Electroosmosis tissue

The mechanisms of the necrosis of the cancer tissue by electrochemical treatment (ECT) are complex and not fully understood although the nature of several factors involved has been indicated. Nordenstrom pointed out the importance of electroosmosis, electrophoresis, electrode reactions, pH changes and the general drastic change in the microenvironment of the cancer tissue10,18 during ECT this and related work has been reviewed by Nilsson and coworkers.19... 

In order to explain all the salient features of the key experimental results on ECT (viz. listed as 1. to 6. at the beginning of Section II, Phenomenology of ECT), Vijh25 proposed a detailed electrochemical mechanism in which electroosmosis of the tissue (and thence water movement from anode to cathode) and electrode reactions (thence necrosis of the tissue, pH changes etc.) play the dominant roles. In particular, he presented a model and some quantitative considerations that delineate Nordenstrom s idea of electroosmosis through the narrow interstitial channels lined with fixed charges as the mechanism of the electrochemical destruction of the tumor tissue.10 Also he examined the role of electrode reactions and other events as possible contributory factors, as follows25 in Section III.2. 

Figure 8. Electroosmosis depicted in the negatively charged tumor tissue wall enclosing an interstitial channel carrying extracellular liquid the water movement follows the direction of the field, i.e., always from the anode to the cathode.25...

The current was applied in the form of electrical pulses in order to permeabilize the membranes of the tumor cells for the entry of the chemotherapeutic agent bleomycin which is a very potent cytotoxic molecule. Clinical complete responses were achieved in 56.4% of the tumors and partial responses were observed in 28.9% of the tumors. This work is thus not strictly electrochemical treatment in the sense of Nordenstrom18 and Xin32 but is rather chemotherapy aided by electrochemical-driven movement of ions, molecules and drugs etc. (e.g., by electroosmosis, electrophoresis) into the tissue regions targeted for necrosis, as in several studies28,51,93 94 described earlier within this chapter. 

Iontophoresis by definition is the process of transport of ions into or through a tissue by the use of an applied potential difference across the tissue [52], Depending on the physicochemical characteristics of a molecular species, electrorepulsion is usually the primary mechanism of transdermal transport for ions, whereas electroosmosis and increased passive diffusion (as a result of the reduced barrier properties) are more prominent for neutral species [53]. In contrast, enhancement in flux for neutral or weakly charged species during electroporation arises predominantly from the reduced barrier properties of the membrane, whereas direct electrorepulsion is usually of secondary importance [25],... 

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