| 441. |
- Dahlqvist, Ralf, 1973, et al.
(författare)
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Association of calcium with colloidal particles and speciation of calcium in the Kalix and Amazon rivers
- 2004
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Ingår i: Geochimica Et Cosmochimica Acta. - : Elsevier BV. - 0016-7037 .- 1872-9533. ; 68:20, s. 4059-4075
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Tidskriftsartikel (refereegranskat)abstract
- A considerable amount of colloidally bound Ca has been detected in water samples from Amazonian rivers and the Kalix River, a sub-arctic boreal river. Fractionation experiments using several analytical techniques and processing tools were conducted in order to elucidate the matter. Results show that on average 84% of the total Ca concentration is present as free Ca. Particulate, colloidal and complexed Ca constitute the remaining 16%, of which the colloidal fraction is significant. Ultrafiltration experiments show that the colloidal fraction in the sampled Amazonian rivers and the Kalix River range between 1% and 25%. In both the Amazonian and the Kalix rivers the technique of cross-flow ultrafiltration was used to isolate particles and colloids. The difference in concentration measured with ICP-AES and a Ca ion-selective electrode in identical samples was used to define the free Ca concentration and thus indirectly the magnitude of the particulate, colloidal and complexed fractions. Results from the Kalix and Amazonian rivers are in excellent agreement. Furthermore, the results show that the colloidal concentrations of Ca can be greatly overestimated (up to 227%) when conventional analysis and calculation of ultrafiltration data is used due to retention of free Ca ions during the ultrafiltration process. Calculation methods for colloidal matter are presented in this work, using complementary data from ISE analysis. In the Kalix River temporal changes in the fractionation of Ca were studied before, during and after a spring-flood event. Changes in the size distribution of colloidally associated Ca was studied using FlFFF (Flow Field-Flow Fractionation) coupled on-line to a HR ICP-MS. The FlFFF-HR ICP-MS fractograms clearly show the colloidal component of Ca, supporting the ultrafiltration findings. During winter conditions the size distribution of colloidally associated Ca has a concentration maximum at similar to5 to 10 nm in diameter, shifting to smaller sizes (<5 mm) during and after the spring flood. This shift in size distribution follows a change in the river during this period from ironoxyhydroxy colloids being the most important colloidal carrier phase to humic substances during and after the spring flood. WHAM and NICA-Donnan models were used to calculate the amount of colloidally bound Ca. The results similar for both models, show that on average 16% of the Ca may be associated to a colloidal phase, which is in broad agreement with the measurements. Copyright (C) 2004 Elsevier Ltd.
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| 442. |
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| 443. |
- Damas, Joana, et al.
(författare)
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Evolution of the ancestral mammalian karyotype and syntenic regions
- 2022
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences (PNAS). - 0027-8424 .- 1091-6490. ; 119:40
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Tidskriftsartikel (refereegranskat)abstract
- Decrypting the rearrangements that drive mammalian chromosome evolution is critical to understanding the molecular bases of speciation, adaptation, and disease susceptibility. Using 8 scaffolded and 26 chromosome-scale genome assemblies representing 23/26 mammal orders, we computationally reconstructed ancestral karyotypes and syntenic relationships at 16 nodes along the mammalian phylogeny. Three different reference genomes (human, sloth, and cattle) representing phylogenetically distinct mammalian superorders were used to assess reference bias in the reconstructed ancestral karyotypes and to expand the number of clades with reconstructed genomes. The mammalian ancestor likely had 19 pairs of autosomes, with nine of the smallest chromosomes shared with the common ancestor of all amniotes (three still conserved in extant mammals), demonstrating a striking conservation of synteny for similar to 320My of vertebrate evolution. The numbers and types of chromosome rearrangements were classified for transitions between the ancestral mammalian karyotype, descendent ancestors, and extant species. For example, 94 inversions, 16 fissions, and 14 fusions that occurred over 53 My differentiated the therian from the descendent eutherian ancestor. The highest breakpoint rate was observed between the mammalian and therian ancestors (3.9 breakpoints/My). Reconstructed mammalian ancestor chromosomes were found to have distinct evolutionary histories reflected in their rates and types of rearrangements. The distributions of genes, repetitive elements, topologically associating domains, and actively transcribed regions in multispecies homologous synteny blocks and evolutionary breakpoint regions indicate that purifying selection acted over millions of years of vertebrate evolution to maintain syntenic relationships of developmentally important genes and regulatory landscapes of gene-dense chromosomes.
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| 444. |
- de Ridder, Lissy, et al.
