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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.
71

Autonomic Imbalance - a Precursor to Myopia Development?

Chen, Jennifer C. January 2003 (has links)
While prolonged nearwork is considered to be an environmental risk factor associated with myopia development, an underlying genetic susceptibility to nearwork-induced accommodative adaptation may be one possible mechanism for human myopia development. As the control of accommodation by the autonomic system may be one such genetically predetermined system, this research sought to investigate whether an anomaly of the autonomic control of accommodation may be responsible for myopia development and progression. The emphasis of this work was determining the effect of altering the sympathetic input to the ciliary muscle on accommodation responses such as tonic accommodation and nearwork-induced accommodative adaptation in myopes and non-myopes. The first study of the thesis was based on observations of Gilmartin and Winfield (1995) which suggested that a deficit in the sympathetic inputs to the ciliary muscle may be associated with a propensity for myopia development. The effect of ß-antagonism with timolol application on accommodation characteristics was studied in different refractive error groups. Our results support the previous findings that a deficit of sympathetic facility during nearwork was not a feature of late-onset myopia. However it was found that classifying myopes according to stability of their myopia and their ethnic background was important and this allowed differentiation between accommodation responses and characteristics of the ciliary muscle autonomic inputs, with the greatest difference observed between Caucasian stable myopes and Asian progressing myopes. Progressing myopes, particularly those with an Asian background, demonstrated enhanced susceptibility to nearwork-induced accommodative adaptation and this was suggested to result from a possible parasympathetic dominance and a relative sympathetic deficit to the ciliary muscle. In contrast, stable myopes, particularly those with an Asian background, demonstrated minimal accommodation changes following nearwork (counter-adaptation in some cases), and increased accommodative adaptation with ß-antagonism, suggesting sympathetic dominance as the possible autonomic accommodation control profile. As ethnic background was found to be an important factor, a similar study was also conducted in a group of Hong Kong Chinese children to investigate if enhanced susceptibility to nearwork-induced changes in accommodation may explain in part the high prevalence of myopia in Hong Kong. Despite some minor differences in methodology between the two studies, the Hong Kong stable myopic children demonstrated counter-adaptive changes and greater accommodative adaptation with timolol, findings that were consistent with those of the adult Asian stable myopes. Both Asian progressing myopic children and adults also showed greater accommodative adaptation than the stable myopes and similar response profiles following ß-adrenergic antagonism. Thus a combination of genetically predetermined accommodation profiles that confer high susceptibility and extreme environmental pressures is a likely explanation for the increase in myopia over the past decades in Asian countries. The hypothesis that a sympathetic deficit is linked to myopia was also investigated by comparing the effect of â-stimulation with salbutamol, a ß-agonist, on accommodation with that of ß-antagonism using timolol. It was hypothesized that salbutamol would have the opposite effect of timolol, and that it would have a greater effect on subjects who demonstrated greater accommodative adaptation effects, i.e. the progressing myopes, compared to those who showed minimal changes in accommodation following nearwork. Consistent with the hypothesis, the effect of sympathetic stimulation with salbutamol application was only evident in the progressing myopes whom we hypothesized may have a parasympathetic dominance and a relative sympathetic deficit type of autonomic imbalance while it did not further enhance the rapid accommodative regression profile demonstrated by the stable myopes. Characteristics of the convergence system and the interaction between accommodation and convergence were also investigated in the Hong Kong children. No significant differences in response AC/A ratios between the emmetropic, stable and progressing myopic children were found and it was concluded that elevated AC/A ratios were not associated with higher myopic progression rate in this sample of Hong Kong children. However, ß-adrenergic antagonism with timolol application produced a greater effect on accommodative convergence (AC) in stable myopic children who presumably have a more adequate, robust sympathetic input to the ciliary muscle, but had little effect on AC of progressing myopic children. This finding again points to the possibility that the autonomic control of the accommodation and convergence systems may be different between stable and progressing myopia. The primary contribution of this study to the understanding of myopia development is that differences in the autonomic control of the ciliary muscle may be responsible for producing anomalous accommodation responses. This could have significant impact on retinal image quality and thus results in myopia development. This knowledge may be incorporated into computer models of accommodation and myopia development and provides scope for further investigation of the therapeutic benefits of autonomic agents for myopia control.
72

Influência da Angiotensina-(1-7) na sensibilidade colinérgica cardíaca de ratos normotensos e hipertensos / Influence of Angiotensin-(1-7) in cardiac cholinergic sensitivity in normotensive and hypertensive rats

