The role of tumor volume in 'reoxygenation' upon cyclophosphamide treatment.
The effect of cyclophosphamide (CP) injection (60 mg/kg i.p., single dose) on volume growth and tissue oxygenation (pO2 distribution) was investigated in rat DS-sarcomas. CP was administered 4 days after subcutaneous (s.c.) tumor implantation (volume approximately 0.35 ml). Polarographic pO2 measurements were performed in the subcutis at the hind foot dorsum and in tumors 72 h after CP administration. The oxygenation status of these tissues was compared with that of saline-treated controls. CP-injection caused a mean growth delay of 11 days in DS-sarcomas and had no impact on the oxygenation status of the subcutis. In contrast, in s.c. growing DS-sarcomas the pO2 distribution improved significantly when treated tumors (0.59 ml volume) were compared with their untreated counterparts (1.15 ml volume). Comparison of the oxygenation data of CP-treated tumors with size-matched controls revealed an identical oxygenation status in the experimental tumors used. Thus, when 'reoxygenation' is discussed, one should consider whether it is solely the result of tumor shrinkage or a volume-independent phenomenon.
Busse
M
M
Institute of Physiology & Pathophysiology, University of Mainz, Germany.
Vaupel
P W
PW
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002245:Carbon Dioxide / Q000097:blood; D002455:Cell Division / Q000187:drug effects; D003520:Cyclophosphamide / Q000494:pharmacology*; D005260:Female; D006400:Hematocrit; D006454:Hemoglobins / Q000378:metabolism; D007700:Kinetics; D008297:Male; D010100:Oxygen / Q000032:analysis / Q000097:blood; D010101:Oxygen Consumption / Q000187:drug effects*; D010313:Partial Pressure; D011048:Polarography; D051381:Rats; D017207:Rats, Sprague-Dawley; D012513:Sarcoma, Experimental / Q000098:blood supply / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology*; D013997:Time Factors
D006454:Hemoglobins; D002245:Carbon Dioxide; D003520:Cyclophosphamide; D010100:Oxygen