| 1. |
- Laukka, Erika J, 1986-, et al.
(author)
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Olfactory impairment and domain‐specific cognitive decline : A 12‐year population‐based study
- 2023
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In: Alzheimer's & Dementia. - : John Wiley & Sons. - 1552-5260 .- 1552-5279. ; 19:S18
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Journal article (peer-reviewed)abstract
- Background: Olfactory impairment has been associated with both cognitive impairment and dementia and Alzheimer’s disease (AD). This study aimed to investigate the association between olfactory dysfunction (OD) and change trajectories in different cognitive domains in aging. Method: Participants (n = 2473, mean age = 72 years, 61% female) from the population-based Swedish National study on Aging and Care-Kungsholmen (SNAC-K) were repeatedly assessed with tasks measuring episodic memory, semantic memory, verbal fluency, and perceptual speed across 12 years. OD was measured at baseline and participants were categorized as normosmic, hyposmic, or anosmic based on the Sniffin’ Sticks odor identification task. Linear mixed-effects models were used to assess the associations between baseline OD and rates of cognitive decline. Result: OD was related to poorer baseline performance and faster rates of decline during follow-up in all examined domains, as well as in global cognition. Associations were generally more pronounced for anosmia compared to hyposmia. Conclusion: Olfactory impairment is associated with accelerated decline in aging across a wide range of cognitive domains.
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| 2. |
- Baranto, Adad, 1966, et al.
(author)
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Fracture patterns of the adolescent porcine spine: an experimental loading study in bending-compression
- 2005
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In: Spine. - 1528-1159. ; 30:1, s. 75-82
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Journal article (peer-reviewed)abstract
- STUDY DESIGN: To expose functional spinal units from adolescent porcine to mechanical flexion-compression and extension-compression to failure. The biomechanical, radiologic, magnetic resonance imaging, and histologic characteristics are described. OBJECTIVES: The aim of the present study was to investigate the fracture pattern of functional spinal units from adolescent porcine lumbar spines in in vitro compression loading and bending. SUMMARY OF BACKGROUND DATA: In several studies, it has been shown that the adolescent spine, especially the vertebral growth zones, is vulnerable to trauma. A high frequency of abnormalities affecting the spine has been found among athletes participating in sports with high demands on the back. The etiology of these abnormalities is still a controversial issue. METHODS: Sixteen functional spinal units obtained from eight adolescent male pigs were used. Eight functional spinal units were exposed to flexion-compression and eight functional spinal units to extension-compression loading to failure. They were examined with plain radiography and magnetic resonance imaging before and after the loading. The functional spinal units were finally examined macroscopically and histologically. RESULTS: Fractures/separations were seen in the growth zone anteriorly and more frequently, posteriorly in functional spinal units exposed to flexion-compression. In the extension-compression group, such injuries occurred only anteriorly. Only large fractures could be seen on plain radiographs and on magnetic resonance imaging. Macroscopically, a fracture/separation could be seen in 15 cases and histologically in all 16 cases. The median angle at failure for the flexion group was 17 degrees (range, 12-19) and for the extension group 17 degrees (range, 13-19 degrees). The median ultimate compression load in the flexion-compression group was 1894 N (range, 1607-3138 N) and in the extension-compression group 1801 N (range, 1158-2368 N). CONCLUSIONS: The weakest part of the growing porcine lumbar spine, when compressed into flexion- or extension-compression, was the growth zone. The injury was more extensive in extension loading than during flexion loading. Growth zone injuries of the adolescent spine may go undetected on plain radiographs and magnetic resonance imaging.
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| 3. |
- Baranto, Adad, 1966, et al.
