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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

Optimizing Endothelial Repopulation of Decellularized Lung

Stabler, Collin Turner January 2016 (has links)
Decellularized lung tissue has been recognized as a potential platform to engineer whole lung organs suitable for transplantation or for modeling a variety of lung diseases. However many technical hurdles remain before this potential may be fully realized. Inability to efficiently re-endothelialize the pulmonary vasculature with a functional endothelium appears to be the primary cause of failure of recellularized lung scaffolds in early transplant studies. This dissertation research aims to enhance the re-endothelialization of decellularized rodent lung scaffolds with rat lung microvascular endothelial cells. This was achieved by adjusting the posture of the lung to a supine position during cell seeding through the pulmonary artery. The supine position allowed for significantly more homogeneous seeding and better cell retention in the apex regions of all lobes than the traditional upright position, especially in the right upper and left lobes. Additionally, the supine position allowed for greater cell retention within large diameter vessels (proximal – 100 µm to 5,000 µm) than the upright position, with little to no difference in the small diameter distal vessels. Endothelial cell adhesion in the proximal regions of the pulmonary vasculature in the decellularized lung was dependent on the binding of endothelial cell integrins, specifically α1β1, α2β1 and α5β1 integrins to, respectively, collagen type-I, type-IV and fibronectin in the residual ECM. Following in vitro maturation of the seeded constructs under perfusion culture, the seeded endothelial cells spread along the vascular wall, leading to a partial re-establishment of endothelial barrier function as inferred from a custom-designed leakage assay. The results of this dissertation research suggest that attention to cellular distribution within the whole organ is of paramount importance for restoring proper vascular function. / Bioengineering
72

The role of NKT cells following solid organ transplantation

Gieschen-Krische, Mary January 2014 (has links)
Introduction: NKT cells are categorised as borderline between NK and T cells, sharing phenotypic and functional characteristics of both cells, demonstrating their capacity to contritube to both pro- or anti-inflammatory processes. However, the role of these cells among lung transplant recipients remains largely unknown. The aim of this study was to determine the role of NKT cells following lung transplantation. Methods: NKT cells were quantified and characterised according to markers of: activation (CD107a, CD161, NKG2D) and immunomodulation (CD200 and CD200R) in peripheral blood and BALs. NKT cell numbers and phenotypes were correlated to clinical variables: immunosuppression, acute rejection, acute infections (viral, bacterial and fungal), bronchiolitis obliterans syndrome (BOS grade), lung function, and demographic variables. Interactions between NKT cells and the transplanted lung were linked by determining the relative expression of immunomodulatory ligand CD200 in lung biopsies. In vitro models were employed to determine the role of NKT cells to acute lung injury, either alone or in combination with cells of the mononuclear phagocyte system (MPS). Results: Higher numbers of immunomodulatory NKT cells (CD200+ and CD200R+) were found as lung function decreased. Data from peripheral blood indicates that recipients whose donors or themselves had been exposed to CMV infection demonstrated increased numbers of NKT cells. Patients with active EBV infections demonstrated higher NKT cell numbers expressing CD200 and CD200R. Data from BALs, indicates that patients with active fungal infections present higher immunomodulatory (CD200R) NKT cells and lower cytotoxicity marker (CD107a). In peripheral blood, lung recipients demonstrated higher NKT cell numbers compared to healthy volunteers. However, the lower relative mean expression of functional markers in the lung transplant group suggests that cells are less active. In vitro cultures with immunosuppressants demonstrated that cell cycle inhibitors (MMF and AZA) and corticosteroids (Prednisolone) are likely to inhibit NKT cell proliferation, while calcineurin inhibitors (Cyclosporine A and Tacrolimus) decrease the relative mean expression of activation markers. Clinical observations indicate that higher doses of Azathioprine may correlate with increased NKT cell numbers and the relative expression of CD200 and CD200R. However, under these conditions the relative expression of activation marker NKG2D decreases. In vitro data from the acute injury model indicates that NKT cells are capable to migrate into the injured lung and become activated following transmigration which is facilitated by the presence of monocytes. We also observed the interaction of NKT cells with endothelial cells, monocytes and macrophages. Also, the relative mean expression of CD200 and CD200R increased at the capillary layer, regardless of injury while upregulation of activation markers (CD107a, CD161 and NKG2D) was found at the capillary layer, following injury. In contrast, the alveolar layer demonstrated a decrease in both activation and immunomodulatory markers, following acute injury. Conclusions: Despite immunosuppression, NKT cells remain present in peripheral blood and BAL following lung transplantation. NKT cell proliferation is likely to be reduced by effect of cell cycle inhibitors, while calcineurin inhibitors exert an immunomodulatory effect. Our data indicates that NKT cells can participate in inflammatory and immunomodulatory events at the alveolar bilayer. Their capacity to infiltrate the lungs was assisted by cells of the mononuclear phagocyte system (MPS), which play an important role in antigen presentation and modulation of acute injury. Further research is needed to elucidate the signals and mechanisms occurring between NKT and MPS interactions and the outcomes these populations drive in acute lung injury.
73

