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Akio Tanaka

Publications and source records attributed to Akio Tanaka.

16 recordsLinked to original sources
PubMed2007

Highly sensitive detection of HPV-DNA in paraffin sections of human oral carcinomas.

BACKGROUND: Although human papillomavirus (HPV) infection has been shown to be a significant carcinogen in cervical squamous cell carcinoma (SCC), its significance in oral SCC remains unclear. METHODS: We developed highly sensitive detection methods for HPV to elucidate the prevalence and localization of HPV in paraffin sections from human oral SCC using modified in situ polymerase chain reaction (PCR) and in situ hybridization AT tailing (ISH-AT). Analyses revealed a high prevalence of several HPV types (HPV-16, -18, -22, -38 and -70) under optimal conditions. The ISH-AT method can be used as an alternative to in situ PCR. RESULTS: Various staining patterns were observed in the 20 cases examined, and HPV-positive cells were localized within the surface epithelium as well as in neoplastic cells. We demonstrated that HPV-DNA could be detected in paraffin sections using either the method of in situ PCR or ISH, providing an appropriate primer and probe are used. CONCLUSION: These results suggest that HPV infection could be one of several risk factors being involved in oral SCC.

AT Rich Sequence↗
PubMed2006

Clinical significance of T1-weighted MR images following transient cerebral ischemia.

To try to determine the cause of hyperintensity of T1-weighted MR images that occurred on and after day 7 following transient cerebral ischemia, dynamic changes in T1-weighted images and histology of rats subjected to 20 min of 4-vessel occlusion were observed. T1-weighted images showed no remarkable alteration on days 1 and 3, although high signal intensity in the striatal region, in which the T1 value was significantly lower than the values on days 1 and 3, was observed on day 7. High signal intensity in T1-weighted images indicates low T1 values. Histological observation revealed accumulation of microglia in the striatal region on day 7 by lectin staining. There was a tight correlation between T1 values and number of lectin-positive cells. Microglia had stout processes and hypertrophic cell bodies on day 7, resembling lipid-laden phagocytes. Sudan black B staining showed the presence of many fatty droplets in the striatal region on day 7. Furthermore, double staining with lectin and Sudan black B revealed the presence of fatty droplets in bodies of lectin-positive cells on day 7. These results suggest that hyperintensity of T1-weighted images on day 7 following transient ischemia and reperfusion indicates accumulation and phagocytic activation of microglia. T1-weighted images seem to represent the progression of non-reversible tissue injury after transient ischemia and reperfusion.

Animals↗
PubMed2006

Imaging diagnosis and fundamental knowledge of common brain tumors in adults.

The most common primary brain tumors in Japanese adults are meningiomas, gliomas, pituitary adenomas, and schwannomas, which together account for 84.0% of all primary brain tumors. The typical imaging findings of these tumors are well known by radiologists; therefore, the clinical and pathological issues, including terminology, genetics, and relation to hormones are discussed in this article. Other diseases important for the differential diagnoses are also mentioned. The molecular genetic analysis of brain tumors has recently become important. For instance, genetic analysis is important for differentiating oligodendroglial tumors from astrocytic tumors, and the gene mutation predicts response to chemotherapy for anaplastic oligodendrogliomas. Background factors such as hormones, history of cranial irradiation, and medications influence oncogenesis, tumor growth, and tumor appearances as seen by imaging modalities. A differential diagnosis with knowledge of the above may have some advantages over diagnoses based on imaging findings alone. Nonneoplastic diseases such as abscesses and demyelinating diseases may mimic gliomas. Pituitary adenomas may be confused with nonneoplastic conditions such as physiological hypertrophy and Rathke's cleft cyst. Such misdiagnoses would result in a treatment protocol very different from what would be suitable. Such conditions should be carefully distinguished from neoplasms.

Adult↗
PubMed2006

Calcification at the interface between titanium implants and bone: observation with confocal laser scanning microscopy.

