Electroporation is the phenomenon that occurs when a cell is exposed to a high electric field, which causes transient cell membrane permeabilization. A paramount electroporation-based application is electrochemotherapy, which is performed by delivering high-voltage electric pulses that enable the chemotherapeutic drug to more effectively destroy the tumor cells. Electrochemotherapy can be used for treating deep-seated metastases (e.g. in the liver, bone, brain, soft tissue) using variable-geometry long-needle electrodes. To treat deep-seated tumors, patient-specific treatment planning of the electroporation-based treatment is required. Treatment planning is based on generating a 3D model of the organ and target tissue subject to electroporation (i.e. tumor nodules). The generation of the 3D model is done by segmentation algorithms. We implemented and evaluated three automatic liver segmentation algorithms: region growing, adaptive threshold, and active contours (snakes). The algorithms were optimized using a seven-case dataset manually segmented by the radiologist as a training set, and finally validated using an additional four-case dataset that was previously not included in the optimization dataset. The presented results demonstrate that patient’s medical images that were not included in the training set can be successfully segmented using our three algorithms. Besides electroporation-based treatments, these algorithms can be used in applications where automatic liver segmentation is required.
COBISS.SI-ID: 10019668
This systematic review has two purposes: to consolidate the current knowledge about clinical effectiveness of electrochemotherapy, a highly effective local therapy for cutaneous and subcutaneous tumors; and to investigate the differences in effectiveness of electrochemotherapy with respect to tumor type, chemotherapeutic drug, and route of drug administration. All necessary steps for a systematic review were applied: formulation of research question, systematic search of literature, study selection and data extraction using independent screening process, assessment of risk of bias, and statistical data analysis using two-sided common statistical methods and meta-analysis. Studies were eligible for the review if they provided data about effectiveness of singlesession electrochemotherapy of cutaneous or subcutaneous tumors in various treatment conditions. In total, 44 studies involving 1894 tumors were included in the review. Data analysis confirmed that electrochemotherapy had significantly (p ( .001) higher effectiveness (by more than 50%) than bleomycin or cisplatin alone. The effectiveness was significantly higher for intratumoral than for intravenous administration of bleomycin (p ( .001 for CR%, p Ľ .028 for OR%). Bleomycin and cisplatin administered intratumorally resulted in equal effectiveness of electrochemotherapy. Electrochemotherapy was more effective in sarcoma than in melanoma or carcinoma tumors. The results of this review shed new light on effectiveness of electrochemotherapy and can be used for prediction of tumor response to electrochemotherapy with respect to various treatment conditions and should be taken into account for further refinement of electrochemotherapy protocols.
COBISS.SI-ID: 9569364
Electrofusion is an efficient method for fusing cells using short-duration high-voltage electric pulses. However, electrofusion yields are very low when fusion partner cells differ considerably in their size, since the extent of electroporation (consequently membrane fusogenic state) with conventionally used microsecond pulses depends proportionally on the cell radius. We here propose a new and innovative approach to fuse cells with shorter, nanosecond (ns) pulses. Using numerical calculations we demonstrate that ns pulses can induce selective electroporation of the contact areas between cells (i.e. the target areas), regardless of the cell size. We then confirm experimentally on B16-F1 and CHO cell lines that electrofusion of cells with either equal or different size by using ns pulses is indeed feasible. Based on our results we expect that ns pulses can improve fusion yields in electrofusion of cells with different size, such as myeloma cells and B lymphocytes in hybridoma technology.
COBISS.SI-ID: 10300500
Phylogenetic studies show that horizontal gene transfer (HGT) is a significant contributor to genetic variability of prokaryotes, and was perhaps even more abundant during the early evolution. Hitherto, research of natural HGT has mainly focused on three mechanisms of DNA transfer: conjugation, natural competence, and viral transduction. This paper discusses the feasibility of a fourth such mechanism — cell electroporation and/or electrofusion triggered by atmospheric electrostatic discharges (lightnings). A description of electroporation as a phenomenon is followed by a review of experimental evidence that electroporation of prokaryotes in aqueous environments can result in release of non-denatured DNA, as well as uptake of DNA from the surroundings and transformation. Similarly, a description of electrofusion is followed by a review of experiments showing that prokaryotes devoid of cell wall can electrofuse into hybrids expressing the genes of their both precursors. Under sufficiently fine-tuned conditions, electroporation and electrofusion are efficient tools for artificial transformation and hybridization, respectively, but the quantitative analysis developed here shows that conditions for electroporation-based DNA release, DNA uptake and transformation, as well as for electrofusion are also present in many natural aqueous environments exposed to lightnings. Electroporation is thus a plausible contributor to natural HGT among prokaryotes, and could have been particularly important during the early evolution, when the other mechanisms might have been scarcer or nonexistent. In modern prokaryotes, natural absence of the cell wall is rare, but it is reasonable to assume that the wall has formed during a certain stage of evolution, and at least prior to this, electrofusion could also have contributed to natural HGT. The concluding section outlines several guidelines for assessment of the feasibility of lightning-triggered HGT.
COBISS.SI-ID: 9931348
Electroporation (EP) is a physicalmethod for the delivery ofmolecules into cells and tissues, including the skin. Inthis study, in order to control the degree of transdermal and topical drug delivery, EP at different amplitudes ofelectric pulses was evaluated. A new in vivo real-time monitoring system based on fluorescently labeled moleculeswas developed, for the quantification of transdermal and topical drug delivery. EP of the mouse skin wasperformedwith new non-invasive multi-array electrodes, delivering different amplitudes of electric pulses rangingfrom 70 to 570 V, between the electrode pin pairs. Patches, soaked with 4 kDa fluorescein-isothiocyanatelabeled dextran (FD), doxorubicin (DOX) or fentanyl (FEN), were applied to the skin before and after EP. Thenew monitoring system was developed based on the delivery of FD to and through the skin. FD relative quantitywas determined with fluorescence microscopy imaging, in the treated region of the skin for topical delivery andin a segment of the mouse tail for transdermal delivery. The application of electric pulses for FD delivery resultedin enhanced transdermal delivery. Depending on the amplitude of electric pulses, it increased up to the amplitudeof 360 V, and decreased at higher amplitudes (460 and 570 V). Topical delivery steadily enhanced withincreasing the amplitude of the delivered electric pulses, being even higher than after tape stripping used as apositive control. The non-invasive monitoring of the delivery of DOX, a fluorescent chemotherapeutic drug, qualitativelyand quantitatively confirmed the effects of EP at 360 and 570 V pulse amplitudes on topical and transdermaldrug delivery. Delivery of FEN at 360 and 570 V pulse amplitudes verified the observed effects asobtained with FD and DOX, by the measured physiological responses of the mice as well as FEN plasma concentration.This study demonstrates that with the newly developed non-invasive multi-array electrodes andwith the varying electric pulse amplitude, the amount of topical and transdermal drug delivery to the skin canbe controlled. Furthermore, the newly developed monitoring systemprovides a tool for rapid real-time determinationof both, transdermal and topical delivery, when the delivered molecule is fluorescent.
COBISS.SI-ID: 1617019