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[High voltage accidents, characteristics and treatment].

High-voltage injuries cause localised entrance and exit burns, extensive arc, flame and flash burns and, even more dangerous, necrosis of the underlying muscles on the pathway of the current through the body. Therefore it should be recognized that the ensuing disease is more like a crush injury than a thermal burn. The extent of injury cannot be judged by the percentage and depth of the skin burn. Diagnostic fasciotomies, radical debridement, and in many cases early amputation are necessary to prevent life-threatening complications. Over a period of 10 years, 43 patients with high-voltage injuries have been treated at the Hamburg Burn Center, 36 of them in primary care. Common causes of injury were accidents in railway areas (28%), using portable aluminium ladders near overhead power lines (9.3%), and working on electrical equipment (30.2%). Six of the primary care patients died (16.6%), and 34.9% had an amputation of one or more extremities. Nearly all patients underwent several debridement and split-skin graft procedures. In 30% of cases additional free and pedicled flaps were needed to cover soft tissue defects. Ten patients (23.3%) sustained fractures and other injuries from falls, seven (16.3%) of them severe polytrauma. Initial cardiac arrhythmics were diagnosed in 16.6% of the primarily treated patients. Thirty per cent of our patients had neurological complications such as peripheral paresis, tetraplegia and paraplegia, 20.7% of these caused solely by the electric current.

Adolescent↗

Implantable defibrillators impedance measurement using pacing pulses versus shock delivery with intact and modified high voltage lead system.

At present the only method for measuring the high voltage system lead impedance in patients with an ICD is to deliver a low energy test shock. This is painful, requires sedation, and carries a risk of ventricular fibrillation induction. We sought to assess the shock lead and electrode function by calculating IMP using low voltage pacing pulses, and compared it to the measured impedance of a shock through the same lead. This was performed in both an intact and a modified lead system in order to mimic common clinical scenarios that alter lead system IMP (e.g., lead fracture). In an anesthesized canine model (n = 12) a standard (S) transvenous defibrillation lead (TDL), a modified (M) TDL (two-thirds of coil covered with heat-shrunk tubing), an active can (AC), and a M epicardial patch (EP) (two of four coils were disconnected) were used. Three configurations (C) were tested: C1:S/TDL-->AC, C2:M/TDL-->AC, and C3:M/TDL-->MEP. A measured IMP was obtained by an ICD using a 5-J shock as control. IMP was calculated using a 5-J shock, pacing pulses of 10-, 5-, 2-, and 1-V amplitude, as well as from a square wave drive train of low amplitude/high frequency signals (1 and 0.2 V, at 10 kHz) in all Cs. Ohm's law (V = IR) was utilized for measuring calculated IMP. As the surface area of the high voltage lead system decreased, the mean measured IMP (control) increased from C 1 to 3 (63 +/- 10, 95 +/- 4, and 127 +/- 20 omega, respectively). The correlation of calculated IMP from all Cs to measured impedance (control) remained high throughout the IMP range (range of correlation coefficient (r): 0.921-0.981). Calculated IMP using delivery of pacing pulses is highly correlated to IMP measured during shock delivery. This correlation remains high over a clinically significant range of high voltage lead system IMP changes. This study suggests that pacing pulses can be used to predict the IMP changes in the high voltage lead system which may occur clinically, reducing the need to deliver a shock for IMP measurement.

Animals↗

[Study on the abnormal gene expression of inducible nitric oxide synthase (iNOS) in rabbit myocardium after high voltage electrical injury].

OBJECTIVE: To elucidate the effects of high voltage electrical injury on the mRNA expression of iNOS And endothelin-1 (ET-1) in rabbit myocardium. METHODS: Rabbits inflicted by high voltage electrical injury were employed as the model. Reverse transcription PCR (RT-PCR) and serum enzyme measurement were used in the detection of the expression levels of iNOS mRNA and ET-1 mRNA of rabbit myocardial tissue and plasma creatine kinase (CK) content. RESULTS: The expression of iNOS mRNA in rabbit myocardial tissue after high voltage electrical injury increased at 6 to 8 postburn hours (PBH) and decreased thereafter. The plasma contents of CK and ET-1 mRNA reached their peak values at 2 PBH. CONCLUSION: The increase of iNOS mRNA might protect myocardial tissue from electrical injury.

Animals↗

The effects of cholinergic drugs on rat neocortical high-voltage spindles in ketanserin-treated rats.

