These are representative sample records from Science.gov related to your search topic.
For comprehensive and current results, perform a real-time search at Science.gov.
1

Vitamin b(1) and b(12) uptake and cycling by plankton communities in coastal ecosystems.  

PubMed

While vitamin B(12) has recently been shown to co-limit the growth of coastal phytoplankton assemblages, the cycling of B-vitamins in coastal ecosystems is poorly understood as planktonic uptake rates of vitamins B(1) and B(12) have never been quantified in tandem in any aquatic ecosystem. The goal of this study was to establish the relationships between plankton community composition, carbon fixation, and B-vitamin assimilation in two contrasting estuarine systems. We show that, although B-vitamin concentrations were low (pM), vitamin concentrations and uptake rates were higher within a more eutrophic estuary and that vitamin B(12) uptake rates were significantly correlated with rates of primary production. Eutrophic sites hosted larger bacterial and picoplankton abundances with larger carbon normalized vitamin uptake rates. Although the >2??m phytoplankton biomass was often dominated by groups with a high incidence of vitamin auxotrophy (dinoflagellates and diatoms), picoplankton (<2??m) were always responsible for the majority of B(12)-vitamin uptake. Multiple lines of evidence suggest that heterotrophic bacteria were the primary users of vitamins among the picoplankton during this study. Nutrient/vitamin amendment experiments demonstrated that, in the Summer and Fall, vitamin B(12) occasionally limited or co-limited the accumulation of phytoplankton biomass together with nitrogen. Combined with prior studies, these findings suggest that picoplankton are the primary producers and users of B-vitamins in some coastal ecosystems and that rapid uptake of B-vitamins by heterotrophic bacteria may sometimes deprive larger phytoplankton of these micronutrients and thus influence phytoplankton species succession. PMID:23091470

Koch, Florian; Hattenrath-Lehmann, Theresa K; Goleski, Jennifer A; Sañudo-Wilhelmy, Sergio; Fisher, Nicholas S; Gobler, Christopher J

2012-01-01

2

Vitamin B12  

MedlinePLUS

... other B vitamins, such as niacin, riboflavin, vitamin B6, and magnesium. A prescription form of vitamin B12 ... Board. Dietary Reference Intakes: Thiamin, riboflavin, niacin, vitamin B6, folate, vitamin B12, pantothenic acid, biotin, and choline . ...

3

4-Ethylphenyl-Cobalamin Impairs Tissue Uptake of Vitamin B12 and Causes Vitamin B12 Deficiency in Mice  

PubMed Central

Co?-4-ethylphenyl-cob(III) alamin (EtPhCbl) is an organometallic analogue of vitamin B12 (CNCbl) which binds to transcobalamin (TC), a plasma protein that facilitates the cellular uptake of cobalamin (Cbl). In vitro assays with key enzymes do not convert EtPhCbl to the active coenzyme forms of Cbl suggesting that administration of EtPhCbl may cause cellular Cbl deficiency. Here, we investigate the in vivo effect of EtPhCbl in mice and its ability, if any, to induce Cbl deficiency. We show that EtPhCbl binds to mouse TC and we examined mice that received 3.5 nmol/24h EtPhCbl (n=6), 3.5 nmol/24h CNCbl (n=7) or NaCl (control group) (n=5) through osmotic mini-pumps for four weeks. We analyzed plasma, urine, liver, spleen, submaxillary glands and spinal cord for Cbl and markers of Cbl deficiency including methylmalonic acid (MMA) and homocysteine (tHcy). Plasma MMA (mean±SEM) was elevated in animals treated with EtPhCbl (1.01±0.12 µmol/L) compared to controls (0.30±0.02 µmol/L) and CNCbl (0.29±0.01 µmol/L) treated animals. The same pattern was observed for tHcy. Plasma total Cbl concentration was higher in animals treated with EtPhCbl (128.82±1.87 nmol/L) than in CNCbl treated animals (87.64±0.93 nmol/L). However, the organ levels of total Cbl were significantly lower in animals treated with EtPhCbl compared to CNCbl treated animals or controls, notably in the liver (157.07±8.56 pmol/g vs. 603.85±20.02 pmol/g, and 443.09±12.32 pmol/g, respectively). Differences between the three groups was analysed using one-way ANOVA and, Bonferroni post-hoc test. EtPhCbl was present in all tissues, except the spinal cord, accounting for 35-90% of total Cbl. In conclusion, treatment with EtPhCbl induces biochemical evidence of Cbl deficiency. This may in part be caused by a compromised tissue accumulation of Cbl. PMID:24073261

Mutti, Elena; Ruetz, Markus; Birn, Henrik; Krautler, Bernhard; Nexo, Ebba

2013-01-01

4

Vitamin B12  

MedlinePLUS

... Vitamin B12 is also used for memory loss; Alzheimer’s disease; boosting mood, energy, concentration and the immune system; ... daily reduces the extent and severity of eczema. Alzheimer’s disease. Limited research suggests that higher vitamin B12 intake ...

5

Functional vitamin B12 deficiency.  

PubMed

We describe a case of functional vitamin B12 deficiency where the repeated measurement of a serum B12 level within the normal range led to delay in the diagnosis of subacute combined degeneration of the spinal cord, and possibly permanent neurological damage as a result. Failure of intracellular transport of B12 by transcobalamin-2 can lead to functional B12 deficiency but with apparently normal serum levels, and is suggested by raised levels of either serum methylmalonic acid or homocysteine, associated with low levels of transcobalamin-2. Such patients may respond to repeated high-dose injections of B12. PMID:19151237

Turner, Martin R; Talbot, Kevin

2009-02-01

6

Penicillin and Vitamin B12  

NSDL National Science Digital Library

The WebWare Molecules for July are mentioned in the article "The History of Molecular Structure Determination Viewed through the Nobel Prizes", by Jensen, Palenik, and Suh. One of the recipients discussed, Dorothy Crowfoot Hodgkin, won the Nobel Prize in Chemistry in part for determining the structures of penicillin and vitamin B12.

7

The uptake of vitamin B12 by human lymphocytes and the relationships to the cell cycle.  

PubMed

The phase of the cell cycle permitting transcobalamin II (TC II) mediated entry of cobalamin (Cbl) into human lymphocytes was determined under several conditions. (1) Little was taken up by resting peripheral blood lymphocytes (PBL). (2) Uptake was enhanced by stimulation of PBL by culture with a mitogen. (3) This increase in capacity for uptake took place simultaneously during 3 days of culture with the increase in capacity to synthesize DNA. (4) Hydroxyurea inhibited both DNA synthesis and TC II-Cbl uptake. (5) As culture was prolonged and the cells passed beyond the phase of most active division, DNA synthesis and Cbl uptake declined sharply. (6) The increased capacity to take up Cbl after stimulation was determined, at least in part, by increased receptor activity for TC II-Cbl. (7) Internalization of the Cbl was also increased. (8) Simultaneously with the increasing DNA synthesis, the cells increased in the activity of the Cbl-dependent methionine synthetase (MS). (9) MS activity subsequently fell during longer culture. Thus PBL can take in Cbl only during a narrow "window" in the cell cycle. This window is associated with the period of most active DNA synthesis and at a time when one coenzyme of Cbl, MeCbl, is the most active. PMID:6690641

Hall, C A

1984-01-01

8

Comparison between Serum Holotranscobalamin and Total Vitamin B12 as Indicators of Vitamin B12 Status  

PubMed Central

Objectives This study aims to assess the usefulness of serum holotranscobalamin (holoTC), the fraction of vitamin B12 that is available for tissue uptake, compared with total vitamin B12 in patients investigated for vitamin B12 disorders. Methods Serum samples were randomly selected from 76 patients (48 females, 28 males; age range 12-69 years) referred to the Clinical Biochemistry Laboratory, Royal Hospital for the assessment of vitamin B12 status. For each patient, serum total vitamin B12 level was determined by chemiluminescent microparticle immunoassay on Architect 2000 analyzer and holoTC (active vitamin B12) level was determined by microparticle enzyme immunoassay on Axsym analyzer (both from Abbott, USA). Results Comparison of the data was conducted to reflect the mean, standard deviation (SD) and correlation coefficient between the two groups. The mean (SD) for serum holoTC and total vitamin B12 were 46.5(32.2) pmol/L and 316.3(165.6) pmol/L respectively. There was a significant correlation between holoTC and total vitamin B12 (r= 0.765, P< 0.001) and the regression equation was expressed as; y = a + bx (i.e: holoTC = 1.5 + 0.14 total vitamin B12). Also, the results were assessed for any misclassification when comparing holoTC and the total vitamin B12 in terms of whether each or both values agree or disagree for classifying the patients as having normal or abnormal (low or high) results, based on the cut-off thresholds of the kit’s quoted reference range for holo TC of 9 - 123 pmol/L and for total vitamin B12 of 140-600 pmol/L. Accordingly, in 69 (90.8%) samples, there was a parallel agreement/ classification of results, both being normal or abnormal. In 61 (80.4%) patients, both results were normal, whereas in 4 (5.2%) patients, both results were high, and in 4 (5.2%) patients both results were low. However, in 7 (9.8%) cases, there was disagreement/ misclassification of results; 6 (7.8%) patients, holoTC was normal while total vitamin B12 was low, and in 1 (1.4%) patient, holoTC was normal while total vitamin B12 was high. Conclusion It can be recommended that holoTC and total vitamin B12, alone and in combination, have almost equal diagnostic efficiency in screening/diagnosing vitamin B12 deficiency for the majority of patients. In very few patients, holoTC appeared to be a better reflector of vitamin B12 status. Further comparison studies based on a gold standard method for classifying vitamin B12 status are worth considering. PMID:22125690

Al Aisari, Faiza; Al-Hashmi, Huda; Mula-Abed, Waad-Allah

2010-01-01

9

Good Sources of Nutrients: Vitamin B-12  

E-print Network

material gen?tico en ? todas c?lulas La vitamina B12 para su salud Puede ayudar a prevenir la anemia? ?D?nde se encuentra la vitamina B12? La vitamina B12 ocurre naturalmente en alimentos de fuente animal, tal como el pescado, la carne y el queso... prevent anemia? Where is vitamin B12 found? Vitamin B12 is found naturally in foods that come from animals, such as fish, meat and milk. Fortified foods are an important source of vitamin B12 for veg- etarians. Here are some examples of vitamin B-12...

Scott, Amanda; Replogle, Jacqueline

2008-08-28

10

THE DIAGNOSIS OF VITAMIN B12 DEFICIENCY IN SHEEP: COMPARISON OF SERUM VITAMIN B12 LEVELS  

E-print Network

THE DIAGNOSIS OF VITAMIN B12 DEFICIENCY IN SHEEP: COMPARISON OF SERUM VITAMIN B12 LEVELS MEASURED Nutritionnelles, INRA, CRZV de Theix, 63122 Ceyrat, France Résumé DIAGNOSTIC DE LA CARENCE EN VITAMINE B12 CHEZ LE MOUTON: COMPARAISON DES TAUX DE VITAMINE B12 S�RIQUE MESUR�S PAR DES TECHNIQUES MICROBIOLOGIQUES ET DE

Paris-Sud XI, Université de

11

Vitamin B12 and Cognitive Function  

PubMed Central

Background More than 2.9 million serum vitamin B12 tests were performed in 2010 in Ontario at a cost of $40 million. Vitamin B12 deficiency has been associated with a few neurocognitive disorders. Objective To determine the clinical utility of B12 testing in patients with suspected dementia or cognitive decline. Methods Three questions were addressed: Is there an association between vitamin B12 deficiency and the onset of dementia or cognitive decline? Does treatment with vitamin B12 supplementation improve cognitive function in patients with dementia or cognitive decline and vitamin B12 deficiency? What is the effectiveness of oral versus parenteral vitamin B12 supplementation in those with confirmed vitamin B12 deficiency? A literature search was performed using MEDLINE, Embase, EBSCO Cumulative Index to Nursing & Allied Health Literature (CINAHL), the Cochrane Library, and the Centre for Reviews and Dissemination database, from January 2002 until August 2012. Results Eighteen studies (7 systematic reviews and 11 observational studies) were identified to address the question of the association between B12 and the onset of dementia. Four systematic reviews were identified to address the question of the treatment of B12 on cognitive function. Finally, 3 randomized controlled trials were identified that compared oral B12 to intramuscular B12. Conclusions Based on very low quality evidence, there does appear to be an association between elevated plasma homocysteine levels (a by-product of B vitamins) and the onset of dementia. Based on moderate quality evidence, but with less than optimal duration of follow-up, treatment with B12 supplementation does not appreciably change cognitive function. Based on low to moderate quality of evidence, treatment with vitamin B12 and folate in patients with mild cognitive impairment seems to slow the rate of brain atrophy. Based on moderate quality evidence, oral vitamin B12 is as effective as parenteral vitamin B12 in patients with confirmed B12 deficiency. Plain Language Summary Low levels of vitamin B12 have been associated with neurocognitive disorders. This evidence-based analysis assessed the usefulness of serum vitamin B12 testing as it relates to brain function. This review found very low quality evidence that suggests a connection between high plasma homocysteine levels (a by-product of B vitamin metabolism in the body) and the onset of dementia. Moderate quality of evidence indicates treatment with vitamin B12 does not improve brain function. Moderate quality of evidence also indicates treatment using oral vitamin B12 supplements is as effective as injections of vitamin B12. PMID:24379897

2013-01-01

12

Update on vitamin B12 deficiency.  

PubMed

Vitamin B(12) (cobalamin) deficiency is a common cause of megaloblastic anemia, a variety of neuropsychiatric symptoms, and elevated serum homocysteine levels, especially in older persons. There are a number of risk factors for vitamin B(12) deficiency, including prolonged use of metformin and proton pump inhibitors. No major medical organizations, including the U.S. Preventive Services Task Force, have published guidelines on screening asymptomatic or low-risk adults for vitamin B(12) deficiency, but high-risk patients, such as those with malabsorptive disorders, may warrant screening. The initial laboratory assessment of a patient with suspected vitamin B(12) deficiency should include a complete blood count and a serum vitamin B(12) level. Measurements of serum vitamin B(12) may not reliably detect deficiency, and measurement of serum homocysteine and/or methylmalonic acid should be used to confirm deficiency in asymptomatic high-risk patients with low normal levels of vitamin B(12). Oral administration of high-dose vitamin B(12) (1 to 2 mg daily) is as effective as intramuscular administration in correcting the deficiency, regardless of etiology. Because crystalline formulations are better absorbed than naturally occurring vitamin B(12), patients older than 50 years and strict vegetarians should consume foods fortified with vitamin B(12) and vitamin B(12) supplements, rather than attempting to get vitamin B(12) strictly from dietary sources. Administration of vitamin B(12) to patients with elevated serum homocysteine levels has not been shown to reduce cardiovascular outcomes in high-risk patients or alter the cognitive decline of patients with mild to moderate Alzheimer disease. PMID:21671542

Langan, Robert C; Zawistoski, Kimberly J

2011-06-15

13

Serum vitamin B12 not reflecting vitamin B12 status in patients with type 2 diabetes.  

PubMed

Contradictory results for concentrations of vitamin B12, holotranscobalamin (holoTC), and methylmalonic acid (MMA) have been reported. We tested the hypothesis that the extracellular vitamin B12 markers are not reflecting the intracellular vitamin B12-dependent biochemical reactions in individuals with type 2 diabetes. The study included 92 patients with diabetes and 72 controls with similar age and sex distribution. We measured vitamin B12 markers [MMA, total serum vitamin B12, holoTC, total homocysteine (tHcy)], red blood cell (RBC)-B12, and the plasma concentrations of the methylation markers [S-adenosylmethionine (SAM) and S-adenosylhomocysteine (SAH)]. In comparison to controls, diabetic patients showed significantly higher concentrations of plasma SAH (median 15.1 vs. 11.8 nmol/L; p < 0.001) and lower SAM/SAH ratio (9.1 vs. 8.2; p = 0.006). Concentrations of total vitamin B12 and holoTC did not differ significantly between the groups, but plasma MMA concentrations were significantly higher in diabetics (250 vs. 206 nmol/L). However, RBC-B12 was lower in diabetics compared to controls (median 230 vs. 260 pmol/L; p = 0.001). The inverse correlation between MMA and RBC-B12 was stronger in the controls compared to that in the patients (correlation coefficient in controls R = -0.446, p = 0.001; in patients R = -0.289, p = 0.022). Metformin treatment was associated with a lower total serum vitamin B12, but a comparable RBC-B12 and a slightly lower MMA and better methylation index. In conclusion, patients with type 2 diabetes showed normal extracellular vitamin B12, but disturbed intracellular B12-dependent biochemical reactions. Metformin treatment was associated with low serum vitamin B12 and improved intracellular vitamin B12 metabolism despite low serum vitamin B12. PMID:23168250

Obeid, Rima; Jung, John; Falk, Julia; Herrmann, Wolfgang; Geisel, Jürgen; Friesenhahn-Ochs, Bettina; Lammert, Frank; Fassbender, Klaus; Kostopoulos, Panagiotis

2013-05-01

14

Assay for vitamin B12 absorption and method of making labeled vitamin B12  

DOEpatents

The invention provides methods for labeling vitamin B12 with .sup.14C, .sup.13C, tritium, and deuterium. When radioisotopes are used, the invention provides for methods of labeling B12 with high specific activity. The invention also provides labeled vitamin B12 compositions made in accordance with the invention.

Anderson, Peter J. (Davis, CA); Dueker, Stephen (Davis, CA); Miller, Joshua (Davis, CA); Green, Ralph (Elmacero, CA); Roth, John (Davis, CA); Carkeet, Colleen (Silver Spring, MD); Buchholz,; Bruce A. (Orinda, CA)

2012-06-19

15

Human vitamin B12 absorption measurement by accelerator mass spectrometry using specifically  

E-print Network

Human vitamin B12 absorption measurement by accelerator mass spectrometry using specifically to assimilate dietary vitamin B12. Assaying and understanding absorption and uptake of B12 is important because and showed plasma appearance and clearance curves consistent with the predicted behavior of the pure vitamin

California at Davis, University of

16

Molecular Structure of Vitamin B12  

NSDL National Science Digital Library

Vitamin B12 (cyanocobalamin) has many uses as a nutritional supplement in both humans and livestock. It is used in humans to treat pernicious anemia, hepatitis, cirrhosis of the liver, and to help maintain the body's metabolism. In its long-effect form (hydroxocobalamin), vitamin B12 is used to treat anemia, growth impediment, improvement in the function of the heart, liver, kidneys and nerves, and general strengthening of the body. In livestock, it is used to improve feed production.

2002-08-13

17

Metformin-related vitamin B12 deficiency.  

PubMed

Metformin is an invaluable hypoglycaemic agent. We report two cases who had symptomatic vitamin B12 deficiency related to metformin use; the mechanisms are discussed. The clinician must be aware of the possibility of metformin-associated B12 deficiency in users who suffer cognitive impairment, peripheral neuropathy, subacute combined degeneration of the cord or anaemia. PMID:16495296

Liu, Kin Wah; Dai, Lok Kwan; Jean, Woo

2006-03-01

18

The discovery of vitamin B(12).  

PubMed

The discovery of vitamin B(12), the elucidation of its role in metabolism, and the effects and treatment of its deficiency occurred in distinct phases over more than 100 years, and it was the subject of two separate Nobel Prizes. The valuable contribution of clinical reports and studies of patients with pernicious anemia throughout the 19th century resulted in enough clinical definition to allow Minot and Murphy to put together the first hallmark study on treatment of the condition, leading them to a Nobel Prize. These researchers were not the first to suggest that an inadequacy of nutrients was the cause of pernicious anemia, but their particular input was a carefully designed intervention in well-characterized pernicious anemia patients, of a special diet containing large amounts of liver. They found consistent improvement in the clinical and blood status of all subjects, most of whom remained on remission indefinitely. After the successful intervention studies, the next advance was made by Castle who discovered that a gastric component, which he called intrinsic factor, was missing in pernicious anemia. Many years later, intrinsic factor was found to be a glycoprotein that formed a complex with vitamin B(12), promoting its absorption through ileal receptors. The vitamin was isolated by two groups simultaneously and was crystallized and characterized in the laboratory of Dorothy Hodgkin, contributing to her Nobel Prize in 1964. Subsequently, the various biochemical roles of vitamin B(12) were elucidated, including its important interaction with folate and their common link with megaloblastic anemia. Many of the early clinical studies recognized that vitamin B(12) deficiency also caused a severe neuropathy leading to paralysis and death, while post mortem analysis demonstrated spinal cord demyelination. Vitamin B(12) is still the subject of intense research and, in particular, its role in preventing these irreversible neurological lesions remains unclear. PMID:23183296

Scott, John M; Molloy, Anne M

2012-01-01

19

21 CFR 184.1945 - Vitamin B12.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Vitamin B12. 184.1945 Section 184.1945 Food and Drugs FOOD AND DRUG ADMINISTRATION...Listing of Specific Substances Affirmed as GRAS § 184.1945 Vitamin B12. (a) Vitamin B12 , also...

2011-04-01

20

21 CFR 184.1945 - Vitamin B12.  

...2014-04-01 2014-04-01 false Vitamin B12. 184.1945 Section 184.1945 Food and Drugs FOOD AND DRUG ADMINISTRATION...Listing of Specific Substances Affirmed as GRAS § 184.1945 Vitamin B12. (a) Vitamin B12 , also...

2014-04-01

21

21 CFR 184.1945 - Vitamin B12.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Vitamin B12. 184.1945 Section 184.1945 Food and Drugs FOOD AND DRUG ADMINISTRATION...Listing of Specific Substances Affirmed as GRAS § 184.1945 Vitamin B12. (a) Vitamin B12 , also...

2012-04-01

22

21 CFR 184.1945 - Vitamin B12.  

Code of Federal Regulations, 2010 CFR

...Drugs 3 2010-04-01 2009-04-01 true Vitamin B12. 184.1945 Section 184.1945 Food and...Specific Substances Affirmed as GRAS § 184.1945 Vitamin B12. (a) Vitamin B12 , also known as cyanocobalamin (C63...

2010-04-01

23

21 CFR 862.1810 - Vitamin B12 test system.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Vitamin B12 test system. 862.1810 Section...Chemistry Test Systems § 862.1810 Vitamin B12 test system. (a) Identification. A vitamin B12 test system is a device intended...

2012-04-01

24

21 CFR 184.1945 - Vitamin B 12..  

Code of Federal Regulations, 2013 CFR

... 3 2013-04-01 2013-04-01 false Vitamin B 12.. 184.1945 Section 184.1945 Food...Specific Substances Affirmed as GRAS § 184.1945 Vitamin B 12 .. (a) Vitamin B12 , also known as cyanocobalamin (C63...

2013-04-01

25

Radiolysis of cyanocobalamin (vitamin B 12)  

NASA Astrophysics Data System (ADS)

Research on the radiolysis of vitamins is of considerable interest since these compounds are important nutritional constituents in foods and in dietetic supplements. In spite of these considerations there are few data and very often difficult to compare for the radiolytic behavior of vitamins. In this work we focused our attention on to the study of the radiolysis of cyanocobalamin (vitamin B 12) in solid state and in aqueous solutions. The procedure was followed by HPLC and UV-spectroscopy. The results obtained in aqueous solutions showed a dependence of the decomposition as a linear function of the dose. The G of decomposition for a 1×10 -5 M solution was 3.3. In the solid state the vitamin was very stable towards the irradiation in the conditions used in this study with a G=2.1×10 -3. A study made with Serratia marcescens as a microbiological contaminant showed that at the sterilization dose there is a destruction of the vitamin in aqueous solution. In the solid state the degree of decomposition was 7%.

Juanchi, X.; Albarran, G.; Negron-Mendoza, A.

2000-03-01

26

Factors affecting formiminoglutamic acid excretion in vitamin B12 deficiency  

PubMed Central

1. Formiminoglutamic acid, a product of the catabolism of histidine, is excreted in abnormally large amounts in the urines of vitamin B12-deficient rats and of vitamin B12-deficient sheep; the excretion is reduced to negligible amounts after administration of vitamin B12. 2. After administration of certain methyl donors to vitamin B12-deficient rats or sheep urinary excretion of formiminoglutamic acid is temporarily decreased. 3. Irrespective of the pteroylglutamic acid status of the animals neither vitamin B12-deficient rats nor vitamin B12-deficient sheep have the ability to deal efficiently with histidine. 4. In sheep, urinary excretion of formiminoglutamic acid is increased after administration of aminopterin; treatment with pteroylglutamic acid restores the ability of the animal to deal with the catabolic products of histidine. 5. The possible functions of vitamin B12 and methionine in relieving a virtual deficiency of pteroylglutamic acid are discussed. PMID:5435494

Marston, Hedley R.; Allen, Shirley H.

1970-01-01

27

CARDIOVASCULAR LESIONS IN COBALT-VITAMIN B12 DEFICIENT SHEEP  

E-print Network

CARDIOVASCULAR LESIONS IN COBALT-VITAMIN B12 DEFICIENT SHEEP R. MOHAMMED M. LAMAND Laboratoire des LE MOUTON CARENCÃ? EN COBALT-VITAMINE B12. ― Des lésions cardiovasculaires ont été observées à l'autopsie chez 5 des 6 moutons soumis à une carence expérimentale en cobalt-vitamine B12 pendant 34

Paris-Sud XI, Université de

28

Vegan Diet, Subnormal Vitamin B-12 Status and Cardiovascular Health  

PubMed Central

Vegetarian diets have been associated with atherosclerosis protection, with healthier atherosclerosis risk profiles, as well as lower prevalence of, and mortality from, ischemic heart disease and stroke. However, there are few data concerning the possible cardiovascular effects of a vegan diet (with no meat, dairy or egg products). Vitamin B-12 deficiency is highly prevalent in vegetarians; this can be partially alleviated by taking dairy/egg products in lact-ovo-vegetarians. However, metabolic vitamin B-12 deficiency is highly prevalent in vegetarians in Australia, Germany, Italy and Austria, and in vegans (80%) in Hong Kong and India, where vegans rarely take vitamin B-12 fortified food or vitamin B-12 supplements. Similar deficiencies exist in northern Chinese rural communities consuming inadequate meat, egg or dairy products due to poverty or dietary habits. Vascular studies have demonstrated impaired arterial endothelial function and increased carotid intima-media thickness as atherosclerosis surrogates in such metabolic vitamin B-12 deficient populations, but not in lactovegetarians in China. Vitamin B-12 supplementation has a favourable impact on these vascular surrogates in Hong Kong vegans and in underprivileged communities in northern rural China. Regular monitoring of vitamin B-12 status is thus potentially beneficial for early detection and treatment of metabolic vitamin B-12 deficiency in vegans, and possibly for prevention of atherosclerosis-related diseases.

Woo, Kam S.; Kwok, Timothy C.Y.; Celermajer, David S.

2014-01-01

29

Vitamin B12 content in raw and cooked beef.  

PubMed

The aim of this work was to evaluate the vitamin B12 content and profile of cobalamin bioactive forms in raw and cooked beef. The study showed that vitamin B12 distribution is unequal among beef muscles. The content of this nutrient ranges from 0.7 to 1.5 ?g/100 g of tissue. In beef, three biologically active forms of vitamin B12 were determined, i.e.: methylcobalamin, adenosylcobalamin and hydroxycobalamin; the dominating form of vitamin B12 was adenosylcobalamin (68% of total cobalamins). The process of roasting and grilling had little effect on the vitamin B12 content in the final product as compared to the raw meat. The fried product was characterised by about a 32% lower content of cobalamins than in raw meat. PMID:24361556

Czerwonka, Ma?gorzata; Szterk, Arkadiusz; Waszkiewicz-Robak, Bo?ena

2014-03-01

30

[Vitamin B12 deficiency: a challenging diagnosis and treatment].  

PubMed

Vitamin B12 deficiency is usually evoked in presence of compatible hematologic or clinical (usually neurologic) signs. However, many cases of deficiency are little or not symptomatic. Pernicious anemia, caused by a deficiency in intrinsic factor, is a rare cause of vitamin B12 deficiency. The most frequent causes are gastric disorders, pancreatic insufficiency, or chronic drug treatment (proton pump inhibitors or metformin) that interfere with the digestion of vitamin B12 digestion, or disorders of the ileum mucosa reducing the absorption of vitamin B12. Oral treatment of vitamin B12 deficiency is possible whatever the etiology, but it has only been validated in small series. Parenteral treatment remains indicated for severe neurologic deficits or whenever patient adherence with treatment is doubtful. PMID:19024576

Rufenacht, Pierre; Mach-Pascual, Sara; Iten, Anne

2008-10-15

31

Transcobalamin 776C3G polymorphism negatively affects vitamin B12 metabolism1-3  

Microsoft Academic Search

Background: A common genetic polymorphism (transcobalamin (TC) 776C3G) may affect the function of transcobalamin, the pro- tein required for vitamin B-12 cellular uptake and metabolism. Re- methylation of homocysteine is dependent on the production of 5-methyltetrahydrofolate and adequate vitamin B-12 for the methi- onine synthase reaction. Objectives: The objectives were to assess the influence of the TC 776C3 G polymorphism

Kristina M von Castel-Dunwoody; Karla P Shelnutt; Jaimie D Vaughn; Elizabeth R Griffin; David R Maneval; Douglas W Theriaque; Lynn B Bailey

32

Genome-wide Association Study of Vitamin B6, Vitamin B12, Folate,  

E-print Network

REPORT Genome-wide Association Study of Vitamin B6, Vitamin B12, Folate, and Homocysteine Blood Schlessinger,12 Manuela Uda,6 and Luigi Ferrucci2 The B vitamins are components of one-carbon metabolism (OCM circulating vitamin B6, vitamin B12, folate and homocysteine, a genome-wide association analysis was conducted

Abecasis, Goncalo

33

Enhancement of chemiluminescence for vitamin B12 analysis.  

PubMed

In the current article, chemiluminescence (CL) from the vitamin B(12) and luminol reaction was studied under alkaline conditions to develop a sensitive analytical method for vitamin B(12) using the carbonate enhancement effect. The method was successfully applied to the determination of vitamin B(12) in vitamin B(12) tablets, multivitamin capsules, and vitamin B(12) injections. Experimental parameters were optimized, including luminol concentration, urea-hydrogen peroxide (urea-H(2)O(2)) concentration, effect of pH, and sequence of addition of reactants for obtaining maximum CL, which was not explored previously. The limit of detection was 5 pg/ml, and the linear range was 10 pg/ml to 1 microg/ml with a regression coefficient of R(2)=0.9998. The importance of these experimental parameters and the carbonate enhancement effect is discussed based on the knowledge of the mechanism of oxidation of luminol and decomposition of urea-H2O2 in the presence of vitamin B(12). Extraction of vitamin B(12) was carried out, and the observed recovery was 97-99.2% with a relative standard deviation in the range of 0.30-1.09%. The results obtained were compared with those of the flame atomic absorption spectrometry method. PMID:19250918

Kumar, Sagaya Selva; Chouhan, Raghuraj Singh; Thakur, Munna Singh

2009-05-15

34

Use of Cheese Whey for Vitamin B12 Production  

PubMed Central

The suitability of cheese whey as a substrate for vitamin B12 production by Propionibacterium shermanii was studied. It was found that with a given level of whey solids a definite amount of yeast extract was required to give maximal yields of vitamin B12. Of the levels of materials studied, 10% whey solids and 1.5% yeast extract gave the best yields of vitamin B12. Most of the lactose of the whey had been utilized in all flask cultures after 168 hr at 29 C. Images Fig. 1 PMID:5970817

Bullerman, L. B.; Berry, E. C.

1966-01-01

35

Vitamin B12 absorption in patients with ileal conduits.  

PubMed

The absorption of vitamin B12 was assessed using the 58Co-absorption test (Schilling test) in 39 patients in whom ileal loops had been used as urinary diversion after excision of the bladder for transitional cell carcinoma. 29% of the patients were found to absorb less than 12% of the offered dose of labelled vitamin B12 after excluding gastric-mediated malabsorption by the modified Schilling test. Examination of haemoglobin, MCV or vitamin B12 in the peripheral blood gave unreliable indications of the absorptive ability of these patients. PMID:1233167

Rogers, A C; Steyn, J H

1975-01-01

36

21 CFR 862.1810 - Vitamin B12 test system.  

Code of Federal Regulations, 2010 CFR

...to measure vitamin B12 in serum, plasma, and urine. Measurements obtained by this device are used in the diagnosis and treatment of anemias of gastrointestinal malabsorption. (b) Classification. Class...

2010-04-01

37

21 CFR 862.1810 - Vitamin B 12 test system.  

Code of Federal Regulations, 2013 CFR

...ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems § 862.1810 Vitamin B 12 test system. (a) Identification....

2013-04-01

38

21 CFR 862.1810 - Vitamin B 12 test system.  

...ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems § 862.1810 Vitamin B 12 test system. (a) Identification....

2014-04-01

39

Neuroenhancement with Vitamin B12—Underestimated Neurological Significance  

PubMed Central

Vitamin B12 is a cofactor of methionine synthase in the synthesis of methionine, the precursor of the universal methyl donor S-Adenosylmethionine (SAMe), which is involved in different epigenomic regulatory mechanisms and especially in brain development. A Vitamin B12 deficiency expresses itself by a wide variety of neurological manifestations such as paraesthesias, skin numbness, coordination disorders and reduced nerve conduction velocity. In elderly people, a latent Vitamin B12 deficiency can be associated with a progressive brain atrophy. Moderately elevated concentrations of homocysteine (>10 µmol/L) have been associated with an increased risk of dementia, notably Alzheimer’s disease, in many cross-sectional and prospective studies. Raised plasma concentrations of homocysteine is also associated with both regional and whole brain atrophy, not only in Alzheimer’s disease but also in healthy elderly people. Clinician awareness should be raised to accurately diagnose and treat early Vitamin B12 deficiency to prevent irreversible structural brain damage. PMID:24352086

Gröber, Uwe; Kisters, Klaus; Schmidt, Joachim

2013-01-01

40

Neuroenhancement with vitamin B12-underestimated neurological significance.  

PubMed

Vitamin B12 is a cofactor of methionine synthase in the synthesis of methionine, the precursor of the universal methyl donor S-Adenosylmethionine (SAMe), which is involved in different epigenomic regulatory mechanisms and especially in brain development. A Vitamin B12 deficiency expresses itself by a wide variety of neurological manifestations such as paraesthesias, skin numbness, coordination disorders and reduced nerve conduction velocity. In elderly people, a latent Vitamin B12 deficiency can be associated with a progressive brain atrophy. Moderately elevated concentrations of homocysteine (>10 µmol/L) have been associated with an increased risk of dementia, notably Alzheimer's disease, in many cross-sectional and prospective studies. Raised plasma concentrations of homocysteine is also associated with both regional and whole brain atrophy, not only in Alzheimer's disease but also in healthy elderly people. Clinician awareness should be raised to accurately diagnose and treat early Vitamin B12 deficiency to prevent irreversible structural brain damage. PMID:24352086

Gröber, Uwe; Kisters, Klaus; Schmidt, Joachim

2013-12-01

41

A Rare Case of Vitamin B12 Deficiency with Ascites  

PubMed Central

Vitamin B12 deficiency is widespread than assumed in population. At risk are older people, pregnant women, vegans, patients with renal and intestinal diseases. Vitamin B12 deficiency can present with various hematological, gastrointestinal and neurological manifestations. In the population, the prevalence of vitamin B12 deficiency in younger people is 5% to 7% which is less compared to elderly people. In developing countries, deficiency is much more common, starting in early life and persisting across the life span. Here, we present a 16-year-old female patient presenting with ascites since 2 months who was subsequently investigated and diagnosed to have nutritional megaloblastic anaemia secondary to vitamin B12 deficiency after exclusion of other infective, neoplastic, autoimmune and inflammatory diseases. Inspite, patient was treated with antitubercular drugs but she did not respond. After supplementation of Vitamin B12, ascites responded well. Inadequate intake due to low consumption of animal source foods is the main cause of low serum vitamin B12 in younger adults and likely the main cause in poor population worldwide.

Reddy, Mugannagari Maheshwar; Vaddera, Sameeraja; Rajini, G; Tikeli, Vinil

2014-01-01

42

Utility of measuring vitamin B12 and its active fraction, holotranscobalamin, in neurological vitamin B12 deficiency syndromes.  

PubMed

Vitamin B(12) (VitB(12), cobalamin) deficiency has been associated with various neuropsychiatric conditions, such as peripheral neuropathy, subacute combined degeneration, affective disorders, and cognitive impairment. Current assays analyze vitamin B(12), of which only a small percentage is metabolically active. Measurement of its active fraction, holotranscobalamin, might be of greater relevance, but data in populations with neuropsychiatric populations are lacking. In this study, in order to validate VitB(12) and holotranscobalamin (holoTC) serum levels for the detection of VitB(12) deficiency in neuropsychiatric conditions, we compared the validity of VitB(12) and holoTC in a patient cohort with neuropsychiatric conditions suspicious for VitB(12) deficiency. The cohort included all patients admitted to the Department of Neurology at our university between 2005 and 2009 with at least two parameters of the VitB(12) metabolism available (n = 1,279). We used elevated methylmalonic acid as the external validation criterion for VitB(12) deficiency and restricted our analyses to subjects with normal renal function. Among all normal renal function patients, 13.2% had VitB(12) deficiency. In receiver operating characteristic curve (ROC) analysis, correlation of VitB(12) and holoTC with vitamin B(12) deficiency was generally weak, and the areas under the curve (AUC) were not significantly different for holoTC compared to vitamin B(12) in all subjects (AUC: 0.66 [95%CI: 0.51-0.82]; p = 0.04 vs. 0.72 [0.65-0.78], p < 0.0001) and in subcohorts of patients with classical VitB(12) deficiency syndromes. The positive predictive values for holoTC and vitamin B(12) were low (14.7 vs. 21.0%) and both were associated with more false-positive than true-positive test results. holoTC does not show superior diagnostic accuracy compared to VitB(12) for the detection of VitB(12) deficiency in subjects with neuropsychiatric conditions. Neither test can be recommended to diagnose VitB(12) deficiency in subjects with neuropsychiatric disorders. PMID:20890610

Schrempf, Wiebke; Eulitz, Marco; Neumeister, Volker; Siegert, Gabriele; Koch, Rainer; Reichmann, Heinz; Storch, Alexander

2011-03-01

43

Thermotoga lettingae Can Salvage Cobinamide To Synthesize Vitamin B12  

PubMed Central

We recently reported that the Thermotogales acquired the ability to synthesize vitamin B12 by acquisition of genes from two distantly related lineages, Archaea and Firmicutes (K. S. Swithers et al., Genome Biol. Evol. 4:730–739, 2012). Ancestral state reconstruction suggested that the cobinamide salvage gene cluster was present in the Thermotogales' most recent common ancestor. We also predicted that Thermotoga lettingae could not synthesize B12 de novo but could use the cobinamide salvage pathway to synthesize B12. In this study, these hypotheses were tested, and we found that Tt. lettingae did not synthesize B12 de novo but salvaged cobinamide. The growth rate of Tt. lettingae increased with the addition of B12 or cobinamide to its medium. It synthesized B12 when the medium was supplemented with cobinamide, and no B12 was detected in cells grown on cobinamide-deficient medium. Upstream of the cobinamide salvage genes is a putative B12 riboswitch. In other organisms, B12 riboswitches allow for higher transcriptional activity in the absence of B12. When Tt. lettingae was grown with no B12, the salvage genes were upregulated compared to cells grown with B12 or cobinamide. Another gene cluster with a putative B12 riboswitch upstream is the btuFCD ABC transporter, and it showed a transcription pattern similar to that of the cobinamide salvage genes. The BtuF proteins from species that can and cannot salvage cobinamides were shown in vitro to bind both B12 and cobinamide. These results suggest that Thermotogales species can use the BtuFCD transporter to import both B12 and cobinamide, even if they cannot salvage cobinamide. PMID:24014541

Butzin, Nicholas C.; Secinaro, Michael A.; Swithers, Kristen S.; Gogarten, J. Peter

2013-01-01

44

Involuntary movements due to vitamin B12 deficiency.  

PubMed

Deficiency of vitamin B12 produces protean effects on the nervous system, most commonly neuropathy, myelopathy, cognitive and behavioural symptoms, and optic atrophy. Involuntary movements comprise a relatively rare manifestation of this readily treatable disorder. Both adults and infants deficient in vitamin B12 may present with chorea, tremor, myoclonus, Parkinsonism, dystonia, or a combination of these, which may precede diagnosis or become apparent only a few days after parenteral replacement therapy has begun. The pathogenesis of these movement disorders shows interesting parallels to certain neurodegenerative conditions. The clinical syndrome responds well to vitamin B12 supplementation in most cases, and an early diagnosis is essential to reverse the haematological and neurological dysfunction characteristic of this disorder. In this article, we elucidate the association of vitamin B12 deficiency with movement disorders in adults and in infants, discuss the pathogenesis of this association, review previously reported cases, and present a young adult male with severe generalized chorea that showed a salutary response to vitamin B12 supplementation. PMID:24852503

Souza, Aaron de; Moloi, M W

2014-12-01

45

Association of Biochemical B12 Deficiency With Metformin Therapy and Vitamin B12 Supplements  

PubMed Central

OBJECTIVE To describe the prevalence of biochemical B12 deficiency in adults with type 2 diabetes taking metformin compared with those not taking metformin and those without diabetes, and explore whether this relationship is modified by vitamin B12 supplements. RESEARCH DESIGN AND METHODS Analysis of data on U.S. adults ?50 years of age with (n = 1,621) or without type 2 diabetes (n = 6,867) from the National Health and Nutrition Examination Survey (NHANES), 1999–2006. Type 2 diabetes was defined as clinical diagnosis after age 30 without initiation of insulin therapy within 1 year. Those with diabetes were classified according to their current metformin use. Biochemical B12 deficiency was defined as serum B12 concentrations ?148 pmol/L and borderline deficiency was defined as >148 to ?221 pmol/L. RESULTS Biochemical B12 deficiency was present in 5.8% of those with diabetes using metformin compared with 2.4% of those not using metformin (P = 0.0026) and 3.3% of those without diabetes (P = 0.0002). Among those with diabetes, metformin use was associated with biochemical B12 deficiency (adjusted odds ratio 2.92; 95% CI 1.26–6.78). Consumption of any supplement containing B12 was not associated with a reduction in the prevalence of biochemical B12 deficiency among those with diabetes, whereas consumption of any supplement containing B12 was associated with a two-thirds reduction among those without diabetes. CONCLUSIONS Metformin therapy is associated with a higher prevalence of biochemical B12 deficiency. The amount of B12 recommended by the Institute of Medicine (IOM) (2.4 ?g/day) and the amount available in general multivitamins (6 ?g) may not be enough to correct this deficiency among those with diabetes. PMID:22179958

Reinstatler, Lael; Qi, Yan Ping; Williamson, Rebecca S.; Garn, Joshua V.; Oakley, Godfrey P.

2012-01-01

46

Breast milk vitamin B-12 concentrations in Guatemalan women are correlated with maternal but not infant vitamin B-12 status at 12 months postpartum.  

PubMed

In our previous studies, one-third of lactating Guatemalan women, infants, and children had deficient or marginal serum vitamin B-12 concentrations. Relationships among maternal and infant status and breast milk vitamin B-12, however, have not, to our knowledge, been investigated in such populations. Our purpose was to measure breast milk vitamin B-12 in Guatemalan women with a range of serum vitamin B-12 concentrations and explore associations between milk vitamin B-12 concentrations and maternal and infant vitamin B-12 intake and status. Participants were 183 mother-infant pairs breastfeeding at 12 mo postpartum. Exclusion criteria included mother <17 y, infant <11.5 or >12.5 mo, multiple birth, reported health problems in mother or infant, and mother pregnant >3 mo. Data collected on mothers and infants included anthropometry, serum and breast milk vitamin B-12, and dietary vitamin B-12. Serum vitamin B-12 concentrations indicated deficiency (<150 pmol/L) in 35% of mothers and 27% of infants and marginal status (150-220 pmol/L) in 35% of mothers and 17% of infants. In a multiple regression analysis, breast milk vitamin B-12 concentration was associated (P < 0.05) with both maternal vitamin B-12 intake (r = 0.26) and maternal serum vitamin B-12 (r = 0.30). Controlling for the number of breastfeeds per day and vitamin B-12 intake from complementary foods, infant serum vitamin B-12 was associated with maternal serum vitamin B-12 (r = 0.31; P < 0.001) but not breast milk vitamin B-12, implicating a long-term effect of pregnancy status on infant vitamin B-12 status at 12 mo postpartum. PMID:22131550

Deegan, Kathleen L; Jones, Katherine M; Zuleta, Clara; Ramirez-Zea, Manuel; Lildballe, Dorte L; Nexo, Ebba; Allen, Lindsay H

2012-01-01

47

Oral contraceptives: effect of folate and vitamin B12 metabolism.  

PubMed Central

Women who use oral contraceptives have impaired folate metabolism as shown by slightly but significantly lower levels of folate in the serum and the erythrocytes and an increased urinary excretion of formiminoglutamic acid. The vitamin B12 level in their serum is also significantly lower than that of control groups. However, there is no evidence of tissue depletion of vitamin B12 associated with the use of oral contraceptives. The causes and clinical significance of the impairment of folate and vitamin B12 metabolism in these women is discussed in this review of the literature. Clinicians are advised to ensure that women who shop taking "the pill" because they wish to conceive have adequate folate stores before becoming pregnant. PMID:7037144

Shojania, A. M.

1982-01-01

48

A vitamin B-12 supplement of 500 ?g/d for eight weeks does not normalize urinary methylmalonic acid or other biomarkers of vitamin B-12 status in elderly people with moderately poor vitamin B-12 status.  

PubMed

Plasma vitamin B-12 is the most commonly used biomarker of vitamin B-12 status, but the predictive value for low vitamin B-12 status is poor. The urinary methylmalonic acid (uMMA) concentration has potential as a functional biomarker of vitamin B-12 status, but the response to supplemental vitamin B-12 is uncertain. A study was conducted to investigate the responsiveness of uMMA to supplemental vitamin B-12 in comparison with other biomarkers of vitamin B-12 status [plasma vitamin B-12, serum holotranscobalamin (holoTC), plasma MMA] in elderly people with moderately poor vitamin B-12 status. A double-blind, placebo-controlled, randomized 8-wk intervention study was carried out using vitamin B-12 supplements (500 ?g/d, 100 ?g/d, and 10 ?g/d cyanocobalamin) in 100 elderly people with a combined plasma vitamin B-12 <250 pmol/L and uMMA ratio (?mol MMA/mmol creatinine) >1.5. All biomarkers had a dose response to supplemental vitamin B-12. Improvements in plasma vitamin B-12 and serum holoTC were achieved at cobalamin supplements of 10 ?g/d, but even 500 ?g/d for 8 wk did not normalize plasma vitamin B-12 in 8% and serum holoTC in 12% of people. The response in uMMA was comparable with plasma MMA; 15-25% of people still showed evidence of metabolic deficiency after 500 ?g/d cobalamin for 8 wk. There was a differential response in urinary and plasma MMA according to smoking behavior; the response was enhanced in ex-smokers compared with never-smokers. uMMA offers an alternative marker of metabolic vitamin-B12 status, obviating the need for blood sampling. PMID:23236022

Hill, Marilyn H; Flatley, Janet E; Barker, Margo E; Garner, Clare M; Manning, Nigel J; Olpin, Simon E; Moat, Stuart J; Russell, Jean; Powers, Hilary J

2013-02-01

49

High-dose compared with low-dose vitamin B-12 supplement use is not associated with higher vitamin B-12 status in children, adolescents, and older adults.  

PubMed

Over-the-counter vitamin supplements on the Canadian market are permitted to contain a daily vitamin B-12 dose of up to 1000 ?g. Our objective was to determine the association between total daily vitamin B-12 supplement dose and markers of vitamin B-12 status in Canadians. Blood collected from a nationally representative sample aged 6-79 y (n = ?5600) in the Canadian Health Measures Survey (2007-2009) was analyzed for serum vitamin B-12 and plasma total homocysteine (tHcy). Total daily intake of vitamin B-12 from single and multivitamin supplements was calculated. Individuals that indicated proton pump inhibitor or vitamin B-12 injection treatment were excluded from the supplement dose and tHcy analyses; folate-deficient individuals were also excluded from the tHcy analysis. Twenty-three percent of children, 12.3% of adolescents, and 25.5% of adults consumed a vitamin B-12-containing supplement. Supplement users had 33% higher serum vitamin B-12 and 4.2% higher prevalence of adequacy than did non-supplement users. Children and adolescents consuming >10 ?g/d supplemental vitamin B-12 did not demonstrate higher serum vitamin B-12, higher prevalence of serum vitamin B-12 adequacy, or lower tHcy than did those consuming >0-10 ?g/d. The association between serum vitamin B-12 reached a plateau at doses of >25 and >10-25 ?g/d in adults aged 46-59 and 60-79 y, respectively. The prevalences of serum vitamin B-12 adequacy and normal tHcy, and tHcy did not differ by vitamin B-12 supplement dose in adults >45 y. In this cross-sectional study, vitamin B-12 supplement doses >10-25 ?g/d were not associated with higher vitamin B-12 status in children, adolescents, or older adults compared with lower doses. PMID:24699807

MacFarlane, Amanda J; Shi, Yipu; Greene-Finestone, Linda S

2014-06-01

50

Involuntary movements misdiagnosed as seizure during vitamin B12 treatment.  

PubMed

Seizures and epilepsy are a common problem in childhood. Nonepileptic paroxysmal events are conditions that can mimic seizure and frequent in early childhood. Nonepileptic paroxysmal events can be due to physiological or exaggerated physiological responses, parasomnias, movement disorders, behavioral or psychiatric disturbances, or to hemodynamic, respiratory, or gastrointestinal dysfunction. Vitamin B12 deficiency is a treatable cause of failure to thrive and developmental regression, involuntary movements, and anemia. Involuntary movements rarely may appear a few days after the initiation of vitamin B12 treatments and might be misdiagnosed as seizure. Here, we report 2 patients who presented with involuntary movements with his video image. PMID:24196096

Carman, Kursat Bora; Belgemen, Tugba; Yis, Uluc

2013-11-01

51

Vitamin B12 deficit and development of geriatric syndromes  

PubMed Central

Vitamin B12 deficiency or cyanocobalamin is a common condition in the elderly. It is repeatedly overlooked due to multiple clinical manifestations that can affect the blood, neurological, gastrointestinal, and cardiovascular systems, skin and mucous membranes. The various presentations of vitamin B12 deficiency are related to the development of geriatric syndromes like frailty, falls, cognitive impairment, and geriatric nutritional syndromes like protein-energy malnutrition and failure to thrive, in addition to enhancing aging anorexia and cachexia. Therefore, interventions must be developed to include their screening and diagnosis to make early and appropriate treatment to prevent its complications before they become irreversible. PMID:24892321

2013-01-01

52

Iron Limitation of a Springtime Bacterial and Phytoplankton Community in the Ross Sea: Implications for Vitamin B12 Nutrition  

PubMed Central

The Ross Sea is home to some of the largest phytoplankton blooms in the Southern Ocean. Primary production in this system has previously been shown to be iron limited in the summer and periodically iron and vitamin B12 colimited. In this study, we examined trace metal limitation of biological activity in the Ross Sea in the austral spring and considered possible implications for vitamin B12 nutrition. Bottle incubation experiments demonstrated that iron limited phytoplankton growth in the austral spring while B12, cobalt, and zinc did not. This is the first demonstration of iron limitation in a Phaeocystis antarctica-dominated, early season Ross Sea phytoplankton community. The lack of B12 limitation in this location is consistent with previous Ross Sea studies in the austral summer, wherein vitamin additions did not stimulate P. antarctica growth and B12 was limiting only when bacterial abundance was low. Bottle incubation experiments and a bacterial regrowth experiment also revealed that iron addition directly enhanced bacterial growth. B12 uptake measurements in natural water samples and in an iron fertilized bottle incubation demonstrated that bacteria serve not only as a source for vitamin B12, but also as a significant sink, and that iron additions enhanced B12 uptake rates in phytoplankton but not bacteria. Additionally, vitamin uptake rates did not become saturated upon the addition of up to 95?pM B12. A rapid B12 uptake rate was observed after 13?min, which then decreased to a slower constant uptake rate over the next 52?h. Results from this study highlight the importance of iron availability in limiting early season Ross Sea phytoplankton growth and suggest that rates of vitamin B12 production and consumption may be impacted by iron availability. PMID:21886638

Bertrand, Erin M.; Saito, Mak A.; Lee, Peter A.; Dunbar, Robert B.; Sedwick, Peter N.; DiTullio, Giacomo R.

2011-01-01

53

Positive newborn screen for methylmalonic aciduria identifies the first mutation in TCblR/CD320, the gene for cellular uptake of transcobalamin-bound vitamin B(12).  

PubMed

Elevated methylmalonic acid in five asymptomatic newborns whose fibroblasts showed decreased uptake of transcobalamin-bound cobalamin (holo-TC), suggested a defect in the cellular uptake of cobalamin. Analysis of TCblR/CD320, the gene for the receptor for cellular uptake of holo-TC, identified a homozygous single codon deletion, c.262_264GAG (p.E88del), resulting in the loss of a glutamic acid residue in the low-density lipoprotein receptor type A-like domain. Inserting the codon by site-directed mutagenesis fully restored TCblR function. PMID:20524213

Quadros, Edward V; Lai, Shao-Chiang; Nakayama, Yasumi; Sequeira, Jeffrey M; Hannibal, Luciana; Wang, Sihe; Jacobsen, Donald W; Fedosov, Sergey; Wright, Erica; Gallagher, Renata C; Anastasio, Natascia; Watkins, David; Rosenblatt, David S

2010-08-01

54

Antiparasitic Effect of Vitamin B12 on Trypanosoma cruzi  

PubMed Central

A nutritional characteristic of trypanosomatid protozoa is that they need a heme compound as a growth factor. Because of the cytotoxic activity of heme and its structural similarity to cobalamins, we have investigated the in vitro and in vivo effect of vitamin B12 (or cyanocobalamin) on the different forms of Trypanosoma cruzi. Cyanocobalamin showed a marked antiparasitic activity against epimastigotes (50% inhibitory concentration [IC50], 2.42 ?M), amastigotes (IC50, 10.69 ?M), and trypomastigotes (IC50, 9.46 ?M). Anti-epimastigote and -trypomastigote values were 1.7 to 4 times lower than those obtained with the reference drug benznidazole (Bnz). We also found that B12 and hemin do not interact with each other in their modes of action. Our results show that B12 increases intracellular oxidative activity and stimulates both superoxide dismutase (50%) and ascorbate peroxidase (20%) activities, while the activity of trypanothione reductase was not modified. In addition, we found that the antioxidants dithiothreitol and ascorbic acid increase the susceptibility of the parasite to the cytotoxic action of B12. We propose that vitamin B12 exerts its growth-inhibitory effect through the generation of reactive oxygen species. In an in vivo assay, a significant reduction in the number of circulating parasites was found in T. cruzi-infected mice treated with cyanocobalamin and ascorbic acid. The reduction of parasitemia in benznidazole-treated mice was improved by the addition of these vitamins. According to our results, a combination of B12 and Bnz should be further investigated due to its potential as a new therapeutic modality for the treatment of Chagas' disease. PMID:22869565

Ciccarelli, Alejandra B.; Frank, Fernanda M.; Puente, Vanesa; Malchiodi, Emilio L.

