Evidence for an inhibition by endogenous galanin of neurogenic cutaneous vasodilatation in the pigeon

The effect of high affinity galanin antagonist M35 on neurogenic cutaneous vasodilatation has been studied in the pigeon using a Laser Doppler Imager. Cutaneous application of mustard oil or antidromic electrical stimulation of a cutaneous nerve produced a small increase in skin blood flow. Close arterial injection of M35 prior to chemical or electrical stimulation resulted in a marked augmentation of the vasodilatory response. This effect was abolished by chronic denervation. The results suggest a nerve-mediated inhibitory effect of endogenous galanin on neurogenic cutaneous vasodilatation in the pigeon skin and provide the first experimental evidence for an inhibitory local regulatory function of cutaneous sensory nerves at least in the avian skin.     

Characterization of electric-pulse-induced permeabilization of porcine skin using surface electrodes

We measured the transient and long-term changes of permeability of full-thickness porcine skin after the application of a single or a train of electric pulses, as the basis for optimization of the electrical parameters for enhancing transdermal drug or gene delivery by electroporation. Two electrodes were attached to the stratum corneum of excised skin for transdermal electric pulse delivery and impedance measurement. Both transient and long-term permeabilization were found to be dependent on the electrical exposure dose, i.e., the product of pulse voltage and cumulative pulsing (exposure) time. Skin resistance dropped to about 20% of its prepulsing value when pulsed beyond a critical dosage of 0.4 V-s (with 20-40 V across each skin path), but recovered rapidly within seconds after the pulse. Long-term permeabilization of the skin required repeated pulsing with a minimum potential of 160 V (80 V across each skin path). The maximum long-term resistance drop, to 35% of the initial value, required a dose greater than 200 V-s, recovering slowly and seldom completely in tens of minutes to hours. The decrease and recovery of the resistance were dependent on the frequency and pulse length only for low-dose electrical exposure.     

Rediscovering the science of the history of life

The effects induced by L-arginine (L-Arg) on the short-circuit current and potential difference of Pleurodema thaul skin were investigated. L-Arg, but not D-Arg significantly increased the short-circuit current and potential difference when applied to the serosal surface. The effects of L-Arg were antagonized by amiloride, NG-nitro-methyl-L-arginine (L-NAME) and by methylene blue. Carbachol and acetylcholine induced significant increases of both electrical parameters of the toad skin. These effects of the muscarinic cholinergic drugs were potentiated by a low concentration of L-Arg and antagonized by L-NAME or methylene blue. Carbachol and acetylcholine induced significant increases of both electrical parameters of the toad skin. These effects of the muscarinic cholinergic drugs were potentiated by a low concentration of L-Arg and antagonized by L-NAME or methylene blue. Addition of dibutyryl cyclic guanosyl monophosphate (db cGMP) or dibutyryl cyclic adenosine monophosphate (db cAMP) increased short-circuit current and potential difference. The effects of db cGMP, but not those of db cAMP were antagonized by L-NAME. The consecutive application of db cGMP and db cAMP induced additive effects. These results suggest that L-Arg increases transport in toad skin presumably acting through the formation of nitric oxide, which then stimulates cytoplasmic guanylate cyclase and leads to increased Na+ and K+ transport. The effects of L-Arg and carbachol were antagonized by acute application of morphine; however, a rebound response was observed when carbachol or noradrenaline were given after prolonged exposure of the skin to morphine, which suggests an adaptive response of the skin involving both cGMP and cAMP. Responses to both nucleotides were unchanged by morphine.     

Relation between light-induced intracellular and extracellular bioelectric reactions of plants]

The parallel registration of light-induced changes of electrical potential of the water plant Elodea has been made with the help of intracellular-microelectrode and extracellular-contact methods. It has been shown that the curve of the light-induced bioelectrical reaction (LBR) under the extracellular registration was similar to the curve of the first differential of light-induced changes of intracellular electrical potential (LIP), but with a negative sign. Thus, the kind of changing of LBR, as the first differential of LIP, may give information about intracellular potential of ground plants, for which the microelectrode way of registration was impossible. The likeness between LBR of Elodea and the ground plants studied suggests the general regularities in the light-induced changes of electrical potentials of different plants.     

