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- Meyer, H., et al.
(author)
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Overview of progress in European medium sized tokamaks towards an integrated plasma-edge/wall solution
- 2017
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In: Nuclear Fusion. - : Institute of Physics Publishing (IOPP). - 0029-5515 .- 1741-4326. ; 57:10
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Journal article (peer-reviewed)abstract
- Integrating the plasma core performance with an edge and scrape-off layer (SOL) that leads to tolerable heat and particle loads on the wall is a major challenge. The new European medium size tokamak task force (EU-MST) coordinates research on ASDEX Upgrade (AUG), MAST and TCV. This multi-machine approach within EU-MST, covering a wide parameter range, is instrumental to progress in the field, as ITER and DEMO core/pedestal and SOL parameters are not achievable simultaneously in present day devices. A two prong approach is adopted. On the one hand, scenarios with tolerable transient heat and particle loads, including active edge localised mode (ELM) control are developed. On the other hand, divertor solutions including advanced magnetic configurations are studied. Considerable progress has been made on both approaches, in particular in the fields of: ELM control with resonant magnetic perturbations (RMP), small ELM regimes, detachment onset and control, as well as filamentary scrape-off-layer transport. For example full ELM suppression has now been achieved on AUG at low collisionality with n = 2 RMP maintaining good confinement H-H(98,H-y2) approximate to 0.95. Advances have been made with respect to detachment onset and control. Studies in advanced divertor configurations (Snowflake, Super-X and X-point target divertor) shed new light on SOL physics. Cross field filamentary transport has been characterised in a wide parameter regime on AUG, MAST and TCV progressing the theoretical and experimental understanding crucial for predicting first wall loads in ITER and DEMO. Conditions in the SOL also play a crucial role for ELM stability and access to small ELM regimes.
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3. |
- Meyer, H., et al.
(author)
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Overview of progress in European medium sized tokamaks towards an integrated plasma-edge/wall solution
- 2017
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In: Nuclear Fusion. - : Institute of Physics Publishing (IOPP). - 0029-5515 .- 1741-4326. ; 57:10
-
Journal article (peer-reviewed)abstract
- Integrating the plasma core performance with an edge and scrape-off layer (SOL) that leads to tolerable heat and particle loads on the wall is a major challenge. The new European medium size tokamak task force (EU-MST) coordinates research on ASDEX Upgrade (AUG), MAST and TCV. This multi-machine approach within EU-MST, covering a wide parameter range, is instrumental to progress in the field, as ITER and DEMO core/pedestal and SOL parameters are not achievable simultaneously in present day devices. A two prong approach is adopted. On the one hand, scenarios with tolerable transient heat and particle loads, including active edge localised mode (ELM) control are developed. On the other hand, divertor solutions including advanced magnetic configurations are studied. Considerable progress has been made on both approaches, in particular in the fields of: ELM control with resonant magnetic perturbations (RMP), small ELM regimes, detachment onset and control, as well as filamentary scrape-off-layer transport. For example full ELM suppression has now been achieved on AUG at low collisionality with n = 2 RMP maintaining good confinement H-H(98,H-y2) approximate to 0.95. Advances have been made with respect to detachment onset and control. Studies in advanced divertor configurations (Snowflake, Super-X and X-point target divertor) shed new light on SOL physics. Cross field filamentary transport has been characterised in a wide parameter regime on AUG, MAST and TCV progressing the theoretical and experimental understanding crucial for predicting first wall loads in ITER and DEMO. Conditions in the SOL also play a crucial role for ELM stability and access to small ELM regimes.
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4. |
- Labit, B., et al.
(author)
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Dependence on plasma shape and plasma fueling for small edge-localized mode regimes in TCV and ASDEX Upgrade
- 2019
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In: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 59:8
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Journal article (peer-reviewed)abstract
- © 2019 Institute of Physics Publishing. All rights reserved. Within the EUROfusion MST1 work package, a series of experiments has been conducted on AUG and TCV devices to disentangle the role of plasma fueling and plasma shape for the onset of small ELM regimes. On both devices, small ELM regimes with high confinement are achieved if and only if two conditions are fulfilled at the same time. Firstly, the plasma density at the separatrix must be large enough (ne,sep/nG ∼ 0.3), leading to a pressure profile flattening at the separatrix, which stabilizes type-I ELMs. Secondly, the magnetic configuration has to be close to a double null (DN), leading to a reduction of the magnetic shear in the extreme vicinity of the separatrix. As a consequence, its stabilizing effect on ballooning modes is weakened.
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10. |
- El-Jawahri, Areej, et al.
