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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.
91

Etude de la jonction neuromusculaire dans la sclérose latérale amyotrophique / A study of neuromuscular junction in amyotrophic lateral sclerosis

Bruneteau, Gaëlle 31 March 2014 (has links)
La Sclérose Latérale Amyotrophique (SLA) est une affection neurodégénérative touchant les motoneurones, habituellement mortelle en 3 à 5 ans. La cause de la maladie n'est pas connue et le seul traitement actuellement disponible ne permet qu'un allongement modeste de la survie. Des altérations fonctionnelles de la jonction neuromusculaire (JNM) ont été rapportées dans la SLA mais leur origine physiopathologique n'est pas connue. Nous avons étudié les JNM chez 11 patients atteints de SLA, en associant étude morphologique en microscopie confocale et analyse ultrastructurale. L'analyse fonctionnelle réalisée en EMG de surface retrouvait une anomalie de transmission neuromusculaire (décrément > 10%) chez 45% des patients. Des altérations morphologiques des JNM étaient visibles chez tous les patients, y compris au stade précoce de la maladie. Associé aux anomalies en rapport avec le phénomène de dénervation, nous avons observé un aspect anormal de spiculation de la gouttière primaire dans environ un tiers des cas. Une interposition marquée de la cellule de Schwann terminale entre la terminaison nerveuse et la membrane postsynaptique, pouvant altérer la transmission synaptique, était parfois visible. Nous avons objectivé une réinnervation compensatrice significativement plus importante chez les patients présentant une SLA d'évolution lente et montré que certains facteurs moléculaires musculaires comme l'histone déacétylase 4 pourraient jouer un rôle crucial dans la capacité de réinnervation. Ce travail a mis en évidence des altérations morphologiques majeures au niveau des JNM des patients atteints de SLA et a permis d'identifier des cibles thérapeutiques potentielles. / Amyotrophic Lateral Sclerosis (ALS) is a neurodegenerative disorder affecting motor neurons, usually leading to death in 3 to 5 years. The only treatment currently available, riluzole, has a modest effect on survival. Functional alterations of the neuromuscular junction (NMJ) have been reported in ALS, but their pathophysiological significance remains unknown. We studied the morphology of neuromuscular junctions in muscle samples collected from 11 ALS patients, using confocal and electron microscopy. Functional analysis of the NMJs was performed using surface-recording of compound motor action potentials after repetitive nerve stimulation at slow stimulus rate. A significant decrement (>10%), suggesting impairment of the neuromuscular transmission, was present in 45% of the patients. Morphological alterations of the NMJs were present in all ALS patients even at the early-stages. Beside denervation-induced morphological changes, one third of the NMJs showed abnormal spike-like areas of the outer edge of the postsynaptic primary gutter. A marked interposition of the terminal Schwann cell between the nerve terminal and the postsynaptic membrane, which was likely to alter synaptic transmission, was sometimes present. We found a significantly greater compensatory reinnervation in muscle from patients with slowly progressive ALS. Furthermore, we identified that the muscle molecular factor histone deacetylase 4 could play a key role in muscle reinnervation and disease progression in patients with ALS. This work has highlighted the presence of major morphological changes at the NMJs of ALS patients and identified potential new targets for future treatment.
92

Avaliação histológica e imunoistoquímica da inervação intestinal em cães portadores de intussuscepção submetidos a enterectomia / Histologic and immunohistochemical evaluation of intestinal innervation in dogs with intussusceptions submitted to enterectomy

