PubMed Health⌕ Search

Biomedical subjects

T Amagasa

Publications and source records attributed to T Amagasa.

At least 19 recordsLinked to original sources
PubMed2006

A potential pitfall of MR imaging for assessing mandibular invasion of squamous cell carcinoma in the oral cavity.

BACKGROUND AND PURPOSE: Whether MR imaging is superior to CT in evaluating the presence and extent of mandibular invasion by squamous cell carcinoma remains controversial. The purpose of this study was to directly compare the diagnostic accuracy of MR imaging and that of CT. METHODS: MR and CT images in 51 patients with squamous cell carcinoma of the oral cavity were evaluated for the presence and extent of mandibular invasion. The results were correlated with histopathologic findings. RESULTS: Twenty-five of 51 patients had histopathologic evidence of mandibular cortical invasion. The tumor involved both the cortex and the bone marrow in all 25 patients and involved the inferior alveolar canal in 5 patients. The sensitivity and specificity for mandibular cortical invasion were 96% and 54% for MR imaging and 100% and 88% for CT, respectively. Those for inferior alveolar canal involvement were 100% and 70% for MR imaging and 100% and 96% for CT, respectively. In both evaluations, the specificity of MR imaging was significantly lower than that of CT (McNemar test, P = .004 in the former and P = .002 in the latter). Chemical shift artifact by bone marrow fat was postulated to be the source of most false-positive cases on MR imaging findings for mandibular cortical invasion. Those for inferior alveolar canal involvement were due to MR imaging visualization of the tumor and surrounding inflammation with similar signal intensity. CONCLUSION: In assessing the presence and extent of mandibular invasion by squamous cell carcinoma, the specificity of MR imaging was significantly lower than that of CT.

Adult↗
PubMed2005

The comparison between pains, difficulties in function, and associating factors of patients in subtypes of temporomandibular disorders.

The aim of this study was to compare the multidimensional properties among subtypes of painful temporomandibular disorders (TMD): myofascial pain (group I), disc displacement (group II), arthralgia (group IIIa) and osteoarthritis (group IIIb). A total of 511 patients answered a battery of questionnaires, which included questions relating to intensity and duration of pain, the Japanese version of the McGill Pain Questionnaire, limitation of daily functions, the Hospital Anxiety and Depression Scale, the Eysenck Personality Questionnaire short-form and 34 items of behavioural contributing factors. Group IIIb showed significantly the highest age in all subtypes. Those in group I had higher depression scores than those in group II (P = 0.005). Group IIIa had a lower women's ratio than in group II (P = 0.001) and the patients showed a shorter pain duration than those in groups I (P = 0.000) and II (P = 0.001). Group IIIa patients also showed lower visual analogue scale (VAS) ratings for pain descriptors 'heavy' (P = 0.002) and 'tiring' (P = 0.004) than those of group I, and 'dull' (P = 0.005), 'heavy' (P = 0.001) and 'tiring' (P = 0.005) than those of group II. Group IIIa showed lower ratios of contributing factors of 'an awareness of grinding/clenching during sleep' (P = 0.000) and 'an awareness of clenching sensation when waking up at night' (P = 0.002) than those of group I, and also showed a higher ratio of 'a liking for a hard food' (P = 0.000) and lower ratio of 'talking for a long time on the telephone' (P = 0.001) than those of group II. In conclusion, although several properties were different between subtypes, the majority of them were similar in the four subtypes of TMD.

Activities of Daily Living↗
PubMed2004

Primary malignant melanoma of the oral cavity: assessment of outcome from the clinical records of 35 patients.

Oral malignant melanoma is extremely rare and carries a poor prognosis. The treatment of choice remains controversial. We retrospectively studied 35 patients with primary malignant melanoma of the oral cavity between 1970 and 2001 to define the clinical features of this disease and evaluate treatment methods. The main variables studied were clinical findings, response to therapy, and outcome. Surgery with complete macroscopic resection was performed at the primary site in 13 patients (surgery group) and radiotherapy was done without surgery in 17 (non-surgery group). The 5-year cumulative survival rate was 15.4% in the surgery group, 35.3% in the non-surgery group, and 21.8% overall. Distant metastasis was present in 64.7% (11/17) of the non-surgery group and 76.9% (10/13) of the surgery group. Improved outcome in oral malignant melanoma requires the development of new therapies and the prevention of distant metastasis.

Adult↗
PubMed2004

Role of gene E2f1 in susceptibility to bacterial adherence of oral streptococci to tooth surfaces in mice.

