Global impacts of an extreme solar particle event under different geomagnetic field strengths.

Solar particle events (SPEs) are short-lived bursts of high-energy particles from the solar atmosphere and are widely recognized as posing significant economic risks to modern society. Most SPEs are relatively weak and have minor impacts on the Earth's environment, but historic records contain much stronger SPEs which have the potential to alter atmospheric chemistry, impacting climate and biological life. The impacts of such strong SPEs would be far more severe when the Earth's protective geomagnetic field is weak, such as during past geomagnetic excursions or reversals. Here, we model the impacts of an extreme SPE under different geomagnetic field strengths, focusing on changes in atmospheric chemistry and surface radiation using the atmosphere-ocean-chemistry-climate model SOCOL3-MPIOM and the radiation transfer model LibRadtran. Under current geomagnetic conditions, an extreme SPE would increase NOx concentrations in the polar stratosphere and mesosphere, causing reductions in extratropical stratospheric ozone lasting for about a year. In contrast, with no geomagnetic field, there would be a substantial increase in NOx throughout the entire atmosphere, resulting in severe stratospheric ozone depletion for several years. The resulting ground-level ultraviolet (UV) radiation would remain elevated for up to 6 y, leading to increases in UV index up to 20 to 25% and solar-induced DNA damage rates by 40 to 50%. The potential evolutionary impacts of past extreme SPEs remain an important question, while the risks they pose to human health in modern conditions continue to be underestimated.

Stability of influenza A virus in droplets and aerosols is heightened by the presence of commensal respiratory bacteria.

Aerosol transmission remains a major challenge for control of respiratory viruses, particularly those causing recurrent epidemics, like influenza A virus (IAV). These viruses are rarely expelled alone, but instead are embedded in a consortium of microorganisms that populate the respiratory tract. The impact of microbial communities and inter-pathogen interactions upon stability of transmitted viruses is well-characterized for enteric pathogens, but is under-studied in the respiratory niche. Here, we assessed whether the presence of five different species of commensal respiratory bacteria could influence the persistence of IAV within phosphate-buffered saline and artificial saliva droplets deposited on surfaces at typical indoor air humidity, and within airborne aerosol particles. In droplets, presence of individual species or a mixed bacterial community resulted in 10- to 100-fold more infectious IAV remaining after 1 h, due to bacterial-mediated flattening of drying droplets and early efflorescence. Even when no efflorescence occurred at high humidity or the bacteria-induced changes in droplet morphology were abolished by aerosolization instead of deposition on a well plate, the bacteria remained protective. Staphylococcus aureus and Streptococcus pneumoniae were the most stabilizing compared to other commensals at equivalent density, indicating the composition of an individual's respiratory microbiota is a previously unconsidered factor influencing expelled virus persistence.IMPORTANCEIt is known that respiratory infections such as coronavirus disease 2019 and influenza are transmitted by release of virus-containing aerosols and larger droplets by an infected host. The survival time of viruses expelled into the environment can vary depending on temperature, room air humidity, UV exposure, air composition, and suspending fluid. However, few studies consider the fact that respiratory viruses are not alone in the respiratory tract-we are constantly colonized by a plethora of bacteria in our noses, mouth, and lower respiratory system. In the gut, enteric viruses are known to be stabilized against inactivation and environmental decay by gut bacteria. Despite the presence of a similarly complex bacterial microbiota in the respiratory tract, few studies have investigated whether viral stabilization could occur in this niche. Here, we address this question by investigating influenza A virus stabilization by a range of commensal bacteria in systems representing respiratory aerosols and droplets.

The neuraminidase activity of influenza A virus determines the strain-specific sensitivity to neutralization by respiratory mucus.

