Animal Experimentation and Research Commons^™

Effects Of Chromium On Mouse Splenic T Lymphocytes And Effects Of Ethanol Exposure During Early Neurodevelopment On Behaviors In Mice, Lu Dai

Theses and Dissertations--Toxicology and Cancer Biology

The dissertation consists of three major projects with the focus on the immunotoxicity of chromium and the behavior disorders caused by early ETOH exposure respectively.

Hexavalent chromium [Cr(VI)] is widely used in various industrial processes and has been recognized as a carcinogen. As the first line of host defense system, the immune system can be a primary target of Cr(VI). T cell population represents a major arm of the immune system that plays a critical role in host anti-tumor immunity. Dysfunction of T cells compromises host anti-tumor immunity resulting in oncogenesis. Using mouse splenic T cells as an in vitro …

Age-Dependent Breakdown Of The Blood Brain Barrier And Associated Changes In S100b Ko Mice, Eric V. Brown

Graduate School of Biomedical Sciences Theses and Dissertations

Autoantibodies play an important role in many autoimmune diseases. Recent research has shown that breakdown of the blood brain barrier (BBB) occurs concomitant to generation of brain reactive autoantibodies in many neurodegenerative diseases, which serve as biomarkers and drivers of pathology. SI00B, a calcium binding protein found most highly expressed in astrocytes which ensheathe the BBB, has many functions in neural development and signaling. Currently literature indicates that S100B KO mice develop normally, with no phenotypic abnormalities. Here, it is demonstrated that S100B KO mice seem to develop a chronic BBB breakdown similar to that seen in human neurodegenerative diseases. …

Anti-Inflammatory Effects Of Ppar-Gamma In Surgical Brain Injury (Sbi), Amy Hyong

Loma Linda University Electronic Theses, Dissertations & Projects

Introduction: Brain injury can be caused by neurosurgical procedures themselves, due to direct trauma, retractor stretch, intraoperative hemorrhage and electrocautery damage. As a result of this surgical brain injury (SBI) postoperative complications such as inflammation, brain edema, and cell death can occur in the susceptible brain areas. Cerebral inflammation is a known contributor to the pathophysiology of brain injury. Following brain injury, the release of inflammatory mediators facilitates the development of BBB breakdown, cerebral edema, oxidative stress and neuronal death, resulting in further tissue damage in the brain and poor neurological outcomes. This study evaluates whether the use of a …

Radiation Effects On Dopamine-Mediated Prepulse Inhibition In The C57bl/6 Mouse, Cara Nicole Zuccarelli Miller

Loma Linda University Electronic Theses, Dissertations & Projects

This study examined the effects of proton and gamma radiation on a dopamine-dependent sensory gating mechanism: prepulse inhibition of the startle reflex. The purpose of this research was to describe potential hazards of proton radiation to the central nervous system in long-term space fight and for proton therapy patients. Results from previous research indicate that startle behavior is modified by proton and iron radiation. Forty-eight 10-½ week old, male C57BL/6 mice were used to characterize the optimal parameters for the model (prepulse duration, probe duration, and stimulus-onset-asynchrony). Three hundred and fifty two mice were used to characterize the time course …

Neuronal And Metabolic Increases In Pedunculopontine Nucleus Of Parkinson's Rats, Jonathan Dennis Carlson

Loma Linda University Electronic Theses, Dissertations & Projects

The theoretical mechanisms underlying the symptoms of Parkinson’s disease are based on dysfunctional output from the basal ganglia projected to the cortex via the thalamus. However, the subthalamic nucleus (STN) and substantia nigra pars reticularis (SNr) as part of the basal ganglia, also project to the brainstem, in particular to the pedunculopontine nucleus (PPN). Both the STN and SNr have altered neuronal activity in the 6-hydroxydopamine (6-OHDA) Parkinson’s model rat. Thus, it is hypothesized that the PPN is altered in this model of Parkinson’s disease.

