Biomedical subjects

T Kurabayashi

Publications and source records attributed to T Kurabayashi.

At least 19 recordsLinked to original sources

PubMed2006

Application of magnetic resonance imaging movie to assess articulatory movement.

OBJECTIVE: To introduce the technique of magnetic resonance imaging (MRI) movie and to propose its feasibility for investigating articulatory movement. SUBJECTS: Five healthy adult females participated in the study. METHODS: Dynamic changes in oropharyngeal structures were assessed with MRI movie during the articulation of a bilabial consonant. RESULTS: Movements of the velum and tongue at a time resolution of 30 ms were complex at the tip of the tongue and the anterior part of the velum. These movements that were seen with a time resolution of 30 ms could not be interpolated or in any way derived from the results obtained with a time resolution of 120 ms. CONCLUSION: The results suggest that MRI movie may be useful in the evaluation of articulation. It is important to reduce the time resolution to 30 ms to obtain images of articulators.

Adult↗

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

Association between single nucleotide polymorphisms of estrogen receptor alpha gene and efficacy of HRT on bone mineral density in post-menopausal Japanese women.

BACKGROUND: Although HRT for post-menopausal women can protect against bone loss, variations in bone responses exist. We studied whether single nucleotide polymorphisms (SNP) of the estrogen receptor-alpha (ERalpha) gene contribute to the effect of HRT on lumbar spine bone mineral density (BMD). METHODS: Subjects were 84 post-menopausal women who had been taking HRT for 3 years to treat osteopenia or osteoporosis. Eighteen SNP in the ERalpha gene were characterized by a single nucleotide primer extension assay. RESULTS: Genotyping of the 84 individuals revealed that all SNP were quite common, the minor allele frequency being > or = 20%. A SNP in intron 6 (IVS6+14144) was significantly associated with the response to HRT for the first 3 years after starting treatment (P = 0.043, 0.025 and 0.032 for the first, second and third years respectively). Haplotype analysis revealed that a combination of SNP IVS6+14144 and IVS4+4238 was significantly correlated with the response to HRT; women with haplotype G-G (IVS6 14144-IVS4 4238) showed a significantly higher response (P = 0.014, 0.043 and 0.010 for the first second and third year respectively). CONCLUSIONS: These results suggest that a specific SNP and the haplotype of the selected SNP could be used to predict the effect of HRT on lumbar BMD.

Adult↗

PubMed2005

CT findings as a significant predictive factor for the curability of mandibular osteomyelitis: multivariate analysis.

OBJECTIVES: To re-evaluate computed tomographic (CT) imaging as a diagnostic tool for mandibular osteomyelitis and to assess the clinical significance of CT findings. METHODS: CT images of 78 patients with mandibular osteomyelitis were reviewed. All patients were classified as cured or non-cured. Each CT finding was investigated for frequency, correlation with duration and disease cure. RESULTS: Of the 78 patients, 49 (63%) were classified as "cured" and 29 (37%) as "non-cured". Non-cured had experienced a significantly longer duration of symptoms. The most frequent CT finding was sclerosis and defect in the trabecular bone. Changes of bone width and thickening of the cortical plate were accompanied with longer disease duration. The extent of the diseased area was linearly correlated with the duration of symptoms. The significant factors to discriminate non-cured from cured were the extent of the disease, the number of findings, changes in the bone width, osteosclerosis and thickening of the cortex. Multivariate logistic regression analysis indicated that the extent of the disease and presence of changes in bone width were significant variables correlating with the cure of osteomyelitis. CONCLUSIONS: The extent of disease and the presence of change in bone width shown on CT were significantly correlated with the curability of osteomyelitis. These results indicated the usefulness and importance of CT examination for the diagnosis of mandibular osteomyelitis.

Adolescent↗

PubMed2004

Inhibition of the extracellular signal-regulated kinase (ERK) pathway and the induction of radioresistance in rat 3Y1 cells.

