Protective Effect and Mechanism of Ginkgolide B on Amyotrophic Lateral Sclerosis Cell Model / 中国实验方剂学杂志

Objective:To investigate the effect of ginkgolide B （GB） on the activation of c-Jun aminoterminal kinase（JNK） signaling pathway and apoptosis in amyotrophic lateral sclerosis cell model. Method:NSC34 cells were infected by slow virus containing expression superoxide dismutase1（SOD1）WT and hSOD1G93A and empty plasmid， and screened with a certain concentration of puromycin， so as to observe the transfection efficiency of slow virus and cell morphology under inverted fluorescence microscope. Western blot method was used to verify whether infected cells were over-expressing SOD1 target proteins. The hSOD1G93A-NSC34 cell lines were established and given GB. Cell cultures were divided into normal group， model group and different concentrations of ginkgolide B groups （25， 50， 75， 100 mg∙L-1）. After 48 h， methyl thiazolyl tetrazolium （MTT） was used to detect cell survival rates， and select the best drug concentration. Subsequent experimental groups were divided into normal group， model group， 75 mg∙L-1 GB group， SP600125 group， and 75 mg∙L-1 GB + SP600125 group. Flow cytometry was used to detect the apoptosis of each group of cells. Western blot was used to detect the expressions of phosphorylation（p）-JNK， c-Jun， p-c-Jun， and cysteine aspartic acid protease -3（Caspase-3） proteins. Result:Compared with normal NSC34 cells， hSOD1G93A-NSC34 cell body became round， the synapses decreased and shortened， but the cell morphology of hSODWT-NSC34 cell and empty plasmid group did not change significantly. Western blot showed that hSOD1G93A-NSC34， hSOD1WT-NSC3 intracellular SOD1 protein levels increased significantly （P<0.01）， and the amyotrophic lateral sclerosis cell model was established. Compared with the normal group， the cell activity in the model group was significantly reduced （P<0.01）. Compared with the model group， the cell activity increased at different concentrations of GB， especially when the drug concentration was 75 mg∙L-1 （P<0.01）. In subsequent experiments， compared with the normal group， the apoptosis， and expressions of p-JNK， p-c-Jun， and cleaved Caspase-3 proteins in the model group increased significantly （P<0.01）. Compared with the model group， the apoptosis and p-JNK， p-c-Jun， released Caspase-3 protein expressions of 75 mg∙L-1 GB group， SP600125 group， 75 mg∙L-1 GB + SP600125 group decreased significantly （P<0.05， P<0.01）. Conclusion:GB has a protective effect on the cell model of atrophy lateral sclerosis， which may be realized by JNK signal pathway.

Construction and mechanical analysis of finite element model for bending property of controlled memory wire nickel-titanium rotary file / 北京大学学报(医学版)

OBJECTIVE@#To construct a model for a controlled memory (CM) nickel-titanium (NiTi) file and another M-wire NiTi file with the same geometry by using finite element analysis. To evaluate the flexibility of a CM NiTi file by using three dimensional finite element method and to compare its mechanical responses with that M-wire NiTi.@*METHODS@#Based on the reverse engineering, the 21 mm long, 25#/08 taper Hyflex NT NiTi file and Hyflex CM NiTi file were fixed by the cantilever bending model at a distance of 9.5 mm from the tip of the file. The mechanical tester's indenter was loaded/unloaded at a distance of 3 mm from the tip of the file. The maximum displacement was 3 mm, the load displacement curve was obtained. Subsequently, by using a micro-CT to scan (layer spacing of 8 μm) NiTi files, and ABAQUS (6.10) was introduced to construct a geometric model. Hyflex NT was considered as a shapememory alloy constitutive model, Hyflex CM was considered as a power-hardening plastic constitutive model, respectively. Comparing the load-displacement curve of cantilever bending in the three-dimensional finite element model with the load-displacement curve in the experiment.@*RESULTS@#Two tetrahedral element models were constructed, the total number of nodes was 99 353 and the total number of cells was 63 744. When the loading displacement was 1 mm, the stress distribution of the cross section at 6.1 mm from the tip of the file was observed. The upper and lower surfaces were subjected to the maximum bending stress and entered the phase transformation yield stage. The finite element simulation could clearly show the deformation of the file. Various information such as deformation characteristics and stress distribution in the process were well fitted to the actual experimental curve.@*CONCLUSION@#The constitutive behavior of the material has a significant effect on the mechanical behavior of NiTi file. The finite element model established for the NiTi file of the CM wire can accurately capture the characteristics of various deformation processes of the NiTi root canal file, and it has a good fit with the actual experimental curve. The finite element model can be used for study on bending properties of CM wire.

