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| 54. |
- Sandgren, M., Gualfetti, P.J., Paech, C., Paech, S., Shaw, A., Gross, L.S., Saldajeno, M., Berglund, G.I., Jones, T.A. & Mitchinson, C.
(author)
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The Humicloa grisea Cel12A enzyme structure at 1.2 Å resolution and the impact of its free cysteine residues on thermal stability
- 2003
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In: Protein Science. ; 12, s. 2782-2793
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Journal article (peer-reviewed)
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| 55. |
- Sandgren, M., Guafetti, P.J., Shaw, A., Day, A.G., Gross, L., Saldajeno, M., Jones,T.A. & Mitchinson, C.
(author)
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Comparison of family 12 glucosyl hydrolases and recruitment of substitutions important for stability
- 2003
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In: Protein Science. ; 12, s. 848-860
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Journal article (peer-reviewed)
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| 56. |
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| 57. |
- Sandgren, Niclas, et al.
(author)
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Spectral analysis of multichannel MRS data
- 2005
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In: Journal of Magnetic Resonance. ; 175:1, s. 79-91
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Journal article (peer-reviewed)abstract
- The use of phased-array receive coils is a well known technique to improve the image quality in magnetic resonance imaging (MRI) studies of, e.g., the human brain. It is common to incorporate proton (1H) magnetic resonance spectroscopy (MRS) experiments in these studies to quantify key metabolites in a region of interest. Detecting metabolites in vivo is often difficult, requiring extensive scans to achieve signal-to-noise ratios (SNR) that provide suitable diagnostic results. Combining the MR absorption spectra obtained from several receive coils is one possible approach to increase the SNR. Previous literature does not give a clear overview of the wide range of possible approaches that can be used to combine MRS data from multiple detector coils. In this paper we consider the multicoil MRS approach and introduce several signal processing tools to address the problem from different nonparametric, semiparametric and parametric perspectives, depending on the amount of available prior knowledge about the data. We present a numerical study of these tools using both simulated 1H MRS data, and experimental MRS data acquired from a 3T MR scanner.
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| 58. |
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| 59. |
- Sandgren, Per, et al.
(author)
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Stratigraphic evidence for a high marine shore-line during the Late Weichselian deglaciation on the Kullen Peninsula, southern Sweden
- 1999
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In: Journal of Quaternary Science. - 1099-1417. ; 14:3, s. 223-237
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Journal article (peer-reviewed)abstract
- Mineral magnetic properties and the carbon content of a sediment sequence in Lake Kullatorpssjon on the Kullen Peninsula in northwest Scania, southern Sweden, were investigated. Diatom and ostracod analyses were undertaken for palaeoecological reconstruction and a chronology was constructed from accelerator mass spectrometry (AMS) radiocarbon dating of terrestrial plant remains and mosses. Five stratigraphical units were identified (units 1-5, from oldest to youngest). The two lowermost units consist of clay. The lowest clay unit (1) is strikingly black, 2 m thick and has magnetic properties dominated by high concentrations of authigenic greigite (Fe3S4). In contrast, the overlying clay unit (2) is grey, 1.18 m thick and has magnetic properties dominated by low concentrations of detrital magnetite (Fe3O4). A major palaeoecological change is reflected in the diatom flora and ostracod fauna at the transition from unit 1 to unit 2. The sediment stratigraphy, geochemical, mineral magnetic and palaeoecological analyses also point to a significant change in depositional environment at this transition, which is proposed to represent the isolation of Lake Kullatorpssjon from the Kattegat Sea. Earlier investigations have determined the marine limit to ca. 65 m a.s.l. on the Kullen Peninsula. The separate independent lines of evidence presented here, however, suggest that the Late Weichselian marine limit developed at 85-90 m a.s.l. at the deglaciation ca. 17 200 cal. yr BP (ca. 14 500 yr BP). This limit is ca. 25 m higher than assumed previously. Lake Kullatorpssjon formed ca. 1000 cal. yr later when the basin became isolated from the Kattegat Sea. Copyright (C) 1999 John Wiley & Sons, Ltd.