PURPOSE: Activation of the extracellular signal-regulated kinase (ERK) pathway generally results in stimulation of cell growth and confers a survival advantage. However, the potential involvement of this pathway in cellular radiosensitivity remains unclear. The study was designed to examine whether the ERK pathway affects intrinsic radiosensitivity in mammalian cells. MATERIALS AND METHODS: Exponentially growing rat 3Y1 cells were used. A specific inhibitor of mitogen-activated ERK kinase (MEK), PD98059, was used to inhibit the ERK pathway. In addition, kinase-deficient MEK was expressed in cells to inhibit the pathway in a dominant-negative manner. Activation of ERK was visualized by Western blot using an antibody that recognizes the phosphorylated form of ERK. Radiosensitivity was evaluated by a colony-forming assay. RESULTS: 3Y1 cells treated with PD98059 exhibited a significant inhibition of cell proliferation and radiation-induced transient activation of ERK. Unexpectedly, it was found that the inhibitor enhanced clonogenic radioresistance. This effect on radioresistance was confirmed by expression of kinase-deficient MEK. Apoptotic activities following irradiation were significantly inhibited in PD98059-treated cells as determined by caspase-3-like activities. CONCLUSION: Activation of the MEK/ERK pathway increases clonogenic radiosensitivity in rat 3Y1 cells. These findings, together with a variety of other data, suggest that there might be clinical implications in targeting the MEK/ERK pathway in radiotherapy.

Animals↗

PubMed2004

Effects of vitamin D and estrogen receptor gene polymorphisms on the changes in lumbar bone mineral density with multiple pregnancies in Japanese women.

BACKGROUND: Our aims were to follow the longitudinal changes in lumbar spine bone mineral density (BMD) with multiple pregnancies, and to study whether polymorphisms in the vitamin D receptor (VDR) and estrogen receptor (ER) genes may influence the results. METHODS: We repeatedly measured the BMD of the lumbar spine (L2-L4) of 133 women who had undergone two successive pregnancies and 73 non-pregnant controls, and analysed the restriction fragment length polymorphisms using restriction endonucleases TaqI, ApaI and FokI for the VDR gene, and PvuII and XbaI for the ER gene. RESULTS: Cases and controls had no significant differences in the longitudinal BMD changes. The mean percentage change in lumbar BMD (DeltaBMD%) of the women with the XX/Xx genotype was significantly lower than that of the women with the xx genotype after adjusting for age at each delivery, BMD of the first scan, and interval between the scans (0.2 +/- 3.3 versus 2.0 +/- 4.2%; P=0.030, analysis of covariance). Multiple regression analyses to evaluate the contribution of the XbaI polymorphism of the ER gene on DeltaBMD% showed that the percentage decrease in BMD was greater for women lacking the XbaI restriction site (adjusted R2=0.188, P<0.0001). CONCLUSIONS: The present study suggests that the DeltaBMD% was significantly influenced by the XbaI polymorphism of the ER gene.

Adult↗

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↗

PubMed2003

Accuracy of panoramic radiography in assessing the dimensions of radiolucent jaw lesions with distinct or indistinct borders.

OBJECTIVES: To evaluate the accuracy of panoramic radiography (PR) in assessing the dimensions of mandibular lesions. METHODS: One hundred and fifteen cases exhibiting radiolucent lesions in the mandibular premolar, molar or ramus area were selected retrospectively. They were divided into four types: cyst with sclerotic margin (Type I); cyst without sclerotic margin (Type II); ameloblastoma (Type III); or squamous cell carcinoma (Type IV). Maximum mesiodistal length and superoinferior height were measured on PR (Lpmax and Hpmax, respectively) and on CT (Lcmax and Hcmax, respectively) and the results were compared. RESULTS: Correlation coefficients between Lpmax and Lcmax and between Hpmax and Hcmax were high for Type I, II and III lesions but were significantly lower for Type IV lesions. Regression coefficients between Lpmax and Lcmax and between Hpmax and Hcmax were indistinguishable from 1.0 for all types of lesions. The mean relative difference between Lpmax and Lcmax varied from 1.2% to 8.2%. The difference was only -0.3% for larger lesions of combined Types I and II. The mean relative difference between Hpmax and Hcmax varied from--3.5% to 1.1% depending on the type of lesions. CONCLUSION: PR is accurate for assessing the dimensions of radiolucent lesions in the posterior mandible when the margins are well defined.

Adolescent↗

PubMed2002

The effect of multiple pregnancies on lumbar bone mineral density in Japanese women.

