Skin Resistance Research Articles

Cavitation mechanisms in ultrasound-enhanced permeability of ex vivo porcine skin

Ultrasound-induced cavitation is known to enhance transdermal transport of drugs for local and systemic delivery. However, the specific cavitation mechanisms responsible are not well understood, and the physical location of permeability-enhancing cavitation is also unknown. The experiments reported here investigated the role of stable and inertial cavitation, both within the skin and at the dorsal skin surface, in ultrasound enhancement of skin permeability. Full-thickness porcine skin was hydrated with either air-saturated phosphate buffered saline (PBS) or vacuum-degassed PBS to localize cavitation activity within or outside the skin, respectively. Skin samples were sonicated for 30 minutes over a range of frequencies (0.41 and 2.0 MHz) and peak rarefactional pressure amplitudes (0-750 kPa) with a 20% duty cycle (1 s on, 4 s off). Cavitation activity was monitored using a 1.0 MHz unfocused, wideband passive cavitation detector (PCD). Changes in skin permeability were quantified by measuring the electrical resistance of skin every 10 seconds during insonation. Subharmonic acoustic emissions revealed a strong correlation with decreasing electrical resistance of skin when cavitation was isolated within the tissue, suggesting that stable cavitation within the skin plays a primary role in ultrasound-enhanced permeability over the frequencies investigated.

Expert System of the Fiber-Optical Detection for Colon Hydropathy

Colon hydropathy implies that the filtrated water pumped into the rectum keeps regular colon squirm, and sweeps away poisonous excrements. The PC-based ryodoraku technique has played increasingly important role in the field of traditional Chinese medicine because of its advantages of better preventive diagnosis, less side effects and inexpensive medicare. Since the 1950’s, Dr. Nakatani Yoshio has developed the ryodoraku methodology to measure skin resistance for the purpose of preventive diagnosis based on Chinese acupuncture and the qi-field theory. From the viewpoint of the preventive medicine, rehabilitated smooth muscles and well-balanced probiotics would improve self-repair functions and reduce the carcinogen of the colon. However, long-lasting hydropathical process for existed products on the market may result in unpredictable side effects from the viewpoint of drug dynamics. On the other hand, repeated use of colonoscopes could not only be expensive but contaminative in considering of colon viruses. This paper is focused on the clinical research of the drug dynamics and the development of a PC-based technique in the colon hydropathy. A clinical platform with disposable optical fibers is schemed to assure the biomorphic balance of colon. Finally, clinical experiments are carefully schemed to justify the advantages of the proposed algorithm in Tse-En Clinic of Traditional Chinese Medicine.

Evaluation of Textile Electrodes for Electrotherapy

This study evaluates the suitability of new textile electrodes manufactured by Textilforschungsinstitut Thuringen-Vogtland e. V. (TITV). This open, controlled trial included 25 healthy young volunteers. New textile electrodes and conventional adhesive electrodes were compared. Therefore, transcutaneous electrical nerve stimulation (TENS), medium-frequency neuromuscular electrical stimulation (NMES), and EMG-triggered stimulation was conducted on the participant’s thighs. The discomfort experienced was rated on the visual analogue scale (VAS). Change in skin resistance level (SRL), skin temperature and pain pressure threshold (PPT) was measured. The current intensity used for effective stimulation was noted, and the participants were asked for their preferred type of electrodes. Initially, textile electrodes are less comfortable and SRL and skin temperature are lower. The changes in surrogates, if present, do not differ between textile or adhesive electrodes. The textile electrodes evaluated in this study can generally be used for TENS, NMES, and EMG biofeedback therapy. To allow proper stimulation, the electrodes have to be wetted and applied with pressure. Wetting and applying with pressure are disadvantages that should be improved in further prototypes.

Is Commercially Available Point Finder Accurate and Reliable in Detecting Active Auricular Acupuncture Points?

This study was done to determine the specificity and sensitivity of a commercial Pointer Plus (Point finder) in detecting a region of low skin resistance on the ear. This was a prospective blinded study. The study was done at the Yale New Haven Hospital, New Haven, CT. The subjects were men and women who work at Yale New Haven Hospital. There were no interventions. Correlations were made between self-reported musculoskeletal pain and the detection of low skin resistance on the ear. The positive predictive value for Pointer Plus detecting low skin resistance correlating to the neck region of French auricular map is 0.76 (76%). The positive predictive value for Pointer Plus to detect low skin resistance area correlating to the low back region of French auricular map is 0.25. The positive predictive value for Pointer Plus in detecting any low in skin resistance on the external auricles in patients who complained of more than two musculoskeletal pains is 0.29. The specificity and sensitivity of a commercial Pointer Plus (point finder) in detecting a region of low skin resistance on the ear being unreliable, depending on the correlating area based on a published auricular map. Additional assessments are needed to support the clinical practice.

