| 1. |
- Calverley, Peter M, et al.
(författare)
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Early response to inhaled bronchodilators and corticosteroids as a predictor of 12-month treatment responder status and COPD exacerbations.
- 2016
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Ingår i: The International Journal of Chronic Obstructive Pulmonary Disease. - 1178-2005. ; 11, s. 381-390
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Tidskriftsartikel (refereegranskat)abstract
- Early treatment response markers, for example, improvement in forced expiratory volume in 1 second (FEV1) and St George's Respiratory Questionnaire (SGRQ) total score, may help clinicians to better manage patients with chronic obstructive pulmonary disease (COPD). We investigated the prevalence of clinically important improvements in FEV1 and SGRQ scores after 2-month budesonide/formoterol or formoterol treatment and whether such improvements predict subsequent improvements and exacerbation rates.
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| 2. |
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| 3. |
- Diaz, Sandra, et al.
(författare)
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Hyperpolarized (3)He apparent diffusion coefficient MRI of the lung: Reproducibility and volume dependency in healthy volunteers and patients with emphysema.
- 2008
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Ingår i: Journal of Magnetic Resonance Imaging. - : Wiley. - 1522-2586 .- 1053-1807. ; 27, s. 763-770
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To measure the apparent diffusion coefficient (ADC) of hyperpolarized (HP) (3)He gas using diffusion weighted MRI in healthy volunteers and patients with emphysema and examine the reproducibility and volume dependency. MATERIALS AND METHODS: A total of eight healthy volunteers and 16 patients with emphysema were examined after inhalation of HP (3)He gas mixed with nitrogen (N(2)) during breathhold starting from functional residual capacity (FRC) in supine position. Coronal diffusion-sensitized MR images were acquired. Each subject was imaged on three separate days over a seven-day period and received two different volumes (6% and 15% of total lung capacity [TLC]) of HP (3)He each day. ADC maps and histograms were calculated. The mean and standard deviation (SD) of the ADC at different days and volumes were compared. RESULTS: The reproducibility of the mean ADC and SD over several days was good in both healthy volunteers and patients (SD range of 0.003-0.013 cm(2)/second and 0.001-0.009 cm(2)/second at 6% and 15% of TLC for healthy volunteers, and a SD range of 0.001-0.041 cm(2)/second and 0.001-0.011 cm(2)/second, respectively, for patients). A minor but significant increase in mean ADC with increased inhaled gas volume was observed in both groups. CONCLUSION: Mean ADC and SD of HP (3)He MRI is reproducible and discriminates well between healthy controls and patients with emphysema at the higher gas volume. This method is robust and may be useful to gain new insights into the pathophysiology and course of emphysema. J. Magn. Reson. Imaging 2008. (c) 2008 Wiley-Liss, Inc.
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| 4. |
- Diaz, Sandra, et al.
(författare)
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Progression of Emphysema in a 12-month Hyperpolarized (3)He-MRI Study Lacunarity Analysis Provided a More Sensitive Measure than Standard ADC Analysis(1).
- 2009
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Ingår i: Academic Radiology. - : Elsevier BV. - 1878-4046 .- 1076-6332. ; 16:6, s. 700-707
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Tidskriftsartikel (refereegranskat)abstract
- RATIONALE AND OBJECTIVES: Inhaled hyperpolarized (3)He magnetic resonance (MR) imaging has been used to measure alveolar size in patients with emphysema. The aim of this study was to test the hypothesis that (3)He MR images could be used to develop a biomarker of emphysema progression. MATERIALS AND METHODS: Twelve healthy controls and 18 patients with emphysema (eight current smokers, 10 ex-smokers) were imaged at baseline and 6 and 12 months. An additional nine subjects with alpha-1 antitrypsin deficiency (four with emphysema, six without symptoms) were also imaged at baseline and at 6 months. Each subject was imaged at two lung volumes: functional residual capacity (FRC) and FRC plus 15% of total lung capacity. Means and standard deviations of apparent diffusion coefficients (ADCs) were calculated from coronal images of the entire lung and correlated with pulmonary function test results. The lacunarity hypothesis was tested and calculated from the data using a range of 2x2 x 2 to 6x6 x 6 voxels, and the average was calculated. RESULTS: There was no change in the mean ADC at either lung volume in any subject over the 6- or 12-month period. FRC and residual volume increased over the 12 months, suggesting air trapping. The lacunarity of images collected at FRC increased at 6 and 12 months in smokers only (P=.063 and P=.023, respectively). CONCLUSIONS: The mean ADC calculated from MR images of the lungs with helium was not sufficiently sensitive to detect changes over a 12-month period. However, lacunarity captured more of the spatial information in the images and detected emphysema progress in the smokers.
