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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Modulation of Nicotinic ACh-, GABA(a)- and 5-HT<sub>3</sub>-Receptor Functions by External H-7, a Protein Kinase Inhibitor, in Rat Sensory Neurones

Hu, Hong Zhen, Li, Zhi Wang 01 December 1997 (has links)
1. The effects of external H-7, a potent protein kinase inhibitor, on the responses mediated by γ-aminobutyric acid A type (GAGA(A))-, nicotinic acetylcholine (nicotinic ACh)-, ionotropic 5-hydroxytryptamine (5-HT3)-, adenosine 5'-triphosphate (ATP)-, N-methyl-D-aspartate (NMDA)- and kainate (KA)-receptors were studied in freshly dissociated rat dorsal root ganglion neurone by use of whole cell patch-clamp technique. 2. External H-7 (1-1000 μM) produced a reversible, dose-dependent inhibition of whole cell currents activated by GABA, ACh and 5-HT. 3. Whole-cell currents evoked by ATP, 2-methylthio-ATP, NMDA and KA were sensitive to external H-7. 4. External H-7 shifted the dose-response curve of GABA-activated currents downward without changing the EC50 significantly (from 15.0 ± 4.0 μM to 18.0 ± 5.0 μM). The maximum response to GABA was depressed by 34.0 ± 5.3%. This inhibitory action of H-7 was voltage-independent. 5. Intracellular application of H-7 (20 μM), cyclic AMP (1 mM) and BAPTA (10 mM) could not reverse the H-7 inhibition of GABA-activated currents. 6. The results suggest that external H-7 selectively and allosterically modulates the functions of GABA(A)-, nicotine ACh- and 5-HT3 receptors via a common conserved site in the external domain of these receptors.
22

Pamoplantar Pustulosis. Pathogenetic Studies with Special Reference to the Role of Nicotine

Hagforsen, Eva January 2001 (has links)
Palmoplantar pustulosis (PPP) is a chronic disease of unknown pathogenesis. Most of the patients were smokers. High prevalence of a number of autoimmune diseases was observed among the patients (thyroid disease 14%, gluten intolerance 8%, diabetes type 1 3%). Eosinophils and neutrophils were found in large numbers in the pustules. Massive infiltrates of lymphocytes and mast cells in the dermis below the pustule and an abnormal acrosyringial pattern indicate that the acrosyringium is the target for the inflammation. Immunofluorescence (IF) revealed decreased innervation of the sweat gland, outward migration of substance P-positive granulocytes in the acrosyringium and an increased number of contacts between mast cells and nerve fibres in the dermis. Distributions of choline acetyltransferase (ChAT) and acetylcholinesterase (AChE) were studied, since they regulate the level of acetylcholine, the main inducer of sweating. The most intense AChE-like immunoreactivity (LI) was observed in the acrosyringium in the lowest part of the stratum corneum, corresponding to the site of the pustule in PPP. ChAT-LI in granulocytes and AChE-LI in mast cells were demonstrated, which may have implications for inflammatory processes in general. Nicotinic acetylcholine receptors (nAChR) are activated by acetylcholine but also by nicotine. Immunohistochemstry of α-3 and α-7 subtypes of the nAChRs showed that the nAChR expression in healthy skin was influenced by smoking. A highly abnormal α-7 nAChR distribution in PPP skin was observed. The levels of nAChR antibodies were elevated in 42% of the PPP sera, and 68% of these sera gave specific endothelial IF in the papillary dermis in skin from non-smokers. Positive IF in the acrosyringium was also noted in skin from smokers. Conclusions: Smoking seems to induce up-regulation of an antigen in palmar skin. The results indicate that PPP is an autoimmune disease and that nicotine might have a role in the onset of the inflammation.
23

