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Neuropsychological Function in Relation to Structural and Functional Brain Changes in Alzheimer’s DiseaseElgh, Eva January 2004 (has links)
The aim of this doctoral thesis was to study neuropsychological function in relation to structural and functional brain changes in Alzheimer´s disease (AD). In the first study relations between hippocampal volume, neuropsychological function and limbic-hypothalamic-pituitary-adrenal (LHPA) axis disturbances in AD were investigated with magnetic resonance imaging (MRI). Reduced hippocampal CA1 volume and suppressed cortisol levels in combination, best predicted the variation in neuropsychological performance. The conclusion was that reduced hippocampal volume and LHPA axis disturbances are associated to level of cognitive function in AD. The second study focused on whether patients with early AD showed an altered regional cerebral blood flow (rCBF) pattern compared to control persons, correlation between performance on memory tests and rCBF in sub-lobar volumes of the brain were investigated. The rCBF was measured with single photon emission computed tomography (SPECT). AD-patients showed a significantly lower rCBF in temporoparietal regions including left hippocampus compared to controls. The diagnostic sensitivity and specificity for AD was high in temporoparietal regions. AD-patients had significantly lower performance on semantic and, in particular, episodic memory-tests compared to the controls, and their performance on several episodic tests correlated with rCBF in parietal and temporal regions including left hippocampus, which suggest that abnormalities in the rCBF pattern underlie impaired episodic memory functioning in AD. The conclusion was that an observer-independent analyzing method for SPECT with sub-lobar volumes VOI´s is promising in the diagnosis of AD. In a third study possible differences in memory-related functional brain activation between persons with high versus low risk for AD were examined with functional magnetic resonance imaging (fMRI). The high-risk individuals performed worse than low-risk individuals on tests of episodic memory. Patterns of brain activity during episodic encoding and retrieval showed significant group differences. During both encoding and retrieval, the low-risk persons showed increased activity relative to a baseline condition in prefrontal and hippocampal brain regions that previously have been implicated in episodic memory. By contrast, the high-risk persons did not significantly activate any prefrontal regions, but instead showed increased activity in visual occipito-temporal regions. The conclusion was that patterns of prefrontal brain activity related to episodic memory differed between persons with high versus low risk for AD, and lowered prefrontal activity may predict subsequent disease. In a final study SPECT was used to map patterns of rCBF in an activated state (an episodic encoding task) and in a rest condition in persons with mild AD and in healthy elderly control persons. A reduction of rCBF in temporoparietal regions that was more pronounced in mild AD in the activated encoding task was observed. The conclusion was that there are rCBF differences between mild AD patients and healthy controls in temporoparietal regions, and the temporoparietal reduction is more pronounced during activation than during rest which might be important in the early diagnosis of AD. Taken together, these findings show that level of neuropsychological function, notably episodic memory, can be systematically related to functional disturbances in the LHPA axis and to the function of temporoparietal and prefrontal brain regions in AD patients. These changes are detectable in patients with risk for AD and in an early phase of AD which suggests that the obtained results might be important for early diagnosis of AD.
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Amyloid β-protein, Cystatin C and Cathepsin B as Biomarkers of Alzheimer's DiseaseSundelöf, Johan January 2010 (has links)
It is suggested that Alzheimer’s disease (AD) is caused by an imbalance between production, degradation and clearance of the amyloid-β (Aβ) protein. This imbalance leads to aggregation of Aβ and tau proteins and neurodegeneration in the brain. Today there is increasing evidence that the balance between the protease cathepsin B and the protease inhibitor cystatin C affects the tendency for Aβ to aggregate. The primary aim of this thesis was to investigate Aβ, cystatin C and cathepsin B levels in blood and cerebro-spinal fluid (CSF) in relation to the risk of AD. Studies I & II were based on the re-examinations of participants, at ages 70 and 77, in the Uppsala Longitudinal Study of Adult Men (ULSAM), a community-based prospective study initiated in 1970 (participants then being 50 years of age). In ULSAM, low plasma Aβ1-40 (Study I) and low serum cystatin C levels (Study II) were associated with a higher risk of AD. Studies III & IV were based on a cross-sectional sample of people with AD, mild cognitive impairment and healthy controls, recruited at three Swedish Memory Disorder units: Uppsala University Hospital, Uppsala, Skåne University Hospital, Malmö, and Karolinska University Hospital, Huddinge, Stockholm. In Study III, CSF cystatin C levels were positively correlated with both Aβ1-42 and tau levels. In Study IV, individuals with AD had higher mean plasma cathepsin B levels than healthy controls. In conclusion, low plasma Aβ1-40 and low serum cystatin C levels may precede clinically manifest AD in elderly men, cystatin C levels are positively correlated with Aβ1-42 and tau levels in CSF, and mean plasma cathepsin B levels are higher in people with AD compared to healthy controls. In addition to Aβ1-42 and tau levels in CSF, Aβ1-40, cystatin C and cathepsin B levels in blood may reflect the risk of AD.
