Thesis (M.S.)--Ball State University, 2009. / Title from PDF t.p. (viewed on Apr. 16, 2010). Includes bibliographical references.

Thesis (M.S.)--Springfield College, 2005. / Includes bibliographical references. Also available online (PDF file) by a subscription to the set or by purchasing the individual file.

Thesis (M.S.)--Springfield College, 2005. / Includes bibliographical references.

<b>Background</b> Cardiovascular risk scores are used to estimate absolute risk of disease and identify patients who will benefit most from treatments to lower risk. As a key risk factor for cardiovascular disease, blood pressure is accounted for in many risk scores, but is inherently variable and may be influenced by both biological and measurement factors. This thesis aims to determine how routinely collected blood pressure measurements should best be used for accurate estimation of cardiovascular risk. <b>Methods</b> This thesis describes four main studies. A patient survey and prospective study establish the current practice of blood pressure measurement. Secondary analyses of data from blood pressure monitoring trials determine how risk estimates may be affected by the use of different summary measures of blood pressure. A systematic review evaluates the evidence of an association between blood pressure variability and cardiovascular risk. Finally, a cohort study in the Clinical Practice Research Datalink determines if inclusion of blood pressure variability in cardiovascular risk scores may improve risk estimation. <b>Results</b> Current practice of blood pressure measurement may differ from that in risk score derivation studies. However, these differences have limited effects on cardiovascular risk estimates with few patients reclassified across risk thresholds. Increased long-term variability in blood pressure is in itself a risk factor for cardiovascular disease over and above mean blood pressure but its inclusion in a cardiovascular risk score does not materially improve the accuracy of risk estimates. <b>Conclusions</b> Healthcare professionals should continue to estimate risk for primary prevention of cardiovascular disease using the blood pressure measurements available to them, whether measured at home or in the clinic. There is also no additional benefit of considering measures of long-term blood pressure variability in risk estimation.

A hipertensão arterial sistêmica (HAS) é uma condição clínica multifatorial que acomete parte significativa da população mundial sendo sua prevalência no diabetes melito (DM) mais elevada do que na população em geral. Modificações no estilo de vida, entre elas intervenções dietoterápicas são importantes ferramentas para a prevenção e manejo da HAS, sendo o efeito destas relacionado à composição dos alimentos. Poucos estudos avaliaram o papel dos micronutrientes na pressão arterial (PA) de pacientes com DM e as recomendações atuais de consumo são baseadas em estudos populacionais ou em pacientes sem DM. O objetivo deste manuscrito foi revisar os efeitos da ingestão de micronutrientes consumidos sob a forma de alimentos ou suplementação sobre a PA de pacientes com DM. Foi realizada uma revisão sistemática de ensaios clínicos randomizados (ECR) nas bases Medline e Lilacs. Foram incluídos ECRs realizados em pacientes adultos com DM que avaliaram o efeito de micronutrientes da dieta ou suplementos sobre a PA e com no mínimo duas semanas de intervenções. Foram excluídos ECRs com intervenção múltipla de micronutrientes ou outras (fármacos, exercício). Os dados foram extraídos por dois pesquisadores independentes. Dos 607 estudos inicialmente selecionados foram excluídos 555 com base no título ou resumo; 52 estudos potencialmente relevantes para inclusão tiveram então seu texto completo avaliado e destes, 12 ECR foram incluídos, totalizando 16 intervenções. Em conclusão, a restrição de sódio, a suplementação de magnésio e a suplementação de vitamina D nos pacientes com hipovitaminose D podem conferir melhora nos valores da PA de pacientes com DM. Já o possível efeito benéfico da vitamina C permanece incerto e a administração de vitamina E não é recomendada. A indicação de aumento da ingestão de potássio não foi testada em pacientes com DM. Novos estudos para confirmar e esclarecer o papel destes e de outros micronutrientes sobre a PA de pacientes com DM são necessários. / Hypertension is a multifactorial clinical condition that affects a significant part of the world population, with a higher prevalence in patients with diabetes mellitus (DM) than in the general population. Changes in lifestyle, including dietary intervention, are important tools for prevention and management of hypertension, this effect being related to food composition. Few studies evaluated the role of micronutrients in blood pressure (BP) in patients with DM and the current recommendations were based on population studies in patients without DM. The aim of this study was to review the effects of micronutrients from diet or supplements on BP in patients with DM. A systematic review of randomized controlled trials (RCT) was performed in Medline and Lilacs. It was conducted in adult patients with diabetes and evaluated the effect of micronutrients from diet or supplements on BP after at least two weeks of intervention, RCT trials with multiple micronutrient intervention or other (drugs, exercise) were excluded. Data were extracted by two independent researchers to record changes in BP at the end of the studies. Of the 607 studies initially selected 555 were excluded based on title or abstract; 52 potentially relevant studies for inclusion were then evaluated with their complete text and, from these, 12 RCTs were included, with a total of 16 interventions. In conclusion, sodium restriction, magnesium and vitamin D supplementation in patients with hypovitaminosis D may improve BP values of diabetic patients. However, the possible beneficial effect of vitamin C remains uncertain and the administration of vitamin E is not recommended. The indication of increased potassium intake has not been tested in patients with DM. Further studies are needed to confirm and clarify the role of these and other micronutrients in BP in patients with DM.

