ObjectiveTo evaluate the theoretical knowledge level of Chinese students majoring in stomatology based on the problem-based learning (PBL).MethodsThe Cochrane reviewer's handbook was followed by.Domestic published articles from 1989 -2010 were selected by computer and handwork.All these retrieved studies were controlled clinical trials related to oral theoretical education and were conducted by PBL and the traditional teaching methods.The quality of included studies was critically evaluated and the data were analyzed by the RevMan 5.0.1 software.ResultsA total of 138 articles were selected,but only 8 were included.Significant differences were found when the data were pooled(P ＜ 0.01,I2 =80％ ) and random effect model was used for meta-analysis.The results showed that comparing with the traditional teaching methods,PBL can improve the theoretical score of dental students [ MD 5.39,95％ CI(2.20,8.58)],and sensitivity analysis showed that the result was stable.ConclusionPBL can improve the theoretical score of Chinese students majoring in stomatology.However,as part of the studies are not high quality literature,the above conclusion needs to be verified by more large sample-sized,rigorously designed randomized controlled clinical trials.

OBJECTIVE: To study the role of nuclear factor-kappa B (NF-kappaB) and cycloxygenase-2 (COX-2) in the onset of phlegm obstruction due to lung-deficiency in rats and the therapeutic mechanism of Huatan Recipe. METHODS: Twenty-four SD rats were randomly divided into normal group, model group and treatment group, with 8 rats in each group. The rats in the model group and treatment group were exposed to sulfur dioxide and cold wind to establish the rat model of phlegm obstruction due to lung-deficiency, and the rats in the treatment group were also treated with Huatan Recipe, a compound traditional Chinese medicine. The expression of NF-kappaB in the bronchial epithelial cells of the rats was tested with the method of immunohistochemistry, and the COX-2 mRNA in the lung tissues of the rats was measured by using reverse transcription-polymerase chain reaction. RESULTS: The expressions of NF-kappaB and COX-2 mRNA in rats of the model group were higher than those of the normal group (P<0.01), and the expressions of NF-kappaB and COX-2 mRNA in rats of the treatment group were obviously lower than those of the model group (P<0.01). CONCLUSION: The NF-kappaB and COX-2 play an important role in the onset of phlegm obstruction in rats. Huatan Recipe may prevent the development of phlegm obstruction by down-regulating the expressions of NF-kappaB and COX-2 mRNA.

OBJECTIVE:To prepare the levofloxacin(LEF)thermosensitive gel for ophthalmic drug delivery,and to study the drug release in vitro.METHODS:Poloxamer407was used as themosensitive material for the LEF eye drop,the best con?centration of poloxamer in prescription was selected according to the temperature of gel,a novel membraneless model was used to study the drug release.RESUTS:The detected concentration of LEF was in the linear range of3～11?g/ml(r=0.9991,n=6),the recovery was99.62%;The best concentration of poloxamer in prescription was18%;Drug release followed zero-order kinetics,and the quantity of drug release was controlled by that of gel dissolution.CONCLUSION:The preparation is simple in method and easy to control in dosage,therefore it shows a promising future in development.

AIM: To detect dystrophin expression in skeletal muscles of mdx mice after bone marrow transplantation (BMT), and to evaluate the effect of BMT on Duchenne muscular dystrophy (DMD). METHODS: Bone marrow cells were cultured for three days, and then transplanted into mdx mice irradiated lethally through tail veins. After 4 and 6 months, dystrophin expression on myocytes membranes in mdx mice was detected by fluorescent immunohistochemical staining. The centrally nucleated fibers (CNF) were calculated by HE staining, and the physiologic parameters measured and the motor function detected by traction test, rotating rods test and rotating wheels test were also observed. RESULTS: Until 4 and 6 months after BMT, dystrophin was expressed partly on myocytes membranes in mdx mice, and the ratio of CNF decreased, physiologic functions improved, the motor ability reinforced in treated group. CONCLUSION: After BMT, marrow stem cells settled in injured skeletal muscles and bone marrow, then differentiated into myocytes with dystrophin expression and caused the improvement of pathology, physiology and motor function in treated group finally. These results give a powerful proof for the treatment of DMD with BMT.

