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1
Hatada, Yohko. "Axis formation in the chick embryo". Thesis, University of Oxford, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.260737.
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Darby, N. "Chick embryo hepatic microsomal P-450 system". Thesis, University of Kent, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.353994.
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Al-Thani, Rawda. "Primordial germ cells of the chick embryo". Thesis, University of Reading, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.315524.
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Warrilow, Joanne Maria. "Branchiomotor neuron development in the chick embryo". Thesis, King's College London (University of London), 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.264339.
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Golde, Jolanda Maria Clara Guiliaume van. "Chick embryo as a model in fetal physiology". [Maastricht : Maastricht : Universiteit Maastricht] ; University Library, Maastricht University [Host], 1999. http://arno.unimaas.nl/show.cgi?fid=8570.
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Menna, Tara Marisa. "The regulation of breathing in the chick embryo /". Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=33811.
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From the onset of internal pipping (i.e. embryonal breathing of air cell gas) until hatching, the chorioallantoic membrane (CAM) and the lungs work simultaneously to serve the metabolic needs of the embryo. (1) The carbon dioxide and oxygen exchange rates (V̊O2 and V̊CO2) through the lungs and the CAM were separately, but simultaneously, measured during the last two days of incubation (day 20--21), while ventilation (V̊E) was calculated from the measurements of pressure oscillations in the air cell. When the embryo's total metabolic rate was increased, V̊E was linearly proportional to lung V̊O2 and V̊CO2 and not to the embryo's total metabolic rate. (2) Tracheal pressure and changes in lung volume were quantified through mechanical ventilation of the embryo. The curled up posture of the embryo, the eggshell and its membranes did not represent a significant mechanical constraint to V̊E. (3) V̊E, lung V̊O2 and V̊CO 2 were measured while the CAM compartment was exposed to either 10% O2, 100% O2 or 5% CO2. Total V̊O2 was also measured under these conditions. There is a clear V̊E-sensitivity to CO2 and a rather weak V̊E-sensitivity to changes in arterial oxygenation present at this stage of development.
7
Lim, Tit Meng. "Segmentation in the nervous system of the chick embryo". Thesis, University of Cambridge, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329053.
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Selleck, Mark Anthony James. "Hensen's node and cell commitment in the chick embryo". Thesis, University of Oxford, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.293410.
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Akbareian, Sophie Essmat. "The development of the cranial foramina in the chick embryo". Thesis, Royal Veterinary College (University of London), 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.522151.
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Xu, Hong. "Development of the maxillomandibular trigeminal placode in the chick embryo". Thesis, University of Cambridge, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.612197.
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Russell, Elspeth. "Ions and ion transport mechanisms in the developing chick embryo". Thesis, University of Newcastle Upon Tyne, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287301.
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Patten, Iain. "Mechanisms of floor plate formation in the developing chick embryo". Thesis, University of Sheffield, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.251319.
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Vermeren, Matthieu M. "Molecular basis of peripheral nerve segmentation in the chick embryo". Thesis, University of Cambridge, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.621857.
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Manning, Elizabeth. "Development of the hypothalamic infundibulum in the early chick embryo". Thesis, University of Sheffield, 2004. http://etheses.whiterose.ac.uk/15096/.
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In the posterior neural tube of vertebrate embryos, the secreted signalling molecules Sonic hedgehog (Shh) and bone morphogenetic proteins (BMPs) are expressed at opposite poles of the neural tube, and act antagonistically to pattern the dorso-ventral axis of the neural tube. In contrast, in the ventral diencephalon, in regions that will give rise to the hypothalamus, BMPs and Shh are initially co-expressed. Subsequently, Shh shows a dynamic pattern of expression, first undergoing a medio-Iateral expansion and then disappearing from ventro-medial cells that will form the infundibulum. In this study, I address how Shh is regulated within the hypothalamic infundibulum. Using a combination of fate mapping and gene expression analysis, I demonstrate that cells that initially co-express Shh and BMP7 give rise to the Shh-negative infundibulum. Furthermore, I demonstrate, both in vitro and in vivo, that BMP7 is necessary and sufficient to cause the downregulation of Shh in the infundibulum. Recent studies on the mouse Shh promoter (Jeong and Epstein, 2003) have revealed that aT-box binding site is necessary for the down-regulation of Shh in the infundibulum. Through analysis of Tbx genes, I have found that Tbx2 is expressed in the prospective infundibulum. Furthermore, my studies reveal that its expression is dependent on BMP activity Finally, my studies show that, in addition to their role in regulating Shh expression, BMPs and Tbx2 may also playa role in regulating the size of the infundibulum. Analysis with the M-phase marker, PH3, reveals that, following exposure to BMPs, prospective infundibular cells are transiently cell cycle arrested, entering a synchronised cell cycle once BMP activity is lost, and Tbx2 is expressed. Together, my results suggest that BMPs act through Tbx2 in order to control the domain of Shh expression within the forming hypothalamus, whilst simultaneously controlling the size of this progenitor domain.
15
Winnick, Blake Edward. "The Effects of Glyphosate Based Herbicides on Chick Embryo Development". Thesis, University of North Texas, 2013. https://digital.library.unt.edu/ark:/67531/metadc500146/.
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Glyphosate based herbicides are among the most widely used herbicides in the world. The purpose of this study was to determine developmental toxicity of glyphosate, the active ingredient in the common herbicide Roundup, on developing chicken embryos. Few studies have examined toxic effects of glyphosate alone versus the full compound formulations of Roundup, which include adjuvants and surfactants. Adjutants and surfactants are added to aid in solubility and absorption of glyphosate. In this study chicken embryos were exposed at the air cell on embryonic day 6 to 19.8 or 9.9 mg / Kg egg mass of glyphosate in Roundup or glyphosate only. Chickens treated with 19.8 and 9.9 mg / Kg glyphosate in Roundup showed significant reduction in survivability compared to glyphosate alone treatments and controls. On embryonic day 18, embryos were sacrificed for evaluation of developmental toxicity using wet embryo mass, dry embryo mass, and yolk mass as indicators. Morphology measurements were taken on liver mass, heart mass, tibiotarsus length and beak length. Embryos treated with 19.8 mg / Kg glyphosate and 9.9 mg / Kg glyphosate in Roundup showed significant reductions in wet and dry embryo mass and yolk mass. Tibiotarsus length in 9.9 mg / Kg glyphosate in Roundup treatments were significantly reduced compared to 9.9 mg / Kg glyphosate treatments. Beak length was significantly reduced in 9.9 mg /Kg glyphosate in Roundup treatments compared to all other groups.
16
Canning, David Richard. "The mechanisms of formation of the embryonic axis". Thesis, University of Oxford, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329968.
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Parson, Simon H. "Control of growth and development of neurones in the chick embryo". Thesis, University of Edinburgh, 1991. http://hdl.handle.net/1842/26836.
