Life Sciences Commons^™

Mechanisms Of Retinal Ganglion Cell Development In The Rhesus Macaque, Thomas C. Steineke

Loma Linda University Electronic Theses, Dissertations & Projects

At present, no effective treatments are known for many common neurological problems. For instance, degenerative diseases and central nervous system injuries are two examples of conditions for which few treatment options exist. Studying how neurons develop, and how they establish and maintain connections may provide important insights into potential treatment modalities. To this end, retinal ganglion cell structural development was studied in the fetal rhesus macaque ranging in age from embryonic day (E)60 to El65 (gestation is 165 ± 2 days). Horse radish peroxidase (HRP) retrograde labeling techniques were used to investigate changes in retinal ganglion cell structure during fetal …

Mechanism Of Action Of Pentobarbital Induced Attenuation Of Vascular Smooth Muscle Contraction, Michael R. Samardzija

Loma Linda University Electronic Theses, Dissertations & Projects

Pentobarbital (PB) vasodilates dog mesenteric and cerebral arteries precontracted with KC1, PGF_2α, caffeine or norepinephrine. It is postulated that PB causes this dilation by reducing Ca²⁺ influx as a non-specific Ca²⁺ channel blocker, or decreasing intracellular Ca²⁺ release. We examined PB effects on intracellular Ca²⁺ release (ICR) and extracellular Ca²⁺ influx (ECI) by stimulating Sprague-Dawley rat tail artery rings with either 100 mM KC1, 50 uM phenylephrine (PE), or two different electrical field stimulation (EES) parameters: tetrodotoxin (TTX; 1 uM) sensitive, or perivascular nerve, (NEFS) stimulation (10 Hz, 0.3 ms, 50 V, 30 …

Transcriptional Regulation Of Insulin-Like Growth Factor : Binding Protein-4 By Protein Kinase A And Protein Kinase C Signal Transduction Pathways In Human Bone Cells, Kuk-Wha Lee

Loma Linda University Electronic Theses, Dissertations & Projects

The Insulin-like Growth Factor (IGF) system is an important local regulator of osteoblast proliferation, the primary determinant of bone formation. Six IGF Binding Proteins (IGFBPs) either inhibit or enhance IGF actions. Previous studies have shown that IGFBP-4 is an important negative regulator of osteoblast cell proliferation and that agents such as PTH which increase intracellular cAMP significantly increase expression of IGFBP-4 at the protein and mRNA levels. The underlying molecular mechanism which accounted for IGFBP-4 expression had not been determined and was the focus of my dissertation. Agents which increase intracellular cAMP rapidly increased IGFBP-4 mRNA levels. Nuclear run-off experiments …

Molecular Studies Of Kpnai And Kpnbi R-M Systems : In Klebsiella Pneumoniae M5a1 And Gm236, Nan Sook Lee

Loma Linda University Electronic Theses, Dissertations & Projects

Two possible type I restriction-modification (R-M) systems, KpnAI and KpnBl, were recognized in Klebsiella pneumoniae strains M5al and GM236, respectively. In this project, four hsdR_KpnAI clones (pNLA1 to pNLA4) were obtained by using an endonuclease expression-selection method. The hsdR_KpnAI gene was identified on a 3.6 kb Sau3Al fragment. To map the gene, the hsdR_KpnAI clone was hybridized to a membrane which contained pulsed-field gel electrophoresed fragments of the chromosome of the strain M5al. The hsdR_KpnAI clone was hybridized to a 19 kb Xbal fragment and a 420 kb Blnl fragment, located …

Stab Wounds To Rat Brains : Demyelination, Remyelination And The Cellular Response, Particularly Of Oligodendrocytes, Xie Dangci

Loma Linda University Electronic Theses, Dissertations & Projects

The present body of knowledge concerning the results of central nervous system injury is incomplete and controversial. The role of oligodendrocytes, the cells involved in phagocytosis, the stages of demyelination, and the evidence for remyelination are of interest. Following stab wounds to rat brain cortex, corpus callosum and hippocampus, the animals were examined at 4,7,11,18,23,29,45,60 and 70 days postoperation (dpo). To help in the identification of cells immunocytochemical markers for astrocytes and immature oligodendrocytes were used. These were labels for glial fibrillary acidic protein (GFAP) and myelin/oligodendrocyte specific protein (MOSP) respectively. Light and electron microscopy were correlated using conventionally prepared …

