Iron: A metallic element with atomic symbol Fe, atomic number 26, and atomic weight 55.85. It is an essential constituent of HEMOGLOBINS; CYTOCHROMES; and IRON-BINDING PROTEINS. It plays a role in cellular redox reactions and in the transport of OXYGEN.Iron Chelating Agents: Organic chemicals that form two or more coordination links with an iron ion. Once coordination has occurred, the complex formed is called a chelate. The iron-binding porphyrin group of hemoglobin is an example of a metal chelate found in biological systems.Iron Overload: An excessive accumulation of iron in the body due to a greater than normal absorption of iron from the gastrointestinal tract or from parenteral injection. This may arise from idiopathic hemochromatosis, excessive iron intake, chronic alcoholism, certain types of refractory anemia, or transfusional hemosiderosis. (From Churchill's Illustrated Medical Dictionary, 1989)Iron, Dietary: Iron or iron compounds used in foods or as food. Dietary iron is important in oxygen transport and the synthesis of the iron-porphyrin proteins hemoglobin, myoglobin, cytochromes, and cytochrome oxidase. Insufficient amounts of dietary iron can lead to iron-deficiency anemia.Iron Isotopes: Stable iron atoms that have the same atomic number as the element iron, but differ in atomic weight. Fe-54, 57, and 58 are stable iron isotopes.Iron Radioisotopes: Unstable isotopes of iron that decay or disintegrate emitting radiation. Fe atoms with atomic weights 52, 53, 55, and 59-61 are radioactive iron isotopes.Ferritins: Iron-containing proteins that are widely distributed in animals, plants, and microorganisms. Their major function is to store IRON in a nontoxic bioavailable form. Each ferritin molecule consists of ferric iron in a hollow protein shell (APOFERRITINS) made of 24 subunits of various sequences depending on the species and tissue types.Iron Compounds: Organic and inorganic compounds that contain iron as an integral part of the molecule.Ferric Compounds: Inorganic or organic compounds containing trivalent iron.Anemia, Iron-Deficiency: Anemia characterized by decreased or absent iron stores, low serum iron concentration, low transferrin saturation, and low hemoglobin concentration or hematocrit value. The erythrocytes are hypochromic and microcytic and the iron binding capacity is increased.Transferrin: An iron-binding beta1-globulin that is synthesized in the LIVER and secreted into the blood. It plays a central role in the transport of IRON throughout the circulation. A variety of transferrin isoforms exist in humans, including some that are considered markers for specific disease states.Iron Regulatory Protein 1: A multifunctional iron-sulfur protein that is both an iron regulatory protein and cytoplasmic form of aconitate hydratase. It binds to iron regulatory elements found on mRNAs involved in iron metabolism and regulates their translation. Its RNA binding ability and its aconitate hydrolase activity are dependent upon availability of IRON.Ferrous Compounds: Inorganic or organic compounds that contain divalent iron.Iron Metabolism Disorders: Disorders in the processing of iron in the body: its absorption, transport, storage, and utilization. (From Mosby's Medical, Nursing, & Allied Health Dictionary, 4th ed)Iron Regulatory Protein 2: A multifunctional iron-sulfur protein that is both an iron regulatory protein and cytoplasmic form of aconitate hydratase. It binds to iron regulatory elements found on mRNAs involved in iron metabolism and regulates their translation. Its rate of degradation is increased in the presence of IRON.Deferoxamine: Natural product isolated from Streptomyces pilosus. It forms iron complexes and is used as a chelating agent, particularly in the mesylate form.Siderophores: Low-molecular-weight compounds produced by microorganisms that aid in the transport and sequestration of ferric iron. (The Encyclopedia of Molecular Biology, 1994)Receptors, Transferrin: Membrane glycoproteins found in high concentrations on iron-utilizing cells. They specifically bind iron-bearing transferrin, are endocytosed with its ligand and then returned to the cell surface where transferrin without its iron is released.Hepcidins: Forms of hepcidin, a cationic amphipathic peptide synthesized in the liver as a prepropeptide