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| 4. |
- Hellgren, Mikko, 1972-, et al.
(författare)
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Alcohol dehydrogenase 2 is a major hepatic enzyme for human retinol metabolism
- 2007
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Ingår i: Cellular and Molecular Life Sciences (CMLS). - : Springer. - 1420-682X .- 1420-9071. ; 64:4, s. 498-505
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Tidskriftsartikel (refereegranskat)abstract
- The metabolism of all-trans- and 9-cis-retinol/ retinaldehyde has been investigated with focus on the activities of human, mouse and rat alcohol dehydrogenase 2 (ADH2), an intriguing enzyme with apparently different functions in human and rodents. Kinetic constants were determined with an HPLC method and a structural approach was implemented by in silico substrate dockings. For human ADH2, the determined K(m) values ranged from 0.05 to 0.3 microM and k(cat) values from 2.3 to 17.6 min(-1), while the catalytic efficiency for 9-cis-retinol showed the highest value for any substrate. In contrast, poor activities were detected for the rodent enzymes. A mouse ADH2 mutant (ADH2Pro47His) was studied that resembles the human ADH2 setup. This mutation increased the retinoid activity up to 100-fold. The K(m) values of human ADH2 are the lowest among all known human retinol dehydrogenases, which clearly support a role in hepatic retinol oxidation at physiological concentrations.
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| 7. |
- Höög, Johanna L, et al.
(författare)
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Electron tomography reveals a flared morphology on growing microtubule ends
- 2011
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Ingår i: Journal of Cell Science. - : The Company of Biologists. - 0021-9533 .- 1477-9137. ; 124:Pt 5, s. 693-698
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Tidskriftsartikel (refereegranskat)abstract
- Microtubules (MTs) exhibit dynamic instability, alternating between phases of growth and shortening, mostly at their uncapped plus ends. Based on results from cryo-electron microscopy it was proposed that growing MTs display mainly curved sheets and blunt ends; during depolymerisation curled 'ramshorns' predominate. Observations of MTs in mitotic cells have suggested that the situation in vivo differs from that in vitro, but so far, a clear comparison between in vivo and in vitro results has not been possible because MT end structures could not be correlated directly with the dynamic state of that particular MT. Here we combine light microscopy and electron tomography (ET) to show that growing MT plus ends in the fission yeast Schizosaccharomyces pombe display predominantly a flared morphology. This indicates that MT polymerisation in vivo and in vitro can follow different paths.
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| 10. |
- Juhlin, CC, et al.
(författare)
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Perithyroidal Salivary Gland Acinic Cell Carcinoma: Morphological and Molecular Attributes of a Unique Lesion
- 2021
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Ingår i: Head and neck pathology. - : Springer Science and Business Media LLC. - 1936-0568. ; 15:2, s. 628-637
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Tidskriftsartikel (refereegranskat)abstract
- Rarely, salivary gland tumors such as mucoepidermoid carcinoma, mammary analogue secretory carcinoma and mucinous carcinoma arise as primary tumors from ectopic or metaplastic salivary gland tissue adjacent to or within the thyroid gland. We report for the first time a case of primary salivary acinic cell carcinoma (AcCC) adjacent to the thyroid gland in a 71-year-old female patient with Crohns disease and a previous history of malignant melanoma. Following the development of a nodule adjacent to the left thyroid lobe, a fine-needle aspiration biopsy was reported as consistent with a follicular lesion of undetermined significance (Bethesda III). A left-sided hemithyroidectomy was performed. A circumscribed lesion measuring 33 mm was noted adjacent to the thyroid and trapping parathyroid, it was composed of solid nests and glands with microcystic and follicular patterns. The tumor was negative for thyroid, parathyroid and paraganglioma markers, but positive for pan-cytokeratins, CK7, CD10, CD117, androgen receptor and HNF-beta. A metastasis of a thyroid-like renal cell carcinoma was suspected but ruled out, and the patient had no evident lesions on extensive radiology of the urogenital, pulmonary and GI tracts. Based on the morphology, a diagnosis of AcCC was suggested, and confirmed with DOG1 and PAS-diastase staining. Molecular analyses pinpointed a constitutional ASXL1 variant of uncertain significance, but no fusion events. The patient had no radiological or clinical evidence of parotid, submandibular or sublingual tumors postoperatively, and the excised lesion was therefore assumed to be a primary tumor. We here detail the morphological and immunophenotypic profile of this previously undescribed perithyroidal tumor.
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| 11. |
- Kouznetsova, A., et al.
