Biochemistry Commons^™

Signaling Pathways In Skeletal Development And Metabolism, Richard Charles Lindsey

Loma Linda University Electronic Theses, Dissertations & Projects

Osteoporosis, a disease characterized by low bone mass and microarchitectural deterioration, causes nine million debilitating fractures annually. An increase in bone resorption not adequately compensated by a corresponding increase in bone formation is the major cause of osteoporosis. Since current therapies have failed to effectively eliminate osteoporosis, there is an urgent need to discover novel mechanisms regulating bone resorption and formation and develop new therapeutic approaches to treat this disease. To that end, we have explored novel, non-canonical signaling mechanisms of two well-established regulators of bone: thyroid hormone (TH) and vitamin C (ascorbic acid, AA). Since previous studies have shown …

A Novel Exo-Proteomic Approach To The Study Of Traumatic Brain Injury, Ron B. Moyron

Loma Linda University Electronic Theses, Dissertations & Projects

Concussions and Traumatic Brain Injuries (TBI) are significant health concerns and affect a wide cross section of society. Current diagnostic criteria and modalities, such as brain imaging and subjective measures of consciousness such as the Glasgow Coma Scale (GCS) score, are insufficient to properly diagnose the full spectrum of head injuries. Assessment of injury severity and outcome are further complicated by the vast array of symptoms, many of which mimic those displayed by other disorders. It is important to possess a better diagnostic tool for head injury triage and outcome prediction. One current line of inquiry seeks to discover a …

Rna-Seq Reveals Transcriptomic Program Associated With Stemness In Taxane Resistant Prostate Cancer, Christina K. Cajigas-Du Ross

Loma Linda University Electronic Theses, Dissertations & Projects

There is no cure for advanced prostate cancer (PCa), and taxane chemotherapy is the only treatment option once other therapies have failed. However, this is problematic since all patients eventually develop chemoresistance. Emerging treatments for advanced PCa have shown promise at the benchside, but clinical trials have not resulted in newly approved drugs due in part to redundant survival pathways utilized by prostate tumor cells to maintain therapy-resistance. Using RNAsequencing—an innovative approach for quantifying gene expression changes—this dissertation sought to elucidate chemoresistance-associated molecular pathways as a catalyst to develop new therapeutic targets. Results revealed a differential upregulation of stemness-associated genes …

Aryl Hydrocarbon Receptor Mediated Restoration Of Cytoglobin As A Treatment For Breast Cancer, Leah Kathleen Rowland

Loma Linda University Electronic Theses, Dissertations & Projects

Nearly 40,000 women die annually from breast cancer in the US. Clinically available targeted breast cancer therapy is ineffective in triple negative breast cancer (TNBC) subtypes, which lack expression of the estrogen receptor, progesterone receptor and human epidermal growth factor receptor 2. TNBC carries a poor prognosis. Previous reports show that aryl hydrocarbon receptor (AhR) agonist 2-(4-amino-3-methylphenyl)- 5-fluorobenzothiazole (5F 203) selectively inhibits the growth of breast cancer cells including those of the TNBC subtype. In the current study, we determined that 5F 203 induces the expression of epigenetically silenced putative tumor suppressor gene cytoglobin (CYGB) and suppresses TNBC cell growth …

Pain And Stress In The Premature Infant, John Bryle Chong Tan

Loma Linda University Electronic Theses, Dissertations & Projects

Procedural pain and stress in premature neonates is currently assessed utilizing tools that lack objectivity and accuracy. This results in untreated or mismanaged pain. My dissertation utilized physiological methods and biochemical markers that identified pain in premature neonates and its effect on energy metabolism. The painful procedure that I examined is the retinopathy of premature (ROP) examination, a necessary and routine eye examination in the neonatal intensive care unit (NICU) that detects and identifies infants at risk for blindness due to retinal detachment. The effects of the ROP exam on peripheral and deep tissue oxyhemoglobin saturation and urinary purine degradation …

