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PubMed1992

The influence of anterior root stimulation (S2) in deafferented spinal cord injury men on cavernous electrical activity.

Registration of cavernous electrical activity (single potential analysis of cavernous electrical activity) was recently suggested for the diagnosis of autonomic cavernous dysfunction. For validation of this method the effect of sacral neurostimulation on cavernous electrical activity was examined. In 3 male patients with a complete spinal cord lesion (T3, T4 and T12, respectively), deafferentation was done at the S2 to S5 levels. Around the anterior roots of S2 to S5 electrodes for neurostimulation were placed. Cavernous electrical activity was recorded with an intracavernous needle electrode and with surface electrodes in the flaccid as well as in the erect states induced by neurostimulation (at 7, 8, 12, 18, 20, 30 and 45 Hz., 30 v. and 0.4 msec). In all patients similar potentials compared to the normal values, as well as additional pathological potentials were recorded during flaccidity. During neurostimulation all patients achieved full erection with no or markedly decreased cavernous electrical activity to frequencies of 12, 18, 20 and 30 Hz., while to 7, 8 and, more pronounced, 45 Hz. only partial erection with ongoing cavernous electrical activity was found. Our study strongly suggests that cavernous electrical activity and, subsequently, the cavernous smooth muscle tone are dependent on autonomic input. This finding supports the hypothesis that single potential analysis of cavernous electrical activity may be valid in the diagnosis of cavernous autonomic dysfunction. Furthermore, our results suggest a possible role for single potential analysis of cavernous electrical activity in the fine tuning of erection inducing neurostimulators.

Adult↗
PubMed1999

Fos-like immunoreactivity in the auditory brainstem evoked by bipolar intracochlear electrical stimulation: effects of current level and pulse duration.

Fos-like immunoreactivity was used to compare the auditory brain stem excitation elicited by bipolar electrical stimulation of the cochlea at various current levels relative to the electrically evoked auditory brain stem response threshold for a 50-micros/phase monophasic pulse. Fos-like immunoreactive cells were labeled in primary auditory brain stem regions. The distribution of labeled cells was restricted to regions known to be cochleotopically related to the stimulated region of the scala tympani. Some labeled cells were observed at 2x electrically evoked auditory brain stem response threshold. The number, density and spatial distribution of labeled cells were quantified in the dorsal cochlear nucleus and inferior colliculus, and found to increase with increasing level of stimulation. For 50-micros pulses, the location of labeled neurons remained reasonably restricted to narrow bands within each region until the 1Ox level of stimulation (20 dB above electrically evoked auditory brain stem response threshold) was reached. While a monotonic increase in Fos-like immunoreactivity with increasing stimulus level was observed in most nuclei, for cells of the superficial layer of the dorsal cochlear nucleus, a non-monotonic change with increasing stimulus level was seen. This dorsal cochlear nucleus non-monotonicity may indicate that, at higher levels of stimulation, a secondary indirect inhibitory input, probably associated with activation of deep layer dorsal cochlear nucleus cells, reduces excitatory responses at the superficial layer of the dorsal cochlear nucleus. Electrically evoked auditory brain stem response and Fos expression showed parallel changes as a function of stimulus level and pulse duration. The data indicate that discrete activation of cell populations within the central auditory pathways can occur with bipolar electrical stimulation to the highest levels of stimulation typically useful in humans. The data also indicate a close, but not identical, quantitative relationship between Fos-like immunoreactivity and electrophysiological response amplitude. These findings support the view that a study of Fos-like immunoreactivity can provide a powerful and quantitative tool for study of the dynamic response characteristics of cells of the central auditory system to electrical stimulation at suprathreshold levels. The data suggest that there is a monotonic increase in the number of neurons responsive to intracochlear electrical stimulation as a function of stimulus level, at least through the upper half of the dynamic range, but that this increase does not result in a complete loss of spatial selectivity. Coupled with previous psychophysical studies, these results suggest that the increase in the number of activated neurons is functionally beneficial, resulting in improved discrimination of changes in the electrical signals.

