Spatiotemporal mechanisms for actomyosin ring assembly and contraction in budding yeast cell division

Dissertation presented to obtain the Ph.D degree in Molecular Medicine

A contribuição da informática para o desenvolvimento sustentável: o exemplo do conceito de grid computing

Este trabalho foi realizado sob orientação do Prof. António Brandão Moniz para a disciplina “Factores Sociais da Inovação” do Mestrado Engenharia Informática realizado na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa (Portugal)

Anti-vibration gloves and the forearm efforts during tools operations

The objective of this paper is to analyze the forearm muscular contraction levels associated to the use of anti-vibration gloves, by comparing the contraction levels with gloves and without gloves. Two different vibration tools were used in a simulated work environment: (1) A compact Duty Multi-Cutter Bosch and (2) and a Percussion Drill with a drill bit Ø20 mm. Standard operations were performed by each subject in the following materials: (1) Performing cross- sectional cuts in 80x40 mm pine section and (2) performing 20 mm diameter holes in a concrete slab 2 x 2 m, 70 mm thick. The forearm contraction level were measured by surface electromyography in four different muscles: Flexor Digitorum Superficialis (FDS), Flexor Carpi Ulnaris (FCU), Extensor Carpi Radialis Longus (ECRL) e Extensor Carpi Ulnaris (ECU). For the flexor muscles (FDS, FCU), an increase tendency in muscular contraction was observed when the operations are performed without gloves (2-5% MVE increase in the FDS and 3-9% MVE increase in the FCU). For the extensor muscles ECU a decrease tendency in muscular contraction was observed when the operations are performed without gloves (1-10% MVE decrease). Any tendency was found in the ECRL muscle. ECU was the muscle with the highest contraction level for 79% and 71% of the operators, during the operations respectively with the multi-cutter (P50= 27-30%MVE) and with the percussion drill (P50=46-55%MVE). As a final conclusion from this study, anti- vibration gloves may increase the forearm fatigue in the posterior region of the forearm (ECU muscle) during operations with the mentioned tools

The friction force mouse-pad and the forearm muscles efforts (preliminary results)

The objective of the article is to evaluate the impact of the friction force mouse-pad in the contraction level of the forearm muscles M. extensor carpi ulnaris, M. extensor digitorum and M. extensor carpi radialis longus. A standard protocol of mouse movements was performed involving horizontal, vertical and diagonal mouse displacements drag-and-drop type. The operators were instructed to execute the protocol with their normal working speed. The movements protocol were performed by each subject (n=17) with three selected pairs mouse-pad, classified as low, medium and high friction force pairs. The mean time to execute the protocol with each mouse was ~138s. Mean values of ~13%MVE and ~17%MVE were found in the M. extensor carpi ulnaris and in the M. extensor digitorum respectively when performing the movements’ protocol. A 8.1% increase in %MVE was observed in the M. extensor digitorum and a 9.4% increase in %MVE was observed in the M. extensor carpi ulnaris when the high friction force pair was operated, relatively to the low friction force pair (p<0.05). The main preliminary conclusions of this study is that operating a high friction force mouse-pad may increase the risk to symptoms or disorders in the wrist due to an increase in the forearm muscles contraction levels, particularly during work with drawing application

Sarcoplasmic reticulum calcium ATPase is inhibited by organic vanadium coordination compounds: pyridine-2,6-dicarboxylatodioxovanadium(V), BMOV, and an amavadine analogue

Inorg Chem. 2008 Jul 7;47(13):5677-84. doi: 10.1021/ic702405d

Arte e poder na obra de Mário-Henrique Leiria

Dissertação apresentada para cumprimento dos requisitos necessários à obtenção do grau de Mestre em Estudos Portugueses

Psicopatologia obsessivo-compulsiva na distonia focal primária : aspectos neuropsiquiátricos de uma doença do movimento