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This thesis is in two major sections: (1) Segmental sensory innervation: During the segmental, sensory innervation of the periphery, neurones situated in the dorsal root ganglia grow out axons at different rates. These vary with segmental level of the ganglia. The most rapid rates of axonal advancement are seen from those ganglia which innervate limb as opposed to non-limb ganglia. How are these differential axonal growth rates controlled? This problem has been addressed using cell culture techniques. No evidence for a segmentally regulated, intrinsic growth mechanism has been found. Further some common constituents of the peripheral fiels of these neurones were also, on the whole, ineffective in regulating neurite growth rates in culture. I conclude from this that some, as yet, unidentified factor in the periphery is reponsible for the enhanced growth rate of axons into limb tissue. A number of differences in the neurite growth patterns of neurones isolated from embryos at different stages of development were noted. This suggests that neurite growth is regulated developmentally if not segmentally. Neurite lengths from cultured neurones were found to benon-normally distributed. They showed a positively skewed, multimodal form. This was not explained by differences in neurite length, branch pattern or the stage of development of the neurones. In the light of this, a quantal hypothesis of neurite growth is proposed, and modelled using Poisson statistics as a theoretical basis. (2) Neuronal toxicity of cytosine-B-D-Arabinofuranoside: Cytosine-B-D-Arabinofuranoside (AraC) is a commonly used anti-mitotic agent in neural cultures. In this study it is also shown to be toxic to cultured neurones and to inhibit neurite growth. This toxicity is dose dependent and inhibited in the presence of 2'DeoxyCytidine (a metabolic precursor of AraC). A relationship between high metabolic demand (neurite growth) and AraC toxicity is discussed in the light of other experimental work.
18
Hicks, Julie Ann. "MicroRNAs in the spleen and liver of the developing chick embryo". NCSU, 2007. http://www.lib.ncsu.edu/theses/available/etd-03252007-215944/.
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MicroRNAs are small (~19-24nt) non-coding RNAs that are involved in the regulation of gene expression. They are mainly expressed in development and many are expressed in a temporal as well as, a spatial manner. It is thought they may regulate up to 30% of all genes. Pyrosequencing using 454 Life Science technology is becoming the preferred method for microRNA profiling ad sequencing compared to the previous method of cloning and using traditional sequencing techniques. Use of 454 Life Sciences technology allows for a greater coverage of microRNAs and increases the chances of sequence low abundance microRNAs. In the current project we created four small RNA libraries from embryonic chick tissues, the spleen and liver at developmental time points E15 and E20. These libraries were then sequenced using 454 Life Sciences pyrosequencing. A total of 92,919 sequence reads were obtained, representing a total of 52,001 known chicken microRNAs. Of these 92,919 reads, 52,001 represented miRNAs matching the miRBase G. gallus database, and 3,472 were not found in the G. gallus database but were homologues of miRBase miRNAs from other species. Of these homologous reads 391 represented potential novel miRNAs. Other small RNAs, such as tRNA and rRNA, represented 24,672 of the reads, and 12,383 reads represented other types of sequences, such as degraded mRNA. More than one hundred different known miRNAs were identified in this study, and many were expressed in all four libraries. Common miRNAs that yielded multiple reads from all four libraries included miR-125b and miR-21, which are involved in general processes of cellular proliferation. Overall, the spleen libraries had a larger array of miRNAs than the liver libraries. Much of spleen development occurs during the later stages of embryonic development, so we can reasonably expect that many gene expression changes occur during these stages. As a result of this study, we identified nine potential novel chicken miRNAs. These novel miRNAs appear to be tissue-specific. The potential novel miRNAs appeared to be expressed at lower levels than some of the known miRNAs, which could indicate that most of the highly-expressed chicken miRNAs have already been identified, whereas, for the most part, the miRNAs expressed at low levels remain to be discovered.
19
Rashidi, Hassan. "Developing the chick embryo model to study mesenchymal stem cell differentiation". Thesis, University of Nottingham, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.659205.
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Human mesenchymal stem cells have attracted significant attention during the last decade as a versatile tool for cell therapy, gene therapy and tissue engineering. The existence of mesenchymal stem cells in adult tissues and their capacity for differentiation into multiple lineages are major benefits for clinical applications, circumventing the ethical and safety concerns surrounding the use of embryonic stem cells. It has been long established that mesenchymal stem cells have the potential to differentiate into mesenchymal lineages such as bone, cartilage and adipose tissue. Recent studies have uncovered the potential of mesenchymal stem cells to differentiate into endodermal and ectodermal derivatives, suggesting a greater plasticity than originally envisaged. In the current study, a novel approach using the chick embryo was developed to investigate the differentiation potential of bone marrow-derived human mesenchymal stem cells when exposed to developmental signals in vivo. In order to investigate the suitability of the chick embryo as a host, mesenchymal stem cells were first transplanted into fore- and hind limb of stage 17 chick embryos. Expression of differentiation markers were subsequently analysed using immunocytochemistry and molecular analysis. Expression of osteogenic-specific genes such as alkaline phosphatase, RUNX2 and osteocalcin was observed in human mesenchymal stem cells grafted into wing and limb buds of the chick embryo. To investigate the extra-mesodermal differentiation potential of mesenchymal stem cells, expression of lineage-specific genes was subsequently analysed after grafting mesenchymal stem cells into the chick neural crest. Mesenchymal stem cells showed extensive migration through head mesenchyme after injection into the chick neural crest. Injected cells also significantly up-regulated neural crest specific markers such as SLUG, FOXD3 and MITF, suggesting differentiation toward neural crest cell lineages.
20
Balaskas, Christos. "Cellular development of the enteric nervous system in the chick embryo". Thesis, University College London (University of London), 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.267801.
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Broom, Emma Ruth. "Studies of the hindbrain roof plate organiser in the chick embryo". Thesis, King's College London (University of London), 2012. https://kclpure.kcl.ac.uk/portal/en/theses/studies-of-the-hindbrain-roof-plate-organiser-in-the-chick-embryo(488d39db-40d7-4b63-8b0c-3129f3da3658).html.
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Organisers are specialised groups of cells that non-autonomously pattern adjacent cell populations. The dorsal midline, or roof plate, of the developing CNS is one such organiser and is required for the specification of specific subtypes of dorsal neurons. Organisers often comprise boundaries between molecularly distinguishable compartments, however the roof plate does not fit with this model; for the most part it constitutes a narrow strip of cells that separate two molecularly indistinguishable compartments (the two halves of the neural tube), but at certain anteroposterior locations, such as the hindbrain, it is expanded to form a thin epithelium that tents over a ventricle. Using chick embryos, I have investigated a hypothesis that reconciles the roof plate with this emergent model, in which the organiser properties of the roof plate are invested in its boundaries. Using in vitro co-culture, I show that the gdf7- positive roof plate boundary and its signalling properties can be regenerated in roof platederived tissue at the interface between hindbrain roof plate epithelium and neuroepithelium. Further, this gdf7-positive boundary is required for the expression of cath1, which marks the dorsal-most pool of neural progenitors in the hindbrain. Many organisers require Notch signalling and downstream Hairy/ Enhancer of split (Hes) transcription factors for their formation or maintenance. Using electroporation of the hindbrain roof plate epithelium – neuroepithelium boundary, I find that Delta-Notch signalling is sufficient to convert cells from a roof plate epithelial to a roof plate boundary fate. Further, correct levels of expression of chairy2 (a hes1 homologue) are required for the maintenance of the roof plate boundary. Finally, I show that the roof plate boundary is a bidirectional signalling centre that not only patterns adjacent neuroepithelium, but is also required for the differentiation of choroid plexus epithelium from roof plate epithelium.