Objective To investigate the effects and mechanism of evodiamine on the proliferation and apoptosis of osteosarcoma MG-63 cells.Methods MG-63 cells were cultured with evodiamine for 24 hours,and the cell proliferation was evaluated by methyl thiazolyl tetrazolium (MTT) assay.Cell cycle arrest,apoptosis and intracellular Ca2+ accumulation were evaluated by flow cytometry.BALB/C mice model of osteosarcoma was established to investigate the tumor inhibitory effect of evodiamine on human osteosarcoma.Wnt/β-catenin signaling protein expressions in osteosarcoma cells were detected by Western blotting.Results As concentration of evodiamine increasing (0.25 μmol/L,0.5 μmol/L,1.0 μmol/L,2.0 μmol/L and 4.0 μmol/L),the inhibition rate of MG-63 ceils increased [(4.18 ± 1.26)％,(15.49 ± 2.26)％,(40.55 ± 6.57)％,(49.87 ±7.69)％ and (60.42 ±8.29)％].The difference was statistically significant between 2.0 μmol/L group and the control group (t =-2.66,P ＜ 0.05).MG-63 cells were cultured with 2.0 μmol/L evodiamine for 24 hours,and the apoptotic rate was (64.67 ± 8.63) ％,the proportion of S phase cells was (85.33 ± 9.31)％,the fluorescence of Ca2+ was 97.33 ± 21.31.The corresponding data of the control group were (4.94 ± 0.81) ％,(43.67 ± 8.92) ％ and 28.67 ± 8.92,the differences were statistically significant (t =-11.90,P ＜ 0.05;t =-7.22,P ＜ 0.05;t =-6.65,P ＜ 0.05).On mice model,the tumor weight of evodiamine group and the control group was (2.15 ±0.35)g and (4.29 ±0.49)g respectively,the difference was statistically significant (t =7.95,P ＜ 0.05).Comparing with the control group (1.00 ± 0.00),evodiamine decreased the expression of β-catenin protein (0.72 ± 0.36) and increased the expressions of Bax (1.15± 0.27) and Caspase-3 (1.46 ± 0.18) protein,and the differences were statistically significant (t =-3.05,P ＜ 0.05;t =-6.42,P ＜ 0.05;t =-5.85,P ＜ 0.05).Conclusion Evodiamine inhibits proliferation and induces apoptosis of human osteosarcoma MG-63 cells by blocking Wnt/β-catenin signaling.

Objective To investigate the status of dental caries of deciduous teeth among preschool children from private kin-dergarten in Chongqing city.Methods According to the criteria recommended by The Third National Oral Health Investigation,the deciduous caries of 2 713 preschool children aged 3 to 6 years from 40 private kindergartens in Yuzhong district were examined.The prevalence of dental caries and the mean dmft were calculated.The results were analyzed using SPSS21.0 software package. Results The prevalence of dental caries was 61.04%.The mean dmft score was 3.12,the filling rate was 0.4%.The caries preva-lence of 3-,4-,5-,6-year-old children were found to be 42.51%,59.53%,67.76% and 74.85%,and the mean dmft score were 2. 71,3.68,3.96 and 4.09.The prevalence of dental caries and mean dmft increased gradually as the children was statistically signifi-cant(P <0.05).The caries prevalence of male and female children were 61.65% and 60.41%,the mean dmft were 3.11 and 3.13, the difference was not statistically significant (P >0.05).Conclusion Deciduous dental caries of preschool children from private kindergartens was an important problem in Chongqing city,and the filling rate was very low.

To determine the efficacy and safety of Zhenjujiangya tablets combined with long-acting antihypertensive drugs in the patients with hypertension. Methods:A controlled study was carried out among 220 patients meeting the inclusion / ex-clusion criteria. All the patients were randomly divided into the experimental group and the control group. Both groups were treated with long-acting antihypertensive drugs as usual. The 110 patients in the experimental group were orally treated with Zhenjujiangya tab-lets ( bid) , while the other 110 patients in the control group were orally treated with Zhenjujiangya simulated tablets ( bid) , and the treatment course was 4 weeks. The efficacy was assessed using the reduction range of blood pressure, the clinical symptom score of hy-pertension and the indicators of ambulatory blood pressure monitoring as the indices, and the safety was assessed by the symptoms, signs and laboratory tests. Results:After the four-week treatment, the systolic blood pressure, diastolic blood pressure and hyperten-sion clinical symptom score were significantly decreased in the two groups, and the changes in the experimental group were more signifi-cant than those in the control group (P<0. 01). The effect on the clinical symptom of the experimental group was better than that of the control group (P<0. 01). There was no significant difference in systolic blood pressure, diastolic blood pressure and the number of abnormal blood pressure in 24h, daytime and nighttime (P>0. 05). After the treatment, the changes in average systolic blood pres-sure in 24h and daytime in the experimental group showed statistically significant difference (P<0.05),while those in the control group were without statistically significant difference (P>0. 05), and the number of abnormal blood pressure in 24h and daytime in the experimental group exhibited reduction trend. There were no significant difference in the incidence of adverse events between the two groups (P>0. 05). Conclusion:Long-acting antihypertensive drugs combined with Zhenjujiangya tablets can further improve the antihypertensive efficacy without significant adverse reactions, which is suitable for clinical application.

