964 resultados para Current generation
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The aim of this work was to design a novel strategy to detect new targets for anticancer treatments. The rationale was to build Biological Association Networks from differentially expressed genes in drug-resistant cells to identify important nodes within the Networks. These nodes may represent putative targets to attack in cancer therapy, as a way to destabilize the gene network developed by the resistant cells to escape from the drug pressure. As a model we used cells resistant to methotrexate (MTX), an inhibitor of DHFR. Selected node-genes were analyzed at the transcriptional level and from a genotypic point of view. In colon cancer cells, DHFR, the AKR1 family, PKC¿, S100A4, DKK1, and CAV1 were overexpressed while E-cadherin was lost. In breast cancer cells, the UGT1A family was overexpressed, whereas EEF1A1 was overexpressed in pancreatic cells. Interference RNAs directed against these targets sensitized cells towards MTX.
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Inducible defenses, which provide enhanced resistance after initial attack, are nearly universal in plants. This defense signaling cascade is mediated by the synthesis, movement, and perception of jasmonic acid and related plant metabolites. To characterize the long-term persistence of plant immunity, we challenged Arabidopsis (Arabidopsis thaliana) and tomato (Solanum lycopersicum) with caterpillar herbivory, application of methyl jasmonate, or mechanical damage during vegetative growth and assessed plant resistance in subsequent generations. Here, we show that induced resistance was associated with transgenerational priming of jasmonic acid-dependent defense responses in both species, caused caterpillars to grow up to 50% smaller than on control plants, and persisted for two generations in Arabidopsis. Arabidopsis mutants that are deficient in jasmonate perception (coronatine insensitive1) or in the biogenesis of small interfering RNA (dicer-like2 dicer-like3 dicer-like4 and nuclear RNA polymerase d2a nuclear RNA polymerase d2b) do not exhibit inherited resistance. The observation of inherited resistance in both the Brassicaceae and Solanaceae suggests that this trait may be more widely distributed in plants. Epigenetic resistance to herbivory thus represents a phenotypically plastic mechanism for enhanced defense across generations.
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A large variety of cancer vaccines have undergone extensive testing in early-phase clinical trials. A limited number have also been tested in randomized phase II clinical trials. Encouraging trends toward increased survival in the vaccine arms have been recently observed for 2 vaccine candidates in patients with non-small-cell lung cancer. These have provided the impetus for the initiation of phase III trials in large groups of patients with lung cancer. These vaccines target 2 antigens widely expressed in lung carcinomas: melanoma-associated antigen 3, a cancer testis antigen; and mucin 1, an antigen overexpressed in a largely deglycosylated form in advanced tumors. Therapeutic cancer vaccines aim at inducing strong CD8 and CD4 T-cell responses. The majority of vaccines recently tested in phase I clinical trials show efficacy in terms of induction of specific tumor antigen immunity. However, clinical efficacy remains to be determined but appears limited. Efforts are thus aimed at understanding the basis for this apparent lack of effect on tumors. Two major factors are involved. On one hand, current vaccines are suboptimal. Strong adjuvant agents and appropriate tumor antigens are needed. Moreover, dose, route, and schedule also need optimization. On the other hand, it is now clear that large tumors often present a tolerogenic microenvironment that hampers effective antitumor immunity. The partial understanding of the molecular pathways leading to functional inactivation of T cells at tumor sites has provided new targets for intervention. In this regard, blockade of cytotoxic T-lymphocyte antigen-4 and programmed death-1 with humanized monoclonal antibodies has reached the clinical testing stage. In the future, more potent cancer vaccines will benefit from intense research in antigen discovery and adjuvant agents. Furthermore, it is likely that vaccines need to be combined with compounds that reverse major tolerogenic pathways that are constitutively active at the tumor site. Developing these combined approaches to vaccination in cancer promises new, exciting findings and, at the same time, poses important challenges to academic research institutions and the pharmaceutical industry.
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In the past 5 years "Next-generation" Sequencing (NGS) technologies have transformed genomics by delivering fast, inexpensive and accurate genomeinformation changing the way we think about scientific approaches in basic,applied and clinical research. The inexpensive production of large volumes ofsequence data is the main advantage over the automated Sanger method,making this new technology useful for many applications. In this chapter, a brieftechnical review of NGS technologies is given, along with the keys to NGSsuccess and a broad range of applications for NGS technologies.
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A general understanding of interactions between DNA andoppositely charged compounds forms the basis for developing novelDNA-based materials, including gel particles. The association strength,which is altered by varying the chemical structure of the cationiccosolute, determines the spatial homogeneity of the gelation process,creating DNA reservoir devices and DNA matrix devices that can bedesigned to release either single- (ssDNA) or double-stranded(dsDNA) DNA. This paper reviews the preparation of DNA gelparticles using surfactants, proteins and polysaccharides. Particlemorphology, swelling/dissolution behaviour, degree of DNAentrapment and DNA release responses as a function of the nature ofthe cationic agent used are discussed. Current directions in thehaemocompatible and cytotoxic characterization of these DNA gelparticles have been also included.
