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Biomedical subjects

Y Yanagi

Publications and source records attributed to Y Yanagi.

At least 19 recordsLinked to original sources
PubMed2006

Triamcinolone acetonide suppresses early proangiogenic response in retinal pigment epithelial cells after photodynamic therapy in vitro.

OBJECTIVE: To investigate the expression of proangiogenic and antiangiogenic factors, vascular endothelial growth factor (VEGF) and pigment epithelium-derived factor (PEDF) in retinal pigment epithelial (RPE) cells after photodynamic therapy (PDT), especially focusing on their change in the presence of triamcinolone acetonide. METHODS: Firstly, the cellular uptake of verteporfin was quantified after confluent ARPE-19 (human retinal pigment epithelial) cells were exposed to 5 microg/ml verteporfin combined with or without 1 microg/ml triamcinolone acetonide for 1 h. Secondly, ARPE-19 cells exposed to various doses of verteporfin were irradiated with 120 mJ/cm(2) light. After incubation with or without 1 microg/ml triamcinolone acetonide for 2 days, cell viability and expressions of VEGF and PEDF were assessed. RESULTS: Cellular uptake of verteporfin was not significantly changed by the presence of 1 microg/ml triamcinolone acetonide. In addition, 0.01-0.1 microg/ml of verteporfin showed a dose-dependent toxicity on the ARPE-19 cells 2 days after the light exposure. The presence of verteporfin at a concentration of 0.01 microg/ml did not affect the cell viability but significantly increased VEGF (p<0.001) and reduced PEDF (p = 0.03) expression. Administration of triamcinolone acetonide significantly suppressed both this increase in VEGF (p<0.001) and decrease in PEDF (p = 0.001). CONCLUSIONS: VEGF was increased and PEDF reduced in cultured RPE cells shortly after PDT even at a sublethal dose. Triamcinolone acetonide suppressed this proangiogenic response.

Cell Line↗
PubMed2006

A2e mediated phototoxic effects of endoilluminators.

AIMS: To compare the theoretical retinal threshold time for endoilluminators and experimental phototoxic effect using A2e laden retinal pigment epithelial (RPE) cells. METHODS: The spectral irradiances of three types of 20 gauge and 25 gauge endoilluminators, currently commercially available from two manufacturers, were evaluated in conditions where the total beam spectral power was divided by the beam spot size at an estimated use distance of 5 mm from the retina. The retinal threshold time was calculated using the guidelines recommended by the International Commission on Non-Ionizing Radiation Protection. In vitro, A2e laden cells were evenly exposed to light for 30 minutes with a standard endoilluminator positioned 1 cm above the cells and the cell viability was assessed by WST-1 assay. RESULTS: The retinal threshold times were within 1 minute for all the endoilluminators tested. A significant decrease in the viability of A2e laden RPE cells was observed after they were exposed to light from two of the three 20 gauge endoilluminators. Cell viability was not affected by the exposure to 25 gauge endoilluminators under the same conditions. There was no correlation between the theoretical threshold times and experimental data. CONCLUSIONS: Light exposure during vitrectomy can induce photochemical damage to the retina. Although the A2e laden RPE model may not correctly mimic a clinical situation, this model may be useful to estimate the possible photochemical damage to RPE cells that could not be deduced by a theoretical retinal hazard model.

Cell Line↗
PubMed2006

A case of recurrent ameloblastoma developing in an autogenous iliac bone graft 20 years after the initial treatment.

A case of recurrent ameloblastoma developing in an autogenous iliac bone graft 20 years after radical resection of primary mandibular ameloblastoma is presented. This case showed extensive bony resorption extending throughout the auto-grafted bone. Seeding to the graft bone was suspected as a cause of the recurrence in the iliac bone graft because wide destruction of the graft bone was observed without any prior signs and symptoms of intraoral mucosa. Consequently, extensive resection of bone as well as adjacent soft tissue was performed. Persistent follow-up examination is essential for management of ameloblastoma.

Aged↗
PubMed2005

Retinal degeneration is delayed by tissue factor pathway inhibitor-2 in RCS rats and a sodium-iodate-induced model in rabbits.

