AIM To investigate the effects of heme oxygenase-1(HO-1)-modified bone marrow mesenchymal stem cells(BMMSCs)on the microcirculation and energy metabolism of hepatic sinusoids following reduced-size liver transplantati...AIM To investigate the effects of heme oxygenase-1(HO-1)-modified bone marrow mesenchymal stem cells(BMMSCs)on the microcirculation and energy metabolism of hepatic sinusoids following reduced-size liver transplantation(RLT)in a rat model.METHODS BMMSCs were isolated and cultured in vitro using an adherent method,and then transduced with HO-1-bearing recombinant adenovirus to construct HO-1/BMMSCs.A rat acute rejection model following 50%RLT was established using a two-cuff technique.Recipients were divided into three groups based on the treatment received:normal saline(NS),BMMSCs and HO-1/BMMSCs.Liver function was examined at six time points.The levels of endothelin-1(ET-1),endothelial nitric-oxide synthase(e NOS),inducible nitric-oxide synthase(i NOS),nitric oxide(NO),and hyaluronic acid(HA)were detected using an enzyme-linked immunosorbent assay.The portal vein pressure(PVP)was detected by Power Lab ML880.The expressions of ET-1,i NOS,e NOS,and von Willebrand factor(v WF)protein in the transplanted liver were detected using immunohistochemistry and Western blotting.ATPase in the transplanted liver was detected by chemical colorimetry,and the ultrastructural changes were observed under a transmission electron microscope.RESULTS HO-1/BMMSCs could alleviate the pathological changes and rejection activity index of the transplanted liver,and improve the liver function of rats following 50%RLT,with statistically significant differences compared with those of the NS group and BMMSCs group(P<0.05).In term of the microcirculation of hepatic sinusoids:The PVP on POD7 decreased significantly in the HO-1/BMMSCs and BMMSCs groups compared with that of the NS group(P<0.01);HO-1/BMMSCs could inhibit the expressions of ET-1 and i NOS,increase the expressions of e NOS and inhibit amounts of NO production,and maintain the equilibrium of ET-1/NO(P<0.05);and HO-1/BMMSCs increased the expression of v WF in hepatic sinusoidal endothelial cells(SECs),and promoted the degradation of HA,compared with those of the NS group and BMMSCs group(P<0.05).In term of the energy metabolism of the transplanted liver,HO-1/BMMSCs repaired the damaged mitochondria,and improved the activity of mitochondrial aspartate aminotransferase(ASTm)and ATPase,compared with the other two groups(P<0.05).CONCLUSION HO-1/BMMSCs can improve the microcirculation of hepatic sinusoids significantly,and recover the energy metabolism of damaged hepatocytes in rats following RLT,thus protecting the transplanted liver.展开更多
The purpose of this study was to investigate how cyclic loading influenced the fracture toughness of hot-press lithium disilicate and zirconia core materials and whether there was an increase in the propensity for cro...The purpose of this study was to investigate how cyclic loading influenced the fracture toughness of hot-press lithium disilicate and zirconia core materials and whether there was an increase in the propensity for crown failure. Two types of all-ceramic crowns including the IPS e.max Press system （n=24） and the Lava zirconia system （n=24）, were selected. Sectioned specimens were subjected to cyclic loading with the maximum magnitude of 200 N （R=0.1） until two million cycles. The material properties including Young＇s modulus （E） and hardness （H） and the fracture toughness （K,c） of the core materials were evaluated using indentation methods （n= 12 each）. The load-bearing capacities of the specimens were examined by means of monotonic load to fracture （n=12 each）. It was found that the material properties, including E, Hand Knc, of the two types of dental ceramics, were reduced. Statistical analysis indicated that there were no significant influences of fatigue loading on material properties E and H for both types of dental ceramics or Kgc for zirconia, while for the IPS e.max Press core, K,c, which was parallel to the direction of the lithium disilicate crystals, was significantly reduced （P-0.001）. A conclusion was drawn that zirconia possesses high mechanical reliability and sustainable capacity to resist fatigue loading, while fatigue loading remarkably degraded the anisotropic mechanical behaviour of hot-press lithium disilicate ceramics.展开更多
The objective of this investigation is to explore the region-dependent damage behavior of enamel, as well as to develop a good understanding of the deformation mech- anisms of enamel with numerical modeling. Nanoinden...The objective of this investigation is to explore the region-dependent damage behavior of enamel, as well as to develop a good understanding of the deformation mech- anisms of enamel with numerical modeling. Nanoinden- tation experiments have been performed to investigate the load-penetration depth responses for outer and inner enamel. Results show that the unloading curve does not follow the loading curve, and degradation of stiffness in the unloading curve is observed. Based on the experimental data, a physi- cal quantity, the chain density in protein, has been introduced to the Drucker-Prager plastic model. Numerical simulations show that the simulated load-penetration depth curves agree with the experiments, and the stiffness degradation behav- iors of outer and inner enamel are captured by the numerical model. The region-dependent damage behavior of enamel could be revealed by the numerical model. The micro dam- age affected area at inner enamel is larger than that at outer enamel, indicating that the inner enamel experiences more micro damage than the outer one. Compared with its outer counterpart, the inner enamel which is rich in organic protein could break more internal protein chains to dissipate energy and to enhance its resistance to fracture accordingly.展开更多
基金Supported by The National Natural Science Foundation of China,No.81670574,No.81441022 and No.81270528The Natural Science Foundation of Tianjin,China,No.08JCYBJC08400,No.11JCZDJC27800,and No.12JCZDJC25200the Technology Foundation of the Health Bureau in Tianjin,China,No.2011KY11
