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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.
1

Material and structural properties of a novel Aer-Tech material

Dan-Jumbo, F. G. January 2015 (has links)
This study critically investigates the material and structural behaviour of Aer-Tech material. Aer- Tech material is composed of 10% by volume of foam mechanically entrapped in a plastic mortar. The research study showed that the density of the material mix controls all other properties such as fresh state properties, mechanical properties, functional properties and acoustic properties. Appreciably, the research had confirmed that Aer-Tech material despite being classified as a light weight material had given high compressive strength of about 33.91N/mm2. The compressive strength characteristics of Aer-Tech material make the material a potential cost effective construction material, comparable to conventional concrete. The material also showed through this study that it is a structural effective material with its singly reinforced beam giving ultimate moment of about 38.7KN. In addition, the Aer-Tech material is seen as a very good ductile material since, the singly reinforced beam in tension showed visible signs of diagonal vertical cracks long before impending rapture. Consequently, the SEM test and the neural network model predictions, carried out had showed how billions of closely tight air cells are evenly distributed within the Aer-Tech void system as well as the close prediction of NN model for compressive strength and density are same with the experimental results of compressive strength and density. The result shows that the Aer-Tech NN-model can simulate inputs data and predicts their corresponding output data.
2

Efeitos do treinamento aer?bio por meio de caminhada na ?gua ou no solo no desempenho f?sico-funcional e na qualidade de vida de mulheres idosas com osteoartrite de joelho.

Arrieiro, Arthur Nascimento January 2011 (has links)
Submitted by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2015-01-21T12:41:53Z No. of bitstreams: 5 dissertacao.pdf: 1514131 bytes, checksum: 9de2bd9e92e5fd7a5a20ccc666cc1e1a (MD5) license_url: 52 bytes, checksum: 3d480ae6c91e310daba2020f8787d6f9 (MD5) license_text: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) license.txt: 2111 bytes, checksum: f5c843397da71f5d32b775fd8c4cbf56 (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2015-01-21T12:51:37Z (GMT) No. of bitstreams: 5 dissertacao.pdf: 1514131 bytes, checksum: 9de2bd9e92e5fd7a5a20ccc666cc1e1a (MD5) license_url: 52 bytes, checksum: 3d480ae6c91e310daba2020f8787d6f9 (MD5) license_text: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) license.txt: 2111 bytes, checksum: f5c843397da71f5d32b775fd8c4cbf56 (MD5) / Made available in DSpace on 2015-01-21T12:51:38Z (GMT). No. of bitstreams: 5 dissertacao.pdf: 1514131 bytes, checksum: 9de2bd9e92e5fd7a5a20ccc666cc1e1a (MD5) license_url: 52 bytes, checksum: 3d480ae6c91e310daba2020f8787d6f9 (MD5) license_text: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) license.txt: 2111 bytes, checksum: f5c843397da71f5d32b775fd8c4cbf56 (MD5) Previous issue date: 2011 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (Capes) / Funda??o de Amparo ? Pesquisa do estado de Minas Gerais (FAPEMIG) / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq) / A caminhada regular ? recomendada como tratamento n?o-farmacol?gico da osteoartrite (OA) de joelho, por?m n?o est?o elucidadas as poss?veis diferen?as entre essa modalidade de exerc?cio quando realizada na ?gua e no solo. Diante disso, o objetivo do estudo foi avaliar os efeitos de um programa de treinamento aer?bio de caminhada na ?gua ou no solo no desempenho f?sico-funcional e na qualidade de vida em idosas com OA de joelho. Para tanto, dezesseis mulheres idosas (idade m?dia: 68 ? 4 anos), com OA do joelho confirmada por exame cl?nico e radiogr?fico, foram divididas aleatoriamente em dois grupos: treino aer?bio com caminhada no solo (N=8) ou na ?gua (N=8). O programa de treinamento teve a dura??o de doze semanas com carga controlada e progressiva (dura??o da sess?o: 30-55 min; intensidade: 72-82% da frequ?ncia card?aca m?xima obtida no teste progressivo). Antes e ap?s o per?odo de treinamento, as volunt?rias foram submetidas a avalia??es do desempenho funcional por meio do teste de caminhada de seis minutos (TC6) e do teste de escada (TE); do desempenho f?sico por meio da an?lise do consumo m?ximo de oxig?nio (VO2max) e do limiar anaer?bio (LA), obtidos atrav?s da realiza??o de um teste progressivo at? a fadiga em uma esteira ergom?trica; do auto-relato de dor, fun??o f?sica e rigidez por meio da aplica??o do Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) e da qualidade de vida utilizando o question?rio Medical Outcomes Study 36-Item Short Form Health Survey (SF-36). Como resultados, a compara??o entre grupos demonstrou que n?o houve diferen?a significativa em nenhuma das vari?veis antes e ap?s o programa de treino. No entanto, a an?lise intragrupo evidenciou melhora significativa no autorrelato de dor e fun??o f?sica, no desempenho do TC6 e TE, no VO2max e VO2max correspondente ao LA e em todos os dom?nios, excetuando aspectos sociais, do question?rio SF-36 em ambos os grupos ap?s o treinamento comparado com antes da interve??o. Concluindo, a realiza??o de um programa de caminhada com carga progressiva e controlada melhora o desempenho f?sico e funcional, bem como a qualidade de vida, independente do meio (?gua ou solo) em idosas com OA de joelho. / Disserta??o (Mestrado) ? Programa Multic?ntrico de P?s-gradua??o em Ci?ncias Fisiol?gicas, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2011.
3

Hybridation des réseaux de neurones : de la conception du réseau à l’interopérabilité des systèmes neuromorphiques

