The administration of drugs by the respiratory route. It includes insufflation into the respiratory tract.

The exposure to potentially harmful chemical, physical, or biological agents by inhaling them.

Pulmonary injury following the breathing in of toxic smoke from burning materials such as plastics, synthetics, building materials, etc. This injury is the most frequent cause of death in burn patients.

Burns of the respiratory tract caused by heat or inhaled chemicals.

The act of BREATHING in.

The giving of drugs, chemicals, or other substances by mouth.

Colloids with a gaseous dispersing phase and either liquid (fog) or solid (smoke) dispersed phase; used in fumigation or in inhalation therapy; may contain propellant agents.

Either of the pair of organs occupying the cavity of the thorax that effect the aeration of the blood.

Gases or volatile liquids that vary in the rate at which they induce anesthesia; potency; the degree of circulation, respiratory, or neuromuscular depression they produce; and analgesic effects. Inhalation anesthetics have advantages over intravenous agents in that the depth of anesthesia can be changed rapidly by altering the inhaled concentration. Because of their rapid elimination, any postoperative respiratory depression is of relatively short duration. (From AMA Drug Evaluations Annual, 1994, p173)

The relationship between the dose of an administered drug and the response of the organism to the drug.

Time schedule for administration of a drug in order to achieve optimum effectiveness and convenience.

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

Anesthesia caused by the breathing of anesthetic gases or vapors or by insufflating anesthetic gases or vapors into the respiratory tract.

Injections made into a vein for therapeutic or experimental purposes.

Substances made up of an aggregation of small particles, as that obtained by grinding or trituration of a solid drug. In pharmacy it is a form in which substances are administered. (From Dorland, 28th ed)

A strain of albino rat used widely for experimental purposes because of its calmness and ease of handling. It was developed by the Sprague-Dawley Animal Company.

The various ways of administering a drug or other chemical to a site in a patient or animal from where the chemical is absorbed into the blood and delivered to the target tissue.

An agency of the PUBLIC HEALTH SERVICE concerned with the overall planning, promoting, and administering of programs pertaining to maintaining standards of quality of foods, drugs, therapeutic devices, etc.

Delivery of medications through the nasal mucosa.

Naturally occurring or experimentally induced animal diseases with pathological processes sufficiently similar to those of human diseases. They are used as study models for human diseases.

Tests involving inhalation of allergens (nebulized or in dust form), nebulized pharmacologically active solutions (e.g., histamine, methacholine), or control solutions, followed by assessment of respiratory function. These tests are used in the diagnosis of asthma.

A strain of albino rat developed at the Wistar Institute that has spread widely at other institutions. This has markedly diluted the original strain.

A form of bronchial disorder with three distinct components: airway hyper-responsiveness (RESPIRATORY HYPERSENSITIVITY), airway INFLAMMATION, and intermittent AIRWAY OBSTRUCTION. It is characterized by spasmodic contraction of airway smooth muscle, WHEEZING, and dyspnea (DYSPNEA, PAROXYSMAL).

Agents that cause an increase in the expansion of a bronchus or bronchial tubes.

F344 rats are an inbred strain of albino laboratory rats (Rattus norvegicus) that have been widely used in biomedical research due to their consistent and reliable genetic background, which facilitates the study of disease mechanisms and therapeutic interventions.

A short-acting beta-2 adrenergic agonist that is primarily used as a bronchodilator agent to treat ASTHMA. Albuterol is prepared as a racemic mixture of R(-) and S(+) stereoisomers. The stereospecific preparation of R(-) isomer of albuterol is referred to as levalbuterol.

Forceful administration into the peritoneal cavity of liquid medication, nutrient, or other fluid through a hollow needle piercing the abdominal wall.

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.

Experimental devices used in inhalation studies in which a person or animal is either partially or completely immersed in a chemically controlled atmosphere.

Inbred C57BL mice are a strain of laboratory mice that have been produced by many generations of brother-sister matings, resulting in a high degree of genetic uniformity and homozygosity, making them widely used for biomedical research, including studies on genetics, immunology, cancer, and neuroscience.

Relating to the size of solids.

Washing liquid obtained from irrigation of the lung, including the BRONCHI and the PULMONARY ALVEOLI. It is generally used to assess biochemical, inflammatory, or infection status of the lung.

