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methylcobalamin

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https://www.readbyqxmd.com/read/28678474/methylcobalamin-dependent-radical-sam-c-methyltransferase-fom3-recognizes-cytidylyl-2-hydroxyethylphosphonate-and-catalyzes-the-nonstereoselective-c-methylation-in-fosfomycin-biosynthesis
#1
Shusuke Sato, Fumitaka Kudo, Seung-Young Kim, Tomohisa Kuzuyama, Tadashi Eguchi
A methylcobalamin (MeCbl)-dependent radical S-adenosyl-l-methionine (SAM) methyltransferase Fom3 was found to catalyze the C-methylation of cytidylyl-2-hydroxyethylphosphonate (HEP-CMP) to give cytidylyl-2-hydroxypropylphosphonate (HPP-CMP), although it was originally proposed to catalyze the C-methylation of 2-hydroxyethylphosphonate to give 2-hydroxypropylphosphonate in the biosynthesis of a unique C-P bond containing antibiotic fosfomycin in Streptomyces. Unexpectedly, the Fom3 reaction product from HEP-CMP was almost a 1:1 diastereomeric mixture of HPP-CMP, indicating that the C-methylation is not stereoselective...
July 7, 2017: Biochemistry
https://www.readbyqxmd.com/read/28676841/an-in-vitro-model-of-gastric-inflammation-and-treatment-with-cobalamin
#2
T R Elliott, A L Guildford
Pernicious anaemia (PA) is an autoimmune condition where antibodies target intrinsic factor and parietal cells, reducing the patient's ability to absorb cobalamin promoting atrophic gastritis. Treatment guidelines are based on excretion data of hydroxocobalamin from healthy individuals obtained 50 years ago. This manuscript describes the use of phorbol 12-myristate 13-acetate (PMA) to stimulate low grade inflammation in an epithelial colorectal cell line to assess the efficacy of methylcobalamin and hydroxocobalamin...
2017: International Journal of Inflammation
https://www.readbyqxmd.com/read/28667789/efficacy-of-oral-methylcobalamin-in-treatment-of-vitamin-b12-deficiency-anemia-in-children
#3
Deepti Verma, Jagdish Chandra, Praveen Kumar, Shailaja Shukla, Shantanu Sengupta
To demonstrate the efficacy of oral methylcobalamin in treating vitamin B12 (vitB12) deficiency anemia, our prospective observational study enrolled 28 children with both macrocytic anemia and low holotranscobalamin (HoloTC) levels. Their hematological and biochemical parameters pre- and posttreatment at 1 month were compared. Hemoglobin showed mean increase of 2.89 g/dl (P < 0.001), rising above 10 g/dl in 24 patients (85.7%). Reticulocytes peaked at 1 week. Mean fall in mean corpuscular volume of 24...
July 1, 2017: Pediatric Blood & Cancer
https://www.readbyqxmd.com/read/28551266/characterization-of-extracellular-vitamin-b12-producing-lactobacillus-plantarum-strains-and-assessment-of-the-probiotic-potentials
#4
Ping Li, Qing Gu, Lanlan Yang, Yue Yu, Yuejiao Wang
We investigated extracellular vitamin B12-producing Lactobacillus strains and their characteristics in tolerance to environmental stresses, gastric acid and bile salts. Two isolates, Lactobacillus plantarum LZ95 and CY2, showed high extracellular B12 production, 98±15μg/L and 60±9μg/L respectively. Extracellular B12 from LZ95 were identified as adenosylcobalamin and methylcobalamin using a combination of solid phase extraction and reverse-phase HPLC, while that from CY2 was adenosylcobalamin. Both strains grew under environmental stresses, and LZ95 exhibited better tolerance to low temperature and high ethanol concentration...
