Kenya Okumura

Mie University, Tu, Mie, Japan

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Publications (25)38.48 Total impact

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    ABSTRACT: We encountered a patient with herpes zoster that initially developed in the mandibular gingival mucosa and induced concomitant spontaneous tooth exfoliation and meningoencephalitis. The patient was a 72-year-old man was diagnosed with herpes zoster of the region innervated by the third branch of the left trigeminal nerve, and treatment with acyclovir at 750 mg/day, div, was initiated. On the following day, the consciousness became disturbed, and the patient was diagnosed with herpes zoster-associated meningoencephalitis at the neurology department of our hospital. The dose of acyclovir was doubled, and steroid pulse therapy was administered concomitantly. The disturbance of consciousness improved and the enanthema disappeared on the 14th hospital day. But spontaneous exfoliation of the left lower second premolar occurred on the 47th hospital day. Based on the elevated serum VZV IgG level measured during the first examination, elevation of the cerebrospinal fluid VZV IgG level during the course, VZV DNA positivity on PCR, and the clinical course, the disease was considered to be herpes zoster that developed initially in the oral mucosa and became complicated by meningoencephalitis and spontaneous tooth exfoliation.
    No preview · Article · Sep 2013
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    ABSTRACT: Calcifying epithelioma, a benign tumor derived from the hair apparatus and consisted of hair matrix cells, is relatively prevalent in females. We report a case of right preauricular calcifying epithelioma that was incidentally detected at the examination of multiple facial fractures and became an old lesion without symptoms for 40 years. The patient who was a 42-year-old male visited our department for the first time in October 2011 with a chief complaint of multiple facial fractures. Radiographic imaging demonstrated fracture lines at the anterior and posterior walls of the left maxillary sinus and zygomatic arch and revealed a mass at a right preauricular area. The extraction was performed under general anaesthesia. No recurrence has been observed 15 months after surgery. We also reviewed the literature of calcifying epithelioma.
    Full-text · Article · Aug 2013
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    ABSTRACT: We present a case of carcinoma ex pleomorphic adenoma on the right buccal mucosa in a 52-year-old Japanese woman. Based on the histopathology, the excised tumor was the non-invasive type, but the majority of the tumor consisted of poorly-differentiated adenocarcinoma cells. We performed proton radiation after the surgery. The patient was well, without evidence of disease, 48 months after surgery. Carcinoma ex pleomorphic adenoma in the buccal mucosa has been reported in only four cases during the past twenty years. Therefore, our case was comparatively rare.
    No preview · Article · Jun 2013 · Journal of Maxillofacial and Oral Surgery
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    ABSTRACT: Odontogenic fibroma is a relatively rare and benign odontogenic tumor of mesodermal dental sac or periodontal ligament origin. We report a case of central odontogenic fibroma (COF) mimicking a dentigerous cyst associated with an impacted left mandibular third molar, together with immunohistological studies and a literature review. Including present case, a total of 24 cases of COF have been investigated immunohistologically to determine the origin of epithelial components or fibroblasts found in the parenchyma of the tumors. In the present case, the epithelial components were strongly positive for cytokeratin (CK AE1/AE3), and the fibroblasts were positive for vimentin. The site around the hard tissue was strongly stained by vimentin. Surgical findings indicated that the tumor extended to the periodontal ligament, suggesting that the tumor possibly originated in the periodontal ligament. A review of the literature revealed that COF occurs in the fourth to fifth decade, exhibits no sex difference, and has a good prognosis after surgery. Radiographic images of COF occasionally mimic dentigerous cysts, but there are no particular radiographic features distinguishing COF. Diagnosis is usually based on histological findings. Immunohistological studies may also be useful in the diagnosis of COF.
    No preview · Article · Apr 2013
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    ABSTRACT: The prognosis for malignant melanoma is poor; therefore, new diagnostic methods and treatment strategies are urgently needed. Phosphodiesterase 2 (PDE2) is one of 21 phosphodiesterases, which are divided into 11 families (PDE1-PDE11). PDE2 hydrolyzes cyclic AMP (cAMP) and cyclic GMP (cGMP), and its binding to cGMP enhances the hydrolysis of cAMP. We previously reported the expression of PDE1, PDE3 and PDE5 in human malignant melanoma cells. However, the expression of PDE2 in these cells has not been investigated. Herein, we examined the expression of PDE2A and its role in human oral malignant melanoma PMP cells. Sequencing of RT-PCR products revealed that PDE2A2 was the only variant expressed in PMP cells. Four point mutations were detected; one missense mutation at nucleotide position 734 (from C to T) resulted in the substitution of threonine with isoleucine at amino acid position 214. The other three were silent mutations. An in vitro migration assay and a terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling assay revealed that suppressing PDE2 activity with its specific inhibitor, erythro-9-(2-hydroxy-3-nonyl)-adenine (EHNA), had no impact on cell motility or apoptosis. Furthermore, the cytotoxicity of EHNA, assessed using a trypan blue exclusion assay, was negligible. On the other hand, assessment of cell proliferation by BrdU incorporation and cell cycle analysis by flow cytometry revealed that EHNA treatment inhibited DNA synthesis and increased the percentage of G2/M-arrested cells. Furthermore, cyclin A mRNA expression was downregulated, while cyclin E mRNA expression was upregulated in EHNA-treated cells. Our results demonstrated that the PDE2A2 variant carrying point mutations is expressed in PMP cells and may affect cell cycle progression by modulating cyclin A expression. Thus, PDE2A2 is a possible new molecular target for the treatment of malignant melanoma.
    Full-text · Article · Jan 2013 · Oncology Reports
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    ABSTRACT: Mucous cysts occur often and are often treated in a clinical setting. However, gingival mucous cysts are extremely rare. The case of a patient who developed a gingival mucous cyst in an edentulous mandible during distraction of the mandible is described here. The patient was a 78-year-old man with a history of squamous cell carcinoma of the left lower lip and the right mandibular gingiva. The patient had been fitted with a distraction device prior to undergoing dental implant therapy to replace missing teeth. During bone lengthening, a bean-size tumor was confirmed in the gingiva corresponding to the left mandibular premolar region. The tumor was clinically diagnosed as a benign mandibular gingival tumor and was excised surgically. It was then histopathologically diagnosed as an extravasated mucous cyst. The cyst had arisen in the gingiva that developed during distraction of the mandible. Distraction devices are used in patients with trauma-induced alveolar bone defects, among other problems, but caution must be exercised when using a distraction device in a large tissue defect without attached gingiva.
    No preview · Article · Aug 2012
  • T. Takeoka · K. Okumura · H. Kato · Y. Matsumura · M. Inui · T. Tagawa

