Medicine and Health Sciences Commons^™

Effects Of Neonatal Dexamethasone On The Maturation And Endowment Of Cardiomyocytes, Maresha Gay

Loma Linda University Electronic Theses, Dissertations & Projects

Each year 1 in 9 infants are born preterm in the United States. Preterm infants have a host of complications associated with prematurity, including respiratory distress syndrome. Dexamethasone, a synthetic glucocorticoid is the ‘gold standard’ intervention in the treatment of preterm infants and mothers at risk of preterm birth because it promotes organ maturation, particularly the lungs and aids in surfactant production. However, a growing body of evidence suggests perinatal dexamethasone exposure is associated with health consequences later in life including increased risk of cardiovascular disease. Cardiomyocytes are the functional unit of the heart and are unique in that they …

Comparative Studies Of Tslp And Il-7 In Normal Early Human Neonatal And Adult B Cell Development, Terry-Ann Milford

Loma Linda University Electronic Theses, Dissertations & Projects

Defining the role of cytokines in promoting human B cell development is important for understanding B cell leukemia and for developing strategies to restore B cell production that is lost during some therapies. The purpose of this study was to investigate the roles of the IL-7R ligands, thymic stromal lymphopoietin (TSLP) and IL- 7, in the early stages of normal postnatal and adult human B cell development. Using novel in vitro and in vivo model systems, we show that TSLP and IL-7 are able to expand B cell precursors individually and in combination from CB hematopoietic stem cells. In this …

Role Of Slit2 In Reducing Complications After Surgical Brain Injury, Prativa Sherchan

Loma Linda University Electronic Theses, Dissertations & Projects

Surgical brain injury (SBI) is the inadvertent injury to brain tissue at the perisurgical site which occurs due to neurosurgical maneuvers such as incision, retraction, and electrocoagulation that can result in post-operative complications. Blood brain barrier (BBB) disruption and neuroinflammation are major pathophysiological consequences after neurosurgical injury. Blood brain barrier dysfunction leads to increased influx of water and plasma proteins as well as peripheral immune cell infiltration into the brain parenchyma that further potentiates brain edema and worsens post-operative neurological function. Activated resident immune cells and infiltrated peripheral immune cells release inflammatory mediators and promote oxidative stress and cell death …

Palmitic Acid Activation Of Dendritic Cells: Implications For Type 2 Diabetes, Dequina Angelina Nicholas

Loma Linda University Electronic Theses, Dissertations & Projects

Infiltration of immune cells into visceral adipose tissue is observed in type 2 diabetes development. Monocytes are recruited to obese visceral adipose tissue in large numbers and retain the ability to differentiate into dendritic cells, important antigen presenting cells in the immune system. Differentiation of monocytes into dendritic cells likely accounts for the increased number of dendritic cells observed in the adipose tissue of type 2 diabetic patients. We have demonstrated this differentiation process is regulated in part by a major reduction of linker histone proteins. In adipose tissue, dendritic cells are exposed to high levels of saturated fatty acids. …

Dietary Intake And Bio-Activation Of Nitrite And Nitrate In Newborn Infants, Jesica Ann Jones

Loma Linda University Electronic Theses, Dissertations & Projects

Nitrate and nitrite are commonly thought of as inert end products of nitric oxide (NO) oxidation, possibly carcinogenic food additives, or well-water contaminants. However, recent studies have shown that nitrate and nitrite play an important role in cardiovascular and gastrointestinal homeostasis through conversion back into NO via a physiological system involving enterosalivary recirculation, bacterial nitrate reductases, and enzyme-catalyzed or acidic reduction of nitrite to NO. The diet is a key source of nitrate in adults; however, infants ingest significantly less nitrate due to low concentrations in breast milk. In the mouth, bacteria convert nitrate to nitrite, which has gastro-protective effects. …

Tslp-Induced Mechanisms And Potential Therapies For Crlf2 B-Cell Acute Lymphoblastic Leukemia, Olivia L. Francis

