Change search
Refine search result
1 - 24 of 24
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Kruse, Johan
    et al.
    Luleå University of Technology, Department of Health Sciences, Medical Science.
    Lehto, Niklas
    Luleå University of Technology, Department of Health Sciences, Medical Science.
    Riklund, Katrine
    Department of Radiation Sciences, Diagnostic Radiology, Umeå University.
    Tegner, Yelverton
    Luleå University of Technology, Department of Health Sciences, Medical Science.
    Engström, Åsa
    Luleå University of Technology, Department of Health Sciences, Nursing Care.
    Scrutinized with inadequate control and support Interns' experiences communicating with and writing referrals to hospital radiology departments: a qualitative study2016In: Radiography, ISSN 1078-8174, E-ISSN 1532-2831, Vol. 22, no 4, p. 313-318Article in journal (Refereed)
    Abstract [en]

    IntroductionInterns' experiences communicating with and writing referrals to hospital radiology departments are important for patient safety, image quality, and decision-making in the diagnostic process. Understanding roles within the department and in the diagnostic process is important for communication. This study aimed to describe interns' experiences communicating with and writing referrals to their hospital's radiology department.MethodA qualitative study design was used. Data was collected from focus discussions with ten interns in three focus groups in Northern Sweden during 2012. The data were subjected to qualitative content analysis.ResultsOne theme, “a feeling of being scrutinized and lacking control”, was identified in the final categories. The interns experienced that the radiology department placed high demands on them and desired more diagnostic skills training, resources and feedback. The interns suggested the following improvements: enhanced dialogue and feedback, improved education, handy guidelines, and practice writing referrals.ConclusionInterns need more feedback from, and dialogue with, members of the Department of Radiology. They also need more knowledge of referral guidelines, appropriateness criteria and more practice to develop their knowledge and skill for writing referrals. They describe feelings of inadequate support and feel scrutinized in demanding work conditions and need more collaboration. They also need more time and more control of radiology outcomes, and they are eager to learn.

  • 2.
    Lehto, Niklas
    Luleå University of Technology, Department of Health Sciences, Medical Science.
    Aktivitet: Vad har kroppens fysik med fysik att göra?2013Conference paper (Other (popular science, discussion, etc.))
  • 3.
    Lehto, Niklas
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Dislocations in silicon1998Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The topic of this thesis is theoretical studies of the electrical and structural properties in the elemental semiconductor silicon. Because of the numerous and powerful applications of semiconductors, e.g., rectifiers, transistors, solar cells and lasers, they have been the focus of huge amounts of research. Electronic devices necessitate use of almost pure semiconductor materials, normally in the form of a single crystal. In this crystal an accurately measured amount, usually extremely small, of a foreign dopant has been included to control its electrical properties. The properties of a device may be distributed by unwanted defects. Dislocations are examples of defects that degrade the performance of an electronic device, and they may even cause breakdown. This is due to the influence of dislocations on density, mobility and, most importantly, lifetime of the electrical carriers in the material. In newer semiconductor materials, such as III-V compounds, Si-Ge alloys, heterostructures and strained layers, dislocations cause problems. Dislocations in silicon are amenable more than most other solids to many different characterisation techniques and theoretical approaches. Therefore, a thorough understanding of dislocations in silicon is valuable, and an important milestone in the longer journey towards a comprehensive description of dislocations in all semiconductors. This thesis presents theoretical calculations focused on dislocations and some dislocation-related defects in silicon. Firstly, the electronic states of intrinsic stacking faults bounded by dislocations are investigated. Such stacking faults are one constituent part of commonly occurring extended dislocations in silicon. Secondly, the electronic and atomic structure of vacancies interacting with dislocations is investigated. This is important since vacancies are gettered by dislocations. Finally dislocation- dislocation interaction and its effects on the core structure of the so- called 90* partial dislocation are investigated. In order to study dislocation-dislocation interactions, a new and self-constitent method to apply periodic boundary conditions is introduced.