Studies on the extra-neuronal cholinergic system in HIV-1 infection

Aldbah, Zainab 01 1900 (has links)
L’acétylcholine (ACh) est un important neurotransmetteur qui est produit dans le système nerveux. Cependant, cette molécule est aussi produite par d’autres cellules non-neuronales du corps humain. Cette dernière est produite en abondance par les lymphocytes T CD4+, qui sont la cible principale du virus de l’immunodéficience humaine (VIH). ACh exerce ses effets sur les cellules par l’intermédiaire de ses récepteurs nicotiniques (n) et muscariniques (m) qui sont exprimés à la fois sur les cellules immunitaires et non immunitaires dans le corps. Il est bien connu que l’ACh a des effets anti inflammatoires sur les cellules immunitaires, et c’est le récepteur nicotinique qui est un joueur indispensable de cet effet. SLURP-1 (Secreted Ly6/uPAR-related Protein-1), est une autre molécule secrétée par les cellules T activées et d’autres cellules. Elle agit comme un ligand allostérique pour le récepteur α7, et module les effets de l'ACh sur les lymphocytes T. Il est peu connu comment ce système cholinergique extra-neuronal (ENCS) est régulé chez les individus infectés par le VIH. Nos résultats démontrent que le taux d'ACh et de SLURP-1 en circulation ne change pas significativement chez les sujets infectés par le VIH comparé aux témoins sains. Cependant, le niveau de ces médiateurs est plus élevé chez les sujets infectés à long termes non progresseur (LTNP), qui contrôlaient la réplication virale, depuis plus que sept ans, sans aucune thérapie. Il est tentant de spéculer que le niveau élevé de ces deux composantes de l'ENCS peut jouer un rôle dans leur capacité à contrôler la réplication du VIH. Les résultats de cette étude montrent que l’agoniste du récepteur α7 diminue, et que l’antagoniste de ce même récepteur augmente la réplication virale in vitro, dans les cellules activées par le phytohaemagglutinin (PHA). En outre, l'hémicholinium (HC-3), un composé qui inhibe la capacité des cellules à produire ACh en compétition avec leur absorption de choline, augmente la réplication virale. L'expression du récepteur α7 sur les lymphocytes T CD4 + provenant du sang périphérique, mais pas sur les monocytes, était significativement réduite (p <0,01) chez les individus infectés par le VIH, et elle n'a pas été entièrement restaurée par le traitement antirétrovirale (TAR). Tandis que l'expression du récepteur adrénergique β-2 a diminué significativement (p <0,01) sur les monocytes et les lymphocytes T CD4 + chez des individus infectés par le VIH. Ces cellules répondent à la norépinephrine via ce récepteur et l’ACh secrété. Dans l'ensemble, les résultats cette étude suggèrent que le VIH provoque une modulation significative des différentes composantes de l'ENCS chez les individus infectés par le virus. Ce système pourrait être manipulé pour réduire la réplication virale et l’inflammation chez ces patients. / Acetylcholine (ACh) is an important neurotransmitter produced in the nervous system. However, the molecule is also produced by non-neuronal cells in the body. CD4+ T cells, the main targets of HIV-1, produce it abundantly. ACh exerts its effects on cells via its nicotinic (n) and muscarinic (m) receptors that are expressed on both immune and non-immune cells in the body. ACh is well known to exert anti-inflammatory effects on immune cells. The main receptor that is indispensable for the anti-inflammatory effects of ACh is the α7 nicotinic receptor. Another molecule, secreted by activated T cells and by other cells is SLURP-1 (Secreted Ly6/uPAR-related Protein-1), which acts as an allosteric ligand for α7 and fine tunes the effects of ACh on T cells. Little is known as to how this extra-neuronal cholinergic system (ENCS) is regulated in HIV-infected individuals. Our results show that the circulating levels of ACh and SLURP-1 do not change significantly in HIV-infected individuals, as compared to the circulating levels in healthy controls. Interestingly, higher levels of these soluble mediators were detected in HIV-infected long-term non-progressors (LTNP) who control the viral replication for more than seven years without any chemotherapy. It is tempting to speculate that the increase in levels of these two soluble mediators of the ENCS present in HIV-infected LTNPs may play a role in their ability to control HIV replication. The results from this study show that an α7 agonist decreased HIV replication, whereas a receptor antagonist increased its replication in vitro in human PHA blasts. Furthermore, hemicholinium (HC-3), a compound that inhibits the ability of the cells to produce ACh, by competing with their uptake of choline, increases the viral replication. The expression of the α7 receptor on peripheral blood CD4+ T cells, but not on monocytes, was significantly reduced (p<0.01) in HIV-infected individuals, and it was not fully restored by antiretroviral therapy (ART). Interestingly, the expression of the β2 adrenergic receptor was decreased significantly (p<0.01) on both monocytes and CD4+ T cells in HIV-infected individuals. These cells respond to norepinephrine via this receptor and secrete ACh. Overall, the results of this study suggest that HIV causes significant modulation of different components of the ENCS in virus-infected individuals. This system could be manipulated to reduce viral replication and inflammation in these patients.
24

Vers un traitement de la maladie d'Alzheimer : synthèse de nouveaux ligands multi-cibles / Toward an innovative treatment of Alzheimer's disease : Design of novel multi-target directed ligands