Barros, Leda Marques de Oliveira 08 September 2008 (has links)
O objetivo do presente trabalho foi avaliar a preservação da inervação de porções intestinais macroscopicamente viáveis em cães portadores de intussuscepções. Para tanto, realizou-se comparação entre segmento intestinal proveniente deste grupo de animais (G1) e segmentos intestinais de animais sem qualquer distúrbio do aparelho digestório (G2). Avaliações histológicas e imunoistoquímicas foram realizadas em sistema computadorizado (Image Pro-Plus®) além da avaliação tardia da qualidade de vida e função digestiva. As variáveis analisadas foram: densidade média das camadas musculares circular e longitudinal, relação entre as camadas musculares, número média de plexos mioentéricos, densidade celular média dos plexos mioentéricos, grau de degeneração neuronal nos plexos mioentéricos, imunoreatividade à sinaptofisina e ao NSE além de existência de distúrbios de defecação. Com exceção da densidade celular média da camada longitudinal, relação entre as camadas musculares e imunoreatividade à sinatpofisina, todos os demais parâmetros apresentaram diferença estatisticamente significativas entre os grupos testados. Foram observadas correlações entre densidade celular média dos plexos mioentéricos e densidade celular média da camada muscular circular; grau de vacuolização dos plexos mioentéricos e imunoreatividade ao NSE; além de grau de vacuolização dos plexos mioentéricos e densidade celular média dos plexos mioentéricos. Quanto aos anticorpos utilizados, o NSE apresentou melhor padrão de marcação quando comparado à sinaptofisina. Dos 13 cães pertencentes ao G1, três foram a óbito no pós-operatório inicial. No período pós-operatório tardio, três cães apresentaram alterações de consistência e freqüência de defecação, além de episódios diarréicos agudos intermitentes. O tempo de segmento foi de 6 meses após intervenção cirúrgica. Os achados deste estudo sugerem que porções intestinais macroscopicamente viáveis podem apresentar lesões de inervação eventualmente traduzidas em sintomatologia clínica futura. Assim sendo, deve-se avaliar de maneira cuidadosa a margem cirúrgica preservada durante o procedimento de enterectomia/enteroanastomose bem como realizar acompanhamento da função digestória tardia. / The purpose of this study was to evaluate the preservation of the innervation of macroscopically viable bowel segments of dogs with intussusceptions. This group (G1) was compared to bowel segment of normal dogs (G2). Histological and immunohistochemical analysis were performed using computed system (Image Pro-Plus®). Late assessment of the quality of life and digestive function were also evaluated. Analyzed variables included: mean density of circular and longitudinal muscular layers cells, ratio between muscular layers, mean of myenteric plexuses, mean density of myenteric cells, neuronal degeneration degree in myenteric plexus, synaptophysin and NSE immunoreactivity and defecatory disorders. All tested parameters, except mean density of longitudinal muscular layers cells, ratio between muscular layers and synaptophysin immunoreactivity, showed statistical differences when group G1 was compared with group G2. Correlations between mean density of myenteric cells and mean density of circular muscular layers cells; neuronal degeneration degree in myenteric plexus and NSE immunoreactivity; neuronal degeneration degree in myenteric plexus and mean density of myenteric cells were observed. Regarding the immunohistochemical antibodies, NSE showed better staining pattern than synaptophysin. Three animals of G1 (n=13) died during the initial post-operative period. During the late post-operative period, three animals presented disorders in fecal consistency, frequency of defecation and acute intermittent diarrheal episodes. The follow-up time was 6 months. These findings showed that macroscopically viable bowel segments can present innervation damage eventually translated in clinical symptoms in the future. So, a careful evaluation of the preserved surgical margin during enterectomy and enteroanastomosis must be carried out as well as monitoring of the late digestive function.
93

Inervação noradrenérgica na ativação da glândula de veneno da serpente Bothrops jararaca. / Noradrenergic innervation in activation of venom gland of Bothrops jararaca snake.