(författare)
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Malignancy and Mortality in Pediatric Patients with Inflammatory Bowel Disease : A Multinational Study from the Porto Pediatric IBD Group
- 2014
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Ingår i: Inflammatory Bowel Diseases. - 1078-0998 .- 1536-4844. ; 20:2, s. 291-300
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Tidskriftsartikel (refereegranskat)abstract
- Background: The combination of the severity of pediatric-onset inflammatory bowel disease (IBD) phenotypes and the need for intense medical treatment may increase the risk of malignancy and mortality, but evidence regarding the extent of the problem is scarce. Therefore, the Porto Pediatric IBD working group of ESPGHAN conducted a multinational-based survey of cancer and mortality in pediatric IBD. Methods: A survey among pediatric gastroenterologists of 20 European countries and Israel on cancer and/or mortality in the pediatric patient population with IBD was undertaken. One representative from each country repeatedly contacted all pediatric gastroenterologists from each country for reporting retrospectively cancer and/or mortality of pediatric patients with IBD after IBD onset, during 2006-2011. Results: We identified 18 cases of cancers and/or 31 deaths in 44 children (26 males) who were diagnosed with IBD (ulcerative colitis, n = 21) at a median age of 10.0 years (inter quartile range, 3.0-14.0). Causes of mortality were infectious (n = 14), cancer (n = 5), uncontrolled disease activity of IBD (n = 4), procedure-related (n = 3), other non-IBD related diseases (n = 3), and unknown (n = 2). The most common malignancies were hematopoietic tumors (n = 11), of which 3 were hepatosplenic T-cell lymphoma and 3 Ebstein-Barr virus-associated lymphomas. Conclusions: Cancer and mortality in pediatric IBD are rare, but cumulative rates are not insignificant. Mortality is primarily related to infections, particularly in patients with 2 or more immunosuppressive agents, followed by cancer and uncontrolled disease. At least 6 lymphomas were likely treatment-associated by virtue of their phenotype.
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| 445. |
- Dennison, M. J., et al.
(författare)
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Biosensors for environmental monitoring
- 1995
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Ingår i: Biotechnology Advances. - : Elsevier. - 0734-9750 .- 1873-1899. ; 13:1, s. 1-12
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Forskningsöversikt (refereegranskat)abstract
- Increasing environmental legislation which controls the release and the levels of certain chemicals in the environment has created a need for reliable monitoring of these substances in air, soil and especially water. Conventional analytical techniques, although highly precise, suffer from the disadvantages of high cost, the need for trained personnel and the fact that they are mostly laboratory bound. Biosensors because of their specificity, fast response times, low cost, portability, ease of use and a continuous real time signal, can present distinct advantages in certain cases. Their biological base makes them ideal for toxicological measurements which are suited for health and safety applications. Over the last 3–4 years there has been an increase in the number of publications concerning biosensors for environmental monitoring, especially in the field of pesticide measurements.
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| 446. |
- Dey, Prasenjit, et al.
(författare)
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Estrogen Receptor beta 2 Induces Hypoxia Signature of Gene Expression by Stabilizing HIF-1 alpha in Prostate Cancer
- 2015
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 10:5
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Tidskriftsartikel (refereegranskat)abstract
- The estrogen receptor (ER) beta variant ER beta 2 is expressed in aggressive castration-resistant prostate cancer and has been shown to correlate with decreased overall survival. Genome-wide expression analysis after ER beta 2 expression in prostate cancer cells revealed that hypoxia was an overrepresented theme. Here we show that ER beta 2 interacts with and stabilizes HIF-1 alpha protein in normoxia, thereby inducing a hypoxic gene expression signature. HIF-1 alpha is known to stimulate metastasis by increasing expression of Twist1 and increasing vascularization by directly activating VEGF expression. We found that ER beta 2 interacts with HIF-1 alpha and piggybacks to the HIF-1 alpha response element present on the proximal Twist1 and VEGF promoters. These findings suggest that at least part of the oncogenic effects of ER beta 2 is mediated by HIF-1 alpha and that targeting of this ER beta 2 -HIF-1 alpha interaction may be a strategy to treat prostate cancer.
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| 447. |
- Deyhle, Richard T, et al.
