• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 138
  • 136
  • 72
  • 41
  • 11
  • 9
  • 9
  • 6
  • 4
  • 4
  • 3
  • 3
  • 2
  • 1
  • 1
  • Tagged with
  • 496
  • 147
  • 114
  • 100
  • 98
  • 98
  • 88
  • 86
  • 83
  • 69
  • 66
  • 60
  • 52
  • 46
  • 45
  • 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.
41

Development of microfluidics-based neutrophil migration analysis systems for research and clinical applications

Wu, Jiandong January 2016 (has links)
Immune cell migration and chemotaxis plays a key role in immune response. Further research to study the mechanisms of immune cell migration and to develop clinical applications requires advanced experimental tools. Microfluidic devices can precisely apply chemical gradient signals to cells, which is advantageous in quantifying cell migratory response. However, most existing microfluidic systems are impractical to use without specialized facilities and research skills, which hinders their broad use in biological and medical research communities. In this thesis, we integrated several new developments in microfluidic gradient generating devices, compact imaging systems, on-chip cell isolation, cell patterning, and rapid data analysis, to provide an easy-to-use and practical solution for immune cell migration and chemotaxis experiments. Using these systems, we quantitatively studied neutrophil migration for both research and clinical applications. First, we developed a compact USB microscope-based Microfluidic Chemotaxis Analysis System (UMCAS), which integrates microfluidic devices, live cell imaging, environmental control, and data analysis to provide an inexpensive and compact solution for rapid microfluidic cell migration and chemotaxis experiments with real-time result reporting. To eliminate the lengthy cell preparation from large amounts of blood, we developed a simple all-on-chip method for magnetic isolation of untouched neutrophils directly from small volumes of blood, followed by chemotaxis testing on the same microfluidic device. Using these systems, we studied neutrophil migration in gradients of different chemoattractants, such as interleukin-8 (IL-8), N-formyl-methionyl-leucyl-phenylalanine (fMLP), and clinical sputum samples from Chronic Obstructive Pulmonary Disease (COPD) patients. Previous studies have shown that COPD is correlated with neutrophil infiltration into the airways through chemotactic migration. The thesis work is the first application of the microfluidic platform to quantitatively characterizing neutrophil chemotaxis to sputum samples from COPD patients. Our results show increased neutrophil chemotaxis to COPD sputum compared to control sputum from healthy individuals. The level of COPD sputum induced neutrophil chemotaxis was correlated with the patient’s spirometry data. Collectively, the research in this thesis provides novel microfluidic systems for neutrophil migration and chemotaxis analysis in both basic research and clinical applications. The developed microfluidic systems will find broad use in cell migration related applications. / May 2016
42

Understanding the reasons for non-participation in self-management interventions amongst patients with chronic conditions : addressing and increasing opportunities for patients with advanced chronic obstructive pulmonary disease to access self-management

Sohanpal, Ratna January 2015 (has links)
Background: In chronic obstructive pulmonary disease (COPD), understanding the problem of poor patient participation in evidence-based self-management (SM) and pulmonary rehabilitation (PR) programmes (together referred to as SM support programmes) is critical. This thesis aimed to improve understanding of poor patient participation and retention in these programmes; how participation might be improved; and how might patients be better supported with their SM. Methods: Using the Medical Research Council guidance on complex interventions this thesis (1) quantified the 'actual' patient participation and completion rates; (2) explained, using theory, the factors that influenced participation in studies of SM support including the programmes among chronic disease and COPD patients; and (3) explored patient and expert stakeholders' perspectives on the reasons for non-participation in SM support programmes, how participation might be improved, how might patients be supported with their SM. Results: (1) Among 56 studies, high study participation rates and completion rates were seen however, the incomplete reporting of participant flow confused the problem of participation. (2) Among 31 studies, participation among patients with chronic disease including COPD was shown to be influenced by their 'attitude' and 'perceived social influence/subjective norms'; 'illness' and 'intervention perceptions'. (3) From 38 interviewees, besides patients' beliefs, non-participation was also influenced by resignation and denial of the illness; health systems; and programme organisational factors. Professionals building relationships and supporting patients with their SM alongside programme organisational improvements might encourage patient participation in SM and the programmes. Conclusions Patient participation is a complex behaviour, besides socio-behavioural factors, participation behaviour can by influenced by a mix of several health system and programme organisational factors. Changing the behaviour of health professionals and indeed the wider health system, towards normalising a patient partnership approach, with implementation of SM support in routine care might help more patients to consider participation in their care and improve patient participation in COPD SM support programmes.
43

Effects of xanthine oxidase inhibitors in pulmonary hypertension associated with chronic lung disease

