909 resultados para Differential item functioning


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BACKGROUND: Cognitive deficits have been reported during the early stages of bipolar disorder; however, the role of medication on such deficits remains unclear. The aim of this study was to compare the effects of lithium and quetiapine monotherapy on cognitive performance in people following first episode mania. METHODS: The design was a single-blind, randomised controlled trial on a cohort of 61 participants following first episode mania. Participants received either lithium or quetiapine monotherapy as maintenance treatment over a 12-month follow-up period. The groups were compared on performance outcomes using an extensive cognitive assessment battery conducted at baseline, month 3 and month 12 follow-up time-points. RESULTS: There was a significant interaction between group and time in phonemic fluency at the 3-month and 12-month endpoints, reflecting greater improvements in performance in lithium-treated participants relative to quetiapine-treated participants. After controlling for multiple comparisons, there were no other significant interactions between group and time for other measures of cognition. CONCLUSION: Although the effects of lithium and quetiapine treatment were similar for most cognitive domains, the findings imply that early initiation of lithium treatment may benefit the trajectory of cognition, specifically verbal fluency in young people with bipolar disorder. Given that cognition is a major symptomatic domain of bipolar disorder and has substantive effects on general functioning, the ability to influence the trajectory of cognitive change is of considerable clinical importance.

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Spondylodiscitis represents 2%–4% of all bone infections cases. The correct diagnosis and appropriate treatment can prevent complications such as vertebral collapse and spinal cord compression, avoiding surgical procedures. The diagnosis is based on characteristic clinical and radiographic findings and confirmed by blood culture and biopsy of the disc or the vertebra. The present study was developed with Clementino Fraga Filho University Hospital patients with histopathologically and microbiologically confirmed diagnosis of spondylodiscitis, submitted to magnetic resonance imaging of the affected regions. In most cases, pyogenic spondylodiscitis affects the lumbar spine. The following findings are suggestive of the diagnosis: segmental involvement; ill-defined abscesses; early intervertebral disc involvement; homogeneous vertebral bodies and intervertebral discs involvement. Tuberculous spondylodiscitis affects preferentially the thoracic spine. Most suggestive signs include: presence of well-defined and thin-walled abscess; multisegmental, subligamentous involvement; heterogeneous involvement of vertebral bodies; and relative sparing of intervertebral discs. The present pictorial essay is aimed at showing the main magnetic resonance imaging findings of pyogenic and tuberculous discitis.

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BACKGROUND: A single overall rating of quality of life (QoL) is a sensitive method that is often used in population surveys. However, the exact meaning of response choices is unclear. In particular, uneven spacing may affect the way QoL ratings should be analyzed and interpreted. This study aimed to determine the intervals between response choices to a single-item QoL assessment. METHODS: A secondary analysis was conducted on data from the Lc65+ cohort study and two additional, population-based, stratified random samples of older people (N = 5,300). Overall QoL was rated as excellent, very good, good, fair or poor. A QoL score (range 0-100) was derived from participants' answers to a 28-item QoL assessment tool. A transformed QoL score ranging from 1 (poor) to 5 (excellent) was calculated. The same procedure was repeated to compute seven domain-specific QoL subscores (Feeling of safety; Health and mobility; Autonomy; Close entourage; Material resources; Esteem and recognition; Social and cultural life). RESULTS: Mean (95 % confidence intervals) QoL scores were 96.23 (95.81-96.65) for excellent, 93.09 (92.74-93.45) for very good, 81.45 (80.63-82.27) for good, 65.44 (62.67-68.20) for fair and 54.52 (45.31-63.73) for poor overall QoL, corresponding to transformed QoL scores of respectively 5.00, 4.70, 3.58, 2.05, and 1.00. Ordinality of the categories excellent to poor was preserved in all seven QoL subscores. CONCLUSIONS: The excellent-to-poor rating scale provides an ordinal measure of overall QoL. The intervals between response choices are unequal, but an interval scale can be obtained after adequate recoding of excellent, very good, good, fair and poor.

