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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.
491

Caractérisation d'un modèle d'infection cérébrale in utero par le cytomégalovirus chez le rat : conséquences post-natales et rôle de l'activation microgliale

Cloarec, Robin 17 December 2015 (has links)
L’infection par le cytomégalovirus (CMV) au cours de la grossesse est fréquente et représente la première cause de pathologie neurodéveloppementale. En dépit de cette importance médicale, il n’existe à ce jour aucun traitement préventif ou curatif satisfaisant, et les mécanismes physiopathologiques mis en jeu, en particulier au niveau du cerveau foetal, restent mal connus. Des découvertes récentes sur les modèles murins d’infection cérébrale par le CMV, principalement réalisées pendant la période néonatale, ont apporté des données convergentes sur la physiopathologie de ces infections cérébrales ; notamment, le rôle joué par les cellules immunitaires périphériques dans la résolution de l’infection, et l’implication du système immunitaire cérébral (SIC) au cours du processus infectieux. Afin de compléter et préciser les résultats précédemment obtenus dans différents modèles murins, et de comprendre le rôle joué par le SIC, le premier objectif de ma thèse a consisté à mettre au point et à caractériser un nouveau modèle d’infection cérébrale par le CMV au cours du développement in utero chez le rat. Dans l'ensemble, nos résultats confirment l'altération du SIC au cours de l'infection par le CMV du cerveau en développement, et suggèrent fortement, dans ce modèle, un rôle majeur joué par le système microglie/macrophage dans l'émergence de troubles neurologiques semblables à ceux observés dans la pathologie humaine correspondante. / Cytomegalovirus (CMV) infection during pregnancy is the leading cause of neurodevelopmental disorders (polymicrogyria, microcephaly) and may lead to severe sensorineural consequences (deafness, epilepsy, cerebral palsy and hearing loss). Despite this medical importance, no preventive or curative treatment is satisfactory to date, and the pathophysiological mechanisms, notably in the fetal brain, remain poorly understood. Recent findings in murine brain CMV infection, mostly in neonatal models, have brought converging insights into the pathogenesis of these infections; the possible role played by peripheral immune cells against infection and the involvement of the brain immune system (BIS) have been proposed. The actual roles of BIS during in utero infection, and more specifically that of microglial cells and macrophages, remain unclear. In order to expand and precise the data previously obtained in the murine models, and to clarify the role of BIS, the first objective of my thesis was to design and to characterize a novel model of CMV infection during the fetal development of the rat brain. Overall, our datas confirm the altered state of BIS as a consequence of CMV infection of the developing brain, and strongly suggest, in the rat model studied here, that the microglia/macrophages system plays critical role in the pathogenesis of neurological manifestations similar to those classically seen after human congenital CMV infection.
492

Conception et synthèse de nouveaux ligands du LDLR comme vecteurs ciblant le système nerveux central / Design of new peptidic ligands of the LDLR as potential blood-brain barrier targeting vectors for central nervous system drug delivery

Malcor, Jean-Daniel 15 December 2011 (has links)
La distribution de principes actifs dans le système nerveux central (SNC) est entravée par la présence d'une barrière physiologique, la barrière hémato-encéphalique (BHE). L'endothélium cérébral est pourvu d'un large éventail de systèmes de transport, parmi lesquels la trancytose récepteur-dépendante, qui peut être mise à profit pour vectoriser toute une gamme d'agents thérapeutiques vers le SNC de manière non invasive. Dans le cadre de cette approche, le LDLR (Low Density Lipoprotein Receptor), exprimé à la surface de la BHE, est une cible particulièrement intéressante. L'objectif de ce travail est le développement de nouveaux ligands du LDLR en tant que vecteurs potentiels de la BHE. Le criblage d'une librairie de peptides aléatoires dirigée contre le LDLR a permis l'identification d'un peptide 15-mer cyclique ayant une haute affinité in vitro. Une étude des relations structure/activité a ensuite été menée afin d'améliorer l'affinité pour le LDLR et d'augmenter la stabilité plasmatique de ce peptide. Cette étude a abouti à l'identification d'un nouveau peptide « lead » qui a été conjugué à des molécules actives afin d'évaluer la capacité du peptide à vectoriser un principe actif à travers la BHE après administration in vivo chez la souris. / Drug delivery to the central nervous system (CNS) is hindered by the presence of a physiological barrier, the blood-brain barrier (BBB). The brain endothelium is endowed with a series of transport systems, including receptor-mediated transcytosis. This system can also be used to transport therapeutics into the brain as a non-invasive manner. Among receptors expressed on the BBB, the low density lipoprotein receptor (LDLR) is relevant as a drug delivery system. This project is dedicated to the development of new peptide-based ligands of LDLR as potential BBB-vectors. The screening of a random peptide library directed to the LDLR led to the identification of hits such as a cyclic 15-mer peptide with high in vitro affinity. A structure/activity relationship study was then carried out in order to improve its affinity towards the LDLR and to increase its plasmatic stability. This study led to the identification of a new lead peptide which was conjugated to bioactive compounds in order to assess the ability of our peptide to shuttle a drug across the BBB following in vivo administration in mice.
493

