Aumento das concentrações de cortisol em idosos com Doença de Alzheimer (DA) tem sido relatado como resultado da ausência de inibição do eixo hipotálamo-pituitária-adrenal (HPA) em decorrência da disfunção hipocampal observada nestes indivíduos. Além disso, associação entre concentrações elevadas de cortisol e comprometimento da memória tem sido evidenciada em idosos saudáveis. Entretanto, pouco se sabe a respeito do envolvimento do estresse nas concentrações de cortisol, no desempenho cognitivo e nas estratégias de coping tanto em idosos saudáveis como naqueles com comprometimento cognitivo leve (CCL) e DA. Assim, este estudo teve o objetivo de investigar a associação entre intensidade de estresse, concentrações de cortisol, estratégias de coping e desempenho cognitivo em idosos saudáveis, com CCL e DA. Para isto, concentrações basais de cortisol salivar foram analisadas em uma amostra composta por 40 idosos saudáveis, 31 idosos com CCL amnéstico e 40 indivíduos com DA leve. O desempenho cognitivo global foi avaliado a partir do mini-exame do estado mental (MEEM), o desempenho da memória através da Bateria Breve de Avaliação Cognitiva (BBAC) e pelo teste de extensão de dígitos na ordem inversa. A intensidade do estresse foi avaliada a partir da Lista de Sintomas de Stress (LSS) e as estratégias de coping através da Escala de Coping de Jalowiec (ECJ). Desta forma, foram observadas concentrações de cortisol marginalmente mais elevadas nos idosos com DA do que nos idosos saudáveis (p = 0.062). Além disso, verificou-se associação positiva entre cortisol e desempenho da memória nos idosos saudáveis (p = 0.008), enquanto correlação negativa entre estas variáveis foi observada no grupo CCL (p = 0.011). Não foi verificada associação significativa nos idosos com DA (p > 0.05). Ademais, observou-se correlação positiva entre as concentrações de cortisol e a intensidade de estresse somente nos idosos com CCL (p = 0.056). Com relação às estratégias de enfrentamento, observou-se que os idosos com CCL que elegem o coping focado no problema apresentam intensidade de estresse menor que os idosos que utilizam o coping focado na emoção (p = 0.048). Estes resultados sugerem que a associação entre concentrações de cortisol, desempenho da memória, intensidade de estresse e coping varia em função da presença ou ausência de comprometimento cognitivo e da percepção das limitações cognitivas / Increased cortisol levels have been reported in elderly with Alzheimers disease (AD) as a result of the lack in the hypothalamic-pituitary-adrenal (HPA) axis inhibition as a function of hipocampal atrophy observed in those subjects. Moreover, association between high cortisol levels and memory impairment has been demonstrated in healthy elderly subjects. However, little is known about the stress involvement in the cortisol levels, in the cognitive performance and in the coping strategies in both elderly with mild cognitive impairment (MCI) and with AD. Thus, this study aimed to investigate the association between stress intensity, cortisol levels, coping strategies and cognitive performance in healthy elderly, subjects with CCL and with DA. Basal salivary cortisol was measured in a sample composed of 40 healthy elderly subjects, 31 individuals with amnestic MCI and 40 subjects with mild AD. Global cognitive performance was evaluated with the Mini Mental State Exam (MMSE) and memory performance was assessed with the Brief Cognitive Screening Battery (BCSB) and the backward digit span test. Stress intensity was evaluated with the Stress Symptoms List (SSL) and coping strategies with the Jalowiec Coping Scale (JCS). Marginally higher cortisol levels were observed in the subjects with AD group in comparison with healthy elderly (p = 0.062). Furthermore, positive association between cortisol levels and memory performance was observed in the healthy elderly (p = 0.008) while negative correlation was observed between these variables in the MCI group (p = 0.011). No significant association was exhibited in the AD group (p > 0.05). Moreover, positive correlation between cortisol levels and stress intensity was observed only in the MCI group (p = 0.056). Regarding the coping strategies, it was observed that those MCI subjects who elect problem focused coping exhibit higher stress intensity than those MCI who use emotion focused coping (p = 0.048). These results suggest the association between cortisol levels, memory performance, stress intensity and coping strategies may vary as a function of the presence or absence of cognitive impairment and as a function of the cognitive deficits awareness