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Molecular Mechanisms of Tau Protein Aggregation InhibitionAkoury, Elias 30 September 2013 (has links)
No description available.
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Plaque deposition and microglia response under the influence of hypoxia in a murine model of Alzheimer\'s diseaseViehweger, Adrian 03 January 2014 (has links) (PDF)
Clinical findings have linked multiple risk factors and associated pathologies to Alzheimer\'s disease (AD). Amongst them are vascular risk factors such as hypertension and pathologies such as stroke. Coexistence of AD and these associated pathologies worsenes dementia, the clinical hallmark of the disease, as compared to pure AD. One general common denominator of these associated pathologies is the presence of hypoxic tissue conditions. It was asked the question, whether there exists a mutual, causal interaction between hypoxia and AD pathology, that could explain the clinical observations. Alternatively, the worsened clinical state of multiple brain pathologies could \"simply\" be the consequence of multimorbidity, i.e. accumulated disease load, without any causal interaction between the constituents. To approach this question whether hypoxia influences AD progression, use was made of a murine animal model of AD (transgenic mice: APPswe, PSEN1dE). Animals of two ages (8 and 14 months, \"young\" and \"old\" respectively) and two genotypes (transgenic and wild- type) were either treated under hypoxia or normoxia, corresponding to 8% and 21% oxygen, for 20 consecutive days. The resulting changes in the brain were assessed with a variety of techniques, namely by histology, ELISA, dot and Western blotting. Additional experiments in primary cell cultures were performed.
Animals exposed to hypoxia showed an increased hematocrit (HCT), weight loss, reactive angiogenesis, but no infarctions. This illustrates that our hypoxic treatment put significant stress on the animals, without causing major pathologies. A large number of variables exists that could potentially be measured to assess the effect of hypoxia on AD. The focus was put on three of them: First, there is the Abeta1-42- protein, known to be the Abeta- isoform associated with the most detrimental disease progression. In AD, the self-combinatory Amyloid- beta peptide (Abeta) accumulates in the brain in so- called plaques, which is a main histologic finding of the disease. Its quantity was determined through histology and ELISA.
Secondly, it was attempted to estimate the structural quality of the Abeta- protein by assessing the amount of A!- oligomers present. Abeta- protein does self- accumulate in various grades of complexity, i.e. as monomer, oligomer or fibril. Since oligomers are known to be the most neurotoxic \"species\" of the Abeta- protein, it was hypothesized that under hypoxic treatment their quantity could increase.
And third, the organism\'s response to the Abeta- protein stimulus was investigated. Microglial cells have been described as the first cells to encounter the Abeta- protein \"threat\" in the shape of plaques, i.e. Abeta- protein aggregates. They then try to encapsulate and subsequently degrade them. Therefore, the attention was put on this cellular population.
It was asked whether hypoxia could change the Abeta- protein quantity in the brain. This was assessed in two ways: First histologically, by staining for Abeta- protein depositions and quantifying them. Second, an ELISA was performed. Our findings state that hypoxic treatment does not alter the Abeta1-42 protein load in the brain, neither in young nor old animals, as assessed by histology and by total ELISA quantification of Abeta1-42 protein.
Since hypoxia did not alter the quantity of the Abeta- protein, it was asked whether it influenced it qualitatively? If hypoxia increased oligomer formation, this change in the spectrum of the Abeta- species could, without any change in total Abeta- protein load, lead to increased neurotoxicity in animals under hypoxia. Initial experiments showed that oligomer formation in the brain seems to increase. However, this was not statistically significant and future experiments are necessary to evaluate this hypothesis further.
