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- Clarke, Robert, et al.
(author)
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Lowering blood homocysteine with folic acid based supplements : Meta-analysis of randomised trials
- 1998
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In: British Medical Journal. - : BMJ. - 0959-8146. ; 316:7135, s. 894-898
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Research review (peer-reviewed)abstract
- Objective: To determine the size of reduction in homocysteine concentrations produced by dietary supplementation with folic acid and with vitamins B-12 or B-6. Design: Meta-analysis of randomised controlled trials that assessed the effects of folic acid based supplements on blood homocysteine concentration. Multivariate regression analysis was used to determine the effects on homocysteine concentrations of different doses of folic acid and of the addition of vitamin B-12 or B-6. Subjects: Individual data on 1114 people included in 12 trials. Findings: The proportional and absolute reductions in blood homocysteine produced by folic acid supplements were greater at higher pretreatment blood homocysteine concentrations (P < 0.001) and at lower pretreatment blood folate concentrations (P < 0.001). After standardisation to pretreatment blood concentrations of homocysteine of 12 μmol/l and of folate of 12 nmol/l (approximate average concentrations for Western populations), dietary folic acid reduced blood homocysteine concentrations by 25% (95% confidence interval 23% to 28%; P < 0.001), with similar effects in the range of 0.5-5 mg folic acid daily. Vitamin B-12 (mean 0.5 mg daily) produced an additional 7% (3% to 10%) reduction in blood homocysteine. Vitamin B-6 (mean 16.5 mg daily) did not have a significant additional effect. Conclusions: Typically in Western populations, daily supplementation with both 0.5-5 mg folic acid and about 0.5 mg vitamin B-12 would be expected to reduce blood homocysteine concentrations by about a quarter to a third (for example, from about 12 μmol/l to 8-9 μmol/l). Large scale randomised trials of such regimens in high risk populations are now needed to determine whether lowering blood homocysteine concentrations reduces the risk of vascular disease.
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- Knevel, R., et al.
(author)
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A genetic variant in granzyme B is associated with progression of joint destruction in rheumatoid arthritis
- 2013
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In: Arthritis and Rheumatism. - : Wiley. - 1529-0131 .- 0004-3591. ; 65:3, s. 582-589
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Journal article (peer-reviewed)abstract
- Objective Genetic factors account for an estimated 4558% of the variance in joint destruction in rheumatoid arthritis (RA). The serine proteinase granzyme B induces target cell apoptosis, and several in vitro studies suggest that granzyme B is involved in apoptosis of chondrocytes. Serum levels of granzyme B are increased in RA and are also associated with radiographic erosions. The aim of this study was to investigate GZMB as a candidate gene accounting for the severity of joint destruction in RA. Methods A total of 1,418 patients with 4,885 radiograph sets of the hands and feet from 4 independent cohorts were studied. First, explorative analyses were performed in 600 RA patients in the Leiden Early Arthritis Clinic cohort. Fifteen single-nucleotide polymorphisms (SNPs) tagging GZMB were tested. Significantly associated SNPs were genotyped in data sets representing patients from the Groningen, Sheffield, and Lund cohorts. In each data set, the relative increase in the annual rate of progression in the presence of a genotype was assessed. Data were summarized in a meta-analysis. The association of GZMB with the RNA expression level of the GZMB genomic region was tested by mapping expression quantitative trait loci (QTLs) on 1,469 whole blood samples. Results SNP rs8192916 was significantly associated with the rate of joint destruction in the first cohort and in the meta-analysis of all data sets. Patients homozygous for the minor allele of rs8192916 had a higher rate of joint destruction per year compared with other patients (P = 7.8 x 104). Expression QTL of GZMB identified higher expression in the presence of the minor allele of rs8192916 (P = 2.27 x 105). Conclusion SNP rs8192916 located in GZMB is associated with the progression of joint destruction in RA as well as with RNA expression in whole blood.
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- Knevel, R., et al.
(author)
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Genetic variants in IL15 associate with progression of joint destruction in rheumatoid arthritis: a multicohort study
- 2012
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In: Annals of the Rheumatic Diseases. - : BMJ. - 1468-2060 .- 0003-4967. ; 71:10, s. 1651-1657
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Journal article (peer-reviewed)abstract
- Background Interleukin (IL)-15 levels are increased in serum, synovium and bone marrow of patients with rheumatoid arthritis (RA). IL-15 influences both the innate and the adaptive immune response; its major role is activation and proliferation of T cells. There are also emerging data that IL-15 affects osteoclastogenesis. The authors investigated the association of genetic variants in IL15 with the rate of joint destruction in RA. Method 1418 patients with 4885 x-ray sets of both hands and feet of four independent data sets were studied. First, explorative analyses were performed on 600 patients with early RA enrolled in the Leiden Early Arthritis Clinic. Twenty-five single-nucleotide polymorphisms (SNPs) tagging IL-15 were tested. Second, SNPs with significant associations in the explorative phase were genotyped in data sets from Groningen, Sheffield and Lund. In each data set, the relative increase of the progression rate per year in the presence of a genotype was assessed. Subsequently, data were summarised in an inverse weighting meta-analysis. Results Five SNPs were significantly associated with rate of joint destruction in phase 1 and typed in the other data sets. Patients homozygous for rs7667746, rs7665842, rs2322182, rs6821171 and rs4371699 had respectively 0.94-, 1.04-, 1.09-, 1.09- and 1.09- fold rate of joint destruction compared to other patients (p = 4.0x10(-6), p = 3.8x10(-4), p = 5.0x10(-3), p = 5.0x10(-3) and p = 9.4x10(-3)). Discussion Independent replication was not obtained, possibly due to insufficient power. Meta-analyses of all data sets combined resulted in significant results for four SNPs (rs7667746, p < 0.001; rs7665842, p < 0.001; rs4371699, p = 0.01; rs6821171, p = 0.01). These SNPs were also significant after correction for multiple testing. Conclusion Genetic variants in IL-15 are associated with progression of joint destruction in RA.
