The bluF gene of Rhodobacter capsulatus is the first gene of the bluFEDCB operon which is involved in late steps of the cobalamin synthesis. To determine the function of the bluF gene product, a bluF::omega-Km mutant strain was constructed and characterized. This vitamin B12 auxotrophic mutant strain shows a 3.5-times higher vitamin B12 requirement under phototrophic growth conditions than unde...

Based on increased demands of strict vegetarians, an investigation of vitamin B12 content in plant sources, was carried out. The vitamin B12 concentration was determined by RP-HPLC with UV detection, after prior matrix isolation by immunoaffinity chromatography (IAC). Vitamin B12 was extracted in the presence of sodium cyanide, to transform all forms of cobalamin into cyanocobalamin. Diode arra...

Cobalamin deficiency is common in patients with Crohn's disease (CD). Intramuscular cobalamin continues to be the standard therapy for the deficiency and maintenance treatment in these patients, although oral route has been demonstrated to be effective in other pathologies with impaired absorption. Our aims were to evaluate the efficacy of oral therapy in the treatment of cobalamin deficiency a...

Orthostatic hypotension in patients with cobalamin (Cbl) deficiency has been reported previously in isolated cases but we are not aware of detailed systematic studies of hemodynamic and autonomic nervous system function in patients with cobalamin deficiency. We investigated hemodynamic and autonomic responses to 60 degrees passive head up tilt (HUT) in 21 patients with vitamin B12 deficiency, 2...

Vitamin B12 deficiency is widespread. Among the population groups at risk are older people, vegetarians, pregnant women and patients with renal or intestinal diseases. The neurological symptoms of vitamin B12 deficiency are unspecific and can be irreversible. Early detection is therefore important. This article reviews the diagnostic performance of the different laboratory markers for vitamin B...

The occurrence in soil of a large group of bacteria which require vitamin B12 has been reported by Lochhead and Thexton (1952). Thirty cultures obtained from 534 isolates showed dependence upon vitamin B12 for growth. Lochhead and Burton (1954) grouped these 30 cultures into 10 types, based on morphological and physiological characteristics. A study of the nature of the vitamin B12 requirements...

During 2001, neurologic impairment resulting from cobalamin (vitamin B12) deficiency was diagnosed in two children in Georgia. The children were breastfed by mothers who followed vegetarian diets. This report summarizes the two cases and provides guidance for health-care providers on identifying and preventing cobalamin deficiency among breastfed infants of vegetarian mothers.

Studies by several investigators (Stokstad, Dornbush, Franklin, Hoffmann, Hutchings, and Jukes, 1949; Skeggs, Nepple, Valentik, Huff, and Wright, 1950) have indicated that an increased growth response was obtained to liver concentrates with thioglycolic or thiomalic acids when vitamin B12 activity was determined with Lactobacillus leichmannii. This was attributed to the prevention, by such redu...

Biermer’s disease also called: Addison’s anemia or in old textbooks, pernicious anemia, is an autoimmune disease, caused by impaired absorption of cobalamin (vitamin B12) owing to the neutralization of intrinsic factor action in the setting of immune atrophic gastritis [1]. In adults and elderly patients, this form of megaloblastic anemia is one of the leading causes of cobalamin deficiency, wi...

Vitamin B12 (cobalamin) deficiency is common in developing countries. Its dermatologic manifestations include hair and nail changes and glossitis. Cases of generalized hyperpigmentation associated with vitamin B12 deficiency have rarely been reported. Localized hyperpigmentation is less frequently described, affecting palms, soles, and flexural areas. We report a rare case of reversible melasma...