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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
151

Phylogeny of <em>Panthera</em>, Including <em>P. atrox</em>, Based on Cranialmandibular Characters

King, Leigha M 05 May 2012 (has links) (PDF)
Over the past 20 years both morphological and molecular phylogenies have been proposed for extant and extinct members of the family Felidae. However, there remain several discrepancies, particularly within the genus Panthera and the position of Panthera atrox. Consequently, morphologic characters from the skull and dentary were analyzed within Panthera (including all extant and one extinct taxa) to gain a better understanding of pantherine phylogeny. Multiple specimens of each taxon were analyzed, including: P. leo, P. tigris, P. onca, P. pardus , Uncia uncia, and Neofelis nebulosa. Four outgroups were used; Crocuta crocuta, Metailurus ssp., Proailurus lemanensis, and Pseudaelurus validus. From each phylogeny created, despite the outgroup, apparent grouping between Panthera leo, P. tigris, and P. atrox was present. Therefore, P. atrox is likely more closely related to the African lion and the tiger than the jaguar, in contrast to what has been recently suggested.
152

Cranial Morphology and Systematics of Late Pliocene <em>Alligator</em> from Florida, with Notes on <em>Alligator</em> Evolution and Distribution.

Stout, Jeremy Brett 19 December 2009 (has links) (PDF)
Alligator mississippiensis is only distantly related to the other extant alligator (A. sinensis), with much closer relatives known from the geologic past of North America. While A. mississippiensis is well known from the early Pleistocene and later, no Alligator was known from the middle and late Pliocene until the discovery of Haile 7C and 7G late Pliocene (~2 Ma) sites from Florida. These specimens were analyzed using a diagnostic character matrix along with systematic analyses of the results. This research upholds A. mefferdi as a valid taxon, and the utility of the species in fossil identification is further established. The Haile material cannot be placed within either of the aforementioned taxa, and a new species description is planned in a later publication. Furthermore, the systematic analysis used in this research suggests that the line leading to A. sinensis diverged before the earliest known Alligator. An Eocene dispersal of the genus into Asia is plausible.
153

GENETIC MARKERS IN DOGS INFLUENCING CRANIAL CRUCIATE LIGAMENT RUPTURE, ASSOCIATED WITH HYPOMYELINATING POLYNEUROPATHY, AND INDICATING WELFARE