Pons, Mégane 06 December 2019 (has links)
La maladie d’Alzheimer (MA) est une maladie neurodégénérative complexe caractérisée par une perte progressive de la mémoire et de la cognition. C’est la première cause de démence chez le sujet âgé et affecte environs 4.6 millions de personnes par an, selon un rapport de l’association « Alzheimer’s disease International », le nombre de patients pourrait s’élever à 135.5 millions en 2050. Du fait de sa complexité, la MA reste incurable et seuls 4 médicaments aux vertus palliatives dont 3 visant à inhiber l’acétylcholinestérase (AChE) ont reçu une autorisation de mise sur le marché à ce jour. L’approche multi-cible parait particulièrement adaptée du fait du grand nombre de cibles potentielles de la pathologie, et du caractère multifactoriel de la maladie. Cette approche consiste à associer sur une seule molécule, plusieurs pharmacophores afin qu’ils puissent agir simultanément sur différentes cibles impliquées dans le processus neurodégénératif. Dans ce contexte, en parallèle de la resynthèse d’un ligand multi-cible conjugué alliant un inhibiteur d’AChE (IAChE) et un antioxydant, deux nouvelles familles de ligands multi-cibles conjuguées, combinant un IAChE et un agoniste des récepteurs nicotiniques α7 (α7 nAChR) ont été conçues et leur synthèse abordée. Dans le cas de la première famille, le fragment ivastigmine a été choisi pour sa capacité à inhiber de manière pseudo-irréversible l’AChE et a été conjugué à un motif quinuclidine, un puissant agoniste des α7 nAChRs impliqués dans la MA. En combinant ces deux fragments, il a été observé que les propriétés biologiques in vitro de chaque pharmacophore étaient améliorées. La structure de la seconde famille est basée sur le Donepezil, un IAChE réversible de plus forte affinité, combiné au même motif quinuclidine que dans la série précédente. Si des intermédiaires avancés ont été obtenus, un ou deux étapes restent à finaliser pour finaliser la synthèse de cette troisième famille de MTDL. / Alzheimer’s disease (AD) is a complex neurodegenerative disease characterised by a progressive loss of memory and cognition. Nowadays, 4.6 million new patients are identified every year and according to the “Alzheimer’s diseases International” association, the number of patients could reach 135.5 million in 2050. Due to its complexity, AD remains uncurable and only 4 palliative drugs, of which 3 are acetylcholinesterase (AChE) inhibitors (AChEI), have been approved by FDA to date. AD being a multifactorial illness, with many potential targets involved in the pathology, the MTDL approach seems promising. This strategy associates in one single molecule, different pharmacophores (at least) acting on different targets involved in this CNS-related disorder. In this context, in parallel with the upscaled synthesis of a conjugated MTDL combining an AChEI inhibitor and an antioxidant, two new families of conjugated MTDLs associating an AChEI and a α7 nicotinic receptor (α7 nAChR) agonist have been investigated. The structure of the first family was based on a Rivastigmine scaffold, known to be a pseudo-irreversible AChE inhibitor, and a quinuclidine fragment, a potent α7 nAChR agonist. By combining these two fragments, it was brought to light that the in vitro biological properties were improved on both targets. The second family was based on a donepezil fragment, a more potent AChEI, and the same quinuclidine fragment than in the first family. Advanced intermediates have been obtained, and two last steps remain to be achieved for the completion of this third MTDL series.
25

Elucidating the Role of the α7 Nicotinic Receptor in the Etiology of Schizophrenia.

Chandley, Michelle Johnson 13 December 2008 (has links) (PDF)
The α7 subunit of the nicotinic receptor, a ligand gated ion channel with an affinity for nicotine, has long been implicated in the pathophysiology of schizophrenia due to the extremely high rate of smoking within the patient population. However, the exact role of the receptor has never fully been determined. In the following studies, various functions the receptor may assume in disease state are evaluated. There is a strong relationship between the immune system and schizophrenia, with the α7 subunit possibly serving as the link between the two. One of the following studies looks at the possibility of the receptor functioning as antigen in an autoimmune response. Blood sera of schizophrenic patients, as well as controls, were analyzed for the presence of antibodies to the α7 subunit of the nicotinic receptor. A sensitive ligand-based assay revealed schizophrenic patients could possess a pathogenic level of antibody that may exacerbate the degenerative nature of the disease, allowing for the possibility that receptor antibodies may serve as a contributing factor in the etiology of the disorder in at least a subset of patients. In other studies, the expression of the α7 receptor was investigated. Recombinant α7 receptor production has eluded researchers in non-mammalian species and this was the focus of our initial studies. In general, the lack of sufficient molecular recombinant techniques utilizing the receptor makes characterization of the α7 receptor and it's specific protein interactions difficult to evaluate. The regulatory mechanisms of the nicotinic receptor α7 subunit production and receptor formation have yet to be completely elucidated. Results in this investigation found a relationship between a functional CRE-element in the promoter region.
26

Relação quantitativa entre a estrutura química e o bloqueio da transmissão neuromuscular para série de brometos de [2-(4-benzamido)etil] benzildimetilamônio para-substituídos / Quantitative relationship between chemical structure and neuromuscular transmission blockade for series of [2- (4-benzamido) ethyl] benzyldimethylammonium bromide for para-substituted