Pontes, Carolina Nobre Ribeiro 02 March 2018 (has links)
Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2018-10-03T11:24:00Z No. of bitstreams: 2 Dissertação - Carolina Nobre Ribeiro Pontes - 2018.pdf: 2152959 bytes, checksum: 9a1997dd7deceede7ede68d4550b490c (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2018-10-03T11:46:07Z (GMT) No. of bitstreams: 2 Dissertação - Carolina Nobre Ribeiro Pontes - 2018.pdf: 2152959 bytes, checksum: 9a1997dd7deceede7ede68d4550b490c (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-10-03T11:46:08Z (GMT). No. of bitstreams: 2 Dissertação - Carolina Nobre Ribeiro Pontes - 2018.pdf: 2152959 bytes, checksum: 9a1997dd7deceede7ede68d4550b490c (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2018-03-02 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Previous studies suggested that the Angiotensin-(1-7) [(Ang-(1-7)] is able to modulate the cardiac sympathetic control and beta-adrenergic sensitivity. However, whether or not Ang-(1- 7) modulates the cholinergic activity in the heart remains unknown. The aim of this study was to evaluate the influence of Ang-(1-7) upon cholinergic sensitivity of hearts from normotensive and hypertensive rats. Wistar and Spontaneously Hypertensive Rats (SHR) were anesthetized with urethane and underwent catheterization of femoral artery and left ventricle to record the arterial and intraventricular pressure, respectively. Following, a dose-response curve of acetylcholine (ACh, 10, 20, 40 and 80 ng/Kg, i.v. into femoral vein) was performed in the absence or presence of Ang-(1-7) (7 x 10-12 mol/min), Mas receptor antagonist A-779 (7 x 10-11 mol/min) or Ang-(1-7)+A-779. Isolated hearts were perfused according to the Langendorff technique. Increasing concentrations of ACh (10-7 to 10-5 mol/L) were added to the hearts in absence or presence of Ang-(1-7), (2 x 10-11 mol/L), A-779, (2 x 10-10 mol/L), Ang-(1-7)+A-779, MrgD receptor antagonist, D-PRO (2 x 10-10 mol/L) or D-PRO+Ang-(1-7). ACh-induced vasorelaxation was assessed in absence or presence of Ang-(1-7) (2 x 10-11 mol/L or 2 x 10-10 mol/L). Ang-(1-7) attenuated the effect of ACh in decreasing the intraventricular systolic, dP/dt max and dP/dt min in anesthetized Wistar and SHR. These effects were blocked by A-779. Ang-(1-7) did not change the amplitude of the hypotensive effect evoked by ACh in Wistar or SHRs. In isolated hearts, Ang-(1-7) also attenuated the reduction of the intraventricular systolic pressure, dP/dt max and dP/dt min evoked by ACh. A-779 blocked the Ang-(1-7) effects in hearts from Wistar. A-779 or D-PRO did not modify the effects of Ang-(1-7) in hearts from SHR, but in presence of D-PRO, Ang-(1-7) effects were equipotent. Ang-(1-7) attenuated the vasorelaxation induced by ACh in aorta from SHR by only in SHR group. These data suggest that Ang-(1-7) exerts differential modulation of cardiac cholinergic sensitivity during experimental primary hypertension, which is independent on blood pressure. / Estudos prévios sugerem que a Angiotensina-(1-7) [(Ang-(1-7)] é capaz de modular o controle simpático cardíaco e sensibilidade beta-adrenérgica. Entretanto, ainda não se sabe se a Ang-(1-7) consegue modular a atividade colinérgica no coração. O objetivo deste estudo foiavaliar a influência da Ang-(1-7) na sensibilidade colinérgica cardíaca de ratos normotensos e hipertensos. Wistar e Ratos Espontaneamente Hipertensos (SHR) foram anestesiados com uretano e submetidos à canulação de artéria femoral e ventrículo esquerdo cardíaco para registro de pressão arterial e intraventricular, respectivamente. Em seguida, foi realizada uma curva dose-resposta de acetilcolina (ACh, 10, 20, 40 e 80 ng/Kg, i.v.) por infusão pela veia femoral. A infusão ocorreu na presença e ausência de Ang-(1-7) (7 x 10-12 mol/min), do antagonista do receptor Mas, A-779 (7 x 10-11 mol/min) ou de Ang-(1-7)+A-779. Os corações isolados foram perfundidos de acordo com a técnica de Langendorff e concentrações crescentes de ACh (10-7 a 10-5 mol/L) foram adicionadas aos corações na presença ou ausência de Ang-(1-7), (2 x 10-11 mol/L), A-779, (2 x 10-10 mol/L), Ang-(1-7)+A-779, antagonista do receptor MrgD, D-PRO (2 x 10-10 mol/L) ou D-PRO+Ang-(1-7). O vasorrelaxamento induzido pela ACh foi mensurado na presença ou ausência da Ang-(1-7) (2 x 10-11 mol/L ou 2 x 10-10 mol/L). Em Wistar e SHR anestesiados, a Ang-(1-7) atenuou o efeito da ACh na queda da pressão intraventricular sistólica, dP/dt máx, e dP/dt mín. Estes efeitos foram bloqueados pelo A-779. A Ang-(1-7) não alterou a resposta hipotensora da ACh em Wistar ou SHR. Nos corações isolados, a Ang-(1-7) também atenuou a redução na pressão intraventricular sistólica, dP/dt máx e dP/dt mín evocados pela ACh. O A-779 bloqueou os efeitos da Ang-(1-7) em corações de Wistar. O A-779 ou D-PRO, per se, não modificaram os efeitos da Ang-(1-7) em corações de SHR, mas na presença do D-PRO, a Ang-(1-7) apresentou efeitos similares. O vasorrelaxamento da aorta induzido pela ACh foi atenuado pela Ang-(1-7) apenas nos SHR. Estes dados sugerem que a Ang-¬(1-¬7) modula o sistema colinérgico cardíaco de forma diferente no modelo de hipertensão primária experimental e de maneira independente de ajustes na pressão arterial.
73

