That portion of the electromagnetic spectrum immediately below the visible range and extending into the x-ray frequencies. The longer wavelengths (near-UV or biotic or vital rays) are necessary for the endogenous synthesis of vitamin D and are also called antirachitic rays; the shorter, ionizing wavelengths (far-UV or abiotic or extravital rays) are viricidal, bactericidal, mutagenic, and carcinogenic and are used as disinfectants.

Spectrophotometric techniques by which the absorption or emmision spectra of radiation from atoms are produced and analyzed.

The art or process of comparing photometrically the relative intensities of the light in different parts of the spectrum.

Determination of the spectra of ultraviolet absorption by specific molecules in gases or liquids, for example Cl2, SO2, NO2, CS2, ozone, mercury vapor, and various unsaturated compounds. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)

The use of ultraviolet electromagnetic radiation in the treatment of disease, usually of the skin. This is the part of the sun's spectrum that causes sunburn and tanning. Ultraviolet A, used in PUVA, is closer to visible light and less damaging than Ultraviolet B, which is ionizing.

Spectrophotometry in the infrared region, usually for the purpose of chemical analysis through measurement of absorption spectra associated with rotational and vibrational energy levels of molecules. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)

The effects of ionizing and nonionizing radiation upon living organisms, organs and tissues, and their constituents, and upon physiologic processes. It includes the effect of irradiation on food, drugs, and chemicals.

Photochemotherapy using PSORALENS as the photosensitizing agent and ultraviolet light type A (UVA).

Redness of the skin produced by congestion of the capillaries. This condition may result from a variety of causes.

Chemical or physical agents that protect the skin from sunburn and erythema by absorbing or blocking ultraviolet radiation.

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

Solid dosage forms, of varying weight, size, and shape, which may be molded or compressed, and which contain a medicinal substance in pure or diluted form. (Dorland, 28th ed)

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.

Microscopy in which the image is formed by ultraviolet radiation and is displayed and recorded by means of photographic film.

The rate dynamics in chemical or physical systems.

The development and use of techniques and equipment to study or perform chemical reactions, with small quantities of materials, frequently less than a milligram or a milliliter.

The visually perceived property of objects created by absorption or reflection of specific wavelengths of light.

Irradiation directly from the sun.

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)

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).

An allotropic form of carbon that is used in pencils, as a lubricant, and in matches and explosives. It is obtained by mining and its dust can cause lung irritation.

Determination, by measurement or comparison with a standard, of the correct value of each scale reading on a meter or other measuring instrument; or determination of the settings of a control device that correspond to particular values of voltage, current, frequency or other output.

The relationship between the dose of administered radiation and the response of the organism or tissue to the radiation.

A compound formed by the combination of hemoglobin and oxygen. It is a complex in which the oxygen is bound directly to the iron without causing a change from the ferrous to the ferric state.

A series of steps taken in order to conduct research.

A heavy metal trace element with the atomic symbol Cu, atomic number 29, and atomic weight 63.55.

Mutant strains of mice that produce little or no hair.

Substances used for the detection, identification, analysis, etc. of chemical, biological, or pathologic processes or conditions. Indicators are substances that change in physical appearance, e.g., color, at or approaching the endpoint of a chemical titration, e.g., on the passage between acidity and alkalinity. Reagents are substances used for the detection or determination of another substance by chemical or microscopical means, especially analysis. Types of reagents are precipitants, solvents, oxidizers, reducers, fluxes, and colorimetric reagents. (From Grant & Hackh's Chemical Dictionary, 5th ed, p301, p499)

Measurement of the intensity and quality of fluorescence.

The outer covering of the body that protects it from the environment. It is composed of the DERMIS and the EPIDERMIS.

Chemicals and substances that impart color including soluble dyes and insoluble pigments. They are used in INKS; PAINTS; and as INDICATORS AND REAGENTS.

Any technique by which an unknown color is evaluated in terms of standard colors. The technique may be visual, photoelectric, or indirect by means of spectrophotometry. It is used in chemistry and physics. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)

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)

A metallic element that has the atomic number 13, atomic symbol Al, and atomic weight 26.98.

A tricarbocyanine dye that is used diagnostically in liver function tests and to determine blood volume and cardiac output.

Chromatography on thin layers of adsorbents rather than in columns. The adsorbent can be alumina, silica gel, silicates, charcoals, or cellulose. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)

A soft, grayish metal with poisonous salts; atomic number 82, atomic weight 207.19, symbol Pb. (Dorland, 28th)

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)

A bile pigment that is a degradation product of HEME.

