Masanori Ando

Musashino University, Edo, Tōkyō, Japan

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Publications (94)225.38 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: The quantitative analysis of ketones using DNPH is usually conducted in the presence of an acid catalyst. However, this method may cause an analytical error because 2,4-dinitrophenylhydrazones have both E- and Z-stereoisomers. Purified ketone-2,4-dinitrophenylhydrazone comprised only the E-isomer. However, under the addition of acid, both E- and Z-isomers were seen. In the case of 2-butanone-, 2-pentanone- and 2-hexanone-2,4-dinitrophenylhydrazone, the equilibrium Z/E isomer ratios were 0.20, 0.21 and 0.22, respectively. In addition, when trace water was added to the hydrazone derivatives in acetonitrile solution, the concentration of ketone derivatives were seen to decrease and the concentration of free DNPH was seen to increase. The decomposition rate of 2-butanone-2,4-dinitrophenylhydrazone was dependent on the concentration of acid-catalysis and reached an equilibrium state--carbonyl, DNPH, hydrazone-derivative and H2O--within 10 h at 0.1 mol L(-1) phosphoric acid solution. The equilibrium constants of ketone-2,4-dinitrophenylhydrazones, [carbonyl] [DNPH]/[hydrazone] [H2O], were relatively large and ranged from 0.74x10(-4) to 5.9x10(-4). Hydrazone derivatives formed from 2-ketones such as 2-pentanone, 2-hexanone and 4-methyl-2-pentanone showed lower equilibrium constants than corresponding 3-ketones. Consequently, only a minimum concentration of catalytic acid must be added. The best method for the determination of ketone-2,4-dinitrophenylhydrazones by HPLC or GC is to add phosphoric acid to both the standard reference solution and samples, forming a 0.001 mol L(-1) acid solution, and analyze after 27 h.
    Analytica chimica acta 01/2008; 605(2):198-204. · 4.31 Impact Factor
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    ABSTRACT: The effects of natural compounds on reducing formaldehyde emission from plywood were investigated. Urea, catechin and vanillin were examined as the natural formaldehyde reducers. The microemission cell, with an internal volume of 35 ml, the maximum exposed test surface area of 177 cm2 and an air purge flow rate of 50 ml min−1, was used to measure specific emission rate (SER). In the case of no reducer treatment, formaldehyde emission from plywood was fast and SERs were 4.4 mg m−2 h−1 at 30 °C and 15 mg m−2 h−1 at 60 °C. When this plywood was treated with the natural compounds, the SERs of formaldehyde were decreased at all temperatures. In the case of urea treatment, the SERs of formaldehyde decreased to 0.30 mg m−2 h−1 at 30 °C and 0.65 mg m−2 h−1 at 60 °C. When the urea treatment was applied to the inside of kitchen cabinet (made from plywood; 270 cm wide, 60 cm deep, 250 cm high), the concentration of formaldehyde was reduced substantially from 1600 to 130 μg m−3. The reducing effect of formaldehyde continued during the observation period (6 months), with a mean concentration of 100 μg m−3. Reducers in the plywood would react with released formaldehyde. Application of natural compounds such as urea, catechin and vanillin could provide a simple and effective approach for suppressing formaldehyde emission from plywood.