(author)
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Impact of pre-transplant depression on outcomes of allogeneic and autologous hematopoietic stem cell transplantation
- 2017
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In: Cancer. - : Wiley. - 0008-543X .- 1097-0142. ; 123:10, s. 1828-1838
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Journal article (peer-reviewed)abstract
- BACKGROUND: To evaluate the impact of depression before autologous and allogeneic hematopoietic cell transplantation (HCT) on clinical outcomes post-transplantation.METHODS: We analyzed data from the Center for International Blood and Marrow Transplant Research to compare outcomes after autologous (n=3786) or allogeneic (n=7433) HCT for adult patients with hematologic malignancies with an existing diagnosis of pre-HCT depression requiring treatment versus those without pre-HCT depression. Using Cox regression models, we compared overall survival (OS) between patients with or without depression. We compared the number of days alive and out of the hospital in the first 100 days post-HCT using Poisson models. We also compared the incidence of grade 2-4 acute and chronic graft-versus-host disease (GVHD) in allogeneic HCT.RESULTS: The study included 1116 (15%) patients with pre-transplant depression and 6317 (85%) without depression who underwent allogeneic HCT between 2008 and 2012. Pre-transplant depression was associated with lower OS (hazard ratio [HR], 1.13; 95% confidence interval [CI], 1.04-1.23; P=0.004) and a higher incidence of grade 2-4 acute GVHD (HR, 1.25; 95% CI, 1.14-1.37; P<0.0001), but similar incidence of chronic GVHD. Pre-transplant depression was associated with fewer days-alive-and-out-of-the hospital (means ratio [MR]=0.97; 95% CI, 0.95-0.99; P=0.004). There were 512 (13.5%) patients with Pre-transplant depression and 3274 (86.5%) without depression who underwent autologous HCT. Pre-transplant depression in autologous HCT was not associated with OS (HR, 1.15; 95% CI, 0.98-1.34; P=0.096) but was associated with fewer days alive and out of the hospital (MR, 0.98; 95% CI, 0.97-0.99; P=0.002).CONCLUSION: Pre-transplant depression was associated with lower OS and higher risk of acute GVHD among allogeneic HCT recipients and fewer days alive and out of the hospital during the first 100 days after autologous and allogeneic HCT. Patients with pre-transplant depression represent a population that is at risk for post-transplant complications.
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11. |
- Liang, Y., et al.
(author)
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Active control of type-I edge localized modes on JET
- 2007
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In: Plasma Physics and Controlled Fusion. - 0741-3335 .- 1361-6587. ; 49:12B, s. B581-B589
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Journal article (peer-reviewed)abstract
- The operational domain for active control of type-I edge localized modes (ELMs) with an n = 1 external magnetic perturbation field induced by the ex-vessel error field correction coils on JET has been developed towards more ITER-relevant regimes with high plasma triangularity, up to 0.45, high normalized beta, up to 3.0, plasma current up to 2.0 MA and q(95) varied between 3.0 and 4.8. The results of ELM mitigation in high triangularity plasmas show that the frequency of type-I ELMs increased by a factor of 4 during the application of the n = 1 fields, while the energy loss per ELM, Delta W/W, decreased from 6% to below the noise level of the diamagnetic measurement (<2%). No reduction of confinement quality (H98Y) during the ELM mitigation phase has been observed. The minimum n = 1 perturbation field amplitude above which the ELMs were mitigated increased with a lower q(95) but always remained below the n = 1 locked mode threshold. The first results of ELM mitigation with n = 2 magnetic perturbations on JET demonstrate that the frequency of ELMs increased from 10 to 35 Hz and a wide operational window of q95 from 4.5 to 3.1 has been found.
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12. |
- Inamoto, Y., et al.
(author)
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Non-Graft-versus-Host Disease Ocular Complications after Hematopoietic Cell Transplantation: Expert Review from the Late Effects and Quality of Life Working Committee of the Center for International Blood and Marrow Transplant Research and the Transplant Complications Working Party of the European Society for Blood and Marrow Transplantation
- 2019
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In: Biology of Blood and Marrow Transplantation. - : Elsevier BV. - 1083-8791. ; 25:5, s. E145-E154
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Journal article (peer-reviewed)abstract
- Non-graft-versus-host disease (GVHD) ocular complications are generally uncommon after hematopoietic cell transplantation (HCT) but can cause prolonged morbidity affecting activities of daily living and quality of life. Here we provide an expert review of non-GVHD ocular complications in a collaboration between transplantation physicians and ophthalmologists through the Late Effects and Quality of Life Working Committee of the Center for International Blood and Marrow Transplant Research and the Transplant Complications Working Party of the European Society of Blood and Marrow Transplantation. Complications discussed in this review include cataracts, glaucoma, ocular infections, ocular involvement with malignancy, ischemic microvascular retinopathy, central retinal vein occlusion, retinal hemorrhage, retinal detachment and ocular toxicities associated with medications. We summarize the incidence, risk factors, screening, prevention, and treatment of individual complications and generate evidence-based recommendations. Baseline ocular evaluation before HCT should be considered in all patients who undergo HCT. Follow-up evaluations should be considered according to clinical signs and symptoms and risk factors. Better preventive strategies and treatments remain to be investigated for individual ocular complications after HCT. Both transplantation physicians and ophthalmologists should be knowledgeable about nonGVHD ocular complications and provide comprehensive collaborative team care. (C) 2018 American Society for Blood and Marrow Transplantation.
