999 resultados para PERMEABILITY FACTOR


Relevância:

20.00% 20.00%

Publicador:

Resumo:

Splenic marginal zone (MZ) B cells are a lineage distinct from follicular and peritoneal B1 B cells. They are located next to the marginal sinus where blood is released. Here they pick up antigens and shuttle the load onto follicular dendritic cells inside the follicle. On activation, MZ B cells rapidly differentiate into plasmablasts secreting antibodies, thereby mediating humoral immune responses against blood-borne type 2 T-independent antigens. As Krüppel-like factors are implicated in cell differentiation/function in various tissues, we studied the function of basic Krüppel-like factor (BKLF/KLF3) in B cells. Whereas B-cell development in the bone marrow of KLF3-transgenic mice was unaffected, MZ B-cell numbers in spleen were increased considerably. As revealed in chimeric mice, this occurred cell autonomously, increasing both MZ and peritoneal B1 B-cell subsets. Comparing KLF3-transgenic and nontransgenic follicular B cells by RNA-microarray revealed that KLF3 regulates a subset of genes that was similarly up-regulated/down-regulated on normal MZ B-cell differentiation. Indeed, KLF3 expression overcame the lack of MZ B cells caused by different genetic alterations, such as CD19-deficiency or blockade of B-cell activating factor-receptor signaling, indicating that KLF3 may complement alternative nuclear factor-κB signaling. Thus, KLF3 is a driving force toward MZ B-cell maturation.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Intensive research is devoted to unravel the neurobiological mechanisms mediating adult hippocampal neurogenesis, its regulation by antidepressants, and its behavioral consequences. Macrophage migration inhibitory factor (MIF) is a pro-inflammatory cytokine that is expressed in the CNS, where its function is unknown. Here, we show, for the first time, the relevance of MIF expression for adult hippocampal neurogenesis. We identify MIF expression in neurogenic cells (in stem cells, cells undergoing proliferation, and in newly proliferated cells undergoing maturation) in the subgranular zone of the rodent dentate gyrus. A causal function for MIF in cell proliferation was shown using genetic (MIF gene deletion) and pharmacological (treatment with the MIF antagonist Iso-1) approaches. Behaviorally, genetic deletion of MIF resulted in increased anxiety- and depression-like behaviors, as well as of impaired hippocampus-dependent memory. Together, our studies provide evidence supporting a pivotal function for MIF in both basal and antidepressant-stimulated adult hippocampal cell proliferation. Moreover, loss of MIF results in a behavioral phenotype that, to a large extent, corresponds with alterations predicted to arise from reduced hippocampal neurogenesis. These findings underscore MIF as a potentially relevant molecular target for the development of treatments linked to deficits in neurogenesis, as well as to problems related to anxiety, depression, and cognition.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Purpose To reduce the incidence of febrile neutropenia during rapid COJEC (cisplatin, vincristine, carboplatin, etoposide, and cyclophosphamide given in a rapid delivery schedule) induction. In the High-Risk Neuroblastoma-1 (HR-NBL1) trial, the International Society of Paediatric Oncology European Neuroblastoma Group (SIOPEN) randomly assigned patients to primary prophylactic (PP) versus symptom-triggered granulocyte colony-stimulating factor (GCSF; filgrastim). Patients and Methods From May 2002 to November 2005, 239 patients in 16 countries were randomly assigned to receive or not receive PPGCSF. There were 144 boys with a median age of 3.1 years (range, 1 to 17 years) of whom 217 had International Neuroblastoma Staging System (INSS) stage 4 and 22 had stage 2 or 3 MYCN-amplified disease. The prophylactic arm received a single daily dose of 5 μg/kg GCSF, starting after each of the eight COJEC chemotherapy cycles and stopping 24 hours before the next cycle. Chemotherapy was administered every 10 days regardless of hematologic recovery, provided that infection was controlled. Results The PPGCSF arm had significantly fewer febrile neutropenic episodes (P = .002), days with fever (P = .004), hospital days (P = .017), and antibiotic days (P = .001). Reported Common Toxicity Criteria (CTC) graded toxicity was also significantly reduced: infections per cycle (P = .002), fever (P < .001), severe leucopenia (P < .001), neutropenia (P < .001), mucositis (P = .002), nausea/vomiting (P = .045), and constipation (P = .008). Severe weight loss was reduced significantly by 50% (P = .013). Protocol compliance with the rapid induction schedule was also significantly better in the PPGCSF arm shown by shorter time to completion (P = .005). PPGCSF did not adversely affect response rates or success of peripheral-blood stem-cell harvest. Following these results, PPG-GSF was advised for all patients on rapid COJEC induction.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