(författare)
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Age-dependent aneuploidy in mammalian oocytes instigated at the second meiotic division
- 2022
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Ingår i: Aging Cell. - : Wiley. - 1474-9718 .- 1474-9726. ; 21:7
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Tidskriftsartikel (refereegranskat)abstract
- Ageing severely affects the chromosome segregation process in human oocytes resulting in aneuploidy, infertility and developmental disorders. A considerable amount of segregation errors in humans are introduced at the second meiotic division. We have here compared the chromosome segregation process in young adult and aged female mice during the second meiotic division. More than half of the oocytes in aged mice displayed chromosome segregation irregularities at anaphase II, resulting in dramatically increased level of aneuploidy in haploid gametes, from 4% in young adult mice to 30% in aged mice. We find that the post-metaphase II process that efficiently corrects aberrant kinetochore-microtubule attachments in oocytes in young adult mice is approximately 10-fold less efficient in aged mice, in particular affecting chromosomes that show small inter-centromere distances at the metaphase II stage in aged mice. Our results reveal that post-metaphase II processes have critical impact on age-dependent aneuploidy in mammalian eggs.
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| 12. |
- Nešić, Nebojša, et al.
(författare)
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Automated segmentation of cell organelles in volume electron microscopy using deep learning
- 2024
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Ingår i: Microscopy Research and Technique. - 1059-910X .- 1097-0029.
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Tidskriftsartikel (refereegranskat)abstract
- Recent advances in computing power triggered the use of artificial intelligence in image analysis in life sciences. To train these algorithms, a large enough set of certified labeled data is required. The trained neural network is then capable of producing accurate instance segmentation results that will then need to be re-assembled into the original dataset: the entire process requires substantial expertise and time to achieve quantifiable results. To speed-up the process, from cell organelle detection to quantification across electron microscopy modalities, we propose a deep-learning based approach for fast automatic outline segmentation (FAMOUS), that involves organelle detection combined with image morphology, and 3D meshing to automatically segment, visualize and quantify cell organelles within volume electron microscopy datasets. From start to finish, FAMOUS provides full segmentation results within a week on previously unseen datasets. FAMOUS was showcased on a HeLa cell dataset acquired using a focused ion beam scanning electron microscope, and on yeast cells acquired by transmission electron tomography. Research Highlights: Introducing a rapid, multimodal machine-learning workflow for the automatic segmentation of 3D cell organelles. Successfully applied to a variety of volume electron microscopy datasets and cell lines. Outperforming manual segmentation methods in time and accuracy. Enabling high-throughput quantitative cell biology.
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| 13. |
- Nyström, Monica E., et al.
(författare)
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Exploring the potential of a multi-level approach to improve capability for continuous organizational improvement and learning in a Swedish healthcare region
- 2018
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Ingår i: BMC Health Serv Res. - : Springer Science and Business Media LLC. - 1472-6963. ; 18
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Tidskriftsartikel (refereegranskat)abstract
- Background: Eldercare and care of people with functional impairments is organized by the municipalities in Sweden. Improving care in these areas is complex, with multiple stakeholders and organizations. Appropriate strategies to develop capability for continuing organizational improvement and learning (COIL) are needed. The purpose of our study was to develop and pilot-test a flexible, multilevel approach for COIL capability building and to identify what it takes to achieve changes in key actors' approaches to COIL. The approach, named "Sustainable Improvement and Development through Strategic and Systematic Approaches" (SIDSSA), was applied through an action-research and action-learning intervention. Methods: The SIDSSA approach was tested in a regional research and development (R&D) unit, and in two municipalities handling care of the elderly and people with functional impairments. Our approach included a multilevel strategy, development loops of five flexible phases, and an action-learning loop. The approach was designed to support systems understanding, strategic focus, methodological practices, and change process knowledge-all of which required double-loop learning. Multiple qualitative methods, i.e., repeated interviews, process diaries, and documents, provided data for conventional content analyses. Results: The new approach was successfully tested on all cases and adopted and sustained by the R&D unit. Participants reported new insights and skills. The development loop facilitated a sense of coherence and control during uncertainty, improved planning and problem analysis, enhanced mapping of context and conditions, and supported problem-solving at both the individual and unit levels. The systems-level view and structured approach helped participants to explain, motivate, and implement change initiatives, especially after working more systematically with mapping, analyses, and goal setting. Conclusions: An easily understood and generalizable model internalized by key organizational actors is an important step before more complex development models can be implemented. SIDSSA facilitated individual and group learning through action-learning and supported systems-level views and structured approaches across multiple organizational levels. Active involvement of diverse organizational functions and levels in the learning process was facilitated. However, the time frame was too short to fully test all aspects of the approach, specifically in reaching beyond the involved managers to front-line staff and patients.
