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Objective@#To observe the effect of calcium on biological characteristics (proliferation, apoptosis and cell cycle) of ALC ameloblasts. .@*Methods@#ALC cell lines were cultured in vitro in DMEM medium with high glucose at different concentrations (0, 2.0, 2.5, 3.0 and 3.5 mmol/L CaCl2 aqueous solution) for 24 h and 48 h, respectively. Changes of ALC cells under two kinds of incubation time were observed with an inverted microscope. CCK-8 method was used to analyze the effect of calcium ion on ALC cell proliferation. Hoechst staining was used to observe the effect of calcium ion on ALC cell apoptosis. PI staining and FCM method were used to analyze the effect of calcium ions on the growth cycle of ALC cells. Western blot was used to detect the effect of calcium ions on the expression of Cyclin A, Cyclin B and Cyclin D in ALC cells@*Results@#In the 0 mmol/L CaCl2 group, ALC cells were oval or polygonal in shape, and the cells were closely connected and grew like paving stones. In other concentration groups, the morphology of ALC cells did not change significantly after calcium intervention for 24 h and 48 h. Results of CCK-8 method showed that the survival rate of ALC cells slightly decreased with increasing calcium ions concentration after calcium intervention for 24 h and 48 h. However, there was no significant differences in this trend. Results of Hoechst staining showed that the number of ALC cell apoptosis did not increase significantly after different concentrations of calcium intervention for 24 h and 48 h. With the increase of calcium ion concentration, results of PI staining and FCM method showed that the cell cycle of ALC cells gradually increased in S phase and decreased in G1 and G2 phase gradually. Western blot results showed that the expression of Cyclin A and Cyclin B in ALC cells decreased and the expression of Cyclin D increased after different concentrations of calcium intervention for 24 h and 48 h. @*Conclusion@#In this study, calcium has no significant effect on the proliferation and apoptosis of ALC cells. Calcium, however, has an effect on the ALC cell cycle. Results of this study show that calcium ions has no obvious toxic or side effects on the ameloblasts, which could be used to explore the possible mechanism and effect of calcium on dental fluorosis.
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【Objective】 To explore the effect of low levels of calcium on the biological characteristics of ameloblasts. 【Methods】 Rat primary ameloblasts were cultured in standard DMEM medium. After five days they were identified by RT-PCR and immunohistochemistry. Then 0, 0.6 and 1.2 mmoL/L Ca2+ and 100 mL/L fetal bovine serum were added into DMEM medium without calcium. After 48 hours, the cell morphology was observed by inverted microscope. The proliferation and apoptosis of cells were separately examined by MTT and AnnexinV-PI. Real-time quantitative PCR was used to detect the expression levels of amelogenin and KLK4 mRNA. 【Results】 After Five days in standard DMEM medium, the cells were shaped like the paving pattern. RT-PCR showed that both amelogenin and KLK4 were expressed in the cells. Immunohistochemical staining showed that most cells had positive staining for amelogenin. After 48 hours of calcium intervention, some cells in 1.2 mmoL/L Ca2+ group had higher nuclear density and poor light transmittance, and more high columnar cells could be observed in 1.2 mmoL/L Ca2+ group than those in 0 and 0.6 mmoL/L Ca2+ groups. With the decrease in calcium concentration in the medium, MTT showed that the proliferation activity of ameloblasts reduced (P<0.01). Annexin V-PI showed that the percentage of apoptotic cells decreased, and there was a significant difference between 1.2 mmoL/L and 0 mmoL/L Ca2+ groups (P<0.05). Real time-PCR showed that the expressions of amelogenin and KLK4 mRNA reduced (P<0.01). 【Conclusion】 Low-level calcium may inhibit the differentiation of ameloblasts, thereby affecting the formation of enamel mineralization.
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Objective This study aims to understand the characteristics of the time sequence of ICR mouse first mandibular molar tooth germ development through dynamic observation.Methods Tooth germ of Embryos (E11.5,E12.5,E13.5,E14.5,E15.5,E16.5,E17.5 and E18.5) and postnatal (PN1,PN2) mice were obtained.The heads (E11.5-E15.5) and mandibles (E16.5-PN2) of mice were dissected,fixed and embedded for serial sections and HE staining.All the results were assessed under light microscopy.Results The tooth germ underwent various development stages including the bud,cap and bell stages.Mouse odontogenesis was initiated at E11.5.Proliferation of oral epithelium formed the bud stage at E13.5.Then the cap stage was observed at E14.5-E15.5 and the bell stage was appeared beginning from E16.5.The pre-dentin was observed at PN1,as well as the dentin at PN2.Conclusions Establishing the regular development pattern of the first mandibular molar of ICR mice will provide a reliable basis for the future use in the specific tooth germ developmental research.
