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Search Results: 1 - 10 of 449138 matches for " J?rgen L. Olsen "
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Relation between Seasonally Detrended Shortwave Infrared?Reflectance Data and Land Surface Moisture in Semi?Arid Sahel
Jrgen L. Olsen,Pietro Ceccato,Simon R. Proud,Rasmus Fensholt,Manuela Grippa,Eric Mougin,Jonas Ard?,Inge Sandholt
Remote Sensing , 2013, DOI: 10.3390/rs5062898
Abstract: In the Sudano-Sahelian areas of Africa droughts can have serious impacts on natural resources, and therefore land surface moisture is an important factor. Insufficient conventional sites for monitoring land surface moisture make the use of Earth Observation data for this purpose a key issue. In this study we explored the potential of using reflectance data in the Red, Near Infrared (NIR), and Shortwave Infrared (SWIR) spectral regions for detecting short term variations in land surface moisture in the Sahel, by analyzing data from three test sites and observations from the geostationary Meteosat Second Generation (MSG) satellite. We focused on responses in surface reflectance to soil- and surface moisture for bare soil and early to mid- growing season. A method for implementing detrended time series of the Shortwave Infrared Water Stress Index (SIWSI) is examined for detecting variations in vegetation moisture status, and is compared to detrended time series of the Normalized Difference Vegetation Index (NDVI). It was found that when plant available water is low, the SIWSI anomalies increase over time, while the NDVI anomalies decrease over time, but less systematically. Therefore SIWSI may carry important complementary information to NDVI in terms of vegetation water status, and can provide this information with the unique combination of temporal and spatial resolution from optical geostationary observations over Sahel. However, the relation between SIWSI anomalies and periods of water stress were not found to be sufficiently robust to be used for water stress detection.
Study design: Evaluating gene–environment interactions in the etiology of breast cancer – the WECARE study
Jonine L Bernstein, Bryan Langholz, Robert W Haile, Leslie Bernstein, Duncan C Thomas, Marilyn Stovall, Kathleen E Malone, Charles F Lynch, Jrgen H Olsen, Hoda Anton-Culver, Roy E Shore, John D Boice, Gertrud S Berkowitz, Richard A Gatti, Susan L Teitelbaum, Susan A Smith, Barry S Rosenstein, Anne-Lise B?rresen-Dale, Patrick Concannon, W Douglas Thompson
Breast Cancer Research , 2004, DOI: 10.1186/bcr771
Abstract: To examine the joint roles of radiation exposure and genetic susceptibility in the etiology of breast cancer, we designed a case-control study nested within five population-based cancer registries. We hypothesized that a woman carrying a mutant allele in one of these genes is more susceptible to radiation-induced breast cancer than is a non-carrier. In our study, 700 women with asynchronous bilateral breast cancer were individually matched to 1400 controls with unilateral breast cancer on date and age at diagnosis of the first breast cancer, race, and registry region, and counter-matched on radiation therapy. Each triplet comprised two women who received radiation therapy and one woman who did not. Radiation absorbed dose to the contralateral breast after initial treatment was estimated with a comprehensive dose reconstruction approach that included experimental measurements in anthropomorphic and water phantoms applying patient treatment parameters. Blood samples were collected from all participants for genetic analyses.Our study design improves the potential for detecting gene–environment interactions for diseases when both gene mutations and the environmental exposures of interest are rare in the general population. This is particularly applicable to the study of bilateral breast cancer because both radiation dose and genetic susceptibility have important etiologic roles, possibly by interactive mechanisms. By using counter-matching, we optimized the informativeness of the collected dosimetry data by increasing the variability of radiation dose within the case–control sets and enhanced our ability to detect radiation–genotype interactions.The WECARE (for Women's Environmental Cancer and Radiation Epidemiology) Study is a multi-center, population-based case-control study of breast cancer designed to examine the interaction of gene carrier status and radiation exposure in the etiology of breast cancer. We are currently focusing on three major breast cancer suscepti
The varied rate of response to dietary intervention in autistic children  [PDF]
Jrgen Klaveness, Jay Bigam, Karl L. Reichelt
Open Journal of Psychiatry (OJPsych) , 2013, DOI: 10.4236/ojpsych.2013.32A009
Abstract:

Exorphins from casein and gluten have been found by HPLC and mass spectroscopy with fragmentation pattern in quickly frozen urine. Removing the proteins that contain these peptides, by dietary intervention has been tried with behavioral effects. We wanted to know how fast such changes take place. Method: Parents and caregivers filled out ATEC scores (Autism treatment evaluation checklist) over time so that changes in scores could be registered. Results: In this group of children who all responded to diet the time required for a positive effect was months rather than weeks. Conclusion: Short term interventions are probably a waste of time and money, and at least 3 - 6 months trials seem to be necessary.