Aging is associated with a diminished axon reflex response to local heating on the gaiter skin area

ObjectivesElderly patients are susceptible to skin ulcerations on the supramedial malleolar area of the leg. Our aim was, using local thermal hyperemia, to study microvascular function on the gaiter skin area of elderly, but otherwise healthy volunteers, because abnormal microvascular reactivity could contribute to ulcerations in this region. MethodsTwo groups of healthy volunteers were enrolled according to age, including 20 subjects aged from 18 to 30years (young group) and 42 subjects aged from 60 to 86years (older group). Local thermal hyperemia to 43°C was performed for 1h using heating circular probes and skin blood flow was recorded using Laser Doppler Imaging, with or without 2h lidocaine/prilocaine cream application. Sodium nitroprusside iontophoresis was also performed. ResultsThe initial local thermal hyperemia peak was lower in the older group (14.7mV/mmHg±6.9) compared to the young group (19.9±7.2, P=0.009). Lidocaine/prilocaine cream decreased the initial local thermal hyperemia peak and the late plateau for all groups. The local thermal hyperemia plateau and sodium nitroprusside iontophoresis corrected for skin resistance did not differ between older and younger subjects. ConclusionsPhysiological aging is associated with an altered initial axon reflex response to local heating in the supramedial malleolar skin. Further work is required to determine whether these changes are more pronounced in frail and dependent groups and whether they could explain the higher incidence of skin ulcerations in the supramedial malleolar skin associated with venous insufficiency and neuropathy.

Galvanic skin resistance (GSR) biofeedback in tension-type headache – Auditory, visual or combined feedback: Which is beneficial? A randomized controlled trial

AbstractBackground: The efficacy of electromyograph (EMG) biofeedback (BF) in the treatment of tension-type headaches (TTH) has been extensively studied, but very few studies have been done comparatively to study efficacy of galvanic skin resistance (GSR) BF. Moreover, no studies have reported the efficacy of isolated audio, visual and combined GSR BF in TTH. Objectives: The present study aimed at studying the efficacy of GSR BF using auditory, visual and combined feedback in patients with TTH. Design: Randomized, controlled study. Participants, settings: 143 subjects were recruited. Of these, 121 subjects (76 females and 45 males) were randomly assigned using the lottery method to four groups receiving auditory (n = 30), visual (n = 30), combined GSR BF (n = 30) and control group (n = 31), respectively. Intervention: Each subject (except control group) received 15 sessions of BF for 30 min each in an isolated room in the physiotherapy outpatient department. The control group received only medication pres...

Rubber dam use less stressful for children and dentists

Randomised controlled trial, single centre and operator. 72 patients (6-16 years) assessed as compliant, with no allergies, not on significant medication were divided into two groups by 'drawing sealed lots'. 234 fully erupted teeth were sealed. Molars and/or premolars were sealed dependant on age. Teeth were pre-cleaned with prophy paste. In the controls, teeth were isolated with buccal and lingual cotton rolls and salivary ejector in the intervention group a rubber dam was used. The same etching, rinsing and placement protocol was used in both arms. Outcomes were: patients' subjective measures of pain using a visual analogue scale; blood pressure (before and after treatment), breath rate, pulse rate and skin resistance at five time points. The operator's pulse rate was measured and they completed a questionnaire on subjective mental and physical stress following treatment. Treatment times were recorded. The breath rate was significantly (P < 0.05) lower and the skin resistance level was significantly higher during treatment with rubber dam compared to the control group. Subjective pain perception was significantly lower for the test group. The treatment time needed for the fissure sealing procedure was 12.4% less in the test group. The authors state; '... in the hands of an experienced dentist, isolation with rubber dam is less stressful for children and adolescents than isolation with cotton rolls, and can save valuable treatment time.' The operator's stress measures were lower with rubber dam and treatment time was reduced.

