A multi-channel stimulator and electrode array providing a rotating current whirlpool for electrical stimulation of wounds.

When electrical stimulation is used on wounds, the electrical current has difficulty penetrating areas where there is necrotic tissue. Further, for an irregularly shaped wound, current distribution is poor in some areas of the wound since conventional two-electrode delivery systems provide the greatest current in a line directly between the electrodes. A new stimulator and electrode system is described which uses three electrodes spaced around a wound to disperse current more evenly. The stimulator senses tissue impedance and then redirects current by altering its Thevenin's output impedance for each electrode; each of the three electrodes becomes the active one in sequence while the remaining are the sink electrodes. Eight subjects were examined to test the stimulator. Electrical stimulation was applied to the skin above the quadriceps muscle at currents of 15 mA in six subjects without wounds and in two subjects with wounds. The relationship between electrode position and current dispersion on the skin was examined with a two-electrode vs. a three-electrode system to set stimulation parameters for the computer. The results showed that the three-electrode system could (1) detect areas of the skin with high impedance; (2) compensate by altering the Thevenin's output impedance at each of the three electrodes to shift current to high impedance areas; (3) provide uniform current across the skin as assessed by skin current and blood flow measurements with a laser Doppler flow imager.

[Effect of vitamin C (V.C) on thermal sensitivity of Lewis tumor].

In this paper, the effect of V.C on thermal sensitivity of the tumor and normal tissues was studied. Average peak reaction and RD50 (50% reaction dosage) were used to evaluate the effect of V.C on thermal sensitivity of the normal tissue. Tumor cure rate and TCD50 (50% tumor cure dosage) were used to evaluate the effect of V.C on that of the tumor tissue. In all mice injected by V.C locally, the average peak reaction markedly increased, RD50 decreased by 1-2 fold; the tumor cure rate was obviously elevated, TCD50 was significantly reduced except those treated by 20' hyperthermia. TGF (therapeutic gain factor) was 1.76. These results indicate that V.C can increase the thermal sensitivity of tumor and normal tissues but the effect on tumor tissue is selective.