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Biomedical subjects

Hirotsugu Yamamoto

Publications and source records attributed to Hirotsugu Yamamoto.

At least 19 recordsLinked to original sources
PubMed2006

Clinical and diagnostic features of mucous membrane pemphigoid.

The aim of this study was to characterize the clinical and diagnostic features of mucous membrane pemphigoid (MMP). Five MMP patients were evaluated, and biopsies were obtained for routine histopathology and direct immunofluorescence. Circulating autoantibodies were verified by indirect immunofluorescence. Circulating immunoglobulin G autoantibody specific for 180 kDa bullous pemphigoid antigen (BP180) was evaluated by enzyme-linked immunosorbent assay (ELISA). All 5 patients complained of erythematous gingiva. Two patients had extraoral lesions involving the nasal mucosa, eyes, and skin. Histopathological confirmation was established for 4 of the patients, while direct immunofluorescence findings were positive in all 5. Although circulating autoantibodies were not identified by indirect immunofluorescence, the BP180 ELISA was positive in 3 cases. Both histopathological and direct immunofluorescence examinations are essential to establish a definitive diagnosis. Identification of circulating BP180 specific autoantibody shows promise.

Aged↗
PubMed2005

Image processing based on seeded spontaneous optical pattern formation by optoelectronic feedback.

Spontaneous optical pattern formation from an initial seed optical pattern in an optoelectronic system with optical diffractive feedback is investigated experimentally. We demonstrate that the temporal evolution of the spontaneously formed patterns exhibits a contrast enhancement effect, a spatial filtering effect, and filling of vacant space while the surrounding structures are maintained. These effects allow us to perform image processing of natural fringe patterns, i.e., in our experiments, fingerprint patterns. We also demonstrate image processing with defect invariance for fingerprint patterns.

Journal Article↗
PubMed2005

Early detection and successful management of oral pemphigus vulgaris: a case report.

BACKGROUND: Pemphigus vulgaris (PV) is an autoimmune disease characterized by acantholysis in the epithelium. PV is often difficult to diagnose in the early stages, since the oral lesions are relatively nonspecific. We report on a case with a favorable outcome due to early diagnosis and effective treatment of oral lesions. METHODS: A 53-year-old Japanese woman presented with a month-long history of painful gingiva. PV was diagnosed using clinical, histopathological, and direct immunofluorescence criteria 1 month after the first visit. Evaluation of the circulating autoantibody titers to desmoglein (Dsg)1 and Dsg3 was conducted by enzyme-linked immunosorbent assay (ELISA). Occlusive steroid therapy (OST) using a topical corticosteroid (0.1% triamcinolone acetonide) was provided for 8 weeks. After OST was completed, a buccal frenectomy was performed to eliminate localized toothbrushing trauma. RESULTS: There were no adverse effects on wound healing after the procedure. No oral PV lesions were detectable at the 9-month reevaluation, and the patient remains in complete remission. The Dsg1 ELISA was negative while the Dsg3 ELISA was indeterminate at the first visit. The Dsg1 ELISA was also negative at reevaluation, but Dsg3 ELISA reactivity had increased 9 months after completion of treatment. CONCLUSION: Large scale clinical trials will be required to validate the clinical benefits of the OST treatment regimen, and further research is necessary to determine the importance of ELISA antibody examination in long-term management of oral PV.

Adrenal Cortex Hormones↗
PubMed2005

Mucous and ciliated cell metaplasia in epithelial linings of odontogenic inflammatory and developmental cysts.

The incidence of mucous and ciliated cells in epithelial linings was examined among odontogenic inflammatory cysts (radicular cysts) and developmental cysts (dentigerous and primordial cysts). Mucous cells were found in 20.8% of all cysts examined, while ciliated cells were found in 11.4%; however, ciliated cells were always accompanied by mucous cells. The incidence of mucous cells in radicular cysts and dentigerous cysts and that of ciliated cells in radicular cysts was higher in the maxilla than in the mandible, while the incidence of mucous cells in primordial cysts and that of ciliated cells in dentigerous cysts and primordial cysts was higher in the mandible than in the maxilla. The present results regarding mucous cells and ciliated cells in the epithelial linings of intraosseous odontogenic cysts indicate a metaplasic origin, but the cause and biological significance of this phenomenon is not known. Mucous cells were present in the surface layer of epithelial linings, and intraepithelial gland-like structures lined with mucous cells were observed in the hyperplastic regions of epithelial linings of several radicular and dentigerous cysts. Such gland-like structures lined by mucous cells in the thickened epithelial lining, which have not been demonstrated previously, resembled the glandular structures of "glandular odontogenic cysts".