Studies comparing two or more treatments or interventions in which the subjects or patients, upon completion of the course of one treatment, are switched to another. In the case of two treatments, A and B, half the subjects are randomly allocated to receive these in the order A, B and half to receive them in the order B, A. A criticism of this design is that effects of the first treatment may carry over into the period when the second is given. (Last, A Dictionary of Epidemiology, 2d ed)

A method of studying a drug or procedure in which both the subjects and investigators are kept unaware of who is actually getting which specific treatment.

A device that delivers medication to the lungs in the form of a dry powder.

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

Forceful administration under the skin of liquid medication, nutrient, or other fluid through a hollow needle piercing the skin.

Air pollutants found in the work area. They are usually produced by the specific nature of the occupation.

A quaternary ammonium parasympathomimetic agent with the muscarinic actions of ACETYLCHOLINE. It is hydrolyzed by ACETYLCHOLINESTERASE at a considerably slower rate than ACETYLCHOLINE and is more resistant to hydrolysis by nonspecific CHOLINESTERASES so that its actions are more prolonged. It is used as a parasympathomimetic bronchoconstrictor agent and as a diagnostic aid for bronchial asthma. (From Martindale, The Extra Pharmacopoeia, 30th ed, p1116)

Unstable isotopes of xenon that decay or disintegrate emitting radiation. Xe atoms with atomic weights 121-123, 125, 127, 133, 135, 137-145 are radioactive xenon isotopes.

A variety of devices used in conjunction with METERED DOSE INHALERS. Their purpose is to hold the released medication for inhalation and make it easy for the patients to inhale the metered dose of medication into their lungs.

Measure of the maximum amount of air that can be expelled in a given number of seconds during a FORCED VITAL CAPACITY determination . It is usually given as FEV followed by a subscript indicating the number of seconds over which the measurement is made, although it is sometimes given as a percentage of forced vital capacity.

Narrowing of the caliber of the BRONCHI, physiologically or as a result of pharmacological intervention.

Physiologically, the opposition to flow of air caused by the forces of friction. As a part of pulmonary function testing, it is the ratio of driving pressure to the rate of air flow.

The time it takes for a substance (drug, radioactive nuclide, or other) to lose half of its pharmacologic, physiologic, or radiologic activity.

The act of breathing with the LUNGS, consisting of INHALATION, or the taking into the lungs of the ambient air, and of EXHALATION, or the expelling of the modified air which contains more CARBON DIOXIDE than the air taken in (Blakiston's Gould Medical Dictionary, 4th ed.). This does not include tissue respiration (= OXYGEN CONSUMPTION) or cell respiration (= CELL RESPIRATION).

Injuries to tissues caused by contact with heat, steam, chemicals (BURNS, CHEMICAL), electricity (BURNS, ELECTRIC), or the like.

The domestic dog, Canis familiaris, comprising about 400 breeds, of the carnivore family CANIDAE. They are worldwide in distribution and live in association with people. (Walker's Mammals of the World, 5th ed, p1065)

The application of drug preparations to the surfaces of the body, especially the skin (ADMINISTRATION, CUTANEOUS) or mucous membranes. This method of treatment is used to avoid systemic side effects when high doses are required at a localized area or as an alternative systemic administration route, to avoid hepatic processing for example.

Nitrogen oxide (N2O). A colorless, odorless gas that is used as an anesthetic and analgesic. High concentrations cause a narcotic effect and may replace oxygen, causing death by asphyxia. It is also used as a food aerosol in the preparation of whipping cream.

The larger air passages of the lungs arising from the terminal bifurcation of the TRACHEA. They include the largest two primary bronchi which branch out into secondary bronchi, and tertiary bronchi which extend into BRONCHIOLES and PULMONARY ALVEOLI.

Accumulation of a drug or chemical substance in various organs (including those not relevant to its pharmacologic or therapeutic action). This distribution depends on the blood flow or perfusion rate of the organ, the ability of the drug to penetrate organ membranes, tissue specificity, protein binding. The distribution is usually expressed as tissue to plasma ratios.

Inbred BALB/c mice are a strain of laboratory mice that have been selectively bred to be genetically identical to each other, making them useful for scientific research and experiments due to their consistent genetic background and predictable responses to various stimuli or treatments.

