Galvanic current dosage and bacterial concentration are determinants of the bactericidal effect of percutaneous needle electrolysis: an in vitro study

Percutaneous needle electrolysis (PNE) is a physiotherapy technique that has been shown to be effective in different pathologies such as tendinopathies or mammary fistula. For many years, theoretical bactericidal and germicidal effects have been attributed to this type of galvanic currents, partly explained by the changes in pH that it generates. However, these effects have not yet been demonstrated. The aim of this study was to evaluate the bactericidal effect and the changes in pH caused by PNE. S. aureus were prepared in two different solutions (TSB and saline solution) and in different concentrations (from 9 to 6 Log10 CFU/mL). Bacteria were treated with three experimental PNE doses to assess bacterial death levels and the changes caused to the pH of the medium. The viable cell count showed that all experimental PNE doses had a bactericidal effect against a high concentration (9 Log10 CFU/mL) of S. aureus in saline solution (p < 0.001). Furthermore, we found that when the concentration of bacteria decreased, a lower dose of galvanic current generated the same effect as a higher dose. Changes in pH were registered only in experiments performed with saline solution. PNE had a bactericidal effect against S. aureus and the level of this effect was mainly modulated by the solution, the bacterial concentration and the dose. Changes affecting pH were modulated by the type of solution and there was no relationship between this and bacterial death.

Galvanic current activates the NLRP3 inflammasome to promote type I collagen production in tendon

ABSTRACTThe NLRP3 inflammasome coordinates inflammation in response to different pathogen- and damage-associated molecular patterns, being implicated in different infectious, chronic inflammatory, metabolic and degenerative diseases. In chronic tendinopathies lesions, different non-resolving mechanisms produce a degenerative condition that impairs tissue healing, complicating their clinical management. Percutaneous needle electrolysis consist in the application of a galvanic current and is emerging as a novel treatment for tendinopathies. Here we found that galvanic current activates the NLRP3 inflammasome and the induction of an inflammatory response promoting a collagen-mediated regeneration of the tendon. This study establish the molecular mechanism of percutaneous electrolysis for the treatment of chronic lesions and the beneficial effects of an induced inflammasome-related response.

The Study of Corrosion Behaviors of Carbon Steel Weldments and Their Inhibition in Simulated Pore Solution Using Multi-Electrode Array Technique

A multi-electrode array sensor was developed to study the corrosion behaviors of carbon steel weldments and the effectiveness of the NaNO2 inhibitor in carbonated pore solution. The sensor can simulate a complete weldment, and the measurement results can match well with the coupon immersion test. The galvanic corrosion between the weld area, heat-affected area, and base metal area, as well as the effect of nitrite corrosion inhibitor on the weld area, were observed by measuring the open circuit potential, coupling potential, and galvanic current. The results show that corrosion is likely to happen around the weld metal area and its adjacent heat-affected zone. The intensive galvanic currents can accelerate the localized corrosion, while NaNO2 can inhibit it.

Wave amplitude of embedded ultrasonic transducer-based damage monitoring of concrete due to steel bar corrosion

In this research, four embedded ultrasonic piezoelectric transducers were combined to form cross pair and opposite pair monitoring schemes for continuously monitoring the damage to different strength grades of concrete caused by the corrosion of reinforcements under accelerated corrosion conditions. The damage process was analyzed by combining the electrochemical effects of steel corrosion, that is, half-cell potential and galvanic current tests. Results show that the embedded ultrasonic transducer method can detect damage of concrete during steel corrosion and that each stage of damage can be determined from the plots of ultrasonic transducer data versus corrosion rate. The results further indicate that a combination of cross pair and opposite pair testing methods can more comprehensively reflect the damage to concrete caused by the expansion of corrosion of steel bars, than a single testing method. Since electrochemical testing can only depict the corrosion state of steel rebars, it is beneficial to use embedded ultrasonic measurements to monitor the damage process of concrete. The differences in damage between different strength grades of concrete, that is, the resistance to corrosion of steel bars and brittle failure, can be obtained from the plots of ultrasonic transducer data.

