Thesis (Ph.D.)--University of Alberta, 2010. / A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Experimental Surgery, Department of Surgery. Title from pdf file main screen (viewed on February 17, 2010). Includes bibliographical references.

Much of this thesis describes the use of immunohistochemical methods on salivary glands from patients with Sjogren's syndrome (SS) to quantify the position, nature and proliferative activity of the inflammatory cell infiltrate, deposition of cell matrix proteins and glandular expression of TGFp. Studies are also undertaken on glands from an experimental animal model and from patients with two associated conditions, benign lymphoepithelial lesion (BLEL) and systemic sclerosis (SSc). Initially a rat model of SS was examined and changes in salivary glands quantified at different stages after autoimmunisation. Immunohistochemically there were similarities to SS, in that class II antigen was expressed by glandular epithelium and the early lesions contained T lymphocytes. However, B lymphocytes were rare, the cell infiltrate contained large populations of macrophages and neutrophils, and there was evidence of increased elaboration of fibrous connective tissue. These results indicate that this animal model is of doubtful use for the study of Sjogren's syndrome. Studies on human tissue showed that the lymphocyte infiltrate in BLEL patients was more extensive than SS and that T cells predominated in small foci, whereas B cells were the dominant lymphocyte type in larger foci. In areas of extensive lymphocyte infiltration, B cells were closely associated with ducts or present in germinal centre-like structures with T cells being found elsewhere. A previously unreported feature of BLEL was the presence of intra-epithelial (and intra-lumenal) B cells, many of which were proliferating. The remaining duct walls in BLEL appeared to be under pressure due to this population of B lymphocytes and "holes" were observed both in the basement membrane and at the lumenal surface that may facilitate migration of lymphocytes from glandular stroma into duct lumens. There was significantly more tenascin and fibronectin in BLEL glands (p<0.01) compared to normal parotid controls which contained minimal amounts of these proteins. By contrast, both proteins were expressed in normal labial glands with no significant increase in glands from SS and SSc patients. As both tenascin and fibronectin are important in cell migration, increased levels may be a factor facilitating lymphoid infiltration in BLEL. Absorbance measurements demonstrated that ductal expression of TGFI differed between control, SS and BLEL salivary glands. SS glands showed an increase in expression of all isoforms of TGFß with the increase for TGFP2 and TGFP3 being significant (p=0.02 & p<0.002). By contrast, ductal expression of all isoforms of TGFI in BLEL was reduced in both confluent (p<0.0001) and minimally infiltrated (p<0.005) areas of gland. Thus reduced glandular expression of TGFJ may be important in allowing the high levels of lymphocyte and epithelial cell proliferation detected in BLEL which are rarely seen in SS. Salivary glands from SSc and Raynaud's phenomenon (RP) patients contained small, predominately T cell foci with few proliferating B cells and a significantly increased mast cell population (p<0.005). Fibrosis within the glands was variable and not associated with increased deposition of fibronectin or tenascin. Subjectively, the most obvious difference in TGFI expression in SSc compared to controls was exhibited by fibroblasts. Cell counts revealed no differences in fibroblast expression of TGFßI or TGFß receptors. However, the percentage of TGFß2-positive fibroblasts was significantly higher in SSc glands compared to controls (p<0.004). RP glands showed an intermediate level of expression. By contrast, a lower percentage of RP fibroblasts expressed TGF(33 compared to controls, with SSc glands showing an intermediate level of expression. The results indicate that both SSc and RP are associated with an increased salivary gland mast cell population and changes in expression of TGFß2 and ß3 isoforms by glandular fibroblasts. The final section of this thesis describes an investigation of antioxidant levels in saliva from healthy individuals and patients with SS or periodontal disease. The results demonstrated that in SS there was an increase in the concentration of antioxidants in unstimulated saliva but a reduced rate of production. This diminished output of salivary gland antioxidants may be of significance to the oral health of these patients. In periodontal disease there was a reduction in antioxidant levels in stimulated saliva that may have been the result of local depletion by reactive oxygen species, produced by chronic inflammation within the gingival tissues. Alternatively, these patients may have intrinsically reduced levels of antioxidants and therefore be more susceptible to periodontal disease.

published_or_final_version / Medical Sciences / Master / Master of Medical Sciences

published_or_final_version / Pathology / Master / Master of Philosophy

Voltage-dependent channels on the dendrites of motoneurons provide additional current that amplifies or dampens synaptic current en route to the soma. The specific consequences will depend on the density and distribution of the voltage-dependent channels. HCN channels generate a positive inward current in response to hyperpolarization. HCN channels are responsible for a resonance phenomenon in motoneurons where inputs of certain frequencies are preferentially amplified. Modelling studies indicate that this resonance behaviour only occurs if HCN channels are uniformly distributed on the dendritic tree. However, the distribution of HCN channels on the dendrites of motoneurons is unknown. Furthermore, current techniques for measuring channel density on dendrites suffer from methodological limitations that prevent sampling on a scale necessary to map the distribution of voltage-dependent channels across the dendritic tree. The goal of the present study is to develop a high throughput method for measuring the membrane-associated density of voltage-dependent channels using immunohistochemical, confocal and three-dimensional image analysis techniques. Secondly, the proximal to distal distribution of membrane-associated channels formed by the HCN1-subunit on the dendritic trees of trapezius motoneurons in the adult feline will be compared. Antidromically identified motoneurons innervating the trapezius muscle were intracellularly stained in order to visualize the entire dendritic tree. HCN1-subunit containing channels were labeled with a specific antibody. Dendritic segments (n=27 to 92) of ten trapezius motoneurons at different distances from the soma were acquired using confocal microscopy and rendered into a three-dimensional volume. The perimeter of the intracellular stain was used to define the membrane-cytoplasmic border. Analysis of the HCN1 immunoreactivitywas constrained to this perimeter. This technique provides a means of extracting membrane-associated HCN1 labeling and therefore the functional distribution of HCN1 channels. The density of membrane-associated HCN1 immunoreactvity across the dendritic tree was either uniform or increased with distance from the soma among the ten trapezius motoneurons. The increase in HCN1 density with distance from the soma was inversely related to the density of HCN1 on the soma and proximal dendrites. Lastly, the change in HCN1 density with distance from the soma was inversely related to the total input conductance of the motoneuron. / Thesis (Master, Neuroscience Studies) -- Queen's University, 2012-08-01 13:59:32.403

Diss. Linköping : Linköpings universitet, 2007.

Thesis (M.S.)--University of Missouri-Columbia, 2007. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on January 3, 2008) Includes bibliographical references.

Thesis (D.Phil (Zoologyy ))--University of Pretoria, 2002. / Includes abstract in English. Includes bibliographical references.

Thesis (M. Med. Sc.)--University of Hong Kong, 2006.

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