Doentes que apresentam comprometimento cognitivo, como a doença de Alzheimer (DA), podem apresentar maior prevalência de infecções bucais. Entre elas, a periodontite crônica é uma infecção frequente associada ao aumento do nível sérico de marcadores inflamatórios, e recentemente tem sido apontada como um fator que pode relacionar-se à progressão da DA através de seus mecanismos sistêmicos. O objetivo deste trabalho foi verificar a prevalência de infecções bucais e os níveis séricos de IL-1beta, TNF- alfa e IL-6 em doentes com DA, comprometimento cognitivo leve (CCL) e idosos não-demenciados. Foram avaliados 65 idosos (25 com DA, 19 com CCL e 21 saudáveis). A avaliação incluiu o Mini Exame do Estado Mental, Questionário de Atividades Funcionais (Pfeffer), Avaliação Periodontal, índice CPOD, Questionário de Avaliação Clínica Orofacial (EDOF-HC) e avaliação de concentração sérica de IL-1beta, TNF-alfa e IL-6. Os doentes com DA e CCL apresentaram maior quantidade de dentes ausentes e por um período maior de tempo do que os idosos saudáveis (P= 0.038) e a doença periodontal (DP) foi a causa principal das perdas dentárias (P= 0.035). Os doentes apresentaram maior prevalência de candidose do que os controles (P= 0.05). As análises de correlação demonstraram que quanto maior a concentração de IL-6, pior a funcionalidade pelo índice de Pfeffer (P < 0,001; Pearson) e pior o índice cognitivo (P=0,018; Pearson). Por outro lado, quanto maior a concentração de TNF-alfa, piores os índices IS, PCS média e máxima e PCI média e máxima (P < 0,001; Pearson), maior o tempo de uso de próteses (P=0,010; Pearson) e pior o índice de placa O´Leary (P=0,008; Pearson). IL-6 e TNF-alfa se correlacionaram positivamente (P < 0,001; Pearson). Conclui-se que há um aumento sérico de citocinas associado ao comprometimento cognitivo e à doença periodontal. Estudos futuros poderão esclarecer os mecanismos que determinam aumento de IL-6 nas demências e aumento de TNF-alfa nas infecções periodontais e elucidar possíveis associações entre eles / Patients that present cognitive impairment, as Alzheimer´s Disease (AD), may have high prevalence of oral infections. Among them, chronic periodontitis is often associated to the increase of seric inflammatory biomarkers, and it recently has been referred as a factor than can change the progression of AD by its systemic mechanisms. The objective of this study was to investigate the prevalence of oral infections and seric levels of IL-1alfa, TNF-alfa and IL-6 in patients with AD, mild cognitive impairment (MCI) and non demented elderly. Sixty-five elderly were evaluated (21 with AD, 8 with MCI and 15 healthy). The evaluation included the Mini Mental State Exam, Questionnaire of Functional Activities (Pfeffer), periodontal evaluation, DMFT, Clinical Orofacial Questionnaire (EDOF-HC) and seric concentrations of IL-1beta, TNF-alfa and IL-6. The patients with AD and MCI had more absent teeth and for a longer period of time than the healthy elderly (P= 0.038) and periodontal disease (PD) was the main cause of teeth losses (P= 0.035). The patients had higher prevalence of candidiasis than the controls (P= 0.05). The serum level of IL-6 was higher in the patients that showed bad performance in the MMSE (P=0.018; Pearson) and daily life activities - Pfeffer (P < 0.001; Pearson). The TNF-alfa serum level was more elevated when patients had PPD, CAL, BI (P < 0.001; Pearson) and O\'Leary plaque index (P=0.008; Pearson). IL-6 e TNF-alfa were positively correlated (P < 0.001; Pearson). In conclusion, there is a seric increase of cytokines associated with the cognitive impairment and periodontal disease. Future studies are necessary to clarify the mechanisms that underlie the increase of IL-6 in dementias and the increase of TNF-alfa in periodontal infections and possible associations between them

