Human serum vitamin B12 assay methods — A review

Lee, David S.C.; Griffiths, B. W.

doi:10.1016/s0009-9120(85)80028-x

Cited by 37 publications

(11 citation statements)

References 52 publications

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“…Plasma vitamin B 12 and plasma folic acid were measured using a radioimmunoassay kit (Diagnostic Products Corporation, USA) [25] and plasma total homocysteine was determined using the IMx System (Abbott Laboratories, IL, USA) [26].…”

Section: Methodsmentioning

confidence: 99%

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

et al. 2011

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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.

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Section: Methodsmentioning

confidence: 99%

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

et al. 2011

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“…Folate and vitamin B 12 were estimated by CMIA technology (Abbott Diagnostics, Abbott Park, Ill., USA) [25]. Briefly, 100 µl of plasma was used for analysis of vitamin B 12 and folate.…”

Section: Methodsmentioning

confidence: 99%

Reduced Folate, Increased Vitamin B<sub>12</sub> and Homocysteine Concentrations in Women Delivering Preterm

et al. 2012

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Background and Aim: Maternal nutrition is an important determinant of the duration of pregnancy and fetal growth, and thereby influences pregnancy outcome. Folic acid and vitamin B₁₂ are involved in one-carbon metabolism and are reported to underlie intrauterine programming of adult diseases. Methods: In the present study, the levels of folate, vitamin B₁₂ and homocysteine were measured in mothers delivering preterm (PT; gestation <37 weeks; n = 67), those delivering preterm due to preeclampsia (PT-PE; n = 49) and women delivering at term (control group; n = 76). Results: Increased vitamin B₁₂ and homocysteine levels (p < 0.05 for both) were seen in the PT-PE and PT groups as compared to the controls. In addition, reduced folate levels (p < 0.05) were observed in the PT group. A negative association of maternal plasma homocysteine with birth weight was seen in the idiopathic preterm group. Conclusions: Altered maternal micronutrients and resultant increased homocysteine concentrations exist in women delivering preterm. These alterations may also be partly associated with other factors such as undiagnosed inflammatory conditions or inadequate placentation in some women. Since these micronutrients play an important role in epigenetic regulation of vital genes involved in the fetal programming of adult diseases, further studies need to be undertaken to understand their role in preterm deliveries.

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“…Bovine blood contains haptocorrin (R-protein or transcobalamin-1) that binds vitamin B 12 and interferes with measurement in some older assay systems (Price et al 1992). That difficulty has been overcome in modern assays through the use of extraction procedures that ensure the complete release of vitamin B 12 (Lee and Griffiths 1985). Blood also contains endogenous analogues of cobalamin that can account for a quarter of the measurable vitamin B 12 content in cattle grazing pasture (Halpin et al 1984).…”

Section: Discussionmentioning

confidence: 99%

Lack of production response in grazing dairy cows supplemented withlong-acting injectable vitamin B₁₂

Grace

Knowles

2012

New Zealand Veterinary Journal

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Human serum vitamin B12 assay methods — A review

Cited by 37 publications

References 52 publications

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

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

Reduced Folate, Increased Vitamin B<sub>12</sub> and Homocysteine Concentrations in Women Delivering Preterm

Lack of production response in grazing dairy cows supplemented withlong-acting injectable vitamin B₁₂

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Human serum vitamin B12 assay methods — A review

Cited by 37 publications

References 52 publications

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

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

Reduced Folate, Increased Vitamin B<sub>12</sub> and Homocysteine Concentrations in Women Delivering Preterm

Lack of production response in grazing dairy cows supplemented withlong-acting injectable vitamin B12

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Resources

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Lack of production response in grazing dairy cows supplemented withlong-acting injectable vitamin B₁₂