A partir de una breve revisión bibliográfica de las caracteristicas y aplicaciones de la técnica de los tiempos de reacción, se ha planteado una experiencia en la que, siguiendo la linea de Eysenck, se aplica dicha técnica al estudio de la personalidad, concretada aquí en el factor introversión-extroversión. La hipótesis, confirmada en parte por los resultados obtenidos, planteaba en forma afirmativa la existencia de diferencias significativas entre el rendimiento y comportamiento de un grupo de introvertidos, ambivertidos y extrovertidos en unas pruebas de reacciometria.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

We have amplified a (CA)n:(GT)n microsatellite from the TNF promoters of a panel of mouse strains using the polymerase chain reaction. The length of the microsatellites was polymorphic, with eight alleles observed among 15 inbred strains bearing seven distinct H-2 haplotypes, and four outbred strains. In B10 congenic strains, the TNF allele detected by microsatellite polymorphism segregated with the MHC, and in recombinant haplotypes (NOD, NZW), it segregated with H-2D. The TNF allele found in the NZW strain (H-2z) was distinct from those of all other haplotypes, consistent with the hypothesis that this strain may carry a genetic defect in TNF production.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Flood effectiveness observations imply that two families of processes describe the formation of debris flow volume. One is related to the rainfall?erosion relationship, and can be seen as a gradual process, and one is related to additional geological/geotechnical events, those named hereafter extraordinary events. In order to discuss the hypothesis of coexistence of two modes of volume formation, some methodologies are applied. Firstly, classical approaches consisting in relating volume to catchments characteristics are considered. These approaches raise questions about the quality of the data rather than providing answers concerning the controlling processes. Secondly, we consider statistical approaches (cumulative number of events distribution and cluster analysis) and these suggest the possibility of having two distinct families of processes. However the quantitative evaluation of the threshold differs from the one that could be obtained from the first approach, but they all agree in the sense of the coexistence of two families of events. Thirdly, a conceptual model is built exploring how and why debris flow volume in alpine catchments changes with time. Depending on the initial condition (sediment production), the model shows that large debris flows (i.e. with important volume) are observed in the beginning period, before a steady-state is reached. During this second period debris flow volume such as is observed in the beginning period is not observed again. Integrating the results of the three approaches, two case studies are presented showing: (1) the possibility to observe in a catchment large volumes that will never happen again due to a drastic decrease in the sediment availability, supporting its difference from gradual erosion processes; (2) that following a rejuvenation of the sediment storage (by a rock avalanche) the magnitude?frequency relationship of a torrent can be differentiated into two phases, the beginning one with large and frequent debris flow and a later one with debris flow less intense and frequent, supporting the results of the conceptual model. Although the results obtained cannot identify a clear threshold between the two families of processes, they show that some debris flows can be seen as pulse of sediment differing from that expected from gradual erosion.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

STUDY OBJECTIVE: To assess whether having a good relationship with their mother was a protective factor against risky sexual behavior for female adolescents and whether it was independent of family structure. DESIGN: Cross-sectional survey of in-school adolescents aged 14-19 years. SETTING: Catalonia, in northeast Spain. PARTICIPANTS: A total of 3677 females divided according on whether they had a good (n=3335) or a bad (n=342) relationship with their mother. MAIN OUTCOME MEASURES: Rates of sexual activity and sexual behavior. RESULTS: Adolescents in the good relationship group were significantly younger, more likely to live in an intact family, to have a good relationship with their father and siblings, and to talk about sexuality and their partner with their mother. They were also less likely to have ever had sexual intercourse. Among those sexually experienced, they were significantly older at first intercourse and less likely to have multiple partners or a history of STI. After adjusting for potential confounders, females in the good relationship group were less likely to be sexually active and to have had multiple partners, independently of family structure. CONCLUSIONS: Having a good relationship with their mother is a protective factor against sexual intercourse and having multiple sexual partners independently of family structure. Communication between generations and having a good relationship with their father and siblings also play an important role.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Cancer immunotherapy has great promise, but is limited by diverse mechanisms used by tumors to prevent sustained antitumor immune responses. Tumors disrupt antigen presentation, T/NK-cell activation, and T/NK-cell homing through soluble and cell-surface mediators, the vasculature, and immunosuppressive cells such as myeloid-derived suppressor cells and regulatory T cells. However, many molecular mechanisms preventing the efficacy of antitumor immunity have been identified and can be disrupted by combination immunotherapy. Here, we examine immunosuppressive mechanisms exploited by tumors and provide insights into the therapies under development to overcome them, focusing on lymphocyte traffic.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