IMPORTANCE: The respiratory tract of humans is constantly exposed to potentially harmful agents, such as small particles or pathogens, and thus requires protective measures. Respiratory mucus that lines the airway epithelia plays a major role in the prevention of viral infections by limiting the mobility of viruses, allowing subsequent mucociliary clearance. Understanding the interplay between respiratory mucus and viruses can help elucidate host and virus characteristics that enable the initiation of infection. Here, we tested a panel of primary influenza A viruses of avian or human origin for their sensitivity to mucus derived from primary human airway cultures and found that differences between virus strains can be mapped to viral neuraminidase activity. We also show that binding of influenza A viruses to decoy receptors on highly glycosylated mucus components constitutes the major inhibitory function of mucus against influenza A viruses.

Expiratory Aerosol pH: The Overlooked Driver of Airborne Virus Inactivation.

Respiratory viruses, including influenza virus and SARS-CoV-2, are transmitted by the airborne route. Air filtration and ventilation mechanically reduce the concentration of airborne viruses and are necessary tools for disease mitigation. However, they ignore the potential impact of the chemical environment surrounding aerosolized viruses, which determines the aerosol pH. Atmospheric aerosol gravitates toward acidic pH, and enveloped viruses are prone to inactivation at strong acidity levels. Yet, the acidity of expiratory aerosol particles and its effect on airborne virus persistence have not been examined. Here, we combine pH-dependent inactivation rates of influenza A virus (IAV) and SARS-CoV-2 with microphysical properties of respiratory fluids using a biophysical aerosol model. We find that particles exhaled into indoor air (with relative humidity ≥ 50%) become mildly acidic (pH ∼ 4), rapidly inactivating IAV within minutes, whereas SARS-CoV-2 requires days. If indoor air is enriched with nonhazardous levels of nitric acid, aerosol pH drops by up to 2 units, decreasing 99%-inactivation times for both viruses in small aerosol particles to below 30 s. Conversely, unintentional removal of volatile acids from indoor air may elevate pH and prolong airborne virus persistence. The overlooked role of aerosol acidity has profound implications for virus transmission and mitigation strategies.

Surface tension models for binary aqueous solutions: a review and intercomparison.

The liquid-air surface tension of aqueous solutions is a fundamental quantity in multi-phase thermodynamics and fluid dynamics and thus relevant in many scientific and engineering fields. Various models have been proposed for its quantitative description. This Perspective gives an overview of the most popular models and their ability to reproduce experimental data of ten binary aqueous solutions of electrolytes and organic molecules chosen to be representative of different solute types. In addition, we propose a new model which reproduces sigmoidal curve shapes (Sigmoid model) to empirically fit experimental surface tension data. The surface tension of weakly surface-active substances is well reproduced by all models. In contrast, only few models successfully model the surface tension of aqueous solutions with strongly surface-active substances. For substances with a solubility limit, usually no experimental data is available for the surface tension of supersaturated solutions and the pure liquid solute. We discuss ways in which these can be estimated and emphasize the need for further research. The newly developed Sigmoid model best reproduces the surface tension of all tested solutions and can be recommended as a model for a broad range of binary mixtures and over the entire concentration range.

Experience with "Select Crowd Review" in Peer Review for The Thoracic and Cardiovascular Surgeon: 1-Year Experience.

OBJECTIVE: To evaluate the experience with a new peer review method, "Select Crowd Review" (SCR): anonymized PDFs of manuscripts are accessible to a reviewer crowd via an online platform. It has access for 10 days to enter anonymized comments directly into the manuscript. A SCR-Editor summarizes the annotations, giving a recommendation. Both reviewed PDF and summary are sent back to authors. Upon submission, authors are given a choice to accept or decline SCR. DESIGN: All manuscript submissions since introduction in July 2021 until July 2022 were analyzed regarding acceptance and quality. Manuscripts were sent to a crowd of 45 reviewers and regular double-blinded peer review at the same time. Efficiency and performance of the crowd's reviews were compared with those of regular review. For thoracic manuscripts, a crowd was not yet available. RESULTS: SCR was accepted by the authors for 73/179 manuscripts (40.8%). After desk rejections, 51 cardiac manuscripts entered SCR. For five manuscripts, the crowd did not respond. In all remaining papers, the crowd's recommendation concurred with that of the normal reviewers. Regular peer review took up to 6 weeks. Twelve manuscripts underwent repeated SCR after revision. A median of 2 (0-9) crowd members sent in reviews. In revisions, average response was one reviewer responding. CONCLUSION: SCR encountered good acceptance by authors. As the first experience showed concordant recommendations compared with traditional review, we have extended SCR to thoracic manuscripts for more experience. SCR may become the sole review method for eligible manuscripts. Efficiency should be increased, especially for re-review of revisions.

