Life Sciences Commons^™

From Young To Old: The Effects Of Sedentary-Aging And Exercise Interventions On Structural Plasticity Of Lumbar Motor Neurons, Nmj, And Glial Cell Line-Derived Neurotrophic Factor Expression, Alberto Felipe Cintron-Colon

Dissertations

Neuromuscular weakness has been associated with age progression. A possible reason is a disconnection between muscle and neuron, causing components from both the central and peripheral nervous systems to deteriorate. Exercise, however, has beneficial effects for both muscle and nervous tissue, inducing neuroprotection. Neurotrophic factors are powerful regulators of neuronal maintenance and synaptic strength. Glial cell line-derived neurotrophic factor (GDNF) is a neurotrophic factor that has been shown to be a potent survival factor for somatic motor neurons that innervate skeletal muscle.

This study aims to evaluate changes in structural plasticity of motor neurons in the lumbar spinal cord and …

Exercise Alters Glial Cell Line-Derived Neurotrophic Factor (Gdnf) Protein Content In The Spinal Cord, Monica Janine Mccullough

Dissertations

Neurotrophic factors may play a role in exercise-induced neuroprotective effects; however, it is not known if exercise mediates changes in glial cell line-derived neurotrophic factor (GDNF) protein levels in the spinal cord. The aim of the studies described herein was to determine if exercise alters GDNF protein expression in the lumbar spinal cord of healthy and diseased animals. The lumbar spinal cord was analyzed from adult rats aged 6-, 12-, 18- and 24-months, and from transgenic amyotrophic lateral sclerosis (ALS) mice and wild-type mice aged 3 months. Animals had undergone either forced wheel running, voluntary wheel running or swimming for …

Female Collegiate Gymnasts And Experiences In Sport Retirement Due To Injury, Coleen Harrington Barry

Dissertations

There has been very limited research on sport retirement concerning the experiences that female collegiate athletes face when retiring from a sport due to injury. The purpose of this qualitative study was to explore, understand, and describe experiences that former NCAA Division I female gymnasts had when they retired from gymnastics, part-way through college, due to injury. The main objective of the study was to attempt to understand female collegiate gymnasts' sport retirement experiences and the impact these experiences may have had on their identity development and college experience. The study also considered female collegiate gymnasts' perceived needs and coping …

Mapk Survival Signaling In Melanoma, Matthew W. Vanbrocklin

Dissertations

Extracellular signals activate mitogen-activated protein kinase (MAPK) cascades potentiating biological activities such as cell proliferation, differentiation, and survival. Constitutive activation of MAPK signaling pathways is implicated in the development and progression of many human cancers, including melanoma. Mutually exclusive activating mutations in NRAS or BRAF are found in ∼85% of all melanomas resulting in constitutive activation of the MAPK pathway (RAS-BRAF-MEK-ERK-RSK). We have previously demonstrated that inhibition of this pathway with small molecule MEK inhibitors selectively induces apoptosis in human melanoma cells both in vitro and in vivo, but not in normal melanocytes. These results support the notion that the …

Molecular Analysis Of The Effects Of Atrazine On Xenopus Laevis Frogs, Ronald Edward Celestine

Dissertations

Atrazine, the most commonly used herbicide in the U.S., has been implicated as one of the factors that may be causing the worldwide decline of amphibians. First, I examined effects of atrazine on laboratory raised Xenopus laevis tadpoles, treated from 5 days post fertilization to NF stage 65/66 with a concentrationof 25 ppb of atrazine. This study showed no significant difference in body weight, length and metamorphic rate.

Second, I used DNA microarrays to examine mRNA expression levels of genes in atrazine treated and control Xenopus laevis tadpoles. I found significant changes in gene expression levels of 18 genes. These …

Methylphenidate Effects On The Learning And Performance Of Four Hyper Active Children, Paul James Yoder

Dissertations

The effects of methylphenidate hydrochloride (Ritalin) on the learning and performance of four hyperactive children were evaluated using a repeated acquisition procedure with both learning and performance components. Three dosages of methylphenidate plus a placebo were evaluated under double-blind experimental conditions. Dosages treated included each subject's therapeutic dosage, a dosage 5 milligrams higher, and a dosage 5 milligrams lower. Methylphenidate produced no effect on either the number of errors per session or on the rate of responding across the range of dosages tested suggesting that the medication neither facilitated nor impaired learning or performance. Data were also collected on social …