Luna, Milene Schmidt do Amaral e 20 February 2008 (has links)
Neste trabalho, mostramos que a extração de veneno promove aumento na ativação dos fatores de transcrição NF<font face=\"symbol\">kB e AP-1. Noradrenalina, liberada após extração de veneno, é responsável por esse aumento. A estimulação dos adrenoceptores <font face=\"symbol\">a e <font face=\"symbol\">b estão envolvidos nessa resposta, entretanto, o grau de ativação de AP-1 é alterado dependendo do tempo. Foi verificado dimorfismo sexual na ativação dos fatores de transcrição da glândula de veneno, sendo a ativação de NF<font face=\"symbol\">kB mais rápida nas fêmeas do que nos machos e a ativação de AP-1 maior nas fêmeas. Mostramos ainda que a extração de veneno ativa a glândula de veneno através da estimulação da inervação noradrenérgica. Noradrenalina atuando em adrenoceptores <font face=\"symbol\">a e <font face=\"symbol\">b regula a síntese de proteínas da glândula de veneno e não a síntese de toxinas do veneno. Em conclusão, a estimulação da inervação noradrenérgica desencadeia o ciclo de produção de veneno regulando a síntese de proteínas da glândula que provavelmente são essenciais para sua ativação e posterior produção de veneno, através da ativação de fatores de transcrição. Thesis: Noradrenergic Innervation in activation of venom gland of Bothrops jararaca snake. / In this work we showed that venom extraction increases the activation of transcription factors like NF<font face=\"symbol\">kB and AP-1. Noradrenaline released after venom extraction is responsible for NF<font face=\"symbol\">kB and AP-1 activation. Stimulation of both <font face=\"symbol\">a- and <font face=\"symbol\">b-adrenoceptors is involved in this response, however the increase of AP-1 activation is time dependent. A sexual dimorphism has been verified in NF<font face=\"symbol\">kB and AP-1 activation. Activation of NF<font face=\"symbol\">kB occurs earlier in female than in male snakes and activation of AP-1 is greater in female than in male snakes. We also showed that venom extraction activates venom gland by stimulating noradrenergic innervation. Noradrenaline acting at both <font face=\"symbol\">a- and <font face=\"symbol\">b-adrenoceptors regulates synthesis of protein of the venom gland, but not the toxin of the venom. In conclusion, stimulation of noradrenergic innervation triggers the venom production cycle by regulating synthesis of protein that probably is essential to activate venom gland to produce venom by activating transcription factors.
94

Avaliação histológica da distribuição das fibras nervosas periprostáticas em cadáveres humanos com idade superior a 50 anos / Periprostatic nerves distribution in human cadavers aged above 50 years: histologic evaluation

