Assessment or evaluation of student performance in a problem-based learning (PBL) curriculum is difficult to plan or implement.Many medical schools which have switched to a PBL learning format usually use traditional evaluation methods based on factual recalls, which usually has a negative influence on the learning style of the students, thereby reducing the impact of PBL. The purpose of this review is to discuss the various evaluation methods with a particular focus on methods applicable to PBL, so that we can make intelligent use of these methods in our PBL curriculum. In combination with evaluation methods adopted at McMaster University, the article makes an elaboration about them.

Objective To investigate the genotype and variance of toxin associated genes of moxifloxacin‐resistant Clostridium difficile clinical isolates in Sydney .Methods Twenty‐two moxifloxacin‐resistant Clostridium difficile clinical isolates were collected from Sydney ,which were genotyped by using sequencer capillary gel electrophoresis based PCR‐ribotyping ,and toxin A and B cod‐ing gene tcdA and tcdB ,and binary toxin coding gene cdtA and cdtB were detected by using PCR method .Toxin regulator gene tc‐dC was analyzed by using PCR‐sequencing ,and was aligned with reference sequence of VPI 10463 (Genbank accession number :X92982) ,and the tcdC sequence types of all 22 isolates were identified by using blast tool in NCBI .Results Twenty‐one isolates were genotyped as hypervirulent PCR‐ribotypes 027 (RT027) ,and one isolate as RT078 ;all 22 isolates contained tcdA and tcdB for toxin A and B and cdtA and cdtB for binary toxin (tcdA+ tcdB+ cdtA+ cdtB+ ) .The tcdC sequence types of the 21 RT027 i‐solates belong to sc1 ,and that of the one RT078 isolate belongs to WA39 .Compared with tcdC reference sequence of VPI 10463 ,a consecutive 18 bp deletion (nt341 to 379) and one nucleotide deletion at position 117 were found in the 21 RT027 isolates ,and a consecutive 39 bp deletion (nt330 to 368) and one nucleotide mutation at position 184(C> T) were found in the one RT078 isolate . Conclusion Clostridium difficile hypervirulent RT027 was the common moxifloxacin resistant genotype ;Clostridium difficile hy‐pervirulent RT027 and RT078 clinical isolates contained genes for toxin A and B and binary toxin ,and contained gene sequence mu‐tation in toxin regulator gene tcdC .

Objective To investigate the genotype and production of toxin A and B of C .difficile clinical isolates collected from Sydney ,Australia .Methods Sixty‐eight C .difficile clinical isolates were collected from Westmead Hospital ,the University of Sydney ,which were genotyped by using PCR‐ribotyping ,and toxin A ,B coding gene tcdA ,tcdB were detected by using PCR meth‐od .Results Thirty‐one PCR‐ribotypes (RTs) were confirmed in the 68 C .difficile clinical isolates ,RT014 (19 .1% ) and RT002 (11 .8% ) were the common genotypes .Sixty‐four of 68 (94 .1% ) isolates contained tcdA and tcdB for toxin A and B .Conclusion The common prevalent PCR‐ribotypes of C .difficile were RT014 and RT002 in Sydney ,most of the C .difficile clinical isolates contained toxin A and B .

BACKGROUND:Tissue-engineered bone scaffold fabricated by 3D-bioprinting technique has good controlability in morphology and structure. However, construction of tissue-engineered bone/cel growth factor complex and time-dose effect of sustained-release factors are needed to be further researched.
OBJECTIVE:To fabricate a sustained-release composite of polylactic-co-glycolic acid (PLGA)/nano-hydroxyapatite (n-HA) scaffold carrying bone morphogenetic protein-2 (BMP-2) using 3D-bioprinting technique, and test the biological properties of the PLGA/n-HA scaffold carrying BMP-2 and the sustained-release properties, thereby to discuss its feasibility as the tissue-engineered bone scaffold composite.
METHODS:Temperature-sensitive chitosan hydrogel was prepared using chitosan andβ-glycerophosphate to construct a sustained-release composite, chitosan nanoparticles carrying BMP-2 . 3D-bioprinting technique was utilized to fabricate the PLGA/n-HA scaffold carrying BMP-2. Biological features of the scaffold composite were tested, and time-dose effect of BMP-2 sustained-release was observed.
RESULTS AND CONCLUSION:The average pore size of the scaffold-cytokine composite was (431.31±18.40)μm, and the porosity was (73.64±1.82)%. The cumulative release rate of BMP-2 from the scaffold-cytokine composite that effectively controled the burst release during 48 hours and 30 days were suitable for the physiological needs. In conclusion, the porosity, pore size, release property, degradation rate, and mechanical strength of the scaffold-cytokine composite al meet the biological requirements of tissue-engineered bone construction.