Siqueira, Leonardo José Amaral de 07 December 2001 (has links)
Neste trabalho foi preparada uma série de onze brometo de 2-[(4-X-benzamido) etil]benzildimetilamônio, compostos I.1-I.11, série I, estruturalmente análogos à procainamida, não descritos na literatura. Os valores do coeficiente de partição, log Papp7.40, destes compostos foram determinados pelo método shake-flask e foram utilizados como parâmetro lipofílico experimental. Os valores de deslocamento químico do grupamento carbonila, &#948; 13 C=O, foram determinados e foram determinados cm um espectrómetro de ressonância magnética nuclear a 75 MHz. Adicionalmente, outros parâmetros físico-químicos foram retirados da literatura: &#960;, &#963;p, &#932;, R e MR4 ou obtidos por cálculo: log Pcalc e &#960;exp. Os valores da concentração inibitória média (IC50) capaz de reduzir a contração máxima a 50% no período de 15 minutos, foram determinados em preparações nervo frênico-músculo diafragma de camundongos. Para verificar a natureza e a contribuição relativa dos parâmetros físico-químicos frente ao bloqueio da transmissão neuromuscular foi feito uma análise de QSAR, obtendo-se equações, usando análise de regressão linear. As análises de QSAR sugerem uma dependência positiva da lipofilicidade para o bloqueio da transmissão neuromuscular expresso por pIC50, segundo o modelo proposto expresso pela equação: (Ver arquivo PDF). / In this work, a set of eleven 2-[(4-X-benzamido)ethyl]benzyl dimethylammonium bromide structurally related to procainamide was synthesized. The apparent partition coefficient values were determined by means of \"shake-flask method and were taken as lipophilic parameters. The carbonyl chemical shifts values were determined in methanol-d4 and taken as electronic parameters. Additionally, physicochemical parameters were either taken from literature: &#960;, &#963;p, &#932;, R e MR4 or calculated: log Pcalc and &#960;exp. The median inhibitory concentration values (IC50) able to reduce maximal contraction to 50% at 15 minutes was determined in phrenic nerve-diafragm muscle preparation of mices. In order to verify the nature and relative contribution of the physicochemical parameters to neuromuscular blockage, QSAR equations were derived using regression analysis. The obtained QSAR model, expressed by the equation below, suggest that lipophilicity term plays an important role to neuromuscular blockage. (See files PDF).
27

Νόσος του Parkinson και γνωστική δυσλειτουργία : συσχέτιση με τον κινητικό φαινότυπο και το γονίδιο της α4 υπομονάδας του νευρωνικού νικοτινικού υποδοχέα της ακετυλοχολίνης

