| 1. |
- Fernström, Maria, et al.
(författare)
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Effects of acute and chronic exercise on mitochondrial uncoupling in human skeletal muscle
- 2004
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Ingår i: Journal of Physiology. - 0022-3751 .- 1469-7793. ; 554:3, s. 755-763
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Tidskriftsartikel (refereegranskat)abstract
- Mitochondrial proteins such as uncoupling protein 3 (UCP3) and adenine nucleotide translocase (ANT) may mediate back-leakage of protons and serve as uncouplers of oxidative phosphorylation. We hypothesized that UCP3 and ANT increase after prolonged exercise and/or endurance training, resulting in increased uncoupled respiration (UCR). Subjects were investigated with muscle biopsies before and after acute exercise (75 min of cycling at 70% of ) or 6 weeks endurance training. Mitochondria were isolated and respiration measured in the absence (UCR or state 4) and presence of ADP (coupled respiration or state 3). Protein expression of UCP3 and ANT was measured with Western blotting. After endurance training , citrate synthase activity (CS), state 3 respiration and ANT increased by 24, 47, 40 and 95%, respectively (all P< 0.05), whereas UCP3 remained unchanged. When expressed per unit of CS (a marker of mitochondrial volume) UCP3 and UCR decreased by 54% and 18%(P < 0.05). CS increased by 43% after acute exercise and remained elevated after 3 h of recovery (P < 0.05), whereas the other muscle parameters remained unchanged. An intriguing finding was that acute exercise reversibly enhanced the capacity of mitochondria to accumulate Ca2+(P < 0.05) before opening of permeability transition pores. In conclusion, UCP3 protein and UCR decrease after endurance training when related to mitochondrial volume. These changes may prevent excessive basal thermogenesis. Acute exercise enhances mitochondrial resistance to Ca2+ overload but does not influence UCR or protein expression of UCP3 and ANT. The increased Ca2+ resistance may prevent mitochondrial degradation and the mechanism needs to be further explored.
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| 2. |
- Fitzgerald, John, 1979, et al.
(författare)
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Including moorings in the assessment of a generic offshore wave energy converter: A frequency domain approach
- 2008
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Ingår i: Marine Structures. - : Elsevier BV. - 0951-8339. ; 21:1, s. 23-46
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Tidskriftsartikel (refereegranskat)abstract
- A method to include the influence of mooring cables in the frequency domain analysis of wave energy converters is presented. In brief the method consists of:(i) A non-linear time domain solution of the mooring line in isolation and at an appropriate equilibrium condition. This is done by enforcing a sinusoidal displacement at the mooring attachment point in each translational degree of freedom. This is repeated at a number of frequencies.(ii) The amplitude and phase of the resulting force is recorded, allowing the equivalent linear resistive and reactive contribution of the mooring line to be estimated separately. Using results at a number of frequencies, frequency dependent impedance properties of the mooring cable can be estimated.(iii) Considering the attachment point and orientation of the mooring cables in a suitable equilibrium condition of the device, the contribution of each mooring cable is resolved to the global co-ordinates of the device and added to the frequency domain equation of motion.The method here is applied to a generic wave energy device based on a truncated vertical cylinder of 100 tonne displacement. The results for the unmoored device are compared to the same device with moorings of varying configuration. The results indicate that moorings may have a significant impact on the performance of devices of this scale, both beneficial and detrimental. The introduction of mooring terms can upset device symmetry and introduce significant cross coupling in the overall mechanical impedance of the device. Arrangements where this can benefit as well as detriment performance are studied.
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| 3. |
- Santillo, Alexander F, et al.