  • 4.
    Lehto, Niklas
    Luleå University of Technology, Department of Health Sciences, Medical Science.
    Effects of age on marathon finishing time among male amateur runners in Stockholm marathon 1979-20142016In: Journal of Sport and Health Science, ISSN 2095-2546, E-ISSN 2213-2961, Vol. 5, no 3, p. 349-354Article in journal (Refereed)
    Abstract [en]

    PurposeThe purpose of the present study was to investigate the age-related changes in the endurance performance among male amateur marathon runners.MethodsSubjects were taken from the 36 Stockholm Marathons heldfrom 1979 through 2014, and age and finishing time were analyzed for a total of 312,342male runners.ResultsThe relation was found to be a second-order polynomial, t = a + bx + cx2, which models 99.7% of the variation in the average running time t as a function of age x. The model shows that the marathon performance of the average runner improves up to age 34.3 ± 2.6 years, thereafter, the performance starts to decline. Aquantification of the age’s influence on running time shows that it accounts for 4.5% of the total variance seen in the performance data.ConclusionThese outcomes indicate that the effect of age on performance in endurance running events is clearly measurable, quantifiable and possible to describe. At the same time the findings indicate that other factors, such as training, affect the performance more. A comparison with the elite showed peak performance at the same age, but the rates of change in performance with age, improvement as well as degradation, was found to be higher among the elite.

  • 5.
    Lehto, Niklas
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Electronic structure of intrinsic stacking faults in silicon1995Licentiate thesis, comprehensive summary (Other academic)
  • 6.
    Lehto, Niklas
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Shallow electron states of bounded intrinsic stacking faults in silicon1997In: Physical Review B Condensed Matter, ISSN 0163-1829, E-ISSN 1095-3795, Vol. 55, no 23, p. 15601-7Article in journal (Refereed)
    Abstract [en]

    The electronic structure of bounded intrinsic stacking faults in silicon is studied. Especially the influence of the stacking fault width on the electronic states in the band gap is investigated. The extended defect studied comprises an intrinsic stacking fault with two reconstructed 90° partials as boundaries. The atomic structure is determined by different valence force fields. These are the Keating potential, the bond-charge model, and an anharmonic version of the bond-charge model. The electronic structure is calculated by linear combinations of atomic orbitals. Ten Gaussian-type atomic orbitals of s, p, and d-type are used, and up to fourth nearest neighbor interactions are taken into account. The levels in the band gap are evaluated by the recursion method for nonorthogonal basis functions, and by a continued fraction representation of the local density of states

  • 7.
    Lehto, Niklas
    Luleå University of Technology, Department of Health Sciences, Medical Science.
    Varför spendera tid på interaktion?: En undersökning av studenters användning av ett asynkront diskussionsforum2014In: NU 2014: Umeå 8-10 oktober : abstracts, Umeå: Umeå universitet. Pedagogiska institutionen , 2014, p. 54-Conference paper (Refereed)
  • 8. Lehto, Niklas
    et al.
    Heggie, Malcolm
    Modelling of dislocations in c-Si1999In: Properties of crystalline silicon: Properties of crystalline silicon, London: Institution of Electrical Engineers (IEE), 1999, p. 357-378Chapter in book (Refereed)
  • 9.
    Lehto, Niklas
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Marklund, Sune
    Yong-Liang, Wang
    Institute of Semiconductors, Chinese Academy of Sciences.
    Electron states of a stacking fault ribbon in silicon1994In: Solid State Communications, ISSN 0038-1098, E-ISSN 1879-2766, Vol. 92, no 12, p. 987-989Article in journal (Refereed)
    Abstract [en]

    The electronic structure of a bounded intrinsic stacking fault in silicon is calculated. The method used is an LCAO-scheme (Linear Combinations of Atomic Orbitals) taking ten atomic orbitals of s-, p-, and d-type into account. The levels in the band gap are extracted using Lanczos' algorithm and a continued fraction representation of the local density of states. We find occupied states located up to 0.3 eV above the valence band maximum (Eυ). This significantly differs from the result obtained for the ideal infinite fault for which the interface state is located at Eυ+0.1 eV

