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| 2. |
- Heitmann, J, et al.
(författare)
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Sympathetic activity is reduced by nCPAP in hypertensive obstructive sleep apnoea patients.
- 2004
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Ingår i: The European respiratory journal : official journal of the European Society for Clinical Respiratory Physiology. - 0903-1936. ; 23:2, s. 255-62
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Tidskriftsartikel (refereegranskat)abstract
- There is increasing evidence that nasal continuous positive airway pressure (nCPAP) lowers blood pressure in obstructive sleep apnoea (OSA) patients, not only during sleep but also in the daytime. However, both the mechanisms of blood pressure reduction and the considerable differences in the magnitude of the effect in the studies presented to date are not fully understood. Therefore, the authors prospectively studied the effect of nCPAP on noradrenaline plasma levels (NApl), blood pressure and heart rate (HR) in 10 normotensive and eight hypertensive OSA patients before and after 41.6 +/- 16.9 days of nCPAP therapy. Polysomnography and invasive blood pressure were continuously monitored over 24 h in the supine position before and with nCPAP. NApl were analysed every 15 min. In hypertensives, nCPAP reduced NApl by 36 +/- 25%, lowered mean arterial blood pressure substantially (night-time: -8.89 +/- 14.09 mmHg; daytime: -7.94 +/- 10.47 mmHg) and decreased HR by 6.6 +/- 5.4 beats x min(-1), whereas in normotensives there were only minor changes. The decrease in heart rate was associated with a decrease in mean arterial blood pressure and noradrenaline plasma levels, suggesting a causal effect of nasal continuous positive airway pressure therapy. This nasal continuous positive airway pressure effect occurs mainly in hypertensive obstructive sleep apnoea patients, whereas the effect is small in normotensives. This may explain, at least in part, some of the discrepant results in previous treatment studies.
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| 3. |
- Papaspiropoulos, Giorgos, et al.
(författare)
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Aerosol elemental concentrations in the tropopause region from intercontinental flights with the Civil Aircraft for Regular Investigation of the Atmosphere Based on an Instrument Container (CARIBIC) platform
- 2002
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Ingår i: Journal of Geophysical Research: Atmospheres. - 2169-897X. ; 107:D23
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Tidskriftsartikel (refereegranskat)abstract
- This study with the Civil Aircraft for Regular Investigation of the Atmosphere Based on an Instrument Container (CARIBIC) platform investigates the aerosol elemental concentrations at 9-11 km altitude in the northern hemisphere. Measurements from 31 intercontinental flights over a 2-year period between Germany and Sri Lanka/Maldives in the Indian Ocean are presented. Aerosol samples were collected with an impaction technique and were analyzed for the concentration of 18 elements using particle-induced X-ray emission (PIXE). Additional measurements of particle number concentrations, ozone and carbon monoxide concentrations, and meteorological modeling were included in the interpretation of the aerosol elemental concentrations. Particulate sulphur was found to be by far the most abundant element. Its upper tropospheric concentration increased, on average, by a factor of 2 from the tropics to midlatitudes, with another factor 2 higher concentrations in the lowermost stratosphere over midlatitudes. Correlation patterns and source profiles suggest contributions from crustal sources and biomass burning, but not from meteor ablation. Coinciding latitudinal gradients in particulate sulphur concentrations and emissions suggest that fossil fuel combustion is an important source of the aerosol in the upper troposphere and lowermost stratosphere. The measurements indicate aerosol transport along isentropic surfaces across the tropopause into the lowermost stratosphere. As a result of the prolonged residence time, ageing via oxidation of sulphur dioxide in the lowermost stratosphere was found to be a likely high-altitude, strong source that, along with downward transport of stratospheric air, could explain the vertical gradient of particulate sulphur mass concentration around the extratropical tropopause.
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| 4. |
- Bjarklev, A., et al.