2012-01-01

55

Vitamin B12 deficiency among patients with diabetes mellitus: is routine screening and supplementation justified?  

PubMed Central

Vitamin B12 is an essential micronutrient required for optimal hemopoetic, neuro-cognitive and cardiovascular function. Biochemical and clinical vitamin B12 deficiency has been demonstrated to be highly prevalent among patients with type 1 and type 2 diabetes mellitus. It presents with diverse clinical manifestations ranging from impaired memory, dementia, delirium, peripheral neuropathy, sub acute combined degeneration of the spinal cord, megaloblastic anemia and pancytopenia. This review article offers a current perspective on the physiological roles of vitamin B12, proposed pathophysiological mechanisms of vitamin B12 deficiency, screening for vitamin B12 deficiency and vitamin B12 supplementation among patients with diabetes mellitus. PMID:23651730

2013-01-01

56

Vitamin B12 is the active corrinoid produced in cultivated white button mushrooms (Agaricus bisporus).  

PubMed

Analysis of vitamin B(12) in freshly harvested white button mushrooms ( Agaricus bisporus ) from five farms was performed by affinity chromatography and HPLC-ESI-MS techniques. The vitamin B(12) concentrations obtained varied from farm to farm, with higher concentrations of vitamin B(12) detected in outer peel than in cap, stalk, or flesh, suggesting that the vitamin B(12) is probably bacteria-derived. High concentrations of vitamin B(12) were also detected in the flush mushrooms including cups and flats. HPLC and mass spectrometry showed vitamin B(12) retention time and mass spectra identical to those of the standard vitamin B(12) and those of food products including beef, beef liver, salmon, egg, and milk but not of the pseudovitamin B(12), an inactive corrinoid in humans. The results suggest that the consumer may benefit from the consumption of mushroom to increase intake of this vitamin in the diet. PMID:19552428

Koyyalamudi, Sundar Rao; Jeong, Sang-Chul; Cho, Kai Yip; Pang, Gerald

2009-07-22

57

Algae acquire vitamin B12 through a symbiotic relationship with bacteria  

Microsoft Academic Search

Vitamin B12 (cobalamin) was identified nearly 80years ago as the anti-pernicious anaemia factor in liver, and its importance in human health and disease has resulted in much work on its uptake, cellular transport and utilization. Plants do not contain cobalamin because they have no cobalamin-dependent enzymes. Deficiencies are therefore common in strict vegetarians, and in the elderly, who are susceptible

Martin T. Croft; Andrew D. Lawrence; Evelyne Raux-Deery; Martin J. Warren; Alison G. Smith

2005-01-01

58

Negative symptoms presenting as neuropsychiatric manifestation of vitamin B12 deficiency  

PubMed Central

Long lists of psychiatric illness or symptoms have been documented to be caused by vitamin B12 deficiency. We describe an atypical case of a young adult who presented with predominant negative symptoms followed by neurological symptoms consistent with vitamin B12 deficiency. The symptoms showed complete remission after vitamin B12 supplementation. The uniqueness of this case is that vitamin B12 deficiency presented with predominant negative symptoms without other psychotic and manic symptoms, which has not been reported previously. PMID:22303049

Sahoo, Manoj Kumar; Avasthi, Ajit; Singh, Parampreet

2011-01-01

59

Dose-response effects of long-acting injectable vitamin B12 plus selenium (Se) on the vitamin B12 and Se status of ewes and their lambs  

Microsoft Academic Search

AIM: To determine the effect of increasing doses of long-acting injectable vitamin B12 plus selenium (Se) given pre-mating on the vitamin B12 and Se status of ewes and their lambs from birth to weaning.METHODS: Four groups of 24 Poll Dorset ewes each were injected 4 weeks pre-mating with different doses of a long-acting vitamin B12 + Se product, containing 3

ND Grace; SO Knowles

2006-01-01

60

Folate, vitamin B12 and postmenopausal breast cancer in a prospective study of French women.  

E-print Network

Folate, vitamin B12 and postmenopausal breast cancer in a prospective study of French women. Martin and examine whether the relation is affected by alcohol and intake of vitamin B2 and B12. Methods intake. The decreasing trend was most marked in women with higher folate and vitamin B12 intake. However

Paris-Sud XI, Université de

61

Biologically active vitamin B12 compounds in foods for preventing deficiency among vegetarians and elderly subjects.  

PubMed

The usual dietary sources of vitamin B12 are animal-source based foods, including meat, milk, eggs, fish, and shellfish, although a few plant-based foods such as certain types of dried lavers (nori) and mushrooms contain substantial and considerable amounts of vitamin B12, respectively. Unexpectedly, detailed characterization of vitamin B12 compounds in foods reveals the presence of various corrinoids that are inactive in humans. The majority of edible blue-green algae (cyanobacteria) and certain edible shellfish predominately contain an inactive corrinoid known as pseudovitamin B12. Various factors affect the bioactivity of vitamin B12 in foods. For example, vitamin B12 is partially degraded and loses its biological activity during cooking and storage of foods. The intrinsic factor-mediated gastrointestinal absorption system in humans has evolved to selectively absorb active vitamin B12 from naturally occurring vitamin B12 compounds, including its degradation products and inactive corrinoids that are present in daily meal foods. The objective of this review is to present up-to-date information on various factors that can affect the bioactivity of vitamin B12 in foods. To prevent vitamin B12 deficiency in high-risk populations such as vegetarians and elderly subjects, it is necessary to identify plant-source foods that contain high levels of bioactive vitamin B12 and, in conjunction, to prepare the use of crystalline vitamin B12-fortified foods. PMID:23782218

Watanabe, Fumio; Yabuta, Yukinori; Tanioka, Yuri; Bito, Tomohiro

2013-07-17

62

Vitamin B-12 supplementation during pregnancy and early lactation increases maternal, breast milk, and infant measures of vitamin B-12 status.  

PubMed

Pregnant women in resource-poor areas are at risk of multiple micronutrient deficiencies, and indicators of low vitamin B-12 status have been associated with adverse pregnancy outcomes, including anemia, low birth weight, and intrauterine growth retardation. To evaluate whether daily oral vitamin B-12 supplementation during pregnancy increases maternal and infant measures of vitamin B-12 status, we performed a randomized, placebo-controlled clinical trial. Pregnant women <14 wk of gestation in Bangalore, India, were randomly assigned to receive daily oral supplementation with vitamin B-12 (50 ?g) or placebo through 6 wk postpartum. All women were administered iron and folic acid supplements throughout pregnancy. One hundred eighty-three women were randomly assigned to receive vitamin B-12 and 183 to receive placebo. Compared with placebo recipients, vitamin B-12-supplemented women had significantly higher plasma vitamin B-12 concentrations at both the second (median vitamin B-12 concentration: 216 vs. 111 pmol/L, P < 0.001) and third (median: 184 vs. 105 pmol/L, P < 0.001) trimesters. At 6 wk postpartum, median breast milk vitamin B-12 concentration was 136 pmol/L in vitamin B-12-supplemented women vs. 87 pmol/L in the placebo group (P < 0.0005). Among vitamin B-12-supplemented women, the incidence of delivering an infant with intrauterine growth retardation was 33 of 131 (25%) vs. 43 of 125 (34%) in those administered placebo (P = 0.11). In a subset of infants tested at 6 wk of age, median plasma vitamin B-12 concentration was 199 pmol/L in those born to supplemented women vs. 139 pmol/L in the placebo group (P = 0.01). Infant plasma methylmalonic acid and homocysteine concentrations were significantly lower in the vitamin B-12 group as well. Oral supplementation of urban Indian women with vitamin B-12 throughout pregnancy and early lactation significantly increases vitamin B-12 status of mothers and infants. It is important to determine whether there are correlations between these findings and neurologic and metabolic functions. This trial was registered at clinicaltrials.gov as NCT00641862. PMID:24598885

Duggan, Christopher; Srinivasan, Krishnamachari; Thomas, Tinku; Samuel, Tinu; Rajendran, Ramya; Muthayya, Sumithra; Finkelstein, Julia L; Lukose, Ammu; Fawzi, Wafaie; Allen, Lindsay H; Bosch, Ronald J; Kurpad, Anura V

2014-05-01

63

Psychotic disorder and extrapyramidal symptoms associated with vitamin B12 and folate deficiency.  

PubMed

Vitamin B12 and folate deficiency causing neuropsychiatric and thrombotic manifestations, such as peripheral neuropathy, subacute combined degeneration of cord, dementia, ataxia, optic atrophy, catatonia, psychosis, mood disturbances, myocardial infarction and portal vein thrombosis are well known. This present report highlights an unusual presentation of vitamin B12 deficiency-psychotic disorder, extrapyramidal symptoms in a 12-year-old boy. His symptoms responded to parenteral vitamin B12 therapy. So with this report we emphasized that serum vitamin B12 and folate levels should be measured, especially in those patients who present with other known neuropsychiatric features of vitamin B12 and folate deficiency. PMID:19095695

Dogan, Murat; Ozdemir, Osman; Sal, Ertan A; Dogan, S Zehra; Ozdemir, Pinar; Cesur, Yasar; Caksen, Hüseyin

2009-06-01

64

B vitamin therapy for homocysteine: renal function and vitamin B12 determine cardiovascular outcomes.  

PubMed

Therapy to lower homocysteine with B vitamins does reduce the risk of stroke, if not myocardial infarction. The apparent lack of efficacy of vitamin therapy in most of the large clinical trials was probably determined by the failure to take account of the metabolic deficiency of vitamin B12, which is very common and often missed, and by the failure to take account of impaired renal function. Metabolic B12 deficiency is present in 20% of people over 65 years of age, and in 30% of vascular patients above 70 years, so higher doses of B12 are needed in elderly patients. However, high-dose cyanocobalamin leads to accumulation of cyanide in patients with renal failure. B vitamin therapy is beneficial in patients with good renal function, but harmful in patients with significantly impaired renal function (a glomerular filtration rate <50). It seems likely that in patients with renal impairment, methylcobalamin should be used instead cyanocobalamin. PMID:23449527

Spence, John David

2013-03-01

65

Combined dietary folate, vitamin B-12, and vitamin B-6 intake influences plasma docosahexaenoic acid concentration in rats  

E-print Network

Background: Folate, vitamin B-12, and vitamin B-6 are essential nutritional components in one-carbon metabolism and are required for methylation capacity. The availability of these vitamins may therefore modify methylation ...

van Wijk, Nick

66

Effects of vitamin B12, folate, and vitamin B6 supplements in elderly people with normal serum vitamin concentrations  

Microsoft Academic Search

SummaryIn a prospective, multicentre, double-blind controlled study, the effect of an intramuscular vitamin supplement containing 1 mg vitamin B12, 1·1 mg folate, and 5 mg vitamin B6 on serum concentrations of methylmalonic acid (MMA), homocysteine (HCYS), 2-methylcitric acid (2-MCA), and cystathionine (CYSTA) was compared with that of placebo in 175 elderly subjects living at home and 110 in hospital. Vitamin

H. J. Naurath; E. Joosten; R. Riezler; S. Stabler; R. H. Allen; J. Lindenbaum

1995-01-01

67

Insights into the Evolution of Vitamin B12 Auxotrophy from Sequenced Algal Genomes  

E-print Network

Insights into the Evolution of Vitamin B12 Auxotrophy from Sequenced Algal Genomes Katherine E Abstract Vitamin B12 (cobalamin) is a dietary requirement for humans because it is an essential cofactor microalgal species need the vitamin as a growth supplement, but there is no phylogenetic relationship between

Goldstein, Raymond E.

68

Metformin-induced vitamin B12 deficiency presenting as a peripheral neuropathy.  

PubMed

Chronic metformin use results in vitamin B12 deficiency in 30% of patients. Exhaustion of vitamin B12 stores usually occurs after twelve to fifteen years of absolute vitamin B12 deficiency. Metformin has been available in the United States for approximately fifteen years. Vitamin B12 deficiency, which may present without anemia and as a peripheral neuropathy, is often misdiagnosed as diabetic neuropathy, although the clinical findings are usually different. Failure to diagnose the cause of the neuropathy will result in progression of central and/or peripheral neuronal damage which can be arrested but not reversed with vitamin B12 replacement. To my knowledge, this is the first report of metformin-induced vitamin B12 deficiency causing neuropathy. PMID:20134380

Bell, David S H

2010-03-01

69

Update: vitamin B12 deficiency among Bhutanese refugees resettling in the United States, 2012.  

PubMed

In 2008, clinicians performing routine medical examinations in the United States reported high rates of hematologic and neurologic disorders caused by vitamin B12 deficiency in resettled Bhutanese refugees. To confirm this finding, CDC screened Bhutanese refugees' serum samples for vitamin B12 levels and found vitamin B12 deficiency in 64% (n = 99) of samples obtained before departure and 27% (n = 64) of samples obtained after arrival in the United States. In response, CDC recommended that arriving Bhutanese refugees receive oral vitamin B12 supplements and nutrition advice. In 2012, based on anecdotal reports of decreasing rates of vitamin B12 deficiency in this population, CDC worked with select domestic refugee health programs to determine if the recommendations had reduced the vitamin B12 deficiency rate among Bhutanese refugees. PMID:25029113

Cuffe, Kendra; Stauffer, William; Painter, John; Shetty, Sharmila; Montour, Jessica; Zhou, Weigong

2014-07-18

70

Biomarkers of vitamin B-12 status in NHANES: a roundtable summary123456  

PubMed Central

A roundtable to discuss the measurement of vitamin B-12 (cobalamin) status biomarkers in NHANES took place in July 2010. NHANES stopped measuring vitamin B-12–related biomarkers after 2006. The roundtable reviewed 3 biomarkers of vitamin B-12 status used in past NHANES—serum vitamin B-12, methylmalonic acid (MMA), and total homocysteine (tHcy)—and discussed the potential utility of measuring holotranscobalamin (holoTC) for future NHANES. The roundtable focused on public health considerations and the quality of the measurement procedures and reference methods and materials that past NHANES used or that are available for future NHANES. Roundtable members supported reinstating vitamin B-12 status measures in NHANES. They noted evolving concerns and uncertainties regarding whether subclinical (mild, asymptomatic) vitamin B-12 deficiency is a public health concern. They identified the need for evidence from clinical trials to address causal relations between subclinical vitamin B-12 deficiency and adverse health outcomes as well as appropriate cutoffs for interpreting vitamin B-12–related biomarkers. They agreed that problems with sensitivity and specificity of individual biomarkers underscore the need for including at least one biomarker of circulating vitamin B-12 (serum vitamin B-12 or holoTC) and one functional biomarker (MMA or tHcy) in NHANES. The inclusion of both serum vitamin B-12 and plasma MMA, which have been associated with cognitive dysfunction and anemia in NHANES and in other population-based studies, was preferable to provide continuity with past NHANES. Reliable measurement procedures are available, and National Institute of Standards and Technology reference materials are available or in development for serum vitamin B-12 and MMA. PMID:21593512

Pfeiffer, Christine M; Phinney, Karen W; Bailey, Regan L; Blackmore, Sheena; Bock, Jay L; Brody, Lawrence C; Carmel, Ralph; Curtin, L Randy; Durazo-Arvizu, Ramon A; Eckfeldt, John H; Green, Ralph; Gregory, Jesse F; Hoofnagle, Andrew N; Jacobsen, Donald W; Jacques, Paul F; Lacher, David A; Molloy, Anne M; Massaro, Joseph; Mills, James L; Nexo, Ebba; Rader, Jeanne I; Selhub, Jacob; Sempos, Christopher; Shane, Barry; Stabler, Sally; Stover, Patrick; Tamura, Tsunenobu; Tedstone, Alison; Thorpe, Susan J; Johnson, Clifford L; Picciano, Mary Frances

2011-01-01

71

[Vitamin B12-level in serum of diabetics receiving long-term buformin therapy].  

PubMed

Disturbances of the vitamin B12 resorption by the therapy with biguanides above all metformin are known from literature. In 59 patients with Buformin retard-monotherapy we determined in 18.7% slight reductions of the vitamin B12 level in the serum, in one patient the serum concentration was lower than 50 pg/ml. That means that also under therapy with Buformin can be reckoned with easy disturbances of resorption for vitamin B12. Occasional controls of Hb and anamnestic establishment of neurological symptoms are to be recommended during a therapy with Buformin, in order not to overlook the clinical signs of a vitamin B12 hypovitaminosis. PMID:7257460

Müller, P; Fischer, H; Sorger, D

1981-03-15

72

Laboratory Evaluation for Vitamin B12 Deficiency: The Case for Cascade Testing  

PubMed Central

Objective Potential vitamin B12 deficiency is a common clinical diagnostic problem, and many providers have a low threshold for initiating therapy. The goal of this study was to systematically evaluate current practice patterns regarding the laboratory evaluation of suspected vitamin B12 deficiency. Methods This retrospective study reviewed the electronic medical records of 192 patients initiated on intramuscular vitamin B12 injections. Results Only 12 patients had objectively documented hematologic responses: decrease of mean corpuscular volume by ?5 fL with stable or improved hemoglobin. Another 5 patients had equivocal hematologic responses. There was one plausible neurologic response. Thus, only 18 (9.4%) of 192 patients had data supportive of a clinical response. In these 18 patients, the baseline serum B12 level was ?107 pg/mL; only 3 patients also had a baseline serum methylmalonic acid level, which was ?1.29 ?mol/L in all 3 patients. Conclusions Currently, only a small minority of patients initiated on intramuscular vitamin B12 supplementation derive any meaningful clinical benefit. Furthermore, current testing recommendations for vitamin B12 deficiency are usually not followed. Up-front ordering of a diagnostic testing cascade is recommended to improve compliance; an example is presented with decision points chosen to improve specificity for clinically evident vitamin B12 deficiency without loss of sensitivity. Ultimately, a better understanding of vitamin B12 physiology is needed to develop and evaluate laboratory tests that more accurately reflect true intracellular vitamin B12 status. PMID:23262189

Berg, Richard L.; Shaw, Gene R.

2013-01-01

73

Daily milk intake improves vitamin B-12 status in young vegetarian Indians: an intervention trial  

PubMed Central

Background Asymptomatic Indian lacto vegetarians, who make up more than half of the Indian population in different geographic regions, have distinctly low vitamin B-12 concentrations than non- vegetarians. Vegetarians consume milk but it seems that the amount is not enough to improve vitamin B-12 status or vitamin B-12 concentration in milk itself may be low. The aim of this study was to determine if daily milk consumption can improve vitamin B-12 status. Methods Fifteen male and 36 female, young healthy post-graduate volunteers participated. Blood from ten participants (4 males and 6 females) was collected (day-1). They continued their regular diet for next fourteen days and on day-15, blood of all 51 participants was collected, plasma vitamin B-12 concentration was measured and were divided into two groups; Normal (vitamin B-12 >148 pmol/L, n?=?22) and Vitamin B-12 deficient (<148 pmol/L, n?=?29), the remaining plasma was stored. All participants consumed 600 ml. of non-enriched buffalo milk (200 × 3) during the day along with their usual diet. Next day blood was collected for plasma holotranscobalamin II measurement. Subjects from deficient group continued to drink 400 ml of milk daily for next 14 days and blood was collected on day-30. Plasma holotranscoabalamin II (day-1, 15, 16, 30), vitamin B-12, folate, total homocysteine, creatinine and hematoloical parameters (day-1, 15, 30), and milk vitamin B-12 concentrations (day-15, 16, 30) were measured. Results Fifty seven per cent of the participants were vitamin B-12 deficient and 65% were hyperhomocysteinemic. No significant difference in biomarkers was observed when there was no intervention. Plasma holotranscobalamin II concentration increased from 19.6 to 22.27 pmol/L (p?vitamin B-12 increased from 92.5 to 122 pmol/L and tHcy concentrations decreased from 31.9 to 24.9 ? mol/L (p?vitamin B-12 deficient subjects. Conclusions Regular intake of milk improved vitamin B-12 status of vitamin B-12 deficient vegetarians indicating a potential dietary strategy to improve the vitamin status. PMID:24107225

2013-01-01

74

The effect of sporidesmin toxicity on ovine serum vitamin B12 levels.  

PubMed

A field outbreak of facial eczema occurred during a vitamin B12 response trial in young growing sheep. Pasture cobalt levels were in the low range for sheep (<0.08 mg/kg, 1.358 micromol/kg) and mean (of 3) liver vitamin B12 levels in the sheep were low (<400 nmol/kg) during the period in which facial eczema occurred. Mean serum vitamin B12 levels of the untreated group were low (<485 pmol/l) for the two months (January and February) preceding the period of facial eczema. However, levels showed an approximate 3.5 fold increase in both cobalt supplemented and unsupplemented groups with the onset of facial eczema in March. From February to March the mean serum vitamin B12 and glutamyl transferase (GGT) activity showed parallel increases with a positive correlation (r = 0.73) between log serum vitamin B12 and log serum GGT activity during the period January to July for both groups. This finding suggested that the increase in serum vitamin B12 was due to sporidesmin induced liver damage. The diagnostic implication is that, in areas where facial eczema is a problem, liver is the sample of choice for determining vitamin B12 status. because sporidesmin toxicity can elevate low serum vitamin B12 levels to diagnostically normal levels. PMID:16031439

Clark, R G; Duganzich, D M; Mortleman, L; Fraser, A J

1988-06-01

75

Long term use of metformin leading to vitamin B 12 deficiency.  

PubMed

Metformin is a commonly used oral hypoglycaemic agent worldwide. Gastrointestinal side effects and lactic acidosis related to metformin usage are commonly recognized. However, the associated vitamin B12 deficiency is less well known. We present a case of long term metformin use resulting in vitamin B12 deficiency. PMID:24674102

Tung, Moon Ley; Tan, Lip Kun

2014-06-01

76

The effect of vitamin B 12 on the reverse development of cholesterol atherosc lerosis in rabbits  

Microsoft Academic Search

Prolonged vitamin B12 administration promotes reverse development of atheromatous elements in the rabbit aorta, affected by cholesterol atherosclerosis. Evidently, accelerated reverse development of choloesterol atherosclerosis is connected with the action of vitamin B12 upon the concentration of the lipids in the blood serum.

L. N. Ignatova

1961-01-01

77

Vitamin B-12 and homocysteine status among vegetarians: a global perspective.  

PubMed

Evidence exists that well-planned vegetarian diets provide numerous health benefits and are appropriate for all stages of the life cycle. It is also known that animal foods provide micronutrients that are nonexistent or available only in limited amounts in plant foods. Restriction or exclusion of all animal foods may therefore result in low intake of certain micronutrients such as vitamin B-12, thereby affecting vitamin B-12 status and elevating plasma homocysteine concentrations. Overall, the studies we reviewed showed reduced mean vitamin B-12 status and elevated mean homocysteine concentrations in vegetarians, particularly among vegans. Low vitamin B-12 intake may lead to decreased bioavailability and functional deficiency of cobalamin. Although early noticeable symptoms of vitamin B-12 deficiency are nonspecific (unusual fatigue, digestion problems, frequent upper respiratory infections), the best-known clinical manifestations of cobalamin malabsorption are hematologic (pernicious anemia) and neurologic symptoms. Hyperhomocysteinemia is associated with an increased risk of atherosclerosis and cardiovascular disease. Given these health concerns, vegetarians, particularly vegans, must be advised to carefully plan their diets, to monitor their plasma vitamin B-12 on a regular basis to facilitate early detection of low cobalamin status, and to use vitamin B-12-fortified foods or take vitamin B-12 supplements if necessary. PMID:19357223

Elmadfa, Ibrahim; Singer, Ingrid

2009-05-01

78

Vitamin B12 deficiency, hyperhomocysteinemia and thrombosis: a case and control study  

Microsoft Academic Search

This study aimed at assessing the relationship between thrombosis, hyperhomocysteinemia and vitamin B12 deficiency using a\\u000a case–control study carried out in 326 patients with thrombosis (case group) and 351 patients from the same hospital (control\\u000a group). Apart from the classic risk factors, a number of hematological variables were evaluated, including serum vitamin B12\\u000a (B12), red cell folate (RCF), and serum

Angel F. Remacha; Joan Carles Souto; José Luis Piñana; María Pilar Sardà; Josep Maria Queraltó; Joan Martí-Fabregas; Xavier García-Moll; Cristina Férnandez; Alvaro Rodriguez; Jorge Cuesta

2011-01-01

79

Über das Vitamin B 12 -Bedürfnis phototropher Schwefelbakterien  

Microsoft Academic Search

1.10 von 19 Chlorobium-Stämmen, die mit einer Vit. B12-haltigen Nährlösung aus verschiedenen Gewässern in Kalifornien, Norwegen und Deutschland isoliert waren, erwiesen sich als Vit. B12-bedürftig.2.Bei Vit. B12-bedürftigen Chlorobium- und Chromatium-Stämmen wurde der Chlorophyllgehalt der Kulturen in Abhängigkeit von der Vit. B12-Konzentration quantitativ bestimmt. Zur Bildung vergleichbarer Erträge benötigten alle untersuchten Chlorobium-Stämme gegenüber den Chromatium-Stämmen etwa zehnmal höhere Vit. B12-Konzentrationen.3.Der Vergleich

Norbert Pfennig; Klaus Dieter Lippert

1966-01-01

80

Chemometrics assisted spectroscopic determination of vitamin B6, vitamin B12 and dexamethasone in injectables  

Microsoft Academic Search

A spectrophotometric method is described and applied to resolve ternary mixtures of the corticosteroid dexamethasone sodium phosphate and the vitamins B6 and B12. It involves multivariate calibration based on partial least-squares regression. The model was built with UV–vis absorption spectra, and was evaluated by cross-validation on a number of synthetic mixtures. Satisfactory results for both artificial and commercial samples were

Alberto J. Nepote; Patricia C. Damiani; Alejandro C. Olivieri

2003-01-01

81

Vitamin B12 and ageing: current issues and interaction with folate.  

PubMed

A compromised vitamin B12 status is common in older people despite dietary intakes that typically far exceed current recommendations. The maintenance of an optimal status of vitamin B12 is not only dependent on adequate dietary intake but more critically on effective absorption which diminishes with age. The measurement of vitamin B12 is complicated by the lack of a gold standard assay. There are a number of direct and functional indicators of vitamin B12 status; however, none of these are without limitations and should be used in combination. Vitamin B12 is of public health importance, not only because deficiency leads to megaloblastic anaemia and irreversible nerve damage, but also because emerging evidence links low B12 to an increased risk of a number of age-related diseases, including cardiovascular disease, cognitive dysfunction, dementia and osteoporosis. Furthermore, there are concerns relating to potential adverse effects for older adults with low vitamin B12 status of over-exposure to folic acid in countries where there is mandatory fortification of food with folic acid. The aim of this review is to examine the known and emerging issues related to vitamin B12 in ageing, its assessment and inter-relationship with folate. PMID:23592803

Hughes, Catherine F; Ward, Mary; Hoey, Leane; McNulty, Helene

2013-07-01

82

Vitamin B12 deficiency in resettled Bhutanese refugees--United States, 2008-2011.  

PubMed

Since 2008, approximately 30,000 Bhutanese refugees have been resettled in the United States. Routine medical examinations of refugees after arrival in resettlement states indicated hematologic and neurologic disorders caused by vitamin B12 deficiency. These cases were reported by examining physicians and state health departments to CDC, which initiated an investigation. This report summarizes the results of that investigation. Sera from overseas medical examinations, postarrival examinations in three state health departments (Minnesota, Utah, and Texas), and medical records and interviews at a health clinic in St. Paul, Minnesota, were evaluated. Vitamin B12 deficiency, defined as serum vitamin B12 concentration <203 pg/mL, was found in 64% (63 of 99) of overseas specimens, 27% (17 of 64) of postarrival medical screenings, and 32% (19 of 60) of Bhutanese refugees screened for vitamin B12 deficiency at the St. Paul clinic. Although the deficiencies might be multifactorial, the main cause is thought to be the diet consumed by these refugees for nearly two decades in Nepal, which lacked meat, eggs, and dairy products, the major dietary sources of vitamin B12. Additionally, infection with Helicobacter pylori might play a role. Clinicians should be aware of the risk for vitamin B12 deficiency in Bhutanese refugees. All Bhutanese refugees should be given nutrition advice and should receive supplemental vitamin B12 upon arrival in the United States. In addition, refugees with clinical manifestations suggestive of deficiency should be tested for adequate serum vitamin B12 concentrations and, if found to have a B12 deficiency, screened for underlying causes, treated with parenteral vitamin B12 or high-dose oral supplements, and evaluated for response to therapy. PMID:21430638

2011-03-25

83

Vitamin B12 levels in ewe colostrum and milk and in lamb serum  

E-print Network

Short note Vitamin B12 levels in ewe colostrum and milk and in lamb serum JJ Ramos T Saez JP Bueso 1993; accepted 4 February 1994) Summary ― Vitamin B!2 was measured in samples of normal ovine d. Colostrum obtained within 24 h of lambing contained high concentrations of vitamin B!2

Paris-Sud XI, Université de

84

Hyperhomocysteinemia in chronic alcoholism: relations to folic acid and vitamins b 6 and b 12 status  

Microsoft Academic Search

The objective of this review is to present and discuss the current perspectives of homocysteine and one carbon metabolism in chronic alcoholism. Chronic alcoholics frequently suffer from specific micronutrient deficiencies, including vitamins involved in one carbon metabolism, i.e., folate, vitamin B6 and vitamin B12. The possible link between homocysteine and alcoholism stems from the fact that homocysteine metabolism is closely

Mar??lia L Cravo; Maria E Camilo

2000-01-01

85

Optimizing vitamin B 12 biosynthesis by mycelial cultures of Lentinula edodes (Berk.) Pegl  

Microsoft Academic Search

Preparations derived from Lentinula edodes (Berk.) Pegl. are widely used as dietary supplements, they contain compounds with immune system enhancing and chemopreventive properties. These preparations contain a blend of minerals and vitamins, including vitamins A, D, B1, B2, C, and niacin, but only scant vitamin B12. Our goal was to optimize the growth conditions of submerged mycelial cultures of L.

J. Tur?o; B. Gutkowska; F. Herold; W. Krzyczkowski; A. B?a?ewicz; R. Kocjan

2008-01-01

86

Most harmful algal bloom species are vitamin B1 and B12 auxotrophs  

PubMed Central

Eutrophication can play a central role in promoting harmful algal blooms (HABs), and therefore many HAB studies to date have focused on macronutrients (N, P, Si). Although a majority of algal species require exogenous B vitamins (i.e., auxotrophic for B vitamins), the possible importance of organic micronutrients such as B vitamins (B1, B7, B12) in regulating HABs has rarely been considered. Prior investigations of vitamins and algae have examined a relatively small number of dinoflagellates (n = 26) and a paucity of HAB species (n = 4). In the present study, the vitamin B1, B7, and B12 requirements of 41 strains of 27 HAB species (19 dinoflagellates) were investigated. All but one species (two strains) of harmful algae surveyed required vitamin B12, 20 of 27 species required B1, and 10 of 27 species required B7, all proportions higher than the previously reported for non-HAB species. Half-saturation (Ks) constants of several HAB species for B1 and B12 were higher than those previously reported for other phytoplankton and similar to vitamin concentrations reported in estuaries. Cellular quotas for vitamins suggest that, in some cases, HAB demands for vitamins may exhaust standing stocks of vitamins in hours to days. The sum of these findings demonstrates the potentially significant ecological role of B-vitamins in regulating the dynamics of HABs. PMID:21068377

Tang, Ying Zhong; Koch, Florian; Gobler, Christopher J.

2010-01-01

87

The effects of vitamins C and B12 on human nasal ciliary beat frequency  

PubMed Central

Background This study was designed to investigate the effects of the vitamins C and B12 on the regulation of human nasal ciliary beat frequency (CBF). Methods Human nasal mucosa was removed endoscopically and nasal ciliated cell culture was established. Changes of CBF in response to different concentrations of vitamin C or vitamin B12 were quantified by using high-speed (240 frames per second) digital microscopy combined with a beat-by-beat CBF analysis. Results At the concentrations of 0.01% and 0.10%, vitamin C induced an initial increase, followed by a gradual decrease of CBF to the baseline level, while 1.00% vitamin C induced a reversible decrease of CBF. Vitamin B12, at the concentrations of 0.01% and 0.10%, did not influence CBF during the 20-min observation period, while a 1.00% vitamin B12 treatment caused a time-dependent but reversible decrease of CBF. Conclusions Treatment with vitamin C or vitamin B12 caused a concentration-dependent but reversible decrease of CBF in cultured human nasal epithelial cells. Therefore, it is necessary to choose a concentration that is safe, effective, and non-ciliotoxic when applying these drugs topically in the nasal cavity. PMID:23688196

2013-01-01

88

Oral vitamin B12 for patients suspected of subtle cobalamin deficiency: a multicentre pragmatic randomised controlled trial  

Microsoft Academic Search

BACKGROUND: Evidence regarding the effectiveness of oral vitamin B12 in patients with serum vitamin B12 levels between 125-200 pM\\/l is lacking. We compared the effectiveness of one-month oral vitamin B12 supplementation in patients with a subtle vitamin B12 deficiency to that of a placebo. METHODS: This multicentre (13 general practices, two nursing homes, and one primary care center in western

Bernard Favrat; Paul Vaucher; Lilli Herzig; Bernard Burnand; Giuseppa Ali; Olivier Boulat; Thomas Bischoff; François Verdon

2011-01-01

89

Folate and vitamin B12 status of a multiethnic adult population.  

PubMed Central

BACKGROUND: Folic acid and vitamin B12 are of particular interest for their diverse biological functions and preventive roles in many prevalent chronic diseases. However, ethnic differences on the status of these vitamins have not been investigated among multiethnic adult college students. METHODS: A cross-sectional study (n = 177) was conducted to determine the dietary intakes and levels of serum concentrations of folate and vitamin B12 among triethnic college students-non-Hispanic white, Hispanic and non-Hispanic black. Dietary intake was assessed using a validated food frequency questionnaire, and serum was analyzed for folate and vitamin B12 using standardized methods. RESULTS: Mean intakes of both vitamins without supplementation was higher (P < 0.05) among non-Hispanic white males than females, and non-Hispanic white and non-Hispanic black males and females. Non-Hispanic white females had a significantly lower mean dietary intake of vitamin B12 than the females of other ethnic groups (P < 0.01). There was a positive correlation between B12 intake and serum concentrations. More than 52% of the females did not meet the required folate intake of 400 microg/day. CONCLUSIONS: The data suggest that there was no difference in overall mean intake of folate and vitamin B12 or serum concentrations in regard to gender or ethnicity. One-fourth of the female subjects failed to meet the recommended folate intake when supplement was excluded. PMID:16532981

Nath, Subrata D.; Koutoubi, Samer; Huffman, Fatma G.

2006-01-01

90

Vitamin B12 absorption capacity in healthy children  

SciTech Connect

B12 absorption was investigated in 47 healthy children aged 7 months to 15.8 years (median 4.9 years). The patients had either recovered from giardiasis, the post-gastroenteritis syndrome, or had celiac disease in remission (treated with a gluten-free diet). The B12 absorption was measured by a double-isotope technique using /sup 57/CoB12 and /sup 51/CrCl/sub 3/, the latter being the inabsorbable marker. The radiation dose was minimal. The results were presented as fractional absorption of B12 (FAB12). Within the different age groups, the absorption test was performed by means of the following oral amounts of B12: 0- less than 1 year, 0.5 microgram; 1-3 years: 1.7 micrograms, 4-6 years, 2.5 micrograms; 7-10 years; 3.3 micrograms; and 11-15 years, 4.5 micrograms. When using these oral amounts of B12, the medians (and ranges) of FAB12 were found to be: 1-3 years (n = 18), 37% (16-80%); 4-6 years (n = 10), 27% (19-40%); 7-10 years (n = 9), 32% (21-44%); and 11-15 years (n = 8), 27% (19-59%). The FAB12 in two children aged 7 and 11 months was 31% and 32%, respectively. These results may be interpretated as reference values for B12 absorption in children. Further absorption tests were performed in seven children representing the four age groups from 1 to 15 years. When a high oral amount of B12 was given (i.e., three times the saturation dose), the FAB12 ranged from 0 to 20% (median 9%), whereas a low amount (i.e., one-ninth of the saturation dose) produced fractional absorptions from 65 to 82% (median 74%).

Hjelt, K.; Krasilnikoff, P.A.

1986-03-01

91

Cerebral Atrophy in a Vitamin B12-deficient Infant of a Vegetarian Mother  

PubMed Central

ABSTRACT In developed countries, vitamin B12 (cobalamin) deficiency usually occurs in children, exclusively breastfed ones whose mothers are vegetarian, causing low body stores of vitamin B12. The haematologic manifestation of vitamin B12 deficiency is pernicious anaemia. It is a megaloblastic anaemia with high mean corpuscular volume and typical morphological features, such as hyperlobulation of the nuclei of the granulocytes. In advanced cases, neutropaenia and thrombocytopaenia can occur, simulating aplastic anaemia or leukaemia. In addition to haematological symptoms, infants may experience weakness, fatigue, failure to thrive, and irritability. Other common findings include pallor, glossitis, vomiting, diarrhoea, and icterus. Neurological symptoms may affect the central nervous system and, in severe cases, rarely cause brain atrophy. Here, we report an interesting case, a 12-month old infant, who was admitted with neurological symptoms and diagnosed with vitamin B12 deficiency. PMID:25076673

Akin, Fatih; Caksen, Huseyin; Boke, Saltuk Bugra; Arslan, Sukru; Aygun, Serhat

2014-01-01

92

Association of vitamin B12 deficiency and metformin use in patients with type 2 diabetes.  

PubMed

We evaluated the prevalence of vitamin B12 deficiency and associated factors in type 2 diabetes patients using metformin. A total of 799 type 2 diabetes patients using metformin was enrolled. Vitamin B12 and folate levels were quantified by chemiluminescent enzyme immunoassay. Vitamin B12 deficiency was defined as vitamin B12 ? 300 pg/mL without folate deficiency (folate > 4 ng/mL). The prevalence of vitamin B12 deficiency in metformin-treated type 2 diabetes patients was 9.5% (n = 76), and the mean vitamin B12 level was 662.5 ± 246.7 pg/mL. Vitamin B12 deficient patients had longer duration of metformin use (P < 0.001) and higher daily metformin dose (P < 0.001) than non-deficient patients. Compared with daily metformin dose of ? 1,000 mg, the adjusted odds ratio for 1,000-2,000 mg, and ? 2,000 mg were 2.52 (95% CI, 1.27-4.99, P = 0.008) and 3.80 (95% CI, 1.82-7.92, P < 0.001). Compared with metformin use of < 4 yr, the adjusted odds ratios for 4-10 yr, and ? 10 yr were 4.65 (95% CI, 2.36-9.16, P < 0.001) and 9.21 (95% CI, 3.38-25.11, P < 0.001), respectively. In conclusion, our study indicates that patients with type 2 diabetes treated with metformin should be screened for vitamin B12 deficiency, especially at higher dosages (> 1,000 mg) and longer durations (? 4 yr) of treatment. PMID:25045229

Ko, Sun-Hye; Ko, Sun-Hee; Ahn, Yu-Bae; Song, Ki-Ho; Han, Kyung-Do; Park, Yong-Moon; Ko, Seung-Hyun; Kim, Hye-Soo

2014-07-01

93

Evaluation of vitamin B12 effects on DNA damage induced by paclitaxel.  

PubMed

Paclitaxel (PAC) is an anticancer drug that has been shown to generate free radicals leading to irreversible cell injury. Vitamin B12 has antioxidative properties and can protect DNA from free radicals. In this study, we examined the possible genotoxic effect of PAC on DNA as well as the possible protective effect of vitamin B12 on DNA damage induced by paclitaxel. Sister chromatid exchanges (SCEs), chromosomal aberrations (CAs) and 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels were measured in cultured human blood lymphocytes treated with PAC (10 µM) and/or vitamin B12 (2.7 mg/mL). Our results showed that PAC significantly increased the frequencies of SCEs (p < 0.001) and CAs (p < 0.001) in human blood lymphocytes, as compared to controls. These DNA damages, caused by PAC drug, were prevented by pretreatment of cells with vitamin B12. In addition, we showed that PAC induced an increase in 8-OHdG, a marker of oxidative DNA damage, and that this increase was prevented by vitamin B12. Vitamin B12 seems to protect against genotoxicity induced by PAC in human blood lymphocytes. PMID:24215581

Alzoubi, Karem; Khabour, Omar; Khader, Manal; Mhaidat, Nizar; Al-Azzam, Sayer

2014-07-01

94

Hyperhomocysteinemia, deep vein thrombosis and vitamin B12 deficiency in a metformin-treated diabetic patient.  

PubMed

Vitamin B12 deficiency may be induced by long-term use of metformin, which may in turn lead to hyperhomocysteinemia. Thus, hyperhomocysteinemia may increase the risk of vascular thrombosis in diabetic patients, when metformin is used and a homozygous methylenetetrahydrofolate reductase (MTHFR) C677T mutation is present. We report a 65-year-old Taiwanese diabetic woman who was treated with metformin for 6 years and who had suffered from swelling of the left lower extremity for 3 months. Ascending venography confirmed the diagnosis of proximal deep vein thrombosis, while hyperhomocysteinemia, megaloblastic anemia caused by vitamin B12 deficiency, and a homozygous C677T mutation of the MTHFR gene were also found. She had no identifiable venous thrombotic risk factors other than hyperhomocysteinemia, which seemed to be caused by both MTHFR C677T homozygous mutation and vitamin B12 deficiency. With the substitution of insulin injection for metformin, short-term supplement of vitamin B12, and anticoagulant therapy for the deep vein thrombosis, her anemia and hyperhomocysteinemia recovered rapidly. The deep vein thrombosis also responded well. Our findings highly suggested the role of metformin in causing vitamin B12 deficiency, which may serve as an additional risk factor for venous thrombosis in diabetic patients. Our report also highlights the need to check vitamin B12 levels during metformin treatment. PMID:17908667

Lin, Hsuan-Yu; Chung, Chih-Yuan; Chang, Cheng-Shyong; Wang, Ming-Lun; Lin, Jen-Shiou; Shen, Ming-Ching

2007-09-01

95

Human vitamin B12 absorption measurement by accelerator mass spectrometry using specifically labeled 14C-cobalamin  

PubMed Central

There is a need for an improved test of human ability to assimilate dietary vitamin B12. Assaying and understanding absorption and uptake of B12 is important because defects can lead to hematological and neurological complications. Accelerator mass spectrometry is uniquely suited for assessing absorption and kinetics of carbon-14 (14C)-labeled substances after oral ingestion because it is more sensitive than decay counting and can measure levels of 14C in microliter volumes of biological samples with negligible exposure of subjects to radioactivity. The test we describe employs amounts of B12 in the range of normal dietary intake. The B12 used was quantitatively labeled with 14C at one particular atom of the dimethylbenzimidazole (DMB) moiety by exploiting idiosyncrasies of Salmonella metabolism. To grow aerobically on ethanolamine, Salmonella enterica must be provided with either preformed B12 or two of its precursors, cobinamide and DMB. When provided with 14C-DMB specifically labeled in the C2 position, cells produced 14C-B12 of high specific activity (2.1 GBq/mmol, 58 mCi/mmol) (1 Ci = 37 GBq) and no detectable dilution of label from endogenous DMB synthesis. In a human kinetic study, a physiological dose (1.5 ?g, 2.2 kBq/59 nCi) of purified 14C-B12 was administered and showed plasma appearance and clearance curves consistent with the predicted behavior of the pure vitamin. This method opens new avenues for study of B12 assimilation. PMID:16585531

Carkeet, Colleen; Dueker, Stephen R.; Lango, Jozsef; Buchholz, Bruce A.; Miller, Joshua W.; Green, Ralph; Hammock, Bruce D.; Roth, John R.; Anderson, Peter J.

2006-01-01

96

Requirements of Cultured Mammalian Cells for Vitamin B12 and Biotin.  

National Technical Information Service (NTIS)

Eagle reported in 1955 and 1957 that eight vitamins were essential for the growth of most mammalian cells in culture. No evidence for requirement of vitamin B12 or of biotin was presented. Sanford and co-workers in 1963 and 1964 reported evidence for requ...

K. Higuchi

1969-01-01

97

Chronic Maternal Vitamin B12 Restriction Induced Changes in Body Composition & Glucose Metabolism in the Wistar Rat Offspring Are Partly Correctable by Rehabilitation  

PubMed Central

Maternal under-nutrition increases the risk of developing metabolic diseases. We studied the effects of chronic maternal dietary vitamin B12 restriction on lean body mass (LBM), fat free mass (FFM), muscle function, glucose tolerance and metabolism in Wistar rat offspring. Prevention/reversibility of changes by rehabilitating restricted mothers from conception or parturition and their offspring from weaning was assessed. Female weaning Wistar rats (n?=?30) were fed ad libitum for 12 weeks, a control diet (n?=?6) or the same with 40% restriction of vitamin B12 (B12R) (n?=?24); after confirming deficiency, were mated with control males. Six each of pregnant B12R dams were rehabilitated from conception and parturition and their offspring weaned to control diet. While offspring of six B12R dams were weaned to control diet, those of the remaining six B12R dams continued on B12R diet. Biochemical parameters and body composition were determined in dams before mating and in male offspring at 3, 6, 9 and 12 months of their age. Dietary vitamin B12 restriction increased body weight but decreased LBM% and FFM% but not the percent of tissue associated fat (TAF%) in dams. Maternal B12R decreased LBM% and FFM% in the male offspring, but their TAF%, basal and insulin stimulated glucose uptake by diaphragm were unaltered. At 12 months age, B12R offspring had higher (than controls) fasting plasma glucose, insulin, HOMA-IR and impaired glucose tolerance. Their hepatic gluconeogenic enzyme activities were increased. B12R offspring had increased oxidative stress and decreased antioxidant status. Changes in body composition, glucose metabolism and stress were reversed by rehabilitating B12R dams from conception, whereas rehabilitation from parturition and weaning corrected them partially, highlighting the importance of vitamin B12 during pregnancy and lactation on growth, muscle development, glucose tolerance and metabolism in the offspring. PMID:25398136

Kumar, Kalle Anand; Lalitha, Anumula; Reddy, Umakar; Chandak, Giriraj Ratan; Sengupta, Shantanu; Raghunath, Manchala

2014-01-01

98

Rare sensory and autonomic disturbances associated with vitamin B12 deficiency.  

PubMed

Vitamin B12 deficiency is an important nutritional disorder causing neurological manifestations of myelopathy, neuropathy and dementia. Sub-acute combined degeneration (SCD) with involvement of the posterior columns in the cervical and thoracic cord is a common presentation of this disorder. In this case report, we describe a 43 year old woman with pernicious anemia and myelopathy with atypical clinical features. The patient presented with motor symptoms, a sensory level and bladder dysfunction. She had severe autonomic disturbances including an episode of unexplained bronchospasm, which has not been previously reported as a manifestation of vitamin B12 deficiency. We review the literature regarding these rarely reported features of vitamin B12 deficiency, and discuss aspects of management of this reversible condition. We emphasize the importance of awareness of autonomic disturbances in B12 deficient individuals. PMID:19720386

Puntambekar, Preeti; Basha, Maysaa M; Zak, Imad T; Madhavan, Ramesh

2009-12-15

99

Folate and vitamin B12 status of adolescent girls in northern Nigeria.  

PubMed Central

The diets of populations in many developing countries are low in folate and vitamin B12 and a deficiency of either of these vitamins results in increased risk for cardiovascular disease and neural tube defects. The rates of neural tube defects in Nigeria are among the highest reported worldwide. Since many girls marry at an early age in northern Nigeria, we therefore determined the folate and vitamin B12 status of adolescent girls between 12 and 16 years of age in Maiduguri, Nigeria. The mean serum folate concentration for subjects was 15.3 +/- 5.2 nmol/L. Whereas only four subjects (2.4%) had serum folate concentrations lower than 6.8 nmol/L, a level indicative of negative folate balance, 9% of the subjects had serum vitamin B12 concentrations at or below 134 pmol/L, the lower limit of the reference range for their age group. Serum homocysteine was measured in 56 of the 162 subjects and the mean level was 15.9 +/- 5.0 mumol/L. The majority of subjects had serum homocysteine concentrations above the upper limit of the reference range for their age group. We conclude that the adolescent girls we studied were at greater risk for vitamin B12 deficiency than folate deficiency. This conclusion is consistent with the fact that their diet included few foods that contained vitamin B12. PMID:10946529

VanderJagt, D. J.; Spelman, K.; Ambe, J.; Datta, P.; Blackwell, W.; Crossey, M.; Glew, R. H.

2000-01-01

100

TENEUR EN VITAMINE B12 DU FOIE ET DU CONTENU DE L'INTESTIN  

E-print Network

V. - TENEUR EN VITAMINE B12 DU FOIE ET DU CONTENU DE L'INTESTIN R. F�VRIER, J. P. VACHEL M. MICHEL relations encore mal connues entre l'action des antibiotiques et le métabolisme de la vitamine Bi2. Pour obtenir des informations plus complètes sur ce point, nous avons effectué des dosages de vitamine Bi2 sur

Boyer, Edmond

101

[Surface-enhanced raman spectroscopy study of vitamin B12 on copper electrode].  

PubMed

The vitamin B12 molecule has long fascinated chemists because of its exclusive complex structure and unusual reactivities in biological systems. In order to achieve a better understanding of the structural attribute of the Vitamin B12 molecule when it interacted with metal, in the present paper, the vitamin B12 molecules adsorbed on variation of copper electrode potential from 0 to -1.0 V was studied by surface-enhanced Raman spectroscopy (SERS). An excellent SERS substrate was obtained with insitu electrochemical oxidation-reduction cycle (ORC), and its surface roughness was characterized by atomic force microscope (AFM). Assignments of Raman peaks observed by normal Raman spectrum (NRS) and SERS spectra of vitamin B12 molecule were given based on previous literatures. It was found that the potential-dependent relative intensity changed in SERS spectra which depended on the vitamin B12 molecular orientation with respect to the copper surface according to the surface selection rule (SSR). It was concluded that the corrin ring was adsorbed in tilt form on copper surface and the Co-CN group was farther away from the copper surface at higher potentials. With the decrease in potential, the tilt angle between the corrin ring and copper surface became smaller, then the Co-N group and 5,6 dimethylbenzimidazole group got close to the copper surface. The results offered an important structural attribute of vitamin B12 molecule when it interacted with copper electrode for the first time, and supplied a meaningful reference for the electrochemical bioactivity of the vitamin B12 molecule. PMID:24369644

Wang, Bo; Chang, Da-hu; Lu, Gang; Wang, Tian-hu; Zhang, Zhen-long; Mo, Yu-jun

2013-09-01

102

Are vitamin B12 and folate deficiency clinically important after roux-en-Y gastric bypass?  

PubMed

Although iron, vitamin B12, and folate deficiency have been well documented after gastric bypass operations performed for morbid obesity, there is surprisingly little information on either the natural course or the treatment of these deficiencies in Roux-en-Y gastric bypass (RYGB) patients. During a 10-year period, a complete blood count and serum levels of iron, total iron-binding capacity, vitamin B12, and folate were obtained in 348 patients preoperatively and postoperatively at 6-month intervals for the first 2 years, then annually thereafter. The principal objectives of this study were to determine how readily patients who developed metabolic deficiencies after Roux-en-Y gastric bypass responded to postoperative supplements of the deficient micronutrient and to learn whether the risk of developing these deficiencies decreases over time. Hemoglobin and hematocrit levels were significantly decreased at all postoperative intervals in comparison to preoperative values. Moreover, at each successive interval through 5 years, hemoglobin and hematocrit were decreased significantly compared to the preceding interval. Folate levels were significantly increased compared to preoperative levels at all time intervals. Iron and vitamin B12 levels were lower than preoperative measurements and remained relatively stable postoperatively. Half of the low hemoglobin levels were not associated with iron deficiency. Taking multivitamin supplements resulted in a lower incidence of folate deficiency but did not prevent iron or vitamin B12 deficiency. Oral supplementation of iron and vitamin B12 corrected deficiencies in 43% and 81% of cases, respectively. Folate deficiency was almost always corrected with multivitamins alone. No patient had symptoms that could be attributed to either vitamin B12 or folate deficiency Conversely, many patients had symptoms of iron deficiency and anemia. Lack of symptoms of vitamin B12 and folate deficiency suggests that these deficiencies are not clinically important after RYGB. Conversely, iron deficiency and anemia are potentially serious problems after RYGB, particularly in younger women. Hence we recommend prophylactic oral iron supplements to premenopausal women who undergo RYGB. PMID:9843603

Brolin, R E; Gorman, J H; Gorman, R C; Petschenik, A J; Bradley, L J; Kenler, H A; Cody, R P

1998-01-01

103

Review of the magnitude of folate and vitamin B12 deficiencies worldwide.  

PubMed

Human deficiencies of folate and vitamin B12 result in adverse effects which may be of public health significance, but the magnitude of these deficiencies is unknown. Therefore, we examine the prevalence data currently available, assess global coverage of surveys, determine the frequency with which vitamin status assessment methods are used, and identify patterns of status related to geographical distribution and human development. Surveys were identified through PubMed and the Vitamin and Mineral Nutrition Information System at the World Health Organization (WHO). Since different thresholds were frequently used to define deficiency, measures of central tendency were used to compare blood vitamin concentrations among countries. The percentage of countries with at least one survey is highest in the WHO Regions of South-East Asia and Europe. Folate and vitamin B12 status were most frequently assessed in women of reproductive age (34 countries), and in all adults (27 countries), respectively. Folate status assessment surveys assessed plasma or serum concentrations (55%), erythrocyte folate concentrations (21%), or both (23%). Homocysteine was assessed in one-third of the surveys of folate and vitamin B12 status (31% and 34% respectively), while methylmalonic acid was assessed in fewer surveys of vitamin B12 status (13%). No relationship between vitamin concentrations and geographical distribution, level of development, or population groups could be identified, but nationally representative data were few. More representative data and more consistent use of thresholds to define deficiency are needed in order to assess whether folate and vitamin B12 deficiencies are a public health problem. PMID:18709880

McLean, Erin; de Benoist, Bruno; Allen, Lindsay H

2008-06-01

104

Characterisation of vitamin B12 immunoaffinity columns and method development for determination of vitamin B12 in a range of foods, juices and pharmaceutical products using immunoaffinity clean-up and high performance liquid chromatography with UV detection  

Microsoft Academic Search

New rapid and simpler procedures, using immunoaffinity columns, have been developed for the determination of vitamin B12 in a range of samples including three different US National Institute of Standard and Technology (NIST) Reference Materials, infant formula, powdered energy drinks and bars, wheat breakfast cereal, carbonated soft drinks, fruit juices and vitamin B12 tablets. The procedures involved extraction of vitamin

E. C. Marley; E. Mackay; G. Young

2009-01-01

105

Revisiting Metformin: Annual Vitamin B12 Supplementation may become Mandatory with Long-Term Metformin Use.  

