The pathogenesis of human spontaneous abortion involves a complex interaction of several genetic and environmental factors. The firm association between increased homocysteine concentration and neural tube defects (NTD) has led to the hypothesis that high concentrations of homocysteine might be embryotoxic and lead to decreased fetal viability. There are several genetic polymorphisms that are a...

The [c-lactam] derivative of cobalamin antagonizes vitamin B12 in vivo. Therefore, we investigated its effects in tissue culture to develop a model in which to study vitamin B12-deficient hemopoiesis. HL60 cells were cultured in medium containing either methionine or L-homocysteine thiolactone, and various concentrations of 5-methyltetrahydrofolate or pteroylglutamic acid. In medium with L-homo...

Vitamin B12 deficiency is a well-known cause of megaloblastic anaemia and pancytopenia. However, the incidence in pregnancy is rarely reported. We present a case of a 32-year old multigravid woman who was diagnosed with megaloblastic anaemia since 22 weeks gestation and progressed to develop severe pancytopenia at 30 weeks gestation. She was also diagnosed with vitamin B12 deficiency related to...

A 43-year-old Hispanic male without significant previous medical history was brought to emergency department for syncope following a blood draw to investigate a 40 lbs weight loss during the past 6 months associated with decreased appetite and progressive fatigue. The patient also reported a 1-month history of jaundice. On examination, he was hemodynamically stable and afebrile with pallor and ...

Vitamin B12, Cobyric Acid, Fe(III)Cobalamin, Fe(III)Cobyric Acid, Iron-B12-Analogues, UV/VIS-, NMR-, ESR-Spectra The reaction of hydrogenocobalamin or hydrogenocobyric acid (both isolated from Chromatium vinosum) with iron(III) acetate and iron powder in acetic acid under N 2 at 80 °C leads to the incorporation of iron into these cobalt-free corrinoids. The products, Fe(III)cobalamin and Fe(ni)...

RATIONALE Methylmalonic acidemia (MMA) is a common organic acidemia, mainly due to methylmalonyl-CoA mutase (MCM) or its coenzyme cobalamin (VitB12) metabolic disorders. Cobalamin C (CblC) type is the most frequent inborn error of cobalamin metabolism; it can develop symptoms in childhood and often combine multisystem damage, which leads to methylmalonic acid, propionic acid, methyl citrate, an...

BACKGROUND/AIM Cobalamin and folate are interdependent co-factors of the methionine synthase pathway. This study evaluated the effect of intravenously-administered nitrosylcobalamin (NO-Cbl), a vitamin B12 analog, on serum folate concentrations in healthy dogs. MATERIALS AND METHODS Four dogs received a 10-mg/kg, 20-mg/kg and 40-mg/kg intravenous bolus dose of NO-Cbl, with a 14-day washout pe...

BACKGROUND Vitamin B12 (cobalamin) is a necessary cofactor in methionine and succinyl-CoA metabolism. Studies estimate the deficiency prevalence as high as 30% in the elderly population. Ten to thirty percent of circulating cobalamin is bound to transcobalamin (holotranscobalamin, holoTC) which can readily enter cells and is therefore considered the bioactive form. The objective of our study wa...

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 yea...

Haematology, Guy’s and St Thomas’ NHS Foundation Trust, London, UK Correspondence to: A Hunt [email protected] Cite this as: BMJ 2014;349:g5226 doi: 10.1136/bmj.g5226 Vitamin B12 is an essential cofactor that is integral to methylation processes important in reactions related to DNA and cell metabolism, thus a deficiency may lead to disruption of DNA and cell metabolism and thus have serious c...