Electrodynamic balance-mass spectrometry reveals impact of oxidant concentration on product composition in the ozonolysis of oleic acid.

The chemical and physical properties of atmospheric aerosol particles change upon oxidative ageing, influencing their interaction with radiation, their propensity to serve as nuclei for cloud condensation and ice formation, and their adverse effects on human health. The investigation of atmospheric aerosol oxidation processes is complicated by low oxidant concentrations and long timescales, which are difficult to represent in laboratory studies. Experimental work often attempts to compensate for short timescales with elevated concentrations of oxidative agents, assuming that the ageing progress depends only on the oxidant exposure, i.e. on the product of oxidant concentration and time, [Ox] × t, and not on [Ox] or t independently. The application of electrodynamic balance-mass spectrometry of single particles allows the validity of this assumption to be investigated, since it provides information on the molecular composition of aerosol particles for a wide range of reaction durations under well-defined oxidation conditions. Here, we demonstrate the capabilities of a new setup on levitated oleic acid droplets reacting with ozone at mixing ratios of 0.2 and 15 ppm, i.e. spanning almost two orders of magnitude in [Ox]. We show that the reactive removal of oleic acid can be accurately expressed as a function of ozone exposure [Ox] × t, whereas the product concentrations depend on [Ox] and t independently. As the underlying reason for the breakdown of the exposure metric, we suggest a competition between evaporation of volatile first-generation products and their accretion reactions with reactive Criegee intermediates, converting them into low-volatility dimers and oligomers. This hypothesis is supported by kinetic model simulations using the aerosol process model KM-SUB, which explicitly resolves the competition between evaporation and secondary chemistry as a function of the experimental timescale and ozone mixing ratio. The model successfully reproduces final product distributions. The findings are further supported by the recorded changes of droplet sizes during oxidation. As a heuristic, the breakdown of the exposure metric in a chemical reaction system is possible, when competition between first- and second-order processes of reactive intermediates determines important system properties.

Augmented Renal Clearance of Vancomycin in Suspected Sepsis: Single-Center, Retrospective Pediatric Cohort.

OBJECTIVES: To identify associations between augmented renal clearance (ARC) in pediatric patients treated for suspected sepsis and vancomycin pharmacokinetics. ARC has been associated with lower serum drug levels in both adult and pediatric cohorts for multiple drugs. We hypothesize that presence of ARC is associated with subtherapeutic initial vancomycin trough level (VTL). DESIGN: Retrospective study, with patients divided into two groups based on the presence of ARC (estimated glomerular filtration rate [eGFR] above 130 mL/min/1.73 m2) in comparison with VTL. Multivariable logistic regression analysis was performed to evaluate the association between eGFR and subtherapeutic VTL. SETTING: Tertiary children's hospital. PATIENTS: Hospitalized children (0-18 yr) initiated on empiric vancomycin therapy for suspected sepsis. INTERVENTIONS: Retrospective measurement of VTL, eGFR, and clinical variables. MEASUREMENTS AND MAIN RESULTS: Seventy-three patients were treated with empiric vancomycin for sepsis. ARC was present in 32 patients (44%). Subtherapeutic first VTL was present in 40 patients (55%). Higher eGFR was independently associated with subtherapeutic VTL in the multivariable logistic regression analysis. CONCLUSIONS: Subtherapeutic VTL is associated with ARC in our single-center retrospective cohort of children with suspected sepsis. This problem may present a potential risk of treatment failure in Gram-positive sepsis or longer time to clinical response. Prospective studies to investigate the clinical significance and effect of optimizing vancomycin dose in patients with ARC are recommended.

