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Background Photon-counting CT (PCCT) represents a recent advancement in CT, offering improved spatial resolution and spectral separability. By using multiple adjustable energy bins, PCCT enables K-edge imaging, allowing mixed contrast agent distinction. Deep-silicon is a new type of photon-counting detector with different characteristics compared with cadmium photon-counting detectors. Purpose To evaluate the performance of a prototype deep-Si PCCT scanner and compare it with that of a state-of-the-art dual-energy energy-integrating detector (EID) scanner in imaging coronary artery plaques enhanced with iodine and K-edge contrast agents. Materials and Methods A series of 10 three-dimensional-printed inserts (diameter, 3.5 mm) was prepared, and materials mimicking soft and calcified plaques were added to simulate stenosed coronary arteries. Inserts filled with an iodine- or gadolinium-based contrast agent (GBCA) were scanned. Virtual monoenergetic images (VMIs) and iodine maps were generated using two- and eight-energy bin data from EID CT and PCCT, respectively. Gadolinium maps were calculated for PCCT. The CT numbers of VMIs and iodine maps were compared. Spatial resolution and blooming artifacts were compared on the 70-keV VMIs in plaque-free and calcified coronary arteries. Results No evidence of a significant difference in the CT number of 70-keV images was found except in inserts containing GBCAs. In the absence of a GBCA, excellent (r > 0.99) agreement for iodine was found. PCCT could quantify the GBCA within 0.2 mg Gd/mL ± 0.8 accuracy of the ground truth, whereas EID CT failed to detect the GBCA. Lumen measurements were more accurate for PCCT than for EID CT, with mean errors of 167 versus 442 µm (P < .001) compared with the 3.5-mm ground truth. Conclusion Deep-Si PCCT demonstrated good accuracy in iodine quantification and could accurately decompose mixtures of two contrast agents. Its improved spatial resolution resulted in sharper images with blooming artifacts reduced by 50% compared with a state-of-the-art dual-energy EID CT scanner. © RSNA, 2024.
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Medios de Contraste , Fantasmas de Imagen , Fotones , Humanos , Tomografía Computarizada por Rayos X/métodos , Vasos Coronarios/diagnóstico por imagen , Silicio , Diseño de EquipoRESUMEN
Currently there are three test guidelines (TG) for acute oral toxicity studies of substances or mixtures from the Organisation for Economic Co-operation and Development (OECD). TG 423 and TG 425 use lethality as an endpoint, while TG 420 replaces death with 'evident toxicity', defined as clear signs that exposure to a higher dose would result in death. However, the perceived subjectivity of 'evident toxicity' may be preventing wider use of TG 420. To address this, the UK National Centre for the Replacement, Refinement and Reduction of Animals in Research (NC3Rs) and the European Partnership for Alternative Approaches to Animal Testing (EPAA) collaborated to provide recommendations on the recognition of 'evident toxicity'. Historical data from acute oral toxicity studies were analysed for clinical signs at the lower dose that could have predicted death at the higher dose. Several signs including ataxia, laboured respiration, and eyes partially closed, alone or in combination, are highly predictive. Others such as lethargy, decreased respiration, and loose faeces have lower but still appreciable positive predictive value (PPV). The data has been used to develop recommendations to promote use of TG 420 and thus reduce the suffering and numbers of animals used in acute oral toxicity studies.
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Diarrea , Organización para la Cooperación y el Desarrollo Económico , Animales , Pruebas de Toxicidad AgudaRESUMEN
BACKGROUND: Kidney failure is an established risk factor for tuberculosis (TB), but little is known about TB risk in people with chronic kidney disease (CKD) who have not initiated kidney replacement therapy (CKD without kidney failure). Our primary objective was to estimate the pooled relative risk of TB disease in people with CKD stages 3-5 without kidney failure compared with people without CKD. Our secondary objectives were to estimate the pooled relative risk of TB disease for all stages of CKD without kidney failure (stages 1-5) and by each CKD stage. METHODS: This review was prospectively registered (PROSPERO CRD42022342499). We systematically searched MEDLINE, Embase, and Cochrane databases for studies published between 1970 and 2022. We included original observational research estimating TB risk among people with CKD without kidney failure. Random-effects meta-analysis was performed to obtain the pooled relative risk. RESULTS: Of the 6915 unique articles identified, data from 5 studies were included. The estimated pooled risk of TB was 57% higher in people with CKD stages 3-5 than in people without CKD (adjusted hazard ratio: 1.57; 95% CI: 1.22-2.03; I2 = 88%). When stratified by CKD stage, the pooled rate of TB was highest in stages 4-5 (incidence rate ratio: 3.63; 95% CI: 2.25-5.86; I2 = 89%). CONCLUSIONS: People with CKD without kidney failure have an increased relative risk of TB. Further research and modeling are required to understand the risks, benefits, and CKD cutoffs for screening people for TB with CKD prior to kidney replacement therapy.