The Relationship Of Dietary And Lifestyle Factors To Bone Mineral Density Of Healthy Singaporean Chinese Women, Ampai Dana Aimsiri

Loma Linda University Electronic Theses, Dissertations & Projects

Few studies have examined the risk factors associated with reduced bone mass in Asians, but none specifically investigated Singaporean Chinese women. The subjects in this study were 16 premenopausal, 8 perimenopausal and 13 postmenopausal women who participated in a larger study which began in 1986. Bone density was measured in 1986 and 1992. Dietary and lifestyle data were collected for this study by personal interview. Association between dietary and lifestyle factors and bone density variables and change in bone density at the end of the 6 year period were assessed by univariate regression analyses.

Postmenopausal women had significantly lower baseline …

Effects Of Furosemide And Oleic Acid On Thyroxine Binding To Isolated Pairs Of Thyroxine Binding Serum Proteins, Deborah Hustead

Loma Linda University Electronic Theses, Dissertations & Projects

Dosage dependent binding inhibition and redistribution of thyroxine (T₄) between three pairs of thyroxine binding serum proteins, TBG-TTR, TBG-albumin and TTR-albumin, by furosemide (0.0 to 1.0 mol/L) and oleic acid (0.0 to 0.10 mol/L) were studied using equilibrium dialysis with purified binding proteins at concentrations 1/200 of levels in normal human sera, separated across the dialysis membrane and competing for T₄.

Furosemide (1.0 mol/L) reduced TBG bound T₄ in both the TBG-TTR system and TBG-albumin system (>90% decrease) and inhibited T₄ binding to TTR in the TTR-albumin system (68% decrease) and to albumin …

The Production And Characterization Of A Monoclonal Antibody To A Naturally Occurring Aminomalonic Acid Epitope And A Comparison With An Antibody To A Synthetically Derived Aminomalonic Acid Epitope, James L. Gulley

Loma Linda University Electronic Theses, Dissertations & Projects

The goal for this project is to undertake the first step in the study of blocking metastasis by a monoclonal antibody. The long range goal of this line of research is to study a novel mechanism for the blocking of tumor metastasis in general and prostatic cancer metastasis in particular. The problem that this addresses is the growing number of cases of prostatic cancer in the increasingly aging male population. This cancer is not lethal unless it metastasizes, yet there is no cure for the metastatic disease. The inherent specificity of a monoclonal antibody combined with the uniqueness of the …

Short And Long Term Effects Of Proton Microbeam Irradiation : In The Lateral Geniculate Nucleus Of Felis Domesticus, Chad Sherwood Reder

Loma Linda University Electronic Theses, Dissertations & Projects

Little is known of the effects of proton irradiation on neural tissue. A 1.0 mm microbeam was used on the cat lateral geniculate nucleus (LGN) to quantify the short term (< 3 months) and long term (< 9 months) effects of radiation damage. The LGN is a large structure with well defined afferent, efferent, and receptive field properties.

Electrophysiological and histological techniques were used to examine the effects of the microbeam at 60, 40, and 16 Gy, administered as a single bolus. Recordings of light evoked responses in the LGN were obtained using microelectrodes in nine animals within 12 weeks of irradiation, and 6 animals within 36 weeks of irradiation. Receptive fields were mapped onto a tangent screen using standard receptive field techniques. Histological measures included afferent …

Cerebral Microcirculatory Effects Of Maturation, Scott R. Elliott

Loma Linda University Electronic Theses, Dissertations & Projects

The present studies demonstrate that in the second (2B) and fourth (4B) branches of newborn and adult sheep middle cerebral arteries, 5-HT2 serotonergic receptors mediate contractile responses to serotonin and that alpha-1 adrenergic receptors mediate contractile responses to norepinephrine. In addition, tissue sensitivity to 5-HT and NE decreases significantly with maturation, but does not vary with branch order. These age-related changes were associated with a decrease in affinity and maximum response in 2B and 4B segments of 5-HT and NE contracted arteries, respectively. Norepinephrine and 5-HT occupancy at the pD₂ rose significantly in 2B segments, but did not change …

Militarywide Survey Of Whole-Grain Food Products And Total Dietary Fiber Analysis Of The Military Ration, John Paul Warber

Loma Linda University Electronic Theses, Dissertations & Projects

Numerous scientific bodies have made the recommendation to increase consumption of whole-grain breads and cereals. This study used a telephone survey to assess the availability of whole-grain foods in a random selection of 109 military installations and 30 military hospitals. Surveyed installations represent over 70% of the active duty military population assigned in the continental United States.

