123 research outputs found
Reversible cerebral vasoconstriction syndrome – A narrative revision of the literature
AbstractReversible Cerebral Vasoconstriction Syndrome (RCVS) is a not very well known clinical-imaging entity; it is characterized by thunderclap headache, which mimics an aneurysmal subarachnoid haemorrhage, and a diffuse and segmental constriction of cerebral arteries, that resolves spontaneously within 3 months. The pathophysiology remains unknown. The female gender is the more affected and more than half of cases occur in the puerperium or after exposure to vasoactive substances. Typically, RCVS is self-limited and has a benign course, although it may have more serious complications with permanent neurologic sequelae and death. Treatment is predominantly supportive and directed to the symptoms
Contributo para a validação do Adolescents/Adults Sensory Profile para a população portuguesa: consistência interna e temporal e validade do construto
Introdução: O Adolescents/ Adults Sensory Profile é um instrumento de avaliação da área da Terapia Ocupacional que visa avaliar a modulação sensorial de indivíduos a partir dos 11 anos de idade, através da análise dos seus padrões comportamentais. Objetivos: Analisar as propriedades psicométricas do Perfil Sensorial Adolescentes/ Adultos para a população portuguesa, tais como a consistência interna e temporal e validade do construto. Métodos: A amostra recolhida por conveniência foi constituída por 210 indivíduos entre os 11 e os 91 anos, que não apresentavam alterações da consciência. Para a análise da consistência temporal 30 dos sujeitos da amostra constituíram o grupo para o segundo momento de recolha de dados. A validade do construto foi avaliada através da análise fatorial confirmatória. Todos os dados foram tratados com recurso ao SPSS® 28.0 e ao Amos® 22. Resultados: A consistência interna obteve valores do Alpha de
Cronbach entre pobre e excelente para as secções e quadrantes (0,534<α<0,815), à exceção das secções do processamento do movimento (α=0,277) e do nível de atividade (α=0,373), onde foram obtidos valores inaceitáveis. A estabilidade teste-reteste variou entre alta e excelente (0,865<ICC<0,983) para as pontuações das secções e dos quadrantes e de considerável a excelente (0,371<Kappa<0,866) para a correlação entre itens. O erro padrão de medida variou entre 0,130 e 0,367, e foi sempre inferior ao desvio padrão das pontuações de cada secção e quadrante, revelando valores excelentes. Não foi possível confirmar a estrutura original do Adolescents/ Adults Sensory Profile porque a análise fatorial confirmatória obteve cinco medidas
com mau ajustamento: três para a estrutura fatorial de seis secções (CFI = 0,585, TLI = 0,564, PCFI = 0,557) e duas para a estrutura de quatro quadrantes (CFI = 0,667, TLI = 0,650). Na estrutura fatorial das seis secções foram encontrados 23 itens com coeficientes de saturação problemático e 14 itens na estrutura fatorial dos quatro quadrantes. Conclusão: O presente estudo demonstrou serem necessários estudos adicionais, com amostras de maior dimensão, para novo estudo das propriedades psicométricas e continuação do processo de validação do Perfil Sensorial Adolescentes/ Adultos para a população portuguesa
Classifying heart sounds using multiresolution time series motifs : an exploratory study
The aim of this work is to describe an exploratory study on the use of a SAX-based Multiresolution Motif Discovery method for Heart Sound Classification. The idea of our work is to discover relevant frequent motifs in the audio signals and use the discovered motifs and their frequency as characterizing attributes. We also describe different configurations of motif discovery for defining attributes and compare the use of a decision tree based algorithm with random forests on this kind of data. Experiments were performed with a dataset obtained from a clinic trial in hospitals using the digital stethoscope DigiScope. This exploratory study suggests that motifs contain valuable information that can be further exploited for Heart Sound Classification
Classifying heart sounds using SAX motifs, random forests and text mining techniques