A hipertensão arterial sistêmica (HAS) é uma condição clínica multifatorial que acomete parte significativa da população mundial sendo sua prevalência no diabetes melito (DM) mais elevada do que na população em geral. Modificações no estilo de vida, entre elas intervenções dietoterápicas são importantes ferramentas para a prevenção e manejo da HAS, sendo o efeito destas relacionado à composição dos alimentos. Poucos estudos avaliaram o papel dos micronutrientes na pressão arterial (PA) de pacientes com DM e as recomendações atuais de consumo são baseadas em estudos populacionais ou em pacientes sem DM. O objetivo deste manuscrito foi revisar os efeitos da ingestão de micronutrientes consumidos sob a forma de alimentos ou suplementação sobre a PA de pacientes com DM. Foi realizada uma revisão sistemática de ensaios clínicos randomizados (ECR) nas bases Medline e Lilacs. Foram incluídos ECRs realizados em pacientes adultos com DM que avaliaram o efeito de micronutrientes da dieta ou suplementos sobre a PA e com no mínimo duas semanas de intervenções. Foram excluídos ECRs com intervenção múltipla de micronutrientes ou outras (fármacos, exercício). Os dados foram extraídos por dois pesquisadores independentes. Dos 607 estudos inicialmente selecionados foram excluídos 555 com base no título ou resumo; 52 estudos potencialmente relevantes para inclusão tiveram então seu texto completo avaliado e destes, 12 ECR foram incluídos, totalizando 16 intervenções. Em conclusão, a restrição de sódio, a suplementação de magnésio e a suplementação de vitamina D nos pacientes com hipovitaminose D podem conferir melhora nos valores da PA de pacientes com DM. Já o possível efeito benéfico da vitamina C permanece incerto e a administração de vitamina E não é recomendada. A indicação de aumento da ingestão de potássio não foi testada em pacientes com DM. Novos estudos para confirmar e esclarecer o papel destes e de outros micronutrientes sobre a PA de pacientes com DM são necessários. / Hypertension is a multifactorial clinical condition that affects a significant part of the world population, with a higher prevalence in patients with diabetes mellitus (DM) than in the general population. Changes in lifestyle, including dietary intervention, are important tools for prevention and management of hypertension, this effect being related to food composition. Few studies evaluated the role of micronutrients in blood pressure (BP) in patients with DM and the current recommendations were based on population studies in patients without DM. The aim of this study was to review the effects of micronutrients from diet or supplements on BP in patients with DM. A systematic review of randomized controlled trials (RCT) was performed in Medline and Lilacs. It was conducted in adult patients with diabetes and evaluated the effect of micronutrients from diet or supplements on BP after at least two weeks of intervention, RCT trials with multiple micronutrient intervention or other (drugs, exercise) were excluded. Data were extracted by two independent researchers to record changes in BP at the end of the studies. Of the 607 studies initially selected 555 were excluded based on title or abstract; 52 potentially relevant studies for inclusion were then evaluated with their complete text and, from these, 12 RCTs were included, with a total of 16 interventions. In conclusion, sodium restriction, magnesium and vitamin D supplementation in patients with hypovitaminosis D may improve BP values of diabetic patients. However, the possible beneficial effect of vitamin C remains uncertain and the administration of vitamin E is not recommended. The indication of increased potassium intake has not been tested in patients with DM. Further studies are needed to confirm and clarify the role of these and other micronutrients in BP in patients with DM.

Master of Science / Department of Kinesiology / Steven W. Copp / Mechanical signals within contracting skeletal muscles contribute to the generation of the exercise pressor reflex; an important autonomic and cardiovascular control mechanism. In decerebrate rats, GsMTx4, a mechanically–activated channel inhibitor that is partially selective for piezo channels, was found recently to reduce the pressor response during static hindlimb muscle stretch; a maneuver used to investigate the mechanical component of the exercise pressor reflex (i.e., the mechanoreflex). However, the effect was found only during the very initial phase of the stretch when muscle length was changing which may have reflected the inhibition of rapidly-deactivating piezo 2 channels and the fact that different mechanically-activated channels with slower deactivation kinetics evoked the pressor response during the static phase of the maneuver. We tested the hypothesis that in decerebrate, unanesthetized rats, GsMTx4 would reduce the pressor response throughout the duration of a 30 second, 1 Hz dynamic hindlimb muscle stretch protocol. We found that the injection of 10 µg of GsMTx4 into the arterial supply of a hindlimb reduced the peak pressor response (control: 15±4, GsMTx4: 5±2 mmHg, p<0.05, n=8) and the pressor response at multiple time points throughout the duration of the stretch. GsMTx4, however, had no effect on the pressor response to the hindlimb arterial injection of lactic acid. Moreover, the injection of GsMTx4 into the jugular vein (a systemic control, n=5) or the injection of saline into the hindlimb arterial supply (a vehicle control, n=4) had no effect on the pressor response during dynamic stretch. We conclude that GsMTx4 reduced the pressor response throughout the duration of a 1 Hz dynamic stretch protocol which may have reflected the inhibition of piezo 2 channels throughout the dynamic stretch maneuver.

Smart watches in future will have smart wristband. This work analyses properties of new developed capacitive wristband sensor that measures ballistocardiogram (BCG) from single point on the wrist. In addition, it considers applications of this sensor to monitoring heart rate variability. Another application is in estimating changes (trend) in systolic blood pressure continuously when combined with lead one electrocardiogram (ECG). BP is one of the vital signs that indicates the health condition. It is commonly measured by cuff-based monitor using either auscultatory or oscillometric method. Cuff-based BP monitor is not portable and unable to measure BP continuously which means it is difficult to attach BP monitoring function on a wearable device. Significant research is conducted in estimating BP from pulse transit time (PTT) mathematically which would enable the cuffless BP measurement. In this work, a new time reference, RJ interval, which is the time delay between ECG and BCG signal peaks was tested whether it can be used as a surrogate of PTT in cuffless BP estimation. Based on the study done on 10 healthy people, it was shown that RJ intervals can be useful in evaluating trends of systolic blood pressure.

Master of Science / Department of Kinesiology / Steven Copp / Mechanical and metabolic signals arising during skeletal muscle contraction reflexly increase sympathetic nerve activity and blood pressure (i.e., the exercise pressor reflex). In a rat model of simulated peripheral artery disease (PAD) in which a femoral artery is chronically (~72 hours) ligated, the mechanically-sensitive component of the exercise pressor reflex during 1 Hz dynamic contraction is exaggerated compared to that found in normal rats. Whether this is due to an enhanced acute sensitization of mechanoreceptors by metabolites produced during contraction or involves a chronic sensitization of mechanoreceptors is unknown. To investigate this issue, in decerebrate, unanesthetized rats we tested the hypothesis that the increases in mean arterial blood pressure (MAP) and renal sympathetic nerve activity (RSNA) during 1 Hz dynamic stretch are larger when evoked from a previously “ligated” hindlimb compared to those evoked from the contralateral “freely perfused” hindlimb. Dynamic stretch provided a mechanical stimulus in the absence of contraction-induced metabolite production that replicated closely the pattern of the mechanical stimulus present during dynamic contraction. We found that the increases in MAP (freely perfused: 14±1, ligated: 23±3 mmHg, p=0.02) and RSNA were significantly greater during dynamic stretch of the ligated hindlimb compared to the increases during dynamic stretch of the freely perfused hindlimb. These findings suggest that the exaggerated mechanically-sensitive component of the exercise pressor reflex found during dynamic muscle contraction in this rat model of simulated PAD involves a chronic sensitizing effect of ligation on muscle mechanoreceptors and cannot be attributed solely to acute contraction-induced metabolite sensitization.

Nos últimos 15 anos, o uso do propofol vem se popularizando na prática clínica como anestésico intravenoso para indução e manutenção da anestesia em cães e gatos. O objetivo deste estudo foi avaliar os efeitos do propofol na pressão arterial, freqüência e ritmo cardíacos, quando empregado na indução e na manutenção anestésica de cães, verificar a correlação entre os valores de freqüência cardíaca e pressão arterial média, obtidos durante a indução e a manutenção anestésica e avaliar a incidência de efeitos colaterais deste fármaco. Foram utilizados 53 cães, 15 machos e 38 fêmeas, clinicamente sadios, com idades entre 1 e 12 anos, peso entre 2 e 44 kg, de diferentes raças, categoria de risco ASA 1 ? 2. Após avaliação clinica, foi administrada a medicação pré-anestésica (T0) constituída de acepromazina (0,05mg/kg) e meperidina (3mg/kg) pela via intramuscular. A indução da anestesia foi realizada em dois momentos, no primeiro momento infundiu-se metade da dose de propofol calculada (T1), no segundo momento procedeu-se o término da administração da dose total de indução da anestesia (T2), o terceiro momento correspondeu a intubação orotraqueal (T3). Durante a manutenção da anestesia, avaliou-se os momentos após 5 minutos de manutenção (T4), 10 minutos (T5) e 20 minutos (T6), onde o grupo 1 recebeu o agente inalatório isofluorano em O2 a 100% e o grupo 2 infusão contínua de propofol na dose de 0,6mg/kg/min e O2 a 100%, ambos os grupos permanecendo em plano anestésico adequado. Pode-se observar que a freqüência cardíaca foi, em média, superior durante o período de indução anestésica e a pressão arterial média foi, em média inferior, porém, clinicamente, a magnitude destas alterações pode ser considerada de pouca importância clínica. Não existiu correlação estatisticamente significante entre a queda da pressão arterial média e o aumento da freqüência cardíaca em nenhum dos tempos analisados, o que leva a crer que o aumento da freqüência cardíaca se deve provavelmente à diminuição da atividade parassimpática neural cardíaca e prevalência da atividade simpática cardíaca, e a diminuição da pressão arterial encontrada pode ser secundária à diminuição da atividade simpática periferia. A avaliar o ritmo cardíaco notou-se diminuição da incidência de bradiarritmias e arritmia sinusal e um aumento do ritmo sinusal, provavelmente pela diminuição da atividade parassinpática cardíaca. Tais observações sustentam a hipótese de que o propofol pode agir diferentemente na atividade simpática periférica e cardíaca também nos cães. Pode-se ainda levantar a hipótese de que a atividade barorreflexa também pode estar diminuída nos cães já que não houve correlação significante entre a diminuição da pressão arterial e o aumento subseqüente da freqüência cardíaca. Durante a manutenção da anestesia houve uma queda da pressão arterial, sem importância clinica e não houve alteração significante em relação a freqüência cardíaca. Foi possível observar excitação em apenas dois animais no momento T1 e um animal em T2. Apnéia foi observada em apenas oito animais (15,1%) sete no momento T3. Outros trabalhos utilizando-se medidas da atividade barorreceptora, análise espectral da variabilidade da freqüência cardíaca, neuromicrografia ou até mesmo medida do clearence de norepinefrina para melhor avaliação da atividade simpática de cães durante a anestesia ainda devem ser realizados para comprovação destas hipóteses fortemente sugestivas pelos dados encontrados neste estudo. O propofol demonstrou ser um fármaco seguro quando empregado na indução e na manutenção da anestesia em cães, não causando alterações cardiovasculares clinicamente importantes. / In the last 15 years, using propofol has being popular in the practical clinic as intravenous anesthetic for induction and maintenance of the anesthesia in dogs and cats. The aim of this study was to evaluate the effect of propofol in arterial pressure, cardiac frequency and rhythm, when used in the induction and in the anesthetical maintenance of dogs, to verify the correlation between values of cardiac frequency and average arterial pressure, taken during the induction and the anesthetical maintenance and to evaluate the incidence of side effects of this drug. Had been used 53 dogs, 15 males and 38 females, clinically healthy, with ages between 1 and 12 years, weight between 2 and 44 kg, from different breeds, ASA classification 1 - 2. After clinical evaluation, the anesthetical drug was administered (T0) consisting of acepromazine (0,05mg/kg) and meperidine (3mg/kg) through intramuscular injection. The induction of the anesthesia was carried through at two moments: at the first moment was administered half of the dose of propofol calculated (T1), at second moment was proceeded the ending of the administration of the total dose of induction of the anesthesia (T2); the third moment corresponded the orotracheal intubation (T3). During the maintenance of the anesthesia, were evaluated the moments after 5 minutes of maintenance (T4), 10 minutes (T5) and 20 minutes (T6), when group 1 received isofluorane inhalatory agent in 100% O2 and group 2 continuous infusion of propofol in the dose of 0,6mg/kg/min and 100% O2, both groups remaining in adequate anaesthetic stage. It can be observed that the cardiac frequency was, in average, superior during anesthetical induction period and the average arterial pressure was often inferior, however, clinically the magnitude of these alterations can be considered of little clinical importance. Statiscally significant correlation did not exist between the fall of the average arterial pressure and the increase of the cardiac frequency in none of the analyzed periods, leading to believe that the increase of the cardiac frequency is must probably due to the reduction of the cardiac parasympathetic neural activity and prevalence of the cardiac sympathetic activity, and the reduction of arterial pressure can be secondary to the reduction of the periphery sympathetic activity. Evaluating the cardiac rhythm noticed reduction of the incidence of low cardiac frequency and sinusal arrhythmia and an increase of the sinusal rhythm, probably due to the reduction of the cardiac parasympathetic activity. Such comments support the hypothesis that propofol can act differently in the peripheral and cardiac sympathetic activity also in dogs. The hypothesis that pressure-induced activity could be also decreased in dogs can be raised, since there was not significant correlation between the reduction of arterial pressure and the subsequent increase of cardiac frequency. During the maintenance of the anesthesia there was a fall of the arterial pressure, of no clinical importance and there was no cardiac frequency significant change. It was possible to observe excitement in only two animals at moment T1 and one animal in T2. Apnea was observed in only eight animals (15.1%) seven at moment T3. Other studies using measurement of the pressure-induced activity, spectral analysis of the variability of cardiac frequency, neuromicrography or even though norepinephrine clearance measurement for better evaluation of the sympathetic activity of dogs during the anesthesia still must be done to prove these strong suggestive hypotheses for the data found in this study. Propofol demonstrated to be a safe drug when used in the induction and the maintenance of the anesthesia in dogs, not causing important cardiovascular clinical changes.