    Atmospheric Environment. 01/2007;
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    ABSTRACT: A new method is described for the determination of orthophthalaldehyde in air which is used for the disinfection of various instruments (e.g. endoscopes) in hospital. Orthophthalaldehyde in air was collected with a silica gel cartridge impregnated with acidified 2,4-dinitrophenylhydrazine (DNPH-cartridge) and derivatives were analyzed by high-performance liquid chromatography (HPLC). In this study, the derivatization was examined by comparing the process with three phthalaldehyde isomers (ortho-, iso- and tere-). In the case of iso- and tere-phthalaldehyde, derivatives synthesized with excess of aldehyde consisted mainly of mono-derivatives, and derivatives synthesized with excess of DNPH consisted mainly of bis-derivative. In the case of orthophthalaldehyde, derivative consisted of only bis-derivative and mono-derivative was never observed under any conditions. Orthophthalaldehyde was completely retained by the DNPH-cartridge during air sampling, however, the derivatization reaction was incomplete and unreacted orthophthalaldehyde was flushed from the cartridge during the subsequent solvent extraction process. Unreacted orthophthalaldehyde and DNPH reacted again in the extraction solvent solution. Immediately after the solvent extraction, both mono- and bis-DNPhydrazone derivatives of orthophthalaldehyde were present in the solution. However, over time, the mono-derivative decreased and bis-derivative increased until only the bis-derivative was left allowing accurate determination of the orthophthalaldehyde concentration. The transformation of mono-derivative to bis-derivative was faster in polar aprotic solvents such as acetonitrile, dimethyl sulfoxide and ethyl acetate. Transformation was found to occur most quickly in acetonitrile solvent and was completed in 4 h in this case. It was possible to measure orthophthalaldehyde in air as bis-derivative using a DNPH impregnated silica cartridge and HPLC analysis.
    Journal of Chromatography A 06/2006; 1116(1-2):165-71. · 4.61 Impact Factor
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    ABSTRACT: To evaluate the main intake source of arsenic by the villagers from arsenic-affected families in Jalangi and Domkol blocks in Mushidabad district, West Bengal-India, we determined the concentrations of arsenic in tube-well water and in food composites, mainly including vegetables and cereals collected from the surveyed families which were cultivated in that region. The daily dietary intakes of arsenic by the villagers were estimated and the excretions of arsenic through urine and hair were determined. The arsenic concentrations in hair and urine of the studied population living in mild (2.78 microg/L), moderate (30.7 microg/L) and high (118 microg/L) arsenic-affected families were 133, 1,391 and 4,713 microg/kg and 43.1, 244 and 336 microg/L, respectively. The linear regressions show good correlations between arsenic concentrations in water vs hair (r(2)=0.928, p<0.001) and water vs urine (r(2)=0.464, p<0.01). Approximately 29.4%, 58.1% and 62.1% of adult population from mild, moderate and high arsenic-affected families were suffering from arsenical skin manifestations. The mean arsenic concentrations of food composites (vegetables and cereals) in high arsenic-affected families are not significantly different from mild arsenic-affected families. The daily dietary intakes of arsenic from water and food composites of the studied population, living in high, moderate and mild arsenic-affected families were 568, 228 and 137 microg, respectively. The linear regressions show good correlations between arsenic concentrations in hair vs daily dietary intake (r(2)=0.452, p<0.001) and urine vs daily dietary intake (r(2)=0.134, p<0.001). The water for drinking contributed 6.07%, 26.7% and 58.1% of total arsenic in our study from mild, moderate and high arsenic-affected families. The result suggested that the contaminated water from high arsenic-affected families should be the main source for intake of arsenic. On contrary, the contribution of arsenic-contaminated food composites from mild and moderate arsenic-affected families might be the main source for intake of arsenic. The Food and Agriculture Organization/World Health Organization (FAO/WHO) provisional tolerable weekly intake (PTWI) values of arsenic in our study were 3.32, 5.75 and 12.9 microg/kg body weight/day from mild, moderate and high arsenic-affected families, respectively, which is higher than the recommended PTWI value of arsenic (2.1 microg/kg body weight/day).
