| 1. |
- Lanke, E., et al.
(författare)
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Co-segregation of the PROS1 locus and protein S deficiency in families having no detectable mutations in PROS1
- 2004
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Ingår i: Journal of Thrombosis and Haemostasis. - : Wiley-Blackwell. - 1538-7933 .- 1538-7836. ; 2:11, s. 1918-1923
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Tidskriftsartikel (refereegranskat)abstract
- Inherited deficiency of protein S constitutes an important risk factor of venous thrombosis. Many reports have demonstrated that causative mutations in the protein S gene are found only in approximately 50% of the cases with protein S deficiency. It is uncertain whether the protein S gene is causative in all cases of protein S deficiency or if other genes are involved in cases where no mutation is identified. The aim of the current study was to determine whether haplotypes of the protein S gene cosegregate with the disease phenotype in cases where no mutations have been found. Eight protein S-deficient families comprising 115 individuals where previous DNA sequencing had failed to detect any causative mutations were analyzed using four microsatellite markers in the protein S gene region. Co-segregation between microsatellite haplotypes and protein S deficiency was found in seven of the investigated families, one family being uninformative. This suggests that the causative genetic defects are located in or close to the protein S gene in a majority of such cases where no mutations have been found.
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| 2. |
- Malm, Karl, et al.
(författare)
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Antithrombotic and anticoagulant effects of wild type and Gla-domain mutated human activated protein C in rats.
- 2007
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Ingår i: Thrombosis Research. - : Elsevier BV. - 1879-2472 .- 0049-3848. ; 120:4, s. 531-539
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Tidskriftsartikel (refereegranskat)abstract
- The antithrombotic and anticoagulant effects of recombinant wild type (WT) and mutated human activated protein C (hAPC) were investigated using a rat model of arterial thrombosis. Recent in vitro studies using human plasma have shown enhanced anticoagulant effects of hAPC by mutagenesis of either loop 148 in the serine protease domain or of the Gla domain. The Gla-domain mutant QGNSEDY-hAPC (=H10Q/S11G/S12N/D23S/Q32E/N33D/H44Y) was found to be particularly active as an anticoagulant. We now combined the two mutations to create the variant QGNSEDY-hAPC:B148 and investigated the in vivo effects of this variant as well as of QGNSEDY-hAPC and WT hAPC using a rat model of arterial thrombosis. In vitro clotting experiments using rat plasma demonstrated WT hAPC to be inefficient, whereas both mutant hAPC variants yielded distinct dose dependent anticoagulant effects. In the arterial injury model, a segment of the left common carotid artery was opened longitudinally. An endarterectomy was performed and the arteriotomy was closed, whereafter the vessel was reperfused and the patency rate determined after 31 min. Three treatment groups each containing 10 rats and a control group of 20 animals were in a blind random fashion given intravenous bolus injections of 0.8 mg/kg WTor mutant hAPC or vehicle only. The ex vivo clotting times of plasma drawn 3 min after the injections, as compared to baseline clotting times, were approximately doubled by QGNSEDY-hAPC and tripled by QGNSEDY-hAPC:B148 infusions, while WT APC had little effect. Compared to the control group, none of the hAPC preparations had significant antithrombotic effect or increased arteriotomy bleeding.
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| 3. |
- Malm, Karl, et al.
(författare)
-
Human activated protein C variants in a rat model of arterial thrombosis
- 2008
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Ingår i: Thrombosis Journal. - : Springer Science and Business Media LLC. - 1477-9560. ; 6
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Activated protein C (APC) inhibits coagulation by degrading activated factor V (FVa) and factor VIII (FVIIIa), protein S (PS) functioning as a cofactor to APC.METHODS: By mutagenesis of the vitamin K-dependent Gla domain of APC, we have recently created an APC variant having enhanced anticoagulant activity due to increased affinity for negatively charged phospholipid membranes. In the present study, the potential antithrombotic effects of this APC variant, and of a variant APC that is additionally mutated in the serine protease domain, have been evaluated in a blind randomized study in a rat model of arterial thrombosis. In this model, we have previously found the combination of bovine APC and PS to be highly antithrombotic. Four treatment groups each containing 10 rats were, in a blind random fashion, given intravenous bolus injections of wild-type or mutant variants of APC (0.8 mg/kg) together with human PS (0.6 mg/kg) or human PS (0.6 mg/kg) alone. A control group with 20 animals where given vehicle only.RESULTS: A trend to increased patency rates was noted in a group receiving one of the APC variants, but it did not reach statistical significance.CONCLUSION: In conclusion, administration of human APC variants having enhanced anticoagulant efficacy together with human PS in a rat model of arterial thrombosis did not give an efficient antithrombotic effect. The lack of effect may be due to species-specific differences between the human protein C system and the rat hemostatic system.
