101
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Yoshimura N, Kudoh S, Mukohara T, Yamauchi S, Yamada M, Kawaguchi T, Nakaoka Y, Hirata K, Yoshikawa J. Phase I/II study of cisplatin combined with weekly paclitaxel in patients with advanced non-small-cell lung cancer. Br J Cancer 2004; 90:1184-9. [PMID: 15026799 PMCID: PMC2409643 DOI: 10.1038/sj.bjc.6601672] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
To determine the maximum-tolerated dose (MTD) and the recommended dose (RD) of paclitaxel administered weekly with a fixed dose of cisplatin, and to assess the toxicity and activity of this combination, we conducted a phase I/II trial in patients with advanced non-small-cell lung cancer (NSCLC). In this study, patients with stage IIIB/IV NSCLC were eligible. Paclitaxel, at a starting dose of 40 mg m−2 week−1 on days 1, 8, and 15, was combined with a fixed dose of cisplatin 80 mg m−2 on day 1. Chemotherapy was given in a 4-week cycle. In this phase I/II study, 38 patients were enrolled. Dose-limiting toxicities (DLT) were neutropenia, fatigue, and omission of treatment due to leucopenia, thrombocytopenia, or febrile neutropenia. The MTD and RD were estimated to be 70 mg m−2. Of the 37 assessable patients, 23 had a partial response and one had a complete response. Overall response rate was 62.1% (95% confidence interval (CI): 46.5–77.7%). The progression-free survival, the median survival time, and the 1-year survival rate were 5.5 months, 13.7 months, and 56.9%, respectively. This regimen is tolerable and very active against advanced NSCLC, and its efficacy should be confirmed in a phase III study.
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102
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Machida M, Shono E, Kimura M, Yamauchi S. Electrochemical lean-deNO catalyst using H+-conducting solid polymer electrolyte. CATAL COMMUN 2003. [DOI: 10.1016/j.catcom.2003.10.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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103
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Yamauchi S, Kinoshita Y, Kinoshita Y. New method for synthesizing the intermediates to 5-HETE from yeast-mediated reduction products by employing Baeyer-Villiger oxidation with complete retention of enantiomeric excess. Biosci Biotechnol Biochem 2003; 67:1959-69. [PMID: 14519982 DOI: 10.1271/bbb.67.1959] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
(R) and (S)-Aldehydes 2, which are intermediates for the synthesis of (5R) and (5S)-HETE, were respectively synthesized from the yeast-mediated reductive products, hydroxy ester 3 and cis-lactone 4, through Baeyer-Villiger oxidation with complete retention of enantiomeric excess.
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104
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Yamauchi S, Takeishi Y, Minamihaba O, Arimoto T, Hirono O, Takahashi H, Miyamoto T, Nitobe J, Nozaki N, Tachibana H, Watanabe T, Fukui A, Kubota I. Angiotensin-converting enzyme inhibition improves cardiac fatty acid metabolism in patients with congestive heart failure. Nucl Med Commun 2003; 24:901-6. [PMID: 12869823 DOI: 10.1097/01.mnm.0000084579.51410.69] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
This study aimed to examine whether angiotensin-converting enzyme (ACE) inhibition improved cardiac fatty acid metabolism in patients with congestive heart failure (CHF). Myocardial 123I-beta-methyl-iodophenylpentadecanoic acid (123I-BMIPP) imaging was performed in 25 patients with CHF and in 10 control subjects. Myocardial 123I-BMIPP images were obtained 30 min and 4 h after tracer injection. The heart-to-mediastinum (H/M) ratio of 123I-BMIPP uptake and the washout rate of 123I-BMIPP from the myocardium were calculated. Patients were given enalapril for 6 months, and 123I-BMIPP imaging was repeated. H/M ratios on early and delayed images were lower in CHF patients than in normal controls (P<0.01). The washout rate of 123I-BMIPP from the myocardium was faster in CHF patients than in controls (P<0.01). As the severity of the New York Heart Association (NYHA) functional class increased, the H/M ratio decreased and the washout rate increased. The washout rate of 123I-BMIPP was inversely correlated with left ventricular fractional shortening (R=-0.62, P<0.01). ACE inhibition with enalapril increased the H/M ratio on delayed images (P<0.05) and reduced the washout rate of 123I-BMIPP (P<0.05) in CHF patients. These data suggest that: (1) angiotensin II-mediated intracellular signalling activation may be a possible mechanism for the decreased myocardial uptake and enhanced washout of 123I-BMIPP in heart failure patients; and (2) the improvement in fatty acid metabolism by ACE inhibition may represent a new mechanism for the beneficial effect of this therapy in heart failure.
