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PubMed2002

The effect of electrical dental equipment on a vagus nerve stimulator's function.

BACKGROUND: Dental patients who have epilepsy with pharmacologically refractory seizures may be treated with an implanted pulse generator that electrically stimulates the left vagus nerve. The pulse generator functions like a cardiac pacemaker. Some electrical dental devices have been shown to cause electromagnetic interference with the function of cardiac pacemakers. The potential effect of similar dental equipment on vagus nerve stimulators is unknown. METHODS: Common electrical dental devices were operated at maximum power settings in close proximity to a representative vagus nerve stimulator. The author assessed any interference of the dental devices with the nerve stimulator function by observing oscilloscope tracings. RESULTS: Under the conditions of this evaluation, none of the dental devices tested altered the function of the vagus nerve stimulator. CONCLUSIONS: Some commonly used electrical dental devices may be used in close proximity to patients who have implanted vagus nerve stimulators without adverse effects on the nerve stimulator function. CLINICAL IMPLICATIONS: Dentists and dental hygienists may encounter patients with implanted vagus nerve stimulators, and they need to be cognizant of developments in the treatment of epilepsy. Under the conditions of this study, use of common dental electrical devices did not alter the function of a vagus nerve stimulator. The findings of this study, however, should not be generalized to all types of electrical dental or medical devices, as a recent report indicates that treatment with diathermy devices is contraindicated for patients with implanted nerve stimulators.

Dental Amalgam↗

PubMedDate not supplied

Membrane fusion and deformation of red blood cells by electric fields.

Human red blood cells suspended in a slightly hypotonic solution of low electric conductivity were exposed to an inhomogeneous and alternating electric field (sine wave, 30 V peak-to-peak value, electrode distance 120 microns, 0.5 to MHz). Due to the dielectrophoretic effect the cells align parallel to the field lines under the formation of pearl chains. At high voltages (10 V amplitude) membrane fusion is observed between the adhered red blood cells in the pearl chains, whereby the chains become attached to the electrodes. In contrast to the pearl chains observed at voltages of up to 5 V amplitude the resulting fused and uniform aggregates which exhibit no recognisable individual cells under the light microscope, remain stable, even after the alternating electric field has been switched off or after haemolysis in response to osmotic shock. The fused aggregates are highly elastic. If the field strength of the applied alternating electric field is further increased they are stretched in the direction of the opposite electrode. Frequently, bridges are formed between the two electrodes. The uniform bridges remain stable for some time even in the absence of an electric field. The possibility of cell fusion and its initiation by electrical breakdown of the cell membranes are discussed.

Cell Aggregation↗

PubMed1976

[Risks attendant on the use of electrical equipment in anaesthesia and intensive care units].

The physical principles of electricity and types of electrical injuries are reviewed. The extent of such injuries depends on the strength of the current: ventricular fibrillations can be induced by a current of 10mA, and even of 10 muA if the current passes directly through the heart. The extent of electrothermal injuries depends on the duration of the current flow and the contact area. Indirect electrical injuries may arise from interferance with cardiac pacemakers or monitoring equipment. Risks attendant on the use of even the "safest" electrical apparatus are discussed, with special reference to the risks arising from interaction between, e.g., high frequency diathermy and monitoring equipment or domestic appliances (beside lamp, razor) and monitoring or electrical therapeutic equipment. A number of safety measures to minimize the risk of electrical injuries are discussed.

Anesthesiology↗

PubMed1975

[Electrical injuries in childhood (author's transl)].

11 children were admitted with electrical injuries to the Department of Paediatrics, University of Graz, over the 10-year period 1965 to 1974. The electricity was of low voltage in the case of 9 of these children, who were injured whilst playing with plug sockets of defective cables and of high voltage in 4 case. 1 child was stuck by lightning. Cessation of respiration occurred in 4 of the patients and was successfully counteracted in all cases by prompt mouth-to-mouth breathing. 7 children were still shocked on admission. All children showed the characteristic skin lesions of electrical injury (current marks of linear, round or spidery form). The boy injured by high voltage electricity received extensive burns, in addition. The modes of electrical injury in childhood, the various forms of the resultant lesions, especially of the skin and the treatment of electrical burns are discussed.

Adolescent↗

PubMed2005

[Electrical defibrillation and cardioversion].

