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Blood flow change in human masseter muscle elicited by voluntary isometric contractionMonteiro, André Antonio. January 1990 (has links)
Thesis (doctoral)--Karolinska Institutet, Stockholm, 1990. / Extra t.p. with thesis statement and errata sheet inserted. Includes bibliographical references.
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Calcium channel activity and force regulation in smooth muscle effects of polyamines and growth stimulation /Gomez, Maria. January 1998 (has links)
Thesis (doctoral)--Lund University, 1998. / Added t.p. with thesis statement inserted. Includes bibliographical references.
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Efeito das sessões de familiarização sobre o pico de torque e taxa de desenvolvimento de torque = comparações entre jovens, meia idade e idosos = Effect of familiarization sessions on peak torque and rate of torque development : comparisons among young, middle age and elderly / Effect of familiarization sessions on peak torque and rate of torque development : comparisons among young, middle age and elderlyFazolin, Marcio Aparecido Franco de Godoy, 1981- 04 September 2013 (has links)
Orientador: Cláudia Regina Cavaglieri / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Educação Física / Made available in DSpace on 2018-08-22T16:14:08Z (GMT). No. of bitstreams: 1
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Previous issue date: 2013 / Resumo: A contração muscular isocinética, assim como a isométrica balística, tem sido utilizada para determinar o pico de torque (PT) e a taxa de desenvolvimento de torque (TDT), consideradas importantes variáveis neuromusculares. Sessões de familiarização são necessárias para a verificar a estabilidade das medidas em diferentes protocolos de verificar a estabilidade destas medidas. No entanto, ainda não estão claro quantas sessões de familiarização são necessários para estabilizar tais componentes em diferentes idades. O objetivo deste estudo foi determinar o número de sessões de familiarização necessárias para alcançar a estabilidade da medida no PT e TDT a partir da contração isométrica balística e o PT a partir da contração isocinética nas velocidades 60º/s, 180º/s, 240º/s e 300º/s, nas faixas etárias. Sessenta e quatro sujeitos saudáveis participaram de dois protocolos de familiarização: o isométrico balístico, com 31 sujeitos dividos em jovem (idade de 22,75 ± 4,53 anos), meia-idade (idade de 50,45 ± 6,12 anos) e idosos (idade de 67,80 ± 7,28 anos); e o protocolo isocinético com 33 sujeitos dividos em jovens (idade de 21,92 ± 2,57), meia idade (idade de 47,20 ± 5,18 anos) e idosos (idade de 62,08 ± 3,53 anos). Foram realizadas quatro sessões de testes no dinamômetro isocinético separadas por 72h. De acordo com ANOVA, não foram observadas diferenças estatisticamente significantes entre os grupos e entre as sessões respectivamente (jovens, P = 0,92, P = 0,74; meia idade, P = 0,98, P = 0,99; idoso, P = 0,99, P = 0,69) para o protocolo isométrico balístico. Por outro lado, o protocolo isocinético apresentou uma variabilidade nas sessões de familiarização em relação às velocidades angulares analisadas (60º/s e 240ºs, jovem, P = 0,007 e P = 0,02 e meia idade, P = 0,01 e P = 0,007 e grupo idoso 240º/s e 300ºs, P = 0,02 e P = 0,05). Em conclusão, é possível que o nível de atividade física dos sujeitos e o tipo de protocolo utilizado tenham influenciado nas respostas do presente estudo. Os efeitos emanados do processo de envelhecimento parecem influenciar de forma mais acentuada as respostas do PT em contrações isocinéticas / Abstract: The muscular isokinetic contraction, as well as ballistic isometric, has been used to determine the peak torque (PT) and the rate of torque development (RTD), considered important neuromuscular variables. Familiarization sessions are necessary to verify the stability of neuromuscular measures in different protocols. However, it is unclear yet how many familiarization sessions are needed to stabilize these components at different ages. The aim of this study was to determine the number of familiarization sessions required to reach the stability of measure in the PT and RTD from the ballistic isometric contraction and in the PT from the isokinetic contraction at speeds 60°/s, 180º/s, 240º/s and 300º/s in different groups. Sixty-four healthy subjects participated in two familiarization protocols: the ballistic isometric , with 31 subjects divided in, young (age 22.75 ± 4.53 years), middle-age (age 50.45 ± 6.12 years) and elderly (age 67.80 ± 7.28 years): and isokinetic protocol with 33 subjects divided in young (age 21.92 ± 2.57 years), middle age (age 47.20 ± 5.18 years) and elderly (age 62.08 ± 3.53 years). There were four