Life Sciences Commons^™

Dexterous Manipulation Capabilities Are Associated With Change In Discharge Rate Properties Of Motor Neurons With Age, Mukta N. Joshi

Theses and Dissertations

Aging is accompanied by declines in manual dexterity and fine motor control. The purpose of this research was to compare hand motor control in young and older adults and examine the neuromuscular mechanisms responsible for enabling these interactions. We test force variability during isometric and dynamic contractions, manual dexterity and track motor unit activity to identify the neuromuscular mechanisms responsible for changes in dexterity with age. 26 older adults (66-86 years) and 28 young adults (19 – 38 years) participated in the study. Research participants performed force matching tasks during index finger abduction, precision pinch, static pressing and hybrid force/ …

Effects Of Parkinson’S Disease On Motor Asymmetry, Deborah Mazanek Watson

Theses and Dissertations

Introduction: Persons with Parkinson’s disease (PD) experience changes cortically, subcortically and behaviorally. This dissertation examines the asymmetry of motor behavior to explore the role of asymmetry in persons with PD and its connection to clinical symptoms. Purpose: Project 1: To assess the hand asymmetry difference in young adults versus older adults. Project 2: To investigate the difference in hand asymmetry in older adults and persons with PD. Project 3: To explore the correlation between function and clinical symptoms of persons with PD. Methods: 55 right-handed participants [Young Adults (YA) = 20, Female = 10; Older Adults (OA) = 20, Female …

Are Changes In Muscle Blood Flow Associated With The Age-Related Decrease In Critical Power?, Abigail Dorff

Theses and Dissertations

Aging results in lower exercise tolerance, manifested as decreased Critical Power (PCRIT). Aging is also associated with reduced physical activity, decreased muscle mass, and altered muscle blood flow, all of which may contribute to the age-related decrease in PCRIT. Purpose: The purpose of this study was to determine if the age-related decrease in PCRIT occurs independently of changes in physical activity and muscle mass and if it is related to impaired muscle blood flow. Methods: 10 Old (63.1 ± 2.5 years, 5 female and 5 male) and 10 Young (24.4 ± 4.0 years, 5 female and 5 male) physically active …

Physiological Roles Of Selenoprotein H In Mice, Qingzhou Wang

Theses and Dissertations

Low-hierarchy selenoproteins are sensitive to selenium (Se) deficiency and are proposed to confer the protection of body Se against age- and development-related diseases. Selenoprotein H (SELENOH), a low-hierarchy selenoprotein, is greatly downregulated by both dietary Se deficiency and age. To explore physiological roles of SELENOH, Selenoh knockout mice were employed.

Segregation analyses demonstrated reduced frequencies of homozygotes and heterozygotes among the neonates of the breeding combinations of Selenoh^+/- males vs. Selenoh^+/- or Selenoh^-/- females, demonstrating essential roles of SELENOH in embryogenesis. Litter sizes from these two breeding groups were comparable with control, suggesting a role of SELENOH …

Characterization Of Biomarkers For Alzheimer’S Disease And Hiv-1 Associated Neurocognitive Disorders, Armando Garces Iii

Theses and Dissertations

Alzheimer’s disease is a neurodegenerative disorder that is characterized by progressive cognitive decline and the accumulation of amyloid beta and neurofibrillary tangles in regions of the brain. These protein deposits are known to generate multiple effects on the brain that lead to neurodegeneration. It has been established that (Human Immunodeficiency Virus) HIV-1 accelerates the aging process of people living with HIV-1. Moreover, there is significant clinical evidence indicating a potential link between the neurodegeneration developed by those with an HIV-1 infection and AD. HIV-1 viral infection causes cognitive impairment known as …

Eye Movements And Attention Are Related To Impaired Hand Motor Control In Older Adults, Brittany Heintz Walters

