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).

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.

Methods, procedures, and tests performed to diagnose disease, disordered function, or disability.

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 capability of the LUNGS to distend under pressure as measured by pulmonary volume change per unit pressure change. While not a complete description of the pressure-volume properties of the lung, it is nevertheless useful in practice as a measure of the comparative stiffness of the lung. (From Best & Taylor's Physiological Basis of Medical Practice, 12th ed, p562)

MOLECULAR BIOLOGY techniques used in the diagnosis of disease.

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.

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.

Physiological processes and properties of the RESPIRATORY SYSTEM as a whole or of any of its parts.

Any diagnostic evaluation using radioactive (unstable) isotopes. This diagnosis includes many nuclear medicine procedures as well as radioimmunoassay tests.

Methods and procedures for the diagnosis of diseases of the ear or of hearing disorders or demonstration of hearing acuity or loss.

Methods and procedures for the diagnosis of disease or dysfunction by examination of the pathological site or operative field during surgical intervention.

Congenital structural abnormalities of the respiratory system.

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

Measurement of the amount of air that the lungs may contain at various points in the respiratory cycle.

PHENOTHIAZINES with an amino group at the 3-position that are green crystals or powder. They are used as biological stains.

In vitro method for producing large amounts of specific DNA or RNA fragments of defined length and sequence from small amounts of short oligonucleotide flanking sequences (primers). The essential steps include thermal denaturation of the double-stranded target molecules, annealing of the primers to their complementary sequences, and extension of the annealed primers by enzymatic synthesis with DNA polymerase. The reaction is efficient, specific, and extremely sensitive. Uses for the reaction include disease diagnosis, detection of difficult-to-isolate pathogens, mutation analysis, genetic testing, DNA sequencing, and analyzing evolutionary relationships.

Methods and procedures for the diagnosis of diseases of the respiratory tract or its organs. It includes RESPIRATORY FUNCTION TESTS.

Methods and procedures for the diagnosis of diseases or dysfunction of the urinary tract or its organs or demonstration of its physiological processes.

Methods and procedures for the diagnosis of conditions related to pregnancy, labor, and the puerperium and of diseases of the female genitalia. It includes also demonstration of genital and pregnancy physiology.

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

Diagnostic procedures, such as laboratory tests and x-rays, routinely performed on all individuals or specified categories of individuals in a specified situation, e.g., patients being admitted to the hospital. These include routine tests administered to neonates.

Methods and procedures for the diagnosis of diseases or dysfunction of the digestive system or its organs or demonstration of their physiological processes.

Drugs that are used to treat asthma.

The volume of air remaining in the LUNGS at the end of a normal, quiet expiration. It is the sum of the RESIDUAL VOLUME and the EXPIRATORY RESERVE VOLUME. Common abbreviation is FRC.

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).

The volume of air inspired or expired during each normal, quiet respiratory cycle. Common abbreviations are TV or V with subscript T.

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.

Measurement of volume of air inhaled or exhaled by the lung.

Techniques used to carry out clinical investigative procedures in the diagnosis and therapy of disease.

Any method of artificial breathing that employs mechanical or non-mechanical means to force the air into and out of the lungs. Artificial respiration or ventilation is used in individuals who have stopped breathing or have RESPIRATORY INSUFFICIENCY to increase their intake of oxygen (O2) and excretion of carbon dioxide (CO2).

Thin-walled sacs or spaces which function as a part of the respiratory system in birds, fishes, insects, and mammals.

The measurement of frequency or oscillation changes.

The force per unit area that the air exerts on any surface in contact with it. Primarily used for articles pertaining to air pressure within a closed environment.

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.

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

Diagnosis of the type and, when feasible, the cause of a pathologic process by means of microscopic study of cells in an exudate or other form of body fluid. (Stedman, 26th ed)

Tomography using x-ray transmission and a computer algorithm to reconstruct the image.

Methods and procedures for the diagnosis of diseases of the nervous system, central and peripheral, or demonstration of neurologic function or dysfunction.

