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PubMed Central (PMC3 - NLM DTD) (2,719,667 recursos)
Archive of life sciences journal literature at the U.S. National Institutes of Health (NIH), developed and managed by NIH's National Center for Biotechnology Information (NCBI) in the National Library of Medicine (NLM).

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Mostrando recursos 1 - 20 de 388,078

1. Interpretive monitoring in the caudate nucleus - Yanike, Marianna; Ferrera, Vincent P
In a dynamic environment an organism has to constantly adjust ongoing behavior to adapt to a given context. This process requires continuous monitoring of ongoing behavior to provide its meaningful interpretation. The caudate nucleus is known to have a role in behavioral monitoring, but the nature of these signals during dynamic behavior is still unclear. We recorded neuronal activity in the caudate nucleus in monkeys during categorization behavior that changed rapidly across contexts. We found that neuronal activity maintained representation of the identity and context of a recently categorized stimulus, as well as interpreted the behavioral meaningfulness of the maintained...

2. Phenotype-based cell-specific metabolic modeling reveals metabolic liabilities of cancer - Yizhak, Keren; Gaude, Edoardo; Le Dévédec, Sylvia; Waldman, Yedael Y; Stein, Gideon Y; van de Water, Bob; Frezza, Christian; Ruppin, Eytan
Utilizing molecular data to derive functional physiological models tailored for specific cancer cells can facilitate the use of individually tailored therapies. To this end we present an approach termed PRIME for generating cell-specific genome-scale metabolic models (GSMMs) based on molecular and phenotypic data. We build >280 models of normal and cancer cell-lines that successfully predict metabolic phenotypes in an individual manner. We utilize this set of cell-specific models to predict drug targets that selectively inhibit cancerous but not normal cell proliferation. The top predicted target, MLYCD, is experimentally validated and the metabolic effects of MLYCD depletion investigated. Furthermore, we tested...

3. Cranial biomechanics underpins high sauropod diversity in resource-poor environments - Button, David J.; Rayfield, Emily J.; Barrett, Paul M.
High megaherbivore species richness is documented in both fossil and contemporary ecosystems despite their high individual energy requirements. An extreme example of this is the Late Jurassic Morrison Formation, which was dominated by sauropod dinosaurs, the largest known terrestrial vertebrates. High sauropod diversity within the resource-limited Morrison is paradoxical, but might be explicable through sophisticated resource partitioning. This hypothesis was tested through finite-element analysis of the crania of the Morrison taxa Camarasaurus and Diplodocus. Results demonstrate divergent specialization, with Camarasaurus capable of exerting and accommodating greater bite forces than Diplodocus, permitting consumption of harder food items. Analysis of craniodental biomechanical...

4. Listening to the environment: hearing differences from an epigenetic effect in solitarious and gregarious locusts - Gordon, Shira D.; Jackson, Joseph C.; Rogers, Stephen M.; Windmill, James F. C.
Locusts display a striking form of phenotypic plasticity, developing into either a lone-living solitarious phase or a swarming gregarious phase depending on population density. The two phases differ extensively in appearance, behaviour and physiology. We found that solitarious and gregarious locusts have clear differences in their hearing, both in their tympanal and neuronal responses. We identified significant differences in the shape of the tympana that may be responsible for the variations in hearing between locust phases. We measured the nanometre mechanical responses of the ear's tympanal membrane to sound, finding that solitarious animals exhibit greater displacement. Finally, neural experiments signified...

5. Evolution of cultural traits occurs at similar relative rates in different world regions - Currie, Thomas E.; Mace, Ruth
A fundamental issue in understanding human diversity is whether or not there are regular patterns and processes involved in cultural change. Theoretical and mathematical models of cultural evolution have been developed and are increasingly being used and assessed in empirical analyses. Here, we test the hypothesis that the rates of change of features of human socio-cultural organization are governed by general rules. One prediction of this hypothesis is that different cultural traits will tend to evolve at similar relative rates in different world regions, despite the unique historical backgrounds of groups inhabiting these regions. We used phylogenetic comparative methods and...

