50 resultados para ANALYTIC ULTRACENTRIFUGATION
em Université de Lausanne, Switzerland
Resumo:
Variables measured during static and dynamic pupillometry were factor-analyzed. Following factors were obtained regardless whether investigations were carried out in normals or in psychiatric patients: A static factor, a dynamic factor, a stimulus-specific factor and a restitution-dependent factor. Evaluation of reliability in normals demonstrated a high reliability for the static variables of pupillometry.
Resumo:
The complex relationship between structural and functional connectivity, as measured by noninvasive imaging of the human brain, poses many unresolved challenges and open questions. Here, we apply analytic measures of network communication to the structural connectivity of the human brain and explore the capacity of these measures to predict resting-state functional connectivity across three independently acquired datasets. We focus on the layout of shortest paths across the network and on two communication measures-search information and path transitivity-which account for how these paths are embedded in the rest of the network. Search information is an existing measure of information needed to access or trace shortest paths; we introduce path transitivity to measure the density of local detours along the shortest path. We find that both search information and path transitivity predict the strength of functional connectivity among both connected and unconnected node pairs. They do so at levels that match or significantly exceed path length measures, Euclidean distance, as well as computational models of neural dynamics. This capacity suggests that dynamic couplings due to interactions among neural elements in brain networks are substantially influenced by the broader network context adjacent to the shortest communication pathways.
Resumo:
Although extended secondary prophylaxis with low-molecular-weight heparin was recently shown to be more effective than warfarin for cancer-related venous thromboembolism, its cost-effectiveness compared to traditional prophylaxis with warfarin is uncertain. We built a decision analytic model to evaluate the clinical and economic outcomes of a 6-month course of low-molecular-weight heparin or warfarin therapy in 65-year-old patients with cancer-related venous thromboembolism. We used probability estimates and utilities reported in the literature and published cost data. Using a US societal perspective, we compared strategies based on quality-adjusted life-years (QALYs) and lifetime costs. The incremental cost-effectiveness ratio of low-molecular-weight heparin compared with warfarin was 149,865 dollars/QALY. Low-molecular-weight heparin yielded a quality-adjusted life expectancy of 1.097 QALYs at the cost of 15,329 dollars. Overall, 46% (7108 dollars) of the total costs associated with low-molecular-weight heparin were attributable to pharmacy costs. Although the low-molecular-weigh heparin strategy achieved a higher incremental quality-adjusted life expectancy than the warfarin strategy (difference of 0.051 QALYs), this clinical benefit was offset by a substantial cost increment of 7,609 dollars. Cost-effectiveness results were sensitive to variation of the early mortality risks associated with low-molecular-weight heparin and warfarin and the pharmacy costs for low-molecular-weight heparin. Based on the best available evidence, secondary prophylaxis with low-molecular-weight heparin is more effective than warfarin for cancer-related venous thromboembolism. However, because of the substantial pharmacy costs of extended low-molecular-weight heparin prophylaxis in the US, this treatment is relatively expensive compared with warfarin.
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On the basis of serologic cross-reactivity, three immunoglobulin classes homologous to human IgG, IgM and IgA were identified in two species of acquatic mammal representing the orders Cetacea (dolphin) and Pinnipedea (sea lion). Molecular size was estimated by sucrose density gradient ultracentrifugation and Sephadex G-200 chromatography, indicating a 7S IgG, 19S IgM and heterogeneous serum IgA. Human secretory component was readily bound to the IgM of both species and to an apparently lesser extent to the larger molecular size populations of IgA. No binding was observed with IgG. Several antisera specific for human γ-chains gave a single precipitin line with the sea lion IgG but when made to react with dolphin serum produced two lines, suggesting the presence of two different subclasses of IgG in this species.
Resumo:
The evolution of a quantitative phenotype is often envisioned as a trait substitution sequence where mutant alleles repeatedly replace resident ones. In infinite populations, the invasion fitness of a mutant in this two-allele representation of the evolutionary process is used to characterize features about long-term phenotypic evolution, such as singular points, convergence stability (established from first-order effects of selection), branching points, and evolutionary stability (established from second-order effects of selection). Here, we try to characterize long-term phenotypic evolution in finite populations from this two-allele representation of the evolutionary process. We construct a stochastic model describing evolutionary dynamics at non-rare mutant allele frequency. We then derive stability conditions based on stationary average mutant frequencies in the presence of vanishing mutation rates. We find that the second-order stability condition obtained from second-order effects of selection is identical to convergence stability. Thus, in two-allele systems in finite populations, convergence stability is enough to characterize long-term evolution under the trait substitution sequence assumption. We perform individual-based simulations to confirm our analytic results.