Loma Linda University Electronic Theses, Dissertations & Projects

Childhood CRLF2 B-cell Acute Lymphoblastic Leukemia (CRLF2 B-ALL) is a high-risk form of leukemia that is associated with poor patient survival outcomes. CRLF2 B-ALL is five times more prevalent in Hispanic children than others and is associated with a higher rate of relapse, thus contributing significantly to childhood cancer health disparities. This disease occurs due to alterations of the CRLF2 gene, leading to overexpression of the CRLF2 protein- a component of the receptor signaling complex for the cytokine Thymic Stromal LymphoPoietin (TSLP) on the surface of B-ALL cells. TSLP has been shown to induce proliferation of human and mouse B-cell …

Crotalus Snake Venom Preconditioning To Prevent Surgical Brain Injury, Cherine Hee-Sun Kim

Loma Linda University Electronic Theses, Dissertations & Projects

Preventive measures are increasingly relevant to medical practice. Preconditioning, a preemptive therapy that administers mildly harmful stimuli to induce endogenous protective mechanisms before major injury, has been shown to minimize injury in many animal models. Given the elective nature of most neurosurgical procedures, the surgical brain injury (SBI) rodent model provides an ideal platform for preconditioning. Our work shows that preconditioning with Crotalus rattlesnake venom, known for its hemorrhagic and inflammatory effects, mitigates some harmful effects of SBI. We have identified two proteins of interest in Crotalus venom: snake venom metalloproteinase (SVMP), an enzyme with hemorrhagic effects, and phospholipase A2 …

Molecular Mechanisms That Govern Human Cardiac Stem Cell Age Disparity, Tania Fuentes

Loma Linda University Electronic Theses, Dissertations & Projects

Transplantation of adult endogenous cardiovascular progenitor cells for heart repair results in some clinical benefit, however these stem cells lack the regenerative capacity unique to neonatal cardiovascular stem cells. The goal of this work was to identify mechanisms that contribute to the decline of cardiac stem cell regenerative ability with age and investigate novel therapeutic strategies to improve cardiac stem cell function. When comparing neonatal and adult cardiovascular stem cell clones, both cell types were capable of cardiomyogenic differentiation. However, the expression levels of forty-one microRNAs were significantly altered with age. Expression differences were correlated with reduced proliferation and a …

Long-Term Hypoxia Alters Ovine Fetal Adrenal Enos And Cortisol Biosynthesis, Elizabeth Anne Newby

Loma Linda University Electronic Theses, Dissertations & Projects

Maintaining normal levels of cortisol in response to chronic stress, while retaining the ability to respond to acute stress, is important for ensuring normal fetal growth and development. Long-term hypoxia (LTH) causes adaptations in the fetal hypothalamopituitary- adrenal (HPA) axis that maintain basal cortisol levels but enhance production in response to a secondary stress. Nitric oxide (NO), produced by endothelial nitric oxide synthase (eNOS) in the adrenal cortex, plays a significant role in regulating cortisol production in the LTH fetus. The production of NO is regulated by eNOS activity which can be altered via phosphorylation through key signaling pathways. In …

Molecular Characterization And Inhibition Of Antibodies Elicited Against Galactosyltransferase Knockout Pig Xenografts, John M. Stewart

Loma Linda University Electronic Theses, Dissertations & Projects

On average, 21 people in the United States die every day while waiting for a transplantable organ. Moreover, at the end of 2014, nearly 130,000 additional individuals were still on the transplant waiting list. Xenotransplantation, the transplantation of cells and/or organs from a member of another species, is both a viable supplement for, and bridge to, allotransplantation. Pigs are the favored organ donor because they: 1) breed and grow rapidly, 2) can be genetically modified, and 3) present few ethical concerns. However, due in part to their phylogenetic distance, several barriers must be successfully overcome before clinical xenotransplantation can be …