test sessions in isokinetic dynamometer with 72h apart. According to ANOVA, there were no statistically significant differences among groups and among sessions respectively (young P = 0.92, P = 0.74; middle age, P = 0.98, P = 0.99; elderly, P = 0.99, P = 0.69) for the ballistic isometric protocol In the other hand, the isokinetic protocol showed variability in familiarization sessions related to angular velocities analyzed. The number of familiarization sessions to reach the stabilization of PT was divergent angular in angular velocities. In conclusion, it is possible that the level of physical activity of the subjects and the type of protocol used have influenced on responses of the present study. The effects arisen from the aging process seem influence more sharply the responses of PT in isokinetic contractions / Mestrado / Atividade Fisica Adaptada / Mestre em Educação Física
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Contribution à l'étude de la potentialisation de post-activation et de ses implications fonctionnelles chez l'hommeBaudry, Stéphane January 2006 (has links)
Doctorat en Sciences de la motricité / info:eu-repo/semantics/nonPublished
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Régulations monoaminergiques AMPc-dépendantes du coeur sain et pathologique / cAMP-dependent monoaminergic regulations of the healthy and failing heartMeschin, Pierre 01 December 2014 (has links)
La fonction cardiaque est finement régulée par des hormones de type monoamines qui constituent des régulateurs cruciaux de l’activité cardiaque (chronotropie et inotropie). Ces hormones dérivées d’acides aminés aromatiques comprenant les catécholamines et la sérotonine maintiennent l’activité du myocarde dans un cadre physiologique tout en lui permettant de s’adapter aux contraintes environnementales. Les récepteurs cellulaires des monoamines sont couplés à des voies de signalisation qui impliquent un nucléotide cyclique, l’AMPc, et modulent la contractilité des cardiomyocytes par l’intermédiaire de multiples phosphorylations des protéines régulatrices du cycle du calcium (canal calcique de type L, RyR2 ou phospholamban) par la protéine kinase A AMPc-dépendante. Lorsque les monoamines voient leurs activités dérégulées en contextes pathologiques tels que l’insuffisance cardiaque (IC) ou un lors d'un traitement antidépresseur, elles conduisent à une hyperstimulation de leurs récepteurs spécifiques. Cette dernière altère alors les voies impliquant l’AMPc et les flux calciques engendrant des évènements ectopiques proarythmogéniques nommés post-dépolarisations. Ces dysfonctions de la contractilité cellulaire et de l'homéostasie calcique peuvent être à l’origine d’arythmies tissulaires et de morts subites cardiaques. Les altérations de l’homéostasie calcique subsistent en dépit des approches thérapeutiques actuelles (!-bloquants, inhibiteurs de l’enzyme de conversion de l’angiotensine) qui vise à freiner le remodelage myocardique post-ischémique et constituent donc une cible active de la recherche cardiovasculaire. Les Rycals, stabilisateurs pharmacologiques du RyR2, représentent une nouvelle approche visant à remédier à ces altérations. Au sein de ces travaux de recherche, nous avons axé nos études sur les deux voies monoaminergiques AMPc cardiaques majeures, les voies adrénergiques et sérotoninergiques. Un premier axe d’étude a consisté en l’évaluation des bénéfices potentiels d’un nouveau Rycal, le S44121, sur la survenue d’arythmies cellulaires et tissulaires en comparaison d’un !-bloquant de référence, le métoprolol, dans un contexte d’IC post-infarctus chez le rat. L’étude n’a cependant pas mise en évidence de bénéfices du S44121 mais a confirmé la cardioprotection exercée par le métoprolol. Un deuxième axe d’étude a évalué l’implication potentielle au niveau cardiaque de la protéine S100A10 dans la modulation de la voie du récepteur à la sérotonine de type 4 (5-HT4R) en conditions physiologiques ou en contexte d’IC. Cette étude originale a mis en avant pour la première fois dans le coeur sain un rôle de la S100A10 dans l’apparition d’une voie 5-HT4R proarythmogène lorsque son expression est induite par une neurotrophine (Brain-derived neurotrophic factor) ou un antidépresseur (imipramine). En revanche, le rôle de la S100A10 dans la modulation de la voie 5-HT4R en contexte d’IC n’a pas été déterminé de façon certaine. / Cardiac function is tightly regulated by hormones such as monoamines which are substantial modulators of cardiac activity (chronotropy and inotropy). These hormones, derived from aromatic amino acids, maintain myocardial activity in a physiological range and allow the cardiac adaptation to environmental conditions. The cellular receptors to monoamines are coupled to signaling pathways