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13. |
- Inamoto, Y., et al.
(author)
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Non-GVHD ocular complications after hematopoietic cell transplantation: expert review from the Late Effects and Quality of Life Working Committee of the CIBMTR and Transplant Complications Working Party of the EBMT
- 2019
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In: Bone Marrow Transplantation. - : Springer Science and Business Media LLC. - 0268-3369 .- 1476-5365. ; 54:5, s. 648-661
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Journal article (peer-reviewed)abstract
- Non-graft-vs.-host disease (non-GVHD) ocular complications are generally uncommon after hematopoietic cell transplantation (HCT), but can cause prolonged morbidity affecting activities of daily living and quality of life. Here we provide an expert review of non-GVHD ocular complications in a collaboration between transplant physicians and ophthalmologists through the Late Effects and Quality of Life Working Committee of the Center for International Blood and Marrow Transplant Research and the Transplant Complications Working Party of the European Society of Blood and Marrow Transplantation. Complications discussed in this review include cataracts, glaucoma, ocular infections, ocular involvement with malignancy, ischemic microvascular retinopathy, central retinal vein occlusion, retinal hemorrhage, retinal detachment, and ocular toxicities associated with medications. We have summarized incidence, risk factors, screening, prevention and treatment of individual complicastions and generated evidence-based recommendations. Baseline ocular evaluation before HCT should be considered in all patients who undergo HCT. Follow-up evaluations should be considered according to clinical symptoms, signs and risk factors. Better preventive strategies and treatments remain to be investigated for individual ocular complications after HCT. Both transplant physicians and ophthalmologists should be knowledgeable of non-GVHD ocular complications and provide comprehensive collaborative team care.
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16. |
- McClune, Brian L., et al.
(author)
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Allotransplantation for Patients Age >= 40 Years with Non-Hodgkin Lymphoma : Encouraging Progression-Free Survival
- 2014
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In: Biology of blood and marrow transplantation. - : Elsevier BV. - 1083-8791 .- 1523-6536. ; 20:7, s. 960-968
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Journal article (peer-reviewed)abstract
- Non-Hodgkin lymphoma (NHL) disproportionately affects older patients, who do not often undergo allogeneic hematopoietic cell transplantation (HCT). We analyzed Center for International Blood and Marrow Transplant Research data on 1248 patients age >= 40 years receiving reduced-intensity conditioning (RIC) or nonmyeloablative (NMA) conditioning HCT for aggressive (n = 668) or indolent (n = 580) NHL Aggressive lymphoma was more frequent in the oldest cohort 49% for age 40 to 54 versus 57% for age 55 to 64 versus 67% for age >= 65; P = .0008). Fewer patients aged >= 65 had previous autografting (26% versus 24% versus 9%; P = .002). Rates of relapse, acute and chronic GVHD, and nonrelapse mortality (NRM) at 1 year post-HCT were similar in the 3 age cohorts (22% [95% confidence interval (CI), 19% to 26%] for age 40 to 54, 27% [95% CI, 23% to 31%] for age 55 to 64, and 34% [95% CI, 24% to 44%] for age >= 65. Progression-free survival (PFS) and overall survival (OS) at 3 years was slightly lower in the older cohorts (OS: 54% [95% CI, 50% to 58%] for age 40 to 54; 40% [95% CI, 36% to 44%] for age 55 to 64, and 39% [95% CI, 28% to 50%] for age >= 65; P < .0001). Multivariate analysis revealed no significant effect of age on the incidence of acute or chronic GVHD or relapse. Age >= 55 years, Karnofsky Performance Status <80, and HLA mismatch adversely affected NRM, PFS, and OS. Disease status at HCT, but not histological subtype, was associated with worse NRM, relapse, PFS, and OS. Even for patients age >= 55 years, OS still approached 40% at 3 years, suggesting that HCT affects long-term remission and remains underused in qualified older patients with NHL.
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17. |
- Emmoth, Birger, et al.