Effect Of Extracellular Survivin And Lymphoma Exosomes On Natural Killer Cells, Heather R. Ferguson Bennit

Loma Linda University Electronic Theses, Dissertations & Projects

Tumors alter their microenvironment to promote survival using methods such as angiogenesis promotion, growth signals, and immune suppression. The immune system becomes unresponsive to transformed neoplastic cells through a variety of methods including T cell suppression, increased myeloid-derived suppressor cells (MDSCs), and reduced natural killer (NK) cell activity. NK cells have inherent killing capabilities and thus are among the first responders in recognizing and destroying abnormal cells. However, many types of cancers inhibit the surveillance and cytotoxic abilities of NK cells by releasing exosomes, vesicles that can modulate the tumor microenvironment (TME) and intercellular communication for the purpose of enhancing …

A Novel Population Of Cardiovascular Progenitors Persist In Neonates As Mesendodermal Cells, Julia Kim

Loma Linda University Electronic Theses, Dissertations & Projects

The rise in mortality due to cardiovascular disease has increased the need to develop an efficient regenerative therapeutic for heart failure. Numerous cell-based therapies have been investigated for myocardial regeneration; however, an optimal progenitor has yet to be discovered. Identifying a resident cell population with enhanced ability to differentiate into multiple lineages would greatly contribute to the field of stem cell-based regenerative therapy. Evidence suggests that endogenous cardiovascular progenitor cells (CPCs) that have been isolated from the heart itself express ISL1, KDR, and MESP1, and are capable of differentiating into all major cardiac lineages. The earlier developmental stage at which …

Proteomic Profiling Of Serum Derived Exosomes From Prostate Cancer Patients, David Turay

Loma Linda University Electronic Theses, Dissertations & Projects

Touted among the major achievements in the diagnosis and management of Prostate cancer (PCa) in the past few decades has been, the dramatic decline of men with advanced/metastatic PCa at diagnosis coupled with a significant improvement ( >90%) in the five and ten year survival rates of the disease. Non-palpable PCa (potentially clinically treatable disease) now accounts for 70-80% of all newly diagnosed cases of PCa. Preceding these changes by about a decade was the introduction of Prostatic Specific Antigen (PSA) into clinical practice; first as biomarker for monitoring response to therapy and subsequently as a complementary screening tool. It …

Factors Promoting Human Papillomavirus Mediated Cervical Carcinogenesis, Yan Chen Wongworawat

Loma Linda University Electronic Theses, Dissertations & Projects

High-risk human papillomavirus (HPV) is the causative agent of cervical cancer. Integration of the HPV genome into the host genome is a key event in cervical carcinogenesis, with oxidative stress (OS) likely playing a major role in promoting DNA damage, and subsequently, integration. In our current study, we demonstrated a chain of events leading from the induction of OS, to DNA damage, and then to viral integration. Induction of OS by either virus-mediated factors, such as expression of E6*, a splice variant of the E6 oncogene, or by exogenous factors led to DNA damage in normal oral keratinocytes and in …

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 …

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 …

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 …

Hpv16 E6* Induces Oxidative Stress And Dna Damage, Vonetta M. Williams

Loma Linda University Electronic Theses, Dissertations & Projects

High risk types of Human Papillomavirus are the causative agents of virtually all cases of cervical cancer, 50-90% of other anogenital cancers and approximately 30% of oral and pharyngeal cancers. The high-risk types encode two viral oncogenes, E6 and E7, which work together to initiate cell transformation. The approximately 50 amino acid product of the E6* transcript is expressed during the early stages of HPV infection. In this study, we found that expression of E6* increased the level of reactive oxygen species (ROS) in both HPV+ and HPV- cells. This increased oxidative stress led to higher levels of DNA damage. …

Quantitative Characterization Of Conserved Noncoding Regions By Flow Cytometry, Amber Brown

