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Primary extranodal lymphoma of the maxilla: a case report with imaging features and dynamic data analysis of magnetic resonance imaging. 査読国際誌

Hidenobu Matsuzaki, Naoki Katase, Marina Hara, Jun-Ichi Asaumi, Yoshinobu Yanagi, Teruhisa Unetsubo, Miki Hisatomi, Hironobu Konouchi, Toshihiko Takenobu, Hitoshi Nagatsuka

Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics 112 ( 3 ) e59-69 - E69 2011年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：MOSBY-ELSEVIER

Malignant lymphoma is the second-most common malignancy in the head and neck region. Waldeyer's ring is the most common site of extranodal Hodgkin's lymphoma (NHL) in that region, and a small percentage of primary extranodal NHL occurs in the oral cavity. The most common sites of extranodal NHL in the oral region are the palate and maxilla, and nearly half of extranodal NHL cases arise from bone. It is difficult to diagnose extranodal NHL because of the variety of its radiological features. We report a case of primary extranodal NHL of the maxilla in a 68-year-old female patient with atypical imaging findings, along with the results of analysis of dynamic magnetic resonance imaging (MRI).

DOI： 10.1016/j.tripleo.2011.02.052

Ameloblastic carcinoma: a case report with radiological features of computed tomography and magnetic resonance imaging and positron emission tomography. 査読国際誌

Hidenobu Matsuzaki, Naoki Katase, Marina Hara, Jun-Ichi Asaumi, Yoshinobu Yanagi, Teruhisa Unetsubo, Miki Hisatomi, Hironobu Konouchi, Hitoshi Nagatsuka

Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics 112 ( 1 ) e40-7 - E47 2011年7月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：MOSBY-ELSEVIER

Ameloblastic carcinoma is a rare malignant odontogenic carcinoma that has metastatic potential, and because of its rare incidence, there are few reports focusing on its radiologic imaging. If it shows aggressive appearances, it can be diagnosed as malignant tumor. But in case of negative appearance, it is difficult to distinguish ameloblastic carcinoma from ameloblastoma. We report a case of ameloblastic carcinoma of the maxilla in a 76-year-old female patient with radiologic images and pathologic features.

DOI： 10.1016/j.tripleo.2011.01.023

Corticomotor plasticity induced by tongue-task training in humans: a longitudinal fMRI study. 国際誌

Taro Arima, Yoshinobu Yanagi, David M Niddam, Noboru Ohata, Lars Arendt-Nielsen, Shogo Minagi, Barry J Sessle, Peter Svensson

Experimental brain research 212 ( 2 ) 199 - 212 2011年7月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：SPRINGER

Corticomotor pathways may undergo neuroplastic changes in response to acquisition of new motor skills. Little is known about the motor control strategies for learning new tongue tasks. The aim of this study was to investigate the longitudinal effect of novel tongue-task training on corticomotor neuroplasticity. Thirteen healthy, right-handed men, aged 24-35 years (mean age ± SD: 27.3 ± 0.3 years), performed a training task consisting of standardized tongue protrusion onto a force transducer. The tongue task consisted of a relax-protrude-hold-relax cycle with 1.0 N as the target at the hold phase lasting for 1.5 s. Subjects repeated this task for 1 h. Functional magnetic resonance imaging was carried out before the tongue-task training (baseline), 1-h after the training, and one-day and one-week follow-up. During scanning, the subjects performed tongue protrusion in blocks interspersed with rest. A region-of-interest (ROI) approach and an explorative search were implemented for the analysis of corticomotor activity across conditions. All subjects completed the tongue-task training (mean success rate 43.0 ± 13.2%). In the baseline condition, tongue protrusion resulted in bilateral activity in regions most typically associated with a motor task including medial frontal gyrus (supplementary motor area [SMA]), precentral gyrus (tongue motor cortex), putamen, thalamus, and cerebellum. The ROI analysis revealed increased activity in the precentral gyrus already 1 h post-training. One day after the training, increased activity was observed in the precentral gyrus, SMA, putamen, and cerebellum. No increase was found 1 week after training. Correlation analyses between changes in success rates and changes in the numbers of voxels showed robust associations for left Area 4a in primary motor cortex 1 h, 1 day, and 1 week after the tongue-task training and for the left Area 4p in primary motor cortex and the left lateral premotor cortex 1 day after the training. In the unrestricted analysis, increased activity was found in the parahippocampal gyrus 1 h after the tongue-task training and remained for a week. Decreased activity was found in right post-central and middle frontal gyri 1 h and 1 week post-training. The results verified the involvement of specific corticomotor areas in response to tongue protrusion. Short-term tongue-task training was associated with longer-lasting (up to 1 week) changes in motor-related brain activity. The results suggested that primary motor areas are involved in the early and late stages, while other motor areas mainly are engaged in the later stage of corticomotor neuroplasticity of the tongue.