Im Zentrum der vorliegenden Arbeit steht die Proteomanalyse des APP23-Mausmodells für die Alzheimer-Krankheit (AK). Es wurden die Gehirnregionen Hippocampus und Cortex der Altersstadien Embryonaltag 16 sowie 1, 2, 7 und 15 Monate untersucht und somit erstmals eine Art „Proteom-Lebensprofil“ eines Mausmodells erstellt. Bei dem Vergleich der APP23-Mäuse mit Wildtypmäusen konnte innnerhalb aller untersuchten Altersstadien und Gehirnregionen eine große Anzahl quantitativer Proteinexpressionsunterschiede festgestellt werden. Interessanterweise bestand jedoch im Hippocampus adoleszenter, zwei Monate alter Mäuse, ein herausragend großer Unterschied. Ein Vergleich der Proteomzusammensetzung zwischen den verschiedenen Altersstadien zeigte, dass spezifisch im Hippocampus der adoleszenten APP23-Mäuse viele entwicklungsbedingte Proteomveränderungen ausgeblieben waren. Zusammen mit der Beobachtung, dass in diesem Altersstadium viele synaptische Proteine in den APP23-Mäusen herunterreguliert waren, weisen die gewonnenen Daten darauf hin, dass ein natürlicher Peak in der hippocampalen Plastizität während der Adoleszenzphase in den APP23-Mäusen ausgeblieben war. Es ist weiterhin bekannt, dass APP als auch eine wichtige Rolle in der embryonalen Neurogenese spielt. Da über diese Prozesse noch wenig bekannt ist, wurde im Rahmen der vorliegenden Studie weiterhin eine grundlegende Untersuchung der murinen embryonalen Gehirnentwicklung durchgeführt. Dabei wurde beobachtet, dass innerhalb eines Zeitraums von zwei Entwicklungstagen die Anzahl an quantitativ veränderten Proteinen konstant ist. Dies könnte die maximal mögliche Veränderungsrate wiederspiegeln, die wiederum einen begrenzenden Faktor für die Geschwindigkeit der Embryonalentwicklung darstellt. Weiterhin stieg im Zuge der Neurogenese die Konzentration zelltypspezifischer Proteine an während im Gegenzug die Konzentration unspezifischer Proteine abnahm. / The work presented here focuses on the analysis of the APP23 mouse model for alzheimer´s disease (AK). Using a proteomics approach; the two brain regions cortex and hippocampus, were analyzed at the ages 1,2,7 and 15 months and at embryonic day 16. Thus, for the first time, a lifetime profile of brain proteome alterations caused by mutant APP expression was created. Protein expression alterations between APP23 and control mice were numerous at all age stages but unexpectedly, the hippocampus of two-month old (adolescent) mice, showed a dramatic peak in the number of altered proteins. When comparing proteome patterns longitudinally between age-stages, protein alterations were largely absent in the hippocampus of adolescent APP23-mice but not in other stages compared. Apparently, the large difference in hippocampal protein pattern changes between two-month old APP23- and wildtype-mice was caused by an absence of distinct developmental changes in APP23-mice. In summary, the absence of longitudinal developmental proteome alterations during adolescence, a developmental stage where neuronal plasticity is prominent and horizontal (disease/control) down-regulation of many proteins related to plasticity suggests the disruption of a normally occurring peak of hippocampal plasticity during adolescence of APP23-mice. APP was also suggested to play an important role in embryonic neurogenesis. Since information about the molecular mechanisms of neurogenesis is scarce, a basic analysis of protein changes during normal embryonic neurogenesis was conducted. Interestingly, the rate of protein concentration change within two days of development was constant. This might represent the maximal rate limiting the speed of embryonic development. During neurogenesis, cell-type specific proteins were up- and unspecific proteins down-regulated. In summary, this study shows that it is of utmost importance to investigate AK even at an early age prior to the occurrence of disease symptoms.

