Nervous System Commons^™

Neuronal Connections From The Cervix To The Spinal Cord Before Parturition, Mary Medina Groves

Loma Linda University Electronic Theses, Dissertations & Projects

By the day before birth, the density of nerve fibers in the cervix has increased compared to earlier in pregnancy or in nonpregnant mice. Similar findings are reported in parturient women. To test the hypothesis that connections between the cervix and spinal cord are enhanced by term, the cervix of nonpregnant and time-dated pregnant mice (day 15 or 18 post-breeding) was injected with pseudorabies virus (PRV), a trans-synaptic retrograde neural tract tracer. Mice were euthanized and perfused 5 days later. The spinal cord and cervix were removed and postfixed overnight, immersed in sucrose, and cryostat sections through the thoracic to …

Radiation-Induced Glutamate Transport Alterations In Neuron-Astrocyte Coupling, Martha Celia Sanchez

Loma Linda University Electronic Theses, Dissertations & Projects

Exposure of the central nervous system (CNS) to ionizing radiation is known to result in behavioral, cognitive, and motor deficits - effects similar to those seen in many neurodegenerative disorders. Neurons and astrocytes, two principal cell types in the brain, coexist as an interdependent metabolic unit via the neurotransmitter glutamate. Disruption of this metabolic coupling would have widespread effects within the CNS, therefore it is hypothesized that ionizing radiation impairs glutamate transport and metabolism, and increases oxidative stress, ultimately impairing neuron-astrocyte coupling. We propose to investigate the mechanism and determine the impetus for radiation-induced neurotoxicity by measuring the temporal sequence …

Is Electrical Stimulation A Predictive Tool For Autonomic Dysfunction In Males With Diabetes?, Susan Dorothy Rand

Loma Linda University Electronic Theses, Dissertations & Projects

The purpose of this study was to examine whether electrical stimulation can be used as a predictive tool to assess autonomic dysfunction in males with diabetes. The study was designed to better understand the extent of autonomic nervous system (ANS) dysfunction in the diabetic population.

Controls and patients with diabetes were recruited from the community at large and the Loma Linda University Diabetes Treatment Center and were managed by a physician. Twelve (12) people with diabetes and thirteen (13) control subjects participated. Mean age (years) for people with diabetes was 52.4 +/- 6.1 and 47.2 +/-11.1 for controls (p =0.05). …

The Role Of Nogo-A During Development Of The Chick Central Nervous System, Shelly A. Caltharp

Loma Linda University Electronic Theses, Dissertations & Projects

Nogo-A is a potent inhibitor of axon regeneration that is expressed by myelin forming oligodendrocytes of the adult central nervous system (CNS). However, neuronal expression of Nogo-A during development suggests an additional role. Little is known about the putative functions of Nogo-A during embryonic development. To examine its potential role we isolated and analyzed the Nogo-A sequence in the chick, we localized its mRNA expression pattern and cell-specific distribution during key phases of cortical development, and studied regulation of its expression during phases that showed promise of function based on expression patterns.

Our results revealed five previously undescribed Nogo-A specific …

Diabetes: The Interrelationship Between Vascular, Nervous Systems And Avandia, Salameh Bweir

Loma Linda University Electronic Theses, Dissertations & Projects

Diabetes Mellitus has been linked to vascular and neurological impairments. The purpose of this study was to assess the relationship between vascular endothelial dysfunction, autonomic and somatic nervous systems impairment in diabetic patients. These studies also evaluated the effects of rosiglitazone (Avandia) on the vascular, autonomic, and somatic nervous systems.

Fourteen diabetic subjects and fourteen control subjects (age matched) participated in three series of experiments. Using Whitney volume plesythmography to assess post occlusion blood flow in the subject’s forearm did assessment of vascular endothelial function. Evaluating skin blood flow, orthostatic tolerance, heart rate, and thermal responses under thermal and postural …

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 …

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 Cytochemical Evaluation Of Blood-Brain Barrier Sodium, Potassium- And Calcium-Adenosine Triphosphatase Polarity, Panya Steve Manoonkitiwongsa

Loma Linda University Electronic Theses, Dissertations & Projects

The blood-brain barrier (BBB) is formed by cerebral vascular endothelial cells. Brain ion and fluid homeotasis essential for proper neural functioning is due to the BBB. Sodium-potassium and calcium-activated adenosine triphosphatase (Na⁺, K⁺-ATPase and Ca²⁺-ATPase) serve as one of the main mechanisms controlling brain Na⁺, K⁺, and Ca²⁺ concentrations. The present accepted concept is that both of these enzymes are localized to the abluminal plasma membrane of endothelial cells although there have been contrary results from some studies. Because of these discrepancies, further work was needed. Various cytochemical procedures …

Reference Serum Chemistry And Hematological Values For Spinal Cord Injured Patients, Michael S. Laymon, Antone L. Davis Ii

Loma Linda University Electronic Theses, Dissertations & Projects

Serum chemistry and hematological values from 220 traumatic spinal cord injured patients (157 male and 63 female between the ages of 15-47, with greater than six months from injury) were compiled via chart review. Traumatic spinal cord injured patient’s reference ranges were determined and compared with the general population reference ranges. Reference ranges within the spinal cord population were compared by age, gender, level of injury and chronicity of injury. The reference ranges determined for all groups within this spinal cord population fall within the reference ranges of the general population. This supports recent research which suggests that a decrease …

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 …

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 …

Neurophysiologic Bases For Abnormal Muscle Coactivation Patterns In Hemiparetic Stroke, Julius P.A. Dewald

Loma Linda University Electronic Theses, Dissertations & Projects

To study disturbed muscle activation patterns in hemiparetic stroke, the EMG activity in spastic-paretic and contralateral elbow muscles of 10 stroke subjects were compared during graded directionally varying voluntary isometric contractions. We observed significant shifts in the peak EMG angle and increases in the angular range of EMG activity in the impaired upper limb. Furthermore, we observed stereotypic coactivation of many muscles acting at the same joint or at different joints across all subjects.