Animals↗
PubMed2006

Electrical signals control wound healing through phosphatidylinositol-3-OH kinase-gamma and PTEN.

Wound healing is essential for maintaining the integrity of multicellular organisms. In every species studied, disruption of an epithelial layer instantaneously generates endogenous electric fields, which have been proposed to be important in wound healing. The identity of signalling pathways that guide both cell migration to electric cues and electric-field-induced wound healing have not been elucidated at a genetic level. Here we show that electric fields, of a strength equal to those detected endogenously, direct cell migration during wound healing as a prime directional cue. Manipulation of endogenous wound electric fields affects wound healing in vivo. Electric stimulation triggers activation of Src and inositol-phospholipid signalling, which polarizes in the direction of cell migration. Notably, genetic disruption of phosphatidylinositol-3-OH kinase-gamma (PI(3)Kgamma) decreases electric-field-induced signalling and abolishes directed movements of healing epithelium in response to electric signals. Deletion of the tumour suppressor phosphatase and tensin homolog (PTEN) enhances signalling and electrotactic responses. These data identify genes essential for electrical-signal-induced wound healing and show that PI(3)Kgamma and PTEN control electrotaxis.

Animals↗
PubMed2000

Three-dimensional analysis of object properties during active electrolocation in mormyrid weakly electric fishes (Gnathonemus petersii).

Weakly electric fishes are nocturnal and orientate in the absence of vision by using their electrical sense. This enables them not only to navigate but also to perceive and recognize objects in complete darkness. They create an electric field around their bodies by producing electric signals with specialized electric organs. Objects within this field alter the electric current at electroreceptor organs, which are distributed over almost the entire body surface. During active electrolocation, fishes detect, localize and analyse objects by monitoring their self-produced electric signals. We investigated the ability of the mormyrid Gnathonemus petersii to perceive objects three-dimensionally in space. Within a range of about 12 cm, G. petersii can perceive the distance of objects. Depth perception is independent of object size, shape and material. The mechanism for distance determination through electrolocation involves calculating the ratio between two parameters (maximal slope and maximal amplitude) of the electrical image which each object projects onto the fish's skin. During active electrolocation, electric fishes cannot only locate objects in space but in addition can determine the three-dimensional shape of an object. Up to certain limits, objects are spontaneously categorized according to their shapes, but not according to their sizes or the materials of which they are made.

Animals↗
PubMed2006

Caregivers' perceptions of electric versus manual toothbrushes for the institutionalised elderly.

OBJECTIVE: To evaluate how caregivers feel about the use of electric vs. manual toothbrushes for the elderly in long-term care. MATERIALS AND METHODS: After electric toothbrushes had been accessible in an institution for 15 months, a self-administered questionnaire was distributed to the nursing staff. The questions posed were whether the electric toothbrushes were being used, how much time was spent on brushing and if electric toothbrushes simplified the provision of oral care for the residents. RESULTS: The response rate was 79%. Of the 119 respondents, 78% replied that they always or frequently used an electric toothbrush. With regard to brushing times, 44% of the respondents reported that they spent less time on oral care procedures with an electric toothbrush than with a manual one. Equal amount of time for both types of toothbrushes was reported by 53%. Only 3% reported spending more time with an electric toothbrush than with a manual one. Oral care procedures were considered simpler with this device by 63% of the respondents, 22% registered no change and 15% found it more difficult. If patients suffering from dementia were considered separately, 45% found the procedures simpler when using electric toothbrushes, 24% registered no difference and 31% found it more difficult. CONCLUSION: The findings indicate that when given the choice, the caregivers prefer to use electric toothbrushes rather than manual ones as they feel this is simpler and often less time-consuming.