RESUMO: pela contracção involuntária de grupos musculares de extensão variável, originando movimentos involuntários e posturas anómalas, por vezes dolorosas. O tratamento convencional consiste em injecções localizadas de toxina botulínica, podendo, em casos refractários, estar indicado o tratamento por estimulação cerebral profunda. A neurobiologia da distonia focal primária permanece incompletamente compreendida. Os estudos de neuro-imagem estrutural e funcional revelam alterações subtis da anatomia e funcionamento do estriado e das vias cortico-basais, com destaque para o aumento do volume, da actividade metabólica e da neuroplasticidade do putamen e de áreas corticais motoras, pré-motoras e sensitivas. O conjunto destas alterações aponta para uma disrupção da regulação inibitória de programas motores automáticos sustentados pelo estriado e pelas vias ortico-subcorticais. Nos últimos anos tem crescido o interesse pelas manifestações psiquiátricas e cognitivas da distonia (estas últimas muito pouco estudadas). Tem despertado particular interesse a possível associação entre distonia focal primária e perturbação obsessivo-compulsiva (POC), cuja neurobiologia parece notavelmente sobreponível à da distonia primária. Com efeito, os estudos de neuro-imagem estrutural e funcional na POC revelam consistentemente aumento do volume e actividade do estriado e do córtex órbito-frontal, apontando mais uma vez para uma disfunção do controlo inibitório, no estriado, de programas comportamentais e cognitivos automáticos. Objectivos: 1. Explorar a prevalência e intensidade de psicopatologia em geral, e de psicopatologia obsessivo-compulsiva em particular, numa amostra de indivíduos com distonia focal primária; 2. Explorar a ocorrência, natureza e intensidade de alterações do funcionamento cognitivo numa amostra de indivíduos com distonia focal primária; 3. Investigar a associação entre a gravidade da distonia focal, a intensidade da psicopatologia, e a intensidade das alterações cognitivas. Metodologia: Estudo de tipo transversal, caso-controlo, observacional e descritivo, com objectivos puramente exploratórios. Casos: 45 indivíduos com distonia focal primária (15 casos de blefaroespasmo, 15 de cãibra do escrivão, 15 de distonia cervical espasmódica), recrutados através da Associação Portuguesa de Distonia. Critérios de inclusão: idade = 18; distonia focal primária pura (excluindo casos de distonia psicogénica possível ou provável de acordo com os critérios de Fahn e Williams); Metabolismo do cobre e Ressonância Magnética Nuclear sem alterações. Controlos doentes: 46 casos consecutivos recrutados a partir da consulta externa do Hospital Egas Moniz: 15 doentes com espasmo hemifacial, 14 com espondilartropatia cervical, 17 com síndrome do canal cárpico. Controlos saudáveis: 30 voluntários. Critérios de exclusão para todos os grupos: Mini-Mental State Examination patológico, tratamento actual com anti-colinérgicos, antipsicóticos, inibidores selectivos da recaptação da serotonina, antidepressivos tri- ou tetracíclicos. Avaliação: Avaliação neurológica: história e exame médico e neurológico completos. Cotação da gravidade da distonia com a Unified Dystonia Rating Scale. Avaliação psicopatológica: Symptom Check-List-90-Revised; entrevista psiquiátrica de 60 minutos incluindo a Mini-International Neuropsychiatric Interview (MINI), versão 4.4 (validada em Português), complementada com os módulos da MINI Plus versão 5.0.0 para depressão ao longo da vida e dependência/ abuso do álcool e outras substâncias ao longo da vida; Yale-Brown Obsessive-Compulsive Symptom Checklist e a Yale-Brown Obsessive-Compulsive Scale (Y-BOCS). Avaliação neuropsicológica: Wisconsin Card Sorting Test (WCST; flexibilidade cognitiva); Teste de Stroop (inibição de resposta); Block Assembly Test (capacidade visuo-construtiva); Teste de Retenção Visual de Benton (memória de trabalho visuo-espacial). Análise estatística:os dados foram analisados com a aplicação informática SPSS for Windows, versão 13. Para a comparação de proporções utilizaram-se o teste do Chi-quadrado e o teste de Fisher. Para a comparação de variáveis quantitativas entre dois grupos utilizou-se o teste t de Student ou o teste U de Mann-Whitney (teste de Wilcoxon no caso de amostras emparelhadas). Para comparações de médias entre três grupos recorreu-se à Análise de Variância a um factor (variáveis de intervalo e de rácio), ou ao teste de Kruskal-Wallis (variáveis ordinais). Para o estudo da associação entre variáveis foram utilizados os coeficientes de correlação de Pearson ou de Spearman, a análise de correlações canónicas, a análise de trajectórias e a regressão logística. Adoptou-se um Alpha de 0.05. Resultados: Os doentes com distonia focal primária apresentaram uma pontuação média na Y- -BOCS significativamente superior à dos dois grupos de controlo. Em 24.4% dos doentes com distonia a pontuação na Y-BOCS foi superior a 16. Estes doentes eram predominantemente mulheres, tinham uma maior duração média da doença e referiam predominantemente sintomas obsessivo-compulsivos (SOC) de contaminação e lavagem. Os dois grupos com doença crónica apresentaram pontuações médias superiores às dos indivíduos saudáveis nas escalas de ansiedade, somatização e psicopatologia geral. Os doentes com distonia tratados com toxina botulínica apresentaram pontuações inferiores às dos doentes não tratados nas escalas de ansiedade generalizada, fobia, somatização e depressão, mas não na Y-BOCS. Sessenta por cento dos doentes com distonia apresentavam pelo menos um diagnóstico psiquiátrico actual ou pregresso. O