PubMed

Monitoring of adverse drug reactions of a drug is a continuous process and runs through-out the life of a drug. Many rare adverse effects of a drug are documented after years of use; when a single case (signal generation) is reported leading subsequently to reporting of more cases. Deficiency of Vitamin B12 (vit B(12)) is a known sequel of prolonged metformin therapy. It was recommended to have annual measurement of serum vit B(12) levels in patients on long term metformin therapy way back in 1970 itself. After more than 50 years of use of metformin, we have come to know that metformin induced vit B(12) deficiency can cause neuropathy; forcing to change the recommendation from annual screening of vit B(12) levels to annual supplementation of vit B(12). PMID:21264109

Mahajan, R; Gupta, K

2010-10-01

106

Folate and vitamin B-12 biomarkers in NHANES: history of their measurement and use12345  

PubMed Central

NHANES measured folate and vitamin B-12 status biomarkers, starting with serum folate from NHANES I (1974–1975) through 2010. Subsequent NHANES measured additional biomarkers [eg, red blood cell folate, serum vitamin B-12, total homocysteine (tHcy), methylmalonic acid, serum folic acid, and 5-methyltetrahydrofolic acid]. Examples of the uses of these data are wide ranging and include public policy applications, the derivation of reference intervals, and research. Periodically, the National Center for Health Statistics and its federal partners convene expert panels to review the use of the folate- and vitamin B-12–related biomarkers in NHANES. These panels have evaluated the need for results to be comparable across time and with published data and the use of crossover studies and adjustment equations to ensure comparability. With the recent availability of reference methods and materials for serum folate and tHcy, NHANES has started to use traceability approaches to enhance the accuracy and comparability of its results. A major user concern over the years has been the use of cutoffs to estimate the prevalence of inadequate folate and vitamin B-12 status. Because these cutoffs depend on the measurement procedure, several expert panels suggested approaches for dealing with cutoff challenges. This review summarizes the history and use of folate- and vitamin B-12–related biomarkers beginning with NHANES I (1974–1975) through 2010. PMID:21593508

Johnson, Clifford L

2011-01-01

107

Low serum vitamin B12 levels in an outpatient HIV-infected population.  

PubMed

A retrospective review was conducted on serum vitamin B12 levels in an HIV-infected outpatient cohort, many of whom received antiretroviral therapy. B12 levels were obtained at most staging visits (every six months) and when clinically indicated. For each serum B12 level, laboratory values and clinical symptoms were recorded. Thirty-two patients (32/251 or 13%) had at least one low B12 level (<211pg/mL) during the course of their HIV infection. Within two years of their initial HIV presentation, 6/57 patients had a low serum B12. Using multiple linear regression analysis, a higher serum B12 level was significantly associated with higher folate levels, African-American race, and lower mean corpuscular volume. B12 levels increased significantly after initiating antiretroviral therapy (416 vs 535 pg/mL, P=0.04). In conclusion, low serum B12 levels occur commonly among HIV-infected patients, even at early stages without overt symptoms of B12 deficiency. Antiretroviral therapy may increase serum B12 levels. PMID:15006076

Hepburn, Matthew J; Dyal, Kamal; Runser, Lloyd A; Barfield, Russell L; Hepburn, Lisa M; Fraser, Susan L

2004-02-01

108

Carbon nanotube-chitosan modified disposable pencil graphite electrode for vitamin B12 analysis.  

PubMed

A single walled carbon nanotube-chitosan (SWCNT-chitosan) modified disposable pencil graphite electrode (PGE) was used in this study for the electrochemical detection of Vitamin B(12). Electrochemical behaviors of SWCNT-chitosan PGE and chitosan modified PGE were compared by using cyclic voltammetry (CV), square-wave voltammetry (SWV) and electrochemical impedance spectroscopy (EIS) techniques. SWCNT-chitosan modified electrode was also used for the quantification of Vitamin B(12) in pharmaceutical products. The results show that this electrode system is suitable for sensitive Vitamin B(12) analysis giving good recovery results. The surface morphologies of the SWCNT-chitosan PGE, chitosan modified PGE and unmodified PGE were characterized by using scanning electron microscopy (SEM). PMID:21616649

Kuralay, Filiz; Vural, Tayfun; Bayram, Cem; Denkbas, Emir Baki; Abaci, Serdar

2011-10-01

109

Discoveries of vitamin B12 and selenium enzymes.  

PubMed

My undergraduate education at Cornell University was followed by graduate studies on methane fermentations under the guidance of H.A. Barker at the University of California, Berkeley. My Ph.D. degree was granted in June 1949. Two anaerobic microorganisms isolated from the mud flats of San Francisco Bay served as sources of biochemical research material for later studies at the National Institutes of Health in Bethesda. These organisms, Methanococcus vannielii and Clostridium sticklandii, proved to be especially rich sources of selenium-dependent enzymes and seleno-tRNAs. New B12 coenzyme-dependent enzymes that catalyzed intermediate steps in the anaerobic conversion of lysine to fatty acids and ammonia were isolated from C. sticklandii and characterized. My research efforts since 1970 have dealt primarily with various aspects of selenium biochemistry. We have shown that selenium is an essential constituent of several enzymes in prokaryotes. Se is present in these either as a selenocysteine residue in the protein or alternatively, in a few molybdoenzymes, as a component of a bound cofactor. Recent studies with a human adenocarcinoma cell line led to the unexpected discovery that selenocysteine occurs in mammalian thioredoxin reductase. The selenium located in a redox center of this enzyme is essential for catalytic activity. PMID:12045088

Stadtman, Thressa Campbell

2002-01-01

110

Decreased vitamin B12 availability induces ER stress through impaired SIRT1-deacetylation of HSF1  

PubMed Central

Vitamin B12 (cobalamin) is a key determinant of S-adenosyl methionine (SAM)-dependent epigenomic cellular regulations related to methylation/acetylation and its deficiency produces neurodegenerative disorders by elusive mechanisms. Sirtuin 1 deacetylase (SIRT1) triggers cell response to nutritional stress through endoplasmic reticulum (ER) stress. Recently, we have established a N1E115 dopaminergic cell model by stable expression of a transcobalamin–oleosin chimera (TO), which impairs cellular availability of vitamin B12, decreases methionine synthase activity and SAM level, and reduces cell proliferation. In contrast, oleosin-transcobalamin chimera (OT) does not modify the phenotype of transfected cells. Presently, the impaired cellular availability of vitamin B12 in TO cells activated irreversible ER stress pathways, with increased P-eIF-2?, P-PERK, P-IRE1?, ATF6, ATF4, decreased chaperon proteins and increased pro-apoptotic markers, CHOP and cleaved caspase 3, through reduced SIRT1 expression and consequently greater acetylation of heat-shock factor protein 1 (HSF1). Adding either B12, SIRT1, or HSF1 activators as well as overexpressing SIRT1 or HSF1 dramatically reduced the activation of ER stress pathways in TO cells. Conversely, impairing SIRT1 and HSF1 by siRNA, expressing a dominant negative form of HSF1, or adding a SIRT1 inhibitor led to B12-dependent ER stress in OT cells. Addition of B12 abolished the activation of stress transducers and apoptosis, and increased the expression of protein chaperons in OT cells subjected to thapsigargin, a strong ER stress stimulator. AdoX, an inhibitor of methyltransferase activities, produced similar effects than decreased B12 availability on SIRT1 and ER stress by a mechanism related to increased expression of hypermethylated in cancer 1 (HIC1). Taken together, these data show that cellular vitamin B12 has a strong modulating influence on ER stress in N1E115 dopaminergic cells. The impaired cellular availability in vitamin B12 induces irreversible ER stress by greater acetylation of HSF1 through decreased SIRT1 expression, whereas adding vitamin B12 produces protective effects in cells subjected to ER stress stimulation. PMID:23519122

Ghemrawi, R; Pooya, S; Lorentz, S; Gauchotte, G; Arnold, C; Gueant, J-L; Battaglia-Hsu, S-F

2013-01-01

111

Low serum vitamin B12 levels among psychiatric patients admitted in Butabika mental hospital in Uganda  

PubMed Central

Background Psychiatric manifestations have been noted in patients with low serum vitamin B12 levels even in the absence of other neurologic and/or haematologic abnormalities. There is no literature on low serum B12 prevalence among Ugandans with psychiatric illnesses. The aim of this study was to establish the prevalence, risk factors, and clinical manifestations of low serum vitamin B12 among psychiatric patients admitted in a Mental Health Hospital in Uganda. Method Using a cross sectional descriptive study design, 280 in-patients selected by systematic sampling were studied using a standardized protocol. Low serum vitamin B12 was defined as a level?B12 in 28.6% of the participants. Absent vibration sense which was significantly associated (58.3% Vs. 26.7%: OR?=?3.84 (95% C.I. 1.18, 12.49); p-value?=?0.025) with low vitamin B12 was observed among 12 participants. Macro-ovalocytes present among 23 participants on peripheral film were significantly associated with low serum levels (73.9% Vs. 26.2%: OR?=?7.99 (95% C.I. 3.01, 21.19) p-value?B12 levels included psychiatric diagnosis of schizophrenia (AOR 1.74 (95% C.I. 1.00, 3.02); p-value?=?0.049), duration of psychiatric illness?>?or?=?3 years (AOR 2.27 (95% C.I. 1.29, 3.98); p-value?=?0.004), and hospitalization?B12 is common among hospitalized psychiatric patients with the majority having no haematological findings. Associated risk factors included having a psychiatric diagnosis of schizophrenia, a shorter duration of hospitalization and longer duration of psychiatric illness. Female participants were less likely to have low serum vitamin B12 levels. Routine screening for serum vitamin B12 levels should be adopted by all hospitals for admitted psychiatric patients. PMID:24533701

2014-01-01

112

Utilization of dietary protein in the vitamin B12-deficient rats.  

PubMed

Utilization of dietary protein in vitamin B12 (B12)-deficient rats was evaluated by determinating the content of plasma protein, urinary excretion of nitrogen compounds, and nitrogen-balance after the rats were fed on a B12-deficient soy bean protein diet by pair-feeding for 100 days. The severe B12-deficiency was confirmed in rats by a remarkable increase in urinary methylmalonic acid excretion and a remarkable decrease in the hepatic B12 level. Growth of B12-deficient rats was significantly retarded as compared both with ad libitum-feeding control rats and pair-feeding control rats. The growth retardation due to B12-deficiency was alleviated by the administration of 1 microgram/day of CN-B12 for 30 days. Plasma total protein and albumin levels in rats fed on a B12-deficient diet decreased, compared with those in pair-feeding control, and increase in urea-nitrogen was observed. The excretion of urinary nitrogen compounds, such as urea-nitrogen, allantoin, and creatinine, was significantly depressed by B12-deficiency compared with those in pair-feeding control. The administration of CN-B12 to B12-deficient rats for 30 days resulted in the recovery of the changes in plasma proteins and urinary excretion of nitrogen compounds. The above results suggested that the extreme B12-deficiency depressed the utilization of dietary protein in rats. Moreover, the decrease in urinary urea-nitrogen excretion was supposed to be due to the adaptation by the depression of the dietary protein utilization. PMID:8789621

Kawata, T; Tashiro, A; Tamiki, A; Suga, K; Kamioka, S; Yamada, K; Wada, M; Tadokoro, T; Maekawa, A

1995-01-01

113

HPLC-ESI-MS analysis of Vitamin B 12 in food products and in multivitamins-multimineral tablets  

Microsoft Academic Search

Methods for the determination of Vitamin B12 remain limited due to their low sensitivity and poor selectivity. In the present work, a simple and sensitive HPLC-ESI-MS method for determining Vitamin B12 in food products and in multivitamin-multimineral tablets was developed. Vitamin B12 was extracted from food products with 50mM sodium acetate buffer (pH 4.0) in the presence of sodium cyanide.

Xubiao Luo; Bo Chen; Li Ding; Fei Tang; Shouzhuo Yao

2006-01-01

114

Low Vitamin B12 Levels among Newly-Arrived Refugees from Bhutan, Iran and Afghanistan: A Multicentre Australian Study  

PubMed Central

Background Vitamin B12 deficiency is prevalent in many countries of origin of refugees. Using a threshold of 5% above which a prevalence of low Vitamin B12 is indicative of a population health problem, we hypothesised that Vitamin B12 deficiency exceeds this threshold among newly-arrived refugees resettling in Australia, and is higher among women due to their increased risk of food insecurity. This paper reports Vitamin B12 levels in a large cohort of newly arrived refugees in five Australian states and territories. Methods In a cross-sectional descriptive study, we collected Vitamin B12, folate and haematological indices on all refugees (n?=?916; response rate 94% of eligible population) who had been in Australia for less than one year, and attended one of the collaborating health services between July 2010 and July 2011. Results 16.5% of participants had Vitamin B12 deficiency (<150 pmol/L). One-third of participants from Iran and Bhutan, and one-quarter of participants from Afghanistan had Vitamin B12 deficiency. Contrary to our hypothesis, low Vitamin B12 levels were more prevalent in males than females. A higher prevalence of low Vitamin B12 was also reported in older age groups in some countries. The sensitivity of macrocytosis in detecting Vitamin B12 deficiency was only 4.6%. Conclusion Vitamin B12 deficiency is an important population health issue in newly-arrived refugees from many countries. All newly-arrived refugees should be tested for Vitamin B12 deficiency. Ongoing research should investigate causes, treatment, and ways to mitigate food insecurity, and the contribution of such measures to enhancing the health of the refugee communities. PMID:23469126

Benson, Jill; Phillips, Christine; Kay, Margaret; Webber, Murray T.; Ratcliff, Alison J.; Correa-Velez, Ignacio; Lorimer, Michelle F.

2013-01-01

115

An appraisal of the value of vitamin B12 in the prevention of motion sickness  

NASA Technical Reports Server (NTRS)

It has been suggested that vitamin B12 given by intramuscular injection can significantly reduce the occurrence of motion sickness in susceptible individuals (Banks, 1980). Since it is known that B12 influences the metabolism of histidine and choline, dietary precursors to neurotransmitters with established roles in motion sickness, an experimental evaluation has been undertaken of the efficacy of B12 in the prevention of motion sickness induced by controlled coriolis simulation. Subjects executed standardized head movements at successively higher rpm until a malaise III endpoint was reached. Following two baseline tests with this motion stressor, subjects received a B12 injection, a second injection two weeks later, and a final motion sickness test three weeks later. No significant differences in the susceptibility to motion sickness were noted after B12.

Kohl, R. L.; Lacey, C. L.; Homick, J. L.

1983-01-01

116

Beyond catalysis: vitamin B12 as a cofactor in gene regulation.  

PubMed

Vitamin B12 is well known as an enzyme cofactor in the catalysis of many important biological reactions, and the role of B12 in regulation of bacterial gene expression as a ligand of riboswitches is well established. Only recently evidence has emerged that B12 can also affect bacterial gene expression by acting as a cofactor of regulatory proteins. In 2011 a role of B12 as a cofactor of the transcriptional repressor of carotenogenesis, CarH, in Myxococcus xanthus was reported. B12 is required for light-dependent DNA binding by CarH, which can therefore be considered to be a new type of photoreceptor. Cheng et al. (2014) report the identification of B12 as a cofactor of the AerR protein in Rhodobacter capsulatus. AerR acts as an antirepressor of the CrtJ protein, which represses photosynthesis genes when binding to its target promoters. As in Myxococcus B12 may have the role of a chromophore in photoreception, but it is suggested that a main function of AerR is the sensing of B12. The co-regulation of the pathways is beneficial because the syntheses of B12 , haem and bacteriochlorophylls share common precursors and the accumulation of the free molecules is toxic. PMID:24330414

Klug, Gabriele

2014-02-01

117

Biomarkers of Folate and Vitamin B12 Are Related in Blood and Cerebrospinal Fluid  

Microsoft Academic Search

Background: B-vitamins (folate, B12) are important mi- cronutrients for brain function and essential cofactors for homocysteine (HCY) metabolism. Increased HCY has been related to neurological and psychiatric disor- ders. We studied the role of the B-vitamins in HCY metabolism in the brain. Methods: We studied blood and cerebrospinal fluid (CSF) samples from 72 patients who underwent lumbar puncture. We measured

Rima Obeid; Panagiotis Kostopoulos; Jean-Pierre Knapp; Mariz Kasoha; George Becker; Klaus Fassbender; Wolfgang Herrmann

118

Methionine, folic acid, vitamin B b12 sand unidentified factors in the nutrition of the growing chick  

E-print Network

to determine the vitamin B12 ~ biotin, pantothenic acid and folic acid content of same. The microbiolcgical assay procedure of Skegg et al. (1". 50) wi. th ~~~ ~~~ ~ (A. T. C. C. ) as the test organism was used to determine the vitamin B12 content... to determine the vitamin B12 ~ biotin, pantothenic acid and folic acid content of same. The microbiolcgical assay procedure of Skegg et al. (1". 50) wi. th ~~~ ~~~ ~ (A. T. C. C. ) as the test organism was used to determine the vitamin B12 content...

Welch, Billy E

2012-06-07

119

Folate and Vitamin B12 Related Genes and Risk for Omphalocele  

PubMed Central

Both taking folic acid-containing vitamins around conception and consuming food fortified with folic acid have been reported to reduce omphalocele rates. Genetic factors are etiologically important in omphalocele as well; our pilot study showed a relationship with the folate metabolic enzyme gene methylenetetrahydrofolate reductase (MTHFR). We studied 169 non-aneuploid omphalocele cases and 761 unaffected, matched controls from all New York State births occurring between 1998 and 2005 to look for associations with single nucleotide polymorphisms (SNPs) known to be important in folate, vitamin B12, or choline metabolism. In the total study population, variants in the transcobalamin receptor gene (TCblR), rs2232775 (Q8R), and the MTHFR gene, rs1801131 (1298A>C), were significantly associated with omphalocele. In African-Americans significant associations were found with SNPs in genes for the vitamin B12 transporter (TCN2) and the vitamin B12 receptor (TCblR). A SNP in the homocysteine-related gene, betaine-homocysteine S-methyltransferase (BHMT), rs3733890 (R239Q), was significantly associated with omphalocele in both African-Americans and Asians. Only the TCblR association in the total population remained statistically significant if Bonferroni correction was applied. The finding that transcobalamin receptor (TCblR) and transporter (TCN2) SNPs and a BHMT SNP were associated with omphalocele suggests that disruption of methylation reactions, in which folate, vitamin B12, and homocysteine play critical parts, may be a risk factor for omphalocele. Our data, if confirmed, suggest that supplements containing both folic acid and vitamin B12 may be beneficial in preventing omphaloceles. PMID:22116453

Mills, James L.; Carter, Tonia C.; Kay, Denise M.; Browne, Marilyn; Brody, Lawrence C.; Liu, Aiyi; Romitti, Paul A.; Caggana, Michele; Druschel, Charlotte

2012-01-01

120

DNA methylation and subclinical vitamin deficiency of folate, pyridoxal-phosphate and vitamin B12 in chronic alcoholics  

Microsoft Academic Search

Alcohol abuse is known to adversely affect folate, vitamin B12 and pyridoxal-phosphate metabolism, which are required for de novo synthesis of methionine. Methionine is the precursor of S-adenosylmethionine, the principal methylating agent in the organism, including DNA. The objective of this study was to measure DNA methylation in peripheral lymphocytes and the circulating concentrations of these three vitamins in chronic

M. Cravo; L. Glória; M. E. Camilo; M. Resende; J. Neves Cardoso; C. Nobre Leitão; F. Costa Mira

1997-01-01

121

Influence of Meal on Plasma Folate and Vitamin B12, by Three Methods - and on Vitamin B6, Homocysteine and Red Blood Cell Folate  

Microsoft Academic Search

Vitamins are brought by meals. Some of them are cofactors in homocysteine metabolism, and, if plasma homo- cysteine values are not known to have a circadian rhythm, little is known about meal influence on blood folate, and vitamins B12 and B6. The aim of this study is to analyze the effect of breakfast and lunch on plasma folate, vitamins B12

Mirande Candito; Bakhouche Houcher; François Roux; Genevieve Potier de Courcy; Anne Caramella; Frederick Berthier; Abdelhamid Aberkane

2005-01-01

122

Copper control of bacterial nitrous oxide emission and its impact on vitamin B12-dependent metabolism.  

PubMed

Global agricultural emissions of the greenhouse gas nitrous oxide (N2O) have increased by around 20% over the last 100 y, but regulation of these emissions and their impact on bacterial cellular metabolism are poorly understood. Denitrifying bacteria convert nitrate in soils to inert di-nitrogen gas (N2) via N2O and the biochemistry of this process has been studied extensively in Paracoccus denitrificans. Here we demonstrate that expression of the gene encoding the nitrous oxide reductase (NosZ), which converts N2O to N2, is regulated in response to the extracellular copper concentration. We show that elevated levels of N2O released as a consequence of decreased cellular NosZ activity lead to the bacterium switching from vitamin B12-dependent to vitamin B12-independent biosynthetic pathways, through the transcriptional modulation of genes controlled by vitamin B12 riboswitches. This inhibitory effect of N2O can be rescued by addition of exogenous vitamin B12. PMID:24248380

Sullivan, Matthew J; Gates, Andrew J; Appia-Ayme, Corinne; Rowley, Gary; Richardson, David J

2013-12-01

123

The effects of 'supra-physiological' vitamin B12 administration on temporary threshold shift.  

PubMed

The aim of this study was to evaluate, in 20 young volunteer subjects, the effects of supra-physiological vitamin B12 administration on noise-induced temporary threshold shift (TTS). All subjects had hearing thresholds within 15 dBHL and type A tympanograms. The subjects were randomly assigned to two different groups. Experimental group subjects received cyanocobalamin, 1 mg daily for 7 days, and 5 mg on the eighth day. Control group subjects received a placebo injection daily for 8 days. The vitamin B12 concentration, hearing thresholds and TTS2 (10 min of exposure, narrowband noise centred at 3 kHz, bandwidth of 775 Hz, 112 dBSPL) were measured before and 8 days after treatment. At the end of treatment, the serum vitamin B12 concentration was significantly increased in the experimental group. After 8 days of treatment, the control group showed the same hearing thresholds and TTS2 degrees. Statistical analysis showed that TTS2 decreased significantly at 3 and 4kHz when cobalamin was used to increase the serum concentration of vitamin B12 to > 2350 pg/ml. In addition, a protective effect at 3 kHz in the experimental group was evident when compared with the placebo group. These results suggest that elevated plasma cyanocobalamin levels may reduce the risk of hearing dysfunction resulting from noise exposure in healthy, young subjects. PMID:15198380

Quaranta, Antonio; Scaringi, Angelo; Bartoli, Roberto; Margarito, Maria Angela; Quaranta, Nicola

2004-03-01

124

Rapid microbiological assay of serum vitamin B12 by electronic counter  

Microsoft Academic Search

A new method of measuring the growth of Lactobacillus leichmannii is reported. Its adoption for the estimation of serum vitamin B12 levels shortens the incubation period required to five hours at 45°C. The method is compared statistically with a standard method of estimation, requiring incubation at 37°C., by duplicate determinations on 106 hospital patients. The significance of the apparently decreased

J. Stuart; S. A. Sklaroff

1966-01-01

125

Are We Missing Vitamin B 12 Deficiency in the Primary Care Setting?  

Microsoft Academic Search

Vitamin B12 deficiency is present in 5% to 20% of the elderly population and may begin in middle age, although there is a paucity of research to demonstrate this suspicion. One common cause, malabsorption, is affected by many factors often seen in the primary care setting, including prolonged use of proton pump inhibitors or metformin or as a result of

Rebecca Hilgen Bryan

2010-01-01

126

Brief Report: Childhood Disintegrative Disorder as a Likely Manifestation of Vitamin B12 Deficiency  

ERIC Educational Resources Information Center

Childhood disintegrative disorder is a rare disorder, characterized by regression of acquired skills after a period of normal development. The case of childhood disintegrative disorder presented here was found to have vitamin B12 deficiency and hyperhomocysteinemia on extensive evaluation to find a probable cause for regression. This case…

Malhotra, Savita; Subodh, B. N.; Parakh, Preeti; Lahariya, Sanjay

2013-01-01

127

Cobalamin (vitamin B 12) in subacute combined degeneration and beyond: traditional interpretations and novel theories  

Microsoft Academic Search

Subacute combined degeneration (SCD) is a neuropathy due to cobalamin (Cbl) (vitamin B12) deficiency acquired in adult age. Hitherto, the theories advanced to explain the pathogenesis of SCD have postulated a causal relationship between SCD lesions and the impairment of either or both of two Cbl-dependent reactions. We have identified a new experimental model, the totally gastrectomized rat, to reproduce

Giuseppe Scalabrino

2005-01-01

128

Some histological manifestations in the vitamin B b 12 sdeficient newborn rat  

E-print Network

. The results of the present experiment further support the ides that vitamin Bl2 plays a role in fst metabolism, Lipotropio activity, as reported in a vitamin B 12 deficiency in the newborn rat and in ths chick embryo~ may be similar to that lipo tropic...- xyribonucleic acid or of angrloid acoumulation 4, The exact nature of the role played by vitamin H12 in ths animal cell is not known, However, the results of this experiment seem to indicate that an effective approach to ths problem could be made by more...

Jones, Carroll Christian

2012-06-07

129

Combined dietary folate, vitamin B-12, and vitamin B-6 intake influences plasma docosahexaenoic acid concentration in rats  

PubMed Central

Background Folate, vitamin B-12, and vitamin B-6 are essential nutritional components in one-carbon metabolism and are required for methylation capacity. The availability of these vitamins may therefore modify methylation of phosphatidylethanolamine (PE) to phosphatidylcholine (PC) by PE-N-methyltransferase (PEMT) in the liver. It has been suggested that PC synthesis by PEMT plays an important role in the transport of polyunsaturated fatty acids (PUFAs) like docosahexaenoic acid (DHA) from the liver to plasma and possibly other tissues. We hypothesized that if B-vitamin supplementation enhances PEMT activity, then supplementation could also increase the concentration of plasma levels of PUFAs such as DHA. To test this hypothesis, we determined the effect of varying the combined dietary intake of these three B-vitamins on plasma DHA concentration in rats. Methods In a first experiment, plasma DHA and plasma homocysteine concentrations were measured in rats that had consumed a B-vitamin-poor diet for 4?weeks after which they were either continued on the B-vitamin-poor diet or switched to a B-vitamin-enriched diet for another 4?weeks. In a second experiment, plasma DHA and plasma homocysteine concentrations were measured in rats after feeding them one of four diets with varying levels of B-vitamins for 4?weeks. The diets provided 0% (poor), 100% (normal), 400% (enriched), and 1600% (high) of the laboratory rodent requirements for each of the three B-vitamins. Results Plasma DHA concentration was higher in rats fed the B-vitamin-enriched diet than in rats that were continued on the B-vitamin-poor diet (P?=?0.005; experiment A). Varying dietary B-vitamin intake from deficient to supra-physiologic resulted in a non-linear dose-dependent trend for increasing plasma DHA (P?=?0.027; experiment B). Plasma DHA was lowest in rats consuming the B-vitamin-poor diet (P?>?0.05 vs. normal, P?vitamin-high diet (P??0.05 vs. enriched). B-vitamin deficiency significantly increased plasma total homocysteine but increasing intake above normal did not significantly reduce it. Nevertheless, in both experiments plasma DHA was inversely correlated with plasma total homocysteine. Conclusion These data demonstrate that dietary folate, vitamin B-12, and vitamin B-6 intake can influence plasma concentration of DHA. PMID:22647268

2012-01-01

130

[Encephalomyelopathy due to vitamin B12 deficiency with seizures as a predominant symptom].  

PubMed

We report a 39-year-old man who developed seizures as a predominant symptom of vitamin B12 deficiency. About a month before admission to our hospital, he experienced flickering vision, and had generalized convulsive seizures about ten times a day. On admission, he presented with visual disturbance and paralysis of the left leg. Brain MRI revealed a tumor-like lesion in the medial side of the right frontal lobe. Follow-up MRI about 2 weeks after admission demonstrated multiple lesions in the periaqueduct, the medial side of the bilateral thalami, the bilateral frontal lobes, and the bilateral occipital lobes. After administration of antiepileptic drugs, his condition was well-controlled. Paralysis of his left leg was gradually improved, and abnormal findings on brain MRI disappeared except that in the right frontal lobe cortex, which was considered to be cortical laminar necrosis. 123I-IMP-SPECT showed hyperperfusion in the bilateral occipital lobes. About 3 months after the first admission, he was readmitted because of ataxic gait and numbness in the extremities. Laboratory tests revealed macrocytic anemia and vitamin B12 deficiency. Spinal MRI revealed typical findings of subacute combined degeneration. Brain MRI showed multiple new lesions in the bilateral dorsal sides of the medulla, cerebellar hemispheres, interthalamic adhesion, and left frontal cortex. After the initiation of vitamin B12 supplementary therapy, the symptoms were improved, and the abnormal MRI findings disappeared. Serum anti-gastric-parietal-cell antibody and anti-intrinsic-factor antibody were positive. 123I-IMP-SPECT demonstrated hypoperfusion in the bilateral occipital lobes, possibly reflecting visual disturbance. To the best of our knowledge, this is the first report indicating that vitamin B12 deficiency may insult various brain regions as well as the spinal cord with reversibility. Vitamin B12 deficiency should be also considered in the differential diagnosis of the causes of epilepsy. PMID:19462816

Matsumoto, Arifumi; Shiga, Yusei; Shimizu, Hiroshi; Kimura, Itaru; Hisanaga, Kinya

2009-04-01

131

How Nature Builds the Pigments of Life: The Conquest of Vitamin B12  

NASA Astrophysics Data System (ADS)

In part because humans cannot synthesize vitamin B12 and must obtain it from organisms that produce it and because B12 deficiency leads to pernicious anemia, it has been important to understand how microorganisms build this quite complex substance. As shown here, an interdisciplinary attack was needed, which combined the strengths of genetics, molecular biology, enzymology, chemistry, and spectroscopy. This allowed the step-by-step synthetic pathway of B12 to be elucidated, and this approach has acted as a model for future research on the synthesis of substances in living organisms. One practical outcome of such an approach has been the improved availability of B12 for animal feedstuffs and human health.

Battersby, Alan R.

1994-06-01

132

J. LENOIR. -NOTE SUR LA DGRADATION From the results obtained after the sur vey of vitamin B12  

E-print Network

of vitamin B12 content during the fabrication and ripening of kefir, the following conclusions can be drawn : The fabrication and ripening of Kefir involve some losses in vitamin B12. In the product being made with milk in which Kefir fungi have been added, such losses reached an average proportion of 22,09 per cent after

Paris-Sud XI, Université de

133

Dietary pectin shortens the biologic half-life of vitamin B-12 in rats by increasing fecal and urinary losses  

SciTech Connect

As little as 5% of pectin added to a fiber-free diet elevates urinary methylmalonic acid (MMA) severalfold in vitamin B-12--deprived rats. The present study examines whether increased urinary MMA reflects lower vitamin B-12 status or occurs only because of fermentation of pectin by intestinal bacteria and increased production of propionate, a precursor of MMA. By monitoring urinary and fecal excretion of {sup 57}Co after a tracer dose of ({sup 57}Co)vitamin B-12, we found the biologic half-life of vitamin B-12 to be 59 d for rats fed a fiber-free diet and only 19 d for rats fed a 5% pectin diet. Also, pectin-fed rats oxidized only 12% of a 1-mmol dose of ({sup 14}C)propionate to {sup 14}CO{sub 2} in 2 h, whereas rats fed the fiber-free diet expired 33% of the dose. Finally, high urinary MMA persisted even after the removal of pectin from the diet. We conclude that dietary pectin accelerates vitamin B-12 depletion in rats, possibly by interfering with enterohepatic recycling of vitamin B-12. By stimulating microbial propionate production, pectin and other fermentable fibers may also contribute to increased urinary MMA in vitamin B-12 deficiency, but a larger propionate pool does not account for the other effects of pectin on vitamin B-12 status.

Cullen, R.W.; Oace, S.M. (Univ. of California, Berkeley (USA))

1989-08-01

134

Vitamin B12 deficiency in Caenorhabditis elegans results in loss of fertility, extended life cycle, and reduced lifespan.  

PubMed

Vitamin B12 (B12) deficiency has been linked to developmental disorders, metabolic abnormalities, and neuropathy; however, the mechanisms involved remain poorly understood. Caenorhabditis elegans grown under B12-deficient conditions for five generations develop severe B12 deficiency associated with various phenotypes that include decreased egg-laying capacity (infertility), prolonged life cycle (growth retardation), and reduced lifespan. These phenotypes resemble the consequences of B12 deficiency in mammals, and can be induced in C. elegans in only 15 days. Thus, C. elegans is a suitable animal model for studying the biological processes induced by vitamin deficiency. PMID:23772381

Bito, Tomohiro; Matsunaga, Yohei; Yabuta, Yukinori; Kawano, Tsuyoshi; Watanabe, Fumio

2013-01-01

135

Vitamin B12-dependent taurine synthesis regulates growth and bone mass  

PubMed Central

Both maternal and offspring-derived factors contribute to lifelong growth and bone mass accrual, although the specific role of maternal deficiencies in the growth and bone mass of offspring is poorly understood. In the present study, we have shown that vitamin B12 (B12) deficiency in a murine genetic model results in severe postweaning growth retardation and osteoporosis, and the severity and time of onset of this phenotype in the offspring depends on the maternal genotype. Using integrated physiological and metabolomic analysis, we determined that B12 deficiency in the offspring decreases liver taurine production and associates with abrogation of a growth hormone/insulin-like growth factor 1 (GH/IGF1) axis. Taurine increased GH-dependent IGF1 synthesis in the liver, which subsequently enhanced osteoblast function, and in B12-deficient offspring, oral administration of taurine rescued their growth retardation and osteoporosis phenotypes. These results identify B12 as an essential vitamin that positively regulates postweaning growth and bone formation through taurine synthesis and suggests potential therapies to increase bone mass. PMID:24911144

Roman-Garcia, Pablo; Quiros-Gonzalez, Isabel; Mottram, Lynda; Lieben, Liesbet; Sharan, Kunal; Wangwiwatsin, Arporn; Tubio, Jose; Lewis, Kirsty; Wilkinson, Debbie; Santhanam, Balaji; Sarper, Nazan; Clare, Simon; Vassiliou, George S.; Velagapudi, Vidya R.; Dougan, Gordon; Yadav, Vijay K.

2014-01-01

136

Geographical gradients of dissolved Vitamin B12 in the Mediterranean Sea  

PubMed Central

Most eukaryotic phytoplankton require vitamin B12 to grow. However, the cycling of this organic growth factor has received substantially less attention than other bioactive substances such as trace metals in the marine environment. This is especially true in the Mediterranean Sea, where direct measurements of dissolved vitamins have never been reported. We report here the first direct measurements of dissolved vitamin B12 across longitudinal gradients in Mediterranean waters. The range of vitamin B12 concentrations measured over the whole transect was 0.5–6.2 pM, which is slightly higher than the range (undetectable—4 pM) of ambient concentrations measured in other open ocean basins in the Pacific and Atlantic oceans. The concentrations measured in the western basin were significantly higher (p < 0.05) than those of the eastern basin. They were positively correlated with chlorophyll concentrations in the most western part of the basin, and did not show any significant correlation with any other biological variables in other regions of the sampling transect. PMID:23772225

Bonnet, S.; Tovar-Sanchez, A.; Panzeca, C.; Duarte, C. M.; Ortega-Retuerta, E.; Sanudo-Wilhelmy, S. A.

2013-01-01

137

Characterisation of vitamin B12 immunoaffinity columns and method development for determination of vitamin B12 in a range of foods, juices and pharmaceutical products using immunoaffinity clean-up and high performance liquid chromatography with UV detection.  

PubMed

New rapid and simpler procedures, using immunoaffinity columns, have been developed for the determination of vitamin B12 in a range of samples including three different US National Institute of Standard and Technology (NIST) Reference Materials, infant formula, powdered energy drinks and bars, wheat breakfast cereal, carbonated soft drinks, fruit juices and vitamin B12 tablets. The procedures involved extraction of vitamin B12 using water or sodium acetate buffer and enzyme digestion (using pepsin or alpha-amylase, or both) if necessary. The extract was clarified and passed through "EASI-EXTRACT Vitamin B12", an immunoaffinity column containing monoclonal antibody with high affinity and specificity to vitamin B12. Subsequently, the vitamin B12 immunoaffinity column was washed with 10 ml water and the vitamin B12 was released from the column with 3 ml methanol. Following evaporation, the samples were reconstituted in mobile phase and analysed by HPLC-UV at 361 nm on an ACE 3AQ analytical column using a gradient elution consisting of 0.025% trifluoroacetic acid in water and acetonitrile. Analysis of three types of NIST Standard Reference Materials in triplicate demonstrated the results of the immunoaffinity column method were comparable to microbiological assay results. Method repeatability was determined for all samples analysed and ranged between 0.8 and 10%, demonstrating the method was repeatable with complex matrices (NIST 2383) containing low levels of vitamin B12 (0.44 microg per 100 g), as well as simpler matrices, such as vitamin tablets containing high levels (2000 microg per 0.849 g) of vitamin B12. PMID:19680900

Marley, E C; Mackay, E; Young, G

2009-03-01

138

Polymorphisms within the vitamin B 12 dependent methylmalonyl-coA mutase are not risk factors for neural tube defects  

Microsoft Academic Search

Methionine synthase and methylmalonyl-CoA mutase (mutase) are the only two known vitamin B12 (B12) dependent enzymes in humans. A lower level of B12 has been shown to be an independent maternal risk factor for neural tube defects (NTDs) prompting an investigation of common genetic variants within B12 dependent enzymes. To investigate the role of methylmalonyl-CoA mutase variants we studied 279

Anne Parle-McDermott; Edward J McManus; James L Mills; Valerie B O’Leary; Faith Pangilinan; Christopher Cox; Andrea Weiler; Anne M Molloy; Mary Conley; Deborah Watson; John M Scott; Lawrence C Brody; Peadar N Kirke

2003-01-01

139

Development of a two-step cultivation strategy for the production of vitamin B12 by Bacillus megaterium  

PubMed Central

Background Vitamin B12 is a fascinating molecule which acts as a co-factor in the metabolism of many organisms, especially affecting DNA synthesis and regulation, fatty acid synthesis and energy production. The synthesis of vitamin B12 is limited to a few of bacteria and archaea. Therefore, industrial microbial fermentation is used to meet annual demands worldwide of vitamin B12 and as an alternative method to the chemical synthesis which requires at least 60 steps that is uneconomical. Bacillus megaterium is one of vitamin B12 producers and an ideal host for many biotechnology applications and being one of the best tools for the industrial production of several enzymes. Therefore, a two-step optimization strategy was established to produce high yield of vitamin B12 by B. megaterium through the provision of the production requirements and the suitable conditions for the biosynthesis of vitamin B12. Results We achieved the optimum conditions for the fermentation process of B. megaterium to produce high yield of vitamin B12 in a practical way based on statistical design and analysis which allowed vitamin B12 production to increase up to 759-fold (204.46 ?g/l) as compared with control without parameters (0.26 ?g/L). High performance liquid chromatography coupled to variable wavelength detector and mass spectrometry has been used to identify vitamin B12 forms and confirm the results. Conclusions We developed the fermentation process of B. megaterium to enhance the production of vitamin B12 by providing the required supplements for the synthesis of vitamin B12 (CoCl2, ?-aminolevulinic acid (ALA) and 5,6-dimethylbenzimidazole (DMB)) and dividing the fermentation process into three stages. In addition, the optimum incubation times of the three fermentation stages were investigated and performed with reducing number of experimental and evaluated multiple parameters and their interactions by using statistical experimental design and analysis. All of these strategies has proven successful in enhancing the production of vitamin B12 up to 204.46 ?g/l and demonstrated that B. megaterium could be a good candidate for the industrial production of vitamin B12. PMID:25023574

2014-01-01

140

Vitamin B12 injections: considerable source of work for the district nurse.  

PubMed Central

Between June and September 1984, district nurses who worked in Coventry were asked to submit returns giving details of the patients for whom they administered vitamin B12 injections. Of 492 patients identified, 382 (78%) were receiving injections more frequently than the recommended three monthly dose of hydroxy-cobalamin. An extra 3751 injections are being administered a year. Four hundred and thirty (88%) of these patients have conditions for which the drug is of proven benefit, so the increased frequency of injections accounts for most of the observed excess. A total of 2000 hours a year of district nurse time is spent with these patients. The nursing service is under increasing strain. Changes in vitamin B12 prescribing alone could make between 600 and 1470 hours available for other patient needs. PMID:3921179

Middleton, J; Wells, W

1985-01-01

141

Folate and vitamin B12 status of women in Newfoundland at their first prenatal visit  

PubMed Central

BACKGROUND: Newfoundland has one of the highest rates of neural tube defects in North America. Given the association between low maternal folic acid levels and neural tube defects, a cross-sectional study was conducted to obtain base-line data on the folate and vitamin B12 status of a sample of women in Newfoundland who were pregnant. METHODS: Blood samples were collected between August 1996 and July 1997 from 1424 pregnant women in Newfoundland during the first prenatal visit (at approximately 16 weeks' gestation); this represented approximately 25% of the women in Newfoundland who were pregnant during this period. The samples were analysed for serum folate, vitamin B12, red blood cell folate and homocysteine. RESULTS: Median values for serum folate, red blood cell folate and serum vitamin B12 were 25 nmol/L, 650 nmol/L and 180 pmol/L, respectively. On the basis of the interpretive criteria used for red blood cell folate status, 157 (11.0%) of the 1424 women were deficient (< 340 nmol/L) and a further 180 (12.6%) were classified as indeterminate (340-420 nmol/L). Serum homocysteine levels, measured in subsets of the red blood cell folate status groups, supported the inadequate folate status. Serum vitamin B12 levels of 621 (43.6%) women were classified as deficient or marginal; however, the validity of the interpretive criteria for pregnant women is questionable. INTERPRETATION: A large proportion of pregnant women surveyed in Newfoundland in 1997 had low red blood cell folate levels. PMID:10862228

House, J D; March, S B; Ratnam, S; Ives, E; Brosnan, J T; Friel, J K

2000-01-01

142

Dual pathology as a result of spinal stenosis and vitamin B12 deficiency  

Microsoft Academic Search

Vitamin B12 deficiency can confound the clinical assessment of patients presenting with features of spinal disorders. Speciality\\u000a practice within spinal surgery may lead the clinician to a focus upon spinal explanations for symptoms and that belief may\\u000a be reinforced by supporting imaging. In the presence of mainly sensory symptoms consideration and exclusion of non surgical\\u000a causes needs to occur. This

Mohammed Shakil Patel; Zurqa Rasul; Philip Sell

143

Vitamin B12 status of patients treated with metformin: a cross-sectional cohort study  

Microsoft Academic Search

AimTo assess the vitamin B12 status of patients with type 2diabetes who had been receiving metformin treatment for at least one year.MethodsPatients with type 2 diabetes attending a diabetes clinic were included in a cross-sectional cohort study. Patients exposed to metformin for more than one year (n=53) were compared with a non-exposed control group (n=31). Serum cobalamin and other variables

Leif Sparre Hermann; BO Nilsson; Staffan Wettre

2004-01-01

144

Folate, vitamin B12 and total homocysteine levels in neonates from Brazil  

Microsoft Academic Search

Objective:To determine folates, vitamin B12 and total homocysteine levels among neonates from mothers of low or high socioeconomic status.Design:We carried out a cross-sectional transversal study comprising 143 neonates from two maternity hospitals in the city of Salvador, Northeast of Brazil. Cord blood samples were obtained at the time of delivery from newborns from low (group 1, n=77) or high (group

F D Couto; L M O Moreira; D B dos Santos; M G Reis; M S Gonçalves

2007-01-01

145

Dietary Intake of Vitamin B12 and Folic Acid Is Associated With Lower Blood Pressure in Japanese Preschool Children  

Microsoft Academic Search

BackgroundAn elevated plasma homocysteine level is an independent risk factor for high blood pressure and cardiovascular disease, and its level is regulated by three vitamins; vitamin B6, B12, and folic acid. Until now, the association between the intake of these vitamins and blood pressure has been examined only in adult populations. We purposed to examine the association between dietary intake

Yuya Tamai; Keiko Wada; Michiko Tsuji; Kozue Nakamura; Yukari Sahashi; Kaori Watanabe; Keiko Yamamoto; Kyoko Ando; Chisato Nagata

2011-01-01

146

Methylcobalamin - A form of vitamin B12 identified and characterised in Chlorella vulgaris.  

PubMed

Vitamin B12 is among the most essential biomolecules required for crucial metabolic processes in humans. Vitamin B12 was extracted from Chlorella vulgaris biomass under aqueous conditions, partially purified by passing the extract through amberlite XAD-2, Sep-Pak columns, and further purified by HPLC. The target peak eluent was subjected to characterisation by tandem mass spectrometry (MS/MS), selected ion recording (SIR) and multiple reaction monitoring (MRM) and identified as methylcobalamin (Me-Cbl). Quantification of Me-Cbl was carried out by microbiological and chemiluminescence methods, and found to be 29.87±2?g/100g and 26.84±2?g/100g dry weight, respectively. The presence of Me-Cbl was further substantiated using gold nanoparticle (AuNPs) based aptamer analysis, and found to be 28.02±2?g/100g dry weight. Good similarity was observed among all the methods. Methylcobalamin, a form of vitamin B12 was identified in C. vulgaris and this finding enhances its use as a nutritional supplement. PMID:25306351

Kumudha, Anantharajappa; Selvakumar, Sagaya; Dilshad, Pullancheri; Vaidyanathan, Gopal; Thakur, Munna Singh; Sarada, Ravi

2015-03-01

147

Disposable pencil graphite electrode modified with peptide nanotubes for Vitamin B12 analysis  

NASA Astrophysics Data System (ADS)

In this study, peptide nanostructures from diphenylalanine were synthesized in various solvents with various polarities and characterized with Scanning Electron Microscopy (SEM) and Powder X-ray Diffraction (PXRD) techniques. Formation of peptide nanofibrils, nanovesicles, nanoribbons, and nanotubes was observed in different solvent mediums. In order to investigate the effects of peptide nanotubes (PNT) on electrochemical behavior of disposable pencil graphite electrodes (PGE), electrode surfaces were modified with fabricated peptide nanotubes. Electrochemical activity of the pencil graphite electrode was increased with the deposition of PNTs on the surface. The effects of the solvent type, the peptide nanotube concentration, and the passive adsorption time of peptide nanotubes on pencil graphite electrode were studied. For further electrochemical studies, electrodes were modified for 30 min by immobilizing PNTs, which were prepared in water at 6 mg/mL concentration. Vitamin B12 analyses were performed by the Square Wave (SW) voltammetry method using modified PGEs. The obtained data showed linearity over the range of 0.2 ?M and 9.50 ?M Vitamin B12 concentration with high sensitivity. Results showed that PNT modified PGEs were highly simple, fast, cost effective, and feasible for the electro-analytical determination of Vitamin B12 in real samples.

Pala, Betül Bozdo?an; Vural, Tayfun; Kuralay, Filiz; Ç?rak, Tamer; Bolat, Gülçin; Abac?, Serdar; Denkba?, Emir Baki

2014-06-01

148

The effect of cobalt supplementation on the immune response in vitamin B12 deficient Texel lambs.  

PubMed

The effect of cobalt supplementation on the immune reactivity in vitamin B12 deficient lambs was measured by comparing the humoral and cell-mediated immune responses against bovine herpes virus type 1 and Mycobacterium paratuberculosis. In addition, faecal egg counts were performed after natural infection with gastrointestinal nematodes. The experiments were performed with registered Texel twin lambs of the same sex. One lamb of each twin received three cobalt pellets divided over the grazing period. The non-supplemented lambs had lower serum vitamin B12 levels than their supplemented brother or sister. Our results demonstrate significantly lower lymphoblastic responses against Mycobacterium paratuberculosis in non-supplemented lambs compared with supplemented lambs 4 weeks after paratuberculosis vaccination. Vitamin B12 deficient lambs in this study had significant higher faecal egg counts than their supplemented brother or sister after natural infection with gastrointestinal nematodes. No differences were found in total and differential white blood cell counts, in total protein, albumin, alpha-, beta- and gamma-globulin and in antibody production against bovine herpes virus type 1 and Mycobacterium paratuberculosis. PMID:9014314

Vellema, P; Rutten, V P; Hoek, A; Moll, L; Wentink, G H

1996-12-01

149

Vitamin B12 and Folic Acid Imbalance Modifies NK Cytotoxicity, Lymphocytes B and Lymphoprolipheration in Aged Rats  

PubMed Central

Different vitamin B12 and folic acid concentrations could exacerbate the immune response. The aim was to evaluate different dietary folic acid and vitamin B12 levels on the immune response in aged rats. Male Sprague Dawley aged rats were assigned to three folic acid groups (deficient, control, supplemented) each in absence of vitamin B12 for 30 days. Several parameters of innate and acquired immune responses were measured. Serum and hepatic folate levels increased according to folic acid dietary level, while vitamin B12 levels decreased. There was a significant decrease in natural killer cell-mediated cytotoxicity in the spleen for the vitamin B12 deficient diet and folic acid control diet groups. Significant changes in CD45 lymphocyte subsets were also observed according to dietary imbalance. Lymphoproliferative response to concanavalin A and phytohemagglutinin did not differ significantly between groups. The spleen response to lipopolysaccharide increased significantly, but was unmodified for the other organs. An imbalance between dietary vitamin B12 and folic acid concentrations alters some immunological parameters in aged rats. Therefore, the ratio between folate and vitamin B12 could be as important as their absolute dietary concentrations. PMID:24288024

Partearroyo, Teresa; Ubeda, Natalia; Montero, Ana; Achon, Maria; Varela-Moreiras, Gregorio

2013-01-01

150

Effect of vitamin B12 on functional recovery and histopathologic changes of tibial nerve-crushed rats.  

PubMed

Recent studies have suggested a neuroprotective effect for vitamin B12. The present study investigated the effects of vitamin B12, diclofenac and celecoxib in separate and combined treatments on functional recovery of crushed tibial nerve in rats. In ketamine plus xylazin anesthetized rats, right tibial nerve was crushed using a small hemoatatic forceps. Footprints were recorded 1 day before and on days 7, 14 and 21 after induction of nerve injury. Tibial functional index (TFI) was used to evaluate the recovery of tibial nerve function. Histological changes of tibial nerve were investigated by light microscopy. The recovery of TFI values were significantly accelerated with 10 consecutive days treatments with 0.1 and 0.5?mg/kg of vitamin B12, 5?mg/kg of diclofenac and 1 and 5?mg/kg of celecoxib. The severity of Wallerian degeneration was reduced by above-mentioned doses of vitamin B12, diclofenac and celecoxib. Documented effects were observed when 0.1?mg/kg of vitamin B12 was concurrently used with 1?mg/kg of diclofenac and or 0.2?mg/kg of celecoxib. In the present study, vitamin B12, celecoxib and diclofenac (at a high dose) showed neuroprotective effects. Inhibition of cyclooxygenase (COX) 1 and 2 pathways may be involved in neuroprotective effect of vitamin B12. PMID:24470311

Tamaddonfard, E; Farshid, A A; Samadi, F; Eghdami, K

2014-09-01

151

Recreational Nitrous Oxide Abuse-Induced Vitamin B12 Deficiency in a Patient Presenting with Hyperpigmentation of the Skin  

PubMed Central

Vitamin B12 deficiency causes skin hyperpigmentation, subacute combined degeneration of the spinal cord, and megaloblastic anemia. Although vitamin B12 deficiency rarely occurs in well-nourished, healthy, young people, nitrous oxide (N2O) intoxication is an important cause of vitamin B12 deficiency in this cohort. N2O, a colorless gas used as an anesthetic since the late 19th century because of its euphoric and analgesic qualities, is now used as a recreational drug and is available via the Internet and at clubs. Here, we describe the case of a 29-year-old woman presenting with skin hyperpigmentation as her only initial symptom after N2O abuse for approximately 2 years. N2O intoxication-induced vitamin B12 deficiency was diagnosed based on the skin pigmentation that had manifested over the dorsa of her fingers, toes, and trunk, coupled with myeloneuropathy of the posterior and lateral columns, a low serum vitamin B12 level, an elevated serum homocysteine level, and the N2O exposure revealed while establishing the patient's history. Symptoms improved significantly with vitamin B12 treatment. We recommend that dermatologists consider N2O intoxication-induced vitamin B12 deficiency as a potential cause of skin hyperpigmentation and myeloneuropathy of the posterior and lateral columns in young, otherwise healthy patients. Failure to recognize this presentation may result in inappropriate treatment, thus affecting patients’ clinical outcomes. PMID:23898268

Chiang, Tsung-Ta; Hung, Chih-Tsung; Wang, Wei-Ming; Lee, Jiunn-Tay; Yang, Fu-Chi

2013-01-01

152

Dipstick based immunochemiluminescence biosensor for the analysis of vitamin B12 in energy drinks: a novel approach.  

PubMed

In this article, we describe a dipstick based immunochemiluminescence (immuno-CL) biosensor for the detection of vitamin B(12) in energy drinks. The method is a direct competitive type format involving the immobilization of vitamin B(12) antibody on nitrocellulose membrane (NC) followed by treatment with vitamin B(12) and vitamin B(12)-alkaline phosphatase conjugate to facilitate the competitive binding. The dipstick was further treated with substrate disodium 2-chloro-5-(4-methoxyspiro {1,2-dioxetane-3,2¢-(5¢-chloro)tricyclo[3.3.1.13,7]decan}-4-yl)-1-phenyl phosphate (CDP-Star) to generate chemiluminescence (CL). The number of photons generated was inversely proportional to the vitamin B(12) concentration. After systematic optimization, the limit of detection was 1 ng mL(-1). The coefficient of variation was below 0.2% for both intra- and inter-assay precision. Vitamin B(12) was extracted from energy drinks with recovery ranged from 90 to 99.4%. Two different energy drinks samples were analyzed, and a good correlation was observed when the data were compared with a reference enzyme linked immuno sorbent assay (ELISA) method. The developed method is suitable for an accurate, sensitive, and high-throughput screening of vitamin B(12) in energy drinks samples. The dipstick technique based on immuno-CL is suitable for the detection of several analyte in food and environmental samples. PMID:22444541

Selvakumar, L S; Thakur, M S

2012-04-13

153

Recreational nitrous oxide abuse-induced vitamin B12 deficiency in a patient presenting with hyperpigmentation of the skin.  

