681 results on '"Obeid, Rima"'
Search Results
202. Folate and Methylation Status in Relation to Phosphorylated Tau Protein(181P) and β-Amyloid(1–42) in Cerebrospinal Fluid
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Obeid, Rima, primary, Kasoha, Mariz, primary, Knapp, Jean-Pierre, primary, Kostopoulos, Panagiotis, primary, Becker, George, primary, Fassbender, Klaus, primary, and Herrmann, Wolfgang, primary
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- 2007
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203. Biomarkers of Folate and Vitamin B12 Are Related in Blood and Cerebrospinal Fluid
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Obeid, Rima, primary, Kostopoulos, Panagiotis, primary, Knapp, Jean-Pierre, primary, Kasoha, Mariz, primary, Becker, George, primary, Fassbender, Klaus, primary, and Herrmann, Wolfgang, primary
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- 2007
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204. Holotranscobalamin in laboratory diagnosis of cobalamin deficiency compared to total cobalamin and methylmalonic acid
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Obeid, Rima, primary and Herrmann, Wolfgang, additional
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- 2007
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205. Hyperhomocysteinaemia: A Critical Review of Old and New Aspects
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Herrmann, Wolfgang, primary, Herrmann, Markus, additional, and Obeid, Rima, additional
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- 2007
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206. Cobalamin coenzyme forms are not likely to be superior to cyano- and hydroxyl-cobalamin in prevention or treatment of cobalamin deficiency.
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Obeid, Rima, Fedosov, Sergey N., and Nexo, Ebba
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- 2015
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207. Serum Unmetabolized Folic Acid: The Straw That Broke Dihydrofolate Reductase's Back?
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Obeid, Rima
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FOLIC acid , *CHILD nutrition , *ADOLESCENT nutrition , *VITAMINS in human nutrition , *FASTING , *SERUM , *PHYSIOLOGY - Abstract
The article discusses research done on serum unmetabolized folic acid (UMFA). It references the study "Unmetabolized Folic Acid Is Detected in Nearly All Serum Samples From US Children, Adolescents, and Adults" by C. M. Pfeiffer and colleagues published within the issue. Topics discussed include the effects of vitamin use and fasting conditions on folate forms, the effect of vitamin usage on UMFA, and predictors of the presence of UMFA in serum.
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- 2015
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208. One year B-vitamins increases serum and whole blood folate forms and lowers plasma homocysteine in older German.
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Kirsch, Susanne H., Herrmann, Wolfgang, Kruse, Vera, Eckert, Rudolf, Gräber, Stefan, Geisel, Jürgen, and Obeid, Rima
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VITAMIN B in human nutrition ,FOLIC acid in human nutrition ,SERUM ,BLOOD plasma ,HOMOCYSTEINE in the body - Abstract
Background: We aimed to study the effect of long-term supplementation of B-vitamins on folate forms in serum and whole blood (WB) in elderly German subjects. Methods: 59 participants (mean age 67 years) were randomized to daily receive either vitamin D3 (1200 IU), folic acid (500 μg), vitamin B12 (500 μg), vitamin B6 (50 mg), and calcium carbonate (456 mg) or vitamin D3 plus calcium carbonate. Serum and WB folate forms were measured before and after 6 and 12 months. Results: B-vitamins supplementation for 6 months led to higher concentrations of 5-methyltetrahydrofolate (5-methylTHF) in serum (mean 49.1 vs. 19.6 nmol/L) and WB (1332 vs. 616 nmol/L). Also non-methyl-folate concentrations in serum and WB were higher after 6 months with B-vitamins supplementation. Unmetabolized folic acid (UFA) increased after supplementation. tHcy concentration was lowered after 1 year of B-vitamin supplementation (mean 13.1 vs. 9.6 μmol/L). A stronger reduction of tHcy after 1 year was found in participants who had baseline level > 12.5 μmol/L (mean 17.0 vs. 11.9 μmol/L) compared to those with baseline tHcy lower than this limit (mean 9.1 vs. 7.4 μmol/L). In contrast, the increases in serum and WB 5-methylTHF were comparable between the two group Conclusions: One year B-vitamins supplementation increased the levels of 5-methylTHF and non-methylfolate in serum and WB, normalized tHcy, but caused an increase in the number of cases with detectable UFA in serum. Lowering of tHcy was predicted by baseline tHcy, but not by baseline serum or WB 5-methylTHF. [ABSTRACT FROM AUTHOR]
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- 2015
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209. Mechanisms of homocysteine neurotoxicity in neurodegenerative diseases with special reference to dementia
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Obeid, Rima, primary and Herrmann, Wolfgang, additional
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- 2006
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210. The Cobalamin-Binding Proteins Transcobalamin and Haptocorrin in Maternal and Cord Blood Sera at Birth
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Obeid, Rima, primary, Morkbak, Anne L, primary, Munz, Winfried, primary, Nexo, Ebba, primary, and Herrmann, Wolfgang, primary
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- 2006
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211. Cognitive decline correlates with low plasma concentrations of copper in patients with mild to moderate Alzheimer's disease
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Pajonk, Frank-Gerald, primary, Kessler, Holger, additional, Supprian, Tillmann, additional, Hamzei, Pegah, additional, Bach, Daniela, additional, Schweickhardt, Janina, additional, Herrmann, Wolfgang, additional, Obeid, Rima, additional, Simons, Andreas, additional, Falkai, Peter, additional, Multhaup, Gerd, additional, and Bayer, Thomas A., additional
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- 2005
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212. Biochemical indexes of the B vitamins in cord serum are predicted by maternal B vitamin status
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Obeid, Rima, primary, Munz, Winfried, additional, Jäger, Monika, additional, Schmidt, Werner, additional, and Herrmann, Wolfgang, additional
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- 2005
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213. Disturbed Homocysteine and Methionine Cycle Intermediates S-Adenosylhomocysteine and S-Adenosylmethionine Are Related to Degree of Renal Insufficiency in Type 2 Diabetes
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Herrmann, Wolfgang, primary, Schorr, Heike, primary, Obeid, Rima, primary, Makowski, Julia, primary, Fowler, Brian, primary, and Kuhlmann, Martin K, primary
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- 2005
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214. The Usefulness of Holotranscobalamin in Predicting Vitamin B12 Status in Different Clinical Settings
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Herrmann, Wolfgang, primary, Obeid, Rima, additional, Schorr, Heike, additional, and Geisel, Jurgen, additional
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- 2005
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215. Cellular Uptake of Vitamin B12 in Patients with Chronic Renal Failure
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Obeid, Rima, primary, Kuhlmann, Martin, additional, Kirsch, Carl-Martin, additional, and Herrmann, Wolfgang, additional
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- 2005
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216. Response of Homocysteine, Cystathionine, and Methylmalonic Acid to Vitamin Treatment in Dialysis Patients
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Obeid, Rima, primary, Kuhlmann, Martin K, primary, Köhler, Hans, primary, and Herrmann, Wolfgang, primary
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- 2005
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217. Vitamin B12 Status in the Elderly as Judged by Available Biochemical Markers
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Obeid, Rima, primary, Schorr, Heike, primary, Eckert, Rudolf, primary, and Herrmann, Wolfgang, primary
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- 2004
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218. Cobalamin Deficiency.