(author)
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In-situ measurements of carbon and deuterium deposition using the fast reciprocating probe in TEXTOR
- 2009
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In: Journal of Nuclear Materials. - : Elsevier BV. - 0022-3115 .- 1873-4820. ; 390-91, s. 179-182
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Journal article (peer-reviewed)abstract
- Silicon samples were exposed in the scrape-off layer of the TEXTOR plasma using a fast reciprocating probe, with the aim of studying carbon deposition and deuterium retention during Dynamic Ergodic Divertor (DED) operation. Separate samples were exposed for 300 ms at the flat-top phase of neutral beam heated discharges. The exposure conditions were varied on a shot-to-shot basis by external magnetic perturbations generated by the DED in the m/n = 3/1, DC regime, base configuration. Nuclear Reaction Analysis (NRA) was used to characterise collector sample surfaces after their exposure. Enhanced concentrations of both carbon and deuterium (C 3-10 x 10(16) at./cm(2), D 8-60 x 10(15) at./cm(2)) were found. The D/C ratio was less than unity which indicates that most of the carbon and deuterium were co-deposited. Carbon e-folding lengths of about 2 cm were found on both toroidal sides of the probe independent of DED perturbations.
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18. |
- Jacoby, Nori, et al.
(author)
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Commonality and variation in mental representations of music revealed by a cross-cultural comparison of rhythm priors in 15 countries
- 2024
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In: Nature Human Behaviour. - : Springer Nature. - 2397-3374. ; 8:5, s. 846-877
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Journal article (peer-reviewed)abstract
- Music is present in every known society but varies from place to place. What, if anything, is universal to music cognition? We measured a signature of mental representations of rhythm in 39 participant groups in 15 countries, spanning urban societies and Indigenous populations. Listeners reproduced random ‘seed’ rhythms; their reproductions were fed back as the stimulus (as in the game of ‘telephone’), such that their biases (the prior) could be estimated from the distribution of reproductions. Every tested group showed a sparse prior with peaks at integer-ratio rhythms. However, the importance of different integer ratios varied across groups, often reflecting local musical practices. Our results suggest a common feature of music cognition: discrete rhythm ‘categories’ at small-integer ratios. These discrete representations plausibly stabilize musical systems in the face of cultural transmission but interact with culture-specific traditions to yield the diversity that is evident when mental representations are probed across many cultures.
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20. |
- Bien, Jan, et al.
(author)
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Demonstration bridge C: Masonry Arch Structure : Sustainable Bridges Background document 7.4
- 2007
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Reports (peer-reviewed)abstract
- The bridge was selected as a typical masonry arch bridge for demonstration and testing of the project achievements. The age (built 1875), construction and span length (arch radius 4,97 m) of the structure are representative for masonry bridges in Europe. The bridge also doesn't have any technical documentation as most of old masonry bridges. From the practical point of view it is interesting that the track in service is placed asymmetrically, just on one side of the bridge.Within the works performed on the bridge the following activities can be distinguished:• NDT testing of the structure geometry and material in situ,• Laboratory test of specimens taken form the structure,• Numerical analyses for evaluation of the bridge load capacity and the ultimate load.
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21. |
- Braun, Oscar, et al.
(author)
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Enhanced active metabolite generation and platelet inhibition with prasugrel compared to clopidogrel regardless of genotype in thienopyridine metabolic pathways
- 2013
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In: Thrombosis and Haemostasis. - 0340-6245 .- 2567-689X. ; 110:6, s. 1223-1231
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Journal article (peer-reviewed)abstract
- Clopidogrel response varies according to the presence of genetic polymorphisms. The CYP2C19*2 allele has been associated with impaired response; conflicting results have been reported for CYP2C19*17, ABCB1, and PON1 genotypes. We assessed the impact of CYP2C19, PON1, and ABCB1 polymorphisms on clopidogrel and prasugrel pharmacodynamic (PD) and pharmacokinetic (PK) parameters. Aspirin-treated patients (N=194) with coronary artery disease from two independent, prospective, randomised, multi-centre studies comparing clopidogrel (75 mg) and prasugrel (10 mg) were genotyped and classified by predicted CYP2C19 metaboliser phenotype (ultra metabolisers [UM] = *17 carriers; extensive metabolisers [EM] = *1/1 homozygotes; reduced metabolisers [RM] = *2 carriers). ABCB1 T/T and C/T polymorphisms and PON1 A/A, A/G and G/G polymorphisms were also genotyped. PD parameters were assessed using VerifyNow (R) P2Y12 and vasodilator stimulated phosphoprotein (VASP) expressed as platelet reactivity index (PR!) after 14 days of maintenance dosing. Clopi-, dogrel and prasugrel active metabolite (AM) exposure was calculated in a cohort of 96 patients. For clopidogrel, genetic variants in CYP2C19, but notABCB1 or PON1, affected PK and PD. For prasugrel, none of the measured genetic variants affected PK or PD. Compared with clopidogrel, platelet inhibition with prasugrel was greater even in the CYP2C19 UM phenotype. Prasugrel generated more AM and achieved greater platelet inhibition than clopidogrel irrespective of CYP2C19, ABCB1, and PON1 polymorphisms. The lack of effect from genetic variants on prasugrel AM generation or antiplatelet activity is consistent with previous studies in healthy volunteers and is consistent with improved efficacy in acute coronary syndrome patients managed with percutaneous coronary intervention.