(author)
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Interspinous Process Implants Causes Wear of the Spinous Processes in Patients Treated for Spinal Stenosis—An Experimental Biomechanical Study with Comparison to Clinical Cases
- 2016
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In: Open Journal of Orthopedics. - : Scientific Research Publishing, Inc.. - 2164-3008 .- 2164-3016. ; :6, s. 201-210
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Journal article (peer-reviewed)abstract
- There are few biomechanical studies on Interspinous Process Implants (IPD); however none investigate the amount of wear on spinous processes. Therefore the objective of the present study was to investigate the effect of repetitive loading of the IPD Aperius on the spinous processes in a biomechanical porcine model. For comparison, three patients treated surgically with the same device have been followed for one to two years clinically and with image analyses (X-rays, MRI, CT-scans). Four lumbar spines from 6 months old porcine were divided into seven segments, which received IPD. The segments were exposed to 20,000 cyclical loads. Afterwards the deformation (wear) of the segments was registered. The wear of the spinous processes was measured in mm on a following CT-scan. Additionally, the wear of the ex-vivo was compared to that of the spinous processes investigated by CT-scans or X-ray in three patients treated surgically with the same interspinous implant. The mean maximal deformation of porcine specimens was 1.79 mm (SD 0.25) with the largest deformation occurring in the first quarter of the loading (<5000 cycles). The mean wear of the spinous processes after loading was 6.57 mm. A similar level of wear (mean 12.7 mm) of the spinous processes was detected in the patients. The Aperius IPD creates significant wear on the spinous processes in an experimental biomechanical study. Similar wear of the spinous pro-
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| 4. |
- Baranto, Adad, 1966, et al.
(author)
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Vertebral fractures and separations of endplates after traumatic loading of adolescent porcine spines with experimentally-induced disc degeneration
- 2005
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In: Clin Biomech (Bristol, Avon). - : Elsevier BV. - 0268-0033. ; 20:10, s. 1046-54
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Journal article (peer-reviewed)abstract
- BACKGROUND: Abnormalities of the intervertebral discs have been found in a high frequency among young elite athletes. Several studies have also reported that the adolescent spine, especially the vertebral growth zones, is vulnerable to trauma. However, there is incomplete knowledge regarding the injury mechanism of the growing spine. In this study, the injury patterns of the adolescent porcine spine with disc degeneration were examined. METHODS: Twenty-four male pigs were used. A degenerative disc was created by drilling a hole through the cranial endplate of a lumbar vertebra into the disc. Two months later the animals were sacrificed and the degenerative functional spinal units (segments) were harvested. The segments were divided into three groups and exposed to axial compression, flexion compression or extension compression to failure. The load and angle at failure were measured for each group. The segments were examined with magnetic resonance imaging and plain radiography before and after the loading and finally examined macroscopically and histologically. FINDINGS: The degenerated segments required considerably more compressive load to failure than non-degenerated segments. Creating a flexion injury required significantly more load than an extension injury. Fractures and/or separations of the endplates from the vertebral bodies were seen at the margins of the endplates and in the growth zone. Only severe separations and fractures could be seen on plain radiography and magnetic resonance imaging. INTERPRETATION: The weakest part of the adolescent porcine lumbar spine with experimentally-induced degeneration, when loaded in axial compression, flexion compression or extension compression, was the growth zone, and, to a lesser extent, the endplate. Degenerated discs seem to withstand higher mechanical loads than non-degenerated discs, probably due to altered stress distribution.
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| 5. |
- Ekström, Karin M., 1959, et al.
