Localization of SUMOylation factors and Osterix in odontoblast lineage cells during dentin formation and regeneration.

Small ubiquitin-related modifier (SUMO) conjugation (SUMOylation) is a post-translational modification involved in various cellular processes including the regulation of transcription factors. In this study, to analyze the involvement of SUMOylation in odontoblast differentiation, we examined the immunohistochemical localization of SUMO-1, SUMO-2/3, and Osterix during rat tooth development. At the bud and cap stages, localization of SUMOs and Osterix was hardly detected in the dental mesenchyme. At the bell stage, odontoblasts just beginning dentin matrix secretion and preodontoblasts near these odontoblasts showed intense immunoreactivity for these molecules. However, after the root-formation stage, these immunoreactivities in the odontoblasts decreased in intensity. Next, to examine whether the SUMOylation participates in dentin regeneration, we evaluated the distribution of SUMOs and Osterix in the dental pulp after cavity preparation. In the coronal pulp chamber of an untreated rat molar, odontoblasts and pulp cells showed no immunoreactivity. At 4 days after cavity preparation, positive cells for SUMOs and Osterix appeared on the surface of the dentin beneath the cavity. Odontoblast-like cells forming reparative dentin were immunopositive for SUMOs and Osterix at 1 week, whereas these immunoreactivities disappeared after 8 weeks. Additionally, we further analyzed the capacity of SUMO-1 to bind Osterix by performing an immunoprecipitation assay using C2C12 cells, and showed that Osterix could undergo SUMOylation. These results suggest that SUMOylation might regulate the transcriptional activity of Osterix in odontoblast lineage cells, and thus play important roles in odontoblast differentiation and regeneration.

Root canal system of the maxillary canine.

To better assess the efficacy of mechanical preparation of root canals, transparent specimens of 250 extracted maxillary canines were investigated for canal configuration, thickness and curvature of the root canal, condition of any accessory canals, and location of the apical foramen. Fewer than 40% of the specimens showed accessory canals that were mechanically impossible to clean. The majority of the lateral branches were small, greater than a #15 file, and none of the branches were larger than a #20 file. Although apical foramina located away from the apex were observed in 30% of the maxillary teeth, 96% of all apical foramina were within 0.5 mm of the apex. Data on the thickness of the root and main canal in the apical portion and curvature of the root canal suggest that, for adequate apical preparation, a #60 file must be able to reach the apical constriction.

Construction of database for three-dimensional human tooth models and its ability for education and research--Carious tooth models -.

To construct a human teeth database which is freely available to researchers and students, three-dimensional human tooth models were generated in a previous study, by means of micro-CT, from 35 human teeth extracted during orthodontic treatment. In this study, X-ray images of 55 extracted human teeth were acquired using three-dimensional micro-CT at a resolution of 50x50x50 microm, and then visualized using a numerical data visualization software. These carious tooth models provided insight into the morphology and progression of carious defects as well as a rare insight into the morphology of carious tooth pulp, therefore rendering them as a useful tool and efficient method for dental students' learning. Moreover, these three-dimensional models could be simultaneously observed and used by many students and researchers at any one time, which was a superior advantage than having only one actual tooth for learning and study by many.

Alveolar bone regeneration of subcutaneously transplanted rat molar.

Regeneration of alveolar bone is essential for periodontal treatment. Recently, cell replacement therapy has been focused on periodontal disease, but the source of the cells that regenerate alveolar bone is still uncertain. Therefore, to clarify the source of these bone-regenerating cells, we transplanted GFP-transgenic rat molars into the subcutaneous tissues of wild-type rats. Five days after transplantation, the tooth was surrounded by connective tissue containing many blood vessels. At 10 days, bone-like tissue was formed in the connective tissue between the branches of the bifurcated root. This hard tissue expanded to almost all of this bifurcation area without osseous ankylosis after 20 days. All osteoblast-like cells in the newly formed matrix were immunopositive for GFP. In addition, these cells and the peripheral cells of the matrix showed intense immunoreactivity for BMP4, Runx2, BSP, and OPN. These results demonstrate that periodontal ligament tissue contains osteoprogenitor cells that have the ability to regenerate alveolar bone. Our model suggests that these regeneration processes might be similar to normal alveolar bone formation.

