Determination of metallization with energy-dispersive X-ray fluorescent spectrometry in experimental electric injury.

We investigated the application of energy-dispersive X-ray fluorescent spectrometry (EDX) analysis to the detection of aluminum (Al), tin (Sn) and zinc (Zn) as the electric conductor in experimental electrical injury. Experimental electrical injury was caused by exposure to alternating current at 100 V for 10 s. The peaks of Al, Sn, and Zn were detected by EDX in formalin-fixed skin samples of each current exposure group. Histological examination revealed blister formation in all samples of each current exposure group. EDX analysis technique can be applied to detect Al, Sn, and Zn as the electric conductor, and is useful in the diagnosis of electrocution.

The effect of elapsed time on cardiac troponin-T (cTnT) degradation and its relation to postmortem interval in cases of electrocution.

BACKGROUND: The estimation of postmortem interval (PMI) is of paramount importance for the police in their investigation when arriving at the scene of a questionable death. The aim of present study is to evaluate the effect of elapsed time on cardiac Troponin-T degradation and its association with PMI in cases of death due to electrocution. METHODS: Cardiac tissue samples were collected from medico-legal autopsies, after informed consent from the relatives. The cases included were the subjects of electrocution without any prior history of disease who died in the hospital and their exact time of death was known. The analysis involves extraction of the protein at room temperature for different time periods (∼5, 26, 50, 84, 132, 157, 180, 205 and 230 Hrs), separation by SDS-PAGE and visualization by Western blot using cTnT specific monoclonal antibodies. RESULTS: The results specify a characteristic banding pattern amongst human cadavers (n = 5), a pseudo-linear relationship between percent cTnT degraded and the time since death (R(2) = 0.87, p = 0.0001) was observed. The area of the bands within a lane was quantified by scanning and digitizing the image using Gel Doc (Universal Hood II). CONCLUSIONS: The post-mortem Troponin-T fragmentation observed in this study reveals a sequential, time-dependent process with the potential for use as a predictor of PMI in cases of electrocution.

Connexin 43, angiotensin II, endothelin 1, and type III collagen alterations in heart of rats having undergone fatal electrocution.

Death due to accidental electrocution occurs frequently. The aim of this study was to investigate alterations in cardiac connexin 43 (Cx43), angiotensin II (Ang II), endothelin 1 (ET-1), and type III collagen associated with fatal electrocution.Twenty-four Sprague-Dawley rats were divided into control, fatal electrocution (220 V, 50 Hz, 60 seconds), and electrical injury (220 V, 50 Hz, 60 seconds) groups. Animals were deeply anesthetized with sodium pentobarbital before each treatment, with the anode connected to the left foreleg and the cathode to the right hindleg, followed by cervical dislocation. Control animals received cervical dislocation alone. Immunohistochemical analysis was performed to evaluate the cardiac protein expression of Cx43, Ang II, ET-1, and type III collagen. Sections were analyzed by digital image analysis.The expression of Cx43 was significantly reduced after fatal electrocution, with the integrated optical density also lower when compared with control (P < 0.05). Expression of both Ang II and ET-1 was significantly increased after fatal electrocution, supported by integrated optical density when compared with control (P < 0.05). But no significant difference was found in type III collagen expression between the fatal electrocution group and the control group.In summary, cardiac protein expression of Cx43, Ang II, and ET-1 was found to be significantly altered with fatal electrocution, suggesting that these 3 proteins may be important underlying mechanisms of death during fatal electrocution. The current findings indicate that such alterations would be reflected in abnormal cardiac function and a possible cause of sudden death.

[The expressions of HSP 70 mRNA and c-fos mRNA in the skeletal muscle and cardiac muscle of rabbits by electrocuted].

OBJECTIVE: To study the changes of HSP 70 mRNA and c-fos mRNA expression and to find a method to differentiate antemortem from postmortem electrocution. METHODS: Fifteen New Zealand rabbits were randomly divided into three groups, the antemortem electrocution group, the postmortem electrocution group, and the control group. Each group consists of five rabbits. The levels of HSP 70 mRNA and c-fos mRNA in skeletal muscle and cardiac muscle were examined with quantitative fluorescent RT-PCR. RESULTS: The levels of HSP 70 mRNA and c-fos mRNA in the antemortem electrocution group increased significantly (P<0.05), compared with that of the postmortem electrocution group. CONCLUSION: The changes of HSP 70 mRNA and c-fos mRNA expression in skeletal muscle and cardiac muscle can be used as an indicator to distinguish antemortem from postmortem electrocution.