which is first processed into prohepcidin and then into the biologically active hepcidin forms, including in human the 20-, 22-, and 25-amino acid residue peptide forms. Hepcidin acts as a homeostatic regulators of iron metabolism and also possesses antimicrobial activity.Iron-Dextran Complex: A complex of ferric oxyhydroxide with dextrans of 5000 to 7000 daltons in a viscous solution containing 50 mg/ml of iron. It is supplied as a parenteral preparation and is used as a hematinic. (Goodman and Gilman's The Pharmacological Basis of Therapeutics, 8th ed, p1292)Anemia, Hypochromic: Anemia characterized by a decrease in the ratio of the weight of hemoglobin to the volume of the erythrocyte, i.e., the mean corpuscular hemoglobin concentration is less than normal. The individual cells contain less hemoglobin than they could have under optimal conditions. Hypochromic anemia may be caused by iron deficiency from a low iron intake, diminished iron absorption, or excessive iron loss. It can also be caused by infections or other diseases, therapeutic drugs, lead poisoning, and other conditions. (Stedman, 25th ed; from Miale, Laboratory Medicine: Hematology, 6th ed, p393)Hemochromatosis: A disorder of iron metabolism characterized by a triad of HEMOSIDEROSIS; LIVER CIRRHOSIS; and DIABETES MELLITUS. It is caused by massive iron deposits in parenchymal cells that may develop after a prolonged increase of iron absorption. (Jablonski's Dictionary of Syndromes & Eponymic Diseases, 2d ed)Nonheme Iron Proteins: Proteins, usually acting in oxidation-reduction reactions, containing iron but no porphyrin groups. (Lehninger, Principles of Biochemistry, 1993, pG-10)Hemoglobins: The oxygen-carrying proteins of ERYTHROCYTES. They are found in all vertebrates and some invertebrates. The number of globin subunits in the hemoglobin quaternary structure differs between species. Structures range from monomeric to a variety of multimeric arrangements.Iron-Binding Proteins: Proteins that specifically bind to IRON.Cation Transport Proteins: Membrane proteins whose primary function is to facilitate the transport of positively charged molecules (cations) across a biological membrane.Iron-Regulatory Proteins: Proteins that regulate cellular and organismal iron homeostasis. They play an important biological role by maintaining iron levels that are adequate for metabolic need, but below the toxicity threshold.Apoferritins: The protein components of ferritins. Apoferritins are shell-like structures containing nanocavities and ferroxidase activities. Apoferritin shells are composed of 24 subunits, heteropolymers in vertebrates and homopolymers in bacteria. In vertebrates, there are two types of subunits, light chain and heavy chain. The heavy chain contains the ferroxidase activity.HemosiderinHeme: The color-furnishing portion of hemoglobin. It is found free in tissues and as the prosthetic group in many hemeproteins.Antimicrobial Cationic Peptides: Small cationic peptides that are an important component, in most species, of early innate and induced defenses against invading microbes. In animals they are found on mucosal surfaces, within phagocytic granules, and on the surface of the body. They are also found in insects and plants. Among others, this group includes the DEFENSINS, protegrins, tachyplesins, and thionins. They displace DIVALENT CATIONS from phosphate groups of MEMBRANE LIPIDS leading to disruption of the membrane.Glucaric Acid: A sugar acid derived from D-glucose in which both the aldehydic carbon atom and the carbon atom bearing the primary hydroxyl group are oxidized to carboxylic acid groups.Iron Carbonyl Compounds: Complex of iron atoms chelated with carbonyl ions.CeruloplasminFMN Reductase: An enzyme that utilizes NADH or NADPH to reduce FLAVINS. It is involved in a number of biological processes that require reduced flavin for their functions such as bacterial bioluminescence. Formerly listed as EC 1.6.8.1 and EC 1.5.1.29.Chelation Therapy: Therapy of heavy metal poisoning using agents which sequester the metal from organs or tissues and bind it firmly within the ring structure of a new compound which can be eliminated from the body.Intestinal Absorption: Uptake of substances through the lining of the INTESTINES.Ferrozine: A ferroin compound that forms a stable