Staff Publications

Staff Publications

  • external user (warningwarning)
  • Log in as
  • language uk
  • About

    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

    We have a manual that explains all the features 

Current refinement(s):

Records 1 - 9 / 9

  • help
  • print

    Print search results

  • export

    Export search results

  • alert
    We will mail you new results for this query: keywords==vitamin-b-12
Check title to add to marked list
The association between plasma homocysteine levels and bone quality and bone mineral density parameters in older persons
Enneman, A.W. ; Swart, K.M.A. ; Zillikens, M.C. ; Dijk, S.C. van; Wijngaarden, J.P. van; Brouwer-Brolsma, E.M. ; Dhonukshe-Rutten, R.A.M. ; Hofman, A. ; Rivadeneira, F. ; Cammen, T.J.M. van der; Lips, P. ; Groot, C.P.G.M. de; Uitterlinden, A.G. ; Meurs, J.B.J. van; Schoor, N.M. van; Velde, N. van der - \ 2014
Bone 63 (2014). - ISSN 8756-3282 - p. 141 - 146.
band ultrasound attenuation - quantitative ultrasound - postmenopausal women - fracture risk - osteoporotic fracture - elderly-people - vitamin-b-12 - homocystinuria - mortality - turnover
Introduction High plasma homocysteine levels have been associated with incident osteoporotic fractures, but the mechanisms underlying this association are still unknown. It has been hypothesized that homocysteine might interfere with collagen cross-linking in bone, thereby weakening bone structure. Therefore, we wanted to investigate whether plasma homocysteine levels are associated with bone quality parameters, rather than with bone mineral density. Methods Cross-sectional data of the B-PROOF study (n = 1227) and of two cohorts of the Rotterdam Study (RS-I (n = 2850) and RS-II (n = 2023)) were used. Data on bone mineral density of the femoral neck and lumbar spine were obtained in these participants using dual-energy X-ray assessment (DXA). In addition, participants of B-PROOF and RS-I underwent quantitative ultrasound measurement of the calcaneus, as a marker for bone quality. Multiple linear regression analysis was used to investigate the associations between natural-log transformed plasma levels of homocysteine and bone mineral density or ultrasound parameters. Results Natural-log transformed homocysteine levels were inversely associated with femoral neck bone mineral density in the two cohorts of the Rotterdam Study (B = - 0.025, p = 0.004 and B = - 0.024, p = 0.024). In B-PROOF, no association was found. Pooled data analysis showed significant associations between homocysteine and bone mineral density at both femoral neck (B = - 0.032, p = 0.010) and lumbar spine (B = - 0.098, p = 0.021). Higher natural-log transformed homocysteine levels associated significantly with lower bone ultrasound attenuation in B-PROOF (B = - 3.7, p = 0.009) and speed of sound in both B-PROOF (B = - 8.9, p = 0.001) and RS-I (B = - 14.5, p = 0.003), indicating lower bone quality. Pooled analysis confirmed the association between homocysteine and SOS (B = - 13.1, p = 0.016). Results from ANCOVA-analysis indicate that differences in SOS and BUA between participants having a plasma homocysteine level above or below median correspond to 0.14 and 0.09 SD, respectively. Discussion In this study, plasma levels of homocysteine were significantly inversely associated with both bone ultrasound parameters and with bone mineral density. However, the size of the associations seems to be of limited clinical relevance and may therefore not explain the previously observed association between plasma homocysteine and osteoporotic fracture incidence.
A statistical method to base nutrient recommendations on meta-analysis of intake and health-related status biomarkers.
Voet, H. van der; Boer, W.J. de; Souverein, O.W. ; Doets, E.L. ; Veer, P. van 't - \ 2014
PLoS ONE 9 (2014)3. - ISSN 1932-6203
intake values - vitamin-b-12 - population - bioavailability - homocysteine - trials - models - adults - level - nivs
