860 resultados para Complexity reduction


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Sarcomas are heterogeneous and aggressive mesenchymal tumors. Histological grading has so far been the best predictor for metastasis-free survival, but it has several limitations, such as moderate reproducibility and poor prognostic value for some histological types. To improve patient grading, we performed genomic and expression profiling in a training set of 183 sarcomas and established a prognostic gene expression signature, complexity index in sarcomas (CINSARC), composed of 67 genes related to mitosis and chromosome management. In a multivariate analysis, CINSARC predicts metastasis outcome in the training set and in an independent 127 sarcomas validation set. It is superior to the Fédération Francaise des Centres de Lutte Contre le Cancer grading system in determining metastatic outcome for sarcoma patients. Furthermore, it also predicts outcome for gastrointestinal stromal tumors (GISTs), breast carcinomas and lymphomas. Application of the signature will permit more selective use of adjuvant therapies for people with sarcomas, leading to decreased iatrogenic morbidity and improved outcomes for such individuals.

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Background:  The relationship between phoneme awareness, rapid automatized naming (RAN), verbal short-term/working memory (ST/WM) and diagnostic category is investigated in control and dyslexic children, and the extent to which this depends on orthographic complexity. Methods:  General cognitive, phonological and literacy skills were tested in 1,138 control and 1,114 dyslexic children speaking six different languages spanning a large range of orthographic complexity (Finnish, Hungarian, German, Dutch, French, English). Results:  Phoneme deletion and RAN were strong concurrent predictors of developmental dyslexia, while verbal ST/WM and general verbal abilities played a comparatively minor role. In logistic regression models, more participants were classified correctly when orthography was more complex. The impact of phoneme deletion and RAN-digits was stronger in complex than in less complex orthographies. Conclusions:  Findings are largely consistent with the literature on predictors of dyslexia and literacy skills, while uniquely demonstrating how orthographic complexity exacerbates some symptoms of dyslexia.

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AimSmall body size in Madagascar's dwarf and mouse lemurs (Cheirogaleidae) is generally viewed as primitive. We investigated the evolution of body size in this family and in its sister-taxon, the Lepilemuridae, from phylogenetic, ontogenetic and adaptive perspectives. LocationMadagascar. MethodsWe used a phylogenetic method to reconstruct the evolution of body size in lemurs, and allometric regression models of gestation periods and static and growth allometries in Cheirogaleidae and Lepilemuridae to test the hypothesis that dwarfing occurred as a result of truncated ontogeny (progenesis). We also examined adaptive hypotheses relating body size to environmental variability, life history, seasonality of reproduction, hypothermy (use of torpor), and a diet rich in plant exudates. ResultsOur results indicated that cheirogaleids experienced at least four independent events of body size reduction from an ancestor as large as living Lepilemuridae, by means of progenesis. Our interpretation is supported by the paedomorphic appearance and parallel ontogenetic trajectories of the dwarf taxa, as well as their very short gestation periods and increased fecundity. Lepilemur species that occupy more predictable environments are significantly larger than those occupying unpredictable habitats. Main conclusionsCheirogaleidae appear to be paedomorphic dwarfs, a consequence of progenesis, probably as an adaptation to high environmental unpredictability. Although the capacity to use hypothermy is related to small body size, this advantage is unlikely to have driven dwarfing in cheirogaleids. We propose that gummmivory/exudativory co-evolved with body size reduction in this clade, probably from a folivorous ancestor. Their small size is derived, and their suitability as models for the ancestral primate' is therefore dubious.

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The results of a crystal structure refinement of an anisotropic grandite garnet specimen with composition Gro36-4 And63-6 are given. The structure obtained has orthorrombic symmetry (space group Fddd) and is compared with similar results obtained by other authors. In all cases the reduction of symmetry is due to the ordering of Fe3+ and Al in octahedral sites. Non cubic structures of grandites are discussed in connection with optical, morphological an grou-th features of these minerals.