22
Keats, Holly Denise. "Gene regulation in the ventral midbrain of the developing chick embryo". Thesis, University of Portsmouth, 2016. https://researchportal.port.ac.uk/portal/en/theses/gene-regulation-in-the-ventral-midbrain-of-the-developing-chick-embryo(63b8c7f5-11fe-431c-8317-7e6d57d425a7).html.
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Within the ventral midbrain of the developing vertebrate embryo there is a transient area of conserved gene patterning called the midbrain arcs, this patterning influences the formation and position of nearby nuclei, as well as the position of the MLF (medial longitudinal fascicle) axon tract in the early axon scaffold. A hypothetical regulatory loop has been identified between the genes Nkx1.2 and Emx2 during midbrain arc patterning and this project aimed to identify if a highly conserved non-coding sequence named Nkx1.2.1 acted as an enhancer for the Nkx1.2 gene, and bound directly with the Emx2 protein. Electroporation of a reporter construct containing the Nkx1.2.1 sequence in the chick embryo identified the element was active specifically in the ventral midbrain during the time of midbrain arc patterning. The Nkx1.2.1 sequence was then analysed for binding affinity with the Emx2 protein using EMSA. The full Emx2 sequence could not be produced in a soluble form, but two artificial sub-forms of the protein were produced. The closest binding affinity identified was a value of 0.2 KdμM, compared to the control experiment using a non-specific sequence of DNA of 2.6 KdμM.
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Osório, da Silva Liliana Alexandra. "Development of the caudal-most neural crest in the chick embryo". Paris 6, 2008. http://www.theses.fr/2008PA066208.
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La crête neurale (CN) issue de la région troncale du tube neural (TN) de l’embryon de poulet donne naissance aux neurones et cellules gliales du système nerveux périphérique et aux mélanocytes de la peau. Cependant, dans la région troncale la plus caudale (c) (niveaux somitiques 47 à 53), les cellules de CN (CCN) ne fournissent pas de neurones in vivo, ni en cultures in vitro (Catala et al. , 2000). Il en résulte l’absence de ganglions rachidiens alors que les motoneurones sont également absents dans cette région (Afonso & Catala, 2005). Afin d’élucider les causes de l’absence de dérivés neuraux de la CNc, nous avons entrepris d’analyser l’expression de plusieurs molécules impliquées dans les différentes étapes de la formation de cette structure. Nous avons trouvé que la plupart des acteurs moléculaires connus de la spécification de la CN sont présents dans la région dorsale du TNc dès que celui-ci est formé à E4, à l’exception de Msx1 qui n’est jamais exprimé à ce niveau. Néanmoins, seul un faible nombre de CCN migre dorsalement au TNc à E5. Ce défaut de migration semble être en rapport avec un défaut dans l’acquisition du phénotype mésenchymateux par les CCNc prospectives, qui pourrait être dû à une signalisation perturbée de BMP (maintien de Noggin) et de WNT (absence de Wnt1). Simultanément, une apoptose massive est détectée dans la moitié dorsale du TNc. La transplantation rostrale du TNc ou des somites montre que l’absence de dérivés neuraux est une propriété intrinsèque des CCNc et ne semble pas dépendre de l’influence des somites. L’expression ectopique de Noggin dans la région dorsale du TN troncal mime les caractéristiques des CCNc (faible nombre de cellules et absence des dérivés neuronaux). Enfin, nous avons évalué le rôle de Bmp4 et de ses cibles Msx1 et Wnt1 dans la spécification neuronale. L’ensemble de nos résultats montre que le TNc constitue un modèle précieux pour élucider les mécanismes moléculaires qui contrôlent l’émergence et différenciation des CCN.
24
Fyfe, D. M. "An analysis of the development of the scleral ossicle system in the chick embryo". Thesis, University of Aberdeen, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.379211.
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Li, Naixin. "Dorso-ventral Differentiation and Specification of the Mesencephalon in Early Chick Embryos". kostenfrei, 2007. http://www.opus-bayern.de/uni-wuerzburg/volltexte/2009/3295/.
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Waddell, Trinity Q. "Role of Transient Receptor Potential Channels in Epithelial Morphogenesis in Chick Embryo". BYU ScholarsArchive, 2019. https://scholarsarchive.byu.edu/etd/8112.
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Transient Receptor Potential channels (TRP) are a superfamily of cationic specific ionchannels that are regulated by various stimuli such as temperature, pH, mechanical stress, ligandsand ion concentration. The role of TRP channels in disease states such as autosomal dominantpolycystic kidney disease, cancer metastasis, and developmental defects lend credence to thebelief that they play an important part in epithelial morphogenesis events. The development ofsomites, neural tube closure and migration of neural crest cells to form things such as the faceand heart is a good developmental model for the aforementioned cellular processes. We haveshown that TRP channels can be found in the developing ectoderm, hindbrain, and heart and thatthe inhibition of TRP channels in a developing embryo results in phenotypes suggestingperturbation of cellular remodeling processes. This leads to the question of the specific role ofTRP channels in the epithelial mesenchymal transition and remodeling in developing chickembryos.
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Hoggar, Emily. "Identification of novel drivers of collateral vessel remodelling in the chick embryo". Thesis, University of Sheffield, 2014. http://etheses.whiterose.ac.uk/7438/.
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Arterial occlusion accounts for high rates of mortality in the western world. Strategies to bypass an occlusion by activating collateral vessels could reduce the consequences of arterial diseases. This thesis investigates the genes involved in collateral vessel remodelling in the chick embryo to gain insight into the process. Ligation of the right proximal vitelline artery of HH st 17 chick embryos occluded blood flow to the right hand side of the extra-embryonic tissue and vitelline vessel network. Collateral vessels were seen to develop from the pre-existing, left (unligated) vitelline artery and extended across the midline to carry arterial blood to the un-perfused side of the extra-embryonic tissue. The remodelling process was active over 48 hours and developed many small collateral vessels into a few, main conducting arteries. The number of collateral vessels peaked at 12 hours post tied-ligation and then decreased, whilst collateral vessel diameter continued to increase over the time period. Analysis of the global transcriptional profile of collateral vessels in the chick embryo was assessed following ligation, during early stages of collateral vessel development (4 hours), at the point of pruning and remodelling of the collateral network (12 hours). Collateral vessel formation in the chick embryo was found to be associated with a unique and specific gene expression profile. Phosphodiesterase 10A (PDE10A), an cAMP hydrolysing enzyme, was upregulated in tied-ligated embryos at 4 hours post tied-ligation and hypothesised to play a role in the remodelling process. To study PDE10A papaverine hydrochloride was used to inhibit the enzyme. Papaverine had no effect on normal vessel development but significantly impaired collateral vessel diameter from 6 hours post-ligation. This effect was rescued by co-treatment with Protein Kinase A inhibitor, Rp-8-Br-cAMPS. To begin an assessment of the role of PDE10A in collateral vessel remodelling, proliferation was investigated, in vivo. However, a mechanism of action for PDE10A has yet to be elucidated.