The expressions of HSP 70 mRNA and c-fos mRNA in the skeletal muscle and cardiac muscle of rabbits by electrocuted / 法医学杂志

OBJECTIVE@#To study the changes of HSP 70 mRNA and c-fos mRNA expression and to find a method to differentiate antemortem from postmortem electrocution.@*METHODS@#Fifteen New Zealand rabbits were randomly divided into three groups, the antemortem electrocution group, the postmortem electrocution group, and the control group. Each group consists of five rabbits. The levels of HSP 70 mRNA and c-fos mRNA in skeletal muscle and cardiac muscle were examined with quantitative fluorescent RT-PCR.@*RESULTS@#The levels of HSP 70 mRNA and c-fos mRNA in the antemortem electrocution group increased significantly (P<0.05), compared with that of the postmortem electrocution group.@*CONCLUSION@#The changes of HSP 70 mRNA and c-fos mRNA expression in skeletal muscle and cardiac muscle can be used as an indicator to distinguish antemortem from postmortem electrocution.

Cardiac monitoring of high-risk patients after an electrical injury: a prospective multicentre study.

OBJECTIVE: To report our experience monitoring patients with previously identified theoretical risk factors of significant electrical injury. METHODS: Patients who presented to one of 21 emergency departments between October 2000 and November 2004 were eligible to be enrolled in a prospective observational cohort study if after an electric shock they had one of several risk factors (transthoracic current, tetany, loss of consciousness or voltage source > or =1000 V) and therefore needed cardiac monitoring. RESULTS: Of the 134 patients enrolled, most were monitored because of transthoracic current (n = 60), transthoracic current and tetany (n = 39), tetany (n = 10), or voltage > or =1000 V (n = 10). There were 15/134 (11%) patients with abnormal initial ECGs. No patient developed potentially lethal late arrhythmia during the 24 hours of cardiac monitoring. CONCLUSION: Although only patients deemed at risk of late arrhythmias were monitored, none developed potentially lethal late arrhythmias. Asymptomatic patients with transthoracic current and/or tetany and a normal initial ECG do not require cardiac monitoring after an electrical injury with voltage <1000 V and no loss of consciousness.

[A study on expression of caspase-8 in organs of rats after electrical injury at antemortem or postmortem].

OBJECTIVE: This study was conducted to detect the expression of caspase-8 in organs of rats after The electrical injury so as to elucidate whether caspase-8 is useful in identifying electrical lesion. METHODS: experiment included two parts. In the first part (the antemortem electrical injury part), thirty-five healthy male SD rats were randomly divided into seven groups (n = 5 per group), i. e. the group of rats subjected to instantaneous electrothanasia; the groups of rats subjected to cervical dislocation at 1 h, 2 h, 4 h, 8 h after electrical injury; the sham group and the normal control group. In the second part (the postmortem electrical injury part), twenty-five healthy male SD rats wererandomly divided into five groups (n=5 per group), i. e. the groups of rats electrically injured just after death, and at 15 min, 30 min, 60 min after death; and the postmortem sham group. All experimental rats were given respectively an electric shock with two metal clamps that were connected with two poles of 220 V alternating current by clamping the rats' left hind limbs and right forelimbs. The rats of sham group after death were clamped but not electrified. The brain, lung, heart, liver, spleen, kidney, the muscle of electrified limb, the cutis of electrified limb of all experimental rats and those organs of control groups were dissected to detect the expression of caspase-8 by immunohistochemistry staining, and the staining intensities were assessed by image analysis system. RESULTS: In the antemortem electrical injury groups, the expression of caspase-8 was positive in brain, heart, liver and kidney; the strongest staining intensity appeard at 4 h after electrical injury and decreased at 8 h after electrical injury. In the group of rats electrically injuryed just after death, the expression of caspase-8 was faint, and the expression of caspase-8 in spleen, lung, muscle and cutis was negative in the other groups. The expression of caspase-8 in all detected organs was negative in the other rats that were electrified after death. CONCLUSION: Caspase-8 can be regarded as an index in identifying electrical injury and distinguishing between antemortem and postmortem electrical injuryies.

