Life Sciences Commons^™

Factors Influencing Venom Expenditure During Defensive Bites By Cottonmouths (Agkistrodon Piscivorus) And Rattlesnakes (Crotalus Viridis, Crotalus Atrox), Shelton Scott Herbert

Loma Linda University Electronic Theses, Dissertations & Projects

Although the quantity of venom expended when biting is an important aspect of the natural history of snakes, little is known regarding the quantities of venom expended during bites. Recent studies have shown that rattlesnakes appear capable of selectively allocating their venom reserves during predatory strikes, metering more venom into certain prey types and less into others. Despite much speculation, the quantities of venom expended during defensive bites are poorly understood. The purpose of this study was to examine the factors that influence venom expenditure during defensive bites by cottonmouths (Agkistrodon piscivorus), western rattlesnakes (Crotalus viridis) and western diamondbacks …

Analysis Of Protein And Rna Interactions Of The Hiv-1 Rev Protein, John Francis

Loma Linda University Electronic Theses, Dissertations & Projects

The HIV-1 Rev protein enters the nucleus via it’s nuclear localization sequence/RNA binding domain and interacts with a ≈234 nt region of viral RNA, termed the Rev Response Element (RRE), which is located in the env region of unspliced and singly-spliced HIV-1 mRNA. The Rev nuclear export sequence (NES) then mediates translocation of the viral transcript to the cytoplasm, allowing for translation of viral structural genes and active virion formation. We report identification of two yeast nucleopore proteins, NUP49 and NUP100, that have been found to interact with Rev in vivo using the yeast two-hybrid system. NUP49 and NUP100 contain …

The Role Of Gap Junctions In Congenital Diseases Of The Heart, Scott Henry Britz-Cunningham

Loma Linda University Electronic Theses, Dissertations & Projects

Background. Gap junctions are thought to have a crucial role in the synchronized contraction of the heart and in embryonic development. Connexin43, the major protein of gap junctions in the heart, is targeted by several protein kinases that regulate myocardial cell-cell coupling. We hypothesized that mutations altering sites critical to this regulation would lead to functional or developmental abnormalities of the heart.

Methods. Connexin43 DNA from 25 normal subjects and 30 children with a variety of congenital heart diseases was amplified by the polymerase chain reaction and sequenced. Mutant DNA was expressed in cell culture and examined for its effect …

The Effects Of Exposure To Extremely Low-Amplitude, Low-Frequency Electric Fields On Skeletal Tissue, In Vitro, Robert James Fitzsimmons

Loma Linda University Electronic Theses, Dissertations & Projects

In vivo experiments have demonstrated (a) that transient electrical potentials are induced in impact-loaded bone, and (b) that bone formation is increased in response to electrical stimulation. Therefore, it has been hypothesized that, in response to mechanical loading, mechanical energy in bone is transduced into biologically relevant electrical energy. In order to study the mechanism through which electric fields may increase bone formation, a model system was developed were bone cells or bone organ cultures were exposed to a capacitively-coupled electric field of low frequency (8-25 Hz) and extremely low amplitude (estimated 10^-7 V/cm in the culture medium) for …

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 Pilot Study Testing A Proprietary Sealant For Plaque Reduction, Jennifer Rowland

Loma Linda University Electronic Theses, Dissertations & Projects

Enamel demineralization due to increased plaque accumulation is a well-recognized problem associated with fixed orthodontic appliances. The purpose of this study was to evaluate the efficacy of a proprietary product to be marketed by 3M Unitek for the reduction of plaque accumulation and thereby reduce enamel demineralization.

Sixty four bovine teeth were divided equally into an untreated control group and a group treated with the proprietary sealant product. Both groups were subsequently immersed in a Streptococcus mutans culture. Plaque deposits from each group were removed, suspended in trypticase soy broth, serially diluted, and plated on trypticase soy agar at 1, …

Analysis Of Serotonin And Postural Instability In Parkinson’S Disease, Sandra Kuniyoshi

Loma Linda University Electronic Theses, Dissertations & Projects

Postural instability is one of the most debilitating symptoms of Parkinson’s disease and the best clinical prognostic indicator of progressive disease. Significant differences in neuropathology, neurochemistry, response to L-dopa therapy and stereotactic surgery as well as prognosis have been identified in subtypes when patients with predominant postural instability and gait difficulty (PIGD)/Type B were differentiated from those with predominant symptoms of tremor and rigidity/Type A. Postural instability is resistant to the therapeutic effects of L-dopa, despite its continued efficacy on other Parkinson’s symptomatology, implicating the nondopaminergic mechanism of postural instability in Parkinson’s disease. Patients with significant postural instability and gait …

Transcriptional Regulation Of The Bombyx Mori A3 Cytoplasmic Actin Promoter In Insect And Mammalian Cells, Karoly Fatyol

