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Search Results: 1 - 10 of 1642 matches for " Petra Verhoef "
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Effect of Homocysteine-Lowering Nutrients on Blood Lipids: Results from Four Randomised, Placebo-Controlled Studies in Healthy Humans
Margreet R Olthof ,Trinette van Vliet,Petra Verhoef,Peter L Zock,Martijn B Katan
PLOS Medicine , 2005, DOI: 10.1371/journal.pmed.0020135
Abstract: Background Betaine (trimethylglycine) lowers plasma homocysteine, a possible risk factor for cardiovascular disease. However, studies in renal patients and in obese individuals who are on a weight-loss diet suggest that betaine supplementation raises blood cholesterol; data in healthy individuals are lacking. Such an effect on cholesterol would counteract any favourable effect on homocysteine. We therefore investigated the effect of betaine, of its precursor choline in the form of phosphatidylcholine, and of the classical homocysteine-lowering vitamin folic acid on blood lipid concentrations in healthy humans. Methods and Findings We measured blood lipids in four placebo-controlled, randomised intervention studies that examined the effect of betaine (three studies, n = 151), folic acid (two studies, n = 75), and phosphatidylcholine (one study, n = 26) on plasma homocysteine concentrations. We combined blood lipid data from the individual studies and calculated a weighted mean change in blood lipid concentrations relative to placebo. Betaine supplementation (6 g/d) for 6 wk increased blood LDL cholesterol concentrations by 0.36 mmol/l (95% confidence interval: 0.25–0.46), and triacylglycerol concentrations by 0.14 mmol/l (0.04–0.23) relative to placebo. The ratio of total to HDL cholesterol increased by 0.23 (0.14–0.32). Concentrations of HDL cholesterol were not affected. Doses of betaine lower than 6 g/d also raised LDL cholesterol, but these changes were not statistically significant. Further, the effect of betaine on LDL cholesterol was already evident after 2 wk of intervention. Phosphatidylcholine supplementation (providing approximately 2.6 g/d of choline) for 2 wk increased triacylglycerol concentrations by 0.14 mmol/l (0.06–0.21), but did not affect cholesterol concentrations. Folic acid supplementation (0.8 mg/d) had no effect on lipid concentrations. Conclusions Betaine supplementation increased blood LDL cholesterol and triacylglycerol concentrations in healthy humans, which agrees with the limited previous data. The adverse effects on blood lipids may undo the potential benefits for cardiovascular health of betaine supplementation through homocysteine lowering. In our study phosphatidylcholine supplementation slightly increased triacylglycerol concentrations in healthy humans. Previous studies of phosphatidylcholine and blood lipids showed no clear effect. Thus the effect of phosphatidylcholine supplementation on blood lipids remains inconclusive, but is probably not large. Folic acid supplementation does not seem to affect blood lipids and
Effect of Folic Acid and Betaine Supplementation on Flow-Mediated Dilation: A Randomized, Controlled Study in Healthy Volunteers
Margreet R Olthof, Michiel L Bots, Martijn B Katan, Petra Verhoef
PLOS ONE , 2006, DOI: 10.1371/journal.pctr.0010010
Abstract: Objectives We investigated whether lowering of fasting homocysteine concentrations, either with folic acid or with betaine supplementation, differentially affects vascular function, a surrogate marker for risk of cardiovascular disease, in healthy volunteers. As yet, it remains uncertain whether a high concentration of homocysteine itself or whether a low folate status—its main determinant—is involved in the pathogenesis of cardiovascular disease. To shed light on this issue, we performed this study. Design This was a randomized, placebo-controlled, double-blind, crossover study. Setting The study was performed at Wageningen University in Wageningen, the Netherlands. Participants Participants were 39 apparently healthy men and women, aged 50–70 y. Interventions Participants ingested 0.8 mg/d of folic acid, 6 g/d of betaine, and placebo for 6 wk each, with 6-wk washout in between. Outcome Measures At the end of each supplementation period, plasma homocysteine concentrations and flow-mediated dilation (FMD) of the brachial artery were measured in duplicate. Results Folic acid supplementation lowered fasting homocysteine by 20% (?2.0 μmol/l, 95% confidence interval [CI]: ?2.3; ?1.6), and betaine supplementation lowered fasting plasma homocysteine by 12% (?1.2 μmol/l; ?1.6; ?0.8) relative to placebo. Mean (± SD) FMD after placebo supplementation was 2.8 (± 1.8) FMD%. Supplementation with betaine or folic acid did not affect FMD relative to placebo; differences relative to placebo were ?0.4 FMD% (95%CI, ?1.2; 0.4) and ?0.1 FMD% (?0.9; 0.7), respectively. Conclusions Folic acid and betaine supplementation both did not improve vascular function in healthy volunteers, despite evident homocysteine lowering. This is in agreement with other studies in healthy participants, the majority of which also fail to find improved vascular function upon folic acid treatment. However, homocysteine or folate might of course affect cardiovascular disease risk through other mechanisms. Trial Registration ClinicalTrials.gov NCT00102843
