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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.
471

Exploring the Suitability of a Specifici Glucocorticoid Receptor Antagonist as a Tool in the Study of the Regulation of Rat Lung Alveolarization by Glucocorticoids

Lopez, Ana Sofia 10 January 2011 (has links)
Background: Intracellular glucocorticoid receptors (GRs) mediate the regulation of lung development, including alveolarization, by glucocorticoids (GCs). One potential approach to determining the role of GC-GR signalling in alveolar formation would be by pharmacologic blockade. Hypothesis: CP472555, a novel GR antagonist with negligible anti-PR activity, is a suitable tool for the study of GC-GR regulation of rat alveolarization. Design/Methods: CP472555 doses needed to block GR were estimated in vitro in fetal rat lung primary cultures. Postnatally, a variety of doses were administered intraperitoneally over a range of days. Results: During postnatal days (PN)0-PN10, when GC levels are low, CP472555 induced changes consistent with GR agonist activity. While GC levels increase after PN11, animals exposed to CP472555 from PN11-PN21 exhibit changes consistent with anti-GR antagonist activity. Conclusion: CP472555 causes a degree of GR blockade sufficient to permit further pharmacological investigation of the role of endogenous GC-GR signalling at the end of alveolarization.
472

Role of Reactive Oxygen Species in Normal Postnatal Lung Growth

Jamal, Mobin 20 November 2012 (has links)
Rationale/ Hypothesis: Reactive oxygen species, including lipid hydroperoxides, play a critical role as second messengers in many physiological processes in the body. Heightened reactive oxygen species production at the time of birth imposes an oxidative stress upon the lung, which may trigger postnatal alveologenesis and physiological lung cell apoptosis in the neonatal rat. Methods: Neonatal rats were subcutaneously injected daily with vehicle (corn oil) or diphenyl-phenyl diamine for the first 6 days of life to study alveologenesis and physiological lung cell apoptosis. Add-back experiments were conducted with a prototypic lipid hydroperoxide, t-butyl hydroperoxide. Main Results: Treatment with diphenyl-phenyl diamine resulted in parenchymal thickening, reduced numbers of secondary crests and enlarged air spaces, all consistent with the inhibition of alveologenesis and reduced physiological lung cell apoptosis. Conclusion: Following an oxidative stress at birth, lipid hydroperoxide formation triggers postnatal alveologenesis and physiological lung cell apoptosis in the neonatal rat.
473

Assessing the use of the steep ramp test in chronic obstructive pulmonary disease

Chura, Robyn Lorraine 21 September 2009
The purpose of this study was to compare power output and ventilatory measurements between the steep ramp test (SR) and both the 30-second Wingate anaerobic (WAT) and standard cardiopulmonary exercise tests (CPET) in chronic obstructive pulmonary disease (COPD). 11 patients (7 males and 4 females) underwent spirometry, a CPET, WAT and SR test. Repeated measures ANOVA was used to compare the differences between the peak work rate of the CPET (CPET<sub>peak</sub>), SR (SR<sub>peak</sub>), and the average power of the WAT (W<sub>avg</sub>). The W<sub>avg</sub> was higher than the SR<sub>peak</sub>, which was higher than the CPET (231.2 ± 113.4, 156.8 ± 67.9, 65.9 ± 35.9, p>0.05 respectively). There were no differences found between the tests at end-exercise for inspiratory reserve volume (IRV), ventilation (V<sub>E</sub>), and end-expiratory lung volume (EELV). Tidal volume (V<sub>T</sub>) was also compared between the tests as a percentage of the inspiratory capacity (IC) remaining at end-exercise and no differences were found. The similarity between the ventilatory measures indicates a similar level of constraint, despite the large difference in work rates achieved, in all 3 tests. This shows that a standard CPET underestimates leg power in COPD patients, and the WAT and SR may be better indicators of leg muscle power and anaerobic type exercise.
474

