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13. Simultaneous bidirectional transceiver logic

Author

Ishibashi, K., primary, Goto, T., additional, Hayashi, T., additional, Okada, T., additional, Yamagiwa, A., additional, Shibata, M., additional, Akimoto, M., additional, Akimoto, K., additional, Hamanaka, N., additional, Takahashi, T., additional, Koyama, A., additional, and Aida, T., additional

Published
1999
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23. Diastereoselective Synthesis of ψ[(E)-CMe&dbd;CH]- and ψ[(E)-CMe&dbd;CMe]- Type Dipeptide Isosteres Based on Organocopper-Mediated anti-S<INF>N</INF>2‘ Reaction

Author

Oishi, S., Niida, A., Kamano, T., Odagaki, Y., Tamamura, H., Otaka, A., Hamanaka, N., and Fujii, N.

Abstract

A straightforward synthetic route for the synthesis of diastereomerically pure ψ[(E)-CMe&dbd;CH]- and ψ[(E)-CMe&dbd;CMe]-type dipeptide isosteres was developed on the basis of regio- and stereoselective anti-SN2‘ alkylation of 3-(N-Boc-5-methyl-4-substituted-oxazolidin-2-on-5-yl)acrylates with organocopper reagents.

Published
2002
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24. Diastereoselective Synthesis of ψ[(E)-CH&dbd;CMe]- and ψ[(Z)-CH&dbd;CMe]-Type Dipeptide Isosteres by Organocopper-Mediated anti-S<INF>N</INF>2‘ Reaction

Author

Oishi, S., Kamano, T., Niida, A., Odagaki, Y., Tamamura, H., Otaka, A., Hamanaka, N., and Fujii, N.

Abstract

Acyclic ψ[(E)-CH&dbd;CMe]- and ψ[(Z)-CH&dbd;CMe]-type dipeptide isosteres were efficiently synthesized. In a key reaction, α-alkylation of γ-mesyloxy-β-methyl-α,β-unsaturated esters with organocyanocuprates in diethyl ether or tetrahydrofuran preferentially afforded the ψ[(E)-CH&dbd;CMe]- or ψ[(Z)-CH&dbd;CMe]-isomer, respectively, via anti-SN2‘ mechanism.

Published
2002
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25. Effect of Membrane Constitution on the Direction of Ionic Transport Across Bipolar Membranes

Author

Higa, M., Tsukamoto, Y., Hamanaka, N., and Matsusaki, K.

Abstract

Countertransport of ions is defined as the transport of an ion against its own concentration gradient driven by the third driving electrolyte added to the systems. The simulations and the experiments presented show that in the systems that consist of NaCl, KCl, and CaCl2 solutions divided by a bipolar membrane, there are two types of the countertransport of K+ and Ca2+ ions: forward countertransport (the countertransport in the direction of the concentration gradient of the driving electrolyte, NaCl) and backward countertransport (the countertransport in the direction opposite to the concentration gradient). In the system where the negatively charged layer of the membrane contacts the solution at the high-concentration side of NaCl, the forward countertransport occurs, and the membrane has permselectivity for univalent ions. In the system where the positively charged layer contacts the solution at the high-concentration side, the mode of the countertransport depends on the charge density ratio of the two charged layers.

Published
2000

28. 7-[(1R,2S,3S,5R)-6,6-dimethyl-3-(4- iodobenzenesulfonylamino)bicyclo[3.1.1]hept-2-yl]-5(Z)-heptenoic acid: a novel high-affinity radiolabeled antagonist for platelet thromboxane A2/prostaglandin H2 receptors.