Respiratory tract diseases are a broad range of medical conditions that affect the nose, throat, windpipe, and lungs, impairing breathing and oxygen uptake, including asthma, chronic obstructive pulmonary disease (COPD), pneumonia, bronchitis, influenza, tuberculosis, and sleep apnea.

In screening and diagnostic tests, the probability that a person with a positive test is a true positive (i.e., has the disease), is referred to as the predictive value of a positive test; whereas, the predictive value of a negative test is the probability that the person with a negative test does not have the disease. Predictive value is related to the sensitivity and specificity of the test.

A method of mechanical ventilation in which pressure is maintained to increase the volume of gas remaining in the lungs at the end of expiration, thus reducing the shunting of blood through the lungs and improving gas exchange.

The study of parasites and PARASITIC DISEASES.

Endoscopic examination, therapy or surgery of the bronchi.

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

The production of an image obtained by cameras that detect the radioactive emissions of an injected radionuclide as it has distributed differentially throughout tissues in the body. The image obtained from a moving detector is called a scan, while the image obtained from a stationary camera device is called a scintiphotograph.

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

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)

Removal and examination of tissue obtained through a transdermal needle inserted into the specific region, organ, or tissue being analyzed.

Observation of a population for a sufficient number of persons over a sufficient number of years to generate incidence or mortality rates subsequent to the selection of the study group.

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.

Methods and procedures for the diagnosis of diseases or dysfunction of the endocrine glands or demonstration of their physiological processes.

The visualization of deep structures of the body by recording the reflections or echoes of ultrasonic pulses directed into the tissues. Use of ultrasound for imaging or diagnostic purposes employs frequencies ranging from 1.6 to 10 megahertz.

Removal and pathologic examination of specimens in the form of small pieces of tissue from the living body.

Studies used to test etiologic hypotheses in which inferences about an exposure to putative causal factors are derived from data relating to characteristics of persons under study or to events or experiences in their past. The essential feature is that some of the persons under study have the disease or outcome of interest and their characteristics are compared with those of unaffected persons.

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.

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

The total number of cases of a given disease in a specified population at a designated time. It is differentiated from INCIDENCE, which refers to the number of new cases in the population at a given time.

Measurement of the maximum rate of airflow attained during a FORCED VITAL CAPACITY determination. Common abbreviations are PEFR and PFR.

Noises, normal and abnormal, heard on auscultation over any part of the RESPIRATORY TRACT.

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

The use of instrumentation and techniques for visualizing material and details that cannot be seen by the unaided eye. It is usually done by enlarging images, transmitted by light or electron beams, with optical or magnetic lenses that magnify the entire image field. With scanning microscopy, images are generated by collecting output from the specimen in a point-by-point fashion, on a magnified scale, as it is scanned by a narrow beam of light or electrons, a laser, a conductive probe, or a topographical probe.

Using fine needles (finer than 22-gauge) to remove tissue or fluid specimens from the living body for examination in the pathology laboratory and for disease diagnosis.

Asthma attacks following a period of exercise. Usually the induced attack is short-lived and regresses spontaneously. The magnitude of postexertional airway obstruction is strongly influenced by the environment in which exercise is performed (i.e. inhalation of cold air during physical exertion markedly augments the severity of the airway obstruction; conversely, warm humid air blunts or abolishes it).

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

Techniques used in studying bacteria.

A species of migratory Old World locusts, in the family ACRIDIDAE, that are important pests in Africa and Asia.

Non-invasive method of demonstrating internal anatomy based on the principle that atomic nuclei in a strong magnetic field absorb pulses of radiofrequency energy and emit them as radiowaves which can be reconstructed into computerized images. The concept includes proton spin tomographic techniques.

An immunoassay utilizing an antibody labeled with an enzyme marker such as horseradish peroxidase. While either the enzyme or the antibody is bound to an immunosorbent substrate, they both retain their biologic activity; the change in enzyme activity as a result of the enzyme-antibody-antigen reaction is proportional to the concentration of the antigen and can be measured spectrophotometrically or with the naked eye. Many variations of the method have been developed.

Methods and procedures for the diagnosis of diseases or dysfunction of the cardiovascular system or its organs or demonstration of their physiological processes.

