| 1. |
- Algaba, Juan-Carlos, et al.
(författare)
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Broadband Multi-wavelength Properties of M87 during the 2017 Event Horizon Telescope Campaign
- 2021
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Ingår i: Astrophysical Journal Letters. - : American Astronomical Society. - 2041-8213 .- 2041-8205. ; 911:1
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Forskningsöversikt (refereegranskat)abstract
- In 2017, the Event Horizon Telescope (EHT) Collaboration succeeded in capturing the first direct image of the center of the M87 galaxy. The asymmetric ring morphology and size are consistent with theoretical expectations for a weakly accreting supermassive black hole of mass ∼6.5 × 109 M o˙. The EHTC also partnered with several international facilities in space and on the ground, to arrange an extensive, quasi-simultaneous multi-wavelength campaign. This Letter presents the results and analysis of this campaign, as well as the multi-wavelength data as a legacy data repository. We captured M87 in a historically low state, and the core flux dominates over HST-1 at high energies, making it possible to combine core flux constraints with the more spatially precise very long baseline interferometry data. We present the most complete simultaneous multi-wavelength spectrum of the active nucleus to date, and discuss the complexity and caveats of combining data from different spatial scales into one broadband spectrum. We apply two heuristic, isotropic leptonic single-zone models to provide insight into the basic source properties, but conclude that a structured jet is necessary to explain M87's spectrum. We can exclude that the simultaneous γ-ray emission is produced via inverse Compton emission in the same region producing the EHT mm-band emission, and further conclude that the γ-rays can only be produced in the inner jets (inward of HST-1) if there are strongly particle-dominated regions. Direct synchrotron emission from accelerated protons and secondaries cannot yet be excluded.
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| 2. |
- Albrektsson, Tomas, 1945, et al.
(författare)
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Histologic investigations on 33 retrieved Nobelpharma implants.
- 1993
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Ingår i: Clinical materials. - 0267-6605. ; 12:1, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- Thirty Nobelpharma implants were retrieved from 17 patients despite a remaining clinical stability, after between 1 and 16 years of clinical function. The reasons for implant removal were bone resorption in combination with soft tissue disorders, psychological causes, implant fracture and post mortem cases. When measured at the cortical passage, there was an average of 84.9% direct bone-to-implant contact and 81.8% average surface bone area in individual threads as evaluated in a computerized morphometric system at the light microscopic level.
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| 3. |
- Alehagen, Urban, et al.
(författare)
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Low plasma concentrations of coagulation factors II, VII and XI indicate increased risk among elderly with symptoms of heart failure.
- 2010
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Ingår i: Blood coagulation & fibrinolysis : an international journal in haemostasis and thrombosis. - 1473-5733. ; 21:1, s. 62-9
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Tidskriftsartikel (refereegranskat)abstract
- Heart failure is a serious condition, and it is, therefore, important to identify patients at high risk as early as possible in order to initiate appropriate treatment. The condition results in complicated disease mechanisms including disturbances in blood coagulation. The aim of the present study was to evaluate whether low plasma concentrations of coagulation factors (F) II, VII and XI influence cardiovascular mortality in an elderly population with possible heart failure. A cardiologist evaluated 450 elderly patients who attended primary healthcare because of symptoms associated with heart failure. He recorded new patient history, conducted a clinical examination, took blood samples, determined concentrations of B-type natriuretic peptide and FII, FVII, FXI and performed Doppler echocardiography. The patients were followed over almost a 10-year period during which all mortality was registered. In patients with suspected heart failure, those with low plasma concentrations of FII, FVII, FXI or all had a significantly higher mortality rate during the follow-up period of 10 years as compared with those with higher plasma concentrations, in contrast with findings in previous reports on patients with acute coronary syndromes. In the group with a plasma concentration of the first versus the ninth decile of FII, FVII, FXI or all, the risk of cardiovascular mortality increased two to three times.
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| 4. |
- Alfredsson, Joakim, et al.
(författare)
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Large early variation of residual platelet reactivity in Acute Coronary Syndrome patients treated with clopidogrel : Results from Assessing Platelet Activity in Coronary Heart Disease (APACHE).
