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EM behavior when the wavelength is large compared to the object size
Published in James R. Nagel, Cynthia M. Furse, Douglas A. Christensen, Carl H. Durney, Basic Introduction to Bioelectromagnetics, 2018
James R. Nagel, Cynthia M. Furse, Douglas A. Christensen, Carl H. Durney
PEMFs are also used for a wide variety of needleless drug delivery applications. Iontophoresis is a method to electrically force drugs across a transdermal interface using a relatively small voltage (0.1–10 V) across the skin boundary. This method appears not to create structural changes in the cells or the skin, but rather just creates ion pathways that a conductive fluid (drug) will follow through preexisting aqueous pathways. At present, a limited number of drugs can be delivered in this method. This method has been extended to a relatively new cancer treatment called electrochemotherapy, which has been used for a variety of cutaneous tumors, including head and neck tumors, melanomas, superficial breast cancer lesions, and so on. In this therapy, the resistance of malignant cells to penetration by certain chemotherapeutic agents is temporarily lowered by electroporation, which creates temporary pores (pathways) in the membranes of the malignant cells by the application of short DC pulses that generate electric fields of several kilovolts per centimeter. Once the cells are porated, the chemotherapeutic agents can enter the malignant cells and destroy them. Electrochemotherapy can not only increase the efficacy of certain chemotherapeutic agents but also reduce side effects because malignant cells can be destroyed with much lower doses of chemotherapeutic agents than with conventional systemic chemotherapy. This method is fundamentally different from hyperthermia (heating) combined with chemotherapy, which is described in Chapter 6.
Radio-Electro-Chemotherapy of Cancer: New Perspectives for Cancer Treatment
Published in Pandit B. Vidyasagar, Sagar S. Jagtap, Omprakash Yemul, Radiation in Medicine and Biology, 2017
Pratip Shil, Pandit B. Vidyasagar, Kaushala Prasad Mishra
With the advancement in electronics, many companies are manufacturing electroporators of different specifications. Today, the most frequent application of electroporation is transfection of cells, involving the cellular uptake of DNA molecules. Also, this technology is used for the introduction of fluorescent probes into cells, electroloading of drugs, and transportation of molecules into the cells, etc. The applications have been extended to cancer research as well. This resulted in the emergence of a branch of therapeutics called electrochemotherapy (ECT), where the electric pulses are used to permeabilize the cell membrane and enhance the uptake of the molecules [34–35]. Electrochemotherapy is focused on three aspects: (i) electroporation of cells in living tissues, (ii) potentiation of cytotoxic drugs that are nonpermeant to cells, and (iii) intrinsic response of the body systems, i.e., immune response and blood flow patterns of the patient.
Analysis of membrane permeability due to synergistic effect of controlled shock wave and electric field application
Published in Electromagnetic Biology and Medicine, 2020
Shadeeb Hossain, Ahmed Abdelgawad
Comparative studies between different technologies can be an effective methodology to realize the changes in the membrane permeability under perturbation. An important factor for sonoporation involves the application of high-frequency alternating waves in the range of MHz and can contribute to excessive heating and tissue tear at high amplitudes. Radiofrequency (RF) treatment, similarly causes excessive Joule heating under-prolonged exposure time. Cryosurgery, which involves freezing the tumor cells might not be an effective method when combined with chemotherapeutic drugs (https://www.healthline.com/health/cryosurgery#risks). In contrast, electrochemotherapy is an effective clinical treatment for certain types of cancer cells (Cadossi et al. 2014; Hofmann et al. 1999; Okino and Mohri 1987). Controlled shock waves, on the other hand, can be directed for an effective treatment of deep tissue or malignant cells without severely affecting the surrounding healthy or normal neighboring cells (http://eswt.net/how-do-shock-waves-differ-to-ultrasound).
Updated standard operating procedures for electrochemotherapy of cutaneous tumours and skin metastases
Published in Acta Oncologica, 2018
Julie Gehl, Gregor Sersa, Louise Wichmann Matthiessen, Tobian Muir, Declan Soden, Antonio Occhini, Pietro Quaglino, Pietro Curatolo, Luca G. Campana, Christian Kunte, A. James P. Clover, Giulia Bertino, Victor Farricha, Joy Odili, Karin Dahlstrom, Marco Benazzo, Lluis M. Mir
Due to the dramatic increase in cytotoxicity, electrochemotherapy is effective in all solid tumours, as reported so far; melanoma, adenocarcinoma (breast or other), basal cell carcinoma, squamous cell carcinoma, sarcomas, and other solid tumour malignancies. Electrochemotherapy is a local treatment, and after drug administration the treatment area must be uniformly covered by an adequate electric field, a consideration similar to surgical approaches. Throughout the published literature remarkably consistent responses have been reported, with an approximately 80% OR (objective response rate) including all tumour histologies, and approximately 60–70% CR (complete remission) rate after once-only treatment [6,8,10,12,13,15–17,19,20]. These results were demonstrated on tumours smaller than 3 cm in diameter after single electrochemotherapy session, and although bigger tumours have somewhat lower response rates, these remain high [8,9,11,21]. Electrochemotherapy may be repeated, in case of progression or in cases where tumour remains.
Antitumor efficacy of liposome-encapsulated NVP-BEZ 235 in combination with irreversible electroporation
Published in Drug Delivery, 2018
Li Tian, Yang Qiao, Patrick Lee, Lucas Wang, Ashley Chang, Saisree Ravi, Thomas A. Rogers, Linfeng Lu, Burapol Singhana, Jun Zhao, Marites P. Melancon
Electrochemotherapy is a new technique that combines conventional chemotherapy with cell-membrane electroporation to enhance the transport of chemotherapy drugs into cells (Belehradek et al., 1993). Studies showed that intracellular drug concentrations increased by 300- to 700-fold in electroporated cells (Saczko et al., 2014) and that drug concentrations can remain elevated in the tumor area for several hours (Jarm et al., 2010). Nanoparticles are promising carriers for chemotherapy agents because of their many advantages over bare small molecules (Blanco et al., 2015). Nanoparticle-based treatments require less frequent dosing because they are generally more bioavailable than are standard agents (Gelperina et al., 2005). Chemotherapy agents delivered with nanoparticles have also been shown to have enhanced anticancer and fewer side effects than small molecular chemotherapy agents because they take advantage of the enhanced permeation and retention effect, which utilizes the leaky vessels and damaged lymphatic drainage in the tumor area and allows the accumulate of nanoparticles and the incorporation of targeting ligands, which allows specific targeting of the nanoparticles to tumor cells (Blanco et al., 2015). Finally, nanoparticles have potential theranostic applications, especially in combination with other clinical or interventional modalities (Tian et al., 2016).