Shawna R Cook (12871985) 27 April 2023 (has links)
<p> Comprehensive mastery of modern genetics involves a myriad of data processing and analytic techniques; these approaches vary because some genetic conditions are the result of single gene mutations that alter protein function, while other more complex diseases and traits are influenced by many genes. This dissertation will undertake investigation of the heritability and genetic risk of cranial cruciate ligament rupture in Labrador Retrievers, a congenital hypomyelinating polyneuropathy in four Golden Retrievers, and the potential usage of telomere length as a biomarker of welfare in dogs housed in commercial breeding facilities. </p> <p>In the first disease studied, 333 Labrador Retrievers with known torn or healthy cranial cruciate ligament(s) were genotyped via SNP array. Heritability of this polygenic trait was calculated using a variety of programs and including different fixed effects. Overall, heritability was high, ranging from 0.550 to 0.893, with sex and sterilization at a young age (≤12 months) strongly influencing risk of cranial cruciate ligament rupture. Neither genome-wide association analyses using this novel dataset of 333 Labrador Retrievers, nor additional analyses combining this data with publicly-available data, identified any significantly associated SNPs. However, the most associated SNPs were located near biologically relevant genes, such as <em>COL1A2</em> (a collagen gene) and <em>ITGA11</em> (a protein that binds to collagen), as well as genes encoding sex hormone receptors, such as <em>FSHR </em>and <em>LHCCGR</em>. Splitting the data in an attempt to predict phenotypes based on genotype was unsuccessful. Future work focused on parsing out genetic influencers of cranial cruciate ligament rupture risk should continue to collect sex, sterilization status, and age at sterilization data, and larger collaborations and use of publicly-available data will be required to increase the data robustness.</p> <p>For the second study, DNA from four unrelated Golden Retrievers diagnosed with congenital hypomyelinating polyneuropathy via neurological examination, electrodiagnostic evaluation, and peripheral nerve pathology were explored for genetic causes. Whole-genome sequencing was performed on all four dogs to identify potential causative variants. When compared to WGS from >1,000 other dogs who were presumably unaffected by this rare disease, likely causative variants were identified in all four dogs. Two cases shared a homozygous <em>MTMR2 </em>splice donor site variant, with a stop codon introduced within six codons following the inclusion of the intron. One case had a heterozygous <em>MPZ</em> missense mutation leading to an isoleucine to threonine substitution. The last case had a homozygous <em>SH3TC2</em> nonsense variant predicted to truncate approximately one-half of the protein. Haplotype analyses using 524 Golden Retrievers indicated that these variants emerged recently. Each of these variants occurred in genes that are associated with the human Charcot-Marie-Tooth group of heterogeneous peripheral nervous system diseases. Testing a population of unrelated Golden Retrievers (n > 200) did not identify any other dogs with these variants, though breeders should be cautious to avoid propagating these alleles.</p> <p>Finally, the last study within this dissertation investigates the relationship between telomere length and metrics such as age, breed, environment, average breed lifespan, parity, and response to a mild social stressor in a population of dogs housed at commercial breeding facilities. FIDO scores (behavioral phenotypes) were collected for all dogs as a measurement of response to a social stressor. This study is not yet complete; many more dogs remain to be recruited in the near future. Telomere lengths were measured using qPCR and compared to a single-copy gene, <em>36B4</em>, for 309 dogs representing 37 breeds or breed crosses. Age was not significantly associated with telomere length after making appropriate corrections (p-value = 0.077). Breed and facility were significantly associated with telomere length after corrections (p-value = 0.010 and <2.2E-16, respectively). Neither parity nor average breed lifespan were associated with telomere length, however, response to a mild social stressor was, with dogs who responded positively having significantly longer telomeres than dogs who responded negatively across all analyses. This preliminary data indicates that, within this population, breed, environment, and response to stress have strong influences on telomere length, while parity and average breed lifespan did not. As this work continues, increased sample sizes will lead to increased power for detecting associations. Future work should examine these identified relationships in other populations of dogs.</p> <p>Taken together, these studies encompass phenotypes of various complexity, and each study encompassed different methodologies utilized in modern canine genetics. The overall goal for this work was to improve canine health, with the potential for translational implications to human health. The identification of genetic markers associated with or causative of disease, or indicative of health and welfare traits, is necessary for reducing the prevalence of disease and increasing the knowledge of welfare metrics in canines, respectively.</p>
154

MRI diagnosis of spontaneous intraventricular tension-pneumocephalus in a 10-month-oldmale Saarloos Wolfdog

Kohl, Stefan, Köhler, Claudia, Kiefer, Ingmar 28 August 2023 (has links)
A 10-month-old male SaarloosWolfdog was presented with a history of multiple neurologic deficits that had acutely progressed. Neurologic examination findings localized signs to the cerebrum and brainstem.Magnetic resonance imaging revealed markedly enlarged and gas-filled lateral ventricles with amass effect leading to cerebellar herniation. A right-sided defect of the cribriform plate with a dysplastic ethmoturbinate was identified as the inlet of air and origin of the intraventricular tension pneumocephalus. Surgical findings were consistent with a ruptured, congenital, nasal meningocele.
155

Beyond cell Adhesion: Exploring the Role of Cadherin-11 Extracellular Processing by ADAM Metalloproteases in Cranial Neural Crest Migration