Développement d’un nouvel indice reflet du bien être fœtal : le Fetal Stress Index / Development of a new index reflecting fetal wellbeing : the Fetal Stress Index

Garabedian, Charles 26 September 2017 (has links)
La surveillance du bien-être fœtal pendant le travail repose essentiellement sur l’enregistrement du rythme cardiaque fœtal (RCF). Celui-ci, même continu pendant le travail, ne permet pas d’évaluer parfaitement l’oxygénation du fœtus ni le risque d’asphyxie néonatale. En effet, cet outil est imparfait et son évaluation subjective avec une importante variabilité d’interprétation inter et intra opérateur. Des examens dits de seconde ligne sont utilisés en pratique courante pour caractériser l’état fœtal : le prélèvement de sang fœtal au scalp pour l’étude de l’équilibre acido-basique du fœtus (pH ou lactates) ou la pose d’électrode au scalp pour étudier l’ECG fœtal (analyse du segment ST). Ces techniques sont néanmoins invasives et sont soumises à des contraintes techniques. Il y a donc un intérêt à développer des moyens d’évaluation du bien être fœtal à la fois objectifs et non invasifs afin de diminuer la survenue d’une asphyxie périnatale. En effet, celle-ci touche 3 à 8 nouveaux nés pour 1000 naissances. La mortalité en période post-natale est de 25 à 50% des cas et ceux qui survivent développeront des troubles sévères (épilepsie, retard neuro-cognitif et comportemental, paralysie cérébrale…). Au cours de l’accouchement, l’asphyxie périnatale se caractérise par une diminution du pH artériel ombilical. Cette mesure du pH sanguin est donc la mesure de référence pour déterminer la sévérité de l’asphyxie.Une des voies étudiées pour améliorer le dépistage des fœtus à risque d’acidose est l’analyse des modifications du système nerveux autonome (SNA) par analyse de la variabilité du rythme cardiaque fœtal. En effet, la fréquence cardiaque fœtale est en permanence sous l’influence du système nerveux autonome et sa variabilité (VFC) est un reflet de la balance sympathique / parasympathique. Le CHU de Lille a développé une nouvelle méthode d’analyse continue de la VFC ayant montré son efficacité chez l’adulte et chez le nouveau né pour l’évaluation du SNA. L’objectif de ce travail de Thèse est d’adapter cette technologie à l’analyse du SNA fœtal pour obtenir un nouvel indice appelé Fetal Stress Index (FSI) et d’évaluer sa pertinence en situation d’acidose.Cette preuve de concept a été effectuée de manière expérimentale chez le fœtus de brebis. Elle s’est réalisée en 2 temps. Nous avons tout d’abord évalué la performance du FSI par rapport aux méthodes classiques d’analyse de la VFC en termes d’aptitude à détecter les variations du SNA. Après injection d’Atropine, parasympatholytique, ou de Propranolol, sympatholytique, nous avons montré que le FSI était une méthode efficace et spécifique d’évaluation des variations du tonus parasympathique du SNA. Cette étude a également montrée la supériorité du FSI par rapport aux méthodes classiques d’analyse de la VFC en termes de sensibilité et de spécificité. Dans un second temps, nous avons évalué ce nouvel indice comme facteur prédictif de l’état acido basique du fœtus dans 2 modèles expérimentaux d’occlusion cordonale. Dans le premier modèle, l’acidose était obtenue par une occlusion continue du cordon avec une réduction de partielle du débit ombilical. Dans le second, nous réalisions des occlusions totales répétées à intervalles réguliers afin de mimer les contractions utérines lors du travail. Dans les 2 études, nous avons observé une hausse du FSI en cas d’acidose avec une corrélation significative entre le FSI et le pH, mais aussi entre le FSI et les lactates dans le second modèle.En conclusion, le FSI constitue un bon reflet de l’activité parasympathique fœtale. Cet indice permet d’étudier les variations du SNA fœtal avec une meilleure sensibilité et une meilleure spécificité que les méthodes usuelles d’analyse de la VFC et semble bien corrélé à l’état acido basique fœtal. Il s’agit donc d’un indice prometteur qu’il sera intéressant d’incorporer dans une analyse multi paramétrique du rythme cardiaque fœtal. / The monitoring of fetal well being during labor is essentially based on fetal heart rate (FHR) analysis. The recording of FHR, even continuously during labor, does not fully assess fetal oxygenation or neonatal risk of asphyxia. Indeed, this tool is imperfect and subjective with an important inter and intra-operator variability. Second-line examinations to characterize the fetal state are currently used in routine practice, i.e. scalp fetal blood sampling to study the fetal acid-base balance (pH or lactates) or scalp electrode placement to study the fetal ECG (ST segment analysis). These techniques are nevertheless invasive and subject to technical constraints. There is therefore an interest in developing both objective and non-invasive means of evaluating fetal wellbeing to reduce neonatal encephalopathy. Indeed, its prevalence is about 3 to 8 per 1000 births. Post natal mortality is about 25 to 50% and survivors will hav severe diseases (epilepsy, neurologic impairment, cerebral palsy…).One of the possibilities studied to better identify fetuses at risk for acidosis is the analysis of changes in the autonomic nervous system (ANS) in response to hypoxia.Indeed, the regulation of heart rate is dependent on the ANS and thus, its variability is a reflection of the sympathetic / parasympathetic balance. Analysis of heart rate variability (HRV) is a recognized non-invasive tool that is used to assess ANS regulation. The CHU Lille has developed a new continuous tool for the analysis of HRV, which demonstrated its efficacity in adults and neonates to evaluate the ANS. The objective of this thesis was to develop its index, called Fetal Stress Index (FSI), in the fetus and to evaluate it in conditions of acidosis.The study was experimental in a sheep model chronically instrumented and was in 2 steps. First, we evaluate the performance of our method compared to commonly used HRV analysis, regarding the ability to detect the variation of variations of the ANS. After injection of atropine, to inhibit parasympathetic tone, or propranolol to block sympathetic activity, we shown that our method appeared to be effective in detecting parasympathetic inhibition and, moreover, was superior to classical analysis of HRV in terms of sensibility and specificity.In a second time, we evaluated this new index as a predictive factor of the fetal acid-base state in 2 experimental models of fetal hypoxia by occlusion of the cord. In the first one, acidosis was obtained through a partial occlusion of the umbilical cord and in the second one, though repetitive complete occlusion as uterine contractions during labor. In those two studies, we observed a raise of our index in case of acidosis with a correlation beetween FSI and pH and also FSI and lactates in the second model.In conclusion, the FSI reflects fetal parasympathetic activity, has a better detection than others usual methods, and seems well correlated to fetal acid-base status. It is a promising index and it will be interesting to incorporate it in a multi parametric analysis of fetal heart rate to predict acidosis.
74