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Runswick, Sarah Kay. "Expression of laminin in the developing central nervous system of the chick embryo". Thesis, University of Liverpool, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.295823.
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Itani, Nozomi. "Oxidative stress and early origins of cardiovascular disease : studies in the chick embryo". Thesis, University of Cambridge, 2016. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.709533.
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Pakiraih, Joanna Floria. "Software Tools Design for Analysis of Kinematic and Force Measurements in Chick Embryo". OpenSIUC, 2011. https://opensiuc.lib.siu.edu/theses/690.
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The objective of my thesis was to develop software tools for the analysis of kinematic measurements and force measurements from chick embryos. The ultimate goal behind my objective is to assist in chick embryonic studies to understand the contribution of sensory input to the development of motor circuitry. For this reason, I designed analytical tools in MATLAB software to analyze kinematic recordings and force signal recordings. Then, I applied these tools to recording of embryos whose movements have been obstructed with a force probe to test the hypothesis that embryos utilize sensory information to coordinate movements. For kinematic analyses, embryos were videotaped at embryonic day 9 (E9) and E11 and digitized for obstructed and unobstructed conditions. Results indicated that there was a significant change observed at the ankle joint in E11s in the presence of obstruction. Analysis of spatial utilization in response to the obstruction showed the adaptive behavior of E11 embryos. An additional observation is that the embryo is inclined to use new space in the presence of obstruction. However, E9 embryos did not show significant changes in spatial usage. For force measurements in these experiments, a small strain gage was used as a force probe that measures force by converting it to a voltage signal. In view of the fact that a single sensor only provided information for force produced along a line, it was necessary to use two probes aligned orthogonal to each other. The program calculated the magnitude and direction of the force applied by comparing the ratio of forces measured by the two sensors. Results indicated that the force generation is higher in E11 embryos than in E9 embryos. Overall, results indicate that E11 embryos show a greater possibility to adapt to the complexities of spatial restriction. I expect that the designed software tools hold relevance not only in our specific field of study but also in the general area of kinematic movement analysis, gait analysis, robotics, etc.
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Ghaffari, Mithra. ""Glial Islands" promote survival and regeneration of neurites from chick embryo retinal neurons". CSUSB ScholarWorks, 1997. https://scholarworks.lib.csusb.edu/etd-project/1458.
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McKinnon, Lise Anne. "Developmental regulation of muscarinic acetylcholine receptor expression in embryonic chick heart and retina /". Thesis, Connect to this title online; UW restricted, 1997. http://hdl.handle.net/1773/6263.
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Veitch, Emma. "Development of the pharyngeal arches". Thesis, King's College London (University of London), 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.326243.
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Venter, Chantelle. "An in ovo investigation of the cellular effects of the heavy metals cadmium and chromium alone and in combination". Diss., University of Pretoria, 2014. http://hdl.handle.net/2263/46019.
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Many heavy metals are essential for biological functions; however some of these metals,
especially at high concentrations, can have serious adverse effects on humans. The main
sources of heavy metal exposure are through agriculture, transport, mining and related
operations. South Africa has a thriving mining industry and is known for its rich mineral
resources, but due to the incorrect method of disposal of the waste from these mines,
substances, including heavy metals, get into the water and air supply, affecting the people
living in close proximity to these mines. Exposure is through inhalation of contaminated air
and consumption of contaminated food and water. The most vulnerable to heavy metals are
the developing fetus, because of the high rate of cell division and differentiation.
In the current study, two heavy metals cadmium (Cd) and chromium (Cr) were chosen based
on the possibility of being exposed to them in South Africa. Thus, the aim of this study was
to investigate the possible cellular effects of the heavy metals Cd and Cr alone and in
combination, at different concentrations, on brain, liver and kidney tissue by using a chick
embryo model.
This model was successfully implemented over a 14 day period after which the embryos
were terminated and the brains, livers and kidneys removed and processed for light- and
transmission electron microscopy (with energy dispersive spectroscopy and electron energyloss
spectroscopy). In addition, the effect of Cd and Cr alone and in combination on DNA
structure and micronuclei formation was evaluated. The levels of the major antioxidant
component, glutathione was determined in the brains of the chick embryos. At low concentration of Cd and Cr alone and in combination, a hormesis effect was observed
in the survival rates and weights of the chick embryos, while at x1000 physiological dose
(PD) Cr and Cd alone and in combination the effects were toxic. The majority of viable
embryos did not have any macro-anatomy abnormalities.
Morphological evaluation of the brain, liver and kidney samples revealed that Cd caused
severe alterations at its highest concentration with minor alterations at the lower
concentrations. Cr and the metal combination groups on the other hand, only caused
minimal alterations throughout the concentration ranges evaluated. The presence of Cd and
Cr alone and in combination in the liver tissue was confirmed with the electron energy-loss
spectroscopy analysis that detected these metals in the nuclei, mitochondria and Golgi
complexes of the hepatocytes. This might contribute to the ultrastructural changes observed
in this organ. The genotoxicity testing on the red blood cells revealed no substantial
differences, as only a few micronuclei were present.
Although heavy metals cause DNA damage through an indirect mechanism of oxidative
damage, the presence of Cd and Cr in the nucleus and mitochondria indicates that these
metals may have a direct effect on DNA structure. With DNA agarose gel electrophoresis it
was found that Cd and Cr alone and in combination caused DNA fragmentation. In the brain,
GSH levels were normal; however changes may be the result of Cd and Cr causing the
depletion of other antioxidant elements such as glutathione reductase, glutathione
peroxidase, superoxide dismutase and catalase.
In conclusion, this study indicates that Cd and Cr alone and in combination are toxic to the
chick embryo. Cd is more toxic than Cr, and both metals accumulate in the nuclei and
mitochondria where they induce damage either through oxidative and/or other mechanisms
associated directly with DNA damage.Dissertation (MSc)--University of Pretoria, 2014.
tm2015
Anatomy
MSc
Unrestricted
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Picard, Cyril. "Caractérisation de nouvelles subpopulations de progéniteurs musculaires au cours du développement embryonnaire des amniotes". Thesis, Aix-Marseille, 2013. http://www.theses.fr/2013AIXM4000.