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Objective:To evaluate the effect of pinus massoniana bark extract (PMBE) and grape seed extract (GSE) on dentin demineralization caused by acid.Methods:40 root dentin blocks with half of the surface covered were randondy divided into 4 groups (n =10).All samples were subjected to pH cycling for 8 days,and deionized distilled water(DDW),0.1％NaF,12％ PMBE solution and 12％ GSE solution were used as the experimental solutions in the 4 groups.The dentin mineral density(DMD) of the both sides was determined using micro-computed tomography.The D-value of DMD between nn-demineralized and demineralized side (△DMD)was calculated.The samples were observed with field emission scanning electron microscops (FE-SEM).Results:The △DMD of DDW,NaF,PMBE and GSE groups was 198.64 ±59.97,45.94 ±24.21,90.23 ±28.77 and 105.07 ±29.53 respectively.The △DMD between PMBE and GSE groups had no significant difference (P ＞ 0.05),which were both higher than that of NaF group (P ＜ 0.05) and lower than that of DDW group(P ＜ 0.05).The FE-SEM revealed that the dentin tubules in DDW group were completely open,but in NaF group were essentially closed in PMBE group and GSE group were spindle shaped or narrow crack opening.Conclusion:PMBE and GSE had almost the same effect on improving the acid resistance of dentin.
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Objective To investigate the diagnostic value of texture analysis derived from conventional MR imaging in differentiating benign and malignant breast lesions. Methods Thirty-six patients with malignant breast lesion and 33 patients with benign breast lesion were retrospectively analyzed in our study. All patients underwent conventional MR imaging including axial T1WI, T2WI, and contrast-enhanced T1WI before surgery. Texture features were calculated from manually drawn ROIs by using MaZda software. The feature selection methods included mutual information (MI), Fishers coefficient, classification error probability combined with average correlation coefficients (POE + ACC) and the combination of the above three methods(FPM). These methods were used to identify the most significant texture features in discriminating benign breast lesion from malignant breast lesion. The statistical methods including raw data analysis (RDA), principal component analysis (PCA), linear discriminant analysis (LDA) and nonlinear discriminant analysis (NDA) were used to distinguish malignant breast lesion from benign breast lesion. The results were shown by misclassification rate. Results In the three kinds of sequences, the texture features for differentiating malignant breast lesion and benign breast lesion were mainly from T2WI which had the lowest misclassification rate 4.35%(3/69). The misclassification rates of the feature selection methods were similar in MI, Fisher coefficient and POE+ACC (15.94%to 56.52%for MI;17.39%to 56.52%for Fisher coefficient and 17.39%to 56.52%for POE+ACC). However, the misclassification rate of the combination of the three methods (4.35%to 53.62%for FPM) was lower than that of any other kind of method. In the statistical methods, NDA (4.35% to 27.54%) had lower misclassification rate than RDA (33.33% to 56.52%), PCA (33.33% to 53.62%) and LDA (15.94% to 44.93%). Conclusion Texture analysis of conventional MR imaging can provide reliably objective basis for differentiating benign from malignant breast lesions.
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<p><b>OBJECTIVE</b>This study aims to evaluate the effects of Pinus massoniana needle extract (PMNE) on inhibiting demineralization of root dentin.</p><p><b>METHODS</b>Root dentin blocks were randomly divided into distilled deionized water (DDW) group, fluoride sodium (NaF) group, and 4%, 8% and 12% PMNE groups according to the experimental solution used in the process of pH cycling in each group. All specimens in each group experienced pH cycling for 8 d. The dentin mineral density (DMD) of the normal dentin and demineralized dentin and their D-value (ΔDMD) were determined using micro computed tomography. The morphology of dentin surface after pH cycling was also observed using a scanning electron microscope.</p><p><b>RESULTS</b>The ΔDMD values in all PMNE groups and the NaF group were considerably lower than the ΔDMD in the DDW group (P<0.05). The ΔDMD values of the 8% and 12% PMNE groups had no difference (P>0.05), both of which were lower than the ΔDMD in the 4% PMNE group and higher than that in the NaF group (P<0.05). The dentin tubules were partly opened in the PMNE groups. The opening degrees of the dentin tubule in PMNE groups were significantly less and smaller than the opening degree in the DDW group and were larger than that in the NaF group.</p><p><b>CONCLUSIONS</b>PMNE can inhibit the deminera-lization of root dentin and can slow down the reduction in DMD. PMNE has the potential to prevent caries, and 8% PMNE can effectively inhibit dentin demineralization.</p>