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Expression based prediction of gene alterations identified WNT inhibitory factor I (WIF1) as a new candidate tumor suppressor gene involved in glioblastoma. WIF1 encodes a secreted WNT antagonist and it is strongly down-regulated in most glioblastoma as compared to normal brain both by genomic deletion and WIF1 promoter hypermethylation. WIF1 expression in glioblastoma cell lines inhibited cell proliferation in vitro and in vivo and strongly reduced migration capability. Interestingly, WIF1 expression induced a senescence-like phenotype characterized by the appearance of enlarged, flattened and multinucleated cells positive for the presence of senescence associated ß-galactosidase, a late marker of senescence. It is of note that WIF1 induced senescence, in glioma cell lines, is independent of either p53 or pRB, two pathways that have been widely associated with this process. The analysis of the signaling pathways downstream of WIF1 brought some interesting results. WIF1 expression inhibited the canonical pathway but alteration of this pathway alone couldn't explain all the WIFl-induced effects. Some WIF1-related changes were attributed to inhibition of the non-canonical pathway, as we could prove by downregulation of WNT5a, the main ligand of the non-canonical WNT pathway. For example, a drastic reduction of phosphorylation of both ERK and p38 was detected when either overexpressing WIF1 or downregulating WNT5a. Due to the complexity of the non-canonical pathway is difficult to define the precise mechanism of signal transduction. We have excluded the involvement of the WNT5a-JNK-APl pathway and preliminary results suggest the implication of the WNT-calcium signaling, but further evidence is needed. Moreover, from the analysis of the gene expression profile of WIF1 expressing cells we could select a very interesting candidate: MALATI, a non-coding RNA widely associated with migratory capability in many different types of tumors. We found MALATI to be overexpressed in glioblastoma specimens compared to normal brain and to be associated with total tumor volume. The downregulation of MALATI by RNAi (RNA interference] drastically impairs migration, thus it is a very interesting potential target in the context of invasive tumors such as glioblastoma. Résumé WIFl a été sélectionné en tant que putatif suppresseur de tumeurs dans le cadre des glioblastomes par une analyse qui a était conduit à partir des données d'expression de gènes provenant d'environ 80 glioblastomes. WIF1 code pour une protéine destinée à la sécrétion qui antagonise la voie de WNT et son expression est fortement sous-exprimé dans la plupart des glioblastome par rapport à tissu cérébral normal. Cette sous-expression est due à deux mécanismes différents: à la délétion de la partie génomique codant pour WIF1 et à l'hyper méthylation de son promoteur. La surexpression de WIF1 réduit la capacité de prolifération des cellules de glioblastome in vitro ainsi que in vivo et elle réduit aussi leur capacité migratoire. Il est intéressant de remarquer que l'espression de WIF1 induit un phénotype sénescent caractérisé par l'apparition de cellules aplaties, multi nucléées et positives pour l'activité de l'enzyme ß-galactosidase associée à la sénescence, un marqueur tardif de la sénescence. Il est à noter que le phénotype sénescent qui est induit par WIF1 est indépendant de p53 et pRB, deux voies qui ont été largement associées à ce processus. L'analyse des les voies de signalisation en aval de WIFl a apporté des résultats intéressants. L'expression de WIF1 inhibe la voie canonique de WNT, mais l'altération de cette voie seule ne pouvait pas expliquer tous les effets induits par WIF1. Nous avons pu prouver que certains changements sont liés à l'inhibition de la voie non-canonique qui est activée par WNT5cc. Par exemple, une réduction drastique de la phosphorylation de ERK et p38 à la fois a été détectée lorsque WIFl a été surexprimé ou WNT5a sous- exprimé. En raison de la complexité de la voie non-canonique, il est difficile de définir le mécanisme précis de la transduction du signal. Nous avons exclu l'implication de la voie JNK-WNT5a-APl et les résultats préliminaires suggèrent l'implication de la voie de signalisation appelée WNT-calcium. En plus, l'analyse du profil d'expression génique de cellules sur-exprimant WIF1 nous a permis d'identifier un candidat très intéressant: MALATI, un ARN non- codants largement associés à la capacité migratoire dans nombreux types de tumeurs. Nous avons trouvé que MALATI est surexprimé dans les échantillons de glioblastome par rapport à tissu cérébral normal et il est associé au volume total de la tumeur. La sous-expression de MALATI altère considérablement la migration des cellules tumorales. Donc, MALATI, est une cible potentielle très intéressante dans le cadre d'une tumeur invasive telle que le glioblastome.