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| 4. |
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| 5. |
- Malm, Karl, et al.
(författare)
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Prevention of thrombosis following deep arterial injury in rats by bovine activated protein C requiring co-administration of bovine protein S.
- 2003
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Ingår i: Thrombosis and Haemostasis. - 0340-6245. ; 90:2, s. 227-234
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Tidskriftsartikel (refereegranskat)abstract
- The antithrombotic effect of bovine activated protein C (bAPC) given with or without bovine protein S (bPS) was investigated in a rat model of deep arterial injury. A segment of the left common carotid artery was isolated between vascular clamps and opened longitudinally. An endarterectomy was performed and the arteriotomy was closed with a running suture, whereafter the vessel was reperfused by removing the clamps. The antithrombotic effect (vascular patency rates 31 minutes after reperfusion) and the arteriotomy bleeding were measured. Ten treatment groups each containing 10 rats and a control group of 20 animals were in a blind random fashion given intravenous bolus injections of increasing doses of activated protein C, with or without co-administration of protein S. The groups received either bAPC alone (0.8, 0.4, 0.2 or 0.1 mg/kg), bAPC (0.8, 0.4, 0.2, 0.1 or 0.05 mg/kg) combined with bPS (0.6 mg/kg), or bPS alone (0.6 mg/kg) whereas the control group received vehicle only. Administered alone, bAPC or bPS had no antithrombotic effect, regardless of dosage. In contrast, all groups that were treated with bAPC in combination with bPS demonstrated a significant antithrombotic effect, as compared to controls. Neither bAPC, bPS, nor the combination of bAPC and bPS increased the arteriotomy bleeding significantly compared to controls. In vitro clotting assays using bAPC or bPS alone yielded only minor prolongation of clotting time, where-as bAPC combined with bPS prolonged the clotting time con-siderably, demonstrating the dependence on the APC-cofactor activity of bPS for expression of anticoagulant activity by bAPC. In conclusion, our study shows the in vivo significance of protein S as a cofactor to activated protein C, and that potent antithrombotic effect can be achieved by low doses of bAPC combined with bPS, without producing hemorrhagic side effects.
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| 6. |
- Ahmad, Abrar, et al.
(författare)
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Evaluation of Expression Level of Apolipoprotein M as a Diagnostic Marker for Primary Venous Thromboembolism
- 2018
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Ingår i: Clinical and Applied Thrombosis/Hemostasis. - : SAGE Publications. - 1938-2723 .- 1076-0296. ; 24:3, s. 416-422
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Tidskriftsartikel (refereegranskat)abstract
- Recently, decreased levels of apolipoprotein M (ApoM) were shown to be associated with higher risk of recurrent venous thromboembolism (VTE) in male patients. However, the role of ApoM in primary VTE is unknown. We aimed in our study to analyze the plasma levels of ApoM in patients with VTE in order to evaluate the diagnostic importance of ApoM in primary VTE. A total of 357 patients with suspected first episode of VTE were recruited prospectively in the SCORE study. Plasma samples from 307 patients were available for quantifying the plasma levels of ApoM in patients with VTE using sandwich enzyme-linked immunosorbent assay method. Among the whole population, plasma levels (mean [standard deviation]) of ApoM were not significantly different between patients with VTE (0.72 [0.20]) and non-VTE patients (0.72 [0.16]), P = .99. Similarly, in regression analyses, no significant association of ApoM plasma levels with the risk of VTE was found on univariate (odds ratio [OR] =1.0, 95% confidence interval [CI] 0.21-4.84, P = .99) and multivariate analysis (OR = 1.25, 95% CI = 0.19-8.34, P = .819) after adjusting for age, body mass index, and smoking. Moreover, results did not differ significantly after stratification of data according to sex ( P > .05). In this study, our results do not suggest a diagnostic role for ApoM plasma levels in patients with primary VTE. Moreover, the current study suggests that role of ApoM as a risk factor may differ for primary VTE and recurrent VTE in male patients.
