| 1. |
- Hannukainen, J, et al.
(författare)
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In Vivo Measurements of Glucose Uptake in Human Achilles Tendon During Different Exercise Intensities
- 2005
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Ingår i: International Journal of Sports Medicine. - : Georg Thieme Verlag KG. - 0172-4622 .- 1439-3964. ; 26, s. 727-731
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Tidskriftsartikel (refereegranskat)abstract
- Muscular contraction and loading of adjacent tendons has been demonstrated to cause increased blood flow and metabolic activity in the peritendinous region. However, it is poorly known to what extent the human tendon itself takes up glucose during exercise. Thus, the purpose of this study was to measure tendon glucose uptake with increasing exercise intensity and to compare it to muscle glucose uptake at the same intensities. Eight young men were examined on three separate days during which they performed 35 min of cycling at 30, 55 and 75 % of VO2max, respectively. Glucose uptake was measured directly by positron emission tomography (PET) with 2-[ (18)F]fluoro-2-deoxyglucose ([18F]FDG). [18F]FDG was injected after 10 min of exercise that was continued for a further 25 min after the injection. PET scanning of the thigh and Achilles region was performed after the exercise. Glucose uptake of the Achilles tendon (AT) remained unchanged (7.1 +/- 1.5, 6.6 +/- 1.1, and 6.0 +/- 1.1 micromol.kg(-1).min(-1)) with the increasing workload, although the glucose uptake in m. quadriceps femoris simultaneously clearly increased (48 +/- 35, 120 +/- 35, and 152 +/- 74 micromol.kg(-1).min(-1), p < 0.05). In conclusion, the AT takes up glucose during exercise but in significantly smaller amounts than the skeletal muscle does. Furthermore, glucose uptake in the AT is not increased with the increasing exercise intensity. This may be partly explained by the cycle ergometry exercise used in the present study, which probably causes only a little increase in strain to the AT with increasing exercise intensity.
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| 2. |
- Viljanen, E.K., et al.
(författare)
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Degree of conversion and flexural properties of a dendrimer/methyl methacrylate copolymer: Design of experiments and statistical screening
- 2005
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Ingår i: Dental Materials. - : Elsevier BV. - 0109-5641 .- 1879-0097. ; 21:2, s. 172-177
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: The aim of this study was to investigate the effect of photosensitive initiator and activator concentrations on the degree of conversion and flexural properties of an experimental photopolymerized dental copolymer containing dendrimer. Methods: The experimental resin system consisted of a dendrimer with 12 methacrylate groups and methyl methacrylate in a mass ratio of 80:20. The initiator and activator used were camphorquinone and 2-(N,N-dimethylamino)ethyl methacrylate, whose concentrations varied individually from 1 to 4wt%. The degree of conversion was determined with FTIR spectroscopy, and flexural strength and flexural modulus with the three-point bending test. The experiments were designed and analyzed, and the results plotted with Modde 5.0 software. Results: The highest degree of conversion was obtained with 2.5wt% initiator and activator concentrations, the highest flexural strength with 2.5wt% initiator and 1.0wt% activator concentration, and the highest flexural modulus with 1.0wt% initiator and activator concentrations. Significance: The results indicated that the degree of conversion increased, and flexural strength and flexural modulus decreased, with increasing initiator and activator concentrations. The high concentrations of initiator probably inhibited the transmittance of the active wavelengths to the depths of the samples (the inner filter effect), resulting in inhomogeneous conversion and thus decreased mechanical properties. © 2004 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.
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| 3. |
- Viljanen, Johan, et al.
(författare)
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Surface-assisted delivery of fluorescent groups to hGST A1-1 and a lysine mutant
- 2006
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Ingår i: Bioconjugate Chemistry. - : American Chemical Society (ACS). - 1043-1802 .- 1520-4812. ; 17:2, s. 429-437
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Tidskriftsartikel (refereegranskat)abstract
- Human glutathione transferase (hGST) Al-l and a lysine mutant(A216K) can both be rapidly and site-specifically acylated on Y9 and K216, respectively, using a range of thiolesters of glutathione (GS-thiolesters) as modifying reagents. The present investigation was aimed at developing a method with which to deliver a fluorescent acyl group from a solid support under conditions compatible with standard protein purification schemes. A number of fluorescent GS-thiolesters with modified peptide backbones were therefore prepared and tested for reactivity toward hGST Al-l and the A216K mutant. Substitutions at the alpha-NH2 part of the glutathione backbone were not tolerated by the proteins. However, two fluorescent reagents that carry a biotin moiety at the C-terminal part of glutathione were found through MALDI-MS experiments to react in solution with Y9 of the wild-type protein and one reagent with K216 of A216K. The reaction can take place in the presence of glutathione and even in a crude E. coli lysate of cells expressing A216K. Delivery of the fluorescent group to Y9 or K216 was possible using, NeutrAvidin (NA) beads that had been preincubated with biotinylated reagent. Alternatively, excess reagent can be removed by a brief incubation with NA beads. We have thus now developed a system for protein labeling with easy removal of excess and used up low-molecular weight reagent. This strategy can conceivably be utilized in future protein purification and labeling experiments.
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