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Abstract
Morinol C and morinol D are neolignans isolated from the Chinese medicinal herb Morina chinensis as racemates. (1R,2R)-Morinol C and (1S,2R)-morinol D were synthesized from (+)-(3R,4R)-4-(3,4-dimethoxyphenyl)-3-pivaloyloxymethyl-4-butanolide 4. On the other hand, (1S,2S)-morinol C and (1R,2S)-morinol D were synthesized from anti-aldol product 8.
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106
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Yamauchi S, Yamaguchi M. Synthesis of (+)-aptosimon, a 4-oxofurofuran lignan, by erythro selective aldol condensation and stereoconvergent cyclization as the key reactions. Biosci Biotechnol Biochem 2003; 67:838-46. [PMID: 12784626 DOI: 10.1271/bbb.67.838] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The 4-oxofurofuran lignan, (+)-aptosimon (1), was synthesized from gamma-butyrolactone (9). To construct the two benzylic chiral center of (+)-aptosimon (1), highly erythro selective aldol condensation and stereoconvergent SN1 intramolecular cyclization were used as the key reactions.
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107
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Minamihaba O, Takeishi Y, Hirono O, Yamauchi S, Arimoto T, Fukui A, Okuyama M, Nozaki N, Akiyama H, Fatema K, Miyamoto T, Takahashi H, Fujiwara S, Okada A, Takahashi K, Kubota I. Pulsed Doppler tissue imaging for the assessment of myocardial viability: comparison with 99mTc sestamibi perfusion imaging. Nucl Med Commun 2002; 23:1197-204. [PMID: 12464785 DOI: 10.1097/00006231-200212000-00008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The aim of the present study was to examine whether Doppler tissue imaging demonstrated comparable diagnostic performance for the detection of viable myocardium compared to myocardial perfusion imaging with Tc hexakis-2-methoxyisobutylisonitrile (MIBI). We studied 30 patients with old myocardial infarction who underwent percutaneous transluminal coronary angioplasty (PTCA). Myocardial single photon emission computed tomography (SPECT) with Tc-MIBI and two-dimensional echocardiography were carried out within 7 days before PTCA. We measured regional Tc-MIBI uptake for each myocardial segment from SPECT and peak systolic velocity and a ratio of regional pre-ejection period to regional ejection time (PEP/ET) from pulsed Doppler tissue imaging. Biplane left ventriculography was performed before interventional procedures and repeated 3 months after PTCA. Myocardial viability was determined when wall motion was improved at least one grade after PTCA. The peak systolic velocity was positively correlated with regional Tc-MIBI uptake (R =0.59, P<0.01). The PEP/ET demonstrated inverse correlation with Tc-MIBI uptake ( R=-0.59, P<0.01). Peak systolic velocity of viable segments was higher than that of non-viable segments ( P<0.05). The PEP/ET was lower in viable segments than in non-viable segments ( P<0.05). Peak systolic velocity and PEP/ET demonstrated high diagnostic accuracy for detecting viable myocardium compared with Tc-MIBI perfusion imaging (80% and 79% vs 90%). These data indicate that measurements of regional peak systolic velocity and PEP/ET by Doppler tissue imaging are useful for evaluating myocardial viability quantitatively and provide helpful information for a clinical judgment in an interventional strategy.