involving a cyclic nucleotide, cAMP, and modulate cardiac activity by phosphorylating several key proteins of calcium handling (L-type calcium channel, RyR2 or phospholamban) by the cAMP-dependent protein kinase A. Deregulation of monoamines in pathological conditions such as heart failure (HF) or during antidepressanttreatment leads to a hyperstimulation of their specific receptors. It therefore induces alterations of the cAMP signaling pathway and calcium handling leading to the occurrence of proarrhythmogenic ectopic cellular events known as afterdepolarizations. These dysfunctions in cellular contractility and calcium handling may cause tissue arrhythmias andeven sudden cardiac death. Calcium handling alterations leading to cardiac arrhythmias remain a clinically relevant issue despite the current therapeutical approaches (!-blockers, angiotensin-converting-enzyme inhibitors) which slow the post-ischemic myocardial remodeling and thus represent an active target in the cardiovascular research field. Rycals, RyR2 pharmacological stabilisers, are a new approach to prevent these alterations. In this work, we focused on the two major monoaminergic cAMP-dependent pathways in the heart, the adrenergic and serotoninergic pathways. In the first part of this work, we aimed to evaluate the potential benefits of a new Rycal, S44121, on cellular and tissue arrhythmias occurrence in post-myocardial infarction rat model. These effects were compared to those of the well-known !-blocker, metoprolol. This study failed to show any strong benefit of S44121 but confirmed the cardioprotection associated with the metoprolol use. In a second part of the work presented here, we aimed to evaluate the potential involvement of the S100A10 protein in the modulation of the cardiac serotonin receptor 4 pathway (5-HT4R) in physiological conditions or during HF. This original study unraveled for the first time a new role for S100A10 in the healthy heart by revealing a functional 5-HT4R pathway when S100A10 expression is induced by neurotrophins such as brain-derived neurotrophic factor or by antidepressant drugs such as imipramine. However, we failed to conclude on a direct evidence for a role of S100A10 in the modulation of the 5-HT4R pathway in the failingheart.
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ADF/Cofilin Activation Regulates Actin Polymerization and Tension Development in Canine Tracheal Smooth MuscleZhao, Rong 03 September 2009 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / The contractile activation of airway smooth muscle tissues stimulates actin polymerization and the inhibition of actin polymerization inhibits tension development. Actin depolymerizing factor (ADF) and cofilin are members of a family of actin–binding proteins that mediate the severing of F–actin when activated by dephosphorylation at serine 3. The role of ADF/cofilin activation in the regulation of actin dynamics and tension development during the contractile activation of airway smooth was evaluated in intact canine tracheal smooth muscle tissues. Two–dimensional gel electrophoresis revealed that ADF and cofilin exist in similar proportions in the muscle tissues and that approximately 40% of the total ADF/cofilin in unstimulated tissues is phosphorylated (inactivated). Phospho–ADF/cofilin decreased concurrently with tension development in response to stimulation with acetylcholine (ACh) or potassium depolarization indicating the activation of ADF/cofilin. Expression of an inactive phospho–cofilin mimetic (cofilin S3E), but not WT cofilin in the smooth muscle tissues inhibited endogenous ADF/cofilin dephosphorylation and ACh–induced actin polymerization. Expression of cofilin S3E in the tissues depressed tension development in response to ACh, but it did not affect myosin light chain phosphorylation. The ACh–induced dephosphorylation of ADF/cofilin required the Ca2+–dependent activation of calcineurin (PP2B). Expression of Slingshot (SSH) inactive phosphatase (C393S) decreased force development and cofilin dephosphorylation. Activation of ADF/cofilin was also required for the relaxation of tracheal muscle tissues induced by forskolin and isoproterenol. Cofilin activation in response to forskolin was not Ca2+–dependent and was not inhibited by calcineurin inhibitors, suggesting it was regulated by a different mechanism. Cofilin activation is required for actin dynamics and tension development in response to the contractile stimulation of tracheal smooth muscle and is regulated by both contractile and relaxing stimuli. These concepts are critical to understanding the mechanisms of smooth muscle contraction and relaxation, which may provide novel targets for therapeutic intervention in the treatment of abnormal airway responsiveness.
