Low-frequency Electric Currents Research Articles

Effect of the electrolipophoresis in the lipodystrophy treatment and its influence on lipid profile

Introduction: The excess of body adiposity and the hormonal action can lead to the accumulation of adipose tissue in certain parts of the body. The electrolipophoresis is a technique used to treat localized fat, by applying low frequency electrical currents that act directly on the adipocytes and lipids accumulated subcutaneously or epicutaneously. This electrical stimulation causes physiological modifications in the adipocyte, among them the increase in blood flow and cellular metabolism leading to lipolysis. Objective: This study aimed to prove, through the measurement of triglycerides in the blood, which is the most effective method of electrolipophoresis practical application in the promoted lipolysis. Methods: The old female patients aged from 49 to 62 underwent evaluation that measured the body mass index (BMI); perimetry performed with the use of measuring tape of the waist and abdomen region and the realization of abdominal (vertical) skinfold measurement with the use of adipometer. After the evaluation, the volunteers were divided into two groups in which one of them received subcutaneous application of electrolipophoresis equipment (needles) and the other one received epicutaneous electrolipophoresis application (plates). They were positioned and oriented about the procedure and received the practical application of electrolipophoresis (DGM equipment) twice a week for ten sessions of 60 minutes each. The dosage of triglycerides was performed in the first and last session. Results: There was a reduction in all evaluations performed, and a subcutaneous application shows more effective in the treatment of localized fat. Conclusion: With these findings was observed a reduction in abdominal measurement and decreased of triglycerides in the blood thus showing that treatment using plates or electrodes is effective in localized lipodystrophy. Despite the significant reduction of localized adiposity, further studies with more participants and sessions are needed to make this treatment, widely used in clinical practice of Dermato-Functional Physiotherapy, most reliable.

Fast evaluation of the Biot-Savart integral using FFT for electrical conductivity imaging

Magnetic resonance electrical impedance tomography (MREIT) and current density imaging (MRCDI) are emerging as new methods to non-invasively assess the electric conductivity of and current density distributions within biological tissue in vivo. The accurate and fast computation of magnetic fields caused by low frequency electrical currents is a central component of the development, evaluation and application of reconstruction methods that underlie the estimations of the conductivity and current density, respectively, from the measured MR data. However, methods for performing these computations have not been well established in the literature. In the current work, we describe a fast and efficient technique to evaluate the Biot-Savart integral based on the fast Fourier transform (FFT), and evaluate its convergence. We show that the method can calculate magnetic fields in realistic human head models in one minute on a standard computer, while keeping error below 2%.

Protection of personnel and patients in diagnosis and therapy with ionizing and non-ionizing radiation

Most of the sources used in physiotherapy use pulse magnetic fields; spark-discharges; radiofrequencies (RF); direct and low-frequency electric currents, electrical pulses; ultraviolet (UV) and infrared (IR) radiation; broad-spectrum lamps; lasers. The most relevant diagnostic sources are MRI scanners emitting static magnetic field, low-frequency fields, RF. The exposure of medical personnel to NIR depends on the type of transmitter, irradiation power, mode of operation, specific application, access of medical personnel to the treatment zone, shielding of the source and workplace, time duration of exposure. Devices for electric current therapy like pulses, ionophoresis therapy, vacuum therapy, emit magnetic field less than several μT. The devices for subthermal therapy emit RF energy up to 9,8 W/kg, compared to 0,4 W/kg basic restriction for whole body exposure. The average daily dose of the staff at 10 patients per day is 18,356 (V/m)2·h. The dose of medical personnel in protective chambers averaged per patient is WE = 23,88 (V/m)2·h. Regard to MRI equipment, the basic restrictions for static magnetic field for normal operating conditions exceed the action values for people at specific risk, also for risk of attracting ferromagnetic materials. In the case of the use of optical sources, power densities exceed the exposure limit values, and therefore the permissible stay is limited to minutes and seconds, and in some cases it is inadmissible. In cosmetic centers, sanatoriums and SPA centres, power densities are significant and some of them are not controlled (tanning beds and IPL systems). The laser systems applied in physiotherapy are mainly class 3R (visible range), which only pose a risk to the eyes, in some cases 1C. For some procedures, lasers of class 3B are also used which cause risk to the eye by intra-beam viewing as well as diffuse reflected radiation. In cosmetic centers where specific lamps and high class (4) lasers are used, there is a risk for serious skin burns and eye damage.