  • 10.
    Lehto, Niklas
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Öberg, Sven
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mathematical Science.
    Effects of dislocation interactions: application to the period-doubled core of the 90° partial in silicon1998In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 80, no 25, p. 5568-71Article in journal (Refereed)
    Abstract [en]

    The elastic strain field of a dislocation is highly affected by nearby dislocations. The effects of dislocation-dislocation interactions on elastic energy and core structure are analyzed using a new and self-consistent method to apply periodic boundary conditions on unit cells containing dislocations. Local density functional theory on hydrogen terminated clusters is used to gauge the effects of long-range elastic fields on the core structure of the 90° partial in silicon. It is shown that the single and double period structures of this core are very close in energy, and that the structure adopted probably depends on the environment in which the dislocation is located

  • 11.
    Lehto, Niklas
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Öberg, Sven
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mathematical Science.
    Interaction of vacancies with partial dislocations in silicon1997In: Physical Review B Condensed Matter, ISSN 0163-1829, E-ISSN 1095-3795, Vol. 56, no 20, p. R12706-R12709Article in journal (Refereed)
    Abstract [en]

    The interaction of vacancies with 30° and 90° partial dislocations in silicon is examined. In particular, the structures and binding energies are calculated using hydrogen-terminated clusters and local density-functional theory. Moreover the electronic structure is determined using supercells containing dislocation dipoles. Vacancies are found to have binding energies of approximately 2.0 eV and 0.9 eV to 90° and 30° partials, respectively. The elastic strain field of the partials makes the fourfold vacancy reconstruct, which essentially clears the fundamental gap

  • 12.
    Leijon-Sundqvist, Katarina
    et al.
    Luleå University of Technology, Department of Health Sciences, Medical Science.
    Lehto, Niklas
    Luleå University of Technology, Department of Health Sciences, Medical Science.
    Juntti, Ulla
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics. Performance in Cold AB, Luleå.
    Karp, Kjell
    Heart Centre, Clinical Physiology, Department of Surgical and Perioperative Sciences, Umeå University.
    Andersson, Staffan
    Luleå University of Technology, Department of Health Sciences, Medical Science.
    Tegner, Yelverton
    Luleå University of Technology, Department of Health Sciences, Medical Science.
    Thermal response after cold-water provocation of hands in healthy young men2015In: Thermology International, ISSN 1560-604X, Vol. 25, no 2, p. 48-53Article in journal (Refereed)
    Abstract [en]

    The thermal response in hands provoked by cold water was investigated with infrared thermography. In 26 healthy young men, the response of hand skin temperature to cold water provocation was measured twice on consecutive days. An infrared thermographic camera was used and data were processed in real time. The software divides each hand into 18 predefined regions of interest (ROI). The average temperature in each ROI was stored every 10th second. Baseline hand skin temperature was recorded for two minutes. The bare hands were then immersed for 30 seconds in water at 10°C × 0.5°C and carefully dried. Thereafter, the cooled and final hand skin temperature was measured. The baseline showed a higher average temperature of 0.3°C on day 2 and the 95% limits of agreement (LOA) were - 5.2-5.8, the cooled average temperatures showed no significant difference between the two days (LOA: - 4.8-4.6) and the average final hand skin temperature was 0.8°C higher on day 2 (LOA: - 5.2-6.4). In conclusion, there was variability between the two measurements, small differences in the temperature response to the reaction to cold-water provocation - probably due to Day 1 stress factor.