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| 7. |
- Ahmad, Abrar, et al.
(författare)
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Identification of polymorphisms in Apolipoprotein M gene and their relationship with risk of recurrent venous thromboembolism
- 2016
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Ingår i: Thrombosis and Haemostasis. - 0340-6245. ; 116:3, s. 41-432
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Tidskriftsartikel (refereegranskat)abstract
- Apolipoprotein M (ApoM) plasma levels have been reported to be associated with risk of venous thromboembolism (VTE) recurrence. However, the role of genetic alterations in the ApoM gene in VTE recurrence remains unknown. The aim of this study was to identify genetic aberrations in ApoM gene in VTE recurrence and their role in prediction of VTE recurrence in a prospective follow-up study of 1465 VTE patients. During follow-up, 156 (10.6 %) patients had VTE recurrence. First screening of whole ApoM gene was performed by Sanger's sequencing in selected age and sex matched non-recurrent and recurrent patients (n=95). In total six polymorphisms were identified and two polymorphisms (rs805297 and rs9404941) with minor allele frequency (MAF) ≥5 % were further genotyped in the whole cohort by Taqman PCR. ApoM rs805297 polymorphism was significantly associated with higher risk of VTE recurrence in males but not in females on both univariate (p= 0.038, hazard ratio = 1.72, confidence interval = 1.03-2.88) and on multivariate analysis adjusted with mild and severe thrombophilia, family history, location and acquired risk factors for VTE. However, ApoM rs9404941 polymorphism showed no significant association with risk of VTE recurrence in all patients as well as in different gender groups. Moreover, ApoM rs805297 and rs9404941 polymorphisms were not associated with the ApoM plasma levels. In conclusion, for the first time we have sequenced whole ApoM gene in VTE and identified six polymorphisms. ApoM rs805297 was significantly associated with higher risk of VTE recurrence in male but not in female patients.
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| 8. |
- Ahnström, Josefin, et al.
(författare)
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Activated protein C cofactor function of protein S: a novel role for a gamma-carboxyglutamic acid residue
- 2011
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Ingår i: Blood. - : American Society of Hematology. - 1528-0020 .- 0006-4971. ; 117:24, s. 6685-6693
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Tidskriftsartikel (refereegranskat)abstract
- Protein S has an important anticoagulant function by acting as a cofactor for activated protein C (APC). We recently reported that the EGF1 domain residue Asp95 is critical for APC cofactor function. In the present study, we examined whether additional interaction sites within the Gla domain of protein S might contribute to its APC cofactor function. We examined 4 residues, composing the previously reported "Face1" (N33S/P35T/E36A/Y39V) variant, as single point substitutions. Of these protein S variants, protein S E36A was found to be almost completely inactive using calibrated automated thrombography. In factor Va inactivation assays, protein S E36A had 89% reduced cofactor activity compared with wild-type protein S and was almost completely inactive in factor VIIIa inactivation; phospholipid binding was, however, normal. Glu36 lies outside the omega-loop that mediates Ca2+-dependent phospholipid binding. Using mass spectrometry, it was nevertheless confirmed that Glu36 is gamma-carboxylated. Our finding that Gla36 is important for APC cofactor function, but not for phospholipid binding, defines a novel function (other than Ca2+ coordination/phospholipid binding) for a Gla residue in vitamin K-dependent proteins. It also suggests that residues within the Gla and EGF1 domains of protein S act cooperatively for its APC cofactor function. (Blood. 2011;117(24):6685-6693)
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| 9. |
- Ahnström, Josefin, et al.
(författare)
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HDL Stimulates apoM Secretion.
