Since the demonstration of the dual nature of vitamin B in 1926 (1, 2) which has been amply confirmed in recent years (35), there has been no satisfactory method for the separation of the heat-labile antineuritic (vitamin B,) from the more heat-stable growth-promoting (vitamin B,) component of the vitamin B complex. There are numerous experiments recorded in the lit,erature indicating that at l...

Serum vitamin B-12 concentrations are measured to assess the presence of its deficiency in patients presenting with haematolological, neurological, and neuropsychiatric abnormalities. Replacement therapy is instituted promptly, particularly to prevent irreversible neurological and cognitive dysfunction. I present two cases with paradoxical vitamin B-12 results, which highlight the fallacies of ...

Kloeckera apiculata, a vitamin B-6-dependent yeast, grows in the presence of 3-hydroxy-2,4,5-trihydroxymethylpyridine in vitamin B-6-free media. On a molar basis the growth-promoting activity of this compound is approximately one-tenth that of other forms of vitamin B-6. [G-3H]3-Hydroxy-2,4,5-trihydroxymethylpyridine is converted into radioactive vitamin B-6 compounds of the same specific radio...

BACKGROUND Vitamin B-12 deficiency is usually accompanied by elevated concentrations of serum total homocysteine (tHcy) and methylmalonic acid (MMA). Folate deficiency also results in elevated tHcy. Measurement of these metabolites can be used to screen for functional vitamin B-12 or folate deficiency. OBJECTIVE We assessed the prevalence of vitamin B-12 and folate deficiency in a population-...

BACKGROUND The effects of vitamin B-6 status on steady-state kinetics of homocysteine metabolism in humans are unclear. OBJECTIVE The objective was to determine the effects of dietary vitamin B-6 restriction on the rates of homocysteine remethylation and synthesis in healthy humans. DESIGN Primed, constant infusions of [(13)C(5)]methionine, [3-(13)C]serine, and [(2)H(3)]leucine were conduct...

In this paper the term vitamin B,, is used to signify vitamin B,, activity measured by microbiological assay with Lactobacillus leichmannii as test organism. The concentration of vitamin B,, in the serum of the rabbit is remarkably high compared with that of some other species. In man and the rat the highest normal values found in this laboratory have been 0.001 and 0-00088 pg/ml respectively (...

Bendamustine hydrochloride is an alkylating antitumor agent with a good efficacy in the treatment of chronic lymphocytic leukemia (CLL) and B-cell non-Hodgkin's lymphoma (B-NHL). Under the stressed conditions, two degradant impurities in bendamustine hydrochloride drug product were detected by high-performance liquid chromatography. These two degradant impurities were isolated from preparative ...

BACKGROUND High homocysteine and low B vitamin concentrations have been linked to the risk of vascular disease, stroke, and dementia and are relatively common in older adults. OBJECTIVE We assessed the effect of breakfast cereal fortified with folic acid, vitamin B-6, and vitamin B-12 on vitamin and homocysteine status. DESIGN A randomized, double-blind trial was conducted in 189 volunteers...

Background: Vitamin B-12 deficiency is usually accompanied by elevated concentrations of serum total homocysteine (tHcy) and methylmalonic acid (MMA). Folate deficiency also results in elevated tHcy. Measurement of these metabolites can be used to screen for functional vitamin B-12 or folate deficiency. Objective: We assessed the prevalence of vitamin B-12 and folate deficiency in a population-...

In order to identify the effects of vitamin B 12 and folic acid in reducing methanolinduced retinopathy, ERG waves were compared before and after methanol intoxication in rabbits. In this study 34 rabbits were divided into 4 groups. All groups received 4 g/kg of methanol intraperitoneally. In addition, the second, third and fourth groups received vitamin B 12 injection, oral folic acid and ...