Publications by authors named "A Hazato"

While searching for vitamin D(3) analogues which inhibit neutrophil recruitment in the lung without elevating plasma calcium level, we found that (5Z,7E)-(1S,3R)-20(R)-[(5E)-(2S)-2-hydroxy-2-methyl-cyclopentanone-5-ylidene]methyl-9,10-secopregna-5,7,10(19)-triene-1,3-diol (TEI-A00114) had the best efficacy and calcemic action. TEI-A00114 has a vitamin D receptor affinity 2.5-fold weaker and a vitamin D binding protein affinity 330.

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13,14-Dihydro-15-deoxy-Delta7-prostaglandin A1 methyl ester (TEI-9826), an antitumor prostaglandin analog, is a candidate for clinical trial. In the present study, we examined its biological stability in vitro, antitumor activity in vitro and in vivo, and pharmacokinetics. Although TEI-9826 was rapidly hydrolyzed to the carboxylic acid form (TOK-4528), TOK-4528 as well as Delta12-prostaglandin J2 (PGJ2) were found to be stable in rat, mouse and human serum in vitro.

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One of the delta7-prostaglandin A1 derivatives with unique antitumor activities, 13,14-dihydro-15-deoxy-delta7-prostaglandin-A1-methyl ester, was integrated into lipid microspheres (Lipo-TEI9826) and examined for its antitumor effect in vitro and in vivo. The in vitro relative resistance of human ovarian cancer, A2780CP, to cisplatin (CDDP) and Lipo-TEI9826 was 27.3 and 2.

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Prostaglandin E receptor EP3D is coupled to stimulation and inhibition of adenylate cyclase and stimulation of phosphatidylinositol turnover. To examine the roles of the interaction of the carboxylic acid of an agonist and its putative binding site, the arginine residue in the seventh transmembrane domain of EP3D, in receptor-G protein coupling, we have mutated the arginine to the non-charged glutamine. TEI-3356, an EP3 agonist with a negatively charged the carboxylic acid, and TEI-4343, a non-charged methylester of TEI-3356, inhibited the forskolin-stimulated cAMP formation in the same concentration-dependent manner, but stimulation of basal cAMP formation and Ca2+ mobilization by TEI-4343 was much lower than that by TEI-3356.

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Recently, we cloned cDNAs for the three mouse PGE receptor subtypes, EP1, EP2 and EP3, and the prostacyclin receptor, and established cells that stably express each receptor. We examined the selectivity of TEI-3356, an isocarbacyclin analogue, compared with other EP agonists, sulprostone and misoprostol, using Chinese hamster ovary cells expressing each cloned receptor. TEI-3356 selectively displaced the [3H]PGE2 binding to EP3-expressing cell membranes, but showed very low affinity for both EP1 and EP2.

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