(författare)
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Liquid crystal photonic crystal fiber
- 2004
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Ingår i: Optics InfoBase Conference Papers. ; FiO-2004
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Konferensbidrag (refereegranskat)abstract
- A new class of hybrid photonic crystal fibers infiltrated with liquid crystals offers novel functionalities and ultimately takes full advantage of the different waveguiding effects demonstrated today. Among the most interesting possibilities, we demonstrate 'distributed' tunable filter and switching functionalities operating by the photonic bandgap effect.
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| 5. |
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| 6. |
- Flinn, Elizabeth M, et al.
(författare)
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Recruitment of Gen5-containing complexes during c-Myc-dependent gene activation - Structure and function aspects
- 2002
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Ingår i: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 277:26, s. 23399-23406
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Tidskriftsartikel (refereegranskat)abstract
- The N-terminal domain of c-Myc plays a key role in cellular transformation and is involved in both activation and repression of target genes as well as in modulated proteolysis of c-Myc via the proteasome. Given this functional complexity, it has been difficult to clarify the structures within the N terminus that contribute to these different processes as well as the mechanisms by which they function. We have used a simplified yeast model system to identify the primary determinants within the N terminus for W chromatin remodeling of a promoter, (ii) gene activation from a chromatin template in vivo, and (iii) interaction with highly purified Gcn5 complexes as well as other chromatin-remodeling complexes in vitro. The results identify two regions that contain autonomous chromatin opening and gene activation activity, but both regions are required for efficient interaction with chromatin-remodeling complexes in vitro. The conserved Myc boxes do not play a direct role in gene activation, and Myc box II is not generally required for in vitro interactions with remodeling complexes. The yeast SAGA complex, which is orthologous to the human GCN5-TRRAP complex that interacts with Myc in human cells, plays a role in Myc-mediated chromatin opening at the promoter but may also be involved in later steps of gene activation.
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| 7. |
- Heintzenberg, J, et al.
(författare)
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Number and sulfur derived 3-parameter aerosol size distributions in the tropopause region from CARIBIC flights between Germany and the Indic
- 2002
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Ingår i: Journal of Aerosol Science. - 0021-8502. ; 33:4, s. 595-608
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Tidskriftsartikel (refereegranskat)abstract
- Aerosol number concentrations in three size ranges (d(p) > 4, d(p) > 12, 18 less than or equal to, dp less than or equal to, 135 nm) and sulfur mass from impactor samples were collected over a total of about 120 sampling hours on 18 long-range commercial flights between the northern mid-latitudes and the equatorial region covering an altitude range between 8.8 and 11.2 km. The data were evaluated with a new random search algorithm to derive monomodal lognormal particle size distributions. Through tests of the algorithm using synthetic data and size distributions from mountain stations the retrieval capabilities of the fitting algorithm are established. The fitting of aerosol data yields three parameters of the submicrometer size distribution. Their latitudinal trends indicate the influence of tropical and mid-latitudinal source regions on the tropopause aerosol. Total particle numbers show maxima near tropical biomass burning, and over the European regions. Geometric mean diameters decrease north of 35degreesN while the width of the distribution increases, indicating a move towards more frequent recent nucleation events or more frequent bimodal size distributions. (C) 2002 Elsevier Science Ltd. All rights reserved.
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| 8. |
- Kyle, Ursula G, et al.
(författare)
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Bioelectrical impedance analysis--part I: review of principles and methods.
