Two separate mechanisms are involved in membrane permeabilization during lipid oxidation.

Lipid oxidation is a universal degradative process of cell membrane lipids that is induced by oxidative stress and reactive oxygen and nitrogen species (RONS) in multiple pathophysiological situations. It has been shown that certain oxidized lipids alter membrane properties, leading to a loss of membrane function. Alteration of membrane properties is thought to depend on the initial membrane lipid composition, such as the number of acyl chain unsaturations. However, it is unclear how oxidative damage is related to biophysical properties of membranes. We therefore set out to quantify lipid oxidation through various analytical methods and determine key biophysical membrane parameters using model membranes containing lipids with different degrees of lipid unsaturation. As source for RONS, we used cold plasma, which is currently developed as treatment for infections and cancer. Our data revealed complex lipid oxidation that can lead to two main permeabilization mechanisms. The first one appears upon direct contact of membranes with RONS and depends on the formation of truncated oxidized phospholipids. These lipids seem to be partly released from the bilayer, implying that they are likely to interact with other membranes and potentially act as signaling molecules. This mechanism is independent of lipid unsaturation, does not rely on large variations in lipid packing, and is most probably mediated via short-living RONS. The second mechanism takes over after longer incubation periods and probably depends on the continued formation of lipid oxygen adducts such as lipid hydroperoxides or ketones. This mechanism depends on lipid unsaturation and involves large variations in lipid packing. This study indicates that polyunsaturated lipids, which are present in mammalian membranes rather than in bacteria, do not sensitize membranes to instant permeabilization by RONS but could promote long-term damage.

Mamoplastia redutora: da técnica ao impacto social / Reduction mammoplasty: from technique to social impact / Mamoplastia de reducción: de la técnica al impacto social

As mulheres com tamanhos excessivos das mamas sofrem de patologias definidas como gigantomastia, macromastia ou hipertrofia mamária, isso indica um processo em que os seios são patologicamente aumentados o que gera condições insalubres. Seu tamanho afeta diretamente sua saúde com danos psicológicos e na qualidade de vida. O tratamento inclui a retirada cirúrgica do tecido excedente no processo de melhora da qualidade de vida, visando reduzir os sintomas, melhorar a funcionalidade, o estado psicológico, além um melhoramento estético. Dessa forma, o presente estudo tem como objetivo realizar uma análise desde a técnica da mamoplastia redutora quanto aos seus impactos sociais. Trata-se de uma pesquisa qualitativa como foco a construção teórica e a discussão de questões atuais sobre o tema com base nas evidências das literaturas dos últimos cinco anos. As mulheres com gigantomastia experimentam melhorias na forma e funcionalidade da mama após a mamoplastia redutora. Há evidências substanciais de que esta cirurgia melhora significativamente a qualidade de vida do paciente, visto que há a redução do volume mamário que consequentemente melhora das dores lombares, as mamas ficam esteticamente mais adequadas para uso de roupas íntimas, além de cessar irritações cutâneas e infecções nas áreas das dobras. Muitas pacientes se beneficiam de uma melhor qualidade de vida ao não apresentarem mais esses sintomas listados. Realizar este procedimento tem sido considerado satisfatório pela maioria das pessoas, e com base na análise realizada, a maioria das pacientes priorizam os efeitos estéticos e funcional, além de reduzir o impacto em outras doenças mesmo essa patologia não sendo amplamente disponibilizada pelo SUS. De tal forma, essa direção de pesquisa busca contribuir para o desenvolvimento de pesquisas futuras e em andamento relacionadas a esse tema.

Women with excessive breast sizes suffer from pathologies defined as gigantomastia, macromastia, or breast hypertrophy, this indicates a process in which the breasts are pathologically enlarged which generates unhealthy conditions. Their size directly affects your health with psychological damage and quality of life. The treatment includes the surgical removal of the excess tissue in the process of improving quality of life, aiming to reduce symptoms, improve functionality, psychological state, and an aesthetic improvement. Thus, the present study aims to carry out an analysis from the technique of reduction mammoplasty as to its social impacts. This is a qualitative research focusing on theoretical construction and discussion of current issues on the subject based on evidence from the literatures of the last five years. Women with gigantomastia experience improvements in breast shape and functionality after reduction mammaplasty. There is substantial evidence that this surgery significantly improves the patient's quality of life, as there is a reduction in breast volume which consequently improves lower back pain, the breasts become more aesthetically pleasing for underwear, and skin irritation and infections in the fold areas cease. Many patients benefit from a better quality of life by no longer experiencing these listed symptoms. Performing this procedure has been considered satisfactory by most people, and based on the analysis performed, most patients prioritize the aesthetic and functional effects, besides reducing the impact on other diseases even though this pathology is not widely available by SUS. In such a way, this research direction seeks to contribute to the development of future and ongoing research related to this theme.