McCusker, Catherine D. 01 February 2010 (has links)
The migration of the cranial neural crest is an essential part of cranio-facial development in every vertebrate embryo. The cranial neural crest (CNC) is a transient population of cells that forms the lateral border of the anterior neural plate. In the tailbud stage Xenopus embryo, the neural crest cells delaminate from the neural tube, and undergo a large-scale migration from the dorsal to ventral region of the embryo. The CNC travels along distinct pathways, and populates specific regions of the embryos face. Once the CNC ceases migrating, it differentiates into a variety of tissues that are essential for cranio-facial structure and function. Some of these tissues include bones, muscle, cartilage, and ganglia. The CNC receives a concert of signals from neighboring tissues during and after CNC migration as well as signals transmitted among CNC cells, which act together to determine the fate of each CNC cell. Therefore, the proper migration of the CNC is an essential part of cranio-facial development. What molecules are important for the process of CNC migration? As one might imagine, a milieu of different molecules and interactions are essential for this complicated embryological process to occur. The work presented in this dissertation will focus on the role of a cell adhesion molecule that is important for Xenopus CNC migration. Typically, the amount of cell adhesion decreases within tissues undergoing migration. This behavior is essential to allow fluidity within the tissue as it moves. However, cell adhesions are fundamental for cell migration to occur because the moving cells need a platform on which to mechanically propel themselves. These interactions can occur between the migrating cell and extracellular matrix molecules (ECM), or can happen between cells. The cranial neural crest utilizes both cell-ECM and cell-cell interactions during the process of migration. The amount of cell adhesion mediated by either of these mechanisms will depend on where the cell is located within the CNC. Cells located at the periphery of the CNC tissue, which is surrounded by a matrix of ECM, will have more cell-ECM interactions. Cells located deeper in the CNC tissue, where there is little ECM, will rely more on cell-cell interactions. The work presented in this thesis focuses on a cell-cell adhesion molecule that is part of the cadherin superfamily of molecules. With this in mind, these studies should be descriptive of the environment within the CNC, and to a less degree the environment between the CNC and the surrounding tissues. The work presented in this dissertation will focus on cadherin-11, which is a classical cadherin that is specifically expressed in the cranial neural crest during its migration. How does cadherin-11 function in the CNC during this process? The work presented here suggests that the main role of cadherin-11 in the CNC is to perform as a cell adhesion molecule. However, too much cell adhesion is inhibitory to migration. In this respect, many of the studies described in this work indicate that cadherin-11 mediated cell adhesion is tightly regulated during CNC migration. Here I show that cadherin-11 is extracellularly processed by ADAM metalloproteases, ADAM9 and ADAM13, which removes the adhesive domain of cadherin-11. This extracellular cleavage event occurs throughout CNC migration, and is likely the main mechanism that regulates cadherin-11 mediated cell adhesion. Cleavage of cadherin-11 by ADAMs does not seem to affect its ability to interact with cytoplasmic binding partners, â-catenin and p120-catenin. This observation supports the idea that the “purpose” of cadherin-11 cleavage is to regulate cell adhesion, and not to induce (cell autonomous) signaling events. Additionally, the secreted extracellular domain of cadherin-11 (EC1-3) retains biological activity. This fragment can bind to a number of cell surface molecules in tissue culture including full-length cadherin-11 and specific members of the ADAM family. This observation suggests that EC1-3 may interact with full-length cadherin-11 molecules in vivo, and inhibit cadherin-11 mediated cell adhesion during CNC migration. EC1-3 can rescue CNC migration in embryos that overexpress cadherin-11, further supporting this hypothesis. Many of the above observations have been published in my first-author paper entitled “Extracellular processing of cadherin-11 by ADAM metalloproteases is essential for Xenopus cranial neural crest migration” published in the journal Molecular Biology of the Cell in 2009. Some of the unpublished work in this dissertation further focuses on how EC1-3 effects CNC migration in an ex vivo environment. During these studies, the observation was made that overexpression of EC1-3 in a cranial neural crest explant produces abnormal directional movement. In these experiments, it appeared as though certain regions of the CNC explant were “attracting” other regions of the explant. The preliminary studies described in chapter IV are aimed at answering the question; does EC1-3 attract migrating CNC cells? Here, we generated a Matlab program in order to effectively quantify the amount of directional movement of CNC explants presented with a source of EC1-3. In addition to quantifying cell directionality, this program can also decipher between cells moving with random or directed motion, and measure the velocity of cell migration within certain coordinates. Therefore, this program should be useful other ex vivo studies that require the observation of these features. To conclude, the work presented in this dissertation suggests that the role of cadherin-11 during cranial neural crest migration is predominately based on the adhesive function. In order for CNC migration to proceed, the amount of cadherin-11 mediated cell-cell adhesion is tightly regulated throughout this process. These cell-cell interactions are likely important for “sheet” and “branch” migration where CNC cells maintain a lot of cell-cell cohesion.
156