Change in lung volume in asthma with particular reference to obesity

Schachter, L. M January 2005 (has links)
Doctor of Philosophy(PhD) / Over the last 20 years both asthma and obesity have increased in prevalence. What is the link? There are data to suggest that increasing obesity is a risk for the increase in prevalence of asthma. A number of mechanisms have been postulated including the effects of reduced lung volume on bronchial reactivity and mechanical changes with lower lung volumes. Other possibilities include other obesity-induced co-morbidities including gastro-oesophageal reflux. The aim of this thesis was to evaluate the link between asthma and obesity in both adult and childhood populations and to undertake experimental studies to examine the effects of changes in lung volume on bronchial reactivity. In chapter 1, the literature is reviewed. The current literature suggests that there is a link between diagnosis of asthma, new onset of asthma, symptoms of shortness of breath and wheeze. In chapter 2, data on 1997 adults in 3 population studies were analysed and the association between body mass index (BMI) and symptoms of shortness of breath and wheeze, diagnosis of asthma, medication usage for asthma, lung function and bronchial responsiveness were studied. This study showed that obesity was a risk for recent asthma (OR 2.04; 95%CI 1.02-3.76, p=0.048), symptoms of shortness of breath and wheeze (OR 2.6; 95%CI 1.46- 4.70, p=0.001), and medication usage for asthma (OR 2.53; 95%CI 1.36-4.70, p=0.003). There was a reduction in lung volume as measured by forced vital capacity (FVC), but there was no increase in bronchial hyperresponsiveness (BHR) (OR 0.87; 95% CI 0.35-2.21, p=0.78). Thus although the symptoms of asthma are increased there were no increases in BHR, despite significantly reduced lung volumes. The increase the medication usage is unlikely to have normalised the BHR, as there were ongoing symptoms suggestive of asthma. In chapter 3, data on 5993 children in 7 population studies were analysed and the association between BMI percentile and symptoms of cough, wheeze, ix diagnosis of asthma, medication usage for asthma, atopy, lung function and bronchial responsiveness was studied. After adjusting for atopy, sex, age, smoking and family history, BMI was a significant risk factor for wheeze ever (OR=1.06; 95%CI 1.01-1.10, p=0.008) and cough (OR=1.09; 95%CI 1.05-1.14, p=0.001) but not for recent asthma (OR=1.02; 95%CI 0.98-1.07 p=0.43), or bronchial hyperresponsiveness (OR=0.97; 95%CI 0.95-1.04 p=0.77). In girls, a higher BMI was significantly associated with higher prevalence of atopy (x2 trend 7.9, p=0.005), wheeze ever (x2 trend 10.4, p=0.001), and cough (x2 trend 12.3, p<0.001). These were not significant in boys. With increasing BMI in children, there was no reduction in lung volume, no increase in airway obstruction and no increase in bronchial responsiveness. In chapter 4, the hypothesis that obesity per se is associated with bronchial responsiveness was tested. Six obese women without asthma were compared to 6 non-obese women without asthma with high dose methacholine challenges to assess the bronchial responsiveness. There was no increase in bronchial responsiveness, and no difference in the position or shape of the high dose methacholine curve despite the fact that these women had reduced lung volumes associated with their obesity. In chapter 5, the hypothesis whether reduced lung volume per se would cause a change in greater mechanical effect, ie more marked airway narrowing in both non-asthmatic and asthmatic subjects was tested. Lung volumes and methacholine challenges were undertaken in the supine and erect position on different days. As expected in normal subjects there was a small reduction in lung volume on lying down, this was associated with an increase in the measure of bronchial reactivity DRR. In contrast, in asthmatics, there was no acute fall in lung volume and there were variable changes in the index of reactivity suggesting non-homogeneity in the lung function abnormality. This suggests changes in bronchial reactivity can occur without any relationship to lung volume change. These negative results suggest that lung volume changes that may occur in obesity are unlikely contributors to the apparent increase in asthma symptoms. In chapter 6, the hypothesis that the supposed increase in asthma symptoms in the obese were due to the effects of gastro-oesophageal reflux were assessed in 147 obese subjects graded for gastro-oesophageal reflux severity using manometry and gastroscopy. This study showed that subjects with increased gastro-oesophageal reflux did not have subjective increases in asthma prevalence, obstructive sleep apnoea, or snoring however they had a clear worsening of gas transfer as measured by carbon monoxide transfer suggesting a greater level of parenchymal disease. The overall results are that there is an increase of diagnosis of asthma, increase in symptoms of asthma and medication usage for the treatment of asthma in the obese. Objectively despite reductions in lung volume, there is no increase in bronchial responsiveness in this group suggesting that these symptoms are not related to true asthma, but to alternative co-morbidities associated with obesity such as gastro-oesophageal reflux. Notably gastrooesophageal reflux was not associated with increased asthma prevalence or airway obstruction. However it was associated with reduced gas transfer suggesting parenchymal disease. This suggests that the increase in symptoms of wheeze and shortness of breath in the obese should not be attributed to asthma in the absence of variable airflow limitation that is reversible spontaneously or with treatment, or with an increase in the existing bronchial hyperresponsiveness (BHR) to a variety of stimuli.
74