Synthèse et caractérisation d'un hydrogel d'alginamide pour la régénération de voies nerveuses lésées au sein du Système Nerveux Central chez le rat / Synthesis and caracterization Alginamide hydrogel for regenaration of injured nerves

Vallée, Frédéric 20 December 2007 (has links)
Ce travail avait pour objectif la synthèse d’hydrogels d’alginates stables dans le temps et leur évaluation comme support de régénération des voies nerveuses lésées du Système Nerveux Central. Différents dérivés amphiphiles de l’alginate de sodium ont été préparés en fixant chimiquement des chaînes alkyles en C12 à différents taux sur le squelette polymère par l’intermédiaire, soit de liaisons ester (alginates esters), soit de liaisons amide (alginamides) moins sensibles à l’hydrolyse. Le comportement en solution des alginamides a été étudié en termes de stabilité dans le temps, de solubilité, de comportement rhéologique, et de taux de gonflement, puis comparé à celui des alginates esters. Les alginamides ont montré des propriétés en solution différentes de celles des alginates esters, en particulier des contraintes critiques faibles, qui sont les conséquences de la formation d’agrégats liée à l’existence d’une réaction secondaire de réticulation chimique lors de la synthèse. Néanmoins, à des concentrations et taux de greffage appropriés, il est possible d’obtenir un réseau polymère tridimensionnel stabilisé par des associations hydrophobes et pouvant servir de pont de régénération pour l’application visée. L’étude in vivo conclut à l’absence de signe de régénération des voies nerveuses chez les animaux lésées sur une durée d’un an. Toutefois, cette étude a permis de valider la stratégie d’implantation d’un gel physique rhéofluidifiant et thixotrope, de définir des méthodes d’analyse des tissus post mortem en présence d’hydrogel, d’examiner la possibilité d’encapsuler un traitement pharmacologique et de définir un cahier des charges élargi de ce biomatériau (pH, stabilité, gonflement …) / The aim of this work was to synthesise alginate hydrogels, stable in time, and to evaluate their potential use as scaffolds for the damaged nerve regeneration in central nervous system. Various amphiphilic derivatives of sodium alginate were prepared by covalent attachment of alkyl chains (12 carbons) onto the polysaccharide at different substitution ratio, either via ester (alginate ester) or amide (alginamide) linkages, these last ones being more stable toward hydrolysis. The properties in solution of the alginamide derivatives were studied in terms of solubility, stability as function of time, rheological behaviour and swelling ratio. Results were compared to those obtained with the alginate ester family and highlighted a different behaviour for the alginamide series in semi-dilute regime. In particular, alginamide hydrogels exhibited a low critical strain which has been attributed to the presence of aggregates in the solution. The formation of these aggregates was due to the occurrence of a secondary cross-linking reaction during the synthesis of polymers. Nevertheless, it was possible, by appropriate tuning of the substitution yield and of the solution concentration, to obtain a three-dimensional network stabilized by intermolecular hydrophobic interactions, which has been evaluated as regenerative support for the considered application. In vivo studies demonstrated the absence of nerve regeneration for the tested injured animals after one year. However, these studies allowed us to evaluate both the strategy for the implantation of a physical gel exhibiting a shear-thinning and thixotrope behavior and the possibility to encapsulate a pharmacological treatment. An enlarged project specification has also been defined for this biomaterial (pH, stability, swelling ratio…)
494