It has not been previously possible to observe bone formation in undecalcified sections with titanium implants at high magnification because of the difficulty in sectioning bone together with implants. A method for examining the bone-implant interface in undecalcified sections is described in which implants are left in situ and confocal laser scanning microscopy (CLSM) is used to examine both the implant surface and adjacent bone. Pulsing of animals at different times with the fluorescent dyes calcein and alizarin red permitted assessment of temporal patterns of bone formation by CLSM. Reflectivity of the polished implant surface permitted accurate assessment of the position of the implant relative to labeled bone. The analysis showed that bone first formed as thin processes towards and across the implant surface, followed by further bone formation behind these processes. The interface between calcified bone tissue and the implant surface was characterized by a 10-microm space. The CLSM technique enabled detailed observations of new bone formation at the titanium implant interface.

Animals↗
PubMed2005

Bone repair analysis in a novel biodegradable hydroxyapatite/collagen composite implanted in bone.

The purpose of this study was to evaluate a biodegradable hydroxyapatite/collagen composite and to examine the use of the calcium ion contained for bone formation and growth. Surgical holes were prepared in the femora and tibiae of beagle dogs, and were filled with the hydroxyapatite/collagen composite labeled with alizarin red. After 4 weeks, calcein was administered to the experimental dogs. After 1 additional week, the femora and tibiae were removed surgically and fixed in formalin. Light microscopy and confocal laser scanning microscopy were used to examine the surgical holes with their implanted materials and the surrounding bone. There were only a few inflammatory cells adjacent to the hydroxyapatite/collagen composite. The newly formed bone in the cortical bone was stained with calcein, which binds to serum calcium, and new bone near the hydroxyapatite/collagen composite in the holes was stained positive for alizarin red, which binds to the calcium in the hydroxyapatite/collagen composite. In addition, osteoblasts near the hydroxyapatite/collagen composite as well as newly formed bone adjacent to the osteoblasts showed alizarin red staining, but the new bone at a distance from the hydroxyapatite/collagen implant reacted only to calcein staining. These results, using the tissue labeling method with calcein and alizarin red, suggested that the calcium bound to the alizarin red released from the hydroxyapatite/collagen composite materials might have been translocated to sites of new bone formation. The present experiment showed that the novel hydroxyapatite/collagen composite is a useful implant material for bone augmentation and that the calcium in the newly formed bone might have been released from the implant.

Absorbable Implants↗
PubMed2005

Immunohistochemical co-localization of lymphatics and blood vessels in oral squamous cell carcinomas.

BACKGROUND: Differentiating lymphatic vessels from blood vessels is difficult, partly due to the lack of a specific method for identifying lymphatics. A new lymphatic vessel-reactive antibody, D2-40 has recently become commercially available. We examined the selectivity of D2-40 for lymphatics in oral neoplastic lesions for discrimination from blood vessels. METHODS: Formalin-fixed, paraffin-embedded sections of oral lymphangiomas (n = 3), oral hemangiomas (n = 7), and oral squamous cell carcinomas (OSCC, n = 46) were double immunostained with D2-40 and anti-CD34 monoclonal antibodies (MoAb) using ENVISION-polymer technique with 5-bromo-4-chloro-3-indoxyl-phosphate (BCIP)/nitroblue tetrazolium chloride (NBT) and 3,3'-diaminobenzidine (DAB) as color reagents, respectively. RESULTS: In the oral lymphangiomas and hemangiomas D2-40 was detected in all lymphatics, while all blood vessels were positive for CD34. In OSCC, number of vessels for lymphatics (P < 0.01) and for blood vessels in the perineoplastic areas were significantly greater than those in intratumoral areas. CONCLUSIONS: These results indicate that lymphatic proliferation might be much more extensive in the peritumoral area than intratumoral.

3,3'-Diaminobenzidine↗
PubMed2005

Marker of cemento-periodontal ligament junction associated with periodontal regeneration.