Dental plaque is composed of a biofilm community of microorganisms on teeth that coats the oral cavity, including attaching to the teeth, and provides a protective reservoir for oral microbial pathogens, which are the primary cause of persistent and chronic infectious diseases. Oral streptococci are pioneering organisms that play an important role in biofilm formation on tooth surfaces as well as being primary causative agents of dental caries. The purpose of this study was to clarify the role of the E2f1 gene in susceptibility to dry mouth and bacterial adherence of oral streptococci to tooth surfaces in animal model experiments. A mutation of the E2f1 gene in mice is known to cause enhanced T-lymphocyte proliferation, leading to testicular atrophy, splenomegaly, salivary gland dysplasia, and other systemic and organ-specific autoimmunity. We found a decreased volume of saliva production and protein production rate, along with increased amylase activity, IgA concentration, and mucin 1 concentration in E2F-1(-/-) mice as compared with the control C57BL/6 mice. Further, we quantified the recolonization of oral streptococci in E2F-1(-/-) mice and found that a higher number of some oral streptococci were colonized on the teeth of these mice. In particular, following oral ingestion of 1% sucrose in water, the colonization of Streptococcus mutans increased in comparison with other streptococci. Our results suggest that the E2f1 gene may affect susceptibility for oral biofilm formation by streptococci in humans with dry mouth.

Animals↗
PubMed2003

Establishment of tendon-derived cell lines exhibiting pluripotent mesenchymal stem cell-like property.

Development of the musculoskeletal system requires coordinated formation of distinct types of tissues, including bone, cartilage, muscle, and tendon. Compared to muscle, cartilage, and bone, cellular and molecular bases of tendon development have not been well understood due to the lack of tendon cell lines. The purpose of this study was to establish and characterize tendon cell lines. Three clonal tendon cell lines (TT-E4, TT-G11, and TT-D6) were established using transgenic mice harboring a temperature-sensitive mutant of SV40 large T antigen. Proliferation of these cells was significantly enhanced by treatment with bFGF and TGF-beta but not BMP2. Tendon phenotype-related genes such as those encoding scleraxis, Six1, EphA4, COMP, and type I collagen were expressed in these tendon cell clones. In addition to tendon phenotype-related genes, expression of osteopontin and Cbfal was observed. These clonal cell lines formed hard fibrous connective tissue when implanted onto chorioallantoic membrane in ovo. Furthermore, these cells also formed tendon-like tissues when they were implanted into defects made in patella tendon in mice. As these tendon cell lines also produced fibrocartilaginous tissues in tendon defect implantation experiments, mesenchymal stem cell properties were examined. Interestingly, these cells expressed genes related to osteogenic, chondrogenic, and adipogenic lineages at low levels when examined by RT-PCR. TT-G11 and TT-E4 cells differentiated into either osteoblasts or adipocytes, respectively, when they were cultured in cognate differentiation medium. These observations indicated that the established tendon cell line possesses mesenchymal stem cell-like properties, suggesting the existence of mesenchymal stem cell in tendon tissue.

Adipocytes↗
PubMed2003

Maxillary bone invasion by gingival carcinoma as an indicator of cervical metastasis.

OBJECTIVES: To evaluate the significance of maxillary bone invasion by gingival carcinoma as an indicator of cervical metastasis. METHODS: Twenty-one patients with squamous cell carcinoma of the upper gingiva were included in the study. The extent of bone invasion was assessed by dental CT. Six patients had cervical metastases at the initial examination and eight more developed them during the 2-year follow-up period. The relationship of cervical metastases with age and gender of these patients, as well as with the size of the lesion and extent of bone invasion, was examined by logistic multivariate regression analysis. RESULTS: There was a significant relationship between the presence of bone invasion and the presence of cervical metastasis (P<0.05). CONCLUSIONS: Maxillary bone invasion is an indicator of cervical metastasis in gingival carcinoma.

Adult↗
PubMed2002

Topographical analysis of lymphatic pathways from the meso- and hypopharynx based on minute cadaveric dissections: possible application to neck dissection in pharyngeal cancer surgery.