    Food and Chemical Toxicology 05/2006; 44(4):455-61. · 3.01 Impact Factor
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    ABSTRACT: We have performed two-stage transformation assay using BALB/c 3T3 cells to determine initiating and promoting activities of disodium arsenate, sodium arsenite, monomethylarsonic acid (MMAA) and dimethylarsinic acid (DMAA). Treatment with these arsenic compounds at the initiating stage induced significant numbers of transformed foci when cells were post-treated with 12-O-tetradecanoylphorbol-13-acetate (TPA). Disodium arsenate was active at the concentrations of 15-30 microM, sodium arsenite 5-20 microM, and DMAA 1-2 mM. MMAA required 10 mM to induce cell transformation. The concentrations of these compounds (except DMAA) that induced transformation were highly growth-inhibitory (more than 50%). DMAA induced transformation foci at growth inhibition levels of 66 to 84%. In experiments on promoting activity, cells pretreated with a sub-threshold dose of 20-methylcholanthrene (MCA, 0.2 microg/ml) or sodium arsenite (10 microM) were used. Transformation was enhanced by post-treatment with disodium arsenate (1-10 microM), sodium arsenite (0.5-2 microM), and MMAA (200-1000 microM), but not with DMAA. Studies of gap junctional intercellular communication using the V79 cell metabolic cooperation assay showed that the arsenic compounds (except DMAA) exhibited inhibitory activity. Thus, most arsenicals were shown to have not only initiating activity, but also promoting activity. In addition, inorganic arsenicals, especially trivalent sodium arsenite, were more active than organic ones and exhibited promoting activity at one-order of magnitude lower than initiating activity. These results suggest that from the viewpoint of human hazard, more attention should be paid to the tumor promoting activity of inorganic arsenic compounds.
    Toxicological Sciences 05/2005; 84(2):344-51. · 4.33 Impact Factor
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    ABSTRACT: Cytochrome P450 2C8 is one of the primary enzymes responsible for the metabolism of a wide range of drugs such as paclitaxel, cerivastatin, and amiodarone. We have sequenced the CYP2C8 gene from 201 Japanese subjects and found five novel nonsynonymous single nucleotide polymorphisms (SNPs): 511G>A (G171S), 556C>T (R186X; X represents the translational stop codon), 556C>G (R186G), 740A>G (K247R), and 1149G>T (K383N), with the allele frequency of 0.0025. The CYP2C8 variants were heterologously expressed in COS-1 cells and functionally characterized in terms of expression level, paclitaxel 6alpha-hydroxylase activity, and intracellular localization. The prematurely terminated R186X variant was undetectable by Western blotting and inactive toward paclitaxel 6alpha-hydroxylation. The G171S, K247R, and K383N variants exhibited properties similar to those of the wild-type CYP2C8. Paclitaxel 6alpha-hydroxylase activity of the R186G transfectant was only 10 to 20% that of wild-type CYP2C8. Furthermore, the R186G variant displayed a lower level of protein expression in comparison to the wild type, which was restored by the addition of a proteasome inhibitor (MG-132; Z-Leu-Leu-Leu-aldehyde). The reduced CO-difference spectral analysis using recombinant proteins from an insect cell/baculovirus system revealed that the R186G variant has a minor peak at 420 nm in addition to the characteristic Soret peak at 450 nm, suggesting the existence of improperly folded protein. These results indicate that the novel CYP2C8 SNPs, 556C>T (R186X) and 556C>G (R186G), could influence the metabolism of CYP2C8 substrates such as paclitaxel and cerivastatin.
    Drug Metabolism and Disposition 05/2005; 33(5):630-6. · 3.36 Impact Factor
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    ABSTRACT: A simple and rapid method has been developed for herbicides in water using temperature-responsive liquid chromatography (LC) and a column packed with poly(N-isopropylacrylamide) (PNIPAAm), a polymer anchored on the stationary-phase surface of modified silica. PNIPAAm reversibly changes its hydrophilic/hydrophobic properties in water in response to temperature. The method was used to determine five sulfonylurea and three urea herbicides. Separation was achieved with a 10 mM ammonium acetate (pH 3.0) isocratic aqueous mobile phase, and by changing the column temperature. The analytes were extracted from water by off-line solid-phase extraction (SPE) with an N-vinyl-pyrrolidone polymer cartridge. The average recoveries of the eight herbicides from spiked pure water, tap water and river water were 70-130% with relative standard deviations (RSDs) of <10%. The limits of quantitation (LOQ) of the eight herbicides were between 1 and 4 microg l(-1).