Λύρος, Επαμεινώνδας 09 October 2009 (has links)
ΜΕΛΕΤΗ Α΄ Στόχος: Να διερευνηθεί αν ο κινητικός υπότυπος της αστάθειας κορμού και δυσχέρειας της βάδισης (ΑΚΔΒ) σχετίζεται με τη γνωστική δυσλειτουργία που εμφανίζουν οι ασθενείς με νόσο του Parkinson (NP) χωρίς άνοια. Μέθοδοι: Χορηγήσαμε μια συστοιχία επιλεγμένων νευροψυχολογικών δοκιμασιών σε δύο ομάδες μη ανοϊκών ασθενών με ήπια έως μέτριας βαρύτητας νόσο κατηγοριοποιημένους είτε στον υπότυπο της ΑΚΔΒ είτε σε υπότυπο μη ΑΚΔΒ, καθώς και σε μια ομάδα υγιών μαρτύρων. Οι ομάδες εξισώθηκαν κατά το δυνατόν όσον αφορά δυνητικούς συγχυτικούς παράγοντες που επηρεάζουν τις νευροψυχολογικές επιδόσεις. Αποτελέσματα: Δε διαπιστώθηκαν σημαντικές διαφορές μεταξύ των δύο ομάδων ασθενών στην επίδοση σε οποιαδήποτε από τις χορηγηθείσες νευροψυχολογικές δοκιμασίες. Παρόλα αυτά, σε σχέση με τους μάρτυρες υπήρξε μια τάση διαφοροποίησης ως προς το κυρίαρχο πρότυπο της γνωστικής δυσλειτουργίας. Η ομάδα με τον υπότυπο της ΑΚΔΒ είχε βραδύτερες επιδόσεις σε μια δοκιμασία ψυχοκινητικής ταχύτητας και γνωστικής ευελιξίας, ενώ η ομάδα με υπότυπο της νόσου μη ΑΚΔΒ είχε χειρότερες επιδόσεις στις μετρήσεις της λεκτικής μάθησης και της οπτικοχωρικής αντίληψης. Συμπεράσματα: Ο υπότυπος της ΑΚΔΒ δε συσχετίσθηκε με σοβαρότερα γνωστικά ελλείμματα και έτσι είναι πιθανό οι μηχανισμοί της γνωστικής δυσλειτουργίας να είναι, έως ένα ορισμένο βαθμό, κοινοί ανεξάρτητα από τον κινητικό υπότυπο της νόσου. ΜΕΛΕΤΗ Β Στόχος: Να διερευνηθεί αν υπάρχει συσχέτιση μεταξύ της ΝΡ και του γονιδίου CHRNA4, το οποίο κωδικοποιεί την α4 υπομονάδα του α4β2 νικοτινικού υποδοχέα της ακετυλοχολίνης (nAChR). Mέθοδοι: Στη μελέτη συμμετείχαν 100 ασθενείς με ΝΡ και 105 μάρτυρες, εξισωμένοι ως προς την ηλικία και το φύλο και ανήκοντες στην ίδια πληθυσμιακή ομάδα με τους ασθενείς. Ο γενετικός δείκτης που εξετάσθηκε είναι ένας μονονουκλεοτιδικός πολυμορφισμός στο 5ο εξόνιο του γονιδίου CHRNA4 (dbSNP rs1044396). Έγινε απομόνωση DNA γονιδιώματος από περιφερικό αίμα και ακολούθησε ανάλυση μεγέθους περιοριστικών τμημάτων μετά από αλυσωτή αντίδραση πολυμεράσης και κατάτμηση των προϊόντων αυτής με το ένζυμο Hha I. Μια υποομάδα 42 ασθενών υποβλήθηκαν επίσης σε λεπτομερή κλινική και νευροψυχολογική εκτίμηση. Η στατιστική ανάλυση για τη σύγκριση της συχνότητας των αλληλομόρφων και των γονοτύπων μεταξύ των ομάδων έγινε με τη δοκιμασία χ2, και τον ακριβή έλεγχο Fisher εάν έστω ένα κελί είχε n<5. Υπολογίστηκαν οι σχετικοί κίνδυνοι και τα κατά 95% διαστήματα αξιοπιστίας τους που αντιστοιχούσαν στα αλληλόμορφα και τους γονότυπους. Χρησιμοποιήθηκε η λογιστική ανάλυση παλινδρόμησης εάν ήταν απαραίτητη η προσαρμογή για την ηλικία ή το φύλο. Αποτελέσματα: Οι συχνότητες των γονοτύπων στην ομάδα των ασθενών (TT 34%; CT 58%; CC 8%) σε σύγκριση με τις συχνότητες των γονοτύπων στην ομάδα των μαρτύρων (TT 28.6 %; CT 47.6%; CC 23.8 %) παρουσίασαν στατιστικά σημαντική διαφορά (χ2 = 9.48, df = 2, p = 0.009). Η ομοζυγωτία CC συσχετίσθηκε με χαμηλότερο κίνδυνο παρουσίας της ΝΡ (CC vs φορείς T: OR = 0.28; 95% CI = 0.12–0.65; p = 0.002; στατιστική ισχύς 93.1%). Παρατηρήθηκε επίσης απόκλιση στην κατανομή των αλληλομόρφων μεταξύ των ασθενών και των μαρτύρων. Υπήρχε σημαντικά χαμηλότερη συχνότητα του αλληλόμορφου C μεταξύ των ασθενών (37%) σε σχέση με τους μάρτυρες (47.6%) (χ2 = 4.73; df = 1; OR=0.65; 95% CI = 0.44–0.96; p = 0.03). Η ανάλυση διαστρωμάτωσης έδειξε ότι η διαφορά στην κατανομή των γονοτύπων μεταξύ ασθενών και μαρτύρων ήταν στατιστικά σημαντική και συγκριτικά μεγαλύτερη στο θήλυ φύλο σε σχέση με το άρρεν φύλο και στους ασθενείς με εκδήλωση ΝΡ σε όψιμη ηλικία ( > 50 ετών) σε σχέση με αυτούς που εμφάνισαν πρώιμης έναρξης νόσο (< 50 ετών). Οι ασθενείς με ΝP που ανιχνεύθηκαν να φέρουν το γονότυπο CC και υποβλήθηκαν σε νευροψυχολογική αξιολόγηση έτειναν να έχουν καλύτερα διατηρημένες τις γνωστικές λειτουργίες που σχετίζονται με την προσοχή και την ταχύτητα επεξεργασίας των πληροφοριών. Συμπεράσματα: Η παρουσία του αλληλομόρφου C (dbSNP rs1044396) του γονιδίου CHRNA4 συνδέεται με μειωμένο κίνδυνο ΝΡ κατά 35%. Επίσης, τα άτομα με το γονότυπο CC εμφανίζουν σχεδόν τρισήμισυ (3,5) φορές χαμηλότερο κίνδυνο νόσου του Parkinson. Η ποικιλομορφία του γονιδίου CHRNA4 φαίνεται ότι σχετίζεται ιδιαίτερα με την επιρρέπεια εκδήλωσης της ΝΡ με ηλικιακά όψιμη έναρξη της νόσου, και επίσης με τις γνωστικές λειτουργίες των ασθενών χωρίς άνοια, ειδικά αυτές που εξαρτώνται από την προσοχή και την οπτικοκινητική αντίληψη. / Study A Aim: To investigate whether there is an association of the postural instability and gait difficulty (PIGD) motor subtype with cognitive dysfunction in non-demented Parkinson’s disease (PD) patients. Methods: We administered a battery of selected neuropsychological tests to assess attention, psychomotor speed, executive functions (set shifting ability and inhibitory control), visuospatial perception and visual constructive ability to two groups of non-demented patients with mild to moderate disease classified either as PIGD or as non-PIGD subtype and to a group of healthy controls. Groups were matched on potential confounders of neuropsychological performance. Results: No significant differences were revealed between the two groups of patients in the performance of any of the administered neuropsychological tests. However, relative to controls there was a tendency towards a differential pattern of cognitive dysfunction. The PIGD group had slower performance in a test of psychomotor speed and cognitive flexibility, whilst the non-PIGD group performed worse in measures of verbal learning and visuo-spatial perception. Conclusions: The PIGD subtype was not associated with more severe cognitive deficits and may to a certain extent share common mechanisms of cognitive dysfunction with non-PIGD subtypes. Study B Aim: to investigate whether there is an association between PD and a variation in the CHRNA4 gene coding for the α4 subunit, the primary subunit of the α4β2 brain nicotinic acetylcholine receptors. Methods: Patients (N=100) and controls (N=105), matched on the basis of sex, age and ethnicity, were genotyped for a single nucleotide polymorphism at cDNA position 1860 lying within the 5th exon of the CHRNA4 gene. DNA was extracted from peripheral blood samples and genotyping was done by PCR-based restriction fragment length polymorphism analysis. A subset of 42 patients also received detailed clinical and cognitive assessments. Comparisons of allele and genotype frequencies between groups were performed using the χ2 test, and the Fisher exact test if one cell had n<5. The relative risk for genotypes and alleles was estimated through calculation of odds ratios (ORs) with 95% confidence intervals (CIs). Logistic regression analysis was used if adjustment for age or sex was necessary. Results: The genotype frequencies in the patients group (TT 34%; CT 58%; CC 8%) vs. the genotype frequencies in the control group (TT 28.6 %; CT 47.6%; CC 23.8 %) demonstrated a statistically significant difference (χ2 = 9.48, df = 2, p = 0.009). CC homozygosity was associated with a lower risk of PD (CC vs T carriers: OR = 0.28; 95% CI = 0.12–0.65; p = 0.002). Also, the allelic distribution was significantly different between patients and controls. There was a significantly lower frequency of the C allele among the patients with PD (37%) as compared with the controls (47.6%) (χ2 = 4.73; df = 1; OR=0.65; 95% CI = 0.44–0.96; p = 0.03). Stratified analysis showed that the difference in the genotypic distribution between cases and controls was significant among females but did not reach significance among males. The frequency of CC homozygotes was also significantly lower in the group of patients with late onset PD than in the controls, but it was not significantly different between the early onset group of patients and the controls. CC homozygotes also tended to have better performance than T carriers on measures of attention and psychomotor speed (Trail Making Test part A and Symbol Digit Modalities Test). Conclusions: The presence of the C allele at SNP rs1044396 of the CHRNA4 gene is associated with a decreased risk for PD by 35%. Moreover, the CC genotype lowers the risk for PD by ~ 3.5 fold. Variation in the CHRNA4 gene may particularly influence susceptibility for late onset PD and further be associated with measurable effects on overt cognitive performance of yet not-demented PD patients, specifically the part loading on attentional capacities.
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Vers la synthèse de la (-) - gymnodimine A et études de relations structure-activité du coeur spiroimine / Toward the total synthesis of the (−)-gymnodimine A and relations between structure and activity of the spiroimine moiety