To facilitate the development of new operative procedures for pharyngeal cancer, it is important to understand the precise location of the lymph nodes and their pathways. Minute dissection of 22 neck-halves (11 adult cadavers) was undertaken to determine the location and topographical relationships of the lymphatics of the pharynx. Four groups of lymph nodes on the drainage pathways from the meso- and hypopharynx to the internal jugular nodes were classified according to their topographical relationships to the carotid arteries: lateral pharyngeal, superior thyroid, lateral retropharyngeal and medial retropharyngeal nodes. Lymphatics from the mesopharynx passed laterally to lateral pharyngeal or jugulodigastric nodes or slightly upward to lateral retropharyngeal nodes. Lymphatic drainage from the hypopharynx was multidirectional with the pathways being classified as follows: ascending pathway to the lateral pharyngeal and lateral retropharyngeal nodes, lateral pathway to the internal jugular chain, and descending pathway connecting to the uppermost vessels ascending from the recurrent laryngeal nerve chain. In addition, a contralateral pathway was found originating from the hypopharynx extending to the contralateral internal jugular chain. These findings provide valuable information for comparison with CT and MRI studies, as well as with clinicopathological data, to clarify the precise mode of metastasis in head and neck cancers. These results are also applicable to neck dissection in meso- and hypopharyngeal cancers.

Aged↗
PubMed2002

Regulation of cell motility via high and low affinity autocrine motility factor (AMF) receptor in human oral squamous carcinoma cells.

A tumour-secreted cytokine autocrine motility factor (AMF) induces in vivo invasion and metastasis, and in vitro tumour cell motility by a signal transduction through interaction with its cell surface receptor gp78. In this report, we investigated the characterization of a high-metastatic human oral squamous cell carcinoma (SCC) cell line LMF4 and low-metastatic HSC-3 in comparison with non-metastatic HSC-2 and HSC-4. Morphological and motility analyses revealed LMF4 cells to have the highest motile activity among those cells. However, LMF4 cells shared the similar features with HSC-3: high level secretion of AMF, enhancement of gp78 expression, co-expression of vimentin and cytokeratin, although LMF4 cells showed twice as high motile reactivity as HSC-3. The only difference was that LMF4 had twice as high amount of low-affinity receptor(s) as HSC-3, shown by Scatchard analysis.

Blotting, Northern↗
PubMed2002

Mandibular bone invasion by gingival carcinoma on dental CT images as an indicator of cervical lymph node metastasis.

OBJECTIVES: To evaluate the significance of mandibular bone invasion by gingival carcinoma revealed by reformatted dental CT images as a prognostic indicator of cervical metastasis. METHODS: Thirty-two patients with squamous cell carcinoma of the lower gingiva were examined by dental CT. Cervical metastases and survival rates of these patients were analysed in relation to their clinical characteristics, histologic grading based on gingival biopsy, and mandibular bone invasion using reformatted dental CT imaging diagnoses prior to surgery. The dental CT images were classified into four types: Class I, no bone invasion; Class II, invasion confined to the alveolus; Class III, invasion extending between the alveolus and the mandibular canal; and Class IV, invasion beyond the mandibular canal. RESULTS: Logistic multivariate regression analysis showed that bony invasion identified on dental CT images was a significant prognostic factor in cervical metastases (P=0.028). The 5-year overall survival rates of Classes I, II, III, and IV were 100% (n=9), 76.2% (n=9), 71.4% (n=7), and 28.6% (n=7), respectively. CONCLUSIONS: The evaluation of mandibular bone invasion using dental CT images is useful as a prognostic indicator of cervical metastasis for patients with gingival carcinoma.

Adult↗
PubMed2001

Intracellular apoptosis-inducing factor is induced by a vacuolar type H+-ATPase inhibitor in B lineage cells.

We previously reported that concanamycin A, a specific inhibitor of vacuolar type H+-ATPases, induces DNA fragmentation in B cell hybridoma HS-72 cells. In the present study, we found that the cytosol from concanamycin A-treated HS-72 cells had a cytotoxic effect on intact cells in a cell viability assay. While activin A also induced apoptosis in HS-72 cells, the cytosol from activin A-treated HS-72 cells had no effect on cell viability. We purified the cytosol from concanamycin A-treated HS-72 cells by a four-step procedure: ultracentrifugation; HiTrap heparin column chromatography; HiTrap Q column chromatography; and reverse-phase high performance liquid chromatography on a C18 hydrophobic support. The biologically active fraction, which was used as partially purified cytosol, gave a specific band of protein with a molecular mass of 33 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The mechanism of cell death was examined by observing changes in nuclear morphology, an increase in the proportion of fragmented DNA, and the typical ladder pattern of degraded chromosomal DNA, indicating the induction of apoptosis in cells cultured with the partially purified cytosol. The overexpression of human Bcl-2 suppressed apoptosis, indicating that the cytosol from concanamycin A-treated HS-72 cells induces apoptosis by a Bcl-2-inhibiting mechanism. These findings suggest that concanamycin A, a vacuolar type H+-ATPase inhibitor, produces intracellular apoptosis-inducing factor in B cell hybridoma.