PubMed

Vitamin B12 deficiency causes skin hyperpigmentation, subacute combined degeneration of the spinal cord, and megaloblastic anemia. Although vitamin B12 deficiency rarely occurs in well-nourished, healthy, young people, nitrous oxide (N2O) intoxication is an important cause of vitamin B12 deficiency in this cohort. N2O, a colorless gas used as an anesthetic since the late 19th century because of its euphoric and analgesic qualities, is now used as a recreational drug and is available via the Internet and at clubs. Here, we describe the case of a 29-year-old woman presenting with skin hyperpigmentation as her only initial symptom after N2O abuse for approximately 2 years. N2O intoxication-induced vitamin B12 deficiency was diagnosed based on the skin pigmentation that had manifested over the dorsa of her fingers, toes, and trunk, coupled with myeloneuropathy of the posterior and lateral columns, a low serum vitamin B12 level, an elevated serum homocysteine level, and the N2O exposure revealed while establishing the patient's history. Symptoms improved significantly with vitamin B12 treatment. We recommend that dermatologists consider N2O intoxication-induced vitamin B12 deficiency as a potential cause of skin hyperpigmentation and myeloneuropathy of the posterior and lateral columns in young, otherwise healthy patients. Failure to recognize this presentation may result in inappropriate treatment, thus affecting patients' clinical outcomes. PMID:23898268

Chiang, Tsung-Ta; Hung, Chih-Tsung; Wang, Wei-Ming; Lee, Jiunn-Tay; Yang, Fu-Chi

2013-05-01

154

The Conformational Coupling and Translocation Mechanism of Vitamin B12 ATP-Binding Cassette Transporter BtuCD  

PubMed Central

ATP-binding cassette transporter BtuCD mediating vitamin B12 uptake in Escherichia coli couples the energy of ATP hydrolysis to the translocation of vitamin B12 across the membrane into the cell. Elastic normal mode analysis of BtuCD demonstrates that the simultaneous substrate trapping at periplasmic cavity and ATP binding at the ATP-binding cassette (BtuD) dimer proceeds readily along the lowest energy pathway. The transport power stroke is attributed to ATP-hydrolysis-induced opening of the nucleotide-binding domain dimer, which is coupled to conformational rearrangement of transmembrane domain (BtuC) helices leading to the closing at the periplasmic side and opening at the cytoplasmic gate. Simultaneous hydrolysis of two ATP is supported by the fact that antisymmetric movement of BtuD dimer implying alternating hydrolysis cannot induce effective conformational change of the translocation pathway. A plausible mechanism of translocation cycle is proposed in which the possible effect of the association of periplasmic binding protein BtuF to the transporter is also considered. PMID:17951296

Weng, Jingwei; Ma, Jianpeng; Fan, Kangnian; Wang, Wenning

2008-01-01

155

Adverse effect of metformin therapy on serum vitamin B12 and folate: short-term treatment causes disadvantages?  

PubMed

Diabetes is a global public health challenge that imposes heavy burdens on communities and individuals. Metformin, the first-line medication for diabetes, has the superiority of reducing risk of macrovascular diseases, all-cause mortality and even possibly cancers. Recent observational studies, however, have demonstrated that long-term metformin therapy increases the probability of vitamin B12 and folate deficiency, and might contribute to the progression of diabetic peripheral neuropathy. Despite metformin is widely used and extensively studied, randomized controlled trials performed to explore the effects of metformin on vitamin B12 and folate are limited. Besides, whether short-term treatment causes vitamin deficiency is a pending issue. We postulate that even a few-month treatment with metformin results in the decrease of vitamin B12 and folate. However, supplementation of vitamin B12 rather than the combination of vitamin B12 and folate might be profitable based on the mechanism of metformin on vitamins in patients with type 2 diabetes. This viewpoint differs from those of majority that a combined supplementation of vitamin B12 and folate is inclined to be advised. PMID:23751310

Xu, Lijuan; Huang, Zhimin; He, Xiaoying; Wan, Xuesi; Fang, Donghong; Li, Yanbing

2013-08-01

156

Influence du cobalt et de la vitamine B12 sur la croissance et la survie des cilis du rumen in vitro,  

E-print Network

Influence du cobalt et de la vitamine B12 sur la croissance et la survie des ciliés du rumen, 94010 Créteil. Summary. lnfluence of cobalt and vitamin B12 on growth and survival of rumen ciliates of vitamin B12 was studied on the growth of rumen ciliates in the presence of normal bacterial population

Boyer, Edmond

157

Vitamin B12 extensive thoracic myelopathy: clinical, radiological and prognostic aspects. Two cases report and literature review.  

PubMed

The myelopathy caused by vitamin B12 deficiency is known as subacute combined degeneration. It is rare, but a well known cause of demyelination of the dorsal columns of the spinal cord. The magnetic resonance imaging is characterized by an increased signal on T2-weighted images involving the posterior columns of cervical and thoracic cord. There have been few cases in literature with extensive lesions (more than seven levels) of the thoracic spinal cord. The clinical and radiological improvements are possible if the replacement of vitamin B12 is initiated precocious. We present two rare cases of extensive thoracic myelopathy due to vitamin B12 deficiency. The first is a young woman with complete clinical recovery and important radiologic improvement after early treatment. In addition, the second case is an older man with partial response to the treatment. Those cases illustrate the importance of considering vitamin B12 deficiency in any patient, who presents with myelopathy. PMID:23468407

de Medeiros, Frederico Carvalho; de Albuquerque, Lucas Alverne Freitas; de Souza, Renata Brant; Gomes Neto, Antonio Pereira; Christo, Paulo Pereira

2013-10-01

158

Genetic architecture of vitamin B12 and folate levels uncovered applying deeply sequenced large datasets.  

PubMed

Genome-wide association studies have mainly relied on common HapMap sequence variations. Recently, sequencing approaches have allowed analysis of low frequency and rare variants in conjunction with common variants, thereby improving the search for functional variants and thus the understanding of the underlying biology of human traits and diseases. Here, we used a large Icelandic whole genome sequence dataset combined with Danish exome sequence data to gain insight into the genetic architecture of serum levels of vitamin B(12) (B12) and folate. Up to 22.9 million sequence variants were analyzed in combined samples of 45,576 and 37,341 individuals with serum B(12) and folate measurements, respectively. We found six novel loci associating with serum B(12) (CD320, TCN2, ABCD4, MMAA, MMACHC) or folate levels (FOLR3) and confirmed seven loci for these traits (TCN1, FUT6, FUT2, CUBN, CLYBL, MUT, MTHFR). Conditional analyses established that four loci contain additional independent signals. Interestingly, 13 of the 18 identified variants were coding and 11 of the 13 target genes have known functions related to B(12) and folate pathways. Contrary to epidemiological studies we did not find consistent association of the variants with cardiovascular diseases, cancers or Alzheimer's disease although some variants demonstrated pleiotropic effects. Although to some degree impeded by low statistical power for some of these conditions, these data suggest that sequence variants that contribute to the population diversity in serum B(12) or folate levels do not modify the risk of developing these conditions. Yet, the study demonstrates the value of combining whole genome and exome sequencing approaches to ascertain the genetic and molecular architectures underlying quantitative trait associations. PMID:23754956

Grarup, Niels; Sulem, Patrick; Sandholt, Camilla H; Thorleifsson, Gudmar; Ahluwalia, Tarunveer S; Steinthorsdottir, Valgerdur; Bjarnason, Helgi; Gudbjartsson, Daniel F; Magnusson, Olafur T; Sparsø, Thomas; Albrechtsen, Anders; Kong, Augustine; Masson, Gisli; Tian, Geng; Cao, Hongzhi; Nie, Chao; Kristiansen, Karsten; Husemoen, Lise Lotte; Thuesen, Betina; Li, Yingrui; Nielsen, Rasmus; Linneberg, Allan; Olafsson, Isleifur; Eyjolfsson, Gudmundur I; Jørgensen, Torben; Wang, Jun; Hansen, Torben; Thorsteinsdottir, Unnur; Stefánsson, Kari; Pedersen, Oluf

2013-06-01

159

Genetic Architecture of Vitamin B12 and Folate Levels Uncovered Applying Deeply Sequenced Large Datasets  

PubMed Central

Genome-wide association studies have mainly relied on common HapMap sequence variations. Recently, sequencing approaches have allowed analysis of low frequency and rare variants in conjunction with common variants, thereby improving the search for functional variants and thus the understanding of the underlying biology of human traits and diseases. Here, we used a large Icelandic whole genome sequence dataset combined with Danish exome sequence data to gain insight into the genetic architecture of serum levels of vitamin B12 (B12) and folate. Up to 22.9 million sequence variants were analyzed in combined samples of 45,576 and 37,341 individuals with serum B12 and folate measurements, respectively. We found six novel loci associating with serum B12 (CD320, TCN2, ABCD4, MMAA, MMACHC) or folate levels (FOLR3) and confirmed seven loci for these traits (TCN1, FUT6, FUT2, CUBN, CLYBL, MUT, MTHFR). Conditional analyses established that four loci contain additional independent signals. Interestingly, 13 of the 18 identified variants were coding and 11 of the 13 target genes have known functions related to B12 and folate pathways. Contrary to epidemiological studies we did not find consistent association of the variants with cardiovascular diseases, cancers or Alzheimer's disease although some variants demonstrated pleiotropic effects. Although to some degree impeded by low statistical power for some of these conditions, these data suggest that sequence variants that contribute to the population diversity in serum B12 or folate levels do not modify the risk of developing these conditions. Yet, the study demonstrates the value of combining whole genome and exome sequencing approaches to ascertain the genetic and molecular architectures underlying quantitative trait associations. PMID:23754956

Thorleifsson, Gudmar; Ahluwalia, Tarunveer S.; Steinthorsdottir, Valgerdur; Bjarnason, Helgi; Gudbjartsson, Daniel F.; Magnusson, Olafur T.; Spars?, Thomas; Albrechtsen, Anders; Kong, Augustine; Masson, Gisli; Tian, Geng; Cao, Hongzhi; Nie, Chao; Kristiansen, Karsten; Husemoen, Lise Lotte; Thuesen, Betina; Li, Yingrui; Nielsen, Rasmus; Linneberg, Allan; Olafsson, Isleifur; Eyjolfsson, Gudmundur I.; J?rgensen, Torben; Wang, Jun; Hansen, Torben; Thorsteinsdottir, Unnur; Stefansson, Kari; Pedersen, Oluf

2013-01-01

160

Vitamin B12-responsive severe leukoencephalopathy and autonomic dysfunction in a patient with "normal" serum B12 levels.  

PubMed

Leukoencephalopathy and autonomic dysfunction have been described in individuals with very low serum B(12) levels (<200 pg/ml), in addition to psychiatric changes, neuropathy, dementia and subacute combined degeneration. Elevated homocysteine and methylmalonic acid levels are considered more sensitive and specific for evaluating truly functional B(12) deficiency. A previously healthy 62-year-old woman developed depression and cognitive deficits with autonomic dysfunction that progressed over the course of 5 years. The patient had progressive, severe leukoencephalopathy on multiple MRI scans over 5 years. Serum B(12) levels ranged from 267 to 447 pg/ml. Homocysteine and methylmalonic acid levels were normal. Testing for antibody to intrinsic factor was positive, consistent with pernicious anaemia. After treatment with intramuscular B(12) injections (1000 ?g daily for 1 week, weekly for 6 weeks, then monthly), she made a remarkable clinical recovery but remained amnesic for major events of the last 5 years. Repeat MRI showed partial resolution of white matter changes. Serum B(12), homocysteine and methylmalonic acid levels are unreliable predictors of B(12)-responsive neurologic disorders, and should be thoroughly investigated and presumptively treated in patients with unexplained leukoencephalopathy because even long-standing deficits may be reversible. PMID:20587489

Graber, J J; Sherman, F T; Kaufmann, H; Kolodny, E H; Sathe, S

2010-12-01

161

Retention of vitamin B 12 during manufacture of six fermented dairy products using a validated radio protein-binding assay  

Microsoft Academic Search

The aim of this work was to study vitamin B12 retention during manufacture of six fermented dairy products. Careful validation of a commercial radio protein-binding kit showed this assay to be suitable after optimisation of sample pre-treatment and control of the kit for possible matrix effects. In fermented milks, vitamin B12 concentrations decreased by 40–60%, compared with the starting milk,

Karin Arkbåge; Cornelia Witthöft; Rangne Fondén; Margaretha Jägerstad

2003-01-01

162

Discovery of Novel Sources of Vitamin B12 in Traditional Korean Foods from Nutritional Surveys of Centenarians  

PubMed Central

Human longevity can be explained by a variety of factors, among them, nutritional factor would play an important role. In our study of Korean centenarians for their longevity, the apparent nutritional imbalance in the traditional semi-vegetarian diet raised a special attention, especially on vitamin B12 status, supplied by animal foods. Interestingly, we found that the prevalence of vitamin B12 deficient Korean centenarians was not higher compared with those from Western nations with animal-oriented traditional foods. We assumed that there might be some unveiled sources for vitamin B12 in the Korean traditional foods. Screening of vitamin B12 contents has revealed that some traditional soybean-fermented foods, such as Doenjang and Chunggukjang, and seaweeds contain considerable amounts of vitamin B12. Taken together, it can be summarized that the traditional foods, especially of fermentation, might be evaluated for compensation of the nutritional imbalance in the vegetable-oriented dietary pattern by supplying vitamin B12, resulting in maintenance of health status. PMID:21436999

Kwak, Chung Shil; Lee, Mee Sook; Oh, Se In; Park, Sang Chul

2010-01-01

163

Micronutrient status in female university students: iron, zinc, copper, selenium, vitamin B12 and folate.  

PubMed

Young women are at an increased risk of micronutrient deficiencies, particularly due to higher micronutrient requirements during childbearing years and multiple food group avoidances. The objective of this study was to investigate biomarkers of particular micronutrients in apparently healthy young women. Female students (n = 308; age range 18-35 year; Body Mass Index 21.5 ± 2.8 kg/m2; mean ± SD) were recruited to participate in a cross-sectional study. Blood samples were obtained from participants in the fasted state and analysed for biomarkers of iron status, vitamin B12, folate, homocysteine, selenium, zinc, and copper. The results show iron deficiency anaemia, unspecified anaemia, and hypoferritinemia in 3%, 7% and 33.9% of participants, respectively. Low vitamin B12 concentrations (<120 pmol/L) were found in 11.3% of participants, while 4.7% showed sub-clinical deficiency based on serum methylmalonic acid concentrations >0.34 ?mol/L. Folate concentrations below the reference range were observed in 1.7% (serum) or 1% (erythrocytes) of participants, and 99.7% of the participant had erythrocyte-folate concentrations >300 nmol/L. Serum zinc concentrations <10.7 ?mol/L were observed in 2% of participants. Serum copper and selenium concentrations were below the reference range in 23% and 11% of participants, respectively. Micronutrient deficiencies including iron and vitamin B12, and apparent excess of folate are present in educated Australian female students of childbearing age, including those studying nutrition. The effects of dietary behaviours and food choices on markers of micronutrient status require further investigation. PMID:25401503

Fayet-Moore, Flavia; Petocz, Peter; Samman, Samir

2014-01-01

164

Micronutrient Status in Female University Students: Iron, Zinc, Copper, Selenium, Vitamin B12 and Folate  

PubMed Central

Young women are at an increased risk of micronutrient deficiencies, particularly due to higher micronutrient requirements during childbearing years and multiple food group avoidances. The objective of this study was to investigate biomarkers of particular micronutrients in apparently healthy young women. Female students (n = 308; age range 18–35 year; Body Mass Index 21.5 ± 2.8 kg/m2; mean ± SD) were recruited to participate in a cross-sectional study. Blood samples were obtained from participants in the fasted state and analysed for biomarkers of iron status, vitamin B12, folate, homocysteine, selenium, zinc, and copper. The results show iron deficiency anaemia, unspecified anaemia, and hypoferritinemia in 3%, 7% and 33.9% of participants, respectively. Low vitamin B12 concentrations (<120 pmol/L) were found in 11.3% of participants, while 4.7% showed sub-clinical deficiency based on serum methylmalonic acid concentrations >0.34 ?mol/L. Folate concentrations below the reference range were observed in 1.7% (serum) or 1% (erythrocytes) of participants, and 99.7% of the participant had erythrocyte-folate concentrations >300 nmol/L. Serum zinc concentrations <10.7 ?mol/L were observed in 2% of participants. Serum copper and selenium concentrations were below the reference range in 23% and 11% of participants, respectively. Micronutrient deficiencies including iron and vitamin B12, and apparent excess of folate are present in educated Australian female students of childbearing age, including those studying nutrition. The effects of dietary behaviours and food choices on markers of micronutrient status require further investigation. PMID:25401503

Fayet-Moore, Flavia; Petocz, Peter; Samman, Samir

2014-01-01

165

Transcobalamin-II variants, decreased vitamin B12 availability and increased risk of frailty  

Microsoft Academic Search

Objective  This project was designed to follow-up prior evidence that demonstrated a significant association between vitamin B12 transport and metabolism and the frailty syndrome in community-dwelling older women. The cross-sectional relationship between\\u000a genetic variants within six candidate genes along this pathway with serum methylmalonic acid (MMA) levels and frailty was\\u000a evaluated in this same population of older women.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  Baseline measures were

Amy M. Matteini; J. D. Walston; K. Bandeen-Roche; D. E. Arking; R. H. Allen; L. P. Fried; A. Chakravarti; S. P. Stabler; M. D. Fallin

2010-01-01

166

Malabsorption of vitamin B12 and intrinsic factor secretion during biguanide therapy.  

PubMed

In a survey of 46 randomly selected diabetic patients on biguanide therapy, 30% had malabsorption of vitamin B12. Withdrawal of the drug resulted in normal absorption in only half of those with malabsorption. In most patients with persistent malabsorption, the results of absorption tests with exogenous intrinsic factor suggested the diagnosis of coincidental intrinsic factor deficiency. Further considerations, however, led to the concept that biguanides can induce malabsorption by two different mechanisms. One of these is temporary and unrelated to intrinsic factor secretion and the other is permanent and mediated by depression of intrinsic factor secretion. PMID:6825978

Adams, J F; Clark, J S; Ireland, J T; Kesson, C M; Watson, W S

1983-01-01

167

Recommendations for diagnosis and management of metformin-induced vitamin B12 (Cbl) deficiency.  

PubMed

Metformin treatment is a known pharmacological cause of vitamin B12 (Cbl) deficiency with controversial responsible mechanisms. A possible diagnosis of this deficiency is based mainly on the combination of patient's medical history (usually long-term metformin use), clinical examination (possible neuropsychiatric symptoms and signs), laboratory studies which confirm a Cbl deficiency (haematological abnormalities, low serum Cbl levels, elevated serum total homocysteine and methylmalonic acid levels), and exclusion other causes of Cbl deficiency (as pernicious anaemia, food-cobalamin malabsorption syndrome, other drugs, etc.). In our review, recommendations for diagnosis and management of metformin-induced Cbl deficiency (MICD) in diabetic patients based on medical bibliography are presented and discussed. PMID:22770998

Mazokopakis, Elias E; Starakis, Ioannis K

2012-09-01

168

Comparative genomic analyses of nickel, cobalt and vitamin B12 utilization  

PubMed Central

Background Nickel (Ni) and cobalt (Co) are trace elements required for a variety of biological processes. Ni is directly coordinated by proteins, whereas Co is mainly used as a component of vitamin B12. Although a number of Ni and Co-dependent enzymes have been characterized, systematic evolutionary analyses of utilization of these metals are limited. Results We carried out comparative genomic analyses to examine occurrence and evolutionary dynamics of the use of Ni and Co at the level of (i) transport systems, and (ii) metalloproteomes. Our data show that both metals are widely used in bacteria and archaea. Cbi/NikMNQO is the most common prokaryotic Ni/Co transporter, while Ni-dependent urease and Ni-Fe hydrogenase, and B12-dependent methionine synthase (MetH), ribonucleotide reductase and methylmalonyl-CoA mutase are the most widespread metalloproteins for Ni and Co, respectively. Occurrence of other metalloenzymes showed a mosaic distribution and a new B12-dependent protein family was predicted. Deltaproteobacteria and Methanosarcina generally have larger Ni- and Co-dependent proteomes. On the other hand, utilization of these two metals is limited in eukaryotes, and very few of these organisms utilize both of them. The Ni-utilizing eukaryotes are mostly fungi (except saccharomycotina) and plants, whereas most B12-utilizing organisms are animals. The NiCoT transporter family is the most widespread eukaryotic Ni transporter, and eukaryotic urease and MetH are the most common Ni- and B12-dependent enzymes, respectively. Finally, investigation of environmental and other conditions and identity of organisms that show dependence on Ni or Co revealed that host-associated organisms (particularly obligate intracellular parasites and endosymbionts) have a tendency for loss of Ni/Co utilization. Conclusion Our data provide information on the evolutionary dynamics of Ni and Co utilization and highlight widespread use of these metals in the three domains of life, yet only a limited number of user proteins. PMID:19208259

Zhang, Yan; Rodionov, Dmitry A; Gelfand, Mikhail S; Gladyshev, Vadim N

2009-01-01

169

Role of maternal vitamin B12 on the metabolic health of the offspring: a contributor to the diabetes epidemic?  

Microsoft Academic Search

There is increasing evidence, in humans and other mammals, that periconceptional nutritional status influences health in adulthood. This is called ‘foetal programming’ and is likely to be mediated through DNA methylation. Micronutrients, especially B vitamins such as folic acid and vitamin B12 play crucial roles in providing methyl groups for such reactions. This is called epigenetic regulation and may provide

Ponnusamy Saravanan; Chitranjan S Yajnik

2010-01-01

170

Oral versus intramuscular administration of vitamin B12 for the treatment of patients with vitamin B12 deficiency: a pragmatic, randomised, multicentre, non-inferiority clinical trial undertaken in the primary healthcare setting (Project OB12)  

PubMed Central

Background The oral administration of vitamin B12 offers a potentially simpler and cheaper alternative to parenteral administration, but its effectiveness has not been definitively demonstrated. The following protocol was designed to compare the effectiveness of orally and intramuscularly administered vitamin B12 in the treatment of patients ≥65 years of age with vitamin B12 deficiency. Methods/design The proposed study involves a controlled, randomised, multicentre, parallel, non-inferiority clinical trial lasting one year, involving 23 primary healthcare centres in the Madrid region (Spain), and patients ≥65 years of age. The minimum number of patients required for the study was calculated as 320 (160 in each arm). Bearing in mind an estimated 8-10% prevalence of vitamin B12 deficiency among the population of this age group, an initial sample of 3556 patients will need to be recruited. Eligible patients will be randomly assigned to one of the two treatment arms. In the intramuscular treatment arm, vitamin B12 will be administered as follows: 1 mg on alternate days in weeks 1 and 2, 1 mg/week in weeks 3–8,and 1 mg/month in weeks 9–52. In the oral arm, the vitamin will be administered as: 1 mg/day in weeks 1–8 and 1 mg/week in weeks 9–52. The main outcome variable to be monitored in both treatment arms is the normalisation of the serum vitamin B12 concentration at weeks 8, 26 and 52; the secondary outcome variables include the serum concentration of vitamin B12 (in pg/ml), adherence to treatment, quality of life (EuroQoL-5D questionnaire), patient 3satisfaction and patient preferences. All statistical tests will be performed with intention to treat and per protocol. Logistic regression with random effects will be used to adjust for prognostic factors. Confounding factors or factors that might alter the effect recorded will be taken into account in analyses. Discussion The results of this study should help establish, taking quality of life into account, whether the oral administration of vitamin B12 is an effective alternative to its intramuscular administration. If this administration route is effective, it should provide a cheaper means of treating vitamin B12 deficiency while inducing fewer adverse effects. Having such an alternative would also allow patient preferences to be taken into consideration at the time of prescribing treatment. Trial registration This trial has been registered with ClinicalTrials.gov, number NCT 01476007, and under EUDRACT number 2010-024129-20. PMID:22650964

2012-01-01

171

Megaloblastic anemia in patients receiving total parenteral nutrition without folic acid or vitamin B12 supplementation.  

PubMed

Pancytopenia developed in four patients receiving postoperatively total parenteral nutrition (TPN). Symptoms and signs were related mainly to underlying bowel disease. Hematologic abnormalities, first noted from 4 to 7 weeks following institution of TPN, consisted of normocytic anemia (mean decrease in hemoglobin value, 2.2 g/dL), occasional macrocytes being noted, leukopenia (range of leukocyte counts, 1.2 to 3.6 X 10(9) L), some hypersegmented neutrophils being detected, and clinically significant thrombocytopenia (range of platelet counts, 25 to 52 X 10(9)/L). In all patients the bone marrow showed megaloblastic changes, with ring sideroblasts, although pyridoxine was included in the TPN regimens. Serum vitamin B12 values were normal in one patient and at the lower limit of normal in the other two patients in whom it was measured, while serum or erythrocyte folate values, or both, were reduced in three patients. Full hematologic response was observed in the four patients after folic acid replacement therapy; leukocytosis and thrombocytosis were noted in three. Thus, folic acid and possibly vitamin B12 should be added routinely to TPN regimens to prevent deficiency of either substance. PMID:406033

Denburg, J; Bensen, W; Ali, M A; McBride, J; Ciok, J

1977-07-23

172

Folate and vitamin B12 levels in patients with oral lichen planus, stomatitis or glossitis.  

PubMed

Forty-one patients with oral lesions and symptoms were enrolled in the study. Their ages ranged from 16 to 79 years with a mean age of 48.5 years. They were divided into two groups. Group I consisted of 25 patients with oral lichen planus and group II consisted of 16 patients with stomatitis or glossitis. Their complete blood counts, hemoglobin typing, serum and red cell folate, and serum vitamin B12 levels were studied. The results revealed low red cell folate levels in 11 out of 25 patients (44%) in group I and 9 out of 16 patients (56%) in group II. The serum vitamin B12 levels were within normal range in both groups. They were defined as having folate deficiency (n = 10), folate deficient erythropoiesis (n = 3) and folate depletion (n = 7). None of them had anemia nor macrocytes. Therefore, folate levels should be investigated in patients with oral lesions and symptoms especially those with risk factors of age, poor nutrition or systemic diseases. When suspected, daily folic acid supplements should be given. PMID:11944731

Thongprasom, K; Youngnak, P; Aneksuk, V

2001-09-01

173

Microbial production of propionic acid and vitamin B12 using molasses or sugar.  

PubMed

With a cell concentration of 125 g dry biomass l-1 and a dilution rate of 0.1 h-1, Propionibacterium acidipropionici produces 30 g propionic acid l-1 from sugar with a productivity of 3 g l-1 h-1. The yield of propionic acid is approx. 0.36-0.45 g propionic acid g-1 sucrose and is independent of the dilution rate and cell concentration. Acetic acid is an unwanted by-product in the production of propionic acid. The concentration of acetic acid only increases slightly when the cell concentration is increased. A two-stage fermentation process was developed for the conversion of sugar or molasses of various types to propionic acid and vitamin B12. By fermentation of blackstrap molasses (from sugar beet and sugar cane) in the first fermentation stage 17.7 g propionic acid l-1 with a yield of 0.5 g propionic acid g-1 carbohydrate was produced with a dilution rate of 0.25 h-1. In the second stage 49 mg vitamin B12 1-1 was produced at a dilution rate of 0.03 h-1. PMID:7765100

Quesada-Chanto, A; Afschar, A S; Wagner, F

1994-06-01

174

[Old or new medicine? Vitamin B12 and peripheral nerve neuropathy].  

PubMed

Methylcobalamin is a vitamin B12 analog that is necessary for nervous system maintenance. Although methylcobalamin has some positive effects on peripheral nervous system disorders, the mechanism through which it affects neurons are not entirely known. Recent studies have revealed its intracellular signaling pathway and some of its molecular actions on neurons. In this article, I review interactions between methylcobalamin and neurons that have been revealed through in vitro studies, in vivo studies, and clinical use. Methylcobalamin participates in nervous system maintenance through several mechanisms. Methylcobalamin is an active form of vitamin B12, and a coenzyme of methionine synthase, which is required for DNA and protein methylation. In addition, methylcobalamin facilitates neurite outgrowth and inhibits neural apoptosis through the Erk1/2 and Akt signaling pathways. Treatment with high doses of methylcobalamin ameliorates symptoms and negative electrophysiological findings in animal models of peripheral nerve neuropathy and in patients with carpal tunnel syndrome and amyotrophic lateral sclerosis. Thus, high-dose methylcobalamin has great potential for treating nervous system disorders. Further investigations with methylcobalamin may help elucidate its mechanisms of action, which may further enable us to treat many nervous system disorders. PMID:24018744

Tanaka, Hiroyuki

2013-09-01

175

Effects of dietary supplements of folic acid and vitamin B12 on metabolism of dairy cows in early lactation.  

PubMed

The present experiment was undertaken to determine the effects of dietary supplements of folic acid and vitamin B12 given from 3 wk before to 8 wk after calving on lactational performance and metabolism of 24 multiparous Holstein cows assigned to 6 blocks of 4 cows each according to their previous milk production. Supplementary folic acid at 0 or 2.6 g/d and vitamin B12 at 0 or 0.5 g/d were used in a 2 x 2 factorial arrangement. Supplementary folic acid increased milk production from 38.0 +/- 0.9 to 41.4 +/- 1.0 kg/d and milk crude protein yield from 1.17 +/- 0.02 to 1.25 +/- 0.03 kg/d. It also increased plasma Gly, Ser, Thr, and total sulfur AA, decreased Asp, and tended to increase plasma Met. Supplementary B12 decreased milk urea N, plasma Ile, and Leu and tended to decrease Val but increased homocysteine, Cys, and total sulfur AA. Liver concentration of phospholipids was higher in cows fed supplementary B12. Plasma and liver concentrations of folates and B12 were increased by their respective supplements, but the increase in plasma folates and plasma and liver B12 was smaller for cows fed the 2 vitamins together. In cows fed folic acid supplements, supplementary B12 increased plasma glucose and alanine, tended to decrease plasma biotin, and decreased Km of the methylmalonyl-coenzyme A mutase in hepatic tissues following addition of deoxyadenosylcobalamin, whereas it had no effect when cows were not fed folic acid supplements. There was no treatment effect on plasma nonesterified fatty acids as well as specific activity and gene expression of Met synthase and methylmalonyl-coenzyme A mutase in the liver. Ingestion of folic acid supplements by cows fed no supplementary B12 increased total lipid and triacylglycerols in liver, whereas these supplements had no effect in cows supplemented with B12. The increases in milk and milk protein yields due to folic acid supplements did not seem to be dependent on the vitamin B12 supply. However, when vitamin B12 was given in combination with folic acid, utilization of the 2 vitamins seems to be increased, probably more so in extrahepatic tissues. Metabolic efficiency seems also to be improved as suggested by similar lactational performance and dry matter intake for cows fed supplementary folic acid but increased plasma glucose and decreased hepatic lipids in cows fed folic acid and vitamin B12 together. PMID:17582128

Graulet, B; Matte, J J; Desrochers, A; Doepel, L; Palin, M-F; Girard, C L

2007-07-01

176

Deficiencies of the Microelements, Folate and Vitamin B12 in Women of the Child Bearing Ages in Gorgan, Northern Iran  

PubMed Central

Background: The deficiencies of folic acid, vitamin B12, and microelements during pregnancy may affect the health of newborns. Objectives: To assess the serum levels of folate, vitamin B12, iron, zinc and copper in healthy women of the childbearing ages in Gorgan, northern Iran. Methodology: This descriptive, cross-sectional study was carried out on 100 women of childbearing ages in northern Iran during November 2007-March 2008. The serum levels of folate, vitamin B12, iron, copper and zinc were evaluated by laboratory tests. Results: Iron, copper , folate, vitamin B12 deficiencies and folate with vitamin B12 deficiency were detected in 13%, 32% , 13% , 32% and 11% women of the childbearing ages, respectively . According to the ethnicity, vitamin B12, folate and iron deficiencies in the Sistani group were observed in 38.3%, 12.9% and 12.9% of the women, respectively. In the native Fars group, the above mentioned deficiencies were found in 31.1%, 13.4% and 7.5% of the subjects. Folate and vitamin B12 deficiencies were observed in the urban habitant in 32.7% and 11.5 % of the subjects as compared to those in the rural habitant (in 30.4% and 15.2%of the subjects respectively). The folate deficiencies in the under and above 18 years old subjects were 22.2% and 9.9%, respectively. Conclusions: This study showed that the deficiency of the micronutrients was considerable in women of the childbearing ages in Gorgan, northern Iran. PMID:23905113

Sedehi, Maliheh; Behnampour, Naser; Golalipour, Mohammad Jafar

2013-01-01

177

Impact of Vitamin B12 on Formation of the Tetrachloroethene Reductive Dehalogenase in Desulfitobacterium hafniense Strain Y51  

PubMed Central

Corrinoids are essential cofactors of reductive dehalogenases in anaerobic bacteria. Microorganisms mediating reductive dechlorination as part of their energy metabolism are either capable of de novo corrinoid biosynthesis (e.g., Desulfitobacterium spp.) or dependent on exogenous vitamin B12 (e.g., Dehalococcoides spp.). In this study, the impact of exogenous vitamin B12 (cyanocobalamin) and of tetrachloroethene (PCE) on the synthesis and the subcellular localization of the reductive PCE dehalogenase was investigated in the Gram-positive Desulfitobacterium hafniense strain Y51, a bacterium able to synthesize corrinoids de novo. PCE-depleted cells grown for several subcultivation steps on fumarate as an alternative electron acceptor lost the tetrachloroethene-reductive dehalogenase (PceA) activity by the transposition of the pce gene cluster. In the absence of vitamin B12, a gradual decrease of the PceA activity and protein amount was observed; after 5 subcultivation steps with 10% inoculum, more than 90% of the enzyme activity and of the PceA protein was lost. In the presence of vitamin B12, a significant delay in the decrease of the PceA activity with an ?90% loss after 20 subcultivation steps was observed. This corresponded to the decrease in the pceA gene level, indicating that exogenous vitamin B12 hampered the transposition of the pce gene cluster. In the absence or presence of exogenous vitamin B12, the intracellular corrinoid level decreased in fumarate-grown cells and the PceA precursor formed catalytically inactive, corrinoid-free multiprotein aggregates. The data indicate that exogenous vitamin B12 is not incorporated into the PceA precursor, even though it affects the transposition of the pce gene cluster. PMID:22961902

Reinhold, Anika; Westermann, Martin; Seifert, Jana; von Bergen, Martin; Schubert, Torsten

2012-01-01

178

Vitamin B12 Metabolism during Pregnancy and in Embryonic Mouse Models  

PubMed Central

Vitamin B12 (cobalamin, Cbl) is required for cellular metabolism. It is an essential coenzyme in mammals for two reactions: the conversion of homocysteine to methionine by the enzyme methionine synthase and the conversion of methylmalonyl-CoA to succinyl-CoA by the enzyme methylmalonyl-CoA mutase. Symptoms of Cbl deficiency are hematological, neurological and cognitive, including megaloblastic anaemia, tingling and numbness of the extremities, gait abnormalities, visual disturbances, memory loss and dementia. During pregnancy Cbl is essential, presumably because of its role in DNA synthesis and methionine synthesis; however, there are conflicting studies regarding an association between early pregnancy loss and Cbl deficiency. We here review the literature about the requirement for Cbl during pregnancy, and summarized what is known of the expression pattern and function of genes required for Cbl metabolism in embryonic mouse models. PMID:24025485

Moreno-Garcia, Maira A.; Rosenblatt, David S.; Jerome-Majewska, Loydie A.

2013-01-01

179

The cis influence of the corrin in vitamin B12 models  

NASA Astrophysics Data System (ADS)

Density Functional Theory (DFT) and Quantum Theory of Atoms in Molecules (QTAIM) calculations on [NH3[Co(III)(C10-X-corrin)]-CH3]+, where the C10-H of corrin is replaced by electron-donating or -withdrawing groups, X, explore the cis influence in these vitamin B12 models. As the electron donating ability of X increases, a normal trans influence is observed: the Co-NH3 bond weakens while the Co-CH3 bond strengthens. Surprisingly, though, the Co-CH3 bond dissociation energy decreases monotonically as the Co-C bond strengthens. This is found to be a consequence of the extent of shortening of the Co-NH3 during the homolysis reaction.

Govender, Penny P.; Navizet, Isabelle; Perry, Christopher B.; Marques, Helder M.

2012-10-01

180

Mechanism of perfluoroalkyl halide toxicity: catalysis of perfluoroalkylation by reduced forms of cobalamin (vitamin B12).  

PubMed

Perfluoroalkyl halides (PFHs) are synthetic products widely used in various fields. Perfluorooctyl bromide (PFB) is used in medicine as a component of blood substitutes and for artificial lung ventilation. In both cases, it is considered a completely inert compound acting as a solvent for oxygen. However, there are many reports of PFH-induced intoxication, including lethal cases. Mechanisms underlying toxic effects of this compound remain unknown. In this study, we demonstrate that the reduced form of cobalamin (vitamin B12) typical for B12-dependent enzymes can catalyze the reactions of perfluoroalkylation, aromatic substitution, or addition by double bonds. Synthesis of perfluoro derivatives from PFHs during catalysis by cob(I)alamin-like super nucleophiles is a new possible mechanism responsible for in vivo formation of highly toxic compounds from "chemically inert" substances widely used in medicine. Catalytic perfluoroalkylation might possibly contribute to nitric oxide depletion and modulation of activity of guanylate cyclase, cytochromes, NO-synthases, and other heme-containing proteins. PMID:14756634

Beda, N V; Nedospasov, A A

2003-12-01

181

Lactobacillus rossiae, a Vitamin B12 Producer, Represents a Metabolically Versatile Species within the Genus Lactobacillus  

PubMed Central

Lactobacillus rossiae is an obligately hetero-fermentative lactic acid bacterium, which can be isolated from a broad range of environments including sourdoughs, vegetables, fermented meat and flour, as well as the gastrointestinal tract of both humans and animals. In order to unravel distinctive genomic features of this particular species and investigate the phylogenetic positioning within the genus Lactobacillus, comparative genomics and phylogenomic approaches, followed by functional analyses were performed on L. rossiae DSM 15814T, showing how this type strain not only occupies an independent phylogenetic branch, but also possesses genomic features underscoring its biotechnological potential. This strain in fact represents one of a small number of bacteria known to encode a complete de novo biosynthetic pathway of vitamin B12 (in addition to other B vitamins such as folate and riboflavin). In addition, it possesses the capacity to utilize an extensive set of carbon sources, a characteristic that may contribute to environmental adaptation, perhaps enabling the strain's ability to populate different niches. PMID:25264826

De Angelis, Maria; Bottacini, Francesca; Fosso, Bruno; Kelleher, Philip; Calasso, Maria; Di Cagno, Raffaella; Ventura, Marco; Picardi, Ernesto; van Sinderen, Douwe; Gobbetti, Marco

2014-01-01

182

Lactobacillus rossiae, a Vitamin B12 Producer, Represents a Metabolically Versatile Species within the Genus Lactobacillus.  

PubMed

Lactobacillus rossiae is an obligately hetero-fermentative lactic acid bacterium, which can be isolated from a broad range of environments including sourdoughs, vegetables, fermented meat and flour, as well as the gastrointestinal tract of both humans and animals. In order to unravel distinctive genomic features of this particular species and investigate the phylogenetic positioning within the genus Lactobacillus, comparative genomics and phylogenomic approaches, followed by functional analyses were performed on L. rossiae DSM 15814T, showing how this type strain not only occupies an independent phylogenetic branch, but also possesses genomic features underscoring its biotechnological potential. This strain in fact represents one of a small number of bacteria known to encode a complete de novo biosynthetic pathway of vitamin B12 (in addition to other B vitamins such as folate and riboflavin). In addition, it possesses the capacity to utilize an extensive set of carbon sources, a characteristic that may contribute to environmental adaptation, perhaps enabling the strain's ability to populate different niches. PMID:25264826

De Angelis, Maria; Bottacini, Francesca; Fosso, Bruno; Kelleher, Philip; Calasso, Maria; Di Cagno, Raffaella; Ventura, Marco; Picardi, Ernesto; van Sinderen, Douwe; Gobbetti, Marco

2014-01-01

183

A human vitamin B12 trafficking protein uses glutathione transferase activity for processing alkylcobalamins.  

PubMed

Pathways for tailoring and processing vitamins into active cofactor forms exist in mammals that are unable to synthesize these cofactors de novo. A prerequisite for intracellular tailoring of alkylcobalamins entering from the circulation is removal of the alkyl group to generate an intermediate that can subsequently be converted into the active cofactor forms. MMACHC, a cytosolic cobalamin trafficking chaperone, has been shown recently to catalyze a reductive decyanation reaction when it encounters cyanocobalamin. In this study, we demonstrate that this versatile protein catalyzes an entirely different chemical reaction with alkylcobalamins using the thiolate of glutathione for nucleophilic displacement to generate cob(I)alamin and the corresponding glutathione thioether. Biologically relevant thiols, e.g. cysteine and homocysteine, cannot substitute for glutathione. The catalytic turnover numbers for the dealkylation of methylcobalamin and 5'-deoxyadenosylcobalamin by MMACHC are 11.7 +/- 0.2 and 0.174 +/- 0.006 h(-1) at 20 degrees C, respectively. This glutathione transferase activity of MMACHC is reminiscent of the methyltransferase chemistry catalyzed by the vitamin B(12)-dependent methionine synthase and is impaired in the cblC group of inborn errors of cobalamin disorders. PMID:19801555

Kim, Jihoe; Hannibal, Luciana; Gherasim, Carmen; Jacobsen, Donald W; Banerjee, Ruma

2009-11-27

184

Vitamin B12 Supplementation to Mink (Mustela vison) in the Prevention of Feed-Induced Iron Deficiency Anaemia: I. Effect on Growth Performance and Fur Quality Characteristics  

Microsoft Academic Search

Vitamin B12 supplementation in the prevention of feed-induced iron deficiency anaemia was evaluated with six treatment groups of mink kits, comprising a control group and five groups fed an anaemiogenic diet either unsupplemented, supplemented with vitamin B12 orally, or by intramuscular injection, with iron therapy by ferrous fumarate and cysteine, and iron therapy plus vitamin B12 orally. Unsupplemented animals showed

Anne-Helene Tauson; Maria Neil

1993-01-01

185

Investigation on the pH-dependent binding of vitamin B12 and lysozyme by fluorescence and absorbance  

NASA Astrophysics Data System (ADS)

The binding reaction between vitamin B12 (B12, cyanocobalamin) and lysozyme (Lys) has been investigated by fluorescence, synchronous fluorescence, ultraviolet-vis (UV) absorbance, and three-dimensional fluorescence. The intrinsic fluorescence of Lys was strongly quenched by the addition of B12 in different pH buffer solutions (pH 3.4, 7.4, and 9.0) and the spectroscopic observations are mainly rationalized in terms of a static quenching process at lower concentration of B12 ( CB12/ CLys < 5) and a combined quenching process at higher concentration of B12 ( CB12/ CLys > 5). The structural characteristics of B12 and Lys were probed, and their binding affinities were determined under different pH conditions (pH 3.4, 7.4, and 9.0). The effect of B12 on the conformation of Lys was analyzed using UV, synchronous fluorescence and three-dimensional fluorescence under different pH conditions. These results indicate that the binding of B12 to Lys causes apparent change in the secondary or tertiary structures of Lys. Furthermore, the effect of Zn 2+ on the binding constant of B12 with Lys under various pH conditions (pH 3.4, 7.4, and 9.0) was also studied.

Li, Daojin; Yang, Yumin; Cao, Xinxiang; Xu, Chen; Ji, Baoming

2012-01-01

186

Bestimmung der wasserlöslichen Vitamine B 1 , B 2 , B 6 und B 12 in Milch durch HPLC  

Microsoft Academic Search

Summary Simple methods of determining the water-soluble vitamins B1, B2, B6 and B12 in milk by HPLC are described. Compared to existing procedures, the following improvements can be realized. The oxidation of vitamin B1 to thiochrome is stopped by the addition of sodium sulphite. This step significantly increases repeatability. Thiochrome is then extracted with butan-1-ol, which results in fewer co-extracts

Roland Gauch; Urs Leuenberger; Urs Müller

1992-01-01

187

CO2 and vitamin B12 interactions determine bioactive trace metal requirements of a subarctic Pacific diatom  

PubMed Central

Phytoplankton growth can be limited by numerous inorganic nutrients and organic growth factors. Using the subarctic diatom Attheya sp. in culture studies, we examined how the availability of vitamin B12 and carbon dioxide partial pressure (pCO2) influences growth rate, primary productivity, cellular iron (Fe), cobalt (Co), zinc (Zn) and cadmium (Cd) quotas, and the net use efficiencies (NUEs) of these bioactive trace metals (mol C fixed per mol cellular trace metal per day). Under B12-replete conditions, cells grown at high pCO2 had lower Fe, Zn and Cd quotas, and used those trace metals more efficiently in comparison with cells grown at low pCO2. At high pCO2, B12-limited cells had ?50% lower specific growth and carbon fixation rates, and used Fe ?15-fold less efficiently, and Zn and Cd ?3-fold less efficiently, in comparison with B12-replete cells. The observed higher Fe, Zn and Cd NUE under high pCO2/B12-replete conditions are consistent with predicted downregulation of carbon-concentrating mechanisms. Co quotas of B12-replete cells were ?5- to 14-fold higher in comparison with B12-limited cells, suggesting that >80% of cellular Co of B12-limited cells was likely from B12. Our results demonstrate that CO2 and vitamin B12 interactively influence growth, carbon fixation, trace metal requirements and trace metal NUE of this diatom. This suggests the need to consider complex feedback interactions between multiple environmental factors for this biogeochemically critical group of phytoplankton in the last glacial maximum as well as the current and future changing ocean. PMID:21248860

King, Andrew L; Sanudo-Wilhelmy, Sergio A; Leblanc, Karine; Hutchins, David A; Fu, Feixue

2011-01-01

188

Substitution of Co alpha-(5-hydroxybenzimidazolyl)cobamide (factor III) by vitamin B12 in Methanobacterium thermoautotrophicum.  

PubMed Central

Methanobacterium thermoautotrophicum grown on mineral medium contains 120 nmol of Co alpha-(5-hydroxybenzimidazolyl)cobamides (derivatives of factor III) per g of dry cell mass as the sole cobamide. The bacterium assimilated several corrinoids and benzimidazole bases during autotrophic growth. The corrinoids were converted into factor III; however, after three transfers in 5,6-dimethylbenzimidazole (200 microM)-supplemented mineral medium, derivatives of factor III were completely replaced by derivatives of vitamin B12, which is atypical for methanogens. The total cobamide content of these cells and their growth rate were not affected compared with factor III-containing cells. Therefore, the high cobamide content rather than a particular type of cobamide is required for metabolism of methanogens. Derivatives of factor III are not essential cofactors of cobamide-containing enzymes from methanogenic bacteria, but they are the result of a unique biosynthetic ability of these archaebacteria. The cobamide biosynthesis include unspecific enzymes, which made it possible either to convert non-species-derived corrinoids into derivatives of factor III or to synthesize other types of cobamides than factor III. The cobamide biosynthesis is regulated by its end product. In addition, the uptake of extracellular cobamides is controlled, and the assimilated corrinoids regulate cellular cobamide biosynthesis. PMID:3597318

Stupperich, E; Steiner, I; Eisinger, H J

1987-01-01

189

Recovery of Vitamin B12 and cephalosporin-C from aqueous solutions by adsorption on non-ionic polymeric adsorbents  

Microsoft Academic Search

The study of separation and purification processes of fermentation products is most important for their commercial success. Both the optimisation and the scale-up of such operations require a study of the process fundamentals. Mathematical models have been developed and used to predict the effects of parameter changes in the adsorption based recovery process. The adsorption of Vitamin B12 (VB12) and

Ana Mar??a Ramos; Marta Otero; Alirio E. Rodrigues

2004-01-01

190

Spinal MR imaging in Vitamin B12 deficiency: Case series; differential diagnosis of symmetrical posterior spinal cord lesions.  

PubMed

We report three cases of Vitamin B12 deficiency with symmetrical posterior spinal cord lesions and discuss the differential diagnosis, some of which are not well known. Because the degree of resolution of the clinical symptoms in subacute combined degeneration depends on early detection, MRI findings should not be missed. PMID:23956577

Sen, Anitha; Chandrasekhar, Kesavadas

2013-04-01

191

Relationship between metformin use, vitamin B12 deficiency, hyperhomocysteinemia and vascular complications in patients with type 2 diabetes.  

PubMed

Aim of the study was to clarify the relationship between metformin-induced vitamin B12 (B12) deficiency, hyperhomocysteinemia and vascular complications in patients with type 2 diabetes. Serum B12 concentrations, homocysteine plasma levels, the presence of retinopathy and history of macroangiopathy (stroke or coronary heart disease) were analyzed in patients without renal dysfunction (serum creatinine<115 ?mol/L). Firstly, B12 status was analyzed in 62 consecutive metformin-treated patients. Secondly, the relationship between B12, homocysteine and vascular complications was analyzed in 46 metformin-treated and 38 age- and sex-matched non-metformin-treated patients. Among the 62 consecutive metformin-treated patients, B12 was deficient (<150 pmol/L) in 8 (13%) and borderline-deficient (150-220 pmol/L) in 18 (29%): the larger the metformin dosage, the lower the B12 (P=0.02, Spearman's ?=-0.30). There were independent correlations between metformin use and B12 lowering (P=0.02, r = -0.25), and B12 lowering and elevation of homocysteine (P<0.01, r=-0.34). Elevation of homocysteine was a risk for retinopathy (P=0.02, OR 1.26, 95%CI 1.04-1.52). There was no significant relation between homocysteine and macroangiopathy. Correlation between B12 and homocysteine was stronger in metformin-treated (P<0.01, r=-0.48) than non-metformin-treated (P=0.04, r=-0.38) patients. In ten B12 deficient patients, B12 supplementation (1,500 ?g/day) for 2.2±1.0 months with continued use of metformin raised B12 levels: 152±42 and 299±97 pmol/L before and after treatment, respectively (P<0.01). Metformin-induced B12 lowering in diabetes was associated with elevation of homocysteine, and hyperhomocysteinemia was independently related to retinopathy. Metformin-induced B12 deficiency was correctable with B12 supplementation. PMID:24018893

Sato, Yuka; Ouchi, Kenjiro; Funase, Yoshiko; Yamauchi, Keishi; Aizawa, Toru

2013-01-01

192

Lack of megalin expression in adult human terminal ileum suggests megalin?independent cubilin/amnionless activity during vitamin B12 absorption  

PubMed Central

Abstract Cubilin plays an essential role in terminal ileum and renal proximal tubules during absorption of vitamin B12 and ligands from the glomerular ultrafiltrate. Cubilin is coexpressed with amnionless, and cubilin and amnionless are mutually dependent on each other for correct processing to the plasma membrane upon synthesis. Patients with defects in either protein suffer from vitamin B12?malabsorption and in some cases proteinuria. Cubilin lacks a transmembrane region and signals for endocytosis and is dependent on a transmembrane coreceptor during internalization. Amnionless has been shown to be able to mediate internalization of cubilin in a cell?based model system. Cubilin has additionally been suggested to function together with megalin, and a recent study of megalin?deficient patients indicates that uptake of cubilin ligands in the kidney is critically dependent on megalin. To further investigate the potential role of amnionless and megalin in relation to cubilin function in terminal ileum and vitamin B12 uptake, we initiated a study of CUBN/cubilin, AMN/amnionless, and LRP2/megalin expression in adult human terminal ileum. Our study is the first to reveal the expression pattern of cubilin, amnionless, and megalin in adult human terminal ileum, where cubilin and amnionless localize to the epithelial cells. Surprisingly, we did not detect any megalin protein in adult terminal ileum and consistently, only extremely low amounts of LRP2 mRNA. Our data therefore advocate that cubilin and amnionless act independently of megalin in adult terminal ileum and that the cubilin?megalin interdependency accordingly should be considered as tissue and ligand specific. PMID:25052491

Jensen, Louise L.; Andersen, Rikke K.; Hager, Henrik; Madsen, Mette

2014-01-01

193

Vitamin B12-Mediated Restoration of Defective Anaerobic Growth Leads to Reduced Biofilm Formation in Pseudomonas aeruginosa  

PubMed Central

Pseudomonas aeruginosa undergoes cell elongation and forms robust biofilms during anaerobic respiratory growth using nitrate (NO3?) as an alternative electron acceptor. Understanding the mechanism of cell shape change induced upon anaerobiosis is crucial to the development of effective treatments against P. aeruginosa biofilm infection. Here, we uncovered the molecular basis of anaerobiosis-triggered cell elongation and identified vitamin B12 to be a molecule that can reinstate defective anaerobic growth of P. aeruginosa. The ratio of total cellular DNA content to protein content was significantly decreased in the PAO1 strain grown under anaerobic conditions, indicating that DNA replication is impaired during anaerobic growth. Anaerobic growth of PAO1 reached a higher cell density in the presence of vitamin B12, an essential coenzyme of class II ribonucleotide reductase. In addition, cell morphology returned to a normal rod shape and transcription of stress-response genes was downregulated under the same anaerobic growth conditions. These results suggest that vitamin B12, the production of which was suppressed during anaerobic growth, can restore cellular machineries for DNA replication and therefore facilitate better anaerobic growth of P. aeruginosa with normal cell division. Importantly, biofilm formation was substantially decreased when grown with vitamin B12, further demonstrating that anaerobiosis-induced cell elongation is responsible for robust biofilm formation. Taken together, our data reveal mechanistic details of a morphological change that naturally occurs during anaerobic growth of P. aeruginosa and illustrates the ability of vitamin B12 to modulate the biofilm-forming capacity of P. aeruginosa under such condition. PMID:22371376

Lee, Kang-Mu; Go, Junhyeok; Yoon, Mi Young; Park, Yongjin; Kim, Sang Cheol; Yong, Dong Eun

2012-01-01

194

[Effect of betaine hydrochloride on broiler chickens when used alone or in combination with vitamin B12].  

