245 resultados para joint hypothesis tests


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Background and objectives Interleukin 18 (IL-18) is a pleiotropic cytokine involved in rheumatoid arthritis (RA) pathogenesis. This study was carried out to evaluate the effi cacy of IL-18 binding protein (IL-18BP) gene therapy in the rat adjuvant- induced arthritis (AIA) model and to decipher the mechanisms by which IL-18BP delivery lessens bone destruction.Materials and methods Arthritis was induced in female Lewis rat by Mycobacterium butyricum and the mRNA expression of IL-18 and IL-18BP was determined in the joints. In a preventive study, rats were divided into an adenovirus producing IL-18BP-Fc (AdmIL-18BP-Fc) group (n=8) and an adenovirus producing green fl uorescent protein (AdGFP) group (n=7). On day 8 after AIA induction, adenoviruses were injected. Clinical parameters were assessed. At day 18, during maximal arthritis, the rats were euthanized, ankles were collected and x-rays were performed. mRNA and protein were extracted from joints for analysis by quantitative reverse transcriptase-PCR, multiplex, Western blot and zymography.Results The authors observed a decrease in the (IL-18BP/ IL-18) ratio from day 7 to 45. Administration of AdmIL-18BPd-Fc decreased clinical parameters and prevented bone and joint destruction compared to AdGFP administration. IL-18BP delivery reduced the (receptor activator of nuclear factor κB ligand (RANKL)/osteoprotegerin (OPG)) ratio by 70%, the matrix metalloproteinase 9 (MMP9) level by 33% and the tartrate-resistant acid phosphatase (TRAP) level by 44% in the joint homogenates from AdmIL-18BPd-Fc compared to AdGFP treated rats.Conclusions In rat AIA, a decrease in the (IL-18BP/IL-18) ratio was observed. IL-18BP delivery prevented joint and bone destruction by downregulating MMP9, (RANKL/OPG) and TRAP, suggesting a potential benefi t of a similar therapy in RA.Abstract topics Towards novel therapeutic strategies.

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PURPOSE: To investigate the effect of intraocular straylight (IOS) induced by white opacity filters (WOF) on threshold measurements for stimuli employed in three perimeters: standard automated perimetry (SAP), pulsar perimetry (PP) and the Moorfields motion displacement test (MDT).¦METHODS: Four healthy young (24-28 years old) observers were tested six times with each perimeter, each time with one of five different WOFs and once without, inducing various levels of IOS (from 10% to 200%). An increase in IOS was measured with a straylight meter. The change in sensitivity from baseline was normalized, allowing comparison of standardized (z) scores (change divided by the SD of normative values) for each instrument.¦RESULTS: SAP and PP thresholds were significantly affected (P < 0.001) by moderate to large increases in IOS (50%-200%). The drop in motion displacement (MD) from baseline with WOF 5, was approximately 5 dB, in both SAP and PP which represents a clinically significant loss; in contrast the change in MD with MDT was on average 1 minute of arc, which is not likely to indicate a clinically significant loss.¦CONCLUSIONS: The Moorfields MDT is more robust to the effects of additional straylight in comparison with SAP or PP.

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Summary Throughout my thesis, I elaborate on how real and financing frictions affect corporate decision making under uncertainty, and I explore how firms time their investment and financing decisions given such frictions. While the macroeconomics literature has focused on the impact of real frictions on investment decisions assuming all equity financed firms, the financial economics literature has mainly focused on the study of financing frictions. My thesis therefore assesses the join interaction of real and financing frictions in firms' dynamic investment and financing decisions. My work provides a rationale for the documented poor empirical performance of neoclassical investment models based on the joint effect of real and financing frictions on investment. A major observation relies in how the infrequency of corporate decisions may affect standard empirical tests. My thesis suggests that the book to market sorts commonly used in the empirical asset pricing literature have economic content, as they control for the lumpiness in firms' optimal investment policies. My work also elaborates on the effects of asymmetric information and strategic interaction on firms' investment and financing decisions. I study how firms time their decision to raise public equity when outside investors lack information about their future investment prospects. I derive areal-options model that predicts either cold or hot markets for new stock issues conditional on adverse selection, and I provide a rational approach to study jointly the market timing of corporate decisions and announcement effects in stock returns. My doctoral dissertation therefore contributes to our understanding of how under real and financing frictions may bias standard empirical tests, elaborates on how adverse selection may induce hot and cold markets in new issues' markets, and suggests how the underlying economic behaviour of firms may induce alternative patterns in stock prices.