In this paper we describe an approach to classifying heart sounds (classes Normal, Murmur and Extra-systole) that is based on the discretization of sound signals using the SAX (Symbolic Aggregate Approximation) representation. The ability of automatically classifying heart sounds or at least support human decision in this task is socially relevant to spread the reach of medical care using simple mobile devices or digital stethoscopes. In our approach, sounds are firrst pre-processed using signal processing techniques (decimate, low-pass filter, normalize, Shannon envelope). Then the pre-processed symbols are transformed into sequences of discrete SAX symbols. These sequences are subject to a process of motif discovery. Frequent sequences of symbols (motifs) are adopted as features. Each sound is then characterized by the frequent motifs that occur in it and their respective frequency. This is similar to the term frequency (TF) model used in text mining. In this paper we compare the TF model with the application of the TFIDF (Term frequency - Inverse Document Frequency) and the use of bi-grams (frequent size two sequences of motifs). Results show the ability of the motifs based TF approach to separate classes and the relative value of the TFIDF and the bi-grams variants. The separation of the Extra-systole class is overly dificult and much better results are obtained for separating the Murmur class. Empirical validation is conducted using
real data collected in noisy environments. We have also assessed the cost-reduction potential of the proposed methods by considering a fixed cost model and using a cost sensitive
meta algorithm.Portuguese Funds through the FCT - Fundacao para a Ciencia e a Tecnologia (proj. FCOMP-01-0124-FEDER-037281 and FCOMP-01-0124-FEDER-PEst-OE/EEI/UI0760/2014)
Psychophysical study of manual loads transportation - a comparative study between students and seasoned workers
The psychophysical criteria are important to develop manual material handling guidelines. It is essential that the studies that use a psychophysical approach be carried out as accurately as possible. However, the sample used in these studies can influence the results, if not appropriate. This work intends to analyze the influence of the sample in determining the maximum acceptable weight (MAW) in tasks of manual transport of loads transportation. The study involved 10 students and 10 workers. The participants’ task was to carry a box for 13 minutes and travel six meters. The box had the dimensions of 60 cm length × 40 cm width x 40 cm deep and the handles had 2.7 cm width and 9.0 cm in length. Moreover, subjects were required to carry out the movement of the box with the trunk erect and the forearms perpendicular to the body. In the end, the MAW and the rate of perceived exertion (RPE) were determined. A strength test was applied to each individual. The MAW was higher for students (11.6kg) than for workers (10.8kg), however, it was not verified significant differences between groups. For students, the MAW depended on the selected IW. Students also assigned RPE values higher than workers. These results suggest that the workers' experience may be a determining factor in the MAW. Although the study has not provided conclusive results, it can be argued that samples comprised by
students may affect the results, being that these groups of samples should be used with caution. So, whenever possible it should be used experienced workers in real work context for psychophysical studies.info:eu-repo/semantics/publishedVersio
Admission and Readmission/Death Patterns in Hospitalized and Non-hospitalized First-Ever-in-a-Lifetime Stroke Patients During the First Year: A Population-Based Incidence Study
Background: Hospitalization and readmission rates after a first-ever-in-a-lifetime stroke (FELS) are considered measures of quality of care and, importantly, may give valuable information to better allocate health-related resources. We aimed to investigate the hospitalization pattern and the unplanned readmissions or death of hospitalized (HospS) and non-hospitalized stroke (NHospS) patients 1 year after a FELS, based on a community register. Methods: Data about hospitalization and unplanned readmissions and case fatality 1 year after a FELS were retrieved from the population-based register undertaken in Northern Portugal (ACIN2), comprising all FELS in 2009-2011. We used the Kaplan-Meier method to estimate 1-year readmission/death-free survival and Cox proportional hazard models to identify independent factors for readmission/death. Results: Of the 720 FELS, 35.7% were not hospitalized. Unplanned readmission/death within 1 year occurred in 33.0 and 24.9% of HospS and NHospS patients, respectively. The leading causes of readmission were infections, recurrent stroke, and cardiovascular events. Stroke-related readmissions were observed in more than half of the patients in both groups. Male sex, age, pre- and post-stroke functional status, and diabetes were independent factors of readmission/death within 1 year. Conclusion: About one-third of stroke patients were not hospitalized, and the readmission/death rate was higher in HospS patients. Still, that readmission/death rate difference was likely due to other factors than hospitalization itself. Our research provides novel information that may help implement targeted health-related policies to reduce the burden of stroke and its complications.info:eu-repo/semantics/publishedVersio
A robust anisotropic edge detection method for carotid ultrasound image processing