Hydrogalvanic baths as a method of medical rehabilitation: a literature review and the prospects for the clinical application

The hydrogalvanic baths provide a tool for the combined application of warm fresh water and low frequency electric current. These procedures are suitable for both systemic and local treatments. The mechanism behind their therapeutic action is based on synergistic effect of two therapeutic agents. This article presents the literature and historical review of the method as well as the current concept of hydrohalvanic therapy. The history of its development is associated with the improvement of the technical equipment and accumulation of clinical experience. Numerous studies carried out up to the present time have demonstrated that hydrohalvanic therapy can be effectively applied for the treatment of diabetic angiopathy, rheumatoid and gouty arthritis, fibromyalgia, ankylosing spondylitis. At the same time, the high potential of this method remains underestimated. At present, one of the most promising approaches to its clinical applications is the treatment of lumbosacral radiculopathy caused by degenerative vertebral disk lesions. The hydrogalvanic baths have analgesic, anti-inflammatory, and decongestant effects, improve microcirculation, and reduce sensory impairment. It is necessary to continue clinical investigations to obtain further evidence of the effectiveness of the method under consideration for the treatment of lumbosacral radiculopathy and to evaluate its short- and long-term effects. Their results will hopefully provide an opportunity to include the hydrogalvanic baths in the programs of medical rehabilitation of the patients presenting with lumbosacral radiculopathy.

A Study on Performance and Safety Tests of Electrosurgical Equipment.

Modern medicine employs a wide variety of instruments with different physiological effects and measurements. Periodic verifications are routinely used in legal metrology for industrial measuring instruments. The correct operation of electrosurgical generators is essential to ensure patient's safety and management of the risks associated with the use of high and low frequency electrical currents on human body. The metrological reliability of 20 electrosurgical equipment in six hospitals (3 private and 3 public) was evaluated in one of the provinces of Iran according to international and national standards. The achieved results show that HF leakage current of ground-referenced generators are more than isolated generators and the power analysis of only eight units delivered acceptable output values and the precision in the output power measurements was low. Results indicate a need for new and severe regulations on periodic performance verifications and medical equipment quality control program especially in high risk instruments. It is also necessary to provide training courses for operating staff in the field of meterology in medicine to be acquianted with critical parameters to get accuracy results with operation room equipment.

Electrical impedance spectroscopy-based defect sensing technique in estimating cracks.

A defect sensing method based on electrical impedance spectroscopy is proposed to image cracks and reinforcing bars in concrete structures. The method utilizes the frequency-dependent behavior of thin insulating cracks: low-frequency electrical currents are blocked by insulating cracks, whereas high-frequency currents can pass through thin cracks to probe the conducting bars. From various frequency-dependent electrical impedance tomography (EIT) images, we can show its advantage in terms of detecting both thin cracks with their thickness and bars. We perform numerical simulations and phantom experiments to support the feasibility of the proposed method.

Rehabilitative treatment of patients with ureterolithiasis using pulsed vacuum depression, pulsed low-frequency electric current, and radon therapy

The authors report results of the treatment of 60 patients with ureterolithiasis using a combination of pulsed vacuum depression (local vibrotherapy), low-frequency pulsed (alternating sinusoidal) current, radon water and radon baths. Clinical efficiency of combined therapy is estimated at 93.3%.