Evaluation et prévention des états de stress et de récupération du sportif : suivi psychophysiologique et processus cognitivo-affectif / Athletes stress and recovery monitoring and prevention : psychophysiological monitoring and cognitive-affective process

Vacher, Philippe 02 December 2016 (has links)
Le suivi et la compréhension des états de stress et de récupération des sportifs est un enjeu majeur, notamment dans le cadre de périodisations complètes de l’entraînement. Un déséquilibre mal maîtrisé entre le stress et la récupération peut induire une fatigue voire un épuisement psychologique et physiologique du sportif. Il en découlera des conséquences néfastes sur le bien-être et la santé de la personne mais également sur la performance individuelle et collective. Ces conséquences sont complexes et impliquent des dimensions environnementales, sociales, psychologiques et physiologiques non-spécifiques. Enfin, ces symptômes sont soumis à des variations intra et interindividuelles importantes rendant le diagnostic d’autant plus complexe à établir. En s’appuyant sur plusieurs suivis de sportifs en pôle « Espoir », ce travail de recherche montre l’évolution de variables psychologiques et physiologiques intervenant dans la réponse au stress chez le sportif. Ces travaux permettent également de mettre en évidence des variables prédictives des états de stress et de récupération. Enfin, nous démontrons que les états de stress et de récupération des sportifs impactent les états émotionnels au niveau intra et interindividuel. / Monitoring stress and recovery states is a key issue, especially in high performance sport. An imbalance between stress and recovery can induce fatigue, psychological and physiological exhaustion. Thus, negative consequences on well-being, health and individual and collective performance can be experienced. These consequences are complex as they stem from non-specific environmental, social, psychological and physiological dimensions. These phenomena are subject to important intra-individual and inter-individual variations, which make a diagnosis hard to establish. Based on a several followings of athletes from high performance structures, this research shows the evolution of psychological and physiological variables intervening as a response to stress. From these studies, some predictive variables also showed up in predicting stress and recovery states. Finally, we made evidence of the impact of athletes’ stress and recovery states on emotional states, on the intra and inter-individual levels.
75