ObjectiveTo observe the effects of different angles between tibial tunnel and tibial platform on “killer turn” in posterior cruciate ligament (PCL) reconstruction,and primarily discuss a safe and reasonable tunnel technology. Methods Eighteen fresh tendon grafts were used to reconstruct the PCL on the tibial side of fresh cadavers.The tibial tunnels of all specimens were built via anteromedial approach.Based on the different angles between tibial tunnel and tibial platform,all specimens were divided into Group A (30°),Group B (40°) and Group C (50°),with six specimens in each group.Area of tibial tunnel exit,pressure of tibia tunnel exit and circulation characteristics of tendons under the cyclic load before and after biomechanical test were recorded.ResultsThe area of tibial tunnel exit had statistical difference among three groups after the test ( F =8.80,P ＜ 0.05 ).The pressure of tibial tunnel exit had statistical difference among three groups (F =3.91,P ＜ 0.05 ).The cyclic frequency and fatigue strength of the transplanted tendons had statistical difference among three groups under the same cyclic load ( 256 N ) and same frequency ( 126 Hz ) ( F =4.25,P ＜ 0.05 ).Conclusions The angle between tibial tunnel and tibial platform has negative correlation with the area and pressure of tibial tunnel exit,and has positive correlation with the cyclic frequency and fatigue strength of the transplanted tendons under cyclic load.The ideal anatomy position of the tibial tunnel is the anteromedial tunnel with the angle of 40° between the tibial tunnel and the tibial platform.

ObjectiveTo develop an EZ screw remover for screwing out the skidded screws,discuss its design features and biomechanical characteristics and verify its extracting effect by clinical applications.MethodsFresh skeleton specimens were used in the study,including the femur (n =3),tibia ( n =3 ),radius and ulna ( n =3 ).The screws were fixed to the specimens according to clinical requirements and bone cement was filled into the medullary cavity.The specimens were randomized into three biomechanical test model groups,ie,Group A (measuring the skidded screws with the biggest torsion when the screws were taken out by screwdriver),Group B (measuring the skidded screws with the biggest torsion when the screws were taken out by one handle of EZ screw remover) and Group C ( measuring the skidded screws with the biggest torsion when the screws were taken out by two handles).The fixed screws were divided into two types of φ4.5 mm and φ3.5 mm.The experimental specimens were tested on the universal testing machines to measure the maximum torque,torsion angle,power consumption value and efficiency when drawing out the screws. The experimental data were compared between groups.The skidded screws encountered in clinical were taken out with EZ screw remover to verify the extracting effect.ResultsThe pullout torque in Groups A,B and C was 2.87-3.27 N · m,3.06-4.83N · m and 4.12-8.36 N · m respectively ( P ＜ 0.05 ).The average torsion angle value in each corresponding group was 0.77°,0.28°,0.16° respectively (P ＜ 0.05 ).When the screws were screwed out,the average power consumption was 21 J,32 J and 45 J in Groups A,B and C respectively and power ( mechanical efficiency) was 0.35 J/s,0.53 J/s and 0.75J/s in Groups A,B and C respectively,with significant differences ( P ＜ 0.05 ).Seventeen pieces of the cannulated skidded screws of φ7.3 mm in seven patients were successfully taken out by using the EZ screw remover.ConclusionEZ screw removerhas enough resistance strength and rigidity to torsion as well as powerful clamping force and hence is an ideal tool for screwing out the skidded screw in orthopedics.

Objective To explore mechanical property changes of methyl vinyl silicone rubber modified by ferric nanoparticles and its dispersed phase.Methods Mechanical properties such as Shore A hardness,tensile strength,elongation at break,tearing rate of permanent deformation and tearing strength of pre-prepared ironic nanoparticle enhanced silicone rubber and carbon-coated ferric particle reinforced silicone rubber were tested according to national standards.A thermal field emission scanning electron microscope (TFE-SEM) was used to investigate the morphology of both surface and fracture of the composite materials and to observe the dispersion of ferric nanoparticles in them.Results Mean values of Shore A hardness,tensile strength,elongation at break,tearing permanent deformation rate and tear strength of modified composites increased with the increasing amounts of ferric nanoparticles,however,when the quota of ironic nanoparticles in the composite formula were greater than 17 phr,carbon-coated ferric nanoparticles more than 19 phr,the mean values of tensile strength of two composites stopped increasing and presented the declining trend.When the quota of ferric nanoparticles in the formula exceeding 15 phr,the mean values of elongation at break and tear strength began to decrease in the formula ratio of silicone rubber/ferric nanoparticles up to 85:15,while the Shore A hardness of samples increased all the way.Ferric nanoparticles dispersed evenly on the surface of composites.Nanopowder aggregation in the fracture surface of both composites could be observed at the formula ratio of 85:15 of silicone rubber/iron nanoparticle and 87:13 of silicone rubber/carbon-coated iron specimen.Conclusion Effect of iron nanapareticles and carbon-coated ferric nanoparticles on the mechanical properties of the reinforced methyl vinyl silicone rubber depends on the nanoparticle size,additive amount and agglomeration.