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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.
151

Dietary Levels of Pure Flavonoids Improve Spatial Memory Performance and Increase Hippocampal Brain-Derived Neurotrophic Factor

Rendeiro, C., Vauzour, D., Rattray, Marcus, Waffo-Téguo, P., Mérillon, J.M., Butler, L.T., Williams, C.M., Spencer, J.P.E. 28 May 2013 (has links)
Yes / Evidence suggests that flavonoid-rich foods are capable of inducing improvements in memory and cognition in animals and humans. However, there is a lack of clarity concerning whether flavonoids are the causal agents in inducing such behavioral responses. Here we show that supplementation with pure anthocyanins or pure flavanols for 6 weeks, at levels similar to that found in blueberry (2% w/w), results in an enhancement of spatial memory in 18 month old rats. Pure flavanols and pure anthocyanins were observed to induce significant improvements in spatial working memory (p = 0.002 and p = 0.006 respectively), to a similar extent to that following blueberry supplementation (p = 0.002). These behavioral changes were paralleled by increases in hippocampal brain-derived neurotrophic factor (R = 0.46, p<0.01), suggesting a common mechanism for the enhancement of memory. However, unlike protein levels of BDNF, the regional enhancement of BDNF mRNA expression in the hippocampus appeared to be predominantly enhanced by anthocyanins. Our data support the claim that flavonoids are likely causal agents in mediating the cognitive effects of flavonoid-rich foods.
152

Growth factor concentrations in platelet-rich plasma for androgenetic alopecia: an intra-subject, randomized, blinded, placebo-controlled, pilot study

Siah, T.W., Guo, H., Chu, T., Santos, L., Nakamura, H., Leung, G., Shapiro, J., McElwee, Kevin J. 27 January 2020 (has links)
Yes / Background: Platelet rich plasma (PRP), processed from autologous peripheral blood, is used to treat androgenetic alopecia (AGA). Objective: To determine the efficacy of PRP for hair growth promotion in AGA patients in a randomized, blinded, placebo controlled, pilot clinical trial (NCT02074943). Methods: The efficacy of an 8 week, 5 session, PRP treatment course was determined by measuring hair density and hair caliber changes in 10 AGA affected patients. For each PRP sample, the concentrations of selected growth factors were determined using a multiplex assay system. The clinical results were then correlated to the growth factor concentrations in PRP. Results: At 16 weeks, 8 weeks after the last PRP injection, treated areas exhibited increased mean hair density (+12.76%) over baseline compared to placebo (+0.99%). Mean hair caliber decreased in both treated and placebo regions (-16.22% and -19.46% respectively). Serial analysis of PRP significant variability in concentrations between patients. Overall, there was a positive correlation between GDNF concentration and hair density (p= 0.004). Trends, though not statistically significant, were also observed for FGF2 and VEGF. Limitations: Small sample size and lack of comparative cohorts receiving protocol variations limit confidence in the study data. Conclusions: This small pilot clinical trial suggests PRP treatment may be beneficial for AGA. However, the variable hair growth responses between patients indicate there is a significant opportunity to improve PRP therapy protocols for hair growth promotion. The variability in growth factor concentration in PRP suggests standardization of growth factors post-processing might improve hair growth responses. / RepliCel Life Sciences Inc. (Canada)
153

On pathophysiological mechanisms in amyothrophic lateral sclerosis

Grundström, Eva January 2000 (has links)
<p>Amyotrophic lateral sclerosis is a fatal, progressive neurodegenerative disease with unknown ethiology. The aim of this study was to increase understanding of the pathophysiological mechanisms of dying motor neurons and wasting muscle tissue in this particular disorder.</p><p>Quantitative receptor autoradiographic methodology was applied on cervical spinal cord sections from patients with ALS to evaluate the specific binding of the acetylcholine transporter <sup>3</sup>H-vesamicol in motor neurons. Despite a significant reduction of the number of ventral motor neurons in ALS, the <sup>3</sup>H-vesamicol binding was not reduced in ALS compared to control cases, which suggests an increased metabolic activity in remaining motor neurons.</p><p>Motor neurons dying in ALS might go through apoptosis (programmed cell death), so immunohistochemical and TUNEL techniques were applied on thoracic spinal cord from ALS patients to evaluate the possibility of an apoptotic process. The increased Bax expression indicates an apoptotic process and further, motor neurons were TUNEL-positive, indicating DNA degradation caused by programmed cell death.</p><p>Muscle biopsies were obtained from ALS patients, and mRNA levels for the neurotrophic factors GDNF and BDNF were measured and compared to control subjects. GDNF levels were increased in muscle tissue in ALS whereas BDNF levels were unaltered.</p><p>Levels of GDNF and BDNF were also measured in cerebrospinal fluid from ALS patients and controls using ELISA methodology. Levels of BDNF were unaltered in ALS cornpared to controls. GDNF however was not detectable in controls whereas 12 out of 15 ALS patients had measurab1e levels of GDNW. A marked upregulation of endogenous GDNF and GDNF mRNA in ALS CSF and muscle respectively is of special interest in relation to clinical trials where GDNF is administered to this group of patients.</p>
154