November 1, 2017: Food Chemistry
https://www.readbyqxmd.com/read/28538514/long-term-outcome-of-4-patients-with-transcobalamin-deficiency-caused-by-2-novel-tcn2-mutations
#5
Marwan Nashabat, Gustavo Maegawa, Peter H Nissen, Ebba Nexo, Hussain Al-Shamrani, Mohammed Al-Owain, Majid Alfadhel
Cobalamin (vitamin B12 [Cbl]) is an essential cofactor for many biochemical pathways. Transcobalamin (TC) is required to internalize Cbl into the cells through membrane receptor-mediated endocytosis. Cbl is then processed in the cytoplasm and mitochondria by complementation factors leading to its active metabolites; methylcobalamin and 5-deoxyadenosyl-cobalamin. Deficiency of TC results in an elevation in methylmalonic acid and homocysteine. Patients usually present with macrocytic anemia, pancytopenia, failure to thrive, gastrointestinal symptoms, and neurological dysfunction...
May 22, 2017: Journal of Pediatric Hematology/oncology
https://www.readbyqxmd.com/read/28483920/cobalamin-riboswitches-exhibit-a-broad-range-of-ability-to-discriminate-between-methylcobalamin-and-adenosylcobalamin
#6
Jacob T Polaski, Samantha M Webster, James E Johnson, Robert T Batey
Riboswitches are a widely distributed class of regulatory RNAs in bacteria that modulate gene expression via small-molecule-induced conformational changes. Generally, these RNA elements are grouped into classes based upon conserved primary and secondary structure and their cognate effector molecule. Although this approach has been very successful in identifying new riboswitch families and defining their distributions, small sequence differences between structurally related RNAs can alter their ligand selectivity and regulatory behavior...
July 14, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28405134/methylcobalamin-in-vitamin-b12-deficiency-to-give-or-not-to-give
#7
Ashwin Kamath, Sudhakar Pemminati
No abstract text is available yet for this article.
January 2017: Journal of Pharmacology & Pharmacotherapeutics
https://www.readbyqxmd.com/read/28223907/comparative-bioavailability-and-utilization-of-particular-forms-of-b12-supplements-with-potential-to-mitigate-b12-related-genetic-polymorphisms
#8
REVIEW
Cristiana Paul, David M Brady
CONTEXT: Three natural forms of vitamin B12 are commercially available: methylcobalamin (MeCbl), adenosylcobalamin (AdCbl), and hydroxycobalamin (OHCbl), all of which have been shown in clinical studies to improve vitamin B12 status. They are bioidentical to the B12 forms occurring in human physiology and animal foods. In contrast, cyanocobalamin (CNCbl), a synthetic B12 compound used for food fortification and in some supplements, occurs only in trace amounts in human tissues as a result of cyanide intake from smoking or other sources...
February 2017: Integrative Medicine
https://www.readbyqxmd.com/read/28179161/electrospun-nanofiber-sheets-incorporating-methylcobalamin-promote-nerve-regeneration-and-functional-recovery-in-a-rat-sciatic-nerve-crush-injury-model
#9
Koji Suzuki, Hiroyuki Tanaka, Mitsuhiro Ebara, Koichiro Uto, Hozo Matsuoka, Shunsuke Nishimoto, Kiyoshi Okada, Tsuyoshi Murase, Hideki Yoshikawa
Peripheral nerve injury is one of common traumas. Although injured peripheral nerves have the capacity to regenerate, axon regeneration proceeds slowly and functional outcomes are often poor. Pharmacological enhancement of regeneration can play an important role in increasing functional recovery. In this study, we developed a novel electrospun nanofiber sheet incorporating methylcobalamin (MeCbl), one of the active forms of vitamin B12 homologues, to deliver it enough locally to the peripheral nerve injury site...
February 5, 2017: Acta Biomaterialia
https://www.readbyqxmd.com/read/28167430/vitamin-b12-in-the-spotlight-again
#10
REVIEW
Jennifer Bridwell-Rabb, Catherine L Drennan
The ability of cobalamin to coordinate different upper axial ligands gives rise to a diversity of reactivity. Traditionally, adenosylcobalamin is associated with radical-based rearrangements, and methylcobalamin with methyl cation transfers. Recently, however, a new role for adenosylcobalamin has been discovered as a light sensor, and a methylcobalamin-dependent enzyme has been identified that is suggested to transfer a methyl anion. Additionally, recent studies have provided a wealth of new information about a third class of cobalamin-dependent enzymes that do not appear to use an upper ligand...