Aged↗
PubMed1991

Evidence for a link between mechanical and electrical alternans in acutely ischaemic myocardium of anaesthetized dogs.

In order to examine the relation between mechanical alternans and associated electrical alternans during acute myocardial ischaemia, we determined the effect of a ventricular premature beat and calcium antagonists on mechanical and electrical alternans during acute coronary occlusion in anaesthetized dogs. Isometric contractions and unipolar electrocardiograms were recorded from ischaemic myocardium. During coronary occlusion, mechanical alternans was accompanied by electrical alternans, which was an alternate change in the ST segment elevation, i.e. the higher ST and the lower ST. Electrical alternans was frequently discordant and in some cases accompanied by discordant mechanical alternans. Both discordant electrical and mechanical alternans became concordant and were potentiated after the ventricular premature beat. In all cases, concordant mechanical alternans was accompanied by concordant electrical alternans and vice versa. In this situation, the higher and the lower ST corresponded to the larger and the smaller contractions respectively. Thus, a fixed correspondence was observed between mechanical and electrical alternans. A fixed correspondence was also observed between mechanical alternans and the variation in the time taken for repolarization of the monophasic action potential. Verapamil and diltiazem inhibited both electrical and mechanical alternans. The present results support the idea that a common mechanism, such as a beat-to-beat cycle of the transmembrane and intracellular movement of calcium ions, may play a role in the mechanisms of electrical and mechanical alternans.

Animals↗
PubMed1972

A comparison of chemical and electrical synaptic transmission between single sensory cells and a motoneurone in the central nervous system of the leech.

In leech ganglia, three sensory cells of different modality converge on a motoneurone, where they form chemical and electrical synapses. Each of these synapses behaves in a characteristic manner and the nature of the transmission mechanism has significant functional consequences for the operation of the reflexes. An analysis has been made of the effects of trains of impulses on synaptic transmission through these pathways, using frequencies that correspond to natural firing.1. At the chemical synapse between the nociceptive sensory cell and the motoneurone, two opposing events occur: facilitation and depression. Thus, with trains of impulses, the synaptic potentials first increase in amplitude and then decrease. The two processes could be separated by altering the Mg and Ca content of the bathing fluid. In concentrations of Mg that reduced the amplitude of a single control chemical synaptic potential, pure facilitation occurred during a train. Depression predominated during brief trains in raised concentrations of Ca, although synaptic potentials were initially larger. These results suggest that changes in the amount of transmitter released by each presynaptic action potential can account for the changes observed in chemical synaptic transmission.2. In contrast, electrical transmission between the sensory cell responding to touch and the same motoneurone did not show facilitation or depression. The electrical coupling potential in the motoneurone was relatively constant when the touch cell fired at high or low frequencies in normal Ringer fluid, high Mg, or high Ca fluid.3. Further differences between chemical and electrical synapses were apparent when the preparation was cooled to 4 degrees C. In the cold the latency of chemically evoked synaptic potentials in the motoneurone increased and their amplitude declined drastically with repetitive stimulation, while electrical coupling potentials were unaffected.4. A brief hyperpolarization of the presynaptic cell by injected current produced a marked and prolonged increase in chemically evoked synaptic potentials, but did not influence electrical synaptic transmission.5. The synapses of the sensory cell responding to pressure, which are both chemical and electrical, behaved as expected: the chemical synaptic potentials showed facilitation and depression while electrical transmission remained relatively constant.6. These experiments emphasize the different functional consequences of electrical or chemical synapses in reflex pathways for the transmission of signals that arise as a result of natural sensory stimuli.

Action Potentials↗
PubMed1981

The mature electrical properties of identified neurones in grasshopper embryos.

