Είναι γνωστό ότι η άνοια σχετίζεται με την απώλεια μνήμης, έκπτωση γλωσσικών ικανοτήτων, έλλειψη αυτονομίας και απώλεια της προσωπικής ταυτότητας του ασθενούς. Στόχος της παρούσας εργασίας είναι να αναδείξει τη σχέση αμφισημίας- άνοιας και να διερευνηθεί η σκοπιμότητα ύπαρξης ενός μεθοδολογικού εργαλείου για την εκτίμηση και τη διερεύνηση της γλωσσικής έκπτωσης στη άνοια μέσα από την γλωσσική επεξεργασία των λεξικών σχέσεων (μεταφορών –ομωνυμίας- μετωνυμιών) και να παρουσιάζει το προφίλ των ασθενών αυτών. Στην πρώτη ενότητα παρουσιάζω γενικά στοιχεία για την νόσο της άνοιας αλλά και στοιχεία για τους κυριότερους τύπους της νόσου όσον αφορά την γλωσσική συμπεριφορά των ασθενών. Στην ενότητα αυτή αναφέρω επίσης βασικά διαγνωστικά εργαλεία που χρησιμοποιούνται ευρέως για τον προσδιορισμό της νόσου, ενώ αναλυτικότερα στοιχεία για τα εργαλεία που χρησιμοποιούνται και τις δομές που εξετάζουν παρατίθενται στο παράρτημα. Κλείνοντας την ενότητα καταλήγω στα οφέλη και την αναγκαιότητα ύπαρξης πρώιμης διάγνωσης. Στην δεύτερη ενότητα αναφέρομαι κυρίως στο νοητικό λεξικό και στην δυσκολία πρόσβασης των ασθενών με πιθανή άνοια σε αυτό. Επιπλέον υπάρχουν στοιχεία για την λεξική κατάκτηση, επιλογή και ανάκτηση των πληροφοριών και φαίνεται η σχέση νοητικού λεξικού – αμφισημίας. Στην τρίτη ενότητα παρουσιάζω το φαινόμενο της αμφισημίας από την θεωρητική άποψη αρχικά της γλωσσολογίας, πως κατακτώνται οι αμφίσημες λέξεις και επεξεργάζονται σε σχέση με την ηλικία και καταλήγω στην νευρική συσχέτιση των λεξικών αμφισημιών με συγκεκριμένες εγκεφαλικές περιοχές. Στο τέλος της παρούσας ενότητας παρουσιάζω ευρήματα/ συμπεράσματα από πλήθος ερευνών που αφορούν την λεξική αμφισημία με διαφορετικές μεθόδους για κάθε τύπο άνοιας. Στην τελευταία ενότητα παρουσιάζω τις βασικές υποθέσεις μου πως η χρήση των λεξικών σχέσεων θα μπορεί να αποτελέσει διαγνωστικό εργαλείο στην άνοια. Επίσης παρουσιάζω την κατασκευή και τα αποτελέσματα της πειραματικής διαδικασίας ανάμεσα σε τέσσερα διαφορετικά υποκείμενα (πασχόντων –υγειών) διαφορετικής παθολογίας και σοβαρότητας. Ακολουθεί τέλος το παράρτημα με στοιχεία που αφορούν την διαφοροδιάγνωση της νόσου βάσει αλγορίθμων με τα γνωστικά ελλείμματα όπως παρουσιάζονται από τους φροντιστές των ασθενών αλλά και παθολογικών συμπτωμάτων που παρουσιάζουν, ενώ σε πίνακα υπάρχουν τα γλωσσικά στοιχεία που βοηθούν επίσης στην διαφοροδιάγνωση των κυριότερων τύπων άνοιας και τα αποτελέσματα της πειραματικής διαδικασίας. / It is well known that dementia is associated with memory loss, impaired language skills, lack of autonomy and loss of patients’ independence. The aim of this paper is to highlight the connection between ambiguity and dementia, and to investigate the feasibility of a methodological tool to assess and investigate the linguistic deduction in dementia through the linguistic processing of lexical relations (metaphor-homonymy-metonymy) and present the profile of such patients. In the first section I present general information as well as the linguistic features of the main types of dementia. In this section there is also a report on the diagnostic tools which are widely used to identify the disease. More detailed information about the use of these diagnostic tools is listed in the Annex. At the end of this section there is evidence about the benefits and the importance of early diagnosis. The second section is mainly referred to the mental lexicon and the difficulty patients with probable dementia face in accessing it. Furthermore there is evidence for lexical acquisition, selection and retrieval of information which shows the mental lexicon – ambiguity connection. In the third section I present the phenomenon of ambiguity, starting from the theoretical linguistic view; how the ambiguous words are conquered and processed in relation to age and lead to neural correlation of lexical ambiguity with specific brain regions. At the end of this section I present findings / conclusions of several researches, using different methods, on the lexical ambiguity on each type of dementia. The last section presents my basic assumptions concerning how the use of lexical relations can be a diagnostic tool in dementia. Furthermore, I present the construction and the results of the experimental process between four different subjects (patient-healthy) with different pathology and severity of the disease. Finally, at the annex, I present data on the differential diagnosis of the disease based on algorithms with cognitive deficits reported by caregivers of patients as well as pathology features. Also there is a board with differential linguistic elements which help distinguish the main types of dementia, along with the experimental material used and the results of the procedure.