Effect of oxytocin on transepithelial transport of water and Na+ in distinct ventral regions of frog skin (Rana catesbeiana)

Thoracic, abdominal, and pelvic fragments of ventral skin of Rana catesbeiana were analysed regarding the effect of oxytocin on: (1) transepithelial water transport; (2) short-circuit current; (3) skin conductance and electrical potential difference; (4) Na+ conductance, the electromotive force of the Na+ transport mechanism, and shunt conductance; (5) short-circuit current responses to fast Na+ by K+ replacement in the outer compartment, and (6) epithelial microstructure. Unstimulated water and Na+ permeabilities were low along the ventral skin. Hydrosmotic and natriferic responses to oxytocin increased from thorax to pelvis. Unstimulated Na+ conductance was greater in pelvis than in abdomen, the other electrical parameters being essentially similar in both skin fragments. Contribution of shunt conductance to total skin conductance was higher in abdominal than in pelvic skin. Oxytocininduced increases of total skin conductance, Na+ conductance, and shunt conductance in pelvis were significantly larger than in abdomen. An oscillatory behaviour of the short-circuit current was observed only in oxytocin-treated pelvic skins. Decrease of epithelial thickness and increase of mitochondria-rich cell number were observed from thorax to pelvis. Oxytocin-induced increases of interspaces were more conspicuous in pelvis and abdomen than in thorax.     

The electrical characteristics of human skin in vivo

PURPOSE: The objectives of this study were to investigate the impedance properties of human skin in vivo and to examine the effect of iontophoresis upon them. METHODS: Having established the intra- and inter-individual variation in basal values of skin impedance, the effect of varying iontophoretic current density, ionic strength and counter-ion on the rate of recovery of skin impedance after iontophoresis was investigated. RESULTS: Passage of an iontophoretic current caused a significant reduction in the magnitude of the skin impedance. Increasing the current density caused an even greater reduction in the value of the skin impedance and slowed the rate of recovery. Reduction of the ionic strength resulted in an increase in the rate of recovery following iontophoresis. A significant increase in the rate of recovery was observed when CaCl2 replaced NaCl as the electrolyte. Although visual inspection revealed the presence of greater erythema when CaCl2 was used, there was an absence of the mild sensation experienced by volunteers when using NaCl. The last part of the study established a correlation between transepidermal water loss and impedance analysis as complementary methods for probing skin barrier function in vivo. The data were fitted to an equivalent circuit consisting of a resistor in parallel with a constant-phase element and a mechanistic model proposed to explain the electrical properties of the skin. CONCLUSIONS: The first comprehensive investigation of the effect of iontophoresis on the electrical properties of human skin in vivo has been described. It would appear from the results, and from their interpretation, that impedance spectroscopy may be an effective method to quantify the impact of iontophoresis on the skin, and to determine the extent to which proposed drug delivery regimens will perturb skin barrier function.     

The correlation between skin electrical conductance and the score of qi vacuity

In traditional Chinese medicine, the syndrome of qi vacuity means that the patient's body has a low level of energy to react to stress. Recently, we used a score, the QV score, by scaling the severity of symptoms and signs of qi vacuity in patients with tiredness. The aim of this study was to investigate the relationship between QV score and skin electrical conductance in patients with tiredness. One hundred and forty-three healthy controls and 103 patients with tiredness were involved. Each subject received a weak electrical stimulation with constant voltage (1.75 volt), and conductance was measured between two different limbs. The mean value of skin conductance among four limbs was calculated and expressed by a special unit, namely Chin. The correlation between the skin conductance and QV score was analyzed by a linear regression analysis. The results showed that skin electrical conductance of healthy controls was negatively correlated with age (r-coefficient = -0.51, P = 0.000). The skin conductance of patients with tiredness was significantly lower than that of healthy controls with matching age (P = 0.000 by Student's t-test). Moreover, there was a positive correlation between the decrease of skin conductance and the QV score in patients with tiredness (r-coefficient = +0.68, P = 0.000). These results suggest that a decrease in skin electrical conductance may be closely related to the severity of qi vacuity. The skin conductance test is a simple, reliable, and quantitative method for detection of syndrome of qi vacuity.     

Two-way transdermal communication with the brain.