It was then asked, whether hypoxia alters the cellular response to the protein. The total number of microglia in the hippocampal dentate gyrus, our structure of interest for practical purposes, and, it can be argued, by extension the brain, changes dynamically with various factors. First, transgenic animals present an increase in microglia. Second, microglia increase with age. Third, microglia decrease under hypoxia, but only do so significantly in old animals. Next, a parameter called \"plaque occupancy\" was coined to assess the microglia function to confront Abeta- plaques. Plaque occupancy is defined as the number of microglia in spatial proximity to one square millimeter of Abeta- plaque. This means, that microglia restricting one plaque are counted, and then normalized to this plaque\'s area. It was hypothesized that hypoxia would decrease plaque occupancy. Indeed, plaque occupancy roughly halved under hypoxia.
Summarizing, our results demonstrate that long- term exposure to hypoxia significantly reduces the number of microglia. The reduced number results in significantly reduced plaque occupancy and compromizes the function of microglia to confront Abeta- plaques. The Abeta1-42 load, however, is not affected. On the other hand, Abeta shows an increased trend towards oligomer formation. A variety of possible explanations to these phenomena have been presented, that in our opinion deserve further investigation.
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O cuidador familiar de pessoa com doen?a de Alzheimer: hist?ria oral de vidaAguiar, Virginia Simonato 26 June 2013 (has links)
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Previous issue date: 2013-06-26 / The aim of the present study was to understand the feelings and the difficulties faced
by the family caregiver in the care of the person affected by Alzheimer`s Disease
(AD). It is a descriptive, exploratory study with a qualitative approach, using the oral
life history proposed by Bom Meihy as the method. Data collection was conducted in
the Basic Health Unit of Candelaria, located in Natal -RN, with five collaborators that
carry out the role of family caregivers for people affected by Alzheimer`s disease (AD)
and are members of the Group "Caring for those who Care". Caregi vers who resided
with the affected family member for at least one year were selected for the study, and
as a collection tool, it was opted to use semi-structured interviews via a script of open
questions, recorded by permission of the collaborators, then t ranscribed and
subsequently returned to respondents for checking the contents described. To
analyze the results, the collaborators narrative technique was used in conjuction
with the specific literature on the subject.The discussions were organized around five
themes inherent to the guiding questions, and defined as follows: the incorporation of
the role of the family caregiver; life before and after assuming the role of caregiver,
the caregiver`s feelings and attitudes after assuming the care, difficulti es in caring,
participation of the group as a foundation for caregivers. The stories showed many
difficulties in the daily routine of the caregivers, and also that their participation in the
group "Caring for those who Care" helps them in maintaining the q uality of their lives.
The results open possibilities for the construction of new forms of approach and care
for the people who fulfill the role of family caregiver contributing to strengthening of
subsidies that help them better face the daily difficulti es.This study helped shed light
on the fact that being a family caregiver of a person affected by AD is a suffered,
exhausting and stressful condition involving much self-denial in one?s life. The
situation experienced by these collaborators is considered a public health issue, and
thus highlights the urgency for governmental political -social actions, besides the
