Effect of gastrin on invasiveness of human colon cancer cells / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To investigate the effect of gastrin on invasiveness of human colon cancer cells and the role of gastrin receptor-focal adhesion kinase (FAK) signal transduction pathway in this proess.</p><p><b>METHODS</b>pCR3.1/GR vector expressing gastrin receptor was transfected into a colorectal cancer cell line Colo320 with lipofectamine 2000, and screened by G418. The expression levels of gastrin receptor of the parental cell line Colo320 and the transfected cell line Colo320/GR were assayed by RT-PCR. On the other hand, antisense oligonucleotide of FAK was used to block its expression. The mock transfected Colo320 and sense oligonucleotide Colo320 cells were used as controls. Colo320 and Colo320/GR cells were treated with increasing doses (0 approximately 100 nmol/L) of gastrin. Invasiveness of Colo320 and Colo320/GR cells was determined by Boyden chamber. Phosphorylation of focal adhesion kinase (FAK) tyr-397 was examined by immunoprecipitation and Western-blot.</p><p><b>RESULTS</b>RT-PCR results showed that the Colo320/GR cells had an mRNA level four times as high as that of Colo320 cells. Western blot showed that FAK tyr397 phosphorylation of Colo320 cells was apparently decreased. Colo320 and Colo320/GR cells showed a dose-dependent response to gastrin on invasiveness and phosphorylation of FAK tyr-397. Invasiveness of Colo320 cells reached its climax when concentration of gastrin was 100 nmol/L, and FAK tyr-397 phosphorylation was marked when concentration of gastrin was 10 nmol/L, but the latter decreased when gastrin concentration was increased to 100 nmol/L. Colo320/GR cells had the same tendency as Colo320 cells, but showed an even stronger invasiveness and a higher level of FAK tyr-397 phosphorylation than Colo320 cells. Before gastrin stimulation, the invasiveness of Colo320 cells transfected with antisense oligonucleotides and the controls showed no difference. After gastrin stimulation, the increase in invasiveness was much less than that in the controls.</p><p><b>CONCLUSION</b>Gastrin can evidently promote invasiveness of Colo320 cells via gastrin-gastrin receptor-FAK signal transduction pathway.</p>

The comparative study of the scanning parameters for diffusion tensor imaging of cervical cord / 中华放射学杂志

Objective To investigate the optimal scanning parameters for diffusion tensor imaging of the cervical cord.Methods MRI and diffusion tensor imaging of the cervical cord was performed in 80 healthy adult volunteers.Different parameters including b values,the number of the diffusion sensitive gradient directions,the number of excitations,and slice thickness were applied and their effects on the quality of the images were compared.DTI was performed on the cervical spinal cord with different b-values (400,700,and 1000 s/mm~2)in group 1,with different numbers of diffusion gradient directions(6,13, and 25)in group 2,with different numbers of excitations(2,4,and 8)in group 3,and with different slice thicknesses(2,3,and 4 mm)in group 4.Two radiology experts gave a score to every image with double blind methods,then compared the image quality.Results In the comparison of the four different parameters,DTIs using a b value of 700 s/mm~2(2.25?0.58)showed better image quality than those with the b values of 400 s/mm~2(1.86?0.53)and 1000 s/mm~2(1.48?0.35)(P