Objective To evaluate the application effect of the problem based learning in clinical teaching of orthopedics. Methods We chose sixty five-year program students of Peking univ-ersity health science center as research object. All students were randomly divided into experimental and control groups, with thirty students in each group. Experimental group was given PBL teaching combined with lecture based learning (section-based learning, LBL), while the control group only received the LBL teaching. Two groups were given 8 hours of teaching experiments. After the end of the study, the teaching effect of the two groups was evaluated by the theory course and clinical skills. The questionnaire was distributed to the 2 groups. The scores of both experimental group students and control group students in theory courses and clinical skills were analyzed using SPSS 19.0 software using t-test and x2 test. Result The score of the experimental group was (53.7 ±3.2) in the knowl-edge-based grades exam, while the control group was (52.3±2.2), showing no obvious difference when compared to the control group's grades (P>0.05). The score of the experimental group was (24.0±1.5) in the hands-on technique grades exam, while the control group was (22.3±1.6). The difference in grades showed statistical significance (P<0.05). Feedback survey results showed that the experimental group's teaching satisfaction degree was also significantly higher than the control group, and the dif-ference was statistically significant (P<0.05). Conclusions The application of PBL in clinical teach-ing in orthopedic clinical teaching can improve students' learning interest and self-study ability, and helps to develop students' clinical thinking ability. But the role of PBL teaching in improving students' medical knowledge level is not obvious.

Through developing resident standardization training,we established programs of resident standardization training,defined training aims,standardized training items,and established guarantee system,evaluation system,quality-monitoring system and encouragement system,which guaranteed the quality of residency training,and acquired satisfactory effects.

Through approaching the mixed ability training of clinical post-graduates, the following conclusions were drawn: necessity to take turns in the clinical specialties, establishment of its program, the details and contents were pointed out, meanwhile, it is necessary to guarantee progression of the plan and its training effects, and to improve the cultivation quality.

Objective To study the inhibitory effects of Probucol on the expressions of serum promatrix metalloproteinase-2(pro-MMP-2) and matrix metalloproteinase-2(MMP-2) in patients with coronary heart disease(CHD).Methods The levels of serum Pro-MMP-2 and MMP-2 were detected by zymograph and total cholesterol(TC),triglyceride(TG),high density lipoprotein cholesterol(HDL-C),low density lipoprotein cholesterol(LDL-C)were measured by enzyme method in 30 CHD patients before and after treatment with Probucol.Results After treatment of Probucol,the expression levels of pro-MMP-2,MMP-2,TC and LDL-C in serum were decreased than those before treatment,respectively;there were obvious differences of various indexes mentioned above between before and after treatment(P0.05).Conclusion Probucol can inhibit the expressions of pro-MMP-2 and MMP-2 in serum as same as TC and LDL-C.Probucol,as one of TIMPs,may be applied to stabilize plaque..

Objective To isolate and purify melanin from yeast cells of Penicillium mameffei (PM) and to analyze its physicochemical features.Methods PM yeast cells were cultured in minimal medium containing levodopa (L-dopa) with continuous shaking at 37 ℃.Melanin was isolated from the yeast cells of PM by cell walllysing enzyme,denaturant,concentrated hot acid,and purified by sodium hydroxide and concentrated hydrochloric acid.The physicochemical properties of isolated melanin were assessed on the basis of combined chemical analysis and spectroscopic methods including ultraviolet-visible (UV-vis),Fourier transform infrared (FT-IR) and electronparamagnetic resonance (EPR).Results Similar to synthetic dopa-melanin,the isolated melanin from PM was alkali soluble,acid-resistant,insoluble in water and most organic solvents,precipitated at or below PH 3,and could be bleached by hydrogen peroxide.UV-vis spectrophotometric analysis showed that the PM-derived melanin had a typical absorption peak at 205 nm and the absorbance decreased with the increase of wavelength.FT-IR spectroscopy displayed two absorption peaks at about 3 μm and 6 μm,which was characteristic of classic melanin.EPR spectroscopy revealed that the isolated melanin contained stable free radicals.Conclusion Yeast cells of PM can use exogenous L-dopa to synthesize dopa-melanin.

OBJECTIVE: To observe the changes of peristalsis of small intestine in guinea pigs after administration of traditional Chinese medicines activating blood to resolve stasis (Compound Danshen Decoction, CDSD) or/and medicines dredging intestines (Dachengqi Decoction, DCQD), and to explore the synergetic or intensive effect of CDSD on DCQD. METHODS: By means of BL-420 Biological Experimental System, peristalsis of small intestine was recorded and analyzed following administration of DCQD, CDSD or Huoxue Chengqi Decoction (HXCQD, compound of CDSD and DCQD) respectively in different experimental periods. RESULTS: The amplitude and frequency of intestinal peristaltic wave obviously increased following administration of the three decoctions, but HXCQD appeared to be most dominantly. CONCLUSION: The effect of DCQD can be further enhanced by combining use of CDSD, suggesting that the traditional Chinese medicines activating blood to resolve stasis have an intensive effect on medicines dredging intestines.