Evidence for Impaired CARD15 Signalling in Crohn's Disease without Disease Linked Variants
Jakob Benedict Seidelin,Oliver Jay Broom,Jrgen Olsen,Ole Haagen Nielsen
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0007794
Abstract: Sensing of muramyl dipeptide (MDP) is impaired in Crohn's disease (CD) patients with disease-linked variants of the CARD15 (caspase activation and recruitment domain 15) gene. Animal studies suggest that normal CARD15 signalling prevents inflammatory bowel disease, and may be important for disease development in CD. However, only a small fraction of CD patients carry the disease linked CARD15 variants. The aim of this study was thus to investigate if changes could be found in CARD15 signalling in patients without disease associated CARD15 variants.
Influence of Smoking on Colonic Gene Expression Profile in Crohn's Disease
Ole Haagen Nielsen, Jacob Tveiten Bjerrum, Claudio Csillag, Finn Cilius Nielsen, Jrgen Olsen
PLOS ONE , 2009, DOI: 10.1371/journal.pone.0006210
Abstract: Background The development and course of Crohn's disease (CD) is related to both genetic and environmental factors. Smoking has been found to exacerbate the course of CD by increasing the risk of developing fistulas and strictures as well as the need for surgery, possibly because of an interaction between smoking or nicotine on macrophage function and the intestinal microvasculature. Several genes are involved in the pathogenesis of CD, and in this study the gene expression differences of the descending colonic mucosa were investigated in CD (smokers or never smokers) and controls (smokers or never smokers). Aim To identify any difference in gene expression of the descending colonic mucosa between smoking and never-smoking CD patients (and controls) by determining genetic expression profiles from microarray analysis. Methods Fifty-seven specimens were obtained by routine colonoscopy from the included material: CD smokers (n = 28) or never-smokers (n = 14) as compared to fifteen healthy controls (8 smokers and 7 never-smokers). RNA was isolated and gene expression assessed with Affymetrix GeneChip Human Genome U133 Plus 2.0. Data were analyzed by principal component analysis (PCA), Wilcoxon rank sum test and multiple linear regressions. Real-time (RT) PCR was subsequently applied to verify microarray results. Results The PCA analysis showed no intrinsic clustering of smokers versus never-smokers. However, when Wilcoxon rank sum test corrected with Q values were performed, six known genes were significantly expressed differently in the inflamed CD smokers as compared to the inflamed CD never-smokers: ring finger protein 138 (RNF138), metalothionein 2A (MT2A) and six transmembrane epithelial antigen of the prostate 3 (STEAP3), SA hypertension-associated homolog, PGM2L1 and KCNJ2. The subsequent RT-PCR-analyses verified, however, that only RNF138, MT2A and STEAP3 were significantly up-regulated in CD smokers in specimens with inflammatory activity of the descending colon. Conclusions The present study demonstrates that the genes, RNF138, MT2A, and STEAP3 are differently expressed in the inflamed descending colon of smoking versus never-smoking CD patients, which might be of relevance for the poorer clinical course among CD smokers. Many gastroenterologists are still not totally aware of the benefits of smoking cessation in relation to CD, and do not put much effort into getting the patients to quit, therefore more information on the negative effects of smoking, seems warranted.
Risks for Central Nervous System Diseases among Mobile Phone Subscribers: A Danish Retrospective Cohort Study
Joachim Schüz, Gunhild Waldemar, Jrgen H. Olsen, Christoffer Johansen
PLOS ONE , 2009, DOI: 10.1371/journal.pone.0004389
Abstract: The aim of this study was to investigate a possible link between cellular telephone use and risks for various diseases of the central nervous system (CNS). We conducted a large nationwide cohort study of 420 095 persons whose first cellular telephone subscription was between 1982 and 1995, who were followed through 2003 for hospital contacts for a diagnosis of a CNS disorder. Standardized hospitalization ratios (SHRs) were derived by dividing the number of hospital contacts in the cohort by the number expected in the Danish population. The SHRs were increased by 10–20% for migraine and vertigo. No associations were seen for amyotrophic lateral sclerosis, multiple sclerosis or epilepsy in women. SHRs decreased by 30–40% were observed for dementia (Alzheimer disease, vascular and other dementia), Parkinson disease and epilepsy among men. In analyses restricted to subscribers of 10 years or more, the SHRs remained similarly increased for migraine and vertigo and similarly decreased for Alzheimer disease and other dementia and epilepsy (in men); the other SHRs were close to unity. In conclusion, the excesses of migraine and vertigo observed in this first study on cellular telephones and CNS disease deserve further attention. An interplay of a healthy cohort effect and reversed causation bias due to prodromal symptoms impedes detection of a possible association with dementia and Parkinson disease. Identification of the factors that result in a healthy cohort might be of interest for elucidation of the etiology of these diseases.