Duroure, Leslie 17 October 2011 (has links)
Les gymnodimines, les spirolides, les pinatoxines et les ptériatoxines constituent une famille de toxines d’origine marine de structures complexes, produites en faibles quantités par des microorganismes marins appelés dinoflagellés. Ces toxines sont connues pour bloquer les récepteurs nicotiniques de l’acétylcholine (nAChR) sans que leurs modes d’action ne soient connus avec précision. D’après les différents tests biologiques réalisés à ce jour, il semblerait que le motif spiroimine, commun à toutes ces molécules, soit le pharmacophore principal, indispensable pour toute activité inhibitrice. Le travail réalisé au cours de cette thèse s’est focalisé sur la synthèse du fragment spiroimine de la (–)-gymnodimine A, dans l’optique d’une étude pharmacologique de ces structures. Dans un premier temps, la création du centre quaternaire a été développée en utilisant la réaction Tsuji-Trost qui nous a donné de bons résultats en termes de rendement et d’excès énantiomérique. Au cours d’une approche sur des substrats modèles, une stratégie de fonctionnalisation originale de la chaîne allylique, mettant en jeu une métathèse croisée puis une oxydation, nous a permis d’atteindre l’intermédiaire spirolactone désiré. Après quelques étapes d’aménagements fonctionnels, une réaction de Staudinger nous a permis d’isoler les spiroimines attendues. Puis, dans la perspective d’une future synthèse totale, la réaction de Tsuji-Trost a été appliquée à des substrats plus fonctionnalisés. Dans un second temps, une allylation décarboxylante asymétrique à partir de Beta-cétoesters, nous a aussi permis de former le centre stéréogénique avec de bons rendements et excès énantiomériques. Une séquence rapide et efficace a été mise au point pour la synthèse de motifs spiroimines. Après une étape d’isomérisation, les composés ont été engagés dans une réaction de cycloaddition 1,3-dipolaire entre un alcène et une fonction azoture pour former les spiroimines souhaitées. La généralisation de la méthode a alors pu être débuté. Les trois spiroimines isolées au cours de ces travaux ont été évalués biologiquement sur les nAChRs, montrant un effet antagoniste, voire bloquant, selon les structures, de ces récepteurs. Leurs structures est beaucoup plus simple que celle de la GYM A et l’activité biologique est plus faible que la molécule naturelle. Toutefois, ces résultats montrent bien que le motif spiroimine est l’un des pharmacophore de la GYM A. / Gymnodimines, spirolides, pinatoxines and pteriatoxines constitute a family of marine toxins with complex structures. They are produced in small quantities by marine microorganisms called dinoflagelles. These toxins are known to block the nicotinic acetylcholine receptors (nAChR), but the exact mode of action remains to be determined. Different biological tests showed that the spiroimine moiety, common feature to all these molecules, is the main pharmacophore, indispensable for the inhibitive activity. This Ph.D. work has been focused on the synthesis of the spiroimine fragment of the (–)-gymnodimine A, for pharmacological studies of these structures. In a first part, the formation of the quaternary carbon was developped around the Tsuji-Trost reaction. Good yield and enantiomeric excess were obtained. During our work with modele substrate, an original approach was used to functionnalize the allyl chain. We realized a cross metathesis followed by an oxidative cleavage to form an aldehyde used to synthezise the wished spirolactone. After some functional arrangements, a Staudinger cyclisation has been involved to isolate the expected spiroimines. Then, Tsuji-Trost reaction was applied to more functionnalized substrates for a future total synthesis. In a second time, an asymmetric decarboxylative allylation from Beta-cétoesters, was used to form the stereogenic center with good yield and enantiomeric excess. A short synthetic route was developped for the synthesis of the spiroimine moiety. After an isomerisation of the allylic chain, compounds were involved in a 1,3-cycloaddition between an alcene and an azide to form the wished spiroimines. The generalization of the method was just begun. Three spiroimines were isolated and biologically evaluated on nAChRs. Their structure were simpler than GYM A but they show an antagonist effect and even a blocking effect according to the molecule. Their biological activities were lower than the natural product but these results show that spiroimine moiety is one of the pharmacophore of the GYM A.
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Synthèse totale du 13-desméthyle spirolide C / Total synthesis of 13-desmethyl spirolide C