Loma Linda University Electronic Theses, Dissertations & Projects

Spatial and temporal regulation of developmental gene transcription often involves regulatory sequences found in noncoding DNA separate from the gene’s promoter. Conservation of a noncoding region (CNR) across divergent species may indicate a regulatory region critical to basic morphogenesis. CNR-green fluorescent protein (GFP) constructs can demonstrate spatial and temporal CNR activity by microscopy visualization. However, characterization of regulatory modules within a CNR requires quantitative, in addition to qualitative, analysis. The study presented here describes the development and implementation of a novel application of flow cytometry in the quantitative characterization of CNRs. The technique couples fluorescent microscopy localization with flow cytometry …

Exosomal Survivin-T34a: A Novel, Potential Cancer Therapeutic, Jonathan Richard Aspe

Loma Linda University Electronic Theses, Dissertations & Projects

Pancreatic cancer is the fourth most common cause of cancer fatality in American men and women with a less than 5% survival rate. Currently, if diagnosed early, surgical resection remains the only viable cure. However, only 20% of pancreatic cancer patients meet these criteria. It is therefore necessary to discover new therapies or therapeutic combinations in order to impact significantly this deadly disease. The anti-metabolite agent Gemcitabine is currently being employed to treat pancreatic cancer. While Gem-citabine has shown significant benefit in clinical applications, its ability to more than modestly impact pancreatic cancer is limited. It has been speculated that …

Effect Of Maternal Hypoxia On Fetal Development: Programming Of Hie Phenotype In Neonatal Rat Brain, Pablo J. Gonzalez-Rodriguez

Loma Linda University Electronic Theses, Dissertations & Projects

Developmental programming of health and disease correlates the adverse intrauterine environment and the risk of disease later in life as cardiovascular disease, metabolic diseases, renal dysfunction or neurobehavioral disorders among others. Maternal hypoxia is one of the most common intrauterine growth restricted environment during pregnancy. Perinatal hypoxic-ischemic encephalopathy is an important cause of brain injury in the newborn due to a systematic asphyxia. Our study aims to test the hypothesis that maternal hypoxia affect the organogenesis of the kidney by affecting the kidney structure and focusing on the roles of AT1R and AT2R, while the brain development will also be …

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, …

Ricin B Chain-Insulin Fusion Protein Immunomodulation Of Type 1 Diabetes, James Edward Carter Iii

Loma Linda University Electronic Theses, Dissertations & Projects

Type 1 diabetes mellitus (T1D) is a debilitating chronic inflammatory disease of the insulin-producing pancreatic islet β-cells that results from a combination of genetic and environmental factors. Attempts to suppress Th1-mediated autoimmune diseases such as T1D by mucosal delivery of autoantigens for immunotolerization have yielded only partial success. Attainment of satisfactory levels of sustained immunological tolerance remains to be accomplished. To restore self-tolerance requires delivery of sufficient amounts of autoantigen to stimulate regulatory T helper cells that function to survey the gut and induce tolerance to consumed antigens such as food. Oral delivery of autoantigens has previously been shown to …

Effects Of Spaceflight On Phagocytic Function And Immune-Neural Interaction, Farnaz P. Baqai

Loma Linda University Electronic Theses, Dissertations & Projects

In spaceflight, astronauts will be exposed to several environmental risk factors that may lead to disturbances in homeostasis maintained by the central nervous system (CNS) and immune system. Low Earth orbit (LEO) spaceflight studies have shown that microgravity changes virtually all immune parameters that have been evaluated. Similarly, ground based studies have shown that low-dose radiation can also significantly impact immune function. Finally, as most spacecrafts are ecologically and environmentally closed systems, astronauts may be at increased risk for exposure to aerosolized infectious agents. The hypothesis of this study is: Exposure to spaceflight environment (microgravity and radiation) can influence immune …