Military food service specialists were asked questions regarding the availability of the following whole-grain products: bread, rolls, buns, flour, pancake mix, brown rice, and ready-to-eat cereals (RTE). They were then asked to read the product ingredient list to validate their perceptions. Perceived availability …

Healing Potential Of Osteotomies Of The Nasal Sinus In The Dog, Roderick W. Tataryn

Loma Linda University Electronic Theses, Dissertations & Projects

Maxillary sinus osteotomy is sometimes indicated for transantral surgical approaches to palatal roots of maxillary molars. A search of the literature showed an absence of any report on the healing potential of such defects. The purpose of this study was to determine histologically the reparative process of the nasal sinus of dogs following small and large surgical antral perforations. After anesthetizing six beagle dogs, full thickness periosteal flaps were raised overlying the maxillary buccal cortical plates. A 5x5 mm diameter perforation was created with a trephine bur above the second maxillary premolar on one side of each animal. On the …

Measurement Of Blood Flow In Reflected Muco-Gingival Tissue Flaps In Cats : Using The Radiolabeled Microsphere Method, Gary T. Wuchenrich

Loma Linda University Electronic Theses, Dissertations & Projects

Blood flow to the maxilla and mandible may vary due to differences in vascular supply and in physiologic, metabolic and pathologic conditions. In general it is accepted that oral tissues have an abundant blood supply; however, there is little information quantifying blood flow to these regions. In this study, the maxillary tissues were chosen to measure the blood flow in attached and reflected gingival tissue in adult cats using the radiolabeled microsphere method.

Sixteen cats with permanent dentition, clean mouths, and without inflamed gingiva upon visual inspection were used and divided into two groups. Group 1 consisted of six cats …

Mechanism Of Mitogenic Action Of Aluminum Ion On Bone Cells : Potential Involvement Of The Insulin-Like Growth Factor Regulatory System, Aera Yoo

Loma Linda University Electronic Theses, Dissertations & Projects

Micromolar concentrations of aluminum ion (oxidation state of 3 +) consistently stimulated [3H]thymidine incorporation into cell DNA and increased cellular alkaline phosphatase activity (an osteoblastic differentiation marker) in osteoblast-like cells of chicken and human origin. Although biphasic, dose-dependent stimulations were highly reproducible, the maximal stimulatory dose varied among different experiments. Mitogenic doses of aluminum ion also stimulated collagen synthesis in cultured human osteosarcoma TE85 cells. In addition, the same mitogenic concentrations of aluminum ion enhanced the 1,25 dihydroxy vitamin D3-dependent stimulation of osteocalcin secretion. Together, these findings indicate that aluminum at micromolar concentrations, stimulates the proliferation, differentiation, and activity of …

Periodontal Repair In Dogs : Part I : Evaluation Of The Natural Disease Model ; Part Ii : Eptfe Barrier Membranes Support Wound Stabilization And Enhance Bone Regeneration, James Marc Haney

Loma Linda University Electronic Theses, Dissertations & Projects

Animal models are frequently consulted for histometric analysis of reconstructive periodontal therapy. Statistical analysis of induced lesion defects and surgically created defects from our laboratory suggest defect size homogeneity is critical for the model to discriminate treatment effects. This study characterizes natural disease defects in beagle dogs. Buccal-lingual histologic sections from the 2nd, 3rd, and 4th mandibular premolar teeth (P2, P3, P4) from 6 aged beagle dogs with natural disease defects were evaluated for variation in defect height between pair matched tooth types, and jaw quadrants, as well as estimated confidence intervals for treatment differences between left and right pair …

Signal Transduction In Bacterial Chemotaxis, Edward Heath Rowsell

Loma Linda University Electronic Theses, Dissertations & Projects

This study investigated the site of ATP utilization in the signal transduction pathway of bacterial chemotaxis and localized the point of convergence of a methylation-independent system of chemotaxis with the methylation-dependent system. The identity of the signal originating from the phosphotransferase system was investigated by substituting the fructose-inducible HPr-like protein FPr for HPr in transport and chemotaxis. In addition, a novel chemoattractant, glycerol, was identified for Salmonella typhimurium. Histidine-auxotrophic S. typhimurium strains ST23 (hisF) and ST171 (hisF cheB) were depleted for ATP. The times required for the bacteria to adapt to a step increase in serine, …