magenta-colored solution with the ferrous ion. The complex has an absorption peak at 562 nm and is used as a reagent and indicator for iron.Anemia: A reduction in the number of circulating ERYTHROCYTES or in the quantity of HEMOGLOBIN.beta-Thalassemia: A disorder characterized by reduced synthesis of the beta chains of hemoglobin. There is retardation of hemoglobin A synthesis in the heterozygous form (thalassemia minor), which is asymptomatic, while in the homozygous form (thalassemia major, Cooley's anemia, Mediterranean anemia, erythroblastic anemia), which can result in severe complications and even death, hemoglobin A synthesis is absent.Iron-Sulfur Proteins: A group of proteins possessing only the iron-sulfur complex as the prosthetic group. These proteins participate in all major pathways of electron transport: photosynthesis, respiration, hydroxylation and bacterial hydrogen and nitrogen fixation.Biological Availability: The extent to which the active ingredient of a drug dosage form becomes available at the site of drug action or in a biological medium believed to reflect accessibility to a site of action.Food, Fortified: Any food that has been supplemented with essential nutrients either in quantities that are greater than those present normally, or which are not present in the food normally. Fortified food includes also food to which various nutrients have been added to compensate for those removed by refinement or processing. (From Segen, Dictionary of Modern Medicine, 1992)Pyridones: Pyridine derivatives with one or more keto groups on the ring.Magnetite Nanoparticles: Synthesized magnetic particles under 100 nanometers possessing many biomedical applications including DRUG DELIVERY SYSTEMS and CONTRAST AGENTS. The particles are usually coated with a variety of polymeric compounds.Siderosis: A form of pneumoconiosis resulting from inhalation of iron in the mining dust or welding fumes.Phlebotomy: The techniques used to draw blood from a vein for diagnostic purposes or for treatment of certain blood disorders such as erythrocytosis, hemochromatosis, polycythemia vera, and porphyria cutanea tarda.Absorption: The physical or physiological processes by which substances, tissue, cells, etc. take up or take in other substances or energy.Homeostasis: The processes whereby the internal environment of an organism tends to remain balanced and stable.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).Zinc: A metallic element of atomic number 30 and atomic weight 65.38. It is a necessary trace element in the diet, forming an essential part of many enzymes, and playing an important role in protein synthesis and in cell division. Zinc deficiency is associated with ANEMIA, short stature, HYPOGONADISM, impaired WOUND HEALING, and geophagia. It is known by the symbol Zn.Oxidation-Reduction: A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471).Nitrilotriacetic Acid: A derivative of acetic acid, N(CH2COOH)3. It is a complexing (sequestering) agent that forms stable complexes with Zn2+. (From Miall's Dictionary of Chemistry, 5th ed.)Ferrosoferric Oxide: Iron (II,III) oxide (Fe3O4). It is a black ore of IRON that forms opaque crystals and exerts strong magnetism.Aconitate Hydratase: An enzyme that catalyzes the reversible hydration of cis-aconitate to yield citrate or isocitrate. It is one of the citric acid cycle enzymes. EC 4.2.1.3.Copper: A heavy metal trace element with the atomic symbol Cu, atomic number 29, and atomic weight 63.55.Liver: A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.Spectroscopy, Mossbauer: A spectroscopic technique which uses the Mossbauer effect (inelastic scattering of gamma radiation resulting from interaction with heavy nuclei) to monitor the small variations in the interaction between an atomic nucleus and its environment. Such variations may be induced by changes in temperature, pressure, chemical state, molecular conformation, molecular interaction, or physical site. It is particularly useful for studies of structure-activity relationship in metalloproteins, mobility of heavy metals, and the state of whole tissue and cell membranes.Enterobactin: An iron-binding cyclic trimer of 2,3-dihydroxy-N-benzoyl-L-serine. It is produced by E COLI and other enteric bacteria.Hematocrit: The volume of packed RED