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T Tokuyasu

Publications and source records attributed to T Tokuyasu.

8 recordsLinked to original sources
PubMed2000

Halonium ion-mediated reaction of unsaturated hydroperoxy acetals. Competition between the formation of cyclic peroxides and the migration of the methoxy (or hydroxy) group.

Monoozonolyses of dienes 2 in methanol gave in each case the corresponding unsaturated alpha-methoxy hydroperoxides 3. Capture of 2-alkyl-substituted cyclohexanone oxides by methanol was highly diastereoselective, thereby providing exclusively the hydroperoxides derived from attack by methanol from the less hindered face of the carbonyl oxide intermediates. Halonium ion-mediated reactions of the hydroperoxides 3 gave the novel methoxy- or hydroxy-migrated products, together with the expected halogen-substituted 1, 2-dioxanes and/or 1,2-dioxepanes, the composition of the product mixture being a function of the halogenating agent utilized and the structure of 3.

Acetals↗
PubMed1984

[Immunocytochemical localization of carcinoembryonic antigen (CEA) and transport of CEA into the blood vessels in gastric cancer].

CEA was localized in the luminal border, cytoplasm, but not in mucus, in Signet ring cell carcinoma (sig) and mucinous carcinoma (muc). Electronmicroscopically, CEA was localized in the glycocalyx of the microvilli and microvesicles of the cytoplasm. The histologically different cancer types showed no difference in the localization of T-CEA. We also studied P-CEA elevating factors in 38 CEA-positive (++) patients manifesting subserosal (ss) or deeper invasion. No remarkable findings were obtained. When P-CEA elevating factors were studied in 20 patients with (+) CEA reaction and ss or deeper invasion, we found that the incidence of por was high in P-CEA negative cases. In particular, the por incidence was significantly low (p less than 0.01) in patients with scirrhous type. High P-CEA levels were detected in blood adjacent to the cancer. Among 6 cases with negative P-CEA in the vessels adjacent to the cancer whose T-CEA reactions were (++) or (+), and who manifested ss or deeper invasion, there was a high incidence of por (5 cases) and scirrhous type (4 cases), histologically.

Adenocarcinoma↗
PubMed1979

An improved method for the preparation of chondroitin by solvolytic desulfation of chondroitin sulfates.

By heating the pyridinium salts of chondroitin 4- and 6-sulfates in dimethyl sulfoxide containing 10% of water or methanol at 80 degrees C for 1--5 h, several chondroitin preparations with sulfur contents of 0.02--1.05% were prepared in 83--96% yields, respectively. Chemical properties of the preparations, such as degrees of desulfation and of depolymerization, were compared with those of the products obtained by the previously described methods.

Chemical Phenomena↗