PURPOSE: To investigate the in vivo effects of tissue factor pathway inhibitor 2 (TFPI-2), which stimulates proliferation of retinal pigment epithelial cells, but not the proliferation of fibroblast and vascular endothelial cells in vitro, on retinal degeneration using a sodium-iodate (SI)-induced model in rabbits and Royal Collage of Surgeons (RCS) rats. METHODS: 79 microg of recombinant TFPI-2 (rTFPI-2) or vehicle alone was injected intravitreously to 18 eyes of 12 pigmented rabbits a day after 20 mg/kg of SI was intravenously administered. Retinal function was assessed 4, 7, 14, and 21 days after the injection by analysing amplitudes of the c-wave of a bright flash electroretinogram. Additionally, 10 microg of rTFPI-2 or vehicle alone was injected intravitreously to 11 eyes of RCS rats at both 3 and 4 weeks old, then the retina was examined histologically at 5 weeks old. RESULTS: The rTFPI-2-treated eyes in rabbits showed a significantly less decrease in the relative amplitude of the c-wave than control eyes on days 4 and 7. The thickness of the outer nuclear layer was significantly thicker and the vacuole in the photoreceptor layer was less frequently observed in the rTFPI-2-treated RCS rats than the controls. CONCLUSIONS: Intravitreal injection of TFPI-2 rescues SI-induced retinal degeneration in rabbits and naturally occurring retinal degeneration in RCS rats at least partly. These results may suggest that this compound can be utilized in the treatment of retinal degeneration.

Animals↗
PubMed2005

Bone deformity showing a deep coronoid notch of the mandible in a patient with neurofibromatosis type 1.

We present a case of a 10-year-old girl with neurofibromatosis type 1 related skeletal dysplasia. In the present case, a unilocular radiolucency at the left coronoid notch visible on a panoramic radiograph was suspected to be a neurofibroma. However, only the presence of bone deformities was observed on CT. Fat-like tissue adjacent to the bone deformities inside the left mandibular ramus was revealed, and the presence of neurofibroma was unequivocally denied on the MR images. However, biopsy of the lesion suggested neurofibroma. The diagnostic imaging 18 months after the first visit did not revealed a tumourous mass. However, careful follow up is required even though we could not prove the presence the lesion on the basis of imaging.

Biopsy↗
PubMed2004

Fluorescein angiography-guided indocyanine green angiography for the detection of feeder vessels in subfoveal choroidal neovascularization.

AIMS: To compare the newly devised fluorescein angiography (FA) - guided indocyanine green angiography (ICGA) with conventional ICGA for detecting feeder vessels in subfoveal choroidal neovascularization (CNV). METHODS: The detection of feeder vessels was attempted in 86 AMD patients with subfoveal CNV: 44 (age 70.4+/-4.5 years) underwent conventional ICGA (control group) and 42 (age 70.9+/-4.0 years) underwent an FA-guided ICGA (FA-guided group) using a double-detector scanning laser ophthalmoscope (SLO). In the control group, indocyanine green (ICG) was injected simultaneously with fluorescein. The patients were instructed to gaze forward localizing the fovea at the centre. In the FA-guided group, fluorescein sodium was injected a few minutes prior to ICG, and the patients were instructed to fixate in the appropriate direction by referring to the ongoing FA on the monitoring screen. In both groups, a 20 degrees visual angle was used to capture good images of feeder vessels in ICGA and, in case ICGA missed the first images of the entire CNV filling, an additional injection of ICG was given in the late phase to record the choroidal filling again. The overall detection rate, single-injection detection rate, double-injection rate and examination time were analysed using Fisher's direct exact probability test or Mann-Whitney's U-test. RESULTS: There was no significant difference in the overall detection of feeder vessels between the two groups (50% in the control group and 52.3% in the FA-guided group; P=0.49 with Fisher's direct exact probability test). However, in the FA-guided group, the single injection detection rate was significantly higher (45.1 and 15.9%, respectively; P<0.001 with Fisher's direct exact probability test); significantly less double injections were required (7.1 and 50%, respectively; P=0.003 with Fisher's direct exact probability test); and significantly shorter examination times were needed (9.6+/-3.7 and 14.1+/-6.8 min, respectively; P=0.02 with Mann-Whitney's U-test). CONCLUSION: FA-guided ICGA is effective for detecting feeder vessels of subfoveal CNV, minimizing the amount of ICG injected and the examination time compared to conventional ICGA.