Glide path management of rotary nickel-titanium instruments in simulated root canals / 北京大学学报(医学版)

OBJECTIVE@#To compare the shaping ability of ProGlider, HyFlex EDM Glidepath File and RaCe ISO 10 with that of PathFile and stainless steel K-file hand instruments in simulated root canals.@*METHODS@#A total of 60 simulated resin blocks were divided randomly into five groups (n=12), each group prepared with each instrument, respectively. Preparation time was recorded. Pre- and post-operative images were obtained using a scanner and superimposed using Photoshop. The material removal from the inner and outer canal walls beginning from 0 mm at the end point of the canal were measured using ImageJ. Centering ability was determined, accordingly. The data were analyzed using the One-Way ANOVA at a significance level of P<0.05.@*RESULTS@#Preparation time for ProGlider was (61.018±5.020) s, significantly the fastest (P < 0.05), that for SS K-file (111.100±6.987) s, the slowest (P<0.05), and the differences among the other 3 groups were not significant (P>0.05). The removal of resin from the outer wall at the apical portion was significantly lower for HyFlex EDM Glidepath File than for ProGlider (P<0.05), both of them were significantly lower than the other 3 groups (P<0.05). For the removal from the inner wall at the curvature portion, ProGlider was the least whilst SS K-file the most (P<0.05). At the straight portion, RaCe ISO 10 removed the most not only from the inner but also the outer wall (P<0.05), HyFlex EDM Glidepath File the second most, and the other 3 groups among the same levels. As far as the centering ability was concerned, at the apical portion, HyFlex EDM Glidepath File was the best, ProGlider the second best, no significant difference identified among the other 3 groups. At the curvature portion, ProGlider and HyFlex EDM Glidepath File were the best, PathFile the second, RaCe ISO 10 the third, the worst was the SS K-file. At the straight portion, the difference amongt the 5 groups was not significant.@*CONCLUSION@#The shaping abilities of ProGlider, HyFlex EDM Glidepath File and RaCe ISO 10 were better or comparable to that of PathFile, while the preparation time for ProGlider reduced significantly, and HyFlex EDM Glidepath File and RaCe ISO 10 removed significantly more resin at the straight portion of the canal.

Effect of autoclave on surface microstructure and cyclic fatigue resistance of R-phase rotary instruments / 北京大学学报(医学版)