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108
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Matsui F, Kawashima S, Shuo T, Yamauchi S, Tokita Y, Aono S, Keino H, Oohira A. Transient expression of juvenile-type neurocan by reactive astrocytes in adult rat brains injured by kainate-induced seizures as well as surgical incision. Neuroscience 2002; 112:773-81. [PMID: 12088737 DOI: 10.1016/s0306-4522(02)00136-7] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Neurocan is one of the major chondroitin sulfate proteoglycans expressed in nervous tissues. The expression of neurocan is developmentally regulated, and full-length neurocan is detected in juvenile brains but not in adult brains. In the present study, we demonstrated by western blot analysis that full-length neurocan transiently appeared in adult rat hippocampus when it was lesioned by kainate-induced seizures. Immunohistochemical studies showed that neurocan was detected mainly around the CA1 region although the seizure resulted in neuronal cell degeneration in both the CA1 and CA3 regions of the hippocampus. Double-labeling for neurocan mRNA and glial fibrillary acidic protein demonstrated that many reactive astrocytes expressed neurocan mRNA. The re-expression of full-length neurocan was also observed in the surgically injured adult rat brain. In contrast, the expression of other nervous tissue chondroitin sulfate proteoglycans, such as phosphacan and neuroglycan C, was not intensified but rather was either reduced in the kainate-lesioned hippocampus or in the surgically injured cerebral cortex. These observations indicate that induction of neurocan expression by reactive astrocytes is a common phenomenon in the repair process of adult brain injury, and therefore, it can be postulated that juvenile-type neurocan plays some roles in brain repair.
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109
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Yamauchi S, Bando S, Kinoshita Y. Synthesis of 1,2-oxygenated 6-arylfurofuran lignan: stereoselective synthesis of (1S,2S,5R,6S)-1-hydroxysamin. Biosci Biotechnol Biochem 2002; 66:1495-9. [PMID: 12224633 DOI: 10.1271/bbb.66.1495] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
(1S,2S,5R,6S)-6-(3,4-Methylenedioxyphenyl)-3,7-dioxabicyclo[3.3.0]octan-1,2-diol ((+)-1-hydroxysamin 1) was synthesized, starting from olefin 8. Stereoselective alpha-hydroxylation was achieved after converting 8 to aldehyde 13. Resulting unstable alpha-hydroxy aldehyde 14 was then transformed to (+)-1-hydroxysamin (1). This is a new efficient synthetic route to 1,2-oxygenated 6-arylfurofuran lignans.
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Fujiwara S, Takeishi Y, Hirono O, Fukui A, Okuyama M, Yamaguchi S, Ito M, Kaneko K, Shishido T, Miyamoto T, Yuki K, Miyashita T, Takahashi K, Minamihaba O, Tomoike H, Yamauchi S, Fatema K. Reverse redistribution of 99m Tc-sestamibi after direct percutaneous transluminal coronary angioplasty in acute myocardial infarction: relationship with wall motion and functional response to dobutamine stimulation. Nucl Med Commun 2001; 22:1223-30. [PMID: 11606888 DOI: 10.1097/00006231-200111000-00009] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Reverse redistribution (RR) of 99mTc-sestamibi is observed after direct percutaneous transluminal coronary angioplasty (PTCA) in acute myocardial infarction (AMI). The purpose of this study was to clarify the functional characteristics of myocardial segments with RR after direct PTCA in AMI. Thirty patients with AMI who had undergone direct PTCA were examined. Myocardial perfusion tomography with 99mTc-sestamibi and low dose dobutamine echocardiography were performed within 2 weeks of the onset. The 99mTc-sestamibi images were obtained 1 and 3 h after tracer administration. The left ventricle was divided into nine segments, and regional 99mTc-sestamibi uptake and clearance were quantitatively evaluated in each segment. RR was defined as a decrease in 99mTc-sestamibi uptake of >10% on 3 h delayed images compared with the 1 h early images. The left ventricle in the echocardiographic images was also divided into nine segments corresponding to the scintigraphic images, and regional wall motion was assessed in the resting condition as the baseline and during dobutamine administration (5-10 microg x kg(-1) x min(-1)). Out of a total of 270 myocardial segments, 111 segments were perfused by the culprit coronary artery and were defined as ischaemic segments. There were 25 segments with RR and 86 segments without RR in the ischaemic myocardium. Enhanced clearance of 99mTc-sestamibi was observed in ischaemic segments with RR (P<0.001). Echocardiography demonstrated that 24 out of 25 segments with RR and 61 out of 86 segments without RR had wall motion abnormalities. Dobutamine infusion improved wall motion in 20 (83%) of the 24 dysfunctional segments with RR and 33 (54%) of the 61 dysfunctional segments without RR (P<0.02). These findings suggest that RR indicates reversible functional abnormalities associated with preserved contractile reserve in response to dobutamine. The early and delayed imaging of 99mTc-sestamibi provides useful information regarding the residual viability of the dysfunctional myocardium in AMI patients.