Rodrigues, Tiago Moura 07 December 2016 (has links)
INTRODUÇÃO - O câncer de próstata é a doença maligna mais diagnosticada no mundo, desconsiderando os tumores de pele. A prostatectomia radical tem sido considerada a opção terapêutica preferida no tratamento do câncer clinicamente localizado. O conhecimento da anatomia neurovascular da próstata é de extrema importância para a obtenção de resultados funcionais satisfatórios sem prejuízo aos fins oncológicos. A maioria dos estudos anatômicos já publicados utilizou próstatas removidas cirurgicamente - espécime de prostatectomia radical. Estudos realizados com próstata de cadáveres são importantes por permitir a ressecção em bloco dos órgãos pélvicos, possibilitando uma melhor avaliação da neuroanatomia periprostática. O objetivo deste estudo é avaliar detalhadamente a distribuição das fibras nervosas periprostáticas em cadáveres humanos. MÉTODOS - Foram obtidos 10 blocos viscerais de cadáveres com idade superior a 50 anos constituídos por bexiga, próstata e fáscias adjacentes, uretra proximal e reto. Após fixação em formalina, o bloco visceral foi fatiado transversalmente em fatias de aproximadamente 5 mm. Cada fatia foi dividida em quatro setores, tendo a uretra como eixo central e encaminhada para inclusão em parafina, secção com micrótomo padrão e confecção das lâminas coradas em HE. A cápsula prostática (CP) foi identificada e demarcada e áreas de avaliação foram definidas conforme distância da CP, designadas como distância D1(até 2,5 mm), D2 (2,5 a 5 mm) e D3(maior de 5 mm). Em cada região da próstata (região apical, região média e região basal) as fibras nervosas foram avaliadas de acordo com a distribuição circunferencial nos segmentos anterior, ântero-laterais direito e esquerdo, póstero-laterais direito e esquerdo e posterior e conforme a distância da CP - distâncias D1, D2 e D3. RESULTADOS - Foram identificados 29.275 fibras nervosas, das quais 3.274 (11,18%) foram detectados na região apical, 11.997 (40,98%) na região média e 14.004 (47,84%) na região basal da próstata. Na região basal, aproximadamente, 46% das fibras nervosas foram identificadas nas faces póstero-laterais, 20% na face posterior da próstata e menos de 9% na face anterior. Houve predomínio numérico de FN nas áreas mais distantes, com 46,62% delas sendo identificadas em D3. Na região média, 45% das fibras nervosas se distribuíram nos segmentos anteriores a ântero-laterais. Cerca de 45% se distribuíram igualmente nas faces póstero-laterais direita e esquerda e apenas 10% na face posterior. Nesta região, observou-se que mais de 60% das FN estavam dispostas nas áreas D1. Na região apical, também se observou predomínio de fibras nervosas nos segmentos que compõem as faces posteriores e póstero-laterais (61%). Aproximadamente, 24% das FN se distribuíram igualmente entre as faces ântero-laterais direita e esquerda e quase 15% estavam distribuídas na face anterior do ápice prostático. Mais da metade delas encontravam-se distribuídas a até 2,5 mm da cápsula prostática. Nos segmentos anteriores e ântero-laterais, o predomínio de FN nas áreas D1 foi mais acentuado do que nos outros segmentos. Na avaliação geral, a quantidade relativa de fibras nervosas identificadas nas áreas D1 variou de maneira inversamente proporcional à quantidade relativa de FN das áreas D3. Nas áreas demarcadas entre 2,5 mm e 5 mm da CP (D2), a quantidade relativa de fibras nervosas se manteve relativamente constante. CONCLUSÕES - No sentido craniocaudal, a quantidade de fibras nervosas diminui progressivamente, a distribuição circunferencial se modifica, com aumento da quantidade relativa de fibras nervosas nas faces anteriores e a distribuição em relação à distância da próstata também se modifica, com aumento da quantidade relativa de fibras nervosas nas áreas mais próximas da próstata. A quantidade relativa de fibras nervosas dispostas a uma distância mínima de 2,5 mm da cápsula prostática se mantém constante / INTRODUCTION - Prostate cancer is the most commonly diagnosed malignancy in the world, excluding skin tumors. The incidence of localized tumor increased substantially after the PSA era. Consequently, the percentage of men treated by radical surgery for clinically localized prostate cancer increased. The exact paths of periprostatic nerves have been under debate over the last decades. In the present study, the topographic distribution of nerves around the prostate and their relative distances from the prostatic capsule were analyzed in male cadaver visceral blocs. METHODS - The pelvic organs from ten fresh male cadavers were removed and serial sectioned en bloc for histological investigation. The prostatic capsule was identified, and distances of 2.5 mm and 5 mm from the prostate were demarked with lines. We quantified the number of nerve fibers present in each subsector of each slide and recorded their position relative to the prostatic capsule. RESULTS - A total of 29,275 nerve fibers were identified, of which 3,274 (11.18%) were detected in the apex, 11,997 (40.98%) in the middle and 14,004 (47.83%) in the basal area of the prostate. The majority of nerves were identified in the posterolateral and posterior surfaces of the prostate. At the apical region, the percentage of nerve fibers identified in the anterior region was higher. The nerves identified at the apex were mainly located up to 2.5 mm from the prostate. This proximity to the prostate was specifically observed in the ântero-lateral and anterior sectors. In the craniocaudal sense, the percentage of nerves identified between 2.5 and 5 mm from the prostatic capsule remained constant. CONCLUSIONS - A significant number of nerve fibers were present in the anterior and ântero-lateral positions, especially at the apex. The anterior nerves were closer to the prostate. This proximity suggests that the anterior nerves may participate in local physiology. It is likely that the safe distance of 2.5 mm from all surfaces of the prostate may be related to cavernous fiber preservation
95

Characteristics of enteric neural crest stem cells and their therapeutic potential on hirschsprung's disease. / CUHK electronic theses & dissertations collection