Tendency of the smooth muscle of the tracheobronchial tree to contract more intensely in response to a given stimulus than it does in the response seen in normal individuals. This condition is present in virtually all symptomatic patients with asthma. The most prominent manifestation of this smooth muscle contraction is a decrease in airway caliber that can be readily measured in the pulmonary function laboratory.

The long-term (minutes to hours) administration of a fluid into the vein through venipuncture, either by letting the fluid flow by gravity or by pumping it.

The insertion of drugs into the rectum, usually for confused or incompetent patients, like children, infants, and the very old or comatose.

A colorless, odorless gas that can be formed by the body and is necessary for the respiration cycle of plants and animals.

Forceful administration into a muscle of liquid medication, nutrient, or other fluid through a hollow needle piercing the muscle and any tissue covering it.

A small aerosol canister used to release a calibrated amount of medication for inhalation.

A statistical means of summarizing information from a series of measurements on one individual. It is frequently used in clinical pharmacology where the AUC from serum levels can be interpreted as the total uptake of whatever has been administered. As a plot of the concentration of a drug against time, after a single dose of medicine, producing a standard shape curve, it is a means of comparing the bioavailability of the same drug made by different companies. (From Winslade, Dictionary of Clinical Research, 1992)

Any substance in the air which could, if present in high enough concentration, harm humans, animals, vegetation or material. Substances include GASES; PARTICULATE MATTER; and volatile ORGANIC CHEMICALS.

Carboxyhemoglobin is a form of hemoglobin in which the heme group is chemically bonded to carbon monoxide, reducing its ability to transport oxygen and leading to toxic effects when present in high concentrations.

Measurement of the various processes involved in the act of respiration: inspiration, expiration, oxygen and carbon dioxide exchange, lung volume and compliance, etc.

'Smoke' is a complex mixture of gases, fine particles, and volatile compounds, generally produced by combustion of organic substances, which can contain harmful chemicals known to have adverse health effects.

The action of a drug that may affect the activity, metabolism, or toxicity of another drug.

Evaluation undertaken to assess the results or consequences of management and procedures used in combating disease in order to determine the efficacy, effectiveness, safety, and practicability of these interventions in individual cases or series.

The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM.

The tubular and cavernous organs and structures, by means of which pulmonary ventilation and gas exchange between ambient air and the blood are brought about.

PRESSURE of the BLOOD on the ARTERIES and other BLOOD VESSELS.

The measurement of an organ in volume, mass, or heaviness.

The mass or quantity of heaviness of an individual. It is expressed by units of pounds or kilograms.

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 free radical gas produced endogenously by a variety of mammalian cells, synthesized from ARGININE by NITRIC OXIDE SYNTHASE. Nitric oxide is one of the ENDOTHELIUM-DEPENDENT RELAXING FACTORS released by the vascular endothelium and mediates VASODILATION. It also inhibits platelet aggregation, induces disaggregation of aggregated platelets, and inhibits platelet adhesion to the vascular endothelium. Nitric oxide activates cytosolic GUANYLATE CYCLASE and thus elevates intracellular levels of CYCLIC GMP.

Organic compounds that contain the -NCO radical.

Care of patients with deficiencies and abnormalities associated with the cardiopulmonary system. It includes the therapeutic use of medical gases and their administrative apparatus, environmental control systems, humidification, aerosols, ventilatory support, bronchopulmonary drainage and exercise, respiratory rehabilitation, assistance with cardiopulmonary resuscitation, and maintenance of natural, artificial, and mechanical airways.

A process involving chance used in therapeutic trials or other research endeavor for allocating experimental subjects, human or animal, between treatment and control groups, or among treatment groups. It may also apply to experiments on inanimate objects.

The application of suitable drug dosage forms to the skin for either local or systemic effects.

The exposure to potentially harmful chemical, physical, or biological agents that occurs as a result of one's occupation.

A chromone complex that acts by inhibiting the release of chemical mediators from sensitized mast cells. It is used in the prophylactic treatment of both allergic and exercise-induced asthma, but does not affect an established asthmatic attack.

Inhalation of oxygen aimed at restoring toward normal any pathophysiologic alterations of gas exchange in the cardiopulmonary system, as by the use of a respirator, nasal catheter, tent, chamber, or mask. (From Dorland, 27th ed & Stedman, 25th ed)

Agents causing the narrowing of the lumen of a bronchus or bronchiole.