Ambroise, Matthieu 07 December 2015 (has links)
L’hybridation est une technique qui consiste à interconnecter un réseau de neurones biologique et un réseau de neurones artificiel, utilisée dans la recherche en neuroscience et à des fins thérapeutiques. Durant ces trois années de doctorat, ce travail de thèse s’est focalisé sur l’hybridation dans un plan rapproché (communication directe bi-directionnelle entre l’artificiel et le vivant) et dans un plan plus élargies (interopérabilité des systèmes neuromorphiques). Au début des années 2000, cette technique a permis de connecter un système neuromorphique analogique avec le vivant. Ce travail est dans un premier temps, centré autour de la conception d’un réseau de neurones numérique, en vue d’hybridation, dans deux projets multi-disciplinaires en cours dans l’équipe AS2N de l’IMS, présentés dans ce document : HYRENE (ANR 2010-Blan-031601), ayant pour but le développement d’un système hybride de restauration de l’activité motrice dans le cas d’une lésion de la moelle épinière, BRAINBOW (European project FP7-ICT-2011-C), ayant pour objectif l’élaboration de neuro-prothèses innovantes capables de restaurer la communication autour de lésions cérébrales.Possédant une architecture configurable, un réseau de neurones numérique a été réalisé pour ces deux projets. Pour le premier projet, le réseau de neurones artificiel permet d’émuler l’activitéde CPGs (Central Pattern Generator), à l’origine de la locomotion dans le règne animale. Cette activité permet de déclencher une série de stimulations dans la moelle épinière lésée in vitro et de recréer ainsi la locomotion précédemment perdue. Dans le second projet, la topologie du réseau de neurones sera issue de l’analyse et le décryptage des signaux biologiques issues de groupes de neurones cultivés sur des électrodes, ainsi que de modélisations et simulations réalisées par nos partenaires. Le réseau de neurones sera alors capable de réparer le réseau de neurones lésé. Ces travaux de thèse présentent la démarche de conception des deux différents réseaux et des résultats préliminaires obtenus au sein des deux projets. Dans un second temps, ces travaux élargissent l’hybridation à l’interopérabilité des systèmes neuromorphiques. Au travers d’un protocole de communication utilisant Ethernet, il est possible d’interconnecter des réseaux de neurones électroniques, informatiques et biologiques. Dans un futur proche, il permettra d’augmenter la complexité et la taille des réseaux. / HYBRID experiments allow to connect a biological neural network with an artificial one,used in neuroscience research and therapeutic purposes. During these three yearsof PhD, this thesis focused on hybridization in a close-up view (bi-diretionnal direct communication between the artificial and the living) and in a broader view (interoperability ofneuromorphic systems). In the early 2000s, an analog neuromorphic system has been connected to a biological neural network. This work is firstly, about the design of a digital neural network, for hybrid experimentsin two multi-disciplinary projects underway in AS2N team of IMS presented in this document : HYRENE (ANR 2010-Blan-031601), aiming the development of a hybrid system for therestoration of motor activity in the case of a spinal cord lesion,BRAINBOW (European project FP7-ICT-2011-C), aiming the development of innovativeneuro-prostheses that can restore communication around cortical lesions. Having a configurable architecture, a digital neural network was designed for these twoprojects. For the first project, the artificial neural network emulates the activity of CPGs (Central Pattern Generator), causing the locomotion in the animal kingdom. This activity will trigger aseries of stimuli in the injured spinal cord textit in vitro and recreating locomotion previously lost. In the second project, the neural network topology will be determined by the analysis anddecryption of biological signals from groups of neurons grown on electrodes, as well as modeling and simulations performed by our partners. The neural network will be able to repair the injuredneural network. This work show the two different networks design approach and preliminary results obtained in the two projects.Secondly, this work hybridization to extend the interoperability of neuromorphic systems. Through a communication protocol using Ethernet, it is possible to interconnect electronic neuralnetworks, computer and biological. In the near future, it will increase the complexity and size of networks.
4

Uso do cicloerg?metro durante a fase I de reabilita??o da cirurgia de revasculariza??o do mioc?rdio : avalia??o da capacidade funcional

Lopes , Diene Gomes Colvara 11 March 2015 (has links)
Submitted by Setor de Tratamento da Informa??o - BC/PUCRS (tede2@pucrs.br) on 2015-08-04T17:12:26Z No. of bitstreams: 1 473016 - Texto Completo.pdf: 1875230 bytes, checksum: e53279cd3ea9e1ed4b0273503fd159ea (MD5) / Made available in DSpace on 2015-08-04T17:12:26Z (GMT). No. of bitstreams: 1 473016 - Texto Completo.pdf: 1875230 bytes, checksum: e53279cd3ea9e1ed4b0273503fd159ea (MD5) Previous issue date: 2015-03-11 / Objective : To assess the impact of a rehabilitation protocol on the functional capacity of patients who underwent coronary artery bypass graft surgery (CABG), after phase I of rehabilitation, using the cycle ergometer.Method : this is a randomized clinical trial blinded to the evaluator. All patients, older than 50 years old, who underwent CABG and did not meet the exclusion criteria, were invited to participate in the study. After signing the Informed Consent (IC), and being submitted to the surgical procedure, participants were included and randomized to rehabilitation in the control group, with the standard protocol, or in the intervention group, keeping breathing exercises from the standard protocol and replacing the usual physical therapy for 20 minutes of activity in cycle ergometer. Functional assessment was performed at the pre-operative period and on the sixth day after surgery, in order to evaluate balance through the unipodal stance test, mobility through the TUG test and aerobic power assessed by the 6MWT.Results : 19 patients were randomized, being 9 individuals allocated to the intervention group and 10 to the control group. Mean age of the participants in the intervention group was similar to the control group (60.8 ? 4.7 vs 62.4 ? 8.1). There was a predominance of man in both groups (55.6% vs 80.0%). In the intragroup comparisons, individuals from the control group showed a significant decrease in the distance walked in the 6MWT. There was no significant difference between groups considering the other functional variables.Conclusion : Using cycle ergometer in cardiac rehabilitation phase I resulted in similar outcomes considering functional assessment; however, the cycle ergometer allowed better monitoring of hemodynamic and respiratory parameters; therefore, it can be an alternative for rehabilitation of CABG phase I. / Objetivo : Verificar o impacto de um protocolo de reabilita??o sobre a capacidade funcional de indiv?duos submetidos a cirurgia de revasculariza??o do mioc?rdio ap?s a fase I de reabilita??o com o uso do cicloerg?metro.M?todo : Trata-se de um ensaio cl?nico randomizado cegado para o avaliador. Todos pacientes acima de 50 anos que realizaram Cirurgia de Revasculariza??o do Mioc?rdio (CRM) e n?o entravam nos crit?rios de exclus?o eram convidados a participar do estudo, ap?s assinarem o Termo de Consentimento Livre e Esclarecido (TCLE) e ter realizado a cirurgia eram inclu?dos e randomizados para a reabilita??o no grupo controle com protocolo j? utilizado pelo hospital ou no grupo interven??o que mantinha os exerc?cios respirat?rios e substitu?a os exerc?cios de fisioterapia motora habituais por 20 minutos de atividade no cicloerg?metro. A avalia??o funcional utilizados com objetivo de verificar o equil?brio atrav?s do teste de Apoio Unipodal, mobilidade por meio do TUG e capacidade de exerc?cio pelo TC6 foi realizada no pr?-operatorio e no sexto dia de p?s-operat?rio.Resultados : 19 pacientes foram randomizados, sendo 9 alocados no grupo interven??o e 10 no grupo controle. A m?dia de idade do grupo interven??o foi semelhante ? do grupo controle (60,8 ? 4,7 vs 62,4? 8,1) anos. Houve predom?nio do sexo masculino em ambos os grupos (55,6% vs 80,0%). Nas compara??es intragrupo, o grupo controle apresentou uma redu??o significativa na dist?ncia percorrida no TC6,e nas demais vari?veis funcionais avaliadas n?o houve diferen?a significativa entre os grupos.Conclus?o : Uso do cicloerg?metro na fase I de reabilita??o card?aca resultou em efic?cia semelhante para os desfechos funcionais avaliados, sendo que a utiliza??o do cicloerg?metro permitiu um mais adequado monitoramento de par?metros hemodin?micos e respirat?rios, podendo ser mais uma alternativa para a reabilita??o da fase I de CRM.
5

