| 1. |
- Grimvall, E, et al.
(författare)
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Monitoring of polychlorinated biphenyls in human blood plasma: methodological developments and influence of age, lactation, and fish consumption
- 1997
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Ingår i: Archives of Environmental Contamination and Toxicology. - : Springer Science and Business Media LLC. - 0090-4341 .- 1432-0703. ; 32:3, s. 329-336
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Tidskriftsartikel (refereegranskat)abstract
- Human plasma samples from 50 wives of fishermen have been analyzed with respect to PCBs. The non-ortho-substituted PCB congeners CB-126 and CB-169 were determined by mass spectrometry in negative ion chemical ionization mode, which demonstrated a limit of detection of 30 fg. The recoveries of the internal standards used for determination of ortho-substituted CBs were approximately 95%. Two methods, one gravimetric and the other based on enzymatic determinations of triglycerides, cholesterol and phospholipids, were compared for the determination of total amount of lipids in the plasma samples; the correlation coefficient was 0.82 and the slope 0.98. For practical reasons, enzymatic determinations are recommended for further use. The total, lipid-adjusted concentrations of PCBs in plasma were influenced by age, total lactation time and consumption of fatty fish from the Baltic Sea.
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| 2. |
- Jendeberg, L, et al.
(författare)
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Engineering of Fc(1) and Fc(3) from human immunoglobulin G to analyse subclass specificity for staphylococcal protein A.
- 1997
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Ingår i: JIM - Journal of Immunological Methods. - 0022-1759 .- 1872-7905. ; 201:1, s. 25-34
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Tidskriftsartikel (refereegranskat)abstract
- A system for production of recombinant Fc fragments of human IgG in Escherichia coli has been developed to allow for structural and functional studies of human Fc. The genes for the Fc fragments of human IgG subclasses 1 and 3, designated Fc(1) and Fc(3), were cloned from a human spleen cDNA library. The interactions to Staphylococcal protein A (SpA), a bacterial Fc receptor, that interacts with human IgG-Fc(1), but not with human IgG-Fc(3), were analyzed. To corroborate the involvement of amino acid residues in Fc, responsible for these differences in binding, two Fc variants were constructed; Fc(1(3)) and Fc(3(1)), each containing an isotypic dipeptide substitution. Production levels in E. coli of 1-10 mg/l of secreted Fc proteins, covalently linked as dimers, were routinely obtained. SpA-binding analyses of all four Fc variants using biosensor technology, showed that Fc(1) and Fc(3(1)) interact with SpA, while Fc(3) and Fc(1(3)) lack detectable SpA binding. The rendered SpA binding of the Fc variant Fc(3(1)), is concluded to result from the introduced dipeptide substitution (R435H, F436Y). The results demonstrate that the Fc expression system efficiently can be used in Fc engineering.
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| 3. |
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| 6. |
- Arnadottir, Margret, et al.
(författare)
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Adrenocorticotrophic hormone lowers serum Lp(a) and LDL cholesterol concentrations in hemodialysis patients
- 1997
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Ingår i: Kidney International. - : Elsevier BV. - 1523-1755 .- 0085-2538. ; 52:6, s. 1651-1655
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Tidskriftsartikel (refereegranskat)abstract
- Previously, we have shown that short-term administration of adrenocorticotrophic hormone (ACTH) results in reduced concentrations of apolipoprotein B-containing lipoproteins, including lipoprotein(a), and reduced activities of hepatic lipase. These effects were observed in steroid-treated patients suffering from iatrogenic ACTH deficiency and in healthy individuals. The direct nature of the influence of ACTH on hepatic lipoprotein metabolism was confirmed by in vitro experiments. The aim of the present investigation was to study the effects of ACTH treatment on uremic patients, who exhibit disturbed lipoprotein pattern due to the slow removal of triglyceride-rich lipoproteins and who probably are ACTH resistant. Eight patients on chronic hemodialysis were studied. After one intramuscular injection of Synacthen Depot (a synthetic ACTH1-24 preparation from Ciba Geigy AG, Basel, Switzerland) 1 mg, the only change noted was a significant reduction of 26% in median lipoprotein(a) concentration. After five injections, a further decrease (65%) was found in the lipoprotein(a) concentration. Also, reductions in median concentrations of total cholesterol, low density lipoprotein cholesterol and apolipoprotein B were observed. The magnitude of these changes was 15 to 30%. In contrast to previously studied groups, no changes were observed regarding triglyceride metabolism. Significantly increased median concentration of apolipoprotein CIII was found. However, the excess apolipoprotein CIII was confined to the fraction that was not associated with apolipoprotein B. Thus, administration of ACTH to uremic patients improved their atherogenic lipoprotein profile, a fact that may have future therapeutic implications. In comparison to previously studied groups, the uremic patients responded rather slowly and not at all regarding triglyceride metabolism.