    No preview · Article · Oct 2011 · International Journal of Oral and Maxillofacial Surgery
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    K Noguchi · M Nakase · M Inui · S Nakamura · K Okumura · T Tagawa
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    ABSTRACT: Graft-versus-host disease (GVHD) can occur at various sites, including the oral mucosa, where it is associated with a high risk of head and neck cancer. We report the case of a 46-year-old woman with tongue cancer that developed following Hodgkin's lymphoma and chronic GVHD, and we discuss the possible causes of cancer development.
    Full-text · Article · Jun 2010 · Australian Dental Journal

  • No preview · Article · Mar 2010 · Special Care in Dentistry
  • K. Okumura · M. Nakase · M. Inui · Y. Matsumura · J. Nomura · T. Tagawa

    No preview · Article · Jul 2009 · Oral Oncology Supplement
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    ABSTRACT: Bax is a pro-apoptotic molecule that functions as a tumor suppressor and Bax gene therapy has been examined for various cancers. Gene transfer by mRNA lipofection is more efficient than plasmid DNA lipofection and, in the present study, we examined the anti-tumor effects in human malignant melanoma cells (HMGs) using Bax mRNA lipofection. Bax protein expression, cell growth inhibition, caspase-3 activity and apoptosis were examined in vitro. Liposome-Bax mRNA was applied locally once every 5 days for a total of five times to peripheral HMG tumors transplanted in nude mice. Tumor growth inhibition was evaluated by measuring the tumor volume and apoptosis was detected using a terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling (TUNEL) assay. Enhanced expression of Bax protein was observed following Bax mRNA transfer and cell survival was 59.8%. Caspase-3 activity and TUNEL-positive cells increased significantly following Bax mRNA lipofection compared to Bax plasmid transfer. In mice, tumor growth increased only slightly during liposome-Bax mRNA administration and the tumor volume on day 30 (10 days after completion of administration) was 36.7% of that in the saline control group. By contrast, Bax plasmid transfection resulted in little change in tumor growth compared to controls. Bax mRNA therapy using liposomes has stronger anti-tumor effects than Bax gene therapy using a plasmid, and the results suggest that Bax mRNA lipofection may be a viable treatment for malignant melanoma.
    No preview · Article · Aug 2008 · The Journal of Gene Medicine
  • K. Okumura · M. Nakase · S. Nakamura · M. Inui · T. Tagawa