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111
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Ebisawa K, Maeda Y, Kaneda H, Yamauchi S. Origin of the hard x-ray emission from the Galactic plane. Science 2001; 293:1633-5. [PMID: 11498545 DOI: 10.1126/science.1063529] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The Galactic plane is a strong emitter of hard x-rays (2 to 10 kiloelectron volts), and the emission forms a narrow continuous ridge. The currently known hard x-ray sources are far too few to explain the ridge x-ray emission, and the fundamental question of whether the ridge emission is ultimately resolved into numerous dimmer discrete sources or truly diffuse emission has not yet been settled. In order to obtain a decisive answer, using the Chandra X-ray Observatory, we carried out the deepest hard x-ray survey of a Galactic plane region that is devoid of known x-ray point sources. We detected at least 36 new hard x-ray point sources in addition to strong diffuse emission within a 17' by 17' field of view. The surface density of the point sources is comparable to that at high Galactic latitudes after the effects of Galactic absorption are considered. Therefore, most of these point sources are probably extragalactic, presumably active galaxies seen through the Galactic disk. The Galactic ridge hard x-ray emission is diffuse, which indicates omnipresence within the Galactic plane of a hot plasma, the energy density of which is more than one order of magnitude higher than any other substance in the interstellar space.
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112
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Miyagi Y, Yamauchi S, Suzuki S, Kitagawa A, Masaki Y, Gomibuchi M, Tanaka S. Investigation of coronary artery bypass grafting for a patient with myelodysplastic syndrome. Ann Thorac Cardiovasc Surg 2001; 7:250-3. [PMID: 11578269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023] Open
Abstract
A 79-year-old male with unstable angina, who had myelodysplastic syndrome (MDS), was treated with coronary artery bypass grafting (CABG). MDS causes refractory anemia accompanied by various degrees of granulocytopenia and thrombocytopenia. Pancytopenia caused by MDS may complicate patients with major infections and bleeding during cardiac surgery. There were very few patients with MDS who had undergone open-heart surgery. Three case studies, including this study, had reported successful cases of CABG in patients with MDS and the analogous diseases of MDS. We used granulocyte colony-stimulating factor (G-CSF), red blood cells (RBCs) and platelets transfusions in peri-operative state. We did not need a large amount of transfusion of RBCs and platelets in intra-operative and postoperative states. We had prevented major bleeding and severe wound infections in the acute postoperative state.
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113
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Yamauchi S, Kinoshita Y. Synthesis of cis-lactone lignan, cis-(2S,3R)-parabenzlactone, from L-arabinose. Biosci Biotechnol Biochem 2001; 65:1669-72. [PMID: 11515556 DOI: 10.1271/bbb.65.1669] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
As a model synthesis on cis-2,3-dibenzyl-4-butanolide lignan, cis-(2S,3R)-parabenzlactone bearing a chiral benzyl alcohol moiety was stereoselectively synthesized from L-arabinose.
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114
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Yamauchi S, Kinoshita Y. First stereoselective synthesis of (+)-magnostellin C, a tetrahydrofuran type of lignan bearing a chiral secondary benzyl alcohol. Biosci Biotechnol Biochem 2001; 65:1559-67. [PMID: 11515539 DOI: 10.1271/bbb.65.1559] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
(+)-Magnostellin C, which is a tetrahydrofuran type of lignan bearing a chiral secondary benzylic hydroxy group, was stereoselectively synthesized from L-arabinose by using threo selective aldol condensation.
