[Percutaneous Resolution for Tricuspid Stenosis: Positive Outcomes Despite High Surgical Risk]. / Estenosis tricuspídea de bioprótesis tratada mediante implante valvular percutáneo: una solución segura para un paciente inusual.

We report a 31-year-old woman who was previously subjected to aortic, mitral, and tricuspid valve replacement in three different surgical episodes. She was admitted to our cardiology section with acute right heart failure symptoms. She was studied by echocardiography, right/left heart catheterization, cardiac CT scan and cardiac magnetic resonance. A severe tricuspid stenosis due to biological prosthesis dysfunction was diagnosed. Due to high operative risk and risk of postoperative right ventricular failure, the patient was rejected for cardiovascular surgery. We decided on a percutaneous tricuspid "valve in valve replacement". The procedure was done successfully by venous femoral approach, with a balloon expandable prosthesis. Tricuspid stenosis was corrected and the patient evolved with remission of heart failure symptoms.

Standardized spectral and radiometric calibration of consumer cameras.

Consumer cameras, particularly onboard smartphones and UAVs, are now commonly used as scientific instruments. However, their data processing pipelines are not optimized for quantitative radiometry and their calibration is more complex than that of scientific cameras. The lack of a standardized calibration methodology limits the interoperability between devices and, in the ever-changing market, ultimately the lifespan of projects using them. We present a standardized methodology and database (SPECTACLE) for spectral and radiometric calibrations of consumer cameras, including linearity, bias variations, read-out noise, dark current, ISO speed and gain, flat-field, and RGB spectral response. This includes golden standard ground-truth methods and do-it-yourself methods suitable for non-experts. Applying this methodology to seven popular cameras, we found high linearity in RAW but not JPEG data, inter-pixel gain variations >400% correlated with large-scale bias and read-out noise patterns, non-trivial ISO speed normalization functions, flat-field correction factors varying by up to 2.79 over the field of view, and both similarities and differences in spectral response. Moreover, these results differed wildly between camera models, highlighting the importance of standardization and a centralized database.

Absolute Radiometric Calibration of TESS-W and SQM Night Sky Brightness Sensors.

We develop a general optical model and describe the absolute radiometric calibration of the readings provided by two widely-used night sky brightness sensors based on irradiance-to-frequency conversion. The calibration involves the precise determination of the overall spectral sensitivity of the devices and also the constant G relating the output frequency of the light-to-frequency converter chip to the actual band-weighted and field-of-view averaged spectral radiance incident on the detector (brightness). From these parameters, we show how to define a rigorous astronomical absolute photometric system in which the sensor measurements can be reported in units of magnitudes per square arcsecond with precise physical meaning.

Pseudomonas syringae pv. tomato exploits light signals to optimize virulence and colonization of leaves.

Light is pervasive in the leaf environment, creating opportunities for both plants and pathogens to cue into light as a signal to regulate plant-microbe interactions. Light enhances plant defences and regulates opening of stomata, an entry point for foliar bacterial pathogens such as Pseudomonas syringae pv. tomato DC3000 (PsPto). The effect of light perception on gene expression and virulence was investigated in PsPto. Light induced genetic reprogramming in PsPto that entailed significant changes in stress tolerance and virulence. Blue light-mediated up-regulation of type three secretion system genes and red light-mediated down-regulation of coronatine biosynthesis genes. Cells exposed to white light, blue light or darkness before inoculation were more virulent when inoculated at dawn than dusk probably due to an enhanced entry through open stomata. Exposure to red light repressed coronatine biosynthesis genes which could lead to a reduced stomatal re-opening and PsPto entry. Photoreceptor were required for the greater virulence of light-treated and dark-treated PsPto inoculated at dawn as compared to dusk, indicating that these proteins sense the absence of light and contribute to priming of virulence in the dark. These results support a model in which PsPto exploits light changes to maximize survival, entry and virulence on plants.

Zernike analysis of all-sky night brightness maps.