Liu Shiu Cheong, Patrick January 2019 (has links)
Chronic lung diseases are often complicated with pulmonary hypertension (PH). This can lead to disability and poor prognosis. Oxidative stress has been implicated in the development of PH and right ventricular hypertrophy (RVH).A possible new way to treat lung disease related pulmonary hypertension is allopurinol (a xanthine oxidase inhibitor) which decreases both uric acid and oxidative stress. We hypothesised that allopurinol could regress RVH in patients with pulmonary hypertension associated with chronic lung disease (PH-CLD).In a double-blind, randomised controlled clinical trial, 72 patients with PH-CLD (93% diagnosed with chronic obstructive pulmonary disease and 17% with interstitial lung disease) were randomised to receive either allopurinol 300 mg twice daily or placebo for twelve months. The primary outcome was the mean change in right ventricular mass (RVM) as assessed by cardiac magnetic resonance imaging (CMRI) at twelve months. The secondary outcomes were the change in other cardiac parameters measured by CMRI, St George's Respiratory Questionnaire, Short Form 36, spirometry and six-minute walk test (6MWT).The mean age was 71 years, the mean FEV1 was 60% with mean resting SaO2 of 96%. After 12 months, there was no significant change in RVM. There were also no significant changes in other cardiac parameters measured on CMRI, quality of life questionnaires, spirometry and 6MWT. Post-hoc subgroup analysis showed that allopurinol reduced RVM (allopurinol -6.16 g vs placebo 0.75 g, p = 0.02) in COPD patients with more severe airflow limitation. Patients with higher NT-proBNP (> 489 pg/ml) had a greater improvement in left ventricular ejection fraction with allopurinol 5.12 vs placebo -1.62, p = 0.02.In summary, allopurinol had no overall impact but reduced RV mass in COPD patients with more severe airflow limitation. Further studies are warranted to assess the longer term impact of allopurinol in more severe COPD.
44

Effects of COPD and its treatment on cardiovascular structure and function assessed through advanced imaging techniques

Stone, Ian January 2016 (has links)
Significant cardiovascular morbidity and mortality exists in chronic obstructive pulmonary disease independent of traditional risk factors. A number of different hypotheses exist to explain this association including the contribution arterial stiffness and lung hyperinflation. Non-invasive cardiovascular imaging and assessment are ideal methods through which this relationship can be further studied although a number of the techniques have yet to be validated in COPD. In this thesis we aimed to achieve a number of goals. First, we aimed to assess the reproducibility and level of agreement between different measures of arterial stiffness in stable hyperinflated COPD. Second, we hoped to establish the utility of 3 different measurement techniques for measuring intrinsic cardiac function in stable hyperinflated COPD. Third, in a case-control study we compared surrogates of cardiovascular risk in hyperinflated COPD patients and a group matched for cardiovascular risk with normal lung function. Finally, we sought to understand the impact of pharmacologically reducing lung hyperinflation on cardiovascular structure, function and arterial stiffness. We have firstly demonstrated that non-invasive measures of arterial stiffness are reproducible in stable hyperinflated COPD. Secondly, we have established the level of agreement and reproducibility of three different CMR techniques for measuring intrinsic myocardial function which will provide important information for the powering of future CMR studies in COPD. Thirdly, we have shown that surrogates for cardiovascular outcomes are adversely affected in COPD compared to a group matched for global cardiovascular risk, suggesting that current scoring systems may be suboptimal in risk prediction in COPD. Finally, we have demonstrated that pharmacological lung deflation has consistent and physiologically plausible beneficial effects on cardiac structure, function and the pulmonary vasculature. Whether intrinsic myocardial function can be modulated through prolonged periods of lung deflation is as yet unverified and should be the focus of future clinical trials.
45

Exhaled breath analysis for diagnosis and phenotyping in obstructive lung diseases

