Institute for Frontier Oral Science

Yokosuka, Japan

Institute for Frontier Oral Science

Yokosuka, Japan

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Arany S.,University of Rochester | Ohtani S.,Institute for Frontier Oral Science
Forensic Science International | Year: 2011

This study describes an innovative application of a well-established method of age determination. The conventional method of aspartic acid racemization (AAR) is based on estimation of the d-l-aspartic acid ratio in slow turnover tissues, such as tooth tissue, to reflect the age of an individual. This method has been recently applied to age estimation in forensic investigations, and is also widely used for archeological dating of fossils. We suggest that the aspartic acid racemization method could be applied to a significant, although unresolved, forensic issue: that of bloodstain dating. Standard kinetic experiments were used to describe the characteristics of the racemization reaction in bloodstains, which were then employed to estimate the age of various samples. The soluble protein fraction of a bloodstain produced a stronger correlation between elapsed time and d-aspartic acid content than total amino acid fractions. According to our preliminary results, the time lapse after the creation of a bloodstain can be determined ex vivo by measuring the extent of aspartic acid racemization. Our analysis highlights the need for further study into the preservation and composition of bloodstains to assist in further development of this pioneering application. © 2011 Elsevier Ireland Ltd.


Yagihara K.,Saitama Cancer Center | Okabe S.,Saitama Cancer Center | Okabe S.,The Nippon Dental University | Ishii J.,Saitama Cancer Center | And 7 more authors.
International Journal of Oral and Maxillofacial Surgery | Year: 2013

The purpose of this study was to evaluate the stability and viability of mandibular bone regeneration using a poly(l-lactide) (PLLA) mesh and autogenous particulate cancellous bone and marrow (PCBM). Sixty-two procedures were undertaken at eight hospitals (22 malignant tumours, 30 benign tumours, five cysts, two osteomyelitis, two trauma, and one atrophy of the alveolar ridge); the success rate was 84%. The follow-up period was between 9 and 200 months (mean 88.2 months). Consequently, bone regeneration at 6 months postoperation was excellent in 35 cases (57%), good in 17 cases (27%), and poor in 10 cases (16%). In six of the 'poor' cases, the PLLA mesh was removed due to local infection early after surgery. Bone resorption > 20% was observed in only one of 46 cases with a follow-up term of >1 year. There were no signs of any other adverse effects except in one case where a section of the tray broke off late in the follow-up period. It is concluded that this method is stable and effective due to favourable morphological and functional recovery and low invasiveness. It may thus be a useful alternative procedure for mandibular reconstruction. © 2013 International Association of Oral and Maxillofacial Surgeons.


Okada Y.,Kanagawa Dental College | Hamada N.,Kanagawa Dental College | Kim Y.,Kanagawa Dental College | Takahashi Y.,Kanagawa Dental College | And 3 more authors.
Archives of Oral Biology | Year: 2010

Introduction: Periodontal disease is characterised by alveolar bone loss. Some studies have suggested the involvement of sympathetic nervous system in the deterioration of periodontal disease. Noradrenaline, released from sympathetic nerve terminals due to various stimuli, binds to specific adrenergic receptors on immune cells. Recently, we reported that restraint stress augmented the alveolar bone loss induced by Porphyromonas gingivalis infection. In this study, we investigated the effects of the β-blocker (propranolol) on alveolar bone loss induced by P. gingivalis infection to examine the involvement of sympathetic nerves in periodontal breakdown. Methods: Sprague-Dawley rats were treated as follows: saline injection (Group A), propranolol injection (Group B), saline injection and oral challenge with P. gingivalis (Group C), and propranolol injection and oral challenge with P. gingivalis (Group D). Horizontal alveolar bone loss was evaluated by measuring the distance between the cemento-enamel junction and the alveolar bone crest. Specimens from periodontal tissue were evaluated by staining with hematoxylin-eosin and tartrate-resistant acid phosphatase. Results: Blockade of β-receptors in periodontal tissue by propranolol inhibited osteoclast differentiation and prevented alveolar bone loss induced by P. gingivalis infection. Histological study revealed that the number of osteoclasts detected was proportional to the level of bone loss. Conclusions: These results indicate that the sympathetic nervous system is involved in the development of periodontitis and suggest that sympathetic signal modulation with β-blockers enables the control of alveolar bone mass metabolism. © 2010 Elsevier B.V. All rights reserved.