Efeitos agudos e cr??nicos do exerc??cio f??sico sobre as respostas de subst??ncias vasoativas e press??o arterial em indiv??duos com e sem diabetes tipo 2

Sales, Marcelo Pereira Magalh??es de 29 February 2016 (has links)
Submitted by Sara Ribeiro (sara.ribeiro@ucb.br) on 2017-04-18T14:03:26Z No. of bitstreams: 1 MarceloPereiraMagalhaesdeSalesTese2016.pdf: 33116858 bytes, checksum: d66cc0e5bd4a2a18939274bbf98efba8 (MD5) / Approved for entry into archive by Sara Ribeiro (sara.ribeiro@ucb.br) on 2017-04-18T14:04:52Z (GMT) No. of bitstreams: 1 MarceloPereiraMagalhaesdeSalesTese2016.pdf: 33116858 bytes, checksum: d66cc0e5bd4a2a18939274bbf98efba8 (MD5) / Made available in DSpace on 2017-04-18T14:04:52Z (GMT). No. of bitstreams: 1 MarceloPereiraMagalhaesdeSalesTese2016.pdf: 33116858 bytes, checksum: d66cc0e5bd4a2a18939274bbf98efba8 (MD5) Previous issue date: 2016-02-29 / Diabetes is associated with endothelial dysfunction and several cardiovascular disorders, such as systemic arterial hypertension. Moreover, hypertension and diabetes coexist very frequently, as 60-65% of diabetics are hypertensive. The coexistence of hypertension and diabetes can reduce endothelium-mediated vasodilatation, which can be partially explained by a reduced production of nitric oxide (NO) or a decreased response to NO in the vascular smooth muscle. On the other hand, it has been shown that a single session of exercise can promote significant reductions in blood pressure (BP). This occurrence is known as post-exercise hypotension (PEH) and appears to be associated with the activity of the kallikrein-kinin system and release of NO. Although studies have observed PEH in individuais with T2D the molecular mechanisms have not been fully elucidated. ln addition, the prescription of exercise intensities based on lactate threshold (L T) has been suggested for individuais with T2D.Moreover, in spite of previous studies showing that individuais with T2D exhibit PEH when exercising at intensities around LT , There is evidence that subjects with T2D exhibit lower plasma kallikrein activity (PKA) compared to healthy individuais, suggesting that lower NO release and reduced endothelium-dependent vasodilation would be occurring in response to exercise for this population. However, no investigations were made on the integrated responses of PKA, BK, dessArg9-BK and NO and its association to the occurrence of PEH in individuais with or without T2D.Furthermore, to the best of our Knowledge, there is only one study that has investigated the effects of exercise (aerobic and / or resistance) on the 24-hour BP response in individuais with T2D. Not to mention that it is not of our knowledge, studies that have investigated the effects of different aerobic exercise intesities on BP 24 hours in subjects with T2D.Additionally, Several studies have investigated the effects of different exercise modes ( e.g., aerobic vs. resistance ), intensities, and durations on BP responses during the post-exercise recovery period. Studies regarding the effects of different sports modalities, especially martial arts, have also been performed, such as: Tai Chi Chuan, Jiu Jitsu, and Judo. However, until now, no study has explored the BP responses after a single Contact Karate (CK) session. It is worth mentioning that the scientific literature related to combat sports has hardly been explored, especially regarding health-related variables (i.e., post-exercise BP reduction). Most studies have investigated performance-related parameters in athletes, making the evaluation of health-related variables (such as PEH) a scientific gap. Therefore, investigations related to this issue have been strongly encouraged. It should be noted that given the known complications of type 2 diabetes and characteristics of sport (high physical contact of high impact), it is wise to initially investigate the effects of a contact karate session on the blood pressure response after exercise in apparently healthy subjects and then, if possible, in special populations as diabetes and hypertension. With regard to chronic exercise, in particular the resistance exercise, the available literature concerning their effects on the response of NO and, in tum, on BP in individuais with T2D, it is still incipient. To the best of our knowledge, there have been only two randomized clinical trials ofRT's effects on NO concentration and BP levels in T2D patients, only one of which, verified the NO response (along with BP) due to R T. Therefore, there is an apparent lack of evidence on R T' s effects on the responses of NO and BP in T2D patients. Objectives: Study 1) to investigate and compare the responses of PKA, BK, desArg9-BK, NO and BP after a single session of moderate-intensity aerobic exercise in T2D and non-diabetic (ND) individuais; study 2) To verify the effects of different intensities of aerobic exercise on 24-hour ambulatory BP responses in individuais with T2D and prehypertension; study 3) to verify the effects of a Contact Karate (CK) session on BP responses during a post-exercise recovery period in young adults; study 4) to determine the effects of eight weeks RT on the responses of NO and BP in T2D patients and their controls peers. Methods: study l)Ten subjects with T2D and 10 Non-diabetics (ND) underwent three sessions: 1) maximal incremental test on cycle ergometer to determine lactate threshold (L T); 2) 20- min of constant-load exercise on cycle ergometer, at 90% LT and; 3) control session. BP and oxygen uptake were measured at rest and at 15, 30 and 45 min post-exercise. Venous blood samples were collected at 15 and 45 minutes of the recovery period for further analysis of PKA, BK and desArg9-BK. NO was analyzed at 15 minutes post exercise. Study 2) ten individuals with T2D and prehypertension completed three sessions applied in random order: non-exercise control (CON) and exercise at moderate (MOD) and maximal (MAX) intensities. Heart rate (HR), BP, blood lactate concentrations ([Lac ]), oxygen uptake (VO2), and