Made available in DSpace on 2016-04-04T18:27:51Z (GMT). No. of bitstreams: 1 Adriana Satomi Horiguchi.pdf: 1179274 bytes, checksum: 050e7a378439e733671628c42e01956e (MD5) Previous issue date: 2010-02-09 / Pontif?cia Universidade Cat?lica de Campinas / This study has the objective of analyzing and comparing the data of emotional stress, burden and life quality which were collected next to informal caregivers of patients with Alzheimer s disease and also comparing these data between Brazilian and Nippon-Brazilian cultures. The sample was composed by 20 caregivers, formed by 10 Brazilian caregivers and 10 Nippon-Brazilians. To collect the data it was used an Identification Form destined for the patient identification (answered by the caregiver), the Identification Form destined for the caregivers, the Stress Symptoms Inventory for Adults, the Life Quality Inventory and the Burden Interview. The general results point out that 75% of informal caregivers present stress, from whom 70% were in the resistance phase. It was detected a high level of failure in the life quality, in the health area, pointing out that this area is deeply affected. In the professional area it was also observed major failing scores. Comparing stress and burden, it was verified a significant difference between caregivers with and without emotional stress for privacy and burden feeling, having higher amounts of burden the participants with stress. Comparing the two groups there was a significant difference between the informal Brazilian caregivers and Nippon-Brazilians referring to the stress percentage. The Brazilian caregivers group obtained higher results of stress intensity in relation to the Nippon-Brazilian caregivers. / Este estudo tem por objetivo analisar e comparar os dados de stress emocional, sobrecarga e qualidade de vida, coletados junto a cuidadores informais de pacientes com a Doen?a de Alzheimer, e tamb?m, de comparar esses dados entre a cultura brasileira e nipo-brasileira A amostra foi composta por 20 cuidadoras, sendo 10 brasileiras e 10 nipo-brasileiras. Para a coleta de dados utilizou-se o Formul?rio de Identifica??o destinado ? identifica??o do paciente (respondido pela cuidadora), o Formul?rio de Identifica??o destinado ?s cuidadoras, o Invent?rio de Sintomas de Stress para Adultos, o Invent?rio de Qualidade de Vida e o Burden Interview. Os resultados gerais revelaram que 75% das cuidadoras informais apresentavam stress, das quais 70% encontravam-se na fase de resist?ncia. Foi constatado um alto n?vel de fracasso em qualidade de vida na ?rea da sa?de, revelando que esta se encontra profundamente afetada. Na ?rea profissional tamb?m foram observados maiores escores de fracasso. Comparando stress e sobrecarga, verificou-se diferen?a significativa entre as cuidadoras com e sem stress emocional para sa?de, privacidade e sentimento de sobrecarga, tendo maiores valores de sobrecarga as participantes com stress. Comparando-se os dois grupos, houve diferen?a significativa entre as cuidadoras informais brasileiras e nipo-brasileiras no que se refere ? porcentagem de stress. O grupo das cuidadoras brasileiras obteve maiores resultados de intensidade do stress em rela??o ao grupo de cuidadoras nipo-brasileiras.