Temporal Dynamics of the Defense Cascade

Nackley, Brittany B. January 2020 (has links)
Understanding physiological responses to threat can inform therapeutic interventions for phobias, anxieties, and PTSD. The defense cascade is reviewed as a theoretical model that predicts behavioral and physiological responses to threats. Nineteen undergraduates (five male), average age 19.4 experienced a novel virtual reality (VR) threat scenario while their physiology was measured. The Subjective Units of Distress Scale (SUDS) was used as a self-report indicator of distress in the research setting. Averaged SUDS reports suggested that the VR stimulus was experienced as threatening for most participants, but their autonomic response patterns did not fit those predicted by the defense cascade. Participants who had scored high on adaptive response questionnaires tended to show uncoupled ANS activation during baseline, but varied across the stimulus condition. Nearly all participants showed either coactivation or reciprocal activation during the stimulus period except those reporting the most dissociative trauma experiences, who mostly showed uncoupled ANS activation. / M.S. / The more we understand about how people’s bodies and their energies act when they feel threatened, the better we can find help for folks who struggle with anxiety, trauma or other challenging conditions. This research uses a theoretical model called the defense cascade to explore how people respond mentally and physically to threatening situations. Nineteen undergraduates went through a virtual reality (VR) experience that was designed to feel threatening while their body and its energy systems were measured. A scale was introduced called the Subjective Units of Distress Scale (SUDS) and was used to help the researchers understand how distressed people felt while they were in the VR experience. Averaged SUDS reports suggested that the VR stimulus was experienced as threatening for most participants, but their body response patterns did not fit those predicted by the defense cascade. Participants whose questionnaire responses suggested they were not anxiety-prone or traumatized, tended to show bodily activation that uncoupled their two autonomic bodily systems during a baseline period before the threatening stimulus. However, their autonomic responses during the stimulus period varied. Nearly all participants showed either both autonomic systems acting together or only one system acting in a mutually exclusive way to the other system during the stimulus period. This was the case for most participants except those reporting the most trauma involving dissociative experiences. This latter group mostly showed uncoupled autonomic bodily patterns.
76

Modulação autonômica cardíaca em crianças e adolescentes com anemia falciforme / Cardiac autonomic modulation in children and adolescents with sickle cell anemia- doctoral thesis

Ribera, Melissa Chaves Vieira 18 April 2017 (has links)
Introdução - Alterações cardíacas na anemia falciforme (AF) são frequentes e iniciam-se precocemente. Há evidências de que exista também disfunção na regulação do sistema nervoso autônomo o que pode contribuir com eventos de morbidade. Objetivos Avaliar a modulação autonômica cardíaca por meio da variabilidade da frequência cardíaca em crianças e adolescentes com anemia falciforme. Método - Estudo analítico no qual foi realizada uma comparação da variabilidade da frequência cardíaca em 45 crianças e adolescentes, menores de 20 anos, com anemia falciforme, com um grupo controle pareado um a um por idade e sexo. A frequência cardíaca foi obtida pelo frequencímetro de pulso e analisada, batimento a batimento. Estes pacientes são usuários do ambulatório de hematologia pediátrica do Sistema Único de Saúde. Esta pesquisa está em consonância com a resolução 466/2012 do Ministério da Saúde. Resultados - Observamos diferença significativa nos índices do domínio da frequência (VLF, LF, HF e LF/HF). Estas diferenças não foram observadas nos pacientes em uso de hidroxiureia. Conclusão - Existe uma disfunção autonômica na AF que ocorre desde a infância, podendo estar relacionada a uma menor modulação do simpático e uma maior modulação do parassimpático. Esta diferença não foi observada em pacientes em uso de hidroxiureia / Introduction - Cardiac changes in sickle cell disease (AF) are frequent and begin early. There is evidence that there is also dysfunction in the regulation of the autonomic nervous system, which may contribute to morbidity events. Objectives - To evaluate the autonomic cardiac modulation by heart rate variability in children and adolescents with sickle cell anemia. Method - An analytical study comparing the heart rate variability of 45 children and adolescents, younger than 20 years, with sickle cell anemia, with a control group matched one by one by age and sex. The heart rate was obtained by pulse frequency and analyzed, beat by beat. These patients are attending the pediatric hematology outpatient of the National Health System. Results - We observed a significant difference in the frequency domain indexes (VLF, LF, HF and LF / HF). The results of this study are in agreement with resolution 466/2012 of the Ministry of Health of Brazil. These differences were not observed in patients taking hydroxyurea. Conclusion - There is an autonomic dysfunction in AF that occurs from childhood, and may be related to a lower modulation of the sympathetic and greater modulation of the parasympathetic. This difference was not observed in patients taking hydroxyurea
77

Relação entre componentes de sintomas depressivos e variabilidade de frequência cardíaca / Relationship between components of depressive symptoms and heart rate variability