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Spondyloepimetaphyseal dysplasia with joint laxity, leptodactylic type (lepto-SEMDJL, aka SEMDJL, Hall type), is an autosomal dominant skeletal disorder that, in spite of being relatively common among skeletal dysplasias, has eluded molecular elucidation so far. We used whole-exome sequencing of five unrelated individuals with lepto-SEMDJL to identify mutations in KIF22 as the cause of this skeletal condition. Missense mutations affecting one of two adjacent amino acids in the motor domain of KIF22 were present in 20 familial cases from eight families and in 12 other sporadic cases. The skeletal and connective tissue phenotype produced by these specific mutations point to functions of KIF22 beyond those previously ascribed functions involving chromosome segregation. Although we have found Kif22 to be strongly upregulated at the growth plate, the precise pathogenetic mechanisms remain to be elucidated.

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A new method of measuring joint angle using a combination of accelerometers and gyroscopes is presented. The method proposes a minimal sensor configuration with one sensor module mounted on each segment. The model is based on estimating the acceleration of the joint center of rotation by placing a pair of virtual sensors on the adjacent segments at the center of rotation. In the proposed technique, joint angles are found without the need for integration, so absolute angles can be obtained which are free from any source of drift. The model considers anatomical aspects and is personalized for each subject prior to each measurement. The method was validated by measuring knee flexion-extension angles of eight subjects, walking at three different speeds, and comparing the results with a reference motion measurement system. The results are very close to those of the reference system presenting very small errors (rms = 1.3, mean = 0.2, SD = 1.1 deg) and excellent correlation coefficients (0.997). The algorithm is able to provide joint angles in real-time, and ready for use in gait analysis. Technically, the system is portable, easily mountable, and can be used for long term monitoring without hindrance to natural activities.

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BACKGROUND: Up to 10% of the patients in whom suspected betalactam hypersensitivity (HS) has been excluded by skin and challenge tests report suspected allergic reactions during subsequent treatments with the same or very similar betalactams. It has been suggested that the reactions may result from a resensitization induced by the challenge performed at the time of the allergological work-up. However, most patients did not undergo a second allergological work-up, to determine if the reactions resulted from betalactam HS or not. OBJECTIVES: We aimed to determine if children diagnosed nonallergic to betalactams have tolerated subsequent treatments with the initially suspected and/or other betalactams, and, in case of a reaction, if the reaction resulted from betalactam HS. Methods: We sent a questionnaire concerning the clinical history of their children to the parents of 256 children previously diagnosed nonallergic to betalactams. A second allergological work-up was performed in the children reporting suspected allergic reactions during subsequent treatments with the same and/or other betalactams. Skin tests were performed with the soluble form of the suspected (or very similar) betalactams and other betalactams from the same and other classes. Skin test responses were assessed at 15-20 min (immediate), 6-8 h (semi-late) and 48-72 h (late). Oral challenge (OC) was performed in children with negative skin tests, either at the hospital (immediate and accelerated reactions), or at home (delayed reactions). RESULTS: A response was obtained from 141 children (55.3%). Forty-eight (34%) of those children had not been treated with the betalactams for whom a diagnosis of allergy had been ruled out previously. Seven (7.5%) of the 93 children who had been treated again reported suspected allergic reactions. Skin tests and OC were performed in six of those children, and gave negative results in five children. In one child previously diagnosed nonallergic to amoxicillin associated with clavulanic acid, we diagnosed a delayed HS to clavulanic acid and a serum sickness-like disease to cefaclor. Thus, the frequency of reactions resulting from betalactam HS in children with negative skin and challenge tests is very low, and does not exceed 2.1% (2/93) if we consider that the child which refused a second allergological work-up is really allergic to betalactams. CONCLUSION: Our results in a very large number of children show that reactions presumed to result from betalactam HS are rare in children in whom the diagnosis of betalactam allergy has been ruled out previously. Moreover, they suggest that, as shown for the initial reactions, most of the reactions during subsequent treatments are rather a consequence of the infectious diseases for whom betalactams have been prescribed than a result of betalactam HS. Finally, they suggest that the risk of resensitization by OC is very low, and do not support the notion that skin testing should be repeated in children diagnosed nonallergic to betalactams.