Acute Effect of Folic Acid, Betaine, and Serine Supplements on Flow-Mediated Dilation after Methionine Loading: A Randomized Trial
Margreet R Olthof, Michiel L Bots, Martijn B Katan, Petra Verhoef
PLOS ONE , 2006, DOI: 10.1371/journal.pctr.0010004
Abstract: Objectives We investigated whether reducing post-methionine homocysteine concentrations via various treatments other than folic acid affects vascular function, as measured through flow-mediated dilation (FMD) of the brachial artery. High fasting and post-methionine homocysteine concentrations are associated with cardiovascular disease risk, but homocysteine might be a surrogate marker for low folate status. Design This was a randomized, placebo-controlled, double-blind, crossover study. Setting The study took place at Wageningen University in Wageningen in the Netherlands. Participants Participants were 39 apparently healthy men and women, aged 50–70 y. Interventions Participants ingested 10 mg of folic acid, 3 g of betaine, 5 g of serine, and placebo together with an oral methionine load. Each supplement was tested on two different days. Outcome Measures On each of the eight treatment days, plasma homocysteine concentrations and FMD were measured before (t = 0 h, fasting) and 6 h (t = 6 h) after methionine loading. Results The mean (± SD) fasting homocysteine concentrations averaged over the eight test days were 9.6 ± 2.1 μmol/l. Mean fasting FMD was 3.1 ± 2.4 FMD%. A methionine load with placebo increased homocysteine concentrations by 17.2 ± 9.3 μmol/l at 6 h after loading, similar to the increase following methionine loading with folic acid. A methionine load together with betaine and with serine increased homocysteine by 10.4 ± 2.8 μmol/l (p < 0.001 relative to placebo) and by 12.1 ± 8.2 μmol/l (p < 0.001 relative to placebo), respectively. Methionine loading with placebo did not affect FMD, and neither did methionine loading with folic acid, betaine, or serine; differences relative to placebo were +0.7 FMD% (95%CI, ?0.6; 1.9), +0.2 FMD% (?1.0; 1.3), and +0.3 FMD% (?0.8; 1.4), respectively. Conclusions Experimentally induced acute changes in homocysteine concentrations did not affect FMD in healthy volunteers. This implies that potential adverse effects of high homocysteine concentrations on the cardiovascular system are not mediated through vascular function. However, homocysteine or folate may affect cardiovascular disease risk through other mechanisms. Trial Registration ClinicalTrials.gov NCT00126347
No Effect of Folic Acid Supplementation on Global DNA Methylation in Men and Women with Moderately Elevated Homocysteine
Audrey Y. Jung, Yvo Smulders, Petra Verhoef, Frans J. Kok, Henk Blom, Robert M. Kok, Ellen Kampman, Jane Durga
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0024976
Abstract: A global loss of cytosine methylation in DNA has been implicated in a wide range of diseases. There is growing evidence that modifications in DNA methylation can be brought about by altering the intake of methyl donors such as folate. We examined whether long-term daily supplementation with 0.8 mg of folic acid would increase global DNA methylation compared with placebo in individuals with elevated plasma homocysteine. We also investigated if these effects were modified by MTHFR C677T genotype. Two hundred sixteen participants out of 818 subjects who had participated in a randomized double-blind placebo-controlled trial were selected, pre-stratified on MTHFR C677T genotype and matched on age and smoking status. They were allocated to receive either folic acid (0.8 mg/d; n = 105) or placebo treatment (n = 111) for three years. Peripheral blood leukocyte DNA methylation and serum and erythrocyte folate were assessed. Global DNA methylation was measured using liquid chromatography-tandem mass spectrometry and expressed as a percentage of 5-methylcytosines versus the total number of cytosine. There was no difference in global DNA methylation between those randomized to folic acid and those in the placebo group (difference = 0.008, 95%CI = ?0.05,0.07, P = 0.79). There was also no difference between treatment groups when we stratified for MTHFR C677T genotype (CC, n = 76; CT, n = 70; TT, n = 70), baseline erythrocyte folate status or baseline DNA methylation levels. In moderately hyperhomocysteinemic men and women, long-term folic acid supplementation does not increase global DNA methylation in peripheral blood leukocytes. ClinicalTrials.gov NCT00110604