Matsumoto G.,Kanagawa Dental College | Matsumoto G.,Foundation for Biomedical Research and Innovation | Hoshino J.,Institute for Frontier Oral Science | Kinoshita Y.,Foundation for Biomedical Research and Innovation | And 5 more authors.
Journal of Biomaterials Applications | Year: 2012

The aim of this study was to evaluate the effects of combining porous poly-lactic acid-co-glycolic acid-co-ε-caprolactone (PLGC) as a barrier membrane and collagen sponge containing basic fibroblast growth factor (bFGF) to promote bone regeneration in the canine mandible. In six beagle dogs, two lateral bone defects per side were created in the mandible. The lateral bone defects on the left side were treated with a PLGC membrane plus a collagen sponge containing bFGF. In half of these, the collagen sponge contained 50 μg of bFGF. In the other half, it contained 250 μg of bFGF. As a control, we treated the right-side bone defects in each animal with the same PLGC membrane but with a collagen sponge containing phosphate buffered saline. Computed tomography (CT) images were recorded at 3 and 6 months post-op to evaluate regeneration of the bone defects. After a healing period of 6 months, whole mandibles were removed for micro-CT and histological analyses. The post-op CT images showed that more bone had formed at all experimental sites than at control sites. At 3 months post-op, the volume of bone at defect sites covered with PLGC membrane plus 250 μg of bFGF was significantly greater than it was at defect sites covered with PLGC membrane plus 50 μg of bFGF. At 6 months post-op, however, this difference was smaller and not statistically significant. Micro-CT measurement showed that the volume of new bone regenerated at bone-defect sites, covered with PLGC membrane plus bFGF, was significantly greater than that of control sites. However, the presence or absence of bFGF in the collagen sponge did not significantly affect the bone density of new bone. These results suggest that the macroporous bioresorbable PLGC membrane plus collagen sponge containing bFGF effectively facilitates healing in GBR procedures. © 2011 The Author(s).


Alkass K.,Karolinska Institutet | Buchholz B.A.,Lawrence Livermore National Laboratory | Ohtani S.,Institute for Frontier Oral Science | Yamamoto T.,Kanagawa Dental College | And 2 more authors.
Molecular and Cellular Proteomics | Year: 2010

Age determination of unknown human bodies is important in the setting of a crime investigation or a mass disaster because the age at death, birth date, and year of death as well as gender can guide investigators to the correct identity among a large number of possible matches. Traditional morphological methods used by anthropologists to determine age are often imprecise, whereas chemical analysis of tooth dentin, such as aspartic acid racemization, has shown reproducible and more precise results. In this study, we analyzed teeth from Swedish individuals using both aspartic acid racemization and radiocarbon methodologies. The rationale behind using radiocarbon analysis is that aboveground testing of nuclear weapons during the cold war (1955-1963) caused an extreme increase in global levels of carbon-14 (14C), which has been carefully recorded over time. Forty-four teeth from 41 individuals were analyzed using aspartic acid racemization analysis of tooth crown dentin or radiocarbon analysis of enamel, and 10 of these were split and subjected to both radiocarbon and racemization analysis. Combined analysis showed that the two methods correlated well (R2 = 0.66, p < 0.05). Radiocarbon analysis showed an excellent precision with an overall absolute error of 1.0 ± 0.6 years. Aspartic acid racemization also showed a good precision with an overall absolute error of 5.4 ± 4.2 years. Whereas radiocarbon analysis gives an estimated year of birth, racemization analysis indicates the chronological age of the individual at the time of death. We show how these methods in combination can also assist in the estimation of date of death of an unidentified victim. This strategy can be of significant assistance in forensic case-work involving dead victim identification. Molecular & Cellular Proteomics 9:1022-1030, 2010.