Galvanic Interactions between Fe Electrodes in CO<sub>2 Saturated Solutions with Different pH

Localized CO2 corrosion is a very common problem in the oil and gas industry. Severe damage of the surface is attributed to the formation, and breakdown, of protective iron carbonate (FeCO3) scales. When the corrosion layer is compromised, the difference between the open circuit potential of the FeCO3-covered and non-covered regions act as the driving force for a galvanic interaction. Depending on the area ratio of the anodic and cathodic areas, the surface could suffer severe localized damage. The present study was focused on the galvanic interactions between iron samples in solutions with different pH. CO2 saturated 1% NaCl solutions with bulk pH of between 6 and 8 and temperature ranging from 20°C and 80°C were studied. A split cell allowed for customization of different environments in each of the half cells, along with simultaneous monitoring of the galvanic current and driving force as indicated by the difference in open circuit potential. Corrosion product layers were characterized using scanning electron microscopy, energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. The results indicated that the pH of the bulk solution plays a major role in the formation of protective FeCO3 scales. Fe exhibited passive-like behavior when immersed in a solution at 80°C with pH adjusted to 8. After reaching a passive-like behavior, Fe samples were cathodic when coupled to samples immersed in a solution with lower pH. The galvanic current decreased with increasing temperature and pH gradient.

Microstructure and Properties of SUS304 Stainless Steel Joints Brazed with Electrodeposited Ni-Cr-P Alloy Coatings

In this study, an amorphous Ni-13.4Cr-11.6P (mass%) alloy coating with a thickness of 30 μm was deposited on the surface of SUS304 stainless steel as a brazing filler metal to conduct brazing. The differential thermal analysis measurements indicate that the electrodeposited Ni-13.4Cr-11.6P alloy has a melting point of approximately 892 °C, which is almost consistent with that of the commercial BNi-7 filler metal. The microstructure, shear strength, and fracture mode of the brazed joint were investigated using an electron probe X-ray microanalyzer, a scanning electron microscope, an optical microscope, and a universal testing machine. The results showed that the brazed filler metal is filled between the SUS304 stainless steel plates without any flaws in the brazed seam. The P-containing phases, i.e., the Cr-P rich phase and the (Ni,Fe)3P phase, were formed in the brazed seam. The shear strength of the brazed joint obtained in this study is 59.0 MPa. The fracture occurs in the brazed filler zone, where the brittle P-containing phases are present. Galvanic current measurement results showed that the brazed Ni-13.4Cr-11.6P alloy coating has a better corrosion resistance than that of the brazed Ni-11P alloy coating, which can be attributed to the formation of a large amount of Ni-Fe solid solution and Cr-P rich phase in the top layer of the brazed Ni-13.4Cr-11.6P alloy coating.

Effect of Cathodic Polarisation Switch-Off on the Passivity and Stability to Crevice Corrosion of AISI 304L Stainless Steel

The effects of cathodic polarisation switch-off on the passivation of AISI 304L stainless steel in air and its crevice corrosion susceptibility in 3.5 wt.% NaCl aqueous electrolyte were investigated. Scanning Kelvin probe (SKP) data showed that the oxide film is significantly destabilised and the rate of steel passivation in air is slowed down. Thermal desorption analysis (TDA) highlighted that hydrogen absorption is proportional to the applied cathodic current density. A special crevice corrosion set-up was designed to realise simultaneous reproducible monitoring of potential and galvanic current to study the impact of prior cathodic polarisation on crevice corrosion onset.

Safety analysis of percutaneous needle electrolysis: a study of needle composition, morphology, and electrical resistance