This hypothesis was examined by comparing the rates of glucose metabolism and spontaneous neuronal activity …

Effect Of Age On The Structure Of Meissner Corpuscles In Forepad Digital Pads Of Mice, Roger C. Mathewson

Loma Linda University Electronic Theses, Dissertations & Projects

Meissner corpuscles in forepaw digital pads of albino mice were examined by light and electron microscopy to determine structural age-changes. After 1.5 months of age, no intraepidermal nerve fibers were seen extending from corpuscles. From young (1.5-6 months) to middle age (9-15 months), corpuscles became larger and more complex, gaining more horizontally arranged terminals, associated lamellae and connective tissue. At old age (18-26 months), corpuscles became small and lobulated, appearing disorganized. There was no loosening of the corpuscle-epidermal interface. An increase in collagenous connective tissue and basal lamina duplication occurred with advancing age. Ultrastructural age-changes consisted of disorganization of the …

Regeneration Of Meissner Corpuscles In Diabetic Mice Following Median Nerve Crush, Bonnie J. Forrester

Loma Linda University Electronic Theses, Dissertations & Projects

The hyperglycemic metabolic condition found in diabetes mellitus leads to the development of sensory neuropathies and causes delayed and incomplete neuronal regeneration. Diabetic sensory neuropathy has been shown to contribute to the impairment of light touch and low frequency vibratory perception. It is proposed that the regeneration of receptors that detect these sensations will be delayed and incomplete in diabetic animals with uncontrolled hyperglycemia. This study addresses the effects of diabetes on the regeneration of Meissner corpuscles, distal sensory endings that perceive light touch and low frequency vibration.

Corpuscles from 60 diabetic mice, and their age-matched, non-diabetic littermates, were examined …

A [6-14c] Glucose Autoradiographic Study Of The Rat Brainstem Under Hypercapnic And Hypocapnic Conditions: Identification Of Respiratory-Related Regions, Tobey M. Leung

Loma Linda University Electronic Theses, Dissertations & Projects

The effects of systemic hypercapnia on brainstem metabolism were studied with the [6-¹⁴C] glucose autoradiography method. Neuronal pools which are metabolically active take up more [6-¹⁴C] glucose and maybe revealed pictorially as darker areas on autoradiograms. Since a high concentration of carbon dioxide stimulates central chemoreceptors and hence enhances respiratory drive, the darker regions on the autoradiograms may represent regions concentrated with respiratory-related neurons. Two discrete regions in the ventrolateral medulla (a column near nucleus ambiguus and a column in the lateral reticular nucleus) appeared dark and were analyzed with an image processing system, which converted …

Age-Changes Of The Neuronal Component Of Meissner Corpuscles In The Mouse Digital Pad, Roger C. Mathewson

Loma Linda University Electronic Theses, Dissertations & Projects

Silver impregnated sections of mouse digital pads were studied using light microscopy to detect age-related changes of the neuronal component of Meissner corpuscles. Direct microscopic observation, photomicrographs and camera lucida tracing were utilized. From qualitative observation, the corpuscular neurites were found to undergo morphological age-related changes of diameter, tortuosity, varicosity, branching and terminal expansion size. Quantitative examination was made of the number of corpuscles, corpuscular neurites, branching neurites, cross-innervations, terminal neurite expansions, neurite intraepidermal continuations and terminal axonal processes. The number of corpuscles and neurite intraepidermal continuations decreased with age while having significant linear correlation; whereas, branching increased with age …

The Relationship Between Whole Brain Catecholamine Depletion In Carassius Auratus And The Exposure To Inescapable Shock In A Learned Helplessness Paradigm, Roderick J. Misunis

Masters Theses

Learned helplessness is a psychological concept that describes the subsequent escape-avoidance behavior of experimental subjects who are exposed to uncontrollable stressors. Subjects after treatment are unable to respond in situations where escape is possible. Two major theorists, Seligman and Weiss, have proposed explanations concerning the phenomena. Seligman feels that the subject is unable to respond due to the fact that the exposure to an uncontrollable stressor has caused him to learn to be "helpless". Weiss feels that the inability to respond can best be described by alterations in the subject's brain neurochemistry, specifically the neurotransmitter norepinephrine. This paper is an …