Phenotypic and molecular dissection of metaplastic breast cancer and the prognostic implications.

Metaplastic breast carcinoma (MBC) is relatively rare but accounts for a significant proportion of global breast cancer mortality. This group is extremely heterogeneous and by definition exhibits metaplastic change to squamous and/or mesenchymal elements, including spindle, squamous, chondroid, osseous, and rhabdomyoid features. Clinically, patients are more likely to present with large primary tumours (higher stage), distant metastases, and overall, have shorter 5-year survival compared to invasive carcinomas of no special type. The current World Health Organisation (WHO) diagnostic classification for this cancer type is based purely on morphology - the biological basis and clinical relevance of its seven sub-categories are currently unclear. By establishing the Asia-Pacific MBC (AP-MBC) Consortium, we amassed a large series of MBCs (n = 347) and analysed the mutation profile of a subset, expression of 14 breast cancer biomarkers, and clinicopathological correlates, contextualising our findings within the WHO guidelines. The most significant indicators of poor prognosis were large tumour size (T3; p = 0.004), loss of cytokeratin expression (lack of staining with pan-cytokeratin AE1/3 antibody; p = 0.007), EGFR overexpression (p = 0.01), and for 'mixed' MBC, the presence of more than three distinct morphological entities (p = 0.007). Conversely, fewer morphological components and EGFR negativity were favourable indicators. Exome sequencing of 30 cases confirmed enrichment of TP53 and PTEN mutations, and intriguingly, concurrent mutations of TP53, PTEN, and PIK3CA. Mutations in neurofibromatosis-1 (NF1) were also overrepresented [16.7% MBCs compared to ∼5% of breast cancers overall; enrichment p = 0.028; mutation significance p = 0.006 (OncodriveFM)], consistent with published case reports implicating germline NF1 mutations in MBC risk. Taken together, we propose a practically minor but clinically significant modification to the guidelines: all WHO_1 mixed-type tumours should have the number of morphologies present recorded, as a mechanism for refining prognosis, and that EGFR and pan-cytokeratin expression are important prognostic markers. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Constraining Atmospheric Selenium Emissions Using Observations, Global Modeling, and Bayesian Inference.

Selenium (Se) is an essential dietary element for humans and animals, and the atmosphere is an important source of Se to soils. However, estimates of global atmospheric Se fluxes are highly uncertain. To constrain these uncertainties, we use a global model of atmospheric Se cycling and a database of more than 600 sites where Se in aerosol has been measured. Applying Bayesian inference techniques, we determine the probability distributions of global Se emissions from the four major sources: anthropogenic activities, volcanoes, marine biosphere, and terrestrial biosphere. Between 29 and 36 Gg of Se are emitted to the atmosphere every year, doubling previous estimates of emissions. Using emission parameters optimized by aerosol network measurements, our model shows good agreement with the aerosol Se observations (R2 = 0.66), as well as with independent aerosol (0.59) and wet deposition measurements (0.57). Both model and measurements show a decline in Se over North America in the last two decades because of changes in technology and energy policy. Our results highlight the role of the ocean as a net atmospheric Se sink, with around 7 Gg yr-1 of Se transferred from land through the atmosphere. The constrained Se emissions represent a substantial step forward in understanding the global Se cycle.

Peer-teaching at the University of Rwanda - a qualitative study based on self-determination theory.