rate of perceived exertion (RPE) were measured at rest, during the experimental sessions, and during the 60 min recovery period. After this period, ambulatory blood pressure was monitored for 24 h. Study 2) ten individuals with T2D and prehypertension completed three sessions applied in random order: non-exercise control (CON) and exercise at moderate (MOD) and maximal (MAX) intensities. Heart rate (HR), BP, blood lactate concentrations ([Lac ]), oxygen uptake (VO2), and rate of perceived exertion (RPE) were measured at rest, during the experimental sessions, and during the 60 min recovery period. After this period, ambulatory blood pressure was monitored for 24 h. Study 3) Thirty-two male CK athletes volunteered and underwent one CK session (50 min) anda control session. BP was measured during rest (before sessions), as well as on the 15th, 30th, 45th, and 60th min of the post-exercise recovery. Study 4) We performed eight-weeks of randomized controlled trial in T2D patients and ND individuals. After initial screening, were randomly allocated into four groups: (1) trained T2D (T2DTRAINED; n = 9), (2) trained ND (NDTRAINED; n = 10), (3) control T2D (T2DCON; n = 8) and (4) control ND (NDCON; n = 7). NO and BP were determined before and after the intervention. Results: study 1) The ND group presented PEH of systolic blood pressure (SBP) and mean arterial pressure (MAP) on the 90% L T session but T2D group did not. Plasma NO increased ~24.4% for ND and ~13.8% for T2D group 15min after the exercise session. Additionally, only ND individuais showed increases in PKA and BK in response to exercise and only T2D group showed increased desArg9-BK production. Study 2) Compared with CON, only MAX elicited post-exercise BP reduction that lasted for 8 h after exercise and during sleep. Study 3) The SBP, diastolic blood pressure, and MAP were significantly lower at the post-exercise period compared to pre-exercise rest (p<.05), with the largest reductions being observed at the 60th min of recovery and at the sarne periods of post-exercise recovery of the control session. Study 4) After eight weeks of RT (three times per week), the T2D and ND experimental groups decreased systolic blood pressure (SBP) by 7.0 and 3.4 mmHg, respectively. However, the control groups showed maintenance (0.24 mmHg for T2D) or elevation (2.2 mmHg for ND) of systolic blood pressure. Although none of these changes were significant (p > .05). As regards the absolute values of BP, T2D subjects who did not undergo the training (T2DCON) tended (p = .057) to have increase SBP and significantly (p = .05) increased MAP. Conclusions: studyl) it was concluded that T2D individuals presented lower PKA, BK and NOx release as well as higher desArg9-BK production and reduced PEH in relation to ND participants after a single exercise session. Study 2) A single session of aerobic exercise resulted in 24 h BP reductions in individuals with T2D, especially while sleeping, and this reduction seems to be dependent on the intensity of the exercise performed. Study 3) a single CK session can promote a decrease in BP for at least 60 min after performing this type of exercise in young adults. Study 4) eight weeks of RT does not increase NO concentrations and, in tum, does not reduce BP in T2D patients-though it prevented its increase. / Introdu????o: o diabetes est?? associado com disfun????o endotelial, bem como com diversas desordens cardiovasculares, como hipertens??o arterial sist??mica (HAS). A HAS e o diabetes coexistem muito frequentemente. Aproximadamente, 60-65% dos diab??ticos s??o hipertensos. A coexist??ncia do diabetes e HAS pode reduzir a vasodilata????o endot??lio-dependente, que pode ser parcialmente explicada por uma reduzida produ????o ou resposta ao ??xido n??trico (ON) na nusculatura vascular lisa. Por outro lado, estudos t??m demonstrado que uma ??nica sess??o de exerc??cio pode promover redu????es significativas na press??o arterial (PA). Esta ocorr??ncia ?? conhecida como hipotens??o p??s-exerc??cio (HPE) e parece estar associada com a atividade do sistema calicre??na-cinina e libera????o do ON. Embora estudos tenham observado HPE em indiv??duos com diabetes tipo 2 (DT2), os mecanismos moleculares relacionados ?? sua ocorr??ncia n??o foram completamente elucidados. Adicionalmente, a prescri????o de intensidades de exerc??cio baseada em cargas relativas ao limiar de lactato (LL) t??m sido sugerida para indiv??duos com DT2. No entanto, apesar de estudos anteriores demonstrarem que os indiv??duos com DT2 apresentam HPE quando submetidos a exerc??cios em intensidades em torno LL . Existe evid??ncia que indiv??duos com DT2 apresentam menor atividade da calicre??na plasm??tica (ACP) em compara????o aos indiv??duos n??o diab??ticos, sugerindo uma menor libera????o de ON e redu????o da vasodilata????o endot??lio-dependente em resposta ao exerc??cio para essa popula????o. Contudo, para o nosso melhor conhecimento, ainda n??o foram realizadas investiga????es sobre as respostas integradas de ACP, bradicinina (BK), des-Arg9-bradicinina, ON e sua associa????o com a ocorr??ncia de HPE em indiv??duos com ou sem DT2. Ademais, salvo melhor ju??zo, existe apenas um estudo que tenha investigado os efeitos do exerc??cio f??sico (aer??bio e/ou resistido) sobre a resposta da PA de 24 horas em indiv??duos com DT2. Sem mencionar que tamb??m n??o ?? do nosso conhecimento, estudos que tenham investigado os efeitos de diferentes intensidades de exerc??cio aer??bio sobre a PA de 24 horas em indiv??duos com DT2. Somando a isso, diversos estudos t??m investigado os efeitos de diferentes modos de exerc??cio (aer??bio vs. resistido), intensidades, e dura????es, sobre as respostas da P A p??s-exerc??cio. Estudos sobre os efeitos de diferentes modalidades esportivas, especialmente artes marciais, tamb??m foram realizados, tais como: Tai Chi Chuan, Jiu Jitsu e Jud??. Contudo, at?? o presente momento, nenhum estudo investigou a resposta da P A ap??s uma ??nica sess??o de Carat?? de contato (CC). Vale