Cilia↗
PubMed2004

Hiding an image with a light-scattering medium and use of a contrast-discrimination method for readout.

Hiding image data with a material such as a light-scattering medium is useful as an initial stage of data protection, because the hidden image can be detected only by observation with a specific technique. A light-scattering medium is used to hide the image data, and a low-temporal-coherence interferometer performs the readout processing. A new readout method for detecting pixel values of the image is proposed to overcome spatial variation of the light intensity and distortion of the interference fringes. The introduction of spatial coding further improves the performance by overcoming spatial variations of the light-scattering medium and variations in the reflectance of given pixels.

Computer Security↗
PubMed2004

Congenital absence of the permanent canines: a clinico-statistical study.

We report here a clinico-statistical study of congenital absence of the permanent canines (CAPC). Sixty-five cases (22 men and 43 women) of CAPC were found in the files of 35,927 outpatients, an incidence of 0.18%. Thirty-seven cases had single absence of the canine and 28 cases had multiple absences. There were 42 cases in the maxilla, 17 in the mandible, and 6 in both the maxilla and the mandible. In the single absence cases, there was a tendency of occurrence at the left side in the maxilla, and the right side in the mandible. There were 39 CAPC cases without absence of other permanent teeth. Several complicated dental anomalies were seen such as persistence of deciduous teeth, congenital absence of other permanent teeth, microdontia, malposition, and complete or incomplete impaction (excluding the third molars). The complication rate of other permanent tooth absences was higher in the cases with CACP in the maxilla than in the mandible.

Adolescent↗
PubMed2003

Spatially localized states with size-dependent optical bistability.

Experimental results of a new type of localized state generated in an optical system consisting of a liquid-crystal spatial light modulator with optical feedback are demonstrated. The localized state is triggered at a position that depends on the size of a control beam because its formation depends on the fraction of high-spatial-frequency components in the feedback light that passes through a low-cut spatial-frequency filter. This novel size-dependent switching property is useful for erasing individual target localized states.

Journal Article↗
PubMed2003

Securing information display by use of visual cryptography.

We propose a secure display technique based on visual cryptography. The proposed technique ensures the security of visual information. The display employs a decoding mask based on visual cryptography. Without the decoding mask, the displayed information cannot be viewed. The viewing zone is limited by the decoding mask so that only one person can view the information. We have developed a set of encryption codes to maintain the designed viewing zone and have demonstrated a display that provides a limited viewing zone.

Journal Article↗
PubMed2003

Histopathological and immunohistochemical study of malignant transformation of oral leukoplakia, with special reference to apoptosis-related gene products and proliferative activity.

OBJECTIVE: To examine the frequency of apoptosis in oral leukoplakia and its relationship with pathological parameters, including Ki-67 expression, and with the expression of p53, Bcl-2 and Bax proteins. MATERIAL AND MEHODS: Clinical, histopathological and immunohistochemical studies were carried out and the terminal deoxynucleotide transferase-mediated dUTP nick-end labeling method was used to verify the apoptosis and its mechanism of genetic control of the development, progression and promotion of lesions. The material consisted of five normal mucosal epithelia. six leukoplakias without malignant transformation and seven leukoplakias with malignant transformation. Based on counts of 10 fields at a magnification of x 400, mitotic, apoptotic and Ki-67 indices were calculated, and p53, Bcl-2 and Bax expressions were recorded. RESULTS: The peak of the mitotic and Ki-67 indices and p53 expression shifted basally, possibly as a result of malignant transformation, whilst the peak of apoptosis and the expression of apoptotic-related proteins in oral leukoplakia showed no transformation. CONCLUSION: The frequent expression of Bcl-2 in oral leukoplakia with malignant transformation combined with the reduction in the number of apoptotic cells indicated that malignancy occurred as a result of the avoidance of apoptosis. In addition, high levels of Bax expression in oral leukoplakia without malignant transformation indicated that the Bcl family may play a role in the progression of the disease.