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| 60. |
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| 61. |
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| 62. |
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| 63. |
- Satkunas, J, et al.
(author)
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Upper Pleistocene stratigraphy at the Medininkai site, eastern Lithuania: a continuous record of the Eemian-Weichselian sequence
- 2003
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In: Boreas. - : Wiley. - 1502-3885 .- 0300-9483. ; 32:4, s. 627-641
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Journal article (peer-reviewed)abstract
- Eemian-Weichselian sequences, located outside the maximum limit of the Late Weichselian ice sheet, provide excellent opportunities for the discovery of continuous sedimentary records encompassing the whole Last Interglacial/Glacial cycle. Such a sequence is recorded in a borehole (117P) through the succession in a small kettlehole lake located at Medininkai, eastern Lithuania. The succession consists of peat, gyttja and silt deposited on top of a Saalian till. Pollen and plant macrofossil analysis, lithological analysis, U/Th dating and mineral magnetic measurements on the sediments have allowed 19 lithostratigraphic units and 16 local pollen assemblage zones (LPAZ) to be identified. The palaeocarpological record reveals a clear transition from the Saalian Glacial to the Weichselian stadial and interstadial phases. The mineral magnetic parameters suggest a good correlation between the concentration of magnetic minerals and stadial and interstadial periods. The Merkine (Eemian) Interglacial and two Early Weichselian Interstadials, Jonionys 1 (Brorup) and Jonionys 2 (Odderade), separated by cryomers, are identified. Intervals interpreted as analogous to the Middle Weichselian Denekamp and Hengelo interstadials are also recognized on the basis of pollen assemblages. The results show alternating periglacial and interstadial palaeoenvironments in Lithuania during the Early and Middle Weichselian and are of importance for Late Pleistocene palaeoenvironmental reconstruction of the Baltic area as a whole.
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| 64. |
- Skioldebrand, E, et al.
(author)
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Enhanced concentration of COMP (cartilage oligomeric matrix protein) in osteochondral fractures from racing Thoroughbreds
- 2005
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In: Journal of Orthopaedic Research. - : Wiley. - 1554-527X .- 0736-0266. ; 23:1, s. 156-163
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Journal article (peer-reviewed)abstract
- The aim of the present study was to correlate the levels of COMP and aggrecan as indicators of tissue damage, in synovial fluid (sf) from carpal joints of acutely lame racehorses, with macroscopical lesions of articular cartilage (OA). osteochondral fractures and ligament tears found at arthroscopy. Sixty-three lame horses [49 Standardbred trotters (STB) and 14 Thoroughbreds (TB)] in conventional training and racing that underwent arthroscopy of their middle carpal or radiocarpal joints were included in the study. Intact as well as fragmented COMP and aggrecan released into the synovial fluid were quantified by western blot analyses and ELISA. The expression of COMP in tissues was estimated by mRNA in situ hybridisation and protein immununolocalisation in cartilage and osteochondral fractures. The concentration of sf-COMP was higher in TB with an osteochondral fracture than in STB with osteochondral fractures and TB and STB with OA. The chondrocytes in middle and deep zones of the articular cartilage of the osteochondral fragments (from a TB) expressed COMP mRNA, in contrast to the cartilage on the opposite side of the fracture where no expression was detected. In the synovial fluid from a joint (TB) with osteochondral fractures only intact COMP was present, whereas, fragmented COMP was more prominent in synovial fluid from a joint with OA. The concentration of sf-aggrecan did not differ between the two breeds, or between different lesions. The increased concentration of sf-COMP in TB with osteochondral fractures, but not in synovial fluid from equine joints with OA, is a novel finding. The results from this study indicate that elevated sf-COMP concentration in the joints of Thoroughbreds may be a useful marker for carpal joint osteochondral fragments.
