Biphasic Regulation of Apoptosis Following Gastric Irreversible Electroporation Using Tissue Immunohistochemistry of Activated Caspase-3 with TUNEL Method.

The regulation of apoptosis is the primary goal of ablation therapy. Irreversible electroporation (IRE) is a promising non-thermal tissue ablation-based therapy that induces apoptosis by manipulating electrical conditions. This study aimed to investigate IRE-induced gastric tissue apoptosis in response to changes in the electric field intensity, followed by the repair process. Among the 52 rats used in this study, 24 were used to explore apoptosis, and 28 were used to study regeneration. The apoptosis-to-necrosis ratio of the electrical field strength was evaluated using terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling and caspase-3 immunohistochemistry. The size of IRE-induced ulcers in the gastric tissue continuously increased with increasing electrical intensity (r2 = 0.830, p < 0.001). The level of apoptosis gradually decreased after peaking at 200 V (1000 V/cm). The size of the 400 V-ablated ulcers continued to decrease, and they were not visible by day 14. The proliferation and migration of epithelial cells with fibroblasts were observed on day 3 and augmented on day 7 post-ablation. This investigation demonstrated the biphasic activation of apoptosis with respect to the electrical field strength. Visually and histologically, IRE-induced gastric ulcers demonstrated complete tissue regeneration after two weeks.

The Process of Sterilizing Tattoo Inks Releases Formaldehyde.

INTRODUCTION: Around 12% of Europeans and 20% of Americans have at least one tattoo. Tattoo inks, the substances used to create tattoos on the body, consist of chemicals that contain formaldehyde, which can be harmful to human health. The amount of formaldehyde present in commercially available tattoo inks and its causes are not well understood. METHODS: We investigated the levels of formaldehyde in tattoo ink products sold in different countries and identified the factors contributing to its production. We also explored methods to reduce formaldehyde generation in tattoo inks. Seven tattoo inks from various brands were tested. RESULTS: Formaldehyde release was predominantly associated with gamma radiation sterilization. Formaldehyde levels were observed to be higher in compositions containing organic components compared to those with inorganic components, irrespective of sterilization method and container type. Glycerin released over seven times more formaldehyde than other components during gamma-ray sterilization. CONCLUSION: The results suggest that the presence of hydroxyl groups in carbon organic compounds in tattoo ink leads to photodegradation during gamma-ray radiation sterilization, resulting in increased concentrations of formaldehyde. Further research is needed to examine the chemical reactions occurring during sterilization processes and identify alternative sterilization methods that minimize formaldehyde formation. Additionally, the development of tattoo inks with reduced formaldehyde content and the establishment of strict quality control measures can help ensure the safety of tattooing practices.

Assessment of efficacy and safety of advanced endoscopic irreversible electroporation catheter in the esophagus.

Nonthermal irreversible electroporation (NTIRE) is emerging as a promising tissue ablation technique. However, maintaining irreversible electroporation (IRE) electrodes against displacement during strong esophageal spasms remains an obstacle. The present study aimed to evaluate the efficacy and safety of newly designed balloon-type endoscopic IRE catheters. Six pigs were randomly allocated to each catheter group, and each pig was subjected to four ablations at alternating voltages of 1500 V and 2000 V. Esophagogastroscopy was performed during the IRE. The ability of balloon-type catheters to execute complete IRE with 40 pulses was assessed. The success rate was higher for the balloon-type catheter than that for the basket-type (12/12 [100%] vs. 2/12 [16.7%], p < 0.001). Following gross inspection and histologic analysis of the 1500-V vs. 2000-V balloon-type catheter revealed a larger mucosal damage area (105.3 mm2 vs. 140.8 mm2, p = 0.004) and greater damage depth (476 µm vs. 900 µm, p = 0.02). Histopathology of the ablated tissue revealed separated epithelium, inflamed lamina propria, congested muscularis mucosa, necrotized submucosa, and disorganized muscularis propria. Balloon-type catheters demonstrated efficacy, achieving full electrical pulse sequences under NTIRE conditions, and a safe histological profile below 2000 V (1274 V/cm). Optimal electrical conditions and electrode arrays pose ongoing challenges.

