55 research outputs found

    Target Cueing Provides Support for Target- and Resource-Based Models of the Attentional Blink

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    The attentional blink (AB) describes a time-based deficit in processing the second of two masked targets. The AB is attenuated if successive targets appear between the first and final target, or if a cueing target is positioned before the final target. Using various speeds of stimulus presentation, the current study employed successive targets and cueing targets to confirm and extend an understanding of target-target cueing in the AB. In Experiment 1, three targets were presented sequentially at rates of 30 msec/item or 90 msec/item. Successive targets presented at 90 msec improved performance compared with non-successive targets. However, accuracy was equivalently high for successive and non-successive targets presented at 30 msec/item, suggesting that–regardless of whether they occurred consecutively–those items fell within the temporally defined attentional window initiated by the first target. Using four different presentation speeds, Experiment 2 confirmed the time-based definition of the AB and the success of target-cueing at 30 msec/item. This experiment additionally revealed that cueing was most effective when resources were not devoted to the cue, thereby implicating capacity limitations in the AB. Across both experiments, a novel order-error measure suggested that errors tend to decrease with an increasing duration between the targets, but also revealed that certain stimulus conditions result in stable order accuracy. Overall, the results are best encapsulated by target-based and resource-sharing theories of the AB, which collectively value the contributions of capacity limitations and optimizing transient attention in time

    Prognostic indices for brain metastases – usefulness and challenges

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    <p>Abstract</p> <p>Background</p> <p>This review addresses the strengths and weaknesses of 6 different prognostic indices, published since the Radiation Therapy Oncology Group (RTOG) developed and validated the widely used 3-tiered prognostic index known as recursive partitioning analysis (RPA) classes, i.e. between 1997 and 2008. In addition, other analyses of prognostic factors in groups of patients, which typically are underrepresented in large trials or databases, published in the same time period are reviewed.</p> <p>Methods</p> <p>Based on a systematic literature search, studies with more than 20 patients were included. The methods and results of prognostic factor analyses were extracted and compared. The authors discuss why current data suggest a need for a more refined index than RPA.</p> <p>Results</p> <p>So far, none of the indices has been derived from analyses of all potential prognostic factors. The 3 most recently published indices, including the RTOG's graded prognostic assessment (GPA), all expanded from the primary 3-tiered RPA system to a 4-tiered system. The authors' own data confirm the results of the RTOG GPA analysis and support further evaluation of this tool.</p> <p>Conclusion</p> <p>This review provides a basis for further refinement of the current prognostic indices by identifying open questions regarding, e.g., performance of the ideal index, evaluation of new candidate parameters, and separate analyses for different cancer types. Unusual primary tumors and their potential differences in biology or unique treatment approaches are not well represented in large pooled analyses.</p

    Prevalence and morphology of coronary artery ectasia with dual-source CT coronary angiography

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    To assess the prevalence and morphological characteristics of coronary artery ectasia (CAE) with CT coronary angiography (CTCA) in comparison to conventional catheterangiography (CCA). Dual-source CTCA examinations from 677 consecutive patients (223 women; median age 57 years) were retrospectively evaluated by two blinded observers for the presence of CAE defined as a diameter enlargement >/=1.5 times the diameter of adjacent normal coronary segments. Vessel diameters and contrast attenuation within and proximal to ectatic segments were measured. CCA was used to compare measurements obtained from CTCA with the coronary flow velocity by using the thrombolysis in myocardial infarction (TIMI) frame count. CTCA identified CAE in 20 of 677 (3%) patients. CCA was performed in ten of these patients. CAE diameter measurements with CTCA (10.0 +/- 5.4 mm) correlated significantly (r = 0.92, p < 0.001) with the CCA measurements (8.8 +/- 4.9 mm), but had higher diameters (levels of agreement: -1.0 to 3.4 mm). Contrast attenuation was significantly lower in the ectatic (343 +/- 63 HU) than in the proximal (394 +/- 60 HU) segments (p < 0.01). The attenuation difference significantly correlated with the CAE ratio (r = 0.67, p < 0.01) and the TIMI frame count (r = 0.58, p < 0.05). The prevalence of CAE in a population examined by CTCA is around 3%. Contrast attenuation measurements with CTCA correlate well with the flow alterations assessed with CCA

    Mucin expression in gastric- and gastro-oesophageal signet-ring cell cancer: results from a comprehensive literature review and a large cohort study of Caucasian and Asian gastric cancer

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    Background: The literature on the prognostic relevance of signet-ring cell (SRC) histology in gastric cancer (GC) is controversial which is most likely related to inconsistent SRC classification based on haematoxylin–eosin staining. We hypothesised that mucin stains can consistently identify SRC-GC and predict GC patient outcome. Methods: We performed a comprehensive literature review on mucin stains in SRC-GC and characterised the mucin expression in 851 Caucasian GC and 410 Asian GC using Alcian Blue (AB)-Periodic Acid-Schiff (PAS), MUC2 (intestinal-type mucin), and MUC5AC (gastric-type mucin). The relationship between mucin expression and histological phenotype [poorly cohesive (PC) including proportion of SRCs, non-poorly cohesive (non-PC), or mucinous (MC)], clinicopathological variables, and patient outcome was analysed. Results: Depending on mucin expression and cut-offs, the positivity rates of SRC-GC reported in the literature varied from 6 to 100%. Patients with MUC2 positive SRC-GC or SRC-GC with (gastro)intestinal phenotype had poorest outcome. In our cohort study, PC with ≥ 10% SRCs expressed more frequently MUC2, MUC5AC, and ABPAS (p < 0.001, p = 0.004 and p < 0.001, respectively). Caucasians with AB positive GC or combined ABPAS-MUC2 positive and MUC5AC negative had poorest outcome (all p = 0.002). This association was not seen in Asian patients. Conclusions: This is the first study to suggest that mucin stains do not help to differentiate between SRC-GC and non-SRC-GC. However, mucin stains appear to be able to identify GC patients with different outcome. To our surprise, the relationship between outcome and mucin expression seems to differ between Caucasian and Asian GC patients which warrants further investigations

    Increased frequency of familial Mediterranean fever in central Anatolia, Turkey

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    Objective. It has been observed that familial Mediterranean fever is more prevalent among people coming from central Anatolia in Turkey. To test this observation the frequency of FMF was investigated by afield survey in Sivas, a city located in central of Turkey
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