Acclimatization To High-Altitude, Long-Term Hypoxia Alters Bk Channel Structure And Function, Xiaoxiao Tao

Loma Linda University Electronic Theses, Dissertations & Projects

We examined the major possible mechanisms for the left shift of the BK channel I-V relationship in native basilar artery myocytes from the two LTH groups. These mechanisms included: differential expression of the accessary BK -1 subunit; differential phosphorylation of the BK subunit; and splice variation of the BK subunit. Using molecular cloning, heterologous expression, and patch-clamp electrophysiology techniques, we elucidated a mechanism that, at least in part, contributes to the differences we observed between channels from native normoxic and LTH myocytes.

Curcumin: A Multi-Dimensional Approach To Pancreatic Cancer Targeting Cell Death And Exosomes, Carlos J. Diaz Osterman

Loma Linda University Electronic Theses, Dissertations & Projects

Pancreatic cancer is currently one of the most difficult diseases to treat due to difficulty of detection and the aggressive nature of the disease. In addition, pancreatic cancer has the highest mortality rates compared to other cancer types. These mortality rates are attributable in part to increasing resistance to cancer therapy. Cancer therapy resistance is caused by adaptations that favor survival within cancer cells and their environment, termed the tumor microenvironment. Intracellular adaptations include the overexpression of resistance-linked genes, such as the inhibitor of apoptosis (IAP) family of proteins and overall resistance to cell death. Adaptations in the tumor microenvironment …

Chlorinated Tyrosine Species As Markers Of Inflammation: A Kinetic Study, Matthew Peter Curtis

Loma Linda University Electronic Theses, Dissertations & Projects

Chronic inflammation is associated with numerous human diseases. During inflammation, leukocytes release the enzyme myeloperoxidase (MPO) which generates reactive oxygen species such as hypochlorous acid (HOCl). Additionally, MPO generates reactive nitrogen species. These reactive species can damage host fats, proteins, and DNA, contributing to disease pathology. Because of the reactivity and short half-lives of reactive species, measurement of surrogate markers is necessary to determine their extent and source. Chlorination of the tyrosine phenol ring by HOCl to produce 3-chlorotyrosine (3ClTyr) or nitration of the phenol ring by reactive nitrogen species to produce 3-nitrotyrosine (NO2Tyr) are two such markers. Both are …

Lipid Regulation As A Critical Factor In The Development Of Alzheimer's Disease, Michael A. Castello

Loma Linda University Electronic Theses, Dissertations & Projects

Alzheimer’s disease (AD) is the most common form of dementia in the United States, representing around eighty percent of all cases. For more than two decades, researchers have been led by the amyloid cascade hypothesis, which assumes that accumulation of the amyloid peptide Aβ, derived by proteolytic processing from the amyloid precursor protein (APP), is the key pathogenic trigger in AD. To date, therapies have largely focused on removing Aβ from the brain, an approach that has produced disappointing clinical outcomes. I present an alternative hypothesis in which Aβ production and aggregation is a symptom of a larger, systemic disease …

Existence Of Inhibitor Of Apoptosis In Tumor Exosomes, Malyn May Asuncion Valenzuela

Loma Linda University Electronic Theses, Dissertations & Projects

Pancreatic cancer is a deadly and aggressive disease. The only option for metastatic pancreatic cancer is chemotherapy where only the antimetabolites gemcitabine (Gem) and 5-fluorouracil (5FU) are used clinically. However, resistance to these antimetabolites remains a problem highlighting the need to discover and develop new antimetabolites that will improve a patient’s overall survival. Cancer is a disease that has acquired numerous molecular, biochemical and cellular changes. Resistance to apoptosis is one of the characteristics of cancer, of which the inhibitor of apoptosis (IAP) family of proteins plays an important role. It has also been shown that cancer cells secrete vesicles …