Parkinson’s disease (PD) is a neurodegenerative disorder that is characterised by a reduction of dopamine concentration in the striatum due to degeneration of dopaminergic neurons in the substantia nigra. Currently, first line treatment of PD includes the use of dopamine precursors, dopamine agonists and inhibitors of enzymatic degradation of dopamine, in an effort to restore dopamine levels and/or its effects. However, all these therapeutic strategies are only symptomatic and unfortunately do not slow, stop or reverse the progression of PD. From the discovery of adenosine A2A receptor-dopamine D2 receptor heteromers and the antagonistic interaction between these receptors, the basis of a new therapeutic approach towards the treatment of PD emerged. Adenosine A2A receptor antagonists have been shown to decrease the motor symptoms associated with PD, and are also potentially neuroprotective. The possibility thus exists that the administration of an adenosine A2A antagonist may prevent further neurodegeneration. Furthermore, the antagonism of adenosine A1 receptors has the potential of treating cognitive deficits such as those associated with Alzheimer's disease and PD. Therefore, dual antagonism of adenosine A1 and A2A receptors would be of great benefit since this would potentially treat both the motor as well as the cognitive impairment associated with PD. The affinities (Ki-values between 0.6 mM and 38 mM) of a series of 1,4-dihydropyridine derivatives were previously illustrated for the adenosine A1, A2A and A3 receptor subtypes by Van Rhee and co-workers (1996). These results prompted this pilot study, which aimed to investigate the potential of the structurally related 3,4-dihydropyrimidin-2(1H)-ones (dihydropyrimidones) and 2-amino-1,4-dihydropyrimidines as adenosine A1 and A2A antagonists. In this pilot study, a series of 3,4-dihydropyrimidones and 2-amino-1,4-dihydropyrimidines were synthesised and evaluated as adenosine A1 and A2A antagonists. Since several adenosine A2A antagonists also exhibit MAO inhibitory activity, the MAO-inhibitory activity of selected derivatives was also assessed. A modified Biginelli one pot synthesis was used for the preparation of both series of compounds under solvent free conditions. A mixture of a β- diketone, aldehyde and urea/guanidine hydrochloride was heated for an appropriate time to afford the desired compounds in good yields. MAO-B inhibition studies comprised of a fluorometric assay where kynuramine was used as substrate. A radioligand binding protocol described in literature was employed to investigate the binding of the compounds to the adenosine A2A and A1 receptors. The displacement of N-[3H]ethyladenosin-5’-uronamide ([3H]NECA) from rat striatal membranes and 1,3-[3H]-dipropyl-8-cyclopentylxanthine ([3H]DPCPX) from rat whole brain membranes, was used in the determination of A2A and A1 affinity, respectively. The results showed that both 3,4-dihydropyrimidones and 2-amino-1,4-dihydropyrimidines had weak adenosine A2A affinity, with the p-fluorophenyl substituted dihydropyrimidone derivative (1h) in series 1, exhibiting the highest affinity for the adenosine A2A receptor (28.7 μM), followed by the p-chlorophenyl dihydropyrimidine derivative (2c) in series 2 (38.59 μM). Both series showed more promising adenosine A1 receptor affinity in the low micromolar range. The p-bromophenyl substituted derivatives in both series showed the best affinity for the adenosine A1 receptor with Ki-values of 7.39 μM (1b) and 7.9 μM (2b). The pmethoxyphenyl dihydropyrimidone (1d) and p-methylpneyl dihydropyrimidine (2e) derivatives also exhibited reasonable affinity for the adenosine A1 receptor with Ki-values of 8.53 μM and 9.67 μM, respectively. Neither the 3,4-dihydropyrimidones nor the 2-amino-1,4- dihydropyrimidines showed MAO-B inhibitory activity. Comparison of the adenosine A2A affinity of the most potent derivative (1h, Ki = 28.7 μM) from this study with that of the previously synthesised dihydropyridine derivatives (Van Rhee et al., 1996, most potent compound had a Ki = 2.74 mM) reveals that an approximate 100- fold increase in binding affinity for A2A receptors occurred. However, KW6002, a known A2A antagonist, that has already reached clinical trials, has a Ki-value of 7.49 nM. The same trend was observed for adenosine A1 affinity, where the most potent compound (1b) of this study exhibited a Ki-value of 7.39 μM compared to 2.75 mM determined for the most potent dihydropyridine derivatives (Van Rhee et al., 1996). N6-cyclopentyladenosine (CPA), a known adenosine A1 