Dimers found in DNA chains damaged by ULTRAVIOLET RAYS. They consist of two adjacent PYRIMIDINE NUCLEOTIDES, usually THYMINE nucleotides, in which the pyrimidine residues are covalently joined by a cyclobutane ring. These dimers block DNA REPLICATION.

A subdiscipline of genetics that studies RADIATION EFFECTS on the components and processes of biological inheritance.

An injury to the skin causing erythema, tenderness, and sometimes blistering and resulting from excessive exposure to the sun. The reaction is produced by the ultraviolet radiation in sunlight.

Insoluble polymers of TYROSINE derivatives found in and causing darkness in skin (SKIN PIGMENTATION), hair, and feathers providing protection against SUNBURN induced by SUNLIGHT. CAROTENES contribute yellow and red coloration.

Coloration of the skin.

Method for determining the circulating blood volume by introducing a known quantity of foreign substance into the blood and determining its concentration some minutes later when thorough mixing has occurred. From these two values the blood volume can be calculated by dividing the quantity of injected material by its concentration in the blood at the time of uniform mixing. Generally expressed as cubic centimeters or liters per kilogram of body weight.

The measurement of the density of a material by measuring the amount of light or radiation passing through (or absorbed by) the material.

A naturally occurring furocoumarin compound found in several species of plants, including Psoralea corylifolia. It is a photoactive substance that forms DNA ADDUCTS in the presence of ultraviolet A irradiation.

The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.

Inorganic compounds that contain magnesium as an integral part of the molecule.

Method of analyzing chemicals using automation.

The analysis of a chemical substance by inserting a sample into a carrier stream of reagent using a sample injection valve that propels the sample downstream where mixing occurs in a coiled tube, then passes into a flow-through detector and a recorder or other data handling device.

Tumors, cancer or other neoplasms produced by exposure to ionizing or non-ionizing radiation.

Elements of limited time intervals, contributing to particular results or situations.

A basic science concerned with the composition, structure, and properties of matter; and the reactions that occur between substances and the associated energy exchange.

Tumors or cancer of the SKIN.

A silver metallic element that exists as a liquid at room temperature. It has the atomic symbol Hg (from hydrargyrum, liquid silver), atomic number 80, and atomic weight 200.59. Mercury is used in many industrial applications and its salts have been employed therapeutically as purgatives, antisyphilitics, disinfectants, and astringents. It can be absorbed through the skin and mucous membranes which leads to MERCURY POISONING. Because of its toxicity, the clinical use of mercury and mercurials is diminishing.

Dithionite. The dithionous acid ion and its salts.

A metallic element that has the atomic symbol Mg, atomic number 12, and atomic weight 24.31. It is important for the activity of many enzymes, especially those involved in OXIDATIVE PHOSPHORYLATION.

The composition, conformation, and properties of atoms and molecules, and their reaction and interaction processes.

Inorganic compounds that contain potassium as an integral part of the molecule.

A trace element that plays a role in glucose metabolism. It has the atomic symbol Cr, atomic number 24, and atomic weight 52. According to the Fourth Annual Report on Carcinogens (NTP85-002,1985), chromium and some of its compounds have been listed as known carcinogens.

An inorganic compound that is used as a source of iodine in thyrotoxic crisis and in the preparation of thyrotoxic patients for thyroidectomy. (From Dorland, 27th ed)

Metals with high specific gravity, typically larger than 5. They have complex spectra, form colored salts and double salts, have a low electrode potential, are mainly amphoteric, yield weak bases and weak acids, and are oxidizing or reducing agents (From Grant & Hackh's Chemical Dictionary, 5th ed)

The chemical and physical integrity of a pharmaceutical product.

That portion of the electromagnetic spectrum in the visible, ultraviolet, and infrared range.

The statistical reproducibility of measurements (often in a clinical context), including the testing of instrumentation or techniques to obtain reproducible results. The concept includes reproducibility of physiological measurements, which may be used to develop rules to assess probability or prognosis, or response to a stimulus; reproducibility of occurrence of a condition; and reproducibility of experimental results.