A statistical technique that isolates and assesses the contributions of categorical independent variables to variation in the mean of a continuous dependent variable.

Earth or other matter in fine, dry particles. (Random House Unabridged Dictionary, 2d ed)

The movement and the forces involved in the movement of the blood through the CARDIOVASCULAR SYSTEM.

Unstable isotopes of oxygen that decay or disintegrate emitting radiation. O atoms with atomic weights 13, 14, 15, 19, and 20 are radioactive oxygen isotopes.

A stable, non-explosive inhalation anesthetic, relatively free from significant side effects.

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.

Chlorinated ethanes which are used extensively as industrial solvents. They have been utilized in numerous home-use products including spot remover preparations and inhalant decongestant sprays. These compounds cause central nervous system and cardiovascular depression and are hepatotoxic. Include 1,1,1- and 1,1,2-isomers.

Delivery of substances through VENIPUNCTURE into the VEINS.

Plutonium. A naturally radioactive element of the actinide metals series. It has the atomic symbol Pu, atomic number 94, and atomic weight 242. Plutonium is used as a nuclear fuel, to produce radioisotopes for research, in radionuclide batteries for pacemakers, and as the agent of fission in nuclear weapons.

Injections into the cerebral ventricles.

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. All animals within an inbred strain trace back to a common ancestor in the twentieth generation.

Infection of the lung often accompanied by inflammation.

The number of times the HEART VENTRICLES contract per unit of time, usually per minute.

A glucocorticoid used in the management of ASTHMA, the treatment of various skin disorders, and allergic RHINITIS.

A muscarinic antagonist structurally related to ATROPINE but often considered safer and more effective for inhalation use. It is used for various bronchial disorders, in rhinitis, and as an antiarrhythmic.

An albumin obtained from the white of eggs. It is a member of the serpin superfamily.

A selective beta-2 adrenergic agonist used as a bronchodilator and tocolytic.

Body organ that filters blood for the secretion of URINE and that regulates ion concentrations.

The vapor state of matter; nonelastic fluids in which the molecules are in free movement and their mean positions far apart. Gases tend to expand indefinitely, to diffuse and mix readily with other gases, to have definite relations of volume, temperature, and pressure, and to condense or liquefy at low temperatures or under sufficient pressure. (Grant & Hackh's Chemical Dictionary, 5th ed)

The total amount of a chemical, metal or radioactive substance present at any time after absorption in the body of man or animal.

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)

An acute infection caused by the spore-forming bacteria BACILLUS ANTHRACIS. It commonly affects hoofed animals such as sheep and goats. Infection in humans often involves the skin (cutaneous anthrax), the lungs (inhalation anthrax), or the gastrointestinal tract. Anthrax is not contagious and can be treated with antibiotics.

Organic salts of cyanic acid containing the -OCN radical.

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.

Antigen-type substances that produce immediate hypersensitivity (HYPERSENSITIVITY, IMMEDIATE).

The proximal portion of the respiratory passages on either side of the NASAL SEPTUM. Nasal cavities, extending from the nares to the NASOPHARYNX, are lined with ciliated NASAL MUCOSA.

Gases, fumes, vapors, and odors escaping from the cylinders of a gasoline or diesel internal-combustion engine. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed & Random House Unabridged Dictionary, 2d ed)

The observable response an animal makes to any situation.

A phase transition from liquid state to gas state, which is affected by Raoult's law. It can be accomplished by fractional distillation.

Uptake of substances through the SKIN.

Systems for the delivery of drugs to target sites of pharmacological actions. Technologies employed include those concerning drug preparation, route of administration, site targeting, metabolism, and toxicity.

Pathological processes involving any part of the LUNG.

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

Single preparations containing two or more active agents, for the purpose of their concurrent administration as a fixed dose mixture.

A sudden, audible expulsion of air from the lungs through a partially closed glottis, preceded by inhalation. It is a protective response that serves to clear the trachea, bronchi, and/or lungs of irritants and secretions, or to prevent aspiration of foreign materials into the lungs.

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.

An amine derived by enzymatic decarboxylation of HISTIDINE. It is a powerful stimulant of gastric secretion, a constrictor of bronchial smooth muscle, a vasodilator, and also a centrally acting neurotransmitter.