Loma Linda University Electronic Theses, Dissertations & Projects

In this study we have analyzed the activity of the silkworm A3 cytoplasmic actin promoter in homologous insect and heterologous mammalian expression systems. To study the expression of the A3 actin promoter in insect cells we have isolated and characterized a stably transformed Bombyx mori cell line containing a novel selectable marker gene, puromycin N-acetyl transferase under control of transcriptional regulatory signals from the A3 cytoplasmic actin gene. Integration of the transfected plasmids into the host genome was demonstrated by Southern and in situhybridizations. By using this cell line we have identified alternative transcriptional initiation sites for the A3 …

Regeneration In Periodontal Defects With Rhbmp-2 : A Dosage Study, Paola Guglielmoni

Loma Linda University Electronic Theses, Dissertations & Projects

Bone morphogenetic proteins (BMPs) have been shown to induce bone formation in ectopic and orthotopic sites. This inductive capability has led to their evaluation as possible adjuncts in periodontal reconstructive therapy. Indeed, studies have reported periodontal regeneration following surgical implantation of recombinant human BMP-2. This study evaluated regeneration of alveolar bone and cementum following periodontal reconstructive surgery including implantation of a construct consisting of sterile lyophilized rhBMP-2 in buffer adsorbed onto an absorbable collagen sponge. Critical size mandibular supra-alveolar periodontal defects were surgically created, and an incomplete block design was used to evaluate the regenerative potential of rhBMP-2 at 0.05, …

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 …

Plant-Delivered Cholera Toxin B Subunit As An Immunomodulatory Molecule, Takeshi Arakawa

Loma Linda University Electronic Theses, Dissertations & Projects

The B subunit of cholera toxin (CTB) functions as an effective mucosal carrier molecule of chemically or genetically conjugated antigens. Orally delivered CTB or CTB fusion protein binds to G_M1-ganglioside receptor molecules located on cells in the gutassociated lymphoid tissues, the site of immunological induction. We have generated transgenic plants synthesizing CTB conjugated with vaccine antigens for food plant-based prevention of cholera and rotavirus toxin-induced diarrhea and for autoimmune diseases such as insulin-dependent diabetes mellitus (IDDM).

Mice fed with transgenic potato tubers synthesizing 0.3% of CTB as total tuber protein generated serum and mucosal antibodies with toxin neutralizing …

Igf-Ii Expression In Human Tumor Tissues And Human Igf-Ii Ribozyme Action, Zhaodong Xu

Loma Linda University Electronic Theses, Dissertations & Projects

Insulin-like growth factors (IGFs) are potent mitogens for a variety of cancer cells in vitro. In breast, prostate and neuroblastoma cancer cells, it has been suggested that IGF-II plays a paracrine/autocrine role. However, information on cell-type -specific IGF-II expression in vivo is limited. In situ hybridization and immunohistochemistry were carried out to determine the cell type expressing IGF-II in different tumor tissues. Both IGF-II mRNA and protein were localized to malignant cells, and expression in the stroma was minimal in all the tumors. The data are consistent with the hypothesis that cancer cell growth is regulated by IGF-II, and therefore …

The Relationship Between Cobalamin Deficiency And Neurological Dysfunction In Older Adults, Marion Bachra

Loma Linda University Electronic Theses, Dissertations & Projects

The prevalence of cobalamin (Obi) deficiency among older adults is higher than among younger adults, and is estimated to be between 14% and 23%. Persistent Cbl deficiency can cause a variety of neurological deficits. Neurological dysfunction occurs commonly among older adults, raising the research question whether or not there is a relationship between the high prevalence of Cbl deficiency and neurological dysfunction among older adults.

This case-control study enrolled 120 subjects with and without neurological dysfunction through the Faculty Medical Offices' Internal Medicine and Neurology Outpatient Clinics. All subjects received a neurological and cognitive exam. Blood samples were drawn to …

Ventilation Behavior Of The Mantis Shrimp, Hemisquilla Ensigera Californiensis In Hypoxic Burrows, Tamara L. Richter

Loma Linda University Electronic Theses, Dissertations & Projects

The burrow-dwelling mantis shrimp, Hemisquilla ensigera californiensis, is an environmentally challenged marine species due to the fact it inhabits burrows located beneath the surface of the sediment where oxygen pressure is low and easily depleted. This experiment revealed that burrow oxygen pressure (pO₂) is frequently hypoxic and can become anoxic. Average pO₂ within the burrow is between 40-50 mm Hg and may drop below 10 mm Hg even if the burrow isn't capped. When capped, p0₂ rapidly drops to 0 mm Hg within two hours. Low pO₂ does not result in decreased animal activity, …