Recruitment and function of pulmonary intravascular macrophages in rats

Gill, Sukhjit Singh 12 September 2005
<p>with biliary cirrhosis are highly susceptible to acute pulmonary dysfunction and suffer from hepato-pulmonary syndrome. The mechanisms of this enhanced susceptibility remain unknown. It is well established that pulmonary intravascular macrophages (PIMs) are present in cattle, horses, goat and sheep and increase susceptibility for lung inflammation. Species such as rat and mouse also recruit PIMs especially in a bile duct ligation model of biliary cirrhosis. The contributions of recruited PIMs to lung inflammation associated with liver dysfunction remain unknown. Therefore, I characterized a bile duct ligation (BDL) model in rats to study role of recruited PIMs in lung inflammation. First, Sprague Dawley rats were subjected to BDL (N=6) or sham surgeries (N=3) and were euthanized at 4 weeks post-surgery. Five rats were used as the controls. Lung tissues were collected and processed for histology, immunohistology, immuno-electron microscopy, enzyme-linked immunosorbant assay (ELISA) and reverse transcriptase-polymerase chain reaction (RT-PCR). Light microscopy demonstrated normal lung morphology in sham-operated and control rats but showed septal recruitment of mononuclear cells, which were positive for anti-rat monocytes/macrophage antibody ED-1, in BDL rats (p=0.002). Immuno-electron microscopy confirmed localization of ED-1 in PIMs. BDL rats showed increased lung expression of monocyte chemoattractant protein-1 (MCP-1) protein and mRNA compared to the controls (p=0.017) but not of IL-1â, TNF-á, TGF-â and IL-10. Then, I treated BDL rats (N=5) with gadolinium chloride (GC; 10 mg/Kg body weight intravenous) and found reduced numbers of PIMs (p=0.061) at 48 hours post-treatment along with increased expression of TGF-â and IL-10.</p><p>I challenged control rats (N=5) and BDL rats (N=6) with Escherichia coli lipopolysaccharide (E. coli LPS; 0.1 mg/Kg body weight intravenous). All the BDL rats died within 3 hours of LPS challenge (100% mortality) while the normal LPS-treated rats were euthanized at 6 hours post-treatment. Histology and ED-1 staining showed dramatic increase in the number of septal monocytes/macrophages in BDL+LPS rats compared to normal LPS-treated rats (p=0.000). Staining of lung sections with an LPS antibody localized the LPS in lungs. RT-PCR analyses showed no differences in IL-1â transcript levels between LPS challenged BDL rats and LPS challenged control rats (p=0.746) but ELISA showed increase in IL-1â concentration in LPS challenged BDL rats compared to LPS challenged control rats (p=0.000). TNF-á mRNA (p=0.062) and protein (p=0.000) was increased in BDL+LPS rats compared to the control+LPS rats. Immuno-electron microscopy showed IL-1â and TNF-á in PIMs. BDL rats challenged with LPS showed increased expression of IL-10 mRNA and protein (p=0.000 & 0.002 respectively) in lungs compared to LPS challenged control rats. TGF-â mRNA did not change (p=0.128) but lower protein concentrations (p=0.000) were observed in LPS-treated control rats compared to BDL+LPS. </p><p> To further address the role of PIMs, I treated rats with GC at 6 hours or 48 hours (N=5 each) before LPS challenge. The mortality in the 6 hour group was 20% while all the rats in 48 hour group survived till 6 hours. Histology and ED-1 staining showed decrease in the number of intravascular cells in these groups compared to LPS treated BDL rats (p=0.039 for 6 hour group; p= 0.002 for 48 hour group). There were no differences in IL-1â mRNA in both 6 hour and 48 hour groups compared to the LPS challenged BDL rats (p=0.712 & 0.509 respectively). ELISA showed no decrease in IL-1â concentration in 6 hour GC-treated group but a decrease was noticed at 48 hours compared to LPS challenged BDL rats (p=0.455 & 0.008 respectively). TNF-á mRNA levels were not different between LPS-challenged GC-treated BDL rats and LPS-challenged BDL rats (p=0.499 & 0.297 for 6 hour & 48 hour GC groups respectively). But TNF-á concentration in 48 hour GC group (p=0.001) but not in 6 hour GC group (p=0.572) was lower in comparison to BDL+LPS group. IL-10 mRNA was decreased in both 6 hour and 48 hour GC groups (p=0.038 & 0.000 respectively) compared to LPS challenged BDL rats. ELISA showed decrease in IL-10 concentration in 48 hour GC group (p=0.030) but not in 6 hour GC group (p=0.420). TGF-â mRNA expression was decreased in 48 hour GC group (p=0.000) but not in 6 hour GC group (p=0.182). But GC treatment did not affect TGF-â concentrations. </p><p>The data from these experiments characterize a BDL model to study PIM biology, show PIMs pro-inflammatory potential and their possible role as a therapeutic target in lung inflammation.</p>
475

