| 1. |
- Postmus, Iris, et al.
(författare)
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Pharmacogenetic meta-analysis of genome-wide association studies of LDL cholesterol response to statins.
- 2014
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Ingår i: Nature communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 5
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Tidskriftsartikel (refereegranskat)abstract
- Statins effectively lower LDL cholesterol levels in large studies and the observed interindividual response variability may be partially explained by genetic variation. Here we perform a pharmacogenetic meta-analysis of genome-wide association studies (GWAS) in studies addressing the LDL cholesterol response to statins, including up to 18,596 statin-treated subjects. We validate the most promising signals in a further 22,318 statin recipients and identify two loci, SORT1/CELSR2/PSRC1 and SLCO1B1, not previously identified in GWAS. Moreover, we confirm the previously described associations with APOE and LPA. Our findings advance the understanding of the pharmacogenetic architecture of statin response.
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| 2. |
- Van Eunen, K., et al.
(författare)
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Measuring enzyme activities under standardized in-vivo like conditions for systems biology
- 2010
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Ingår i: FEBS Journal. - : Wiley. - 1742-4658 .- 1742-464X. ; 277:3, s. 749-760
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Tidskriftsartikel (refereegranskat)abstract
- Realistic quantitative models require data from many laboratories. Therefore, standardization of experimental systems and assay conditions is crucial. Moreover, standards should be representative of the in vivo conditions. However, most often, enzyme-kinetic parameters are measured under assay conditions that yield the maximum activity of each enzyme. In practice, this means that the kinetic parameters of different enzymes are measured in different buffers, at different pH values, with different ionic strengths, etc. In a joint effort of the Dutch Vertical Genomics Consortium, the European Yeast Systems Biology Network and the Standards for Reporting Enzymology Data Commission, we have developed a single assay medium for determining enzyme-kinetic parameters in yeast. The medium is as close as possible to the in vivo situation for the yeast Saccharomyces cerevisiae, and at the same time is experimentally feasible. The in vivo conditions were estimated for S. cerevisiae strain CEN. PK113-7D grown in aerobic glucose-limited chemostat cultures at an extracellular pH of 5.0 and a specific growth rate of 0.1 h(-1). The cytosolic pH and concentrations of calcium, sodium, potassium, phosphorus, sulfur and magnesium were determined. On the basis of these data and literature data, we propose a defined in vivo-like medium containing 300 mm potassium, 50 mm phosphate, 245 mm glutamate, 20 mm sodium, 2 mm free magnesium and 0.5 mm calcium, at a pH of 6.8. The V(max) values of the glycolytic and fermentative enzymes of S. cerevisiae were measured in the new medium. For some enzymes, the results deviated conspicuously from those of assays done under enzyme-specific, optimal conditions
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| 3. |
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| 4. |
- van der Veldt, Astrid A. M., et al.
(författare)
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Toward Prediction of Efficacy of Chemotherapy : A Proof of Concept Study in Lung Cancer Patients Using [11C]docetaxel and Positron Emission Tomography
- 2013
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Ingår i: Clinical Cancer Research. - 1078-0432 .- 1557-3265. ; 19:15, s. 4163-4173
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Tidskriftsartikel (refereegranskat)abstract
- Purpose:Pharmacokinetics of docetaxel can be measured in vivo using positron emission tomography (PET) and a microdose of radiolabeled docetaxel ([11C]docetaxel). The objective of this study was to investigate whether a [11C]docetaxel PET microdosing study could predict tumor uptake of therapeutic doses of docetaxel.Experimental Design:Docetaxel-naïve lung cancer patients underwent 2 [11C]docetaxel PET scans; one after bolus injection of [11C]docetaxel and another during combined infusion of [11C]docetaxel and a therapeutic dose of docetaxel (75 mg·m−2). Compartmental and spectral analyses were used to quantify [11C]docetaxel tumor kinetics. [11C]docetaxel PET measurements were used to estimate the area under the curve (AUC) of docetaxel in tumors. Tumor response was evaluated using computed tomography scans.Results:Net rates of influx (Ki) of [11C]docetaxel in tumors were comparable during microdosing and therapeutic scans. [11C]docetaxel AUCTumor during the therapeutic scan could be predicted reliably using an impulse response function derived from the microdosing scan together with the plasma curve of [11C]docetaxel during the therapeutic scan. At 90 minutes, the accumulated amount of docetaxel in tumors was less than 1% of the total infused dose of docetaxel. [11C]docetaxel Ki derived from the microdosing scan correlated with AUCTumor of docetaxel (Spearman ρ = 0.715; P = 0.004) during the therapeutic scan and with tumor response to docetaxel therapy (Spearman ρ = −0.800; P = 0.010).Conclusions:Microdosing data of [11C]docetaxel PET can be used to predict tumor uptake of docetaxel during chemotherapy. The present study provides a framework for investigating the PET microdosing concept for radiolabeled anticancer drugs in patients.