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Herrmann, Wolfgang and Obeid, Rima
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- 2012
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219. Hyperhomocysteinemia and vitamin B-12 deficiency are more striking in Syrians than in Germans—causes and implications
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Herrmann, Wolfgang, primary, Obeid, Rima, additional, and Jouma, Muhidien, additional
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- 2003
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220. Cobalamin Status (Holo-Transcobalamin, Methylmalonic Acid) and Folate as Determinants of Homocysteine Concentration
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Obeid, Rima, primary, Jouma, Muhidien, primary, and Herrmann, Wolfgang, primary
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- 2002
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221. An exploratory study on the effect of choline and folate deficiency on levels of vascularization proteins and transcription factors in first trimester trophoblast HTR‐8/SVneo cells.
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Engelhart, Karin, Pfitzner, Inka, and Obeid, Rima
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BLASTOCYST , *PREGNANCY proteins , *PROTEINS , *RESEARCH , *FOLIC acid deficiency , *FIRST trimester of pregnancy , *VITAMIN B deficiency , *PLACENTA , *RESEARCH funding , *ENZYME-linked immunosorbent assay , *DESCRIPTIVE statistics , *TRANSCRIPTION factors , *CELL lines - Abstract
Aims: We studied the effect of choline and folate deficiencies on levels of predetermined placental proteins during early development. Methods: We incubated HTR‐8/SVneo cells under choline and folate deficiency conditions and measured levels of some placental proteins using ELISA methods. Results: Concentrations of LRP2 protein in cell lysates were higher in cells incubated in choline and folate deficient media compared to the control media (mean [SD] = 2.95 [1.30] vs. 1.65 [0.27] ng/mg protein, p = 0.004). The levels of LRP2 protein in lysates of cells incubated in choline and folate deficient media were significantly higher than the concentrations in lysates of cells incubated in choline deficient but folate sufficient media (1.96 [0.28] ng/mg protein) or those incubated in choline sufficient but folate deficient media (1.77 [0.24] ng/mg protein) (p < 0.05 for both). The cellular levels of CDX2 protein were significantly higher in cells incubated in choline and folate deficient media compared to the control media (1.78 [0.60] vs. 0.99 [0.42] pg/mg protein, p = 0.002); and compared to CDX2 levels in cells incubated in choline deficient but folate sufficient media (0.87 [0.13] pg/mg protein, p < 0.001) or in choline sufficient but folate deficient media (0.96 [0.16] pg/mg protein, p < 0.001). The levels of sFLT‐1 and IGF1 in culture media and that of EOMES in HTR‐8/SVneo cell lysates remained unchanged under all deficiency conditions. Discussion: LRP2 and CDX2 are likely to be molecular targets for early choline and folate deficiencies in human trophoblast cells. The results should be confirmed in animal models and in other models of placental cells. [ABSTRACT FROM AUTHOR]
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- 2023
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222. Critical evaluation of lowering the recommended dietary intake of folate.
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Obeid, Rima, Koletzko, Berthold, and Pietrzik, Klaus
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Summary: We evaluated the recommendation of the Austrian, German, and Swiss Societies for Nutrition of lowering dietary folate intake from 400 to 300 μg dietary folate equivalents/d. A dose–response relation exists between folate intake or plasma level and disease risk within the normal range. Improving folate status can prevent between 30% and 75% of neural tube defects. A prepregnancy plasma folate of >18.0 nmol/L (mean 26.1 nmol/L) is associated with low total homocysteine (tHcy) (<10.0 μmol/L) and optimal prevention of birth defects. Because the closure of the neural tube occurs in the first 8 weeks after conception, women with low prepregnancy folate intake cannot achieve maximal risk reduction. The Austrian, German, and Swiss Societies for Nutrition recommend that young women should additionally supplement with 400 μg folic acid at least 4 weeks before conception. This short time window is not sufficient to achieve optimal plasma folate and tHcy levels in the majority of women. Factors affecting the relation between folate intake and blood biomarkers are total folate intake, baseline plasma folate, time available for supplement use, dose and form (folic acid or methyl folate), genetic polymorphisms, physiological and lifestyle factors. Lowering the recommended dietary folate intake may have important public health consequences. Elderly people and young women are at risk for diseases related to folate shortage. Reducing birth defects through supplementation of folic acid remains a poor option, as <20% of young women (i.e., in Germany) supplement with the vitamin. Recommending adequate food folate intake is crucial for reaching the target protective plasma folate levels in the population. [Copyright &y& Elsevier]
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- 2014
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223. Is 5-methyltetrahydrofolate an alternative to folic acid for the prevention of neural tube defects?
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Obeid, Rima, Holzgreve, Wolfgang, and Pietrzik, Klaus
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NEURAL tube defect prevention , *FOLIC acid metabolism , *BIOMARKERS , *CORD blood , *FOLIC acid , *HOMEOSTASIS , *NEURAL tube defects - Abstract
Women have higher requirements for folate during pregnancy. An optimal folate status must be achieved before conception and in the first trimester when the neural tube closes. Low maternal folate status is causally related to neural tube defects (NTDs). Many NTDs can be prevented by increasing maternal folate intake in the preconceptional period. Dietary folate is protective, but recommending increasing folate intake is ineffective on a population level particularly during periods of high demands. This is because the recommendations are often not followed or because the bioavailability of food folate is variable. Supplemental folate [folic acid (FA) or 5-methyltetrahydrofolate (5-methylTHF)] can effectively increase folate concentrations to the level that is considered to be protective. FA is a synthetic compound that has no biological functions unless it is reduced to dihydrofolate and tetrahydrofolate. Unmetabolized FA appears in the circulation at doses of >200 μg. Individuals show wide variations in their ability to reduce FA. Carriers of certain polymorphisms in genes related to folate metabolism or absorption can better benefit from 5-methylTHF instead of FA. 5-MethylTHF [also known as (6 S)-5-methylTHF] is the predominant natural form that is readily available for transport and metabolism. In contrast to FA, 5-methylTHF has no tolerable upper intake level and does not mask vitamin B12 deficiency. Supplementation of the natural form, 5-methylTHF, is a better alternative to supplementation of FA, especially in countries not applying a fortification program. Supplemental 5-methylTHF can effectively improve folate biomarkers in young women in early pregnancy in order to prevent NTDs. [ABSTRACT FROM AUTHOR]
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- 2013
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224. Elevated dimethylglycine in blood of children with congenital heart defects and their mothers.