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115
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Kimura T, Kudoh S, Yamauchi S, Yoshimura N, Mukohara T, Hirata K, Kawahara M, Yoshikawa J. In vitro schedule dependency in the formation of topoisomerase I and II inhibitor and DNA cleavable complexes. Eur J Cancer 2001. [DOI: 10.1016/s0959-8049(01)80645-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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116
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Yamauchi S, Kudoh S, Kimura T, Yosimura N, Mukohara T, Hirata K, Yoshikawa J. Combination effects of amrubicin, a novel anthracycline, with cisplatin on human lung cancer cells. Eur J Cancer 2001. [DOI: 10.1016/s0959-8049(01)80651-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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117
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Yamauchi S, Tanaka T, Kinoshita Y. First highly stereoselective synthesis of (+)-dihydrosesamin, a trisubstituted tetrahydrofuran-type of lignan, by using highly erythro-selective aldol condensation. ACTA ACUST UNITED AC 2001. [DOI: 10.1039/b105419h] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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118
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Okuda T, Mita S, Yamauchi S, Fukuta M, Nakano H, Sawada T, Habuchi O. Molecular cloning and characterization of GalNAc 4-sulfotransferase expressed in human pituitary gland. J Biol Chem 2000; 275:40605-13. [PMID: 11001942 DOI: 10.1074/jbc.m007983200] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have previously cloned chondroitin-4-sulfotransferase (C4ST) cDNA from mouse brain. In this paper, we report cloning and characterization of GalNAc 4-sulfotransferase (GalNAc4ST), which transfers sulfate to position 4 of the nonreducing terminal GalNAc residue. The obtained cDNA contains a single open reading frame that predicts a type II transmembrane protein composed of 424 amino acid residues. Identity of the amino acid sequence between GalNAc4ST and human C4ST was 30%. When the cDNA was transfected in COS-7 cells, sulfotransferase activity toward carbonic anhydrase VI was overexpressed but no sulfotransferase activity toward chondroitin or desulfated dermatan sulfate was increased over the control. Sulfation of carbonic anhydrase VI by the recombinant GalNAc4ST occurred at position 4 of the GalNAc residue of N-linked oligosaccharides. The recombinant GalNAc4ST transferred sulfate to position 4 of GalNAc residue of p-nitrophenyl GalNAc, indicating that this sulfotransferase transfers sulfate to position 4 at the nonreducing terminal GalNAc residue. Dot blot analysis showed that the message of GalNAc4ST was expressed strongly in the human pituitary, suggesting that the cloned GalNAc4ST may be involved in the synthesis of the nonreducing terminal GalNAc 4-sulfate residues found in the N-linked oligosaccharides of pituitary glycoprotein hormones.
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119
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Okuda T, Mita S, Yamauchi S, Matsubara T, Yagi F, Yamamori D, Fukuta M, Kuroiwa A, Matsuda Y, Habuchi O. Molecular cloning, expression, and chromosomal mapping of human chondroitin 4-sulfotransferase, whose expression pattern in human tissues is different from that of chondroitin 6-sulfotransferase. J Biochem 2000; 128:763-70. [PMID: 11056388 DOI: 10.1093/oxfordjournals.jbchem.a022813] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Chondroitin 4-sulfotransferase (C4ST) catalyzes the transfer of sulfate from 3'-phosphoadenosine 5'-phosphosulfate to position 4 of the N-acetylgalactosamine residues of chondroitin. We previously reported the cloning of C4ST cDNA from mouse brain. We here report the cloning and expression of human C4ST cDNA. The cDNA was isolated from a human fetal brain cDNA library by hybridization with a DNA probe prepared from rat poly(A)(+) RNA used for the cloning of mouse C4ST cDNA. The cDNA comprises a single open reading frame that predicts a Type II transmembrane protein composed of 352 amino acids. The protein has an amino acid sequence homology of 96% with mouse C4ST. When the cDNA was introduced into a eukaryotic expression vector and transfected in COS-7 cells, the sulfotransferase activity that transfers sulfate to both chondroitin and desulfated dermatan sulfate was overexpressed. Northern blot analysis indicated that human C4ST mRNAs (6.0 and 1.9 kb) are expressed ubiquitously in various adult human tissues. Dot blot analysis has shown that human C4ST is strongly expressed in colorectal adenocarcinoma and peripheral blood leukocytes, whereas strong expression of human chondroitin 6-sulfotransferase (C6ST) is observed in aorta and testis. These observations suggest that the expression of C4ST and C6ST may be controlled differently in human tissues. The C4ST gene was localized to chromosome 12q23.2-q23.3 by fluorescence in situ hybridization.
