Research Methods in Life Sciences Commons^™

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 …

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 …

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 …

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 …

Role Of No In The Regulation Of Cortisol Synthesis In Long-Term Hypoxic Sheep Fetal Adrenal, Tshepo Rothi Monau

Loma Linda University Electronic Theses, Dissertations & Projects

Our laboratory has demonstrated that sheep fetuses adapt to long-term hypoxia (LTH) by maintaining normal level of basal plasma cortisol despite increased adrenocorticotropic hormone (ACTH). But the mechanisms involved are not fully understood. Studies have shown that nitric oxide (NO) inhibits synthesis of steroid hormones in a variety of tissues, and in different animal species. Studies also showed that hypoxia increases both expression and activity levels of the nitric oxide (NO) generating enzyme, nitric oxide synthase (NOS), in certain tissues. We have here investigated the expression level and localization of NOS isoforms in sheep fetal adrenals. We also investigated the …

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 …

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 …

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 …

Localization Of Sodium, Potassium-Adenosine Triphosphatase In The Cerebral Cortex Of Developing Rats, Maki Ujiie

Loma Linda University Electronic Theses, Dissertations & Projects

Active transport via Na⁺, K⁺-ATPase plays an important role in establishing and maintaining proper ionic gradient across all mammalian cell membranes. A strict regulation of Na⁺, and K⁺ ion levels is especially important in excitable cells such as neurons and myocytes. Inhibition of the enzyme is associated with several pathological conditions and has serious detrimental effects on cerebral cortical cells. Yet the enzyme appears to be limited in amount and distribution in newborn rats. In this study, Na_⁺, K⁺- ATPase expression and distribution in early postnatal rats were studied …

A Model Using Radiation And Pws4-Htnf-Α Gene Therapy For Treatment Of Glioblastomas, Angelo G. Baher

Loma Linda University Electronic Theses, Dissertations & Projects

The efficacy of radiotherapy for cancer is limited by the dose that can be safely delivered to the tumor without causing debilitating side effects. In addition, successful treatment of highly malignant tumors such as glioblastomas is likely to require adjunctive therapies to enhance tumor response to radiation. Previous studies have shown immunomodulation and a synergestic reduction in tumor volume of malignant tumors when tumor necrosis factor-α (TNF-α) protein is administered prior to radiation. The major goal of the present investigation was to evaluate the efficacy of pWS4-human TNF-α (pWS4-hTNF-α), a new plasmid construct that expresses human TNF-α protein, together with …

Proto-Oncogene Regulation By Growth Factors In Bone Cells, Harold Lyndon Merriman

Loma Linda University Electronic Theses, Dissertations & Projects

Previous studies have shown that bone cells in culture produce a number of growth factors that are important in bone regulation. Chick and mouse primary calvarial cultures consist of a mixture of cell types that make it difficult to interpret the results from these model systems. In contrast, MC3T3-E1 cells are a clonal mouse osteoblast-like cell line. Since MC3T3-E1 cells consist of a single population of calvarial cells, they make an ideal system in which to study the autocrine effects of bone growth factors.

Based on this work, MC3T3-E1 cells are now known to produce IGF-I, TGF-beta and IGF-II in …

The Inhibition Of Bone Formation Occurring Under Weightlessness : The Effect Of Skeletal Unloading On Serum Levels Of A Bone-Derived Growth Factor, Jean D. Sibonga

Loma Linda University Electronic Theses, Dissertations & Projects

A deleterious effect of spaceflight on human health is the loss of bone associated with the prolonged lack of gravitational stress on the skeleton. A potential for bone loss is indicated by the hypercalciuria and decreased heel bone density determined in Skylab astronauts. Histological studies of juvenile laboratory rats in actual spaceflight and in simulation models document a suppression of bone formation with little alteration of bone resorption. The mechanism for net bone loss needs to be defined in order to develop measures for its prevention or correction.