Aged↗
PubMed2003

Nasally administered cholera toxin A-subunit acts as a mucosal adjuvant.

It is well established that cholera toxin (CT) produced by Vibrio cholerae acts as a potent mucosal adjuvant; however, the native form of this molecule causes severe diarrhea. Furthermore, both native CT and its B-subunit derivative bind to monosialogangliosides (GM1) in membrane raft micro-domains on neural tissues and are thus unsuitable for use in humans. In this study, we evaluated the adjuvanticity of the CT A-subunit (CT-A) administered with ovalbumin (OVA) by the nasal route. We found that nasal administration of OVA plus CT-A elicited both mucosal and systemic antibody (Ab) responses. Immunization of mice with OVA plus CT-A resulted in the induction of OVA-specific IgA Abs in saliva and nasal secretions. Furthermore, significant OVA-specific serum immunoglobulin (Ig) G and IgA Ab responses were induced. Antibody-forming cell (AFC) analysis confirmed the Ab titer findings by revealing significant numbers of OVA-specific IgA AFCs in submandibular glands. In addition, splenic lymphocytes restimulated with OVA in vitro exhibited significant proliferative responses. Thus, CT-A might be a candidate for an effective adjuvant for inducing antigen (Ag)-specific Ab responses in human systemic and mucosal compartments, such as the oral cavity.

Adjuvants, Immunologic↗
PubMed2002

Enlargement of viewing area of stereoscopic full-color LED display by use of a parallax barrier.

In a stereoscopic full-color LED display by use of a parallax barrier, we discuss optimization of the viewing area, which depends on the width of the black regions between LEDs. Although conventional stereoscopic displays use a parallax barrier to permit the viewer to view stereoscopic images without any special glasses, their viewing area is restricted by crosstalk and the disappearing of pixels. Widening of the viewing area is examined by use of full-color panels with black regions having different widths. The optimum aperture ratio of the parallax barrier is obtained by analyzing the viewing area. An enlarged viewing area has been demonstrated by use of a 3-in-1 chip LED panel that has wider black regions than ordinary LED lamp cluster panels.

Journal Article↗
PubMed2002

Trabecular bone response to surface roughened and calcium phosphate (Ca-P) coated titanium implants.

The influence of calcium phosphate (Ca-P) coating and surface roughness on the trabecular bone response of titanium implants was investigated. Four types of titanium implants, i.e. blasted with titanium powder, sintered with titanium beads, titanium powder blasted and provided with an additional Ca-P coating, and titanium beads with Ca-P coating, were prepared. The Ca-P coating was deposited by ion beam dynamic mixing method. The Ca-P coating was rapid heat-treated with infrared radiation at 700 degrees C. The implants were inserted into the trabecular bone of the left and right femoral condyles of 16 rabbits. After implantation periods of 2, 3, 4 and 12 weeks, the bone-implant interface was evaluated histologically and histomorphometrically. Histological evaluation revealed new bone formation around different implant materials after already 3 weeks of implantation. After 12 weeks, mature trabecular bone surrounded all implants. At 3 and 4 weeks of implantation, no difference existed in bone contact to the various implant materials. On the other hand, after 12 weeks of implantation the highest percentage of bone contact was found around the Ca-P coated beads implants. Supported by the results, we concluded that the combination of surface geometry and Ca-P coating benefits the implant-bone response during the healing phase.

Animals↗
PubMed2002

Cellular schwannoma in the oral mucosa.

A case of cellular schwannoma of the oral mucosa in a 34-year-old Japanese man is described. Cellular schwannoma commonly affects soft tissues such as the retroperitoneum and posterior mediastinum, and also bone, but is extremely rare in the oral region. To our knowledge, this is only the second report of oral cellular schwannoma. Histologically, the tumor parenchyma consisted of hypercellular spindle cells with nuclear and cytoplasmic pleomorphism and nuclear palisading resembling Antoni A-type conventional schwannoma, without evidence of Verocay bodies. These features were indicative of cellular schwannoma. Immunohistochemically, the tumor cells were positive for S-100, S-100alpha, S-100beta and vimentin, suggesting that they were of peripheral nervous origin. Furthermore, it is speculated that the tumor was intermediate between a benign and a malignant state, based on the histological features and positivity for S-100alpha.