    No preview · Article · Nov 2007 · International Journal of Oral and Maxillofacial Surgery
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    ABSTRACT: The purpose of this study was to evaluate the anti-tumor effect of human osteosarcoma (HOSM-1) tumor xenografts in nude mice via transfer of the Bax gene using cationic liposomes. The HOSM-1 tumors transplanted into nude mice grew to 5-6 mm in diameter. Following growth of the tumor to this size, liposomes with the Bax plasmid were applied locally to the peripheral tumor (day 0) and were applied 3 times per week for 2 weeks (6 times in total). The tumor growth inhibitory effect was evaluated by measuring the tumor volume up to day 40. The expression of Bax was observed by immunohistochemical analysis and apoptosis was detected using the TUNEL assay. Tumor growth increased only slightly during the administration period, and tumor volume on day 50 was 43% of that in the saline control group. In the tumor margin 48 h after the completion of administration, Bax immunoreactivity was detected and apoptotic cells were clearly increased. Since these results suggested that Bax gene therapy using cationic liposome induced apoptosis in HOSM-1 tumor in vivo, we anticipate that this therapy will be useful for the treatment of osteosarcoma.
    No preview · Article · May 2007 · Oncology Reports
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    ABSTRACT: Submandibular Gland Mucocele:The mucocele occuring in the submandibular region is rare, most cases originate in the sublingual gland. Here, we report a rare case of mucocele originating in the submandibular gland. In this report, we present such a case in a 7-year-old boy, who was treated by an extirpation of cyst with submandibular and sublingual gland
    No preview · Article · Feb 2007 · The Journal of clinical pediatric dentistry
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    ABSTRACT: G3139 is an 18-mer phosphorothioate oligodeoxynucleotide (ODN) which has been targeted on the initiation codon region of the bcl-2 gene. Currently, clinical trials on G3139 for diverse tumors are underway in phase II and phase III. However, basic investigations of bcl-2 antisense ODN (G3139) and reverse ODN (G3622) have not been fully examined. In this report, we investigate cell death caused by G3139 and G3622 and the impact of antisense ODN in melanoma cell lines. We confirmed that G3139 reduced the level of bcl-2 protein and both G3139 and G3622 inhibited cell proliferation and induced apoptosis. G3139 was noted to produce a more intense effect than G3622. Although the general caspase inhibitor, Z-VAD-fmk, prevented apoptosis incompletely, the inhibition ratio of both ODNs was approximately equivalent. Our results suggested that inhibition of cell proliferation by ODNs is produced by apoptosis, but that the apoptotic pathway is not fully induced by the caspase-dependent pathway. Upon examination of the intracellular apoptotic protein dynamics, AIF localized within the mitochondria was translocated to the cytosol within 24 h, and subsequently to the nuclei after 48 h of treatment with G3139. Our results imply the following: the transfection of ODNs can induce apoptosis, the anti-tumor effect of G3139 is better than G3622, and the difference in the anti-tumor effect is specifically based upon the reduction of expression of the target DNA in malignant tumors. We consider that antisense ODNs may be an important tool for anti-tumor chemotherapy and the targeting of specific DNA is important in enhancing the anti-proliferative effect against tumors.
    No preview · Article · Jul 2006 · Oncology Reports
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    ABSTRACT: The Fas receptor is a potentially valuable therapeutic target in cancer treatment. However, the clinical application of antibodies directed to this target is hindered by their serious side effects in vivo, including liver toxicity. One murine monoclonal antibody, mHFE7A, binds both to human Fas and murine Fas, without inducing any obvious side effects. However, the potential therapeutic effects of mHFE7A are unclear in human cancer cells or tumors. Here, we determined whether mHFE7A could induce apoptosis in vitro, and assessed its effects on major apoptotic pathways in a human melanoma cell line, MMN9. We also investigated its anti-cancer effects on transplanted melanoma MMN9 tumors in BALB/c nude mice. Treatment of mHFE7A cross-linking with Ig induced cell death similar to CH-11 treatment. Apoptosis induced by mHFE7A was defined by Hoechst 33342 DNA staining and DNA fragmentation assay. Furthermore, mHFE7A-mediated apoptosis was dependent on activation of a caspase signaling cascade involving caspases-8 and -3. Administration of mHFE7A also delayed the growth of melanoma xenografts. Thus, we provide the first evidence that the murine anti-Fas monoclonal antibody, mHFE7A, induces apoptosis of human malignant melanoma cells in vitro and is anti-tumorigenic in vivo.
    No preview · Article · Mar 2006 · Oncology Reports