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OBJECTIVES: To determine clinical and ultrasonographic predictors of joint replacement surgery across Europe in primary osteoarthritis (OA) of the knee. METHODS: This was a 3-year prospective study of a painful OA knee cohort (from a EULAR-sponsored, multicentre study). All subjects had clinical evaluation, radiographs and ultrasonography (US) at study entry. The rate of knee replacement surgery over the 3-year follow-up period was determined using Kaplan-Meier survival data analyses. Predictive factors for joint replacement were identified by univariate log-rank test then multivariate analysis using a Cox proportional-hazards regression model. Potential baseline predictors included demographic, clinical, radiographic and US features. RESULTS: Of the 600 original patients, 531 (88.5%), mean age 67+/-10 years, mean disease duration 6.1+/-6.9 years, had follow-up data and were analysed. During follow-up (median 3 years; range 0-4 years), knee replacement was done or required for 94 patients (estimated event rate of 17.7%). In the multivariate analysis, predictors of joint replacement were as follows: Kellgren and Lawrence radiographic grade (grade &gt; or =III vs &lt;III, hazards ratio (HR) = 4.08 (95% CI 2.34 to 7.12), p&lt;0.0001); ultrasonographic knee effusion (&gt; or =4 mm vs &lt;4 mm) (HR = 2.63 (95% CI 1.70 to 4.06), p&lt;0.0001); knee pain intensity on a 0-100 mm visual analogue scale (&gt; or =60 vs &lt;60) (HR = 1.81 (95% CI 1.15 to 2.83), p=0.01) and disease duration (&gt; or =5 years vs &lt;5 years) (HR=1.63 (95% CI 1.08 to 2.47), p=0.02). Clinically detected effusion and US synovitis were not associated with joint replacement in the univariate analysis. CONCLUSION: Longitudinal evaluation of this OA cohort demonstrated significant progression to joint replacement. In addition to severity of radiographic damage and pain, US-detected effusion was a predictor of subsequent joint replacement.

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Genetic polymorphisms have currently been described in more than 200 systems affecting pharmacological responses (cytochromes P450, conjugation enzymes, transporters, receptors, effectors of response, protection mechanisms, determinants of immunity). Pharmacogenetic testing, i.e. the profiling of individual patients for such variations, is about to become largely available. Recent progress in the pharmacogenetics of tamoxifen, oral anticoagulants and anti-HIV agents is reviewed to discuss critically their potential impact on prescription and contribution/limits for improving rational and safe use of pharmaceuticals. Prospective controlled trials are required to evaluate large-scale pharmacogenetic testing in therapeutics. Ethical, social and psychological issues deserve particular attention.