PubMed

The studies were carried out with 2287 broilers aged from 3 to 56 days, divided when one-day-old into four equal groups. The first group were fed the common ration and served as controls. The remaining three groups were experimental, the broilers of the second group being offered the basic common ration enriched with 0.2 per cent betaine. The third group were also given the ordinary ration, however, they received in the drinking water some 10 mug vitamin BUI per one kilogram feed each. The fourth group received both betaine and vitamin B12 at the rates indicated. Results showed that betaine hydrochloride offered either alone or in combination with vitamin B12 contributes to increasing the liveweight gain of broilers in the course of the starter period, but its use in doses of 0.2 per cent in the finishing period is not effective. PMID:1014365

Bogdanov, M; Filipova, R; Tsvetkov, S

1976-01-01

195

Serum folate and vitamin B12 levels in acute and chronic renal disease. Effect of peritoneal dialysis.  

PubMed

Serum folate and vitamin B(12) levels have been measured in 32 patients with renal failure. The initial mean serum folate level was raised above normal in seven patients with acute renal failure whereas the mean level in eight patients severely ill from chronic renal failure was significantly lower than normal. Serum folate levels fell during peritoneal dialysis and rose between dialyses in all these patients and also in one patient who was dialysed for acute pancreatitis.The mean serum B(12) level was raised in patients with both acute and chronic renal failure, but there was no consistent change in serum B(12) level during dialysis.Hypersegmented polymorphs were present in the peripheral blood film of most of the patients with acute or chronic renal failure. Their presence bore no relation to the clinical state, blood urea, serum folate, or serum B(12) level of the patients. PMID:5776209

Sevitt, L H; Hoffbrand, A V

1969-04-01

196

Chlamydomonas reinhardtii thermal tolerance enhancement mediated by a mutualistic interaction with vitamin B12-producing bacteria  

PubMed Central

Temperature is one of the most important environmental factors affecting the growth and survival of microorganisms and in light of current global patterns is of particular interest. Here, we highlight studies revealing how vitamin B12 (cobalamin)-producing bacteria increase the fitness of the unicellular alga Chlamydomonas reinhardtii following an increase in environmental temperature. Heat stress represses C. reinhardtii cobalamin-independent methionine synthase (METE) gene expression coinciding with a reduction in METE-mediated methionine synthase activity, chlorosis and cell death during heat stress. However, in the presence of cobalamin-producing bacteria or exogenous cobalamin amendments C. reinhardtii cobalamin-dependent methionine synthase METH-mediated methionine biosynthesis is functional at temperatures that result in C. reinhardtii death in the absence of cobalamin. Artificial microRNA silencing of C. reinhardtii METH expression leads to nearly complete loss of cobalamin-mediated enhancement of thermal tolerance. This suggests that methionine biosynthesis is an essential cellular mechanism for adaptation by C. reinhardtii to thermal stress. Increased fitness advantage of METH under environmentally stressful conditions could explain the selective pressure for retaining the METH gene in algae and the apparent independent loss of the METE gene in various algal species. Our results show that how an organism acclimates to a change in its abiotic environment depends critically on co-occurring species, the nature of that interaction, and how those species interactions evolve. PMID:23486253

Xie, Bo; Bishop, Shawn; Stessman, Dan; Wright, David; Spalding, Martin H; Halverson, Larry J

2013-01-01

197

Subacute combined degeneration of the spinal cord despite prophylactic vitamin B12 treatment.  

PubMed

We describe a 35 year-old man presenting with a four-week history of non-painful limb paraesthesias and unsteady gait causing falls. On examination he had an ataxic gait associated with dorsal column sensory loss. He had a medical history of a partial gastrectomy six years prior and anaemia. He had received monthly intramuscular hydroxycobalamin injections since the gastrectomy. Laboratory tests revealed normal vitamin B12 and holotranscobalamin levels, a reduced serum caeruloplasmin of 0.05 g/L (normal: 0.22-0.58 g/L), a copper-to-caeruloplasmin ratio of 1.9 ?mol/L (11.0-22.0 ?mol/L) and a reduced 24-hour urinary copper concentration of <0.30 ?mol/L (0-0.3 ?mol/L). Cerebrospinal fluid analysis, nerve conduction studies, electromyography and visual-evoked responses were unremarkable. MRI revealed abnormal hyperintense signal in the cervical dorsal columns. Hypocupric myelopathy was diagnosed and he was treated with daily oral elemental copper. Three months later, his walking and balance had improved although there was no change noted on MRI. PMID:22342235

Tsang, Benjamin K-T; Crump, Nicholas; Macdonell, Richard A

2012-06-01

198

Sub-Optimal Vitamin B-12 Levels among ART-Naïve HIV-Positive Individuals in an Urban Cohort in Uganda  

PubMed Central

Malnutrition is common among HIV-infected individuals and is often accompanied by low serum levels of micronutrients. Vitamin B-12 deficiency has been associated with various factors including faster HIV disease progression and CD4 depletion in resource-rich settings. To describe prevalence and factors associated with sub-optimal vitamin B-12 levels among HIV-infected antiretroviral therapy (ART) naïve adults in a resource-poor setting, we performed a cross-sectional study with a retrospective chart review among individuals attending either the Mulago-Mbarara teaching hospitals’ Joint AIDS Program (MJAP) or the Infectious Diseases Institute (IDI) clinics, in Kampala, Uganda. Logistic regression was used to determine factors associated with sub-optimal vitamin B-12. The mean vitamin B-12 level was 384 pg/ml, normal range (200–900). Sub-optimal vitamin B-12 levels (<300 pg/ml) were found in 75/204 (36.8%). Twenty-one of 204 (10.3%) had vitamin B-12 deficiency (<200 pg/ml) while 54/204 (26.5%) had marginal depletion (200–300 pg/ml). Irritable mood was observed more among individuals with sub-optimal vitamin B-12 levels (OR 2.5, 95% CI; 1.1–5.6, P?=?0.03). Increasing MCV was associated with decreasing serum B-12 category; 86.9 fl (±5.1) vs. 83 fl (±8.4) vs. 82 fl (±8.4) for B-12 deficiency, marginal and normal B-12 categories respectively (test for trend, P?=?0.017). Compared to normal B-12, individuals with vitamin B-12 deficiency had a longer known duration of HIV infection: 42.2 months (±27.1) vs. 29.4 months (±23.8; P?=?0.02). Participants eligible for ART (CD4<350 cells/µl) with sub-optimal B-12 had a higher mean rate of CD4 decline compared to counterparts with normal B-12; 118 (±145) vs. 22 (±115) cells/µl/year, P?=?0.01 respectively. The prevalence of a sub-optimal vitamin B-12 was high in this HIV-infected, ART-naïve adult clinic population in urban Uganda. We recommend prospective studies to further clarify the causal relationships of sub-optimal vitamin B-12, and explore the role of vitamin B-12 supplementation in immune recovery. PMID:22768330

Semeere, Aggrey S.; Nakanjako, Damalie; Ddungu, Henry; Kambugu, Andrew; Manabe, Yukari C.; Colebunders, Robert

2012-01-01

199

Isotope-dilution assay for urinary methylmalonic acid in the diagnosis of vitamin B12 deficiency. A prospective clinical evaluation  

SciTech Connect

Vitamin B12 deficiency is a frequently considered diagnosis for which there is no single, commonly available and accurate test. A urinary methylmalonic acid assay using gas chromatography-mass spectrometry has been proposed as the preferred test. We reviewed vitamin B12 assays on 1599 consecutive patients and prospectively studied all patients with low serum B12 levels (n = 75) and a random sample of patients with normal levels (n = 68). Of 96 evaluable patients, 7 had clinical deficiency. All 7 deficient patients had urinary methylmalonic acid levels greater than 5 micrograms/mg creatine (sensitivity, 100%; confidence interval, 65% to 100%). Of the 89 patients who were not clinically deficient, 88 had urinary methylmalonic acid levels less than or equal to 5 micrograms/mg creatinine (specificity, 99%). The overall test accuracy in this population was 99%. If the high sensitivity and specificity of the gas chromatography-mass spectrometry assay for urinary methylmalonic acid is supported by other clinical studies, the methylmalonic acid assay may become the reference standard for the diagnosis of vitamin B12 deficiency.

Matchar, D.B.; Feussner, J.R.; Millington, D.S.; Wilkinson, R.H. Jr.; Watson, D.J.; Gale, D.

1987-05-01

200

The Status of Vitamin B12 and Folate among Chinese Women: A Population-Based Cross-Sectional Study in Northwest China  

PubMed Central

Objective To assess the status of the vitamin B12 and folate of Chinese women living in northwest China. Methods A population-based cross-sectional study was conducted in 2008 among Chinese women aged 10–49 years living in Shaanxi province of northwest China. A stratified multistage random sampling method was adopted to obtain a sample of 1170 women. The women were interviewed for collection of their background information and their plasma vitamin B12 and folate were measured with the immunoassay method. The status of both vitamins was evaluated and the prevalence of deficiency was estimated. Results The median value of the women was 214.5 pg/mL for vitamin B12 and 4.6 ng/mL for folate. The urban women had a significantly higher vitamin B12 (254.1 vs. 195.9 pg/mL) but lower folate (4.4 vs. 4.7 ng/mL) than rural women. Total prevalence of deficiency was 45.5% (95% CI: 42.6%?48.4%) for vitamin B12 and 14.7% (95% CI: 12.6%?16.8%) for folate. About 36% of women presented vitamin B12 deficiency alone, 5.2% belonged to folate deficiency alone and 9.5% was combined deficiency in both vitamins. More than 25% of the women were in marginal vitamin B12 status (200–299 pg/mL) and 60% in marginal status of folate (3–6 ng/mL). About 75.2% of rural women with folate deficiency were deficient in vitamin B12 and 46% for urban women. Quantile regression model found decreasing coefficient of folate status across 73 different quantiles of vitamin B12, which indicated that the women with folate deficiency had lower vitamin B12 significantly compared with those with no deficiency. Conclusions The deficiency of vitamin B12 and folate is still prevalent among the Chinese women in northwest China. Vitamin B12 deficiency could be more serious and the improvement of poor vitamin B12 status should be invoked when practicing the supplementation of folate against the neural tube defects in northwest China. PMID:25390898

Dang, Shaonong; Yan, Hong; Zeng, Lingxia; Wang, Quanli; Li, Qiang; Xiao, Shengbin; Fan, Xiaojing

2014-01-01

201

Cell Metabolism RBP4 Disrupts Vitamin A Uptake Homeostasis  

E-print Network

Cell Metabolism Article RBP4 Disrupts Vitamin A Uptake Homeostasis in a STRA6-Deficient Animal The cellular uptake of vitamin A from its RBP4-bound circulating form (holo-RBP4) is a homeostatic process.Loss-of-function analysisinzebrafish embryos revealed that Stra6 deficiency caused vitamin A depri- vation of the developing eyes. We

Palczewski, Krzysztof

202

An appraisal of the value of vitamin B 12 in the prevention of motion sickness  

NASA Astrophysics Data System (ADS)

Unpublished reports have suggested that hydroxycobalamin (B 12, i.m.) prevents motion sickness. Some biomedical evidence supports this contention in that B 12 influences the metabolism of histidine and choline; dietary precursors to neurotransmitters with established roles in motion sickness. Susceptibility to motion sickness was evaluated after B 12 (1000 ?g, i.m.). Subjects initially completed vestibular function and motion sickness susceptibility tests to establish normal vestibular function. The experimental motion stressor was a modified coriolis sickness susceptibility test. Subjects executed standardized head movements at successively higher RPM until a malaise III endpoint was reached. Following two baseline tests with this motion stressor, subjects received a B 12 injection, a second injection two weeks later, and a final motion sickness test three weeks later. No significant differences in susceptibility were noted after B 12. Hematological parameters revealed no B 12 deficiency before injection. The possibility that patients with B 12 deficiencies are more susceptible to motion sickness cannot be ruled out.

Kohl, Randall L.; Lacey, Carol L.; Homick, Jerry L.

203

[Vitamin B12-independent strains of Methylophaga marina isolated from Red Sea algae].  

PubMed

Two strains (KM3 and KM5) of halophilic methylobacteria isolated from Red Sea algae do not require vitamin B12 for growth and can use methanol, methylamine, dimethylamine, trimethylamine, dimethyl sulfide, and fructose as sources of carbon and energy. The cells of these strains are gram-negative motile monotrichous (strain KM3) or peritrichous (strain KM5) rods. The strains are strictly aerobic and require Na+ ions but not growth factors for growth. They are oxidase- and catalase-positive and reduce nitrates to nitrites. Both strains can grow in a temperature range of 4 to 37 degrees C (with optimal growth at 29-34 degrees C), at pH between 5.5 and 8.5 (with optimal growth at pH 7.5-8.0), and in a range of salt concentrations between 0.5 and 15% NaCl (with optimal growth at 5-9% NaCl). The phospholipids of these strains are dominated by phosphatidylethanolamine and phosphatidylglycerol and also include phosphatidylcholine, phosphatidylserine, and cardiolipin. The dominant fatty acids are C(16:1omega7c) and C(16:0). The major ubiquinone is Q8. The cells accumulate ectoin, glutamate, and sucrose as intracellular osmoprotectants. The strains implement the 2-keto-3-deoxy-6-phosphogluconate-dependent variant of the ribulose monophosphate pathway. The G+C content of the DNA is 44.4-44.7 mol %. Analysis of the 16S rRNA genes showed that both strains belong to Gammaproteobacteria and have a high degree of homology (99.4%) to Methylophaga marina ATCC 35842T . Based on the data of polyphasic taxonomy, strains KM3 and KM5 are identified as new strains M. marina KM3 (VKM B-2386) and M. marina KM5 (VKM B-2387). The ability of these strains to produce auxins (indole-3-acetic acid) suggests their metabolic association with marine algae. PMID:17410879

Li, Ts D; Doronina, N V; Ivanova, E G; Trotsenko, Iu A

2007-01-01

204

Combined spectroscopic/computational studies of vitamin B12 precursors: geometric and electronic structures of cobinamides.  

PubMed

Vitamin B(12) (cyanocobalamin) and its biologically active derivatives, methylcobalamin and adenosylcobalamin, are members of the family of corrinoids, which also includes cobinamides. As biological precursors to cobalamins, cobinamides possess the same structural core, consisting of a low-spin Co(3+) ion that is ligated equatorially by the four nitrogens of a highly substituted tetrapyrrole macrocycle (the corrin ring), but differ with respect to the lower axial ligation. Specifically, cobinamides possess a water molecule instead of the nucleotide loop that coordinates axially to Co(3+)cobalamins via its dimethylbenzimidazole (DMB) base. Compared to the cobalamin species, cobinamides have proven much more difficult to study experimentally, thus far eluding characterization by X-ray crystallography. In this study, we have utilized combined quantum mechanics/molecular mechanics (QM/MM) computations to generate complete structural models of a representative set of cobinamide species with varying upper axial ligands. To validate the use of this approach, analogous QM/MM geometry optimizations were carried out on entire models of the cobalamin counterparts for which high-resolution X-ray structural data are available. The accuracy of the cobinamide structures was assessed further by comparing electronic absorption spectra computed using time-dependent density functional theory to those obtained experimentally. Collectively, the results obtained in this study indicate that the DMB ? H(2)O lower axial ligand switch primarily affects the energies of the Co 3d(z(2))-based molecular orbital (MO) and, to a lesser extent, the other Co 3d-based MOs as well as the corrin ?-based highest energy MO. Thus, while the energy of the lowest-energy electronic transition of cobalamins changes considerably as a function of the upper axial ligand, it is nearly invariant for the cobinamides. PMID:22332807

Reig, Amanda J; Conrad, Karen S; Brunold, Thomas C

2012-03-01

205

Cognitive Performance and Plasma Levels of Homocysteine, Vitamin B12, Folate and Lipids in Patients with Alzheimer Disease  

Microsoft Academic Search

Background: Conflicting results have been reported on the association of plasma total homocysteine (tHcy) and cholesterol levels in Alzheimer disease (AD). The objective of this study was to determine the relationship between cognitive performance and plasma levels of tHcy and its biological determinants folate and vitamin B12, and lipids in clinically diagnosed AD patients. Methods: A cross-sectional database review was

Ling Li; Dongfeng Cao; Renee Desmond; Atiq Rahman; James J. Lah; Allan I. Levey; Edward Zamrini

2008-01-01

206

Homocysteine and vitamin B12 status and iron deficiency anemia in female university students from Gaza Strip, Palestine  

PubMed Central

Objective Nutritional deficiencies are very significant to the overall health of humans at all ages and for both genders, yet in infants, children and women of childbearing age these deficiencies can seriously affect growth and development. The present work is aimed to assess homocysteine and vitamin B12 status in females with iron deficiency anemia from the Gaza Strip. Methods Venous blood samples were randomly collected from 240 female university students (18–22 years old) and parameters of the complete blood count, serum ferritin, homocysteine and vitamin B12 were measured. Statistical analysis included the t-test and analysis of variance (ANOVA) using the IBM SPSS software (version 18). Statistical significance was set for p-values <0.05. Results The results revealed that 20.4% of the students have iron deficiency anemia. The mean serum vitamin B12 level in females with iron deficiency anemia (212.9 ± 62.8 pg/mL) was significantly lower than in normal controls (286.9 ± 57.1 pg/mL) and subjects with microcytic anemia and normal ferritin (256.7 ± 71.1 pg/mL). Significantly higher serum homocysteine levels were reported in the iron deficiency anemia group (27.0 ± 4.6 ?mol/L) compared to normal controls (15.5 ± 2.9 ?mol/L) and in subjects with microcytic anemia and normal ferritin (18.1 ± 2.7 ?mol/L). Statistically significant negative correlations were reported for serum homocysteine with serum ferritin, vitamin B12, hemoglobin, and hematocrit levels. Conclusion Important associations were found between serum homocysteine and markers of iron deficiency. Monitoring homocysteine levels might be essential to understand the development of different clinical conditions including anemia. It seems necessary to conduct prospective trials to determine whether treating anemia ameliorates homocysteine levels. PMID:25031061

Sirdah, Mahmoud Mohammed; Yassin, Maged M.; El Shekhi, Sabreen; Lubbad, Abdel Monem

2014-01-01

207

Plasma 25-hydroxyvitamin D3, folate and vitamin B12 biomarkers among international colorectal cancer patients: a pilot study.  

PubMed

Vitamin D and folate are associated with decreased colorectal cancer risk and their association with colorectal cancer prognosis is under investigation. We assessed the levels of plasma 25-hydroxyvitamin D3 (25(OH)D3), folate and vitamin B12 in an international pilot study in order to determine variability of these biomarkers based on geographical location. Plasma 25(OH)D3, folate and vitamin B12 concentrations were measured in 149 invasive, newly diagnosed colorectal cancer cases from Heidelberg (Germany), Seattle (WA, USA), and Tampa (FL, USA) and in ninety-one age- and sex-matched controls. Their associations with potential predictors were assessed using multivariate linear regression analyses. Plasma 25(OH)D3, folate and vitamin B12 concentrations differed by location. Other predictors were season for 25(OH)D3 and tumour stage (vitamin B12). Season-corrected average 25(OH)D3 concentrations were higher in Heidelberg (31·7 ng/ml; range 11·0-83·0 ng/ml) than in Seattle (23·3 ng/ml; range 4·0-80·0 ng/ml) and Tampa (21·1 ng/ml; range 4·6-51·6 ng/ml). In Heidelberg, a strong seasonal variation was observed. Folate (11·1 ng/ml) and vitamin B12 (395 pg/ml) concentrations in Heidelberg were lower than those in Seattle (25·3 ng/ml and 740 pg/ml, respectively) and Tampa (23·8 ng/ml and 522 pg/ml, respectively). Differences in plasma 25(OH)D3 and folate concentrations between Heidelberg and the US sites were observed, probably reflecting variation in outdoor activities and sun-avoidance behaviour during summer as well as in folic acid fortification and supplement use. Intra-site differences at each study location were greater than between-location variability, suggesting that individual health behaviours play a significant role. Nevertheless, the intra-site differences we observed may be due to chance because of the limited sample size. Our pilot study illustrates the value of an international cohort in studying colorectal cancer prognosis to discern geographical differences in a broad range of exposures. PMID:25191595

Ulrich, Cornelia M; Toriola, Adetunji T; Siegel, Erin M; Brenner, Hermann; Chang-Claude, Jenny; Abbenhardt, Clare; Kotzmann, Jana; Song, Xiaoling; Owen, Robert W; Hoffmeister, Michael; Becher, Heiko; Shibata, David; Vickers, Kathy; Rush, Shannon K; Makar, Karen; Würtele, Gerd; Haubner, Roswitha; Sellers, Thomas A; Grady, William

2013-01-01

208

DNA chain elongation rates in marrow cells from vitamin B12-deficient patients and methotrexate-treated mice.  

PubMed

The DNA synthesized by marrow cells from patients with vitamin B12 deficiency and mice previously given methotrexate (MTX), has been investigated. Suspensions of bone marrow cells were pulse-labelled with [methyl-3H]thymidine or deoxy [5-3H]cytidine for 30 s and the radioactivity in the DNA was chased thereafter in the presence of 10 microM non-radioactive nucleoside for periods up to 60 min. The rates of elongation of new daughter strands were then assessed by hydroxyapatite chromatography of alkali-denatured DNA samples. No significant differences were found between the average rates of elongation of daughter strands from control marrow cells on the one hand and the vitamin B12-deficient or the methotrexate-affected cells on the other. This is to be contrasted with the results of previous studies which have shown a retardation in the rates of movement of replication forks in stimulated, cultured lymphocytes obtained from vitamin B12- or folate-deficient patients. PMID:6277361

Bond, A N; Harris, G; Wickramasinghe, S N

1982-02-01

209

Association between dietary intake of folate, vitamin B6, B12 & MTHFR, MTR Genotype and breast cancer risk  

PubMed Central

Objective: we conducted a case-control study to investigate the association between dietary folate, vitamin B6 and vitamin B12 intake, MTHFR and MTR genotype, and breast cancer risk. Methods: Genotyping for MTHFR C677T and A1298C and MTR A2756G polymorphisms were performed using polymerase chain reaction-restriction fragment length polymorphism analysis (PCR-RFLP) method. The intake of folate, vitamin B6 and vitamin B12 were calculated by each food item from questionnaire. Results: Subjects with breast cancer tended to have more first-degree relatives (?2=30.77, P<0.001) and have high intake of folate (t=2.42, P=0.008) and Vitamin B6 (t=2.94, P=0.002). Compared to the reference group, women with MTHFR 677 TT genotype and T allele had a significantly increased risk of breast cancer, with ORs (95%CI) of 1.8(1.08-2.27) and 1.39(1.02-1.92), respectively. For those who had folate intake?450 ug/day, MTHFR 667TT genotype was associated with a higher risk of breast cancer (OR=2.45, 95% CI=1.09-5.82, P=0.02). Similarly, subjects with Vitamin B6 intake?0.84 mg/day and MTHFR 667T allele genotype was correlated with a marginally increased risk of breast cancer. A significant interaction was observed between MTHFR C667T polymorphism and folate intake on the risk of breast cancer (P for interaction was 0.025). Conclusion: This case-control study found a significant association between MTHFR C667T polymorphism, folate intake and vitamin B6 and breast cancer risk, and a significant interaction was observed between MTHFR C667T polymorphism and folate intake on the risk of breast cancer. PMID:24639841

Weiwei, Zheng; Liping, Chen; Dequan, Li

2014-01-01

210

Vitamin B12 and pteroylglutamic acid studies in the domestic fowl  

E-print Network

? ration of vitamin B, p on the B-. P content of egg yolks........................... 5 Chapter 3. Factors affecting the in vitro conversion of folic acid (PGA) to the citrovorum factor (CF)............................ 29 Chapter 4. Effect of vitamin... of vitamin B^2 several workers (Doctor et al., '53; Drysdale et al., *51) have reported that the vitamin is implicated in utilization of pteroylglutamic acid (folic acid). Soon after the discovery of the citrovorum factor (OF, folinic acid...

Reid, Bobby Leroy

2013-10-04

211

Vitamin B-12 status is associated with socioeconomic level and adherence to an animal food dietary pattern in Colombian school children.  

PubMed

Vitamin B-12 is related to neurocognitive function in school-age children, yet sociodemographic and dietary correlates of vitamin B-12 status in this age group are not well characterized. The prevalences of vitamin B-12 or folate deficiencies in Colombia are unknown. We conducted a cross-sectional study in a representative sample of 2800 low- and middle-income children aged 5-12 y from Bogotá's public schools. Plasma vitamin B-12 and erythrocyte folate concentrations (mean +/- SD) were 327 +/- 106 pmol/L and 858 +/- 256 nmol/L, respectively. The prevalence of vitamin B-12 deficiency (<148 pmol/L) was 1.6% and the prevalence of marginal status (148-221 pmol/L) was 15.0%. Only 2 children had folate deficiency (<305 nmol/L). In multivariate analysis, mean vitamin B-12 concentrations significantly decreased with age and were 15 pmol/L higher in girls than boys (95%CI = 8, 23). Vitamin B-12 was inversely related to the mother's parity and positively associated with the amount of money spent on food per person per day at home and the household's neighborhood socioeconomic status (SES) classification. Folate concentrations were lower in girls than in boys and significantly increased with the household's SES. We identified 4 dietary patterns with principal components analysis of a FFQ in a random subsample (n = 972). Plasma vitamin B-12 was strongly, positively associated with a pattern that included frequent intake of beef, chicken, and dairy products in a dose-response manner (P-trend, adjusted, = 0.008). Low vitamin B-12 status is not negligible in Colombian school children and is associated with poverty and marginal intake of animal food sources. PMID:18567766

Villamor, Eduardo; Mora-Plazas, Mercedes; Forero, Yibby; Lopez-Arana, Sandra; Baylin, Ana

2008-07-01

212

Vitamin K uptake in hepatocytes and hepatoma cells.  

PubMed

Hepatocellular carcinoma (HCC) or hepatoma cells have impaired ability to perform vitamin K-dependent carboxylation reactions. Vitamin K can also inhibit growth of HCC cells in vitro. Both carboxylation and growth inhibition are vitamin K dose dependent. We used rat hepatocytes, a vitamin K-growth sensitive (MH7777) and a vitamin K-growth resistant (H4IIE) rat hepatoma cell line to examine vitamin K uptake and vitamin K-mediated microsomal carboxylation. We found that vitamin K is taken up by normal rat hepatocytes against a saturable concentration gradient. The relative rates of uptake by rat hepatocytes and the two rat cell lines MH7777 and H4IIE correlated with their sensitivity to vitamin K-mediated cell growth inhibition. Pooled hepatocytes from liver nodules from rats treated with the hepatocarcinogen diethylnitrosamine (DEN) also had a reduced rate of vitamin K uptake. However, using a cell-free system, microsomes from both normal rat hepatocytes and the two rat hepatoma cell lines had a similar ability to support carboxylation mediated by exogenously added vitamin K. The results support the hypothesis that different sensitivity of hepatoma cells to vitamin K may be due to differences in vitamin K uptake and may be unrelated to the actions of vitamin K on carboxylation. PMID:12002802

Li, Zhong-Qian; He, Feng-Yun; Stehle, Christine J; Wang, Ziqiu; Kar, Siddhartha; Finn, Frances M; Carr, Brian I

2002-03-22

213

Methionine, folic acid and vitamin B12 in growing-finishing pigs: impact on growth performance and meat quality.  

PubMed

Growth performance, metabolic variables, and meat quality were measured in 78 growing-finishing pigs using supplements of 0 (C), or 0.2% of DL-methionine (M), and three combinations of folic acid [mg/kg] and cyanocobalamin [microg/kg], respectively 0 and 0 (V0), 10 and 25 (V1), and 10 and 150 (V2) in a 2 x 3 factorial arrangement. Feed conversion was lower (p = 0.05) in M than in C pigs during the growing period (0-4 weeks). Both V1 and V2 treatments increased plasma vitamin B12 (p < 0.01) and decreased plasma homocysteine (p < 0.01). Plasma 5-methyl-tetrahydrofolates were the lowest, highest and intermediate in V0, V1 and V2 pigs (p < 0.04), respectively. In V2 meat, folates were 32% higher, vitamin B12, 55% higher and homocysteine, 28% lower than in V0 (p < 0.01). Oxidative stability of the fresh meat was similar among treatments during a storage period of 42 days. Therefore, methionine supplements improved growth performance during the growing period. Vitamin supplements interacted with the methionine cycle pathway, increased vitamin content of pork meat but did not improve oxidative stability of the fresh meat during storage. PMID:18610535

Giguére, Alain; Girard, Christiane L; Matte, J Jacques

2008-06-01

214

Recovery from vitamin B-12-induced unbalanced growth. The shortened cell cycle and the deoxyribonucleoside triphosphate pools.  

PubMed

The deoxyribonucleoside triphosphate pools are undetectable in vitamin B-12-deficient cells of Euglena gracillis, but appear rapidly after the replenishment with the vitamin. They reach a maximum size that is about 6 times that of normal exponentially growing cells, but decrease to almost zero as the cells divide. The pools expand again during the post-replenishment shortened cell cycle. However, the expansion takes place during rather than before the resumption of DNA synthesis. The maximum sizes reached are still larger than in normal cells. By using the protein-synthesis inhibitor cycloheximide and determining the pool size, we found that vitamin-deficient cells apparently accumulate a large amount of ribonucleoside triphosphate reductase apoenzyme, which lacks the vitamin B12 coenzyme. We showed that the production of the deoxyribonucleoside triphosphates is not closely coupled to DNA synthesis under our experimental conditions, and that the concentration of the deoxyribonucleoside triphosphate pools per unit of DNA synthesized is almost constant for all stages of growth examined. PMID:417723

Goetz, G H; Carell, E F

1978-03-15

215

Ultrafast infrared spectral fingerprints of vitamin B12 and related cobalamins.  

PubMed

Vitamin B(12) (cyanocobalamin, CNCbl) and its derivatives are structurally complex and functionally diverse biomolecules. The excited state and radical pair reaction dynamics that follow their photoexcitation have been previously studied in detail using UV-visible techniques. Similar time-resolved infrared (TRIR) data are limited, however. Herein we present TRIR difference spectra in the 1300-1700 cm(-1) region between 2 ps and 2 ns for adenosylcobalamin (AdoCbl), methylcobalamin (MeCbl), CNCbl, and hydroxocobalamin (OHCbl). The spectral profiles of all four cobalamins are complex, with broad similarities that suggest the vibrational excited states are related, but with a number of identifiable variations. The majority of the signals from AdoCbl and MeCbl decay with kinetics similar to those reported in the literature from UV-visible studies. However, there are regions of rapid (<10 ps) vibrational relaxation (peak shifts to higher frequencies from 1551, 1442, and 1337 cm(-1)) that are more pronounced in AdoCbl than in MeCbl. The AdoCbl data also exhibit more substantial changes in the amide I region and a number of more gradual peak shifts elsewhere (e.g., from 1549 to 1563 cm(-1)), which are not apparent in the MeCbl data. We attribute these differences to interactions between the bulky adenosyl and the corrin ring after photoexcitation and during radical pair recombination, respectively. Although spectrally similar to the initial excited state, the long-lived metal-to-ligand charge transfer state of MeCbl is clearly resolved in the kinetic analysis. The excited states of CNCbl and OHCbl relax to the ground state within 40 ps with few significant peak shifts, suggesting little or no homolysis of the bond between the Co and the upper axial ligand. Difference spectra from density functional theory calculations (where spectra from simplified cobalamins with an upper axial methyl were subtracted from those without) show qualitative agreement with the experimental data. They imply the excited state intermediates in the TRIR difference spectra resemble the dissociated states vibrationally (the cobalamin with the upper axial ligand missing) relative to the ground state with a methyl in this position. They also indicate that most of the TRIR signals arise from vibrations involving some degree of motion in the corrin ring. Such coupling of motions throughout the ring makes specific peak assignments neither trivial nor always meaningful, suggesting our data should be regarded as IR spectral fingerprints. PMID:22612868

Jones, Alex R; Russell, Henry J; Greetham, Gregory M; Towrie, Michael; Hay, Sam; Scrutton, Nigel S

2012-06-14

216

Journal of General Microbiology (1990), 136, 529-533. Printed in Great Britain 529 Localization of vitamin Blzbinding in Euglenagradis  

E-print Network

of vitamin Blzbinding in Euglenagradis MARIOHOUDEand FATHEYSARHAN" DPpartement des Sciences Biologiques to determine the location of vitamin B12binding sites in Eugfenu grucifis.Using uptake measurements the majority of B12binding sites. The apparentdistribution of vitamin bindingsitesdiffered

Sarhan, Fathey

217

Ultra-high performance liquid chromatographic and mass spectrometric analysis of active vitamin B12 in cells of Propionibacterium and fermented cereal matrices.  

PubMed

A sensitive and selective method is needed to analyse in situ produced vitamin B12 in plant-based materials, potential new dietary sources of vitamin B12. A UHPLC/UV method was developed and validated for the determination of human active vitamin B12 in cell extracts of Propionibacterium freudenreichii subsp. shermanii and after immunoaffinity purification in extracts of cereal matrices fermented by P. freudenreichii. An Acquity HSS T3 C18 column resulted in a baseline separation, a calibration curve of excellent linearity and a low limit of detection (0.075 ng/5 ?L injection). As confirmed by UHPLC-MS, the active vitamin B12 could be separated from pseudovitamin B12. The recovery of vitamin B12 from purified spiked cereal matrices was good (>90%; RSD<5%). A nutritionally relevant amount of active vitamin B12 was produced by P. freudenreichii in cereal malt matrices (up to 1.9 ?g/100 g) in 24h at 28 °C. PMID:25053103

Chamlagain, Bhawani; Edelmann, Minnamari; Kariluoto, Susanna; Ollilainen, Velimatti; Piironen, Vieno

2015-01-01

218

Antimutagenic evaluation of vitamins B1, B6 and B12 in vitro and in vivo, with the Ames test.  

PubMed

The aim of this work is to evaluate vitamins B antimutagenic effect against alkylatings methyl-N-nitro-N-nitrosoguanidine (MNNG), ethyl-N-nitro-N'- nitrosoguanidine (ENNG), frameshift mutagens 2-aminoanthracene (2AA) and 2-acetyl-amino-fluorene (2AF) and ROS-generating antibiotics norfloxacin (NOR) and nalidixic acid (NLX), using the in vitro Ames test. In vivo antimutagenesis studies were performed against urinary mutagens induced by NOR (70 mg/kg) or NLX (100 mg/kg) in CD1 mice. Vitamin B1 was antimutagenic against alkylatings MNNG (P<0.05) or ENNG (P<0.001). In fact as per the results observed during the current study, none of the vitamins reduced mutagenesis caused by frameshift mutagens. All of them reduced mutagenesis of NOR or NLX (P<0.001). In vivo studies showed that vitamins B1 and B6 (10 or 100 mg/kg) reduced urinary mutagens from NOR (P<0.001) or NLX (P<0.02) either free or ?-glucoronidase-conjugates. None of the studied samples were toxic for the employed antimutagenic system. Vitamin B12 (4 mg/kg) reduced urinary mutagens of NOR or NLX (P<0.02). Vitamins B inhibited DNA mutations induced by ROS generated by NLX or NOR, both in vitro and in vivo. Vitamin B1is antimutagenic against mutations induced by the alkylating MNNG or ENNG. Based on the observations, employment of vitamins B in vivo can be a promising alternative to reduce genotoxic risk exposure to ROS. PMID:23201371

Arriaga-Alba, Myriam; Ruiz-Pérez, Nancy Janett; Sánchez-Navarrete, Jaime; de Angel, Beatriz López; Flores-Lozada, Jorge; Blasco, José Luis

2013-03-01

219

Long term treatment with metformin in patients with type 2 diabetes and risk of vitamin B12 deficiency: randomised placebo controlled trial  

Microsoft Academic Search

Objectives To study the effects of metformin on the incidence of vitamin B-12 deficiency (<150 pmol\\/l), low concentrations of vitamin B-12 (150-220 pmol\\/l), and folate and homocysteine concentrations in patients with type 2 diabetes receiving treatment with insulin.Design Multicentre randomised placebo controlled trial.Setting Outpatient clinics of three non-academic hospitals in the Netherlands.Participants 390 patients with type 2 diabetes receiving treatment

Jolien de Jager; Adriaan Kooy; Philippe Lehert; Michiel G Wulffelé; Jan van der Kolk; Daniël Bets; Joop Verburg; Ab J M Donker; Coen D A Stehouwer

2010-01-01

220

Determination of Vitamin B 12 in food products and in premixes by reversed-phase high performance liquid chromatography and immunoaffinity extraction  

Microsoft Academic Search

A new, faster and simple method to quantify Vitamin B12, both in foods and in premixes, by reversed-phase liquid chromatography with UV detection has been developed. Vitamin B12 was extracted from food products with 50mM sodium acetate buffer pH 4.0 (at 100°C for 35min) in the presence of sodium cyanide, followed by a purification step on an immunoaffinity column prior

O. Heudi; T. Kilinç; P. Fontannaz; E. Marley

2006-01-01

221

Serum homocysteine, folate and vitamin B 12 in patients with Paget’s disease of bone: the effect of zoledronic acid  

Microsoft Academic Search

High serum homocysteine (HCY) and indirectly deficiency of folate and\\/or vitamin B12 stimulate bone resorption and adversely affect collagen cross-linking. The aim of this study was the evaluation of serum\\u000a levels of HCY, folate and vitamin B12 in patients with Paget’s disease of bone (PDB) and the effect of zoledronic acid (ZOL) on their serum levels. Nine consecutive\\u000a patients with

Stergios A. PolyzosAthanasios; Athanasios D. Anastasilakis; Zoe Efstathiadou; Ioannis Litsas; Marina Kita; Athanasios Panagiotou; Athanasios Papatheodorou; Georgios Arsos; Efstratios Moralidis; Georgios Barmpalios; Efthimia Zafeiriadou; Efthimia Triantafillidou; Eleni Makrigiannaki; Evangelos Terpos

2010-01-01

222

Socioeconomic factors are associated with folate and vitamin B12 intakes and related biomarkers concentrations in European adolescents: the Healthy Lifestyle in Europe by Nutrition in Adolescence study.  

PubMed

Because socioeconomic factors (SEFs) may influence dietary quality and vitamin intakes, this study aimed to examine associations between socioeconomic factors and folate and vitamin B12 intakes as well as their related biomarkers in the Healthy Lifestyle in Europe by Nutrition in Adolescence study. Vitamin intakes were obtained from two 24-hour recalls in 2253 participants (47% males). Vitamin B biomarkers were assessed in a subsample of 977 participants (46% males). Socioeconomic factors were assessed by questionnaire, and 1-way analysis of covariance and linear regression analysis were applied. For males and females, mean intakes of folate were 211.19 and 177.18 ?g/d, and for vitamin B12, 5.98 and 4.54 ?g/d, respectively. Levels of plasma folate, red blood cell folate, serum B12, and holotranscobalamin were 18.74, 807.19, 330.64, and 63.04 nmol/L in males, respectively, and 19.13, 770.16, 377.9, and 65.63 nmol/L in females, respectively. Lower folate intakes were associated with several SEFs, including maternal and paternal education in both sexes. Regarding folate biomarkers, lower plasma folate intakes were associated with single/shared care in males and with lower paternal occupation in females. Lower vitamin B12 intakes were associated with almost all the studied SEFs, except paternal occupation in both sexes. In females, when considering vitamin B12 biomarkers, lower plasma vitamin B12 was associated with lower maternal education and occupation, and lower holotranscobalamin was associated with lower maternal education and lower paternal occupation. In conclusion, from the set of socioeconomic determinants studied in a sample of European adolescents, maternal education and paternal occupation were more consistently associated with folate and vitamin B12 intakes and biomarkers concentrations. PMID:24655486

Iglesia, Iris; Mouratidou, Theodora; González-Gross, Marcela; Novakovic, Romana; Breidenassel, Christina; Jiménez-Pavón, David; Huybrechts, Inge; De Henauw, Stefaan; Geelen, Anouk; Gottrand, Frédéric; Kafatos, Anthony; Mistura, Lorenza; de Heredia, Fátima Pérez; Widhalm, Kurt; Manios, Yanis; Molnar, Denes; Stehle, Peter; Gurinovic, Mirjana; Cavelaars, Adrienne E J M; Van't Veer, Pieter; Moreno, Luis A

2014-03-01

223

Effect of vitamin B12 on cleft palate induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin and dexamethasone in mice*  

PubMed Central

The purpose of this study was to investigate the effect of vitamin B12 on palatal development by co-administration of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and dexamethasone (DEX). We examined the morphological and histological features of the palatal shelf and expression levels of key signaling molecules (transforming growth factor-?3 (TGF-?3) and TGF-? type I receptor (activin receptor-like kinase 5, ALK5)) during palatogenesis among a control group (Group A), TCDD+DEX exposed group (Group B), and TCDD+DEX+vitamin B12 exposed group (Group C). While we failed to find that vitamin B12 decreased the incidence of cleft palate induced by TCDD+DEX treatment, the expression levels of key signaling molecules (TGF-?3 and ALK5) during palatogenesis were significantly modulated. In TCDD+DEX exposed and TCDD+DEX+vitamin B12 exposed groups, palatal shelves could not contact in the midline due to their small sizes. Our results suggest that vitamin B12 may inhibit the expression of some cleft palate inducers such as TGF-?3 and ALK5 in DEX+TCDD exposed mice, which may be beneficial against palatogenesis to some degree, even though we were unable to observe a protective role of vitamin B12 in morphological and histological alterations of palatal shelves induced by DEX and TCDD. PMID:24599693

Zhao, Shu-fan; Chai, Mao-zhou; Wu, Min; He, Yong-hong; Meng, Tian; Shi, Bing

2014-01-01

224

An effective and simplified pH-stat control strategy for the industrial fermentation of vitamin B(12) by Pseudomonas denitrificans.  

PubMed

In order to improve the productivity of vitamin B(12) by Pseudomonas denitrificans carried out in a 120-m(3) fermenter, the effect of pH on vitamin B(12) biosynthesis was investigated. Results obtained from shake flask experiments showed that the feeding of carbon source (beet molasses or glucose) and methyl-group donor (betaine or choline chloride) significantly influenced the pH and the biosynthesis of vitamin B(12). In contrast to beet molasses or choline chloride, using glucose as a feed medium and betaine as a methyl-group donor, pH could be maintained at a stable range. As a result, higher vitamin B(12) production was achieved. Accordingly, an effective and simplified pH-stat control strategy was established for the fermentation of vitamin B(12) in a 120-m(3) industrial fermenter. When the new pH control strategy was applied, pH was stably kept in the range of 7.15-7.30 during fermentation. Thus, 214.3 microg/mL of vitamin B(12) was achieved. PMID:18320234

Li, Kun-Tai; Liu, Dong-Hong; Chu, Ju; Wang, Yong-Hong; Zhuang, Ying-Ping; Zhang, Si-Liang

2008-10-01

225

Pseudo-HELLP syndrome par carence en folates et/ou en vitamine B12: ? propos d'un cas  

PubMed Central

Plusieurs pathologies médicales peuvent interférer avec la grossesse et mimer le tableau biologique de HELLP syndrome. L’évolution naturelle de ce syndrome est d'une particulière gravité pour la mère et le fœtus, il convient d’éliminer rapidement les autres diagnostics afin d’éviter une extraction fœtale prématurée injustifiée. Nous rapportons le cas d'une parturiente qui s'est présentée avec un tableau évocateur d'un HELLP syndrome, rapporté finalement à une carence en folates et en vitamine B12.

Benali, Mechaal; Bouassida, Mahdi; Dhouib, Firas; Bouzeidi, Kaled

2014-01-01

226

The causal roles of vitamin B12 and transcobalamin in prostate cancer: can Mendelian randomization analysis provide definitive answers?  

PubMed Central

Circulating vitamin B12 (cobalamin/B12) and total transcobalamin (tTC) have been associated with increased and reduced risk, respectively, of prostate cancer. Mendelian randomization has the potential to determine whether these are causal associations. We estimated associations of single nucleotide polymorphisms in B12-related genes (MTR, MTRR, FUT2, TCN2, TCN1, CUBN, and MUT) with plasma concentrations of B12, tTC, holo-transcobalamin, holo-haptocorrin, folate, and homocysteine and with prostate cancer risk in a case-control study (913 cases, 895 controls) nested within the UK-wide population-based ProtecT study of prostate cancer in men age 45-69 years. Instrumental variable (IV) analysis was used to estimate odds ratios for effects of B12 and tTC on prostate cancer. We observed that B12 was lower in men with FUT2 204G>A (rs492602), CUBN 758C>T (rs1801222) and MUT 1595G>A (rs1141321) alleles (Ptrend<0.001); tTC was lower in men with the TCN2 776C>G (rs1801198) allele (Ptrend<0.001). FUT2 204G>A and CUBN 758C>T were selected as instruments for B12; TCN2 776C>G for tTC. Conventional and IV estimates for the association of loge(B12) with prostate cancer were: OR=1.17 (95% CI 0.90-1.51), P=0.2 and OR=0.60 (0.16-2.15), P=0.4, respectively. Conventional and IV estimates for the association of loge(tTC) with prostate cancer were: OR=0.81 (0.54-1.20), P=0.3 and OR=0.41 (0.13-1.32), P=0.1, respectively. Confidence intervals around the IV estimates in our study were too wide to allow robust inference. Sample size estimates based on our data indicated that Mendelian randomization in this context requires much larger studies or multiple genetic variants that explain all of the variance in the intermediate phenotype. PMID:22199995

Collin, Simon M; Metcalfe, Chris; Palmer, Tom M; Refsum, Helga; Lewis, Sarah J; Smith, George Davey; Cox, Angela; Davis, Michael; Marsden, Gemma; Johnston, Carole; Lane, J Athene; Donovan, Jenny L; Neal, David E; Hamdy, Freddie C; Smith, A David; Martin, Richard M

2011-01-01

227

Prevalence of Vitamin B12 deficiency in patients of type 2 diabetes mellitus on metformin: A case control study from Pakistan  

PubMed Central

Introduction Diabetes Mellitus is the most common endocrine disorder and metformin is the most commonly prescribed oral hypoglycemic agent. Metformin is well known to cause viamin B12 deficiency due to effect on calcium-dependent membrane action in the terminal ileum leading to malabsorption of vitamin B12. The purpose of this study is to determine prevalence and associations of Vitamin B12 deficiency in patients of type 2 diabetes mellitus treated with metformin. Methods This case control study was carried out in department of medicine, Combined Military Hospital, Kharian from 1st Jan 2012 to 30 december 2012. We enrolled 114 outdoor patients of type 2 diabetes mellitus currently on metformin for atleast 12 months, by consecutive sampling, and 105 age and sex matched patients taken as control. Patients with vitamin B12 levels of less than 150 pg/ml were said to be B12 deficient. The results were analyzed on SPSS version 16. Results Serum B12 levels were low in 35 patients (31%) on metformin as compared to only 9 patients (8.6%) among controls,(p value 0.002). Mean B12 levels were significantly low in metformin group 311 pg/ml (±194.4), p value 0.03. Dose of metformin had inverse correlation with B12 levels and the difference was statistically significant with p-value < 0.001. Conclusion Our study demonstrated significantly high prevalence of vitamin B12 deficiency in patients treated with metformin with significant effect of dose and duration of metformin use on B12 levels. Physicians must recognize this important fact and screen diabetics on metformin therapy for underlying B12 deficiency. PMID:24711867

Iftikhar, Raheel; Kamran, Sultan Mehmood; Qadir, Adnan; Iqbal, Zohaib; Usman, Hassan bin

2013-01-01

228

Comparison of Reactors for Oxygen-Sensitive Reactions: Reductive Dechlorination of Chlorophenols by Vitamin B12s  

PubMed Central

Serum bottles are frequently used for studies of reductive dechlorination by vitamin B12, but reducing conditions can be maintained only for several days. This time period is inadequate for evaluating the reductive dechlorination of some slow-reacting aromatic compounds. Sealed glass ampoules maintain reducing conditions for many months, but this method has the disadvantage of disallowing subsampling of the reaction mixture. A glass serum tube was modified for these experiments which not only maintained anoxic conditions for several days but also allowed subsamples to be removed during experiments. The modification was a restriction placed in the middle of the tube by heating in a flame, creating two chambers separated by a narrow neck. The lower chamber contained the oxygen-sensitive reaction mixture. The upper chamber, sealed with a septum and screw cap, was purged with purified nitrogen or argon introduced and vented through fused silica capillaries. Reductive dechlorination of chlorophenols by vitamin B12 reduced with Ti(III) citrate was monitored in all three reactor types. Sealed ampoules maintained reducing conditions for up to 12 months. The two-chambered reactor maintained reducing conditions longer than the serum vials when frequent samples were taken. PMID:16349437

Smith, Mark H.; Woods, Sandra L.

1994-01-01

229

Recycling of vitamin B12 and NAD+ within the Pdu microcompartment of Salmonella enterica  

Microsoft Academic Search

Salmonella enterica is capable of utilizing 1,2-propanediol (1,2-PD) as a sole carbon and energy source in a coenzyme B12 (Adenosylcobalamin, AdoCbl) -dependent fashion that involves a bacterial microcompartment (MCP), the Pdu MCP. Pdu MCP is a polyhedral organelle composed entirely of protein subunits and its function is to sequester the intermediate propionaldehyde formed in the first step of 1,2-PD degradation

Shouqiang Cheng

2010-01-01

230

Higher Prevalence of Metformin-Induced Vitamin B12 Deficiency in Sulfonylurea Combination Compared with Insulin Combination in Patients with Type 2 Diabetes: A Cross-Sectional Study  

PubMed Central

Long-term and high-dose treatment with metformin is known to be associated with vitamin B12 deficiency in patients with type 2 diabetes. We investigated whether the prevalence of B12 deficiency was different in patients treated with different combination of hypoglycemic agents with metformin during the same time period. A total of 394 patients with type 2 diabetes treated with metformin and sulfonylurea (S+M group, n?=?299) or metformin and insulin (I+M group, n?=?95) were consecutively recruited. The vitamin B12 and folate levels were quantified using the chemiluminescent enzyme immunoassay. Vitamin B12 deficiency was defined as vitamin B12?300 pg/mL without folate deficiency (folate>4 ng/mL). The mean age of and duration of diabetes in the subjects were 59.4±10.5 years and 12.2±6.7 years, respectively. The mean vitamin B12 level of the total population was 638.0±279.6 pg/mL. The mean serum B12 levels were significantly lower in the S+M group compared with the I+M group (600.0±266.5 vs. 757.7±287.6 pg/mL, P<0.001). The prevalence of vitamin B12 deficiency in the metformin-treated patients was significantly higher in the S+M group compared with the I+M group (17.4% vs. 4.2%, P?=?0.001). After adjustment for various factors, such as age, sex, diabetic duration, duration or daily dose of metformin, diabetic complications, and presence of anemia, sulfonylurea use was a significant independent risk factor for B12 deficiency (OR?=?4.74, 95% CI 1.41–15.99, P?=?0.012). In conclusion, our study demonstrated that patients with type 2 diabetes who were treated with metformin combined with sulfonylurea require clinical attention for vitamin B12 deficiency and regular monitoring of their vitamin B12 levels. PMID:25299054

Kang, Donghoon; Yun, Jae-Seung; Ko, Sun-Hye; Lim, Tae-Seok; Ahn, Yu-Bae; Park, Yong-Moon; Ko, Seung-Hyun

2014-01-01

231

Higher prevalence of metformin-induced vitamin B12 deficiency in sulfonylurea combination compared with insulin combination in patients with type 2 diabetes: a cross-sectional study.  

PubMed

Long-term and high-dose treatment with metformin is known to be associated with vitamin B12 deficiency in patients with type 2 diabetes. We investigated whether the prevalence of B12 deficiency was different in patients treated with different combination of hypoglycemic agents with metformin during the same time period. A total of 394 patients with type 2 diabetes treated with metformin and sulfonylurea (S+M group, n?=?299) or metformin and insulin (I+M group, n?=?95) were consecutively recruited. The vitamin B12 and folate levels were quantified using the chemiluminescent enzyme immunoassay. Vitamin B12 deficiency was defined as vitamin B12?300 pg/mL without folate deficiency (folate>4 ng/mL). The mean age of and duration of diabetes in the subjects were 59.4±10.5 years and 12.2±6.7 years, respectively. The mean vitamin B12 level of the total population was 638.0±279.6 pg/mL. The mean serum B12 levels were significantly lower in the S+M group compared with the I+M group (600.0±266.5 vs. 757.7±287.6 pg/mL, P<0.001). The prevalence of vitamin B12 deficiency in the metformin-treated patients was significantly higher in the S+M group compared with the I+M group (17.4% vs. 4.2%, P?=?0.001). After adjustment for various factors, such as age, sex, diabetic duration, duration or daily dose of metformin, diabetic complications, and presence of anemia, sulfonylurea use was a significant independent risk factor for B12 deficiency (OR?=?4.74, 95% CI 1.41-15.99, P?=?0.012). In conclusion, our study demonstrated that patients with type 2 diabetes who were treated with metformin combined with sulfonylurea require clinical attention for vitamin B12 deficiency and regular monitoring of their vitamin B12 levels. PMID:25299054

Kang, Donghoon; Yun, Jae-Seung; Ko, Sun-Hye; Lim, Tae-Seok; Ahn, Yu-Bae; Park, Yong-Moon; Ko, Seung-Hyun

2014-01-01

232

Rapid Assessment for Coexistence of Vitamin B12 and Iron Deficiency Anemia among Adolescent Males and Females in Northern Himalayan State of India  

PubMed Central

Coexistence of folic acid and vitamin B12 deficiency has been observed among adolescents with iron deficiency anemia, but limited evidence is available from India. So, a rapid assessment was done to study the prevalence of iron, folic acid, and vitamin B12 deficiency among adolescent males and females in northern Himalayan state in India. Methods. Total 885 (female: 60.9%) adolescents (11 to 19 completed years) were surveyed from 30-cluster village from two community development blocks of Himachal Pradesh. Serum ferritin, folic acid, and vitamin B12 were estimated among randomly selected 100 male and 100 female adolescents. Results. Under-nutrition (BMI < 18.5?kg/m2) was observed among 68.9% of adolescents (male: 67.1%; female: 70.7; P = 0.29). Anemia was observed to be prevalent among 87.2% males and 96.7% females (P = 0.00). Mild form of anemia was observed to be the most common (53.9%) form followed by moderate (29.7%) anemia. Strikingly, it was found that all the adolescents were deficient in vitamin B12 and none of the adolescents was observed to be deficient in folic acid. Conclusion. Among both male and female adolescents anemia with vitamin B12 deficiency was observed to be a significant public health problem. Folic acid deficiency was not observed as a problem among surveyed adolescents. PMID:23970962

Bhardwaj, Ashok; Kumar, Dinesh; Raina, Sunil Kumar; Bansal, Pardeep; Bhushan, Satya; Chander, Vishav

2013-01-01

233

Vitamins  

MedlinePLUS

... grains help your body make energy from food. Vitamins Hang Out in Water and Fat There are ... acid, B12 (cobalamine), biotin, and pantothenic acid. Continue Vitamins Feed Your Needs Your body is one powerful ...