BACKGROUND: Peer-teaching is an educational format in which one student teaches one, or more, fellow students. Self-determination theory suggests that intrinsic motivation increases with the enhancement of autonomy, competence and relatedness. AIMS: This qualitative study sought to explore and better understand the lived experiences, attitudes and perceptions of medical students as peer-teachers at the University of Rwanda when participating in a peer-learning intervention in the pediatric department. METHODS: Students participated in a 3-h peer-taught symposium, supervised by a pediatric specialist or resident. Students worked in small groups to deliver a short didactic presentation related to acute illness in children. The symposium prepared the students for simulation-based teaching activities. In-depth, semi-structured, interviews were then employed to explore the students' experiences of the peer-teaching symposium. We specifically aimed to scaffold the analysis of these experiences on the themes of autonomy, competence and relatedness. RESULTS: Saturation was achieved after interviews with ten students. Students described developing their own autonomous learning strategies, but despite developing this autonomy had a desire for support in the delivery of the sessions. Competence was developed through enhanced learning of the material, developing teaching skills and confidence in public speaking. Students valued the different aspects of relatedness that developed through preparing and delivering the peer-teaching. Several other themes were identified during the interviews, which are not described here, namely; i. Satisfaction with peer-teaching; ii. Peer-teaching as a concept; iii. Practical issues related to the peer-teaching session, and iv. Teaching style from faculty. CONCLUSIONS: This is the first study to assess peer-learning activities in Rwanda. It has used qualitative methods to deeply explore the lived experiences, attitudes and perceptions of medical students. The peer-teaching strategy used here demonstrates the potential to enhance intrinsic motivation while increasing knowledge acquisition and teaching skills. We postulate that students in resource-limited settings, similar to Rwanda, would benefit from peer-teaching activities, and in doing so could enhance their intrinsic motivation.

A Versatile Protein and Cell Patterning Method Suitable for Long-Term Neural Cultures.

Herein, we present an easy-to-use protein and cell patterning method relying solely on pipetting, rinsing steps and illumination with a desktop lamp, which does not require any expensive laboratory equipment, custom-built hardware or delicate chemistry. This method is based on the adhesion promoter poly(allylamine)-grafted perfluorophenyl azide, which allows UV-induced cross-linking with proteins and the antifouling molecule poly(vinylpyrrolidone). Versatility is demonstrated by creating patterns with two different proteins and a polysaccharide directly on plastic well plates and on glass slides, and by subsequently seeding primary neurons and C2C12 myoblasts on the patterns to form islands and mini-networks. Patterning characterization is done via immunohistochemistry, Congo red staining, ellipsometry, and infrared spectroscopy. Using a pragmatic setup, patterning contrasts down to 5 µm and statistically significant long-term stability superior to the gold standard poly(l-lysine)-grafted poly(ethylene glycol) could be obtained. This simple method can be used in any laboratory or even in classrooms and its outstanding stability is especially interesting for long-term cell experiments, e.g., for bottom-up neuroscience, where well-defined microislands and microcircuits of primary neurons are studied over weeks.

Easy to Apply Polyoxazoline-Based Coating for Precise and Long-Term Control of Neural Patterns.

Arranging cultured cells in patterns via surface modification is a tool used by biologists to answer questions in a specific and controlled manner. In the past decade, bottom-up neuroscience emerged as a new application, which aims to get a better understanding of the brain via reverse engineering and analyzing elementary circuitry in vitro. Building well-defined neural networks is the ultimate goal. Antifouling coatings are often used to control neurite outgrowth. Because erroneous connectivity alters the entire topology and functionality of minicircuits, the requirements are demanding. Current state-of-the-art coating solutions such as widely used poly(l-lysine)-g-poly(ethylene glycol) (PLL-g-PEG) fail to prevent primary neurons from making undesired connections in long-term cultures. In this study, a new copolymer with greatly enhanced antifouling properties is developed, characterized, and evaluated for its reliability, stability, and versatility. To this end, the following components are grafted to a poly(acrylamide) (PAcrAm) backbone: hexaneamine, to support spontaneous electrostatic adsorption in buffered aqueous solutions, and propyldimethylethoxysilane, to increase the durability via covalent bonding to hydroxylated culture surfaces and antifouling polymer poly(2-methyl-2-oxazoline) (PMOXA). In an assay for neural connectivity control, the new copolymer's ability to effectively prevent unwanted neurite outgrowth is compared to the gold standard, PLL-g-PEG. Additionally, its versatility is evaluated on polystyrene, glass, and poly(dimethylsiloxane) using primary hippocampal and cortical rat neurons as well as C2C12 myoblasts, and human fibroblasts. PAcrAm-g-(PMOXA, NH2, Si) consistently outperforms PLL-g-PEG with all tested culture surfaces and cell types, and it is the first surface coating which reliably prevents arranged nodes of primary neurons from forming undesired connections over the long term. Whereas the presented work focuses on the proof of concept for the new antifouling coating to successfully and sustainably prevent unwanted connectivity, it is an important milestone for in vitro neuroscience, enabling follow-up studies to engineer neurologically relevant networks. Furthermore, because PAcrAm-g-(PMOXA, NH2, Si) can be quickly applied and used with various surfaces and cell types, it is an attractive extension to the toolbox for in vitro biology and biomedical engineering.