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Time-lapse geophysical monitoring and inversion are valuable tools in hydrogeology for monitoring changes in the subsurface due to natural and forced (tracer) dynamics. However, the resulting models may suffer from insufficient resolution, which leads to underestimated variability and poor mass recovery. Structural joint inversion using cross-gradient constraints can provide higher-resolution models compared with individual inversions and we present the first application to time-lapse data. The results from a synthetic and field vadose zone water tracer injection experiment show that joint 3-D time-lapse inversion of crosshole electrical resistance tomography (ERT) and ground penetrating radar (GPR) traveltime data significantly improve the imaged characteristics of the point injected plume, such as lateral spreading and center of mass, as well as the overall consistency between models. The joint inversion method appears to work well for cases when one hydrological state variable (in this case moisture content) controls the time-lapse response of both geophysical methods. Citation: Doetsch, J., N. Linde, and A. Binley (2010), Structural joint inversion of time-lapse crosshole ERT and GPR traveltime data, Geophys. Res. Lett., 37, L24404, doi: 10.1029/2010GL045482.

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Fat balance plays an important role in fat mass regulation. The mechanisms by which fat intake and fat oxidation are controlled are poorly understood. In particular, no data are available on the origin, i.e. exogenous (meal intake) or endogenous (adipose tissue lipolysis), of fat oxidized during the postprandial period in children and the proportion between these two components. In this study we tested the hypothesis that there is a relationship between adiposity and the oxidative fate of fat taken with a mixed meal in a group of 15 children with a wide range of fat mass (9-64%). The combination of stable isotope analysis ([13C] enriched fatty acids added to a mixed meal) and indirect calorimetry allowed us to differentiate between the exogenous and endogenous resting fat oxidation rate over the 9-h postprandial period. During the 9 hours of the postprandial period, the children oxidized an amount of fat comparable to that ingested with the meal [26.8 (+/-2.31) g vs. 26.4 (+/-2.3) g, respectively, P = ns]. On average, exogenous fat oxidation [2.99 (+/-3.0) g/9 h] represented 10.8% (+/-0.9) of total fat oxidation. Endogenous fat oxidation, calculated as the difference between total fat oxidation and exogenous fat oxidation, averaged 23.4 (+/-1.9) g/9 h and represented 88.2% (+/-0.9) of total fat oxidation. Endogenous fat oxidation as well as exogenous fat oxidation were highly correlated to total fat oxidation (r = 0.83, P < 0.001; r = 0.84, P < 0.001, respectively). Exogenous fat oxidation expressed as a proportion of total fat oxidation was directly related to fat mass (r = 0.56, P < 0.03), while endogenous fat oxidation expressed as a proportion of total fat oxidation was inversely related (r = -0.57, P < 0.03) to the degree of adiposity. The enhanced exogenous fat oxidation observed when adiposity increases in the dynamic phase of obesity may be viewed as a protective mechanism to prevent further increase in fat mass and hence to maintain fat oxidation at a sufficient rate when the body is exposed to a high amount of dietary fat, as typically encountered in obese children.

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BACKGROUND: Tuberculosis (TB) screening in prisons is recommended, but the appropriate methods remain controversial. Studies evaluating screening in remand prisons arc scarce. METHOD: Between 1997 and 2001, voluntary screening based on the tuberculin skin test (TST) was offered to all prisoners on entry into the largest remand prison in Switzerland. Prisoners with positive results underwent chest X-rays. We analysed this information collected in an anonymous database. RESULTS: A total of 4890 prisoners entered the prison and were eligible for screening; 3779 (77.3%) had TST performed on average 9 days after arrival: 46.9% were positive (induration >= 10 mm). Positive TST rates were similar over the 5 years. Women were more likely to have a negative TST (60.4%) than men (47.7%; P < 0.001, Pearson's chi(2) 16.5). Positive TSTs varied according to the prisoner's country of origin (64% for sub-Saharan Africa, 57% for Eastern Europe, 56% for North Africa, 51% for Asia and 34% for North and West Europe). CONCLUSION: The percentage of TST-positive subjects was high, and most did not receive preventive treatment for latent TB. The usefulness of systematic TST for all prisoners on entry is limited, as diagnosis of TB disease usually remains the priority in prisons. Keywords