To investigate the roles of the cholinergic system and 5-HT2 receptors in the modulation of thalamocortical oscillations, we studied the effects of systemic (s.c.) administration of anticholinesterases (physostigmine, tetrahydroaminoacridine) and muscarinic acetylcholine receptor agonists (pilocarpine, oxotremorine) on spontaneous thalamically generated rhythmic neocortical high-voltage spindles in adult rats pretreated with either saline or ketanserin, a 5-HT2 receptor antagonist. Ketanserin at 20.0 mg/kg increased the number of high-voltage spindles. In saline-treated rats, tetrahydroaminoacridine 3.0 and 9.0 mg/kg was able to decrease high-voltage spindles, whereas in ketanserin 20.0 mg/kg-treated rats only the highest dose of tetrahydroaminoacridine (9.0 mg/kg) decreased high-voltage spindles. Both doses of physostigmine, 0.12 and 0.36 mg/kg, decreased high-voltage spindles in both saline and ketanserin 20.0 mg/kg-treated rats. Lower doses of tetrahydroaminoacridine (1.0 mg/kg) and physostigmine (0.06 mg/kg) were ineffective in both saline- and ketanserin 20.0 mg/kg-treated rats. Pilocarpine 3.0 mg/kg and oxotremorine 0.1 and 0.9 mg/kg decreased high-voltage spindles in saline-treated rats. However, in rats treated with ketanserin 20.0 mg/kg, only the lower doses of pilocarpine (0.3 and 1.0 mg/kg) and oxotremorine (0.03 mg/kg) were able to decrease the high-voltage spindles. The results suggest that activation of the cholinergic system and activation of 5-HT2 receptors have additive effects in the suppression of thalamocortical oscillations and related neocortical high-voltage spindles in rats, thus maintaining effective information processing in thalamocortical networks.

Animals↗

Modulation of rat neocortical high-voltage spindle activity by 5-HT1/5-HT2 receptor subtype specific drugs.

To investigate the role of serotonin (5-hydroxytryptamine; 5-HT) receptors in the modulation of rat thalamocortical oscillations, we studied the effects of 5-HT1/5-HT2 receptor subtype specific drugs on neocortical high-voltage spindle activity in adult male rats. A 5-HT1A receptor agonist, 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) (0.03, 0.1, 0.3 and 1.0 mg/kg s.c.), had no effect on neocortical high-voltage spindle activity. Furthermore, a mixed 5-HT1/5-HT2 receptor antagonist, methysergide (1.0, 5.0 and 15.0 mg/kg i.p.), had no effect, whereas a non-specific mixed 5-HT1/5-HT2 receptor antagonist, methiothepin (0.2, 1.0 and 5.0 mg/kg i.p.), significantly increased neocortical high-voltage spindles. Of the 5-HT2 receptor antagonists, ritanserin (0.1, 1.0 and 5.0 mg/kg s.c.) had no effect, whereas ketanserin (1.0, 5.0 and 20.0 mg/kg s.c.) increased neocortical high-voltage spindles, but only at the highest dose used. A 5-HT2 receptor agonist, 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI) (0.5, 1.0 and 2.0 mg/kg s.c.), at the two highest doses significantly decreased neocortical high-voltage spindle activity, and this effect was blocked by the 5-HT2 receptor antagonists, ketanserin (1.0, 5.0 and 20.0 mg/kg s.c.) and ritanserin (1.0 and 5.0 mg/kg s.c.), as well as by methiothepin (0.2, 1.0 and 5.0 mg/kg i.p.) and methysergide (1.0, 5.0 and 15.0 mg/kg i.p.). Furthermore, unilateral intrathalamic infusions, but not intrahippocampal control infusions, of DOI (10 and 50 micrograms/1.0 microliters/rat) decreased neocortical high-voltage spindle activity and systemic administration of ketanserin (20.0 mg/kg s.c.) completely blocked this effect. The present results suggest that (1) the serotonergic system modulates rat thalamocortical oscillations as measured by neocortical high-voltage spindle activity, (2) activation of 5-HT2 receptors, possibly located in the thalamus, with a specific 5-HT2 receptor agonist, DOI, causes a reduction in rat neocortical high-voltage spindle activity.

8-Hydroxy-2-(di-n-propylamino)tetralin↗

Optimizing parameters for correlative immunogold localization by video-enhanced light microscopy, high-voltage transmission electron microscopy, and field emission scanning electron microscopy.

