• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 1036
  • 752
  • 180
  • 85
  • 68
  • 58
  • 49
  • 47
  • 32
  • 27
  • 16
  • 15
  • 14
  • 8
  • 7
  • Tagged with
  • 2765
  • 837
  • 362
  • 306
  • 296
  • 261
  • 235
  • 221
  • 212
  • 210
  • 183
  • 171
  • 166
  • 166
  • 163
  • 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.
461

Centrally located lung tumours treated with stereotactic body radiation therapy.

Karlsson, Kristin January 2006 (has links)
Background: This is a retrospective study of patients treated with stereotactic body radiation therapy (SBRT) with the stereotactic body frame for centrally located lung tumours. The purpose was to investigate the doses to the different structures of the tracheobronchial tree and to relate these doses to the incidence of atelectasis. The goal was to estimate a tolerance dose for the bronchi. Materials: The patient material consisted of 71 patient treated at the Karolinska University Hospital for a total of 102 tumours between November 1993 and March 2004. The patient group consisted of 36 men and 35 women with a mean age at the treatment of 67 years (range 34-87). The group was a mixture of patients with primary lung cancer and pulmonary metastases. Methods: After rereading and reactivating the dose plans for the patients in the treatment planning system (TPS) the different tracheobronchial structures (trachea, right mainstem bronchus, right superior bronchus, right intermedius bronchus, right medius bronchus, right inferior bronchus, left mainstem bronchus, left superior bronchus, left intermedius bronchus, left inferior bronchus) were outlined. The dose distribution in each structure was calculated and a dose-volume histogram (DVH) was created. Patients were allocated to four groups, i.e. patients with right sided tumours (22), left sided tumours (14), mediastinal tumours (23) and bilateral tumours (10). After that the maximum and mean doses to all structures were analysed. An oncologist reviewed the medical records for the patients and especially looked for atelectasis. The doses were related to the incidence of atelectasis. Results and Conclusions: For the patient group with right sided tumours it seems like the maximum doses to the bronchi are higher for the patients with atelectasis in comparison with patients without atelectasis. A better correlation between atelectasis and maximum doses rather than mean doses was observed for these patients. At this moment the results are too preliminary, so it is not possible to suggest a tolerance dose for the bronchi. What can be said is that the maximum doses to the bronchi for patients with right sided tumours without atelectasis are below 250 Gy3 expressed in biologically equivalent dose (BED) with α/β=3Gy, while at least one bronchi structure in the atelectasis patients received a maximum dose above 250 Gy3.
462

The expression and molecular functions of LRIG proteins in cancer and psoriasis / Uttryck och molekylära funktioner av LRIG proteiner i cancer och psoriasis