  • 13.
    Leijon-Sundqvist, Katarina
    et al.
    Luleå University of Technology, Department of Health Sciences, Medical Science.
    Lehto, Niklas
    Luleå University of Technology, Department of Health Sciences, Medical Science.
    Juntti, Ulla
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Karp, Kjell
    Umeå university.
    Tegner, Yelverton
    Luleå University of Technology, Department of Health Sciences, Medical Science.
    Cold-water provocation of hands: An evaluation of different provocations2015In: Thermology International, ISSN 1560-604X, Vol. 25, no 3, p. 122-123Article in journal (Refereed)
  • 14.
    Leijon-Sundqvist, Katarina
    et al.
    Luleå University of Technology, Department of Health Sciences, Medical Science.
    Lehto, Niklas
    Luleå University of Technology, Department of Health Sciences, Medical Science.
    Juntti, Ulla
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Linné, Anders
    Karp, Kjell
    Andersson, Staffan
    Tegner, Yelverton
    Luleå University of Technology, Department of Health Sciences, Medical Science.
    Thermal response after cold-water provocation of hands of healthy young men: A test-retest investigation2014Conference paper (Other academic)
  • 15.
    Leijon-Sundqvist, Katarina
    et al.
    Luleå University of Technology, Department of Health Sciences, Medical Science.
    Tegner, Yelverton
    Luleå University of Technology, Department of Health Sciences, Medical Science.
    Juntti, Ulla
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics. Performance in Cold AB, Luleå.
    Karp, Kjell
    Division of Clinical Physiology, Department of Surgical and Perioperative Sciences, Umeå University.
    Lehto, Niklas
    Luleå University of Technology, Department of Health Sciences, Medical Science.
    Hand skin temperature: are there warm and cold rewarming patterns after cold stress test?2016In: Thermology International, ISSN 1560-604X, Vol. 26, no 3, p. 81-87Article in journal (Refereed)
    Abstract [en]

    In 116 thermographic measurements of 66 healthy male participants, 44 of whom were measured at least twice, hand skin temperature distributions before and after a cold stress test (CST) were examined to identify any typical characteristics of hand skin rewarming. On each hand, measurements from 18 regions of interest recorded every 10 s were used to calculate the surface average temperature. Temperatures at baseline (Tb), directly after cooling (Tc), and after 15 min of rewarming (Tf) were used for comparison and the averages of each finger, palm, and hand were analyzed. Using fits of normal distribution for the measured data, final hand skin temperatures were divided into two groups, A and B, with a calculated boundary at 25.4 °C. Digital analyses of all thermograms were performed to describe the process, and each group's rewarming patterns were observed. Group A was considered to demonstrate warm rewarming, since the whole hands reached a Tf approximately equal to the Tb. By contrast, Group B demonstrated cold rewarming and had whole hand Tf less than Tb. The predictive value of Tc was lower than that of Tb in Group A, whereas the opposite occurred in Group B. Altogether, the findings suggest different hand skin temperature rewarming patterns in healthy males.

  • 16.
    Leijon-Sundqvist, Katarina
    et al.
    Luleå University of Technology, Department of Health Sciences, Medical Science.
    Tegner, Yelverton
    Luleå University of Technology, Department of Health Sciences, Medical Science.
    Olsson, F.
    ABB, Norrköping.
    Karp, Kjell
    Heart Centre, Clinical Physiology, Department of Surgical and Perioperative Sciences, Umeå University.
    Lehto, Niklas
    Luleå University of Technology, Department of Health Sciences, Medical Science.
    Relation between dorsal and palmar hand skin temperatures during a cold stress test2017In: Journal of Thermal Biology, ISSN 0306-4565, E-ISSN 1879-0992, Vol. 66, p. 87-92Article in journal (Refereed)
    Abstract [en]