The effect of elbow angle changes on muscle coactivation patterns was studied by examining isometric torque-angle relations under passive and active conditions in 8 stroke subjects. …

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 …

Topographic Development Of The Corticocollicular Projection In The Neonatal Rat, F. Allen Richburg Ii

Loma Linda University Electronic Theses, Dissertations & Projects

The density and distribution of labeled cortical cells was examined following discrete deposits of retrograde tracers into the superior colliculus (SC) of neonatal and adult rats to study the topographic order of SC afferents from the cortex during the initial phase of axon ingrowth. Small deposits of red and green latex microspheres (0.02-0.05ul) were placed into the SC of rats ranging in age from birth to adulthood using glass micropipettes (tip diameter 25-35um). The animals, following a 48hr survival period, were deeply anesthetized and perfused with normal saline followed by a 10% formal-saline solution. The brains were sectioned coronally at …

Age-Related Changes In Meissner Corpuscles Of Diabetic Mice As Observed By Electron Microscopy, Vicky R. Ras

Loma Linda University Electronic Theses, Dissertations & Projects

Light touch and low-frequency vibration sense are often impaired in diabetic patients. Meissner corpuscles are distally located mechanoreceptors that respond to these stimuli. Peripheral sensory neuropathy in diabetes progresses from distal to proximal, therefore, Meissner corpuscles are ideally suited to study diabetic neuropathy in the C57BL/Ks (db/db) mouse.

Corpuscles from the forepaw digital pads of 9 diabetic and 9 nondiabetic littermates were studied by electron microscopy. These were divided into 3 age groups; 2.5 months, 10 months, and 17 months old.

Ultrastructural changes observed within various receptor components were myelin figures, multivesicular bodies, vacuoles, basal lamina duplication, abnormal and enlarged …

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-Related Changes Of Neurites In Meissner Corpuscles Of Diabetic, Vicky R. Ras

Loma Linda University Electronic Theses, Dissertations & Projects

This thesis is based on a qualitative and quantitative study of the neural component of Meissner corpuscles of diabetic and non-diabetic mice. Age-related changes were also documented in these mechanoreceptors. Corpuscles from forty-six diabetic mice and forty-six non-diabetic mice ranging from 2.5 to 17 months old were studied. Forepaw index digital pads were formalin-fixed and frozen-sectioned parallel to each digit and perpendicular to the skin. Serial sections were then silver-impregnated to allow light microscopic examination of the neurites in the corpuscles.

Neurites became more coarse, tortuous, branched, varicose, and thus more complex until middle age. Corpuscle size appeared greatest at …

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 Neural Organization Of The Lamina Ganglionaris In The Crab Hemigrapsus Nudus A Light And Electron Microscope Study, Hsu-Cheng Huang

Loma Linda University Electronic Theses, Dissertations & Projects

The gross structure and the neural arrangements in the optic lamina of crab Hemigrapsus nudus have been studied by light microscopy Golgi techniques and by electron microscopy. The lamina from distal to proximal is composed of a distinct cell layer, a fibular synaptic region, the plexiform layer, a spares cell layer, and the first optic chiasma. Golgi preparation of the lamina reveal four types of cells contributing to the lamina synaptic layer. Retinula cell axons and terminations, monopolar neurons with perikarya in the distal cell layer, tangential cells, neurons whose primary process enters from the chiasma with secondary processes branching …

The Developmental Fine Structure Of Pacinian Corpuscles, Pedro B. Nava

Loma Linda University Electronic Theses, Dissertations & Projects

A preliminary light microscopic study of the mouse hind limb revealed a group of about 20 Pacinian corpuscles extending from the mid-region of the fibula to the tibio-fibular fusion strategically located for the possible sensing of bone-transmitted vibration.

The fine structure of the corpuscles is described in four stages: primordial or prenatal (19 and 20 days); early differentiation (1-8 days postnatal); differentiated corpuscle (9, 10, 12, 14 and 21 days postnatal); and adult (28 days old).

The corpuscles commence development during the 19th prenatal day. The corpuscle then consists of a nerve ending surrounded by sheath-cells which appear to be …

Mandibular Nerve Regeneration Through Solid And Canalized Bone And Plaster Grafts, Lawrence D. Day

Loma Linda University Electronic Theses, Dissertations & Projects

Utilizing an extra-oral approach and sterile technique, left mandibular ostectomy was performed on five miniature pigs. The segment removed was 3 cm long and included the inferior border, mandibular canal and, in some cases, apices of a molar tooth.

Bone and plaster grafts (one solid and one canalized of each) were used to fill these defects. The fifth was left with no graft.

The objective was to learn the effect of each of these procedures on regeneration of the mandibular nerve across the defect. It was hypothesized that canals through the grafts would facilitate regeneration.

X-rays were taken periodically. The …

A Study Of Regeneration Of Peripheral Nerve In The Rat, James C. Jay

Loma Linda University Electronic Theses, Dissertations & Projects

Due to improvements in fixation and embedding techniques a restudy of regenerating peripheral nerve was thought advisable in order to better understand and describe the processes which take place.

Femoral nerves of white Wistar rats were used. The lesions were made by either crushing or severing the nerve. After a period of regeneration, varying from 12 hours to six days, the wound was reopened and the injured portion fixed in situ with 1% osmium tetroxide. The tissues were then removed, dehydrated, embedded and sectioned. The sections were stained and studied with a modified RCA EMU2A electron microscope.

Observations revealed that …