(författare)
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Divergent functional connectivity changes associated with white matter hyperintensities
- 2024
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Ingår i: NeuroImage. - 1095-9572. ; 296
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Tidskriftsartikel (refereegranskat)abstract
- Age-related white matter hyperintensities are a common feature and are known to be negatively associated with structural integrity, functional connectivity, and cognitive performance. However, this has yet to be fully understood mechanistically. We analyzed multiple MRI modalities acquired in 465 non-demented individuals from the Swedish BioFINDER study including 334 cognitively normal and 131 participants with mild cognitive impairment. White matter hyperintensities were automatically quantified using fluid-attenuated inversion recovery MRI and parameters from diffusion tensor imaging were estimated in major white matter fibre tracts. We calculated fMRI resting state-derived functional connectivity within and between predefined cortical regions structurally linked by the white matter tracts. How change in functional connectivity is affected by white matter lesions and related to cognition (in the form of executive function and processing speed) was explored. We examined the functional changes using a measure of sample entropy. As expected hyperintensities were associated with disrupted structural white matter integrity and were linked to reduced functional interregional lobar connectivity, which was related to decreased processing speed and executive function. Simultaneously, hyperintensities were also associated with increased intraregional functional connectivity, but only within the frontal lobe. This phenomenon was also associated with reduced cognitive performance. The increased connectivity was linked to increased entropy (reduced predictability and increased complexity) of the involved voxels' blood oxygenation level-dependent signal. Our findings expand our previous understanding of the impact of white matter hyperintensities on cognition by indicating novel mechanisms that may be important beyond this particular type of brain lesions.
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| 4. |
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| 5. |
- Valdimarsson, T, et al.
(författare)
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Three years' follow-up of bone density in adult coeliac disease : Significance of secondary hyperparathyroidism
- 2000
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Ingår i: Scandinavian Journal of Gastroenterology. - 0036-5521 .- 1502-7708. ; 35:3, s. 274-280
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Tidskriftsartikel (refereegranskat)abstract
- Background: The mechanisms of disturbances in bone mineral density (BMD) in coeliac disease are not completely understood. The aim of this prospective study was to investigate the possible significance of secondary hyperparathyroidism (SHPT) with regard to BMD in patients with untreated coeliac disease. Methods: One hundred and five adult patients with untreated coeliac disease were examined for BMD and serum parathyroid hormone (PTH) concentration. BMD in the hip, lumbar spine, and forearm were examined up to 3 years after the introduction of a gluten-free diet. Results: SHPT was found in 27% (28 of 105) of the patients. In patients with SHPT serum levels of 25- hydroxy-vitamin D were lower and those of alkaline phosphatase higher than in patients with normal PTH, but ionized serum calcium did not differ between the two groups. BMD was more severely reduced in patients with SHPT. Although the BMD increment was more rapid in patients with than in those without SPTH, only in the latter group did mean BMD became normal after 1-3 years on a gluten-free diet (GFD). After 3 years on a GFD more than half of the patients with initial SHPT still had low BMD in both the hip and the forearm. Furthermore, in patients with SHPT the intestinal mucosa more often remained atrophic at the 1-year follow-up, despite good compliance with the diet. Conclusions: Low BMD in patients with untreated coeliac disease is often associated with SHPT. After 3 years on a GFD the BMD remains low only in patients with initial SHPT. We therefore suggest that PTH should be measured when the diagnosis of coeliac disease is made, as an indicator of more serious intestinal disorder and complicating bone disease.
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| 6. |
- Abbasi, R., et al.
(författare)
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IceCube Search for Neutrinos Coincident with Gravitational Wave Events from LIGO/Virgo Run O3
- 2023
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 944:1
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Tidskriftsartikel (refereegranskat)abstract
- Using data from the IceCube Neutrino Observatory, we searched for high-energy neutrino emission from the gravitational-wave events detected by the advanced LIGO and Virgo detectors during their third observing run. We did a low-latency follow-up on the public candidate events released during the detectors' third observing run and an archival search on the 80 confident events reported in the GWTC-2.1 and GWTC-3 catalogs. An extended search was also conducted for neutrino emission on longer timescales from neutron star containing mergers. Follow-up searches on the candidate optical counterpart of GW190521 were also conducted. We used two methods; an unbinned maximum likelihood analysis and a Bayesian analysis using astrophysical priors, both of which were previously used to search for high-energy neutrino emission from gravitational-wave events. No significant neutrino emission was observed by any analysis, and upper limits were placed on the time-integrated neutrino flux as well as the total isotropic equivalent energy emitted in high-energy neutrinos.
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| 7. |
- Alehagen, Urban, et al.