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The pharmacokinetics (PK) of efavirenz (EFV) is characterized by marked interpatient variability that correlates with its pharmacodynamics (PD). In vitro-in vivo extrapolation (IVIVE) is a "bottom-up" approach that combines drug data with system information to predict PK and PD. The aim of this study was to simulate EFV PK and PD after dose reductions. At the standard dose, the simulated probability was 80% for viral suppression and 28% for central nervous system (CNS) toxicity. After a dose reduction to 400 mg, the probabilities of viral suppression were reduced to 69, 75, and 82%, and those of CNS toxicity were 21, 24, and 29% for the 516 GG, 516 GT, and 516 TT genotypes, respectively. With reduction of the dose to 200 mg, the probabilities of viral suppression decreased to 54, 62, and 72% and those of CNS toxicity decreased to 13, 18, and 20% for the 516 GG, 516 GT, and 516 TT genotypes, respectively. These findings indicate how dose reductions might be applied in patients with favorable genetic characteristics.

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BACKGROUND: Increasingly, patients receiving methadone treatment are found in low threshold facilities (LTF), which provide needle exchange programmes in Switzerland. This paper identifies the characteristics of LTF attendees receiving methadone treatment (MT) compared with other LTF attendees (non-MT). METHODS: A national cross-sectional survey was conducted in 2006 over five consecutive days in all LTF (n=25). Attendees were given an anonymous questionnaire, collecting information on socio-demographic indicators, drug consumption, injection, methadone treatment, and self-reported HIV and HCV status. Univariate analysis and logistic regression were performed to compare MT to non-MT. The response rate was 66% (n=1128). RESULTS: MT comprised 57.6% of the sample. In multivariate analysis, factors associated with being on MT were older age (OR: 1.38), being female (OR: 1.60), having one's own accommodation (OR: 1.56), receiving public assistance (OR: 2.29), lifetime injecting (OR: 2.26), HIV-positive status (OR: 2.00), and having consumed cocaine during the past month (OR: 1.37); MT were less likely to have consumed heroin in the past month (OR: 0.76, not significant) and visited LTF less often on a daily basis (OR: 0.59). The number of injections during the past week was not associated with MT. CONCLUSIONS: More LTF attendees were in the MT group, bringing to light an underappreciated LTF clientele with specific needs. The MT group consumption profile may reflect therapeutic failure or deficits in treatment quality and it is necessary to acknowledge this and to strengthen the awareness of LTF personnel about potential needs of MT attendees to meet their therapeutic goals.

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BACKGROUND: New evidence shows that high density lipoproteins (HDL) have protective effects beyond their role in reverse cholesterol transport. Reconstituted HDL (rHDL) offer an attractive means of clinically exploiting these novel effects including cardioprotection against ischemia reperfusion injury (IRI). However, basic rHDL composition is limited to apolipoprotein AI (apoAI) and phospholipids; addition of bioactive compound may enhance its beneficial effects. OBJECTIVE: The aim of this study was to investigate the role of rHDL in post-ischemic model, and to analyze the potential impact of sphingosine-1-phosphate (S1P) in rHDL formulations. METHODS AND RESULTS: The impact of HDL on IRI was investigated using complementary in vivo, ex vivo and in vitro IRI models. Acute post-ischemic treatment with native HDL significantly reduced infarct size and cell death in the ex vivo, isolated heart (Langendorff) model and the in vivo model (-48%, p<0.01). Treatment with rHDL of basic formulation (apoAI + phospholipids) had a non-significant impact on cell death in vitro and on the infarct size ex vivo and in vivo. In contrast, rHDL containing S1P had a highly significant, protective influence ex vivo, and in vivo (-50%, p<0.01). This impact was comparable with the effects observed with native HDL. Pro-survival signaling proteins, Akt, STAT3 and ERK1/2 were similarly activated by HDL and rHDL containing S1P both in vitro (isolated cardiomyocytes) and in vivo. CONCLUSION: HDL afford protection against IRI in a clinically relevant model (post-ischemia). rHDL is significantly protective if supplemented with S1P. The protective impact of HDL appears to target directly the cardiomyocyte.

