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Thesis (M. S.)--Texas A&M University, 2006. / "Major Subject: Veterinary Anatomy" Title from author supplied metadata (automated record created on Feb. 23, 2007.) Vita. Abstract. Includes bibliographical references.

Thesis (PhD.(Veterinary Anatomy))--University of Pretoria, 2002.

"Major Subject: Veterinary Anatomy" Title from author supplied metadata (automated record created 2010-03-12 12:08:51). Includes bibliographical references.

"Major Subject: Veterinary Anatomy" Title from author supplied metadata (automated record created 2010-03-12 12:08:51). Includes bibliographical references.

Thesis (Ph. D.)--Texas A&M University, 2005. / "Major Subject: Veterinary Anatomy" Title from author supplied metadata (automated record created on Apr. 14, 2006.) Vita. Abstract. Includes bibliographical references.

The aim of this study was to investigate the components of the ovary in the sexually immature ostrich by using immunohistochemistry, light microscopy and electron microscopy. The light and electron microscopic studies carried out, revealed that the oocyte in the sexually immature ostrich is surrounded by seven layers which included the zona radiata,lamina perivitellina, stratum granulosum, basal lamina, thecal layers (theca interna and theca externa), connective tissue layer and superficial epithelium (see details in Chapter Two and Three). Several morphological and immunohistochemical changes occurred as the follicles developed and regressed, suggesting that ovarian follicles in the sexually immature ostrich undergo a cycle of growth and degeneration as reported in other avian species. In the present study, thecal gland cells in the ovary of the sexually immature ostrich were common. In addition, interstitial gland cells were a notable feature in atretic follicles as described in the ovary of the crow, common myna and dove (Guraya and Chalana, 1976). Further investigations on the interstitial gland cells will provide an insight into the process of steroidogenesis in the sexually immature ostrich. As discussed in Chapter five, various cells in the ovary showed immunoreactivity to oestrogen, progesterone and androgen receptors. These observations indicated that the ovarian tissue in the sexually immature ostrich is a potential target for gonadal hormones. Thus, it can be assumed that steroid hormones regulate ovarian functions in the ostrich. The use of immunohistochemical procedures proved to be an excellent method to investigate the distribution of nerves in the ovary. The results of this study have shown that the ovary in the sexually immature ostrich is well-innervated. However, further studies are required to differentiate between cholinergic and adrenergic nerve fibres. / Dissertation (MSc(Anatomy and Physiology))--University of Pretoria, 2005. / Anatomy and Physiology / unrestricted

This thesis focuses on the study of heparanase which is an enzyme involved as a molecular determinant of cancer metastasis. The purpose of this study was to first quantitate heparanase mRNA levels in both normal and tumorigenic samples from the same tissue specimen. Laser capture microdissection was used in the isolation and extraction of melanoma cell populations from normal tissue. There was a 29 fold upregulation of heparanase expression, detected by real-time PCR, in metastatic melanoma of the lung in comparison to normal lung tissue in mice. Immunohistochemistry (IHC) showed stronger staining in human metastatic melanoma when compared to primary melanoma tumors. IHC also showed a propensity for darker heparanase staining around blood vessels and vascular regions. These results further emphasized the importance of heparanase in invasive and angiogenic mechanisms in melanoma. Once heparanase was determined to be upregulated in melanoma tissue in vivo both at the mRNA and protein level, the next part of this thesis was directed to the development of an orthotopic brain slice model. A novel model that would provide a relatively efficient way to study the biological relevance and mechanisms involved in the invasive process of brain metastatic melanoma and the role that heparanase plays in this invasive process. We showed that this model could be used to determine invasion into brain tissue at both qualitative and quantitative levels. We showed that HPSE-1 augmented invasion of brain metastatic melanoma cells into brain tissue. We also showed that melanoma cells show a time dependent expression of heparanase while invading into brain tissue. Thus, we showed that heparanase is involved in cancer metastasis development and could have important implications in the development of potential drugs aimed to combat cancer metastasis.

Degenerative joint disease, or osteoarthritis, is a major cause of lameness and morbidity in horses, humans, and dogs. There are no truly satisfactory cures for this widespread problem and current treatments all have limitations or unwanted side effects. New cell-based strategies to repair joint surface lesions have generated a high level of interest, but have yet to achieve the full restoration of articular cartilage structure and function. Currently used therapy cells include autologous chondrocytes and adult mesenchymal cells such as bone marrow derived cells and adipose derived cells. Unfortunately, the resultant repair tissue is biomechanically inferior fibrocartilage. A critical gap in knowledge in this regard is a limited understanding of the specific cellular phenotype of normal, robust articular chondrocytes. This thesis examines the global mRNA transcriptome of equine articular cartilage to test the hypothesis that adult articular chondrocytes have a unique gene expression profile. In the first part of the study, RNA-sequencing was used to compare the mRNA transcriptome of normal adult articular cartilage with five other cartilaginous tissues. From these comparisons, locus level gene expression and alternative splicing patterns have been identified that clearly distinguish articular cartilage. In the second part of the study, fetal (interzone, cartilage anlagen chondrocytes, dermal fibroblasts) and adult (bone marrow derived, adipose derived, articular chondrocytes, dermal fibroblasts) primary cells were grown in culture and stimulated to differentiate into chondrocytes. The chondrogenic differentiation potential as assessed by matrix proteoglycan and the expression of cartilage biomarker genes was highly variable among cell types. Together, these results advance our understanding of the specific phenotype of articular chondrocytes and the potential of prospective therapeutic progenitor cells to differentiate into articular chondrocytes. This new knowledge will improve efforts to optimize cell-based therapies for osteoarthritis and the repair of joint cartilage lesions.

Dwarfism is considered one of the most recognized congenital defects of animals and humans and can be hereditary or sporadic in cause and expression. There are two general morphologic categories within this vastly diverse disease. These categories are disproportionate and proportionate dwarfism and within each of these there are numerous phenotypes which have been extensively described in humans, and to a lesser extent in dogs, cattle, mice, chickens, and other domestic species. Ponies and Miniature horses largely differ from full size horses only by their stature. Ponies are often defined as those whose height is not greater than 14.2 hands; however the maximum height for Miniature horses is constitutionally defined as 8.2 hands. Dwarfism is not considered a desirable genetic trait for Miniature horses. A majority of these conformationally inferior horses showed consistent physical abnormalities typical of disproportionate dwarfisms as seen in other mammal species. A whole genome scan with the Illumina Equine SNP50 chip clearly implicated a region on ECA1 as being associated with dwarfism of horses. The region implicated on the horse chromosome 1 (Equus Caballus; ECA1) contained a candidate gene for dwarfism, aggrecan (ACAN). Mutations were found in Exons 2, 6, 11 and 15 with each mutation associated with a distinct type of dwarfism. These mutations are independently transmitted throughout the population. Absence of normal homozygotes for these mutations and absence of normal horses which were heterozygous for these mutations indicated that these alleles caused dwarfism in those genotypes. These genotypes did not explain all observed dwarves in this population.