- 2010
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Ingår i: Protein & Peptide Letters. - 0929-8665. ; Jul 1, s. 1285-1289
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Tidskriftsartikel (refereegranskat)abstract
- Apolipoprotein M (apoM) in human plasma is mainly associated with HDL. A retained signal peptide anchors apoM to the lipoproteins. To investigate the role of the signal peptide in the transfer of apoM from the synthesizing cell to the lipoproteins, wildtype apoM cDNA and the Q(22)A mutant, introducing a signal peptidase cleavage site, were used to stably transfect HEK293 cells, which intrinsically do not express apolipoproteins. When cultured under serum-free conditions, wildtype apoM was, in contrast to Q(22)A, poorly secreted. Addition of serum or purified HDL stimulated secretion of wildtype apoM, which was recovered in the medium incorporated in HDL. The liver cell line HepG2, which synthesizes HDL, was cultured under serum-free conditions and found to secrete apoM as part of an HDL-like particle. In conclusion, due to its retained signal peptide, apoM is poorly secreted unless HDL is either coexpressed or added to the culture medium.
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| 10. |
- Ahnström, Josefin, et al.
(författare)
-
Hydrophobic ligand binding properties of the human lipocalin apolipoprotein M
- 2007
-
Ingår i: Journal of Lipid Research. - 1539-7262. ; 48:8, s. 1754-1762
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Tidskriftsartikel (refereegranskat)abstract
- Apolipoprotein M (apoM) is a plasma protein associated mainly with HDL. ApoM is suggested to be important for the formation of pre beta-HDL, but its mechanism of action is unknown. Homology modeling has suggested apoM to be a lipocalin. Lipocalins share a structurally conserved beta-barrel, which in many lipocalins bind hydrophobic ligands. The aim of this study was to test the ability of apoM to bind different hydrophobic substances. ApoM was produced both in Escherichia coli and in HEK 293 cells. Characterization of both variants with electrophoretic and immunological methods suggested apoM from E. coli to be correctly folded. Intrinsic tryptophan fluorescence of both apoM variants revealed that retinol, all-trans-retinoic acid, and 9-cis-retinoic acid bound ( dissociation constant 5 2-3 mu M), whereas other tested substances ( e.g., cholesterol, vitamin K, and arachidonic acid) did not. The intrinsic fluorescence of two apoM mutants carrying single tryptophans was quenched by retinol and retinoic acid to the same extent as wild-type apoM, indicating that the environment of both tryptophans was affected by the binding. In conclusion, the binding of retinol and retinoic acid supports the hypothesis that apoM is a lipocalin. The physiological relevance of this binding has yet to be elucidated.
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| 11. |
- Ahnström, Josefin, et al.
(författare)
-
Levels of apolipoprotein M are not associated with the risk of coronary heart disease in two independent case-control studies
- 2008
-
Ingår i: Journal of Lipid Research. - 1539-7262. ; 49:9, s. 1912-1917
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Tidskriftsartikel (refereegranskat)abstract
- Apolipoprotein M (apoM), a 25 kDa plasma protein belonging to the lipocalin protein family, is predominantly associated with HDL. Studies in mice have suggested apoM to be important for the formation of pre-beta-HDL and to increase cholesterol efflux from macrophage foam cells. Overexpression of human apoM in LDL receptor-deficient mice reduced the atherogenic effect of a cholesterol-rich diet. The aim of the present study was to investigate whether the apoM levels in man predict the risk for coronary heart disease (CHD). ApoM was measured in samples from two separate case-control studies. FINRISK '92 consisted of 255 individuals, of whom 80 developed CHD during follow-up and 175 were controls. The Copenhagen City Heart Study included 1,865 individuals, of whom 921 developed CHD during follow-up and 944 were controls. Correlation studies of apoM concentration with several analytes showed a marked positive correlation with HDL and total cholesterol as well as with apoA-I and apoB. There was no significant difference in mean apoM level between CHD and control subjects in either study. In conditional logistic regression analyses, apoM was not a predictor of CHD events, [odds ratio (95% CI) 0.97 (0.74-1.27) and 0.92 (0.84-1.02), respectively]. In conclusion, no association between apoM and CHD could be found in this study.-Ahnstrom, J., O. Axler, M. Jauhiainen, V. Salomaa, A. S. Havulinna, C. Ehnholm, R. Frikke-Schmidt, A. Tybjaerg-Hansen, and B. Dahlback. Levels of apolipoprotein M are not associated with the risk of coronary heart disease in two independent case-control studies.
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| 12. |
- Ahnström, Josefin, et al.
(författare)
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Plasma concentrations of apolipoproteins A-I, B, and M in patients with abdominal aortic aneurysms.