OBJECTIVE: The purpose of this study was to identify factors promoting formation of the cemento-periodontal ligament junction. BACKGROUND: Regeneration of the cemento-periodontal ligament junction is an important factor in recovery of the connective tissue attachment to the cementum and it is important to identify all specific substances that promote its formation. To clarify the substances involved in cemento-periodontal ligament junction formation, we produced a monoclonal antibody (mAb) to human cemento-periodontal ligament junction (designated as the anti-TAP mAb) and examined its immunostaining properties and reactive antigen. METHODS: Hybridomas producing monoclonal antibody against human cemento-periodontal ligament junction antigens were established by fusing P3U1 mouse myeloma cells with spleen cells from BALB/c mice immunized with homogenized human cemento-periodontal ligament junction. The mAb, the anti-TAP mAb for cemento-periodontal ligament junction, was then isolated. The immunoglobulin class and light chain of the mAb were examined using an isotyping kit. Before immunostaining, antigen determination using an enzymatic method or heating was conducted. Human teeth, hard tissue-forming lesions, and animal tissues were immunostained by the anti-TAP mAb. RESULTS: The anti-TAP mAb was positive in human cemento-periodontal ligament junction and predentin but negative in all other human and animal tissues examined. In the cemento-osseous lesions, the anti-TAP mAb was positive in the peripheral area of the cementum and cementum-like hard tissues and not in the bone and bone-like tissues. The anti-TAP mAb showed IgM (kappa) and recognized phosphoprotein. CONCLUSION: The anti-TAP mAb is potentially useful for developing new agents promoting cementogenesis and periodontal regeneration.

Animals↗
PubMed2005

Analysis of eosinophilic round bodies formed after injection of enamel matrix derivative into the backs of rats.

BACKGROUND: Enamel matrix derivative (EMD) is used in dental clinics for the regeneration of alveolar bone. Its effects have not yet been clarified, although it induces eosinophilic round bodies (ERBs) and cartilage formation at the injection site. The objective of this experiment was to examine the histopathologic and biochemical properties of ERBs formed after EMD injection. METHODS: The backs of Sprague-Dawley rats injected with various concentrations of EMD were examined histopathologically. For biochemical examinations, ERBs were microdissected out from the sections. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), matrix-assisted laser-desorption ionization time-of-flight (MALDI-TOF) mass spectrometry (MS), and database analysis of ERBs were carried out. RESULTS: The histopathological findings were consistent with a foreign body reaction. Numerous ERBs were observed 7 days after injection of 30.0 mg/ml EMD. Histopathologically, ERBs did not contain polysaccharide, amyloid, or hemosiderin. The cells surrounding ERBs were not macrophages or vascular endothelial cells. SDS-PAGE of the microdissected ERBs revealed an intense band at around the 40-kDa region. MALDI-TOF MS showed that the spectrum for ERBs has only a single strong ion intensity. Analysis of the amino acid sequence revealed that the ERBs were composed of various molecular fragments, which all contained an identical seven amino acid sequence. In addition, these peptides are a component of amelogenin. CONCLUSIONS: A high concentration of EMD induces ERBs that consist of a 40-kDa protein which includes a constituent part of amelogenin. The ERBs (or remaining EMD) might promote mesenchymal cell differentiation into hard tissue-forming cells around the EMD injection site.

Amelogenin↗
PubMed2004

Pelodera strongyloides infestation presenting as pruritic dermatitis.

Pelodera strongyloides is a free-living soil nematode of the order Rhabditida. We report an 18-year-old man with P strongyloides skin infestation. In this case, pruritic follicular papulopustules developed on the buttocks, then the right flank. Skin scrapings revealed many live rhabditiform larvae that were cultured adult worms and hatched ova, identified as P strongyloides . The eruption was treated effectively with topical 1% gamma-hexachlorocyclohexane ointment.

Adolescent↗
PubMed2004

Expression of RCAS1 and its function in human squamous cell carcinoma of the oral cavity.