Aged↗
PubMed2004

Transpupillary thermotherapy for treatment of exudative age-related macular degeneration in Japanese patients.

PURPOSE: To report the therapeutic outcome of transpupillary thermotherapy (TTT) for subfoveal choroidal neovascularizarion (CNV) in brown retina using a diode-laser with the setting of lower energy level compared to the previous studies on light-pigmented Caucasian patients. METHODS: A total of 19 subfoveal CNVs in 18 patients were treated with TTT. The power of diode-laser was set 160 mW for 1.2 mm beam, 270 mW for 2.0 mm beam, and 400 mW for 3.0 mm beam, and the laser was delivered for 1 min through a slit-lamp mounted-delivery system. Patients were followed up for a mean of 8.8 months (4-12 months). Visual acuity and the fundus change as judged by funduscopic examination and simultaneous fluorescein and indocyanine green angiography were evaluated. Visual acuity was measured by a Japanese standard Landolt visual acuity chart and converted to logarithm of the minimal angle resolution (log MAR) visual acuity for statistical analysis. Improvement or decline in vision was defined as change of more than 0.2 in log MAR visual acuity. RESULTS: In eyes with minimally classic or occult only CNV, visual acuity improved in two eyes (18%) stabilized in seven eyes (64%) and worsened in two eyes (18%). In eyes with predominantly classic CNV, visual acuity improved in two eyes (25%), stabilized in four eyes (50%) and worsened in two eyes (25%). In all, 15 (84%) eyes of all studied subjects had improvement in exudation. Two (11%) and one (5%) eye(s) were noted to have a significant post-treatment haemorrhage and retinal pigment epithelial tear, respectively. CONCLUSION: In patients with brown retinal colour, the treatment outcome of TTT was comparable to that of light-pigmented Caucasian patients with approximately half the laser power energy. Further randomized control studies are warranted.

Aged↗
PubMed2004

Radiographic examination of dentigerous cysts in the transitional dentition.

OBJECTIVES: To examine radiographically the relationship between the deciduous tooth and dentigerous cyst of the permanent successor during the transitional dentition. METHODS: From a retrospective review of all patients who visited our institution from April 1988 to August 2001, 70 patients under 16 years of age who had histologically confirmed dentigerous cysts that had developed from the central incisor to the second premolar were identified. These 70 patients were investigated using panoramic and periapical radiographs. RESULTS: In most cases (54 cases; 77.1%) the cyst was in the premolar region. Of the 54 premolars with dentigerous cysts, the overlying deciduous tooth had already been lost in 7 cases. Of the 47 remaining premolars with associated deciduous tooth, 35 (74.5%) had bone resorption of the periapical or bifurcation region, or irregular resorption of the associated deciduous tooth. Of the remaining 12 deciduous teeth with no periapical lesions, 9 had been treated with root canal therapy. Thus, 44 of these 47 cases (93.6%) had the possibility of inflammation at the deciduous tooth associated with the dentigerous cyst. Evidence from one case in the present study suggesting the process by which cyst development occurs is also given. CONCLUSION: Inflammatory change at the apex of the deciduous tooth may bring on a dentigerous cyst of the permanent successor.

Adolescent↗
PubMed2004

Radiographic examination of mesiodens and their associated complications.

