194 research outputs found
Electropermeabilization of inner and outer cell membranes with microsecond pulsed electric field. Quantitative study with calcium ions
Microsecond pulsed electric fields (mu sPEF) permeabilize the plasma membrane (PM) and are widely used in research, medicine and biotechnology. For internal membranes permeabilization, nanosecond pulsed electric fields (nsPEF) are applied but this technology is complex to use. Here we report that the endoplasmic reticulum (ER) membrane can also be electropermeabilized by one 100 mu s pulse without affecting the cell viability. Indeed, using Ca2+ as a permeabilization marker, we observed cytosolic Ca2+ peaks in two different cell types after one 100 mu s pulse in a medium without Ca2+. Thapsigargin abolished these Ca2+ peaks demonstrating that the calcium is released from the ER. Moreover, IP3R and RyR inhibitors did not modify these peaks showing that they are due to the electropermeabilization of the ER membrane and not to ER Ca2+ channels activation. Finally, the comparison of the two cell types suggests that the PM and the ER permeabilization thresholds are affected by the sizes of the cell and the ER. In conclusion, this study demonstrates that mu sPEF, which are easier to control than nsPEF, can permeabilize internal membranes. Besides, mu sPEF interaction with either the PM or ER, can be an efficient tool to modulate the cytosolic calcium concentration and study Ca2+ roles in cell physiology
Electroporation in cancer treatment: the antitumor electrochemotherapy
Electrochemotherapy (ECT) is a novel anticancer therapy, combining the delivery of electric impulses,
which increase cellmembrane permeability, with that of cytotoxic drugs that normally penetrate poorly
into cells, and whose activity is thus potentiated. After several years of development of the concept,
instrumentation and operational procedures, ECT is now being used increasingly in human medicine.
Veterinary clinical studies have shown the efficacy of this approach in the treatment of solid
tumours in cats, dogs and horses. As it is effective, easy to use, has no side effects and is inexpensive,
the use of ECT is expected to expand in veterinary clinical practice as well. ECT concept, bases, and
outcomes in canidae, felidae and equidae are reported in this communication.L'électrochimiothérapie (ECT)
est une nouvelle approche de traitement antitumoral: elle associe l'application d'impulsions
électriques qui augmentent la perméabilité de la membrane cellulaire, à l'administration de
médicaments cytotoxiques qui pénÚtrent difficilement dans les cellules; leur activité est
ainsi potentialisée. AprÚs quelques années de développement du concept, de l'instrumentation
et des procédures opérationnelles, l'ECT est en train de se répandre en clinique humaine.
Des études en clinique vétérinaire montrent l'efficacité de cette approche dans le
traitement de tumeurs solides chez les chats, les chiens et les équidés. De par son
efficacité, sa facilité d'application, son absence d'effets secondaires et son coût réduit,
l'ECT devrait aussi se répandre dans la pratique clinique vétérinaire. Son concept, ses
bases et les résultats obtenus chez les canidés, félidés et équidés sont rapportés dans
cette communication
Introduction to Fifth Special Issue on Electroporation-Based Technologies and Treatments
This special issue of the Journal of Membrane Biology contains reports on recent developments in the field of electroporation by participants in the International Workshop and Postgraduate Course on Electroporation-Based Technologies and Treatments held in November 2014 in Ljubljana. This was the eighth session of what is now an annual event, first organized in 2003
Veterinary Guidelines for Electrochemotherapy of Superficial Tumors
Electrochemotherapy (ECT) consists in the application of electric pulses to increase chemotherapeutic drug intake (bleomycin, cisplatin, or calcium) into the tumor cells. It has become a very valuable treatment option in veterinary oncology. It is an effective and safe treatment modality, which is not only beneficial as a palliative treatment, but also for a curative approach. Performing the treatment adequately will ensure the best results possible, in the minimum number of sessions, and reduce complications. Usually, only one session is enough to achieve excellent results, but the treatment can be repeated. Several sessions can be necessary in the case of incompletely treated or very extended lesions, as well as in the occurrence of new lesions. ECT is effective for superficial or oral tumors of any histology that are accessible to the electrodes. Intravenous bleomycin is the preferred drug and route of administration, leaving other ways of administration and drugs for selected cases. The guidelines presented here are destined to veterinarians who want to develop their understanding of the basis of ECT and wish to perform it adequately and effectively. In this paper, we also discuss common problems and how to solve them, and we include practical tips to improve the treatment results based on common questions and mistakes of beginner users.Fil: Tellado, MatĂas. No especifĂca;Fil: Mir, Lluis M.. No especifĂca;Fil: Maglietti, Felipe Horacio. Hospital Italiano; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; Argentin