January 2010 (has links)
For the purpose of developing an effective therapeutic strategy for HSCR, the enteric neural crest stem cells were investigated firstly which were isolated from the E14.5 mouse embryonic gut, cultured as neurospheres and characterized by multiple immunofluorescence and reverse transcription-PCR, population doubling time, frequency of forming secondary neurospheres and limited dilution assay. In the differentiation culture medium, several types of cells were induced to form from the neurospheres derived from single cells. Hence the putative enteric neural crest stern cells, which were isolated from the embryonic mouse gut tube and cultured as neurospheres for many passages ex vivo with the demonstrated capacity of proliferation, self-renewal and differentiation, showed properties of stem cells. / Hirschsprung's disease (HSCR) is caused by the absence of the enteric neural crest-derived neurons at the distal region of the gut. Cell-based therapy using stem cells or progenitors gives the potential to supplement these missing enteric neurons in the gut. Enteric neural crest stem cells isolated from the human or rodent gut can give rise to neurons and glia after they are transplanted into the recipient guts of the mouse or rat. However, numbers of issues are unresolved about the basic biology of the enteric nervous system, the characteristics of the stem cells isolated from the enteric nervous system and the biological significance of these cells in prenatal and postnatal periods. In this study, the characteristics and therapeutic potential on HSCR of the enteric neural crest stem cells were explored. / In addition to the above, a recombination organotypic gut culture ex vivo showed that the colonization of enteric neural crest-derived cells in the recipient gut was influenced not only by the genotypes of enteric neural crest-derived cells themselves but also the microenvironment of the gut through which enteric neural crest-derived cells migrated. For instance, the developmental stage of the recipient gut and also the presence of endogenous enteric neural crest-derived cells along the migratory pathway of neural crest-derived cells both affected the extent of the migration and colonization of exogenous enteric neural crest-derived cells and stem cells. The gradual maturation and differentiation of the neighboring structures, such as the smooth muscle layer, during the time period of the enteric neural crest cells migration, might also suggest that these neighboring tissues may have a role in regulating the neural crest-derived cells migration. / In conclusion, enteric neural crest stem cells isolated from the embryonic mouse gut tube showed properties of stem cells, and had the potential to compensate missing enteric neural crest-derived cells both ex vivo and in vivo. However, the colonization of enteric neural crest-derived cells in the developing gut was affected cell-autonomously and also by the microenvironment of the gut and the presence of existing enteric neural crest-derived cells. / Their potential applications in the transplantation experiments were shown by transplantation of the neurospheres isolated to the gut tube maintained in an organotypic culture or to the descending colon of neonates at postnatal day 7. The development of the enteric neural crest stern cells from the neurospheres was found to be compatible to endogenous enteric neural crest-derived cells in the recipient gut as evidenced by the formation of interconnected cellular networks of donor stem cells and endogenous neural crest-derived cells. The enteric neural crest stem cells also possess the potential to compensate the loss of enteric neural crest-derived cells ex vivo and in vivo in recipient prenatal and postnatal guts. / Bao, Lihua. / Adviser: Wood Yee Chan. / Source: Dissertation Abstracts International, Volume: 73-01, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 208-228). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.
96

Origem e distribui??o antim?rica dos nervos do plexo braquial em Macaca mulatta (Zimmermann, 1780) (Cercopithecidae, Primates) / Origin and antimeric distribution of the brachial plexus nerve in Macaca mulatta (Zimmermann, 1780) (Cercopithecidae, Primates).