OBJECTIVES: To examine mesiodens with regard to their status, their influence on adjacent teeth and their alteration during the follow-up period. METHODS: From retrospective reviews of all patients who visited our institution from 1990-2001, we identified 200 patients (256 mesiodentes) who were shown to have mesiodentes on the basis of a periapical radiograph, a panoramic radiograph or an axial radiograph. RESULTS: The number of supernumerary teeth was one in 146 cases (73%), two in 52 cases (26%) and three in 2 cases (1%). Of 256 mesiodentes, the direction of the crown of the mesiodens was inverted in 172 (67%), in a normal direction in 69 (27%) and in a horizontal direction with regard to the tooth axis in 15 (6%). Of the 147 mesiodentes for which axial radiography was performed, 131 (89%) were located at a palatal site against the dental arch, 16 (11%) overlapped the dental arch and none were at a labial site. Of our 200 cases, a delay of eruption of the permanent central incisor was seen in 12 (6%), malposition or rotation of the central incisor in 5 (2.5%) and dentigerous cyst formation arising from mesiodens in 22 (11%). Marked movement of the mesiodens was seen in 10 cases during the follow-up period of 5-7 years. Some complication arising from mesiodens was seen in 19.5% of all cases in our research. CONCLUSION: Although mesiodentes are not caused by malocclusion, they may cause it. A long period of impaction of mesiodentes may bring about dentigerous cyst formation or movement of the mesiodentes.

Adolescent↗
PubMed2003

Comparison of radiographic and MRI features of a root-diverging odontogenic myxoma, with discussion of the differential diagnosis of lesions likely to move roots.

Lesions that can produce divergence of the roots of teeth in the mandible include odontogenic cysts (odontogenic keratocysts, lateral periodontal cysts and radicular cysts), ameloblastomas, odontogenic myxomas, central giant cell granulomas, adenomatoid odontogenic tumors and aneurismal bone cysts, and other tumors. Moreover most benign jaw lesions can do this occasionally. However, when lesions--which show interradicular tear-shaped radiolucencies--are small it is often difficult to interpret them radiographically, because they do not show characteristic radiographic features. We describe a comparison of radiographic and magnetic resonance (MR) features of a root-diverging odontogenic myxoma, with discussion of the differential diagnosis of lesions likely to move roots. In addition, we discuss radiographic and MR features of possible lesions, which show similar radiographic findings to odontogenic myxoma.

Adult↗
PubMed2002

The measles virus hemagglutinin downregulates the cellular receptor SLAM (CD150).

Signaling lymphocyte activation molecule (SLAM), a cellular receptor for measles virus, was downregulated from the surface of cells infected with either the Edmonston or wild-type KA strain of measles virus. Transfection of the expression plasmid encoding the Edmonston or KA hemagglutinin, but not the fusion protein, induced downregulation of SLAM in not only cells expressing the envelope protein on the surface, but those not expressing it. After cocultivation with cells expressing the hemagglutinin, SLAM-expressing cells also exhibited downregulation of SLAM. Thus, the measles virus hemagglutinin can induce downregulation of SLAM in cells either expressing or coming in contact with it.

Animals↗
PubMed2002

Signal intensity changes in T2-weighted MR image of the human trapezius muscle upon cold pressor stimulation.

OBJECTIVE: The ability to measure hemodynamics of skeletal muscle proper is one of the major goals for muscle pain researchers. The aim of the present study was to evaluate the ability of signal intensity (SI) in T2-weighted trapezius muscle magnetic resonance imaging (MRI) to detect intramuscular hemodynamic changes during cold pressor stimulation (CPS). MATERIALS AND METHODS: Fifteen healthy volunteers (mean age, 25.9+/-2.1 years) participated in this study. T2-weighted MRI was acquired using a 1.5 tesla MR unit with a body array coil. The slice level was set perpendicular to the muscle long axis at the mid-point of the horizontal portion of the right trapezius muscle. Cold pressor stimulation (4 degrees C) was applied to each subject's right foot and ankle for 2 min. The SI changes were recorded continuously for 7 min before, 2 min during, and 6 min after withdrawal of cold pressor stimulation. Six of these subjects also underwent a mock-CPS trial. RESULTS: The mean SI level in T2-weighted trapezius muscle MRI significantly increased during CPS (P<0.0001, one way repeated measure ANOVA) and returned to the baseline level after cold pressor withdrawal. No statistically significant signal changes were observed across the mock-CPS trial subjects. These findings are identical to the cold pressor-induced hemodynamic changes documented in the trapezius muscle by near-infrared spectroscopy evaluation. CONCLUSIONS: SI measurement in T2-weighted trapezius muscle MRI is sufficiently sensitive to detect intramuscular hemodynamic changes during CPS.