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Fallo Renal Crónico , Insuficiencia Renal Crónica , Tuberculosis , Humanos , Insuficiencia Renal Crónica/complicaciones , Insuficiencia Renal Crónica/epidemiología , Tuberculosis/complicaciones , Tuberculosis/epidemiología , Terapia de Reemplazo Renal , Factores de Riesgo , Fallo Renal Crónico/complicacionesRESUMEN
Scientists and managers rely on indicator taxa such as coral and macroalgal cover to evaluate the effects of human disturbance on coral reefs, often assuming a universally positive relationship between local human disturbance and macroalgae. Despite evidence that macroalgae respond to local stressors in diverse ways, there have been few efforts to evaluate relationships between specific macroalgae taxa and local human-driven disturbance. Using genus-level monitoring data from 1205 sites in the Indian and Pacific Oceans, we assess whether macroalgae percent cover correlates with local human disturbance while accounting for factors that could obscure or confound relationships. Assessing macroalgae at genus level revealed that no genera were positively correlated with all human disturbance metrics. Instead, we found relationships between the division or genera of algae and specific human disturbances that were not detectable when pooling taxa into a single functional category, which is common to many analyses. The convention to use percent cover of macroalgae as an indication of local human disturbance therefore likely obscures signatures of local anthropogenic threats to reefs. Our limited understanding of relationships between human disturbance, macroalgae taxa, and their responses to human disturbances impedes the ability to diagnose and respond appropriately to these threats.
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Antozoos , Algas Marinas , Animales , Humanos , Arrecifes de Coral , Ecosistema , Algas Marinas/fisiología , Antozoos/fisiología , Océano PacíficoRESUMEN
BACKGROUND: The Micra leadless pacemaker has demonstrated favorable outcomes in global trials, but its real-world performance and safety in a Japan-specific population is unknown.MethodsâandâResults: Micra Acute Performance (MAP) Japan enrolled 300 patients undergoing Micra VR leadless pacemaker implantation in 15 centers. The primary endpoint was the acute (30-day) major complication rate. The 30-day and 6-month major complication rates were compared to global Micra studies. All patients underwent successful implantation with an average follow-up of 7.23±2.83 months. Compared with previous Micra studies, Japanese patients were older, smaller, more frequently female, and had a higher pericardial effusion risk score. 11 acute major complications were reported in 10 patients for an acute complication rate of 3.33% (95% confidence interval: 1.61-6.04%), which was in line with global Micra trials. Pericardial effusion occurred in 4 patients (1.33%; 3 major, 1 minor). No procedure or device-related deaths occurred. Frailty significantly improved from baseline to follow-up as assessed by Japan Cardiovascular Health Study criteria. CONCLUSIONS: In a Japanese cohort, implantation of the Micra leadless pacemaker had a high success rate and low major complication rate. Despite the Japan cohort being older, smaller, and at higher risk, the safety and performance was in line with global Micra trials.