Histological Response to 5†kHz Irreversible Electroporation in a Porcine Liver Model.

Unlike necrosis by thermal ablation, irreversible electroporation (IRE) is known to induce apoptosis by disrupting plasma membrane integrity with electric pulses while preserving the structure of blood vessels and bile ducts in liver tissue without a heat sink effect. This study aimed to investigate thermal damage and histopathological effects in the porcine liver by high-frequency electric pulses (5 kHz) which is much higher than the widely used 1 Hz. The electric field and thermal distributions of 5 kHz electric pulses were compared with those of 1 Hz in numerical simulations. 5 kHz-IRE was applied on pigs under ultrasound imaging to guide the electrode placement. The animals underwent computed tomography (CT) examination immediately and 1 day after IRE. After CT, IRE-treated tissues were taken and analyzed histologically. CT revealed that hepatic veins were intact for 1-day post-IRE. Histopathologically, the structure of the portal vein was intact, but endothelial cells were partially removed. In addition, the hepatic artery structure from which endothelial cells were removed were not damaged, while the bile duct structure and cholangiocytes were intact. The thermal injury was observed only in the vicinity of the electrodes as simulated in silico. 5 kHz-IRE generated high heat due to its short pulse interval, but the thermal damage was limited to the tissue around the electrodes. The histopathological damage caused by 5 kHz-IRE was close to that caused by 1 Hz-IRE. If a short-time treatment is required for reasons such as anesthesia, high-frequency IRE treatment is worth considering. Our observations will contribute to a better understanding of the IRE phenomena and search for advanced therapeutic conditions.

Impact of sarcopenia and phase angle on mortality of the very elderly.

BACKGROUND: Sarcopenia is a major component of geriatric syndrome and associated with poor clinical outcomes and mortality. However, diagnosing sarcopenia in the very elderly is difficult, and data on its epidemiology and devastating effects in this group are scarce. Phase angle (PA) is measured using bioimpedance spectroscopy and known to reflect cellular integrity and health. This study aimed to clarify the impact of sarcopenia and PA on mortality risk in very elderly people living in long-term care facilities. METHODS: This prospective cohort study enrolled elderly residents living in nine long-term care facilities. We collected the participants' data, such as body mass index (BMI), comorbidities and laboratory data, from September to October 2017 and mortality data until October 2019. Nutritional status was evaluated using the Mini Nutritional Assessment (MNA) score, and multifrequency bioimpedance spectroscopy was used to assess body composition including PA. Appendicular skeletal muscle mass was calculated using the body composition monitor-derived equation of Taiwan's researchers. Sarcopenia was diagnosed using the European Working Group on Sarcopenia in Older People 2 (EWGSOP2) definition (sarcopenia vs. normal group). We divided the participants into two groups according to the median PA value of 3.65° (high vs. low group) and performed multivariate regression analyses to verify the association with mortality risk according to sarcopenia diagnosis or PA group. RESULTS: A total of 279 elderly participants were enrolled; of them, 238 (85.3%) were diagnosed with sarcopenia according to EWGSOP2 guidelines. The median patient age was 83 years, 211 (75.6%) were female and the median BMI was 20.4 kg/m2 . The sarcopenia group was older than the normal group (84 vs. 81 years; P = 0.002), had a lower mean BMI (19.8 vs. 26.6 kg/m2 , P < 0.001) and had a lower MNA score (9 vs. 12 points, P < 0.001). Sarcopenia was associated with a higher mortality risk after the adjustment for age, sex and diabetes mellitus (hazard ratio [HR], 3.744; 95% confidence interval [CI], 1.155-12.134; P = 0.028). A low PA was associated with sarcopenia, older age, female sex, low MNA score and overhydration volume; it was also a significant predictor of mortality after the adjustment for age, sex, diabetes mellitus and MNA score (HR, 0.593; 95% CI, 0.420-0.837; P = 0.003). CONCLUSIONS: Sarcopenia is prevalent among the very elderly patients in long-term care facilities. Sarcopenia and low PA are significantly associated with higher mortality risk.