1. We have examined the mature electrical properties of five identified neurones in embryos of the grasshopper Schistocerca nitens. The five cells arise from two different precursor cells: the median neuroblast, whose first three progency are called DUM 3,4,5; DUM 4,5; and DUM 5; and mid-line precursor 3, which divides once to produce the H cell and the H cell sibling.2. Electrical coupling was investigated by dual intracellular penetrations. Action potentials were elicited by intracellular stimulation of cell bodies and by extracellular stimulation of axons. The ionic basis of action potentials was investigated by changing the ionic environment and by applying various blocking agents.3. Most of the mature electrical properties of all five cells appear by day 13 of embryonic development. They change little through hatching on day 20.4. The recorded resting potential for all five cells varies from -55 to -60 mV and the recorded input resistance varies from 200 to 450 MOmega. All five cells show delayed rectification, much of which is blocked by tetraethylammonium (TEA). Their resistance increases as they are hyperpolarized.5. The five cells do not appear to be electrically coupled between days 13 and 20.6. All five neurones generate mature action potentials and in several cases show cell-specific electrical properties by day 13. The ionic dependence and depolarizing phase of the action potential change little between days 13 and 20; some changes occur in the after-hyperpolarization.7. One cell-specific difference is observed in normal saline. Four of the cells have axons, median neurites, and somata which generate action potentials in normal saline; but one of the cells (the H cell sibling) has an inexcitable soma and generates action potentials only in its axon.8. Another cell-specific difference in the soma action potentials of DUM 3,4,5,; DUM 4,5; DUM 5; and the H cell is observed when outward current is blocked by TEA. In three of the cells, TEA causes the short-duration action potential (2-4 msec) to be converted into a long-duration action potential (100-1000 msec) in which there is an initial spike (Na(+)-dependent) followed by a long plateau (Ca(2+)-dependent). In the other cell, DUM 5, at resting potential the addition of TEA only causes a shoulder (Ca(2+)-dependent) on the falling phase of the action potential. DUM 5 and DUM 4,5 thus have different electrical properties, even though they differ only by a single cell division from the precursor cell.9. In all four neurones which normally generate soma action potentials (DUM 3,4,5; DUM 4,5; DUM 5; and the H cell), the inward current is carried by both Na(+) and Ca(2+). On day 13, either inward current alone can generate the overshooting action potential; in contrast, by day 18, neither inward current alone can generate an overshooting response. The inward current of the axon action potential in all five cells is carried predominantly by Na(+).10. Thus, the progeny of two different embryonic precursor cells (median neuroblast and mid-line precursor 3) show a broad spectrum of electrical properties. The mature phenotype of electrical excitability is not a property shared in common by all the progeny of a single embryonic precursor cell in the grasshopper. Conversely, progeny from different precursor cells can share the same mature phenotype of electrical excitability.

Action Potentials↗
PubMed1995

Growth effects of electrically stimulated contraction on adult feline cardiocytes in primary culture.

The purpose of this study was to determine effects of long-term electrical stimulation of cardiocyte contraction on protein synthesis rates and total protein content. Adult feline cardiocytes were plated on laminin-coated culture trays and maintained in a serum-free medium consisting of M199 supplemented with ascorbate, bovine serum albumin, creatine, carnitine, taurine, and 10(-7) M recombinant insulin. Cardiocytes were electrically stimulated to contract with use of continuous electrical pulses of alternating polarity at a frequency of 1 Hz and pulse duration of 5 ms. Nonstimulated cardiocytes are normally quiescent and were used as the control group. In control quiescent cardiocytes, protein synthesis rate decreased by 14% between days 1 and 4 in culture and then remained stable through day 7. In electrically stimulated cardiocytes, protein synthesis rates increased by 19% between days 1 and 7. Protein synthesis rates were 18% higher on day 4 and 43% higher on day 7 in electrically stimulated than in quiescent cardiocytes. Protein content per cell was determined by measuring total fluorescence per cell by use of confocal microscopy of fluorescein isothiocyanate-stained cells. Electrical stimulation significantly increased cellular protein content by 52% after 7 days compared with controls. Quiescent and electrically stimulated cardiocytes remained rod shaped, retained their myofibrillar architecture, and were responsive to electrical stimulation over the 7-day period. These data demonstrated that electrically stimulated contraction of adult cardiocytes resulted in cell growth, as assessed by an increase in protein content per cell over 7 days in culture. This increase was due, at least in part, to an acceleration of steady-state protein synthesis rates.