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Today's approach to anti-doping is mostly centered on the judicial process, despite pursuing a further goal in the detection, reduction, solving and/or prevention of doping. Similarly to decision-making in the area of law enforcement feeding on Forensic Intelligence, anti-doping might significantly benefit from a more extensive gathering of knowledge. Forensic Intelligence might bring a broader logical dimension to the interpretation of data on doping activities for a more future-oriented and comprehensive approach instead of the traditional case-based and reactive process. Information coming from a variety of sources related to doping, whether directly or potentially, would feed an organized memory to provide real time intelligence on the size, seriousness and evolution of the phenomenon. Due to the complexity of doping, integrating analytical chemical results and longitudinal monitoring of biomarkers with physiological, epidemiological, sociological or circumstantial information might provide a logical framework enabling fit for purpose decision-making. Therefore, Anti-Doping Intelligence might prove efficient at providing a more proactive response to any potential or emerging doping phenomenon or to address existing problems with innovative actions or/and policies. This approach might prove useful to detect, neutralize, disrupt and/or prevent organized doping or the trafficking of doping agents, as well as helping to refine the targeting of athletes or teams. In addition, such an intelligence-led methodology would serve to address doping offenses in the absence of adverse analytical chemical evidence.

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AbstractIn addition to genetic changes affecting the function of gene products, changes in gene expression have been suggested to underlie many or even most of the phenotypic differences among mammals. However, detailed gene expression comparisons were, until recently, restricted to closely related species, owing to technological limitations. Thus, we took advantage of the latest technologies (RNA-Seq) to generate extensive qualitative and quantitative transcriptome data for a unique collection of somatic and germline tissues from representatives of all major mammalian lineages (placental mammals, marsupials and monotremes) and birds, the evolutionary outgroup.In the first major project of my thesis, we performed global comparative analyses of gene expression levels based on these data. Our analyses provided fundamental insights into the dynamics of transcriptome change during mammalian evolution (e.g., the rate of expression change across species, tissues and chromosomes) and allowed the exploration of the functional relevance and phenotypic implications of transcription changes at a genome-wide scale (e.g., we identified numerous potentially selectively driven expression switches).In a second project of my thesis, which was also based on the unique transcriptome data generated in the context of the first project we focused on the evolution of alternative splicing in mammals. Alternative splicing contributes to transcriptome complexity by generating several transcript isoforms from a single gene, which can, thus, perform various functions. To complete the global comparative analysis of gene expression changes, we explored patterns of alternative splicing evolution. This work uncovered several general and unexpected patterns of alternative splicing evolution (e.g., we found that alternative splicing evolves extremely rapidly) as well as a large number of conserved alternative isoforms that may be crucial for the functioning of mammalian organs.Finally, the third and final project of my PhD consisted in analyzing in detail the unique functional and evolutionary properties of the testis by exploring the extent of its transcriptome complexity. This organ was previously shown to evolve rapidly both at the phenotypic and molecular level, apparently because of the specific pressures that act on this organ and are associated with its reproductive function. Moreover, my analyses of the amniote tissue transcriptome data described above, revealed strikingly widespread transcriptional activity of both functional and nonfunctional genomic elements in the testis compared to the other organs. To elucidate the cellular source and mechanisms underlying this promiscuous transcription in the testis, we generated deep coverage RNA-Seq data for all major testis cell types as well as epigenetic data (DNA and histone methylation) using the mouse as model system. The integration of these complete dataset revealed that meiotic and especially post-meiotic germ cells are the major contributors to the widespread functional and nonfunctional transcriptome complexity of the testis, and that this "promiscuous" spermatogenic transcription is resulting, at least partially, from an overall transcriptionally permissive chromatin state. We hypothesize that this particular open state of the chromatin results from the extensive chromatin remodeling that occurs during spermatogenesis which ultimately leads to the replacement of histones by protamines in the mature spermatozoa. Our results have important functional and evolutionary implications (e.g., regarding new gene birth and testicular gene expression evolution).Generally, these three large-scale projects of my thesis provide complete and massive datasets that constitute valuables resources for further functional and evolutionary analyses of mammalian genomes.