BLOOD CELLS in a blood specimen. The volume is measured by centrifugation in a tube with graduated markings, or with automated blood cell counters. It is an indicator of erythrocyte status in disease. For example, ANEMIA shows a low value; POLYCYTHEMIA, a high value.Dietary Supplements: Products in capsule, tablet or liquid form that provide dietary ingredients, and that are intended to be taken by mouth to increase the intake of nutrients. Dietary supplements can include macronutrients, such as proteins, carbohydrates, and fats; and/or MICRONUTRIENTS, such as VITAMINS; MINERALS; and PHYTOCHEMICALS.Protoporphyrins: Porphyrins with four methyl, two vinyl, and two propionic acid side chains attached to the pyrrole rings. Protoporphyrin IX occurs in hemoglobin, myoglobin, and most of the cytochromes.Hemosiderosis: Conditions in which there is a generalized increase in the iron stores of body tissues, particularly of liver and the MONONUCLEAR PHAGOCYTE SYSTEM, without demonstrable tissue damage. The name refers to the presence of stainable iron in the tissue in the form of hemosiderin.Ascorbic Acid: A six carbon compound related to glucose. It is found naturally in citrus fruits and many vegetables. Ascorbic acid is an essential nutrient in human diets, and necessary to maintain connective tissue and bone. Its biologically active form, vitamin C, functions as a reducing agent and coenzyme in several metabolic pathways. Vitamin C is considered an antioxidant.Nutritional Status: State of the body in relation to the consumption and utilization of nutrients.Bacterial Proteins: Proteins found in any species of bacterium.Phytic Acid: Complexing agent for removal of traces of heavy metal ions. It acts also as a hypocalcemic agent.Lactoferrin: An iron-binding protein that was originally characterized as a milk protein. It is widely distributed in secretory fluids and is found in the neutrophilic granules of LEUKOCYTES. The N-terminal part of lactoferrin possesses a serine protease which functions to inactivate the TYPE III SECRETION SYSTEM used by bacteria to export virulence proteins for host cell invasion.2,2'-Dipyridyl: A reagent used for the determination of iron.Conalbumin: A glycoprotein albumin from hen's egg white with strong iron-binding affinity.Electron Spin Resonance Spectroscopy: A technique applicable to the wide variety of substances which exhibit paramagnetism because of the magnetic moments of unpaired electrons. The spectra are useful for detection and identification, for determination of electron structure, for study of interactions between molecules, and for measurement of nuclear spins and moments. (From McGraw-Hill Encyclopedia of Science and Technology, 7th edition) Electron nuclear double resonance (ENDOR) spectroscopy is a variant of the technique which can give enhanced resolution. Electron spin resonance analysis can now be used in vivo, including imaging applications such as MAGNETIC RESONANCE IMAGING.Biological Transport: The movement of materials (including biochemical substances and drugs) through a biological system at the cellular level. The transport can be across cell membranes and epithelial layers. It also can occur within intracellular compartments and extracellular compartments.Duodenum: The shortest and widest portion of the SMALL INTESTINE adjacent to the PYLORUS of the STOMACH. It is named for having the length equal to about the width of 12 fingers.Hematinics: Agents which improve the quality of the blood, increasing the hemoglobin level and the number of erythrocytes. They are used in the treatment of anemias.Bloodletting: Puncture of a vein to draw blood for therapeutic purposes. Bloodletting therapy has been used in Talmudic and Indian medicine since the medieval time, and was still practiced widely in the 18th and 19th centuries. Its modern counterpart is PHLEBOTOMY.Erythropoiesis: The production of red blood cells (ERYTHROCYTES). In humans, erythrocytes are produced by the YOLK SAC in the first trimester; by the liver in the second trimester; by the BONE MARROW in the third trimester and after birth. In normal individuals, the erythrocyte count in the peripheral blood remains relatively constant implying a balance between the rate of erythrocyte production and rate of destruction.Ferrichrome: A cyclic peptide consisting of three residues of delta-N-hydroxy-delta-N-acetylornithine. It acts as an iron transport agent in Ustilago sphaerogena.Trace Elements: A group of chemical elements that are needed in minute quantities for the proper growth, development, and physiology of an organism. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Oxidative Stress: A disturbance in the prooxidant-antioxidant balance in favor of the former, leading to potential damage. Indicators of oxidative stress include damaged DNA bases, protein oxidation products, and lipid peroxidation products (Sies, Oxidative Stress, 1991, pxv-xvi).Deficiency Diseases: A condition produced by dietary or metabolic deficiency. The term includes all diseases caused by an insufficient supply of essential nutrients, i.e., protein (or amino acids), vitamins, and minerals. It also includes an inadequacy of calories. (From Dorland, 27th ed; Stedman, 25th ed)Membrane Proteins: Proteins which are found in membranes including cellular and intracellular membranes. They consist of two types, peripheral and integral proteins. They include most membrane-associated enzymes, antigenic proteins, transport proteins, and drug, hormone, and lectin receptors.Pregnancy Complications, Hematologic: The co-occurrence of pregnancy and a blood disease (HEMATOLOGIC DISEASES) which involves BLOOD CELLS or COAGULATION FACTORS. The hematologic disease may precede or follow FERTILIZATION and it may or may not have a deleterious effect on the pregnant woman or FETUS.Thalassemia: A group of hereditary hemolytic anemias in which there is decreased synthesis of one or more hemoglobin polypeptide chains. There are several genetic types with clinical pictures ranging from barely detectable hematologic abnormality to severe and fatal anemia.Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Chelating Agents: Chemicals that bind to and remove ions from solutions. Many chelating agents function through the formation of COORDINATION COMPLEXES with METALS.Gene Expression Regulation, Bacterial: Any of the processes by which cytoplasmic or intercellular factors influence the differential control of gene action in bacteria.Erythropoietin: Glycoprotein hormone, secreted chiefly by the KIDNEY in the adult and the LIVER in the FETUS, that acts on erythroid stem cells of the BONE MARROW to stimulate proliferation and differentiation.Edetic Acid: A chelating agent that sequesters a variety of polyvalent cations such as CALCIUM. It is used in pharmaceutical manufacturing and as a food additive.Benzoates: Derivatives of BENZOIC ACID. Included under this heading are a broad variety of acid forms, salts, esters, and amides that contain the carboxybenzene structure.Manganese: A trace element with atomic symbol Mn, atomic number 25, and atomic weight 54.94. It is concentrated in cell mitochondria, mostly in the pituitary gland, liver, pancreas, kidney, and bone, influences the synthesis of mucopolysaccharides, stimulates hepatic synthesis of cholesterol and fatty acids, and is a cofactor in many enzymes, including arginase and alkaline phosphatase in the liver. (From AMA Drug Evaluations Annual 1992, p2035)Hemin: Chloro(7,12-diethenyl-3,8,13,17-tetramethyl-21H,23H-porphine-2,18-dipropanoato(4-)-N(21),N(22),N(23),N(24)) ferrate(2-) dihydrogen.Mutation: Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.Hemeproteins: Proteins that contain an iron-porphyrin, or heme, prosthetic group resembling that of hemoglobin. (From Lehninger, Principles of Biochemistry, 1982, p480)Ferrocyanides: Inorganic salts of the hypothetical acid ferrocyanic acid (H4Fe(CN)6).Kinetics: The rate dynamics in chemical or physical systems.Citric Acid: A key intermediate in metabolism. It is an acid compound found in citrus fruits. The salts of citric acid (citrates) can be used as anticoagulants due to their calcium chelating ability.Micronutrients: Essential dietary elements or organic compounds that are required in only small quantities for normal physiologic processes to occur.Histocompatibility Antigens Class I: Membrane glycoproteins consisting of an alpha subunit and a BETA 2-MICROGLOBULIN beta subunit. In humans, highly polymorphic genes on CHROMOSOME 6 encode the alpha subunits of class I antigens and play an important role in determining the serological