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22. |
- Erlinge, David, et al.
(author)
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Prasugrel 5-mg in the very elderly attenuates platelet inhibition but maintains non-inferiority to prasugrel 10-mg in non-elderly patients: The GENERATIONS trial, a pharmacodynamic and pharmacokinetic study in stable coronary artery disease patients.
- 2013
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In: Journal of the American College of Cardiology. - : Elsevier BV. - 0735-1097. ; 62:7, s. 577-583
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Journal article (peer-reviewed)abstract
- OBJECTIVES: We assessed pharmacodynamic (PD) response for the reduced prasugrel 5-mg maintenance dose in very elderly (≥75y; VE) patients. BACKGROUND: In TRITON-TIMI 38, prasugrel 10-mg reduced ischemic events versus clopidogrel 75-mg, but increased bleeding in VE patients. METHODS: We examined PD and active-metabolite pharmacokinetics with prasugrel 5-mg and 10-mg and clopidogrel 75-mg in a three-period (12 days each), blinded, cross-over study in VE (n=73, mean 79±3y) or non-elderly (≥45-<65y, NE) (n=82, 56±5y) stable coronary artery disease (CAD) patients on background aspirin. Assays included light transmission aggregometry (LTA), VerifyNow(®) P2Y12 (VN-P2Y12), and VASP. The primary comparison was non-inferiority of maximum platelet aggregation (MPA) comparing the median for prasugrel 5-mg in VE versus the 75th percentile for prasugrel 10-mg in NE, using a prespecified one-sided 97.5% confidence interval for the difference <15%. RESULTS: Prasugrel 5-mg in VE met the primary pharmacodynamic non-inferiority criterion versus prasugrel 10-mg in NE. For prasugrel 5-mg, MPA was significantly lower (mean±SD, 57±14%) than clopidogrel (63±14%) (p<0.001) in VE, but higher than prasugrel 10-mg in NE (46±12%) (p<0.001). PD response by LTA, VN-P2Y12, and VASP during all treatments appeared similar between age cohorts. Prasugrel 5-mg resulted in fewer VE poor responders versus clopidogrel. Rates of mild bleeding were higher with prasugrel 10-mg, but similar for prasugrel 5-mg versus clopidogrel 75-mg. CONCLUSIONS: In aspirin-treated stable CAD patients, prasugrel 5-mg in VE attenuated platelet inhibition while meeting prespecified non-inferiority criterion versus prasugrel 10-mg in NE, with significantly better PD response and fewer poor responders compared to clopidogrel 75-mg in VE.
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23. |
- Erlinge, David, et al.
(author)
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Prasugrel 5 mg in the Very Elderly Attenuates Platelet Inhibition But Maintains Noninferiority to Prasugrel 10 mg in Nonelderly Patients
- 2013
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In: Journal of the American College of Cardiology. - : Elsevier. - 0735-1097 .- 1558-3597. ; 62:7, s. 577-583
-
Journal article (peer-reviewed)abstract
- Objectives This study assessed pharmacodynamic (PD) response to the reduced prasugrel maintenance dose of 5 mg in very elderly (VE) patients (andgt;= 75 years of age). less thanbrgreater than less thanbrgreater thanBackground In the TRITON-TIMI 38 (TRial to Assess Improvement in Therapeutic Outcomes by Optimizing Platelet InhibitioN with Prasugrel-Thrombolysis In Myocardial Infarction 38) study prasugrel 10 mg reduced ischemic events versus clopidogrel 75 mg, but increased bleeding in VE patients. less thanbrgreater than less thanbrgreater thanMethods We examined PD and active metabolite pharmacokinetics (PKs) with prasugrel 5 and 10 mg and clopidogrel 75 mg in a 3-period (12 days each) blinded, crossover study in VE (n = 73; mean: 79 +/- 3 years of age) or (n 82) nonelderly (NE) (andgt;= 45 to andlt;65 years of age; mean: 56 +/- 5 years of age) stable coronary artery disease (CAD) patients receiving background aspirin. Assays included light transmission aggregometry (LTA), VerifyNow P2Y12 (VN-P2Y12), and vasodilator-associated stimulated phosphoprotein (VASP). The primary comparison was noninferiority of maximum platelet aggregation (MPA) comparing the median for prasugrel 5 mg in VE versus the 75th percentile for prasugrel 10 mg in NE, using a pre-specified 1-sided 97.5% confidence interval for the difference andlt;15%. less thanbrgreater than less thanbrgreater thanResults Prasugrel 5 mg in VE met the primary PD noninferiority criterion versus prasugrel 10 mg in NE. For prasugrel 5 mg, MPA was significantly lower (57 +/- 14%) than clopidogrel (63 +/- 14%; p andlt; 0.001) in VE but higher than prasugrel 10 mg in NE (46 +/- 12%; p andlt; 0.001). PD response by LTA, VN-P2Y12, and VASP during all treatments appeared similar between age cohorts. Prasugrel 5 mg resulted in fewer VE poor responders than clopidogrel. Rates of mild bleeding were higher with prasugrel 10 mg but similar for prasugrel 5 mg versus clopidogrel 75 mg. less thanbrgreater than less thanbrgreater thanConclusions In aspirin-treated stable CAD patients, prasugrel 5 mg in VE attenuated platelet inhibition while meeting pre-specified noninferiority criterion versus prasugrel 10 mg in NE, with significantly better PD response and fewer poor responders compared to clopidogrel 75 mg in VE. (Comparison of Prasugrel and Clopidogrel in Very Elderly and Non-Elderly Patients With Stable Coronary Artery Disease [GENERATIONS]; NCT01107912)
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25. |
- Gurbel, Paul A., et al.