La reforma del sistema de la Seguridad Social en España, aprobada con la Ley 27/2011, introduce un factor de sostenibilidad, pendiente de aplicación, que complementa una serie de cambios paramétricos en la determinación de las pensiones. El factor de sostenibilidad se vincula a la evolución quinquenal de la variable demográfica esperanza de vida a los 67 años, a partir de un año base de aplicación. Este trabajo pone de manifiesto que, con la revalorización de las pensiones para el año 2012 y 2013 fijada en el Real Decreto-ley 28/2012 y el Real Decreto-ley 29/2012, el Gobierno ha aplicado de forma implícita un factor de sostenibilidad sobre las pensiones ya causadas, basado en variables demográficas y económicas.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Macrophage migration inhibitory factor (MIF), a proinflammatory cytokine, is considered an attractive therapeutic target in multiple inflammatory and autoimmune disorders. In addition to its known biologic activities, MIF can also function as a tautomerase. Several small molecules have been reported to be effective inhibitors of MIF tautomerase activity in vitro. Herein we employed a robust activity-based assay to identify different classes of novel inhibitors of the catalytic and biological activities of MIF. Several novel chemical classes of inhibitors of the catalytic activity of MIF with IC(50) values in the range of 0.2-15.5 microm were identified and validated. The interaction site and mechanism of action of these inhibitors were defined using structure-activity studies and a battery of biochemical and biophysical methods. MIF inhibitors emerging from these studies could be divided into three categories based on their mechanism of action: 1) molecules that covalently modify the catalytic site at the N-terminal proline residue, Pro(1); 2) a novel class of catalytic site inhibitors; and finally 3) molecules that disrupt the trimeric structure of MIF. Importantly, all inhibitors demonstrated total inhibition of MIF-mediated glucocorticoid overriding and AKT phosphorylation, whereas ebselen, a trimer-disrupting inhibitor, additionally acted as a potent hyperagonist in MIF-mediated chemotactic migration. The identification of biologically active compounds with known toxicity, pharmacokinetic properties, and biological activities in vivo should accelerate the development of clinically relevant MIF inhibitors. Furthermore, the diversity of chemical structures and mechanisms of action of our inhibitors makes them ideal mechanistic probes for elucidating the structure-function relationships of MIF and to further determine the role of the oligomerization state and catalytic activity of MIF in regulating the function(s) of MIF in health and disease.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The Early Smoking Experience (ESE) questionnaire is the most widely used questionnaire to assess initial subjective experiences of cigarette smoking. However, its factor structure is not clearly defined and can be perceived from two main standpoints: valence, or positive and negative experiences, and sensitivity to nicotine. This article explores the ESE's factor structure and determines which standpoint was more relevant. It compares two groups of young Swiss men (German- and French-speaking). We examined baseline data on 3,368 tobacco users from a representative sample in the ongoing Cohort Study on Substance Use Risk Factors (C-SURF). ESE, continued tobacco use, weekly smoking and nicotine dependence were assessed. Exploratory structural equation modeling (ESEM) and structural equation modeling (SEM) were performed. ESEM clearly distinguished positive experiences from negative experiences, but negative experiences were divided in experiences related to dizziness and experiences related to irritations. SEM underlined the reinforcing effects of positive experiences, but also of experiences related to dizziness on nicotine dependence and weekly smoking. The best ESE structure for predictive accuracy of experiences on smoking behavior was a compromise between the valence and sensitivity standpoints, which showed clinical relevance.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

