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| 2. |
- Abdurahman, Samir, 1965-, et al.
(författare)
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Activity of the small modified amino acid alpha-hydroxy glycineamide on in vitro and in vivo human immunodeficiency virus type 1 capsid assembly and infectivity
- 2008
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Ingår i: Antimicrobial Agents and Chemotherapy. - 0066-4804 .- 1098-6596. ; 52:10, s. 3737-3744
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Tidskriftsartikel (refereegranskat)abstract
- Upon maturation of the human immunodeficiency virus type 1 (HIV-1) virion, proteolytic cleavage of the Gag precursor protein by the viral protease is followed by morphological changes of the capsid protein p24, which will ultimately transform the virus core from an immature spherical to a mature conical structure. Virion infectivity is critically dependent on the optimal semistability of the capsid cone structure. We have reported earlier that glycineamide (G-NH(2)), when added to the culture medium of infected cells, inhibits HIV-1 replication and that HIV-1 particles with aberrant core structures were formed. Here we show that it is not G-NH(2) itself but a metabolite thereof, alpha-hydroxy-glycineamide (alpha-HGA), that is responsible for the antiviral activity. We show that alpha-HGA inhibits the replication of clinical HIV-1 isolates with acquired resistance to reverse transcriptase and protease inhibitors but has no effect on the replication of any of 10 different RNA and DNA viruses. alpha-HGA affected the ability of the HIV-1 capsid protein to assemble into tubular or core structures in vitro and in vivo, probably by binding to the hinge region between the N- and C-terminal domains of the HIV-1 capsid protein as indicated by matrix-assisted laser desorption ionization-mass spectrometry results. As an antiviral compound, alpha-HGA has an unusually simple structure, a pronounced antiviral specificity, and a novel mechanism of antiviral action. As such, it might prove to be a lead compound for a new class of anti-HIV substances.
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| 3. |
- Abrahamsson, Hasse, 1943, et al.
(författare)
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Altered bile acid metabolism in patients with constipation-predominant irritable bowel syndrome and functional constipation
- 2008
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Ingår i: Scandinavian Journal of Gastroenterology. - : Informa UK Limited. - 0036-5521 .- 1502-7708. ; 43:12, s. 1483-1488
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Tidskriftsartikel (refereegranskat)abstract
- Objective. Bile acids are derived from cholesterol and are potent physiological laxatives. The aim of this study was to investigate whether bile acid synthesis is altered in constipation. Material and methods. Female patients with constipation (23 IBS-C, 4 functional constipation (FC)) were studied and compared with non-constipated subjects (16 IBS-D, 20 healthy women). Body mass index (BMI), blood lipids, lanosterol, sitosterol, colonic transit (oro-anal transit time (OATT), reference=4.3 days) and stool frequency were measured. C4 (7--hydroxy-4-cholesten-3-one) levels reflecting bile acid synthesis were measured at 0800 h and 1300 h. Results. When all the groups of constipated and non-constipated subjects were compared, it was found that only stool frequency and OATT differed between groups (p 0.001). When constipated patients were categorized according to OATT, absence of the usual C4 increase at lunchtime was noted in 82% of patients with delayed OATT compared with 17% in subjects with normal OATT (p 0.001). Symptom severity did not differ between groups. A subset of the patients with severely delayed OATT had markedly elevated C4 levels. Conclusions. Patients with IBS-C and FC have marked changes in bile acid synthesis in relation to colonic transit. The diurnal rhythm is altered in the slow transit colon when there is no C4 peak at lunchtime. Alterations in bile acid metabolism may be implicated in the pathophysiology of constipation.
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| 4. |
- Abrahamsson, Katarina, 1957, et al.