Karlsson, Terese January 2013 (has links)
The leucine-rich repeats and immunoglobulin-like domains (LRIG) family consists of three integral membrane proteins that are important in human cancer. LRIG1 is a negative regulator of growth factor signaling. Its expression is associated with longer survival in several cancer types, and the gene has been shown to function as a tumor suppressor. The roles of LRIG2 and LRIG3 are less well known. The aim of this thesis was to improve our understanding of the expression and function of the LRIG protein family in psoriasis and cancer. To investigate their expression in psoriasis, the mRNA levels and subcellular localization of the LRIG proteins were analyzed and compared between normal and psoriatic human skin. There were no differences in the LRIG mRNA levels between psoriatic and normal skin samples. However, the subcellular localization of all three LRIG proteins differed between psoriatic and normal skin. To study the physiological and molecular functions of Lrig2, we generated Lrig2E12-/- mice. These mice were viable and born at a Mendelian rate, but Lrig2E12-/- mice had an increased rate of spontaneous mortality and a transient reduction in growth rate compared to Lrig2 wild-type (wt) mice. In an orthotopic platelet-derived growth factor (PDGF)B-driven brain tumor mouse model, we studied the effect of Lrig2 on gliomagenesis. All Lrig2 wt mice developed tumors; 82% developed grade II/III tumors, and 18% developed grade IV tumors. Only 77% of the Lrig2E12-/- mice developed tumors, and they were all grade II/III tumors. Thus, Lrig2 increased the incidence and malignancy rates of PDGFB-driven gliomas. We then analyzed the effect of Lrig2 on Pdgf receptor (Pdgfr) signaling. Lrig2 had no effect on Pdgfr steady-state levels, the starvation-induced up-regulation of Pdgfrs, the phosphorylation of Pdgfrs, primary cilium formation or the PDGFBB-induced phosphorylation of Akt or Erk1/2. However, the kinetics of induction of the immediate-early genes Fos and Egr2 were altered, resulting in a more rapid induction in Lrig2E12-/- cells. We then analyzed the clinical and biological importance of LRIG1 in lung cancer. In a human lung cancer tissue micro-array (TMA), LRIG1 expression was found to be an independent positive prognostic factor for adenocarcinoma. To study the importance of Lrig1 regarding lung cancer development in vivo, we used an inducible EGFRL858R-driven mouse lung cancer model. The mice developed diffuse lung adenocarcinoma, and the tumor burden was greater in Lrig1-/- mice than in Lrig1+/+ mice (p = 0.025) at 60 days. The human lung cancer cell line H1975, with either normal or Tet-induced expression of LRIG1, was injected into the flanks of Balb/cA nude mice. Tumors formed by LRIG1-overexpressing cells were smaller than those formed by parental cells, further indicating that LRIG1 is important during lung tumor formation or growth. In vitro, LRIG1 suppressed the proliferation of H1975 cells and down-regulated the phosphorylation of MET and RET. To investigate the molecular functions of LRIG proteins further, we performed a yeast two-hybrid (YTH) screen using a peptide from the cytosolic tail of LRIG3 as bait. This screen identified LMO7 and LIMCH1 as prominent interaction partners for LRIG3. Proximity ligation assays showed that LMO7 interacted with all of the LRIG proteins at endogenous expression levels. LMO7 and LIMCH1 were expressed in all human tissues analyzed. Their expression was dramatically decreased in lung cancer compared to normal lung tissue. The expression of LMO7 was analyzed in a human lung cancer TMA. LMO7 was expressed in respiratory epithelial cells in normal lungs. However, LMO7 was only expressed in a quarter of the lung tumors. LMO7 expression was found to be an independent negative prognostic factor for lung cancer. In summary, we found that the LRIG proteins were redistributed in psoriatic skin. In a mouse glioma model, Lrig2 promoted oligodendroglioma genesis. LRIG1 was an independent positive prognostic factor in human lung cancer. Lrig1 ablation increased the tumor size in an EGFRL858R-driven lung cancer mouse model. LRIG1 expression decreased the tumor growth of human lung cancer cells in a xenograft mouse model. LMO7 interacted with all three LRIG proteins and was an independent negative prognostic factor in human lung cancer. These data demonstrate the importance of LRIG proteins in human disease.
463

Molecular Characterisation and Prognostic Biomarker Discovery in Human Non-Small Cell Lung Cancer

Edlund, Karolina January 2012 (has links)
Non-small cell lung cancer (NSCLC) constitutes a clinically, histologically, and genetically heterogeneous disease entity that represents a major cause of cancer-related death. Early-stage patients, who undergo surgery with curative intent, experience high recurrence rates and the effect of adjuvant treatment is modest. Prognostic biomarkers would be of particular relevance to guide intensified treatment depending on expected outcome and moreover often infer a biological role in tumourigenesis. This thesis presents a translational study approach to establish a well-characterised NSCLC frozen-tissue cohort and to obtain a profile of each specimen with regard to genome-wide copy number alterations, global gene expression levels and somatic mutations in selected cancer-related genes. Furthermore, the generation of a formalin-fixed, paraffin-embedded tissue microarray enabled validation of findings on the protein level using immunohistochemistry. The comprehensive molecular characterisation, combined with data on clinical parameters, enabled the analysis of biomarkers linked to disease outcome. In Paper I, single nucleotide polymorphism arrays were applied to assess copy number alterations in NSCLC and associations with overall survival in adenocarcinoma and squamous cell carcinoma were described. In Paper II, we evaluated expression levels of selected stromal proteins in NSCLC using immunohistochemistry and the adhesion molecule CD99 was identified as an outcome-related biomarker in two independent cohorts. Paper III presents a strategy for prognostic biomarker discovery based on gene expression profiling, meta-analysis, and validation of protein expression on tissue microarrays, and suggests the putative tumour suppressor CADM1 as a candidate biomarker. In Paper IV, we propose a prognostic role for tumour-infiltrating IGKC-expressing plasma cells in the local tumour microenvironment, indicating an involvement of the humoral immune response in anti-tumor activity. In Paper V, we combined next-generation deep sequencing with statistical analysis of the TP53 database to define novel parameters for database curation. In summary, this thesis exemplifies the benefits of a translational study approach, based on a comprehensive tumour characterisation, and describes molecular markers associated with clinical outcome in NSCLC.
464

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.
465

Considerations for Standard Chest Radiography: the Long Film-Focus Distance Technique