Hydrocarbons are organic compounds consisting entirely of hydrogen and carbon atoms, forming the basis of classes such as alkanes, alkenes, alkynes, and aromatic hydrocarbons, which play a vital role in energy production and chemical synthesis.

The circulation of blood through the BLOOD VESSELS of the BRAIN.

Substances that increase the risk of NEOPLASMS in humans or animals. Both genotoxic chemicals, which affect DNA directly, and nongenotoxic chemicals, which induce neoplasms by other mechanism, are included.

A pathological process characterized by injury or destruction of tissues caused by a variety of cytologic and chemical reactions. It is usually manifested by typical signs of pain, heat, redness, swelling, and loss of function.

A nonflammable, halogenated, hydrocarbon anesthetic that provides relatively rapid induction with little or no excitement. Analgesia may not be adequate. NITROUS OXIDE is often given concomitantly. Because halothane may not produce sufficient muscle relaxation, supplemental neuromuscular blocking agents may be required. (From AMA Drug Evaluations Annual, 1994, p178)

A clear, colorless liquid rapidly absorbed from the gastrointestinal tract and distributed throughout the body. It has bactericidal activity and is used often as a topical disinfectant. It is widely used as a solvent and preservative in pharmaceutical preparations as well as serving as the primary ingredient in ALCOHOLIC BEVERAGES.

Non-antibody proteins secreted by inflammatory leukocytes and some non-leukocytic cells, that act as intercellular mediators. They differ from classical hormones in that they are produced by a number of tissue or cell types rather than by specialized glands. They generally act locally in a paracrine or autocrine rather than endocrine manner.

The physical or mechanical action of the LUNGS; DIAPHRAGM; RIBS; and CHEST WALL during respiration. It includes airflow, lung volume, neural and reflex controls, mechanoreceptors, breathing patterns, etc.

The cartilaginous and membranous tube descending from the larynx and branching into the right and left main bronchi.

RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.

Progressive diminution of the susceptibility of a human or animal to the effects of a drug, resulting from its continued administration. It should be differentiated from DRUG RESISTANCE wherein an organism, disease, or tissue fails to respond to the intended effectiveness of a chemical or drug. It should also be differentiated from MAXIMUM TOLERATED DOSE and NO-OBSERVED-ADVERSE-EFFECT LEVEL.

Administration of a soluble dosage form by placement under the tongue.

Introduction of substances into the body using a needle and syringe.

Round, granular, mononuclear phagocytes found in the alveoli of the lungs. They ingest small inhaled particles resulting in degradation and presentation of the antigen to immunocompetent cells.

The principal alkaloid in opium and the prototype opiate analgesic and narcotic. Morphine has widespread effects in the central nervous system and on smooth muscle.

Inbred ICR mice are a strain of albino laboratory mice that have been selectively bred for consistent genetic makeup and high reproductive performance, making them widely used in biomedical research for studies involving reproduction, toxicology, pharmacology, and carcinogenesis.

A common name used for the genus Cavia. The most common species is Cavia porcellus which is the domesticated guinea pig used for pets and biomedical research.

The circulation of the BLOOD through the LUNGS.

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

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.

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

The administration of liquid medication, nutrient, or other fluid through some other route than the alimentary canal, usually over minutes or hours, either by gravity flow or often by infusion pumping.

AMINO ALCOHOLS containing the ETHANOLAMINE; (-NH2CH2CHOH) group and its derivatives.

The mucous lining of the NASAL CAVITY, including lining of the nostril (vestibule) and the OLFACTORY MUCOSA. Nasal mucosa consists of ciliated cells, GOBLET CELLS, brush cells, small granule cells, basal cells (STEM CELLS) and glands containing both mucous and serous cells.

A non-specific host defense mechanism that removes MUCUS and other material from the LUNGS by ciliary and secretory activity of the tracheobronchial submucosal glands. It is measured in vivo as mucus transfer, ciliary beat frequency, and clearance of radioactive tracers.

Drugs that are used to treat asthma.

A common interstitial lung disease caused by hypersensitivity reactions of PULMONARY ALVEOLI after inhalation of and sensitization to environmental antigens of microbial, animal, or chemical sources. The disease is characterized by lymphocytic alveolitis and granulomatous pneumonitis.