Theses and Dissertations

Visual information is critical for many goal-directed movements and changes in visual information influence hand motor performance in older adults. Knowledge of eye movements during hand motor tasks would provide greater insight into impaired hand function in older adults. This dissertation examined age-related changes in eye movements and the association with hand motor impairments in older adults. Given that attention plays a role in motor performance and declines with age, the relationship between attentional processes and hand motor control was also assessed. A total of 23 young (age 20 – 38) and 28 older (age 65 – 90) adults were …

Investigating The Regulation And Role Of P38 Mapk In Collagen-Related Limb Girdle Muscular Dystrophy, Briseida Oceguera-Perez

Theses and Dissertations

Aging is an expected and normal process across living organisms. It is characterized as a loss of stress resistance, degeneration of tissues, and decline in motor function that happen gradually across lifespan. Susceptibility to neurodegenerative and dystrophic conditions also increase, and unlike aging, are not a normal aspect of lifespan. Discerning the difference between normal and aberrant aging states will give insight into the mechanisms behind the progressive dysfunction shared among organisms. Previous work in our lab has shown that the aging gene p38 MAPK in Drosophila melanogaster plays a significant role in the aging process through its downstream effects …

Epigenetic Regulation Of Drug Metabolizing Enzymes In Normal Aging, Mohamad M. Kronfol

Theses and Dissertations

Geriatric populations are at a higher risk for adverse drug reactions (ADRs). This may be partly due to changes in drug metabolism in old age, but the underlying mechanisms are poorly understood. Prior research in humans and mice has shown age-associated changes to the expression of several genes involved in drug metabolism. Furthermore, studies of human blood showed that epigenetic regulation of genes encoding drug metabolizing enzymes change with age. However, it is unknown if genes in the liver are similarly affected. Therefore, we hypothesize that genes encoding drug metabolizing enzymes may show differential epigenetic regulation in the liver with …

Memory-Based Viewing: A Potential Marker Of Pathological Aging, Jenna Blujus

Theses and Dissertations

Markers of cognitive impairment are needed to distinguish normal from pathological aging prior to the onset of clinical symptomology to improve Alzheimer’s disease (AD) treatment or prevention efforts. AD pathology is believed to develop years or even decades prior to diagnosis in medial temporal lobe subregions that provide input to the hippocampus (Braak & Braak, 1991), disrupting the ability of the hippocampus to bind individual elements of an experience to form cohesive memory representations. Eye movement behavior is a sensitive index of learning and effects of memory on eye movements have been shown to emerge rapidly (within 500-750ms of stimuli …

Memory-Based Viewing: A Potential Marker Of Pathological Aging, Jenna Blujus

Theses and Dissertations

Markers of cognitive impairment are needed to distinguish normal from pathological aging prior to the onset of clinical symptomology to improve Alzheimer’s disease (AD) treatment or prevention efforts. AD pathology is believed to develop years or even decades prior to diagnosis in medial temporal lobe subregions that provide input to the hippocampus (Braak & Braak, 1991), disrupting the ability of the hippocampus to bind individual elements of an experience to form cohesive memory representations. Eye movement behavior is a sensitive index of learning and effects of memory on eye movements have been shown to emerge rapidly (within 500-750ms of stimuli …

Replacing Sedentary Behavior With A Light Intensity Physical Activity In The Homes Of Older Adults, Nicholas Louis Lerma

Theses and Dissertations

Aging is positively correlated with time spent in sedentary behavior (SB), which has been found to be linked to premature mortality, cardiovascular disease risk, and functional limitations. Moderate-to-vigorous-intensity physical activity (MVPA) is a potent stimulus for preventing and improving functional limitations in older adults, but less than 17% of the older adult population meets the recommended PA guidelines. While increased time spent in SB is detrimental to health in all, the impact among those that are physically inactive appear to be most pronounced. Recent evidence suggests increasing light-intensity physical activity (LPA) in these populations may provide health benefits and could …

Determining The Relationship Between Aging And Oxidative Stress In A Drosophila Melanogaster P38 Kb Framework, Aleksandra J. Majewski