(author)
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Stärk varumärket - släpp in konsumenten i fabriken
- 2008
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In: Marknadsorientering - Myter och möjligheter. - : Liber. - 9789147088928 ; , s. 205-222
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Book chapter (other academic/artistic)abstract
- Varumärken utvecklas inte bara av producenter som äger varumärken utan konsumenter är i hög grad delaktiga. Marknadsförare behöver bli mer medvetna om hur konsumenter bidrar till att skapa innehåll och mening i ett varumärke. Det gamla synsättet att separera produktion och konsumtion, producenter och konsumenter som härrör från industrialiseringen gäller inte i dagens postmoderna globala marknad, som präglas av transparens och deltagande snarare än slutenhet och passivitet. Att bygga och utveckla varumärken är en kontinuerligt pågående process. Köpare och säljare möts på nya platser och varumärken skapas i nätverk som består av företag, konsumenter, media, reklamskapare etc. Genom att ta del av dessa aktörers olika berättelser kan man få en större förståelse för hur varumärken utvecklas. Två exempel på varumärkesbyggande tas upp i kapitlet. Det ena visar på hur konsumenter som medproducenter bidrar till att göra glas till konst. Det andra visar på hur det inom sjukvården sker en transformation från vård till hälsa, bl a genom de aktiviteter som konsumenten bidrar med. Ett framgångsrikt sätt i framtidens varumärkesbyggande kan vara att öppna upp produktionen och bjuda in konsumenten.
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| 6. |
- Ekström, Lars, 1959, et al.
(author)
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A model for evaluation of the electric activity and oxygenation in the erector spinae muscle during isometric loading adapted for spine patients
- 2020
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In: Journal of Orthopaedic Surgery and Research. - : Springer Science and Business Media LLC. - 1749-799X. ; 15:1
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Journal article (peer-reviewed)abstract
- Background Simultaneous measurement of electromyography (EMG) and local muscle oxygenation is proposed in an isometric loading model adjusted for patients that have undergone spinal surgery. Methods Twelve patients with degenerative lumbar spinal stenosis (DLSS) were included. They were subjected to a test protocol before and after surgery. The protocol consisted of two parts, a dynamic and an isometric Ito loading with a time frame of 60 s and accompanying rest of 120 s. The Ito test was repeated three times. EMG was measured bilaterally at the L4 level and L2 and was recorded using surface electrodes and collected (Biopac Systems Inc.). EMG signal was expressed as RMS and median frequency (MF). Muscle tissue oxygen saturation (MrSO(2)) was monitored using a near-infrared spectroscopy (NIRS) device (INVOS (R) 5100C Oxymeter). Two NIRS sensors were positioned bilaterally at the L4 level. The intensity of the leg and back pain and perceived exertion before, during, and after the test was evaluated with a visual analogue scale (VAS) and Borg RPE-scale, respectively. Results All patients were able to perform and complete the test protocol pre- and postoperatively. A consistency of lower median and range values was noted in the sensors of EMG1 (15.3 mu V, range 4.5-30.7 mu V) and EMG2 (13.6 mu V, range 4.0-46.5 mu V) that were positioned lateral to NIRS sensors at L4 compared with EMG3 (18.9 mu V, range 6.5-50.0 mu V) and EMG4 (20.4 mu V, range 7.5-49.0 mu V) at L2. Right and left side of the erector spinae exhibited a similar electrical activity behaviour over time during Ito test (60 s). Regional MrSO(2) decreased over time during loading and returned to the baseline level during recovery on both left and right side. Both low back and leg pain was significantly reduced postoperatively. Conclusion Simultaneous measurement of surface EMG and NIRS seems to be a promising tool for objective assessment of paraspinal muscle function in terms of muscular activity and local muscle oxygenation changes in response to isometric trunk extension in patients that have undergone laminectomy for spinal stenosis.
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| 7. |
- Ekström, Lars, 1959, et al.