All-sky night brightness maps (calibrated images of the night sky with hemispherical field-of-view (FOV) taken at standard photometric bands) provide useful data to assess the light pollution levels at any ground site. We show that these maps can be efficiently described and analyzed using Zernike circle polynomials. The relevant image information can be compressed into a low-dimensional coefficients vector, giving an analytical expression for the sky brightness and alleviating the effects of noise. Moreover, the Zernike expansions allow us to quantify in a straightforward way the average and zenithal sky brightness and its variation across the FOV, providing a convenient framework to study the time course of these magnitudes. We apply this framework to analyze the results of a one-year campaign of night sky brightness measurements made at the UCM observatory in Madrid.

The nature of the diffuse light near cities detected in nighttime satellite imagery.

Diffuse glow has been observed around brightly lit cities in nighttime satellite imagery since at least the first publication of large scale maps in the late 1990s. In the literature, this has often been assumed to be an error related to the sensor, and referred to as "blooming", presumably in relation to the effect that can occur when using a CCD to photograph a bright light source. Here we show that the effect seen on the DMSP/OLS, SNPP/VIIRS-DNB and ISS is not only instrumental, but in fact represents a real detection of light scattered by the atmosphere. Data from the Universidad Complutense Madrid sky brightness survey are compared to nighttime imagery from multiple sensors with differing spatial resolutions, and found to be strongly correlated. These results suggest that it should be possible for a future space-based imaging radiometer to monitor changes in the diffuse artificial skyglow of cities.

Prevention of atrial fibrillation following cardiac surgery: basis for a novel therapeutic strategy based on non-hypoxic myocardial preconditioning.

Atrial fibrillation is the most common complication of cardiac surgical procedures performed with cardiopulmonary bypass. It contributes to increased hospital length of stay and treatment costs. At present, preventive strategies offer only suboptimal benefits, despite improvements in anesthesia, surgical technique, and medical therapy. The pathogenesis of postoperative atrial fibrillation is considered to be multifactorial. However oxidative stress is a major contributory factor representing the unavoidable consequences of ischemia/reperfusion cycle occurring in this setting. Considerable evidence suggests the involvement of reactive oxygen species (ROS) in the pathogenic mechanism of this arrhythmia. Interestingly, the deleterious consequences of high ROS exposure, such as inflammation, cell death (apoptosis/necrosis) or fibrosis, may be abrogated by a myocardial preconditioning process caused by previous exposure to moderate ROS concentration known to trigger survival response mechanisms. The latter condition may be created by n-3 PUFA supplementation that could give rise to an adaptive response characterized by increased expression of myocardial antioxidant enzymes and/or anti-apoptotic pathways. In addition, a further reinforcement of myocardial antioxidant defenses could be obtained through vitamins C and E supplementation, an intervention also known to diminish enzymatic ROS production. Based on this paradigm, this review presents clinical and experimental evidence supporting the pathophysiological and molecular basis for a novel therapeutic approach aimed to diminish the incidence of postoperative atrial fibrillation through a non-hypoxic preconditioning plus a reinforcement of the antioxidant defense system in the myocardial tissue.

Evaluating Human Photoreceptoral Inputs from Night-Time Lights Using RGB Imaging Photometry.

Night-time lights interact with human physiology through different pathways starting at the retinal layers of the eye; from the signals provided by the rods; the S-, L- and M-cones; and the intrinsically photosensitive retinal ganglion cells (ipRGC). These individual photic channels combine in complex ways to modulate important physiological processes, among them the daily entrainment of the neural master oscillator that regulates circadian rhythms. Evaluating the relative excitation of each type of photoreceptor generally requires full knowledge of the spectral power distribution of the incoming light, information that is not easily available in many practical applications. One such instance is wide area sensing of public outdoor lighting; present-day radiometers onboard Earth-orbiting platforms with sufficient nighttime sensitivity are generally panchromatic and lack the required spectral discrimination capacity. In this paper, we show that RGB imagery acquired with off-the-shelf digital single-lens reflex cameras (DSLR) can be a useful tool to evaluate, with reasonable accuracy and high angular resolution, the photoreceptoral inputs associated with a wide range of lamp technologies. The method is based on linear regressions of these inputs against optimum combinations of the associated R, G, and B signals, built for a large set of artificial light sources by means of synthetic photometry. Given the widespread use of RGB imaging devices, this approach is expected to facilitate the monitoring of the physiological effects of light pollution, from ground and space alike, using standard imaging technology.

