972 resultados para Factor scores
Resumo:
Inflammation of the spinal cord after traumatic spinal cord injury leads to destruction of healthy tissue. This “secondary degeneration” is more damaging than the initial physical damage and is the major contributor to permanent loss of functions. In our previous study we showed that combined delivery of two growth factors, vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF), significantly reduced secondary degeneration after hemi-section injury of the spinal cord in the rat. Growth factor treatment reduced the size of the lesion cavity at 30d compared to control animals and further reduced the cavity at 90d in treated animals while in control animals the lesion cavity continued to increase in size. Growth factor treatment also reduced astrogliosis and reduced macroglia/macrophage activation around the injury site. Treatment with individual growth factors alone had similar effects to control treatments. The present study investigated whether growth factor treatment would improve locomotor behaviour after spinal contusion injury, a more relevant preclinical model of spinal cord injury. The growth factors were delivered for the first 7d to the injury site via osmotic minipump. Locomotor behaviour was monitored at 1-28d after injury using the BBB score and at 30d using automated gait analysis. Treated animals had BBB scores of 18; Control animals scored 10. Treated animals had significantly reduced lesion cavities and reduced macroglia/macrophage activation around the injury site. We conclude that growth factor treatment preserved spinal cord tissues after contusion injury, thereby allowing functional recovery. This treatment has the potential to significantly reduce the severity of human spinal cord injuries.
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Objective Research into youth caregiving in families where a parent experiences a significant medical condition has been hampered by a lack of contextually sensitive measures of the nature and breadth of young caregiving experiences. This study examined the factor structure and measurement invariance of such a measure called the Young Carer of Parents Inventory (YCOPI; Pakenham et al., 2006) using confirmatory factor analysis across 3 groups of youth. The YCOPI has 2 parts: YCOPI-A with 5 factors assessing caregiving experiences that are applicable to all caregiving contexts; YCOPI-B with 4 factors that tap dimensions related to youth caregiving in the context of parent illness. Design Two samples (ages 9–20 years) were recruited: a community sample of 2,429 youth from which 2 groups were derived (“healthy” family [HF], n = 1760; parental illness [PI], n = 446), and a sample of 130 youth of a parent with multiple sclerosis). Results With some modification, the YCOPI-A demonstrated a replicable factor structure across 3 groups, and exhibited only partial measurement invariance across the HF and PI groups. The impact of assuming full measurement invariance on latent mean differences appeared small, supporting use of the measure in research and applied settings when estimated using latent factors and controlling for measurement invariance. PI youth reported significantly higher scores than did HF youth on all YCOPI-A subscales. The YCOPI-B requires some modifications, and further development work is recommended. Conclusion The factor structure that emerged and the addition of new items constitutes the YCOPI-Revised. Findings support the use of the YCOPI-Revised in research and applied settings.
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Purpose Improved survival for men with prostate cancer has led to increased attention to factors influencing quality of life (QOL). As protein levels of vascular endothelial growth factor (VEGF) and insulin-like growth factor 1 (IGF-1) have been reported to be associated with QOL in people with cancer, we sought to identify whether single-nucleotide polymorphisms (SNPs) of these genes were associated with QOL in men with prostate cancer. Methods Multiple linear regression of two data sets (including approximately 750 men newly diagnosed with prostate cancer and 550 men from the general population) was used to investigate SNPs of VEGF and IGF-1 (10 SNPs in total) for associations with QOL (measured by the SF-36v2 health survey). Results Men with prostate cancer who carried the minor ‘T’ allele for IGF-1 SNP rs35767 had higher mean Role-Physical scale scores (≥0.3 SD) compared to non-carriers (p < 0.05). While this association was not identified in men from the general population, one IGF-1 SNP rs7965399 was associated with higher mean Bodily Pain scale scores in men from the general population that was not found in men with prostate cancer. Men from the general population who carried the rare ‘C’ allele had higher mean Bodily Pain scale scores (≥0.3 SD) than non-carriers (p < 0.05). Conclusions Through identifying SNPs that are associated with QOL in men with prostate cancer and men from the general population, this study adds to the mapping of complex interrelationships that influence QOL and suggests a role for IGF-I in physical QOL outcomes. Future research may identify biomarkers associated with increased risk of poor QOL that could assist in the provision of pre-emptive support for those identified at risk.