(författare)
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Maintenance of near normal bone mass and architecture in lethally irradiated female mice following adoptive transfer with as few as 750 purified hematopoietic stem cells
- 2019
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Ingår i: Radiation Research. - 0033-7587. ; 5, s. 413-427
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Tidskriftsartikel (refereegranskat)abstract
- Total-body irradiation (TBI) followed by transfer of bone marrow cells from donors is routinely performed in immunology research and can be used to manipulate differentiation and/or function of bone cells. However, exposure to high-dose radiation can result in irreversible osteopenia, and transfer of heterogeneous cell populations can complicate interpretation of results. The goal of this research was to establish an approach for reconstituting bone marrow using small numbers of purified donor-derived hematopoietic stem cells (HSCs) without negatively affecting bone metabolism. Gamma-irradiated (9 Gy) WBB6F1 mice were engrafted with bone marrow cells (5 × 106 cells) or purified HSCs (3,000 cells) obtained from GFP transgenic mice. In vivo analysis and in vitro differentiation assays performed two months later established that both methods were effective in reconstituting the hematopoietic compartment with donor-derived cells. We confirmed these findings by engrafting C57Bl/6 (B6) mice with bone marrow cells or purified HSCs from CD45.1 B6 congenic mice. We next performed adoptive transfer of purified HSCs (750 cells) into WBB6F1 and radiosensitive KitW/W-v mice and evaluated the skeleton two months later. Minimal differences were observed between controls and WBB6F1-engrafted mice that received fractionated doses of 2 × 5 Gy. Kitw/wv mice lost weight and became osteopenic after 2 × 5 Gy irradiations but these abnormalities were negligible after 5 Gy irradiation. Importantly, adoptive transfer of wild-type cells into Kitw/wv mice restored normal Kit expression in bone marrow. Together, these findings provide strong evidence for efficient engraftment with purified HSCs after lethal TBI with minimal collateral damage to bone. This approach will be useful for investigating mechanisms by which hematopoietic lineage cells regulate bone metabolism.
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| 448. |
- Di Trani, Justin M., et al.
(författare)
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Structure of the bc1–cbb3 respiratory supercomplex from Pseudomonas aeruginosa
- 2023
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - 0027-8424 .- 1091-6490. ; 120:40
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Tidskriftsartikel (refereegranskat)abstract
- Energy conversion by electron transport chains occurs through the sequential transfer of electrons between protein complexes and intermediate electron carriers, creating the proton motive force that enables ATP synthesis and membrane transport. These protein complexes can also form higher order assemblies known as respiratory supercomplexes (SCs). The electron transport chain of the opportunistic pathogen Pseudomonas aeruginosa is closely linked with its ability to invade host tissue, tolerate harsh conditions, and resist antibiotics but is poorly characterized. Here, we determine the structure of a P. aeruginosa SC that forms between the quinol:cytochrome c oxidoreductase (cytochrome bc1) and one of the organism’s terminal oxidases, cytochrome cbb3, which is found only in some bacteria. Remarkably, the SC structure also includes two intermediate electron carriers: a diheme cytochrome c4 and a single heme cytochrome c5. Together, these proteins allow electron transfer from ubiquinol in cytochrome bc1 to oxygen in cytochrome cbb3. We also present evidence that different isoforms of cytochrome cbb3 can participate in formation of this SC without changing the overall SC architecture. Incorporating these different subunit isoforms into the SC would allow the bacterium to adapt to different environmental conditions. Bioinformatic analysis focusing on structural motifs in the SC suggests that cytochrome bc1–cbb3 SCs also exist in other bacterial pathogens.
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| 449. |
- Dussel, Veronica, et al.
(författare)
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Looking beyond where children die : Determinants and effects of planning a child's location of death.
- 2009
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Ingår i: Journal of Pain and Symptom Management. - : Elsevier BV. - 0885-3924 .- 1873-6513. ; 37:1, s. 33-43
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Tidskriftsartikel (refereegranskat)abstract
- While dying at home may be the choice of many, where people die may be less important than argued. We examined factors associated with parental planning of a child's location of death (LOD) and its effects on patterns of care and parent's experience. In a cross-sectional study of 140 parents who lost a child to cancer at one of two tertiary-level U.S. pediatric hospitals, 88 (63%) planned the child's LOD and 97% accomplished their plan. After adjusting for disease and family characteristics, families whose primary oncologist clearly explained treatment options during the child's end of life and who had home care involved were more likely to plan LOD. Planning LOD was associated with more home deaths (72% vs. 8% among those who did not plan, P<0.001) and fewer hospital admissions (54% vs. 98%, P<0.001). Parents who planned were more likely to feel very prepared for the child's end of life (33% vs. 12%, P=0.007) and very comfortable with LOD (84% vs. 40%, P<0.001), and less likely to have preferred a different LOD (2% vs. 46%, P<0.001). Among the 73 nonhome deaths, planning was associated with more deaths occurring in the ward than in the intensive care unit or other hospital (92% vs. 33%, P<0.001), and fewer children being intubated (21% vs. 48%, P=0.029). Comprehensive physician communication and home care involvement increase the likelihood of planning a child's LOD. Opportunity to plan LOD is associated with outcomes consistent with high-quality palliative care, even among nonhome deaths, and thus may represent a more relevant outcome than actual LOD.
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| 450. |
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