DOI： 10.1007/s00221-011-2719-7

Dynamic contrast-enhanced magnetic resonance imaging in head and neck tumors

Jun ichi Asaumi, Miki Hisatomi, Hironobu Konouchi, Teruhisa Unetsubo, Yoshinobu Yanagi

Oral Cancer: Causes, Diagnosis and Treatment 1 - 50 2011年4月

掲載種別：論文集(書籍)内論文

Magnetic resonance imaging (MRI) is effective for diagnosing tumors and has some advantages over traditional techniques, especially in detecting soft tissue lesions. However, MRI examination has not yet come into use for the differential diagnosis of tumors or for determining whether a tumor is benign or malignant. It has been reported that dynamic contrast-enhanced MRI (DCE-MRI) is useful for the differential diagnosis of some tumors, and many investigators have attempted to use it to identify differences between benign and malignant tumors, as well as to assess the malignancy of tumors. Oral malignancies (carcinomas and sarcomas) may develop as primary lesions originating from any type of oral tissue. The most common oral cancers are squamous cell carcinomas (SCCs), followed by salivary grand malignant tumors such as adenoid cystic carcinomas (ACCs) and mucoepidermoid carcinomas (MECs). Malignant lymphoma is the second most common malignant tumor of the head and neck. In this chapter, we show the roles of MRI and DCE-MRI in the differential diagnosis of SCCs, salivary gland tumors, and malignant lymphoma. © 2011 by Nova Science Publishers, Inc. All rights reserved.

Diagnostic value of dynamic contrast-enhanced MRI for unilocular cystic-type ameloblastomas with homogeneously bright high signal intensity on T2-weighted or STIR MR images. 国際誌

Miki Hisatomi, Yoshinobu Yanagi, Hironobu Konouchi, Hidenobu Matsuzaki, Toshihiko Takenobu, Teruhisa Unetsubo, Jun-ichi Asaumi

Oral oncology 47 ( 2 ) 147 - 52 2011年2月

記述言語：英語掲載種別：研究論文（学術雑誌）

Typical MR images of ameloblastomas on T2-weighted image (WI) or short inversion time inversion-recovery (STIR) show multiple bright high-signal-intensity loci on a high-signal-intensity background. Unilocular cystic-type ameloblastomas show homogeneously bright high signal intensity on T2WI or STIR as a water-like signal intensity. Therefore, it is difficult to distinguish unilocular cystic-type ameloblastoma from other cystic lesions such as keratocystic odontogenic tumors, radicular cysts (residual cysts) and dentigerous cysts only on the basis of MRI signal intensity. In the present study, we evaluated whether contrast-enhanced (CE)-T1WI and dynamic CE-MRI (DCE-MRI) could provide additional information for differential diagnosis in unilocular cystic-type ameloblastoma. Images from 12 cases of suspected unilocular cystic-type ameloblastoma were evaluated in the present study. Of them, 5 had areas suspected of indicating a solid component on T1WI and T2WI (or STIR). Ten had undergone additional CE-T1WI and DCE-MRI. On 5 of 10 cases of CE-T1WI, a tiny enhancement area was detected. On 6 of 10 DCE-images, a time-course enhanced area which was suspected to be a solid component was detected. CE-T1WI was helpful in the diagnosis of ameloblastoma because the tiny enhanced areas were taken to indicate possible solid components. Moreover, the rim-enhancement area on CE-T1WI could be divided into small regions of interest, and some of these showed slightly increased enhancement on DCE-MRI, which was taken to indicate a solid component and/or intramural nodule with focal invasion of ameloblastoma tissue. DCE-MRIs of the four remaining cases, which provided no clues to the diagnosis of ameloblastoma in the manner of the above descriptions, showed thicker rim enhancement than odontogenic cysts. Thus, CE-T1WI and DCE-MRI were helpful in the differential diagnosis of unilocular cystic-type ameloblastomas with homogeneously bright high signal intensity on T2WI or STIR.

