Circulatory and Respiratory Physiology Commons^™

Short Term Hemodynamic Effects Of Atrial Fibrillation In A Closed-Loop Human Cardiac-Baroreflex System, Oluwasanmi Adeodu, Michelle Gee, Babak Mahmoudi, Rajanikanth Vadigepalli, Mayuresh V. Kothare

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

Atrial fibrillation (AF) remains the leading cardiac cause of stroke and AF-related death rate in the United States has been increasing for over twenty years. While the effect of standalone AF on heart rate is well established, there is a lack of clarity on its impact on other critical hemodynamic metrics. This is ostensibly due to interaction with other common comorbidities, especially hypertension. In addition, AF has a complex relationship with the state of the baroreflex. Evidence indicates that baroreflex sensitivity (BRS), the ability of the intrinsic cardiac control system to initiate parasympathetic response, is suppressed during AF. Therefore, a …

Potential Role Of The Large Protein Titin In The Development Of Heart Failure, Mary M. Prickett

Senior Theses

I will be exploring the impact of the large protein Titin on heart failure with a preserved ejection fraction (HFpEF). It was hypothesized that myocardial Titin plays a significant role in the progression of HFpEF through isoform, N2BA and N2B, changes. It was hypothesized that an increase in the quantity of N2B Titin, less compliant, and a decrease in N2BA Titin, more compliant, will be observed as HF progresses, contributing to an increase in passive stiffness involved in heart contraction. I will cover a detailed report on the role of Titin in HFpEF and propose research methods to explore further.

Influence Of Longitudinal Position On The Evolution Of Steady-State Signal In Cardiac Cine Balanced Steady-State Free Precession Imaging, Tyler J. Spear, Tori A. Stromp, Steve W. Leung, Moriel H. Vandsburger

Saha Cardiovascular Research Center Faculty Publications

Background: Emerging quantitative cardiac magnetic resonance imaging (CMRI) techniques use cine balanced steady-state free precession (bSSFP) to measure myocardial signal intensity and probe underlying physiological parameters. This correlation assumes that steady-state is maintained uniformly throughout the heart in space and time.

Purpose: To determine the effects of longitudinal cardiac motion and initial slice position on signal deviation in cine bSSFP imaging by comparing two-dimensional (2D) and three-dimensional (3D) acquisitions.

Material and Methods: Nine healthy volunteers completed cardiac MRI on a 1.5-T scanner. Short axis images were taken at six slice locations using both 2D and 3D cine bSSFP. 3D acquisitions …

Thyroid Hormone As A Method Of Reducing Damage To Donor Hearts After Circulatory Arrest, William P. Adams

Theses and Dissertations

There is a chronic lack of donor hearts to meet the need for heart transplant both in the US and worldwide. Further, the use of available hearts is limited by the short period between collection and implantation during which the heart can be safely preserved ex vivo. Using mid-thermic Langendorff machine perfusion, we have been able to preserve the metabolic function of a healthy heart for up to 8 hours, twice the limit for current static cold storage. We have also been able to preserve the metabolic function of a damaged DCD Heart collected 30 minutes after cardiac arrest …

Role Of Ataxia Telangiectasia Mutated Kinase In The Healing Process Of The Heart Following Myocardial Infarction, Laura L. Daniel

Electronic Theses and Dissertations

Ataxia telangiectasia (AT), caused by mutations in the gene encoding ataxia telangiectasia mutated kinase (ATM), is a rare autosomal recessive disorder. AT individuals exhibit neuronal degeneration and are predisposed to cancer. Carriers of this disorder are predisposed to cancer and ischemic heart disease. Heart disease, mostly due to myocardial infarction (MI), is a leading cause of death in the US. Following MI, release of catecholamines in the heart stimulates β- adrenergic receptors (β-AR). Our lab has shown that β-AR stimulation increases ATM expression in the heart and myocytes, and ATM plays an important role in β-AR-stimulated myocardial remodeling with effects …

Extracellular Ubiquitin: Role In Cardiac Myocyte Apoptosis And Myocardial Remodeling, Christopher Ray Daniels

Electronic Theses and Dissertations

Activation of sympathetic nervous system is a key component of myocardial remodeling that generally occurs following ischemia/reperfusion (I/R) injury and myocardial infarction. It induces cardiac myocyte apoptosis and myocardial fibrosis, leading to myocardial dysfunction. Intracellular ubiquitin (UB) regulates protein turnover by the UB-proteosome pathway. The biological functions of extracellular UB in the heart remain largely unexplored. Previously, our lab has shown that β-adrenergic receptor (β-AR) stimulation increases extracellular UB levels, and extracellular UB inhibits β-AR-stimulated apoptosis in adult rat ventricular myocytes (ARVMs). This study explores the role of extracellular UB in myocyte apoptosis, fibroblast phenotype and function, and myocardial remodeling …

Aging Influences Multiple Indices Of Oxidative Stress In The Heart Of The Fischer 344/Nnia X Brown Norway/Binia Rat, Shinichi Asano

Theses, Dissertations and Capstones

Here we report the influence of aging on multiple markers of oxidativenitrosative stress in the heart of adult (6-month), aged (30-month) and very aged (36- month) Fischer 344/NNiaHSd X Brown Norway/BiNia (F344/NXBN) rats. Compared to 6 month old rat hearts, indices of oxidative (superoxide anion (–O2 ·), 4-hyrdoxy-2- nonenal (4-HNE)) and nitrosative (protein nitrotyrosylation) stress were 34.1 ± 28.1%, 186 ± 28.1% and 94 ± 5.8% higher, respectively, in 36-month hearts and these findings were highly correlated with increases in left ventricular wall thickness (r>0.669; r>0.710 and p<0.01, respectively). Regression analysis showed that increases in cardiac oxidative-nitrosative stress with aging were significantly correlated with changes in the expression and/or regulation of proteins involved in transcriptional (NF-κB) activities, signaling (mitogen activated protein kinases along with Src), apoptotic ( Bcl-2, Traf-2), and cellular stress (HSPs). These results suggest that the aging F344/NXBN heart may be highly suited for unraveling the molecular events that lead to age-associated alterations in cardiac oxidative stress.

Age-Related Dgc Structure And Function In The F344/N X Bn Rat Heart, Sunil K. Kakarla

Theses, Dissertations and Capstones

Recent data has suggested that disruption of the dystrophin-glycoprotein complex (DGC) may be involved in mediating the progression of cardiac hypertrophy and failure. Here we examined the regulation of DGC proteins in the hearts of adult (6 months), aged (30 months), and very aged (36 months) F344/N X BN rats . Compared to adult animals, the content of α- and β-dystroglycan were 6.93 ± 5.16% and 58.36 ± 3.64% higher, respectively (P < 0.05) in very aged animals. Immunoblotting and immunhistochemical analysis suggested that aging appeared to diminish alpha-sarcoglycan, beta-sarcoglycan and delta-sarcoglycan content by 13.89 ± 3.1%,15.8 ± 2.8% and 18.63 ± 3.04%, respectively (P < 0.05). These alterations in the DGC occurred coincident with age- associated alterations in cytoplasmic anti-rat IgG immunoreactivity, TUNEL positive nuclei, alpha-fodrin cleavage, indices of caspase-3 activation and diminished AKT phosphoryation (Ser 308). Taken together, these data suggest that aging alters cardiac DGC structure and function.