992 resultados para MOMENT GENERATING FUNCTION
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Microcirculation (2010) 17, 69-78. doi: 10.1111/j.1549-8719.2010.00002.x Abstract Background: This study was designed to explore the effect of transient inducible nitric oxide synthase (iNOS) overexpression via cationic liposome-mediated gene transfer on cardiac function, fibrosis, and microvascular perfusion in a porcine model of chronic ischemia. Methods and Results: Chronic myocardial ischemia was induced using a minimally invasive model in 23 landrace pigs. Upon demonstration of heart failure, 10 animals were treated with liposome-mediated iNOS-gene-transfer by local intramyocardial injection and 13 animals received a sham procedure to serve as control. The efficacy of this iNOS-gene-transfer was demonstrated for up to 7 days by reverse transcriptase-polymerase chain reaction in preliminary studies. Four weeks after iNOS transfer, magnetic resonance imaging showed no effect of iNOS overexpression on cardiac contractility at rest and during dobutamine stress (resting ejection fraction: control 27%, iNOS 26%; P = ns). Late enhancement, infarct size, and the amount of fibrosis were similar between groups. Although perfusion and perfusion reserve in response to adenosine and dobutamine were not significantly modified by iNOS-transfer, both vessel number and diameter were significantly increased in the ischemic area in the iNOS-treated group versus control (point score: control 15.3, iNOS 34.7; P < 0.05). Conclusions: Our findings demonstrate that transient iNOS overexpression does not aggravate cardiac dysfunction or postischemic fibrosis, while potentially contributing to neovascularization in the chronically ischemic heart.
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SUMMARY Nuclear factor kappa B (NF-κB) transcription factors control many aspects of cell fate through induction of inflammatory, immune or survival molecules. We have identified two novel proteins, named receptor interacting protein (RIP)-4 and caspase recruitment domain (CARD) adaptor inducing interferon-β (Cardif), which activate NF-κB. Further, we have found that Cardif plays a prominent antiviral function. Antiviral innate immunity is mounted upon recognition by the host of virally associated structures like double-stranded (ds) RNA, which constitutes a viral replication product of many viruses within infected cells. dsRNA, depending on its subcellular localization, can be sensed by two separate arms of host defense. Firstly, Toll-like receptor (TLR)-3, a member of the type I transmembrane TLR family, recognizes endosomally-located dsRNA. Secondly, cytoplasmic dsRNA is detected by the recently identified RNA helicase retinoic acid inducible gene I (RIG-I). Triggering of TLR3- and RIG-I-dependent pathways results in the activation of the transcription factors NF-κB and Interferon regulatory factor (IRF)-3, which cooperatively transduce antiviral immune responses. We have demonstrated that RIP1, a kinase previously shown to be required for TNF signaling, transmits TLR3-dependent NF-κB activation. Further we have identified and characterized Cardif as an essential adaptor transmitting RIG-I-mediated antiviral responses, including activation of NF-κB and IRF3. In addition, we showed that Cardif is cleaved and inactivated by a serine protease of hepatitis C virus, and therefore may represent an attractive target for this virus to escape innate immune responses. RESUME Les facteurs de transcription "nuclear factor kappa B" (NF-κB) contrôlent divers aspects du devenir cellulaire à travers l'induction de molécules inflammatoires, immunitaires ou de survie. Nous avons identifié deux nouvelles protéines, nommées "receptor interacting protein" (RIP)-4 et "caspase recruitment domain (CARD) adaptor inducing interferon-β" (Cardif), qui activent NF-κB. En outre, nous avons trouvé que Cardif joue un rôle antiviral crucial. L'immunité innée antivirale s'établit au moment de la reconnaissance par l'hôte de structures virales, comme l'ARN double brin, qui constitue un produit de réplication de beaucoup de virus à l'intérieur de cellules infectées. L'ARN double brin, dépendant de sa localisation subcellulaire, peut être détecté par deux branches de défense distinctes. Premièrement, le récepteur transmembranaire "Toll-like" (TLR), TLR3, reconnaît l'ARN double brin lorsque localisé dans les endosomes. Deuxièmement, l'ARN double brin cytoplasmique est reconnu par l'ARN hélicase récemment décrite "retinoic acid inducible gene I" (RIG-I). Le déclenchement de voies dépendantes de TLR3 et RIG-I active les facteurs de transcription NF-κB et IRF3, qui coopèrent afin de transduire des réponses immunitaires antivirales. Nous avons démontré que RIP1, une kinase décrite précédemment dans le signalement du TNF, transmet l'activation de NF-κB dépendante de TLR3. De plus, nous avons identifié et caractérisé Cardif comme un adapteur essentiel transmettant les réponses antivirales médiées par RIG-I, qui incluent l'activation de NF-κB et IRF3. De surcroît, Cardif est clivé et inactivé par une sérine protéase du virus de l'hépatite C, et ainsi pourrait représenter une cible attractive pour ce virus afin d'échapper aux réponses immunitaires innées.