programs of care and health promotion for this target group. / O presente estudo teve por objetivo compreender os sentimentos e as dificuldades enfrentadas pelo cuidador familiar no cuidado ? pessoa acometida pela Doen?a de Alzheimer. Trata-se de estudo descritivo, explorat?rio, com abordagem qualitativa, utilizando como m?todo a hist?ria oral de vida, proposto por Bom Meihy. A coleta dos dados foi realizada na Unidade B?sica de Sa?de de Candel?ria, situada em Natal-RN, com cinco colaboradores que desempenham papel de cuidadores familiares de pessoas acometidas pela Doen?a de Alzheimer (DA) e s?o integrantes do Grupo Cuidando de quem Cuida . Foram selecionados para o estudo, cuidadores que residiam com familiar acometido h? pelo menos um ano e, como instrumento de coleta, optou-se por entrevistas semiestruturadas atrav?s de roteiro de quest?es abertas em que as mesmas foram gravadas com permiss?o dos colaboradores, transcritas na ?ntegra e posteriormente devolvidas aos entrevistados para confer?ncia dos conte?dos descritos. Para a an?lise dos resultados, utilizou-se a t?cnica da narrativa dos colaboradores em interlocu??o com a literatura espec?fica sobre a tem?tica. As falas foram organizadas em torno de cinco temas inerentes ?s quest?es norteadoras e, assim definidos: a incorpora??o do papel de cuidador familiar; a vida antes e ap?s assumir o papel de cuidador; sentimentos e posicionamentos do cuidador ap?s assumir o cuidado; dificuldades no cuidado; participa??o do grupo como alicerce para os cuidadores. As hist?rias mostraram muitas dificuldades na rotina di?ria de vida desses cuidadores e a manuten??o da qualidade de suas vidas, atrav?s das participa??es no Grupo Cuidando de quem Cuida . Os resultados possibilitam a constru??o de novas formas de abordagem e cuidado ?s pessoas que desempenham o papel de cuidador familiar, ao contribuir para o fortalecimento de subs?dios que auxiliem no enfrentamento real das dificuldades di?rias. Tal estudo permitiu compreender que ser cuidador familiar de uma pessoa acometida pela DA ? uma condi??o sofrida, desgastante e estressante envolvendo muitas ren?ncias em suas vidas. Considera-se a situa??o vivenciada pelos colaboradores uma quest?o de sa?de p?blica e, assim, evidencia-se a prem?ncia de medidas governamentais de car?ter pol?tico-social, al?m de programas de aten??o e promo??o da sa?de ao referido p?blico alvo
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Efeitos do hormônio tireoideano T3 no sistema nervoso central associados a diabetes melito induzida por aloxana. / Effects of thyroid hormone T3 in the central nervous system associated with diabetes mellitus induced by alloxan.Fernanda Prieto de Almeida 23 March 2016 (has links)
Doenças neurodegenerativas vem sendo relacionadas a alterações no metabolismo de glicose e deficiência e/ou resistência à insulina encefálica. Além desta relação, parece existir uma modulação dos hormônios tireoideanos (HT) sobre a sinalização de insulina e a função do sistema nervoso central (SNC). O objetivo desse trabalho foi analisar a relação entre o hipertireoidismo e o SNC, associados a DM. Para isso, ratos Wistar adultos foram injetados com monoidratado de aloxana ou veículo e tratados com T3 durante 30 dias, sendo avaliados em testes comportamentais e posteriormente analises proteicas de regiões do córtex e hipocampo. O tratamento crônico com T3 produziu um efeito ansiolítico e um atraso na aquisição de informações aprendidas, apesar da consolidação não ser modificada. Por outro lado, o T3 promoveu a melhora do processo neurodegenerativo e na via da sinalização da insulina no hipocampo de animais diabéticos. Esses dados sugerem, de modo geral, um efeito benéfico do HT sobre o a função encefálica de animais diabéticos. / Neurodegenerative diseases has been related to changes in glucose metabolism and deficiency and /or resistance to brain insulin. In this respect, there appears to be a modulation of thyroid hormones (TH) on insulin signaling and function of the central nervous system (CNS). The objective of this study was to analyze the relationship between hyperthyroidism and the CNS associated with DM. For this, Wistar adult rats were injected with alloxan monohydrate or treated with vehicle and T3 for 30 days and evaluated in behavioral tests and subsequent analyzes of protein in the cortex and hippocampus regions. Chronic treatment with T3 produced an anxiolytic effect and a delay in the acquisition of information, although consolidation not be modified. Furthermore, T3 allowed improvement of the neurodegenerative process and pathway of insulin signaling in the hippocampus of diabetic rats. These data suggest, in general, a beneficial effect of TH on the brain function of the diabetic animals.