DOI： 10.1016/j.oraloncology.2010.11.009

Usefulness of MRI and dynamic contrast-enhanced MRI for differential diagnosis of simple bone cysts from true cysts in the jaw. 国際誌

Yoshinobu Yanagi, Jun-ichi Asaumi, Teruhisa Unetsubo, Masakazu Ashida, Toshihiko Takenobu, Miki Hisatomi, Hidenobu Matsuzaki, Hironobu Konouchi, Naoki Katase, Hitoshi Nagatsuka

Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics 110 ( 3 ) 364 - 9 2010年9月

記述言語：英語掲載種別：研究論文（学術雑誌）

INTRODUCTION: It can be difficult to differentiate simple bone cysts (SBCs) from true cysts in the jaw when these lesions appear unilocular. The present study reports the MR imaging of subjects with SBCs and describes the diagnostic value of the MRI findings. MATERIALS AND METHODS: Ten subjects with SBCs in the jaw were examined using MRI. T1- and T2-weighted images (T1WI, T2WI) were obtained, and contrast-enhanced images and dynamic contrast-enhanced MRI (DCE-MRI) were acquired. RESULTS: In all cases, the contrast-enhanced T1WI acquired approximately 6 minutes after the administration of Gd-DTPA showed marked enhancement of the margin and slight enhancement of the inner part of the cyst cavity. In all cases, the time-signal intensity (SI) curves show a gradual increase in the SI until approximately 15 minutes after the administration of Gd-DTPA. These findings might not be observed on the DCE-MRIs of the other true cysts with epithelial lining that show no enhancement in a cavity. CONCLUSION: MRI, especially DCE-MRI, can provide useful information for distinguishing SBCs from other cysts.

DOI： 10.1016/j.tripleo.2010.05.001

A case of malignant fibrous histiocytoma of the maxillary sinus. 国際誌

Yoshinobu Yanagi, Jun Murakami, Miki Hisatomi, Naoki Katase, Hitoshi Nagatsuka, Jun-Ichi Asaumi

Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics 109 ( 3 ) e99-e104 2010年3月

記述言語：英語掲載種別：研究論文（学術雑誌）

Malignant fibrous histiocytoma (MFH) is recognized as one of the most common soft tissue sarcomas arising in late adulthood. Most MFHs arise from the extremities and the retroperitoneum, thus the incidence of head and neck MFH is relatively low. Because of its rare incidence, there are very few reports focusing on the imaging features of MFH arising in the maxillary sinus. A case of MFH of the maxillary sinus in a 67-year-old male patient is reported including imaging and pathological features.

DOI： 10.1016/j.tripleo.2009.11.032

A case of unerupted lower primary second molar associated with compound odontoma. 国際誌

Unetsubo Teruhisa, Jun Murakami, Miki Hisatomi, Yoshinobu Yanagi, Jun-Ichi Asaumi

The open dentistry journal 3 173 - 6 2009年8月

記述言語：英語掲載種別：研究論文（学術雑誌）

Odontoma is the most common type of benign odontogenic tumor, and often causes disturbances in the eruption of its associated tooth. Odontomas usually occur in the permanent dentition, and rarely occur solely in the primary dentition. This case report documents a six-year-old-child with a compound odontoma located in the mandible, which caused the impaction of the primary second molar.

DOI： 10.2174/1874210600903010173

Dynamic contrast-enhanced magnetic resonance imaging for estimating tumor proliferation and microvessel density of oral squamous cell carcinomas. 国際誌

Teruhisa Unetsubo, Hironobu Konouchi, Yoshinobu Yanagi, Jun Murakami, Masae Fujii, Hidenobu Matsuzaki, Miki Hisatomi, Hitoshi Nagatsuka, Jun-ichi Asaumi