    Journal of Chromatography A 04/2005; 1069(2):281-5. · 4.61 Impact Factor
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    ABSTRACT: Total arsenic withdrawn by the four shallow tubewells, used for agricultural irrigation in the arsenic-affected areas of Murshidabad district per year is 6.79 kg (mean: 1.79 kg, range: 0.56-3.53 kg) and the mean arsenic deposition on land per year is 5.02 kg ha(-1) (range: 2-9.81 kg ha(-1)). Mean soil arsenic concentrations in surface, root of plants, below ground level (0-30 cm) and all the soils, collected from four agricultural lands are 14.2 mg/kg (range: 9.5-19.4 mg/kg, n = 99), 13.7 mg/kg (range: 7.56-20.7 mg/kg, n = 99), 14.8 mg/kg (range: 8.69-21 mg/kg, n = 102) and 14.2 mg/kg (range: 7.56-21 mg/kg, n = 300) respectively. Higher the arsenic in groundwater, higher the arsenic in agricultural land soil and plants has been observed. Mean arsenic concentrations in root, stem, leaf and all parts of plants are 996 ng/g (range: <0.04-4850 ng/g, n = 99), 297 ng/g (range: <0.04-2900 ng/g, n = 99), 246 ng/g (range: <0.04-1600 ng/g, n = 99) and 513 ng/g (range: <0.04-4850 ng/g, n = 297) respectively. Approximately 3.1-13.1, 0.54-4.08 and 0.36-3.45% of arsenic is taken up by the root, stem and leaf respectively, from the soil.
    Chemosphere 03/2005; 58(6):799-810. · 3.14 Impact Factor
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    ABSTRACT: Indoor air quality is currently a growing concern, mainly due to the incidence of sick building syndrome and building related illness. To better understand indoor air quality in Japan, both indoor and outdoor air samples were collected from 50 residences in Iwate, Yamanashi, Shiga, Hyogo, Kochi and Fukuoka Prefectures. More than 100 volatile organic compounds (VOCs) were analyzed by thermal desorption-gas chromatography/mass spectrometry method. The most abundant class of compounds present in the indoor air samples were identified (i.e. alkanes, alkylbenzenes and terpenes). For 30% of the indoor air samples, the sum of each VOC exceeded the current provisional guideline value for total VOC (TVOC, 400 microg/m3). The major component of these samples included linear and branched-chain alkanes (possibly derived from fossil fuels), 1,4-dichlorobenzene (a moth repellent), alpha-pinene (emission from woody building materials) and limonene (probably derived from aroma products). As an unexpected result, one residence was polluted with an extremely high concentration of 1,1,1,2-tetrafluoroethane (720 microg/m3), suggesting accidental leakage from a household appliance such as a refrigerator. The results presented in this paper are important in establishing the Japanese target compound list for TVOC analysis, as well as defining the current status of indoor air quality in Japan.
    Kokuritsu Iyakuhin Shokuhin Eisei Kenkyūjo hōkoku = Bulletin of National Institute of Health Sciences 02/2005;
  • Journal of Health Science - J HEALTH SCI. 01/2005; 51(4):514-517.