April 2017: Current Opinion in Chemical Biology
https://www.readbyqxmd.com/read/28096758/effects-of-acute-ingestion-of-a-pre-workout-dietary-supplement-with-and-without-p-synephrine-on-resting-energy-expenditure-cognitive-function-and-exercise-performance
#11
Y Peter Jung, Conrad P Earnest, Majid Koozehchian, Elfego Galvan, Ryan Dalton, Dillon Walker, Christopher Rasmussen, Peter S Murano, Mike Greenwood, Richard B Kreider
BACKGROUND: The purpose of this study was to examine the effects of acute ingestion of a pre-workout dietary supplement (PWS) with and without p-synephrine (S) on perceptions of readiness to perform, cognitive function, exercise performance, and markers of safety. METHODS: In a randomized, double-blind, and counterbalanced manner; 25 healthy and recreationally active male and female participants ingested a flavored maltodextrin placebo (PLA), a PWS containing beta-alanine (3 g), creatine nitrate as a salt (2 g), arginine alpha-ketoglutarate (2 g), N-Acetyl-L-Tyrosine (300 mg), caffeine (284 mg), Mucuna pruiriens extract standardized for 15% L-Dopa (15 mg), Vitamin C as Ascorbic Acid (500 mg), niacin (60 mg), folate as folic acid (50 mg), and Vitamin B12 as Methylcobalamin (70 mg) with 2 g of maltodextrin and flavoring; or, the PWS with Citrus aurantium (PWS + S) extract standardized for 30% p-synephrine (20 mg)...
2017: Journal of the International Society of Sports Nutrition
https://www.readbyqxmd.com/read/28096757/effects-of-ingesting-a-pre-workout-dietary-supplement-with-and-without-synephrine-for-8%C3%A2-weeks-on-training-adaptations-in-resistance-trained-males
#12
Y Peter Jung, Conrad P Earnest, Majid Koozehchian, Minye Cho, Nick Barringer, Dillon Walker, Christopher Rasmussen, Mike Greenwood, Peter S Murano, Richard B Kreider
BACKGROUND: The purpose of this study was to examine whether ingesting a pre-workout dietary supplement (PWS) with and without synephrine (S) during training affects training responses in resistance-trained males. METHODS: Resistance-trained males (N = 80) were randomly assigned to supplement their diet in a double-blind manner with either a flavored placebo (PLA); a PWS containing beta-alanine (3 g), creatine nitrate as a salt (2 g), arginine alpha-ketoglutarate (2 g), N-Acetyl-L-Tyrosine (300 mg), caffeine (284 mg), Mucuna pruiriens extract standardized for 15% L-Dopa (15 mg), Vitamin C as Ascorbic Acid (500 mg), niacin (60 mg), folate as folic acid (50 mg), and Vitamin B12 as Methylcobalamin (70 mg); or, the PWS supplement with Citrus aurantium extract containing 20 mg of synephrine (PWS + S) once per day for 8-weeks during training...
2017: Journal of the International Society of Sports Nutrition
https://www.readbyqxmd.com/read/28068938/acupuncture-combined-with-methylcobalamin-for-the-treatment-of-chemotherapy-induced-peripheral-neuropathy-in-patients-with-multiple-myeloma
#13
Xiaoyan Han, Lijuan Wang, Hongfei Shi, Gaofeng Zheng, Jingsong He, Wenjun Wu, Jimin Shi, Guoqing Wei, Weiyan Zheng, Jie Sun, He Huang, Zhen Cai
BACKGROUND: Chemotherapy-induced peripheral neuropathy (CIPN) seriously affects the quality of life of patients with multiple myeloma (MM) as well as the response rate to chemotherapy. Acupuncture has a potential role in the treatment of CIPN, but at present there have been no randomized clinical research studies to analyze the effectiveness of acupuncture for the treatment of CIPN, particularly in MM patients. METHODS: The MM patients (104 individuals) who met the inclusion criteria were randomly assigned into a solely methylcobalamin therapy group (500 μg intramuscular methylcobalamin injections every other day for 20 days; ten injections) followed by 2 months of 500 μg oral methylcobalamin administration, three times per day) and an acupuncture combined with methylcobalamin (Met + Acu) group (methylcobalamin used the same way as above accompanied by three cycles of acupuncture)...