Therapy with two or more separate preparations given for a combined effect.

Drugs used to cause dilation of the blood vessels.

The status during which female mammals carry their developing young (EMBRYOS or FETUSES) in utero before birth, beginning from FERTILIZATION to BIRTH.

Substances that reduce or suppress INFLAMMATION.

Proteins prepared by recombinant DNA technology.

A form of hypersensitivity affecting the respiratory tract. It includes ASTHMA and RHINITIS, ALLERGIC, SEASONAL.

Any hindrance to the passage of air into and out of the lungs.

A noble gas with the atomic symbol Xe, atomic number 54, and atomic weight 131.30. It is found in the earth's atmosphere and has been used as an anesthetic.

The number of WHITE BLOOD CELLS per unit volume in venous BLOOD. A differential leukocyte count measures the relative numbers of the different types of white cells.

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.

An array of tests used to determine the toxicity of a substance to living systems. These include tests on clinical drugs, foods, and environmental pollutants.

Silicon polymers that contain alternate silicon and oxygen atoms in linear or cyclic molecular structures.

Any of the ruminant mammals with curved horns in the genus Ovis, family Bovidae. They possess lachrymal grooves and interdigital glands, which are absent in GOATS.

Compressed gases or vapors in a container which, upon release of pressure and expansion through a valve, carry another substance from the container. They are used for cosmetics, household cleaners, and so on. Examples are BUTANES; CARBON DIOXIDE; FLUOROCARBONS; NITROGEN; and PROPANE. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)

The unstable triatomic form of oxygen, O3. It is a powerful oxidant that is produced for various chemical and industrial uses. Its production is also catalyzed in the ATMOSPHERE by ULTRAVIOLET RAY irradiation of oxygen or other ozone precursors such as VOLATILE ORGANIC COMPOUNDS and NITROGEN OXIDES. About 90% of the ozone in the atmosphere exists in the stratosphere (STRATOSPHERIC OZONE).

Lipid-containing polysaccharides which are endotoxins and important group-specific antigens. They are often derived from the cell wall of gram-negative bacteria and induce immunoglobulin secretion. The lipopolysaccharide molecule consists of three parts: LIPID A, core polysaccharide, and O-specific chains (O ANTIGENS). When derived from Escherichia coli, lipopolysaccharides serve as polyclonal B-cell mitogens commonly used in laboratory immunology. (From Dorland, 28th ed)

Hypertonic sodium chloride solution. A solution having an osmotic pressure greater than that of physiologic salt solution (0.9 g NaCl in 100 ml purified water).

Particles of any solid substance, generally under 30 microns in size, often noted as PM30. There is special concern with PM1 which can get down to PULMONARY ALVEOLI and induce MACROPHAGE ACTIVATION and PHAGOCYTOSIS leading to FOREIGN BODY REACTION and LUNG DISEASES.

Small polyhedral outpouchings along the walls of the alveolar sacs, alveolar ducts and terminal bronchioles through the walls of which gas exchange between alveolar air and pulmonary capillary blood takes place.

Compounds with activity like OPIATE ALKALOIDS, acting at OPIOID RECEPTORS. Properties include induction of ANALGESIA or NARCOSIS.

Long, pliable, cohesive natural or manufactured filaments of various lengths. They form the structure of some minerals. The medical significance lies in their potential ability to cause various types of PNEUMOCONIOSIS (e.g., ASBESTOSIS) after occupational or environmental exposure. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed, p708)

Forms to which substances are incorporated to improve the delivery and the effectiveness of drugs. Drug carriers are used in drug-delivery systems such as the controlled-release technology to prolong in vivo drug actions, decrease drug metabolism, and reduce drug toxicity. Carriers are also used in designs to increase the effectiveness of drug delivery to the target sites of pharmacological actions. Liposomes, albumin microspheres, soluble synthetic polymers, DNA complexes, protein-drug conjugates, and carrier erythrocytes among others have been employed as biodegradable drug carriers.

The exchange of OXYGEN and CARBON DIOXIDE between alveolar air and pulmonary capillary blood that occurs across the BLOOD-AIR BARRIER.

Non-human animals, selected because of specific characteristics, for use in experimental research, teaching, or testing.