Impact of Surgical Intervention and Postoperative Pain on Electrical Skin Resistance at Acupuncture Points: An Exploratory Study

One theory about acupuncture suggests that pathological processes can cause measurable changes in electrical skin resistance (ESR) at acupuncture points (APs). Although the theory has yet to be proven, ESR measurements (ESRMs) form a frequently used part of contemporary acupuncture. The aim of this study was to test the so-called 'electrical responsiveness' of APs in the setting of a defined operative trauma. ESRMs (n=424) were performed at the APs and surrounding skin of GB34 and ST38 in 163 participants using an impedance meter array developed for the purpose of ESRMs. For each group the percentage of measurements with a significantly different ESR between the APs and the surrounding skin was calculated and compared with each other. Measurements of four groups were compared: healthy control subjects (n=30) and patients after ophthalmic (n=29), hip (n=42) and shoulder (n=30) surgery. The influence of postoperative pain intensity was also assessed. Group comparison showed no significant differences for ST38. The ESRMs at GB34 had a significantly higher percentage of measurements with an increased ESR after ophthalmic (23.2%) and hip (22.2%) surgery, but not after shoulder surgery (7.5%). Subgroup analysis showed that an increase in pain intensity tended to lead to a decrease in the number of APs with ESR changes. These results suggest that reactive changes in ESR at APs might exist. Pain and alertness seem to have an impact on ESR at APs. However, the current data do not allow for conclusions to be drawn concerning the clinical use of ESRMs.

Balanço hídrico e a distribuição geográfica dos anfíbios.

Given the high cutaneous permeability of amphibians, their inter-specific variation in aspects of water balance could be associated to patterns of distribution in environments that differ in water availability. Comparative studies including species from different biomes evidence adaptations of several variables associated to water balance, such as dehydration tolerance, skin resistance to water loss, and rates of water uptake. However, to understand the underlying mechanisms of amphibian geographical distribution and sensitivity to environmental change, ecological and behavioral aspects must be integrated to physiology under a historical approach of clade diversification and environmental occupancy.

Expert System of Chinese Medicine on the Moving Robotic Platform

The PC-based ryodoraku technique has played increasingly important role in the field of traditional Chinese medicine because of its advantages of better preventive diagnosis, less side effects and inexpensive medicare. Since the 1950’s, Dr. Nakatani Yoshio has developed the ryodoraku methodology to measure skin resistance for the purpose of preventive diagnosis based on Chinese acupuncture and the qi-field theory. However, the physician can hardly measure and adjust the qi-field biological energy of the limb meridians because of the clinical complexities for the moving robotic platform handicappers. In this paper, the ryodoraku theory of the limb meridians is modified by the bladder meridian detection on the spinal cord of handicappers so that they can acquire better clinical therapy. A PC-based expert system is developed on the crystal panel to detect bladder energy and make real-time acupuncture therapy according to the qi-field reactions on the spinal meridian of the examinee. Finally, clinical experiments are carefully schemed to justify the advantages of the proposed algorithm in Tse-En Clinic of Traditional Chinese Medicine.

Single-Frequency LCR Databridge Impedance Measurements as Surrogate Measures for the Integrity of Human Skin

While LCR databridge instruments are used to probe the integrity of skin, there is confusion in this literature about what these instruments report in series (SER) or parallel (PAR) modes at user-specified measurement frequencies, typically 100 or 1,000 Hz. Here, the theoretical meanings of resistance and capacitance measurements in PAR and SER mode are presented. A large body of data from human cadaver skin are used to show that LCR databridge resistance measured at 100 Hz in PAR mode and capacitance measured at 100 Hz in SER mode are most sensitive to skin resistivity, which is the electrical measurement most closely related to skin integrity. The single-frequency databridge resistance values are shown to correlate to skin permeability measurements using tritiated water.

50 Years Ago in The Journal of Pediatrics: Observations on Skin Resistance to Electricity and Sweat Chloride Content: A Preliminary Report

50 Years Ago in The Journal of Pediatrics: Observations on Skin Resistance to Electricity and Sweat Chloride Content: A Preliminary Report

Electrotactile Display with Real-Time Impedance Feedback Using Pulse Width Modulation.

An electrotactile display is a tactile interface composed of skin surface electrodes. The use of such a device is limited by the variability of the elicited sensation. One possible solution to this problem is to monitor skin electrical impedance. Previous studies revealed a correlation between impedance and threshold, but did not construct real-time feedback loops. In this study, an electrotactile display was constructed using a 1.45 μs feedback loop. Real-time pulse width modulation was proposed, and the relationship between skin resistance and absolute threshold was measured to find a function for determining a suitable pulse width from skin resistance. An evaluation experiment revealed that the proposed algorithm suppressed spatial variation and reduced temporal change.

