Hiromasa Kawana

Keio University, Edo, Tōkyō, Japan

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Publications (39)56.76 Total impact

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    ABSTRACT: Human dental pulp stem/progenitor cells (hDPSCs) are attractive candidates for regenerative therapy because they can be easily expanded to generate colony-forming unit-fibroblasts (CFU-Fs) on plastic and the large cell numbers required for transplantation. However, isolation based on adherence to plastic inevitably changes the surface marker expression and biological properties of the cells. Consequently, little is currently known about the original phenotypes of tissue precursor cells that give rise to plastic-adherent CFU-Fs. To better understand the in vivo functions and translational therapeutic potential of hDPSCs and other stem cells, selective cell markers must be identified in the progenitor cells. Here, we identified a dental pulp tissue-specific cell population based on the expression profiles of 2 cell-surface markers LNGFR (CD271) and THY-1 (CD90). Prospectively isolated, dental pulp-derived LNGFR(Low+)THY-1(High+) cells represent a highly enriched population of clonogenic cells-notably, the isolated cells exhibited long-term proliferation and multilineage differentiation potential in vitro. The cells also expressed known mesenchymal cell markers and promoted new bone formation to heal critical-size calvarial defects in vivo. These findings suggest that LNGFR(Low+)THY-1(High+) dental pulp-derived cells provide an excellent source of material for bone regenerative strategies.
    Journal of dental research 10/2015; DOI:10.1177/0022034515610748 · 4.14 Impact Factor
  • H. Kawana · S. Usuda · K. Yu · T. Nakagawa · K. Ohnishi ·

    International Journal of Oral and Maxillofacial Surgery 10/2015; 44:e88-e89. DOI:10.1016/j.ijom.2015.08.628 · 1.57 Impact Factor
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    ABSTRACT: In any immediate reconstruction of the maxillofacial defect after total maxillectomy, the defect is often covered with a flap, however, dentures cannot be maintained stably by the flap, because of the high mobility and large amount of displacement of the flap under pressure. Therefore, we developed a method in which a muscle flap is transplanted without creating a skin island in the oral cavity and a denture is immediately fixed with titanium screws, and obtained favorable results.
  • K. Yu · S. Uozumi · K. Ohnishi · S. Usuda · H. Kawana · T. Nakagawa ·
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    ABSTRACT: Image navigation systems and robotics are leading technologies to improve the accuracy of dental surgery. In this paper, stereo vision based navigation system is implemented to the three degrees of freedom implant surgery assistant robot. The aim of this research is to achieve cooperative guide system for teaching the information of 'where to start cutting'. To achieve this aim, modulated potential field based on Lennard-Jones potential field is proposed for realizing following three requested performances. (1) Surgeon can freely operate the manipulator when it far from the destination. (2) The manipulator will apply adjusting force to converge correctly when approaching to the destination. (3) The manipulator will apply adjusting force for collision avoidance when passing the destination. This paper uses stereo camera to detect the destination. The validity of the proposed method is confirmed through experiment using three degrees of freedom parallel link manipulator.
  • H Miyashita · H Shiba · H Kawana · T Nakahara ·
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    ABSTRACT: In recent years, proactive surgical treatment has been reported to be effective for medication-related osteonecrosis of the jaw (MRONJ). However, an uncertain resection entails the risk of recurrence, whereas an extensive surgical procedure may lead to a marked reduction in quality of life as a result of reduced masticatory function and poor cosmesis. Therefore, radiological assessment can be helpful to accurately localize MRONJ before surgery. The integrated single-photon emission computed tomography and computed tomography system (SPECT/CT) allows oral and maxillofacial surgeons to identify an area of MRONJ, especially when three-dimensional (3D) SPECT and CT fusion images are offered. A patient for whom 3D SPECT and CT image fusion (as developed in the radiology department of the study institution) contributed to determining the extent of the lesion, thereby leading to a favourable patient prognosis, is reported herein. There was exact correlation between the histological and radiological results. Copyright © 2015 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.
    International Journal of Oral and Maxillofacial Surgery 05/2015; 44(9). DOI:10.1016/j.ijom.2015.05.002 · 1.57 Impact Factor
  • K. Yu · T. Nakano · K. Ohnishi · S. Usuda · T. Nakagawa · H. Kawana ·
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    ABSTRACT: Image processing and robotics are leading technologies to improve dental surgery. The important information for physicians to perform implant surgery is 'where to start cutting' and 'when to stop cutting'. The aim of this research is to achieve automatic guide system for teaching the information of 'where to start cutting'. To achieve this aim, L-J potential field, which can realize required performance of position adjustment with human interaction are proposed in this paper. Proposed potential field has three features. First, physician can free moving the manipulator when far from the distinction. Second, the manipulator will apply adjusting force for correctly converges to the destination when approaching to the distinction. Third, the manipulator will apply adjusting force for collision avoidance when passing the distinction. The validity of proposed L-J potential are confirmed through experiment using 2DOF parallel link manipulator.