Defibrillation and cardioversion are techniques in which a short electric impulse is administered to the heart in order to restore its normal rhythm. During cardioversion electric impulse is synchronized to the QRS on electrocardiogram. During defibrillation electric current passes through the heart in any phase of electric heart cycle. This mode of treatment is rather new - Lown et al. started to use it in a clinical practice in 1962. During defibrillation or cardioversion electric current goes from negative to positive electrode of defibrillator and passes the heart on its way. This induces transmembrane potential in myocardium cells and results in synchronic depolarization of all myocardium. The pathophysiology of defibrillation is explained by critical mass hypothesis as well as the upper limit of vulnerability hypothesis. The success of defibrillation depends on many factors, such as the location and size of electrodes, the type of defibrillator, the morphology of electric impulse, transthoracic impedance, the type and duration of arrhythmia. This procedure can be performed only on unconscious patient. The possible complications of the procedure can be disturbances in heart rhythm and conduction, the changes in arterial blood pressure, the damage to the myocardium, embolia, pulmonary edema and others. This article describes the mechanism of action of defibrillation and cardioversion, indications for this procedure, the technique and methods of defibrillation and cardioversion, the factors, responsible for the efficacy of the procedure and possible complications of defibrillation.

Defibrillators↗

PubMed1990

Electrical stimulation of bone and its implications for endosseous dental implantation.

Applied electrical potentials can alter cellular movement, stimulate production or destruction of cells, and change the chemical concentration and composition of both soft tissue and bone. These actions vary depending on the microamperage and duration of the applied current and whether it is continuous or pulsed, the type of metallic electrode, and the types of cells or tissues involved. Relative to skeletal effects, researchers have accumulated data from bone cell cultures, embryonic and adult animal bone, and human clinical studies. This article reviews the historical use of electric current for fracture healing, the piezoelectric effect found in tissues, and the possible deleterious effects of electrical stimulation. The types of electric current presently used for treating extremity fractures and reports where electric current has been used on tissues in the oral cavity are discussed. Alternate sources of energy to stimulate bone and possible implications for use of electrical stimulation to augment attachment of endosseous dental implants are also included.

Bone Regeneration↗

PubMed1987

External electrical tinnitus suppression: a review.

Our experience with transcutaneous electrical stimulation for tinnitus suppression has been with the Theraband Headset from Audimax Inc. The purpose of this article is to review the highlights of the patients who exhibited tinnitus suppression and/or tinnitus control, and to provide an update of our results and techniques using external electrical stimulation with prolonged stimulation (stage IV). Patient selection is considered critical to the success of external electrical stimulation for tinnitus suppression. The key elements include the clinical finding of a peripheral site of lesion of the tinnitus; positive maskability of the symptom of tinnitus; absence of active ear disease; absence of a vestibular asymmetry; and absence or minimal evidence of dysfunction of the central auditory system. The protocol described for patient selection allows for tinnitus identification, the differentiation of clinical tinnitus types, and the clinical application of the concept of the dynamic range of electrical tinnitus suppression. External electrical tinnitus suppression is believed effective in a limited number of patients clinically identified as having a tinnitus site of lesion primarily peripheral in location and cochlear in type. The present device is not commercially available at this time. Both specific and general suggestions are proposed for the standardization of methods of reporting results of electrical tinnitus suppression and tinnitus control.

Electric Stimulation Therapy↗

PubMed1996

Investigation of deaths related to electrical injury.

Even though the use of electricity is an integral part of our lives, the number of accidents and deaths related to electricity is on the decline. This is due to increased awareness of electrical hazards and, in large part, to increased inclusion of safety mechanisms by manufacturers. However rare, electrical injury and related death can present a complicated case in the emergency department and for death investigators. Sometimes the circumstances of the physical scene are unclear because of intentional or accidental alterations or the investigator's inability to reconstruct events leading to the injury. This may hinder the initial clinical assessment. We present cases of typical and atypical deaths from electrical injury and review clinical and investigative procedures to assist in the treatment of patients with electrical injuries.

Accidents↗

PubMed1999

Mortality patterns among electrical workers employed in the U.S. construction industry, 1982-1987.