Animals↗
PubMed2001

Clinicopathological study of carcinomas of the lip and the mucosa of the upper and lower lips.

BACKGROUND: Lip carcinomas are rare oral tumors, and there have been few reports of lip carcinoma in Japan. METHODS: Of 914 patients with oral carcinomas treated between January 1980 and December 1998, 12 (1.3%) had lip carcinoma and 5 (0.5%) had lip mucosal carcinoma. We investigated the clinicopathological features of these 17 patients. RESULTS: Of the 12 patients with carcinoma of the lip, 10 had squamous cell carcinomas (9, external lower lip; 1 commissures) and 2 had mucoepidermoid carcinomas (external upper lip). Of the 5 patients with lip mucosal carcinoma, 3 had squamous cell carcinomas (2, mucosa of the lower lip; 1, mucosa of the upper lip), 1 had mucoepidermoid carcinoma (mucosa of the lower lip), and 1 had acinic cell carcinoma (mucosa of the lower lip). Of the 12 patients with lip carcinoma, 9 were classified as stage I, 2 as stage II, and 1 as stage III; all 5 of the patients with lip mucosal carcinoma were stage I. Five patients with lip carcinoma were treated by resection, 5 by a combination of resection and reconstruction, and 2 by radiotherapy alone. All patients with lip mucosal carcinoma were treated by resection. After the initial therapy, 3 patients without neck dissection had regional recurrences and received delayed neck dissection, and 2 died with neck regional recurrence after dissection. The 5-year cumulative survival rates of the patients with lip carcinoma and those with lip mucosal carcinoma were 82.5% and 80.0%, respectively. CONCLUSION: We suggest that early-stage carcinomas of the lip and of the mucosa of the upper and lower lips are frequent, and we found that the outcome of these patients was excellent. However, an aggressive therapeutic approach to the lip carcinoma patient with cervical metastasis appears warranted, in an attempt to improve locoregional control and ultimate survival.

Aged↗
PubMed2001

Homozygous deletions on the short arm of chromosome 3 in human oral squamous cell carcinomas.

Recent cytogenetic and allelic deletion analyses have demonstrated that deletions on the short arm of chromosome 3 (3p) are frequently found in various cancers, including oral squamous cell carcinomas (OSCCs). This suggests that one or more tumor suppressor gene(s) for these malignancies might be located on 3p. In the present study, to further define the region(s) on 3p that harbor putative tumor suppressor gene(s) for OSCCs, we have investigated the existence of homozygous deletions (HDs) at 34 loci on 3p, in 14 OSCC cell lines. HDs were detected within the FRA3B region at 3p14.2 in only two cell lines (HSC-4 and TSU). Recently, the human fragile histidine triad (FHIT) gene was isolated from this region, abnormalities of which have been found at high frequencies in several types of human cancers. We also examined the expression of the FHIT gene, using reverse transcription-polymerase chain reaction (RT-PCR) and exon-specific PCR, in the two OSCC cell lines which showed HDs at 3p14.2. There was no detectable expression of exon 5, which was the first protein-coding exon of FHIT gene, in HSC-4 cells, indicating that this region was homozygously deleted in this cell line. On the other hand, HD in the TSU cells did not affect the coding region of the FHIT gene, and the wild-type transcript was detected by RT-PCR. Therefore, several candidate tumor suppressor genes, including the FHIT gene, may reside in these homozygously deleted regions. To our knowledge, this is the first report of HDs on 3p in OSCCs.

Acid Anhydride Hydrolases↗
PubMed2001

High-resolution magnetic resonance imaging of squamous cell carcinoma of the tongue: an in vitro study.

OBJECTIVES: To determine in vitro the potential of high-resolution MRI for evaluating the depth of tumor invasion of the tongue. METHODS: Twenty-one resected specimens of squamous cell carcinoma of the tongue were examined on a 1.5T MRI system with a 4 cm surface coil using four different sequences; T1W SE, T2W SE, 3D-FISP and 3D-CISS. The thickness of normal epithelium, tumor depth and width were measured on both MR images and histopathological sections. RESULTS: The mucosal epithelium, lamina propria and muscles of the tongue were clearly identifiable on MRI. All 21 carcinomas, including three early invasive carcinomas, were clearly demonstrated. A high correlation was found between the values measured by MRI and histopathology for thickness of mucosal epithelium and both depth and width of tumors. There was a good agreement between the T2W SE and the other imaging sequences for measurements of both depth and width of tumors. CONCLUSION: High-resolution MR imaging appears reliable for the in vitro evaluation of depth of tumor invasion in carcinoma of the tongue.