Describes the advantages and limitations of the transdermal stimoceiver, a system with 4 channels for electrical stimulation and 3 channels for electrical recording, to and from selected brain structures through the intact skin; by means of wireless links, the whole system may be used in completely unrestrained Ss. The system has been tested in goats with suitable controls, demonstrating that transdermal performance is similar to direct wire. Possibilities of the system for long-term depth EEG recordings, long-term electrical stimulation of the brain, communication from the brain to computer and back again, and clinical use in humans are noted. (23 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Electrosurgery for routine pediatric penile procedures

PURPOSE: Traditional teaching in urology has been to avoid electrosurgical devices in penile surgical procedures. In the last several years cutting current has been routinely used on the penis for making skin incisions, degloving, creating Byars flaps and destroying skin bridges. The purpose of this study was to determine the complications and final outcomes of electro-surgery. MATERIALS AND METHODS: A 5-year retrospective chart review was done to determine the complications and final outcomes of exclusively using electrical current to perform pediatric penile procedures. RESULTS: Electrosurgery was used to perform the entire surgical dissection in 346 patients, including circumcision in 124, repeat circumcision in 68, penoscrotal fusion/chordee repair in 127 and skin bridge procedures in 27. All patients had a satisfactory cosmetic result. After correction of penoscrotal fusion, separation at the scrotal suture line in 2 patients healed secondarily without sequelae. There was no hematoma, tissue necrosis or skin sloughing and all surgery was performed on an outpatient basis. CONCLUSIONS: Electrosurgery can be used safely and effectively for routine penile procedures, providing a bloodless operative field and excellent cosmetic results.     

Acinic cell Carcinoma of the parotid gland: CT and MRI

Skin permeation of amino acids through excised rat skin was measured at various pH values. The permeabilities varied with the donor pH and amino acid, indicating that each ionic species of amino acid may have a different permeability. The permeability coefficient of each ion was estimated from the permeability-pH profiles using the dissociation constants. The estimated values for mono-cation and uncharged zwitterion were not dependent on the lipophilicity but on the size of the amino acid, suggesting a porous mechanism of transport. The permeability coefficient was highest for di-cation, followed by mono-cation, positively charged, uncharged and negatively charged zwitterions. The electrical potential difference across the skin was too small to affect the permeation of ions. The permselective property of skin thus seems to be determined by the difference of diffusivity in aqueous pores of skin due to the hydration of ions and other factors.     

Assessing the potential of skin electroporation for the delivery of protein- and gene-based drugs

Although transdermal drug delivery has many potential advantages, the permeability of skin to macromolecules is extremely low. However, the application of short, high-voltage pulses to electroporate skin has recently been shown to make it reversibly permeable. A number of studies have demonstrated that electroporation-mediated transdermal delivery of peptides, polysaccharides, oligonucleotides and genes may be possible at clinically relevant rates, leading to the current commercial development of electroporation techniques.     

Classification et nomenclature des phénomènes électriques cutanés (activité électrodermale).

Discusses a standardized nomenclature-classification system for terminology used in electrodermography intended for French researchers. The proposed system considers both electrodermal processes that yield different types of skin electrical activity (including conductance, resistance, admittance, impedance, and skin potential) and components of the response itself (including frequency, amplitude, latency, duration, recovery time, and response morphology). A list of abbreviations corresponding to types of electrodermal activity and response during accommodation, rest, and continuous or punctuated stimulation is presented. (English abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Safety considerations to avoid current-induced skin burns in MRI procedures

The safety aspects of radiological methods continue to evolve. In this paper we report on two cases of skin burns in MRI caused by induced electrical current. A second- and a third-degree skin burn occurred during imaging in a 1.5 T system. The electromagnetic radiofrequency field inadvertently led to electrical currents caused by a conducting loop through the extremities and trunk. Skin burns induced by electrical current may occur in extremely rare cases even with standard MR imaging protocols operating within all current safety guidelines by inadvertently forming a closed conducting loop. By avoiding focal skin to skin contact of the extremities, this extremely rare adverse event can be avoided.     

Neonatal androgen and estrogen treatments masculinize the size of motoneurons in the rat spinal nucleus of the bulbocavernosus

Electrically-assisted transdermal delivery (EATDD) is the facilitated transport of compounds across the skin using an electromotive force. It has been extensively explored as a potential means for delivering peptides and other hydrophilic, acid-labile or orally unstable products of biotechnology. The predominant mechanism for delivery is iontophoresis, although electroosmosis and electroporation have also been investigated. The focus of this review is to put these different mechanisms in perspective and relate them to the drug and skin model system being investigated.     