The upper part of the trunk between the NECK and the ABDOMEN. It contains the chief organs of the circulatory and respiratory systems. (From Stedman, 25th ed)

An infant during the first month after birth.

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.

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

Complete or severe weakness of the muscles of respiration. This condition may be associated with MOTOR NEURON DISEASES; PERIPHERAL NERVE DISEASES; NEUROMUSCULAR JUNCTION DISEASES; SPINAL CORD DISEASES; injury to the PHRENIC NERVE; and other disorders.

Excrement from the INTESTINES, containing unabsorbed solids, waste products, secretions, and BACTERIA of the DIGESTIVE SYSTEM.

An aspect of personal behavior or lifestyle, environmental exposure, or inborn or inherited characteristic, which, on the basis of epidemiologic evidence, is known to be associated with a health-related condition considered important to prevent.

The volume of air contained in the lungs at the end of a maximal inspiration. It is the equivalent to each of the following sums: VITAL CAPACITY plus RESIDUAL VOLUME; INSPIRATORY CAPACITY plus FUNCTIONAL RESIDUAL CAPACITY; TIDAL VOLUME plus INSPIRATORY RESERVE VOLUME plus functional residual capacity; or tidal volume plus inspiratory reserve volume plus EXPIRATORY RESERVE VOLUME plus residual volume.

Diseases of the domestic dog (Canis familiaris). This term does not include diseases of wild dogs, WOLVES; FOXES; and other Canidae for which the heading CARNIVORA is used.

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

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

A syndrome characterized by progressive life-threatening RESPIRATORY INSUFFICIENCY in the absence of known LUNG DISEASES, usually following a systemic insult such as surgery or major TRAUMA.

Diseases of the respiratory system in general or unspecified or for a specific respiratory disease not available.

Mycoses are a group of diseases caused by fungal pathogens that can infect various tissues and organs, potentially leading to localized or systemic symptoms, depending on the immune status of the host.

Incorrect diagnoses after clinical examination or technical diagnostic procedures.

Pathological processes involving any part of the LUNG.

Asthma attacks caused, triggered, or exacerbated by OCCUPATIONAL EXPOSURE.

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.

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 act of BREATHING out.

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.

Substances used to allow enhanced visualization of tissues.

Respiratory Tract Neoplasms are defined as abnormal growths or tumors that develop within the respiratory system, including the nose, sinuses, throat (pharynx), voice box (larynx), windpipe (trachea), bronchi, and lungs, which can be benign or malignant, with the potential to cause significant morbidity and mortality.

Mechanical devices used to produce or assist pulmonary ventilation.

The volume of air that is exhaled by a maximal expiration following a maximal inspiration.

Absence of air in the entire or part of a lung, such as an incompletely inflated neonate lung or a collapsed adult lung. Pulmonary atelectasis can be caused by airway obstruction, lung compression, fibrotic contraction, or other factors.

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

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.

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 outer margins of the thorax containing SKIN, deep FASCIA; THORACIC VERTEBRAE; RIBS; STERNUM; and MUSCLES.

Adrenal cortex hormones are steroid hormones produced by the outer portion of the adrenal gland, consisting of glucocorticoids, mineralocorticoids, and androgens, which play crucial roles in various physiological processes such as metabolism regulation, stress response, electrolyte balance, and sexual development and function.

The volume of air remaining in the LUNGS at the end of a maximal expiration. Common abbreviation is RV.

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)

Failure to adequately provide oxygen to cells of the body and to remove excess carbon dioxide from them. (Stedman, 25th ed)

Measurable and quantifiable biological parameters (e.g., specific enzyme concentration, specific hormone concentration, specific gene phenotype distribution in a population, presence of biological substances) which serve as indices for health- and physiology-related assessments, such as disease risk, psychiatric disorders, environmental exposure and its effects, disease diagnosis, metabolic processes, substance abuse, pregnancy, cell line development, epidemiologic studies, etc.

Studies in which individuals or populations are followed to assess the outcome of exposures, procedures, or effects of a characteristic, e.g., occurrence of disease.