OBJECTIVE: To elucidate the effect of multiple pregnancies on lumbar spine bone mineral density (BMD). METHODS: The BMD of the lumbar spines (L2-L4) of 1,113 healthy women was measured within 7 days of childbirth. In addition 113 women had spine BMD measurements after their next delivery. RESULTS: In the cross-sectional study, there was no apparent effect of parity on lumbar BMD. In the longitudinal study, the mean BMD after the next delivery was significantly higher than that after the initial delivery (1.019 +/- 0.115 g/cm(2) vs. 1.006 +/- 0.117 g/cm(2), P = 0.001, paired t test) with a percent change (DeltaBMD%) of 1.4 +/- 4.2%. Multiple regression analysis to identify independent predictors of DeltaBMD% showed a negative correlation with maternal age at the subsequent delivery (P = 0.033) but no correlation of DeltaBMD% with the length of lactation between the scans. CONCLUSION: Multiple pregnancies may not reduce maternal lumbar BMD, although the percentage decrease in BMD was greater in older women at the subsequent delivery. The length of lactation between the scans had no effect on these results.

Body Weight↗

PubMed2002

Successful prenatal treatment of congenital heart block with ritodrine administered transplacentally.

Congenital heart block (CHB) is rather rare, and a poorer prognosis has been documented in fetuses with a ventricular rate <55 beats per minutes (bpm), in which therapeutic interventions during pregnancy have been warranted. We present a case of CHB associated with maternal anti-SSA/Ro antibody, diagnosed at 28 weeks' gestation. Fetal echocardiography revealed atrioventricular dissociation, with an atrial rate of 170 bpm and a ventricular rate of 54 bpm. To increase the fetal heart rate, maternal intravenous ritodrine infusion was undertaken, fetal ventricular rate was rapidly increased to 65 bpm. The pregnancy successfully continued until term, and a female infant weighing 2919 g was delivered by cesarean section with Apgar scores of 8 and 8 and 1 and 5 min. The infant is now 12 months of age and growing normally on oral terbutaline without pacing. In a case of fetal heart block, maternal administration of ritodrine may be a therapeutic intervention to improve the fetal and neonatal prognosis.

Adult↗

PubMed2002

MR imaging of benign and malignant lesions in the buccal space.

OBJECTIVES: To evaluate MRI characteristics of buccal space lesions and to discuss the sensitivity of MRI in predicting malignancy of those lesions. METHODS: Thirty patients with malignant (n=7) or benign (n=23) lesions originating in the buccal space were reviewed retrospectively. MR images were assessed for the margins, internal architecture, signal intensity of lesions and their relation to the surrounding structures. RESULTS: Two cases of soft tissue sarcoma were shown as ill-defined masses with infiltration into adjacent muscles and bone. On the other hand, all tumors of minor salivary gland origin, whether malignant (n=4) or benign (n=2), were well-defined and confined within the buccal fat pad without infiltration into surrounding structures. All haemangiomas (n=9) had very high T2-weighted signal intensity. Three out of them contained signal voids on all sequences thought to represent phleboliths, a finding strongly suggestive of the diagnosis. Inflammatory lesions were characterized by the presence of edema in the surrounding fat. When ill-defined margins, infiltration into muscles and bone destruction were used as the criteria for the malignancy, only two out of seven malignant tumors were correctly diagnosed (sensitivity 29%). CONCLUSIONS: Although MR imaging was useful in demonstrating the extent of buccal space lesions, its diagnostic value in predicting malignancy was very limited. It was especially true for malignant tumors of minor salivary gland origin, which were typically seen as well-defined masses without infiltration into surrounding structures on MRI.

Adipose Tissue↗

PubMed2002

Osteoid osteoma in the mandible.

A case of osteoid osteoma (OO) in the mandible of 26-year-old female is presented. Her main complaint was intermittent pain during a 3 year period. The panoramic radiograph of the mandible showed diffuse sclerosis including an ill-defined circular radiopacity in the molar region. Computed tomography (CT) revealed an osseous lesion of 10 mm diameter that was located in the cortical bone of the mandible. Bone scintigraphy showed a localized region of high uptake of 99mTc HMDP. The lesion was diagnosed as an OO by histopathological examination of the surgical specimen and CT findings. Since radiological appearance has very significant meaning in the differentiation of an OO from other bone forming tumors, CT is the method of choice when the main symptom is pain and the conventional radiography was not informative.