  • Nippon Koku Geka Gakkai zasshi 01/2015; 61(4):246-250. DOI:10.5794/jjoms.61.246
  • R. Iwasaki · T. Miyamoto · M. Morita · T. Mori · T. Nakagawa · H. Kawana ·

  • S. Usuda · K. Ohnishi · K. Yu · T. Nakagawa · H. Kawana ·

    Journal of Oral and Maxillofacial Surgery 09/2014; 72(9):e61. DOI:10.1016/j.joms.2014.06.105 · 1.43 Impact Factor
  • Koyo Yu · Sho Iwata · Kouhei Ohnishi · Shin Usuda · Taneaki Nakagawa · Hiromasa Kawana ·
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    ABSTRACT: Since uncontrolled force can cause drill-bit break-age, excessive heat generation, and bone damage, prediction of the drilling force is important parts to increase success rate of implant operations. This paper presents a vibration model for prediction of the drilling vibration. The force from the drill is modeled by considering variation in force caused by CT value and feed velocity change. This method can be applied for a cutting force presentation method using haptic drilling system. This system allows dental students to learn procedures such as cutting the jaw bone. It can also be used for prior confirmation before implant surgery because doctor can experience the force response. The advantages of this system are the high force output quality and fine position sensing quality. The validity of the proposed method was confirmed through experiments using pine wood mentioned in Misch's bone density classification.
    2014 IEEE 13th International Workshop on Advanced Motion Control (AMC); 03/2014
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    ABSTRACT: Paraneoplastic pemphigus (PNP) is an autoimmune mucocutaneous blistering disease that occurs in association with underlying neoplasms. We report a case of orally-initiated PNP associated with thymoma. A 51-year-old man presented with erosive stomatitis affecting the floor of the mouth, buccal region, and soft palate mucosa. These lesions rapidly deteriorated, and Nikolsky phenomena with lichenoid changes was noted. A histological examination showed suprabasilar acantholysis with cell infiltration in the lamina propria. Direct immunofluorescence showed positivity for IgG and C3 in the intercellular spaces of the squamous epithelia. Indirect immunofluorescence showed IgG bound to the epithelium of the rat bladder. In addition, the patient serum reacted against 210 and 190 kDa proteins on immunoblotting. On computed tomography, a thymoma was detected in the anterior mediastinum. The patient showed severe oral blistering associated with thymoma and was finally given a diagnosis of PNP. Despite surgical excision of the thymoma, the oral symptoms persisted. To achieve remission, steroid pulse therapy, intravenous immunoglobulin therapy, cyclosporine treatment and plasma apheresis were additionally performed. We have been carefully following the activity of the oral symptoms and thymoma for 12 years. The characteristics leading to early diagnosis, including the clinical symptoms, serological test results, and diagnostic criteria of PNP, are discussed.
    Nippon Koku Geka Gakkai zasshi 01/2014; 60(5):272-276. DOI:10.5794/jjoms.60.272
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    ABSTRACT: Chronic inflammation is frequently associated with tumorigenesis in elderly people. By contrast, young people without chronic inflammation often develop tumors considered independent of chronic inflammation but driven instead by mutations. Thus, whether inflammation has a significant role in tumor progression in tumors driven by mutations remains largely unknown. Here we show that TNFα is required for the tumorigenesis of osteosarcoma, the most common tumor in children and adolescents. We show that transplantation of AX osteosarcoma cells, which harbor mutations driving c-Myc overexpression and Ink4a-deficiency, in wild-type mice promotes lethal tumorigenesis accompanied by ectopic bone formation and multiple metastases, phenotypes seen in osteosarcoma patients. Such tumorigenesis was completely abrogated in TNFα-deficient mice. AX cells have the capacity to undergo osteoblastic differentiation; however, that activity was significantly inhibited by TNFα treatment, suggesting that TNFα maintains AX cells in an undifferentiated state. TNFα inhibition of AX cell osteoblastic differentiation occurred through ERK activation, and a pharmacological TNFα inhibitor effectively inhibited both AX cell tumorigenesis and increased osteoblastic gene expression and increased survival of tumor-bearing mice. Lethal tumorigenesis of AX cells was also abrogated in IL-1α/IL-1β doubly deficient mice. We found that both TNFα and IL-1 maintained AX cells in an undifferentiated state via ERK activation. Thus, inflammatory cytokines are required to promote tumorigenesis even in mutation-induced tumors, and TNFα/IL-1 and ERK may represent therapeutic targets for osteosarcoma.Oncogene advance online publication, 16 December 2013; doi:10.1038/onc.2013.545.