The reconstruction of a continuous two-stranded DNA molecule without mismatch from a molecule which contained damaged regions. The major repair mechanisms are excision repair, in which defective regions in one strand are excised and resynthesized using the complementary base pairing information in the intact strand; photoreactivation repair, in which the lethal and mutagenic effects of ultraviolet light are eliminated; and post-replication repair, in which the primary lesions are not repaired, but the gaps in one daughter duplex are filled in by incorporation of portions of the other (undamaged) daughter duplex. Excision repair and post-replication repair are sometimes referred to as "dark repair" because they do not require light.

A strong corrosive acid that is commonly used as a laboratory reagent. It is formed by dissolving hydrogen chloride in water. GASTRIC ACID is the hydrochloric acid component of GASTRIC JUICE.

Tapping fluid from the subarachnoid space in the lumbar region, usually between the third and fourth lumbar vertebrae.

Inorganic or organic salts and esters of boric acid.

A plant genus of the family ASTERACEAE. Other plants called broom include CYTISUS; SPARTIUM; and BROMUS.

The homogeneous mixtures formed by the mixing of a solid, liquid, or gaseous substance (solute) with a liquid (the solvent), from which the dissolved substances can be recovered by physical processes. (From Grant & Hackh's Chemical Dictionary, 5th ed)

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.

Abnormal responses to sunlight or artificial light due to extreme reactivity of light-absorbing molecules in tissues. It refers almost exclusively to skin photosensitivity, including sunburn, reactions due to repeated prolonged exposure in the absence of photosensitizing factors, and reactions requiring photosensitizing factors such as photosensitizing agents and certain diseases. With restricted reference to skin tissue, it does not include photosensitivity of the eye to light, as in photophobia or photosensitive epilepsy.

The process of aging due to changes in the structure and elasticity of the skin over time. It may be a part of physiological aging or it may be due to the effects of ultraviolet radiation, usually through exposure to sunlight.

An element with atomic symbol Cd, atomic number 48, and atomic weight 114. It is a metal and ingestion will lead to CADMIUM POISONING.

Epidermal cells which synthesize keratin and undergo characteristic changes as they move upward from the basal layers of the epidermis to the cornified (horny) layer of the skin. Successive stages of differentiation of the keratinocytes forming the epidermal layers are basal cell, spinous or prickle cell, and the granular cell.

A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).

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.

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.

Proteins in the cerebrospinal fluid, normally albumin and globulin present in the ratio of 8 to 1. Increases in protein levels are of diagnostic value in neurological diseases. (Brain and Bannister's Clinical Neurology, 7th ed, p221)

A filament-like structure consisting of a shaft which projects to the surface of the SKIN from a root which is softer than the shaft and lodges in the cavity of a HAIR FOLLICLE. It is found on most surfaces of the body.

A clear, odorless, tasteless liquid that is essential for most animal and plant life and is an excellent solvent for many substances. The chemical formula is hydrogen oxide (H2O). (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)

Tantalum. A rare metallic element, atomic number 73, atomic weight 180.948, symbol Ta. It is a noncorrosive and malleable metal that has been used for plates or disks to replace cranial defects, for wire sutures, and for making prosthetic devices. (Dorland, 28th ed)

Inorganic or organic compounds containing trivalent iron.

A trace element with the atomic symbol Ni, atomic number 28, and atomic weight 58.69. It is a cofactor of the enzyme UREASE.

A naturally occurring furocoumarin, found in PSORALEA. After photoactivation with UV radiation, it binds DNA via single and double-stranded cross-linking.

A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.

4-Imidazoleacrylic acid.

Chemical compounds which pollute the water of rivers, streams, lakes, the sea, reservoirs, or other bodies of water.

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)

Fractionation of a vaporized sample as a consequence of partition between a mobile gaseous phase and a stationary phase held in a column. Two types are gas-solid chromatography, where the fixed phase is a solid, and gas-liquid, in which the stationary phase is a nonvolatile liquid supported on an inert solid matrix.

Concentration or quantity that is derived from the smallest measure that can be detected with reasonable certainty for a given analytical procedure.

Red blood cells. Mature erythrocytes are non-nucleated, biconcave disks containing HEMOGLOBIN whose function is to transport OXYGEN.

A change from planar to elliptic polarization when an initially plane-polarized light wave traverses an optically active medium. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)

Chemical analysis based on the phenomenon whereby light, passing through a medium with dispersed particles of a different refractive index from that of the medium, is attenuated in intensity by scattering. In turbidimetry, the intensity of light transmitted through the medium, the unscattered light, is measured. In nephelometry, the intensity of the scattered light is measured, usually, but not necessarily, at right angles to the incident light beam.