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Objectives. To determine whether genetic polymorphisms in or near the transforming growth factor β1 (TGFB1) locus were associated d with susceptibility to or severity of ankylosing spondylitis (AS). Methods. Five intragenic single-nucleotide polymorphisms (SNP) and three microsatellite markers flanking the TGFB1 locus were genotyped. Seven hundred and sixty-two individuals from 184 multiplex families were genotyped for the microsatellite markers and two of the promoter SNPs. One thousand and two individuals from 212 English and 170 Finnish families with AS were genotyped for all five intragenic SNPs. A structured questionnaire was used to assess the age of symptom onset, disease duration and disease severity scores, including the BASDAI (Bath Ankylosing Spondylitis Disease Activity Index) and BASFI (Bath Ankylosing Spondylitis Functional Index). Results. A weak association was noted between the rare TGFB1 + 1632 T allele and AS in the Finnish population (P = 0.04) and in the combined data set (P = 0.03). No association was noted between any other SNPs or SNP haplotype and AS, even among those families with positive non-parametric linkage scores. The TGFB1 +1632 polymorphism was also associated with a younger age of symptom onset (English population, allele 2 associated with age of onset greater by 4.2 yr, P = 0.05; combined data set, allele 2 associated with age of onset greater by 3.2 yr, P = 0.02). A haplotype of coding region SNPs (TGFB1 +869/ +915+1632 alleles 2/1/2) was associated with age of symptom onset in both the English parent-case trios and the combined data set (English data set, haplotype 2/1/2 associated with age of onset greater by 4.9 yr, P = 0.03; combined data set, haplotype 2/1/2 associated with greater age of onset by 4.2 yr, P = 0.006). Weak linkage with AS susceptibility was noted and the peak LOD score was 1.3 at distance 2 cM centromeric to the TGFB1 gene. No other linkage or association was found between quantitative traits and the markers. Conclusion. This study suggests that the polymorphisms within the TGFB1 gene play at most a small role in AS and that other genes encoded on chromosome 19 are involved in susceptibility to the disease.
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Background: Cognitive impairments are seen in first psychotic episode (FEP) patients. The neurobiological underpinnings that might underlie these changes remain unknown. The aim of this study is to investigate whether Brain Derived Neurotrophic Factor (BDNF) levels are associated with cognitive impairment in FEP patients compared with healthy controls. Methods: 45 FEP patients and 45 healthy controls matched by age, gender and educational level were selected from the Basque Country area of Spain. Plasma BDNF levels were assessed in healthy controls and in patients. A battery of cognitive tests was applied to both groups, with the patients being assessed at 6 months after the acute episode and only in those with a clinical response to treatment. Results: Plasma BDNF levels were altered in patients compared with the control group. In FEP patients, we observed a positive association between BDNF levels at six months and five cognitive domains (learning ability,immediate and delayed memory, abstract thinking and processing speed) which persisted after controlling for medications prescribed, drug use, intelligence quotient (IQ) and negative symptoms. In the healthy control group, BDNF levels were not associated with cognitive test scores. Conclusion: Our results suggest that BDNF is associated with the cognitive impairment seen after a FEP. Further investigations of the role of this neurotrophin in the symptoms associated with psychosis onset are warranted.
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Objective The aim of this study was to investigate the associations between alleles of the hypoxia-inducible factor 1A (HIF1A) C1772T polymorphism and several physiological responses to hypoxia, including the hypoxic ventilatory response (HVR), and serum erythropoietin (EPO), arterial oxygen saturation (Sao2), and acute mountain sickness (AMS) responses during 8 hours of exposure to normobaric hypoxia. Methods A total of 76 males participated in the study; 52 participants completed an 8-hour exposure to 12.7% oxygen, during which time Sao2, EPO concentrations, and AMS scores were measured, while 62 individuals took part in an HVR trial (in total 38 individuals completed both protocols). DNA was obtained from leukocytes, and a 346-bp fragment of the HIF1A gene containing the C1772T polymorphism was amplified using polymerase chain reaction. Fragments were sequenced to reveal individual genotypes, and the associations between HIF1A genotype and EPO, Sao2, AMS responses to hypoxia and HVR were examined. Results The magnitude of the hypoxic responses was highly variable between individuals. The increase in participants' EPO responses ranged from 89% to 388% of baseline values following hypoxia, while Sao2 values during the exposure ranged from 71% to 89%. The HVR ranged from −0.04 to +2.18 L · min−1 · Sao2%−1 among participants. No significant differences in EPO, Sao2, AMS, or HVR results were observed between the HIF1A CC genotype and the combined CT/TT genotype group. Conclusion In this study, the HIF1A C1772T polymorphism does not appear to influence EPO, Sao2, or AMS responses during acute hypoxic exposure, or the magnitude of the HVR.