An Intramural, Tension-Modulating Reflex In The Rat Caudal Artery, Greg G. Geary

Loma Linda University Electronic Theses, Dissertations & Projects

Electrical field stimulation (EES) of preconstricted arteries causes relaxation. This relaxation is of either neuronal, vascular smooth muscle, and/or endothelial origins. We have shown that EFS-induced relaxation of intact, phenylephrine (PE) preconstricted rat tail artery (RTA) rings was dependent upon the extracellular concentration of Ca++. Inhibiting either nitric oxide (NO) synthesis with N-nitro-L-arginine methyl ester (L-NAME), or the synthesis of cyclic guanosine monophosphate (cGMP) with methylene blue (MB) reduced the EFS-induced relaxation. In addition, inhibition of K_Ca++-dependent hyperpolarization with tetraethylammonium (TEA), or K_ATP hyperpolarization with BaCl₂ or glibenclamide also reduced EFS-induced relaxation. L-arginine reversed the effect …

The Invariant Arginine In Motif 2 Of Escherichia Coli Alanyl-Trna Synthetase : Is Important For Catalysis But Not For Substrate Binding, Ying Lu

Loma Linda University Electronic Theses, Dissertations & Projects

Structural motifs 2 and 3, located in the active site of class II aminoacyl-tRNA synthetases, each contain an invariant arginine thought to participate in interactions with ATP. For Escherichia coli alanyl-tRNA synthetase (AlaRS), sequence comparisons indicate that Arg69 should be aligned with the invariant arginine in motif 2 of other class II synthetases. Site-directed random mutagenesis has been employed to generate a set of proteins containing amino acid substitutions in a portion of motif 2 of AlaRS. In this set, only mutations at position 69 caused the enzyme to lose ability to complement growth of an alaS deletion strain, …

Inhibition Of Nnk Mutagenesis And Metabolism By Chemopreventive Phytochemicals, Cecil Henry Miller

Loma Linda University Electronic Theses, Dissertations & Projects

Approximately one third of all cancer deaths in the United States can be linked to the use of tobacco products. Cessation of smoking is not always an effective prevention method, especially since nicotine is so addictive. For those individuals who continue to use tobacco products, chemoprevention may be an alternative to reduce their cancer risk. We have investigated the chemopreventive efficacy of five phenolic (catechin, ellagic acid, escletin, esculin and propyl gallate) and five non-phenolic (capsaicin, silymarin, diallyl sulfide, tannic acid, and d-limonene) phytochemicals on tobacco-specific nitrosamine (NNK)-induced mutagenesis and NNK metabolism. In the mutagenesis studies, Salmonella typhimuriumstrain TA1535 …

The Influence Of Prepregnancy Weight And Maternal Weight Gain : On Birth Weight Among Black Wic Participants In San Bernardino County, Marta Lukas Sovyanhadi

Loma Linda University Electronic Theses, Dissertations & Projects

Birth records show that San Bernardino County has the highest black infant mortality rate of the 16 counties in California with the largest proportion of African-Americans births. Although total infant deaths in San Bernardino County had fallen to 8.6 per 1,000 live births by 1992, the infant mortality rate among the black population of the county was close to two times higher at 16.8 per 1,000. This is the first study to address the high infant mortality rate among blacks in San Bernardino County. Factors which may affect the black infant mortality rate were examined.

Subjects were drawn from a …

A Physical Map Of The Klebsiella Pneumoniae M5a1 Genome, Alexandrine Randriamahefa

Loma Linda University Electronic Theses, Dissertations & Projects

Klebsiella pneumoniae is an enteric opportunistic pathogen which commonly causes pulmonary, urinary tract and kidney infections. It has also been widely used for the study of nitrogen fixation. In this study, a macrorestriction map of K. pneumoniae M5a1 chromosomal DNA was constructed using pulsed field gel electrophoresis (PFGE) and Southern hybridization techniques. The genome DNA was digested with two rare cutting restriction enzymes (XbaI and BlnI) and the genome size was estimated from the sum of the fragment sizes as 5,121 Kb (+2.8%). A tentative order of fragments was deduced using Southern hybridization with purified restriction fragments. …