- 2015
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Ingår i: Thrombosis Research. - : Pergamon Press. - 0049-3848 .- 1879-2472. ; 136:2, s. 335-340
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Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION: There is a large inter-individual variation in response to clopidogrel treatment and previous studies have indicated higher risk of thrombotic events in patients with high residual platelet reactivity (HRPR), but the optimal time-point for testing is not established. The aim of this study was to investigate the optimal time-point for aggregometry testing and the risk of major adverse cardiac events associated with HRPR.METHOD AND RESULTS: We included 125 patients with ACS (73 with STEMI, and 71 received abciximab). The prevalence of HRPR varied substantially over time. The rate of HRPR in patients treated and not treated with abciximab were 43% vs 67% (p=0.01) before, 2% vs 23% (p=0.001) 6-8h after, 8% vs 9% (p=0.749) 3days after, and 23% vs 12% (p=0.138) 7-9 days after loading dose of clopidogrel. We found HRPR in 18% of the patients but only four ischemic events during 6months follow-up, with no significant difference between HRPR patients compared to the rest of the population. There were 3 TIMI major bleedings, all of which occurred in the low residual platelet reactivity (LRPR) group.CONCLUSION: There is a large variation in platelet reactivity over time, also depending on adjunctive therapy, which has a large impact on optimal time-point for assessment. We found HRPR in almost 1 in 5 patients, but very few MACE, and not significantly higher in HRPR patients. In a contemporary ACS population, with low risk for stent thrombosis, the predictive value of HRPR for ischemic events will probably be low.
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| 5. |
- Boknäs, Niklas, et al.
(författare)
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Contact activation : important to consider when measuring the contribution of tissue factor-bearing microparticles to thrombin generation using phospholipid-containing reagents
- 2014
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Ingår i: Journal of Thrombosis and Haemostasis. - : John Wiley & Sons. - 1538-7933 .- 1538-7836. ; 12:4, s. 515-518
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Tidskriftsartikel (refereegranskat)abstract
- Background: A commercial MP reagent containing phospholipids is used for thrombin generation (TG) measurements to estimate the procoagulant activity of microparticles (MPs). Previous reports have shown that contact activation affects TG when TF levels are low, and that addition of phospholipids might augment this effect.Objectives: To quantify the impact of contact activation on TG in the presence of phospholipids and low/no TF, as is the case using a commercially available MP-reagent. Methods Thrombin generation was analyzed using MP- or platelet-rich plasma (PRP)-reagent in the presence and absence of corn trypsin inhibitor and anti-TF antibodies, respectively. To quantify the impact of different experimental parameters on contact activation, microparticle-depleted plasma was analyzed in the presence of different concentrations of phospholipids, TF and/or contact activating agents (kaolin).Results: Even with low contact activating blood collection tubes, substantial thrombin generation was observed with the MP-reagent, but this was completely inhibited by addition of corn trypsin inhibitor. Control experiments illustrate that the phospholipids in the reagent play a major role in enhancing TG initiated by FXIIa. Even with the PRP-reagent, which is recommended for determining the content of phospholipids from MPs, TG was partly dependent on contact activation.Conclusions: Contact activation plays a major role in TG when using reagents/samples containing phospholipids but little or no tissue factor. This needs to be considered and accounted for in future clinical studies using TG to assess the procoagulant activity of MPs.
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| 6. |
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| 7. |
- Chaireti, Roza, et al.
(författare)
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Increased thrombin generation in splanchnic vein thrombosis is related to the presence of liver cirrhosis and not to the thrombotic event
- 2014
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Ingår i: Thrombosis Research. - : Elsevier BV. - 0049-3848 .- 1879-2472. ; 134:2, s. 455-461
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Tidskriftsartikel (refereegranskat)abstract
- Background: In recent years there have been increasing evidence associating liver disease with hypercoagulability, rather than bleeding.Aims: To evaluate the haemostatic potential in patients with liver disease.Methods: We measured thrombin generation in the presence and absence of thrombomodulin in patients with portal vein thrombosis (PVT, n=47), Budd-Chiari syndrome (BCS, n=15) and cirrhosis (n=24) and compared the results to those obtained from healthy controls (n=21). Fifteen patients with PVT and 10 patients with BCS were treated with warfarin and were compared with an equal number of patients with atrial fibrillation matched for prothrombin time-international normalized ratio. We assessed resistance to thrombomodulin by using ratios [marker measured in the presence]/[marker measured in the absence of thrombomodulin].Results: There were no differences between patients with BCS, patients on warfarin treatment and controls. Cirrhotic patients generated more thrombin in the presence of thrombomodulin and exhibited thrombomodulin resistance compared with controls [p=0.006 for endogenous thrombin potential (ETP) and p<0.001 for peak thrombin. P<0.001 for both ratios ETP and peak] and patients with non-cirrhotic PVT (p=0.001, p=0.006, p<0.001, p<0.001 for ETP, peak, ratio ETP, ratio peak). The patients with cirrhotic PVT exhibited higher ETP (p=0.044) and peak (p=0.02) in the presence of thrombomodulin than controls, as well as thrombomodulin resistance (ETP ratio: p=0.001, peak ratio: p=0.001).Conclusions: Hypercoagulability and thrombomodulin resistance in patients with cirrhosis were independent of the presence of splanchnic vein thrombosis. The hypercoagulability in patients with cirrhotic PVT could have implications for considering longer treatment with anticoagulants in this group.