Method and apparatus for wave therapy

An oscillator ( 12 ) of a low-frequency therapeutic apparatus ( 10 ) is controlled by a frequency control device ( 18 ) to generate a plurality of frequencies selected according to the kind of a disease and these frequencies are delivered from the lowest in an ascending order at intervals of a specified time, and are injected into a human body at the same time or separately as low-frequency electric currents from a therapeutic electrode ( 14 ) and an inactive electrode ( 16 ), as electromagnetic waves from oscillating coils ( 14 ) and ( 14 A), and as acoustic waves from an acoustic wave oscillator ( 62 ) and a body sonic apparatus ( 64 ).

Moxibustion treatment of breech presentation.

Breech presentation was successfully corrected by stimulating acupuncture points with moxibustion or low-frequency electrical current. Only patients with breech pregnancies at the 28th week or later were entered into the study. With moxibustion treatment, the control group had a spontaneous correction rate of 165/224 (73.66%), and the treatment group had a correction rate of 123/133 (92.48%) (P<0.0001, x2 test). With low-frequency percutaneous electrical stimulation, the correction rate was 20/941 (83.87%) in the control group and 171/191 (89.52%) in the treatment group (P=0.094, x2 test). The controls in the moxibustion study did no exercises and received no external manipulation to correct breech presentation whereas those in the electrical stimulation study experienced both. Acupuncture stimulation, especially with moxibustion, is expected to serve as a safe and effective modality in the management of breech presentation in a clinical setting.

Imaging of particle shear migration with electrical impedance tomography

Electrical impedance tomography (EIT) is used to investigate the net migration of particles in a suspension undergoing pressure-driven flow through a tube at low Reynolds number. A low frequency electrical current is applied to the flowing suspension by two flush-mounted electrodes on the pipe wall to create a potential field which is sampled by other pairs of flush-mounted electrodes. A numerical inversion of the data, which takes into account the geometry and symmetry of the problem, gives the conductivity variation within the flow. An image of the suspension particle volume fraction in the tube is then formed using a relationship between the local conductivity and local suspension concentration. Consistent with particle shear migration of a concentrated suspension at low Reynolds number, the images from experimental data show a net migration of particles toward the centerline of the tube. The images of a 0.25 volume fraction suspension at the lowest Reynolds number examined compare favorably to an existing continuum theory of particle shear migration. Other images from experiments at higher, but still small Reynolds numbers, and at volume fractions of 0.25 and 0.40 are also presented. The particle migration measured with the relatively inexpensive EIT at the latter condition is in very good agreement with the particle distribution measured with magnetic resonance imaging by Hampton et al. [J. Rheol. 41, 621 (1997)].

The effect of electrical acupuncture-stimulation therapy using thermography and plasma endothelin (ET-1) levels in patients with progressive systemic sclerosis (PSS)

In all 11 patients with progressive systemic sclerosis (PSS; Barnett type I, 2; type II, 5; type III, 4 cases; male l; female 10 cases; 45.2±10.2 years-old), 6 cases of scleroderma spectrum disorders (SSD, male l; female 5 cases; 51.2±13.2 years-old) and 7 healthy controls (HC, male 1; female 6 cases; 43.1±8.4 years-old) were entered to be examined. The plasma endothelin-1 (ET-1) levels of PSS, SSD and HC were 1.98±0.69, 1.76±0.39 and 1.15±0.38 pg/ml, respectively. After the stimulation with the low frequency electrical current, electrical acupuncture, for unilateral side of hand/arm (30 min), the plasma ET-1 levels decreased in 10 cases of PSS treated (1.61±0.45 pg/ml), but no change of plasma serotonin levels. In 4 of 6 cases of SSD, plasma ET-1 levels increased (2.06±0.39 pg/ml), however, nitrate levels increased and serotonin decreased in 3 of 5 cases of SSD. In 6 cases of HC treated with the electrical acupuncture, the plasma ET-1 levels increased (1.72±0.58 pg/ml). Thermographically, 9 of 11 cases of PSS and 5 of 6 cases of SSD showed temporally temperature-elevation of hand/fingers not only in treated sides, but also in non treated sides, although none of 7 HC showed temperature-elevation of hands/fingers. The decrease in plasma ET-1 levels due to the electrical acupuncture was thought to induce the vasodilatation and elevate the surface temperature in patients with PSS. These results will provide an excellent basis to study the efficacy of electrical acupunctural stimulation.