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Alsayed, Ranwa, AL Quobaili, Faizeh, Srour, Samir, Geisel, Jürgen, and Obeid, Rima
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CONGENITAL heart disease ,JUVENILE diseases ,DEFICIENCY diseases ,MALNUTRITION ,METHYLATION ,BETAINE-homocysteine methyltransferase ,BIOMARKERS ,BLOOD plasma - Abstract
Abstract: Objective: Congenital Heart Defects (CHD) may be related to nutritional deficiencies affecting the methylation cycle. We aimed to study the metabolic markers of the betaine homocysteine methyl transferase (BHMT) pathway in children with CHD and their mothers compared to children without CHD and their mothers. Materials and Methods: Children with CHD (n=105, age < 3years) and mothers of 80 of the affected children were studied. The controls were non-CHDs children of comparable age as the CHD group (n=52) and their mothers (n=50). We measured serum or plasma concentrations of the metabolites of the methylation cycle homocysteine (HCY), methylmalonic acid (MMA), cystathionine, S-adenosylmethionine (SAM), S-adenosylhomocysteine (SAH), betaine, choline, and dimethylglycine (DMG). Results: Children with CHD had higher plasma SAM (131 vs. 100nmol/L) and DMG (8.7 vs. 6.0μmol/L) and lower betaine/DMG ratio (7.5 vs. 10.2) compared to the controls. Mothers of CHD children showed also higher DMG (6.1 vs. 4.1 µmol/L) and lower betaine/DMG ratio compared with the mothers of the controls. Higher SAM levels were related to higher cystathionine, MMA, betaine, choline, and DMG. MMA elevation in the patients was related to higher HCY, SAM, betaine and DMG. Conclusions: Elevated DMG in CHD children and their mothers compared to the controls can indicate upregulation of the BHMT pathway in this disease group. Nutritional factors are related to metabolic imbalance during pregnancy that may be related to worse birth outcome. [Copyright &y& Elsevier]
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- 2013
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225. Utility and limitations of biochemical markers of vitamin B12 deficiency.
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Herrmann, Wolfgang and Obeid, Rima
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BIOMARKERS , *VITAMIN B12 deficiency , *METHYLMALONIC acid , *TRANSCOBALAMINS , *CREATININE , *DIAGNOSTIC examinations - Abstract
Background There is an urgent need for proper utilization of laboratory markers to diagnose vitamin B12 deficiency that should reduce false negative cases. We worked out a diagnostic algorithm that provides a two-step detection of vitamin B12 deficiency using holotranscobalamin as a first line marker and methylmalonic acid (MMA) as a second line marker. Materials and Methods We tested 1359 serum samples sent to our laboratory for total vitamin B12 assay. Serum samples were used for the determination of holotranscobalamin, MMA and creatinine. Results Compared with total B12, holotranscobalamin showed a higher area under the receiver operating characteristic curve for detecting MMA levels > 300 nM. However, the distribution of holotranscobalamin in individuals with elevated creatinine irrespective of MMA and in individuals with elevated MMA irrespective of creatinine was shifted into the higher ranges. In the grey zone of holotranscobalamin between 23 and 75 pM (the range extending from the 90% diagnostic sensitivity to the 90% diagnostic specificity), MMA testing as a second line marker would help detecting 18% of deficient cases. Lowering MMA after vitamin B12 treatment may help setting the diagnosis of B12 deficiency in individuals with elevated creatinine. Discussion Testing for vitamin B12 deficiency should start with holotranscobalamin measurement. Holotranscobalamin between 23 and 75 pM should be followed by MMA testing that can filter substantial number of deficient cases in the grey range in individuals with normal renal function. This diagnostic strategy may significantly improve assessing vitamin B12 deficiency. [ABSTRACT FROM AUTHOR]
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- 2013
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226. Aqueous humor glycation marker and plasma homocysteine in macular degeneration.
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Obeid, Rima, Ninios, Kouris, Loew, Ursula, Gatzioufas, Zisis, Hoffmann, Stephan, Seitz, Berthold, Geisel, Jurgen, and Herrmann, Wolfgang
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AQUEOUS humor , *HOMOCYSTEINE , *RETINAL degeneration , *METHYLATION , *BLOOD sampling - Abstract
Background: We investigated concentrations of total homocysteine (tHcy) in elderly people without and those with age-related macular degeneration (AMD). In addition, we tested the association between plasma tHcy and one glycation marker in aqueous humor. Methods: People with cataract only (n=48), patients with dry AMD (n=38) and those with wet AMD (n=31) were studied. Blood concentrations of tHcy, and methylation and vitamin markers were measured in 116 blood samples. The concentrations of the extracellular soluble receptor for advanced glycated end products (esRAGE) were measured in 77 aqueous humor samples. Results: Mean aqueous humor concentration of esRAGE and that of plasma tHcy did not differ significantly between the groups. Arterial hypertension but not eye disease explained the tHcy elevation in plasma in this study. In the cataract group, a significant negative correlation was found between plasma tHcy and that of esRAGE in aqueous humor (r=-0.483, p=0.006). In patients with dry AMD, the concentration of esRAGE in aqueous humor correlated negatively to tHcy and positively to serum folate. Conclusions: Plasma tHcy levels were positively associated with hypertension, but not with AMD in this study. Higher esRAGE in aqueous humor was related to higher folate and lower tHcy in blood. Following studies may assess whether B-vitamins can protect against age-related ocular diseases by reducing glycation. [ABSTRACT FROM AUTHOR]
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- 2013
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227. One year B and D vitamins supplementation improves metabolic bone markers.
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Herrmann, Wolfgang, Kirsch, Susanne H., Kruse, Vera, Eckert, Rudolf, Gräber, Stefan, Geisel, Jürgen, and Obeid, Rima
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VITAMIN D deficiency ,VITAMIN B deficiency ,OSTEOPOROSIS ,CALCIUM carbonate ,DISEASE risk factors ,DIETARY supplements - Abstract
Background: Vitamin D and vitamin B deficiency are common in elderly subjects and are important risk factors for osteoporosis and age-related diseases. Supplementation with these vitamins is a promising preventative strategy. The objective of this study was to evaluate the effects of vitamins D3 and B supplementation on bone turnover and metabolism in elderly people. Methods: Healthy subjects (n=93; >54 years) were randomly assigned to receive either daily vitamin D3 (1200 IU), folic acid (0.5 mg), vitamin B12 (0.5 mg), vitamin B6 (50 mg), and calcium carbonate (456 mg) (group A) or only vitamin D3 plus calcium carbonate (group B) in a double blind trial. We measured at baseline and after 6 and 12 months of supplementation vitamins, metabolites, and bone turnover markers. Results: At baseline mean plasma 25-hydroxy vitamin D [25(OH)D] was low (40 or 30 nmol/L) and parathormone was high (63.7 or 77.9 pg/mL). 25(OH)D and parathormone correlated inversely. S-Adenosyl homocysteine and S-adenosyl methionine correlated with bone alkaline phosphatase, sclerostin, and parathormone. One year vitamin D3 or D3 and B supplementation increased plasma 25(OH)D by median 87.6% (group A) and 133.3% (group B). Parathormone was lowered by median 28.3% (A) and 41.2% (B), bone alkaline phosphatase decreased by 2.8% (A) and 16.2% (B), osteocalin by 37.5% (A) and 49.4% (B), and tartrate-resistant-acid-phosphatase 5b by 6.1% (A) and 36.0% (B). Median total homocysteine (tHcy) was high at baseline (group A: 12.6, group B: 12.3 µmol/L) and decreased by B vitamins (group A) to 8.9 µmol/L (29.4%). tHcy lowering had no additional effect on bone turnover. Conclusions: One year vitamin D3 supplementation with or without B vitamins decreased the bone turnover significantly. Vitamin D3 lowered parathormone. The additional application of B vitamins did not further improve bone turnover. The marked tHcy lowering by B vitamins may modulate the osteoporotic risk. [ABSTRACT FROM AUTHOR]
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- 2013
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228. Effect of 1 year B and D vitamin supplementation on LINE-1 repetitive element methylation in older subjects.
