Comportamento motor do tronco e membro superior, num sistema de posicionamento rígido e dinâmico, durante atividade

A funcionalidade dos indivíduos com Paralisia Cerebral está muitas vezes comprometida devido às alterações do movimento e do controlo postural. Dadas estas alterações, a posição de sentado oferece uma maior estabilidade sendo muitas das atividades de vida diária desempenhadas nesta posição. O objetivo mais importante de intervenção é obter o máximo de funcionalidade na posição de sentado, particularmente do membro superior. Este objectivo, na maioria das vezes, só pode ser atingido com o uso de sistemas de posicionamento que tentam colmatar as alterações posturais e do movimento. Assim, o objetivo deste estudo de caso é verificar se existem diferenças no comportamento motor do tronco e do membro superior, com um sistema de posicionamento rígido e com um sistema de posicionamento dinâmico, numa jovem com Paralisia Cerebral, aquando da ativação manual de um switch. Foi realizado um estudo de caso único em que foi feita uma análise cinemática do movimento do tronco e membro superior na ativação de um switch BigMack, em três posições de teste com distâncias diferentes. Simultaneamente mediu-se a distribuição do peso durante o movimento, através do mapa de pressão e foi registada, bilateralmente a atividade dos músculos trapézio (porção média), longuíssimo, recto abdominal e oblíquo externo. Os resultados obtidos apontam, neste caso em particular, para uma melhoria na qualidade do movimento e da distribuição de peso, com o sistema de posicionamento dinâmico, sem diferenças entre os dois sistemas relativamente à ativação muscular.

Ressonância magnética funcional: mapeamento do córtex motor através do efeito BOLD

Introdução – A ressonância magnética funcional (RMf) é hoje uma ferramenta fundamental na investigação funcional do cérebro humano, quer em indivíduos saudáveis quer em doentes com patologias diversas. É uma técnica complexa que necessita de uma aplicação cuidada e rigorosa e uma compreensão dos mecanismos biofísicos, de modo a serem obtidos resultados fiáveis e com melhor aceitação clínica. O efeito BOLD (Blood Oxygenation Level Dependent), que se baseia nas propriedades magnéticas da hemoglobina, é o método mais utilizado para medir a atividade cerebral por RMf. Objetivos – Otimizar um protocolo de RMf por efeito BOLD em voluntários saudáveis para mapeamento do córtex motor, de modo a que possa ser aplicado no futuro em doentes com patologias diversas. Metodologia – Foram estudados 34 voluntários saudáveis divididos em 2 grupos de estudo: BOLD 1 e BOLD 2. Com vista à otimização, foram testados no subgrupo BOLD 1 diferentes paradigmas e no subgrupo BOLD 2 foi estudada a influência do tempo de eco (TE). Para as várias condições foram comparados os volumes da região ativada e os níveis de ativação obtidos. Resultados/Discussão – O córtex motor foi identificado em todos os voluntários estudados. Não foram detetadas diferenças estatisticamente significativas quando comparados os resultados obtidos com os diferentes parâmetros de aquisição. Conclusão – O protocolo foi otimizado tendo em conta o nível de conforto reportado pelos voluntários. Uma vez que se pretende aplicar este mesmo protocolo no estudo de doentes, este fator torna-se particularmente relevante.

Modelação e identificação de motor DC

O modelo matemático de um sistema real permite o conhecimento do seu comportamento dinâmico e é geralmente utilizado em problemas de engenharia. Por vezes os parâmetros utilizados pelo modelo são desconhecidos ou imprecisos. O envelhecimento e o desgaste do material são fatores a ter em conta pois podem causar alterações no comportamento do sistema real, podendo ser necessário efetuar uma nova estimação dos seus parâmetros. Para resolver este problema é utilizado o software desenvolvido pela empresa MathWorks, nomeadamente, o Matlab e o Simulink, em conjunto com a plataforma Arduíno cujo Hardware é open-source. A partir de dados obtidos do sistema real será aplicado um Ajuste de curvas (Curve Fitting) pelo Método dos Mínimos Quadrados de forma a aproximar o modelo simulado ao modelo do sistema real. O sistema desenvolvido permite a obtenção de novos valores dos parâmetros, de uma forma simples e eficaz, com vista a uma melhor aproximação do sistema real em estudo. A solução encontrada é validada com recurso a diferentes sinais de entrada aplicados ao sistema e os seus resultados comparados com os resultados do novo modelo obtido. O desempenho da solução encontrada é avaliado através do método das somas quadráticas dos erros entre resultados obtidos através de simulação e resultados obtidos experimentalmente do sistema real.