Estenosis tricuspídea de bioprótesis tratada mediante implante valvular percutáneo: una solución segura para un paciente inusual

Se comunica el caso de una mujer de 31 años quien había sido previamente sometida a reemplazo valvular aórtico, mitral y tricuspídeo en tres episodios quirúrgicos. Fue ingresada a nuestra sección de cardiologÍa con síntomas compatibles con insuficiencia cardiaca derecha. Se efectuó evaluación mediante ecocardiograma, sondeo cardíaco derecho/izquierdo, angioTAC cardíaco y cardio resonancia. Se diagnosticó una estenosis tricuspídea severa secundaria a disfunción de prótesis biológica. Debido a alto riesgo operatorio y riesgo de falla ventricular derecha post-operatorio, la paciente fue rechazada para reemplazo valvular quirúrgico. Se decidió efectuar reemplazo tricuspídeo procedimiento "valve in valve". Se logró efectuar de manera exitosa por abordeje venoso femoral, prótesis balón expansible. Se demostró corrección de la estenosis tricuspídea y la paciente evolucionó con remisión de los síntomas de falla cardíaca.

We report a 31-year-old woman who was previously subjected to aortic, mitral, and tricuspid valve replacement in three different surgical episodes. She was admitted to our cardiology section with acute right heart failure symptoms. She was studied by echocardiography, right/left heart catheterization, cardiac CT scan and cardiac magnetic resonance. A severe tricuspid stenosis due to biological prosthesis dysfunction was diagnosed. Due to high operative risk and risk of postoperative right ventricular failure, the patient was rejected for cardiovascular surgery. We decided on a percutaneous tricuspid "valve in valve replacement". The procedure was done successfully by venous femoral approach, with a balloon expandable prosthesis. Tricuspid stenosis was corrected and the patient evolved with remission of heart failure symptoms.

Non-hypoxic preconditioning of myocardium against postoperative atrial fibrillation: mechanism based on enhancement of the antioxidant defense system.

Oxidative stress underlies postoperative atrial fibrillation and electrophysiological remodelling associated with rapid atrial pacing. An increasing body of evidence indicates that the formation of reactive oxygen species (ROS) released following extracorporeal circulation are involved in the structural and functional myocardial impairment derived from the ischemia-reperfusion cycle. ROS behave as intracellular messengers mediating pathological processes, such as inflammation, apoptosis and necrosis, thereby participating in the pathophysiology of atrial fibrillation. Thus, increased superoxide (O(2)(.-)) production has been found in isolated atrial cardiomyocytes from patients with atrial fibrillation. Therefore, it seems reasonable to assume that the reinforcement of the antioxidant defense system should protect the heart against functional alterations in the cardiac rhythm. On this line, antioxidant enzyme induction through in vivo exposure to moderate concentration of ROS is associated with a reduction in the susceptibility of myocytes to ROS-induced injury. This response could be due to a prevailing effect of survival over apoptotic pathway. Previously, tissue preconditioning caused by prior exposure to an ischemia/reperfusion cycle has been successfully applied in experimental models and clinical settings associated with oxidative damage by ROS. However, such hypoxic preconditioning method is harmful to be applied to many clinical conditions associated with oxidative stress. In turn, experimental studies have revealed that non-enzymatic antioxidants produce a significant functional amelioration in cardiomyocytes subjected to an oxidative challenge. Moreover, clinical studies with patients scheduled for primary coronary artery bypass graft surgery had a reduced incidence of postoperative atrial fibrillation. We present the hypothesis of non-hypoxic preconditioning based on the association of pretreatment with n-3 polyunsaturated fatty acids followed by ascorbate plus alpha-tocoferol supplementation diminishes the incidence of postoperative atrial fibrillation in patients subjected to cardiac surgery with extracorporeal circulation.