234

Towards a cell factory for vitamin B12 production in Bacillus megaterium: bypassing of the cobalamin riboswitch control elements.  

PubMed

Bacillus megaterium is a bacterium that has been used in the past for the industrial production of vitamin B12 (cobalamin), the anti-pernicious anaemia factor. Cobalamin is a modified tetrapyrrole with a cobalt ion coordinated within its macrocycle. More recently, B. megaterium has been developed as a host for the high-yield production of recombinant proteins using a xylose inducible promoter system. Herein, we revisit cobalamin production in B. megaterium DSM319. We have investigated the importance of cobalt for optimum growth and cobalamin production. The cobaltochelatase (CbiX(L)) is encoded within a 14-gene cobalamin biosynthetic (cbi) operon, whose gene-products oversee the transformation of uroporphyrinogen III into adenosylcobyrinic acid a,c-diamide, a key precursor of cobalamin synthesis. The production of CbiX(L) in response to exogenous cobalt was monitored. The metal was found to stimulate cobalamin biosynthesis and decrease the levels of CbiX(L). From this we were able to show that the entire cbi operon is transcriptionally regulated by a B12-riboswitch, with a switch-off point at approximately 5nM cobalamin. To bypass the effects of the B12-riboswitch the cbi operon was cloned without these regulatory elements. Growth of these strains on minimal media supplemented with glycerol as a carbon source resulted in significant increases in cobalamin production (up to 200?gL(-1)). In addition, a range of partially amidated intermediates up to adenosylcobyric acid was detected. These findings outline a potential way to develop B. megaterium as a cell factory for cobalamin production using cheap raw materials. PMID:24657453

Moore, Simon J; Mayer, Matthias J; Biedendieck, Rebekka; Deery, Evelyne; Warren, Martin J

2014-12-25

235

Maternal dietary intake of folate, vitamin B12 and MTHFR 677C>T genotype: their impact on newborn's anthropometric parameters.  

PubMed

In this study, we evaluated the effects of dietary intake of vitamin B12 and folate during pregnancy and their interactions with maternal polymorphism of MTHFR (677C>T; 1298A>C) on intrauterine development. Anthropometric parameters were obtained from 231 newborns that belong to a prospective birth cohort in Morelos, Mexico. Maternal dietary intake of vitamin B12 and folate was assessed using a semi-quantitative questionnaire administered during the first and third trimesters of the pregnancy. Maternal MTHFR 677C>T and 1298 A>C genotypes were determined by PCR-RFLP. The associations between deficient dietary intake of vitamin B12 (<2.0 ?g/d) and folate (<400 ?g/d) in the first and third trimesters and maternal polymorphisms of MTHFR on anthropometric parameters at birth were estimated using a multivariate linear regression model. During pregnancy, the deficient dietary intake was roughly 60 % for folate and 19 % for vitamin B12. Allelic frequencies of 677T and 1298C were 59 and 10 %, respectively. After adjusting for confounders, deficiency in maternal dietary intake of vitamin B12 (<2.0 ?g/d) was associated with a significant reduction in length (? ~ -2.4; 95 % CI -4.3; -0.6) and length-for-age at birth (? ~ -1.2; 95 % CI -2.3; -0.1) among infants whose mothers were carriers of the 677TT genotype (p for interaction = 0.02). In contrast, no association was observed between deficiency in maternal dietary intake of folate (<400 ?g/d) and any anthropometric parameter of newborns. These results suggest that supplementation with vitamin B12 during pregnancy could have a favorable impact on intrauterine fetal development mainly in populations that are genetically susceptible. PMID:25173112

Torres-Sánchez, Luisa; López-Carrillo, Lizbeth; Blanco-Muñoz, Julia; Chen, Jia

2014-09-01

236

A Genetic Variant in Vitamin B12 Metabolic Genes That Reduces the Risk of Congenital Heart Disease in Han Chinese Populations  

PubMed Central

Background Genome-wide association studies on components of the one-carbon metabolic pathway revealed that human vitamin B12 levels could be significantly influenced by variationsinthefucosyltransferase 2 (FUT2), cubilin (CUBN), and transcobalamin-I (TCN1) genes. An altered vitamin B12 level is an important factor that disturbs the homeostasis of the folate metabolism pathway, which in turn can potentially lead to the development of congenital heart disease (CHD). Therefore, we investigated the association between the variants of vitamin B12-related genes and CHD in Han Chinese populations. Methods and Results Six variants of the vitamin B12-related genes were selected for analysis in two independent case-control studies, with a total of 868 CHD patients and 931 controls. The variant rs11254363 of the CUBN gene was associated with a decreased risk of developing CHD in both the separate and combined case-control studies. Combined samples from the two cohorts had a significant decrease in CHD risk for the G allele (OR?=?0.48, P?=?1.7×10?5) and AG+GG genotypes (OR?=?0.49, P?=?4×10?5), compared with the wild-type A allele and AA genotype, respectively. Conclusions Considering the G allele of variant rs11254363 of the CUBN gene was associated with an increased level of circulating vitamin B12. This result suggested that the carriers of the G allele would benefit from the protection offered by the high vitamin B12 concentration during critical heart development stages. This finding shed light on the unexpected role of CUBN in CHD development and highlighted the interplay of diet, genetics, and human birth defects. PMID:24533076

Wang, Feng; Peng, Qian-Qian; Hou, Jia; Sun, Shu-Na; Gui, Yong-Hao; Duan, Wen-Yuan; Qiao, Bin; Wang, Hong-Yan

2014-01-01

237

Direct exchange of vitamin B12 is demonstrated by modelling the growth dynamics of algal-bacterial cocultures.  

PubMed

The growth dynamics of populations of interacting species in the aquatic environment is of great importance, both for understanding natural ecosystems and in efforts to cultivate these organisms for industrial purposes. Here we consider a simple two-species system wherein the bacterium Mesorhizobium loti supplies vitamin B12 (cobalamin) to the freshwater green alga Lobomonas rostrata, which requires this organic micronutrient for growth. In return, the bacterium receives photosynthate from the alga. Mathematical models are developed that describe minimally the interdependence between the two organisms, and that fit the experimental observations of the consortium. These models enable us to distinguish between different mechanisms of nutrient exchange between the organisms, and provide strong evidence that, rather than undergoing simple lysis and release of nutrients into the medium, M. loti regulates the levels of cobalamin it produces, resulting in a true mutualism with L. rostrata. Over half of all microalgae are dependent on an exogenous source of cobalamin for growth, and this vitamin is synthesised only by bacteria; it is very likely that similar symbiotic interactions underpin algal productivity more generally. PMID:24522262

Grant, Matthew A A; Kazamia, Elena; Cicuta, Pietro; Smith, Alison G

2014-07-01

238

Polymorphism C776G in the transcobalamin II gene and homocysteine, folate and vitamin B 12 concentrations. Association with MTHFR C677T and A1298C and MTRR A66G polymorphisms in healthy children  

Microsoft Academic Search

One of the etiologies of hyperhomocysteinemia is decreased vitamin B12. Genetic variation in the transcobalamin II gene, the transporter of vitamin B12 to the cells, may produce altered homocysteine levels. We determined transcobalamin II C776G polymorphism, homocysteine, folate and vitamin B12 levels and analyzed the interactive effect with the methylenetetrahydrofolate reductase C677T and A1298C and methionine synthase reductase A66G polymorphisms

Ana C. M. Aléssio; Nelci F. Höehr; Lúcia H. Siqueira; Sérgio P. Bydlowski; Joyce M. Annichino-Bizzacchi

2007-01-01

239

Neuropathological and neuroprotective features of vitamin B12 on the dorsal spinal ganglion of rats after the experimental crush of sciatic nerve: an experimental study  

PubMed Central

Background Spinal motoneuron neuroprotection by vitaminB12 was previously reported; the present study was carried out to evaluate neuroprotectivity in the dorsal root ganglion sensory neuron. Methods In present study thirty-six Wister-Albino rats (aged 8–9 weeks and weighing 200–250 g) were tested. The animals were randomly divided into 6 groups which every group contained 6 rats. Group A: received normal saline (for 42 days); Group B: vitamin B12 was administered (0.5 mg/kg/day for 21 days); Group C: received vitamin B12 (1 mg/kg/day for 21days); Group D: received vitamin B12 (0.5 mg/kg/day for 42 days); Group E; received vitamin B12 (1 mg/kg/day for 42 days); Group F; received no treatment. The L5 Dorsal Root Ganglion (DRG) neurons count compared to the number of left and right neurons .Furthermore, DRG sensory neurons for regeneration were evaluated 21 or 42 days after injury (each group was analyzed by One-Way ANOVA test). Results (1): The comparison of left crushed neurons (LCN) number with right non-crushed neurons in all experimental groups (B, C, D and C), indicating a significant decline in their neurons enumeration (p<0/05). (2): The comparison of test group’s LCN with the control group’s LCN revealed a significant rise in the number of experimental group neurons (p<0/05). (3): Moreover, comparing the number of right neurons in experimental groups with the number of neurons in crushed neurons indicated that the average number of right neurons showed a significant increase in experimental groups (p<0/05). Conclusion Consequently, the probability of nerve regeneration will be increased by the increment of the administered drug dosage and duration. On the other hand, the regeneration and healing in Dorsal Spinal Ganglion will be improved by increase of administration time and vitamin B12 dose, indicating that such vitamin was able to progress recovery process of peripheral nerves damage in experimental rats. Finally, our results have important implications for elucidating the mechanisms of nerve regeneration. Moreover, the results showed that vitaminB12 had a proliferative effect on the dorsal root ganglion sensory neuron. Virtual slides The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/7395141841009256 PMID:23902646

2013-01-01

240

Urinary Methylmalonic Acid as an Indicator of Early Vitamin B12 Deficiency and Its Role in Polyneuropathy in Type 2 Diabetes  

PubMed Central

The rising incidence of diabetes and its negative impact on quality of life highlights the urgent need to develop biomarkers of early nerve damage. Measurement of total vitamin B12 has some limitations. We want to determine the levels of urinary methylmalonic acid and its relationships with serum vitamin B12 and polyneuropathy. The 176 Chinese patients with Type 2 diabetes mellitus were divided into 3 groups according to the levels of vitamin B12. A gas chromatography mass spectrometric technique was used to determine blood methylmalonic acid and urinary methylmalonic acid. The diagnosis of distal diabetic polyneuropathy was based on the determination of bilateral limb sensory and motor nerve conduction velocity and amplitude with electromyogram. Multiple regression analysis revealed that urinary methylmalonic acid/creatinine, blood methylmalonic acid, and so forth were variables that influenced diabetic polyneuropathy significantly. Nerve sensory conduction velocity and nerve amplitude in the group of urinary methylmalonic acid/creatinine >3.5?mmol/mol decreased significantly. Superficial peroneal nerve sensory and motor conduction velocity and ulnar nerve compound motor active potential amplitude were inversely correlated with urinary methylmalonic acid/creatinine. Urinary methylmalonic acid correlates with serum vitamin B12 levels in person with diabetes and is a sensitive marker of early polyneuropathy. PMID:24719898

Sun, Ai-li; Ni, Yi-hong; Li, Xiao-bo; Zhuang, Xiang-hua; Liu, Yuan-tao; Liu, Xin-hua; Chen, Shi-hong

2014-01-01

241

Urinary methylmalonic acid as an indicator of early vitamin B12 deficiency and its role in polyneuropathy in type 2 diabetes.  

PubMed

The rising incidence of diabetes and its negative impact on quality of life highlights the urgent need to develop biomarkers of early nerve damage. Measurement of total vitamin B12 has some limitations. We want to determine the levels of urinary methylmalonic acid and its relationships with serum vitamin B12 and polyneuropathy. The 176 Chinese patients with Type 2 diabetes mellitus were divided into 3 groups according to the levels of vitamin B12. A gas chromatography mass spectrometric technique was used to determine blood methylmalonic acid and urinary methylmalonic acid. The diagnosis of distal diabetic polyneuropathy was based on the determination of bilateral limb sensory and motor nerve conduction velocity and amplitude with electromyogram. Multiple regression analysis revealed that urinary methylmalonic acid/creatinine, blood methylmalonic acid, and so forth were variables that influenced diabetic polyneuropathy significantly. Nerve sensory conduction velocity and nerve amplitude in the group of urinary methylmalonic acid/creatinine >3.5 mmol/mol decreased significantly. Superficial peroneal nerve sensory and motor conduction velocity and ulnar nerve compound motor active potential amplitude were inversely correlated with urinary methylmalonic acid/creatinine. Urinary methylmalonic acid correlates with serum vitamin B12 levels in person with diabetes and is a sensitive marker of early polyneuropathy. PMID:24719898

Sun, Ai-li; Ni, Yi-hong; Li, Xiao-bo; Zhuang, Xiang-hua; Liu, Yuan-tao; Liu, Xin-hua; Chen, Shi-hong

2014-01-01

242

Effects of Altered Maternal Folic Acid, Vitamin B12 and Docosahexaenoic Acid on Placental Global DNA Methylation Patterns in Wistar Rats  

PubMed Central

Potential adverse effects of excess maternal folic acid supplementation on a vegetarian population deficient in vitamin B12 are poorly understood. We have previously shown in a rat model that maternal folic acid supplementation at marginal protein levels reduces brain omega-3 fatty acid levels in the adult offspring. We have also reported that reduced docosahexaenoic acid (DHA) levels may result in diversion of methyl groups towards DNA in the one carbon metabolic pathway ultimately resulting in DNA methylation. This study was designed to examine the effect of normal and excess folic acid in the absence and presence of vitamin B12 deficiency on global methylation patterns in the placenta. Further, the effect of maternal omega 3 fatty acid supplementation on the above vitamin B12 deficient diets was also examined. Our results suggest maternal folic acid supplementation in the absence of vitamin B12 lowers plasma and placental DHA levels (p<0.05) and reduces global DNA methylation levels (p<0.05). When this group was supplemented with omega 3 fatty acids there was an increase in placental DHA levels and subsequently DNA methylation levels revert back to the levels of the control group. Our results suggest for the first time that DHA plays an important role in one carbon metabolism thereby influencing global DNA methylation in the placenta. PMID:21423696

Kulkarni, Asmita; Dangat, Kamini; Kale, Anvita; Sable, Pratiksha; Chavan-Gautam, Preeti; Joshi, Sadhana

2011-01-01

243

A Combined Supplementation of Omega-3 Fatty Acids and Micronutrients (Folic Acid, Vitamin B12) Reduces Oxidative Stress Markers in a Rat Model of Pregnancy Induced Hypertension  

PubMed Central

Objectives Our earlier studies have highlighted that an altered one carbon metabolism (vitamin B12, folic acid, and docosahexaenoic acid) is associated with preeclampsia. Preeclampsia is also known to be associated with oxidative stress and inflammation. The current study examines whether maternal folic acid, vitamin B12 and omega-3 fatty acid supplementation given either individually or in combination can ameliorate the oxidative stress markers in a rat model of pregnancy induced hypertension (PIH). Materials and Methods Pregnant Wistar rats were assigned to control and five treatment groups: PIH; PIH + vitamin B12; PIH + folic acid; PIH + Omega-3 fatty acids and PIH + combined micronutrient supplementation (vitamin B12 + folic acid + omega-3 fatty acids). L-Nitroarginine methylester (L-NAME; 50 mg/kg body weight/day) was used to induce hypertension during pregnancy. Blood Pressure (BP) was recorded during pregnancy and dams were dissected at d20 of gestation. Results Animals from the PIH group demonstrated higher (p<0.01 for both) systolic and diastolic BP; lower (p<0.01) pup weight; higher dam plasma homocysteine (p<0.05) and dam and offspring malondialdehyde (MDA) (p<0.01), lower (p<0.05) placental and offspring liver DHA and higher (p<0.01) tumor necrosis factor–alpha (TNF–?) levels as compared to control. Individual micronutrient supplementation did not offer much benefit. In contrast, combined supplementation lowered systolic BP, homocysteine, MDA and placental TNF-? levels in dams and liver MDA and protein carbonyl in the offspring as compared to PIH group. Conclusion Key constituents of one carbon cycle (folic acid, vitamin B12 and DHA) may play a role in reducing oxidative stress and inflammation in preeclampsia. PMID:25405347

Kemse, Nisha G.; Kale, Anvita A.; Joshi, Sadhana R.

2014-01-01

244

Anemia - B12 deficiency  

MedlinePLUS

... vitamin B12. They include: Chronic alcoholism Crohn disease, celiac disease, infection with the fish tapeworm, or other problems ... may no longer be needed after Crohn disease, celiac disease, or alcoholism is properly treated. Your doctor or ...

245

Selective intestinal malabsorption of vitamin B12 displays recessive Mendelian inheritance: Assignment of a locus to chromosome 10 by linkage  

SciTech Connect

Juvenile megaloblastic anemia caused by selective intestinal malabsorption of vitamin B12 has been considered a distinct condition displaying autosomal recessive inheritance. It appears to have a worldwide distribution, and comparatively high incidences were reported 30 years ago in Finland and Norway. More recently, the Mendelian inheritance of the condition has been questioned because almost no new cases have occurred in these populations. Here we report linkage studies assigning a recessive-gene locus for the disease to chromosome 10 in previously diagnosed multiplex families from Finland and Norway, proving the Mendelian mode of inheritance. The locus is tentatively assigned to the 6-cM interval between markers D10S548 and D10S466, with a multipoint maximum lod score (Z{sub max}) of 5.36 near marker D10S1477. By haplotype analysis, the healthy sibs in these families did not appear to constitute any examples of nonpenetrance. We hypothesize that the paucity of new cases in these populations is due either to a dietary effect on the gene penetrance that has changed with time, or to a drop in the birth rate in subpopulations showing enrichment of the mutation, or to both of these causes. 38 refs., 4 figs., 2 tabs.

Aminoff, M.; Tahvanainen, E.; Chapelle, A. de la [Univ. of Helsinki (Finland)] [and others

1995-10-01

246

A patient with an inborn error of vitamin B12 metabolism (cblF) detected by newborn screening.  

PubMed

A neonate, who was found to have an elevated C3/C2 ratio and minimally elevated propionylcarnitine on newborn screening, was subsequently identified as having the rare cblF inborn error of vitamin B12 (cobalamin) metabolism. This disorder is characterized by the retention of unmetabolized cobalamin in lysosomes such that it is not readily available for cellular metabolism. Although cultured fibroblasts from the patient did not show the expected functional abnormalities of the cobalamin-dependent enzymes, methylmalonyl-CoA mutase and methionine synthase, they did show reduced synthesis of the active cobalamin cofactors adenosylcobalamin and methylcobalamin. Mutation analysis of LMBRD1 established that the patient had the cblF disorder. Treatment was initiated promptly, and the patient showed a robust response to regular injections of cyanocobalamin, and she was later switched to hydroxocobalamin. Currently, at 3 years of age, the child is clinically well, with appropriate development. Adjusted newborn screening cutoffs in Ontario allowed detection of a deficiency that might not have otherwise been identified, allowing early treatment and perhaps preventing the adverse sequelae seen in some untreated patients. PMID:23776111

Armour, Christine M; Brebner, Alison; Watkins, David; Geraghty, Michael T; Chan, Alicia; Rosenblatt, David S

2013-07-01

247

In-situ biochemical remediation of chlorinated organic compounds present as DNAPL using vitamin B12 and reduced titanium  

SciTech Connect

The feasibility of using a biochemical treatment for the cleanup of DNAPL solvents in the saturated zone was tested using an in-situ large vertical column. Laboratory column studies have shown that a mixture of vitamin B12 and titanium citrate pumped through a column containing 100 {mu}L of tetrachloroethene can completely dissolve and degrade the residual to ethene in a few days. A vertical test column, 80 cm in diameter was installed within a sheet-pile cell isolating a portion of aquifer at CFB Borden. An equimolar mixture of tetrachloroethene and 1,1,1-trichloroethane was injected below the water table to form a residual DNAPL. The injection withdrawal system was operated in an upward flow mode over a 2 m height. In order for the reaction to be proceed, the in-situ pH must be greater than 7 and the Eh lower than -480 mV. The redox of the aquifer and the formation of reaction products was monitored on site, through 8 side pods equipped with stainless steel tubing terminated with 40 {mu}m porous cups, installed at different heights in the test column. The volatile products at the withdrawal well were monitored on-line by dynamic headspace analysis/gas chromatography.

Lesage, S. [National Water Research Institute, Burlington, Ontario (Canada); Sorel, D.; Cherry, J.A. [Univ. of Waterloo, Ontario (Canada)

1995-12-31

248

Crystal structure of putative CbiT from Methanocaldococcus jannaschii: an intermediate enzyme activity in cobalamin (vitamin B12) biosynthesis  

PubMed Central

Background In the anaerobic pathway of cobalamin (vitamin B12) synthesis, the CbiT enzyme plays two roles, as a cobalt-precorrin-7 C15-methyltransferase and a C12-decarboxylase, to produce the intermediate, cobalt-precorrin 8. Results The primary structure of the hypothetical protein MJ0391, from Methanocaldococcus jannaschii, suggested that MJ0391 is a putative CbiT. Here, we report the crystal structure of MJ0391, solved by the MAD procedure and refined to final R-factor and R-free values of 19.8 & 27.3%, respectively, at 2.3 Å resolution. The asymmetric unit contains two NCS molecules, and the intact tetramer generated by crystallographic symmetry may be functionally important. The overall tertiary structure and the tetrameric arrangements are highly homologous to those found in MT0146/CbiT from Methanobacterium thermoautotrophicum. Conclusions The conservation of functional residues in the binding site for the co-factor, AdoMet, and in the putative precorrin-7 binding pocket suggested that MJ0391 may also possess CbiT activity. The putative function of MJ0391 is discussed, based on structural homology. PMID:23688113

2013-01-01

249

Rationale and design of the B-PROOF study, a randomized controlled trial on the effect of supplemental intake of vitamin B12 and folic acid on fracture incidence  

Microsoft Academic Search

Background Osteoporosis is a major health problem, and the economic burden is expected to rise due to an increase in life expectancy throughout the world. Current observational evidence suggests that an elevated homocysteine concentration and poor vitamin B12 and folate status are associated with an increased fracture risk. As vitamin B12 and folate intake and status play a large role

Wijngaarden van J. P; R. A. M. Dhonukshe-Rutten; Schoor van N. M; Velde van der N; K. M. A. Swart; A. W. Enneman; Dijk van S. C; E. M. Brouwer; M. C. Zillikens; Meurs van J. B. J; J. Brug; A. G. Uitterlinden; P. Lips; Groot de C. P. G. M

2011-01-01

250

Trifluoracetic acid-assisted crystallization of vitamin B12 results in protonation of the phosphate group of the nucleotide loop: insight into the influence of crystal packing forces on vitamin B12 structures.  

PubMed

In the course of experiments concerning our ongoing project on the synthesis of vitamin B(12) (cyanocobalamin, CNCbl) bioconjugates for drug-delivery purposes, we observed the formation of well-shaped red parallelepipeds from a concentrated aqueous solution of the HPLC-purified vitamin. The X-ray structural investigation (MoK(?)) at 98 K on these crystals revealed a CNCbl-TFA salt of formula [CNCbl(H)](TFAc)·14H(2)O (1, where TFA = trifluoracetic acid; TFAc(-) = trifluoracetate anion), in which a proton transfer from the trifluoracetic acid to the phosphate-O4P oxygen atoms is observed. 1 crystallizes in the standard orthorhombic P2(1)2(1)2(1) space group, a = 16.069(2) Å, b = 20.818(2) Å, c = 24.081(2) Å, Z = 4. The final full-matrix least-squares refinements on F(2) converged with R(1) = 4.1% for the 18957 significant reflections, a very low crystallographic residual for cobalamins, which facilitated the analysis of the extensive network of hydrogen bonds within the lattice. To the best of our knowledge, this is the first cobalamin structure to show protonation of the phosphate group of the cobalamin nucleotide loop. In this work, the crystal structure of 1 is analyzed and compared to other CNCbls reported in the literature, namely, CNCbl·3PrOH·12H(2)O (2, PrOH = propyl alcohol), CNCbl·acetone·20H(2)O (3), CNCbl·2LiCl·10.2H(2)O (4), and CNCbl·2KCl·10.6H(2)O (5). The analysis confirmed that protonation of the phosphate leaves the major CNCbl structural parameters unaffected, so that 1 can be considered an "unmodified" Cbl solvate. However, comparison between 1-5 led to interesting findings. In fact, although the cobalt(III) coordination sphere in 1-5 is similar, significant differences could be noted in the upward fold angle of the corrin macrocycle, a parameter commonly related to the steric hindrance of the axial lower "?" nucleotide-base and the electronic trans influence of the upper "?" substituent. This suggests that crystal-packing forces may influence the corrin deformation as well. Herein we explore, on the basis of the newly acquired structure and reported crystallographic data, whether the incongruities among 1-5 have to be attributed to random crystal packing effects or if it is possible to associate them with specific crystal packing (clusters). PMID:21128680

Marino, Nadia; Rabideau, Amy E; Doyle, Robert P

2011-01-01

251

Severe vitamin B12 deficiency in an exclusively breastfed 5-month-old Italian infant born to a mother receiving multivitamin supplementation during pregnancy  

PubMed Central

Background In infants, vitamin B12 deficiency may be due to an inborn error of absorption and metabolism, or nutritional problems. Case presentation An exclusively breastfed 5-month-old Italian male infant, who was born after a normal full-term pregnancy to a vegan mother who was apparently daily treated with a multivitamin oral preparation during the second and third trimester, was hospitalised because of poor weight gain, feeding difficulties, severe pallor, muscle hypotonia and somnolence. Upon admission, his weight, length and head circumference were below the third percentile, he had an enlarged liver and spleen, and showed a significant delay in developmental milestones and communicative reactions. He had a hemoglobin level of 4.7?g/dL with an MCV of 84.2?fL, a white blood cell count of 4,680/mm3, and a platelet count of 45,000/mm3. His serum vitamin B12 level was 57?pg/mL (normal value 180–500?pg/mL) and serum folate level 12.8?ng/mL (normal value >3?ng/mL). The results of metabolic examinations excluded a cobalamin C disorder, whereas nutritional screening showed a serum iron concentration of 9??g/dL and serum ferritin of 4?ng/mL. Magnetic resonance imaging of the brain showed mild dilatation of the lateral ventricles with diffuse delayed myelination. The child was diagnosed as having vitamin B12 and iron deficiency due to nutritional inadequacy and was immediately treated with packed red blood cells, intramuscular vitamin B12 injections, and iron supplementation. A few days after the start of therapy, his hemoglobin levels and other hematological parameters rapidly improved, and a clinical improvement was observed within few weeks. There was an increase in his achievement of developmental milestones, but his development was still retarded seven months after the start of therapy. Conclusion This case underlines the importance of adequately controlling maternal vitamin B12 intake during pregnancy by means of supplementation which, in the case of vegan mothers, should be significantly greater than that usually given. Moreover, the supplementation should be continued during lactation in order to avoid the development of signs of deficiency that may be associated with persistent neurological problems in infants. The case also highlights the need to consider vitamin B12 deficiency in infants with severe anemia even if their hematological parameters do not indicate megaloblastic anemia because the concomitant presence of substantial iron deficiency may modify the characteristics of the anemia. PMID:22726312

2012-01-01

252

Measured Electron Spin Relaxation Rates in Frozen Solutions of Azurin, VITAMIN-B12R, and Nitrosyl Ferrous Myoglobin.  

NASA Astrophysics Data System (ADS)

Rates in frozen glycerin/water solutions at temperatures between 1.4 K and 20 K are reported for a copper-containing protein, azurin, and a cobalt-containing biomolecular complex, vitamin B_{rm 12r}, the paramagnetic product of the photolysis of coenzyme B_{12}. Results are interpreted in terms of a spectral dimensionality. Rates are also reported for nitrosyl ferrous myoglobin in frozen water solution, which exhibits a dominant one-phonon relaxation process up to 20 K and thus does not reveal spectral dimensionality. The anomalous variation of rate with temperature observed in several iron-containing proteins is not conspicuous here. In a model two-phonon mechanism of relaxation, temperature dependence is fixed by a spectral dimensionality, m, which specifies the variation of vibrational density of states with frequency rho(nu ) ~ nu ^{rm m-1} and is named in analogy with the Debye density of states in 1-, 2-, and 3-dimensional crystals. At sufficiently high temperatures, a non-resonant two-phonon process (Raman) should dominate the relaxation of a paramagnetic ion unless low-lying (under ^{~}70 cm^ {-1}) electronic states are present, as in many rare earths and in high spin ferric complexes, including many ferric proteins. The temperature dependence of the Raman rate for a Kramers ion (odd number of electrons) is T^{rm 3+2m} if temperature is sufficiently lower than Theta = hnu_{rm max} /k, the Debye temperature. The values of m from relaxation data on frozen solutions of a protein have sometimes been dependent upon solvent conditions. The maximum values of m for heme proteins, iron-sulfur proteins, and one copper -and-iron-containing protein, have ranged from about 1.3 to 1.8. Pulse saturation/recovery was used. The recoveries were not exponential, but rates were estimated from semilogarithmic displays of signals or from numerical fitting. The temperature dependence of the rates for azurin between 1.5 K and 22 K can be fit with a spectral dimensionality of 3 and a rather low Debye temperature near 69 K, in contrast to iron proteins. Relaxation of vitamin B_{ rm 12r} differed between samples, indicating varied photolysis or freezing. The Raman relaxation was well fit by a simple power law in temperature, but the values of m varied from 1.14 to 1.48 between samples.

Muench, Philip James

253

Elevated Plasma Vitamin B12 Levels as a Marker for Cancer: A Population-Based Cohort Study  

PubMed Central

Background A substantial proportion of patients referred for plasma vitamin B12 (cobalamin [Cbl]) measurement present with high Cbl levels, which have been reported in patients with different cancer types. However, the cancer risk among patients with newly diagnosed high Cbl levels has not been adequately examined. Methods We conducted this cohort study using population-based Danish medical registries. Patients referred for Cbl measurement with levels greater than the lower reference limit (?200 pmol/L) were identified from the population of Northern Denmark during the period of 1998 to 2009 using a database of laboratory test results covering the entire population. Data on cancer incidence (follow-up 1998–2010), Cbl treatment, and prior diagnoses were obtained from medical registries. Patients receiving Cbl treatment were excluded. Cancer risks were calculated as standardized incidence ratios (SIRs) with 95% confidence intervals (CIs), stratified by plasma Cbl levels. All statistical tests were two-sided. Results We identified 333 667 persons without prevalent cancer and not receiving Cbl treatment. Six percent had Cbl levels greater than the upper reference limit (?601 pmol/L). Cancer risk increased with higher Cbl levels and was highest during the first year of follow-up (Cbl 601–800 pmol/L: SIR = 3.44, 95% CI = 3.14 to 3.76; Cbl >800 pmol/L: SIR = 6.27, 95% CI = 5.70 to 6.88; both P < .001). The risks were particularly elevated for hematological and smoking- and alcohol-related cancers for persons with high Cbl levels. Conclusions High Cbl levels were associated with the risk of subsequently diagnosed cancer, mostly within the first year of follow-up. This may have clinical implications for the interpretation of high Cbl levels. PMID:24249744

2013-01-01

254

The vitamin B12 analog cobinamide is an effective hydrogen sulfide antidote in a lethal rabbit model  

PubMed Central

Background and purpose Hydrogen sulfide (H2S) is a highly toxic gas for which no effective antidotes exist. It acts, at least in part, by binding to cytochrome c oxidase, causing cellular asphyxiation and anoxia. We investigated the effects of three different ligand forms of cobinamide, a vitamin B12 analog, to reverse sulfide (NaHS) toxicity. Methods New Zealand white rabbits received a continuous intravenous (IV) infusion of NaHS (3 mg/min) until expiration or a maximum 270 mg dose. Animals received six different treatments, administered at the time when they developed signs of severe toxicity: Group 1—saline (placebo group, N = 9); Group 2—IV hydroxocobalamin (N = 7); Group 3—IV aquohydroxocobinamide (N = 6); Group 4—IV sulfitocobinamide (N = 6); Group 5—intramuscular (IM) sulfitocobinamide (N = 6); and Group 6—IM dinitrocobinamide (N = 8). Blood was sampled intermittently, and systemic blood pressure and deoxygenated and oxygenated hemoglobin were measured continuously in peripheral muscle and over the brain region; the latter were measured by diffuse optical spectroscopy (DOS) and continuous wave near infrared spectroscopy (CWNIRS). Results Compared with the saline controls, all cobinamide derivatives significantly increased survival time and the amount of NaHS that was tolerated. Aquohydroxocobinamide was most effective (261.5 ± 2.4 mg NaHS tolerated vs. 93.8 ± 6.2 mg in controls, p < 0.0001). Dinitrocobinamide was more effective than sulfitocobinamide. Hydroxocobalamin was not significantly more effective than the saline control. Conclusions Cobinamide is an effective agent for inhibiting lethal sulfide exposure in this rabbit model. Further studies are needed to determine the optimal dose and form of cobinamide and route of administration. PMID:24716792

BRENNER, M.; BENAVIDES, S.; MAHON, S. B.; LEE, J.; YOON, D.; MUKAI, D.; VISEROI, M.; CHAN, A.; JIANG, J.; NARULA, N.; AZER, S. M.; ALEXANDER, C.; BOSS, G. R.

2014-01-01

255

Human Vitamin B12 Absorption and Metabolism are Measured by Accelerator Mass Spectrometry Using Specifically Labeled 14C-Cobalamin  

SciTech Connect

There is need for an improved test of human ability to assimilate dietary vitamin B{sub 12}. Assaying and understanding absorption and uptake of B{sub 12} is important because defects can lead to hematological and neurological complications. Accelerator mass spectrometry (AMS) is uniquely suited for assessing absorption and kinetics of {sup 14}C-labeled substances after oral ingestion because it is more sensitive than decay counting and can measure levels of carbon-14 ({sup 14}C) in microliter volumes of biological samples, with negligible exposure of subjects to radioactivity. The test we describe employs amounts of B{sub 12} in the range of normal dietary intake. The B{sub 12} used was quantitatively labeled with {sup 14}C at one particular atom of the DMB moiety by exploiting idiosyncrasies of Salmonellametabolism. In order to grow aerobically on ethanolamine, S. entericamust be provided with either pre-formed B{sub 12} or two of its precursors: cobinamide and dimethylbenzimidazole (DMB). When provided with {sup 14}C-DMB specifically labeled in the C2 position, cells produced {sup 14}C-B{sub 12} of high specific activity (2.1 GBq/mmol, 58 mCi/mmol) and no detectable dilution of label from endogenous DMB synthesis. In a human kinetic study, a physiological dose (1.5 mg, 2.2 KBq/59 nCi) of purified {sup 14}C-B{sub 12} was administered and showed plasma appearance and clearance curves consistent with the predicted behavior of the pure vitamin. This method opens new avenues for study of B{sub 12} assimilation.

Carkeet, C; Dueker, S R; Lango, J; Buchholz, B A; Miller, J W; Green, R; Hammock, B D; Roth, J R; Anderson, P J

2006-01-26

256

Advances in standardization of laboratory measurement procedures: implications for measuring biomarkers of folate and vitamin B-12 status in NHANES1234  

PubMed Central

Population studies such as NHANES analyze large numbers of laboratory measurements and are often performed in different laboratories using different measurement procedures and over an extended period of time. Correct clinical and epidemiologic interpretations of the results depend on the accuracy of those measurements. Unfortunately, considerable variability has been observed among assays for folate, vitamin B-12, and related biomarkers. In the past few decades, the science of metrology has advanced considerably, with the development of improved primary reference measurement procedures and high-level reference materials, which can serve as the basis for accurate measurement. A rigorous approach has been established for making field methods traceable to the highest-level reference measurement procedures and reference materials. This article reviews some basic principles of metrology and describes their recent application to measurements of folate and vitamin B-12. PMID:21562088

Eckfeldt, John H

2011-01-01

257

Treatment of multiple sclerosis with lofepramine, l-phenylalanine and vitamin B 12: mechanism of action and clinical importance: roles of the locus coeruleus and central noradrenergic systems  

Microsoft Academic Search

In a randomized, placebo-controlled double-blind trial a combination of lofepramine, phenylalanine and vitamin B12 was found to be effective in relieving the symptoms of multiple sclerosis (MS). The effect occurred within 2–4 weeks, and improved all types of symptoms in all types of MS. The combination was also effective in relieving symptoms in patients with chronic pain and chronic fatigue.

C Loder; J Allawi; D. F Horrobin

2002-01-01

258

Relationship of folate, vitamin B12 and methylation of insulin-like growth factor-II in maternal and cord blood  

PubMed Central

Background/Objective One of the speculated mechanisms underlying fetal origin hypothesis of breast cancer is the possible influence of maternal environment on epigenetic regulation, such as changes in DNA methylation of the insulin-like growth factor-2 (IGF2) gene. The aim of the study is to investigate the relationship between folate, vitamin B12 and methylation of the IGF2 gene in maternal and cord blood. Subjects/Methods We conducted a cross-sectional study to measure methylation patterns of IGF2 in promoters 2 (P2) and 3 (P3). Results The percentage of methylation in IGF2 P3 was higher in maternal blood than in cord blood (p<0.0001), while the methylation in P2 was higher in cord blood than in maternal blood (p=0.016). P3 methylation was correlated between maternal and cord blood (p<0.0001) but not P2 (p=0.06). The multivariate linear regression model showed that methylation patterns of both promoters in cord blood were not associated with serum folate levels in either cord or maternal blood, while the P3 methylation patterns were associated with serum levels of vitamin B12 in mother’s blood (MC=?0.22, p=0.0014). Methylation patterns in P2 of maternal blood were associated with serum levels of vitamin B12 in mother’s blood (MC=?0.23, p=0.012), exposure to passive smoking (MC=0.46, p=0.034) and mother’s weight gain during pregnancy (MC=0.23, p=0.019). Conclusions The study suggests that environment influences methylation patterns in maternal blood, and then the maternal patterns influence the methylation status and levels of folate and vitamin B12 in cord blood. PMID:21245875

Ba, Yue; Yu, Hebert; Liu, Fudong; Geng, Xue; Zhu, Cairong; Zhu, Quan; Zheng, Tongzhang; Ma, Shuangge; Wang, Gang; Li, Zhiyuan; Zhang, Yawei

2010-01-01

259

Methylenetetrahydrofolate reductase C677T genotype affects promoter methylation of tumor-specific genes in sporadic colorectal cancer through an interaction with folate\\/vitamin B12 status  

Microsoft Academic Search

AIM: To evaluate joint effects of Methylentetra- hydrofolate reductase (MTHFR ) C677T genotypes, and serum folate\\/vitamin B12 concentrations on promoter methylation of tumor-associated genes among Iranian colorectal cancer patients. METHODS: We examined the associations between MTHFR C677T genotype, and promoter methylation of P16 , hMLH1 , and hMSH2 tumor-related genes among 151 sporadic colorectal cancer patients. The promoter methylation of

Pooneh Mokarram; Fakhraddin Naghibalhossaini

2008-01-01

260

Vitamin B12 Status Is Inversely Associated with Plasma Homocysteine in Young Women with C677T and\\/or A1298C Methylenetetrahydrofolate Reductase Polymorphisms1  

Microsoft Academic Search

Methylenetetrahydrofolate reductase (MTHFR) polymorphisms may negatively influence one-carbon metabolism and increase health risks in women of reproductive age. The effect of MTHFR single nucleotide polymorphisms at bp 677 and\\/or 1298 and differences in folate and vitamin B-12 status on plasma homocysteine concentration in women of reproductive age (20 -30 y; n 186) were investigated. From the multivariate regression model, homozygotes

Lynn B. Bailey; Robert L. Duhaney; David R. Maneval; Gail P. A. Kauwell; Eoin P. Quinlivan; Steven R. Davis; Aisha Cuadras; Alan D. Hutson; Jesse F. Gregory

261

Iron, folate and vitamin B12 status of apparently healthy Irish adult women attending general practitioners in inner-city Dublin  

Microsoft Academic Search

There is substantial related morbidity and mortality among men and women in developed countries. Certain events during the course of a woman’s life such as menstruation, pregnancy, lactation and the menopause may compromise haematinic nutrient status. The purpose of this study was to investigate iron, folate and vitamin B12 status among a sample of apparently healthy, non-pregnant Irish adult women

Helen R. Casey

2002-01-01

262

Folate and Vitamin B12 May Play a Critical Role in Lowering the HPV 16 Methylation-Associated Risk of Developing Higher Grades of CIN.  

PubMed

We previously reported that a higher degree of methylation of CpG sites in the promoter (positions 31, 37, 43, 52, and 58) and enhancer site 7862 of human papillomavirus (HPV) 16 was associated with a lower likelihood of being diagnosed with HPV 16-associated CIN 2+. The purpose of this study was to replicate our previous findings and, in addition, to evaluate the influence of plasma concentrations of folate and vitamin B12 on the degree of HPV 16 methylation (HPV 16m). The study included 315 HPV 16-positive women diagnosed with either CIN 2+ or ?CIN 1. Pyrosequencing technology was used to quantify the degree of HPV 16m. We reproduced the previously reported inverse association between HPV 16m and risk of being diagnosed with CIN 2+. In addition, we observed that women with higher plasma folate and HPV 16m or those with higher plasma vitamin B12 and HPV 16m were 75% (P < 0.01) and 60% (P = 0.02) less likely to be diagnosed with CIN 2+, respectively. With a tertile increase in the plasma folate or vitamin B12, there was a 50% (P = 0.03) and 40% (P = 0.07) increase in the odds of having a higher degree of HPV 16m, respectively. This study provides initial evidence that methyl donor micronutrients, folate and vitamin B12, may play an important role in maintaining a desirably high degree of methylation at specific CpG sites in the HPV E6 promoter and enhancer that are associated with the likelihood of being diagnosed with CIN 2+. Cancer Prev Res; 7(11); 1128-37. ©2014 AACR. PMID:25145486

Piyathilake, Chandrika J; Macaluso, Maurizio; Chambers, Michelle M; Badiga, Suguna; Siddiqui, Nuzhat R; Bell, Walter C; Edberg, Jeffrey C; Partridge, Edward E; Alvarez, Ronald D; Johanning, Gary L

2014-11-01

263

Relationship of folate, vitamin B12 and methylation of insulin-like growth factor-II in maternal and cord blood  

Microsoft Academic Search

Background\\/Objective:One of the speculated mechanisms underlying fetal origin hypothesis of breast cancer is the possible influence of maternal environment on epigenetic regulation, such as changes in DNA methylation of the insulin-like growth factor-2 (IGF2) gene. The aim of the study is to investigate the relationship between folate, vitamin B12 and methylation of the IGF2 gene in maternal and cord blood.Subjects\\/Methods:We

Y Ba; H Yu; F Liu; X Geng; C Zhu; Q Zhu; T Zheng; S Ma; G Wang; Z Li; Y Zhang

2011-01-01

264

Effect of the vitamin B12-binding protein haptocorrin present in human milk on a panel of commensal and pathogenic bacteria  

Microsoft Academic Search

Background  Haptocorrin is a vitamin B12-binding protein present in high amounts in different body fluids including human milk. Haptocorrin\\u000a has previously been shown to inhibit the growth of specific E. coli strains, and the aim of the present study was to elucidate whether the antibacterial properties of this protein may exert\\u000a a general defense against pathogens and\\/or affect the composition of

Henrik R Jensen; Martin F Laursen; Dorte L Lildballe; Jens B Andersen; Ebba Nexø; Tine R Licht

2011-01-01

265

Genetic and Non-Genetic Influences during Pregnancy on Infant Global and Site Specific DNA Methylation: Role for Folate Gene Variants and Vitamin B12  

PubMed Central

Inter-individual variation in patterns of DNA methylation at birth can be explained by the influence of environmental, genetic and stochastic factors. This study investigates the genetic and non-genetic determinants of variation in DNA methylation in human infants. Given its central role in provision of methyl groups for DNA methylation, this study focuses on aspects of folate metabolism. Global (LUMA) and gene specific (IGF2, ZNT5, IGFBP3) DNA methylation were quantified in 430 infants by Pyrosequencing®. Seven polymorphisms in 6 genes (MTHFR, MTRR, FOLH1, C?S, RFC1, SHMT) involved in folate absorption and metabolism were analysed in DNA from both infants and mothers. Red blood cell folate and serum vitamin B12 concentrations were measured as indices of vitamin status. Relationships between DNA methylation patterns and several covariates viz. sex, gestation length, maternal and infant red cell folate, maternal and infant serum vitamin B12, maternal age, smoking and genotype were tested. Length of gestation correlated positively with IGF2 methylation (rho?=?0.11, p?=?0.032) and inversely with ZNT5 methylation (rho?=??0.13, p?=?0.017). Methylation of the IGFBP3 locus correlated inversely with infant vitamin B12 concentration (rho?=??0.16, p?=?0.007), whilst global DNA methylation correlated inversely with maternal vitamin B12 concentrations (rho?=?0.18, p?=?0.044). Analysis of common genetic variants in folate pathway genes highlighted several associations including infant MTRR 66G>A genotype with DNA methylation (?2?=?8.82, p?=?0.003) and maternal MTHFR 677C>T genotype with IGF2 methylation (?2?=?2.77, p?=?0.006). These data support the hypothesis that both environmental and genetic factors involved in one-carbon metabolism influence DNA methylation in infants. Specifically, the findings highlight the importance of vitamin B12 status, infant MTRR genotype and maternal MTHFR genotype, all of which may influence the supply of methyl groups for DNA methylation. In addition, gestational length appears to be an important determinant of infant DNA methylation patterns. PMID:22479380

McKay, Jill A.; Groom, Alexandra; Potter, Catherine; Coneyworth, Lisa J.; Ford, Dianne; Mathers, John C.; Relton, Caroline L.

2012-01-01

266

Effect of hormonal contraceptives on vitamin B12 level and the association of the latter with bone mineral density  

PubMed Central

Background The study was conducted to estimate the effect of depot medroxyprogesterone acetate (DMPA) and oral contraceptives (OC) containing 20 mcg ethinyl estradiol on serum B12 and whether observed changes impact bone mineral density (BMD). Study Design Serum B12 and BMD at the lumbar spine and femoral neck were measured on 703 women using OC, DMPA, or nonhormonal (NH) birth control at baseline and every 6 months thereafter for 3 years. Results OC and DMPA users experienced greater decreases in B12 than NH users (p<.001). A sharp decrease in B12 was observed during the first 6 months of hormonal contraceptive use (OC: 97 pg/mL and DMPA: 64 pg/mL) in contrast to 14 pg/mL among NH users (20%, 13% and 3% of their baseline values, respectively). Over the following 30 months, B12 levels of OC users remained almost flat while DMPA users had a further 22 units decrease. Very few women demonstrated B12 deficiency. Moreover, B12 levels were not associated with BMD. Conclusion Hormonal contraception causes B12 levels to decrease, but this does not appear to be clinically significant or affect BMD. PMID:22464408

Berenson, Abbey B.; Rahman, Mahbubur

2012-01-01

267

Fundamental shift in vitamin B12 eco-physiology of a model alga demonstrated by experimental evolution  

E-print Network

extensively in animals, plants and fungi, little is known about their 322 significance in algal evolution. Transposons have, however, been identified in the genomes of 323 several algal species (Armbrust et al, 2004; Bowler et al, 2008; Cock et al, 2010... in response to the absence of environmental B12 (Figure 3). This temporary 336 ‘get out of jail free card’ could thus facilitate evolutionary escape from a B12-dependent 337 lifestyle before METE further deteriorates (Helliwell et al, 2011). If similar...

Helliwell, Katherine E.; Collins, Sinéad; Kazamia, Elena; Purton, Saul; Wheeler, Glen L.; Smith, Alison G.

2014-01-01

268

Synthesis, characterization, Co-S bond reactivity of a vitamin B12 model complex having pentafluorophenylthiolate as an axial ligand.  

PubMed

Heptamethyl (aquo)(pentafluorophenylthiolate)cobyrinate perchlorate, [(H2O)(C6F5S)Cob(III)7C1ester]ClO4, was synthesized as a B12 model complex having a thiolate ligand in the axial position. The axial ligand change in heptamethyl (diaquo)cobyrinate diperchlorate, [(H2O)2Cob(III)7C1ester](ClO4)2, from H2O to C6F5S(-) afforded the B12-thiolate complex. The B12-thiolate model complex was characterized by UV-vis, NMR and ESI-mass spectroscopies. The coordination of C6F5S(-) to the cobalt center affected the spectroscopic properties of the corrin ring through the electronic interaction between the axial ligand (C6F5S(-)) and the equatorial ligand (corrin). The photolysis of the B12-thiolate model complex led to the homolytic cleavage of the Co(iii)-S bond to form the Co(II) complex and the phenyl thiyl radical. The thermolysis of the B12-thiolate model complex also led to the homolytic cleavage of the Co(III)-S bond. Furthermore, the reactivity of the Co(III)-S bond of the B12-thiolate model complex was applied to the catalytic oxidation of C6F5SH to C6F5S-SC6F5. PMID:23463441

Tahara, Keishiro; Matsuzaki, Ayaka; Masuko, Takahiro; Kikuchi, Jun-ichi; Hisaeda, Yoshio

2013-05-14

269

Methylmalonic Acid quantified in dried blood spots provides a precise, valid, and stable measure of functional vitamin B-12 status in healthy women.  

PubMed

Methylmalonic acid (MMA) is a sensitive and specific functional biomarker of vitamin B-12 status, commonly assessed in plasma or serum. Dried blood spots (DBSs) allow simpler and more cost-efficient blood sampling than plasma. To facilitate convenient testing for vitamin B-12 deficiency in large-scale surveys and in population groups from remote areas, we developed a method for MMA quantification in DBSs and tested its applicability as well as the long-term stability of MMA in DBSs at various temperatures. MMA was extracted from an 8-mm DBS punch with water:methanol (95:5, v:v) and methyl-d3-malonic acid as the internal standard. After sample cleanup by ultrafiltration and hexane extraction, MMA was quantified by using reversed-phase LC-tandem mass spectrometry. Extraction conditions were optimized to maximize the detection signal and achieve DBS extract concentrations above the lowest limit of quantification (signal-to-noise ratio ? 10) of 10 nmol/L. Recovery was between 93% and 96%. Intra- and interassay variation (CV%) for DBS MMA was 0.49% and 2.3%, respectively. Calibrators showed linearity (R(2) = 0.998) between 10 and 10,000 nmol/L. In 94 healthy women, MMA concentrations in DBS extract (min-max: 10.2-80.5 nmol/L) and plasma (min-max: 68-950 nmol/L) were correlated (? = 0.90) (P < 0.001). MMA concentrations in DBSs were stable at room temperature for 1 wk, in the refrigerator for 8 wk, and at -80°C for at least 1 y. This simple and robust method allows quantification of MMA in DBSs of healthy individuals. The linear relation between plasma and DBS MMA suggests that DBS MMA could predict plasma MMA, the current reference indicator for functional vitamin B-12 deficiency. With the advantages of minimally invasive specimen collection and no need for laborious blood processing steps, this method has the potential to be a reliable, convenient, and field-applicable alternative for assessment of vitamin B-12 status. PMID:25143369

Schroder, Theresa H; Quay, Teo A W; Lamers, Yvonne

2014-10-01

270

The status of vitamins B6, B12, folate, and of homocysteine in geriatric home residents receiving laxatives or dietary fiber  

Microsoft Academic Search

Background  Vitamin B12 deficiency as a digestive disorder and constipation as a gastro motility disorder are common in the elderly. Laxative\\u000a treatment is often chosen without regard for gut health.\\u000a \\u000a \\u000a \\u000a Objective  To investigate whether the addition of oat-bran to the common oral diet for 12 weeks is able to reduce constipation and laxative\\u000a use and improve gut health. It is assumed that

Baerbel Sturtzel; A. Dietrich; K.-H. Wagner; C. Gisinger; I. Elmadfa

271

The status of vitamins B6, B12, folate, and of homocysteine in geriatric home residents receiving laxatives or dietary fiber  

Microsoft Academic Search

Background  Vitamin B12 deficiency as a digestive disorder and constipation as a gastro motility disorder are common in the elderly. Laxative\\u000a treatment is often chosen without regard for gut health.\\u000a \\u000a \\u000a \\u000a \\u000a Objective  To investigate whether the addition of oat-bran to the common oral diet for 12 weeks is able to reduce constipation and laxative\\u000a use and improve gut health. It is assumed that

Baerbel Sturtzel; A. Dietrich; K.-H. Wagner; C. Gisinger; I. Elmadfa

2010-01-01

272

Effect of physiological doses of oral vitamin B12 on plasma homocysteine - A randomized, placebo-controlled, double-blind trial in India  

PubMed Central

Background: Vitamin B12 (B12) deficiency is common in Indians and a major contributor to hyperhomocysteinemia, which may influence fetal growth, risk of type 2 diabetes and cardiovascular disease. Objective: To study the effect of physiological doses of B12 and folic acid on plasma total homocysteine (tHcy). Design: A cluster randomized, placebo-controlled, double-blind, 2x3 factorial trial, using the family as the randomization unit. Vitamin B12 was given as 2 or 10 ?g capsules, with or without 200 ?g folic acid, forming six groups (B0F0, B2F0, B10F0, B0F200, B2F200, B10F200). Plasma tHcy was measured before and after 4 and 12 mo of supplementation. Results: Three hundred individuals from 119 families in the Pune Maternal Nutrition Study were randomised. There was no interaction between B12 and folic acid (P=0.14) in relation to tHcy change and their effects were analyzed separately: B0 vs. B2 vs. B10; and F0 vs. F200. At 12 mo, tHcy fell by a mean 5.9 (95% CI: ?7.8, ?4.1) ?mol/L in B2, and by 7.1 (95% CI: ?8.9, ?5.4) ?mol/L in B10, compared to non-significant rise of 1.2 (95% CI: ?0.5, 2.9) ?mol/L in B0. B2 and B10 did not differ significantly. In F200, tHcy fell by 4.8 (95% CI: ?6.3, ?3.3) ?mol/L compared to 2.8 (95% CI: ?4.3, ?1.2) ?mol/L in F0. Conclusion: Daily oral supplementation with physiological doses of B12 is an effective community intervention to reduce tHcy. Folic acid (200 ?g/d) showed no additional benefit, neither had any unfavourable effects. PMID:20216560

Deshmukh, Urmila S; Joglekar, Charudatta V; Lubree, Himangi G; Ramdas, Lalita V; Bhat, Dattatray S; Naik, Sadanand S; Hardikar, Pallavi S; Raut, Deepa A; Konde, Trupti B; Wills, Andrew K; Jackson, Alan A; Refsum, Helga; Nanivadekar, Arun S; Fall, Caroline H; Yajnik, Chittaranjan S

2010-01-01

273

The effect of high levels of fat, choline, vitamin B 12, and vitamin E on the occurrence of fatty livers in caged layers  

E-print Network

r?la ??l???? ??? ?ry??ra b ?? ??b???b ????? rbb? y???l?al??? ??? ??b???b ????? y?????y ??l??b ?? y??b? ???b?? ?????? ?? ?? brrbyl ?r i??i ?b?b?? ?r r?l? yi????b9 ??l???? ??? ??l???? b ?? yi??b?lb??? ??? ??l???? b 12 y??lb?l ?r b...?????? ???????? ?? ???? ?? ??? ????????? ?? ???? ?? ??? ?????????? ???????? ?? ??????????????? ?? ??? ???? ???? ? ???????? ??????? b? ??? ??????? ?????? 6? 7 ? ??? 8 ????????????? ???? ???????? ?? ????? 5 ???? ?????????????? l???? ???????? ???????? ???? ???????? ??????? b ??? ??????? ?12 ??? ????????? ??????????? ??????????????? ?? ??? ???? ?? ????? 8...