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Chez les vertébrés, les muscles squelettiques du corps sont dérivés de la partie dorsale dessomites, le dermomyotome, structure transitoire mésodermique. Une première étape demyogenèse aboutit à la formation d’un muscle primitif, le myotome primaire, à partir desbordures du dermomyotome : ces cellules constituent les premières fibres musculaires, et formentl’architecture de base du futur muscle. Dans un second temps, une population de progéniteursmusculaires émerge de la région centrale du dermomyotome. Cette population est primordialedans la constitution du muscle. Elle prolifère, et une partie d’entre elle fusionne aux fibresexistantes pour donner les fibres multinucléées adultes. Finalement, une partie des progéniteursmusculaires reste indifférenciée jusqu’à l’âge adulte et compose la population de cellules souchesmusculaires, les cellules satellites. Ainsi, les progéniteurs musculaires contribuent audéveloppement musculaire tout au long du développement embryonnaire et foetal, mais égalementà la myogenèse post-natale avec les cellules satellites.Lors de ma thèse, je me suis intéressé à cette population de progéniteurs musculaires. Deux souspopulationsde progéniteurs musculaires ont précédemment été identifiées dans notre laboratoireau cours de l’embryogénèse précoce de poulet, l’une exprimant le facteur de transcription Pax7,l’autre co-exprimant Pax7 et le facteur de différenciation myogénique précoce Myf5. Face àl’absence de données concernant les progéniteurs musculaires, et à l’importance de cettepopulation pour la myogenèse, j’ai réalisé une étude systématique des progéniteurs musculairestout au long du développement embryonnaire et foetal de deux organismes modèles : le poulet etla souris. J’ai pu montrer que ces deux sous-populations coexistent tout au long dudéveloppement, depuis l’émergence des progéniteurs de la partie centrale du dermomyotome,jusqu’au moment où ces cellules deviennent des cellules satellites à la fin du développementfoetal. De manière très intéressante, j’ai pu montrer qu’au sein des progéniteurs musculaires, lapopulation principale co-exprime Pax7 et Myf5, et prolifère activement, alors que la populationPax7 est mineure et prolifère à un taux moins élevé. Cette dernière entre de manière importanteen quiescence à la fin du développement embryonnaire. Ces caractéristiques sont semblablesentre le poulet et la souris, et montrent que des stratégies cellulaires et moléculaires similairessont conservées au sein des amniotesDuringembryonicandfetallife,skeletalmusclegrowthisdependentupontheproliferationandthedifferentiationofapopulationofresidentmuscleprogenitors,fromwhichderivethemusclestemcellsof theadult,thesatellitecells.Underpoorlydefinedextrinsicandintrinsicinfluences,muscleprogenitorsproliferate,differentiateorenteraquiescentstatetobecomereservesatellitecells.Despitetheir primordialrole,surprisinglylittleisknownonthehomeostasisofresidentprogenitorsduringembryogenesis.Preliminarystudiesinchickandmousedescribingthekeyprogenitorpopulationscontributingtomusclegrowthduringembryogenesishaveledtodifferingresultsthatcouldbeduetotechnicalissuesortofundamentaldifferencesbetweenanimalmodels.Toaddressthisquestion,we haveundertakenacomprehensiveanalysisofthestateofdifferentiationandproliferationofmuscleprogenitorcellsfromthetimeoftheiremergencewithinthedermomyotomeuntillatefetallife,whenthey adoptasatellitecell-likepositionunderthebasallamina.Thiswasdonebyimmunostainingagainstkeyplayersofmyogenicdifferentiation,inmuscleschosenfromdifferentregionsofthebodyintwo modelorganisms,thechickandmouse.This studyidentifiedtwoco-existingpopulationsofprogenitorsduringembryonicandfetallifeinboth chickandmouse:aminor,slow-cyclingpoolofundifferentiatedresidentprogenitorswhichexpress Pax7,co-existingwithamajorfast-cyclingpopulationthatco-expressPax7andtheearlymyogenicdifferentiationmarkerMyf5.Wefoundthattheoverallproliferationrateofbothprogenitorsdrasticallydecreasedwithembryonicage,asanincreasinglylargeportionofslowandfast-cyclingprogenitorsenteredquiescenceduringdevelopment.Together,thisdatasuggeststhatthecellularstrategiesthatdrivemusclegrowthduringembryonicand fetallifeareremarkablyconservedinamniotesthroughoutevolution.Theyrelyonthetightregulationofproliferation,entryinquiescence,andmodulationofthecellcycle’slengthforbothoftheco-existingpopulationsofmuscleprogenitorstomaintainthehomeostasisofgrowingmusclesduringdevelopment
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Stander, Cornelia Steynberg. "An ultrastructural and light microscopic study of melanocyte differentiation in chick embryos". Master's thesis, University of Cape Town, 1991. http://hdl.handle.net/11427/27149.
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The embryonic source and chemical nature of those factor/s directing the in vivo differentiation of melanocytes from crest cells are as yet unknown. To begin to address this issue, it is important to establish exactly when and where these signa/s first exert their effects. Therefore, in the present study, overtly differentiated melanocytes containing melanin were quantitated in developing Black Australorp X New Hampshire Red chick embryos. In contrast to previous studies, it was found that embryos synthesize melanin from as early as Day 5 of development, and that at this stage, the melanocytes are predominantly dermally located. Between 5 and 8 days, the numbers of both dermal and epidermal melanocytes increase, after which the dermal melanocyte population declines rapidly while the number of epidermal melanocytes continues to increase. These findings suggest that premelanocytes do not have to be epidermally located to initiate terminal differentiation and implicate the dermis as a possible source of melanocyte inducing factor/s. The next step was to examine stages of development prior to the onset of pigment production. For this reason, tyrosinase was purified for use as antigen in the production of a polyclonal antibody. The antibody was tested for specificity by western blotting, - immunocytochemistry and immunoinhibition procedures. Lack of specificity was demonstrated, rendering it unsuitable as an antibody marker for early melanocytes. Fowl melanocytes are thought to differentiate into either eumelanosome- or pheomelanosome synthesizing cells. To test the validity of this concept, embryonic skin of the red/black cross breed were screened for possible mixed type melanocytes by electron microscopy. The melanocytes contained melanosomes with a matrix of irregularly arranged filaments amongst typical eumelanogenic melanosomes. This suggests that these chick melanocytes may synthesize both eumelanosomes and pheomelanosomes in single cells. In a further study on pure breeding New Hampshire Reds, it was found that the melanocytes contained a mixture of typical and less typical pheomelanosomes. Outer membrane indentations in the latter melanosome type suggest that tyrosinase may enter these pheomelanosomes by a mechanism related to that proposed for the melanosomes of goldfish.
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Kowalski, William J. "Quantification of vascular morphogenesis in the chick embryo and its relationship to the hemodynamic environment". Research Showcase @ CMU, 2013. http://repository.cmu.edu/dissertations/284.
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Congenital heart disease (CHD) has the highest incidence and mortality rate of all birth defects in the U.S., occurring in at least 8 of every 1000 live births, and accounting for more than 24% of birth defect related infant deaths. Clinical and experimental data indicate that the hemodynamic environment has a significant role in the etiology of CHD, motivating the development of fetal valvuloplasty to reverse the progression of heart defects in utero. The efficacy of this intervention relies heavily on understanding the biomechanical relationships between blood flow and cardiovascular growth and remodeling. This thesis describes several studies using the chick embryo model designed to quantify vascular morphogenesis in vivo and link the observed trends to hemodynamic forces such as wall shear stress (WSS). Morphogenesis of the embryonic aortic arches, a series of bilaterally paired vessels surrounding the foregut and the precursors to the great vessels, was investigated using fluorescent dye injection and optical coherence tomography imaging. These experimental results were combined with computational fluid dynamics models of flow through the aortic arches, which revealed a correlation between transitioning aortic arch patterns and acute increases in WSS. Additionally, a regression analysis found a strong polynomial relationship between luminal aortic arch growth and deviations in WSS. Transformations of the aortic arches were further investigated using a computational optimization-based growth model. The model demonstrated that selection of the adult single aortic arch was influenced by the rotation of the outflow tract of the heart. The principle of minimum work, combined with this model, accurately predicted the transformation to a single aortic arch configuration. In order to support predictive computational models, quantitative data of vascular growth is required. Morphogenesis of an embryonic vitelline artery was tracked using a time-lapse, long-term optical coherence tomography based imaging system. Global and local growth of the artery was quantitatively analyzed at high spatial and temporal resolution. Finally, a model of hypoplastic left heart syndrome in the chick embryo was used to determine alterations in intracardiac flow patterns that may lead to the progression of this defect. Out of three venous injection sites, two shifted their flow pattern significantly. This change was observed soon after the intervention to generate the defect was performed, suggesting that flow disruption is an early insult leading to hypoplastic left heart syndrome. Together, these studies support the importance of the hemodynamic environment in determining vascular morphogenesis in the embryo. The combined experimental and computational approach provided new quantitative data of embryonic vascular morphogenesis. The results of these studies and the methods established in this thesis lay the foundation for future research on the biomechanics of cardiovascular development.