On pathophysiological mechanisms in amyothrophic lateral sclerosis

Grundström, Eva January 2000 (has links)
Amyotrophic lateral sclerosis is a fatal, progressive neurodegenerative disease with unknown ethiology. The aim of this study was to increase understanding of the pathophysiological mechanisms of dying motor neurons and wasting muscle tissue in this particular disorder. Quantitative receptor autoradiographic methodology was applied on cervical spinal cord sections from patients with ALS to evaluate the specific binding of the acetylcholine transporter 3H-vesamicol in motor neurons. Despite a significant reduction of the number of ventral motor neurons in ALS, the 3H-vesamicol binding was not reduced in ALS compared to control cases, which suggests an increased metabolic activity in remaining motor neurons. Motor neurons dying in ALS might go through apoptosis (programmed cell death), so immunohistochemical and TUNEL techniques were applied on thoracic spinal cord from ALS patients to evaluate the possibility of an apoptotic process. The increased Bax expression indicates an apoptotic process and further, motor neurons were TUNEL-positive, indicating DNA degradation caused by programmed cell death. Muscle biopsies were obtained from ALS patients, and mRNA levels for the neurotrophic factors GDNF and BDNF were measured and compared to control subjects. GDNF levels were increased in muscle tissue in ALS whereas BDNF levels were unaltered. Levels of GDNF and BDNF were also measured in cerebrospinal fluid from ALS patients and controls using ELISA methodology. Levels of BDNF were unaltered in ALS cornpared to controls. GDNF however was not detectable in controls whereas 12 out of 15 ALS patients had measurab1e levels of GDNW. A marked upregulation of endogenous GDNF and GDNF mRNA in ALS CSF and muscle respectively is of special interest in relation to clinical trials where GDNF is administered to this group of patients.
155

Functional Investigations into the Recognition Memory Network, its Association with Genetic Polymorphisms and Implications for Disorders of Emotional Memory / Das Wiedererkennensgedächtnis: Untersuchung eines funktionellen neuronalen Netzwerkes im Zusammenhang mit genetischen Polymorphismen und deren Bedeutung für Störungen des emotionalen Gedächtnisses.

