title: Time scale of radiation damage by 2,4-dinitrophenyl-aziridine (CB 1954) in Chinese hamster cells: a rapid-mix study.
abstract: A rapid-mix device was used to study the time-scale of radiation sensitization of hypoxic cells by CB 1954, a monofunctional alkylating agent. It has an electron affinity (E1(7)-385 mV) similar to that of misonidazole but its effectiveness as a sensitizer occurs at a five-fold lower concentration under stationary-state conditions. In the rapid-mix study, the enhancement ratio (e.r.) value of 1 mmol dm-3 CB 1954 rapidly rises to 1.75 within 120 ms, with no further rise by 500 ms. The e.r. obtained is lower than that observed under stationary-state conditions for a similar concentration. The data suggests that CB 1954 sensitizes by at least two independent mechanisms.
mesh_terms: D000620:Aminoimidazole Carboxamide / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D000964:Antimetabolites, Antineoplastic; D001388:Aziridines / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D001389:Azirines / Q000494:pharmacology*; D002460:Cell Line; D002470:Cell Survival / Q000528:radiation effects; D006224:Cricetinae; D003412:Cricetulus; D011837:Radiation-Protective Agents / Q000494:pharmacology; D011838:Radiation-Sensitizing Agents / Q000037:antagonists & inhibitors; D013997:Time Factors
chemical_list: D000964:Antimetabolites, Antineoplastic; D001388:Aziridines; D001389:Azirines; D011837:Radiation-Protective Agents; D011838:Radiation-Sensitizing Agents; D000620:Aminoimidazole Carboxamide; C055152:2-phenyl-4-amino-5-imidazolecarboxamide; C100099:tretazicar