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    ABSTRACT: A new method for the simultaneous determination of aliphatic carboxylic acids and aldehydes in air is described. In this work, carboxylic acids were allowed to react with 2,4-dinitrophenylhydrazine (DNPH) to form the corresponding carboxylic 2,4-dinitrophenylhydrazides. These derivatives have excellent thermal stability, with melting points higher than those of the corresponding hydrazones by 32-50 degrees C. C1-C4 carboxylic acid 2,4-dinitrophenylhydrazides exhibited maximum absorption wavelengths of 331-334 nm and molar absorption coefficients of 1.4 x 10(4) L/mol/cm. They were completely separated by high-performance liquid chromatography (HPLC) with an RP-Amide C16 column. Cartridges packed with DNPH-coated silica particles (DNPH cartridge) were used for sampling formic acid and aldehydes. Formic acid was physically adsorbed on the silica particles as the first step of the sampling mechanism. Gradual reaction with DNPH followed. Formic acid reacted very slowly with DNPH at room temperature (20 degrees C), but reacted completely at 80 degrees C over 4 h. In field measurements, the sample air was drawn through a DNPH cartridge. After sampling, the cartridges were heated at 80 degrees C for 5 h and extracted with acetonitrile for HPLC analysis. Under these optimized conditions, the LOD is 0.4 ug/m(3) for an air sample collected for 24 h at 100 mL/min (144 L).
    Analytical Chemistry 11/2004; 76(19):5849-54. · 5.82 Impact Factor
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    ABSTRACT: Ishigami et al. (Ishigami et al., 1998) reported that squalene monohydroperoxide (SQOOH) induced skin damage in hairless mice. Kohno and Takahashi (Kohno and Takahashi, 1993) reported that SQOOH induced cytotoxicity against Chinese hamster lung fibroblasts. We have already evaluated the efficacy of extracts obtained from Brazilian herbal medicines in protecting the normal human epidermis keratinocytes [NHEK(B)] against the cytotoxicity caused by SQOOH. The EtOAc extract was separated by silica-gel column chromatography into eight fractions. Fractions (Fr) 1,3 and 5 significantly protected rat basophilic leukemia (RBL-2H3) cells from the release of beta-hexosaminidase due to SQOOH. Additionally, Fr5-1 was most effective in a Gunze three-dimensional cultured human skin model (Vitrolife-skin) against the cytotoxicity due to SQOOH and the release of interleukin (IL)-2 and IL-4. The mixture of cinchonains Ia and Ib and the mixture of cinchonains IIa and IIb were isolated from Fr3 and Fr5-1, respectively. The results suggest that the addition of SQOOH caused the reduction in cell viability and the release of beta-hexosaminidase and cytokines as chemical mediators. The extract of Catuaba (Anemopaegma mirandum) prevented these toxic effects with the main active agents suggested to be cinchonains IIa and IIb.
    Toxicology in Vitro 07/2004; 18(3):255-63. · 2.65 Impact Factor
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    ABSTRACT: A multianalyte method has been developed for the confirmation and quantitation of five sulfonylureas, bensulfuron-methyl, imazosulfuron, pyrazosulfuron-ethyl, flazasulfuron and halosulfuron-methyl, and for three ureas, siduron, dymron (daimuron) and diuron (DCMU) in water. Samples were extracted from water by off-line solid-phase extraction (SPE) with a polystyrene polymer cartridge (PS2), an ODS C18-bonded silica cartridge (C18) and an N-vinylpyrrolidone polymer cartridge (Oasis). Analyte determination and quantitation were performed by liquid chromatography with mass spectrometry (LC–MS). Extraction efficiency experiments demonstrated the ability of this method to extract sulfonylureas and ureas from water samples. Confirmatory analysis was carried out by LC-electrospray mass spectrometry (LC–ESI–MS) instrumentation equipped with a single-quadrupole mass filter. MS data acquisition was performed by a single or two-ion selected ion monitoring (SIM) program. It is required for confirmation that LC–MS retention times of the analytes are within 1% of the retention times of the standards, and that the molecular ion or characteristic fragment ion is present for each analyte. Fragment ions from distinctive structures must be obtained to identify and characterize specific herbicide molecules. These were obtained by controlled decomposition of sulfonylurea and urea adduct ions after suitably adjusting the electrical field in the desolvation chamber. The eight herbicides were also measured in fortified pure water (water purified by a milli-Q system), tap water and river water. Average recoveries of the eight analytes from water samples were in the range of 70–120% with relative standard deviations (R.S.D.s) of <20%. The limit of quantitation (LOQ) for each of the eight herbicides was between 10 and 100 ng l−1.