Kinetic Limitation to Inorganic Ion Diffusivity and to Coalescence of Inorganic Inclusions in Viscous Liquid-Liquid Phase-Separated Particles.

Mixed organic/inorganic aerosols may undergo liquid-liquid phase separation (LLPS) when the relative humidity drops in the atmosphere. Phase-separated particles adopt different morphologies, which will have different consequences for atmospheric chemistry and climate. Recent laboratory studies on submicron particles led to speculation whether LLPS observed for larger drops might actually be suppressed in smaller droplets. Here, we report on micron-sized droplets of a ternary mixture of ammonium sulfate (AS), carminic acid, and water at different temperatures, which were exposed to typical atmospheric drying rates ranging from 0.34 to 5.0% RH min-1. Our results reveal that increasing the drying rate and lowering the temperature results in different morphologies after LLPS and may suppress the growth and coalescence of the inorganic-rich phase inclusions due to kinetic limitations in a viscous matrix. The coalescence time was used to estimate the viscosity of the organic-rich phase within a factor of 20, and based on the Stokes-Einstein relationship, we estimated AS diffusivity. Furthermore, we evaluated the initial growth of inclusions to quantitatively determine the AS diffusivity in the organic-rich phase, which is about 10-8 cm2 s-1 at room temperature. Extrapolation of diffusivity to lower temperatures using estimations for the diffusion activation energy leads us to conclude that the growth of the inorganic phase is not kinetically impeded for tropospheric submicron particles larger than 100 nm.

Stimulation of Eryptosis by Caspofungin.

BACKGROUND/AIMS: The echinocandin antifungal agent caspofungin has been shown to trigger apoptosis of fungal cells. Beyond that, caspofungin is toxic for host mitochondria. Even though lacking mitochondria, erythrocytes may enter apoptosis-like suicidal erythrocyte death or eryptosis, characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine translocation to the erythrocyte surface. Signaling involved in triggering of eryptosis include increase of cytosolic Ca2+ activity ([Ca2+]i), oxidative stress, ceramide, caspase activation and/or activation of p38 kinase, protein kinase C, and casein kinase. The present study explored, whether caspofungin induces eryptosis and, if so, to shed some light on the cellular mechanisms involved. METHODS: Flow cytometry was employed to determine phosphatidylserine exposure at the cell surface from annexin-V-binding, cell volume from forward scatter, [Ca2+]i from Fluo3-fluorescence, ROS formation from DCFDA dependent fluorescence, and ceramide abundance utilizing specific antibodies. Hemolysis was quantified from hemoglobin concentration in the supernatant. RESULTS: A 48 hours exposure of human erythrocytes to caspofungin (≥ 30 µg/ml) significantly increased the percentage of annexin-V-binding cells, significantly decreased forward scatter, significantly enhanced hemolysis, but did not significantly increase Fluo3-fluorescence, DCFDA fluorescence or ceramide abundance. The effect of caspofungin on annexin-V-binding was not significantly blunted by removal of extracellular Ca2+, by inhibition of caspases with pancaspase inhibitor zVAD (10 µM), or by addition of the antioxidant N-acetyl-cysteine (1 mM), p38 kinase inhibitor SB203580 (2 µM) or protein kinase C inhibitor staurosporine (1 µM). The effect of caspofungin on annexin-V-binding was, however, significantly blunted in the presence of casein kinase inhibitor D4476 (10 µM). CONCLUSIONS: Caspofungin triggers cell shrinkage and phospholipid scrambling of the erythrocyte cell membrane, an effect possibly involving activation of casein kinase.

