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Dive into the research topics where Yasuharu Hakamatsuka is active.

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Featured researches published by Yasuharu Hakamatsuka.


Journal of Nanomaterials | 2013

β-tricalcium phosphate micron particles enhance calcification of human mesenchymal stem cells in vitro

Yusuke Nakagawa; Kunikazu Tsuji; Shizuko Ichinose; Yasuharu Hakamatsuka; Hideyuki Koga; Ichiro Sekiya

β-Tricalcium phosphate (β-TCP) micron particles whose diameters range from 1 µm to 10 µm have been recently developed, however, their biological effects remain unknown. We investigated the biological effects of β-TCP micron particles on proliferation, cytotoxicity, and calcification of human synovial mesenchymal stem cells (MSCs). MSCs were cultured without dexamethasone, β-glycerophosphate, or ascorbic acid. 1.0 mg/mL β-TCP micron particles inhibited proliferation of MSCs significantly and increased dead cells. In the contact condition, 0.1mg/mL β-TCP micron particles promoted calcification of MSCs evaluated by alizarin red staining and enhancedm RNA expressions of runx2, osteopontin, and type I collagen. In the noncontact condition, these effects were not observed. 0.1 mg/mL β-TCP micron particles increased calcium concentration in the medium in the contact condition, while 1.0 mg/mL β-TCP micron particles decreased calcium and phosphorus concentrations in the mediumin the noncontact condition. By transmission electron microscopy, β-TCP micron particles were localized in the phagosome of MSCs and were dissolved. In conclusion, β-TCP micron particles promoted calcification of MSCs and enhanced osteogenesis-related gene expressions in vitro.


Journal of Biomedical Materials Research Part A | 2009

Locally applied TCP inhibits tumor growth via possible activation of macrophages

Yukiko Naito; Tomoko Nagata; Shigehiro Tachibana; Mari Okimoto; Naoki Ohara; Yasuharu Hakamatsuka; Jinyan Cheng

The aim of this study was to investigate whether beta-tricalcium phosphate (TCP) inhibits cancer growth, because TCP, a widely used bone replacement material, is known to attract immune cells. Human colon cancer (WiDr) cells were subcutaneously injected on the backs of nude mice, and tumor growth was observed. Seven days after the injection, five animals were implanted with TCP at the tumor sites, five animals were treated by a direct application of 0.12 mg cisplatin at the sites, and four animals were not treated, as a control. Tumor size on the 43rd day of implantation was 1173 mm(3) in the TCP group and was smaller than that in the control, 1621 mm(3). This inhibition was comparable to that with cisplatin. Furthermore, tumor-growing rate in the TCP group was significantly lower than that in the control group. Histopathological examination of the tumors showed migration of macrophages only in the TCP group, with TCP particles remaining at the implantation loci. There were no between-group differences in neutrophil infiltration and angiogenesis. In another series of in vitro experiments, a concentration-dependent increase in luminol chemiluminescence was observed in isolated human peripheral neutrophils incubated with TCP, and the chemiluminescence due to phagocytosis of opsonized zymosan in the presence of TCP occurred with a lower level of TCP than when the chemiluminescence was due to TCP alone. These results suggest that subcutaneously implanted TCP inhibits tumor growth of implanted WiDr cells, and that the activation by TCP of macrophages plays a role in that inhibition.


Archive | 2004

Material for repairing biological tissues and process for producing the same

Yasuharu Hakamatsuka; Yuji Takamiya; Katsuya Sadamori


Archive | 2008

Body tissue filling material and method for production thereof

Tomoaki Tamura; Yasuharu Hakamatsuka; Toshie Tsuchiya; Shigeyuki Wakitani


Archive | 2012

癌細胞抑制セラミックスおよび癌細胞抑制セラミックスの製造方法、骨腫瘍の治療方法、粒径1~10μmのβリン酸三カルシウム多孔体顆粒の使用

Itirou Sekiya; 一郎 関矢; 宗田 大; Yasuharu Hakamatsuka; 袴塚 康治


Archive | 2008

Körpergewebe-auffüllmaterial und herstellungsverfahren dafür

Shigeyuki Wakitani; Tomoaki Tamura; Yasuharu Hakamatsuka; Toshie Tsuchiya


Archive | 2006

Agent renforçant pour tissus biologiques, méthode de production dudit agent, emploi dudit agent et méthode de culture cellulaire

Toshie Tsuchiya; Masato Tamai; Yasuharu Hakamatsuka; Tomoaki Tamura


Archive | 2006

BIOLOGICAL TISSUE-REINFORCING MATERIAL, METHOD OF PRODUCING THE SAME, USE OF THE SAME, AND METHOD OF CULTURING CELLS

Toshie Tsuchiya; Masato Tamai; Yasuharu Hakamatsuka; Tomoaki Tamura


Archive | 2006

Reinforcing agent for biological tissue, method of producing the same, utilization of the same and method of culturing cells

Toshie Tsuchiya; Masato Tamai; Yasuharu Hakamatsuka; Tomoaki Tamura


Archive | 2006

Verstärkungsmittel für biologisches gewebe, verfahren zu seiner herstellung, seine verwendung und verfahren zur züchtung von zellen

Toshie Tsuchiya; Masato Tamai; Yasuharu Hakamatsuka; Tomoaki Tamura

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Shigeyuki Wakitani

Mukogawa Women's University

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Hideyuki Koga

Tokyo Medical and Dental University

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Ichiro Sekiya

Tokyo Medical and Dental University

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Kunikazu Tsuji

Tokyo Medical and Dental University

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