As the technologic sophistication of generation and distribution of electrical energy has grown, so has the general concern about the effects of electric fields on human health. There can be no doubt that the significance of electrical trauma will continue to grow with our increasing use of power. It is apparent that our understanding of the various forms of electric trauma must increase, while we continue to promote safety near electrical hazards and develop effective medical therapies. Tissue damage as a result of electrical injury occurs by two mechanisms which are summative in action and have a variable degree of contribute to the ultimate damage produced. Thermal tissue damage occurs as a result of heat generated within the tissue (which offer an electrical resistance) secondary to the passage of the electrical current. High temperatures can also lead to cell membrane components, e.g., phospholipids, to dissolve. Electroportation damage is the tissue damage induced secondary to the strong electric field. Transmembrane potentials caused by electrical current result in the formation of pore in the phospholipid component of the cell membrane resulting in loss of function of the cell membrane with consequent cell death.
Animals ; Electric Injuries/physiopathology* ; Heart Injuries/physiopathology* ; Hemodynamics ; Humans ; Muscle, Skeletal/injuries*

OBJECTIVETo observe whether bladder controller can restore bladder function in paraplegic dogs.

METHODSFour dogs were studied after their T(10) spinal cord was transected. Electrodes implanted around S(2) bilaterally were connected to subcutaneous recievers. Microsurgical techniques were employed in dorsal rhizotomy at S(1 - 3) intradural segment. After daily stimulation, the results of bladder controller were evaluated by micturition and vesicography.

RESULTSMicturition was given under electrical stimulation with a urine volume of 80 - 140 ml per time. The mode of micturition was post-stimulus voiding. Vesicography showed that the bladder was filled and bladder neck was open in the micturition course of electric stimulation. Residual urine volume was 15 - 20 ml.

CONCLUSIONBladder controller together with a sacral deafferentation procedure can restore bladder function of paraplegic dogs.

Animals ; Disease Models, Animal ; Dogs ; Electric Stimulation ; Male ; Spinal Cord Injuries ; physiopathology ; surgery ; Urinary Bladder ; physiopathology ; surgery ; Urination

OBJECTIVES: To identify rat cavernous nerve and establish a rat model of erectile dysfunction caused by injury of cavernous nerve. METHODS: Ten rats were undergone dissections. 30 experimental rats were randomized into 2 groups, cavernous nerve were identified by electrical stimulation. One month after surgery, rat models were evaluated by electrical stimulation. RESULTS: The anatomic structure of cavernous nerve in rats are highly similar to human beings, the erection can be evoked by stimulating cavernous nerves, and after cavernous nerve injury it can not be evoked (P < 0.05). CONCLUSION Because of the highly similarity of cavernous nerve between rats and human beings, so as the suitable price, rat should be used as the ideal ED experimental animal. The model of ED caused by cavernous nerve injury is reliable.
Animals ; Disease Models, Animal ; Electric Stimulation ; Erectile Dysfunction/physiopathology* ; Ganglia, Autonomic/injuries* ; Male ; Penis/physiopathology* ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo study the changes in sciatic nerve blood flow and the expression of collagen type I after electric injury of rabbit nerve with different voltages.

METHODSThirty-six healty rabbits were randomized into 3 groups before receiving injury with electricity in voltages, i.e. 50 v, 75 v, and 100 v groups. The changes in blood flow of sciatic nerve were observed with Laser Doppler Flowmeter immediately after injury and 1, 4, 8 weeks after injury. The changes in the expression of collagen type I was observed by immunohistochemical method, and the positive expression rate was calculated.

RESULTSThe sciatic nerve blood flow increased in all groups immediately after electric injury. In the 75 v and 100v groups, the nerve blood flow [(53 +/- 3 ), (48 +/- 5) PU] was obviously lower than that of normal value [(62 +/- 4) PU, P < 0.05]. There was little collagen type I deposition in 50 v group, while brown collagenous fibers in epineurium and perineurium were observed in 75 v and 100v groups 4 and 8 weeks after injury. The expression of collagen type I in all groups were obviously higher than that of normal value, and that in 75v and 100 v groups were higher than that in 50 v group at bachl time-point (P < 0.01).

CONCLUSIONThe restoration of sciatic nerve blood flow is postponed following by the injury with increase of the electrical voltage. The collagen deposition after electrical injury may be one of the reasons for nerve blood flow decrease.