Fetal Cocaine Exposure Causes Epigenetic Changes In The Rat Heart, Kurt D. Meyer

Loma Linda University Electronic Theses, Dissertations & Projects

Cocaine abuse continues to be prevalent in the United States and other industrialized nations, in addition to the negative health effects that cocaine abuse has on the user, a mother who uses cocaine while pregnant also exposes the developing fetus to cocaine. Although there have been many studies of the effects of cocaine on the adult heart, studies of cocaine on the fetal heart and its potential delayed pathophysiological effects on cardiac function in adult offspring are extremely limited. The studies of the present project sought to enhance the understanding of the effect of cocaine exposure on the fetal heart …

Mnte-2-Pyp And Radiation In A Prostate Cancer Model: Implications For Radiotherapy, Adeola Y. Makinde

Loma Linda University Electronic Theses, Dissertations & Projects

A major limitation of successful radiation therapy in cancer treatment is the increase in normal tissue damage as higher doses are used to achieve greater tumor destruction. Radiation dose optimization in cancer therapy requires achieving maximum tumor destruction with minimal damage to normal tissue Antioxidants have been shown to protect normal tissues against radiation damage, as radiation-induced tissue damage results predominantly from reactive oxygen species that directly damage cellular components. However, for effective use as normal tissue radioprotectants in radiotherapy, these antioxidants must not protect the tumors. Mn (III) tetrakis (N-ethylpyridinium-2-yl) porphyrin (MnTE-2-PyP) is a metalloporphyrin antioxidant that has been …

Hypochlorous Acid Mediated Damage Of Chromatin, Joseph Insugn Kang

Loma Linda University Electronic Theses, Dissertations & Projects

Hypochlorous acid (HOCl), the primary product of activated neutrophils at sites of inflammation, can damage both DNA and associated histone proteins. HOCl damage to cytosine bases in DNA generates the chlorination damage products 5-chlorocytosine (ClC) and 5-chlorouracil (ClU) as well as the oxidation damage products 5- hydroxycytosine (HOC) and 5-hydroxyuracil (HOU). Histone damage by HOCl can be measured by quantitation of 3-chlorotyrosine and 3,5-dichlorotyrosine, stable and unique markers of protein damage caused by HOCl. The studies presented here investigate how and where these damage products occur and what implications they might have in the correlation between chronic inflammation and carcinogenesis. …

Biochemical Characteristics Of Inconsistent Free T₄ Assays, Kristofer S. Fritz

Loma Linda University Electronic Theses, Dissertations & Projects

Serum levels of free thyroxine (T₄) are helpful in the clinical evaluation of patients who are suspected of having thyroid disease, since free T₄ (unbound) is known to closely relate to hyper, eu and hypothyroidism. There are documented inconsistencies among commercially available direct free thyroxine immunoassays. The biochemical basis for these inconsistencies is not understood and has not been characterized. Direct free T₄ measurements have been linked to both T₄-binding serum protein concentrations and protein-bound T₄ concentrations. A free T₄ reference method using direct equilibrium dialysis radioimmunoassay has been well characterized. New …

Iron Dysregulation And Inflammation In Alzheimer’S Disease, Shino D. Magaki

Loma Linda University Electronic Theses, Dissertations & Projects

Alzheimer’s disease (AD) is the most common form of senile dementia in the US and worldwide but the causes of its pathogenesis are currently unknown. In this study, we examined two processes that have been implicated in the early stages of AD and other forms of neurodegeneration, iron dysregulation and inflammation, both of which can promote the increased production of amyloid precursor protein (APP). We have measured different pools of brain iron in transgenic iron regulatory protein 2 knockout (IRP2-/-) mice in the early stages of neurodegeneration and in affected brain regions from AD patients at different stages of the …

Radiation-Induced Increases In Pkc Modulate Integrin Expression And Contribute To Fibrotic Changes, Pinal Rushikesh Pandya