Worldwide variations in artificial skyglow.

Despite constituting a widespread and significant environmental change, understanding of artificial nighttime skyglow is extremely limited. Until now, published monitoring studies have been local or regional in scope, and typically of short duration. In this first major international compilation of monitoring data we answer several key questions about skyglow properties. Skyglow is observed to vary over four orders of magnitude, a range hundreds of times larger than was the case before artificial light. Nearly all of the study sites were polluted by artificial light. A non-linear relationship is observed between the sky brightness on clear and overcast nights, with a change in behavior near the rural to urban landuse transition. Overcast skies ranged from a third darker to almost 18 times brighter than clear. Clear sky radiances estimated by the World Atlas of Artificial Night Sky Brightness were found to be overestimated by ~25%; our dataset will play an important role in the calibration and ground truthing of future skyglow models. Most of the brightly lit sites darkened as the night progressed, typically by ~5% per hour. The great variation in skyglow radiance observed from site-to-site and with changing meteorological conditions underlines the need for a long-term international monitoring program.

A randomized controlled trial to prevent post-operative atrial fibrillation by antioxidant reinforcement.

OBJECTIVES: This study was designed to assess whether the reinforcement of the antioxidant system, through n-3 fatty acids plus antioxidant vitamin supplementation, could reduce the incidence of post-operative atrial fibrillation. BACKGROUND: Therapy to prevent post-operative atrial fibrillation remains suboptimal. Although oxidative stress plays a key role in the pathogenesis of this arrhythmia, antioxidant reinforcement has produced controversial results. METHODS: A total of 203 patients scheduled for on-pump cardiac surgery were randomized to placebo or supplementation with n-3 polyunsaturated fatty acids (2 g/day) (eicosapentaenoic acid:docosahexaenoic acid ratio 1:2), vitamin C (1 g/day), and vitamin E (400 IU/day). The primary outcome was the occurrence of post-operative atrial fibrillation. Secondary outcomes were the biomarkers related to oxidative stress and inflammation. RESULTS: Post-operative atrial fibrillation occurred in 10 of 103 patients (9.7%) in the supplemented group versus 32 of 100 patients (32%) in the placebo group (p < 0.001). Early after surgery, placebo patients presented with increased levels of biomarkers of inflammation and oxidative stress, which were markedly attenuated by antioxidant supplementation. The activity of catalase, superoxide dismutase, and glutathione peroxidase in atrial tissue of the supplemented patients was 24.0%, 17.1%, and 19.7% higher than the respective placebo values (p < 0.05). The atrial tissue of patients who developed atrial fibrillation showed NADPH oxidase p47-phox subunit protein and mRNA expression 38.4% and 35.7% higher, respectively, than patients in sinus rhythm (p < 0.05). CONCLUSIONS: This safe, well-tolerated, and low-cost regimen, consisting of n-3 polyunsaturated fatty acids plus vitamins C and E supplementation, favorably affected post-operative atrial fibrillation, increased antioxidant potential, and attenuated oxidative stress and inflammation. (Prevention of Post-Operative Atrial Fibrillation: Pathophysiological Characterization of a Pharmacological Intervention Based on a Novel Model of Nonhypoxic Pre-Conditioning; ISRCTN45347268).

Antioxidant therapy reduces oxidative and inflammatory tissue damage in patients subjected to cardiac surgery with extracorporeal circulation.

