Geniku Kohama

Sapporo Medical University, Sapporo-shi, Hokkaido, Japan

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Publications (7)16.87 Total impact

  • Article: Speech evaluation and dental arch shape following pushback palatoplasty in cleft palate patients: Supraperiosteal flap technique versus mucoperiosteal flap technique.
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    ABSTRACT: The aim of this study was to evaluate and compare the maxillary dental arch shape and speech of cleft palate patients following pushback palatoplasty using either the supraperiosteal flap technique or the mucoperiosteal flap technique. Sixty-two patients (29, cleft palate only; 33, unilateral cleft lip, alveolus and palate) operated on by the supraperiosteal technique and 47 patients (23, cleft palate only; 24 unilateral cleft lip, alveolus and palate) by the mucoperiosteal technique were reviewed in this study. Study design: Dental arch shape and speech proficiency at preschool and school age were evaluated in all patients. Dental arch shapes were classified as U type (good dental arch shape) and V type (narrow dental arch shape). In cleft palate only patients, U type was observed in 90% of the supraperiosteal group and 83% of the mucoperiosteal group. In unilateral cleft lip, alveolus and palate patients, U type was observed in 85% of the supraperiosteal group, while only in 33% of the mucoperiosteal group. In cleft palate only patients, normal speech at school age was observed 100% of the supraperiosteal group and 83% of the mucoperiosteal group. In unilateral cleft lip, alveolus and palate patients, normal speech at school age was observed in 97% of the supraperiosteal group and 75% of the mucoperiosteal group. Misarticulation was frequently found in patients with the V type of dental arch shape. It is suggested that pushback palatoplasty using the supraperiosteal technique is more advantageous for speech development compared with the mucoperiosteal technique.
    Journal of Cranio-Maxillofacial Surgery 05/2006; 34(3):135-43. · 1.64 Impact Factor
  • Article: Enhanced Bax in oral SCC in relation to antitumor effects of chemotherapy.
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    ABSTRACT: Antitumor effects of chemotherapeutic agents are commonly associated with the induction of apoptosis. Bax belongs to the Bcl-2 family and induces apoptosis. The present study was conducted to investigate the relationship between enhanced Bax expression in oral squamous cell carcinoma (SCC; cell lines and clinical cases) and the antitumor effects of chemotherapy. In three oral SCC cell lines, Bax expression before and after treatment with chemotherapeutic agents [docetaxel (TXT), cisplatin and 5-fluorouracil] was examined by reverse transcriptase-polymerase chain reaction and immunoblotting. The effects of treatment were assessed by counting the number of viable cells and determining sub-G1 cells. Tissue samples (both biopsy specimens before chemotherapy and surgically excised specimens after chemotherapy) from nine patients with oral SCC who underwent neoadjuvant chemotherapy were immunostained for Bax. The relationship between enhancement of Bax expression and chemotherapeutic effects was established. Two of three cell lines did not express Bax mRNA or protein before treatment. After treatment, Bax expression was enhanced only by TXT in one cell line, but by all chemotherapeutic agents in the other two cell lines. In three of nine patients, Bax expression was not found before chemotherapy. Two of these three patients showed enhanced Bax expression after chemotherapy including TXT, but one still failed to express Bax. Both in cell lines and clinical cases, enhancement of Bax after chemotherapy was associated with antitumor effects. Certain chemotherapeutic agents enhance Bax expression in oral SCC, and it is suggested that this contributes to the antitumor effects of chemotherapy.
    Journal of Oral Pathology and Medicine 03/2005; 34(2):93-9. · 1.63 Impact Factor
  • Article: Sternocleidomastoid myocutaneous flap for intraoral reconstruction after resection of oral squamous cell carcinoma.