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Arritmias Cardíacas , Marcapaso Artificial , Femenino , Humanos , Pueblos del Este de Asia , Diseño de Equipo , Marcapaso Artificial/efectos adversos , Derrame Pericárdico/etiología , Resultado del Tratamiento , Masculino , Arritmias Cardíacas/terapiaRESUMEN
Marine fisheries in coastal ecosystems in many areas of the world have historically removed large-bodied individuals, potentially impairing ecosystem functioning and the long-term sustainability of fish populations. Reporting on size-based indicators that link to food-web structure can contribute to ecosystem-based management, but the application of these indicators over large (cross-ecosystem) geographical scales has been limited to either fisheries-dependent catch data or diver-based methods restricted to shallow waters (<20 m) that can misrepresent the abundance of large-bodied fished species. We obtained data on the body-size structure of 82 recreationally or commercially targeted marine demersal teleosts from 2904 deployments of baited remote underwater stereo-video (stereo-BRUV). Sampling was at up to 50 m depth and covered approximately 10,000 km of the continental shelf of Australia. Seascape relief, water depth, and human gravity (i.e., a proxy of human impacts) were the strongest predictors of the probability of occurrence of large fishes and the abundance of fishes above the minimum legal size of capture. No-take marine reserves had a positive effect on the abundance of fishes above legal size, although the effect varied across species groups. In contrast, sublegal fishes were best predicted by gradients in sea surface temperature (mean and variance). In areas of low human impact, large fishes were about three times more likely to be encountered and fishes of legal size were approximately five times more abundant. For conspicuous species groups with contrasting habitat, environmental, and biogeographic affinities, abundance of legal-size fishes typically declined as human impact increased. Our large-scale quantitative analyses highlight the combined importance of seascape complexity, regions with low human footprint, and no-take marine reserves in protecting large-bodied fishes across a broad range of species and ecosystem configurations.
Las pesquerías marinas de los ecosistemas costeros en muchas áreas del mundo históricamente han removido a individuos de gran tamaño, potencialmente perjudicando el funcionamiento ambiental y la sostenibilidad a largo plazo de las poblaciones de peces. Los reportes sobre los indicadores basados en el tamaño que se vinculan con la estructura de la red alimenticia pueden contribuir al manejo basado en el ecosistema, aunque la aplicación de estos indicadores a grandes (inter-ecosistemas) escalas geográficas ha estado limitada a datos de captura dependientes de las pesquerías o métodos basados en el buceo restringidos a aguas someras (<20 m), lo cual puede representar erróneamente la abundancia de peces de gran tamaño capturados para la pesca. Obtuvimos los datos de la estructura del tamaño corporal de 82 teleósteos marinos demersales focalizados por razones recreativas o comerciales tomados de 2,904 despliegues de video estéreo subacuático remoto con cebo (stereo-BRUV, en inglés). El muestreo se realizó hasta los 50 metros de profundidad y abarcó aproximadamente 10,000 km del talud continental de Australia. El relieve marino, la profundidad del agua y la gravedad humana (es decir, un indicador de los impactos humanos) fueron los pronosticadores más sólidos de la probabilidad de incidencia de los peces de gran tamaño y de la abundancia de peces por encima del tamaño legal mínimo de captura. Las reservas marinas de protección total tienen un efecto positivo sobre la abundancia de los peces que están por encima del tamaño legal, aunque el efecto varió según el grupo de especies. Como contraste, los peces de tamaño sublegal fueron pronosticados de mejor manera usando gradientes de la temperatura de la superficie marina (media y varianza). En las áreas con un impacto humano reducido, los peces de gran tamaño corporal tenían hasta tres veces mayor probabilidad de aparecer y los peces de tamaño legal eran aproximadamente cinco veces más abundantes. Para los grupos de especies conspicuas con afinidades contrastantes de hábitat, ambiente y biogeografía, la abundancia de peces de tamaño legal normalmente declinó conforme aumentó el impacto humano. Nuestros análisis cuantitativos a gran escala resaltan la importancia conjunta que tienen la complejidad marina, las regiones con una huella humana reducida y las reservas marinas de protección total para la protección de los peces de gran tamaño corporal en una extensa gama de especies y configuraciones ecosistémicas. Efectos de la Huella Humana y los Factores Biofísicos sobre la Estructura del Tamaño Corporal de Especies Marinas Capturadas para la Pesca.