Resumo:
BACKGROUND: Acute renal failure is a serious complication in critically ill patients and frequently requires renal replacement therapy, which alters trace element and vitamin metabolism. OBJECTIVE: The objective was to study trace element balances during continuous renal replacement therapy (CRRT) in intensive care patients. DESIGN: In a prospective randomized crossover trial, patients with acute renal failure received CRRT with either sodium bicarbonate (Bic) or sodium lactate (Lac) as a buffering agent over 2 consecutive 24-h periods. Copper, selenium, zinc, and thiamine were measured with highly sensitive analytic methods in plasma, replacement solutions, and effluent during 8-h periods. Balances were calculated as the difference between fluids administered and effluent losses and were compared with the recommended intakes (RI) from parenteral nutrition. RESULTS: Nineteen sessions were conducted in 11 patients aged 65 +/- 10 y. Baseline plasma concentrations of copper were normal, whereas those of selenium and zinc were below reference ranges; glutathione peroxidase was in the lower range of normal. The replacement solutions contained no detectable copper, 0.01 micromol Se/L (Bic and Lac), and 1.42 (Bic) and 0.85 (Lac) micromol Zn/L. Micronutrients were detectable in all effluents, and losses were stable in each patient; no significant differences were found between the Bic and Lac groups. The 24-h balances were negative for selenium (-0.97 micromol, or 2 times the daily RI), copper (-6.54 micromol, or 0.3 times the daily RI), and thiamine (-4.12 mg, or 1.5 times the RI) and modestly positive for zinc (20.7 micromol, or 0.2 times the RI). CONCLUSIONS: CRRT results in significant losses and negative balances of selenium, copper, and thiamine, which contribute to low plasma concentrations. Prolonged CRRT is likely to result in selenium and thiamine depletion despite supplementation at recommended amounts.
Resumo:
Circulating levels of adiponectin, a hormone produced predominantly by adipocytes, are highly heritable and are inversely associated with type 2 diabetes mellitus (T2D) and other metabolic traits. We conducted a meta-analysis of genome-wide association studies in 39,883 individuals of European ancestry to identify genes associated with metabolic disease. We identified 8 novel loci associated with adiponectin levels and confirmed 2 previously reported loci (P = 4.5×10(-8)-1.2×10(-43)). Using a novel method to combine data across ethnicities (N = 4,232 African Americans, N = 1,776 Asians, and N = 29,347 Europeans), we identified two additional novel loci. Expression analyses of 436 human adipocyte samples revealed that mRNA levels of 18 genes at candidate regions were associated with adiponectin concentrations after accounting for multiple testing (p<3×10(-4)). We next developed a multi-SNP genotypic risk score to test the association of adiponectin decreasing risk alleles on metabolic traits and diseases using consortia-level meta-analytic data. This risk score was associated with increased risk of T2D (p = 4.3×10(-3), n = 22,044), increased triglycerides (p = 2.6×10(-14), n = 93,440), increased waist-to-hip ratio (p = 1.8×10(-5), n = 77,167), increased glucose two hours post oral glucose tolerance testing (p = 4.4×10(-3), n = 15,234), increased fasting insulin (p = 0.015, n = 48,238), but with lower in HDL-cholesterol concentrations (p = 4.5×10(-13), n = 96,748) and decreased BMI (p = 1.4×10(-4), n = 121,335). These findings identify novel genetic determinants of adiponectin levels, which, taken together, influence risk of T2D and markers of insulin resistance.
Resumo:
SUMMARY: Large sets of data, such as expression profiles from many samples, require analytic tools to reduce their complexity. The Iterative Signature Algorithm (ISA) is a biclustering algorithm. It was designed to decompose a large set of data into so-called 'modules'. In the context of gene expression data, these modules consist of subsets of genes that exhibit a coherent expression profile only over a subset of microarray experiments. Genes and arrays may be attributed to multiple modules and the level of required coherence can be varied resulting in different 'resolutions' of the modular mapping. In this short note, we introduce two BioConductor software packages written in GNU R: The isa2 package includes an optimized implementation of the ISA and the eisa package provides a convenient interface to run the ISA, visualize its output and put the biclusters into biological context. Potential users of these packages are all R and BioConductor users dealing with tabular (e.g. gene expression) data. AVAILABILITY: http://www.unil.ch/cbg/ISA CONTACT: sven.bergmann@unil.ch
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BackgroundResearch indicates that the early attachment patterns of babies could influence their socio-emotional development and prevent the emergence of problematic behaviours in the child later in life. Many studies in the field of early attachment interventions have promoted a secure attachment bond between mother and infant. The purpose of this study was to evaluate the effectiveness of an early pilot intervention programme designed to promote a secure attachment bond in mother-infant dyads belonging to a population seeking regular treatment at urban health centres in Santiago, Chile.MethodsPrimipara mothers were randomly assigned to two intervention conditions: a secure attachment promotion programme (experimental group = 43) or an educational talk (control group = 29). The Strange Situation Assessment was used to collect data on the attachment patterns of babies.ResultsThe results show that after the intervention, there were more babies with secure attachment in the experimental group than in the control group.ConclusionsThese findings represent a preliminary step towards evaluating interventions aimed at promoting secure attachment in Chilean mother-child dyads. While the effect of the intervention is not significant, the effect size obtained is respectable and consistent with other meta-analytic findings.