Ischaemia reperfusion injury is a pathophysiological event that occurs after cardiac surgery with extracorporeal circulation. This clinical event has been associated with the induction of oxidative and inflammatory damage in atrial tissue. Here, we tested whether combined omega 3 polyunsaturated fatty acids (n-3 PUFA)-antioxidant vitamin protocol therapy reduces oxidative and inflammatory cardiac tissue damage. This trial assigned 95 either-sex patients to supplementation with n-3 PUFA (2 g/day), or matching placebo groups, 7 days before on-pump surgery. Antioxidant vitamins C (1 g/day) and E (400 IU/day) or placebo were added from 2 days before surgery until discharge. Blood and atrial tissue samples were obtained during the intervention. Reduced/oxidized glutathione (GSH/GSSG) ratio, malondialdehyde (MDA) and protein carbonylation were determined in atrial tissue. Leucocyte count and high-sensitivity C-reactive protein (hs-CRP) in blood plus nuclear factor (NF)-κappaB activation in atrial tissue served for inflammation assessment. Lipid peroxidation and protein carbonylation were 27.5 and 24% lower in supplemented patients (p < 0.01). GSH/GSSG ratio was 38.1% higher in supplemented patients compared with placebo (p < 0.01). Leucocyte count and serum hs-CRP levels were markedly lower throughout the protocol in supplemented patients (p < 0.01). Atrial tissue NF-κB DNA activation in supplemented patients was 22.5% lower than that in placebo patients (p < 0.05). The combined n-3 PUFA-antioxidant vitamin protocol therapy here proposed reduced the oxidative stress and inflammation biomarkers, in patients undergoing on-pump cardiac surgery.

Use of vitamins C and E as a prophylactic therapy to prevent postoperative atrial fibrillation.

Oxidative stress has been strongly involved in the underlying mechanism of atrial fibrillation, particularly in the arrhythmia occurring in patients undergoing cardiac surgery with extracorporeal circulation (postoperative atrial fibrillation). The ischemia/reperfusion injury thus occurring in the myocardial tissue contributes to the development of tissue remodeling, thought to be responsible for the functional heart impairment. Consequently, structural changes due to the cardiac tissue biomolecules attack by reactive oxygen and/or nitrogen species could account for functional changes in ion channels, transporters, membrane conductance, cytosolic transduction signals, and other events, all associated with the occurrence of arrhythmic consequences. The lack of success and significant side effects of anti-arrhythmic drugs have given rise to attempts aimed to develop alternative novel pharmacologic treatments. On this line, the biological properties of the antioxidant vitamins C and E suggest that they could decrease the vulnerability of the heart to the oxidative damage. Nevertheless, very few studies to assess their anti-arrhythmic effects have been reported in humans. The clinical and experimental evidence supporting the view that the pharmacological use of antioxidant vitamins could contribute to prevent postoperative atrial fibrillation is presented.

[Modification of phenylephrine induced contraction of human vessel rings by L-arginine and L-arginine methyl ester]. / Influencia del sistema nitridérgico en la respuesta contráctil a fenilefrina de anillos de vasos usados en revascularización coronaria.

BACKGROUND: Endothelial dysfunction is associated to a lower production of nitric oxide and a reduction of endothelium mediated vasodilation. AIM: To study the effects of pharmacological agents that modify nitric oxide synthetase (NOS) activity on tension changes induced by phenylephrine in rings of internal mammary and radial arteries and saphenous vein. MATERIAL AND METHODS: Vessel rings of 7 to 10 mm length were obtained from 32 patients subjected to coronary vascular surgery Fourteen samples of radial artery, 12 samples of internal mammary artery and 15 samples of saphenous vein were obtained. A maximal contraction was induced with KC1 and dose response curves for phenylephrine (FE) in the absence or presence of L-arginine and L-arginine methyl ester (L-NAME), were constructed. RESULTS: The tension induced by FE in internal mammary artery and saphenous vein reached a maximum, near 90% of 80 mM KCl-induced contraction, but in the radial artery, it reached a maximum of 63% (p <0.05). In all vessels, the dose response curves were significantly shifted to the right by L-arginine and to the left by L-NAME. CONCLUSIONS: Pre-incubation of human rings with L-ARG or L-NAME, changed the response to FE induced contraction, which may be related to different degrees of endothelial nitric oxide production or NO sensitivity. The basal NO production in radial artery seems to be larger than the other vessels.