Lupus Myelopathy in a Child

A 5-year-old female developed, after a 7-month period of fever, anorexia, weight loss, and a transitory cutaneous erythematous eruption, a severe acute transverse myelopathy, with a partial recovery of motor and sensory function. She had positive antinuclear and antidouble-stranded DNA antibodies but no antiphospholipid antibodies. Six months later she had massive proteinuria and restarted treatment with steroids and cyclophosphamide. Our patient is one of the youngest reported with lupus myelopathy. We discuss the clinical presentation, the magnetic resonance imaging findings, and other relevant laboratory studies of this rare but serious complication of systemic lupus erythematosus.

Heat recovery from wastewater: numerical modelling of sewer systems

Dissertação para obtenção do Grau de Mestre em Engenharia do Ambiente, perfil Engenharia Sanitária

Atheroembolic Renal Disease As a Cause of Allograft Primary Non-Function

Atheroembolic renal disease, also referred to as cholesterol crystal embolization, is a rare cause of renal failure, secondary to occlusion of renal arteries, renal arterioles and glomerular capillaries with cholesterol crystals, originating from atheromatous plaques of the aorta and other major arteries. This disease can occur very rarely in kidney allografts in an early or a late clinical form. Renal biopsy seems to be a reliable diagnostic test and cholesterol clefts are the pathognomonic finding. However, the renal biopsy has some limitations as the typical lesion is focal and can be easily missed in a biopsy fragment. The clinical course of these patients varies from complete recovery of the renal function to permanent graft loss. Statins, acetylsalicyclic acid, and corticosteroids have been used to improve the prognosis. We report a case of primary allograft dysfunction caused by an early and massive atheroembolic renal disease. Distinctive histology is presented in several consecutive biopsies. We evaluated all the cases of our Unit and briefly reviewed the literature. Atheroembolic renal disease is a rare cause of allograft primary non -function but may become more prevalent as acceptance of aged donors and recipients for transplantation has become more frequent.

Exploring deregulated signals involved in motor neuron-microglia cross-talk in ALS

Part of the results discussed in this thesis was presented in the following meetings: Cunha MI, Cunha C, Vaz AR, Brites D. Studying microglial-motoneuron cross-talk in ALS pathology. 6th iMed.UL Postgraduate Students Meeting, Lisbon, July 2, 2014. [Abstract and Poster] Vaz AR. Motoneuron degeneration and glial reactivity in ALS: insights from cellular to animal models. Neuroscience Seminars at IMM 2012, Instituto de Medicina Molecular, Universidade de Lisboa, Lisbon, Portugal, June 9, 2014. [Oral Communication (by invitation)]

Learning joint representations for order and timing of perceptual-motor sequences: a dynamic neural field approach

Many of our everyday tasks require the control of the serial order and the timing of component actions. Using the dynamic neural field (DNF) framework, we address the learning of representations that support the performance of precisely time action sequences. In continuation of previous modeling work and robotics implementations, we ask specifically the question how feedback about executed actions might be used by the learning system to fine tune a joint memory representation of the ordinal and the temporal structure which has been initially acquired by observation. The perceptual memory is represented by a self-stabilized, multi-bump activity pattern of neurons encoding instances of a sensory event (e.g., color, position or pitch) which guides sequence learning. The strength of the population representation of each event is a function of elapsed time since sequence onset. We propose and test in simulations a simple learning rule that detects a mismatch between the expected and realized timing of events and adapts the activation strengths in order to compensate for the movement time needed to achieve the desired effect. The simulation results show that the effector-specific memory representation can be robustly recalled. We discuss the impact of the fast, activation-based learning that the DNF framework provides for robotics applications.

Stress-triggered synaptic malfunction: a gate along the path from depressionto dementia

Tese de Doutoramento em Ciências da Saúde.

