Life Sciences Commons^™

The Effects Of Temperature On The Physiology Of Phataria Unifascialis : And Its Implications For The Species' Distribution In The Gulf Of California, Michael Boyce Morgan

Loma Linda University Electronic Theses, Dissertations & Projects

Populations of the asteroid Phataria unifascialis were sampled subtidally in the Gulf of California at Loreto, well within the species' distribution, and at Bahia de los Angeles (the Bay of LA), at the northern end of its distribution on several occasions between 1989 and 1991 to determine the influence of water temperature on species' physiology at each location. The starfish was much more abundant at Loreto, and though both locations had similar indices of pyloric caeca and gonad development, the population at Loreto was distinctly separated by depth into a shallow reproducing population and a deeper feeding population. No such …

Plasticity Of The Gnrh Neuronal System During Sexual Maturation Of The Male Djungarian Hamster, Kevin L. Buchanan

Loma Linda University Electronic Theses, Dissertations & Projects

Onset of puberty in male Djungarian hamsters is characterized by increased pituitary gonadotropin secretion and testes maturation, and is controlled by neurons within the brain which secrete gonadotropin-releasing hormone (GnRH). Puberty is associated with increased numbers of morphologically unipolar, but not bipolar, GnRH neurons in the medial preoptic area (MPOA) and diagonal band of Broca (DBB). To test the hypothesis that delayed sexual maturation arrests this increase, males were exposed to short days or administered melatonin. Males with delayed puberty had significantly fewer unipolar GnRH neuron numbers in the MPOA and DBB comparable to pubertal controls in long days. Unipolar …

Cortisol In The Ovine Fetus : Its Regulation And Role In Parturition, Ede Marie Apostolakis

Loma Linda University Electronic Theses, Dissertations & Projects

In fetal sheep, circulating cortisol increase during late gestation to abruptly rise 72 hours preceding birth. Although the surge in cortisol is thought to initiate the endocrine cascade which triggers parturition, it is not known what drives the prepartum rise in fetal cortisol. The first study tested the hypothesis that basal cortisol secretion is regulated by adrenocorticotropin (ACTH) which in turn, is controlled by arginine vasopressin (AVP). The fetus challenged with AVP increased plasma ACTH and cortisol concentrations. Pretreatment with an AVP V₁ receptor antagonist blocked AVP-induced plasma ACTH cortisol but failed to alter basal ACTH or cortisol. To …

An Evaluation Of Surface Enamel Damage Following The Debonding Of Ceramic Brackets : A Follow-Up Study, B. Scott Hood

Loma Linda University Electronic Theses, Dissertations & Projects

To evaluate surface enamel damage after debonding ceramic brackets using their manufacturer's recommended methods, sixty four bicuspid teeth were bonded with three different types of ceramic brackets and one type of metal bracket. All the brackets tested utilized mechanical retention only. The brackets were debonded in the mouth seven to ten days after bonding, extracted and evaluated with a scanning electron microscope. The study concluded that: 1) all brackets alter the surface enamel, 2) there is a significant difference in surface enamel damage between the metal bracket and the ceramic brackets utilizing a tensile debonding method, 3) there is no …

New In Vivo And In Vitro Techniques For Quantification Of Lateral Force Levels That Cause Implants To Fail : A Progress Report On Monkey Research, V. Leroy Leggitt

Loma Linda University Electronic Theses, Dissertations & Projects

Two new techniques for quantification of forces generated by an expansion screw apparatus placed between pairs of cylindrical endosseous titanium implants are described, along with preliminary data gained from their use in Macaca rhesus monkeys. Strain gages were bonded to the expansion apparatus and were calibrated either directly by micro load cell, or indirectly by Instron Machine to reflect the applied force.

Immediate loads of up to 6 kilograms have been applied to the implants with no increase in mobility as verified by a Periotest device. No previous studies on the orthodontic uses of implants have evaluated in vivo forces …

Characterization Of Murine Interleukin-4 (Il-4) : Biological Activities And Initial Identification Of Signal Transduction Mechanisms In Il-4-Mediated Macrophage Activation, Henkie Pierre Tan

Loma Linda University Electronic Theses, Dissertations & Projects

IL-4, in the presence of macrophages (MΦs), has previously been demonstrated to be tumoricidal in vitro and in vivo, possibly through MΦ activation. In the current study, the biological activities of murine IL-4 on MΦs, and the initial identification of signal transduction mechanisms in IL-4-mediated MΦ activation were determined. Hamster MΦ were activated with IL-4 to study MΦ tumoricidal activity against hamster pancreatic adenocarcinoma in vivo.Through this initial study, it was observed that murine IL-4 is species specific and incapable of crossing the narrow phylogenetic barrier to hamster and perhaps rat (partially). The effects of murine IL-4 on allogeneic …