(author)
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The effect of CYP2C19 gene polymorphisms on the pharmacokinetics and pharmacodynamics of prasugrel 5-mg, prasugrel 10-mg and clopidogrel 75-mg in patients with coronary artery disease
- 2014
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In: Thrombosis and Haemostasis. - : Schattauer. - 0340-6245 .- 2567-689X. ; 112:3, s. 589-597
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Journal article (peer-reviewed)abstract
- CYP2C19 genotype has been shown to impact response to clopidogrel 75-mg but not prasugrel 10-mg. Here, we assessed effects of CYP2C19 metaboliser status on pharmacokinetics (PK) and pharmacodynamic (PD) responses to prasugrel 5-mg and 10-mg and clopidogrel 75-mg using data from two PK/PD studies in stable coronary artery disease (CAD) patients (GENERATIONS and FEATHER). Active metabolite concentrations (area under the curve, AUC([0-tlast])), maximum platelet aggregation (MPA) measured by light transmission aggregometry, vasodilator-stimulated phosphoprotein platelet reactivity index, and VerifyNow P2Y12-platelet reaction units (VN-PRU) were analysed by CYP2C19-predicted phenotype (extensive metaboliser [EM; N=154], *2-*8 non-carriers, vs reduced metaboliser [RM; N=41],*2-*8 carriers/*17 non-carriers). AUC((0-tlast)) was unaffected by metaboliser status for prasugrel 5-mg and 10-mg (geometric mean EM/RM ratios 1.00, 95% confidence interval [Cl]: 0.86,1.17, p>0.99; and 0.97, 95% CI:0.85,1.12, p=0.71, respectively), but was lower among RMs receiving clopidogrel 75-mg (1.37, 95% CI:1.14,1.65, p<0.001). Platelet reactivity was not significantly affected by CYP2C19 metaboliser status for prasugrel 5-mg, or for prasugrel 10-mg by MPA and VN-PRU, but for clopidogrel 75-mg was significantly higher in reduced metabolisers (all measures p<0.01). Prasugrel 10-mg showed greater antiplatelet effects vs clopidogrel 75-mg (all comparisons p<0.001). Prasugrel 5-mg showed greater antiplatelet effects vs clopidogrel 75-mg in RMs (all p<0.001), and comparable effects in EMs (all p >= 0.37). In contrast to clopidogrel, prasugrel active metabolite PK was not influenced by CYP2C19 genotype. Antiplatelet effect for prasugrel 10-mg was greater irrespective of metaboliser status and for prasugrel 5-mg was greater for RMs and comparable for EMs as compared to clopidogrel 75-mg.
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26. |
- Jakubowski, Joseph A., et al.