Animals↗
PubMed2004

Functional properties of electrical synapses between inhibitory interneurons of neocortical layer 4.

The existence of electrical synapses between GABAergic inhibitory interneurons in neocortex is well established, but their functional properties have not been described in detail. We made whole cell recordings from pairs of electrically coupled fast-spiking (FS) or low threshold-spiking (LTS) neurons, and filled some cells with biocytin for morphological reconstruction. Data were used to create compartmental cable models and to guide mathematical analysis. We analyzed the time course and amplitude of electrical postsynaptic potentials (ePSPs), the subthreshold events generated by presynaptic action potentials, in both FS and LTS neurons. The results imply that the generation of ePSPs is predominantly a linear process in both cell types for presynaptic firing of both single and repetitive spikes. Nonlinearities shape ePSPs near spike threshold, but our data suggest that the underlying synaptic current is still a linear process. Cell-to-cell electrical signaling on longer timescales also appears to be linear. Cable models of electrically coupled FS and LTS neurons imply that the analyzed electrical synapses are, on average, within 50 mum of the soma. Finally, we show that electrical coupling between 2 inhibitory cells promotes synchrony at all spiking frequencies. This contrasts with the effect of reciprocal inhibitory postsynaptic potentials (IPSPs) evoked by the same cells, which promote antisynchronous firing at frequencies less than about 100 Hz. Electrical coupling counteracts the antisynchronous behavior induced by IPSPs and facilitates spiking synchrony. Our results suggest that electrical synapses among inhibitory interneurons are most readily described as low-pass linear filters that promote firing synchrony.

Analysis of Variance↗
PubMed2002

Cutaneous electrical stimulation of acupuncture points may enhance gastric myoelectrical regularity.

BACKGROUND/AIM: Cutaneous electrical stimulation has been reported to be as effective as electroacupuncture. The aim of this study was to test whether cutaneous electrical stimulation had the same effect as electroacupuncture to enhance the regularity of myoelectrical activity. METHODS: Fifteen healthy male volunteers were enrolled for this study. Electrogastrography (EGG) was performed for 30 min at the baseline, 30 min during electroacupuncture or cutaneous electrical stimulation, and for an additional 30 min thereafter. RESULTS: During 3 Hz of electroacupuncture on the Zusanli point, there was a significant increase in the percentage of normal frequency. The percentage of normal frequency in the post-acupuncture period was also increased, but it was not statistically significant when compared to the baseline. There was a significant decrease in the tachygastric and bradygastric rhythm during electroacupuncture on the Zusanli points. There were similar changes of EGG parameters with cutaneous electrical stimulation on the Zusanli points. The percentage of normal frequency during cutaneous electrical stimulation increased significantly. However, the percentage of normal frequency in the post-cutaneous electrical stimulation period was similar to the baseline. There was a significant decrease in the percentage of tachygastric rhythm during cutaneous electrical stimulation on the Zusanli points. However, there was no significant change in the percentage of bradygastric rhythm during and after the cutaneous electrical stimulation periods. CONCLUSIONS: The effect of cutaneous electrical stimulation on the percentage of normal frequency and tachygastria is similar to electroacupuncture. Nonetheless, the changes of the percentage in bradygastria are not significant.

Acupuncture Points↗
PubMed2004

Platinum complex cytotoxicity tested by the electrical resistance breakdown assay.

