528 research outputs found

    Honesty mediates the relationship between serotonin and reaction to unfairness

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    How does one deal with unfair behaviors? This subject has long been investigated by various disciplines including philosophy, psychology, economics, and biology. However, our reactions to unfairness differ from one individual to another. Experimental economics studies using the ultimatum game (UG), in which players must decide whether to accept or reject fair or unfair offers, have also shown that there are substantial individual differences in reaction to unfairness. However, little is known about psychological as well as neurobiological mechanisms of this observation. We combined a molecular imaging technique, an economics game, and a personality inventory to elucidate the neurobiological mechanism of heterogeneous reactions to unfairness. Contrary to the common belief that aggressive personalities (impulsivity or hostility) are related to the high rejection rate of unfair offers in UG, we found that individuals with apparently peaceful personalities (straightforwardness and trust) rejected more often and were engaged in personally costly forms of retaliation. Furthermore, individuals with a low level of serotonin transporters in the dorsal raphe nucleus (DRN) are honest and trustful, and thus cannot tolerate unfairness, being candid in expressing their frustrations. In other words, higher central serotonin transmission might allow us to behave adroitly and opportunistically, being good at playing games while pursuing self-interest. We provide unique neurobiological evidence to account for individual differences of reaction to unfairness

    Annexin A5 involvement in bone overgrowth at the enthesis

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    Little is known about the molecular mechanisms of enthesis formation in mature animals. Here, we report that annexin A5 (Anxa5) plays a critical role in the regulation of bone ridge outgrowth at the entheses. We found that Anxa5 is highly expressed in the entheses of postnatal and adult mice. In Anxa5‐deficient (Anxa5–/–) mice, the sizes of bone ridge outgrowths at the entheses of the tibiae and femur were increased after 7 weeks of age. Bone overgrowth was not observed at the fibrous enthesis where the fibrocartilage layer does not exist. More ALP‐expressing cells were observed in the fibrocartilage layer in Anxa5–/– mice than in wild‐type (WT) mice. Calcein and Alizarin Red double labeling revealed more mineralized areas in Anxa5–/– mice than WT mice. To examine the effects of mechanical forces, we performed tenotomy in which transmission of contractile forces by the tibial muscle was impaired by surgical muscle release. In tenotomized mice, bone overgrowth at the enthesis in Anxa5–/– mice was decreased to a level comparable to that in WT mice at 8 weeks after the operation. The tail‐suspended mice also showed a decrease in bone overgrowth to similar levels in Anxa5–/– and WT mice at 8 weeks after hindlimb unloading. These results suggest that bone overgrowth at the enthesis requires mechanical forces. We further examined effects of AnxaA5 gene knockdown (KD) in primary cultures of osteoblasts, chondrocytes, and tenocytes in vitro. AnxaA5 KD increased ALP expression in tenocytes and chondrocytes but not in osteoblasts, suggesting that increased ALP activity in the fibrocartilaginous tissue in AnxaA5 KO mice is directly caused by Anxa5 deletion in tenocytes or fibrocartilage cells. These data indicate that Anxa5 prevents bone overgrowth at the enthesis, whose formation is mediated through mechanical forces and modulating expression of mineralization regulators

    Immunohistochemical detection of methylated histone H3 lysine 9 and histone methyltransferases and implication of their roles during skeletal cell differentiation

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    早大学位記番号:新6540博士(人間科学)早稲田大

    Mid- term results of stryker® scorpio plus mobile bearing total knee arthroplasty

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    BACKGROUND: The mobile bearing knee system was introduced to lessen contact stress on the articular bearing surface and reduce polyethylene wear. The purpose of the current study was to investigate the mid-term results of patients undergoing total knee arthroplasties (TKAs) using Scorpio Plus Mobile Bearing Knee System (Stryker, Mahwah, NJ), and compare the outcomes between patients with osteoarthritis and osteonecrosis (OA·ON group) and patients with rheumatoid arthritis (RA group). METHODS: Eight males and 58 females were followed up for a period of 4.4- 7.6 years from June 1, 2003 to December 31, 2005. There were 53 knees with osteoarthritis, 17 knees with rheumatoid arthritis, and 6 knees with osteonecrosis. Clinical and radiographic follow- up was done using The Japanese Orthopedic Association knee rating score (JOA score) and Knee Society Total Knee Arthroplasty Roentgenographic Evaluation and Scoring System. RESULTS: With regard to the JOA score, there was significant improvement in both groups. The postoperative range of motion was between 0.8°and 116.8° in OA·ON group, and between 0.0° and 113.7° in RA group. There were no significant differences with the radiographic evaluation between two groups. Spontaneous dislocation of a polyethylene insert occurred in one patient, and deep infection was occurred in one patient. CONCLUSION: There was significant improvement with regard to the clinical and radiographic results of patients undergoing TKAs using the model. The risk of polyethylene insert dislocation related to the mobile bearing TKA is a cause for concern
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