IntroductionPulsed electromagnetic field (PEMF) induces pulsed electric field, which presumably increases membrane permeabilization of the exposed cells, similar to the conventional electroporation. Thus, contactless PEMF could represent a promising approach for drug delivery.Materials and methodsNoninvasive electroporation was performed by magnetic field pulse generator connected to an applicator consisting of round coil. Subcutaneous mouse B16F10 melanoma tumors were treated with intravenously injection of cisplatin (CDDP) (4 mg/kg), PEMF (480 bipolar pulses, at frequency of 80 Hz, pulse duration of 340 μs) or with the combination of both therapies (electrochemotherapy − PEMF + CDDP). Antitumor effectiveness of treatments was evaluated by tumor growth delay assay. In addition, the platinum (Pt) uptake in tumors and serum, as well as Pt bound to the DNA in the cells and Pt in the extracellular fraction were measured by inductively coupled plasma mass spectrometry.ResultsThe antitumor effectiveness of electrochemotherapy with CDDP mediated by PEMF was comparable to the conventional electrochemotherapy with CDDP, with the induction of 2.3 days and 3.0 days tumor growth delay, respectively. The exposure of tumors to PEMF only, had no effect on tumor growth, as well as the injection of CDDP only. The antitumor effect in combined treatment was related to increased drug uptake into the electroporated tumor cells, demonstrated by increased amount of Pt bound to the DNA. Approximately 2-fold increase in cellular uptake of Pt was measured.ConclusionsThe obtained results in mouse melanoma model in vivo demonstrate the possible use of PEMF induced electroporation for biomedical applications, such as electrochemotherapy. The main advantages of electroporation mediated by PEMF are contactless and painless application, as well as effective electroporation compared to conventional electroporation.
Sonoporation is a phenomenon where ultrasound increases cell membrane permeability. As the result, molecules that are otherwise deprived of transport mechanisms can be transported across the cell membrane. Several different experimental exposure systems are described in the literature. Low-frequency ultrasound (<500 kHz) exposure systems can be divided into two groups: systems with the transducer directly immersed in the cell suspension and systems with the transducer in a water bath. We developed an experimental system based on progressive ultrasound wave in a water bath. It consists of a transducer operating at 29.6 kHz submerged in a water bath, and bath walls lined by ultrasound absorbing lining. Using a hydrophone, we evaluated ultrasound reflections inside the bath, both with and without acoustic lining on the bath's boundaries. We also built a finite element model of the system in order to calculate ultrasound parameters that are inaccessible by conventional hydrophone measurement due to equipment limitations. The experimental system will enable exposure of cells to pre-measured and pre-calculated ultrasound conditions.
Ipavec, M, Grapar Žargi, T, Jelenc, J, and Kacin, A. Efficiency of pneumatic tourniquet cuff with asymmetric pressure distribution at rest and during isometric muscle action. J Strength Cond Res XX(X): 000-000, 2018-The aim of this study was to compare effects of newly designed double-chamber cuff with asymmetric pressure (APC) distribution and standard single-chamber cuff with symmetric pressure (SPC) distribution on muscle perfusion and volitional activation. First, the 2 cuffs were compared bilaterally on resting thigh muscles of 17 healthy volunteers at 4 cuff pressures (120, 160, 200, and 240 mm Hg). Then, the subjects performed the isometric endurance test of knee extensor muscles to volitional failure at 40% of maximal volitional isometric action in both free-flow and blood flow restricted condition. Changes in hemoglobin kinetics in vastus lateralis muscle (near-infrared spectroscopy), surface electromyography of vastus medialis muscle, and pain intensity (visual analogue scale [VAS]) were continuously recorded. At rest, a significant difference (p = 0.009) in velocity of change in total hemoglobin concentration was noted between the cuffs at 160 mm Hg (APC = 0.028 μM·s and SPC = 0.056 μM·s). The VAS scores significantly increased (p = 0.031) at pressures ≥200 mm Hg, with no difference between the cuffs. Duration of isometric action with blood flow restriction was 12% shorter (p = 0.003) than in free-flow condition, with no difference between the cuffs. There were no significant differences in muscle activation or hemoglobin kinetics between the exercise conditions or cuff types. The results show that APC reduces blood flow in quadriceps femoris muscle at rest at lower pressure than SPC, which suggests its enhanced efficiency for blood flow restriction. Given that application of either type of cuff during sustained isometric action had only minor impact on muscle endurance and oxygen kinetics, future research must focus primarily on dynamic muscle actions.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.