Introduction A wide range of psychiatric symptoms has been associated with pernicious anemia. A number of factors indicate a causal relationship between B12 deficiency and cerebral dysfunction and consequent organic mental change. Deana (1977) demonstrated that vitamin B12 deficiency in the rat has profound effects on several neurotransmitter systems and results in significantly reduced norepin...

The tiny volcanic island of Tristan da Cunha is the most remote inhabited place on Earth. It lies in the South Atlantic, 1,700 miles and a week’s journey by boat from Cape Town, South Africa. The island’s population of 300 is descended from a handful of founders, mostly shipwreck survivors, who settled there in the 19th century. The small number of founders is reflected in the fact that only se...

In clinical practice, the finding of an elevated mean corpuscular volume (MCV), macrocytic anaemia or specific neurological symptoms is often the reason to test for vitamin B12 (B12) deficiency. Use of the MCV as a test for the detection or exclusion of B12 deficiency is only justified if the diagnostic accuracy is sufficiently high. However, the sensitivity and specificity are not well known. ...

Objective: To determine prospectively plasma levels of vitamin B12 in diabetic patients with liver cirrhosis before and 3 months after vitamin administration and its effects on nutritional state of patients. Additionally study a new dosage form of vitamin B12 (buccal film) in compare to traditional one as intramuscular injection. Methods: 120 blood samples were collected from 60 adult cirrhotic...

To investigate the relationship between homocysteine (Hcy) and B vitamins status in the Taiwanese elderly population, an analysis was made of the plasma Hcy levels in elderly persons. The study sample was taken from the Elderly Nutrition and Health Survey in Taiwan (1999-2000) (Elderly NAHSIT) and included 1094 males and 1135 females aged 65-90 years. The results showed that average plasma Hcy ...

Ribonucleotide reductases (RNRs) catalyze the conversion of ribonucleotides to deoxyribonucleotides and are essential for de novo DNA synthesis and repair. Streptomycetes contain genes coding for two RNRs. The class Ia RNR is oxygen dependent, and the class II RNR is oxygen independent and requires coenzyme B12. Either RNR is sufficient for vegetative growth. We show here that the Streptomyces ...

A common polymorphism (775G>C) in the vitamin B12 transport protein, transcobalamin II (TCII), has been identified in which proline replaces arginine at codon 259. We determined the influence of TCII genotype on indices of B12 status, including total serum B12, the amount of B12 bound to TCII (holoTCII), methylmalonic acid, and homocysteine, in 128 healthy older adults (ages 40-88 years). Mean ...

Complete B12 derivatives are natural "molecular switches" as a result of the coordinative switch ("base on" or "base off") of the natural nucleotide base. Certain predesigned B12-nucleotide conjugates were shown recently to behave as "retro riboswitches", in which the nucleotide environment modified the equilibrium between these two isomeric B12 structures. In contrast, the "reverse" situation ...

BACKGROUND Hyperhomocysteinaemia, a risk factor for atherosclerosis, is common in dialysis patients and particularly in those homozygous for a common polymorphism in the 5,10-methylenetetrahydrofolate reductase (MTHFR) gene (C677T transition). B-complex vitamin supplements have been shown to lower plasma total homocysteine (tHcy) concentrations, but the respective effectiveness of folate and or...

1. L-histidine (20 g/kg) added to vitamin B12-deficient and cyanocobalamin-supplemented diets based on soya-bean flour reduced the growth of rats given the vitamin B12-deficient diet but stimulated growth of rats given the cyanocobalamin-supplemented diet. Liver weight (g/kg body-weight)increased, but the protein content of the livers decreased, in rats given histidine supplements. The histidin...