Correlative video-enhanced light microscopy, high-voltage transmission electron microscopy, and low-voltage high resolution scanning electron microscopy were used to examine the binding of colloidal gold-labeled fibrinogen to platelet surfaces. Optimal conditions for the detection of large (18 nm) and small (3 nm) gold particles are described.

Blood Platelets↗

Suppression of neocortical high-voltage spindles by nicotinic acetylcholine and 5-HT2 receptor stimulation.

To investigate the roles of the nicotinic acetylcholine receptor and the serotonin (5-hydroxytryptamine; 5-HT) subtype 2 receptor in the modulation of rat thalamocortical oscillations, the effects of systemic (s.c.) administration of nicotine, a nicotinic acetylcholine receptor agonist, and 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI), a 5-HT2 receptor agonist, on neocortical high-voltage spindle activity occurring during quiet waking-immobility behavior in aged (28 months of age) and adult (7 months of age) rats were studied. Nicotine 0.1 and 0.3 mg/kg alleviated the age-related increase of neocortical high-voltage spindles, whereas in adult rats only nicotine 0.3 mg/kg was effective. DOI 0.3, 1.0 and 2.0 mg/kg suppressed high-voltage spindles in both aged and adult rats. In aged rats, a combination of subthreshold doses of nicotine (0.03 mg/kg) and DOI (0.1 mg/kg) decreased neocortical high-voltage spindles, whereas in adult rats two different subthreshold dose combinations (nicotine 0.03 or 0.1 mg/kg+DOI 0.1 mg/kg) had no effect. p-Chlorophenylalanine (400 mg/kg/day i.p. for 3 consecutive days) treatment decreased brain serotonin concentration (> 80% reduction), but did not affect high-voltage spindles. However, in both aged and adult rats, p-chlorophenylalanine treatment blocked the decrease in high-voltage spindle activity produced by DOI 0.3 mg/kg, though not the decrease produced by higher doses of DOI (1.0 and 2.0 mg/kg). It is important that, in adult rats, p-chlorophenylalanine treatment was able to abolish the decrease in high-voltage spindle activity seen after a relatively high dose of nicotine (0.3 mg/kg). The results suggest that nicotinic acetylcholine and 5-HT2 receptors may act in concert to suppress neocortical high-voltage spindling in rats, and that intact brain serotonergic systems may be important for some of the therapeutic effects of nicotine.

Age Factors↗

Safety aspects for public access defibrillation using automated external defibrillators near high-voltage power lines.

BACKGROUND: Automated external defibrillators (AEDs) must combine easy operability and high-quality diagnosis even under unfavorable conditions. This study determined the influence of electromagnetic interference caused by high-voltage power lines with 16.7-Hz alternating current on the quality of AEDs' rhythm analysis. METHODS: Two AEDs frequently used in Austria were tested near high-voltage power lines (15 kV or 110 kV, alternating current with 16.7 Hz). The defibrillation electrodes were attached either to a proband with true sinus rhythm or to a resuscitation dummy with generated sinus rhythm, ventricular fibrillation, ventricular tachycardia or asystole. RESULTS: Electromagnetic interference was much more prominent in a human's than in a dummy's electrocardiogram and depended on the position of the electrodes and cables in relation to the power line. Near high-voltage power lines the AEDs showed a significant operational fault. One AED interpreted the interference as a motion artifact, even when underlying rhythms were clearly detectable. The other AED interpreted 16.7-Hz oscillation as ventricular fibrillation with consequent shock advice when no underlying rhythm was detected. CONCLUSION: The tested AEDs neither filter nor recognize a technical interference of 16.7 Hz caused by 15-kV power lines above railway tracks or 110-kV overland power lines, as run by railway companies in Austria, Germany, Norway, Sweden and Switzerland. These failures in AEDs' algorithms for rhythm analysis may cause substantial harm to patients undergoing public access defibrillation. The proper function of AEDs needs to be reconsidered to guarantee patients' safety near high-voltage power lines.

Algorithms↗

Separation of large DNA molecules with high voltage pulsed field gel electrophoresis.

We have developed two high voltage (3 kV and 10 kV) high speed pulsed field gel electrophoresis systems for the separation of DNA as large as 460 kbp. These systems enable us to combine the rapid speed of high voltages and the separation power of pulsed field electrophoresis to achieve high resolution and short run durations. We found that large DNA fragments can be separated at voltage gradients much higher than commonly used. Yeast chromosomes as large as 460 kbp can be separated in 4 h at 20 V/cm and 1-50 kbp DNA can be rapidly separated in 30 min at 55 V/cm. This is 25 times faster in mobility for the separation of relatively small DNA fragments (< 50 kbp). We have also found an inverse relationship between the voltage applied and the size separation limit at that particular voltage gradient (55 V/cm limits the separation to 50 kbp while 20 V/cm can separate up to 460 kbp). Depending on the size range, DNA can be separated 8- to 25-fold faster and with better resolution than existing electrophoretic systems.