- 2004
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Ingår i: Clinical nutrition (Edinburgh, Scotland). - : Elsevier BV. - 0261-5614. ; 23:5, s. 1226-43
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Forskningsöversikt (refereegranskat)abstract
- The use of bioelectrical impedance analysis (BIA) is widespread both in healthy subjects and patients, but suffers from a lack of standardized method and quality control procedures. BIA allows the determination of the fat-free mass (FFM) and total body water (TBW) in subjects without significant fluid and electrolyte abnormalities, when using appropriate population, age or pathology-specific BIA equations and established procedures. Published BIA equations validated against a reference method in a sufficiently large number of subjects are presented and ranked according to the standard error of the estimate. The determination of changes in body cell mass (BCM), extra cellular (ECW) and intra cellular water (ICW) requires further research using a valid model that guarantees that ECW changes do not corrupt the ICW. The use of segmental-BIA, multifrequency BIA, or bioelectrical spectroscopy in altered hydration states also requires further research. ESPEN guidelines for the clinical use of BIA measurements are described in a paper to appear soon in Clinical Nutrition.
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| 9. |
- Kyle, Ursula G, et al.
(författare)
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Bioelectrical impedance analysis-part II: utilization in clinical practice.
- 2004
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Ingår i: Clinical nutrition (Edinburgh, Scotland). - : Elsevier BV. - 0261-5614. ; 23:6, s. 1430-53
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Forskningsöversikt (refereegranskat)abstract
- BIA is easy, non-invasive, relatively inexpensive and can be performed in almost any subject because it is portable. Part II of these ESPEN guidelines reports results for fat-free mass (FFM), body fat (BF), body cell mass (BCM), total body water (TBW), extracellular water (ECW) and intracellular water (ICW) from various studies in healthy and ill subjects. The data suggests that BIA works well in healthy subjects and in patients with stable water and electrolytes balance with a validated BIA equation that is appropriate with regard to age, sex and race. Clinical use of BIA in subjects at extremes of BMI ranges or with abnormal hydration cannot be recommended for routine assessment of patients until further validation has proven for BIA algorithm to be accurate in such conditions. Multi-frequency- and segmental-BIA may have advantages over single-frequency BIA in these conditions, but further validation is necessary. Longitudinal follow-up of body composition by BIA is possible in subjects with BMI 16-34 kg/m(2) without abnormal hydration, but must be interpreted with caution. Further validation of BIA is necessary to understand the mechanisms for the changes observed in acute illness, altered fat/lean mass ratios, extreme heights and body shape abnormalities.
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| 11. |
- van Kuilenburg, André B P, et al.
(författare)
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Novel disease-causing mutations in the dihydropyrimidine dehydrogenase gene interpreted by analysis of the three-dimensional protein structure
- 2002
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Ingår i: Biochemical Journal. - : Portland Press Ltd.. - 0264-6021 .- 1470-8728. ; 364:Pt 1, s. 157-163
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Tidskriftsartikel (refereegranskat)abstract
- Dihydropyrimidine dehydrogenase (DPD) deficiency is an autosomal recessive disease characterized by thymine-uraciluria in homozygous deficient patients. Cancer patients with a partial deficiency of DPD are at risk of developing severe life-threatening toxicities after the administration of 5-fluorouracil. Thus, identification of novel disease-causing mutations is of the utmost importance to allow screening of patients at risk. In eight patients presenting with a complete DPD deficiency, a considerable variation in the clinical presentation was noted. Whereas motor retardation was observed in all patients, no patients presented with convulsive disorders. In this group of patients, nine novel mutations were identified including one deletion of two nucleotides [1039-1042delTG] and eight missense mutations. Analysis of the crystal structure of pig DPD suggested that five out of eight amino acid exchanges present in these patients with a complete DPD deficiency, Pro86Leu, Ser201Arg, Ser492Leu, Asp949Val and His978Arg, interfered directly or indirectly with cofactor binding or electron transport. Furthermore, the mutations Ile560Ser and Tyr211Cys most likely affected the structural integrity of the DPD protein. Only the effect of the Ile370Val and a previously identified Cys29Arg mutation could not be readily explained by analysis of the three-dimensional structure of the DPD enzyme, suggesting that at least the latter might be a common polymorphism. Our data demonstrate for the first time the possible consequences of missense mutations in the DPD gene on the function and stability of the DPD enzyme.
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