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Conservación de los Recursos Naturales , Ecosistema , Animales , Australia , Tamaño Corporal , Explotaciones Pesqueras , Peces , HumanosRESUMEN
BACKGROUND: Chronic rhinosinusitis (CRS) in the setting of Aspirin Exacerbated Respiratory Disease (AERD) have high rate of treatment failure and disease recurrence. OBJECTIVE: Evaluate the long-term effect of zileuton on sinonasal outcomes in patients with AERD. METHODS: AERD patients were reviewed and divided into two cohorts, depending if they were treated with zileuton during their clinical course. Demographic data, 22-item sinonasal outcome test (SNOT-22), Lund-Kennedy (LK) endoscopy score, duration of treatment, and number of sinus surgeries performed were collected. RESULTS: 40 AERD patients were included, with follow-up duration up to 10 years (avg of 5.2 years). All patients were treated with topical saline and budesonide irrigations, intranasal steroid spray, and montelukast. 19 patients had uncontrolled sinus disease requiring multiple steroid tapers and were switched from montelukast to zileuton (cohort 1, 47.5%) at some point in their treatment. 21 patients (cohort 2, 52.5%) never needed zileuton. The average duration of treatment with zileuton was 6 years. Patients who required zileuton had a worse SNOT-22 (32.1 vs 19, p = 0.117), worse LK score (8.1 vs 7.5, p = 0.504), and higher average number of surgeries (1.9 vs 1.6, p = 0.343). The outcomes in the zileuton cohort trended toward improvement, however these did not reach statistical significance with an improved SNOT-22 from 32.1 to 27.4 (p = 0.617) and LK score from 7.9 to 6.2 (p = 0.092); The addition of zileuton significantly lowered the number of surgeries needed to an average of 0.5 (p < 0.0001). CONCLUSION: Zileuton may help decrease the number of sinus surgeries needed in AERD.
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Asma Inducida por Aspirina/tratamiento farmacológico , Hidroxiurea/análogos & derivados , Antagonistas de Leucotrieno/uso terapéutico , Rinitis/tratamiento farmacológico , Sinusitis/tratamiento farmacológico , Adulto , Anciano , Antiinflamatorios no Esteroideos/efectos adversos , Aspirina/efectos adversos , Asma Inducida por Aspirina/complicaciones , Enfermedad Crónica , Femenino , Humanos , Hidroxiurea/uso terapéutico , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Rinitis/inducido químicamente , Índice de Severidad de la Enfermedad , Sinusitis/inducido químicamente , Factores de Tiempo , Resultado del Tratamiento , Adulto JovenRESUMEN
More than a million cases of cutaneous squamous cell carcinoma are diagnosed in the USA each year, and its incidence is increasing. Most of these malignancies arise from premalignant lesions, providing an opportunity for intervention before malignant progression. We previously documented how cytoplasmic mislocalization of CDC25A in premalignant and malignant skin cancers confers resistance to apoptotic cell death via a mechanism that depends on its interaction with 14-3-3ε. From these data, we hypothesized that 14-3-3ε overexpression drives skin tumor development and progression, such that targeting 14-3-3ε may be a useful strategy for skin cancer treatment. Like CDC25A, 14-3-3ε was overexpressed and mislocalized to the cytoplasm of both benign and malignant human skin cancer. Skin-targeted deletion of the 14-3-3ε gene reduced skin tumor development by 75% and blocked malignant progression. 14-3-3ε suppressed apoptosis through activation of Akt, leading to inhibition of BCL2 associated agonist of cell death and upregulation of Survivin. Using virtual tetrapeptide libraries, we developed a novel peptide that specifically blocked 14-3-3ε heterodimerization and thereby prevented its interaction with CDC25A. The peptide reduced prosurvival signaling, killed skin cancer cells and reduced skin tumor growth in xenograft. Normal skin keratinocytes were unaffected by inhibition or deletion of 14-3-3ε. Thus, targeting of 14-3-3ε dimerization is a promising strategy for the treatment of premalignant skin lesions.