Adult↗
PubMed2001

Diagnostic accuracy of computed tomography for cervical metastases at different anatomical levels in carcinoma of the tongue.

OBJECTIVES: To evaluate the variation in diagnostic accuracy of CT in the assessment of cervical lymph node metastases from tongue carcinoma at different anatomical levels. METHODS: Sixty-one patients with squamous cell carcinoma of the tongue who underwent radical neck dissection were included in this study. The CT and histopathological findings at nodal levels I-V were compared for the presence or absence of lymph node metastases. Sensitivity, specificity, negative predictive value (NPV) and positive predictive value (PPV) of CT were evaluated for each nodal level. RESULTS: The sensitivity of CT was: level I, 85%; level II, 77.8%; level III, 53.3%; level IV, 66.7% and level V, 25%. There was a significant difference in the sensitivity between the level I-II group (80.9%) and level III-V group (53.6%) (P=0.012). There was no significant difference in the specificity, NPV, and PPV between the two groups. CONCLUSIONS: The sensitivity of CT in detecting cervical lymph node metastases was significantly smaller at levels III-V than at levels I-II.

Adult↗
PubMed2001

Osteopontin deficiency reduces experimental tumor cell metastasis to bone and soft tissues.

Osteopontin has been implicated in the metastasis of tumors, and human tumors with high metastatic activity often express osteopontin at high levels. Osteopontin contains an arginine-glycine-aspartate (RGD) motif that is recognized by integrin family members to promote various cell activities including attachment to substrate and it is abundant in bone, to which certain tumors preferentially metastasize. Therefore, we investigated the role of osteopontin in the experimental metastasis of tumor cells using recently established osteopontin-deficient mice. B16 melanoma cells, which produce little osteopontin, were injected into the left ventricle of osteopontin-deficient mice or wild-type mice. Animals were killed 2 weeks after injection. The number of tumors was reduced in the bones of osteopontin-deficient mice compared with the bones in wild-type mice. The number of tumors in the adrenal gland also was reduced. To investigate the osteopontin effect on metastases via a different route, we injected B16 melanoma cells into the femoral vein. Through this route, the number of lung tumors formed was higher than in the intracardiac route and was again less in osteopontin-deficient mice compared with wild-type mice. In conclusion, in an experimental metastasis assay, the number of tumors found in bone (after intracardiac injection) and lung (after left femoral vein injection) was significantly reduced in osteopontin-deficient mice compared with wild-type mice. Tumor numbers in other organs examined were small and not significantly different in the two situations.

Animals↗
PubMed2001

[A clinical investigation of oro-maxillary sinus-perforation due to tooth extraction].

Oro-maxillary sinus perforation occurs occasionally at the extraction of a maxillary tooth, and it may be a cause of maxillary sinusitis or antro-oral fistula. Our purpose was to investigate the most frequent site of perforation, and to understand the clinical course of patients after perforation. We examined 2,038 maxillary teeth extracted from 1,337 patients (473 males and 864 females) at the First Department of Oral and Maxillofacial Surgery, Tokyo Medical and Dental University, from January 1991 to December 1993. Perforation occurred in 77 of all 2,038 teeth (3.8%). Of these, 38 teeth were from males (38/733; 5.2%), and 39 were from females (39/1,305; 3.0%). The perforation rate was significantly higher in males. Perforation occurred most often with extraction of an upper first molar, and in the third decade of life. The perforation rate gradually decreased with higher age. We classified 38 cases into 3 categories according to panorama X-P: 1) The tip of the root crossed over the bottom line of the maxillary sinus (29 cases), 2) Not crossed over distinctly (4 cases), 3) Just lie on, or whether the tip of the root crossed over the bottom line of the maxillary sinus was not distinct (5 cases). As to treatment, 30 perforations (39.0%) closed spontaneously in the course of observation, irrigation with physiological saline was used in 43 cases (55.8%), radical sinusotomy accompanied by closure of the perforation was performed in 4 cases, and only flap closure was used in 7 cases. There were no cases of relapse.

Adult↗