Avaliação da atividade antinociceptiva e anti-inflamatória do citronelol em roedores / Evaluation of the antinociceptive and anti-inflamatory activity of citronellol in rodents

Brito, Renan Guedes de 01 February 2013 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The Citronellol (CT) is an alcoholic monoterpene present in the essential oil of some medicinal plants such as Cymbopogon citratus. Some pharmacological effects such as the antispasmodic and anticonvulsant activities have been described, however it s possible antinociceptive and anti-inflammatory effect is unknown. Thus, the objective of this study was to evaluate the possible antinociceptive and anti-inflammatory action of CT in rodents. Therefore, 362 male Swiss mice (25-35 g) with 2 to 3 months were used. The animals were divided into groups and were treated with CT (25, 50 and 100 mg/kg, i.p.), vehicle (saline solution 0.9% + Tween 80 0.2%, i.p.) or standard drug (i.p.). To evaluate the antinociceptive activity, the animals were submitted to the test of abdomnal constrictions induced by acetic acid (0.85%), the formalin test (1%) and hot plate test. In order to evaluate the effect of CT on orofacial nociception, it was conducted the orofacial test induced by formalin (2%), capsaicin and glutamate. Motor coordination was assessed using the motor coordination test (rota rod) and the spontaneous movement test. The anti-inflammatory activity was evaluated based on the model of carrageenan-induced pleurisy, making up the total leucocyte count. It was also quantified, by using ELISA, TNF-α and nitric oxide generation by macrophages. To determine the central action, the animals were treated with CT, in three doses, or vehicle and, after ninety minutes, were anesthetized, perfused, the brains removed and cut in a cryostat. The brain sections were subjected to immunofluorescence protocol for Fos protein. Results are expressed as mean ± SEM Differences between groups were analyzed by using one way ANOVA test, and followed by Tukey test. Values of p < 0.05 were considered statistically significant. Intraperitoneal administration of CT produced a significant decrease (p < 0.001) of the abdominal constrictions induced by acetic acid. In nociception induced by formalin, the pretreatment with CT caused a significant antinociceptive effect (p <0.01) in both phases of the test. In the hot plate test, the reaction time increased significantly at all doses of CT (p < 0.05 or p < 0.001), while its effect was antagonized by naloxone. In the three orofacial nociception tests, the CT produced a significant decrease (p <0.001) in the face-rubbing time of the orofacial region. No changes were observed in the motor coordination and in the spontaneous movement test. In the evaluation of anti-inflammatory activity, treatment with CT gave rise to a significant decrease (p < 0.01) in total number of leukocytes, decreasing (p < 0.05) the levels of TNF-α and nitric oxide in macrophages (p < 0.05). By immunofluorescence, it was found that CT is able to activate signicantly (p < 0.05) neurons of the olfactory bulb, the piriform cortex, the restrosplenial cortex and the periaqueductal gray. So, it can be concluded that CT has antinociceptive and anti-inflammatory activity and its action is mediated