January 9, 2017: BMC Cancer
https://www.readbyqxmd.com/read/27922548/methylcobalamin-prevents-mutant-superoxide-dismutase-1-induced-motor-neuron-death-in-vitro
#14
Shunsuke Ito, Yukina Izumi, Tetsuhiro Niidome, Yuichi Ono
Amyotrophic lateral sclerosis (ALS) is an incurable progressive neurodegenerative disorder that causes motor dysfunction. Treatments and drugs that slow progression of ALS have garnered great interest. In the present study, we show that the vitamin B12 analog methylcobalamin (MBL) effectively and dose dependently prevented embryonic stem cell-derived motor neuron death induced by cocultivation with astrocytes expressing mutant human superoxide dismutase-1 (G93A). Moreover, cotreatment of MBL with a conventional ALS drug, riluzole, further enhanced survival of motor neurons in this in-vitro ALS model...
January 18, 2017: Neuroreport
https://www.readbyqxmd.com/read/27916242/the-effect-of-pregabalin-and-methylcobalamin-combination-on-the-chronic-postthoracotomy-pain-syndrome
#15
RANDOMIZED CONTROLLED TRIAL
Serda Kanbur Metin, Burhan Meydan, Serdar Evman, Talha Dogruyol, Volkan Baysungur
BACKGROUND: Chronic postthoracotomy pain (CPTP) consists of different types of pain. Some characteristics of CPTP are the same as those of recognized neuropathic pain syndromes. We aimed to determine the safety and efficacy of pregabalin and methylcobalamin combination (PG-B12) in comparison with diclofenac potassium (DP) in patients with CPTP. METHODS: One hundred consecutive patients with CPTP after posterolateral/lateral thoracotomy were prospectively randomly assigned and evaluated...
April 2017: Annals of Thoracic Surgery
https://www.readbyqxmd.com/read/27901334/differential-efficacy-of-methylcobalamin-and-alpha-lipoic-acid-treatment-on-negative-and-positive-symptoms-of-type-2-diabetic-peripheral-neuropathy
#16
Yajuan Han, Min Wang, Jie Shen, Zhen Zhang, Min Zhao, Jing Huang, Youming Chen, Zhi Chen, Yulan Hu, Yubing Wang
BACKGROUND: Diabetic hyperglycemia damages peripheral nerves by triggering ischemia, oxidative stress, and inflammation. Alpha-lipoic acid (ALA) and methylcobalamin (MC) are known to improve signs of diabetic peripheral neuropathy (DPN), possibly by enhancing neural and vascular endothelial cell metabolism and antioxidant capacity. We evaluated differences in efficacy following short-term MC or ALA treatment on DPN symptoms to guide clinical drug selection. METHODS: Forty DPN patients were randomly divided into MC and ALA treatment groups (n=20/20) and assessed by the Toronto Clinical Neuropathy Scoring System (TCSS), total symptom score (TSS), visual analog scale (VAS) of positive symptoms, and easy sensory test (EST) for negative symptoms before and after 2 weeks of treatment...