Postmodernism and the need for story and promise: How Robert Jenson's theology addresses some postmodern challenges to faith
AH Verhoef
Acta Theologica , 2012,
Abstract: Modernity’s belief that we live in a narratable world (a world with a story) and its confidence in progress (a world with a promise), are terminated by postmodernism’s insights. This is how the American Lutheran theologian Robert Jenson understands the impact of postmodernism. If this is true, it poses great challenges for the Christian faith to be communicated and accepted within this context. This article assesses how Jenson’s theology attempts to address postmodernism’s need for a new story and promise. It concludes that Jenson’s theology, as a Trinitarian theology, forms a coherent answer to these challenges because it is a narrative and eschatological theology. This article indicates, amongst other things the importance of Jenson’s understanding in his theology of the relation between God and time. The significance of Jenson’s approach is that it, firstly, understands the church as a narratable world, with a visible promise, and that it, secondly, follows a characteristically postmodern methodology in addressing these challenges.
Thessalonians 4:1-8: The Thessalonians should live a holy life
E Verhoef
HTS Theological Studies/Teologiese Studies , 2007,
Abstract: The author argues that 1 Thessalonians 4:1-8 should be considered as one coherent pericope. It shows that the term “holiest” does not refer to the god “Kabeiros”, neither that the Greek word “skeuos” means either “spouse” or referring to the male sexual organ. It rather means “body”. The article aims to argue that 1 Thessalonians 4:1-8 is a passage in which Paul urges the Thessalonians to be always pure in body and mind. Thus explained, the pericope fits in with the preceding text about the Thessalonians' holiness at the parousia (3:13) and it prepares for the next paragraph in which the parousia of the Lord with the holy people (3:13) is discussed more thoroughly (1 Th 4:13-5:11). HTS Theological Studies Vol. 63 (1) 2007: pp. 347-363
Christians reacted differently to non-Christian cults
E Verhoef
HTS Theological Studies/Teologiese Studies , 2011,
Abstract: Christians were confronted with many other religions during the expansion of Christianity. What was their attitude towards these other religions? Apparently Christians reacted very differently. Earlier I argued that the Christians in Philippi adopted some elements of the cult of Euephenes, an initiate in the Kabeiric cult of Samothrace. The Kabeiric cult was very much present in Thessalonica as well. In this article I argued that, here too, Christians took over some elements of the Kabeiric cult. In some other cities non-Christian cults were eliminated. These different reactions towards other religions and cults seemed to stem from the local situation. In particular, local religious customs seem to have been adopted and to have taken precedence over well-known national or even international religions. Apparently, it was very difficult for people to abandon strong local rituals. In 1997, Andries van Aarde and Sanrie van Zijl published a very interesting article in which they drew attention to the pagan Hellenistic background that may have played a role in the development of Christology. Though more aspects should be taken into consideration it is self-evident to me that the entire history of the Christian church can be understood only against the background of the whole contemporary world. For example, Christians reacted very differently to non-Christian cults after they had assumed power in the Roman Empire. Sometimes temples and shrines were devastated, sometimes they were reused as churches. And sometimes elements of other cults were adopted in a more or less Christianised form. Recently I argued that in Philippi the cult of Euephenes, an initiate in the cult of the Kabeiroi on Samothrace, was succeeded by the veneration of Paul. In the present article, however, I focused on the cult of Kabeiros in Thessalonica and its impact on the cult of Demetrios that was already thriving there, whereby the latter cult began to incorporate elements of the former. I concluded the article with short remark about the way Christians elsewhere adopted or rejected other cults, touching on the question why, in some cases, an older cult was integrated into the Christian cult and why it was terminated in other cases.