Anidulafungin-Induced Suicidal Erythrocyte Death.

BACKGROUND/AIMS: The novel antifungal drug Anidulafungin is used for the treatment of diverse fungal infections including candidiasis and aspergillosis. The traditional antifungal drug amphotericin B has previously been shown to trigger eryptosis, the suicidal death of erythrocytes characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine translocation to the erythrocyte surface. Triggers of eryptosis include increase of cytosolic Ca2+ activity ([Ca2+]i), oxidative stress, ceramide, activated protein kinase C (PKC), casein kinase 1α or p38 kinase and activated caspases. Inhibitors of eryptosis include nitric oxide (NO). The present study explored, whether Anidulafungin induces eryptosis. METHODS: Flow cytometry was employed to estimate phosphatidylserine abundance at the erythrocyte surface from annexin-V-binding, cell volume from forward scatter, [Ca2+]i from Fluo3-fluorescence, abundance of reactive oxygen species (ROS) from DCFDA dependent fluorescence, and ceramide abundance at the erythrocyte surface utilizing specific antibodies. Hemolysis was quantified by measuring haemoglobin concentration in the supernatant. RESULTS: A 48 hours exposure of human erythrocytes to Anidulafungin (1.5 - 6 µg/ml) significantly increased hemolysis and the percentage of annexin-V-binding cells, and significantly decreased forward scatter. Anidulafungin (6 µg/ml) slightly, but significantly inceased Fluo3-fluorescence and the effect of Anidulafungin on annexin-V-binding was slightly, but significantly blunted by removal of extracellular Ca2+. The effect of Anidulafungin on annexin-V-binding was further significantly blunted by the p38 kinase inhibitor SB203580 (2 µM) and NO donor nitroprusside (1 µM). An increase of extracellular K+ concentration significantly blunted the effect of Anidulafungin on cell volume but not on annexin-V-binding. Anidulafungin rather decreased DCFDA fluorescence and the effect of Anidulafungin on annexin-V-binding was not significantly blunted by the antioxidant N-acetylcysteine (1 mM). Moreover, the effect of Anidulafungin on annexin-V-binding was not paralleled by significant increase of ceramide abundance and was not significantly blunted by PKC inhibitor staurosporine (1 µM), casein kinase 1α inhibitor D4476 (10 µM) or pancaspase inhibitor zVAD (10 µM). CONCLUSIONS: Anidulafungin triggers hemolysis and eryptosis with cell shrinkage and phospholipid scrambling of the erythrocyte cell membrane, an effect in part due to Ca2+ entry and activation of p38 kinase.

Micafungin-Induced Suicidal Erythrocyte Death.

BACKGROUND/AIMS: The antifungal drug Micafungin is used for the treatment of diverse fungal infections including candidiasis and aspergillosis. Side effects of Micafungin treatment include microangiopathic hemolytic anemia and thrombocytopenia with microvascular thrombosis. The development of thrombosis may be fostered by stimulation of eryptosis, the suicidal death of erythrocytes characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine translocation to the erythrocyte surface. Triggers of eryptosis include increase of cytosolic Ca2+ activity ([Ca2+]i), oxidative stress, ceramide, activated protein kinase C (PKC), casein kinase 1α or p38 kinase and activated caspases. The present study explored, whether Micafungin induces eryptosis. METHODS: Flow cytometry was employed to estimate phosphatidylserine abundance at the erythrocyte surface from annexin-V-binding, cell volume from forward scatter, [Ca2+]i from Fluo3-fluorescence, abundance of reactive oxygen species (ROS) from DCFDA dependent fluorescence, and ceramide abundance at the erythrocyte surface utilizing specific antibodies. Hemolysis was quantified by measuring haemoglobin concentration in the supernatant. RESULTS: A 48 hours exposure of human erythrocytes to Micafungin (10 - 25 µg/ml) significantly increased hemolysis and the percentage of annexin-V-binding cells, and significantly decreased forward scatter. Micafungin (25 µg/ml) did not significantly modify Fluo3-fluorescence, DCFDA fluorescence, or ceramide abundance. The effect of Micafungin on annexin-V-binding was not significantly modified by removal of extracellular Ca2+, by PKC inhibitor staurosporine (1 µM), p38 kinase inhibitor SB203580 (2 µM), casein kinase 1α inhibitor D4476 (10 µM) or pancaspase inhibitor zVAD (10 µM). CONCLUSIONS: Micafungin triggers hemolysis and eryptosis with cell shrinkage and phospholipid scrambling of the erythrocyte cell membrane.