Adult↗
PubMed2002

A study of hypoxic cell radiosensitizer applied to Ehrlich ascite tumour: a comparison of FC43 emulsion and pentoxyfilline.

In this study, we examined the effects of various combinations of treatments involving radiation, injections of perfluorochemicals (FC-43 emulsion) and injections of pentoxifylline on the growth delay of Ehrlich ascite tumours. Ehrlich ascite tumour cells were transplanted into the legs of ddY-strain mice. Tumour-bearing mice were divided into seven groups: group 1, no treatment; group 2, irradiated only; group 3, injected with FC-43 emulsion and kept in a carbogen atmosphere; group 4, injected with pentoxifylline and nicotinamide; group 5, injected with FC-43 emulsion, kept in a carbogen atmosphere and irradiated; group 6, injected with pentoxifylline and nicotinamide and irradiated; and group 7, injected with FC-43 emulsion, pentoxifylline and nicotinamide, kept in a carbogen atmosphere and irradiated. When 20 Gy irradiation was applied, tumour growth delay was 11 days in group 2, 20 days in group 5, 22 days in group 6, and 24 days in group 7. For a growth delay of 20 days, the dose modifying factor was 1.95+/-0.04 (standard deviations) in group 5, 1.97+/-0.09 standard deviations in group 6, and 2.01+/-0.07 standard deviations in group 7. It was concluded that FC-43 emulsion and pentoxifylline did not have an interactive effect.

Animals↗
PubMed2001

Correlation of the near-infrared spectroscopy signals with signal intensity in T(2)-weighted magnetic resonance imaging of the human masseter muscle.

The purpose of this study was to compare and contrast blood volume changes transcutaneously measured using near-infrared (NIR) spectroscopy against water signal intensity changes taken from a transverse T(2)-weighted MR image of the masseter muscle in healthy human subjects before, during and after contraction. Eight healthy non-smoking males with no history of chronic muscle pain or vascular headaches participated (mean age: 23.9+/-0.6 years). The MRI data were gathered using a turbo spin echo sequence (TR: 2300 ms; TE: 90 ms; FOV: 188x300 mm; scanning time: 30 s; slice thickness: 10 mm) and the slice level was set at the mid-point between the origin and insertion of the masseter. Intramuscular haemoglobin (Hb) levels and water content of the right masseter muscle were continuously monitored for 2 min before, 30 s during and 15 min after a maximum voluntary clenching (MVC) task. Both the near-infrared and MRI data were baseline-corrected and normalized and mean levels were established and plotted. Plots of the data showed that both near-infrared-based total Hb and T(2)-weighted MRI-based signal-intensity levels clearly decreased during contraction and a clear post-contraction rebound response was evident after the contraction. The near-infrared data were found to be highly correlated with MRI-based signal-intensity data (Pearson's r=0.909, P<0.0001). In conclusion, these data provide powerful evidence that near-infrared data (total Hb), transcutaneously taken from the masseter muscle in humans, will reflect the intramuscular water signal intensity changes seen using a T(2)-weighted MRI imaging method.

Adult↗
PubMed2001

CT and MR imaging of localized amyloidosis.

The localized form of amyloidosis affecting the head and neck region is rare. The characteristic features of localized amyloidosis appeared as multiple nodules on the tongue, lip, and cheek on computed tomography (CT) and magnetic resonance imaging (MRI). Contrast-enhanced CT scans represented this lesion as a marked nodular enhancement. MR features of this lesion appeared slightly low on T1-weighted images and slightly high on T2-weighted images compared with T1-T2 images of residual normal tongue. Time contrast intensity curves obtained from dynamic MRI rapidly increased to reach a plateau and gradually decreased during the late and delayed phases. MR findings suggest that such lesions might be comprised of fibrous tissue with abundant vessels. This report suggests that dynamic MRI might be helpful for diagnosing localized amyloidosis.

Aged↗