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Convivência familiar com o idoso acometido pela doença de alzheimer: estudo de caso / Family living with elderly sufferers of Alzheimer s Disease: a case studyGarcia, Francielli Gonçalves 18 December 2006 (has links)
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Previous issue date: 2006-12-18 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Trata-se de um estudo de caso de dois casos , que visa compreender a convivência familiar com o idoso acometido pela Doença de Alzheimer (DA), por meio da investigação de suas características, de como o diagnóstico foi percebido e assimilado pela família, da observação das informações sobre a doença, dos suportes recebidos e da maneira que lidam com esta convivência. Foram entrevistados 11 familiares de dois idosos: 05 do caso 01 (José), acometido pela DA há seis anos e usuário de serviços públicos de saúde; 06 do caso 02 (Maria), há doze anos com DA e usuária de serviços particulares de saúde. Foi utilizado um roteiro de entrevista contendo perguntas norteadoras sobre o paciente, a família, os cuidados prestados e a convivência com o doente. Os depoimentos foram analisados através do método Análise de Conteúdo e da técnica Análise Temática. Os temas encontrados foram: relações familiares, assistência à saúde, cuidados prestados, mudanças, enfrentamento e necessidade de suporte. Constatou-se que os familiares estão sujeitos a sobrecargas de ordem física, psíquica e emocional; os cuidados prestados são exercidos, principalmente, por mulheres e estão relacionados às necessidades fisiológicas; as principais mudanças ocorridas na família foram observadas na rotina, nos papéis e na perda dos sonhos, por parte dos familiares; o diagnóstico foi assimilado considerando o grau de instrução do familiar e as informações prévias sobre a doença; estas foram fornecidas pelos profissionais de saúde dos serviços que utilizam; os suportes recebidos correspondem à ajuda mútua entre os membros da família e o auxílio nos cuidados é feito por cuidadoras informais contratadas, que não são profissionais de saúde, não pertencem à família, mas possuem vínculo afetivo; o enfrentamento de situações difíceis da convivência se dá por meio da crença e fé em Deus; as necessidades de suporte são: fornecimento de informação sobre a doença para a família e para a população; criação de espaços para discussão sobre o assunto; e, identificação precoce da doença por parte de pessoas leigas, para que possam buscar ajuda profissional. Concluiu-se que os familiares devem ser tratados como clientes pelos serviços de saúde, pois também estão submetidos ao adoecimento decorrente do estresse gerado pela convivência familiar com o idoso acometido pela Doença de Alzheimer. / It consists of a case study of two cases that aims to comprehend the way that families live and cope with elderly sufferers of Alzheimer s disease (AD) through the investigation of the family characteristics, the way the diagnostic was perceived and understood by them, their level of information about the disease, received support and the way they cope with the situation. Eleven family members of 2 elderly were interviewed: 05 from case 1 (José) who suffers from AD for 6 years and uses the public health service; 06 from case 2 (Maria) who suffers from AD for 12 years and uses the private health service. The interview schedule comprised of orientating questions about the patient, the family, the care given and the daily life with the ill. The interviewees speeches were analysed through the Content Analysis Method and the Thematic Analysis technique. The themes found were: family relations, health assistance, care given, changes, coping and support need. It was observed that family members are submitted to physical, psychological and emotional strains; the care of the sick is mainly given by women and is related to the sick physiological needs; the main observed changes in the family life occurred in their routine, in their roles and sleep patterns. Given the levels of schooling and knowledge about the disease, family members were capable of understanding the diagnostics and such information about the disease was given by health professionals. The received support consists of: mutual help in between family members and the aid of informal contracted carers who are not health professionals and do not belong to the family but have an emotional bond. Coping with the difficult situation of living with the ill is overcome by faith in God. The main support needs are: information supply to the family members and general public; creation of discussion channels for the subject; early identification of disease by laypeople so they can reach professional help. It was concluded that family members must be treated by the health services as clients since they also become ill due to the strains of living and coping with the elderly sufferers of Alzheimer s disease.
