Research Methods in Life Sciences Commons^™

Mechanisms Of Hbo-Induced Neuroprotection In A Neonatal Hypoxia-Ischemia Model, John Winter Calvert

Loma Linda University Electronic Theses, Dissertations & Projects

With an incidence approaching 1/4000 live births and as high as 60% in low birth weight infants, cerebral hypoxia-ischemia during the perinatal period is the single most important cause of acute mortality and chronic disability in newborns. Herein, we tested the hypothesis that following a hypoxic-ischemic insult hyperbaric oxygen (HBO) treatment can restore high energy metabolite levels in the affected regions of the brain and through this increase in energy levels ameliorate the spread of cell death following the insult. We also investigated if an additional mechanism by which HBO affords its neuroprotection is by altering the expression of the …

The Role Of Brn-3.2 In Retinal Ganglion Cell Differentiation, Jerin Marie Wright

Loma Linda University Electronic Theses, Dissertations & Projects

Within the retina, the POU domain of transcription factors brn-3.0, brn-3.1, and brn-3.2 are present only in retinal ganglion cells. These genes are believed to be involved in establishing neural cell lineages in mammals. In this study brn-3.2 was examined by comparing the number of ganglion cells present during postnatal development in normal mice (+/+), in mice homozygous (-/-) for the brn-3.2 gene, and in adult mice with a heterozygous gene deletion (+/-) for brn-3.2. Optic nerve cross sections were imaged by electron microscopy, and axon profiles counted systematically by hand. These counts were then related to the nerve cross …

Ornithine Decarboxylase And Polyamines In Perinatal Hypoxia, Satyaseelan Packianathan

Loma Linda University Electronic Theses, Dissertations & Projects

Hypoxic and hypoxic/ischemic episodes contribute to various neurological aberrations, learning disabilities, et cetera in surviving infants. Despite major advances in understanding the pathophysiology of hypoxia, the cellular basis for hypoxic-mediated injury remains poorly understood. In addition, the role of developmentally essential enzymes vis á vis their contributions, or lack thereof, to hypoxic-mediated injury has not been adequately investigated. In the series of studies comprising this dissertation, we tested the hypothesis that acute and/or chronic hypoxia affect the activity of omithine decarboxylase (ODC; E.C. 4.1.1.17), the developmentally essential enzyme in polyamine biosynthesis, in the fetal and newborn rat brain. Fetal and …

Periodontal Repair In Dogs : Evaluation Of Rhbmp-2 Carriers, Lauralee Nygaard

Loma Linda University Electronic Theses, Dissertations & Projects

This study evaluated candidate carriers for recombinant human bone morphogenic protein-2 (rhBMP-2) in periodontal reconstructive surgery.

Canine demineralized bone matrix (DBM), bovine inorganic crystallene bone matrix (Bio-Oss), bovine derived microfibrillar collagen matrix (Helistat), poly (D,L-lactide-coglycolide) micropaiticles (PLGA), and polylactic acid granules (Drilac) were used with rhBMP-2 (20 (µg/100 µl implant volume) in routine critical size canine supraalveolar periodontal defects. Contralateral defects in six beagle dogs were randomly assigned to receive: DBM/rhBMP-2, DBM-control, Bio-Oss/rhBMP-2, Helistat/rhBMP-2, PLGA/rhBMP-2, or Drilac/rhBMP-2, all with autologous blood except for Helistat and PLGA. Animals were sacrificed eight weeks post-surgery and block sections of the defects were processed …

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 …

Transforming Growth Factor-Beta 1 Expression In Developing Ovine Teeth As Visualized By In Situ Hybridization, Søren Jepsen

Loma Linda University Electronic Theses, Dissertations & Projects

Recently we demonstrated that human dentin contained relatively high amounts of transforming growth factor beta (TGF-ß) and proposed that dentin TGF-ß originated from odontoblasts. Because of the suggested role of TGF-ß in mediating cellular interactions in dental cell development by paracrine mechanisms, we studied the expression of TGF-ß message in developing teeth by in situ hybridization. 5 µm serial sections of neonatal sheep mandibular third molars that had been fixed in glutaraldehyde and paraffin-embedded were used for in situ analysis. An [³⁵S]-labeled cRNA probe, complementary to TGF-ß1 mRNA, was constructed from human TGF-ß1 cDNA. Northern analysis of total …

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 …

Enhancement Of Intratumor Antibody Distribution With A Bifunctional Antibody Delivery System And With Hyperthermia, Karen Lynn King

Loma Linda University Electronic Theses, Dissertations & Projects

The intratumor distribution of a new monoclonal antibody-hapten-based delivery system was examined. From two marine antibodies, Hybritech, Inc. has developed a bifunctional antibody (BPA) with specificities against CEA (ZCE-025 or GEM 231) and against one of two derivatives of [¹¹¹In]-benzyl-EDTA (CHA 255), EOTUBE or BLEDTA IV, to form ZCE/CHA or CEM/CHA. BFA accumulates in CEA-expressing tissue and clears from non-antigenic tissues prior to administration of an [¹¹¹In]-hapten.

Using five groups of nude mice bearing human colon tumor xenografts (T380), we evaluated different carriers of [¹¹¹In]-EOTUBE to prelocalized ZCE/CHA. We administered all antibodies and haptens …

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 …

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 …