risco de apresentar um diagnóstico psiquiátrico actual era menor nos doentes tratados com toxina botulínica, aumentando com a gravidade da doença. A prevalência de POC foi 8,3% e a de depressão major 37,7%. No WCST e na Prova de Benton, os doentes com distonia focal primária demonstraram um desempenho inferior ao de ambos os grupos de controlo, cometendo sobretudo erros perseverativos. Os doentes com distonia e pontuação na Y-BOCS > 16 cometeram mais erros e respostas perseverativas no WCST do que os restantes doentes com distonia. As análises de correlações e de trajectórias revelaram que nos doentes com distonia a gravidade da distonia foi, juntamente com a idade e a escolaridade, o factor que mais interagiu com o desempenho cognitivo. Discussão: o nosso estudo é o primeiro a descrever, nos mesmos doentes com distonia focal primária, SOC significativos e alterações cognitivas. Os nossos resultados confirmam a hipótese de uma associação clínica específica entre distonia focal primária e psicopatologia obsessivo-compulsiva. Confirmam igualmente que a distonia focal primária está associada a um maior risco de desenvolver morbilidade psiquiátrica ansiosa e depressiva. O tratamento com toxina botulínica reduz este risco, mas não influencia os SOC. Entre os doentes com distonia, os que têm SOC significativos poderão diconstituir um grupo particular com maior duração da doença (mas não uma maior gravidade), predomínio do sexo feminino e predomínio de SOC de contaminação e limpeza. Em termos cognitivos, os indivíduos com distonia focal primária apresentam défices significativos de flexibilidade cognitiva (particularmente acentuados nos doentes com SOC significativos) e de memória de trabalho visuo-espacial. Estes últimos devem-se essencialmente a um défice executivo e não a uma incapacidade visuo-construtiva ou visuo-perceptiva. A disfunção cognitiva não é explicável pela psicopatologia depressiva nem pela incapacidade motora, já que os controlos com doença periférica crónica tiveram um desempenho superior ao dos doentes com distonia. No seu conjunto os nossos resultados sugerem que os SOC que ocorrem na distonia focal primária constituem uma das manifestações clínicas da neurobiologia desta doença do movimento. O predomínio de sintomas relacionados com higiene e o perfil disexecutivo de alterações cognitivas–perseveração e dificuldades executivas de memória de trabalho visuo-espacial – apontam para a via cortico-basal dorso-lateral e para as áreas corticais que lhe estão associadas como estando implicadas na tripla associação entre sintomas motores, obsessivo-compulsivos e cognitivos. Conclusões: A distonia focal primária é um síndrome neuropsiquiátrico complexo com importantes manifestações não motoras, nomeadamente compromisso cognitivo do tipo disexecutivo e sintomas obsessivo-compulsivos. Clinicamente estas manifestações representam necessidades de tratamento que vão muito para além da simples incapacidade motora, devendo ser activamente exploradas e tratadas.-------------- ABSTRACT: Introduction: primary focal dystonia is an idiopathic movement disorder that manifests as involuntary, sustained contraction of muscular groups, leading to abnormal and often painful postures of the affected body part. Treatment is symptomatic, usually with local intramuscular injections of botulinum toxin. The neurobiology of primary focal dystonia remains unclear. Structural and functional neuroimaging studies have revealed subtle changes in striatal and cortical-basal pathway anatomy and function. The most consistent findings involve increased volume and metabolic activity of the putamen and of motor, pre-motor and somato-sensitive cortical areas. As a whole, these changes have been interpreted as reflecting a failure of striatal inhibitory control over automatic motor programs sustained by cortical-basal pathways. The last years have witnessed an increasing interest for the possible non-motor – mainly psychiatric and cognitive – manifestations of primary focal dystonia. The possible association of primary focal dystonia with obsessive-compulsive disorder (OCD) has raised particular interest. The neurobiology of the two disorders has indeed remarkable similarities: structural and functional neuroimaging studies in OCD have revealed increased volume and metabolic activity of the striatum and orbital-frontal cortex, again pointing to a disruption of inhibitory control of automatic cognitive and behavioural programs by the striatum. Objectives: 1. To explore the prevalence and severity of psychopathology – with a special emphasis on obsessive-compulsive symptoms (OCS) – in a sample of patients with primary focal dystonia;2. To explore the nature and severity of possible cognitive dysfunction in a sample of patients with primary focal dystonia; 3. To explore the possible association between dystonia severity, psychiatric symptom severity, and cognitive performance, in a sample of patients with primary focal dystonia. Methods: cross-sectional, case-control, descriptive study. Cases: forty-five consecutive, primary pure focal dystonia patients recruited from the Portuguese Dystonia Association case register (fifteen patients with blepharospasm, 15 with cervical dystonia and 15 with writer’s cramp). Inclusion criteria were: age = 18; primary pure focal, late-onset dystonia (excluding possible or probable psychogenic dystonia according to the Fahn & Williams criteria); normal copper metabolism and Magnetic Resonance Imaging. Diseased controls: forty-six consecutive subjects from our hospital case register (15 patients with