The Effect Of Electrical Stimulation Of The Dorsal Raphe Nucleus On Local Cerebral Glucose Metabolism And Epileptogenesis In The Rat, Clifford C. Douglas

Loma Linda University Electronic Theses, Dissertations & Projects

Anatomic connections between the dorsal raphé and the hippocampus have been described in the literature; however, the understanding of the functional importance of these connections is not complete. In these studies the "functional" raphé-hippocampal pathway was elucidated first by the 2-deoxy-d-glucose (2-DG) method, and second by the effect of dorsal raphé electrical stimulation on kindled seizure in the rat. In the 2-DG study, differences in local rates of cerebral glucose metabolism were quantified. The pattern of 2-DG uptake differed significantly from controls (animals with electrodes placed and not receiving an electrical stimulus) and subjects stimulated in the pontine oral reticular …

Modulation Of Rat Hepatic S9-Dependent Mutagenesis, Dna Binding, And Metabolism Of Aflatoxin B1 And Benzo[A]Pyrene By Four Chinese Medicinal Herbs, Brian Yuen Yau Wong

Loma Linda University Electronic Theses, Dissertations & Projects

Extracts of the herbs Oldenlandia diffusa (OD) and Scutellaria barbata (SB) have been used in traditional Chinese medicine for treating liver, lung and rectal tumors while extracts of Astragalus membranaceus (AM) and Ligustrum lucidum (LL) are often used as adjuncts in cancer therapy. In this study, we determined the effects of aqueous extracts of these four herbs on aflatoxin B₁ (AFB₁) benzo[a]pyrene (BaP), benzo[a]pyrene 7,8-dihydrodiol (BaP 7,8-DHD) and benzo[a]pyrene 7,8-dihydrodiol-9,10-epoxide (BPDE)-induced mutagenesis, mediated by enzymes in rat hepatic 9000 x g supernatant (S9), in Salmonella typhimurium TA100. We also studied the effects of these four herbs on …

The Suburban Rice Farmers: Economic And Cultural Change In Japan, Makoto Chiwaki

Masters Theses

The world economic situation is forcing the Japanese government to initiate policies designed to make its rice farming industry more competitive on the world market. These new policies, along with the growth of Japan's urban areas, are causing certain stresses on the cultural institution called bunke among the part-time rice farmers in the Kaizuka region of Chiba City, Japan.

An ethnographic study of these farmers reveals that the farmers of the Kaizuka region have responded to recent changes differently from the farmers of other regions because of their cultural institutions and traditions.

Brainstem Auditory Evoked Potentials In Anuran Amphibians, Marc Brandon Carey

Dissertations and Theses

In this study, I looked at the effects of sound level, temperature and dehydration/hypernatremia on the brainstem auditory evoked potential (BAEP) of four species of anuran amphibians (Rana pipiens, Rana catesbeiana, Bufo americanus and Bufo terrestris). The BAEP was used because it allowed me to monitor both the peripheral and central aspects of auditory nervous function simultaneously and over a long period of time.

The Behavioral Responses Of Utah Prairie Dogs (Cynomys Parvidens) To Translocation, Steven H. Ackers

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In cases where refuge acquisition or captive breeding programs are not practical or justifiable, wild caught animals are frequently translocated into areas of suitable habitat. Such management programs seldom are designed to account for the behavioral responses of translocated animals to an unfamiliar habitat, breakup of social units, and/or interactions with existing social units in the new habitat. Ongoing efforts to translocate threatened Utah prairie dogs (Cynomys parvidens) from areas where conflicts with other land uses are occurring to public land sites have met with limited success. This could be due, in part, to behavioral responses associated with …

Characterization Of Pigments Responsible For Red Or Pink Discoloration In Cooked Pork, Viswasrao M. Ghorpade

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The pigments responsible for pink or red discoloration in cooked vacuum-packaged meat products {bratwurst (pork and beef), ground pork, and pork roasts} were investigated. In bratwurst, this study attempted to characterize the red pigment that appears upon refrigerated storage, and to determine the effect of pH, cooking and storage temperature, and sodium lactate on incidence of red discoloration. Myoglobin was identified in the exudate of samples with red discoloration. Myoglobin levels of cooked products were significantly lower in samples of low initial pH (5.5) or cooked to higher than normal internal temperature (74°C). Red discoloration was associated with microbial growth. …