Fracture variations in survivable versus fatal craniofacial blunt force trauma associated with intimate partner violence

Saenz, Nicole 03 November 2023 (has links)
Intimate partner violence (IPV) is a global human rights issue that affects approximately 25% of women and 10% of men and is the leading cause of homicides of women worldwide. Multiple studies have been conducted by medical and dental practitioners to screen for indicators of IPV so that victims can be directed toward resources for help. However, despite its prevalence, injury patterns indicative of intimate partner homicide (IPH) have not previously been studied. Given that blunt force injuries are the primary type of trauma associated with IPV and the second leading trauma associated with IPH (after gunshot trauma), craniofacial fracture patterns from blunt force trauma associated with IPH served as the focus of this study. Using computed tomography (CT) scans obtained from the New Mexico Office of the Medical Investigator of identified victims of IPH, the fracture location and quantity of fractures were compared a compilation of results from previously published studies on IPV. In addition, data on fracture type were collected on the IPH sample, as this can provide information about the fracture-causing blow. This study aimed to determine whether there are differences in fracture patterns associated with IPH versus incidence of IPV that were survived. It was found that some trends present in IPV cases were maintained in IPH cases--such as a concentration of fractures to the mid-face-- fractures in IPH cases were more distributed over the skull and presented with an more frequently on the upper face and cranial vault, as well as fractures to the right side of the body.
157

Management of Cavernous Carotid Artery Aneurysms: A Retrospective Single-Center Experience

Fehrenbach, Michael Karl, Dietel, Eric, Wende, Tim, Kasper, Johannes, Sander, Caroline, Wilhelmy, Florian, Quaeschling, Ulf, Meixensberger, Jürgen, Nestler, Ulf 02 June 2023 (has links)
Objective: While cavernous carotid aneurysms can cause neurological symptoms, their often-uneventful natural course and the increasing options of intravascular aneurysm closure call for educated decision-making. However, evidence-based guidelines are missing. Here, we report 64 patients with cavernous carotid aneurysms, their respective therapeutic strategies, and follow-up. Methods: We included all patients with cavernous carotid aneurysms who presented to our clinic between 2014 and 2020 and recorded comorbidities (elevated blood pressure, diabetes mellitus, and nicotine consumption), PHASES score, aneurysm site, size and shape, therapeutic strategy, neurological deficits, and clinical follow-up. Results: The mean age of the 64 patients (86% female) was 53 years, the mean follow-up time was 3.8 years. A total of 22 patients suffered from cranial nerve deficit. Of these patients, 50% showed a relief of symptoms regardless of the therapy regime. We found no significant correlations between aneurysm size or PHASES score and the occurrence of neurological symptoms. Conclusion: If aneurysm specific symptoms persist over a longer period of time, relief is difficult to achieve despite aneurysm treatment. Patients should be advised by experts in neurovascular centers, weighing the possibility of an uneventful course against the risks of treatment. In this regard, more detailed prospective data is needed to improve individual patient counseling.
158

Canonical Wnt Signaling and Development of Craniofacial Dermis

Tran, Thu T.H 06 April 2011 (has links)
No description available.
159

PCNS: A novel protocadherin involved during convergent extension movements,cranial neural crest migration and somite morphogenesis in Xenopus

Rangarajan, Janaki 02 August 2007 (has links)
No description available.
160

Retrospective Evaluation of Diffusion Weighted MRI Imaging of Head and Neck Cancers and the Correlation with Histopathology

Briody, Ashleigh January 2017 (has links)
No description available.

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