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Cysteine proteinases have been implicated in astrocytoma invasion. We recently demonstrated that cathepsin S (CatS) expression is up-regulated in astrocytomas and provided evidence for a potential role in astrocytoma invasion (Flannery et al., Am J Path 2003;163(1):175–82). We aimed to evaluate the significance of CatS in human astrocytoma progression and as a prognostic marker. Frozen tissue homogenates from 71 patients with astrocytomas and 3 normal brain specimens were subjected to ELISA analyses. Immunohistochemical analysis of CatS expression was performed on 126 paraffin-embedded tumour samples. Fifty-one astrocytoma cases were suitable for both frozen tissue and paraffin tissue analysis. ELISA revealed minimal expression of CatS in normal brain homogenates. CatS expression was increased in grade IV tumours whereas astrocytoma grades I–III exhibited lower values. Immunohistochemical analysis revealed a similar pattern of expression. Moreover, high-CatS immunohistochemical scores in glioblastomas were associated with significantly shorter survival (10 vs. 5 months, p = 0.014). With forced inclusion of patient age, radiation dose and Karnofsky score in the Cox multivariate model, CatS score was found to be an independent predictor of survival. CatS expression in astrocytomas is associated with tumour progression and poor outcome in glioblastomas. CatS may serve as a useful prognostic indicator and potential target for anti-invasive therapy.
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The aim of this paper was to confirm the factor structure of the 20-item Beck Hopelessness Scale in a non-clinical population. Previous research has highlighted a lack of clarity in its construct validity with regards to this population.
Based on previous factor analytic findings from both clinical and non-clinical studies, 13 separate confirmatory factor models were specified and estimated using LISREL 8.72 to test the one, two and three-factor models.
Psychology and medical students at Queen's University, Belfast (n = 581) completed both the BHS and the Beck Depression Inventory (BDI).
All models showed reasonable fit, but only one, a four-item single-factor model demonstrated a nonsignificant chi-squared statistic. These four items can be used to derive a Short-Form BHS (SBHS) in which increasing scores (0-4) corresponded with increasing scores in the BDI. The four items were also drawn from all three of Beck's proposed triad, and included both positively and negatively scored items.
This study in a UK undergraduate non-clinical population suggests that the BHS best measures a one-factor model of hopelessness. It appears that a shorter four-item scale can also measure this one-factor model. (C) 2011 Elsevier Ltd. All rights reserved.
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Investigations of the factor structure of the Alcohol Use Disorders Identification Test (AUDIT) have produced conflicting results. The current study assessed the factor structure of the AUDIT for a group of Mentally Disordered Offenders (MDOs) and examined the pattern of scoring in specific subgroups. The sample comprised 2005 MDOs who completed a battery of tests including the AUDIT. Confirmatory factor analyses revealed that a two-factor solution – alcohol consumption and alcohol-related consequences – provided the best data fit for AUDIT scores. A three-factor solution provided an equally good fit, but the second and third factors were highly correlated and a measure of parsimony also favoured the two-factor solution. This study provides useful information on the factor structure of the AUDIT amongst a large MDO population, while also highlighting the difficulties associated with the presence of people with mental health problems in the criminal justice system.
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The Temporal Focus Scale (TFS) is a 12-item self-report measure of cognitive engagement with the temporal domains of past, present and future. Developed in college student samples, a three-factor structure with adequate reliability and validity was documented in a series of independent studies. We tested the factor structure of the scale in a sample of Northern Irish adolescents and found that our data supported a three factor structure, although there were problems with item 10. Because time perspective measures have been found to relate differentially to various health behaviours, we tested the relations between scores on the TFS and self-reported alcohol use. Results showed that scores on the TFS were not consistent statistical predictors of drinking category in a logistic regression. Results are discussed in terms of scale development, future scale use and the assessment of health-compromising behaviours such as adolescent alcohol consumption. © 2012 The Foundation for Professionals in Services for Adolescents.