Receptor-binding cancer antigen expressed on SiSo cells (RCAS1) is a recently discovered human tumor-associated antigen expressed in a wide variety of cancer tissues. It has been suggested that tumor cells evade from immune surveillance by expression of RCAS1. We investigated whether RCAS1 is expressed in human oral squamous cell carcinomas (HOSCCs) or HOSCC (HSC-2, -3, -4, Ca9-22 and KB) cells and whether tumor cells expressing RCAS1, induce apoptosis in its receptor-positive cells, peripheral blood lymphocytes (PBLs). RCAS1 transcripts and proteins were detected in five HOSCC cell types. Immunohistochemical examinations revealed that RCAS1 was slightly to moderately positive in 32 of 40 cases (80%) of HOSCCs. Furthermore, the frequency of RCAS1 expression in HOSCC increased with advancing tumor stage according to the pTNM system. Confocal laser microscopy and DNA fragmentation assay showed that PBLs, which were stimulated with IL-2, underwent apoptosis by co-culturing with KB cells. It was also confirmed by Western dot blotting that soluble RCAS1 is secreted into culture supernatants of KB cells. The apoptotic tumor-infiltrating lymphocytes (TILs) were detected around RCAS1-positive tumor cells in HOSCCs by TUNEL method. These results suggest that RCAS1 expression might be associated with progression of oral tumors and offer a possible mechanism for oral cancer immune escape.

Adult↗
PubMed2003

Development of a tissue-equivalent MRI phantom using carrageenan gel.

A new tissue-equivalent MRI phantom based on carrageenan gel was developed. Carrageenan gel is an ideal solidifying agent for making large, strong phantoms in a wide variety of shapes. GdCl(3) was added as a T(1) modifier and agarose as a T(2) modifier. The relaxation times of a very large number of samples were estimated using 1.5-T clinical MRI equipment. The developed phantom was found to have a T(1) value of 202-1904 ms and a T(2) value of 38-423 ms when the GdCl(3) concentration was varied from 0-140 mumol/kg and the agarose concentration was varied from 0-1.6% in a carrageenan concentration that was fixed at 3%. The range of measured relaxation times covered those of all types of human tissue. Empirical formulas linking the relaxation time with the concentration of the modifier were established to enable the accurate and easy calculation of the modifier concentration needed to achieve the required relaxation times. This enables the creation of a phantom having an arbitrary combination of T(1) and T(2) values and which is capable of retaining its shape.

Carrageenan↗
PubMed2002

Childhood-onset epilepsy associated with polymicrogyria.

To study the electroclinical characteristics of patients with childhood-onset epilepsy who showed polymicrogyria (PMG) on MRI, we classified 15 patients according to the location of PMG on MRI. The composition of the subjects was as follows: four patients with PMG in both hemispheres; three with localized PMG in one hemisphere associated with other lesions such as porencephaly; and eight with only localized PMG in one hemisphere. We investigated the electroclinical characteristics of the epileptic syndromes associated with these different types of PMG. Four patients suffered from infantile spasms during their clinical course. Five patients suffered from epilepsy with electrical status epilepticus during slow sleep (ESES) and ESES-related epilepsy. The other six patients had only localization-related epilepsy throughout their clinical course. Patients with PMG in both hemispheres, and localized PMG in one hemisphere associated with other lesions tended to have early-onset intractable seizures, especially infantile spasms. On the other hand, patients with only localized PMG in one hemisphere had ESES and ESES-related epilepsy or localization-related epilepsy, and their seizure prognosis was relatively favorable. These findings are useful in predicting the outcome of patients with PMG.

Adolescent↗
PubMed2002

[A case of large carcinoma of the tongue and mouth floor, in which chemotherapy using a combination of nedaplatin and 5-FU was effective].