by central and peripheral mechanisms. / O Citronelol (CT) é um monoterpeno alcóolico presente no óleo essencial de algumas plantas medicinais, como o Cymbopogon citratus. Alguns efeitos farmacológicos tais como anti-espasmódico e atividade anticonvulsivante já foram descritos, sendo desconhecido seu possível efeito antinociceptivo e anti-inflamatório. Desta forma, o objetivo do presente estudo foi avaliar a possível ação antinociceptiva e anti-inflamatória do CT em roedores. Para tanto, foram utilizados 362 camundongos Swiss machos (25 a 35 g) com 2 a 3 meses. Os animais foram divididos em grupos e foram tratados com CT (25, 50 e 100 mg/kg; i.p.), veículo (solução salina 0,9% + tween 80 0,2%; i.p.) ou droga padrão (i.p.). Para avaliação da atividade antinociceptiva, os animais foram submetidos ao teste de contorções abdominais induzidas por ácido acético (0,85%), ao teste da formalina (1%) e ao teste da placa quente. Com o intuito de avaliar a ação do CT na nocicepção orofacial, foram realizados os testes de dor orofacial induzida por formalina (2%), capsaicina e glutamato. A coordenação motora dos animais foi avaliada através do teste da coordenação motora (rota rod) e do teste da movimentação espontânea. A atividade anti-inflamatória foi avaliada a partir do modelo de pleurisia induzido por carragenina, realizando-se a contagem de leucócitos totais. Foi quantificado, ainda, através do ensaio imunoenzimático ELISA, o TNF-α e a geração de óxido nítrico por macrófagos. Para determinar a ação central, os animais foram tratados com CT, nas três doses, ou veículo e, noventa minutos após, foram anestesiados, perfundidos, os cérebros extraídos e cortados em criostato. As secções cerebrais foram submetidas ao protocolo de imunofluorescência para proteína Fos. Os resultados foram expressos como média ± erro padrão da média. As diferenças entre os grupos foram analisadas por meio do teste de variância ANOVA, uma via, seguido pelo teste de Tukey. Valores de p < 0,05 foram considerados estatisticamente significantes. A administração intraperitoneal de CT produziu uma redução significativa (p < 0,001) das contorções abdominais. Na nocicepção induzida por formalina, o pré-tratamento com CT causou um efeito antinociceptivo significativo (p <0,01) em ambas as fases do teste. No teste da placa quente, o tempo de reação aumentou significativamente em todas as doses de CT (p < 0,05 ou p < 0,001), tendo seu efeito antagonizado pela naloxona. Nos três testes de nocicepção orofacial, o CT produziu uma redução significativa (p < 0,001) no tempo de fricção da região orofacial. Não foram observadas alterações no teste da coordenação motora e no teste da movimentação espontânea. Na avaliação da atividade anti-inflamatória, o tratamento com CT causou uma diminuição significativa (p < 0,01) no número total de leucócitos, diminuindo os níveis de TNF-α (p < 0,05) e de óxido nítrico em macrófagos (p < 0,05). Através da imunofluorescência, observou-se que o CT é capaz de ativar signicativamente (p < 0,05) neurônios do bulbo olfatório, do córtex piriforme, do córtex retroesplenial e da substância cinzenta periaquedutal. Conclui-se, assim, que o CT apresenta ação antinociceptiva e anti-inflamatória, tendo sua ação mediada por mecanismos centrais e periféricos.
495