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| 5. |
- Diaz, Sandra, et al.
(författare)
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Validity of apparent diffusion coefficient hyperpolarized He-3-MRI using MSCT and pulmonary function tests as references
- 2009
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Ingår i: European Journal of Radiology. - : Elsevier BV. - 1872-7727 .- 0720-048X. ; 71:2, s. 257-263
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To compare apparent diffusion coefficient (ADC) measurements from hyperpolarized (HP) helium (He-3)-magnetic resonance imaging (MRI) with quantitative data from multislice Computed Tomography (CT) (MSCT) of the whole lungs and pulmonary function tests (PFT). Materials and methods: Twenty-seven subjects, 22 with established emphysema and 5 with preclinical emphysema defined by PFT criteria, were examined with Hp He-3-MRI and MSCT. Mean age was 55 (+/- 12) years, 18 female and 9 male. Mean ADC from He-3-MRI was compared with emphysema index (EI), 15th percentile and mean lung density (MLD) values from MSCT. Both mean ADC and MSCT data were compared to PFT, especially percent of predicted diffusing capacity of carbon monoxide (%predicted DLCO), using Pearson's correlation test. Results: Mean ADC and standard deviation values were 0.392 +/- 0.119 cm(2)/s for the established emphysema group and 0.216 +/- 0.046 for the pre-clinical emphysema group. MSCT values for the established emphysema group and pre-clinical emphysema group were: EI (%) 11 +/- 12 and 0.4 +/- 0.6, respectively; 15th percentile (Hounsfield Units (HU)), -956 +/- 25 and -933 +/- 13, respectively and MLD (HU) -877 +/- 20 and -863 +/- 15, respectively. Correlations between mean ADC and El and 15th percentile were both r=0.90 and for MLD r=0.59. There was higher correlation between mean ADC and %predicted DLCO (r=0.90) than between El and %predicted DLCO (r=0.76). Conclusion: Hp He-3-MRI correlates well with density measurements from MSCT and agrees better than MSCT with %predicted DLCO which is the PFT most related to emphysema. (C) 2008 Elsevier Ireland Ltd. All rights reserved.
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| 7. |
- Hughes, Joseph L, et al.
(författare)
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Photoconversion of chlorophylls in higher-plant CP43 characterized by persistent spectral hole burning at 1.7 K.
- 2004
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Ingår i: Journal of Luminescence. - : Elsevier BV. - 0022-2313. ; 108:1-4, s. 131-136
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Tidskriftsartikel (refereegranskat)abstract
- The chorophyll-protein complex CP43 is a proximal-antenna subunit important for excitation energy transfers from peripheral light-harvesting antenna to the Photosystem II (PSII) reaction centre. We report persistent spectral hole burning at 1.7 K in the Qy(0,0) origin and Qy(1,0) vibrational satellite bands of chorophyll a (chl a) in CP43 isolated from higher plants. The isolated CP43 is known to possess two quasi-degenerate 'red' trap states. We find persistent hole burning in the primary trap exhibits a photoconversion property, with a photoproduct located well outside its inhomogeneous distribution. This photoconversion of trap chl a molecules also occurs with non-selective white light illumination. The contribution of the 'red' states to CP43 absorption is discussed.