Adding the implantable cardioverter-defibrillator to cardiac resynchronization therapy is associated with improved long-term survival in ischaemic, but not in non-ischaemic cardiomyopathy.

AIMS: Cardiac resynchronization therapy (CRT) improves symptoms, left ventricular function, and survival in patients with heart failure (HF) and wide QRS. The benefit of adding implantable cardioverter-defibrillator (ICD) backup is debated. We analysed the long-term outcome of patients with HF due to ischaemic cardiomyopathy (ICM) or non-ischaemic cardiomyopathy (NICM) treated with a CRT device with or without defibrillator backup. METHODS AND RESULTS: In this observational study, consecutive patients with an ejection fraction ≤35% and QRS width ≥120 ms receiving a CRT device at Aarhus University Hospital, Denmark from 2000 to 2010 were included. Baseline characteristics were retrieved from patient files and survival data were obtained from the Danish Civil Registration System. The primary outcome was all-cause mortality. The effect of ICD backup was estimated using Cox proportional hazards model, and the multivariate analyses were adjusted for a priori selected variables. We included 917 HF patients, 427 with NICM, and 490 with ICM. Median follow-up was 4.0 years. Adjusted hazard ratio (aHR) for all-cause mortality was 0.76 [95% confidence interval (95% CI), 0.60-0.97; P = 0.03] in all patients; 0.96 (95% CI, 0.60-1.51; P = 0.85) in patients with NICM, and 0.74 (95% CI, 0.56-0.97; P = 0.03) in patients with ICM. In patients with NICM, ICD backup seemed to be associated with improved survival among non-responders to CRT (P = 0.08), but not among responders (P = 0.61). CONCLUSION: Adding an ICD backup is associated with better survival in CRT recipients. This effect was evident among patients with ICM, but not in patients with NICM.

Ozone uptake on glassy, semi-solid and liquid organic matter and the role of reactive oxygen intermediates in atmospheric aerosol chemistry.

Heterogeneous and multiphase reactions of ozone are important pathways for chemical ageing of atmospheric organic aerosols. To demonstrate and quantify how moisture-induced phase changes can affect the gas uptake and chemical transformation of organic matter, we apply a kinetic multi-layer model to a comprehensive experimental data set of ozone uptake by shikimic acid. The bulk diffusion coefficients were determined to be 10(-12) cm(2) s(-1) for ozone and 10(-20) cm(2) s(-1) for shikimic acid under dry conditions, increasing by several orders of magnitude with increasing relative humidity (RH) due to phase changes from amorphous solid over semisolid to liquid. Consequently, the reactive uptake of ozone progresses through different kinetic regimes characterised by specific limiting processes and parameters. At high RH, ozone uptake is driven by reaction throughout the particle bulk; at low RH it is restricted to reaction near the particle surface and kinetically limited by slow diffusion and replenishment of unreacted organic molecules. Our results suggest that the chemical reaction mechanism involves long-lived reactive oxygen intermediates, likely primary ozonides or O atoms, which may provide a pathway for self-reaction and catalytic destruction of ozone at the surface. Slow diffusion and ozone destruction can effectively shield reactive organic molecules in the particle bulk from degradation. We discuss the potential non-orthogonality of kinetic parameters, and show how this problem can be solved by using comprehensive experimental data sets to constrain the kinetic model, providing mechanistic insights into the coupling of transport, phase changes, and chemical reactions of multiple species in complex systems.