Nutrient recommendations in use today are often derived from relatively old data of few studies with few individuals. However, for many nutrients, including vitamin B-12, extensive data have now become available from both observational studies and randomized controlled trials, addressing the relation between intake and health-related status biomarkers. The purpose of this article is to provide new methodology for dietary planning based on dose-response data and meta-analysis. The methodology builds on existing work, and is consistent with current methodology and measurement error models for dietary assessment. The detailed purposes of this paper are twofold. Firstly, to define a Population Nutrient Level (PNL) for dietary planning in groups. Secondly, to show how data from different sources can be combined in an extended meta-analysis of intake-status datasets for estimating PNL as well as other nutrient intake values, such as the Average Nutrient Requirement (ANR) and the Individual Nutrient Level (INL). For this, a computational method is presented for comparing a bivariate lognormal distribution to a health criterion value. Procedures to meta-analyse available data in different ways are described. Example calculations on vitamin B-12 requirements were made for four models, assuming different ways of estimating the dose-response relation, and different values of the health criterion. Resulting estimates of ANRs and less so for INLs were found to be sensitive to model assumptions, whereas estimates of PNLs were much less sensitive to these assumptions as they were closer to the average nutrient intake in the available data.
Metagenome analysis reveals yet unexplored reductive dechlorinating potential of Dehalobacter sp. E1 growing in coculture with Sedimentibacter sp.
Maphosa, F. ; Passel, M.W.J. van; Vos, W.M. de; Smidt, H. - \ 2012
Environmental Microbiology Reports 4 (2012)6. - ISSN 1758-2229 - p. 604 - 616.
desulfitobacterium-frappieri pcp-1 - complete genome sequence - dehalococcoides spp. - online tool - hafniense - tetrachloroethene - dehalogenation - vitamin-b-12 - restrictus - bacterium
The importance of Dehalobacter species in bioremediation as dedicated degraders of chlorinated organics has been well recognized. However, still little is known about Dehalobacter's full genomic repertoires, including the genes involved in dehalogenation. Here we report the first insights into the genome sequence of Dehalobacter sp. E1 that grows in strict co-culture with Sedimentibacter sp. B4. Based on the co-culture metagenome and the genome of strain B4 (4.2¿Mbp) we estimate the genome sequence of strain E1 to be 2.6¿Mbp. Ten putative reductive dehalogenase homologue (Rdh)-encoding gene clusters were identified. One cluster has a putative tetrachloroethene Rdh-encoding gene cluster, similar to the pceABCT operon previously identified in Dehalobacter restrictus. Metagenome analysis indicated that the inability of strain E1 to synthesize cobalamin, an essential cofactor of reductive dehalogenases, is complemented by Sedimentibacter. The metagenomic exploration described here maps the extensive dechlorinating potential of Dehalobacter, and paves way for elucidation of the interactions with its co-cultured Sedimentibacter
Structural, functional and molecular analysis of the effects of aging in the small intestine and colon of C57BL/6 J mice.
Steegenga, W.T. ; Wit, N.J.W. de; Boekschoten, M.V. ; IJssenagger, N. ; Lute, C. ; Keshtkar, S. ; Grootte Bromhaar, M.M. ; Kampman, E. ; Groot, C.P.G.M. de; Muller, M.R. - \ 2012
BMC Medical Genomics 5 (2012). - ISSN 1755-8794 - 27 p.
bacterial overgrowth - age-changes - stem-cells - inflammation - mucosa - cancer - vitamin-b-12 - homeostasis - microbiota - patterns
Background By regulating digestion and absorption of nutrients and providing a barrier against the external environment the intestine provides a crucial contribution to the maintenance of health. To what extent aging-related changes in the intestinal system contribute to the functional decline associated with aging is still under debate. Methods Young (4 M) and old (21 M) male C57BL/6 J mice were fed a control low-fat (10E%) or a high-fat diet (45E%) for 2 weeks. During the intervention gross energy intake and energy excretion in the feces were measured. After sacrifice the small and large intestine were isolated and the small intestine was divided in three equal parts. Swiss rolls were prepared of each of the isolated segments for histological analysis and the luminal content was isolated to examine alterations in the microflora