Adult↗
PubMed2002

Primary intraosseous carcinoma arising from an odontogenic cyst: a case report and review of the Japanese cases.

A rare case of primary intraosseous carcinoma (PIOC) arising from an odontogenic cyst in a 58-year-old man is reported. Clinical and radiological examinations revealed an odontogenic cyst of the maxilla. Histopathologically, the lesion was composed of a cyst with a parakeratotic epithelial lining and well-differentiated squamous cell carcinoma, showing continuity between them without a connection to the oral mucosa. Twenty-eight well-documented Japanese cases of Type-1 PIOC, including the present case, were reviewed. The mean age of the 28 patients was 56.1 years, and the male to female ratio was 1.8:1.0. Compared with currently reported Japanese reviews of Type-3, foreign Type-1 and Type-3, there were no significant differences in mean patient age and sexual predominance, and no racial difference. The pathogenesis of Type-1 PIOC is also discussed.

Carcinoma, Squamous Cell↗
PubMed2002

Imprint cytology of ameloblastoma.

To reveal the characteristic features of the imprint cytology of ameloblastomas, we compared these features with the histopathological features of the same specimens. Twenty-five cases, histopathologically diagnosed as ameloblastoma, were used. Three cell types were recognized: small squamous epithelial cells which were polyhedral or spindle-shaped with some projections; naked cells with poorly defined cytoplasm showing tubular and palisade patterns in some areas; and large squamous epithelial cells with extensive wrinkled cytoplasm. Naked cells and small squamous epithelial cells were thought to correspond to the histopathological classifications of cuboidal to columnar cells, and polyhedral or spindle cells respectively. Large squamous epithelial cells were thought to be acanthomatous cells showing squamous metaplasia. Imprint cytology had characteristic advantages compared to fine needle aspiration cytology, and clearly reflected the histopathology of the lesions. Knowledge of the characteristic features of the cells observed in imprint cytology is important when undertaking cytodiagnosis using fine needle aspiration.

Adolescent↗
PubMed2002

A histologic and histomorphometric evaluation of two types of retrieved human titanium implants.

This study analyzed the interfacial human bone response to retrieved implants that had been functionally loaded in the human environment. A solid-screw titanium plasma-sprayed (TPS) implant was removed 5 years after implantation because of a fracture at the joint between the implant and the crown. A sand-blasted acid-etched titanium implant (SLA) was used as an anchorage for orthodontic treatment. At the end of the treatment, the SLA implant was removed. Both types were functionally loaded without any symptoms expressed by the patients. Histology showed bone contact between the TPS or the SLA implant and surrounding bone, but the SLA implant revealed much more interfacial bone contact. The contact microradiograms showed that the bone surrounding the TPS and SLA implants was highly calcified. The measured percentage of bone-implant contact around the SLA implant was significantly higher (P <.05) than that around the TPS implant.

Acid Etching, Dental↗
PubMedDate not supplied

Potential application of high-resolution microfocus X-ray techniques for observation of bone structure and bone-implant interface.

PURPOSE: The aim of the present study was to evaluate the potential application of 2 types of microfocus x-ray units to study the bone structure around dental implants and at the bone-implant interface. MATERIALS AND METHODS: IMZ titanium implants were placed in the maxilla and mandible of a beagle dog. After implantation periods of 1, 2, and 3 months, the bone-implant interface was evaluated with microfocus x-ray computed tomography (CT) and microfocus x-ray fluoroscopy. RESULTS: Microfocus x-ray CT images of the bone-implant specimen at 3 months after implant placement revealed a clear distinction between the implant and the bone. The implant surface was partially covered with bone, and direct contact between the implant and bone could be clearly seen. Differences in degrees of calcification were identified by the differences in relative black and white intensity. Microfocus x-ray fluoroscopy also showed clear features of the bone and titanium implant The original drill hole and new bone formation could be recognized. These findings corresponded with traditional histologic observations by light microscopy. DISCUSSION AND CONCLUSION: Microfocus x-ray techniques are non-destructive and require a very short examination time. They are considered useful to observe details of the bone structure and bone-implant interface. Microfocus x-ray fluoroscope and microfocus x-ray CT techniques can provide a clear and distinguishable image of the bone-implant interface because of their high spatial resolution.

Alveolar Process↗