- 2010
-
Ingår i: Clinical Biochemistry. - : Elsevier BV. - 1873-2933 .- 0009-9120. ; 43:4-5, s. 407-410
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: Apolipoproteins play important roles in the development of atherosclerosis but their involvement in the pathogenesis of abdominal aortic aneurysm (AAA) is poorly understood. The aim was to investigate whether apoA-I, apoB and apoM are independently associated with AAA. Design and methods: Plasma apoA-I, apoB and apoM were measured in 343 patients with AAA and in 214 elderly apparently healthy control individuals from the background population. Results: AAA patients had lower apolipoprotein levels, as compared to healthy individuals; apoA-I, 1.62 vs. 2.08 g/l; apoB, 0.91 vs. 1.04 g/l; apoM, 0.72 vs. 0.91 mumol/l (p<0.0001 for all three). In multivariate analyses, apoA-I and apoB were associated with AAA, odds ratios (95% confidence intervals) being 0.53 (0.43-0.64) and 0.86 (0.75-0.998), respectively. Conclusions: ApoA-I, apoB and apoM levels were significantly lower in patients with AAA than in the control individuals, but only apoA-I and apoB were independently associated to AAA.
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| 13. |
- Ahnström, Josefin, et al.
(författare)
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Plasma concentrations of apolipoproteins A-I, B, and M in patients with critical limb ischemia.
- 2010
-
Ingår i: Clinical Biochemistry. - : Elsevier BV. - 1873-2933 .- 0009-9120. ; 43, s. 599-603
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: Apolipoproteins affect development of atherosclerosis, but their involvement in the pathogenesis of critical limb ischemia (CLI), a severe form of atherosclerosis, has not previously been examined. DESIGN AND METHODS: ApoA-I, apoB, and apoM were measured in plasma from 196 CLI subjects and 214 control individuals from the background population. RESULTS: Cases had lower levels of the apolipoproteins, as compared to controls; apoA-I, 1.23 vs. 2.08 g/L; apoB, 0.93 vs. 1.04 g/L; apoM, 0.75 vs. 0.91 mumol/L (p<0.0001 for all three). ApoA-I and apoM correlated negatively with inflammatory markers and positively to 1- and 3-year survival rates, whereas apoB did not. In multivariate analyses, apoA-I, but not apoB and apoM, was independently associated with CLI, the odds ratio being 0.015. CONCLUSIONS: In subjects with CLI, plasma concentrations of apoA-I, apoB and apoM were significantly lower than in control individuals, but only apoA-I was independently associated to CLI.
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| 14. |
- Ahnström, Josefin, et al.
(författare)
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Plasma levels of apolipoprotein M in normal and complicated pregnancy.
- 2010
-
Ingår i: Acta Obstetricia et Gynecologica Scandinavica. - : Wiley. - 1600-0412 .- 0001-6349. ; 89:9, s. 1214-1217
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Tidskriftsartikel (refereegranskat)abstract
- Apolipoprotein M (apoM) is mainly associated with high-density lipoprotein in human plasma. Despite several studies suggesting apoM as an anti-atherogenic, its function is not yet fully understood. Plasma apoM was measured in normal pregnancies at four different gestational ages and in the postpartum period to investigate whether the concentration of apoM changes during pregnancy. In addition, apoM was measured at 13 weeks in women who subsequently developed preeclampsia, gestational diabetes, recurrent miscarriage, or small-for-gestational age babies, and in women with uncomplicated pregnancies. The plasma concentrations of apoM increased during pregnancy to reach highest levels in the postpartum period. Thus, plasma apoM in non-pregnant women was around 0.77 micromol/l, 0.88 micromol/l at 40 gestational weeks, and 1.05 micromol/l in the postpartum period (p < 0.0001). No differences in plasma concentrations of apoM were found among the studied pregnancy complications.
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| 15. |
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| 16. |
- Ajzner, E, et al.