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    ABSTRACT: The sternocleidomastoid (SCM) myocutaneous flap remains an important tool in head and neck reconstruction. This article retrospectively reviews 40 consecutive SCM myocutaneous flaps used for the reconstruction after resection of oral squamous cell carcinoma with respect to reliability and complications. From 1987 to 1997, 40 patients underwent SCM myocutaneous flap reconstruction of the oral cavity. The age and gender of the patients, site of primary tumor TNM stage, type of associated operation, and clinical course were analyzed. In 8 cases, partial epithelial loss over the skin paddle occurred with survival of the muscle and at least some of the dermis. Unilateral supraomohyoid neck dissection (SND) was performed in 11 cases, and unilateral functional neck dissection, which preserves SCM and/or internal jugular vein and/or accessory nerve, in 16 cases. Pathologically positive nodes were recognized in 14 of these 27 neck dissection cases; in 11 of these 14 cases, the neck lesion was controlled. The SCM myocutaneous flap appears to be simple to use and useful for reconstruction of the defect after resection of oral carcinoma, and the indications for this flap will be extended in accordance with the recent increases in the number of supraomohyoid and functional neck dissection cases.
    Journal of Oral and Maxillofacial Surgery 11/2003; 61(10):1179-83. · 1.64 Impact Factor
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    Article: Enhanced antitumor effect of RGD fiber-modified adenovirus for gene therapy of oral cancer.
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    ABSTRACT: Current clinical success rates of adenoviral vector (Adv)-based gene therapy of squamous cell carcinoma (SCC) of the head and neck remain unsatisfactory. A major problem with this approach is thought to be related to low Adv transduction efficiency due to weak expression of the adenovirus receptor, coxsackie-adenovirus receptor (CAR), in SCC. To improve the limited infectivity of Adv in oral SCC, we constructed mutated Adv incorporating the integrin-binding motif, RGD, in the HI loop of the fiber knob. The mutated Adv infected target cells through integrins commonly expressed in oral SCC. LacZ marker gene expression after infection with this mutated Adv (Adv-F/RGD) in oral SCC cell lines that showed reduced expression of CAR was approximately 5-10 times higher than that obtained with the parental Adv containing wild-type fiber knob (Adv-F/wt). In an in vitro study, transduction of oral cancer cell lines with Adv-F/RGD expressing human IL-2 (AxCAhIL2-F/RGD) resulted in greater production of cytokine than AxCAhIL2-F/wt infection. In an in vivo therapeutic xenograft model of oral SCC in nude mice, AxCAhIL2-F/RGD demonstrated antitumor effects superior to those of AxCAhIL2-F/wt. These data suggest that exploitation of genetically altered adenovirus vectors with integrin-binding motifs may offer significant improvements in oral SCC gene therapy.
    Cancer Gene Therapy 02/2003; 10(1):75-85. · 2.80 Impact Factor
  • Article: Aberrant methylation of multiple genes and clinicopathological features in oral squamous cell carcinoma.
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    ABSTRACT: The purpose of this study was to examine the methylation profile of various oral squamous cell carcinomas and to correlate the methylation of particular chromosomal loci with the clinicopathological features of the tumors. A semiquantitative analysis of the methylation status of 12 loci in 96 primary tumors and 13 cell lines was carried out. Methylation frequency was calculated as the percentage of methylated alleles detected by bisulfate-PCR. Of the 12 loci examined, 9 (p16INK4A, p15INK4B, p14ARF, DCC, DAP kinase, MINT1, MINT2, MINT27, and MINT31) exhibited aberrant methylation at various frequencies, whereas 3 (hMLH1, HRK, and CACNA1G) showed no methylation. Dense methylation of the 5' CpG island of DAP kinase and MINT1 was well correlated with loss of gene expression. In addition, methylation of DCC was correlated with bone invasion by gingival tumors (P = 0.036), with aggressive invasiveness of tumors of the tongue (P = 0.046), and with reduced survival (P = 0.050). Methylation of MINT1 and MINT31 also correlated with poor prognoses (P = 0.058 and 0.041), whereas methylation of p14ARF correlated with a good prognosis (P = 0.021). Cox regression analysis showed methylation of MINT31 to be an independent predictor of outcome (hazard ratio, 3.79; 95% confidence interval, 1.58-9.10) and to be associated with the T4 disease group (hazard ratio, 5.71; 95% confidence interval, 1.25-26.07). Analysis of DNA methylation is a useful approach to evaluation of the biological characteristics of oral cancers and may be a useful diagnostic indicator of patient prognosis.