Rambla, Matt 22 September 2015 (has links)
Les gymnodimines, les spirolides, les pinnatoxines et les ptériatoxines constituent une famille de toxines d’origine marine de structures complexes, produites en faibles quantités par des microorganismes marins appelés dinoflagellés. Ces toxines sont connues pour bloquer les récepteurs nicotiniques de l’acétylcholine (nAChRs) sans que leurs modes d’action ne soient connus avec précision. D’après les différents tests biologiques réalisés à ce jour, il semblerait que le motif spiroimine, commun à toutes ces molécules, soit le pharmacophore principal, indispensable pour toute activité antagoniste. Le 13 dem SPX est un composé qui appartient à la famille des toxines à imines cycliques. Sa structure complexe présente un cœur à imine cyclique original, un macrocycle possédant un motif bis-spiroacétal et un buténolide. Actuellement aucune synthèse totale de ce composé n’a été publiée. L’ensemble du travail présenté dans ce manuscrit a été consacré à des études pour synthétiser, d’une part, le cœur imine spirocyclique et d’autre part, à la préparation d’un intermédiaire avancé pour parvenir à la synthèse totale de ce composé.Dans un premier temps une étude méthodologique pour synthétiser des spiroimines simplifiées optiquement actives a été réalisée. Une approche originale et convergente à été développée reposant sur des réactions d’ADc asymétrique, d’isomérisation et de cycloaddition-[3+2] 1,3-dipolaire, à partir de substrats facilement accessibles.Dans un second temps nous avons exploré deux voies synthétiques pour parvenir à un intermédiaire avancé pour la synthèse du 13 SPX C. Pour ce faire, deux approches ont été envisagées. Seule la stratégie reposant sur des étapes d’addition-1,2 d’un nucléophile, suivie d’une cyclisation pour obtenir les composés spirocycliques puis hydrogénation par l’iridium(I) cationique a été abordée au cours de ces travaux. / Gymnodimines, spirolides, pinnatoxines and pteriatoxines constitute a family of marine toxins with complex structures. They are produced in small quantities by marine microorganisms called dinoflagellates. These toxins are known to block the nicotinic acetylcholine receptors (nAChR), but the exact mode of action remains to be determined. Biological tests have showed that the spiroimine moiety, the common feature of these molecules, is the main pharmacophore, essential for the antagonist activity. 13-dem SPX C belongs to the cyclic imine toxin family. Its complex structure shows an original cyclic imine core, a macrocycle that bears bis spiroketal moiety and a butenolide. Currently, no total synthesis of this toxin has been achieved. This Ph.D. work has been focused on methodological studies to synthesize cyclic imine core of 13-dem SPX C and on the synthesis of a very functionalized compound to reach 13-dem SPX C.In the first part, a methodological work to synthesize simple optically active spiroimines was achieved. This original 3 steps sequence was based on asymmetric ADc reactions, isomerization and 1,3-dipolar [3+2]-cycloaddition from easily accessible cycloketones.In the second time we imagined two synthetic ways to reach a highly functionalized moiety of 13-dem SPX C. Only the way that relies on 1,2-addition of nucleophile followed by a cyclization to get spirocyclic patterns and an iridium(I) catalyzed hydrogenation of endo alkene was tested.
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Avaliação farmacogenética em pacientes tratados com fármacos antitabagismo / Pharmacogenetic evaluation in patients treated with drugs for smoking cessation