A type of acute or chronic skin reaction in which sensitivity is manifested by reactivity to materials or substances coming in contact with the skin. It may involve allergic or non-allergic mechanisms.

Injuries to DNA that introduce deviations from its normal, intact structure and which may, if left unrepaired, result in a MUTATION or a block of DNA REPLICATION. These deviations may be caused by physical or chemical agents and occur by natural or unnatural, introduced circumstances. They include the introduction of illegitimate bases during replication or by deamination or other modification of bases; the loss of a base from the DNA backbone leaving an abasic site; single-strand breaks; double strand breaks; and intrastrand (PYRIMIDINE DIMERS) or interstrand crosslinking. Damage can often be repaired (DNA REPAIR). If the damage is extensive, it can induce APOPTOSIS.

An analytical method used in determining the identity of a chemical based on its mass using mass analyzers/mass spectrometers.

Relating to the size of solids.

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.

The physical or physiological processes by which substances, tissue, cells, etc. take up or take in other substances or energy.

Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.

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.

Derivatives of the dimethylisoalloxazine (7,8-dimethylbenzo[g]pteridine-2,4(3H,10H)-dione) skeleton. Flavin derivatives serve an electron transfer function as ENZYME COFACTORS in FLAVOPROTEINS.

A basic element found in nearly all organized tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.

Naturally occurring or synthetic substances that inhibit or retard the oxidation of a substance to which it is added. They counteract the harmful and damaging effects of oxidation in animal tissues.

Concentrated pharmaceutical preparations of plants obtained by removing active constituents with a suitable solvent, which is evaporated away, and adjusting the residue to a prescribed standard.

Platinum. A heavy, soft, whitish metal, resembling tin, atomic number 78, atomic weight 195.09, symbol Pt. (From Dorland, 28th ed) It is used in manufacturing equipment for laboratory and industrial use. It occurs as a black powder (platinum black) and as a spongy substance (spongy platinum) and may have been known in Pliny's time as "alutiae".

A multisubunit enzyme complex containing CYTOCHROME A GROUP; CYTOCHROME A3; two copper atoms; and 13 different protein subunits. It is the terminal oxidase complex of the RESPIRATORY CHAIN and collects electrons that are transferred from the reduced CYTOCHROME C GROUP and donates them to molecular OXYGEN, which is then reduced to water. The redox reaction is simultaneously coupled to the transport of PROTONS across the inner mitochondrial membrane.

A chemical element having an atomic weight of 106.4, atomic number of 46, and the symbol Pd. It is a white, ductile metal resembling platinum, and following it in abundance and importance of applications. It is used in dentistry in the form of gold, silver, and copper alloys.

A rare, pigmentary, and atrophic autosomal recessive disease. It is manifested as an extreme photosensitivity to ULTRAVIOLET RAYS as the result of a deficiency in the enzyme that permits excisional repair of ultraviolet-damaged DNA.

Drugs intended for human or veterinary use, presented in their finished dosage form. Included here are materials used in the preparation and/or formulation of the finished dosage form.

Theoretical representations that simulate the behavior or activity of chemical processes or phenomena; includes the use of mathematical equations, computers, and other electronic equipment.

Carbon monoxide (CO). A poisonous colorless, odorless, tasteless gas. It combines with hemoglobin to form carboxyhemoglobin, which has no oxygen carrying capacity. The resultant oxygen deprivation causes headache, dizziness, decreased pulse and respiratory rates, unconsciousness, and death. (From Merck Index, 11th ed)

Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.

Inorganic or organic oxy acids of sulfur which contain the RSO2(OH) radical.

The range or frequency distribution of a measurement in a population (of organisms, organs or things) that has not been selected for the presence of disease or abnormality.

The property of emitting radiation while being irradiated. The radiation emitted is usually of longer wavelength than that incident or absorbed, e.g., a substance can be irradiated with invisible radiation and emit visible light. X-ray fluorescence is used in diagnosis.

Liquids that dissolve other substances (solutes), generally solids, without any change in chemical composition, as, water containing sugar. (Grant & Hackh's Chemical Dictionary, 5th ed)

The location of the atoms, groups or ions relative to one another in a molecule, as well as the number, type and location of covalent bonds.