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Resistance to semi-dry environments has been considered a crucial trait for superior growth and survival of strains used for bioaugmentation in contaminated soils. In order to compare water stress programmes, we analyse differential gene expression among three phylogenetically different strains capable of aromatic compound degradation: Arthrobacter chlorophenolicus A6, Sphingomonas wittichii RW1 and Pseudomonas veronii 1YdBTEX2. Standardized laboratory-induced water stress was imposed by shock exposure of liquid cultures to water potential decrease, induced either by addition of solutes (NaCl, solute stress) or by addition of polyethylene glycol (matric stress), both at absolute similar stress magnitudes and at those causing approximately similar decrease of growth rates. Genome-wide differential gene expression was recorded by micro-array hybridizations. Growth of P. veronii 1YdBTEX2 was the most sensitive to water potential decrease, followed by S. wittichii RW1 and A. chlorophenolicus A6. The number of genes differentially expressed under decreasing water potential was lowest for A. chlorophenolicus A6, increasing with increasing magnitude of the stress, followed by S. wittichii RW1 and P. veronii 1YdBTEX2. Gene inspection and gene ontology analysis under stress conditions causing similar growth rate reduction indicated that common reactions among the three strains included diminished expression of flagellar motility and increased expression of compatible solutes (which were strain-specific). Furthermore, a set of common genes with ill-defined function was found between all strains, including ABC transporters and aldehyde dehydrogenases, which may constitute a core conserved response to water stress. The data further suggest that stronger reduction of growth rate of P. veronii 1YdBTEX2 under water stress may be an indirect result of the response demanding heavy NADPH investment, rather than the presence or absence of a suitable stress defence mechanism per se.

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Abstract Hyperechoic lesions are not a frequent finding at breasts ultrasonography, and most of times are associated with benign pathologies that do not require further evaluation. However, some neoplasms such as invasive breast carcinomas and metastases may present with hyperechogenicity. Thus, the knowledge about differential diagnoses and identification of signs of lesion aggressiveness are of great relevance to avoid unnecessary procedures or underdiagnosis, and to support the correct clinical/surgical approach. On the basis of such concepts, the present essay describes and illustrates the main features of hyperechoic lesions at breast ultrasonography in different cases, with anatomopathological correlation.

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Background: Being physically assaulted is known to increase the risk of the occurrence of post-traumatic stress disorder (PTSD) symptoms but it may also skew judgements about the intentions of other people. The objectives of the study were to assess paranoia and PTSD after an assault and to test whether theory-derived cognitive factors predicted the persistence of these problems. Method: At 4 weeks after hospital attendance due to an assault, 106 people were assessed on multiple symptom measures (including virtual reality) and cognitive factors from models of paranoia and PTSD. The symptom measures were repeated 3 and 6 months later. Results: Factor analysis indicated that paranoia and PTSD were distinct experiences, though positively correlated. At 4 weeks, 33% of participants met diagnostic criteria for PTSD, falling to 16% at follow-up. Of the group at the first assessment, 80% reported that since the assault they were excessively fearful of other people, which over time fell to 66%. Almost all the cognitive factors (including information-processing style during the trauma, mental defeat, qualities of unwanted memories, self-blame, negative thoughts about self, worry, safety behaviours, anomalous internal experiences and cognitive inflexibility) predicted later paranoia and PTSD, but there was little evidence of differential prediction. Conclusions: Paranoia after an assault may be common and distinguishable from PTSD but predicted by a strikingly similar range of factors.

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TCF7L2 is the susceptibility gene for Type 2 diabetes (T2D) with the largest effect on disease risk that has been discovered to date. However, the mechanisms by which TCF7L2 contributes to the disease remain largely elusive. In addition, epigenetic mechanisms, such as changes in DNA methylation patterns, might have a role in the pathophysiology of T2D. This study aimed to investigate the differences in terms of DNA methylation profile of TCF7L2 promoter gene between type 2 diabetic patients and age- and Body Mass Index (BMI)- matched controls. We included 93 type 2 diabetic patients that were recently diagnosed for T2D and exclusively on diet (without any pharmacological treatment). DNA was extracted from whole blood and DNA methylation was assessed using the Sequenom EpiTYPER system. Type 2 diabetic patients were more insulin resistant than their matched controls (mean HOMA IR 2.6 vs 1.8 in controls, P<0.001) and had a poorer beta-cell function (mean HOMA B 75.7 vs. 113.6 in controls, P<0.001). Results showed that 59% of the CpGs analyzed in TCF7L2 promoter had significant differences between type 2 diabetic patients and matched controls. In addition, fasting glucose, HOMA-B, HOMA-IR, total cholesterol and LDL-cholesterol correlated with methylation in specific CpG sites of TCF7L2 promoter. After adjustment by age, BMI, gender, physical inactivity, waist circumference, smoking status and diabetes status uniquely fasting glucose, total cholesterol and LDL-cholesterol remained significant. Taken together, newly diagnosed, drug-naïve type 2 diabetic patients display specific epigenetic changes at the TCF7L2 promoter as compared to age- and BMI-matched controls. Methylation in TCF7L2 promoter is further correlated with fasting glucose in peripheral blood DNA, which sheds new light on the role of epigenetic regulation of TCF7L2 in T2D.