Adult↗

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↗

PubMed2002

Effects of the beta3 adrenergic receptor agonist on developmental obesity in oophorectomized rats.

In this study, we evaluated the anti-obesity effects of selective beta3 adrenergic receptor agonist (ARa) and/or a diet in oophorectomized (OVX) treatment in obese rats. Ten-week-old female Sprague-Dawley rats were divided into 4 groups: (1) OVX; (2) OVX treated with beta3 ARa, BRL 35 135; (3) sham-operated controls (sham group); (4) sham-treated with beta3 ARa (sham+ARa group). These four groups were divided into two groups, one on ad libitum diet, and the other on a diet of limited chow. The effects of beta3 ARa on body weight, intraabdominal fat weight, adipocyte volume, serum lipid content, and serum leptin were measured after 4 weeks had been completed. On both the ad libitum and the limited diet, ARa significantly reduced the ratio of intraabdominal fat and body weight (IAF ratio) regardless whether in the OVX or sham group, although ARa had no influence on weight gain. On the ad libitum diet, the serum leptin was significantly increased after OVX, and significantly reduced after ARa administration. ARa significantly reduced the volume of intraabdominal adipocytes. We conclude that ARa reduces intraabdominal fat without reducing body weight in oophorectomized rats. The serum parameter affected differently to rats on the ad libitum diet and on the limited diet.

Adipocytes↗

PubMed2001

Effects of a beta 3 adrenergic receptor agonist on bone and bone marrow adipocytes in the tibia and lumbar spine of the ovariectomized rat.

The object of this study was to investigate the effects of a b3 adrenergic receptor agonist (ARa) and estrogen on bone remodeling and bone marrow adipocyte differentiation. Ten-week-old female Sprague-Dawley rats underwent sham operation (Sham) or were ovariectomized (OVX) and were divided into four groups: Sham, Sham+ARa, OVX, and OVX+ARa groups. They were given orally the b3-ARa, BRL 35135, or vehicle daily for 4 weeks and their tibial and lumbar spinal bone and fat histomorphometric parameters were measured. In tibial proximal metaphysis, the adipocyte number per bone marrow unit volume (N.A/MV), and the percent adipocyte volume (AV/MV) values of the OVX and OVX+ARa groups were significantly higher than the Sham and Sham+ARa groups (P = 0.004, P = 0.008 in OVX, respectively), but ARa administration had no effect on bone remodeling or adipocyte differentiation. N.A/MV and AV/MV correlated negatively with the bone volume (BV/TV, r = -0.67, P = 0.001; r = -0.62, P = 0.004, respectively), and they correlated with the bone resorption parameters, i.e., the eroded surface (ES/BS), osteoclast surface (Oc.S/BS), and osteoclast number (N.Oc/BS) in tibial proximal metaphysis. In tibial distal metaphysis, the adipocyte volume per cell (AV/N.A) values of the OVX and OVX+ARa groups were significantly higher than those of the Sham and Sham+ ARa group (P = 0.003 in OVX). In the lumbar spine, the AV/N.A values of the Sham+ARa and OVX+ARa groups were significantly lower than the Sham and OVX groups values (P < 0.0001 in ARa administration), but OVX did not affect adipocyte differentiation. Beta3-ARa administration affects the bone marrow adipocyte differentiation, which is site-specific difference, although mainly negative in the context of bone.

Adipocytes↗

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

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

Salivary glands and lesions: evaluation of apparent diffusion coefficients with split-echo diffusion-weighted MR imaging--initial results.

The authors investigated the feasibility of performing diffusion-weighted (DW) magnetic resonance (MR) imaging with split acquisition of fast spin-echo signals (hereafter, split echo) for the assessment of salivary glands and salivary lesions. Eighteen patients without salivary disease and 10 patients with Sjögren syndrome, chronic parotitis, or focal salivary masses underwent split-echo and echo-planar DW MR imaging. DW MR images and apparent diffusion coefficient maps of the salivary gland had higher quality with split-echo rather than with echo-planar DW MR imaging.

Adult↗