Effects of different applied voltages of irreversible electroporation on prostate cancer in a mouse model.

As a non-thermal ablation method, irreversible electroporation (IRE) has been widely investigated in the treatment of prostate cancer. However, no consensus has been achieved on the optimal parameters of IRE for prostate cancer. Since high voltage is known to carry risks of muscle contraction and patient discomfort, it is crucial to identify the minimum but effective and safer applied voltage to inhibit tumor growth. In this study, the effect of different applied voltages of IRE on prostate cancer was evaluated in BALB/c nude mice. Mathematical simulation and measurement of the actual ablation area revealed a larger ablation area at a higher voltage. In in vivo experiment, except for the three different voltages applied, all groups received identical electrical conditions: pulse number, 180 (20 groups × 9 pulses/group); pulse width, 100 µs; pulse interval, 2 ms; distance between the electrodes, 5 mm; and electrode exposure length, 15 mm. Whilst the tumor volume initially decreased in the 500 V (1000 V/cm) and 700 V (1400 V/cm) groups and subsequently increased, only a transient increase followed by a continuous decrease until the sacrifice was observed in the 900 V (1800 V/cm) group. This result demonstrated a lasting effect of a higher applied voltage on tumor growth inhibition. The histological, immunohistochemical, and western blot findings all confirmed IRE-induced apoptosis in the treatment groups. Taken together, 900 V seemed to be the minimum applied voltage required to reduce tumor growth, though subsequent studies are anticipated to further narrow the voltage intervals and lower the minimum voltage required for tumor inhibition.

Novel platinum bipolar electrode for irreversible electroporation in prostate cancer: preclinical study in the beagle prostate.

The exposure of the prostate to high electric field strength during irreversible electroporation (IRE) has been extensively investigated. Multiple monopolar electrodes, however, have risks of organ piercing and bleeding when placing electrodes. A novel bipolar electrode made of pure platinum and stainless steel was developed for prostate cancer ablation. Voltages of 500 and 700 V were applied to the beagle prostate with this electrode to evaluate ablated tissues and their characteristics. IRE procedures were technically successful in all dogs without procedure-related complications. The current that flowed through the anode and cathode while applying 500 and 700 V were 1.75 ± 0.25 A and 2.22 ± 0.35 A, respectively. TUNEL assays showed that the estimated ablated areas when applying 500 and 700 V were 0.78 cm2 and 1.21 cm2, respectively. The minimum electric field strength threshold required for induction of IRE was 800 V/cm. The platinum electrode was resistant to corrosion. The IRE procedure for beagle prostates using a single bipolar electrode was technically feasible and safe. The novel bipolar electrode has great potential for treating human prostate cancer with fewer IRE-related complications.

Photobiomodulation as an antioxidant substitute in post-thawing trauma of human stem cells from the apical papilla.

Cryopreservation, the most common method of preserving stem cells, requires post-processing because it produces trauma to the cells. Post-thawing trauma typically induces cell death, elevates reactive oxygen species (ROS) concentration, and lowers mitochondrial membrane potential (MMP). Although this trauma has been solved using antioxidants, we attempted to use photobiomodulation (PBM) instead of chemical treatment. We used a 950-nm near-infrared LED to create a PBM device and chose a pulsed-wave mode of 30 Hz and a 30% duty cycle. Near-infrared radiation (NIR) at 950 nm was effective in reducing cell death caused by hydrogen peroxide induced-oxidative stress. Cryodamage also leads to apoptosis of cells, which can be avoided by irradiation at 950 nm NIR. Irradiation as post-processing for cryopreservation had an antioxidant effect that reduced both cellular and mitochondrial ROS. It also increased mitochondrial mass and activated mitochondrial activity, resulting in increased MMP, ATP generation, and increased cytochrome c oxidase activity. In addition, NIR increased alkaline phosphatase (ALP) activity, a biomarker of differentiation. As a result, we identified that 950 nm NIR PBM solves cryodamage in human stem cells from the apical papilla, indicating its potential as an alternative to antioxidants for treatment of post-thawing trauma, and further estimated its mechanism.