Sousa, Carlos Augusto dos Santos 03 February 2016 (has links)
Submitted by Leticia Schettini (leticia@ufrrj.br) on 2017-04-24T14:23:01Z No. of bitstreams: 1 2016 - Carlos Augusto dos Santos Sousa.pdf: 2340153 bytes, checksum: 5ef373f242c2c4700a9a9e55280bc62c (MD5) / Made available in DSpace on 2017-04-24T14:23:01Z (GMT). No. of bitstreams: 1 2016 - Carlos Augusto dos Santos Sousa.pdf: 2340153 bytes, checksum: 5ef373f242c2c4700a9a9e55280bc62c (MD5) Previous issue date: 2016-02-03 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Morphology studies provide knowledge that allow us to understand how animals interact with the natural environment or in captivity. In this context, the comparative anatomy of the formation of the brachial plexus awakens interest since the nineteenth century and remains one of the most intriguing topics of contemporary anatomy. The aim of this study was to describe the origin and the antimeric distribution of the brachial plexus nerves in Macaca mulatta, as well as the innervated muscles. Ten male rhesus monkeys (Macaca mulatta) were used, from the Non-human Primates? Breeding Department at the Laboratory Animals Breeding Centre (Cecal/Fiocruz), donated to the Animal Anatomy Department of the Rural Federal University of Rio de Janeiro (UFRRJ). The specimens were fixed in formaldehyde solution by infusion of 10% solution. They were subsequently wrapped in a low-density polythene container with 500 liters of formaldehyde 30% solution over a period of 12 months. After this period, they were washed in running water and subjected to X-ray examinations of the neck at the Small Animals Veterinary Hospital of the UFRRJ to characterize the number of cervical vertebrae. Then, they had both antimeres dissected aiming at the exposure of the origins and the nerves arising from the brachial plexus. Data were presented both in absolute frequency and in simple percentage. In 11 (55%) animals the resulting nerves were constituted by the connections between the ventral spinal branches C5, C6, C7, C8 and T1. In 5 (25%) animals, the participants roots were C4, C5, C6, C7, C8, T1 and T2. In 2 (10%) animals C5, C6, C7, C8, T1 and T2. In the other 2 (10%) animals the formation of the plexus was observed from C6, C7, C8, T1 and T2. The ventral branches formed three nerve trunks: cranial, middle and caudal. The suprascapular nerves, subscapular, axillary, musculocutaneous, radial, median, ulnar innervated the intrinsic muscles and the subclavian nerve innervated the thoracodorsal, medial cutaneous arm and forearm, long thoracic, cranial pectoral and caudal pectoral innervate extrinsic muscles. The results obtained in this study contribute to the comparative anatomy of primates and to the information for applied research, serving as basis for clinical and surgical procedures that uses this species as an animal model. / Estudos morfol?gicos fornecem conhecimentos que permitem entender o modo como os animais interagem com o ambiente natural ou em cativeiro. O objetivo desse estudo foi descrever a origem e a distribui??o antim?rica dos nervos do plexo braquial em Macaca mulatta, assim como dos m?sculos inervados. Foram utilizados 10 cad?veres de Macaca mulatta do sexo masculino, oriundos do Servi?o de Cria??o de Primatas N?o Humanos do Centro de Cria??o de Animais de Laborat?rio (Cecal/Fiocruz) doados a ?rea de Anatomia Animal da Universidade Federal Rural do Rio de Janeiro (UFRRJ). Os esp?cimes foram fixados com perfus?o de solu??o de formalde?do a 10%. Posteriormente, foram acondicionados em caixas de polietileno de baixa densidade com capacidade de 500 litros contendo solu??o de formalde?do a 30% por um per?odo de 12 meses. Ap?s este per?odo, foram lavados em ?gua corrente e submetidos a exames radiogr?ficos da regi?o cervical no Hospital Veterin?rio de Pequenos Animais da UFRRJ para a caracteriza??o do n?mero de v?rtebras cervicais. Em seguida, foram dissecados at? a exposi??o das origens e dos nervos oriundos do plexo braquial. Os dados foram representados em frequ?ncia absoluta e percentual simples. Em 11 (55%) os nervos resultantes foram constitu?dos das conex?es entre os ramos espinhais ventrais de C5, C6, C7, C8 e T1. Em 5 (25%) as ra?zes participantes foram C4, C5, C6, C7, C8, T1 e T2. Em 2 (10%) de C5, C6, C7, C8, T1 e T2. Em outros 2 (10%) verificamos a constitui??o do plexo a partir de C6, C7, C8, T1 e T2. Os ramos ventrais formaram tr?s troncos nervosos: cranial, m?dio e caudal. Os nervos supraescapular, subescapulares, axilar, musculocut?neo, radial, mediano, ulnar inervaram a musculatura intr?nseca e os nervos subcl?vios, toracodorsal, tor?cico longo, peitoral cranial e peitoral caudal inervaram a musculatura extr?nseca. Tamb?m foram registrados os nervos cut?neos oriundos do plexo braquial, sendo eles o nervo cut?neo medial do bra?o, nervo cut?neo medial do antebra?o e ramos para a musculatura cut?nea do tronco. Os dados descritos neste estudo contribuem para a anatomia comparada de primatas e fornecem informa??es para a pesquisa aplicada, servindo como base para procedimentos cl?nico-cir?rgicos em que venha a se utilizar esta esp?cie como modelo experimental.
97

Origins and use of the stochastic and sound-evoked extracellular activity of the auditory nerve