hemi-facial spasm; 14 with cervical spondilarthropathy and cervical spinal root compression; 17 with carpal tunnel syndrome). Healthy controls were 30 volunteers.Exclusion criteria for all groups: Mini-Mental State Examination score below the validated cut-off for the Portuguese population (<23 for education between 1 and 11 years; <28 for education >11 years); use of anti-cholinergics, neuroleptics, selective serotonin reuptake inhibitors, triciclic or tetraciclic antidepressants. Assessment: neurological assessment: complete medical and neurological history and physical examination; dystonia severity scoring with the Unified Dystonia Rating Scale. Psychiatric assessment:Symptom Check-List-90-Revised; 60 minute-long psychiatric interview, including Mini-International Neuropsychiatric Interview (MINI), version 4.4 (validated Portuguese version), extended with the sections for life-time major depressive disorder and life-time alcohol and substance abuse disorder from MINI-Plus version 5.0.0; Yale-Brown Obsessive-Compulsive Symptom Checklist and Yale-Brown Obsessive-Compulsive Scale (Y-BOCS). Cognitive assessment: Wisconsin Card Sorting Test (WCST; cognitive set-shifting ability); Stroop Test (response inhibition); Block Assembly Test(visual-constructive ability); Benton’s Visual Retention Test (visual-spatial working memory). Statistic analysis: Data were analyzed with SPSS for Windows version 13. Proportions were compared using Chi-Square test, or Fisher’s exact test when appropriate. Student’s t-test or Mann-Whitney’s U test (or Wilcoxon’s teste in the case of matched samples) were used for two-group comparisons. P-values were corrected for multiple comparisons. One-way ANOVA with Bonferroni post-hoc analysis (interval data), or the Kruskal-Wallis Test (ordinal data), were used for three-group comparisons. Associations were analysed with Pearson’s or Spearman’s correlation coefficients, canonical correlations, path analysis and logistic regression analysis. Alpha was set at 0.05. Results: Dystonia patients had higher Yale-Brown Obsessive-Compulsive Symptom scores than both control groups. 24.4% of primary dystonia patients had a Y-BOCS score > 16. These patients were predominantly women; they had longer disease duration, and showed a predominance of hygiene-related OCS. The two groups with chronic disease had higher anxiety, somatization and global psychopathology scores than healthy subjects. Primary dystonia patients undergoing treatment with botulinum toxin had lower anxiety, phobia, somatization and depression scores than their untreated counterparts, but similar Y-BOCS scores. Sixty percent of primary dystonia patients had at least one lifetime psychiatric diagnosis. The odds of having a currently active psychiatric diagnosis were lower in botulinum toxin treated patients, and increased with dystonia severity. The prevalence of OCD was 6.7%, and the lifetime prevalence of major depression was 37.7%. Primary dystonia patients had a lower performance than the two control groups in both the WCST and Benton’s Visual Retention Test, mainly due to an excess of perseveration errors. Primary dystonia patients with Y-BOCS score > 16 had much higher perseveration error and perseveration response scores than dystonia patients with Y-BOCS = 16. Correlation and path analysis showed that, in the primary dystonia group, dystonia severity, along with age and education, was the main factor influencing cognitive performance. Discussion: our study is the first description ever of concomitant significant OCS and cognitive impairment in primary dystonia patients. Our results confirm that primary dystonia is specifically associated with obsessive-compulsive psychopathology. They also confirm that primary focal dystonia patients are at a higher risk of developing anxious and depressive psychiatric morbidity. Treatment with botulinum toxin decreases this risk, but does not influence OCS. Primary focal dystonia patients with significant OCS may constitute a particular subgroup. They are predominantly women, with higher disease duration (but not severity) and a predominance of hygiene related OCS.In terms of cognitive performance, primary focal dystonia patients have significant deficits involving set-shifting ability and visual-spatial working memory. The latter result from an essentially executive deficit, rather than from a primary visual-constructive apraxia or perceptual deficit. Furthermore, cognitive flexibility difficulties were more prominent in the subset of primary dystonia patients with significant OCS. The cognitive dysfunction found in dystonia patients is not attributable to depressive psychopathology or motor disability, as their performance was significantly lower than that of similarly impaired diseased controls. Our results suggest that OCS in primary focal dystonia are a direct, primary manifestation of the motor disorder’s neurobiology. The predominance of hygiene-related symptoms and the disexecutive pattern of cognitive impairment – set-shifting and visual-spatial working memory deficits – suggest that the dorsal-lateral cortical-basal pathway may play a decisive role in the triple association of motor dysfunction, OCS and cognitive impairment. Conclusions: primary focal dystonia is a complex neuropsychiatric syndrome with significant non- -motor manifestations, namely cognitive executive deficits and obsessive-compulsive symptoms.Clinically, our results show that PFD patients may have needs for care that extend far beyond a merely motor disability and must be actively searched for and treated.