Recovery following pneumonectomy: patients initial 2 year experience

McLean, Jocelyn Margaret January 2003 (has links)
Little is known about the recovery of patients after pneumonectomy and the impact of the surgery on the lifestyle of young, employed, ex-smokers and their families. This study was conducted to address this knowledge deficit, and gather information that would help health professionals to be able to assist people facing pneumonectomy. A qualitative study using van Manens methodological approach to interpretive phenomenology was chosen, in order to capture a full and rich understanding and meaning of the phenomenon that patients live. The names, age, operation, histological cell type, stage of disease, and disease free status of potential participants were obtained from a Lung Cancer Surgical Database after obtaining ethical approval for the study. Nine participants (three females and six males) met the inclusion criteria and gave informed consent for the study. Data collection comprised of open-ended interviews that were audiotaped, then transcribed verbatim into hard data. Data interpretation was based on the selective reading approach of van Manen from which six thematic statements arose. These are living the discomforts of treatment and recovery, discovering new limitations on myself; functional and emotional, my reliance on support, my financial security is threatened, my survival is at threat, and I wish I had known more. The study found that each participant had a unique experience of recovery and consequently the degree of recovery attained varied between participants. They all had a very strong desire to survive lung cancer and considered the risks of major surgery and loosing a lung to be insignificant compared to the certainty of loosing their life if they did not undergo surgery. This study provided a glimpse of what it was like for a group of patients to live the experience of life after a pneumonectomy and it provides a basis from which nurses can explore further the experiences of patients who are subjected to lung cancer surgery.
75

Effects of a reformulation of prioritized objectives upon the attitudes and composition of a professionally-oriented, volunteer governing body within an agency of the "Third Sector" a case study /

Godino, Frank C. January 1982 (has links)
Thesis (M.P.A.)--Kutztown State College, 1982. / Source: Masters Abstracts International, Volume: 45-06, page: 2942. Typescript. Abstract precedes thesis as preliminary leaves 1-3. Includes bibliographical references (leaves 74-79).
76

Investigation of the Oncogenic Role of Sox2 in the Pathogenesis of Lung Squamous Cell Carcinoma using Normal Human Lung Basal Progenitors