    Oncogene 12/2013; 33(33). DOI:10.1038/onc.2013.545 · 8.46 Impact Factor
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    ABSTRACT: We report a case of auricular malformation treated by placement of an osseointegrated implant-supported epithesis using telenavigation and model simulation. A 66-year-old male suffering from auricular malformation and atresia auris of his right ear since birth visited our department in October 2006. The patient desired placement of an ear epithesis supported by osseointegrated implants. Computed tomographic (CT) scans were obtained for use in the navigation system as a prerequisite for the telenavigation and the operative plan was designed in consultation with an overseas oral and maxillofacial surgeon having rich experience in telenavigation surgery. We also constructed a preoperative simulation model and a mirror model of the unaffected left ear based on laser lithography to produce successful operation and symmetrical form of a symmetrical ear epithesis as contrast with identical to that on the left side. The osseointegrated implant surgery was carried out under telenavigation guidance. As a result, safe and accurate positioning of the implants was achieved and a symmetrical and elaborate epithesis could be fabricated.
    09/2013; 27(1). DOI:10.1016/j.ajoms.2013.07.007
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    ABSTRACT: Objectives: Human dental pulp stem cells (hDPSC) are an attractive option for regenerative therapy, as the tissue of origin (dental pulp) is readily available and the cells are easy to expand to the required numbers for generating graft material. Traditionally however, hDPSC isolated based on their adherence to plastic, frequently contain contaminating cells, which has limited our ability to investigate their basic biology. In the present study, we identify specific cell surface markers for the prospective isolation of highly purified hDPSC. Methods: We previously demonstrated that LNGFR and Thy-1 could be used to prospectively isolate a pure population of mesenchymal stem cells (MSCs) from human bone marrow (hBM). Using flow cytometry we examine if these markers may be used to identify a pure population of hDPSC. Using this sub-population of hDPSC, we then evaluated their expression pattern of cell surface markers, proliferative and differentiation potential. To examine bone regeneration and neovascularization, these cells were transplanted into mouse skull in vivo imaging was perfomed through a cranial window. Results: LNGFR (low+) /Thy-1 (high+) hDPSC have higher colony-forming unit fibroblast (CFU-F) frequency compared to LNGFR (+) /Thy-1 (low+) hDPSC. These cells also have high proliferative potential in vitro and demonstrated wound healing capacity when transplanted in vivo. Conclusions: In this study, we demonstrate that surface expression of LNGFR and Thy-1 can be used to prospectively isolate purified hDPSC cell populations. This information is critical if hDPSC are to be used effectively in future regenerative therapies.
    IADR/AADR/CADR General Session and Exhibition 2013; 03/2013
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    ABSTRACT: The targeting of antioxidant systems that allow stem-like cancer cells to avoid the adverse consequences of oxidative stress might be expected to improve the efficacy of cancer treatment. Here we show that head and neck squamous cell carcinoma (HNSCC) cells that express variant isoforms of CD44 (CD44v) rely on the activity of the cystine transporter subunit xCT for control of their redox status. xCT inhibition selectively induces apoptosis in CD44v-expressing tumor cells without affecting CD44v-negative differentiated cells in the same tumor. In contrast to CD44v-expressing undifferentiated cells, CD44v-negative differentiated cells manifest epidermal growth factor receptor (EGFR) activation and rely on EGFR activity for their survival. Combined treatment with inhibitors of xCT-dependent cystine transport and of EGFR resulted in a synergistic reduction of EGFR-expressing HNSCC tumor growth. Thus, xCT-targeted therapy may deplete CD44v-expressing undifferentiated HNSCC cells and concurrently sensitize the remaining differentiating cells to available treatments including EGFR-targeted therapy.
    Cancer Research 01/2013; 73(6). DOI:10.1158/0008-5472.CAN-12-3609-T · 9.33 Impact Factor
  • Koyo Yu · Yuki Saito · Yusuke Kasahara · Hiromasa Kawana · Shin Usuda · Kouhei Ohnishi ·