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| 8. |
- Chaireti, Roza, et al.
(författare)
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Thrombin generation and D-dimer concentrations in a patient cohort investigated for venous thromboembolism. Relations to venous thrombosis, factor V Leiden and prothrombin G20210A. The LIST study.
- 2009
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Ingår i: Thrombosis Research. - : Elsevier BV. - 0049-3848 .- 1879-2472. ; 124:2, s. 178-84
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Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION: The present study evaluated possible relations between various markers of thrombin generation, D-dimer and venous thromboembolism in outpatients with and without the FV Leiden and the protrombin mutations. PATIENTS AND METHODS: Our cohort consisted of 98 patients with the FV Leiden and 15 with the prothrombin mutation and an equal number of age- and gender-matched controls. All subjects were investigated due to suspicion of venous thromboembolism and the diagnosis was objectively confirmed or refuted. RESULTS: We compared the D-dimer values and the thrombin generation markers among different patient groups (with/without thromboembolism, with/without genetic factors, gender-linked). The only statistically significant difference noted was prolonged time both for the initiation and termination of thrombin generation in patients with thrombosis. This applied to controls and to patients heterozygous for the FV Leiden. Additionally, the D-dimer values were elevated in patients with the FV Leiden. No difference was found among the patients with prothrombin mutation and their controls. DISCUSSION: Multi-variant analysis indicated that the difference in D-dimer between FV Leiden patients and controls was due to the greater number of patients with confirmed thrombosis in the former group, a finding supported by an independent prospective study on postoperative thrombosis. Neither D-dimer concentration nor thrombin generation depend on FV Leiden. The total amount of thrombin generated was not related to diagnosis. The prolonged thrombin generation noted in controls and FV Leiden heterozygotes with thrombosis may point out different thrombin generation profiles in different patient populations and requires further studies.
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| 9. |
- Chaireti, Roza, et al.
(författare)
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Thrombin generation and levels of factor VII activity measured in the presence of rabbit and human thromboplastins in patients with mild factor VII deficiency – effects of mutations in factor VII
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Background/Aim: It is known that spontaneous prolonged prothrombin time-international normalized ratio may be caused by deficiency of factor VII (FVII). The activity of FVII in the presence of thromboplastins of different origin is affected by the presence of specific mutations in the F7 gene. The present study aims to evaluate patients with mild FVII deficiency and somewhat discrepant FVII activity depending on the use of human or rabbit thromboplastin in relation to mutations in the FVII gene and markers of thrombin generation.Patients and methods: A cohort of 10 patients with mild deficiency of FVII and discrepant FVII activity was investigated. The median ratio of the FVII activity in the presence of human/rabbit thromboplastin was 1.4. All but 1 patient had mild to no bleeding symptoms. A genetic analysis of the F7 gene was performed. Thrombin generation was measured by the calibrated automated thrombogram in platelet poor plasma in the presence of human recombinant and different dilutions of rabbit thromboplastin and compared with thrombin generation in healthy controls (n=12). Thrombin generation was measured in 9 patients as 1 was treated with warfarin at the time of the blood sampling.Results: Six previously described mutations were found. Two of those (FVII Padua and FVII Shinjo) are known to affect the results for FVII activity dependent on the species origin of the thromboplastin. Nine out of 10 patients had one mutation in common (Arg353Gln), which however does not affect the binding site of FVII to tissue factor. Lagtime and ttpeak increased with decreasing concentrations of thromboplastin and total and maximum thrombin concentrations increased with increasing thromboplastin concentrations in the patients with FVII deficiency. ETP in patients with FVII deficiency was 86% of ETP in controls.Discussion: The Arg353Gln mutation was very common, however it does not appear to affect the reactivity towards thromboplastins of different origins. Although ETP was higher in the healthy controls, thrombin generation in FVII deficient patients was enough to sustain normal haemostasis. The expected thrombin generation patterns with increasing thromboplastin concentrations were confirmed for the patients in this study.
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