Theses and Dissertations

Aging is inevitable for all organisms and can be characterized by degeneration of tissue, adecrease in motor function, and impaired stress response. In humans, it is often accompanied by an increased propensity for age related diseases. While all adults experience biological aging (senescence) not all adults experience age-associated disease. Thus, we claim these are not normal prospects of aging. Although the implications of aging are well understood, the molecular underpinnings for these processes remain elusive. As advances in medical science have been successful at prolonging lifespan, they concurrently extend the amount of time spend in diseased states. If we wish …

Rescuing Age-Related Proteolysis Deficits With Methylene Blue, Shane E. Pullins

Theses and Dissertations

The average lifespan is constantly increasing with the advent of new medical techniques, and age-related cognitive decline is becoming a prevalent societal issue. Even during healthy aging, humans and rats exhibit progressive deficits in episodic/declarative memory. In laboratory rats, age-related memory impairment can be assessed with trace fear conditioning (TFC). Recent research implicates ubiquitin proteasome system-mediated protein degradation in the synaptic plasticity supporting memory formation and retrieval. In rats, aging leads to decreased basal proteolytic activity in brain structures known to support the acquisition and retrieval of trace fear memories, and our preliminary data suggests activity-dependent proteasome activity declines in …

Influence Of Expectations Of Aging On Older Women’S Use Of Dietary Supplements Using The Health Promotion Theory, Barbara Emily Hekel

Theses and Dissertations

The use of vitamins, minerals and herbal supplements by older adults is increasing and changing. There are concerns about supplement quality, safety, and vitamin D overuse. Little is known about supplement use by nursing home residents and about factors that influence older women to use supplements. The current study describes the supplement use of 247 nursing home residents and 110 independent living women 65 years or older in the Midwestern United States. A secondary analysis of 247 medication administration records describes the prevalence of vitamin, mineral, and herbal supplement use of nursing home residents. Using the health promotion theory, the …

Comparisons Of Isogenic Trisomic And Disomic Cells From People With Mosaicism For Down Syndrome Unmask Cellular Differences Related To Trisomy 21, Kelly A. Rafferty

Theses and Dissertations

It is known that age-related changes impacting multiple organ systems occur earlier in people with Down syndrome (Ds), but the biological basis underlying this trisomy 21-associated propensity for premature aging is poorly understood. Given that the trisomic/normal cells from people with mosaic Ds (mDs) are identical with regards to environmental exposures and genes (except for chromosome 21 copy number), comparisons of these isogenic trisomic/disomic cells allow one to “unmask” the cellular consequences of trisomy 21 by removing extraneous factors. The primary aim of this study was to determine if trisomy 21 results in an increase in the acquisition of age-related …

Apoaequorin Differentially Modulates Fear Conditioning In Adult And Aged Rats, Vanessa Ehlers

Theses and Dissertations

Normal aging is associated with a number of changes in behavioral and cellular function, and is often linked to increased susceptibility to cognitive impairment. The hippocampus has been widely implicated in learning and memory, and many forms of learning that are hippocampus-dependent (e.g. trace fear conditioning) are impaired in aged animals. A proposed contributor to aging-related cognitive impairment is aging-related calcium (Ca2+) dysregulation. This dysregulation is thought to result from changes in specific Ca2+-regulatory mechanisms, including abnormal Ca2+ ion channel activity or expression, as well as reduced Ca2+-binding protein (CaBP) expression, which is associated with cognitive and synaptic impairment. Previous …

Investigation Of Neural Mechanisms Of Grip Relaxation, Binal Motawar

Theses and Dissertations

Neural mechanisms for grip relaxation are relatively unknown and understudied, as compared to mechanisms for grip initiation. Yet, termination of motor activity is as important as initiation in daily function. This knowledge gap presents incomplete understanding of neural control of hand function and its impairment with aging and neurologic disorders. The purpose of this dissertation was to identify and examine neural mechanisms of grip relaxation in healthy young adults, with aging, and in chronic stroke survivors. A series of experiments in healthy young adults showed that the relaxation from a maximum power grip was mediated by increase in the short-interval …

Establishing The Microcrustacean Daphnia As A Model System For Research On Aging, Charles Andrew Shumpert

