Evolution of the critical oxygen tension

Chang, A.; Compañ Moreno, V.; Weissman, BA. (2018). Evolution of the critical oxygen tension. Contact Lens Spectrum. 33(3):36-39. http://hdl.handle.net/10251/121358S363933

Transapical endovascular repair of iatrogenic type A aortic dissection

Intraoperative iatrogenic type A aortic dissection is a rare but known complication of cardiac surgery, with an incidence of 0.06% to 0.23%. Results are frequently catastrophic. The endovascular approach has made advances as an alternative treatment for aortic disease. However, the apical approach for transcatheter thoracic endovascular aortic repair is not well known. We present a 5-year follow-up of a case of iatrogenic type A aortic dissection after minimally invasive mitral valve repair successfully resolved by medical stabilization and subsequent transapical thoracic endovascular aortic repair

Corneal Equilibrium Flux as a Function of Corneal Surface Oxygen Tension

[EN] Purpose Oxygen is essential for aerobic mammalian cell physiology. Oxygen tension (PO2) should reach a minimum at some position within the corneal stroma, and oxygen flux should be zero, by definition, at this point as well. We found the locations and magnitudes of this ¿corneal equilibrium flux¿ (xmin) and explored its physiological implications. Methods We used an application of the Monod kinetic model to calculate xmin for normal human cornea as anterior surface PO2 changes from 155 to 20 mmHg. Results We find that xmin deepens, broadens, and advances from 1.25 ¿m above the endothelial¿aqueous humor surface toward the epithelium (reaching a position 320 ¿m above the endothelial¿aqueous humor surface) as anterior corneal surface PO2 decreases from 155 to 20 mmHg. Conclusions Our model supports an anterior corneal oxygen flux of 9 ¿L O2 · cm¿2 · h¿1 and an epithelial oxygen consumption of approximately 4 ¿L O2 · cm¿2 · h¿1. Only at the highest anterior corneal PO2 does our model predict that oxygen diffuses all the way through the cornea to perhaps reach the anterior chamber. Of most interest, corneal oxygen consumption should be supported down to a corneal surface PO2 of 60 to 80 mmHg but declines below this range. We conclude that the critical oxygen tension for hypoxia induced corneal swelling is more likely this range rather than a fixed value.Compañ Moreno, V.; Aguilella-Arzo, M.; Weissman, BA. (2017). Corneal Equilibrium Flux as a Function of Corneal Surface Oxygen Tension. Optometry and Vision Science. 94(6):672-679. doi:10.1097/OPX.0000000000001083S67267994

Modeling Corneal Oxygen with Scleral Gas Permeable Lens Wear

[EN] Purpose. The main goal of this current work is to use an updated calculation paradigm, and updated boundary conditions, toprovidetheoreticalguidelinestoassisttheclinicianwhosegoalistoimprovehisorherscleralgaspermeable(GP)contact lens wearing patients¿ anterior corneal oxygen supply. Methods. Our model uses a variable value of corneal oxygen consumption developed through Monod equations that disallows negative oxygen tensions within the stroma to predict oxygen tension at the anterior corneal surface of scleral GP contact lens wearing eyes, and to describe oxygen tension and flux profiles, for various boundary conditions, through the lens, tears, and cornea. We use several updated tissue and boundary parameters in our model. Tear exchange with GP scleral lenses is considered nonexistent in this model. Results. The majority of current scleral GP contact lenses should produce some levels of corneal hypoxia under open eye conditions.Onlylensesproducingthethinnestoftearvaultsshouldresultinanteriorcornealsurfaceoxygentensionsgreaterthana presumed critical oxygen tension of 100 mmHg. We also find that corneal oxygen tension and flux are each more sensitive to modification in tear vault than to changes in lens oxygen permeability, within the ranges of current clinical manipulation. Conclusions. Our study suggests that clinicians would be prudent to prescribe scleral GP lenses manufactured from higher oxygen permeability materials and especially to fit without excessive corneal clearance. (Optom Vis Sci 2016;93:00Y00Compañ Moreno, V.; Aguilella-Arzo, M.; Edrington, TB.; Weissman, BA. (2016). Modeling Corneal Oxygen with Scleral Gas Permeable Lens Wear. Optometry and Vision Science. 93(11):1339-1348. doi:10.1097/OPX.0000000000000988S13391348931