Adenoviruses, Human↗

Bovine olfactory and nasal respiratory epithelium surfaces. High-voltage and scanning electron microscopy, and cryo-ultramicrotomy.

High-voltage transmission electron microscopy and cryo-ultramicrotomy together with scanning electron microscopy and some conventional transmission electron microscopy of ultrathin sections have been applied to the mucous surfaces of bovine olfactory and respiratory epithelia. Distal segments of olfactory cilia tend to run in parallel and could be followed over distances up to about 30 micrometer using high-voltage electron microscopy. This technique and scanning electron microscopy showed that on average 12--13 of such cilia could be observed per nerve ending. After correction for obscured cilia this number becomes about 17. High-voltage micrographs and micrographs made from sections prepared with a cryo-ultramicrotome showed the presence of electron-lucent pockets inside the olfactory mucus. The latter technique also showed that the mucus itself is not fibrous, but rather a continuum varying in electron density. The mucus layer contains various granular structures. Ciliary and microvillar membranes appear thicker with cryo-ultramicrotomy than when the sections are prepared with conventional techniques. The cores of the axonemal microtubules in olfactory as well as in respiratory cilia are darkly stained with this technique. Vesicles present inside the nerve endings are also darkly stained. Dimensions and some other numerical values of interest in olfaction are presented.

Animals↗

Alpha 1-adrenoceptor antagonist decreases alpha 2-adrenoceptor antagonist-induced high voltage spindle suppression in adult and aged rats.

The present experiments were undertaken to study whether blockade of alpha 1-adrenoceptors would prevent the high-voltage spindle suppressing effect of atipamezole, an alpha 2-adrenoceptor antagonist. In adult rats, an alpha 1-adrenoceptor antagonist, prazosin, increased dose dependently the high voltage spindles in saline and atipamezole-pretreated rats. In addition, in aged rats prazosin blocked the high-voltage spindle suppressing action of atipamezole. Prazosin produced a smaller increase in high-voltage spindle values in aged than in adult rats. According to the present results, alpha 2-adrenoceptor antagonists may suppress high-voltage spindles indirectly by activating alpha 1-adrenoceptors in young and aged rats.

Adrenergic alpha-Agonists↗

Identification and characterization of populations living near high-voltage transmission lines: a pilot study.

Populations living close to high-voltage transmission lines often have residential magnetic field exposures in excess of 1 microT, and sometimes over 2 microT. Yet, populations studied in most epidemiologic investigations of the association between residential magnetic field exposure and cancer typically have exposures below 1 microT and frequently below 0.5 microT. To improve statistical power and precision, it would be useful to compare high exposure populations with low exposure populations rather than only studying small differences within low exposure populations. Toward this end, we have developed an automated method for identifying populations living near high-voltage transmission lines. These populations likely have more highly exposed individuals than the population at large. The method uses a geographic information system (GIS) to superimpose digitized transmission line locations on U.S. Census block location data and then extract relevant demographic data. Analysis of data from a pilot study of the populations residing within 100 m of a 29-km segment of one 230-kV line in New Jersey shows that when compared to populations in the surrounding census blocks farther than 100 m from this line, those populations close to the line have similar demographics but differ in terms of perceived housing value variables. We believe that the approach we have developed will enable investigators to rapidly identify and characterize populations living near high-voltage transmission lines on a statewide basis for considering the impact of exposures and for public policy and that these populations also can be used for epidemiologic study.

Demography↗

The research center for ultra-high voltage electron microscopy at Osaka University.

High-voltage electron microscopy has shown itself advantageous for the study of natural science, including biology, but especially for materials science. The most important advantage for materials science is for in situ experiments about the detailed processes of the phenomena that occur in bulk materials. The present paper is mainly concerned with several types of in situ experiments that have been carried out in the Research Center for Ultra-High Voltage Electron Microscopy, Osaka University. The following subjects have been studied: a) fundamental problems, such as the conditions necessary for in situ experiments, functional features of specimen treatment devices, and the effects of electron irradiation; b) the dislocation behavior of crystals under various conditions; c) high-temperature behavior of refractory materials, mainly ceramic composites; d) new applications of electron irradiation effects, such as amorphization of crystalline materials and electron-irradiation-induced foreign-atom implantation; e) environment-matter interaction, mainly chemical amorphization of alloys; and f) future trends of the in situ experiment, such as combinations with Auger valency electron spectroscopy and high-resolution electron microscopy.