High-performance Dual-energy Imaging with a Flat-panel Detector

Shkumat, Nicholas Andrew 25 July 2008 (has links)
Mounting evidence suggests that the superposition of anatomical clutter in x-ray chest radiography poses a major impediment to the detectability of subtle lung nodules. Through decomposition of projections acquired using different x-ray energy spectra, dual-energy (DE) imaging offers to dramatically improve lung nodule conspicuity. The development of a high-performance DE chest imaging system is reported, with design and implementation guided by fundamental imaging performance metrics. Analytical and experimental studies of imaging performance guided the optimization of key acquisition technique parameters, including x-ray filtration, allocation of dose between low- and high-energy projections, and peak-kilovoltage selection. To minimize anatomical misregistration between images, a cardiac gating system was designed and implemented to direct x-ray exposures to within the quiescent period of the heart cycle. The instrumentation and optimal imaging techniques have been incorporated in a DE imaging prototype system now deployed in a clinical study to evaluate the diagnostic performance of DE imaging.
476

Environmental Risk Factors for Lung Cancer Mortality in the Cancer Prevention Study-II

Turner, Michelle C 10 January 2012 (has links)
This thesis examined associations between ecological indicators of residential radon and fine particulate matter air pollution (PM2.5) and lung cancer mortality using data from the American Cancer Society Cancer Prevention Study-II (CPS-II) prospective cohort. Nearly 1.2 million CPS-II participants were recruited in 1982. Mean county-level residential radon concentrations were linked to study participants according to ZIP code information at enrollment (mean (SD) = 53.5 (38.0) Bq/m3). Cox proportional hazards regression models were used to obtain adjusted hazard ratios (HRs) and 95% confidence intervals (CI) for lung cancer mortality associated with radon. After necessary exclusions, a total of 811,961 participants in 2,754 counties were retained for analysis. A significant positive linear trend was observed between categories of radon concentrations and lung cancer mortality (p = 0.02). A 15% (95% CI 1 - 31%) increase in the risk of lung cancer mortality was observed per each 100 Bq/m3 radon. Radon was also positively associated with chronic obstructive pulmonary disease mortality (HR per each 100 Bq/m3 = 1.13, 95% CI 1.05 - 1.21). No clear associations were observed between radon and non-respiratory mortality. In lifelong never smokers (n = 188,699), each 10 µg/m3 increase in mean metropolitan statistical area PM2.5 concentrations was associated with a 15-27% increase in the risk of lung cancer death which strengthened among individuals with a history of asthma or any prevalent chronic lung disease at enrollment (p for interaction < 0.05). There was no association between PM2.5 and mortality from non-malignant respiratory disease. In conclusion, this thesis observed significant positive associations between ecological indicators of residential radon and PM2.5 concentrations and lung cancer mortality. These findings further support efforts to reduce radon concentrations in homes to the lowest possible level and strengthens the evidence that ambient concentrations of PM2.5 measured in recent decades are associated with small but measurable increases in lung cancer mortality. Further research is needed to better understand possible complex inter-relationships between environmental risk factors, chronic lung disease, and lung cancer.
477

Anàlisi de polimorfismes d’una sola base (SNPs) com a factors predictius de recaiguda en pacients amb càncer de pulmó de cèl•lula no petita quirúrgic