Modulation Of T Lymphocytes By Tumor-Released Survivin, Jessica Marie Jutzy

Loma Linda University Electronic Theses, Dissertations & Projects

The tumor microenvironment is an area of intense interaction between normal and malignant cells. Factors and cell types within this environment can play a crucial role in the progression or regression of the tumor. Of primary interest are tumor-infiltrating T lymphocytes, which have been shown to have a key role in modifying the dynamics of the tumor microenvironment to promote or prevent tumor growth. While there is much in vitro and in vivo evidence for a modification of the tumor infiltrating T cell population toward a pro-tumor environment, what induces these changes within the tumor microenvironment has remained elusive. Our …

Role Of Astrocyte Network In Edema After Juvenile Traumatic Brain Injury, Andrew Minoru Fukuda

Loma Linda University Electronic Theses, Dissertations & Projects

Juvenile traumatic brain injury (jTBI) is the leading cause of death and disability in young children and adolescents. Despite its lasting detrimental effects on the developing brain, no pharmacological treatment exists. One of the pathological hallmarks of jTBI is edema. Astrocytes play a key role in the edema process, and have been hypothesized that numerous astrocyte networks allow communication and propagation of edema and secondary injury spread. Two key astrocyte proteins are hypothesized to have a central role in the edema process: Aquaporin 4 (AQP4) and Connexin 43 (Cx43). AQP4 is expressed extensively in astrocyte endfeet, which surrounds the blood …

Humor's Effect On Short-Term Memory In Older Adults: An Innovative Wellness Paradigm, Gurinder Singh Bains

Loma Linda University Electronic Theses, Dissertations & Projects

Context: With ageing, the detrimental effects of stress can impair the ability to learn and sustain memory. Humor and the associated mirthful laughter can reduce stress by decreasing the hormone cortisol. Chronic release of cortisol can damage hippocampal neurons leading to impairment of learning and memory. Objectives: To examine the effect of watching a humor video on short term memory in older adults. Design: A randomized, controlled trial. Setting: Loma Linda University, Loma Linda, CA. Participants: 30 subjects: 20 normal healthy, older adults, 11 males and 9 females; 10 Type 2 Diabetic older adults, 6 males and 4 females. Intervention: …

Retinoic Acid Regulation Of Thyroid Hormone Action In Bone Cells, Anjali Babbar

Loma Linda University Electronic Theses, Dissertations & Projects

Retinoic acid and thyroid hormone are known to play key roles in the regulation of endochondral ossification. However, the issue of whether these two hormones interact with each other to regulate bone functions remains to be established. We investigated how thyroid hormone and retinoic acid interact to regulate cells involved in endochondral bone formation. We demonstrate that thyroid hormone treatment stimulates differentiation of ATDC5 chondrocytes and promotes formation of mineralized nodules while retinoic acid treatment at high dose inhibits chondrocyte differentiation and formation of mineralized nodules. Furthermore, thyroid hormone induced mineralized nodule formation is inhibited by co-treatment with retinoic acid …

Survivin: Regulation By Yy1 And Role In Pancreatic Cancer Combination Therapy, Nicholas R. Galloway

Loma Linda University Electronic Theses, Dissertations & Projects

Despite significant clinical and basic science advancements, cancer remains a devastating disease that affects people of all ages, races, and background. Survivin, the fourth most common transcript found in cancer cells, is a protein that is thought to be involved in the enhanced proliferation, survival, and metastasis of cancer cells. Therefore understanding how this gene is regulated is potentially of vital importance to improving cancer management and therapy. Our work has identified a novel transcriptional regulator of survivin called Yin Yang 1 (YY1). YY1 is a transcription factor that has been observed to activate some gene promoters and repress others, …