Coherence and phase locking disruption in electromyograms of patients with amyotrophic lateral sclerosis

Dissertação para obtenção do Grau de Mestre em Engenharia Biomédica

Study of the electromyographic signal dynamic behavior in Amyotrophic Lateral Sclerosis (ALS)

Amyotrophic Lateral Sclerosis (ALS) is a neurodegenerative disease characterized by motor neurons degeneration, which reduces muscular force, being very difficult to diagnose. Mathematical methods are used in order to analyze the surface electromiographic signal’s dynamic behavior (Fractal Dimension (FD) and Multiscale Entropy (MSE)), evaluate different muscle group’s synchronization (Coherence and Phase Locking Factor (PLF)) and to evaluate the signal’s complexity (Lempel-Ziv (LZ) techniques and Detrended Fluctuation Analysis (DFA)). Surface electromiographic signal acquisitions were performed in upper limb muscles, being the analysis executed for instants of contraction for ipsilateral acquisitions for patients and control groups. Results from LZ, DFA and MSE analysis present capability to distinguish between the patient group and the control group, whereas coherence, PLF and FD algorithms present results very similar for both groups. LZ, DFA and MSE algorithms appear then to be a good measure of corticospinal pathways integrity. A classification algorithm was applied to the results in combination with extracted features from the surface electromiographic signal, with an accuracy percentage higher than 70% for 118 combinations for at least one classifier. The classification results demonstrate capability to distinguish members between patients and control groups. These results can demonstrate a major importance in the disease diagnose, once surface electromyography (sEMG) may be used as an auxiliary diagnose method.

Modulation of electrical stimulation applied to human physiology and clinical diagnostic

The use, manipulation and application of electrical currents, as a controlled interference mechanism in the human body system, is currently a strong source of motivation to researchers in areas such as clinical, sports, neuroscience, amongst others. In electrical stimulation (ES), the current applied to tissue is traditionally controlled concerning stimulation amplitude, frequency and pulse-width. The main drawbacks of the transcutaneous ES are the rapid fatigue induction and the high discomfort induced by the non-selective activation of nervous fibers. There are, however, electrophysiological parameters whose response, like the response to different stimulation waveforms, polarity or a personalized charge control, is still unknown. The study of the following questions is of great importance: What is the physiological effect of the electric pulse parametrization concerning charge, waveform and polarity? Does the effect change with the clinical condition of the subjects? The parametrization influence on muscle recruitment can retard fatigue onset? Can parametrization enable fiber selectivity, optimizing the motor fibers recruitment rather than the nervous fibers, reducing contraction discomfort? Current hardware solutions lack flexibility at the level of stimulation control and physiological response assessment. To answer these questions, a miniaturized, portable and wireless controlled device with ES functions and full integration with a generic biosignals acquisition platform has been created. Hardware was also developed to provide complete freedom for controlling the applied current with respect to the waveform, polarity, frequency, amplitude, pulse-width and duration. The impact of the methodologies developed is successfully applied and evaluated in the contexts of fundamental electrophysiology, psycho-motor rehabilitation and neuromuscular disorders diagnosis. This PhD project was carried out in the Physics Department of Faculty of Sciences and Technology (FCT-UNL), in straight collaboration with PLUX - Wireless Biosignals S.A. company and co-funded by the Foundation for Science and Technology.