ressaltar que a literatura cient??fica relacionada a esportes de combate t??m sido pouco explorada, especialmente em rela????o ??s vari??veis relacionadas com a sa??de ( ou seja, a redu????o da PA p??s-exerc??cio). A maioria dos estudos investigaram os par??metros relacionados com o desempenho em atletas, tornando a avalia????o de vari??veis relacionadas com a sa??de, uma evidente lacuna cient??fica. Portanto, investiga????es relacionadas a este assunto t??m sido fortemente encorajada. Cabe salientar que, dado as conhecidas complica????es do DT2 e as caracter??sticas da modalidade em quest??o ( elevado contato f??sico de alto impacto), torna-se prudente inicialmente investigar os efeitos de uma sess??o de CC sobre a resposta da P A p??s-exerc??cio em indiv??duos aparentemente saud??veis e posteriormente, se poss??vel, em popula????es especiais como diab??ticos e hipertensos. No que se refere ao exerc??cio cr??nico, em particular sobre o exerc??cio de for??a, a literatura dispon??vel a respeito dos seus efeitos sobre a resposta do ON e, por sua vez, sobre a PA em indiv??duos com DT2, ainda ?? muito incipiente. Para o melhor do nosso conhecimento, existem apenas dois ensaios cl??nicos randomizados sobre os efeitos do treinamento resistido (TR) sobre a resposta do ON e P A em pacientes com DT2, dos quais apenas um, verificou a resposta do ON juntamente com a P A frente ao TR. Portanto, h?? uma aparente falta de evid??ncias a respeito dos efeitos do TR sobre as respostas do NO e PA em pacientes com DT2. Objetivos: estudo 1) investigar e comparas as respostas de ACP, BK, desArg9-bradicinina, ON e PA ap??s uma ??nica sess??o de exerc??cio aer??bio realizada em intensidade moderada (90% da carga de LL) em indiv??duos com e sem DT2; estudo 2) verificar e comparar os efeitos de uma ??nica sess??o de exerc??cio aer??bio sobre a resposta da PA de 24 horas e verificar os efeitos da intensidade do exerc??cio aer??bio sobre a resposta da PA 24 h em indiv??duos com DT2 e pr??-hipertensos; estudo 3) avaliar os efeitos de uma ??nica sess??o de CC sobre a resposta da PA p??s-exerc??cio em adultos jovens; estudo 4) investigar os efeitos de oito semanas de TR sobre as respostas de ON e P A em pacientes com DT2 e seus pares controles. M??todos: estudo 1) Dez indiv??duos com e DT2 e 10 n??o diab??ticos (ND) foram submetidos a tr??s sess??es: 1) teste incremental m??ximo em bicicleta ergom??trica para determinar o limiar de lactato (LL); 2) 20 min de exerc??cio de carga constante em cicloerg??metro, em 90% L T e; 3) sess??o controle. PA e consumo de oxig??nio foram mensurados em repouso e aos 15, 30 e 45 min p??s-exerc??cio. Amostras de sangue venoso foram coletadas em 15 e 45 minutos do per??odo de recupera????o para posterior an??lise de ACP, BK e desArg9- bradicinina. ON foi analisado aos 15 minutos ap??s o exerc??cio. Estudo 2) Dez indiv??duos com diabetes tipo 2 e pr??-hipertens??o foram submetidos a tr??s sess??es aplicadas em ordem rand??mica: 1) controle ( CON), sem exerc??cio e exerc??cio em intensidades moderadas (MOD) e m??xima (MAX). A frequ??ncia card??aca (FC), P A, as concentra????es de lactato sangu??neo ([Lac ]), consumo de oxig??nio (V02) e taxa de percep????o de esfor??o (TPE) foram coletados em repouso, durante as sess??es experimentais e durante o per??odo de recupera????o de 60 min. Ap??s esse per??odo, a P A de 24 h foi monitorada. Estudo 3) Trinta e dois atletas CC foram submetidos a uma sess??o de CC (50 min) e uma sess??o CON. A PA foi medida durante o repouso, bem como aos 15, 30, 45 e 60 min da recupera????o p??s-exerc??cio. Estudo 4) Foi realizada oito semanas de estudo randomizado controlado em pacientes DT2 e ND). Ap??s a triagem inicial, foram distribu??dos aleatoriamente em quatro grupos: (1) treinados com DT2 (TREINADODT2; n = 9), (2) treinados ND (TREINADOND; = n 1 O), ( 3) controle DT2 (CON DT2; n = 8) e (4) controle ND (CONND; n = 7). NO e BP foram determinadas antes e ap??s a interven????o. Resultados: estudo 1) somente o grupo n??o diab??tico (ND) apresentou HPE para press??o arterial sist??lica e press??o arterial m??dia na sess??o LT 90%. O ON plasm??tico aumentou ~ 24,4% no grupo ND e ~ 13,8% para o DT2 15 min ap??s a sess??o de exerc??cios. Al??m disso, apenas os indiv??duos ND mostraram aumentos de ACP e BK em resposta ao exerc??cio e somente os DT2 mostraram um aumento da produ????o desArg9-bradicinina. estudo 2) Ademais, comparado com a sess??o CON, somente a sess??o de exerc??cio MAX apresentou HPE, que durou at?? 8 h ap??s o exerc??cio e durante o sono. estudo 3) Em rela????o ao CC, a press??o arterial sist??lica (PAS), diast??lica (PAD) e press??o arterial m??dia (MAP) foi significativamente menor no per??odo p??s-exerc??cio em rela????o ao pr??-exerc??cio repouso, bem como em rela????o a sess??o CON, com as maiores redu????es sendo observadas aos 60 min de recupera????o. estudo 4) Ap??s oito semanas de RT, ambos os grupos experimentais (DT2 e ND), apresentaram diminui????o da PAS em 7,0 e 3,4 mmHg, respectivamente. No entanto, os grupos controle (DT2 e ND) demonstrou manuten????o (0,24 mmHg para DT2) ou eleva????o (2,2 mmHg para ND) da PAS. Embora nenhuma das mudan??as foram significativas (p> 0,05). Conclus??es: estudol) concluiu-se que os indiv??duos comDT2 apresentaram menor libera????o ACP, bradicinina e ON, bem como maior produ????o desArg9-bradicinina e reduzida HPE em rela????o aos participantes do grupo ND ap??s uma ??nica sess??o de exerc??cio. Estudo 2) uma ??nica sess??o de exerc??cio aer??bio resultou em redu????o da PA de 24 h em indiv??duos com DT2, especialmente durante o sono, e esta redu????o parece ser dependente da intensidade do exerc??cio realizado. Estudo 3) uma ??nica sess??o CC pode promover uma diminui????o da PA durante pelo menos 60 minutos depois de realizar este tipo de exerc??cio em adultos jovens. Estudo 4) oito semanas de TR n??o aumenta as concentra????es de ON e, por sua vez, n??o reduz a P A em indiv??duos com DT2, por??m parece impedir o seu aumento.
6