Measurement of the volume of gas in the lungs, including that which is trapped in poorly communicating air spaces. It is of particular use in chronic obstructive pulmonary disease and emphysema. (Segen, Dictionary of Modern Medicine, 1992)

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)

Immunologic techniques based on the use of: (1) enzyme-antibody conjugates; (2) enzyme-antigen conjugates; (3) antienzyme antibody followed by its homologous enzyme; or (4) enzyme-antienzyme complexes. These are used histologically for visualizing or labeling tissue specimens.

Inflammation of the large airways in the lung including any part of the BRONCHI, from the PRIMARY BRONCHI to the TERTIARY BRONCHI.

Altered reactivity to an antigen, which can result in pathologic reactions upon subsequent exposure to that particular antigen.

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.

Levels within a diagnostic group which are established by various measurement criteria applied to the seriousness of a patient's disorder.

Diseases caused by factors involved in one's employment.

Hospitals controlled by the county government.

Any disorder marked by obstruction of conducting airways of the lung. AIRWAY OBSTRUCTION may be acute, chronic, intermittent, or persistent.

Deoxyribonucleic acid that makes up the genetic material of bacteria.

The act of BREATHING in.

The number of times an organism breathes with the lungs (RESPIRATION) per unit time, usually per minute.

A type of stress exerted uniformly in all directions. Its measure is the force exerted per unit area. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)

The number of new cases of a given disease during a given period in a specified population. It also is used for the rate at which new events occur in a defined population. It is differentiated from PREVALENCE, which refers to all cases, new or old, in the population at a given time.

The term "United States" in a medical context often refers to the country where a patient or study participant resides, and is not a medical term per se, but relevant for epidemiological studies, healthcare policies, and understanding differences in disease prevalence, treatment patterns, and health outcomes across various geographic locations.

The extra volume of air that can be expired with maximum effort beyond the level reached at the end of a normal, quiet expiration. Common abbreviation is ERV.

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.

Hypersensitivity reactions which occur within minutes of exposure to challenging antigen due to the release of histamine which follows the antigen-antibody reaction and causes smooth muscle contraction and increased vascular permeability.

General name for two extinct orders of reptiles from the Mesozoic era: Saurischia and Ornithischia.

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

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

Any visual display of structural or functional patterns of organs or tissues for diagnostic evaluation. It includes measuring physiologic and metabolic responses to physical and chemical stimuli, as well as ultramicroscopy.

Resistance and recovery from distortion of shape.

A disease of chronic diffuse irreversible airflow obstruction. Subcategories of COPD include CHRONIC BRONCHITIS and PULMONARY EMPHYSEMA.

A prediction of the probable outcome of a disease based on a individual's condition and the usual course of the disease as seen in similar situations.

Short sequences (generally about 10 base pairs) of DNA that are complementary to sequences of messenger RNA and allow reverse transcriptases to start copying the adjacent sequences of mRNA. Primers are used extensively in genetic and molecular biology techniques.

Invasion of the host RESPIRATORY SYSTEM by microorganisms, usually leading to pathological processes or diseases.

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.

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.

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.

Sudden increase in the incidence of a disease. The concept includes EPIDEMICS and PANDEMICS.

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

Inflammation of the NASAL MUCOSA, the mucous membrane lining the NASAL CAVITIES.

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

Test for tissue antigen using either a direct method, by conjugation of antibody with fluorescent dye (FLUORESCENT ANTIBODY TECHNIQUE, DIRECT) or an indirect method, by formation of antigen-antibody complex which is then labeled with fluorescein-conjugated anti-immunoglobulin antibody (FLUORESCENT ANTIBODY TECHNIQUE, INDIRECT). The tissue is then examined by fluorescence microscopy.

Damage to any compartment of the lung caused by physical, chemical, or biological agents which characteristically elicit inflammatory reaction. These inflammatory reactions can either be acute and dominated by NEUTROPHILS, or chronic and dominated by LYMPHOCYTES and MACROPHAGES.

A procedure involving placement of a tube into the trachea through the mouth or nose in order to provide a patient with oxygen and anesthesia.