Towards A Better Treatment Of Parkinson's Disease, Bradley Darryl Karain

Loma Linda University Electronic Theses, Dissertations & Projects

Current therapies for Parkinson's Disease, the second most common neurodegenerative disorder, do not prevent disease progression, and induce extremely detrimental side-effects. Improving the best current pharmacological therapy, L-DOPA, carries important clinical benefits, partly by reducing the dose-related side-effects which occur after five to ten years of use. Thus the central aim of this proposal is to determine whether low doses of a D2 antagonist may, by selectively blocking the dopamine autoreceptor-mediated feedback inhibition of dopamine neurons, potentiate L-DOPA's effect on individual basal ganglia neurons and its antiparkinsonian effects in Parkinsonian animals. Electrophysiology (extracellular single-cell recording in the globus pallidus) and …

Sympathetic Nerve Modulation Of Joint Pathology In Adjuvant-Induced Arthritis, Carlo Anthony Wood

Loma Linda University Electronic Theses, Dissertations & Projects

Background: There is increasing data suggesting a net increase in sympathetic tone plays an important role in rheumatoid arthritis. Several studies have reported altered distribution and density of autonomic nerves in patients with rheumatoid arthritis and animal models for the disease. This provides anatomical evidence that supports a neurally-mediated drive in inflammation and joint destruction. Methods: Adult rats were injected with complete Freund’s adjuvant. At 12 days post immunization, animals were randomly placed into a drug treatment group (SH1293, which interacts with - and ß2-ARs), an adjuvant arthritic group, or a control group. These animals were sacrificed at 14, 21, …

Caveolins And Njks Influence Brain Endothelial Permeability After Juvenile Tbi, David Olufemi Ajao

Loma Linda University Electronic Theses, Dissertations & Projects

Disruption of blood-brain barrier (BBB) is a key secondary event that exacerbates brain damage following traumatic brain injury (TBI). BBB disruption is particularly damaging to the developing brain – which is highly vulnerable to various stress stimuli, resulting in increased brain swelling, disrupted cerebral blood flow (CBF) autoregulation, long-term disabilities and death following TBI in young demographic. Unsurprisingly, BBB disruption and the resultant cerebral edema have emerged as therapeutic targets in juvenile TBI. It is therefore important to understand the molecular players and mechanisms involved in TBI-induced BBB disruption in the juvenile brain. To this end, the endothelial caveolins and …

Expression And Function Of Ca2+-Activated K+ Channels In Uterine Arteries, Ronghui Zhu

Loma Linda University Electronic Theses, Dissertations & Projects

Chronic hypoxia during pregnancy is one of the most common insults to the maternal cardiovascular system and fetal development, and is associated with increased uterine vascular tone and heightened risk of preeclampsia and fetal intrauterine growth restriction (IUGR). The present study tested the hypothesis that calcium-activated potassium (KCa) channels play an essential role in uterine vascular adaptation to pregnancy, which is inhibited by chronic hypoxia during gestation. Uterine arteries (UAs) were isolated from nonpregnant ewes (NPUAs) and near-term pregnant ewes (PUAs) that had been maintained at sea level (~300 m) or exposed to high altitude (3,801 m) for 110 days. …

Radiosensitization Of Head & Neck Carcinoma Cells By Linifanib, A Receptor Tyrosine Kinase Inhibitor, Heng-Wei Hsu

Loma Linda University Electronic Theses, Dissertations & Projects

Tumor angiogenesis is a hallmark of advanced cancers and promotes invasion and metastasis. Over 90% of head and neck squamous cell carcinomas (HNSCC) express angiogenic factors such as vascular endothelial growth factor (VEGF). Since radiotherapy is one of the most commonly used treatments for HNSCC, it is imperative to identify the interactions between antiangiogenic therapy and radiotherapy, and to develop combination therapy to improve clinical outcome. The mechanisms between antiangiogenic agents and ionizing radiation are complicated and involve many interactions between the vasculature, tumor stroma and tumor cells. The proliferation and metastasis of tumor cells rely on angiogenesis/blood vessel formation. …

Role Of Vimf In Gingipain Maturation In Porphyromonas Gingivalis, Arun S. Muthiah