    Hand skin temperature measurements have previously been performed on either dorsal or palmar sides and it is possible to find arguments for the advantage of both locations. Therefore, the aim of this study was to use dynamic infrared (IR) imaging to examine the relationship between dorsal and palmar hand skin temperature. The palmar and dorsal hand skin temperature before and after a cold stress test was measured with IR thermography in 112 healthy participants. Calculation of surface average temperature was made from nine regions of interest on each hand's dorsal and palmar side. Temperature values were recorded at baseline, directly after immersion of hands in vinyl gloves for one minute in water at 20 °C ± 0.5 °C (gloves removed), and after eight minutes rewarming. Results showed that: a) the skin temperatures on the dorsal and palmar sides of the hand are strongly correlated; b) the correlation is stronger on the fingers than on the carpometacarpal (CMC) area; c) the palmar side of the CMC area is warmer than the dorsal side, but this is reversed in the fingers so that the nail bed is warmer than the finger pad; and d) the temperature difference ∆T∆T between the dorsal and palmar sides of the fingers is independent of the skin temperature, though ∆T∆T on the CMC area of the hand is temperature dependent. Such differences can be important in detailed investigations of thermal phenomena in the hand. In conclusion, results showed a strong correlation between the dorsal and palmar temperatures. If both sides cannot be measured, the purpose of the investigation should determine which side of the hand should be measured.

  • 17.
    Lestander, Örjan
    et al.
    Luleå University of Technology, Department of Health Sciences, Medical Science.
    Lehto, Niklas
    Luleå University of Technology, Department of Health Sciences, Medical Science.
    Vad kan studenterna lära sig genom att titta i backspegeln?2014In: NU 2014: Umeå 8-10 oktober : abstracts, Umeå: Umeå universitet. Pedagogiska institutionen , 2014, p. 96-Conference paper (Refereed)
  • 18.
    Lestander, Örjan
    et al.
    Luleå University of Technology, Department of Health Sciences, Medical Science.
    Lehto, Niklas
    Luleå University of Technology, Department of Health Sciences, Medical Science.
    Engström, Åsa
    Luleå University of Technology, Department of Health Sciences, Nursing Care.
    Nursing students' perceptions of learning after High Fidelity simulation: Effects of a Three-step Post-Simulation Reflection Model2016In: Nurse Education Today, ISSN 0260-6917, E-ISSN 1532-2793, Vol. 40, p. 219-224Article in journal (Refereed)
    Abstract [en]

    High-fidelity simulation (HFS) has become a bridge between theoretical knowledge and practical skills. A safe and realistic environment is commonly used in nursing education to improve cognitive, affective and psychomotor abilities. Debriefing following a simulation experience provides opportunities for students to analyse and begin to reflect upon their decisions, actions and results. The nursing literature highlights the need to promote the concept of reflective practice and to assist students in reflection, and research indicates the need to refine and develop debriefing strategies, which is the focus of the current paper.

  • 19.
    Mouzon, Johanne
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Maitre, A.
    Laboratoire Science des Procédés Céramiques et Traitements de Surface, UMR CNRS 6638, UFR Sciences et Techniques, 123 Avenue Albert Thomas, F-87060 Limoges Cedex.
    Frisk, Lars
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Lehto, Niklas
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Odén, Magnus
    Fabrication of transparent yttria by HIP and the glass-encapsulation method2009In: Journal of the European Ceramic Society, ISSN 0955-2219, E-ISSN 1873-619X, Vol. 29, no 2, p. 311-316Article in journal (Refereed)
    Abstract [en]

    This method consists of a combination of vacuum sintering at 1600 °C followed by hot isostatic pressing (HIP) at 1500 °C of a highly agglomerated commercial powder. The use of evacuated glass capsules to perform HIP treatment allowed samples that showed open porosity after vacuum sintering to be sintered to transparency. The sintering response of the investigated powder was studied by careful microstructural observations using scanning electron microscopy and optical microscopy both in reflection and transmission. The successful key of this method was to keep porosity intergranular during pre-sintering, so that it can be removed subsequently by HIP treatment. It was found that agglomerates of closely packed particles are helpful to reach that purpose, since they densify fully and leave only intergranular porosity. However, performing HIP treatment at 1625 °C was found to result in opaque samples. This was attributed to the diffusion of argon inside the capsule. Contamination at different steps of processing was also investigated by inductively coupled plasma mass spectrometry (ICP-MS).

