Amelanotic melanoma of the root of the tongue in a canine patient treated by electrochemotherapy

F MAGLIETTI; S MICHINSKI; RICOTTI I; MAURE P; L. MIR; N OLAIZ; MARSHALL G

Conferencia; 7th Conference on Experimental and Translational Oncology. COST TD 1104 Action; 2013

We present experimental evidence of the existence of pH fronts emerging from both electrodes during tissue electroporation (EP) based treatments for conditions typical to many studies found in the literature. It is also shown that those fronts are immediate and substantial. The presence of pH fronts is indirectly measured through the evanescence time (ET), that is, the time taken by the tissue buffer to neutralize them. In order to compute the ET, the evolution of a pH indicator was imaged at a series of time intervals, and a four-cluster fuzzy-c-means method was used to segment the pixels corresponding to the pH indicator at every frame. The ET was computed as the time when the number of pixels was 10% of those in the initial frame. While in EP treatments such as reversible (ECT) and irreversible electroporation (IRE) the ET is very fast due to biological buffers present in the tissue (less than 5 s, though enough to cause minor injuries), in electrogenetransfer (EGT), ET is much slower and enough to denaturate plasmids and produce cell damage. When any of the pulse parameters is doubled or tripled the ET grows and remarkably, when any of the pulse parameters in EGT is halved, the ET drops significantly. Reducing the pH change has relevant implications for EGT treatment efficiency, due to much less plasmid damaging and less cell loss.