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Purpose: To investigate the possible contribution of GDNF in matrix-degrading, cell-adhesion during perineural invasion (PNI) of salivary adenoid cystic carcinoma (ACC)., Methods: Totally 42 ACCs and 5 normal salivary tissues were included in the present study．Immunohistochemical staining SP method was used to detect the expression of GDNF,MMP-9,NF-κB,integrin β1 in ACC specimens and normal salivary tissues. Statistical analysis was performed using SPSS16.0 software package. RESULTS：GDNF was strongly expressed in ACC tumor cells and nerve fibers adjacent to ACC tumor cells. NF-κB, MMP-9, integrin β1 were positively expressed in ACC cell cytoplasm, integrin β1 was also found in ACC cell membrane, and NF-κB in nuclei occasionally. The positive expression rate was 69.05%（29/42）,66.67%（28/42）,61.90%（26/42）, respectively. The differences between the expression of NF-κB, MMP-9, integrinβ1 in PNI group and non-PNI group were significant (P=0.005,P=0.011,P=0.001, respectively). Expression of NF-κB, MMP-9, integrin β1 was correlated to that of GDNF(r=0.443, P=0.003; r=0.401, P=0.009; r=0.535, P=0.000, respectively). Expression of MMP-9 and integrin β1 was positively correlated to that of NF-κB(r=0.501, P=0.001; r=0.429, P=0.005). Expression of MMP-9 was correlated positively to that of integrin β1 (r=0.381, P=0.013). CONCLUSIONS：GDNF may increase the matrix-degrading and cell-adhesion of ACC in the process of PNI. NF-κB, MMP-9 and integrin β1 involve in ACC cells invading nerves.

Objective: To investigate the effect on adhesion and motion capbilities of adenoid cystic carcinoma (ACC), by detecting the expression of nerve growth factor (NGF), E-cadherin (E-cad) and S100A4 and the clinical significance in ACC tissues and analyzing the relationships between them with perineural invasion (PNI)., Methods: The expression of NGF, E-cad and S100A4 in ACC was detected with the way of immunohistochemistry SP, and then analyzing the expression level of them in different pathological types and histological regions in statistical ways on the basis of their relation with clinical and pathological parameters., Results: The expression of NGF and S100A4 in PNI group [88% (23/26) and 77% (20/26)], was higher than that in NPNI group (8/16 and 7/16, P < 0.05), and a positive correlation between them was identified in PNI group (r = 0.316, P < 0.05). However the E-cad expression was lower in PNI group [31% (8/26), P < 0.05]. On the other hand it suggested a negative correlation with NGF (r = 0.385, P < 0.05) as well as that with S100A4 (r = -0.612, P = 0.000). The expression level of NGF in fasciculus [83% (25/30)] has significant deviation compared with it in distant tumor tissues [47% (14/30), P < 0.05]., Conclusions: In the PNI process of ACC, NGF plays important parts but not the only factor. It can increase the expression and activity of S100A4 but decrease E-cad expression through binding with its receptor. Thus, adhesion abilities of tumor cells was weakened and motional abilities was strengthen.

Homeobox protein engrailed-2 (EN-2), is a subtype of the homeoprotein transcription factors of EN family. It can be transported between cells in culture by unconventional secretion and internalization mechanisms. When internalized, it can activate the transcription or translation. EN-2 had been considered to be an important transcriptional factor during the embryonic development , it involved in the regulation of anteroposterior polarity. In recent years, much more functions of EN-2 are revealed. It controls synaptic choice as well as axon projections; and there are some relationships between EN-2 and Parkinson's disease. Furthermore, EN-2 is thought to be a candidate oncogene in human breast cancer and a candidate gene of Autism Spectrum Disorder. The structure, distribution, function and regulation of EN-2 as well as the relationships between EN-2 and some diseases are reviewed in the present article.

Objective: To evaluate the effect of gilding technique on the release of element from copper-based alloy post-core exposed to artificial saliva., Methods: The quantities of nickel ion and copper ion released from common copper-based alloy post-core (control group), blasting gilding copper-based alloy post-core (blasting group) and burnishing gilding Copper-based alloy post-core (burnishing group) in artificial saliva after 1 month,3 months,6 months and 8 months of exposure were measured with atomic absorption spectrophotometer. The tooth tissues were stripped off at the eighth month and the oxygenization on the surface of the posts were observed., Results: There was a significant difference of element release of nickel between the gilding groups and the control group at the sixth and eighth month. There was a significant difference of element release of copper between the gilding groups and the control group at the third, sixth and eighth month. The quantities of element released from the gilding groups were fewer than those from the control groups. The release of nickel and copper ions increased with the length of exposure significantly after three month of exposure. The element release from the control groups increased more rapidly than the gilding groups. The surface of the post-core in the control groups were all oxygenized while those in the gilding groups had been oxygenized only near the margins of the cores and the upper 1/3 part of the post with uncontinuous and relatively thin layers., Conclusion: Gilding surface treatment can decrease the release of nickel and copper ions from copper based-alloy post-core and the surface oxygenization, which will improve the biocompatibility of the core.

Objective: To assess the effect of the thickness of periodontal ligament on the fracture resistance of root and post-core system., Methods: Forty-five simulated roots in the same length, taper and diameter were made of polymethacrylate (PMMA). Then the wax patterns of post-cores were cast. Soft lining material was used to simulated periodontal ligament. And each specimen was embedded in acrylic resin and then fixed in a special jig on the universal load-testing machine. A compressive load was applied at a 90-degree angle to the long axis of the core until fracture, at a crosshead speed of 1 mm/min. The maximum of load and the displacement were recorded., Results: The mean values of load in root and post-core system were 148.033 N, 161.889 N, 168.667 N, 181.589 N, 194.622 N, and the mean values of displacement were 1.965 mm, 2.837 mm, 3.327 mm, 3.927 mm, 5.326 mm., Conclusion: The fracture resistance and displacement of root and post-core system with the same quality and altitude periodontal ligament are associated with the thickness of periodontal ligament when the range of thickness is from 0.2 mm to 1.0 mm.