Septinas constituem uma família de proteínas de ligação a GTP que foram inicialmente identificadas em levedura Saccharomyces cerevisiae, mas também estão presentes em outros eucariotos com exceção de plantas. Septinas são purificadas de leveduras, Drosophila e cérebros de mamíferos na forma de filamentos, porém o mecanismo através do qual acorre a formação destes filamentos ainda não é muito bem compreendido. Septinas são constituídas de três regiões principais: um N-terminal variável, um domínio central GTPase altamente conservado e um domínio coiled-coil C-terminal. O gene SEPT4 foi identificado por M. Tanaka e colaboradores a partir do cDNA de cérebro humano e apresentou duas distintas transcrições: Bradeiona ? e ?. Interessantemente, além de cérebro e coração, as proteínas Bradeiona &#913; e &#914;. são detectadas somente em câncer do cólon, reto, próstata e melanoma maligno. Neste trabalho, o gene da proteína Bradeiona &#914; foi subclonado em um vetor de expressão bacteriano, produzido em E. coli e purificado com sucesso. O espectro de dicroísmo circular (CD) mostrou o perfil característico de proteínas com hélices a na estrutura secundária. Resultados de cromatografia de exclusão molecular (SEC) e espalhamento dinâmico de luz (DLS) indicam que a septina Bradeina foi produzida na forma de um estável oligômero com características monodispersivas, que foi subseqüentemente cristalizado em PEG6000. A atividade GTPase da Bradeiona &#914; foi comprovada através da técnica de eletroforese capilar (CE), mostrando-se absolutamente dependente de íons Mg2+. Inibição da atividade GTPase foi verificada em altas concentrações de Mg2+ (maiores que 5 mM). Com a finalidade de caracterizar os domínios preditos da Bradeiona &#914; (Fragmento Conservado e domínio GTPase), essas regiões foram previamente definidas, expressas em E. cozi e purificadas com sucesso. Resultados de CD, SEC, espectroscopia de fluorescência e NMR-600MHz indicam que o FC foi produzido na forma de um estável monômero com pouca estrutura secundária regular. Resultados de DLS e CD indicam que a fusão 6xHis-DGTPase foi produzida na forma de um oligômero com a presença de hélices a na estrutura secundária. A fusão 6xHis-DGTPase mostrou-se instável a altas concentrações na ausência de imidazol. A atividade GTPase da fusão GST+DGTPase foi comprovada, similarmente a Bradeiona , através da técnica de CE. Novamente, verificou-se dependência de íons Mg2+ (para a atividade catalítica) e inibição em altas concentrações de Mg2+. A fusão GST+DGTPase também foi capaz de hidrolisar ATP. Espera-se que as informações relatadas neste estudo proporcionem um alicerce para estudos estruturais/funcionais futuros das proteínas Bradeiona &#913; e &#914;outras septinas. / Septins form a class of eukaryoyic guanine nucleotide-binding proteins that were first identified in budding yeast. Septins purified from yeast, Drosophila and mammalian brain form filaments, however the mechanism by which the filaments assemble is unclear. Septins have a highly conserved structure, which includes a central GTP-binding domain, a variable N-terminal region, and most septins also contain a coiled coil domain at the Cterminus. Bradeion p is one of the splice variants of the human septin gene, SEPT4, recently isolated by expression screening of an adult human brain cDNA library. The Bradeion gene resides at 17q23, and has been shown to present specific expression in both human colorectal cancer, urologic cancers and malignant melanoma. In order to characterize the GTPase activity of Bradeion &#914; , the protein was successfully expressed in E. coli and purified. The recombinant protein was characterized by circular dichroism (CD), dynamic light scattering (DLS) and a novel non-radioactive enzyme assay, which utilizes capillary electrophoresis (EC) to monitor GTP hydrolysis. The CD spectrum exhibited the typical shape characteristic of the presence of helical elements of secondary structure and the DLS pattern was indicative of a monodisperse solution, which was readily crystallized in the presence of PEG6000. GTP hydrolysis was shown to be Mg2+ dependent within the low millimolar range but at 5 mM was inhibitory. In order to characterize the predicted domains of Bradeion &#914;, these defined regions were successfully expressed in E. cozi and purified. The CD spectrum of CF exhibited the shape typically found for non-regular structure. The results of fluorescence spectroscopy, gel filtration (SEC) and NMR-600MHz also corroborate with the CD results indicating an irregular structure. The fusion protein 6xHis-DGTPase exhibited a CD spectrum with the typical shape characteristic of the presence of helical elements but was show to be instable at high concentrations in the absence of imidazole. To characterize the GTPase activity of the fusion protein GST+DGTPase, the CE technique was used to monitor GTP hydrolysis. Analysis by CE showed that GST+DGTPase was functional, since both GTP and ATP hydrolysis was observed in a Mg2+ dependent manner. This work provides novel approaches, which should aid in the fbture study of the structure and fùnction of Bradeion &#913; e &#914;, others septins and related GTPases.