  • 20.
    Röijezon, Ulrik
    et al.
    Luleå University of Technology, Department of Health Sciences, Health and Rehabilitation.
    Løvoll, Grunde
    Norwegian Institute for Water Research (NIVA), Section for Environmental Data Science .
    Henriksson, Anders
    Department of Sport and Health Sciences, School of Education, Health and Social Sciences, Dalarna University.
    Tonkonogi, Michail
    Department of Sport and Health Sciences, School of Education, Health and Social Sciences, Dalarna University.
    Lehto, Niklas
    Luleå University of Technology, Department of Health Sciences, Medical Science.
    An Initial Study on the Coordination of Rod and Line Hauling Movements in Distance Fly Casting2017In: Annals of Applied Sport Science, ISSN 2476-4981, Vol. 5, no 2, p. 61-72Article in journal (Refereed)
    Abstract [en]

    Background. The double haul is a unique feature of single-handed fly casting and is used in both fly fishing and fly casting competition. The movement behaviour during the double haul has not been investigated in previous research.

    Objectives. Describe the coordination of the rod and line hauling movements during distance fly casting.

    Methods. Elite fly casters performed distance casting with four different fly rod and fly line set-ups used in fly fishing and fly casting competition. Rod and hauling movements were measured with a 3D motion analysis system.

    Results. The rod and line hauling movements were coordinated in an order whereby peak translational speed of the rod occurs prior to the peak speed of the angular rotation of the rod, and the peak speed of the angular rotation of the rod occurs prior to the peak speed of the line haul. This was consistent for all cast sequences, i.e., the back and forward false casts and the delivery cast, and for all four equipment set-ups, i.e., a shooting-head line cast with a relatively stiff fly rod and a long-belly line cast with three different fly rods with different stiffness and action curves. Results also showed differences in movement coordination between cast sequences and rod and line set-ups.

    Conclusion. Among elite casters, single-handed fly casting with double haul is coordinated in an order of events whereby the peak speed occurs first for the translation of the rod, then for the rotation of the rod and finally for the line haul.

  • 21.
    Shahim, Pashtun
    et al.
    Clinical Neurochemistry Laboratory, Institute of Neuroscience and Physiology, Sahlgrenska Academy at University of Gothenburg, Sahlgrenska University Hospita.
    Tegner, Yelverton
    Luleå University of Technology, Department of Health Sciences, Medical Science.
    Gustafsson, Bengt
    Capio Artro Clinic, Stockholm.
    Gren, Magnus
    Clinical Neurochemistry Laboratory, Institute of Neuroscience and Physiology, Sahlgrenska Academy at University of Gothenburg, Sahlgrenska University Hospita.
    Ärlig, Johan
    Clinical Neurochemistry Laboratory, Institute of Neuroscience and Physiology, Sahlgrenska Academy at University of Gothenburg, Sahlgrenska University Hospita.
    Olsson, Martin
    Clinical Neurochemistry Laboratory, Institute of Neuroscience and Physiology, Sahlgrenska Academy at University of Gothenburg, Sahlgrenska University Hospita.
    Lehto, Niklas
    Luleå University of Technology, Department of Health Sciences, Medical Science.
    Engström, Åsa
    Luleå University of Technology, Department of Health Sciences, Nursing Care.
    Höglund, Kina
    Clinical Neurochemistry Laboratory, Institute of Neuroscience and Physiology, Sahlgrenska Academy at University of Gothenburg, Sahlgrenska University Hospita.
    Portelius, Erik
    Clinical Neurochemistry Laboratory, Institute of Neuroscience and Physiology, Sahlgrenska Academy at University of Gothenburg, Sahlgrenska University Hospita.
    Zetterberg, Henrik
    Clinical Neurochemistry Laboratory, Institute of Neuroscience and Physiology, Sahlgrenska Academy at University of Gothenburg, Sahlgrenska University Hospital, Mölndal.
    Blennow, Kaj
    Clinical Neurochemistry Laboratory, Institute of Neuroscience and Physiology, Sahlgrenska Academy at University of Gothenburg, Sahlgrenska University Hospita.
    Neurochemical Aftermath of Repetitive Mild Traumatic Brain Injury2016In: JAMA Neurology, ISSN 2168-6149, E-ISSN 2168-6157, Vol. 73, no 11, p. 1308-1315Article in journal (Refereed)
    Abstract [en]