(author)
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The influence of body size on the pharmacodynamic and pharmacokinetic response to clopidogrel and prasugrel : A retrospective analysis of the FEATHER study
- 2014
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In: Thrombosis Research. - : Elsevier BV. - 0049-3848 .- 1879-2472. ; 134:3, s. 552-557
-
Journal article (peer-reviewed)abstract
- Introduction: Patients treated with clopidogrel who have higher body size exhibit greater platelet reactivity than patients with lower body size. In a retrospective analysis of the FEATHER trial, we examined the relationship between platelet response to thienopyridines clopidogrel 75 mg (Clop-75), prasugrel 5 mg (Pras-5), and prasugrel 10 mg (Pras-10) using 3 body size indices: body weight (BW), body mass index (BMI), and body surface area (BSA). Relationships were assessed as continuous variables and as 4 incremental body size groups. Materials and Methods: Aspirin-treated patients with stable coronary artery disease (N = 72) and a BW range of 45-134 kg received Clop-75, Pras-5, and Pras-10 in a 3-period, blinded, cross-over study. Platelet assays included maximum platelet aggregation (MPA) to 20 mu M ADP by light transmission aggregometry, VerifyNow-P2Y12 reaction units (PRU), and vasodilator-associated stimulated phosphoprotein (VASP) phosphorylation platelet reactivity index (PRI). Exposure to active metabolites (AMs) was also assessed. Results: Body size was a determinant of AM exposure and residual platelet reactivity regardless of type and dose of thienopyridine. BW and BSA demonstrated marginally stronger correlations with platelet reactivity; VASP-PRI demonstrated a stronger correlation with the body size than the other tests. Correlation coefficients ranged from a high of 0.64 (BW vs. PRI on Pras-5) to a low of 0.34 (BMI vs. MPA on Pras-10), but all were statistically significant (p < 0.01). Conclusions: Using a comprehensive selection of body size indices, AM exposures, platelet function tests, and thienopyridine doses, we demonstrated a consistent inverse relationship between body size and response to clopidogrel and prasugrel. (C) 2014 Elsevier Ltd. All rights reserved.
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28. |
- Judge, H M, et al.
(author)
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Potentiation of clopidogrel active metabolite formation by rifampicin leads to greater P2Y12 receptor blockade and inhibition of platelet aggregation after clopidogrel.
- 2010
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In: Journal of Thrombosis and Haemostasis. - : Elsevier BV. - 1538-7933 .- 1538-7836. ; 8:8
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Journal article (peer-reviewed)abstract
- BACKGROUND: The thienopyridine P2Y(12) receptor antagonist clopidogrel reduces the risk of arterial thrombosis and individual pharmacodynamic responses to clopidogrel are believed to reflect the levels of active metabolite (AM) generated. Rifampicin increases the inhibitory effect of clopidogrel on platelet aggregation (PA). We studied the response to clopidogrel before and during administration of rifampicin in order to study the relationship between individual AM levels and P2Y(12) blockade.METHODS: Healthy volunteers received a 600-mg loading dose of clopidogrel followed by 75 mg daily for 7 days and, after a washout period and treatment with rifampicin [300 mg twice a day (b.i.d.)], received the same regimen of clopidogrel. Clopidogrel AM levels were determined over 4 h after the clopidogrel loading dose and unblocked P2Y(12) receptor number was assessed using a (33) P-2MeSADP binding assay. PA was measured by optical aggregometry with ADP and TRAP.RESULTS: Rifampicin enhanced clopidogrel AM production [area-under-the-curve (AUC): clopidogrel 89±22 ng h mL(-1) , clopidogrel+rifampicin 335±86 ng h mL(-1) , P<0.0001], and P2Y(12) blockade (unblocked receptors: clopidogrel 48±24, clopidogrel+rifampicin 4±2, P<0.0001) and reduced PA (5 μmol L(-1) ADP: clopidogrel 20±4, clopidogrel+rifampicin 5±2, P<0.01). Increasing numbers of unblocked receptors were required for an aggregation response with a decreasing concentration of ADP. PA induced by ADP 2 μmol L(-1) was particularly sensitive to low levels of receptor blockade.CONCLUSION: Potentiation of clopidogrel AM production by rifampicin leads to greater P2Y(12) blockade and consequently greater inhibition of PA. PA responses to low concentrations of ADP are more sensitive to P2Y(12) blockade.
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29. |
- Judge, Heather M, et al.
(author)
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Relationship between degree of P2Y12 receptor blockade and inhibition of P2Y12-mediated platelet function.
- 2010
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In: Thrombosis and Haemostasis. - 0340-6245 .- 2567-689X. ; 103:6
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Journal article (peer-reviewed)abstract
- The thienopyridine P2Y12 receptor antagonists clopidogrel and prasugrel prevent arterial thrombosis and are routinely used following percutaneous coronary intervention. However, the optimal level of P2Y12 blockade to effectively inhibit platelet function is unknown. These studies utilised the active metabolite of prasugrel (R-138727) to achieve a range of P2Y12 blockade in vitro and assessed several aspects of platelet function. Blood from healthy volunteers was incubated with R-138727 (0-10 microM). P2Y12 receptor number was assessed using a 33P-2MeSADP binding assay. Platelet aggregation (PA) was measured by optical aggregometry with ADP 2-20 microM. VASP phosphorylation, annexin V binding, microparticle formation and P-selectin expression were assessed by flow cytometry. Increasing numbers of unblocked receptors were required for a sustained aggregation response with decreasing concentrations of ADP. A P2Y12 receptor blockade of 60-80% resulted in strong inhibition of final PA response, P-selectin expression, microparticle formation and vasodilator-stimulated phosphoprotein (VASP). PA induced by ADP 2 microM and P-selectin expression were particularly sensitive to low levels of receptor blockade whereas the VASP phosphorylation assay was relatively insensitive, requiring 60% receptor blockade to achieve substantial inhibition. Different assays varied in their ability to discriminate particular ranges of P2Y12 blockade and 80% or greater P2Y12 receptor blockade is required for consistently strong inhibition of several aspects of platelet function. These data guide the interpretation of results from different assays used to monitor the effects of P2Y12 receptor antagonists.