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| 14. |
- Nyström, Monica, et al.
(författare)
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Framtidens välfärdstjänster : Nya arbetssätt för innovativ serviceutveckling inom vård och omsorg
- 2014
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- En växande andel äldre i befolkningen i kombination med en minskande andel arbetskraft ställer allt tuffare krav på utveckling av vård och omsorg. För att klara dessa utmaningar och utveckla framtidens välfärdtjänster krävs nya innovativa arbetssätt. Vi arbetar nu med ett projekt som handlar om verksamhets- och serviceutveckling inom området äldre och vuxna med funktionsnedsättning. Projektet drivs i samarbete med ett tvärvetenskapligt forskarteam från Karolinska institutet, Göteborgs universitet och Luleå tekniska universitet och pågår från november 2009 till och med december 2012.Syftet med projektet är att i regionen Sörmland utveckla och testa arbetssätt som kan stödja innovativ verksamhets- och serviceutveckling inom området äldre och vuxna med funktionsnedsättning. Projektet involverar flera organisatoriska nivåer och huvudmän, inklusive landsting och kommuner. Den teoretiska basen bygger på lärdomar från kvalitetsutveckling, organisatoriskt lärande, innovationsforskning och organisatorisk kreativitet. Upplägget ger förutsättningar för lärande och snabb återkoppling över organisatoriska gränser. Resultaten kan bidra till kunskap om hur olika förutsättningar påverkar lärande, kreativitet och innovationsutveckling inom vård och omsorg, vilket i sin tur underlättar beslut kring strategiska satsningar och ökad kvalitet i vården. Projektet förväntas ge ny kunskap kring organisationers lärandeprocess som kan användas även för andra utvecklingssatsningar.
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| 15. |
- Olsson, Erik J, et al.
(författare)
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Konvergenstanken i Hans Larssons filosofi
- 2024
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Ingår i: Humanisten Hans Larsson : Filosofiska och litterära praktiker för vår tid - Filosofiska och litterära praktiker för vår tid. - 0436-8096. - 9789198520736 - 9789198520729 ; 27, s. 11-42
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 16. |
- Panagaki, Dimitra, et al.
(författare)
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Nuclear envelope budding is a response to cellular stress.
- 2021
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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. - 1091-6490 .- 0027-8424. ; 118:30
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Tidskriftsartikel (refereegranskat)abstract
- Nuclear envelope budding (NEB) is a recently discovered alternative pathway for nucleocytoplasmic communication distinct from the movement of material through the nuclear pore complex. Through quantitative electron microscopy and tomography, we demonstrate how NEB is evolutionarily conserved from early protists to human cells. In the yeast Saccharomyces cerevisiae, NEB events occur with higher frequency during heat shock, upon exposure to arsenite or hydrogen peroxide, and when the proteasome is inhibited. Yeast cells treated with azetidine-2-carboxylic acid, a proline analog that induces protein misfolding, display the most dramatic increase in NEB, suggesting a causal link to protein quality control. This link was further supported by both localization of ubiquitin and Hsp104 to protein aggregates and NEB events, and the evolution of these structures during heat shock. We hypothesize that NEB is part of normal cellular physiology in a vast range of species and that in S. cerevisiae NEB comprises a stress response aiding the transport of protein aggregates across the nuclear envelope.
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| 17. |
- Parigi, Sara M., et al.
(författare)
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Flt3 ligand expands bona fide innate lymphoid cell precursors in vivo
- 2018
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Ingår i: Scientific Reports. - : NATURE PUBLISHING GROUP. - 2045-2322. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- A common helper-like innate lymphoid precursor (CHILP) restricted to the innate lymphoid cells (ILC) lineage has been recently characterized. While specific requirements of transcription factors for CHILPs development has been partially described, their ability to sense cytokines and react to peripheral inflammation remains unaddressed. Here, we found that systemic increase in Flt3L levels correlated with the expansion of Lineage (Lin)(neg)alpha 4 beta 7(+) precursors in the adult murine bone marrow. Expanded Lin(neg)alpha 4 beta 7(+) precursors were bona fide CHILPs as seen by their ability to differentiate into all helper ILCs subsets but cNK in vivo. Interestingly, Flt3L-expanded CHILPs transferred into lymphopenic mice preferentially reconstituted the small intestine. While we did not observe changes in serum Flt3L during DSS-induced colitis in mice or plasma from inflammatory bowel disease (IBD) patients, elevated Flt3L levels were detected in acute malaria patients. Interestingly, while CHILP numbers were stable during the course of DSS-induced colitis, they expanded following increased serum Flt3L levels in malaria-infected mice, hence suggesting a role of the Flt3L-ILC axis in malaria. Collectively, our results indicate that Flt3L expands CHILPs in the bone marrow, which might be associated with specific inflammatory conditions.
