BACKGROUND: Death-associated protein kinase (DAPK) is a Ca2+/calmodulin-regulated Ser/Thr kinase which is involved in apoptosis. The aberrant methylation of its promoter region CpG islands may be one of the important ...BACKGROUND: Death-associated protein kinase (DAPK) is a Ca2+/calmodulin-regulated Ser/Thr kinase which is involved in apoptosis. The aberrant methylation of its promoter region CpG islands may be one of the important mechanisms of carcinogenesis. We studied the relationship of methylation status and expression of the DAPK gene with the clinical findings in cholangiocarcinoma. METHODS: Target DNA was modified by sodium bisulfite, coverting all unmethylated, but not methylated, cytosines to uracil, and subsequently detected by methylation-specific PCR. Moreover, mRNA expression of the DAPK gene was assessed by RT-PCR. RESULTS: Aberrant methylation of the DAPK gene was detected in 11 (30.6%) of 36 tissue specimens of cholangiocarcinoma, and in 2 (5.6%) of 36 specimens of adjacent normal tissues. DAPK mRNA was not expressed in tumor and adjacent tissues with hypermethylation of the DAPK promoter. There were no statistical differences in the extent of differentiation and invasion, lymph node metastasis or pathologic type between the methylated and unmethylated tissues. CONCLUSIONS: The frequency of DAPK gene methylation in cholangiocarcinoma is high and it may offer an effective means for earlier auxiliary diagnosis of the malignancy. The DAPK gene is probably suppressed by methylation, and it could become resistant to apoptosis and immunological surveillance. The DAPK gene epigenetically affected by methylation may be associated with the carcinogenesis of cholangiocarcinoma.展开更多
The influence of the delocalization probability on the mixing interaction between excited levels of Ce3+ and the conduction band of SrS was analysed. The observation of emission wave forms of SrSCe thin film electrolu...The influence of the delocalization probability on the mixing interaction between excited levels of Ce3+ and the conduction band of SrS was analysed. The observation of emission wave forms of SrSCe thin film electroluminescence showed that only leading edge emission peak was observed for one sample and the leading and trailing edge emission peaks were observed for another in a half period of sinusoid applied voltage. This difference is related to the influences of sulphur vacancies on the excitation and emission processes. The leading edge emssion is dominated by discrete luminescence caused by direct impact excitation and the trailing edge emission and a part of leading edge emission belong to recombination luminescence caused by impact ionization and delocalization.展开更多
A polynuclear complex containing a monomer of Cu(Ⅱ)-Zn(Ⅱ) heterobinuclear unit was synthesized and characterized by IR spectra and magnetic moment. The crystal and molecular structure of the complex, CuZnC_(19)H_(24...A polynuclear complex containing a monomer of Cu(Ⅱ)-Zn(Ⅱ) heterobinuclear unit was synthesized and characterized by IR spectra and magnetic moment. The crystal and molecular structure of the complex, CuZnC_(19)H_(24)Cl_4N_2O_2, was determined by X-ray diffraction, it crystallized in monoclinic, P2_1 / m, a = 8.812 (2), b = 15.972(3), c = 8.831(1) A, β = 114.33(1)°, V = 1132.4A^3, Z=2, D_c= 1.710 g / cm^3, λ(Mo K_α) = 0.71073A, μ = 25.227 cm^(-1), R = 0.051. R_w = 0.063 for 1130 ob- served reflections with I> 3σ(I) . The coordinated octahedra of Cu(Ⅱ) and tetrahedra of Zn(Ⅱ) via bridging Cl atoms form a single chain polynuclear complex. The Cu, Zn and bridging Cl atoms are located on the crystallographic symmetry plane m which is perpendicular to 2N and 2O donor plane.展开更多
基金The study was supported by a grant from the Provincial Outstanding Youth Foundation of Shandong, China (No. 2005BS02008).
文摘BACKGROUND: Death-associated protein kinase (DAPK) is a Ca2+/calmodulin-regulated Ser/Thr kinase which is involved in apoptosis. The aberrant methylation of its promoter region CpG islands may be one of the important mechanisms of carcinogenesis. We studied the relationship of methylation status and expression of the DAPK gene with the clinical findings in cholangiocarcinoma. METHODS: Target DNA was modified by sodium bisulfite, coverting all unmethylated, but not methylated, cytosines to uracil, and subsequently detected by methylation-specific PCR. Moreover, mRNA expression of the DAPK gene was assessed by RT-PCR. RESULTS: Aberrant methylation of the DAPK gene was detected in 11 (30.6%) of 36 tissue specimens of cholangiocarcinoma, and in 2 (5.6%) of 36 specimens of adjacent normal tissues. DAPK mRNA was not expressed in tumor and adjacent tissues with hypermethylation of the DAPK promoter. There were no statistical differences in the extent of differentiation and invasion, lymph node metastasis or pathologic type between the methylated and unmethylated tissues. CONCLUSIONS: The frequency of DAPK gene methylation in cholangiocarcinoma is high and it may offer an effective means for earlier auxiliary diagnosis of the malignancy. The DAPK gene is probably suppressed by methylation, and it could become resistant to apoptosis and immunological surveillance. The DAPK gene epigenetically affected by methylation may be associated with the carcinogenesis of cholangiocarcinoma.
文摘The influence of the delocalization probability on the mixing interaction between excited levels of Ce3+ and the conduction band of SrS was analysed. The observation of emission wave forms of SrSCe thin film electroluminescence showed that only leading edge emission peak was observed for one sample and the leading and trailing edge emission peaks were observed for another in a half period of sinusoid applied voltage. This difference is related to the influences of sulphur vacancies on the excitation and emission processes. The leading edge emssion is dominated by discrete luminescence caused by direct impact excitation and the trailing edge emission and a part of leading edge emission belong to recombination luminescence caused by impact ionization and delocalization.
文摘A polynuclear complex containing a monomer of Cu(Ⅱ)-Zn(Ⅱ) heterobinuclear unit was synthesized and characterized by IR spectra and magnetic moment. The crystal and molecular structure of the complex, CuZnC_(19)H_(24)Cl_4N_2O_2, was determined by X-ray diffraction, it crystallized in monoclinic, P2_1 / m, a = 8.812 (2), b = 15.972(3), c = 8.831(1) A, β = 114.33(1)°, V = 1132.4A^3, Z=2, D_c= 1.710 g / cm^3, λ(Mo K_α) = 0.71073A, μ = 25.227 cm^(-1), R = 0.051. R_w = 0.063 for 1130 ob- served reflections with I> 3σ(I) . The coordinated octahedra of Cu(Ⅱ) and tetrahedra of Zn(Ⅱ) via bridging Cl atoms form a single chain polynuclear complex. The Cu, Zn and bridging Cl atoms are located on the crystallographic symmetry plane m which is perpendicular to 2N and 2O donor plane.