Oral oncology 45 ( 7 ) 621 - 6 2009年7月

記述言語：英語掲載種別：研究論文（学術雑誌）

We evaluated the relationship between histopathological prognostic factors, tumor proliferation microvessel density (MVD), and enhancement parameters in dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in oral squamous cell carcinoma (SCC). Twenty-eight T2 and T3 patients with primary oral SCC underwent DCE-MRI using three-dimensional fast imaging with a steady-state precession sequence. Tumor cell proliferation and MVD of all surgical specimens were evaluated using immunohistochemical staining with CD34 and the antibody for proliferating cell nuclear antigen (PCNA). Regression analysis was used to statistically analyze the relationship between the PCNA labeling index or MVD and each of three DCE-MRI parameters: maximum CI (CI-max), maximum CI gain (CI-gain) and the CI-gain / CI-max ratio). The PCNA labeling index and MVD showed significant correlations with the CI-gain/CI-max ratio (P=0.0012, r=0.581 and P=0.00141, r=0.574, respectively). The assessment of DCE-MRI parameters may prove to be a valuable non-invasive method for assessing tumor cell proliferation and MVD of patients with oral cancer.

DOI： 10.1016/j.oraloncology.2008.09.003

Analysis of magnetic resonance images of disk positions and deformities in 1,265 patients with temporomandibular disorder. 国際誌

Yong-Suk Choi, Jun-Ichi Asaumi, Miki Hisatomi, Teruhisa Unetsubo, Yoshinobu Yanagi, Hidenobu Matsuzaki, Hironobu Konouchi, Eui-Hwan Hwang, Sang-Rae Lee

The open dentistry journal 3 1 - 20 2009年3月

記述言語：英語掲載種別：研究論文（学術雑誌）

OBJECTIVES: To compare MRI manifestations according to gender and age and to identify correlations between clinical manifestations and MRI findings in patients with temporomandibular disorder (TMD) as based on a large series. MATERIALS AND METHODS: Fat suppressed oblique sagittal images of the open and closed mouth were acquired, and MRI scanning parameters were applied. RESULTS: The patients consisted of 946 females (average, 36.6 years old), and 319 males (average, 34.3 years old). In all TMD patients, 945 had symptoms in the unilateral temporomandibular joint (TMJ) and 320 in the bilateral TMJ. There were significant differences in the distribution of disk positions based on age, regardless of gender, in the unilaterally and bilaterally symptomatic groups; however, the results were not significant in the asymptomatic group. There were significant differences with respect to the distribution of disk positions between males and females in asymptomatic group and in the unilaterally symptomatic group, although the bilaterally symptomatic group did not show significant differences in this regard. As regards the disk positions in the joints of the three groups (asymptomatic group, unilaterally and bilaterally symptomatic groups), there were significant interactive effects of disk positions, regardless of gender. There were statistically significant age-related differences in disk deformities in all symptom groups, regardless of gender, except for in the group of males lacking symptoms in either joint. As regards disk deformities among the three groups studies here, there were significant interactive effects for disk positions, regardless of gender.

DOI： 10.2174/1874210600903010001

Diagnostic value of dynamic contrast-enhanced MRI in the salivary gland tumors. 国際誌

Miki Hisatomi, Jun-ichi Asaumi, Yoshinobu Yanagi, Teruhisa Unetsubo, Yuu Maki, Jun Murakami, Hidenobu Matsuzaki, Yasutoshi Honda, Hironobu Konouchi

