High-dose morphine has been extensively used in the control of postoperative and cancer pain. Patients receiving prolonged administration of high-dose morphine are known to be associated with certain cardiovascular complications and tissue regeneration defects. This research thesis aims to investigate the biological effects and molecular mechanisms of high-dose morphine on the vascular endothelial function, angiogenesis and wound regeneration using murine models of morphine-dependence and cultured endothelial cell assays. Mice were subjected to placebo or morphine (20 mg/kg, i.p.) injection for consecutive 14 days. Aortas were harvested for assessment of vasomotor function by isometric force recordings. Protein expression p47phox (a major subunit of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase) was determined by Western blotting. Generation of superoxide anions was detected under confocal microscope. Endothelium-dependent relaxations to acetylcholine were significantly reduced in morphine-treated animals, but were normalized by superoxide scavenging. Fluorescent densities of dihydroethidium and expression of p47phox were increased in the aorta of morphine-treated mice. In the second part of this thesis, the candidate determined the effects of high-dose morphine on angiogenesis and mobilization of endothelial progenitor cells (EPCs) in a mouse model of excisional wound injury. Excisional wound was created on control and morphine-dependent mice. Wound healing was compared by measuring the final-to-initial wound area ratio. Generation of superoxide anions in the wound was determined by luminol-enhanced chemiluminescence. Circulating mononuclear cells were isolated and measured for EPC (defined as CD34+/CD133+ cell) counts. In vivo and in vitro measurements of angiogenesis following morphine treatment were performed using the Matrigel assay. The results showed that wound closure was significantly reduced in mice treated with morphine when compared with controls, and higher levels of superoxide anions were generated in these wounds. High-dose morphine reduced numbers of circulating EPCs following creation of excisional wound. Matrigel assay showed impaired angiogenesis in animals and reduced capillary tube formation in cultured endothelial cells treated with high-concentration of morphine. Collectively, this research thesis demonstrated a number of novel findings. First, high-dose of morphine impairs vascular endothelial function by increased production of vascular superoxide anions. Activation of NADPH oxidase may be the molecular mechanisms responsible for reduced bioavailability of endothelium-derived NO. Second, systemic administration of high-dose morphine delays healing of excisional wounds and impairs angiogenesis. This antiangiogenic effect is associated with increased superoxide anions production and impaired mobilization of EPCs. In line with direct endothelial dysfunction, impaired angiogenesis and EPC mobilization resulted from high-dose morphine treatment may cause increased cardiovascular morbidity in human subjects receiving higher therapeutic dose of morphine.

Thesis (Ph. D.)--Case Western Reserve University, 2004. / [School of Medicine] Department of Neurosciences. Includes bibliographical references. Available online via OhioLINK's ETD Center.

Thesis (Ph. D.)--University of Washington, 2003. / Vita. Includes bibliographical references (leaves 198-210).

Zugl.: Berlin, Freie Univ., Diss., 2008 / Includes bibliographic references.

published_or_final_version / Pharmacology / Master / Master of Philosophy

No description available.

This work helps to determine the extent of immune system involvement in the adaptive response to subacute ruminal acidosis (SARA) in three parts. The first (Chapter 2) uses non-lactating cows to study specific changes in inflammatory protein expression in which SARA is created. The second (Chapter 3), uses the same model as Chapter 2. However, in this case, lactating cows are used to help establish the time course for adaptation to acidosis. The third part (Chapter 4) delineates the genomic changes that occur in the rumen epithelium when a therapeutic intervention is introduced using exogenous supplemental butyrate. In the first experiment, the expression of the extracellular matrix (ECM) proteins type IV collagen and laminin β1 decreased, and the monocarboxylate transporter MCT1, increased during the acidotic challenge. Nuclear factor of activated T-cells, NFATc2, and tumour necrosis factor alpha (TNF-α) decreased while interleukin-1 beta (IL-1β) increased during the experimental treatment period. Chapter 3 measured lipopolysaccharide (LPS) and its carrier, LPS binding protein, LBP, which were found to be elevated due to SARA. Moreover, NFATc2 was reduced during this period. Exogenous butyrate resulted in increased plasma LBP, plasma beta hydroxyl butyrate (BHBA), and ruminal butyrate. Milk parameters (total protein and fat) were unaffected by treatment, as were rumen LPS, acetate, valerate, isovalerate, and isobutyrate. Moreover, exogenous butyrate increased gene transcription of genes involved in non-specific host defences (NHSD) such as mucin, and remodelling (RM), such as matrix metallopeptidase 16 (MMP16), and decreased the transcription of genes of the immune response (IR), such as nuclear factor kappa B2 (NFκB2). Together, these three experiments have demonstrated that although wound healing is mediated by the immune system in more severe models of epithelial damage, our model of SARA did not involve full-thickness, penetrating lesions and hence did not involve the systemic immune system to such a degree than was previously thought. In addition, we were able to demonstrate that the addition of butyrate to this model of grain-induced acidosis was beneficial, as it decreased the local inflammatory response and helped the epithelium adapt to its harsher environment. / Agriculture and Agri-Food Canada, the National Sciences and Engineering Council of Canada (NSERC), the Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA), the Canadian Dairy Commission (CDC), and the Dairy Farmers of Ontario (DFO).