The external, nonvascular layer of the skin. It is made up, from within outward, of five layers of EPITHELIUM: (1) basal layer (stratum basale epidermidis); (2) spinous layer (stratum spinosum epidermidis); (3) granular layer (stratum granulosum epidermidis); (4) clear layer (stratum lucidum epidermidis); and (5) horny layer (stratum corneum epidermidis).

A compound consisting of dark green crystals or crystalline powder, having a bronze-like luster. Solutions in water or alcohol have a deep blue color. Methylene blue is used as a bacteriologic stain and as an indicator. It inhibits GUANYLATE CYCLASE, and has been used to treat cyanide poisoning and to lower levels of METHEMOGLOBIN.

The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.

Bleeding into the intracranial or spinal SUBARACHNOID SPACE, most resulting from INTRACRANIAL ANEURYSM rupture. It can occur after traumatic injuries (SUBARACHNOID HEMORRHAGE, TRAUMATIC). Clinical features include HEADACHE; NAUSEA; VOMITING, nuchal rigidity, variable neurological deficits and reduced mental status.

A system for verifying and maintaining a desired level of quality in a product or process by careful planning, use of proper equipment, continued inspection, and corrective action as required. (Random House Unabridged Dictionary, 2d ed)

An element with the atomic symbol Se, atomic number 34, and atomic weight 78.96. It is an essential micronutrient for mammals and other animals but is toxic in large amounts. Selenium protects intracellular structures against oxidative damage. It is an essential component of GLUTATHIONE PEROXIDASE.

A conjugated protein which is the oxygen-transporting pigment of muscle. It is made up of one globin polypeptide chain and one heme group.

A basis of value established for the measure of quantity, weight, extent or quality, e.g. weight standards, standard solutions, methods, techniques, and procedures used in diagnosis and therapy.

Studies determining the effectiveness or value of processes, personnel, and equipment, or the material on conducting such studies. For drugs and devices, CLINICAL TRIALS AS TOPIC; DRUG EVALUATION; and DRUG EVALUATION, PRECLINICAL are available.

A trace element that is a component of vitamin B12. It has the atomic symbol Co, atomic number 27, and atomic weight 58.93. It is used in nuclear weapons, alloys, and pigments. Deficiency in animals leads to anemia; its excess in humans can lead to erythrocytosis.

A spectroscopic technique in which a range of wavelengths is presented simultaneously with an interferometer and the spectrum is mathematically derived from the pattern thus obtained.

Hemeproteins whose characteristic mode of action involves transfer of reducing equivalents which are associated with a reversible change in oxidation state of the prosthetic group. Formally, this redox change involves a single-electron, reversible equilibrium between the Fe(II) and Fe(III) states of the central iron atom (From Enzyme Nomenclature, 1992, p539). The various cytochrome subclasses are organized by the type of HEME and by the wavelength range of their reduced alpha-absorption bands.

The separation of particles from a suspension by passage through a filter with very fine pores. In ultrafiltration the separation is accomplished by convective transport; in DIALYSIS separation relies instead upon differential diffusion. Ultrafiltration occurs naturally and is a laboratory procedure. Artificial ultrafiltration of the blood is referred to as HEMOFILTRATION or HEMODIAFILTRATION (if combined with HEMODIALYSIS).

The monitoring of the level of toxins, chemical pollutants, microbial contaminants, or other harmful substances in the environment (soil, air, and water), workplace, or in the bodies of people and animals present in that environment.

Spectroscopic method of measuring the magnetic moment of elementary particles such as atomic nuclei, protons or electrons. It is employed in clinical applications such as NMR Tomography (MAGNETIC RESONANCE IMAGING).

Inorganic salts of HYDROGEN CYANIDE containing the -CN radical. The concept also includes isocyanides. It is distinguished from NITRILES, which denotes organic compounds containing the -CN radical.

Mammalian pigment cells that produce MELANINS, pigments found mainly in the EPIDERMIS, but also in the eyes and the hair, by a process called melanogenesis. Coloration can be altered by the number of melanocytes or the amount of pigment produced and stored in the organelles called MELANOSOMES. The large non-mammalian melanin-containing cells are called MELANOPHORES.

A colorless, flammable liquid used in the manufacture of FORMALDEHYDE and ACETIC ACID, in chemical synthesis, antifreeze, and as a solvent. Ingestion of methanol is toxic and may cause blindness.

Presence of warmth or heat or a temperature notably higher than an accustomed norm.