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Fungi and bacteria are key agents in plant litter decomposition in freshwater ecosystems. However, the specific roles of these two groups and their interactions during the decomposition process are unclear. We compared the growth and patterns of degradativeenzymes expressed by communities of bacteria and fungi grown separately and in coexistence on Phragmites leaves. The two groups displayed both synergistic and antagonistic interactions. Bacteria grew better together with fungi than alone. In addition, there was a negative effect of bacteria on fungi, which appeared to be caused by suppression of fungal growth and biomass accrual rather than specifically affecting enzyme activity. Fungi growing alone had a high capacity for the decomposition of plant polymers such as lignin, cellulose, and hemicellulose. In contrast, enzyme activities were in general low when bacteria grew alone, and the activity of key enzymes in the degradation of lignin and cellulose (phenol oxidase and cellobiohydrolase) was undetectable in the bacteria-only treatment. Still, biomass-specific activities of most enzymes were higher in bacteria than in fungi. The low total activity and growth of bacteria in the absence of fungi in spite of apparent high enzymatic efficiency during the degradation of many substrates suggest that fungi provide the bacteria with resources that the bacteria were not able to acquire on their own, most probably intermediate decomposition products released by fungi that could be used by bacteria

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There is evidence that virtual reality (VR) pain distraction is effective at improving pain-related outcomes. However, more research is needed to investigate VR environments with other pain-related goals. The main aim of this study was to compare the differential effects of two VR environments on a set of pain-related and cognitive variables during a cold pressor experiment. One of these environments aimed to distract attention away from pain (VRD), whereas the other was designed to enhance pain control (VRC). Participants were 77 psychology students, who were randomly assigned to one of the following three conditions during the cold pressor experiment: (a) VRD, (b) VRC, or (c) Non-VR (control condition). Data were collected regarding both pain-related variables (intensity, tolerance, threshold, time perception, and pain sensitivity range) and cognitive variables (self-efficacy and catastrophizing). Results showed that in comparison with the control condition, the VRC intervention significantly increased pain tolerance, the pain sensitivity range, and the degree of time underestimation. It also increased self-efficacy in tolerating pain and led to a reduction in reported helplessness. The VRD intervention significantly increased the pain threshold and pain tolerance in comparison with the control condition, but it did not affect any of the cognitive variables. Overall, the intervention designed to enhance control seems to have a greater effect on the cognitive variables assessed. Although these results need to be replicated in further studies, the findings suggest that the VRC intervention has considerable potential in terms of increasing self-efficacy and modifying the negative thoughts that commonly accompany pain problems.

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Cells are constantly responding to signals from the surrounding tissues and the environment. To dispose of infected and potentially dangerous cells, to ensure the optimal execution of developmental processes and to maintain tissue homeostasis, a multicellular organism needs to tightly control both the number and the quality of its cells. Apoptosis is a form of active cellular self-destruction that enables an organism to regulate its cell number by deleting damaged or potentially dangerous cells. Apoptosis can be induced by death ligands, which bind to death receptors on the cell surface. Ligation of the receptors leads to the formation of an intracellular death inducing signaling complex (DISC). One of the DISC components is caspase-8, a protease that triggers the caspase cascade and is thereby a key initiator of programmed cell death. The activation of caspase-8 is controlled by the cellular FLICE-inhibitory proteins (c-FLIPs). Consequently, sensitivity towards receptor-mediated apoptosis is determined by the amount of c-FLIP, and the c-FLIP levels are actively regulated for example during erythroid differentiation of K562 erythroleukemia cells and by hyperthermia in Jurkat leukemia cells. The aim of my thesis was to investigate how c-FLIP is regulated during these processes. We found that c-FLIP isoforms are short-lived proteins, although c-FLIPS had an even shorter half-life than c-FLIPL. In both experimental models, increased death receptor sensitivity correlated with induced ubiquitylation and consequent proteasomal degradation of c-FLIP. Furthermore, we elucidated how phosphorylation regulates the biological functions and the turnover of c-FLIP, thereby contributing to death receptor sensitivity. We mapped the first phosphorylation sites on c-FLIP and dissected how their phosphorylation affects c-FLIP. Moreover, we demonstrated that phosphorylation of serine 193, a phosphorylated residue common to all c-FLIPs, is primarily mediated by the classical PKC. Furthermore, we discovered a novel connection between the phosphorylation and ubiquitylation of c-FLIP: phosphorylation of S193 protects c-FLIP from ubiquitylation. Surprisingly, although all c-FLIP isoforms are phosphorylated on this conserved residue, the biological outcome is different for the long and short isoforms, since S193 specifically prolongs the half-lives of the short c-FLIP isoforms, but not c-FLIPL. To summarize, we show that c-FLIP proteins are modified by ubiquitylation and phosphorylation, and that the biological outcomes of these modifications are isoform-specifically determined.