    Analytica Chimica Acta. 04/2004;
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    ABSTRACT: We have designed copolymers of N-isopropylacrylamide, environmentally-responsive polymers, which respond to temperature and other external stimuli. In this study, we designed and synthesized copolymers that introduced ion-exchange groups. These copolymers responded to the temperature and the pH, and the copolymer-grafted aminopropyl silica beads were used as HPLC packing materials. This stationary phase altered the properties from hydrophilic to hydrophobic and from charge to non-charge by temperature and pH changes. We studied the separations of organic acids and phenylthiohydantoin-amino acids using environmentally-responsive chromatography, and confirmed the effects of the ion-exchange groups. The elution behaviors of these samples were controlled by the temperature changes without organic solvents in the mobile phase. It was confirmed that the interactions between the solute and stationary phase could be freely controlled by the temperature and the pH. Environmentally-responsive chromatography is expected to be applicable to the separation of pharmaceuticals and biomolecules, such as peptides, proteins and nucleic acids.
    Journal of Chromatography A 04/2004; 1030(1-2):247-53. · 4.61 Impact Factor
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    ABSTRACT: Human constitutive androstane (or active) receptor (hCAR), a member of the nuclear receptor superfamily NR1I3, regulates the expression of several genes that are mainly involved in the metabolism of endogenous and xenobiotic compounds (e.g., CYP2B6, CYP3A4, and UGT1A1). We found four novel splice variants in the ligand-binding domain (LBD) of hCAR (NCBI reference sequence, NM_005122; designated SV0 herein). The variants designated SV1 and SV2 contained in-frame 12- and 15-base pair (bp) insertions, respectively. SV3 carried both of the insertions, and SV4 contained an in-frame 117-bp deletion. The insertion site of SV1 is located in the alpha6 helix of hCAR LBD, which makes up the ligand-binding cavity, and that of SV2 is located in the highly conserved loop between helices alpha8 and alpha9. SYBR Green real-time reverse transcription-polymerase chain reaction analysis of each splice variant revealed that the hepatic expression of SV2 was almost comparable with that of SV0 (approximately 40%), whereas other variants accounted for 6 to 10% of the total hCAR transcripts. In the reporter gene assays employing the phenobarbital-responsible enhancer module (PBREM) from CYP2B6 and UGT1A1 genes, the splice variants, except for SV1, were inactive, whereas SV1 transactivated the CYP2B6 PBREM but not the UGT1A1 PBREM reporter. A nuclear translocation assay in rat hepatocytes revealed that all the splice variants lack the responsiveness toward phenobarbital and 6-(4-chloropheny-l)imidazo[2,1-b][1,3]thiazole-5-carbaldehyde O-(3,4-dichlorobenzyl)oxime (CITCO) in terms of the ligand-dependent nuclear translocation. Further characterization, such as the identification of specific ligands, will help elucidate physiological implication of these hCAR splice variants.