Campayo Guillaumes, Marc 22 December 2011 (has links)
1) Hipòtesi El càncer de pulmó és la neoplàsia més freqüent en el moment actual i és la primera causa de mort per càncer en el món. Aproximadament el 85 % dels pacients presenten CPCNP. Inclús els casos identificats en estadis precoços i en què es pot realitzar un tractament quirúrgic curatiu, tenen un risc de recaiguda global del 60%. A pesar dels avenços en el tractament de la malaltia realitzats durant els darrers anys, la supervivència global continua essent molt baixa, al voltant del 15 % als 5 anys. És per aquest motiu que es fa necessària la troballa de biomarcadors que puguin predir el risc de recaiguda, una vegada realitzada la resecció quirúrgica. Aquests biomarcadors ens permetrien estratificar els pacients pel seu risc i individualitzar el seguiment i el tractament de la malaltia, especialment en els pacients en estadi I que no reben cap tractament adjuvant. La majoria de pacients amb CPNCP són fumadors i durant els últims anys s’ha observat que variants polimòrfiques d’enzims relacionats amb la metabolització de carcinògens del tabac, en gens de reparació del DNA o en gens relacionats amb l’expulsió de carcinògens de la cèl•lula s’han associat a un risc augmentat de càncer de pulmó. No obstant, l’impacte d’aquests SNPs en la recaiguda del CPCNP no ha estat establert. Si tenim en compte que els SNPs són característiques innates dels individus, podríem pensar que la seva presència podria tenir un efecte també en la recaiguda de pacients fumadors que han desenvolupat un càncer de pulmó, ja que les diferencies genotípiques es podrien traduir en diferències en el procés de malignització mediat pel tabac. Aquests SNPs doncs podrien seleccionar-nos individus que han tingut un risc incrementat de càncer de pulmó i que, una vegada realitzat un tractament local quirúrgic, podrien tenir un risc augmentat de recidivar. Per altre banda recentment els miRNAs han esdevingut com a elements claus en el procés de carcinogènesi. Els miRNAs són molècules que controlen la diferenciació i el creixement cel•lular i en diferents tipus tumorals s’associen a l’evolució de la malaltia. Polimorfismes en gens relacionats amb miRNAs implicats en càncer o en els propis miRNAs poden jugar un paper en la progressió tumoral. Més concretament, polimorfismes en gens de la via de processament dels miRNAs o en la seqüència del pri-miRNA o pre-miRNA poden afectar als nivells finals de determinats miRNAs. A més, polimorfismes en les seqüències d’anclatge de miRNAs poden reprimir la inhibició dels gens diana per aquests i per tant, afectar la seva funció. En definitiva, polimorfismes relacionats amb els miRNAs podrien modificar el risc de recaiguda després de la cirurgia en pacients amb CPCNP. Basant-nos en aquestes hipòtesis ens plantegem els següents objectius: 2) Objectiu general Trobar biomarcadors de recaiguda i supervivència global en pacients quirúrgics de CPCNP basant-nos en l’estudi de les variants polimòrfiques del DNA. 3) Objectius específics 1. Analitzar, en una sèrie retrospectiva de pacients amb CPCNP quirúrgics, polimorfismes en gens relacionats amb el metabolisme del tabac (fase I i fase II), gens de reparació del DNA i en el gen MDR1/ABCB1 en pacients amb hàbit tabàquic. 2. Analitzar polimorfismes presents en regions del DNA codificants per miRNAs relacionats amb proliferació, apoptosi, angiogènesi i cicle cel•lular en una sèrie retrospectiva de pacients amb CPCNP quirúrgics. 3. Analitzar polimorfismes presents en els gens que intervenen en el procés de maduració dels miRNAs en una sèrie retrospectiva de pacients amb CPCNP quirúrgics. 4. Analitzar polimorfismes localitzats al lloc d’anclatge del miRNA al mRNA en una sèrie retrospectiva de pacients amb CPCNP quirúrgics. 5. Establir si existeix relació entre els diferents genotips i el temps a la recaiguda o la supervivència global.
478

Bioactive Poly(ethylene glycol)-based Hydrogels for Characterization of Matrix Influences on a Lung Cancer Metastasis Model

Gill, Bj 16 September 2013 (has links)
Pathological changes to tumor extracellular matrix (ECM) composition, mechanics, and architecture promote cancer progression and metastasis. Exploration of tumor-ECM interactions using in vitro matrix-mimetic culture systems has largely been restricted to naturally-derived matrix materials that permit limited experimental control. Such study of a novel lung adenocarcinoma model in Matrigel™ (MG) has suggested key matrix cues that mediate epithelial-mesenchymal transition (EMT) and metastasis. In this thesis work, synthetic hydrogel scaffolds based on poly(ethylene glycol) (PEG) featuring high experimental control and modular bioactivity were used to study matrix influences on the EMT-prone model line 344SQ. Encapsulation of 344SQ cells in PEG hydrogels modified for cell adhesivity and cell-mediated enzymatic degradability induced formation of lumenized, polarized spheres mimicking the epithelial phenotype observed in three-dimensional MG. Tuning matrix stiffness, adhesive ligand concentration, and ligand spatial presentation altered epithelial morphogenesis. Exploration of the EMT phenotype of PEG-encapsulated 344SQ cells revealed TGFβ-initiated changes in morphology, polarity, expression levels of EMT marker genes and their epigenetic controller, and the organization of cell-secreted ECM. Notably, a potent role for adhesive ligand was illuminated as matrices with low PEG-RGDS concentration even in the absence of TGFβ induced formation of spheres with a post-EMT phenotype by several of these measures. A matrix-invasive phenotype was also revealed by altering matrix structural parameters and tuned with incorporation of an alternative protease-cleavable sequence. Finally, the influence of cell-cell contacts was explored by covalent incorporation of cadherin proteins into the matrix. Matrix-tethered E- and -N-cadherin affected 344SQ sphere development in otherwise non-cell-adhesive matrices and modulated polarity and the degree of TGFβ response. Further, in 344SQ with a knockdown of the essential polarity-determining protein Scribble, matrix-tethered cadherin influenced the formation of a phenotype with partially normalized epithelial polarity with corresponding differences in membrane localization of cell-expressed E-cadherin. Overall, this thesis demonstrates the utility of the more experimentally controllable PEG system in studying ECM influences on cancer progression with findings providing greater insight into stromal biomechanical, biochemical, and cell-cell factors that mediate lung adenocarcinoma epithelial morphogenesis and EMT. These contributions help advance the state of the field towards a goal of developing new metastasis-targeting cancer therapeutics.
479