Animals ; Collagen Type I ; biosynthesis ; Electric Injuries ; blood ; physiopathology ; Nerve Regeneration ; Rabbits ; Random Allocation ; Sciatic Nerve ; blood supply ; injuries

Endogenous electric fields (EFs) have been detected at wounds and damaged tissues. The potential roles of EFs in tissue repair and regeneration have been an intriguing topic for centuries. Recent researches have provided significant insights into how naturally occurring EFs may participate in the control of tissue repair and regeneration. Applied EFs equivalent to the size of fields measured in vivo direct cell migration, cell proliferation and nerve sprouting at wounds. More remarkably, physiological EFs are a guidance cue that directs cell migration which overrides other well accepted directional signals including initial injury stimulation, wound void, contact inhibition release, population pressure and chemotaxis. EFs activate many intracellular signaling pathways in a directional manner. Modulation of endogenous wound EFs affects epithelial cell migration, cell proliferation, and nerve growth at cornea wounds in vivo. Electric stimulation is being tested clinically for the treatments of bone fracture, wound healing and spinal cord injury. EFs thus may represent a novel type of signaling paradigm in tissue repair and regeneration. Combination of the electric stimulation and other well understood biochemical regulatory mechanisms may offer powerful and effective therapies for tissue repair and regeneration. This review introduces experimental evidence for the existence of endogenous EFs and discusses their roles in tissue repair and regeneration.
Cell Division ; Cell Movement ; Cell Proliferation ; Electric Stimulation ; Electromagnetic Fields ; Humans ; Neurons ; physiology ; Regeneration ; Wound Healing ; Wounds and Injuries ; physiopathology

AIMStudy on the relationship between the degraded spinal cord injuries and the changes of the motor evoked potentials (MEP) to prove the diagnosis and prognosis value of MEP.

METHODSAfter injury at T8-T9 cord using modified Allen's weight-drop method, 27 male SD rats were divided randomly into control group (n = 5), group A (50 gcf, n = 8), group B (70 gcf, n = 8) and group C (100 gcf, n = 6). MEPs elicited by monopolar transcortical stimulation were recorded continuously before injury, just after injury, 15 minutes, 1 hour, 3 hours and 6 hours after injury. The rate of the size of the bleeding or necrosis area to the total cord was also calculated.

RESULTSMEP had no significant change in the control group. The amplitude of MEP's early components in group A or group B decreased or even obliterated after SCI, and then partially recovered, while the late components were lost without any recovery signals. All animals in group C showed no MEP waves excepting 2 rats had recovery signals. The size of the cord injuries area increased according to the dropping force and was correlated significantly with the amplitude of the largest peaks of scMEP 1 hour after SCI (r = -0.821).

CONCLUSIONThe scMEP changes after SCI are correlated with the injury forces and the pathological changes in the cord, which indicates that scMEP can be used as an objective index for the cord functional monitoring.

Animals ; Electric Stimulation ; Evoked Potentials, Motor ; physiology ; Male ; Rats ; Rats, Sprague-Dawley ; Spinal Cord Injuries ; pathology ; physiopathology

This paper reviews the current developing situation of neuroprostheses which are based on the functional electrical stimulation (FES) technique and are used to provide limb movements. It also discusses the major challenges of neuroprostheses, which will be faced in the future development and in the clinical applications for the rehabilitation of spinal cord injury and stroke.
Electric Stimulation Therapy ; methods ; trends ; Extremities ; physiology ; Humans ; Movement ; physiology ; Prostheses and Implants ; Prosthesis Design ; Spinal Cord Injuries ; physiopathology ; therapy ; Stroke ; physiopathology ; therapy

OBJECTIVETo investigate the effect of electrical stimulation to sacral spinal nerve 3 (S₃ stimulation) on gastrointestinal dysfunction after spinal cord injury (SCI).

METHODSSix rabbits were taken as normal controls to record their gastrointestinal multipoint biological discharge, colon pressure and rectoanal inhibitory reflex. Electrodes were implanted into S₃ in another 18 rabbits. Then the model of SCI was conducted following Fehling's method: the rabbit S₃ was clamped to induce transverse injury, which was claimed by both somatosensory evoked potential and motion evoked potential. Two hours after SCI, S₃ stimulation was conducted. The 18 rabbits were subdivided into 3 groups to respectively record their gastrointestinal electric activities (n=6), colon pressure (n=6), and rectum pressure (n=6). Firstly the wave frequency was fixed at 15 Hz and pulse width at 400 μs and three stimulus intensities (6 V, 8 V, 10 V) were tested. Then the voltage was fixed at 6 V and the pulse width changed from 200 μs, 400 μs to 600 μs. The response was recorded and analyzed. The condition of defecation was also investigated.

