Oxygen diffusivity in tumor tissue (DS-Carcinosarcoma) under temperature conditions within the range of 20?40 C

Abstract

The O₂ diffusion constants D and K of tumor tissue (DS-Carcinosarcoma in the rat kidney) were determined at temperatures of 20, 30, 37, and 40°C. The following mean values were obtained for the conditions of 37°C: D=1.75·10⁻⁵ cm²/s and K=1.9·10⁻⁵ mlO₂/cm·min·atm. Within the range of 20–40°C, temperature variations in tumor tissue cause changes in the O₂ diffusion coefficient D of 2.0–2.5%/°C and in the Krogh O₂ diffusion constant K of 0.5–1.5%/°C. The measured O₂ diffusion constants for tumor tissue correspond to values of normal tissue with similar water content. This indicates that the insufficient O₂ supply in DS-Carcinosarcoma is due not to unfavorable O₂ diffusivity of the tumor tissue but rather to a decreased convective O₂ transport and to insufficient capillarization. An analysis of O₂ diffusion in DS-Carcinosarcoma tissue using the determined O₂ diffusion constants lead to the result that, under the conditions of arterial normoxia and normocapnia, critical O₂ supply conditions are to be expected when the intercapillary distance exceeds approximately 120 μm.