(författare)
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Variations of biochemical parameters along a transect in the Southern Ocean, with special emphasis on volatile halogenated organic compounds
- 2004
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Ingår i: Deep-sea research. Part II, Topical studies in oceanography. - : Elsevier BV. - 0967-0645. ; 51:22-24, s. 2745-2756
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Tidskriftsartikel (refereegranskat)abstract
- A number of parameters of biogeochemical interest were monitored along a north-southerly transect (S 43-S 63degrees) in the Atlantic Sector of the Southern Ocean from the 8th to the 20th of December 1997. Changes in total dissolved inorganic carbon (C-T) and total alkalinity (A(T)) were mostly dependent on temperature and salinity until the ice edge was reached. After this point only a weak correlation was seen between these. Highest mean values of C-T and A(T) were observed in the Winter Ice Edge (WIE) (2195 and 2319 mumol kg(-1), respectively). Lowest mean AT (2277 mumol kg(-1)) was observed in the Sub-Antarctic Front (SAF), whereas lowest mean CT concentration (2068 mumol kg(-1)) was associated with the Sub-Tropical Front (STF). The pH in situ varied between 8.060 and 8.156 where the highest values were observed in the southern part of the Antarctic Polar Front (APF) and in the Summer Ice Edge (SIE) Region. These peaks were associated with areas of high chlorophyll a (chl a) and tribromomethane values. In the other areas the pH in situ was mainly dependent on hydrography. Bacterial abundance decreased more than one order of magnitude when going from north to south. The decrease appeared to be strongly related to water temperature and there were no elevated abundances at frontal zones. Microphytoplankton dominated in the SAF and APF, whereas the nano- and picoplankton dominated outside these regions. Volatile halogenated compounds were found to vary both with regions, and with daylight. For the iodinated compounds, the highest concentrations were found north of the STF. Brominated hydrocarbons had high concentrations in the STF, but elevated concentrations were also found in the APF and SIE regions. No obvious correlation could be found between the occurrence of individual halocarbons and chl a. On some occasions trichloroethene and tribromomethane related to the presence of nano- and microplankton, respectively.
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| 5. |
- Abrahamsson, Maria, et al.
(författare)
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Steric influence on the excited-state lifetimes of ruthenium complexes with bipyridyl-alkanylene-pyridyl ligands.
- 2008
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Ingår i: Inorganic Chemistry. - : ACS. - 0020-1669 .- 1520-510X. ; 47:9, s. 3540-3548
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Tidskriftsartikel (refereegranskat)abstract
- The structural effect on the metal-to-ligand charge transfer (MLCT) excited-state lifetime has been investigated in bis-tridentate Ru(II)-polypyridyl complexes based on the terpyridine-like ligands [6-(2,2'-bipyridyl)](2-pyridyl)methane (1) and 2-[6-(2,2'-bipyridyl)]-2-(2-pyridyl)propane (2). A homoleptic ([Ru(2)(2)](2+)) and a heteroleptic complex ([Ru(ttpy)(2)](2+)) based on the new ligand 2 have been prepared and their photophysical and structural properties studied experimentally and theoretically and compared to the results for the previously reported [Ru(1)(2)](2+). The excited-state lifetime of the homoleptic Ru-II complex with the isopropylene-bridged ligand 2 was found to be 50 times shorter than that of the corresponding homoleptic Ru-II complex of ligand 1, containing a methylene bridge. A comparison of the ground-state geometries of the two homoleptic complexes shows that steric interactions involving the isopropylene bridges make the coordination to the central Ru-II ion less octahedral in [Ru(2)(2)](2+) than in [Ru(1)(2))(2+). Calculations indicate that the structural differences in these complexes influence their ligand field splittings as well as the relative stabilities of the triplet metal-to-ligand charge transfer ((MLCT)-M-3) and metal-centered ((MC)-M-3) excited states. The large difference in measured excited-state lifetimes for the two homoleptic Ru-II complexes is attributed to a strong influence of steric interactions on the ligand field strength, which in turn affects the activation barriers for thermal conversion from (MLCT)-M-3 states to short-lived (MC)-M-3 states.
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| 6. |
- Abramsson, Alexandra, 1973, et al.
(författare)
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Defective N-sulfation of heparan sulfate proteoglycans limits PDGF-BB binding and pericyte recruitment in vascular development
- 2007
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Ingår i: GENES & DEVELOPMENT. - : Cold Spring Harbor Laboratory. - 0890-9369 .- 1549-5477. ; 21:3, s. 316-331
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Tidskriftsartikel (refereegranskat)abstract
- During vascular development, endothelial platelet-derived growth factor B (PDGF-B) is critical for pericyte recruitment. Deletion of the conserved C-terminal heparin-binding motif impairs PDGF-BB retention and pericyte recruitment in vivo, suggesting a potential role for heparan sulfate (HS) in PDGF-BB function during vascular development. We studied the participation of HS chains in pericyte recruitment using two mouse models with altered HS biosynthesis. Reduction of N-sulfation due to deficiency in N-deacetylase/N-sulfotransferase-1 attenuated PDGF-BB binding in vitro, and led to pericyte detachment and delayed pericyte migration in vivo. Reduced N-sulfation also impaired PDGF-BB signaling and directed cell migration, but not proliferation. In contrast, HS from glucuronyl C5-epimerase mutants, which is extensively N- and 6-O-sulfated, but lacks 2-O-sulfated L-iduronic acid residues, retained PDGF-BB in vitro, and pericyte recruitment in vivo was only transiently delayed. These observations were supported by in vitro characterization of the structural features in HS important for PDGF-BB binding. We conclude that pericyte recruitment requires HS with sufficiently extended and appropriately spaced N-sulfated domains to retain PDGF-BB and activate PDGF receptor β (PDGFRβ) signaling, whereas the detailed sequence of monosaccharide and sulfate residues does not appear to be important for this interaction.