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Relevant features of the dynamic structure function S(q,¿) in 3-4He mixtures at zero temperature are investigated starting from known properties of the ground state. Sum rules are used to fix rigorous constraints to the different contributions to S(q,¿), coming from 3He and 4He elementary excitations, as well as to explore the role of the cross term S(3,4)(q,¿). Both the low-q (phonon-roton 4He excitations and 1p-1h 3He excitations) and high-q (deep-inelastic-scattering) ranges are discussed.
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Objectif Un bolus unique d'étomidate inhibe une enzyme mitochondriale impliquée dans la synthèse du cortisol. Au sein de notre institution, tout patient candidat à une chirurgie cardiaque reçoit de l'étomidate à l'induction de l'anesthésie. L'objectif de cette étude a été de déterminer l'incidence des dysfonctions surrénaliennes chez les patients bénéficiant d'une chirurgie cardiaque et nécessitant de hautes doses de noradrénaline au cours de la période postopératoire. Type d'étude Étude rétrospective descriptive dans l'unité de réanimation d'un centre hospitalier universitaire. Patients et méthodes Soixante-trois patients admis en réanimation après chirurgie cardiaque nécessitant plus de 0,2μg/kg par minute de noradrénaline au cours des premières 48 heures postopératoires ont été étudiés. L'insuffisance surrénalienne absolue a été définie par un cortisol basal inférieur à 414nmo/l (15μg/dl), l'insuffisance surrénalienne relative par un cortisol basal entre 414nmo/l (15μg/dl) et 938nmo/l (34μg/dl) avec une augmentation de la cortisolémie (à 60 minutes après un test de stimulation par 250μg de corticotropine de synthèse) inférieure à 250nmo/l (9μg/dl). Résultats Quatorze patients (22 %) ont présenté une fonction surrénalienne normale, 10 (16 %) une insuffisance surrénalienne absolue et 39 (62 %) une insuffisance surrénalienne relative. Tous les patients ont reçu une substitution stéroïdienne, sans aucune différence d'évolution clinique entre les différents groupes. Conclusion L'incidence de l'insuffisance surrénalienne chez les patients qui ont reçu un bolus d'étomidate à l'induction, lors d'une chirurgie cardiaque avec circulation extracorporelle, et présenté une défaillance circulatoire postopératoire, est élevée.
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Although the determination of remaining phosphorus (Prem) is simple, accurate values could also be estimated with a pedotransfer function (PTF) aiming at the additional use of soil analysis data and/or Prem replacement by an even simpler determination. The purpose of this paper was to develop a pedotransfer function to estimate Prem values of soils of the State of São Paulo based on properties with easier or routine laboratory determination. A pedotransfer function was developed by artificial neural networks (ANN) from a database of Prem values, pH values measured in 1 mol L-1 NaF solution (pH NaF) and soil chemical and physical properties of samples collected during soil classification activities carried out in the State of São Paulo by the Agronomic Institute of Campinas (IAC). Furthermore, a pedotransfer function was developed by regressing Prem values against the same predictor variables of the ANN-based PTF. Results showed that Prem values can be calculated more accurately with the ANN-based pedotransfer function with the input variables pH NaF values along with the sum of exchangeable bases (SB) and the exchangeable aluminum (Al3+) soil content. In addition, the accuracy of the Prem estimates by ANN-based PTF were more sensitive to increases in the experimental database size. Although the database used in this study was not comprehensive enough for the establishment of a definitive pedotrasnfer function for Prem estimation, results indicated the inclusion of Prem and pH NaF measurements among the soil testing evaluations as promising ind order to provide a greater database for the development of an ANN-based pedotransfer function for accurate Prem estimates from pH NaF, SB, and Al3+ values.