[Expression of c-Fos in rats organs after electrical injury].

OBJECTIVE: To study the expression of c-fos in organs after rats electrified. METHODS: The brain, lung, heart, liver, spleen, kidney, muscle of electrified limb, and cutis of electrified limb of all experimental rats and those organs of control groups were dissected to detect the expression of c-fos by using immunohistochemistry staining, and the staining intensity were assessed by image analysis system. RESULTS: The expression of c-fos was observed in brain, heart, liver, lung, kidney and muscle in electrified directly group, the amount of expression reached peak at 2 h after electrified and decreasing at 8 h after electrified, and the expression showed faintness in electrified at the immediate after death group. The expressions of c-fos in spleen and cutis is negative in all groups. The expression of c-fos in all detected organs was negative in other rats that were electrified after death. CONCLUSION: c-fos can be regard as a target in identifying electrical injury, whether it formed at antemortem or postmortem.

Changes in nitric oxide levels in striated muscles of rats following different types of death.

BACKGROUND: Nitric oxide is a signal molecule regulating the organism functions in living bodies. The aim of this study was to investigate the NO levels of striated muscles after different types of death in rats. METHODS: Nitric oxide levels in the muscles of masseter, triceps, and quadriceps obtained from right and left sides of 24 Spraque-Dawley rats following death were investigated. The rats were divided into three groups as cervical dislocation (control) group, electric shock group, and drowning group. After applying a light anesthesia, the rats were killed by cervical dislocation, electric shock and drowning. The samples were taken immediately and 120 minutes after death. RESULTS: In all muscle types of all groups, NO concentrations were lower in samples obtained 120 minutes after death than in those obtained immediately after death. NO concentrations were lower in the electric shock and drowning group than in the control group for both times. CONCLUSION: We can conclude that the type of death may affect the occurrence of rigor mortis and NO measurement may give an important clue in evaluation the mode of death.

Modulation of apolipoprotein D and apolipoprotein E expression in rat hippocampus after entorhinal cortex lesion.

Apolipoprotein (apo) D is a member of the lipocalin family of proteins. Although its physiological function is unknown, apoD is thought to transport one or more small hydrophobic ligands. A second apolipoprotein, apoE is known to play an important role in lipid transport, and apoE genetic polymorphism has been shown to be associated with susceptibility to Alzheimer's disease. Both apoD and apoE are expressed in the central nervous system (CNS) and both proteins accumulate at sites of peripheral nerve injury due to increased local synthesis. The two proteins may have overlapping or complementary functions within nervous tissue. In order to define the role of apoD within the CNS, we have studied the regional distribution of apoD and apoE mRNA and protein within the normal rat brain and the changes in apoD and apoE expression in the hippocampus of rats after entorhinal cortex lesion (EC lesion). Within the brains of normal rats, apoD expression in the hippocampus was as high as 180-fold that of the liver. ApoD mRNA levels in other areas of the rat brain ranged from 40 to 120 times the hepatic levels. The distribution of apoE gene expression within the brain was similar to that of apoD, but was much lower than hepatic apoE expression. When rats were subjected to EC lesion, the apoD message increased by 54% at 4 days post lesion (DPL) in the ipsilateral region of hippocampus while apoE mRNA levels (ipsilateral and contralateral) decreased by 43%. At 6 to 8 DPL apoD mRNA in the ipsilateral hippocampus remained elevated (42% above controls) whereas the apoE mRNA levels increased to about 15% above those of controls. At 14 and 31 DPL, both apoD and apoE expression was similar to controls. The increase in immunoreactive apoD in hippocampal extracts was more dramatic. At 1 DPL, immunoreactive apoD levels were already 16-fold higher than those in extracts of non-lesioned animals and, at 31 DPL, levels were still 8-fold higher than those of control animals. Finally, we have demonstrated that the levels of apoD in the brains of apoE-deficient mice are 50-fold those of wildtype control mice. ApoD clearly has an important function within the CNS in both normal and pathological situations.

