| 1. |
- Nam, Kwangho, et al.
(författare)
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Magnesium induced structural reorganization in the active site of adenylate kinase
- 2024
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Ingår i: Science Advances. - : American Association for the Advancement of Science (AAAS). - 2375-2548. ; 10:32
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Tidskriftsartikel (refereegranskat)abstract
- Phosphoryl transfer is a fundamental reaction in cellular signaling and metabolism that requires Mg2+ as an essential cofactor. While the primary function of Mg2+ is electrostatic activation of substrates, such as ATP, the full spectrum of catalytic mechanisms exerted by Mg2+ is not known. In this study, we integrate structural biology methods, molecular dynamic (MD) simulations, phylogeny, and enzymology assays to provide molecular insights into Mg2+-dependent structural reorganization in the active site of the metabolic enzyme adenylate kinase. Our results demonstrate that Mg2+ induces a conformational rearrangement of the substrates (ATP and ADP), resulting in a 30° adjustment of the angle essential for reversible phosphoryl transfer, thereby optimizing it for catalysis. MD simulations revealed transitions between conformational substates that link the fluctuation of the angle to large-scale enzyme dynamics. The findings contribute detailed insight into Mg2+ activation of enzymes and may be relevant for reversible and irreversible phosphoryl transfer reactions.
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| 2. |
- Bäcklund, Nils, et al.
(författare)
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Salivary cortisol and cortisone in diagnosis of Cushing's syndrome - a comparison of six different analytical methods
- 2023
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Ingår i: Clinical Chemistry and Laboratory Medicine. - : Walter de Gruyter. - 1434-6621 .- 1437-4331. ; 61:10, s. 1780-1791
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: Salivary cortisol and cortisone at late night and after dexamethasone suppression test (DST) are increasingly used for screening of Cushing's syndrome (CS). We aimed to establish reference intervals for salivary cortisol and cortisone with three liquid chromatography-tandem mass spectrometry (LC-MS/MS) techniques and for salivary cortisol with three immunoassays (IAs), and evaluate their diagnostic accuracy for CS.Methods: Salivary samples at 08:00 h, 23:00 h and 08:00 h after a 1-mg DST were collected from a reference population (n=155) and patients with CS (n=22). Sample aliquots were analyzed by three LC-MS/MS and three IA methods. After establishing reference intervals, the upper reference limit (URL) for each method was used to calculate sensitivity and specificity for CS. Diagnostic accuracy was evaluated by comparing ROC curves.Results: URLs for salivary cortisol at 23:00 h were similar for the LC-MS/MS methods (3.4-3.9 nmol/L), but varied between IAs: Roche (5.8 nmol/L), Salimetrics (4.3 nmol/L), Cisbio (21.6 nmol/L). Corresponding URLs after DST were 0.7-1.0, and 2.4, 4.0 and 5.4 nmol/L, respectively. Salivary cortisone URLs were 13.5-16.6 nmol/L at 23:00 h and 3.0-3.5 nmol/L at 08:00 h after DST. All methods had ROC AUCs =0.96.Conclusions: We present robust reference intervals for salivary cortisol and cortisone at 08:00 h, 23:00 h and 08:00 h after DST for several clinically used methods. The similarities between LC-MS/MS methods allows for direct comparison of absolute values. Diagnostic accuracy for CS was high for all salivary cortisol and cortisone LC-MS/MS methods and salivary cortisol IAs evaluated.
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| 3. |
- Eriksson, Elisabeth, 1971-
(författare)
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Constructing clarity : Swedish teachers’ and students’ shared concern in feedback interaction in primary school classrooms
- 2023
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Ingår i: Education 3-13. - : Routledge; Taylor & Francis. - 0300-4279 .- 1475-7575. ; 51:1, s. 13-25
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Tidskriftsartikel (refereegranskat)abstract
- Feedback is dependent on how it is interpreted and used. The present study aimed to expplore Swedish primary-school teachers' and students' shared concerns regarding classroom feedback interaction. 13 teachers and 23 students (7–9 years old) were interviewed. A grounded theory design was employed for coding and analysis. According to the findings, teachers' and students' mutual main concern was to construct clarity regarding what the other communicated. Both strived to construct clarity concerning conditions that htey had to adapt to, from aspects as trustworthiness and understanding. The study contributes with an illustration of the relational aspect of classroom feedback in primary school.