with 16S rRNA Q-PCR. Furthermore, mucosal scrapings were isolated from each segment to determine differential gene expression by microarray analysis and global DNA methylation by pyrosequencing. Results Digestible energy intake was similar between the two age groups on both the control and the high-fat diet. Microarray analysis on RNA from intestinal scrapings showed no marked changes in expression of genes involved in metabolic processes. Decreased expression of Cubilin was observed in the intestine of 21-month-old mice, which might contribute to aging-induced vitamin B12 deficiency. Furthermore, microarray data analysis revealed enhanced expression of a large number of genes involved in immune response and inflammation in the colon, but not in the small intestine of the 21-month-old mice. Aging-induced global hypomethylation was observed in the colon and the distal part of the small intestine, but not in the first two sections of the small intestine. Conclusion In 21-month old mice the most pronounced effects of aging were observed in the colon, whereas very few changes were observed in the small intestine.
Dosing of anaerobic granular sludge bioreactors with cobalt: Impact of cobalt retention on methanogenic activity
Fermoso, F.G. ; Bartacek, J. ; Manzano, R. ; Leeuwen, H.P. van; Lens, P.N.L. - \ 2010
Bioresource Technology 101 (2010)24. - ISSN 0960-8524 - p. 9429 - 9437.
degradation - vitamin-b-12 - reactor - nickel - iron - deprivation - cadmium - ions
The effect of dosing a metal limited anaerobic sludge blanket (UASB) reactor with a metal pulse on the methanogenic activity of granular sludge has thus far not been successfully modeled. The prediction of this effect is crucial in order to optimize the strategy for metal dosage and to prevent unnecessary losses of resources. This paper describes the relation between the initial immobilization of cobalt in anaerobic granular sludge cobalt dosage into the reactor and the evolution of methanogenic activity during the subsequent weeks. An operationally defined parameter (A0·B0) was found to combine the amount of cobalt immobilized instantaneously upon the pulse (B0) and the amount of cobalt immobilized within the subsequent 24 h (A0). In contrast with the individual parameters A0 and B0, the parameter A0·B0 correlated significantly with the methanogenic activity of the sludge during the subsequent 16 or 35 days. This correlation between metal retention and activity evolution is a useful tool to implement trace metal dosing strategies for biofilm-based biotechnological processes.
What can we learn from the FACIT trial: A randomized, double blind, controlled trial
Durga, J. ; Boxtel, M.P.J. van; Schouten, E.G. ; Kok, F.J. ; Jolles, J. ; Katan, M.B. ; Verhoef, P. - \ 2007
Journal of Nutrition, Health and Aging 11 (2007)4. - ISSN 1279-7707 - p. 320 - 324.
folic-acid supplementation - cognitive function - memory performance - elderly-patients - homocysteine - dementia - vitamin-b-12 - disease - people - folate
Validation of a food frequency questionnaire to assess folate intake of Dutch elderly people
Rest, O. van de; Durga, J. ; Verhoef, P. ; Boonstra, A. ; Brants, H.A.M. - \ 2007
The British journal of nutrition 98 (2007)5. - ISSN 0007-1145 - p. 1014 - 1020.
folic-acid - homocysteine concentrations - dietary assessment - heart-disease - plasma folate - biomarker - fruit - risk - vitamin-b-12 - population
Folate is required for 1-carbon metabolism and deficiency in folate leads to megaloblastic anemia. Low levels of folate have been associated with increased risk of vascular disease. To investigate whether RDA of folate are met, habitual folate intake needs to be assessed reliably. We developed a FFQ to specifically measure folate intake over the previous 3 months in elderly people in the Netherlands. Major sources of folate intake, i.e. foods contributing to at least 80 % of the average folate intake, were identified through an analysis of the second Dutch Food Consumption Survey for the sub-population of men and women aged 50¿70. In 2000 and 2001, folate intake was estimated with this questionnaire in 1286 individuals aged 50-75 years. Concentrations of serum and erythrocyte folate served as biomarkers with which relative validity of the questionnaire was assessed. The same FFQ was repeated after 3 years in 803 subjects in order to assess long-term reproducibility. Mean folate intake was estimated to be 196 (sd 69) ¿g/d. Spearman correlation coefficients between folate intake and serum and erythrocyte concentrations were 0·14 (P <0·01) and 0·05 (P = 0·06) respectively. Spearman correlations between folate intakes measured at baseline and after 3 years were 0·58 (P <0·01). 