(författare)
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Anti-factor V auto-antibody in the plasma and platelets of a patient with repeated gastrointestinal bleeding
- 2003
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Ingår i: Journal of Thrombosis and Haemostasis. - : Elsevier BV. - 1538-7933 .- 1538-7836. ; 1:5, s. 943-949
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Tidskriftsartikel (refereegranskat)abstract
- Development of autoantibody against coagulation factor V (FV) is a rare clinical condition with hemorrhagic complications of varying severity. The aim of this study was to establish the pathomechanism of an acquired FV deficiency and characterize the FV inhibitor responsible for the clinical symptoms. A 78-year-old female was admitted to hospital with severe gastrointestinal bleeding. General clotting tests and determination of clotting factors were performed by standard methods. FV antigen and FV containing immune complexes were measured by ELISA. The FV molecule was investigated by Western blotting and by sequencing the f5 gene. The binding of patient's IgG to FV and activated FV (FVa) was demonstrated in an ELISA system and its effect on the procoagulant activity of FVa was tested in clotting tests and in a chromogenic prothrombinase assay. Localization of the epitope for the antibody was performed by blocking ELISA. FV activity was severely suppressed both in plasma and platelets. FV antigen levels were normal by ELISA using polyclonal anti-FV antibody or monoclonal antibody against the connecting region of FV, but depressed when HV1 monoclonal antibody against the C2 domain in the FV light-chain was used as capture antibody. The FV molecule was found intact. An IgG reacting with both FV and FVa was present in the patient's plasma and its binding to FV was inhibited by HV1 antibody. FV-containing immune complexes were detected in the patient's plasma and platelet lysate. The patient's IgG inhibited the procoagulant function of FVa. An anti-FV IgG was present in the patient's plasma and platelets. The autoantibody reacted with an epitope in the C2 domain of FV light chain and neutralized the procoagulant function of FVa.
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| 17. |
- Andersson, Helena M., et al.
(författare)
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Activated protein C cofactor function of protein S: a critical role for Asp95 in the EGF1-like domain
- 2010
-
Ingår i: Blood. - : American Society of Hematology. - 1528-0020 .- 0006-4971. ; 115:23, s. 4878-4885
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Tidskriftsartikel (refereegranskat)abstract
- Protein S has an established role in the protein C anticoagulant pathway, where it enhances the factor Va (FVa) and factor VIIIa (FVIIIa) inactivating property of activated protein C (APC). Despite its physiological role and clinical importance, the molecular basis of its action is not fully understood. To clarify the mechanism of the protein S interaction with APC, we have constructed and expressed a library of composite or point variants of human protein S, with residue substitutions introduced into the Gla, thrombin-sensitive region (TSR), epidermal growth factor 1 (EGF1), and EGF2 domains. Cofactor activity for APC was evaluated by calibrated automated thrombography (CAT) using protein S-deficient plasma. Of 27 variants tested initially, only one, protein S D95A (within the EGF1 domain), was largely devoid of functional APC cofactor activity. Protein S D95A was, however, gamma-carboxylated and bound phospholipids with an apparent dissociation constant (Kd(app)) similar to that of wildtype (WT) protein S. In a purified assay using FVa R506Q/R679Q, purified protein S D95A was shown to have greatly reduced ability to enhance APC-induced cleavage of FVa Arg306. It is concluded that residue Asp95 within EGF1 is critical forAPC cofactor function of protein S and could define a principal functional interaction site for APC. (Blood. 2010;115(23):4878-4885)
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| 18. |
- Angelillo-Scherrer, Anne, et al.
(författare)
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Deficiency or inhibition of Gas6 causes platelet dysfunction and protects mice against thrombosis
- 2001
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Ingår i: Nature Medicine. - : Springer Science and Business Media LLC. - 1546-170X .- 1078-8956. ; 7:2, s. 215-221
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Tidskriftsartikel (refereegranskat)abstract
- The growth arrest-specific gene 6 product (Gas6) is a secreted protein related to the anticoagulant protein S but its role in hemostasis is unknown. Here we show that inactivation of the Gas6 gene prevented venous and arterial thrombosis in mice, and protected against fatal collagen/epinephrine-induced thrombo embolism. Gas6-/- mice did not, however, suffer spontaneous bleeding and had normal bleeding after tail clipping. In addition, we found that Gas6 antibodies inhibited platelet aggregation in vitro and protected mice against fatal thrombo embolism without causing bleeding in vivo. Gas6 amplified platelet aggregation and secretion in response to known agonists. Platelet dysfunction in Gas6-/- mice resembled that of patients with platelet signaling transduction defects. Thus, Gas6 is a platelet-response amplifier that plays a significant role in thrombosis. These findings warrant further evaluation of the possible therapeutic use of Gas6 inhibition for prevention of thrombosis.
