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Objective@#To investigate the effects of zirconia micro coating on the proliferation and differentiation of osteoblasts on the surface of zirconia ceramic, and to provide a strategy for zirconia implant surface treatment.@*Methods@#Forty tablets of zirconia ceramic, with the diameter of 15 mm and the thickness of 1.5 mm, were prepared. Then, twenty tablets polished by water sandpaper were taken as the control group, and 20 pieces of the zirconia coating after sintering micron were taken as the experimental group. The micromorphology of the surface of the two groups were observed by scanning electron microscope. The cell morphology after inoculation with MC3T3-E1 of osteoblasts on the surface of the material was investigated for 1, 3, and 5 days by scanning electron microscope. The cell proliferation was detected at 1 and 3 days by methyl thiazolyl tetrazolium. The cell differentiation ability was detected at 3 and 7 days by real-time quantitative PCR. Statistical analysis was conducted by independent sample t test.@*Results@#After coating with zirconia micron particles, pores with the diameter of 1-20 μm could be observed on the surface of the test group of tiles through high temperature sintering. The growth of osteoblasts on the surface of the ceramic chip in the test group and control group exhibited the similar cell morphology. As they were cultured for 1 day, the experimental group exhibited a similar quality of cells as those in the test group (P>0.05). After 3 days' incubation, comparing with the cell quality of the test group (1.067 ± 0.077) (P<0.05), the quality of osteoblasts on the surface of zirconia ceramics coating increased to 1.763±0.165, and the expression of mRNA in alkaline phosphatase (ALP), osteopotin (OPN) and osteocalcin (OCN) also increased with the amount of 1.63±0.28, 1.99±0.41 and 1.60±0.30, respectively, compared with the test group (1.00± 0.00) (P<0.05). Seven days later, the expression of mRNA in Runt-related transcription factor-2 (RNUX2) (1.33±0.19), special AT-rich sequence binding protein-2 (SATB2) (1.64 ± 0.36), as well as alkaline phosphatase (ALP) (1.78±0.40), OPN (2.25±0.36), and OCN (1.88±0.21), showed a remarkably increase compared with the test group (1.00±0.00) (P<0.05).@*Conclusions@#Zirconia micro coating on the surface of zirconia ceramics promoted the proliferation and differentiation of osteoblasts adhered.
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The variation in hardness of enamel is a frequently used method to evaluate the influence of whiting materials on the enamel. The purpose of this study is to improve the veracity on the evaluation tests caused by the tooth itself with point selection method. Three kinds of testing point selection methods on enamel were carried out, i. e. random selection, grid measurement and symmetrical measurement, respectively. The selected points were used to measure the micro hardness by Vickers. The influence of the variation of tooth structure itself on the hardness measurements results can be reduced by using testing point selection methods of symmetry, and thus, the accuracy of the test method used in the evaluation of the influence of dental materials on tooth hardness will be guaranteed.
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Animais , Bovinos , Esmalte Dentário , Análise do Estresse Dentário , Dentina , Dureza , Técnicas In Vitro , Clareamento Dental , Métodos , Coroa do DenteRESUMO
Objective To investigate the role of PI3-kinase-Akt-endothelial nitric oxide synthase (PI3KAkt-eNOS) signaling pathway in the attenuation of myocardial ischemia-reperfusion (I/R) injury by sevoflurane postconditioning in rats.Methods Fifty healthy male Wistar rats weighing 250-280 g aged 2-3 months were randomly divided into 5 groups ( n =10 each):sham operation group (group S),I/R group,sevoflurane postconditioning group (group Spo),sevoflurane postconditioning + dimethyl sulfoxide (DMSO) group (group Spo + D),and sevoflurane postconditioning + LY294002 (a specific PI3K inhibitor) group (group Spo+ L).I/R was produced by occlusion of anterior descending branch of left coronary artery for 30 min followed by 120 min reperfusion in anesthetized rats.In group Spo,sevoflurane was inhaled for 5 min after the end-tidal concentration reached 2.5％-3.0％ at 1 min before reperfusion.In group Spo + L,LY294002 0.3 mg/kg in 0.02％ DMSO was injected intravenously at 5 min before reperfusion,and then sevoflurane postconditioning was performed.In group Spo + D,0.02％ DMSO equal to the volume of LY294002 was injected intravenously at 5 min before reperfusion,and then sevoflurane postconditioning was performed.Arterial blood samples were taken at 120 min of reperfusion for determination of the levels of creatine kinase isoenzyme MB (CK-MB),lactate dehydrogenase (LDH) and cardiac Troponin Ⅰ (cTnI).The myocardial infarct size (IS) and area at risk (AAR) were measured and IS/AAR ratio was calculated.The rats were sacrificed at 120 min of reperfusion and the myocardial tissues in the area at risk were taken for determination of the expression of Akt,phosphorylated Akt (p-Akt),eNOS and phosphorylated eNOS (peNOS) by Western blot.The ratios of p-Akt/Akt and p-eNOS/eNOS were calculated.Results Compared with group S,the levels of CK-MB,LDH and cTnI,IS/AAR ratio,p-Akt/Akt ratio and p-eNOS/eNOS ratio were significantly increased in the other groups ( P ＜ 0.05 or 0.01 ).Compared with group I/R,no significant change was found in the parameters mentioned above in group Spo+ L (P ＞ 0.05),and the levels of CK-MB,LDH and cTnI and IS/AAR ratio were significantly decreased,and the ratios of p-Akt/Akt and p-eNOS/eNOS were significantly increased in groups Spo and Spo + D ( P ＜ 0.05 or 0.01 ).There was no significant difference in the parameters mentioned above between group Spo and group Spo + D (P ＞ 0.05).Conclusion PI3K-Akt-eNOS signaling pathway mediates the attenuation of myocardial I/R injury by sevoflurane postconditioning in rats.
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Objective: To discuss the feasibility of a new method to evaluate wearing simulators,and to investigate the feasibility of specimens' depth loss as the index of the materials' wearing resistance.Methods: Two commercial composite resins(SureFil and Spectrum TPH) were selected.The specimens were subjected to 100,200,300,400,500,800,1200,1 600 and 2 000 cycles wearing in the CW3-1 wearing system.Wearing was determined quantitatively by weighing the specimen and measuring the height of the specimen,volume loss(mm 3) and height loss(?m) were calculated.Previous clinical study results on SureFil and Spectrum TPH conducted at Hong Kong University were used to examine the relationship between clinical wearing and laboratory wearing.The difference of the wearing resistance between the two materials and the Pearson correlation of the height loss and the volume loss were analyzed by statistical software SPSS 15.0.Results: The wearing resistance of the two materials was significant difference(P
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Superoxidation of membrane lipid in corn leaf cells has been studied by researching the relationship between membrane permeability,the content of MDA,and the activity of POD and SOD under HT\|toxin stress.The experimental results showed that the content of MDA ascended,the POD activity was stimulated and SOD activity was inhibited in compatible combination,but POD activity was inhibited in incompatible combination.HT\|toxin strongly destroyed the permeability of cell membrane of corn,and there were positive correlation between toxin effect and toxin concentration and time exposure to toxin.It was conclusion that there may be toxin\|binding site in both resistant and susceptible cell membrane,and the difference in sensitivity of resistant and susceptible cells to toxin may result from their active oxygen metabolism.