agonist that was used as a reference compound, however had a Kivalue of 10.4 nM. The increase in both adenosine A1 and A2A affinity can most likely be ascribed to the increase in nitrogens in the heterocyclic ring (from a dihydropyridine to a dihydropyrimidine) since similar results were obtained by Gillespie and co-workers in 2009 for a series of pyridine and pyrimidine derivatives. In their case it was found that increasing the number of nitrogens in the heterocyclic ring (from one to two nitrogen atoms for the pyridine and pyrimidine derivatives respectively) increased affinity for the adenosine A2A and adenosine A1 receptor subtypes, while three nitrogen atoms in the ring (triazine derivatives) were associated with decreased affinity. It thus appears that two nitrogen atoms in the ring (pyrimidine) are required for optimum adenosine A1 and A2A receptor affinity. The poor adenosine A2A affinity exhibited by the compounds of this study can probably be attributed to the absence of an aromatic heterocyclic ring. The amino acid, Phe-168 plays a very important role in the binding site of the A2A receptor, where it forms aromatic - - stacking interactions with the heterocyclic aromatic ring systems of known agonists and antagonists. Since the dihydropyrimidine ring in both series of this pilot study was not aromatic, the formation of aromatic - -stacking interactions with Phe-168 is unlikely. In conclusion, the 3,4-dihydropyrimidone and 2-amino-1,4-dihydropyrimidine scaffolds can be used as a lead for the design of novel adenosine A1 and A2A antagonists, although further structural modifications are required before a clinically viable candidate will be available as potential treatment of PD. / MSc (Pharmaceutical Chemistry), North-West University, Potchefstroom Campus, 2014

A challenge for the clinical management of Parkinson's disease (PD) is the large within- and between-patient variability in symptom profiles as well as the emergence of motor complications which represent a significant source of disability in patients. This thesis deals with the development and evaluation of methods and systems for supporting the management of PD by using repeated measures, consisting of subjective assessments of symptoms and objective assessments of motor function through fine motor tests (spirography and tapping), collected by means of a telemetry touch screen device. One aim of the thesis was to develop methods for objective quantification and analysis of the severity of motor impairments being represented in spiral drawings and tapping results. This was accomplished by first quantifying the digitized movement data with time series analysis and then using them in data-driven modelling for automating the process of assessment of symptom severity. The objective measures were then analysed with respect to subjective assessments of motor conditions. Another aim was to develop a method for providing comparable information content as clinical rating scales by combining subjective and objective measures into composite scores, using time series analysis and data driven methods. The scores represent six symptom dimensions and an overall test score for reflecting the global health condition of the patient. In addition, the thesis presents the development of a web-based system for providing a visual representation of symptoms over time allowing clinicians to remotely monitor the symptom profiles of their patients. The quality of the methods was assessed by reporting different metrics of validity, reliability and sensitivity to treatment interventions and natural PD progression over time. Results from two studies demonstrated that the methods developed for the fine motor tests had good metrics indicating that they are appropriate to quantitatively and objectively assess the severity of motor impairments of PD patients. The fine motor tests captured different symptoms; spiral drawing impairment and tapping accuracy related to dyskinesias (involuntary movements) whereas tapping speed related to bradykinesia (slowness of movements). A longitudinal data analysis indicated that the six symptom dimensions and the overall test score contained important elements of information of the clinical scales and can be used to measure effects of PD treatment interventions and disease progression. A usability evaluation of the web-based system showed that the information presented in the system was comparable to qualitative clinical observations and the system was recognized as a tool that will assist in the management of patients.

No description available.