Borrione, Lucas 19 October 2017 (has links)
INTRODUÇÃO: O transtorno depressivo maior (TDM) está associado à doença cardiovascular (DCV), possivelmente por alterações no sistema nervoso autônomo (SNA), dentre outros mecanismos. Um dos marcadores de atividade do SNA mais estudados na literatura é a variabilidade de frequência cardíaca (VFC), um índice de variação entre batimentos cardíacos. VFC elevada é sinal de um SNA saudável, enquanto VFC diminuída reflete inflexibilidade autonômica. Alguns estudos têm relatado uma relação entre o TDM e VFC reduzida, enquanto outros não confirmaram esses achados. Além de fatores de confusão, uma possível explicação para esta inconsistência é a complexidade da síndrome depressiva, composta por sintomas de vários domínios. Logo, alguns sintomas podem estar associados com VFC reduzida, enquanto outros portam nenhuma associação. Consequentemente, quando todos os sintomas são avaliados simultaneamente, as associações de sintomas depressivos específicos com VFC não seriam identificadas. Este estudo teve como objetivo investigar a relação entre VFC e componentes de sintomas depressivos a partir de dados de estudo previamente realizado na Universidade de São Paulo, entre 2010 e 2011. MÉTODOS: Neste estudo, foram analisados dados de 120 pacientes com TDM, com baixo risco de DCV, coletados na avaliação basal de um ensaio clínico duplo-cego e randomizado, avaliando o uso da estimulação transcraniana por corrente contínua versus cloridrato de sertralina para tratar o TDM. Para avaliação da gravidade do TDM, foram utilizadas a Escala de Depressão de Hamilton (HAM-D-17), a Escala de Depressão de MontgomeryÅsberg (MADRS) e o Inventário de Depressão de Beck-IA (BDI-IA). Os componentes de sintomas depressivos foram extraídos de cada escala através de análise de componentes principais. Para avaliar a VFC, foram utilizados 4 parâmetros: a raiz quadrada da média do quadrado das diferenças entre intervalos R-R normais adjacentes (RMSSD, ou root mean square of successive differences), alta frequência (HF, ou high frequency), baixa frequência (LF, ou low frequency) e baixa frequência/alta frequência (LF/HF, ou low frequency/high frequency), computados a partir de segmento de eletrocardiograma de 15 minutos de duração, em repouso. Para investigar a associação dos 4 parâmetros de VFC com os componentes de sintomas depressivos de cada escala, construíram-se equações de regressão linear múltipla, incluindo em cada equação um parâmetro de VFC como variável dependente e os componentes de sintomas depressivos das três escalas como variáveis independentes. O modelo foi ajustado para idade e gênero. Utilizouse o procedimento stepwise backward para atingir o modelo final, mantendo-se variáveis com p < 0,10. RESULTADOS: Baseando-se em análise de scree plot, foram extraídos 6 componentes da HAM-D-17, 2 da MADRS e 3 da BDI-IA. Após controle para idade e gênero, a análise por regressão linear múltipla revelou que o componente 4 da HAM-D-17 (humor depressivo, sentimentos de culpa, suicídio e trabalho e atividades) foi preditor de LF/HF e o componente 2 da MADRS (dificuldades de concentração, lassidão, incapacidade para sentir e pensamentos pessimistas) foi preditor de LF. CONCLUSÕES: Os resultados deste estudo corroboram a hipótese que a presença de certos componentes de sintomas depressivos, mas não todos, estão associados com mudanças na VFC. Não houve correção de significância estatística para múltiplas comparações, devendo este estudo ser considerado de natureza exploratória / INTRODUCTION: Major depressive disorder (MDD) is associated with cardiovascular disease (CVD), possibly due to impairments in the autonomic nervous system (ANS), among other mechanisms. One of the most studied markers of ANS activity is heart rate variability (HRV), an index of beat-to-beat variations in heart rate. High HRV is an indicator of a healthy ANS, while low HRV denotes autonomic inflexibility. Some studies have reported a relationship between MDD and low HRV, while others have not confirmed such findings. A possible explanation for this inconsistency is the complexity of the depressive syndrome, which is composed by symptoms from various domains. Therefore, some symptoms might be associated with low HRV, while others bear no association. Consequently, when all symptoms are evaluated simultaneously, the association of HRV with specific depressive symptoms might go unnoticed. This study aimed to investigate the relationship between HRV and components of depressive symptoms, using data of a previous study done in the University of São Paulo, between 2010 and 2011. METHODS: In this study, data from 120 patients with MDD and low risk for CVD was assessed at the baseline of a randomized, controlled clinical trial, performed to evaluate the use of transcranial direct current stimulation versus sertraline chloridrate in in the treatment of MDD. The Hamilton Rating Scale for Depression (HAM-D-17), the Montgomery-Åsberg Depression Rating Scale (MADRS) and the Beck Depression Inventory-IA (BDI-IA) were used to assess depressive symptoms. The components of depressive symptoms were extracted from each scale by principal component analysis. For the evaluation of HRV, the following 4 parameters were used: root mean square of the successive differences (RMSSD), high frequency (HF), low frequency (LF), and low frequency/high frequency (LF/HF). These parameters were computed through a 15-minute electrocardiogram at rest. For the investigation of the association between the 4 HRV parameters and the components of depressive symptoms of each scale, multiple linear regression equations were built, including in each equation a parameter of HRV as the dependent variable and the components of depressive symptoms from the three scales as the independent variables. The model was adjusted for age and gender. A stepwise backward procedure was used to attain the final model, and only variables with p < 0.10 were kept. RESULTS: Based on scree plot analyses, HAM-D-17 yielded 6 components, MADRS 2 components and BDI-IA, 3 components. After adjusting for age and gender, multiple linear regression analyses revealed that LF/HF was predicted by HAM-D-17 Component 4 (depressed mood, feelings of guilt, suicidal thoughts and work and activities) and LF was predicted by MADRS Component 2 (concentration difficulties, lassitude, inability to feel and pessimistic thoughts). CONCLUSIONS: The results of this study support the hypothesis that certain components of depressive symptoms, and not all of them, are associated with a change in HRV. There was no correction of statistical significance for multiple comparisons, and this study should be considered of exploratory nature
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Inervação autonômica da articulação temporomandibular em condições de normalidade e, padrão de ativação neuronal no tronco encefálico durante a vigência de artrite no complexo articular temporomandibular. / Temporomandibular joint autonomic innervation inder normal conditions and, neuronal activation pattern in the brain stem during monoarthritis induced in the temporomandibular joint complex.