BACKGROUND: Studies of electrical workers in the utility and manufacturing industries have reported excess site-specific cancer. No previous studies of electrical workers in the construction industry have been conducted. METHODS: Our study evaluated the mortality patterns of 31,068 U.S. members of the International Brotherhood of Electrical Workers who primarily worked in the construction industry and died 1982-1987. RESULTS: Comparison to the U.S. population by using the NIOSH life table showed significantly elevated proportionate mortality for many causes. Excess mortality for leukemia (proportionate mortality ratio (PMR)=115) and brain tumors (PMR=136) is similar to reports of electrical workers with occupational exposure to electric and magnetic fields in the electric utility or manufacturing industry. Excess deaths due to melanoma skin cancer (PMR=123) are consistent with findings of other PCB-exposed workers. A significantly elevated PMR was observed for the diseases caused by asbestos: lung cancer (PMR=117), asbestosis (PMR=247), and malignant mesothelioma (PMR=356) and from fatal injuries, particularly electrocutions (PMR=1180). The findings of statistically significant excess deaths for prostate cancer (PMR=107), musculoskeletal disease (PMR=130), suicide (PMR=113), and disorders of the blood-forming organs (PMR=141) were unexpected. CONCLUSIONS: Results suggest that more detailed investigations of occupational risk factors and evaluation of preventive practices are needed to prevent excess mortality in this hazardous occupation. Am. J. Ind. Med. 36:630-637, 1999. Published 1999 Wiley-Liss, Inc.

Adult↗

PubMed1999

Capillary zone electrophoresis with electroosmotic flow controlled by external radial electric field.

A new way of regulation of electroosmotic flow (EOF) in capillary zone electrophoresis (CZE) by external electric field has been developed. A set of three high-voltage power supplies is used to form a radial electric field across the capillary wall. One power supply is applied in the usual way as a driving force of CZE and EOF to the ends of the inner capillary compartment dipped into the electrode vessels and filled with background electrolyte. Two power supplies are connected to the ends of the outer low-conductivity coating of the capillary which is formed by the dispersion of copolymer of aniline and p-phenylenediamine in polystyrene matrix. The difference between electric potentials on the outer capillary surface and inside the capillary determines the voltage of radial electric field across the capillary wall and affects the electrokinetic potential at the solid-liquid interface inside the capillary. The effect of magnitude and polarity of external radial electric field on the flow rate of EOF, on the migration times of charged analytes and on the separation efficiency and resolution of CZE separations of synthetic oligopeptides, diglycine, triglycine and octapeptide fragments of human insulin was evaluated. Through the EOF control by external electric field the dynamic effective length of the capillary was obtained and the speed of analysis and resolution of CZE separations of peptide analytes could be optimized.

Electric Conductivity↗

PubMed2000

Electrical stimulation for faecal incontinence in adults.

BACKGROUND: Faecal incontinence is a particularly embarrassing and distressing condition with significant medical, social and economic implications. Electrical stimulation has been used with apparent success in the treatment of faecal incontinence. However, standards of treatment are still lacking and the magnitude of alleged benefits has yet to be established. OBJECTIVES: To determine the effects of electrical stimulation for the treatment of faecal incontinence in adults. SEARCH STRATEGY: We searched the Cochrane Incontinence Group trials register, the Cochrane Controlled Trials Register, Medline, Embase and reference lists of potentially eligible articles up to November 1999. Date of the most recent searches: November 1999. SELECTION CRITERIA: All randomised or quasi-randomised trials evaluating electrical stimulation in adults with faecal incontinence. DATA COLLECTION AND ANALYSIS: Three reviewers assessed the methodological quality of potentially eligible trials and two reviewers independently extracted data from the included trial. A wide range of outcome measures were considered. MAIN RESULTS: Only one eligible trial with 40 participants was identified. It was a randomised trial, but it suffered from methodological drawbacks and did not follow up patients beyond the end of the trial period. Findings from this trial suggest that electrical stimulation with anal biofeedback and exercises provides more short-term benefits than vaginal biofeedback and exercises for women with obstetric-related faecal incontinence. No further conclusions could be drawn from the data available. REVIEWER'S CONCLUSIONS: At present, there are insufficient data to allow reliable conclusions to be drawn on the effects of electrical stimulation in the management of faecal incontinence. There is a suggestion that electrical stimulation may have a therapeutic effect, but this is not certain. Larger, more generalisable trials are needed.

Adult↗

PubMed2002

Electrical cardioversion for atrial fibrillation and flutter.