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| 7. |
- Adenfelt, Maria, et al.
(författare)
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Knowledge development and sharing in multinational corporations : The case of a centre of excellence and a transnational team
- 2006
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Ingår i: International Business Review. - : Elsevier BV. - 0969-5931 .- 1873-6149. ; 15:4, s. 381-400:15 (4), s. 381-400
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we link the discussion on the differentiated multinational corporation (MNC) with organisational mechanisms for knowledge development and sharing. The aim is to explore the impact of different organisational mechanisms on knowledge development and sharing. Using case-study data-drawn from the same MNC-to explore two different organisational mechanisms, a Centre of Excellence and a transnational team, the findings illustrate how multifaceted knowledge development and sharing are. The organisational structure of the two organisational mechanisms partly determines whether knowledge development occurs locally or globally. This, in turn, has consequences for how knowledge sharing evolves. The sharing process is like a double-edged sword: how to share globally while allowing for local adaptations or how to share locally while developing global knowledge.
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| 8. |
- Adolfsson, Jan, et al.
(författare)
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Clinical characteristics and primary treatment of prostate cancer in Sweden between 1996 and 2005
- 2007
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Ingår i: Scandinavian Journal of Urology and Nephrology. - : Informa UK Limited. - 0036-5599 .- 1651-2065. ; 41:6, s. 456-477
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: The incidence of prostate cancer is rising rapidly in Sweden and there is a need to better understand the pattern of diagnosis, tumor characteristics and treatment. MATERIAL AND METHODS: Between 1996 and 2005, all new cases of adenocarcinoma of the prostate gland were intended to be registered in the National Prostate Cancer Register (NPCR). This register contains information on diagnosing unit, date of diagnosis, cause of diagnosis, tumor grade, tumor stage according to the TNM classification in force, serum prostate-specific antigen (PSA) levels at diagnosis and primary treatment given within the first 6 months after diagnosis. RESULTS: In total, 72,028 patients were registered, comprising >97% of all pertinent incident cases of prostate cancer in the Swedish Cancer Register (SCR). During the study period there was a considerable decrease in median age at the time of diagnosis, a stage migration towards smaller tumors, a decrease in median serum PSA values at diagnosis, a decrease in the age-standardized incidence rate of men diagnosed with distant metastases or with a PSA level of > 100 ng/ml at diagnosis and an increase in the proportion of tumors with Gleason score <6. Relatively large geographical differences in the median age at diagnosis and the age-standardized incidence of cases with category T1c tumors were observed. Treatment with curative intent increased dramatically and treatment patterns varied according to geographical region. In men with localized tumors and a PSA level of <20 ng/ml at diagnosis, expectant treatment was more commonly used in those aged > or =75 years than in those aged <75 years. Also, the pattern of endocrine treatment varied in different parts of Sweden. CONCLUSIONS: All changes in the register seen over time are consistent with increased diagnostic activity, especially PSA testing, resulting in an increased number of cases with early disease, predominantly tumors in category T1c. The patterns of diagnosis and treatment of prostate cancer vary considerably in different parts of Sweden. The NPCR continues to be an important source for research, epidemiological surveillance of the incidence, diagnosis and treatment of prostate cancer.
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| 9. |
- Ah-King, M., et al.
(författare)
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Why is there no sperm competition in a pipefish with externally brooding males? Insights from sperm activation and morphology
- 2006
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Ingår i: Journal of Fish Biology. - : Wiley. - 0022-1112 .- 1095-8649. ; 68:3, s. 958-962
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Tidskriftsartikel (refereegranskat)abstract
- Nerophis ophidion sperm activation and morphology were investigated with the aim of explaining the apparent lack of sperm competition in this syngnathid with externally brooding males. Nerophis ophidion sperm were activated by a mixture of ovarian fluid and sea water, but not by sea water alone. This indicated that sperm were not shed into the water but needed to be released near the eggs, which probably restrained sperm competition. (c) 2006 The Fisheries Society of the British Isles.
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