Avaliação da ação profilática da vacina de DNA-hsp65 na neurotuberculose experimental / Evaluation of the prophylactic action of the DNA-hsp65 vaccine in neurotuberculosis experimental

Santos, José Gilmar Costa 04 March 2016 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Tuberculosis (TB) is caused by Mycobacterium tuberculosis and is a global public health problem and is considered one of the deadliest infectious diseases of the world. It is estimated that about one third of the world population is infected. TB in Central Nervous System (CNS) is one of the most severe forms of the disease, more common in children aged six months to five years old and among individuals with immunosuppression, particularly those with Acquired Immunodeficiency Syndrome (AIDS). Neurotuberculosis (NTB) is associated with a high rate of mortality in children and permanent neurological sequelae in many survivors. Currently, the way to prevent TB is BCG (Bacilo Calmette-Guérin) vaccination, however, it has limitations because it only protects children and only prevents severe forms of TB, besides presenting variable protection of 0-75%. This shows the need to develop a more effective vaccine to fight TB. One of the most promising alternatives for TB is the DNA-hsp65 vaccine, made of a plasmid DNA containing the gene encoding the heat shock protein 65 kDa of mycobacteria (M. leprae). Although, it has not studied the protective effect of DNA-hsp65 vaccine against TB in the CNS, which is the most severe form of the disease and compromises the neural tissue. Thus, we evaluated the prophylactic effect of DNA-hsp65 vaccine in experimental neurotuberculosis. C57BL/6 mice were used by three experimental groups, where one of them was immunized only with plasmideal pVAX vector (vector group) by intramuscular administration of three doses every two weeks, another group received only PBS (PBS group) and the third group DNA was immunized with hsp65-pVAX plasmideal (vaccinated group). Thirty days after the last dose, the animals of each group were challenged with H37Rv laboratorial strain of Mycobacterium tuberculosis intracerebroventricularly by stereotaxy. Thirty days after the challenge with the bacilli, the mice were sacrificed and their brains and lungs removed. These organs were analyzed using histological sections stained with hematoxylin and eosin. It was also determined amounts of colony forming units (CFU) present in the brains of animals in all groups. The results show that animals of the vaccinated group exhibited brain and lung with discrete lesions of the vector and PBS groups. Furthermore, we noticed a reduced number of bacilli in the brains of animals in the vaccinated group. Therefore, our results suggest that DNA-hsp65 vaccine (pVAX-hsp65) is promising in the prevention of injuries caused by bacillus in the CNS. / A tuberculose (TB) é causada pelo Mycobacterium tuberculosis e representa um problema de saúde pública global, sendo considerada uma das doenças transmissíveis mais mortais do mundo. Estima-se que cerca de um terço da população mundial esteja infectada. A TB no Sistema Nervoso Central (SNC) é uma das formas mais graves da doença, sendo mais incidente em crianças de seis meses a cinco anos de idade e entre os indivíduos com imunodepressão, particularmente os portadores da Síndrome da Imunodeficiência Adquirida (AIDS). A Neurotuberculose (NTB) está associada a uma alta taxa de mortalidade em crianças e permanentes sequelas neurológicas em muitos sobreviventes. Atualmente, a forma de prevenção à TB é a vacina BCG (Bacilo Calmette-Guérin), porém, a mesma apresenta limitações, pois protege apenas as crianças e previne somente as formas graves de TB, além de apresentar proteção variável de 0 a 75%. Isso aponta a necessidade do desenvolvimento de uma vacina mais efetiva para o combate da TB. Uma das alternativas mais promissoras para o combate da TB é a vacina de DNA-hsp65, constituída por um plasmídeo de DNA contendo o gene que codifica a proteína de choque térmico de 65 kDa de micobactéria (M. leprae). Ainda não foi estudado o efeito protetor da vacina de DNA-hsp65 contra a TB no SNC, que é a forma mais grave da doença e compromete o tecido neural. Dessa forma, avaliamos o efeito profilático da vacina de DNA-hsp65 na neurotuberculose experimental. Foram utilizados camundongos C57BL/6 através de três grupos experimentais, onde um deles foi imunizado apenas com o vetor plasmideal pVAX (Grupo Vetor) através da administração de três doses quinzenais intramusculares, outro grupo recebeu apenas PBS (Grupo PBS) e o terceiro grupo foi imunizado com o DNA plasmideal pVAX-hsp65 (Grupo Vacinado). Trinta dias após a última dose, os animais de cada grupo foram desafiados com a cepa laboratorial H37Rv de Mycobacterium tuberculosis via intracerebroventricular através de estereotaxia. Passados trinta dias do desafio com o bacilo, os camundongos foram sacrificados e foram removidos cérebro e pulmão. Esses órgãos foram analisados através de cortes histológicos corados com hematoxilina e eosina. Também foram determinadas as quantidades de unidades formadoras de colônias (UFC) presentes nos cérebros dos animais de todos os grupos. Os resultados demonstram que os animais do grupo vacinado apresentaram cérebro e pulmão com lesões mais discretas do que os grupos vetor e PBS. Além disso, percebemos um número reduzido de bacilos nos cérebros dos animais do grupo vacinado. Portanto, nossos resultados sugerem que a vacina de DNA-hsp65 (pVAX-hsp65) é promissora na prevenção das lesões causadas pelo bacilo no SNC. / São Cristóvão, SE
496

Análise do papel da prostaglandina E2 e seus receptores na proliferação e apoptose em glioma humano, e da expressão das enzimas COX-1, COX-2, mPGES-1, mPGES-2 e cPGES. / Analysis of the role of prostaglandin E2 receptors in the proliferation and apoptosis of human glioma, and expression of the enzymes COX-1, COX-2, mPGES-1, mPGES-2 and cPGES.

