The influence of vinblastine (VLB) in combined chemotherapy on tumor cell membrane fluidity of a patient with exulcerated soft tissue sarcoma was studied by the electron paramagnetic resonance method (EPR). Tissue samples were taken before and after applications of VLB, Cis-Platinum (CDP) and combined intraarterial chemotherapy (IAC) and incubated with the spin probe, the palmitic acid methylester spin label analog, MeFasl (10, 3) incorporating into the cell membranes. EPR spectra of the labelled tissue samples were measured. Within few days after application of the chemotherapeutic drugs some oscillations of the membrane fluidity in the tissue were observed, while after a longer period of few weeks the relative amount of cells with greater membrane fluidity was found to decrease. Furthermore, an unexpected gradual increase in the EPR signal intensity after incubation of the tissue with the spin probe, probably due to an oxidative process in this particular sarcoma tissue was observed. These data could be useful for understanding of drug induced changes in cell membranes and for future timing of drug treatments in combined schedules.
Antineoplastic Combined Chemotherapy Protocols Electron Spin Resonance Spectroscopy