Dörfel, Denise 27 July 2010 (has links) (PDF)
Recent research, that has been focused on recognition memory, has revealed that two processes contribute to recognition of previously encountered items: recollection and familiarity (Aggleton & Brown, 1999; Eichenbaum, 2006; Eichenbaum, Yonelinas, & Ranganath, 2007; Rugg & Yonelinas, 2003; Skinner & Fernandes, 2007; Squire, Stark, & Clark, 2004; Wixted, 2007a; Yonelinas, 2001a; Yonelinas, 2002). The findings of neural correlates of recollection and familiarity lead to the assumption that there are different brain regions activated in either process, but there are, to the best of my knowledge, no studies assessing how these brain regions are working together in a recollection or a familiarity network, respectively. Additionally, there are almost no studies to date, which directly searched for overlapping regions. Therefore, in study I of the current thesis, brain regions associated to both recognition processes are searched investigated. Additionally, a connectivity analysis will search for functional correlated brain activations that either build a recollection or a familiarity network. It is undoubtable that the Brain Derived Neurotrophic Factor (BDNF) is strongly involved in synaptic plasticity in the hippocampus (Bramham & Messaoudi, 2005) and there is evidence that a genetic variant of this neurotrophin (BDNF 66Met) is related to poorer memory performance (Egan, et al., 2003). Therefore, in study II of the current thesis, the effect of BDNF Val66Met on recollection and familiarity performance and related brain activations is investigated. Finally, one could summarize, that serotonin, like BDNF, is strongly involved in brain development and plasticity as well as in learning and memory processes (Vizi, 2008). More precisely, there is evidence for alterations in the structure of brain regions, which are known to be involved in emotional memory formation and retrieval, like amygdala and hippocampus (Frodl, et al., 2008; Munafo, Brown, & Hariri, 2008; Pezawas, et al., 2005). One study found an slight epistatic effect of BDNF and 5-HTTLPR on the grey matter volume of the amygdala (Pezawas, et al., 2008). Therefore, in study III, it is investigated if such an interaction effect could be substantiated for the amygdala and additionally revealed for the hippocampus. The results of the current thesis allow further comprehension of recollection, hence episodic memory, and point to a special role of the BDNF in temporal and prefrontal brain regions. Additionally, the finding of an epistatic effect between BDNF and serotonin transporter function point to the need of analyzing interactions between genes and also between genes and environmental factors which reveals more information than the study of main effects alone. In conclusion, analyzing behavioral and neural correlates of episodic memory reveal allowed insights in brain functions that may serve as guideline for future studies in clinical populations with memory deficits, including susceptibility factors such as good or bad environment, as well as promising gene variants that influence episodic memory.
156

Specificity of neurotrophins in the nervous system : a genetic approach to determine receptor engagement by neurotrophins /

Agerman, Karin, January 2003 (has links)
Diss. (sammanfattning) Stockholm : Karol. inst., 2004. / Härtill 4 uppsatser.
157

Functional Investigations into the Recognition Memory Network, its Association with Genetic Polymorphisms and Implications for Disorders of Emotional Memory

Dörfel, Denise 22 January 2010 (has links)
Recent research, that has been focused on recognition memory, has revealed that two processes contribute to recognition of previously encountered items: recollection and familiarity (Aggleton & Brown, 1999; Eichenbaum, 2006; Eichenbaum, Yonelinas, & Ranganath, 2007; Rugg & Yonelinas, 2003; Skinner & Fernandes, 2007; Squire, Stark, & Clark, 2004; Wixted, 2007a; Yonelinas, 2001a; Yonelinas, 2002). The findings of neural correlates of recollection and familiarity lead to the assumption that there are different brain regions activated in either process, but there are, to the best of my knowledge, no studies assessing how these brain regions are working together in a recollection or a familiarity network, respectively. Additionally, there are almost no studies to date, which directly searched for overlapping regions. Therefore, in study I of the current thesis, brain regions associated to both recognition processes are searched investigated. Additionally, a connectivity analysis will search for functional correlated brain activations that either build a recollection or a familiarity network. It is undoubtable that the Brain Derived Neurotrophic Factor (BDNF) is strongly involved in synaptic plasticity in the hippocampus (Bramham & Messaoudi, 2005) and there is evidence that a genetic variant of this neurotrophin (BDNF 66Met) is related to poorer memory performance (Egan, et al., 2003). Therefore, in study II of the current thesis, the effect of BDNF Val66Met on recollection and familiarity performance and related brain activations is investigated. Finally, one could summarize, that serotonin, like BDNF, is strongly involved in brain development and plasticity as well as in learning and memory processes (Vizi, 2008). More precisely, there is evidence for alterations in the structure of brain regions, which are known to be involved in emotional memory formation and retrieval, like amygdala and hippocampus (Frodl, et al., 2008; Munafo, Brown, & Hariri, 2008; Pezawas, et al., 2005). One study found an slight epistatic effect of BDNF and 5-HTTLPR on the grey matter volume of the amygdala (Pezawas, et al., 2008). Therefore, in study III, it is investigated if such an interaction effect could be substantiated for the amygdala and additionally revealed for the hippocampus. The results of the current thesis allow further comprehension of recollection, hence episodic memory, and point to a special role of the BDNF in temporal and prefrontal brain regions. Additionally, the finding of an epistatic effect between BDNF and serotonin transporter function point to the need of analyzing interactions between genes and also between genes and environmental factors which reveals more information than the study of main effects alone. In conclusion, analyzing behavioral and neural correlates of episodic memory reveal allowed insights in brain functions that may serve as guideline for future studies in clinical populations with memory deficits, including susceptibility factors such as good or bad environment, as well as promising gene variants that influence episodic memory.
158

