Takanori Shibata

BMP-2 release and dose-response studies in hydroxyapatite and β-tricalcium phosphate

The purpose of this study is to compare in vivo retention of BMP-2 and bone induction in HAp (porosity: 60-80%, pore size: 100-600 mum, sintering temperature: 800 degrees C, surface area: 1 m(2)/g) and beta-TCP (porosity: 75%, pore size: 100-400 mum, sintering temperature: 1050 degrees C, surface area: 4 m(2)/g). We estimated the in vivo release profile of (125)I-labeled BMP-2 and bone induction of hard tissues histologically. The amount of BMP-2 remaining in the beta-TCP at 1 day after implantation was 49.6%, while the amount was 34.0% in the HAp. Furthermore, the HAp and beta-TCP containing 0.0, 0.05, 0.1, 0.3, 0.5, 1.0, 5.0 microg of BMP-2 were implanted into the back subcutis of 4-week old Wistar rats. At 3 weeks after implantation, the ceramics were explanted and evaluated histologically. The HAp/BMP-2 (5.0 microg) system showed 3.0% in the total volume of bone at 3 weeks, while only in the beta-TCP/BMP-2 (5.0 microg) system showed 32.5%. These results indicate that the absorbable beta-TCP block may be an effective bioceramic for bone induction to deliver BMP-2 to the site of action.

Expression of Nerve Growth Factor and Neurturin, and Their Receptors in Mouse Taste Buds

Abstract Nerve growth factor (NGF) and neurturin (NTN) are neurotrophic factors that affect the proliferation and survival of neurons. Using a double immunostaining method, we examined whether the taste bud cells in the circumvallate, foliate and fungiform papillae of normal mice expressed NGF, NTN, and their receptors, TrkA and GFRα2, respectively, and if so, what type of cells in the taste buds expressed them. Because NCAM is reported to be expressed in type- III cells in the taste buds, PGP9.5 in type- III and some type- II cells, and α -gustducin, in some type- II cells, we used these markers to identify the types of taste bud cells. Almost all normal taste bud cells expressed NGF, TrkA, NTN, and GFRα2. Confocal laser scanning microscopic observations after double immunostaining showed that almost all anti-NCAM-, antiPGP9.5-, or anti- α -gustducin immunoreactive cells were positive for NGF. Thus, NGF-immunoreactive cells included type- II and - III cells, and perhaps type- I cells. Almost all anti-PGP9.5-immunoreactive cells were positive for TrkA, NTN, and GFRα2, revealing that type- III cells expressed TrkA, NTN, and GFRa2 ; although other types of cells were also immunopositive for these receptors and NTN. We suppose that NGF and NTN in the taste bud cells may exert trophic actions on the taste bud cells by binding to their respective receptors, and additionally be involved in the synaptic transmission from the type- III cells to the gustatory nerves.

Autogenous Demineralized Dentin Graft for Third Molar Socket Regeneration - A Case Report

The purpose of this case report is to evaluate the effects of a patient’s own demineralized dentin matrix (DDM) for socket preservation after extraction. A 27 year old male presented with slightly mesially inclined upper impacted right third molar with pericoronitis. Extraction of the impacted tooth was performed atraumatically and DDM granules were prepared from the extracted tooth. Firstly, the tooth was crushed by a newly developed auto-crush mill at 12,000 rpm for 60 seconds. The crushed granules were demineralized completely in 0.34 N nitric acid for 20 minutes and rinsed in distilled water. Immediate autograft of DDM was done into the tooth socket after 20 perforations into the socket surface. The results were evaluated clinically and radiographically at 3 and 12 months postoperatively. Dental X-ray just after the graft revealed radiopaque particles covering fully inside the socket. At 3 and 12 months of the follow-up, the socket appeared to be filled with uniform radiodense bone like tissue. The micro-CT and 3D micro-CT images at 12 months showed complete bone regeneration with no change in the vertical and horizontal dimension of the alveolar ridge. No significant difference was existed in radiodensity between new bone inside the socket and surrounding alveolar bone. The results of this case report suggest that autogenous DDM graft might be very effective as bone-forming materials for bone regeneration in the extracted socket.

Comparison of HAp and β-TCP in BMP-2 Dose-Response and Release Study

The aim of this study is to investigate in vivo local BMP-2 PK and bone induction in two bioceramics blocks (HAp, β-TCP), based on different composition and surface structures. We estimated the in vivo release profile of 125I–labeled BMP-2 and bone induction of hard tissues histologically. β-TCP is more effective for both BMP-2 retention and bone induction, compared to HAp, in the ectopic model.

Prevalence and dimensions of sella turcica bridging in Japanese female orthodontic patients

Abstract Purposes The purposes of this study were to examine the prevalence of sella turcica bridging; to evaluate age-related differences in sella turcica dimensions and the prevalence of sella turcica bridging; and to clarify the associations of sella turcica dimensions and bridging with maxillofacial skeletal patterns and dental anomalies, such as tooth agenesis and impaction, in Japanese female orthodontic patients. Materials and methods Lateral cephalograms and panoramic radiographs of 232 Japanese female orthodontic patients, aged 7–35 years, were examined. In addition to conventional cephalometric measurements, sella turcica diameter (STD), interclinoid distance (ICD), and degree of ICL calcification [(STD ICD) to STD ratio] were evaluated. Results Sella turcica bridging occurred in 5.6% of all subjects. The mean values of STD, ICD, and degree of ICL calcification were 9.8 mm, 3.9 mm, and 60.0%, respectively. STD and degree of ICL calcification were larger and ICD was smaller in the ≥19-year-old group than in the 7–12-year-old group. No significant difference in sella turcica dimension or bridging prevalence was found in the anteroposterior or vertical skeletal pattern. Subjects with tooth impaction showed shorter ICDs and greater degrees of ICL calcification than did those without tooth impaction. Conclusions The prevalence of sella turcica bridging was 5.6%, and STD, ICD and degree of ICL calcification increased with age, in Japanese female orthodontic patients. In addition, sella turcica morphology and bridging were associated with tooth impaction, but not with maxillofacial skeletal deviations.

Tumor Growth, Local Invasion, Micrometastasis, and Lymph Node Metastasis of Oral Squamous Cell Carcinoma Visualized in Live Tissue by Green Fluorescent Protein Expression

Abstract We report the in vitro establishment of a highly stable green fluorescent protein (GFP)-expressing transfectant of a highly-invasive human tongue squamous cell carcinoma (HTSCC) cell line, SAS-H1. The fluorescent cells permitted the visualization of tumor growth, local invasion, micrometastasis and cervical lymph node metastasis after submucosal injection into the tongues of nude mice. SAS-H1 cells were transfected with the pEGFP-N1 expression vector containing the GFP and neomycin resistance genes. Stable SAS-H1 clones expressing high levels of GFP were selected stepwise in vitro in levels of geneticin (G418) of up to 3,500 μg/ml. Subsequent early stages of local invasion and micrometastasis were visualized by GFP fluorescence in a primary tumor of the tongue. Furthermore, lymph node metastasis was confirmed for all of the orthotopic transplants in mice. However, no distant metastases, including those of lung and liver, were observed. Thus, this model should be useful for studying the metastatic process and for evaluating anti-metastasis agents in pre-clinical trials.