SAKUMA, SADAYUKI, ISHIGAKI, TAKEO, ITO, KENGO, IKEDA, MITSURU, HIROSE, MITSUHIKO 03 1900 (has links)
No description available.
466

Cisplatin, Etoposide, and Vincristine Combination Chemotherapy in the Treatment of Non-Small Cell Lung Cancer

SAITO, HIDEHIKO, SAKAI, SHUZO, NOMURA, FUMIO, SAKA, HIDEO, SAITO, HIROSHI, NAGURA, EIICHI, SHIMOKATA, KAORU, ICHIYAMA, SATOSHI, WATANABE, ATSUSHI 03 1900 (has links)
No description available.
467

Mechanisms of environmental tobacco smoke and benzo[a]pyrene induced cardiovascular injury and the protective role of resveratrol

Al-Dissi, Ahmad 21 March 2011
Despite extensive research, the mechanisms behind cardiovascular effects of subchronic environmental tobacco smoke (ETS) remain unclear, but may be related to ETS-induced inflammation and oxidative stress. Additionally, the protective role of resveratrol (RES), a natural antioxidant available in red grapes, is controversial. We hypothesized that the polycyclic aromatic hydrocarbon (PAH) component of ETS is responsible for causing adverse cardiovascular effects. We also hypothesized that the administration of RES is protective against the adverse cardiovascular effects of ETS. In order to address these hypotheses, male juvenile pigs (4-weeks old) were exposed to ETS or ambient air for 28 consecutive days (1 hr/day) and effects compared to 7 days of i.v. injection of the PAH, benzo-a-pyrene (BAP; 5 mg/kg daily). In another experiment, pigs were sham-exposed or ETS-exposed, with or without oral RES treatment (5mg/kg daily). In all experiments, endothelial and left ventricular function were assessed by flow mediated dilation (FMD), and echocardiography, respectively, while blood pressure was evaluated by oscillometry. At the termination of each experiment, serum nitrotyrosine, total nitrate/nitrite (NOx) and C-reactive protein (CRP) were measured as well as hepatic and pulmonary ethoxyresorufin-o-deethylase (EROD) activity to indicate cytochrome P450 1A1 (CYP1A1) expression. Finally, the correlation between pulmonary inflammation and adverse cardiovascular effects was investigated by measuring total and differential white blood cell (WBC) count as well as leukocyte elastase activity in bronchoalveolar lavage fluid at the termination of each experiment. ETS exposure, but not BAP treatment, resulted in a significant impairment of FMD (P<0.0001) and increased left ventricular end diastolic volume (P=0.0032). Cotreatment with RES failed to restore the ETS induced impairment of FMD (P>0.05). However, a trend pointing to an increase in ejection fraction (EF) was noted (P=0.072). ETS, BAP and RES treatments failed to have any effect on blood pressure (P>0.05). BAP injection caused a significant increase in serum nitrotyrosine (P=0.0146) and CRP (P=0.012), but not serum NOx levels (P>0.05). In contrast, ETS exposure resulted in a significant increase in CRP serum levels (P=0.0092), a trend pointing to increased serum nitrotyrosine (P=0.105), and no change in serum NOx levels (P>0.05). The increased nitrotyrosine and CRP with ETS exposure was not reversed by RES administration (P>0.05). ETS exposure increased EROD activity in the lung (P=0.0093), but not the liver (P=0.12). In contrast, BAP treatment had the opposite effect (lung EROD: P=0.621, liver EROD: P=0.01), while RES administration had no effect (P>0.05). ETS exposure (P=0.0139), but not BAP treatment (P=0.723), resulted in increased WBC count in BAL fluid which was not affected by RES administration (P>0.05). These results show that ETS exposure causes lung inflammation, systemic inflammation, oxidative stress-mediated inactivation of nitric oxide and impaired endothelial function. In contrast, BAP failed to alter endothelial function, downstream of the lung, despite systemic inflammation and increased oxidative stress. Furthermore, RES failed to restore endothelial function, or decrease systemic inflammation and oxidative stress. Taken together, these results suggest either that pulmonary inflammatory responses or pulmonary increases in CYP1A1 activity may be more important links to endothelial dysfunction than systemic inflammation and nitric oxide bioactivity. The beneficial effects of RES by itself are manifested only at the cardiac level by improving the ejection fraction, but the work in this thesis failed to detect any ability of RES to ameliorate ETS cardiovascular effects.
468

Molecular mechanisms of neutrophil and monocyte recruitment in acute lung inflammation

