Takahiro Yamashiro

Signaling Pathways Regulating IL-1α-induced COX-2 Expression

Interleukin-1α(IL-1α) stimulates the production of prostaglandin E2 (PGE2) in odontogenic keratocyst fibroblasts. However, the signaling pathways remain obscure. In this study, we investigated IL-1αsignaling pathways that regulate cyclooxygenase-2 (COX-2) expression in odontogenic keratocyst fibroblasts. IL-1αincreased the expression of COX-2 mRNA and protein, and PGE2 secretion in the fibroblasts. IL-1αincreased the phosphorylation of extracellular signal-regulated protein kinase-1/2 (ERK1/2), p38 mitogen-activated protein kinase (MAPK), and c-Jun N-terminal kinase (JNK). PD-98059, SB-203580, SP-600125, and PDTC—which are inhibitors of ERK1/2, p38, JNK, and nuclear factor-κB (NF-κB), respectively—attenuated the IL-1α-induced COX-2 mRNA expression and activated protein kinase C PGE2 secretion. IL-1α(PKC), and PKC inhibitor staurosporine inhibited IL-1α-induced phosphorylation of ERK1/2, p38, and JNK, and decreased IL-1α-induced COX-2 mRNA expression. Thus, in odontogenic keratocyst fibroblasts, IL-1αmay stimulate COX-2 expression both through the PKC-dependent activation of ERK1/2, p38, and JNK signaling pathways, and through the NF-κB cascade.

Effects of Positive Pressure in Odontogenic Keratocysts

Intracystic fluid pressure is thought to be involved in odontogenic cyst growth. In this study, we investigated the effects of positive pressure on the expression of interleukin-1α (IL-1α), matrix metalloproteinases (MMPs), and prostaglandin E2 (PGE2) in odontogenic keratocysts to determine whether this pressure stimulates inflammatory cytokine production and signaling of osteoclastogenic events. Positive pressure enhanced the expression of IL-1α mRNA and protein in odontogenic keratocyst epithelial cells, and increased the secretion of MMP-1, MMP-2, MMP-3, and PGE2 in a co-culture of odontogenic keratocyst fibroblasts and the epithelial cells. The pressure-induced secretions were inhibited by an interleukin-1 receptor antagonist. Recombinant human interleukin-1α (rhIL-1α) increased the secretion of MMP-1, MMP-2, MMP-3, and PGE2 in the fibroblasts. Furthermore, in the fibroblasts, rhIL-1α enhanced the expression of macrophage colony-stimulating factor (M-CSF) mRNA, and rhIL-1α-induced PGE2 increased the expression of nuclear factor κB ligand (RANKL) mRNA. Thus, positive pressure may play a crucial role in odontogenic keratocyst growth via stimulating the expression of IL-1α in epithelial cells.

Marsupialisation for keratocystic odontogenic tumours in the mandible: longitudinal image analysis of tumour size using 3D visualised CT scans

The purpose of this study was to determine how keratocystic odontogenic tumours (KCOTs) in the mandible are reduced during marsupialisation, and to predict the best time for secondary enucleation by analysing computed tomography (CT) images. 15 patients with KCOTs were treated with marsupialisation surgery, and 42 series of CT data taken during the marsupialisation process were analysed. CT data were reconstructed in three-dimensional (3D) images. The 3D images were used to measure the diameter and volume, and to analyse the changes that occurred after marsupialisation. Marsupialised KCOTs tended to be reduced equally towards the window in the tumour. The amount of volume reduction per day (V(r)) was reduced in proportion to the volume (V) with the formula V(r)=-0.0029×V. The formula manipulation for V was V=V(0)×e(-0.0029t) (t=duration after marsupialisaton (day)). The volume of marsupialised KCOTs was reduced by half over a 239 day cycle. These results demonstrate that the future shape of marsupialised mandibular KCOTs, under good control, could be predicted with significant accuracy using CT data. This prediction could decrease the prolonged marsupialisation state in patients with KCOTs.

Eruption prediction of mandibular premolars associated with dentigerous cysts.

OBJECTIVE A tooth with a dentigerous cyst (DC) does not always erupt by marsupialization. The eruption duration and conditions of DC-associated premolars were examined to predict such eruption following marsupialization. STUDY DESIGN The eruption and conditions including depth, root formation, inclination, and eruption space were examined retrospectively in 21 DC-associated mandibular premolars using dental and panoramic radiograms. RESULTS Fifteen of 21 premolars erupted half within 3 months and all 15 erupted completely within 10 months after marsupialization, without orthodontic traction. The age of the patients, tooth depth, and inclination were significantly different between the erupted and non-erupted groups, whereas there was no significant difference in the root formation or the eruption space between the 2 groups. CONCLUSIONS The successful eruption of a DC-associated premolar can be predicted within 3 months after marsupialization. Furthermore, the eruption may be affected by the patients age, tooth depth, and tooth inclination.

Optode for 2-phenethylamine using calixarene as host molecule

Abstract Calixarene ethoxycarbonyl ester is synthesized and used as a host molecule in optical detection of 2-phenethylamine. A plasticized poly(vinyl chloride) membrane containing the calixarene and a flourescent dye responds to 2-phenethylamine reversibly, and the sensitivity of an optode is increased by substitution of the ethoxycarbonyl ester for a hydroxy group in calixarene. However, a large interference response to pH is observed when the membrane contains calixarene. A phenolic proton is dissociated with an increase of pH, and fluorescence from the membrane is quenched by deprotonated calixarene, which causes the interference response to pH. The guest molecule of 2-phenethylamine is incorporated inside the calixarene, and the proton dissociation in calixarene occurs upon complexation. It results in the optode response to the guest molecule. The response to alkyl ammonium ions is also investigated, and the selectivity of the optide is discussed.

Advanced technique in fiber optic sensors

There are a lot of optical sensors for the selective determination of ion species. Some organic compounds also have been determined by optical sensors using the enzymatic and immunological reactions. On the other hand, calixarenes are well known as novel host molecules, and specific guest ions or molecules can be incorporated inside the cavity of calixarenes. This specific recognition function of calixarene has been applied to the development of electrochemical and optical ion sensors. However, an optical sensing of organic molecules using this host-guest system is a new approach at present. In this study, a sensing membrane containing a fluorescent probe and a calixarene derivative is prepared, and it is attached on a distal end of an optical fiber. An organic compound, which specially interacts with the calixarene derivative, is optically determined. The response mechanism of the sensor is discussed.