Thesis (Ph.D.)--George Mason University, 2008. / Vita: p. 83. Thesis director: Juan R. Cebral. Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Computational Sciences and Informatics. Title from PDF t.p. (viewed Aug. 27, 2008). Includes bibliographical references (p. 78-82). Also issued in print.

Thesis (Ph.D.)--George Mason University, 2008. / Title from PDF t.p. (viewed Oct. 14, 2008). Thesis director: Juan R. Cebral. Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Computational Sciences and Informatics. Vita: p. 98. Includes bibliographical references (p. 90-97). Also available in print.

Thesis (M.S.)--University of Michigan, 2003. / Includes bibliographical references.

Thesis (M. Med. Sc.)--University of Hong Kong, 1999. / Includes bibliographical references (leaves 48-62).

Thesis (M.Med.Sc.)--University of Hong Kong, 1999. / Includes bibliographical references (leaves 48-62). Also available in print.

Orientador: Pedro Thadeu Galvão Vianna / Banca: Eneida Maria Vieira / Banca: José Otávio da Costa Auler Junior / Banca: Moacir Fernandes de Godoy / Banca: Yara Marcondes Machado Castiglia / Resumo: Foi realizado estudo experimental em coração isolado de coelhos, perfundido pelo método de Langendorff, para avaliar o efeito da cetamina S(+) associada à cardioplegia sangüínea, durante e na manutenção por 30 minutos de parada cardíaca, conforme critérios hemodinâmicos e morfológicos. Foram utilizados 50 coelhos da linhagem Norfolk-2000, pesando 1850 a 2350 g, divididos em três grupos de corações isolados: Grupo C (n=10) cardioplegia sangüínea; Grupo CC (n=10) cetamina S(+) associada à cardioplegia sangüínea e, Grupo PA (n=5) parada cardíaca anóxica. A função ventricular foi analisada pela técnica de balão intraventricular. Fragmentos de um único ventrículo esquerdo foram analisados como padrão de normalidade histopatológica. A análise estrutural e ultra-estrutural de fragmentos do ventrículo esquerdo após a parada cardíaca imediata por cardioplegia ou anóxica, seguida por período de manutenção. Foram obtidos os seguintes resultados: 1. Avaliação hemodinâmica. Pressão desenvolvida intraventricular (PDes): grupo C (76,39±17,69 mmHg e 62,08±32,13 mmHg) p <0,05; grupo CC (89,26±16,37 mmHg e 52,62±24,91 mmHg) p<0,05; grupo PA (77,96±12,67 mmHg e 60,81±29,68 mmHg), pré e pós-tratamento, respectivamente. Primeira derivada temporal da pressão ventricular na sua deflexão positiva (dP/dt+): grupo C (1236±181,15 mmHg/seg e 1150,20±174,44 mmHg/seg); grupo CC (1372,61±214.19 mmHg/seg e 1058,52±255,10 mmHg/seg) p<0,05; grupo PA (1252,39±99,76 mmHg/seg e 1115,10±73,07 mmHg/seg), pré e pós-tratamento, respectivamente. Primeira derivada temporal em sua deflexão negativa (dP/dt-): grupo C (856,01±132,26 mmHg/seg e 783,62±177,54 mmHg/seg); grupo CC (948,11±106,34 mmHg/seg e 760,28±219,37 mmHg/seg); grupo PA (911,02±74,53 mmHg/seg e 818,95±219,09 mmHg/seg), pré e pós-tratamento, respectivamente. 2. Avaliação morfológica. / Abstract: An experimental study in isolated heart of rabbits, perfused by the Langendorff system, to evaluate the effect of S(+) ketamine associated with blood cardioplegia during and in the maintenance during 30 minutes of the cardiac arrest according to hemodynamic and morphological criteria. A total of 50 Norfolk-2000 rabbits, weighting 1850 to 2350 g, were divided into three groups of isolated hearts: blood cardioplegia-BC (n=10); S(+) ketamine associated with blood cardioplegia-K (n=10), and anoxic cardiac arrest-CA (n=5). The ventricular function was analyzed by the intra-ventricular balloon technique. The structural and ultrastructural analysis of fragments of the left ventricle after immediate cardiac arrest by cardioplegia or anoxic arrest, followed by maintenance period. The fragments of the left ventricle were analyzed as pattern of histopathological normality. The following results were obtained: 1. Hemodynamic evaluation. Intra-ventricular developed pressure (IVDP) was: group BC (76.39±17.69 mmHg and 62.08±32.13mmHg) p<0.05; group K (89.26±16.37mmHg and 52.62±24.91mmHg) p<0,05; group CA (77.96±12.67mmHg and 60.81±29.68mmHg), pre and posttreatment, respectively. First derivative of intraventricular pressure in its positive deflection (dP/dt+) was: group BC (1236±181.15 mmHg/sec and 1150.20±174.44 mmHg/seg); K (1372.61±214.19 mmHg/sec and 1058.52±255.10mmHg/seg) p<0.05; CA (1252.39±99.76 mmHg/sec and 1115.10±73.07 mmHg/sec), pre and posttreatment, respectively. First derivate pressure in its negative deflection (dP/dt-) was: group BC (856.01±132.26 mmHg/sec and 783.62±177.54 mmHg/sec); K (948.11±106.34 mmHg/sec and 760.28±219.37 mmHg/sec); CA (911.02±74.53 mmHg/sec and 818.95±219.09 mmHg/sec) pre and posttreatment, respectively. 2. Morphological evaluation. / Doutor

The objective was to examine effects of melatonin supplementation during late gestation on uterine artery hemodynamics, offspring growth, and endocrine profiles. Prior to day 170 of gestation, heifers were trained to the Calan feeding system. On day 190 of gestation, heifers (n = 20) were blocked by BW and then randomly assigned to one of two dietary treatments: 1) 20 mg of dietary melatonin per day (MEL) or 2) no melatonin supplementation (CON). Supplementation ceased on day 262 of gestation. A main effect (P < 0.01) of treatment was observed for total uterine artery blood flow with it being increased in MEL vs. CON. An interaction (P = 0.008) was observed in calf body weight increasing at weeks 8 and 9 in MEL vs. CON. Dietary melatonin could be used to potentially increase uterine blood flow and calf body weight.

No description available.

Background. Stroke affects over 80 million individuals worldwide. Elevated arterial stiffness has emerged as a novel independent risk marker for stroke. While arterial stiffness is improved after chronic aerobic training, a single bout of aerobic exercise leads to transient increases that typically resolve within 5 minutes of recovery. Elevated arterial stiffness may persist for up to 30 minutes following exercise in populations with cardiovascular disease. However, no study has examined the effect of acute aerobic exercise on arterial stiffness and central hemodynamics in individuals with stroke. Moreover, no study has explored the clinical significance of these responses. Objectives. The primary objective of this thesis was to characterize the response and recovery of arterial stiffness and central hemodynamics to peak aerobic exercise in individuals ≥ 6 months post-stroke. The secondary objective was to explore the relationships between the exercise response and recovery of arterial stiffness and central hemodynamics, with cardiorespiratory fitness and walking ability. Results. This cross-sectional study recruited 10 adults with stroke (mean ± SD age=56.9 ± 11.8; median [IQR]= 2.9 [1.9] years post-stroke; n=4 females). After peak aerobic exercise, cfPWV increased from rest and remained elevated for 20 minutes (p<0.05). Heart rate increased and remained elevated for 10 minutes post-exercise (p<0.05), while systolic blood pressure decreased and remained reduced for 15 minutes (p<0.05). Positive associations were found between cardiorespiratory fitness and heart rate reserve (r=0.74, p=0.02), and with each phase of heart rate recovery (HR60s r=0.80, p=0.005, HR120s r=0.79, p=0.006; HR300s r=0.72, p=0.02; and HR600s r=0.75, p=0.01). There were no relationships between response and recovery of hemodynamic variables with walking ability. Conclusion. Individuals with chronic stroke may have impaired arterial stiffness and heart rate recovery following peak aerobic exercise. Moreover, heart rate reserve and all phases of heart rate recovery were related to cardiorespiratory fitness, but not walking ability. / Thesis / Master of Science Rehabilitation Science (MSc) / Arterial stiffness has been recently identified as an important risk marker for stroke. Aerobic exercise reduces the risk of stroke by lowering arterial stiffness. But during exercise, there is an increase in arterial stiffness that usually subsides by 5 minutes. Lengthy exposure to arterial stiffness can cause damage to organs like the kidneys and liver. The purpose of this thesis was to measure the arterial stiffness and cardiovascular response to exercise in people with stroke. We also studied the relationship between the responses, fitness and walking ability. Ten people with stroke participated in this study. After aerobic exercise, arterial stiffness stayed high above resting levels and did not recover after 20 minutes. Also, heart rate recovery was related to fitness but not walking ability. This study tells us that people with stroke have an weakened ability to recover from aerobic exercise and that higher fitness levels can improve exercise recovery.

published_or_final_version / Mechanical Engineering / Master / Master of Philosophy