The electrical resistance breakdown assay provides a novel approach for the quantification of cytotoxic activity of platinum based anticancer drugs. It is a functional assay system for cancer cell invasion that detects nanoscale alterations of an epithelial test barrier prior to microscopic morphometric changes. We measured changes in transepithelial electrical resistance (TEER) of a tight epithelial MDCK-C7 monolayer in response to highly invasive amelanotic melanoma cells (A7-clone) in combination with different platinum complexes (cis-, oxali- and carboplatin). The efficiency of the electrical resistance breakdown assay was compared a standard method for measurement of cytostatic activity, the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. The MTT-assay utilizes mitochondrial enzymatic activity to draw conclusions from a functional cell metabolism to the number of living cells in a sample. When human melanoma cells were seeded on top of an electrically tight MDCK-C7 monolayer, electrical leakage occurred within 48 h of co-culture. Electrical resistance breakdown was effectively prevented by cisplatin and its analogs (no significant difference between 100 microM cisplatin and corresponding controls with non-invasive cells). The results of the electrical resistance breakdown and MTT-assay were linearly dependent. Significance of both tests was equivalent, but the electrical resistance breakdown assay gave additional functional information. Compared to oxali- and carboplatin, cisplatin was more effective in preventing TEER-breakdown than reducing the number of tumor cells, giving rise to the assumption that cisplatin can reduce tumor cell number as well as invasiveness. In conclusion the electrical resistance breakdown assay provides a sensitive, continuous and cell-based assay system for the quantification of cancer cell invasiveness and evaluation of chemotherapeutics under physiological conditions.

Animals↗
PubMed1993

Assessing human exposure to power-frequency electric and magnetic fields.

This paper reviews published literature and current problems relating to the assessment of occupational and residential human exposures to power-frequency electric and magnetic fields. Available occupational exposure data suggest that the class of job titles known as electrical workers may be an effective surrogate for time-weighted-average (TWA) magnetic-field (but not electric-field) exposure. Current research in occupational-exposure assessment is directed to the construction of job-exposure matrices based on electric- and magnetic-field measurements and estimates of worker exposures to chemicals and other factors of interest. Recent work has identified five principal sources of residential magnetic fields: electric power transmission lines, electric power distribution lines, ground currents, home wiring, and home appliances. Existing residential-exposure assessments have used one or more of the following techniques: questionnaires, wiring configuration coding, theoretical field calculations, spot electric- and magnetic-field measurements, fixed-site magnetic-field recordings, personal- exposure measurements, and geomagnetic-field measurements. Available normal-power magnetic-field data for residences differ substantially between studies. It is not known if these differences are due to geographical differences, differences in measurement protocols, or instrumentation differences. Wiring codes and measured magnetic fields (but not electric fields) are associated weakly. Available data suggest, but are far from proving, that spot measurements may be more effective than wire codes as predictors of long-term historical magnetic-field exposure. Two studies find that away-from-home TWA magnetic-field exposures are less variable than at-home exposures. The importance of home appliances as contributors to total residential magnetic-field exposure is not known at this time. It also is not known what characteristics (if any) of residential electric and magnetic fields are determinants of human health effects.

Electric Wiring↗
PubMedDate not supplied

The effect of electric field on callus induction with rape hypocotyls.