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    ABSTRACT: The transfection efficiency of cationic liposomes varies according to cell type, but the specific cellular characteristics that affect transfection efficiency have not yet been defined. We investigated whether the transfection efficiency of cationic liposomes correlates with cell proliferation activity or cell membrane potential in oral malignant melanoma (HMG) and oral osteosarcoma cell lines (HOSM-1 and HOSM-2). The cell membrane potential was assessed by uptake of a cationic probe. Three oral tumor cell lines were exposed to a cationic liposome complexed with a beta-galactosidase expression plasmid, and beta-galactosidase expression was compared. Cell proliferation was about 2-fold higher in HOSM-1 cells than in HMG cells. The cell membrane potential in HMG and HOSM-1 cells was comparable, while the membrane potential in HOSM-2 cells was 1.6-fold higher. beta-galactosidase expression was measured by X-Gal staining in 7.0% of HMG, 17.0% of HOSM-1 and 11.5% of HOSM-2 cells. The present study demonstrates that gene therapy with cationic liposomes may be a promising new strategy for treatment of oral malignant melanoma and osteosarcoma. In addition, the transfection efficiency of cationic liposomes appears to be influenced by cell proliferation activity, but not cell membrane potential.
    No preview · Article · Jan 2006 · Oncology Reports
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    ABSTRACT: The Fas/FasL signalling system plays an important role in chemotherapy-induced apoptosis in several different cell types. After interferon-gamma (IFN-gamma) treatment, we have previously reported a significant increase in Fas expression in oral malignant melanoma cell lines (MMN9, PMP, MAA, HMG) in vitro, and combination therapy using IFN-gamma and anti-Fas antibody (CH-11) has shown a synergistic anti-proliferative effect in MMN9 cells. There have been several in-vitro studies using CH-11, but there are few reports of its anti-tumour effect in vivo. In this study, we investigated experimental therapy using anti-Fas antibody against MMN9 in vivo in a mouse model, and histologically examined tumour tissue removed from BALB/c nude mice. Animals that received both IFN-gamma and CH-11 showed a 53.8% increase in anti-tumour effect (P=0.0018) 20 days after the first administration. In the histological study, the combined administration group tested positive in terminal deoxynucleotidyl transferase-mediated nick end labelling staining, and showed significantly increased levels of Fas expression on immunostaining compared with the vehicle group. These results show the efficacy of anticancer therapy using IFN-gamma and anti-Fas antibody via the modulation of Fas-mediated apoptosis. Moreover, inhibition of IFN-gamma/CH-11-induced apoptosis with a general caspase inhibitor (benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone) reduced cell death significantly in vitro. Bcl-2 cleavage did not occur under these conditions, suggesting a relationship between caspase activation and Bc1-2 cleavage in MMN9 cells.
    No preview · Article · Nov 2005 · Melanoma Research
  • T Tamura · M Inui · M Nakase · S Nakamura · K Okumura · T Tagawa
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    ABSTRACT: The purpose was to evaluate carotid calcifications on panoramic radiographs, and relate to risk factors for vascular diseases. Between 1997 and 2001, 2568 radiographs were retrospectively collected from new patients at Mie University Hospital whose ages ranged from 50 to 70 years. The mean age of the subjects was 62.2 years (men 61.9 years, women 62.3 years). Medical and social data were collected from case notes, and body weight, height, and age of menopause confirmed by telephone interviews. About 106 carotid calcifications were found on the panoramic radiographs of 26 males and 80 females. The ratio of males to females was 1:3.07. The subjects with carotid calcifications had medical histories that included hypertension (27.6%), obesity (21.1%), hyperlipidemia (14.5%), and cardiovascular diseases (13.2%), all with recognized risk factors for atheromas. Of 76 patients who responded to follow up interviews, two (2.63%) died from cardiovascular stroke during an average follow up of 2.43 years. The results show carotid calcifications detected on panoramic radiographs can be used to help predict vascular strokes in patients. In cases where calcified carotid artery atheromas are detected, the dentist or oral and maxillofacial surgeon should refer the patient to a specialized physician.
    No preview · Article · Oct 2005 · Oral Diseases
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    ABSTRACT: The purpose of this study was to evaluate the anti-tumor effects of osteosarcoma (HOSM-1) cells via transfer of the Bax gene using a cationic liposome. We evaluated the levels of Bax, Bcl-xL, Bcl-2 and cytochrome c expression by Western blot analysis, and caspase-9 and -3 activities were determined in a colorimetric assay. Apoptosis was detected using a TUNEL assay, and cell growth inhibition was determined in an MTT assay. Following Bax gene transfer, release of cytochrome c to the cytosol was detected, the activities of caspase-9 and -3 increased, and TUNEL-positive cells (37.5%) were detected. Cell survival rate was 50.8% under these conditions. Induction of apoptosis was inhibited by a caspase inhibitor (zVAD-fmk), but only a slight increase in cell survival rate occurred. Hence, since not only apoptosis but also caspase-independent cell death is induced in HOSM-1 cells, we anticipate that Bax gene therapy with cationic liposomes will be useful for osteosarcoma.
    No preview · Article · Sep 2005 · International Journal of Oncology

Publication Stats

175 Citations
38.48 Total Impact Points


  • 2004-2013
    • Mie University
      • Department of Oral and Maxillofacial Surgery
      Tu, Mie, Japan
  • 2010
    • Center For Oral & Maxillofacial Surgery
      Georgia, United States