Smith, Daniel Newton

2013-10-04

274

Homocysteine, vitamin B12, and folic acid levels in Alzheimer's disease, mild cognitive impairment, and healthy elderly: baseline characteristics in subjects of the Australian Imaging Biomarker Lifestyle study.  

PubMed

There is some debate regarding the differing levels of plasma homocysteine, vitamin B12 and serum folate between healthy controls (HC), mild cognitive impairment (MCI), and Alzheimer's disease (AD). As part of the Australian Imaging Biomarker Lifestyle (AIBL) study of aging cohort, consisting of 1,112 participants (768 HC, 133 MCI patients, and 211 AD patients), plasma homocysteine, vitamin B12, and serum and red cell folate were measured at baseline to investigate their levels, their inter-associations, and their relationships with cognition. The results of this cross-sectional study showed that homocysteine levels were increased in female AD patients compared to female HC subjects (+16%, p-value < 0.001), but not in males. Red cell folate, but not serum folate, was decreased in AD patients compared to HC (-10%, p-value = 0.004). Composite z-scores of short- and long-term episodic memory, total episodic memory, and global cognition all showed significant negative correlations with homocysteine, in all clinical categories. Increasing red cell folate had a U-shaped association with homocysteine, so that high red cell folate levels were associated with worse long-term episodic memory, total episodic memory, and global cognition. These findings underscore the association of plasma homocysteine with cognitive deterioration, although not unique to AD, and identified an unexpected abnormality of red cell folate. PMID:21891867

Faux, Noel G; Ellis, Kathryn A; Porter, Lorine; Fowler, Chris J; Laws, Simon M; Martins, Ralph N; Pertile, Kelly K; Rembach, Alan; Rowe, Chris C; Rumble, Rebecca L; Szoeke, Cassandra; Taddei, Kevin; Taddei, Tania; Trounson, Brett O; Villemagne, Victor L; Ward, Vanessa; Ames, David; Masters, Colin L; Bush, Ashley I

2011-01-01

275

Electronically Excited States of Vitamin B12: Benchmark Calculations Including Time-Dependent Density Functional Theory and Correlated Ab Initio Methods  

E-print Network

Time-dependent density functional theory (TD-DFT) and correlated ab initio methods have been applied to the electronically excited states of vitamin B12 (cyanocobalamin or CNCbl). Different experimental techniques have been used to probe the excited states of CNCbl, revealing many issues that remain poorly understood from an electronic structure point of view. Due to its efficient scaling with size, TD-DFT emerges as one of the most practical tools that can be used to predict the electronic properties of these fairly complex molecules. However, the description of excited states is strongly dependent on the type of functional used in the calculations. In the present contribution, the choice of a proper functional for vitamin B12 was evaluated in terms of its agreement with both experimental results and correlated ab initio calculations. Three different functionals, i.e. B3LYP, BP86, and LC-BLYP, were tested. In addition, the effect of relative contributions of DFT and HF to the exchange-correlation functional ...

Kornobis, Karina; Wong, Bryan M; Lodowski, Piotr; Jaworska, Maria; Andruniów, Tadeusz; Rudd, Kenneth; Kozlowski, Pawel M; 10.1021/jp110914y

2011-01-01

276

Immunohistochemical Quantification of the Vitamin B12 Transport Protein (TCII), Cell Surface Receptor (TCII-R) and Ki-67 in Human Tumor Xenografts  

PubMed Central

Background/Aim Cancer cells have an essential demand for vitamin B12 (cobalamin) to enable cellular replication. The present pilot study quantified the immunohistochemical expression of vitamin B12 transport protein (Transcobalamin II; TCII), cell surface receptor (Transcobalamin II-R; TCII-R) and proliferation protein (Ki-67) in human tumor xenografts. Materials and Methods Tissue microarray slides containing 34 xenograft tumor tissues were immunohistochemically stained using TCN2 (anti-TCII), CD320 (anti-TCII-R) and MIB-1 (anti-Ki-67) antibodies. Representatively stained areas of all slides were digitally imaged and protein expression was quantified using ImageJ software plugins. Results All xenograft tumor tissues stained positively for TCII, TCII-R and Ki-67 proteins; expression varied both within and between tumor types. Correlation between TCII/TCII-R and Ki-67 expression was not significant in xenograft tissues. Conclusion Proliferating cancer cells express measurable levels of TCII and TCII-R. Immunohistochemical quantification of these markers may be useful as a tool for detection of tumors, tailored selection of anti-tumor therapies and surveillance for evidence of recurrent disease. PMID:24122983

Sysel, Annette M.; Valli, Victor E.; Nagle, Ray B.; Bauer, Joseph A.

2014-01-01

277

Metformin associated B12 deficiency.  

PubMed

According to the ADA guidelines, metformin and lifestyle modifications are the first line therapies in the treatment of type 2 diabetes mellitus. Metformin does, however, cause vitamin B-12 malabsorption, which may increase the risk of developing vitamin B-12 deficiency--a clinically important and treatable condition. Here we report a case of 60 year old diabetic male presenting with clinical features of Vitamin B-12 deficiency on long term metformin therapy, which was confirmed on investigations. Patient showed symptomatic improvement with change in treatment. PMID:22799121

Kumthekar, Anand Ajit; Gidwani, Hitesh Vinod; Kumthekar, Ajit Bhaskar

2012-03-01

278

Control of prostate cancer associated with withdrawal of a supplement containing folic acid, L-methyltetrahydrofolate and vitamin B12: a case report  

PubMed Central

Introduction This is the first report of possible direct stimulation of hormone-resistant prostate cancer or interference of docetaxel cytotoxicity of prostate cancer in a patient with biochemical relapse of prostatic-specific antigen. This observation is of clinical and metabolic importance, especially at a time when more than 80 countries have fortified food supplies with folic acid and some contemplate further fortification with vitamin B12. Case presentation Our patient is a 71-year-old Caucasian man who had been diagnosed in 1997 with prostate cancer, stage T1c, and Gleason score 3+4 = 7. His primary treatment included intermittent androgen deprivation therapy including leuprolide + bicalutamide + deutasteride, ketoconazole + hydrocortisone, nilandrone and flutamide to resistance defined as biochemical relapse of PSA. While undergoing docetaxel therapy to treat a continually increasing prostate-specific antigen level, withdrawal of 10 daily doses of a supplement containing 500 ?g of vitamin B12 as cyanocobalamin, as well as 400 ?g of folic acid as pteroylglutamic acid and 400 ?g of L-5-methyltetrahydrofolate for a combined total of 800 ?g of mixed folates, was associated with a return to a normal serum prostatic-specific antigen level. Conclusion This case report illustrates the importance of the effects of supplements containing large amounts of folic acid, L-5-methyltetrahydrofolate, and cyanocobalamin on the metabolism of prostate cancer cells directly and/or B vitamin interference with docetaxel efficacy. Physicians caring for patients with prostate cancer undergoing watchful waiting, hormone therapy, and/or chemotherapy should consider the possible acceleration of tumor growth and/or metastasis and the development of drug resistance associated with supplement ingestion. We describe several pathways of metabolic and epigenetic interactions that could affect the observed changes in serum levels of prostate-specific antigen. PMID:21867542

2011-01-01

279

The effect of vitamin B 12 and various levels of iodine in the diet of growing chicks and mature hens  

E-print Network

THF. EFFEC'I OF VITAMIN 8, , AND VARIOUS EKVK Lo OF IODINE IN THE DIET OF GBOV. ING CHICKS AND MAT URE HENS EDV ABD MACK SANTA A 'I'HgoIS oubmitted to tbe Gt aduate ochooi of tbe Agricultural and hiecbanical College of f'"xae in pertial fulf...Hhnent of tbe retlufremcnte for tbe dogree MASTER OF oCII. NCE ht a j o r oubject: sultry ociencc August 1957 'I HE E FFECT OF VITAMIN 9 . AND VABIUU& cEV E 1 o 12 OF IODINE IN THE DIET C F GI'On ING CHICKS AND MA'l UHE HENS A THEnle t DV. AND MAC K BA N...

Banta, Edward Mack

2012-06-07

280

Interrelationship of dietary vitamin B12 or fat with thyrotoxicosis in certain adaptive changes in respiratory enzymes of rat liver  

E-print Network

in the interphase. Fautrez (70 s 71) found that the DMA. content of the thy? roid of thiouracil treated rats doubled before division,. Each new daughter cell then contains normal amounts of the. nucleic, acid. DMA. synthesis in the renal tubules appeared... Bj2 deficient rats to have significantly lowered activities of liver lactic, glutamics succinic, butyric, and choline d e ? hydrogenases . They concluded that the vitamin functioned by promoting enzymic protein synthesis. A marked decrease...

Crawford, Wid Philips

2013-10-04

281

Relationship between vitamin B12, folate and homocysteine levels and H. Pylori infection in patients with functional dyspepsia: A cross-section study  

PubMed Central

Background H. pylori infection has been associated with many micronutrient deficiencies. There is a dearth of data from communities with nutritional deficiencies and high prevalence of H. pylori infection. The aim of this study was to determine the impact of H. pylori infection on serum levels of vitamin B12, folate and homocysteine in patients with functional dyspepsia (FD). Methods One hundred and thirty-two patients with FD undergoing gastroscopy were enrolled. The serum was analyzed for B12, folate and homocysteine levels before gastroscopy. H. pylori infection was diagnosed by histopathological examination of gastric biopsies and urea breath test. An independent sample t-test and the Mann–Whitney test were used to compare mean serum concentrations of biomarkers between H. pylori-positive and H. pylori-negative groups of patients. A Chi-square test was performed to assess the differences among proportions, while Spearman’s rho was used for correlation analysis between levels of B12 and homocysteine. Results The mean age of the group was 40.3?±?11.5 (19–72) years. Folate deficiency was seen in 43 (34.6%), B12 deficiency in 30 (23.1%) and hyperhomocysteinemia in 60 (46.2%) patients. H. pylori was present in 80 (61.5%) patients with FD while it was absent in 50 (38.5%). Mean serum levels of B12, folate and homocysteine in the H. pylori-positive group of patients were not significantly different from the levels in the H. pylori-negative group (357?±?170 vs. 313?±?136?pg/mL; p?=?0.13), (4.35?±?1.89 vs. 4.42?±?1.93?ng/mL; p?=?0.84); (15.88?±?8.97 vs. 16.62?±?7.82??mol/L; p?=?0.24); respectively. B12 deficiency (?200?pg/mL) was 23.8% in the H. pylori-positive patients versus 22.0% in the H. pylori-negative patients. Folate deficiency (?3.5?ng/mL) was 33.8% in the H. pylori-positive group versus 36% in the H. pylori-negative group. Hyperhomocysteinemia (>15??mol/L) was present in 46.2% of H. pylori-positive patients compared to 44% in the H. pylori-negative group. Correlation analysis indicated that serum B12 levels were inversely associated with serum levels of homocysteine in patients with FD (rho?=??0.192; p?=?0.028). Conclusions This study demonstrated an inverse relationship between serum levels of B12 and homocysteine in patients with FD. Moreover, no impact of the presence of H. pylori was found on B12, folate and homocysteine levels in such patients. PMID:22546014

2012-01-01

282

Vitamin B12, antibiotics and unidentified factors in the nutrition of the turkey poult and mature chicken  

E-print Network

on the Intestinal flora of the fowl. When these facts were considered it seemed desirable to determine the effect oi' several antibiotics when tested undez' the same conditions on the growth rate in the turkey poult. Since the mode of action of these substances... that glycine could be converted irrevers- 1bly in the presence of folic acid to formic acid and the formic acid, in the presence of vitamin Bi&, could he converted to either methionine or choline. Patrick ( 'SO) found a close relationship between methionine...

Reid, Bobby Leroy

2012-06-07

283

Drug release profiles and microstructural characterization of cast and freeze dried vitamin B12 buccal films by positron annihilation lifetime spectroscopy.  

PubMed

Solvent cast and freeze dried films, containing the water-soluble vitamin B12 as model drug were prepared from two polymers, sodium alginate (SA), and Carbopol 71G (CP). The proportion of the CP was changed in the films. The microstructural characterization of various samples was carried out by positron annihilation lifetime spectroscopy (PALS). The drug release kinetics of untreated and stored samples was evaluated by the conventionally applied semi-empirical power law. Correlation was found between the changes of the characteristic parameters of the drug release and the ortho-positronium (o-Ps) lifetime values of polymer samples. The results indicated that the increase of CP concentration, the freeze-drying process and the storage at 75% R.H. decreased the rate of drug release. The PALS method enabled the distinction between the micro- and macrostructural factors influencing the drug release profile of polymer films. PMID:24269613

Szabó, Barnabás; Kállai, Nikolett; Tóth, Gerg?; Hetényi, Gergely; Zelkó, Romána

2014-02-01

284

In vitro release studies of vitamin B 12 from poly N-vinyl pyrrolidone/starch hydrogels grafted with acrylic acid synthesized by gamma radiation  

NASA Astrophysics Data System (ADS)

Co-polymeric hydrogels containing N-vinyl pyrrolidone and starch grafted with acrylic acid were synthesized by gamma radiation to be used as drug delivery system. Their gel contents, grafting swelling and thermal gravimetric analysis were evaluated. The gel content increases by increasing the irradiation dose up to 50 kGy, then decreases. The grafting percent increases by the increasing of acrylic acid. The thermal stability and the rate of the thermal decomposition changed according to the different compositions. The maximum rate of the thermal decomposition decreases by increasing the irradiation dose from 20 to 30 kGy and increases by increasing the irradiation dose from 30 to 70 kGy. The hydrogels loaded with vitamin B 12 demonstrated a decrease release in acidic medium than the neutral one.

Eid, M.

2008-12-01

285

Late onset of symptoms in an atypical patient with the cblJ inborn error of vitamin B12 metabolism: diagnosis and novel mutation revealed by exome sequencing.  

PubMed

Inborn errors of vitamin B(12) (cobalamin) metabolism are characterized by decreased production of active cobalamin cofactors and subsequent deficiencies in the activities of methionine synthase and methylmalonyl-CoA mutase. With the recent discovery of the cblJ defect in two patients with phenotypes mimicking the cblF defect, there are nine genes known to be involved in cobalamin metabolism. The new defect is caused by mutations in the ABCD4 gene, encoding an ABC transporter. At the moment, there is no clear distinction between the cblJ and cblF defects either clinically or biochemically, and both defects result in blocks in the transport of cobalamin from the lysosome to the cytoplasm. A patient was diagnosed with hyperhomocysteinemia and methylmalonic aciduria at the age of 8 years. Incorporations of both [(14)C]propionate and [(14)C]methyltetrahydrofolate in cultured fibroblasts were within reference ranges and thus too high to allow for complementation analysis. We observed decreased synthesis of both adenosylcobalamin and methylcobalamin and accumulation of unmetabolized cyanocobalamin. Exome sequencing was performed to identify causative mutation(s) and Sanger re-sequencing was performed to validate segregation of mutation in the family. By this approach, a homozygous mutation, c.423C>G, in the ABCD4 gene was identified. Here, we report the successful application of exome sequencing for diagnosis of a rare inborn error of vitamin B(12) metabolism in a patient whose unusual presentation precluded diagnosis using standard biochemical and genetic approaches. The patient represents only the third known patient with the cblJ disorder. PMID:23141461

Kim, Jaeseung C; Lee, Ni-Chung; Hwu, Paul Wuh-Liang; Chien, Yin-Hsiu; Fahiminiya, Somayyeh; Majewski, Jacek; Watkins, David; Rosenblatt, David S

2012-12-01

286

Navigating the B12 Road: Assimilation, Delivery, and Disorders of Cobalamin*  

PubMed Central

The reactivity of the cobalt-carbon bond in cobalamins is the key to their chemical versatility, supporting both methyl transfer and isomerization reactions. During evolution of higher eukaryotes that utilize vitamin B12, the high reactivity of the cofactor coupled with its low abundance pressured development of an efficient system for uptake, assimilation, and delivery of the cofactor to client B12-dependent enzymes. Although most proteins suspected to be involved in B12 trafficking were discovered by 2009, the recent identification of a new protein reveals that the quest for elucidating the intracellular B12 highway is still far from complete. Herein, we review the biochemistry of cobalamin trafficking. PMID:23539619

Gherasim, Carmen; Lofgren, Michael; Banerjee, Ruma

2013-01-01

287

Dietary Intake of Folate, but not Vitamin B 2 or B 12 , Is Associated with Increased Bone Mineral Density 5 Years after the Menopause: Results from a 10Year Follow-Up Study in Early Postmenopausal Women  

Microsoft Academic Search

Folate, vitamin B2 (riboflavin), and vitamin B12 may affect bone directly or through an effect on plasma homocysteine levels. Previously, a positive association has been found\\u000a between plasma levels and bone mineral density (BMD) as well as risk of fracture. However, there are limited data on whether\\u000a dietary intakes affect bone. Our aim was to investigate whether intake of folate,

L. Rejnmark; P. Vestergaard; A. P. Hermann; C. Brot; P. Eiken; L. Mosekilde

2008-01-01

288

Reversed-phase high-performance liquid chromatography method with coulometric electrochemical and ultraviolet detection for the quantification of vitamins B 1 (thiamine), B 6 (pyridoxamine, pyridoxal and pyridoxine) and B 12 in animal and plant foods  

Microsoft Academic Search

A rapid and sensitive high-performance liquid chromatography (HPLC) method with coulometric electrochemical and ultraviolet detections for analysis of vitamin B (B1, B6 and B12) in animal and plant foods has been developed. A combination of acid digestion and enzymatic extraction to release protein bound and phosphorylated vitamins followed by HPLC analysis was applied. The analyses were carried out on a

Anna Lebiedzi?ska; Marcin Leszek Marsza??; Jadwiga Kuta; Piotr Szefer

2007-01-01

289

Folic acid and vitamin B12 are more effective than vitamin B6 in lowering fasting plasma homocysteine concentration in patients with coronary artery disease  

Microsoft Academic Search

Objective: To investigate whether vitamin B6 supplementation had a beneficial effect on lowering fasting plasma homocysteine concentrations in coronary artery disease (CAD) patients.Design: A single-blind intervention study.Setting: The study was performed at the Taichung Veterans General Hospital, the central part of Taiwan.Subjects: A total of 50 subjects were identified by cardiac catheterization to have at least 70% stenosis of one

B-J Lee; M-C Huang; L-J Chung; C-H Cheng; K-L Lin; K-H Su; Y-C Huang

2004-01-01

290

STRA6 is critical for cellular vitamin A uptake and homeostasis.  

PubMed

Vitamin A must be adequately distributed within the body to maintain the functions of retinoids in the periphery and chromophore production in the eyes. Blood transport of the lipophilic vitamin is mediated by the retinol-binding protein, RBP4. Biochemical evidence suggests that cellular uptake of vitamin A from RBP4 is facilitated by a membrane receptor. This receptor, identified as the Stimulated by retinoic acid gene 6 (Stra6) gene product, is highly expressed in epithelia that constitute blood-tissue barriers. Here we established a Stra6 knockout mouse model to analyze the metabolic basis of vitamin A homeostasis in peripheral tissues. These mice were viable when bred on diets replete in vitamin A, but evidenced markedly reduced levels of ocular retinoids. Ophthalmic imaging and histology revealed malformations in the choroid and retinal pigmented epithelium, early cone photoreceptor cell death, and reduced lengths of rod outer segments. Similar to the blood-retina barrier in the RPE, vitamin A transport through the blood-cerebrospinal fluid barrier in the brain's choroid plexus was impaired. Notably, treatment with pharmacological doses of vitamin A restored vitamin A transport across these barriers and rescued the vision of Stra6(-/-) mice. Furthermore, under conditions mimicking vitamin A excess and deficiency, our analyses revealed that STRA6-mediated vitamin A uptake is a regulated process mandatory for ocular vitamin A uptake when RBP4 constitutes the only transport mode in vitamin A deficiency. These findings identifying STRA6 as a bona fide vitamin A transporter have important implications for disease states associated with impaired blood vitamin A homeostasis. PMID:24852372

Amengual, Jaume; Zhang, Ning; Kemerer, Mary; Maeda, Tadao; Palczewski, Krzysztof; Von Lintig, Johannes

2014-10-15

291

The prevalence of low serum vitamin B-12 status in the absence of anemia or macrocytosis did not increase among older U.S. adults after mandatory folic acid fortification.  

PubMed

Whether folic acid fortification and supplementation at the population level have led to a higher prevalence of vitamin B-12 deficiency in the absence of anemia remains to be examined among a nationally representative sample of older U.S. adults. We assessed the prevalence of low vitamin B-12 status in the absence of anemia or macrocytosis before and after fortification among adults aged >50 y using cross-sectional data from the NHANES 1991-1994 (prefortification) and 2001-2006 (postfortification). We compared the prefortification and postfortification prevalence of multiple outcomes, including serum vitamin B-12 deficiency (<148 pmol/L) and marginal deficiency (148-258 pmol/L) with and without anemia (hemoglobin <130 g/L for men, <120 g/L for women) and with and without macrocytosis (mean cell volume >100 fL) using multinomial logistic regression, adjusting for age, sex, ethnicity, body mass index, C-reactive protein, and vitamin B-12 supplement use. Prefortification and postfortification serum vitamin B-12 deficiency without anemia [4.0 vs. 3.9%; adjusted prevalence ratio (aPR) (95% CI): 0.98 (0.67, 1.44)] or without macrocytosis [4.2 vs. 4.1%; aPR (95% CI): 0.96 (0.65, 1.43)] remained unchanged. Marginal deficiency without anemia [25.1 vs. 20.7%; aPR (95% CI): 0.82 (0.72, 0.95)] or without macrocytosis [25.9 vs. 21.3%; aPR (95% CI): 0.82 (0.72, 0.94)] were both significantly lower after fortification. After fortification, higher folic acid intake was associated with a lower prevalence of low serum B-12 status in the absence of anemia or macrocytosis. Results suggest that the prevalence of low serum B-12 status in the absence of anemia or macrocytosis among older U.S. adults did not increase after fortification. Thus, at the population level, we found no evidence to support concerns that folic acid adversely affected the clinical presentation of vitamin B-12 deficiency among older adults. PMID:24306216

Qi, Yan Ping; Do, Ann N; Hamner, Heather C; Pfeiffer, Christine M; Berry, Robert J

2014-02-01

292

Methyl Vitamin B12 but not methylfolate rescues a motor neuron-like cell line from homocysteine-mediated cell death  

SciTech Connect

Homocysteine is an excitatory amino acid implicated in multiple diseases including amyotrophic lateral sclerosis (ALS). Information on the toxicity of homocysteine in motor neurons is limited and few studies have examined how this toxicity can be modulated. In NSC-34D cells (a hybrid cell line derived from motor neuron-neuroblastoma), homocysteine induces apoptotic cell death in the millimolar range with a TC{sub 50} (toxic concentration at which 50% of maximal cell death is achieved) of 2.2 mM, confirmed by activation of caspase 3/7. Induction of apoptosis was independent of short-term reactive oxygen species (ROS) generation. Methyl Vitamin B12 (MeCbl) and methyl tetrahydrofolate (MTHF), used clinically to treat elevated homocysteine levels, were tested for their ability to reverse homocysteine-mediated motor neuron cell death. MeCbl in the micromolar range was able to provide neuroprotection (2 h pretreatment prior to homocysteine) and neurorescue (simultaneous exposure with homocysteine) against millimolar homocysteine with an IC{sub 50} (concentration at which 50% of maximal cell death is inhibited) of 0.6 {mu}M and 0.4 {mu}M, respectively. In contrast, MTHF (up to 10 {mu}M) had no effect on homocysteine-mediated cell death. MeCbl inhibited caspase 3/7 activation by homocysteine in a time- and dose-dependent manner, whereas MTHF had no effect. We conclude that MeCbl is effective against homocysteine-induced cell death in motor neurons in a ROS-independent manner, via a reduction in caspase activation and apoptosis. MeCbl decreases Hcy induced motor neuron death in vitro in a hybrid cell line derived from motor neuron-neuroblastoma and may play a role in the treatment of late stage ALS where HCy levels are increased in animal models of ALS.

Hemendinger, Richelle A., E-mail: richelle.hemendinger@carolinashealthcare.org; Armstrong, Edward J.; Brooks, Benjamin Rix

2011-03-15

293

Relationship between methylmalonic acid, homocysteine, vitamin B12 intake and status and socio-economic indices, in a subset of participants in the British National Diet and Nutrition Survey of people aged 65 y and over  

Microsoft Academic Search

Objective: Assessment of functional vitamin B12 status in a subset of the respondents in the British National Diet and Nutrition Survey of people aged 65 y and over.Setting: National Diet and Nutrition Survey: a British nationwide cross-sectional sample of people aged 65 y and over, living either in the community or in institutions such as nursing homes, during one calendar

C J Bates; J Schneede; G Mishra; A Prentice; M A Mansoor

2003-01-01

294

Calcidiol and vitamin D binding protein uptake by LLC-PK/sub 1/ cells  

SciTech Connect

The process by which target cells take up vitamin D and its metabolites is not known. The authors studied the uptake of both /sup 3/H-calcidiol and /sup 125/I-Vitamin D Binding Protein (DBP) by LLC-PK/sub 1/ cells. Uptake was directly related to their extracellular concentrations. In the presence of 55 serum in the growth media cells previously incubated with 10 nM calcitriol for 4 hr had a greater uptake of calcidiol than those cells not incubated with calcitriol. This effect of calcitriol on calcidiol uptake was absent when cells were grown in hormone-supplemented, serum-free media, despite these cells having a cytosolic calcitriol receptor. Equal uptake of calcidiol occurred when DBP was absent and when DBP was present in a one to one molar ratio to calcidiol. With a 1:1 ratio of DBP to calcidiol and a measured K/sub D/ of 2 x 10/sup -8/M, the uptake of calcidiol could not be accounted for by uptake of the free ligand alone. A large excess of DBP (100:1) in relation to calcidiol suppressed uptake of calcidiol by approx. 90%. The authors have not been able to identify a saturable, specific uptake of either calcidiol or DBP despite DBP appearing to facilitate calcidiol uptake.

Keenan, M.J.; Holmes, R.P.

1986-03-01

295

Changes in uptake of vitamin B 12 and trace metals in brains of mice treated with clioquinol  

Microsoft Academic Search

Clioquinol is a hydroxyquinoline antibiotic that has been associated with severe side-effects in the CNS. The syndrome caused by clioquinol treatment, subacute myelo-optic neuropathy (SMON), is considered as one of the worst drug disasters of this century. The precise biochemical mechanism behind SMON is not fully understood. Clioquinol can form strong lipophilic chelates with divalent cations and therefore it has

M. S. Yassin; J. Ekblom; M. Xilinas; C. G. Gottfries; L. Oreland

2000-01-01

296

Preferential uptake and accumulation of oxidized vitamin C by THP-1 monocytic cells.  

PubMed

THP-1 cells preferentially accumulate vitamin C in its oxidized form. The uptake displays first-order kinetics and leads to a build-up of an outward concentration gradient which is stable in the absence of extracellular vitamin. The transport is faster than reduction by extracellular glutathione or by added cytosolic extract, and glutathione-depleted cells show the same uptake rates as control cells. In addition, energy depletion or oxidation of intracellular sulfhydryls does not inhibit accumulation of ascorbate. The accumulation, however, always occurs in the reduced form. The affinity for dehydroascorbate is lower (Km 450 microM vs 60 microM) than for reduced ascorbate, but the maximal rate is more than 30 times higher (581 compared to 19 pmol.min-1 per 106 cells), and it is independent of sodium, whereas the uptake of ascorbate is not. The sodium gradient also allows accumulation of reduced ascorbate. Inhibitors of glucose transport by the GLUT-1 transporter also inhibit uptake of dehydroascorbate (DHA), but there are some inconsistencies, because the Ki-values are higher than reported for the isolated transporter and one inhibitor (deoxyglucose) is noncompetitive. The preferential uptake of the dehydro-form of the vitamin may be useful for situations where this short-lived metabolite is formed by oxidation in the environment. PMID:10411625

Laggner, H; Besau, V; Goldenberg, H

1999-06-01

297

On the Mechanism of Action of Vitamin B12. Model Studies. Thermal Rearrangement of Methyl 3,3-Dimethylglycidate to Methyl Levulinate  

PubMed Central

The discovery that methyl 3,3-dimethylglycidate rearranges to methyl levulinate on heating is discussed in terms of its possible consequences for the mechanism of action of the coenzyme B12-dependent enzymes: methylmalonyl-CoA mutase (EC 5.4.99.2), glutamate mutase (EC 5.4.99.1), and a-methyleneglutarate mutase. It is also suggested that the proposed mechanism may provide a unifying link between the mechanism of action of the above enzymes and that of the coenzyme B12-dependent dioldehydrase and related enzymes. PMID:4504332

Dowd, Paul; Nakagawa, Christopher S.

1972-01-01

298

An optimized method for the simultaneous determination of vitamins B 1, B 6, B 12, in multivitamin tablets by high performance liquid chromatography  

Microsoft Academic Search

A simple, precise, rapid and selective HPLC-RP method has been developed for the simultaneous determination of thiamine hydrochloride (B1) 150 mg, pyridoxine hydrochloride (B6) 150 mg, and hydroxocobalamine chloride (B12) 0.150 mg in multivitamin tablets. The method uses a Hypersil-BDS C18 reversed phase column and gradient elution. The aqueous mobile phase contained 0.015% triethylamine adjusted to pH 2.7 with 1

C. K Markopoulou; K. A Kagkadis; J. E Koundourellis

2002-01-01

299

Effect of the methylenetetrahydrofolate reductase gene polymorphisms on homocysteine, folate and vitamin B12 in patients with bipolar disorder and relatives  

Microsoft Academic Search

We investigated the effect of polymorphic variants of c.1298A>C (Glu429Ala) and c.677C>T (Ala222Val) in methylenetetrahydrofolate (MTHFR) gene on the total homocysteine (tHcy), folate and B12 levels in patients with bipolar disorder, first-degree relatives of patients, and controls. The c.677C>T and c.1298A>C polymorphisms in MTHFR were determined by polymerase chain reaction-restriction fragment length polymorphism in 197 bipolar patients, 278 relatives and

Zeynep Ozbek; Cem Ismail Kucukali; Elif Ozkok; Nurcan Orhan; Makbule Aydin; Gamze Kilic; Ali Sazci; Ihsan Kara

2008-01-01

300

The 380 kb pCMU01 plasmid encodes chloromethane utilization genes and redundant genes for vitamin B12- and tetrahydrofolate-dependent chloromethane metabolism in Methylobacterium extorquens CM4: a proteomic and bioinformatics study.  

PubMed

Chloromethane (CH3Cl) is the most abundant volatile halocarbon in the atmosphere and contributes to the destruction of stratospheric ozone. The only known pathway for bacterial chloromethane utilization (cmu) was characterized in Methylobacterium extorquens CM4, a methylotrophic bacterium able to utilize compounds without carbon-carbon bonds such as methanol and chloromethane as the sole carbon source for growth. Previous work demonstrated that tetrahydrofolate and vitamin B12 are essential cofactors of cmuA- and cmuB-encoded methyltransferases of chloromethane dehalogenase, and that the pathway for chloromethane utilization is distinct from that for methanol. This work reports genomic and proteomic data demonstrating that cognate cmu genes are located on the 380 kb pCMU01 plasmid, which drives the previously defined pathway for tetrahydrofolate-mediated chloromethane dehalogenation. Comparison of complete genome sequences of strain CM4 and that of four other M. extorquens strains unable to grow with chloromethane showed that plasmid pCMU01 harbors unique genes without homologs in the compared genomes (bluB2, btuB, cobA, cbiD), as well as 13 duplicated genes with homologs of chromosome-borne genes involved in vitamin B12-associated biosynthesis and transport, or in tetrahydrofolate-dependent metabolism (folC2). In addition, the presence of both chromosomal and plasmid-borne genes for corrinoid salvaging pathways may ensure corrinoid coenzyme supply in challenging environments. Proteomes of M. extorquens CM4 grown with one-carbon substrates chloromethane and methanol were compared. Of the 49 proteins with differential abundance identified, only five (CmuA, CmuB, PurU, CobH2 and a PaaE-like uncharacterized putative oxidoreductase) are encoded by the pCMU01 plasmid. The mainly chromosome-encoded response to chloromethane involves gene clusters associated with oxidative stress, production of reducing equivalents (PntAA, Nuo complex), conversion of tetrahydrofolate-bound one-carbon units, and central metabolism. The mosaic organization of plasmid pCMU01 and the clustering of genes coding for dehalogenase enzymes and for biosynthesis of associated cofactors suggests a history of gene acquisition related to chloromethane utilization. PMID:23593113

Roselli, Sandro; Nadalig, Thierry; Vuilleumier, Stéphane; Bringel, Françoise

2013-01-01

301

Differential Regulation of Hepatic Transcription Factors in the Wistar Rat Offspring Born to Dams Fed Folic Acid, Vitamin B12 Deficient Diets and Supplemented with Omega-3 Fatty Acids  

PubMed Central

Nutritional status of the mother is known to influence various metabolic adaptations required for optimal fetal development. These may be mediated by transcription factors like peroxisome proliferator activated receptors (PPARs), which are activated by long chain polyunsaturated fatty acids. The objective of the current study was to examine the expression of different hepatic transcription factors and the levels of global methylation in the liver of the offspring born to dams fed micronutrient deficient (folic acid and vitamin B12) diets and supplemented with omega-3 fatty acids. Female rats were divided into five groups (n?=?8/group) as follows; control, folic acid deficient (FD), vitamin B12 deficient (BD) and omega-3 fatty acid supplemented groups (FDO and BDO). Diets were given starting from pre-conception and continued throughout pregnancy and lactation. Pups were dissected at the end of lactation. Liver tissues were removed; snap frozen and stored at ?80°C. Maternal micronutrients deficiency resulted in lower (p<0.05) levels of pup liver docosahexaenoic acid (DHA) and arachidonic acid (ARA) as compared to the control group. Pup liver PPAR? and PPAR? expression was lower (p<0.05) in the BD group although there were no differences in the expression of SREBP-1c, LXR? and RXR? expression. Omega-3 fatty acids supplementation to this group normalized (p<0.05) levels of both PPAR? and PPAR? but reduced (p<0.05) SREBP-1c, LXR? and RXR? expression. There was no change in any of the transcription factors in the pup liver in the FD group. Omega-3 fatty acids supplementation to this group reduced (p<0.05) PPAR?, SREBP-1c and RXR? expression. Pup liver global methylation levels were higher (p<0.01) in both the micronutrients deficient groups and could be normalized (p<0.05) by omega-3 fatty acid supplementation. Our novel findings suggest a role for omega-3 fatty acids in the one carbon cycle in influencing the hepatic expression of transcription factors in the offspring. PMID:24587285

Meher, Akshaya; Joshi, Asmita; Joshi, Sadhana

2014-01-01

302

Vitamin B12 als biologisch aktive Modellsubstanz  

NASA Astrophysics Data System (ADS)

A critical review on corrinoid biochemistry and physiology is presented. This includes: chemical synthesis of biologically important organocorrinoids and the correlation between their structures and coenzymatic activity; forms, distribution and transport of physiologically active corrinoids; methylcobalamin- and adenosylcobalamin-dependent enzymatic reactions and their physiological functions; and steric course of the adenosylcobalamin-dependent enzymatic rearrangements. Special attention is paid to the mechanisms of adenosylcobalamin-dependent enzymatic reactions.

Zagalak, Boles?aw

1982-02-01

303

Uptake of 75Se-selenite by brush border membrane vesicles from chick duodenum stimulated by vitamin D.  

PubMed

Brush border membrane vesicles were isolated from mucosal homogenates of duodena from normal, rachitic and vitamin D-treated rachitic chicks using a discontinuous sucrose gradient, and further purified by glycerol gradient centrifugation. In vitro uptake of 75Se-selenite by purified brush border membrane vesicles was studied using a rapid filtration technique. The time course of 75Se uptake was non-linear; rapid initial binding was followed by a gradual decrease in the rate of uptake until an equilibrium value was reached at 60-120 min. The initial binding at 36 s was not affected by selenite concentration in the incubation buffer, while the fractional rate of uptake between the 36 s and 2 min time periods was clearly lower with 1 mM Se than with 4-100 microM Se. 75Se uptake did not show any dependency on the external Na-gradient, nor could it be inhibited by other anions (arsenate, phosphate). Treatment of rachitic chicks either with cholecalciferol (500 Iu, 72 h) or with 1,25(OH)2-cholecalciferol (0.5 microgram given 16 h prior to isolation of the vesicles) significantly enhanced 75Se uptake. A threefold excess of mannitol in the outside buffer reduced 75Se uptake by vesicles from vitamin D-deficient and D-treated chicks 60% and 35% respectively, but had no effect on vesicles from vitamin D-treated chicks preloaded with 75Se. Neither saponin treatment nor excess cold selenite could release the label from the vesicles preloaded with 75Se. These data are compatible with the hypothesis that selenite easily crosses the brush border membrane into the intravesicular space and, once inside, is tightly bound by the membrane.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2493081

Mykkanen, H M; Wasserman, R H

1989-02-01

304

Uptake of /sup 75/Se-selenite by brush border membrane vesicles from chick duodenum stimulated by vitamin D  

SciTech Connect

Brush border membrane vesicles were isolated from mucosal homogenates of duodena from normal, rachitic and vitamin D-treated rachitic chicks using a discontinuous sucrose gradient, and further purified by glycerol gradient centrifugation. In vitro uptake of 75Se-selenite by purified brush border membrane vesicles was studied using a rapid filtration technique. The time course of 75Se uptake was non-linear; rapid initial binding was followed by a gradual decrease in the rate of uptake until an equilibrium value was reached at 60-120 min. The initial binding at 36 s was not affected by selenite concentration in the incubation buffer, while the fractional rate of uptake between the 36 s and 2 min time periods was clearly lower with 1 mM Se than with 4-100 microM Se. 75Se uptake did not show any dependency on the external Na-gradient, nor could it be inhibited by other anions (arsenate, phosphate). Treatment of rachitic chicks either with cholecalciferol (500 Iu, 72 h) or with 1,25(OH)2-cholecalciferol (0.5 microgram given 16 h prior to isolation of the vesicles) significantly enhanced 75Se uptake. A threefold excess of mannitol in the outside buffer reduced 75Se uptake by vesicles from vitamin D-deficient and D-treated chicks 60% and 35% respectively, but had no effect on vesicles from vitamin D-treated chicks preloaded with 75Se. Neither saponin treatment nor excess cold selenite could release the label from the vesicles preloaded with 75Se. These data are compatible with the hypothesis that selenite easily crosses the brush border membrane into the intravesicular space and, once inside, is tightly bound by the membrane.

Mykkanen, H.M.; Wasserman, R.H.

1989-02-01

305

Biochemistry of B12-cofactors in human metabolism.  

PubMed

Vitamin B12, the "antipernicious anaemia factor", is a crystallisable cobalt-complex, which belongs to a group of unique "complete" corrinoids, named cobalamins (Cbl). In humans, instead of the "vitamin", two organometallic B12-forms are coenzymes in two metabolically important enzymes: Methyl-cobalamin, the cofactor of methionine synthase, and coenzyme B12 (adenosyl-cobalamin), the cofactor of methylmalonyl-CoA mutase. The cytoplasmatic methionine synthase catalyzes the transfer of a methyl group from N-methyl-tetrahydrofolate to homocysteine to yield methionine and to liberate tetrahydrofolate. In the mitochondrial methylmalonyl-CoA mutase a radical process transforms methylmalonyl-CoA (a remains e.g. from uneven numbered fatty acids) into succinyl-CoA, for further metabolic use. In addition, in the human mitochondria an adenosyl-transferase incorporates the organometallic group of coenzyme B12. In all these enzymes, the bound B12-derivatives engage (or are formed) in exceptional organometallic enzymatic reactions. This chapter recapitulates the physiological chemistry of vitamin B12, relevant in the context of the metabolic transformation of B12-derivatives into the relevant coenzyme forms and their use in B12-dependent enzymes. PMID:22116707

Kräutler, Bernhard

2012-01-01

306

A Membrane Receptor for Retinol Binding Protein Mediates Cellular Uptake of Vitamin A  

Microsoft Academic Search

Vitamin A has diverse biological functions. It is transported in the blood as a complex with retinol binding protein (RBP), but the molecular mechanism by which vitamin A is absorbed by cells from the vitamin A-RBP complex is not clearly understood. We identified in bovine retinal pigment epithelium cells STRA6, a multitransmembrane domain protein, as a specific membrane receptor for

Riki Kawaguchi; Jiamei Yu; Jane Honda; Jane Hu; Julian Whitelegge; Peipei Ping; Patrick Wiita; Dean Bok; Hui Sun

2007-01-01

307

Nitric oxide negatively regulates AKT1-mediated potassium uptake through modulating vitamin B6 homeostasis in Arabidopsis.  

PubMed

Nitric oxide (NO), an active signaling molecule in plants, is involved in numerous physiological processes and adaptive responses to environmental stresses. Under high-salt conditions, plants accumulate NO quickly, and reorganize Na(+) and K(+) contents. However, the molecular connection between NO and ion homeostasis is largely unknown. Here, we report that NO lowers K(+) channel AKT1-mediated plant K(+) uptake by modulating vitamin B6 biosynthesis. In a screen for Arabidopsis NO-hypersensitive mutants, we isolated sno1 (sensitive to nitric oxide 1), which is allelic to the previously noted mutant sos4 (salt overly sensitive 4) that has impaired Na(+) and K(+) contents and overproduces pyridoxal 5'-phosphate (PLP), an active form of vitamin B6. We showed that NO increased PLP and decreased K(+) levels in plant. NO induced SNO1 gene expression and enzyme activity, indicating that NO-triggered PLP accumulation mainly occurs through SNO1-mediated vitamin B6 salvage biosynthetic pathway. Furthermore, we demonstrated that PLP significantly repressed the activity of K(+) channel AKT1 in the Xenopus oocyte system and Arabidopsis root protoplasts. Together, our results suggest that NO decreases K(+) absorption by promoting the synthesis of vitamin B6 PLP, which further represses the activity of K(+) channel AKT1 in Arabidopsis. These findings reveal a previously unidentified pivotal role of NO in modulating the homeostasis of vitamin B6 and potassium nutrition in plants, and shed light on the mechanism of NO in plant acclimation to environmental changes. PMID:25355908

Xia, Jinchan; Kong, Dongdong; Xue, Shaowu; Tian, Wang; Li, Nan; Bao, Fang; Hu, Yong; Du, Jing; Wang, Yu; Pan, Xiaojun; Wang, Lei; Zhang, Xiaochen; Niu, Guoqi; Feng, Xue; Li, Legong; He, Yikun

2014-11-11

308

Sodium ascorbate (vitamin C) induces apoptosis in melanoma cells via the down-regulation of transferrin receptor dependent iron uptake.  

PubMed

Sodium ascorbate (vitamin C) has a reputation for inconsistent effects upon malignant tumor cells, which vary from growth stimulation to apoptosis induction. Melanoma cells were found to be more susceptible to vitamin C toxicity than any other tumor cells. The present study has shown that sodium ascorbate decreases cellular iron uptake by melanoma cells in a dose- and time-dependent fashion, indicating that intracellular iron levels may be a critical factor in sodium ascorbate-induced apoptosis. Indeed, sodium ascorbate-induced apoptosis is enhanced by the iron chelator, desferrioxamine (DFO) while it is inhibited by the iron donor, ferric ammonium citrate (FAC). Moreover, the inhibitory effects of sodium ascorbate on intracellular iron levels are blocked by addition of transferrin, suggesting that transferrin receptor (TfR) dependent pathway of iron uptake may be regulated by sodium ascorbate. Cells exposed to sodium ascorbate demonstrated down-regulation of TfR expression and this precedes sodium ascorbate-induced apoptosis. Taken together, sodium ascorbate-mediated apoptosis appears to be initiated by a reduction of TfR expression, resulting in a down-regulation of iron uptake followed by an induction of apoptosis. This study demonstrates the specific mechanism of sodium ascorbate-induced apoptosis and these findings support future clinical trial of sodium ascorbate in the prevention of human melanoma relapse. PMID:15672419

Kang, Jae Seung; Cho, Daeho; Kim, Young-In; Hahm, Eunsil; Kim, Yeong Seok; Jin, Shun Nu; Kim, Ha Na; Kim, Daejin; Hur, Daeyoung; Park, Hyunjeong; Hwang, Young Il; Lee, Wang Jae

2005-07-01

309

Uptake of (/sup 3/H)vitamin D/sub 3/ from low and high density lipoproteins by cultured human fibroblasts  

SciTech Connect

The plasma distribution and cellular uptake of (/sup 3/H)vitamin D/sub 3/ was studied in vitro using cultured human fibroblasts. Incubation of (/sup 3/H)vitamin D/sub 3/ (cholecalciferol) with plasma followed by sequential ultracentrifugal fractionation of the lipoproteins indicated that 2-4% of the radioactivity associated with the very low density lipoprotein (VLDL), 12% with low density lipoprotein (LDL), and approximately 60% with the high density lipoprotein (HDL). The remaining radioactivity, 25%, was associated with the sedimented plasma fractions. By comparison, an average of 86% of the radioactivity from (/sup 3/H) 1,25-dihydroxycholecalciferol associated with the sedimented plasma fractions. The uptake of (/sup 3/H)vitamin D/sub 3/ from plasma, LDL, or HDL was studied in cultured human cells; uptake by normal fibroblasts was greatest from LDL and least from plasma. The cellular association of vitamin D/sub 3/ was time, concentration, and temperature dependent. At a concentration of 50 ..mu..g LDL/ml of medium, the uptake of (/sup 3/H)vitamin D/sub 3/ from LDL at 37/sup 0/C was rapid and reached a maximum at approximately 4 hr; it was slower from HDL but continued to increase slowly up to 24 hr. The significance of these in vitro findings is uncertain since much of the vitamin D/sub 3/ absorbed from the intestine reportedly associates with chylomicrons and is rapidly taken up by the liver.

Shireman, R.B.; Williams, D.; Remsen, J.F.

1986-03-01

310

Hydrosoluble vitamins.  

PubMed

The hydrosoluble vitamins are a group of organic substances that are required by humans in small amounts to prevent disorders of metabolism. Significant progress has been made in our understanding of the biochemical, physiologic and nutritional aspects of the water-soluble vitamins. Deficiency of these particular vitamins, most commonly due to inadequate nutrition, can result in disorders of the nervous system. Many of these disorders have been successfully prevented in developed countries; however, they are still common in developing countries. Of the hydrosoluble vitamins, the nervous system depends the most on vitamins B and C (ascorbic acid) for proper functioning. The B group vitamins include thiamin (vitamin B1), riboflavin (vitamin B2), niacin or niacinamide (vitamin B3), pantothenic acid (vitamin B5), pyridoxine or pyridoxal (vitamin B6) and cobalamin (vitamin B12). Clinical findings depend upon the deficiency of the underlying vitamin; generally, deficiency symptoms are seen from a combination rather than an isolated vitamin deficiency. True hereditary metabolic disorders and serious deficiency-associated diseases are rare and in general limited to particular geographic regions and high-risk groups. Their recognition is truly important as that determines the appropriate therapeutic management. The general availability of vitamins to practically everyone and several national health programs have saved many lives and prevented complications. However, there has been some apprehension for several decades about how harmless generous dosages of these vitamins are. Overt overdosages can cause vitamin toxicity affecting various body systems including the nervous system. Systemically, vitamin toxicity is associated with nonspecific symptoms, such as nausea, vomiting, diarrhea, and skin rash which are common with any acute or chronic vitamin overdose. At a national level, recommended daily allowances for vitamins become policy statements. Nutrition policy has far reaching implications in the food industry, in agriculture, and in food provision programs. Overall, water-soluble vitamins are complex molecular structures and even today, many areas of vitamin biochemistry still need to be explored. Many readers might be of the opinion that the classic forms of nutritional deficiency diseases have faded into the background of interesting history. This has caused their diverse symptoms to be neglected by most modern physicians since vitamin enrichment of many foods automatically erases them from their consideration in differential diagnosis. Vitamin B12 and folic acid deficiencies are discussed in other chapters. PMID:24365359

Chawla, Jasvinder; Kvarnberg, David

2014-01-01

311

A relationship between vitamin B sub 12 , folic acid, ascorbic acid, and mercury uptake and methylation  

SciTech Connect

Ingestion of megadoses of certain vitamins appears to influence the in vivo methylation of mercuric chloride in guinea pigs. The addition of megadoses of vitamin B{sub 12} fed either singularly or in combination with folic acid resulted in increased methylmercury concentrations in the liver. Moreover, percent methylmercury levels were significantly increased with B{sub 12} treatment in the liver (B{sub 12} only and B{sub 12}/folic acid) and brain (B{sub 12}/vitamin C). Incorporation of high levels of folic acid into the dietary regime also increased the methylmercury concentration particularly in the liver and hair tissues. The addition of vitamin C in the diet, particularly in combination with B{sub 12} (brain) or folic acid (muscle) resulted in increased methylmercury levels in these tissues and percent methylmercury values with B{sub 12} in the muscle and brain tissue.

Zorn, N.E.; Smith, J.T. (Univ. of Tennessee, Knoxville (USA))

1990-01-01

312

Relationship of membrane-bound sulfhydryl groups to vitamin D-stimulated uptake of ( sup 75 Se)Selenite by the brush border membrane vesicles from chick duodenum  

SciTech Connect

The uptake of selenite by purified brush border membrane vesicles isolated from duodena of rachitic or vitamin D-treated chicks was studied by using radioactive selenite and a rapid filtration technique. Cholecalciferol treatment (500 IU at 72 h) significantly enhanced selenite uptake, a response that decreased when the vesicles were stored at room temperature for 2.5 h prior to the uptake measurement. Preincubation of the vesicles in 1.0 mmol/L H2O2 reduced (75Se)selenite uptake, indicating the involvement of oxidizable groups in the uptake reaction. Iodoacetic acid (IAA), a sulfhydryl-blocking reagent, at 1-2 mmol/L concentration eliminated the difference in selenite uptake due to cholecalciferol and had no effect on vesicles from rachitic animals. A higher concentration of IAA (10 mmol/L) enhanced selenite uptake manyfold and increased the absolute difference due to cholecalciferol treatment. Single intravenous doses of 100 IU cholecalciferol, 100 IU ergocalciferol, or 0.1 micrograms 1,25-dihydroxycholecalciferol also stimulated selenite uptake, suggesting a general response to vitamin D compounds. Normal animals given a single dose of 1,25-dihydroxycholecalciferol 12 h prior to killing also responded. Treatments that enhanced the uptake of (75Se)selenite also increased the amount of membrane-bound sulfhydryl groups, suggesting the involvement of membrane-bound sulfhydryl groups in the vitamin D response. A significant increase in selenite uptake by intravenous 1,25-dihydroxycholecalciferol occurred within 10 min. This rapid effect provides a new tool to probe early biochemical effects of vitamin D on intestinal epithelium.

Mykkanen, H.M.; Wasserman, R.H. (Cornell Univ., Ithaca, NY (USA))

1990-08-01

313

RBP4 Disrupts Vitamin A Uptake Homeostasis in a STRA6-Deficient Animal Model for Matthew-Wood Syndrome  

PubMed Central

SUMMARY The cellular uptake of vitamin A from its RBP4-bound circulating form (holo-RBP4) is a homeostatic process that evidently depends on the multidomain membrane protein STRA6. In humans, mutations in STRA6 are associated with Matthew-Wood syndrome, manifested by multisystem developmental malformations. Here we addressed the metabolic basis of this inherited disease. STRA6-dependent transfer of retinol from RBP4 into cultured NIH 3T3 fibroblasts was enhanced by lecithin:retinol acyltransferase (LRAT). The retinol transfer was bidirectional, strongly suggesting that STRA6 acts as a retinol channel/transporter. Loss-of-function analysis in zebrafish embryos revealed that Stra6 deficiency caused vitamin A deprivation of the developing eyes. We provide evidence that, in the absence of Stra6, holo-Rbp4 provokes nonspecific vitamin A excess in several embryonic tissues, impairing retinoic acid receptor signaling and gene regulation. These fatal consequences of Stra6 deficiency, including craniofacial and cardiac defects and microphthalmia, were largely alleviated by reducing embryonic Rbp4 levels by morpholino oligonucleotide or pharmacological treatments. PMID:18316031

Isken, Andrea; Golczak, Marcin; Oberhauser, Vitus; Hunzelmann, Silke; Driever, Wolfgang; Imanishi, Yoshikazu; Palczewski, Krzysztof; von Lintig, Johannes

2008-01-01

314

Folate and B12 in prostate cancer.  