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Desenvolvimento de ferramentas biotecnológicas a partir de recursos naturais para o tratamento da doença de AlzheimerSantos, Rosiane dos 14 February 2013 (has links)
Alzheimer´s disease (AD) is a neurodegenerative disorder responsible for the largest number of cases of dementia in the elderly. The brain regions associated with the frontal cortex and
the hippocampus are the most affected by the changes arising from the AD, resulting in loss of neuronal function, and the loss of memory and cognitive ability. In the cellular level, AD is
associated with reduced levels of acetylcholine (ACh) in the synaptic process, decreasing cortical cholinergic neurotransmission. ACh is a neurotransmitter found in the brain and at(in the) neuromuscular junctions, forming part of the parasympathetic nervous system, your activity and staying in the synaptic cleft is regulated by hydrolysis catalyzed by
acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) enzymes that modulate the levels of Ach in the nervous system. The outlook for new targets cholinesterase inhibitors has
stimulated research using bioactive compounds of natural products and also the use of an animal model that provides better understanding of the mechanisms of cognitive
development. Because they are microorganisms that produce secondary given this, metabolites of great importance for bioprospecting, a study of the anticholinesterase activity
of compounds isolated from the endophytic fungus Phomopsis sp. (PE) associated with mangabeira (Hancornia speciosa). Furthermore, it was investigated the effect of menthol on
the adult zebrafish memory in the passive avoidance test. The menthol was selected taking to account the screening conducted by our research group in previous work, where this
compound showed potent anticholinesterase activity. In the search for promising compounds to anticholinesterase drugs, the present study aimed to evaluate the in vitro activity of the
crude extract of the fungus, as well as their isolated compounds 5-methyl mellein (1), nectriapyrone (2), tyrosol (3) and tryptophol (4) in AChE and BuChE in vivo evaluation the
effect of menthol on the acquisition of learning and memory consolidation. In all assays were obtained encouraging results. The crude extract of PE and its isolated compounds were
effective to inhibit cholinesterase, and the tryptophol (4) was the most promising because it showed dual action on the enzymes being selective to BuChE. The study of exposure to
menthol zebrafish showed that this compound produces no effect on memory. On the other hand, at all doses tested menthol reverses amnesia induced by scopolamine. This study,
therefore, demonstrated the potencial use of these compounds isolated from PE as source of novel agents for the treatment of AD and that menthol may be indicated as therapeutic alternative for the treatment of memory deficits. / A doença de Alzheimer (DA) é uma desordem neurodegenerativa responsável pelo maior número de casos de demência em idosos. As regiões cerebrais associadas ao córtex frontal e ao hipocampo são as mais comprometidas pelas alterações decorrentes da DA, resultando em perda da função neuronal, além de perda progressiva da memória e declínio cognitivo. Em nível celular, a DA está associada à redução das taxas de acetilcolina (ACh) no processo sináptico, diminuindo aneurotransmissão colinérgica cortical. A ACh é um neurotransmissor encontrado no cérebro e nas junções neuromusculares, compondo parte do sistema nervoso parassimpático, sua atividade e permanência na fenda sináptica são reguladas por hidrólise catalisadapela acetilcolinesterase (AChE) e pela butirilcolinesterase (BuChE) enzimas que modulam os níveis de ACh no sistema nervoso. A perspectiva por novos alvos inibidores das colinesterases tem estimulado pesquisas utilizando compostos bioativos de origem natural e também a utilização de modelo animal que proporcione melhor compreensão dos mecanismos do desenvolvimento cognitivo. Diante disso, pelo fato deserem microrganismos produtores de metabólitos secundários de grande importância para bioprospecção, foi realizado um estudo da atividade anticolinesterásica de compostos isolados do fungo endofítico Phomopsis sp. (PE) associado à mangabeira (Hancornia speciosa Gomes). Além disso, foi investigado o efeito do mentol sobre a memória de zebrafishadulto através do teste da esquiva passiva. O mentol foi selecionado tomando-se como base o screening realizado por nosso grupo de pesquisa, onde esse composto apresentou potente atividade anticolinesterásica. Na busca por compostos promissores a fármacos anticolinesterásicos, opresente trabalho teve como objetivo a avaliação in vitroda atividade do extrato bruto do fungo, e de seus compostos isolados 5-metil meleína (1), nectriapirona (2), tirosol (3) e triptofol (4) frente às enzimas AChE e BuChE, assim como a avaliação in vivodo efeito do mentol sobre a aprendizagem e consolidação da memória. O extrato bruto do PE e os seus compostos isolados apresentaram efeito na inibição das colinesterases, sendo o triptofol (4) o mais promissor, pois apresentou ação dual sobre as enzimas sendo seletivo para BuChE. O estudo da exposição de zebrafishao mentol revelou que este composto não produz efeito sobre a memória. Por outro lado, em todas as concentrações testadas o mentol foi capaz de reverter a amnésia induzida por escopolamina. Diante dos resultados, conclui-se que os compostos isolados do PE podem ser considerados como alternativas para o desenvolvimento de novos fármacos anticolinesterásicos e que o mentol pode ser indicado como alternativa terapêutica para tratamento de déficits de memória.
