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Thymidine photosensitization

Fluorouracil Inhibition of the enzyme thymidylate synthase, the rate-limiting step in thymidine formation. Dose-limiting Myelosuppression and mucositis with bolus administration Diarrhea and hand-foot syndrome with continuous infusion Additional toxicities Skin discoloration, nail changes, photosensitivity, and neurologic toxicity... [Pg.1350]

Inhibition of mitogen-stimulated thymidine incorporation in human peripheral blood mononuclear cells has been reported as a method for screening for photosensitizers. Cells from at least three volunteers were used for testing each chemical. [Pg.2651]

One-electron oxidation reactions of pyrimidine bases are also well established, mostly through the study ofthe menadione-mediated type I photosensitization of 2 -deoxycytidine and thymidine [3]. The radical cations once formed may undergo two competitive pathways. [Pg.181]

Hydration of the thymidine radical cation leads to the predominant formation of the oxidizing 6-hydroxy-5,6-dihydrothymid-5-yl radical whereas deprotonation mostly generates the methyl-centered radical (Fig. 4). As already pointed out, these two pyrimidine radicals are also produced upon reaction with OH. However, the methyl-centered radical represented only 5% of base radicals when produced by OH while it corresponds to 30% of the thymidine radicals produced upon one-electron oxidation. Type I photosensitization of 2 -deoxy-cytidine leads to the formation of the 6-hydroxy-5,6-dihydro-2 -deoxycytidil-5-yl radical also produced upon reaction with OH. Additional oxidative pathways involve the formation of 2-deoxyribonolactone and free cytosine as well as production of 2 -deoxyuridine as the result of deprotonation ofthe pyrimidine radical cation at Cl and NH2 group, respectively. [Pg.182]


See other pages where Thymidine photosensitization is mentioned: [Pg.15]    [Pg.16]    [Pg.616]    [Pg.695]    [Pg.915]    [Pg.926]    [Pg.929]    [Pg.1483]    [Pg.1493]    [Pg.1223]    [Pg.1265]    [Pg.616]    [Pg.695]    [Pg.915]    [Pg.926]    [Pg.929]    [Pg.377]    [Pg.641]    [Pg.1051]    [Pg.377]    [Pg.641]    [Pg.176]    [Pg.177]    [Pg.167]   
See also in sourсe #XX -- [ Pg.929 ]




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Thymidine

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