OBJECTIVE@#To compare the effects of autoclave on surface microstructure and cyclic fatigue resistance of K3XF and K3.@*METHODS@#Forty-eight size 25, 0.06 taper 25 mm-long K3XF or K3 were randomly divided into 4 groups (n=12). The instruments from group 1 were not autoclaved, and the groups 2 to 4 underwent autoclave for 10 cycles, 20 cycles, and 30 cycles, respectively. The surface microstructure of two instruments randomly selected from each group was observed using scanning electron microscope (SEM). The remaining 10 instruments were submitted to the cyclic fatigue test by using a simulated metal root canal with curvature of 60° and radius 3.5 mm. The time till fracture was recorded, the number of cyclic fatigue (NCF) calculated, the fragment length evaluated, and the topographic features were analyzed using SEM. The data were analyzed using the two-way ANOVA analysis by SAS 9.3 software at a significance level of P<0.05.@*RESULTS@#SEM observation identified rough features on the surface of K3XF with micropores existing evenly. K3 was characterized by machining grooves, which located specifically in the flute, leaving a smooth cutting edge. After autoclave, SEM observation indicated that the micropores in the surface of K3XF became larger and more, whereas the machining grooves in the surface of K3 were squeezed, out of shape and flaking. As far as the NCF was concerned, new K3XF was 210±59, and no significant difference was found after 10, 20, and 30 cycles of autoclave for K3XF, values being 178±37, 208±48, and 227±43, respectively (P>0.05). For K3, the new one was 145±38, and no significant difference in NCF was demonstrated after 10 and 20 cycles of autoclave, with the values of 128±43 and 124±46, respectively (P>0.05). However, after 30 cycles of autoclave of K3, significant increase to 216±38 was identified (P<0.05). Topographic features demonstrated typical cyclic fatigue for all the groups.@*CONCLUSION@#The surface roughness of K3XF was increased after autoclave, while the cyclic resistance remained stable after up to 30 cycles.

Surface microstructure and cyclic fatigue resistance of electro discharged machining nickel-titanium endodontic instrument / 北京大学学报(医学版)

OBJECTIVE@#To compare the surface microstructures and cyclic fatigue resistance of HyFlex EDM with HyFlex CM and HyFlex NT.@*METHODS@#Twelve 25 mm-long 25#/- HyFlex EDM and twelve 25 mm-long 25#/0.06 taper HyFlex CM or HyFlex NT were selected. The surface microstructure of the 2 instruments which were randomly selected from each group was observed by using scanning electron microscope (SEM). The remaining 10 instruments from each group were submitted to the cyclic fatigue test by using a simulated stainless steel root canal with 60° angle of curvature and curvature radius of 3.5 mm. The time till fracture was recorded, the number of cyclic fatigue (NCF) was calculated, the length of fracture fragment was evaluated, and the topographic features were analyzed by using SEM. The data were analyzed by using one-way analysis via SPSS 23.0 software. The statistical significance level was set at 0.05.@*RESULTS@#SEM observation of the surface and microstructural characterization revealed peculiar melting appearance and evenly distributed micropores on the surface of HyFlex EDM while observations of the surface of both HyFlex CM and HyFlex NT demonstrated machining grooves and irregularities. The NCF of HyFlex EDM was 838±223, which was significantly higher than not only that of HyFlex CM (582±99), but also that of HyFlex NT (81±20) (P<0.05), and the difference between the latter two groups was significant, as well (P<0.05). The length of fractured fragments of HyFlex EDM was (7.27±0.28) mm, which was significantly longer than the HyFlex CM and HyFlex NT, with values of (6.72±0.26) mm and (6.62±0.37) mm, respectively (P<0.05). Topographic features demonstrated typical cyclic fatigue for all the three groups while the region of crack origins was more for HyFlex EDM and HyFlex CM than that of HyFlex NT. As far as the dimple area was concerned, that of HyFlex EDM was deeper and larger than that of HyFlex CM and HyFlex NT.@*CONCLUSION@#Within the limitations of this study, electro-discharge machining leads to peculiar melting appearance with micropores instead of machining grooves and irregularities on the surface of HyFlex EDM, which may be the reason why HyFlex EDM exhibits significantly better cyclicfatigue resistance than HyFlex CM and HyFlex NT.

