Electrophoresis and diffusion in the plane of the cell membrane.

Electrophoretic and diffusional movements of concanavalin A (Con A) receptors and acetylcholine (ACh) receptors in the plane of the plasma membrane of mononucleate, spherical Xenopus myoblasts were studied by microfluorimetry and iontophoresis. We found that (a) a uniform electric field of 10 V/cm applied along the cell surface produces a partial accumulation of both types of receptors toward the cathodal pole of the cell within 30 min: (b) post-field relaxation of the culture results in the complete recovery of the uniform distribution of the Con A receptors within 10 min; and (c) in contrast to the Con A receptor in general, accumulation of ACh receptors by the electric field results in the formation of stable, localized receptor aggregates. Theoretical analyses were carried out for the distribution of charged membrane receptors at equilibrium between electrophoresis and diffusion, and for the rate of back diffusion after the removal of the field. These analyses indicated that, at 22 degrees C, the average electrophoretic mobility of the electrophoretically mobile population of the Con A receptors is about 1.9 X 10(-3) micron/s per V/cm, while their average diffusion coefficient is 5.1 X 10(-9) cm2/s

Antibacterial Activity of Positive and Negative Polarity Low-voltage Pulsed Current (LVPC) on Six Typical Gram-positive and Gram-negative Bacterial Pathogens of Chronic Wounds

The positive effect of electrical stimulation (ES) on wound healing has been shown in vitro and in vivo. On the basis of increased blood flow, protein denaturation, and stimulation of cellular defense, an antibacterial effect of ES is to be expected. Although the antibacterial effect of ES already has been demonstrated in vitro, little attention has been paid to the direct antibacterial effect of changing polarity of the applied current. The aim of this study was to investigate the antibacterial effect of positive and negative monophasic low-voltage pulsed current on typical Gram-positive and Gram-negative pathogens of chronic wounds. Using the Dermapulse®-System, three Gram-negative (Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae) and three Gram-positive (Staphylococcus aureus, Staphylococcus epidermidis, Escherichia faecium) organisms were tested against positive and negative polarity low voltage pulsed current. All tested organisms were significantly reduced by ES. The reduction differed significantly between positive polarity and control and negative polarity and control, with the highest log10 reduction factor (RF) achieved with positive polarity. Using positive polarity, the maximum RF was measured for E. coli (median log10 RF 0.83; 25th percentile 0.59, 75th percentile 0.98) and the lowest for S. epidermidis (median log10 RF 0.20; 25th percentile 0.17, 75th percentile 0.24). Yet, there was no significant difference with positive ES against Gram-positive or Gram-negative organisms