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Hübner, Ulrich, Geisel, Jürgen, Kirsch, Susanne H., Kruse, Vera, Bodis, Marion, Klein, Cosima, Herrmann, Wolfgang, and Obeid, Rima
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VITAMIN B deficiency ,VITAMIN D deficiency ,DNA methylation ,ADENOSYLMETHIONINE ,HOMOCYSTEINE ,DIETARY supplements - Abstract
Background: Disturbed DNA methylation is causally related to chronic diseases like cancer and atherosclerosis. B vitamins are cofactors required for methyl group synthesis and may therefore affect DNA methylation. Vitamin D has epigenetic effects. We tested if B and D vitamin supplementation has an effect on genomic long interspersed nuclear element-1 (LINE-1) methylation and the metabolites S-adenosylmethionine (SAM) and S-adenosylhomocysteine (SAH). Methods: Fifty subjects (median age 68.0 years) were supplemented with a daily oral dose of B vitamins (500 µg folic acid, 500 µg vitamin B12 and 50 mg vitamin B6), 1200 IU vitamin D and 456 mg calcium. Fasting blood samples were collected before and after 1 year of supplementation. LINE-1 methylation was determined in genomic DNA from blood cells as a surrogate for whole genome methylation. In addition, SAM, SAH and total homocysteine (tHcy) were measured in plasma samples. Results: Plasma homocysteine decreased significantly after supplementation (12.8 vs. 9.1 µmol/L; p<0.05), whereas SAM, SAH, the SAM/SAH ratio and LINE-1 methylation did not change significantly. LINE-1 methylation was not significantly correlated with SAH, homocysteine or B vitamins. Conclusions: Long-term vitamin B supplementation had no effect on LINE-1 methylation in blood cells nor on plasma levels of SAM and SAH. Vitamin B and D supplementation seems to have no effect on DNA methylation, especially in cases where no severe deficiency exists. [ABSTRACT FROM AUTHOR]
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- 2013
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229. Factors affecting the distribution of folate forms in the serum of elderly German adults.
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Kirsch, Susanne, Herrmann, Wolfgang, Eckert, Rudolf, Geisel, Jürgen, and Obeid, Rima
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FOLIC acid metabolism ,AGE distribution ,ANALYSIS of variance ,CHI-squared test ,FOLIC acid ,GENETIC polymorphisms ,STATISTICS ,T-test (Statistics) ,U-statistics ,VITAMIN B12 ,DATA analysis ,DATA analysis software ,DESCRIPTIVE statistics - Abstract
Purpose: We investigated the roles of age, vitamin B markers, and the 5,10-methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism as determinants of folate forms in serum. Methods: We measured the serum concentrations of (6 S)-5-CH-Hfolate, (6 S)-Hfolate, (6 S)-5-HCO-Hfolate, (6 R)-5,10-CH-Hfolate, and folic acid in 146 non-supplemented older participants (median age 74 years). The concentrations of total vitamin B, holotranscobalamin (holoTC), methylmalonic acid (MMA), and total homocysteine (tHcy) were also measured. Results: Elevated metabolites (MMA > 271 nmol/L and tHcy > 12.0 μmol/L) were found in 24.0 and 63.0 % of the participants, respectively. We found a significant age-dependent decrease (participants with a median age of 87 years compared with participants with a median age of 60 years) in the sum of serum folate levels, the (6 S)-5-CH-Hfolate concentration, and the (6 S)-5-CH-Hfolate proportion. In addition, participants with elevated metabolite levels were older, had lower concentrations of the sum of folates and (6 S)-5-CH-Hfolate, and had higher concentrations of (6 S)-5-CHO-Hfolate and creatinine but had a comparable holoTC/total vitamin B ratio. No association was found between the MTHFR C677T genotype and serum folate forms. Conclusion: Low serum (6 S)-5-CH-Hfolate concentrations and the proportion of (6 S)-5-CH-Hfolate (percentage of the sum of folate forms) are related to older age and elevated MMA and tHcy levels. [ABSTRACT FROM AUTHOR]
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- 2013
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230. Genetic defects in folate and cobalamin pathways affecting the brain.
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Kirsch, Susanne H., Herrmann, Wolfgang, and Obeid, Rima
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FOLIC acid deficiency ,VITAMIN B12 ,NEURAL development ,NEUROLOGICAL disorders ,DISEASE management ,METHYLMALONIC acid - Abstract
Folate and cobalamin are necessary for early brain development and function. Deficiency of folate or cobalamin during pregnancy can cause severe malformation in the central nervous system such as neural tube defects. After birth, folate and cobalamin deficiency can cause anemia, failure to thrive, recurrent infections, psychiatric and neurological symptoms. The folate and the homocysteine metabolic pathways interact at a central step where 5-methyltetrahydrofolate donates its methyl group to homocysteine to produce methionine and tetrahydrofolate. Methyl cobalamin and folate interact at this critical step. Both nutrients have a crucial role in DNA synthesis and in delivering S-adenosylmethionine, the universal methyl donor. Severe and mild inherited disorders in folate and cobalamin pathways have been described. The two groups of disorders share some similarities, but differ in the molecular mechanism, metabolic dysregulation, and disease management. This review summarizes selected disorders, including rare and common mutations that affect folate and cobalamin absorption, transport, or dependent enzymes. When the mutations are discovered early enough, many of the described disorders are easily treatable by B vitamin supplementation, which often prevents or reverses the manifestation of the disease. Therefore, the screening for mutations is recommended and should be carried out as early as possible: after occurrence of the first symptoms or when a certain constellations of the folate and cobalamin related markers are measured, such as elevated homocysteine and/or methylmalonic acid. [ABSTRACT FROM AUTHOR]
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- 2013
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231. Assay of whole blood (6 S)-5-CH-Hfolate using ultra performance liquid chromatography tandem mass spectrometry.
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Kirsch, Susanne, Herrmann, Wolfgang, Geisel, Jürgen, and Obeid, Rima
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FOLIC acid ,DNA ,SERUM ,ANTIOXIDANTS ,LIQUID chromatography-mass spectrometry - Abstract
Folates act as essential coenzymes in many biological pathways, including the synthesis and methylation of DNA. Low folate concentration in serum and whole blood (WB) is associated with several disease conditions. We describe a stable-isotope-dilution ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method for the quantification of (6 S)-5-CH-Hfolate (where Hfolate is tetrahydrofolate) and non-CH-Hfolate [sum of HCO-Hfolate, (6 R)-5,10-CH-Hfolate, (6 R)-5,10-CH-Hfolate, (6 S)-Hfolate, dihydrofolate, and folic acid] in WB. The assay includes a solid-phase extraction procedure after the hemolysis and deconjugation. The method was linear over the concentration range from 0.2 to 200 nmol/L. The limits of detection were 0.40 nmol/L or lower for the folate forms. The interassay coefficients of variation were 7.4 % for (6 S)-5-CH-Hfolate and 15.4 % for non-CH-Hfolate. For the folate forms, the recoveries were between 97.1 % and 102.7 %. Sample preparation caused the generation of artificial folic acid in WB and serum in a dose-dependent manner, which can lead to misinterpretation of the results. The use of antioxidants could not prevent the formation of folic acid. The median fasting WB folate concentrations from 42 nonsupplemented and nonfortified adults were 576 nmol/L (6 S)-5-CH-Hfolate and 73.6 nmol/L non-CH-Hfolate, and 1,206 nmol/L (6 S)-5-CH-Hfolate and 155 nmol/L non-CH-Hfolate for 35 adults who had taken 500 μg of folic acid, 50 mg of vitamin B, and 500 μg of vitamin B per day orally for 6 months. In conclusion, the UPLC-MS/MS method is fast and has a good sensitivity and selectivity for WB folates. We observed a dose-dependent oxidation of (6 S)-Hfolate, which resulted in the formation of artificial folic acid in serum and WB. To minimize this effect, we recommend a fast sample preparation. [ABSTRACT FROM AUTHOR]
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- 2012
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232. Blood biomarkers of methylation in Down syndrome and metabolic simulations using a mathematical model.