Role of microRNA in chronic hepatitis B, liver cirrhosis and hepatocellular carcinoma / 第二军医大学学报

Hepatitis B virus (HBV) infection and the subsequent persistent inflammation are the important factors that facilitate the development of liver cirrhosis and hepatocellular carcinoma. Both HBV infection and persistent inflammation can affect carcinogenesis via regulating microRNA expression. Aberrant expression of microRNAs plays an important role in regulating the malignant transformation of chronic inflammation. Some microRNAs can aggravate inflammation via increasing HBV replication or expression of inflammatory factors, some can promote fibrosis process via activating hepatic stellate cells or producing collagen proteins, and some can promote cancer progression by affecting the balance between cancer promoting factors and tumor suppressor factors. Proinflammatory molecules can promote Evo-Dev of HBV-induced hepatocellular carcinoma through epigenetic regulation including regulating the expression of microRNAs. Here in this review we discussed the potential mechanisms by which persistent inflammation induces aberrant expression of microRNAs and the role of dysregulated microRNAs in the development of chronic hepatitis B, liver cirrhosis, and hepatocellular carcinoma.

Impact of viral genotypes and their mutations on the occurrence of hepatocellular carcinoma among HBV infected patients：a cohort study / 上海预防医学

Objective] To investigate the relationship between hepatitis B virus( HBV) genotype and their mutations on the development of hepatocellular carcinoma ( HCC ) . [ Methods ] A cohort study on patients with chronic HBV infection was followed up.HBV genotypes were identified by nested multiplex PCR and multiplex PCR.And HBV mutations in the basic core promoter region were sequencing by PCR amplification. [ Results] The patients infected with genotype B were followed up for an average of 8.52 years (IQR:6.67-10.75), of whom the incidence of HCC was 6.55/1 000 person-years.After follow up with an average of 8.87 years (IQR:6.85-11.33), the incidence of HCC was 11.63/1 000 person-years for the patients infected with genotype C, which were significantly higher than those infected with genotype B (P=0.006).In genotype B HBV infected patients, age (≥60 years), cirrhosis can in-crease the risk of HCC, and in genotype C patients, male, age (≥40 years), cirrhosis, C1653T, T1753V, A1762T/G1764A mutation as well.Interferon therapy can reduce the risk of HCC.In genotype C group, interferon treatment reduced HCC risk in patients carrying A1762T/G1764A mutation (HR=0.21, P=0.008) and in those without T1753V ( HR=0.08, P=0.012) and C1653T mutation ( HR=0.17, P=0.013). [Conclusion] HBV genotypes and mutation are closely associated with HCC.Patients infected with genotype C, carrying 1762T/G1764A mutation should be given priority of receiving antiviral treatments in order to prevent HCC;those carrying C1653T or T1753V mutation should be monitored closely to detect early HCC and receive timely surgical resection.

Prevalence of dental erosion and associated drinks in 12-year-old population of Beijing / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the prevalence of dental erosion and associated drinks in 12-year-old adolescence of Beijing.</p><p><b>METHODS</b>A random sample of 12-year-old adolescence of Beijing (n=844) was examined for dental erosion and required to fill a questionnaire of acidic drink intake. The grade criteria suitable for the survey of the dental erosion was used in the study.</p><p><b>RESULTS</b>The prevalence of dental erosion was 61.8%, of which mild enamel was 74.1%, severe enamel erosion 24.9% and dentine erosion 1.0%. Statistic analysis showed that a large amount of intake of carbonated drink or juice were risk factors.</p><p><b>CONCLUSIONS</b>Attention should be paid to the prevalence of dental erosion among Chinese adolescence.</p>

Pilot study of dental erosion and associated factors in university student volunteers / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate dental erosion and associated etiologic factors among students from one university.</p><p><b>METHODS</b>A total of 179 student volunteers from one university were examined clinically for their dental erosion. Each was required to complete a questionnaire regarding potentially associated etiologic factors. A modified criteria was used to grade the severity of dental erosion.</p><p><b>RESULTS</b>The prevalence of dental erosion of this group was 45.8%, mostly in enamel. Facial surfaces of anterior teeth were most vulnerable to erosion. Statistic analysis indicated that acidic diets, such as carbonated drink, fruit juice, fruit drink and banana were risk factors to dental erosion.</p><p><b>CONCLUSIONS</b>The findings strongly suggest that much attention should be given to dental erosion which was probably associated with acidic diet.</p>