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| 5. |
- de Boer, Rudolf A, et al.
(författare)
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The WAP four-disulfide core domain protein HE4 : a novel biomarker for heart failure.
- 2013
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Ingår i: JACC. Heart failure. - : Elsevier BV. - 2213-1787 .- 2213-1779. ; 1:2, s. 164-169
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: This study investigated clinical determinants and added prognostic value of HE4 as a biomarker not previously described in heart failure (HF).BACKGROUND: Identification of plasma biomarkers that help to risk stratify HF patients may help to improve treatment.METHODS: Plasma HE4 levels were determined in 567 participants of the COACH (Coordinating study evaluating outcomes of Advising and Counseling in Heart failure). Patients had been hospitalized for HF and were followed for 18 months. The primary endpoint of this study was a composite of all-cause mortality and HF hospitalization.RESULTS: HE4 showed a strong correlation with HF severity, according to New York Heart Association functional class and brain natriuretic peptide (BNP) levels (p < 0.001). HE4 also showed a positive correlation with GDF15 (p < 0.001) and, in addition, correlated with kidney function (estimated glomerular filtration rate [eGFR]; p < 0.001). Cox regression analysis revealed that a doubling of HE4 levels was associated with a hazard ratio (HR) of 1.73 (95% confidence interval [CI]: 1.53 to 1.95) for the primary outcome (p < 0.001). After correction for age, gender, BNP, and eGFR, the HR was 1.46 (95% CI: 1.23 to 1.72; p < 0.001), and after additional adjustment for GDF15, the HR lowered to 1.30 (95% CI: 1.07 to 1.59; p = 0.009). The area under the curve in the receiver-operating characteristic curve analysis increased from 0.727 to 0.752 when HE4 was included in the clinical evaluation (p = 0.051). The integrated discrimination improvement and net reclassification index for reclassification showed significant improvements when HE4 was added to the clinical model, and this remained significant after BNP inclusion in the model.CONCLUSIONS: HE4 plasma levels are correlated with markers of HF severity, show prognostic value, and can improve risk assessment in HF.
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| 6. |
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| 7. |
- Nieuwenhuis, Maurice M W, et al.
(författare)
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Long-Term Compliance With Nonpharmacologic Treatment of Patients With Heart Failure
- 2012
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Ingår i: American Journal of Cardiology. - : Elsevier. - 0002-9149 .- 1879-1913. ; 110:3, s. 392-397
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to examine long-term compliance with nonpharmacologic treatment of patients with heart failure (HF) and its associated variables. Data from 648 hospitalized patients with HF (mean age 69 +/- 12 years, 38% women, mean left ventricular ejection fraction 33 +/- 14%) were analyzed. Compliance was assessed by means of self-report at baseline and 1, 6, 12, and 18 months after discharge. Patients completed questionnaires on depressive symptoms, HF knowledge, and physical functioning at baseline. Logistic regression analyses were performed to examine independent associations with low long-term compliance. From baseline to 18-month follow-up, long-term compliance with diet and fluid restriction ranged from 77% to 91% and from 72% to 89%, respectively. In contrast, compliance with daily weighing (34% to 85%) and exercise (48% to 64%) was lower. Patients who were in New York Heart Association functional class II were more often noncompliant with fluid restriction (odds ratio [OR] 1.97, 95% confidence interval [CI] 1.25 to 3.08). A lower level of knowledge on HF was independently associated with low compliance with fluid restriction (OR 0.78, 95% CI 0.71 to 0.86) and daily weighing (OR 0.86, 95% CI 0.79 to 0.94). Educational support improved compliance with these recommendations. Female gender (OR 1.91, 95% CI 1.26 to 2.90), left ventricular ejection fraction andgt;= 40% (OR 1.55, 95% CI 1.03 to 2.34), a history of stroke (OR 3.55, 95% CI 1.54 to 8.16), and less physical functioning (OR 0.99, 95% CI 0.98 to 0.99) were associated with low compliance with exercise. In conclusion, long-term compliance with exercise and daily weighing was lower than long-term compliance with advice on diet and fluid restriction. Although knowledge on HF and being offered educational support positively affected compliance with weighing and fluid restriction, these variables were not related to compliance with exercise. Therefore, new approaches to help patients with HF stay physically active are needed. (C) 2012 Elsevier Inc. All rights reserved. (Am J Cardiol 2012;110:392-397)
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| 8. |
- Postmus, Douwe, et al.