Infarct Size as Predictor of Systolic Functional Recovery after Myocardial Infarction

Background: The effects of modern therapy on functional recovery after acute myocardial infarction (AMI) are unknown.Objectives:To evaluate the predictors of systolic functional recovery after anterior wall AMI in patients undergoing modern therapy (reperfusion, aggressive platelet antiaggregant therapy, angiotensin-converting enzyme inhibitors and beta-blockers).Methods:A total of 94 consecutive patients with AMI with ST-segment elevation were enrolled. Echocardiograms were performed during the in-hospital phase and after 6 months. Systolic dysfunction was defined as ejection fraction value < 50%.Results:In the initial echocardiogram, 64% of patients had systolic dysfunction. Patients with ventricular dysfunction had greater infarct size, assessed by the measurement of total and isoenzyme MB creatine kinase enzymes, than patients without dysfunction. Additionally, 24.5% of patients that initially had systolic dysfunction showed recovery within 6 months after AMI. Patients who recovered ventricular function had smaller infarct sizes, but larger values of ejection fraction and E-wave deceleration time than patients without recovery. At the multivariate analysis, it can be observed that infarct size was the only independent predictor of functional recovery after 6 months of AMI when adjusted for age, gender, ejection fraction and E-wave deceleration time.Conclusion: In spite of aggressive treatment, systolic ventricular dysfunction remains a frequent event after the anterior wall myocardial infarction. Additionally, 25% of patients show functional recovery. Finally, infarct size was the only significant predictor of functional recovery after six months of acute myocardial infarction.

Impact of Intensive Physiotherapy on Cognitive Function after Coronary Artery Bypass Graft Surgery

Background: Coronary artery bypass graft (CABG) is a standard surgical option for patients with diffuse and significant arterial plaque. This procedure, however, is not free of postoperative complications, especially pulmonary and cognitive disorders. Objective: This study aimed at comparing the impact of two different physiotherapy treatment approaches on pulmonary and cognitive function of patients undergoing CABG. Methods: Neuropsychological and pulmonary function tests were applied, prior to and following CABG, to 39 patients randomized into two groups as follows: Group 1 (control) - 20 patients underwent one physiotherapy session daily; and Group 2 (intensive physiotherapy) - 19 patients underwent three physiotherapy sessions daily during the recovery phase at the hospital. Non-paired and paired Student t tests were used to compare continuous variables. Variables without normal distribution were compared between groups by using Mann-Whitney test, and, within the same group at different times, by using Wilcoxon test. The chi-square test assessed differences of categorical variables. Statistical tests with a p value ≤ 0.05 were considered significant. Results: Changes in pulmonary function were not significantly different between the groups. However, while Group 2 patients showed no decline in their neurocognitive function, Group 1 patients showed a decline in their cognitive functions (P ≤ 0.01). Conclusion: Those results highlight the importance of physiotherapy after CABG and support the implementation of multiple sessions per day, providing patients with better psychosocial conditions and less morbidity.

Prognostication after cardiac arrest and hypothermia: a prospective study.

Current American Academy of Neurology (AAN) guidelines for outcome prediction in comatose survivors of cardiac arrest (CA) have been validated before the therapeutic hypothermia era (TH). We undertook this study to verify the prognostic value of clinical and electrophysiological variables in the TH setting. A total of 111 consecutive comatose survivors of CA treated with TH were prospectively studied over a 3-year period. Neurological examination, electroencephalography (EEG), and somatosensory evoked potentials (SSEP) were performed immediately after TH, at normothermia and off sedation. Neurological recovery was assessed at 3 to 6 months, using Cerebral Performance Categories (CPC). Three clinical variables, assessed within 72 hours after CA, showed higher false-positive mortality predictions as compared with the AAN guidelines: incomplete brainstem reflexes recovery (4% vs 0%), myoclonus (7% vs 0%), and absent motor response to pain (24% vs 0%). Furthermore, unreactive EEG background was incompatible with good long-term neurological recovery (CPC 1-2) and strongly associated with in-hospital mortality (adjusted odds ratio for death, 15.4; 95% confidence interval, 3.3-71.9). The presence of at least 2 independent predictors out of 4 (incomplete brainstem reflexes, myoclonus, unreactive EEG, and absent cortical SSEP) accurately predicted poor long-term neurological recovery (positive predictive value = 1.00); EEG reactivity significantly improved the prognostication. Our data show that TH may modify outcome prediction after CA, implying that some clinical features should be interpreted with more caution in this setting as compared with the AAN guidelines. EEG background reactivity is useful in determining the prognosis after CA treated with TH.