Efeito do treinamento concorrente no controle auton?mico card?aco, desempenho cardiorrespirat?rio, for?a muscular e na composi??o corporal de pessoas vivendo com HIV/AIDS

Andrade, Ricardo Dias de 26 February 2016 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-08-29T19:55:03Z No. of bitstreams: 1 RicardoDiasDeAndrade_DISSERT.pdf: 1416010 bytes, checksum: 12bf51d53442ec4aacf466b8f71ba103 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-09-05T21:40:40Z (GMT) No. of bitstreams: 1 RicardoDiasDeAndrade_DISSERT.pdf: 1416010 bytes, checksum: 12bf51d53442ec4aacf466b8f71ba103 (MD5) / Made available in DSpace on 2016-09-05T21:40:40Z (GMT). No. of bitstreams: 1 RicardoDiasDeAndrade_DISSERT.pdf: 1416010 bytes, checksum: 12bf51d53442ec4aacf466b8f71ba103 (MD5) Previous issue date: 2016-02-26 / Introdu??o: O controle da infec??o pelo HIV atrav?s da TARV, acarretou em diversos efeitos adversos as pessoas vivendo com HIV/Aids (PVHA), como as s?ndromes lipodistr?fica e de wasting. O treinamento f?sico tem sido indicado como forma de retard?-los ou ameniz?-los, os estudos com treinamento f?sico para PVHA t?m mostrado efeitos positivos sobre o controle auton?mico card?aco, composi??o corporal, for?a muscular e na capacidade cardiorrespirat?ria. M?todos: Sete PVHA, do sexo masculino, sob uso da TARV, foram submetidas a uma interven??o com treinamento concorrente durante 18 semanas. O treinamento resistido teve caracter?stica de periodiza??o ondulat?ria, e o treinamento aer?bio prescrito em intensidade leve e de forma linear. O controle auton?mico card?aco foi avaliado pela variabilidade da frequ?ncia card?aca atrav?s dos dom?nios da frequ?ncia (HF, LF e a raz?o LF/HF). Foi aplicado o teste de caminhada de seis minutos para a avalia??o da capacidade cardiorrespirat?ria e do desempenho neuromuscular. Para a avalia??o da for?a muscular foi utilizado o m?todo da tonelagem absoluta, calculada a cada microciclo e mesociclo. As vari?veis antropom?tricas foram analisadas por segmento corporal, sendo obtidas a massa gorda total, do tronco e dos membros superiores e inferiores, al?m da massa corporal e IMC.A an?lise estat?stica foi realizada atrav?s do c?lculo do tamanho do efeito (d de Cohen), exceto para a an?lise da tonelagem absoluta, que foi analisada atrav?s do teste ANOVA one-way, com post hoc de scheffe. Resultados: Foram encontrados tamanhos de efeito alto (d>0,80) para a an?lise da variabilidade da frequ?ncia card?aca para as vari?veis LF e HF, mas n?o para a raz?o LF/HF, ap?s 18 semanas. Tamb?m foram encontrados efeitos moderados (d>0,50) ou fracos (d>0,20) para a composi??o corporal e no desempenho cardiorrespirat?rio. Al?m de diferen?as significativas para a for?a muscular a partir do 4? mesociclo. Conclus?o: O treinamento concorrente induziu efeitos positivos no controle auton?mico card?aco, na composi??o corporal, no desempenho cardiorrespirat?rio e na for?a muscular, assim, a prescri??o de treinamentos com varia??es de cargas, como aplicado neste estudo, deve ser indicado como forma de interven??o n?o medicamentosa para PVHA. / The control of HIV infection by HAART, brought a many of adverse effects to people living with HIV/Aids (PLHA), as a lipodystrophy and wasting syndromes. The physical training has been indicated as means to delay or soften then, the studies with physical training to PLHA have been showed positive effects on cardiac autonomic control, body composition, muscular strength and cardiorespiratory fitness. Seven PLHA, male and under HAART use, Underwent a concurrent training protocol during 18 weeks. The resistance training has an ondulatory periodization, and the aerobic training was conducted in low intensity and linear model. The cardiac autonomic control was evaluated by heart rate variability, through frequency domains (LF, HF and LF/HF ratio). Was applied the six minute walking test evaluate the cardiorespiratory fitness and neuromuscular performance. For the muscular strength evaluation was used the absolute tonnage method, calculated for each microcycle and mesocycle. The anthropometric variables were analyzed for each body segment, being get the total fat mass, trunk and the upper and lower limbs, further body mass and BMI. The statistical analyze was conducted by effect size formula (Cohen?s d), except the absolute tonnage, that was analyzed by ANOVA one-way test, with scheffe post hoc. Were found high effect sizes (d<0,80) to analyze the heart rate variability to the LF and HF variables, but not to LF/HF ratio, after 18 weeks. Also were found moderate (d>0,50) and lower (d>0,20) effect size to body composition and cardiorespiratory fitness. Further the significant difference in muscular strength since fourth mesocycle. The concurrent training induced positive effects on cardiac autonomic control, body composition, cardiorespiratory fitness and the muscular strength, so, the training prescription with load variations, as applied in this study, have be indicated as non-medicine intervention to PLHA.
7