Compounds or agents that combine with an enzyme in such a manner as to prevent the normal substrate-enzyme combination and the catalytic reaction.

Spasmodic contraction of the smooth muscle of the bronchi.

An eicosanoid, derived from the cyclooxygenase pathway of arachidonic acid metabolism. It is a stable and synthetic analog of EPOPROSTENOL, but with a longer half-life than the parent compound. Its actions are similar to prostacyclin. Iloprost produces vasodilation and inhibits platelet aggregation.

Substances that reduce the growth or reproduction of BACTERIA.

An anti-inflammatory, synthetic glucocorticoid. It is used topically as an anti-inflammatory agent and in aerosol form for the treatment of ASTHMA.

Methods of creating machines and devices.

The physical activity of a human or an animal as a behavioral phenomenon.

An encapsulated lymphatic organ through which venous blood filters.

Introduction of therapeutic agents into the spinal region using a needle and syringe.

Administration of a drug or chemical by the individual under the direction of a physician. It includes administration clinically or experimentally, by human or animal.

An adrenergic beta-2 agonist that is used as a bronchodilator and tocolytic.

The flow of BLOOD through or around an organ or region of the body.

Oils which evaporate readily. The volatile oils occur in aromatic plants, to which they give odor and other characteristics. Most volatile oils consist of a mixture of two or more TERPENES or of a mixture of an eleoptene (the more volatile constituent of a volatile oil) with a stearopten (the more solid constituent). The synonym essential oils refers to the essence of a plant, as its perfume or scent, and not to its indispensability.

Experiments designed to determine the potential toxic effects of one-time, short-term exposure to a chemical or chemicals.

Nanometer-sized particles that are nanoscale in three dimensions. They include nanocrystaline materials; NANOCAPSULES; METAL NANOPARTICLES; DENDRIMERS, and QUANTUM DOTS. The uses of nanoparticles include DRUG DELIVERY SYSTEMS and cancer targeting and imaging.

Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.

The chemical alteration of an exogenous substance by or in a biological system. The alteration may inactivate the compound or it may result in the production of an active metabolite of an inactive parent compound. The alterations may be divided into METABOLIC DETOXICATION, PHASE I and METABOLIC DETOXICATION, PHASE II.

Fluorinated hydrocarbons are organic compounds consisting primarily of carbon and fluorine atoms, where hydrogen atoms may also be present, known for their high stability, chemical resistance, and various industrial applications, including refrigerants, fire extinguishing agents, and electrical insulation materials.

'Fires' is not a recognized medical term for a symptom, diagnosis, or condition in patients.

Granular leukocytes having a nucleus with three to five lobes connected by slender threads of chromatin, and cytoplasm containing fine inconspicuous granules and stainable by neutral dyes.

The total volume of gas inspired or expired per unit of time, usually measured in liters per minute.

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.

Preclinical testing of drugs in experimental animals or in vitro for their biological and toxic effects and potential clinical applications.

A family of hexahydropyridines.

The highest dosage administered that does not produce toxic effects.

The action of a drug in promoting or enhancing the effectiveness of another drug.

Serum glycoprotein produced by activated MACROPHAGES and other mammalian MONONUCLEAR LEUKOCYTES. It has necrotizing activity against tumor cell lines and increases ability to reject tumor transplants. Also known as TNF-alpha, it is only 30% homologous to TNF-beta (LYMPHOTOXIN), but they share TNF RECEPTORS.

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.

The use of fragrances and essences from plants to affect or alter a person's mood or behavior and to facilitate physical, mental, and emotional well-being. The chemicals comprising essential oils in plants has a host of therapeutic properties and has been used historically in Africa, Asia, and India. Its greatest application is in the field of alternative medicine. (From Random House Unabridged Dictionary, 2d ed; from Dr. Atiba Vheir, Dove Center, Washington, D.C.)

A state characterized by loss of feeling or sensation. This depression of nerve function is usually the result of pharmacologic action and is induced to allow performance of surgery or other painful procedures.

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.

Substances that inhibit or prevent the proliferation of NEOPLASMS.

Agents that are capable of inducing a total or partial loss of sensation, especially tactile sensation and pain. They may act to induce general ANESTHESIA, in which an unconscious state is achieved, or may act locally to induce numbness or lack of sensation at a targeted site.