    Clinical Cancer Research 11/2002; 8(10):3164-71. · 7.74 Impact Factor
  • Article: Control of cell proliferation kinetics of tumor in neoadjuvant chemotherapy for advanced oral squamous cell carcinoma and its prognostic implications.
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    ABSTRACT: Few attempts have so far been made at studies of the cell proliferation kinetics of the tumor in neoadjuvant chemotherapy for head and neck cancer. We examined the effects of neoadjuvant chemotherapy for advanced oral squamous cell carcinoma in terms of the cell proliferation kinetics of the tumor, and attempted to correlate them with patients' survival. Fifty-two patients with advanced oral squamous cell carcinoma who received neoadjuvant chemotherapy followed by surgery participated in this study. Cellular DNA content and mitotic index (MI) in tissue samples were measured before and after chemotherapy, using a cell image analyzer. A decrease in both mean DNA content (mean DNA) and MI (left-shift type of change in cell growth kinetics), indicating an accumulation of cancer cells in the G0-G1 phase, was found in 25 patients. An increase in mean DNA with decreased MI (right-shift type), which was found in 13 patients, appeared to be correlated with an accumulation of cancer cells in the S-G2 phase. Neither of these two types of change, which were considered to be a favorable effect, were found in 14 patients (ineffective type). Excellent survival rates were obtained in patients who showed favorable changes in cell growth kinetics (79% for patients with left-shift type and 92% for patients with right-shift type), whereas the survival rate for patients with the ineffective type was extremely poor (14%). The type of change in cell proliferation kinetics was a powerful independent prognostic indicator. Analysis of cell growth kinetics appears to be useful not only as a diagnostic tool to predict patient outcome but also as a means to infer the chemotherapeutic effects in oral squamous cell carcinoma.
    International Journal of Clinical Oncology 07/2002; 7(3):138-44. · 1.41 Impact Factor
  • Article: Clinical features and management of oral and maxillofacial tumors in children
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    ABSTRACT: Objective. To clarify the characteristics of oral and maxillofacial tumors in children, we carried out a clinical study of such tumors and reviewed the relevant procedures for treatment. Study design. Medical records of 105 patients less than 15 years of age who were treated for oral and maxillofacial tumors during the 20 years between 1976 and 1997 were retrieved and analyzed. Results. Of the 105 cases, 102 (97.1%) involved tumors that were benign; only 3 patients (2.9%) had tumors that were malignant. With regard to benign soft tissue tumor, the most common type was hemangioma (25/69; 36.2%), the second most common type was papilloma (19/69; 27.5%), and the most common site was the tongue. With regard to bone tumor, the most common type was odontoma (14/33; 42.4%), the second most common type was ameloblastoma (11/33; 33.3%), and the most common site was the mandible. Most of the odontogenic tumors (25/28; 89.3%) developed in patients more than 6 years of age; these tumors may develop after dental crown formation. In each case of benign soft tissue tumor, resection was performed; 4 of these tumors (2 hemangiomas, 1 lymphangioma, and 1 papilloma) recurred, but after re-resection recurrence has not been found for more than 4 years. In the cases of benign jawbone tumor, resection and enucleation were the procedures principally performed; 3 ameloblastomas recurred after enucleation, but after relatively wide resection for these recurrent tumors there has been no recurrence for more than 17 years. With regard to the ameloblastomas, enucleation with preservation of the periosteum was effective and bone regeneration occurred rapidly. Conclusions. Most oral and maxillofacial tumors in children are benign. In any case of such benign tumor, including ameloblastoma, minimal surgical treatment should be the procedure of first choice. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1999;88: 11-15)
    Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontology.