Theses and Dissertations from UMD
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New submissions to the thesis/dissertation collections are added automatically as they are received from the Graduate School. Currently, the Graduate School deposits all theses and dissertations from a given semester after the official graduation date. This means that there may be up to a 4 month delay in the appearance of a give thesis/dissertation in DRUM
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Item HIPPOCAMPAL GLUCOSE TRANSPORT AND OXIDATION IN RESPONSE TO DISRUPTED BLOOD FLOW IN AN AGING RAT MODEL OF HEART FAILURE(2023) Pena, Gabriel Santiago; Smith, J. Carson; Kuzmiak-Glancy, Sarah; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The primary objective of this dissertation was to investigate, in a rodent model of cardiovascular disease promoted by transverse aortic constriction (TAC), whether cerebral hypoperfusion stemming from chronic high pulsatile blood flow, and cerebral hypoperfusion stemming from low cerebral blood flow differentially affected hippocampal glucose transport and hippocampal mitochondrial function. We first, characterized the changes in right and left carotid hemodynamics and diameter in response to TAC and in a SHAM control group at three different time points (20-, 30-, and 40 weeks) post-surgery. Then, right, and left hippocampal mitochondrial content and substrate oxidation were investigated, and protein expression of glucose transporters and mitochondrial quality control markers were quantified. In this study, both the SHAM and TAC conditions included male and female rats to address possible sex differences. We report that all time points within TAC, right carotid blood flow velocities and pulsatility were greater than the left, but did not worsen over time. No differences in mitochondrial content were found within TAC nor between TAC and SHAM, but within TAC animals there were impairments in right hippocampal coupled and uncoupled respiration when compared to the left. When compared to the SHAM controls, right and left hippocampi of TAC animals had higher protein expression of mitochondrial quality control markers, but no differences in glucose transporter expression were found. Thus, while both high blood flow and/or pulsatility as well as low cerebral blood flow may lead to brain hypoperfusion, the metabolic consequences of the two may not be the same. The results from this dissertation contribute to the expanding literature characterizing the intersection between cardiovascular disease and neurodegeneration.Item SIMILAR VASCULAR RESPONSES TO A HIGH-FAT MEAL, REGARDLESS OF RACE AND SOCIAL DETERMINANTS OF HEALTH(2022) Weiner, Cynthia Marie; Ranadive, Sushant M; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Black individuals are at a higher risk for developing cardiovascular disease (CVD), including hypertension, compared to white individuals. Chronic low-grade inflammation contributes to hypertension by causing vascular dysfunction, including increased vascular resistance. Young, healthy, normotensive black individuals exhibit heightened inflammatory biomarkers at rest, a possible factor in the higher prevalence of hypertension seen within this population. Vascular function decreases transiently as a result of an acute inflammatory stimulus, such as with consumption of a high-fat meal (HFM). However, there is limited evidence regarding the racial differences in inflammatory and vascular responses to a HFM in young, healthy black and white individuals. Furthermore, there are limited data regarding the association between social determinants of health (SDH) factors and the physiological components of inflammation and vascular responses. Therefore, the goal of the present study was twofold: to evaluate the racial differences in inflammatory and vascular responses to a HFM and to evaluate the potential impact of SDH factors on these relationships. Five black individuals (5 males, 21.2 ± 1.5 yrs) and 14 white individuals (7 males/7 females, 25 ± 4.1 yrs) completed the study. White individuals were significantly older than black individuals, but were similar in fitness status (VO2peak; 43.4 ± 10.8 ml/kg/min vs. 40.5 ± 5.9 ml/kg/min) and BMI (22.6 ± 2.9 kg/m2 vs. 23.5 ± 3.3 kg/m2). Black and white individuals exhibited similar vascular function, arterial stiffness, wave reflection, and hemodynamic variables (BP, HR) at baseline and following the HFM. Black individuals had a significantly lower total SDH score compared to white individuals, indicating lower SDH across seven domains assessed in the SDH questionnaire. However, SDH was not associated with any of the vascular measurements at baseline or following the HFM. Inflammation was not detected at baseline and following the HFM, as measured by a multiplex immunoassay. Therefore young, healthy black and white individuals maintain vascular function following a HFM, regardless of SDH status.Item INVESTIGATING CARDIOVASCULAR RISK AT THE INTERSECTION OF RACE, GENDER, AND EDUCATION(2019) Taiwo, Omolola Tanya; Boekeloo, Bradley O; Public and Community Health; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)As a risk factor of cardiovascular disease (CVD), systemic inflammation is differentially distributed by race, with black populations disproportionately impacted. Additionally, inflammation, as measured by the inflammatory marker C-reactive protein (CRP), is documented to be higher among women when compared to men and varies by educational level. Despite evidence suggesting that various chronic stress domains may contribute to the relationship between race and inflammation, there is limited data exploring the possible mediating role of chronic stress. Furthermore, to date, no study has examined if the potential indirect effect of race on CRP through chronic stress domains are moderated by gender and education. This secondary data analysis stems from the Midlife Development in the United States (MIDUS II) study, and the sample consisted of 193 black and 582 white adults. Study 1: Examined the association between CRP and seven racial/gender/education subgroups. With educated white men as the reference group, findings revealed that educated black and white women had the highest significant risk for elevated CRP. Study 2: Assessed the psychometric properties of a Chronic Stress Scale (CSS) comprised of nine chronic stress subscales. Analyses revealed CSS to be a three-dimensional scale with questionable validity and reliability. Study 3: First, tested for significant correlations between nine chronic stress domains, race, and CRP. Everyday discrimination and financial strain were found to be the only two domains significantly correlated to race and CRP. Second, two mediation analyses assessed the mediating effect of financial strain and discrimination, finding that they both respectively mediated the relationship between race and CRP. Third, two moderated mediation analyses examined if the indirect effect of financial strain and discrimination were moderated by gender and education. Results indicated that the indirect effect of race on CRP through discrimination was significant only among educated black men. Additionally, findings revealed that the indirect effect of race on CRP through financial strain was significant among black men and women regardless of educational attainment. Combined, these studies characterized the social patterning of CRP, illustrated validity and reliability concerns when developing a multidimensional chronic stress scale, and revealed that discrimination and financial strain did have mediating roles and these mediators were moderated by gender and education.Item Exercise training-associated differences in circulating microRNAs and serum-induced endothelial cell migration rate(2015) Sapp, Ryan M.; Hagberg, James M; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Cardiovascular Diseases (CVDs) are the primary source of global mortality and morbidity. The initial steps of CVD development occur in the endothelium. MicroRNAs (miRNAs) have recently emerged as novel regulators of cardiovascular physiology and pathology. Interestingly, regular aerobic exercise acts to prevent CVDs and also regulates miRNAs in the circulation (ci-miRNAs). The purpose of this study was to determine the effects of serum from highly active and sedentary, young, healthy individuals on migration rate of endothelial cells in vitro. Secondarily, CVD-associated ci-miRNAs in serum were compared between groups. The results of this study represent a novel way by which sedentary behavior may act as an early risk for CVD development before the appearance of other classic risk factors. RT-qPCR array analysis identified nine ci-miRNAs as > 4-fold differentially expressed in serum of trained versus inactive subjects, though more subjects are needed before any conclusions about ci-miRNA differences can be made.Item Dietary and Acculturation Factors Influencing Metabolic Syndrome among South Asian Americans In Two Community Health Centers in Maryland(2014) Khan, Saira; Jackson, Robert; Nutrition; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)South Asian's (SA) have been observed to have higher insulin resistance followed by an altered state of metabolism; however, few studies have attempted to explore the acculturation process and dietary practices of immigrant SA's in the U.S. 1401 South Asian Americans living in Maryland from India, Pakistan, Bangladesh, Sri Lanka, Nepal, Iran, and Afghanistan were selected from two community health clinics to determine the prevalence of metabolic syndrome (MetS) in this study group and its indicators. The prevalence of MetS (51%) in adults was higher than African Americans, European Americans, and Mexican Americans. Overall, Indians had the highest percent of MetS 54% compared to Bengali 51%, Pakistani 49%, or Other SA 44%. The results suggest the high prevalence of MetS among SA may be due to a lack of acculturation in this survey group where 80% were classified as Asian low acculturated. Results from a logistic regression analysis showed that the likelihood of developing MetS was high, but future investigations are needed to confirm the role of acculturation from a more representative sample of SA's. We also examined the role of acculturation, diet and exercise in South Asians who acquire MetS. We also examined the diet quality using the 2010 guidelines. The low acculturated South Asians had a greater prevalence of MetS and the overall diet quality of the low income South Asians in Maryland needed improvement. The SA male and female mean scores for the healthy eating index-2010 were 71.9 ± 1.9 and 67.9 ± 1.2, respectively. Males were more acculturated, consumed healthier foods, and had a lower percent of MetS compared to females.Item IS THE CURRENT DEFINITION OF THE METABOLIC SYNDROME A USEFUL TOOL FOR THE DETECTION OF CARDIOVASCULAR DISEASE IN NON-HISPANIC BLACKS?(2010) Rodriguez, Omayra Isabel; Song, Jiuzhou; Nutrition; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Blacks in the country suffer from higher prevalences of obesity, diabetes, hypertension and cardiovascular disease compared to whites. Paradoxically, they have the lowest prevalence of the Metabolic Syndrome (MS) compared to whites and Mexican Americans. This is likely due to the fact that blacks tend to have lower triglycerides (TG) and higher high density cholesterol (HDL) levels. We challenged the current lipid criteria established by the Adult Treatment Panel III for the detection of the MS and set out to find more appropriate TG and HDL cutoffs to detect the MS in blacks. Using data from the National Health and Nutrition Examination Survey from 1999-2006, we identified that a more appropriate TG cutoff for blacks to detect the MS is 110 mg/dL but were not able to identify more suitable HDL cutoffs. Our results confirm that race/ethnic-specific criteria should be established for the detection of the MS across racial/ethnic groups.