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Acute lung injury is a common, devastating clinical syndrome associated with substantial mortality and morbidity with currently no proven therapeutic interventional strategy to improve patient outcomes. The objectives of this study are to test the potential therapeutic effects of keratinocyte growth factor for patients with acute lung injury on oxygenation and biological indicators of acute inflammation, lung epithelial and endothelial function, protease:antiprotease balance, and lung extracellular matrix degradation and turnover.
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The Behavioural Inhibition and Behavioural Activation System (BIS/BAS) scales were developed by Carver and White (1994) and comprise four scales which measure individual differences in personality (Gray 1982, 1991). More recent modifications, namely the five-factor model derived from Gray and McNaughton's (2000) revised Reward Sensitivity Theory (RST) suggests that Anxiety and Fear are separable components of inhibition. This study employed exploratory and confirmatory factor analyses on the scales in order to test whether the four or five-factor model was the better fit in a sample of 994 participants aged 11–30 years. Consistent with RST, superior model fit was shown for the five-factor model with all variables correlated. Significant age effects were observed for BIS Fear and BIS Anxiety, with scores peaking in middle and late adolescence respectively. The BAS subscales showed differential effects of age group. Significantly increasing scores from early to mid and from mid to late adolescence were found for Drive, but the effect of age on Fun Seeking and Reward Responsiveness was not significant.
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The contemporary literature investigating the construct broadly known as time perspective is replete with methodological and conceptual concerns. These concerns focus on the reliability and factorial validity of measurement tools, and the sample-specific modification of scales. These issues continue to hamper the development of this potentially useful psychological construct. An emerging body of evidence has supported the six-factor structure of scores on the Adolescent Time Inventory-Time Attitudes Scale, as well as their reliability. The present study utilized data from the first wave of a longitudinal study in the United Kingdom to examine the reliability, validity, and cross-cultural invariance of the scale. Results showed that the hypothesized six-factor model provided the best fit for the data; all alpha and omega estimates were >. .70; scores on ATI-TA factors related meaningfully to self-efficacy scores; and the factor structure was invariant across both research sites. Results are discussed in the context of the extant temporal literature.
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Much debate in schizotypal research has centred on the factor structure of the Schizotypal Personality Questionnaire (SPQ), with research variously showing higher-order dimensionality consisting of two to seven dimensions. In addition, cross-cultural support for the stability of those factors remains limited. Here, we examined the factor structure of the SPQ among British and Trinidadian adults. Participants from a White British sub-sample (n = 351) resident in the UK and from an African Caribbean sub-sample (n = 284) resident in Trinidad completed the SPQ. The higher-order factor structure of the SPQ was analysed through confirmatory factor analysis, followed by multiple-group analysis for the model of best-fit. Between-group differences for sex and ethnicity were investigated using multivariate analysis of variance in relation to the higher-order domains. The model of best-fit was the four-factor structure, which demonstrated measurement invariance across groups. Additionally, these data had an adequate fit for two alternative models: a) 3 factors and b) a modified 4-factor. The British sub-sample had significantly higher scores across all domains than the Trinidadian group, and men scored significantly higher on the disorganised domain than women. The four-factor structure received confirmatory support and, importantly, support for use with populations varying in ethnicity and culture.