Obstructive sleep apnea-hypopnea syndrome patients with overweight and hypertension in a Japanese workplace.

The objective of this study was to determine the relationship between obstructive sleep apnea-hypopnea syndrome (OSAHS) and overweight combined with hypertension and to examine whether OSAHS in conjunction with overweight and hypertension is associated with daytime sleepiness. In a Japanese workplace of 28,636 employees, 368 men (19-62 yr old), who were anxious regarding their OSAHS symptoms, underwent home pulse oximetry. Of these, 153 men subsequently underwent all-night polysomnography (PSG), and OSAHS was diagnosed in 149. We next classified these 149 men into the following groups: A [Overweight (-)/Hypertension (-), n=41], B [Overweight (-)/Hypertension (+), n=15], C [Overweight (+)/Hypertension (-), n=46], and D [Overweight (+)/Hypertension (+), n=47]. The Epworth Sleepiness Scale (ESS) was used to evaluate daytime sleepiness and the apnea-hypopnea index (AHI) was used to evaluate the severity of OSAHS. The averages of the ESS score and the AHI were compared in each group. Both the average ESS scores and the percentage of ESS scores > or =11 were not significantly different among the groups. The average AHI of group D was the highest among all of the groups and that of group C was significantly higher than those of groups A and B. In all the groups, the OSAHS patients with overweight and hypertension in this study had the highest AHI. The level of daytime sleepiness evaluated by the ESS in this study was almost the same in the OSAHS patients regardless of the degree of overweight or hypertension. These observations suggest that it is necessary to positively recommend PSG to men who are suspected of having OSAHS with overweight and hypertension, even if they do not have daytime sleepiness.

Immunohistochemical localization of alpha-Smooth muscle actin during rat molar tooth development.

The dental follicle contains mesenchymal cells that differentiate into osteoblasts, cementoblasts, and fibroblasts. However, the characteristics of these mesenchymal cells are still unknown. alpha-Smooth muscle actin (alpha-SMA) is known to localize in stem cells and precursor cells of various tissues. In the present study, to characterize the undifferentiated cells in the dental follicle, immunohistochemical localization of alpha-SMA was examined during rat molar tooth development. Rat mandibles were collected at embryonic days (E) 15-20 and postnatal days (P) 7-28. Immunohistochemical stainings for alpha-SMA, periostin, Runt-related transcription factor-2 (Runx2), tissue nonspecific alkaline phosphatase (TNAP), and bone sialoprotein (BSP) were carried out using paraffin-embedded sections. alpha-SMA localization was hardly detected in the bud and cap stages. At the early bell stage, alpha-SMA-positive cells were visible in the dental follicle around the cervical loop. At the late bell to early root formation stage (P14), these cells were detected throughout the dental follicle, but they were confined to the apical root area at P28. Double immunostaining for alpha-SMA and periostin demonstrated that alpha-SMA-positive cells localized to the outer side of periostin-positive area. Runx2-positive cells were visible in the alpha-SMA-positive region. TNAP-positive cells in the dental follicle localized nearer to alveolar bone than Runx2-positive cells. BSP was detected in osteoblasts as well as in alveolar bone matrix. These results demonstrate that alpha-SMA-positive cells localize on the alveolar bone side of the dental follicle and may play a role in alveolar bone formation.

A child with simple ulcer of the colon effectively treated with the combination of prednisolone, azathioprine, and pentoxifylline.

A rare case of simple ulcer of the colon in a 7-year-old girl is reported. Simple ulcer is clinically and pathologically recognized as a serious disease linked to intestinal Behcet's disease. Recently, some immunomodulators, such as thalidomide and antitumor necrosis factor monoclonal antibody, have been used to treat Behcet's disease, with varying degrees of success. Pentoxifylline (PTX) is also known to inhibit such inflammatory mediators as tumor necrosis factor-alpha, interleukin-1beta, and interleukin-6. In this present patient combination treatment with prednisolone, azathioprine, and PTX improved corticosteroid dependence palliatively and prevented further relapse during a follow-up period of more than 12 months, without serious side effects.