http://repub.eur.nl/res/aut/11137/ List of Publications en http://repub.eur.nl/static-eur/img/logo.png http://repub.eur.nl http://repub.eur.nl/res/pub/17108/ 2009-08-05T00:00:00Z Background: Concentrations of inflammatory and hemostatic variables are influenced by biological variation, which is the natural within-subject variation over time. Objectives: The aim of this study was to determine fibrinogen, C-reactive protein (CRP), platelet aggregation, thrombin generation and prothrombin time (PT): (i) the number of repeated measurements needed to obtain the true habitual concentration of an individual; (ii) the recommended analytical imprecision for diagnosis and monitoring; (iii) the recommended analytical bias; (iv) the contribution of analytical imprecision to test result variability; (v) the index of individuality; (vi) the reference change value; and (vii) the seasonal variation. Subjects and methods: We collected 520 blood samples over a 1-year period from 40 healthy individuals, and determined the between-subject, within-subject and seasonal variation in fibrinogen, CRP, platelet aggregation, thrombin generation and PT. Results: One or two repeated measurements were sufficient to establish the true habitual concentration, except for platelet aggregation and peak thrombin generation, where at least four and nine repeated measurements were needed, respectively. For diagnosis, the maximal recommended coefficient of analytical variation (CV) was 4%-27%, except for CRP (77.7%). For monitoring, these CVs were on average 3% lower. Recommended analytical bias varied between 1.7% and 33.2%. Finally, seasonal variation was observed in concentrations of fibrinogen and thrombin generation, which could explain approximately 11% of their total variation. Conclusion: This study provides insights into the biological variability of selected inflammatory and hemostatic markers, which can be used for sample size calculations and to determine the analytical quality specifications for their respective assays. http://repub.eur.nl/res/pub/29043/ 2008-12-01T00:00:00Z Ischemic stroke is associated with leucocyte activation. Activated leucocytes release elastase, an enzyme that can degrade fibrinogen. Fibrinogen elastase degradation products (FgEDP) may serve as a specific marker of elastase proteolytic activity. In a case-control study of 111 ischemic stroke patients and 119 controls, significantly higher FgEDP levels were observed in cases than in controls, both in the acute phase and in the convalescent phase. Results were only slightly affected by adjustment for cardiovascular risk factors, C-reactive protein and fibrinogen. Our findings suggest that FgEDP might be involved in the pathogenesis of stroke. http://repub.eur.nl/res/pub/14542/ 2008-01-01T00:00:00Z The PERTINENT study measured biomarkers of atherosclerosis and thrombosis in a stable coronary artery disease population from EUROPA receiving ACE inhibition with perindopril 8 mg/day or placebo. Biomarkers of inflammation, C-reactive protein (CRP), fibrinogen, and tumor necrosis factor-alpha (TNF-α), and a biomarker of thrombosis, d-dimer, were measured at baseline and 1 year. CRP was recorded in 1157 patients; fibrinogen, TNF-α, and d-dimer in 291 patients. There was no significant effect of treatment on CRP or fibrinogen. In contrast, there were significant reductions in TNF-α (27.60-25.20 pg/mL; P < 0.05) and d-dimer (0.24-0.18 μg/mL; P < 0.05) with perindopril over 1 year. Survival analysis of the prognostic significance of baseline CRP failed to detect a significant role for the prediction of cardiovascular events over 4 years (lower versus higher tertile: 1.54; 95% confidence interval 0.88-2.68; P = 0.16). In conclusion, in the PERTINENT trial, we observed significant effects of ACE inhibition on biomarkers of the atherothrombotic complications (d-dimer) and the proinflammatory cytokine TNF-α, but not on biomarkers of inflammation associated with atherosclerosis (CRP and fibrinogen). http://repub.eur.nl/res/pub/35656/ 2007-01-01T00:00:00Z Objectives: EUropean trial on Reduction Of cardiac events with Perindopril in stable coronary Artery disease [EUROPA] demonstrates reduction in cardiovascular mortality and myocardial infarction for a possible vascular and antiatherosclerotic effect of angiotensin-converting enzyme (ACE) inhibition with perindopril. Our objective was to study the effect of perindopril on endothelial function and to verify its link to risk and occurrence of cardiovascular events. Methods: Blood from 1200 EUROPA patients was withdrawn at baseline and after 1 year of treatment with either perindopril or placebo to measure von Willebrand factor and from 45 healthy subjects and 87 EUROPA patients to study endothelial function at the cellular level by cultivating in vitro human umbilical vein endothelial cells. In this setting, we determined protein expression/activity of endothelial nitric oxide synthase and the rate of apoptosis. Plasma levels of angiotensin II, bradykinin, tumor necrosis factor α, and nitrite/nitrate were also measured. Results: The occurrence of cardiovascular events was related to von Willebrand factor at baseline (P = 0.013) that also significantly decreased after 1 year's treatment (P < 0.001). Perindopril upregulated 19% and 27% protein expression/activity of endothelial nitric oxide synthase (P < 0.05) as well as reduced the rate of apoptosis by 31% (P < 0.05). There was also a significant reduction in levels of angiotensin II, increase in bradykinin, reduction in tumor necrosis factor α, and increase in nitrite/nitrate (P < 0.05 for all). Conclusions: Abnormal endothelial function occurs in patients with coronary artery disease, and this can be counteracted by angiotensin-converting enzyme inhibition with perindopril. These effects could contribute, at least in part, to explaining the results of the main EUROPA Study. http://repub.eur.nl/res/pub/9146/ 1999-01-01T00:00:00Z BACKGROUND AND PURPOSE: It has been suggested that daily intake of