Masami Hashimoto

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Natural joints rely on fluid thin-film lubrication by the hydrated polyelectrolyte layer of cartilage. However, current artificial joints with polyethylene (PE) surfaces have considerably less efficient lubrication and thus much greater wear, leading to osteolysis and aseptic loosening. This is considered a common factor limiting prosthetic longevity in(More)
We have designed mitochondrially targeted transcription activator-like effector nucleases or mitoTALENs to cleave specific sequences in the mitochondrial DNA (mtDNA) with the goal of eliminating mtDNA carrying pathogenic point mutations. To test the generality of the approach, we designed mitoTALENs to target two relatively common pathogenic mtDNA point(More)
In a rat model of myocardial ischemic infarction, sodium orthovanadate rescued cells from ischemia/reperfusion injuries. Rats underwent 30 min of myocardial ischemia by occluding the left coronary artery followed by 24 h of reperfusion. Post-treatment with orthovanadate reduced infarct size in a dose-dependent manner. Orthovanadate treatment also(More)
Photo-induced graft polymerization of 2-methacryloyloxyethyl phosphorylcholine (MPC) on cross-linked polyethylene (CLPE) has been developed as a novel technology for reducing wear of orthopaedic bearings. In this study, the effect of MPC concentration on graft polymerization and the resultant properties of the grafted poly (MPC) layer have been(More)
We assumed that the extra energy supplied by gamma-ray irradiation produced cross-links in 2-methacryloyloxyethyl phosphorylcholine (MPC) polymer grafted cross-linked polyethylene (CLPE-g-MPC) and investigated its effects on the tribological properties of CLPE-g-MPC. In this study, we found that the gamma-ray irradiation produced cross-links in three kinds(More)
Photoinduced grafting of 2-methacryloyloxyethyl phosphorylcholine (MPC) onto cross-linked polyethylene (CLPE) was investigated for its ability to reduce the wear of orthopedic bearings. We investigated the effect of UV-irradiation intensity on the extent of poly(MPC) (PMPC) grafting, and found that it increased with increasing intensity up to 7.5 mW/cm(2),(More)
We investigated the production of free radicals on a poly(ether-ether-ketone) (PEEK) substrate under ultraviolet (UV) irradiation. The amount of the ketyl radicals produced from the benzophenone (BP) units in the PEEK molecular structure initially increased rapidly and then became almost constant. Our observations revealed that the BP units in PEEK acted as(More)
Surface modification is important for the improvement in medical device materials. 2-Methacryloyloxyethyl phosphorylcholine (MPC) polymers have attracted considerable attention as surface modifiable polymers for several medical devices. In this study, we hypothesize that the structure of the surface modification layers might affect the long-term stability,(More)
We here assessed the effects of 3-[2-[4-(3-chloro-2-methylphenyl)-1-piperazinyl]ethyl]-5,6-dimethoxy-1-(4-imidazolylmethyl)-1H-indazole dihydrochloride 3.5 hydrate (DY-9760e), a novel calmodulin antagonist, on infarct size in the rat heart subjected to ischemia/reperfusion. Rats were subjected to a 30-min coronary occlusion followed by a 24-h reperfusion.(More)
Initial cell responses following implantation are important for inducing osteoconductivity. We investigated cell adhesion, spreading, and proliferation in response to native and bovine serum albumin (BSA)-adsorbed disc of hydroxyapatite (HA) or alpha-type alumina (α-Al2O3) using mouse MC3T3-E1 osteoblastic cells and mouse RAW264.7 macrophages. The adsorbed(More)