    Molecular Pharmacology 04/2004; 65(3):496-502. · 4.41 Impact Factor
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    ABSTRACT: Carvedilol ((+/-)-1-carbazol-4-yloxy)-3-[[2-(o-methoxyphenoxy)ethyl]amino]-2-propanol) is metabolized primarily into glucuronide conjugates. In the present study, we identified the human UDP-glucuronosyltransferase (UGT) isoforms involved in the glucuronidation of carvedilol by thin-layer chromatography using microsomes from human liver or insect cells expressing recombinant UGT isoforms. We observed two forms of carvedilol glucuronides, namely G1 and G2, in hepatic microsomes. The glucuronidation of carvedilol was catalyzed by at least three recombinant UGT isoforms: UGT1A1, UGT2B4, and UGT2B7. UGT2B4 formed both G1 and G2, whereas UGT1A1 and UGT2B7 were responsible for the formation of glucuronide G2 and G1, respectively. The enzyme kinetics for carvedilol glucuronidation by UGT1A1, UGT2B4, and UGT2B7 in addition to human liver microsomes were examined by Lineweaver-Burk analysis. The values of Km and Vmax for human liver microsomes were 26.6 microM and 106 pmol/min/mg protein for G1, and 46.0 microM and 44.5 pmol/min/mg protein for G2, respectively. The Km values for UGT1A1, UGT2B4, and UGT2B7 for G1 and G2 (22.1-55.1 microM) were comparable to those of the liver microsomes, whereas the Vmax values were in the range of 3.33 to 7.88 pmol/min/mg protein. The Km and Vmax/Km values for UGT2B4 and UGT2B7 for G1 were similar, whereas UGT2B4 had lower Km and higher Vmax/Km values for G2 compared with those of UGT1A1. These results suggest that G1 formation is catalyzed by UGT2B4 and UGT2B7, whereas G2 is formed by UGT2B4 and UGT1A1. These three hepatic UGT isoforms may have important roles in carvedilol metabolism.
    Drug Metabolism and Disposition 03/2004; 32(2):235-9. · 3.36 Impact Factor
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    ABSTRACT: Tetracaine hydrochloride (TH) is nominated as the prohibited ingredients in cosmetics in Japanese Pharmaceutical Affairs Act. So the analytical method for TH was investigated by HPLC. After adding 5 ml of TH solution at 10 microg/ml and 2 ml of salicylic acid solution at 75 microg/ml as the internal standard to 0.5 g of the lotion, the mixture was made up to 10 ml with a mixture of water and methanol (1:1) as the testing solution. Milky lotion was procedured as follows: After adding 5 ml of TH solution at 10 microg/ml and 2 ml of internal standard solution to 0.5 g of the milky lotion, the mixture was made up to 10 ml with a mixture of water and methanol (1:1). Two milliliter of this mixture was placed into a centrifuging tube with a cap and 2 ml of hexane was added. After shaking vigorously and centrifuging, the lower layer was used as the testing solution. In the case of the cream, the other procedures were used: 0.5 g of cream was placed into a 10-ml volumetric flask and 1 ml of tetrahydrofuran was added. After dissolving, the mixture of methanol and water (1:1) was added to make up 10.0 ml. Two milliliter of this mixture was placed into a centrifuging tube with a cap and 2.0 ml of hexane was added. After shaking vigorously and centrifuging, the lower layer was used as the testing solution. The testing solution of 20 microl was analyzed by HPLC using the ODS column (CAPCELL PAK C18 column, 4.6 x 250 mm), the mixture of acetonitrile and 50 mmol/l phosphate buffer(pH 2.0)(7:3) and the detection wavelength of 303 nm. The working curves from 0.5 to 6.0 microg/ml showed a linear line between the concentrations of TH and the peak area ratio. There was no interference of peak of TH from the lotion, milky lotion and cream.
    Kokuritsu Iyakuhin Shokuhin Eisei Kenkyūjo hōkoku = Bulletin of National Institute of Health Sciences 02/2004;
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    ABSTRACT: Estriol (EO) is nominated as the prohibited ingredients in cosmetics in Japanese Pharmaceutical Affairs Act. So the analytical method using HPLC for EO was investigated. After placing 1.0 ml of EO solution at 50 microg/ml and 0.5 g of the lotion into a 10-ml volumetric flask, the methanol was added to make until that volume and this solution was used as the testing solution. Milky lotion was procedured as follows: After placing 1.0 ml of EO solution at 50 microg/ml and 0.5 g of the milky lotion into a 10-ml volumetric flask, the methanol was added to make until that volume. The suspending mixture was moved to a centrifuging tube with a cap. After centrifuging at 3000 rpm for 5 minutes, the supernatant was used as the testing solution. The testing solution of 20 microl was determined by HPLC using the ODS column (CAPCELL PAK C18 column, 4.6 x 250 mm), the mixture of water and acetonitrile (31:9) and the detection wavelength of 285 nm. The working curve from 1.0 to 6.0 microg/ml showed a linear line between the concentrations of EO and the peak area. There was no interference of peak of EO from the lotion and milky lotion.