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| 65. |
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| 66. |
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| 67. |
- Torkzad, Michael R., et al.
(author)
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Magnetic resonance imaging and ultrasonography in diagnosis of pelvic vein thrombosis during pregnancy
- 2010
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In: Thrombosis Research. - : Elsevier BV. - 0049-3848 .- 1879-2472. ; 126:2, s. 107-112
-
Journal article (peer-reviewed)abstract
- INTRODUCTION: Pelvic deep vein thrombosis (DVT) is difficult to diagnose during pregnancy. In a two-center trial, we evaluated the agreement between ultrasonography and magnetic resonance imaging (MRI) in diagnosing the extent of DVT into the pelvic veins during pregnancy. MATERIALS AND METHODS: Pregnant women with proximal DVT were examined both with ultrasound and MRI as part of a study designed for treatment of DVT during pregnancy. Ultrasound was performed using color flow by specialist in vascular ultrasound with Doppler and compression techniques. The MRI sequences consisted of a 2D Time of Flight angiography with arterial flow suppression and maximum intensity projection reconstructions; a 3D, T1-w-prepared gradient echo sequence with fat saturation for thrombus imaging; a steady-state free precession sequence; and a Turbo-Spin-Echo. No contrast agent was used. Proportion of agreement (kappa) for detection of DVT in individual veins was measured for different ipsilateral veins and inferior vena cava. RESULTS: All 27 patients were imaged with both techniques at an average gestational age of 29 weeks (range 23-39). Three cases (11.5%) of DVT in the pelvic veins were missed on ultrasound but detected by MRI. The upper limit of the DVT was always depicted at a higher (20 cases, 65.4%) or the same level (seven cases, 34.6%) on MRI than on ultrasound. Agreement expressed as kappa was 0.33 (95% CI 0.27-0.40) demonstrating only fair agreement. In one woman the thrombus had propagated into the inferior vena cava, shown only on MRI. CONCLUSION: Our study suggests that in pregnant women there is only fair agreement between ultrasound and MRI for determination of extent of DVT into pelvic veins, with MRI showing consistently more detailed depiction of extension. Our results indicate that MRI has an important role as a complementary technique in the diagnosis of DVT during pregnancy.
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| 68. |
- Woolcott, Orison O, et al.
(author)
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Arachidonic acid is a physiological activator of the ryanodine receptor in pancreatic beta-cells.
- 2006
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In: Cell Calcium. - : Elsevier BV. - 0143-4160 .- 1532-1991. ; 39:6, s. 529-37
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Journal article (peer-reviewed)abstract
- Pancreatic beta-cells have ryanodine receptors but little is known about their physiological regulation. Previous studies have shown that arachidonic acid releases Ca(2+) from intracellular stores in beta-cells but the identity of the channels involved in the Ca(2+) release has not been elucidated. We studied the mechanism by which arachidonic acid induces Ca(2+) concentration changes in pancreatic beta-cells. Cytosolic free Ca(2+) concentration was measured in fura-2-loaded INS-1E cells and in primary beta-cells from Wistar rats. The increase of cytosolic Ca(2+) concentration induced by arachidonic acid (150microM) was due to both Ca(2+) release from intracellular stores and influx of Ca(2+) from extracellular medium. 5,8,11,14-Eicosatetraynoic acid, a non-metabolizable analogue of arachidonic acid, mimicked the effect of arachidonic acid, indicating that arachidonic acid itself mediated Ca(2+) increase. The Ca(2+) release induced by arachidonic acid was from the endoplasmic reticulum since it was blocked by thapsigargin. 2-Aminoethyl diphenylborinate (50microM), which is known to inhibit 1,4,5-inositol-triphosphate-receptors, did not block Ca(2+) release by arachidonic acid. However, ryanodine (100microM), a blocker of ryanodine receptors, abolished the effect of arachidonic acid on Ca(2+) release in both types of cells. These observations indicate that arachidonic acid is a physiological activator of ryanodine receptors in beta-cells.
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