文摘AIM To investigate the effects of heme oxygenase-1(HO-1)-modified bone marrow mesenchymal stem cells(BMMSCs)on the microcirculation and energy metabolism of hepatic sinusoids following reduced-size liver transplantation(RLT)in a rat model.METHODS BMMSCs were isolated and cultured in vitro using an adherent method,and then transduced with HO-1-bearing recombinant adenovirus to construct HO-1/BMMSCs.A rat acute rejection model following 50%RLT was established using a two-cuff technique.Recipients were divided into three groups based on the treatment received:normal saline(NS),BMMSCs and HO-1/BMMSCs.Liver function was examined at six time points.The levels of endothelin-1(ET-1),endothelial nitric-oxide synthase(e NOS),inducible nitric-oxide synthase(i NOS),nitric oxide(NO),and hyaluronic acid(HA)were detected using an enzyme-linked immunosorbent assay.The portal vein pressure(PVP)was detected by Power Lab ML880.The expressions of ET-1,i NOS,e NOS,and von Willebrand factor(v WF)protein in the transplanted liver were detected using immunohistochemistry and Western blotting.ATPase in the transplanted liver was detected by chemical colorimetry,and the ultrastructural changes were observed under a transmission electron microscope.RESULTS HO-1/BMMSCs could alleviate the pathological changes and rejection activity index of the transplanted liver,and improve the liver function of rats following 50%RLT,with statistically significant differences compared with those of the NS group and BMMSCs group(P<0.05).In term of the microcirculation of hepatic sinusoids:The PVP on POD7 decreased significantly in the HO-1/BMMSCs and BMMSCs groups compared with that of the NS group(P<0.01);HO-1/BMMSCs could inhibit the expressions of ET-1 and i NOS,increase the expressions of e NOS and inhibit amounts of NO production,and maintain the equilibrium of ET-1/NO(P<0.05);and HO-1/BMMSCs increased the expression of v WF in hepatic sinusoidal endothelial cells(SECs),and promoted the degradation of HA,compared with those of the NS group and BMMSCs group(P<0.05).In term of the energy metabolism of the transplanted liver,HO-1/BMMSCs repaired the damaged mitochondria,and improved the activity of mitochondrial aspartate aminotransferase(ASTm)and ATPase,compared with the other two groups(P<0.05).CONCLUSION HO-1/BMMSCs can improve the microcirculation of hepatic sinusoids significantly,and recover the energy metabolism of damaged hepatocytes in rats following RLT,thus protecting the transplanted liver.
基金supported by the National Science Foundation of China(Grant No.11172161)the Science and Technology Commission of Shanghai Municipality(Grant No.10zr1423400)+3 种基金the Innovation Program of the Shanghai Municipal Education Commission(No.12ZZ092)the State Key Laboratory of Oral Diseases(Sichuan University)(GrantSKLODSCU2009KF03)the Shanghai Leading Academic Discipline Project(No.S30106)Instrumental Analysis and Research Centre at Shanghai University
文摘The purpose of this study was to investigate how cyclic loading influenced the fracture toughness of hot-press lithium disilicate and zirconia core materials and whether there was an increase in the propensity for crown failure. Two types of all-ceramic crowns including the IPS e.max Press system （n=24） and the Lava zirconia system （n=24）, were selected. Sectioned specimens were subjected to cyclic loading with the maximum magnitude of 200 N （R=0.1） until two million cycles. The material properties including Young＇s modulus （E） and hardness （H） and the fracture toughness （K,c） of the core materials were evaluated using indentation methods （n= 12 each）. The load-bearing capacities of the specimens were examined by means of monotonic load to fracture （n=12 each）. It was found that the material properties, including E, Hand Knc, of the two types of dental ceramics, were reduced. Statistical analysis indicated that there were no significant influences of fatigue loading on material properties E and H for both types of dental ceramics or Kgc for zirconia, while for the IPS e.max Press core, K,c, which was parallel to the direction of the lithium disilicate crystals, was significantly reduced （P-0.001）. A conclusion was drawn that zirconia possesses high mechanical reliability and sustainable capacity to resist fatigue loading, while fatigue loading remarkably degraded the anisotropic mechanical behaviour of hot-press lithium disilicate ceramics.
基金supported by the National Natural Science Foundation of China(11172161)the Science and Technology Commission of Shanghai Municipality(10410701900,11195820900 and 10ZR1423400)+2 种基金the Innovation Program of Shanghai Municipal Education Commission(12ZZ092)the State Key Laboratory of Oral Diseases(Sichuan University)(SKLODSCU2009KF03)the Shanghai Leading Academic Discipline Project(S30106)
文摘The objective of this investigation is to explore the region-dependent damage behavior of enamel, as well as to develop a good understanding of the deformation mech- anisms of enamel with numerical modeling. Nanoinden- tation experiments have been performed to investigate the load-penetration depth responses for outer and inner enamel. Results show that the unloading curve does not follow the loading curve, and degradation of stiffness in the unloading curve is observed. Based on the experimental data, a physi- cal quantity, the chain density in protein, has been introduced to the Drucker-Prager plastic model. Numerical simulations show that the simulated load-penetration depth curves agree with the experiments, and the stiffness degradation behav- iors of outer and inner enamel are captured by the numerical model. The region-dependent damage behavior of enamel could be revealed by the numerical model. The micro dam- age affected area at inner enamel is larger than that at outer enamel, indicating that the inner enamel experiences more micro damage than the outer one. Compared with its outer counterpart, the inner enamel which is rich in organic protein could break more internal protein chains to dissipate energy and to enhance its resistance to fracture accordingly.