Effects of neurotrophic factors on motoneuron survival following axonal injury in developing rats

袁秋菊, Yuan, Qiuju. January 2001 (has links)
published_or_final_version / Anatomy / Master / Master of Philosophy
159

Les signaux extracellulaires modèlent la transmission GABAergique dans l'hippocampe en développement : le cas de la leptine / Extracellular cues shape GABAergic transmission in the developing hippocampus : the case of leptin

Guimond, Damien 02 September 2014 (has links)
La présente thèse est liée à l'étude des indices externes au réseau neuronal et comment ceux-ci impactent le développement du système nerveux central. Spécifiquement, notre objectif était d'explorer l'effet de la leptine, une hormone sécrétée par les adipocytes, sur la plasticité développementale GABAergique. Nous avons utilisé des tranches aigues d'hippocampe de rat nouveau-né pour montrer que la leptine induit une potentialisation de la fréquence de l'activité miniature GABAergique, nécessitant une augmentation postsynaptique de calcium et l'activation de voies de signalisation spécifiques. Nous avons confirmé cet effet sur des cultures de neurones hippocampiques, sur lesquelles nous avons commencé à développer une méthode pour mesurer le corrélat morphologique de la plasticité fonctionnelle des synapses GABAergiques en culture. Cette approche suggère que la plasticité GABAergique induite par la leptine pourrait survenir à densité constante de récepteurs GABAA membranaires. La leptine induit donc une potentialisation de l'activité GABAergique dans les neurones hippocampiques en développement. Enfin, nous avons trouvé que les neurones pyramidaux de CA3 reçoivent une activité miniature GABAergique réduite chez des souris ob/ob ne produisant pas de leptine, suggérant que la leptine contribue au développement de la circuiterie GABAergique in vivo. Dans l'ensemble, les études que nous présentons apportent un éclairage nouveau sur le développement d'aires cérébrales dites de « haut niveau », dont nous avons observé qu'elles intègrent des signaux dits de « bas niveau », c'est-à-dire en provenance de la périphérie afin de modeler leur développement. / The present dissertation tackles the larger question of how external cues impact the development of the central nervous system. Our specific aim was to explore the effect of leptin, an adipocyte-derived hormone, on GABAergic plasticity in the developing rodent hippocampus. We used acute hippocampal slices of newborn rats to show that leptin induces a long lasting potentiation of the frequency of miniature GABAergic activity. Using pharmacological tools we found that this event requires a postsynaptic increase in intracellular calcium as well as specific postsynaptic signaling pathways. To address the mechanistic action of leptin we confirmed the leptin-induced plasticity on hippocampal cultures and began to develop a method to measure the morphological correlate of GABAergic synapses in culture. Applying this method suggested that the leptin-induced GABAergic plasticity might occur with a constant density of postsynaptic GABAA receptor puncta. Taken together, these data show that leptin induces a potentiation of GABAergic activity in developing hippocampal neurons, perhaps by recruiting clusters of GABAA receptors expressed at the membrane to form newly functional GABAergic synapses. In addition we found that CA3 pyramidal neurons of leptin-deficient ob/ob mice exhibit lower miniature GABAergic activity compared to wild type littermates, which suggests that leptin contributes to the development of the hippocampal GABAergic circuitry in vivo. Overall, these studies shed a new light on the development of admittedly "higher-level" cerebral regions which were found here to integrate "lower-level", peripheral signals to shape their development.
160

Estudo do polimorfismo Val66Met na população brasileira e influência nos níveis plasmáticos de BDNF e reabilitação de pacientes pós-AVC / Study of Val66Met polymorphism on Brazilian population and the influence on plasmatic levels of BDNF and rehabilitation of post stroke patients