The application of human factors in wake vortex encounter flight simulations for the reduction of flight upset risk and startle response

The current top safety risk concern for commercial air travel in Europe is known as “Flight Upset”. This term, also known as “Loss of Control in Flight”, entails the flight crew suddenly finding themselves in an unexpected, complex, and even confusing situation that if not resolved quickly can lead to a major accident. Accidents such as AF447 and the two B737 Max accidents fall into this category. An undesirable aspect of such events is known as the “startle response”, wherein one or both flight crew, finding themselves in dire and dangerous conditions, may experience ‘startle’, which temporarily affects their cognitive functioning. This may only last half a minute, but its effect can have a severe impact on the survivability of such events. A Horizon 2020 research project called SAFEMODE, which aims to integrate Human Factors techniques into a unified framework for designers in aviation and maritime domains, is exploring the use of state-of-the-art flight simulation facilities to measure pilot performance in severe wake turbulence events, which can induce the startle effect. This is part of a broader use case within SAFEMODE to validate the design of a new Wake Vortex Air Traffic Alert for the Cruise phase of flight. A tactical short-term alert to the Flight Crew, ahead of the wake encounter, is seen as beneficial to reduce the startle effect and support the appropriate management of these conflicts. The envisaged risk-alerting logic relies on a ground-based predictor, connected to the Air Traffic Control system, displaying an alert to the En-route Air Traffic Controllers, who can then provide a cautionary advisory to the Flight Crew so they can take appropriate actions.The cockpit flight simulations involve type-rated flight crews in realistic and representative cruise flight conditions, using a Type VI Boeing 737-800 full flight motion-based simulator (also used for Upset Prevention and Recovery training programs). During the simulation runs, pilots are exposed to simulated wake vortex encounters, corresponding to a strong wake-induced upset (between 30 and 40 degrees of bank), with or without prior ATC wake caution, and varying the initial direction of roll between left and right to limit the simulation training effect.Human Factors measurements include workload, situation awareness, trust, acceptability-based user feedback, as well as psychophysiological measures such as eye-tracking and Electro-Dermal Activity (EDA). In particular, eye-tracking is expected to support the refined determination of the sequence of actions before and after detection, and the reaction of flight crews to the en-route ATC Wake alert.A cockpit flight simulation, via combining the analyses of psychophysiological measures, flight parameters, expert observations and subjective pilot feedback, enables evaluation of Flight Crews performance in preparing for, managing or avoiding wake encounter upsets with the new ATC wake alerts, showing the net safety benefits. Early results indicate that the simulations can indeed induce startle effect, and that repeated exposure enables flight crew to overcome it and manage the situation in a more measured and controlled fashion

Plano Ambiental Inter-Sectorial Ambiente e Agricultura, Silvicultura e Pecuária

Cabo Verde é um país ecologicamente frágil e de fracos recursos naturais. A satisfação das necessidades básicas do Homem exige que sejam bem definidas orientações estratégicas de aproveitamento e uma aplicação optimizada dos recursos naturais a favor do desenvolvimento de actividades económicas. Desde a independência, os sucessivos Governos Cabo-verdianos têm-se mostrado preocupados com a questão da preservação dos ecossistemas e com o enquadramento dos organismos vocacionados para a gestão ambiental. Na estratégia expressa nas Grandes Opções para do Desenvolvimento (2002), o ambiente é um dos temas mais importantes. Projecta-se uma sociedade dotada de um sentimento profundo para o ambiente e de uma consciência ecológica desenvolvida sendo as medidas de preservação encaradas de forma sistémica e transversal, pretendendo-se que sejam equitativas. O segundo Plano de Acção Nacional para o Ambiente (PANA II) constitui a concretização destas políticas e define as orientações estratégicas de aproveitamento dos recursos naturais bem como os seus efeitos sobre a gestão sustentável das actividades económicas. É um documento orientador de um processo continuo caracterizado por uma dinâmica própria e que nos próximos 10 anos (2004-2014), servirá de base de trabalho, permitindo um desenvolvimento Cabo-verdiano sustentável e harmonioso, garantindo um ambiente sadio. A elaboração do PANA II foi um processo complexo com o objectivo de assegurar o envolvimento dos parceiros e estabelecer as respectivas interligações entre os vários níveis. Incluído neste processo esteve a elaboração dos nove Planos Ambientais Inter-sectoriais (PAIS). Esses PAIS incluem as preocupações e planos de todos os ministérios e agências envolvidas em sub-sectores específicos. Assim resultarão em programas e actividades coerentes, transversais e com uma visão clara sobre o desenvolvimento sustentável. Este documento apresenta os resultados dos trabalhos e planificação dos parceiros no sector Ambiente e Agricultura.Governo dos Países Baixo