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This study compared the 7-item Personal Wellbeing Index (PWI) with two other versions which include the domains “Spirituality” and “Religion”, separately, in a sample of Brazilian (n = 1.047) and Chilean (n = 1.053) adolescents. A comparison of psychometric properties between the PWI versions was carried out through multigroup confi rmatory factor analysis showing adequate adjustments (CFI > .95, RMSEA < .08), whereas the item spirituality presented better performance. For the analysis of the differential contribution of each domain to the notion of global satisfaction, a regression on the item Overall Life Satisfaction (OLS) was applied using structural equations. It isrecommended the inclusion of the item spirituality in the original scale, considering the importance of such domain in both cultures

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Metaheuristic methods have become increasingly popular approaches in solving global optimization problems. From a practical viewpoint, it is often desirable to perform multimodal optimization which, enables the search of more than one optimal solution to the task at hand. Population-based metaheuristic methods offer a natural basis for multimodal optimization. The topic has received increasing interest especially in the evolutionary computation community. Several niching approaches have been suggested to allow multimodal optimization using evolutionary algorithms. Most global optimization approaches, including metaheuristics, contain global and local search phases. The requirement to locate several optima sets additional requirements for the design of algorithms to be effective in both respects in the context of multimodal optimization. In this thesis, several different multimodal optimization algorithms are studied in regard to how their implementation in the global and local search phases affect their performance in different problems. The study concentrates especially on variations of the Differential Evolution algorithm and their capabilities in multimodal optimization. To separate the global and local search search phases, three multimodal optimization algorithms are proposed, two of which hybridize the Differential Evolution with a local search method. As the theoretical background behind the operation of metaheuristics is not generally thoroughly understood, the research relies heavily on experimental studies in finding out the properties of different approaches. To achieve reliable experimental information, the experimental environment must be carefully chosen to contain appropriate and adequately varying problems. The available selection of multimodal test problems is, however, rather limited, and no general framework exists. As a part of this thesis, such a framework for generating tunable test functions for evaluating different methods of multimodal optimization experimentally is provided and used for testing the algorithms. The results demonstrate that an efficient local phase is essential for creating efficient multimodal optimization algorithms. Adding a suitable global phase has the potential to boost the performance significantly, but the weak local phase may invalidate the advantages gained from the global phase.

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On this instrumental study we intend to analyse the factorial structure of the Screen for Child Anxiety Related Emotional Disorders (SCARED) in a Spanish sample using exploratory and confirmatory factorial analysis. As a second objective we intend to develop a short form of it for rapid screening and, finally, to analyze the reliabilities of both questionnaires. The SCARED was administered to a community sample of 1,508 children aged between 8 and 12 years. The sample was randomly split using half for the exploratory analysis and the other half for the confirmatory study. Furthermore a reduced version of the SCARED was developed using the SchmidLeiman procedure. Exploratory Factor Analysis yielded a four factor structure comprised of Somatic/panic, Generalized anxiety, Separation anxiety and Social phobia factors This structure was confirmed using Confirmatory Factor Analysis. The four factors, the full scale and the short scale showed good reliabilities. The results obtained seem to indicate that the Spanish version of the SCARED has good internal consistency, and along with other recent results, has a structure of four related factors that replicates the dimensions proposed for anxiety disorders by the DSM-IV-TR