Shinji Kito

Okadaic acid stimulates expression of Fas receptor and Fas ligand by activation of nuclear factor kappa-B in human oral squamous carcinoma cells

In the present study, we used western blot and RT-PCR analysis to examine the expression of proteins and mRNAs of Fas receptor and Fas ligand in human oral squamous carcinoma SCC-25 cells treated with okadaic acid. Treatment with okadaic acid enhanced the expression of proteins and mRNAs of both Fas receptor and Fas ligand in SCC-25 cells. The amount of IkappaB-alpha in whole cell lysates decreased, while the level of NF-kappaB in nucleus increased, in the okadaic acid-treated cells. Okadaic acid-treatment also alters the cellular localization of NF-kappaB, from cytoplasm to nuclei. To investigate the activation of NF-kappaB in okadaic acid-treated SCC-25 cells, we performed electrophoretic mobility gel shift assay using nuclear extracts and the consensus oligonucleotide for NF-kappaB DNA binding site. The binding of nuclear proteins to the oligonucleotide of NF-kappaB increased when the cells had been treated with 20 nM okadaic acid for 4 h. We transfected the cells with pFLF1, which has the promoter region of Fas receptor gene containing NF-kappaB binding site. A luciferase reporter gene assay demonstrated that the activity in the cells transfected with pFLF1 and treated with 20 nM okadaic acid increased in a time-dependent manner and that the activity was more than three-fold over that in the control cells. Our results suggest that NF-kappaB activated at early stages in the okadaic acid-treated SCC-25 cells stimulated the promoter activity of Fas receptor in the cells leading to the apoptotic death of these cells.

Significance of Frequency-Selective Fat Saturation T2-Weighted MR Images for the Detection of Bone Marrow Edema in the Mandibular Condyle

Abstract The objective of this study was to evaluate the utility of frequency-selective fat saturation (FS) T2-weighted images (T2WI) for the detection of bone marrow edema in the mandibular condyle. MR evidence of bone marrow abnormalities was examined on the set of FS T2WI and conventional T1WI or of conventional T2WI and T1WI in 200 patients with temporomandibular joint (TMJ) related pain. Other parameters studied were TMJ effusion, disk displacement categories, and cortical bone abnormalities. The detection rate and area of bone marrow edema by FS T2WI and T1WI were significantly greater than those assessed by conventional T2WI and T1WI. The correlation between bone marrow abnormalities on FS T2WI and T1WI and pain was significantly stronger than with conventional T2WI and T1WI. This study confirms that FS T2WI is useful for the detection of the “edema pattern” in the mandibular condylar associated with TMJ-related pain.