Theses and Dissertations

Aging is a ubiquitous process pertaining to all biological systems around the planet. Although much has been learned from studies so far on the molecular mechanisms that lead to aging, a complete understanding of a healthy life span and longevity still eludes us. In this dissertation, we will examine the use of a freshwater microcrustacean Daphnia as a model system for studies on the biology of aging. The Introduction chapter presents a review of the general molecular alterations associated with cellular and organismal aging, and discusses the core model organisms currently used to study the aging process. The introduction chapter …

Individual, Occupational And Biomechanical Factors That Affect Slip And Fall Risk From Fixed Ladders, Erika Mae Pliner

Theses and Dissertations

Injuries from ladder falls are prevalent and severe. Previous research has examined certain elements of ladder falls such as the ladder base slipping, but few studies have examined the factors that contribute to climbers falling from the ladder, particularly for permanent/fixed ladders. In addition, the biomechanical response to a ladder slip/misstep during ladder climbing and the factors that affect a fall from a ladder are not well understood. This thesis is a two part study that simulated ladder slips and missteps in order to find factors 1) associated with ladder slip risk and 2) that decrease fall severity from a …

Working Together: Using Protein Networks Of Bacterial Species To Compare Essentiality, Centrality, And Conservation In Escherichia Coli., Christopher Wimble

Theses and Dissertations

Proteins in Escherichia coli were compared in terms of essentiality, centrality, and conservation. The hypotheses of this study are: for proteins in Escherichia coli, (1) there is a positive, measureable correlation between protein conservation and essentiality, (2) there is a positive relationship between conservation and degree centrality, and (3) essentiality and centrality also have a positive correlation. The third hypothesis was supported by a moderate correlation, the first with a weak correlation, and the second hypotheis was not supported. When proteins that did not map to orthologous groups and proteins that had no interactions were removed, the relationship between essentality …

The Effects Of Exercise Training On Cognitive Reserve And Cognitive Function In Healthy Older Women, Katie Marie Becofsky

Theses and Dissertations

Cognitive reserve theory suggests that physical activity may protect individuals from cognitive decline. At the brain level, greater cognitive reserve may manifest as greater neural network efficiency. Our purpose was to investigate 1) whether participation in a 16-week walking program increased brain efficiency, and 2) whether increased brain efficiency correlated with change in fitness and task performance. Our secondary purpose was to investigate whether exercise training improved performance on a battery of cognitive tasks, particularly executive functioning performance. Seventeen healthy but sedentary women aged 60-75 years participated in a supervised walking program; eighteen women served as a non-randomized control group. …

The Effects Of Arthritis Foundation’S “Walk With Ease” Program On Cognitive Function, Ryan S. Falck

Theses and Dissertations

Physical activity (PA) is believed to improve cognitive function, particularly executive function, in older adults. However, few interventions in community settings have been performed to improve executive function through PA. The purpose of this study was to determine the effects of a community-based walking program on executive function in older adults (60+ years). Older adults from senior centers throughout Lexington County, SC were recruited for participation in this intervention. Exclusion criteria included currently exercising >30 minutes and exercising ≥2x/week or scoring ≤25 on the Mini-Mental State Exam. The intervention consisted of an evidenced-based community walking program, the Arthritis Foundation ’ …

The Effects Of Aging On Skeletal Muscle Ampk Activation And An Analysis Of Chronic Aicar Treatment On The Aging Phenotype, Shalene E. Hardman

Theses and Dissertations

AMP-activated protein kinase (AMPK), a metabolic regulator, acts in opposition to many of the effects of aging and may provide insights into the development of sarcopenia. However, the effect of aging on AMPK activation is unclear. The purpose of this dissertation was to: 1) clarify the controversy concerning the activation of AMPK in response to endurance-like exercise in aged skeletal muscle; 2) address mechanisms for the age-associated alterations in AMPK activation; and 3) address the known benefits of chronic AICAR treatment in aged skeletal muscle. First, to clarify the effect of age on AMPK activation, young adult (YA) (8 mo.) …