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Análise de wavelets com máquina de vetor de suporte no eletrencefalograma da doença de Alzheimer / Wavelets analysis with support vector machine in Alzheimer\'s disease EEGPaulo Afonso Medeiros Kanda 07 March 2013 (has links)
INTRODUÇÃO. O objetivo deste estudo foi responder se a transformada wavelet Morlet e as técnicas de aprendizagem de Máquina (ML), chamada Máquinas de Vetores de Suporte (SVM) são adequadas para procurar padrões no EEG que diferenciem controles normais de pacientes com DA. Não há um teste de diagnóstico específico para a doença de Alzheimer (DA). O diagnóstico da DA baseia-se na história clínica, neuropsicológica, exames laboratoriais, neuroimagem e eletroencefalografia. Portanto, novas abordagens são necessárias para permitir um diagnóstico mais precoce e preciso e para medir a resposta ao tratamento. EEG quantitativo (EEGq) pode ser utilizado como uma ferramenta de diagnóstico em casos selecionados. MÉTODOS: Os pacientes eram provenientes do Ambulatório do Grupo de Neurologia Cognitiva e do Comportamento (GNCC) da Divisão de Clínica Neurológica do HCFMUSP ou foram avaliados pelo grupo do Laboratório de Eletrencefalografia Cognitiva do CEREDIC HC-FMUSP. Estudamos EEGs de 74 indivíduos normais (33 mulheres/41 homens, com idade média de 67 anos) e 84 pacientes com provável DA leve a moderada (52 mulheres/32 homens, idade média de 74,7 anos. A transformada wavelet e a seleção de atributos foram processadas pelo software Letswave. A análise SVM dos atributos (bandas delta, teta, alfa e beta) foi calculada usando-se a ferramenta WEKA (Waikato Ambiente para Análise do Conhecimento). RESULTADOS: Na classificação dos grupos controles e DA obteve-se Acurácia de 90,74% e área ROC de 0,90. Na identificação de um único probando dentre todos os demais se conseguiu acurácia de 81,01% e área ROC de 0,80. Desenvolveu-se um método de processamento de EEG quantitativo (EEGq) para uso na diferenciação automática de pacientes com DA versus indivíduos normais. O processo destina-se a contribuir como complemento ao diagnóstico de demência provável principalmente em serviços de saúde onde os recursos sejam limitados / INTRODUCTION. The aim of this study was to answer if Morlet wavelet transform and machine learning techniques (ML), called Support Vector Machines (SVM) are suitable to look for patterns in EEG to differentiate normal controls from patients with AD. There is not a specific diagnostic test for Alzheimer\'s disease (AD). The diagnosis of AD is based on clinical history, neuropsychological testing, laboratory, neuroimaging and electroencephalography. Therefore, new approaches are needed to allow an early diagnosis and accurate to measure response to treatment. Quantitative EEG (qEEG) can be used as a diagnostic tool in selected cases. METHODS: The patients came from the Clinic Group Cognitive Neurology and Behavior (GNCC), Division of Clinical Neurology HCFMUSP or evaluated by the group of the Laboratory of Cognitive electroencephalography CEREDIC HCFMUSP. We studied EEGs of 74 normal subjects (33 females/41 men, mean age 67 years) and 84 patients with mild to moderate probable AD (52 females/32 men, mean age 74.7 years. Wavelet transform and the selection of attributes were processed by software Letswave. SVM analysis of attributes (bands delta, theta, alpha and beta) was calculated using the tool WEKA (Waikato Environment for Knowledge analysis). RESULTS: The group classification of controls and DA obtained an accuracy of 90.74% and ROC area 0.90. The identification of a unique proband among all others was achieved with accuracy of 81.01% and ROC area 0.80. It was developed a method of processing EEG quantitative (qEEG) for use in automatic differentiation of AD patients versus normal subjects. This process is intended to complement the diagnosis of probable dementia primarily in health services where resources are limited
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Orientação topográfica na doença de Alzheimer / Topographic disorientation in Alzheimer´s diseaseCarla Cristina Guariglia 20 April 2006 (has links)