Os objetivos deste trabalho são avaliar o papel da atenção na percepção de tempo em jovens, idosos e pacientes com a doença de Alzheimer (DA). Nosso trabalho experimental consiste em 4 experimentos. Os experimentos 1 e 2 avaliaram a percepção de tempo em jovens, empregando tarefas de reprodução e de discriminação de durações temporais, respectivamente. Os resultados mostram um efeito atencional nas durações curtas com menor d. Os experimentos 3 e 4 compararam a percepção de tempo entre jovens, idosos e pacientes com DA, empregando tarefas de reprodução e de discriminação de tempo, respectivamente. Os resultados mostram um pior desempenho de idosos e pacientes com DA em relação aos jovens, que parece corresponder a uma deficiência atencional. Concluímos que a modulação da atenção apresenta papel fundamental e crítico na percepção de tempo e os déficits na percepção de tempo em idosos e em pacientes com DA parecem estar associada a uma menor quantidade de recursos atencionais ou a uma dificuldade de focar a atenção. / Our work focused on the attentional modulation of the perception of time. Additionally, other objective was to study the effect of aging and Alzheimers disease (DA) on temporal perception. We have performed four experiments. The first and the second experiments evaluated time perception in young volunteers, by means of the reproduction and discrimination of time intervals, respectively. The results showed an effect of attention on short durations, confirmed by d. The third and fourth experiments had the objective to compare time perception among young volunteers, elderly and DA patients, utilizing reproduction and discrimination of time intervals, respectively. Our findings showed a worse performance in both elderly volunteers and patients with DA in comparison with the group of young volunteers. Our conclusion is that time perception deficits in elderly and patients with DA are associated either to lesser attentional resources or to an increased difficulty in focusing attention on the target, which is more evident in patients suffering of DA.

RESUME Le paludisme, la maladie la plus dévastatrice des régions tropicales fait l’objet de nombreuses recherches ayant pour but de trouver des médicaments préventifs, du matériel de protection, de nouveaux traitements, des vaccins, … Notre travail s’est inscrit dans la recherche des composés naturels actifs sur l’agent pathogène, le Plasmodium. Nos investigations phytochimiques et pharmacologiques ont porté sur Triclisia sacleuxii, une plante utilisée en médecine traditionnelle pour traiter diverses maladies dont deux parasitaires: la schistosomiase et l’ascardiose. Elle est aussi employée dans la préparation du poison de flèche. De plus, T. sacleuxii appartient à la famille des Menispermaceae, une famille riche en alcaloïdes bisbenzylisoquinoléiques (BBIQ). Ces composés ont de nombreuses propriétés biologiques dont l’activité antipaludique et trypanocide. Plusieurs autres espèces appartenant au genre Triclisia sont utilisées en médecine traditionnelle pour traiter la fièvre, le paludisme et d’autres pathologies. Ces éléments ont motivé la recherche dans cette plante des composés à activité antiplasmodiale. En effet, la plupart des composés que nous en avons isolés (p 12) sont actifs aussi bien sur la souche chloroquino-sensible (3D7) que sur la souche chloroquino-résistante (W2) que nous avons testées. Deux d’entre eux ont en plus une activité plus élevée vis-à-vis de la souche choroquino-résistante. Les composés actifs sur Plasmodium falciparum ont également montré une toxicité à l’égard de Trypanosoma brucei brucei, une sous-espèce apparentée à celles qui sont à la base de la maladie du sommeil en Afrique Centrale et de l’Est. A part les usages mentionnés précédemment, T. sacleuxii