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| 19. |
- Zabeo, Davide, 1992, et al.
(författare)
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A lumenal interrupted helix in human sperm tail microtubules
- 2018
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Eukaryotic flagella are complex cellular extensions involved in many human diseases gathered under the term ciliopathies. Currently, detailed insights on flagellar structure come mostly from studies on protists. Here, cryo-electron tomography (cryo-ET) was performed on intact human spermatozoon tails and showed a variable number of microtubules in the singlet region (inside the end-piece). Inside the microtubule plus end, a novel left-handed interrupted helix which extends several micrometers was discovered. This structure was named Tail Axoneme Intra-Lumenal Spiral (TAILS) and binds directly to 11 protofilaments on the internal microtubule wall, in a coaxial fashion with the surrounding microtubule lattice. It leaves a gap over the microtubule seam, which was directly visualized in both singlet and doublet microtubules. We speculate that TAILS may stabilize microtubules, enable rapid swimming or play a role in controlling the swimming direction of spermatozoa.
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| 20. |
- Östberg, Linus J., et al.
(författare)
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Computational analysis of human medium-chain dehydrogenases/ reductases revealing substrate- and coenzyme-binding characteristics
- 2024
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Ingår i: Chemico-Biological Interactions. - : Elsevier. - 0009-2797 .- 1872-7786. ; 390
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Tidskriftsartikel (refereegranskat)abstract
- The medium-chain dehydrogenase/reductase (MDR) superfamily has more than 600,000 members in UniProt as of March 2023. As the family has been growing, the proportion of functionally characterized proteins has been falling behind. The aim of this project was to investigate the binding pockets of nine different MDR protein families based on sequence conservation patterns and three-dimensional structures of members within the respective families. A search and analysis methodology was developed. Using this, a total of 2000 eukaryotic MDR sequences belonging to nine different families were identified. The pairwise sequence identities within each of the families were 80-90 % for the mammalian sequences, like the levels observed for alcohol dehydrogenase, another MDR family. Twenty conserved residues were identified in the coenzyme part of the binding site by matching structural and conservation data of all nine protein families. The conserved residues in the substrate part of the binding pocket varied between the nine MDR families, implying divergent functions for the different families. Studying each family separately made it possible to identify multiple conserved residues that are expected to be important for substrate binding or catalysis of the enzymatic reaction. By combining structural data with the conservation of the amino acid residues in each protein, important residues in the binding pocket were identified for each of the nine MDRs. The obtained results add new positions of interest for the binding and activity of the enzyme family as well as fit well to earlier published data. Three distinct types of binding pockets were identified, containing no, one, or two tyrosine residues.
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| 21. |
- Östberg, Linus J., et al.
(författare)
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Computational studies of human class V alcohol dehydrogenase - the odd sibling
- 2016
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Ingår i: BMC Biochemistry. - : Springer Science and Business Media LLC. - 1471-2091. ; 17
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Tidskriftsartikel (refereegranskat)abstract
- Background: All known attempts to isolate and characterize mammalian class V alcohol dehydrogenase (class V ADH), a member of the large ADH protein family, at the protein level have failed. This indicates that the class V ADH protein is not stable in a non-cellular environment, which is in contrast to all other human ADH enzymes. In this report we present evidence, supported with results from computational analyses performed in combination with earlier in vitro studies, why this ADH behaves in an atypical way. Results: Using a combination of structural calculations and sequence analyses, we were able to identify local structural differences between human class V ADH and other human ADHs, including an elongated beta-strands and a labile a-helix at the subunit interface region of each chain that probably disturb it. Several amino acid residues are strictly conserved in class I-IV, but altered in class V ADH. This includes a for class V ADH unique and conserved Lys51, a position directly involved in the catalytic mechanism in other ADHs, and nine other class V ADH-specific residues. Conclusions: In this study we show that there are pronounced structural changes in class V ADH as compared to other ADH enzymes. Furthermore, there is an evolutionary pressure among the mammalian class V ADHs, which for most proteins indicate that they fulfill a physiological function. We assume that class V ADH is expressed, but unable to form active dimers in a non-cellular environment, and is an atypical mammalian ADH. This is compatible with previous experimental characterization and present structural modelling. It can be considered the odd sibling of the ADH protein family and so far seems to be a pseudoenzyme with another hitherto unknown physiological function.
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