Brown, Daniel January 2007 (has links)
[Truncated abstract] The present study investigated whether any of the characteristics of the compound action potential (CAP) waveform or the spectrum of the neural noise (SNN) recorded from the cochlea, could be used to examine abnormal spike generation in the type I primary afferent neurones, possibly due to pathologies leading to abnormal hearing such as tinnitus or tone decay. It was initially hypothesised that the CAP waveform and SNN contained components produced by the local action currents generated at the peripheral ends of the type I primary afferent neurones, and that changes in these local action currents occurred due to changes in the membrane potential of these neurones. It was further hypothesised that the lateral olivo-cochlear system (LOCS) efferent neurones regulate the membrane potential of the primary afferent dendrites to maintain normal action potential generation, where instability in the membrane potential might lead to abnormal primary afferent firing, and possibly one form of tinnitus. We had hoped that the activity of the LOCS efferent neurones could be observed through secondary changes in the CAP waveform and SNN, resulting from changes in the membrane potential of the primary afferent neurones. The origins of the neural activity generating the CAP waveform and SNN peaks, and the effects of the LOCS on the CAP and SNN were experimentally investigated in guinea pigs using lesions in the auditory system, transient ischemia and asphyxia, focal and systemic temperature changes, and pharmacological manipulations of different regions along the auditory pathway. ... Therefore, the CAP and SNN are altered by changes in the propagation of the action potential along the primary afferent neurones, by changes in the morphology of the tissues surrounding the cochlear nerve, and by changes in the time course of the action currents. If the CAP waveform is not altered, the amplitude of the 1kHz speak in the spontaneous SNN can be used as an objective measure of the spontaneous firing rate of the cochlear neurones. However, because the SNN contains a complex mixture of neural activity from all cochlear neurones, and the amplitude of the spontaneous SNN is variable, it would be difficult to use the spontaneous SNN alone as a differential diagnostic test of cochlear nerve pathologies. To record extratympanic electrocochleography (ET ECochG) from humans, a custom-designed, inexpensive, low-noise, optically isolated biological amplifier was built. Furthermore, a custom-designed extratympanic active electrode and ear canal indifferent electrode were designed, which increased the signal-to-noise ratio of the ECochG recording by a factor of 2, decreasing the overall recording time by 75%. The human and guinea pig CAP waveforms recorded in the present study appeared similar, suggesting that the origins of the human and guinea pig CAP waveforms were the same, and that experimental manipulations of the guinea pig CAP waveform can be used to diagnose the cause of abnormal human ECochG waveforms in cases of cochlear nerve pathologies.
98

Spinal nerve innervation to the sonic muscle and sonic motor nucleus in red piranha, Pygocentrus nattereri (Characiformes, Ostariophysi)

Onuki, Atsushi, Ohmori, Yasushige, Somiya, Hiroaki January 2006 (has links)
journal's webpage is available at http://www.karger.com/bbe .
99

Žmogaus epikardinių nervinių mazgų topografijos ir sandaros ypatumai prenataliniu laikotarpiu / The Peculiarities of Topography and Morphology of the Human Epicardiac Neural Ganglia during Prenatal Period

Saburkina, Inga 29 January 2008 (has links)
Intrakardinė nervų sistema atlieka svarbų vaidmenį reguliuodama širdies ritmą, miokardo laidumą ir susitraukimo jėgą bei vainikinių arterijų tonusą. Neišnešiotų kūdikių intrakardinės inervacijos topografija yra svarbi, atliekant perkateterinę radijodažninę abliaciją, taikomą medikamentiniam gydimui rezistentiškų supraventrikulinių bei atrioventrikulinių reciprokinių tachikardijų atvejais. Tyrėjų duomenys, apie mazgų topografiją bei struktūrinę organizaciją, yra gana skirtingi ir, kad žmogaus vaisių širdies intrakardinis nervinis rezginys iš tiesų nėra pakankamai ištirtas. Todėl darbo tikslas buvo ištirti žmogaus epikardinių nervinių mazgų topografiją ir morfologij�� įvairaus amžiaus vaisių širdyse. Disertacinio darbo rezultatai rodo, kad (1) žmogaus epikardiniai nerviniai mazgai yra lokalizuoti definityvinėse vietose jau penkiolikos savaičių vaisiaus širdyje; (2) epikardinių mazgų skaičius ir pasklidimas žmogaus 15-40 savaičių vaisiuose nėra susijęs su amžiumi; (3) epikardinių nervinių subrezginių mazgų laukų topografija yra pastovi tirtose vaisių širdyse; (4) epikardinių nervinių subrezginių mazgų laukų struktūra – ganglijų skaičius ir jų sritinė lokalizacija yra individualiai kintantys; (5) epikardinių mazgų ir mazginių neuronų dydis, o taip pat mazgų forma bei tarpmazginių nervų skaičius yra susiję su vaisių amžiumi. / Intrinsic cardiac nervous system plays a crucial role in regulation of heart rate, contractility and tone of the coronary vessels. In neonates and infants, the intrinsic neural pathways are considered to be important for radiofrequency ablation that is performed in cases of incessant supraventricular and atrioventricular nodal reentrant tachycardia. Findings regarding to topography of intrinsic cardiac ganglia in the human fetuses differ substantially and deserves a further examination. The aim of this study was to investigate the topography and morphology of the human epicardiac neural ganglia during prenatal period. Results of the present study show, that: (1) the human fetal epicardiac ganglia are in their definitive location already from 15 weeks of gestation; (2) the number of the fetal epicardiac ganglia does not age-dependent and does not differ significantly between the fetal and the adult humans; (3) the distribution of the fetal epicardiac ganglia does not age-dependent; (4) the variability of the neural ganglionated fields, including both the ganglion number and the regional ganglion density, vary substantially from heart to heart; (5) the sizes of epicardiac ganglia in the human fetuses differ substantially from the adult ones, and that the ganglion structure, ganglion size and the number of interganglionic nerves are dependent on gestation stage of the human fetuses.
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Žmogaus plautinių venų nervinio rezginio morfofunkcinės ypatybės / Morpho–functional pecularities of intrinsic neural plexus on the human pulmonary veins