est en plus employée comme antidote contre les morsures de serpents. Ce qui voudrait dire qu’elle pourrait renfermer des inhibiteurs d’enzymes. Aussi, des BBIQ ont déjà démontré une activité inhibitrice de l’acétylcholinéstérase (AChE) et des phospholipases A2. Sur base de ces informations, nous avons assigné un troisième objectif à notre investigation qui cible l’AChE en correlation avec la maladie d’Alzheimer (MA). La MA est une pathologie neurodégénérative qui affecte en général les personnes âgées de plus de 60 ans, caractérisée entre autres par une perte progressive de la mémoire, une détérioration de plusieurs fonctions cognitives, de troubles neurologiques et du comportement, … Les différents extraits alcaloïdiques ont montré un degré d’inhibition de l’AChE élevé ( 80 - 90%) à une concentration de 100 μg/ml. Avec les composés purs, l’inhibition est très variable (30 - 90 %) suivant la structure. Enfin, nous avons effectué des investigations pour déterminer le mode d’action antiplasmodiale des BBIQ majeurs isolés de T. sacleuxii. Il apparaît que non seulement toutes les BBIQ n’agissent pas par un même mode d’action, mais aussi un même composé pourrait agir simultanément suivant deux ou plusieurs mécanismes différents. SUMMARY Malaria, the most devastating disease in tropical areas, is currently a target of numerous researches, aiming to find preventive medicines, protective tools, new treatments and vaccines. In a search for antiplasmodial natural compounds, we have undertaken phytochemical and pharmacological investigations on Triclisia sacleuxii, used in traditional medicine to treat various ailments including two parasitological diseases; schistosomiasis and ascariasis. It is also used as an arrow poison. Triclisia sacleuxii belongs to the Menispermaceae family, which is known to contain bisbenzylisoquinolines. These components have shown various biological activities among which antimalarial and trypanocidal activity. Furthermore, many Triclisia species are used in traditional medicine for treating fever and malaria along with other disorders. With this background the research was set out to investigate on possible antiparasitic compounds active against Plasmodium falciparum. Most of the compounds isolated in this work were active towards both chloroquine sensitive strain (3D7) and chloroquine resistant Plasmodium strain (W2). Interestingly some of them demonstrated selectivity for the resistant strain. The compounds which displayed antiplasmodial activity also showed toxicity against Trypanosoma brucei brucei, a parasite related to those which cause sleeping sickness. Besides Triclisia sacleuxii traditional uses mentioned above, it is also used as a snakebites antidote. This suggests that it might contain enzymes inhibitors. Additionally, in previous works, bisbenzylisoquinolines which are believed to be present in T. sacleuxii, have displayed phospholipases A2 and acetylcholinesterase inhibitory activity. On the basis of these informations, the third aim of our investigation targeted acetylcholinesterase (AChE), an enzyme involved in Alzheimer’s disease (AD). AD is a neurodegenerative disease occurring mostly in people aged beyond 60 years, characterised by a progressive loss of memory, impairement of multiple cognitive functions, neurological and behavior disorders,.... Our results have demonstrated that leaves, stems and roots alkaloidal fractions have high anti-AChE activity. Pure compounds exhibited a structure-dependent activity ranging from 30 up to 90% at a concentration of 100μg/ml). Finally, we have undertaken an investigation on the antiplasmodial mode of action of the major alkaloids. It appears that not only the BBIQ do not act by a same mechanism, but also a single compound may act by more than one mode of action.