Skeletal growth factors, which may mediate coupling and locally regulate bone volume …

Decreased Triiodothyronine Binding To The Hepatic Nuclear Thyroid Hormone Receptor In The Diabetic Mouse, Thomas J. Dewind

Loma Linda University Electronic Theses, Dissertations & Projects

The diabetic C57BL/KsJ-db m mouse has abnormal thyroid hormone levels and indications of thyroid hormone resistance. To investigate the basis of these abnormalities, the hepatic nuclear thyroid hormone receptor was extracted with 0.4 M KCl, 1.1 mM MgCl₂, 20 mM Tris/HCl, pH 7.9 from hepatocyte nuclei of normal C57BL/KsJ, heterozygous C57BL/KsJ-db m (db/m), and diabetic C57BL/KsJ-db m (db/db) mice. Normal and heterozygous mice were grouped together as the controls. Triiodothyronine (T₃) binding studies at 4°C using nitrocellulose filtration to separate free T₃ from receptor bound T₃ demonstrated an …

Interaction Of Putative Estrogens And The Estrogen Receptor System In Leydig Cells In The Balb/C Mouse Testis Resulting In The Initiation Of Dna Synthesis, R. Lloyd Juriansz

Loma Linda University Electronic Theses, Dissertations & Projects

Continuous administration of estrogens for 7-9 months, both steroidal and nonsteroidal, to male BALB/c mice, leads to the formation of testicular Leydig cell tumors. Three days following the subcutaneous implantation of a pellet of estrogen in cholesterol, there is a peak in the incorporation of ³H-tymidine into the DNA of the interstitial cells. These effects are hypothesized to be mediated by the estrogen receptor system in the Leydig cell. Common experimental techniques for the measurement of hormone binding, such as dextran coated charcoal treatment, proved to be impossible to employ in this system, therefore a procedure was developed using …

Human Placental Alkaline Phosphatase And Steroid Metabolism By Rat Adrenals, Allen G. Meier

Loma Linda University Electronic Theses, Dissertations & Projects

Human placental alkaline phosphatase was purified by butanol extraction, methanol precipitation and chromatography on DEAE-cellulose. The pH optimum was found to be 10.9. The enzyme was competitively inhibited by di-ethyl-p-nitrobenzyl-phosphonate and copper sulfate. An increase in enzymatic activity occurred in the presence of the phosphate ion (HPO₄) and ATP.

The enzyme was crystallized from a 40% saturated solution of ammonium sulfate and shown to be homogeneous by sedimentation analysis. Homogeneity of the enzyme was also demonstrated using poly-acrylamide-gel-electrophoresis. At a pH of 7.5% the electrophoretic pattern yielded a single band and showed no significant contamination.

The metabolic transformation …

The Transfer Of Hydrogen In The Reduction Of Progesterone, William H. Kersey

Loma Linda University Electronic Theses, Dissertations & Projects

Experimental female rats were given daily injections of synthetic estrogens for six months. The effect on rat ovarian 20α-OH-SDH was not definitive. Diethylstilbestrol and 17α-ethynylestradiol caused a significant drop in activity as compared with controls while mestranol caused a slight increase in activity. A synthetic progestin, medroxyprogesterone, had no apparent effect on the activity of the enzyme.

Rat ovarian 20α-OH-SDH was purified fivefold by ammonium sulfate fractionation and chromatography on DEAE-cellulose.

The homogeneity of the enzyme was checked by means of disc gel electrophoresis. At pH 8.2 no significant contamination appeared in the electrophoretic pattern, but at pH 9.0 five …

A Comparative Study Of The Growth Of Polyoma Virus In Two Secondary Cell Lines: Mouse Lymphoma And Normal Mouse Fibroblasts, Rheeta M. Stecker

Loma Linda University Electronic Theses, Dissertations & Projects

In comparing the growth of polyoma virus in secondary cell cultures of a mouse lymphoma (P388D₁, a known polyoma-supporting strain) and normal mouse fibroblasts (Earle’s L cells), the following observations have been made.

The L cell is capable of supporting the growth of the polyoma virus with reproduction and release of infectious particles. Viruses appear in the fluid from time to time over a period of several weeks. This probably represents a carrier state of the virus in L cells. Many of the L cells in infected cultures are not killed by the virus infection.

Virus particles released …