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In this paper we examine in detail the implementation, with its associated difficulties, of the Killing conditions and gauge fixing into the variational principle formulation of Bianchi-type cosmologies. We address problems raised in the literature concerning the Lagrangian and the Hamiltonian formulations: We prove their equivalence, make clear the role of the homogeneity preserving diffeomorphisms in the phase space approach, and show that the number of physical degrees of freedom is the same in the Hamiltonian and Lagrangian formulations. Residual gauge transformations play an important role in our approach, and we suggest that Poincaré transformations for special relativistic systems can be understood as residual gauge transformations. In the Appendixes, we give the general computation of the equations of motion and the Lagrangian for any Bianchi-type vacuum metric and for spatially homogeneous Maxwell fields in a nondynamical background (with zero currents). We also illustrate our counting of degrees of freedom in an appendix.

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We study the dynamics of generic reaction-diffusion fronts, including pulses and chemical waves, in the presence of multiplicative noise. We discuss the connection between the reaction-diffusion Langevin-like field equations and the kinematic (eikonal) description in terms of a stochastic moving-boundary or sharp-interface approximation. We find that the effective noise is additive and we relate its strength to the noise parameters in the original field equations, to first order in noise strength, but including a partial resummation to all orders which captures the singular dependence on the microscopic cutoff associated with the spatial correlation of the noise. This dependence is essential for a quantitative and qualitative understanding of fluctuating fronts, affecting both scaling properties and nonuniversal quantities. Our results predict phenomena such as the shift of the transition point between the pushed and pulled regimes of front propagation, in terms of the noise parameters, and the corresponding transition to a non-Kardar-Parisi-Zhang universality class. We assess the quantitative validity of the results in several examples including equilibrium fluctuations and kinetic roughening. We also predict and observe a noise-induced pushed-pulled transition. The analytical predictions are successfully tested against rigorous results and show excellent agreement with numerical simulations of reaction-diffusion field equations with multiplicative noise.

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The induction of fungal metabolites by fungal co-cultures grown on solid media was explored using multi-well co-cultures in 2 cm diameter Petri dishes. Fungi were grown in 12-well plates to easily and rapidly obtain the large number of replicates necessary for employing metabolomic approaches. Fungal culture using such a format accelerated the production of metabolites by several weeks compared with using the large-format 9 cm Petri dishes. This strategy was applied to a co-culture of a Fusarium and an Aspergillus strain. The metabolite composition of the cultures was assessed using ultra-high pressure liquid chromatography coupled to electrospray ionisation and time-of-flight mass spectrometry, followed by automated data mining. The de novo production of metabolites was dramatically increased by nutriment reduction. A time-series study of the induction of the fungal metabolites of interest over nine days revealed that they exhibited various induction patterns. The concentrations of most of the de novo induced metabolites increased over time. However, interesting patterns were observed, such as with the presence of some compounds only at certain time points. This result indicates the complexity and dynamic nature of fungal metabolism. The large-scale production of the compounds of interest was verified by co-culture in 15 cm Petri dishes; most of the induced metabolites of interest (16/18) were found to be produced as effectively as on a small scale, although not in the same time frames. Large-scale production is a practical solution for the future production, identification and biological evaluation of these metabolites.