The aim of this doctoral thesis was to study the influence of memory, pain, age and education on the regional cerebral blood flow (rCBF), i.e. brain function, in early Alzheimer's disease (AD) and in chronic neck pain patients in comparison to healthy controls and in healthy elderly per se. This was done by optimizing single photon emission computed tomography (SPECT) as a method to study rCBF with the tracer Technetium-99m (99mTc) hexamethylpropyleneamine oxime (HMPAO) and by matching all image data to a brain atlas before evaluation. The rCBF-SPECT was evaluated and developed to obtain higher diagnostic accuracy in AD and in chronic neck pain patients it was used to study basic pain related cerebral processes in chronic pain of different origin. A new semimanual registration method, based on fiducial marker, suitable for investigations with low spatial resolution was developed. The method was used to reconstruct images with an improved attenuation and scatter correction by using an attenuation-map calculated from the patients' previously acquired CT images. The influence of age and education on rCBF was evaluated with statistical parametric mapping, SPM in healthy elderly. The main findings were age related changes in rCBF in regions close to interlobar and interhemispheric space but not in regions typically affected in early AD, except for the medial temporal lobe. The theory of a 'cognitive reserve' in individuals with a longer education was supported with findings in the lateral temporal lobe, a region related to semantic memory, and in the frontal lobe. A cross-sectional study of chronic neck pain patients showed extensive rCBF changes in coping related regions in a non-traumatic pain patients compared to both healthy and a pain group with a traumatic origin, i.e. whiplash syndrome. The whiplash group displayed no significant differences in rCBF in comparison with the healthy controls. This suggests different pain mechanisms in these groups. The AD-patients showed a significantly lower rCBF in temporoparietal regions including left hippocampus. These changes were associated to episodic memory performance, and especially to face recognition. The diagnostic sensitivity for AD was high. The face recognition test (episodic memory) was used in AD patients to improve the sensitivity of method, i.e. memory-provoked rCBF-SPECT (MP-SPECT). The results were compared to healthy controls and the reductions of rCBF in temporoparietal regions were more pronounced in mild AD during provocation. Memory provocation increased the sensitivity of AD-related rCBF changes at group level. If a higher sensitivity for AD at the individual level is verified in future studies, a single MP-SPECT study might then be of help to set diagnosis earlier. In conclusion rCBF in temporoparietal regions are associated to an impaired episodic memory in early AD. Changes in these regions do not have a strong connection to chronological age. The diagnostic sensitivity of rCBF-SPECT in AD is high and there is a potentially higher sensitivity if memory provoked investigations are used. The findings in this thesis have given an increased knowledge of underlying cerebral pain processing in non-traumatic and traumatic (whiplash) neck pain. Preliminary results supporting the theory of 'cognitive reserve' by showing a correlation between long education and preserved rCBF was found in healthy elderly.

Progression and pattern of changes in different biomarkers of Alzheimer’s disease (AD) and frontotemporal lobar degeneration (FTLD) like [18F]fluorodeoxyglucose positron emission tomography (FDG-PET) and magnetic resonance imaging (MRI) have been carefully investigated over the past decades. However, there have been substantially less studies investigating the potential of combining these imaging modalities to make use of multimodal information to further improve understanding, detection and differentiation of various dementia syndromes. Further the role of preprocessing has been rarely addressed in previous research although different preprocessing algorithms have been shown to substantially affect diagnostic accuracy of dementia. In the present work common preprocessing procedures used to scale FDG-PET data were compared to each other. Further, FDG-PET and MRI information were jointly analyzed using univariate and multivariate techniques. The results suggest a highly differential effect of different scaling procedures of FDG-PET data onto detection and differentiation of various dementia syndromes. Additionally, it has been shown that combining multimodal information does further improve automatic detection and differentiation of AD and FTLD.

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