BACKGROUND: Atrial fibrillation increases the risk of stroke, increases the risk of cognitive impairment, and adversely affects cardiovascular haemodynamics. Electrical cardioversion for atrial fibrillation has been in use since the 1960s; the rationale is that restoration of sinus rhythm improves cardiovascular haemodynamics, reduces the risk of stroke, and obviates the need for long-term anticoagulation. OBJECTIVES: To assess the effects of electrical cardioversion of atrial fibrillation or atrial flutter on the annual risk of thromboembolic events, strokes and mortality (primary outcomes measures), the rate of cognitive decline, quality of life, the use of anticoagulants and the risk of re-hospitalisation (secondary outcome measures) in adults (>18 years) with acute, paroxysmal or sustained atrial fibrillation or atrial flutter, of any duration and any aetiology. SEARCH STRATEGY: One reviewer searched the Cochrane Controlled Clinical Trials Register (2000 Issue 4), MEDLINE (1966 to December 2000), EMBASE (1980 to December 2000), CINAHL (1982 to November 2000) and proceedings of the American College of Cardiology (published in the Journal of the American College of Cardiology 1983 to 2000). Reference lists of articles were searched. Personal contact was made with experts in the field. A second reviewer handsearched proceedings of the British Cardiac Society (published in British Heart Journal (1980 to 1995) and in Heart (1995 to May 2001); proceedings of the European Congress of Cardiology and meetings of the Joint Working Groups of the European Society of Cardiology (published in European Heart Journal 1983-2000); scientific sessions of the American Heart Association (published in Circulation 1990-2000). SELECTION CRITERIA: Randomised controlled trial or controlled clinical trials of electrical cardioversion plus 'usual care' versus 'usual care' only, where 'usual care' included any combination of the following: anticoagulants, antiplatelet drugs and drugs for 'rate control', in adults (>18 years) with acute, paroxysmal or sustained atrial fibrillation or atrial flutter, of any duration and any aetiology. DATA COLLECTION AND ANALYSIS: It was planned to extract study data onto data extraction forms. The planned analysis was by the statistical package in RevMan. MAIN RESULTS: No completed randomised trials or controlled clinical trials of electrical cardioversion were found. Two ongoing trials were identified. REVIEWER'S CONCLUSIONS: There were no data from completed randomised controlled trials or controlled clinical trials to either support or refute the use of electrical cardioversion for atrial fibrillation. Randomised trials of electrical cardioversion are required.

Adult↗

PubMed2003

Anatomy and motor pathways of the electric organ of skates.

The electric organ of skates is a paired structure within the tail consisting of two longitudinal columns of electrocytes contained within the lateral musculature on each side of the vertebral column. The electrocytes develop from hypaxial skeletal muscle fibers, and, depending upon the species, are generally classified as either cup-shaped or disc-shaped. The disc-shaped electrocytes are considered to be the more derived type. Regardless of the morphology of the electrocyte, the electric organ discharge of all skates is characterized as a weak asynchronous and long-lasting signal. Although recent behavioral investigations have revealed a communicative function for the electric organ, details as to which specific behaviors utilize this motor system remain uncertain. The electric organ is innervated by segmental motor nerves that branch from the ventral root of caudal spinal nerves at all levels of the electric organ. The cells of origin of the electromotor nerves, or electromotoneurons (EMNs), are large multipolar neurons with extensive dendrites located within the ventral gray matter of the spinal cord. The EMNs are uniformly distributed among the somatic motoneurons at levels corresponding to the rostrocaudal extent of the electric organ, and therefore do not form a discrete nucleus. The medullary command nucleus is comprised of neurons located within the nucleus raphe magnus, and forms a descending spinal pathway to the EMNs.

Animals↗

PubMed2002

Electrical stimulation as an adjunct to spinal fusion: a meta-analysis of controlled clinical trials.

This study was a meta-analysis to examine whether electrical stimulation has a specific effect on spinal fusion. Little evidence exists on the efficacy of electrical stimulation for improving fusion rate of spinal fusion surgery. Using MEDLINE (1966-2000) and EMBASE (1985-1999), a search for articles was carried out using the Medical Subject Headings: (1) electric stimulation or electromagnetic fields, (2) spinal fusion, (3) controlled or clinical trial, and (4) human. Data were extracted from all the hit articles and additionally collected from appropriate journal lists. A total of five randomized controlled trials (RCT) on bones assessing healing of spinal fusion were identified and scored on methodological quality. All the identified studies reported positive findings, but the quality score of each trial showed wide flaws. Because of relatively homogenous subjects who had spine fusion and radiographic assessment from these studies, pooling of the data was able to be performed. Excluding one trial with the lowest score, the combined results of four trials, whose major endpoints were the success rate of the fusion, revealed a statistically significant effect of electrical stimulation with various techniques, but the selected trials still showed wide variation in view of stimulation modalities and treatment protocol. The pooled result of the studies in this review revealed the efficacy of electrical stimulation based on proved methodological quality. As problems on therapeutic modality and protocol remain, there is a further need for improvement in design to constitute acceptable proof and to establish treatment programs that better demonstrate electrical stimulation effects on spinal fusion.