Ibrahim, Baharudin January 2011 (has links)
Introduction: Asthma and chronic obstructive pulmonary disease (COPD) are heterogeneous diseases with a wide range of clinical manifestations not adequately described within the current diagnostic criteria. Exhaled breath analysis may provide a novel method for diagnosing and phenotyping these diseases. Our aim was to ascertain patterns of breath volatile organic compounds (VOCs) and nuclear magnetic resonance (NMR) spectral regions identifying diseased patients and subgroups determined by treatment requirement, asthma control, exacerbation frequency and inflammatory phenotypes. The validity and reproducibility of the methodology and the outcome were also investigated. Methods: Three separate clinical studies (two involving exhaled gas and one involving breath condensate) were conducted, as well as validation studies. In exhaled gas analysis, the adaptive breath sampler developed by Basanta et al was modified; efficiency of air supply and air filter and the reproducibility and stability of VOCs in storage were determined by comparing breath chromatograms. Concentrated late-expiratory breath samples were collected from asthmatics, COPD subjects and healthy controls. In the asthmatic group, sputum induction with hypertonic saline, fraction exhaled nitric oxide (FeNO) measurement and asthma control questionnaire (ACQ) were performed. In COPD subjects, sputum induction and exacerbation frequency were collected. In the exhaled breath condensate (EBC) study, similar data were collected in asthmatics and healthy controls. Breath samples were analysed using gas chromatography time-of-flight mass spectrometry (GC-TOF-MS) while EBC was analysed using NMR spectroscopy. Discriminatory compounds or NMR spectral regions were identified by univariate logistic regression, followed by multivariate analysis: 1. principal component analysis (PCA); 2. multivariate logistic regression; 3. receiver operating characteristic (ROC) analysis. The reproducibility was assessed using intraclass correlation coefficient (ICC).Results: In the COPD exhaled breath study, 11 VOCs significantly discriminated the COPD and healthy controls with AUROC of 0.74. The AUROC for phenotype discrimination was 0.83, 0.90, 0.94, 0.96 and 0.97 for inhaled corticosteroid (ICS) use, sputum eosinophilia (1% and 2% cut-off), neutrophilia (median cut-off) and exacerbation frequency respectively. In the asthma study, 15 VOCs significantly discriminated the two groups with AUROC of 0.93. The AUROC for phenotype discrimination was 0.96, 0.98, 0.90 and 0.97 for ICS use, eosinophils (2% cut-off), neutrophils (40% cut-off) and asthma control respectively. In EBC analysis, AUROC for asthmatics vs controls comparison was 0.96. Phenotyping results in this study were less good: only ICS use and sputum neutrophilia (65% cut-off) were clearly classified with AUROC of 0.89 and 0.88 while eosinophilia (3% cut-off) and asthma control had poor discrimination; 0.69 and 0.62 respectively. Breath VOC reproducibility varied greatly depending on the class of compounds studied, while for the EBC analysis, reproducibility was moderate to very good (ICCs in the range of 0.42-0.99).Conclusions: We have demonstrated the ability of breath analysis in discriminating asthmatics and COPD subjects from controls. Exhaled breath analysis was also able to phenotype these patients based on steroid treatment, sputum inflammatory cells, exacerbation frequency and asthma control. This metabolomic approach could provide a novel, non-invasive method of diagnosing and phenotyping obstructive lung diseases in the future.
46

Role of physical activity in daily life in Chronic Obstructive Pulmonary Disease (COPD)

