Abstract
BackgroundThe modified Gompertz equation has been proposed to fit experimental data for direct current treated tumors when multiple-straight needle electrodes are individually inserted into the base perpendicular to the tumor long axis. The aim of this work is to evaluate the efficacy of direct current generated by multiple-electrode arrays on F3II mammary carcinoma that grow in the male and female BALB/c/Cenp mice, when multiple-straight needle electrodes and multiple-pairs of electrodes are inserted in the tumor.MethodsA longitudinal and retrospective preclinical study was carried out. Male and female BALB/c/Cenp mice, the modified Gompertz equation, intensities (2, 6 and 10 mA) and exposure times (10 and 20 min) of direct current, and three geometries of multiple-electrodes (one formed by collinear electrodes and two by pair-electrodes) were used. Tumor volume and mice weight were measured. In addition, the mean tumor doubling time, tumor regression percentage, tumor growth delay, direct current overall effectiveness and mice survival were calculated.ResultsThe greatest growth retardation, mean doubling time, regression percentage and growth delay of the primary F3II mammary carcinoma in male and female mice were observed when the geometry of multiple-pairs of electrodes was arranged in the tumor at 45, 135, 225 and 325o and the longest exposure time. In addition, highest direct current overall effectiveness (above 66%) was observed for this EChT scheme.ConclusionsIt is concluded that electrochemical therapy may be potentially addressed to highly aggressive and metastic primary F3II murine mammary carcinoma and the modified Gompertz equation may be used to fit data of this direct current treated carcinoma. Additionally, electrochemical therapy effectiveness depends on the exposure time, geometry of multiple-electrodes and ratio between the direct current intensity applied and the polarization current induced in the tumor.
Highlights
The modified Gompertz equation has been proposed to fit experimental data for direct current treated tumors when multiple-straight needle electrodes are individually inserted into the base perpendicular to the tumor long axis
Exposure time and electrode array geometries are included in the parameters of modified Gompertz equation
This may be argued because the complete response of the primary F3II mammary carcinoma after electrochemical therapy (EChT) application is not observed for the condition (i/ i0) < (i/i0)u
Summary
The modified Gompertz equation has been proposed to fit experimental data for direct current treated tumors when multiple-straight needle electrodes are individually inserted into the base perpendicular to the tumor long axis. The data of Ehrlich and fibrosarcoma Sa-37 primary tumors [3] and highly aggressive and metastatic primary F3II mammary carcinoma [5] are adequately fitted with this equation This validation of MGE is carried out for different values of DC intensity (i) and time of exposure of it (texp), fixing the same electrode array geometry. The stationary partial response [4], other findings [6] and how space–time distribution of the tumor density changes for each tumor response post-treatment [7] is revealed from the simulation of MGE These theoretical and experimental results are valid when two or more collinear electrodes with alternating polarities inserted perpendicular to the larger diameter of the tumor are used
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