Shoichiro Asayama

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The complex between manganese (Mn) porphyrins and catalase-poly(ethylene glycol) (PEG) conjugates has been designed for the protective effect against hepatic ischemia/reperfusion injury in vivo. The resulting Mn-porphyrin/catalase-PEG complex with dual enzymatic activity of superoxide dismutase (SOD) and catalase enhanced the blood circulation. The spin(More)
Mice lacking manganese-superoxide dismutase (Mn-SOD) activity exhibit typical pathology of dilated cardiomyopathy (DCM). In the present study, the structure-activity relationship between the water-soluble manganese (Mn) porphyrin with SOD activity and the in vivo pharmaceutical effect on DCM is reported. The Mn-SOD-deficient mice were treated with(More)
The poly(1-vinylimidazole) (PVIm) with sever al alkyl groups has been synthesized as a new pH-sensitive DNA carrier. The resulting alkylaed PVIm (PVIm-R) was water -soluble in spite of the hydrophobic alkyl groups and the deprotonation of the imidazole groups at physiological pH. Hemolysis assay showed the PVIm-R enhanced membrane disruptive ability at(More)
Liver sinusoidal endothelial cells (SECs) possess unique receptors that recognize and internalize hyaluronic acid (HA). To develop a system for targeting foreign DNA to SECs, comb-type polycations having HA side chains were prepared by coupling HA to poly(L-lysine) (PLL). The HA-grafted-PLL copolymer (PLL-g-HA) thus formed was mixed with DNA in 154 mM NaCl(More)
The complex comprising a cationic Mn-porphyrin and carboxymethyl poly(1-vinylimidazole) (CM-PVIm) was prepared as an artificial active center of catalase. Interestingly, the catalase activity of the complex depends on the chain length of the polymer and the chemical structure of Mn-porphyrin. This study is one step forward in the development of a new class(More)
Superoxide dismutase (SOD) and catalase activities of a drug are of great importance for its effective protection against reactive oxygen species (ROS)-induced injury. Achievement of catalase activity of a synthetic compound remains a challenge. Water-soluble Mn-porphyrins have high SOD and peroxynitrite (ONOO(-)) reducing activities, but not catalase-like(More)
A new design of antioxidant, consisting of manganese (Mn) porphyrin and signal peptide for mitochondrial targeting, is reported. The resulting Mn-porphyrin-oligopeptide conjugate exhibited significant superoxide dismutase (SOD) activity and decomposed peroxynitrite (ONOO-). The new antioxidant caused the swelling of isolated mitochondria. By using the(More)
The cell viability of human cancer cell lines treated with [5,10-bis(N-methyl-4-pyridyl)-15,20-diphenyl]porphinatoiron(III) (cis-FeMPy(2)P(2)P) has been estimated. The cis-FeMPy(2)P(2)P is a superoxide dismutase (SOD) mimic in vitro that exhibited a significant toxicity in cancer cell lines. This toxicity is rather due to pro-oxidant properties of the(More)
Carboxymethyl poly( l-histidine) (CM-PLH) as a new pH-sensitive polypeptide has enhanced polyplex gene delivery. Agarose gel retardation assay and zeta potential measurement proved that the anionic CM-PLH at physiological pH coated the PEI/DNA binary complexes. The resulting CM-PLH/PEI/DNA ternary complexes showed the gene expression value 300 times higher(More)
Poly(1-vinylimidazole) (PVIm) with alkylated imidazole groups has been synthesized as a pH-sensitive polycation to control the stability of its DNA polyion complexes for gene delivery. The resulting alkylated PVIm (PVIm-R) was water-soluble despite deprotonation of the imidazole groups at physiological pH, as determined by acid-base titration and solution(More)