A thiazide diuretic often considered the prototypical member of this class. It reduces the reabsorption of electrolytes from the renal tubules. This results in increased excretion of water and electrolytes, including sodium, potassium, chloride, and magnesium. It is used in the treatment of several disorders including edema, hypertension, diabetes insipidus, and hypoparathyroidism.

Stable elementary particles having the smallest known negative charge, present in all elements; also called negatrons. Positively charged electrons are called positrons. The numbers, energies and arrangement of electrons around atomic nuclei determine the chemical identities of elements. Beams of electrons are called CATHODE RAYS.

A metallic element with the atomic symbol Mo, atomic number 42, and atomic weight 95.94. It is an essential trace element, being a component of the enzymes xanthine oxidase, aldehyde oxidase, and nitrate reductase. (From Dorland, 27th ed)

The ability of a substance to be dissolved, i.e. to form a solution with another substance. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)

Chinese herbal or plant extracts which are used as drugs to treat diseases or promote general well-being. The concept does not include synthesized compounds manufactured in China.

The process by which ELECTRONS are transported from a reduced substrate to molecular OXYGEN. (From Bennington, Saunders Dictionary and Encyclopedia of Laboratory Medicine and Technology, 1984, p270)

The application of scientific knowledge or technology to pharmacy and the pharmaceutical industry. It includes methods, techniques, and instrumentation in the manufacture, preparation, compounding, dispensing, packaging, and storing of drugs and other preparations used in diagnostic and determinative procedures, and in the treatment of patients.

The species Oryctolagus cuniculus, in the family Leporidae, order LAGOMORPHA. Rabbits are born in burrows, furless, and with eyes and ears closed. In contrast with HARES, rabbits have 22 chromosome pairs.

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.

Inorganic or organic compounds that contain divalent iron.

The facilitation of a chemical reaction by material (catalyst) that is not consumed by the reaction.

Transparent, tasteless crystals found in nature as agate, amethyst, chalcedony, cristobalite, flint, sand, QUARTZ, and tridymite. The compound is insoluble in water or acids except hydrofluoric acid.

A noninvasive technique that uses the differential absorption properties of hemoglobin and myoglobin to evaluate tissue oxygenation and indirectly can measure regional hemodynamics and blood flow. Near-infrared light (NIR) can propagate through tissues and at particular wavelengths is differentially absorbed by oxygenated vs. deoxygenated forms of hemoglobin and myoglobin. Illumination of intact tissue with NIR allows qualitative assessment of changes in the tissue concentration of these molecules. The analysis is also used to determine body composition.

A chemical system that functions to control the levels of specific ions in solution. When the level of hydrogen ion in solution is controlled the system is called a pH buffer.

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).

The rate at which oxygen is used by a tissue; microliters of oxygen STPD used per milligram of tissue per hour; the rate at which oxygen enters the blood from alveolar gas, equal in the steady state to the consumption of oxygen by tissue metabolism throughout the body. (Stedman, 25th ed, p346)

The general name for a group of fat-soluble pigments found in green, yellow, and leafy vegetables, and yellow fruits. They are aliphatic hydrocarbons consisting of a polyisoprene backbone.

The exposure to potentially harmful chemical, physical, or biological agents in the environment or to environmental factors that may include ionizing radiation, pathogenic organisms, or toxic chemicals.

A rigorously mathematical analysis of energy relationships (heat, work, temperature, and equilibrium). It describes systems whose states are determined by thermal parameters, such as temperature, in addition to mechanical and electromagnetic parameters. (From Hawley's Condensed Chemical Dictionary, 12th ed)

Benzene derivatives that include one or more hydroxyl groups attached to the ring structure.

An oxidoreductase that catalyzes the conversion of HYDROGEN PEROXIDE to water and oxygen. It is present in many animal cells. A deficiency of this enzyme results in ACATALASIA.

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.

The diversion of RADIATION (thermal, electromagnetic, or nuclear) from its original path as a result of interactions or collisions with atoms, molecules, or larger particles in the atmosphere or other media. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)

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.

The products of chemical reactions that result in the addition of extraneous chemical groups to DNA.

A shiny gray element with atomic symbol As, atomic number 33, and atomic weight 75. It occurs throughout the universe, mostly in the form of metallic arsenides. Most forms are toxic. According to the Fourth Annual Report on Carcinogens (NTP 85-002, 1985), arsenic and certain arsenic compounds have been listed as known carcinogens. (From Merck Index, 11th ed)

Volume of circulating BLOOD. It is the sum of the PLASMA VOLUME and ERYTHROCYTE VOLUME.

