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Search Results: 1 - 10 of 941 matches for " Tsuyoshi Takato "
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A Case of Pleomorphic Adenoma of the Parotid Gland with Multiple Local Recurrences through Facial to Cervical Regions  [PDF]
Masanobu Abe, Yoshiyuki Mori, Yuki Kanno, Kazuto Hoshi, Hideto Saijo, Takahiro Abe, Kazumi Ohkubo, Tsuyoshi Takato
Open Journal of Stomatology (OJST) , 2014, DOI: 10.4236/ojst.2014.49059
Abstract: Pleomorphic adenoma is the most common benign parotid gland tumor. Although its local recurrence rate is known to be high, the recurrence extending to the cervical region is rare. Here we report a case of a young female (25 years old) with pleomorphic adenoma of the parotid gland which showed multiple recurrences through facial to cervical regions over a span of eight years. We also discuss how this benign tumor with a high recurrence rate has been treated in other cases, and how it should be treated.
Evaluation of in vivo migration of chondrocytes from tissue-engineered cartilage that was subcutaneously transplanted in mouse model  [PDF]
Mariko Matsuyama, Yuko Fujihara, Ryoko Inaki, Satoru Nishizawa, Satoru Nagata, Tsuyoshi Takato, Kazuto Hoshi
Open Journal of Regenerative Medicine (OJRM) , 2013, DOI: 10.4236/ojrm.2013.24013
Abstract:

For regenerative medicine, clarification of in vivo migration of transplanted cells is an important task to secure the safety of transplanted tissue. We had prepared tissue-engineered cartilage consisting of cultured chondrocytes with collagen hydrogel and a biodegradable porous polymer, and we clinically applied it for treatment of craniofacial anomaly. To verify the safety of this tissue-engineered cartilage, we had syngenically transplanted the tissue-engineered cartilage using chondrocytes harvested from EGFP-transgenic mice into subcutaneous pocket of wild type mice, and investigated localizations of transplanted chondrocytes in various organs including cerebrum, lung, liver, spleen, kidney, auricle, gastrocnemius, and femur. After 8 to 24 weeks of the transplantation, accumulation of cartilaginous matrices was observed in tissue-engineered cartilage, while EGFP-positive transplanted chondrocytes were localized in this area. Otherwise, no EGFP was immunohistochemically detected in each organ, suggesting that subcutaneously-transplanted chondrocytes do not migrate to other organs through the circulation. In cartilage tissue engineering using cultured chondrocytes, risk for migration and circulation of transplanted cells seemed negligible, and that ectopic growth of the cells was unlikely to occur, showing that this is safe technique with regard to the in vivo migration of transplanted cells.

Usefulness of Agarose Mold as a Storage Container for Three-Dimensional Tissue-Engineered Cartilage  [PDF]
Yoshiyuki Mori, Sanshiro Kanazawa, Makoto Watanabe, Hideyuki Suenaga, Kazumi Okubo, Satoru Nagata, Yuko Fujihara, Tsuyoshi Takato, Kazuto Hoshi
Materials Sciences and Applications (MSA) , 2013, DOI: 10.4236/msa.2013.48A010
Abstract:

The efficiency of substance exchange may be decreased when the thickness and volume of such a tissue-engineered cartilage that is composed of cultured cells and porous scaffold increase. Moreover, during the transport of this construct with complicated shapes, excessive and focal mechanical loading may cause deformation. The establishment of incubation and transport methods is necessary for the three-dimensional tissue-engineered cartilage. Therefore, we investigated the preparation of an agarose mold with a concavity similar to the shape of 3-dimensional tissue-engineered cartilage to prevent excessive and focal concentration of stress, while avoiding interference with substance exchange as much as possible. Firstly, we investigated the preparation at 1% - 4% agarose concentrations. Since the mechanical strength was insufficient at 1%, 2% was regarded as appropriate. Using 2% agarose, we prepared a mold with a 5 × 5 × 5 mm concavity to accommodate tissue-engineered cartilage (5 × 5 × 5 mm mixture of 1.5 × 107 cells and collagen gel), and stored the regenerative cartilage in it for 2 and 24 hours. On comparison with storage in a plastic mold with the same shape in which substance exchanged from side and bottom was impossible, although no significant differences were noted in the number or viability of cells after 2 hours, these were markedly reduced in the plastic mold after 24 hours. It was confirmed that favorable cell numbers and viability were maintained by immediately retaining the regenerative cartilage in the culture medium in the agarose mold and keeping the temperature at 37°C. Since this agarose mold also buffers against mechanical forces loaded on the three-dimensional regenerative tissue, it may be useful as a container for storage and transport of large-sized three-dimensional regenerative tissue