Oral oncology 43 ( 9 ) 940 - 7 2007年10月

記述言語：英語掲載種別：研究論文（学術雑誌）

To evaluate the diagnostic value of dynamic contrast-enhanced MRI (DCE-MRI) in salivary gland tumors, thirty-five patients (47 lesions) who underwent MR examinations and were histopathologically diagnosed with salivary gland tumors in Okayama University Hospital, between April 1998 and March 2005, were entered in the present study. The parameters included CI(max300) or CI(max600), which was the contrast index (CI) at maximal contrast enhancement upon 300 s or 600 s, and Tmax, which was the time that corresponded to the CI(max300). Washout ratio (WR(300) or WR(600)) was defined as follows: CI(max300)-CI(300s)/CI(max300) or CI(max600)-CI(600s)/CI(max600)x100 (%), where CI(300) or CI(600) was the CI at 300s or 600s after contrast medium administration. We obtained the following results from the analysis of DCE-MRI parameters; (a) The salivary gland tumors were categorized into three CI curve types according to Tmax and WR300; Pleomorphic adenoma; Tmax > 210 s and WR300 < 10%, Warthin tumor; Tmax < 60 s and WR300 > 40%, and malignant tumor; 60s < Tmax < 210 s and 10% < WR300 < 30%; (b) On the basis of the relationship between Tmax and CImax or WR, all pleomorphic adenomas were successfully differentiated from Warthin tumor lesions. Of the 20 pleomorphic adenomas, 18 (90.0%) were successfully differentiated from malignant tumors. All Warthin tumor lesions were successfully differentiated from pleomorphic adenomas and malignant tumors. Of 12 the malignant tumors, 11 (91.7%) were successfully differentiated from pleomorphic adenomas. All malignant tumors were successfully differentiated from Warthin tumors. Thus, DCE-MRI parameters are useful in diagnosing salivary gland tumors on the basis of the combined assessment of Tmax and CImax or WR.

DOI： 10.1016/j.oraloncology.2006.11.009

Enhancement effects of test injection with a small amount of MR contrast medium in the oral and maxillofacial region. 国際誌

Yoshinobu Yanagi, Jun-ichi Asaumi, Hironobu Konouchi, Miki Hisatomi, Hidenobu Matsuzaki, Jun Murakami, Yuu Maki, Teruhisa Unetsubo, Kanji Kishi

European journal of radiology 59 ( 3 ) 367 - 70 2006年9月

記述言語：英語掲載種別：研究論文（学術雑誌）

PURPOSE: To examine whether the signal intensity of dynamic contrast-enhanced MRI (DCE-MRI) is altered by test injection of 1 ml of contrast medium, and if so, whether this change affects the DCE-MRI analysis. MATERIALS AND METHODS: Six healthy volunteers were examined by DCE-MRI using a Magnevist syringe and/or an Omniscan syringe for the injection of contrast medium. Each scan was performed 10 times using steady-state free precession (3D-FISP), a sequence for DCE-MRI, before and after intravenous injection of 1 ml of the contrast medium. The internal pterygoid muscle, masseter muscle, tongue, parotid gland, submandibular gland, bone marrow of the mandible, subcutaneous adipose tissue, and common carotid artery were determined to be regions of interest (ROI), and the ROI internal average signal intensity was measured. The 10 data sets obtained before or after contrast medium administration for each ROI were evaluated using the paired t-test. RESULTS: The test injection increased the signal intensities of six of eight ROIs, with all 20 experiments in the submandibular gland showing significant differences. There was no significant difference in the two ROIs corresponding to the carotid artery and subcutaneous adipose tissue of the cheek. CONCLUSIONS: The enhanced signal intensity in the tissue might have been caused by the small amount of contrast medium in the test injection. To eliminate this discrepancy caused by the test injection, a pre-contrast scan should be performed when the average signal intensity of an ROI is measured. We therefore believe that the data obtained before a test injection may be important in the analysis of DCE-MRI.

DOI： 10.1016/j.ejrad.2006.03.017

Usefulness of contrast enhanced-MRI in the diagnosis of unicystic ameloblastoma. 国際誌

Hironobu Konouchi, Jun-ichi Asaumi, Yoshinobu Yanagi, Miki Hisatomi, Noriko Kawai, Hidenobu Matsuzaki, Kanji Kishi

Oral oncology 42 ( 5 ) 481 - 6 2006年5月

記述言語：英語掲載種別：研究論文（学術雑誌）

The radiographic features of unicystic ameloblastoma (UA) are typically unilocular and round area of radiolucency. Therefore, this type of lesion is often misdiagnosed as an odontogenic keratocyst or a dentigerous cyst. UA should be differentiated from odontogenic cysts because the former have a higher rate of recurrence than the latter. In the present study, we performed contrast enhanced-MRI (CE-MRI) to diagnose 13 cases of unilocular, round radiolucent lesions visualized on panoramic radiograph and/or CT. In the cases of UA, low signal intensity was observed on T1-weighted images (WIs), and a markedly high signal intensity was observed on T2-WIs; moreover, relatively thick rim-enhancement with/without small intraluminal nodules was observed upon CE-T1WIs. CE-MRI was considered useful in the diagnosis of UA, as characteristic features of this type of lesion i.e., thick enhancement of the tumor wall and small intraluminal nodules were detected only by CE-MRI in the present study.