Combined Modality Therapy↗

PubMed1980

Cardiovascular response of rats exposed to 60-Hz electric fields.

Recently, it has been reported that exposure to high-strength electric fields can influence electrocardiogram (ECG) patterns, heart rates, and blood pressures in various species of animals. Our studies were designed to evaluate these reported effects and to help clarify some of the disagreement present in the literature. Various cardiovascular variables were measured in Sprague-Dawley rats exposed or sham-exposed to 60-Hz electric fields at 80 or 100 kV/m for periods up to four months. No significant differences in heart rates, ECG patterns, blood pressures, or vascular reactivity were observed between exposed and sham-exposed rats after 8 hours, 40 hours, 1 month, or 4 months of exposure. Blood pressure and heart rate measurements, made during exposure to a 100-kV/m electric field for one hour, revealed no significant differences between exposed and sham-exposed groups. In addition, physiologic reserve capacity, measured in rats subjected to low temperature after exposure to 100 kV/m for one month, showed that electric-field exposure had no significant effect on physiological response to cold stress. Our studies cannot be directly compared to the work of other investigators because of differences in animal species and electric-field characteristics. However, our failure to detect any cardiovascular changes may have been the result of 1) eliminating secondary field effects such as shocks, audible noise, corona, and ozone; 2) minimizing steady-state micro-currents between the mouth of the animal and watering devices; and 3) minimizing electric-field-induced vibration of the electrodes and animal cages.

Animals↗

PubMed1986

Response of sensory receptors of the cat's hindlimb to a transient, step-function DC electric field.

There are two possible mechanisms of effects of large electric fields on animals, one caused by the electric field at the body surface and the other caused by the electric current induced inside the body. The purpose of the present experiments was to investigate the former possibility by recording action potentials from afferent fibers innervating various sensory receptors in the cat's hindlimb. Cat hairs were attracted to the upper electrode when exposed to DC electric fields of 180 kV/m or greater, and action potentials were evoked in the afferent fibers innervating G1, G2, and down hair receptors. No action potentials were evoked in afferent fibers innervating type I, type II, field receptors, muscle spindles, or joint receptors. These results indicate that a strong DC electric field induced movement of the hairs, eventually evoked excitation of the hair receptors, but that other receptors located under the skin were not influenced by electric field exposure.

Afferent Pathways↗

PubMed1995

Membrane potential perturbations induced in tissue cells by pulsed electric fields.

Pulsed electric fields directly influence the electrophysiology of tissue cells by transiently perturbing their transmembrane potential. To determine the magnitude and time course of this interaction, electrotonic cable theory was used to calculate the membrane potential perturbations induced in tissue cells by a spatially uniform, pulsed electric field. Analytic solutions were obtained that predict shifts in membrane potential along the length of cells as a function of time in response to an electrical pulse. For elongated tissue cells, or groups of tissue cells that are coupled electrotonically by gap junctions, significant hyperpolarizations and depolarizations can result from millisecond applications of electric fields with strengths on the order of 10-100 mV/cm. The results illustrate the importance of considering cellular cable parameters in assessing the effects of transient electric fields on biological systems, as well as in predicting the efficacy of pulsed electric fields in medical treatments.

Animals↗

PubMed1982

Gene transfer into mouse lyoma cells by electroporation in high electric fields.

Electric impulses (8 kV/cm, 5 microseconds) were found to increase greatly the uptake of DNA into cells. When linear or circular plasmid DNA containing the herpes simplex thymidine kinase (TK) gene is added to a suspension of mouse L cells deficient in the TK gene and the cells are then exposed to electric fields, stable transformants are formed that survive in the HAT selection medium. At 20 degrees C after the application of three successive electric impulses followed by 10 min to allow DNA entry there result 95 (+/- 3) transformants per 10(6) cells and per 1.2 micrograms DNA. Compared with biochemical techniques, the electric field method of gene transfer is very simple, easily applicable, and very efficient. Because the mechanism of DNA transport through cell membranes is not known, a simple physical model for the enhanced DNA penetration into cells in high electric fields is proposed. According to this ' electroporation model' the interaction of the external electric field with the lipid dipoles of a pore configuration induces and stabilizes the permeation sites and thus enhances cross membrane transport.

Animals↗