Introduction Keloids are formed by the excessive production of scar tissue, which extends beyond the margins of the original injury, often resulting in lesions of grotesque dimensions. Keloids present a major dilemma to surgeons because of the high recurrence rate with recurrent growth often larger than the original keloid. The high recurrence rate and the poor response of keloids to therapy present a great challenge to surgeons. The numerous therapeutic regimens demonstrate that to date there is no single therapy that is absolutely successful. Therefore, it is necessary to comprehensively establish the pathology of keloids and to determine the aetiopathogenesis of the lesion in order to eventually provide unfailing specific effective treatment and to better understand the mechanisms regulating fibrosis in various fibroproliferative diseases. Aim To evaluate the pathology and aetiopathogenesis of keloid formation. Methods The research protocol for the study was approved by the Nelson R Mandela Faculty of Medicine Ethics Committee. Informed consent was obtained before the biopsies were taken. Keloid and non-lesional skin biopsies were obtained from thirty two patients who had multiple lesions in various locations, bringing the total number of keloids and apparently normal skin biopsies processed and examined to fifty eight. The biopsied specimens were processed for paraffin wax embedment and routine haematoxylin and eosin, differential and immunocytochemical staining. Sections were scrupulously examined using the Olympus BH-2 microscope; features pertinent to the study were photographed with the Olympus DP 10 microscope digital camera system. The stored images were studied, using the Camedia graphics processing programme. Results The results of the study showed that keloids comprise many distinct regions categorized as: the zone of hyalinising collagen bundles, fine fibrous areas, areas of inflammation, zone of dense regular connective tissue, nodular fibrous area and area of angiogenesis. Fibroblastic phenotypes present ranged from spindle, fibrohistiocytic, epitheloid, elongated flattened condensed fibroblastic cells to few wavy, fuzzy, polygonal and atrophic cell types. Immunocytochemically these cells were vimentin-positive and actin- and desmin-negative. Few myofibroblastic phenotypes were also identified and these were vimentin- and alpha smooth muscle actin-positive and desmin-negative. The fibroblastic and myofibroblastic phenotypes were in proliferative or degenerative stages and pathological features exhibited were the presence of vesicular, degenerate or calcified nuclei; nuclear and plasma membrane damage; cytoplasmic and nucleoplasmic clearing; atrophy, pyknosis and swelling. Severe, moderate to mild paravascular inflammation was observed around the microvessels of the sub-papillary plexus and within the keloid. There was compression and occlusion of small blood vessels, coagulation necrosis and dissolution of mural cells of small blood vessels and small peripheral nerves. Also present in keloids were oedematous areas, disorganised and hyalinised connective tissue fibres and increased numbers of degranulated and degranulating mast cells. Elastic fibres in keloids were minimal or absent whereas at the border of keloids there was an increase.Discussion Degenerate, occluded and compressed microvessels were a widespread pathological feature in keloids. This resulted in impaired vascular supply to each of the keloid regions which impacted directly on the pathology of keloids where degeneration and necrosis, manifesting the lack of nutrients and oxygen to tissue, were found throughout the keloid. The vascular supply was impaired because of the chronic inflammatory destruction of the microvessels and the elevated stress within keloids. Factors contributing to increased intrinsic stress were: 1) the lack of elastic fibres in keloids which decreased the elastic limit, leading to effects of excessive deformational force which were compression and stiffening of tissue; 2) the high tension skin covering keloid prone areas had low stretch and a low elastic modulus; 3). protruding hard connective tissue such as bony prominences or cartilage into the dermis of keloid prone skin; 4) contractile forces exerted by wound healing fibroblastic cells; and 5) external forces. Compression and occlusion of blood vessels induced ischaemic and reperfusion tissue injury. During the reperfusion phase blood rich in growth factors returned to tissue stimulating tissue growth. Tissue growth was also promoted by elevated internal stress which stimulated increasing levels of gene expression, collagen synthesis and mitotic activity. All these growth promoting effects resulted in keloid formation. / Thesis (Ph.D.)-University of KwaZulu-Natal, Durban, 2013.

The mechanisms responsible for the healing of corneal surface wounds are the subject of biological controversy. In particular, the role and source of the regulatory chemical epidermal growth factor (EGF) is an area of intense debate. In the first part of this thesis, we propose a reaction-diffusion model which focuses on the stimulus for increased mitotic and migratory activity due to secretion of EGF. A detailed numerical study of various possible models, with parameter values based on biological data, reveals that, for realistic healing times, EGF must be released by the underlying layers of the cornea, in addition to the tear film source. The model exhibits travelling wave solutions and further analysis elucidates the interaction and role of the parameters in determining the speed of healing. Furthermore, we consider the effect of topical application of EGF and investigate the effect of curvature of the eye. We show that our model is consistent with many of the key features of corneal wound healing. Adult dermal wounds, in contrast to foetal wounds, heal with the formation of scar tissue. A crucial factor in determining the nature of the healed tissue is the ratio of collagen 1 to collagen 3, which indicates the fibril diameter. We develop a reaction-diffusion model which focuses on the stimulus for collagen synthesis due to the secretion of the different isoforms of the regulatory chemical transforming growth factor β (TGFβ). Numerical simulations of the model without diffusion lead to a value of this ratio consistent with that of healthy tissue for the foetus but corresponding to scarring in the adult. The model equations evolve to waves moving into the wound, but addition of TGFβ only has a transient effect on the final collagen levels. We investigate this effect by developing a caricature model. The model indicates that the main source of the fibroblasts is the underlying subcutaneous tissue and we determine key parameters which explain the difference between adult and foetal wound healing. Furthermore we make clinically testable predictions on the effects that topical application of various chemicals will have on scar formation.

Thesis (M.S.)--University of Alabama at Birmingham, 2007. / Additional advisors: Dale S. Feldman, Mary J. MacDougall, Laura Timares. Description based on contents viewed Feb. 4, 2008; title from title screen. Includes bibliographical references (p. 39-40).