Post-traumatic mutism in children: clinical characteristics, pattern of recovery and clinicopathological correlations.

Among the numerous clinical syndromes observed after severe traumatic head injury, post-traumatic mutism is a disorder rarely reported in adults and not studied in any detail in children. We report seven children between the ages of 3 1/2 and 14 years who sustained severe head injury and developed post-traumatic mutism. We aim to give a precise clinical characterization of this disorder, discuss differential diagnosis and correlations with brain imaging and suggest its probable neurological substrate. After a coma lasting from 5 to 25 days, the seven patients who suffered from post-traumatic mutism went through a period of total absence of verbal production lasting from 5 to 94 days, associated with the recovery of non-verbal communication skills and emotional vocalization. During the first days after the recovery of speech, all patients were able to produce correct small sentences with a hypophonic and monotonous voice, moderate dysarthria, word finding difficulties but no signs of aphasia, and preserved oral comprehension. The neurological signs in the acute phase (III nerve paresis in three of seven patients, signs of autonomic dysfunctions in five of seven patients), the results of the brain imaging and the experimental animal data all suggest the involvement of mesencephalic structures as playing a key role in the aetiology of post-traumatic mutism.

Incoordination, Paralysis and Recovery after Pyrethroid Treatment on Nymphs III of Triatoma infestans (Hemiptera: Reduviidae)

Symptoms of poisoning for deltamethrin and cis-permethrin on nymphs III of Triatoma infestans were described. The time required for incoordination and paralysis were determined. Deltamethrin was equal or more rapid in the onset of the first effect (accordingly to dose), and cis-permethrin in the onset of the second one. There were no significant differences between incoordination doses 50% (IncD50s) at different times for the two pyrethroids. They showed equivalent incoordination power, but the nymphs treated with deltamethrin recovered slightly more rapid and in greater amount than the nymphs treated with cis-permethrin. The recovery was inhibited by the simultaneus application of piperonyl butoxide. This result suggests that biotransformation by mixed-function microsomal oxidases are involved in the process of recovery

Dietary fish oil is antihypertrophic but does not enhance postischemic myocardial function in female mice.

Clinically and experimentally, a case for omega-3 polyunsaturated fatty acid (PUFA) cardioprotection in females has not been clearly established. The goal of this study was to investigate whether dietary omega-3 PUFA supplementation could provide ischemic protection in female mice with an underlying genetic predisposition to cardiac hypertrophy. Mature female transgenic mice (TG) with cardiac-specific overexpression of angiotensinogen that develop normotensive cardiac hypertrophy and littermate wild-type (WT) mice were fed a fish oil-derived diet (FO) or PUFA-matched control diet (CTR) for 4 wk. Myocardial membrane lipids, ex vivo cardiac performance (intraventricular balloon) after global no-flow ischemia and reperfusion (15/30 min), and reperfusion arrhythmia incidence were assessed. FO diet suppressed cardiac growth by 5% and 10% in WT and TG, respectively (P < 0.001). The extent of mechanical recovery [rate-pressure product (RPP) = beats/min x mmHg] of FO-fed WT and TG hearts was similar (50 +/- 7% vs. 45 +/- 12%, 30 min reperfusion), and this was not significantly different from CTR-fed WT or TG. To evaluate whether systemic estrogen was masking a protective effect of the FO diet, the responses of ovariectomized (OVX) WT and TG mice to FO dietary intervention were assessed. The extent of mechanical recovery of FO-fed OVX WT and TG (RPP, 50 +/- 4% vs. 64 +/- 8%) was not enhanced compared with CTR-fed mice (RPP, 60 +/- 11% vs. 80 +/- 8%, P = 0.335). Dietary FO did not suppress the incidence of reperfusion arrhythmias in WT or TG hearts (ovary-intact mice or OVX). Our findings indicate a lack of cardioprotective effect of dietary FO in females, determined by assessment of mechanical and arrhythmic activity postischemia in a murine ex vivo heart model.