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Actas Dermo-sifiliograficas 2022Burn scars cause high morbidity in the form of contractures, body disfigurement, and itching, and they also have a high emotional impact that adversely affects patient... (Review)
Review
Burn scars cause high morbidity in the form of contractures, body disfigurement, and itching, and they also have a high emotional impact that adversely affects patient quality of life. Laser therapy has proven effective in this setting. It is superior to topical treatments and can be used in conjunction with surgery, helping to reduce morbidity. The use of lasers in hospital dermatology departments, however, is still limited. Carbon dioxide laser resurfacing is the most widely used modality for reducing scar thickness, improving textural abnormalities, and treating contractures. Treatments improve mobility for patients with constrictions. Pulsed dye laser treatments are particularly useful for reducing erythema in recent burn scars and preventing subsequent hypertrophy. Pigment laser treatments with short pulse durations (nanoseconds or picoseconds) can improve hyperpigmentation. In this article, we review the evidence for the use of laser therapy for burn scars and propose a treatment algorithm.
Topics: Humans; Cicatrix; Cicatrix, Hypertrophic; Lasers, Gas; Burns; Quality of Life; Laser Therapy; Contracture; Treatment Outcome
PubMed: 35963335
DOI: 10.1016/j.ad.2022.06.018 -
Bioelectricity Dec 2019The purpose of this review article is to summarize our current understanding of the efficacy and safety of cardiac defibrillation with nanosecond shocks. Experiments in... (Review)
Review
The purpose of this review article is to summarize our current understanding of the efficacy and safety of cardiac defibrillation with nanosecond shocks. Experiments in isolated hearts, using optical mapping of the electrical activity, have demonstrated that nanosecond shocks can defibrillate with lower energies than conventional millisecond shocks. Single defibrillation strength nanosecond shocks do not cause obvious damage, but repeated stimulation leads to deterioration of the hearts. In isolated myocytes, nanosecond pulses can also stimulate at lower energies than at longer pulses and cause less electroporation (propidium uptake). The mechanism is likely electroporation of the plasma membrane. Repeated stimulation leads to distorted calcium gradients.
PubMed: 32685917
DOI: 10.1089/bioe.2019.0030 -
Bioelectrochemistry (Amsterdam,... Dec 2020Conventional electric stimuli of micro- and millisecond duration excite or activate cells at voltages 10-100 times below the electroporation threshold. This ratio is... (Review)
Review
Conventional electric stimuli of micro- and millisecond duration excite or activate cells at voltages 10-100 times below the electroporation threshold. This ratio is remarkably different for nanosecond electric pulses (nsEP), which caused excitation and activation only at or above the electroporation threshold in diverse cell lines, primary cardiomyocytes, neurons, and chromaffin cells. Depolarization to the excitation threshold often results from (or is assisted by) the loss of the resting membrane potential due to ion leaks across the membrane permeabilized by nsEP. Slow membrane resealing and the build-up of electroporation damages prevent repetitive excitation by nsEP. However, peripheral nerves and muscles are exempt from this rule and withstand multiple cycles of excitation by nsEP without the loss of function or signs of electroporation. We show that the damage-free excitation by nsEP may be enabled by the membrane charging time constant sufficiently large to (1) cap the peak transmembrane voltage during nsEP below the electroporation threshold, and (2) extend the post-nsEP depolarization long enough to activate voltage-gated ion channels. The low excitatory efficacy of nsEP compared to longer pulses makes them advantageous for medical applications where the neuromuscular excitation is an unwanted side effect, such as electroporation-based cancer and tissue ablation.
Topics: Animals; Cell Line; Cell Membrane Permeability; Electric Stimulation; Electroporation; Humans; Membrane Potentials
PubMed: 32711366
DOI: 10.1016/j.bioelechem.2020.107598 -
FEBS Letters Jan 2023Formulations of hydrogen tunneling in enzyme-catalysed C-H activation reactions indicate enthalpic barriers to reaction that are independent of chemical steps and... (Review)
Review
Formulations of hydrogen tunneling in enzyme-catalysed C-H activation reactions indicate enthalpic barriers to reaction that are independent of chemical steps and dependent on the protein scaffold. A tool to identify catalytically relevant site-specific protein thermal networks has emerged from temperature-dependent hydrogen deuterium exchange (TDHDX). Focusing on mutant enzyme forms with altered activation energies for catalysis, TDHDX provides a comparative analysis of the impact of mutation on E for local protein unfolding. Identified thermal networks appear unrelated to protein scaffold conservation and track to the dictates of the catalysed reaction, including sites for metal binding. The positions of thermal networks provide a framework for further understanding of time-dependent, functionally relevant protein motions. Measurement of nanosecond Stokes shifts at the surface of the thermal network in soybean lipoxygenase yields activation energies that are identical to E values measured for k . This finding identifies a rapid (> nanosecond), long-range and cooperative structural reorganization as the thermal barrier to catalysis. A model for protein dynamics is put forward that integrates broadly distributed protein conformational sampling with protein embedded thermal networks.
Topics: Models, Molecular; Proteins; Hydrogen; Thermodynamics; Temperature; Catalysis; Lipoxygenase; Kinetics
PubMed: 36239559
DOI: 10.1002/1873-3468.14515 -
Nature Communications Apr 2022Electrical switching based data center networks have an intrinsic bandwidth bottleneck and, require inefficient and power-consuming multi-tier switching layers to cope...