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| 4. |
- Hainzl, Tobias, et al.
(författare)
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Structural insights into CodY activation and DNA recognition
- 2023
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Ingår i: Nucleic Acids Research. - : Oxford University Press. - 0305-1048 .- 1362-4962. ; 51:14, s. 7631-7648
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Tidskriftsartikel (refereegranskat)abstract
- Virulence factors enable pathogenic bacteria to infect host cells, establish infection, and contribute to disease progressions. In Gram-positive pathogens such as Staphylococcus aureus (Sa) and Enterococcus faecalis (Ef), the pleiotropic transcription factor CodY plays a key role in integrating metabolism and virulence factor expression. However, to date, the structural mechanisms of CodY activation and DNA recognition are not understood. Here, we report the crystal structures of CodY from Sa and Ef in their ligand-free form and their ligand-bound form complexed with DNA. Binding of the ligands - branched chain amino acids and GTP - induces conformational changes in the form of helical shifts that propagate to the homodimer interface and reorient the linker helices and DNA binding domains. DNA binding is mediated by a non-canonical recognition mechanism dictated by DNA shape readout. Furthermore, two CodY dimers bind to two overlapping binding sites in a highly cooperative manner facilitated by cross-dimer interactions and minor groove deformation. Our structural and biochemical data explain how CodY can bind a wide range of substrates, a hallmark of many pleiotropic transcription factors. These data contribute to a better understanding of the mechanisms underlying virulence activation in important human pathogens.
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| 5. |
- Imamovic, Marcus, et al.
(författare)
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Confounding effects of liquorice, hydrocortisone, and blood contamination on salivary cortisol but not cortisone
- 2023
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Ingår i: Endocrine Connections. - : BIOSCIENTIFICA LTD. - 2049-3614. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To determine the effects of liquorice consumption, topical hydro cortisone, and blood contamination on salivary cortisol and cortisone concentrations. Design and methods: Thirty healthy volunteers were randomized to a low, medium, or high dose of liquorice. Late-night saliva samples were collected using a Salivette (R) collection device at baseline, during 1 week of daily liquorice consumption, and during 4 weeks washout. Saliva sampling was also performed before and after the application of topical hydrocortisone on the skin. Furthermore, in a subgroup (n = 16), saliva and venous blood were collected from each individual and mixed to achieve graded blood contamination in saliva. Salivary cortisol and cortisone were a nalyzed with liquid chromatography-tandem mass spectrometry. Results: Significant increases in salivary cortisol concentrations were observed during medium- (+49%) and high-dose (+97%) liquorice intake, which returned to baseline 4 days after liquorice withdrawal. Topical hydrocortisone on fingers holding the collection swab increased salivary cortisol concentrations >1000-fold with concomitant pronounced elevation of the cortisol:cortisone ratio. Salivary cortisol in creased significantly after contamination with blood >= 0.5%. Visual examination could safely detect these samples. Salivary cortisone concentrations were unaffected by liquorice consumption and blood contamination, and only marginally affected by topical hydrocortisone. Conclusion: Liquorice, topical hydrocortisone, and blood contamination may all cause elevated salivary cortisol concentrations. Improved sampling instructions and visual examination of the sample may minimize these risks. Salivary cortisone is essentially unaffected by the different preanalytical confounders and may be used as a first-line screening test for Cushings syndrome.
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| 6. |
- Tischlik, Sonja, et al.