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30. |
- Judge, Heather M, et al.
(author)
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The active metabolite of prasugrel effectively blocks the platelet P2Y12 receptor and inhibits procoagulant and pro-inflammatory platelet responses.
- 2008
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In: Platelets. - : Informa UK Limited. - 0953-7104 .- 1369-1635. ; 19:2
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Journal article (peer-reviewed)abstract
- The aim of these studies was to investigate the extent of platelet P2Y(12) receptor inhibition by the thienopyridine active metabolite of prasugrel, R-138727. Blood was taken from healthy volunteers and pre-incubated with R-138727 or cangrelor (AR-C66931MX). Platelet aggregation was assessed in platelet rich plasma (PRP) and whole blood (WB). Vasodilator stimulated phosphoprotein (VASP) phosphorylation, platelet procoagulant activity (annexin V binding and microparticle formation) and calcium mobilisation were measured by flow cytometry. Platelet-leukocyte co-aggregate formation and sCD40L release, both pro-inflammatory responses of platelets, were measured by flow cytometry and ELISA, respectively. P2Y(12) receptor antagonism was determined using a radioligand binding assay ((33)P 2-MeSADP) in resting and stimulated platelets and the effects of clopidogrel administration were also assessed. R-138727 yielded concentration-dependent inhibition of platelet aggregation, VASP phosphorylation inhibition, procoagulant activity and pro-inflammatory responses. In the presence of R-138727 or cangrelor there was increased calcium reuptake following agonist stimulation. R-138727 30 micromol/L and cangrelor 1 micromol/L completely inhibited (33)P 2-MeSADP binding, compared to partial inhibition following clopidogrel administration. Platelet activation and granule secretion did not expose an additional pool of P2Y(12) receptors. Prasugrel's active metabolite effectively blocks the P2Y(12) receptor with the highest concentrations tested yielding complete inhibition of P2Y(12)-mediated amplification of several important platelet responses.
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31. |
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32. |
- Wagner, Henrik, et al.
(author)
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Higher body weight patients on clopidogrel maintenance therapy have lower active metabolite concentrations, lower levels of platelet inhibition, and higher rates of poor responders than low body weight patients
- 2014
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In: Journal of Thrombosis and Thrombolysis. - : Springer Science and Business Media LLC. - 0929-5305 .- 1573-742X. ; 38:2, s. 127-136
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Journal article (peer-reviewed)abstract
- Body weight is a predictor of clopidogrel response. However, no prospective studies have compared pharmacodynamic (PD) and pharmacokinetic (PK) data based on body weight. We compared PD and PK effects of clopidogrel 75 mg in low body weight (LBW, <60 kg) and higher body weight (HBW, >= 60 kg) patients with stable coronary artery disease. LBW (n = 34, 56.4 +/- 3.7 kg) and HBW (n = 38, 84.7 +/- 14.9 kg) aspirin-treated patients received clopidogrel 75 mg for 10-14 days. The area under the concentration-time curve of active metabolite (Clop-AM) calculated through the last quantifiable concentration up to 4 h postdose, AUC((0-tlast)), was calculated by non-compartmental methods. Light transmission aggregometry (LTA) (maximum platelet aggregation and inhibition of platelet aggregation to 20 mu M adenosine diphosphate (ADP), and residual platelet aggregation to 5 mu M ADP), VerifyNow (R) P2Y12 reaction units (PRU), and vasodilator-associated stimulated phosphoprotein phosphorylation platelet reactivity index (VASP-PRI) were performed. Mean AUC((0-tlast)) was lower in HBW than LBW patients: 12.8 versus 17.9 ng h/mL. HBW patients had higher platelet reactivity as measured by LTA (all p <= 0.01), PRU (207 +/- 68 vs. 152 +/- 57, p < 0.001), and VASP-PRI (56 +/- 18 vs. 39 +/- 17, p < 0.001). More HBW patients exhibited high on-treatment platelet reactivity (HPR) using PRU (35 vs. 9 %) and VASP-PRI (65 vs. 27 %). Body weight correlated with PRU and VASP-PRI (both p < 0.001), and inversely with log transformed AUC((0-tlast)) (p < 0.001). In conclusion, HBW patients had lower levels of Clop-AM, and higher platelet reactivity and rates of HPR than LBW subjects, contributing to their suboptimal response to clopidogrel.
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