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 cre...

75Se-selenofolate radioassay was adapted for the purpose of red cell folate measurement. The results of assay of 124 whole blood samples by Lactobacillus casei microbiological assay and by radioassay using the adapted selenofolate method were concordant (r = 0.8). Red cell folate levels by the radioassay were below 170 microgram/1 in people who had haematological features of folate depletion. T...

The photosynthetic coccolithophoid alga, Pleurochrysis (Hymenomonas) carterae, could take up and accumulate exogenous vitamin B12, most of which was converted into the coenzyme forms of vitamin B12. Two vitamin B12-dependent enzyme activities (methylmalonyl-CoA mutase, 2.6+/-0.4 nmol/min/mg protein and methionine synthase, 85.1+/-38.9 pmol/min/mg protein) could be found in a cell homogenate of ...

BACKGROUND The standard screening test for vitamin B12 deficiency, measurement of total plasma vitamin B12, has limitations of sensitivity and specificity. Plasma vitamin B12 bound to transcobalamin (holoTC) is the fraction of total vitamin B12 available for tissue uptake and therefore has been proposed as a potentially useful alternative indicator of vitamin B12 status. METHODS We compared t...

Extensive research on the formation of methionine has implicated vitamin B12 as a cofactor in the final reaction of the biosynthetic sequence. Since plants and fungi do not produce or require B12, an alternate reaction must also exist. It is thus not surprising that Escherichia coli has been found to possess two mechanisms for the methylation of homocysteine to methionine (9). These reactions a...

Background and objectives: Breast carcinoma is one of the most common malignant diseases among women worldwide. In Iraq there are noticeable elevation in incidence rates and prevalence of advanced stages of breast cancer. Cobalamin (vitamin B12) is essential micronutrient involved in one carbon metabolism and DNA methylation, which affects cancer. All of these may be change in breast cancer. Th...

Objective: Oral isotretinoin is the most effective agent in treatment of acne vulgaris. The risk pigmentation due to systemic may be associated with decrease serum levels Vit B12. study aims contribute literature by defining association between increase caused oral [O-ISO] use and low vitamin B12 level [vit-B12]. Methods: In our we evaluated 144 patients, who have facial acnes at medium degree ...

OBJECTIVE To assess the prevalence and clinical features of B12 deficiency in hypothyroid patients and to evaluate clinical response in symptoms to B12 replacement therapy. METHODS One hundred and sixteen hypothyroid patients from our endocrine clinic were evaluated for signs and symptoms of vitamin B12 deficiency. Laboratory parameters including Haemoglobin (Hb), MCV, Vitamin B12 levels and ...

Using comparative analysis of genes, operons, and regulatory elements, we describe the cobalamin (vitamin B12) biosynthetic pathway in available prokaryotic genomes. Here we found a highly conserved RNA secondary structure, the regulatory B12 element, which is widely distributed in the upstream regions of cobalamin biosynthetic/transport genes in eubacteria. In addition, the binding signal (CBL...

Isolated ileal enterocytes incubated with intrinsic factor-[57Co]vitamin B12 (IF-B12) at 37 degrees C took up 25 times more B12 than jejunal enterocytes. Uptake of B12 by ileal cells was dependent upon IF and Ca2+. B12 taken up by ileal enterocytes could be separated into two components: 1) B12 which was retained (E component) and 2) released (R-E component) by chelation of divalent cations. Th...