Ce travail porte sur des approches translationnelles dans les synucléinopathies notamment l’atrophie multisystématisée (AMS). Au-delà de leur rôle dans la régulation du glucose, l’insulin et l’insulin like growth factor-1 (IGF-1) ont des propriétés neurotrophiques. Des études ont montrées que la signalisation de l’insuline/IGF-1 est altérée dans la maladie d'Alzheimer et des données suggèrent l’altération de l’insuline/IGF-1 dans la maladie de Parkinson (MP) et l’AMS. Nous avons mis en évidence une résistance à l’insuline dans les neurones des patients MP et AMS ainsi que dans les oligodendrocytes chez les patients AMS.Mon travail a également consisté à cibler la troncation de l’α-synuclein (α-syn) comme cible thérapeutique. Nous avons démontré dans un modèle murin d’AMS que la diminution de l’α-syn tronquée permettait de réduire l’agrégation d’α-syn et la dégénérescence des neurones dopaminergiques.Enfin, nous avons étudié l’implication dans l’AMS des métalloprotéinases matricielles (MMP), des enzymes impliquées dans remodelage de la matrice, la démyélinisation, la troncation de l’α-syn et la perméabilité de la barrière hémato-encéphalique. Ce travail nous a permis de montrer une augmentation de l’expression et de l’activité de MMPs chez les patients AMS. Nous avons également montré que les cellules gliales sont la source de cette augmentation et que la MMP-2 est retrouvée dans les agrégats des patients AMS.Nous montrons ici de caractéristiques distinctes de l’AMS comme des altérations qui se produisent dans les oligodendrocytes. Nous présentons aussi VX-765 comme un candidat prometteur pour ralentir la progression de la pathologie dans un contexte de synucléinopathie. / This work focused on translational approaches in synucleinopathies and more specifically in multiple system atrophy (MSA). Beyond their role in glucose homeostasis, insulin/IGF-1 are neurotrophic factors in the brain. Studies have shown altered insulin/IGF-1 signalling in Alzheimer’s disease and data suggest impaired insulin signaling/IGF-1 in Parkinson's disease (PD) and MSA. The aim of my work was to characterize insulin/IGF-1 signalling in MSA and PD brain tissue. Both groups showed neuronal insulin resistance. Oligodendrocytes in MSA patients were also insulin resistant.In line with the translational approach, we also targeted α-synuclein (α-syn) truncation pharmacologically in MSA transgenic mice, which led to reduced α-syn aggregation and the protection of dopaminergic neurons.We also assessed the activity and distribution of matrix metalloproteinases (MMPs) in the brain of MSA patients compared to healthy controls. MMPs are involved in the remodelling of the extracellular matrix, demyelination, α-syn truncation and blood brain barrier permeability. We showed altered expression and activity of MMPs in two distinct structures in MSA brains. We were also able to show that glial cells were the source of increased MMPs and show a unique expression of MMPs in α-syn aggregates of MSA patients compared to PD, evidence that might hint at a mechanism that is differently altered between PD and MSA.We here show distinct pathological features of MSA such as key alterations occurring in oligodendrocytes, further supporting MSA as a primary oligodendrogliopathy. We also present VX-765 as a candidate drug for disease modification in synucleinopathies.

Η παρούσα εργασία αφορά στη μελέτη της ανταγωνιστικής αλληλεπίδρασης των Α1/D1 υποδοχέων στο επίπεδο έκφρασης του πρώιμου γονιδίου zif/268 (δείκτης νευρωνικής δραστηριότητας) και της in vivo μεταγωγής σήματος των Α1 και Α2Α υποδοχέων αδενοσίνης κάτω από τη ντοπαμινεργική απονεύρωση στο μυ weaver. Ο μυς weaver αποτελεί ένα γενετικό μοντέλο ντοπαμινεργικής απονεύρωσης, η οποία συμβαίνει σταδιακά, έτσι ώστε το μοντέλο αυτό να προσομοιάζει τη Νόσο Πάρκινσον (ΝΠ) στον άνθρωπο. Στο πρώτο στάδιο της μελέτης προέκυψε το ενδιαφέρον αποτέλεσμα ότι με την ταυτόχρονη ενεργοποίηση των Α1 και D1 υποδοχέων παρατηρήθηκε η αναμενόμενη ανταγωνιστική αλληλεπίδραση (ενδεχομένως μέσω σχηματισμού του ετεροδιμερούς), ενώ με την ενεργοποίηση μόνο των Α1 υποδοχέων στους weaver μύες παρατηρήθηκε αυξημένη ενεργοποίηση των νευρώνων του ραβδωτού σώματος και συγκεκριμένων περιοχών του εγκεφαλικού φλοιού. Η ενεργοποίηση αυτή ήταν μη αναμενόμενη, δεδομένου ότι οι Α1 υποδοχείς (A1Rs) είναι συζευγμένοι με Gi πρωτεΐνες και καταστέλλουν τη μεταγωγή σήματος που οδηγεί στην επαγωγή του zif/268 μέσω του D1R/Gs/cAMP/PKA/pDARPP-32/pCREB μονοπατιού. Η ακόλουθη διερεύνηση του μηχανισμού έδειξε ότι η Α1R-επαγόμενη ενεργοποίηση του zif/268 καταστέλλεται από τον ειδικό ανταγωνιστή των Α2Α υποδοχέων αδενοσίνης (A2ARs) ZM241385 και από τον ειδικό αγωνιστή των D2 υποδοχέων ντοπαμίνης Quinpirole, υποδεικνύοντας την ενεργοποίηση των Α2ΑRs και άρα ενεργοποίηση της έμμεσης οδού. Το αποτέλεσμα αυτό επιβεβαιώθηκε, δεδομένου ότι η διέγερση των Α1Rs