The reversibly oxidized form of ascorbic acid. It is the lactone of 2,3-DIKETOGULONIC ACID and has antiscorbutic activity in man on oral ingestion.

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.

Inorganic derivatives of phosphorus trihydroxide (P(OH)3) and its tautomeric form dihydroxyphosphine oxide (HP=O(OH)2). Note that organic derivatives of phosphonic acids are listed under are ORGANOPHOSPHONATES.

An enzyme that converts ascorbic acid to dehydroascorbic acid. EC 1.10.3.3.

Metabolite of ASCORBIC ACID and the oxidized form of the lactone DEHYDROASCORBIC ACID.

Membrane transport proteins that actively co-transport ASCORBIC ACID and sodium ions across the CELL MEMBRANE. Dietary absorption of VITAMIN C is highly dependent upon this class of transporters and a subset of SODIUM GLUCOSE TRANSPORTERS which transport the oxidized form of vitamin C, DEHYDROASCORBIC ACID.

**Maleates** are organic compounds that contain a carboxylic acid group and a hydroxyl group attached to adjacent carbon atoms, often used as intermediates in the synthesis of pharmaceuticals and other chemicals, or as drugs themselves, such as maleic acid or its salts.

A ubiquitously expressed glucose transporter that is important for constitutive, basal GLUCOSE transport. It is predominately expressed in ENDOTHELIAL CELLS and ERYTHROCYTES at the BLOOD-BRAIN BARRIER and is responsible for GLUCOSE entry into the BRAIN.

A major glucose transporter found in NEURONS.

Tetroses are uncommon sugars (monosaccharides) with four carbon atoms, having an aldehyde functional group at the first carbon atom, and forming ring structures in their cyclic forms, primarily found in complex carbohydrates and certain natural products.

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).

Materials that add an electron to an element or compound, that is, decrease the positiveness of its valence. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)

2-Deoxy-D-arabino-hexose. An antimetabolite of glucose with antiviral activity.

A large group of membrane transport proteins that shuttle MONOSACCHARIDES across CELL MEMBRANES.

A reagent commonly used in biochemical studies as a protective agent to prevent the oxidation of SH (thiol) groups and for reducing disulphides to dithiols.

Inorganic salts of the hypothetical acid, H3Fe(CN)6.

A flavonol widely distributed in plants. It is an antioxidant, like many other phenolic heterocyclic compounds. Glycosylated forms include RUTIN and quercetrin.

A promyelocytic cell line derived from a patient with ACUTE PROMYELOCYTIC LEUKEMIA. HL-60 cells lack specific markers for LYMPHOID CELLS but express surface receptors for FC FRAGMENTS and COMPLEMENT SYSTEM PROTEINS. They also exhibit phagocytic activity and responsiveness to chemotactic stimuli. (From Hay et al., American Type Culture Collection, 7th ed, pp127-8)

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.

A non-metabolizable glucose analogue that is not phosphorylated by hexokinase. 3-O-Methylglucose is used as a marker to assess glucose transport by evaluating its uptake within various cells and organ systems. (J Neurochem 1993;60(4):1498-504)

Drugs that are chemically similar to naturally occurring metabolites, but differ enough to interfere with normal metabolic pathways. (From AMA Drug Evaluations Annual, 1994, p2033)

A tripeptide with many roles in cells. It conjugates to drugs to make them more soluble for excretion, is a cofactor for some enzymes, is involved in protein disulfide bond rearrangement and reduces peroxides.

Methylglucosides are a type of sugar alcohols, specifically methylated glucose derivatives, which are used as sweetening agents, excipients, and solvents in pharmaceutical and cosmetic products due to their low toxicity and good solubility in water.

A salt of lithium that has been used experimentally as an immunomodulator.

The movement of materials across cell membranes and epithelial layers against an electrochemical gradient, requiring the expenditure of metabolic energy.

A XANTHINE OXIDASE inhibitor that decreases URIC ACID production. It also acts as an antimetabolite on some simpler organisms.

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)

A primary source of energy for living organisms. It is naturally occurring and is found in fruits and other parts of plants in its free state. It is used therapeutically in fluid and nutrient replacement.

A human cell line established from a diffuse histiocytic lymphoma (HISTIOCYTIC LYMPHOMA, DIFFUSE) and displaying many monocytic characteristics. It serves as an in vitro model for MONOCYTE and MACROPHAGE differentiation.

Liquid chromatographic techniques which feature high inlet pressures, high sensitivity, and high speed.

The rate dynamics in chemical or physical systems.

Substances intended to be applied to the human body for cleansing, beautifying, promoting attractiveness, or altering the appearance without affecting the body's structure or functions. Included in this definition are skin creams, lotions, perfumes, lipsticks, fingernail polishes, eye and facial makeup preparations, permanent waves, hair colors, toothpastes, and deodorants, as well as any material intended for use as a component of a cosmetic product. (U.S. Food & Drug Administration Center for Food Safety & Applied Nutrition Office of Cosmetics Fact Sheet (web page) Feb 1995)

Works containing information articles on subjects in every field of knowledge, usually arranged in alphabetical order, or a similar work limited to a special field or subject. (From The ALA Glossary of Library and Information Science, 1983)

Strains of mice in which certain GENES of their GENOMES have been disrupted, or "knocked-out". To produce knockouts, using RECOMBINANT DNA technology, the normal DNA sequence of the gene being studied is altered to prevent synthesis of a normal gene product. Cloned cells in which this DNA alteration is successful are then injected into mouse EMBRYOS to produce chimeric mice. The chimeric mice are then bred to yield a strain in which all the cells of the mouse contain the disrupted gene. Knockout mice are used as EXPERIMENTAL ANIMAL MODELS for diseases (DISEASE MODELS, ANIMAL) and to clarify the functions of the genes.

The portion of chromosome material that remains condensed and is transcriptionally inactive during INTERPHASE.

NATIONAL LIBRARY OF MEDICINE service for health professionals and consumers. It links extensive information from the National Institutes of Health and other reviewed sources of information on specific diseases and conditions.

Addition of methyl groups to DNA. DNA methyltransferases (DNA methylases) perform this reaction using S-ADENOSYLMETHIONINE as the methyl group donor.

Information intended for potential users of medical and healthcare services. There is an emphasis on self-care and preventive approaches as well as information for community-wide dissemination and use.

Devices that cover the nose and mouth to maintain aseptic conditions or to administer inhaled anesthetics or other gases. (UMDNS, 1999)