The study of chemical changes resulting from electrical action and electrical activity resulting from chemical changes.

A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.

Binary classification measures to assess test results. Sensitivity or recall rate is the proportion of true positives. Specificity is the probability of correctly determining the absence of a condition. (From Last, Dictionary of Epidemiology, 2d ed)

The parts of a macromolecule that directly participate in its specific combination with another molecule.

The color-furnishing portion of hemoglobin. It is found free in tissues and as the prosthetic group in many hemeproteins.

A nonimmunologic, chemically induced type of photosensitivity producing a sometimes vesiculating dermatitis. It results in hyperpigmentation and desquamation of the light-exposed areas of the skin.

Nicotinamide adenine dinucleotide phosphate. A coenzyme composed of ribosylnicotinamide 5'-phosphate (NMN) coupled by pyrophosphate linkage to the 5'-phosphate adenosine 2',5'-bisphosphate. It serves as an electron carrier in a number of reactions, being alternately oxidized (NADP+) and reduced (NADPH). (Dorland, 27th ed)

The deductive study of shape, quantity, and dependence. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)

Chemical bond cleavage reactions resulting from absorption of radiant energy.

Chemistry dealing with the composition and preparation of agents having PHARMACOLOGIC ACTIONS or diagnostic use.

Particles consisting of aggregates of molecules held loosely together by secondary bonds. The surface of micelles are usually comprised of amphiphatic compounds that are oriented in a way that minimizes the energy of interaction between the micelle and its environment. Liquids that contain large numbers of suspended micelles are referred to as EMULSIONS.

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)

Electropositive chemical elements characterized by ductility, malleability, luster, and conductance of heat and electricity. They can replace the hydrogen of an acid and form bases with hydroxyl radicals. (Grant & Hackh's Chemical Dictionary, 5th ed)

Differential thermal analysis in which the sample compartment of the apparatus is a differential calorimeter, allowing an exact measure of the heat of transition independent of the specific heat, thermal conductivity, and other variables of the sample.

Exposing oneself to SUNLIGHT or ULTRAVIOLET RAYS.

An oxidoreductase that catalyzes the reaction between superoxide anions and hydrogen to yield molecular oxygen and hydrogen peroxide. The enzyme protects the cell against dangerous levels of superoxide. EC 1.15.1.1.

Established cell cultures that have the potential to propagate indefinitely.

The testing of materials and devices, especially those used for PROSTHESES AND IMPLANTS; SUTURES; TISSUE ADHESIVES; etc., for hardness, strength, durability, safety, efficacy, and biocompatibility.

The dialdehyde of malonic acid.

A group of cytochromes with covalent thioether linkages between either or both of the vinyl side chains of protoheme and the protein. (Enzyme Nomenclature, 1992, p539)

Genetically identical individuals developed from brother and sister matings which have been carried out for twenty or more generations or by parent x offspring matings carried out with certain restrictions. This also includes animals with a long history of closed colony breeding.

A common genetically determined, chronic, inflammatory skin disease characterized by rounded erythematous, dry, scaling patches. The lesions have a predilection for nails, scalp, genitalia, extensor surfaces, and the lumbosacral region. Accelerated epidermopoiesis is considered to be the fundamental pathologic feature in psoriasis.

Compounds containing the -SH radical.

Large, hoofed mammals of the family EQUIDAE. Horses are active day and night with most of the day spent seeking and consuming food. Feeding peaks occur in the early morning and late afternoon, and there are several daily periods of rest.

A condensation product of riboflavin and adenosine diphosphate. The coenzyme of various aerobic dehydrogenases, e.g., D-amino acid oxidase and L-amino acid oxidase. (Lehninger, Principles of Biochemistry, 1982, p972)

Chemicals that bind to and remove ions from solutions. Many chelating agents function through the formation of COORDINATION COMPLEXES with METALS.

The process of cleaving a chemical compound by the addition of a molecule of water.

Polymers of ETHYLENE OXIDE and water, and their ethers. They vary in consistency from liquid to solid depending on the molecular weight indicated by a number following the name. They are used as SURFACTANTS, dispersing agents, solvents, ointment and suppository bases, vehicles, and tablet excipients. Some specific groups are NONOXYNOLS, OCTOXYNOLS, and POLOXAMERS.

A microanalytical technique combining mass spectrometry and gas chromatography for the qualitative as well as quantitative determinations of compounds.