The maximum volume of air that can be inspired after reaching the end of a normal, quiet expiration. It is the sum of the TIDAL VOLUME and the INSPIRATORY RESERVE VOLUME. Common abbreviation is IC.

The rate of airflow measured during a FORCED VITAL CAPACITY determination.

A condition of the newborn marked by DYSPNEA with CYANOSIS, heralded by such prodromal signs as dilatation of the alae nasi, expiratory grunt, and retraction of the suprasternal notch or costal margins, mostly frequently occurring in premature infants, children of diabetic mothers, and infants delivered by cesarean section, and sometimes with no apparent predisposing cause.

A technique of inputting two-dimensional images into a computer and then enhancing or analyzing the imagery into a form that is more useful to the human observer.

Helium. A noble gas with the atomic symbol He, atomic number 2, and atomic weight 4.003. It is a colorless, odorless, tasteless gas that is not combustible and does not support combustion. It was first detected in the sun and is now obtained from natural gas. Medically it is used as a diluent for other gases, being especially useful with oxygen in the treatment of certain cases of respiratory obstruction, and as a vehicle for general anesthetics. (Dorland, 27th ed)

These include the muscles of the DIAPHRAGM and the INTERCOSTAL MUSCLES.

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.

Large, long-tailed reptiles, including caimans, of the order Loricata.

RESPIRATORY MUSCLE contraction during INHALATION. The work is accomplished in three phases: LUNG COMPLIANCE work, that required to expand the LUNGS against its elastic forces; tissue resistance work, that required to overcome the viscosity of the lung and chest wall structures; and AIRWAY RESISTANCE work, that required to overcome airway resistance during the movement of air into the lungs. Work of breathing does not refer to expiration, which is entirely a passive process caused by elastic recoil of the lung and chest cage. (Guyton, Textbook of Medical Physiology, 8th ed, p406)

Cytochromes (electron-transporting proteins) in which the heme prosthetic group is heme a, i.e., the iron chelate of cytoporphyrin IX. (From Enzyme Nomenclature, 1992, p539)

Studies which start with the identification of persons with a disease of interest and a control (comparison, referent) group without the disease. The relationship of an attribute to the disease is examined by comparing diseased and non-diseased persons with regard to the frequency or levels of the attribute in each group.

Non-therapeutic positive end-expiratory pressure occurring frequently in patients with severe airway obstruction. It can appear with or without the administration of external positive end-expiratory pressure (POSITIVE-PRESSURE RESPIRATION). It presents an important load on the inspiratory muscles which are operating at a mechanical disadvantage due to hyperinflation. Auto-PEEP may cause profound hypotension that should be treated by intravascular volume expansion, increasing the time for expiration, and/or changing from assist mode to intermittent mandatory ventilation mode. (From Harrison's Principles of Internal Medicine, 12th ed, p1127)

Inflammation of the mucous membrane of the nose similar to that found in hay fever except that symptoms persist throughout the year. The causes are usually air-borne allergens, particularly dusts, feathers, molds, animal fur, etc.

Diseases which have one or more of the following characteristics: they are permanent, leave residual disability, are caused by nonreversible pathological alteration, require special training of the patient for rehabilitation, or may be expected to require a long period of supervision, observation, or care. (Dictionary of Health Services Management, 2d ed)

The viscous secretion of mucous membranes. It contains mucin, white blood cells, water, inorganic salts, and exfoliated cells.

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).

Studies in which the presence or absence of disease or other health-related variables are determined in each member of the study population or in a representative sample at one particular time. This contrasts with LONGITUDINAL STUDIES which are followed over a period of time.

Histochemical localization of immunoreactive substances using labeled antibodies as reagents.

The mixture of gases present in the earth's atmosphere consisting of oxygen, nitrogen, carbon dioxide, and small amounts of other gases.

A subcategory of CHRONIC OBSTRUCTIVE PULMONARY DISEASE. The disease is characterized by hypersecretion of mucus accompanied by a chronic (more than 3 months in 2 consecutive years) productive cough. Infectious agents are a major cause of chronic bronchitis.

That part of the RESPIRATORY TRACT or the air within the respiratory tract that does not exchange OXYGEN and CARBON DIOXIDE with pulmonary capillary blood.