Response of cytosolic calcium, cyclic AMP, and cyclic GMP in Dimethylsulfoxide‐differentiated HL‐60 cells to modulated low frequency electric currents

The action of interferential current (IFC), an amplitude-modulated 4000 kHz current used in therapeutic applications, upon intracellular calcium, adenosine 3′:5′-cyclic monophosphate (cAMP), and guanosine 3′:5′-cyclic monophosphate (cGMP) was investigated. Human promyelocytes (HL-60) were differentiated to granulocytes by dimethylsulfoxide (DMSO) treatment and exposed for 5 min at 25, 250, and 2500 μA/cm2 current density. No significant changes in cytosolic free calcium were detected as a function of modulation frequency of the IFC. However, intracellular cAMP reacted in a complex way to modulation frequency, resulting in stimulations and depressions within the range of frequencies studied (0–125 Hz). The “windows” of modulation frequency, where statistically significant increases or decreases in cAMP were noted, coincided with those published earlier for mouse fibroblasts. Cellular cGMP content was always lowered by IFC treatment. Furthermore, no significant influence of IFC current density upon the three second messengers was noted. These results, which also include data relating to treatment with sinusoidal 50 Hz current, contribute to a more detailed understanding of the primary biophysical mechanisms of signal transduction by time-varying electric fields. Bioelectromagnetics 19:452–458, 1998. © 1998 Wiley-Liss, Inc.

Response of cytosolic calcium, cyclic AMP, and cyclic GMP in Dimethylsulfoxide-differentiated HL-60 cells to modulated low frequency electric currents

The action of interferential current (IFC), an amplitude-modulated 4000 kHz current used in therapeutic applications, upon intracellular calcium, adenosine 3':5'-cyclic monophosphate (cAMP), and guanosine 3':5'-cyclic monophosphate (cGMP) was investigated. Human promyelocytes (HL-60) were differentiated to granulocytes by dimethylsulfoxide (DMSO) treatment and exposed for 5 min at 25, 250, and 2500 microA/cm2 current density. No significant changes in cytosolic free calcium were detected as a function of modulation frequency of the IFC. However, intracellular cAMP reacted in a complex way to modulation frequency, resulting in stimulations and depressions within the range of frequencies studied (0-125 Hz). The "windows" of modulation frequency, where statistically significant increases or decreases in cAMP were noted, coincided with those published earlier for mouse fibroblasts. Cellular cGMP content was always lowered by IFC treatment. Furthermore, no significant influence of IFC current density upon the three second messengers was noted. These results, which also include data relating to treatment with sinusoidal 50 Hz current, contribute to a more detailed understanding of the primary biophysical mechanisms of signal transduction by time-varying electric fields.

New experimental technique for detecting the effect of low‐frequency electric fields on enzyme structure

A new experimental approach has been developed to determine kinetic and thermodynamic parameters of the inactivation of an enzyme under labile conditions both with and without exposure to electrical currents as sources of perturbation. Studies were undertaken to investigate if low-frequency electric currents can accelerate the thermal inactivation of an enzyme through interactions with dipole moments in enzymatic molecules and through related mechanical stresses. The experiments were conducted with the enzyme acid phosphatase. The enzyme was exposed to a 50-Hz current at different densities (10 to 60 mA/cm2 rms) or to a sinusoidal or square-wave current at an average density of 3 mA/cm2 and frequencies from, respectively, 50 Hz to 20 kHz and 500 pulses per second (pps) to 50,000 pps. Positive-control experiments were performed in the presence of a stabilizer or a deactivator. The results indicate that the technique is sensitive to conformational changes that otherwise may be impossible to detect. However, exposure to electric currents under the experimental conditions described herein showed no effects of the currents.