Torta de maca?ba como aditivo em silagem de capim-elefante

Silveira, Hugo Vin?cius Lelis 04 August 2017 (has links)
Submitted by Jos? Henrique Henrique (jose.neves@ufvjm.edu.br) on 2018-08-07T17:20:56Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) hugo_vinicius_lelis_silveira.pdf: 433611 bytes, checksum: f5247fb74b25f1503149b9815b9e8d6e (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2018-10-05T19:15:12Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) hugo_vinicius_lelis_silveira.pdf: 433611 bytes, checksum: f5247fb74b25f1503149b9815b9e8d6e (MD5) / Made available in DSpace on 2018-10-05T19:15:12Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) hugo_vinicius_lelis_silveira.pdf: 433611 bytes, checksum: f5247fb74b25f1503149b9815b9e8d6e (MD5) Previous issue date: 2017 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Objetivou-se com este trabalho avaliar os efeitos da adi??o de doses crescentes do subproduto torta de polpa de Acrocomia aculeata (maca?ba) sobre o valor nutritivo, caracter?sticas fermentativas, perdas do processo fermentativo e influ?ncia na estabilidade aer?bica de silagens de capim-elefante (Pennisetum purpureum Schum.). O delineamento experimental foi inteiramente casualizado com 4 repeti??es. Os tratamentos foram constitu?dos pela forrageira capim-elefante aditivada de seis doses de torta de polpa de coco de maca?ba com base na mat?ria natural (0, 6, 12, 18, 24, 30%). A planta forrageira passou por per?odo de 150 dias de amarmazenamento em silos experimentais de polietileno (PVC). Foi determinado o valor nutritivo, as caracter?sticas fementativas, as perdas e a estabilidade aer?bia.Verificou-se efeito linear crescente (P <0,05) das doses de TPCM sobre o teor m?dio de mat?ria seca (MS), extrato et?reo (EE), lignina, carboidratos n?o fibrosos (CNF) e digestibilidade in vitro da mat?ria seca (DIVMS) das silagens de capim-elefante, entretanto, os teores de fibra em detergente neutro (FDN), fibra em detergente neutro corrigida para cinzas e prote?na (FDNcp), fibra em detergente ?cido (FDA) e prote?na bruta (PB) foram reduzidos linearmente (P<0,05) ? medida que se elevou a adi??o de TPCM. A inclus?o de TPCM elevou linearmente (P<0,05) os valores de pH e reduziu os valores de nitrog?nio amoniacal (N-NH3) das silagens. Os valores de produ??o de efluentes na silagem decresceram linearmente (P<0,05) com a inclus?o do aditivo. Os valores de perda por gases apresentaram resposta quadr?tica (P<0,05) ? medida que se elevou a adi??o de TPCM nas silagens. A estabilidade aer?bica foi afetada nas silagens de capim-elefante, mostrando uma eleva??o na estabilidade a medida que se elevava a dose de inclus?o da TPCM. De forma geral a adi??o da TPCM melhora o valor nutritivo e os par?metros fermentativos da silagem de capim-elefante, sendo recomendado a inclus?o de 15 % desse aditivo. / Disserta??o (Mestrado) ? Programa de P?s-Gradua??o em Zootecnia, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2017. / The objective of this work was to evaluate the effects of the addition of doses of Acrocomia aculeata pulp by-product (maca?ba) on nutritive value, fermentative characteristics, losses of fermentation and influence on aerobic stability of Elephant grass silages (Pennisetum Purpureum Schum.). The experimental design was completely randomized with 4 replicates. The treatments were constituted by Elephant grass forage with six leves of maca?ba coconut pulp cake (MCPC) based on natural matter (0, 6, 12, 18, 24, 30%). The silos were storage by 150 days in experimental polyethylene (PVC) silos. The nutritive value, fementative characteristics, losses and aerobic stability were determined. There was an increasing linear effect (P <0.05) of MCPC doses on the mean dry matter (DM), ether extract (EE), non-fibrous carbohydrates (NFC) and in vitro dry matter digestibility (IVDMD) of Elephant grass silages. However, neutral detergent fiber (NDF), neutral detergent fiber corrected for ash and protein (FDNcp) , acid detergent fiber (ADF), and crude protein (CP) were linearly reduced (P <0.05) as the addition of MCPC was increased. The inclusion of MCPC linearly increased (P <0.05) the pH values and reduced the ammoniacal nitrogen (N-NH3) values of the silages. The values of effluent production in the silage decreased linearly (P <0.05) with inclusion of the additive. The gas loss values presented a quadratic response (P <0.05) as the addition of MCPC to the silages increased. Aerobic stability was affected in Elephant grass silages, showing an increase in stability as the inclusion dose of MCPC was increased. In general, the addition of MCPC improves the nutritive value and fermentative parameters of Elephant grass silage. Recommended the inclusion of 15% of this additive.
8

Efeito agudo do exerc?cio f?sico aer?bio com estimula??o cognitiva sobre a mem?ria e concentra??es s?rica do BDNF em idosos / Acute effect of aerobic exercise with cognitive stimulation on memory and serum BDNF concentration in the elderly

Cavalcante Neto, Francisco Holanda 17 June 2016 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-10-27T00:10:05Z No. of bitstreams: 1 FranciscoHolandaCavalcanteNeto_DISSERT.pdf: 2373054 bytes, checksum: dcc0a85397dbb611c25186bc8aee55da (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-12-27T17:50:13Z (GMT) No. of bitstreams: 1 FranciscoHolandaCavalcanteNeto_DISSERT.pdf: 2373054 bytes, checksum: dcc0a85397dbb611c25186bc8aee55da (MD5) / Made available in DSpace on 2016-12-27T17:50:13Z (GMT). No. of bitstreams: 1 FranciscoHolandaCavalcanteNeto_DISSERT.pdf: 2373054 bytes, checksum: dcc0a85397dbb611c25186bc8aee55da (MD5) Previous issue date: 2016-06-17 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / H? evid?ncias de que o exerc?cio f?sico pode diminuir a perda cognitiva e prevenir a dem?ncia em idosos, assim tamb?m como o treino cognitivo ? outra interven??o que vem sendo investigada, representando o aprendizado de novas formas de resolu??o de problemas, no entanto os estudos que investiguem o exerc?cio f?sico aliado ? estimula??o cognitiva, ainda s?o inconclusivos. Objetivo: Analisar o efeito de uma sess?o de exerc?cio f?sico aer?bio com estimula??o cognitiva no desempenho da mem?ria e no aumento do fator neurotr?fico derivado do c?rebro (BDNF) em idosos. Material e M?todos: O presente estudo se caracteriza como quase experimental, com delineamento crossover randomizado. Tivemos como amostra 30 idosos de ambos os sexos (69,3 ? 5,8 anos de idade; 29,7 ? 3,9 kg.cm-?), que foram submetidos a tr?s diferentes sess?es, sendo duas de exerc?cio f?sico (sess?o com exerc?cios autom?tica e sess?o com est?mulos cognitivos) e uma sess?o controle, cada sess?o teve dura??o de 50 minutos. A mem?ria foi avaliada com o teste de lista de palavras, realizou-se tamb?m uma coleta sangu?nea antes e ap?s cada sess?o a fim de avaliar a varia??o da quantidade s?rica do BDNF. Ap?s a coleta foi verificado a normalidade e homogeneidade das vari?ncias. Utilizou-se ANOVA two-way de medidas repetidas para compara??o entre e intrasess?es das concentra??es de BDNF e mem?ria. Adotou-se como n?vel de signific?ncia estat?stica o p < 5%. Resultados: Na mem?ria, as sess?es n?o foram diferentes entre si, no entanto, houve um efeito significativo no tempo, apontando que houve diminui??o significante no desempenho de mem?ria em todas as sess?es. Nos n?veis de concentra??o do BDNF, as sess?es n?o foram diferentes entre si, do mesmo modo, n?o houve signific?ncia na intera??o tempo ? sess?o. Conclus?o: Uma ?nica sess?o de exerc?cio aer?bio conjugada a estimula??o cognitiva com intensidade moderada n?o ? suficiente para aumentar o fator neurotr?fico derivado do c?rebro, podendo prejudicar o desempenho da mem?ria em tarefas realizadas logo ap?s o exerc?cio. / Human aging is characterized by different physiological and functional changes that may be influenced by lifestyle, genetic and environmental factors. Among the consequences of these changes are cognitive deficits, principally memory, affecting the activities of daily life of elderly. Cognitive training intervention combined with exercise has been widely indicated as an alternative to promote cognitive health, however, studies investigating exercise combined with cognitive stimulation are still rare and inconclusive. Objective: To determine the effects of the combination of single session aerobic exercise with cognitive stimulation over memory performance and increased Brain-Derived Neurotrophic Factor (BDNF) in the elderly. Methods: This study was characterized as almost experimental, with randomized and crossover design, fulfill with 30 elderly men and women (69.3 ? 5.8 years; 29.7 ? 3.9 kg.cm-?) who were subjected to three different sessions, including two sessions of physical exercise (one with automatic exercise and other with cognitive stimulation) and a control session, each session lasted 50 minutes. The memory was evaluated using the word list test, also serum BDNF was measured from blood sampling immediately before and immediately after each session. After the collection, was found normality and homogeneity of variances. We used two-way ANOVA to compare repeated measures both the concentration of BDNF and as the memory test between sessions and the session itself. We adopted as statistically significant level p <5%. Results: In relation to memory, the sessions were not different from each other (F (2, 89) = 0.36, P = 0.697, ?p = 0.008,), however, there was a significant effect in relation to time, indicating that there was a reduction of memory performance in post exercise in all sessions for both the short term memory (control ? p = 0.002, automatic ? p < 0.001 and exercise with stimulation ? p = 0.023) and for work memory (automatic ? p = 0.012 and exercise with stimulation ? p = 0.015). In relation to the levels of concentration of BDNF, the sessions were not different each other (F (2, 90) = 0.06, P = 0.941, ?p = 0.001), in the same way, there was no significance in interaction time ? session (F (2, 90) = 1.37, P = 0.260, ?p = 0.029) and in time (F (1, 90) = 0.14, P = 0.712, = 0.002 ?p). Conclusion: Moderate intensity aerobic exercise simultaneously with cognitive stimulation is not enough to increase the brain-derived neurotrophic factor, which may negatively affect the performance of memory in tasks performed soon after exercise
9

