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101.
102.
HPLC analysis of pheomelanin degradation products in human urine 总被引:1,自引:0,他引:1
Takasaki A Nezirević D Arstrand K Wakamatsu K Ito S Kågedal B 《Pigment cell research / sponsored by the European Society for Pigment Cell Research and the International Pigment Cell Society》2003,16(5):480-486
A sensitive and specific high performance liquid chromatography (HPLC) method was developed to quantify 4-amino-3-hydroxyphenylalanine (4-AHP) and 3-amino-4-hydroxyphenylalanine (3-AHP) in urine. In degradation studies of melanin pigment, 4-AHP and 3-AHP are derived from benzothiazine units of pheomelanin and pheomelanin-related metabolites such as trichochromes. 5-S-Cysteinyldopa-derived benzothiazine products give 4-AHP while 2-S-cysteinyldopa-derived benzothiazine products give 3-AHP. 3-AHP is also derived from nitrotyrosine formed by nitration of tyrosine with reactive nitrogen species. For this reason, the influence of this biological process on the amount of 3-AHP found in biological material have been investigated. The method is based on hydriodic acid hydrolysis of the melanin polymer and reversed-phase HPLC with electrochemical detection of the degradation products 4-AHP and 3-AHP. The mobile phase consists of 25 mM ammonium acetate and sodium octanesulfonate as an ion-pairing reagent. The 4-AHP and 3-AHP peaks were well separated and the detector response was linear within the range 0-2 ng injected for both compounds. With the developed chromatographic system, 4-AHP and 3-AHP showed good separation in the biological samples. There was a strong correlation between 4-AHP and 3-AHP in the urine of 50 malignant melanoma patients and two healthy subjects (R0.977). The two compounds were also strongly correlated with 5-S-cysteinyldopa in urine, the correlation coefficients being 0.862 and 0.907, respectively. The method described is sensitive enough for analysis of pheomelanin in urine and in several other biological samples. The results indicate that 3-AHP in urine is not influenced by excreted 3-nitrotyrosine and the data indicate that pheomelanins are excreted in the urine of melanoma patients. 相似文献
103.
Kubo I Kinst-Hori I Nihei K Soria F Takasaki M Calderón JS Céspedes CL 《Zeitschrift für Naturforschung. C, Journal of biosciences》2003,58(9-10):719-725
As a defense mechanism of the leaves of Rhus javanica (Anacardiaceae) against the aphid Melaphis chinensis (Aphididae) attack, tannic acid is rapidly accumulated and forms galls along the midrib of the leaves resulting in a unique natural medicine Gallae Rhois. Tannic acid was found to inhibit the oxidation of L-3,4-dihydroxyphenylalanine (L-DOPA) catalyzed by tyrosinase (EC 1.14.18.1) with an IC50 of 22 microM. The aphid would detoxify the ingested toxic tannic acid to relatively nontoxic gallic acid, whereas the non-adapted pink bollworm Pectinophora gossypiella larvae are sensitive to the ingested tannic acid. 相似文献
104.
Takasaki Y Loy SF Juergens HW 《Journal of PHYSIOLOGICAL ANTHROPOLOGY and Applied Human Science》2003,22(5):233-235
The present study compared the regression equations of bioelectrical impedance on body size among various groups to investigate potential differences due to ethnicity. Data consisted of 30 Japanese and 28 Caucasoid subjects, and other groups of Aborigines, Danes, Melanesians and Polynesians from literature. The relationship between impedance and body weight fot the groups showed the ethnic difference. In the regression equations for Japanese and Caucasoid, a statistically significant difference was observed between both groups. The regression equation for Japanese was lower in the elevation. This seemed to be attributable to differences in the volume of fat-free mass for the same body build, configuration of the body, and fat-free mass density. 相似文献
105.
Flocculation properties of pectin in various suspensions 总被引:5,自引:0,他引:5
Pectin had a flocculating activity and its flocculating activities in various suspensions were investigated. Flocculating activity of pectin in a kaolin suspension was markedly stimulated by the addition of Al3+ and Fe3+ to the suspension. Optimum temperature for flocculating activity of pectin in the kaolin suspension was around 30 degrees C and high flocculating activity was obtained when 30 mg/l of pectin and 0.2 mM Fe3+ were added to the suspension. Other inorganic suspensions of activated carbon and acid clay were flocculated by pectin in the presence of Al3+ or Fe3+. Flocculation of organic suspensions such as cellulose and yeast by pectin occurred when 0.1-0.2 mM Fe3+ was present in the suspensions. 相似文献
106.