Ervolino, Edilson 10 August 2009 (has links)
Os objetivos do presente trabalho foram: 1) analisar a distribuição das fibras nervosas autonômicas na articulação temporomandibular (ATM) do rato, através da detecção de tirosina hidroxilase (TH), neuropeptídeo Y (NPY) e peptídeo intestinal vasoativo (VIP); 2) realizar um estudo topográfico ultra-estrutural das fibras e terminações nervosas autonômicas na ATM do rato; 3) determinar o padrão de ativação neuronal no complexo nuclear trigeminal e, em centros nervosos moduladores da dor, durante a vigência de monoartrite no complexo articular temporomandibular (CATM) do rato. Para o primeiro propósito o método imunoistoquímico, para a detecção simultânea de TH, NPY e VIP, foi executado em ATMs que apresentavam as seguintes condições: inervação intacta ou desprovida de inervação simpática e/ou parassimpática. Para o segundo propósito aliamos o tratamento prévio com 5-hidroxidopamina, para evidenciação de terminações nervosas simpáticas, com a remoção cirúrgica do gânglio ótico, para a visualização das fibras e terminações nervosas parassimpáticas em degeneração, em seguida analisamos as ATMs ao microscópio eletrônico de transmissão. O terceiro propósito foi obtido induzindo-se monoartrite (fase aguda, crônica e crônica ativa) no CATM e, verificando a expressão de Fos, um marcador de ativação neuronal, no complexo nuclear sensorial trigeminal e nos principais centros nervosos moduladores da dor, situados no tronco encefálico (substância cinzenta periaqueductal- PAG; área rostral ventromedial da medula oblonga- RVM; locus coeruleus- LC; área caudal ventrolateral da medula oblonga- CVLM; núcleo do trato solitário- NTS e; núcleo reticular ventral-NRV). Verificamos que as ATMs desprovidas de inervação simpática apresentam exclusivamente uma pequena quantidade de fibras nervosas VIP-IR, ao passo que aquelas desprovidas de inervação parassimpática mostram uma grande quantidade de fibras nervosas TH/NPY-IR e TH/NPY/VIP-IR. As fibras e terminações nervosas autonômicas foram observadas em vasos sanguíneos ou isoladas no tecido conjuntivo, especialmente na membrana sinovial. No que se refere à expressão de Fos, constatamos que o subnúcleo caudal do núcleo do tracto espinal do nervo trigêmeo (Sp5C) e a PAG apresentaram um aumento bilateral significante na expressão de Fos durante todas as fases da monoartrite induzida no CATM. Todavia, RVM, LC, CVLM, NTS apresentaram uma quantidade de neurônios Fos-IR significativamente aumentada, de ambos os lados, apenas quando o CATM estava sob vigência de monoartrite na fase aguda e crônica ativa. Concluímos que: 1) a ATM mostra-se densamente inervada por fibras nervosas simpáticas (TH/NPY-IR e TH/NPY/VIP-IR) e, por uma discreta quantidade de fibras nervosas parassimpáticas (VIP-IR), ambas predominantemente associadas com vasos sanguíneos; 2) o Sp5C e a PAG, mostra-se intensamente ativados em todas as fases da monoartrite no CATM, ao passo que a maioria dos centros nervosos moduladores da dor apresentam uma quantidade aumentada de neurônios imunoarreativos ao marcador de ativação neuronal, Fos, apenas durante as fases aguda e crônica ativa dessa monoartrite. / The goals of the present study were: 1) to analyse the distribution of autonomic nerve fibers in the rat temporomandibular joint (TMJ) under normal conditions using immunofluorescence method to detect tirosyne hydroxylase (TH), neuropetide Y (NPY) and vasoactive intestinal polypeptide (VIP); 2) to verify the detailed distribution of autonomic nerve fibers in the rat temporomandibular joint by transmission electron microscopy; 3) to determine the neuronal activation pattern in the trigeminal system and in the pain modulation centers during monoarthritis induced in the rat temporomandibular joint complex (TMJC). For the first purpose, histologic sections from TMJs with intact innervation or with surgical sympatectomy and/or parasympathectomy were submitted to simultaneous detection of TH, NPY and VIP. For the second purpose, 5-hydroxidopamine treatment to detect sympathetic nerve endings was combined with surgical parasympatectomy of the otic ganglion to detect degenerated parasympathetic nerve endings in the rat TMJC, by transmission electron microscopy. For the last purpose, monoarthritis (acute, chronic and chronic-active phases) was induced in the TMJC and histologic sections from the brain stem were submitted to immunodetection of Fos protein in the trigeminal system and in the pain modulation centers (periqueductal gray matter - PAG; rostroventromedial medulla - RVM; locus coeruleus- LC; caudal ventrolateral medulla- CVLM; nucleus of the solitary tract - NTS; ventral reticular nucleus - VRN). The most important results demonstrated that the TMJC showed a discrete parasympathetic innervation (VIP-IR), while the sympathetic innervation was dense and characterized by TH-/NPY-/VIP-IR or TH-/NPY-IR nerve fibers. Autonomic nerve fibers were mainly noted associated to blood vessels and occasionally disperse in the synovial membrane. Fos-IR neurons showed significant bilateral increase in the spinal trigeminal caudal subnucleus and PAG during arthritis evolution. On the other hand, RVM, LC, CVLM and NTS only showed significant increase of Fos-IR neurons during the acute and chronic-active phases of monoarthritis. The main conclusions were: 1) the TMJC shows a dense sympathetic innervation (TH/NPY-IR or TH-/NPY-/VIP-IR) and discrete parasympathetic innervation (VIP-IR), both associated mainly to blood vessels; 2) most modulation pain centers are activated principally during acute and chronic-active arthritis, while the spinal trigeminal caudal subnucleus and PAG showed continuous activation during all phases of arthritis.
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Modulação autonômica cardíaca em crianças e adolescentes com anemia falciforme / Cardiac autonomic modulation in children and adolescents with sickle cell anemia- doctoral thesis

