Effect of phorbol ester on K+ channel in an G292 osteoblast-like cell / 대한치과교정학회지

In order to investigate the action mechanism of protein kinase C on K+ channel in osteoblastic cell, effects of phorbol 12,13-dibutyrate on human osteoblast-like cells (G292) were studied by patch clamp technique with cell-attached configuration. In this experiment, 45pS ion channel was dominant in G292 cell line according to their approximate conductances in symmetrical 140mM KCl saline at holding potential of 60mV. In current-voltage relationship, reversal potential was 5.5mV at the condition of potassium enriched saline in the pipette and -27 mV at the condition of standard extracellular saline in the pipette. Phorbol 12, 13-dibutyrate 10 nM increased the open probability of 45 pS channel and staurosporine, an inhibitor of protein kinase C, suppressed this effect. Phorbol 12,13-dibutyrate moved the reversal potential of 45pS channel to more negative potential and increased the single channel current at the same membrame potential. In order to check the activation of protein kinase C in G292 cell by phorbol 12,13-dibutyrate, western blot of protein kinase C was performed. Phorbol 12,13-dibutyrate 0.1 micrometer translocated protein kinase C from cellular compartment to membrane compartment of the cell. These findings suggest that phorbol 12,13-dibutyrate, one of phorbol esters, activate 45pS channel in G292 cell and affect cell membrane potential, that regulate cellular function.

The correlation between dental compensation and craniofacial morphology in skeletal Class III malocclusion / 대한치과교정학회지

This investigation was designed to analyze the degree of dental compensation according to horizontal components of craniofacial skeleton and to investigate correlation between dental compensation and craniofacial pattern in skeletal class III malocclusion. The material selected for this study consisted of standard lateral cephalogram of 59 subjects in normal occlusion group, 91 subjects in mild skeletal class III malocclusion group and 58 subjects in severe skeletal class III malocclusion group. The mild skeletal class III malocclusion group was divided into two groups, one was class III malocclusion without anterior crossbite group and the other was class III malocclusion with anterior crossbite group. The data were analyzed by Quick-ceph image program. The results were as follows. 1. Mild skeletal class III malocclusion without anterior crossbite group showed the most labial inclination of upper incisors, followed by severe skeletal class III malocclusion group and mild skeletal class III malocclusion with anterior crossbite group, the Latter showing the least. The amount of lingual inclination of lower incisors was the largest in severe skeletal class III malocclusion group, and there was no statistically significant difference between mild skeletal claw III malocclusion without anterior crossbite group and mild skeletal class III malocclusion with anterior crossbite group. 2. There were little differences in vertical skeletal structure between mild skeletal class III malocclusion without anterior crossbite group and mild skeletal class III malocclusion with anterior cwssbite group, they showed statistically significant differences in the upper incisors measurements. 3. The measurements of lower incisors in mild skeletal class III malocclusion without anterior crossbite group and upper incisors in mild skeletal class III malocclusion with anterior crossbite group represented a high correlation with skeletal structure. Especially, deltaIMPA and deltaFMIA of lower incisor measurements, and deltaU1-FR deltaUi-SN of upper incisor measurements showed high correlation with skeletal structure in each group. 4. deltaIMPA and deltaFMIA of lower incisor measurements showed high correlation with skeletal structure in all groups. deltaUI-FH, deltaU1-SN and Ui-facial plane(mm) of upper incisor measurements represented higher correlation with skeletal structure than any other upper incisor measurements.