(författare)
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Insights into Enzymatic Catalysis from Binding and Hydrolysis of Diadenosine Tetraphosphate by E. coli Adenylate Kinase
- 2023
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Ingår i: Biochemistry. - : American Chemical Society (ACS). - 0006-2960 .- 1520-4995. ; 62:15, s. 2238-2243
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Tidskriftsartikel (refereegranskat)abstract
- Adenylate kinases play a crucial role in cellular energy homeostasis through the interconversion of ATP, AMP, and ADP in all living organisms. Here, we explore how adenylate kinase (AdK) from Escherichia coli interacts with diadenosine tetraphosphate (AP4A), a putative alarmone associated with transcriptional regulation, stress, and DNA damage response. From a combination of EPR and NMR spectroscopy together with X-ray crystallography, we found that AdK interacts with AP4A with two distinct modes that occur on disparate time scales. First, AdK dynamically interconverts between open and closed states with equal weights in the presence of AP4A. On a much slower time scale, AdK hydrolyses AP4A, and we suggest that the dynamically accessed substrate-bound open AdK conformation enables this hydrolytic activity. The partitioning of the enzyme into open and closed states is discussed in relation to a recently proposed linkage between active site dynamics and collective conformational dynamics.
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| 7. |
- Tükenmez, Hasan, 1987-, et al.
(författare)
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A highly substituted ring-fused 2-pyridone compound targeting PrfA and the efflux regulator BrtA in listeria monocytogenes
- 2023
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Ingår i: mBio. - : American Society for Microbiology. - 2161-2129 .- 2150-7511. ; 14:3
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Tidskriftsartikel (refereegranskat)abstract
- Listeria monocytogenes is a facultative Gram-positive bacterium that causes listeriosis, a severe foodborne disease. We previously discovered that ring-fused 2-pyridone compounds can decrease virulence factor expression in Listeria by binding and inactivating the PrfA virulence activator. In this study, we tested PS900, a highly substituted 2-pyridone that was recently discovered to be bactericidal to other Gram-positive pathogenic bacteria, such as Staphylococcus aureus and Enterococcus faecalis. We show that PS900 can interact with PrfA and reduce the expression of virulence factors. Unlike previous ring-fused 2-pyridones shown to inactivate PrfA, PS900 had an additional antibacterial activity and was found to potentiate sensitivity toward cholic acid. Two PS900-tolerant mutants able to grow in the presence of PS900 carried mutations in the brtA gene, encoding the BrtA repressor. In wild-type (WT) bacteria, cholic acid binds and inactivates BrtA, thereby alleviating the expression of the multidrug transporter MdrT. Interestingly, we found that PS900 also binds to BrtA and that this interaction causes BrtA to dissociate from its binding site in front of the mdrT gene. In addition, we observed that PS900 potentiated the effect of different osmolytes. We suggest that the increased potency of cholic acid and osmolytes to kill bacteria in the presence of PS900 is due to the ability of the latter to inhibit general efflux, through a yet-unknown mechanism. Our data indicate that thiazolino 2-pyridones constitute an attractive scaffold when designing new types of antibacterial agents.IMPORTANCE: Bacteria resistant to one or several antibiotics are a very large problem, threatening not only treatment of infections but also surgery and cancer treatments. Thus, new types of antibacterial drugs are desperately needed. In this work, we show that a new generation of substituted ring-fused 2-pyridones not only inhibit Listeria monocytogenes virulence gene expression, presumably by inactivating the PrfA virulence regulator, but also potentiate the bactericidal effects of cholic acid and different osmolytes. We identified a multidrug repressor as a second target of 2-pyridones. The repressor–2-pyridone interaction displaces the repressor from DNA, thus increasing the expression of a multidrug transporter. In addition, our data suggest that the new class of ring-fused 2-pyridones are efficient efflux inhibitors, possibly explaining why the simultaneous addition of 2-pyridones together with cholic acid or osmolytes is detrimental for the bacterium. This work proves conclusively that 2-pyridones constitute a promising scaffold to build on for future antibacterial drug design.
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| 8. |
- Wiberg, Erik, et al.