aspirin is associated with a reduction of cognitive decline, both in normal and in demented subjects, but the mechanism is unclear. We have therefore studied the relationship between thromboxane (TX) A(2) biosynthesis, as reflected by the urinary excretion of 11-dehydro-TXB(2), and the presence of dementia in patients after acute stroke. METHODS: Patients from the Rotterdam Stroke Databank were screened for dementia between 3 and 9 months after stroke. Patients had a full neurological examination, neuropsychological screening, and, if indicated, extensive neuropsychological examination. Criteria used for the diagnosis of dementia were from the Diagnostic and Statistical Manual of Mental Disorders, Third Edition (Revised). Urine samples were taken at the time of screening. Urinary 11-dehydro-TXB(2) was measured by means of a previously validated radioimmunoassay. RESULTS: Dementia was diagnosed in 71 patients, and urine samples were available for 62. Median value (range) of 11-dehydro-TXB(2) was 399 (89 to 2105) pmol/mmol creatinine for demented patients versus 273 (80 to 1957) for 69 controls with stroke but without dementia (P=0.013). No difference was found between 44 patients with vascular dementia, 404 (89 to 2105) pmol/mmol creatinine, and 18 patients with Alzheimer's disease plus cerebrovascular disease, 399 (96 to 1467) pmol/mmol creatinine (P=0.68). In a stepwise logistic regression analysis, in which possible confounders such as use of antiplatelet medication, cardiovascular risk factors, and type of stroke were taken into account, increased urinary excretion of 11-dehydro-TXB(2) remained independently related to the presence of dementia (OR 1.12, 95% CI 1.03 to 1.22 per 100 pmol/mmol creatinine). The difference in metabolite excretion rates between demented and nondemented patients was most prominent within the subgroup of ischemic stroke patients who received aspirin (P<0.01). CONCLUSIONS: Increased thromboxane biosynthesis in the chronic phase after stroke is associated with the presence of but not the type of poststroke dementia. It is particularly apparent in patients on aspirin, thereby suggesting the involvement of extraplatelet sources of TXA(2) production in this setting. http://repub.eur.nl/res/pub/8806/ 1998-01-01T00:00:00Z An association between increased plasma fibrinogen and an increased risk for myocardial infarction (MI) is well established, but the nature of this association is subject to debate. Our aim was to shed light on the potentially causal nature of this association. We examined whether increased plasma fibrinogen, due to a condition that is independent of cardiovascular events, also increases the risk for MI. A case-control study was performed in 139 subjects with a history of MI and 287 control subjects selected from the Rotterdam Study, a population-based cohort of 7983 subjects aged 55 years and older. The genotype of the -455G/A polymorphism in the fibrinogen beta-gene was determined by polymerase chain reaction. Functional plasma fibrinogen levels were determined according to von Clauss. The plasma level of fibrinogen was significantly higher in subjects with one or two A alleles compared with subjects with the GG genotype: 3.8 (95% confidence interval [CI], 3.6 to 3.9) g/L and 3.6 (3.5 to 3.7) g/L, respectively. With increasing plasma fibrinogen level, the risk for MI increased gradually; a rise in fibrinogen of 1 g/L was associated with a 45% increased risk (odds ratio adjusted for age, sex, and smoking, 1.45; 95% CI, 1.12 to 1.88). There was no association between the genotype of the -455G/A polymorphism and the risk for MI. The -455G/A polymorphism is therefore associated with increased plasma fibrinogen levels but not with an increased risk for MI. These findings indicate that an increased plasma fibrinogen level due to this genetic factor does not increase the risk for MI. http://repub.eur.nl/res/pub/8905/ 1998-01-01T00:00:00Z BACKGROUND and PURPOSE: Most mental screening tests focus on the detection of cognitive deficits compatible with Alzheimer's disease. Stroke patients who develop a dementia syndrome, however, constitute a more heterogeneous group with both cortical and subcortical disturbances. We assessed the diagnostic accuracy of the CAMCOG (the cognitive and self-contained part of the Cambridge Examination for Mental Disorders of the Elderly) and the Mini-Mental State Examination (MMSE) for dementia in patients with a recent stroke. METHODS: In patients aged 55 and older who were admitted in the Rotterdam Stroke Databank, cognitive functioning was assessed between 3 and 9 months after the most recent stroke. The "gold standard" diagnosis of dementia was compatible with the criteria of the Diagnostic and Statistical Manual of Mental Disorders, Third Edition, Revised. The CAMCOG and MMSE scores were obtained independent of the diagnostic procedure. RESULTS: Of 300 consecutive patients, 71 (23.7%) were demented. Sixteen severely demented patients could not be tested and were excluded. The CAMCOG and MMSE scores were significantly related to dementia (both P<0.0001) in a logistic regression model. Receiver operating characteristic analysis showed that the CAMCOG was a more accurate screening instrument (area under the curve for CAMCOG, 0.95; for MMSE, 0.90). Two other clinical variables independently improved the diagnostic accuracy of the MMSE and CAMCOG: patients with a left hemispheric lesion had a lower (odds ratio, 0.3; 95% confidence interval, 0.1 to 0.7), and patients with hemorrhagic stroke had a greater chance of being demented (odds ratio, 3; 95% confidence interval, 1 to 10). The effect of left hemispheric lesion as an independent diagnostic factor could not be explained by selection or its association with aphasia alone. CONCLUSIONS: The CAMCOG is a feasible instrument for use in patients with a recent transient ischemic attack or stroke. It is a more accurate screening tool for dementia than the MMSE, especially when type and site of stroke are taken into account.