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| 19. |
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| 20. |
- Autin, L, et al.
(författare)
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Proposed structural models of the prothrombinase (FXa-FVa) complex
- 2006
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Ingår i: Proteins. - : Wiley. - 0887-3585. ; 63:3, s. 440-450
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Tidskriftsartikel (refereegranskat)abstract
- Activated coagulation factor V (FVa) functions as a cofactor to factor Xa (FXa) in the conversion of prothrombin (PT) to thrombin. This essential procoagulant reaction, despite being the subject of extensive investigation, is not fully understood structurally and functionally. To elucidate the structure of the FXa-FVa complex, we have performed protein:protein (Pr:Pr) docking simulation with the pseudo-Brownian Pr:Pr docking ICM package and with the shape-complementarity Pr:Pr docking program PPD. The docking runs were carried out using a new model of full-length human FVa and the X-ray structure of human FXa. Five representative models of the FXa-FVa complex were in overall agreement with some of the available experimental data, but only one model was found to be consistent with almost all of the reported experimental results. The use of hybrid docking approach (theoretical plus experimental) is definitively important to study such large macromolecular complexes. The FXa-FVa model we have created will be instrumental for further investigation of this macromolecular system and will guide future site directed mutagenesis experiments.
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| 21. |
- Axler, Olof, et al.
(författare)
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An ELISA for apolipoprotein M reveals a strong correlation to total cholesterol in human plasma
- 2007
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Ingår i: Journal of Lipid Research. - 1539-7262. ; 48:8, s. 1772-1780
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Tidskriftsartikel (refereegranskat)abstract
- Apolipoprotein M (apoM) is a 188 amino acid, 25 kDa protein belonging to the lipocalin protein superfamily. Although predominantly associated with high density lipoprotein, apoM is found in all major lipoprotein classes. To facilitate clinical studies of apoM, we have developed a sandwich ELISA for the measurement of apoM in human plasma. This method has been used to investigate normal apoM variation and to establish reference values for healthy individuals through the measurement of 598 samples from the Nordic Reference Interval Project Bio-bank and Database ( NOBIDA) biobank. For women 18-49 years old, the reference interval for apoM was 0.58-1.18 mu mol/l, whereas for women 501 years and for men, the reference range was 0.61-1.30 mu mol/l. Correlation studies of apoM with 26 common clinical chemical analytes from the NOBIDA database revealed a marked positive correlation with plasma total cholesterol (r = 0.52) and LDL and HDL cholesterol ( r = 0.43 and 0.36, respectively). There was no statistically significant correlation with HDL/total cholesterol ratio or body mass index. In conclusion, a sandwich ELISA for the measurement of apoM in human plasma shows that apoM concentration is strongly correlated to total cholesterol in healthy individuals.
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| 22. |
- Axler, Olof, et al.
(författare)
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Apolipoprotein M associates to lipoproteins through its retained signal peptide.
- 2008
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Ingår i: FEBS Letters. - : Wiley. - 1873-3468 .- 0014-5793. ; 582:5, s. 826-828
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Tidskriftsartikel (refereegranskat)abstract
- Apolipoprotein M (apoM) is predominantly associated with HDL. In this study, it was investigated whether apoM's uncleaved signal peptide is necessary for the protein's ability to associate with lipoproteins. ApoM with a cleavable signal peptide, Q22A, was expressed, together with wild-type apoM, in HEK293 cells. On size-exclusion chromatography, the elution profile of wild-type apoM was similar to that of human HDL-associated plasma apoM. In contrast, the size of the Q22A mutant corresponded to free, unassociated apoM. This strongly indicates that the signal peptide is indeed necessary for apoM's ability to associate with lipid.
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| 23. |
- Balogh, Istvan, et al.
(författare)
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Analysis of Gas6 in Human Platelets and Plasma.