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BACKGROUND: Elderly patients are emerging as a population at high risk for infective endocarditis (IE). However, adequately sized prospective studies on the features of IE in elderly patients are lacking. METHODS: In this multinational, prospective, observational cohort study within the International Collaboration on Endocarditis, 2759 consecutive patients were enrolled from June 15, 2000, to December 1, 2005; 1056 patients with IE 65 years or older were compared with 1703 patients younger than 65 years. Risk factors, predisposing conditions, origin, clinical features, course, and outcome of IE were comprehensively analyzed. RESULTS: Elderly patients reported more frequently a hospitalization or an invasive procedure before IE onset. Diabetes mellitus and genitourinary and gastrointestinal cancer were the major predisposing conditions. Blood culture yield was higher among elderly patients with IE. The leading causative organism was Staphylococcus aureus, with a higher rate of methicillin resistance. Streptococcus bovis and enterococci were also significantly more prevalent. The clinical presentation of elderly patients with IE was remarkable for lower rates of embolism, immune-mediated phenomena, or septic complications. At both echocardiography and surgery, fewer vegetations and more abscesses were found, and the gain in the diagnostic yield of transesophageal echocardiography was significantly larger. Significantly fewer elderly patients underwent cardiac surgery (38.9% vs 53.5%; P < .001). Elderly patients with IE showed a higher rate of in-hospital death (24.9% vs 12.8%; P < .001), and age older than 65 years was an independent predictor of mortality. CONCLUSIONS: In this large prospective study, increasing age emerges as a major determinant of the clinical characteristics of IE. Lower rates of surgical treatment and high mortality are the most prominent features of elderly patients with IE. Efforts should be made to prevent health care-associated acquisition and improve outcomes in this major subgroup of patients with IE.
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Allergen-specific immunotherapy is the only immunomodulatory and etiological therapy of allergy and asthma. Conventional specific immunotherapy (SIT) with whole-allergen extract is antigen specific, effective on multiple organs, efficient on asthma in defined conditions, provides long-lasting protection and is cost effective. Moreover, SIT is able to prevent the course of rhinitis to asthma. SIT has its drawbacks: the long duration of treatment, the unsatisfactory standardization of allergen extracts and a questionable safety level. Novel approaches are aimed at drastically reducing adverse anaphylactic events, shortening the duration of therapy and improving its efficacy. Novel promising approaches have based their formulation on a limited set of recombinant allergens or chimeric molecules as well as on hypoallergenic allergen fragments or peptides. The simultaneous use of adjuvants with immunomodulatory properties may contribute to improve both the safety and efficacy of allergen-SIT of allergy and asthma.
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Community-level patterns of functional traits relate to community assembly and ecosystem functioning. By modelling the changes of different indices describing such patterns - trait means, extremes and diversity in communities - as a function of abiotic gradients, we could understand their drivers and build projections of the impact of global change on the functional components of biodiversity. We used five plant functional traits (vegetative height, specific leaf area, leaf dry matter content, leaf nitrogen content and seed mass) and non-woody vegetation plots to model several indices depicting community-level patterns of functional traits from a set of abiotic environmental variables (topographic, climatic and edaphic) over contrasting environmental conditions in a mountainous landscape. We performed a variation partitioning analysis to assess the relative importance of these variables for predicting patterns of functional traits in communities, and projected the best models under several climate change scenarios to examine future potential changes in vegetation functional properties. Not all indices of trait patterns within communities could be modelled with the same level of accuracy: the models for mean and extreme values of functional traits provided substantially better predictive accuracy than the models calibrated for diversity indices. Topographic and climatic factors were more important predictors of functional trait patterns within communities than edaphic predictors. Overall, model projections forecast an increase in mean vegetation height and in mean specific leaf area following climate warming. This trend was important at mid elevation particularly between 1000 and 2000 m asl. With this study we showed that topographic, climatic and edaphic variables can successfully model descriptors of community-level patterns of plant functional traits such as mean and extreme trait values. However, which factors determine the diversity of functional traits in plant communities remains unclear and requires more investigations.