Objective To study the correlation between microRNA (miRNA) polymorphism and the risk and clinical prognosis of acute radiation esophagitis in patients with esophageal neoplasms. Methods 256 patients with acute radiation esophagitis during radiotherapy were chosen as the experimental group, and 256 patients matched by age and sex without acute radiation esophagitis during radiotherapy were chosen as the control group. The polymorphism types of miRNA-146a (rs2910164) were determined by Taqman gene typing technology of ABI7900HT. The genotype distribution of miRNA-146a rs2910164 polymorphism in the experimental and control groups was analyzed. Logistic regression was performed to estimate the odds ratio (OR) and 95%confidence interval (95%CI ). Results The genotype frequencies of CC, GG and CG at miRNA-146a polymorphic site rs2910164 in the experiment and control group were 20.70 % (53/256) and 33.20 % (85/256), 45.32 % (116/256) and 40.63 % (104/256), 33.98 % (87/256) and 26.17 % (67/256), respectively. There was a statistically significant difference between two groups (all P< 0.05). Compared with gene type CC, the OR values of acute radiation esophagitis in patients with gene type GC and GG were 0.654 and 0.627, respectively (P< 0.05), indicating that they had a low risk. The negative effect rates in patients with gene type GG, CG and CC were 7.69 % (8/104), 19.40 % (13/67) and 41.18 % (35/85), respectively. There was a statistically significant difference in the clinical prognosis among these genotypes (P< 0.05). Conclusion Gene type CC at miRNA-146a polymorphic site rs2910164 can increase the risk of acute radiation esophagitis and decrease the clinical prognosis in patients with esophageal neoplasms.

ObjectiveTo investigate the managements of complications during and after peroral endoscopic myotomy (POEM) for esophageal achalasia (EA).MethodsData of 119 EA patients who underwent POEM from October 2010 to July 2011 were collected.Complications during and after POEM and during follow-up were analyzed.Results Complications during operation included bleeding in 19 patients ( 16.0％ ),mucosa rupture in 9 (7.6％),mediastinal and subcutaneous emphysema in 27 (22.7％ ) and pneumothorax in 3 (2.5％ ).Complications occurred at the night of procedure included pain in 43 (36.1％ ) patients and pneumothorax in 7 ( 5.9％ ).Postoperative complications included asymptomatic pneumothorax in 23 patients (19.3％),delayed hemorrhage in 1(0.8％),pleural effusion in 58 (48.7％ ),minor pulmonary inflammation or segmental atelectasis in 59 (49.6％),emphysema of mediasti-na and subcutaneous tissue in 76 (63.9％ ),and gas under diaphragm or aeroperitoneum in 47 (39.5％ ).Complications during follow-up included one case of dysphagia caused by stricture of mucosa and one case of dehiscence at the tunnel entry with food retention.No POEM-correlated death occurred.All the complications were cured by conservative treatments.No additional surgery was needed.ConclusionMain complications as emphysema of mediastina and subcutaneous tissue,pneumothorax,aeroperitoneum and bleeding during and after POEM can be treated timely and effectively with conservative treatment.

Objective To investigate the effect of sperm preparation in male infertility on sperm morphology and DNA fragmentation index(DFI). Methods Four hundred men were divided into the groups of fertile , teratozoospermics and unexplained subfertility. Sperm morphology and DFI were analyzed before and after the sperm preparation. Results Sperm abnormal morphology and DFI in the infertility group were higher than those in the fertile group ,but significantly decreased after sperm preparation. The method of density gradient separation results in obtaining better sperm(P<0.01). Conclusions Compared to the method of swimming up ,the method of density gradient separation could result in obtaining sperm with improved normal morphology and DNA integrity.

