Low-intensity Electric Current Research Articles

The Electricidal Effect: Reduction of Staphylococcus and Pseudomonas Biofilms by Prolonged Exposure to Low-Intensity Electrical Current

The activity of electrical current against planktonic bacteria has previously been demonstrated. The short-term exposure of the bacteria in biofilms to electrical current in the absence of antimicrobials has been shown to have no substantial effect; however, longer-term exposure has not been studied. A previously described in vitro model was used to determine the effect of prolonged exposure (i.e., up to 7 days) to low-intensity (i.e., 20-, 200-, and 2,000-microampere) electrical direct currents on Pseudomonas aeruginosa, Staphylococcus aureus, and Staphylococcus epidermidis biofilms. Dose- and time-dependent killing was observed. A maximum of a 6-log(10)-CFU/cm(2) reduction was observed when S. epidermidis biofilms were exposed to 2,000 microamperes for at least 2 days. A 4- to 5-log(10)-CFU/cm(2) reduction was observed when S. aureus biofilms were exposed to 2,000 microamperes for at least 2 days. Finally, a 3.5- to 5-log(10)-CFU/cm(2) reduction was observed when P. aeruginosa biofilms were exposed to electrical current for 7 days. A higher electrical current intensity correlated with greater decreases in viable bacteria at all time points studied. In conclusion, low-intensity electrical current substantially reduced the numbers of viable bacteria in staphylococcal or Pseudomonas biofilms, a phenomenon we have labeled the "electricidal effect."

Electrical impedance tomography through constrained sequential linear programming: a topology optimization approach

Electrical impedance tomography (EIT) is an imaging method that estimates conductivity distribution inside a body. In EIT, images are obtained by applying a sequence of low intensity electrical currents through electrodes attached to the body. Although in EIT there are serious difficulties to obtain a high-quality conductivity image, for medical applications this technology is safer and cheaper than other tomography techniques. The EIT deals with an inverse problem in which given the measured voltages on electrodes and a finite element (FE) model, it estimates the conductivity distribution, which are parameters of the FE model. In this work, the topology optimization method is applied as a reconstruction algorithm to obtain absolute images in EIT. It is an optimization method that has been applied successfully to structural mechanical applications and consists of systematically finding a conductivity distribution (or material distribution) in the domain that minimizes the difference between measured voltages and voltages calculated by using a computational model. This algorithm combines the finite element method and sequential linear programming (SLP) to solve the inverse problem of EIT. The SLP allows us to easily apply some regularization schemes based on included constraints in the topology optimization problem. Constraints based on image tuning control and weighted distance interpolation (WDI) are proposed, while a material model is applied to ensure the relaxation of the optimization problem. A new formulation to analytically perform the sensitivity analysis is proposed, using Maxwell's reciprocity theorem. To illustrate, the implemented algorithm is applied to obtain conductivity image distributions of some 2D examples using numerical and experimental data.

Physical Therapy for the Equine Back

Before a physical therapy and rehabilitation program is suggested, the end requirement must be considered. All physiotherapeutic machines are subject to laboratory screening. In the United States, the approval of the Food and Drug Administration is required; in the United Kingdom, certification by the National Physics Laboratory has been required by law since January 1996. Laboratory experiments are continually conducted to examine and evaluate the effects on tissues of varied electrical waveforms, low-intensity electrical currents, sound waves, and light rays delivered by a variety of therapeutic apparatuses. It is interesting to note that the tissues used for this work are derived from the rabbit, rat, and chick embryo. If these investigative procedures demonstrate benefit to tissue behavior following trauma in laboratory animals, they are then considered to be of benefit to humans. Surely, it must follow that equal benefit is to be derived by other species with similar tissues. Despite veterinarian prejudice to the contrary and by careful case selection rather than random application, horses can profit from the application of electrotherapy and derive benefit from rehabilitation; thus, an informed physical therapist should be considered a useful member of a "care" team. Because no two cases are ever the same, it is impossible to write a "recipe" book stating exactly the dosage, treatment time, or applications per week or per day. Success depends on an in-depth assessment of individual needs followed by an informed choice of therapy. In the case of physical therapy, this necessitates the use of the appropriate modality at the appropriate time, always taking into account the fact that tissue is living and is therefore in a continually changing state. The art of the physical therapist is to read the situation each time a patient is seen and to proceed according to the findings of the moment. The author regrets that there are no double-blind trials to quote or published research available to substantiate rehabilitation methods. The therapy principles relating to proprioceptive input, cortical re-education, muscle recoordination, and atrophy following both micro- and macrotrauma have been transferred in field work from humans to horses.

Comparison of electromotive drug administration with ketorolac or with placebo in patients with pain from rheumatic disease: a double-masked study

This study was undertaken to assess the efficacy of ketorolac compared with placebo when delivered by electromotive drug administration (EMDA) in patients with pain from rheumatic disease. In EMDA, or iontophoresis, a low-intensity electric current is applied over the skin to deliver medication into body tissues. Although EMDA has been used to treat patients with various diseases, controlled studies are lacking in patients with rheumatic disease. This double-masked study included 60 patients (43 women and 17 men) aged 31 to 80 years with the following conditions: 12, epicondylitis; 30, scapulohumeral periarthritis; 10, gonalgia; and 8, metatarsalgia. They were divided randomly by a physician into 2 groups of 30 patients each for 5 sessions of active treatment (30 mg of ketorolac) or placebo (5 mL of normal saline). Treatment took place every other day for 20 minutes. Immediately before and after the five treatment sessions and 7 days after treatment ended, both patient and physician measured the degree of pain using a categoric scale (no pain, slight pain, intermediate pain, strong pain, and very strong pain) and evaluated pain intensity using the Scott and Huskisson Visual Analogue Scale (VAS). Seven days after treatment ended, both physician and patient judged the result of treatment using a second categoric scale (no improvement or intermediate, good, or very good result). Both ketorolac and placebo provided immediate, significant pain relief when delivered by EMDA, but only those patients receiving ketorolac experienced a further reduction in pain 7 days after treatment; those receiving placebo experienced a slight increase in pain. VAS values differed significantly between the two groups. Poor results (no improvement) were significantly higher in the placebo-treated group, while good results were significantly higher in the ketorolac-treated group. No patient reported any adverse effects during treatment. This study demonstrates that ketorolac relieves pain when delivered by EMDA and offers longer-lasting pain relief than does placebo.

Stimulation of sciatic nerve regeneration in the adult rat by low-intensity electric current

Morphometric analysis was used to evaluate regeneration in transected sciatic nerves of adult rats constantly stimulated with low-intensity direct current. The ends of the cut nerve were separated by a distance of 5 mm and inserted into a Silastic tube. Histological and electron microscopy criteria were used to measure and evaluate the cross-sectional area and the structure of the bridge connecting the distal and proximal stumps. After 3 weeks of stimulation (10 μA DC with distal cathode) the stimulated animals showed a cross-sectional bridge area twice the size of nonstimulated controls. The number of myelinated and unmyelinated axons, and the vascular areas, were also larger in the experimental group. This is the first quantitative analysis of low-intensity direct current-enhanced peripheral nerve regeneration in adult mammals.