title: Halogenated pyrimidine sensitization of low dose rate irradiation in human malignant glioma.
abstract: OBJECTIVE
  To determine the potential advantage of combining halogenated pyrimidine radiosensitization and continuous low dose rate irradiation in human malignant glioma.
  
  
  METHODS
  An established glioma line (U-251) was incubated with 5-bromo-2-doxyuridine (BrdUrd) at clinically achievable concentrations at three dose rates of interest--100 cGy/min (typical of external beam therapy), 43 cGy/hr (typical of temporary afterloaded implants), and 12 cGy/hr (typical of permanent implants).
  
  
  RESULTS
  After exposure to 1 microM BrdUrd, the greatest enhancement ratio was seen at the 12 cGy/hr dose rate, implying a BrdUrd induced inverse dose rate effect independent of a G2M block. Under these conditions, the mean inactivation dose after 1 microM BrdUrd exposure was equivalent for 100 cGy/min and 12 cGy/hr.
  
  
  CONCLUSIONS
  These results support the use of halopyrimidines as sensitizers of temporary afterloaded and permanent implants.
authors.affiliation: Dept. of Radiation Oncology, University of Michigan Medical Center, Ann Arbor 48109.
authors.forename: P W
authors.initials: PW
authors.lastname: McLaughlin
authors.forename: W R
authors.initials: WR
authors.lastname: Mancini
authors.forename: P L
authors.initials: PL
authors.lastname: Stetson
authors.forename: H S
authors.initials: HS
authors.lastname: Greenberg
authors.forename: N
authors.initials: N
authors.lastname: Nguyen
authors.forename: H
authors.initials: H
authors.lastname: Seabury
authors.forename: D B
authors.initials: DB
authors.lastname: Heidorn
authors.forename: T S
authors.initials: TS
authors.lastname: Lawrence
mesh_terms: D001973:Bromodeoxyuridine / Q000627:therapeutic use*; D004307:Dose-Response Relationship, Radiation; D005910:Glioma / Q000532:radiotherapy*; D006801:Humans; D066298:In Vitro Techniques; D011838:Radiation-Sensitizing Agents / Q000627:therapeutic use*; D011879:Radiotherapy Dosage; D015996:Survival Rate; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000528:radiation effects
chemical_list: D011838:Radiation-Sensitizing Agents; D001973:Bromodeoxyuridine