Objective: To investigate influences of different rehabilitative methods on function of hands and psychological anxiety of patients with deeply burned hands retaining denatured dermis and grafting large autologous skin. Methods: Forty-four patients with deeply burned hands, conforming to the study criteria were admitted to Department of Burns and Reconstructive Surgery of Xiangya Hospital of Central South University from January 2014 to June 2015. Patients were divided into propaganda education rehabilitation group (PER, n=23) and specially-assigned person rehabilitation group (SAPR, n=21) according to the random number table and patients′ willingness. On post injury day 3 to 7, 36 burned hands in group PER and 33 burned hands in group SAPR underwent operation of retaining denatured dermis and grafting large autologous skin. Patients in 2 groups received anti-scar treatment of hands with silicone gel from postoperative day 10. Besides, patients in group PER underwent active functional exercise under guidance of duty nurse and received psychological guidance from duty nurse with grade two psychological consultant certificate. Patients in group SAPR underwent active and passive functional exercise under guidance of rehabilitation therapist and received psychological guidance from psychotherapist with intermediate title. In postoperative month (POM) 1, 3 and 6, ranges of active motion of burned finger joints of patients in 2 groups were measured with joint goniometer to calculate excellent and good ratio of total active motion (TAM) range. Values of grip strength of burned hands of patients were measured with electronic hand dynamometer, and psychological anxiety was scored with Self-rating Anxiety Scale (SAS). Data were processed with chi-square test, independent sample t test, McNemar test, analysis of variance of repeated measurement, SNK test and Bonferroni correction. Results: (1) Ratio of excellent and good of TAM range of burned finger joints of patients in group SAPR in POM 6 was obviously higher than that in group PER (χ²=10.745, P<0.0167 ). Ratio of excellent and good of TAM range of burned finger joints of patients in 2 groups in POM 3 were obviously higher than that in POM 1 of the same group, respectively (with P values below 0.0167). (2) Values of grip strength of burned hands of patients in group SAPR in POM 1, 3, and 6 were respectively (8.2±2.6), (21.6±2.6) and (30.1±2.3) kg, obviously higher than those in group PER [ (5.3±1.3), (12.8±2.7), (20.0±1.8) kg, respectively, with t values from 5.934 to 20.403, P values below 0.01]. Values of grip strength of burned hands of patients in 2 groups in POM 3 and 6 were obviously higher than those at the previous time point of the same group (with P values below 0.05). (3) SAS scores of patients in group SAPR in POM 1, 3 and 6 were significantly lower than those in group PER (with t values from 2.944 to 4.758, P values below 0.01). SAS scores of patients in 2 groups in POM 3 and 6 were significantly lower than those at the previous time point of the same group (with P values below 0.05). Conclusions Compared with rehabilitation of propaganda and education, rehabilitation under specially-assigned person can improve TAM range of burned finger joints, value of grip strength, and psychological anxiety of patients with deeply burned hands retaining the denatured dermis and grafting large autologous skin.

Objective To evaluate the efficacy and safety of endoscopic submucosal dissection (ESD) in the treatment of giant gastrointestinal lipomas.Methods From August 2007 to August 2010,the clinical data of 32 patients with giant gastrointestinal lipomas treated by ESD at Endoscopy Center,Zhongshan Hospital Fudan University were retrospectively analyzed.Among 32 cases of giant gastrointestinal lipomas,one case was in esophagus,six cases in stomach,two cases in duodenum,seven cases in ileocecal valve,15 cases in colon and one case in rectum. Preoperative diagnostic accuracy of endoscopic uhrasonography (EUS) was 93.8％ (30/32).The maximum diameter of tumor ranged from 3.0 cm to 8.0 cm (average 4.2 cm).Results All tumors were successfully dissected under endoscopy.The success rate was 100％ (32/32).The operation time was between 25 minutes and 110 minutes (average 37 minutes).The average intraoperative blood loss was 40 ml,and no perforation and delayed bleeding was found after ESD. All were proved to be lipomas by histopaphology after operation.The rate of follow-up was 90.6％ (29/32).The follow-up time was from six to 36 months.Conclusion ESD is a safe and effective method for the treatment of giant gastrointestinal lipomas,which can be applied extensively in clinical.

Objective To explore the clinical value of endoscopic ultrasonography (EUS) examination before esophageal achalasia (EA) patients treated by peroral endoscopic myotomy (POEM).Methods From August 2011 to November 2011,esophageal EUS examination was conducted in 34 EA patients scheduled for POEM treatment (EA group) and 30 cases accepted gastric EUS examination (control group) at endoscopic center,Zhongshan Hospital,Fudan University.The thickness of muscularis propria layer and the circular muscle layer was measured at cardia,5 cm,10 cm and 15 cm above cardia,and the proportion of circular muscle layer was calculated.The differences in groups and between groups were compared.The correlation between muscle thickness and complication after POEM treatment was analyzed.The data were analyzed by t test.Results There was no difference between EA group and control group in the thickness of the muscularis propria layer at same part (at cardia,5 cm,10 cm and 15 cm above cardia,t=1.210,1.116,0 and 0.292respectively; all P＞0.05 respectively).The thickness of the circular muscle layer of EA group at cardia,5 cm,10 cm and 15 cm above cardia was (1.72±0.49) mm,(1.86±0.81) mm,(1.56±0.47) mm and (1.41±0.48) mm respectively,those of control group was (1.06±0.50) mm,(1.40±0.33) mm,(1.05±0.37) mm and (0.78±0.12) mm respectively.At same part,the thickness of the circular muscle layer of EA group was significantly thicker than that of the control group (t =5.326,2.903,4.778 and 6.993 respectively,all P＜0.05).After POEM treatment,complication was high in EA cases with the thickness of muscularis propria layer less than 2 mm.Conclusion Before POEM treatment,EUS examination for EA patients has certain guiding significance.