Upplevelser av att leva med lungcancer : En litteraturbaserad studie / Experiences of living with lung cancer : A literature study

Bergström, Evelyn, Bega, Arijana January 2011 (has links)
Bakgrund: Lungcancer är en sjukdom som har en dålig prognos och där ett stort antal människor insjuknar årligen. Det är en sjukdom som leder till många och svåra symtom vilket skapar stort lidande. Syfte: Syftet med denna studie var att beskriva patienters upplevelser av att leva med lungcancer i det dagliga livet. Metod: En litteraturbaserad studie genomfördes med en kvalitativ ansats. Tolv vetenskapliga artiklar granskades och analyserades enligt en modell för en litteraturbaserad studie. Resultat: Ur resultatet identifierades sex kategorier: leva med osäkerhet, stigma och skuld, upplevelser av sjukdomsrelaterade symtom, en förändrad självkänsla, att få stöd och bli bekräftad samt pendla mellan hopp och förtvivlan. Diskussion: Det fanns ett behov hos patienterna av att leva så självständig som möjligt, där det sociala stödet och stödet från vårdpersonal var avgörande för att de skulle klara av det. Stöd överhuvudtaget var viktigt för att patienterna skulle kunna hantera de flesta situationer. Genom att sjuksköterskan får kunskap om patienters upplevelser av lungcancer kan patienters lidande lindras med hjälp av stöd från sjuksköterskan. / Background: Lung cancer is a disease with poor prognosis, with many people that falls ill each year. It is a disease which leads to numerous and severe symptoms that create much suffering. Aim: The aim of this study was to describe patients' experiences of living with lung cancer in daily life. Methods: A literature study was conducted with a qualitative approach. Twelve scientific articles were reviewed and analyzed according to a model for a literature study. Results: Six categories were identified: live with uncertainty, stigma and guilt, experience of disease-related symptoms, a changed self-esteem, to get support and be confirmed and thrown between hope and despair. Discussion: There was a need for patients to live as independent as possible, social support and the support from health professionals was crucial for them to cope with it. Support overall was important for patients to be able to handle most situations. By acquiring knowledge about patients' with lung cancers experiences the nurse can be a better support for the patient in order to alleviate patients suffering.
480

Genetic heterogeneity of EGFR and KRAS mutations in primary tumor tissue from non-small cell lung cancer patients

Mattsson, Johanna January 2011 (has links)
Activated epidermal growth factor receptor (EGFR) and Kirsten rat sarcoma viral oncogene homolog (KRAS) mutations characterize molecular subgroups of non-small cell lung cancer (NSCLC) and have a strong predictive value for response to EGFR inhibitor therapy. Recently, EGFR mutation testing was included in the diagnostic algorithm of NSCLC. However, there is a controversy about the clonal stability of the mutation during the progression of the disease. The aim of this study was to analyze NSCLC tumor tissue for the presence of both EGFR and KRAS mutations in morphologically different parts of the primary tumor. Formaldehyd fixed and paraffin embedded lung cancer specimens from primary resected NSCLC patients were selected; five cases harboring EGFR and five with KRAS mutations. From each tumor, three morphologically different tumor sites were manually micro-dissected and analyzed for the presence of EGFR and KRAS mutations. Additionally, normal lung tissue at a distance from the primary tumor as well as in close vicinity was tested.The EGFR and KRAS status were consistent in the three different areas of the primary tumors of all ten cases. EGFR as well as KRAS mutations were as well detectable in close and in some distant normal lung parenchyma in 7 of 10 analyzed patient samples. In conclusion, we found consistent KRAS and EGFR mutation status in primary NSCLC tumors. This finding is of importance for clinical practice, because it indicates that any part of the tumor, independent of intratumoral histological pattern, is representative for EGFR and KRAS mutation testing.

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