Τα τελευταία χρόνια μελετώνται εκτενώς οι μηχανισμοί της κυτταροφαγίας που εμπλέκονται στην άμυνα τόσο των θηλαστικών όσο και των εντόμων και οι οποίοι είναι συντηρημένοι εξελικτικά. Στο εργαστήριο της Βιολογίας Κυττάρου έχουν γίνει αρκετά και μεγάλα βήματα προς την κατεύθυνση της διερεύνησης του μηχανισμού της κυτταροφαγίας από τα αιμοκύτταρα των εντόμων, αλλά σίγουρα η πλήρης κατανόηση του μηχανισμού αυτού χρειάζεται πολλά πειράματα ακόμη. Πρόσφατα δεδομένα του εργαστηρίου μας φανέρωσαν πως το σύστημα ενεργοποίησης της προφαινολοξειδάσης στην επιφάνεια των αιμοκυττάρων, κατέχει κυρίαρχο ρόλο στην διαδικασία της κυτταροφαγίας. Η φαινολοξειδάση είναι το τελευταίο προϊόν του συστήματος ενεργοποίησης της προφαινολοξειδάσης. Συνθέτεται στα αιμοκύτταρα και παρουσιάζεται στην επιφάνεια των αιμοκυττάρων ως ανενεργό ζυμογόνο. Η αναστολή της δράσης της φαινολοξειδάσης έχει ως αποτέλεσμα μια σημαντική μείωση της κυτταροφαγίας. Η φαινολοξειδάση συμμετέχει επίσης στη διαδικασία της μελανοποίησης (μέσω της μετατροπής της τυροσίνης σε Dopa) και το σχηματισμό των οζιδίων ως μηχανισμού άμυνας. Τα δεδομένα αυτά, μας ώθησαν να μελετήσουμε αν η αποκαρβοξυλάση της Dopa που μετατρέπει την Dopa σε ντοπαμίνη, βρίσκεται και αυτή στην επιφάνεια των αιμοκυττάρων της μύγας της Μεσογείου και αν συμμετέχει στις διαδικασίες της κυτταροφαγίας, του σχηματισμό οζιδίων και της μελανοποίησης, που είναι μηχανισμοί εγγενούς άμυνας των εντόμων. Επίσης, μελετήσαμε και κατά πόσο η αιμολίνη, μια πρωτεΐνη αναγνώρισης μοριακών προτύπων που έχει δειχτεί ότι βρίσκεται σε ορισμένα λεπιδόπτερα, υπάρχει και στα αιμοκύτταρα της μύγας της Μεσογείου και συμμετέχει στην κυτταροφαγία των παθογόνων. / -

The byssal adhesion mechanism of the biofouling species Dreissena polymorpha was investigated using a combination of studies on synthetic peptide mimics of tandem repeat sequences from byssal component Dreissena polymorpha foot protein 1 (Dpfp-1) and characterization of the regions of the byssus. A 20-residue fusion peptide incorporating two Dpfp-1 repeat sequences adopts a random coil and β-turn conformation in solution, and spontaneously forms a film at the solid-liquid interface in the presence of iron (III) cations. Infrared characterization of the byssus Amide I region showed that β-sheets dominate its secondary structure, although the proportion of different secondary structures varies between regions. Matrix-assisted laser desorption ionization (MALDI) mass spectrometry of intact byssal regions identified previously unknown differences in the composition of byssal threads, plaques, and the adhesive interface, which are believed to correlate to the different roles of these components in the overall structure.

The byssal adhesion mechanism of the biofouling species Dreissena polymorpha was investigated using a combination of studies on synthetic peptide mimics of tandem repeat sequences from byssal component Dreissena polymorpha foot protein 1 (Dpfp-1) and characterization of the regions of the byssus. A 20-residue fusion peptide incorporating two Dpfp-1 repeat sequences adopts a random coil and β-turn conformation in solution, and spontaneously forms a film at the solid-liquid interface in the presence of iron (III) cations. Infrared characterization of the byssus Amide I region showed that β-sheets dominate its secondary structure, although the proportion of different secondary structures varies between regions. Matrix-assisted laser desorption ionization (MALDI) mass spectrometry of intact byssal regions identified previously unknown differences in the composition of byssal threads, plaques, and the adhesive interface, which are believed to correlate to the different roles of these components in the overall structure.