Crystallization↗

Imaging regions of transport across human stratum corneum during high-voltage and low-voltage exposures.

Scanning confocal fluorescence microscopy was used to image localized regions of calcein transport across human stratum corneum during constant low-voltage (iontophoresis) and pulsed high-voltage exposures. Following an electrical protocol, imaging revealed regions of fluorescence which were interpreted as sites where transport of a fluorescent probe (calcein) into the stratum corneum had taken place. Electrically-assisted transport of calcein, whether enhanced by iontophoresis or high-voltage pulsing, appears to occur through intercellular and, to some extent, transcellular pathways into localized regions of stratum corneum that are not associated with appendages. Uniquely associated with the highest voltage pulses used (300 V across the skin) was the appearance of small, brightly fluorescent areas containing nonfluorescent interiors, i.e., fluorescent "rings". We present evidence which suggests that the dark interiors represent sites through which transport occurred during pulsing, but where calcein was no longer present at the time of imaging. Transport of charged microspheres into the stratum corneum was also observed.

Biological Transport↗

Control of glycoprotein synthesis. The purification by preparative high voltage paper electrophoresis in borate of glycopeptides containing high mannose and complex oligosaccharide chains linked to asparagine.

The heterogeneity of glycopeptides prepared from pronase digests of various glycoproteins has previously been demonstrated primarily by lengthy paper chromatography of oligosaccharides released from the glycopeptides by enzymatic or chemical means. We describe the use of high voltage paper electrophoresis in borate for the resolution of seven glycopeptides from ovalbumin and seven glycopeptides from human immunoglobulin G. This technique has been used in the preparation of glycopeptide substrates required for the study of certain glycosyltransferases and glycosidases.

Asparagine↗

Helicopter wire strike accident and high voltage electrocution: a case report.

Helicopter wire-strike accidents usually involve high-voltage lines or telephone wires where the resulting impact is low velocity with minimal loss of occupiable space. Death and injury in these mishaps is often due to blunt force trauma to the head. In a recent wire strike accident investigated by the Division of Aerospace Pathology at The Armed Forces Institute of Pathology, the circumstances suggest that death of both aviators was due to high-voltage electrocution. Evidence surrounding the case and high-voltage electrocution are discussed.

Accidents, Aviation↗

Management of high voltage electrical injury in children.

High voltage electrical injuries in children are rare. They produce severe internal damage to limbs resulting in a high incidence of amputation. Early, aggressive serial debridement ensures adequate removal of dead tissue. Flap coverage to defects is necessary. Secondary surgery is common, and delayed sequelae such as tendon rupture should be expected.

Abdomen↗

Proximal nerve conduction by high-voltage electrical stimulation in S1 radiculopathies and acquired demyelinating neuropathies.

OBJECTIVE: To evaluate the reliability and sensitivity of the high-voltage electrical stimulation for studying proximal conduction of peripheral motor axons in normal subjects, S(1) radiculopathies and acquired demyelinating neuropathies. METHODS: Twelve patients with compressive S(1) radiculopathy, 22 patients with acquired demyelinating neuropathy and 29 healthy volunteers were examined. The conduction of peripheral motor axons between lumbosacral roots and the sciatic nerve at the gluteal fold was investigated by high-voltage electrical stimulation delivered percutaneously. RESULTS: The main electrophysiological finding in S(1) radiculopathy was an abnormal side to side difference in the amplitude of the compound motor action potential by proximal stimulation. Overall, the frequency of abnormalities detected by using high-voltage electrical stimulation was similar to that found with conventional EMG studies, and the two methods showed electrophysiological alterations in the same patients. In all patients with acquired demyelinating neuropathy, the proximal motor nerve conduction velocity from lumbosacral roots to the sciatic nerve at the gluteal fold was reduced; proximal stimulation of the motor axons revealed electrophysiological abnormalities more often than when using other electrophysiological techniques (F wave and H reflex). CONCLUSIONS: High-voltage electrical stimulation of peripheral motor axons shows high sensitivity in detecting proximal neuropathies; it can also define the site and relevance of proximal lesions in the peripheral nervous system better than other conventional techniques.

Adult↗