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Obeid, Rima, Hartmuth, Kathrin, Herrmann, Wolfgang, Gortner, Ludwig, Rohrer, Tilman R., Geisel, Jürgen, Reed, Michael C., and Nijhout, H. Frederik
- Published
- 2012
- Full Text
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233. Methylation capacity in children with severe cerebral palsy.
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Schoendorfer, Niikee C., Obeid, Rima, Moxon-Lester, Leith, Sharp, Nita, Vitetta, Luis, Boyd, Roslyn N., and Davies, Peter S. W.
- Subjects
- *
CEREBRAL palsy treatment , *METHYLATION , *CARBON metabolism , *DNA synthesis , *GASTROSTOMY , *METHYLMALONIC acid , *CELL size , *HOMOCYSTEINE - Abstract
Eur J Clin Invest 2012; 42 (7): 768-776 Abstract Background Methylation cycle and folate-mediated one-carbon metabolism maintenance is important for many physiological processes including neurotransmitter regulation, nerve myelination and DNA synthesis. These processes play an indispensible role in growth and development, as well as in cognitive function and neuromuscular stability, which are key issues in children with severe cerebral palsy (CP). Methods Blood samples were collected from children with severe CP ( n = 24) and age-matched typically developing healthy controls ( n = 24), as an exploratory study. The CP group was divided into orally (O) or enterally fed via percutaneous endoscopic gastrostomy (E). Concentrations of red cell folate (RCF), methylmalonic acid (MMA), mean cell volume (MCV), homocysteine (Hcy), cystathionine, choline, betaine and urate were assayed. Results Homocysteine was increased in both O mean (±SD) = 6·28 (±1·81 μM) and E = 6·03 (±1·28), vs. controls = 5·07 (±0·98) P = 0·02. Higher MMA was found in controls = 157 (±54) and O = 141 (±101), vs. E = 88(±21) P = 0·05. RCF was higher in E = 1422 (±70 nM) vs. O = 843 (±80) and controls = 820 (±43) P < 0·001. MCV z-scores were elevated in E = 3·1 (±1·8) and O = 1·1 (±1·1) compared with controls = −0·2 (±1·1) P < 0·001. Urate was significantly reduced in O = −0·64 (±1·38) and E = −0·87 (±0·71), vs. controls = 0·18 (±0·62) P = 0·006. Conclusions Raised MCV in the presence of elevated red cell folate, adequate B12 status and low plasma urate suggest potential methyltetrahydrofolate trapping and impaired purine synthesis. Well-documented malnutrition issues in O may explain differences between CP groups. These data support the hypothesis of possible dysregulation in methylation capacity and/or folate one-carbon metabolism, although more research is needed to elucidate a precise mechanism. [ABSTRACT FROM AUTHOR]
- Published
- 2012
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234. Quantification of plasma phospholipids by ultra performance liquid chromatography tandem mass spectrometry.
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Rabagny, Yannick, Herrmann, Wolfgang, Geisel, Jürgen, Kirsch, Susanne, and Obeid, Rima
- Subjects
LIQUID chromatography ,TANDEM mass spectrometry ,PHOSPHOLIPIDS ,REGRESSION analysis ,LECITHIN - Abstract
We describe a fast and robust ultra performance liquid chromatography tandem mass spectrometry method for the quantification of phospholipid (PL) species in EDTA-plasma samples. We quantified total phosphatidylcholine (PC), phosphatidylethanolamine (PE), lysophosphatidylcholine (LPC), and sphingomyelin (SM) and several species within these classes using one or two external calibrators and one internal standard for each class. Inter-assay coefficients of variation were <10% for the most abundant species and <20% for all quantified PC, LPC, and SM species and the three most abundant PE species. Coefficients of linear regression were R > 0.98. Mean recoveries were between 83% and 123%. The limits of detection were 0.37 μmol/L for PC, 4.02 μmol/L for LPC, 3.75 μmol/L for PE, and 0.86 μmol/L for SM. Quantification was linear over the physiological ranges for PE, LPC, and SM and up to 500 μmol/L for PC. The concentrations of PLs in the plasma of healthy donors yielded results that were comparable with those of previous works. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
235. Advanced glycation end products overload might explain intracellular cobalamin deficiency in renal dysfunction, diabetes and aging.
- Author
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Obeid, Rima, Shannan, Batool, and Herrmann, Wolfgang
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GLYCOSYLATION ,VITAMIN B12 deficiency ,KIDNEY diseases ,DIABETES ,AGING ,CELL growth ,DISEASE complications ,KIDNEY tubules - Abstract
Abstract: Advanced glycation end products (AGEs) contribute to aging. Cobalamin (Cbl) is required for cell growth and functions, and its deficiency causes serious complications. Diabetics and renal patients show high concentrations of Cbl, but metabolic evidence of Cbl deficiency that is reversible after Cbl treatment. Cbl might be sequestered in blood and cannot be delivered to the cell. Megalin mediates the uptake of transcobalamin–Cbl complex into the proximal tubule cells. Megalin is involved in the uptake and degradation of AGEs. In aging, diabetes or renal dysfunction, AGEs might overload megalin thus lowering Cbl uptake. Transcobalamin–Cbl might retain in blood. Shedding of megalin and transcobalamin receptor under glycation conditions is also a possible mechanism of this phenomenon. [Copyright &y& Elsevier]
- Published
- 2011
- Full Text
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236. Trefoil factor family peptides in the human foetus and at birth.