Parkinson’s disease is a common neurodegenerative disorder caused by nigrostriatal dopamine loss, with motor deficiencies as the primary outcome. To increase the striatal dopamine content, patients are treated with 3,4-dihydroxyphenyl-l-alanine (l-DOPA). Beneficial relief of the motor symptoms is achieved initially, although the efficacy is lost with time and severe side effects, referred to as l-DOPA-induced dyskinesia, manifest in the majority of patients. Biological mechanisms responsible for the dopaminergic degeneration and the upcoming of dyskinesia are still unclear, and thus knowledge regarding critical factors for maintenance of the nigrostriatal system as well as neurochemical changes upon chronic l-DOPA is urgent. The present work aims at studying the importance of glial cell line-derived neurotrophic factor (GDNF) for nigrostriatal preservation, and the involvement of the dopaminergic, serotonergic, and glutamatergic systems in l-DOPA-induced dyskinesia. Effects from different levels of GDNF expression were evaluated on fetal mouse nigrostriatal tissue in a grafting study. In GDNF gene-deleted grafts, degeneration of the entire nigrostriatal system was evident at 6 months. In grafts with partial GDNF expression, significant loss of dopamine neurons was observed at later time points, although deviant findings in the dopamine integrity such as reduced innervation capacity and presence of intracellular inclusions-like structures were already present at earlier stages. The results emphasize GDNF as a crucial factor for long-term maintenance of the nigrostriatal system. Furthermore, striatal neurochemical alterations upon chronic l-DOPA treatment were studied in hemiparkinsonian rats using in vivo voltametry. The findings demonstrated impaired dopamine as well as glutamate releases in dyskinetic subjects, with no effects from acute l-DOPA administration. Conversely, in l-DOPA naïve dopamine-lesioned animals, dopamine release was increased and glutamate release attenuated upon a l-DOPA challenge. Moreover, l-DOPA-derived dopamine release was demonstrated to originate from serotonergic nerve fibers in the dopamine-lesioned striatum, an event that contributes significantly to dopamine levels also in intact striatum, and thus, is not a consequence from dopamine depletion. Assessment of serotonergic nerve fibers in l-DOPA treated animals and in a grafting study concluded that nerve fiber density was not affected by chronic l-DOPA treatment, nevertheless, dysfunction of this system can be suspected in dyskinetic animals since dopamine release was impaired and regulation of glutamate release by serotonergic 5-HT1A receptor activation was achieved in normal but not in dyskinetic animals. Furthermore, the selective serotonin reuptake inhibitor, fluoxetine, attenuated l-DOPA-induced dyskientic behavior, an effect that was demonstrated to be mediated via 5-HT1A receptors. In conclusion, dysmodulation of multiple transmitter systems is evident in LID.

Thesis (Ph. D.)--State University of New York at Binghamton, Department of Psychology, Behavioral Neuroscience, 2008. / Includes bibliographical references.

Thèse (M.Sc.) -- Université Laval, 1997. / Dans le titre, le chiffre et la lettre 2A sont en indice. Bibliogr.: f. 83-120. Publié aussi en version électronique.

Parkinson’s disease (PD) is the second most common neurodegenerative condition to affect humans, and is characterised by the loss of dopaminergic neurons from the substantia nigra pars compacta (SNpc) in the midbrain along with the deposition of abnormal aggregates of alpha-synuclein protein in the brain which are in the form of Lewy bodies. Dopaminergic neurons from the SNpc project into a large subcortical structure known as the striatum, and positron emission tomography (PET) studies have demonstrated the dysfunction of the dopaminergic system in the striatum of patients with PD. Furthermore, immunohistochemistry studies of the striatum have identified the degeneration of dopaminergic nerve terminals and inclusions of alpha-synuclein. An aggressive and early onset form of familial PD is caused by the G51D point mutation in alpha-synuclein (G51D/+). Clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) technology has been used to generate a novel and precise rat model of PD which has the G51D mutation in rat alpha-synuclein. Wild-type (WT) and G51D/+ rats were analysed over the course of ageing (5, 10/11 and 16/17 months of age) using histological experiments and L-3,4-dihydroxy-6-18F-fluorophenylalanine (18FDOPA) PET imaging in order to determine if G51D/+ rats have abnormalities of histological staining and dopaminergic function analogous to those identified in patients with PD. Histological experiments were optimised using WT rat tissue and then used immunohistochemistry for tyrosine hydroxylase (an enzyme involved in the synthesis of dopamine) to evaluate dopamine nerve terminal integrity in the striatum of WT and G51D/+ rats. In addition, immunohistochemistry for alpha-synuclein was used to evaluate staining for alpha-synuclein in cell bodies and the neuropil within the striatum of WT and G51D/+ rats. 18F-DOPA is a well validated PET radiotracer and has been used to investigate dopaminergic function in the striatum of rats. The enzyme aromatic L-amino acid decarboxylase converts 18F-DOPA to 6-18F-fluorodopamine, which is in turn incorporated into presynaptic vesicles, and then released into the synaptic cleft following neuronal activation. PET imaging experiments were first optimised using phantoms and WT rats, then the optimised protocols were applied to studies of WT and G51D/+ rats. Results from tyrosine hydroxylase immunohistochemistry at Bregma 0.00 mm identified a trend for decreased optical density of tyrosine hydroxylase staining in the striatum of 5 month G51D/+ rats compared with age-matched WT controls (p=0.15), and in 17 month G51D/+ rats compared with age-matched WT controls (p=0.10). Semi-quantitative analysis of alpha-synuclein immunohistochemistry indicated an increased abundance of alpha-synuclein positive cell somata in the striatum, and decreased punctate terminal staining in the neuropil of G51D/+ rats compared with age-matched WT rats. 18F-DOPA PET imaging experiments indicated a trend for decreased influx rate constant (Ki) of 18F-DOPA in the striatum of 5 month old G51D/+ rats compared with age-matched WT controls (p=0.08), and a trend for decreased distribution volume ratio (DVR) of 18F-DOPA in the striatum relative to the cerebellum of 16 month old G51D/+ rats when compared with age-matched WT controls (p=0.09). 18F-DOPA PET imaging experiments also identified a trend for a decreased effective distribution volume ratio (EDVR) of 18F-DOPA in the striatum relative to the cerebellum (p=0.09) and in turn indicated increased effective dopamine turnover (EDT) (p=0.13) in the striatum of 16 month old G51D/+ rats compared with age-matched WT rats. Therefore, the results indicated abnormalities of dopaminergic function, as well as tyrosine hydroxylase and alpha-synuclein staining in G51D/+ rats compared with age-matched WT controls, and this appeared to have some features of PD in humans. Indices of EDT indicated compensatory changes in dopaminergic function in the striatum of 16 month old G51D/+ rats compared with age-matched WT rats. Additional compensatory changes in dopaminergic terminal function and tyrosine hydroxylase protein expression may be evident in 11 and 10 month old G51D/+ rats respectively compared with age-matched WT rats. The G51D/+ rat model represents an interesting model for further studies such as the underlying pathophysiology of PD. However, the phenotype observed in G51D/+ rats appeared to be less severe than that which has been observed in humans with G51D type PD.