Melissa Chaves Vieira Ribera 18 April 2017 (has links)
Introdução - Alterações cardíacas na anemia falciforme (AF) são frequentes e iniciam-se precocemente. Há evidências de que exista também disfunção na regulação do sistema nervoso autônomo o que pode contribuir com eventos de morbidade. Objetivos Avaliar a modulação autonômica cardíaca por meio da variabilidade da frequência cardíaca em crianças e adolescentes com anemia falciforme. Método - Estudo analítico no qual foi realizada uma comparação da variabilidade da frequência cardíaca em 45 crianças e adolescentes, menores de 20 anos, com anemia falciforme, com um grupo controle pareado um a um por idade e sexo. A frequência cardíaca foi obtida pelo frequencímetro de pulso e analisada, batimento a batimento. Estes pacientes são usuários do ambulatório de hematologia pediátrica do Sistema Único de Saúde. Esta pesquisa está em consonância com a resolução 466/2012 do Ministério da Saúde. Resultados - Observamos diferença significativa nos índices do domínio da frequência (VLF, LF, HF e LF/HF). Estas diferenças não foram observadas nos pacientes em uso de hidroxiureia. Conclusão - Existe uma disfunção autonômica na AF que ocorre desde a infância, podendo estar relacionada a uma menor modulação do simpático e uma maior modulação do parassimpático. Esta diferença não foi observada em pacientes em uso de hidroxiureia / Introduction - Cardiac changes in sickle cell disease (AF) are frequent and begin early. There is evidence that there is also dysfunction in the regulation of the autonomic nervous system, which may contribute to morbidity events. Objectives - To evaluate the autonomic cardiac modulation by heart rate variability in children and adolescents with sickle cell anemia. Method - An analytical study comparing the heart rate variability of 45 children and adolescents, younger than 20 years, with sickle cell anemia, with a control group matched one by one by age and sex. The heart rate was obtained by pulse frequency and analyzed, beat by beat. These patients are attending the pediatric hematology outpatient of the National Health System. Results - We observed a significant difference in the frequency domain indexes (VLF, LF, HF and LF / HF). The results of this study are in agreement with resolution 466/2012 of the Ministry of Health of Brazil. These differences were not observed in patients taking hydroxyurea. Conclusion - There is an autonomic dysfunction in AF that occurs from childhood, and may be related to a lower modulation of the sympathetic and greater modulation of the parasympathetic. This difference was not observed in patients taking hydroxyurea
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The connection between emotion, brain lateralization, and heart-rate variability /

Newell, Miranda E. January 2005 (has links) (PDF)
Thesis (M.S.)--Uniformed Services University of the Health Sciences, 2005. / Typescript (photocopy).

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