I N THE PAST SEVERAL YEARS a number of radioassay procedures for serum vitamin B12 have been described. Each method is based on the fact that unlabeled crystalline B12 will competitively inhibit isotopically labeled B12 (tracer B12) from binding to a specific B12 binding protein(s). Basic to each procedure is the reaction of B12 (labeled and unlabeled) with a limited quantity of binding protein...

I N THE PAST SEVERAL YEARS a number of radioassay procedures for serum vitamin B12 have been described. Each method is based on the fact that unlabeled crystalline B12 will competitively inhibit isotopically labeled B12 (tracer B12) from binding to a specific B12 binding protein(s). Basic to each procedure is the reaction of B12 (labeled and unlabeled) with a limited quantity of binding protein...

T FIAT VITAMIN B12 IN SERUM is l)ound to protein14 has been known since shortly after the isolation of the vitamin. Endogenous vitamin B12 (which may be mainly methyl-Bi2) is bound primarily to an a1-globulin 2.6-10 hut vitamin B12 added to serum in vitro hinds primarily to -globuun (presumably because B12-binding a-globulin is normally almost saturated with endogenous vitamin B12).61#{176} hal...

BACKGROUND The elderly population is particularly at risk for developing vitamin B12-deficiency. Serum cobalamin does not necessarily reflect a normal B12 status. The determination of methylmalonic acid is not available in all laboratories. Issues of sensitivity for holotranscobalamin and the low specificity of total homocysteine limit their utility. The aim of the present study is to establish...

OBJECTIVE The authors found considerably lower plasma total homocysteine (tHcy) concentrations in patients with end-stage renal disease (ESRD) on maintenance hemodialysis, who routinely received high-dose parenteral vitamin B12, than in comparable patients receiving much higher doses of folic acid but only replacement-dose oral vitamin B12. They therefore sought prospective evidence that high-d...

background : increased level of serum homocysteine is one of the risk factor of atherosclerosis. its production related in some sulfur amino acids such as methionine. some important cofactors that are involved in metabolic pathways of this amino acid are folate and vitamin b12. we have assessed the status of methionine, folic acid, and vitamin b12 in some coronary atherosclerotic male patients....

BACKGROUND Newborn screening for total homocysteine (tHcy) in blood may identify babies with vitamin B12 (B12) deficiency or homocystinuria, but data on the causes of increased tHcy in screening samples are sparse. METHODS Serum concentrations of tHcy, cystathionine, methionine, folate, and B12 and the methylenetetrahydrofolate reductase (MTHFR) 677C > T polymorphism were determined in 4992 c...

E NDOGENOUS VITAMIN B12 circulates bound to an alpha-i glycoprotein.”2 Added vitamin binds primarily to a globulin with beta mobility electrophoretically, which may serve mainly a temporary transport function.3’4 This beta globulin readily gives up its vitamin B12 to cells, while the alpha globulin seems to serve as a circulating storage depot.3’5’6 With the exception of some conditions involvi...

OBJECTIVE To assess the status of the vitamin B12 and folate of Chinese women living in northwest China. METHODS A population-based cross-sectional study was conducted in 2008 among Chinese women aged 10-49 years living in Shaanxi province of northwest China. A stratified multistage random sampling method was adopted to obtain a sample of 1170 women. The women were interviewed for collection ...

I N THE PAST SEVERAL YEARS a number of radioassay procedures for serum vitamin B12 have been described. Each method is based on the fact that unlabeled crystalline B12 will competitively inhibit isotopically labeled B12 (tracer B12) from binding to a specific B12 binding protein(s). Basic to each procedure is the reaction of B12 (labeled and unlabeled) with a limited quantity of binding protein...