Author

Naka, M, Mais, D E, Morinelli, T A, Hamanaka, N, Oatis, J E, and Halushka, P V

Abstract

A high-affinity thromboxane (TX)A2/prostaglandin (PG) H2 receptor antagonist, I-SAP [7-[(1R,2S,3S,5R)-6,6-dimethyl-3-(4- iodobenzenesulfonylamino)bicyclo[3.1.1]hept-2-yl]-5(Z)-heptenoic acid] and its radiolabeled analog [125I]SAP (Mais et al., 1991) are characterized in the present study. I-SAP antagonized I-BOP ([1S-(1 alpha, 2 beta(5Z),3 alpha(1E,3R*),4 alpha)]-7-[3-(3-hydroxy-4- (4'-iodophenoxy)-1-butenyl)-7-oxabicyclo-[2.2.1]heptan-2y l]-5'heptenoic acid) and U46619 [15S-hydroxy-11 alpha,9 alpha-(epoxymethano)-prosta-5Z,13E-dienoic acid)], two different TXA2/PGH2 mimetics, induced aggregation of washed human platelets in a similar manner (pA2 of 8.11 +/- 0.09, Kd = 7.8 nM, n = 3; pA2 = 8.01 +/- 0.05, Kd = 9.7 nM, n = 8, respectively). I-SAP also had agonistic activity, producing platelet shape change (EC50 = 9.7 nM +/- 0.6 nM at pH 7.4, n = 3) which was blocked by pretreatment of platelets with SQ29548 ([1S-(1 alpha,2 beta(5Z),3 beta,4 alpha)]-7-[3-[[2- [(phenylamino)carbonyl]hydrazino]methyl]-7-oxabicyclo[2.2.1]hept- 2-yl]-5-heptenoic acid), a TXA2/PGH2 receptor antagonist. Radioligand binding studies were performed with [125I]SAP using washed human platelets. Competition of three agonists and four antagonists for binding with [125I]SAP was determined. The compounds showed the appropriate rank order potencies, including stereoselective competition by a pair of stereoisomeric antagonists. In washed human platelets, the Kd for I-SAP was 468 +/- 49 pM and the maximum binding (Bmax) was 2057 +/- 156 sites/platelet at pH 7.4 (n = 6). The Bmax was significantly increased 49% to 3072 +/- 205 sites/platelet at pH 6.5 (P less than .01 but the Kd was unchanged (490 +/- 18 pM, n = 6).(ABSTRACT TRUNCATED AT 250 WORDS)

Published
1992

29. Pharmacologic characterization of human and canine thromboxane A2/prostaglandin H2 receptors in platelets and blood vessels: evidence for different receptors.

Author

Mais, D E, Saussy, D L, Chaikhouni, A, Kochel, P J, Knapp, D R, Hamanaka, N, and Halushka, P V

Abstract

The present study was undertaken to characterize thromboxane A2/prostaglandin H2 (TXA2/PGH2) receptors in platelets and blood vessels. Both human and canine platelet aggregation and saphenous vein contractions were induced by the stable TXA2/PGH2 mimetics (15S)-hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5Z, 13E-dienoic acid (U46619) and 9,11-epithio-11,12-methano-TXA2 (ONO-11113). ONO-11113 was a more potent agonist than U46619 in the human saphenous vein but less potent in the platelet. These agonists were equipotent in the canine platelet but ONO-11113 was more potent in the saphenous vein. Platelet aggregation and saphenous vein contraction induced by U46619 were blocked in a dose-dependent manner by the TXA2/PGH2 receptor agonists 9,11-dimethylmethano-11,12-methano-16-phenyl-13,14-dehydro-13-aza- 15 alpha beta-omega-tetranor-TXA2 (ONO-11120), 9,11-dimethylmethano-11,12-methano-16-(4-hydroxyphenyl)-13,14-d ihy dro-13-aza-15 alpha beta-omega-tetranor-TXA2 (PTA-OH), 9,11-dimethylmethano-11,12-methano-16-(4-methoxyphenyl)-13,14-d ihy dro-13-aza-15 alpha beta-omega-tetranor-TXA2 (PTA-OM), 9,11-dimethylmethano-11,12-methano-16-(3-iodo-4-hydroxyphenyl-13,1 4-dihydro-13- aza-15 alpha beta-omega-tetranor-TXA2 (I-PTA-OH) and 9,11-dimethylmethano-11,12-methano-15-phenyl-13,14-dihydro-13-aza- 15 alpha beta-omega-pentanor-TXA2 [PTA-(omega-1)].(ABSTRACT TRUNCATED AT 250 WORDS)

Published
1985

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