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Sneesby, Kyra, i n/a. "Gene Expression in Embryonic Chick Heart Development". Griffith University. School of Biomolecular and Biomedical Science, 2003. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20030924.153514.
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Establishment of the biochemical and molecular nature of cardiac development is essential for us to understand the relationship between genetic and morphological aspects of heart formation. The molecular mechanisms that underly heart development are still not clearly defined. To address this issue we have used two approaches to identify genes involved in early chick cardiac development. Differential display previously conducted in our laboratory led to the identification of two gene fragments differentially expressed in the heart that are further described in this thesis. The full-length cDNA sequence of both eukaryotic translation initiation factor-2b (eIF-2b) and NADH cytochrome b5 reductase (b5R) were isolated using library screening. The upreglation of these genes during heart development is expected given the heart is the first functional organ to form in vertebrates and protein synthesis and cell metabolism at this stage of development is maximal. Limitations in the differential display approach led to the development and optimisation of a subtractive hybridisation approach for use with small amounts of cells or tissue. To focus on cardiac gene expression during the initial phases of heart development, subtractive hybridization was performed between the cardiogenic lateral plate mesoderm of Hamburger and Hamilton stage 4 embryos and the heart primordia of stage 9 embryos. Of the 87 independent clones identified by this procedure, 59 matched known sequences with high homology, 25 matched unknown expressed sequence tag (EST) sequences with high homology, and 3 did not match any known sequence on the database. Known genes isolated included those involved in transcription, translation, cell signalling, RNA processing, and energy production. Two of these genes, high mobility group phosphoprotein A2 (HMGA2) and C1-20C, an unknown gene, were chosen for further characterisation. The role of each gene in early chick heart development and indeed development in general, was addressed using techniques such as in situ hybridisation, transfection analysis, in ovo electroporation and RNAi. HMGA2 is a nuclear phosphoprotein commonly referred to as an architectural transcription factor due to its ability to modulate DNA conformation. In keeping with this function, HMGA2/GFP fusion protein was shown to localise to the nucleus and in particular, the nucleolus. In situ hybridisation analysis suggested a role for HMGA2 in heart and somite development. HMGA2 expression was first detected at HH stage 5 in the lateral plate mesoderm, a region synonymous with cells specified to the cardiac fate. HMGA2 was also strongly expressed in the presomitic segmental plate mesoderm and as somites developed from the segmental plate mesoderm, the expression of HMGA2 showed an increasingly more restricted domain corresponding to the level of maturation of the somite. Restriction of HMGA2 expression was first detected in the dorsal region of the epithelial somite, then the dorsomedial lip of the dermomyotome, and finally the migrating epaxial myotome cells. The novel intronless gene, C1-20C, predicts a protein of 148 amino acids containing a putative zinc finger binding domain and prenyl binding motif. Zinc binding assays showed that the zinc finger domain of C1-20C/MBP fusion protein bound over six times the quantity of zinc compared to MBP alone, although not in a 1:1 stoichiometric molar ratio. C1-20C/GFP fusion protein was shown to localise to as yet unidentified intracellular cytoplasmic vesicular compartments. These compartments did not colocalise with the endosome/lysosome pathway, aparently ruling out a role for C1-20C in protein trafficking, recycling or degradation. Expression of C1-20C in the chick embryo suggests a possible role in heart and notochord development and preliminary results using siRNA suggest that C1-20C is involved in normal heart looping.
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Sneesby, Kyra. "Gene Expression in Embryonic Chick Heart Development". Thesis, Griffith University, 2003. http://hdl.handle.net/10072/367647.
Pełny tekst źródłaStreszczenie:
Establishment of the biochemical and molecular nature of cardiac development is essential for us to understand the relationship between genetic and morphological aspects of heart formation. The molecular mechanisms that underly heart development are still not clearly defined. To address this issue we have used two approaches to identify genes involved in early chick cardiac development. Differential display previously conducted in our laboratory led to the identification of two gene fragments differentially expressed in the heart that are further described in this thesis. The full-length cDNA sequence of both eukaryotic translation initiation factor-2b (eIF-2b) and NADH cytochrome b5 reductase (b5R) were isolated using library screening. The upreglation of these genes during heart development is expected given the heart is the first functional organ to form in vertebrates and protein synthesis and cell metabolism at this stage of development is maximal. Limitations in the differential display approach led to the development and optimisation of a subtractive hybridisation approach for use with small amounts of cells or tissue. To focus on cardiac gene expression during the initial phases of heart development, subtractive hybridization was performed between the cardiogenic lateral plate mesoderm of Hamburger and Hamilton stage 4 embryos and the heart primordia of stage 9 embryos. Of the 87 independent clones identified by this procedure, 59 matched known sequences with high homology, 25 matched unknown expressed sequence tag (EST) sequences with high homology, and 3 did not match any known sequence on the database. Known genes isolated included those involved in transcription, translation, cell signalling, RNA processing, and energy production. Two of these genes, high mobility group phosphoprotein A2 (HMGA2) and C1-20C, an unknown gene, were chosen for further characterisation. The role of each gene in early chick heart development and indeed development in general, was addressed using techniques such as in situ hybridisation, transfection analysis, in ovo electroporation and RNAi.
HMGA2 is a nuclear phosphoprotein commonly referred to as an architectural transcription factor due to its ability to modulate DNA conformation. In keeping with this function, HMGA2/GFP fusion protein was shown to localise to the nucleus and in particular, the nucleolus. In situ hybridisation analysis suggested a role for HMGA2 in heart and somite development. HMGA2 expression was first detected at HH stage 5 in the lateral plate mesoderm, a region synonymous with cells specified to the cardiac fate. HMGA2 was also strongly expressed in the presomitic segmental plate mesoderm and as somites developed from the segmental plate mesoderm, the expression of HMGA2 showed an increasingly more restricted domain corresponding to the level of maturation of the somite. Restriction of HMGA2 expression was first detected in the dorsal region of the epithelial somite, then the dorsomedial lip of the dermomyotome, and finally the migrating epaxial myotome cells. The novel intronless gene, C1-20C, predicts a protein of 148 amino acids containing a putative zinc finger binding domain and prenyl binding motif. Zinc binding assays showed that the zinc finger domain of C1-20C/MBP fusion protein bound over six times the quantity of zinc compared to MBP alone, although not in a 1:1 stoichiometric molar ratio. C1-20C/GFP fusion protein was shown to localise to as yet unidentified intracellular cytoplasmic vesicular compartments. These compartments did not colocalise with the endosome/lysosome pathway, aparently ruling out a role for C1-20C in protein trafficking, recycling or degradation. Expression of C1-20C in the chick embryo suggests a possible role in heart and notochord development and preliminary results using siRNA suggest that C1-20C is involved in normal heart looping.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Biomolecular and Biomedical Sciences
Full Text
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Stunden, Carolyn. "Selection for primordial germ cells in the stage X chick embryo using magnetic-activated cell sorting". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ43274.pdf.
