Biomaterial Database

Biochemistry and clinical chemistry of vitamin B12 transport and the related diseases. 1984

R Gräsbeck

This review focusses on research performed by the author and coworkers. The absorption, turnover and excretion of cobalamin and the pathogenesis of cobalamin deficiency states are described and the laboratory tests used to diagnose these states are discussed. Topics dealt with in detail include: overall turnover, daily need, enterohepatic circulation and excretion of cobalamin and other corrins . The soluble proteins mediating cobalamin transport and their cellular receptors are described and their nomenclature, isolation, structure and mode of action, the role of calcium in the membrane transport, the evolution of these systems and the analogies with transport systems for other substrates are discussed together with deficiency states, especially fish tapeworm anemia and familial selective vitamin B12 malabsorption with proteinuria. Folate deficiency is a relatively rare cause of megaloblastic anemia in Scandinavia but common in North America and explanations for this difference are suggested. The methods of assaying cobalamin in serum and plasma and the performance of radiovitamin B12 absorption tests are critically evaluated. The measurement of intrinsic factor in gastric juice, serum, amniotic fluid and urine is described.

UI	MeSH Term	Description	Entries
D007408	Intestinal Absorption	Uptake of substances through the lining of the INTESTINES.	Absorption, Intestinal
D007437	Intrinsic Factor	A glycoprotein secreted by the cells of the GASTRIC GLANDS that is required for the absorption of VITAMIN B 12 (cyanocobalamin). Deficiency of intrinsic factor leads to VITAMIN B 12 DEFICIENCY and ANEMIA, PERNICIOUS.	Factor, Intrinsic
D008286	Malabsorption Syndromes	General term for a group of MALNUTRITION syndromes caused by failure of normal INTESTINAL ABSORPTION of nutrients.	Malabsorption Syndrome,Syndrome, Malabsorption,Syndromes, Malabsorption
D008657	Metabolic Clearance Rate	Volume of biological fluid completely cleared of drug metabolites as measured in unit time. Elimination occurs as a result of metabolic processes in the kidney, liver, saliva, sweat, intestine, heart, brain, or other site.	Total Body Clearance Rate,Clearance Rate, Metabolic,Clearance Rates, Metabolic,Metabolic Clearance Rates,Rate, Metabolic Clearance,Rates, Metabolic Clearance
D011956	Receptors, Cell Surface	Cell surface proteins that bind signalling molecules external to the cell with high affinity and convert this extracellular event into one or more intracellular signals that alter the behavior of the target cell (From Alberts, Molecular Biology of the Cell, 2nd ed, pp693-5). Cell surface receptors, unlike enzymes, do not chemically alter their ligands.	Cell Surface Receptor,Cell Surface Receptors,Hormone Receptors, Cell Surface,Receptors, Endogenous Substances,Cell Surface Hormone Receptors,Endogenous Substances Receptors,Receptor, Cell Surface,Surface Receptor, Cell
D004032	Diet	Regular course of eating and drinking adopted by a person or animal.	Diets
D004169	Diphyllobothriasis	Infection with tapeworms of the genus Diphyllobothrium.	Diphyllobothrium Infection,Diphyllobothriases,Diphyllobothrium Infections,Infection, Diphyllobothrium
D004705	Endocytosis	Cellular uptake of extracellular materials within membrane-limited vacuoles or microvesicles. ENDOSOMES play a central role in endocytosis.	Endocytoses
D004909	Erythrocyte Indices	ERYTHROCYTE size and HEMOGLOBIN content or concentration, usually derived from ERYTHROCYTE COUNT; BLOOD hemoglobin concentration; and HEMATOCRIT. The indices include the mean corpuscular volume (MCV), the mean corpuscular hemoglobin (MCH), and the mean corpuscular hemoglobin concentration (MCHC).	Erythrocyte Hemoglobin, Mean Cell,Erythrocyte Size Determination,Erythrocyte Volume, Mean Cell,Hemoglobin, Erythrocyte, Mean Cell,Mean Corpuscular Volume,Red Cell Indices,Erythrocyte Diameter,Erythrocyte Index,Erythrocyte Indexes,Erythrocyte Thickness,Mean Cell Hemoglobin Concentration,Mean Cell Volume,Mean Corpuscular Hemoglobin,Mean Corpuscular Hemoglobulin Concentration,Red Cell Distribution Width,Red Cell Index,Red Cell Indexes,Cell Volumes, Mean,Corpuscular Volumes, Mean,Determination, Erythrocyte Size,Determinations, Erythrocyte Size,Diameter, Erythrocyte,Diameters, Erythrocyte,Erythrocyte Diameters,Erythrocyte Size Determinations,Hemoglobin, Mean Corpuscular,Hemoglobins, Mean Corpuscular,Index, Erythrocyte,Index, Red Cell,Indexes, Erythrocyte,Indexes, Red Cell,Indices, Erythrocyte,Indices, Red Cell,Mean Cell Volumes,Mean Corpuscular Hemoglobins,Mean Corpuscular Volumes,Size Determination, Erythrocyte,Size Determinations, Erythrocyte,Thickness, Erythrocyte,Volume, Mean Cell,Volume, Mean Corpuscular,Volumes, Mean Cell,Volumes, Mean Corpuscular
D005492	Folic Acid	A member of the vitamin B family that stimulates the hematopoietic system. It is present in the liver and kidney and is found in mushrooms, spinach, yeast, green leaves, and grasses (POACEAE). Folic acid is used in the treatment and prevention of folate deficiencies and megaloblastic anemia.	Pteroylglutamic Acid,Vitamin M,Folacin,Folate,Folic Acid, (D)-Isomer,Folic Acid, (DL)-Isomer,Folic Acid, Calcium Salt (1:1),Folic Acid, Monopotassium Salt,Folic Acid, Monosodium Salt,Folic Acid, Potassium Salt,Folic Acid, Sodium Salt,Folvite,Vitamin B9,B9, Vitamin