Electrically Enhanced Boron Removal from Silicon Using Slag

An approach to enhance silicon refining using slag has been developed. The enhancement of the process was carried out by applying electrical potential difference across the slag and the silicon phase. This resulted in a shift in the apparent equilibrium in favor of higher partition ratio for the impurities. The application of electrical potential difference also enhanced the mass transfer rate increasing the overall kinetics of the process. This has been demonstrated in laboratory experimentations for the removal of boron from silicon-boron melts using slag. A CaO-SiO₂-Al₂O₃ slag was reacted with Si-B melt at 1823 K (1550 °C). Electrical potential differences were applied through graphite rods immersed in each of the liquid phase. The results showed that the apparent B-partition ratio and the apparent slag mass transfer coefficient were increased by a factor of 1.2 and 1.4, respectively, when a potential difference of 3 V was applied to the phases. The technique has the potential to be used for improving the existing slag refining process by increasing the overall kinetics and the slag capacity to absorb the impurities.     

Familiar jaws with new twists

Transcutaneous electrical nerve stimulation (TENS) is an effective modality for the treatment of pain. TENS use is well tolerated and has relatively few complications. Potentially serious complications of TENS use include disruption of cardiac pacemaker function and electrical artifact during electrocardiographic monitoring. Electrical interference with cardiac monitoring using parasternal electrodes and electrocardiographic (EKG) artifact with an epidural stimulator has been reported. We report the case of EKG artifact produced by surface TENS electrodes applied to the thoracic and lumbar regions. The electrical signal produced by the TENS unit created an electrocardiographic artifact resembling a pacemaker spike on routine EKG. This was interpreted as a malfunctioning cardiac pacemaker. The easily misinterpreted electrical spikes that can result from TENS use as seen in this case highlights the need for physician awareness of this potential complication.     

Central and peripheral actions of the NSAID ketoprofen on spinal cord nociceptive reflexes

Ketoprofen is a non-steroidal antiinflammatory drug (NSAID) which provides effective analgesia in situations of pain provoked by tissue inflammation. However, the location of its analgesic effects, (peripheral tissues versus central nervous system), have not been clearly identified and separated. In the present study the effectiveness of ketoprofen was examined in two different types of experiments: (i) Open field behavioural tests in conscious rats, and (ii) spinal cord nociceptive reflexes (single motor units) activated by electrical and thermal stimulation in chloralose anaesthetised rats. The experiments were performed in rats with carrageenan-induced inflammation of one hindpaw, or of one knee joint. The administration of ketoprofen significantly inhibited the reduction of exploratory movements caused by inflammation in open field experiments. Ketoprofen was also effective in depressing reflex activity evoked by electrical and noxious thermal stimulation of the skin, either in inflamed tissue or in normal tissue of monoarthritic animals. It was also effective in the reduction of reflex wind-up; a phenomenon in which the activity of spinal cord neurones increases progressively with high frequency electrical stimulation. We therefore conclude that ketoprofen has central as well as peripheral analgesic activity.     

Vibrational spectra of glycine, alanine and proline oligomers in relation to their polymeric forms

The cutaneous recording of the gastric electrical activity according to the modified method of Sobakin was utilized. In fasting individuals changes in potential occured between 2 and 5 per min., in most of the cases after standard breakfast the frequency increased while lower amplitudes appeared. The frequency of electrical waves from the duodenum increased remarkably. It could be demonstrated that the peristalsis recorded by gastroscopy was synchronous with the electrogastrographic potentials. The applicability of the method for clinical diagnostic purposes is limited at the present time, because a "normal" electrogastrogram has not yet been established. Specific changes of the electrogastrogram have not been observed in various gastric diseases, which may be verified by routine diagnostic procedures.     

The human stapedius reflex by ipsilateral electrical stimulation of the auditory meatal skin (author's transl)

A modified method for eliciting a stapedius reflex by electrical stimulation of the meatal skin is presented. In contrast to the acoustically elicited stapedius reflex, the electrically-induced response is only ipsilateral, and can be ablated by anesthesia of the meatal skin. Contralateral acoustical and ipsilateral electrical stimulations lead to a summation effect of the amplitude off the stapedius reflex. When presented simultaneously, subthreshold electrical and acoustical stimulations may produce a reflectory contraction of the stapedius muscle. Similar responses can be found in diseases of the middle ear and the facial nerve. The method described is not difficult to perform, is painless to the patient, and can be used objectively in neurotologic testing.