We encountered a case of extensive squamous cell carcinoma ranging from the tongue to the mouth floor, in which chemotherapy using a combination of nedaplatin and 5-FU was effective. The patient was a 46-year-old male, who noticed a small mass in the mouth floor in September 2000, and visited the department of oral and maxillofacial surgery at a hospital on October 12, 2000. A 27 x 15 mm tumor with erosion was noted on the mouth floor, which was diagnosed as squamous cell carcinoma by biopsy, and the patient was referred to our department for treatment on November 16, 2000. Intra-oral findings included a healthy-colored induration with a bulge in the area ranging from the apex of the tongue posteriorly for 30 mm, and from the right lateral edge of the tongue to the left side exceeding the median area of the tongue by approximately 7 mm. MRI detected a tumor of approximately 2 cm in diameter in the area ranging from the median area of the tongue to the right ventral side of the tongue, which protruded on the mouth floor side. Two courses of combination chemotherapy using nedaplatin and 5-FU were performed. Nedaplatin (90 mg/m2, total 143 mg) and 5-FU (700 mg/m2, total 1,113 mg) were administered in a first course during December 15-19, 2000, and in the same amounts in a second course during January 23-27, 2001. Adverse effects of gastralgia and stomatitis occurred, but they gradually disappeared with time. The tumor with erosion in the tongue and mouth floor and induration disappeared 2 weeks after administration. Tongue was recovered, so that tongue movement was almost normal. Postoperative MR showed no abnormal signals in T2-weighed images, suggesting that the tumor in the right mouth floor had almost disappeared. External irradiation (40 Gy/20 times/28 days, 2 Gy/day, opposing bilateral portal irradiation) between March 13 and April 9, 2001, and micro-selection high dose fractionated interstitial irradiation (42 Gy/7 times/6 days, 6 Gy/1 time) April 18-23, 2001 were performed as booster therapy. Outpatient observation has shown a good clinical course without recurrence.

Antineoplastic Combined Chemotherapy Protocols↗
PubMedDate not supplied

Presence of protein complex is prerequisite for aragonite crystallization in the nacreous layer.

We have isolated a protein complex from the nacreous layer of pearl beads and oyster shells. This complex was mainly composed of pearlin and pearl keratin. Addition of a minute amount of the complex to a calcium-carbonate-saturated solution containing Mg2+ induced aragonite crystallization. The complex was dissociated to individual components in the presence of EDTA and urea. Conversely, the complex was reconstituted from a mixture of components upon incubation with Ca2+ and urea. The mixture of the components was unable to induce aragonite crystallization, but the reconstituted complex recovered this capacity. Thus it is concluded that the complex is the indivisible functional unit required for aragonite crystallization.

Animals↗
PubMedDate not supplied

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL/APO2L) and its receptors expression in human squamous cell carcinoma of the oral cavity.

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL/APO2L) is a novel member of the tumor necrosis factor cytokine family and a potent inducer of apoptosis in tumor cells. TRAIL is expressed in most normal human cells and tissues, including peripheral blood leukocytes, spleen, lung and prostate. However, TRAIL expression in human neoplasms is largely unknown. In this study, we investigated whether TRAIL and its receptors are expressed in human oral squamous cell carcinomas (HOSCCs) or HOSCC cell lines (HSC-2, HSC-3, HSC-4, Ca9-22 and KB) and whether these cells are sensitive to TRAIL-induced apoptosis. TRAIL and its receptor transcripts and proteins were detected in all HOSCC cell lines. A cell viability (MTT) assay performed after exposure to recombinant human (rh) TRAIL for 16 h showed that KB cells were the most sensitive. Immunohistochemical examinations for TRAIL expression were also carried out in a total of 50 HOSCC cases with various types of differentiation. In 17 of 27 WHO Grade 1 SCCs, the tumor invasive areas with keratinization showed diffuse and moderate TRAIL expression. In 6 of 20 WHO Grade 2 SCCs, TRAIL expression was slightly to moderately detected. In 1 of 3 WHO Grade 3 SCCs, a slight TRAIL expression was observed. Thus, there is considerable heterogeneity of TRAIL expression and susceptibility to TRAIL-induced apoptosis among human oral tumors.

Apoptosis↗