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[en] There is little study on the hydrolysis reactions of Nheteroarylimidazole derivatives in comparison with those of N-acylimidazoles. Some years ago, we reported the hydrolysis reactions of N-heteroaryl-2-phenylimidazoles, Nfuroyl- 2-phenylimidazole and N-thenoyl-2-phenylimidazole. In the hydrolysis reactions of these compounds, we found a change of the rate dertermining step in acidic regions. These results are very unique even though the feature of hydrolysis reactivity of N-acylimidazole derivatives depends on the structure of N-acylimidazole. But, when one changes the acyl group with the heteroaryl group to the benzoyl group having same leaving group, the pH rate profile for the hydrolysis reaction of N-benzoyl-2-phenylimidazole observed to be related with the diprotonated species of the substrate in acidic region. Finally, in this study, we have found that the rate accelerating effect by the substituent, NO2 group in the leaving group is small. The large kOH value in OH'- catalyzed hydrolysis reaction should be explained that the resonance interaction of the leaving group itself is more important than that between N-1 atom of the imidazole and the carbonyl carbon.
[en] Ethical committee and patient informed consent was obtained to conduct a Phase I study to determine a safe single dose of SR 2508 which may be combined with 0.75 g/m2 or Ro 03-8799 (both misonidazole analogues). It was shown that a single dose of 3 g/m2 SR 2508 can be combined with 0.75 g/m2 Ro 03-8799, giving a clear potential for therapeutic advantage without increased toxicity. This is now being explored further using a multiple dose schedule. (U.K.)
[en] The radioresistant tumors such as lung adenocarcinoma and desmoid tumor were treated with the intermittent use of the combined therapy which consisted of misonidazole, ACNU and irradiation and which was tried several times during the usual radiotherapy. This combined therapy used in the early stage of the radiotherapy was more effective than that in the late stage. It is presumed that the clinical radioresistance can be modified by the disturbance of tumor cell Kinetics, namely, by increasing the growth fraction which is accompanied by the increase of the cell loss factor, even if the intrinsic radiosensitivity is unchangeable. (author)
[en] The value of the dog as an animal system in which to test the pharmacological, toxicological and sensitising properties of new hypoxic cell radiosensitising agents is described in relation to misonidazole, desmethylmisonidazole, SR-2508 and SR-2555, and the more general role to be played by veterinary oncology in linking the laboratory evaluation of anti-cancer agents with their ultimate clinical application in man is outlined. (U.K.)