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| 7. |
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| 8. |
- Brånemark, Rickard, 1960, et al.
(författare)
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Biomechanical characterization of osseointegration during healing: an experimental in vivo study in the rat.
- 1997
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Ingår i: Biomaterials. - 0142-9612. ; 18:14, s. 969-78
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Tidskriftsartikel (refereegranskat)abstract
- This study reports torsion tests and pull-out tests on osseointegrated commercially pure titanium fixtures. The tests were performed in vivo on a total of 26 rats. Three fixtures with a diameter of 2.0 mm were installed bilaterally in the proximal tibia in each animal. The mechanical testing was performed immediately after installation, after 2, 4, 8 and 16 weeks of unloaded healing. The torsional strength started to increase after 4 weeks of unloaded healing and there was a significant increase with time during the initial 16 weeks. The pull-out load increased rapidly during the first 4 weeks; thereafter, a moderate increase occurred during the following 12 weeks. A histological evaluation was performed after 0, 4, 8 and 16 weeks. There were significant (P < 0.01) correlations between torque and percentage of bone in contact with the fixture, and between pull-out load and the bone thickness around the fixture (P < 0.001). Estimations of shear stresses and shear moduli in the bone tissue (pull-out test) and at the interface (torque test) indicated that the increase in bone volume around the implant substantially improved the mechanical capacity.
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| 10. |
- Kimme, Peter, et al.
(författare)
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Cerebral blood flow of the exposed brain surface measured by laser Doppler perfusion imaging
- 1997
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Ingår i: Acta Physiologica Scandinavica. - 0001-6772 .- 1365-201X. ; 159:1, s. 15-22
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Tidskriftsartikel (refereegranskat)abstract
- A novel application of laser Doppler flowmetry (LDF), laser Doppler perfusion imaging (LDPI), was used to study cerebral cortical blood flow (CBFcortex). In contrast to the conventional laser Doppler perfusion monitor, LDPI creates two-dimensional maps of the tissue perfusion in a well defined area of up to 120×120 mm comprising 4096 measurement points. Measurements of CBFcortex were made through an optically transparent polyester film applied to a cranial window preparation in ventilated anaesthetized pigs. Temporal and spatial heterogeneity in CBFcortex were visualized by LDPI during provocations which are known to alter CBF (varying arterial PCO2 or MABP, or infusion of adenosine at constant MABP (concomitant angiotensin administration) or by hyperoxemia). During hypercapnia the recorded CBFcortex increased homogeneously. The adenosine-mediated increase in recorded CBFcortex was concentrated on the lower flow interval, as was the hyperoxemia-caused decline. At decreasing MABP the autoregulatory threshold was found to vary locally within the cortex. The results suggest that LDPI, apart from detecting localized changes in CBFcortex, also visualizes flow changes within different vascular segments. Together with the practical advantages of the system, i.e. not necessitating direct contact with the tissues, this feature makes the technique suitable for studies of CBFcortex distributions.
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