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Proteínas 14-3-3/antagonistas & inhibidores , Antineoplásicos/farmacología , Carcinoma de Células Escamosas/tratamiento farmacológico , Neoplasias Cutáneas/tratamiento farmacológico , Fosfatasas cdc25/metabolismo , Proteínas 14-3-3/genética , Proteínas 14-3-3/metabolismo , 9,10-Dimetil-1,2-benzantraceno/administración & dosificación , 9,10-Dimetil-1,2-benzantraceno/toxicidad , Animales , Antineoplásicos/uso terapéutico , Apoptosis/efectos de los fármacos , Carcinógenos/administración & dosificación , Carcinógenos/toxicidad , Carcinoma de Células Escamosas/patología , Línea Celular Tumoral , Citoplasma/efectos de los fármacos , Citoplasma/metabolismo , Femenino , Humanos , Queratinocitos , Masculino , Ratones , Ratones Noqueados , Neoplasias Experimentales/inducido químicamente , Neoplasias Experimentales/tratamiento farmacológico , Neoplasias Experimentales/patología , Multimerización de Proteína/efectos de los fármacos , Neoplasias Cutáneas/patología , Acetato de Tetradecanoilforbol/administración & dosificación , Acetato de Tetradecanoilforbol/análogos & derivados , Acetato de Tetradecanoilforbol/toxicidad , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Marine reserves are a key tool for the conservation of marine biodiversity, yet only ~2.5% of the world's oceans are protected. The integration of marine reserves into connected networks representing all habitats has been encouraged by international agreements, yet the benefits of this design has not been tested empirically. Australia has one of the largest systems of marine reserves, providing a rare opportunity to assess how connectivity influences conservation success. An Australia-wide dataset was collected using baited remote underwater video systems deployed across a depth range from 0 to 100 m to assess the effectiveness of marine reserves for protecting teleosts subject to commercial and recreational fishing. A meta-analytical comparison of 73 fished species within 91 marine reserves found that, on average, marine reserves had 28% greater abundance and 53% greater biomass of fished species compared to adjacent areas open to fishing. However, benefits of protection were not observed across all reserves (heterogeneity), so full subsets generalized additive modelling was used to consider factors that influence marine reserve effectiveness, including distance-based and ecological metrics of connectivity among reserves. Our results suggest that increased connectivity and depth improve the aforementioned marine reserve benefits and that these factors should be considered to optimize such benefits over time. We provide important guidance on factors to consider when implementing marine reserves for the purpose of increasing the abundance and size of fished species, given the expected increase in coverage globally. We show that marine reserves that are highly protected (no-take) and designed to optimize connectivity, size and depth range can provide an effective conservation strategy for fished species in temperate and tropical waters within an overarching marine biodiversity conservation framework.
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Biodiversidad , Conservación de los Recursos Naturales , Animales , Australia , Ecosistema , Explotaciones Pesqueras , Peces , Océanos y MaresRESUMEN
A systematic calibration approach is presented to correlate the digital output of an infrared camera and the scene temperature. Aided by the optoelectronic properties of the camera, as few as two experimental data points are needed to establish this correlation. This approach can readily include the effects of atmospheric transmission, scene emissivity, and different background subtractions. Hence, the temperature conversion in flight can be reliably obtained from laboratory calibration. The conversion function can also be used to identify the camera's thermal sensitivity and temperature resolution, which are important information in different space missions. In applying this calibration procedure to a laboratory camera and the compact thermal imager onboard the International Space Station, its validity is confirmed.
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Currently the only methods for non-genotoxic carcinogenic hazard assessment accepted by most regulatory authorities are lifetime carcinogenicity studies. However, these involve the use of large numbers of animals and the relevance of their predictive power and results has been scientifically challenged. With increased availability of innovative test methods and enhanced understanding of carcinogenic processes, it is believed that tumour formation can now be better predicted using mechanistic information. A workshop organised by the European Partnership on Alternative Approaches to Animal Testing brought together experts to discuss an alternative, mechanism-based approach for cancer risk assessment of agrochemicals. Data from a toolbox of test methods for detecting modes of action (MOAs) underlying non-genotoxic carcinogenicity are combined with information from subchronic toxicity studies in a weight-of-evidence approach to identify carcinogenic potential of a test substance. The workshop included interactive sessions to discuss the approach using case studies. These showed that fine-tuning is needed, to build confidence in the proposed approach, to ensure scientific correctness, and to address different regulatory needs. This novel approach was considered realistic, and its regulatory acceptance and implementation can be facilitated in the coming years through continued dialogue between all stakeholders and building confidence in alternative approaches.
