Effects Of Electrical Stimuli Research Articles

Manipulation of Surface Electrical Charge on Nanocomposite Membranes Confers Wide Spectrum Bactericidal Effects and Promotes Tissue Regeneration

AbstractUtilization of electro‐responsive biomaterials with antibacterial properties is advantageous for facilitating septic wound healing and tissue regeneration. However, the dose‐response effects of electrical stimuli from these materials against bacteria are not rigorously characterized, and achieving synergy of bactericidal and pro‐regenerative effects of biomaterials remains a major challenge. Here, a graded series of flexible BaTiO3/P(VDF‐TrFE) electroactive nanocomposite membranes (EMs) are developed with varying surface charge intensities, to serve as antibacterial dressing for septic wound healing. EMs display broad‐spectrum antibacterial effects against both Gram‐positive and Gram‐negative bacteria in a dose‐dependent manner, depending on the magnitude of their surface electrical potential. Mechanistically, the surface charge of EMs increase intracellular levels of reactive oxygen species within bacteria cells, which in turn caused oxidative damage to the bacterial membrane, thereby suppressing bacterial activity and biofilm formation. Moreover, in vivo studies demonstrated that EMs effectively inhibited S. aureus infection and accelerated wound healing in a mouse skin defect model, as well as ameliorated P. gingivalis‐mediated periodontal inflammation in a mouse periodontitis model. Hence, this study optimizes the antibacterial properties of electroactive materials and characterizes the dose‐response effects of surface electrical charge against bacteria, thus validating the therapeutic applications of electroactive biomaterials in combating bacterial infection.

Electric stimulation promotes growth, mineral uptake, and antioxidant accumulation in kale (Brassica oleracea var. acephala)

Several studies have demonstrated that electric treatment has a positive effect, respectively, on germination, root growth and post-harvest quality. Nevertheless, there is still a lack of research on the effect of electric treatment on growth characteristics and quality of whole plants. Here, we explored the effect of electric fields on two cultivars of kale (Brassica oleracea var. acephala). Three levels of electric current (10, 50, and 100 mA) were applied to the nutrient solution of hydroponically grown plants for three weeks. Kale plants subjected to the electric fields, particularly 50 mA, had higher fresh and dry weights than the control. The absence of an electric field in a Faraday cage caused a significant decrease in shoot and root growth compared with the natural electric field (control). Electrostimulation enhanced nutrient uptake by activating root hair formation and active ion transport. Plants grown under 50 mA contained 72% more calcium, 57% more total phenolic compounds, and had a 70% greater antioxidant capacity than the control. This work provides foundational information regarding the effects of electrical stimulus on plants, which could enable the development of innovative culture technologies to improve crop yields and quality.

坐骨神経切除ラットにおける電気刺激が骨特性に与える影響

8 週齢雄性Wistar系ラット48 匹を用いて，電気刺激が骨特性に与える影響を調べた．対象を無作為に4 群に分け，1 群はSHAM術（SHAM群），残りの3 群は坐骨神経切除を行った．術後，坐骨神経切除（DN）群のうち2 群に対し，15または60 Hzの電気刺激（矩形波）を足関節底屈が起こるように両後肢後面に与えた．実験開始後，1，2，3，4 週間後に各群のラットを屠殺し，脛骨を取り出した．脛骨に対し3 点曲げ強度試験を行い，機械的骨強度を算出した．また，乾燥骨重量と灰量を測定した．DN群の骨特性は，術後1週間にはSHAM群に比して有意な低下を示した．また，15 Hz刺激群では，術後2 週間以降は全ての骨特性に対しSHAM群に比して有意な低下を示した．さらに，60 Hz刺激群では，術後2 週間より最大荷重値および灰量，術後3 週間で機械的骨強度，術後4 週間で乾燥骨重量の有意な低下を示したが，灰化重量密度は保たれた．本研究では，坐骨神経切除ラットにおける電気刺激による骨特性に対する影響は，骨萎縮の進行を遅らせる可能性が示された．また，電気刺激の骨特性への影響は，高周波刺激による方が効果は高いことが示された．

Effects of electrical stimuli on neuronal circuits of V1

Effects of electrical stimuli on neuronal circuits of V1

Cerebro-cerebellar interactions in man: neurophysiological studies in patients with focal cerebellar lesions

Recently Ugawa and co-workers reported that motor cortex excitability after magnetic stimulation in man can be reduced by coupling an electrical transcranial stimulus over the base of the skull. They hypothesised that the motor cortex inhibition observed was determined by activation of cerebellar structures. Nevertheless, the paradigm employed did not allow to exclude interference from extracerebellar structures due to spread of the electrical stimulus. In order to ascertain the role of the cerebellum in determining the modulation of the motor cortex excitability we examined, in 10 normal subjects and in 2 patients with unilateral cerebellar lesions, the effects of electrical stimuli over the base of the skull on the motor responses evoked by cortical magnetic stimulation. In both patients no inhibition of motor responses was present in the muscles ipsilateral to the lesion, whereas an inhibition, similar to that observed in controls, was evident on the opposite side. The present findings suggest the cerebellar origin of the motor effects seen after electrical stimulation of the base of the skull and further clarify the physiological cerebro-cerebellar interactions in man.