    Importance:

    Evidence is accumulating that repeated mild traumatic brain injury (mTBI) incidents can lead to persistent, long-term debilitating symptoms and in some cases a progressive neurodegenerative condition referred to as chronic traumatic encephalopathy. However, to our knowledge, there are no objective tools to examine to which degree persistent symptoms after mTBI are caused by neuronal injury.

    Objective:

    To determine whether persistent symptoms after mTBI are associated with brain injury as evaluated by cerebrospinal fluid biochemical markers for axonal damage and other aspects of central nervous system injury.

    Design, Settings, and Participants:

    A multicenter cross-sectional study involving professional Swedish ice hockey players who have had repeated mTBI, had postconcussion symptoms for more than 3 months, and fulfilled the criteria for postconcussion syndrome (PCS) according to the Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition) matched with neurologically healthy control individuals. The participants were enrolled between January 2014 and February 2016. The players were also assessed with Rivermead Post Concussion Symptoms Questionnaire and magnetic resonance imaging.

    Main Outcomes and Measures:

    Neurofilament light protein, total tau, glial fibrillary acidic protein, amyloid β, phosphorylated tau, and neurogranin concentrations in cerebrospinal fluid.

    Results:

    A total of 31 participants (16 men with PCS; median age, 31 years; range, 22-53 years; and 15 control individuals [11 men and 4 women]; median age, 25 years; range, 21-35 years) were assessed. Of 16 players with PCS, 9 had PCS symptoms for more than 1 year, while the remaining 7 returned to play within a year. Neurofilament light proteins were significantly increased in players with PCS for more than 1 year (median, 410 pg/mL; range, 230-1440 pg/mL) compared with players whose PCS resolved within 1 year (median, 210 pg/mL; range, 140-460 pg/mL) as well as control individuals (median 238 pg/mL, range 128-526 pg/mL; P = .04 and P = .02, respectively). Furthermore, neurofilament light protein concentrations correlated with Rivermead Post Concussion Symptoms Questionnaire scores and lifetime concussion events (ρ = 0.58, P = .02 and ρ = 0.52, P = .04, respectively). Overall, players with PCS had significantly lower cerebrospinal fluid amyloid-β levels compared with control individuals (median, 1094 pg/mL; range, 845-1305 pg/mL; P = .05).

    Conclusions and Relevance:

    Increased cerebrospinal fluid neurofilament light proteins and reduced amyloid β were observed in patients with PCS, suggestive of axonal white matter injury and amyloid deposition. Measurement of these biomarkers may be an objective tool to assess the degree of central nervous system injury in individuals with PCS and to distinguish individuals who are at risk of developing chronic traumatic encephalopathy.