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Agroquímicos/efectos adversos , Alternativas a las Pruebas en Animales , Pruebas de Carcinogenicidad , Transformación Celular Neoplásica/inducido químicamente , Neoplasias/inducido químicamente , Animales , Transformación Celular Neoplásica/genética , Transformación Celular Neoplásica/metabolismo , Transformación Celular Neoplásica/patología , Congresos como Asunto , Humanos , Pruebas de Mutagenicidad , Neoplasias/genética , Neoplasias/metabolismo , Neoplasias/patología , Medición de Riesgo , Pruebas de Toxicidad Subcrónica , ToxicocinéticaRESUMEN
Rural amenity migration, or the relocation for quality of life purposes as opposed to monetary enhancement, has been occurring for decades and has been particularly pronounced in the American West where the phenomenon peaked in the 1990s. Researchers have illustrated that some places are more attractive for migrants than others and that certain regional amenities hold considerable influence on where migrants relocate. Increased migration levels typically result in increased economic growth indicators, making amenity migration an attractive rural development strategy. But comprehensive econometric analysis focused on amenity migration in the American West has been lacking. To address this, we conducted an econometric analysis of attributes that influenced migration to rural Western counties from 1980 to 2010. Over 20 potential amenity supply categories were collated for 356 rural counties from 11 Western states, with a focus on public lands. Descriptive statistics and OLS regressions were estimated and interpreted. Traditional amenities of climate, water area, and regional access were highly associated with migration levels, while designated natural amenities of Wilderness and National Monuments were the most influential public lands for migration to rural Western counties. Farming and oil and gas dependency were negatively associated with migration levels. Increasing the amount of protected areas, and branding campaigns based on natural amenities, can be a critical development strategy for rural communities.
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Calidad de Vida , Población Rural , Agricultura , Humanos , Dinámica Poblacional , Planificación Social , Estados UnidosRESUMEN
p53 is an important tumor-suppressor protein that is mutated in more than 50% of cancers. Strategies for restoring normal p53 function are complicated by the oncogenic properties of mutant p53 and have not met with clinical success. To counteract mutant p53 activity, a variety of drugs with the potential to reconvert mutant p53 to an active wildtype form have been developed. However, these drugs are associated with various negative effects such as cellular toxicity, nonspecific binding to other proteins, and inability to induce a wildtype p53 response in cancer tissue. Here, we report on the effects of a curcumin analog, HO-3867, on p53 activity in cancer cells from different origins. We found that HO-3867 covalently binds to mutant p53, initiates a wildtype p53-like anticancer genetic response, is exclusively cytotoxic toward cancer cells, and exhibits high anticancer efficacy in tumor models. In conclusion, HO-3867 is a p53 mutant-reactivating drug with high clinical anticancer potential.
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Apoptosis/efectos de los fármacos , Curcumina/análogos & derivados , Proteínas Mutantes/genética , Mutación , Neoplasias/patología , Piperidonas/farmacología , Proteína p53 Supresora de Tumor/genética , Animales , Antineoplásicos/farmacología , Proliferación Celular/efectos de los fármacos , Curcumina/farmacología , Femenino , Humanos , Ratones , Ratones Desnudos , Proteínas Mutantes/metabolismo , Neoplasias/tratamiento farmacológico , Neoplasias/genética , Células Tumorales Cultivadas , Proteína p53 Supresora de Tumor/metabolismo , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
The tropicalization of temperate marine ecosystems can lead to increased herbivory rates, reducing the standing stock of seaweeds and potentially causing increases in detritus production. However, long-term studies analysing these processes associated with the persistence of tropical herbivores in temperate reefs are lacking. We assessed the seasonal variation in abundances, macrophyte consumption, feeding modes and defecation rates of the range-extending tropical rabbitfish Siganus fuscescens and the temperate silver drummer Kyphosus sydneyanus and herring cale Olisthops cyanomelas on tropicalized reefs of Western Australia. Rabbitfish overwintered in temperate reefs, consumed more kelp and other macrophytes in all feeding modes, and defecated more during both summer and winter than the temperate herbivores. Herbivory and defecation increased with rabbitfish abundance, but this was dependent on temperature, with higher rates attained by big schools during summer and lower rates in winter. Still, rabbitfish surpassed temperate herbivores, leading to a fivefold acceleration in the transformation of macrophyte standing stock to detritus, a function usually attributed to sea urchins in kelp forests. Our results suggest that further warming and tropicalization will not only increase primary consumption and affect the habitat structure of temperate reefs but also increase detritus production, with the potential to modify energy pathways.