Janardhan, Kyathanahalli Sampath Iyengar 05 July 2006
Neutrophils are implicated in many inflammatory lung disorders. However, the mechanisms regulating neutrophil migration in acute lung inflammation are incompletely understood. Although, integrin β2 mediates neutrophil migration in lungs in response to many stimuli such as E. coli, integrin involved in <i>S. pneumoniae</i> induced neutrophil migration is not known. Therefore, the role of integrin αvβ3 in neutrophil recruitment was tested. First, it was found that the number of neutrophils expressing the integrin subunits αv and β3 is reduced or remains in lung inflammation induced by E. coli or <i>S. pneumoniae</i>, respectively. Next, the role of integrin αvβ3 using β3 knockout mice (β3-/-) and function blocking antibodies was addressed. Neutrophil recruitment did not vary between wild type and β3-/- mice. Although β3 antibodies reduced neutrophil recruitment, similar effect was observed with isotype antibodies. Therefore, one can conclude that integrin αvβ3 is not critical for neutrophil recruitment in <i>S. pneumoniae</i> induced pneumonia. <p>Apart from integrins, TLR4 also regulate neutrophil migration. Because, the pattern of TLR4 expression at various times of lung inflammation is not known, TLR4 expression during different phases of lung inflammation in a rat model of LPS-induced inflammation was studied. TLR4 expression in the septum increased and decreased at 6h and 12-36h of inflammation, respectively. Since these correlate with the time of increase and decline of neutrophil recruitment, the findings support previously observed requirement for TLR4 in neutrophil recruitment. <p>Neutrophils recruited into the lungs regulate the inflammatory process by controlling subsequent monocyte/macrophage recruitment. The mechanisms involved and the pattern of monocyte/macrophage recruitment in lungs are not completely understood. Therefore, the possible involvement of monocyte chemoattractant protein (MCP)-1, which is a premier chemokine in monocyte/macrophage migration and produced by neutrophils and other cells was tested. This was addressed by quantification of monocytes/macrophages at various times and using neutrophil depletion experiments in LPS-induced lung inflammation in rats. It was found that monocytes/macrophages migrate very early and before neutrophils in addition to their migration in the late phase of acute lung inflammation. Neutrophil depletion abrogated both early as well as the late monocyte/macrophage recruitment without altering the expression of MCP-1. Therefore, possibly other chemokines and not MCP-1 are involved in neutrophil dependent monocyte/macrophage recruitment. <p>To conclude, the experiments further the understanding on acute lung inflammation by ruling-out the involvement of integrin αvβ3 and MCP-1 in β2-independent neutrophil migration and neutrophil dependent monocyte/macrophage recruitment, respectively. Further studies are essential to find the integrins and chemokines operating in the above situations. Equally important will be to understand the functional significance of early recruited monocytes/macrophages in the lung.
469

The Development of a Phenotype for Lung Disease Severity in Cystic Fibrosis and its Application in the CF Gene Modifier Study

Taylor, Chelsea Maria 07 January 2013 (has links)
Genetic studies of lung disease in Cystic Fibrosis are faced with the challenge of identifying a severity measure that accounts for chronic disease progression and mortality attrition. Further, combining analyses across studies requires common phenotypes that are robust to study design and patient ascertainment. This thesis uses data from the North American Cystic Fibrosis Modifier Consortium (Canadian Consortium for CF Genetic Studies (CGS), Johns Hopkins University Twins and Siblings Study (TSS), and University of North Carolina/Case Western Reserve University Gene Modifier Study (GMS)), to calculate two novel phenotypes using age-specific CF percentile values of FEV1 (Forced Expiratory Volume in 1 second), with adjustment for CF age-specific mortality. The normalized residual, mortality adjusted (NoRMA) was designed for population based samples, while KNoRMA, using Kulich percentiles, is robust to sample ascertainment; both account for the effects of age-related disease progression and mortality attrition. NoRMA was computed for 2122 patients representing the Canadian CF population. KNoRMA was computed for these 2122 patients and also 1137 extreme phenotype patients in the GMS study and 1323 patients from multiple CF sib families in the TSS study. Phenotype was distributed in all three samples in a manner consistent with ascertainment differences, reflecting the lung disease severity of each individual in the underlying population. The new phenotype was highly correlated with the previously recommended mixed model phenotype1; 2, but computationally much easier and suited to studies with limited follow up time. As an example of its use, KNoRMA was used to test the association between locus variants in a previously published candidate gene, Transforming Growth Factor β1(TGFβ1), and lung function in CF, in an attempt to provide insight into discrepant results in the literature. A disease progression and mortality adjusted phenotype reduces the need for stratification or additional covariates, increasing statistical power and avoiding possible interpolation distortions.
470

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.

Page generated in 0.0294 seconds