Vaitkevičius, Raimundas 26 January 2010 (has links)
Plautines venas, kaip ir širdies miokardą, kontroliuoja širdies nervinė sistema. Nors žmogaus epikardinis nervinis rezginys šiuo metu yra nemažai tyrinėtas, plautinių venų inervacija į tyrėjų akiratį pateko tik po darbų, įrodančių žmogaus plautinių venų ir kairiojo prieširdžio anatominių struktūrų, tarp jų ir intramuralinių nervinių mazgų ir nervinių kelių, svarbų vaidmenį širdies aritmijų genezėje. Šio tyrimo tikslas buvo vizualizuoti plautinių venų nervines struktūras totaliuose žmogaus kairiojo prieširdžio–plautinių venų preparatuose, parodant žmogaus plautinių venų nervų ir nervinių mazgų ryšį su širdies nervine sistema. Mokslinio tyrimo metu spręsti šie uždaviniai: 1) nustatyti inervacijos kelius, kuriais nervai plinta žmogaus plautinėse venose bei įvertinti sritis, išsiskiriančias nervinių struktūrų gausa, 2) ištirti žmogaus plautinių venų žiočių ir jų sienos sluoksnių nervinius komponentus bei jų pasiskirstymo ypatybes, 3) nustatyti parasimpatinei, simpatinei ir aferentinei nervų sistemai priskiriamų žymenų, atitinkamai cholinacetiltansferazės, tirozinhidroksilazės, su kalcitonino genu susijusio peptido ir substancijos P, lokalizaciją ir pasiskirstymo ypatumus žmogaus plautinėse venose. Šiame darbe atliktuose neuromorfologiniuose tyrimuose buvo panaudotos žmogaus vaisių ir suaugusių žmonių širdys, paimtos autopsijų metu. Plautinių venų nervinis rezginys išryškintas, taikant histocheminį acetilcholinesterazės metodą ir imunohistochemines reakcijas. Remiantis tyrimo... [toliau žr. visą tekstą] / Although the crucial role in a spontaneous atrial fibrillation falls on cardiomyocytes of the human pulmonary veins, the autonomic nervous system is not considered only as the strong regulator of atrial electrophysiology but it is also the major initiator of atrial fibrillation due to a disordered interaction between the atrial autonomic nerves and the cardiomyocytes of the pulmonary vein. The aim of the present study was to investigate the intrinsic neural plexus on whole (non–sectioned) human pulmonary veins. The objectives of the study was: 1) to determine the sources and morphology of nerve routes by which intrinsic nerves supply the human pulmonary veins, 2) to examine the neural structures located within distinct wall layers of the human pulmonary veins, 3) to identify the distribution and expression of tyrosine hydroxylase, choline acetyltransferase, calcitonin gene related peptide and substance P positive nerve structures on the human pulmonary veins as corresponding markers for sympathetic, parasympathetic and sensory nerve cells and fibers. Twenty–two hearts of the human fetuses and thirty five hearts of the adult humans containing the full set of pulmonary veins were investigated applying a histochemical methods for acetylcholinesterase to stain intrinsic neural structures with their subsequent stereomicroscopic examination. ChAT, TH, substantia P and CGRP immunoreactive nerves structures were also studied in the pulmonary veins sections, obtained from the six... [to full text]

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