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Extremal rays of smooth projective varietiesOcchetta, Gianluca 12 1900 (has links)
No abstract available
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Redução do torque concêntrico e isométrico de joelho e tornozelo em indivíduos diabéticos não é dependente da presença de polineuropatiaFerreira, Jean de Paula 26 February 2016 (has links)
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Previous issue date: 2016-02-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Contextualization: The Diabetes Mellitus (DM) is an epidemic disease in the world and stay associated with right index of morbidity and mortality and about 90% of cases of DM are type 2 (DM2). DM2 develop by inflammatory mechanisms carrying the insulin resistance and consecutively blond hyperglycemia. Believes that in chronic stages the diabetes causes musculoskeletal dysfunctions can be related to inflammatory and metabolic alterations of the DM2 or with diabetic polyneuropathy. Some
studies identified the musculoskeletal alteration in diabetic subjects. However not is clearly if the
polyneuropathy cause muscle alteration proportionality sensitive alterations. Also weren’t observed studies that analyzed the torque in subjects with DM2, considering others factors that could influence the muscle torque production and also not were observed studies analyzing the torque in diabetic subjects during
different types of contractions (concentric, eccentric and isometric). Objectives: The aim of the present study were analyze the torque at concentric eccentric and isometric muscle contractions in diabetic subject with and without polyneuropathy comparing with a control groups. Methods: The peak torques of flexion and extension were acquired using an isokinetic dynamometer, in sitting position. During concentric and eccentric contractions, the joint speed was set at 60°/s. Five maximal voluntary contractions were acquired for concentric and eccentric and 2 for isometric, with a rest
interval of 1.5 minutes. The sequence of the tests was randomized and verbal and visual feedback were standardized and delivered to all subjects by the same person. Three groups of adult males were selected for this study (1) Control group (healthy non-diabetic patients, n=33), (2) Diabetic group (patients with
diabetes mellitus without polyneuropathy, n=31), (3) Neuropathic group (patients with diabetic polyneuropathy, n=28). The Neuropathic group was defined according to a fuzzy model of signs and symptoms. Differences between groups were calculated with one way ANOVA for parametric knee
variables (α of 5%) and Mann Whitney and Willcoxon for non-parametric ankle variables (adjusted α of 1.6%). To describe effect sizes, Hedges’ g was calculated. Results: Irrespective of polyneuropathy, both diabetic groups presented lower peak torques of knee and
ankle, both for isometric contraction and for concentric flexion and extension. Other factors beside the polyneuropathy and early in the diabetes onset, may be influencing in the muscle strength production. The eccentric contraction was not different between any groups. / Contextualização: A Diabetes Mellitus (DM) se tornou uma doença epidêmica em todo mundo, e também está associada a altos índices de morbidade e mortalidade. Cerca de 90% dos casos são de DM do tipo 2, que desenvolve por meio de mecanismos inflamatórios que levam à resistência à insulina e consecutivamente à hiperglicemia sanguínea. Acredita-se que em estágios avançados a DM2 cause disfunções musculoesqueléticas, que podem estar relacionadas às alterações inflamatórias e metabólicas dessa doença ou à polineuropatia diabética (PND). Alguns estudos já identificaram alterações musculoesqueléticas em diabéticos. No entanto, ainda não está claro, se a polineuropatia acomete o sistema
musculoesquelético, na mesma proporção que o sistema sensorial é acometido. Também não se observa na literatura, estudos que tenham analisado o torque de DM2, considerando outros fatores que podem influenciar a produção de torque e estudos que tenham analisado o torque nos três tipos de contrações
(concêntrica, excêntrica e isométrica).