(författare)
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Supplementation with Selenium and Coenzyme Q10 Reduces Cardiovascular Mortality in Elderly with Low Selenium Status. A Secondary Analysis of a Randomised Clinical Trial
- 2016
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Ingår i: PLOS ONE. - : PUBLIC LIBRARY SCIENCE. - 1932-6203. ; 11:7
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Tidskriftsartikel (refereegranskat)abstract
- Background Selenium is needed by all living cells in order to ensure the optimal function of several enzyme systems. However, the selenium content in the soil in Europe is generally low. Previous reports indicate that a dietary supplement of selenium could reduce cardiovascular disease but mainly in populations in low selenium areas. The objective of this secondary analysis of a previous randomised double-blind placebo-controlled trial from our group was to determine whether the effects on cardiovascular mortality of supplementation with a fixed dose of selenium and coenzyme Q10 combined during a four-year intervention were dependent on the basal level of selenium. Methods In 668 healthy elderly individuals from a municipality in Sweden, serum selenium concentration was measured. Of these, 219 individuals received daily supplementation with selenium (200 mu g Se as selenized yeast) and coenzyme Q10 (200 mg) combined for four years. The remaining participants (n = 449) received either placebo (n = 222) or no treatment (n = 227). All cardiovascular mortality was registered. No participant was lost during a median follow-up of 5.2 years. Based on death certificates and autopsy results, all mortality was registered. Findings The mean serum selenium concentration among participants at baseline was low, 67.1 mu g/L. Based on the distribution of selenium concentration at baseline, the supplemented group was divided into three groups; amp;lt;65 mu g/L, 65-85 mu g/L, and amp;gt;85 mu g/L (45 and 90 percentiles) and the remaining participants were distributed accordingly. Among the non-treated participants, lower cardiovascular mortality was found in the high selenium group as compared with the low selenium group (13.0% vs. 24.1%; P = 0.04). In the group with the lowest selenium basal concentration, those receiving placebo or no supplementation had a mortality of 24.1%, while mortality was 12.1% in the group receiving the active substance, which was an absolute risk reduction of 12%. In the middle selenium concentration group a mortality of 14.0% in the non-treated group, and 6.0% in the actively treated group could be demonstrated; thus, there was an absolute risk reduction of 8.0%. In the group with a serum concentration of amp;gt;85 mu g/L, a cardiovascular mortality of 17.5% in the non-treated group, and 13.0% in the actively treated group was observed. No significant risk reduction by supplementation could thus be found in this group. Conclusions In this evaluation of healthy elderly Swedish municipality members, two important results could be reported. Firstly, a low mean serum selenium concentration, 67 mu g/L, was found among the participants, and the cardiovascular mortality was higher in the subgroup with the lower selenium concentrations amp;lt; 65 mu g/L in comparison with those having a selenium concentration amp;gt; 85 mu g/L. Secondly, supplementation was cardio-protective in those with a low selenium concentration, amp;lt;= 85 at inclusion. In those with serum seleniumamp;gt; 85 mu g/L and no apparent deficiency, there was no effect of supplementation. This is a small study, but it presents interesting data, and more research on the impact of lower selenium intake than recommended is therefore warranted.
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| 8. |
- Andrusivova, Zaneta
(författare)
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Development and application of spatial transcriptomics methods
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Transcriptomics is one of the pivotal fields in molecular biology, enabling comprehensive analysis of gene expression patterns. Recent advancements in the biotechnology field have transformed the transcriptomics research, providing insights into the complexity of cellular processes in a greater detail. However, conventional transcriptomics methods such as bulk RNA sequencing or single-cell RNA sequencing rely on tissue dissociation and therefore lack spatial information, which limits our understanding of gene expression patterns within the tissue structures. The development of spatially resolved transcriptomics methods has revolutionized the study of transcriptomes, enabling analysis of gene expression patterns in the spatial context. The wide range of available transcriptomics technologies offer various levels of resolution and throughput, and combination of multiple techniques can be beneficial for studying biological systems and gain deeper understanding of their molecular processes. In this thesis, particular emphasis is given to the Visium spatial gene expression technology, which has gain widespread popularity in the research community over the recent years. In the article I, we expand the application of the Visium platform to fresh-frozen samples of lower RNA quality or otherwise challenging characteristics. To achieve this, we introduce specific modifications to the commercially available protocol and test its effectiveness across different tissue types of varying RNA quality, including pediatric brain tumors, human small intestine, and mouse bone and cartilage. By conducting comparative analysis, we demonstrate that the new protocol outperforms the standard Visium protocol when working with samples of moderate and lower RNA quality.Article II introduces a novel method that enhances the resolution of the Visium gene expression method through tissue expansion. We showcase the implementation of this new protocol on two regions of mouse brain, olfactory bulb and hippocampus. We demonstrate the ability of this approach to study smaller tissue structures that were previously beyond the resolution capabilities of the Visium platform.In the article III and IV, we demonstrate the practical application of the Visium approach and its combination with other methodologies in the field of developmental biology. We show how utilizing spatial transcriptomics methods help elucidate the spatial organization of cell types and cell states during organogenesis in the developing human spinal cord (article III) and developing lung tissue (article IV). By deploying single-cell RNA sequencing and spatial methods, we described the spatiotemporal gene expression profiles of various cell types as well as shared and unique events occurring during the spinal cord development in humans and rodents (article III). Applying this multimodal approach to lung tissue (article IV) allowed us to characterize novel cell states emerging during lung development and provided valuable insights into the structural organization of developing lungs. These studies highlight the findings and observations that can be gained by combining spatially resolved transcriptomics with other laboratory techniques to shed light on the spatial dynamics of cellular processes during organ development.