RESULTSAfter SCI, the mainly demonstrated change was dyskinesia of the single haustrum and distal colon. The rectoanal inhibitory reflex almost disappeared. S₃ stimulation partly recovered the intestinal movement after denervation, promoting defecation. The proper stimulus parameters were 15 Hz, 400 μs, 6 V, 10 s with 20 s intervals and 10 min with 10 min intervals, total 2 h.

CONCLUSIONS₃ stimulation is able to restore the intestinal movement after denervation (especially single haustrum and distal colon), which promotes defecation.

Animals ; Disease Models, Animal ; Electric Stimulation ; Electrodes, Implanted ; Evoked Potentials, Motor ; physiology ; Evoked Potentials, Somatosensory ; physiology ; Gastrointestinal Tract ; physiopathology ; Rabbits ; Sacrum ; innervation ; Spinal Cord Injuries ; physiopathology

Electrophysiologic examination of dorsal spinal cord injury (DSCI) is focused on transcranial magnetic stimulation induced motor evoked potentials. It were recorded at thenar muscles, exector spinae muscle, intercostals muscle, and internal oblique muscles. In complete spinal cord injury, the exector musle motor evoked potentials may occur although clinically that muscle shows no recovery. The ipsilateral exector and internal oblique muscles may be distributed by non-cross fibers in cerebrospinal tract. The progress in clinical sensory examination includes cutaneous electrical perceptional sensory threshold and quantitative sensory test. The former is more sensitive than two-points discrepentive test. Quantitative sensory test includes light touch threshold, vibration perceptual threshold, thermal threshold, pain, and cutaneous axon flare respone. It has been used in DSCI patients above and below the injury level. The thermal threshold elevates above the injury level in complete and incomplete DSCI patients.
Electric Stimulation ; Electromagnetic Fields ; Electromyography ; Evoked Potentials, Motor ; Evoked Potentials, Somatosensory ; Humans ; Neurologic Examination ; methods ; standards ; Sensory Thresholds ; physiology ; Spinal Cord Injuries ; physiopathology ; Thoracic Vertebrae

OBJECTIVETo explore the application of ultrasonography in the diagnosis of deep electric injury.

METHODSHP-IPHX high resolution color and pulse doppler ultrasonography was employed in the study. The hemodynamic indices were determined in the burn wound area and tissues 5 - 15 cm proximal to the wound in 12 patients with deep electric injury. At the same time, injuries to subcutaneous and muscular tissue and blood vessels (fifty-six blood vessels detected) were detected.

RESULTS1. It was found by two-dimentional ultrasonography that the injury degree in different tissue after deep electric injury was different, i.e. blood vessels were most liable to injury followed by muscles and subcutaneous tissue. In the burn wound area, endothelium was not visualized in 7 blood vessels and endothelial swelling was identified in 12 blood vessels. Furthermore, vascular occlusion was found in 4 blood vessels and thrombosis found in 5 vessels. 2. It was also demonstrated by color ultrasonography that change in course of blood vessel and tortuesity were observed in 12 blood vessels, stenosis of lumen in 21 vessels and widened intravascular space in 11 vessels, All these findings were confirmed in the subsequent operations. 3. It was revealed by pulse Doppler that the top blood flow speed increased during vascular contraction period in narrowed blood vessels with decreased blood flow per minute.

CONCLUSIONBeing an non-invasive examination, ultrasonography could directly demonstrate the morphological changes in subcutaneous tissue, muscle and blood vessels after a deep electric injury, which might help determine the injury degree and the hemodynamic changes in the injured site.

Adolescent ; Adult ; Blood Vessels ; diagnostic imaging ; injuries ; Burns, Electric ; diagnosis ; diagnostic imaging ; physiopathology ; Female ; Hemodynamics ; Humans ; Male ; Middle Aged ; Muscles ; diagnostic imaging ; injuries ; Skin ; diagnostic imaging ; injuries ; Ultrasonography, Doppler ; methods