47 % of the participants were classified in the same quartiles on the two occasions. Our FFQ showed a weak correlation between folate intake and blood folate concentrations and reproducibility was acceptable. This FFQ is able to rank subjects according to their folate intake.
Association of folate with hearing is dependent on the 5, 10-methylenetetrahydrofolate reductase 677C-->T mutation
Durga, J. ; Anteunis, L.J.C. ; Schouten, E.G. ; Bots, M.L. ; Kok, F.J. ; Verhoef, P. - \ 2006
Neurobiology of aging 27 (2006)3. - ISSN 0197-4580 - p. 482 - 489.
cardiovascular risk-factors - methylenetetrahydrofolate reductase - homocysteine concentrations - common mutation - disease - plasma - epidemiology - atherosclerosis - vitamin-b-12 - impairment
Vascular disease and its risk factors have been associated with the age-related hearing loss. We examined the association of elevated plasma homocysteine and its determinants with hearing levels. Pure-tone air conduction thresholds in 728 individuals with sensorineural hearing loss were not associated with homocysteine, erythrocyte folate and Vitamin B6. Low concentrations of serum folate and Vitamin B12 were associated with better hearing. When folate status was below the median, 5,10-methylenetetrahydrofolate reductase (MTHFR) 677TT homozygotes had similar hearing levels to subjects with a C allele. However, when folate status was above the median, MTHFR 677TT homozygotes had on an average 5 dB (p = 0.037) and 2.6 dB (p = 0.021) lower PTA-high and PTA-low hearing thresholds, respectively, than the subjects with a 677C allele. The relationship between serum folate and hearing thresholds appeared to be dependent on MTHFR 677 genotype (CC, r = 0.13, p = 0.034; TT, r = -0.10, p = 0.291). This supports the hypothesis that a greater one-carbon moiety commitment to de novo synthesis of nucleotides and an increase in formyl-folate derivatives relative to methyl-folate derivatives is protective for hearing.
Homocysteine and cognitive function in institutionalised elderly : a cross-sectional analysis
Manders, M. ; Vasse, E. ; Groot, C.P.G.M. de; Staveren, W.A. van; Bindels, J.G. ; Blom, H.J. ; Hoefnagels, W.H.L. - \ 2006
European Journal of Nutrition 45 (2006)2. - ISSN 1436-6207 - p. 70 - 78.
alzheimers-disease - plasma homocysteine - cardiovascular-disease - impairment - scale - vitamin-b-12 - performance - deficiency - people - folate
Several cross¿sectional, case¿control and prospective studies revealed a relation between homocysteine and cognitive function or dementia. These studies included either patient populations or healthy, community¿ dwelling elderly people. Aim of the study In this study we tested the hypothesis that homocysteine was inversely associated with cognitive function in a population of institutionalised elderly (aged ¿ 60 y; n = 157). For testing this hypothesis baseline data of a recently conducted intervention study in institutionalised elderly (median age 83 years) were used. Cognitive function was evaluated by the cognitive subscale of the Alzheimer's disease Assessment Scale (ADAS¿cog). The association between fasting plasma homocysteine level and cognitive function was investigated by multiple linear regression analysis. In the crude model homocysteine concentration was not significantly related to ADAS¿cog score (ß = 0.061; p = 0.45).Age was found to be related to ADAS¿cog score (ß = 0.161; p <0.05). Adjusting for age did however not result in a relation between homocysteine and cognitive function. In our study no association was found between homocysteine and cognitive function in a population of very old institutionalised subjects
Check title to add to marked list

Show 20 50 100 records per page

 
Please log in to use this service. Login as Wageningen University & Research user or guest user in upper right hand corner of this page.