(author)
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In vivo porcine intradiscal pressure as a function of external loading
- 2004
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In: J Spinal Disord Tech. - 1536-0652. ; 17:4, s. 312-6
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Journal article (peer-reviewed)abstract
- BACKGROUND: Spinal loading during daily activity as it relates to the ability of the intervertebral disc to sustain its integrity has been a major issue in spinal research. The purpose of this investigation was to establish the relationship between the intervertebral disc pressure in the nucleus and the load applied to the motion segment in an in vivo porcine model. METHODS: Nine domestic pigs were used in this study. A miniaturized servohydraulic testing machine was affixed to the lumbar spine via four intrapedicular screws, which were inserted bilaterally into the L2 and L3 vertebrae. A pressure needle was inserted through the lateral part of the L2-L3 disc annulus and into the nucleus pulposus. Force, deformation, and intradiscal pressure data were collected during a loading scheme that consisted of applying a set of constant loads in increasing order, that is, 50, 100, 150, 200, and 250 N. Each load was applied for 30 seconds followed by 30-second restitution. RESULTS: Intradiscal nucleus pressure was found to correlate to the applied load in all cases. Linear regression analyses resulted in the following equation: intradiscal pressure (MPa) = 0.08 + 1.25E(-3)(load, N), r(2) = 0.81, n = 8. Intradiscal pressure was also highly linearly dependent on the stress. The intrinsic intradiscal pressure was found to be 81 +/- 5 kPa. The results also indicated that the pressure within the disc exhibited a creep behavior. CONCLUSION: In conclusion, pressure in the nucleus of the porcine intervertebral disc was linearly related to the applied load and stress.
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| 8. |
- Ekström, Lars, 1959, et al.
(author)
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Intervertebral disc response to cyclic loading--an animal model.
- 1996
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In: Proceedings of the Institution of Mechanical Engineers. Part H, Journal of engineering in medicine. - 0954-4119. ; 210:4, s. 249-58
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Journal article (peer-reviewed)abstract
- The viscoelastic response of a lumbar motion segment loaded in cyclic compression was studied in an in vivo porcine model (N = 7). Using surgical techniques, a miniaturized servohydraulic exciter was attached to the L2-L3 motion segment via pedicle fixation. A dynamic loading scheme was implemented, which consisted of one hour of sinusoidal vibration at 5 Hz, 50 N peak load, followed by one hour of restitution at zero load and one hour of sinusoidal vibration at 5 Hz, 100 N peak load. The force and displacement responses of the motion segment were sampled at 25 Hz. The experimental data were used for evaluating the parameters of two viscoelastic models: a standard linear solid model (three-parameter) and a linear Burger's fluid model (four-parameter). In this study, the creep behaviour under sinusoidal vibration at 5 Hz closely resembled the creep behaviour under static loading observed in previous studies. Expanding the three-parameter solid model into a four-parameter fluid model made it possible to separate out a progressive linear displacement term. This deformation was not fully recovered during restitution and is therefore an indication of a specific effect caused by the cyclic loading. High variability was observed in the parameters determined from the 50 N experimental data, particularly for the elastic modulus E1. However, at the 100 N load level, significant differences between the models were found. Both models accurately predicted the creep response under the first 800 s of 100 N loading, as displayed by mean absolute errors for the calculated deformation data from the experimental data of 1.26 and 0.97 percent for the solid and fluid models respectively. The linear Burger's fluid model, however, yielded superior predictions particularly for the initial elastic response.
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| 9. |
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| 10. |
- Holm, Sten, 1948, et al.
(author)
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Experimental disc degeneration due to endplate injury
- 2004
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In: J Spinal Disord Tech. - 1536-0652. ; 17:1, s. 64-71
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Journal article (peer-reviewed)abstract
- The aim of this study was to create an experimental model of disc degeneration that closely mimicked human disc degeneration. In six domestic pigs, an L4 cranial endplate perforation into the nucleus pulposus was made. Three months postoperatively, compressive testing was performed on the L2-L4 motion segments, and intradiscal pressure was measured in the intervening discs. Histochemical and morphologic examinations were made on the excised degenerated and adjacent discs. A significant reduction in water content was observed in the outer anterior annulus of the degenerated disc. In the nucleus, the proteoglycan content was significantly reduced, as well as the cellularity, although not significantly. The nucleus lost its gel-like structure and was discolored, and there was delamination of annular layers. Intradiscal pressure in the nucleus was significantly lower in the degenerated disc. In conclusion, experimental degeneration of the intervertebral disc induced by endplate penetration resembled human disc degeneration, as exemplified by biochemical and structural changes.
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