Microbiological assay for vitamin B12 performed in 96-well microtitre plates.

Kelleher, Brian P.; Broin, Sean D.

doi:10.1136/jcp.44.7.592

Cited by 250 publications

(169 citation statements)

References 6 publications

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“…All assays were done by laboratory personnel who were blinded as to the case-control status of the blood samples. Folate concentrations were determined by a Lactobacillus casei microbiological assay (13) and vitamin B 12 concentrations were determined by a Lactobacillus leichmannii microbiological assay (14,15). Both folate and vitamin B 12 assays were adapted to a microtiter plate format and carried out by a robotic workstation (Microlab AT plus 2; Hamilton Bonaduz).…”

Section: Methodsmentioning

confidence: 99%

Circulating Concentrations of Folate and Vitamin B12 in Relation to Prostate Cancer Risk: Results from the European Prospective Investigation into Cancer and Nutrition Study

Johansson

Appleby

Allen

et al. 2008

Cancer Epidemiology, Biomarkers &Amp; Prevention

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Background: Determinants of one-carbon metabolism, such as folate and vitamin B 12 , have been implicated in cancer development. Previous studies have not provided conclusive evidence for the importance of circulating concentrations of folate and vitamin B 12 in prostate cancer etiology. The aim of the present study was to investigate the relationship between prostate cancer risk and circulating concentrations of folate and vitamin B 12 in a large prospective cohort. Methods: We analyzed circulating concentrations of folate and vitamin B 12 in 869 cases and 1,174 controls, individually matched on center, age, and date of recruitment, nested within the European Prospective Investigation into Cancer and Nutrition cohort. Relative risks (RR) for prostate cancer were estimated using conditional logistic regression models. Results: Overall, no significant associations were observed for circulating concentrations of folate (P trend =

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Section: Methodsmentioning

confidence: 99%

Circulating Concentrations of Folate and Vitamin B12 in Relation to Prostate Cancer Risk: Results from the European Prospective Investigation into Cancer and Nutrition Study

Johansson

Appleby

Allen

et al. 2008

Cancer Epidemiology, Biomarkers &Amp; Prevention

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“…23 Folate and vitamin B12 concentrations were determined with a microbiological method using Lactobacillus casei and Lactobacillus leichmannii, respectively, and adapted to a microtiter plate format and carried out by a robotic workstation. 24,25 in addition, three single nucleotide polymorphisms (BHMT 742g>a, MTR 2756a>g, and MTHFR 677c>t) were determined using MalDi-tOF mass spectrometry. 22 to prevent batch effects, samples were analyzed in matched case-control sets, with the position of the case randomized within each set.…”