Role of O6-methylguanine-DNA methyltransferase and effect of O6-benzylguanine on the anti-tumor activity of cis-diaminedichloroplatinum(II) in oral cancer cell lines. 国際誌

Yu Maki, Jun Murakami, Jun-ichi Asaumi, Hidetsugu Tsujigiwa, Hitoshi Nagatsuka, Susumu Kokeguchi, Kazuhiro Fukui, Noriko Kawai, Yoshinobu Yanagi, Masahiro Kuroda, Noriaki Tanaka, Nagahide Matsubara, Kanji Kishi

Oral oncology 41 ( 10 ) 984 - 93 2005年11月

記述言語：英語掲載種別：研究論文（学術雑誌）

The DNA repair enzyme O6-methylguanine-DNA methyltransferase (MGMT) modulates the effectiveness of alkylating agents. However, the relationship between MGMT and the sensitivities to other agents has not been explored. In the present study, the association between MGMT expression and the cellular sensitivity to the platinum agent, CDDP was examined in four human oral cancer cell lines. CDDP depleted MGMT protein and mRNA levels in all four cell lines. Two cell lines with low MGMT expression were sensitive to an alkylating agent, N-methyl-N'-nitro-N-nitrosoguanidine and CDDP, whereas two other cell lines with high MGMT expression were resistant to both agents. Furthermore, the addition of the MGMT inhibitor, O6-benzylguanine (O6-BG), invariably enhanced CDDP sensitivity. CDDP depleted MGMT expression, and CDDP sensitivity was enhanced by O6-BG. These results provide valuable information about the relationship between MGMT expression and CDDP sensitivity in oral cancer chemotherapy.

Assessment of ameloblastomas using MRI and dynamic contrast-enhanced MRI. 国際誌

Jun-ichi Asaumi, Miki Hisatomi, Yoshinobu Yanagi, Hidenobu Matsuzaki, Yong Suk Choi, Noriko Kawai, Hironobu Konouchi, Kanji Kishi

European journal of radiology 56 ( 1 ) 25 - 30 2005年10月

記述言語：英語掲載種別：研究論文（学術雑誌）

We retrospectively evaluated magnetic resonance images (MRI) and dynamic contrast-enhanced MRI (DCE-MRI) of ameloblastomas. MRI and DCE-MRI were performed for 10 ameloblastomas. We obtained the following results from the MRI and DCE-MRI. (a) Ameloblastomas can be divided into solid and cystic portions on the basis of MR signal intensities. (b) Ameloblastomas show a predilection for intermediate signal intensity on T1WI, high signal intensity on T2WI, and well enhancement in the solid portion; they also show a homogeneous intermediate signal intensity on T1WI and homogeneous high signal intensity on T2WI, and no enhancement in the cystic portion. (c) The mural nodule or thick wall can be detected in ameloblastomas lesions. (d) CI curves of ameloblastomas show two patterns: the first pattern increases, reaches a plateau at 100-300 s, then sustains the plateau or decreases gradually to 600-900 s, while the other increases relatively rapidly, reaches a plateau at 90-120 s, then decreases relatively rapidly to 300 s, and decreases gradually thereafter. There was no difference in the CI curve patterns among primary and recurrent cases, a case with glandular odontogenic tumor in ameloblastoma or among histopathological types such as plexiform, follicular, mixed, desmoplastic, and unicystic type.

Effects of histone deacetylase inhibitor FR901228 on the expression level of telomerase reverse transcriptase in oral cancer. 国際誌

Jun Murakami, Jun-ichi Asaumi, Noriko Kawai, Hidetsugu Tsujigiwa, Yoshinobu Yanagi, Hitoshi Nagatsuka, Tetsuyoshi Inoue, Susumu Kokeguchi, Shoji Kawasaki, Masahiro Kuroda, Noriaki Tanaka, Nagahide Matsubara, Kanji Kishi

Cancer chemotherapy and pharmacology 56 ( 1 ) 22 - 8 2005年7月

記述言語：英語掲載種別：研究論文（学術雑誌）

We speculated whether or not the expression level of telomerase reverse transcriptase (hTERT) would be modulated by agents targeting epigenetics in oral cancer cell lines. Although hTERT is known to be targeted by epigenetic changes, it remains unclear how chemoagents targeting epigenetics work on hTERT transcription. In the present study, the epigenetic effects of the histone deacetylase (HDAC) inhibitor FR901228 on hTERT transcription in oral cancer cell lines were analyzed by RT-PCR. The mRNA expression of hTERT was upregulated after exposure to FR901228 in hTERT-negative Hep2 cells, and even SAS and KB cells expressed high levels of hTERT. Moreover, cotreatment of protein synthesis inhibitor cycloheximide (CHX) resulted in the induction of hTERT transcription by FR901228. This suggests that the induction of hTERT by FR901228 requires de novo protein synthesis to some extent and is more likely a direct than an indirect effect on epigenetic changes such as histone acetylation/deacetylation. We further examined the effect of FR901228 on c-myc protein, which is one of the main hTERT transcription activators. FR901228 repressed c-myc protein only in the absence of CHX, and depended on the enhancement of de novo protein synthesis. Our results indicate that c-myc protein is repressed indirectly by FR901228 but may not contribute to FR901228-induced hTERT transcription. The present study showed that the HDAC inhibitor FR901228 induced the hTERT gene by a complex mechanism that involved transcription factors other than c-myc, in addition to inhibition of histone deacetylation.

Assessment of MRI and dynamic contrast-enhanced MRI in the differential diagnosis of adenomatoid odontogenic tumor. 国際誌

Jun-ichi Asaumi, Yoshinobu Yanagi, Hironobu Konouchi, Miki Hisatomi, Hidenobu Matsuzaki, Hiroshi Shigehara, Kanji Kishi

European journal of radiology 51 ( 3 ) 252 - 6 2004年9月

記述言語：英語掲載種別：研究論文（学術雑誌）

The radiographical differentiation of adenomatoid odontogenic tumor (AOT) from dentigerous cysts, calcifying odontogenic cysts, calcifying epithelial odontogenic tumors, odontogenic keratocysts and amelobastomas is sometimes difficult. We attempted to differentiate AOT from other lesions similar to AOT in radiographic findings using MRI. The MRI features of AOT in our three cases included homogeneous low SI in the cystic portion and homogeneous intermediate SI in the solid portion on T1WI, homogeneous high SI in the cystic portion and intermediate to slightly high SI in the solid portion on T2WI and enhancement of only the solid portion on CE-T1WI although none of the sequences included SI of calcifications. The contrast index curves in the three cases of AOT showed a gradual increase to 300 s, which signified a benign tumor. These MRI features were characteristic features of AOT and might be a basis for differentiating AOT from the above possible lesions in radiographic examinations.

DOI： 10.1016/j.ejrad.2003.09.009

Effects of demethylating agent 5-aza-2(')-deoxycytidine and histone deacetylase inhibitor FR901228 on maspin gene expression in oral cancer cell lines. 国際誌

Jun Murakami, Jun-Ichi Asaumi, Yuu Maki, Hidetsugu Tsujigiwa, Masahiro Kuroda, Noriyuki Nagai, Yoshinobu Yanagi, Tetsuyoshi Inoue, Shoji Kawasaki, Noriaki Tanaka, Nagahide Matsubara, Kanji Kishi

Oral oncology 40 ( 6 ) 597 - 603 2004年7月

記述言語：英語掲載種別：研究論文（学術雑誌）

Maspin, which belongs to the serine protease inhibitor (serpin) superfamily, has been proposed as a potent tumor suppressor that inhibits cell motility, invasion, angiogenesis, and metastasis. In the present study, we examined the effects of 5-aza-2(')-deoxycytidine (5-aza-dC), a demethylating agent, and FR901228, a histone deacetylase (HDAC) inhibitor, on maspin expression in oral cancer cell lines. The expression levels of maspin mRNA were divided into two groups, which was the maspin low-expressed and high-expressed cell lines in the 12 oral cancer cell lines. The maspin promoter contained only a few methylated CpG sites in the maspin low-expressed cell lines. Moreover, the methylation status was not altered after 5-aza-dC treatment. However, the transcription of the maspin gene was clearly increased following 5-aza-dC treatment in a number of oral cancer cell lines. These results imply that an action of 5-aza-dC is separate from induction of promoter demethylation. Treatment with FR901228 resulted in a time-dependent stimulation of the re-expression of maspin mRNA as early as 4 h after treatment in the maspin downregulated cells. The re-expression of the maspin gene may contribute to the recuperation of biological functions linked to FR901228 such as an inhibitory effect on tumor angiogenesis and cell invasion. These results indicate that maspin and its target genes may be excellent leads for future studies on the potential benefits of FR901228, a HDAC inhibitor, in cancer therapy.

Application of dynamic contrast-enhanced MRI to differentiate malignant lymphoma from squamous cell carcinoma in the head and neck. 国際誌

Jun-Ichi Asaumi, Yoshinobu Yanagi, Hironobu Konouchi, Miki Hisatomi, Hidenobu Matsuzaki, Kanji Kishi

Oral oncology 40 ( 6 ) 579 - 84 2004年7月

記述言語：英語掲載種別：研究論文（学術雑誌）

Because malignant lymphoma, the second most common malignant tumor of the head and neck, and squamous cell carcinoma (SCC), the most common malignant tumor of the head and neck, require different treatments, it is important to be able to differentiate them. In the present study, we attempted to differentiate malignant lymphomas from SCCs using dynamic contrast-enhanced MRI (DCE-MRI). Seventeen lesions (in 8 cases) of malignant lymphoma and 30 cases of SCC were compared by DCE-MRI. Thirteen of 17 malignant lymphomas (76.5%) showed the maximum contrast index (CI) at 90-180 s, while 26 of 30 SCCs (86.7%) showed the maximum CI at a much faster 60-105 s. There was a statistically significant difference between SCC and malignant lymphoma in the time needed reach the maximum CI (p = 0.0177). There was also significant difference between SCC and malignant lymphoma in their maximum CIs (p < 0.001), with the maximum CIs of 29/30 SCCs (96.7%) above 2.0, while 12/17 malignant lymphomas (70.6%) showed CIs of less than 2.0. We consider these findings to be useful for distinguishing lymphomas from SCCs.

The value of dynamic contrast-enhanced MRI in diagnosis of malignant lymphoma of the head and neck. 国際誌

Jun-ichi Asaumi, Yoshinobu Yanagi, Miki Hisatomi, Hidenobu Matsuzaki, Hironobu Konouchi, Kanji Kishi

European journal of radiology 48 ( 2 ) 183 - 7 2003年11月

記述言語：英語掲載種別：研究論文（学術雑誌）

In this study, we attempted to diagnose malignant lymphoma on the basis of magnetic resonance imagings (MRIs) and dynamic contrast-enhanced MRI (DCE-MRI). Eighteen lesions (in eight patients), all of which had been proven histopathologically, were detected on MRI. The eight patients included five patients with diffuse large B-cell lymphoma, one with B-cell low-grade MALT lymphoma, one with follicular lymphoma, and one with Hodgkin's lymphoma. Nine lesions were located in the submandibular region, three in the buccal region, two in the orbit region, two in the submental region, and one each in the palatal and tonsil regions. The diameter of the lesions ranged between 9 and 42.2 mm (average: 22.4 mm). The signal intensities (SIs) of the 18 lesions were examined on T1-weighted (T1WI), T2WI, and gadopentetate (Gd)-T1WI. One lesion in case 8 was excluded from DCE-MRI findings, i.e., the regions of interest could not be adequately set on DCE-MRIs. The contrast index (CI) curves of the remaining 17 lesions were prepared. All 18 lesions showed almost the same images on T1WI, T2WI, and Gd-T1WI, although they represented four types of lymphoma. The images showed homogeneous SI that was intermediate to slightly high SI on T1WI, slightly high SI on T2WI, and moderately enhanced on Gd-T1WI. Thus, the cases of malignant lymphoma in this study showed relatively characteristic features based on MRI; however, these features might be non-specific. The CI curves in this study showed a relatively rapid increase, reaching a maximum CI at 45-120 s, and a relatively rapid decrease in most lesions (14/17; 82.4%); on the other hand, the curves of 3 of the 15 lesions (17.6%) showed relatively rapid increase, sustenance of a plateau, and a gradual decrease thereafter. These patterns of CI curves may indicate characteristic features useful for distinguishing malignant lymphomas from other lesions.

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