[Polarographic analysis of tumor tissue oxygen tension after hyperthermia combined with misonidazole].
For the purpose to analyse the influence of a thermosensitizing drug, misonidazole (MIS), on tissue oxygen tension (TpO2), TpO2 in human gastric cancer tissue (H-23) was measured by a polarographic method. MIS, 500 mg/kg, was given i.p. and then the heat treatment was done in a water bath at 43.5 +/- 0.1 degrees C for 23 minutes. A second treatment was performed to develop thermotolerance at the following intervals: 24 hours, 72 hours, 5 days, and 7 days. Tumor doubling time was shortest at 72-hour interval, i.e., the maximal thermotolerance of the tumor developed at 72-hour interval, whereas the tumor doubling time in case of combined use of MIS was shortest at 24-hour interval. TpO2 in the 72-hour interval treatment decreased soon after hyperthermia, and returned to a pre-heated value 3 hours after, whereas in the other 3 treatments the recovery time was 6 to 12 hours. On the other hand, in 24-hour interval of the combined use of MIS, the post-thermal value of TpO2 was about a half of the pre-thermal value and recovered 24 hours after. In the 5- and 7-day interval treatments, TpO2 declined notably and did not return to the pre-thermal value during 24 hours. These data suggest that the thermo-sensitizing effects of MIS were brought about by prolonged and extreme decrease in TpO2.
Kokubun
M
M
First Dept. of Surgery, School of Medicine, Chiba University.
Fujimoto
S
S
Shrestha
R D
RD
Ohta
M
M
Kobayashi
K
K
Kiuchi
S
S
Konno
C
C
Fujita
M
M
Taguchi
T
T
Okui
K
K
D000222:Adaptation, Physiological; D000818:Animals; D003131:Combined Modality Therapy; D006358:Hot Temperature; D006801:Humans; D006979:Hyperthermia, Induced; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D008920:Misonidazole / Q000627:therapeutic use*; D009368:Neoplasm Transplantation; D010100:Oxygen / Q000502:physiology*; D010313:Partial Pressure; D011048:Polarography; D013274:Stomach Neoplasms / Q000188:drug therapy / Q000503:physiopathology / Q000628:therapy*; D014183:Transplantation, Heterologous
D008920:Misonidazole; D010100:Oxygen