Santos, Juliana da Rocha dos 07 April 2015 (has links)
Introdução: A grande variabilidade individual em resposta a fármacos antitabagismo sugere que tratamentos específicos podem ser mais efetivos em determinados subgrupos de fumantes. No contexto de medicina personalizada, o principal objetivo do presente estudo foi avaliar se polimorfismos nos genes CHRNA4, CHRNB2, CYP2B6 e ANKK1 estão associados com a resposta às terapias de cessação tabágica em pacientes provenientes de um programa de assistência ao fumante. Métodos: Estudo de coorte com 483 pacientes fumantes que receberam tratamento farmacológico (vareniclina, vareniclina e bupropiona, bupropiona em monoterapia ou coadministrada com terapia de reposição nicotínica). O sucesso na cessação tabágica foi considerado para os pacientes que completaram 6 meses de abstinência contínua. O teste de Fagerström para a dependência à nicotina (FTND) e o escore de consumo situacional Issa foram utilizados para avaliar a dependência à nicotina. Os polimorfismos CHRNA4 (rs1044396 e rs2236196), CHRNB2 (rs2072660 e rs2072661) e ANKK1 (rs1800497) foram genotipados pela análise da curva de melting e os polimorfismos CYP2B6 *9 (rs3745274), *4 (rs2279343), *5 (rs3211371) foram genotipados por restrição enzimática. Resultados: Os pacientes com o genótipo CC para o polimorfismo CHRNA4 (rs10443196) obtiveram menor taxa de sucesso no tratamento com vareniclina (29,5%) em comparação com os portadores dos genótipos CT ou TT (50,9%) (P=0,007; n=167). Os genótipos CT ou TT foram associados com maior odds ratio para o sucesso (OR=1,67; IC 95%=1,10-2,53; P=0,02), em um modelo multivariado. Os pacientes com o genótipo AA para o polimorfismo CYP2B6 (rs2279343) obtiveram maior taxa de sucesso no tratamento com bupropiona (48,0%) em comparação com portadores dos genótipos AG ou GG (35,5%) (P=0,05; n=237). O genótipo AA foi associado com maior odds ratio para o sucesso no tratamento (OR=1,92; IC 95%=1,08-3,42; P=0,03), em um modelo multivariado. Não foram observadas diferenças significativas nos escores FTND e Issa com relação aos polimorfismos estudados. Conclusão: Os polimorfismos CHRNA4 (rs1044396) e CYP2B6 (rs2279343) estão associados com a cessação tabágica em indivíduos tratados com vareniclina e bupropiona, respectivamente. Sugere-se que estes polimorfismos influenciam a resposta farmacológica e podem ser importantes para o desenho de uma farmacoterapia individualizada / Background: The large individual variability in response to drugs for smoking cessation suggests that specific treatments can be more effective in particular subgroups of smokers. In the context of personalized medicine, the main aim of the present study was to evaluate whether the CHRNA4, CHRNB2, CYP2B6 and ANKK1 polymorphisms are associated with response to smoking cessation therapies in patients from a smoker assistance program. Methods: This cohort study enrolled 483 smoking patients patients who received pharmacological treatment (varenicline, varenicline plus bupropion, bupropion in monoterapy or plus nicotine replacement therapy). Smoking cessation success was considered for patients who completed 6 months of continuous abstinence. Fagerström test for nicotine dependence (FTND) and Issa situational smoking scores were analyzed for nicotine dependence. The CHRNA4 (rs1044396 and rs2236196), CHRNB2 (rs2072660 and rs2072661) and ANKK1 rs1800497 polymorphisms were genotyped by high resolution melting analysis and the CYP2B6 *9 (rs3745274), *4 (rs2279343) and *5 (rs3211371) were genotyped by restriction fragment lenght polymorphisms. Results: Patients with CHRNA4 rs1044396 CC genotype had lower success rate in treatment with varenicline (29.5%) compared with carriers of CT or TT genotypes (50.9%) (P=0.007, n=167). The CT or TT genotypes were associated with higher odds ratio for success (OR=1.67, 95%CI=1.10-2.53, P=0.02), in a multivariate model. Patients with CYP2B6 rs2279343 AA genotype had higher success rate in treatment with bupropion (48.0%) compared with carriers of AG or GG genotypes (35.5%) (P=0.05, n=237). The AA genotype was associated with higher odds ratio for success (OR=1.92, 95%CI=1.08-3.42, P=0.03), in a multivariate model. We did not observe significant differences in the FTND and Issa scores according to the studied polymorphisms. Conclusion: The CHRNA4 rs1044396 and CYP2B6 rs2279343 are associated with smoking cessation in individuals on varenicline and bupropion terapies, respectively. We suggest that these polymorphisms influence the pharmacological response of these drugs and it might be important in the design of individualized pharmacotherapy

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