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Challen, C. "Studies on the components of the cell-cell extruded cytosolic complex in chick embryo fibroblast cells". Thesis, University of Newcastle Upon Tyne, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234410.
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Gustafsson, Sofia. "Cannabinoids as modulators of cancer cell viability, neuronal differentiation, and embryonal development". Doctoral thesis, Umeå universitet, Farmakologi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-51560.
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Cannabinoids (CBs) are compounds that activate the CB1 and CB2 receptors. CB receptors mediate many different physiological functions, and cannabinoids have been reported to decrease tumor cell viability, proliferation, migration, as well as to modulate metastasis. In this thesis, the effects of cannabinoids on human colorectal carcinoma Caco-2 cells (Paper I) and mouse P19 embryonal carcinoma (EC) cells (Paper III) were studied. In both cell lines, the compounds examined produced a concentration- and time-dependent decrease in cell viability. In Caco-2-cells, HU 210 and the pyrimidine antagonist 5-fluorouracil produced synergistic effects upon cell viability. The mechanisms behind the cytocidal effects of cannabinoids appear to be mediated by other than solely the CB receptor, and a common mechanism in Caco-2 and P19 EC cells was oxidative stress. However, in P19 EC cells the CB receptors contribute to the cytocidal effects possibly via ceramide production. In paper II, the association between CB1 receptor immunoreactivity (CB1IR) and different histopathological variables and disease-specific survival of colorectal cancer (CRC) was investigated. In microsatellite stable (MSS) cases there was a significant positive association of the tumor grade with the CB1IR intensity. A high CB1IR is indicative of a poorer prognosis in MSS with stage II CRC patients. Paper IV focused on the cytotoxic effects of cannabinoids during neuronal differentiation. HU 210 affected the cell viability, neurite formation and produced a decreased intracellular AChE activity. The effects of cannabinoids on embryonic development and survival were examined in Paper V, by repeated injection of cannabinoids in fertilized chicken eggs. After 10 days of incubation, HU 210 and cannabidiol (without CB receptor affinity), decreased the viability of chick embryos, in a manner that could be blocked by α-tocopherol (antioxidant) and attenuated by AM251 (CB1 receptor antagonist). In conclusion, based on these studies, the cannabinoid system may provide a new target for the development of drugs to treat cancer such as CRC. However, the CBs also produce seemingly unspecific cytotoxic effects, and may have negative effects on the neuronal differentiation process. This may be responsible for, at least some of, the embryotoxic effects found in ovo, but also for the cognitive and neurotoxic effects of cannabinoids in the developing and adult nervous system.
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Monahan, Jennifer L. "Skeletal Pathology of Tibiotarsi in Chick Embryos Exposed to Platinum Group Metals by Micro-Raman Spectroscopy". Wright State University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=wright1278554763.
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Khursheed, K. N. "Development of a chick embryo model to study important regulatory domains of human genes implicated in Motor Neurone Disease". Thesis, University of Liverpool, 2016. http://livrepository.liverpool.ac.uk/3012222/.
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Motor neurone disease refers to a group of neurological disorders that result from progressive degeneration of the motor neurones leading to death from respiratory failure within 3-5 years from the onset of symptoms. Amyotrophic lateral sclerosis (ALS) is one of the most common forms of motor neurone disease, and can be described as entailing the involvement of both upper and lower motor neurones. Usually, the disease is obvious and presents as asymmetrical weakness in the limbs and progressive muscular atrophy. Over the last two decades more than 30 genes have been identified as involved in ALS pathology. These include PARK7 and FUS (Fused in sarcoma) which are the subject of this thesis. FUS is a multifunctional protein that has ubiquitous expression and is involved in different steps of RNA processing such as mRNA and miRNA. 10% of ALS cases are heritable and mutation of the FUS gene is found in 3-5% of familial forms of ALS. Therefore the FUS gene is important for it association as a candidate gene that is postulated to be important for ALS, in addition to various types of cancer. Mutations with FUS gene have been found in autopsy samples from the brain and spinal cord of patients with ALS. Understanding the regulation of FUS gene expression may, therefore, give insights into how its stimulus inducible expression may be associated with neurological disorders. My hypothesis is that the evolutionary conserved regions (ECRs) and primate specific retrotransposons of the SINE-VNTR Alu (SVA) are regulatory domains from the human FUS gene and PARK7 genes. Consequently, the aim of this thesis was to develop an in vivo model to validate their regulation. Comparative genomic analysis was used between distant species, utilizing the ECR browser and UCSC browser to identify conserved regions from the FUS gene. It is demonstrated that ECR and SVA, xviii which can drive reporter gene activity in vitro (in the neuroblastoma cell line), are also capable of driving reporter gene expression in the chick embryo neural tube and brain at embryonic day 5. In conclusion, these identified important ECRs from human FUS gene act as regulatory domains. In addition, the SVAs, representing the most recent retrotransposon to enter the human genome also was showed to have regulatory properties in FUS and PARK7 genes. Furthermore, the thesis demonstrates that these elements regulate gene expression in vitro and in vivo. This supports the idea that employment of the chick embryo as a useful and informative model system to analyse mammalian gene regulation.
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Schaeffer, Julia. "The molecular regulation of spinal nerve outgrowth". Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/271632.