Mantoani, Leandro Cruz January 2018 (has links)
Background: Chronic obstructive pulmonary disease (COPD) is an important common chronic lung condition that is a leading cause of morbidity and mortality worldwide, resulting in a substantial and increasing economic and social burden to health care systems. Physical activity (PA) is the strongest predictor of mortality in this population, playing an important role determining the quality of life in COPD, with better outcomes being reported by those who have higher levels of PA. Therefore, improving PA levels has been considered a key component in the management of patients with COPD. Likewise, it is important to understand the mechanisms that lead to inactivity, as it is to develop accurate methods of measuring PA in this population. Aims of the thesis: 1) To identify and to summarize the interventions able to increase PA levels in patients with COPD; 2) To understand the longitudinal interaction between muscle mass and function and PA levels in COPD; 3) To study the acceptability and the suitability of a new activity monitor (TracMor D - Philips, the Netherlands) for home coaching in daily routine of patients with COPD; and 4) To investigate whether a PA enhancing programme with set targets and feedback would constitute a successful intervention to increase PA levels in patients with COPD attending pulmonary rehabilitation (PR). Methods: To achieve the first aim of the thesis I performed a systematic review summarizing interventional studies that assessed PA as an outcome in patients with COPD. For the second aim, I analysed some multicentric longitudinal data (one year follow-up) on PA and muscle mass/function in COPD. The third aim was achieved with a pilot study I conducted in Edinburgh, where patients with COPD wore three TracMor D in different body places simultaneously with the criterion method (Actigraph GT3x activity monitor) for a week. To accomplish the fourth and main aim of my PhD, I conducted a randomised controlled trial (RCT) where patients with COPD undergoing PR were randomised to either receive PR only or PR plus a PA coaching programme using the TracMor D activity monitor for 12 weeks. Main Results: Study 1: Sixty studies were considered for data extraction in the systematic review. Seven types of intervention with the potential to increase PA levels in patients with COPD were identified. PR programmes with more than 12 weeks of duration and PA coaching programmes with feedback of an activity monitor are promising interventions to increase activity levels in patients with COPD. Overall, the quality of evidence across interventional studies was graded as very low. Study 2: The longitudinal study showed that there were weak correlations between PA levels and muscle strength at baseline (0.19 ≤ r ≤ 0.33 p < 0.001 for all). No correlations were found between changes in PA and muscle strength (-509 [-1295-362] vs -0.4 [-3.5-2.6] - 12 months minus baseline - respectively) and future muscle mass (p > 0.05). Baseline PA levels are related to future muscle strength (0.30 ≤ r ≤ 0.41, p < .0001) but not with muscle mass. Study 3: This study showed that TracMor D had strong correlations with Actigraph GT3x in terms of Kcal consumption in all three positions (necklace, pocket and hip) (0.84 ≥ r < 0.86, p < 0.001 for all). TracMor D was considered comfortable and easy to use at home, receiving a mean usability score of 98 out of 100 maximum points. Study 4: My RCT showed that the proposed PA intervention was effective in changing steps/day (1251 ± 2408 vs control -410 ± 1118, p=0.01), time spent in light activities (21 ± 60 vs -37 ± 55, p=0.004), exercise capacity (99 ± 139 vs 3 ± 83 meters; 85 ± 114 vs 2 ± 62 seconds, p < 0.03 for both) and muscle strength (15 ± 20 vs -5 ± 18, p=0.01) among others when compared to the control group. Conclusions: Strategies focussing specifically on increasing PA and longer PR programmes may have greater impacts on PA levels in COPD. Well-designed clinical trials with objective assessment of PA in patients with COPD are needed. PA levels are not related to one-year changes in muscle mass and muscle strength in patients with COPD. However, higher PA levels at baseline are related to having higher muscle strength at one-year. TracMor D strongly correlated with the criterion method and was highly accepted by patients with COPD in their daily routine, being considered comfortable and easy to use at home. The combination of PR with a physical activity enhancing programme using a PA monitor to set targets and give feedback on activity levels significantly improves PA, exercise capacity, muscle strength, quality of life, and anxiety and depression levels in patients with COPD.
47

Small-Scale MDCT-Based Measures of Ventilation and Perfusion: the Development and Evaluation of New Tools for Examining the Etiology of Regional Lung Disease

Fuld, Matthew Kyle 01 July 2012 (has links)
Pulmonary diseases are characterized by small-scale and large-scale alterations in structure and function of the lung. Multidetector-row computed tomography (MDCT) is a powerful tool for quantitatively assessing small-scale lung structure including parenchymal destruction, air trapping and airway remodeling. When combined with novel imaging techniques and contrast agents, measuring small-scale regional ventilation (rV̇A) and perfusion (rQ̇) also becomes possible. This thesis focuses on developing and evaluating MDCT-based tools for measuring regional lung function in animal models and transitioning them to studying humans. Wash-in xenon-CT rV̇A measurements acquired in an animal model were validated with inhaled fluorescent microspheres (FMS), an invasive but recognized gold standard. Xenon-CT correlated well with FMS, demonstrating similar gradients in prone and supine postures. Small-scale rV̇A measurements from xenon-CT were less susceptible to partial voluming and resulted in reduced scatter. To facilitate the measurement of regional structure and function on awake-free-breathing humans, we developed systems for lung volume standardization during scanning for both static and dynamic breathing. Anesthetic properties dictated using 30% rather than 55% xenon-gas, reducing signal-to-noise ratio. This reduction, in addition to the influence of free breathing, made xenon-CT more susceptible to noise and required additional post-processing to bolster confidence in rV̇A measurements acquired in humans. Improvements to the available curve-fit algorithms were made and 4D image registration was developed to align time-series datasets. Applying these techniques, we compared rV̇A between normal never-smokers (NS), normal smokers (SNI), normal smokers with early signs of centrilobular emphysema not evident by PFTs (SCE) and smokers with COPD. There was increased heterogeneity in SNI versus NS and time constants were lengthened in COPD and in SCE. This is consistent with our earlier hypothesis that while patchy inflammation will occur in all smokers, only a subset of the population with decreased rQ̇ in regions of inflammation stemming from a failure to block HPV will be susceptible to emphysema. In order to facilitate translation into the clinical research environment, we established dual-energy-CT (DECT) methods to replace more elaborate time-series laboratory-centered techniques. Xe-DECT rV̇A measures were optimized through a series of phantom and animal studies to determine the proper three-material decomposition parameters, imaging parameters, gas mixture and delivery protocol. DECT perfused blood volume was validated as a surrogate for rQ̇ in animal studies in which blood flow patterns were altered by increasing lung inflation or occluding a portion of the pulmonary vasculature. To examine the intricacy of lung function, the effects of disease, and give us insight into their etiology we must study gas-exchange on a small-scale. MDCT-based techniques provide the spatial resolution necessary to examine rV̇A and rQ̇ on a small-scale offering an avenue to identify novel phenotypes that may not only yield insights into disease processes but also may provide tools leading to drug and device developments, outcomes assessment and ultimately to the selection of subpopulations suitable for a particular intervention.
48