Effects of alternating magnetic fields and low-frequency electric currents on human skin blood flow.

The influence of alternating magnetic fields on human skin blood flow was investigated. The hands of volunteers were fixed just above an induction heater and the regional skin blood flow of a fingertip was measured by a laser Doppler flowmeter. The hands were exposed to fields with flux densities of 16 mT, 32 mT and 48 mT at a frequency of 3·8 kHz. Two parameters of the laser Doppler blood flow recording were studied: the dynamic and DC components. The dynamic component did not show any particular changes following magnetic stimulation. The DC component showed a rapid decrease in blood flow in the first period after field-on at 48 mT and 32 mT. A pain sensation with muscle contraction was recognised (48 mT and 32 mT). The effect of electrical stimulation on skin blood flow was also investigated. The differences between the magnetic and electrical effects are discussed. The results suggest that the human body responds to magnetic stimulation with an escape reaction which results in an elevated vasoconstrictor tone. The change in microvascular blood flow recorded with the laser Doppler method can probably be explained by the influence of the eddy currents on the sensory receptors of the skin.

1969 Reevaluation of Lethal Electric Currents

Low-frequency electric currents of a few milliamperes flowing through the body cause muscular contractions. In the arm such an effect may make a subject unable to let go of a live conductor. The highest currents which 99.5 percent of men and 99.5 percent of women are able to let go have been shown to be 9 and 6 mA, respectively. Currents somewhat larger than this, in the range of 20 to 40 mA, passing across the chest may arrest respiration leading to asphyxia, unconsciousness, and even death. The most common cause of death in electric shock probably is ventricular fibrillation, a condition in which the circulation is arrested and death ensues very rapidly. An analysis of available experimental data indicates that body weight and shock duration are important factors in determining the maximum current not likely to cause ventricular fibrillation. Taking a weight of 50 kg as the average for a human victim it is suggested that the relationship between current shock duration is given by I = 116/√T, where I is the current in milliamperes and T is the time in seconds. It must be stressed that this has only been shown to be valid within the range of 8 ms to 5 seconds. Currents flowing through the nerve centers controlling respiration may cause respiratory inhibition, which sometimes persists for a long time after the current has been interrupted. Other effects produced by high currents, such as burning, etc., are not discussed in this paper.

ヒトの外側翼突筋の筋電図 Ｉ 下関へのハリ治療時のハリを電極とした誘導方法について

Patients with TMJ disfunction or toothache have been treated by Acupuncture theraphy at the Pain Clinic in Osaka Dental University.This Acupuncture theraphy is practiced by inserting the needle on the acupoint ST III (No.7) approximately 3540mm depth and stimulating with low frequency electric current. The acupoint ST III (No.7) is located in the center of the half-round area between the mandibular notch of the mandible and the malar arch.Authors took an interest of the possibility of locating of the needle into the lateral pterygoid muscle during Acupuncture therapy.And EMG recording of the lateral pterygoid muscle was tried through this needle as an electrode. EMG activity through the needle electrode was appeared during the protrusive movement of the mandible and the Jaw opening movement.And this EMG activity was an antagonistic realtionship with that of the posterior part of the temporal muscle during anterior-posterior and lateral mandibular movement.From these two facts, the EMG waves through the needle electrodes were proved to be the activity of the lateral pterygoid muscle.