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In past years, comprehensive representations of cell signalling pathways have been developed by manual curation from literature, which requires huge effort and would benefit from information stored in databases and from automatic retrieval and integration methods. Once a reconstruction of the network of interactions is achieved, analysis of its structural features and its dynamic behaviour can take place. Mathematical modelling techniques are used to simulate the complex behaviour of cell signalling networks, which ultimately sheds light on the mechanisms leading to complex diseases or helps in the identification of drug targets. A variety of databases containing information on cell signalling pathways have been developed in conjunction with methodologies to access and analyse the data. In principle, the scenario is prepared to make the most of this information for the analysis of the dynamics of signalling pathways. However, are the knowledge repositories of signalling pathways ready to realize the systems biology promise? In this article we aim to initiate this discussion and to provide some insights on this issue.
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MicroRNAs (miRNAs) are small non-coding RNAs that regulate a variety of biological processes. Cell-free miRNAs detected in blood plasma are used as specific and sensitive markers of physiological processes and some diseases. Circulating miRNAs are highly stable in body fluids, for example plasma. Therefore, profiles of circulating miRNAs have been investigated for potential use as novel, non-invasive anti-doping biomarkers. This review describes the biological mechanisms underlying the variation of circulating miRNAs, revealing that they have great potential as a new class of biomarker for detection of doping substances. The latest developments in extraction and profiling technology, and the technical design of experiments useful for anti-doping, are also discussed. Longitudinal measurements of circulating miRNAs in the context of the athlete biological passport are proposed as an efficient strategy for the use of these new markers. The review also emphasizes potential challenges for the translation of circulating miRNAs from research into practical anti-doping applications.
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Diagnosis in allergology is facing novel challenges because of the availability not only of purified or recombinant allergens, but also of multitests such as allergen micro-arrays. These new diagnostic opportunities contribute to a better understanding of crossreactivities between respiratory and food allergens. In comparison to current diagnosis based on whole allergen extracts, this novel generation of specific IgE tests is expected to provide better information on the risk of reaction to allergens as well as on its severity. However these new technologies are expensive, and will have to be carefully analyzed in terms of medical usefulness and public health costs.
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The performance of magnetic nanoparticles is intimately entwined with their structure, mean size and magnetic anisotropy. Besides, ensembles offer a unique way of engineering the magnetic response by modifying the strength of the dipolar interactions between particles. Here we report on an experimental and theoretical analysis of magnetic hyperthermia, a rapidly developing technique in medical research and oncology. Experimentally, we demonstrate that single-domain cubic iron oxide particles resembling bacterial magnetosomes have superior magnetic heating efficiency compared to spherical particles of similar sizes. Monte Carlo simulations at the atomic level corroborate the larger anisotropy of the cubic particles in comparison with the spherical ones, thus evidencing the beneficial role of surface anisotropy in the improved heating power. Moreover we establish a quantitative link between the particle assembling, the interactions and the heating properties. This knowledge opens new perspectives for improved hyperthermia, an alternative to conventional cancer therapies.
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The treatment of writer's cramp, a task-specific focal hand dystonia, needs new approaches. A deficiency of inhibition in the motor cortex might cause writer's cramp. Transcranial direct current stimulation modulates cortical excitability and may provide a therapeutic alternative. In this randomized, double-blind, sham-controlled study, we investigated the efficacy of cathodal stimulation of the contralateral motor cortex in 3 sessions in 1 week. Assessment over a 2-week period included clinical scales, subjective ratings, kinematic handwriting analysis, and neurophysiological evaluation. Twelve patients with unilateral dystonic writer's cramp were investigated; 6 received transcranial direct current and 6 sham stimulation. Cathodal transcranial direct current stimulation had no favorable effects on clinical scales and failed to restore normal handwriting kinematics and cortical inhibition. Subjective worsening remained unexplained, leading to premature study termination. Repeated sessions of cathodal transcranial direct current stimulation of the motor cortex yielded no favorable results supporting a therapeutic potential in writer's cramp.
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Locally advanced prostate cancer (LAPC) is a heterogeneous entity usually embracing T3-4 and/or pelvic lymph-node-positive disease in the absence of established metastases. Outcomes for LAPC with single therapies have traditionally been poor, leading to the investigation of adjuvant therapies. Prostate cancer is a hormonally sensitive tumour, which usually responds to pharmacological manipulation of the androgen receptor or its testosterone-related ligands. As such, androgen deprivation therapy (ADT) has become an important adjuvant strategy for the treatment of LAPC, particularly for patients managed primarily with radiotherapy. Such results have generally not been replicated in surgical patients. With increased use of ADT has come improved awareness of the numerous toxicities associated with long-term use of these agents, as well as the development of strategies for minimizing ADT exposure and actively managing adverse effects. Several trials are exploring agents to enhance radiation cell sensitivity as well as the application of adjuvant docetaxel, an agent with proven efficacy in the metastatic, castrate-resistant setting. The recent work showing activity of cabazitaxel, sipuleucel-T and abiraterone for castrate-resistant disease in the post-docetaxel setting will see these agents investigated in conjunction with definitive surgery and radiotherapy.