The conference was held in Belgrade, Serbia, 3-5 September 2018.[Absctract]: A new approach for robust edge detection on B-mode ultrasound images of the carotid artery is proposed in this paper. The proposed method uses anisotropic Gaussian derivative filters along with non-maximum suppression over the overall artery wall orientation in local regions. The anisotropic filters allow using a wider integration scale along the edges while preserving the edge location precision. They also perform edge continuation, resulting in the connection of isolated edge points along linear segments, which is a valuable feature for the segmentation of the artery wall layers. However, this usually results in false edges being detected near convex contours and isolated points. The use of non-maximum suppression over pooled local orientations is proposed to solve this issue. Experimental results are provided to demonstrate that the proposed edge detector outperforms other common methods in the detection of the lumen-intima and media-adventia layer interfaces of the carotid vessel walls. Additionally, the resulting edges are more continuous and precisely located.This work is funded by the North Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL
2020 Partnership Agreement, and the European Regional Development Fund (ERDF), within the project
”NanoSTIMA: Macro-to-Nano Human Sensing: Towards Integrated Multimodal Health Monitoring and Analytics/NORTE-
01-0145-FEDER-000016”
Efficacy of Cerebral Autoregulation in Early Ischemic Stroke Predicts Smaller Infarcts and Better Outcome
© 2017 Castro, Serrador, Rocha, Sorond and Azevedo. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.Background and purpose: Effective cerebral autoregulation (CA) may protect the vulnerable ischemic penumbra from blood pressure fluctuations and minimize neurological
injury. We aimed to measure dynamic CA within 6 h of ischemic stroke (IS) symptoms
onset and to evaluate the relationship between CA, stroke volume, and neurological
outcome.
Methods: We enrolled 30 patients with acute middle cerebral artery IS. Within 6 h of
IS, we measured for 10 min arterial blood pressure (Finometer), cerebral blood flow
velocity (transcranial Doppler), and end-tidal-CO2. Transfer function analysis (coherence,
phase, and gain) assessed dynamic CA, and receiver-operating curves calculated relevant cut-off values. National Institute of Health Stroke Scale was measured at baseline.
Computed tomography at 24 h evaluated infarct volume. Modified Rankin Scale (MRS)
at 3 months evaluated the outcome.
Results: The odds of being independent at 3 months (MRS 0–2) was 14-fold higher when
6 h CA was intact (Phase > 37°) (adjusted OR = 14.0 (IC 95% 1.7–74.0), p = 0.013).
Similarly, infarct volume was significantly smaller with intact CA [median (range) 1.1
(0.2–7.0) vs 13.1 (1.3–110.5) ml, p = 0.002].
Conclusion: In this pilot study, early effective CA was associated with better neurological
outcome in patients with IS. Dynamic CA may carry significant prognostic implications.This study was part of Ph.D. thesis of PC and received publiC national grant from Fundação para a Ciência e a Tecnologia (FCT), Portugal, PTDC/SAU-ORG/113329/2009. FS is supported by R01 NS085002 (NINDS).info:eu-repo/semantics/publishedVersio
Cystatin F depletion in Mycobacterium tuberculosis-infected macrophages improves cathepsin C/granzyme B-driven cytotoxic effects on HIV-infected cells during coinfection
Cystatin F (CstF) is a protease inhibitor of cysteine cathepsins, including those involved in activating the perforin/granzyme cytotoxic pathways. It is targeted at the endolysosomal pathway but can also be secreted to the extracellular milieu or endocytosed by bystander cells. CstF was shown to be significantly increased in tuberculous pleurisy, and during HIV coinfection, pleural fluids display high viral loads. In human macrophages, our previous results revealed a strong upregulation of CstF in phagocytes activated by interferon γ or after infection with Mycobacterium tuberculosis (Mtb). CstF manipulation using RNA silencing led to increased proteolytic activity of lysosomal cathepsins, improving Mtb intracellular killing. In the present work, we investigate the impact of CstF depletion in macrophages during the coinfection of Mtb-infected phagocytes with lymphocytes infected with HIV. The results indicate that decreasing the CstF released by phagocytes increases the major pro-granzyme convertase cathepsin C of cytotoxic immune cells from peripheral blood-derived lymphocytes. Consequently, an observed augmentation of the granzyme B cytolytic activity leads to a significant reduction in viral replication in HIV-infected CD4+ T-lymphocytes. Ultimately, this knowledge can be crucial for developing new therapeutic approaches to control both pathogens based on manipulating CstF.info:eu-repo/semantics/publishedVersio
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