Response to motexafin gadolinium and ionizing radiation of experimental @entity35 prostate and XXXX .

@entity263 @entity5 @entity32735 @entity32736 @entity2 @entity35
PURPOSE: To investigate the responses of two experimental @entity35 @entity5 to single and fractionated X-ray doses whether or not combined with @entity32735 ( @entity32736 ), and the distribution of @entity32736 in @entity5 using MRI. METHODS: L44 @entity2 in BN @entity35 and @entity263 in Copenhagen @entity35 were grown subcutaneously. @entity32736 at concentrations of 8.7 to 25.1 micro mol/kg was administered 2 h before or just before treatments with single and fractionated X-ray doses. @entity5 volume growth delay was the endpoint used. The two-dimensional distribution of the @entity32736 concentration in time was analyzed simultaneously in slices through the center of @entity5 using MRI. Directly after the MRI experiments, @entity5 sections were stained for cytoplasm, nuclei, and microvessel endothelium. RESULTS: @entity32736 at different concentrations administered a few minutes or 2 h before X-ray doses produced no radiation enhancement in the two @entity5 models. The @entity32736 concentration as determined by MRI was maximal 5 min after injection and decreased slowly thereafter. In a representative section at the center of the @entity5 , the microvessel density is nearly homogeneous and correlates with a nearly homogeneous @entity32736 distribution. Hardly any @entity32736 is taken up in underlying muscle tissue. CONCLUSION: No radiosensitization was observed for the different irradiation regimens. The distribution of @entity32736 is nearly homogeneous in the @entity5 and hardly any @entity32736 is taken up in underlying muscles. Our negative results on radiosensitivity in our two @entity5 models raise questions about the efficacy of @entity32736 as a general radiosensitizing agent.