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    ABSTRACT: It is important to classify the bone density for dental implants. In this paper, a method for estimating the bone density is proposed by modeling the relationship between the cutting force and the bone density. The bone density can be obtained in real time by comparing the force from a reaction force observer with the force from a thrust force formula with pre-estimated bone density parameters. The validity of the proposed method was confirmed through experiments using different types of wood mentioned in Misch's bone density classification. The experimental results indicated that the error of contact detection was +50 μm and the error of bone density detection was 0.16 mm.
    IEEJ Transactions on Industry Applications 01/2013; 133(3):328-334. DOI:10.1541/ieejias.133.328
  • K. Yu · S. Iwata · K. Ohnishi · H. Kawana · S. Usuda ·
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    ABSTRACT: An estimation of bone density is important for dental implant. CT value has been used in clinical and diagnostic as a quantitative evaluation method of bone density. In this paper, a method for estimating the CT value is proposed by modeling the relation between the cutting force and the CT value. The cutting force is calculated by the thrust force of the linear motor and the torque of the rotary motor. The estimated CT value can be obtained in real time by comparing between the force from reaction force observer and the formula of CT value with the pre-estimated parameters. The validity of the proposal was confirmed through experiments using wood mentioned in Misch's bone density classification. The experimental results indicated that the error of CT value estimation was ±91 HU and the estimation accuracy was 84 %.
    Industrial Electronics Society, IECON 2013 - 39th Annual Conference of the IEEE; 01/2013
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    Yusuke Kasahara · Hiromasa Kawana · Shin Usuda · Kouhei Ohnishi ·
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    ABSTRACT: Drilling is used in the medical field, especially in oral surgery and orthopaedics. In recent years, oral surgery involving dental implants has become more common. However, the risky drilling process causes serious accidents. To prevent these accidents, supporting systems such as robotic drilling systems are required. A telerobotic-assisted drilling system is proposed. An acceleration-based four-channel bilateral control system is implemented in linear actuators in a master-slave system for drill feeding. A reaction force observer is used instead of a force sensor for measuring cutting force. Cutting force transmits from a cutting material to a surgeon, who may feel a static cutting resistance force and vigorous cutting vibrations, via the master-slave system. Moreover, position scaling and force scaling are achieved. Scaling functions are used to achieve precise drilling and hazard detection via force sensation. Cutting accuracy and reproducibility of the cutting force were evaluated by angular velocity/position error and frequency analysis of the cutting force, respectively, and errors were > 2.0 rpm and > 0.2 mm, respectively. Spectrum peaks of the cutting vibration were at the theoretical vibration frequencies of 30, 60 and 90 Hz. The proposed telerobotic-assisted drilling system achieved precise manipulation of the drill feed and vivid feedback from the cutting force.
    International Journal of Medical Robotics and Computer Assisted Surgery 06/2012; 8(2):221-9. DOI:10.1002/rcs.457 · 1.53 Impact Factor
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    ABSTRACT: Bone defects caused by traumatic bone loss or tumor dissection are now treated with auto- or allo-bone graft, and also occasionally by artificial bone transplantation, particularly in the case of large bone defects. However, artificial bones often exhibit poor affinity to host bones followed by bony union failure. Thus therapies combining artificial bones with growth factors have been sought. Here we report that platelet derived growth factor bb (PDGFBB) promotes a significant increase in migration of PDGF receptor α (PDGFRα)-positive mesenchymal stem cells/pre-osteoblastic cells into artificial bone in vivo. Growth factors such as transforming growth factor beta (TGFβ) and hepatocyte growth factor (HGF) reportedly inhibit osteoblast differentiation; however, PDGFBB did not exhibit such inhibitory effects and in fact stimulated osteoblast differentiation in vitro, suggesting that combining artificial bones with PDGFBB treatment could promote host cell migration into artificial bones without inhibiting osteoblastogenesis.
    Biochemical and Biophysical Research Communications 04/2012; 421(4):785-9. DOI:10.1016/j.bbrc.2012.04.084 · 2.30 Impact Factor
  • H. Kawana · S. Usuda · Y. Kasahara · K. Ohnishi · T. Nakagawa ·

    Journal of Oral and Maxillofacial Surgery 09/2011; 69(9). DOI:10.1016/j.joms.2011.06.164 · 1.43 Impact Factor