    Kokuritsu Iyakuhin Shokuhin Eisei Kenkyūjo hōkoku = Bulletin of National Institute of Health Sciences 02/2004;
  • Journal of Health Science - J HEALTH SCI. 01/2004; 50(1):101-107.
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    ABSTRACT: Inorganic arsenic is an environmental contaminant and is associated with the increased risk of human skin cancer. Arsenic has been reported to activate or inhibit a variety of cellular signalling pathways which has effects on cell growth, differentiation and apoptosis. However, the molecular mechanisms of these arsenic-induced biological effects are not completely understood. To understand the molecular basis for the mode of action of arsenicals, we examined the effect of arsenite and arsenate on the activation of mitogen-activated protein kinases (MAPK) and the upstream signalling cascade in normal human epidermal keratinocytes (NHEK). NHEK were exposed to arsenite or arsenate. Western blot analysis was performed to determine the activation of extracellular signal-regulated kinases (ERK) 1/2, c-jun N-terminal kinases (JNK), p38, and MAPK or ERK kinases (MEK) 1/2. Epidermal growth factor receptor (EGFR) tyrosine phosphorylation and recruitment of its adaptor proteins, Shc and Grb2, to EGFR were detected by immunoprecipitation and Western blot analysis. Both arsenicals activated ERK1/2, which are most highly activated in response to mitogenic stimulation, in addition to JNK and p38, which show greater activation in response to cellular stresses. The kinetics of ERK1/2 activation differed from those of JNK and p38 activation. Both arsenicals transiently activated ERK1/2 prior to JNK and p38 activation. MEK1/2, upstream kinases of ERK1/2, were also activated by arsenicals with similar time kinetics to that of ERK1/2 activation. To investigate a signalling pathway leading to activation of MEK1/2-ERK1/2, we examined the tyrosine phosphorylation of EGFR and Shc adapter protein. Both arsenicals stimulated tyrosine phosphorylation of EGFR and Shc. After arsenical treatment, Shc immunoprecipitates contained coprecipitated EGFR and Grb2, suggesting that both arsenicals induce the assembly of EGFR-Shc-Grb2 complexes. Both the EGFR inhibitor tyrphostin AG1478 and anti-EGFR blocking antibody markedly attenuated ERK1/2 activation induced by arsenicals, but did not affect JNK and p38 activation. Our data indicate that both arsenite and arsenate activate the EGFR-Shc-Grb2-MEK1/2-ERK1/2 signalling cascade in NHEK.
    British Journal of Dermatology 01/2004; 149(6):1116-27. · 3.76 Impact Factor

Publication Stats

2k Citations
225.38 Total Impact Points


  • 2006–2008
    • Musashino University
      Edo, Tōkyō, Japan
  • 2004–2006
    • Chiba University
      • Faculty of Engineering
      Chiba-shi, Chiba-ken, Japan
  • 1994–2004
    • National Institute of Health Sciences, Japan
      • • Division of Environmental Chemistry
      • • Project Team for Pharmacogenetics
      Edo, Tōkyō, Japan
  • 2000
    • Fukuoka Institute of Health and Environmental Sciences
      Hukuoka, Fukuoka, Japan
    • Jadavpur University
      • School of Environmental Studies
      Calcutta, Bengal, India
  • 1997
    • Kyoritsu College of Pharmacy
      Tōkyō, Japan