6. Aquatic polymers can drive pathogen transmission in coastal ecosystems - Shapiro, Karen; Krusor, Colin; Mazzillo, Fernanda F. M.; Conrad, Patricia A.; Largier, John L.; Mazet, Jonna A. K.; Silver, Mary W.
Gelatinous polymers including extracellular polymeric substances (EPSs) are fundamental to biophysical processes in aquatic habitats, including mediating aggregation processes and functioning as the matrix of biofilms. Yet insight into the impact of these sticky molecules on the environmental transmission of pathogens in the ocean is limited. We used the zoonotic parasite Toxoplasma gondii as a model to evaluate polymer-mediated mechanisms that promote transmission of terrestrially derived pathogens to marine fauna and humans. We show that transparent exopolymer particles, a particulate form of EPS, enhance T. gondii association with marine aggregates, material consumed by organisms otherwise unable to access micrometre-sized particles....

7. Microbial community dynamics in the forefield of glaciers - Bradley, James A.; Singarayer, Joy S.; Anesio, Alexandre M.
Retreating ice fronts (as a result of a warming climate) expose large expanses of deglaciated forefield, which become colonized by microbes and plants. There has been increasing interest in characterizing the biogeochemical development of these ecosystems using a chronosequence approach. Prior to the establishment of plants, microbes use autochthonously produced and allochthonously delivered nutrients for growth. The microbial community composition is largely made up of heterotrophic microbes (both bacteria and fungi), autotrophic microbes and nitrogen-fixing diazotrophs. Microbial activity is thought to be responsible for the initial build-up of labile nutrient pools, facilitating the growth of higher order plant life in...

8. The movement ecology of seagrasses - McMahon, Kathryn; van Dijk, Kor-jent; Ruiz-Montoya, Leonardo; Kendrick, Gary A.; Krauss, Siegfried L.; Waycott, Michelle; Verduin, Jennifer; Lowe, Ryan; Statton, John; Brown, Eloise; Duarte, Carlos
A movement ecology framework is applied to enhance our understanding of the causes, mechanisms and consequences of movement in seagrasses: marine, clonal, flowering plants. Four life-history stages of seagrasses can move: pollen, sexual propagules, vegetative fragments and the spread of individuals through clonal growth. Movement occurs on the water surface, in the water column, on or in the sediment, via animal vectors and through spreading clones. A capacity for long-distance dispersal and demographic connectivity over multiple timeframes is the novel feature of the movement ecology of seagrasses with significant evolutionary and ecological consequences. The space–time movement footprint of different life-history...

9. Copper is required for oncogenic BRAF signaling and tumorigenesis - Brady, Donita C.; Crowe, Matthew S.; Turski, Michelle L.; Hobbs, G. Aaron; Yao, Xiaojie; Chaikuad, Apirat; Knapp, Stefan; Xiao, Kunhong; Campbell, Sharon L.; Thiele, Dennis J.; Counter, Christopher M.
The BRAF kinase is mutated, typically V600E, to induce an active oncogenic state in a large fraction of melanoma, thyroid, hairy cell leukemia, and to a lesser extent, a wide spectrum of other cancers1,2. BRAFV600E phosphorylates and activates the kinases MEK1 and MEK2, which in turn phosphorylate and activate the kinases ERK1 and ERK2, stimulating the MAPK pathway to promote cancer3. Targeting MEK1/2 is proving to be an important therapeutic strategy, as a MEK1/2 inhibitor provides a survival advantage in metastatic melanoma4, which is increased when co-administered with a BRAFV600E inhibitor5. In this regard, we previously found that copper (Cu)...

10. Year in review 2012: Critical Care - out-of-hospital cardiac arrest and trauma - Goldberg, Scott A; Leatham, Auna; Pepe, Paul E
In 2012 Critical Care published many articles pertaining to the resuscitation of out-of-hospital cardiac arrest and trauma. In this review, we summarize several of these articles, including those regarding advances in resuscitation techniques and methods. We examine articles pertaining to prehospital endotracheal intubation, the use of specialized devices for cardiopulmonary resuscitation and policies regarding transport destinations for both cardiac arrest and trauma patients. Articles on the predictors of outcome in both pediatric and adult populations are evaluated, including articles on the effects of obesity on survival from hemorrhage and pediatric outcomes from traumatic cardiac arrest. The effects of the type...