Hollow Fiber Module Applied for Effective Proliferation and Harvest of Cultured Chondrocytes  [PDF]
Yoshiyuki Mori, Makoto Watanabe, Sakae Nakagawa, Yukiyo Asawa, Satoru Nishizawa, Kazumi Okubo, Hideto Saijo, Satoru Nagata, Yuko Fujihara, Tsuyoshi Takato, Kazuto Hoshi
Materials Sciences and Applications (MSA) , 2013, DOI: 10.4236/msa.2013.48A008
Abstract:

Steady and useful culture for chondrocytes is essential for cartilage regenerative medicine. However, in conventional plate culture, the chondrocytes become dedifferentiated and lose their ability to make cartilage matrices. Three-dimensional culture mimicking the physiological environment in native chondrocytes is useful to maintain the chondrocyte properties during the proliferation culture. However, the three-dimensional culture is practically a hard task due to difficult harvest of the cells. Thus, we attempted to apply porous materials, hollow fibers for the three-dimensional culture, and developed their module to realize the effective harvest of the cells. Polyethersulfone-based hollow fibers, whose safety and cell affinity were confirmed by the experiment of the coculture with human chondrocytes, were collected to fabricate a module. The hollow fiber module was installed with screw ends, and enabled the easy removal of chondrocytes from the inner unit. Cultured human chondrocytes embedded within collagen hydrogel were put into the outer lumen of the hollow fiber module, while chondrocyte prolfieration medium was perfused through the inner lumen at 0 to 30 mL/min. After 2 weeks’ culture, the flow rate of 3 to 10 mL/min effectively supported the chondrocyte proliferation. Then, long-term culture using the hollow fiber module at flow rate of 5 mL/min was performed, revealing that the cell growth in this module at 3 weeks was approximately twice larger than that in static culture. The numbers of viable cells could be maintained by week 7. The hollow fiber module installed with screw ends can effectively culture and harvest the chondrocytes.