November 30, 2016: Minerva Endocrinologica
https://www.readbyqxmd.com/read/27892441/a-prospective-study-of-commonly-prescribed-drugs-in-the-management-of-neuropathic-pain-and-its-medication-adherence-pattern
#17
R Shrestha, P Silwal, N Basnet, S Shakya Shrestha, R Shrestha, B R Pokharel
Background Neuropathic pain is one of the common complains of patients visiting neurology and orthopedic departments in hospitals. Management of neuropathic pain is difficult and is often symptomatic rather than being curative. Adherence to medication is necessary for pain management to be effective. However, there are various factors related to patient, physician, drug regimen and other socio-economic affecting adherence. Objective To study commonly prescribed drugs in neuropathic pain management and the medication adherence pattern including its associated factors...
January 2016: Kathmandu University Medical Journal (KUMJ)
https://www.readbyqxmd.com/read/27823800/a-randomized-placebo-controlled-trial-of-vitamin-b12-supplementation-to-prevent-cognitive-decline-in-older-diabetic-people-with-borderline-low-serum-vitamin-b12
#18
Timothy Kwok, Jenny Lee, Ronald C Ma, Samuel Y Wong, Kenny Kung, Augustine Lam, C S Ho, Vivian Lee, John Harrison, Linda Lam
BACKGROUND & AIMS: Older diabetic people are at risk of cognitive decline. Vitamin B12 deficiency in older people is associated with cognitive impairment and Alzheimer's disease. Vitamin B12 deficiency may therefore contribute to cognitive decline in older diabetic people. We therefore performed a randomized placebo-controlled trial of vitamin B12 supplementation to prevent cognitive decline in older diabetic people with mild vitamin B12 deficiency. METHODS: 271 diabetic non-demented outpatients aged 70 years or older with plasma vitamin B12 150-300 pmol/L in outpatient clinics were randomly assigned to take either methylcobalamin 1000 μg or two similar looking placebo tablets once daily for 27 months...
October 27, 2016: Clinical Nutrition: Official Journal of the European Society of Parenteral and Enteral Nutrition
https://www.readbyqxmd.com/read/27797190/toward-the-design-of-photoresponsive-conditional-antivitamins-b12-a-transient-absorption-study-of-an-arylcobalamin-and-an-alkynylcobalamin
#19
Nicholas A Miller, Theodore E Wiley, Kenneth G Spears, Markus Ruetz, Christoph Kieninger, Bernhard Kräutler, Roseanne J Sension
Cobalamins are of widespread importance in biology. Both of the cofactors essential for human metabolism, the organocobalamins coenzyme B12 and methylcobalamin, are highly photolabile, as are other alkylcobalamins. The alkynylcobalamin phenylethynylcobalamin (PhEtyCbl) and the arylcobalamin 4-ethylphenylcobalamin (EtPhCbl) with "atypical" Co-C-bonds to unsaturated carbons, were recently designed as metabolically inert cobalamins, classified as "antivitamins B12". The further development of an ideal light-activated or "conditional" antivitamin B12 would require it to be readily converted by light into an active B12 vitamin form...
October 24, 2016: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/27776413/characterization-and-quantitation-of-vitamin-b12-compounds-in-various-chlorella-supplements
#20
Tomohiro Bito, Mariko Bito, Yusuke Asai, Shigeo Takenaka, Yukinori Yabuta, Kazunori Tago, Masato Ohnishi, Toru Mizoguchi, Fumio Watanabe
Vitamin B12 was determined and characterized in 19 dried Chlorella health supplements. Vitamin contents of dried Chlorella cells varied from <0.1 μg to approximately 415 μg per 100 g of dry weight. Subsequent liquid chromatography/electrospray ionization-tandem mass spectrometry analyses showed the presence of inactive corrinoid compounds, a cobalt-free corrinoid, and 5-methoxybenzimidazolyl cyanocobamide (factor IIIm) in four and three high vitamin B12-containing Chlorella tablets, respectively. In four Chlorella tablet types with high and moderate vitamin B12 contents, the coenzyme forms of vitamin B12 5'-deoxyadenosylcobalamin (approximately 32%) and methylcobalamin (approximately 8%) were considerably present, whereas the unnaturally occurring corrinoid cyanocobalamin was present at the lowest concentrations...
November 16, 2016: Journal of Agricultural and Food Chemistry
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