Effect Of Feeding A Viable Yeast Culture With Or Without Aspergillus Oryzae On Milk Production, Apparent Nutrient Digestibility, Ruminal Fermentation, And Nutrient Degradability In Holstein Cows, Daeyoon Kim

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Twenty-four early to midlactation Holstein cows were allocated to one of three treatments. Treatments consisted of: 1) basal ration plus 60 g wheat bran per day per head (control); 2) basal ration plus 57 g yeast culture per day per head; 3) basal ration plus 57 g yeast culture plus 3 g Aspergillus oryzae per day per head. Feed intake and milk yield were recoreded daily and milk composition and body weights were recorded weekly. Feed and fecal samples were recorded weekly. Feed and fecal samples were collected to determine apparent nutrient digestibility. No statistical difference was observed in milk …

The Heart Rate Responses Of Dairy Cows To Two Types Of Disturbances--Transportation And Aircraft Noises, Hoon M. Ahn

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Three experiments were conducted using implanted heart rate (HR) transmitters. In the first experiment three lactating Holstein cows' HR signals were monitored telemetrically for three successive days under the normal herd management. Overall mean and standard error for these cows was 76.1 ± 0.46 bpm. In the second experiment the same three cows' HR signals were monitored with a portable computer and receiver. The cows were transported 400 kilometers one way over various road surface conditions. The HR signals were monitored consecutively at the beginning of the trip and at hourly intervals during travel. The cows stayed overnight and were …

The Effects Of Feeding A High Level Of Rumen Protected Fat With Rumen Undegradable Protein With Or Without Niacin On Rumen Fermentation Characteristics, Apparent Nutrient Digestibility, And Milk Production In The Early To Mid Lactation Holstein Cow, Carlos Eduardo Batallas

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Forty high producing early to mid lactation Holstein cows were blocked according to stage of lactation and previous two-week milk yield (experiment 1). Eight ruminally and duodenally cannulated nonlactating Holstein cows were used for experiment 2. The objective was to determine the effects of the ration's high fat content (11.53%) when rumen degradable or rumen undegradable protein is fed with or without added niacin. Cows received one of five treatments: 1) basal ration (TMR); 2) basal ration with added rumen undegradable fat (RUF) (1.6 kg); soybean meal (SBM) (1.73 kg), and niacin (12 g); 3) same as treatment 2, without …

Wheat Kernel Hormone Levels During Development And Their Relevance To Zygotic And Somatic Embryogenesis, J. Richard Hess

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Wheat (Triticum aestivum L.) zygotic embryogenesis occurs in a dynamically regulated ovular environment, and in ovulo hormones regulate embryogenic processes. Levels of ABA, IAA, and the cytokinins Z, ZR, DHZ, DHZR, iP, and iPA were studied in developing wheat kernels from anthesis to maturity. High cytokinin and low IAA and ABA levels were associated with the early stage of embryo formation and active tissue histodifferentiation. Following histodifferentiation, cytokinin levels declined while IAA accumulated throughout the stage of active grain growth and then declined with grain maturity. ABA levels increased at the soft-dough developmental stage and through to grain maturity. …

Interactions Between Populations Of Intermediate Wheatgrass And Western Wheatgrass As Influenced By Short-Duration Grazing And Moisture Availability, Gerrit B. Bartels

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The effects of grazing and moisture availability on the competitive interactions of intermediate wheatgrass (Thinopyrum intermedium (Host) Barkw. & D.R. Dewey) and western wheatgrass (Pascopyrum smithii (Rhydb.) A. Love) were examined under a short-duration grazing system in central Utah. The fate of tiller cohorts was observed at approximately monthly intervals at the interface between patches of these two rhizomatous grasses and in monospecific stands. The effects of short-duration grazing, clipping of western wheatgrass following grazing to achieve levels of utilization equivalent to that of intermediate wheatgrass, irrigation, and removal of the competitor were assessed in terms of the …

Influence Of 2,5-Hexanedione, Acrylamide, Tri-O-Tolyl Phosphate, Leptophos And Methylmercury On Endogenous Levels Of Tryptophan, Serotonin And 5-Hydroxyindoleacetic Acid And Serotonin Turnover Rates In Rat Brain, Craig H. Farr

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Several industrial and environmental chemicals cause distal and/or central neuropathy among other diverse toxic effects. Spague-Dawley derived rats were fed doses of 2,5-hexanedione, acrylamide, tri-o-tolyl phosphate, Leptophos and methylmercury via gavage. The dose levels and administration periods were established in previous experiments designed to assess clinical neuropathy using rats trained to walk on a rotorod apparatus fitted with an electrode floor. After intravenous injections of ³H-Tryptophan, whole rat brain homogenates were analyzed using liquid scintillation and spectrofluorometric techniques for levels of tryptophan, serotonin and 5-hydroxyindoleacetic acid. Serotonin turnover rates were calculated using the specific activities of tryptophan and serotonin …