specificity of the surface antigen. Class I antigens are found on most nucleated cells and are generally detected by their reactivity with alloantisera. These antigens are recognized during GRAFT REJECTION and restrict cell-mediated lysis of virus-infected cells.Transferrin-Binding Proteins: A class of carrier proteins that bind to TRANSFERRIN. Many strains of pathogenic bacteria utilize transferrin-binding proteins to acquire their supply of iron from serum.Blood Transfusion: The introduction of whole blood or blood component directly into the blood stream. (Dorland, 27th ed)Spectrophotometry, Atomic: Spectrophotometric techniques by which the absorption or emmision spectra of radiation from atoms are produced and analyzed.Apoproteins: The protein components of a number of complexes, such as enzymes (APOENZYMES), ferritin (APOFERRITINS), or lipoproteins (APOLIPOPROTEINS).Mononuclear Phagocyte System: Mononuclear cells with pronounced phagocytic ability that are distributed extensively in lymphoid and other organs. It includes MACROPHAGES and their precursors; PHAGOCYTES; KUPFFER CELLS; HISTIOCYTES; DENDRITIC CELLS; LANGERHANS CELLS; and MICROGLIA. The term mononuclear phagocyte system has replaced the former reticuloendothelial system, which also included less active phagocytic cells such as fibroblasts and endothelial cells. (From Illustrated Dictionary of Immunology, 2d ed.)Hemoglobinometry: Measurement of hemoglobin concentration in blood.Magnetics: The study of MAGNETIC PHENOMENA.Erythrocytes: Red blood cells. Mature erythrocytes are non-nucleated, biconcave disks containing HEMOGLOBIN whose function is to transport OXYGEN.Dextrans: A group of glucose polymers made by certain bacteria. Dextrans are used therapeutically as plasma volume expanders and anticoagulants. They are also commonly used in biological experimentation and in industry for a wide variety of purposes.Oxidoreductases: The class of all enzymes catalyzing oxidoreduction reactions. The substrate that is oxidized is regarded as a hydrogen donor. The systematic name is based on donor:acceptor oxidoreductase. The recommended name will be dehydrogenase, wherever this is possible; as an alternative, reductase can be used. Oxidase is only used in cases where O2 is the acceptor. (Enzyme Nomenclature, 1992, p9)Flour: Ground up seed of WHEAT.Spectrum Analysis: The measurement of the amplitude of the components of a complex waveform throughout the frequency range of the waveform. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Metalloproteins: Proteins that have one or more tightly bound metal ions forming part of their structure. (Dorland, 28th ed)Sulfur: An element that is a member of the chalcogen family. It has an atomic symbol S, atomic number 16, and atomic weight [32.059; 32.076]. It is found in the amino acids cysteine and methionine.Hydroxyl Radical: The univalent radical OH. Hydroxyl radical is a potent oxidizing agent.Porphyrins: A group of compounds containing the porphin structure, four pyrrole rings connected by methine bridges in a cyclic configuration to which a variety of side chains are attached. The nature of the side chain is indicated by a prefix, as uroporphyrin, hematoporphyrin, etc. The porphyrins, in combination with iron, form the heme component in biologically significant compounds such as hemoglobin and myoglobin.Oxygen: An element with atomic symbol O, atomic number 8, and atomic weight [15.99903; 15.99977]. It is the most abundant element on earth and essential for respiration.Hydrogen-Ion Concentration: The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH = log 1/2[1/(H+)], where (H+) is the hydrogen ion concentration in gram equivalents per liter of solution. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Infant Food: Food processed and manufactured for the nutritional health of children in their first year of life.Amino Acid Sequence: The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.Erythrocyte Count: The number of RED BLOOD CELLS per unit volume in a sample of venous BLOOD.Hydrogen Peroxide: A strong oxidizing agent used in aqueous solution as a ripening agent, bleach, and topical anti-infective. It is relatively unstable and solutions deteriorate over time unless stabilized by the addition of acetanilide or similar organic materials.