προκάλεσε αύξηση της έκφρασης του mRNA της εγκεφαλίνης, αλλά όχι της δυνορφίνης, που αποτελούν δείκτες ενεργοποίησης της έμμεσης και της άμεσης οδού, αντίστοιχα. Το γεγονός ότι ο αγωνιστής των Α1Rs δεν προκαλεί στα φυσιολογικά ζώα ενεργοποίηση του zif/268 mRNA υποδεικνύει την υπερευαίσθητη απόκριση των Α2ARs. Η μελέτη της υπερευαίσθητης αυτής απόκρισης στο μυ weaver έγινε με τη διερεύνηση της μεταγωγής σήματος μετά από in vivo ενεργοποίηση των Α2ΑRs: α) του καθιερωμένου μονοπατιού Α2ΑRs/Gs/AC/cAMP/PKA/pDARPP-32/pCREB, το οποίο οδηγεί στη επαγωγή του zif/268 και β) του μονοπατιού των ΜΑΡΚ. Τα αποτελέσματα έδειξαν αυξημένα βασικά επίπεδα φωσφορυλίωσης της DARPP-32 στη θέση Thr-34. Τα αυξημένα επίπεδα της φωσφορυλιωμένης DARPP-32 πολλαπλασιάζουν τη δράση της ΡΚΑ και άρα διευκολύνουν τη μεταγωγή σήματος μέσω Α2ΑRs/Gs/AC/cAMP/PKA/pDARPP-32/pCREB μονοπατιού. Επομένως, η υπερευαίσθητη απόκριση των Α2ΑRs κάτω από την έλλειψη ντοπαμίνης στο μυ weaver φαίνεται να οφείλεται στα αυξημένα ενδογενή επίπεδα της φωσφορυλιωμένης DARPP-32. Ενδιαφέρον παρουσιάζει το γεγονός ότι τα βασικά επίπεδα φωσφορυλίωσης των πρωτεϊνών ERK1/2(MAPK44/42) είναι αυξημένα στον μυ weaver, αλλά μειώνονται σημαντικά μετά από την ενεργοποίηση των Α2ΑRs. Δεν γνωρίζουμε το μηχανισμό μέσω του οποίου αυξάνονται τα ενδογενή επίπεδα των ERK1/2 και πρέπει να διερευνηθεί περαιτέρω. Το συμπέρασμα όμως που εξάγεται είναι ότι κάτω από τη ντοπαμινεργική απονεύρωση η μεταβίβαση σήματος μέσω των Α2ΑRs δεν ενεργοποιεί την οδό των MAP κινασών. Στην παρούσα in vivo μελέτη αναδεικνύεται ο ρόλος των Α1 και Α2Α υποδοχέων στην λειτουργία των βασικών γαγγλίων κάτω από τη ντοπαμινεργική απονεύρωση. Τα αποτελέσματα αυτά έχουν ιδιαίτερη σημασία δεδομένου ότι εμφανίζονται σε ένα γενετικό μοντέλο παρκινσονισμού, στο οποίο η εκφύλιση των ντοπαμινεργικών νευρώνων είναι σταδιακή και προσομοιάζει τη ΝΠ, και όχι οξεία, όπως σε άλλα τοξικά μοντέλα. Επιπλέον, τα αποτελέσματα αυτά παρουσιάζουν ενδεχομένως κλινικό ενδιαφέρον, δεδομένου ότι η ενεργοποίηση της έμμεσης οδού μέσω Α1Rs από την ενδογενή αδενοσίνη θα επιδείνωνε περαιτέρω τις κινητικές δυσλειτουργίες της ΝΠ. Η πληροφορία αυτή, καθώς και η γνώση για την ενισχυμένη μεταγωγή σήματος μέσω των Α2Α υποδοχέων ενισχύουν την πρόταση για χρήση των Α2Α ανταγωνιστών ως αντιπαρκινσονικά φάρμακα. Δεδομένου ότι σήμερα το ενδιαφέρον είναι στραμμένο στη δημιουργία διμερών προσδεμάτων (bivalent ligands) που μπορούν να δρουν ταυτόχρονα σε δύο υποδοχείς, η συγκεκριμένη πληροφορία θα μπορούσε να χρησιμοποιηθεί για μελλοντική δημιουργία φαρμακευτικού σχήματος που να δρα ταυτόχρονα ως αγωνιστής των D2 υποδοχέων ντοπαμίνης και ως ανταγωνιστής των Α2Α υποδοχέων αδενοσίνης. / The present work studied the antagonistic interaction of A1/D1 receptors at the level of mRNA expression of the immediate early gene zif/268 (used as a marker of neuronal function). In parallel we studied the in vivo signal transduction of A1 and A2A adenosine receptors under dopamine deficiency in weaver mutant. The weaver mutant represents the only genetic animal model of gradual nigrostriatal neuron degeneration, which can be characterized as a pathophysiological phenocopy of Parkinson’s Disease. In the first part of the study, the co-activation of A1 and D1 receptors revealed the well-known antagonistic interaction of these receptors (possibly through the formation of A1/D1 heterodimer) in weaver mutant. An interesting result was that the activation of A1 receptors alone did induce zif/268 mRNA expression in stiatal and specific cortical neurons in weaver mutant. This induction was not expected, since A1 receptors are Gi-coupled and suppress the signal transduction pathway that leads to zif/268 induction through AC/PKA/p-DARPP-32/pCREB cascade. Further study, revealed that the A1 receptor-induced zif/268 mRNA expression is counteracted by the A2A receptor selective antagonist ZM241385 and by the D2 receptor selective agonist Quinpirole, suggesting the activation of A2A receptors and thus the activation of the “indirect pathway”. Moreover, A1 receptors activation induced the expression of enkephalin mRNA, but not of dynorphin, which are considered as marker of neuronal activation of the “indirect” and the “direct” pathway, respectively. The fact that the A1 receptor agonist did not induced zif/268 mRNA expression in +/+ animals indicates that under dopamine deficiency the A2A receptors react with a supersensitive response. This response was analyzed in weaver mouse after in vivo A2A receptor activation: a) by examining the classical signal transduction pathway of A2A receptors/AC/PKA/p-DARPP-32/pCREB, which leads to zif/268 expression and b) by studying the MAPK cascade. Results showed increased basal phosphorylation levels of DARPP-32 (dopamine- and cAMP-regulated phosphoprotein, MW 32kDa) of Thr-34 in weaver compared to control mice. Increased phosphoThr34-DARPP-32 