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| 8. |
- Hughes, Joseph L, et al.
(författare)
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The Native Reaction Centre of Photosystem II: A New Paradigm for P680
- 2004
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Ingår i: Australian Journal of Chemistry. - 0004-9425. ; 57:12, s. 1179-1183
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Tidskriftsartikel (refereegranskat)abstract
- Low-temperature spectra of fully active (oxygen-evolving) Photosystem II (PSII) cores prepared from spinach exhibit well developed structure. Spectra of isolated sub-fragments of PSII cores establish that the native reaction centre is better structured and red-shifted compared to the isolated reaction centre. Laser illumination of PSII cores leads to efficient and deep spectral hole-burning. Measurements of homogeneous hole-widths establish excited-state lifetimes in the 40–300 ps range. The high hole-burning efficiency is attributed to charge separation of P680 in native PSII that follows reaction-centre excitation via ‘slow transfer’ states in the inner light-harvesting assemblies CP43 and CP47. The ‘slow transfer’ state in CP47 and that in CP43 can be distinguished in the hole-burning action spectrum and high-resolution hole-burning spectra. An important observation is that 685–700 nm illumination gives rise to efficient P680 charge separation, as established by QA− formation. This leads to a new paradigm for P680. The charge-separating state has surprisingly weak absorption and extends to 700 nm.
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| 9. |
- Jenkins, Christine R, et al.
(författare)
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Reliever salbutamol use as a measure of exacerbation risk in chronic obstructive pulmonary disease.
- 2015
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Ingår i: BMC Pulmonary Medicine. - : Springer Science and Business Media LLC. - 1471-2466. ; 15
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Tidskriftsartikel (refereegranskat)abstract
- Debate exists regarding which endpoints most sensitively reflect day-to-day variation in chronic obstructive pulmonary disease (COPD) symptoms and are most useful in clinical practice to predict COPD exacerbations. We hypothesized that short-acting β2-agonist (SABA) reliever use would predict short- and long-term exacerbation risk in COPD patients.
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| 10. |
- Make, Barry J., et al.
(författare)
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A score to predict short-term risk of COPD exacerbations (SCOPEX)
- 2015
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Ingår i: The International Journal of Chronic Obstructive Pulmonary Disease. - 1176-9106 .- 1178-2005. ; 10, s. 201-209
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Tidskriftsartikel (refereegranskat)abstract
- Background: There is no clinically useful score to predict chronic obstructive pulmonary disease (COPD) exacerbations. We aimed to derive this by analyzing data from three existing COPD clinical trials of budesonide/formoterol, formoterol, or placebo in patients with moderate-tovery- severe COPD and a history of exacerbations in the previous year.Methods: Predictive variables were selected using Cox regression for time to first severe COPD exacerbation. We determined absolute risk estimates for an exacerbation by identifying variables in a binomial model, adjusting for observation time, study, and treatment. The model was further reduced to clinically useful variables and the final regression coefficients scaled to obtain risk scores of 0-100 to predict an exacerbation within 6 months. Receiver operating characteristic (ROC) curves and the corresponding C-index were used to investigate the discriminatory properties of predictive variables.Results: The best predictors of an exacerbation in the next 6 months were more COPD maintenance medications prior to the trial, higher mean daily reliever use, more exacerbations during the previous year, lower forced expiratory volume in 1 second/forced vital capacity ratio, and female sex. Using these risk variables, we developed a score to predict short-term (6-month) risk of COPD exacerbations (SCOPEX). Budesonide/formoterol reduced future exacerbation risk more than formoterol or as-needed short-acting beta(2)-agonist (salbutamol).Conclusion: SCOPEX incorporates easily identifiable patient characteristics and can be readily applied in clinical practice to target therapy to reduce COPD exacerbations in patients at the highest risk.
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