higher quality and more in line with the requirements of the medical entrance examination, medical education and examination reform.

Objective To investigate the diagnostic and prognostic value of neutrophil-to-lymphocyte rate ( NLR) in acute pancreatitis related acute kidney injury patients .Methods Peripheral blood specimens and clinical information of 98 acute pancreatitis patients in Wenzhou Center Hospital were collected .The WBC, neutrophils , lymphocytes were detected and NLR were calculated when they were admitted .The patients were divided into two groups by their NLR and whether they were with AKI respectively .Besides, ALT, Hct, TC, TG, blood calcium concentration , serum creatine and urea nitrogen , C reactive protein were detected and patients′APACHEⅡ score were also recorded to analyze the difference between the two groups .Results There is no significance in the age , BMI, Hct, TG, TC, ALT and blood calcium between AP patients with and without AKI.The blood creatinine, BUN, CRP, APACHEⅡscore were (395 ±122)μmol/L, (28.2 ±5.2) mmol/L, (34.0 ±8.2)mg/L, (11.5 ±3.8) score, respectively in AP patients with AKI, and which were (79 ±17 )μmol/L, ( 7.3 ±2.0 ) mmol/L, ( 14.8 ±2.9 ) mg/L, ( 6.9 ±2.4 ) score, respectively in AP patients without AKI.The blood ALT, blood creatinine, BUN, CRP, APACHEⅡscore were (257 ±76)U/L, (159 ±62)μmol/L, (20.5 ±6.6)mmol/L, (24.8 ±5.5)mg/L and (12.4 ±4.6) score in the patients with higher NLR respectively , and which were ( 165 ±30 ) U/L, ( 98 ±23 )μmol/L, ( 14.3 ±5.2 ) mmol/L, (19.5 ±3.0)mg/L and (5.4 ±2.1) score in the patients with lower NLR respectively .NLR was 4.97 ±0.19 in AP patients with AKI, and was 9.62 ±0.81 in AP patients without AKI.The difference between the two groups was significant(P=0.0001).The area under ROC curve of diagnosing AP by NLR was 0.895 (95%CI 5.75).the sensitivity was 89.5%and the specificity was 77.2% when using 5.75 as the cut-off value to diagnose AP related AKI with NLR .Conclusions NLR can be a potential predictive index of the severity and relate to renal function in acute pancreatitis related acute kidney injury patients .

Objective To compare the efficacy of the radical resection by laparoscopy versus open approach in perioperative period on the patients with rectal carcinoma,and investigate the feasibility,safety and oncological clearance of the laparoscopy.Methods The clinical data of 44 patients who underwent radical resection of rectal carcinoma by laparoscopy in our hospital were reviewed and compared with another 53patients who underwent an open approach in the same period.The surgery-related data,postoperative recovery status,tumor radical resection index,and postoperative complications by laparoscopy were analyzed by statistics,and compared with those by open approach,and evaluated the deference of too kinds of operation.Results This study showed a longer surgical time (260.45 ± 67.46) min vs ( 179.25 ± 40.92) min,P ＜0.05,a less intra-operative blood loss( 125.20 ±61.80) mL vs ( 198.02 ± 131.24) mL,P ＜0.05,in laparoscopic group compared with open approach.Meanwhile,it also showed an earlier recovery of bowel functions for discharge gas from anus,taking in food,and out-of-bed activity (4.34 ± 1.55) d vs(5.45 ± 1.55) d,P ＜0.05,in the laparoscopic group compared with open approach.There was no statistical difference of incidence of post-operative complications (5 cases vs 11 cases,P ＞0.05) between the two groups and the laparoscopic approach was also equal to the open approach as regard to post-operative stay (15.34 ±6.62) d vs (16.82±5.73) d,P ＞0.05,and demand of intra-operative blood transfusion (4 case vs 8 cases,P＞0.05 ).Conclusions Compared with open surgery,the radical resection of rectal carcinoma by laparoscopy has shown obvious advantages in smaller incision,less blood loss,less pain,earlier recovery of bowel and bladder functions,and earlier out-of-bed activity.And it is also possible by laparoscopy approach to decrease the post-operative complications and post-operative stay.Meanwhile,there is no significant deference on oncological clearance for laparoscopy compared with open approach during perioperative period,while the long term follow-up data is still needed to support the results.

BACKGROUND:Continuing stress stimulation has been confirmed to promote repair of rotator cuff injury.This experiment attempts to fu rther quantify the intensity of stress stimulation in order to reach a better therapeutic effect in the entire process of rotator cuff injury repair.OBJECTIVE:To explore the biomechanical performance of stress stimulation with different intensities on repair of acute rotator cuffinjuryMETHODS:Sixteen male New Zealand rabbits were randomly divided into high intensity,low intensity and control groups,with 12 animals in each group.Rabbits were received a rotator cuff acute injury and reconstructing insertion of supraspinatus tendon on greater tuberosity of humerus.At 1 week after operation,rabbits were treated by continuous passive motion(CPM)apparatus,which was-60°to 60° flexion-extension for the high intensity group,and-15° to 15° for the low intensity group.At 2 weeks after operation,the CPM was performed every other day,with 10 minutes per time;which was changed to daily training from week 3 with the same frequently,and 15 minutes per time at week 4.Rabbits in the control group were housed freely.Each 4 animals were sacrificed at weeks 2,3 and 4 after operation,and the largest tensile strength and severity at osteotendinous junction were compared.RESULTS AND CONCLUSION:The maximum tensile intensity and stiffness of the supraspinatus tendon in the low intensity group were greater than that of the control and high intensity group(P＜0.05),which was smallest in the high intensity group.All the breakage point existed at the intra-articular portion.The result demonstrated that low intensity stimulation exhibits superior repair effect in acute rotator cuff injury,while high intensity stimulation is harmful to the early repair of acute rotator cuff injury.