Electrical switching based data center networks have an intrinsic bandwidth bottleneck and, require inefficient and power-consuming multi-tier switching layers to cope with the rapid growing traffic in data centers. With the benefits of ultra-large bandwidth, high-efficient cost and power consumption, switching traffic in the optical domain has been investigated to replace the electrical switches inside data center networks. However, the deployment of nanosecond optical switches remains a challenge due to the lack of corresponding nanosecond switch control, the lack of optical buffers for packet contention, and the requirement of nanosecond clock and data recovery. In this work, a nanosecond optical switching and control system has been experimentally demonstrated to enable an optically switched data center network with 43.4 nanosecond switching and control capability and with packet contention resolution as well as 3.1 nanosecond clock and data recovery.
PubMed: 35474216
DOI: 10.1038/s41467-022-29913-1 -
International Journal of Molecular... May 2022Nanosecond Pulsed Electric Field (nsPEF) is an electrostimulation technique first developed in 1995; nsPEF requires the delivery of a series of pulses of high electric... (Review)
Review
Nanosecond Pulsed Electric Field (nsPEF) is an electrostimulation technique first developed in 1995; nsPEF requires the delivery of a series of pulses of high electric fields in the order of nanoseconds into biological tissues or cells. They primary effects in cells is the formation of membrane nanopores and the activation of ionic channels, leading to an incremental increase in cytoplasmic Ca2+ concentration, which triggers a signaling cascade producing a variety of effects: from apoptosis up to cell differentiation and proliferation. Further, nsPEF may affect organelles, making nsPEF a unique tool to manipulate and study cells. This technique is exploited in a broad spectrum of applications, such as: sterilization in the food industry, seed germination, anti-parasitic effects, wound healing, increased immune response, activation of neurons and myocites, cell proliferation, cellular phenotype manipulation, modulation of gene expression, and as a novel cancer treatment. This review thoroughly explores both nsPEF's history and applications, with emphasis on the cellular effects from a biophysics perspective, highlighting the role of ionic channels as a mechanistic driver of the increase in cytoplasmic Ca2+ concentration.
Topics: Apoptosis; Calcium; Cell Proliferation; Electricity; Ion Channels
PubMed: 35682837
DOI: 10.3390/ijms23116158 -
Bioelectrochemistry (Amsterdam,... Aug 2021Nanosecond electric pulses have several potential advantages in electroporation-based procedures over the conventional micro- and millisecond pulses including low level...
Nanosecond electric pulses have several potential advantages in electroporation-based procedures over the conventional micro- and millisecond pulses including low level of heating, reduced electrochemical reactions and reduced muscle contractions making them alluring for use in biomedicine and food industry. The aim of this study was to evaluate if nanosecond pulses can enhance the cytotoxicity of chemotherapeutics bleomycin and cisplatin in vitro and to quantify metal release from electrodes in comparison to 100 μs pulses commonly used in electrochemotherapy. The effects of nanosecond pulse parameters (voltage, pulse duration, number of pulses) on cell membrane permeabilization, resealing and on cell survival after electroporation only and after electrochemotherapy with bleomycin and cisplatin were evaluated on Chinese hamster ovary cells. Application of permeabilizing nanosecond pulses in combination with chemotherapeutics resulted in successful cell kill. Higher extracellular concentrations of bleomycin - but not cisplatin - were needed to achieve the same decrease in cell survival with nanosecond pulses as with eight 100 μs pulses, however, the tested bleomycin concentrations were still considerably lower compared to doses used in clinical practice. Decreasing the pulse duration from microseconds to nanoseconds and concomitantly increasing the amplitude to achieve the same biological effect resulted in reduced release of aluminum ions from electroporation cuvettes.
Topics: Aluminum; Animals; Antineoplastic Agents; Apoptosis; Bleomycin; CHO Cells; Cell Survival; Cisplatin; Cricetulus; Electrochemotherapy; Electrodes; Neoplasms
PubMed: 33743336
DOI: 10.1016/j.bioelechem.2021.107798 -
Bioelectricity Dec 2019Nano-Pulse Stimulation (NPS) therapy applies nanosecond pulsed electric fields to cells and tissues. It is a nonthermal modality that uses ultrashort pulses of... (Review)
Review
Nano-Pulse Stimulation (NPS) therapy applies nanosecond pulsed electric fields to cells and tissues. It is a nonthermal modality that uses ultrashort pulses of electrical energy in the nanosecond domain. The cellular response to this therapy can be quite varied depending on the number of pulses applied and the total energy delivered. Reviewed in this study are some clinical trial data describing the effects of NPS therapy on normal skin as well as three different skin lesions as part of the first commercial application of this technology. NPS therapy has been found to clear seborrheic keratosis lesions with an 82% efficacy and sebaceous gland hyperplasia with a 99.5% efficacy. Pilot studies on warts indicated that 60% of the NPS-treated warts were completely cleared within 60 days. NPS therapy can be used to treat cellular lesions in the epidermis and dermis without affecting noncellular components such as collagen and fibrin.
PubMed: 34471826
DOI: 10.1089/bioe.2019.0027 -
World Journal of Gastroenterology Jun 2020The number of liver cancer patients is likely to continue to increase in the coming decades due to the aging of the population and changing risk factors. Traditional... (Review)
Review
The number of liver cancer patients is likely to continue to increase in the coming decades due to the aging of the population and changing risk factors. Traditional treatments cannot meet the needs of all patients. New treatment methods evolved from pulsed electric field ablation are expected to lead to breakthroughs in the treatment of liver cancer. This paper reviews the safety and efficacy of irreversible electroporation in clinical studies, the methods to detect and evaluate its ablation effect, the improvements in equipment and its antitumor effect, and animal and clinical trials on electrochemotherapy. We also summarize studies on the most novel nanosecond pulsed electric field ablation techniques and . These research results are certain to promote the progress of pulsed electric field in the treatment of liver cancer.
Topics: Animals; Electrochemotherapy; Electroporation; Humans; Liver Neoplasms
PubMed: 32655266
DOI: 10.3748/wjg.v26.i24.3421