The influence of electric field treatment on dedifferentiation and calli formation on rape hypocotyls was investigated. Segments, 10 mm long, of the upper part of rape (Brassica napus L., cv. Góczański) hypocotyls were stimulated by different combinations of voltage/time (1.5 V/120 h, 3 V/3 h, 10 V/15 min and 30 V/30 s) under in vitro conditions. With all electric field treatments, segments oriented with their apical part towards the cathode produced more calli as compared to control (non-treated with electric field). Under opposite orientation slight inhibition of callus growth was observed. As the strongest effect on callus growth was observed after treatment with 30 V/30 s, this electric field treatment was selected for following analyses: the incorporation of [14C]-2,4-D (2,4-dichlorophenoxyacetic acid) and [14C]-BAP (benzylaminopurine) from the culture medium, changes in ACC (1-aminocyclopropane-1-carboxylic acid) level and the redox activity in apical and bottom parts of hypocotyls during 18 d of culture. In contrast to changes in fresh weight, electric field treatment (30 V/30 s) stimulated a higher accumulation of 2,4-D and BAP in basal parts of hypocotyls than in apical ones. Moreover, orienting the apical part towards the cathode resulted in lower uptake of hormones as compared with the opposite orientation. The ACC concentration increased, especially in the basal parts of hypocotyls, independently on electric field application. However, the highest level was observed after electric field treatment with orientation of the apical part towards the anode. The distribution of oxidative substances (measured as the amount of ferric ions) between the apical and bottom part of hypocotyls was not changed when the apical parts were oriented towards the cathode. Under these conditions a decrease in apical and an increase in basal parts was observed during culture. Opposite orientation influenced the redistribution of oxidative substances from the first day of electric field treatment. Based on these results we suggest that electric field action can be connected with its influence on specific concentration of oxidative substances and hormone distribution in cells.

Brassica napus↗
PubMed2004

Transient electrical coupling delays the onset of chemical neurotransmission at developing synapses.

The formation and subsequent elimination of electrical coupling between neurons has been demonstrated in many developing vertebrate and invertebrate nervous systems. The relationship between the disappearance of electrical synaptic connectivity and the appearance of chemical neurotransmission is not well understood. We report here that identified motoneurons from the snail Helisoma formed transient electrical and chemical connections during regeneration both in vivo and in vitro. Electrical connections that formed in vivo were strongest by day 2 and no longer detectable by day 7. During elimination of this electrical connection, an inhibitory chemical connection from 110 onto 19 formed. This sequence of synaptic development was recapitulated in cell culture with a similar time course. The relationship between the appearance of transient electrical coupling and its possible effects on the subsequent chemical synaptogenesis were examined by reducing transient intercellular coupling. Trophic factor-deprived medium resulted in a 66% reduction in coupling coefficient. In these conditions, the unidirectional chemical connection formed readily; in contrast, chemical synaptogenesis was delayed in cell pairs exposed to trophic factors where transient electrical coupling was strong. Dye coupling and synaptic vesicle cycling studies supported electrophysiological results. Exposure to cholinergic antagonists, curare and hexamethonium bromide, which block chemical neurotransmission in these synapses, resulted in prolonged maintenance of the electrical connection. These studies demonstrated an inverse relationship between chemical and electrical connectivity at early stages of synaptic development and suggest a dynamic interaction between these forms of neuronal communication as adult neural networks are constructed or regenerated.

Animals↗
PubMed1979

Induced ischemia: means of prediction of demarcation line of necrosis after electrical injury. An experimental study on rabbit ear.

Necrosis due to an electrical injury extends by progressive obstruction of blood vessels. Means of inhibiting expansion of necrosis and predicting early the demarcation line after an electric injury were studied in the local electric injury of a rabbit ear produced by application of an electric current of 50 Hz, 1800 V for 1 sec between the right ear and the right posterior leg. Although no effective method of inhibiting expansion of necrosis was obtained, a method of predicting a demarcation line of necrosis was obtained by inducing ischemia of the ear early after the application of an electric current. From three hours to three days after the application of the electric current, ischemia of the ear was induced by compressing it between a pair of blood pressure cuffs at a pressure of 300 mmHg. As a result, the area proximal to the expected demarcation line of necrosis became white by ischemia, while the peripheral part remained dark red because of thrombi, and the expected demarcation line was clearly observed. Two to three weeks after the application of the electric current, the ear almost invariably fell off at this expected line. Therefore, in the electric injury of the hand, it can be distinguished clinically whether or not the area will become necrotic by inducing ischemia from the tips of the fingers to the upper arm early after the electric injury.

Animals↗
PubMed1999

An in vitro assessment and a pilot clinical study of electrical resistance of demineralized enamel.