Loma Linda University Electronic Theses, Dissertations & Projects

The sequences of events in fibrosis are similar to those in wound healing; however, the normal termination and resolution stages do not take place. The initial cellular response following ionizing radiation involves accumulation of the ECM (extracellular matrix) including collagen, fibronectin and the interaction of many growth factors (cytokines) with their receptors. There are a number of unanswered questions regarding many aspects of radiation-induced fibrosis, including the initial triggers and physical changes that initiate the process. We have confirmed that elevated pKC and other cellular changes following radiation are similar to those found at sites of inflammation. This information leads …

Membrane Organization And Multimeric Interactions Of The Aer Receptor In E. Coli, Divya Dashrathkumar Amin

Loma Linda University Electronic Theses, Dissertations & Projects

Escherichia coli swims toward niches ideal for generating maximum energy by monitoring the environment with the aerotaxis sensor, Aer. This receptor has an N-terminal PAS domain, which is a sensor module present in a variety of proteins from all kingdoms of life (including humans). To date, the mechanism of signaling from a PAS sensor domain to a single signaling receiver domain has not been resolved. In Aer, the PAS sensor is separated from the signaling region by a membrane anchor. Most "transmembrane prediction" programs forecast a single membrane span for this membrane anchor, but such a topology is inconsistent our …

Mechanisms Of Hbo-Induced Neuroprotection In A Neonatal Hypoxia-Ischemia Model, John Winter Calvert

Loma Linda University Electronic Theses, Dissertations & Projects

With an incidence approaching 1/4000 live births and as high as 60% in low birth weight infants, cerebral hypoxia-ischemia during the perinatal period is the single most important cause of acute mortality and chronic disability in newborns. Herein, we tested the hypothesis that following a hypoxic-ischemic insult hyperbaric oxygen (HBO) treatment can restore high energy metabolite levels in the affected regions of the brain and through this increase in energy levels ameliorate the spread of cell death following the insult. We also investigated if an additional mechanism by which HBO affords its neuroprotection is by altering the expression of the …

P14arf : A P53-Independent Tumor Suppressor, Monte W. Miller

Loma Linda University Electronic Theses, Dissertations & Projects

Many genetic alterations at the CDKN2A locus on human chromosome 9 have been shown to be at least partially responsible for transformation of cells to a cancerous phenotype. This locus encodes two proteins, p16 and p14, that play a pivotal role in tumor surveillance.

Breakdowns in the p14 pathway have been estimated to be present in approximately 40% of human cancers and only recently have its binding partners and effects begun to be defined. Its interaction with the p53 pathway, which is estimated to be inactivated or mutated in 50% of all cancers, makes it difficult to determine its own …

Enterotoxin B Subunit Lectins As Adjuvants For Improvement Of Mucosal Vaccine, Nak-Won Choi

Loma Linda University Electronic Theses, Dissertations & Projects

In comparison with whole organism vaccines, subunit vaccines may be safer for immunization but may lack sufficient immunogenicity to provide complete immunity to the pathogen. To resolve this problem, bacterial and plant enterotoxin B subunit adjuvants containing a variety of receptor-binding properties were used to enhance the immunogenicity of rotavirus subunit vaccines. Enterotoxin B subunit adjuvants were employed to enhance protection against virus infection. Pentameric cholera toxin B subunit (CTB), shiga toxin-1 B subunit (STB) and monomeric ricin toxin B subunit (RTB) molecules were genetically linked to a 90 amino acid peptide from the simian rotavirus (SA11) nonstructural protein NSP4 …

Prediction Of Fetal Sheep Brain Metabolic Rate During Hypoxia And Cord Occlusion, Adam D. Hickerson

Loma Linda University Electronic Theses, Dissertations & Projects

Many investigators have observed that fetal and neonatal animals are remarkably tolerant to hypoxia compared to the adult. The precise mechanisms however are still unclear. In order to better characterize the hemodynamic and metabolic responses of the fetal brain to hypoxic stress, we have designed a mathematical model to predict tissue oxygenation and metabolic rate of the fetal brain during both moderate hypoxia and severe asphyxia.

The model is based on the Krogh cylinder concept and is similar to one previously published by our lab. Several new concepts were added including the ability to run the model over time using …