A highly poisonous compound that is an inhibitor of many metabolic processes, but has been shown to be an especially potent inhibitor of heme enzymes and hemeproteins. It is used in many industrial processes.

HYPOVENTILATION syndrome in very obese persons with excessive ADIPOSE TISSUE around the ABDOMEN and DIAPHRAGM. It is characterized by diminished to absent ventilatory chemoresponsiveness; chronic HYPOXIA; HYPERCAPNIA; POLYCYTHEMIA; and long periods of sleep during day and night (HYPERSOMNOLENCE). It is a condition often related to OBSTRUCTIVE SLEEP APNEA but can occur separately.

The musculofibrous partition that separates the THORACIC CAVITY from the ABDOMINAL CAVITY. Contraction of the diaphragm increases the volume of the thoracic cavity aiding INHALATION.

The HEART and the BLOOD VESSELS by which BLOOD is pumped and circulated through the body.

Epicutaneous or intradermal application of a sensitizer for demonstration of either delayed or immediate hypersensitivity. Used in diagnosis of hypersensitivity or as a test for cellular immunity.

Predetermined sets of questions used to collect data - clinical data, social status, occupational group, etc. The term is often applied to a self-completed survey instrument.

Granular leukocytes with a nucleus that usually has two lobes connected by a slender thread of chromatin, and cytoplasm containing coarse, round granules that are uniform in size and stainable by eosin.

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

A pulmonary ventilation rate faster than is metabolically necessary for the exchange of gases. It is the result of an increased frequency of breathing, an increased tidal volume, or a combination of both. It causes an excess intake of oxygen and the blowing off of carbon dioxide.

Recording of change in the size of a part as modified by the circulation in it.

A pathological accumulation of air in tissues or organs.

Studies in which subsets of a defined population are identified. These groups may or may not be exposed to factors hypothesized to influence the probability of the occurrence of a particular disease or other outcome. Cohorts are defined populations which, as a whole, are followed in an attempt to determine distinguishing subgroup characteristics.

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.

Ventilatory support system using frequencies from 60-900 cycles/min or more. Three types of systems have been distinguished on the basis of rates, volumes, and the system used. They are high frequency positive-pressure ventilation (HFPPV); HIGH-FREQUENCY JET VENTILATION; (HFJV); and high-frequency oscillation (HFO).

The motor nerve of the diaphragm. The phrenic nerve fibers originate in the cervical spinal column (mostly C4) and travel through the cervical plexus to the diaphragm.

Commercially prepared reagent sets, with accessory devices, containing all of the major components and literature necessary to perform one or more designated diagnostic tests or procedures. They may be for laboratory or personal use.

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

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

A measure of the amount of WATER VAPOR in the air.

A class of drugs designed to prevent leukotriene synthesis or activity by blocking binding at the receptor level.

Measurement of oxygen and carbon dioxide in the blood.

Inhaling and exhaling the smoke of burning TOBACCO.

Used in the form of the hydrochloride as a reagent in ANALYTICAL CHEMISTRY TECHNIQUES.

The biological science concerned with the life-supporting properties, functions, and processes of living organisms or their parts.

Devices that cause a liquid or solid to be converted into an aerosol (spray) or a vapor. It is used in drug administration by inhalation, humidification of ambient air, and in certain analytical instruments.

The 8-hydroxy derivatives inhibit various enzymes and their halogenated derivatives, though neurotoxic, are used as topical anti-infective agents, among other uses.

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.

Difficult or labored breathing.

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.

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 muscular membranous segment between the PHARYNX and the STOMACH in the UPPER GASTROINTESTINAL TRACT.

Processes and properties of the CARDIOVASCULAR SYSTEM as a whole or of any of its parts.

The posture of an individual lying face down.

Chemicals that are used to cause the disturbance, disease, or death of humans during WARFARE.

Methods and procedures for the diagnosis of diseases of the eye or of vision disorders.

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.

A sudden intense and continuous aggravation of a state of asthma, marked by dyspnea to the point of exhaustion and collapse and not responding to the usual therapeutic efforts.