(författare)
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A trial-based economic evaluation of 2 nurse-led disease management programs in heart failure
- 2011
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Ingår i: American Heart Journal. - : Elsevier. - 0002-8703 .- 1097-6744. ; 162:6, s. 1096-1104
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Tidskriftsartikel (refereegranskat)abstract
- Background Although previously conducted meta-analyses suggest that nurse-led disease management programs in heart failure (HF) can improve patient outcomes, uncertainty regarding the cost-effectiveness of such programs remains. Methods To compare the relative merits of 2 variants of a nurse-led disease management program (basic or intensive support by a nurse specialized in the management of patients with HF) against care as usual (routine follow-up by a cardiologist), a trial-based economic evaluation was conducted alongside the COACH study. Results In terms of costs per life-year, basic support was found to dominate care as usual, whereas the incremental cost-effectiveness ratio between intensive support and basic support was found to be equal to (sic)532,762 per life-year; in terms of costs per quality-adjusted life-year (QALY), basic support was found to dominate both care as usual and intensive support. An assessment of the uncertainty surrounding these findings showed that, at a threshold value of (sic)20,000 per life-year/(sic)20,000 per QALY, basic support was found to have a probability of 69/62% of being optimal against 17/30% and 14/8% for care as usual and intensive support, respectively. The results of our subgroup analysis suggest that a stratified approach based on offering basic support to patients with mild to moderate HF and intensive support to patients with severe HF would be optimal if the willingness-to-pay threshold exceeds (sic)45,345 per life-year/(sic)59,289 per QALY. Conclusions Although the differences in costs and effects among the 3 study groups were not statistically significant, from a decision-making perspective, basic support still had a relatively large probability of generating the highest health outcomes at the lowest costs. Our results also substantiated that a stratified approach based on offering basic support to patients with mild to moderate HF and intensive support to patients with severe HF could further improve health outcomes at slightly higher costs.
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| 9. |
- Postmus, Douwe, et al.
(författare)
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The COACH risk engine : a multistate model for predicting survival and hospitalization in patients with heart failure
- 2012
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Ingår i: European Journal of Heart Failure. - : Oxford University Press (OUP): Policy B. - 1388-9842 .- 1879-0844. ; 14:2, s. 168-175
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Tidskriftsartikel (refereegranskat)abstract
- Aims Several models for predicting the prognosis of heart failure (HF) patients have been developed, but all of them focus on a single outcome variable, such as all-cause mortality. The purpose of this study was to develop a multistate model for simultaneously predicting survival and HF-related hospitalization in patients discharged alive from hospital after recovery from acute HF. less thanbrgreater than less thanbrgreater thanMethods and results The model was derived in the COACH (Coordinating Study Evaluating Outcomes of Advising and Counseling in Heart Failure) cohort, a multicentre, randomized controlled trial in which 1023 patients were enrolled after hospitalization because of HF. External validation was attained with the FINN-AKVA (Finish Acute Heart Failure Study) cohort, a prospective, multicentre study with 620 patients hospitalized due to acute HF. The observed vs. predicted 18-month survival was 72.1% vs. 72.3% in the derivation cohort and 71.4% vs. 71.2% in the validation cohort. The corresponding values of the c statistic were 0.733 [95% confidence interval (CI) 0.705-0.761] and 0.702 (95% CI 0.663-0.744), respectively. The models accuracy in predicting HF hospitalization was excellent, with predicted values that closely resembled the values observed in the derivation cohort. less thanbrgreater than less thanbrgreater thanConclusion The COACH risk engine accurately predicted survival and various measures of recurrent hospitalization in (acute) HF patients. It may therefore become a valuable tool in improving and personalizing patient care and optimizing the use of scarce healthcare resources.