Loma Linda University Electronic Theses, Dissertations & Projects

Gingipain activity in Porphyromonas gingivalis, the major etiological agent in adult periodontitis, is post-translationally regulated by unique Vim proteins including VimF, a putative glycosyltransferase. To ascertain the VimF mediated phenotype we first inactivated the vimF gene in P. gingivalis ATCC 33277 (FLL476), a less virulent fimbriated strain. We observed that the vimF-defective mutant (FLL476) showed a phenotype similar to that of the vimF-defective mutant (FLL95) in the P. gingivalis W83 background. While hemagglutination was not detected and autoaggregationn was reduced, biofilm formation was increased in FLL476. Also, invasive capacity decreased for this mutant. Furthermore, fimbrial structures were missing in FLL476, …

Microglia And Complement In Alzheimer's Disease With Cerebral Amyloid Angiopathy, Matthew K. Zabel

Loma Linda University Electronic Theses, Dissertations & Projects

Alzheimer’s disease (AD) is the most common form of dementia and completely lacks any viable, long-term therapeutic intervention. This is partly due to an incomplete understanding of AD etiology and the possible confounding factors associated with its genotypic and phenotypic heterogeneity. Cerebral amyloid angiopathy (CAA) is a common, yet frequently overlooked, pathology associated with AD. A pathological hallmark of AD consists of extracellular amyloid-beta (Aβ) deposits, while CAA

manifests with deposition Aβ within the smooth muscle layer of cerebral arteries and arterioles. The role of Aβ in AD and CAA pathophysiology has long been controversial. Although it may have toxic …

Effect Of Procedural Pain On Purines, Mda And Allantoin In Premature Infants, Megan Sue Holden

Loma Linda University Electronic Theses, Dissertations & Projects

Identifying and measuring the biochemical effects of procedural pain in infants is a continuing challenge for clinicians. To address this issue we evaluated the relationship between procedural pain, ATP utilization (hypoxanthine and uric acid), and oxidative stress (MDA and allantoin) in premature infants. Through these studies we found that 1) a single heel-lance significantly increases plasma uric acid in rabbit kits, 2) tape removal increases MDA and prevents a decrease in uric acid in the plasma of premature infants, and 3) a single dose of oral sucrose before a heel-lance is sufficient to significantly increase plasma markers of ATP utilization …

Vegf And Sympathetic Perivascular Nerves Contribute To Hypoxic Remodeling Of Ovine Cranial Arteries, Olayemi Olufikayo Adeoye

Loma Linda University Electronic Theses, Dissertations & Projects

Chronic hypoxia complicates many pregnancies and can result in postnatal pathologies that include compromised fetal cardiovascular structure and function. Mechanisms involved remain unclear. Because hypoxia increases production of VEGF, known to modulate smooth muscle (SM) phenotype, this thesis explored the hypothesis that VEGF contributes to hypoxic fetal vascular remodeling through direct effects on SM cells and indirectly through perivascular nerves. Using a chronic hypoxia sheep model, this work demonstrated that: 1) hypoxia potently upregulates VEGF receptor expression but not endogenous VEGF level in fetal ovine carotid arteries; 2) both chronic hypoxia and VEGF exert similar effects on smooth muscle contractile …

Perinatal Nicotine Exposure And Programming Of Hie Sensitive Phenotype In Neonatal Rat Brains, Yong Li

Loma Linda University Electronic Theses, Dissertations & Projects

Large epidemiological and animal studies have revealed a clear association of adverse intrauterine environment with the increased risk of metabolic, cardiovascular and neurological diseases. Maternal smoking is the single most widespread perinatal insult in the world and has been associated with adverse pregnancy outcomes for mother, fetus and the newborn. Our study aims to test the hypothesis that perinatal nicotine exposure induces reprogramming of susceptibility to hypoxic ischemic brain injury in the immature brain, focusing on the roles of AT1R and/or AT2R and trying to reveal the underlying epigenetic mechanisms. Therefore, we established two rat models: perinatal nicotine exposure model …