Feasibility and effectiveness of endoscopic irreversible electroporation for the upper gastrointestinal tract: an experimental animal study.

Irreversible electroporation (IRE) is a local non-thermal ablative technique currently used to treat solid tumors. Here, we investigated the clinical potency and safety of IRE with an endoscope in the upper gastrointestinal tract. Pigs were electroporated with recently designed endoscopic IRE catheters in the esophagus, stomach, and duodenum. Two successive strategies were introduced to optimize the electrical energy for the digestive tract. First, each organ was electroporated and the energy upscaled to confirm the upper limit energy inducing improper tissue results, including bleeding and perforation. Excluding the unacceptable energy from the first step, consecutive electroporations were performed with stepwise reductions in energy to identify the energy that damaged each layer. Inceptive research into inappropriate electrical intensity contributed to extensive hemorrhage and bowel perforation for each tissue above a certain energy threshold. However, experiments performed below the precluded energy accompanying hematoxylin and eosin staining and terminal deoxynucleotidyl transferase dUTP nick-end labeling assays showed that damaged mucosal area and depth significantly decreased with decreased energy. Relevant histopathology showed infiltration of inflammatory cells with pyknotic nuclei at the electroporated lesion. This investigation demonstrated the possibility of endoscopic IRE in mucosal dysplasia or early malignant tumors of the hollow viscus.

Association between sunlight exposure and risk of prostate cancer: a systematic review and meta-analysis.

BACKGROUND: The prevalence of prostate cancer (PC) is increasing worldwide. An association between sunlight exposure and PC risk has been described by a previously published meta-analysis, although the level of statistical significance was not reached. We have, therefore, performed an updated systematic review and meta-analysis to further elucidate this potential connection. METHODS: To identify relevant articles, we conducted an in-depth search of 4 electronic databases (PubMed, Embase, the Web of Science and Scopus) for manuscripts published prior to March 2021. A random-effects model was used to compute a meta-estimate of the effects of sunlight exposure on risk of PC. RESULTS: Of the 5680 articles that were initially identified in our search, 12 observational epidemiological studies encompassing 29 282 cases of PC were selected for inclusion in the qualitative systematic review. Of these, two case-control studies were excluded from the meta-analysis. Comparing highest-to-lowest exposure, personal sunlight exposure was significantly associated with a decreased risk of PC [odds ratio (OR) = 0.67, 95% CI: 0.57-0.78] in a random-effects meta-analysis; however, high heterogeneity was present (I2 = 85.9%). Comparing moderate-to-lowest exposure, there was a non-significant relationship between personal sunlight exposure and the risk of PC (OR = 0.87, 95% CI: 0.68-1.10; I2 = 74.0%). CONCLUSIONS: Our findings indicate that exposure to sunlight may protect against PC. The limitations of our research are occurrence of publication bias and a substantial heterogeneity due to a diversity of criteria for measuring sunlight exposure.

Sunlight exposure in association with risk of lymphoid malignancy: a meta-analysis of observational studies.

PURPOSE: Several observational studies have shown contradictory results regarding the association between sunlight exposure and the risk of malignant lymphoma. Thus, we aimed to systematically determine the association between sunlight exposure and lymphoid malignancy risk through a meta-analysis. METHODS: A thorough search of four electronic databases (PubMed, Embase, Web of Science, and Scopus) was performed to identify eligible studies until 13 August 2020. A random-effects model was used to calculate risk estimates of sunlight exposure. The main outcome measure was the risk of lymphoid malignancy subtypes with odds ratios (ORs) and 95% confidence intervals (CIs) according to various forms of solar ultraviolet radiation. RESULTS: In total, 17 case-control studies and 9 cohort studies including 216,285 non-Hodgkin lymphoma (NHL) and 23,017 Hodgkin's lymphoma (HL) patients were included in the final analysis. Personal sunlight exposure was significantly associated with a decreased risk of HL (OR 0.77; 95% CI 0.68-0.87) and NHL (OR 0.81; 95% CI 0.71-0.92), including all subtypes except T-cell lymphoma. Ambient sunlight exposure at residence was associated with a reduced risk of HL (OR 0.88; 95% CI 0.81-0.95) and all NHL subtypes (OR 0.84; 95% CI 0.73-0.96), except for chronic lymphocytic leukemia/small lymphocytic lymphoma. As the number of sunburns and sunbaths increased, the risk of NHL tended to decrease. CONCLUSION: While there was an observed protective effect both from case-control and prospective studies, substantial heterogeneity was found in the current study. Thus, more evidence is required to confirm that promoting sunlight exposure can prevent the development of lymphoid neoplasia.