Background: Percutaneous needle electrolysis (PNE) consists of a galvanic current combined with the insertion of a solid needle into the tissues of the musculoskeletal system. The application of a galvanic current through a needle can alter the morphology and composition during treatment application. This procedure may also provoke a localized temperature increase. Aim: The aim was to evaluate the safety of the PNE procedure by analyzing possible alterations of the needles employed. Methods: Physio Invasiva® and AguPunt EPI® brand needles, commonly used for the application of this technique, were analyzed in response to three different treatment protocols. Temperature changes were evaluated with the needles immersed in a test tube containing Ringer’s solution, and electrical resistance was evaluated with a multimeter. The morphology of the needles, pre- and post-treatment, was examined with a scanning electron microscope (FEI Quanta 600), and the composition of the needles was evaluated using RX diffusion with Oxford Instruments software. Results: Ringer’s solution contained in the test tubes examined did not present temperature changes. No changes were observed in the needles under investigation with respect to electrical resistance, morphology, or composition with a protocol applying 3-mA intensity for 3 s and three applications. However, important morphological alterations were observed that affected needle composition after 50 applications (at 3 mA for 3 s). Conclusion: PNE, applied according to conventional protocols, appeared to be safe and athermal, and did not provoke a loss of metal particles or modify the morphology of the needles used when studied in vitro.

Modification of Patients’ Sensitivity to Galvanic Current After the Administered Systemic Cryotherapy

Aim: The purpose of the study was to evaluate the sensitivity of patients to galvanic current after systemic cryotherapy. Material and Methods: Study group: 77 physiotherapists – hospital employees, aged 21-64 (AVG 29.4±9.5). The sensitivity was evaluated four times: before and immediately after the systemic cryotherapy procedure (1 session, 2 minutes, temperature -120°C), after exercising on a vertical cycle ergometer (20 minutes) and 4 hours after the procedure. The intensity of the galvanic current, which caused a slight tingling, was recorded. Two electrode placements were used: longitudinal on the upper limbs and transverse over the knee joints. Results: Statistical analysis revealed that the mean sensitivity to the galvanic current measured on both upper limbs or over the knee joints increases statistically significantly after systemic cryotherapy treatments. This effect persists even after 4 hours (Friedman’s ANOVA, p<0.001). Statistically significant increases in sensitivity to galvanic current were found compared to initial values for each pair of measurements, irrespective of electrode placement and test position (Wilcoxon test, p<0.01). The increase in sensitivity according to the measuring position concerned 68.8; 63.6; 72.7% of the participants on the left upper limb, on the right 61.0; 68.8; 74.0%, over the left knee joint 61.0; 68.8; 72.7% and over the right 58.4, 75.3 and 80.5% of the subjects in the study group. Conclusions: 1. After the administered systemic cryotherapy, sensitivity to galvanic current increases in most patients. 2. The increase in sensitivity to galvanic current depends on the time difference between treatments and is individually variable.

Percutaneous Needle Electrolysis Reverses Neurographic Signs of Nerve Entrapment by Induced Fibrosis in Mice

Nerve entrapments such as carpal tunnel syndrome are the most common mononeuropathies. The lesional mechanism includes a scarring reaction that causes a vascular compromise. The most effective treatment is surgery, which consists of removing the scarred area, thus reverting the vascular impairment. In the present study, a more conservative therapeutic approach has been undertaken to release the nerve by means of galvanic current (GC) applied with a needle: percutaneous needle electrolysis (PNE). For this purpose, a mouse model of sciatic nerve entrapment has been created using albumin coagulated by glutaraldehyde (albumin 35% and glutaraldehyde 2% volume applied, 10 μl). After two weeks, a fibrous reaction was obtained which entrapped the nerve to the extent of causing atrophy of the leg musculature (14.7%, P < 0.05 compared to the control leg). Ultrasound imaging confirmed that the model’s image was compatible with that of nerve entrapment in patients. To quantify the degree of entrapment, nerve conduction recordings were made. The amplitude (peak-to-peak) of the compound muscle action potential (CMAPs) decreased by 32.2% ( P < 0.05 ), and the proximal latency increases by 17.7% ( P < 0.05 , in both cases). In order to release the sciatic nerve, PNE was applied (1.5 mA for 3 seconds and 3 repetitions; 1.5/3/3) by means of a solid needle in the immediacy of perineural fibrosis before and 5 minutes after the application of GC, and the proximal latency shows a decrease of 16% ( P < 0.05 ). The recovery of CMAPs amplitude was about 48.7% ( P < 0.05 ). Three weeks later, the CMAPs amplitude was almost completely recovered (94.64%). Therefore, with the application of GC by means of a solid needle, the sciatic nerve was definitively released from its fibrous entrapment.