Miyamoto K Kodera N Umekawa H Furuichi Y Tokita M Komai T 《International journal of biological macromolecules》2002,30(3-4):205-212
Cryogel is a physical gel formed by heterophilic aggregation of extra domain A containing fibronectin [EDA(+)FN], plasma fibronectin (pFN), fibrinogen (Fbg) and heparin (Hep), which are found in high concentrations in the blood of patients suffering from rheumatoid arthritis. In this study, we clarify the specific interactions between cryogel components in terms of the affinity constant (K(A)), obtained by surface plasmon resonance (SPR). It is found that Fbg self-interactions occur at lower temperatures, and that K(A) of Fbg-Hep changes with temperature. Specifically, K(A) (2.0 x 10(8) [M(-1)]) of Fbg-Hep at 5 degrees C increases significantly from that (1.0x10(7) [M(-1)]) at 40 degrees C. K(A) of EDA(+)FN-Hep increases with temperature, by approximately 100-fold between 40 degrees C (K(A)=10(12) [M(-1)]) and 20 degrees C (K(A)=10(10) [M(-1)]). Although K(A) of the FN fragments of Hep-binding domain containing an EDA region [EDA(+)HBD(+)] and Hep increases with temperatures above 30 degrees C, K(A)s of HBD(+)-Hep and EDA(+)-Hep are not temperature-dependent. Therefore, EDA(+)HBD(+), formed as a special structure for high Hep affinity, exhibits temperature-dependent interaction with Hep. These results suggest that the main role of EDA(+)FN in cryogelation is to support the interaction with Hep. 相似文献
107.
Etsuko Mori Jerry L Hedrick Nate J Wardrip Tsuneatsu Mori Seiichi Takasaki 《Glycoconjugate journal》1998,15(5):447-456
Structures of acidic N-glycans released from porcine zona pellucida glycoproteins by hydrazinolysis were studied. The results indicated that the acidic glycans are of mono- to tetraantennary complex-type with and without N-acetyllactosamine repeating units. Sulfated residues are not only located at the C-6 position of GlcNAc included in the N-acetyllactosamine repeating units, but also at the C-6 position of GlcNAc in the non-repeated antennae and at the C-3 position of reducing terminal GlcNAc residue. Analysis of the oligosaccharide fragments released by endo--galactosidase digestion and by hydrazine/nitrous acid treatment also revealed that various sulfated and non-sulfated forms of fucosylated structures such as Fuc12Gal14(±SO–36)GlcNAc (type 2H), Gal14(Fuc13)(±SO–36)GlcNAc(Lex) and Fuc13 or 4(±SO–36)GlcNAc, are expressed in the repeated outer chain moieties. 相似文献
108.
109.
Shigeo Uehara Toshisada Nishida Hiroyuki Takasaki Mahale Mountains Wildlife Kohshi Norikoshi Takahiro Tsukahara Ramadhani Nyundo Miya Hamai 《Primates; journal of primatology》1994,35(3):275-281
K Group, originally one of the two major study groups of chimpanzees since 1965 in the Mahale Mountains National Park, western
Tanzania, was almost extinct by 1983: at most seven individuals remained in the group at the beginning of 1983. K Group continued
to exist for more than four years, but in 1987 a male was left alone at the age of 15 after all the other chimpanzees of the
group emigrated or disappeared. Since then he has been observed sporadically for more than five years only within the former
range of K Group, without having any contact with the many resident chimpanzees of the neighboring M Group, the other major
study group. The present observations reconfirm the strong philopatric tendency of adult male chimpanzees. 相似文献
110.
Development of medium components for the production of glucosyl-transferring enzyme by Aureobasidium
S. Hayashi T. Hinotani T. Hayashi Y. Takasaki K. Imada 《World journal of microbiology & biotechnology》1993,9(2):248-250
Aureobasidium sp. ATCC 20524 produced a glucosyl-transferring enzyme which produced panose (O--D-glucopyranosyl-(1»6)-O--D-glucopyranosyl-(1»4)-d-glucose) from maltose. Optimum production for the enzyme was with maltose at 2% (w/v) and yeast extract at 1.5% (w/v). Enzymatic activity reached 0.7×103 U/g dry cells after 48 h. 相似文献