Novel Ablation Therapy Using Endoscopic Irreversible Electroporation in the Bile Duct: A Pilot Animal Study.

BACKGROUND/AIMS: Irreversible electroporation (IRE) is a relatively new ablation method. However, the application of IRE ablation in the treatment of biliary disease has not been attempted. A minimally invasive approach using endoscopic retrograde cholangiopancreatography (ERCP) can be a novel therapeutic modality for IRE ablation. In this study, we aimed to investigate the feasibility of endoscopic IRE for the biliary tract using an animal model. METHODS: A new catheter-type electrode was developed for endoscopic IRE ablation of the biliary tract. We performed ERCP and endoscopic IRE ablations in the normal common bile duct of Yorkshire pigs. The experimental setting of IRE was 500 V/cm (50 pulses, 100-µs length). The animals were sacrificed after 24 hr, and the ablated bile duct was examined. RESULTS: Well-demarcated focal color changes were observed on the mucosa of the common bile duct. The depth of change after IRE was confined to the mucosal and submucosal layers. Apoptotic changes in the bile duct were observed only around the IRE ablation area. Immunohistochemistry assay showed cell death in the bile duct along the electrode. CONCLUSION: Endoscopic IRE ablation using ERCP was successfully performed in the common bile duct. It can be a potential option for the treatment of biliary tumors.

Aligned Nanofiber-Guided Bone Regeneration Barrier Incorporated with Equine Bone-Derived Hydroxyapatite for Alveolar Bone Regeneration.

Post-surgery failure of dental implants due to alveolar bone loss is currently critical, disturbing the quality of life of senior dental patients. To overcome this problem, bioceramic or bone graft material is loaded into the defect. However, connective tissue invasion instead of osteogenic tissue limits bone tissue regeneration. The guided bone regeneration concept was adapted to solve this problem and still has room for improvements, such as biochemical similarity or oriented structure. In this article, an aligned electrospun-guided bone regeneration barrier with xenograft equine bone-derived nano hydroxyapatite (EBNH-RB) was fabricated by electrospinning EBNH/PCL solution on high-speed rotating drum collector and fiber characterization, viability and differentiation enhancing properties of mesenchymal dental pulp stem cell on the barrier was determined. EBNH-RB showed biochemical and structural similarity to natural bone tissue electron microscopy image analysis and x-ray diffractometer analysis, and had a significantly better effect in promoting osteogenesis based on the increased bioceramic content by promoting cell viability, calcium deposition and osteogenic marker expression, suggesting that they can be successfully applied to regenerate alveolar bone as a guided bone regeneration barrier.

Incorporation of Reversible Electroporation Into Electrolysis Accelerates Apoptosis for Rat Liver Tissue.

Tissue electrolysis is an alternative modality that uses a low intensity direct electric current passing through at least 2 electrodes within the tissue and resulting electrochemical products including chlorine and hydrogen. These products induce changes in pH around electrodes and cause dehydration resulting from electroosmotic pressure, leading to changes in microenvironment and thus metabolism of the tissues, yielding apoptosis. The procedure requires adequate time for electrochemical reactions to yield products sufficient to induce apoptosis of the tissues. Incorporation of electroporation into electrolysis can decrease the treatment time and enhance the efficiency of electrolytic ablation. Electroporation causes permeabilization in the cell membrane allowing the efflux of potassium ions and extension of the electrochemical area, facilitating the electrolysis process. However, little is known about the combined effects on apoptosis in liver ablation. In this study, we performed an immunohistochemical evaluation of apoptosis for the incorporation of electroporation into electrolysis in liver tissues. To do so, the study was performed with microelectrodes for fixed treatment time while the applied voltage varied to increase the applied total energy for electrolysis. The apoptotic rate for electrolytic ablation increased with enhanced applied energy. The apoptotic rate was 4.31 ± 1.73 times that of control in the synergistic combination compared to 1.49 ± 0.33 times that of the control in electrolytic ablation alone. Additionally, tissue structure was better preserved in synergistic combination ablation compared to electrolysis with an increment of 3.8 mA. Thus, synergistic ablation may accelerate apoptosis and be a promising modality for the treatment of liver tumors.