There is a wide range of evidence to suggest that permeability can be constrained through of induced polarization measurements. For clean sands and sandstones, current mechanistic models of induced polarization predict a relationship between the low-frequency time constant inferred from induced polarization measurements and the grain diameter. A number of observations do, however, disagree with this and indicate that the observed relaxation behavior is rather governed by the so-called dynamic pore radius L. To test this hypothesis, we have developed a set of new scaling relationships, which allow the relaxation time to be computed from the pore size and the permeability to be computed from both the Cole-Cole time constant and the formation factor. Moreover, these new scaling relationships can be also used to predict the dependence of the Cole-Cole time constant as a function of the water saturation under unsaturated conditions. Comparative tests of the proposed new relationships with regard to various published experimental results for saturated clean sands and sandstones as well as for partially saturated clean sandstones, do indeed confirm that the dynamic pore radius L is a much more reliable indicator of the observed relaxation behavior than grain-size-based models.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The penetration of chloride ions from deicing salts into the portland cement concrete of bridge decks can cause corrosion and serious damage to the reinforcing steel. Concrete properties which prevent chloride penetration into the bridge deck and provide a good structural and economic wearing surface are desirable. A variety of mix designs have been tried in the past in search of improved performance and lower costs for bridge deck overlay concrete. A group of mixes with various designs have been tested in this project and results are being compared to determine which concrete mix appears to be the most cost effective and resistant to chloride penetration for bridge deck overlay use.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

FGFR1 mutations have been identified in both Kallmann syndrome and normosmic HH (nIHH). To date, few mutations in the FGFR1 gene have been structurally or functionally characterized in vitro to identify molecular mechanisms that contribute to the disease pathogenesis. We attempted to define the in vitro functionality of two FGFR1 mutants (R254W and R254Q), resulting from two different amino acid substitutions of the same residue, and to correlate the in vitro findings to the patient phenotypes. Two unrelated GnRH deficient probands were found to harbor mutations in FGFR1 (R254W and R254Q). Mutant signaling activity and expression levels were evaluated in vitro and compared to a wild type (WT) receptor. Signaling activity was determined by a FGF2/FGFR1 dependent transcription reporter assay. Receptor total expression levels were assessed by Western blot and cell surface expression was measured by a radiolabeled antibody binding assay. The R254W maximal receptor signaling capacity was reduced by 45% (p<0.01) while R254Q activity was not different from WT. However, both mutants displayed diminished total protein expression levels (40 and 30% reduction relative to WT, respectively), while protein maturation was unaffected. Accordingly, cell surface expression levels of the mutant receptors were also significantly reduced (35% p<0.01 and 15% p<0.05, respectively). The p.R254W and p.R254Q are both loss-of-function mutations as demonstrated by their reduced overall and cell surface expression levels suggesting a deleterious effect on receptor folding and stability. It appears that a tryptophan substitution at R254 is more disruptive to receptor structure than the more conserved glutamine substitution. No clear correlation between the severity of in vitro loss-of-function and phenotypic presentation could be assigned.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Cilengitide is a high-affinity cyclic pentapeptdic alphaV integrin antagonist previously reported to suppress angiogenesis by inducing anoikis of endothelial cells adhering through alphaVbeta3/alphaVbeta5 integrins. Angiogenic endothelial cells express multiple integrins, in particular those of the beta1 family, and little is known on the effect of cilengitide on endothelial cells expressing alphaVbeta3 but adhering through beta1 integrins. Through morphological, biochemical, pharmacological and functional approaches we investigated the effect of cilengitide on alphaVbeta3-expressing human umbilical vein endothelial cells (HUVEC) cultured on the beta1 ligands fibronectin and collagen I. We show that cilengitide activated cell surface alphaVbeta3, stimulated phosphorylation of FAK (Y(397) and Y(576/577)), Src (S(418)) and VE-cadherin (Y(658) and Y(731)), redistributed alphaVbeta3 at the cell periphery, caused disappearance of VE-cadherin from cellular junctions, increased the permeability of HUVEC monolayers and detached HUVEC adhering on low-density beta1 integrin ligands. Pharmacological inhibition of Src kinase activity fully prevented cilengitide-induced phosphorylation of Src, FAK and VE-cadherin, and redistribution of alphaVbeta3 and VE-cadherin and partially prevented increased permeability, but did not prevent HUVEC detachment from low-density matrices. Taken together, these observations reveal a previously unreported effect of cilengitide on endothelial cells namely its ability to elicit signaling events disrupting VE-cadherin localization at cellular contacts and to increase endothelial monolayer permeability. These effects are potentially relevant to the clinical use of cilengitide as anticancer agent.