Las mujeres con excesivo tamaño mamario sufren patologías definidas como gigantomastia, macromastia o hipertrofia mamaria, esto indica un proceso en el que las mamas se agrandan patológicamente lo que genera condiciones insalubres. Su tamaño afecta directamente a la salud con daños psicológicos y a la calidad de vida. El tratamiento incluye la extirpación quirúrgica del exceso de tejido en el proceso de mejora de la calidad de vida, con el objetivo de reducir los síntomas, mejorar la funcionalidad, el estado psicológico, y una mejora estética. Así, el presente estudio pretende realizar un análisis a partir de la técnica de mamoplastia de reducción en cuanto a sus impactos sociales. Se trata de una investigación cualitativa centrada en la construcción teórica y la discusión de cuestiones actuales sobre el tema a partir de la evidencia de las literaturas de los últimos cinco años. Las mujeres con gigantomastia experimentan mejoras en la forma y funcionalidad de las mamas después de la mamoplastia de reducción. Existen pruebas sustanciales de que esta cirugía mejora significativamente la calidad de vida de la paciente, ya que se produce una reducción del volumen mamario que, en consecuencia, mejora el dolor lumbar, las mamas resultan más estéticas para la ropa interior y cesan la irritación de la piel y las infecciones en las zonas de los pliegues. Muchas pacientes se benefician de una mejor calidad de vida al dejar de experimentar estos síntomas enumerados. La realización de este procedimiento ha sido considerada satisfactoria por la mayoría de las personas, y con base en el análisis realizado, la mayoría de los pacientes priorizan los efectos estéticos y funcionales, además de reducir el impacto sobre otras enfermedades, aunque esta patología no esté ampliamente disponible por el SUS. De tal forma, esta dirección de investigación busca contribuir para el desarrollo de futuras y actuales investigaciones relacionadas a este tema.

Quantification of surface charging memory effect in ionization wave dynamics.

The dynamics of ionization waves (IWs) in atmospheric pressure discharges is fundamentally determined by the electric polarity (positive or negative) at which they are generated and by the presence of memory effects, i.e. leftover charges and reactive species that influence subsequent IWs. This work examines and compares positive and negative IWs in pulsed plasma jets (1 [Formula: see text]s on-time), showing the difference in their nature and the different resulting interaction with a dielectric BSO target. For the first time, it is shown that a surface charging memory effect is produced, i.e. that a significant amount of surface charges and electric field remain in the target in between discharge pulses (200 [Formula: see text]s off-time). This memory effect directly impacts IW dynamics and is especially important when using negative electric polarity. The results suggest that the remainder of surface charges is due to the lack of charged particles in the plasma near the target, which avoids a full neutralization of the target. This demonstration and the quantification of the memory effect are possible for the first time by using an unique approach, assessing the electric field inside a dielectric material through the combination of an advanced experimental technique called Mueller polarimetry and state-of-the-art numerical simulations.

Towards plasma jet controlled charging of a dielectric target at grounded, biased, and floating potential.

Electric field and surface charge measurements are presented to understand the dynamics in the plasma-surface interaction of a plasma jet and a dielectric surface. The ITO coated backside of the dielectric allowed to impose a DC bias and thus compare the influence of a grounded, biased and floating potential. When imposing a controlled potential at the back of the target, the periodical charging is directly dependent on the pulse length, irrespective of that control potential. This is because the plasma plume is sustained throughout the pulse. When uncontrolled and thus with a floating potential surface, charge accumulation and potential build-up prevents a sustained plasma plume. An imposed DC bias also leads to a continuous surface charge to be present accumulated on the plasma side to counteract the bias. This can lead to much higher electric fields (55 kV/cm) and surface charge (200 nC/cm[Formula: see text]) than observed previously. When the plasma jet is turned off, the continuous surface charge decreased to half its value in 25 ms. These results have implications for surface treatment applications.

Antibacterial and safety tests of a flexible cold atmospheric plasma device for the stimulation of wound healing.

Cold atmospheric plasma (CAP) devices generate an ionized gas with highly reactive species and electric fields at ambient air pressure and temperature. A flexible dielectric barrier discharge (DBD) was developed as an alternative antimicrobial treatment for chronic wounds. Treatment of Staphylococcus aureus in collagen-elastin matrices with CAP for 2 min resulted in a 4 log reduction. CAP treatment was less effective on S. aureus on dermal samples. CAP did not affect cellular activity or DNA integrity of human dermal samples when used for up to 2 min. Repeated daily CAP treatments for 2 min lowered cellular activity of dermal samples to 80% after 2 to 4 days, but this was not significant. Repeated treatment of ex vivo human burn wound models with CAP for 2 min did not affect re-epithelialization. Intact skin of 25 healthy volunteers was treated with CAP for 3× 20" to determine safety. Although participants reported moderate pain scores (numerical rating scale 3.3), all volunteers considered the procedure to be acceptable. Severe adverse events did not occur. CAP treatment resulted in a temporarily increased local skin temperature (≈3.4°C) and increased erythema. Lowering the plasma power resulted in a significantly lower erythema increase. Good log reduction (2.9) of bacterial load was reached in 14/15 volunteers artificially contaminated with Pseudomonas aeruginosa. This study demonstrated the in vitro and in vivo safety and efficacy in bacterial reduction of a flexible cold plasma device. Trial registration number NCT03007264, January 2, 2017 KEY POINTS: • CAP strongly reduced bacterial numbers both in vitro and in vivo. • Re-epithelialization of burn wound models was not affected by repeated CAP. • CAP treatment of intact skin was well tolerated in volunteers.