Kim, Bo Ram 21 March 2012 (has links)
Sox2 is the most frequently amplified oncogene in lung squamous cell carcinoma (SCC). Lung SCC arises in the proximal to central airways and is thought to originate from the p63-positive basal progenitor cells. Since Sox2 amplification occurs early in SCC pathogenesis, we investigated the oncogenic role of Sox2 using normal primary human lung basal progenitor cells. Although Sox2 is highly expressed in normal basal progenitors in a quiescent tracheal epithelium in vivo, we found that Sox2 expression decreases substantially during in vitro proliferation. When Sox2 expression is elevated in the proliferating basal cells in vitro to a level clinically observed in lung SCCs, Sox2 causes hyperplasia and promotes both squamous and Mucin16-positive glandular lineages at the expense of ciliated cell differentiation. Furthermore, our data suggest that the squamous and glandular-differentiating activity of Sox2 is differentially modulated by Receptor tyrosine kinase (RTK) and/or PI3-kinase signaling to promote squamous metaplasia of basal progenitor cells during SCC development.
77

Investigation of the Oncogenic Role of Sox2 in the Pathogenesis of Lung Squamous Cell Carcinoma using Normal Human Lung Basal Progenitors

Kim, Bo Ram 21 March 2012 (has links)
Sox2 is the most frequently amplified oncogene in lung squamous cell carcinoma (SCC). Lung SCC arises in the proximal to central airways and is thought to originate from the p63-positive basal progenitor cells. Since Sox2 amplification occurs early in SCC pathogenesis, we investigated the oncogenic role of Sox2 using normal primary human lung basal progenitor cells. Although Sox2 is highly expressed in normal basal progenitors in a quiescent tracheal epithelium in vivo, we found that Sox2 expression decreases substantially during in vitro proliferation. When Sox2 expression is elevated in the proliferating basal cells in vitro to a level clinically observed in lung SCCs, Sox2 causes hyperplasia and promotes both squamous and Mucin16-positive glandular lineages at the expense of ciliated cell differentiation. Furthermore, our data suggest that the squamous and glandular-differentiating activity of Sox2 is differentially modulated by Receptor tyrosine kinase (RTK) and/or PI3-kinase signaling to promote squamous metaplasia of basal progenitor cells during SCC development.
78

The role of interleukin-12 in the pathogenesis of Sendai virus-induced airway disease /

Stone, Amy Elizabeth Seymour, January 2002 (has links)
Thesis (Ph. D.)--University of Florida, 2002. / Typescript. Vita. Includes bibliographical references (leaves 98-110).
79

Evaluation of Mesenchymal Stem Cell-Based Therapies for Inflammatory Lung Diseases

Ionescu, Lavinia Iuliana Unknown Date
No description available.
80

Recovery following pneumonectomy: patients initial 2 year experience

McLean, Jocelyn Margaret January 2003 (has links)
Little is known about the recovery of patients after pneumonectomy and the impact of the surgery on the lifestyle of young, employed, ex-smokers and their families. This study was conducted to address this knowledge deficit, and gather information that would help health professionals to be able to assist people facing pneumonectomy. A qualitative study using van Manens methodological approach to interpretive phenomenology was chosen, in order to capture a full and rich understanding and meaning of the phenomenon that patients live. The names, age, operation, histological cell type, stage of disease, and disease free status of potential participants were obtained from a Lung Cancer Surgical Database after obtaining ethical approval for the study. Nine participants (three females and six males) met the inclusion criteria and gave informed consent for the study. Data collection comprised of open-ended interviews that were audiotaped, then transcribed verbatim into hard data. Data interpretation was based on the selective reading approach of van Manen from which six thematic statements arose. These are living the discomforts of treatment and recovery, discovering new limitations on myself; functional and emotional, my reliance on support, my financial security is threatened, my survival is at threat, and I wish I had known more. The study found that each participant had a unique experience of recovery and consequently the degree of recovery attained varied between participants. They all had a very strong desire to survive lung cancer and considered the risks of major surgery and loosing a lung to be insignificant compared to the certainty of loosing their life if they did not undergo surgery. This study provided a glimpse of what it was like for a group of patients to live the experience of life after a pneumonectomy and it provides a basis from which nurses can explore further the experiences of patients who are subjected to lung cancer surgery.

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