PubMed

Mechanisms postulated to link folate and B12 metabolism with cancer, including genome-wide hypomethylation, gene-specific promoter hypermethylation, and DNA uracil misincorporation, have been observed in prostate tumor cells. However, epidemiological studies of prostate cancer risk, based on dietary intakes and blood levels of folate and vitamin B12 and on folate-pathway gene variants, have generated contradictory findings. In a meta-analysis, circulating concentrations of B12 (seven studies, OR = 1.10; 95% CI 1.01, 1.19; P = 0.002) and (in cohort studies) folate (five studies, OR = 1.18; 95% CI 1.00, 1.40; P = 0.02) were positively associated with an increased risk of prostate cancer. Homocysteine was not associated with risk of prostate cancer (four studies, OR = 0.91; 95% CI 0.69, 1.19; P = 0.5). In a meta-analysis of folate-pathway polymorphisms, MTR 2756A > G (eight studies, OR = 1.06; 95% CI 1.00, 1.12; P = 0.06) and SHMT1 1420C > T (two studies, OR = 1.11; 95% CI 1.00, 1.22; P = 0.05) were positively associated with prostate cancer risk. There were no effects due to any other polymorphisms, including MTHFR 677C > T (12 studies, OR = 1.04; 95% CI 0.97, 1.12; P = 0.3). The positive association of circulating B12 with an increased risk of prostate cancer could be explained by reverse causality. However, given current controversies over mandatory B12 fortification, further research to eliminate a causal role of B12 in prostate cancer initiation and/or progression is required. Meta-analysis does not entirely rule out a positive association of circulating folate with increased prostate cancer risk. As with B12, even a weak positive association would be a significant public health issue, given the high prevalence of prostate cancer and concerns about the potential harms versus benefits of mandatory folic acid fortification. PMID:23724740

Collin, Simon M

2013-01-01

315

Alternatives to vitamin B1 uptake revealed with discovery of riboswitches in multiple marine eukaryotic lineages.  

PubMed

Vitamin B1 (thiamine pyrophosphate, TPP) is essential to all life but scarce in ocean surface waters. In many bacteria and a few eukaryotic groups thiamine biosynthesis genes are controlled by metabolite-sensing mRNA-based gene regulators known as riboswitches. Using available genome sequences and transcriptomes generated from ecologically important marine phytoplankton, we identified 31 new eukaryotic riboswitches. These were found in alveolate, cryptophyte, haptophyte and rhizarian phytoplankton as well as taxa from two lineages previously known to have riboswitches (green algae and stramenopiles). The predicted secondary structures bear hallmarks of TPP-sensing riboswitches. Surprisingly, most of the identified riboswitches are affiliated with genes of unknown function, rather than characterized thiamine biosynthesis genes. Using qPCR and growth experiments involving two prasinophyte algae, we show that expression of these genes increases significantly under vitamin B1-deplete conditions relative to controls. Pathway analyses show that several algae harboring the uncharacterized genes lack one or more enzymes in the known TPP biosynthesis pathway. We demonstrate that one such alga, the major primary producer Emiliania huxleyi, grows on 4-amino-5-hydroxymethyl-2-methylpyrimidine (a thiamine precursor moiety) alone, although long thought dependent on exogenous sources of thiamine. Thus, overall, we have identified riboswitches in major eukaryotic lineages not known to undergo this form of gene regulation. In these phytoplankton groups, riboswitches are often affiliated with widespread thiamine-responsive genes with as yet uncertain roles in TPP pathways. Further, taxa with 'incomplete' TPP biosynthesis pathways do not necessarily require exogenous vitamin B1, making vitamin control of phytoplankton blooms more complex than the current paradigm suggests. PMID:25171333

McRose, Darcy; Guo, Jian; Monier, Adam; Sudek, Sebastian; Wilken, Susanne; Yan, Shuangchun; Mock, Thomas; Archibald, John M; Begley, Tadhg P; Reyes-Prieto, Adrian; Worden, Alexandra Z

2014-12-01

316

Low B12 levels in chronic idiopathic urticaria.  

PubMed

Recent studies suggest that autoimmune mechanisms may be involved in the etiology of chronic idiopathic urticaria (CIU). There is a higher prevalence of B12 deficiency in autoimmune diseases and possibly in gastric Helicobacter pylori (H. pylori) infection. The frequency of B12 deficiency in CIU is unknown. Our objective in this study was to determine the prevalence of B12 deficiency in patients with CIU and also its relationship to gastric H. pylori infection and serologic markers of autoimmunity in these groups. Thirty-three patients with CIU and 27 healthy controls were included in the study. Serum vitamin B12 levels, H. pylori infection and serological markers of autoimmunity (anti-thyroglobulin, thyroid microsomal, gastric parietal cell and antinuclear autoantibodies) were investigated. H. pylori infection was determined according to serology and gastric biopsy in 19 patients, serology and urea breath test in 4 patients and serology alone in the remaining 10 patients. Serum B12 levels were below the normal reference range in 11/33 (33.3%) patients with CIU. The mean serum B12 levels among patients with CIU and the controls were 281+/-127.5 pg/ml and 465.1+/-140.3 pg/ml (p=0.0001), respectively. Anti-thyroid antibodies were positive in 6 of 11 patients (54.5%) with low B12 levels, but only in 4 of 27 (14.8%) healthy controls (p=0.019). Anti-GPC antibodies were positive in 4 of 11 (36.4%) patients with CIU and low B12 levels, but only in 2 of 27 (7.4%) healthy controls (p=0.047). In CIU patients, there was no difference in the frequency of IgG H. pylori antibodies between those with low B12 levels and normal B12 levels. Among the 19 patients who had been performed gastric endoscopy, 15 patients (78.9%) had chronic antral gastritis, 2 patients (10.5%) had atrophic gastritis and there were normal findings in 2 patients (10.5%). In conclusion, serum B12 levels were found to be below the normal reference range in 33% of the patients with CIU. An association between low B12 levels and H. pylori could not be shown. The higher frequency of antithyroid and anti-GPC antibodies in patients with low B12 levels suggest that low B12 levels in CIU may be autoimmune in nature. PMID:15736714

Mete, N; Gulbahar, O; Aydin, A; Sin, A Z; Kokuludag, A; Sebik, F

2004-01-01

317

Uptake of technetium-99m methylene diphosphonate by fractured and osteoporotic bone after a pulse dose of Vitamin D/sub 3/. [Rats  

SciTech Connect

The effect of a pulse dose of Vitamin D/sub 3/ on uptake of (/sup 99m/Tc)MDP by fractured and osteoporotic bone, respectively, was compared with D/sub 3/'s effect on uptake by normal bone in rats. At 4, 7, and 14 days, respectively, after femoral fracture, basal uptake was significantly increased at the fracture site by 336.8, 276.1, and 183.5%, respectively, over the contralateral control site. D/sub 3/-treated rats had lower uptakes than untreated controls at all three fracture sites and at 12 of 15 normal bone sites but analysis of variance showed the uptake differences were not significant. Cortisone-induced osteoporosis caused a significant decrease in basal uptake. The decrease occurred in all nine bone areas studied. D/sub 3/ caused a significant increase in uptake by these osteoporotic bones, but a significant decrease in uptake by the same bones in normal controls. Thus, D/sub 3/ had an effect on uptake by the bone lesion, osteoporosis, that differed from D/sub 3/'s effect on uptake by fracture or normal bone.

Carr, E.A. Jr.; Carroll, M.; Montes, M.; Zielezny, M.

1985-04-01

318

Reverse Effect of Mammalian Hypocalcemic Cortisol in Fish: Cortisol Stimulates Ca2+ Uptake via Glucocorticoid Receptor-Mediated Vitamin D3 Metabolism  

PubMed Central

Cortisol was reported to downregulate body-fluid Ca2+ levels in mammals but was proposed to show hypercalcemic effects in teleostean fish. Fish, unlike terrestrial vertebrates, obtain Ca2+ from the environment mainly via the gills and skin rather than by dietary means, and have to regulate the Ca2+ uptake functions to cope with fluctuating Ca2+ levels in aquatic environments. Cortisol was previously found to regulate Ca2+ uptake in fish; however, the molecular mechanism behind this is largely unclear. Zebrafish were used as a model to explore this issue. Acclimation to low-Ca2+ fresh water stimulated Ca2+ influx and expression of epithelial calcium channel (ecac), 11?-hydroxylase and the glucocorticoid receptor (gr). Exogenous cortisol increased Ca2+ influx and the expressions of ecac and hydroxysteroid 11-beta dehydrogenase 2 (hsd11b2), but downregulated 11?-hydroxylase and the gr with no effects on other Ca2+ transporters or the mineralocorticoid receptor (mr). Morpholino knockdown of the GR, but not the MR, was found to impair zebrafish Ca2+ uptake function by inhibiting the ecac expression. To further explore the regulatory mechanism of cortisol in Ca2+ uptake, the involvement of vitamin D3 was analyzed. Cortisol stimulated expressions of vitamin D-25hydroxylase (cyp27a1), cyp27a1 like (cyp27a1l), 1?-OHase (cyp27b1) at 3 dpf through GR, the first time to demonstrate the relationship between cortisol and vitamin D3 in fish. In conclusion, cortisol stimulates ecac expression to enhance Ca2+ uptake functions, and this control pathway is suggested to be mediated by the GR. Lastly, cortisol also could mediate vitamin D3 signaling to stimulate Ca2+ uptake in zebrafish. PMID:21887296

Lin, Chia-Hao; Tsai, I-Lun; Su, Che-Hsien; Tseng, Deng-Yu; Hwang, Pung-Pung

2011-01-01

319

Stability of fat-soluble and water-soluble vitamins in artificially prepared, vitamin-enriched, lyophilized serum  

Microsoft Academic Search

Vitamin-enriched, lyophilized serum (VES) was prepared for an inter-laboratory study to compare vitamin assays. The VES contained water-soluble vitamins (vitamin B1, vitamin B12, vitamin C, and folate), fat- soluble vitamins (vitamin A and vitamin E), and cholesterol. We performed stability studies and determined vitamin concentra- tions and total cholesterol in VES stored at 201C for 12 months. Our recovery of

Hiroshi Ihara; Naotaka Hashizume; Tadashi Matsubayashi; Koichi Futaki; Masayuki Yoshida; Naotoshi Sagawa; Makoto Fujisaki; Kazuo Mita; Akira Kadota

2004-01-01

320

Hyperhomocysteinemia in chronic alcoholism: correlation with folate, vitamin Bi 2, and vitamin B6 status13  

Microsoft Academic Search

Serum homocysteine concentrations have been shown to be a sensitive functional indicator of intracellular folate, vitamin B-12, and vitamin B-6 status. Chronic alcoholism is known to interfere with one-carbon metabolism, for which the above vitamins serve as coenzymes. In the present study, these vitamins were assessed in 32 chronic alcoholics and 3 1 healthy volunteers by measuring blood vitamin concentrations

MarIlia L Cravo; Lulsa M Gloria; Jacob Seihub; Marie R Nadeau; Manuela P Resende; C Nobre Leit; F Costa Mira

321

Maternal Serum B 12 Levels and Risk for Neural Tube Defects in a Texas-Mexico Border Population  

Microsoft Academic Search

PURPOSE: Neural tube defects (NTDs) are common birth defects that can be prevented with folate fortification and supplementation. Studies suggest that other nutrients may also be essential to neural tube closure and have a potential role in risk reduction, with vitamin B12 mentioned most often. We determined the effect of maternal serum B12 levels, measured postpartum, on the risk of

Lucina Suarez; Kate Hendricks; Marilyn Felkner; Elaine Gunter

2003-01-01

322

Studies in the biosynthesis of vitamin B12  

E-print Network

The Pseudomonas denitrificans coba and the Salmonella typhimurium cbid genes were overexpressed in the heterologous E.coli system. The function of P.denitrificans coba gene product was identified as S-adenosyl methionine dependent methyl transferase...

Anousis, Nick

2012-06-07

323

How I treat cobalamin (vitamin B12) deficiency  

PubMed Central

The challenges in medical management of cobalamin deficiency lie in attention to the unique pathophysiology that underlies cobalamin deficiency, more than in the mechanics of therapy. The central physiologic principles are that clinically important deficiency is more likely to occur (and progress) when intrinsic factor–driven absorption fails than when diet is poor and that most causes take years to produce clinically obvious deficiency. Transient defects have little clinical impact. The key management principle is the importance of follow-up, which also requires knowing how the deficiency arose. The virtues of these principles are not always fully appreciated. Recent developments have made diagnosis and management more difficult by diminishing the ability to determine cobalamin absorption status. Clinicians must also grapple with premature medicalization of isolated, mild biochemical changes that added many asymptomatic cases of still undetermined medical relevance to their caseload, often expanded by inflated cobalamin level criteria. The potential for misattribution of cobalamin-unrelated presentations to nongermane cobalamin and metabolite abnormalities has grown. Pathophysiologically based management requires systematic attention to each of its individual components: correctly diagnosing cobalamin deficiency, reversing it, defining its underlying cause, preventing relapse, managing the underlying disorder and its complications, and educating the patient. PMID:18606874

2008-01-01

324

An Endocytic Pathway Essential for Renal Uptake and Activation of the Steroid 25-(OH) Vitamin D 3  

Microsoft Academic Search

Steroid hormones may enter cells by diffusion through the plasma membrane. However, we demonstrate here that some steroid hormones are taken up by receptor-mediated endocytosis of steroid-carrier complexes. We show that 25-(OH) vitamin D3 in complex with its plasma carrier, the vitamin D–binding protein, is filtered through the glomerulus and reabsorbed in the proximal tubules by the endocytic receptor megalin.

Anders Nykjaer; Duska Dragun; Diego Walther; Henrik Vorum; Christian Jacobsen; Joachim Herz; Flemming Melsen; Erik Ilsoe Christensen; Thomas E Willnow

1999-01-01

325

[Vitamin status in diabetic neuropathy (thiamine, riboflavin, pyridoxin, cobalamin and tocopherol)].  

PubMed

Investigations on the vitamin pattern of diabetic neuropathy: thiamine, riboflavin, pyridoxine, cobalamin and tocopherol. The contents of the vitamins mentioned above have been measured in the blood of 119 patients (53 diabetic neuropathies, 66 diabetics without neuropathy). The incidence of neuropathy shows a strong correlation with the duration of the diabetic state, but not with sex, nor with concomitant diseases such as adipositas, hypertension, heart and circulatory diseases, except retinopathia diabetica. Most of the diabetics in our study are well supplied with vitamins B1, B2, and E; B6 and B12 are occasionally low, but there is no statistically relevant difference between diabetic controls and neuropathies. Adipose patients have neither a markedly different vitamin content nor a different calory uptake from non-adipose patients. A general trend towards reduced total calory uptake is seen in old age, men (lower protein intake) and women (lower carbohydrate intake) obviously differing somewhat in their habits. The influence of therapy on the vitamin pattern is not clear cut, except for patients under diet and biguanide-therapy showing a higher proportion of low or subnormal B12 values. The increased frequency of neuropathies in patients treated with sulfonyl-urea approaches only the limits of significance and needs further investigations. PMID:7053098

Rieder, H P; Berger, W; Fridrich, R

1980-03-01

326

The vitamin D receptor (VDR) is expressed in skeletal muscle of male mice and modulates 25-hydroxyvitamin D (25OHD) uptake in myofibers.  

PubMed

Vitamin D deficiency is associated with a range of muscle disorders, including myalgia, muscle weakness, and falls. In humans, polymorphisms of the vitamin D receptor (VDR) gene are associated with variations in muscle strength, and in mice, genetic ablation of VDR results in muscle fiber atrophy and motor deficits. However, mechanisms by which VDR regulates muscle function and morphology remain unclear. A crucial question is whether VDR is expressed in skeletal muscle and directly alters muscle physiology. Using PCR, Western blotting, and immunohistochemistry (VDR-D6 antibody), we detected VDR in murine quadriceps muscle. Detection by Western blotting was dependent on the use of hyperosmolar lysis buffer. Levels of VDR in muscle were low compared with duodenum and dropped progressively with age. Two in vitro models, C2C12 and primary myotubes, displayed dose- and time-dependent increases in expression of both VDR and its target gene CYP24A1 after 1,25(OH)2D (1,25 dihydroxyvitamin D) treatment. Primary myotubes also expressed functional CYP27B1 as demonstrated by luciferase reporter studies, supporting an autoregulatory vitamin D-endocrine system in muscle. Myofibers isolated from mice retained tritiated 25-hydroxyvitamin D3, and this increased after 3 hours of pretreatment with 1,25(OH)2D (0.1 nM). No such response was seen in myofibers from VDR knockout mice. In summary, VDR is expressed in skeletal muscle, and vitamin D regulates gene expression and modulates ligand-dependent uptake of 25-hydroxyvitamin D3 in primary myofibers. PMID:24949660

Girgis, Christian M; Mokbel, Nancy; Cha, Kuan Minn; Houweling, Peter J; Abboud, Myriam; Fraser, David R; Mason, Rebecca S; Clifton-Bligh, Roderick J; Gunton, Jenny E

2014-09-01

327

The Vitamin D Receptor (VDR) Is Expressed in Skeletal Muscle of Male Mice and Modulates 25-Hydroxyvitamin D (25OHD) Uptake in Myofibers  

PubMed Central

Vitamin D deficiency is associated with a range of muscle disorders, including myalgia, muscle weakness, and falls. In humans, polymorphisms of the vitamin D receptor (VDR) gene are associated with variations in muscle strength, and in mice, genetic ablation of VDR results in muscle fiber atrophy and motor deficits. However, mechanisms by which VDR regulates muscle function and morphology remain unclear. A crucial question is whether VDR is expressed in skeletal muscle and directly alters muscle physiology. Using PCR, Western blotting, and immunohistochemistry (VDR-D6 antibody), we detected VDR in murine quadriceps muscle. Detection by Western blotting was dependent on the use of hyperosmolar lysis buffer. Levels of VDR in muscle were low compared with duodenum and dropped progressively with age. Two in vitro models, C2C12 and primary myotubes, displayed dose- and time-dependent increases in expression of both VDR and its target gene CYP24A1 after 1,25(OH)2D (1,25 dihydroxyvitamin D) treatment. Primary myotubes also expressed functional CYP27B1 as demonstrated by luciferase reporter studies, supporting an autoregulatory vitamin D-endocrine system in muscle. Myofibers isolated from mice retained tritiated 25-hydroxyvitamin D3, and this increased after 3 hours of pretreatment with 1,25(OH)2D (0.1nM). No such response was seen in myofibers from VDR knockout mice. In summary, VDR is expressed in skeletal muscle, and vitamin D regulates gene expression and modulates ligand-dependent uptake of 25-hydroxyvitamin D3 in primary myofibers. PMID:24949660

Mokbel, Nancy; Cha, Kuan Minn; Houweling, Peter J.; Abboud, Myriam; Fraser, David R.; Mason, Rebecca S.; Clifton-Bligh, Roderick J.

2014-01-01

328

Vitamin B??-containing plant food sources for vegetarians.  

PubMed

The usual dietary sources of Vitamin B12 are animal-derived foods, although a few plant-based foods contain substantial amounts of Vitamin B12. To prevent Vitamin B12 deficiency in high-risk populations such as vegetarians, it is necessary to identify plant-derived foods that contain high levels of Vitamin B12. A survey of naturally occurring plant-derived food sources with high Vitamin B12 contents suggested that dried purple laver (nori) is the most suitable Vitamin B12 source presently available for vegetarians. Furthermore, dried purple laver also contains high levels of other nutrients that are lacking in vegetarian diets, such as iron and n-3 polyunsaturated fatty acids. Dried purple laver is a natural plant product and it is suitable for most people in various vegetarian groups. PMID:24803097

Watanabe, Fumio; Yabuta, Yukinori; Bito, Tomohiro; Teng, Fei

2014-05-01

329

Mammalian colonocytes possess a carrier-mediated mechanism for uptake of vitamin B3 (niacin): studies utilizing human and mouse colonic preparations.  

PubMed

Niacin (vitamin B3; nicotinic acid) plays an important role in maintaining redox state of cells and is obtained from endogenous and exogenous sources. The latter source has generally been assumed to be the dietary niacin, but another exogenous source that has been ignored is the niacin that is produced by the normal microflora of the large intestine. For this source of niacin to be bioavailable, it needs to be absorbed, but little is known about the ability of the large intestine to absorb niacin and the mechanism involved. Here we addressed these issues using the nontransformed human colonic epithelial NCM460 cells, native human colonic apical membrane vesicles (AMV) isolated from organ donors, and mouse colonic loops in vivo as models. Uptake of ³H-nicotinic acid by NCM460 cells was: 1) acidic pH (but not Na?) dependent; 2) saturable (apparent Km = 2.5 ± 0.8 ?M); 3) inhibited by unlabeled nicotinic acid, nicotinamide, and probenecid; 4) neither affected by other bacterially produced monocarboxylates, monocarboxylate transport inhibitor, or by substrates of the human organic anion transporter-10; 5) affected by modulators of the intracellular protein tyrosine kinase- and Ca²?-calmodulin-regulatory pathways; and 6) adaptively regulated by extracellular nicotinate level. Uptake of nicotinic acid by human colonic AMV in vitro and by mouse colonic loops in vivo was also carrier mediated. These findings report, for the first time, that mammalian colonocytes possess a high-affinity carrier-mediated mechanism for nicotinate uptake and show that the process is affected by intracellular and extracellular factors. PMID:23744738

Kumar, Jeyan S; Subramanian, Veedamali S; Kapadia, Rubina; Kashyap, Moti L; Said, Hamid M

2013-08-01

330

B12Hn and B12Fn: planar vs icosahedral structures  

PubMed Central

Using density functional theory and quantum Monte Carlo calculations, we show that B12Hn and B12Fn (n = 0 to 4) quasi-planar structures are energetically more favorable than the corresponding icosahedral clusters. Moreover, we show that the fully planar B12F6 cluster is more stable than the three-dimensional counterpart. These results open up the possibility of designing larger boron-based nanostructures starting from quasi-planar or fully planar building blocks. PMID:22546348

2012-01-01

331

Subacute combined degeneration of the spinal cord in cblC disorder despite treatment with B12  

Microsoft Academic Search

Subacute combined degeneration (SCD) of the spinal cord is a characteristic complication of vitamin B12 deficiency, but it has never been neuropathologically demonstrated in a B12-inborn error of metabolism. In this report SCD is documented in a 15-year-old boy with early-onset cobalamin C (cblC) disorder. The neuropathologic findings included multifocal demyelination and vacuolation with predilection for the dorsal and lateral

Sharon E. Smith; Hannah C. Kinney; Kathryn J. Swoboda; Harvey L. Levy

2006-01-01

332

Ultrastructure of the H. pylori microbe in individuals having macrocytosis and B12 deficiency.  

PubMed

The incidence of Helicobacter pylori gastritis is high in India and the number of individuals with vitamin B12 deficiency is also large. An association has been found between these two factors. It is necessary to determine whether H. pylori infection may be a factor in the causation of B12 deficiency and whether it is associated with any morphological changes on ultrastructural examination. A cohort-based study has been performed, which includes 505 young asymptomatic males. These cases have been investigated for presence of H. pylori and macrocytosis. The study confirms an association between H. pylori infection and B12 deficiency. It is recommended that H. pylori infection be looked for in subjects having macrocytosis of unknown etiology. PMID:21867407

Khubchandani, Shaila R; Kulkarni, Satish; Teckchandani, Suresh; Chitale, Arun

2011-10-01

333

Vitamin B 12 and vitamin B 6 supplementation is needed among adults with phenylketonuria (PKU)  

Microsoft Academic Search

Summary  Phenylketonuria (PKU) is caused by an autosomal recessive deficiency of the enzyme phelnylalanine hydroxylase leading to a\\u000a failure to convert phenylalanine to tyrosine. To avoid irreversible neurological damage because of increased phenylalanine,\\u000a treatment is instituted rapidly after birth. We examined 31 adult PKU patients living on a less protein-restricted diet. Theoretically,\\u000a these PKU patients had an increased risk of developing

A. M. Hvas; E. Nexo; J. B. Nielsen

2006-01-01

334

Vitamin A  

MedlinePLUS

... most common type of pro-vitamin A is beta-carotene. Vitamin A is also available in dietary supplements, ... retinyl acetate or retinyl palmitate (preformed vitamin A), beta-carotene (pro-vitamin A) or a combination of preformed ...

335

Vitamin E  

MedlinePLUS

... QuickFacts Datos en español Health Professional Other Resources Vitamin E Fact Sheet for Consumers What is vitamin E and what does it do? Vitamin E ... out more about vitamin E? Disclaimer How much vitamin E do I need? The amount of vitamin ...

336

?-Carotene supplementation decreases placental transcription of LDL receptor-related protein 1 in wild-type mice and stimulates placental ?-carotene uptake in marginally vitamin A-deficient mice.  

PubMed

The human diet contains ?-carotene as the most abundant precursor of vitamin A, an essential nutrient for embryogenesis. Our laboratory previously showed the importance of ?-carotene metabolism via ?-carotene-15,15'-oxygenase (CMOI) to support mouse embryonic development. However, the mechanisms regulating embryonic acquisition and utilization of ?-carotene from the maternal circulation via placenta remain unknown. We used wild-type (WT) and Lrat(-/-)Rbp(-/-) (L(-/-)R(-/-)) mice, the latter being a model of marginal vitamin A deficiency. Pregnant dams, fed a nonpurified diet sufficient in vitamin A throughout life, were i.p. supplemented with ?-carotene or vehicle at 13.5 d postcoitum (dpc). Effects of this acute maternal supplementation on retinoid and ?-carotene metabolism in maternal (serum, liver) and developing tissues (placenta, yolk sac, embryo) were investigated at 14.5 dpc. We showed that, upon supplementation, placental ?-carotene concentrations were greater in L(-/-)R(-/-) than in WT mice. However, the retinoid (retinol and retinyl ester) concentrations remained unchanged in placenta (and in all other tissues analyzed) of both genotypes upon ?-carotene administration. We also showed that upon a single i.p. ?-carotene supplementation, placental LDL receptor-related protein (Lrp1) mRNA expression was lower in WT mice, and embryonic CmoI mRNA expression was greater in L(-/-)R(-/-) mice. Together, these data suggest a potential role of LRP1 in mediating the uptake of ?-carotene across the placenta and that even a marginally impaired maternal vitamin A status may influence uptake and utilization of ?-carotene by the placenta and the embryo. PMID:22739378

Wassef, Lesley; Shete, Varsha; Hong, Alice; Spiegler, Elizabeth; Quadro, Loredana

2012-08-01

337

Dietary Supplements and Health Aids: A Critical Evaluation, Part 1- Vitamins and Minerals.  

ERIC Educational Resources Information Center

Evaluates vitamins/minerals, distinguishing whether studies cited used animal or human subjects. Vitamins discussed include niacin and vitamins B-12, C, A, D, E, and megavitamin supplementation (intake of vitamins at levels 10 times the recommended daily allowance). Minerals considered include dolomite/bone meal, chromium (glucose tolerance…

Dubick, Michael A.; Rucker, Robert B.

1983-01-01

338

Ferrocene analogues of sandwich B12·Cr·B12: a theoretical study.  

PubMed

The bowl B(12) cluster was previously reported to be analogous to benzene and predicted to be one of the best candidates to be new inorganic ligands. The structural stability and electronic properties of a new sandwich compound Cr(B(12))(2) (D(3d)) have been investigated by using density functional theory. It is found that the sandwich Cr(B(12))(2) (D(3d)) is a stable complex with large binding energy (-5.93 eV) and HOMO-LUMO gap (2.37 eV), as well as Fe(C(5)H(5))(2) and Cr(C(6)H(6))(2), following the 18-electron principle. The detailed molecular orbitals and aromaticity analyses indicate that the sandwich compound Cr(B(12))(2) (D(3d)) is electronically very stable. The natural bond orbital analysis suggests that spd-? interaction plays an important role in the sandwich compounds. PMID:23320677

Yuan, Yuan; Cheng, Longjiu

2013-01-14

339

Photoelectron spectroscopy of aromatic compound clusters of the B12 all-boron benzene: B12Au- and B12(BO)-.  

PubMed

We report a photoelectron spectroscopy and density-functional theory study of the B12Au(-) and B13O(-) clusters and their neutrals, which are shown to be six ? electron aromatic compounds between the quasi-planar all-boron B12 benzene-analogue and a monovalent Au or BO ligand. Electron affinities of B12Au and B13O are measured to be 3.48 ± 0.04 and 3.90 ± 0.04 eV, respectively. Structural searches are performed for B12Au(-) and B13O(-), which are compared with the isovalent B12H(-) cluster. The global minima of B12Au(-) and B13O(-) both feature an almost intact B12 cluster with the Au and BO ligands bonded to its periphery, respectively. For B12Au(-), a low-lying isomer is also identified, which is only 0.4 kcal mol(-1) above the global minimum, in agreement with the experimental observation of a weakly populated isomer in the cluster beam of B12Au(-). These aromatic compound clusters provide new examples for the Au/H isolobal analogy and the boronyl (BO) chemistry. PMID:23666408

Bai, Hui; Zhai, Hua-Jin; Li, Si-Dian; Wang, Lai-Sheng

2013-06-28

340

Organometallic B12 -DNA Conjugate: Synthesis, Structure Analysis, and Studies of Binding to Human B12 -Transporter Proteins.  

PubMed

Design, synthesis, and structural characterization of a B12 -octadecanucleotide are presented herein, a new organometallic B12 -DNA conjugate. In such covalent conjugates, the natural B12 moiety may be a versatile vector for controlled in vivo delivery of oligonucleotides to cellular targets in humans and animals, through the endogenous B12 transport systems. Binding of the organometallic B12 octadecanucleotide to the three important human proteins of B12 transport was studied, to examine its structural suitability for the task of eventual in vivo oligonucleotide delivery. Binding was efficient with transcobalamin (TC), but not so efficient with the homologous glycoproteins intrinsic factor and haptocorrin. Binding of the B12 octadecanucleotide to TC suggests the capacity of the B12 moiety to serve as a natural vector for specific transport of single stranded, organometallic oligonucleotide loads from the blood stream into cells. PMID:25168390

Hunger, Miriam; Mutti, Elena; Rieder, Alexander; Enders, Barbara; Nexo, Ebba; Kräutler, Bernhard

2014-10-01

341

Effects of B vitamin injections on plasma B vitamin concentrations of feed-restricted beef calves infected with bovine herpesvirus-1.  

PubMed

For nonruminants, stress and disease greatly increase requirements for vitamin B6, folic acid, pantothenic acid, and ascorbate. The effects of feed restriction, virus infection, and vitamin injections on plasma concentrations of B vitamins critical to the immune response were evaluated. Twelve beef steer calves, 6 to 8 mo of age, were fed below maintenance for 17 d and deprived of food for 3 d during a 20-d period after weaning. They then were inoculated intranasally with live attenuated bovine herpesvirus-1 (BHV-1). Six calves received saline injections and six received injections of a B vitamin mixture and ascorbate every 48 h for 14 d before and 14 d after inoculation. A mild respiratory infection developed in all calves 4 to 5 d after inoculation. In control calves, restricted intake and food deprivation decreased plasma vitamin B6 and pantothenate and increased vitamin B12 but did not affect folic acid and ascorbate concentrations. Vitamin injections increased plasma concentrations of vitamin B6, folic acid, vitamin B12, pantothenic acid, and ascorbate (P < .002). Plasma concentrations of vitamin B6, vitamin B12, pantothenic acid, and ascorbate, but not folic acid, were markedly reduced in all calves during the BHV-1 infection (P = .001). The vitamin B6, pantothenic acid, vitamin B12, and ascorbate status of stressed calves may affect their immune response to vaccination or infection. PMID:8791209

Dubeski, P L; Owens, F N; Song, W O; Coburn, S P; Mahuren, J D

1996-06-01

342

Vitamin D  

MedlinePLUS

... Manage a Serious Allergic Reaction Quiz: Baseball Injuries Vitamin D KidsHealth > Teens > Food & Fitness > Nutrition Basics > Vitamin ... get the recommended daily amount. Continue How Much Vitamin D Do I Need? The Institute of Medicine ( ...

343

Congenital B12 deficiency following maternal gastric bypass.  

PubMed

Here we present a case of severe B12 deficiency in an exclusively breastfed infant, born to a mother who had undergone gastric bypass 6 years earlier. At 4 months of age, the infant presented with pancytopenia and developmental delay. Our evaluation revealed physical and neurological developmental delay, pancytopenia with macrocytosis, with head imaging showing cortical and subcortical atrophy. Serum studies showed low B12, normal folate and iron. Treatment with parenteral B12 led to the resolution of the pancytopenia, steady weight gain and improved neurological status. The child is currently 16 months old with normal anthropometric and hematological parameters and normal B12 levels on a regular diet. Gross motor and speech developments are significantly delayed. This case illustrates that maternal B12 deficiency following gastric bypass surgery may lead to severe B12 deficiency with long-term neurological sequelae in their infants. Screening and prompt treatment of these deficiencies both during pregnancy and during infancy are important. PMID:19710657

Celiker, M Y; Chawla, A

2009-09-01

344

Isotope dependencies of Raman spectra of B12As2, B12P2, B12O2, and B12+xC3-x: Bonding of intericosahedral chains  

NASA Astrophysics Data System (ADS)

The structures of B12As2, B12P2, B12O2, and B12+xC3-x (0.15B12 or B11C icosahedra and As-As, P-P, O-O, or (C1-yBy)-B-(C1-zBz) intericosahedral chains. The relative stiffnesses of the chain atoms' intrachain and extrachain bonding are probed with Raman spectroscopy by measuring the boron-isotope dependence of the chains' symmetric stretching frequencies. The dependencies of chains' symmetric stretching frequencies on boron mass measures the degree to which icosahedral boron atoms are carried along in the chain atoms' motions. The absence of a measurable boron involvement in these modes for B12As2 and B12P2 indicates that the bonding between the two atoms of their chains is much stiffer than these atoms' bonding to icosahedral boron atoms. By contrast, substantial boron involvement in the symmetric-stretch mode of B12O2 indicates much softer bonding of the chain oxygen atoms to one another than to icosahedral boron atoms. The strong boron participation in the boron carbide Raman mode assigned to the symmetric stretch of CBC chains suggests relatively soft bonding between the chain's atoms. The declining intensity of this CBC-chain-stretching mode as x increases from 0.15 toward 1.0 in B12+xC3-x is consistent with the carbon atoms being removed primarily from chains rather than from icosahedra. Other features of our Raman spectra provide complementary evidence that carbon atoms are preferentially retained in boron carbides' icosahedra rather than in its chains. In particular, strong carbon participation in Raman modes associated with vibrations of icosahedral atoms is observed at all carbon concentrations, 0.15

Aselage, T. L.; Tallant, D. R.; Emin, D.

1997-08-01

345

Vitamin C  

MedlinePLUS

... mg zinc, 400 IU vitamin E, 15 mg beta-carotene , and 2 mg copper for about 6 years ... other antioxidants (such as vitamin E, selenium, and beta-carotene) reduced the heart-protective effects of two drugs ...

346

Vitamin A  

MedlinePLUS

... provitamin A in foods and dietary supplements is beta-carotene . Table of Contents What is vitamin A and ... retinyl acetate or retinyl palmitate (preformed vitamin A), beta-carotene (provitamin A), or a combination of preformed and ...

347

Vitamin K  

MedlinePLUS

... IL: American Dietetic Association; 2007. Institute of Medicine, Food and Nutrition Board. Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, ...

348

Vitamin E  

MedlinePLUS

... of most nutrients. Should you take vitamin or mineral supplements during cancer treatment? Many researchers and clinicians ... advise their patients to avoid antioxidant vitamin and mineral supplements during treatment, but some surveys suggest this ...

349

Vitamin C  

MedlinePLUS

Vitamin C is an antioxidant. It is important for your skin, bones, and connective tissue. It promotes healing and helps the body absorb iron. Vitamin C comes from fruits and vegetables. Good sources ...

350

Vitamin D  

MedlinePLUS

Cholecalciferol; Vitamin D3; Ergocalciferol; Vitamin D2 ... two different forms: D 2 (ergocalciferol) D 3 (cholecalciferol) ... breast-feeding teens and women One microgram of cholecalciferol (D 3 ) is the same as 40 IU ...

351

Vitamin Analysis  

NASA Astrophysics Data System (ADS)

Vitamins are defined as relatively low-molecular-weight compounds which humans, and for that matter, any living organism that depends on organic matter as a source of nutrients, require small quantities for normal metabolism. With few exceptions, humans cannot synthesize most vitamins and therefore need to obtain them from food and supplements. Insufficient levels of vitamins result in deficiency diseases [e.g., scurvy and pellagra, which are due to the lack of ascorbic acid (vitamin C) and niacin, respectively].

Pegg, Ronald B.; Landen, W. O.; Eitenmiller, Ronald R.

352

Sodium superionic conduction in Na2B12H12.  

PubMed

Impedance measurements indicate that Na2B12H12 exhibits dramatic Na(+) conductivity (on the order of 0.1 S cm(-1)) above its order-disorder phase-transition at ?529 K, rivaling that of current, solid-state, ceramic-based, Na-battery electrolytes. Superionicity may be aided by the large size, quasispherical shape, and high rotational mobility of the B12H12(2-) anions. PMID:24584582

Udovic, Terrence J; Matsuo, Motoaki; Unemoto, Atsushi; Verdal, Nina; Stavila, Vitalie; Skripov, Alexander V; Rush, John J; Takamura, Hitoshi; Orimo, Shin-ichi

2014-04-11

353

Vitamin A  

MedlinePLUS

Vitamin A plays a role in your Vision Bone growth Reproduction Cell functions Immune system Vitamin A is an antioxidant. It can come from ... vegetables. Animal sources include liver and whole milk. Vitamin A is also added to foods like cereals. ...

354

Vitamin D  

MedlinePLUS

Vitamin D helps your body absorb calcium. Calcium is one of the main building blocks of bone. A lack of vitamin D can lead to bone diseases such as osteoporosis or rickets. Vitamin D also has a role in your nerve, ...

355

Vitamin D  

MedlinePLUS

... labels. Can I get vitamin D from the sun? The body makes vitamin D when skin is directly exposed to the sun, and most people meet at least some of ... skin makes. However, despite the importance of the sun to vitamin D synthesis, it is prudent to ...

356

Vitamin D  

PubMed Central

Vitamin D has received a lot of attention recently as a result of a meteoric rise in the number of publications showing that vitamin D plays a crucial role in a plethora of physiological functions and associating vitamin D deficiency with many acute and chronic illnesses including disorders of calcium metabolism, autoimmune diseases, some cancers, type 2 diabetes mellitus, infectious diseases and cardiovascular disease. The recent data on vitamin D from experimental, ecological, case-control, retrospective and prospective observational studies, as well as smaller intervention studies, are significant and confirm the sunshine vitamin’s essential role in a variety of physiological and preventative functions. The results of these studies justify the recommendation to improve the general vitamin D status in children and adults by means of a healthy approach to sunlight exposure, consumption of foods containing vitamin D and supplementation with vitamin D preparations. In general, closer attention should therefore be paid to vitamin D deficiency in medical and pharmaceutical practice than has been the case hitherto. PMID:24516687

Grober, Uwe; Spitz, Jorg; Reichrath, Jorg; Kisters, Klaus; Holick, Michael F

2013-01-01

357

TD-DFT insight into photodissociation of the Co-C bond in coenzyme B12.  

PubMed

Coenzyme B12 (AdoCbl) is one of the most biologically active forms of vitamin B12, and continues to be a topic of active research interest. The mechanism of Co-C bond cleavage in AdoCbl, and the corresponding enzymatic reactions are however, not well understood at the molecular level. In this work, time-dependent density functional theory (TD-DFT) has been applied to investigate the photodissociation of coenzyme B12. To reduce computational cost, while retaining the major spectroscopic features of AdoCbl, a truncated model based on ribosylcobalamin (RibCbl) was used to simulate Co-C photodissociation. Equilibrium geometries of RibCbl were obtained by optimization at the DFT/BP86/TZVP level of theory, and low-lying excited states were calculated by TD-DFT using the same functional and basis set. The calculated singlet states, and absorption spectra were simulated in both the gas phase, and water, using the polarizable continuum model (PCM). Both spectra were in reasonable agreement with experimental data, and potential energy curves based on vertical excitations were plotted to explore the nature of Co-C bond dissociation. It was found that a repulsive (3)(?Co-C ? ?(*) Co-C) triplet state became dissociative at large Co-C bond distance, similar to a previous observation for methylcobalamin (MeCbl). Furthermore, potential energy surfaces (PESs) obtained as a function of both Co-CRib and Co-NIm distances, identify the S1 state as a key intermediate generated during photoexcitation of RibCbl, attributed to a mixture of a metal-to-ligand charge transfer (MLCT) and a ? bonding-ligand charge transfer (SBLCT) states. PMID:24790969

Liu, Hui; Kornobis, Karina; Lodowski, Piotr; Jaworska, Maria; Kozlowski, Pawel M

2013-01-01

358

Organo-modified layered double hydroxide-catalyzed Fenton-like ultra-weak chemiluminescence for specific sensing of vitamin B?? in egg yolks.  

PubMed

In general, the chemiluminescence (CL) sensing of vitamin B12 is achieved by determining Co(II) liberated from acidified vitamin B12 by a luminol system. However, the luminol system for sensing vitamin B12 has poor selectivity due to serious interference from other metal ions. In this study, as a novel CL amplifier of the Co(II)+H2O2+OH(-) ultra-weak CL reaction (Fenton-like system), dodecylbenzene sulfonate (DBS)-layered double hydroxides (LDHs) have been applied to the specific determination of vitamin B12 by liberating Co(II). The CL intensity increased with increasing the concentration of vitamin B12 in a wide range from 1.0 ng mL(-1) to 5 ?g mL(-1) with a detection limit of 0.57 ng mL(-1) (S/N=3). The proposed method has been successfully applied to determine vitamin B12 in egg yolk with simple procedures, shorter time and higher selectivity. Recoveries from spiked real samples were 96-103%. The results of the proposed method for sensing vitamin B12 in real samples were agreed with those obtained by the standard inductively coupled plasma mass spectrometry (ICP-MS) method. To the best of our knowledge, this is the first report on the CL sensing of vitamin B12 with high selectivity in the absence of luminol. PMID:25127574

Zhang, Lijuan; Rong, Wanqi; Lu, Chao; Zhao, Lixia

2014-11-01

359

The importance of vitamin B12 and unidentified factors in the nutrition of the domestic fowl  

E-print Network

extract is required when administered orally than when injected intramuscularly (Minot and 16 ? ? *Castle *31; Isaacs, et al* f33; Gansslen, et al. T30)? Some patients fail to respond to oral liver extract therapy, although they show a positive... hematopoietic response after injection of liver extract or after the feeding of dessicated stomach (Renshaw, *30; Leschke, T30; Snapper and Du Preez, ? 31; Sturgis and Isaacs, *31). Castle and Locke ( ?28) reported that the administration of liver or liver...

Olcese, Orlando

2013-10-04

360

Observations on the vitamin B12 binding substance of egg yolk  

E-print Network

:vip'epos is "I -'. 6". ~aetio . 'h""i, . '-o':'". 4h+?'-'0 a L'iel. 'J"'i e i '~~ Lote6'*, :"} ' '!s, :''?:;"3~!" 7ttx~f5 a' !. :g& 4''t '!. ~", '~ 'sl&';sCQ&:. ":::3 X j i::"z'f, " ": "?h' Cic' Q, l' ri a tetal vol&m of 3 1&em. coopt+? th@ tilbes vot8...' 6 ' 9tii. "iiM i&y ?~XN3Xlii; Svi-'94K'. 4:. 8 p~ Ql'P P'91! !:. r, . ' '-'. %~ 9'&X'A'L, +c f86404' 3~!Ci5 ~hg ~Q*~" 5 + &lGi'i"t: . 1&biY8 "4&C 'W)i~ ". Qg l8QX' '&8 5tyGLl34 KO . "9Qti'. ". XQ w4 P' , Ci & ZQZ' ", . '?j8X": CK' &W 'ki...

Ener, Huseyin Siret

2012-06-07

361

Cobalamin (Vitamin B_(12)) Deficiency in the Chinese Shar Pei – Evaluation of a Potential Hereditary Etiology  

E-print Network

In recent history, no other dog breed has grown in popularity and/or population size in such a short period of time as is the case for the Chinese Shar Pei in North America. After being introduced to North America in the 1970s, the breed suffered...

Grützner, Niels

2013-12-11

362

Kinetic studies of organocobalt compounds related to vitamin Bââ coenzymes. [B12s  

Microsoft Academic Search

The decomposition of the unstable alkylcobaloxime, ..cap alpha..-phenylethyl-(aquo)cobaloxime, proceeds rapidly in acidic, aqueous methanol leading to the formation of styrene and dimeric organic products. Kinetic studies were carried out at ..mu.. = 1.0 M in the (H\\/sup +\\/) range 0.0014 to 1.0 M. The results obeyed the rate expression -d(CâHâCH(CHâ)Co(dmgH)â(OHâ))-\\/dt = (k\\/sub b\\/ + K\\/sub a\\/K\\/sub H\\/(H\\/sup +\\/)\\/1 + K\\/sub

Gjerde

1982-01-01

363

Metabolic interrelationships between folic acid, vitamin B12 and the citrovorum factor  

E-print Network

microorganisms and animals, including man, has become well established in the past few years. These findings have been summarized in several recent reviews (Pfiffner and Hogan, ? 46 ; Stokstad and Hutchings, f47; Day and Totter, f47 ; Welch, !47 ; Jukes... hand studies by Nichol and Welch ( f50) indicated an increased CP synthesis upon incubation of rat liver slices with PGA and ascorbic acid . In Chapter 3 evidence is pre? sented which offers an explanation for the above discrepancy and briefly...

Doctor, Vasant Manilal

2013-10-04

364

Chemical Methylation of Inorganic Mercury with Methylcobalamin, a Vitamin B12 Analog  

Microsoft Academic Search

Chemical methylation of mercuric chloride with methylcobalamin has been studied. Methylated mercury was detected by gas chromatography; and analysis of the products of the reaction by thin-layer chromatography revealed that the methylation proceeded at a remarkably high rate when methylcobalamin and inorganic mercury were mixed. Dimethylmercury was an initial product of the reaction.

Nobumasa Imura; Eiji Sukegawa; Shoe-Kung Pan; Kiyoshi Nagao; Jong-Yoon Kim; Takao Kwan; Tyunosin Ukita

1971-01-01

365

ORIGINAL ARTICLE Direct exchange of vitamin B12 is demonstrated by  

E-print Network

as algae are found in all marine and fresh- water environments, and may account for up to 50% of the world eutrophication by these elements (for example, by run-off from agriculture, or sediment discharge from rivers). The importance of iron in limiting productivity was demonstrated experimentally by enriching surface waters

Cicuta, Pietro

366

MECHANISTIC STUDIES ON THE VITAMIN B12-CATALYZED DECHLORINATION OF CHLORINATED ALKENES. (U915562)  

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

367

Mechanism of Perfluoroalkyl Halide Toxicity: Catalysis of Perfluoroalkylation by Reduced Forms of Cobalamin (Vitamin B 12 )  

Microsoft Academic Search

Perfluoroalkyl halides (PFHs) are synthetic products widely used in various fields. Perfluorooctyl bromide (PFB) is used in medicine as a component of blood substitutes and for artificial lung ventilation. In both cases, it is considered a completely inert compound acting as a solvent for oxygen. However, there are many reports of PFH-induced intoxication, including lethal cases. Mechanisms underlying toxic effects

N. V. Beda; A. A. Nedospasov

2003-01-01

368

Inhibition of vitamin B12-dependent microbial growth by nitrous oxide  

SciTech Connect

In methionine-free media, nitrous oxide inhibits the growth of an auxotrophic strain of Escherichia coli lacking a cobalamin-independent pathway for the de novo synthesis of methionine. Prototrophic E. coli is similarly inhibited by nitrous oxide if the cobalamin-independent pathway is selectively depressed by sulfanilamide. Nitrous oxide thus effectively inactivates cobalamin-dependent 5-methyltetrahydrofolate-homocysteine methyltransferase in intact bacteria.

Alston, T.A. (Massachusetts General Hospital, Boston (USA))

1991-01-01

369

[Vitamin C].  

PubMed

Vitamin C is a water soluble vitamin which is mainly fresh fruits and vegetables foodborne. Vitamin C deficiency is most often due to a lack of daily amount. Scurvy is characterized by the occurrence of fatigue, myalgia, arthralgia, purpura, bleeding disorders, and later by dental manifestations. Biological signs are nonspecific: anemia, hypocholesterolemia, hypoalbuminemia. Clinical suspicion is confirmed by the decrease in ascorbic acid level (< 2 mg/L). It must be interpreted in light of the acute phase reactants. The treatment is the administration of 1 g of vitamin C per day for 15 days. Vitamin C depletion (ascorbic acid: 2 to 5 mg/L) could induce long-term complications. The recommended dietary allowance of vitamin C protect from these risks. PMID:24298827

Fain, Olivier

2013-10-01

370

B Vitamins  

MedlinePLUS

... process your body uses to get or make energy from the food you eat. They also help form red blood cells. You can get B vitamins from proteins such as fish, poultry, meat, eggs, and dairy products. Leafy green vegetables, beans, and peas also have B vitamins. ...

371

B Vitamins as Regulators of Phytoplankton Dynamics  

NASA Astrophysics Data System (ADS)

Without an adequate supply of dissolved vitamins, many species of phytoplankton do not grow. Additions of inorganic nutrients like phosphorus and nitrogen, and trace metals like iron, are not alone adequate to sustain life-a practical lesson learned quickly by experimental biologists when they try to keep eukaryotic phytoplankton cultures alive in their labs. The reason is that coenzymes such as B vitamins are also required for many metabolic pathways. For example, vitamin B1 serves as a cofactor for a large number of enzymatic systems, including the pyruvate dehydrogenase complex required for the metabolism of carbohydrates (glycolysis) and amino acid synthesis [Vandamme, 1989]. Vitamin B12 is used primarily to assist two enzymes: methionine synthase, which is involved in DNA synthesis, and methylmalonyl CoA mutase, which is required for inorganic carbon assimilation [Lindemans and Abels, 1985].

Panzeca, Caterina; Tovar-Sanchez, Antonio; Agustí, Susana; Reche, Isabel; Duarte, Carlos M.; Taylor, Gordon T.; Sañudo-Wilhelmy, Sergio A.

2006-12-01

372

Water-soluble vitamins in natural plankton (copepods) during two consecutive spring blooms compared to vitamins in Artemia franciscana nauplii and metanauplii  

Microsoft Academic Search

Weight-specific contents of asorbic acid, thiamin, riboflavin, niacin, pantothenic acid, vitamin B6, biotin, folate and vitamin B12 were analysed in natural zooplankton collected from a sea water lagoon in a halibut fry production plant. The samples of\\u000a natural zooplankton were collected from April\\/May to the end of June during two consecutive spring blooms. For comparison,\\u000a the same vitamins were measured

A. Mæland; I. Rønnestad; H. J. Fyhn; L. Berg; R. Waagbø

2000-01-01

373

Influence of vitamin B auxotrophy on nitrogen metabolism in eukaryotic phytoplankton  

PubMed Central

While nitrogen availability is known to limit primary production in large parts of the ocean, vitamin starvation amongst eukaryotic phytoplankton is becoming increasingly recognized as an oceanographically relevant phenomenon. Cobalamin (B12) and thiamine (B1) auxotrophy are widespread throughout eukaryotic phytoplankton, with over 50% of cultured isolates requiring B12 and 20% requiring B1. The frequency of vitamin auxotrophy in harmful algal bloom species is even higher. Instances of colimitation between nitrogen and B vitamins have been observed in marine environments, and interactions between these nutrients have been shown to impact phytoplankton species composition. This review surveys available data, including relevant gene expression patterns, to evaluate the potential for interactive effects of nitrogen and vitamin B12 and B1 starvation in eukaryotic phytoplankton. B12 plays essential roles in amino acid and one-carbon metabolism, while B1 is important for primary carbohydrate and amino acid metabolism and likely useful as an anti-oxidant. Here we will focus on three potential metabolic interconnections between vitamin, nitrogen, and sulfur metabolism that may have ramifications for the role of vitamin and nitrogen scarcities in driving ocean productivity and species composition. These include: (1) B12, B1, and N starvation impacts on osmolyte and antioxidant production, (2) B12 and B1 starvation impacts on polyamine biosynthesis, and (3) influence of B12 and B1 starvation on the diatom urea cycle and amino acid recycling through impacts on the citric acid cycle. We evaluate evidence for these interconnections and identify oceanographic contexts in which each may impact rates of primary production and phytoplankton community composition. Major implications include that B12 and B1 deprivation may impair the ability of phytoplankton to recover from nitrogen starvation and that changes in vitamin and nitrogen availability may synergistically impact harmful algal bloom formation. PMID:23091473

Bertrand, Erin M.; Allen, Andrew E.

2012-01-01

374

Vitamin D Effects on Pregnancy and the Placenta  

PubMed Central

Vitamin D is a pleiotropic secosteroid hormone important for health and disease prevention. The actions of vitamin D are mediated by the vitamin D receptor that binds the active form of vitamin D [1,25(OH)2D] to induce both transcriptional and non-genomic responses. Vitamin D has well known classical functions in calcium uptake and bone metabolism, but more recent work highlights the importance of the nonclassical actions of vitamin D in a variety of cell types. These actions include modulation of the innate and adaptive immune systems and regulation of cell proliferation. Adequate vitamin D intake is essential for maternal and fetal health during pregnancy, and epidemiological data indicate that many pregnant women have sub-optimal vitamin D levels. Notably, vitamin D deficiency correlates with preeclampsia, gestational diabetes mellitus, and bacterial vaginosis, and an increased risk for C-section delivery. Recent work emphasizes the importance of nonclassical roles of vitamin D in pregnancy and the placenta. The placenta produces and responds to vitamin D where vitamin D functions as a modulator of implantation, cytokine production and the immune response to infection. We describe vitamin D metabolism and the cellular responses to vitamin D, and then summarize the role of vitamin D in placental trophoblast, pregnancy and the fetus. PMID:20863562

Shin, Joong Sik; Choi, Mee Yun; Longtine, Mark S.; Nelson, D. Michael

2010-01-01

375

Association of plasma vitamin B6 with risk of colorectal adenoma in a multiethnic case–control study  

Microsoft Academic Search

Circulating level of vitamin B6 has been inversely associated with colorectal cancer (CRC) risk but, unlike for folate, few\\u000a studies have examined the relationship of vitamin B6 to colorectal adenoma, the precursor lesion to most CRCs. We measured\\u000a plasma levels of folate, vitamin B6, and vitamin B12 in 241 patients with pathologically confirmed first occurrence of colorectal\\u000a adenoma and 280

Loïc Le Marchand; Hansong Wang; Jacob Selhub; Thomas M. Vogt; Lance Yokochi; Robert Decker

2011-01-01

376

Sinorhizobium meliloti bluB is necessary for production of 5,6-dimethylbenzimidazole, the lower ligand of B12  

PubMed Central

An insight into a previously unknown step in B12 biosynthesis was unexpectedly obtained through our analysis of a mutant of the symbiotic nitrogen fixing bacterium Sinorhizobium meliloti. This mutant was identified based on its unusually bright fluorescence on plates containing the succinoglycan binding dye calcofluor. The m