Safety and bactericidal efficacy of cold atmospheric plasma generated by a flexible surface Dielectric Barrier Discharge device against Pseudomonas aeruginosa in vitro and in vivo.

BACKGROUND: Cold atmospheric plasma (CAP), which is ionized gas produced at atmospheric pressure, could be a novel and potent antimicrobial therapy for the treatment of infected wounds. Previously we have shown that CAP generated with a flexible surface Dielectric Barrier Discharge (sDBD) is highly effective against bacteria in vitro and in ex vivo burn wound models. In the current paper, we determined the in vitro and in vivo safety and efficacy of CAP generated by this sDBD device. METHODS: The effect of CAP on DNA mutations of V79 fibroblasts was measured using a hypoxanthine-guanine-phosphoribosyltransferase (HPRT) assay. Furthermore, effects on cell proliferation, apoptosis and DNA damage in ex vivo burn wound models (BWMs) were assessed using immunohistochemistry. Next, 105 colony forming units (CFU) P. aeruginosa strain PAO1 were exposed to CAP in a 3D collagen-elastin matrix environment to determine the number of surviving bacteria in vitro. Finally, rat excision wounds were inoculated with 107 CFU PAO1 for 24 h. The wounds received a single CAP treatment, repeated treatments on 4 consecutive days with CAP, 100 µL of 1% (wt/wt) silver sulfadiazine or no treatment. Wound swabs and punch biopsies were taken to determine the number of surviving bacteria. RESULTS: Exposure of V79 fibroblasts to CAP did not increase the numbers of mutated colonies. Additionally, the number of proliferative, apoptotic and DNA damaged cells in the BWMs was comparable to that of the unexposed control. Exposure of PAO1 to CAP for 2 min resulted in the complete elimination of bacteria in vitro. Contrarily, CAP treatment for 6 min of rat wounds colonized with PAO1 did not effectively reduce the in vivo bacterial count. CONCLUSIONS: CAP treatment was safe but showed limited efficacy against PAO1 in our rat wound infection model.

In-situ monitoring of an organic sample with electric field determination during cold plasma jet exposure.

Pockels-based Mueller polarimetry is presented as a novel diagnostic technique for studying time and space-resolved and in-situ the interaction between an organic sample (a layer of onion cells) and non-thermal atmospheric pressure plasma. The effect of plasma is complex, as it delivers electric field, radicals, (UV) radiation, non-uniform in time nor in space. This work shows for the first time that the plasma-surface interaction can be characterized through the induced electric field in an electro-optic crystal (birefringence caused by the Pockels effect) while at the same moment the surface evolution of the targeted sample is monitored (depolarization) which is attached to the crystal. As Mueller polarimetry allows for separate detection of depolarization and birefringence, it is possible to decouple the entangled effects of the plasma. In the sample three spatial regions are identified where the surface evolution of the sample differs. This directly relates to the spatial in-homogeneity of the plasma at the surface characterized through the detected electric field. The method can be applied in the future to investigate plasma-surface interactions for various targets ranging from bio-films, to catalytic surfaces and plastics/polymers.

Revealing Plasma-Surface Interaction at Atmospheric Pressure: Imaging of Electric Field and Temperature inside the Targeted Material.

The plasma-surface interaction is studied for a low temperature helium plasma jet generated at atmospheric pressure using Mueller polarimetry on an electro-optic target. The influence of the AC kHz operating frequency is examined by simultaneously obtaining images of the induced electric field and temperature of the target. The technique offers high sensitivity in the determination of the temperature variation on the level of single degrees. Simultaneously, the evolution of the electric field in the target caused by plasma-driven charge accumulation can be measured with the threshold of the order of 105 V/m. Even though a specific electro-optic crystal is used to obtain the results, they are generally applicable to dielectric targets under exposure of a plasma jet when they are of 0.5 mm thickness, have a dielectric constant greater than 4 and are at floating potential. Other techniques to examine the induced electric field in a target do not exist to the best of our knowledge, making this technique unique and necessary. The influence of the AC kHz operating frequency is important because many plasma jet designs used throughout the world operate at different frequency which changes the time between the ionization waves and hence the leftover species densities and stability of the plasma. Results for our jet show a linear operating regime between 20 and 50 kHz where the ionization waves are stable and the temperature increases linearly by 25 K. The charge deposition and induced electric fields do not increase significantly but the surface area does increase due to an extended surface propagation. Additionally, temperature mapping using a 100 µm GaAs probe of the plasma plume area has revealed a mild heat exchange causing a heating of several degrees of the helium core while the surrounding air slightly cools. This peculiarity is also observed without plasma in the gas plume.