Classification of cervical neoplasms on colposcopic photography using deep learning.

Colposcopy is widely used to detect cervical cancers, but experienced physicians who are needed for an accurate diagnosis are lacking in developing countries. Artificial intelligence (AI) has been recently used in computer-aided diagnosis showing remarkable promise. In this study, we developed and validated deep learning models to automatically classify cervical neoplasms on colposcopic photographs. Pre-trained convolutional neural networks were fine-tuned for two grading systems: the cervical intraepithelial neoplasia (CIN) system and the lower anogenital squamous terminology (LAST) system. The multi-class classification accuracies of the networks for the CIN system in the test dataset were 48.6 ± 1.3% by Inception-Resnet-v2 and 51.7 ± 5.2% by Resnet-152. The accuracies for the LAST system were 71.8 ± 1.8% and 74.7 ± 1.8%, respectively. The area under the curve (AUC) for discriminating high-risk lesions from low-risk lesions by Resnet-152 was 0.781 ± 0.020 for the CIN system and 0.708 ± 0.024 for the LAST system. The lesions requiring biopsy were also detected efficiently (AUC, 0.947 ± 0.030 by Resnet-152), and presented meaningfully on attention maps. These results may indicate the potential of the application of AI for automated reading of colposcopic photographs.

Association between anaemia and adult depression: a systematic review and meta-analysis of observational studies.

BACKGROUND: Several observational studies have been conducted to investigate the link between anaemia and adult depression but have shown inconsistent results. This systematic review and meta-analysis was performed to investigate this association. METHODS: A comprehensive search of four electronic databases (PubMed, EMBASE, PsycINFO and the Cochrane Library) was conducted to identify relevant papers published up to November 2019 for the systematic review and meta-analysis. The Newcastle-Ottawa Scale was used to assess the methodological quality of selected studies. A random-effects model was used to draw metaestimates of the relationship between anaemia and adult depression. RESULTS: A total of 9706 papers were retrieved, and 14 observational epidemiological studies (9 case-control studies and 5 prospective cohort studies) comprising 10 764 cases of depression were finally included in this meta-analysis. The mean age of the participants ranged from 38.4 to 75.0 years. A significant association was identified between low haemoglobin levels and adult depression (OR or relative risk 1.43; 95% CI 1.23 to 1.65). Subgroup analyses according to study design, mean age, diagnostic criteria of anaemia, geographical region, number of participants, methodological quality and adjustment for various confounding factors such as education, smoking, comorbid disorders, physical activity, alcohol intake and medication use showed similar results. CONCLUSIONS: The current study showed that anaemia was related to an increased risk of adult depression. One of the important limitations of our study was a moderate degree of heterogeneity due to the variety of assessment tools used to identify depression and the existence of publication bias. Another limitation of this meta-analysis was the lack of prospective cohort studies.

Association of resting heart rate with nonalcoholic fatty liver disease in postmenopausal women.