would amplify the effects of the PKA and thus facilitating the signal transduction through A2A receptors/AC/PKA/p-DARPP-32/pCREB. Therefore, the A2A receptors supersensitive response under dopamine deficiency in weaver mutant seems to be due to elevated endogenous phosphorylation levels of DARPP-32. Interestingly, while the basal phosphorylation levels of ERK1/2 (MAPK44/42) are elevated in weaver mutant, they are significantly reduced after A2A receptor activation. Although we do not know the mechanism through which the endogenous ERK1/2 levels are elevated, the conclusion is that, under dopamine deficiency, A2A receptors do not activate MAPK cascade. The present in vivo study demonstrates the role of A1 and A2A adenosine receptors in the function of basal ganglia under dopamine deficiency. Our results are significant since the expreriments were performed in a genetic parkinsonian model, in which the dopaminergic neurons are gradually degenerated and thus simulate the human PD, and not in an acute toxic model. Moreover, these results could be of possible clinical relevance, since the activation of A1 receptors by endogenous adenosine would exaggerate the motor dysfunctions of PD. Furthermore, the enhanced signal transduction pathway through A2A receptors supports the suggestion that the A2A receptor antagonists as antiparkinsonian agents. Given the well-known A2A/D2 antagonistic interaction, new therapeutical prospectives would involve the development of pharmacological bivalent ligands, which can interact with the A2A/D2 receptors and act simultaneously as A2A receptor antagonists and as D2 receptor agonists.

Parkinson’s disease (PD) is a neurodegenerative disorder that is characterised by a reduction of dopamine concentration in the striatum due to degeneration of dopaminergic neurons in the substantia nigra. Currently, first line treatment of PD includes the use of dopamine precursors, dopamine agonists and inhibitors of enzymatic degradation of dopamine, in an effort to restore dopamine levels and/or its effects. However, all these therapeutic strategies are only symptomatic and unfortunately do not slow, stop or reverse the progression of PD. From the discovery of adenosine A2A receptor-dopamine D2 receptor heteromers and the antagonistic interaction between these receptors, the basis of a new therapeutic approach towards the treatment of PD emerged. Adenosine A2A receptor antagonists have been shown to decrease the motor symptoms associated with PD, and are also potentially neuroprotective. The possibility thus exists that the administration of an adenosine A2A antagonist may prevent further neurodegeneration. Furthermore, the antagonism of adenosine A1 receptors has the potential of treating cognitive deficits such as those associated with Alzheimer's disease and PD. Therefore, dual antagonism of adenosine A1 and A2A receptors would be of great benefit since this would potentially treat both the motor as well as the cognitive impairment associated with PD. The affinities (Ki-values between 0.6 mM and 38 mM) of a series of 1,4-dihydropyridine derivatives were previously illustrated for the adenosine A1, A2A and A3 receptor subtypes by Van Rhee and co-workers (1996). These results prompted this pilot study, which aimed to investigate the potential of the structurally related 3,4-dihydropyrimidin-2(1H)-ones (dihydropyrimidones) and 2-amino-1,4-dihydropyrimidines as adenosine A1 and A2A antagonists. In this pilot study, a series of 3,4-dihydropyrimidones and 2-amino-1,4-dihydropyrimidines were synthesised and evaluated as adenosine A1 and A2A antagonists. Since several adenosine A2A antagonists also exhibit MAO inhibitory activity, the MAO-inhibitory activity of selected derivatives was also assessed. A modified Biginelli one pot synthesis was used for the preparation of both series of compounds under solvent free conditions. A mixture of a β- diketone, aldehyde and urea/guanidine hydrochloride was heated for an appropriate time to afford the desired compounds in good yields. MAO-B inhibition studies comprised of a fluorometric assay where kynuramine was used as substrate. A radioligand binding protocol described in literature was employed to investigate the binding of the compounds to the adenosine A2A and A1 receptors. The displacement of N-[3H]ethyladenosin-5’-uronamide ([3H]NECA) from rat striatal membranes and 1,3-[3H]-dipropyl-8-cyclopentylxanthine ([3H]DPCPX) from rat whole brain membranes, was used in the determination of A2A and A1 affinity, respectively. The results showed that both 3,4-dihydropyrimidones and 2-amino-1,4-dihydropyrimidines had weak adenosine A2A affinity, with the p-fluorophenyl substituted dihydropyrimidone derivative (1h) in series 1, exhibiting the highest affinity for the adenosine A2A receptor (28.7 μM), followed by the p-chlorophenyl dihydropyrimidine derivative (2c) in series 2 (38.59 μM). Both series showed more promising adenosine A1 receptor affinity in the low micromolar range. The p-bromophenyl substituted derivatives in both series showed the best affinity for the adenosine A1 receptor with Ki-values of 7.39 μM (1b) and 7.9 μM (2b). The pmethoxyphenyl dihydropyrimidone (1d) and p-methylpneyl dihydropyrimidine (2e) derivatives also exhibited reasonable affinity for the adenosine A1 receptor with Ki-values of 8.53 μM and 9.67 μM, respectively. Neither the 3,4-dihydropyrimidones nor the 2-amino-1,4- dihydropyrimidines showed MAO-B inhibitory activity. Comparison of the adenosine A2A affinity of the most potent derivative (1h, Ki = 28.7 μM) from this study with that of the previously synthesised dihydropyridine derivatives (Van Rhee et al., 1996, most potent compound had a Ki = 2.74 mM) reveals that an approximate 100- fold increase in binding affinity for A2A receptors occurred. However, KW6002, a known A2A antagonist, that has already reached clinical trials, has a Ki-value of 7.49 nM. The same trend was observed for adenosine A1 affinity, where the most potent compound (1b) of this study exhibited a Ki-value of 7.39 μM compared to 2.75 mM determined for the most potent dihydropyridine derivatives (Van Rhee et al., 1996). N6-cyclopentyladenosine (CPA), a known adenosine A1 agonist that was used as a reference compound, however had a Kivalue of 10.4 nM. The increase in both adenosine A1 and A2A affinity can most likely be ascribed to the increase in nitrogens in the heterocyclic ring (from a dihydropyridine to a dihydropyrimidine) since similar results were obtained by Gillespie and co-workers in 2009 for a series of pyridine and pyrimidine derivatives. In their case it was found that increasing the number of nitrogens in the heterocyclic ring (from one to two nitrogen atoms for the pyridine and pyrimidine derivatives respectively) increased affinity for the adenosine A2A and adenosine A1 receptor subtypes, while three nitrogen atoms in the ring (triazine derivatives) were associated with decreased affinity. It thus appears that two nitrogen atoms in the ring (pyrimidine) are required for optimum adenosine A1 and A2A receptor affinity. The poor adenosine A2A affinity exhibited by the compounds of this study can probably be attributed to the absence of an aromatic heterocyclic ring. The amino acid, Phe-168 plays a very important role in the binding site of the A2A receptor, where it forms aromatic - - stacking interactions with the heterocyclic aromatic ring systems of known agonists and antagonists. Since the dihydropyrimidine ring in both series of this pilot study was not aromatic, the formation of aromatic - -stacking interactions with Phe-168 is unlikely. In conclusion, the 3,4-dihydropyrimidone and 2-amino-1,4-dihydropyrimidine scaffolds can be used as a lead for the design of novel adenosine A1 and A2A antagonists, although further structural modifications are required before a clinically viable candidate will be available as potential treatment of PD. / MSc (Pharmaceutical Chemistry), North-West University, Potchefstroom Campus, 2014

Parkinson’s Disease affects 10 million people worldwide, with 40% of patients developing an associated psychosis which has been identified by studies as the number one source of caretaker distress and is related to increased mortality. This is further complicated by the fact that typical antipsychotic drugs worsen many of the motor symptoms implicated in Parkinson’s Disease, with only one commercially available drug able to ameliorate both symptoms. This problem ushers the development of novel drugs to treat these symptoms, as first tested on research animals. Complicating matters, drug effectiveness on the degree of psychosis is hard to obtain in animals without a reliable biomarker. However, a hallmark of psychotic states is thought to be the reduced coordination between brain structures, through neuronal synchronization, as demonstrated by steady-state responses and is suggested to be a potential biomarker of psychosis. By building a MATLAB software we were able to analyze the degree of neural synchronization between structures, during an auditory steady-state response, in rats that had been unilaterally lesioned by the 6-Hydroxydopamine model of Parkinson’s Disease, before and after administration of the psychotomimetic drug MK801. These rats had been chronically implanted with 128-channel multi electrode array, enabling us to measure the strength of coherence between several limbic structures, associated with auditory processing, from the sampled local field potential, identifying the degree of synchronization in the animal brain. As our data demonstrate that coherence levels dropped in the psychotic drug state, for structures in both the healthy and the Parkinsonian hemisphere, we are able to further demonstrate