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Straub PB Jaffe DE Glass HD Adams MR Brown CN Charpak G Cooper WE Crittenden JA Finley DA Gray R Hemmi Y Hsiung YB Hubbard JR Jonckheere AM Jöstlein H Kaplan DM Lederman LM Luk KB Maki A Mangeot P McCarthy RL Miyake K Plaag RE Rutherfoord JP Sakai Y Santiard JC Sauli F Smith SR Yoshida T Young KK 《Physical review letters》1992,68(4):452-455
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Ogata M Kaneya D Shin-Ya K Li L Abe Y Katoh H Seki S Seki Y Gonda R Urano S Endo T 《Chemical & pharmaceutical bulletin》2005,53(9):1167-1170
Many researchers have stated that eugenol might inhibit lipid peroxidation at the stage of initiation, propagation, or both, and many attempts have been made to elucidate the mechanism of its antioxidant activity. Nevertheless, details of its mechanism are still obscure. This study was carried out to investigate the trapping effect of eugenol on hydroxyl radical generated from L-3,4-dihydroxyphenylalanine (DOPA) in MiliQ water and the generation mechanism of the hydroxyl radical by this system which uses no metallic factor. This was studied by adding L-DOPA and 5,5-dimethyl-1-pyrroline N-oxide (DMPO) to phosphate buffered saline (PBS) or MiliQ water, and the generation of hydroxyl radical was detected on an ESR spectrum. By this method, the effect of antioxidants was detected as a modification of ESR spectra. We found that the eugenol trapped hydroxyl radicals directly, because it had no iron chelating action, did not trap L-DOPA semiquinone radical and inhibited hydroxyl radicals with or without iron ion. 相似文献
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Tunable diode laser spectra have been measured for the ν4 band of cis-HONO near 850 cm?1 and the ν2 band of rans-HONO near 1700 cm?1. The ν4 band is completely unperturbed and 355 well-resolved transitions have been fit with a standard deviation of 0.0007 cm?1. The ν2 band appears to have some small perturbations, but about 190 transitions have been fit with a standard deviation of 0.0027 cm?1. Rotational and centrifugal distortion constants are given for both bands. 相似文献
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Estimation of catecholamines in human plasma by ion-exchange chromatography coupled with fluorimetry
Estimation of catecholamines in human plasma was made by ion-exchange chromatography coupled with fluorimetry. Catecholamines in deproteinized plasma were adsorbed onto Amberlite CG-50 (pH 6.5, buffered with 0.4 M phosphate buffer) and selectively eluted by 0.66 M boric acid. The catecholamine fraction was separated further on a column of Amberlite IRC-50 which was coupled with a device for the automated performance of the trihydroxyindole method (epinephrine and norepinephrine) or the 4-aminobenzoic acid-oxidation method (dopamine). One sample could be analysed within 25 min with either method. The lower detection limits were 0.02 ng for epinephrine and dopamine, and 0.04 ng for norepinephrine. Plasma catecholamine contents of healthy adults at rest were epinephrine 0.07 +/- 0.01 ng/ml (n = 19), norepinephrine 0.27 +/- 0.03 ng/ml (n = 19) and dopamine 0.22 +/- 0.03 ng/ml (n = 26). The procedure of adsorption and elution of the plasma catecholamines by ion-exchange resin was simple, the simplicity contributing to constant recovery. The catecholamine fraction could be analysed without evaporation of the eluate. The analytical column could be used for the analysis of more than 1000 samples before excessive back-pressure developed. Our method of continuous measurement of plasma catecholamine fulfils clinical requirements. 相似文献
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The present work describes the synthesis of the beta-isomer of 1-alpha-D-(5-deoxy-5-iodoarabinofuranosyl)-2-nitroimidazole (IAZA). Radioiodinated IAZA ((123)I-IAZA) has been extensively studied as a radiopharmaceutical for the diagnosis of regional and/or focal tissue hypoxia in a variety of clinical pathologies. The beta-anomer of IAZA, 1-beta-D-(5-deoxy-5-iodoarabinofuranosyl)-2-nitroimidazole (beta-IAZA, 1), was synthesized via an unconventional route starting from 1-beta-D-(ribofuranosyl)-2-nitroimidazole (AZR), with a change of configuration at the C-2'-position to afford 1-beta-D-(arabinofuranosyl)-2-nitroimidazole (beta-AZA, 7). Nucleophilic iodination of the 5'-O-toluenesulfonyl-2',3'-di-O-acetyl precursor of beta-AZA, 9, followed by deprotection, afforded 1 in satisfactory yield. beta-IAZA (1) was also synthesized from 7 using molecular iodine and triphenylphosphine. 相似文献