Akiko Hamada

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Glycine betaine is believed to be the most active naturally occurring osmoprotectant molecule for Escherichia coli and other bacteria. It is a dipolar ion possessing a quaternary ammonimum group and a carboxylic acid group. To examine the molecular requirements for osmoprotective activity, dimethylthetin was compared with glycine betaine. Dimethylthetin is(More)
The isothiocyanate analog (IBI) of tolazoline produced contraction of the rat aortic strip, with an ED50 value of 1.63 x 10(-5) M. The maximum contraction of the analog was nearly equal to that of tolazoline or phenylephrine. At 27 degrees C the tissue reactivity of phenylephrine and IBI was similar. When compared at equiactive concentrations, the total(More)
The in vivo measurement of nitroxide radicals in whole mouse was carried out by L-band ESR spectroscopy. Spectra were successively observed in hepatic and bladder domains of female mice after intravenous administration of spin-labeled compounds (CPROXYL or TEMPOL). The signal intensities from both domains decreased gradually. The kinetic constants of(More)
In vivo EPR measurements were carried out with whole mice to evaluate the influence of inspired oxygen and ischemia-reperfusion injury on spin-clearance of the nitroxide radicals which were administered intravenously or intramuscularly. Nitroxide radicals in head, abdomen, or muscle domains were composed of sharp triplet lines. The peak heights decreased(More)
The epinephrine (EPI) stereoisomers interact with the alpha adrenoreceptor according to the Easson-Stedman model with an order of potency of (-)-EPI greater than (+)-EPI = Epinine. A series of catecholimidazolines (CI) and catecholamidines (CA) were compared with the EPI series for the relationship of stereoisomerism to potency, affinity and efficacy.(More)
Adrenoceptor-mediated effects of the enantiomers of optically active imidazoline, 2-(3,4,alpha-trihydroxybenzyl imidazoline (catecholimidazoline; CI), and norepinephrine (NE), and the corresponding desoxy derivatives, 2-(3,4-dihydroxybenzyl)imidazoline (desoxy-CI) and dopamine, have been investigated in human platelets. Differences between responsiveness of(More)
Reduction of radicals in mouse lung was characterized in whole animals using an L-band ESR technique and nitroxide radicals as probes. An aqueous solution of nitroxide radical was immediately instilled intratracheally to mouse after euthanasia. Nitroxide radicals without charged groups were reduced significantly in the lung, while radicals with charged(More)
The effects of oxygen on the metabolism of lipophilic nitroxide and the membrane structure of microsomes were investigated with an ESR spectrometer equipped with a hand-made gas-permeable sampling tube. The half life of gas change in the membrane was confirmed to be 48 s by the line-width of the ESR signal. The signal intensity of lipophilic nitroxide in(More)
The interaction of saponins with phospholipid vesicles was investigated by means of liposomal agglutination or a precipitation assay. Ginsenoside-Rc, which has an alpha-L-arabinofuranose residue at the non-reducing terminus, exhibited remarkable agglutinability toward egg yolk phosphatidylcholine vesicles, while other saponins lacking this characteristic(More)
A macroglycolipid containing galactose and N-acetylglucosamine as predominant sugar constituents was prepared together with glycophorin from rabbit erythrocyte membranes by extraction with lithium diiodosalicylate and partition in aqueous phenol. The macroglycolipid was effectively separated from the glycophorin fraction by ion-exchange chromatography in(More)