Objetivo: O objetivo do presente estudo foi analisar o torque nas contrações concêntrica, excêntrica e isométrica em indivíduos com DM2, com e sem polineuropatia, comparados a um grupo controle sem DM. Métodos: Foram analisados três grupos de homens adultos (total 92), similares na distribuição de sexo,
idade e características antropométricas: Controles não diabéticos (n=33); DM2 (n=31); PND (n=28). A PND foi avaliada por meio de um modelo Fuzzy. O pico de torque nas contrações concêntrica, excêntrica e
isométrica foi avaliado com um dinamômetro isocinético de cadeira durante a flexão e extensão do joelho e dorsiflexão e flexão plantar do tornozelo. As diferenças entre os grupos foram calculadas com ANOVA
one way, para as variáveis paramétricas de joelho (α of 5%) e Mann Whitney e Willcoxon para dados não paramétricos das variáveis do tornozelo (α ajustado de 1.6%). O tamanho de efeito foi calculado usando Hedges’ g.
Resultados: Independente da polineuropatia, ambos os grupos diabéticos apresentaram menor torque concêntrico e isométrico de joelho e tornozelo, comparados aos Controles, mas sem diferença entre si. Para o torque excêntrico não houve diferença entre os três grupos em todos os movimentos e articulações
avaliadas. Conclusão: A diminuição do torque concêntrico e isométrico em DM2 ocorre mesmo antes da instalação da PND, em tornozelo e joelho, enquanto o torque excêntrico permanece preservado nesses movimentos em diabéticos, independentemente da PND. Observa-se acometimento proximal e distal, com tamanhos de efeito maiores para os movimentos do joelho.
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Étude de l'équilibre entre les voies métaboliques de l'acide arachidonique dans le myomètre de femmes enceintes à termeCorriveau, Stéphanie January 2011 (has links)
Les voies métaboliques de l'acide arachidonique (AA) produisent divers dérivés qui sont impliqués dans le contrôle de la contraction et de la relaxation des muscles lisses.Les métabolites de l'AA sont produits soit par la voie des cyclooxygénases, des lipoxygénases ou celles des cytochromes P450 époxygénase et [oméga]-hydroxylase. À ce jour, aucune étude n'a analysé les effets des eicosanoïdes produits des cytochromes P450 sur le muscle lisse utérin en fin de grossesse. Le but de cette étude est de comparer les effets des différents sous-produits de l'acide arachidonique sur le myomètre gravide humain en situations physiologiques comme dans le cas du travail prématuré. Plus précisément, les objectifs spécifiques étaient de 1) démontrer l'effet des dérivés de l'AA sur l'activité contractile utérine in vitro à partir de tissus utérins de femmes enceintes et 2) d'explorer l'existence d'un équilibre entre les différentes voies métaboliques. Des biopsies utérines ont été réalisées chez des femmes consentantes bénéficiant d'une césarienne élective. Il s'agit d'une étude qui vise à quantifier les effets des eicosanoïdes exogènes sur le myomètre humain en utilisant un modèle in vitro et des mesures de tensions isométriques. Des effets tocolytiques partiels avec environ 40% d'inhibition ont été quantifiés lors de l'ajout des eicosanoïdes suivants: le 8,9-EET, le 14,15-EET et le 20-HETE.Les protéines du myomètre, des membranes foetales et du placenta ont été extraites et analysées par immunobuvardage.Les enzymes de la voie métabolique des EET sont présentes dans les tissus de la sphère utérine. Par la suite, les effets endogènes des EET et du 20-HETE ont été testés de même que ceux des inhibiteurs enzymatiques associés aux différentes voies métaboliques, seuls ou combinés. Par ailleurs, lors de l'utilisation d'inhibiteur, AUDA et DDMS, il a été possible d'observer des effets tocolytiques (20 à 30%) concordant avec un effet produit par les eicosanoïdes endogènes. Dans un second temps, en étudiant la combinaison des inhibiteurs de LOX et de COX favorisant ainsi un éventuel « shunt » métabolique, il a été possible de quantifier un effet tocolytique additif.Les isoformes des lipoxygénases sont présentes dans le tissu de la sphère utérine. Pour conclure, ces résultats innovateurs ont permis de révéler l'importance de la voie des eicosanoïdes dans l'utérus de femmes enceintes à terme.Les enzymes de la voie métabolique de l'acide arachidonique semblent donc être des cibles pharmacologiques intéressantes dans le traitement du travail préterme.
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Time-dependent behaviour of concrete structures with special referenceto podium and frame structuresLiu, Chi-hong., 廖志航. January 2007 (has links)
published_or_final_version / abstract / Civil Engineering / Doctoral / Doctor of Philosophy
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