Syncretism in the church of Philippi
E Verhoef
HTS Theological Studies/Teologiese Studies , 2008,
Abstract: It has been known for a long time that the history of Christianity has seen the incorporation of syncretistic elements. This is not at all exceptional. On the contrary, in order to grow, any religion necessarily fits in with the existing frame of reference. It is hardly surprising then, that elements of Hellenistic hero worship were adopted in the veneration of the Christian martyrs. Over a century ago, E Lucius presented several examples of such phenomena in his book, Die Anf nge des Heiligenkults in der christlichen Kirche (1904), arguing that Christian churches adopted several rituals and ideas from older pagan cults. Indeed, excavations in Philippi have revealed a connection in the first decades of the fourth century between the Christian cult and the cult of a certain Euephenes, son of Exekestos. He was probably an initiate into the mystery cult of the Kabeiroi. This can only mean that in Philippi as elsewhere syncretistic elements must have crept in. In the beginning of the fourth century the Basilica of Paul was added onto the Hellenistic shrine, so that the buildings shared one wall. In the first half of the fifth century this Basilica was replaced by the bigger Octagon. A baptistery was constructed, and the Hellenistic heroon was incorporated into these buildings. Around this time the cult of the Hellenistic hero Euephenes was supplanted by the veneration of the Christian hero par excellence, the apostle Paul. HTS Theological Studies Vol. 64 (2) 2008: pp. 697-714
Notes on Archaeology and Prehistoric Mining in the Kruger National Park
J. Verhoef
Koedoe : African Protected Area Conservation and Science , 1986, DOI: 10.4102/koedoe.v29i1.527
Abstract: Archaeological research in the Kruger National Park (KNP) was formally instituted in 1963. During 1973 the National Parks Board of Trustees allocated an archaeo-ethnological research project to the Department of Archaeology, University of Pretoria and this step revealed that the KNP has an important archaelogical research potential. A review of these reconnaissance activities (between 1973-1983) is given and the chronology of archaeological sites and finds (Early, Middle and Late Stone Ages) in the KNP are briefly discussed. Data are also presented on the Iron Age and localities of prehistoric mining activities are identified.
Syncretism in the church of Philippi
Eduard Verhoef
HTS Theological Studies/Teologiese Studies , 2009, DOI: 10.4102/hts.v64i2.54
Abstract: It has been known for a long time that the history of Christianity has seen the incorporation of syncretistic elements. This is not at all exceptional. On the contrary, in order to grow, any religion necessarily fits in with the existing frame of reference. It is hardly surprising then, that elements of Hellenistic hero worship were adopted in the veneration of the Christian martyrs. Over a century ago, E Lucius presented several examples of such phenomena in his book, Die Anf nge des Heiligenkults in der christlichen Kirche (1904), arguing that Christian churches adopted several rituals and ideas from older pagan cults. Indeed, excavations in Philippi have revealed a connection in the first decades of the fourth century between the Christian cult and the cult of a certain Euephenes, son of Exekestos. He was probably an initiate into the mystery cult of the Kabeiroi. This can only mean that in Philippi as elsewhere syncretistic elements must have crept in. In the beginning of the fourth century the Basilica of Paul was added onto the Hellenistic shrine, so that the buildings shared one wall. In the first half of the fifth century this Basilica was replaced by the bigger Octagon. A baptistery was constructed, and the Hellenistic heroon was incorporated into these buildings. Around this time the cult of the Hellenistic hero Euephenes was supplanted by the veneration of the Christian hero par excellence, the apostle Paul.
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