Determining the Role of Wnt5a Signaling in Embryonic Limb Outgrowth via Clonal Analysis

Sowby, Whitney Herrod 14 August 2008 (has links) (PDF)
The exact mechanisms that regulate limb outgrowth the mouse embryo are unknown. Although there are several models, we favor a hypothesis where cells become polarized by signals secreted from the AER which orient their cell migration and/or divisions causing limb outgrowth. Clonal analysis has provided a mechanism to study cell behavior. We have generated a targeting construct containing the Fgf8 inhibitor, Sprouty2, in order to generate mutant clones for behavioral analyses in the limb. In order to more effectively study clonal behavior we report the modification of a novel clonal analysis approach, exo-utero surgery. We have modified, enhanced and proven that this technique can be used successfully in mouse embryos in which we directly apply 4-OHtamoxifen to the limb to induce YFP or β-gal reporter genes in limb mesenchyme. Using this method, we can closely control the timing and location of the induced clones and observe cell behavior during embryonic limb development. Phenotypes of Wnt5a-/- and Ror2-/- exhibit shortened limbs suggesting they function in a similar pathway. Wnt5a and Ror have been found to "colocalize" in the growing limb bud and have also been shown to bind in vitro. Here we show preliminary results about Wnt5a and Ror2 in vivo association by immunoprecipitation of limb bud extracts.
10

Role of Wnt5a and Possible Pathway of Action Through Ror2 in Proximodistal Outgrowth of the Limb

Dahl, Tiffanie M. 11 March 2011 (has links) (PDF)
Despite over 60 years of study, the molecular pathways and mechanisms governing limb outgrowth and patterning remain poorly understood. Fgfs expressed in the AER are known to be necessary and sufficient for proximodistal limb outgrowth and have been proposed to have a chemoattractive role. Wnt5a is a secreted factor which is expressed in a gradient in the distal limb with the highest concentration next to the AER. The presence of the AER is necessary to establish this gradient. Expression of Wnt5a in a concentration dependant manner can be induced in the limb through the implantation of a bead soaked in recombinant Fgf4 protein. This indicates that Fgfs from the AER may establish the gradient of Wnt5a in the limb mesenchyme. Wnt5a-/- mutants exhibit severe shortening of the face, limbs, and body axis, with limbs being progressively truncated proximally to distally. In normal limb proximodistal outgrowth, cells are seen to grow directionally toward the AER. Previous studies done in the Barrow lab, as well as those done by myself, have shown that if a portion of the AER is removed and the cells proximal to this area are labeled, those which are close enough to intact AER will redirect their growth toward this intact AER. When Wnt5a secreting cells are implanted in the limb mesenchyme of the chick this ectopic source of Wnt5a is sufficient to redirect the growth of the mesenchyme cells toward the Wnt5a source. This indicates that the AER may mediate directed growth of limb mesenchyme cells through the establishment of the Wnt5a gradient which provides positional information to the cells. This Wnt5a gradient results in the recruitment of the mesenchyme cells toward the AER. The Ror2 receptor has been found to be involved in several different pathways involving Wnt5a which are involved in changes in polarity and migration. This makes Ror2 a likely candidate for causing changes in cell polarity and migration during distal outgrowth in the limb. To test whether Ror2 is necessary for the polarizing response of limb mesenchyme cells to the Wnt5a gradient in vivo I co-transfected a dominant-negative Ror2 (Ror2ΔC) and a GFP expression vector in the embryonic chick limb using sonoporation. Limb mesenchyme cells transfected with dominant-negative Ror2 grew as radial clones in contrast to the directional outgrowth of the control limb mesenchyme cells along the proximodistal axis. This indicates that cells expressing the dominant-negative Ror2 could no longer respond to the Wnt5a gradient in the limb mesenchyme. This supports a role for Ror2 as a receptor or co-receptor for Wnt5a in mediating directional growth and movement during proximodistal outgrowth and patterning in the limb.

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