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Coimbra, Portugal

Pinto J.,Pediatric Hospital of Coimbra | Matos H.,Pediatric Hospital of Coimbra | Nobre S.,Pediatric Hospital of Coimbra | Marques M.,University of Coimbra | And 3 more authors.
Journal of Pediatric Gastroenterology and Nutrition

OBJECTIVES:: Fibrosis, related to several causes, can be diagnosed in children and adolescents' liver grafts that are >1 year old. At present, liver biopsy is the gold standard for assessing liver damage in the posttransplant setting. We aimed to evaluate the accuracy of noninvasive biomarkers of fibrosis, namely, acoustic radiation force impulse (ARFI), aspartate-to-platelet ratio index, and aspartate aminotransferase/alanine aminotransferase (AST/ALT) ratio index, either alone or in combination, for predicting fibrosis in pediatric patients submitted to liver transplantation. METHODS:: We prospectively assessed liver fibrosis in 30 children/adolescents with liver transplant through biopsy (liver transplant follow-up during 12 months). ARFI with Virtual Touch Software (Acuson 2000) was performed, and blood samples were taken to determine liver function and platelet count. Two groups were analyzed according to the histopathologic stage of fibrosis, namely, none/mild (F0-F1) versus significant fibrosis (F2-4). RESULTS:: The mean age of the 30 patients was 11 years (3-18 years), with a mean posttransplant period of assessment of 6.5 years. Twenty-four patients (80%) presented stage F0-F1 fibrosis and 6 patients (20%) presented stage F2-4. The area under the curve using receiver operating characteristic analysis for ARFI, aspartate-to-platelet ratio index, and AST/ALT ratio index for significant fibrosis was 0.76 (P = 0.052), 0.74 (P†Š= 0.066), and 0.69 (P =  0.162), respectively. Through multivariate logistic regression analysis, the only independent predictor of significant fibrosis was ARFI (odds ratio 10.7, 95% confidence interval 1.2-95.7; P =  0.045). The combination of ARFI and AST/ALT ratio index presented a good diagnostic accuracy of fibrosis (area under the curve of 0.83; P = 0.013). CONCLUSIONS:: ARFI may serve as a potential method for assessing significant fibrosis in pediatric patients with liver transplant, particularly in combination with AST/ALT ratio index. © 2014 by European Society. Source

Santos R.A.,Pediatric Hospital of Coimbra | Nogueira C.S.,University of Coimbra | Granja S.,Pediatric Hospital of Coimbra | Baptista J.B.,University of Coimbra | And 2 more authors.
Journal of Microbiology, Immunology and Infection

Kawasaki disease (KD) is an acute febrile multisystem vasculitic syndrome of unknown etiology, occurring mostly in infants and children younger than 5 years of age. We present a 13-month-old male with KD from whom was found human bocavirus DNA in nasopharyngeal secretions. Human bocavirus DNA in a patient with KD raised question about the coincidental or possible etiological association. © 2011. Source

Silva G.,A+ Network | Ribeiro M.J.,University of Coimbra | Costa G.N.,A+ Network | Costa G.N.,University of Coimbra | And 5 more authors.