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Arrecifes de Coral , Defecación , Conducta Alimentaria , Peces/fisiología , Cadena Alimentaria , Calentamiento Global , Animales , Cambio Climático , Perciformes/fisiología , Dinámica Poblacional , Estaciones del Año , Australia OccidentalRESUMEN
Non-melanoma skin cancer frequently results from chronic exposure to ultraviolet (UV) irradiation. UV-induced DNA damage activates cell cycle arrest checkpoints through degradation of the cyclin-dependent kinase activators, the cell division cycle 25 (CDC25) phosphatases. We previously reported increased CDC25A in nonmelanoma skin cancer, but CDC25B and CDC25C had not been previously examined. Consequently, we hypothesized that increased expression of CDC25B and CDC25C increases tumor cell proliferation and skin tumor growth. We found that CDC25B and CDC25C were increased in mouse and human skin cancers. CDC25B was primarily cytoplasmic in skin and skin tumors and was significantly increased in the squamous cell carcinoma (SCC), while CDC25C was mostly nuclear in the skin, with an increased cytoplasmic signal in the premalignant and malignant tumors. Surprisingly, forced expression of CDC25B or CDC25C in cultured SCC cells did not affect proliferation, but instead suppressed apoptosis, while CDC25C silencing increased apoptosis without impacting proliferation. Targeting CDC25C to the nucleus via mutation of its nuclear export sequence, however, increased proliferation in SCC cells. Overexpression of CDC25C in the nuclear compartment did not hinder the ability of CDC25C to suppress apoptosis, neither did mutation of sites necessary for its interaction with 14-3-3 proteins. Analysis of apoptotic signaling pathways revealed that CDC25C increased activating phosphorylation of Akt on Ser473 , increased inhibitory phosphorylation of proapoptotic BAD on Ser136 , and increased the survival protein Survivin. Silencing of CDC25C significantly reduced Survivin levels. Taken together, these data suggest that increased expression of CDC25B or CDC25C are mechanisms by which skin cancers evade apoptotic cell death.
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Muerte Celular/genética , Neoplasias Cutáneas/genética , Fosfatasas cdc25/genética , Animales , Apoptosis/genética , Carcinoma de Células Escamosas/genética , Ciclo Celular/genética , Línea Celular Tumoral , Núcleo Celular/genética , Proliferación Celular/genética , Citoplasma/genética , Daño del ADN/genética , Humanos , Ratones , Ratones Transgénicos/genética , Fosforilación/genética , Transducción de Señal/genéticaRESUMEN
Aberrant subcellular localization of signaling proteins can provide cancer cells with advantages such as resistance to apoptotic cell death, increased invasiveness and more rapid proliferation. Nuclear to cytoplasmic shifts in tumor-promoting proteins can lead to worse patient outcomes, providing opportunities to target cancer-specific processes. Herein, we review the significance of dysregulated protein localization with a focus on skin cancer. Altered localization of signaling proteins controlling cell cycle progression or cell death is a common feature of cancer. In some instances, aberrant subcellular localization results in an acquired prosurvival function. Taking advantage of this knowledge reveals novel targets useful in the development of cancer therapeutics.
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Transducción de Señal/fisiología , Neoplasias Cutáneas/metabolismo , Animales , Apoptosis/fisiología , Ciclo Celular/fisiología , Núcleo Celular/metabolismo , Proliferación Celular/fisiología , Citoplasma/metabolismo , HumanosRESUMEN
Monitoring the effects of water availability on vegetation globally using satellites is important for applications such as drought early warning, precision agriculture, and food security as well as for more broadly understanding relationships between water and carbon cycles. In this global study, we examine how quickly several satellite-based indicators, assumed to have relationships with water availability, respond, on timescales of days to weeks, in comparison with variations in root-zone soil moisture (RZM) that extends to about 1 m depth. The satellite indicators considered are the normalized difference vegetation and infrared indices (NDVI and NDII, respectively) derived from reflectances obtained with moderately wide (20-40 nm) spectral bands in the visible and near-infrared (NIR) and evapotranspiration (ET) estimated from thermal infrared observations and normalized by a reference ET. NDVI is primarily sensitive to chlorophyll contributions and vegetation structure while NDII may contain additional information on water content in leaves and canopy. ET includes both the loss of root zone soil water through transpiration (modulated by stomatal conductance) as well as evaporation from bare soil. We find that variations of these satellite-based drought indicators on time scales of days to weeks have significant correlations with those of RZM in the same water-limited geographical locations that are dominated by grasslands, shrublands, and savannas whose root systems are generally contained within the 1 m RZM layer. Normalized ET interannual variations show generally a faster response to water deficits and enhancements as compared with those of NDVI and NDII, particularly in sparsely vegetated regions.