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| 10. |
- van der Veldt, Astrid A M, et al.
(författare)
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Quantitative Parametric Perfusion Images Using 15O-Labeled Water and a Clinical PET/CT Scanner : test-retest variability in lung cancer
- 2010
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Ingår i: Journal of Nuclear Medicine. - : Society of Nuclear Medicine. - 0161-5505 .- 1535-5667 .- 2159-662X. ; 51:11, s. 1684-1690
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Tidskriftsartikel (refereegranskat)abstract
- Quantification of tumor perfusion using radioactive water (H215O) and PET is a promising method for monitoring treatment with antiangiogenic agents. However, use of dynamic H215O scans together with a fully 3-dimensional clinical PET/CT scanner needs to be validated. The purpose of the present study was to assess validity and reproducibility of dynamic H215O PET/CT scans for measuring tumor perfusion and validate the quantitative accuracy of parametric perfusion images.Methods:Eleven patients with non–small cell lung cancer were included in this study. Patients underwent 2 dynamic H215O (370 MBq) PET scans on the same day. During the first scan, arterial blood was withdrawn continuously. Input functions were derived from blood sampler data and the ascending aorta as seen in the images themselves (image-derived input function [IDIF]). Parametric perfusion images were computed using a basis function implementation of the standard single-tissue-compartment model. Volumes of interest (VOIs) were delineated on low-dose CT (LD-CT) and parametric perfusion images.Results:VOIs could be accurately delineated on both LD-CT and parametric perfusion images. These parametric perfusion images had excellent image quality and quantitative accuracy when compared with perfusion values determined by nonlinear regression. Good correlation between perfusion values derived from the blood sampler input function and IDIF was found (Pearson correlation coefficient, r = 0.964; P < 0.001). Test–retest variability of tumor perfusion was 16% and 20% when delineated on LD-CT and parametric perfusion images, respectively.Conclusion:The use of ascending aorta IDIFs is an accurate alternative to arterial blood sampling for quantification of tumor perfusion. Image quality obtained with a clinical PET/CT scanner enables generation of accurate parametric perfusion images. VOIs delineated on LD-CT have the highest reproducibility, and changes of more than 16% in tumor perfusion are likely to represent treatment effects.
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| 11. |
- van der Veldt, Astrid A. M., et al.
(författare)
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Rapid Decrease in Delivery of Chemotherapy to Tumors after Anti-VEGF Therapy : Implications for Scheduling of Anti-Angiogenic Drugs
- 2012
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Ingår i: Cancer Cell. - : Elsevier BV. - 1535-6108 .- 1878-3686. ; 21:1, s. 82-91
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Tidskriftsartikel (refereegranskat)abstract
- Current strategies combining anti-angiogenic drugs with chemotherapy provide clinical benefit in cancer patients. It is assumed that anti-angiogenic drugs, such as bevacizumab, transiently normalize abnormal tumor vasculature and contribute to improved delivery of subsequent chemotherapy. To investigate this concept, a study was performed in non-small cell lung cancer (NSCLC) patients using positron emission tomography (PET) and radiolabeled docetaxel ([11C]docetaxel). In NSCLC, bevacizumab reduced both perfusion and net influx rate of [11C]docetaxel within 5 hr. These effects persisted after 4 days. The clinical relevance of these findings is notable, as there was no evidence for a substantial improvement in drug delivery to tumors. These findings highlight the importance of drug scheduling and advocate further studies to optimize scheduling of anti-angiogenic drugs.
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| 12. |
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