Andrew Silva da Cunha 01 November 2012 (has links)
Os gliomas são tumores do sistema nervoso central (SNC) que evoluem a partir das células da glia. O tipo mais frequente e mais agressivo destes tumores é conhecido como glioblastoma multiforme (GBM) e entre as características biológicas de agressividade associadas a esse tumor estão o seu rápido crescimento e ausência de apoptose. O seu prognóstico desfavorável está associado à dificuldade de tratamento dessas células, pois possuem resistência à quimioterapia e a radioterapia. A expressão gênica das enzimas ciclooxigenase-1 (COX-1), ciclooxigenase-2 (COX-2), prostaglandina E sintase-1 microssomal (mPGES-1), prostaglandina E sintase-2 microssomal (mPGES-2), prostaglandina E sintase citosólica (cPGES) e os produtos da síntese destas enzimas, incluindo a prostaglandina E1 (PGE1) e a prostaglandina E2 (PGE2) estão diretamente relacionados com a malignidade dos gliomas. A PGE1 e a PGE2 podem atuar de modo autócrino e parácrino, interagindo com suas células alvos através de ligação aos receptores da superfície celular que estão ligados a proteína G. Estes receptores são conhecidos como receptores EPs e dividem-se em quatro subtipos: EP-1, EP-2, EP-3 e EP-4 sendo que cada um deles ativa vias distintas de sinalização intracelular. Desta forma, este estudo teve por objetivo analisar in vitro o papel da PGE1, PGE2 e seus receptores na proliferação e apoptose em glioma humano, e a expressão das enzimas COX-1, COX-2, mPGES-1, mPGES-2 e cPGES. / Gliomas are tumors of the central nervous system (CNS) that evolve from glial cells. The most common and most aggressive form of these tumors is known as glioblastoma multiforme (GBM). The biological aggressiveness of GBM is associated with its rapid growth and lack of apoptosis. Its poor prognosis is strongly associated with the difficulty of treating these cells as they are resistant to chemotherapy and radiotherapy. The gene expression of the enzymes cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2), microsomal prostaglandin E synthase-1 (mPGES-1), microsomal prostaglandin E synthase-2 (mPGES-2), cytosolic prostaglandin E synthase (cPGES) and the products of the activity of these enzymes, including prostaglandin E1 (PGE1) and prostaglandin E2 (PGE2), are directly related to the malignancy of gliomas. PGE1 and PGE2 can act in an autocrine and paracrine manner, by interacting with their target cells via binding to cell surface receptors that are linked to G-proteins. These receptors are known as EP receptors and are divided into four subtypes: EP1, EP2, EP3 and EP4; each of which activates distinct intracellular signaling pathways. Therefore, this study aimed to analyze, in vitro, the role of PGE1, PGE2 and their receptors in the proliferation and apoptosis of human glioma and the expression of COX-1, COX-2, mPGES-1, mPGES-2 and cPGES.
497

Dynamics of Neuron-Specific Gene Expression During Development and in Response to Selective Lesions of the Rat Central Nervous System: A Dissertation