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Intracellular glucose signalling pathways control the secretion of glucagon and insulin by pancreatic islet α- and β-cells, respectively. However, glucose also indirectly controls the secretion of these hormones through regulation of the autonomic nervous system that richly innervates this endocrine organ. Both parasympathetic and sympathetic nervous systems also impact endocrine pancreas postnatal development and plasticity in adult animals. Defects in these autonomic regulations impair β-cell mass expansion during the weaning period and β-cell mass adaptation in adult life. Both branches of the autonomic nervous system also regulate glucagon secretion. In type 2 diabetes, impaired glucose-dependent autonomic activity causes the loss of cephalic and first phases of insulin secretion, and impaired suppression of glucagon secretion in the postabsorptive phase; in diabetic patients treated with insulin, it causes a progressive failure of hypoglycaemia to trigger the secretion of glucagon and other counterregulatory hormones. Therefore, identification of the glucose-sensing cells that control the autonomic innervation of the endocrine pancreatic and insulin and glucagon secretion is an important goal of research. This is required for a better understanding of the physiological control of glucose homeostasis and its deregulation in diabetes. This review will discuss recent advances in this field of investigation.
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We propose an equation to calculate the intensity correlation function of a dye-laser model with a pump parameter subject to finite-bandwidth fluctuations. The equation is valid, in the weak-noise limit, for all times. It incorporates novel non-Markovian features. Results are given for the short-time behavior of the correlation function. It exhibits a characteristic initial plateau. Our findings are supported by a numerical simulation of the model.
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The relationship between the binding of Vicia villosa (VV) lectin and the expression of cytolytic function in T lymphoblasts has been investigated using flow cytofluorometric techniques. Spleen cells activated in vitro in 5-day mixed leukocyte cultures (MLC) were incubated sequentially with VV, rabbit anti-V antiserum, and fluoresceinated sheep anti-rabbit IgG. When these stained MLC cells were passed on a flow cytometer gated to exclude nonviable cells and small lymphocytes, a single heterogeneous peak of fluorescence was seen, as compared to control MLC cells that had not been incubated with VV. Fluorescence of lymphoblasts was dependent upon lectin dose and was eliminated when staining was performed in the presence of N-acetyl-D-galactosamine, the appropriate competitive sugar for VV. T cell blast populations activated against H-2, Mls, or parasite antigens all had comparable levels of fluorescence after staining with VV, although the cytolytic activity of these cells varied widely. Furthermore, when MLC lymphoblasts binding large or small amounts of VV were sorted on the basis of their relative fluorescence intensity and tested for cytolytic function, no appreciable difference in activity between the 2 populations was observed. These results are inconsistent with the hypothesis that VV binds selectively to cytolytic T lymphocytes.
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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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We have used an axially symmetric deformed Thomas-Fermi model to evaluate the fission barrier of 240Pu as a function of the quadrupole moment Q2 for different values of the angular momentum L and temperature T. The fission stability diagram of this nucleus is investigated.
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Cellular directional migration in an electric field (galvanotaxis) is one of the mechanisms guiding cell movement in embryogenesis and in skin epidermal repair. The epithelial sodium channel (ENaC), in addition to its function of regulating sodium transport in kidney, has recently been found to modulate cell locomotory speed. Here we tested whether ENaC has an additional function of mediating the directional migration of galvanotaxis in keratinocytes. Genetic depletion of ENaC completely blocks only galvanotaxis and does not decrease migration speed. Overexpression of ENaC is sufficient to drive galvanotaxis in otherwise unresponsive cells. Pharmacologic blockade or maintenance of the open state of ENaC also decreases or increases, respectively, galvanotaxis, suggesting that the channel open state is responsible for the response. Stable lamellipodial extensions formed at the cathodal sides of wild-type cells at the start of galvanotaxis; these were absent in the ENaC knockout keratinocytes, suggesting that ENaC mediates galvanotaxis by generating stable lamellipodia that steer cell migration. We provide evidence that ENaC is required for directional migration of keratinocytes in an electric field, supporting a role for ENaC in skin wound healing.
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