Resting heart rate, a simple and useful indicator of autonomic function, and its imbalance has emerged as an independent predictor of cardio metabolic diseases. Nonalcoholic fatty liver disease (NAFLD) is increasingly being diagnosed worldwide and is strongly associated with the features of cardiometabolic diseases. This study aimed to examine the association between resting heart rate and NAFLD in postmenopausal women.The cross-sectional study included 1017 postmenopausal women aged ≥46 years, who attended a health examination program. Resting heart rate and NAFLD were measured in all subjects who underwent a medical examination. Resting heart rate quartiles were categorized as follows: Q1: 56 to 65, Q2: 66 to 71, Q3: 72 to 78, and Q4: 79 to 99 beats/min. The odds ratios and 95% confidence intervals for NAFLD were calculated after adjusting for confounding variables across resting heart rate quartiles using multiple logistic regression analysis.The prevalence of NAFLD increased with increasing resting heart rate quartiles: 28.2% for Q1, 31.5% for Q2, 33.4% for Q3, and 38.1% for Q4 (P < .001). Compared to the 1st quartile, the odds ratio (95% confidence intervals) of NAFLD in the 4th quartile of resting heart rates was 2.11 (1.17-3.42) after adjusting for age, body mass index, cigarette smoking, regular exercise, blood pressure, total cholesterol, triglyceride, aspartate aminotransferase, and alanine aminotransferase levels.Resting heart rate was positively associated with NAFLD in postmenopausal women, suggesting that it could be a useful additional measure to assess the risk for NAFLD in postmenopausal women.

Effects of Actin Cytoskeleton Disruption on Electroporation In Vitro.

The role of actin fibers in cellular responses to external electric pulses is not clear yet. In this study, we utilized the blocker of actin polymerization, cytochalasin D (cytoD), and investigated its effects on the electropore generation. Eight 100 µs electric pulses of sub-kilovolt per centimeter voltage with 100 ms intervals were applied to adhered cells in vitro, and the membrane permeability was quantified using membrane-impermeable propidium iodide (PI) dye. With cytoD application, the transfer of PI dye decreased significantly in all the applied voltages. At the same time, the roughness of cells increased, the membrane stiffness decreased, and the transmembrane resting potential decreased. Our result supports that actin fibers have clear effects on electroporation through modulating membrane properties including transmembrane resting potential.

Physicochemical factors that affect electroporation of lung cancer and normal cell lines.

Electroporation is used for cancer therapy to efficiently destroy cancer tissues by transferring anticancer drugs into cancer cells or by irreversible tumor ablation without resealing pores. There is growing interest in the electroporation method for the treatment of lung cancer, which has the highest mortality rate among cancers. Improving the cancer cell selectivity has the potential to expand its use. However, the factors that influence the cell selectivity of electroporation are debatable. We aimed to identify the important factors that influence the efficiency of electroporation in lung cells. The electropermeabilization of lung cancer cells (H460, A549, and HCC1588) and normal lung cells (MRC5, WI26 and L132) was evaluated by the transfer of fluorescence dyes. We found that membrane permeabilization increased as cell size, membrane stiffness, resting transmembrane potential, and lipid cholesterol ratio increased. Among them, lipid composition was found to be the most relevant factor in the electroporation of lung cells. Our results provide insight into the differences between lung cancer cells and normal lung cells and provide a basis for enhancing the sensitivity of lung cancers cells to electroporation.

Characterization of irreversible electroporation on the stomach: A feasibility study in rats.

Irreversible electroporation (IRE) is a newly developed non-thermal ablative therapy. During the IRE procedure, the permeability of the cell membrane is irreversibly changed by application of high-energy pulses across the tissue. This induces the breakdown of cell homeostasis, and thereby cell death. Here, we present an in vivo study to demonstrate IRE ablation of gastric tissue and characterize the changes that occur with time therein. No significant complications were observed in the test rats during the experiment. The electroporated tissues exhibited apoptosis at 10, 24 and 48 h after IRE ablation. The apoptosis peaked at 10 h after IRE and then declined, suggesting that the ablated tissue rapidly recovered owing to intense metabolic activity. In addition, the electroporated tissues exhibited morphological changes such as pyknosis and karyorrhexis, while histological analysis showed that the blood vessels were preserved. Interestingly, electroporation greatly affected the mucosa and muscularis propria, but not the submucosa and serosa. This study suggests that IRE could potentially be used as a minimally invasive treatment for early gastric cancer that does not exhibit lymph node metastasis or dysplasia.