A New Method For Measuring Macroparticulate Systems Applied To Measuring Syneresis Of Renneted Milk Gels, Jonathan R. Maynes

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Syneresis is an integral part of cheese manufacture. The rate and extent of syneresis affect the properties of cheese. There are many factors that affect syneresis, but measured results vary because of inaccuracies in measuring techniques. To better control syneresis, an accurate mathematical description must be developed. Current mathematical models describing syneresis are limited because of inherent error in measuring techniques used to develop them. Developing an accurate model requires an accurate way to measure syneresis.

The curd becomes a particle in a whey suspension when the coagulum is cut. The most effective technique to measure particle size, without interference, …

Effect Of Various Growth-Promoting Factors On Preimplantation Bovine Embryo Development In Vitro, Mark Randall Flood

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The purpose of this research was to define the effects of various growth-promoting factors on in vitro embryonic development of in vitro matured and in vitro fertilized bovine embryos. The control medium was a chemically defined medium which improves the possibility of closely determining the in vivo conditions the embryo is actually exposed to. The growth-promoting factors tested in this experiment included transferrin, IGF-I (insulin-like growth factor-one), IGF-II (insulin-like growth factor-two), TGF-𝛼 (transforming growth factor-alpha), TGF-𝛽1 (transforming growth factor-beta1), PDGF (platelet derived growth factor), EGF (epidermal growth factor), NGF (nerve growth factor), and bFGF (basic fibroblast growth factor). Transferrin was …

Desert Bighorn Sheep And Riverboat Interactions In Cataract Canyon, Utah, Mark C. Stanger

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

I studied desert bighorn sheep (Ovis canadensis nelsoni) behavior and habitat use in response to boating activities during 1985. The percent of total observed time in attention behavior before the boating season, during the boating season, and while riverboats were< 0.8 km from bighorn sheep groups was 1, 1.4, and 12.2, respectively. Estimated energy expenditure did not significantly differ for high riverboat pressures (2 > 0.2) or seasonal comparisons (2 > 0.1). Habitat use significantly differed for proximity to the river, which was probably related to the summer use of the river for drinking. Moderate, minor, and no responses to passing riverboats were observed 3, 39, and 58%, respectively. Responses to riverboats did not significantly differ according to time of day (2 > 0.15) or …

Ecological Implications Of Flavor Generalization By Sheep: Role Of Flavor Intensity And Variation In Toxin Dose, Karen L. Launchbaugh

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Researchers studying diet selection of ungulate herbivores have generally considered plant palatability independent of animals' dietary history. However, more recent studies demonstrate that experiences within the life of an animal strongly influence plant selection. We are beginning to understand how food preferences and aversions are formed through gastro-intestinal feedback. My research specifically examines factors that influence the formation of conditioned flavor aversions in the generalist herbivore, sheep.

I first examined how variability of food toxicity affects the intake of those foods. I determined that sheep apparently have several mechanisms for regulating intake of toxic foods regardless of whether or not …

Circulating Antibodies To Thymic Antigens In Autism And Alzheimer's Disease, Chih-Li Chen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Abnormal T lymphocyte reactions in both autism and Alzheimer's disease (AD) have been reported. This research investigated the possibility that these abnormalities may involve circulating antithymic antibodies. Plasma samples from autistic patients, AD patients, and normal-matched controls were tested for reactivity against murine thymocytes.

In the first of 3 studies results of the enzyme-linked immunosorbent assay (ELISA) were statistically significant for binding (P < 0.001) between antithymic antibodies in plasmas of AD patients and murine thymocytes. Binding (P < 0.05) in low dilutions (1/2.5 and 1/5} of autistic patient plasmas was also observed. In the second study, plasmas of neither autistic nor AD patients significantly inhibited DNA synthesis of thymic cells in the presence of interleukin-1 (IL-l} and phytohemagglutinin (PHA). In the third study, no significant increases (P > 0.05) in cytotoxic activities were detected using AD patient plasmas and both untreated and heat-treated autistic patient plasmas. After further testing, these heat-treated plasmas diluted 1/64 and 1/128 had increased cytotoxicities (P < 0.05) when rabbit complement was added, an indication that cytotoxicity of antithymic antibodies is complement dependent.