(författare)
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A validation study of cT-categories in the Swedish national urinary bladder cancer register - Norrland University Hospital
- 2023
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Ingår i: Journal of Personalized Medicine. - : MDPI. - 2075-4426. ; 13:7
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: In Sweden, all patients with urinary bladder cancer (UBC) are recorded in the Swedish National Register for Urinary Bladder Cancer (SNRUBC). The purpose of this study was to validate the registered clinical tumour categories (cT-categories) in the SNRUBC for Norrland University Hospital, Sweden, from 2009 to 2020, inclusive.METHODS: The medical records of all 295 patients who underwent radical cystectomy for the treatment of UBC were reviewed retrospectively. Possible factors impacting the cT-categories were identified. To optimise cT-classification, computed tomography urography of all patients with suspected tumour-associated hydronephrosis (TAH) or suspected tumour in bladder diverticulum (TIBD) were retrospectively reviewed by a radiologist. Discrepancy was tested with a logistic regression model.RESULTS: cT-categories differed in 87 cases (29.5%). Adjusted logistic regression analysis found TIBD and TAH as significant predictors for incorrect registration; OR = 7.71 (p < 0.001), and OR = 17.7, (p < 0.001), respectively. In total, 48 patients (68.6%) with TAH and 12 patients (52.2%) with TIBD showed discrepancy regarding the cT-category. Incorrect registration was mostly observed during the years 2009-2012.CONCLUSION: The study revealed substantial incorrect registration of cT-categories in SNRUBC. A major part of the misclassifications was related to TAH and TIBD. Registration of these variables in the SNRUBC might be considered to improve correct cT-classification.
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| 9. |
- Eriksson, Elisabeth, 1971-, et al.
(författare)
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"You must learn something during a lesson" : how primary students construct meaning from teacher feedback
- 2022
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Ingår i: Educational studies (Dorchester-on-Thames). - : Routledge. - 0305-5698 .- 1465-3400. ; 48:3, s. 323-340
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Tidskriftsartikel (refereegranskat)abstract
- Teacher feedback can be described as a complex interactional pattern between teacher and student. Formative outcomes of assessment are considered to be enhanced when students understand aims and criteria. In order to better understand the processes of teacher feedback and to improve teaching and classroom assessment, there is a need for research on students' perspectives on feedback. The present study aims to conceptualise how primary-school students construct meaning from teacher feedback. The study was based on focus group interviews with 23 students in grades 2 and 3 (7-9 years old). Constructivist grounded theory was used throughout the study. According to the findings, primary-school students conceptualise teacher feedback as communicating a lot of "musts", centred on learning, involving what the students perceived as things they must learn and what they must do in order to learn. These musts concerned both academic learning and behavioural issues, including tensions between different musts.
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| 10. |
- Eriksson, Victoria, et al.
(författare)
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Thromboembolic events during neoadjuvant chemotherapy in muscle invasive bladder cancer – any correlation to the central venous access? : A clinical practice article
- 2022
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Ingår i: F1000 Research. - : F1000 Research. - 2046-1402. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- Patients with muscle invasive bladder cancer have a generally known 5-year overall survival of approximately 58% with neoadjuvant chemotherapy (NAC). During the last decades, addition of Cisplatinum-based NAC in fit patients prior to radical cystectomy (RC), has significantly improved OS, compared to RC only. However, some published studies following NAC addition, describe an intermediate risk increase of thromboembolic events (TEEs). Placement of central venous access (CVA) before NAC has also been suggested as being a potential risk factor for thrombosis. We present a combination of images and cases from the Northern Swedish health region where three patients developed venous TEE after CVA placement for NAC-administration and found that the time until curable RC was prolonged circa one month each, with an addition of one RC cancelled. These are serious events and to our knowledge, there are no current guidelines on prevention of TEE before RC. The aim with this report was to provide examples of these events and conclude that further prospective trials are warranted on prevention and future guidelines regarding venous anticoagulant treatment for TEE that occur pre-RC in NAC-patients.
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