Melloni, Richard H. 01 April 1993 (has links)
Synapse development and injury-induced reorganization in the nervous system have been extensively characterized morphologically, although, relatively little is known regarding the molecular and biochemical events that underlie these processes. In an attempt to better understand, at the molecular level, the role of the expression of synaptic proteins during synapse establishment and regeneration, this dissertation examines the dynamics of expression of the neuron-specific gene synapsin I during development and in response to selective lesions of the rat central nervous system. Synapsin I is the best characterized member of a family of nerve-terminal specific phosphoproteins implicated in the regulation of neurotransmitter release. During development, the expression of synapsin I correlates temporally and topographically with synapse formation, and recent physiological studies by Lu et al., (1992) have suggested that synapsin I may participate in the functional maturation of synapses. To better understand the temporal relationship between synapsin I gene expression and particular cellular events during development, we have used in situhybridization histochemistry to localize synapsin I mRNA in the rat central and peripheral nervous systems throughout embryonic and postnatal development, and into the adult period. During development, from the earliest embryonic time point examined (E12), the expression of the synapsin I gene was detectable in both the rat central and peripheral nervous systems. While, in general, levels of synapsin I mRNAs were high in utero, synapsin I cDNA probes revealed specific patterns of hybridization in different regions of the embryonic nervous system. To precisely determine the temporal onset of expression of the synapsin I gene during neuronal development, we examined in detail the appearance of synapsin I mRNA during the well characterized postnatal development of the cerebellum and hippocampus. In both regions, the onset of synapsin I gene expression correlated with the period of stem cell commitment to terminal differentiation. In a second phase, in accord with prior analyses, synapsin I gene expression increases to a maximum for a given neuronal population during synapse formation. In the adult rat brain, our data demonstrates a widespread yet regionally variable pattern of expression of synapsin I mRNA similar to that seen at earlier time points, with noteworthy exceptions. The greatest abundance of synapsin I mRNA was found in the pyramidal neurons of the CA3 and CA4 fields of the hippocampus, and in the mitral and internal granular cell layers of the olfactory bulb. Other areas abundant in synapsin I mRNA were the layer n neurons of the piriform and entorhinal cortices, the granule cell neurons of the dentate gyrus, the pyramidal neurons of hippocampal fields CA1 and CA2, and the cells of the parasubiculum. In general, the pattern of expression of synapsin I mRNA paralleled those encoding other synaptic terminal-specific proteins, such as synaptophysin, VAMP-2, and SNAP-25. Then, to determine specifically how synapsin I mRNA levels are related to levels of synapsin I protein in the adult rat brain, we employed in situhybridization histochemistry and immunohistochemistry to examine in detail the local distribution of both synapsin I mRNA and protein in the hippocampus. In short, these data revealed differential levels of expression of synapsin I mRNA and protein within defined synaptic circuits of the rat hippocampus. Based on these data we hypothesized that locally high levels of synapsin I mRNA in neuronal somata may reflect the ability of the nervous system to respond to select enviromental stimuli and/or injury by producing longterm changes in synaptic circuitry. To test this hypothesis and to better understand the regulation and putative role of synapsin I gene expression in the development of functional synapses in the central nervous system, we first examined the developmental pattern of expression of the synapsin I gene; in dentate granule neurons of the dentate gyrus and their accompaning mossy fibers during the main period of synaptogenic differentiation in the rat hippocampus. The results of these studies indicate a significant difference between the temporal expression of synapsin I mRNA in dentate granule cell somata and the appearence of protein in their mossy fiber terminals during the posmatal development of these neurons. Next, to investigate the regulation and putative role of synapsin I gene expression during the restoration of synaptic contacts in the central nervous system, we examined the expression of the synapsin I mRNA and protein following lesions of hippocampal circuitry. These studies show marked changes in the pattern and intensity of synapsin I immunoreactivity in the dendritic fields of dentate granule cell neurons following perforant pathway transection. In contrast, changes in synapsin I mRNA expression in target neurons, and in those neurons responsible for the reinnervation of this region of the hippocampus, were not found to accompany new synapse formation. On a molecular level, both developmental and lesion data suggest that the expression of the synapsin I gene is tightly regulated in the central nervous system, and that considerable changes in synapsin I protein may occur in neurons without concommitant changes in the levels of its mRNA. From a functional standpoint, our results suggest that the appearance of detectable levels of synapsin I protein in developing and sprouting synapses does not reflect simply synaptogenesis, but coincides with the acquisition of function by those central synapses.
498

An individual patient data meta-analysis on characteristics, treatments and outcomes of Glioblastoma/ Gliosarcoma patients with metastases outside of the central nervous system

Pietschmann, Sophie, von Bueren, André O., Kerber, Michael J., Baumert, Brigitta G., Kortmann, Rolf-Dieter, Müller, Klaus January 2015 (has links)
To determine the characteristics, treatments and outcomes of patients with glioblastoma multiforme (GBM) or gliosarcoma (GS) and metastases outside of the central nervous system (CNS).
499