11. Year in review 2012: Critical Care - cardiology - De Backer, Daniel
In this review I discuss key research papers in cardiology and intensive care published in Critical Care during 2012 with related studies published in other journals quoted whenever appropriate. These studies are grouped into the following categories: cardiovascular therapies, mechanical therapies, pathophysiologic mechanisms, hemodynamic monitoring, ultrasound in respiratory failure, microcirculation, and miscellaneous.

12. Year in review 2012: Critical Care -management - Duggal, Abhijit; Rubenfeld, Gordon
Outcomes research plays a key role in defining the effects of medical care in critical care. Last year Critical Care published a number of papers that evaluated patient-centered and policy-relevant outcomes. We present this review article focusing on key reported outcomes associated with severe community-acquired pneumonia, mortality associated with decisions regarding triage to the ICU, and both short-term and long-term mortality associated with ICU admissions. We further analyze the literature, assessing outcomes such as quality of life and the psychological burden associated with critical care. We also reviewed processes of care, and studies looking at cost analysis of treatment associated...

13. Year in review 2012: Critical Care - respiratory infections - Nair, Girish B; Niederman, Michael S
Over the last two decades, considerable progress has been made in the understanding of disease mechanisms and infection control strategies related to infections, particularly pneumonia, in critically ill patients. Patient-centered and preventative strategies assume paramount importance in this era of limited health-care resources, in which effective targeted therapy is required to achieve the best outcomes. Risk stratification using severity scores and inflammatory biomarkers is a promising strategy for identifying sick patients early during their hospital stay. The emergence of multidrug-resistant pathogens is becoming a major hurdle in intensive care units. Cooperation, education, and interaction between multiple disciplines in the intensive...

14. Year in review 2012: Critical Care - respirology - Goligher, Ewan C; Fan, Eddy; Slutsky, Arthur S
Acute respiratory failure is a dominant feature of critical illness. In this review, we discuss 17 studies published last year in Critical Care. The discussion focuses on articles on several topics: respiratory monitoring, acute respiratory distress syndrome, noninvasive ventilation, airway management, secretion management and weaning.

15. Year in review 2012: Critical Care - nephrology - Ricci, Zaccaria; Ronco, Claudio
We summarize original research in the field of critical care nephrology accepted or published in 2012 in Critical Care and, when considered relevant or directly linked to this research, in other journals. Three main topics have been identified for a rapid overview: acute kidney injury, detailed in some pathogenetic and epidemiological aspects; fluid overload as a predictor of mortality both in acute kidney injury and renal replacement therapy (RRT) patients; and RRT, evaluating some features of citrate anticoagulation and describing the effects of RRT modalities or timing on survival.

16. The non-coding genome: a universe in expansion for fine-tuning the coding world - Luco, Reini F
A report on the EMBO/EMBL Symposium on The Non-Coding Genome, held in Heidelberg, Germany, 9-12 October, 2013.

17. Intra-tumor heterogeneity: lessons from microbial evolution and clinical implications - de Bruin, Elza C; Taylor, Tiffany B; Swanton, Charles
Multiple subclonal populations of tumor cells can coexist within the same tumor. This intra-tumor heterogeneity will have clinical implications and it is therefore important to identify factors that drive or suppress such heterogeneous tumor progression. Evolutionary biology can provide important insights into this process. In particular, experimental evolution studies of microbial populations, which exist as clonal populations that can diversify into multiple subclones, have revealed important evolutionary processes driving heterogeneity within a population. There are transferrable lessons that can be learnt from these studies that will help us to understand the process of intra-tumor heterogeneity in the clinical setting. In...

18. The impact of Cochrane Systematic Reviews: a mixed method evaluation of outputs from Cochrane Review Groups supported by the UK National Institute for Health Research - Bunn, Frances; Trivedi, Daksha; Alderson, Phil; Hamilton, Laura; Martin, Alice; Iliffe, Steve

19. MiR-133b regulates bladder cancer cell proliferation and apoptosis by targeting Bcl-w and Akt1 - Chen, Xiao-nan; Wang, Ke-feng; Xu, Zhen-qun; Li, Shi-jie; Liu, Qiang; Fu, Dong-hui; Wang, Xia; Wu, Bin

20. Leiomyoma – a rare benign tumor of the female urethra: a case report - de Lima Junior, Mário Maciel; Sampaio, Cleyton Barbosa; Ticianeli, José Geraldo; de Lima, Mário Maciel; Granja, Fabiana

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