Biological effects of electric shock and heat denaturation and oxidation of molecules, membranes, and cellular functions.

Direct exposure of cells in suspension to intense electric pulses is known to produce damages to cell membranes and supramolecular organizations of cells, and denaturation of macromolecules, much like injuries and tears seen in electric trauma patients. Thus, the system has been used as a laboratory model for investigating the biochemical basis of electric injury. An intense electric pulse can produce two major effects on cells--one caused by the field, or the electric potential, and the other by current, or the electric energy. The field-induced transmembrane potential can produce electro-conformational changes of ion channels and ion pumps and, when the potential exceeds the dielectric strength of the cell membrane (approximately 500 mV for a pulse width of a few ms), electro-conformational damages and electroporations of membrane proteins and lipid bilayers. These events lead to passage of electric current through the membrane-porated cells and to heating of cell membranes and cytoplasmic contents. The subsequent denaturation of cell membranes and cytoplasmic macromolecules brings about many complex biochemical reactions, including oxidation of proteins and lipids. The combined effects may cripple the cells beyond repair. This communication will focus on the thermal effects of electric shock. After a brief review of the current state of knowledge on thermal denaturation of soluble enzymes and muscle proteins, this paper will describe experiments on the thermal denaturation of cellular components and functions, such as nucleosomes, and the electron transport chain and ATP synthetic enzymes of the mitochondrial inner membranes. Data will show that lipid peroxidation and the subsequent loss of the energy-transducing ability of the cells may occur even at moderate temperatures between 40 degrees C and 45 degrees C. However, lipid peroxidation may be prevented with reducing reagents such as mercaptoethanol, dithiothreitol, and ascorbic acid. Reactivation of denatured cellular proteins and functions may also be possible and a strategy for doing so is discussed.

Transcript-specific effects of adrenalectomy on seizure-induced BDNF expression in rat hippocampus.

Activity-induced brain-derived neurotrophic factor (BDNF) expression is negatively modulated by circulating adrenal steroids. The rat BDNF gene gives rise to four major transcript forms that each contain a unique 5' exon (I-IV) and a common 3' exon (V) that codes for BDNF protein. Exon-specific in situ hybridization was used to determine if adrenalectomy has differential effects on basal and activity-induced BDNF transcript expression in hippocampus. Adrenalectomy alone had only modest effects on BDNF mRNA levels with slight increases in exon III-containing mRNA with 7-10-day survival and in exon II-containing mRNA with 30-days survival. In the dentate gyrus granule cells, adrenalectomy markedly potentiated increases in exon I and II cRNA labeling, but not increases in exon III and IV cRNA labeling, elicited by one hippocampal afterdischarge. Similarly, for the granule cells and CA1 pyramidal cells, hilus lesion (HL)-induced recurrent limbic seizures elicited greater increases in exon I and II cRNA hybridization in adrenalectomized (ADX) as compared to adrenal-intact rats. In this paradigm, adrenalectomy modestly potentiated the increase in exon III-containing mRNA in CA1 but had no effect on exon IV-containing mRNA content. These results demonstrate that the negative effects of adrenal hormones on activity-induced BDNF expression are by far the greatest for transcripts containing exons I and II. Together with evidence for region-specific transcript expression, these results suggest that the effects of stress on adaptive changes in BDNF signalling will be greatest for neurons that predominantly express transcripts I and II.

[Immunohistochemical study on ANP in the atria of electrocution].

By the immunohistochemical staining for ANP with LSAB method and the analysis of areas and grays of ANP with computer image analysis, it was found that the ANP granulus in right atria of electrocution were obviously depleted, compared with that in the control groups. The results showed that depletion of ANP granules in right atria could be used as a reference for the forensic diagnosis of electrocution and might benefit for the clinical therapy to the patients suffering from electric injuries.

[Immunohistochemical study on myoglobin in electrocution].

We have studied the changes of myoglobin (MB) IN heart muscle cells from eight corpses died of electrocution. The changes were compared with that of the heart muscle cells died of fall. The results indicated that the immunohistochemical changes of Mb were as follows: (1) blocky separate from heart muscle cell; (2) drift away into the interval of the heart muscle. The Mb changes were small parts of an area separate from heart muscle cells in control. The authors emphasized these changes were the characteristics of oxygen deficiency of the heart by electrocution.

