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- Karppinen, Jaro, et al.
(författare)
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Effects of tiaprofenic acid and indomethacin on proteoglycans in the degenerating porcine intervertebral disc.
- 1995
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Ingår i: Spine. - : Wolters Kluwer. - 0362-2436 .- 1528-1159. ; 20:10, s. 1170-1177
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Tidskriftsartikel (refereegranskat)abstract
- STUDY DESIGN: Eighteen pigs were stabbed with a scalpel in the anterior part of the anulus fibrosus of a lumbar disc. After surgery, the pigs received either tiaprofenic acid or indomethacin daily, and a third group did not receive any medication.OBJECTIVES: Nonsteroidal anti-inflammatory agents are widely used in the treatment of low back patients, but their long-term effects on the matrix molecules in the degenerate disc are unknown.SUMMARY OF BACKGROUND DATA: Several in vitro and in vivo studies on articular cartilage have suggested that tiaprofenic acid may not have adverse effects on matrix metabolism, whereas indomethacin probably does.METHODS: Uronic acid, DNA, and water contents were determined from five different locations in each injured disc. Transport and incorporation of sulfate were examined by in vivo radioactive tracer analysis, and proteoglycan structures were analyzed by gel electrophoresis.RESULTS: Morphologically, there were no differences between the treatments. Tiaprofenic acid maintained a higher uronic acid content in the nucleus pulposus and outer anulus compared with that of the nonmedicated animals. Tiaprofenic acid decreased the incorporation of sulfate in the injured area and the water content at most sites. Indomethacin had no adverse effects compared with the nonmedicated group, and it increased water content in the posterior anulus fibrosus.CONCLUSIONS: Long-term administration of tiaprofenic acid and indomethacin did not have harmful effects on matrix metabolism after disc injury. On the contrary, tiaprofenic acid may slightly protect proteoglycans in the degenerating disc.
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| 2. |
- Karppinen, Markku
(författare)
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Crystal structure, atomic net charges and electric moments in pyroelectric LiNaSO4 at 296 K
- 2015
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Ingår i: Acta Crystallographica Section B. - 0108-7681 .- 1600-5740. ; 71, s. 334-341
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Tidskriftsartikel (refereegranskat)abstract
- The crystal structure and electric charge distribution in LiNaSO4 have been studied at 296 K by X-ray diffraction using a spherical crystal. LiNaSO4 is pyroelectric, nonferroelectric and an optically uniaxial insulator which crystallizes in the space group P31c. Least-squares refinement (MOLLY) was based on 13 026 reflections. The asymmetric unit contains Li+, Na+ and three SO42- ions, where one O and S lie on a threefold axis about which three O atoms are related with a threefold symmetry in each sulfate ion. Two of the O-S-O groups suffer from disorder. The net charges of the atoms in three independent sulfate ions were determined under ionic charge constraints. The S atoms have positive net electric charges and O atoms are negative. The components of the significant electric multipole moments in the principal axis directions are determined from the distribution of net atomic charges in each sulfate ion. Electric moments in the unit cell generate macroscopic electric moments in the crystal which interact with light. This interaction results in two axial vectors of second rank associated with an optical indicatrix. The ratio of the calculated axial vector components in the principal axis directions originating from the asymmetric unit is 1.0061 (1), which compares well with the ratio of 1.006 for the corresponding optical refractive indices of LiNaSO4 for lambda(Na) = 589.29 nm.
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| 3. |
- Karppinen, Markku
(författare)
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Net atomic charges, electric moments, and sign and magnitude of optical rotatory power in alpha-TeO2 at 296K
- 2020
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Ingår i: Journal of applied crystallography. - : INT UNION CRYSTALLOGRAPHY. - 0021-8898 .- 1600-5767. ; 53, s. 1252-1256
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Tidskriftsartikel (refereegranskat)abstract
- Optical activity is determined from a point charge model in one enantiomorph of a chiral and semiconducting alpha-TeO2 crystal. Net atomic charges of Te and O atoms are iterated and electric moments derived. Second electric moments in the principal axis directions are calculated and their ratio is fitted by comparison with the corresponding ratio of the optical refraction indices. The components of the axial vectors are calculated and converted to the gyration tensor components. The optical rotatory power in the positive direction of the optic axis is determined, and the sense of optical rotation is defined from transformations of polar vectors of first rank of the TeO2 groups and visually confirmed in both enantiomorphs.
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