Physical Activity and Veteran Status in Obesity and Chronic Obstructive Pulmonary Disease

Kren, Erin McGuire 01 January 2018 (has links)
There are few data available regarding the relationship between physical activity and veteran status in those with combined chronic obstructive pulmonary disease (COPD) and obesity. COPD is a common illness and a leading cause of death in the United States. Veterans represent a distinct subpopulation in the United States and are more likely to have COPD, which is a disease with a high rate of comorbidities such as obesity. Physical activity can improve outcomes for those with COPD and obesity. However, recommendations for physical activity for those with COPD and obesity are vague. This study, based on the self-determination theory, sought to explore the relationship between average weekly physical activity and veteran status while controlling for age, sex, race, ethnicity, smoking status, body mass index (BMI), education level, and annual household income in those with comorbid COPD and obesity. Also, the relationship between not meeting, meeting, and exceeding physical activity recommendations and veteran status, while accounting for variation in for age, sex, race, ethnicity, smoking status, BMI, education level, and annual household income, was explored. A case-control study was done to answer the research questions using multiple regression and ordinal regression analyses, respectively, using data from 1,430 participants from the 2015 BRFSS. Veteran status was not significantly associated with physical activity nor was it significantly associated with falling below, at, or above recommended physical activity amounts. However, it was found that increased BMI was associated with decreased physical activity. The results from this study can be used to inform policies, refine recommendations, and guide interventions for those with COPD and obesity.
49

Reducing Home Health COPD-Related 30-Day Hospital Readmissions Using Telehealth Technology

Stammer, Steven Eric 01 January 2018 (has links)
Chronic obstructive pulmonary disease (COPD) is a collection of chronic conditions that results in irreparable lung damage and stress to patients. COPD also has considerable financial impacts on health care entities due to frequent hospital readmissions of COPD patients. The Centers for Medicare and Medicaid Services penalize care entities for 30-day hospital readmissions. Many rehospitalizations attributed to COPD are due to exacerbations, often preceded by physiologic and emotional changes that can be monitored, allowing action to be taken to prevent readmissions. The practice problem for this quality improvement project explored whether the use of remote home monitoring of COPD patients discharged to home health care, coupled with the use of a medication rescue pack, would reduce rehospitalizations within 30 days after discharge. The purpose of the project was to evaluate the effectiveness of telehealth remote monitoring and initiation of a medication rescue pack in decreasing 30-day readmissions of COPD patients. The self-efficacy model was used to encourage health-promoting actions that are necessary for chronic disease management. Data from the project agency's records of COPD patients were evaluated for readmission rates. Analysis of the data from 8 preintervention patients showed that 3 (38%) were readmitted. Postintervention data showed that of the 9 participants, only 1 was readmitted (11%). Comparison of the data showed a 27% decrease in readmissions because of the intervention. The results of this project have the potential to bring about positive social change by improving care management remotely in real time, thus decreasing rehospitalization in COPD patients.
50

Att leva med kroniskt obstruktiv lungsjukdom :  Patienters beskrivning av sitt dagliga liv.

Bivall, Märta, Berntsson Nilsson, Helen January 2010 (has links)
Background; Chronic obstructive pulmonary disease (COPD) is a lung disease characterized by airway obstruction. Common signs of COPD are the slow process and shortness of breath on exertion. The most important treatment is to quit smoking. Most nurses, regardless of where they work, will meet these patients, often when the patients are having respiratory disorders. Aim; the aim of this study was to illuminate how patients with COPD describe the daily life based on how he/she experience and cope with the disease. Method; The study was designed as a literature review with aim to critically review and compile the results from ten qualitative and two quantitative articles. Results; Five themes emerged from the analysis of the articles, describing experiences of limitations, dependency, frustration, loss and life threatened. These experiences steered the patient's way to manage their disease. The management process could include changes in behavior, avoiding activities, symtom relief, adaption or acceptance. Conclusion; The main limitation was perceived as breathlessness, and the management of the disease was directed to mitigate this to try to live as unlimited as possible.

Page generated in 0.0752 seconds