Biofilm on total joint replacement materials can be reduced through electromagnetic induction heating using a portable device.

BACKGROUND: Periprosthetic joint infection is a serious complication following joint replacement. The development of bacterial biofilms bestows antibiotic resistance and restricts treatment via implant retention surgery. Electromagnetic induction heating is a novel technique for antibacterial treatment of metallic surfaces that has demonstrated in-vitro efficacy. Previous studies have always employed stationary, non-portable devices. This study aims to assess the in-vitro efficacy of induction-heating disinfection of metallic surfaces using a new Portable Disinfection System based on Induction Heating. METHODS: Mature biofilms of three bacterial species: S. epidermidis ATCC 35,984, S. aureus ATCC 25,923, E. coli ATCC 25,922, were grown on 18 × 2 mm cylindrical coupons of Titanium-Aluminium-Vanadium (Ti6Al4V) or Cobalt-chromium-molybdenum (CoCrMo) alloys. Study intervention was induction-heating of the coupon surface up to 70ºC for 210s, performed using the Portable Disinfection System (PDSIH). Temperature was monitored using thermographic imaging. For each bacterial strain and each metallic alloy, experiments and controls were conducted in triplicate. Bacterial load was quantified through scraping and drop plate techniques. Data were evaluated using non-parametric Mann-Whitney U test for 2 group comparison. Statistical significance was fixed at p ≤ 0.05. RESULTS: All bacterial strains showed a statistically significant reduction of CFU per surface area in both materials. Bacterial load reduction amounted to 0.507 and 0.602 Log10 CFU/mL for S. aureus on Ti6Al4V and CoCrMo respectively, 5.937 and 3.500 Log10 CFU/mL for E. coli, and 1.222 and 0.372 Log10 CFU/mL for S. epidermidis. CONCLUSIONS: Electromagnetic induction heating using PDSIH is efficacious to reduce mature biofilms of S aureus, E coli and S epidermidis growing on metallic surfaces of Ti6Al4V and CoCrMo alloys.

Preliminary evaluation of the safety and efficacy of glucose solution infusion through the hepatic artery on irreversible electroporation focusing.

Due to electrical features of the tissue, such as impedance, which have a significant impact on irreversible electroporation (IRE) function, the administration of glucose solution 5% (GS5%) through the hepatic artery would focus IRE on scattered liver tumors. By creating a differential impedance between healthy and tumor tissue. This study aimed to determine the effects of the GS5% protocol on healthy liver tissue and its safety. 21 male Athymic nude rats Hsd: RH-Foxn1mu were used in the study. Animals were split into two groups. In group 1, a continuous infusion through the gastroduodenal artery of GS5% was performed to measure the impedance with a dose of 0.008 mL/g for 16 min. In group 2, the animals were divided into two subgroups for infusions of GS5%. Group 2.1, at 0.008 mL/g for 16 min. Group 2.2 at 0.03 mL/g for 4 min. Blood samples were collected after anesthesia has been induced. The second sample, after catheterization of the artery, and the third after the GS5% infusion. All the animals were sacrificed to collect histological samples. The survival rate during the experiment was 100%. A considerable impact on the impedance of the tissue was noticed, on average up to 4.31 times more than the baseline, and no side effects were observed after GS5% infusion. In conclusion, impedance alteration by Glucose solution infusion may focus IRE on tumor tissue and decrease IRE's effects on healthy tissue.

Liver tissue remodeling following ablation with irreversible electroporation in a porcine model.

Irreversible electroporation (IRE) is a method of non-thermal focal tissue ablation characterized by irreversibly permeabilizing the cell membranes while preserving the extracellular matrix. This study aimed to investigate tissue remodeling after IRE in a porcine model, especially focusing on the extracellular matrix and hepatic stellate cells. IRE ablation was performed on 11 female pigs at 2,000 V/cm electric field strength using a versatile high-voltage generator and 3 cm diameter parallel-plate electrodes. The treated lobes were removed during surgery at 1, 3, 7, 14, and 21 days after IRE. Tissue remodeling and regeneration were assessed by histopathology and immunohistochemistry. Throughout the treated area, IRE led to extensive necrosis with intact collagenous structures evident until day 1. From then on, the necrosis progressively diminished while reparative tissue gradually increased. During this process, the reticulin framework and the septal fibrillar collagen remained in the necrotic foci until they were invaded by the reparative tissue. The reparative tissue was characterized by a massive proliferation of myofibroblast-like cells accompanied by a complete disorganization of the extracellular matrix with the disappearance of hepatic architecture. Hepatic stellate cell markers were associated with the proliferation of myofibroblast-like cells and the reorganization of the extracellular matrix. Between 2 and 3 weeks after IRE, the lobular architecture was almost completely regenerated. The events described in the present study show that IRE may be a valid model to study the mechanisms underlying liver regeneration after extensive acute injury.

Real-Time Impedance Monitoring During Electroporation Processes in Vegetal Tissue Using a High-Performance Generator.

Classical application of electroporation is carried out by using fixed protocols that do not clearly assure the complete ablation of the desired tissue. Nowadays, new methods that pursue the control of the treatment by studying the change in impedance during the applied pulses as a function of the electric field are being developed. These types of control seek to carry out the treatment in the fastest way, decreasing undesired effects and treatment time while ensuring the proper tumour ablation. The objective of this research is to determine the state of the treatment by continuously monitoring the impedance by using a novel versatile high-voltage generator and sensor system. To study the impedance dynamics in real time, the use of pulses of reduced voltage, below the threshold of reversible electroporation, is tested to characterise the state-of-the-treatment without interfering with it. With this purpose, a generator that provides both low voltage for sense tissue changes and high voltage for irreversible electroporation (IRE) was developed. In conclusion, the characterisation of the effects of electroporation in vegetal tissue, combined with the real-time monitoring of the state-of-the-treatment, will enable the provision of safer and more effective treatments.

Successful Tumor Electrochemotherapy Using Sine Waves.

OBJECTIVE: The purpose of this work is to assess the ability of sine waves to perform electrochemotherapy (ECT) and to study the dependence of the frequency of the applied sine wave on the treatment efficacy. METHODS: A subcutaneous tumor model in mice was used, and the electric field was delivered in combination with bleomycin. Sinusoidal electric fields of different frequencies, amplitudes, and durations were compared to square waves. Computer simulations were additionally performed. RESULTS: The results confirmed the ability of a sinusoidal electric field to obtain successful ECT responses. A strong dependence on frequency was obtained. The efficacy of the treatment decreased when the frequency of the sine waves was increased. At low sinusoidal frequency, the efficacy of the treatment is very similar to that obtained with a square wave. The collateral effects such as skin burns and muscle contractions decreased for the highest frequency assayed. CONCLUSION: The use of sine wave burst represents a feasible option for the treatment of cancer by ECT. SIGNIFICANCE: These results could have important implications for the treatment of cancer in the clinical world where ECT is performed with dc square pulses.