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Samson, Mie H., Poulsen, Steen S., Obeid, Rima, Herrmann, Wolfgang, and Nexo, Ebba
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PEPTIDES ,SULFUR amino acids ,BLOOD proteins ,MUCOUS membranes ,FETAL tissues ,PLACENTA - Abstract
Background Trefoil factors (TFF1-3) are cysteine-rich peptides secreted by mucosal surfaces. Changing levels of expression are reflected in serum concentrations. Serum levels of TFF2 and TFF3 are highly elevated during pregnancy. Here, we explore a possible foetal origin of these increased levels. Materials and methods We examined the expression of trefoil peptides in foetal tissues, placentas and foetal membranes from midterm abortions by immunohistochemistry. Employing in-house ELISAs, serum concentrations of TFF1-3 were measured in 92 paired samples of cord and maternal blood prior to delivery. Size exclusion chromatography was used to investigate the molecular forms of TFF1-3. Results Immunohistochemistry showed all trefoil peptides to be present during foetal life, but compared to adults with a more widespread expression of TFF2 and TFF3 in the stomach and Brunner's glands. No trefoil peptides were seen in placentas or foetal membranes. Median serum concentrations of TFF1 in cord blood were comparable to those observed in the (mother) [0·42 (0·37) nM, P = 0·25], whereas TFF2 and TFF3 showed lower values than in the mother [0·11 (0·69), and 1·2 (6·7) nM, respectively, P < 0·0001 for both peptides]. Size exclusion chromatography showed comparable patterns in mothers and newborns. Conclusions All three trefoil peptides are expressed in foetal tissues but not in placenta or foetal membranes. Cord blood contains high levels of all three peptides, although for TFF2 and TFF3 at considerably lower levels than observed in the mother. Thus, the elevated serum levels of TFF2 and TFF3 in the pregnant women were most likely not of foetal origin. [ABSTRACT FROM AUTHOR]
- Published
- 2011
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- View/download PDF
237. Folate is related to phosphorylated neurofilament-H and P-tau (Ser396) in rat brain.
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Obeid, Rima, Schlundt, Jennifer, Umanskaya, Natalia, Herrmann, Wolfgang, and Herrmann, Markus
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- *
HYPERHOMOCYSTEINEMIA , *PHOSPHORYLATION , *CYTOPLASMIC filaments , *PHOSPHOPROTEIN phosphatases , *ALZHEIMER'S disease prevention , *PHYSIOLOGY - Abstract
The article presents a research study on the effect of hyperhomocysteinemia on phosphorylated tau, neurofilaments, and protein phosphatase PP2A activity in rat brains. The author explains that phosphorylated neurofilament heavy chain is a constituent of aggregates in the brains of Alzheimers patients, and that factors that lower the phosphorylation may be used to prevent Alzheimers Disease.
- Published
- 2011
- Full Text
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238. Concentrations of unmetabolized folic acid and primary folate forms in plasma after folic acid treatment in older adults.
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Obeid, Rima, Kirsch, Susanne H., Kasoha, Mariz, Eckert, Rudolf, and Herrmann, Wolfgang
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FOLIC acid ,VITAMIN B complex ,BLOOD plasma ,VITAMIN B12 ,PLACEBOS ,PUBLIC health ,PREVENTIVE medicine - Abstract
Abstract: Folate deficiency can cause age-related disease. Folic acid (FA) has been used in studies aiming at disease prevention. Recently, unmetabolized FA in plasma raised public health concerns; but numerous studies used FA for disease prevention. Concentrations of the folate forms FA, 5-methyltetrahydrofolate (5-MTHF), and tetrahydrofolate (THF) were measured before and after 3-week placebo or FA 5 mg, vitamin B6 40 mg, and cyanocobalamin 2 mg per day administrated to 74 older adults (median age, 82 years). Concentrations of 5-MTHF and total homocysteine (tHcy) (r = −0.392) and S-adenosylmethionine (r = 0.329) were correlated at baseline. Twenty-six percent of the elderly subjects had unmetabolized FA in plasma at the start, and concentrations of FA were increased after 3 weeks of FA treatment (median FA = 0.08 nmol/L at baseline and 15.3 nmol/L at the end of the treatment in the vitamin group). Folic acid caused a 10- and a 5-fold increase in 5-MTHF and THF, respectively, and lowered tHcy (median tHcy = 17.2 μmol/L at baseline vs 9.0 μmol/L after treatment). Concentrations of unmetabolized FA were positively related to those of 5-MTHF and THF. People showed wide variations in folate forms at baseline, but these were reduced after FA treatment. Folic acid given to older adults is mostly converted to THF and 5-MTHF and lowered concentrations of tHcy, but caused a substantial increase in unmetabolized FA in the plasma. [Copyright &y& Elsevier]
- Published
- 2011
- Full Text
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239. Homocysteine: a biomarker in neurodegenerative diseases.
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Herrmann, Wolfgang and Obeid, Rima
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- *
NEURODEGENERATION , *HOMOCYSTEINE , *BIOMARKERS , *ALZHEIMER'S disease , *VITAMIN B deficiency - Abstract
Diseases of the central nervous system are found in patients with severe hyperhomocysteinemia (HHcy). Epidemiological studies show a positive, dose-dependent relationship between mild-to-moderate increases in plasma total homocysteine concentrations (Hcy) and the risk of neurodegenerative diseases, such as Alzheimer's disease, vascular dementia, cognitive impairment or stroke. HHcy is a surrogate marker for B vitamin deficiency (folate, B12, B6) and a neurotoxic agent. The concept of improving the patient's clinical outcome by lowering of Hcy with B vitamins seems to be attractive. Recent B vitamin supplementation trials demonstrated a slowing of brain atrophy and improvement in some domains of cognitive function. Meta-analysis of secondary prevention trials showed that B vitamins supplementation caused a decrease in plasma Hcy and a trend for lowering the risk of stroke. HHcy is common in elderly people. Therefore, it seems prudent to identify B vitamin deficient subjects and to ensure sufficient vitamin intake. Therefore, recent evidence supports the role of Hcy as a potential biomarker in age-related neurodegenerative diseases. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
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240. Homocysteine in small-for-gestational age and appropriate-for-gestational age preterm neonates from mothers receiving folic acid supplementation.
- Author
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Gomes, Thushari S., Lindner, Ulrike, Tennekoon, Kamani H., Karandagoda, Wimal, Gortner, Ludwig, and Obeid, Rima
- Subjects
HOMOCYSTEINE ,GESTATIONAL age ,NEWBORN infants ,FOLIC acid deficiency ,BIRTH weight ,FOLIC acid - Abstract
Background: Prematurity and small-for-gestational age (SGA) neonates are at risk for postnatal complications. Concentrations of total homocysteine (tHcy) might be related to neonatal outcome. We hypothesized that concentrations of tHcy are not related to growth restriction in neonates from mothers receiving 5 mg/day folic acid. We studied a total of 133 preterm neonates from normotensive mothers; SGA (n=96) and appropriate-for-gestational age (AGA, n=37). Methods: Concentrations of tHcy, folate and vitamin B12 were measured in venous umbilical cord plasma. Results: AGA preterm neonates had higher mean birth weight (BW) compared to SGA preterms (2472 g vs. 2007 g; p<0.001) of comparable mean gestational age (GA) (35.1 vs. 35.7 weeks; p=0.059). Concentrations of tHcy (4.86 vs. 4.95 μmol/L), folate (63.3 vs. 55.7 nmol/L), and vitamin B12 (409 vs. 394 pmol/L) were not significantly different between the groups. GA was a strong positive predictor, BW was a significant negative predictor of cord plasma folate. Vitamin B12 concentration was a significant negative predictor of cord tHcy. Conclusions: Concentrations of tHcy did not differ between SGA and AGA preterm neonates born to mothers supplemented with folic acid. This finding argues against a causal role for folate deficiency or increased tHcy in growth restriction. Clin Chem Lab Med 2010;48:1157–61. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
241. Enhanced bone metabolism in vegetarians – the role of vitamin B12 deficiency.
- Author
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Herrmann, Wolfgang, Obeid, Rima, Schorr, Heike, Hübner, Ulrich, Geisel, Jürgen, Sand-Hill, Marga, Ali, Nayyar, and Herrmann, Markus
- Subjects
- *
BONE metabolism , *VITAMIN B12 deficiency , *BONE injuries , *VEGETARIANS , *BLOOD testing , *HOMOCYSTEINE , *FOLIC acid deficiency , *ALKALINE phosphatase , *DISEASES - Abstract
Background: Vitamin B12 deficiency and bone fractures are common in vegetarians. However, a direct relationship between vitamin B12 status and bone metabolism in vegetarians has not been tested sufficiently. Methods: Our study included 96 vegetarians (23 German vegans, and 54 German and 19 Indian lacto-, lacto-ovo-vegetarians) and 89 omnivores (Germans and Asian-Indian immigrants in Oman). Blood concentrations of total vitamin B12, holotranscobalamin (holoTC), 25OH-vitamin D (25(OH)D), total homocysteine (tHcy), methylmalonic acid (MMA), and the bone turnover markers (BTMs) bone alkaline phosphatase (BAP), osteocalcin (OC), pro-collagen type I N-terminal peptide (PINP) and C-terminal telopeptides of collagen I (CTx) were measured. Results: Vegetarians from both population groups exhibited significantly higher concentrations of tHcy, MMA, folate, and BAP, but lower concentrations of holoTC and cobalamin compared with omnivores from the same population. Additionally, German vegetarians had higher circulating activities of BAP as well as higher CTx, OC, and PINP compared with their omnivorous controls. HoloTC and MMA were correlated with OC, CTx and BAP. Subjects with low vitamin B12 status (holoTC ≤35 pmol/L and MMA >271 nmol/L) had significantly lower serum concentrations of 25(OH)D, but higher tHcy and the BTMs P1NP, BAP, OC, and CTx, compared with subjects with normal vitamin B12 status. Multiple regression analysis showed that the association between BTMs and markers of vitamin B12 status was independent from the association with 25(OH)D. Approximately 12%–14% of the variation in the concentration of BTMs was explained by a regression model including holoTC, MMA and 25(OH)D. The strictness of the diet was not related to the magnitude of change in BTMs. Conclusions: Low vitamin B12 status is related to increased bone turnover in vegetarians which is independent from vitamin D status. Clin Chem Lab Med 2009;47:1381–7. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
- View/download PDF
242. Homocysteine and lipids: S-Adenosyl methionine as a key intermediate
- Author
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Obeid, Rima and Herrmann, Wolfgang
- Subjects
- *
CLINICAL chemistry , *HOMOCYSTEINE , *LIPIDS , *HYPERLIPIDEMIA , *HIGH density lipoproteins , *ADENOSYLMETHIONINE , *VASCULAR diseases , *METABOLIC syndrome , *PATIENTS , *DISEASE risk factors - Abstract
Abstract: An association between hyperlipidemia and hyperhomocysteinemia (HHCY) has been suggested. This link is clinically important in management of vascular risk factors especially in elderly people and patients with metabolic syndrome. Higher plasma homocysteine (Hcy) was associated with lower high-density lipoprotein (HDL)-cholesterol level. Moreover, HHCY was associated with disturbed plasma lipids or fatty liver. It seems that hypomethylation associated with HHCY is responsible for lipid accumulation in tissues. Decreased methyl group will decrease the synthesis of phosphatidylcholine, a major phospholipid required for very low-density lipoprotein (VLDL) assembly and homeostasis. The effect of Hcy on HDL-cholesterol is probably related to inhibiting enzymes or molecules participating in HDL-particle assembly. [Copyright &y& Elsevier]
- Published
- 2009
- Full Text
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243. Habitual Choline Intakes across the Childbearing Years: A Review.
- Author
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Derbyshire, Emma, Obeid, Rima, and Schön, Christiane
- Abstract
Choline is an important nutrient during the first 1000 days post conception due to its roles in brain function. An increasing number of studies have measured choline intakes at the population level. We collated the evidence focusing on habitual choline intakes in the preconceptual, pregnancy, and lactation life stages. We conducted a review including studies published from 2004 to 2021. Twenty-six relevant publications were identified. After excluding studies with a high choline intake (>400 mg/day; two studies) or low choline intake (<200 mg/day; one study), average choline intake in the remaining 23 studies ranged from 233 mg/day to 383 mg/day, even with the inclusion of choline from supplements. Intakes were not higher in studies among pregnant and lactating women compared with studies in nonpregnant women. To conclude, during the childbearing years and across the globe, habitual intakes of choline from foods alone and foods and supplements combined appear to be consistently lower than the estimated adequate intakes for this target group. Urgent measures are needed to (1) improve the quality of choline data in global food composition databases, (2) encourage the reporting of choline intakes in dietary surveys, (3) raise awareness about the role(s) of choline in foetal–maternal health, and (4) consider formally advocating the use of choline supplements in women planning a pregnancy, pregnant, or lactating. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
244. Biomarkers of folate and vitamin B12 status in cerebrospinal fluid.
- Author
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Herrmann, Wolfgang and Obeid, Rima
- Subjects
- *
VITAMIN B12 , *CEREBROSPINAL fluid , *CEREBROVASCULAR disease , *HOMOCYSTEINE , *VITAMIN deficiency , *METHYLATION - Abstract
Folate and vitamin B12 are essential cofactors for the methionine/homocysteine cycle in the brain. These vitamins mediate the remethylation of homocysteine (Hcy), which affects the production of the universal methyl donor, S-adenosylmethionine (SAM), in the brain among other organs. Additionally, increased plasma concentrations of total Hcy (tHcy) are associated with cerebrovascular disease and can compromise the blood-brain barrier. tHcy concentrations in the brain and cerebrospinal fluid become increased in several psychiatric and neurological disorders. Disturbances in the transmethylation pathway indicated by abnormal SAM, S-adenosylhomocysteine or their ratio have been reported in many neurodegenerative diseases, such as dementia, depression or Parkinson's disease. Cobalamin is essential for neuronal generation and its deficiency can cause degeneration of the nervous system. Available data emphasize that deficiency of folate and vitamin B12 can lead to elevated concentrations of tHcy and disturbed methylation potential in the brain. Therefore, acquired or inherited disorders in these metabolic pathways are associated with brain abnormalities and severe neurological symptoms that are mostly irreversible, even after providing the missing cofactors. This review discusses the relationship between brain and blood levels of key vitamins and metabolites related to one carbon metabolism. Clin Chem Lab Med 2007;45:1614–20. [ABSTRACT FROM AUTHOR]
- Published
- 2007
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245. Homocysteine, folic acid and vitamin B12 in relation to pre- and postnatal health aspects.