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| 9. |
- Andruškienė, Jurgita, et al.
(författare)
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Psychosocial work experiences related to health : a study of Lithuanian hospital employees
- 2015
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Ingår i: Work. - 1051-9815 .- 1875-9270. ; 53:3, s. 669-677
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Research in the area of workplace health promotion from a salutogenic perspective is lacking in Eastern Europe.OBJECTIVE: To evaluate the relationship between psychosocial work environment and health from a salutogenic perspective among Lithuanian hospital workers.METHODS: Using a cross-sectional design a questionnaire was distributed to staff in a large hospital in Lithuania. Out of 811 employees, 714 completed the survey: 151 physicians, 449 nurses and 114 other staff members (e.g., psychologists, technicians, therapists). A response rate of 88.0% was achieved. The Work Experience Measurement Scale (WEMS) and the Salutogenic Health Indicator Scale (SHIS) were linguistically adapted and used for the first time in a Lithuanian context. Logistic and multiple linear regression models were used for the analyses.RESULTS: Supportive working conditions, positive internal work experiences and time experience contributed the most to good health, defined as a high SHIS index. Having an executive post was significantly related to good work experiences, i.e. a high WEMS score, while being at the age of 40-54 years was associated with a low WEMS score. Physicians had the highest score on supportive working conditions; while nurses had the lowest scores on autonomy.CONCLUSIONS: A salutogenic approach enables an organisation to identify how to improve working conditions for the employees by focusing on possibilities and resources. Individual activities for workplace health promotion among different work groups seem necessary.
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| 10. |
- Athanassiadis, Tuija, 1971-, et al.
(författare)
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Identification of c-Fos immunoreactive brainstem neurons activated during fictive mastication in the rabbit
- 2005
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Ingår i: Experimental Brain Research. - : Springer Science and Business Media LLC. - 0014-4819 .- 1432-1106. ; 165:4, s. 478-489
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Tidskriftsartikel (refereegranskat)abstract
- In the present study we used the expression of the c-Fos-like protein as a "functional marker" to map populations of brainstem neurons involved in the generation of mastication. Experiments were conducted on urethane-anesthetized and paralyzed rabbits. In five animals (experimental group), rhythmical bouts of fictive masticatory-like motoneuron activity (cumulative duration 60-130 min) were induced by electrical stimulation of the left cortical "masticatory area" and recorded from the right digastric motoneuron pool. A control group of five animals (non-masticatory) were treated in the same way as the experimental animals with regard to surgical procedures, anesthesia, paralysis, and survival time. To detect the c-Fos-like protein, the animals were perfused, and the brainstems were cryosectioned and processed immunocytochemically. In the experimental group, the number of c-Fos-like immunoreactive neurons increased significantly in several brainstem areas. In rostral and lateral areas, increments occurred bilaterally in the borderzones surrounding the trigeminal motor nucleus (Regio h); the rostrodorsomedial half of the trigeminal main sensory nucleus; subnucleus oralis-gamma of the spinal trigeminal tract; nuclei reticularis parvocellularis pars alpha and nucleus reticularis pontis caudalis (RPc) pars alpha. Further caudally-enhanced labeling occurred bilaterally in nucleus reticularis parvocellularis and nucleus reticularis gigantocellularis (Rgc) including its pars-alpha. Our results provide a detailed anatomical record of neuronal populations that are correlated with the generation of the masticatory motor behavior.
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