the validity of coherence measures as a biomarker for psychosis. These results demonstrate that our software can be used as a tool to assess the therapeutic response of drugs developed, aimed at treating Parkinson’s associated psychosis. / Parkinsons sjukdom drabbar 10 miljoner världen över, där 40% av patienterna utvecklar en associerad psykos vilket har visats vara en av de största stressfaktorerna för deras vårdgivare och är även förknippat med en högre dödlighetsgrad. Denna situation förvärras av det faktum att de vanliga antipsykotiska drogerna kan förvärra många av de motoriska symptom som utgörs av Parkinsons sjukdom och det finns i dagsläget enbart en enda kommersiell drog som kan dämpa bägge symptom samtidigt. Detta problem frammanar vidare utveckling av nya läkemedel som kan behandla dessa symptom, som innebär att de först måste testas på försöksdjur. En komplikation som uppstår i relation till detta är svårigheten att utvärdera om läkemedel har någon terapeutisk effekt på de psykotiska tillstånden, enbart genom att observera försöksdjurens beteenden, och en pålitlig biomarkör krävs istället. En lösning kan dock finnas i det faktum att psykotiska tillstånd karaktäriseras av en reducerad förmåga för olika hjärnområden att koordinera genom neural synkronisering vilket demonstreras av ‘steady- state’ responser. Detta föreslår att ett mått på graden av koordineringsförmåga kan agera som en möjlig biomarkör för psykotiska tillstånd. Genom att konstruera ett MATLAB-program kunde vi analysera graden av synkronicitet mellan hjärnstrukturer, under den auditiva steady- state responsen i råttor som hade blivit ensidigt lesionerade genom 6-Hydroxiddopamin modellen av Parkinsons sjukdom, före och efter administration av den psykotomimetiska drogen MK801. Dessa råttor hade blivit kroniskt implanterade med 128 elektroder vilket möjliggjorde att vi kunde mäta styrkan i koherens i den lokala fält potentialen mellan limbiska strukturer, som är associerade med auditiv processering, vilket möjliggjorde identifiering av3dessa strukturers synkronicitet. Vår data demonstrerar att koherensen minskade under det psykotiska drogtillståndet för limbiska strukturer både i den intakta och den lesionerade hjärnhalvan. Detta är en vidare demonstration av att koherensnivåer kan agera som en biomarkör för det psykotiska tillståndet, liksom att vår mjukvara kan nyttjas som ett verktyg för att utvärdera nya läkemedels behandlingsförmåga på Parkinsons psykos.

Hypokinetická dysartrie (HD) je častým symptomem vyskytujícím se až u 90% pacientů trpících idiopatickou Parkinsonovou nemocí (PN), která výrazně přispívá k nepřirozenosti a nesrozumitelnosti řeči těchto pacientů. Hlavním cílem této disertační práce je prozkoumat možnosti použití kvantitativní paraklinické analýzy HD, s použitím parametrizace řeči, statistického zpracování a strojového učení, za účelem diagnózy a objektivního hodnocení PN. Tato práce dokazuje, že počítačová akustická analýza je schopná dostatečně popsat HD, speciálně tzv. dysprozodii, která se projevuje nedokonalou intonací a nepřirozeným tempem řeči. Navíc také dokazuje, že použití klinicky interpretovatelných akustických parametrů kvantifikujících různé aspekty HD, jako jsou fonace, artikulace a prozodie, může být použito k objektivnímu posouzení závažnosti motorických a nemotorických symptomů vyskytujících se u pacientů s PN. Dále tato práce prezentuje výzkum společných patofyziologických mechanizmů stojících za HD a zárazy v chůzi při PN. Nakonec tato práce dokazuje, že akustická analýza HD může být použita pro odhad progrese zárazů v chůzi v horizontu dvou let.

This work deals with a design of hypokinetic dysarthria analysis system. Hypokinetic dysarthria is a speech motor dysfunction that is present in approx. 90 % of patients with Parkinson’s disease. The work is mainly focused on parameterization techniques that can be used to diagnose or monitor this disease as well as estimate its progress. Next, features that significantly correlate with subjective tests are found. These features can be used to estimate scores of different scales like Unified Parkinson’s Disease Rating Scale (UPDRS) or Mini–Mental State Examination (MMSE). A protocol of dysarthric speech acquisition is introduced in this work too. In combination with acoustic analysis it can be used to estimate a grade of hypokinetic dysarthria in fields of faciokinesis, phonorespiration and phonetics (correlation with 3F test). Regarding the parameterization, features based on modulation spectrum, inferior colliculus coefficients, bicepstrum, approximate and sample entropy, empirical mode decomposition and singular points are originally introduced in this work. All the designed techniques are integrated into the system concept in way that it can be implemented in a hospital and used for a research on Parkinson’s disease or its evaluation.