Influence of local or systemic corticosteroids on skin wound healing resistance

PURPOSE: To compare the resistance of skin wound healing of mice submitted to local or systemic hydrocortisone administration, in different postoperative periods. METHODS: An incision and suture was performed on the thoracic skin of 130 male mice: Group 1 (n = 10) resistance of the integer skin; Group 2 (n = 30) submitted only to skin incision and suture; Group 3 (n = 30) skin incision and suture followed by administration of saline fluid; Group 4 (n = 30) skin incision and suture followed by administration of local hydrocortisone; Group 5 (n = 30) skin incision and suture followed by administration of systemic hydrocortisone. The resistance of the wound healing and the weight of the animals were studied on the seventh, 14th and 21st postoperative days. Histological examination was also performed. RESULTS: The mice that received corticoid (groups 4 and 5) presented significant decreasing on their weight (p = 0.02). The Groups 3, 4 and 5 showed lower scar resistance than Group 2 on the seventh postoperative day (p &lt; 0.05). On the 14th and 21st days, there was no difference on the skin would healing resistance (p &gt; 0.05). CONCLUSION: Administration of hydrocortisone in mice is responsible for weight decreasing and reduction of the skin wound healing resistance during the first postoperative week.

Influence of rubber dam on objective and subjective parameters of stress during dental treatment of children and adolescents – a randomized controlled clinical pilot study

Rubber dam is recommended for isolating the working field during adhesive dentistry procedures; however, dentists often omit rubber dam, particularly in paediatric dentistry, supposing that it would stress the patient. The aim of this study was to evaluate stress parameters during a standardized dental treatment procedure performed with or without rubber dam. The treatment time was measured as a secondary outcome variable. This study was designed as a randomized, controlled, clinical study with 72 patients (6-16 years; mean age, 11.1). During standardized fissure sealing procedures, objective parameters of stress (e.g., skin resistance, breath rate) were recorded. The operator's stress level was measured by pulse rate. Subjective pain (patients) and stress perception (operator) were evaluated by an interview. The breath rate was significantly (P<0.05) lower and the skin resistance level was significantly higher during treatment with rubber dam compared to the control group. Subjective pain perception was significantly lower for the test group. The treatment time needed for the fissure sealing procedure was 12.4% less in the test group. Isolation with rubber dam caused less stress in children and adolescents compared to relative isolation with cotton rolls if applied by an experienced dentist.

Using electrical impedance tomography in following up skin conductivity change for different sonophoresis conditions

Sonophoresis is the using of ultrasound waves to increase the entrancement of genes and drugs surpassing the skin barrier. Many mechanisms have been described to illustrate the sonophoresis mode of action; some describe changes in skin resistance during sonophoresis. Electrical impedance tomography (EIT) technique uses voltage measurement through a group of electrodes and reconstructs the data to a conductivity picture. The aim of this work is to evaluate the possibility of using EIT in order to detect changes in mice skin conductivity under pulsed ultrasound waves with powers of 1 and 3 W/cm2 and times of exposure of 2, 4, and 6 min. EIT system was designed and performed locally. The mice skin was obtained from ten albino mice. Immediately after the skin part was exposed to certain sonophoretic condition, its complex biological impedance was measured using the EIT device. The resultant pictures then were analysed using special software. The results indicate that EIT can be used as a good technique for skin conductivity scan. The data analysis shows that as the ultrasound power increases, the skin conductivity increases. However, there is no significant decrease in skin impedance with time in the same ultrasound power at the time range used. Key words: Electrical impedance tomography (EIT), sonophoresis, skin conductivity.

From the age of the pyramids to the superfast world–what has changed in the management of spinal injuries?

Spinal cord injury (SCI) can be life changing and is associated with a variable prognosis. The descriptions of symptoms of the injury are as old as the pyramids, probably among the earliest case records are from the Edwin Smith Surgical papyrus that dates back to 2500‐3500 BC. In that day and age it was considered ‘an ailment not to be cured [treated]’. However, in the 21st century things are viewed differently. The quality of life, morbidity, mortality and participation in employment and sports following spinal injuries have been revolutionised by understanding the pathology and setting standards and principles of management of care pioneered by Sir Ludwig Guttmann during the second world war who established the first spinal injuries centre at Stoke Mandeville in 1944. The principles have been replicated all over the world and have led to much improved outcomes in patients with spinal injuries. The current annual incidence of spinal injuries in the UK is 10‐15 per million population. 1 A symposium was organised a tribute to the last student of Sir Ludwig Guttmann, Professor Wagih Shafik El-Masri on as his 65th birthday. This was organised by his colleagues at the Midlands Centre for Spinal Injuries, Robert Jones and Agnes Hunt Orthopaedic Hospital and attended by 150 delegates (colleagues and friends of Professor El Masri). Guest speakers were invited from various parts of the world. The forum discussed various important learning points and observations from eminent professors in the field of spinal injuries where there is a dearth of level 1 evidence in many aspects of care. This forum also discussed various research projects on the horizon. The need for improved standards of SCI training across Europe was also highlighted. Professor Hans Frankel, an eminent neurologist from Stoke Mandeville discussed his ideas and the origins of the Frankel classification which is widely used in the classification of neurological deficit in SCI. 2 The Medical Research Council (MRC) scale was ordinal only and failed to demonstrate the functional deficit. His classification eliminated observer bias by recording functional abilities, though today, the version used in day-to-day practice tends to be the ASIA scale of impairment which also includes sacral sparing on initial examination. He also opined that regular digital per rectal examination may not add more information than performing a perineal pin prick examination. He concluded that in his experience, managing spinal injuries is easy but not simple. He suggested that electrical perceptual threshold based on skin resistance is the quantitative way of measuring sensation though currently this is mainly used for research purposes. 3