Electrical resistance measurement was evaluated in vitro and in vivo as a method for comparing the remineralizing performance of toothpastes. In the in vitro study, areas of sound enamel on 12 unrestored, mature, extracted human molars and bicuspids, with electrical resistance readings greater than 99.99 M omega, were demineralized to an electrical resistance of 1 to 4 M omega. The teeth were divided into three groups. The change in electrical resistance was measured following a 15 cycle regimen of treatment, demineralization and salivary soaking. Treatments were five-minute exposures to either a 1:2 slurry in saliva of Enamelon (E), a remineralizing fluoride-toothpaste also containing soluble calcium and phosphate ions, a 1:2 slurry in saliva of Crest (C), a conventional fluoride toothpaste (P), or to saliva alone. Demineralization was performed with a 30-minute exposure to 0.1 M lactic acid 50% saturated with calcium hydroxyapatite. The salivary soaking was 1 hour in duration. The mean electrical resistance of the E, C and the saliva treated sites was 63.9 +/- 4.3, 37.6 +/- 9.5 and 2.1 +/- 0.7 M omega, respectively. The final resistance was statistically different for each group (p < 0.05). A pilot clinical study was then conducted to assess the electrical resistance technology in vivo. Eighteen adult subjects with at least one site of early enamel caries with an electrical resistance between 1.0 M omega and 20.00 M omega were randomly assigned to either Enamelon, Crest, or a non-fluoride placebo toothpaste and asked to brush twice daily. After three months, the mean resistance of the test sites was 23.57 M omega for E, 9.61 M omega for C and 13.24 M omega for P. However, the mean resistance changes did not proceed consistently over time. At the end of the study, the electrical resistance measurements on four sites out of twelve in Group E were suggestive of remineralization, whereas measurements on one site out of ten were suggestive of remineralization in Group C and two or three sites out of twelve were suggestive of remineralization in Group P. Progression of demineralization was possibly indicated in only one site, which was in Group C. There were insufficient subjects for statistical significance in the pilot clinical study. There were apparent problems with the variability of some measurements between visits in the in vivo study. Overall, however, the results of both studies indicate that with modifications to the equipment, electrical resistance measurements may be a means of comparing the remineralization performance of toothpastes.

Adult↗
PubMed2001

The effect of supplementary antioxidant therapy in patients who report hypersensitivity to electricity: a randomized controlled trial.

CONTEXT: Hypersensitivity to electricity is a proposed environmental illness of unknown etiology. Patients report a variety of symptoms that they relate to electric equipment. The afflicted individuals suffer from ill health. Many interventions have been tried but, to date, there is no one specific treatment that has been proven superior to other remedial actions. In general, there is a lack of controlled prospective studies. OBJECTIVE: To test the hypothesis that antioxidant therapy reduces symptoms and improves health in patients reporting hypersensitivity to electricity. DESIGN: Randomized, double-blind, crossover, placebo-controlled study. SETTING: Patients referred to the Environmental Illness Research Centre, Stockholm County Council. PATIENTS: Sixteen patients reporting hypersensitivity to electricity. INTERVENTION: Antioxidant supplementation (vitamins C and E, selenium). MAIN OUTCOME MEASURES: Self-reported symptoms and reported degree of hypersensitivity to electricity, serum levels of uric acid and diphenylpycrylhydrazyl (DPPH). RESULTS: The results indicated no significant differences in reported symptoms, reported hypersensitivity to electricity, or oxidative status in serum between periods of antioxidant and placebo treatments. Serum levels of DPPH and uric acid showed no correlation with the reported degree of symptoms or hypersensitivity to electricity. CONCLUSIONS: The study did not show any beneficial effect of antioxidant supplementation for patients reporting hypersensitivity to electricity. The results do not support the hypothesis that oxidative stress is a major contributor to ill health in patients who report hypersensitivity to electricity.

Adult↗