[The dynamics of the early changes in the monoaminergic nervous apparatus of the spinal cord arteries in blunt trauma]. / Dinamika rannikh izmenenii monoaminergicheskogo nervnogo apparata arterii spinnogo mozga pri tupoi travme.

Changes in the adrenergic nervous system and population of tissue basophils of human spinal arteries in the course of 24 h after a blunt injury to the spine were studied. A staged pattern of development of compensatory adaptive reaction of the mechanisms regulating the spinal circulation has been revealed. The detected time course of posttraumatic changes may be interesting as it concerns the diagnosis of the time when a blunt injury to the spine was inflicted.

Transient and stable ionic permeabilization of isolated skeletal muscle cells after electrical shock.

Electroporation of skeletal muscle cell membranes has been postulated to cause myonecrosis in victims of major electrical trauma. To evaluate this concept we carried out a series of experiments to measure the transmembrane potential (delta Vm) threshold for skeletal muscle membrane electroporation using isolated mammalian skeletal muscle cells and compared this threshold with the expected range of delta Vm in victims of electrical trauma. Alterations in membrane Mg2+ or Ca2+ permeability in response to applied extracellular field pulses were quantified by measuring the kinetics of influx before and after field exposure. To avoid heating effects, 4-msec duration field pulses were used. The resting intracellular [Mg2+] was 0.86 +/- 0.01 mmol/l, and [Ca2+] was 0.1 +/- 0.01 microns. The delta Vm threshold for transient or stable electropore formation was determined by performing experiments over a wide range of applied fields. A delta Vm of 340 mV produced no significant change in intracellular [Mg2+]. Delta Vms ranging between 340 to 480 mV caused only a transient influx of Mg2+, indicating that spontaneous sealing of the membrane electropores occurred. A delta Vm of greater than 540 mV caused stable electropore formation. In addition, the efficacy of two surface active polymers as membrane sealing agents was tested. Either 1 mmol/L Poloxamer-188 (8.1 kDa) or 1 mmol/L neutral dextran (10.1 kDa) prevented Mg2+ influx after delta Vms greater than 540 mV (p < 0.001, n = 7). These results suggest that the fields produced in victims of electric shock are sufficient to damage cell membranes by a nonthermal mechanism and that nonionic surfactants may rapidly seal electropores.

Partial pressure of oxygen in brain and peripheral nerve during damaging electrical stimulation.

The studies were performed to elucidate the mechanism underlying the neural damage which may occur during prolonged electrical stimulation of either brain tissue or peripheral nerve. The partial pressure of oxygen (pO2) was measured in the sciatic nerve and the cerebral cortex of adult cats before and during direct, local electrical stimulation of these neural tissues, using stimulus parameters capable of inducing neural injury. pO2 was monitored by the polarographic method, employing a platinum microelectrode inserted into the tissue adjacent to or beneath the stimulating electrode. In the sciatic nerve there was no marked change in intrafascicular pO2 in three cats upon initiation of the electrical stimulation. In a fourth animal intraneural pO2 increased briefly upon initiation of the stimulation. In no case did the intrafascicular compartment of nerves become significantly hypoxic. In the cerebral cortex, the start of stimulation was accompanied by a significant increase (approximately 12-15 Torr) in intracortical pO2 beneath the stimulating electrode, and pO2 remained at or above the pre-stimulus value for the duration of the stimulation. These results show that extracellular hypoxia is unlikely to be a significant factor in the neural injury induced in brain or peripheral nerve by prolonged electrical stimulation.

[Ultrastructural changes in the skin in fatal electrical trauma]. / Ul'trastrukturnye izmeneniia kozhi pri smertel'noi élektrotravme.

The study was performed on 20 guinea-pigs. The animals were injured by alternating current at 380 and 220 V. The developing destructive alterations were characterized by histological, histochemical and electron-microscopic techniques, and a complex of electric markers was established. A dependence of morphological changes on the voltage values was demonstrated. The complex of alterations found may be employed for the differentiation of electric markers from mechanical or thermal injuries.