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During amniote embryogenesis, the segmented pattern characteristic of the vertebral column appears early during development through the sequential formation of multipotent structures called somites. Somites differentiate subsequently into dermomyotome (giving rise later to skin and skeletal muscles) and sclerotome (giving rise to vertebral bone structures and cartilage). In addition, sclerotomes subdivide following their rostro-caudal intrasegmental boundary into an axon growth-permissive region (anterior half) and an axon growth-repulsive region (posterior half). This binary system instructs motor and sensory axon navigation, as well as neural crest cell migration, to ensure that the peripheral nervous system develops without obstruction by the future cartilage and bones of the vertebral column. Repellent cues are expressed in posterior half-sclerotomes in order to exclude navigating axons from “no-go” areas and restrict their growth to specific exit points of the future vertebral column. Interestingly, similar repellent cues (e.g. Eph/Ephrins) are expressed in the adult central nervous system (CNS) and have been shown to control connectivity and plasticity throughout life. Following brain or spinal cord injury, these repellent molecules are upregulated by reactive astrocytes accumulating at the lesion site, and may impede axon regeneration in this region. In this dissertation, I am presenting the results of a differential gene expression analysis of anterior and posterior half-sclerotomes, based on RNA-sequencing data and using the chick embryo as a model organism. This study led to the identification of molecules, previously uncharacterized in this system, that may play a role in adhesive and mechanical properties of somites and in axon guidance and fasciculation. I focused on the functional analysis of one molecule of the posterior half-sclerotome, the extracellular matrix protein Fibulin-2. To look at its role in the segmentation of spinal axons, I used ectopic misexpression in a subset of segments based on somite electroporation. The width of spinal nerve bundle growth was restricted by Fibulin-2 overexpression in posterior and anterior half-sclerotomes, suggesting a role in sharpening/controlling the path of spinal axon growth. In addition, I showed that this could occur via an interaction with the axon growth repellent Semaphorin 3A. Then I looked at the expression of Fibulin-2 in two models of CNS injury: mouse cerebral cortical stab injury and rat dorsal crush spinal cord injury. In both cases, I observed an increase in Fibulin-2 protein level compared to control. I also used primary cultures of rat cortical astrocytes to show that the expression of Fibulin-2 after inflammatory cytokine-induced activation is increased. Finally, I studied a candidate axon growth repellent previously identified in the laboratory. I explored the hypothesis that this repellent molecule is an O-glycosylated, spliced variant form of a known protein. To characterize this repellent molecule, I used RNA-sequencing data from chick embryonic somites and 2D gel electrophoresis of an astrocytic cell line protein extract. Together, these results suggested that the developing vertebral column and the adult CNS share molecular features to control axon growth and plasticity. This type of study could lead to the characterization of molecular systems that regulate axon growth, and to the identification of novel therapeutic targets in brain or spinal cord injury.
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Pappas, Athanasios C. "Supplementation of broiler breeder diets with selenium and polyunsaturated fatty acids affects the egg, the embryo and the growing chick". Thesis, University of Glasgow, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.425263.
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Brockway, B. E. "Protein disulphide isomerase (E.C.5.4.3.1.) activity in chick embryo tissue : Its relationship with the synthesis of procollagen, a disulphide-bonded protein". Thesis, University of Kent, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.354441.
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Bertacini, Paula Valença. "Material particulado fino presente no ar da cidade de São Paulo promove alterações nas células de Purkinje: um estudo experimental em embrião de galinha". Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/5/5160/tde-24052011-145330/.
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A poluição do ar é associada a diferentes patologias inclusive as que afetam o sistema nervoso central. O objetivo deste estudo foi avaliar o efeito do material particulado fino (PM2,5) da cidade de São Paulo nas células de Purkinje de embriões de galinha. Dose única de PM2,5 em suspensão (1,5 ou 20,0 Pg.100Pl-1) foi injetada em ovos fertilizados de galinha em E0 foram artificialmente incubados por 18 dias (E18). Análises morfométricas no cerebelo foram realizadas em material submetido à reação imuno-histoquímica com anticorpos dirigidos à calbindina (CB), ao fator neurotrófico derivado do encéfalo (BDNF) e à caspase 3 (CAS) para avaliação da densidade de células de Purkinje, de seus dendritos e da taxa de apoptose nestas células. A expressão do BDNF no cerebelo foi determinada pelo método de immunoblotting. A ocorrência de elementos traço e de peroxidação lipídica no cerebelo foi avaliada, assim como a atividade da superóxido dismutase (SOD) e da catalase. Não foram observadas diferenças no desenvolvimento geral e na taxa de mortalidade dos embriões submetidos ao PM2,5 em comparação aos controles. Embora o PM2.5 em suspensão tenha apresentado elevada quantidade de elementos traço, depleção na concentrações de elementos como Cu, Mg, Mn, Se e Zn foi observada no cerebelo dos animais. Comparados ao controle salina, animais submetidos às concentrações de PM2,5 apresentaram diminuição da densidade de células de Purkinje CB+ nos grupos PM2,5 (18% no PM2,51,5 Pg e 23% no grupo PM2,5 20,0 Pg). Aumento de 45% na densidade de dendritos das células de Purkinje no grupo exposto a PM2,5 20,0 Pg foi observado. Redução significativa na expressão de BDNF no cerebelo e também na densidade de células de Purkinje BDNF+ no grupo PM2,5 20,0 Pg foi observada em relação aos controles e ao grupo PM2,51,5 Pg. A ocorrência de células de Purkinje apoptóticas não variou entre os grupos deste estudo da mesma forma em que a peroxidação lipídica e a atividade de SOD também não variaram. Contudo, foi observada maior atividade da catalase no cerebelo dos animais expostos ao material particulado. Conclusão: O material particulado fino da cidade de São Paulo afetou o desenvolvimento embrionário das células de Purkinje no modelo empregado e promoveu a ativação de mecanismos antioxidantes. A composição elementar do material particulado da cidade de São Paulo pode estar associada à perturbação da poda dendrítica nas células de PurkinjeAir pollutants are associated to several diseases including those related to central nervous system. The aim of this work was to evaluate the effect of urban fine particles (PM2.5) in chicken embryo Purkinje cells. A single dose of PM2.5 suspension in two different concentrations (1.5 or 20.0 Pg.100Pl-1) was injected in fresh laid fertilized eggs on E0. Control groups were performed (intact and saline groups). After 18 days of embryo incubation (E18), no differences in general abnormal development and mortality ratio were found between groups. Cerebellar morphometrical analysis for neuronal density, dendritic outgrowth and cellular apoptosis were scored in anti-CB, anti-BDNF and anti-CAS immunelabeled Purkinje cells. Measurements of trace elements, lipid peroxidation, superoxide dismutase and catalase were performed as well. PM2.5 suspensions presented high amounts of metals but the cerebellar tissue presented metal depletion. Compared to control animals (saline group) both PM2.5 doses exposed embryos showed a decreased number of Purkinje cell CB+ (ca. 18% for PM2.5 1.5 Pg and 23% for PM2.5 20.0 Pg) and increased Purkinje cell dendritic branches density in the PM2.5 20.0Pg exposed embryos (ca. 45% for PM2.5 20.0Pg). Interestingly, a significant reduction of Purkinje cell BDNF expression was observed in the PM2.5 20 Pg group embryos when compared to those of the control and PM2.5 1.5Pg groups. No alterations in the number of Purkinje cells CAS+ were observed. The lipid peroxidation and SOD activity showed similar levels in the cerebellar tissue of all experimental groups, although significant higher levels of CAT were detected in PM2.5 20 Pg group cerebella. In conclusion, urban fine particles impair the embryonic development of Purkinje cells in chick embryo model as well promote the antioxidant defense activation. PM2.5 elemental compounds may disrupt the physiological dendritic pruning of Purkinje cells
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Stahler, Adam Christopher. "Micro-Raman Imaging and Hyperspectral Analysis of Tibiotarsi from Chick Embryos Exposed to Sublethal Doses of Platinum Group Metals". Wright State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=wright1347480100.
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Coronato, Nicola [Verfasser], Paul Gottlob [Akademischer Betreuer] Layer i Bodo [Akademischer Betreuer] Laube. "Identification of cellular and molecular signals involved in neural retina specification in the developing chick embryo / Nicola Coronato ; Paul Gottlob Layer, Bodo Laube". Darmstadt : Universitäts- und Landesbibliothek Darmstadt, 2017. http://d-nb.info/1137624752/34.
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