- Author
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Obeid, Rima and Herrmann, Wolfgang
- Subjects
- *
VITAMIN deficiency , *DEFICIENCY diseases , *HOMOCYSTEINE , *SULFUR amino acids , *CHILDREN'S health , *THROMBOSIS , *ISOPENTENOIDS , *VITAMIN B complex - Abstract
Studies linking hyperhomocysteinemia (HHCY) and B-vitamin deficiency to some health aspects in children have been accumulating. Low B-vitamin status inearly life, even as early as the time of conception, may endanger the potential for new life and may negatively influence the health of the offspring. Early abortion, pregnancy complications and poor pregnancy outcomes have been linked to elevated concentrations of total plasma homocysteine (tHcy) and low folate or vitamin B12. Maternal vitamin status predicts that of fetuses and neonates. Lactating women are likely to experience low micronutrient status, which might affect breast-milk composition and hence the nutritional status of their breast-fed infants. Elevated concentrations of methylmalonic acid (MMA) is common in infants (age <6 months), which may indicate a transient inadequate vitamin B12 status. Deficiency of B-vitamins might confer deleterious effects on the physical and mental health of the child, such as impaired growth, gross motor function, poor school performance and other adaptive skills. The importance of maintaining adequate B-vitamin status during periods of progressive growth and development should be emphasized because symptoms related to folate and vitamin B12 deficiency are difficult to detect. Serum levels of tHcy and MMA should be estimated in several target groups of children, pregnant and lactating women and those planning for pregnancy. Concentrations of tHcy and MMA are useful indicators of B-vitamin status in the pediatric laboratory. Using these functional markers may facilitate detecting sub-optimal B-vitamin status in children. [ABSTRACT FROM AUTHOR]
- Published
- 2005
- Full Text
- View/download PDF
246. Cellular Uptake of Vitamin B12 in Patients with Chronic Renal Failure.
- Author
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Obeid, Rima, Kuhlmann, Martin, Kirsch, Carl-Martin, and Herrmann, Wolfgang
- Subjects
- *
CHRONIC kidney failure , *VITAMIN B12 , *HOMOCYSTEINE , *CYSTATHIONINE gamma-lyase , *CELLS , *PATIENTS - Abstract
Background/Aims: Elevated concentration of plasma homocysteine (tHcy) is common in renal patients, however, the reason behind the resistance to vitamin B12 and folate therapy are poorly understood. Methods: We investigated vitamin B12 uptake by mononuclear cells (MC) from predialysis patients (n = 19) as compared to healthy controls (n = 15). Serum levels of tHcy, methylmalonic acid and cystathionine, holotranscobalamin (holoTC), total vitamin B12 and folate were also measured. Results: The uptake of vitamin B12 by MC from renal patients was lower than that by MC from controls (9.3 vs. 12.5 pg/3 × 106 cells; p = 0.001). Nonetheless, the receptor-binding capacity was comparable between patients and controls (6.1 vs. 6.5 pg/3 × 106 cells; p = 0.627). Average reduction of vitamin B12 uptake in patients as compared to the controls was 18.1%. Conclusions: Our results show that vitamin B12 uptake is impaired in MC from renal patients, with no evidence that the surface receptor is down-regulated. High serum concentrations of holoTC are common in renal patients and might be related to a generalized resistance to this vitamin. Serum concentrations of vitamin B12 within the reference range are not likely to ensure vitamin delivery into the cells. Supraphysiological doses of vitamin B12 may be necessary to deliver a sufficient amount of the vitamins to the cells via mechanisms largely independent of holoTC receptor. Copyright © 2005 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]
- Published
- 2005
- Full Text
- View/download PDF
247. Stimulatory Effect of Homocysteine on Interleukin-8 Expression in Human Endothelial Cells.
- Author
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Jürgen, Geisel, Jödden, Verena, Obeid, Rima, Knapp, Jean Pierre, Bodis, Marion, and Herrmann, Wolfgang
- Subjects
HOMOCYSTEINE ,ATHEROSCLEROSIS ,MONOCYTES ,CYTOKINES ,GENE expression - Abstract
Elevated plasma homocysteine is an independent risk factor for atherosclerosis. An important initial step of atherosclerosis is the adhesion and infiltration of monocytes to the lesion site. It has been shown that the pro-inflammatory cytokine interleukin-8 can rapidly cause rolling monocytes to adhere firmly onto monolayers expressing E-selectin. The objective of the present study was to investigate the effect of homocysteine on interleukin-8 production in human endothelial cells. Cells were incubated with various concentrations of homocysteine for 20 h. The gene expression was determined by real-time PCR and the interleukin-8 protein was measured by immunoassay analysis. Homocysteine enhanced the expression of interleukin-8 in a dose-dependent manner (181% of controls at 2.5 mmol/l homocysteine). Stimulation of gene expression was associated with a parallel increase in interleukin-8 protein synthesis (160% of controls at 5.0 mmol/l homocysteine). By coincubation of endothelial cells with homocysteine and copper sulfate, a further elevation of interleukin-8 expression (251% of controls) was observed, whereas copper sulfate alone had no stimulatory effect. In conclusion, the present study demonstrated that homocysteine altered endothelial cell function by stimulating interleukin-8 expression, suggesting a contribution of homocysteine to the initiation and progression of atherosclerosis. The formation of homocysteine-induced oxidation products might serve as one of the underlying mechanisms of this effect. [ABSTRACT FROM AUTHOR]
- Published
- 2003
248. Metafolin® - ein neuer Meilenstein in der Weiterentwicklung von Säuglingsnahrungen.
- Author
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Obeid, Rima
- Published
- 2022
249. Liebe Leserinnen, liebe Leser, ...
- Author
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Obeid, Rima
- Published
- 2021
- Full Text
- View/download PDF
250. Cellular Uptake of Vitamin B12in Patients with Chronic Renal Failure
- Author
-
Obeid, Rima, Kuhlmann, Martin, Kirsch, Carl-Martin, and Herrmann, Wolfgang
- Abstract
Background/Aims:Elevated concentration of plasma homocysteine (tHcy) is common in renal patients, however, the reason behind the resistance to vitamin B
12 and folate therapy are poorly understood. Methods:We investigated vitamin B12 uptake by mononuclear cells (MC) from predialysis patients (n = 19) as compared to healthy controls (n = 15). Serum levels of tHcy, methylmalonic acid and cystathionine, holotranscobalamin (holoTC), total vitamin B12 and folate were also measured. Results:The uptake of vitamin B12 by MC from renal patients was lower than that by MC from controls (9.3 vs. 12.5 pg/3 × 106 cells; p = 0.001). Nonetheless, the receptor-binding capacity was comparable between patients and controls (6.1 vs. 6.5 pg/3 × 106 cells; p = 0.627). Average reduction of vitamin B12 uptake in patients as compared to the controls was 18.1%. Conclusions:Our results show that vitamin B12 uptake is impaired in MC from renal patients, with no evidence that the surface receptor is down-regulated. High serum concentrations of holoTC are common in renal patients and might be related to a generalized resistance to this vitamin. Serum concentrations of vitamin B12 within the reference range are not likely to ensure vitamin delivery into the cells. Supraphysiological doses of vitamin B12 may be necessary to deliver a sufficient amount of the vitamins to the cells via mechanisms largely independent of holoTC receptor.- Published
- 2005
- Full Text
- View/download PDF
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