A Device for the Skin–Contact Thermal Resistance Measurement

The skin-contact thermal resistance is a parameter that allows evaluating, in steady condition, the heat flow at the interface between the skin and a rigid surface at a known temperature. At the current state of the art, it is evaluated with empirical equations and is known to be dependent on the contact pressure, on the surface characteristics, and on the skin conductivity. The need to measure skin and contact thermal resistance with low uncertainty led to the realization of the device described in this paper. The instrument - based on the principle of the thermoflowmeter - has been designed with the goal of minimizing the measurement uncertainty with contact temperatures ranging between 12 °C and 27 °C and contact areas from 50 to 314 mm2. The device allows varying and controlling the interface pressure and temperature that, according to existing literature studies, are likely to influence the skin thermal properties. The different temperatures needed for the evaluation of the thermal resistance are measured with individually calibrated thermocouples. The metrological characterization of the flowmeter was performed under vacuum, and the effect of convective heat exchanges in normal operation was modeled and compensated. Measurement repeatability and reproducibility were assessed by measuring the thermal resistance of plastic materials in operational conditions. Preliminary tests showed that the skin-contact thermal resistances measured in different conditions are compatible with the theoretically evaluated ones, with improvement in uncertainty due to direct measurement.

Evaluation of the effectiveness of thoracic sympathectomy in the treatment of primary hyperhidrosis of hands and armpits using the measurement of skin resistance.

IntroductionHyperhidrosis is excessive sweating beyond the needs of thermoregulation. It is disease which mostly affects young people, often carrying a considerable amount of socio-economic implications. Thoracic sympathectomy is now considered to be the "gold standard" in the treatment of idiopathic hyperhidrosis of hands and armpits.AimAssessment of early effectiveness of thoracic sympathectomy using skin resistance measurements performed before surgery and in the postoperative period.Material and methodsA group of 20 patients with idiopathic excessive sweating of hands and the armpit was enrolled in the study. Patients underwent two-stage thoracic sympathectomy with resection of Th2-Th4 ganglions. The skin resistance measurements were made at six previously designated points on the day of surgery and the first day after the operation.ResultsIn all operated patients we obtained complete remission of symptoms on the first day after the surgery. Inhibition of sweating was confirmed using the standard starch iodine (Minor) test. At all measurement points we obtained a statistically significant increase of skin resistance, assuming p < 0.05. To check whether there is a statistically significant difference in the results before and after surgery we used sequence pairs Wilcoxon test.ConclusionsThoracic sympathectomy is an effective curative treatment for primary hyperhidrosis of hands and armpits. Statistically significant increase of skin resistance in all cases is a good method of assessing the effectiveness of the above surgery in the early postoperative period.

Predictive Value of Auricular Diagnosis on Coronary Heart Disease

The ear has a reflexive property; therefore, various physical attributes may appear on the auricle when disorders of the internal organs or other parts of the body exist. Auricular diagnostics is an objective, painless, and noninvasive method that provides rapid access to information. Thus, the association between auricular signals and coronary heart disease (CHD) should be further investigated. A case control study was conducted to determine the predictive value of auricular signals on 100 cases of CHD (CHD+ve = 50; CHD−ve = 50) via visual inspection, electrical skin resistance measurement, and tenderness testing. The results showed that the presence of an ear lobe crease (ELC) was significantly associated with coronary heart disease. The “heart” zone of the CHD+ve group significantly exhibited higher conductivity on both ears than that of the controls. The CHD+ve group experienced significant tenderness in the “heart” region compared with those in the CHD−ve group in both acute and chronic conditions. Further studies that take into consideration the impact of age, race, and earlobe shape on ELC prevalence in a larger sample should be done.