The limited capacity of the human brain to process the full extent of visual information reaching the visual cortex requires the recruitment of mechanisms of information selection through attention. Neurofibromatosis type-1 (NF1) is a neurodevelopmental disease often exhibiting attentional deficits and learning disabilities, and is considered to model similar impairments common in other neurodevelopmental disorders such as autism. In a previous study, we found that patients with NF1 are more prone to miss targets under overt attention conditions. This finding was interpreted as a result of increased occipito-parietal alpha oscillations. In the present study, we used electroencephalography (EEG) to study alpha power modulations and the performance of patients with NF1 in a covert attention task. Covert attention was required in order to perceive changes (target offset) of a peripherally presented stimulus. Interestingly, alpha oscillations were found to undergo greater desynchronization under this task in the NF1 group compared with control subjects. A similar pattern of desynchronization was found for beta frequencies while no changes in gamma oscillations could be identified. These results are consistent with the notion that different attentional states and task demands generate different patterns of abnormal modulation of alpha oscillatory processes in NF1. Under covert attention conditions and while target offset was reported with relatively high accuracy (over 90%correct responses), excessive desynchronization was found. These findings suggest an abnormal modulation of oscillatory activity and attentional processes in NF1. Given the known role of alpha in modulating attention, we suggest that alpha patterns can show both abnormal increases and decreases that are task and performance dependent, in a way that enhanced alpha desynchronization may reflect a compensatory mechanism to keep performance at normal levels. These results suggest that dysregulation of alpha oscillations may occur in NF1 both in terms of excessive or diminished activation patterns. © 2016 Silva et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Source

Antunes S.G.,University of Coimbra | Silva J.S.,University of Coimbra | Santos J.B.,University of Coimbra | Martins P.,Pediatric Hospital of Coimbra | Castela E.,Pediatric Hospital of Coimbra
IEEE Transactions on Biomedical Engineering

Segmentation of echocardiographic images presents a great challenge because these images contain strong speckle noise and artifacts. Besides, most ultrasound segmentation methods are semiautomatic, requiring initial contour to be manually identified in the images. In this paper, we propose an algorithm based on the phase symmetry approach and level set evolution, in order to extract simultaneously all heart cavities in a fully automatic way. The level set evolution uses a new logarithmic-based stopping function, which demonstrates to perform well in the boundary extraction. We compared our method with other level set approaches, the watershed technique, and the manual segmentation made by two physicians. The experimental work was based on echocardiography images of children. Similarity metrics, namely Pratt function, pixel mean error, and similarity angle have been used for the performance evaluation of the different methods. The results indicate that our method has a performance of at least 4 superior to the other methods able to segment the four chambers. Even for the two worst boundary extraction cases (right ventricle and left atrium), the performance of the proposed method is still better than the other techniques. © 2011 IEEE. Source

Ribeiro M.J.,University of Coimbra | Violante I.R.,University of Coimbra | Ribeiro I.,University of Coimbra | Bernardino I.,University of Coimbra | And 6 more authors.
Investigative Ophthalmology and Visual Science

PURPOSE. Neurofibromatosis type 1 (NF1) is a monogenic disorder with the majority of patients presenting subtle to moderate cognitive impairments. Visuospatial deficits are considered to be one of the hallmark characteristics of their cognitive profile. However, low-level visual processing has not been previously investigated. Our aim was to study contrast perception in these patients to assess the function of early visual areas. METHODS. Contrast sensitivity was tested in 19 children and adolescents with NF1 and 33 control children and adolescents and 12 adults with NF1 and 24 control adults. The tasks used probed two achromatic spatiotemporal frequency channels and chromatic red-green and blue-yellow pathways. RESULTS. Individuals with NF1 showed significant contrast sensitivity deficits for the achromatic higher spatial frequency channel [F (1,83) = 36.1, P < 0.001] and for the achromatic low spatial high temporal (magnocellular) frequency channel [F (1,72) = 8.0, P < 0.01]. Furthermore, individuals with NF1 presented a significant deficit in chromatic red-green (parvocellular) contrast sensitivity (P < 0.01) but not in blue-yellow (koniocelular) sensitivity. The decrease in achromatic sensitivity for higher spatial frequency was observed throughout the visual field, in both central and peripheral locations. In contrast, central contrast sensitivity for the magnocellular-biased condition was relatively preserved and only peripheral sensitivity was affected. Interestingly, the same pattern of deficits was found in both age groups tested. CONCLUSIONS. These findings showed that contrast sensitivity is impaired in patients with NF1, associating for the first time abnormal low-level vision to the cognitive profile of this disorder. © 2012 The Association for Research in Vision and Ophthalmology, Inc. Source

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