Section: Blood Sampling and Analysesmentioning

confidence: 99%

Components of One-carbon Metabolism Other than Folate and Colorectal Cancer Risk

et al. 2016

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Background: Despite extensive study, the role of folate in colorectal cancer remains unclear. research has therefore begun to address the role of other elements of the folate-methionine metabolic cycles. this study investigated factors other than folate involved in one-carbon metabolism, i.e., choline, betaine, dimethylglycine, sarcosine, and methionine and relevant polymorphisms, in relation to the risk of colorectal cancer in a population with low intakes and circulating levels of folate. Methods: this was a prospective case-control study of 613 case subjects and 1,190 matched control subjects nested within the population-based northern Sweden Health and Disease Study. We estimated odds ratios (Or) by conditional logistic regression, and marginal risk differences with weighted maximum likelihood estimation using incidence data from the study cohort. Results: Higher plasma concentrations of methionine and betaine were associated with modest colorectal cancer risk reductions (Or [95% confidence interval {ci}] for highest versus lowest tertile: 0.76 [0.57, 0.99] and 0.72 [0.55, 0.94], respectively). estimated marginal risk differences corresponded to approximately 200 fewer colorectal cancer cases per 100,000 individuals on average. We observed no clear associations between choline, dimethylglycine, or sarcosine and colorectal cancer risk. the inverse association of methionine was modified by plasma folate concentrations (Or [95% ci] for highest/ lowest versus lowest/lowest tertile of plasma methionine/folate concentrations 0.39 [0.24, 0.64], P interaction = 0.06). Conclusions: in this population-based, nested case-control study with a long follow-up time from baseline to diagnosis (median: 8.2 years), higher plasma concentrations of methionine and betaine were associated with lower colorectal cancer risk.See Video abstract at http://links.lww.com/eDe/B83. (Epidemiology 2016;27: 787-796) O ne-carbon metabolism is an intracellular network involving the folate and methionine cycles, in which methyl groups and other one-carbon units are transferred to acceptor molecules ( Figure 1). a central role for one-carbon metabolism in cancer development is biologically plausible, as related nucleotide synthesis and methylation reactions including Dna methylation are vital for genome stability and function.the potential role of one-carbon metabolism in colorectal cancer development has been extensively studied, with most research to date focusing on folate. Diets rich in natural folates are associated with reduced risk of colorectal cancer. 1 However, a dual role of folate has been proposed, both preventing and promoting cancer, depending on the dose and timing of exposure. 2,3 Folate is not a one-carbon unit donor per se, but an enzymatic co-factor important for maintenance of the substrate flux in one-carbon metabolism. it might therefore be expected to stabilize the genome of normal mucosa, protecting against cancer, while accelerating the progression of precancerous or malignant lesions. 2 although evidence from animal...

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“…Serum concentrations of folate and vitamin B12 (cobalamin) were measured by microbiological assays (30,31), whereas methionine, choline, betaine, vitamin B2 species [riboflavin and flavin-mononucleotide (FMN)], and vitamin B6 species [pyridoxal 5 0 -phosphate (PLP), pyridoxal (PL), and 4-pyridoxic acid (PA)] were measured in plasma using liquid chromatography-tandem mass spectrometry (32,33). Samples were analyzed in batches of 86 and quality control included six calibration samples, two Figure 1.…”

Section: Biochemical Analysesmentioning

confidence: 99%

Biomarkers Related to One-Carbon Metabolism as Potential Risk Factors for Distal Colorectal Adenomas

Vogel

Schneede

Ueland

et al. 2011

Cancer Epidemiology, Biomarkers &Amp; Prevention

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Background: Efficient one-carbon metabolism, which requires adequate supply of methyl group donors and B-vitamins, may protect against colorectal carcinogenesis. However, plasma folate and vitamins B2 and B12 have inconsistently been associated with colorectal cancer risk, and there have been no previous studies relating plasma concentrations of methionine, choline, and betaine to this outcome.Methods: This study comprised 10,601 individuals, 50 to 64 years of age, participating in the Norwegian Colorectal Cancer Prevention (NORCCAP) screening study. Using logistic regression analyses, we crosssectionally investigated associations between distal colorectal adenoma occurrence-potential precursor lesions of colorectal carcinomas-and plasma concentrations of methyl group donors and B-vitamins, and polymorphisms of genes related to one-carbon metabolism.Results: Screening revealed 1,809 subjects (17.1%) with at least one adenoma. The occurrence of high-risk adenomas (observed in 421 subjects) was inversely associated with plasma concentrations of methionine (highest versus lowest quartile: odds ratio (

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Microbiological assay for vitamin B12 performed in 96-well microtitre plates.

Cited by 250 publications

References 6 publications

Circulating Concentrations of Folate and Vitamin B12 in Relation to Prostate Cancer Risk: Results from the European Prospective Investigation into Cancer and Nutrition Study

Circulating Concentrations of Folate and Vitamin B12 in Relation to Prostate Cancer Risk: Results from the European Prospective Investigation into Cancer and Nutrition Study

Components of One-carbon Metabolism Other than Folate and Colorectal Cancer Risk

Biomarkers Related to One-Carbon Metabolism as Potential Risk Factors for Distal Colorectal Adenomas

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