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An accurate temporal and spatial characterization of errors is required for the efficient processing, evaluation, and assimilation of remotely-sensed surface soil moisture retrievals. However, empirical evidence exists that passive microwave soil moisture retrievals are prone to periodic artifacts which may complicate their application in data assimilation systems (which commonly treat observational errors as being temporally white). In this paper, the link between such temporally-periodic errors and spatial land surface heterogeneity is examined. Both the synthetic experiment and site-specified cases reveal that, when combined with strong spatial heterogeneity, temporal periodicity in satellite sampling patterns (associated with exact repeat intervals of the polar-orbiting satellites) can lead to spurious high frequency spectral peaks in soil moisture retrievals. In addition, the global distribution of the most prominent and consistent 8-day spectral peak in the Advanced Microwave Scanning Radiometer - Earth Observing System soil moisture retrievals is revealed via a peak detection method. Three spatial heterogeneity indicators - based on microwave brightness temperature, land cover types, and long-term averaged vegetation index - are proposed to characterize the degree to which the variability of land surface is capable of inducing periodic error into satellite-based soil moisture retrievals. Regions demonstrating 8-day periodic errors are generally consistent with those exhibiting relatively higher heterogeneity indicators. This implies a causal relationship between spatial land surface heterogeneity and temporal periodic error in remotely-sensed surface soil moisture retrievals.
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Acute inhalation studies are conducted in animals as part of chemical hazard identification and for classification and labelling. Current methods employ death as an endpoint (Organisation for Economic Co-operation and Development (OECD) test guideline (TG) 403 and TG436) while the recently approved fixed concentration procedure (FCP) (OECD TG433) uses fewer animals and replaces lethality as an endpoint with evident toxicity. Evident toxicity is the presence of clinical signs that predict that exposure to the next highest concentration will cause severe toxicity or death in most animals. Approval of TG433 was the result of an international initiative, led by the National Centre for the Replacement, Refinement & Reduction of Animals in Research (NC3Rs), which collected data from six laboratories on clinical signs recorded for inhalation studies on 172 substances. This paper summarises previously published data and describes the additional analyses of the dataset that were essential for approval of the TG.
Asunto(s)
Pruebas de Toxicidad Aguda/métodos , Administración por Inhalación , Alternativas al Uso de Animales/métodos , Animales , Femenino , MasculinoRESUMEN
As a key variable in the climate system, soil moisture (SM) plays a central role in the earth's terrestrial water, energy, and biogeochemical cycles through its coupling with surface latent heat flux (LH). Despite the need to accurately represent SM/LH coupling in earth system models, we currently lack quantitative, observation-based, and unbiased estimates of its strength. Here, we utilize the triple collocation (TC) approach introduced in Crow et al. (2015) to SM and LH products obtained from multiple satellite remote sensing platforms and land surface models (LSMs) to obtain unbiased global maps of SM/LH coupling strength. Results demonstrate that, relative to coupling strength estimates acquired directly from remote sensing-based datasets, the application of TC generally enhances estimates of warm-season SM/LH coupling, especially in the western United States, the Sahel, Central Asia, and Australia. However, relative to triple collocation estimates, LSMs (still) over-predict SM/LH coupling strength along transitional climate regimes between wet and dry climates, such as the central Great Plains of North America, India, and coastal Australia. Specific climate zones with biased relations in LSMs are identified to geographically focus the re-examination of LSM parameterizations. TC-based coupling strength estimates are robust to our choice of LSM contributing SM and LH products to the TC analysis. Given their robustness, TC-based coupling strength estimates can serve as an objective benchmark for investigating model predicted SM/LH coupling.