Influencia del sistema nitridérgico en la respuesta contráctil a fenilefrina de anillos de vasos usados en revascularización coronaria / Modification of phenylephrine induced contraction of human vessel rings by L-arginine and L-arginine methyl ester

Background: Endothelial dysfunction is associated to a lower production of nitric oxide and a reduction of endothelium mediated vasodilation. Aim: To study the effects of pharmacological agents that modify nitric oxide synthetase (NOS) activity on tension changes induced by phenylephrine in rings of internal mammary and radial arteries and saphenous vein. Material and methods: Vessel rings of 7 to 10 mm length were obtained from 32 patients subjected to coronary vascular surgery Fourteen samples of radial artery, 12 samples of internal mammary artery and 15 samples of saphenous vein were obtained. A maximal contraction was induced with KC1 and dose response curves for phenylephrine (FE) in the absence or presence of L-arginine and L-arginine methyl ester (L-NAME), were constructed. Results: The tension induced by FE in internal mammary artery and saphenous vein reached a maximum, near 90 percent of 80 mM KCl-induced contraction, but in the radial artery, it reached a maximum of 63 percent (p <0.05). In all vessels, the dose response curves were significantly shifted to the right by L-arginine and to the íeft by L-NAME. Conclusions: Pre-incubation of human rings with L-ARG or L-NAME, changed the response to FE induced contraction, which may be related to different degrees of endothelial nitric oxide production or NO sensitivity. The basal NO production in radial artery seems to be larger than the other vessels.

Efecto agudo de las estatinas sobre la relajación vascular in vitro mediada por acetilcolina y nitroprusiato en vasos usados en la revascularización coronaria / Acute effect of statins on acetylcholine and nitroprusside induced vascular relaxation of vessels used for revascularization purposes

Antecedentes: Uno de los efectos pleiotrópicos de las estatinas es su capacidad de inducir relajación vascular tanto in Vitro como in Vivo cuando son administradas crónicamente, pero el efecto agudo en los vasos no ha sido estudiado en detalle. Objetivos: Evaluar los efectos agudos de las estatinas en la relajación vascular in vitro mediada por acetilcolina (ACh) y nitroprusiato en vasos usados en revascularización coronaria. Método: Se analizaron segmentos de vasos obtenidos de pacientes programados para cirugía de revascularización coronaria. Cada segmento de arteria radial, mamaria y vena safena fue dividido en dos, uno de ellos incubado durante dos horas con estatinas y el otro con solución buffer. Luego, se contrajo cada vaso con 80 mM de KCl y posteriormente con 10-4 M de noradrenalina seguido de administración de dosis acumulativas de ACh para inducir la relajación del vaso. Después de lavados repetidos, se contrae con la misma dosis de noradrenalina y se relaja con dosis creciente de nitroprusiato (NP). Resultados: La administración de KCl produjo una mayor contracción, aunque no significativa, en arterias radiales en relacióna los otros vasos, tanto en los incubados con estatinas como el grupo control. La noradrenalina produjo una mayor contracción no significativa en venas safenas; sin embargo no hubo diferencias entre los segmentos incubados con y sin estatinas. La vasodilatación por acetilcolina no se vio afectada por estatinas. La vasodilatación inducida por nitroprusiato no se modificó en presencia de estatinas en arterias radiales o mamaria. Sin embargo el tratamiento con estatina disminuyó significativamente la relajación inducida por nitroprusiato en la vena safena (p<0,05). Conclusión: Los resultados de este trabajo demuestran una respuesta diferencial de los vasos usados en revascularización coronaria frente al efecto agudo de estatina.

Obstrucción arterial poplítea secundaria a osteocondroma / Popliteal arterial obstruction secondary to osteochondroma

1. Se comunican dos casos de obliteración arterial poplítea secundaria a osteocondroma. 2. Se revisa la bibliografía y se comenta esta poco, frecuente causa de obstrucción arterial