Microcirculatory system in the wall of the rat small intestine after neuroreflex isolation

Electron microscopy was used to study the regenerating bone tissue in experimental resection of the diaphysis fragment of the rabbit radius under osteogenesis stimulation by means of pulsed low-frequency electric current. Proliferation and differentiation of fibroblasts and osteoblasts of the bone regenerating tissue were more active under electric stimulation. Hypertrophy and hyperplasia of cell organelles occurred earlier as compared with control. Cell secretion was found to be intensified, manifesting by output of greater amounts of collagen protein. As a result of changes listed, the newly formed bone tissue rapidly filled the defect between the fragments.

An investigation into the soundness of the rock underlying the Leigh Woods abutment of the Clifton Suspension Bridge

Special care has always been taken to ensure the general safety of the Clifton Suspension Bridge and to maintain its conditions. The bridge is nearly 110 years old and carries more traffic now than ever before. Its preservation as a monument to the engineering genius of Isambard Kingdom Brunei is vital. Over the years concern has been expressed as to whether the limestone rock upon which the bridge is founded on the Leigh Woods side of the gorge was as massive and sound as that on the Clifton side—although it must be emphasized that no manifestation of subsidence or foundation displacement has ever been discovered. This concern was sharpened a few years ago when certain buildings in the Bristol area were thought to be at risk due to the finding of solution cavities and thick clay-filled joints in the limestone in their locality. The massive character of the rock on the Clifton side is plain to see in a near vertical cliff 250 ft high but on the Leigh Woods side of the Gorge the surface is at a slope averaging about 40 degrees to the horizontal. Although outcrops are large, much of the slope is covered by soil debris and vegetation. An investigation into the strata underlying the Leigh Woods abutment was therefore commenced by putting down 4 drillholes, one at each corner of the abutment forming a square grid with approximately 95-ft sides. From these boreholes an electrical survey was carried out by passing very low frequency electric currents between electrodes lowered into the holes. Resistances were measured between the sides and diagonals of the square at increments of depth. Great importance was attached to the coring of the drill holes and a very high degree of recovery was achieved. The cores obtained were of hard, light and dark grey crystalline Carboniferous Limestone cut through with thin irregular calcite veins. Very thin bands of mudstone were also found. One band was 1 in thick but all others were thinner and, as no positive correlation between cores could be obtained, the bands were judged to be lenticular. The bands penetrated lay parallel to the dip which was confirmed as being approximately 30 degrees in an upstream direction. The overall impression gained from the four drillholes was of a very massive, sound rock formation. No cavities were penetrated except for some very small calcite filled vughs. The electrical survey detected an anomaly close to the surface and another, less well defined, at greater depth. The former seemed likely to be in a fairly central position immediately beneath the abutment. A fifth drillhole was therefore put down through the structure of the abutment into the underlying rock. This hole was again carefully cored and revealed that the abutment itself was hearted by well grouted sandstone plums. Below the abutment a breccia filled fissure was penetrated. This Triassic filling consisted of irregular blocks of limestone, sandstone and siltstone with a calcareous cement. Although a hard material and quite suitable as a foundation, it was considered a sufficient explanation for the upper anomaly. With the lower anomaly being so ill defined it would have been difficult and costly to investigate it by drilling further holes which would have had to be either horizontal or inclined. Many explanations for the anomaly were possible—it could be due to further breccia filling, to a comparatively more massive limestone or, more unlikely, to a cavity—but even the last explanation was considered acceptable bearing in mind its probable location some 75 ft below the abutment. The installation of monitoring devices in the drillholes to detect movement over a period had been allowed for but, in view of the generally satisfactory outcome of the investigations, this further work was not considered necessary.

Reevaluation of Lethal Electric Currents

Low-frequency electric currents of a few milliamperes flowing through the body cause muscular contractions. In the arm such an effect may make a subject unable to let go of a live conductor. The highest currents which 99.5 per cent of men and 99.5 percent of women are able to let go have been shown to be 9 and 6 mA, respectively. Currents somewhat larger than this, in the range of 20 to 40 mA, passing across the chest may arrest respiration leading to asphyxia, unconsciousness, and even death.