Hitoshi Nohta

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A highly selective and simple fluorimetric liquid chromatographic method for the determination of triethylenetetramine (TETA), a therapeutic drug for Wilson's disease, in human and rabbit sera is described. This method is based on intramolecular excimer-forming fluorescence derivatization, which allows spectrofluorometric discrimination of polyamino(More)
A highly sensitive and selective fluorimetric determination method for dicarboxylic acids (C5-C12) has been developed. This method is based on an intramolecular excimer-forming fluorescence derivatization with a pyrene reagent, 4-(1-pyrene)butyric acid hydrazide (PBH), followed by reversed-phase liquid chromatography (LC). The carboxylic acids were(More)
The effects of acute physiological stressors (5 s tail pinch, handling and forced swimming at +25 and +5 degrees C for 3 min each) on serotonin (5-HT) release in the mouse brain were investigated using in vivo microdialysis. The extracellular 5-HT levels were determined by a newly developed highly-sensitive and selective high-performance liquid(More)
A high-sensitive liquid chromatographic method based on precolumn derivatization and fluorescence detection allowing simultaneous determination of serotonin (5-HT), noradrenaline (NA) and dopamine (DA) in brain microdialysis samples is described. 5-HT, NA and DA were derivatized with benzylamine and 1,2-diphenylethylenediamine in the presence of potassium(More)
A highly sensitive method for the assay of catechol-O-methyltransferase in erythrocytes is described, which employs high-performance liquid chromatography with fluorescence detection. A newly synthesized catechol compound, 2-(3,4-dihydroxyphenyl)naphtho [1,2-d]thiazole is used as a highly fluorogenic substrate for catechol-O-methyltransferase; the m- and(More)
A microbore column liquid chromatographic method for the simultaneous determination of norepinephrine (NE), serotonin (5-HT), and 5-hydroxyindole-3-acetic acid (5HIAA) in microdialysis samples from rat brain is described. The method is based on precolumn derivatization of NE, 5HT, and 5HIAA with benzylamine in the presence of potassium hexacyanoferrate(III)(More)
A high-performance liquid chromatographic method using fluorescence detection for assessing the activity of aromatic L-amino acid decarboxylase in human plasma is described. Dopamine, formed enzymatically from L-DOPA, and isoproterenol (internal standard) are chromatographed on a small ion-exchange cartridge (Toyopak SP) and derivatized with(More)
This paper describes a sensitive and selective liquid chromatographic method with fluorescence detection for determination of histamine in brain microdialysis samples from awake rats. Samples containing histamine (10 microl) were derivatized with 20 microl of the reagent consisting of 3 mM 4-(1-pyrene)butyric acid N-hydroxysuccinimide ester (PSE), 3 mM(More)
A highly selective and sensitive method for the simultaneous determination of 5-hydroxyindoles and catechols (serotonin, norepinephrine, dopamine and related compounds) by high-performance liquid chromatography with fluorescence detection is described. The method is based on the two-step precolumn derivatization of 5-hydroxyindoles and catechols with(More)
A liquid chromatographic (LC) method for sensitive and selective fluorometric determination of p-hydroxyphenylethylamino group containing compounds is described. This method is based on an intramolecular excimer-forming fluorescence derivatization with a pyrene reagent, 4-(1-pyrene)butanoyl chloride, followed by reversed-phase LC. The analytes, containing(More)