Fontes, Daiane de Oliveira 29 November 2016 (has links)
O número de pessoas acometidas por doenças cérebro vasculares, entre as quais, o acidente vascular cerebral (AVC), constitui um cenário alarmante nos dias atuais, fato que pode estar associado ao aumento da longevidade. A recuperação funcional de pessoas com sequelas de AVC requer a aplicação de técnicas de reabilitação que se baseiam em princípios de neuroplasticidade; no entanto, pouco se sabe quais são os benefícios morfofuncionais resultantes de diferentes abordagens terapêuticas. O presente estudo, portanto, teve como objetivos analisar a concentração plasmática de BDNF antes e após tratamento de reabilitação de indivíduos com AVC e correlacionar com o polimorfismo Val66Met; identificar e comparar a frequência do polimorfismo Val66Met na população brasileira e em pessoas que sofreram AVC. Os procedimentos experimentais foram aprovados pelo Comitê de Ética em Pesquisa da EACH/USP. O estudo foi dividido em duas abordagens experimentais: (i) caracterização genotípica de pessoas com diagnóstico de AVC e sua relação com diferentes protocolos de reabilitação e com o BDNF plasmático e (ii) estudo genético populacional para caracterização da frequência do polimorfismo Val66Met na população brasileira. Participaram deste estudo indivíduos saudáveis dos estados de Alagoas, Rio Grande do Sul e São Paulo (n=1558) e pacientes com sequelas de AVC (n=54). A análise do BDNF plasmático foi realizada por meio do teste imunoenzimático de ELISA e somente os indivíduos submetidos à terapia robótica tiveram níveis aumentados de BDNF circulante. As análises do polimorfismo Val66Met foram realizadas utilizando a técnica de PCR-RFLP (HRM). Não houve associação entre o polimorfismo e os níveis plasmáticos de BDNF. As frequências genotípicas e alélicas do polimorfismo Val66Met dos indivíduos saudáveis e com AVC foram muito semelhantes. Os dados de gênero apontou aumento nos níveis de BDNF em mulheres, entretanto, a idade não interferiu nos níveis de BDNF. Considerando-se os resultados, podemos concluir que o polimorfismo não apresenta relação com a ocorrência de AVC e não interfere nos níveis plasmáticos de BDNF plasmático. No que concerne às técnicas de reabilitação, a terapia robótica pode ser mais efetiva para desencadear eventos de neuroplasticidade considerando o aumento de BDNF circulante após o tratamento. Através do estudo populacional foi possível verificar que o perfil da miscigenação mudou ao longo de três gerações analisadas e confirmamos a presença rara do polimorfismo em pessoas de cor/raça preta e indígena / The number of people affected by cerebrovascular diseases, including the stroke, is an alarming scenario nowadays, which may be associated with the increment of the longevity. Functional recovery of people with stroke sequelae requires the application of rehabilitation techniques based on principles of neuroplasticity, however, the knowledge about how the morphological and functional benefits of different therapeutic approaches is insipient. This study, therefore, aimed to analyze the plasma concentration of BDNF before and after rehabilitation program of patients with stroke and correlate with Val66Met polymorphism; to identify and to compare the frequency of Val66Met polymorphism in the Brazilian population and in the patients who have suffered strokes. The experimental procedures were approved by the Research Ethics Committee of EACH/USP. The study was divided into two experimental approaches: (i) genotypic characterization of people diagnosed with stroke and their relation to different rehabilitation protocols and plasma BDNF and (ii) populational genetic study to characterize the frequency of Val66Met polymorphism in the Brazilian population. The study included healthy individuals in the states of Alagoas, Rio Grande do Sul and São Paulo (n = 1558) and patients with stroke sequelae (n = 54). The analysis of plasma BDNF was performed by immunoenzymatic test ELISA, and only those individuals undergoing robotic therapy had increased levels of circulating BDNF. The analysis of the polymorphism Val66Met was performed using PCR-RFLP (HRM). There was no association between the polymorphism and the plasma levels of BDNF. The genotypic and allelic frequencies of the Val66Met polymorphism of healthy individuals and stroke were similar. The gender data showed an increase in BDNF levels in women, but age did not interfere with BDNF levels. Considering the results, we can conclude that the polymorphism is not related to the occurrence of stroke and does not affect the plasma levels of serum BDNF. As regards the rehabilitation techniques, robotic therapy may be more effective to trigger neuroplasticity events considering the increase of circulating BDNF after treatment. Through the study population was possible to verify that the profile of miscegenation has changed over the three generations examined and confirmed the presence of the rare polymorphism in black and indigenous people

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