The objective of this study was to establish an X-ray radiographic evaluation method of regenerated bone by comparison of X-ray photograph, bone mineral content, and bone morphometry by microfocus X-ray CT in a bone regeneration model using an acidic gelatin disc (AGD) containing a sustained release basic fibroblast growth factor (bFGF) system. A defect 6 mm in diameter was made in the cranium of 36 Wistar rats aged 16 weeks (6 animals per group). bFGF (1.0 and 10.0 μg) and physiological saline (control) were added to AGD with a water content of 81.8 ± 0.2%, and the discs were implanted in the bone defects. The animals were sacrificed after 4 and 8 weeks, and evaluated. Regenerated bone was evaluated by X-ray photodensitometry using an aluminum step wedge and imaging plate JP) and based on the CT concentration (pixel concentration) and volume on microfocus X-ray CT. Photodensitometry showed that bFGF promoted bone regeneration with time in a concentration-dependent manner. Microfocus X-ray CT also detected similar changes in the pixel concentration in the regenerated region and the regenerated bone volume, clarifying that bFGF promoted bone regeneration. The relative aluminum concentration measured by photodensitometry and the pixel concentration measured by microfocus X-ray CT were correlated. It was revealed that microfocus X-ray CT can non-invasively evaluate regenerated bone, and is capable of quantitative and 3 -dimensional analyses. These findings suggested that microfocus X-ray CT is useful for the assessment of regenerated bone in the clinical application of regenerative medical methods.
To elucidate the effects of various chemical mediators, which are considered to appear in inflammation, on vascular smooth muscle, annular specimens of porcine lingual arterial smooth muscle were prepared, and divided into specimens denuded or undenuded of vascular endothelium. These specimens were attached to the thermostat incubator of an intracellular calcium ion concentration measurement unit, stimulated with 40 mM KCl, noradrenalin (NA), or U46619, followed by administration of acetylcholine (ACh) or bradykinin (BK), and the isometric contractile tension generated and fluorescence intensity ratio were simultaneously measured ; the following conclusions were drawn. 1. The inhibition by ACh or BK of NA-, high KCl-, or U46619-induced contraction was dependent on the presence of vascular endothelium, suggesting the involvement of a decreased [Ca^<2+>]_i concentration in the contraction inhibition. 2. It was suggested that the inhibition of high KCl-induced contraction by ACh or BK was weaker than that of receptor stimulation-induced contraction. 3. The administration of BK showed biphasic changes in U46619-induced contractile tension and [Ca^<2+>]_i.
To establish effective regenerative periodontal therapy, a two-dimensional quantitative assay for regenerated alveolar bone in rats was developed, and the regenerative activity of Emdogain^<(R)> (EMD) as well as collagen sponge (CLS) and acid-polyglycolic gelatin sponge (GEL) was evaluated. After anesthetization of a Wistar rat, alveolar bone defects were prepared at both palato-distal sides of the maxillary first molars. The biomaterial was topically applied to one defect, and the other quadrant defect without application was designated as a control. One to 8 weeks after application, the animals were sacrificed, and the new bone formation (NBF) on the bone samples was measured by a newly-developed two-dimensional scale. The NBFs were observed at Week 1 and then gradually increased in all sites. The NBF in EMD-applied sites at Week 1 was significantly lower, and those in GEL-applied sites at Weeks 4 and 5 were significantly higher than those in controls (all p<0.05). However, the regenerated bone densities assayed by X-ray micro-CT tomograms in EMD-applied sites were significantly higher than the control. The present findings indicate that the developed assay could be a useful method for evaluation of the regenerative activities of biomaterials, and that EMD could induce the regeneration of alveolar bone with relatively higher density.
To elucidate B cell activation induced by Porphyromonas gingivalis, the lipopolysaccharide (LPS)-induced B cell proliferation and tyrosine phosphorylation in B cells from C 3 H/HeN and LPS-hyporesponsive C 3 H/HeJ mice were examined. P. gingivalis LPS induced cell proliferation of both C 3 H/HeN and C 3 H/HeJ B cells, accompanied by the induction of tyrosine phosphorylation of selected proteins that included 25 kDa protein (p25). In contrast, Escherichia coli LPS activated only C 3 H/HeN B cells to proliferate and to induce tyrosine phosphorylation of p25. In order to characterize p25, P. gingivalis LPS-activated B cell lysates were separated by two-dimensional gel electrophoresis (2D-PAGE). Two out of 8 spots of the candidates of p25 separated by 2D-PAGE were identified as Ran (Ras-like nuclear protein) by peptide mass fingerprinting with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Western blotting analysis revealed that Ran existed as at least 4 spots in B cells with and without LPS stimulation. However, total amounts and the amount of the most acidic spot of Ran apparently increased by P. gingivalis LPS stimulation. These results suggested that quantitative alteration and tyrosine phosphorylation of Ran are involved in P. gingivalis LPS-induced B cell proliferation.
After investigating 430 teeth of 346 patients having infected root canals after restorative procedures in four private practices, the following conclusions were obtained. 1. Upper and lower first primary molars were most susceptible to infected root canals. Upper second primary molars had the lowest susceptibility to infected root canals among all primary molars. 2. The peak age for obtaining restorative treatments was youngest in upper primary central incisors and it was 2 years. The highest peak age was 4 years in upper second primary molars. 3. In either restoration, more than half of the cases were treated without pulp capping. 4. The peak age for incidence of infected root canals after restorations was 4 years in upper primary central incisors. In these restored teeth, the more distally teeth were located, the higher peak age was observed; therefore, the peak age for upper and lower second primary molars was 5 or 6 years. 5. The duration between receiving restorative procedures and incidence of infected root canals was mostly within 6 months in upper first primary molars. Nevertheless, in almost 50 % of the other primary teeth except for lower and upper second primary molars, infection of root canals occurred within 1 to 1.5 years. 6. One third of children having infected root canals after restorations had some systemic diseases. On the other hand, two thirds of children were uncooperative at the time of restorations. Above the results, it was revealed that deep caries requires pulp capping and close proximity to pulp should be taken into consideration during restoring teeth with thin tooth structure such as upper and lower first primary molars and upper primary central incisors. In such cases as treatments on uncooperative young children, it is suggested that provisional treatments should be performed first before providing final restorations.