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- Visser, D., et al.
(author)
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Tau pathology as determinant of changes in atrophy and cerebral blood flow: a multi-modal longitudinal imaging study
- 2023
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In: European Journal of Nuclear Medicine and Molecular Imaging. - : Springer Science and Business Media LLC. - 1619-7070 .- 1619-7089. ; 50:8, s. 2409-19
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Journal article (peer-reviewed)abstract
- PurposeTau pathology is associated with concurrent atrophy and decreased cerebral blood flow (CBF) in Alzheimer's disease (AD), but less is known about their temporal relationships. Our aim was therefore to investigate the association of concurrent and longitudinal tau PET with longitudinal changes in atrophy and relative CBF.MethodsWe included 61 individuals from the Amsterdam Dementia Cohort (mean age 65.1 +/- 7.5 years, 44% female, 57% amyloid-beta positive [A beta +], 26 cognitively impaired [CI]) who underwent dynamic [F-18]flortaucipir PET and structural MRI at baseline and 25 +/- 5 months follow-up. In addition, we included 86 individuals (68 CI) who only underwent baseline dynamic [F-18]flortaucipir PET and MRI scans to increase power in our statistical models. We obtained [F-18]flortaucipir PET binding potential (BPND) and R-1 values reflecting tau load and relative CBF, respectively, and computed cortical thickness from the structural MRI scans using FreeSurfer. We assessed the regional associations between i) baseline and ii) annual change in tau PET BPND in Braak I, III/IV, and V/VI regions and cortical thickness or R-1 in cortical gray matter regions (spanning the whole brain) over time using linear mixed models with random intercepts adjusted for age, sex, time between baseline and follow-up assessments, and baseline BPND in case of analyses with annual change as determinant. All analyses were performed in A beta- cognitively normal (CN) individuals and A beta+ (CN and CI) individuals separately.ResultsIn A beta+ individuals, greater baseline Braak III/IV and V/VI tau PET binding was associated with faster cortical thinning in primarily frontotemporal regions. Annual changes in tau PET were not associated with cortical thinning over time in either A beta+ or A beta- individuals. Baseline tau PET was not associated with longitudinal changes in relative CBF, but increases in Braak III/IV tau PET over time were associated with increases in parietal relative CBF over time in A beta + individuals.ConclusionWe showed that higher tau load was related to accelerated cortical thinning, but not to decreases in relative CBF. Moreover, tau PET load at baseline was a stronger predictor of cortical thinning than change of tau PET signal.
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- Krabben, A., et al.
(author)
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Association of Genetic Variants in the IL4 and IL4R Genes With the Severity of Joint Damage in Rheumatoid Arthritis: A Study in Seven Cohorts
- 2013
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In: Arthritis and Rheumatism. - : Wiley. - 1529-0131 .- 0004-3591. ; 65:12, s. 3051-3057
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Journal article (peer-reviewed)abstract
- ObjectiveThe progression of joint destruction in rheumatoid arthritis (RA) is determined by genetic factors. Changes in IL4 and IL4R genes have been associated with RA severity, but this finding has not been replicated. This study was undertaken to investigate the association between IL4- and IL4R-tagging single-nucleotide polymorphisms (SNPs) and the progression rate of joint damage in RA in a multicohort candidate gene study. MethodsIL4- and IL4R-tagging SNPs (n = 8 and 39, respectively) were genotyped in 600 RA patients for whom 2,846 sets of radiographs of the hands and feet were obtained during 7 years of followup. Subsequently, SNPs significantly associated with the progression of joint damage were genotyped and studied in relation to 3,415 radiographs of 1,953 RA patients; these included data sets from Groningen (The Netherlands), Lund (Sweden), Sheffield (UK), the North American Rheumatoid Arthritis Consortium (US), Wichita (US), and the National Data Bank (US). The relative increase in progression rate per year in the presence of a genotype was determined in each cohort. An inverse variance weighting meta-analysis was performed on the 6 data sets that together formed the replication phase. ResultsIn the discovery phase, none of the IL4 SNPs and 7 of the IL4R SNPs were significantly associated with the joint damage progression rate. In the replication phase, 2 SNPs in the IL4R gene were significantly associated with the joint damage progression rate (rs1805011 [P = 0.02] and rs1119132 [P = 0.001]). ConclusionGenetic variants in IL4R were identified, and their association with the progression rate of joint damage in RA was independently replicated.
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