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120
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Yamauchi S, Kinoshita Y. Synthesis of optically active olivil type of lignan from L-arabinose using threo-selective aldol condensation as a key reaction. Biosci Biotechnol Biochem 2000; 64:2320-7. [PMID: 11193398 DOI: 10.1271/bbb.64.2320] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The threo-selective aldol condensation of (3R, 4S)-3-hydroxy-5-trityloxy-4-pentanolide, which was prepared from L-arabinose, with piperonal was applied to the stereoselective synthesis of the olivil type of lignan, (2R, 3R, 4R)-4-benzyl-4-hydroxy-3-hydroxymethyl-2-(3,4-methylenedioxyphenyl)tetrahydrofuran.
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121
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Yamauchi S, Yamamoto N, Kinoshita Y. Improved stereoselective synthesis of optically active methylene lactone, key intermediate for the synthesis of 1,2-oxidized furofuran lignan, by direct alpha-methylenation to butanolide. Biosci Biotechnol Biochem 2000; 64:2209-15. [PMID: 11129596 DOI: 10.1271/bbb.64.2209] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
(3R)-3-[(1R)-1-(tert-Butyldimethylsilyl)oxy-1-(2-methoxy-4,5-methylenedioxyphenyl) methyl]-2-methylene-4-butanolide, which is a key intermediate for the synthesis of 1,2-oxidized furofuran lignan, was stereoselectively synthesized from L-glutamic acid by applying direct methylenation to butanolide.
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Nakamura M, Nakajima T, Ohba Y, Yamauchi S, Lee BR, Ichishima E. Identification of copper ligands in Aspergillus oryzae tyrosinase by site-directed mutagenesis. Biochem J 2000; 350 Pt 2:537-45. [PMID: 10947969 PMCID: PMC1221282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
Copper ligands of the recombinant tyrosinase from the fungus Aspergillus oryzae expressed in Saccharomyces cerevisiae or Escherichia coli were identified by site-directed mutagenesis. The recombinant protyrosinases expressed in S. cerevisiae were assayed for catalytic activities of mono-oxygenase and L-dopa oxidase at pH 5.5 after acid shock at pH 3.0. Replacements of His-63, His-84, His-93, His-290, His-294, His-332 or His-333 with asparagine resulted in mutant enzymes exhibiting no activities. The site-directed mutant Cys82Ala showed that Cys-82 was also an essential residue for the activity. We obtained homogeneous preparations of activated tyrosinases from mutated thioredoxin fusion gene products expressed in E. coli by acid shock. The copper contents of engineered mutants and wild-type enzyme expressed in E. coli were determined by atomic absorption spectrophotometry. The wild-type enzyme contained 2 g-atoms of copper/mol of the subunit. The His63Asn, His84Asn, His93Asn, His290Asn, His294Asn, His332Asn, His333Asn or Cys82Ala substitution decreased copper binding by approx. 50%, indicating that the mutants contain only approx. 1 g-atom of copper/mol of the subunit. The five mutants His63Asn, His93Asn, His290Asn, His294Asn and Cys82Ala contain only one copper ion, which is fully detectable by EPR. From the correlation of g( parallel) and (Cu)A( parallel), we deduced that the nitrogen or sulphur donors in the copper ligands should be in a square or a distorted tetrahedral geometric environment. In further atomic absorption spectrophotometry experiments, no copper atom was observed in the seven double mutants His63Asn/His290Asn, His63Asn/His294Asn, His63Asn/His332Asn, His63Asn/His333Asn, Cys82Ala/His290Asn, His84Asn/His333Asn and His93Asn/His290Asn. We propose a new structure of active sites of tyrosinase from A. oryzae: the most likely binding sites of tyrosinase for Cu(A) are His-63, His-84 and His-93, with the remaining conserved Cys-82 providing the fourth ligand. Cu(B) liganded by four histidine residues, His-290, His-294, His-332 and His-333, is identified as new binding motif of Cu(B).