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L’avancement en âge est associé à plusieurs modifications cognitives, dont un déclin des capacités à mémoriser et/ou à rappeler les événements vécus personnellement. Il amène parallèlement une augmentation des faux souvenirs, c.-à-d. le rappel d’événements qui ne se sont pas réellement déroulés. Les faux souvenirs peuvent avoir d’importantes répercussions dans la vie quotidienne des personnes âgées et il importe donc de mieux comprendre ce phénomène en vieillissement normal. Des études ont démontré l’importance de la fonction des lobes temporaux médians (FTM)/mémoire et de la fonction des lobes frontaux (FF)/fonctions exécutives dans l’effet de faux souvenirs. Ainsi, la première étude de la thèse visait à valider en français une version adaptée d’une méthode proposée par Glisky, Polster, & Routhieaux (1995), permettant de mesurer ces fonctions cognitives (Chapitre 2). L’analyse factorielle de cette étude démontre que les scores neuropsychologiques associés à la mémoire se regroupent en un facteur, le facteur FTM/mémoire, alors que ceux associés aux fonctions exécutives se regroupent en un deuxième facteur, le facteur FF/fonctions exécutives. Des analyses « bootstrap » effectuées avec 1 000 ré-échantillons démontrent la stabilité des résultats pour la majorité des scores. La deuxième étude de cette thèse visait à éclairer les mécanismes cognitifs (FTM/mémoire et FF/fonctions exécutives) ainsi que théoriques de l’effet de faux souvenirs accru en vieillissement normal (Chapitre 3). La Théorie des Traces Floues (TTF; Brainerd & Reyna, 1990) propose des explications de l’effet de faux souvenirs pour lesquelles la FTM/mémoire semble davantage importante, alors que celles proposées par la Théorie de l’Activation et du Monitorage (TAM; Roediger, Balota, & Watson, 2001) sont davantage reliées à la FF/fonctions exécutives. Les tests neuropsychologiques mesurant la FTM/mémoire ainsi que ceux mesurant la FF/fonctions exécutives ont été administrés à 52 participants âgés (moyenne de 67,81 ans). Basé sur l’étude de validation précédente, un score composite de la FTM/mémoire et un score composite de la FF/fonctions exécutives ont été calculés pour chaque participant. Ces derniers ont d’abord été séparés en deux sous-groupes, un premier au score FTM/mémoire élevé (n = 29, âge moyen de 67,45 ans) et un deuxième au score FTM/mémoire faible (n = 23, âge moyen de 68,26 ans) en s’assurant de contrôler statistiquement plusieurs variables, dont le score de la FF/fonctions exécutives. Enfin, ces participants ont été séparés en deux sous-groupes, un premier au score FF/fonctions exécutives élevé (n = 26, âge moyen 68,08 ans) et un deuxième au score FF/fonctions exécutives faible (n = 25, âge moyen de 67,36 ans), en contrôlant les variables confondantes, dont le score de la FTM/mémoire. Les proportions de vraie et de fausse mémoire (cibles et leurres associatifs) ont été mesurées à l’aide d’un paradigme Deese-Roediger et McDermott (DRM; Deese, 1959; Roediger & McDermott, 1995), avec rappel et reconnaissance jumelée à une procédure « Je me souviens / Je sais » (Tulving, 1985) chez les 52 participants âgés ainsi que chez 22 jeunes (âge moyen de 24,59 ans), apparié pour les années de scolarité. D’abord, afin de tester l’hypothèse de la TTF (Brainerd & Reyna, 1990), ces proportions ont été comparées entre les jeunes adultes et les deux sous-groupes de personnes âgées catégorisées selon le score de la FTM/mémoire. Ensuite, afin de tester l’hypothèse de la TAM (Roediger et al., 2001), ces proportions ont été comparées entre les jeunes adultes et les deux sous-groupes de personnes âgées catégorisées selon le score de la FF/fonctions exécutives. Il s’agit de la première étude qui compare directement ces hypothèses à travers de nombreuses mesures de vraie et de fausse mémoire. Les résultats démontrent que seule la FTM/mémoire modulait l’effet d’âge en vraie mémoire, et de manière quelque peu indirecte, en fausse mémoire et dans la relation entre la vraie et la fausse remémoration. Ensuite, les résultats démontrent que seule la FF/fonctions exécutives jouerait un rôle dans la fausse reconnaissance des leurres associatifs. Par ailleurs, en des effets d’âge sont présents en faux rappel et fausse remémorations de leurres associatifs, entre les jeunes adultes et les personnes âgées au fonctionnement cognitif élevé, peu importe la fonction cognitive étudiée. Ces résultats suggèrent que des facteurs autres que la FTM/mémoire et la FF/fonctions exécutives doivent être identifiés afin d’expliquer la vulnérabilité des personnes âgées aux faux souvenirs. Les résultats de cette thèse sont discutés à la lumière des hypothèses théoriques et cognitives en faux souvenirs (Chapitre 4).