MYC is essential for the formation and maintenance of germinal centers

Germinal centers (GC) are sites of intense B cell proliferation, central for T cell dependent antibody responses. However, the role of MYC, a key cell cycle regulator, in this process has been questioned. Here, we identified MYC positive B cell subpopulations in immature and mature GCs, and show through genetic ablation of Myc that they play indispensable roles in GC formation and maintenance. The identification of these functionally critical cellular subsets has important implications for human B cell lymphomagenesis, which mostly originates from GC B cells and frequently involves MYC chromosomal translocations. As these translocations are generally dependent on transcription of the recombining partner loci, the MYC positive GC subpopulations may be at a particularly high risk for malignant transformation

Multiple functional risk variants in a SMAD7 enhancer implicate a colorectal cancer risk haplotype

Genome-wide association studies (GWAS) of colorectal cancer (CRC) have led to the identification of a number of common variants associated with modest risk. Several risk variants map within the vicinity of TGFβ/BMP signaling pathway genes, including rs4939827 within an intron of SMAD7 at 18q21.1. A previous study implicated a novel SNP (novel 1 or rs58920878) as a functional variant within an enhancer element in SMAD7 intron 4. In this study, we show that four SNPs including novel 1 (rs6507874, rs6507875, rs8085824, and rs58920878) in linkage disequilibrium (LD) with the index SNP rs4939827 demonstrate allele-specific enhancer effects in a large, multi-component enhancer of SMAD7. All four SNPs demonstrate allele-specific protein binding to nuclear extracts of CRC cell lines. Furthermore, some of the risk-associated alleles correlate with increased expression of SMAD7 in normal colon tissues. Finally, we show that the enhancer is responsive to BMP4 stimulation. Taken together, we propose that the associated CRC risk at 18q21.1 is due to four functional variants that regulate SMAD7 expression and potentially perturb a BMP negative feedback loop in TGFβ/BMP signaling pathways

Effects of 12 Months of Vagus Nerve Stimulation in Treatment-Resistant Depression: A Naturalistic Study

Background: The need for effective, long-term treatment for recurrent or chronic, treatment-resistant depression is well established. Methods: This naturalistic follow-up describes outpatients with nonpsychotic major depressive (n = 185) or bipolar (I or II) disorder, depressed phase (n = 20) who initially received 10 weeks of active (n = 110) or sham vagus nerve stimulation (VNS) (n = 95). The initial active group received another 9 months, while the initial sham group received 12 months of VNS. Participants received antidepressant treatments and VNS, both of which could be adjusted. Results: The primary analysis (repeated measures linear regression) revealed a significant reduction in 24-item Hamilton Rating Scale for Depression (HRSD24) scores (average improvement, .45 points [SE = .05] per month (p \u3c .001). At exit, HRSD24 response rate was 27.2% (55/202); remission rate (HRSD24 ≤ 9) was 15.8% (32/202). Montgomery Asberg Depression Rating Scale (28.2% [57/202]) and Clinical Global Impression-Improvement (34.0% [68/200]) showed similar response rates. Voice alteration, dyspnea, and neck pain were the most frequently reported adverse events. Conclusions: These 1-year open trial data found VNS to be well tolerated, suggesting a potential long-term, growing benefit in treatment-resistant depression, albeit in the context of changes in depression treatments. Comparative long-term data are needed to determine whether these benefits can be attributed to VNS