The cerebral surfactant system and its alteration in hydrocephalic conditions

Schob, Stefan, Lobsien, Donald, Friedrich, Benjamin, Bernhard, Matthias K., Gebauer, Corinna, Dieckow, Julia, Gawlitza, Matthias, Pirlich, Mandy, Saur, Dorothee, Bräuer, Lars, Bechmann, Ingo, Hoffmann, Karl-Titus, Mahr, Cynthia V., Nestler, Ulf, Preuß, Matthias January 2016 (has links)
Introduction: Pulmonary Surfactant reduces surface tension in the terminal airways thus facilitating breathing and contributes to host''s innate immunity. Surfactant Proteins (SP) A, B, C and D were recently identified as inherent proteins of the CNS. Aim of the study was to investigate cerebrospinal fluid (CSF) SP levels in hydrocephalus patients compared to normal subjects. Patients and methods: CSF SP A-D levels were quantified using commercially available ELISA kits in 126 patients (0±84 years, mean 39 years). 60 patients without CNS pathologies served as a control group. Hydrocephalus patients were separated in aqueductal stenosis (AQS, n = 24), acute hydrocephalus without aqueductal stenosis (acute HC w/o AQS, n = 16) and idiopathic normal pressure hydrocephalus (NPH, n = 20). Furthermore, six patients with pseudotumor cerebri were investigated. Results: SP AÐD are present under physiological conditions in human CSF. SP-A is elevated in diseases accompanied by ventricular enlargement (AQS, acute HC w/o AQS) in a significant manner (0.67, 1.21 vs 0.38 ng/ml in control, p<0.001). SP-C is also elevated in hydrocephalic conditions (AQS, acute HC w/o AQS; 0.87, 1.71 vs. 0.48 ng/ml in controls, p<0.001) and in Pseudotumor cerebri (1.26 vs. 0.48 ng/ml in controls, p<0.01). SP-B and SP-D did not show significant alterations. Conclusion: The present study confirms the presence of SPs in human CSF. There are significant changes of SP-A and SP-C levels in diseases affecting brain water circulation and elevation of intracranial pressure. Cause of the alterations, underlying regulatory mechanisms, as well as diagnostic and therapeutic consequences of cerebral SP''s requires further thorough investigations.
500

Identification of Neurotoxic Targets of Diverse Chemical Classes of Dietary Neurotoxins/Neurotoxicants

Rachel M Foguth (9343949) 16 December 2020 (has links)
<p>Neurological disorders are a major public health concern due to prevalence, severity of symptoms, and impact on caregivers and economic losses. While genetic susceptibility likely has a role in most cases, exposure to toxicants can lead to neurotoxicity, including potentially developmental origins of adult disease or increased risk of disease onset. These exposures are not necessarily large, acute exposures, but could accumulate, with a chronic low-dose exposure, causing toxicity. This research focuses on the potential neurotoxicity of two classes of dietary toxins/toxicants, heterocyclic aromatic amines (HAAs) and per- and polyfluoroalkyl substances (PFAS). HAAs, such as PhIP, harmane, and harmine, are formed in charred or overcooked meat, coffee, tobacco, and other foods. PFAS are largely used in making household materials, but are found in small amounts in eggs and dairy products and largely in contaminated water. While these two classes are diverse in terms of structure, common neurotoxic targets and mechanisms often exist. Therefore, we tested the effects of these chemicals on cell viability and neurotoxicity. In the first aim, we aimed to elucidate the mechanism of toxicity of harmane and harmine, focusing on their ability to cause mitochondrial dysfunction. The second aim was to determine the effects of either harmane or PhIP on the nigrostriatal motor systems and motor function of rats and mice, respectively. The third aim determined the effects of PFAS on neurodevelopment of Northern leopard frogs, focusing on changes in neurotransmitter levels and accumulation in the brain. Harmane did not cause motor dysfunction, but potentially affected the nigro-striatal motor system in an age- or sex-dependent manner. PhIP had differential effects on dopamine levels over time and caused motor dysfunction after subchronic exposure in mice. Perfluorooctane sulfonate (PFOS) accumulated in the brains of frogs and PFAS caused changes in neurotransmitter levels that were dose- and time-dependent. Overall, this research shows that toxins/toxicants humans are exposed to over their whole lives through their diet and contaminated water can cause neurotoxicity, potentially leading to or increasing risk of disease states. </p>

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