- 2005
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Ingår i: Arteriosclerosis, Thrombosis and Vascular Biology. - 1524-4636. ; 25:6, s. 1280-1286
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Tidskriftsartikel (refereegranskat)abstract
- Objective - Gas6 is a member of the vitamin K-dependent protein family. Gas6- deficient mice were found to be resistant to thrombosis because of defective platelet function. Mouse Gas6 was demonstrated to be present in platelets and found to be involved in platelet aggregation. The aim of this study was to investigate the presence of Gas6 in human platelets and plasma and determine its role in platelet function. Methods and Results - The presence of Gas6 in human platelets and plasma was analyzed using sensitive immunologic methods. Mass spectrometry and ELISA were used to identify and quantify Gas6 in plasma. Gas6 was demonstrated to be present in human plasma, at a concentration determined to be 13 to 23 ng/mL (0.16 to 0.28 nM). Furthermore, plasma Gas6 levels were found to be lower in patients administered with warfarin. However, Gas6 was undetectable in human platelets. Conclusions - This is the first report to identify and quantify Gas6 in human plasma. However, Gas6 protein was not detected in human platelets, suggesting that any potential platelet-specific function could be because of Gas6 from the circulation. These findings open up new directions regarding the role of Gas6 in normal and pathophysiological situations such as inflammation, autoimmune disease, thrombosis and arteriosclerosis.
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| 24. |
- Bengtsson, A, et al.
(författare)
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Factor V:Q506 mutation and anticardiolipin antibodies in systemic lupus erythematosus
- 1996
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Ingår i: Lupus. - : SAGE Publications. - 0961-2033 .- 1477-0962. ; 5:6, s. 598-601
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Tidskriftsartikel (refereegranskat)abstract
- Inherited resistance to activated protein C (APC resistance) is an important risk factor of venous thrombosis. It is caused by a point mutation in the gene coding for coagulation factor V, called FV:Q506. Arterio-venous thrombosis is a common and serious medical problem in patients with systemic lupus erythematosus (SLE). We studied the prevalence of the factor V mutation associated with APC resistance and IgG anticardiolipin antibodies (aCLs) in an epidemiological cohort of 78 Swedish SLE patients, to determine their roles as risk factors for thrombosis. In addition, a detailed evaluation of the clinical manifestations in these patients was performed. Totally, 19 (24%) of the 78 SLE patients had thrombosis, 11 (14%) had venous thrombosis and 8 (10%) had a cerebral infarction caused by occlusion of cerebral vessels. Twenty-six (33%) SLE patients were aCL positive and 8 (10%) were heterozygous for the factor V mutation. Only one of the patients with venous thrombosis and one of the patients with cerebral thrombosis had the FV:Q506 mutation, whereas 3 patients with venous thrombosis and 5 patients with cerebral infarction were aCL positive. Eleven of 19 patients with heart valve disease were aCL positive, a statistically significant association (P = 0.01). In conclusion, we found no statistically significant association between venous thrombosis and FV:Q506 mutation or venous thrombosis and aCL positivity. There was, however, an association between heart valve disease and aCL positivity.
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| 25. |
- Berggren, Peter, 1971-
(författare)
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Assessing Shared Strategic Understanding
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis describes the development of an instrument for assessing shared understanding in teams. The purpose was to develop an instrument that would be usable, understandable, objective, flexible and self-explanatory. Teams working in naturalistic settings are expected to have a shared understanding concerning common goals and how to achieve these. The problem investigated in this thesis is that current techniques and instruments for assessing shared understanding in teams generally suffer from one or more of the following drawbacks, namely that they are expensive, difficult to use, time-consuming, requiring expertise, and are often based on subjective perceptions. Departing from existing theory in team cognition techniques and theories, the research questions posed in this thesis are: 1) How can shared understanding be measured without the disadvantages of existing methods? 2) How can shared understanding be assessed without the bias of self-ratings and/or assessments by experts/observers? 3) Can team performance be better understood by the outcomes of an instrument that measures shared understanding?These research questions are answered through six studies that are presented in this thesis. Over the six studies an instrument was iterated and subsequently developed, called the “shared priorities instrument”. When using this instrument, team members are instructed to generate items and rank these in order of importance. By comparing these rank orders from different participants, a team measure of shared understanding can be calculated. The advantages of this instrument compared to earlier measures are that it is less expensive, easier to use, less time-consuming, does not require subject matter expertise, and that the instrument is distanced from subjective perceptions. Furthermore, the final study provides results where outcomes from the shared priorities instrument correlate with performance, supporting earlier research connecting shared understanding in teams with team performance. A structural equation model, a result of the final study, shows that the instrument is both valid and reliable.
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