Mapping of HNF4α target genes in intestinal epithelial cells
Mette Boyd, Simon Bressendorff, Jette M?ller, Jrgen Olsen, Jesper T Troelsen
BMC Gastroenterology , 2009, DOI: 10.1186/1471-230x-9-68
Abstract: We have performed a ChIP-chip analysis of the human intestinal cell line Caco-2 in order to make a genome-wide identification of HNF4α binding to promoter regions. The HNF4α ChIP-chip data was matched with gene expression and histone H3 acetylation status of the promoters in order to identify HNF4α binding to actively transcribed genes with an open chromatin structure.1,541 genes were identified as potential HNF4α targets, many of which have not previously been described as being regulated by HNF4α. The 1,541 genes contributed significantly to gene ontology (GO) pathways categorized by lipid and amino acid transport and metabolism. An analysis of the homeodomain transcription factor Cdx-2 (CDX2), the disaccharidase trehalase (TREH), and the tight junction protein cingulin (CGN) promoters verified that these genes are bound by HNF4α in Caco2 cells. For the Cdx-2 and trehalase promoters the HNF4α binding was verified in mouse small intestine epithelium.The HNF4α regulation of the Cdx-2 promoter unravels a transcription factor network also including HNF1α, all of which are transcription factors involved in intestinal development and gene expression.The intestinal epithelium continuously renews its cells by division of a stem/progenitor cell population located in the crypts. The daughter cells rapidly expand by cell divisions and migrate from the crypt to villus. The cells finally differentiate into the mature cell types of the intestine. In the small intestine these cells are enterocytes, paneth cells, goblet cells, and enteroendocrine cells. In the colon two major cell types predominate: colonocytes and goblet cells. The differentiation state of the intestinal cells can be determined by their location on the crypt/villus axis. Cells located in the bottom of the crypts are undifferentiated and proliferate (except for the paneth cells, which are located in the very bottom of the crypt). The cells located in the upper crypt and on the villus are differentiated and expres
Geomagnetic observations on Tristan da Cunha, South Atlantic Ocean
Jürgen Matzka,Nils Olsen,Cathrine Fox Maule,Lars William Pedersen
Annals of Geophysics , 2009, DOI: 10.4401/ag-4633
Abstract: Few geomagnetic ground observations exist of the Earth’s strongest core field anomaly, the South Atlantic Anomaly (SAA). The geomagnetic repeat station on the island Tristan da Cunha, located half-way between South Africa and South America at 37° 05’ S, 12° 18’ W, is therefore of crucial importance. We have conducted several sets of repeat station measurements during magnetically quiet conditions (Kp 2o or less) in 2004. The procedures are described and the results are compared to those from earlier campaigns and to the predictions of various global field models. Features of the local crustal bias field and the solar quiet daily variation are discussed. We also evaluate the benefit of continuous magnetic field recordings from Tristan da Cunha, and argue that such a data set is a very valuable addition to geomagnetic satellite data. Recently, funds were set up to establish and operate a magnetometer station on Tristan da Cunha during the Swarm magnetic satellite mission (2011-2014).
Phosphorylation Variation during the Cell Cycle Scales with Structural Propensities of Proteins
Stefka Tyanova,Jürgen Cox,Jesper Olsen,Matthias Mann,Dmitrij Frishman
PLOS Computational Biology , 2013, DOI: 10.1371/journal.pcbi.1002842
Abstract: Phosphorylation at specific residues can activate a protein, lead to its localization to particular compartments, be a trigger for protein degradation and fulfill many other biological functions. Protein phosphorylation is increasingly being studied at a large scale and in a quantitative manner that includes a temporal dimension. By contrast, structural properties of identified phosphorylation sites have so far been investigated in a static, non-quantitative way. Here we combine for the first time dynamic properties of the phosphoproteome with protein structural features. At six time points of the cell division cycle we investigate how the variation of the amount of phosphorylation correlates with the protein structure in the vicinity of the modified site. We find two distinct phosphorylation site groups: intrinsically disordered regions tend to contain sites with dynamically varying levels, whereas regions with predominantly regular secondary structures retain more constant phosphorylation levels. The two groups show preferences for different amino acids in their kinase recognition motifs - proline and other disorder-associated residues are enriched in the former group and charged residues in the latter. Furthermore, these preferences scale with the degree of disorderedness, from regular to irregular and to disordered structures. Our results suggest that the structural organization of the region in which a phosphorylation site resides may serve as an additional control mechanism. They also imply that phosphorylation sites are associated with different time scales that serve different functional needs.
Lack of Replication of the GRIN2A-by-Coffee Interaction in Parkinson Disease
Isma?l Ahmed equal contributor,Pei-Chen Lee equal contributor,Christina M. Lill equal contributor,Susan Searles Nielsen equal contributor,Fanny Artaud,Lisa G. Gallagher,Marie-Anne Loriot,Claire Mulot,Magali Nacfer,Tian Liu,Joanna M. Biernacka,Sebastian Armasu,Kari Anderson,Federico M. Farin,Christina Funch Lassen,Johnni Hansen,Jrgen H. Olsen,Lars Bertram,Demetrius M. Maraganore,Harvey Checkoway,Beate Ritz ?,Alexis Elbaz ?
PLOS Genetics , 2014, DOI: doi/10.1371/journal.pgen.1004788
Abstract:
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