A Novel Strategy for Enrichment and Isolation of Osteoprogenitor Cells from Induced Pluripotent Stem Cells Based on Surface Marker Combination
Hiromi Ochiai-Shino, Hiroshi Kato, Takashi Sawada, Shoko Onodera, Akiko Saito, Tsuyoshi Takato, Takahiko Shibahara, Takashi Muramatsu, Toshifumi Azuma
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0099534
Abstract: In this study, we developed a new method to stimulate osteogenic differentiation in tissue-nonspecific alkaline phosphatase (TNAP)-positive cells liberated from human induced pluripotent stem cells (hiPSCs)-derived embryoid bodies (EBs) with 14 days long TGF-β/IGF-1/FGF-2 treatment. TNAP is a marker protein of osteolineage cells. We analyzed and isolated TNAP-positive and E-cadherin-negative nonepithelial cells by fluorescence-activated cell sorting. Treating the cells with a combination of transforming growth factor (TGF)-β, insulin-like growth factor (IGF)-1, and fibroblast growth factor (FGF)-2 for 14 days greatly enhanced TNAP expression and maximized expression frequency up to 77.3%. The isolated cells expressed high levels of osterix, which is an exclusive osteogenic marker. Culturing these TNAP-positive cells in osteoblast differentiation medium (OBM) led to the expression of runt-related transcription factor 2, type I collagen, bone sialoprotein, and osteocalcin (OCN). These cells responded to treatment with activated vitamin D3 by upregulating OCN. Furthermore, in OBM they were capable of generating many mineralized nodules with strong expression of receptor activator of NF-kappaB ligand and sclerostin (SOST). Real-time RT-PCR showed a significant increase in the expression of osteocyte marker genes, including SOST, neuropeptide Y, and reelin. Scanning electron microscopy showed dendritic morphology. Examination of semi-thin toluidine blue-stained sections showed many interconnected dendrites. Thus, TNAP-positive cells cultured in OBM may eventually become terminally differentiated osteocyte-like cells. In conclusion, treating hiPSCs-derived cells with a combination of TGF-β, IGF-1, and FGF-2 generated TNAP-positive cells at high frequency. These TNAP-positive cells had a high osteogenic potential and could terminally differentiate into osteocyte-like cells. The method described here may reveal new pathways of osteogenesis and provide a novel tool for regenerative medicine and drug development.
Minocycline for Schizophrenia: A critical review  [PDF]
Tsuyoshi Miyaoka
Open Journal of Psychiatry (OJPsych) , 2012, DOI: 10.4236/ojpsych.2012.224056
Abstract: Minocycline, an antibiotic of the tetracycline family, has been shown to display neurorestoractive or neuroprotective properties in various models of neurodegenerative diseases. In particular, it has been shown to delay motor alterations, inflammation and apoptosis in models of Huntington’s disease, amyotrophic lateral sclerosis and Parkinson’s disease. Despite controversies about its efficacy, the relative safety and tolerability of minocycline have led to the launching of various clinical trials. Previously, we reported the antipsychotic effects of minocycline in patients with schizophrenia. In a pilot investigation, we administered minocycline as an open-label adjunct to antipsychotic medication to patients with schizophrenia. The results of this trial suggested that minocycline might be a safe and effective adjunct to antipsychotic medications, and that augmentation with minocycline may prove to be a viable strategy for “boosting” antipsychotic efficacy and for treating schizophrenia. Recently, in randomized double-blind placebo-controlled clinical trials, the addition of minocycline to treatment as usual early in the course of schizophrenia predominantly improves negative symptoms. The present review summarizes the available data supporting the clinical testing of minocycline for patients with schizophrenia. In addition, we extend our discussion to the potential applications of minocycline for combining this treatment with cellular and molecular therapy.
Tenomodulin Expression in the Periodontal Ligament Enhances Cellular Adhesion
Yuske Komiyama, Shinsuke Ohba, Nobuyuki Shimohata, Keiji Nakajima, Hironori Hojo, Fumiko Yano, Tsuyoshi Takato, Denitsa Docheva, Chisa Shukunami, Yuji Hiraki, Ung-il Chung
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0060203
Abstract: Tenomodulin (Tnmd) is a type II transmembrane protein characteristically expressed in dense connective tissues such as tendons and ligaments. Its expression in the periodontal ligament (PDL) has also been demonstrated, though the timing and function remain unclear. We investigated the expression of Tnmd during murine tooth eruption and explored its biological functions in vitro. Tnmd expression was related to the time of eruption when occlusal force was transferred to the teeth and surrounding tissues. Tnmd overexpression enhanced cell adhesion in NIH3T3 and human PDL cells. In addition, Tnmd-knockout fibroblasts showed decreased cell adhesion. In the extracellular portions of Tnmd, the BRICHOS domain or CS region was found to be responsible for Tnmd-mediated enhancement of cell adhesion. These results suggest that Tnmd acts on the maturation or maintenance of the PDL by positively regulating cell adhesion via its BRICHOS domain.
The Role of NF-κB Signaling in the Maintenance of Pluripotency of Human Induced Pluripotent Stem Cells
Osamu Takase, Masahiro Yoshikawa, Mana Idei, Junichi Hirahashi, Toshiro Fujita, Tsuyoshi Takato, Takayuki Isagawa, Genta Nagae, Hirofumi Suemori, Hiroyuki Aburatani, Keiichi Hishikawa
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0056399
Abstract: NF-κB signaling plays an essential role in maintaining the undifferentiated state of embryonic stem (ES) cells. However, opposing roles of NF-κB have been reported in mouse and human ES cells, and the role of NF-κB in human induced pluripotent stem (iPS) cells has not yet been clarified. Here, we report the role of NF-κB signaling in maintaining the undifferentiated state of human iPS cells. Compared with differentiated cells, undifferentiated human iPS cells showed an augmentation of NF-κB activity. During differentiation induced by the removal of feeder cells and FGF2, we observed a reduction in NF-κB activity, the expression of the undifferentiation markers Oct3/4 and Nanog, and the up-regulation of the differentiated markers WT-1 and Pax-2. The specific knockdown of NF-κB signaling using p65 siRNA also reduced the expression of Oct3/4 and Nanog and up-regulated WT-1 and Pax-2 but did not change the ES-like colony formation. Our results show that the augmentation of NF-κB signaling maintains the undifferentiated state of human iPS and suggest the importance of this signaling pathway in maintenance of human iPS cells.
Rational Surface Automorphisms with Positive Entropy
Takato Uehara
Mathematics , 2010,
Abstract: The aim of this paper is to construct many examples of rational surface automorphisms with positive entropy by means of the concept of orbit data. We show that if an orbit data satisfies some mild conditions, then there exists an automorphism realizing the orbit data. Applying this result, we describe the set of entropy values of the rational surface automorphisms in terms of Weyl groups.
Siegel Disks on Rational Surfaces
Takato Uehara
Mathematics , 2015,
Abstract: We show the existence of a rational surface automorphism of positive entropy with a given number of Siegel disks. Moreover, among automorphisms obtained from quadratic birational maps on the projective plane fixing irreducible cubic curves, we find out an automorphism of positive entropy with multiple Siegel disks.
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