Arany S.,Akita University | Ohtani S.,Institute for Frontier Oral Science
Journal of Forensic Sciences | Year: 2010

Here, we report on an experimental approach of simultaneous determination of various amino acids racemization (AAR) rates in teeth. We evaluated the measurements of aspartic acid (Asp), glutamate (Glu), and alanine (Ala) isolated from dentin. Asx D/L rates from total amino acid fraction, generally used for age estimation, showed high correlation (r = 0.98) with age. As Glx and Ala showed very slow racemization kinetics in TA, we performed further analysis of the acid-soluble protein (SP) fraction. The results supported improved correlation between age and D/L rates for Glu (r = 0.84) and Ala (r = 0.85), as well as for Asp (r = 0.98). By providing further elucidation on dentin protein racemization, the technique offers a considerable opportunity to involve other amino acids in age estimation studies. As the process does not require additional separation steps, the method can be easily adapted to existing protocols. © 2010 American Academy of Forensic Sciences.


Yamamoto T.,Kanagawa Dental College | Ohtani S.,Institute for Frontier Oral Science
Methods in Molecular Biology | Year: 2012

Estimation of chronological age is essential in forensic and archeological science. The racemization method is one of the best methods to meet the demands of these scientific fields, providing both accuracy of the estimated age and simplicity of technique. In general, living organs are composed of l-form amino acids. Conversion from l-form to d-form amino acids is a first-order chemical reaction. Thus, the quantity of d-form amino acids in an organ is proportional to the passed time (age) after organ completion if no protein turnover occurs after organization. However, every living organ undergoes some degree of protein turnover. Therefore, organs with low metabolic rates, such as teeth and bone, should be targeted for the racemization method. The most critical point of the technique may be the complete separation of d-and l-forms by gas chromatography because of the very small amounts of d-form amino acids present. We describe the detailed procedures and the critical points for obtaining reliable estimated ages using the racemization method.


Ohtani S.,Institute for Frontier Oral Science | Yamamoto T.,Kanagawa Dental College
Journal of Forensic Sciences | Year: 2010

When an unidentified body is found, it is essential to establish the personal identity of the body in addition to investigating the cause of death. Identification is one of the most important functions of forensic dentistry. Fingerprint, dental, and DNA analysis can be used to accurately identify a body. However, if no information is available for identification, age estimation can contribute to the resolution of a case. The authors have been using aspartic acid racemization rates in dentin (D-aspartic acid/L-aspartic acid: D/L Asp) as an index for age estimation and have obtained satisfactory results. We report five cases of age estimation using the racemization method. In all five cases, estimated ages were accurate within a range ±3 years. We conclude that the racemization method is a reliable and practical method for estimating age. © 2010 American Academy of Forensic Sciences.


Ohtani S.,Institute for Frontier Oral Science | Yamamoto T.,Kanagawa Dental College
Journal of Forensic Sciences | Year: 2011

Racemization method is currently considered to be one of the most accurate methods for age estimation. There are many factors that affect racemization reaction velocities. We investigated ethnic differences in the racemization reaction velocities between Japanese and Scandinavian teeth. After a heating experiment, the Arrhenius equation was used to obtain a rate constant (k). Both groups presented almost identical velocities, indicating that there was no difference in the tooth racemization reaction between the two groups. However, because 14 of the 18 Scandinavian teeth had multiple roots, it is possible that accurate racemization rates of the teeth themselves were not reflected in the results. These findings reconfirm that the type of tooth selected is extremely important when evaluating age by racemization. © 2010 American Academy of Forensic Sciences.


PubMed | Institute for Frontier Oral Science
Type: Journal Article | Journal: Journal of forensic sciences | Year: 2011

Racemization method is currently considered to be one of the most accurate methods for age estimation. There are many factors that affect racemization reaction velocities. We investigated ethnic differences in the racemization reaction velocities between Japanese and Scandinavian teeth. After a heating experiment, the Arrhenius equation was used to obtain a rate constant (k). Both groups presented almost identical velocities, indicating that there was no difference in the tooth racemization reaction between the two groups. However, because 14 of the 18 Scandinavian teeth had multiple roots, it is possible that accurate racemization rates of the teeth themselves were not reflected in the results. These findings reconfirm that the type of tooth selected is extremely important when evaluating age by racemization.

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