Introdução: a desorientação topográfica é um sintoma comum em pacientes com doença de Alzheimer (DA), no entanto não tem tão estudada quanto outros sintomas da DA. Objetivos: Verificar a ocorrência da desorientação topográfica em pacientes com DA e identificar quais transtornos neuropsicológicos estão relacionados com a desorientação. Métodos: Foram avaliados vinte e sete pacientes com DA provável (12 do sexo feminino, 14 com DA com demência de leve intensidade) e 30 indivíduos controles sem demência (21 do sexo feminino). Os pacientes foram submetidos a um questionário específico sobre orientação topográfica e foram submetidos aos seguintes testes: Mini Exame do Estado Mental, extensão de dígitos, fluência verbal, teste de cancelamento, teste dos blocos de Corsi, localização de pontos no espaço, julgamento de orientação de linhas, cópia de figuras em três dimensões e figuras sem sentido e testes de rotação mental. Foram realizados testes de reconhecimento de marcos topográficos, orientação pessoal, descrição de rotas, localização de cidade no mapa do Brasil. Resultados: Pacientes e controles não apresentaram diferença quanto à escolaridade e gênero. Houve diferença entre pacientes e controles no questionário sobre orientação topográfica e em todos os testes utilizados, exceto nas tarefas de funções vísuo-espaciais. O grupo de pacientes com demência de leve intensidade demonstrou diferença no questionário sobre orientação topográfica, descrição de rotas, reconhecimento de marcos topográficos, orientação espacial julgamento de orientação de linhas e localização de cidades no mapa. Apenas o reconhecimento de marcos topográficos, foi capaz de diferenciar entre pacientes com demência de leve ou de moderada intensidade. Conclusões: O questionário sobre orientação topográfica demonstrou que até mesmo os pacientes com DA com demência de leve intensidade tiveram desorientação topográfica. Os testes de reconhecimento de marcos topográficos, xi orientação pessoal egocêntrica e alocêntrica, estão alterados precocemente e podem contribuir para a desorientação topográfica, A memória operacional espacial e as funções visuo-espaciais não estão comprometidas inicialmente e provavelmente não contribuíram para a desorientação topográfica em pacientes com demência de leve intensidade. No entanto, pacientes com demência de intensidade moderada demonstraram comprometimento nas tarefas de memória operacional especial e testes de funções vísuoespaciais, o que provavelmente contribuiu para a desorientação topográfica nestes pacientes / Background: Topographical disorientation is a common symptom in patients with Alzheimer´s disease (AD) that has not been as extensively studied as other common manifestations of this disease. Objective: To verify the occurrence of topographical disorientation in patients with Alzheimer\'s disease (AD) and to identify which neuropsychological dysfunctions are causally related to the presence of this manifestation. Methods: Twenty seven patients meeting criteria for probable AD (12 female, 14 with mild dementia) and 30 subjects (21 female) without dementia were analyzed. The subjects and the caregivers were interviewed with a questionnaire on topographical orientation. The following tests were given: Mini mental state examination (MMSE), digit span, verbal fluency, cancellation task, Corsi\'s block tapping test, point localization, line orientation judgment, three dimension and nonsense figure copy and mental rotation tests. Landmarks recognition, personal orientation, recalling routes were tested in a descriptive task and geographic knowledge was evaluated with a Brazilian map. Results: Patients and control subjects were not different regarding schooling years and gender. There were differences between patients and controls in the questionnaire on topographical orientation and in all tests except in visual spatial tasks. Patients with mild dementia had difference in the questionnaire, recalling routes, landmark recognition, personal orientation, geographical knowledge and line orientation judgment. Only the landmark recognition test was found to differentiate between patients with mild or moderate dementia. Conclusions: The topographic orientation questionnaire showed that even in mild dementia, AD patients have topographical disorientation. The landmark recognition, self-centered and world-centered orientation were precociously affected and may contribute for topographical disorientation. Spatial working memory and spatial visual functions are not compromised initially and xiii probably did not contribute for topographical disorientation in the patients with mild dementia. However, patients with moderate dementia showed impairment in spatial working memory and spatial visual tests, which may have contributed to the topographic disorientation of these patients
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