Effects of stimulating in raphe nuclei and in reticular formation on response of spinothalamic neurons to mechanical stimuli

1. The purpose of these experiments was to compare effects of electrical stimuli applied in two regions of the brain stem that are the sites of origin of descending bulbospinal systems; namely, the nucleus gigantocellularis of Brodal (7) and the nucleus raphe magnus, on the responses of lumbosacral spinothalamic neurons to mechanical stimuli. 2. In cats anesthetized with alpha-chloralose, stimulating in either of these structures with single pulses of current while the spinothalamic neuron was tonically activated by a sustained mechanical pressure resulted in an increase in the excitability of the cell followed by a prolonged suppression of its impulse activity. 3. For different neurons, the latency of the excitation ranged from 4 to 18 ms following the brain stem stimulus, while the latency of the suppression ranged from 16 to 34 ms. 4. In general, the effects of stimulating in the reticular formation and in the raphe nuclei were similar. although quantitative differences were found in the effects of each on different spinothalamic neurons. On the basis of these two studies, it is argued that the reticulospinal and raphe-spinal systems exert qualitatively similar effects on the responses of spinothalamic neurons evaluated in this experiment. 5. A comparison of the magnitudes of the suppression phase evoked from several different sites in the ipsilateral reticular formation and nucleus raphe magnus suggests that the descending systems arising from both these structures may be quite heterogeneous. 6. Stimulation of both regions of the brain stem produced a much greater suppression of the response of the spinothalamic neurons to slowly changing or sustained mechanical stimuli than to transient stimuli. It is suggested that the effects of descending systems arising both in the raphe nuclei and in the reticular formation on the responses of spinothalamic neurons to a mechanical stimulus are at least as dependent on the time course of the mechanical stimulus as they are on its intensity.

EXPERIMENTAL APPROACHES: Increased Excitability of the Heart Induced by Electrical Stimulation in the Absolute Refractory Period

A series of experiments were designed to study the possible effects of electrical stimuli, delivered during the absolute refractory period, on the threshold of excitability in the relative refractory period. They were carried out in dogs with complete A-V block or with intact conduction system. It was found that such stimuli, which previously were regarded as ineffective, may convert a subthreshold current to a depolarizing one. This effect was shown to be dependent on the time-relation between the “ineffective” and the test stimuli from the driving stimulus and also on the strength of the stimulations. The mechanism of the effectiveness of the ineffective stimulus was demonstrated to be a threshold-reducing, locally induced, anodal, all-or-none phenomenon. A series of experiments were designed to study the possible effects of electrical stimuli, delivered during the absolute refractory period, on the threshold of excitability in the relative refractory period. They were carried out in dogs with complete A-V block or with intact conduction system. It was found that such stimuli, which previously were regarded as ineffective, may convert a subthreshold current to a depolarizing one. This effect was shown to be dependent on the time-relation between the “ineffective” and the test stimuli from the driving stimulus and also on the strength of the stimulations. The mechanism of the effectiveness of the ineffective stimulus was demonstrated to be a threshold-reducing, locally induced, anodal, all-or-none phenomenon.

Oscillations and movements of mimosa leaves due to electric shock∗∗

Abstract A non‐destructive radio‐frequency Q‐Meter measurement system has been applied for measuring the effects of electrical stimuli from 50 to 150 Volts d.c. to leaves of Mimosa spp. These stimuli produced rapid petiolar angular velocities of an average of 0.3 rad/sec. and a linear velocity of signal conduction in the petiole of 20 mm/sec and from the primary pulvinus to the middle of a pinna of 41 mm/sec. The expanded rotational energy of a primary petiole corresponded to 2 × 10‐13 moles of ATP, which is much less than reported rates of dephosphorylation. However, the input of chemical equivalents of 1.1 × 10‐10 Faradays is in good agreement. Rapid oscillations of pinnules have been observed with remarkably constant periods of time in the range from 10 to 16 seconds. Evidence is given for considering them as minute leaf electroscopes, which are periodically charged and discharged by the dissipation of the charge from the electrical shock stimulus. This charge was shown to drain off from the primary pu...

Electronic Management of Fecal Incontinence

Electrical stimulation of the anal sphincter was used in six incontinent patients, resulting in control of fecal incontinence in five patients. One patient was unable to retain the electrode because of improper size and shape of the plug, which was cylindrical in contour. Only the external method was used, ie, variously shaped electrodes were inserted in the anal canal. Best results were obtained when hourglass-shaped plugs were used. It is postulated that control of fecal incontinence was achieved by contraction of the ana sphincter as well as by restoration of the tonus of the pelvic diaphragm. Since all patients had an indwelling urinary-tract catheter, no conclusions were drawn regarding the effect of electrical stimuli upon the urinary pathways. No adverse reactions were noted.

Semiautomatic speech intelligibility measurements

A recent study towards the improvement of intelligibility testing techniques has resulted in a very efficient testing procedure based on the use of the Fairbanks Rhyme Test and a computer. The Fairbanks Rhyme Test permits the actual tests to be taken quickly and simply, and the computer provides a rapid, thorough analysis of the test data. Subsequent evaluations of several vocoders, and of the effects of electrical stimuli upon test subjects, showed this testing procedure to be quite effective. Small differences in intelligibility between systems were detected by giving a large number of tests. A diagnostic evaluation of each system was performed by the computer, which pointed out specific shortcomings of each system under test.