title: [Recent advances in hypoxic cell radiosensitizer].
abstract: The comparative studies on the radiosensitizing efficacy of misonidazole (MISO) and SR-2508, a new 2-nitroimidazole which is less neurotoxic than MISO, were performed using C3H/He mouse mammary tumors. The enhancement ratios of 1.42 for 0.5 mmole/kg of MISO and 1.82 for 1.5 mmole/kg of SR-2508, the equitoxic dose to MISO, were obtained when each drug was administered in combination with a single dose of radiation. When the radiation was delivered in three and five fractions, enhancement ratios decreased to 1.15 and 1.11 for MISO while they remained at 1.40 and 1.34 for SR-2508 respectively. Potentiating effect of diethyl maleate (DEM) on the radiosensitization of MISO was also studied using the same experimental tumor. Although DEM, in itself, has a radiosensitizing effect in the dose range of more than 600mg/kg combined use of DEM and MISO showed more efficient synergism, e.g., the enhancement ratio of 0.5 mmole/kg of MISO increased from 1.42 to 2.06 when it was given in combination with 760 mg/kg of DEM. However, synergistic effects of MISO and DEM observed were dependent upon given dose of each drug. i.e.
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D017341:Etanidazole; D008298:Maleates / Q000008:administration & dosage*; D051379:Mice; D008809:Mice, Inbred C3H; D008920:Misonidazole / Q000008:administration & dosage*; D009374:Neoplasms, Experimental / Q000473:pathology / Q000532:radiotherapy*; D009593:Nitroimidazoles / Q000008:administration & dosage*; D010100:Oxygen / Q000502:physiology*; D010101:Oxygen Consumption; D011838:Radiation-Sensitizing Agents
chemical_list: D008298:Maleates; D009593:Nitroimidazoles; D011838:Radiation-Sensitizing Agents; D017341:Etanidazole; D008920:Misonidazole; C014476:diethyl maleate; D010100:Oxygen