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Watanabe T, Yamaki M, Tachibana H, Yamauchi S, Kubota I, Tomoike H. Anisotropic effects of sodium channel blockers on the wavelength for ventricular excitation in dogs. JAPANESE CIRCULATION JOURNAL 2000; 64:689-94. [PMID: 10981854 DOI: 10.1253/jcj.64.689] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The purpose of this study was to determine the anisotropic effects of sodium channel blockers on wavelength (WL) and proarrhythmia. In 18 anesthetized, open chest dogs, a 64-electrode array was placed on the left ventricle and the ventricle was constantly paced. Disopyramide, lidocaine or flecainide was intracoronarily administered. Conduction velocity (theta) and activation-recovery interval (ARI) were measured in the longitudinal (L) and transverse (T) directions. Flecainide markedly decreased thetaL, but did not alter thetaT or ARIs in either direction. As a result, the wavelength was significantly shortened only in the L direction. Disopyramide or lidocaine did not show direction-dependent effects on theta or WL. In 3 of 6 dogs with flecainide exposure, ventricular fibrillation (VF) developed. However, no VF occurred with disopyramide or lidocaine. Accordingly, the WL is dependent on the fiber orientation of myocardium. The anisotropic shortening of the WL may explain the character of the proarrhythmia observed with flecainide.
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Yamauchi S, Kinoshita Y. Stereoselective model synthesis of the optically active olivil type of lignan from D-xylose. Biosci Biotechnol Biochem 2000; 64:1563-71. [PMID: 10993140 DOI: 10.1271/bbb.64.1563] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The olivil type of lignan, (2S,3R,4R)-4-benzyl-4-hydroxy - 3 - hydroxymethyl - 2 - (3,4 - methylenedioxyphenyl)tetrahydrofuran, was stereoselectively synthesized from D-xylose.
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Miyashita T, Kubota I, Yamaki M, Watanabe T, Yamauchi S, Tomoike H. 4-aminopyridine inhibits the occurrence of ventricular fibrillation but not ventricular tachycardia in the reperfused, P6olated rat heart. JAPANESE CIRCULATION JOURNAL 2000; 64:602-5. [PMID: 10952157 DOI: 10.1253/jcj.64.602] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The 4-aminopyridine (4-AP)-sensitive transient outward current (Ito) has been reported to play an important role in the ischemia- or high [Ca2+]o-induced reentrant ventricular arrhythmias. However, the role of 4-AP sensitive Ito in reperfusion arrhythmia remains unknown. Rat hearts were perfused with Tyrode solution (control), and treated with 0.5 micromol/L verapamil, 1 micromol/L glibenclamide, 10 micromol/L E-4031 or 2 mmol/L 4-AP. After a 10-min perfusion, hearts were subjected to 30-min global ischemia followed by 10-min reperfusion. The effects of the ion-channel blockers on the incidence of ventricular tachycardia (VT), torsades de pointes (Tdp) and ventricular fibrillation (VF) during the reperfusion period were investigated. Verapamil and 4-AP abolished VF and Tdp. The incidence of VT was also attenuated by verapamil, but not by 4-AP. Glibenclamide and E-4031 (a blocker of a rapidly activating component of delayed rectifier K+ current) did not affect the incidence of those tachyarrhythmias. Accordingly, (1) the underlying mechanism of VF or Tdp is different from that of VT, and (2) 4-AP sensitive Ito is required for the occurrence of reperfusion Tdp or VF in the present model.
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