Technological and theoretical aspects for testing electroporation on liposomes
Recently, the use of nanometer liposomes as nanocarriers in drug delivery systems mediated by nanoelectroporation has been proposed. This technique takes advantage of the possibility of simultaneously electroporating liposomes and cell membrane with 10-nanosecond pulsed electric fields (nsPEF) facilitating the release of the drug from the liposomes and at the same time its uptake by the cells. In this paper the design and characterization of a 10 nsPEF exposure system is presented, for liposomes electroporation purposes. The design and the characterization of the applicator have been carried out choosing an electroporation cuvette with 1 mm gap between the electrodes. The structure efficiency has been evaluated at different experimental conditions by changing the solution conductivity from 0.25 to 1.6 S/m. With the aim to analyze the influence of device performances on the liposomes electroporation, microdosimetric simulations have been performed considering liposomes of 200 and 400 nm of dimension with different inner and outer conductivity (from 0.05 to 1.6 S/m) in order to identify the voltage needed for their poration
Introduction to Fourth Special Issue on Electroporation-Based Technologies and Treatments
This fourth special electroporation-based technologies and treatments issue of the Journal of Membrane Biology contains reports on recent developments in the field of electroporation by participants in the 7th International Workshop and Postgraduate Course on electroporation based technologies and treatments (EBTT 2013) held in Ljubljana, November 17â23, 2013. The 65 participants included faculty members, invited lecturers, special guests, and young scientists, and students from 16 countries. In addition to lectures on the fundamentals, this yearâs sessions included talks on microbial inactivation by pulsed electric fields, modeling of intracellular electroporation, electroporation in food processing, and electrotransfer-facilitated DNA vaccination
Effects of dimethyl sulfoxide in cholesterol-containing lipid membranes: a comparative study of experiments in silico and with cells
Dimethyl sulfoxide (DMSO) has been known to enhance cell membrane permeability of drugs or DNA. Molecular dynamics (MD) simulations with single-component lipid bilayers predicted the existence of three regimes of action of DMSO: membrane loosening, pore formation and bilayer collapse. We show here that these modes of action are also reproduced in the presence of cholesterol in the bilayer, and we provide a description at the atomic detail of the DMSO-mediated process of pore formation in cholesterol-containing lipid membranes. We also successfully explore the applicability of DMSO to promote plasma membrane permeability to water, calcium ions (Ca2+) and Yo-Pro-1 iodide (Yo-Pro-1) in living cell membranes. The experimental results on cells in culture can be easily explained according to the three expected regimes: in the presence of low doses of DMSO, the membrane of the cells exhibits undulations but no permeability increase can be detected, while at intermediate DMSO concentrations cells are permeabilized to water and calcium but not to larger molecules as Yo-Pro-1. These two behaviors can be associated to the MD-predicted consequences of the effects of the DMSO at low and intermediate DMSO concentrations. At larger DMSO concentrations, permeabilization is larger, as even Yo-Pro-1 can enter the cells as predicted by the DMSO-induced membrane-destructuring effects described in the MD simulations
Experimental and Theoretical Brownian Dynamics Analysis of Ion Transport During Cellular Electroporation of E. coli Bacteria
Escherichia coli bacterium is a rod-shaped organism composed of a complex
double membrane structure. Knowledge of electric field driven ion transport
through both membranes and the evolution of their induced permeabilization has
important applications in biomedical engineering, delivery of genes and
antibacterial agents. However, few studies have been conducted on Gram-negative
bacteria in this regard considering the contribution of all ion types. To
address this gap in knowledge, we have developed a deterministic and stochastic
Brownian dynamics model to simulate in 3D space the motion of ions through
pores formed in the plasma membranes of E. coli cells during electroporation.
The diffusion coefficient, mobility, and translation time of Ca,
Mg, Na, K, and Cl ions within the pore region are estimated
from the numerical model. Calculations of pore's conductance have been
validated with experiments conducted at Gustave Roussy. From the simulations,
it was found that the main driving force of ionic uptake during the pulse is
the one due to the externally applied electric field. The results from this
work provide a better understanding of ion transport during electroporation,
aiding in the design of electrical pulses for maximizing ion throughput,
primarily for application in cancer treatment.Comment: Annals of Biomedical Engineering, 202
Possible molecular and cellular mechanisms at the basis of atmospheric electromagnetic field bioeffects
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