Resumo:
Gene therapy approaches using recombinant adeno-associated virus serotype 2 (rAAV2) and serotype 8 (rAAV8) have achieved significant clinical benefits. The generation of rAAV Reference Standard Materials (RSM) is key to providing points of reference for particle titer, vector genome titer, and infectious titer for gene transfer vectors. Following the example of the rAAV2RSM, here we have generated and characterized a novel RSM based on rAAV serotype 8. The rAAV8RSM was produced using transient transfection, and the purification was based on density gradient ultracentrifugation. The rAAV8RSM was distributed for characterization along with standard assay protocols to 16 laboratories worldwide. Mean titers and 95% confidence intervals were determined for capsid particles (mean, 5.50×10(11) pt/ml; CI, 4.26×10(11) to 6.75×10(11) pt/ml), vector genomes (mean, 5.75×10(11) vg/ml; CI, 3.05×10(11) to 1.09×10(12) vg/ml), and infectious units (mean, 1.26×10(9) IU/ml; CI, 6.46×10(8) to 2.51×10(9) IU/ml). Notably, there was a significant degree of variation between institutions for each assay despite the relatively tight correlation of assay results within an institution. This outcome emphasizes the need to use RSMs to calibrate the titers of rAAV vectors in preclinical and clinical studies at a time when the field is maturing rapidly. The rAAV8RSM has been deposited at the American Type Culture Collection (VR-1816) and is available to the scientific community.
Resumo:
Résumé Cette thèse de doctorat se fixe comme objectif général de définir la spécificité d'un espace urbain situé en centre-ville à travers sa dynamique sociale et interethnique. Il s'agit de relever les différentes formes et manifestations ethniques, mais également de comprendre la manière dont est vécue cette socialité, tout en tenant compte du contexte urbain dans lequel elles se situent. La particularité de ce travail est le fait de proposer une démarche alliant deux disciplines à savoir la géographie et la sociologie, dans le but de proposer une recherche transdisciplinaire, avec comme conséquence la mise en oeuvre d'une démarche commune nourrie des deux disciplines. Les quartiers ethniques situés en centre-ville ne se présentent pas comme des espaces figés, puisque des changements fréquents sont observés aussi bien au niveau de leur population que de l'affectation des locaux commerciaux et des logements. Ils semblent davantage se caractériser comme des « espaces à l'avenir indéterminé » dans le sens où leur avenir aussi bien au niveau de leur structure urbaine que de leurs rapports sociaux ne peut être prévisible et qu'ils sont par ailleurs susceptibles d'être soumis à de nombreux changements, d'où l'idée également d' « espaces en mutations ». Pour aborder ces thématiques de recherche, nous avons opté pour une étude fondée sur le principe de la représentation et de l'une des formes essentielles à travers lesquelles elles se produisent et se manifestent, à savoir les images. Cette recherche privilégie ainsi une analyse dynamique du phénomène interethnique, l'inscrivant dans le courant constructiviste qui s'intéresse notamment à l'étude des pratiques des acteurs sociaux et leurs représentations, dans le sens qu'elles sont le fruit d'une construction sociale. Dans ce type de démarche analytique, il s'agit de prendre en considération à la fois l'analyse du chercheur et la réalité objective et subjective du vécu des acteurs urbains qui regroupent les riverains, les commerçants, les membres associatifs, les politiques et les médias. C'est justement l'association de ces deux approches qui permet de définir un quartier urbain. Abstract "The spatial and social stakes of an interethnic dynamics in transition in the downtown area. The construction of the various forms of representations in order to define an urban quarter in Nice" The general objective of this PHD is to define the specificity of an urban space located in the downtown area with social and interethnic dynamics. Specifically the diverse ethnic form and sign to include the understanding mariner where society has lived in a specific urban context. The particularity of this work is to advance an analytic method using two disciplines: geography and sociology, in order to bring up a transdisciplinarian research with a common method. The ethnic quarters in the inner-city area are not presented as fixed spaces, since frequent changes were observed in the population level and at the allotment level of the commercial premises and the lodgings. Defined as "undetermined future spaces" as their future in the urban structure or the social relations can not be foresee and are supposed to be subjective to many changes. Therefore speaking of "mutations spaces". The option of this type of thematic research is the study of the principle of representation and essential form which shows and produces the images. Research promotes a dynamic analyses of the interethnic phenomena, inside the constructivist which is focused the practices of social actors, their own representations, and products of a social construction. The production of analytical approach is necessary in order to consider the analyses of the research worker and the objective and subjective reality of the life of the urban actors. It gathers the residents, tradesmen, members of associations, politicians and the press. The association of these types of approach define a urban quarter.