Orientador: Elizabeth Maria Aparecida Barasnevicius Quagliato / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-09T09:41:15Z (GMT). No. of bitstreams: 1 Letro_GraceHelena_M.pdf: 1107376 bytes, checksum: 2610b83b9b3ecd9abf6796d76098a728 (MD5) Previous issue date: 2007 / Resumo: A dor é uma queixa muito freqüente na doença de Parkinson (DP) podendo preceder o diagnóstico da doença. O objetivo deste trabalho foi avaliar a dor num grupo de pacientes com DP. Utilizou-se a subescala II, III, IV (item - A) do UPDRS, a classificação segundo o estágio da doença Hoehn & Yahr, a escala de Schwab & England nos períodos On e Off , o questionário de dor Mc Gill, o inventário de depressão de Beck e o Mini- Exame do Estado Mental para exclusão de pacientes com escore menor que 20. Esta casuística foi constituída por 20 mulheres e 30 homens. A média de início dos sintomas foi de 54,84 anos +/- 9,54. A média de tempo de doença foi de 8,06 anos +/- 4,77. A dor foi relatada durante a anamnese por 27 pacientes; 22 (44%) no período de exacerbação dos sintomas (Off) e 5 (10%) pacientes no período de melhora e exacerbação dos sintomas (On e Off). Os dados demonstraram que a dor na DP apresentou uma freqüência de 54% nos 50 pacientes avaliados. O aumento da dor no período Off foi relatado pelos pacientes, sendo a rigidez um fator importante para o aparecimento da mesma. Não houve associação entre dor:- e tremor no período Off, o tempo de doença, o estágio Hoehn & Yahr, a escala de Schwab & England , a depressão, a discinesia. Observou-se melhora da dor com levodopa em 16 (59,26%) dos pacientes / Abstract: Pain is a very frequent complaint in the Parkinson's disease (PD) being able to precede the diagnosis of the disease. The objective of our work was to evaluate pain in a group of patients with PD. To evaluate pain were used the subscale II,III,IV ( item-A) of the UPDRS, the Hoehn & Yahr staging, Schwab and England ADL Scale in the period On and Off, the Questionnaire of pain McGill , the Inventory of depression of Beck and the Mini Examination of the Mental State for exclusion of patients with lesser score that 20. We evaluate 50 patients with PD, 20 women and 30 men. The average of beginning of the symptoms was of 54, 84 years +/_ 9, 54.The mean of duration of disease was of 8, 06 years+/_4, 77. Excluding the secondary illnesses, pain was told by 27 patients during of the clinical history; 22 (44%) in the aggravation period and 5 (10%) in the period of improvement and aggravation of the symptoms (On and Off). We data had demonstrated that pain in the PD presented a frequency of 54% in the 50 evaluated patients. The increase of pain in the off period was told by our patients, being the rigidity an important factor for the appearance of the same one. There wasn¿t association between pain: and tremor in the Off period, duration of disease, Hoehn & Yahr staging, scale of Schwab & England, the depression, the diskynesia. Our data had confirmed the improvement of pain with the use of levodopa in 16 (59, 26%) patients / Mestrado / Neurologia / Mestre em Ciências Médicas

Summary. Despite its being the most efficacious drug for symptom reversal in Parkinson's disease (PD), there is concern that chronic levodopa (L-DOPA) treatment may be detrimental. In this paper we review the potential for L-DOPA to 1) autoxidize from a catechol to a quinone, and 2) generate other reactive oxygen species (ROS). Overt toxicity and neuroprotective effects of L-DOPA, both in vivo and in vitro, are described in the context of whether L-DOPA may accelerate or delay progression of human Parkinson's disease.

No description available.