Therefore, circulating antithymic antibodies may …

Mobilization Of Iron Enhances The Iron-Dependent Biochemical Reactivity Of Asbestos In Vitro And Contributes To The Cytotoxicity Of Asbestos In Cultured Cells, Loren Glen Lund

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Asbestos related research began approximately 60 years ago, yet, the mechanism(s) by which asbestos exerts its biological effects is not well understood. The hypothesis upon which this dissertation is based is that mobilization of iron from asbestos enhances the iron-dependent biochemical reactivity of asbestos in vitro and contributes to asbestos-dependent cytotoxicity. The specific aims for this hypothesis were, 1) to determine whether iron was responsible for the biochemical reactivity of asbestos in vitro and asbestos-induced cytotoxicity in cultured cells, and 2) to determine whether mobilization of iron from asbestos enhanced the reactions catalyzed by asbestos in vitro and contributes to …

Optimization Of Ranch Management Alternatives In Utah, Scott G. Evans

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The purpose of this study was to determine the optimum combination of various cattle production, range forage, and crop harvesting alternatives available to ranch owners and managers in Utah. While many promising alternatives are available, determining which alternatives to implement is difficult because the total ranch operation must be considered.

Linear programming (LP) is a tool available to ranch managers which allows the profit maximizing combination of improvements to be easily determined. LP allows ranchers to examine the entire ranch operation and to reduce the amount of risk and uncertainty involved in the decision making process.

The typical Utah ranch …

Marten Use Of Subnivean Access Points In Yellowstone National Park, Wyoming, Stuart Scott Sherburne

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Subnivean prey appeared to be the primary reason for subnivean access point use by martens. A logistic regression was used to create a predictive model for differential access point use. Prey biomass in grams and percent ground cover of coarse woody debris (CWD) were used as variables in the model. Goodness of fit of the multivariate model was 0.216; biomass was significant al p = 0.0003, CWD was significant at p = 0.0718. Mean values for prey biomass at used and unused access points were 174.2 g and 81 g, respectively, while mean values of CWD were 24.7% and 18.5%, …

Relationships Among Birds, Willows, And Native Ungulates In And Around Northern Yellowstone National Park, Sally Graves Jackson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Although the impacts of livestock and human activities on riparian zones and associated wildlife have been well documented, little is known about the impacts that browsing by large native ungulates such as elk and moose may have. In the northern Yellowstone area, some willow stands experience intense browsing by elk and moose whereas others experience medium or very low amounts of browsing. The objectives of this study were (1) to compare the species and densities of birds among willow stands that have experienced different intensities of browsing by native ungulates, (2) to measure the relationship between five species of birds …

Genetics And Applications Of Nisin Production In Lactococcus Lactis Subsp. Lactis And Conjugal Exchange Of This Trait, Jeffery R. Broadbent

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Chapter I reviews current literature on gene transfer systems in lactic acid bacteria, how genetically altered microorganisms for food are presently regulated, and how nisin is used as a food preservative.

Chapter II investigates previous reports which linked genes for nisin biosynthesis and sucrose utilization (Nip⁺Suc⁺) to plasmid DNA in two well characterized L. lactis subsp. lactis strains. Plasmid curing studies, conjugations, and DNA-DNA hybridizations indicated that these genes were encoded by chromosomal loci in all Nip⁺Suc⁺ strains examined. Similar results were noted in nisin-sucrose transconjugants of L. lactis subsp. cremoris and S. …

Effects Of Rumen Protein Degradability On Rumen Characteristics, Milk Production And Reproductive Performance In Holstein Dairy Cows, Mario Raul Figueroa

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Three non-lactating Holstein cows fitted with rumen cannula were used to determine crude protein and dry matter rate of disappearance of two protein supplements: 1) soybean meal and 2) bypass protein blend by using the in situ bag technique. Rate disappearance (%/hr) was higher for soybean meal. Two collection periods were completed using 6 cows with a minimum of 21 d adaptation to the treatment top dressed on to the total mixed ration. Ruminal concentration of ammonia N, blood ammonia, and urea did not differ between treatments. Total concentration of volatile fatty acids was higher for bypass protein blend-fed cattle …

Use Of The Polymerase Chain Reaction In The Detection Of Bovine Leukosis, Emma Jane Kelly

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A diagnostic test for bovine leukosis was developed using the polymerase chain reaction (PCR) to amplify a 375 base pair region in the gag gene of the proviral genome.

Blood samples were collected from 3 adult Holstein cows shown to be infected with bovine leukosis virus (BLV) by the agar-gel immunodiffusion (AGID) technique. The 3 samples were mixed and the composite blood was used to inoculate 10 cows. Five of the cows were inoculated with 0.1 ml of blood, and the other cows were inoculated with 1 ml of blood. Five of the cows were negative for BLV by AGID …