Objective To construct a recombinant lentivirus containing human beta defensins -3 ( hBD3 ) , connective tissue growth factor gene (CTGF) and enhanced green fluorescent protein (EGFP), and to detect its translation in rabbit bone marrow mesenchymal stem cells (BMSC).Methods The lentivirus containing hBD3, CTGF and EGFP genes was constructed in vitro.The titer of lentivirus was tested with end-paint dilution assay .Rabbit BMSCs were transfected with recombinant virus.The best value of multiplicity of infection (MOI) was tested.The expression condition, transfection efficacy and genetic stability of the target genes were evaluated by using fluorescence microscopy and flow cytometry . Western blotting was used to detect the expression of the target protein .Results Recombinant lentivirus vectors: Lenti-CTGF-hBD3-EGFP, Lenti-hBD3-EGFP, and Lenti-EGFP, were successfully obtained . The titer of the recombinant lentiviruses was 3.21 ×108, 5.80 ×108, and 1.16 ×109, respectively.The best MOI value to transfect BMSCs was 150. The transfection efficacy of these lentivirus vectors was high , reaching 79.72%as assessed by flow cytometry , and it could be stably inherited .Western blotting displayed that target protein expression was successful .Conclusion The construction of recombinant lentiviruses carrying hBD3 and CTGF genes is successful and can be effectively transfected into BMSCs .

Objective To probe the periodontal ligament regeneration following the implantation of bone marrow mesenchymal cells ( BMSCs ) sheet-collagen membrane-BMSCs sheet sandwich complex.Methods BMSCs cell sheet-collagen membrane-BMSCs sheet complexes were compounded on the root surface of teeth of Beagle dogs.All the dogs were killed on 4 and 12 weeks after implantation.Periodontal ligament regeneration was observed by radiological means, HE staining and Sirus-red staining.Results Compared with collagen membrane group and blank control group, there was a clearly periodontal ligament like tissue and Sharpey′s like fibres formation in test group only.Conclustion Cell sheet-collagen membrane-cell sheet sandwich complex can effectively improve the periodontal ligament regeneration.

Antimicrobial peptides are the most promising alternatives to antibiotics. However, the strategy of producing antimicrobial peptides by recombinant technology is complicated and expensive, which is not conducive to the large-scale production. Oxysterlin 1 is a novel type of cecropin antimicrobial peptide mainly targeting on Gram-negative bacteria and is of low cytotoxicity. In this study, a simple and cost-effective method was developed to produce Oxysterlin 1 in Escherichia coli. The Oxysterlin 1 gene was cloned into a plasmid containing elastin-like polypeptide (ELP) and protein splicing elements (intein) to construct the recombinant expression plasmid (pET-ELP-I-Oxysterlin 1). The recombinant protein was mainly expressed in soluble form in E. coli, and then the target peptide can be purified with a simple salting out method followed by pH changing. The final yield of Oxysterlin 1 was about 1.2 mg/L, and the subsequent antimicrobial experiment showed the expected antimicrobial activity. This study holds promise for large-scale production of antimicrobial peptides and the in-depth study of its antimicrobial mechanism.
Elastin ; Escherichia coli/genetics* ; Inteins ; Peptides/pharmacology* ; Pore Forming Cytotoxic Proteins ; Recombinant Fusion Proteins/genetics*

Objective To assess the value of preoperative MRI in predicting the incidence of cement leakage into adjacent discs during percutaneous vertebral augmentation (PVA) for osteoporotic vertebral compression fracture (OVCF).Methods Clinical and radiological characteristics of 127 patients who were treated with PVA for OVCF were analyzed retrospec tively.The following clinical data of these patients were analyzed,including gender,age,location of treated vertebral body and surgical approach.The image features of endplate injury,fracture line extended to the endplate,adjacent intervertebral dick injury and intravertebral cleft were evaluated on the preoperative MRI.The incidence of cement leakage into the adjacent disc were compared for the above factors with statistical methods.Results Totally 127 patients were enrolled in our study,including 179 treated vertebral bodies,358 endplates and 341 adjacent intervertebral discs.The incidence of intradiscal cement leakage was 57.73％ (56/97) in endplate injury sign,60.98％ (25/41) in fracture line extended to endplate sign,35.91％(51/142) in adjacent discs injury sign and 55.56％(20/36) inintravertebral cleft sign.The differences were statistically significant on preoperative MRI in patients with the above signs compared to those who had not (P＜0.05).The incidence of intradiscal cement leakage in percutaneous kyphoplasty (PKP) and percutaneous vertebroplasty (PVP) were 26.67％(16/60) and 42.86％(51/119),respectively,which was significant different (P=0.035).For bone cement volume ≤ 5 ml vertebral bodies,the incidence of intradiscal cement leakage was 31.19 ％ (34/109),lower than bone cement volume ＞ 5 ml vertebral bodies (47.14％ [33/70],P=0.031).There was no statistically significant association between intradiscal cement leakage and age,gender and location of treated vertebral body (P＞0.05).Conclusion Preoperative MRI can predict the leakage of bone cement into adjacent discs effectively during PVA.The PKP and the lower volume of bone cement injection can reduce the risk of intradiscal cement leakage.