  • 22.
    Sundbaum, Johanna
    et al.
    Luleå University of Technology, Department of Health Sciences, Medical Science.
    Back, Johan
    Institutionen för medicinska vetenskaper, Uppsala Universitet.
    Lehto, Niklas
    Luleå University of Technology, Department of Health Sciences, Medical Science.
    Vikman, Irene
    Luleå University of Technology, Department of Health Sciences, Health and Rehab.
    Baecklund, Eva
    Institutionen för medicinska vetenskaper, Uppsala Universitet.
    Kontrollprovtagning vid metotrexatebehandling av RA patienter: Erfarenheter från en reumatologklinik2014Conference paper (Other academic)
  • 23.
    Sundbaum, Johanna
    et al.
    Luleå University of Technology, Department of Health Sciences, Medical Science.
    Berglund, V.
    Uppsala University, Dermatologic Section, Department of Medical Science.
    Back, Johan
    Institutionen för medicinska vetenskaper, Uppsala Universitet.
    Lehto, Niklas
    Luleå University of Technology, Department of Health Sciences, Medical Science.
    Vikman, Irene
    Luleå University of Technology, Department of Health Sciences, Health and Rehab.
    Rollman, O.
    Uppsala University, Dermatologic Section, Department of Medical Science.
    Baecklund, Eva
    Enheten för reumatologi, Institutionen för medicinska vetenskaper, Uppsala universitet, Institutionen för medicinska vetenskaper, Uppsala Universitet.
    Methotrexate in rheumatoid arthritis and psoriasis/psoriatic arthritis: a comparative study of hepatotoxicity2014In: Scandinavian Journal of Rheumatology, ISSN 0300-9742, E-ISSN 1502-7732, Vol. 43, p. 29-Article in journal (Refereed)
  • 24.
    Sundbaum, Johanna
    et al.
    Luleå University of Technology, Department of Health Sciences, Medical Science. Department of Medical Sciences, Rheumatology, Uppsala University, Uppsala, Sweden.
    Eriksson, Niclas
    Department of Medical Sciences, Clinical Pharmacology and Science for Life Laboratory, Uppsala University, Uppsala, Sweden.
    Hallberg, Pär
    Department of Medical Sciences, Clinical Pharmacology and Science for Life Laboratory, Uppsala University, Uppsala, Sweden.
    Lehto, Niklas
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science. Luleå University of Technology, Department of Health Sciences, Medical Science.
    Wadelius, Mia
    Department of Medical Sciences, Clinical Pharmacology and Science for Life Laboratory, Uppsala University, Uppsala, Sweden.
    Baecklund, Eva
    Department of Medical Sciences, Rheumatology, Uppsala University, Uppsala, Sweden.
    Methotrexate treatment in rheumatoid arthritis and elevated liver enzymes: A long‐term follow‐up of predictors, surveillance, and outcome in clinical practice2019In: International Journal of Rheumatic Diseases, E-ISSN 1756-185XArticle in journal (Refereed)
    Abstract [en]

    Aim

    To assess predictors of alanine aminotransferase (ALT) elevation in methotrexate (MTX) treated rheumatoid arthritis (RA) patients, and to describe the monitoring of liver enzymes, including handling and outcome of elevated ALT.

    Methods

    All RA patients starting MTX in January, 2005 to April, 2013 at a rheumatology clinic, (Uppsala University Hospital, Sweden) were identified from electronic medical records. Clinical and laboratory data were obtained from medical records, supplemented by telephone interviews. Predictors for ALT >1.5× over the upper limit of normal (ULN) were identified by multiple regression analysis.

    Results

    The study comprised 213 RA patients starting MTX. During a mean follow‐up of 4.3 years, 6288 ALT tests were performed; 7% of tests with ALT were >ULN. ALT >1.5× ULN was observed in 44 (21%) patients and the strongest predictor was a pre‐treatment elevation of ALT (adjusted odds ratio = 6.8, 95% CI 2.2‐20.5). Recurrent elevations occurred in 70% of patients who continued treatment, and the proportion was similar in those with and without interventions, for example MTX dose reduction (67% vs 73%, P = 0.43). Seven patients (3%) permanently stopped MTX due to ALT elevation, and two were eventually diagnosed with non‐alcoholic fatty liver disease. No patient developed hepatic failure.

    Conclusion

    Only a small number of ALT tests performed during MTX therapy in RA capture an elevation. A pre‐treatment elevation of ALT was the strongest predictor for early and recurrent ALT elevations during therapy. This study supports a more individualized approach to monitoring and handling of ALT elevations during MTX therapy in RA than recommended in current guidelines.

1 - 24 of 24
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf